Human activities are placing enormous pressures on the biosphere. The introduction of new chemicals and the increasing ambient levels of existing chemicals have resulted in atmospheric degradation. This paper reviews some of the adverse effects of stratospheric ozone depletion and global warming. Because the atmospheric effects of ozone depletion are fairly well characterized| quantitative risk estimates have been developed. However| because the atmospheric effects of global warming are less understood| public health problems that could be intensified by climate change are assessed qualitatively. The interactive effects of these two phenomena are also discussed.
3576,1991,2,4,APPROACHES TO THE CONSERVATION OF COASTAL WETLANDS IN THE WESTERN-HEMISPHERE,Coastal wetlands rank among the most productive and ecologically valuable natural ecosystems on Earth. Unfortunately| they are also some of the most disturbed. Because they are productive and can serve as transportation arteries| coastal wetlands have long attracted human settlement. More than half of the U.S. population currently lives within 80 km of its coasts| and one estimate places 70% of all humanity in the coastal zone. Human impacts to coastal wetlands include physical alteration of hydrological processes; the introduction of toxic materials| nutrients| heat| and exotic species; and the unsustainable harvest of native species. Between 1950 and 1970| coastal wetland losses in the U.S. averaged 8100 ha/year. In Central and South America| development pressures along the coastal zone rank among the most serious natural resource problems in the region. Here| we (1) briefly describe coastal wetland avifauna| (2) discuss the threat of global warming on coastal wetlands| (3) use several Western Hemisphere wetlands as site-specific examples of development pressures facing these habitats| and (4) provide synopses of non-governmental and governmental approaches to wetland conservation. Overall| we provide a socio-economic context for conservation of coastal wetlands in the wetlands in the Western Hemisphere. We suggest that efforts aimed at conserving sites of particular importance for their biological diversity should be pursued within a framework of wise use that addresses the broader issues of human population growth and economic development. 3561,1991,4,4,ATMOSPHERIC FATE OF CF2H2| CH3CF3| CHF2CF3| AND CH3CFCL2 - RATE COEFFICIENTS FOR REACTIONS WITH OH AND UV ABSORPTION CROSS-SECTIONS OF CH3CFCL2,The absolute rates coefficients for reactions of hydroxyl radical with four halocarbons (CH2F2(HFC-32)| CH3CF3(HFC-143a)| CF3CHF2(HFC-125)| and CH3CFCl2(HCFC-141b))| which are potential substitutes for CFCs| were measured by using the discharge flow-laser magnetic resonance and pulsed photolysis-laser-induced fluorescence techniques between 222 and 393 K. The UV absorption cross sections for HCFC-141b between 190 and 230 nm were also measured as functions of temperature. These kinetics and cross-section data are compared with results from previous studies. These data were incorporated into a one-dimensional photochemical transport model to estimate the tropospheric and atmospheric lifetimes needed to assess the ozone depletion potential and the global warming potential of these substitutes. The atmospheric lifetime of CH3CHCl2 (HCFC-141b) is approximately 50% longer than the previously accepted value. 3612,1991,2,2,ATMOSPHERIC METHANE - ITS CONTRIBUTION TO GLOBAL WARMING,Methane| a significant atmospheric trace-gas| controls numerous chemical processes and species in the troposphere and stratosphere. Its concentration in the Earth's atmosphere has been increasing at a rate of about 1% per year during the last century| and reached 1.72 ppmv in 1990. Methane is a strong greenhouse gas with significantly adverse environmental impacts. On a molecule-for-molecule basis| it is more than 20 times as potent a greenhouse gas as carbon dioxide. The contribution of methane to global warming between 1880 and 1980 has been estimated to be about 15%| with an increasing share| approximately 18%| during the 1980s. In this paper methods for estimating the change in atmospheric concentration of methane| and for predicting its global-warming effect| are described. Influences of some of the suggested emission-control policies are also discussed. Methane concentration in the atmosphere might reach a value of more than 4 ppmv by the end of the next century with no control policies implemented. This could produce an unavoidable long-term mean rise in the surface temperature of the Earth of more than 0.5-degrees-C. 2162,1991,4,4,ATMOSPHERIC POLLUTANTS AND ECTOMYCORRHIZAE - MORE QUESTIONS THAN ANSWERS,Changes in research emphasis from pollution towards the effects of climate change have resulted from shifts in political and public interests. Information gained from research on the effects of pollutants as a perturbation on mycorrhizae and mycorrhizae-mediated processes may be an appropriate starting point from which to launch into climate change studies. However| the effects of pollution on mycorrhizae are not clear cut as there are many conflicting results. The methods used in experiments| levels of pollutants used and relationships between studies on seedling trees to the mature forest do not suggest unifying models of pollution effects. Some areas of work still lacking in the pollution field are highlighted. These include well replicated experiments at currently ambient pollutant levels| and areas for potential development in the global climate change arena| e.g. the interaction between C supply and nutrient uptake. 2145,1991,3,4,BENEFIT-COST IMPLICATIONS OF ACID-RAIN CONTROLS - AN EVALUATION OF THE NAPAP INTEGRATED ASSESSMENT,Concluding ten years of study| the U.S. National Acid Precipitation Assessment Program (NAPAP) recently issued its integrated assessment report designed to provide guidance to policy makers on the sources and effects of acid deposition| and the costs and benefits of alternative control measures. This paper focuses on an evaluation of the benefit-cost implications of acid rain controls as revealed by two of the five major questions addressed in the NAPAP assessment framework. While the NAPAP effort made significant scientific contributions to the study of acid deposition| key gaps are found in the assessment of benefits and costs most relevant to policy decisions. Lessons learned from NAPAP may be helpful in avoiding similar problems in assessing emerging environmental issues such as global climate change. 2135,1991,2,2,BIOLOGICAL DIVERSITY AND NEPTUNE REALM,The diverse biological life in both terrestrial and marine environments offers mankind many practical and potential resources. These natural pools of wealth are under continuous pressure from various humanly induced alterations. Areas of current research are attempting to challenge the assorted problems| but many of the issues have yet to be addressed fully. Global climate change and soaring extinction rates appear to be the consequence of anthropogenic effects. Important preventive action is needed to restrict the forcing mechanisms for climate change being created by altered atmospheric composition. 2130,1991,2,2,BIOLOGICAL DIVERSITY| ECOLOGY| AND GLOBAL CLIMATE CHANGE,Worldwide climate change and loss of biodiversity are issues of global scope and importance that have recently become subjects of considerable public concern. Unlike classical public health issues and many environmental issues| their perceived threat lies in their potential to disrupt ecological functioning and stability rather than from any direct threat they may pose to human health. Over the last 5 years| the international scientific community and the general public have become aware of the implications that atmospheric warming might have for world climate patterns and the resulting changes in the persistence| location| and composition of ecosystems worldwide. At the same time| awareness of the magnitude of current and impending losses of the world's biological diversity has increased. Human activities are currently responsible for a species loss rate that is the most extreme in millions of years| and an alarmingly increasing rate of transformation and fragmentation of natural landscapes. We are just beginning to grasp the meaning of this loss in terms of opportunity costs to human society and the less quantifiable losses associated with simplification of natural ecosystems. In the case of both global warming and reduction of biological diversity| man is affecting nature in an unprecedented fashion| on a global scale| and with unpredictable and frequently irreversible results. 2154,1991,4,4,BIOLOGICAL RESPONSE TO CLIMATE CHANGE - AN AGENDA FOR RESEARCH,Our knowledge of the structure and functioning of terrestrial ecosystems on a global scale is not developed to a sufficient degree to understand - much less predict - the consequences of climate change either on the systems themselves or on subsequent atmospheric interactions. In many regards we have lagged behind the atmospheric scientists| and to a certain degree the oceanographers| in establishing a global understanding of the dynamics of our respective systems. This is due in part to the inherently greater complexity of biotic systems| but also to the lack of appropriate tools to measure regional biotic processes. These tools are now becoming available and with them a better understanding of terrestrial and atmospheric interactions. Even as these capabilities become a reality we must be realistic in recognizing that we have so far to go along the road to understanding that useful predictive capacity may elude us for a long time to come. What we now need to do is act on the recommendations that have been emerging over the past few years and develop a global program to document more precisely the distribution| structure| and quantity of the earth's biotic systems| their principal functional properties| and - most difficult of all - their changing nature. In order to do this we will have to: (1) perfect some of the emerging new tools for assessing these properties| (2) fill some of the gaps in our knowledge about the relevant processes| and (3) establish an international network of long-term observations and large-scale ecosystem manipulations. We have been aware of these needs and shortcomings for some time and we must move from plans to concerted international action. 3626,1991,3,4,BIOTECHNOLOGICAL ADVANCES IN BIOMASS ENERGY AND CHEMICAL PRODUCTION - IMPACTS ON WILDLIFE AND HABITAT,One promising application of biotechnology is in making the production of energy and chemical products from plants ("biomass") practical. Applications include new markets for crops and reduction of wastes by using field residues or "wastelands" as feedstocks in biomass energy production. In addition| engineered crops could synthesize complex compounds. However| conversion to widespread use of biomass could have undersirable impacts. For example| changes in cropping practices may reduce wildlife populations or disrupt food chains. Other negative impacts of an environmentally insensitive development might include increased release of CO2 (worsening global warming)| and production of wastes| either water| chemical or biological| that present disposal problems. Biotechnology applied to biomass and chemical production has the potential for aiding economic development while greatly improving environmental quality. Environmental concerns are expressed in this paper| in the belief that consideration of potential problems at the inception of a technology increases the likelihood that environmentally sound courses will be pursued. 3555,1991,2,3,BOREAL FOREST SENSITIVITY TO GLOBAL WARMING - IMPLICATIONS FOR FOREST MANAGEMENT IN WESTERN INTERIOR CANADA,Unmitigated global warming due to the enhanced greenhouse effect could have significant impacts on the boreal forest in interior western Canada. Increases in annual temperature of 3 to 7-degrees-C are projected for Alberta under a 2 x CO2 scenario by 2030-2050 A.D. Such an unprecedented rate of change has many short- and long-term implications for forest management and for industries. As the boreal forest is highly sensitive to climatic changes| foresters need to develop a set of safe strategies to minimize the negative impacts and maximize the benefits of these changes. 2143,1991,3,2,BUYING ENVIRONMENTAL INSURANCE - PROSPECTS FOR TRADING OF GLOBAL CLIMATE-PROTECTION SERVICES,In order to alleviate the threat of global climate change| coordinated international action is needed. This cooperation should include multilateral agreements and new economic initiatives to help implement measures that will slow the accumulation of carbon dioxide in the Earth's atmosphere due to tropical deforestation and fossil-fuel use. An international market in environmental services can help to safeguard the Earth's climate and foster economic development through a North-South transfer of financial resources. We suggest international carbon-emission offsets (ICEOs) as a means by which international markets| under a policy umbrella such as a multilateral climate-protection treaty| could trade carbon-saving services. Such a market would provide a currency for rewarding actions that reduce global carbon emissions| allowing carbon emitters to seek the least expensive ways to reduce emissions. This currency would transfer cash and/or debt relief from industrialized nations to developing nations| allowing the developing nations to profit from the use of clean energy technologies and the protection| rather than depletion| of tropical forests. 3567,1991,3,3,BUYING GREENHOUSE INSURANCE,There have been numerous proposals for immediate cutbacks in CO2 emissions. Proponents argue that sizable reductions are necessary as a hedge against unacceptably rapid changes in climate. This paper provides a decision tree analysis of the problem. We examine how the optimal hedging strategy might vary with: a) the damage potential associated with the continued buildup of greenhouse gases; b) the accuracy and timing of climate research; and| c) the prospects for new supply and conservation technologies. The analysis is from the perspective of a single country| the USA. Optimal hedging strategies need to be explored on a region-by-region basis. 3621,1991,2,3,CHANGES IN NUMBER OF DAYS EXCEEDING CERTAIN VALUES OF MAXIMUM AND MINIMUM TEMPERATURES,In large cities of Japan such as Tokyo| Osaka| Kyoto and others| the number of cold winter days and hot summer nights have considerably changed since the 1950s. This paper gives: (1) data showing observed changes of urban warming in these cities; (2) discussion concerning the method and the results of estimates on number of days exceeding or not reaching certain values of maximum and minimum temperatures from monthly mean temperatures; and (3) probable changes in these numbers in selected large cities of Japan in connection with predicted global warming due to an increase in atmospheric greenhouse gases. 3569,1991,2,4,CHLOROPHYLL-A DISTRIBUTION IN THE SOUTHERN BENGUELA| POSSIBLE EFFECTS OF GLOBAL WARMING ON PHYTOPLANKTON AND ITS IMPLICATIONS FOR PELAGIC FISH,A summary is given of available chlorophyll data and statistical relationships between chlorophyll and primary production off the south and west coast of South Africa. An attempt is made to quantify the extent of the 'productive' coastal area and to give an idea of its variation and the implications of this at higher trophic levels. We then speculate on the implications of regional global warming in this regard. Proposals for monitoring chlorophyll distributions are also discussed. 3616,1991,2,4,CLIMATE CHANGE AND ISOPRENE EMISSIONS FROM VEGETATION,A global model was developed for estimating spatial and temporal patterns in the emission of isoprene from vegetation under the current climate. Results were then used to evaluate potential emissions under doubled-CO2 climate scenarios. Current emissions were estimated on the basis of vegetation type| foliar biomass (derived from the satellite-generated Global Vegetation index)| and global databases for air temperature and photoperiod. The model had a monthly time step and the spatial resolution was 0.5 degrees latitude and longitude. Emissions under patterns of precipitation and temperature projected for a doubling of atmospheric CO2 were estimated based on predicted changes in the areal extent of different vegetation types| each having a specific rate of annual isoprene emissions. The global total for current emissions was 285 Tg. The calculated isoprene emissions under a doubled-CO2 climate were about 25% higher than current emissions due mainly to the expansion of tropical humid forests which had the highest annual emission rates. An increase in isoprene emissions would be likely to increase atmospheric concentrations of ozone and methane| which are important greenhouse gases| and thus act as a positive feedback to global warming. Detailed treatment of this question| however| will require incorporation of these emission surfaces into global atmospheric chemistry models. 3525,1991,3,2,CLIMATE CHANGE NEGOTIATIONS POLARIZE,After three sessions of the UN-sponsored Intergovernmental Negotiating Committee for a Framework Convention on Climate Change| global warming negotiations appear to have polarized around two key issues. Countries are divided over how strictly the treaty should control greenhouse gas emissions and how to share the hardship of emission controls in the most fair and equitable manner. The United States' "go slow" position has frustrated European efforts to create a convention with binding targets and timetables for reducing greenhouse gases (GHGs). Developing nations fear that the United States' refusal to control CO2 emissions signals a lack of commitment toward halting global warming and foreshadows future equity conflicts over financial and technical assistance to help them adopt "climate friendly" development paths. Nevertheless| early negotiating positions can be deceptive. The existence of many significant| low cost energy reforms indicates the existence of untapped bargaining space for overcoming these immediate deadlocks. However| these "no regrets" energy reforms are only the easy| first steps toward arresting climate disruption. Powerful and deeply entrenched social forces will resist an increasingly desperate need to dramatically reduce the global combustion of fossil fuels.
2140,1991,3,4,CLIMATE CHANGE PERCEPTIONS AND ENERGY-USE DECISIONS IN NORTHERN SWEDEN,Lay perceptions of global climate change were examined in the Swedish town of Umea. Interviews revealed that some residents believed temperatures were becoming warmer| but few perceived linkages between the threat of global climate change and energy use. The desire to reduce household expenditure motivated conservation measures more than concerns about environmental issues. The greenhouse effect was confused with the issue of stratospheric ozone depletion and reductions in the use of aerosol cans were judged to be appropriate policy responses to the threat of greenhouse warming. 3619,1991,2,4,CLIMATE| FORESTS| AND FIRE - A NORTH-AMERICAN PERSPECTIVE,The earth's climate may currently be undergoing a warming in response to the well documented accumulation of CO2 and other greenhouse gases. Changes in forestland areas and biomass are playing a role in the accumulation. This paper reviews and offers some observations on estimates of the role of forests in the carbon cycle. The temperate forests are roughly in carbon balance| with biomass growth equaling or exceeding losses. The tropical forests| by contrast| are a carbon source with forest area declining due primarily to land-use changes. A number of carbon-sequestering sources| such as wood construction and landfills| may be sequestering more carbon than is commonly assumed. Climate change can also affect forests. A number of mechanisms that influence forest growth and composition are discussed. In the absence of increased precipitation and/or a CO2 "fertilization" effect| warming is likely to diminish forest area and biomass. Forest burning is part of the natural cycle. During a burn| carbon is released through the post-burning period and typically involves carbon sequestering as the result of regeneration and vigorous growth. In an undisturbed natural system| a steady-state level of global forest biomass would be reached. Anthropogenic factors can upset the natural steady state. In a period of rapid climate transition| such as might accompany a global warming| forests are likely to lose vigor and thus be particularly susceptible to wildfire. 3603,1991,4,2,CLIMATOLOGY AND SOCIETY,The role of climate as a critical factor affecting the nature of the physical environment has been a traditional concern of geographers. Recently these concerns have been replaced by more urgent issues - atmospheric pollution| acid rain| global warming and ozone depletion. Decisions by the global society on how and at what level of well being human life should be organised are radically changing the gaseous character of the Earth's atmosphere. As a result| marked global warming will occur| and will have profound effects on societies across the world| some time during the next century. The ways in which the scientific study of climate - the field of climatology - may interact with society are examined| rather than considering the impact of climate itself on society. The data available are many and varied| and in their use a broad distinction can be drawn between the statistical and the physical approaches. Rather than a long list of the many fields of study that may be relevant| a limited number of types of such studies is presented. However| even with our improved understanding of climatology| the actual and probable future impacts of the world's climates on society are still to be unravelled. 3523,1991,3,3,CO-2 EMISSIONS REDUCTION BY PRICE DEREGULATION AND FOSSIL-FUEL TAXATION - A CASE-STUDY OF INDONESIA,As environmental issues| and the issue of global warming in particular| rise to the top of the international agenda| developing nations are faced with a major question: how to confront these environmental problems and simultaneously address a number of more pressing developmental imperatives? This paper tries to answer that question on a limited scale using Indonesia as a case study. The study indicates that by deregulating energy prices and imposing different levels of taxation on fossil fuels| Indonesia could reduce its CO2 emissions without considerably suppressing the growth of its economy. In the long run| however| these policies cannot cope with the inevitable rise in coal-use in Indonesia| due to constraints on domestic natural gas and oil resources. Limiting the growth of coal consumption in the future will require direct technological intervention in the supply and demand of energy and a shift in current energy export and import policies. 3529,1991,3,2,COAL-BED METHANE IN THE UK,British Coal measure their methane emissions at 0.8 +/- 0.2 million tonnes from UK coal mining in 1987. However| this figure cannot be verified until British Coal releases relevant data. Recently| the US Environmental Protection Agency has endorsed the use of an emission equation as a means of calculating methane emissions from coal mining. Methane emissions from coal mining rise to 1.19 - 2.21 Mt when this equation is applied to the UK. Both these estimates represent a lost resource and a major global warming effect due to methane's potency as a greenhouse gas. 2146,1991,4,5,COMPARISONS OF OBSERVED NORTHERN-HEMISPHERE SURFACE AIR-TEMPERATURE RECORDS,Comparisons are made between three climatic data sets consisting of Northern Hemispheric annual surface air temperature departures over the past 100 years. It is shown that despite the large values of linear cross-correlation between the data records| the longterm trends are significantly different according to the bootstrapping procedure. The confidence of relying on any particular data set for assessing global climate change statistics is thus questioned. 3629,1991,3,4,COST AND PERFORMANCE OF CO2 STORAGE IN FORESTRY PROJECTS,In order to include forestry projects in a possible CO2 emission reduction regime| and to compare the costs of individual projects or national programs| it is necessary to determine the rate of equivalency between carbon in fossil fuel emissions and carbon stored in different types of forestry projects. This paper presents a comprehensive and consistent methodology to account for the costs and carbon flows of different categories of forestry projects and describes the application of the methodology to a set of projects in Central America. Several estimates have been made to date of the overall potential for carbon storage through global reforestation and the costs of such efforts| based on global macroeconomic estimates and extrapolations from current forest-sector experience. However| there has yet to be a consistent analysis of the magnitude and cost of carbon savings by a "bottom-up" approach to sustainable forestry development This methodology is applied to a set of projects proposed in Costa Rica and other Central American countries under the Tropical Forest Action Plan| to estimate a sample set of national CO2 reduction cost curves. The costs of carbon savings in the forestry projects studied in Central America mostly fall between $5 and $13 ton-C1| depending on the type of project| the climate| and the opportunity cost of land. These projects also promise socio-economic benefits at the local level| provided they are adequately endowed with funding| training and institutional support. The total amount of CO2 storage potential is significant| about 100 million tons per country| but not enough to suggest that forestry can offset more than a few percent of global CO2 emissions from fossil fuel use. 3605,1991,4,4,COULD REDUCING FOSSIL-FUEL EMISSIONS CAUSE GLOBAL WARMING,WHEN fossil fuel is burned| both carbon dioxide and sulphur dioxide are added to the atmosphere. The former should cause warming of the lower atmosphere by enhancing the greenhouse effect| whereas the latter| by producing sulphate aerosols| may cause a cooling effect. The possibility that these two processes could offset each other was suggested many years ago (see| for example| ref. 1)| but during most of the intervening period| attention has focused on the greenhouse effect. Interest in tropospheric aerosols has| however| recently been rekindled by the realization that they may influence climate| not only through clear-sky radiative effects 2-5| but also by modifying cloud albedo 6-8. Here I examine the sensitivity of the climate system to simultaneous changes in SO2 and CO2 emissions| as might occur if controls were imposed on fossil-fuel use. Over the next 10-30 years| it is conceivable that the increased radiative forcing due to SO2 concentration changes could more than offset reductions in radiative forcing due to reduced CO2 emissions. 2167,1991,3,4,COUNTERMEASURES FOR MITIGATING THE EFFECTS OF GLOBAL ENVIRONMENT CHANGES,Increased concern over the effects of global climate change and depletion of the ozone layer has resulted in support for the Global Change Research Program. Research to understand Earth system processes is critical| but it falls short of providing ways of mitigating the effects of change. Options and alternatives need to be developed. Space-based concepts for environmental countermeasures should be considered in addition to Earth-based actions. Definition| analysis| demonstration and preparation of mitigation technology provide a basis for policy response if global change consequences are severe. 2148,1991,4,4,CRYOSPHERIC PRODUCTS FROM THE DMSP-SSM .1. STATUS AND RESEARCH APPLICATIONS,The DMSP Special Sensor Microwave Imager (SSM/I) was launched on 19 June 1987. This first operational passive microwave radiometer operates at four wavelengths (0.35-1.55 cm) with vertical and horizontal polarization for three of the channels. The orbit provides global coverage except for a small polar gap and 12 hour repeat coverage in high latitudes. A Cryospheric Data Management System (CDMS) for snow and ice products developed by the NASA Ocean Data System (NODS) and the National Snow and Ice Data Center (NSIDC) for NASA Polar Oceans Programs extracts polar SSM/I data and makes them available in suitable formats for scientific users. The design of the CDMS at NSIDC has evolved since the initial planning in 1984 to one relying on CD-ROM technology for data distribution. The SSM/I data| and the earlier 7-year SMMR data (re-binned to the SSM/I grid)| are available as brightness temperatures averaged daily for each channel/polarization in a polar stereographic 25 km grid for both polar regions and as gridded 3-day average total sea ice concentrations and multiyear ice fractions based on the NASA Team algorithm. The availability of a passive microwave record of sea ice parameters since 1978 in a directly comparable format greatly facilitates their research use. The polar regions are of considerable importance in studies of global climate change in view of snow and ice/albedo feedback processes that contribute to the high latitude amplification of such changes. Related climate-cryosphere research includes studies to validate the algorithm employed to prepare the ice products| on ice/climate processes| and on temporal trends in sea ice. 3570,1991,4,4,DETECTION OF GLOBAL WARMING THROUGH SPATIAL TEMPERATURE-VARIATIONS BELOW THE EARTH SURFACE,The propagation of temperature disturbances down the earth is analyzed in various degrees of mathematical complexity. Exact analytical solutions as they are expected under conditions of global warming trends are given| with the most general case reduced to the solution of an integral equation. The solution of this equation permits to obtain the past trend in the surface temperature by a spatial measurement of the temperature below the earth surface at a fixed time. Analysis of the results may be the best indicator to resolve the controversy whether global warming is real. 3582,1991,4,4,DETERMINANTS OF PLANT-DISTRIBUTION - EVIDENCE FROM PINE INVASIONS,The question of which factors limit the occurrence of a plant species to a particular site is addressed by considering 53 cases in which the distribution of pines (Pinus species; Pinaceae) has changed in the last century. We consider expansions of pines in and adjacent to their natural ranges in the Northern Hemisphere and the spread from sites of introduction in the Southern Hemisphere well outside the contemporary range of pines. We first consider a neutral hypothesis (with respect to climate or biological interactions as determinants of invasion): invasion simply requires that a species is present in sufficient numbers| with sufficient propagules over sufficient time to invade. We then explore the relative importance of climatic changes. disturbance| competition (including competition between seedlings and herbaceous plants during early establishment)| herbivory| pathogens| and other agents that might influence pine membership in communities. Determinants of susceptibility to invasion often interact in a complex fashion. Environmental stresses created by moisture and temperature appear to exercise primary control on invasibility at xeric and high-elevation sites| respectively| but play a smaller role at intermediate locations. At these sites| range limits are determined principally by interactions between pine seedlings and the resident biota in adjacent communities. This suggests that the effects of predicted global warming on the distribution of pines are unlikely to be simple functions of temperature or precipitation. except at climatic extremes. Pine invasions are most prevalent where there is limited competition in the regeneration niche and occur more easily in habitats where the dominant growth form is most different from that of pines| namely| in grasslands. The disturbance regime in the receiving habitat is important and interacts directly and indirectly with the "inherent" susceptibility to invasion. Severe disturbances may initiate pine invasions at any latitude| but are essential for reducing the cover of vigorous plant growth (and hence competition in the regeneration niche) in tropical and near-tropical regions. Contemporary practices such as deforestation and increased grazing pressure and those practices leading to accelerated erosion| modified fire regimes| and climate amelioration essentially duplicate ice-age stresses and disturbances that shaped plant communities in the Holocene. The fundamental role of biotic factors (either direct or indirect) in regulating the distribution of pines is discussed with reference to aspects of land husbandry including the management of biological invasions. 3598,1991,5,4,DEVELOPMENT OF EARLY EOCENE WARM CLIMATES| AS INFERRED FROM CLAY MINERAL VARIATIONS IN OCEANIC SEDIMENTS,Late Paleocene to middle Eocene clay mineral associations have been considered at fifteen locations from the Atlantic Ocean and the adjacent sector of the Southern Ocean| and compared to the results of previous investigations. Globally warm climates and alternating wet and arid seasons are deduced from the widespread abundance of pedogenic smectite at every location. Near the Paleocene-Eocene boundary| enhanced humidity at high latitudes and in continental hinterlands is indicated by more abundant kaolinite| while in coastal areas from low and middle latitudes increased aridity resulted in more abundant palygorskite (and/or sepiolite). Concomitant increases of kaolinite and fibrous clays are correlated with lower delta-O-18 of benthic and planktonic foraminifers in most oceanic areas| indicating that warmer conditions were associated with enhanced evaporation at low to middle latitudes| and increased precipitation at high latitudes. This is consistent with an improvement of meridional transfers of energy| which probably contributed to the compensation of the equator to pole thermal disequilibrium increased by the global warming. During the middle Eocene| both kaolinite and palygorskite contents decreased at most southern locations| coeval with higher delta-O-18. Inferred cooling and reduced thermal exchanges especially characterized the southern high latitudes| and possibly resulted from plate tectonic evolution. 3604,1991,2,4,DROUGHT - OPPORTUNITIES FOR IMPACT MITIGATION,Drought is an ancient natural hazard that has probably killed more people than any other. It is difficult to mark the start and end of drought because the moisture deficit develops slowly over weeks| months| or years. Atmospheric scientists can neither forecast nor control drought. Drought mitigation must focus on reducing the underlying physical and social vulnerability. Short-term adjustments do not yield a lasting adaptation to drought. Some argue that repetitive food aid may worsen long-term food-production problems and land degradation by deferring more fundamental adjustments. Decisionmakers need better information and a broader range of adjustment options in order to reduce drought vulnerability. A linking of global warming/climate change studies with drought studies can yield insights into how societies might deal with climate change and help define the potential for future drought. (Ed.) 3625,1991,3,3,EFFECT OF ENCAPSULATED CALCIUM CARBIDE ON DINITROGEN| NITROUS-OXIDE| METHANE| AND CARBON-DIOXIDE EMISSIONS FROM FLOODED RICE,The efficiency of N use in flooded rice is usually low| chiefly due to gaseous losses. Emission of CH4| a gas implicated in global warming| can also be substantial in flooded rice. In a greenhouse study| the nitrification inhibitor encapsulated calcium carbide (a slow-release source of acetylene) was added with 75| 150| and 225 mg of 75 atom % N-15 urea-N to flooded pots containing 18-day-old rice (Oryza sativa L.) plants. Urea treatments without calcium carbide were included as controls. After the application of encapsulated calcium carbide| 3.6-mu-g N2| 12.4-mu-g N2O-N| and 3.6 mg CH4 were emitted per pot in 30 days. Without calcium carbide| 3.0 mg N2| 22.8-mu-g N2O-N| and 39.0 mg CH4 per pot were emitted during the same period. The rate of N added had a positive effect on N2 and N2O emissions| but the effect on CH4 emissions varied with time. Carbon dioxide emissions were lower with encapsulated calcium carbide than without. The use of encapsulated calcium carbide appears effective in eliminating N2 losses| and in minimizing emissions of the "greenhouse gases" N2O and CH4 in flooded rice. 3558,1991,2,4,EFFECTS OF CLIMATE ON REPRODUCTION IN THE EUROPEAN WILD RABBIT (ORYCTOLAGUS-CUNICULUS),Reproduction in a population of European wild rabbits occupying parkland habitat in East Anglia showed an annual seasonality in terms of numbers of emergent young| male testes size and an index of female oestrous status. Weather conditions showed marked variation over the four-year study period with significantly higher minimum ground temperatures and hours of daily sunshine| and less snowfall recorded during the second two years. Parallel shifts in reproductive seasonality were found with male testes size peaking in January and February as opposed to May and April| first female oestrus recorded one month earlier (January compared to February)| and young emerging over an average of 5.5 instead of 4.5 months each year and their first appearance above ground advanced by two months from April to February. Mean annual productivity increased from 7.2 and 6.1 emergent young per female| to 10.1 and 9.1 over the four years| while the number of adults present in the population at the start of the breeding season increased from 22 to 45| with females always outnumbering males. The usefulness is demonstrated of a non-invasive index of vulva appearance| and morphometric measures of testes to determine female oestrous status and estimates of male testicular weight in wild populations. The reported changes in reproduction are probably mediated through the influence of climatic variables on the quality or quantity of food available to the rabbits. These data demonstrate the possible effects of predicted global warming on productivity in the rabbit and highlight the major influence of climate on reproductive seasonality in this important pest species. 3581,1991,3,4,ENERGY ANALYSIS OF RENEWABLE ENERGY-SOURCES,This paper examines the application of energy analysis to the assessment of renewable energy sources. The basic features| terms| conventions and methods of energy analysis which were established during the 1970s are introduced and the value of energy analysis as a means of evaluating new energy technologies is explained in relation to current concern about resource depletion and global warming. Additionally| the way in which energy analysis can complement conventional economic evaluation is discussed. An extensive summary of results from previous energy analysis studies of renewable energy sources is presented and essential improvements in energy analysis databases to enable progress with new studies are described. 3516,1991,3,4,ENERGY AND TECHNOLOGY OPTIONS FOR CO2 EMISSION REDUCTION TOWARDS SYMBIOTIC USE OF NUCLEAR-ENERGY AND FOSSIL-FUELS,The potential of CO2 emission reduction is analyzed by the MARKAL model for the Japanese energy system in the time horizon 1985 approximately 2030| taking into account such reduction measures as energy conservation| fuel switching| and technology substitution. Among them| nuclear energy utilization is found to have a large CO2 reduction potential| i.e. from 10% reduction of the total emission in 1990 to the levels of 16%| 21% and 42% in years 2000| 2010 and 2030| respectively| through electric power generation and process heat application. 2141,1991,3,4,ENERGY EFFICIENCY - A NO REGRETS RESPONSE TO GLOBAL CLIMATE CHANGE FOR WASHINGTON-STATE,Future climate changes pose a difficult challenge for public policymaking| in part due to uncertainty of predictions| especially on the scale of countries or regions. Nevertheless| it is possible to estimate the costs and potential benefits of attempting to reduce climate change. The authors| from the Washington State Energy Office| review international| national| and state energy strategies. They emphasize that we will "not regret" policies designed to improve energy-use efficiency| no matter how unknown the future| because of resultant cost savings| energy savings| and less reliance on fossil fuels-hence the reduction of the major forces of climate change. 3572,1991,3,3,ENVIRONMENTAL IMPACTS OF ENERGY FACILITIES - FUEL-CELL TECHNOLOGY COMPARED WITH COAL AND CONVENTIONAL GAS TECHNOLOGY,We compare the environmental side effects of power plants based on fuel cell technology with the side effects of conventional electric power plants based on coal and natural gas. The environmental impact of a solid oxide fuel cell (SOFC) plant is very much less than that of a coal-fired plant (a factor of 1/300 for air pollution and a factor of 1/5 for water pollution). Compared with a conventional gas plant| impact is reduced by between 50 and 98%. Damage to cultural monuments and buildings is negligible from a fuel cell plant. Socioeconomic negative impacts are reduced by about 30% relative to conventional gas plants (aesthetics and noise) whereas employment is unaltered. Impact on health and safety is greatly reduced compared with that from coal-fired plants and is about 70% of that from conventional gas plants. Preliminary results suggest that society's willingness to pay (WTP) for clean air| and thereby better health| matches the cost of installing emission-reducing equipment on conventional power plants. There is probably an additional WTP for other benefits (e.g.| decreased risk of global warming). Thus| the utility of very small emissions| lower CO2 discharges| and other benefits from SOFC generators may compensate for the increased cost incurred in producing electricity by SOFC generators. 3546,1991,2,3,ENVIRONMENTAL PRODUCTIVITY INDEXES AND PRODUCTIVITY FOR OPUNTIA-FICUS-INDICA UNDER CURRENT AND ELEVATED ATMOSPHERIC CO2 LEVELS,The productivity of the prickly-pear cactus Opuntia ficus-indica| which is cultivated worldwide for its fruits and stem segments| was predicted based on the responses of its net CO2 uptake to soil water status| air temperature and photosynthetic photon flux density (PPFD). Each of these environmental factors was represented by an index with a maximum value of unity when that factor was not limiting net CO2 uptake over a 24-h period. The water index| the temperature index| and the PPFD index were determined for 87 sites in the contiguous United States using data from 189 weather stations and for 148 sites worldwide using data from 1464 weather stations. The product of these three indices| the environmental productivity index (EPI)| was used to predict the productivity of O. ficus-indica under current climatic conditions and under those accompanying a possible increase in the atmospheric CO2 level to 650-mu-mol mol-1. Sites with temperatures always above -10-degrees-C and hence suitable for prickly-pear cultivation numbered 37 in the United States and 110 worldwide; such sites increased by 43 and 5%| respectively| for the global warming accompanying the elevated CO2. Productivity of O. ficus-indica was at least 15 tonnes dry weight hectare-1 year-1| comparable to that of many agronomic crops| for 20 sites with temperatures always above -10-degrees-C in the contiguous United States and for 12 such sites worldwide under current climatic conditions; such sites increased by 85 and 117%| respectively| under the elevated CO2 condition| mainly because of direct effects of the atmospheric CO2 level on net CO2 uptake. In summary| simulations based on EPI indicate that O. ficus-indica may presently be advantageously cultivated over a substantial fraction of the earth's surface| such regions increasing markedly with a future doubling in atmospheric CO2 levels. 2166,1991,5,4,EVOLVING PLIOCENE PLEISTOCENE CLIMATE - A NORTH PACIFIC PERSPECTIVE,Siliceous microfauna in sediments from North Pacific Deep Sea Drilling Project sites record the response of the regional surface and near-surface waters to global climate change over the past 3.0 Ma. During the Late Pliocene (2.7-3.0 Ma)| the northern subtropical and subpolar Pacific experienced warmer climate conditions than those of today. The first predominant polar assemblage maximum occurs in the North Pacific at approximately 2.45 Ma signifying this region's response to the initiation of significant northern hemisphere glaciation. North Pacific faunal data show that Late Pliocene (1.8-2.5 Ma) glacial maxima were only about half to two-thirds as severe as those which occurred during the Late Pleistocene. Low faunal assemblage variability during a 200 ka interval in the latest Pliocene (1.6-1.82 Ma) in the North Pacific indicates minimal variations in the surface water properties and climate conditions most like those which existed just prior to 2.5 Ma. A distinct change in faunal assemblage registered in sediments from Site 580 between 1.2 and 1.3 Ma marks the first cooling in the North Pacific comparable in intensity to those of the Late Pleistocene. Since approximately 1.26 Ma| high amplitude| high frequency variations in the North Pacific polar assemblage have continued to occur| providing further evidence that the interglacial/glacial extremes that characterize the Late Pleistocene have persisted since this time. The frequency distribution of North Pacific winter sea-surface temperature time series for the Late Pliocene and Early Pleistocene includes major concentrations of variance (power) centered at a frequency corresponding to a 41 ka period| with variance dominance of the temperature time series for the last 800 ka shifting to lower frequencies (approximately 110 ka period). 3542,1991,2,4,FIRE AND DROUGHT EXPERIMENTS IN NORTHERN WETLANDS - A CLIMATE CHANGE ANALOG,Drought and fire| which may increase in frequency and severity because of global warming| were simulated in mid-boreal wetlands by transplanting soil blocks upslope to a lower water table and by prescribed burns. In the 2 years after treatments were applied to seasonally flooded vegetation zones in the Peace-Athabasca Delta| Alberta| the drought treatment did not significantly change stem density and height of the dominant hygrophytes Calamagrostis canadensis and Carex atherodes. Dicotyledonous species' density and richness increased 3- to 36-fold on soil blocks moved upslope to the driest vegetation zone relative to unmoved soil blocks. The percent cover of native dicotyledonous species was unaffected but that of xerophytic Eurasian species| Sonchus arvensis and Cirsium arvense| increased 5- to 13-fold after drought treatment. Fire| particularly the deepest burn| reduced graminoid density and height up to 90%. Dicotyledon density| but not richness| was generally higher after fire. Plant cover was unaffected by fire but Eurasian species' cover was still 3- to 15-fold greater than that of native species. Seasonally flooded vegetation zones will likely be shifted from flood-driven dynamics with cool and moist environmental conditions towards drought- and fire-driven dynamics with warmer and drier conditions. It is hypothesized that| under these climate change conditions| Eurasian species might dominate early successional communities in mid-boreal wetlands. 2159,1991,2,4,FISH AND FISHERIES ECOLOGY,My paper on fish and fisheries ecology is offered to demonstrate a rich blending of applied and fundamental ecology| achieved by the intersections among fishery science| ichthyology| and ecology. The example| while specific| parallels practices and opportunities available in other areas of applied ecology. The emergence of fish and fisheries ecology as a discipline is evidenced by such recent textbooks as Fisheries ecology by Pitcher and Hart (1982) and Ecology of teleost fishes by Wootton (1990). The ecology relevant to fish and fisheries includes not only marine and freshwater ecology|oceanography| and limnology| but also terrestrial study. Early work in fish and fisheries ecology came from Stephen A. Forbes > 100 yr ago in his books On some interactions of organisms (Forbes 1880) and The lake as a microcosm (Forbes 1887). These constitute one of the earliest conceptualizations of an ecosystem. By 1932 E. S. Russell concluded that fishery research was a study in marine ecology. I give examples of applications from six different categories of ecology. (1) Physiological ecology: The F. E. J. Fry school of fish physiology developed the concepts of temperature as a lethal|controlling and directive factor. More than 40 yr later| this knowledge is being combined with G. E. Hutchinson's concept of an n-dimensional niche to analyze potential influences of global climate warming on fishes. (2) Behavioral ecology: A. D. Hasler and students formulated and tested the hypothesis of olfactory imprinting as the mechanism by which Pacific salmon "home" to their natal spawning streams. Applications to reestablish salmon runs are as important to Hasler as the original scientific discovery; this is evident in his proposed "Salmon for Peace"for the river bounding USSR and China. (3) Population ecology: The realization that reproductive success of fishes depends more on larval mortality than on egg production emerged from the ideas of J. Hjort (1914). To this day inconsistencies between recruitment and reproductive stock size impart uncertainty into fishery management| while the search for explanatory mechanisms attracts the curious mind. (4) Community ecology: Species interactions are the grist of community ecology; predation and fishing are a natural for comparative study and application. Also| consumption by fish can control the dynamics of planktonic and benthic animal/plant communities; thus| apparent water quality of lakes depends on the consumer community as well as on nutrient inputs. (5) Ecosystem ecology: D.S. Rawson grouped external| abiotic influences on lakes into climatic| edaphic| and morphometric factors. The morphoedaphic index (Ryder 1965) predicts fish yields from this base| providing fish managers with a useful approximation and ecologists with a conceptual base for synthesis of production processes. (6) Landscape ecology: Regional ecology often incorporates land-water boundaries into the way ecological systems work. Application of island biogeography to lakes| as islands| has allowed predictions of fish assemblages for use by managers. Also| the extent and connectedness of lake and ocean "landscapes" offer insight into contrasts between marine and freshwater fishery research and management. In conclusion| the ecotone between academic and applied ecology seems an ideal place from which to advance both applied ecology and ecology in general. 2156,1991,3,3,FUEL ETHANOL FROM CELLULOSIC BIOMASS,Ethanol produced from cellulosic biomass is examined as a large-scale transportation fuel. Desirable features include ethanol's fuel properties as well as benefits with respect to urban air quality| global climate change| balance of trade| and energy security. Energy balance| feed-stock supply| and environmental impact considerations are not seen as significant barriers to the widespread use of fuel ethanol derived from cellulosic biomass. Conversion economics is the key obstacle to be overcome. In light of past progress and future prospects for research-driven improvements| a cost-competitive process appears possible in a decade. 3566,1991,3,4,GETTING STARTED - NO-REGRETS STRATEGIES FOR REDUCING GREENHOUSE GAS EMISSIONS,An integrated approach for choosing among energy supply- and demand-side measures shows that| compared to business-as-usual demand patterns| global greenhouse-gas emissions can be reduced well below current levels with net economic benefits to society. Given these findings| a 'wait-and-see' stance towards new initiatives in energy and environmental policy is not economically justifiable. Achieving significant emissions reductions| however| will require commitments to policies aimed at enabling energy markets to function more efficiently and supporting legislation where market forces do not suffice. 3512,1991,2,2,GLOBAL ATMOSPHERIC CHANGES,Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health| because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels| global warming also may result in increases in air pollutants| acid deposition| and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health| this review emphasizes the processes that are responsible for the greenhouse effect| air pollution| acid deposition| and increased exposure to UV radiation. 3556,1991,2,4,GLOBAL CHANGE AND TERRESTRIAL HYDROLOGY - A REVIEW,This paper reviews the role of terrestrial hydrology in determining the coupling between the surface and atmosphere. Present experience with interactive numerical simulation is discussed and approaches to the inclusion of land hydrology in global climate models are considered. At present| a wide range of answers as to expected changes in surface hydrology is given by nominally similar models. Studies of the effects of tropical deforestation and global warming illustrate this point. 2151,1991,3,6,GLOBAL CLIMATE CHANGE,This paper reviews the validity of the greehouse warning theory| its possible impact on the automotive industry| and what could be done. Currently there is very limited evidence that man's activity has caused global warming. Mathematical models of the earth's heat balance predict warming and associated climate changes| but their predictions have not been validated. Concern over possible warming has led to several evaluations of feasible CO2 control measures. Although cars and trucks contribute only a small fraction of the CO2 buildup| the automotive industry may be expected to reduce its share of the atmospheric CO2 loading if controls become necessary. Methods to reduce automotive CO2 emissions| including alternative fuels such as methanol| natural gas| and electricity| are discussed. Also| control of the other greenhouse gases| which may currently contribute about 45 percent of the greenhouse warming| is considered.
2138,1991,3,4,GLOBAL CLIMATE CHANGE - IMPLICATIONS FOR THAILAND ENERGY-SYSTEMS,An energy/environmental model has been developed to estimate Thailand's energy consumption and CO2 emissions through the end of the National Tenth Plan (year 2011). The projection suggests that fossil-fuel consumption| not deforestation| will be the major source of emissions during 1990-2011. By the year 2011| energy-efficiency improvement measures could bring about a 14% reduction of CO2 emissions. Any reduction beyond this level would require switches of fuel mix in the power| transportation| and industrial sectors. Fuel shifts in the power sector alone could cut emissions by up to 20% to 30%. In the longer run| Thailand should consider adopting unconventional sources of energy| as well as make use of reforestation policy to absorb future CO2 emissions. 2131,1991,2,4,GLOBAL CLIMATE CHANGE AND INFECTIOUS-DISEASES,The effects of global climate change on infectious diseases are hypothetical until more is known about the degree of change in temperature and humidity that will occur. Diseases most likely to increase in their distribution and severity have three-factor (agent| vector| and human being) and four-factor (plus vertebrate reservoir host) ecology. Aedes aegypti and Aedes albopictus mosquitoes may move northward and have more rapid metamorphosis with global warming. These mosquitoes transmit dengue virus| and Aedes aegypti transmits yellow fever virus. The faster metamorphosis and a shorter extrinsic incubation of dengue and yellow fever viruses could lead to epidemics in North America. Vibrio cholerae is harbored persistently in the estuaries of the U.S. Gulf Coast. Over the past 200 years| cholera has become pandemic seven times with spread from Asia to Europe| Africa| and North America. Global warming may lead to changes in water ecology that could enhance similar spread of cholera in North America. Some other infectious diseases such as LaCrosse encephalitis and Lyme disease are caused by agents closely dependent on the integrity of their environment. These diseases may become less prominent with global warming because of anticipated modification of their habitats. Ecological studies will help us to understand more fully the possible consequences of global warming. New and more effective methods for control of vectors will be needed.
3584,1991,3,2,GLOBAL WARMING - CAUSES| CONSEQUENCES| AND SOME IMPLICATIONS FOR LATIN-AMERICA,The scientific evidence is clear in showing that the accumulation of greenhouse gases in the atmosphere| which trap heat that otherwise would be lost to space| will cause a rise in the planetary temperature. It has also been suggested that this warming is already occurring. Anthropogenic emissions of these greenhouse gases since the industrial revolution have altered the composition of the atmosphere| and may be responsible for the observed warming of 0.5-1.0-degrees-C in the mean temperature of the planet| and a rise in sea level of about 10 cm. Although this is primarily a result of fossil fuel use by developed countries of the northern hemisphere| deforestation in tropical countries could be an important source of emissions as well. The consequences of this continuous warming| if no preventive actions are taken| will be catastrophic. Latin American countries could be affected directly and indirectly| and the social| political| and economic implications are serious. Lowering the use of fossil fuels and stopping tropical deforestation are the best practical solutions to global warmining. International cooperation is necessary to achieve these goals| taking into account the development needs of Latin American and other Third World countries. Development projects that promote sustainable uses of tropical forests could benefit Latin American countries while at the same time contribute to the solution to global warming. It is imperative that the problem of global warming be taken seriously| and that preventive measures be taken immediately.
3518,1991,4,2,GLOBAL WARMING - EVIDENCE FOR ASYMMETRIC DIURNAL TEMPERATURE-CHANGE,Analyses of the year-month mean maximum and minimum surface thermometric record have now been updated and expanded to cover three large countries in the Northern Hemisphere (the contiguous United States| the Soviet Union| and the People's Republic of China). They indicate that most of the warming which has occurred in these regions over the past four decades can be attributed to an increase of mean minimum (mostly nighttime) temperatures. Mean maximum (mostly daytime) temperatures display little or no warming. In the USA and the USSR (no access to data in China) similar characteristics are also reflected in the changes of extreme seasonal temperatures| e.g.| increase of extreme minimum temperatures and little or no change in extreme maximum temperatures. The continuation of increasing minimum temperatures and little overall change of the maximum leads to a decrease of the mean (and extreme) temperature range| an important measure of climate variability. The cause(s) of the asymmetric diurnal changes are uncertain| but there is some evidence to suggest that changes in cloud cover plays a direct role (where increases in cloudiness result in reduced maximum and higher minimum temperatures). Regardless of the exact cause(s)| these results imply that either: (1) climate model projections considering the expected change in the diurnal temperature range with increased levels of the greenhouse gases are underestimating (overestimating) the rise of the daily minimum (maximum) relative to the maximum (minimum)| or (2) the observed warming in a considerable portion of the Northern Hemisphere landmass is significantly affected by factors unrelated to an enhanced anthropogenically-induced greenhouse effect. 3527,1991,2,6,GLOBAL WARMING - WHAT DOES THE SCIENCE TELL US,Computer models predict that clear signs of the greenhouse effect should have appeared as a consequence of increases in greenhouse gases| equivalent to a 50% increase in carbon dioxide in the last 100 years. The predictions are contradicted by the climate record in nearly every important respect. Contrary to the models: (1) the Northern Hemisphere has not warmed more than the Southern Hemisphere| (2) high latitudes have not warmed more than low latitudes| and (3) the U.S. has not shown the predicted warming trend| although this is the largest area in the world for which well-distributed| reliable records are available. Finally| all of the computations of the greenhouse effect show an accelerating increase in temperature in the 1980s| reflecting the rapid increase in greenhouse gases in recent years. However| measurements from orbiting satellites with a precision of 0.01-degrees-C show no trend to higher temperatures in the 1980s.
2137,1991,3,3,GLOBAL WARMING AND CLEAN ELECTRICITY,The possibility of global climate change due to the emission of carbon dioxide and other greenhouse gases poses dangers of a magnitude which is imprecisely known but may be very large. The problem can be ameliorated by reducing fossil fuel consumption through conservation and expanded use of nuclear and solar power. In particular| major reductions can be achieved if fossil fuels are replaced in electricity generation and if electricity assumes a larger role in the overall energy economy.
3520,1991,2,4,GLOBAL WARMING AND CLIMATE CHANGE IN MEXICO,Climate models suggest that global warming could bring warmer| drier conditions to Mexico. Although precipitation increases are projected by some models| in most cases they do not compensate for increases in potential evaporation. Thus| soil moisture and water availability may decrease over much of Mexico with serious consequences for rainfed and irrigated agriculture| urban and industrial water supplies| hydropower and ecosystems. However| the assessment of global warming impacts in Mexico is an uncertain task because the projections of different models vary widely| particularly for precipitation| and because they perform poorly in reproducing the observed climate of Mexico. 3514,1991,4,3,GLOBAL WARMING AND ELECTRIC-POWER GENERATION - WHAT IS THE CONNECTION,At present there is tremendous public interest in the global environment and the public scrutiny of industrial activities vis-a-vis their environmental impact. Large quantities of carbon dioxide are emitted to the atmosphere by many sources| both natural and man-made. Electric power generation by any fossil fuel burning produces carbon dioxide. In order to better understand the greenhouse problem| this paper discusses the quantity of carbon dioxide produced; where does it go and what impact does it have? This information may better prepare the electric utilities to address future public concerns and the related regulatory pressure regarding the carbon dioxide proliferation and the global warming. 3547,1991,2,4,GLOBAL WARMING AND REGIONAL RAINFALL - THE DIFFERENCE BETWEEN AVERAGE AND HIGH-INTENSITY RAINFALLS,Comparison of rainfall during cold and warm periods within instrumental records has been useful in developing quantitative climate scenarios in the face of prospective global warming. In south-eastern Australia| it is known that a warm period in the Southern Hemisphere in the latter part of this century coincided with greater rainfall| especially during summer months. In this study| based on daily rainfall data from 17 stations with longest record lengths on the Southern Tablelands| Australia| it is observed that high intensity rainfall does not necessarily follow the same pattern. In fact| the difference between rainfall in a warm and wet and a cold and dry period could decrease as the critical rainfall intensity increases. 3630,1991,2,4,GLOBAL WARMING AND THE INSURANCE INDUSTRY,The international insurance industry has had to deal with major increases in economic losses caused by natural and/or human-induced catastrophes over the last few decades. This article outlines how global warming is expected to increase such losses even further| and the consequences that this will have on the insurance industry. It examines the options for insuring against such risks and concludes that speedy political decisions are needed to minimize and mitigate the catastrophes that will occur if global warming is not soon brought under control. 3571,1991,4,5,GLOBAL WARMING AS A MANIFESTATION OF A RANDOM-WALK,Global and hemispheric series of surface temperature anomalies are examined in an attempt to isolate any specific features of the structure of the series that might contribute to the global warming of about 0.5-degrees-C which has been observed over the past 100 years. It is found that there are no significant differences between the means of the positive and negative values of the changes in temperature from one year to the next; neither do the relative frequencies of the positive and negative values differ from the frequencies that would be expected by chance with a probability near 0.5. If the interannual changes are regarded as changes of unit magnitude and plotted in a Cartesian frame of reference with time measured along the x axis and yearly temperature differences along the y axis| the resulting path closely resembles the kind of random walk that occurs during a coin-tossing game. We hypothesize that the global and hemispheric temperature series are the result of a Markov process. The climate system is subjected to various forms of random impulses. It is argued that the system fails to return to its former state after reacting to an impulse but tends to adjust to a new state of equilibrium as prescribed by the shock. This happens because a net positive feedback accompanies each shock and slightly alters the environmental state. 2150,1991,3,3,GLOBAL WHAT - CONTROL POSSIBILITIES OF CO2 AND OTHER GREENHOUSE GASES,Global what? is a frequent response by those who first hear of the potential for global warming| global climate change| and global catastrophe| potentially brought on by excessive greenhouse gases in the upper atmosphere. The principal greenhouse gas| CO2| is joined by methane| N2O| and other trace gases in absorbing infrared radiation| which would otherwise escape into space| a process thought to be responsible for gradual increase in temperature that will melt ice caps and raise ocean levels. This paper discusses control possibilities that could be considered once there is agreement that CO2 must be controlled. Many of the responses to the energy crisis of 1974 are applicable for CO2 control. A variety of technologies| energy sources| and ideas are offered that| in combination| could be the basis for a global energy policy. Conversion and replacement of coal| oil| and eventually natural gas fired electric power plants with other energy sources such as nuclear| solar| wind| tidal| and geothermal| could significantly reduce CO2 emissions. There are| however| no good alternatives to fossil fuels used in transportation that significantly reduce CO2 emissions. Of all the fossil fuels| natural gas has the least CO2 production. Electric vehicles and hydrogen-fueled engines are future possibilities| but the electricity for the electric cars and for making hydrogen must be from nonfossil fuel driven generators. Conservation| efficiency| and tax incentives are other parts of a control strategy| once the amount of control considered necessary is established. Renewed interest in nonfossil fuel energy sources and their research and development is obviously needed. 3610,1991,2,3,GREENHOUSE WARMING MAY MODERATE BRITISH STORMINESS,An analysis of data pertaining to the period 1861-1986 reveals that (1) a 1-degrees-C rise in the mean annual air temperature of the British Isles has historically been associated with a 35% drop in the percentage of days that the United Kingdom has experienced cyclonic flow| and (2) a 2-degrees-C increase in the mean annual air temperature over the sea to the north has typically been matched by a 60% drop in the percentage of days that the Isles have experienced cyclonic flow originating from that source region. These findings raise significant questions about the oft-reported claim that CO2-induced global warming will lead to an increase in world storminess. 3622,1991,2,2,GREENHOUSE-EFFECT AND COASTAL WETLAND POLICY - HOW AMERICANS COULD ABANDON AN AREA THE SIZE OF MASSACHUSETTS AT MINIMUM COST,Climatologists generally expect an anthropogenic global warming that could raise sea level 30-150 cm in the next century and more thereafter. One of the impacts would be the loss of coastal wetlands. Although the inundation of adjacent dryland would enable new wetlands to form| much of this land is or will soon be developed. If developed areas are protected| wetlands will be squeezed between an advancing sea and the land being protected| which has already happened in China and the Netherlands| where people have built dikes for centuries. Unlike those countries| the United States has enough land to accommodate the landward migration of wetlands; but governments lack the funds to purchase all the coastal lowlands that might inundated and the legal authority to prohibit their development. We propose a third approach: allowing property owners to use coastal lowlands today as they choose| but setting up a legal mechanism to ensure that the land is abandoned if and when sea level rises enough to inundate it. Although compensation may be required| this approach would cost less than 1% as much as purchasing the land| and would be (1) economically efficient by enabling real estate markets to incorporate expectations of future sea level rise; (2) constitutional by compensating property owners; and (3) politically feasible by pleasing people who care about the long-term fate of the coastal environment without disturbing people who either are unconcerned about the distant future or do not believe sea level will rise. This article demonstrates that it would be irrational to delay policy formulation until sea level rise projections are more precise. The cost will be small if we act now but great if we wait| and sea level is already rising along most coasts. The US government should develop a strategy in the next three years. 3589,1991,2,3,GREENHOUSE-EFFECT AND SEA-LEVEL RISE - THE COST OF HOLDING BACK THE SEA,Previous studies suggest that the expected global warming from the greenhouse effect could raise sea level 50 to 200 cm (2 to 7 ft) in the next century. This article presents the first nationwide assessment of the primary impacts of such a rise on the United States: (1) the cost of protecting ocean resort communities by pumping sand onto beaches and gradually raising barrier islands in place; (2) the cost of protecting developed areas along sheltered waters through the use of levees (dikes) and bulkheads; and (3) the loss of coastal wetlands and undeveloped lowlands. The total cost for a 1-m rise would be between $270 and $475 billion| ignoring future development. We estimate that if no measures are taken to hold back the sea| a 1-m rise in sea level would inundate 30|000 sq km (14|000 sq mi)| with wet and dry land each accounting for about half the loss. The 1500 sq km (600-700 sq mi) of densely developed coastal lowlands could be protected for approximately $1000 to $2000 per year for a typical coastal lot. Given high coastal property values| holding back the sea would probably be cost-effective. The environmental consequences of doing so| however| may not be acceptable. Although the most common engineering solution for protecting the ocean coast| pumping sand| would allow us to keep our beaches| levees and bulkheads along sheltered waters would gradually eliminate most of the nation's wetland shorelines. To ensure the long-term survival of coastal wetlands| federal and state environmental agencies should begin to lay the groundwork for a gradual abandonment of coastal lowlands as sea level rises. 3585,1991,4,3,HALOCARBONS IN THE ATMOSPHERE - TRENDS AND VERTICAL PROFILES,Very stable halocarbons such as chlorofluorocarbons (CFCs) and carbon tetrachloride are responsible for both the stratospheric ozone depletion and the global warming as they accumulate in the atmosphere. Background atmospheric concentrations of CFCs and other halocarbons have been determined accurately and precisely at surface level both in the northern hemisphere (Hokkaido) and in the southern hemisphere (Antarctica). The atmospheric concentrations of CFC-11 and CFC-12 have been increasing by 4% a year since 1979; the CFC-113 concentration tends to increase much faster (10-20% a year). Vertical profiles of major CFCs upto the stratosphere as determined in balloon experiments (grab-sampling and cryogenic sampling) over Japan reflect their behaviors in the stratospheric UV photolysis. 3588,1991,4,3,HISTORY AND PATTERN OF DISTURBANCE IN ALASKAN ARCTIC TERRESTRIAL ECOSYSTEMS - A HIERARCHICAL APPROACH TO ANALYZING LANDSCAPE CHANGE,(1) The history| types| and scales of disturbance in Arctic Alaska are reviewed and disturbances organized according to the spatial and temporal domains of Delcourt| Delcourt and Webb. This system is also used as a framework for a regional hierarchical geographic information system (GIS). (2) Natural disturbances vary from frequent small disturbances| such as needle-ice formation| to infrequent large disturbances| such as major glaciations. Most natural disturbances are either directly or indirectly climatically driven and are affected by climate changes| particularly changes to hydrologic regimes. The latter could be influenced by changes in either summer or winter precipitation patterns; increased temperature| which would melt ground ice; or changes in vegetation| which would affect evapotranspiration and run-off. (3) Most anthropogenic disturbances are microscale (10(-1) to 10(6) m2) phenomena| but cumulative impacts associated with large developments| such as the Prudhoe Bay Oil Field| have affected mesoscale regions (10(6)-10(10) m2)| and global warming could affect the tundra ecosystem at the macroscale level (10(10)-10(12) m2). (4) In the Arctic| recovery of the vegetation following disturbance is particularly closely linked to recovery of the physical system because of the presence of ice-rich permafrost. Maps of terrain sensitivity to disturbance must consider the influence of ground ice and heat flux to the system following disturbance. (5) A three-tiered GIS hierarchy with five sublevels is presented| with examples of typical scientific questions being addressed at each level| scales and types of databases| and linking elements between levels. (6) At the regional (macroscale and mesoscale) levels| the primary data sources are statellite-derived digital data. At the site level| integrated geobotanical databases derived from field surveys and photointerpretation are used in combination with digital terrain models. At the most detailed (plot or microsite) level| point sampling is used to portray vegetation structure and species composition in 1-m2 plots. (7) Linking or 'scaling-up' elements that affect landscape patterns at all scales are hydrology| geochemistry| and primary production. 2134,1991,2,3,HUMAN HEALTH-EFFECTS AND GLOBAL CLIMATE CHANGE,The implications for human health from global climate change are presented. Major human health hazards that may occur include the following: an increase in air pollution related disease| especially lung disease in children| elderly| and people with pre-existing chronic lung disease; an increase in bioavailability and mobility of toxic metals as related to acid rain; possible increases in vector-borne disease into new geographic locations; an increase in the frequency and severity of skin cancers and eye diseases from stratospheric ozone depletion and increased UV; changes in biodiversity that impact medical research and treatment development; and the appearance of human health hazards from attempts to mitigate global climate change| for example| CFC replacement chemicals| alternative fuels| solar energy components| and increased use of nuclear energy.
3620,1991,2,4,ICE ON LAKE-ONTARIO AT KINGSTON,Observations are reported of freezeup| growth| decay| and breakup of ice during a 10-year period on Lake Ontario at Kingston. The date of freezeup is related to the date on which the running mean air temperature during n days fell to 0-degrees-C where 55 less-than-or-equal-to n less-than-or-equal-to 100 for early and late freezeup respectively. The mean duration of ice cover was 71.7 days (range 18-96 days). Average mean ice thickness was 32 cm and maximum ice thickness in a given year is related to the intensity of cooling measured in degree days of freezing. Breakup normally occurs more rapidly than in smaller| completely ice-covered lakes as a result of the mechanical action of waves and currents. It is estimated that the climatic warming predicted by Global Climate Models will result in little or no ice formation on this part of Lake Ontario. The close response of ice to climatic control while filtering minor fluctuations from the record offers a tool to assess the early stages of climatic warming. 3574,1991,2,3,IMPLICATIONS OF CO2 GLOBAL WARMING ON GREAT-LAKES ICE COVER,Statistical ice cover models were used to project daily mean basin ice cover and annual ice cover duration for Lakes Superior and Erie. Models were applied to a 1951-80 base period and to three 30-year steady double carbon dioxide (2 x CO2) scenarios produced by the Geophysical Fluid Dynamics Laboratory (GFDL)| the Goddard Institute of Space Studies (GISS)| and the Oregon State University (OSU) general circulation models. Ice cover estimates were made for the West| Central| and East Basins of Lake Erie and for the West| East| and Whitefish Bay Basins of Lake Superior. Average ice cover duration for the 1951-80 base period ranged from 13 to 16 weeks for individual lake basins. Reductions in average ice cover duration under the three 2 x CO2 scenarios for individual lake basins ranged from 5 to 12 weeks for the OSU scenario| 8 to 13 weeks for the GISS scenario| and 11 to 13 weeks for GFDL scenario. Winters without ice formation become common for Lake Superior under the GFDL scenario and under all three 2 x CO2 scenarios for the Central and East Basins of Lake Erie. During an average 2 x CO2 winter| ice cover would be limited to the shallow areas of Lakes Erie and Superior. Because of uncertainties in the ice cover models| the results given here represent only a first approximation and are likely to represent an upper limit of the extent and duration of ice cover under the climiate change projected by the three 2 x CO2 scenarios. Notwithstanding these limitations| ice cover projected by the 2 x CO2 scenarios provides a preliminary assessment of the potential sensitivity of the Great Lakes ice cover to global warming. Potential environmental and socioeconomic impacts of a 2 x CO2 warming include year-round navigation| change in abundance of some fish species in the Great Lakes| discontinuation or reduction of winter recreational activities| and an increase in winter lake evaporation. 2139,1991,4,4,IMPLICATIONS OF GLOBAL CLIMATE CHANGE FOR BIOGEOGRAPHIC PATTERNS IN THE GREATER YELLOWSTONE ECOSYSTEM,Projected changes in global climate have substantial ramifications for biological diversity and the management of natural areas. We explored the potential implications of global climate change for biogeographic patterns in the Greater Yellowstone Ecosystem by using a conceptual model to compare three likely climate scenarios: (1) warmer and drier than the present; (2) warmer and drier| but with a compensating increase in plant water use efficiency; and (3) warmer and wetter than the present. The logical consequences of each scenario are projected for several species and community types chosen to represent a range of local climate conditions and biotic responses in the Greater Yellowstone Ecosystem. The upper and lower timberline appear to be particularly sensitive to climate change. The upper timberline is likely to migrate upward in elevation in response to temperature changes| whereas the lower treeline may retreat under drier conditions or move down slope under wetter conditions. In all scenarios| the extent of alpine vegetation in the ecosystem decreased. Climate-induced changes in the fire regime in the Greater Yellowstone Ecosystem would probably have substantial consequences for the extent and age-class distribution of forest communities. Alterations in the distribution and extent of grassland communities would affect the populations of large ungulates. Our analyses suggest directions for establishing long-term measurements for the early detection of responses to climate change.
3553,1991,4,3,INTERPRETATION OF SNOW-CLIMATE FEEDBACK AS PRODUCED BY 17 GENERAL-CIRCULATION MODELS,Snow feedback is expected to amplify global warming caused by increasing concentrations of atmospheric greenhouse gases. The conventional explanation is that a warmer Earth will have less snow cover| resulting in a darker planet that absorbs more solar radiation. An intercomparison of 17 general circulation models| for which perturbations of sea surface temperature were used as a surrogate climate change| suggests that this explanation is overly simplistic. The results instead indicate that additional amplification or moderation may be caused both by cloud interactions and longwave radiation. One measure of this net effect of snow feedback was found to differ markedly among the 17 climate models| ranging from weak negative feedback in some models to strong positive feedback in others. 3600,1991,5,3,IS THE EXTENT OF GLACIATION LIMITED BY MARINE GAS-HYDRATES,Methane may have been released to the atmosphere during the Quaternary from Arctic shelf gas-hydrates as a result of thermal decomposition caused by climatic warming and rising sea-level; this release of methane (a greenhouse gas) may represent a positive feedback on global warming [Revelle| 1983; Kvenvolden| 1988a; Nisbet| 1990]. We consider the response to sea-level changes by the immense amount of gas-hydrate that exists in continental rise sediments| and suggest that the reverse situation may apply -- that release of methane trapped in the deep-sea sediments as gas-hydrates may provide a negative feedback to advancing glaciation. Methane is likely to be released from deep-sea gas-hydrates as sea-level falls because methane gas-hydrates decompose with pressure decrease. Methane would be released to sediment pore space at shallow sub-bottom depths (100's of meters beneath the seafloor| commonly at water depths of 500 to 4|000 m) producing zones of markedly decreased sediment strength| leading to slumping [Carpenter| 1981; Kayen| 1988] and abrupt release of the gas. Methane is likely to be released to the atmosphere in spikes that become larger and more frequent as glaciation progresses. Because addition of methane to the atmosphere warms the planet| this process provides a negative feedback to glaciation| and could trigger deglaciation. 3590,1991,2,4,LAND-USE IMPLICATIONS OF SEA-LEVEL RISE - A CASE-STUDY AT MYRTLE-BEACH| SOUTH-CAROLINA,The prospect of global warming and consequent sea level rise will have important implications for coastal communities. This article examines the land use implications of alternate sea level rise scenarios on the city of Myrtle Beach| South Carolina. Current trends as well as high and low sea level rise scenarios are superimposed on the city's beach profile and near shore contours to estimate the type and value of land development likely to be impacted. It is found that losses associated with accelerated sea level rise would be particularly high in the city's hotel district and that overall property loss could range from 21 to 60% of the city's total property value. To lessen these potential losses| coastal communities such as Myrtle Beach must choose among one of three policy options including: (1) barricade the beach| (2) raise the land| and (3) implement a strategic retreat. Specific alternatives within each of these options are explored in turn. The article concludes that successful development plans will incorporate ground rules sensitive to and consistent with dynamic coastal processes. 3618,1991,3,3,LEAST-COST GREENHOUSE PLANNING - SUPPLY CURVES FOR GLOBAL WARMING ABATEMENT,This paper presents a methodology for comparing the cost-effectiveness of different technical options for the abatement of greenhouse gas emissions. The methodology also allows a determination of the extent to which each technology can contribute to abatement by a specified date. The primary focus of the paper concerns carbon dioxide (CO2) emissions. The analysis concludes that of seventeen different abatement options examined| the nuclear option is the most expensive| except for the marginal CO2 savings achieved from advanced coal technology. A combination of energy efficiency measures and high efficiency gas-fired generation can achieve CO2 savings approaching 285 million tonnes per year by year 2005. This represents a saving of 46.5% over existing emissions from the stationary sector (ie excluding transport). If the analysis is extended to include the effect of methane emissions from fossil fuel cycles| the advantages of energy efficiency and the renewable generating sources is improved. 3573,1991,2,4,LIKELY CLIMATIC CHANGES AND THEIR IMPACT ON THE NORTHERN PASTORAL INDUSTRY,Global warming is predicted to have less impact on northern than southern Australia due to temperature increase being least at the equator and increasing polewards. Estimates for northern Australia suggest an increase in temperature of 1 or 2-degrees-C in northern coastal areas and 2 to 4-degrees-C inland by the year 2030. Summer rainfall could increase by +10 to +20%. Warming in inland regions could result in a southwards shift of the northern limits of the sheep industry| the frost zone and the winter growing species. The shift could be of the order of 1.5 degrees of latitude for 1-degrees-C increase in temperature. The seasonality and monsoonal nature of rainfall in northern Australia will increase the importance of soil characteristics| especially for the Vertisols. Within regions| day length and solar radiation will not change but rainfall and temperature will change| creating new climates to which indigenous and introduced species may not be adapted. Increased water use efficiency due to higher CO2 levels and stomatal closure during the day could offset the predicted negative effect of higher temperature on plant growth. Pasture legumes| being C3 plants| could benefit from increased atmospheric carbon dioxide levels. Research is needed to develop more comprehensive pasture-plant models and to provide better predictions using regional climate model output. 3530,1991,3,3,LIMITING EMISSIONS OF THE GREENHOUSE GAS| CO2,While considerable global warming uncertainties remain| limiting the emission of the greenhouse gas| CO2| at minimum cost is a growing social concern. An approach suggested is to generate electricity by processes that facilitate capture of the CO2| and then to compress and inject it into suitable underground formations. By using formations containing uneconomical deposits of energy sources such as oil| gas| Fe++| coal| etc.| underground bioconversion of the CO2 to recoverable fuel forms may prove possible. 3519,1991,2,4,LOCAL-GOVERNMENT AND PUBLIC ADAPTATION TO SEA-LEVEL RISE,Global warming could result in a rise in global mean sea level of 9-29 cm between 1990 and 2030. By the end of the 21st century| global mean sea level could stand 30-110 cm higher than in 1990. Those projections suggest that sea level could rise between 3 and 10 cm per decade during the next century. This is a marked acceleration over the increase of 1-2 cm per decade observed during the past century. How will local governments and citizens respond? What are the obstacles to local government and public cognition of| and response to| sea-level rise? This paper reviews some of the basic issues involved in responding to accelerated sea-level rise; the range of possible policy responses; the extent to which local governments and the public perceive and respond to threats of sea-level rise; and the need for research into the determinants of cognition and response. 3521,1991,2,4,MANAGING THE INDUS RIVER BASIN IN LIGHT OF CLIMATE CHANGE - 4 CONCEPTUAL APPROACHES,Global warming raises troubling questions about the ecological and economic future of large irrigated river basins such as the Indus River in Pakistan. But it is not clear how potential impacts might best be identified or addressed. This article reports on a multidisciplinary study of four distinct conceptual approaches to climate change: climate scenarios assessment; critical water management problems; historic antecedents and analogies; and Muslim political reconstruction. Current scientific research emphasizes the first approach| but the other three may be more important for water managers in the basin. The article reviews previous research on water resources effects of climate change; introduces the Indus basin; discusses the four conceptual approaches; and finally discusses prospects for coordinating them. 3513,1991,2,4,MERCURY AND MONOMETHYLMERCURY - PRESENT AND FUTURE CONCERNS,Global atmospheric changes carry the potential to disrupt the normal cycling of mercury and its compounds. Acid rain may increase methylmercury levels in freshwater fish. Global warming and increased ultraviolet radiation may affect the global budget of methylmercury| including its formation and degradation in both biotic and abiotic environments. In this article we review current knowledge on mercury and monomethylmercury with regard to their environmental fate and the potential for human health effects. Recent findings indicate that atmospheric Hg deposition readily accounts for the total mass of Hg in fish| water| and sediment of Little Rock Lake| a representative temperate seepage lake in north-central Wisconsin. It is strikingly evident that modest increases in atmospheric Hg loading could lead directly to elevated levels in the fish stock. It is doubtful| given the experimental limitations in many recent studies| that the temporal pattern for Hg emissions| for background atmospheric Hg concentrations| and for changes in Hg depositional fluxes has been identified. Thus| the present and future questions of whether the environmental impact is of local| regional| or hemispheric significance remain. Contemporary investigations must address these important questions. Human exposure to methylmercury in the United States is probably increasing due to increased consumption of fish and fish products. A recent epidemiological investigation indicates high susceptibility to brain damage during prenatal exposures to Hg. An important objective for future investigation is to establish the lowest effect level for human exposure to methylmercury. 3609,1991,4,4,MICROWAVE SOUNDING UNITS AND GLOBAL WARMING - RESPONSE,In their research article "Precise monitoring of global temperature trends from satellites|" R. W. Spencer and J. R. Christy assert(1) that satellite microwave sounding units(MSUs) exhibit superb stability and may be used to monitor global warming in a way that is not possible by other means.
2142,1991,3,3,MITIGATION OPTIONS AND ECONOMIC CONSEQUENCES,This paper discusses the limitations of applying the traditional economic tool of cost-benefit analysis to considering strategies that would mitigate the effects of global climate change. These studies are the basis for many policies that claim that addressing the risks of global climate change is prohibitively expensive. This paper presents another type of analytical framework-the end-use study. Used extensively by engineers and scientists| end-use studies attempt to project future energy needs and then consider how to best meet the expected need| which contrasts with traditional econometric methods that focus almost exclusively on energy pricing.
3577,1991,2,2,MODEL ESTIMATES OF CO2 EMISSIONS FROM SOIL IN RESPONSE TO GLOBAL WARMING,ONE effect of global warming will be to accelerate the decomposition of soil organic matter| thereby releasing CO2 to the atmosphere| which will further enhance the warming trend 1-7. Such a feedback mechanism could be quantitatively important| because CO2 is thought to be responsible for approximately 55% of the increase in radiative forcing arising from anthropogenic emissions of gases to the atmosphere 8| and there is about twice as much carbon in the top metre of soil as in the atmosphere 9. Here we use the Rothamsted model for the turnover of organic matter in soil 3 to calculate the amount of CO2 that would be released from the world stock of soil organic matter if temperatures increase as predicted| the annual return of plant debris to the soil being held constant. If world temperatures rise by 0.03-degrees-C yr-1 (the increase considered as most likely by the Intergovernmental Panel on Climate Change 8)| we estimate that the additional release of CO2 from soil organic matter over the next 60 years will be 61 x 10(15) gC. This is approximately 19% of the CO2 that will be released by combustion of fossil fuel during the next 60 years if present use of fuel continues unabated. 3599,1991,3,4,MODELING OF THE CHEMISTRY OF WET LIMESTONE FLUE-GAS DESULFURIZATION SYSTEMS,The chemistry of wet limestone flue gas desulfurization (FGD) systems is complicated by the interaction of dissolved SO2 and dissolved nitrogen oxides. A substantial number of nitrogen-sulfur compounds can be formed from the reactions of sulfite and bisulfite ions with nitrogen oxyanions. A computer model is used to simulate the kinetics and to determine the effect of scrubber operating conditions on the production of nitrogen-sulfur compounds. With increasingly stringent regulations covering solid and liquid waste disposal| it is important to minimize undesirable byproducts in FGD systems. The modeling is also used to study the effect of scrubber conditions on the production of N2O (nitrous oxide). Emission of N2O into the atmosphere is undesirable because it has both significant ozone depletion potential and global warming potential. 3536,1991,2,4,MODIFICATION OF THE RESPONSE OF PHOTOSYNTHETIC PRODUCTIVITY TO RISING TEMPERATURE BY ATMOSPHERIC CO2 CONCENTRATIONS - HAS ITS IMPORTANCE BEEN UNDERESTIMATED,Climate change will include correlated increases in temperature and atmospheric CO2 concentration (C(a)). Rising temperatures will increase the ratio of photorespiratory loss of carbon to photosynthetic gain| whilst rising C(a) will have an opposing effect. The mechanism of these effects at the level of carboxylation in C3 photosynthesis are quantitatively well understood and provide a basis for models of the response of leaf and canopy carbon exchange to climate change. The principles of such a model are referred to here and used to quantitatively examine the implications of concurrent increase in temperature and C(a). Simulations of leaf photosynthesis show the increase| with elevation of C(a) from 350 to 650-mu-mol mol-1| in light saturated rates of CO2 uptake (A(sat)) and maximum quantum yields (phi) to rise with temperature. An increase in C(a) from 350 to 650-mu-mol mol-1 can increase A(sat) by 20% at 10-degrees-C and by 105% at 35-degrees-C| and can raise the temperature optimum of A(sat) by 5-degrees-C. This pattern of change agrees closely with experimental data. At the canopy level| simulations also suggest a strong interaction of increased temperature and CO2 concentration. Predictions are compared with the findings of long-term field studies. The principles used here suggest that elevated C(a) will alter both the magnitude of the response of leaf and canopy carbon gain to rising temperature| and sometimes| the direction of response. Findings question the value of models for predicting plant production in response to climate change which ignore the direct effects of rising C(a) and the modifications that rising C(a) imposes on the temperature response of net CO2 exchange. 2161,1991,2,3,MYCORRHIZAL MEDIATION OF PLANT-RESPONSE TO ATMOSPHERIC CHANGE - AIR-QUALITY CONCEPTS AND RESEARCH CONSIDERATIONS,The term 'global climate change' encompasses many physical and chemical changes in the atmosphere that have been induced by anthropogenic pollutants. Increases in concentrations of CO2 and CH4 enhance the 'greenhouse effect' of the atmosphere and may contribute to changes in temperature and precipitation patterns at the earth's surface. Nitrogen oxides and SO2 are phytotoxic and also react with other pollutants to produce other phytotoxins in the troposphere such as O3 and acidic substances. However| release of chlorofluorocarbons into the atmosphere may cause depletion of stratospheric O3| increasing the transmittance of ultraviolet-B (UV-B) radiation to the earth's surface. Increased intensities of UV-B could affect plants and enhance photochemical reactions that generate some phytotoxic pollutants. The role of mycorrhizae in plant responses to such stresses has received little attention. Although plans for several research programs have acknowledged the importance of drought tolerance and soil fertility in plant responses to atmospheric stresses| mycorrhizae are rarely targeted to receive specific investigation. Most vascular land plants form mycorrhizae| so the role of mycorrhizae in mediating plant responses to atmospheric change may be an important consideration in predicting effects of atmospheric changes on plants in managed and natural ecosystems.
3551,1991,3,3,NATIONAL LEGISLATION AND OTHER OPTIONS FOR ADDRESSING POTENTIAL GLOBAL WARMING,Americans| as citizens of a powerful| industrialized country| must recognize that we are putting pollutants into our atmosphere. We must also acknowledge the fact that we have a significant role to play in being part of the solution. When planning to develop legislation to deal with any issue| the legislator must be aware of certain problems. First| there must be an identified problem. Then he or she must recognize that the development of legislation is tedious and precise. The bill that is written must be substantive| have clear goals| and be very focused. One should also keep in mind that there must be a consensus to pass the bill.
3533,1991,2,4,NEAR-FUTURE SEA-LEVEL IMPACTS ON COASTAL DUNE LANDSCAPES,Very little attention has been paid to the impact of global warming| especially sea level rise| on coastal dune-scapes| despite the fact that these provide natural protection along many of the world's shorelines. This paper reviews likely responses given the IPCC climate change predictions to 2030AD| which include sea level rise in the order of 0.09 to 0.29m. It is envisaged that coastal dunes will react in a variety of ways dependent both on regional and local factors. Rising water levels will increase susceptibility to erosion| but the fate of released sediment| particularly the onshore/offshore partitioning| must depend on morphodynamic antecedence| and the propensity for periodic domain shifts. The release of material at the shoreline may allow construction of coastal dunes| to the point of progradation in some zones. The response of dune vegetation to a warmer| wetter climate is uncertain. Most of the main temperate dune species are C3 plants which given favourable conditions would respond positively to CO2 enhancement. However local factors may offset such potential gains. 2149,1991,4,4,NEW ASSESSMENTS OF GLOBAL CLIMATE CHANGE,Based on discussions at a Session of the Intergovernmental Committee on Climate Change Working Group 1 held during the period February 26 - March 2| 1990 in Great Britain| and in the context of the WG-1 Report| a review has been made of the state-of-the-art of studies on global climate change. A consensus has been reached on one of the most important conclusions that the causes of the climate warming observed during the last century remain still unclear. This determines the top urgency of studies and quantitative assessments of the internally forced variability of the climate system| without which the "filtering-out" of anthropogenic impacts on climate cannot be reliable. Such insufficiently studied factors of climate formation as ocean-atmosphere and cloud-radiation interactions are the most substantial aspects of the internal variability. The related unsolved problems have been discussed.
3592,1991,4,4,OCEAN CIRCULATION AND OCEAN-ATMOSPHERE EXCHANGES,The oceans have a major influence on climate through the ocean-atmosphere exchange processes. However| limits to our present understanding of some of these processes is an important factor in our inability to model climate change precisely. Present knowledge of ocean structure and circulation is reviewed| with a particular emphasis on the Southern Hemisphere oceans| and the major ocean-atmosphere exchanges are examined. The influence of interhemispheric asymmetries in global warming scenarios is discussed. An improved understanding of the oceans and therefore better climate models will result from planned international ocean research experiments in the 1990s. 2132,1991,4,4,ON DETERMINING THE STATISTICAL SIGNIFICANCE OF DISCONTINUITIES WITHIN ORDERED ECOLOGICAL DATA,Current ecological theory hypothesizes that boundaries between adjacent ecosystem units are important in determining ecosystem structure and function across heterogeneous landscapes| and that such boundaries are potentially important sites for early detection of global climate change effects. Hence| there is an increasing research effort to elucidate the structure and function of ecological boundaries. Yet traditional data analysis methods focus primarily on homogeneous units rather than on the boundaries between them; thus| new methods are being developed for detecting| characterizing and classifying boundaries| e.g.| split moving-window boundary analysis (SMW). SMW is a simple yet sensitive method for locating discontinuities that may exist within multivariate| serial data (ordered in one dimension) at various scales relative to the length of the data series. However| SMW is subjective and relative| and therefore locates apparent discontinuities even within random| serial data. In this paper we present two nonparametric methods for determining the statistical significance of discontinuities detected by SMW. First| we describe a Monte Carlo method for determining the statistical significance of scale-dependent discontinuities (i.e.| discontinuities that are significant relative to only one scale). Second| we propose a nonparametric| scale-independent method (it also is dependent upon scale size| but to a much lesser degree than the Monte Carlo method) that is more appropriate for locating statistically significant discontinuities that separate different| relatively homogeneous groups of varying size along a series. We examine the robustness of these two methods using computer-generated data having varying intensities of imposed discontinuities| and illustrate their application to locating boundaries between vegetation samples collected at systematic intervals across a desert landscape in southern New Mexico| USA.
2136,1991,3,3,OPPORTUNITIES FOR CARBON EMISSIONS CONTROL IN POLAND,Poland is an important case study in understanding the role of international cooperation in reducing the risk of global climate change. Currently Poland is experiencing vast changes in its economic structure and energy and environmental policies. This transition has the potential to translate into substantial energy savings and CO2 emissions reductions. The impact of Poland's current efforts will depend largely on the successful implementation of a wide range of already enacted energy laws and regulations| the effective use of incentives and disincentives to decrease energy consumption and the extent to which the international community aids Poland in its quest for improved energy efficiency and environmental protection.
3613,1991,3,2,PASSIVE-SOLAR SCHOOLS IN THE UK,There are currently approximately 23 000 primary and 5000 secondary schools in the UK. (Survey of School Buildings| UK Department of Education and Science| HMSO| London| 1987).1 The total rate of expenditure on fuel for heating and lighting these buildings is about 75 pound sterling million per annum. The dissipation of energy| derived from fossil fuels| in buildings accounts for approximately 24% of the CO2 emissions| and so is a considerable contributor to the excess greenhouse effect and hence global warming. Practising energy thrift in schools therefore represents a considerable opportunity for achieving significant savings with respect to running costs and achieving a more sustainable society. Thus it is not surprising that the number of school buildings incorporating one set of measures| the so-called 'passive-solar' features| is increasing. Such buildings possess the ability to be thermally comfortable while providing mentally-stimulating environments| yet require significantly reduced rates of fossil-fuel consumption compared with those for 'conventional' buildings of similar sizes. The behaviours of six such passive-solar schools have been studied and the effectiveness of each of them has been assessed. Recommendations concerning the inclusion of passive-solar features in educational buildings are made. 3615,1991,2,4,PERTURBATIONS TO TROPOSPHERIC OXIDANTS| 1985-2035 .2. CALCULATIONS OF HYDROGEN-PEROXIDE IN CHEMICALLY COHERENT REGIONS,Increasing global emissions of trace gases NO| CH4| and CO| along with perturbations initiated by changes in stratospheric O3 and H2O| may cause tropospheric hydrogen peroxide (H2O2) levels to change. Specific scenarios of CH4-CO-NO emissions and global climate changes are used to predict HO2 and H2O2 changes from 1985 to 2035 in a one-dimensional model that simulates different chemically coherent regions (e.g. urban| non-urban continental and marine mid-lattitudes; marine and continental low latitudes). If CH4 and CO emissions continue to increase throughout the troposphere at current rates (1% yr-1)| there will be large increases in H2O2| for example| more than 100% in the urban boundary layer from 1985 to 2035. Globally| H2O2 will increase 22% with HO2 increasing 8% and O3 increasing 13%. When CH4| CO and NO emissions are specified on a regionally varying basis and are parameterized for high and low potential growth rates| globally averaged increases in surface concentrations are 12% for H2O2 and 18% for O3. A global warming (with increased H2O vapor) or stratospheric O3 depletion superimposed on CH4| CO and NO emissions changes will cut O3 increases but add to peroxide| increasing levels as much as 150% above present day in some regions. Both globally uniform and region-specific scenarios predict a 10-15% loss in global OH from 1985 to 2035. Thus| conversion of OH to HO2 and H2O2 in the atmosphere may signify a loss of gaseous oxidizing capacity in the atmosphere and an increase in aqueous-phase oxidizing capacity. 3606,1991,3,2,PHOTOVOLTAICS AND MATERIALS SCIENCE - HELPING TO MEET THE ENVIRONMENTAL IMPERATIVES OF CLEAN-AIR AND CLIMATE CHANGE,Human activity is altering the composition of the atmosphere in unprecedented ways. Fossil fuel combustion| which currently releases 5.6 billion metric tons of carbon annually| in combination with deforestation| has increased atmospheric concentrations of carbon dioxide 25% above pre-industrial levels. Carbon dioxide and other greenhouse gases trap infrared radiation from the earth altering its thermal balance. While carbon dioxide is anticipated to contribute about one-half of human induced global warming| the world energy sector is responsible for an estimated 57% of future global warming when contributions from additional combustion related pollutants are included. In order to stabilize atmospheric concentrations of carbon dioxide even at current elevated levels| computer models suggest the need to reduce emission rates by approximately 75%. Present patterns of energy use are also contributing to major air pollution problems. An analysis of policy options shows that a combination of vastly improved energy efficiency strategies and carbon free energy production technologies are essential to simultaneously slow the rate of global warming and improve air quality. This paper summarizes current knowledge of the greenhouse effect and its consequences| and examines how photovoltaic electricity can contribute to atmospheric stabilization goals. Some specific examples and strategies will be given that may accelerate the rate at which photovoltaic technologies can penetrate the market. Should these strategies succeed| it will have major implications for materials science including increased attention to pollution problems associated with the manufacture of many promising photovoltaic technologies. 3524,1991,3,3,PLANNING FOR FUTURE UNCERTAINTIES IN ELECTRIC-POWER GENERATION - AN ANALYSIS OF TRANSITIONAL STRATEGIES FOR REDUCTION OF CARBON AND SULFUR EMISSIONS,The objective of this paper is to identify strategies for the U.S. electric utility industry for reduction of both acid rain producing and global warming gasses. The research used the EPRI Electric Generation Expansion Analysis System (EGEAS) utility optimization / simulation modeling structure and the EPRI developed regional utilities. It focuses on the North East and East Central region of the U.S. Strategies identified were fuel switching -- predominantly between coal and natural gas| mandated emission limits| and a carbon tax. The overall conclusions of the study are that using less (conservation) will always benefit Carbon Emissions but may or may not benefit Acid Rain emissions by the off setting forces of improved performance of new plant as opposed to reduced overall consumption of final product. Results of the study are highly utility and regional demand specific. The study showed| however| that significant reductions in both acid rain and global warming gas production could be achieved with relatively small increases in the overall cost of production of electricity and that the current dispatch logics available to the utility control rooms were adequate to reschedule dispatch to meet these objectives. 3541,1991,2,4,POLICY IMPLICATIONS OF GLOBAL WARMING FOR THE NORTHWEST,Regional climate changes are more uncertain than global changes. There are| however| possible regional consequences whose effects are important to recognize. Global warming is likely to raise sea level in some areas and may increase the incidence and severity of river flooding in the Pacific Northwest. Winter snowpack in the mountains may be significantly affected| with consequent effects on water resources available for power generation| irrigation| and fisheries and with effects on agriculture and forestry. Even though uncertainties are considerable| we should not wait to put in place policies and procedures that could provide for flexibility and the use of new understanding as it develops. Climate change should be expected and planned for by the public and by local| state| and federal agencies. 3515,1991,3,4,POSSIBLE BIOGEOCHEMICAL CONSEQUENCES OF OCEAN FERTILIZATION,We consider biogeochemical secondary effects that could arise from an increase in ocean productivity| such as may occur via fertilization with Fe. These processes and feedback loops are infrequently discussed in this context| yet are likely to be highly relevant to the understanding of global change in general. In particular| we suggest that increased productivity may increase the production and efflux of greenhouse gases| such as nitrous oxide (N2O) and methane (CH4) and that shifts in phytoplankton species and productivity may cause changes in another climate-related gas| dimethylsulfide (DMS). N2O is also implicated in the destruction of stratospheric ozone. Factors contributing to amplified release include both increased nutrient cycling in general and possible development of low oxygen conditions from fertilization. It is also remotely possible that reduced oxygen from an initial fertilization could mobilize existing Fe pools| inducing uncontrolled self-fertilization. Although lack of relevant physiological and ecological data makes it difficult to provide quantitative limits on the extent of the undesired effects| rough calculations suggest that the enhanced release of N2O alone could totally negate any potential benefit from fertilization and likely worsen global warming and ozone depletion. 3594,1991,2,4,POSSIBLE IMPACT OF GLOBAL WARMING ON CABBAGE ROOT FLY (DELIA-RADICUM) ACTIVITY IN THE UK,A program for simulating the patterns of egg-laying by populations of the cabbage root fly was used to model the effects of global warming on future cabbage root fly attacks. An increase of 3-degrees-C in mean daily temperature would cause the cabbage root fly to become active about a month earlier in the year than at present. Under such conditions| the emergence of flies from the overwintering population would be less synchronised| as the completion of diapause and post-diapause development would occur at the same time in different individuals within the population. However| there would continue to be only three generations of fly each year| even in the south of England. With temperature increases of 5-degrees-C or 10-degrees-C| the fly would complete four generations each year and aestivation would seriously disrupt egglaying. These rises in temperature would have a major impact on cabbage root fly activity and would require new strategties for controlling this pest. 3535,1991,2,3,POSSIBLE IMPACTS OF CLIMATIC WARMING SCENARIOS ON WATER-RESOURCES IN THE SASKATCHEWAN RIVER SUBBASIN| CANADA,Regional scale studies of the impacts of global warming scenarios provide a useful mechanism for identifying potential regional sensitivities| data gaps and research needs| and for raising awareness of the global warming issue at the regional level. Thus| a pilot study of water resources in the Saskatchewan River Sub-basin was undertaken in order to provide first-cut estimates of impacts in this region| and to identify future research needs. Thirty scenarios were constructed| using two hypothetical growth rates for irrigation| five scenarios based on outputs from General Circulation Models (GCMs)| and ten hypothetical warming scenarios. During the course of this study| a number of methodological questions were raised| including the representativeness of data points| interpolation of observed and scenario data| and the quantification of uncertainty. Results indicated decreases in summer soil moisture and increases in irrigation demand| but no consensus on changes in runoff or annual net basin supply| primarily due to differences in the GCM-based scenario output at the Rocky Mountains| the major source region for runoff. There were a number of recommendations for follow-up research and monitoring. 3544,1991,2,3,POTENTIAL EFFECTS OF GLOBAL WARMING ON WHITEFISH IN LAKE CONSTANCE| GERMANY,A doubling of the present global atmospheric CO2 concentration is expected to occur sometime during the middle of the 21 st century and climatologists have predicted that this will result in an increase in the global mean air temperature ranging from 1.5-degrees-4.5-degrees-C. Fisheries resources are highly responsive to water temperature varirations and will likely undergo marked change as well. We present several predictions for the whitefish (Coregonus lavaretus) population of prealpine Lake Constance and| for the early stages of each warming scenario| an increase in whitefish abundance is predicted. Negative effects limiting population growth will probably set in during the latter stages of the 3.0-degrees and 4.5-degrees-C CO2 doubling scenarios. Of chief importance to population restructuring is the timing of temperature increases during specific periods of the year and whether these temperature increases co-occur with fragile| temperature-sensitive early life stages. Our predictions are based on April and May lake-surface temperatures| since during these months whitefish larvae inhabit the lake's surface waters and exhibit substantially faster growth and higher survival when the surface is warm as opposed to cold. In the historical record there exists no evidence that temperature fluctuations during the other ten months of the year influence whitefish recruitment. In a warmer climate| however| mild winters may prevent oxygen enrichment of deep water causing high egg mortalities. Whitefish in shallow lakes (< 20 m deep) may not respond as favorably to global warming. 2157,1991,2,2,POTENTIAL IMPACTS OF GLOBAL CLIMATE CHANGE ON PACIFIC-NORTHWEST SPRING CHINOOK SALMON (ONCORHYNCHUS-TSHAWYTSCHA) - AN EXPLORATORY CASE-STUDY,Increases in atmospheric concentrations of greenhouse gases are predicted to raise global temperatures by up to 3-degrees-C over the next one-hundred years| which may have significant effects on natural resources. Even a smaller (2-degrees-C) temperature change may impact one prominent Pacific Northwest natural resource| the spring chinook salmon| Oncorhynchus tshawytscha. A computer model was developed by the Northwest Power Planning Council (NPPC) for use in developing the NPPC salmon enhancement plan for their Fish and Wildlife Program. Using this model| we investigate the impact of global warming on the production of spring chinook salmon in the Yakima subbasin of the Columbia River System. The model simulates current prevailing environmental conditions and the implementation of improvements in salmon habitat planned by the NPPC. The data are then changed to reflect conditions that we infer to have existed between 6|000 and 8|000 years ago| when temperatures were approximately 2-degrees-C warmer than today. When the NPPC computer model is run under these altered conditions| it shows that projected climate change might reduce by half the Yakima River spring chinook salmon production predicted under both current and NPPC-improved conditions. These results strongly support the need for planned improvements in the fishery| since a 50% decline in existing fish populations could decrease spring chinook salmon-and possibly other salmonid populations-beneath levels needed for the survival of the species. More broadly| the results suggest that if future global warming takes a form similar to that of 6|000 years ago| it could have major effects on the salmon population of the Pacific Northwest. Although some races of salmon might have their survival enhanced| others might be harmed. We recognize that all species and races would not be affected in the same way as Yakima River spring chinook| yet global warming is still a matter of concern because many of the Pacific Northwest salmon stocks are already under stress from other causes. A more comprehensive and thorough analysis is urgently needed.
3568,1991,4,4,PRECISION TROPOSPHERIC TEMPERATURE MONITORING 1979-1990,The TIROS-N microwave sounding units (MSU's) have demonstrated an ability to measure globally averaged tropospheric brightness temperature anomalies to a precision of 0.01-degrees-C per month. This has been revealed by five separate overlap periods of concurrently operating morning and afternoon satellites. For MSU channel 2| comparisons to ten years of radiosonde data show that these anomalies are closely related to anomalies in 850-300 mbar thickness| with gridpoint correlations to radiosondes usually ranging between 0.85 and 0.95. The comparisons also suggest that there is no drift or bias in the MSU's (or US-controlled radiosonde system) between 1979-1988 to about 0.01-degrees-C when results are averaged over the Pacific or Caribbean. The non-trivial amount of lower stratospheric influence on MSU channel 2| combined with evidence for cooling in that layer during 1979-1990| suggests the need for removal of this effect from the measurements before interpretation in terms of a "tropospheric" temperature. Because the NOAA-6 MSU channel 3 was not usable for precision climate monitoring due to a sizeable drift| we have performed a retrieval on MSU channel 2 at different view angles to achieve stratospheric cancellation. We present global brightness temperature anomalies of both raw channel 2 and the tropospheric retrieval for the period 1979-1990. It appears that the MSU's (and presumably the advanced microwave sounding units as well) will provide a valuable resource for not only monitoring intraseasonal to interannual climate change| but also for long-term monitoring of potential global warming. 3550,1991,4,3,PREDICTING CLIMATE CHANGE FOR THE PACIFIC-NORTHWEST,Determining the nature and extent of greenhouse warming is a difficult problem because the global climate system is complex and influenced by many factors. The authors show that climate warm- shinging is a certainty| but that much uncertainty surrounds predicting how much and when. They present the theoretical basis of the global warming issue| review the effectiveness of computer models in assessing climate change| and discuss the needs for improvements in those models. 3628,1991,3,4,PROJECT PHOENIX - CONFRONTING GLOBAL WARMING WITH SOLAR POWER,Project Phoenix is a design proposal for a combination of projects to combat global warming. In this paper| one of these is explained - a plan for solar power satellites to reduce dependence on fossil fuels. In the plan| the Moon is the prime source of functional and structural materials. Large| 10-gigawatt| double-cone satellites 9.25 kilometers in diameter are constructed in lunar orbit and towed to geosynchronous orbit. 3591,1991,3,3,PROMOTING ENERGY-CONSERVATION IN SMALL AND MEDIUM-SIZED COMPANIES,To avoid the risk of global warming energy conservation is becoming increasingly important. In small and medium-sized firms there are still many obstacles to using all profitable energy-saving investments and organizational measures. In a recent study detailed technical analyses in eitht industries| as well as in-depth interviews and a broad telephone survey with firms| were carried out. As a conclusion a bundle of activities is suggested to overcome the obstacles. Above all| these include the motivation of company managers| improved energy consultation| the use of the multiplicator function of the association and a stronger engagement of the state and the utilities. 3532,1991,5,3,QUATERNARY AND TERTIARY MICROFOSSILS FROM BENEATH ICE STREAM-B - EVIDENCE FOR A DYNAMIC WEST ANTARCTIC ICE-SHEET HISTORY,Some glaciologists have suggested that the West Antarctic Ice Sheet| which is grounded well below sea level| may be susceptible to rapid grounding-line retreat and disintegration. However| until now| geologic evidence of previous ice sheet "collapses" has been lacking. Sediments that have recently been collected from beneath the West Antarctic Ice Sheet at Ice Stream B contain direct evidence of icc-free conditions in the West Antarctic interior during certain Cenozoic intervals| both prior to and subsequent to the development of grounded ice sheets in West Antarctica. The sediments contain rare but diverse microfossils that represent a wide variety of biostratigraphic ages and depositional environments. Microfossils present include relatively common marine and non-marine diatoms and sponge spicules| plus rare foraminifera| nannofossils| radiolarians| silicoflagellates| chrysophyte cysts and palynomorphs. Clasts of Neogene freshwater diatomite demonstrate the former presence of large lake systems in West Antarctica| possibly as part the Cenozoic West Antarctic rift system. Age-diagnostic marine fossils in the sediment include Late Paleogene calcareous nannofossils and planktonic foraminifera| Miocene marine planktonic diatoms and| significantly| late Pleistocene marine diatoms. Relatively common late Miocene diatoms probably reflect marine deposition prior to initiation of a dominantly glacial phase in West Antarctica. It is likely that Pliocene and early Pleistocene diatoms were deposited in the West Antarctic interior during certain warm interglacials| but these have been eroded and transported toward the continental shelf edge during repeated ice sheet expansions. The late Pleistocene diatoms from Upstream B were deposited in the West Antarctic interior basins during a marine phase| subsequent to an ice sheet collapse| during at least one late Pleistocene interglacial. This discovery provides an indication of the complex history of the West Antarctic Ice Sheet| and calls into question some previous interpretations of ice sheet stability based on paleoceanographic proxy data. The results of this study may lend credence to the concern that global warming and rising sea levels in a "greenhouse" earth could lead to collapse of this marine ice sheet during the current interglacial period. 3554,1991,5,4,RECONSTRUCTION OF PAST CHANGES IN SALINITY AND CLIMATE USING A DIATOM-BASED TRANSFER-FUNCTION,THE prospect of global warming has focused attention on the role of palaeoecology in testing the accuracy and sensitivity of climate-model predictions| in identifying past analogues for future climate change| and in placing model-predicted climate responses in the context of natural climate variability 1|2. Proxy data for climate reconstruction can be derived from many sources| including the palaeolimnological record 3|4. In closed-basin lakes in arid and semi-arid regions| shifts in effective moisture lead to the concentration or dilution of dissolved salts| and these changes in salinity are clearly reflected in the composition of lacustrine diatom assemblages 5-8. Here we refine a previously published 9 diatom-based transfer function for the reconstruction of past changes in salinity of lakes in the northern Great Plains region of North America| and apply the refined transfer function to a late-glacial and Holocene sediment record from Devils Lake| North Dakota. Our results show that there were a number of alternations between fresh and saline conditions during the Holocene and hence demonstrate the utility of the technique in reconstructing past changes in regional climate. 3587,1991,2,4,REDUCED POSTFIRE TREE REGENERATION ALONG A BOREAL FOREST FOREST-TUNDRA TRANSECT IN NORTHERN QUEBEC,The large 1950s fires that burned > 5500 km2 of land across a south-to-north climatic gradient in northern Quebec provide an opportunity to evaluate the role of fire in forest-tundra development on a demographic basis. The tree population density before and almost-equal-to 30 yr after fire was estimated by censusing trees in plots of 400 m2 located in upland and lowland within four representative ecoregions of northern Quebec. The analysis of tree recruitment before and after fire| in 410 randomly selected sites along a transect crossing the upper boreal forest and forest-tundra zones| indicated that wildfires induced substantial depletion of tree populations. Taken as a whole| fires have significantly reduced the density of black spruce populations in forest-tundra uplands| but not in the lowlands. A reduction in tree population density of greater-than-or-equal-to 75% was observed in 22% of upper boreal forest sites| and 45% and 93% of sites located in the forest and shrub subzones| respectively| of the forest-tundra zone. Complete exclusion of tree populations by fire was observed in 43% of upland sites in the northern part of the transect| while complete removal was a rare event in the southern part. Sustained reduction of tree population density after several destructive fires appears as one of the main deforestation processes in the subarctic zone. This leads to the patchy distribution of forest stands and scattered tree populations typical of the forest-tundra biome. Comparisons with paleoecological data suggest that the impact of the 1950s fires contributed to the expansion of the forest tundra into the upper boreal forest. The ecological impact of these fires was probably similar to those fires responsible for development of the forest tundra during the Holocene. It is suggested that the fire-climate interaction should be considered in order to predict the ecological impact of warming climate on high-latitude forest ecosystems. 3537,1991,3,3,REDUCING CARBON-DIOXIDE EMISSIONS FROM AUSTRALIAN ENERGY USE,Debate about the increasing concentration of carbon dioxide (CO2) in the atmosphere| and fears that it will result in an intensification of the greenhouse effect and global warming| have spurred consideration of sustainable development. It has been claimed that technology to improve energy efficiency already exists that is cost-effective without consideration of the gains from abatement of carbon dioxide emissions. Likewise| changes in the behaviour of households or firms that would result in lower energy use per capita have been predicted as answers to the problem. But the question of implementation is often ignored or assumed away| while it should correctly be costed into the technology or the behavioral changes. This paper attempts to redress this lacuna in the debate| by analysing policy options within a framework of exchange| authority| or persuasion. Carbon taxes and lower interest rates are the recommendation. 3611,1991,2,4,REMOTE-SENSING OF PERMAFROST BY GROUND-PENETRATING RADAR AT 2 AIRPORTS IN ARCTIC CANADA,Over a cycle of seasons| ground-penetrating radar studies were carried out at Inuvik and Rankin Inlet| Northwest Territories. The two airports are part of the Forward Operating Location (FOL) program of the Department of National Defence and have been slated for significant upgrading of runways| taxiways and parking aprons. This provided a good opportunity to investigate the extent of permafrost and its seasonal variation at two locations distributed over a wide geographic area. The study method involved specific and repeated traverses with a Pulse EKKO III ground-penetrating radar unit. The survey was successful in locating massive ice bodies| imaging several existing problem areas beneath runways and mapping the seasonal depth of thaw in permafrost. The study results imply that future monitoring at FOL sites should be continued in light of suggested ground stability problems due to global warming. 3560,1991,2,4,RESEARCH IN THE MOUNTAINS OF THE ISLAND OF NEW-GUINEA,This paper summarizes the studies| both multidisciplinary and interdisciplinary| that have been carried out in the central cordillera of the island of New Guinea| both in the western sector| Irian Jaya which is part of Indonesia| and in the eastern sector which is the nation of Papua New Guinea. The highland valleys between 1|200 and 2|850 m have been inhabited by relatively large populations since prehistoric times. Early studies| beginning in the 1950s| were mainly ecological and related the people to their environment but more recent work has emphasized change and continuity through time| reconstructing landscapes and climates from prehistoric times| through a brief period of colonialization| to present independence. The landscape| with cultivation dependent on the sweet potato and pig breeding| is a result of environmental| economic| and social factors. Of concern for human occupation of the highlands are severe droughts| killing frosts| and heavy rains| and the possible consequences of global warming. The implications of research in terms of practical management relate to the effectiveness of indigenous land-use systems and their sensitivity to climatic and other variables. 3586,1991,3,2,RESPONSE TO SKEPTICS OF GLOBAL WARMING,The majority of the scientific community involved in climate research is convinced of the reality of a current and future global warming due to the greenhouse effect| a change that must be largely caused by human activities. However| a minority of scientists is still skeptical of the notion that mankind is significantly influencing the climate of the earth| and it therefore argues against taking certain measures to avert this alleged global warming. In recent years the media have given considerable coverage to the statements of these skeptics. Reasons for their statements range from a simple argument that we do not understand the earth's climate system well enough to predict the future| to more complex arguments involving negative feedbacks and changes of solar activity. They question whether the global temperature increase in this century of up to 0.6 K is primarily a result of worldwide burning of fossil fuels. The purpose of this article is to show that the statements of this skeptical school of thought need to be critically analyzed (and in some cases refuted) in the light of current understanding of the planetary system that determines our climate. There is also another school of thought that agrees about the reality of present and future global warming| and claims that this will be beneficial for most of mankind and that it should be encouraged. The policy implications of the latter view are in many respects similar to those of the group that are not convinced that a significant global warming will occur. Both schools of thought argue against taking immediate steps to slow the climate change.
3597,1991,2,3,REVISED PROJECTION OF FUTURE GREENHOUSE WARMING,For the Intergovernmental Panel on Climate Change (IPCC) report 1| using a simple climate/ocean model| we made projections of the greenhouse warming to 2100. Projections were made for four greenhouse-gas scenarios| whose radiative effects in 2100| expressed in terms of an equivalent amount of CO2| ranged from 2 to 5.5 times the pre-industrial CO2 concentration. The projected global warming in 2100 for these scenarios| relative to 1990| ranged from 0.62-2.31-degrees-C for the minimum assumed CO2-doubling temperature sensitivity| DELTA-T2x = 1.5-degrees-C| to 1.61-5.15-degrees-C for the maximum sensitivity DELTA-T2x = 4.5-degrees-C. Here we broaden these projections to include a recently suggested lower sensitivity| DELTA-T2x = 0.5-degrees-C. We also revise all projections by prescribing| using the results of our analysis of simulations by a coupled atmosphere-ocean general circulation model| a lower value for a key parameter of the simple ocean model| II| which indicates the warming of the polar ocean relative to the warming of the non-polar ocean. We find that| for any value of DELTA-T2x| the atmospheric temperature increases more rapidly with time as a consequence of the reduction in II. We also find that a delay of ten years in initiating a 20-year transition from the IPCC 'business-as-usual' scenario to any other IPCC scenario has only a small effect on the projected warming in 2100| regardless of the value of DELTA-T2x. This indicates that the penalty for a 10-year delay is small. 3517,1991,4,3,SEA-LEVEL AS AN INDICATOR OF CLIMATE AND GLOBAL CHANGE,This paper discusses the difficulties in predicting future global sea level rise. It also examines the problems involved in determining a reliable global sea level trend over the past century from historical water level records and| specifically| whether the apparent recent rise can be attributed to global warming due to the accumulation of greenhouse gases. The paper also discusses the importance of interannual-to-decadal sea level variation and its role in helping to understand climate variations such as El Nino Southern Oscillation and the accompanying global effects via teleconnection.
3614,1991,2,3,SENSITIVITY OF OXIDANT CONCENTRATIONS ON CHANGES IN UV-RADIATION AND TEMPERATURE,Depletion of the stratospheric ozone layer could result in increasing u.v. radiation at ground level. Increasing concentrations of greenhouse gases could result in increasing temperature. The response of boundary layer chemistry on increases in energy| in the form of increasing surface temperature or increasing u.v. radiation| will be an increased photochemical reactivity. In this paper we present the results of a model study on the sensitivity of episodic and long-term averaged ozone and oxidant (Ox| sum of O3 and NO2) concentrations on changes in temperature and u.v. radiation. Ground level ozone and oxidant concentrations are calculated for summer 1989 by means of a Lagrangian long-range transport model for a receptor point in the central part of The Netherlands. For a 10% decrease in ozone column density and a 10% increase in surface temperature (on average DELTA-t = 1.6-degrees-C) the increase in O3 and O(x) 98 percentile value is about 2.7%. The additional ozone production will increase the number of exceedences of threshold values; this may lead to greater human exposures during episodes. The calculations for the reference emission situation resulted for the period 1 May-1 October 1989 (total 3672 h) in 56 observations of 1-h averaged O3 concentrations which exceed the level of 75 ppb; in one case the O3 concentration exceeds 100 ppb. In the sensitivity calculations with increased temperature and reduced ozone column these numbers increase to 72 h (+29%) and 6 h (+600%)| respectively. A possible increase in natural VOC emissions from forests due to a global warming may further enhance the number of exceedences. 3627,1991,3,2,SOLAR POWER SATELLITES - ENERGY-SOURCE FOR THE GREENHOUSE CENTURY,Energy is needed to produce wealth| and an increasing world population will need increasing amounts of energy to improve its standard of living. Through the use of a carbon cycle model| it is shown that continued reliance on fossil fuels will cause a global greenhouse warming. An energy-CO2-economics model is used to project future demand for fossil-fuel-generated energy. When this demand is compared with the fossil fuel use that is permissible if a global warming is to be avoided| a shortfall in energy becomes evident. Terrestrial photovoltaics| nuclear fission| nuclear fusion| and the solar power satellite (SPS) are examined as means of making up this energy shortfall. On comparing these technologies| the SPS appears to be the most feasible means of providing the required energy and preventing a global warming. Laser| 2.45 GHz| and 35 GHz SPS technologies are intercompared| and results indicate that the 2.45 GHz technology remains the most feasible SPS option. 2133,1991,2,4,SOME CONSEQUENCES OF LONG-TERM HUMAN IMPACTS ON ECOSYSTEMS,Regional- and global-scale environmental problems potentially can affect North and South Temperate Zone ecosystems differently because of regional differences in population density and growth| and use of resources. Consideration is given to global climate change and various components of global and regional| environmental change| including atmospheric ozone| acid rain| toxic metals and pesticides| eutrophication| and erosion. Acid rain is a serious environmental problem in industrialized and urbanized regions of the Northern Hemisphere. Long-term data from the Hubbard Brook Experimental Forest in New Hampshire| USA| provide a temporal dimension for this problem. Currently atmospheric deposition of sulfur in the northeastern United States exceeds by three to six times limits established to protect sensitive ecological systems| whereas in southern Chile current atmospheric deposition of sulfur is less than these acceptable limits. Developed| and particularly developing| countries throughout the world face serious questions of resource management as human populations increase| and if regional- and global-scale pollution were to increase accordingly.
3579,1991,4,4,SOURCES AND SINKS OF METHANE IN SWEDEN,Sources of methane in Sweden emit about 3.0 Tg . yr-1 to the atmosphere| corresponding to about 0.6% of the estimated global flux. Net flux| estimated by deducting amounts taken up by boreal forest soils could be about 10% lower. Wetlands are by far the largest source (2.2 Tg . yr-1| 73% of total followed in decreasing order by landfills (0.34 Tg.yr-1| 11%)| coastal areas and freshwater bodies (0.31 Tg . yr-1| 10%) animal and manure (0.14 Tg . yr-1| 5%) and combustion processes and leakage of natural gas (0.03 Tg . yr-1| 1%). Man-made wetland disturbances associated with drainage have reduced methane emissions by about 0.29 Tg . yr-1. Human activities have led to moderate increases in methane emissions from freshwater bodies and coastal waters. Other sources of methane emissions are almost exclusively of anthropogenic origin. The influence of global warming on the methane fluxes is briefly discussed. 3549,1991,2,3,SOUTH-AFRICAN SEA-LEVEL MEASUREMENTS IN THE GLOBAL CONTEXT OF SEA-LEVEL RISE,Examination of historical instrument records of temperature and sea level in tectonically stable areas around the world have shown a global warming of about 0.5-degrees-C and a eustatic rise in sea level of between 10 mm and 15 mm/decade over the last century. Sea-level measurements around South Africa are available only from 1959 onwards and their analyses show trends comparable with global trends of sea-level rise. The best long tide gauge record is from Port Nolloth and shows a rise in relative sea level over the period 1960 to 1988 of 12.3 mm/decade at the 95% confidence level. Comparison with an Argentinian relative sea-level curve indicates some basin-wide coherence in water levels on approximately a 5-year time scale. South African sea surface temperatures (SST) also show historical increases comparable with other global SST estimates. On the basis of agreement between historical South African and globally estimated trends| predictions of future sea-level rise around South Africa are adopted from globally modelled studies. Sea level in South Africa is expected to rise by approximately 20 cm within the next 40 years and may increase further to up to 100 cm by the end of the next century. The rate of increase of atmospheric concentrations of greenhouse gases is shown to be the best indicator of continued sea-level rise. 3596,1991,4,3,SOUTHERN-HEMISPHERE CLIMATE SCENARIOS,There is little doubt that between now and 2050 Earth faces global warming and other changes in climate unprecedented in magnitude since the end of the last glaciation some 10 000 years ago. Predicting the exact nature of that change is| however| difficult. Arguments from palaeoclimatic analogues| comparisons of recent warm versus cool years| physical reasoning and computer simulations are all subject to error and uncertainty. This is more so in the relatively less well understood climate system of the Southern Hemisphere| and at the local and regional scale| than in the Northern Hemisphere and at a zonally averaged scale. Nevertheless some broad features can be described with some confidence| and we can at least identify some of the major uncertainties and processes which we need to understand better. Increased poleward penetration of the subtropical monsoonal regimes is likely| and tropical cyclones may also occur at higher latitudes than at present. The role of the oceans| especially at high southern latitudes and in the tropics| and effects which may change with time as greenhouse gas concentrations gradually increase ('transient' effects) are particularly important and uncertain in the Southern Hemisphere. We know enough to declare the urgency of slowing down and eventually limiting the greenhouse effect. However| more research is needed to guide decision makers and planners at the local and regional level as they try to cope with those climatic changes which are unavoidable. Regional cooperation is essential to make the best use of the research and planning facilities available. 2160,1991,2,4,TEMPERATURE EFFECT ON GROWTH AND DEVELOPMENT OF COTTON DURING THE FRUITING PERIOD,Cotton (Gossypium hirsutum L.) requires warm days and relatively warm nights for optimum growth and development. However| in many areas of the cotton belt| sub- and super-optimal temperatures frequently occur| both early and late in the season| resulting in altered growth and development. The purpose of this research was to quantify plant responses to temperature| so that these responses could be incorporated into plant growth models used to manage cotton crops. Plants| initially grown out of doors in pots| were moved into sunlit| temperature-controlled growth chambers 5 d prior to initial bloom. Growth and development were studied in 20/10| 25/15| 30/20| 35/25| and 40/30-degrees-C day/night temperature regimes from initial bloom. Temperature significantly affected phenology| leaf expansion| internode elongation| biomass production and the partitioning of assimilates to different plant parts. Optimum temperature for biomass production was 30/20-degrees-C| with 40 and 50% less biomass at 20/10 and 40/30-degrees-C| respectively. By 49 d after initial bloom| 13| 15 and 43% of the biomass had been partitioned to bolls and squares at 20/10| 25/15 and 30/20-degrees-C| respectively| reflecting to some extent slower development at the temperatures lower than 30/20-degrees-C. Above 30/20-degrees-C| most of the squares and bolls were aborted. The growth of the main-stem and its successive leaves at 30/20-degrees-C was rapid initially| but was restricted later due to competition with bolls for available carbohydrates. The quantification of growth and developmental rates over a wider range of temperatures will enable us to predict crop performance if temperature increases as a result of global climate change.
3601,1991,3,3,THE CONFLICT OVER GLOBAL WARMING - THE APPLICATION OF SCIENTIFIC-RESEARCH TO POLICY CHOICES,Sophisticated computer models have been employed by the United Nations Environment Programme's Intergovernmental Panel on Climate Change (IPCC) to assess past variations of world climate and to project possible trends over the next century. Attention has focused on the growing concentration of carbon dioxide (CO2) and other greenhouse gases that contribute to global warming. Critics in scientific and policy professions hold that simulation models are not yet adequate to guide policy decisions. Many western governments dissent from this judgment and insist that a 20% reduction in CO2 emissions should be achieved within 15 years and that remedial policies must be adopted to prevent catastrophic climate change. The proposed remedies range from saving tropical rain forests to forced conservation of energy or taxation of fossil-fuel combustion. A consensus is emerging in the scientific community to endorse a 'no regrets' policy that involves buying various kinds of 'insurance' against future global warming. 2147,1991,2,4,THE ECONOMIC-IMPACT OF CROP LOSSES - A COMPUTABLE GENERAL EQUILIBRIUM APPROACH,The impact of crop losses on the U.S. economy are analyzed using a Computable General Equilibrium (CGE) Model. In doing so| concerns about widespread crop losses due to a global climate change or environmental event are addressed. The CGE approach allows for analysis of the interactions between supply and demand within agricultural markets as well as between these markets and the rest of the economy. The results suggest that policy responses which allow free market pricing signals to determine production mitigate the effects of an event that approximates the drought of 1988.
3565,1991,2,4,THE EFFECT OF POTENTIAL CLIMATIC CHANGES ON THE GEOGRAPHICAL-DISTRIBUTION OF THE PLANT-PARASITIC NEMATODES XIPHINEMA AND LONGIDORUS IN EUROPE,The data collected during the European Plant-Parasitic Nematode Survey which allows relatively detailed maps of the geographical distribution of virus-vector nematodes to be produced are used to analyse the relationship between the distribution of Longidorus elongatus| L. leptocephalus| L. macrosoma and Xiphinema diversicaudatum and the July soil isotherm in Great Britain and Europe. Results indicate a close association between temperature and nematode distribution and allow minimum| maximum and optimum developmental temperatures to be calculated. Predicted future climatic changes and in particular global warming show that nematode problems in northern Europe could intensify by an increase of the existing nematode populations and by the spread of nematodes from the south| but the rate at which this spread occurs is likely to be slow and dependent upon man's activities. 3575,1991,5,3,THE MIDCRETACEOUS SUPER PLUME| CARBON-DIOXIDE| AND GLOBAL WARMING,Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. We developed a carbonate-silicate cycle model to quantify the possible climatic effects of these CO2 releases| utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. We find that CO2 emissions resulting from super-plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern pre-industrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering-rate formulations| this would cause a global warming of from 2.8 to 7.7-degrees-C over today's global mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8-degrees-C to mid-Cretaceous warming. Thus| the combined effects of paleogeographic changes and super-plume related CO2 emissions could be in the range of 7.6 to 12.5-degrees-C| within the 6 to 14-degrees-C range previously estimated for mid-Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20% of the mid-Cretaceous increase in atmospheric CO2. 3548,1991,2,3,THE POSSIBLE DYNAMIC-RESPONSE OF NORTHERN FORESTS TO GLOBAL WARMING,Increasing greenhouse-gas concentrations in the atmosphere are expected to produce maximum warming in high latitudes| displacing the potential boreal forest zone of the northern hemisphere far to the north. We analyse the implications of this shift for forest composition and biomass dynamics across the present-day boreonemoral zone in Scandinavia| using a forest succession model that includes a generalized disturbance regime and realistic climatic effects on species' regeneration and growth. Temperature increases in the range of 2-4 K in summer and 5-6 K in winter| typical of simulated CO2 doubling effects| force the boreonemoral zone > 1000 km northward from central Sweden where dominance passes from Picea (spruce) to Fagus (beech)| Quercus (oak) and Pinus (pine) over 150-200 years. Simulated increases of 175-250 mm in annual precipitation are required to counteract drought| which would otherwise reduce forest biomass and increase the representation of the more drought-tolerant species. The simulated forest dynamics are the net result of individualistic responses of species to different aspects of climate| modulated by successional processes that are on the same time scale as human impacts on climate. 2163,1991,2,3,THE POTENTIAL IMPACTS OF CLIMATE CHANGE ON THE GREAT-LAKES,Global climate change could have a significant impact on the Great Lakes. A number of studies of the potential effects of climate change on the Great Lakes were commissioned by the U.S. Environmental Protection Agency| using common scenarios of global warming derived mainly from general circulation models. These studies found that a doubling of carbon dioxide concentrations in the atmosphere could eventually lower Great Lakes water levels by 0.5 to 2.5m; reduce ice cover by 1 to 2 1/2 months; lengthen shipping seasons while increasing shipping and dredging costs; reduce dissolved oxygen levels in shallow lake basins; and increase fish productivity. Measures should be taken in the near future to anticipate many of these impacts and mitigate their effects or avoid costly political issues.
3602,1991,3,4,THE ROLE OF PASSENGER TRANSPORT IN CO2 REDUCTION STRATEGIES,The implications of CO2 reductions are nowhere more profound than in the transport sector. In the light of the 60% cut in emissions recommended by the Intergovernmental Panel on Climate Change| transport must find ways of using less fossil fuel. Car fuel economy has considerable short-term potential for saving energy| but requires incentives and regulations. Alternative fuels| if selected carefully| can also reduce greenhouse emissions. But CO2 savings may be out-stripped by projected increases in traffic| and restrictions are needed to curb this growth. CO2 abatement measures will be ineffective in isolation| and a successful strategy will contain a variety of approaches| encompassing both short- and long-term policies. 3631,1991,3,3,THE UNITED-STATES-DEPARTMENT-OF-ENERGY BIOFUELS RESEARCH-PROGRAM,Biomass encompasses agricultural and forestry residues| woody and herbaceous energy crops| municipal solid waste| and underutilized traditional forests. The contribution of biomass to the nation's energy supply stands at 3.1 quads per year and is continuing to grow. Increasing our use of fuels derived from biomass can improve air quality| mitigate global warming| reduce dependency on foreign oil imports| and strengthen a weak farm economy. The U.S. Department of Energy's (DOE) Biofuels and Municipal Waste Technology Program has focused mainly on liquid fuels such as ethanol| methanol| biocrude-derived gasoline| and plant-oil-derived diesel fuel| with some emphasis on gaseous fuels such as biogas. Researchers have improved the economics of the wood to ethanol process to approximately $1.35/gal by developing a method to ferment ethanol from the xylose fraction of wood with greater than 70% efficiency. The program goal of $0.60/gal would provide ethanol at a competitive cost without tax credits. DOE has increased the emphasis on cooperative ventures with industry and is developing plans for a cost-shared project to scale up gasification technologies for both syngas and methanol fuel production testing. Development of successful methods for cleaning and conditioning the raw syngas from the gasifier is expected to reduce methanol costs from $0.75/gal to $0.55/gal. Scientists have made substantial progress in testing process concepts for hydrotreating and zeolite catalyst upgrading of pyrolysis oils to produce gasoline. The cost of gasoline from biomass by this process is currently projected at $1.60/gal with a goal of $0.85/gal. With adequate research and development investments| biofuels can have a much greater impact on the liquid transportation fuels sector in the future| even without legislation or federal regulations to stimulate the industry. Therefore| biofuels costs are projected to be competitive with oil costs at $25-$30/bbl within the next 5-10 years; however| the development time frame depends on the research and development investment level. 2152,1991,3,4,THE USE OF ANALOGIES IN FORECASTING ECOLOGICAL AND SOCIETAL RESPONSES TO GLOBAL WARMING,Until computer modeling systems are able to forecast the regional impacts of a global climate change| scientists and nonscientists alike will find analogies useful for understanding how ecosystems and societies might respond to such change. But analogies must be used with care lest they be misapplied to justify a particular policy agenda.
3557,1991,2,4,THE VIGIL NETWORK - A MEANS OF OBSERVING LANDSCAPE CHANGE IN DRAINAGE BASINS,Long-term monitoring of geomorphic| hydrological| and biological characteristics of landscapes provides an effective means of relating observed change to possible causes of the change. Identification of changes in basin characteristics| especially in arid areas where the response to altered climate or land use is generally rapid and readily apparent| might provide the initial direct indications that factors such as global warming and cultural impacts have affected the environment. The Vigil Network provides an opportunity for earth and life scientists to participate in a systematic monitoring effort to detect landscape changes over time| and to relate such changes to possible causes. The Vigil Network is an ever-increasing group of sites and basins used to monitor landscape features with as much as 50 years of documented geomorphic and related observations. 3580,1991,2,4,THERMAL RESPONSE OF THE ACTIVE LAYER TO CLIMATIC WARMING IN A PERMAFROST ENVIRONMENT,Global warming is occurring| the only question is what will be the magnitude of the temperature change and the temporal and spatial distribution? Existing models predict that the greatest change from present climatic conditions will happen in the polar regions. In the Arctic| continuous permafrost exists and climatic warming could have severe consequences. In this paper the consequences of global warming on the active layer are examined. Soil temperature data were collected over a four-year period at a field site near Toolik Lake| Alaska. A finite-element| two-dimensional| heat conduction model with phase change was used to predict soil temperatures at the site. After verification that the model could be used with confidence to predict the soil thermal regime| various climatic warming scenarios were used as inputs to estimate the thermal response for the next fifty years. The impact of climatic warming on the thickness of the active layer is reported. 3559,1991,2,4,TIDAL-CREEK EXTENSION AND SALTWATER INTRUSION IN NORTHERN AUSTRALIA,Low-lying Holocene coastal plains supporting freshwater wetlands are often close to or even below the level reached by the highest tides. The vulnerability of such freshwater systems to saltwater intrusion will increase should the sea level rise as a consequence of global warming. In areas with a large tidal range| one of the main processes inducing a reversion to saltwater influence is likely to be the rapid extension of tidal-creek systems. This is demonstrated with an example from the coastal plains of the Mary River in northern Australia| where tidal-creek systems have extended more than 30 km inland in 50 years| invading freshwater wetlands and destroying associated vegetation over an area of at least 17 000 ha. Networks have grown at an exponential rate through a combination of headward extension along main channels and tributary development. Large tidal range| very small elevational differences over the plains| the presence of incompletely infilled paleochannels| and uncontrolled feral buffalo have been major factors contributing to the rapid rate of expansion. 3564,1991,4,3,TIME| FREQUENCY AND SPACE GEODESY - IMPACT ON THE STUDY OF CLIMATE AND GLOBAL CHANGE,The science of time and frequency metrology has enabled the development of space geodetic systems that are being applied to the high accuracy tracking of new space-based instruments that have begun one of the most important investigations of the Earth ever undertaken. The accumulation of anthrogenic gases in the Earth's atmosphere| especially carbon dioxide| is likely to lead to global atmospheric warming. Warming may alter atmospheric circulation| rainfall patterns| and the melting of polar ice caps| which will cause sea level rise and pose a threat to our survival unprecedented in all of recorded history. These new instrument sets and methodologies have been designed to be appropriate for many years to decades of operation in order to measure the open ocean circulation and sea level as an indicator of global warming and will be a vital means for assessing the effectiveness of future remedial actions. The question is whether sea level is actually rising| and if so| at what rate? There are a wide variety competing instrument related artifacts and "geophysical signals" in the land and ocean data| all of which must be measured| modeled and removed before sea level signal can be completely distinguished. The issues of time and frequency are tied into all of these space geodetic techniques| from the Cesium and Rubidium oscillators aboard Global Positioning System (GPS) satellites| to the epoch time and time interval measurements of satellite laser ranging (SLR) and hydrogen maser references used in very long baseline interferometry (VLBI). Without the developments of these time and frequency technologies| none of these space geodetic methods would be possible. 3528,1991,3,3,TOWARD CLIMATE CONVENTIONS SCENARIO ANALYSIS FOR A CLIMATIC PROTECTION POLICY,The 1980s have seen an unprecedented growth in awareness of the problem of climatic change. The 1990s will be the critical decade during which collective concern must be turned into concerted action through global Climate Conventions and related Protocols. This article proposes such a strategy with the following elements: setting of a warming ceiling and a rate of change per decade; development of emission scenarios which come close to the set limits using climate modeling; allocation of emission shares by nation; assessment of emission reduction potential by gas| source| measure and nation; development of national emission reduction plans; agreement| implementation and supervision of such plans; establishment of a climate fund. This study addresses the first element of the strategy by making extensive use of model-based climate scenario analysis. The results of this analysis will help identify emission reduction measures which could limit the mean global surface warming to approximately 2 K in 2100 over the preindustrial level and restrict the average rate of global warming to about 0.1 K per decade. The effectiveness of these scenarios is assessed using a one dimensional (1-D) climate model from 1860 to 2100. The results of this research will help widen the scope for a more flexible climate protection policy. 3578,1991,4,3,UPPER LIMIT FOR SEA ICE ALBEDO FEEDBACK CONTRIBUTION TO GLOBAL WARMING,Two versions of the National Center for Atmospheric Research Community Climate Model (CCM) are used to calculate the increase in solar energy absorbed by the Earth-atmosphere system if all sea ice on the planet were to melt. The increase in solar energy is determined at several time points in the seasonal cycle by brief integrations of the models with the surface albedo of sea ice changed to that of open ocean; temperature| cloudiness| and other climate parameters are unchanged during the short integrations| so that our results isolate the climatic effect of sea ice albedo changes in the absence of other processes and feedbacks. (In particular| we do not include the effects of removing the insulation between ocean underneath sea ice and the atmosphere above it.) We find that the globally and annually averaged enhancement of absorbed solar flux due to removal of sea ice is 2-3 W m-2; a simple calculation indicates that most of the difference between model versions is due to differences in the surface albedo of sea ice. About half the albedo reduction at the surface is masked at the top of the atmosphere by clouds| even though the CCM versions we use tend to underestimate cloudiness. Our upper limit is significant compared to the direct radiative forcing of a doubling of atmospheric carbon dioxide| but it suggests that for greenhouse gas warming equivalent to doubling of CO2 or greater| the sea ice albedo feedback is likely to be smaller than from water vapor and potentially that from clouds. 3539,1991,2,4,UPPER TEMPERATURE LIMITS FOR TROUT IN NEW-ZEALAND AND CLIMATE CHANGE,The significance of temperature in determining the northernmost limit of trout in New Zealand is discussed| and the river temperature records available suggest that high winter temperatures| rather than high summer temperatures are involved. The predicted climate changes consequent on increased concentrations of atmospheric gases| are used to predict changes in trout distribution. A 1.5-degrees-C increase is likely to result in a contraction of the distribution of brown trout in northern areas| but the effects elsewhere on brown trout would be limited. A 3-degrees-C increase is likely to eliminate both species from northern latitudes| while heat stress could alter distributions of both species throughout the country. The possibilities of genetic responses to the changes are discussed. 3562,1991,4,4,USE OF COSMOGENIC S-35 TO DETERMINE THE RATES OF REMOVAL OF ATMOSPHERIC SO2,GASEOUS sulphur dioxide supplied to the atmosphere is removed principally by three processes: direct scavenging in precipitation| oxidation to aerosol sulphate with subsequent deposition by vertical and horizontal precipitation| and 'dry' deposition| primarily on the surface of vegetation. The rates of these removal processes| which vary with environmental conditions| must be known in order to understand the fate of SO2 and the concentration and distribution of aerosol sulphate 1-3. The latter is thought to play a part in the heat balance of the lower troposphere 4| and is thus relevant to the issue of global warming. Approaches to this problem using field observations 5|6 have not given consistent or uncontested results. We report here the use of cosmogenic S-35 (half-life 87.2 days) as a way of determining the time constants for oxidation| in-cloud scavenging and aerosol deposition. Our method involves determining S-35 levels in gaseous SO2| aerosol sulphate and precipitation. If these seasonally and regionally variable time constants can be applied to terrestrially produced SO2| S-35 measurements could provide an independent method for studying the fate Of SO2 in the atmosphere as a function of time and place. 2165,1991,2,3,VEGETATION AND WILDLAND FIRE - IMPLICATIONS OF GLOBAL CLIMATE CHANGE,Climate| vegetation| and fire are interrelated so that any change in one will affect the others. Increases in greenhouse gases| especially carbon dioxide| are expected to increase average surface temperatures and alter precipitation patterns. These changes will alter numerous biochemical processes of vegetative communities. Changes in growth rates| carbon allocation patterns| nutrient cycling| and competitive interactions will lead to direct changes in the structure and species composition of many plant communities. Major shifts in vegetation zones will occur in many regions. Climate change will affect fire potential by influencing the frequency and severity of weather favorable for fire. Climate-driven changes in the structure and composition of plant communities will also affect fire potential by altering the physical and chemical properties of fuels. Changes in timing and severity of fire will modify the rate at which communities respond to climate change. This in turn will alter fuel properties| further modifying fire potential. Changes in fire regimes will directly affect the chemistry of the atmosphere by modifying vegetation and emitting gases and particulate matter. The expected rate and magnitude of these changes raises questions for the continued integrity| vitality| and stability of current ecosystems.
2158,1991,3,4,WHAT ROLE CAN NUCLEAR-POWER PLAY IN MITIGATING GLOBAL WARMING,Although nuclear energy is a low CO2 energy system| it is not a very efficient tool for rapidly reducing carbon emissions. Global climate change does not justify a considerably increased global nuclear programme for the next two to three decades. Even if for other political or socioeconomic reasons such an intensive global nuclear programme were initiated| its impact on CO2 emissions would be only marginal. This is true irrespective of the costs and feasibilities of alternative emission reduction strategies| such as energy efficiency measures| or the availability of other low CO2 energy supplies.
3705,1992,4,3,A COMPARISON OF AGGREGATE ENERGY DEMAND MODELS FOR GLOBAL WARMING POLICY ANALYSES,This paper compares the treatment of the demand for all fuels (aggregate energy) in 11 models that are being used for analysing the economic and energy-sector impacts of global warming policy. Some models explicitly consider the linkages between the economy and the energy sector (energy-economy models)| while others focus on the energy sector in more detail (energy models). The paper discusses demand model inputs and outputs| time horizon| regional and sectoral disaggregation| energy consumer behaviour| energy using capital stock and energy efficiency improvements| and incorporating uncertainty. 2191,1992,5,4,A DETAILED CHRONOLOGY OF THE AUSTRALASIAN IMPACT EVENT| THE BRUNHES-MATUYAMA GEOMAGNETIC POLARITY REVERSAL| AND GLOBAL CLIMATE CHANGE,A mechanism had been recently proposed to show how an impact event can trigger a geomagnetic polarity reversal by means of rapid climate cooling. We test the proposed mechanism by examining the record from two high sedimentation rate (8-11 cm/kyr) deep-sea sediment cores (ODP Sites 767 and 769) from marginal seas of the Indonesian archipelago| which record the Australasian impact with well-defined microtektite layers| the Brunhes-Matuyama polarity reversal with strong and stable remanent magnetizations| and global climate with oxygen isotope variations in planktonic foraminifera. Both ODP cores show the impact to have preceded the reversal of magnetic field directions by about 12 kyr. Both records indicate that the field intensity was increasing near the time of impact and that it continued to increase for about 4 kyr afterwards. Furthermore| the oxygen isotope record available from sediments at ODP Site 769 shows no indication of discernible climate cooling following the impact: the microtektite event occurred in the later part of glacial Stage 20 and was followed by a smooth warming trend to interglacial Stage 19. Thus the detailed chronology does not support the previously proposed model which would predict that a decrease in geomagnetic field intensity resulted from a minor glaciation following the impact event. We conclude that the evidence for a causal link between impacts and geomagnetic reversals remains insufficient to demonstrate a physical connection.
2195,1992,4,4,A DETERMINISTIC APPROACH TO THE VALIDATION OF HISTORICAL DAILY TEMPERATURE AND PRECIPITATION DATA FROM THE COOPERATIVE NETWORK,It is widely known that the TD3200 (Summary of the Day Cooperative Network) database held by the National Climatic Data Center contains tens of thousands of erroneous daily values resulting from data-entry| data-recording| and data-reformatting errors. TD3200 serves as a major baseline dataset for detecting global climate change. It is of paramount importance to the climate community that these data be as error-free as possible. Many of these errors are systematic in nature. If a deterministic approach is taken| using empirically developed criteria| many if not most of these errors can be corrected or removed. A computer program utilizing Backus Normal Form structure design and a series of chain-linked tests in the form of encoded rules has been developed as a means of modeling the human subjective process of inductive data review. This objective automated correction process has proven extremely effective. A manual review and validation of 138 stations of a 1300-station subset of TD3200 data closely matched the automated correction process. Applications of this technique are expected to be utilized in the production of a nearly error-free TD3200 dataset.
3716,1992,3,4,A GEOLOGICAL PERSPECTIVE ON GLOBAL WARMING AND THE POSSIBILITY OF CARBON-DIOXIDE REMOVAL AS CALCIUM-CARBONATE MINERAL,Nature removes carbon dioxide from the atmosphere through photosynthesis| and by forming carbonate minerals. Following Nature's example| carbon dioxide should not be regarded as a waste| but as a resource from which useful products can be made. Highly concentrated| calcium-rich brines are commonly found associated with subsurface salt deposits. By bringing together the energy and chemical industries| it may be possible to use these brines to lock up carbon dioxide| while at the same time producing calcium carbonate| hydrochloric acid and a variety of other chemical-industrial commodities. 2194,1992,4,4,A GLOBAL INVENTORY OF VOLATILE ORGANIC-COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES,As part of an effort to assess the potential impacts associated with global climate change| the U.S. Environmental Protection Agency's Office of Research and Development is supporting global atmospheric chemistry research by developing global scale estimates of volatile organic compound (VOC) emissions (excluding methane). Atmospheric chemistry models require| as one input| an emissions inventory of VOCs. Consequently| a global inventory of anthropogenic VOC emissions has been developed. The inventory includes VOC estimates for seven classes of VOCs: paraffins| olefins| aromatics (benzene| toluene| xylene)| formaldehyde| other aldehydes| other aromatics| and marginally reactive compounds. These classes represent general classes of VOC compounds which possess different chemical reactivities in the atmosphere| The technical approach used to develop this inventory involved four major steps. The first step was to identify the major anthropogenic sources of VOC emissions in the United States and to group these sources into 28 general source groups. Source groups were developed to represent general categories such as "sources associated with oil and natural gas production" and more specific categories such as savanna burning. Emission factors for these source groups were then developed using different techniques and data bases. For example| emission factors for oil and natural gas production were estimated by dividing the United States' emissions from oil and gas production operations by the amount of oil and natural gas produced in the United States. Multiplication of these emission factors by production/consumption statistics for other countries yielded global VOC emission estimates for specific source groups within those countries. The final step in development of the VOC inventory was to distribute emissions into 10-degrees by 10-degrees grid cells using detailed maps of population and industrial activity. The results of this study show total global anthropogenic VOC emissions of about 110|000 Gg/yr. This estimate is about 10% lower than global VOC inventories developed by other researchers. The study identifies the United States as the largest emitter (21% of the total global VOC)| followed by the (former) USSR| China| India| and Japan. Globally| fuel wood combustion and savanna burning were among the largest VOC emission sources| accounting for over 35% of the total global VOC emissions. The production and use of gasoline| refuse disposal activities| and organic chemical and rubber manufacturing were also found Lo be significant sources of VOC emissions.
3643,1992,4,4,A MODEL-BASED APPROACH TO THE CALCULATION OF GLOBAL WARMING POTENTIALS (GWP),The Global Warming Potential (GWP) of greenhouse gas emissions can be defined as a greenhouse pendant to the Ozone Depleting Potential (ODP). Global Warming Potentials are calculated for the most important greenhouse gases (CO2| CH4| CO| N2O| CFC-11| CFC-12| CFC-13| CFC-14| CFC-113| CFC-114| CFC-115| CFC-116| CF3Br| CCl4| CH3CCl3| and HCFC-22) and eight potential CFC substitutes using the integrated climate assessment model IMAGE. Two different methods are presented for the calculation of GWP values using IMAGE: one that generates equivalent pulses for all greenhouse gases| and an iterative trace-back method which calculates the different pulses required to achieve an identical global temperature increase for all greenhouse gases. In addition the influence of the emission scenario used is tested when determining GWPs; it is demonstrated that GWPs are indeed scenario-dependent| so the choice of the underlying emission scenario is important. Finally| the GWPs calculated using these methods are compared with GWPs that have been published previously. It appears that our GWP estimates are substantially higher than the IPCC estimates| which can be explained by the fact that our carbon cycle model has a balanced global carbon budget. This results in lower projections of future atmospheric carbon dioxide compared with the IPCC projections. 3774,1992,4,3,A MODELING STUDY OF THE NORTH-ATLANTIC WITH EMPHASIS ON THE GREENLAND-ICELAND-NORWEGIAN SEA,This essay presents the results of a modeling study that addresses the circulation and convection of ocean currents. A possible change in the global climate due to human-induced increase of atmospheric CO2 and other greenhouse gases is one of the major environmental challenges in our time. In order to get more insight into this problem| one needs to better understand the various components of the climate system and how they interact. Due to the large heat capacity of the global ocean| the magnitude| delay| and regional distribution of a potential global warming are to a large extent determined by exchanges of heat between the upper ocean and the world's deep ocean. An important process in this regard is deep water formation due to convection. The North Atlantic and the Greenland-Iceland-Norwegian Sea are particularly important regions for this process. Major parts of the circulation in this area are simulated by a coupled ke-ocean model that also includes the entire Arctic Ocean. 3660,1992,2,4,A NEW SUBSPECIES OF CHAMAEA-FASCIATA (WRENTIT) FROM OREGON (AVES| TIMALIINAE),Geographic variation in plumage color of Chamaea fasciata (Wrentit) from northern California and southern Oregon is related to climate. A new subspecies| Chamaea fasciata margra| is described from a disjunct population of southern interior Oregon. Colonization of C. fasciata in interior Oregon was perhaps from birds crossing coniferous forests via isolated balds of Ceonothus. Recent increases of Wrentits in interior Oregon may be in response to habitat alterations (deforestation| fires) and concurrent global warming. 3723,1992,3,4,A TECHNOLOGY FOR REDUCTION OF CO2 EMISSIONS FROM THE TRANSPORTATION SECTOR,By sequestering byproduct carbon and replacing petroleum fuels with biomass-derived methanol| the Hydrocarb process can nullify the net effect of CO2 emissions from motor vehicles. This paper gives a preliminary assessment of the process which indicates that substantially more fuel energy could be produced--and at lower cost--than other current options for mitigating CO2 from mobile sources. The incremental cost of eliminating net CO2 emissions is estimated at $0.05 per gallon (3.78 liters) of gasoline displaced by methanol. About 80 percent reduction should be achievable at no incremental cost. 3685,1992,4,4,ABSORPTION-COEFFICIENTS OF CFC-11 AND CFC-12 NEEDED FOR ATMOSPHERIC REMOTE-SENSING AND GLOBAL WARMING STUDIES,Spectral absorption coefficients (or absorption cross-sections) k(v) (cm-1 atm-1) of CFC-11 and CFC-12 have been measured in the spectral region (8-12-mu-m) known as the atmospheric window. Data obtained with a grating spectrometer| which has wide spectral coverage and adequate spectral resolution (0.4 cm-1)| are compared with the so-called NCAR cross-sections that have recently been introduced into the HITRAN Tape. We have also performed measurements| at various temperature-pressure combinations which are chosen to represent tangent heights (as in solar-occultation experiments) or layers in the atmosphere| of the k(v) of CFC-12 in the 921 and 923 cm-1 Q-branches and at 924.1| 927.6| 931.6 93 5.0 and 1106 cm-1 with the Doppler-limited spectral resolution (approximately 10(-4) cm-1) of a tunable-diode laser spectrometer. The latter are especially well suited for atmospheric remote sensing| while the grating spectra are useful in global warming studies. The effects of temperature and pressure on the spectral absorption coefficients are discussed. 2170,1992,2,4,ACCRETION RATES OF LOW INTERTIDAL SALT MARSHES IN THE PACIFIC-NORTHWEST,Salt-marsh accretion rate was investigated at sites that spanned a gradient in relative rate of sea-level rise in Washington and Oregon. Mean accretion rate over all sites was 3.6 mm yr-1 (95% CI = 2.4 to 4.8 mm yr-1)| which exceeded present mean sea-level-rise rate (1.3 mm yr-1; sd = 0.6). However| a mean rise rate of 5.5 mm yr-1 (sd = 1.9) predicted by a moderate sea-level-change scenario to occur by the year 2050 exceeds mean accretion rate. Marshes with adequate sediment input seemed to have the capacity to keep pace with an increased sea-level-rise rate. Lowest accretion rates were recorded at sites with the least sediment supply. Accretion rate showed a weak negative correlation with sediment organic matter (measured as volatile solids) and marsh standing stock. The data suggest that moderate and high rise-rate scenarios would threaten the existence of salt marshes in the region in the absence of increased sediment supply. A better understanding is required of marsh accretion and predicted rate of sea-level rise to refine predictions of the effects of sea-level rise on Pacific Northwest salt marshes.
3665,1992,3,2,ALTERNATIVE ENERGY-RESOURCES - A KENYAN PERSPECTIVE,Kenya's heavy dependence on petroleum has had an adverse effect on its economy| making it difficult to achieve its development goals. Furthermore| the use of fossil fuels is accompanied by emissions of large quantities of carbon dioxide into the atmosphere-a process that is enhancing the greenhouse effect and subsequent global warming and climate change. This article gives an analysis of the Kenya's current energy scene and discuses its alternative energy resources. Although renewable energies are at present not viable substitutes for oil| the development and exploitation of these energy resources will not only reinforce conservation measures but also promote new trends in technology development. 3747,1992,2,4,AN ASSESSMENT OF A LATITUDE-TEMPERATURE INDEX FOR PREDICTING CLIMATE SUITABILITY FOR GRAPES IN EUROPE,The climatic suitability of wine grape classes in Europe was mapped using a latitude-temperature index. It was found necessary to superimpose a constraint based on a minimum temperature of the coldest month of -3-degrees-C to exclude those areas where winters are too severe for vine survival. The index| combined with this constraint| proved a useful indicator of current climatic potential of wine grapes. A sensitivity analysis| using arbitrary adjustments to temperature| suggested that even a 1-degrees-C warming could lead to a significant expansion in potential of viticulture. More critical examination| using GCM projections of global warming| and more site or region specific studies are recommended. 3697,1992,2,4,AN ASSESSMENT OF GLOBAL WARMING STRESS ON CARIBBEAN CORAL-REEF ECOSYSTEMS,There is evidence that stress on coral reef ecosystems in the Caribbean region is increasing. Recently numerous authors have stated that the major stress results from "abnormally high" seasonal sea surface temperatures (SST) and have implicated global warming as a cause| stating that recent episodes of coral bleaching result therefrom. However| an analysis of available SST data sets shows no discernible warming trend that could cause an increase in coral bleaching. Given the lack of long-term records synoptic with observations of coral ecosystem health| there is insufficient evidence available to label temperatures observed in coincidence with recent regional bleaching events as "abnormally" high. 3745,1992,2,2,AN EVALUATION OF GLOBAL WARMING AND ITS IMPACT,Energy balance model has been calculated to assess the magnitude of the average global warming by the middle of the next century. It is shown that an increase in temperatures by about 4 K by the year 2050 as compared to the pre-industrial era (approximately 1800 AD) could result from the projected growth of atmospheric concentrations of major greenhouse gases i.e. carbon dioxide| methane| nitrous oxide and chlorofluorocarbons (CFCs). The changes in global warming are considered for different scenarios including the proposed regulatory measures on the use of CFCs. It is shown that even though the adoption of the revised Montreal Protocol will reduce the global warming due to CFCs by almost 50%| the projected overall global rise in temperature will still be about 2.7 K by the year 2050. The possible climatic impacts of the global warming on a few biogeophysical parameters are found to be alarming. Unless prompt action is taken to control the emission fluxes of other major greenhouse gases on lines similar to CFCs| the consequences may be severe for life on earth. 3679,1992,3,3,AN IMPROVED PROCESS FOR CONVERTING CELLULOSE TO ETHANOL,An improved process for converting cellulose to ethanol bas been developed. Significant features are: (a) the use of concentrated hydrochloric acid at moderate temperatures with mechanical action to hydrolyze the cellulose to glucose in quantitative yield| (b) recovery of the acid from the hydrolyzate by electrode to provide concentrated sugar solutions for fermentation; and (c) continuous fermentation of the sugars combined with continuous distillation of the ethanol produced. When this process is applied to the cellulosic content of municipal solid waste that is unsuitable for recycling and bas zero or negative cost because of high tipping fees the cost of ethanol production is much lower than that of ethanol produced from com. This technology shows promise of ameliorating the solid waste disposal problem while providing fuel alcohol to decrease urban air pollution without contributing to global warming 2197,1992,4,4,AN INTERACTIVE HYBRID EXPERT SYSTEM FOR POLAR CLOUD AND SURFACE CLASSIFICATION,An interactive hybrid expert system is developed to classify polar scenes using AVHRR LAC imagery. A total of 183 spectral and textural signatures axe generated from which the 20 "best" are chosen using the Sequential Forward Selection procedure. These 20 features are used to populate the working memory of the expert system. A probabilistic neural network is used as the inference engine to make probabilistic estimates of class membership. As part of the inference engine| a sophisticated outlier test is performed to provide a measure of classification confidence. During a session| the user is provided with an extensive set of on-screen aids to assist in labelling. The user may modify the knowledge base by adding new samples to existing classes or by including new classes. The expert system provides confidence measures and a distance measure from the proposed class cluster centre. The interactive environment allows the user to test the impact of class labelling upon the knowledge base before new data is entered. For users working with very large datasets and very complex scenes| the integrity of the knowledge base is the primary concern. A bootstrap method is used to validate classification accuracy. On the basis of 100 bootstrap samples| an overall classification accuracy of 87% is achieved| with a standard deviation of 1%. The result is that much more accurate cloud classification in polar regions now can be made| which will aid us in our monitoring of global climate change.
3649,1992,3,3,AN OPTIMAL TRANSITION PATH FOR CONTROLLING GREENHOUSE GASES,Designing efficient policies to slow global warming requires an approach that combines economic tools with relations from the natural sciences. The dynamic integrated climate-economy (DICE) model presented here| an intertemporal general-equilibrium model of economic growth and climate change| can be used to investigate alternative approaches to slowing climate change. Evaluation of five policies suggests that a modest carbon tax would be an efficient approach to slow global warming| whereas rigid emissions- or climate-stabilization approaches would impose significant net economic costs. 3692,1992,4,2,AN OVERVIEW OF GLOBAL WARMING,Temperature records indicate that the global annual mean surface air temperature (referred to as the global temperature) has risen by 0.5-degrees-C since 1840. According to recent general circulation model calculations| by the year 2020 the global mean temperature will have risen to 1.3 to 2.5-degrees-C above the preindustrial (1840) mean. By the year 2070| the range of temperature increase will be 2.4 to 5.1-degrees-C| and sea level will have risen 33 to 75 cm. Measurements from Antarctic ice cores show temperature swings of 4 to 5-degrees-C between ice ages and interglacial periods. Fossil fuel-based energy use through power generation and transportation is viewed as the major cause of the very recent and projected future temperature rise. Recent arguments of scientists and policy makers have increasingly focused on the exact scope of global-scale changes and consequences of the globally rising energy appetite. The question of global warming has become the most important scientific issue. 3703,1992,3,4,ANALYZING THE COST OF AN OECD ENVIRONMENTAL TAX TO THE DEVELOPING-COUNTRIES,Most studies on the global warming issue neglect the impact of proposed measures (eg carbon tax) on the economies of the developing countries in their anlayses. In this paper| an attempt has been made to bridge this gap. By using a standard econometric model| the major (possible) impacts of an OECD carbon tax on developing countries under different policy options were examined. Implementing a carbon tax policy could set serious restrictions to the developmental efforts of the developing countries. The role of non-commercial energy-use vis-a-vis global warming was also investigated. The need for a global perspective when designing effective environmental policies is inevitable. 3654,1992,2,4,APPLICATION OF GEOPROCESSING AND SIMULATION MODELING TO ESTIMATE IMPACTS OF SEA-LEVEL RISE ON THE NORTHEAST COAST OF FLORIDA,Simulation modeling was applied to predict the response of northeast Florida coastal wetlands to future sea level rise due to global warming. Remote sensing and geographic information systems (GIS) were used to develop| manipulate| and synthesize model input including land cover| digital elevation data| and site characteristics data. The SLAMM3 model evaluated the input data to predict responses of coastal wetlands and lowlands to inundation and erosion by sea level rise| and determined transfers from one habitat to another on a cell-by-cell basis. Significant changes were predicted from different scenarios of sea level rise: 0.5 m| 1.0 m| and 1.25 m. The simulations indicated that 31.9 percent and 40.0 percent of wetlands within the study area would be lost with a 1.0 m and 1.25 m sea level rise| respectively| while 6.5 percent would be lost with 0.5 m rise. 2175,1992,4,4,ARABLE LANDS,This paper considers the major types of intensive farming that dominate most of agriculture and examines the effects on biodiversity of certain farming operations. Problems and opportunities for integration of agricultural practices and conservation are approached through a description of different spatial scales. A micro-spatial level examination focuses on field and farm levels. At the field level| farming operations| options available to farmers| and the effects of agricultural options on biological conservation are examined through reference to field preparation| tillage methods| water availability| fertilizers| and harvest methods. At the farm level| field boundaries and size of fields have numerous implications for conservation biology as well as for agriculture| particularly edge effects| buffer zones| and local natural vegetation mosaics. At the regional level| effective management for conservation biology and agriculture needs to consider efforts to increase habitat diversity and patchiness| the interest of urban peoples in recreation and natural areas| and the nature of pest control and management. On the global level| agriculture affects habitats and species survival| contributes to global climate change| ecological and human health| available land for other uses| and composition of plant communities.
3719,1992,4,3,ASSESSING THE SENSITIVITY OF CANADA ECOSYSTEMS TO CLIMATIC-CHANGE,Global warming due to increased concentrations of atmospheric CO2 is expected to be amplified in middle and higher latitudes. Consequently| ecosystems in these latitudes will experience more pronounced climatic variations. This investigation attempts to assess the sensitivity of Canada's ecosystems to climatic change. Potential ecological impacts resulting from global warming are outlined. With this background| the effects of a doubled CO2 climate are applied to a classification model derived from the current ecological setting. Results reveal not only major shifts in ecological boundaries but also changes in the character of these broadly distributed ecosystems. 3709,1992,4,4,ASSESSING THE VALUE OF HISTORICAL TEMPERATURE-MEASUREMENTS,Although some degree of global warming is now recognized| its extent and origin are proving much more complex than was first supposed. In particular| it is difficult to distinguish anthropogenic factors from long-term natural fluctuations. An important source of evidence lies in past recordings of temperature| but the evaluation of these rests on their reliability| which is very variable. This article reviews the accuracy of past records in respect of the instruments| their exposure| and the observers. 3637,1992,2,3,ASSESSMENT| BASED ON A CLIMOSEQUENCE OF SOILS IN TUSSOCK GRASSLANDS| OF SOIL CARBON STORAGE AND RELEASE IN RESPONSE TO GLOBAL WARMING,A soil climosequence in tussock grasslands in South Island| New Zealand| encompassing climates ranging from cold to warm temperate provided a spatial analogue of climate change for investigating the effects of global warming on soil C contents and turnover. Mean annual temperature (T) and annual precipitation (P) ranged from 2 to 10-degrees-C| and 350 to 5000 mm| respectively. Soil C contents were curvilinearly related to T/P across the sequence (r = -0.95| significant at P < 0.01)| indicating that east of the Southern Alps| increased decomposition of organic matter with global warming would provide a positive feedback to further increase atmospheric CO2. This decrease in New Zealand's soil C| estimated to be up to 10% of the current content for a global temperature rise of 0.03 K a-1 to 2050| could contribute about 0.5 x 10(15) g C to the atmosphere over the next 60 years. These conclusions were generally supported by changes in soil C turnover estimated from 'bomb' C-14 enrichment. The unexpectedly slow turnover found for two soils was explained by a 'memory' effect from the former southern beech forest that grew on these soils in prehistoric times. Accumulation of Al-humus under the forest may be responsible for the slow C turnover observed. 2213,1992,2,4,BACTERIAL-GROWTH IN THE COLD - EVIDENCE FOR AN ENHANCED SUBSTRATE REQUIREMENT,Growth responses and biovolume changes for four facultatively psychrophilic bacterial isolates from Conception Bay| Newfoundland| and the Arctic Ocean were examined at temperatures from -1.5 to 35-degrees-C| with substrate concentrations of 0.15| 1.5| and 1|500 mg of proteose peptone-yeast extract per liter. For two cultures| growth in 0.1| 1.0| and 1|000 mg of proline per liter was also examined. At 10 to 15-degrees-C and above| growth rates showed no marked effect of substrate concentration| while at -1.5 and 0-degrees-C| there was an increasing requirement for organic nutrients| with generation times in low-nutrient media that were two to three times longer than in high-nutrient media. Biovolume showed a clear dependence on substrate concentration and quality; the largest cells were in the highest-nutrient media. Biovolume was also affected by temperature; the largest cells were found at the lowest temperatures. These data have implications for both food web structure and carbon flow in cold waters and for the effects of global climate change| since the change in growth rate is most dramatic at the lowest temperatures.
3765,1992,3,4,BIOMASS ENERGY| FORESTS AND GLOBAL WARMING,Biomass in all its form currently provides about 14% of the world's energy| equivalent to 25 million bbl oil/day; in developing countries where it is the major energy source| biomass supplies 35% of total energy use. Although biomass energy use affects the flux of carbon to the atmosphere| the main carbon emission problem is caused by fossil fuels and land clearance for agriculture. Biomass fuels make no net contribution to atmospheric CO2 if used sustainably. A major global revegetation and reforestation effort is a possible strategy to reduce CO2 emissions and to slow the pace of climatic change. However| a more attractive alternative strategy might be to substitute fossil fuels| especially coal| with biomass grown specifically for this purpose producing modern fuels such as electricity| liquids and gases. This paper examines biomass energy use| devegetation| biomass burning| the implications for global warming and the ability of biomass to sequester CO2 and substitute for fossil fuels. It also discusses some socioeconomic and political issues. 2215,1992,3,4,CALIFORNIA CLEAN-AIR INITIATIVES - THE ROLE OF FUEL-CELLS,The interaction between energy and the environment has been recognized for some time| but increasing focus is being placed on the feedback mechanisms between the two as local/regional and federal governments address the issue of regional pollution and global climate change| respectively. In Los Angeles the continued severity of the air pollution problem has stimulated renewed efforts to significantly curtail emissions to meet the health-related air quality standards. This paper provides an overview of the ambient air quality in Los Angeles| the impact of previous emissions control strategies| and the additional reduction in emissions required to meet the health-related air quality standards (Air Quality Management Plan| 1991) The paper focuses upon the role of clean technologies such as the fuel cell to effect the emissions reductions required. Finally| there is a discussion of the demonstration programs| planned or underway| with fuel cells and related technologies in the South Coast Air Quality Management District (SCAQMD)| followed by some comments on the regulatory and legislative actions underway to stimulate new technologies.
2201,1992,2,4,CARBON STORAGE IN UPLAND FORESTS OF THE LAKE STATES,Carbon storage and dynamics are receiving increasing attention because of the hypothesized role of CO2 in global climate change. This study was carried out to determine total C storage in Lake States' forests| including C in biomass| forest floor| and mineral soil. Over-story trees were measured and samples of both forest floor and mineral soil (to 1 m) were collected from plots in 169 forest stands across Minnesota| Wisconsin| and Michigan. Five forest types were represented: balsam fir| Abies balsamea (L.) Mill.; jack pine| Pinus banksiana Lamb.; red pine| P. resinosa Ait.; aspen| Populus tremuloides Michx.; and northern hardwoods dominated by sugar maple| Acer saccharum Marsh. There were no strong geographic trends in C storage in biomass| forest floor| or mineral soil across the study area. Storage differed significantly among forest types. Each major C pool was related to a different set of descriptors. Total C storage| the sum of all pools| was related to forest type| stand age| available water| actual evapotranspiration| and soil day content| explaining about 65% of the variation. Use of soil and site descriptors did not completely account for the strong effects of forest type on C storage. Differences in the size of C pools| as related to time since disturbance and forest type| indicate that C storage in forests of the Lake States can be influenced by forest management activities. Patterns of C storage in these moist temperate ecosystems are not as strongly influenced by climatic variables as is C storage in grasslands to the west.
3785,1992,3,2,CARBON TAX AS A DYNAMIC OPTIMIZATION PROBLEM,Wasting the atmosphere globally with carbon dioxide and other greenhouse gases is a special case of environmental pollution. Emissions from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases| carbon dioxide| methane| CFC's and nitrous oxide. NO(x) and hydrocarbons contribute indirectly to the greenhouse effect by forming Ozone in the atmosphere. These increased concentrations will result in an increased global warming| and as a consequence in a rise of the atmospheric temperature and the ocean level and to other potentially serious climate changes. An approach to define the ''carbon tax'' as an aggregate environmental ''price'' is discussed based upon the concept of global warming potential. The paper formulates the model to estimate die CO2 tax as function Of CO2 emission reduction and combines preliminary estimates of the reduction potentials and costs of the CFCs| N2O| CH4 and NO(x)| to define the overall effect of CO2- equivalent emission reduction in Switzerland. Some conclusions on the international rationale are also discussed concerning the recommendations of the Toronto and IPCC Conferences and their applicability to Switzerland. 3731,1992,2,4,CHANGES IN LOCATION OF NATURAL ZONES AS A RESULT OF GLOBAL WARMING,Changes in distribution of natural zones connected with climatic changes in Russian territory are examined. Changes of areas of natural zones as a result of warming by 1.4-2.2-degrees-C are cited. These are illustrated by distribution maps comparing natural zones in Russian territory| at present and after warming by 1.4-2.2-degrees-C. 3736,1992,2,3,CHLOROFLUOROCARBONS IN THE ATMOSPHERE - TRENDS AND VERTICAL PROFILES,Chlorofluorocarbons with extremely long atmospheric lifetimes are responsible for both stratospheric ozone depletion and global warming as they accumulate in the atmosphere. Their average atmospheric concentrations in the northern/southern hemisphere have been monitored since 1979 in order to study their behaviors and the future trends of their concentrations in the atmosphere: 1. An extremely clean analytical system has been developed for accurate analysis of atmospheric chlorofluorocarbons| carbon tetrachloride| methyl chloroform and other halocarbons. Atmospheric samples were collected at the surface level by grab-sampling and analyzed by ECD gas chromatography. 2. The background atmospheric concentrations of CCl3F (CFC-11) and CCl2F2 (CFC-12) in the mid-latitude northern hemisphere have been increasing by 4% a year over the past decade. The concentrations of CFC-11 and CFC-12 observed in Antarctica have been 8-10% lower than those observed in the northern hemisphere in accordance with the predominant emission of chlorofluorocarbons in the northern hemisphere and the delay (-2 years) in their diffusion into the southern hemisphere across the Intertropical Convergence Zone. The CCl2FCClF2 (CFC-113) concentration in the atmosphere tends to increase much faster than those of CFC-11 and CFC-12. 3. The vertical profiles of chlorofluorocarbons in the stratosphere have also been measured by means of balloon grab-sampling and cryogenic sampling. They reflect how efficiently these compounds undergo UV-photolysis to release chlorine atoms and end up with depletion of the ozone layer in the stratosphere. 2180,1992,3,4,CHP DEVELOPMENT - IMPACTS OF ENERGY MARKETS AND GOVERNMENT POLICIES,Combined heat and power production (CHP) and district heating (DH) helped achieve the energy policy objectives in the OECD. The high production conversion efficiency of CHP and DH considerably improved energy security. Favourable economic conditions combined with supporting government policies fostered their development. This paper analyses the historical developments of DH systems and CHP production by public utilities and private industry. Examples from various OECD countries illustrate the different conditions which have fostered progress| particularly during the 1970s and early 1980s. But since the mid-1980s economic conditions have changed and increased uncertainties about the economic viability of CHP and DH have emerged. In recent years| however| new initiatives have started to develop. A survey of current activities in OECD member countries shows that this renewed interest is primarily the result of environmental concerns related to energy production and use and| in particular| to the danger of global climate change. These issues are likely to be pivotal parameters for the further development of CHP and DH.
2211,1992,2,4,CLASSIFYING PLANTS INTO GROUPS ON THE BASIS OF ASSOCIATIONS OF INDIVIDUAL TRAITS EVIDENCE FROM AUSTRALIAN SEMIARID WOODLANDS,1. A multivariate analysis of 43 traits of 300 species from semi-arid woodlands in western New South Wales. Australia is described. The 43 traits encompass vegetative| life-history| phenological and seed-biology characters. 2. Five main groups of species were produced which corresponded largely to growth form. These groups were (i) perennial forbs and C3 grasses| (ii) subshrubs of the family Chenopodiaceae| (iii) perennial C4 grasses| (iv) trees and shrubs and (v) annual forbs and grasses. The traits associated with these groups were vegetative| life-history and phenological. Seed-biology traits were poorly associated with the groups. 3. There were higher percentages of associations within and between vegetative| life-history and phenological traits| than within seed-biology traits. This has important consequences for models of vegetation dynamics in the context of species migrations under global climate change| as these models group species largely on the basis of their vegetative and life-history attributes.
3688,1992,2,3,CLIMATE CHANGE IN THAILAND AND ITS POTENTIAL IMPACT ON RICE YIELD,In Thailand| the world's largest rice exporter| rice constitutes a major export on which the economy of the whole country depends. Climate change could affect rice growth and development and thus jeopardize Thailand's wealth. Current climatic conditions in Thailand are compared to predictions from four general circulation models (GCMs). Temperature predictions correlate well with the observed values. Predictions of monthly rainfall correlate poorly. Virtually all models agree that significant increases in temperature (from 1 to 7-degrees-C) will occur in the region including Thailand following a doubling in atmospheric carbon dioxide (CO2) concentration. The regional seasonality and extent of the rise in temperature varies with each model. Predictions of changes in rainfall vary widely between models. Global warming should in principle allow a northward expansion of rice-growing areas and a lengthening of the growing season now constrained by low temperatures. The expected increase in water-use efficiency due to enhanced CO2 might decrease the water deficit vulnerability of dryland rice areas and could make it possible to slightly expand them. 3676,1992,3,3,CLIMATE CHANGE MANAGEMENT STRATEGIES - LESSONS FROM A THEORY OF LARGE-SCALE POLICY,Climate change management strategies| which are intended to stabilize| slow or prevent global warming through global reductions in the production or presence of greenhouse gases| are currently under discussion in the context of a Framework Convention on Climate Change. This article addresses the concept of 'scale' and its relevance to the design and implementation of policy. Paul R. Schulman's 'theory of large-scale policy' is used to illuminate both prospects and problems of implementing climate change management strategies. This approach helps to highlight practical reasons why it will be a challenge to build or sustain international support for efforts to prevent or slow climate change. 2209,1992,4,2,CLIMATE FORCING BY ANTHROPOGENIC AEROSOLS,Although long considered to be of marginal importance to global climate change| tropospheric aerosol contributes substantially to radiative forcing| and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo| thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be - 1 to - 2 watts per square meter| globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus| the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However| differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past| current| and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.
3726,1992,3,3,CO2 SEPARATION AND RECYCLING - A ROUTE TO ZERO NET PRODUCTION OF CO2 IN THE ALBERTA ENERGY INDUSTRY,CO2 is known to be a key contributor to the green house effect resulting in global warming. Since energy industry is the major producer Of CO2 it shares the responsibility of reducing the impact Of CO2 emissions from various energy related activities. CO2 is generated by the energy industry in a number of different ways. Some of it is simply recovered in its natural state| for example production of CO2 with CO2 containing natural gases while some other are generated in the chemical conversion processes of upgrading| processing and manufacturing of chemicals| for example generation of CO2 as a by product in the manufacturing of hydrogen and syn-gas. While some activities in the energy sector results in the production of CO2| other activities also require consumption of CO2. Most important CO2 consuming operation is the injection Of CO2 for the enhanced recovery of oils| which would otherwise be left unrecovered. This paper examines reduction in CO2 emissions in the energy production and processing activities in Alberta| by recovering all the CO2 produced and recycling the produced CO2 into the reservoir for enhanced oil recovery projects. The status Of CO2 recovery processes is critically reviewed and feasibility Of CO2 supply network connecting the production and utilisation sites in the context of the Province of Alberta is discussed. The CO2 supply network envisaged| may consist of pipelines| skid mount CO2 liquefaction plants and CO2 transport vehicles as well as CO2 injection compressors and wells. It is argued that zero net production of CO2 is possible under the proposed recycling options. 2212,1992,2,4,CO2LT AN AUTOMATED| NULL-BALANCE SYSTEM FOR STUDYING THE EFFECTS OF ELEVATED CO2 AND GLOBAL CLIMATE CHANGE ON UNMANAGED ECOSYSTEMS,An automated| CO2-controlled| long-term greenhouse system ('CO2LT') has been developed to provide replicated in situ ecosystem-level manipulation of atmospheric CO2 concentration and temperature for intact plots of tussock tundra| and to measure the instantaneous ecosystem-level CO2 exchange rates within each of the plots under the treatments imposed. This is a computer-controlled| closed| null-balance greenhouse system consisting of 12 chambers with individual control of CO2 concentration and temperature. Carbon dioxide can be maintained in each chamber at concentrations from well below ambient (150-200-mu-l l-1) to more than 900-mu-l l-1. Air temperature can be fixed| set to track ambient| or can track ambient temperature with a specified offset allowing studies of the interaction of CO2 and temperature. Despite the complications involved in tracking a naturally fluctuating environment| the CO2LT system performs very well. Temperatures in individual chambers average within 1-degrees-C of ambient or target temperatures over a 24-h period and carbon dioxide concentration control rivals that of laboratory-based| control-environment systems. Photon flux density within the chambers is within 93% of ambient values. Comparison to unenclosed tundra indicates minimal chamber effects on depth of thaw| air| leaf| or soil temperatures| or net ecosystem CO2 flux. Chamber effects are generally small| and the experimental design allows separation and interpretation of treatment effects despite any unavoidable chamber effects. Both diurnal and seasonal patterns of net ecosystem CO2 flux can be accurately tracked with this system. Field measurements indicate net ecosystem CO2 loss under current environmental conditions| a possible response to recent climate change. Field measurements also indicate initial enhancement of net ecosystem CO2 uptake with elevated atmospheric CO2. Photosynthetic adjustment to elevated CO2 lowers ecosystem response to that of ambient chambers by mid-season. Also indicated is the possibility of delayed senescence of photosynthetic capacity at elevated CO2.
3737,1992,3,3,COASTAL DEFENSE - THE RETREAT OPTION,In a recent report| the Intergovernmental Panel on Climate Change predicted an average rise in global sea levels due to global warming of 180 mm by the year 2030| and 440 mm by 2070. These increases could potentially compound a problem which is already appearing on the UK flood-defence agenda with increasing frequency| i.e. whether the country should continue to defend areas of agricultural land which currently have little or no national economic value. This paper explores the opportunities for nature conservation which might arise if 'retreat' from the existing line of defence is accepted as an option. The current situation in the UK and the United States is reviewed| and some possible responses are discussed. 2203,1992,4,4,CUMULUS CLOUD-BASE HEIGHT ESTIMATION FROM HIGH SPATIAL-RESOLUTION LANDSAT DATA - A HOUGH TRANSFORM APPROACH,Cloud base height is an essential variable governing surface energy budgets| but it is notoriously difficult to determine using satellite data. This study develops a semiautomated methodology to estimate cumulus cloud base heights using high spatial resolution LANDSAT Multispectral Scanner data. The approach employs a variety of image processing techniques to match cloud edges with their corresponding shadow edges. Cloud base height then is estimated by computing the separation distance between the corresponding Generalized Hough Transform reference points. Sixteen subregions| each 30 km x 30 km in size| are selected for four LANDSAT scenes. Standard deviations of cloud base height within each of the subregions range from about 100 m to 150 m. Differences between cloud base heights computed using the Hough Transform and a manual verification technique are small (on the order of 100 m or less). The cloud base heights also compare favorably with the few surface observations available. On the basis of these results| it is estimated that cloud base height accuracies of 50-70 m may be possible using HIRIS and ASTER instruments in the EOS Global Climate Change program.
3632,1992,5,2,DERIVING GLOBAL CLIMATE SENSITIVITY FROM PALEOCLIMATE RECONSTRUCTIONS,To assess the future impact of anthropogenic greenhouse gases on global climate| we need a reliable estimate of the sensitivity of the Earth's climate to changes in radiative forcing. Climate sensitivity is conventionally defined as the equilibrium surface temperature increase for carbon dioxide doubling| DELTAT2x. Uncertainties in cloud processes spread general circulation model (GCM) estimates of this parameter over the range 1.5 < DELTAT2x < 4.5-degrees-C (refs 1| 2). An alternative to model-based estimates is in principle available from the reconstruction of past climates3-6| which implicitly includes cloud feedback. Here we retrieve the sensitivity of two palaeoclimates| one colder and one warmer than present| by independently reconstructing both the equilibrium surface temperature change and the radiative forcing. Our results yield DELTAT2x = 2.3 +/- 0.9-degrees-C. This range is comparable with estimates from GCMs and inferences from recent temperature observations and ocean models7|8. Future application of the method to additional climates in the geological record might constrain climate sensitivity enough to narrow the model uncertainties of global warming predictions. 2168,1992,2,4,DISPERSAL CAN LIMIT LOCAL PLANT-DISTRIBUTION,The ability of species to establish new populations at unoccupied sites is a critical feature in the maintenance of biological diversity| and it bas taken on new importance as a result of global climate change and expected changes in species distribution. To examine the dispersal potential of plant species| seeds of four annual plant species were experimentally dispersed 40 to 600 m from existing populations in Massachusetts (U.S.A) to 34 nearby unoccupied but apparently suitable sites. At three of these sites| new populations were established that persisted for four generations and expanded slowly in area At seven sites a small initial population eventually died out At the 24 other sites| new populations did not become established| indicating that the sites were in some way unsuitable| that not enough seeds arrived| or that conditions suitable for seed germination do not occur every year. These results suggest that some species may be unable to disperse naturally out of their existing ranges in response to global climate change| particularly if habitat fragmentation creates barriers to dispersal. These species may have to be assisted to reach suitable sites nearby to prevent their extinction in the wild.
3680,1992,4,3,ECOLOGICAL ENGINEERING - AN IDEA WHOSE TIME HAS COME,The era of cheap fossil fuels is nearing its end. Industrial| agricultural and human pollutants have reached alarming levels in water| soil| air and stratosphere. Consumers no longer tolerate poisons in their food and water| are now concerned with global warming and ozone depletion| and value fields and forests for their scenery and wildlife as well as food and fibre. We are at the crossroads| searching for answers to these and many other pressing ecological problems. On one side sit 'deep ecologists' who patiently await the reactions of global Gaia. On the other sit 'biotechnologists' who would design and build new organisms and new ecosystems. The first approach is defeatist| for it awaits the decimation of the human population. The other is activist| but will it work? Here we examine the idea of 'ecological engineering'| which offers some promise of solutions to our problems if it can integrate the practical sides of ecosystem| landscape| community and population ecology with relevant formal concepts from the engineering sciences. 2202,1992,2,4,ECOLOGICAL IMPLICATIONS OF PROJECTED CLIMATE CHANGE SCENARIOS IN FOREST ECOSYSTEMS IN NORTHERN MICHIGAN| USA,Changes in seasonal temperature and precipitation| as predicted by several global climate models| were utilized together with a stochastic daily weather stimulation model to evaluate the ecological impacts of projected global climate change scenarios on temperate forest ecosystems on northern Michigan| USA. The model simulated the impacts of these projected changes on ecologically significant weather variables| such as the length of the frost-free period| average growing season temperature| average growing season degree days (4.4-degrees-C basis)| summer precipitation| potential evaporation during| the growing season| and the ratio of precipitation to potential evaporation during July and August. The results indicate that even the lower range of predicted climate changes could lead to ecologically and commercially significant changes in the composition and productivity of these forests. Of particular concern is the possibility of climatically induced regional decline episodes for a number of important commercial species in the northern temperate forests of central North America.
2189,1992,2,4,ECONOMIC-IMPLICATIONS OF GLOBAL CLIMATE CHANGE FOR WORLD AGRICULTURE,This paper challenges the hypothesis that negative yield effects in key temperate grain producing regions of the world resulting from global climate change would have a serious impact on world food production. Model results demonstrate that even with concurrent productivity losses in the major grain producing regions of the world| global warming will not seriously disrupt world agricultural markets. Country/regional crop yield changes induce interregional adjustments in production and consumption that serve to buffer the severity of climate change impacts on world agriculture and result in relatively modest impacts on world agricultural prices and domestic economies.
2182,1992,3,4,ECONOMIC-ISSUES IN GLOBAL CLIMATE CHANGE,The author highlights the critical role of economics in understanding the potential magnitude of global climate change as a problem for human society and for assessing and developing effective responses. It is shown that many of the basic economic tools and techniques needed to address global climate change issues are already found in the existing environmental and natural resource economics literature. However| in the application of economic concepts to climate change problems| much work remains. It is suggested that priority areas for future economic research include analysis of the impacts and the adaptation of economic systems| the value of information and decision making under uncertainty| and the development of world models of the economy that aid in understanding and predicting the sources and effects of global change that are linked to economic activity.
3639,1992,2,2,ECONOMICS AND THE GREENHOUSE-EFFECT,There is growing scientific and public concern that increasing concentrations of greenhouse gases in the atmosphere will produce global warming and other climatic changes. Although economic activity is the main source of greenhouse gas emissions| information and incentive problems make it difficult to translate concern about global warming into economic behaviour and policy conducive to reducing emissions. The paper considers a set of near term (carbon tax)| intermediate term (afforestation| energy efficiency) and long term (new non-fossil fuel technologies) strategies for reducing CO2 in the atmosphere. Each strategy has useful attributes| but shortcomings or limitations too. While the near term and intermediate term strategies can slow and perhaps reverse the growth of CO2 emissions| only a successful long term strategy of fostering the development of some promising non-fossil fuel technologies| such as solar and solar-hydrogen| can eventually halt the build-up of CO2 in the atmosphere. Moreover| public investment in the development of new non-fossil fuel technologies would largely obviate the information and incentive problems that currently stand in the way of an economically viable greenhouse policy. 3693,1992,2,4,ECOSYSTEM-LEVEL CHANGES THAT MAY BE EXPECTED IN A CHANGING GLOBAL CLIMATE - A BRITISH-COLUMBIA PERSPECTIVE,British Columbia is a vast province encompassing a wide latitudinal and elevational range. Four of the five major classes of climate in the world are found in British Columbia| where prevailing westerly winds from the Pacific and a series of north-south mountain ranges have produced widely differing local climates. The predicted global warming may result in the migration of species and communities upslope and toward the north| but the heterogenous nature of the present landscape suggests that such migration may not be as pronounced as that likely to occur in regions of Canada with less relief. Effects of climatic warming on long-lived temperate zone trees include possible increased frost damage in early spring; reduced seed production; increased insect and disease incidence; increased damage to forests by wildfire; and| in the warmer parts of coastal British Columbia| a winter climate too warm to satisfy the chilling requirements of some perennial plants. 3652,1992,2,4,EFFECT OF GLOBAL WARMING ON THE DISTRIBUTION OF PARASITIC AND OTHER INFECTIOUS-DISEASES - A REVIEW,Assuming current trends continue| significant global warming via the 'greenhouse effect' seems-ineVitable; disequilibrium in physical and biological ecosystems will ensue| and the faster the changes occur the less likely it is that human (and other) societies will be able to adapt without serious resultant consequencesl14. Natural climatic changes in the past have occurred over| thousands or millions of years; global warming of 5000 to 15 000 years ago completely changed the face of the planet 6; this was| howevr| insidious unlike the rapid change which man-made 'global-warming' will precipitate. Present predictions on extent and geographical distribution of climatic change are based on incomplete scientific projections coupled with a significant quota of crystal-ball gazing! The potential impact of climatic change on communicable disease patterns can be summarized3: (i) modification of vector (usually arthropod) ecology - this relates principally to infections curently prevalent in tropical and subtropical regions| (ii) intensification of human-related risk factors - including reduced availability and quality of drinking water| cooking and sanitation facilities| extent of irrigation| etc| and (iii) an increase in soil| airborne and other diseases| directly related to the socioeconomic consequences of changed human behaviour.
3659,1992,2,4,EFFECTS OF BOREAL FOREST VEGETATION ON GLOBAL CLIMATE,TERRESTRIAL ecosystems are thought to play an important role in determining regional and global climate1-6; one example of this is in Amazonia| where destruction of the tropical rainforest leads to warmer and drier conditions4-6. Boreal forest ecosystems may also affect climate. As temperatures rise| the amount of continental and oceanic snow and ice is reduced| so the land and ocean surfaces absorb greater amounts of solar radiation| reinforcing the warming in a 'snow/ice/albedo' feedback which results in large climate sensitivity to radiative forcings7-9. This sensitivity is moderated| however| by the presence of trees in northern latitudes| which mask the high reflectance of snow10|11| leading to warmer winter temperatures than if trees were not present12-14. Here we present results from a global climate model which show that the boreal forest warms both winter and summer air temperatures| relative to simulations in which the forest is replaced with bare ground or tundra vegetation. Our results suggest that future redistributions of boreal forest and tundra vegetation (due| for example| to extensive logging| or the influence of global warming) could initiate important climate feedbacks| which could also extend to lower latitudes. 3687,1992,2,3,EFFECTS OF CLIMATE CHANGE AND A DOUBLING OF CO2 ON VEGETATION DIVERSITY,A model is presented for predicting the response of global family diversity to global environmental change. The model assumes that three primary mechanisms determine diversity: the capacity to survive the absolute minimum temperature of a site| the ability to complete the life cycle in a given length and warmth of the growing season| and the capacity to expand leaves in a defined regime of precipitation and vegetation transpiration. The direct effects of CO2 on vegetation transpiration are also included. About one-third of the floristic regions of the world exhibit increased diversity with a 3-degrees-C increase in temperature| a 10% increase in precipitation| and a doubling of the CO2 concentration. The addition of CO2 offsets the increased rates of transpiration| caused by global warming through its capacity to reduce transpiration. As a consequence| the diversity of dry regions displayed the greatest increase in diversity due to increased CO2. 3650,1992,2,4,EGGS| ENZYMES| AND EVOLUTION - NATURAL GENETIC-VARIANTS CHANGE INSECT FECUNDITY,Phosphoglucose isomerase genotypes in the butterfly Colias differ dramatically in biochemical properties. These differences were evaluated earlier| using metabolic network theory| to predict| successfully| their effects on glycolytic metabolism and hence on Colias flight capacity and several consequent fitness components in the wild. Female egg-laying| not previously studied| also depends on flight| so female fecundity is now predicted to differ among these genotypes. An experimental design incorporating the thermal ecology of Colias confirms these predictions in a cool habitat. Thus female fecundity differences among animal enzyme polymorphs have now been found. Quantitative reconstruction of the selection regime for phosphoglucose isomerase genotypes in Colias can now begin. The most heat-stable genotypes are the least fecund| suggesting that global warming| if it occurs| may have severe impacts| through population genetics| on demography of thermally sensitive creatures. 3743,1992,3,4,ENERGY DEVELOPMENT| REGIONAL COOPERATION| AND CO2 EMISSIONS IN CENTRAL-AMERICA,For the countries of Central America| international cooperation in the area of global warming has sharpened the economic growth v environmental protection tradeoff. This paper simulates two energy futures for Central America as a region: a minimum cost (maximum development) scenario and a minimum CO2 emissions scenario. The tradeoffs between these two scenarios identify a frontier demonstrating the costs of cutting carbon emissions in Central America. As these costs are relatively low| Central America can use them to negotiate treaties| agreements| and eventually the sale of carbon emission rights to countries or companies facing more expensive carbon reduction strategies. 3642,1992,3,3,ENERGY PAYBACKS AND RENEWABLE BREEDERS,The feasibility of using renewable energy technologies to displace fossil fuels and mitigate global warming depends on the possibility of developing solar breeders. A solar breeder can be either a conceptual tool for analyzing any energy source or a physical plant to demonstrate the viability of renewable energy. The mathematics of breeders is discussed| and problems with previously used equations are demonstrated. The status of currently available renewable energy technologies is reviewed| and the importance of better information and of physical-breeder demonstrations is discussed. 2193,1992,4,4,ENERGY| EFFICIENCY| AND THE ENVIRONMENT - 3 BIG ES OF TRANSPORTATION,The three big Es of transportation are Energy| Efficiency| and the Environment. As the clouds of global climate change and the desire to rely less on Mid-East crude builds| how do manufacturers and refiners reconcile the needs of consumer acceptance and governmental regulation? How can policies and practices be united so that everyone involved works to the common goal of personal mobility? This lecture traces recent events that have resulted in paradox on top of paradox. As industry continues to react to the latest round of air pollution regulations| where are we headed as far as new CAFE limits and the potential for additional longer term controls related to the greenhouse effect? These are issues that will affect those in the equipment and oil industry| as well as the consumer| in the days ahead.
3771,1992,3,4,ENVIRONMENTAL AUDITING - ESTIMATING AND REDUCING CORPORATE GREENHOUSE-GAS EMISSIONS USING MONITORING AND TARGETING SOFTWARE SYSTEMS,Current concerns about global warming| the alleged increasing greenhouse effect| environmental instability and sustainable developments have prompted organisations to devise and implement environment audits. These are undertaken in order to assess the impact an organisation's activities have on the environment and should include obtaining estimates for the airborne pollution and greenhouse-gas emissions produced. Recommendations are normally made to lessen detrimental effects on the environment and these aims are increasingly incorporated in organisations environment policies. Reducing greenhouse-gas emissions and improving corporate profitability can be mutually compatible. Estimating emissions from multi-site organisations (as part of a corporate environmental audit) can be a difficult and lengthy task. The present paper describes a computer model| which has been developed to estimate corporate greenhouse-gas and airborne-pollutant emissions from readily-available fuel-invoice information and/or plant details. How monitoring and targeting techniques| developed for energy-thrift campaigns| can be used to monitor and reduce corporate greenhouse-gas emissions| with little or no capital outlay| by reducing energy waste| are also described. 2220,1992,3,2,ETHICAL ISSUES CONCERNING POTENTIAL GLOBAL CLIMATE CHANGE ON FOOD-PRODUCTION,Burning fossil fuel in the North American continent contributes more to the CO2 global warming problem than in any other continent. The resulting climate changes are expected to alter food production. The overall changes in temperature| moisture| carbon dioxide| insect pests| plant pathogens| and weeds associated with global warming are projected to reduce food production in North America. However| in Africa| the projected slight rise in rainfall is encouraging| especially since Africa| already suffers from severe shortages of rainfall. For all regions| a reduction in fossil fuel burning is vital. Adoption of sound ecological resource management| especially soil and water conservation and the prevention of deforestation| is important. Together| these steps will benefit agriculture| the environment| farmers| and society as a whole.
2186,1992,4,4,FIELD-MEASUREMENTS OF CO2 ENHANCEMENT AND CLIMATE CHANGE IN NATURAL VEGETATION,It is generally assumed that healthy| natural ecosystems have the potential to sequester carbon under favorable environmental conditions. There is also evidence that CO2 acts as a plant fertilizer. It is of interest to know if these assumptions are valid and how natural systems might respond under future scenarios of CO2 increase and possible climate changes. Few measurements of the effects of CO2 and global climate change have been made on "natural" ecosystems under realistic field conditions. Most measurements have been conducted in the synthetic environments of totally controlled greenhouses and growth chambers. Several lines of evidence indicate that controlled environment studies using plants growing in pots induce experimental artifacts that reduce confidence in the use of results for prediction of future global responses. Open top chambers are being used in several autecological field studies in an attempt to obtain more realistic field environments. A few field microcosm studies have been completed and a system for the free air release of CO2 has been applied in cotton fields. Unfortunately| the requirement of large amounts of CO2 and financial restrictions have precluded the initiation of larger scale field studies in natural vegetation. This paper lists and summarizes the best field studies available but draws heavily on studies from artificial environments and conditions in an attempt to summarize knowledge of global environmental change on forests and other non-agricultural ecosystems. Finally the paper concludes that there is a need for the development and application of equipment for field measurements in several representative natural ecosystems and makes specific recommendation of the creation of a tropical research center.
3764,1992,4,4,FOREST RESPONSE TO CLIMATIC-CHANGE - EFFECTS OF PARAMETER-ESTIMATION AND CHOICE OF WEATHER PATTERNS ON THE RELIABILITY OF PROJECTIONS,Computer projections suggest that forests may respond dramatically and rapidly to global warming| with significant and readily observable changes in forests of mid-latitudes occurring by the turn of the century or shortly thereafter. These results raise the question: how reliable are the projections? Sensitivity analyses reported in this paper suggest that projections of forest response to global warming will be generally insensitive to errors of 10% in parameter estimation. Even where projections are sensitive quantitatively| they are not change in timing. Projections are insensitive to the choice of baseline weather records| unless the warmest or coldest decades of the 20th century are used as baselines. 3682,1992,3,3,FORESTRY OPPORTUNITIES IN THE UNITED-STATES TO MITIGATE THE EFFECTS OF GLOBAL WARMING,There are a variety of opportunities in the United States to expand the area of trees and forests| and to improve their growth| that could have significant impact upon the annual uptake of atmospheric CO2. Work coordinated by the American Forestry Association has attempted to quantify those opportunities| and demonstrate what kinds of costs and benefits might result from an attempt to begin implementing them. The first section of the work| reported in this paper| has focused on the opportunities that are seldom thought of as regular forestry-planting trees on marginal crop and pasture lands| increasing windbreaks and shelterbelts| growing trees as a biomass energy source| and improving urban tree canopies and placements as an energy-conserving measure. The benefits from such work include thc C sequestered in the biomass and soils involved| as well as the carbon emission reductions achieved through energy conservation. These opportunities could add up to a total C impact per year in the range of 141 to 382 x 10(6)t-somewhere between 10 and 30% of the current net C emission from fossil fuel in the United States. Additional work is underway to quantity the opportunities inherent in improving the management of existing forestlands| through more traditional forestry. The results of that work will be available in late 1992. 2188,1992,2,4,GENETIC STRATEGIES FOR REFORESTATION IN THE FACE OF GLOBAL CLIMATE CHANGE,If global warming materializes as projected| natural or artificial regeneration of forests with local seed sources will become increasingly difficult. However| global warming is far from a certainty and predictions of its magnitude and timing vary at least twofold. In the face of such uncertainty| reforestation strategies should emphasize conservation| diversification| and broader deployment of species| seed sources| and families. Planting programs may have to deploy non-local seed sources| imported from further south or from lower elevations| which necessitates a system for conserving native gene pools in seed banks or clone banks. Planting a diverse array of species or seed sources is a hedge against the uncertainty inherent in current projections of warming. Most tree improvement programs already stress genetic diversity and deployment of multi-progeny mixes| but may better prepare for climate change by testing selections in an even wider set of environments than is now the case.
2171,1992,4,4,GENOTYPE-ASTERISK ENVIRONMENT INTERACTION - A CASE-STUDY FOR DOUGLAS-FIR IN WESTERN OREGON,Unrecognized genotype x environment interactions (g*e) can bias genetic-gain predictions and models for predicting growth dynamics or species perturbations by global climate change. This study tested six sets of families in 10 plantation sites in a 78-thousand-hectare breeding zone. Plantation differences accounted for 71 percent of sums of squares (15-year heights)| replications an additional 4.4 percent| families 1.9 percent| the first principal component of interaction effects 3.5 percent| and the second principal component 1.2 percent. Results in this study and in a larger survey (87 sets in 10 breeding zones) were similar: 51 percent of sets indicated significant g*e. In 46 percent of sets| the g*e interaction-family variance ratio was greater than 1; in 35 percent| greater than 1.5; and in 10 percent| greater than 5.
3634,1992,2,3,GEOTHERMAL CONDITIONS FOR GAS HYDRATE STABILITY IN THE BEAUFORT-MACKENZIE AREA - THE GLOBAL CHANGE ASPECT,Gases locked in hydrates or trapped beneath a gas hydrate cap within the earth are potential contributors to the greenhouse effect| and therefore both thermal conditions of and occurrences of the methane hydrates should be considered in the study of past climate change and of future global warming. The decomposition of methane hydrates triggered by an increase in near surface temperatures and the subsequent upward migration of released gases is occurring at present in the Beaufort-Mackenzie area of northern Canada. In addition to surface warming| the warming effect of the upward flow of the deep fluids| recharged in high elevation areas bordering the Alaska and Yukon coastal plain| may also be a factor in the release of methane directly from deeper buried hydrates in the fluid discharge zones. Any assessment of the total methane contribution to the atmosphere and the rate of the release requires a knowledge of the distribution| spatially and with depth| the temperature and composition of the gas hydrates. In this study the zones of methane hydrate stability are predicted by a thermal method and compared with the distribution of hydrates detected on well logs. An extensive hydrate prone layer extending to as deep as 1400 +/- 200 m over an area of 50|000 km2 is predicted by the thermal data and hydrate stability field. Comparison of the predicted maximum depths of methane hydrate stability with the maximum depths of hydrate occurrences in 52 wells shows general agreement in the areas of thick offshore and onshore permafrost. Differences in several areas of up to 400 m between the thermally predicted hydrate base and the deepest detected hydrates (detected hydrates are deeper than the predicted ones) can be explained by changes in gas composition. Otherwise low near-surface thermal gradients of approximately 15 mK/m to 20 mK/m (in comparison with observed deep thermal gradients of 25-40 mK/m) would be needed to explain the existence of deep hydrates in the area of the southern Mackenzie Delta trough and offshore north of 71-degrees-N latitude. Unfortunately there is no reliable industrial temperature observation from wells to support the latter. Such regional studies of the distribution of gas hydrates| including the stability of those deposits| form a crucial component of an assessment of the influence of gas hydrate formation and decomposition on the proportion of methane present in the earth's atmosphere. Current estimates suggest that between 10.E18 and 10.E21 tonnes of methane may be presently locked in gas hydrate deposits. To fully assess the total amount and the potential contribution to global warming| similar regional assessments are needed for each of the major areas of occurrence| especially in the circumpolar regions which are subject to the greatest increase in temperature conditions. 3635,1992,2,4,Geothermal conditions for gas hydrate stability in the Beaufort-Mackenzie area: the global change aspect,Gases locked in hydrates or trapped beneath a gas hydrate cap within the earth are potential contributors to the greenhouse effect| and therefore both thermal conditions of and occurrences of the methane hydrates should be considered in the study of past climate change and of future global warming. The decomposition of methane hydrates triggered by an increase in near surface temperatures and the subsequent upward migration of released gases is occurring at present in the Beaufort-Mackenzie area of northern Canada. In addition to surface warming| the warming effect of the upward flow of the deep fluids| recharged in high elevation areas bordering the Alaska and Yukon coastal plain| may also be a factor in the release of methane directly from deeper buried hydrates in the fluid discharge zones. Any assessment of the total methane contribution to the atmosphere and the rate of the release requires a knowledge of the distribution| spatially and with depth| the temperature and composition of the gas hydrates. In this study the zones of methane hydrate stability are predicted by a thermal method and compared with the distribution of hydrates detected on well logs. An extensive hydrate prone layer extending to as deep as 1400 +/- 200 m over an area of 50|000 km 2 is predicted by the thermal data and hydrate stability field. Comparison of the predicted maximum depths of methane hydrate stability with the maximum depths of hydrate occurrences in 52 wells shows general agreement in the areas of thick offshore and onshore permafrost. Differences in several areas of up to 400 m between the thermally predicted hydrate base and the deepest detected hydrates (detected hydrates are deeper than the predicted ones) can be explained by changes in gas composition. Otherwise low near-surface thermal gradients of approximately 15 mK/m to 20 mK/m (in comparison with observed deep thermal gradients of 25-40 mK/m) would be needed to explain the existence of deep hydrates in the area of the southern Mackenzie Delta trough and offshore north of 71 degrees N latitude. Unfortunately there is no reliable industrial temperature observation from wells to support the latter. Such regional studies of the distribution of gas hydrates| including the stability of those deposits| form a crucial component of an assessment of the influence of gas hydrate formation and decomposition on the proportion of methane present in the earth's atmosphere. Current estimates suggest that between 10.E18 and 10.E21 tonnes of methane may be presently locked in gas hydrate deposits. To fully assess the total amount and the potential contribution to global warming| similar regional assessments are needed for each of the major areas of occurrence| especially in the circumpolar regions which are subject to the greatest increase in temperature conditions. 2176,1992,2,2,GLOBAL CLIMATE CHANGE,A succession of environmental events over the last few years has led to a dramatically increased awareness of the issue of global climate change and to the conviction that global climate change is occurring. The anticipated global climate changes are new and unique in that they will have been generated by human activity and could result in large-scale disruptions in ecosystems altering the suitability for organisms currently occupying them. The goals of both conservation biology and agriculture of feeding an increasing world population and preserving species diversity may be seriously challenged when linked to climate change. Anticipated atmospheric changes in precipitation patterns| temperature| and greenhouse gases could have extreme effects on species and ecosystems. Human systems could also bc affected| especially those based on coastal wetlands or shared river basins. Agriculture will be profoundly affected| with local| regional| and global changes occurring. Species distribution is likely to be drastically altered as a consequence of global warming.
2198,1992,2,2,GLOBAL CLIMATE CHANGE - ECOSYSTEMS EFFECTS,Much concern is felt about global warming and many debates have ranged widely on this subject without as yet arriving at a precise answer; the 'best guess' at present is a 60% chance of a global average change in the 1.5-4.5 K range if carbon dioxide concentrations were to double. However| regional temperature changes are still more speculative depending on the heat retaining properties of the oceans and the continents. The reaction of ecosystems to climatic change is here illustrated by considering forests and birds| and it is concluded that the more rapid the climatic change| the higher the probability of disruption and surprise in the ecosystems affected. The author finally recommends the banning of chlorofluorocarbons and switching fuels from coal to natural gas thus buying time and slowing down global warming.
3656,1992,2,3,GLOBAL CLIMATIC-CHANGE| HURRICANES| AND A TROPICAL FOREST,Most| if not all forests in the Caribbean are subject to occasional disturbances from hurricanes. If current general circulation model (GCM) predictions are correct| with doubled atmospheric CO2 (2 x CO2)| the tropical Atlantic will be between 1-degrees-C and 4-degrees-C warmer than it is today. With such a warming| more than twice as many hurricanes per year could be expected in the Caribbean| Furthermore| Emanuael (1987) indicates that in a warmed world the destructive potential of Atlantic hurricanes could be increased by 40% to 60%. While speculative| these increases would dramatically change the disturbance regimes affecting tropical forests in the region and might alter forest structure and composition. Global warming impacts through increased hurricane damage on Caribbean forests are presented. An individual tree| gap dynamics forest ecosystem model was used to simulate the range of possible hurricane disturbance regimes which could affect the Luquillo Experimental Forest in Puerto Rico. Model storm frequency ranged from no storms at all up to one storm per year; model storm intensity varied from no damage up to 100% mortality of trees. The model does not consider the effects of changing temperature and rainfall patterns on the forest. Simulation results indicate that with the different hurricane regimes a range of forest types are possible| ranging from mature forest with large trees| to an area in which forest trees are never allowed to reach maturity. 3677,1992,2,4,GLOBAL SEA-LEVEL ACCELERATION,Greenhouse warming scenarios commonly forecast an acceleration of sea level rise in the next 5 or 6+ decades in the range 0.1-0.2 mm/yr2. Long tide gauge records (75 years minimum) have been examined for past apparent sea level acceleration (i.e.| deviation from a purely linear rise) and for indication of how long it might take to detect or verify a predicted future acceleration. For the 80-year period 1905-1985| 23 essentially complete tide gauge records in 10 geographic groups are available for analysis. These yielded the apparent global acceleration -0.011 (+/-0.012) mm/yr2. A larger| less uniform set of 37 records in the same 10 groups with 92 years average length covering the 141 years from 1850 to 1991 gave for acceleration 0.001 (+/-0.008) mm/yr2. Thus there is no evidence for an apparent acceleration in the past 100+ years that is significant either statistically| or in comparison to values associated with global warming. Estimating how well a global acceleration parameter could be determined in a relatively short time was accomplished by dividing the 1905-1985 data set into four equal time spans. The formal 1-sigma uncertainty (about 0.2 mm/yr2) of global acceleration from these 20-year periods is more than an order of magnitude larger than for the 80- and 141-year cases owing to the existence of large interdecadal and longer variations of sea level. This means that tide gauges alone cannot serve as a leading indicator of climate change in less than at least several decades. Confirming the prediction of a particular model at the 95% confidence level or differentiating between model predictions will take much longer. The time required can be significantly reduced if the interdecadal fluctuations of sea level can be understood in terms of their forcing mechanisms and then removed from the tide gauge records. 3661,1992,4,5,GLOBAL WARMING - A REDUCED THREAT,One popular and apocalyptic vision of the world influenced by increasing concentrations of infrared-absorbing trace gases is that of ecological disaster brought about by rapidly rising temperatures| sea level| and evaporation rates. This vision developed from a suite of climate models that have since considerably changed in both their dynamics and their estimates of prospective warming. Observed temperatures indicate that much more warming should already have taken place than predicted by earlier models in the Northern Hemisphere| and that night| rather than day| readings in that hemisphere show a relative warming. A high-latitude polar-night warming or a general night warming could be either benign or beneficial. A large number of plant species show both increased growth and greater water-use efficiency under enhanced carbon dioxide. An extensive body of evidence now indicates that anthropogenerated sulfate emissions are mitigating some of the warming| and that increased cloudiness as a result of these emissions will further enhance night| rather than day| warming. The sulfate emissions| though| are not sufficient to explain all of the night warming. However| the sensitivity of climate to anthropogenerated aerosols| and the general lack of previously predicted warming| could drastically alter the debate on global warming in favor of less expensive policies.
3667,1992,4,3,GLOBAL WARMING - GREENHOUSE GASES VERSUS AEROSOLS,Man's activities have led to an increase in the atmospheric concentration of aerosols and the aerosol precursors as well as to an increase of greenhouse gases. A crude measure of man's global activities| which cause these increases| is the annual emission of carbon-in the form of CO2 from the burning of fossil fuels. Hence as a first approximation| the additional releases of greenhouse gases and the additional production of aerosols are assumed to be proportional to the annual carbon emissions. A simple OD-model provides an estimate of the responses of the global annual average surface temperature to the increase of greenhouse gases and of aerosols. The albedo increase is estimated under the assumption that the additional aerosol production leads to a proportional increase in available cloud condensation nuclei and that the increase of greenhouse gases leads to a proportional decrease in the infrared transmittance of the atmosphere. Both effects are of the same magnitude but of opposite sign; hence| climate modelling requires the full inclusion of aerosols. 3749,1992,2,4,GLOBAL WARMING AND ELECTRICITY DEMAND - A STUDY OF CALIFORNIA,In this paper we estimate changes in California's annual electricity use and peak demand by 2010 under two global warming scenarios. We use each warming scenario to produce an electricity demand projection with end-use energy models. Our analysis focuses on the heating and cooling of buildings and the pumping and transport of water for farms and cities. The results suggest global warming has a moderate effect on electricity demand. Under our worst scenario| a 1.9-degrees-C increase| we project Statewide electricity requirements will increase by about 7 500 GWh (2.6%) and 2 400 MW (3.7%). We conclude discussion with thoughts on the implications a warmer world may have for energy forecasters and resource planners. 3672,1992,2,4,GLOBAL WARMING AND ENVIRONMENTAL-CHANGE IN SUB-SAHARAN AFRICA,Now that governments are beginning to consider actions to respond to the potential threat of global warming (even if they do not yet believe that it will definitely occur)| their representatives search the scientific literature for 'clues' about the positive or negative impacts of a few degrees Celsius increase in global temperature. There is a growing number of 'guesstimates' (often called scenarios) about climate change impacts in sub-Saharan Africa. A review of the existing scenarios highlights conflicting| if not opposing| views about those impacts. Such scenarios must be used with caution and labelled as speculation. No single scenario should be used for determining irreversible policy responses to the potential regional consequences of global warming. 3691,1992,3,4,GLOBAL WARMING AND NUCLEAR-POWER,In view of the potential consequences of the greenhouse effect| it is important to restrain consumption of fossil fuels by exploiting conservation| solar power| and nuclear power. The pressure on developing countries for increased energy consumption makes reduction of fossil fuel use in the industrialized countries all the more important. Nuclear power already has had a significant impact. Primarily through its use| France reduced carbon dioxide emissions by 24% from 1973 to 1986. Given a vigorous program of nuclear power development| electrification| and conservation| one can envisage a U.S. energy economy in which CO2 production is halved. Standardized reactors| of small or medium size| may enhance the prospects for a nuclear renaissance in industrialized countries| and may be well matched to the needs of developing countries. 3742,1992,3,4,GLOBAL WARMING IMPLICATIONS OF REPLACING CFCS,The late 1980s were a challenging time for the HVAC and R industries because of the demands being made for increased energy efficiency| the development of alternative refrigerants that do not destroy stratospheric ozone| and the intense pressures of international competition. The 1990s will not be any less demanding| with further requirements to improve efficiency and changing understandings of environmental acceptability. Dealing with the global warming issue creates further difficulties in adapting the refrigeration and insulation technologies for future needs as chlorofluorocarbons are phased out of production and use in accordance with the Montreal Protocol. The study reported in this article was conducted to help industry| government and international policymakers reach sound decisions during the change-over from the CFCs to alternative compounds and technologies. Information developed in this effort complements ongoing studies to assess safety| toxicology| cost and other factors influencing these decisions.
2174,1992,4,4,GPS METEOROLOGY - REMOTE-SENSING OF ATMOSPHERIC WATER-VAPOR USING THE GLOBAL POSITIONING SYSTEM,We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is retrieved by stochastic filtering of the GPS data. Given surface temperature and pressure readings at the GPS receiver| the retrieved ZWD can be transformed with very little additional uncertainty into an estimate of the integrated water vapor (IWV) overlying that receiver. Networks of continuously operating GPS receivers are being constructed by geodesists| geophysicists| government and military agencies| and others in order to implement a wide range of positioning capabilities. These emerging GPS networks offer the possibility of observing the horizontal distribution of IWV or| equivalently| precipitable water with unprecedented coverage and a temporal resolution of the order of 10 min. These measurements could be utilized in operational weather forecasting and in fundamental research into atmospheric storm systems| the hydrologic cycle| atmospheric chemistry| and global climate change. Specially designed| dense GPS networks could be used to sense the vertical distribution of water vapor in their immediate vicinity. Data from ground-based GPS networks could be analyzed in concert with observations of GPS satellite occultations by GPS receivers in low Earth orbit to characterize the atmosphere at planetary scale.
3783,1992,3,3,GREENHOUSE GAS EMISSIONS FROM PASTURE AND ARABLE CROPS GROWN ON A KAIRANGA SOIL IN THE MANAWATU| NORTH ISLAND| NEW-ZEALAND,Carbon dioxide (CO2) emissions were determined during the first 3 years of cropping a Kairanga soil out of pasture| with either full cultivation or no-tillage cereal establishment. The CO2 emitted during cropping was compared with calculated methane production by ruminants grazing pasture at the site. Cultivation resulted in the loss of about 10 t soil organic carbon (C)/ha over 3 years but there was no change in soil C with no-tillage cropping. Grazing of pastures at a high but sustainable stocking rate was calculated to produce 205 kg C/ha per year as methane (CH4). No-tillage cropping of this site therefore contributes much less CH4 and CO2 to the atmosphere than either grazing or cropping with cultivation. Using 20-year global warming potentials of 20 and 1 for CH4 and CO2 respectively| the data showed that ruminants grazing this site would have had more influence on atmospheric warming than cropping with cultivation did. 3751,1992,2,3,GREENHOUSE WARMING OVER INDIAN SUBCONTINENT,A hierarchy of climate models have been developed and applied to the problem of doubling the CO2 concentration in the atmosphere. Currently available general circulation models include the most complete treatment of the global warming and are capable of providing changes in several of the meteorological parameters in time scales of half a century or even more. Much skill is gradually being achieved now for future climate simulations. In this paper| we have attempted to describe the response of the National Center for Atmospheric Research Climate Community Model (NCAR CCM)| whose performance for northern hemispheric climate simulations was reported to be very satisfactory to Indian region. The seasonal (winter and summer) changes in surface temperature| rainfall and soil moisture expected over the Indian sub-continent due to doubling of CO2 in the atmosphere as inferred from model output statistics are discussed. A probable scenario for sea level rise along the Indian coastline by the year 2030 AD as a result of ocean water's expansion due to global warming is outlined. These projections should not be treated as predictions of what is going to happen over the Indian sub-continent. Rather| they merely illustrate to what extent we might be affected by the future climate change. 2196,1992,2,4,GROWING-SEASON TRENDS IN THE ALASKAN CLIMATE RECORD,Linkages between presumed global climate change and agricultural production will enable the development of management strategies to meet the needs of a diverse and future world agricultural enterprise. This study evaluated characteristic trends in the growing season length and dates of the last spring and first fall freezes at eight climate stations in Alaska between 1924 and 1989. Two minimum temperature criteria of O-degrees and -3-degrees-C were used in assessing freeze dates. Half of the stations had no change in growing season length over the last 65 years. whereas the other four stations had a lengthening of the season. Tendencies for longer seasons were in part a result of earlier spring freezes. The growing season shortened at three stations during the period 1940-70. which corresponded with declining Northern Hemisphere temperatures. The presence of changes in the growing season over the last 65 years was apparent in Alaska temperature records.
3780,1992,3,2,HALOCARBONS AND GLOBAL WARMING,The production of chlorofluorocarbons (CFCs)| contributing both to the deterioration of the ozone layer and to the greenhouse effect| will be reduced in the near future. Hydro(chloro)-fluorocarbons| H(C)FCs| having a relatively low or no ozone depletion potential| are expected to partially replace CFCs. However| these H(C)FCs vary in global warming potential (GWP). Two groups can be distinguished: Class I H(C)FCs (HCFC-22| HCFC-142b| HFC-125| HFC-134a and HFC-143a) have a relatively high GWP| and Class II H(C)FCs (HCFC-123| HCFC-124| HCFC-141b and HFC-152a) have a relatively low GWP. In this study| using a 0-dimensional computer model| temperature forcing by halocarbons between 1985 and 2100 is calculated assuming different production scenarios for the halocarbons: CFCs| H(C)FCs| CH3CCl3 and CCl4. The results indicate that| while strongly restricting the use of CFCs| the most important factors determining the impact of halocarbons on future global warming may be the choice of H(C)FCs and the presence or absence of restrictions on H(C)FC applications. Unrestricted use of H(C)FCs exclusively from Class I could| by 2100| result in an equilibrium temperature increase that is 0.28-0.66-degrees-C higher than that resulting from the use of Class II H(C)FCs. However| if there is a phase-out of CFCs and Class I H(C)FCs by 2000| and if Class II H(C)FCs are only used as well-conserved refrigerants| the long-term climatic impact of halocarbons could become lower than the present impact of halocarbons. The same holds if there is a rapid total phase-out of radiatively active halocarbons. 3750,1992,3,3,HALOCARBONS AND GLOBAL WARMING .2.,Halocarbons| especially the widely used fully halogenated chlorofluorocarbons (CFCs) and chlorobromocarbons (halons)| contribute both to the deterioration of the ozone layer and the greenhouse effect. The use of CFCs and halons| however| will be restricted in the near future. Hydro(chloro)fluorocarbons [H(C)FCs]| which are less of a threat to the ozone layer| are expected to replace CFCs and halons. This study investigates the impact of CFCs| halons and H(C)FCs on global warming using an improved 0-dimensional computer model. The results indicate that implementation of the renewed Montreal Protocol may result in an equilibrium temperature increase at the earth's surface of 0.38-0.75-degrees-C by 2100 when H(C)FCs are used unrestrictedly to replace CFCs and halons. This warming can be reduced by 40% by better housekeeping| recycling or destruction of halocarbon wastes. A phase-out of HCFCs by 2035| which is under discussion as an additional measure to protect the ozone layer| could increase temperature forcing by halocarbons to 0.46-1.16-degrees-C| if HCFCs are replaced by HFCs and no emission-reducing measures are implemented. A phase-out of H(C)FCs with a relatively high global warming potential| while using H(C)FCs with a relatively low global warming potential only restrictedly and with extensive control technology| may result in equilibrium warming that is lower than the present forcing. However| stabilization of the temperature of the earth as influenced by halocarbons is approached most closely when all halocarbons are phased out before the end of this century. 3755,1992,3,3,HALOCARBONS AND GLOBAL WARMING .3.,This study investigates the impact of halocarbon use on global warming during the next century. An improved 0-dimensional computer model is used to calculate annually until 2100 the equilibrium temperature at the earth's surface as determined by halocarbons| following the expected application of specific halocarbons having a significant global warming potential. Halocarbon applications that contribute most to temperature forcing are calculated to be refrigeration and mobile air conditioning| if H(C)FCs are used unrestrictedly to replace CFCs and halons. The gases that are expected to contribute most to calculated temperature forcing are HCFC-22 and HFC-134a. If HCFCs are phased-out to protect the ozone layer and replaced by HFCs| HFC-134a| -143a and -125 will be the most important contributors to global warming| being mainly emitted from refrigeration and mobile air conditioning appliances. 3781,1992,3,4,HCFC BLOWN RIGID POLYURETHANE FOAMS AND REFRIGERATOR LINER MATERIALS - THE SEARCH FOR COMPATIBLE SYSTEMS,With the traditional use of CFC-11 blown polyurethane foam for refrigerator insulation there has been limited need for interaction between the PU producers on the one hand and the producers of plastics used for liner materials on the other hand. Taking into consideration their ozone depletion potential (ODP) and global warming potential (GWP) there is wide acceptance that HCFC-123 and -141b are the nearest "drop in" substitutes known today for CFC-11 replacement. However| this has major implications as these new blowing agents are significantly more aggressive requiring novel approaches in terms of material choice for monolithic and/or co-extruded sheet to retain the optimum sheet thickness| productivity and economics of current materials. This paper first of all summarises the current status of developments towards the reduction and eventual elimination of CFC-11 from rigid polyurethane foam systems used for the insulation of domestic refrigerators and freezers. It then addresses the problems of liner/alternative blowing agent interactions using tests which attempt to bridge the classical laboratory tests whilst acknowledging the ultimate need to run full scale processing| assembly and functional performance trials at refrigerator manufacturers. Key parameters covered include thermal conductivity| its ageing| carbon dioxide permeability and adhesion between the polyurethane foam and the plastic liner. Physical attack of the liners is studied employing two qualitative testa One involves an unconstrained situation with profiled vacuum formed liner in contact with HCFC blown foams; the other uses a prototype tool which incorporates shelf support and mullion in a restrained mode with an aluminium tool. New liner materials and combinations which are compatible with HCFC blown foams are identified as a result of this work. 3778,1992,2,4,HYDRAULIC RESIDENCE TIMES FOR THE LAURENTIAN GREAT-LAKES,The Laurentian Great Lakes comprise one of the major water resources of North America. For many water quality studies the hydraulic residence times or replacement times of the Great Lakes serve as measures of how quickly water quality will change in response to changes in contaminant loadings. The residence time for a conservative substance represents the average time a conservative substance which remains dissolved in the water spends in a lake. The hydraulic residence times of conservative substances for the Great Lakes are relatively long ranging| from close to 200 years for Lake Superior to a little over 2 years for Lake Erie. A major reduction of 38 years was found in the residence time for Lake Michigan (62 years as compared with the 100 year value previously reported) due to the consideration of flow exchange between Lakes Michigan and Huron. This indicates that Lake Michigan may respond much faster to reductions in contaminant loadings than previously expected. Because of their low ratio of volume to outflow| only Lakes Erie and Ontario are affected by normal climatic variations of less than 20 years in duration. Extreme lake level conditions over the period of 2 to 8 years can also significantly affect the residence times of Lakes Erie and Ontario. Thus high levels in the early 1970s may have contributed to the improvement of water quality in Lake Erie. Existing diversions and potential global warming appear to have no significant effect on residence times. 2204,1992,3,4,IEA PERSPECTIVES ON THE GLOBAL CLIMATE CHANGE ISSUE,Based on the IEA's Medium Term Model which provides estimates of energy consumption and related variables to the year 2005| the IEA has attempted to develop a coherent methodology to quantify approximately the possible effectiveness of response measures in achieving the target of stabilising of CO2 emissions at current levels by 2005. Such an analysis by no means constitutes a full cost benefit evaluation and does not try to measure the economic or other costs of the measures it evaluates. Also| it should not be viewed as a recommendation or suggestion on how best to counter the long-term accumulation of CO 2 emissions. Two types of policy instrument have been assessed: fiscal; and regulation of supply options. The study has evaluated four variants: carbon taxes; a 50% increase in nuclear's share of power generation; a combination of these two measures; and a radically greater use of natural gas.
3767,1992,3,3,IMPACT OF AIRCRAFT AND SURFACE EMISSIONS OF NITROGEN-OXIDES ON TROPOSPHERIC OZONE AND GLOBAL WARMING,ACTUAL and potential increases in aircraft traffic are causing concern about the effects of aircraft exhaust emission on atmospheric chemistry. Model results 1-3 and measurements 4-6 in the Northern Hemisphere have shown that growth in surface emissions of nitrogen oxides and hydrocarbons leads to increases in concentration of tropospheric ozone. Tropospheric ozone is toxic to plants| humans and other organisms| and it is a greenhouse gas 7-9. The radiative forcing of surface temperature is most sensitive to changes in tropospheric ozone at a height of approximately 12 km (ref. 8)| where aircraft emissions of nitrogen oxides are at a maximum and where the model sensitivity of ozone to nitrogen oxide emissions is enhanced. Our model results show that the radiative forcing of surface temperature is about thirty times more sensitive to aircraft emissions of nitrogen oxides than to surface emissions. We also find that the impact on global warming of increases in tropospheric ozone caused by increases in surface emissions of nitrogen oxides has previously been overestimated by a factor of five 1|10| owing to an error in the calculation of the ozone budget. 2207,1992,2,4,IMPACTS OF CLIMATE CHANGE AND SEA-LEVEL RISE ON SMALL ISLAND STATES - NATIONAL AND INTERNATIONAL RESPONSES,Few developing countries possess sufficient indigenous financial and personnel resources to address adequately the predicted impacts of global climate change. In recognition of this fact| the Oceans and Coastal Areas Programme Activity Centre of the United Nations Environment Programme (UNEP) in 1987 established a series of regional teams to examine potential impacts of climate change and sea-level rise on terrestrial and marine ecosystems| on coastal environments| and on the socioeconomic structures of countries throughout the world. Drawing mainly on the work of the South Pacific Task Team| this article provides an overview of interrelated environmental problems and development problems in the Indo-Pacific region and reviews efforts to develop response strategies. The case of the Maldives is highlighted.
3684,1992,2,3,IMPACTS OF CLIMATIC-CHANGE ON RIVER FLOW REGIMES IN THE UK,Much has been written in recent years about the potential threats posed by increasing greenhouse gas concentrations. This paper summarizes the implications of global warming for hydrological processes in general and river flow characteristics in the UK in particular| emphasizing the present high degree of uncertainty. Current climate change scenarios for the UK imply that rainfall between autumn and spring will increase| and this may have beneficial implications for UK water resources. However| the effect of this increase may be outweighed by higher evapotranspiration. Average annual runoff in a catchment in southern UK may be reduced by around 5% by the middle of the next century| but this estimate is very uncertain: runoff may reduce by 30% or increase by 30%. Runoff in northern and western UK is likely to show a slight increase (but with similarly large confidence intervals). It is probable that river flows in the UK will be much more concentrated in winter than at present. The effect of a given climate change scenario on monthly flow regimes depends on the current summer water balance and on catchment geological conditions. 3648,1992,2,1,IMPLICATIONS FOR GLOBAL WARMING OF INTERCYCLE SOLAR IRRADIANCE VARIATIONS,FOLLOWING earlier studies1-6| attention has recently been directed again to the possibility that long-term solar irradiance variations| rather than increased greenhouse gas concentrations| have been the dominant cause of the observed rise in global-mean surface temperature from the mid-nineteenth century to the present. Friis-Christensen and Lassen7 report a high correlation (0.95; ref. 8) between the variable period of the '11-year' sunspot cycle and the mean Northern Hemisphere land surface temperature from 1865 to 1985. The Marshall Institute report9 concludes that '...the sun has been the controlling influence on climate in the last 100 years| with the greenhouse effect playing a smaller role." Here we explore the implication that such putative solar irradiance variations would have for global warming. Our results provide strong circumstantial evidence that there have been intercycle variations in solar irradiance which have contributed to the observed temperature changes since 1856. However| we find that since the nineteenth century| greenhouse gases| not solar irradiance variations| have been the dominant contributor to the observed temperature changes. 2200,1992,2,4,INADVERTENT WEATHER-MODIFICATION IN URBAN AREAS - LESSONS FOR GLOBAL CLIMATE CHANGE,Large metropolitan areas in North America| home to 65% of the nation's population| have created major changes in their climates over the past 150 years. The rate and amount of the urban climate change approximate those being predicted globally using climate models. Knowledge of urban weather and climate modification holds lessons for the global climate change issue. First| adjustments to urban climate changes can provide guidance for adjusting to global change. A second lesson relates to the difficulty but underscores the necessity of providing scientifically credible proof of change within the noise of natural climatic variability. The evolution of understanding about how urban conditions influence weather reveals several unexpected outcomes| particularly relating to precipitation changes. These suggest that similar future surprises can be expected in a changed global climate| a third lesson. In-depth studies of how urban climate changes affected the hydrologic cycle| the regional economy| and human activities were difficult because of data problems| lack of impact methodology| and necessity for multidisciplinary investigations. Similar impact studies for global climate change will require diverse scientific talents and funding commitments adequate to measure the complexity of impacts and human adjustments. Understanding the processes whereby urban areas and other human activities have altered the atmosphere and changed clouds and precipitation regionally appears highly relevant to the global climate-change issue. Scientific and governmental policy development needs to recognize an old axiom that became evident in the studies of inadvertent urban and regional climate change and their behavioral implications: Think globally but act locally. Global climate change is an international issue| and the atmosphere must be treated globally. But the impacts and the will to act and adjust will occur regionally.
3658,1992,3,4,INDUSTRIAL-INNOVATION AND GOVERNMENT ENVIRONMENTAL-REGULATION - SOME LESSONS FROM THE PAST,While government regulatory activity of all kinds was at historically high levels between the mid-1960s and the mid-1970s| the following decade saw a strong trend towards deregulation. Since the mid-1980s| with the increasingly obvious detrimental impact of environmental pollution and growing fears over ozone layer depletion and global warming| there have been strong pressures for more stringent environmental regulations. During the earlier period of intense regulatory activity| government regulations frequently had unnecessarily large negative impacts on regulated firms. This paper addresses a number of these impacts and their underlying causes and suggests how the negative effects of environmental regulations can be minimized while at the same time offering adequate protection to the environment. 3657,1992,4,4,INFERENCE ABOUT TRENDS IN GLOBAL TEMPERATURE DATA,Interpretation of the effects of increasing atmospheric carbon dioxide on temperature is made more difficult by the fact that it is unclear whether sufficient global warming has taken place to allow a statistically significant finding of any upward trend in the temperature series. We add to the few existing statistical results by reporting tests for both deterministic and stochastic non-stationarity (trends) in time series of global average temperature. We conclude that the statistical evidence is sufficient to reject the hypothesis of a stochastic trend; however| there is evidence of a trend which could be approximated by a deterministic linear model. 3699,1992,3,3,INFLUENCE OF KAOLIN ON METHANE OXIDATION BY METHYLOMONAS-METHANICA IN GAS-PHASE BIOREACTORS,Significant levels of methane are liberated from the coal face and subterranean pockets during coal mining. This methane poses an explosion hazard in mines and when released into the atmosphere| acts as a greenhouse gas which contributes to global warming. Methanotrophic bacteria in gas phase bioreactors (GPBs) offer the potential to convert this methane to less deleterious substances; however| it is critical that reaction rates be maximized. The effect of kaolin on rates of methane oxidation by Methylomonas methanica grown in GPBs was assessed. The amendment of GPBs with a 4% kaolin solution significantly increased methane removal by M. methaniea versus non-kaolin-amended controls. The maximum velocities (upsilon(max)) were 604.1 mg methane min-1 GPB-1 in the control compared to 1156.6 mg methane min-1 GPB-1 in the kaolin-amended bioreactors| while the Michaelis constants (K(m)) were 15.87 and 60.52 mg methane GPB-1| respectively. 2208,1992,3,3,INSTITUTIONS FOR MANAGING GLOBAL CLIMATE CHANGE - COMPLIANCE| FAIRNESS| AND UNIVERSAL PARTICIPATION,Ensuring that treaties designed to manage global climate change are 'implementable' is an important negotiating challenge. Implementable agreements have a reasonable chance of being ratified by nation states that are the greatest contributors to the problem; are acceptable to parties with the resources to do something about it; and induce voluntary compliance. This article contends that| aside from domestic political characteristics| other factors contributing to effective implementation of international agreements are their structure| requirements| and expectations. Factors that optimize implementable agreements include: a sufficient number of relevant participants in negotiations to enhance their legitimacy; reliance on confidence-building to deter non-compliance; stating precisely the signatory obligations; and designing treaties to be renegotiable in the face of changing scientific| political| and economic conditions. Global environmental agreements most likely to obtain signatory compliance will avoid overly stringent standards; allow variable compliance and discretion in implementation; consult domestic interests at each stage of agreement 'design' and execution; permit transfers of resources and technology; and rely on 'functional integration' to build confidence.
2219,1992,4,2,INTERACTIONS BETWEEN HYDRODYNAMICS AND PELAGIC ECOSYSTEMS - RELEVANCE TO RESOURCE EXPLOITATION AND CLIMATE CHANGE,A proposal is made to classify the pools of biogenic carbon in the oceans by reference to their turnover times. Break points in the continuum of turnover times| located at 10(-2) and 10(2) years| distinguish between short-lived organic carbon| long-lived organic carbon and sequestered biogenic carbon. The three pools of biogenic carbon are discussed by reference to the more usual oceanographic concepts of new v. regenerated production| and export v. recycled production. Short-lived organic carbon is mainly associated with the microbial food-loop| long-lived organic carbon is relevant to renewable marine resources| and sequestered carbon is pertinent to global climate change (greenhouse effect). Recycling| export and sequestration are controlled by the proportions of primary production effected by small (<5 mum) and large (>5 mum) phytoplankton respectively| and by the selective grazing pressure experienced by cells in the various size-classes. These ecosystem processes are in turn governed by hydrodynamics. At low levels of auxiliary (mechanical) energy| the physical environment is stable. so that pelagic ecosystems are dominated by the microbial food-loop and biogenic carbon is mainly short-lived. Transitions from high levels of auxiliary energy to more stable conditions favour the production of large phytoplankton. When this takes place along predictable regular modes| primary production may be channelled into the long-lived pool| whereas stochastic transitions may lead to carbon sequestration. This theoretical framework may help the modem approaches of fisheries oceanography and biogeochemical oceanography to converge.
3671,1992,2,3,INTERANNUAL VARIABILITY OF LANDFAST ICE THICKNESS IN THE CANADIAN HIGH ARCTIC| 1950-89,A physical one-dimensional heat transfer model of fast ice growth was used to investigate the interannual variability of maximum fast ice thickness at four sites in the High Arctic over the period 1950-89. The insulating role of snow cover was found to be the most important factor| explaining 30-60% of the variance in maximum ice thickness values. Other snow-related processes such as slushing and density variations were estimated to explain a further 15-30% of the variance. In contrast| annual variation in air temperatures explained less than 4% of the variance in maximum ice thickness. No evidence was found for the systematic ice thinning trend anticipated from greenhouse gas-induced global warming. However| recent ice thinning and thickening trends at two sites (Alert and Resolute) are consistent with changes in the average depth of snow covering the ice and may be explained by changes in cyclone frequencies. A response surface sensitivity analysis following Fowler and de Freitas (1990) indicated the High Arctic landfast ice regime would be more sensitive to air temperature variations under a warmer| snowier environment. 3761,1992,4,4,INTERDECADAL NATURAL CLIMATE VARIABILITY IN THE WESTERN PACIFIC AND ITS IMPLICATION IN GLOBAL WARMING,Long-term hydrographic observations repeated by the Japan Meteorological Agency in the western Pacific have revealed not only the oceanic thermal variability associated with the ENSO events but also another interdecadal variability seemingly related to the global warming trend from the late 1970s. Since the background SST is high in the tropical western Pacific| even weak SST anomalies may affect strongly the atmospheric circulation including the Aleutian Low and the Asian winter monsoon. The extratropical atmospheric response to the interdecadal SST anomaly is global and looks quite different from that for the ENSO time scale. We note that the response is even reversed in the Asian monsoon region. To the west of the date line the ocean behaves like a dynamical slave to the winter Asian monsoon as demonstrated using the ocean general circulation model. In particular| the winter monsoon and related easterly wind variations are responsible for maturity or immaturity of the cold Mindanao Dome off the Phillipine coast. However| the active (inactive) summer monsoon followed by the anomalous easterlies (westerlies) intensified over the tropical western Pacific from summer through winter appears to be responsible for the positive (negative) SST anomalies in the same area at least for the ENSO time scale. This suggests that an interesting positive feedback mechanism responsible for natural climate variabilities ranging from several years to decades may exist in the coupled ocean-atmosphere-land system in the western tropical Pacific. 3779,1992,4,4,INTERHEMISPHERIC CONTRASTS OF MEAN GLOBAL TEMPERATURE ANOMALIES,Northern and Southern Hemisphere series of surface temperature anomalies are compared. The series studied are the University of East Anglia Climatic Research Unit (CRU) monthly series (1854-1986) and the UK Meteorological Office (MO) quarterly series (1856-1989). A major difference is the marked seasonal variation of the warming trend in the Northern Hemisphere| with maximum in winter and minimum in summer. Analysis of the annual cycle of the CRU set suggests a shift in phase of the warm peak in the annual cycle of temperature anomalies from July to January for the period. This shift is a characteristic of the annual cycle itself and does not have to be associated with a greater warming trend in winter than in summer| although it may be. The series were converted into interannual differences from one month or quarter to the corresponding month or quarter in the following year. Globally| the sequential values of the positive and negative modes of the interannual differences suggest a slow relaxation towards zero with the absolute values of the interannual coolings decreasing faster than those of the interannual warmings. Spectral analyses of the first-order interannual differences of the monthly CRU and of the quarterly MO series suggest that the temperature field reacts to a Quasi-Biennial Oscillation pulse in the Northern Hemisphere and to a stronger ENSO pulse in the Southern Hemisphere. 3760,1992,3,4,INVESTIGATIONS OF THE ENVIRONMENTAL ACCEPTABILITY OF FLUOROCARBON ALTERNATIVES TO CHLOROFLUOROCARBONS,Chlorofluorocarbons (CFCs) are currently used in systems for preservation of perishable foods and medical supplies| increasing worker productivity and consumer comfort| conserving energy and increasing product reliability. As use of CFCs is phased out due to concerns of ozone depletion| a variety of new chemicals and technologies will be needed to serve these needs. In choosing alternatives| industry must balance concerns over safety and environmental acceptability and still meet the performance characteristics of the current CFC-based products. About 60% of projected CFC demand will either be eliminated by improved conservation practices or will be satisfied by nonfluorocarbon alternatives. With current technology| the only viable alternatives meeting the safety| performance| and environmental requirements for the remaining 40% of demand are fluorocarbons| hydrochlorofluorocarbons (HCFCs)| and hydrofluorocarbons (HFCs). HCFCs and HFCs possess many of the desirable properties of the CFCs| but because of the| hydrogen| they react with hydroxyl in the lower atmosphere. This results in shorter atmospheric lifetimes compared to CFCs and reduces their potential to contribute to stratospheric ozone depletion or global warming; HFCs do not contain chlorine and have no potential to destroy ozone. This paper provides an overview of challenges faced by industry| regulators| and society in general in continuing to meet societal needs and consumer demands while reducing risk to the environment without compromising consumer or worker safety. 3668,1992,5,4,IRREGULAR OSCILLATIONS OF THE WEST ANTARCTIC ICE-SHEET,Model simulations of the West Antarctic ice sheet suggest that sporadic| perhaps chaotic| collapse (complete mobilization) of the ice sheet occurred throughout the past one million years. The irregular behaviour is due to the slow equilibration time of the distribution of basal till| which lubricates ice-sheet motion. This nonlinear response means that predictions of future collapse of the ice sheet in response to global warming must take into account its past history| and in particular whether the present basal till distribution predisposes the ice sheet towards rapid change. 3715,1992,2,4,ISOLATION AND DETERMINATION OF CULTURAL-CHARACTERISTICS OF MICROALGAE WHICH FUNCTIONS UNDER CO2 ENRICHED ATMOSPHERE,A fresh-water microalgae| which functions under CO2 enriched atmosphere conditions| was isolated and its cultural characteristics were investigated. The HA-1 strain| identified as genus Chlorella| was newly isolated from a paddy field by an enrichment culture using reproduced stack gases from a thermal power plant with a concentration of CO2 and O2 of 15 % and 2 % respectively. It showed maximum growth at 10 % CO2 enriched air flowing condition| and showed a good growth rate in a broad range of physically controllable conditions| including CO2 enriched air flow rate| temperature and pH value. The results indicated the feasibility of the HA-1 strain for mass cultivation using stack gases. 2181,1992,3,4,ISRAELI RESEARCHERS PLANNING FOR GLOBAL CLIMATE CHANGE ON THE LOCAL-LEVEL - GREENING THE DESERT IS NOT A SENSIBLE OPTION GIVEN LIMITED WATER,Greening the desert is not a sensible option given limited water The dream to 'green the Negev' has been part of the Israeli psyche since the state was established| but Israel's plans to conquer its deserts were rather naive| say its scientists today. Bringing in enough water can transform a desert| but the system's productivity lasts only as long as the water. And water is an unreliable variable in Israel. The Sea of Galilee supplies approximately half the drinking water for more than 5 million people and 20-30% of the total water used. Two years ago| water levels in the lake dropped within centimeters of the "red line." A drop below the line would pose a potential disaster. Fortunately| last year's unusually heavy precipitation raised the lake's waters to its highest levels since 1988. Such vagaries have forced the country to alter its water use patterns and attitudes toward greening. The Jewish National Fund| for example| originally aimed to plant dense stands of trees throughout Israel. "But I convinced [the fund] that without irrigation you cannot turn a desert into a forest|" Moshe Shachak| a researcher at the Mitrani Center for Desert Ecology at the Ben-Gurion University of the Negev| said in an interview in his laboratory recently. Much of the development in the Negev Desert has depended on piping water great distances from other parts of the country. The fund now supports research on a landscape management technique called savannization| which is being developed at Mitrani. By using the technique| areas that may not normally support trees and a wide variety of annuals due to climatic factors like rainfall could be converted to a more diverse landscape without bringing water in from outside the region| says …
3696,1992,4,4,KINETICS OF THE OH REACTION WITH METHYL CHLOROFORM AND ITS ATMOSPHERIC IMPLICATIONS,The rate coefficients for the reaction of hydroxyl (OH) radicals with methyl chloroform (CH3CCl3) were measured between 243 and 379 kelvin with the pulsed photolysis-laser-induced fluorescence method. The measured rate Coefficients at 298 and 277 kelvin were approximately 20 and approximately 15%| respectively| lower than earlier values. These results will increase the tropospheric OH concentrations derived from the CH3CCl3 budget analysis by approximately 15%. The predicted atmospheric lifetimes of species whose main loss process is the reaction with OH in the troposphere will be lowered by 15% with consequent changes in their budgets| global warming potentials| and ozone depletion potentials. 3689,1992,4,4,LAKE ICE RECORDS USED TO DETECT HISTORICAL AND FUTURE CLIMATIC CHANGES,Historical ice records| such as freeze and breakup dates and the total duration of ice cover| can be used as a quantitative indicator of climatic change if long homogeneous records exist and if the records can be calibrated in terms of climatic changes. Lake Mendota| Wisconsin| has the longest uninterrupted ice records available for any lake in North America dating back to 1855. These records extend back prior to any reliable air temperature data in the midwestern region of the U.S. and demonstrate significant warming of approximately 1.5-degrees-C in fall and early winter temperatures and 2.5-degrees-C in winter and spring temperatures during the past 135 years. These changes are not completely monotonic| but rather appear as two shorter periods of climatic change in the longer record. The first change was between 1875 and 1890| when fall| winter| and spring air temperatures increased by approximately 1.5-degrees-C. The second change| earlier ice breakup dates since 1979| was caused by a significant increase in winter and early spring air temperatures of approximately 1.3-degrees-C. This change may be indicative of shifts in regional climatic patterns associated with global warming| possibly associated with the 'Greenhouse Effect'. With the relationships between air temperature and freeze and break up dates| we can project how the ice cover of Lake Mendota should respond to future climatic changes. If warming occurs| the ice cover for Lake Mendota should decrease approximately 11 days per 1-degrees-C increase. With a warming of 4 to 5-degrees-C| years with no ice cover should occur in approximately 1 out of 15 to 30 years. 3763,1992,3,2,LEAKING METHANE FROM NATURAL-GAS VEHICLES - IMPLICATIONS FOR TRANSPORTATION POLICY IN THE GREENHOUSE ERA,A model of the U.S. automobile market is used to test the role that natural gas vehicles (NGVs) might play in reducing greenhouse-gas emissions. Since natural gas (primarily methane) emits less CO2 per unit of energy than petroleum products| NGVs are an obvious pathway to lower CO2 emissions. High- and low-demand scenarios are used to forecast the emissions from unrestricted growth and a modest program of conservation| respectively. Based on these scenarios| a reference scenario is developed that projects a possible future path of automobile use and efficiency. It is found that without a dramatic increase in automobile use| fuel consumption and greenhouse-gas emissions from automobiles in the United States will probably decrease in the future| provided that efficiency continues to improve at modest rates. In theory| NGVs can help shift emissions even further down. A second objective is to quantify the role that leaking methane might play in offsetting some of the greenhouse advantages of NGVs. To do this| a simple atmospheric chemistry model is applied to the reference scenario; several leak rates and feedback factors are used to test the sensitivity of the projected greenhouse forcing from now until 2050. Committed warming beyond 2050 is not included| and the results should be interpreted with that in mind. It is highly unlikely that switching automobiles from gasoline to natural gas will appreciably lower future greenhouse forcing. Constraints on vehicle miles travelled as well as continued improvements in vehicle efficiency will make a much larger contribution towards controlling global warming. 2173,1992,2,4,LONG-TERM RESPONSE OF AN ARCTIC SEDGE TO CLIMATE CHANGE - A SIMULATION STUDY,It appears that polar regions of the Ear-th will bear the brunt of global temperature increases. Because of the ecological importance of the sedge Eriophorum vaginatum in the arctic and the large amount ot data available on its growth and physiology| we chose this species as a test case to model the potential long-term response of arctic plants to global climate change. Our simulation model utilizes a mechanistic framework and includes the effects of light| temperature| season length| nitrogen availability| and CO2 concentration on E. vaginatum growth dynamics. The model was parameterized based on a series of published studies of the growth responses of E. vaginatum to nutrients and validated using (1) field studies on the growth responses of E. vaginatum to temperature and shading| and (2) the effects of elevated CO2 and temperature on E. vaginatum photosynthesis. The effect of a 50-yr period of climate change on peak biomass (overwintering biomass plus seasonal production) in E. vaginatum was explored. We use climate change here to refer to linear increases over a 50-yr period in temperature (from 8-degrees to 13-degrees-C)| season length (from 100 to 120 d)| and atmospheric CO2 (from 340 to 680 muL/L). Similarly| a wide range of nitrogen availabilities (from 9 to 18 g.m 2.vr-1) was also examined because of its importance in productivity. The model predicts that a simultaneous increase in the direct effects of temperature| season length| and CO2| with no change in nitrogen availability| will result in a slight decrease in peak biomass. A simulated long-term doubling of nitrogen availability results in an almost-equal-to 70% increase in peak biomass| whereas with concurrent changes in climate and nitrogen availability| the model predicts a slight decline in peak biomass compared to increases in nitrogen alone. In essence| the model predicts that climate change will have substantial effects on E. vaginatum only indirectly through changes in nitrogen availability. Simulated peak biomass responds linearly up to a doubling of current nitrogen availabilities. Therefore| at low-to-moderate increases in nitrogen availability| the predicted response of E. vaginatum to climate change is linearly (and almost exclusively) dependent on our ability to predict the effects of climate change on nitrogen cycling. At nitrogen availabilities > 2 x current availabilities| the relationship flattens out very rapidly because the plant becomes limited by carbon uptake. Thus| if nitrogen availabilities more than double in the future| E. vaginatum may shift from being a nutrient-limited to a carbon-limited system and| consequently| increased season length and elevated CO2 concentrations may play an important role in controlling E. vaginatum productivity.
3752,1992,3,2,MAKING BETTER USE OF CARBON .1. THE CARBON-DIOXIDE PROBLEM AND THE STEEL-INDUSTRY,It is becoming increasingly probable that emissions of carbon dioxide from the fossil fuels will have to be reduced to deal with the threat of global warming. This issue is likely to be resolved one way or the other in the period 1995 to 2000 which does not leave much time to develop responsive options. In the intervening period| the policy of the Government of Canada is to stabilize emissions of greenhouse gases at their 1990 level by 2000| by encouraging greater efficiency in the use of energy. Should further reductions prove necessary| economic instruments would probably be employed but these would not be applied before a comprehensive international agreement is reached. There are three main themes in this paper; it is assumed that measures to control carbon dioxide emissions will in fact be necessary by the turn of the century; that there will be a rising need for liquid fuels to supply the world's steadily growing fleet of motor vehicles for many years to come| and that the future niche for Canada's industry in such a carbon-constrained world will be the operation of the energy-intensive industries with efficiency and environmental sensitivity. The steel industry| as a large user of both coal and energy in other forms| would be significantly affected by a need to reduce carbon dioxide emissions. This paper first examines what might be called the conventional responses open to the industry in such a situation and then explores a new possibility for making better use of carbon by the co-production of iron and liquid fuels. 3741,1992,3,3,MAKING BETTER USE OF CARBON .2. THE COPRODUCTION OF IRON AND LIQUID FUELS,It is becoming increasingly probable that emissions of carbon dioxide from the fossil fuels will have to be reduced to deal with the threat of global warming. This issue is likely to be resolved one way or the other in the period 1995 to 2000 which does not leave much time to develop responsive options. In the intervening period| the policy of the Government of Canada is to stabilize emissions of greenhouse gases at their 1990 level by 2000| by encouraging greater efficiency in the use of energy. Should further reductions prove necessary| economic instruments would probably be employed but these would not be applied before a comprehensive international agreement is reached. There are three main themes in this paper: it is assumed that measures to control carbon dioxide emissions will in fact be necessary by the turn of the century; that there will be a rising need for liquid fuels to supply the world's steadily growing fleet of motor vehicles for many years to come| and that the future niche for Canada's industry in such a carbon-constrained world will be the operation of the energy-intensive industries with efficiency and environmental sensitivity. The steel industry| as a large user of both coal and energy in other forms| would be significantly affected by a need to reduce carbon dioxide emissions. This paper first examines what might be called the conventional responses open to the industry in such a situation and then explores a new possibility for making better use of carbon by the co-production of iron and liquid fuels. 3777,1992,4,4,MEASURES OF MARINE ENVIRONMENTAL-QUALITY,In the past| measures of marine environmental quality have focused on effects of specific stressors on ecosystem components-biochemical| genetic| physiological| pathological| behavioural and community. To measure ecosystem changes resulting from multiple stresses| such as a combination of pollutants (some local and some not) and physical habitat changes including those that might arise from global warming| it is necessary to measure attributes of whole ecosystems. These include primary productivity| nutrient cycling| species diversity| instability| disease prevalence| size spectrum and contaminant effects across trophic levels. Monitoring programmes should test hypotheses regarding changes in and effects on (a) processes| such as bioaccumulation| biomass production| respiration| reproduction and eutrophication that| if impaired| may lead to changes in ecosystem structure; and (b) the structure and key system attributes of marine ecosystems. 3678,1992,3,3,METHANE PREDICTION IN DRY AND LACTATING HOLSTEIN COWS,Data from six experiments (two with dry cows) were used to predict partitioning of gross energy to CH4 in Holstein cows using selected independent variables| some of which were intercorrelated| and a stepwise backward elimination regression procedure. Methane OutPuts ranged from 3.1 to 8.3% (mean 5.5) Of gross energy intake for 134 dry cow balance trials and from 1.7 to 14.9% (mean 5.2) of gross energy intake for 358 lactating cow energy balance trials. This is equivalent to 176 and 300 g/d or 245 and 419 L/d of cH4 for dry and lactating Holstein cows| respectively. Digestibilities Of hemicellulose and neutral detergent solubles were positive predictors| and cellulose digestibility was a negative predictor of CH4 output in dry cows fed all forage diets| but hemicellulose digestibility was not a significant variable for predicting CH4 production by lactating cows fed diets with concentrate and forages. Fiber digestibility generally remained in models to predict CH4 output. Except for one data set| regression equations accounted for 50 to 72% of the variation in percentage of gross energy partitioned to CH4 by Holstein cows. Results confirm that increased concentrate feeding reduces CH4 production. Supplementation of lactation diets with fat generally in fat digestibility| and this trait was associated with reduced CH4 output. Results enable 1) estimation of CH4 output for calculation of metabolizable energy and 2) computation of the contribution from dairy cows to global warming. 2217,1992,2,4,MODELING GLOBAL MACROCLIMATIC CONSTRAINTS ON ECTOTHERM ENERGY BUDGETS,We describe a mechanistic individual-based model of how global macroclimatic constraints affect the energy budgets of ectothermic animals. The model uses macroclimatic and biophysical characters of the habitat and organism and tenets of heat transfer theory to calculate hourly temperature availabilities over a year. Data on the temperature dependence of activity rate| metabolism| food consumption and food processing capacity are used to estimate the net rate of resource assimilation which is then integrated over time. We detail and explore the significance of assumptions used in these calculations. We present a new test of this model in which we show that the predicted energy budget sizes for 11 populations of the lizard Sceloporus undulatus are in close agreement with observed results from previous field studies. This demonstrates that model tests are feasible and the results are reasonable. Further| since the model represents an upper bound to the size of the energy budget| observed residual deviations form explicit predictions about the effects of environmental constraints on the bioenergetics of the study lizards within each site that may be tested by future field and laboratory studies. Three major new improvements to our modeling are discussed. We present a means to estimate microclimate thermal heterogeneity more realistically and include its effects on field rates of individual activity and food consumption. Second| we describe an improved model of digestive function involving batch processing of consumed food. Third| we show how optimality methods (specifically the methods of stochastic dynamic programming) may be included to model the fitness consequences of energy allocation decisions subject to food consumption and processing constraints which are predicted from the microclimate and physiological modeling. Individual-based models that incorporate macroclimatic constraints on individual resource acquisition| assimilation and allocation can provide insights into theoretical investigations about the evolution of life histories in variable environments as well as provide explicit predictions about individual| population and community level responses to global climate change.
3717,1992,3,4,MODELING THE RELEASE OF CO2 IN THE DEEP OCEAN,In order to better understand the mechanics of ocean disposal of CO2 captured from power plants| a comprehensive plume model was developed to simulate the dynamic| near-field behavior Of CO2 released in the water column as either a buoyant liquid or vapor. The key design variables in the model that can be controlled are: (1) release depth| z(o)| (2) number of diffuser ports| N| and (3) initial bubble or droplet radius| r(o). For a CO2 stream from a 500 MW power plant with 100% capture and z(o)=500 m| N=10| and r(o)=1 cm| the model predicts that the plume will rise less than 100 m. This will result in CO2 enrichment at depths greater than 400 m. Detailed predictions of local CO2 concentrations near the plume are presented and discussed. The issue of the residence time of the captured CO2 in the ocean is also addressed. We estimate a typical residence time of less than 50 years for releases of CO2 less than 500 m deep and| for a release depth of 1000 m| a residence time from 200 to 300 years. These residence times may be increased by releasing in areas of downwelling or by forming solid CO2-hydrates| which can sink to the ocean floor. 2187,1992,5,4,MODERN DISTRIBUTION OF DIATOMS IN SEDIMENTS FROM THE GEORGE-V-COAST| ANTARCTICA,Currently| little information exists concerning high frequency climate change in the Antarctic| data that are essential to gaining a more complete understanding of global climate change. Sediments from the George V Coast continental margin potentially contain a high resolution record of the late Holocene. The relatively high rate of sedimentation (approximately 3 mm/year) and the presence of laminated intervals which contain undisturbed sequences make these sediments valuable for future downcore work. In order to utilize diatom assemblages as proxies of paleoclimatic and paleoceanographic parameters| a preliminary study of the surface sediment distribution of diatoms from the George V Coast continental margin was completed. Nitzschia curta (Van Heurck) Hasle and Nitzschia kerguelensis (O'Meara) Hasle present great potential for tracking the Holocene retreat of ice across the continental shelf of this region. Concentrations of N. curta| an "ice-related" form| decreases in an offshore direction| whereas N. kerguelensis| an "oceanic" species associated with circumpolar flow| displays an increase in sediments offshore. The genus Thalassiosira Cleve displays a clear association with areas of open water primary production| as has been noted in others parts of the Antarctic. Downcore variability in relative abundance of this genus will be useful in understanding the history of sea ice versus open water production on the George V Coast shelf. In contrast| the distribution of Chaetoceros Ehrenberg resting spores appears to be more complex| but may be related to the position of the stationary ice edge associated with the annual minimal extent of sea ice. Finally| an understanding of the downcore variability of Thalassiothrix antarctica Schimper ex Karsten| a species which is very abundant in the laminated sections of the sediment cores| will have to rely on studies of its distribution in other areas of the Antarctic| as it is sparsely distributed along the George V Coast today.
3769,1992,3,3,NITROUS-OXIDE EMISSIONS IN IRRIGATED CORN AS AFFECTED BY NITRIFICATION INHIBITORS,Nitrous oxide and N2 are the major denitrification products in irrigated corn (Zea mays L.). In addition| N2O is considered a gas that contributes to global warming and stratospheric O3 depletion. Minimizing N2O emissions in cropping systems is therefore an economic as well as an important environmental concern. In a 1989 field experiment| the nitrification inhibitor encapsulated calcium carbide (ECC) (0| 20| or 40 kg CaC2 ha-1) or nitrapyrin (0.5 L a.i. ha-1) was banded with urea (218 kg N ha-1) 7 wk after planting corn. Between 1 and 14 wk after fertilization in 1989| N2O losses of 3226| 1109| 1017| and 1005 g N2O-N ha-1 from urea alone| urea plus nitrapyrin| urea plus 20 kg ECC ha-1| and urea plus 40 kg ECC ha-1| respectively| were measured from vented chambers. Nitrous oxide fluxes were positively correlated with soil NO3 levels| indicating that the nitrification inhibitors indirectly controlled N2O emissions by preventing NO3 from accumulating in the soil. Carbon dioxide emissions from the root zone were generally not affected by ECC or nitrapyrin. In 1990| losses of N2O were less than in 1989 (1651 g N ha-1 with urea alone)| probably because there were fewer irrigations. Nitrapyrin and ECC addition to urea resulted in 980 and 459 g N ha-1 N2O being emitted the second year. Nitrification inhibitors appear to be a useful tool in mitigating N2O emissions in agricultural systems. 2218,1992,3,4,ON AN INTERNATIONAL FRAMEWORK CONVENTION ON CLIMATE CHANGE - GLOBAL CLIMATE CHANGE IN THE CONTEXT OF GLOBAL CHANGE,The report prepared by the Intergovernmental Panel on Climate Change (IPCC) for the Second World Climate Conference contains well-weighted assessments of the present-day state of climate studies and of the possible consequences of climate change. Since IPCC's report is supposed to be a basis for working out an International Framework Convention on Climate Change| an analysis has been made of a number of drawbacks in the consideration of the biosphere as an interactive component of the climatic system| as well as of socio-economic impacts of biospheric changes on climate change. Some thoughts have been expressed on the key components of a convention on climate change.
3700,1992,2,4,ON THE ABRUPT CHANGE IN SOUTH ASIAN SUMMER MONSOON CLIMATE AND ITS SYNCHRONISM WITH THE GLOBAL RAPID WARMING,This paper has analysed the major characteristics of long-term variation of summer monsoon climate in South Asia since 1888. An abrupt enhancement of summer monsoon in the 1920s and its synchronism with the global rapid warming have been detected by the Mann-Kendall Rank Statistic test. Based on diagnostic analysis on the atmospheric circulation over the monsoon region and the thermal conditions of both ocean and land during the period of abrupt change| it is found that the warming over land was stronger and earlier than that over the ocean| which would enhance the land-sea thermal contrast and therefore be favorable to the development of monsoon low and the disturbance in the monsoon flow. This may be a direct factor for the abrupt enhancement of summer monsoon. 3788,1992,3,2,OPTIONS FOR REDUCING CO2 EMISSIONS FROM PERSONAL TRAVEL IN EUROPE,Personal travel is an increasingly important aspect of European society. Our demand for travel| in terms of time| money and mobility| is steadily increasing. This growth has led to a number of undesirable effects| including a substantial contribution to global warming through the emission of carbon dioxide (CO2). To address this issue| a number of solutions are available. Already the technology is established for highly economical cars| but experience shows that incentives or regulations are required in order to stimulate widespread interest in saving fuel. Similarly. alternative fuels can offer considerable reductions in greenhouse emissions| depending on the source of the energy. In the longer run| it is essential that technological measures are complemented by policies to reduce the need to travel| whilst still maintaining accessibility. This paper presents a list of policies that are being investigated as pan of a strategy for reducing CO2 emissions from personal travel in Britain. 3721,1992,5,3,PANGAEAN CLIMATE DURING THE EARLY JURASSIC - GCM SIMULATIONS AND THE SEDIMENTARY RECORD OF PALEOCLIMATE,Results from new simulations of the Early Jurassic climate show that increased ocean heat transport may have been the primary force generating warmer climates during the past 180 m.y. The simulations| conducted using the general circulation model (GCM) at the Goddard Institute for Space Studies| include realistic representations of paleocontinental distribution| topography| epeiric seas| and vegetation| in order to facilitate comparisons between model results and paleoclimate data. Three major features of the simulated Early Jurassic climate include the following. (1) A global warming| compared to the present| of 5-degrees-C to 10-degrees-C| with temperature increases at high latitudes five times this global average. Average summer temperatures exceed 35-degrees-C in low-latitude regions of western Pangaea where eolian sandstones testify to the presence of vast deserts. (2) Simulated precipitation and evaporation patterns agree closely with the moisture distribution interpreted from evaporites| and coal deposits. High rainfall rates are associated primarily with monsoons that originate over the warm Tethys Ocean. Unlike the "megamonsoons" proposed in previous studies| these systems are found to be associated with localized pressure cells whose positions are controlled by topography and coastal geography. (3) Decreases in planetary albedo| occurring because of reductions in sea ice| snow cover| and low clouds| and increases in atmospheric water vapor are the positive climate feedbacks that amplify the global warming. Similar to other Mesozoic climate simulations| our model finds that large seasonal temperature fluctuations occurred over mid- and high-latitude continental interiors| refuting paleoclimate evidence that suggests more equable conditions. Sensitivity experiments suggest that some combination of ocean heat transport increase| high levels of CO2| and improved modeling of ground hydrological schemes may lead to a better match with the geologic record. We speculate| also| that the record itself is biased toward "equable" climatic conditions| a suggestion that may be tested by comparing GCM results with more detailed phytogeographic analyses. 2172,1992,5,3,PAST AND FUTURE CLIMATE CHANGE - RESPONSE BY MIXED DECIDUOUS CONIFEROUS FOREST ECOSYSTEMS IN NORTHERN MICHIGAN,During the 21st century| global climate change is expected to become a significant force redefining global biospheric boundaries and vegetation dynamics. In the northern hardwood - boreal forest transition forests| it should| at the least| control reproductive success and failure among unmanaged mixed forest stands. One means by which to predict future responses by the mixed forests is to examine the way in which they have responded to climate changes in the past. We used proxy climate data derived from Holocene (past 10 000 years) pollen records in the western Upper Peninsula of Michigan to drive forest gap models| in an effort to define regional prehistoric vegetation dynamics on differing soils. The gap models mimic forest reproduction and growth as a successional process and| hence| are appropriate for defining long-term tree and stand dynamics. The modeled period included a mid-postglacial period that was warmer than today's climate. Model failures| made apparent from the exercise| were corrected and the simulations were repeated until the model behaved credibly. Then| the same gap model was used to simulate potential future vegetation dynamics| driven by projections of a future climate that was controlled by greenhouse gases. This provided us with the same "measure" of vegetation in the past| present| and future| generating a continuously comparable record of change and stability in forest composition and density. The resulting projections of vegetation response to climate change appear to be affected more by the rate than by the magnitude of climate change.
3686,1992,2,1,PAST| PRESENT AND FUTURE LEVELS OF GREENHOUSE GASES IN THE ATMOSPHERE AND MODEL PROJECTIONS OF RELATED CLIMATIC CHANGES,Ice core analyses of polar ice reveal a high correlation between climatic change and variations in the atmospheric concentrations of greenhouse gases (carbon dioxide and methane) over the last 160 000 years. Although the resolution of the data is not sufficient to determine the phase relationship between the respective variations| it is generally believed that climate change occurred first as a result of the quasi-periodic variations of the Earth's orbital parameters. However| data and model results are consistent with the hypothesis that climate and atmospheric concentrations of greenhouse gases interact via a positive feedback loop. The more recent increase in greenhouse gases since pre-industrial times can be related to human activities. Climate models predict a significant global warming of several degrees within the next century if the industrial emissions increase unabated. On the other hand| accelerated policies on emission control will significantly reduce the warming after a response time of a few decades. 3724,1992,3,3,POSSIBLE CONTRIBUTION OF CARBON-DIOXIDE FLOODING TO GLOBAL ENVIRONMENTAL-ISSUES,The problem of global warming illustrates the serious interrelationship between the production of energy and environmental concerns. As part of the survey on the effective use of carbon dioxide| taking the global environment into consideration| a study was carried out on the application Of CO2 in EOR as a countermeasure to global warming. This paper studies the feasibility of a total system for the stabilization of CO2 using EOR. This system involves separation and recovery Of CO2 from fixed sources in Japan| liquefaction and transportation to the oil-fields in oil producing countries| injection to the reservoir and eventual recovery and recycling. Utilization of CO2 for EOR therefore| not only increases oil production but also results in the stabilization of CO2| thus preventing further global warming. 3710,1992,5,3,POSSIBLE METHANE-INDUCED POLAR WARMING IN THE EARLY EOCENE,RECONSTRUCTIONS of early Eocene climate depict a world in which the polar environments support mammals and reptiles| deciduous forests| warm oceans and rare frost conditions 1-5. At the same time| tropical sea surface temperatures are interpreted to have been the same as or slightly cooler than present values 6. The question of how to warm polar regions of Earth without noticeably warming the tropics remains unresolved; increased amounts of greenhouse gases would be expected to warm all latitudes equally 7. Oceanic heat transport has been postulated as a mechanism for heating high latitudes 8-10| but it is difficult to explain the dynamics that would achieve this 7|11. Here we consider estimates of Eocene wetland areas and suggest that the flux of methane| an important greenhouse gas| may have been substantially greater during the Eocene than at present. Elevated methane concentrations would have enhanced early Eocene global warming| and also might specifically have prevented severe winter cooling of polar regions because of the potential of atmospheric methane to promote the formation of optically thick| polar stratospheric ice clouds 12-14. 3690,1992,2,4,POTENTIAL CARBON LOSSES FROM PEAT PROFILES - EFFECTS OF TEMPERATURE| DROUGHT CYCLES| AND FIRE,Global warming and the resultant increase in evapotranspiration might lead to lowered water tables in peatlands and an increase in fire frequency. The objective of this study was to investigate some of the potential effects of these changes on peat decomposition. Dry mass losses and emissions of CO2 and CH4 from peat samples taken from three depth layers (0-10| 10-20| and 30-40 cm) of a black spruce peatland were measured in the laboratory at 8-degrees| 16-degrees| and 24-degrees-C under two moisture treatments. Effects of deep peat fire on decomposition were also simulated by burning the upper layer (0-10 cm) of peat and adding the ash to peat samples from the 10-20 cm layer. CH4 release averaged < 1% of total carbon loss in flooded samples. Release of CO2 was 4-9 times greater from the 0-10 cm layer than from the 30-40 cm layer. After 120 d| the 30-40 cm layer had lost < 1% of its original dry mass in all treatments. Higher temperatures strongly promoted decomposition of samples exposed to drying cycles but had little effect on decomposition of continuously flooded samples. Ash addition had variable effects on CO2 emissions but may have promoted CH4 production. It is suggested that in certain situations| global warming may not cause appreciable increases in carbon loss from peat deposits. The results indicate that some deeper peats are resistant to decay even when exposed to warm| aerobic conditions. However| further experimental work is needed to predict the long-term response of peat deposits to changes in water levels in different peatland types. 3766,1992,4,4,POTENTIAL CLIMATE IMPACT OF MOUNT-PINATUBO ERUPTION,We use the GISS global climate model to make a preliminary estimate of Mount Pinatubo's climate impact. Assuming the aerosol optical depth is nearly twice as great as for the 1982 El Chichon eruption| the model forecasts a dramatic but temporary break in recent global warming trends. The simulations indicate that Pinatubo occurred too late in the year to prevent 1991 from becoming one of the warmest years in instrumental records| but intense aerosol cooling is predicted to begin late in 1991 and to maximize late in 1992. The predicted cooling is sufficiently large that by mid 1992 it should even overwhelm global warming associated with an El Nino that appears to be developing| but the El Nino could shift the time of minimum global temperature into 1993. The model predicts a return to record warm levels in the later 1990s. We estimate the effect of the predicted global cooling on such practical matters as the severity of the coming Soviet winter and the dates of cherry blossoming next spring| and discuss caveats which must accompany these preliminary simulations. 2183,1992,2,3,POTENTIAL EFFECTS OF GLOBAL CLIMATE CHANGE ON THE BIODIVERSITY OF PLANTS,Climatologists have observed a consistent increase in atmospheric CO2 over the past 30 years. It is predicted that CO2 levels could double the pre-industrial level of 280 ppm by the year 2100| perphaps much earlier. Climate models of doubled atmospheric CO2 predict that mean temperatures will increase between 1.5 and 4.5-degrees-C globally; these temperature changes will be greater at high latitudes. Mid-continental regions will experience lower rainfall. Predictions of species northward range shifts in response to climate change vary from 100 km to over 500 km. Historical evidence of species range movements following the Pleistocene indicate that tree species typically migrated at rates of 10 km to 40 km per century. A simulation model that predicts the migration response of trees through modem fragmented landscapes predicts migration rates much lower than Pleistocene observations. Thus migration response is likely to lag far behind rates of climatic change| potentially threatening narrowly distributed species whose predicted future ranges do not overlap with their current range. Insect pests and microbial pathogens should respond to climatic warming faster than long-lived trees. Predicted increased drought frequency may increase plant stress and thereby increase the frequency of insect outbreaks and disease. Predictions of species responses are complicated by direct effects of increased CO2| such as increased water-use. efficiency. However| response to elevated CO2 vanes among species. Thus| shifts in composition within plant communities are also likely| but are| as yet| unpredictable.
3694,1992,2,3,POTENTIAL EFFECTS OF THE INCREASE IN CARBON-DIOXIDE AND CLIMATE CHANGE ON THE DYNAMICS OF VEGETATION,The continued CO2 loading of the atmosphere appears to be responsible for inducing three new force factors controlling dynamic changes in the world's vegetation. They come from (1) enhanced fertilization with the single most important plant nutrient| (2) the widely expected global temperature increase| and (3) aggravated weather disturbances. Increased CO2 absorption may enhance plant growth but it may also increase soil-nutrient limitations. It surely will enhance the metabolism of forest trees similarly as global warming will enhance plant metabolism| but both factors may also shorten the lifespan of perennial plants. Increased weather disturbances can be expected to produce new physiological stresses on the standing vegetation| particularly on habitats with poor soils. Since wide-spread forest decline has been reported from both the Atlantic and Pacific region| it seems possible that the roughly synchronic mass mortality of trees during the past two decades is related to the global increase in CO2. The paper gives an overview of forest decline and dieback as known from past and present research and suggests how the changing atmospheric environment may interact in this widely observed contemporary Phenomenon of vegetation dynamics. 3757,1992,2,4,POTENTIAL RESPONSE OF AN ARCTIC WATERSHED DURING A PERIOD OF GLOBAL WARMING,Climatic warming presents an imposing problem to scientists everywhere. Its effect in the Arctic is accentuated for several reasons. The temperature increase is expected to be greatest in the higher latitudes and the ramifications of this warming may be more crucial there due to the melting of permafrost. Precipitation changes will likely accompany climatic warming in the Arctic| compounding the effect of a temperature increase. The interaction of changing hydrologic and thermal processes presents a complex problem which would be difficult if not impossible to analyze without the use of detailed computer modeling. To analyze the thermal impact of climatic warming on a permafrost environment| TDHC| a heat conduction model which incorporates phase change| was used. Then the response of the active layer to climatic warming was incorporated into HBV| a hydrologic model| to elucidate the effects on the hydrologic regime. Several scenarios of climatic warming have been examined to determine the impact on the active layer depth| but only results of 4-degrees-C warming at a typical arctic site will be presented here. In the case of 4-degrees-C warming| three scenarios of precipitation were studied: no change| + 15%| and -15%. The most obvious and perhaps significant response to climatic warming was an increase in active layer depth. Other changes worth noting were warming of the entire soil profile| increased soil moisture storage| increased evaporation| and variable response in runoff| depending upon the scenario. Evaporation now vies with runoff as the primary loss of moisture from the watershed. If evaporation increases due to a warmer climate| the entire character of arctic hydrology could change| depending on changes in precipitation. 3655,1992,2,4,PREDICTING EFFECTS OF GLOBAL WARMING ON GROWTH AND MORTALITY OF UPLAND OAK SPECIES IN THE MIDWESTERN UNITED-STATES - A PHYSIOLOGICALLY BASED DENDROECOLOGICAL APPROACH,This study combined an ecophysiological model and dendroecological analyses to evaluate potential effects of global warming on the physiology| growth| and mortality of white oak (Quercus alba L.) and black oak (Quercus velutina Lam.) in the Ohio River region. The model integrated data for ecophysiology of oak species| site attributes| and daily temperature and precipitation to model nonlinear responses of stomatal conductance (g(s))| net photosynthesis (P(net))| and woody respiration (R(w)) to variations in temperature and soil water content. Relationships between modeled physiological response indices and actual white and black oak annual radial growth indices were evaluated by regression analyses| using growth and weather data for the period 1900-1987 for seven upland oak hickory forests. Modeled physiological response indices explained 40-60% of variation in radial growth indices. To evaluate the effects of global warming| daily temperature values for the period 1900-1987 were increased by 2 or 5-degrees-C| without changing precipitation values| and physiological response indices were computed. Model indices generated in warming simulations were entered into dendroclimatic regression models calibrated under conditions without any warming to predict radial growth under warming scenarios. Under the warming scenarios| OAKWBAL predicted a substantial increase in growing season R(w)| but little change in growing season P(net). Warming merely shifted the period of near-maximal P(net)| earlier in the growing season| without changing its duration. However| this result was somewhat dependent upon the ability of leaf-out phenology to track changes in temperature regime. The net effect of increased R(w)| with little change in P(net)| was a reduction in radial growth and a higher frequency of years with climatic conditions stressful to oaks on upland sites. A historical association between severe drought and increased incidence of oak growth decline and mortality indicated that global warming could increase the incidence of decline and mortality in oak populations on upland sites similar to those in this study. 3698,1992,2,3,PREDICTING THE IMPACTS OF GLOBAL WARMING ON WILDLAND FIRE,Simulations of impacts of a double-CO2 climate with the Changed Climate Fire Modeling System in Northern California consistently projected increases in area burned and in the frequency of escaped fires compared with simulations of the present climate. However| the magnitude of those increases was strongly influenced by vegetation type| choice of atmospheric general circulation model (GCM) scenario| and choice of climate forcing variables. The greatest projected increase in fire severity occurred in grasslands| using the Princeton Geophysical Fluid Dynamics Laboratory GCM| with wind speed| temperature| humidity and precipitation as driving variables. 2190,1992,4,4,PRIORITIZING ECOLOGICAL AND HUMAN-WELFARE RISKS FROM ENVIRONMENTAL STRESSES,The ecological systems of Earth are subjected to a wide array of environmental stresses resulting from human activities. The development of appropriate environmental protection and management policies and the appropriate allocation of resources across environmental stresses require a systematic evaluation of relative risks. The data and methodologies for comprehensive ecological risk assessment do not exist| yet we do have considerable understanding of ecological stress-response relationships. A methodology is presented to utilize present knowledge for assignment of relative risks to ecological systems and human welfare from anthropogenic stresses. The resultant priorities| developed for the US Environmental Protection Agency's (EPA) relative risk reduction project| highlight global climate change| habitat alteration| stratospheric ozone depletion| and species depletion as the highest environmental risks| significantly diverging from the present emphasis by EPA and the public on toxic chemical issues. Enhanced attention to ecological issues by EPA and development of ecological risk assessment methodologies that value ecological and economic issues equitably are key recommendations.
3776,1992,3,4,PRODUCTION OF NITROUS-OXIDE GAS DURING DENITRIFICATION OF WASTE-WATER,Laboratory-scale experiments were conducted to examine nitrous oxide (N2O) production during denitrification. Substrate containing acetate (909 mgl-1 as COD)| yeast extract (91 mgl-1 as COD) and KNO3 with COD/NO3-N of 1.5| 2.5| 3.5 and 4.5 was continuously fed to 3 1 mixed flow reactors with varied solid retention time (SRT). N2O in produced nitrogenous gas far exceeded 10% in some conditions| and up to 8% of influent NO3-N was transformed to N2O. Low COD/NO3-N| short SRT and low pH were favored conditions for N2O production. COD/NO3-N of 1.5 and 2.5 at an SRT shorter than 10 days| and COD/NO3-N of 3.5 or 4.5 at an SRT shorter than 1 day resulted in N2O production together with incomplete nitrate and nitrite removal. Lower COD/NO3-N caused higher production of N2O. N2O Production at pH of 6.5 was significantly higher than that at pH of 7.5| although pH of 7.5 and 8.5 showed less difference. The mixed liquor from the continuous reactor producing N2O readily produced N2O even when substrate with high COD/NO3-N was dosed in batch experiments| which suggests that N2O producing species may be accumulated during continuous operation in favorable conditions. 3762,1992,4,3,RADIATIVE FORCING AND GREENHOUSE-EFFECT DUE TO THE ATMOSPHERIC TRACE GASES,The radiative forcing and greenhouse effect due to the atmospheric trace gases have been calculated by using an advanced radiative-convective model developed in this paper. The relationship between radiative forcing and concentration is given for each trace gas. The results show that (i) the radiative forcing and then the greenhouse effect are significantly affected by the overlapping of atmospheric absorption bands; (ii) the increasing concentration of trace gases other than CO2| such as CH4| N2O| CFCs| etc.| may potentially play an important role in the future global warming; (iii) the proposed substitutes| such as HCFC124 and HFC125| for the chlorofluorocarbons which are considered to destroy the ozone layer have still considerable greenhouse effect even though their ozone depletion potentials are much smaller than CFCs; and (iv) the feedback processes within the earth-atmosphere system have important effect on the surface temperature change due to the radiative forcing to the system. 3782,1992,4,4,RARE AND ENDANGERED SPHAGNUM SPECIES IN NORTH-AMERICA,Thirty taxa of Sphagnum are considered rare (R)| vulnerable (V) or endangered (E) in North America| the lower 48 United States| Canada or Alaska. Six species are classified endangered or vulnerable at a global level. Maps indicating the known distribution of 18 taxa are presented. The percentage of Sphagnum taxa considered R| V or E seems lower than that for bryophytes in general. Sphagnum species should be protected because of their potential value as indicators of global warming and atmospheric pollution. 3695,1992,3,3,REALISTIC MITIGATION OPTIONS FOR GLOBAL WARMING,Policy responses to global climate change have been hampered by large uncertainties in the magnitude and timing of potential impact and the economic implications of proposed response measures. Cost-effectiveness is a key measure for comparing a broad range of options to mitigate the effects of greenhouse warming. Although the full cost of many mitigation measures is difficult to assess| analysis suggests that a variety of energy efficiency and other measures that are now available could reduce U.S. emissions of greenhouse gases by roughly 10 to 40% of current levels at relatively low cost perhaps at a net cost savings. Such measures are proposed as an initial U.S. response to global warming concerns in conjunction with other domestic and international efforts.
2205,1992,4,3,RECENT DEVELOPMENTS IN SCIENTIFIC KNOWLEDGE ON CLIMATE CHANGE,Since industrial times| human activities caused a substantial concentration increase of carbon dioxide and some additional climate-relevant trace gases in the atmosphere. There is no doubt that this process leads to global climate change| although the quantitative and regional patterns of this change are not exactly known. Moreover| this process is in competition with natural 'climate fluctuations. This brief paper summarizes the climate model projections of anthropogenic climate change (enhanced 'greenhouse effect') and discusses some aspects of observational climatic data. 2179,1992,4,4,REGIONAL CLIMATES IN THE GISS GLOBAL CIRCULATION MODEL - SYNOPTIC-SCALE CIRCULATION,Model simulations of global climate change are seen as an essential component of any program aimed at understanding human impact on the global environment. A major weakness of current general circulation models (GCMs)| however| is their perceived inability to predict reliably the regional consequences of a global-scale change| and it is these regional-scale predictions that are necessary for studies of human-environmental response. For large areas of the extratropics| the local climate is controlled by the synoptic-scale atmospheric circulation| and it is the purpose of this paper to evaluate the synoptic-scale circulation of the Goddard Institute for Space Studies (GISS) GCM. A methodology for validating the daily synoptic circulation using Principal Component Analysis (PCA) is described| and the methodology is then applied to the GCM simulation of sea level pressure over the continental United States (excluding Alaska). The analysis demonstrates that the GISS 4-degrees X 5-degrees GCM Model II effectively simulates the synoptic-scale atmospheric circulation over the United States. The modes of variance describing the atmospheric circulation of the model are comparable to those found in the observed data| and these modes explain similar amounts of variance in their respective datasets. The temporal behavior of these circulation modes in the synoptic time frame are also comparable.
3773,1992,5,4,RELATIVE SEA-LEVEL RISE AND CLIMATE CHANGE OVER THE LAST 1500 YEARS,We constructed a detailed relative sea-level rise curve for the last 1500 years using a novel approach| i.e. charting the rate of relative sea-level rise using microfaunal and geochemical data from a coastal salt marsh sequence (Clinton| CT| USA). The composition of benthic foraminiferal assemblages and the iron abundance in peats were used to describe shifts in marsh environment through time quantitatively. The resulting sea-level rise curve| with age control from C-14 dating and the onset of anthropogenic metal pollution| shows strong increases in the rate of relative sea-level rise during modem global warming (since the late nineteenth century)| but not during the Little Climate Optimum (AD 1000-1300). There was virtually no rise in sea-level during the Little Ice Age (AD 1400-1700). Most of the relative sea-level rise over the last 1200 years in Clinton appears to have occurred during two warm episodes that jointly lasted less than 600 years. Changes from slow to fast rates of relative sea-level rise apparently occurred over periods of only a few decades. We suggest that changes in ocean circulation could contribute to the sudden increases in the rate of relative sea-level rise along the northeastern USA seaboard. Relative sea-level rise in that area is currently faster than the worldwide average| which may result partially from an ocean surface effect caused by hydrodynamics. Our data show no unequivocal correlation between warm periods (on a decaal to centennial time-scale) and accelerated sea-level rise. One period of acclerated sea-level rise may have occurred between about AD 1200 and 1450| which was the transition for the Little Climate Optimum to the Little Ice Age| i.e. a period of cooling (at least in northwestern Europe). Local changes in tidal range might also have contributed to this apparent increase in the rate of relative sea-level| however. The second period of accelerated sea-level rise occurred during the period of modem global warming that started at the end of the last century. 3739,1992,2,4,RESPONDING TO POTENTIAL IMPACTS OF CLIMATE CHANGE ON UNITED-STATES COASTAL BIODIVERSITY,Accelerated rates of sea level rise and other impacts of climate change resulting from global warming are likely to aggravate threats to coastal biodiversity in the United States. Species restricted to or dependent upon a narrow band of habitat close to sea level will be subjected to continuing threats of development from above| and rising sea levels from below. In five states alone| almost 500 rare and imperiled species utilize the coastal fringe below the 10-foot contour. Some 53 species federally listed as threatened or endangered or as candidates for listing are found only within the narrow band below the 10-foot contour. Rising seas will stress coastal habitats including wetlands| barrier islands| coral reefs| and mangroves| in some cases substantially reducing their area. To ensure the conservation of coastal biodiversity global warming must be slowed as much as possible. Steps must also be taken quickly to establish coastal zone policies that allow adaptive response to rising seas by making way for the shoreward movement of coastal ecosystems as sea level changes. 2199,1992,2,4,RESPONSE OF ALLUVIAL SYSTEMS TO FIRE AND CLIMATE CHANGE IN YELLOWSTONE-NATIONAL-PARK,PROJECTIONS of the ecological effects of global climate change often include increased frequency and/or intensity of forest fires in regions of warmer and drier climate 1-3. In addition to disturbing biological systems| widespread intense fires may influence the evolution of the physical landscape through greatly enhanced sediment transport 4. Debris-flow to flood-streamflow sedimentation events following the 1988 fires in the Yellowstone National Park area (Wyoming and Montana| USA) have allowed us to examine the geomorphological response to fire in a mountain environment. Abundant analogous deposits in older alluvial fan sequences bear witness to past fire-related sedimentation events in northwestern Yellowstone| and radiocarbon dating of these events yields a detailed chronology of fire-related sedimentation for the past 3|500 years. We find that alluvial fans aggrade during periods of frequent fire-related sedimentation events| and we interpret these periods as subject to drought or high climatic variability. During wetter periods| sediment is removed from alluvial fan storage and transported down axial streams| resulting in floodplain aggradation. The dominant alluvial activity is strongly modulated by climate| with fire acting as a drought-actuated catalyst for sediment transport.
2214,1992,2,4,SEED AND SEEDLING BIOLOGY IN RELATION TO MODELING VEGETATION DYNAMICS UNDER GLOBAL CLIMATE CHANGE,The distribution of many plant species will change with global climate change| depending on their ability to disperse into| and establish in| new communities. Past migrations of species under climate change have been an order of magnitude slower than the rate of predicted climate change for the next century. The limited evidence available suggests that chance long distance dispersal events will be critically important in determining migration rates. We examine the JABOWA-derived gap replacement models and vital attributes/FATE models and ask: what do we need to know about dispersal and establishment to make improved projections of vegetation dynamics under climate change using these models? The minimal modifications of these models required to incorporate directional migration of species are described. To predict establishment success of species| we suggest that a more fundamental understanding is needed of how establishment ability under different conditions relates to seed and seedling attributes and how this may be affected by elevated CO2. Finally| we examine whether plant functional types based on vegetative attributes (used to model the response of adult plants) are correlated with functional types based on seed and seedling attributes. Available evidence suggests that the two sets of attributes are not strongly correlated; consequently| models of vegetation dynamics will need to incorporate seed biology explicitly.
3669,1992,2,3,SENSITIVITY OF PACIFIC-NORTHWEST WATER-RESOURCES TO GLOBAL WARMING,The potential effect of increasing atmospheric concentrations of carbon dioxide and other so-called greenhouse gases on the land surface environment is not well understood. Generally| there is some consistency among computer models of global climate that surface temperatures will increase and that| in many areas| precipitation and evaporation also may increase. However| determining the effects of such changes on the distribution and circulation of water at the land surface| and on water management systems| remains problematic. The American River| Washington| a mountainous tributary of the Yakima River| is typical of rivers in the Columbia Basin states of Washington| Oregon| Idaho| and western Montana| as well as southern British Columbia. Using the American River as a case study| this investigation developed computer models to simulate and identify water management conflicts that might arise in this region under a general climate warming of both 2-degrees-C and 4-degrees-C. For warmer climates| it was found that snow accumulation would be substantially reduced| and the river's high flow season would shift from the spring to the winter. Potential evaporation would increase throughout the year (mostly in the summer)| but peak actual evaporation would shift to the late spring and early summer| due to reduced summer soil moisture. The effect of the streamflow pattern that would accompany a warmer climate was tested on small and moderate sized hypothetical multi-purpose reservoirs. The results showed that water supply reliability would be significantly degraded by the earlier spring runoff pattern that would accompany a warmer climate| especially for small reservoirs. The result was that hydroelectric revenues might increase due to larger reservoir releases needed during the winter peak demand season. An investigation of alternative operating policies for the reservoir system showed that more efficient reservoir operation alone would not mitigate the degraded reliability of water supply that would accompany a warmer climate. 3746,1992,2,4,SEX-RATIO OF HATCHLING LOGGERHEAD SEA-TURTLES - DATA AND ESTIMATES FROM A 5-YEAR STUDY,Hatchling loggerhead sea turtles (Caretta caretta) were collected over three nesting seasons from a rookery at Cape Canaveral| Florida. From data on the distribution of nests over the season| we estimated that 92.6-96.7| 94.7-99.9| and 87.0-89.0 % of the hatchlings produced on this beach in 1986| 1987| and 1988| respectively| were females. These skewed sex ratios were consistent with the fact that for most of the season| sand temperatures were above the pivotal level for loggerhead turtles. The present results show that the female-biased sex ratio reported previously by these authors for the 1986 nesting season at this site was not an isolated| atypical event. In addition to a total of 3 years of sampling for sex ratio| measurements of beach temperatures at the depth of turtle nests were extended to cover 5 years. These temperatures were commonly above the pivotal level. The strongly female-biased hatchling sex ratio found in this population of loggerhead turtles poses theoretical challenges. It may also complicate conservation efforts| since global warming might be expected to skew the sex ratio still further toward females. 2184,1992,3,3,SHOULD WE STORE CARBON IN TREES,In order to explore for the most effective strategy for using forests to mitigate global climate change| we have constructed a simple model of C uptake during forest growth and the fate of this C when forests are harvested and used as fuel to replace fossil fuels. We suggest that trees are equally effective in preventing the accumulation of CO2 in the atmosphere if they remove a unit of C from the atmosphere or if they supply a sustainable source of energy that substitutes for a unit of C discharged by burning fossil fuels. The model shows that the most effective strategy for using forest land to minimize increases in atmospheric CO2 will depend on the current status of the land| the productivity that can be expected| the efficiency with which the forest harvest is used to substitute for fossil fuels| and thc time perspective of the analysis. For forests with large standing biomass and low productivity the most effective strategy is to protect the existing forest. For land with little standing biomass and low productivity| the most effective strategy is to reforest or otherwise manage the land for forest growth and C storage. Where high productivity can bc expected| thc most effective strategy is to manage the forest for a harvestable crop and to use the harvest with maximum efficiency either for long-lived products or to substitute for fossil fuels. The longer the time perspective| the more likely that harvesting and replanting will result in net C benefits.
2210,1992,4,4,SIBLING SPECIES IN MONTASTRAEA-ANNULARIS| CORAL BLEACHING| AND THE CORAL CLIMATE RECORD,Measures of growth and skeletal isotopic ratios in the Caribbean coral Montastraea annularis are fundamental to many studies of paleoceanography| environmental degradation| and global climate change. This taxon is shown to consist of at least three sibling species in shallow waters. The two most commonly studied of these show highly significant differences in growth rate and oxygen isotopic ratios| parameters routinely used to estimate past climatic conditions; unusual coloration in the third may have confused research on coral bleaching. Interpretation or comparison of past and current studies can be jeopardized by ignoring these species boundaries.
3666,1992,4,4,SINGULAR-SPECTRUM ANALYSIS - A TOOLKIT FOR SHORT| NOISY CHAOTIC SIGNALS,Singular-spectrum analysis (SSA) is developed further| based on experience with applications to geophysical time series. It is shown that SSA provides a crude but robust approximation of strange attractors by tori| in the presence of noise. The method works well for short| noisy time series. The lagged-covariance matrix of the processes studied is the basis of SSA. We select subsets of eigenelements and associated principal components (PCs) in order to provide (i) a noise-reduction algorithm| (ii) a detrending algorithm| and (iii) an algorithm for the identification of oscillatory components. Reconstructed components (RCs) are developed to provide optimal reconstruction of a dynamic process at precise epochs| rather than averaged over the window length of the analysis. SSA is combined with advanced spectral-analysis methods - the maximum entropy method (MEM) and the multi-taper method (MTM) - to refine the interpretation of oscillatory behavior. A combined SSA-MEM method is also used for the prediction of selected subsets of RCs. The entire toolkit is validated against a set of four prescribed time series generated by known processes| quasi-periodic or chaotic. It is also applied to a time series of global surface air temperatures| 130 years long| which has attracted considerable attention in the context of the global warming issue and provides a severe test for noise reduction and prediction. 2192,1992,4,4,SOME REMARKS ON THE SCIENTIFIC PROBLEMS RELATED TO THE GREENHOUSE GAS ISSUE,Some of the fundamental problems related to the current approach to global climate change from modelling and observational stand points are discussed. The author offers his personal opinion and suggests caution in terms of an all out effort to understand the problem through numerical modelling based on GCMs models. At the same time he advises other approaches i.e. statistical and other studies of atmospheric phenomena different from temperature in seeking evidences of climate change. He emphazises in particular the need to find| for political reasons and as soon as possible| a clear signal that the greenhouse gas affect is being enhanced and that this has an impact on the general circulation of the atmosphere.
3732,1992,3,3,STABILIZING CO2 EMISSIONS - ARE CARBON TAXES A VIABLE OPTION,The paper provides an empirical analysis of the effect on international energy markets of policy measures to curb the emissions of carbon dioxide (CO2). Model calculations indicate that if CO2 emissions are to be stabilized by means of a carbon tax| very high tax levels are required. The concept of cost-effectiveness in designing a global climate convention is discussed. Due to the huge differences in pre-tax energy prices| it is argued that a uniform CO2 tax is not necessarily cost-effective. The differences in price levels also have important implications for the effects of a CO2 tax on the markets for the various fuels. 2169,1992,3,4,STRATEGIES FOR ADDRESSING CLIMATE CHANGE - POLICY PERSPECTIVES FROM AROUND THE WORLD,The greenhouse effect is intrinsically global. Accordingly| effective responses require global coordination. While limited policies have been adopted| notably for phasing out chlorofluorocarbons| there is no clear consensus as to what to do about other greenhouse gases. In this paper| we survey attitudes and policy responses among the nations of the world. Public opinion surveys are consistent in showing that considerable sensitivity to environmental issues exists virtually everywhere. On the other hand| there is acute awareness that other issues| especially economic development| can conflict with global climate-change mitigation goals. In such a state of uncertainty there is a strong argument to be made for implementing policies which are good ideas independent of greenhouse-gas considerations. There is also good reason to expand research. What is feasible depends strongly on present and changing attitudes of the citizens of the world| and of their governments. It is thus critical to follow closely the evolution of attitudes. The kind of work summarized in this paper needs to be updated on a continuing basis| and the results made available routinely to the global policy community. We conclude our review with several recommendations for research designed specifically to reduce uncertainty about costs and institutional issues relating to responses to global climate change.
3744,1992,3,3,STRENGTHENING THE MONTREAL PROTOCOL - DOES IT COOL DOWN THE GREENHOUSE,Strengthening of the Montreal Protocol is recently being negotiated in London in 1990 in order to achieve further reductions of the regulated CFCs and to include possibly more substances. In this article the implications of different policies with respect to control of ozone depleting substances for climate change are analysed| including the proposed substitution by HCFCs and HFCs| carbon tetrachloride and methylchloroform. A special halocarbon module was developed within the framework of RIVM's Integrated Model to Assess the Greenhouse Effect (IMAGE). IMAGE is a parameterized science based policy model and has been developed to give policy agencies a concise overview of the quantitative aspects of the greenhouse problem| to evaluate various policy options concerning climate change and to serve as a means of communication. It is concluded| from simulations with the halocarbon module| that it is of primary importance to achieve a further reduction of the regulated CFCs compared to the Montreal Protocol with compliance by as many countries as possible. From the perspective of the greenhouse effect the inclusion of longer lived halocarbons| such as carbon tetrachloride and HCFC-22 in the protocol comes second. The application of methylchloroform| halons and HCFCs and HFCs with lower global warming potentials (GWPs) than HCFC-22 contributes only marginally to the greenhouse effect in comparison with the much more important greenhouse gases carbon dioxide| methane| ozone and nitrous oxide. Especially if further growth of the total production of HCFCs after complete replacement of the present CFCs can be avoided by using these alternatives with a lower GWP| these substances could therefore be tolerated in a transition period| from the perspective of global warming. 3714,1992,3,4,SYSTEM STUDIES ON CO2 ABATEMENT FROM POWER-PLANTS,British Coal Corporation is taking a proactive stance in researching the issues associated with the possibility of enhanced global warming. One aspect of this research is the evaluation of the options which might conceivably be required if it tums out to be necessary to reduce CO2 emissions from coal fired power plants more than can be achieved by improved efficiency. A programme of assessment studies has been undertaken to evaluate the impacts on plant thermal efficiency of various options for CO2 removal for ultimate storage in some form of long term repository. Preliminary screening studies of the integration of CO2 recovery into coal fired power generation processes have indicated that routes based on Integrated Gasification Combined Cycles (IGCC) are preferred to those based on combustion. A series of options based on IGCC with CO shift is presented which compares alternative means of separating hydrogen from CO2| as required by this process route. Technologies evaluated include chemical and physical solvent scrubbing and membrane separation. This work was carried out with the intention of identifying thermally efficient flowsheets and the associated process development needs. The paper concludes by presenting economic considerations and describing British Coal's future research programme in this area. 3633,1992,4,4,TEMPERATURE AND SIZE VARIABILITIES OF THE WESTERN PACIFIC WARM POOL,Variabilities in sea-surface temperature and size of the Western Pacific Warm Pool were 1982 to 1991. The results show that both annual mean sea-surface temperature and the size of the warm pool increased from 1983 to 1987 and fluctuated after 1987. Possible causes of these variations include solar irradiance variabilities| El Nino-Southern Oscillation events| volcanic activities| and global warming. 3713,1992,2,4,TEMPERATURE EFFECTS ON SEEDLING EMERGENCE FROM BOREAL WETLAND SOILS - IMPLICATIONS FOR CLIMATE CHANGE,Temperature treatments simulated global warming effects on seedling emergence of wetland species from soil seed banks of the Peace-Athabasca Delta| Alberta. Canada. Introduced weedy species. such as Tanacetum vulgare L.| bad up to a 10-fold greater emergence at high temperature (30-degrees-C for 18 h with light. 15-degrees-C for 6 h in the dark) than at low temperature (20/10-degrees-C). Seedling emergence of native weedy species| such as Calamagrostis canadensis (Michx.) Beauv.| was 1.5-3 times greater at low temperature. Other native weedy species. such as Rubus idaeus L.| emerged only from samples at low temperature. Emergence of native non-weedy species was greatest at high temperature| even though mature plants of species such as Ranunculus hyperboreus Rottb. and Carex eburnea Boott are normally found in cool and moist habitats. Of those species expected to persist in warm and dry habitats. only introduced weedy species showed consistent and significantly greater seedling emergence at high temperature. It is hypothesized| therefore. that the abundance of introduced weedy species would increase in disturbed or sparsely vegetated zones around water bodies as these zones become dry and warm with climate change. 3640,1992,2,4,THE ADAPTIVE SIGNIFICANCE OF SEASONAL REPRODUCTION IN MARINE-INVERTEBRATES - THE IMPORTANCE OF DISTINGUISHING BETWEEN MODELS,Seasonal reproduction is a dominant characteristic of the reproduction of major groups of marine invertebrates. The seasonality may be extreme culminating in very synchronised mass spawning events. Hypotheses to explain strongly seasonal reproduction are appraised in relation to demographic theory of life history which supposes that a limited resource (e.g.| energy) may be allocated to (a) maintenance and defense against the environment (respiration| excretion| ionic regulation| etc.); (b) growth; or (c) propagule production and present reproduction. Allocation to each contributes to fitness through demographic components that can be defined by the Euler-Lotka equation. Hypotheses to account for strongly seasonal reproduction must explain the mechanism that confers selective advantage to highly seasonal non-random deployment of limited resources to reproduction. The various hypotheses proposed can be classified as (I) non-functional and (II) functional. Functional hypotheses suppose that a selective advantage accrues as a consequence of energy storage prior to allocation to reproductive function. There are costs associated with this energy storage that must be compensated by the selective advantage accruing from delayed deployment of resources. A number of different functional hypotheses can be identified which may be allocated to two sets of related hypotheses: (A) Synchronisation maximises offspring survival - the optimum larval survival strategy; and (B) Synchronisation maximises fitness independently of offspring survival - the optimum fertilisation strategy. Several versions of each can be identified; their predictions are examined and discussed in relation to possible consequences of enhanced rates of environmental change (global warming). 3790,1992,3,4,THE BARRIERS TO TECHNOLOGICAL-CHANGE - THE CASE OF TRANSPORTATION,This paper formed the basis of a presentation at the IEA International Conference on 'Technology Responses to Global Environmental Challenges' in Kyoto| Japan 6-8 November 1991. It will examine the status of technology in the transportation sector and the penetration of that technology in both the industrialized and developing countries. The barriers and constraints to technological progress and the wider dissemination of existing technology may be grouped under five headings: The high priority given to mobility by all peoples - it is seen as the most important attribute of economic progress after achieving adequate provision for food arid shelter. The structure of urbanization in the 20th century - which has been based largely on an assumption of personal mobility and/or the availability of transportation infrastructure: roads| public transport| etc. The rapid growth in demand for leisure as a consequence of: (a) the increase in the non-working population of the industrialized countries as life expectancy has increased; (b) the reduction in both retirement age and working hours as technology advances have allowed more goods and services to be provided with substantially lower labour inputs. The desire for greater personal comfort and independence as economic circumstances improve. Institutional barriers to the transfer of technology. These problem areas will be reviewed and some general proposals put forward for enhancing the transfer of technology and resolving some of the sociopolitical issues. 3727,1992,3,3,THE BRITISH COAL GLOBAL WARMING RESEARCH-AND-DEVELOPMENT PROGRAM,The threat of possible global warming is sufficient to warrant 'least regrets' measures to reduce emissions of greenhouse gases and investigation of fallback options| such as carbon dioxide removal from coal-fired power plants. The Global Warming R&D Programme is investigating carbon dioxide removal options| sometimes called 'Low CO2 Power Generation'. An assessment programme has estimated the thermal efficiency of a number of process schemes and concluded that gasification based systems| with the addition of a CO shift reactor and CO2 scrubbers or a membrane gas separator| provide promising approaches. A clean hydrogen fuel would be fired in a gas turbine and 90% of the CO2 removed and exported as a liquid stream for storage in exhausted oil or gas fields. Costs of such power plants are now being explored and a collaborative programme is commencing with membrane developers| with the aim of developing and testing membranes for this duty. The paper outlines the background and describes preparation for experimental work using CO2/H2 separating membranes. 3748,1992,2,4,THE DROUGHT OF 1988| THE GLOBAL WARMING EXPERIMENT| AND ITS CHALLENGE TO IRRIGATION IN THE OLD DUST BOWL REGION,The Great Drought of 1988 was most severe on the northernplains inthe Dakotasand Montana.Droughtwas less severe in the old Dust Bowl heartland of southwest Kansas and the Oklahoma- Texas panhandle. As the summer progressed| however| the awful combi- nation of sun| wind| and lackof rainonce again began to hammer the Dust Bowl.This region was best prepared to protect itself from lack of rain.Not only had lessons been learned the hard way from the 1930s| but local farmers| suppliers| bankers and extension agents had additionally been tested by the droughts of the 1950s and 1970s.1Calledthe "FilthyFifties|" the 1950s drought did not last as long as the one in the 1930s| but it was often as severe. Almost 21 million acres had been seriously damaged and remained vulnerable to more harm. Resettlement and reversion to grass- land no longer were acceptable alternatives. This left the search for more water as the only answer| and points of irrigationfrom groundwater were beginning to appear. Even after it rained in May 1955| and farmers could expect a good crop| 16 million acres were still ready to blow. The mid- 1970s would again bring severe drought. Orbitingearth satellite scanning in the late winter of 1977 clearly showed newly-seeded west Texas farms blowing dust into Oklahoma| while neighboring New Mexico grassland held steady.2 But now| geographer John Borchertcould write that there is "a widespread belief that| though there will be future droughts| there need be no future dust bowl."3 Most important| the south-central High Plains now enjoyed their climate substitute: widespread irrigation from large groundwater supplies.
3772,1992,2,4,THE EFFECT OF TEMPERATURE ON LARVAL FISHES,The influence of temperature on fish eggs and larvae is briefly described from an autecological viewpoint. Temperature may have lethal or sub-lethal effects as well as pacing metabolism| other physiological responses and behaviour. It influences body size| growth| differentiation of muscle and meristic characters. Increase of temperature| as would occur with global warming| will change the timing of ecological events such as the spring plankton outburst so influencing the match or mismatch of larvae with their food supply and their predators. 3701,1992,2,4,THE EFFECTS OF CHEMICAL PROPULSION ON THE ENVIRONMENT,This paper seeks to quantify the effects of chemical propulsion exhaust on both the local launch site and the global environments. Four major areas of concern are discussed: the stratospheric ozone| acid rain| toxicity| and the greenhouse effect. The environmental impacts of both solid and liquid rocket propulsion systems are evaluated. The exhaust species and launch profile of the Space Shuttle| which injects the greatest mass of exhaust products into the atmosphere of any current system| are discussed in some detail. Model calculations predict a global stratospheric ozone reduction of about 0.01% due to chemical propulsion. Acid rain due to the HCl in solid rocket exhaust has a small measurable impact on the local environment| with the mortalities of some plants and small fish very near (<2500 ft) the launch site having been documented. Based on history| the handling of potentially toxic species from the use of chemical propulsion systems is manageable. The relative contribution of chemical propulsion to the global CO2 burden| the increase of which may lead to global warming| is insignificant. It appears that the perturbation to the natural environment caused by chemical propulsion exhaust is very small and manageable| even for the most optimistic projections of future launch rates. 3738,1992,2,4,THE GLOBAL CARBON-DIOXIDE FLUX IN SOIL RESPIRATION AND ITS RELATIONSHIP TO VEGETATION AND CLIMATE,We review measured rates of soil respiration from terrestrial and wetland ecosystems to define the annual global CO2 flux from soils| to identify uncertainties in the global flux estimate| and to investigate the influences of temperature| precipitation| and vegetation on soil respiration rates. The annual global CO2 flux from soils is estimated to average (+/- S.D.) 68 +/- 4 PgC/yr| based on extrapolations from biome land areas. Relatively few measurements of soil respiration exist from arid| semi-arid| and tropical regions; these regions should be priorities for additional research. On a global scale| soil respiration rates are positively correlated with mean annual air temperatures and mean annual precipitation. There is a close correlation between mean annual net primary productivity (NPP) of different vegetation biomes and their mean annual soil respiration rates. with soil respiration averaging 24% higher than mean annual NPP. This difference represents a minimum estimate of the contribution of root respiration to the total soil CO2 efflux. Estimates of soil C turnover rates range from 500 years in tundra and peaty wetlands to 10 years in tropical savannas. We also evaluate the potential impacts of human activities on soil respiration rates| with particular focus on land use changes| soil fertilization| irrigation and drainage| and climate changes. The impacts of human activities on soil respiration rates are poorly documented| and vary among sites. Of particular importance are potential changes in temperatures and precipitation. Based on a review of in situ measurements| the Q10 value for total soil respiration has a median value of 2.4. Increased soil respiration with global warming is likely to provide a positive feedback to the greenhouse effect. 3664,1992,4,4,THE GLOBAL PRODUCTION OF METHANE FROM SHALLOW SUBMARINE SOURCES,Since methane| per mole| has a global warming potential 3.7 times that of carbon dioxide (LASHOF and AHUJA| 1990| Nature| 344| 529-531) it is one of the most important greenhouse gases in the atmosphere. It is therefore crucial to acquire a basic understanding of the natural global methane emission variability and inventory. Methane contained in and seeping from shallow marine sediments represents a vast| but largely uncharted source of ocean and atmospheric methane. A rough global estimate is made here on the amount of methane annually venting through the seabed from shallow marine sediments in water depths less than 250 m. The globally extrapolated estimate is based on observations of methane point sources in the North Sea. These estimates show that marine sediments probably represent an important but variable source of methane to the atmosphere. However| much more survey work and detailed measurements are needed before a more exact figure on total source strength and variability can be provided. 3728,1992,3,3,THE IEA GREENHOUSE GAS RESEARCH-AND-DEVELOPMENT PROGRAM,On 20th November 1991 a number of countries signed an agreement to take part in a programme of research and development aimed at potential mitigation techniques as a response to the issue of global warming. Formed under the aegis of the Intemational Energy Agency (IEA)| the programme brings together those countries interested in establishing the techniques| costs| and environmental consequences of removing CO2 from power station flue gases and storing or otherwise disposing it. Task 1 under the agreement is a three year programme covering a range of study and information dissemination activities which are described in the paper. The programme could culminate in proposals aimed at demonstration facilities should any of the technologies evaluated show sufficient promise.The project structure and work programme are described and a summary of progress to date is given. Technical study work at present in progress and planned for the future is described in outline. 3756,1992,2,3,THE IMPACT OF GLOBAL WARMING ON RIVER RUNOFF,River runoff from the world's major rivers is an important part of the hydrologic cycle. Runoff changes in response to global greenhouse-induced warming will have impacts in many areas| including agriculture| water resources| and land use. A global atmospheric model is used to calculate the annual river runoff for 33 of the world's major rivers for the present climate and for a doubled CO2 climate. The model has a horizontal resolution of 4-degrees x 5-degrees| but the runoff from each model grid box is quartered and added to the appropriate river drainage basin on a 2-degrees x 2.5-degrees resolution. The computed runoff depends on the model's precipitation| evapotranspiration| and soil moisture storage. For the doubled CO2 climate| the runoff increased for 25 to the 33 rivers| and in most cases the increases coincided with increased rainfall within the drainage basins. There were runoff increases in all rivers in high northern latitudes| with a maximum increase of 47%. At low latitudes there were both increases and decreases ranging from a 96% increase to a 43% decrease. The effect of the simplified model assumptions of land-atmosphere interactions on the results is discussed. 3734,1992,4,4,THE IMPACT OF SNOW COVER ON DIURNAL TEMPERATURE-RANGE,Many parts of the world are presently experiencing a decrease in the daily temperature range| and a number of investigators in the past have suggested that this change in climate may be related to the observed buildup of greenhouse gases. However| other geophysical variables| themselves related to increases in greenhouse gases| may be influencing the daily temperature range. In this investigation| we demonstrate a statistically significant| inverse correlation between the area of North American snow cover and the United States diurnal temperature range. Because global warming is expected to reduce the areal extent of snow cover| the results of this study reveal snow cover should act to increase the diurnal temperature range in the years to come. This climate variable appears therefore to be influencing the daily temperature range counter to other feedbacks discussed in previous studies. Ultimately| our work demonstrates that the direct linkage between the diurnal temperature range and greenhouse gases may be complicated by feedbacks associated with other geophysical variables. 3720,1992,2,3,THE LONG-TERM ECOLOGICAL EFFECTS OF POLLUTANTS - SOME ISSUES,In this paper we consider the long-term ecological effects of pollutants using three case-studies as examples: 'acid rain' and its effects on forests| soil and aquatic ecosystems; excess nitrogen deposition from the atmosphere and its effects on natural vegetation| and increased emission of CO2 and its possible climatic and ecological consequences. We point out that the scale of pollution arising from natural human functions is considerable given the size of the world human population. Additions to this background from industrial processes can be reduced considerably by technical means| but not eliminated entirely. The same 'contaminants' associated with industrial energy consumption (SO2| NOx| CO2) are also produced by natural processes. The sum of these three sources gives rise to a considerable 'irreducible' minimum background pollution level: the ecological consequences of this need to be explored further. 3675,1992,3,4,THE MAGNITUDE AND RELATIVE ENVIRONMENTAL-IMPACT OF AIR POLLUTANT EMISSIONS FROM AEROSOL INDUSTRY PRODUCTS,Aerosol industry products have in the past been a major source of CFC emissions. This situation has changed very rapidly and in developed countries CFC use has been eliminated other than in a few essential medical products. Current and likely future air pollutant emissions from aerosol industry products are evaluated in terms of their stratospheric ozone depletion potential| global warming potential and photochemical ozone creation potential. Environmental impacts of future emissions are likely to be minimal in comparison to those from other air pollution sources. 3768,1992,5,4,THE MESOZOIC HERBACEOUS LYCOPSIDS,Occurrences of lycopsid megafossils and their spores in the Mesozoic are reviewed. Subarborescent lepidodendralean forms diversified in the early Mesozoic before going extinct in the early Jurassic| although herbaceous| Isoetes-like forms-considered here also to be lepidodendraleans-survived to the present day as represented by the sole surviving genus Isoetes. Records of Isoetes-like forms from Triassic strata are considered questionable; the earliest good-quality examples that can currently be accepted are in the late Jurassic/early Cretaceous. The two other major groups of lycopsids that also survive today-the lycopodialeans and selaginellaleans-were present throughout the Mesozoic as entirely herbaceous forms. Some of them closely resemble extant species but most are less similar and some| such as Synlycostrobus with its apparently compound strobili| greatly extend our knowledge of lycopsid diversity. A few of the Mesozoic species appear to provide important and hitherto unsuspected links between there two major groups. Increasingly refined knowledge of late Paleozoic through Mesozoic lycopsids and their spores is contributing to growing precision in biostratigraphy and also in environmental changes that have affected our planet in the geological past| particularly the protracted interval of global warming that began in the late Paleozoic and continued throughout the Mesozoic. New information is presented on Mesozoic lycopsids from the United States and England| including a new species of Isoetites of Cretaceous age with well-preserved spores in situ. 3729,1992,2,4,THE ORIGIN OF REGIONAL ECOLOGICAL PROBLEMS WITHIN THE NORTHERN TYUMEN OBLAST| RUSSIA,The northern areas of the Western Siberia are subjected to intensive anthropogenic pressure| mainly by the oil and gas extraction industries| reindeer herding| hunting| and fishing. Localized activities| rather than regional-scale activities have led to the degradation of the natural environment on a regional scale. These processes include (1) transfer of pollutants by water and atmosphere; (2) expansion and merging of oil and gas development sites; (3) degradation of the key wildlife habitats (reproduction sites of fish| animals| birds| migration routes| etc.); and (4) more intensive use of remaining pastures and hunting areas by the indigenous population due to loss of large areas of pasture and hunting territories to the oil and gas industries. Analysis of the existing situation within northwest Siberia suggests that in future the situation will continue to worsen unless there is significant improvement in land-use management and technology of oil and gas industry. Degradation processes may also be exacerbated by global warming. Concurrently local changes themselves may lead to negative changes on the global scale. 3789,1992,3,2,THE PASSENGER CAR AND THE GREENHOUSE-EFFECT,Concern is mounting over the possibility of global warming from the greenhouse effect. Carbon dioxide (CO2) from the combustion of fossil fuel is a major greenhouse gas| and automobile exhaust is one of its contributors. The only way to decrease CO2 emissions from a car consuming carbonaceous fuel is to decrease its fuel consumption. The best alternative fossil fuels offer a CO2 reduction of about 20%. Without introducing any new greenhouse-gas controls| it is projected that the total greenhouse-gas contribution of the average car will be halved from recent levels just through fleet turnover and already planned elimination of the current air-conditioning refrigerant. If global warming develops into a serious problem| cars can be operated without fossil fuel. Leading options include battery-electric cars using nuclear power and engine-propelled cars burning biomass-derived alcohol or hydrogen extracted from water with solar cells or nuclear power. 3683,1992,3,4,THE POTENTIAL ROLE OF TEMPERATE FORESTS AS SINKS FOR CO2 - EXAMPLES FROM THE GERMAN ENVIRONMENTAL-POLICY AGAINST GLOBAL WARMING,Among industrialized nations Germany ranks fourth in CO2 emissions. Most of these originate from the use of fossil fuels. Based on reports of a parliamentary study commission| established in 1987| and other expert groups in Germany this article adresses possible environmental effects of increasing atmospheric CO2| the sink potential of temperate forests and the influence of forest damage on this potential. A strategy for a 25 to 30% or 250 to 300 X 10(6) t yr-1 CO2 emissions reduction by 2005 (which Germany has itself committed to) is described in which measures to enhance C sequestration by forests play an important role. Expansion of forest area| a further increase of C storage by appropriate management and the restoration and protection of forest health impaired by air pollution would result in an additional storage of 17 to 20 x 10(6) t yr-1 of CO2| equaling 6 to 8% of the reduction target. 3725,1992,3,3,THE PRESENT STATUS OF CARBON-DIOXIDE REMOVAL IN JAPAN,The Action Program of Japan to arrest global warming was announced on October of 1990. As a core research organization for the purpose of tackling the growing threat the global environment problems| the research Institute of Innovative Technology for the Earth (RITE) was established. In Japan many national laboratories| universities and private companies research new technologies and develop new processes for mitigating global warming. The present status of the research and development on CO2 removal and disposal technologies in Japan is described. 3641,1992,2,4,THE PROBABLE EFFECTS OF CLIMATE-CHANGE ON INVERTEBRATE GROWTH AND REPRODUCTION WITH PARTICULAR REFERENCE TO IRELAND,The variability of the mild Irish climate is described. The effect of a slight rise in temperature is discussed as far as aquatic organisms are concerned. The effect is likely to be most marked on pelagic populations of marine organisms such as squid and also on intertidal animals. A rise in mean sea level is an indirect result of global warming| and this is likely to have an effect on estuarine organisms and mud flat dwellers. It is suggested that those organisms which are close to the southern limits of their distribution in Ireland may disappear from our fauna. Examples are given from earlier periods and from the present-day fauna. There is likely to be an expansion of the distribution of southern forms which at the moment are near the northern limit of their range. As far as terrestrial animals are concerned| the problem of whether the rainfall pattern will also change is discussed. The likely effects of this on parasite and free-living populations (including the fauna of temporary water bodies| common in West Ireland) are discussed. The complications introduced by diapause and related factors are considered. The fauna of peat bogs may be seriously affected and also those organisms dependent on certain food plants. The peculiar problems of Ireland in having so many empty niches is considered in relation to the increased dangers of accidental introductions. 3645,1992,4,3,THE RESPONSE OF ANTARCTIC CLIMATE IN GENERAL-CIRCULATION MODEL EXPERIMENTS WITH TRANSIENTLY INCREASING CARBON-DIOXIDE CONCENTRATIONS,Coupled models of the atmosphere-ocean and land surface provide important tools for prediction of climate change. The results of experiments carried out at the Hadley Centre| Meteorological Office| in which such models have been used in studies of climate change due to increased levels of greenhouse gas concentrations are described| with particular reference to simulation of climate change in the region of Antarctica. Although| as yet| the ability of such models to represent regional climate change is relatively low| processes in the southern ocean around Antarctica are important for determining the global pattern of transient temperature change as CO2 increases. This is illustrated by results from two experiments. Firstly| an experiment with a high resolution (2.5-degrees x 3.75-degrees) atmospheric model coupled to a simple slab ocean in which the response of climate to an instantaneous doubling of greenhouse gas concentrations was examined| and which showed the largest induced warming to be in the polar regions in winter similar to the results of previous experiments carried out at the Meteorological Office and elsewhere. However| an experiment with a deep ocean model and a (more realistic) 1% per annum increase in greenhouse gas concentrations shows the pattern of global warming to be shifted to give minimum values around Antarctica as a result of deep oceanic mixing processes in the southern ocean| consistent with similar experiments carried out at other centres. 3646,1992,5,4,THE SEDIMENTARY RECORD OF ANTARCTIC CLIMATE CHANGE,Circum-Antarctic marine sediments contain a record of past climate and Southern Ocean circulation that both complements and considerably extends the record in the continental ice. Variations in primary biological production| reflecting changes in sea-ice cover and sea surface temperature| in bottom current strength and the size of the grounded continental ice sheet| all contribute to changes in sediment characteristics| in a record extending back many million years. It is possible to assess both the value of the proxy record in Antarctic sediments| and the validity of the analogue approach to understanding climate change| by focusing on the last glacial cycle and| for comparison| on earlier periods that were significantly different: the Pliocene before 3 Ma ago that could provide an analogue for global warming| and the Oligocene before there was an Antarctic Circumpolar Current. 3718,1992,2,2,THE SOCIAL AND PUBLIC-HEALTH IMPLICATIONS OF GLOBAL WARMING AND THE ONSLAUGHT OF ALIEN SPECIES,Humans are engaged in an uncontrolled experiment in planetary heating. Each decade| the concentration of CO2| methane and other greenhouse gases in the atmosphere is increasing by about 4%. All signs point toward unprecedented rates of warming and climate change. Many plant and animal species living in natural ecosystems will perish because they will be unable to keep up with shifting climatic zones. Warming exacerbates another biomedical problem - the influx of alien animals| plants and pathogens. These introduced species| many from the tropics| will not only increase the variety and incidence of tropical diseases| but will also affect the quality of the wilderness experience and hence| the popularity of outdoor recreation. Some personal actions and political prophylaxis are recommended. 3647,1992,5,4,THE SOUTHERN-OCEAN BENTHIC FAUNA AND CLIMATE CHANGE - A HISTORICAL-PERSPECTIVE,Environmental change is the norm and it is likely that| particularly on the geological timescale| the temperature regime experienced by marine organisms has never been stable. These temperature changes vary in timescale from daily| through seasonal variations| to long-term environmental change over tens of millions of years. Whereas physiological work can give information on how individual organisms may react phenotypically to short-term change| the way benthic communities react to long-term change can only be studied from the fossil record. The present benthic marine fauna of the Southern Ocean is rich and diverse| consisting of a mixture of taxa with differing evolutionary histories and biogeographical affinities| suggesting that at no time in the Cenozoic did continental ice sheets extend sufficiently to eradicate all shallow-water faunas around Antarctica at the same time. Nevertheless| certain features do suggest the operation of vicariant processes| and climatic cycles affecting distributional ranges and ice-sheet extension may both have enhanced speciation processes. The overall cooling of southern high-latitude seas since the mid-Eocene has been neither smooth nor steady. Intermittent periods of global warming and the influence of Milankovitch cyclicity is likely to have led to regular pulses of migration in and out of Antarctica. The resultant diversity pump may explain in part the high species richness of some marine taxa in the Southern Ocean. It is difficult to suggest how the existing fauna will react to present global warming. Although it is certain the fauna will change| as all faunas have done throughout evolutionary time| we cannot predict with confidence how it will do so. 3775,1992,3,4,THE SUGAR-CANE AGROINDUSTRY - ITS CONTRIBUTION TO REDUCING CO-2 EMISSIONS IN BRAZIL,Production of sugar cane in Brazil is 222 million tonnes (harvested wet weight)/year and is processed to sugar (7.5 million tonnes) and ethanol (11.8 million m3) in 1990. The use of fossil fuels in sugar cane production is 271 MJ/t of cane. Sugar cane bagasse and ethanol substitute for fuel oil in the food and chemical industry (including sugar production) and for gasoline (9.75 million m3/year)| thus avoiding CO2 emissions from fossil fuels. Considering the fast carbon cycling in sugar cane production and use| net emissions of 9.45 million tonnes of C/year are avoided; this corresponds roughly to 18% of the total CO2 emissions from fossil fuels in Brazil. 2185,1992,2,4,THE TRANSIENT-RESPONSE OF VEGETATION TO CLIMATE CHANGE - A POTENTIAL SOURCE OF CO2 TO THE ATMOSPHERE,Global climate change as currently simulated could result in the broad-scale redistribution of vegetation across the planet. Vegetation change could occur through drought-induced dieback and fire. The direct combustion of vegetation and the decay of dead biomass could result in a release of carbon from the biosphere to the atmosphere over a 50- to 150-year time frame. A simple model that tracks dieback and regrowth of extra-tropical forests is used to estimate the possible magnitude of this carbon pulse to the atmosphere. Depending on the climate scenario and model assumptions| the carbon pulse could range from 0 to 3 Gt of C yr-1. The wide range of pulse estimates is a function of uncertainties in the rate of future vegetation change and in the values of key model parameters.
3712,1992,4,3,THE UNITED-STATES-DEPARTMENT-OF-ENERGY AND THE PEOPLES-REPUBLIC-OF-CHINA-ACADEMY-OF-SCIENCES JOINT RESEARCH ON THE GREENHOUSE-EFFECT - 1985-1991 RESEARCH PROGRESS,The U.S. Department of Energy and the People's Republic of China's Academy of Sciences signed an agreement on 19 August 1987 to carry out a joint research program on the study of global warming due to enhanced greenhouse effect. The joint study is a first step toward providing opportunities for scientists in both countries to share climate information leading to a better understanding of the earth's climate system and to reliable regional climate prediction. The joint program has four tasks-analysis of general circulation models (GCMs)| preparation and analysis of proxy and instrumental data| the study of the relationship between large- and regional-scale climates| and measuring and analyzing methane emissions from rice paddy fields in China. Significant progress is being made| and this paper summarizes the research progress since 1985| including two years of scientist-to-scientist collaboration. Overall| there are over 120 publications documenting project research. Highlights of the accomplishments are described and future collaborative work is outlined. 3787,1992,3,2,THE USE OF IRON AND OTHER TRACE-ELEMENT FERTILIZERS IN MITIGATING GLOBAL WARMING,If current trends continue| before the end of the next century atmospheric CO2 levels will be about double those of a century ago. Other greenhouse gases| including methane and chlorofluorocarbons| also are increasing at similar or even higher rates. The effects of such global atmospheric changes on climate| and| thus| on agriculture| forestry and natural ecosystems| are uncertain. Only the results of the planetary "experiment" itself will provide a definitive answer. Current projections range from catastrophic to favorable. Prudence suggests that steps be taken to slow down these rapid atmospheric changes| even in the absence of a definitive estimate of risks. Natural sinks for CO2 already account for the disappearance of as much as 60% of anthropogenic CO2 production due to fossil fuel combustion| deforestation| and soil organic carbon oxidation. Thus| current rates of increases in atmospheric CO2| about 0.4% per year| could be cut in half by reducing anthropogenic CO2 outputs by 20%| or increasing sinks by a similar amount. Such a reduction would significantly reduce the risks of major climatic changes. Programs to reduce greenhouse gas emissions are being instituted in Japan and Europe| but not in the U.S. or most other countries. Reduction of CO2 buildup must focus on the reduction of the major sources - fossil fuel usage| deforestation| soil carbon oxidation - and on increasing sinks. The only practical methods for increasing CO2 sinks are based on photosynthesis| primarily through increased C storage in standing tree biomass| the use biomass as substitutes for fossil fuels| and| possibly| through the stimulation of ocean primary productivity by iron fertilization. Fertilizing forests and oceans with iron and other trace elements to increase primary productivity and CO2 sequestration is an attractive concept. Application of small quantities of trace elements| could| in principle| result in the sequestration of many tons of CO2. Iron limits primary productivity in some ocean areas. How to practically fertilize the oceans with iron| the environmental impacts of such additions| and their effectiveness in reducing atmospheric CO2 concentrations are controversial issues. Long-term studies of ocean fertilization will be required| and such schemes can not be included in current global warming mitigation options. Iron and other trace elements are often limiting factors in agriculture| and many reports exist of such limitations in managed forestry. However| it is presently unclear how widespread such deficiencies are in managed forests| and global effects on CO2 balances can not be projected. Fertilization with major nutrients - P| K| and N - is often effective in stimulating forest productivity and could be an economical approach to large-scale CO2 sequestration. Increased forest fertilization with major nutrients will| in many cases| also require applications of some trace elements. In conclusion| forest fertilization with trace elements and even major nutrients could be an affordable and near-term method of reducing future global warming. 2216,1992,4,4,THE USE OF NATURAL C-14 AND C-13 IN SOILS FOR STUDIES ON GLOBAL CLIMATE CHANGE,Some examples are given to show that the depth distribution curves of natural C-14 and C-13 of thin-layer sampled soil profiles can be used for inferring changes in soil organic matter and climate changes. By using a simple exchange model| we r-an determine whether decomposition products are fixed by clay or transported downward toward the groundwater table. We can also estimate the amount of the Greenhouse gases| CO2 and CH4| produced by the decomposition of the organic matter in terrestrial and paddy soils and emitted from the soil. A change from C3 to C4 plants| which might occur during a predicted temperature rise in some areas| thereby influencing the carbon balance| can be clearly detected by the deltaC-13 depth profiles. A change in organic matter input can also be calculated under certain circumstances.
3770,1992,4,4,THE WORK INTENSITY FUNCTION IN THE DETECTION OF GREENHOUSE INDUCED GLOBAL TEMPERATURE TRENDS,A work intensity function is defined as the product of the frequencies exhibited by a column in a histogram and the magnitude of the midpoint of the class interval of the column. An intensity distribution is defined as the cumulative sum of the function along the abscissa. These functions are examined first for a normal distribution| and then for the expected deviations shown by a sample assumed to be drawn from a normal distribution. The theoretical maximum of the intensity is found at one standard deviation for the normal distribution and at square-root 2 s.d. (standard deviation) for a sample drawn from a normal distribution. The cumulative sum of the intensity is more biased towards outlying values of larger magnitude for the sample than for the normal distribution. 10% of the cumulative sum of the intensities is generated at s.d. greater than 3 for the sample compared to only 1% for the normal distribution itself. These statistics are compared with similar ones computed for the Jones-Parker (1991) series of mean global surface temperature anomaly interannual differences. The agreement between theory and the data series is good. The data series appears to possess those properties which would be expected of it if the series was a sample drawn from a normal distribution. It is concluded that the work intensity and its cumulative sum are useful tools in diagnosing the behaviour of a population of anomaly values. These statistics do not clarify the problem of identifying a greenhouse gas induced global warming but they do suggest that its identification continues to be as difficult as ever| due to the effect of occasional outlying values. 3644,1992,4,4,THERMAL-DIFFUSIVITY OF THE ALTERNATIVE REFRIGERANTS R123| R134A| R142B AND R152A IN THE LIQUID-PHASE,The thermal diffusivity of the refrigerants 1|1-dichloro-2|2|2-trifluoroethane (R123)| 1|1|1|2-tetrafluoroethane (R134a)| 1|1-difluoroethane (R152a) and 1-chloro-1|1-difluorethane (R142b) with low ozone depletion potential (ODP) and low global warming potential (GWP) has been measured at different pressures in a wide temperature range below the critical point. These substances are proposed as substitutes for the traditional refrigerants especially R123 for Rll| R134a and R152a for R12 and R142b for R114. The measurements were carried out using the photon correlation spectroscopy (PCS). The measured values of the thermal diffusivity axe presented as a function of temperature and compared with those of the traditional refrigerants. The thermal diffusivities of the possible substitutes can be up to 70% higher or lower than the traditional refrigerants. 3707,1992,3,4,THROWING STONES IN THE GREENHOUSE,The debate about global warming has only recently developed into a truly 'global' debate. Recent reports and commentaries coming from the South have presented the developing countries' perspective on the global situation. The current debate challenges assumptions in the North and suggests that all countries should look first to their own role in the development of the problem| and the solution to it.
3636,1992,4,2,TIME-DEPENDENT GREENHOUSE WARMING COMPUTATIONS WITH A COUPLED OCEAN-ATMOSPHERE MODEL,Climate changes during the next 100 years caused by anthropogenic emissions of greenhouse gases have been simulated for the Intergovernmental Panel on Climate Change Scenarios A ("business as usual") and D ("accelerated policies") using a coupled ocean-atmosphere general circulation model. In the global average| the near-surface temperature rises by 2.6 K in Scenario A and by 0.6 K in Scenario D. The global patterns of climate change for both IPCC scenarios and for a third step-function 2 x CO2 experiment were found to be very similar. The warming delay over the oceans is larger than found in simulations with atmospheric general circulation models coupled to mixed-layer models| leading to a more pronounced land-sea contrast and a weaker warming (and in some regions even an initial cooling) in the Southern Ocean. During the first forty years| the global warming and sea level rise due to the thermal expansion of the ocean are significantly slower than estimated previously from box-diffusion-upwelling models| but the major part of this delay can be attributed to the previous warming history prior to the start of present coupled ocean-atmosphere model integration (cold start). 3663,1992,2,4,TIMING AND PATTERNS OF VISIBLE AUTUMN MIGRATION - CAN EFFECTS OF GLOBAL WARMING BE DETECTED,For 21 years| diurnal migration of 46 bird species was observed under standardized conditions at Randecker Maar| SW Germany. The data are examined as to whether changes in median dates of passage of these species can be detected. For this purpose the data were analysed separately for three periods| i. e. 1970-76| 1977-83 and 1984-90. In 1970 to 1983| according to meteorological data the weather-related onset of autumn was delayed by five days in northern Germany and by six days in southern Germany. During the last observation period| 19 (67 %) of the 28 passerine short-distance migrants passed on average up to 10 days later compared to the first observation period. In 14 of these species the median dates changed continuously. Only 5 species migrated earlier than before- The majority of the short-distance migrants| therefore| seems to have adapted to the later onset of autumn. Currently there seem to be no plausible reasons for delayed migration other than climatic changes. The median dates in Non-Passerines were less clear-cut. Among short-distance migrants| delayed migration was found in 5| advanced migration in 4 species and among long-distance migrants| delayed migration was noted in 4 species| advanced migration in 3 species. Short-distance migrants may gain advantages from a longer stay on their Central European breeding grounds. Populations departing late should tend to become resident| thus advancing the median date for the fractions of population still migrating. Even advanced migration may thus be explained by global warming. Long-distance migrants| however| may only occasionally profit from a longer stay on their breeding grounds. Their arrival south of the Sahara coinciding with the short monsoon rainfalls probably has greater selective significance| Deviations in arrival times caused by climatic changes may thus lead to catastrophies as is currently discussed in the case of Tawny Pipit. The influence of global warming on bird migration and the changes in migration patterns ensuing from it were to be expected after laboratory results. Here| this influence is shown in a long-term study of free-living populations of a large number of species. 3784,1992,2,4,TO LIVE IN HARMONY WITH THE SEA - AN ENVELOPMENT STRATEGY FOR THE NEXT 3 GENERATIONS,The severe urban development pressures on Japanese coastal zones are epitomized in Sagami Bay| one of Tokyo's key recreational destinations. Besides facing grave uncertainties of global warming and tectonic dynamics| this 30-km coastal zone is a stage of many conflicts: between residential growth and recreational facilities| between dwindling natural beach sites and highway construction| and between watersports and fishery. Outlined here is a radical approach in eight steps| to be implemented over the next three generations. It calls for the abolishment of conventional development ideas in favor of the concept of "envelopment" instead. This article is derived from the top prize-winning entry to an international idea contest that generated 293 proposals from 27 countries| as well as thousands of children's drawings. It was sponsored by the Sagamiwan Urban Resort Festival in 1990 Association| the Kanagawa Prefectural Government| as well as by the city authorities and municipal governments of Yokosuka| Hiratsuka| Fujisawa| Odawara| Chigasaki| Zushi| Miura| Hayama| Oiso| Ninomiya| Manazuru| and Yugawara. Additional support was provided by the American Shore and Beach Preservation Association| the Coastal Zone Foundation| and the International Coastal and Ocean Organization. 2178,1992,4,4,TOGA COARE - THE COUPLED OCEAN ATMOSPHERE RESPONSE EXPERIMENT,Despite significant progress in the Tropical Ocean-Global Atmosphere (TOGA) program| a number of major hurdles remain before the primary objective| prediction of the variability of the coupled ocean-atmosphere system on time scales of months to years| can be achieved. Foremost among these hurdles is understanding the physics that maintains and perturbs the western Pacific warm pool| the region of the warmest sea surface temperature in the open oceans| which coexists with the largest annual precipitation and latent heat release in the atmosphere. Even though it is believed that the warm pool is a "center of action" for the El Nino-Southern Oscillation (ENSO) phenomena in the ocean and the atmosphere| successful simulation of the warm pool has remained an elusive goal. To gain a clear understanding of global climate change| the ENSO phenomenon| and the intraseasonal variability of the coupled atmosphere-ocean system| it is clear that a better specification of the coupling of the ocean and the atmosphere is required. An observational and modeling program| the TOGA Coupled Ocean-Atmosphere Response Experiment (TOGA COARE)| has been designed to work toward this goal. The scientific goals of COARE are to describe and understand: 1) the principal processes responsible for the coupling of the ocean and the atmosphere in the western Pacific warm-pool system; 2) the principal atmospheric processes that organize convection in the warm-pool region; 3) the oceanic response to combined buoyancy and wind-stress forcing in the western Pacific warm-pool region; and 4) the multiple-scale interactions that extend the oceanic and atmospheric influence of the western Pacific warm-pool system to other regions and vice versa. To carry out the goals of TOGA COARE| three components of a major field experiment have been defined: interface| atmospheric| and oceanographic. An intensive observation period (IOP)| embedded in a period of enhanced meteorological and oceanographic monitoring| will occur from November 1992 through February 1993 in the western Pacific region bordered by 10-degrees-N| 10-degrees-S| 140-degrees-E| and the date line. The experimental design calls for a complex set of oceanographic and meteorological observations from a variety of platforms that will carry out remote and in situ measurements. The focus of the observational effort will be in an intensive flux array (IFA) centered at 2-degrees-S and 156-degrees-E. The resulting high-quality dataset is required for the calculation of the interfacial fluxes of heat| momentum| and moisture| and to provide ground truth for a wide range of remotely sensed variables for the calibration of satellite-derived algorithms. The ultimate objective of the COARE dataset is to improve air-sea interaction and boundary-layer parameterizations in models of the ocean and the atmosphere| and to validate coupled models.
3735,1992,2,4,TOWARD A RULE-BASED BIOME MODEL,Current projections of the response of the biosphere to global climatic change indicate as much as 50% to 90% spatial displacement of extratropical biomes. The mechanism of spatial shift could be dominated by either 1) competitive displacement of northern biomes by southern biomes| or 2) drought-induced dieback of areas susceptible to change. The current suite of global biosphere models cannot distinguish between these two processes| thus determining the need for a mechanistically based biome model. The first steps have been taken towards the development of a rule-based| mechanistic model of regional biomes at a continental scale. The computer model is based on a suite of empirically generated conceptual models of biome distribution. With a few exceptions the conceptual models are based on the regional water balance and the potential supply of water to vegetation from two different soil layers| surface for grasses and deep for woody vegetation. The seasonality of precipitation largely determines the amount and timing of recharge of each of these soil layers and thus| the potential mixture of vegetative life-forms that could be supported under a specific climate. The current configuration of rules accounts for the potential natural vegetation at about 94% of 1211 climate stations over the conterminous U.S. Increased temperatures| due to global warming| would 1) reduce the supply of soil moisture over much of the U.S. by reducing the volume of snow and increasing winter runoff| and 2) increase the potential evapotranspiration (PET). These processes combined would likely produce widespread drought-induced dieback in the nation's biomes. The model is in an early stage of development and will require several enhancements| including explicit simulation of PET| extension to boreal and tropical biomes| a shift from steady-state to transient dynamics| and validation on other continents. 2206,1992,2,3,USE OF A RESERVOIR WATER-QUALITY MODEL TO SIMULATE GLOBAL CLIMATE CHANGE EFFECTS ON FISH HABITAT,A case study was conducted on the potential impacts of climate change on fish habitat in a southeastern reservoir. A reservoir water quality model and one year of baseline meteorologic| hydrologic| and inflow water quality input were used to simulate current reservoir water quality. Total adult striped bass habitat| defined by specific quantitative temperature and dissolved oxygen criteria| was simulated. Daily reservoir volumes with optimal| suboptimal| and unsuitable temperature and DO were predicted for the year. Output from recent runs of atmospheric general circulation models (GCMs)| in which atmospheric carbon dioxide concentrations have been doubled| was then used to adjust the baseline inputs to the water quality model. New sets of input data were created for two grid cells for each of three GCMs. All six climate scenarios are predicted to cause overall declines in the available summer striped bass habitat| mostly due to lake water temperatures exceeding striped bass tolerance levels. These predictions are believed to result from the consensus among GCM scenarios that air temperatures and humidity will rise| and the sensitivity of the reservoir model to these parameters. The reservoir model was found to be a promising tool for examining potential climate-change impacts. Some of the assumptions required to apply GCM output to the reservoir model| however| illustrate the problems in using large-scale grid-cell output to assess small-scale impacts.
3670,1992,2,4,USING MONTANE MAMMALS TO MODEL EXTINCTIONS DUE TO GLOBAL CHANGE,We use data on the species-area relationship and the nested subset structure of the boreal mammal faunas inhabiting isolated mountaintops in the Great Basin to develop a simple quantitative model that predicts the number and identity of species that would go extinct under an assumed scenario of changing climate and vegetation Global warming of 3-degrees-C is predicted to cause the loss of 9-62% of the species inhabiting each mountain range and the extinction of three of fourteen species throughout the region. These results suggest (1) that it is possible to make highly plausible predictions about the susceptibility of species to extinction without detailed information about their population biology| and (2) that global and regional environmental changes seriously threaten the survival of species that are restricted in distribution to both natural "habitat islands" and biological reserves. 3638,1992,2,4,VARIATION IN NUCLEAR-DNA AMOUNT BETWEEN WILD AND CULTIVATED POPULATIONS OF MILIUM-EFFUSUM (2N = 28),Mean 2C DNA amounts varied by 35.6%| ranging from 7.52 to 10.20 pg| between 10 populations of the grass Milium effusum L. Such intraspecific variation occurred despite a constant chromosome number (2n = 28) and no obvious differences in karyotype. Plants originating from botanic garden populations growing in cultivation had significantly (P < 0.001) larger DNA amounts than plants collected from wild populations. Moreover| variation in DNA amount within either the ''cultivated'' or the ''wild'' groups was not significant. As the environment in which plants are kept in botanic gardens is clearly different to the natural habitat for M. effusum| it seems likely that the difference in nuclear DNA amount is causally related| perhaps through its nucleotypic effects| to microclimate adaptation. These results suggest that at least some genotypes of M. effusum are fluid and sensitive to environmental change. Such data may have broad practical importance regarding plant responses to various environmental changes such as a nuclear winter and global warming| and implications for plant conservation and reintroduction. Milium effusum is a potentially useful plant material for studying the nature of intraspecific variation in DNA amount. 3681,1992,4,3,WHY UNDERSTANDING THE NATURAL SINKS AND SOURCES OF CO2 IS IMPORTANT - A POLICY ANALYSIS PERSPECTIVE,The mechanisms that regulate the concentration of carbon dioxide in the atmosphere| the carbon cycle| is an integral part of the analysis of the greenhouse issue. The present understanding of the carbon cycle is inadequate to the purpose of assessing the relationship between future anthropogenic emissions and concentrations of atmospheric CO2. The most important problem is that natural science cannot presently explain the relationship between present and past anthropogenetic emissions and concentrations. Sinks for CO2 are inadequate to explain present and past dispositions of emissions. This deficiency in scientific understanding leads to uncertainty in the analysis of potential future emissions and atmospheric CO2 accumulation| and to uncertainty in the specification of other policy analysis instruments such as global warming potential coefficients. 2177,1992,3,3,WORLD OIL AND ENERGY DEMAND OUTLOOK TO 2005,The outlook for world oil demand is examined within a framework which takes account of total energy demand and the availability of oil supplies over the period to 2005. The major assumptions and uncertainties| as well as the model and rationale which underly the outlook| are discussed. The analysis points to a 30% rise in world oil demand and an 85% rise in the demand for Middle East oil between now and 2005| with a concomitant gradual rise in influence of Middle East producers over oil prices. However| major new global initiatives by governments| for example to mitigate climate change| could significantly alter the outlook by appreciably reducing the future growth in oil demand.
4018,1993,3,4,A CATALYTIC PROCESS FOR THE DECOMPOSITION OF NITROUS-OXIDE,Environmental issues such as global warming and ozone layer depletion are now of universal concern. One compound not previously associated with these concerns is nitrous oxide (N2O). Worldwide efforts to reduce anthropogenic emissions are underway. One industrial application that has recently emerged is N2O abatement from adipic acid plants (in connection with nylon 6|6 manufacture). One possible solution| the catalytic decomposition of N2O| has long been studied but mainly from an academic standpoint. Some catalysts based on the earlier work were evaluated under pseudo-industrial conditions. It is concluded that many factors (e.g. intrinsic activity| stability| selectivity) limit the choice of catalyst for this application and that any useful catalyst should be operated within the confines of a process to reduce the rate of thermal deactivation and suppress secondary reactions such as NOx formation. This paper highlights the features of a catalyst and a catalytic process that can be used to effectively decompose N2O into its constituent parts| namely nitrogen and oxygen. The catalytic process is offered for license under the ElimiNox service mark. 2677,1993,2,4,A GENERAL RELATIONSHIP BETWEEN CO2-INDUCED REDUCTIONS IN STOMATAL CONDUCTANCE AND CONCOMITANT INCREASES IN FOLIAGE TEMPERATURE,Simultaneous measurements of the temperatures and stomatal conductances of leaves of sour orange trees growing in normal and CO2-enriched air| together with similar data for water hyacinths and cotton| suggest that a plant's foliage temperature response to atmospheric CO2-enrichment is directly proportional to its degree of stomatal closure| i.e. that plants that experience a greater stomatal closure in response to atmospheric CO2 enrichment experience a greater warming of their foliage. The data also suggest that this primary relationship may be modified by CO2-induced changes in leaf chlorophyll content that may have implications for global climate change.
4076,1993,4,3,A GUIDE TO GLOBAL WARMING POTENTIALS (GWPS),In order to quantitatively compare the greenhouse effect of different greenhouse gases a global warming potential (GWP) index has been used which is based on the ratio of the radiative forcing of an equal emission of two different gases| integrated either over all time or up to an arbitrarily determined time horizon. The GWP index is analogous to the ozone depleting potential (ODP) index. However| the GWP index is subject to major conceptual difficulties arising from the fact that the atmospheric lifespan for part of the emitted CO2 is| for all practical purposes| infinite. In addition| there are major uncertainties in the atmospheric lifespans and indirect heating effects of the important greenhouse gases| which are reviewed here. An alternative GWP index is proposed which explicitly takes into account the duration of capital investments in the energy sector and is less sensitive to uncertainties in atmospheric lifespans and radiative heating than the usual GWP index for time horizons longer than the lifespan of the capital investment. The effect of the GWP index proposed here| compared with previous indices| is to shift attention away from short lived gases such as methane and toward CO2. 4009,1993,5,3,A MODEL STUDY OF ATMOSPHERIC TEMPERATURES AND THE CONCENTRATIONS OF OZONE| HYDROXYL| AND SOME OTHER PHOTOCHEMICALLY ACTIVE GASES DURING THE GLACIAL| THE PREINDUSTRIAL HOLOCENE AND THE PRESENT,Analysis of air trapped in ice cores shows that the atmospheric contents of the greenhouse gases CO2| CH4 and N2O have increased from the glacial to the pre-industrial holocene. Further increases have been occurring during the industrial era. This may well have contributed to the observed global warming. In addition| CH4 and N2O play large roles in ozone and hydroxyl chemistry. Here we present a model analysis of the changes in atmospheric temperatures and the concentration of O3| OH and related gases between the three epochs. Surprisingly| despite large changes in the atmospheric contents of CO2| CH4 and N2O| total ozone and tropospheric OH hardly changed between the glacial and pre-industrial holocene. The global annual atmospheric CH4 sink increased from 90 to 210 Tg (10(12) g) between the glacial and pre-industrial and since then to 510 Tg| largely following the changes in atmospheric concentrations. The corresponding figures for N2O are 7.8| 11.6 and 13.3 Tg. Our results indicate less than half as much CH4 production from tropical wetlands during the ice age than during the holocene. 3967,1993,4,4,A NEW CLOCHE DESIGN FOR ELEVATING TEMPERATURE IN POLAR TERRESTRIAL ECOSYSTEMS,A clocbe design is described that is suitable for elevating temperature to simulate global warming in polar ecosystems. This cloche system was used in a manipulation experiment near Ny Alesund| Spitsbergen| Svalbard. An average warming of 2.8 deg. C. was produced over a 60 day growing season| well within the range predicted by present climate models. The elevation effect is shown to be consistent over the diel cycle and throughout the short arctic summer season. Several advantages over previous designs of manipulation unit are highlighted. 4010,1993,4,4,A NEW PERSPECTIVE ON RECENT GLOBAL WARMING - ASYMMETRIC TRENDS OF DAILY MAXIMUM AND MINIMUM TEMPERATURE,Monthly mean maximum and minimum temperatures for over 50% (10%) of the Northern (Southern) Hemisphere landmass| accounting for 37% of the global landmass| indicate that the rise of the minimum temperature has occurred at a rate three times that of the maximum temperature during the period 1951-90 (0.84-degrees-C versus 0.28-degrees-C). The decrease of the diurnal temperature range is approximately equal to the increase of mean temperature. The asymmetry is detectable in all seasons and in most of the regions studied. The decrease in the daily temperature range is partially related to increases in cloud cover. Furthermore| a large number of atmospheric and surface boundary conditions are shown to differentially affect the maximum and minimum temperature. Linkages of the observed changes in the diurnal temperature range to large-scale climate forcings| such as anthropogenic increases in sulfate aerosols| greenhouse gases| or biomass burning (smoke)| remain tentative. Nonetheless| the observed decrease of the diurnal temperature range is clearly important| both scientifically and practically. 4060,1993,2,4,A POSSIBLE MECHANISM RELATING INCREASED SOIL-TEMPERATURE TO FOREST DECLINE,Nutrient cations are removed from the soil by uptake in biomass| and by leaching as a result of soil acidification. Such acidification results from acid deposition and/or from HNO3 formed by mineralization and nitrification of humus| when at a rate in excess of the tree's nutritional requirements. This has been found to occur during and follwing periods of increased temperature and reduced rainfall. The cumulative loss of either Ca2+| Mg2+ or K+ by one or more of these processes| if greater than the amount released from the specific minerals in that soil| leads to nutrient deficiency| fine root mortality| poor growth| and eventually to die-back. Trees growing in soils derived from specific minerals in which there is a strong imbalance in the elements from which the exchangeable nutrients are formed| are vulnerable to nutrient deficiency. This paper discusses the relevance of earlier studies| when considered in relation to more recent findings. In Hawaii there have been frequent periods of increased temperature and drought resulting from the El Nino Southern Oscillation. This fact| when considered in relation to the relatively low K content| and its imbalance with Ca and Mg in the lava and volcanic ash on which the trees have grown| could result in K deficiency in the declining ohia trees. It is possible that the unusual periods of increased temperature and drought which have occurred in certain other localized areas may have led to the decline symptoms recently observed. In view of the threat of global warming| this possibility should be investigated. 4033,1993,2,4,A PRELIMINARY NOTE ON RAINFALL AND VEGETATION TRENDS IN THE SOUTH-WESTERN CAPE - 1985-1988,Changes in the distribution of vegetation and rainfall over the south-western Cape from 1985 to 1988 were analysed. The density of photosynthetically active biomass was determined from visible satellite imagery using internationally accepted algorithms. Trends in rainfall were evaluated on the coastal plain to the south of 33-degrees-S and over the elevated interior to the north of 33-degrees-S. During the study period| rainfall exhibited a declining trend over the coastal plains. In contrast| the elevated interior experienced a three-fold increase. In response| photosynthetic activity within the coastal belt declined| whereas the interior Karoo region was replenished with vegetation including savanna-type shrubs and grasses. Changes in the distribution of rainfall and vegetation may be explained by a southward shift of the sub-tropical and mid-latitude climate zones. Such a shift could become a permanent feature in a global-warming scenario| and focusses attention on the plight of marginal agricultural zones in the face of increasing drought and human stress. 4029,1993,3,3,A PROPOSAL FOR THE CLASSIFICATION OF TOXIC-SUBSTANCES WITHIN THE FRAMEWORK OF LIFE-CYCLE ASSESSMENT OF PRODUCTS,Quantitative life cycle assessment (LCA) is a method allocating the environmental impacts of the whole life cycle of a product to the functioning of that product. The scientific basis of the method is still being elaborated. In this paper a proposal is made to improve the scientific basis of one specific step of the method: the aggregation of potentially toxic emissions of substances in one score for human toxicity and two scores for ecotoxicity. The aggregation is based on multimedia environmental models of Mackay simulating the behaviour of substances in the environment| and on toxicity data such as acceptable resp. tolerable daily intake (ADI resp. TDI) and no observed effect concentration (NOEC) per substance. It is proposed to apply models describing the environmental fate of toxic substances in LCAS Of products. In addition| it is proposed to adopt the concept of a reference substance| as used in the ozone depletion potential (ODP) and the global warming potential (GWP)| to assess and aggregate emissions of potentially toxic substances. 4062,1993,4,4,A REEXAMINATION OF THE POLAR HALOCLINE CATASTROPHE AND IMPLICATIONS FOR COUPLED OCEAN ATMOSPHERE MODELING,In this paper| the physical mechanism of the polar halocline catastrophe (PHC) is reexamined with emphasis on the role played by the surface heat flux. It is argued that| in a coupled ocean-atmosphere system| thermal changes in the atmospheric state in response to changes in heat flux from the ocean weaken the feedback responsible for the PHC. So far| the PHC has been observed in models that use mixed boundary conditions; that is| the freshwater flux is specified| but the surface temperature is relaxed to a specified value. Previous explanations of the PHC have focused on the role of the freshwater flux in establishing a freshwater cap and shutting off the deep convection. However| the establishment of a freshwater cap reduces the depth of the water column that is cooled by surface heat loss. As a consequence| the surface temperature is reduced. Since the difference between this and atmospheric restoring temperature is now less| there is a corresponding reduction in the surface heat loss to the atmosphere| and this acts to further stabilize the water column. We examine the importance of this reduction in surface heat loss by considering two numerical experiments that are identical except that one is run under mixed boundary conditions and the other under a flux boundary condition applied to temperature as well as salinity. In each case| the surface fluxes are diagnosed from an experiment run to equilibrium using restoring boundary conditions on both fields. This also provides the initial state for both experiments. A PHC is easily induced in the mixed boundary condition case but not in the case using flux boundary conditions. By reducing the magnitude of the heat flux but not its sip| a pool of fresh water appears at the surface| but its effect is weaker than that under mixed boundary conditions and| in particular| there is no collapse of the meridional overturning circulation. A pool of fresh water also appears in an experiment in which a small| positive heat flux is added at all latitudes| a situation of relevance to global warming. This leads to an initial cooling in a shallow layer at the surface of the polar oceans| before heating at lower latitudes leads to a collapse of this state. These experiments show that the reduction in the surface heat flux that occurs when the PHC develops under mixed boundary conditions is an essential feature of the PHC. The use of mixed boundary conditions assumes that the atmospheric state is fixed and does not respond to changes in heat flux from the ocean. If the atmosphere were allowed to adjust to changes in this heat flux| then a PHC would be less likely to occur. This has been demonstrated by coupling the ocean model to the zero-heat-capacity atmospheric model used by Schopf. This is justified| following Bretherton| because of the large horizontal scale of the sea surface temperature (SST) anomalies in the experiments. The authors were unable to induce a PHC with this model. In reality| the atmospheric boundary condition seen by the ocean lies somewhere between the two extremes of mixed boundary conditions| on the one hand| and Schopf's model on the other. We have investigated this intermediate region by conducting experiments in which SST anomalies are damped on successively shorter time scales. These show that if the damping time is reduced sufficiently| a PHC can again be induced. 3954,1993,3,4,A UK GREENHOUSE-GAS INVENTORY - ON ESTIMATING ANTHROPOGENIC AND NATURAL SOURCES AND SINKS,The Climate Change Convention requires signatory countries to calculate inventories of greenhouse-gas emissions from anthropogenic activities| and from natural sources and sinks. This paper presents estimations for the Ut(| an industrialized temperate country with intensive land-use and little natural vegetation cover. The UK's 1988 anthropogenic carbon dioxide emissions total 183 million tons (metric). When the net sequestration from soil and biomass is included in aggregate carbon dioxide emissions| this total is reduced by only 0.72%. Net emissions increase however for methane (CH4) and nitrous oxide (N2O) from the land-use sector. There is a need for a clear definition of the distinction between natural and anthropogenic sources where the capacity of the biosphere to act as a sink is limited by human intervention| In the method adopted here| distinction is made between emissions from activities not associated with biological activity| defined as anthropogenic| and exclusively from biological processes| with or without human intervention. The relative contributions of the different gases is also significantly affected by the time horizon| and hence the assumed global warming potential adopted for the analysis. 4040,1993,2,6,ABSENCE OF SCIENTIFIC BASIS,Current concerns over significant global warming are based on simple| plausible physical arguments that increasing CO2 levels will lead to some warming. Model predictions of large warming depend on projected large increases in atmospheric CO2| and mechanisms within the models which act to greatly amplify the climate response to increasing CO2. The projections depend on questionable economic| population| and energy scenarios; they also depend on clearly inadequate chemical models which serve to exaggerate the fraction of emitted CO2 remaining in the atmosphere. The amplification mechanisms (positive feedbacks) depend on what is likely to be a severe misrepresentation of the relevant physical processes: moisturization of the atmosphere and cloud formation. Recent data suggest that these processes may be acting in a manner opposite to what current models produce. Under the circumstances| the possibility of large warming| while not disproven| is also without a meaningful scientific basis. 4016,1993,2,3,AGRICULTURAL IMPACTS OF AND RESPONSES TO CLIMATE-CHANGE IN THE MISSOURI-IOWA-NEBRASKA-KANSAS (MINK) REGION,The climate of the 1930s was used as an analog of the climate that might occur in Missouri| Iowa| Nebraska and Kansas (the MINK region) as a consequence of global warming. The analog climate was imposed on the agriculture of the region under technological and economic conditions prevailing in 1984/87 and again under a scenario of conditions that might prevail in 2030. The EPIC model of Williams et al. (1984)| modified to allow consideration of the yield enhancing effects of CO2 enrichment| was used to evaluate the impacts of the analog climate on the productivity and water use of some 50 representative farm enterprises. Before farm level adjustments and adaptations to the changed climate| and absent CO2 enrichment (from 350 to 450 ppm)| production of corn| sorghum and soybeans was depressed by the analog climate in about the same percent under both current and 2030 conditions. Production of dryland wheat was unaffected. Irrigated wheat production actually increased. Farm level adjustments using low-cost currently available technologies| combined with CO2 enrichment| eliminated about 80% of the negative impact of the analog climate on 1984/87 baseline crop production. The same farm level adjustments| plus new technologies developed in response to the analog climate| when combined with CO2 enrichment| converted the negative impact on 2030 crop production to a small increase. The analog climate would have little direct effect on animal production in MINK. The effect| if any| would be by way of the impact on production of feed-grains and soybeans. Since this impact would be small after on-farm adjustments and CO2 enrichment| animal production in MINK would be little affected by the analog climate. 3983,1993,4,4,AGRICULTURE AND GLOBAL WARMING,Global warming poses a distinct threat to agricultural systems worldwide and to attempts to place farming on more sustainable foundations. The magnitude and severity of that threat is systematically understated by the use of inappropriate models of risk and economic analysis that underestimate potential costs of global warming. The author proposes that the logic underlying Pascal's wager about the existence of God| a variant of minimax strategies in game theory| may be an instructive alternative. 2688,1993,2,2,AGRICULTURE IN A GREENHOUSE WORLD,While agriculture in some temperate regions may benefit from global climate change| tropical and subtropical regions may suffer. Even where potential production will improve| the required adjustments may disrupt ecosystems and land-use patterns. Agricultural zones will shift toward high latitudes| while heat stress and increased droughts will reduce productivity in lower latitudes. On the positive side| higher CO2 may enhance photosynthesis and water-use efficiency. Future hazards include sea-level rise| insect infestation| and greater evaporation losses. Some agricultural activities augment the greenhouse effect by releasing CO2| CH4| and N2O. Understanding the potential impacts of climate change is a prerequisite to developing societal responses.
2702,1993,2,3,AGRICULTURE| FOOD AND THE ENVIRONMENT,The United Nations Conference on Environment and Development alerted the world to the hazards presumptive if the planet's natural resources of land| water| air| energy and biological organisms are not protected and utilised more conservatively. UNCED declared two urgent research priorities: global climate change and genetic diversity. Excessive use of fossil fuels and a resultant atmospheric pollution forebodes higher temperatures at the earth's surface. The consequences for agriculture are unpredictable. Alternative sources of energy are described: electric motors with high-capacity batteries and high energy fly-wheels; solar-thermal and photovoltaic systems of power generation. Global population will rise to at least 8 billion (1 billion = 10(9)) by 2025| a rate of growth demanding an annual increase of 3% in agricultural production. The principles of sustainable production in relation to land and water management| genetic diversity among crop species| and food science and technology are discussed. Among the many thousand crop genotypes in the international germ plasm banks| more is known about agronomic characters than about functional properties relevant to food processing. Transgenic modifications broaden the spectrum of pest resistance in crops| but too little is known of the nutritional implications. Biotechnological advances| demands for non-polluting waste disposal| consumer concerns for food safety| the need to provide food security for a global population changing in age and income distribution| offer exciting challenges to all food scientists and technologists.
2673,1993,2,4,AIR-POLLUTION-MEDIATED CHANGES IN ALPINE ECOSYSTEMS AND ECOTONES,Soil biological parameters (e.g.| Collembola)| soil types| soil chemical parameters (pH| humus substances)| and plant communities were studied in different ecosystems and ecotones in alpine| subalpine| and spruce forest zones in the Tatra National Park| Slovak Republic. The preliminary| selected data| based on a long-term research program| showed a high sensitivity of some alpine ecotones and ecosystems to long-distance transported acid deposits. The changes in different ecosystem parameters since 1977 were more extensive in alpine grasslands on limestone than on granite. The greatest soil pH decrease was in the plant communities Festucetum versicoloris (- 1.5 pH)| Geranio-Alchemilletum crinitae (- 1.32 pH)| and Saxifragetum perdurantis (- 1.25 pH)| which are restricted to places with snow accumulation and water runoff gullies. In these ecosystems the greatest changes occurred in the leaching of humus substances. Some formerly less abundant and rare soil animals restricted to acid bedrock became dominant in some ecosystems on limestone as well as on granite; other formerly dominant species disappeared from the entire study area (e.g.| Folsomia alpina). The aerial extent of some ecosystems changed substantially since 1977| and their surrounding ecotones moved into the space formerly occupied by one of the adjacent ecosystems. These changes are detectable by remote-sensing methods. In Central European mountains| strongly affected by global and regional industrial air pollution (e.g.| Krusne Hory| Krkonose| Beskydy)| spruce forests started to die back from higher to lower mountain elevations. The effects of air pollution on alpine and subalpine vegetation were not studied there. Strong alterations in alpine ecosystems and ecotones were detected by the author during long-term studies in the High Tatra Mountains| and I suggest that subalpine and mountain forest belts will be affected here in the near future as they were in the more polluted Central European mountains. The ecosystems and ecotones in higher alpine zones are likely to be affected earlier than the ecosystems at lower altitudes. Detection of ecosystem alteration in the alpine zone may be used for prediction of acidification processes and global change in ecosystems at lower altitudes. The consequences of global climate change are predictable by monitoring changes in the extent of some ecosystems located in discrete mountain geomorphological units (e.g.| karstic sinkholes| water runoff gullies| wind shadows| ridges exposed to wind| etc.) and ecotones among them because of their dependence on duration of snow cover| water supply| wind and frost exposure| and other abiotic and biotic factors.
4015,1993,2,4,AN ANALYSIS OF MICROCLIMATIC VARIATION IN A SUBURBAN ENVIRONMENT,An observational and modeling study of the microclimate of a suburban area| as related to the physical and biological nature of the site| is presented. The measurements and calculations are made in comparison with a nearby open agricultural location or ''control site''. The measurement program was conducted during the summer of 1981 in Davis| CA| and consisted of paired observations in which simultaneous measurements were made at a control site| located in a nearby rural area and one suburban site at a time. Results indicate that this methodology was generally successful. The various suburban sites were as often cooler than the rural site as they were warmer. In one case | a suburban site was found to be substantially cooler| averaging 7.38-degrees-C over a 5 day period| than the rural site. This special case was observed to be associated with unusually dry environmental air resulting in large evaporative cooling in the plant canopy. Comparison between the suburban temperature deficit and the physical nature of the various sites reveals that canopy height explained most of the variance of this data set. Two generally important mechanisms are hypothesized to be operating in this system: the effect of canopy size on turbulent mixing and on site shading| especially of paved areas. A simple energy balance model was applied to study the processes that control the daytime suburban temperature deficit. In particular| it is found that suburban sites can be as cool as observed when the following conditions are obtained: low-canopy humidity| large canopy size| low wind speed and high radiation load. The model simulated the overall average suburban temperature deficit of all sites for physically reasonable choices of model parameters. It is pointed out that the fact that suburban areas may be cooler than surrounding rural areas may have significance to the problem of assessing the role of the urban heat island in relation to possible global warming. 2660,1993,4,2,AN EMPIRICAL-ANALYSIS OF THE STRENGTH OF THE PHYTOPLANKTON-DIMETHYLSULFIDE-CLOUD-CLIMATE FEEDBACK CYCLE,The possible influence of the marine biogeochemical sulfur cycle on the global climate has been a topic of much recent research. Based on the hypothesis that phytoplankton could affect cloud albedo by producing dimethylsulfide| which is a precursor to aerosols and cloud condensation nuclei| and that cloud albedo could in turn affect the productivity of the phytoplankton| the presence of such a feedback cycle would have significant implications for models of global climate change. By considering available data on the relationships between individual components of the proposed feedback| an empirical model is developed of the cycle as a whole| allowing an assessment to be made of the degree to which the cycle could thermostatically regulate the climate. It is estimated that the feedback strength is about 20% (10% - 50%) of that which would be necessary to completely counteract a perturbation to the global climate| such as is anticipated due to accumulation of anthropogenic greenhouse gases.
3985,1993,3,3,AN OVERVIEW OF LARGE-SCALE CO2 DISPOSAL OPTIONS,The IEA Greenhouse Gas R&D Programme is conducting an initial 3-year study aimed at potential CO2 mitigation techniques as a response to the issue of global warming. The Programme is currently examining| on a common basis| the options available for capturing and disposing of the CO2 produced from a range of fossil fuel fired power generation plant types| each with an output of 500MW(e). The options available for disposing of large quantities of CO2 are reviewed and compared on the basis of current knowledge| and the global potential of the options estimated. Photosynthetic processes| such as forestry and biomass production| which remove CO2 from the atmosphere are also included. The long term fate of the CO2| in terms of its eventual re-entry into the atmosphere| is discussed and the disposal options chosen for further study| under the IEA Greenhouse Gas R&D Programme| are identified. 4082,1993,2,4,ANOMALOUS SEASONAL CYCLES OF DECAPOD CRUSTACEAN LARVAE IN THE NORTH-SEA PLANKTON IN AN ABNORMALLY WARM YEAR,In 1989 the seasonal cycles of most common decapod larvae in Continuous Plankton Recorder samples taken in the North Sea were significantly different from those described for 1947-1951 and for 1981-1983. In all cases where the differences were significant the larvae occurred earlier in 1989 than in previous years. Zoeae of Atelecyclus rotundatus were found in the Southern Bight in the spring. The winter of 1988-1989 was exceptionally mild with air temperatures over Great Britain 2-3-degrees-C above average and positive temperature anomalies persisted through the year. The sea surface temperatures in the North Sea were also mainly higher than usual. The events were treated as a ''natural experiment'' to examine effects of the high temperatures on seasonal cycles of decapod larval production and the implications of these effects for marine communities with reference to predicted global warming. The relationships between timing of occurrence of the larvae in the plankton and parameters of sea temperatures were generally consistent with previous results from studies of geographical variations| and possible causal mechanisms are discussed in the light of the 1989 data. 2665,1993,3,3,AQUATIC BIOMASS AND CARBON-DIOXIDE TRAPPING,The technology for growing microalgae as a renewable biomass source can be applied to the production of a diesel fuel substitute (biodiesel). Microalgae are of interest because of their high growth rates and tolerance to varying environmental conditions| and because the oils (lipids) they produce can be extracted and converted to substitute petroleum fuels. Projected global climate change provides a second important rationale for this approach. Climate change has been linked to the accumulation of excess carbon dioxide in the atmosphere. The burning of fossil fuels in power plants is the primary contributor to excess carbon dioxide. Inasmuch as the primary nutrient for microalgal growth is carbon dioxide| operation of microalgal biomass farms has emerged as a promising candidate in the search for alternative approaches to ameliorate global climate change. The production of diesel fuel by microalgae requires very large quantities of carbon dioxide as a nutrient. In areas where microalgae fuel farms operate in tandem with fossil fuel plants to scrub carbon dioxide from flue gases| the release of carbon dioxide could be significantly reduced. If the microalgae are used to produce fuel| a mass culture facility reduces by approximately 50% the carbon dioxide emissions from the power plant per million Btu delivered. For example| although coal is ordinarily considered to be the most polluting fossil fuel on the basis of carbon dioxide emitted per amount of energy produced| the incorporation of microalgal ponds with a coal-fired plant would make this fossil fuel less polluting than existing oil- and natural-gas-fired plants. Similar advantages can be achieved for oil- and gas-fired plants. If commodity chemicals are produced from algae instead of fuels| the net carbon dioxide reduction is significantly greater. Commodity chemicals can be used to produce goods with long-term uses such as building materials. Such uses would result in the sequestering of carbon dioxide for long periods. Of the photosynthetic organisms| microalgae are the most productive carbon dioxide users and can fix greater amounts of carbon dioxide per land area than higher plants. Also| maximum productivities of higher plants and trees are restricted to areas with prime soil| water| and climate (primarily the tropics). Plant leaves exist in an aerial environment and are subject to large evaporative moisture losses| which directly inhibit the process of photosynthesis (carbon dioxide uptake). Microalgae in mass culture are not subject to such photosynthetic inhibition because the water content of the culture can be controlled by proper engineering| and saline water can be used if necessary. This difference is the basis for the several-fold higher carbon dioxide absorption capacity of microalgae compared to plants. Initial application of this technology is envisioned for the Desert Southwest of the United States because this area provides high solar radiation and offers flat land that has few competing uses (hence low land costs). Also| there are large saline aquifers with few| competing uses in the region. These could provide a suitable| low-cost culture| medium for the growth of many species of microalgae.
2695,1993,3,3,AQUATIC BIOMASS RESOURCES AND CARBON-DIOXIDE TRAPPING,Intensively managed microalgal production facilities are capable of fixing several-fold more carbon dioxide per unit area than trees or crops. Although CO2 is still released when fuels derived from algal biomass are burned| integration of microalgal farms for flue gas capture approximately doubles the amount of energy produced per unit of CO2 released. Materials derived from microalgal biomass also can be used for other long-term uses| serving to sequester CO2. Flue gas has the potential to provide sufficient quantities of CO2 for such large-scale microalgae farms. Viewing microalgae farms as a means to reduce the effects of a greenhouse gas (carbon dioxide| CO2) changes the view of the economics of the process. Instead of requiring that microalgae-derived fuel be cost competitive with fossil fuels| the process economics must be compared with those of other technologies proposed to deal with the problem of CO2 pollution. However| development of alternative| environmentally safer energy production technologies will benefit society whether or not global climate change actually occurs. Microalgal biomass production has great potential to contribute to world energy supplies| and to control CO2 emissions as the demand for energy increases. This technology makes productive use of arid and semi-arid lands and highly saline water| resources that are not suitable for agriculture and other biomass technologies.
4079,1993,2,4,ARTHROPODS AS DISEASE VECTORS IN A CHANGING ENVIRONMENT,Arthropod vectors need to acquire energy| moisture| hosts and shelter from their environment. Changing human populations and industrialization affect almost every aspect of the environment. In particular| the prospects of climatic warming| urbanization and vegetation changes have the potential to materially affect global patterns of vector-borne diseases. Global warming will enable the expansion of the geographical distributions of vectors. The population dynamics of vectors will change in response to extended seasons suitable for development followed by less severe winters. The incidence of epidemics is likely to change in response to an expected disproportionate increase in the frequency of extreme climatic events. The impact of such changes on each of the major vector-borne diseases is reviewed and projections are made on the likely global areas at risk from spread of disease vectors. Research needs are identified and response strategies are suggested in the context of the ever-increasing impact of human populations and industrial activity on the environment. 2670,1993,3,3,ASSESSING THE EFFECTIVENESS OF MARINE CO2 DISPOSAL,We consider the relative effectiveness of systems for collection and marine disposal Of CO2 from fossil fuel fired power plants using comparisons of the trend with time Of CO2 concentration in the atmosphere from systems with and without marine disposal. The retention time for CO2 increases rapidly with depth of disposal| from a few years in the mixed layer up to several centuries as the depth increases beyond 1000 m| suggesting that deep oceans should be considered as potential storage sites for CO2. However| CO2 collection and disposal consumes energy and produces extra CO2. We show that some of this extra this CO2 reaches the atmosphere| so that atmospheric concentrations from systems with marine disposal ultimately exceed those from systems without controls. In some circumstances they do so rapidly| making marine disposal less favorable than direct atmospheric release. Global Warming Potential can be used to compare systems. This highlights the difficult issues involved in determining what time scales are important in considering options to reduce concerns about global warming.
3974,1993,4,3,ASSESSMENT OF THE ATMOSPHERIC HAZARDS AND RISKS OF NEW CHEMICALS - PROCEDURES TO ESTIMATE HAZARD POTENTIALS,Before introduction new chemical substances are evaluated on their potential hazards and risks. Concerning the assessment of atmospheric hazards and risks the direct effects caused by exposure to the new chemicals and indirect effect caused by deposition to soil and surface water are accounted for in assessment systems. However| the potential impact of new chemicals on atmospheric processes is generally not included. In this paper procedures to estimate ''hazard potentials'' to quantify the potential risk of a new substance in atmosphere-related environmental problems are proposed and discussed. In particular| hazard potentials for the following topics are defined: global warming; ozone depletion; photochemical smog formation; acidification and eutrophication. Based on these ''hazard potentials'' atmospheric hazards and risks can be assessed. 4024,1993,3,3,AUTOMOTIVE EMISSIONS IN DEVELOPING-COUNTRIES - RELATIVE IMPLICATIONS FOR GLOBAL WARMING| ACIDIFICATION AND URBAN AIR-QUALITY,This paper attempts to assess the magnitude and scope of automotive pollutant emissions in developing countries and their role in global warming| regional scale air pollution and urban air quality. Greenhouse-gas emissions (CO2 and CFCs) from motor vehicles in developing countries contribute less than 3% to the global greenhouse effect| compared to a 9 to 12% contribution from motor vehicles in OECD countries and Eastern Europe. The share of OECD countries in conventional pollutant emissions from motor vehicles exceeds the combined contribution of all developing countries by a factor of three to five. Acid deposition from motor vehicle emissions does not currently appear to be a problem in developing countries. The incidence of regional scale ozone is not known but could be potentially significant downstream from large urban centers. There is a need for more systematic monitoring and evaluation of acid deposition and regional ozone concentrations in developing countries. Urban air quality is the prime casualty of motorization in developing countries. The air pollution problem will intensify in developing countries with increasing urbanization and the rapid pace of motorization. Urban concentrations of carbon monoxide| airborne lead| particulate matter and sulfur oxides in many developing countries already exceed the levels in industrialized countries. Motor vehicles emit 30% to 85% of all man-made air pollutants in the large urban areas in developing countries| depending on the level of motorization. Without effective measures to control pollutant emissions| some 300 to 500 million city dwellers in developing countries will become exposed to unhealthy and dangerous levels of air pollution from motor vehicles by the year 2000. 4005,1993,2,4,BASIC TENDENCIES IN CHANGES OF THE EARTHS VEGETATION IN RELATION TO GLOBAL WARMING OF THE CLIMATE,An analysis is presented of current approaches to prediction of possible changes of vegetation in relation to existing tendencies in global warning of the climate. Preference is accorded to the structural-functional approach in plant ecology based on study of the dissemination of plants with different types of photosynthesis (C3| C4| and CAM) and variants (biochemical and structural) of the C4 syndrome in relation to climatic factors. The possibility of realization of such an approach is demonstrated on the example of the latitude| altitude| and edaphic distribution of species of the families Poaceae and Chenopodiaceae. 4049,1993,4,5,BENIGN GREENHOUSE,Several lines of evidence are emerging that suggest that the ''popular vision'' of global warming-major agricultural damage| disastrous sea-level rise| and ecological disequilibrium-is flawed. The popular vision is driven primarily by the prospect of enhanced daytime warming| particularly in summer What has been observed is a warming that is beneath the projections that support the popular vision| and a warming that has occurred virtually all during the night in the Northern Hemisphere. In the Southern Hemisphere there is also evidence of disproportionate night warming. Several sources of data indicate that this night warming has been caused by an increase in cloudiness that could be a consequence of the greenhouse enhancement itself. The results of the night warming-longer growing seasons| little change in moisture stress| and a possible increase in ice volume-are opposite to the popular vision of climatic change.
4046,1993,5,4,BIPOLAR MOLLUSKS AND THEIR EVOLUTIONARY IMPLICATIONS,The phenomenon of bipolarity| one of the major disjunct distribution patterns on the face of the earth| has been investigated repeatedly since the mid-nineteenth century. Running through the many hypotheses that have been put forward to account for its occurrence| it is possible to detect two persistent themes: it is usually interpreted within a dispersal framework| and it is generally believed to be of comparatively recent origin. To many authors| the phenomenon is intimately linked to the Plio-Pleistocene glaciations. Recent palaeontological investigations have established that bipolarity can now be traced back to at least the Early Jurassic period (i.e. 200 m.y.a.). Here it is well marked in the Pliensbachian stage by a variety of pectinacean bivalve taxa. Further bivalves indicate probable Middle Jurassic examples| but the phenomenon is more clearly seen in the Late Jurassic| especially in the Tithonian stage. At this time| inoceramid| buchiid and oxytomid bivalve occurrences at northern hemisphere localities such as arctic Canada| N.W. Europe| Siberia| N.E. USSR and Japan can be matched with those in southern South America| Antarctica and Australasia. A striking Early Cretaceous (Aptian-Albian) bipolar pattern for the oxytomid Aucellina may be complemented by several infaunal bivalves| brachiopods and at least one gastropod. There is strong circumstantial evidence to suggest that bipolar molluscs continued to develop through the Cenozoic era. Such is the level of generic and subfamilial differentiation within certain living forms as to suggest that they must be the product of a considerable evolutionary history. It is likely that present-day distribution patterns of prosobranch gastropod groups such as the whelks (Buccinidae)| together with certain fissurellids| littorinids| naticids and turrids| can be related to a late Paleogene-early Neogene phase of bipolarity. Many amphitropical taxa| in both the marine and terrestrial realms| have probable late Neogene-Pleistocene origins. It is possible to set the Jurassic and Cretaceous examples of bipolarity within a largely vicariant framework based upon the disintegration of the Pangean supercontinent. In this way the widespread ranges of putative Triassic ancestors were disrupted by tectonic processes in low latitude regions| although it should be emphasized that major climatic and oceanographic changes were almost certainly involved too. Similarly| it is possible to view late Paleogene-early Neogene bipolarity as a vicariant event| but this time with climatic change identified as the single most important agent. Widespread or cosmopolitan distributions are held to have formed during global cool phases (such as the late Eocene-early Miocene) only to be disrupted by global warming (such as in the late early Miocene). It is even possible to view Plio-Pleistocene patterns as| at least in part| the products of vicariant events caused by rapid temperature and sea level shifts. Clearly| there is an urgent need here for more critical taxonomic data to test these various hypotheses. Phylogenetic studies of groups such as the Mesozoic bivalve superfamily Monotoidea and the Cenozoic Buccinidae| in particular| should constitute future rigorous tests. In so doing| they should also provide much useful information on the relative roles of dispersal and vicariance in promoting global disjunction in marine faunas. Repeated formation of bipolar patterns through geological time may have had important implications for modes of speciation and phenomena such as the origin of taxonomic diversity gradients. 4068,1993,3,3,CAN FUEL-BASED ENERGY-PRODUCTION MEET THE CHALLENGE OF FIGHTING GLOBAL WARMING - A CHANCE FOR BIOMASS AND COGENERATION,In long-term energy strategies| one of the most crucial challenges will be fighting global warming. This requires considerable structural changes in energy production. There is clear evidence that the increase in atmospheric carbon dioxide causes the 'greenhouse effect| while opinions differ about its seriousness. However| it is the first real threat caused by mankind to his own life expectancy. Finland - as other European countries - has engaged to freeze and later also to reduce its CO2 emissions. Can energy production be based essentially on fossil fuels or are nuclear power and renewable energy sources the only energy alternatives in the future ? 4042,1993,4,3,CARBON-DIOXIDE AND CLIMATE - THE IMPACT OF CLOUD PARAMETERIZATION,The importance of the representation of cloud in a general circulation model is investigated by utilizing four different parameterization schemes for layer cloud in a low-resolution version of the general CirCulation model at the Hadley Centre for Climate Prediction and Research at the United Kingdom Meteorological Office. The performance of each version of the model in terms of cloud and radiation is assessed in relation to satellite data from the Earth Radiation Budget Experiment (ERBE). Schemes that include a prognostic cloud water variable show some improvement on those with relative humidity-dependent cloud| but all still show marked differences from the ERBE data. The sensitivity of each of the versions of the model to a doubling of atmospheric CO2 is investigated. Midlevel and lower-level clouds decrease when cloud is dependent on relative humidity| and this constitutes a strong positive feedback. When interactive cloud water is included| however| this effect is almost entirely compensated for by a negative feedback from the change of phase of cloud water from ice to water. Additional negative feedbacks are found when interactive radiative properties of cloud are included and these lead to an overall negative cloud feedback. The global warming produced with the four models then ranges from 5.4-degrees with a relative humidity scheme to 1.9-degrees-C with interactive cloud water and radiative properties. Improving the treatment of ice cloud based on observations increases the model's sensitivity slightly to 2.1-degrees-C. Using an energy balance model| it is estimated that the climate sensitivity using the relative humidity scheme along with the negative feedback from cloud radiative properties would be 2.8-degrees-C. Thus| 2.8-degrees-2.1-degrees-C appears to be a better estimate of the range of equilibrium response to a doubling of CO2. 4080,1993,3,3,CHEMICAL POLLUTION OF THE ENVIRONMENT - PAST| PRESENT AND FUTURE,In an era of 'global environmental change' people are concerned about emissions of CO2| CH4| N2O and chlorofluorocarbons (CFCs) to the atmosphere because of their direct impact on global warming and their stratospheric ozone-depleting effects. Unprecedented efforts have been made to reduce the global emissions of CFCs. Major industries| which are competing within the modern global economy| have recognized the importance of maintaining a 'green' perspective. Future operations will be designed to reduce the direct emissions of chemical by-products to air| water and soil| and to recycle and to reuse critical solvents such as water. 'Star Wars' technologies for the rapid| economical and effective elimination of industrial and domestic wastes will be developed and employed on a large scale. Advanced technologies for the control and monitoring of chemical pollutants on regional and global scales will be developed and implemented. Satellite-based instruments will be able to detect| to quantify| and to monitor a wide range of chemical pollutants. Our understanding of the fate and consequences of chemicals in the environment will increase dramatically such that we shall be able to predict the environmental| ecological and biochemical consequences of novel synthetic molecules with much greater precision. 4073,1993,2,3,CLIMATE EFFECTS OF ATMOSPHERIC METHANE,We discuss the role of the concentration increase of atmospheric CH4 (currently almost-equal-to 0.8% yr-1) in climate change| including effects through chemical feedbacks| notably through formation of 03 and stratospheric H2O| and reduction of OH levels| which increases the lifetime of CH4 . We present results of simulations with a coupled 1-D radiative-convective model| which includes chemical and radiative processes in the troposphere and stratosphere| and which treats both hemispheres separately. Our results deviate appreciably from those reported in earlier studies- the reason for this is discussed in detail The current climate forcing by CH4 (excluding indirect chemical effects) is 26 times that Of CO2 (calculated on a mole CO2/Mole CH4 basis). A recently introduced quantity to express the time integrated effect of CH4 relative to that of CO2 over a given time interval is the global warming potential (GWP). We assess that the GWP of CH4| including chemical feedbacks| over a 10 year integration period is 26.9 (Mole CO2/mole CH4)| decreasing to 7.5 for a time horizon of 100 years. Considering that the use of fossil fuels is associated with emissions of both CO2 and CH4| we evaluated the climatic consequences of switching from coal or oil to natural gas. We conclude that| if the fractional gas leakage from production and distribution of natural gas is below 4.3 - 5.7%| a switch from coal to natural gas as energy source would reduce the rate of climate warming. The use of gas would be preferable over the use of oil (from a climate point of view)| if the fractional gas leakage is less than 2.4 - 2.9%. The ranges express uncertainties in CH4 releases from coal and oil production. 3997,1993,5,4,CLIMATE INSTABILITY DURING THE LAST INTERGLACIAL PERIOD RECORDED IN THE GRIP ICE CORE,Isotope and chemical analyses of the GRIP ice core from Summit| central Greenland| reveal that climate in Greenland during the last interglacial period was characterized by a series of severe cold periods| which began extremely rapidly and lasted from decades to centuries. As the last interglacial seems to have been slightly warmer than the present one| its unstable climate raises questions about the effects of future global warming. 3948,1993,2,4,CLIMATE-CHANGE AND THE SHORT-TERM IMPACT OF FERAL HOUSE MICE AT THE SUB-ANTARCTIC PRINCE-EDWARD-ISLANDS,At the Prince Edward Islands| temperatures have increased by approximately 1 degrees C over the past 40 years| accompanied by a decline in precipitation. This ha's led to a reduction in the peat moisture content of mires and higher growing season ''warmth''. The temperature- and moisture-sensitive sedge| Uncinia compacta R. Pr. (Cyperaceae)| has consequently increased its aerial cover on Prince Edward Island| but harvesting of seeds by feral house mice (up to 100% removed) has prevented this from happening on Marion Island. Such extensive use of resources suggests that prey switching may be taking place at Marion Island. Seat analyses revealed that mice are not only eating ectemnorhinine weevils to a greater extent than found in previous studies of populations at Marion Island| but that they also prefer larger weevils (+/- 6 mm). A decrease in body size of preferred weevil prey species [Bothrometopus randi Jeannel and Ectemnorhinus similis C.O. Waterhouse (Coleoptera: Curculionidae)] has taken place on Marion Island (1986-1992)| but not on Prince Edward Island. This appears to be a result of increased predation on weevils. In addition| adults of the prey species| E. similis are relatively more abundant on Prince Edward Island than adults of the smaller congener E. marioni Jeannel| and could not be found on Marion Island in the late austral summer of 1991. These results not only provide support for previous hypotheses of the effect of global warming on mouse-plant-invertebrate interactions on the Prince Edward Islands| but also provide limited evidence for the first recorded case of predator-mediated speciation. They also show that the interaction of human-induced changes operating at different scales may have profound consequences for local systems. 2671,1993,2,3,CLIMATE-CHANGE AND WATER-RESOURCE AVAILABILITY - AN IMPACT ASSESSMENT FOR BOMBAY AND MADRAS| INDIA,Global climate change associated with rising atmospheric concentrations of greenhouse gases may alter regional temperature and precipitation patterns. Such changes could threaten the availability of water resources for rapidly growing Third World cities| many of which are already experiencing severe water supply deficiencies. This paper investigates the potential impacts of climate change on water resource availability for two Indian cities| Bombay and Madras. The paper begins by discussing future trends for population growth and water demand in each city. Next| using climate change scenarios based on three general circulation models (GCMs)| the paper assesses how climate change may affect water availability in the two urban regions. The assessment is conducted through the use of a monthly dryness index measuring potential evapotranspiration and precipitation. For each region| the dryness index under ''normal'' climatic conditions is compared with indexes created using GCM scenarios. The results of this assessment indicate that| unless large increases in regional precipitation accompany climate warming| higher rates of evapotranspiration will mean reduced water availability for both cities. The paper concludes by discussing some implications for water management in Third World cities.
3984,1993,4,2,CO2 AND CLIMATIC-CHANGE - AN OVERVIEW OF THE SCIENCE,International policy measures to deal with the enhanced greenhouse effect am being debated on a scientific basis which is still uncertain. The Intergovernmental Panel on Climate Change (IPCC) has produced a major scientific assessment of climatic change. They concluded that| despite uncertainties| the model simulations of a warming due to increased concentrations of greenhouse gases am broadly consistent with observations of global temperature changes. Carbon dioxide is the most important greenhouse gas from human activities. Increases in CO2 concentrations in the atmosphere contribute over half of the enhanced greenhouse effect| the rest being mainly due to increases in halocarbons and methane. The total effect of greenhouse gas emissions depends on their lifetimes in the atmosphere. The global warming potential of other greenhouse gases is expressed relative to that of CO2. However| the lifetime Of CO2 in the atmosphere is complicated by uptake into the many carbon storage sinks of the global carbon cycle. Knowledge of the global carbon cycle is incomplete| the sources exceeding the sum of known sinks. Reductions in the concentration of CO2 in the atmosphere could be achieved by reducing the emissions or enlarging the sinks. What is achieved in future will depend to a large extent on a mom detailed understanding of carbon storage mechanisms. 4052,1993,3,3,CO2 EMISSIONS CONTROL - COMPARING POLICY INSTRUMENTS,We use a global model to compare the economic performance of three policy instruments for controlling CO2 emissions -period specific emission limits (limit policy)| period specific taxes (tax policy)| and a cumulative emissions limit (cumulative limit policy). With known costs and benefits of control| tax and limit policies are equivalent| and either is better than a cumulative limit policy. With uncertain benefits of emission reduction| tax and limit policies are equivalent. However| with uncertain costs of emission reduction| a tax policy may be better. A cumulative limit policy may occasionally perform well under uncertainty| but this is not generally the case. 4077,1993,3,3,COMBATING GLOBAL WARMING - REDUCING CO2 EMISSIONS FROM COAL-FIRED POWER-PLANT,The threat of global warming is sufficient to warrant 'least regrets' measures to reduce emissions of greenhouse gases| in particular through increased efficiency in energy production and use. British Coal has set up a programme to contribute to the international responses to the threat. It is concentrating on investigating options for removing carbon dioxide from fossil-fuelled power plants in case expensive fallback options become necessary. Screening of the options commenced with flowsheeting studies which estimated the thermal efficiency of a number of process schemes. These screening studies concluded that carbon dioxide (CO2) control could be retrofitted to existing coal-fired power stations| but that the new generation of gasification-based systems is more promising. CO2 separation could be more easily integrated into advanced power plants as they operate at high pressure| resulting in increased CO2 partial pressure which reduces the energy penalty associated with the separation. The CO2 would need to be exported as a liquid stream for storage in exhausted oil or gas fields Costs of such power plants and CO2 disposal options have been developed. These studies suggest that| using proven technology| the cost of electricity would rise by about 42 per cent. If novel gas separation systems based on membranes can be developed| the increase in electricity cost could be limited to around 34 per cent. This paper discusses the options and presents the results of costing studies| 3971,1993,3,4,COMPARISON OF ENVIRONMENTAL IMPACTS OF ELECTRICITY FROM DIFFERENT SOURCES,There is a variety of techniques for comparing the environmental impacts of electricity from different sources. Only monetary valuation of the impacts offers the prospect of providing comparison on a single baseline. Unfortunately| practical and methodological problems generally prevent accurate valuation. For fossil fuel electricity generation the major environmental externalities result from acid deposition| tropospheric ozone and global warming. For nuclear power the main issues are major reactor accidents and long-term waste disposal. Some broad estimates of environmental externalities (in p/kWh) are given from each| based on available scientific evidence and valuation studies. The uncertainties and methodological problems associated with valuation prevent any reliable statement about the relative magnitudes of externalities resulting from fossil and nuclear generating options. In both cases| some of the impacts are incompatible with stricter interpretations of sustainability. The important environmental impacts of most renewable electricity generating options concern human amenity. With some exceptions| where areas of more than local significance for ecology or recreation are concerned| the monetary values of the impacts will be small. For most electricity conservation technologies| the externalities are negligible. Energy conservation and renewable electricity supply will therefore form key components of a sustainable energy system. 4039,1993,2,2,DEGREES OF CERTAINTY,Debate in the media over global warming often mixes what is well known with what is speculative| thereby leading to an artificially confusing impression that scientists share no consensus of the probable magnitude| timing| and potential seriousness of the environmental and societal consequences of the documented and well-understood buildup of various greenhouse-enhancing gases in the atmosphere. Indeed| widespread concern exists over the plausibility of temperature increases of 1 to 5-degrees-C in the 21 st century| and that the mid to upper part of that range could imply dramatic restructuring of ecosystems or communities. I discuss the difficulty in interpreting the 0.5 +/- 0.2-degrees-C 20th century warming trend as ''proof'' of greenhouse-gas-induced global warming in light of possible climatic-change causal factors such as industrial aerosols| natural fluctuations| or changes in solar output. How to act is controversial| and economic model results showing potential abatement costs of carbon taxes are discussed 4032,1993,2,4,DIFFERENTIAL GROWTH-RESPONSES OF CASSIOPE-TETRAGONA| AN ARCTIC DWARF-SHRUB| TO ENVIRONMENTAL PERTURBATIONS AMONG 3 CONTRASTING HIGH SITES AND SUB-ARCTIC SITES,Three populations of Cassiope tetragona (Ericaceae) were subjected to in situ environmental perturbations simulating predictions of global warming. The populations were selected to represent different parts of the range of the species| one growing in a high arctic coastal heath at Ny-Alesund (Svalbard| northern part of the species' range)| one at a subarctic fellfield at 1150 m a.s.l. at Abisko| Swedish Lapland| and one in a subarctic tree-line heath at 450 m a.s.l. at Abisko| southern part of the species' range. The manipulations included nutrient addition| shading and two levels of temperature enhancement using passive greenhouses. The micrometeorological effects of the shading treatment was similar to that of a mountain birch canopy and the temperature enhancement treatments had the desired effect to increase the average air temperature by 2-4-degrees-C. Greenhouses which had a gap between the soil and the greenhouse plastic were particularly successful in creating the desired climatic perturbation without causing extreme maximum temperatures or other unwanted side-effects. The environmental manipulations caused strikingly different responses in the vegetative growth pattern of main shoots of C. tetragona among the three populations: at the subarctic tree-line heath| nutrient addition caused a substantial increase in growth| whereas it was the temperature enhancement treatments that caused increases| although smaller| at the subarctic fellfield and the high arctic heath sites. At the high arctic site| we also found growth reduced in response to shading| but at the subarctic sites| and particularly at the tree-line heath site| shading caused a marked etiolation of the shoots. Hence| different factors seem to produce very different responses in the vegetative growth of C. tetragona in different parts of its geographical range. We conclude that competition for nutrients and light are the main limiting factors for the growth of Cassiope tetragona near the lower distributional limit (LODIL) of the species| but that temperature is the main limiting factor in the northern parts of its range| and at high altitudes in the southern parts of its range. We also suggest that the direct effect of predicted future climatic warming on the growth of Cassiope tetragona will increase towards the north| whereas a possible indirect effect of increasing nutrient availability following a temperature increase will be the main effect in the southern and lower parts of its range. These responses could| however| be modified by shading from other species responding to environmental change by increased growth. 3957,1993,4,2,DOES FOSSIL-FUEL COMBUSTION LEAD TO GLOBAL WARMING,Tropospheric sulfate aerosols produced by atmospheric oxidation of SO2 emitted from fossil fuel combustion scatter solar radiation and enhance the reflectivity of clouds. Both effects decrease the absorption of solar radiation by the earth-atmosphere system. This cooling influence tends to offset the warming influence resulting from increased absorption of terrestrial infrared radiation by increased atmospheric concentrations of CO2. The sulfate forcing is estimated to be offsetting 70% of the forcing by CO2 derived from fossil fuel combustion| although the uncertainty of this estimate is quite large-range 28 to 140%| the latter figure indicating that the present combined forcing is net cooling. Because of the vastly different atmospheric residence times of sulfate aerosol (about a week) and CO2 (about 100 years)| the cooling influence of sulfate aerosol is exerted immediately| whereas most of the warming influence of CO2 is exerted over more than 100 years. Consequently the total forcing integrated over the entire time the materials reside in the atmosphere is net warming| with the total CO2 forcing estimated to exceed the sulfate forcing by a factor of 4 (uncertainty range 2 to more than 10). The present situation in which the forcing by sulfate is comparable to that; by CO2 is shown to be a consequence of the steeply increasing rates of emissions over the industrial era. 4061,1993,4,4,DOES RECENT GLOBAL WARMING SUGGEST AN ENHANCED GREENHOUSE-EFFECT,Considerable controversy has been generated by the observation that the Earth's climate has warmed over the last century. Public policy decisions hinge on the question of whether this trend is natural climate variability or the result of the increase in atmospheric concentrations of greenhouse gases. The strength of the enhanced greenhouse effect depends| in large part| on the uncertain value of climate sensitivity. In this paper climate sensitivity is estimated from the global temperature record by assuming models for greenhouse forcing| climate response to forcing| and climate variability. We find optimal estimates of climate sensitivity are remarkably insensitive to assumptions| at least for forcing excluding the effect of aerosols| and these values are considerably less than most predictions arising from General Circulation Models (GCM's). It is| however| the statistical significance of these estimates that is sensitive to assumptions about climate variability. Assuming climate variability with a time scale of a decade or less| climate sensitivity is estimated to be significantly greater than zero| but also significantly lower than that predicted by GCM's. Climate variability with a century time scale is consistent with both the recent temperature record and the pre-instrumental record for the last millenium; if this type of variability is assumed| the estimate of climate sensitivity has a confidence band wide enough to encompass both zero and typical values obtained by GCM's. With century time-scale variability it will be several decades before confident estimates can be made. 2679,1993,2,3,DOWNSCALING OF GLOBAL CLIMATE-CHANGE ESTIMATES TO REGIONAL SCALES - AN APPLICATION TO IBERIAN RAINFALL IN WINTERTIME,A statistical strategy to deduct regional-scale features from climate general circulation model (GCM) simulations has been designed and tested. The main idea is to interrelate the characteristic patterns of observed simultaneous variations of regional climate parameters and of large-scale atmospheric flow using the canonical correlation technique. The large-scale North Atlantic sea level pressure (SLP) is related to the regional| variable| winter (DJF) mean Iberian Peninsula rainfall. The skill of the resulting statistical model is shown by reproducing| to a good approximation| the winter mean Iberian rainfall from 1900 to present from the observed North Atlantic mean SLP distributions. It is shown that this observed relationship between these two variables is not well reproduced in the output of a general circulation model (GCM). The implications for Iberian rainfall changes as the response to increasing atmospheric greenhouse-gas concentrations simulated by two GCM experiments are examined with the proposed statistical model. In an instantaneous '' 2 CO2'' doubling experiment| using the simulated change of the mean North Atlantic SLP field to predict Iberian rainfall yields| there is an insignificant increase of area-averaged rainfall of 1 mm/month| with maximum values of 4 mm/month in the northwest of the peninsula. In contrast| for the four GCM grid points representing the Iberian Peninsula| the change is - 10 mm/ month| with a minimum of - 19 mm/ month in the southwest. In the second experiment| with the IPCC scenario A (''business as usual'') increase of CO2| the statistical-model results partially differ from the directly simulated rainfall changes: in the experimental range of 100 years| the area-averaged rainfall decreases by 7 mm/month (statistical model)| and by 9 mm/month (GCM); at the same time the amplitude of the interdecadal variability is quite different.
3962,1993,2,4,EFFECTS OF CYCLONE WAVES ON MASSIVE CORAL ASSEMBLAGES ON THE GREAT-BARRIER-REEF - METEOROLOGY| HYDRODYNAMICS AND DEMOGRAPHY,Cyclone waves directly affect the density| structure and local distribution of coral assemblages by acting as agents of mortality and colony transport. Using the meteorological record| hydrodynamic formulations and risk analysis| we predict some demographic consequences of cyclones for massive corals growing in different regions of the Great Barrier Reef. Analysis of shear| compression and tension forces generated by waves indicate that corals firmly attached to solid substratum| even if only over a small proportion of their base| can resist all waves| regardless of colony size or shape| cyclone intensity or region. Waves are thus directly important as controls on colony-size frequency distributions only for weakly attached or unattached colonies. At 3 m depth| these colonies have a higher probability of escaping dislodgement in their first 10 years of life| the further north or south they are from 21-degrees-S| which is the latitude where severe cyclones are most frequent. At 21-degrees S| corals at depths as great as 12 m are exposed to the greatest likelihood of dislodgement. Possible implications of predicted increased storminess associated with global warming are briefly discussed. 2698,1993,3,3,EFFECTS OF INTENSIFICATION OF AGRICULTURAL PRACTICES ON EMISSION OF GREENHOUSE GASES,Poor quality diets of ruminant farm animals in developing countries lead to relatively large emissions of methane (a gas implicated in global climate change) per unit of useful animal product. Production of high quality feed requires intensive agronomic practices that result in increased emission of carbon dioxide and nitrous oxide| which also contribute to global climate change. Focusing on India| we estimate that improved diets could reduce by one-third greenhouse gas production (expressed as CO2 equivalents) per kg of milk. On the other hand| replacement of bullocks with tractors is projected to result in a greater than two-fold increase in CO2 equivalents.
2703,1993,3,3,ENERGY AND CARBON EMISSIONS - SUB-SAHARAN AFRICAN PERSPECTIVE,This paper illustrates the importance of the full involvement of sub-Saharan African countries in the international debate on global climate change despite the relatively minor contribution these nations make to worldwide emissions of greenhouse gases. The paper suggests policies that will allow these African nations to support the growth in energy services required to foster economic development through the use of less carbon-intensive technologies. Such an energy strategy would raise the quality of life of the sub-Saharan African people| and simultaneously restrain the growth of energy-related carbon emissions. Given the necessary infrastructure and political commitment| these countries can overcome the barriers that could prevent the successful implementation of these policies without sacrificing their developmental goals.
4067,1993,3,4,ENERGY AND ENVIRONMENTAL-MANAGEMENT INFORMATION-SYSTEMS,The threat of global warming| environmental instability and the possible use of green or carbon taxes on fossil fuels has increased the need for energy efficiency. Energy Conservation is now recognised as one of the easiest and most cost-effective ways of limiting or reducing CO2 emissions. Large UK companies are now assessing how much CO2 they dissipate to the environment and reviewing strategies to reduce this either in response to consumer demand or as a corporate policy decision. Computer-based information systems already exist to monitor and report on fluctuations in energy consumption. These are called Monitoring and Targeting (M & T) systems. This paper explains what M & T systems are and how they are being extended to cover reporting on corporate fuel-based CO2 emissions to help provide an integrated energy and environmental-management information system. 2693,1993,2,4,ENERGY-BALANCE COMPARISON OF SORGHUM AND SUNFLOWER,An understanding of the energy exchange processes at the surface of the earth is necessary for studies of global climate change. If the climate becomes drier| as is predicted for northern mid-latitudes| it is important to know how major agricultural crops will play a role in the budget of heat and moisture. Thus. the energy balance components of sorghum [Sorghum bicolor (L.) Moench.] and sunflower (Helianthus annuus L.)| two drought-resistant crops grown in the areas where summertime drying is forecasted. were compared. Soil water content and evapotranspiration (ET) rates also were determined. Net radiation was measured with net radiometers. Soil heat flux was analyzed with heat flux plates and thermocouples. The Bowen ratio method was used to determine sensible and latent heat fluxes. Sunflower had a higher evapotranspiration rate and depleted more water from the soil than sorghum. Soil heat flux into the soil during the daytime was greater for sorghum than sunflower| which was probably the result of the more erect leaves of sorghum. Nocturnal net radiation loss from the sorghum crop was greater than that from the sunflower crop| perhaps because more heat was stored in the soil under the sorghum crop. But daytime net radiation values were similar for the two crops. The data indicated that models of climate change must differentiate nighttime net radiation of agricultural crops. Sensible heat flux was not always less (or greater) for sorghum compared to sunflower. Sunflower had greater daytime values for latent heat flux. reflecting its greater depletion of water from the soil. Evapotranspiration rates determined by the energy balance method agreed relatively well with those found by the water balance method. For example| on 8 July (43 days after planting)| the ET rates found by the energy-balance and water-balance methods were 4.6 vs. 5.5 mm day for sunflower| respectively: for sorghum| these values were 4.0 vs. 3.5 mm day| respectively. If the climate does become drier. the lower soil water use and lower latent heat flux of sorghum compared to sunflower suggest that sorghum will be better adapted to the climate change.
4090,1993,3,2,ENVIRONMENTAL AND ECONOMIC-IMPLICATIONS OF SMALL-SCALE CHP,This paper discusses the possible environmental and economic implications of small-scale combined heat and power (CHP) in the UK. The technology is based on internal combustion engines running on natural gas. Electricity is generated with high efficiency from a fuel that has the lowest carbon to energy content of the fossil fuels. Furthermore| this form of CHP has the potential to be applied very widely. Viable installations could range from 40 kW(e) in small commercial buildings to over 50 MW(e) on large industrial sites. Small-scale CHP therefore offers great scope for reducing emissions of CO2| a major contributor to global warming. 4083,1993,3,4,ENVIRONMENTAL IMPACTS OF ELECTRICITY GENERATED BY DEVELOPING-COUNTRIES - ISSUES| PRIORITIES AND CARBON-DIOXIDE EMISSIONS,Owing to a very rapid growth in electricity generation in developing countries (DCs)| the environmental impacts associated with it are likely to increase strikingly. Whereas in the past DCs have not given these environmental issues high priority| this may change in the future because of both internal and external political pressures. It may perhaps also change through a growing recognition of the dangers of not pursuing development pathways that are sustainable over the long-term. There are significant differences between DCs and industrialised countries (ICs) in their attitudes towards appropriate| affordable policy responses to the threat of global warming. The paper begins by examining how and why the environmental issues associated with DC electricity generation are becoming increasingly pressing| both for DCs and for ICs. The issues are classified into categories. There is then a detailed discussion of greenhouse gas scenarios and the possible roles that may be played by DCs in the growth and limitation of carbon dioxide emissions. The paper notes the difficulties of reaching workable agreements on global greenhouse gas limitations that include the DCs. 4085,1993,3,4,ENVIRONMENTAL IMPACTS OF ELECTRICITY-GENERATION - SOME PUBLIC-POLICY DIMENSIONS,Given the increased political salience of environmental constraints on the energy sector at large| and on power generation in particular| some of the principal policy issues which impinge upon the electricity supply industry (ESI) are examined. Particular emphasis is placed on the two most prominent issues: acid rain and global warming. More emphasis is given to supply-side issues rather than demand-side responses (such as least cost planning). The paper then examines the major characteristics of the UK's stock of generating plant and some of the means available for the ESI to adjust this stock in the light of both specific environmental and wider political pressures. 4084,1993,3,2,ENVIRONMENTAL IMPACTS OF NUCLEAR-POWER - PAST EXPERIENCE AND FUTURE-PROSPECTS,The environmental impacts of nuclear power generation are considered for the whole fuel cycle| from the mining of uranium to provide fuel for nuclear reactors right through to the disposal of radioactive wastes and the decommissioning of power stations. This is done for existing reactor types and possible future developments. The radiological impact of routine low level discharges of activity into the environment is small compared with that from natural background radioactivity| while risks to operators arising from exposure to ionising radiation are comparable with those experienced in other safe industries. The quantities of waste produced by the nuclear industry are modest compared with many other industries| and the disposal of most of it is a routine operation; the decommissioning of nuclear power stations at the end of their useful lives can be seen as a large waste management exercise. The potential for an accident in the UK| on the scale of the Chernobyl incident| is remote. Overall| nuclear power is well controlled and can be seen to have environmental benefits compared with other forms of power generation. Its many advantages include the reduction in greenhouse gases which contribute to global warming and other atmospheric pollutants which contribute to acid rain. Nuclear power adds desirable diversity to electricity supply| increasing the reliability of meeting energy needs. 4087,1993,3,3,ENVIRONMENTAL-IMPACT OF EUROPEAN PAPERMAKING - A COMPARISON OF PRIMARY AND RECYCLED FIBER SCENARIOS,A long-term scenario analysis of the environmental effects of different fibre raw materials has been carried out for European papermaking. The expected environmental impacts have been obtained through mathematical simulations. The results indicate that| in Europe| the use of large amounts of primary fibre| i.e. fibre derived from well-managed forests| is environmentally advantageous-assuming that excess waste paper is collected and used as biofuel-in comparison with a situation in which increasing amounts of collected waste paper form the main raw material for papermaking. It is believed that primary fibre will be preferred as efforts are increased to combat global warming. 2659,1993,2,3,ESTIMATION OF LOCAL PRECIPITATION STATISTICS REFLECTING CLIMATE-CHANGE,A stochastic approach is developed to estimate the probability of wet days| and the mean and standard deviation of local daily nonzero precipitation reflecting global climate change scenarios. The approach is based on the analysis of daily atmospheric circulation patterns (CPs) and the linkage between types of CPs and daily precipitation. Three CP data sets are used for the 500-hPa pressure field: 40-year historical| 10-year 1 X CO2| and 10-year 2 X CO2 scenarios obtained from the atmospheric general circulation model of the Canadian Climate Centre. CP types obtained by clustering techniques and their frequency distribution are similar for the three data sets. The linkage between CP types and precipitation considers an additional variable| the spatial average pressure height within each CP type. The difference in pressure heights among the three CP data sets makes it possible to estimate the effect of global change on local precipitation statistics. Under the dry continental climate of eastern Nebraska the effect of 2 X CO2 scenario on local precipitation regime is spatially variable and significant: the number of wet days slightly decreases but both the mean and variance of daily precipitation increase resulting in a more variable precipitation regime.
3992,1993,2,3,ESTIMATIONS OF A GLOBAL SEA-LEVEL TREND - LIMITATIONS FROM THE STRUCTURE OF THE PSMSL GLOBAL SEA-LEVEL DATA SET,Among the possible impacts on environmental conditions of a global warming expected as a consequence of the increasing release of CO2 and various other greenhouse gases into the atmosphere| a predicted rise in global sea level is considered to be of high importance. Thus| quite a number of recent studies have focused on detecting the ''global sea level rise'' or even an acceleration of this trend. A brief review of these studies is presented| showing| however| that the results are not conclusive| though most of the studies have been based on a single global data set of coastal tide gauge data provided by the Permanent Service for Mean Sea Level (PSMSL). A detailed discussion of a thoroughly revised subset reveals that the PSMSL data set suffers from three severe limitations: (1) the geographical distribution of reliable tide gauge stations is rather uneven with pronounced concentrations in some areas of the northern hemisphere (Europe| North America| Japan)| and much fewer stations on the southern hemisphere where particularly few stations are located in Africa and in Antarctica; (2) the number of stations recording simultaneously at any time is far less than the total number of stations with the maximum within the interval between 1958 and 1988; (3) the number of long records is extremely small and almost all of them originate from a few regions of the northern hemisphere. The sensitivity of the median of the local trends to these temporal and spatial limitations is discussed by restricting the data set in both the spatial and temporal distribution. It is shown that the data base is insufficient for determining an integral value of the global rise in relative sea level. The effect of polar motion on sea level is modelled and it turns out to be locally of the order of 0.5 mm/yr| affecting regional trends to an order of 0.1 mm/yr. Thus| this effect can be neglected on time scale of decades to a hundred years. Though the data set is insufficient for determining an integral sea level rise| the data| nevertheless| are providing information concerning regional trends in sea level and even temporal variations in these regional patterns. Thus| the most comprehensive subset of the data reveals the existence of a significant interdecadal east-west fluctuation of the oceans possibly indicating some kind of teleconnection. Besides the limitations of the data set| the physical nature of the long term changes in relative sea level| which by no means are globally uniform| might render any globally averaged value of relative sea level rise useless for detecting climatic impacts or validating climate models. 3981,1993,3,3,EVALUATIONS OF FERTILIZATION OF THE OCEANS AS A COUNTERMEASURE OF CO2 PROBLEM,Fertilization technique is one of the countermeasures using the ocean| that can be used against the global warming. Fertilazation of the oceans with nutrients| such as nitrogen and phosphate| can promote the propagation of plant biota| leading to a decrease in the surface-ocean partial pressure of CO2| drawing down CO2 from the atmosphere. 3958,1993,4,7,EVIDENCE ON THE CLIMATE IMPACT OF SOLAR VARIATIONS,Friis-Christensen and Lassen report a close correspondence in the last 100 years between average Northern Hemisphere temperatures and changes in the length of the solar magnetic cycle. Observations of the sun and a number of solar-type stars suggest the explanation for this correlation. They reveal that (a) changes in the length of the magnetic activity cycle are correlated with changes in the amplitude of surface magnetic activity; (b) the amplitude changes in turn are positively correlated with changes in the sun's brightness. These relationships connect changes in the length of the solar cycle with solar irradiance changes. They supply a physical mechanism for the connection between terrestrial temperatures and the length of the solar cycle reported by Friis-Christensen and Lassen. Application of the same results to the history of solar surface magnetic activity since the Maunder Minimum yields the result that the change in solar irradiance from 1700 to the present could have been as small as 0.1% or as large as 0.7%. The mid-point of that range| a change in solar irradiance of 0.4%| is sufficient to explain all or most of the recovery from the Little Ice Age of the 17th Century and most of the half-degree global warming observed during the last 100 years. Satellite observations of solar irradiance over the 1978-1989 period have revealed a climatically insignificant brightness change of 0.1% over that period. Other stars similar to the sun display climatically significant changes of up to 0.6%| suggesting that at other times or over longer periods of time the sun may also change by larger amounts than were observed from 1978-1989.
4055,1993,2,4,EVOLUTION OF DARWIN FINCHES CAUSED BY A RARE CLIMATIC EVENT,Populations of animals and plants often undergo conspicuous ecological changes when subjected to climatic extremes. Evolutionary changes may accompany them but are less easily detected. We show that Darwin's finches on a Galapagos island underwent two evolutionary changes after a severe El Nino event caused changes in their food supply. Small beak sizes were selectively favoured in one granivorous species when large seeds became scarce. The effects of selection were transmitted to the next generation as a result of high trait heritabilities. Hybridization between this species and two others resulted in gene exchange| but only after the El Nino when hybrid fitness was much enhanced under the altered feeding conditions. These observations imply that if global warming increases the frequency or severity of El Nino events on the Galapagos| microevolutionary changes in animal and plant populations are to be anticipated. 4044,1993,3,4,EXPLORING THE GAP - TOP-DOWN VERSUS BOTTOM-UP ANALYSES OF THE COST OF MITIGATING GLOBAL WARMING,Top-down and bottom-up modelling techniques have been used to answer the question of how much would it cost to reduce greenhouse gas emissions. These two types of models| however| were conceived and designed through different disciplines| for different purposes and lead to very different conclusions. Recent attempts to compare the two modelling approaches illustrate the difficulty in reconciling their results. In this paper| both modelling techniques are described and discussed| and the gap between their results is explored. 2681,1993,2,4,FACILITY FOR STUDYING THE EFFECTS OF ELEVATED CARBON-DIOXIDE CONCENTRATION AND INCREASED TEMPERATURE ON CROPS,The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature| and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia)| which ran from December 1990 through to August 1991| the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m-3 for targets of 350 and 700 cm3 m-3 respectively. Temperatures were set to follow outside ambient or outside ambient +4-degrees-C| and hourly means were within 0.5-degrees-C of the target for 92% of the time for target temperatures greater than 6-degrees-C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifical light with natural photoperiod) was 2% greater than the total measured outside over the same period.
3996,1993,4,4,FOREST WILDFIRES AS A RECENT SOURCE OF CO2 AT NORTHERN LATITUDES,Since 1977| the extent of forest wildfires in the boreal and western regions of North America increased 6- to 9-fold over long-term trends| and an estimated 132 x 10(6) ha of temperate and boreal forest burned across the northern hemisphere. Emissions during and after burning may have been a significant feedback to global warming. Simulated carbon budgets indicated a hemispheric release of 1.4 Pg C during burning and 4.1 Pg C gross from CO2 fluxes postfire. The total release (5.5 Pg C) was 43% of the biospheric CO2 release to the atmosphere| 1977-1990. Over the next century (1991-2090)| continuing emissions from wood and soil decomposition will release an additional 6.9 Pg C gross. A large CO2 release was contrary to assumptions of little net carbon flux in the temperate and boreal forests. The pattern of attenuated CO2 release in northern forests also contrasted with sharp emission peaks in tropical deforestation. A simulation experiment indicated that the CO2 pulse from direct emissions per unit area was 10-fold larger in tropical deforestation than in northern forest wildfires on average; postfire release in the northern systems| however| was about 10 times longer in duration and only slightly less overall than in tropical deforestation fires. 2685,1993,2,3,FOREST-FIRES IN RUSSIA - CARBON-DIOXIDE EMISSIONS TO THE ATMOSPHERE,Boreal forests of Russia play a prominent role in the global carbon cycle and the flux of greenhouse gases to the atmosphere. Large areas of Russian forest burn annually| and contributions to the net flux of carbon to the atmosphere may be significant. Forest fire emissions were calculated for the years 1971-1991 using fire frequency and distribution data and fuel and carbon density for different forest ecoregions of Russia. Both direct carbon release and indirect post-fire biogenic carbon flux were estimated. From 1971 to 1991 the annual total forest area burned by wildfire ranged from 1.41 X 10(6) to 10.0 X 10(6) ha. Approximately 15 000 - 25 000 forest fires occurred annually during this period. Mean annual direct CO2-C emissions from wildfire was approximately 0.05 Pg over this 21 -year period. Total post-fire biogenic CO2-C emissions for 1971-1991 ranged from 2.5 to 5.9 Pg (0.12-0.28 Pg annually). Forest fires and other disturbances are expected to be a primary mechanism driving vegetation change associated with projected global climate change. Future forest fire scenarios in Russia based on general circulation model projections suggest that up to 30-50% of the land surface area| or 334 x 10(6) to 631 x 10(6) ha of forest| will be affected. An additional 6.7 x 10(6) to 12.6 x 10(6) ha of Russian boreal forest are projected to burn annually if general circulation model based vegetation-change scenarios are achieved within the next 50 years. The direct flux Of CO2-C from future forest fires is estimated to total 6.1-10.7 Pg over a 50-year period. Indirect post-fire biogenic release of greenhouse gases in the future is expected to be two to six times greater than direct emissions. Forest management and fire-control activities may help reduce wildfire severity and mitigate the associated pulse of greenhouse gases into the atmosphere.
4066,1993,3,2,GAS EMISSIONS FROM LANDFILLS AND THEIR CONTRIBUTIONS TO GLOBAL WARMING,The contribution of methane from UK landfills is described in relation to total gas emissions to the atmosphere and how these have been shown to contribute to global warming. The known effects that methane has on the atmosphere are reviewed and the relationship to those effects caused by other greenhouse gases is described. A methodology utilized in assessing the quantity of landfill gas emitted from landfill sites is described| as are the main principles used in a gas generation model Results of a survey| field trials and categorisation of the many types of site condition and waste mixtures are explained| including the techniques incorporated into the model to allow a potential gas yield to be predicted. The factors that limit this potential yield of methane such as the oxidizing capacity of soil are identified and assessed The potential effect of landfill-gas utilisation on the total emission and the economic viability of such schemes is reviewed in relation to reduced carbon dioxide and methane emissions. Combustion of landfill gas is shown to make a small net contribution to the potential equivalent CO2 reductions. The economics of energy recovery from landfill gas associated with CO2 reductions are shown lo be significantly better than other alternative energy forms. 3979,1993,3,3,GENERATION OF GREENHOUSE-EFFECT GASES FROM DIFFERENT LANDFILL TYPES,Recently much attention is focussed on the problems of global warming due to greenhouse effect gases| notably carbon dioxide and methane. Because these gases cause important problems to the global environment| their generation from landfill sites containing solid wastes has drawn attention and their environmental impact is causing concern. Generally| the gases associated with a greenhouse effect include carbon dioxide| methane and nitrous oxide. However| there are no general basic data available concerning gases generated from biodegradation of solid wastes in landfill sites. Specifically| no assessment has been made concerning greenhouse effect gases from different landfill types. This paper proposes a quantitative model for estimating the gasification rate by different landfill types. The model is based on measurement data for a long-term material balance for an aerobic landfill and an anaerobic landfill| obtained with two types of large-scale lysimeters. This paper will also give an estimate for the amount of greenhouse effect gases by for different types of landfill and propose countermeasures for their reduction. 2658,1993,2,4,GLOBAL CLIMATE-CHANGE AND AGRICULTURAL PRODUCTIVITY IN SOUTHERN AFRICA,An analysis tool was developed to simulate primary productivity and crop yields for both present and possible future climate conditions. Southern Africa was delineated into 712 relatively homogeneous climate zones| each with specific climate| soil and vegetation response information. The primary productivity and crop yield models were linked with the climate zones via a cell-based agrohydrological model| with the final output coordinated using a Geographic information System. The results of this preliminary study show a large dependence of production and crop yield on the intra-seasonal and inter-annual variation of rainfall. The most important conclusion from the study is the readiness of the developed tool and associated infrastructure for future analysis into social| technological and political responses to food security in southern Africa.
2682,1993,2,4,GLOBAL CLIMATE-CHANGE AND TERRESTRIAL NET PRIMARY PRODUCTION,A process-based model was used to estimate global patterns of net primary production and soil nitrogen cycling for contemporary climate conditions and current atmospheric CO2 concentration. Over half of the global annual net primary production was estimated to occur in the tropics| with most of the production attributable to tropical evergreen forest. The effects of CO2 doubling and associated climate changes were also explored. The responses in tropical and dry temperate ecosystems were dominated by CO2| but those in northern and moist temperate ecosystems reflected the effects of temperature on nitrogen availability.
2683,1993,3,3,GLOBAL CLIMATE-CHANGE| UNITED-STATES AGRICULTURE| AND CARBON-DIOXIDE,What should U.S. agriculture do to adapt for possible climate change and what can it do to reduce greenhouse gas emissions? An evaluation indicates that| unless there is a decline of about one-fourth in total crop yields| the U.S. land resource base will be adequate and food security can be met. The impacts of climate change on individual crop production regions are hard to predict| however| and may be either negative or positive. The assumption must be made that agriculture faces an uncertain future and| therefore| must rely upon experience| adoption of proven technologies| development of new technologies| and improved husbandry of land| water| and energy resources. Carbon dioxide| one of the greenhouse gases| can be emitted| as well as sequestered| in large amounts by agriculture. Agriculture has a great opportunity to help mitigate climate change by stashing CO2 as C in soil and vegetation and by displacing fossil fuels. Practices requiring good agricultural husbandry| which should be implemented anyway| can be quite effective for sequestering C. For cropland| these practices include building soil organic matter levels| improving soil fertility| and growing more food on less land. Carbon pools are maintained| restored| and enlarged on croplands by increased use of conservation tillage| improved use of animal and other wastes| minimized dryland fallowing| and preservation of marginal lands. On forestlands| reforestation| forestation (including tree planting on conservation reserve program land)| and improved forest harvesting practices maintain and enlarge C-pools. Preservation of wetlands does much to maintain C-pools. Collectively| these practices can potentially offset not only the CO2 emissions from U.S. agriculture| but also part of that from U.S. sources outside of agriculture.
4091,1993,4,4,GLOBAL TEMPERATURE MONITORING FROM SPACE,Global and regional temperature variations in the lower troposphere and lower stratosphere are examined for the period 1979-92 from Microwave Sounder Unit (MSU) data obtained by the TIROS-N series of NOAA operational satellites. In the lower troposphere| globally-averaged temperature variations appear to be dominated by tropical El Nino (warm) and La Nina (cool) events and volcanic eruptions. The Pinatubo volcanic eruption in June 1991 appears to have initiated a cooling trend which persisted through the most recent data analyzed (July| 1992)| and largely overwhelmed the warming from the 1991-92 El Nino. The cooling has been stronger in the Northern Hemisphere than in the Southern Hemisphere. The temperature trend over the 13.5 year satellite record is small (+0.03 degrees C) compared to the year-to-year variability (0.2 degrees-0.4 degrees C)| making detection of any global warming signal fruitless to date. However| the future global warming trend| currently predicted to be around 0.3 degrees C/decade| will be much easier to discern should it develop. The lower stratospheric temperature record is dominated by warm episodes from the Pinatubo eruption and the March 1982 eruption of El Chichon volcano. 3980,1993,2,2,GLOBAL VEGETATION CHANGE PREDICTED BY THE MODIFIED BUDYKO MODEL,A modified Budyko global vegetation model is used to predict changes in global vegetation patterns resulting from climate change (CO2 doubling). Vegetation patterns are predicted using a model based on a dryness index and potential evaporation determined by solving radiation balance equations. Climate change scenarios are derived from predictions from four General Circulation Models (GCM's) of the atmosphere (GFDL| GISS| OSU| and UKMO). Global vegetation maps after climate change are compared to the current climate vegetation map using the kappa statistic for judging agreement| as well as by calculating area statistics. All four GCM scenarios show similar trends in vegetation shifts and in areas that remain stable| although the UKMO scenario predicts greater warming than the others. Climate change maps produced by all four GCM scenarios show good agreement with the current climate vegetation map for the globe as a whole| although over half of the vegetation classes show only poor to fair agreement. The most stable areas are Desert and Ice/Polar Desert. Because most of the predicted warming is concentrated in the Boreal and Temperate zones| vegetation there is predicted to undergo the greatest change. Specifically| all Boreal vegetation classes are predicted to shrink. The interrelated classes of Tundra| Taiga| and Temperate Forest are predicted to replace much of their poleward mostly northern) neighbors. Most vegetation classes in the Subtropics and Tropics are predicted to expand. Any shift in the Tropics favoring either Forest over Savanna| or vice versa| will be determined by the magnitude of the increased precipitation accompanying global warming. Although the model predicts equilibrium conditions to which many plant species cannot adjust (through migration or microevolution) in the 50-100 y needed for CO2 doubling| it is nevertheless not clear if projected global warming will result in drastic or benign vegetation change. 4086,1993,3,3,GLOBAL WARMING - TRENDS AND EFFECTS,As animals we have been a remarkably successful species; but also as animals we are vulnerable to environmental| in particular climate change. Such change is accelerating as a result of human activity| and global warming may already be taking place. Although we can foresee the trends| we cannot yet be specific about the results. Change usually proceeds by steps rather than gradients. But warming would probably include new risks to human health and contribute to an increase in human displacement. Of course climate change is only one among other complex problems facing human society| but it is closely related to them all| including population increase| environmental degradation and loss of biodiversity. We cannot prevent global warming but we can anticipate and mitigate some of its worst effects. Peoples and governments still need persuading of the need for action and of the magnitude of the issue at stake. 4011,1993,2,4,GLOBAL WARMING AND FOREST-FIRES IN CANADA,The looming possibility of global warming raises legitimate concerns for the future of the forest resource in Canada. While evidence of a global warming trend is not conclusive at this time| governments would be wise to anticipate| and begin planning for| such an eventuality. The forest fire business is likely to be affected both early and dramatically by any trend toward warmer and drier conditions in Canada| and fire managers should be aware that the future will likely require new and innovative thinking in forest fire management. This paper summarizes research activities currently underway to assess the impact of global warming on forest fires. and speculates on future fire management problems and strategies. 4017,1993,2,4,GLOBAL WARMING AND THE INSURANCE INDUSTRY,In the last few decades| the international insurance industry has been confronted with a drastic increase in the scope and frequency of great natural disasters. The trend is primarily attributable to the continuing steady growth of the world population and the increasing concentration of people and economic values in urban areas. An additional factor is the global migration of populations and industries into areas such as coastal regions| which are particularly exposed to natural hazards. The natural hazards themselves| on the other hand| have not yet shown any significant increase. In addition to the problems the insurance industry has with regard to pricing| capacity and loss reserves| the assessment of insured liabilities| preventive planning and the proper adjustment of catastrophe losses are gaining importance. The present problems will be dramatically aggravated if the greenhouse predictions come true. The increased intensity of all convective processes in the atmosphere will force up the frequency and severity of tropical cyclones| tornados| hailstorms| floods and storm surges in many parts of the world with serious consequences for all types of property insurance. Rates will have to be raised and in certain coastal areas insurance cover will only be available after considerable restrictions have been imposed| as for example significant deductibles and low liability or loss limits. In areas of high insurance density the loss potential of individual catastrophes can reach a level at which the national and international insurance industries will run into serious capacity problems. Recent disasters showed the disproportionately high participation of reinsurers in extreme disaster losses and the need for more risk transparency if the insurance industry is to fulfil its obligations in an increasingly hostile environment. 3989,1993,3,4,GLOBAL WARMING AND THE INTERNAL ENERGY MARKET - POLICY INTEGRATION OR POLARIZATION,This paper examines to what extent the European Community is progressing towards realizing its objective of integrating energy and environment policies by looking at two current policy developments; the CO2 reduction strategy and the internal energy market (IEM) initiative. It argues that to date adjustments to energy policy have been made essentially at the margin| resulting in a number of policy tensions. The IEM proposals are based on a very narrow definition of efficiency and fail to address crucial areas like the promotion of renewable energy sources or end-use efficiency. Not all the implications are negative but incidental benefits hardly point to better integration. 4022,1993,4,4,GLOBAL WARMING AND THE PROBLEM OF TESTING FOR TREND IN TIME-SERIES DATA,In recent years a number of statistical tests have been proposed for testing the hypothesis that global warming is occurring. The standard approach is to examine one or two of the more prominent global temperature datasets by letting Y(t) = a + bt + E(t) where Y(t) represents the temperature at time t| and E(t) represents error from the trend line| and to test the hypothesis that b = 0. Several authors have applied these tests for trend to determine whether or not a significant long-term or deterministic trend exists| and have generally concluded that there is a significant deterministic trend in the data. However| we show that certain autoregressive-moving average (ARMA) models may also be very reasonable models for these data due to the random trends present in their realizations. In this paper| we provide simulation evidence to show that the tests for trend detect a deterministic trend in a relatively high percentage of realizations from a wide range of ARMA models| including those obtained for the temperature series| for which it is improper to forecast a trend to continue over more than a very short time period. Thus| we demonstrate that trend tests based on models such as Y(t) = a + bt + E(t) for the purpose of prediction or inference concerning future behavior should be used with caution. Of course| the projections that the warming trend will extend into the future are largely based on such factors as the buildup of atmospheric greenhouse gases. We have shown here| however| that based solely on the available temperature anomaly series| it is difficult to conclude that the trend will continue over any extended length of time. 4051,1993,2,3,GLOBAL WARMING FROM CHLOROFLUOROCARBONS AND THEIR ALTERNATIVES - TIME SCALES OF CHEMISTRY AND CLIMATE,The halocarbons (chlorofluorocarbons| CFCs| and their replacement chemicals: the hydrochlorofluorocarbons| HCFCs| and the hydrofluorocarbons| HFCs) are greenhouse gases. The atmospheric accumulation of these gases is expected to add to the global warming predicted for expected increases of CO2| CH4| N2O| tropospheric ozone and H2O. Over the next decades| production of CFCs is scheduled to be phased out| while emissions of their alternatives are expected to increase. A simple model is used to illustrate the methodology for determining the time variations of the radiative forcing and temperature changes attributable to the direct greenhouse effect from potential emissions of the halocarbons. Although there are uncertainties associated with the lifetimes of the greenhouse gases| CFCs and their substitutes| the future growth rates of these gases| and the parameters used to simulate the response of the Earth-climate system| the method serves to illustrate an important aspect of the greenhouse warming issue beyond what is provided by the various greenhouse warming indices. Our results show that for likely substitution scenarios| the warming due to halocarbons will correspond to 4-10% of the total expected greenhouse warming at the year 2100. However| uncontrolled growth of the substitutes could result in an eight-fold increase in halocarbon production and a doubling of the halocarbon contribution by 2100. 4007,1993,2,2,GLOBAL WARMING IMPACTS OF TRANSPORT,Global warming is expected to occur due to carbon dioxide and other gases emitted in the course of human activities. Due to uncertainties about atmospheric chemistry| few attempts have been made to quantify the impact of emissions of NO(x)| non-methane hydrocarbons and carbon monoxide. Atmospheric chemistry modelling at Harwell Laboratory has resulted in preliminary estimates of the impact of trace gases including NO(x)| many hydrocarbon species| carbon monoxide and water vapour on global warming. These estimates have been applied to emissions from transport| with particular attention to cars. It is found that the use of three-way catalysts on cars could reduce their global warming impact. IDI diesel engines have still less global warming impact. High NO(x)| CO and hydrocarbon emissions from DI diesels could result in a higher impact from these engines than from IDI diesels. Emissions from air-craft are injected into the troposphere at the height where they have a maximal effect on global warming. Although modelling of aircraft impact is at a very early stage| the first results indicate that air travel could become an important cause of global warming. 2666,1993,2,4,GREAT-LAKES TOXIC SEDIMENTS AND CLIMATE-CHANGE - IMPLICATIONS FOR ENVIRONMENTAL REMEDIATION,Toxic sediments remediation represents a potentially long-term environmental programme in the Great Lakes Basin. The prospect of declining lake levels due to global climate change in coming decades presents challenges to environmental policy makers concerned with choosing appropriate toxics clean-up methods and timing. It is important to integrate the possibility of declining lake levels into Great Lakes toxic sediments remediation in order to ensure that long-term environmental policy is not in conflict with the potential regional hydrological impacts of climate change.
4088,1993,3,4,GREENHOUSE GAS EMISSIONS| ABATEMENT AND CONTROL - THE ROLE OF COAL,The basis for quantifying the relative effect of greenhouse gas emissions from coal utilisation is discussed. Emission factors (g of C/MJ) need to include greenhouse gas emissions and energy losses throughout the fuel cycle in order to compare the fuels. Nevertheless| CO2 is the most important greenhouse gas from coal. Emission factors have decreased due to improved efficiency of coal use. The scope for further improvements in efficiency of conventional and advanced power generation is assessed. Control of CO2 emissions is viewed as a less promising option owing to the high cost and energy penalty of most methods. It is concluded that there is no firm basis for evaluating the effect of reducing emissions on their global warming potential. However| it is desirable that available technologies be implemented to reduce emissions by improved efficiency. 4071,1993,3,3,GREENHOUSE GASES FROM BIOMASS AND FOSSIL-FUEL STOVES IN DEVELOPING-COUNTRIES - A MANILA PILOT-STUDY,Samples were taken of the combustion gases released by household cookstoves in Manila| Philippines. In a total of 24 samples| 14 cookstoves were tested. These were fueled by liquefied petroleum gas (LPG)| kerosene (three kinds of stoves)| charcoal| and wood. Ambient samples were also taken. All samples were analyzed for CO2| CO| CH4| N2O| and total non-methane organic compounds (TNMOC). Results generally confirm increasing emissions for most products of incomplete combustion moving down the ''energy ladder'' from gaseous to liquid to processed solid to unprocessed solid fuels. Although the sample size and number of background samples were too small to give great confidence in the results| extrapolation of the emission ratios (each gas relative to CO2) to global estimates indicates that published global inventories of several gases important in atmospheric chemistry may be somewhat too small for the fuelwood combustion category. When weighted by global warming potentials| the greenhouse impact of the emissions of non-CO2 greenhouse gases from wood combustion may rival or exceed those from CO2 alone. If verified| this could have substantial implications for energy and environmental policies in developing countries. These tentative findings indicate that more measurements of this type in developing countries would be justified. 4048,1993,3,3,GREENHOUSE POLICY,How quickly we must respond| and by how much| to the threat of global warming depends on how much increasing greenhouse-gas concentrations will change climate| and what the consequences of such a climate change will be. Yet our knowledge of these climatic changes is uncertain. I provide a basis for understanding why this is so with information about the greenhouse effect| climate modeling and simulation| and economic and policy analysis. I examine a sequential-decision strategy for abating climate change wherein either moderate emissions reduction-energy conservation alone-or aggressive emissions reduction-energy conservation plus switching to non-fossil fuels-is begun in the near-term (1992 to 2002). Results show that the difference in emission rates and costs between the moderate and aggressive near-term policies is much smaller than the difference in emission rates and costs between the different climate targets. Thus| if future research shows that the damage cost of climate change is high| the optimum climate target will be low and the global consumption of fossil fuels must be sharply reduced much earlier than if the damage cost of climate change is low| regardless of which near-term policy is chosen. 4025,1993,3,3,GREENHOUSE-GAS EMISSIONS FROM THE USE OF NEW FUELS FOR TRANSPORTATION AND ELECTRICITY,Concern about global warming| poor urban air quality and dependence on insecure sources of oil are leading many nations to examine alternative energy sources and technologies for transportation and electricity generation. This analysis shows that most of the near-term fossil fuel-based alternatives would not dramatically reduce emissions of greenhouse gases. However| in the long run| several ultra-low-emission fuels and technologies are available. The major uncertainties in the analysis are the efficiency of energy use| the warming potential of greenhouse gases other than CO2 and the economic and political context in which energy is used. 4054,1993,5,4,GREENLAND - A TEMPTATION AND A CHALLENGE,Research into the causes of global warming resulting from anthropogenic factors has shown that the causes of climatic change are far more complex than has been supposed. In particular| it has directed attention to enormous climatic fluctuations that occurred in the very distant past| long before mankind appeared. The recent completion of the drilling phase of the Greenland Ice-core Project (GRIP) has already thrown much light on longterm changes in the Northern Hemisphere. It is clear-that there were many substantial changes in mean temperature and in the course of the Gulf Stream during the last glaciation. 4035,1993,2,3,GROUNDWATER FLUXES IN THE GLOBAL HYDROLOGIC-CYCLE - PAST| PRESENT AND FUTURE,A quantification of groundwater fluxes in the hydrologic cycle for large river basins and on a global scale is reported in this paper. Groundwater contributions to river runoff (i.e. baseflow)| direct submarine groundwater discharge to the ocean floor| and salt throughput to oceans and seas are analyzed. The baseflow/precipitation and baseflow/river runoff ratios are found to be approximately 10% and 30% on a world-wide basis| showing great geographical variability across the major continents of the Earth. Direct groundwater discharge to the ocean floor is only 6% of the total water influx to oceans and seas| yet| it contributes a salt load to oceans and seas that is approximately 50% of the salt loading by rivers. Factors and uncertainties germane to global groundwater balancing| recent anthropogenic modifications of groundwater contributions to runoff| and the likely role of potential global warming in groundwater circulation are discussed. Over the last 300 years baseflow contribution to river runoff has slightly increased| whereas the river runoff has declined as a result of anthropogenic modifications to the natural environment. Assuming a 10% increase in global annual precipitation from potential greenhouse warming| the associated increases in baseflow contribution to river runoff and direct groundwater discharge to oceans would amount to 1200 km3 year-1 and 260 km3 year-1| respectively. The additional salt load to oceans and seas by direct groundwater flow is estimated at 140 000 000 t year-1. Salinity of oceans and seas could rise if their water volumes do not increase enough to offset the larger salt load. 2687,1993,4,4,HIGH-LATITUDE OCEANIC VARIABILITY ASSOCIATED WITH THE 18.6-YEAR NODAL TIDE,Ocean temperatures in the upper 250 m in the northern North Pacific (60-degrees-N| 149-degrees-W) increased bt more than 1-degrees-C from 1972 to 1098 but are now decreasing. Subsurface temperature anomalies are well correlated (approximately 0.58) with the air temperature anomalies at Sitka| Alaska; hence the coastal air temperatures can be used as a proxy data set to extend the ocean temperature time series back to 1828. Up to 30% of the low-frequency variance can be accounted for with the 18.6-year nodal signal. Additionally. spectral analysis of these air temperature variations indicates a significant low-frequency peak in the range of the 18.6-year signal. Similar low-frequency signals have been reported for Hudson Bay air temperatures since 1700| for sea surface temperatures in the North Atlantic from 1876 to 1939| and for sea level in the high-latitude southern hemisphere. The water column temperature variations presented here are the first evidence that the upper ocean is responding to this very long period tidal forcing. An enhanced high-latitude response to the 18.6-year forcing is predicted by equilibrium tide theory| and it should be most evident at latitudes poleward of about 50-degrees. These low-frequency ocean-atmosphere variations must - be considered in high-latitude assessments of global climate change| since they are of the same magnitude as many of the predicted global changes.
4038,1993,4,1,HOW SENSITIVE IS THE WORLDS CLIMATE,We estimate climate sensitivity from observed climate change on time scales ranging from the 100 000-year periods of major ice ages to brief periods of cooling after major volcanic eruptions. The real-world data indicate that climate is very sensitive| equivalent to a warming of 3 +/- 1-degrees-C for doubled atmospheric CO2. Observed global warming of approximately 0.5-degrees-C in the past 140 years is consistent with anthropogenic greenhouse gases being the dominant climate-forcing in that period. But interpretation of current climate change is extraordinarily complex| because of lack of observations of several climate forcings as well as an unpredictable chaotic aspect of climate change. Climate change during the next decade may help confirm knowledge of climate sensitivity| if global climate forcings are accurately observed. 3999,1993,2,4,HUMAN INFLUENCE IN GEOMORPHOLOGY,The human influence in geomorphology has a long history| and major contributions have| for example| been made by Shaler| McGee| Gilbert and Marsh. However| in the last two decades concern with global environmental change has brought the role of anthropogeomorphology into sharper focus. Global warming| if it occurs| will have important implications for many geomorphological processes and phenomena as a result of the direct effects of warming| as a consequence of other related climatic changes (e.g. precipitation change) and as a result of climatically moderated changes in major geomorphologically significant variables (e.g. vegetation cover). Large uncertainties exist with respect to such matters as hydrological response| the frequency of tropical cyclones| the speed and degree of permafrost degradation| the response of glaciers and ice caps| the extent of sea level rise| the reaction of beaches to rising sea levels| and the state of wetlands| deltas and coral reefs. Other human activities may serve to compound the effects of global warming on geomorphological processes. Given the uncertainties of so many of the environmental changes| there is a great need to obtain a greater understanding of the rates and mechanisms of landform response. Geomorphologists need| inter alia| to establish long-term study sites that will generate base-line data| to monitor the location and rate of change using sequential cartographic and remote sensing materials| to determine information on natural background levels and long-term trends by means of data gained from cores| to gain a more profound understanding of the operation of geomorphological systems particularly with regard to sensitivities and thresholds| and to appreciate the consequences of deliberate manipulation of environmental systems by humans. 4043,1993,3,4,IMPLEMENTATION OF GREENHOUSE-GAS REDUCTIONS IN THE EUROPEAN-COMMUNITY - INSTITUTIONAL AND CULTURAL-FACTORS,The European Community is the only supranational entity with legally constituted policy sovereignty over its member countries. However| attempts to establish EC policy on global warming have coincided with intensifying conflict over moves to greater monetary and political union. The roles of The Netherlands| Germany| and the UK are contrasted in some detail| especially in relation to degrees of interventionism. The study concludes that a proposed carbon tax is likely to be favoured as leaving the least footprint of central political authority. However| the Community has also developed considerable informal sophistication to compensate for the formal limitations of its authority over member states. This is influenced by a network of NGOs able to pursue policy aims at the local level. 2689,1993,4,4,INDONESIA AND GLOBAL CLIMATE-CHANGE NEGOTIATIONS - POTENTIAL OPPORTUNITIES AND CONSTRAINTS FOR PARTICIPATION| LEADERSHIP| AND COMMITMENT,The author discusses factors likely to affect Indonesia's participation in global climate change mitigation negotiations. These include Indonesia's performance to date in the international arena and its track record for compliance with agreements; domestic challenges such as demographic pressures| economic growth| deforestation| and energy consumption; the institutional culture of the government; and the activities and limitations of the legal system| non-governmental organizations| and business. The author concludes that| while the Indonesian government may be a vocal advocate for 'sustainable development'| it has little ability to follow through on large-scale commitments to international efforts because of issues It faces at home.
4008,1993,4,4,INFRARED CROSS-SECTIONS AND GLOBAL WARMING POTENTIALS OF 10 ALTERNATIVE HYDROHALOCARBONS,Absorption cross sections have been obtained in the infrared atmospheric window| between 600 and 1500 cm-1| for 10 alternative hydrohalocarbons: HCFC22| HCFC123| HCFC124| HCFC141b| HCFC142b| HCFC225ca| HCFC225cb| HFC125| HFC134a and HFC152a. The measurements were made at three temperatures (287 K| 270 K and 253 K) with a Fourier transform spectrometer operating at 0.03 cm-1 apodized resolution. Integrated cross sections have been introduced into a two-dimensional radiative-chemical-dynamical model in order to calculate the global warming potential (GWP) of each gas. 3960,1993,4,3,INSENSITIVITY OF GLOBAL WARMING POTENTIALS TO CARBON-DIOXIDE EMISSION SCENARIOS,GLOBAL warming potentials for radiatively active trace gases (such as methane and chlorofluorocarbons) have generally been expressed1|2 relative to the time-integrated climate forcing per unit emission of carbon dioxide. Previous attempts to estimate the integrated climate forcing per unit CO2 emitted have focused on perturbations to steady-state conditions in carbon-cycle models. But for non-steady-state conditions| the integrated climate forcing from a CO2 perturbation depends both on the initial conditions and on future atmospheric CO2 concentrations. As atmospheric CO2 concentrations increase| the radiative forcing per unit CO2 emitted will become smaller because the strongest absorption bands will already be saturated. At the same time| higher concentrations of dissolved carbon in the surface ocean will reduce the ocean's ability to absorb excess CO2 from the atmosphere. Each of these effects taken alone would affect the climate forcing from a pulse of emitted CO2 by a factor of three or more; but here we show that| taken together| they compensate for each other. The net result is that the global warming potential of CO2 relative to other radiatively active trace gases is nearly independent of the CO2 emission scenario. Thus| the concept of the global warming potential remains useful| despite the nonlinearities in the climate system and uncertainties in future emissions. 4037,1993,2,4,LAKE LEVEL REGULATION AND SHORELINE EROSION ON FLATHEAD LAKE| MONTANA - A RESPONSE TO THE REDISTRIBUTION OF ANNUAL WAVE ENERGY,Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. Attention has focused on the absolute elevation of sea-level rise| whereas shoreline erosion may result more from the redistribution of wave energy over the duration of the sea-level rise. This study examines shoreline erosion in Flathead Lake| Montana| resulting from a redistribution of annual wave energy due to five decades of regulated lake levels by a dam at the lake's outlet. The annual rise in lake level is held for an extended duration at a regulated ''full pool'' level which is approximately 3 m above its natural base elevation. The total time for a complete cycle of lake level change also has been increased from 100 days to over 300 days. Alteration of the natural lake level fluctuation has resulted in a transfer of annual wave energy from base elevations corresponding to the pre-dam nearshore shelf| to elevations corresponding to the limnetic foreshore environment| thereby inducing lake-wide erosion. The most extensive erosion has occurred along the low-lying dissipative north shore of the lake. The redistribution of annual wave energy due to regulated lake level fluctuation is the main factor contributing to that erosion. The redistribution of annual incident wave energy is examined in terms of an increase in the duration of the complete natural lake-level cycle| a reduced range in lake level fluctuation| and an elevated full pool lake level. Both the duration of lake level cycle and range in water level fluctuation affect the distribution of incident wave energy and were found to be more important to shoreline erosion than an absolute elevated water level. An alternative regulation scheme incorporating concerns for both hydropower production and lake recreation is proposed and examined in terms of reducing erosion. Altering the regulated lake level fluctuation by changing the timing and increasing the rate of lake level drawdown| would result in a significant reduction in the amount of annual wave energy that reaches the eroding full pool shoreline| thereby reducing the potential for take-wide shoreline erosion. 4057,1993,2,4,LARGE INCREASES IN FLOOD MAGNITUDE IN RESPONSE TO MODEST CHANGES IN CLIMATE,RECENT examinations of the possible hydrological response to global warming have emphasized changes in average conditions| rather than individual flooding events1-5. Historical accounts suggest| however| that such events may have had a considerable regional impact6-9 even in the face of any relatively modest climate change8. Here I present a 7|000-year geological record of overbank floods for upper Mississippi river tributaries in mid-continent North America| which provides concrete evidence for a high sensitivity of flood occurrence to changing climate. During a warmer| drier period between about 3|300 and 5|000 years ago| the largest| extremely rare floods were relatively small-the size of floods that now occur about once every fifty years. After approximately 3|300 years ago| when the climate became cooler and wetter| an abrupt shift in flood behaviour occurred| with frequent floods of a size that now recurs only once every 500 years or more. Still larger floods occurred between about AD 1250 and 1450| during the transition from the medieval warm interval to the cooler Little ice Age. All of these changes were apparently associated with changes in mean annual temperature of only about 1-2-degrees-C and changes in mean annual precipitation of less-than-or-equal-to 10-20%. 4059,1993,2,4,LARGE-SCALE DYNAMICS AND GLOBAL WARMING,Predictions of future climate change raise a variety of issues in large-scale atmospheric and oceanic dynamics. Several of these are reviewed in this essay| including the sensitivity of the circulation of the Atlantic Ocean to increasing freshwater input at high latitudes; the possibility of greenhouse cooling in the southern oceans; the sensitivity of monsoonal circulations to differential warming of the two hemispheres; the response of midlatitude storms to changing temperature gradients and increasing water vapor in the atmosphere; and the possible importance of positive feedback between the mean winds and eddy-induced heating in the polar stratosphere. 3993,1993,5,4,LATEST PALEOCENE LITHOLOGIC AND BIOTIC EVENTS IN NERITIC DEPOSITS OF SOUTHWESTERN NEW-JERSEY,In the southwestern New Jersey Coastal Plain| four drill holes contain continuous neritic sedimentation across the Paleocene/Eocene boundary (calcareous nannofossil Zone NP 9/NP 10 boundary). Significant lithologic and biotic changes occur in these strata near the top of the Paleocene. Global warming| increased precipitation| and other oceanographic and climatic events that have been recognized in high-latitude| deep-oceanic deposits of the latest Paleocene also influenced mid-latitude| shallow-marine| and terrestrial environments of the western North Atlantic. The diverse| well-preserved calcareous nannofossil flora that is present throughout the entire New Jersey boundary section accurately places these events within the uppermost part of the upper Paleocene Zone NP 9. Several rapid but gradational changes occur within a 1.1-m interval near the top of Zone NP 9. The changes include (1) a change in lithology from glauconitic quartz sand to clay| (2) a change in clay mineral suites from illite/smectite-dominated to kaolinite-dominated| (3) a change in benthic foraminiferal assemblages to a lower diversity fauna suggestive of low-oxygen environments| (4) a significant increase in planktonic foraminiferal abundance| and (5) an increased species turnover rate in marine calcareous nannofossils. Pollen was sparse in the New Jersey drill holes| but terrestrial sporomorph species in Virginia exhibit increased turnover rates at a correlative level. Foraminiferal assemblages and lithology indicate that relative sea level rose in New Jersey at the same time as these late Paleocene events occurred in late Biochron NP 9. The higher sea levels influenced sediment type and absolute abundance of planktonic foraminifers in the deposits. Above the initial increase of kaolinite in the upper part of Zone NP 9| the kaolinite percentage continues to increase| and the maximum kaolinite value occurs in the uppermost part of Zone NP 9. There are few changes in either the sediments or the biota precisely at the Zone NP 9/NP 10 boundary in New Jersey. The clay-rich deposits with a high kaolinite clay mineral suite| the lowered diversity benthic foraminiferal assemblages| the abundant planktonic foraminiferal specimens| and the calcareous nannofossil assemblages continued essentially unchanged into the earliest Eocene Zone NP 10. Within the lower part of Zone NP 10| the kaolinite percentage decreased to very low values. 4026,1993,3,4,LINKED SIMULATION OF LAND-USE AND TRANSPORTATION SYSTEMS - DEVELOPMENTS AND EXPERIENCE IN THE PUGET SOUND REGION,Strategies to reduce motor vehicle travel by altering urban spatial structure are one piece of a comprehensive program to slow global warming. While the connections between urban spatial form and urban travel have long been recognized| there have been few attempts in the United States to model the interactions within the context of a public planning program in an urban region. One such effort| the Vision 2020 plan in the Seattle region| is described in this paper. The modeling tools utilized widely available travel and land-use models| applied interactively. A wide range of variables| consisting of transportation facility investments| demand management measures and land-use controls| were grouped into identifiable long-term alternatives. The analysis suggested some ambiguity in the ability to model the processes| particularly within a highly political planning program| and indicated rather modest effects of land-use changes on reducing urban travel over 20 to 30 years. Land use and demand management were most effective when supported by significant investment in facilities| including transit. Although attempting to alter urban spatial structure may not be the most cost-effective place to seek reductions in vehicular emissions over this period of time| planning programs like Seattle's may be an opportunity to mold less travel-dependent urban regions for the next century. 2664,1993,2,4,LONG-TERM IMPACTS OF FOREST TREATMENTS ON WATER YIELD - A SUMMARY FOR NORTHEASTERN USA,Long-term changes in annual water yield are summarized and compared for 11 catchment studies in the northeastern USA. Substantial increases in water yield of up to 350 mm year-1 were obtained in the first year by clearing forest vegetation and controlling regrowth with herbicides. Commercial clearcutting with natural regrowth resulted in initial increases in water yield of 110-250 mm year-1. This range in response was due to differences in precipitation and configuration of cuttings. Unless regrowth was controlled with herbicides| yield increases declined quickly after cutting| seldom persisting for more than 10 years. However| yield increases were readily extended over 20 years or more with intermediate cuttings and/or repeated control of regrowth with herbicides. Nearly all increases in water yield occur during the growing season as augmentation of baseflow. Changes in species composition after forest cutting on several study catchments eventually resulted in decreased water yields compared with those from uncut| control catchments. Results are discussed in terms of implications for surface water supplies| global climate change| nutrient cycling| hydrological modeling| and long-term research.
4064,1993,2,3,LOW-FREQUENCY VARIABILITY AND CO2 TRANSIENT CLIMATE CHANGE .1. TIME-AVERAGED DIFFERENCES,Results from a global coupled ocean-atmosphere general circulation model (GCM) are used to perform the first in a series of studies of the various time and space scales of climate anomalies in an environment of gradually increasing carbon dioxide (CO2) (a linear transient increase of 1% per year in the coupled model). Since observed climate anomaly patterns often are computed as time-averaged differences between two periods| climate-change signals in the coupled model are defined using differences of various averaging intervals between the transient and control integrations. Annual mean surface air temperature differences for several regions show that the Northern Hemisphere warms faster than the Southern Hemisphere and that land areas warm faster than ocean. The high northern latitudes outside the North Atlantic contribute most to global warming but also exhibit great variability| while the high southern latitudes contribute the least. The equatorial tropics warm more slowly than the subtropics due to strong upwelling and mixing in the ocean. The globally averaged surface air temperature trend computed from annual mean differences for years 23-60 is 0.03-degrees-C per year. Projecting this trend to the time of CO2 doubling in year 100 produces a warming of 2.3-degrees-C. By chance| one particular northern winter five-year average geographical difference pattern in the Northern Hemisphere from the coupled model resembles the recent observed pattern of surface temperature and sea-level pressure anomalies. This pattern is not consistent from one five-year period to the next in any season in the model. However| multidecadal averages in the coupled model show that the North Atlantic warms less than the rest of the high northern latitudes| and recent observations may be a manifestation of this phenomenon. Consistent geographic patterns of climate anomalies forced by increased CO2 in the model are more evident with a longer averaging interval. There is also the possibility that the CO2 climate-change signal may itself be a function of time and space. The general pattern of zonal mean temperature anomalies for all periods in the model shows warming in the troposphere and cooling in the stratosphere. This pattern (or one similar to it taking into account the rest of the trace gases) could be looked for in observations to verify the enhanced greenhouse effect. A zonal mean pattern| however| could prove scientifically satisfactory but of little value to policymakers seeking regional climate-change forecasts. These results from the coupled model underscore the difficulty in identifying a time- and space-dependent ''fingerprint' of greenhouse warming that has some practical use from short climatic records and point to the need to understand the mechanisms of decadal-scale variability. 2690,1993,4,4,MANAGING THE GLOBAL CLIMATE-CHANGE SCIENTIFIC KNOWLEDGE-BASE,Successful problem solving is the key to survival and wealth for individuals| corporations| and nations alike. Successful problem solving depends upon 1) the nature and complexity of the problem to be solved; 2) the accessibility of high quality| relevant knowledge; and 3) a well-led team of effective individuals who can use knowledge wisely. Many centuries of managing our natural resources based on decisions with poorly understood consequences may be changing the climate of our planet. As a response to this threat| many nations have funded an unprecedented scientific research and assessment program which is resulting in a rapidly expanding global climate change knowledge base. Learning how to manage the knowledge that will allow us to successfully solve the global climate change problem is a very important component of the overall research effort. Currently| hypertext appears to offer the most promising electronic technology for general-purpose knowledge management. In this paper| hypertext authoring is described| a pilot study to develop a hypertext scientific assessment of the forest and soil carbon cycle is introduced| and the major research issues that will need to be solved are identified.
4014,1993,2,4,MEASUREMENT OF THE RETREAT OF QORI KALIS GLACIER IN THE TROPICAL ANDES OF PERU BY TERRESTRIAL PHOTOGRAMMETRY,Although the consequences of global warming in the last century may be most pronounced on glaciers of the tropics and subtropics| documentation of their recent retreat is extremely limited. The extent and volume of the largest outlet glacier from the Quelccaya Ice Cap (14-degrees-S| 71-degrees-W| 5200 m above sea level) have been measured four times between 1963 and 1991| once by aerial and three times by terrestrial photogrammetry. Drastic and accelerating rates of retreat of the terminus and of ice volume loss have been documented. The rate of retreat was nearly three times as fast between 1983 and 1991 as between 1963 and 1978 and the rate of volume loss was over seven times as great. These results are consistent with the warming in this region and with the behavior of tropical glaciers in the Cordillera Blanca in Peru and in the Ruwenzori Mountains and on Mount Kenya in East Africa. 4031,1993,3,3,MEMBRANE-DEVELOPMENT FOR THE SEPARATION OF H-2 AND CO2 - SCREENING-TESTS,As a fall-back response to the possibility of Global Warming due lo increasing gases in the atmosphere British Coal is investigating Low-CO2 Power Generation options. One of the most promising options is an Integrated Gasification Combined Cycle (IGCC) system using a membrane separation unit to separate H-2 and CO2. However| the performance requirements cannot be met by currently available commercial membranes. A small-scale membrane permeation test rig has been designed and built at CRE. This paper describes screening tests carried out on polymeric and Pd/Ag alloy membranes. The most promising of these was the Pd/Ag alloy as it did not pass any CO2. Microporous ceramics and thin films of Pd/Ag deposited onto a suitable porous substrate will be tested in the near future. 4075,1993,2,4,METHANE EMISSION FROM ARCTIC TUNDRA,Concerns about a possible feedback effect on global warming following possible increased emissions of methane from tundra environments have lead to series of methane flux studies of northern wetland/tundra environments. Most of these studies have been carried out in boreal sub-Arctic regions using different techniques and means of assessing representativeness of the tundra. Here are reported a time series of CH4 flux measurements from a true Arctic tundra site. A total of 528 independent observations were made at 22 fixed sites during the summers of 1991 and 1992. The data are fully comparable to the most extensive dataset yet produced on methane emissions from sub-Arctic tundra-like environments. Based on the data presented| from a thaw-season with approximately 55% of normal precipitation| a global tundra CH4 source of 18-30 Tg CH4 yr-1 is estimated. This is within the range of 42 +/- 26 Tg CH4 yr-1 found in a similar sub-Arctic tundra environment. No single-parameter relationship between one environmental factor and CH4 flux covering all sites was found. This is also in line with conclusions drawn in the sub-Arctic. However| inter-season variations in CH4 flux at dry sites were largely controlled by the position of the water table| while flux from wetter sites seemed mainly to be controlled by soil temperature. 2701,1993,3,4,METHANE FROM BIOMASS SYSTEMS-ANALYSIS AND CO2 ABATEMENT POTENTIAL,A mathematical model of terrestrial biomass biogasification is presented. This model calculates mass and energy balances and the levelized cost of synthetic natural gas (SNG). It consists of interconnected modules for harvesting| biomass transportation| biogasification| gas processing| energy balance| global climate change| and economics. The conversion module incorporates bioconversion technology recently developed at pilot scale at Cornell University and Walt Disney World. In large-scale biomass biogasification| in any climate at any reactor temperature| process heat needs are small and could be reduced to zero if metabolic heat production is included. Therefore| thermophilic digestion should be preferred to mesophilic| to the extent that the former results in higher reaction rates. Preliminary sensitivity analyses were conducted. Economies of scale are described. Increases in biomass productivity yield diminishing returns above 45-55 Mg/ha year (20-25 dry tons/ac). Distribution of fields around the conversion facility is unimportant as long as at least thirty percent of the surrounding area is planted in energy crops. Improvements in methane yield result in continuing returns| confirming the importance of this parameter. Only a minor penalty is incurred for overdesigning the retention time up to fifty percent; such overdesign would greatly enhance reliability. The research state-of-the-art is slightly above $6/GJ (MMBtu). Sale of coproducts could reduce this cost in half. The potential impact of energy crops on global climate change is quantified.
4072,1993,2,4,METHANE IN PERMAFROST - PRELIMINARY-RESULTS FROM CORING AT FAIRBANKS| ALASKA,Permafrost has been suggested as a high-latitude source of methane (a greenhouse gas) during global warming. To begin to assess the magnitude of this source| we have examined the methane content of permafrost in samples from shallow cores (maximum depth| 9.5 m) at three sites in Fairbanks| Alaska| where discontinuous permafrost is common. These cores sampled frozen loess| peat| and water (ice) below the active layer. Methane contents of permafrost range from < 0.001 to 22.2 mg/kg of sample. The highest methane content of 22.2 mg/kg was found in association with peat at one site. Silty loess had high methane contents at each site of 6.56| 4.24| and 0.152 mg/kg| respectively. Carbon isotopic compositions of the methane (deltaC-13) ranged from -70.8 to -103.9 parts per thousand| and hydrogen isotopic compositions of the methane (deltaD) from -213 to -313 parts per thousand| indicating that the methane is microbial in origin. The methane concentrations were used in a one dimensional heat conduction model to predict the amount of methane that will be released from permafrost worldwide over the next 100 years| given two climate change scenarios. Our results indicate that at least 30 years will elapse before melting permafrost releases important amounts of methane; a maximum methane release rate will be about 25 to 30 Tg/yr| assuming that methane is generally distributed in shallow permafrost as observed in our samples. 4000,1993,4,2,MODEL SIMULATIONS OF THE COMPETING CLIMATIC EFFECTS OF SO2 AND CO2,Sulfur dioxide-derived cloud condensation nuclei are expected to enhance the planetary albedo| thereby cooling the planet. This effect might counteract the global warming expected from enhanced greenhouse gases. A detailed treatment of the relationship between fossil fuel burning and the SO2 effect on cloud albedo is implemented in a two-dimensional model for assessing the climate impact. Although there are large gaps in our knowledge of the atmospheric sources and sinks of sulfate aerosol| it is possible to reach some general conclusions. Using a conservative approach| results show that the cooling induced by the SO2 emission can presently counteract 50% of the CO2 greenhouse warming. Since 1980| a strong warming trend has been predicted by the model| 0.15-degrees-C| during the 1980-1990 period alone. The model predicts that by the year 2060 the SO2 cooling reduces climate warming by 0.5-degrees-C or 25% for the Intergovernmental Panel on Climate Change (IPCC) business as usual (BAU) scenario and 0.2-degrees-C or 20% for scenario D (for a slow pace of fossil fuel burning). The hypothesis is examined that the different responses between the Northern Hemisphere (NH) and the Southern Hemisphere (SH) can be used to validate the presence of the SO2-induced cooling. Despite the fact that most of the SO2-induced cooling takes place in the Northern Hemispheric continents| the model-predicted difference in the temperature response between the NH and the SH of -0.2-degrees-C in 1980 is expected to remain about the same at least until 2060. This result is a combined effect of the much faster response of the continents than the oceans and of the larger forcing due to CO2 than due to the SO2. The climatic response to a complete filtering of SO2 from the emission products in order to reduce acid rain is also examined. The result is a warming surge of 0.4-degrees-C in the first few years after the elimination of the SO2 emission. 4063,1993,2,4,MODELING EFFECTS OF HABITAT FRAGMENTATION ON THE ABILITY OF TREES TO RESPOND TO CLIMATIC WARMING,The ability of trees to migrate in response to climatic warming was simulated under various conditions of habitat availability. The model uses Holocene tree migration rates to approximate maximum migration rates in a forested landscape. Habitat availability and local population size was varied systematically under two dispersal and colonization models. These dispersal models varied in the likelihood of long-distance dispersal events. The first model used a negative exponential function that severely limited the probability of long-distance dispersal. The results of this model indicate that migration rate could decline an order of magnitude where the habitat availability is reduced from 80 to 20% of the matrix. The second model| using an inverse power function| carried a higher probability of long-distance dispersal events. The results from this model predict relatively small declines in migration rates when habitat availability is reduced to 50% of the simulation matrix. Below 50% habitat availability| mean migration rate was similar to the negative exponential model. These results predict a failure of many trees to respond to future climatic change through range expansion. 4021,1993,4,4,MODELING SUB-ALPINE FOREST DYNAMICS AS INFLUENCED BY A CHANGING ENVIRONMENT,FORSUM| a forest succession model of the JABOWA/FORET type was applied to simulate possible impacts of environmental changes on subalpine forest ecosystems and compared with the model FORECE (Kienast| 1987). The model used is based on approaches of Botkin et al. (1972)| Shugart (1984) and Kienast (1987) and has been improved by implementing soil water movement calculations based on a user-defined one-dimensional nonhomogeneous soil profile. The influence of a possible climatic change on subalpine ecosystems was investigated for three different sites in the Grisons (Switzerland). The scenarios used are based on climate change predictions of General Circulation Models. A temperature increase of 3-degrees-C would cause important changes in species composition. Deciduous trees would invade today's subalpine belt causing a displacement of various conifers in this zone. Some coniferous species might eventually migrate into today's alpine zone which would consequently become afforested. Comparing the vegetation changes as predicted by the model FORSUM and FORECE we found that the models generate the main general patterns. However under global warming and a concurrent precipitation decrease total biomass production seems to be overestimated by FORECE. Information about seed dispersal rates (horizontal and vertical)| seed availability and soil formation processes should be implemented in these models to improve the reliability of the predictions. 3947,1993,4,4,MODELING THE PRODUCTION OF DIMETHYLSULFIDE DURING A PHYTOPLANKTON BLOOM,Dimethylsulfide (DMS) is an important sulfur-containing atmospheric trace gas of marine biogenic origin. DMS emitted from the oceans may be a precursor of tropospheric aerosols and cloud condensation nuclei (CCN)| thereby affecting the Earth's radiative balance and possibly constituting a negative feedback to global warming| although this hypothesis is still somewhat controversial. The revised conceptual model of the marine pelagic food web gives a central role to planktonic bacteria. Recent experiments have shown that consumption of dissolved DMS by microbial metabolism may be more important than atmospheric exchange in controlling its concentration in surface waters and hence its ventilation to the atmosphere. In this paper we investigate the effect of the marine food web on cycling of dissolved DMS in surface waters during a phytoplankton bloom episode. A nitrogen-based flow network simulation model has been used to analyze the relative importance of the various biological and chemical processes involved. The model predictions suggest that the concentration of DMS in marine surface waters is indeed governed by bacterial metabolism. Environmental factors that affect the bacterial compartment are thus likely to have a relatively large influence on dissolved DMS concentrations. The ecological succession is particularly sensitive to the ratio of phytoplankton to bacterial nutrient uptake rates as well the interaction between herbivore food chain and the microbial loop. Importantly for the design of field studies| the model predicts that peak DMS concentrations are achieved during the decline of the phytoplankton bloom with a typical time lag between peak DMS and peak phytoplankton biomass of 1 to 2 days. Significantly| the model predicts a relatively high DMS concentration persisting after the phytoplankton bloom due to excretion from large protozoa and zooplankton| which may be an additional ''planation for the lack of correlation between DMS and chlorophyll a field measurements. Comparison of the model predictions has been made with tank algal bloom experiments. 4093,1993,4,4,MOS-1/MOS-1B/ERS-1/JERS-1 DATA SETS OF SEA-SURFACE TEMPERATURE AND POLAR ICE EXTENT FOR ISY,Human beings face serious earth environment problems. In order to resolve such problems| it is necessary to observe the earth and produce several data sets using satellite and auxiliary data. As a part of ISY and verification activity| NASDA has developed various data sets using MOS-1/MOS-1b/ERS-1/JERS-1 data particularly for sea surface temperature and polar ice extent which are indicators of global warming. In this gaper| outline of these data sets for sea surface temperature and polar ice extent is presented. 4023,1993,3,3,MULTICRITERIA GENERATION-EXPANSION PLANNING WITH GLOBAL ENVIRONMENTAL CONSIDERATIONS,This paper discusses the multicriteria capacity-mix problem of electric utilities. Traditional least-cost generation-expansion planning has become inadequate due to the prevailing multiple| conflicting objectives such as cost| environmental degradation| and nuclear hazards. This particularly true with emerging concerns over carbon dioxide emissions that are believed to contribute to global warming. In this paper we present the preference-order dynamic programming approach| so that this new logic can be implemented with the already available dynamic-programming-based capacity-expansion planning tool| called Wien Automatic System Planning Package (WASP). Through our case study| we note the importance of considering global warming as well as nuclear hazards. We also note that substituting plants that use cleaner fuels such as natural gas for those that use carbon-intensive fuels such as coal is more effective in controlling carbon dioxide emissions. This substitution method is also more effective than replacing these plants with carbon dioxide-free nuclear units. 4089,1993,3,3,NEW POWER-PRODUCTION TECHNOLOGIES - VARIOUS OPTIONS FOR BIOMASS AND COGENERATION,Bioenergy will be the most significant renewable energy source in the next few decades until solar- or wind-power production offers an economically attractive large-scale alternative. Structural changes are required in power production in the near future owing to concern for global warming. Separate power production from fossil fuels should be replaced as extensively as possible by a new highly efficient power-generation structure. In Scandinavia| as well as to some extent elsewhere in Europe| combined heat and power production (CHP) is widely used and is an efficient way to reduce CO2 emissions. In CHP| the additional power capacity can be produced by using IGCC and diesel techniques| and a potentially double amount of electricity is obtained with a constant hear load The Finnish JALO research programme focuses on these techniques in a wide spectrum of the thermochemical conversion programme. Basic and applied research as well as pilot activities has been carried out in research organizations and in industry in Finland. A sum of about ECU 9 million has been invested in the programme over the past five years. The first pilot and demonstration plants with solid-biomass IGCC technology will be put into operation by private enterprises in 1993. If the price of biofuels is competitive| these new technologies will probably be commercialized by the end of the 1990s. International co-operation within ECE JOULE and IEA has played an important role in the JALO programme. 2694,1993,4,4,NITROGEN BIOGEOCHEMICAL CYCLING IN THE NORTHWESTERN INDIAN-OCEAN,The vertical distribution and fine scale structure of nitrate (NO3)| nitrite (NO2)| nitrous oxide (N2O)| phosphate (PO4)| oxygen (02) and chlorophyll a (chl a) were determined in the North Western Indian Ocean (NWIO) along a meridional section (67-degrees-E) from the Equator to the Gulf of Oman using an Autoanalyser for micromolar levels of nutrients| and chemiluminescence and gas chromatographic methods for nanomolar levels of NO3 and NO2 and N2O respectively. Three biogeochemically contrasting regimes were investigated: (1) the highly oligotrophic nutrient-depleted subtropical gyre; (2) the monsoonal upwelling of nutrient-rich intermediate waters off the southeastern Arabian Coast; and (3) the denitrifying 02-depleted zone (ODZ; ca 150-1200 m depth) in the Arabian Sea. Concentrations of NO3 and NO2 were severely depleted in surface oligotrophic waters from the equator (average 43 and 3.6 nM respectively) to the subtropical gyre (12-15-degrees-N; average 13.3 and 2.0 nM respectively) with similar levels in the more stratified Gulf of Oman. Upwelling waters off Southern Arabia had three orders of magnitude higher NO3 levels| and throughout the NWIO| the calculated NO3-fuelled primary production appeared to be regulated by NO3 concentration. Existing Redfield DELTAO2/DELTANO3 regeneration ratios (=9. 1) previously derived for the deep Indian Ocean were confirmed (=9.35) within the oxic upper layers of the NWIO. The ''NO''-potential temperature relationship (BROECKER| 1974| Earth and Planetary Science Letters| 23| 100-107) needed for the derivation of expected NO3 and NO3-deficits within the denitrifying ODZ were refined using an isopycnal| binary mixing model along the sigma(theta) = 26.6%. density layer to take into account the inflowing contribution of NO3-depleted Persian Gulf Water. Vertically integrated NO3-deficits increased northwards from 0.8 mol NO3-N m-2 at Sta. 2 (04-degrees-N)| up to 6.49 mol NO3-N m-2 at Sta. 9| at the mouth of the Gulf of Oman| then decreased to 4. 10 moles NO3 -N m-2 toward Sta. 11| near the Straits of Hormuz. When averaged for the denitrification area of the Arabian Sea| this corresponds to a deficit of 118 Tg NO3-N. Adopting a recent Freon-11 based estimate of water residence time of 10 years (OLSON et al.| 1993| Deep-Sea Research II| 40| 673-685) for the O2-depleted layer| we calculate an annual net denitrification flux of 11.9 Tg N to the atmosphere or approximately 10% of the global water column denitrification rates. Supersaturated N2O concentrations were found in both surface oxic and upwelling waters (up to 246%) and peaked at the base of the ODZ (up to 1264%) in the northern Arabian Sea. Both nitrification in oxic waters and denitrification in hypoxic layers can be invoked as sources of N2O. The inventory of excess N2O amounted to 2.55 +/- 1.3 Tg N2O-N| corresponding to annual production of 0.26 +/- 0.13 Tg from denitrification. This is comparable to earlier (LAW and OWENS| 1990| Nature| 346| 826-828) estimates of the ventilation flux of N2O (0.22-0.39 Tg yr-1) from the upwelling region of the Arabian Sea. The decadal response times for circulation| deoxygenation| denitrification and ventilation of the ODZ-derived N2O and CO2 greenhouse gases and their monsoonal coupling implies the Arabian Sea is a sensitive oceanic recorder of global climate change.
2672,1993,4,4,NUMERICAL-MODELS OF WEATHER AND CLIMATE,Numerical weather prediction has provided routine forecasts of global weather for more than thirty years. During that period numerical models have evolved from the use of low resolution balance equations to high resolution fluid dynamics equations with added terms to describe physical processes such as radiative heating and latent heat release. Both grid-point and spectral transform methods have been used. Forecasts require an initial state| and much effort has gone into data assimilation and initialization consistent with the nonlinear dynamics of the models. As is well known| the chaotic atmosphere is of limited predictability| and deterministic forecasts axe only good for about a week. The climate is defined by the statistical properties of the weather| and these change far more slowly. There is much current interest in the response of climate to human influences. Global climate change studies are largely based on weather models of lower resolution that are run for much longer times and averaged. But the search continues for a true climate model that deals directly with slowly evolving statistics.
3951,1993,2,4,OBJECTIVE IDENTIFICATION OF CYCLONES IN GCM SIMULATIONS,An objective routine for identifying individual cyclones has been developed. The procedure was designed with the aim to keep the input expenditure low: The method ensures a complete collection of cyclones and an exclusion of short time fluctuations attributed to numerical effects. The cyclones are identified as relative minima of the geopotential height field in 1000 hPa. The initial stages of the cyclones are found by locating relative maxima in the 850-hPa vorticity field. Further on the temporal development of the extrema is taken into consideration. An individual cyclone is regarded only if it exists for at least 24 h and if it attains a mature stage at least once| where a certain margin of the geopotential gradient to the surroundings is exceeded. The identification routine is applied to simulations with the Hamburg general circulation model ECHAM in T21 resolution. Also| cyclone tracks based on ECMWF analyses are evaluated| to which the model results are compared. The effect of different climate conditions| for example| global warming| on cyclone frequency and track location is investigated. It is found that a warmer SST distribution leads to a slight reduction of cyclone frequency in the Southern Hemisphere in fall (March| April| May) and winter (June| July| August); elsewhere the differences are not significant. 3961,1993,4,3,ON THE COLD START PROBLEM IN TRANSIENT SIMULATIONS WITH COUPLED ATMOSPHERE-OCEAN MODELS,Finite computer resources force compromises in the design of transient numerical experiments with coupled atmosphere-ocean general circulation models which| in the case of global warming simulations| normally preclude a full integration from the undisturbed pre-industrial state. The start of the integration at a later time from a climate state which| in contrast to the true climate| is initially in equilibrium then induces a cold start error. Using linear response theory a general expression for the cold start error is derived. The theory is applied to the Hamburg CO2 scenario simulations. An attempt to estimate the global-mean-temperature response function of the coupled model from the response of the model to a CO2 doubling was unsuccessful because of the non-linearity of the system. However| an alternative derivation| based on the transient simulation itself| yielded a cold start error which explained the initial retardation of the Hamburg global warming curve relative to the IPCC results obtained with a simple box-diffusion-upwelling model. In the case of the sea level the behaviour of the model is apparently more linear. The cold start error estimations based on a CO2 doubling experiment and on an experiment with gradually increasing CO2 (scenario A) are very similar and explain about two thirds of the coupled model retardation relative to the IPCC results. 4002,1993,3,3,OPPORTUNITIES FOR DEVELOPING SPECIALTY CHEMICALS AND ADVANCED MATERIALS FROM COALS,The main objective of this paper is to explore the potentials and possible ways to develop high-value chemicals and materials from coals and coal liquids. Recently it has become clear that more extensive use of fossil fuels| especially coal| may be constrained not only by economics| but also by environmental considerations such as SO(x) and NO(x) emissions and global warming. Therefore| new concepts are required| and significant advances are essential for the effective utilization of coals in the next century. Both from economic and environmental viewpoints| developing high-value chemicals and materials from coals and coal liquids should lead to more efficient and environmentally safe utilization of the valuable carbonaceous resources. It is important to explore the routes and methods for developing specialty chemicals| which are difficult to obtain or not readily available from petroleum| advanced polymeric engineering materials| and high-performance carbon materials. Recent years have seen significant progress in the development and application of new| industrially important aromatic engineering plastics| thermoplastic materials| liquid crystalline polymers| and membrane materials. Many of the monomers for these materials can be prepared from one- to four-ring aromatics such as alkylated benzenes| naphthalene| biphenyl| anthracene| phenanthrene| pyrene| phenol| and carbazole. Especially important are 2|6-dialkylnaphthalenes| 4|4'-dialkylbiphenyls| and 1|4-dialkylbenzenes. The large-volume application of aromatic high-performance polymers depends on lowering their cost| which in turn is largely determined by the cost of the aromatic monomers. By developing the critical aromatic chemicals from coals| coal-to-chemicals research could contribute significantly to high-technology development. Potential large-volume markets for materials from coal can be stimulated by developing high-performance carbon materials such as carbon fibers and graphites| and by developing ways to make advanced adsorbents for environmental applications such as air and water purification. 3991,1993,5,3,PALEOATMOSPHERIC CONSEQUENCES OF CO2 RELEASED DURING EARLY CENOZOIC REGIONAL METAMORPHISM IN THE TETHYAN OROGEN,The Eocene was the warmest epoch of the Cenozoic| with published estimates of Eocene atmospheric CO2 content ranging from two to six times the current value. Calculations of CO2 consumption by silicate weathering show that CO2 fluxes to the atmosphere of ca. 10(18)/Myr could account for inferred Paleocene/Eocene atmospheric CO2 contents| and the resulting greenhouse effect would have contributed to Eocene warmth. Extensive portions of the Tethyan orogen underwent regional metamorphism culminating in the Eocene. Prograde metamorphism may have been contemporaneous with the Late Paleocene global warming. We calculated the amount of metamorphic CO2 produced at depth in the Himalayan orogen with data on the timing of the India/Asia collision| duration of prograde regional metamorphism| and proportions and bulk compositions of metamorphic CO2 source rocks. If CO2 was generated at a constant rate over a 10 Myr period of prograde metamorphism in the Himalayan orogen| we estimate that ca. 10(18)-10(19) moles/Myr of metamorphic CO2 were produced al depth. Significant expulsion of metamorphic CO2 to the atmosphere may have occurred by focused fluid flow along shear zones such as the extensive Main Central Thrust in the Himalayan orogen. An additional ca. 10(18)/Myr could have been contributed by Eocene regional metamorphism in the Mediterranean Tethys (i.e.| from the Alps to Turkey). The extensive metamorphism associated with the India/Asia collision| and the closing of Tethys| may have contributed to CO2-greenhouse warming in the early to mid Cenozoic. 3988,1993,5,3,PALEOECOLOGY| PAST CLIMATE SYSTEMS| AND C3/C4PHOTOSYNTHESIS,The geologic record shows unequivocally that the present world is unusually cold; the so called 'greenhouse' condition has been normal for planet Earth for the past 500 million years. Continental positions| orbital parameters| and atmospheric composition strongly influence global climate on timescales ranging from 10(8) to 10(2) years. Atmospheric CO2 is an important contributing factor in determining average global temperature| and is particularly important in influencing changes over shorter timescales (say < 10(5) years). Carbon sequestering on land has varied substantially over the past 500 million years and may be correlated with changing climate. Most terrestrial carbon sequestering operates on biological timescales (<10(5) years) rather than geological timescales (>10(5) years). Terrestrial carbon sequestering is strongly influenced by the biology of the organisms involved and it has been shown that terrestrial carbon sequestering is greater in ever-wet conditions. The distribution of the sites of greatest carbon sequestering switches from low latitudes during icehouse times to higher latitudes| >40-degrees| during greenhouse times| except maritime sites. Evolutionary factors| e.g. competition| and climate change have led to major ecosystem restructuring during the past 500 million years. Pre-change biodiversity is therefore critical in determining the nature and rate of restructuring particularly with respect to plants which are the only group of organisms capable of carbon sequestering. There exists a number of uncertainties as well as probabilities involved in estimating sequestering ratios and climate changes; Estimates of past carbon sequestering are likely to be too low because dispersed fossil organic matter is inadequately inventoried. Numerical climate model results are unreliable unless evaluated against fossil and sediment data. Terrestrial carbon sequestering is unlikely to dominate tectonic controls but as it operates on a shorter time scale it has a strong short term effect and could well tip the climate balance in critical situations. Most extant land plants have a C3 photosynthetic pathway. However| under conditions where photorespiration can reduce photosynthetic efficiency| warmth and high O2 concentrations| many unrelated plants have independently evolved C4 pathways. C4 plants have different water relations and competitive characteristics to C3 plants and clearly ecosystem structure and carbon sequestering are likely to change with global warming. By studying the different isotopic signature bequeathed by these systems the fossil record can provide critical data on the dynamics of plants with these systems under changing climatic conditions: data that again are essential for effective ecosystem management strategies. 2675,1993,5,3,PALEOZOIC ATMOSPHERIC CO2 - IMPORTANCE OF SOLAR-RADIATION AND PLANT EVOLUTION,Changes in solar radiation| as it affects the rate of weathering of silicates on the continents| and other changes involving weathering and the degassing of carbon dioxide (CO2) have been included in a long-term carbon-cycle model. These additions to the model show that the major controls on CO2 concentrations during the Paleozoic era were solar and biological| and not tectonic| in origin. The model predictions agree with independent estimates of a large mid-Paleozoic (400 to 320 million years ago) drop in CO2 concentrations| which led to large-scale glaciation. This agreement indicates that variations in the atmospheric greenhouse effect were important in global climate change during the distant geologic past.
4004,1993,5,4,PLUVIAL CONDITIONS IN THE EASTERN SAHARA FOLLOWING THE PENULTIMATE DEGLACIATION - IMPLICATIONS FOR CHANGES IN ATMOSPHERIC CIRCULATION PATTERNS WITH GLOBAL WARMING,During the transition from the penultimate glacial to the last interglacial period (Isotope Stages 6-5e or Terminal II)| large freshwater lakes abruptly infilled sandy depressions in arid regions of the eastern Sahara. Geochemical and mineralogical studies of samples from lacustrine sequences in the Western Desert of southern Egypt indicate: (1) The sediments are chalk composed of authigenic chemical precipitates| predominantly low-Mg calcite| with carbonate contents averaging about 80%. The low dilution of the chemical precipitate by detrital input implies that physical erosion and transport of detrital grains were minimized by extensive vegetation cover in the catchment area. The fauna and flora associated with the lake deposits and Middle Paleolithic occupation sites on the paleo-shorelines attest to a more amenable environment. (2) Vastly different rainfall or atmospheric circulation patterns than at present must have existed based on consistently negative deltaO-18PDB values for the chalk| as low as -9.5 parts per thousand| which would require precipitation from lake waters significantly more depleted in O-18 than the modern local spring water (deltaO-18SMOW= -1.8 parts per thousand). (3) The lakes were stable perennial water bodies with relatively long residence times sufficient to produce isotopic covariant signals in the chalks. Apparently| the lakes disappeared as abruptly as they appeared without going through a terminal phase of evaporative enrichment. Extremely arid conditions again prevailed. During the transition from the last glacial to the present interglacial (Terminal 1)| a similar change from arid to pluvial conditions occurred. Thus| it is proposed that| during transitions from glacial to interglacial climates| rapid global warming can lead to a temporary alteration of atmospheric circulation with an intensification of the southwest monsoons| bringing large quantities of isotopically light moisture to the Eastern Sahara. 4045,1993,3,3,POLICY ANALYSIS OF THE GREENHOUSE-EFFECT - AN APPLICATION OF THE PAGE MODEL,In this paper we introduce a comprehensive model for policy analysis of the greenhouse effect (PAGE). We apply the PAGE model to assess the merits of policies to prevent global warming (by controlling the emissions of greenhouse gases)| and policies to adapt to any global warming that occurs. The results confirm that it is difficult to overcome the problem of global warming by taking preventive action alone. The argument for introducing an aggressive adaptive policy is very strong. We calculate the valuation that would have to be placed upon non-economic environmental and social impacts| for a combined strategy of preventive and adaptive policies to be considered a worthwhile option| both for individual regions and for the world as a whole. We also show that uncertainties in all four groups of inputs to the model (scientific| costs of control| costs of adaptation and valuation of impacts) have a great influence on the costs and im acts of the combined strategy. 3963,1993,3,4,POLYURETHANES AND THE ENVIRONMENT,Recent developments in polyurethane foams show that CFCs can be phased out almost completely| now. In applications where ozone-depleting CFCs served solely to expand the reaction mix| they have long since been replaced. And alternative products are now available for use in insulating foams| where CFC gas is retained in the cells to create the thermal insulation. Polyurethanes have long been recognised as highly effective| energy-saving insulants in the building industry and in technical insulation. They also help to reduce weight and material usage in automotive construction. In this way they play an important part in conserving scarce resources and reducing emissions| Polyurethanes are chemically crosslinked polymers which| unlike thermoplastics| cannot simply be melted down for reuse at the end of their first useful life. Various technologies for recycling polyurethanes are available| including material and chemical recycling and recovery of the energy content The most suitable method has to be determined in each individual case. 2662,1993,3,3,POOLS AND FLUXES OF BIOGENIC CARBON IN THE FORMER SOVIET-UNION,The Former Soviet Union (FSU) was the largest country in the world. It occupied one-sixth of the land surface of the Earth. An understanding of the pools and fluxes of biogenic C in the FSU is essential to the development of international strategies aimed at mitigation of the negative impacts of global climate change. The territory of the FSU is represented by a variety of climate conditions. The major part of the FSU territory is in the boreal and temperate climatic zones. The climate in the FSU changes from arctic and subarctic in the North to subtropical and desert in the South. From west to east| the climate makes a transition from maritime to continental to monsoon. The vegetation of the FSU includes the following principal types: forest| woodland| shrubland| grassland| tundra| desert| peatlands and cultivated land. Arctic deserts and tundra formations are found in the northern part of the FSU; deserts and semi-deserts are found in the southern part. A framework was created to assess pools and fluxes of biogenic C in the FSU. Under the framework spatially distributed data were analyzed with a geographic information system to isolate ecoregions. The soil-vegetation complexes for the ecoregions were linked to FSU data bases of soil and vegetation C pools and fluxes. The C budget for an ecoregion was established by multiplying the area of the ecoregion by the unit area C content(s) or rate(s) associated with the soil-vegetation complex for the ecoregion. The C pools and fluxes for all the ecoregions were summed to arrive at an initial estimate of the pools and fluxes of biogenic C for 95% of the territory of the FSU. Based on the framework| net primary productivity (NPP) for the FSU was estimated at 6.17 +/- 1.65 Gt C yr-1| the vegetation C pool (live plant mass and coarse woody debris) at 118.1 +/- 28.5 Gt C| the litter C pool at 18.9 +/- 4.4 Gt C| and total soil C pool at 404.0 +/- 38.0 Gt C. The phytomass pool of the FSU was 16% of the global biomass pool. The soil and litter pools of the FSU were 20 and 23% of the global soil and detritus pools| respectively. The NPP of the FSU was 10% of the global NPP. The phytomass| soil and litter densities of the FSU were greater than the world average. The productivity of terrestrial ecosystems in the FSU was slightly lower than the world average.
3949,1993,2,4,POSTFIRE VEGETATION RECOVERY AND TREE ESTABLISHMENT AT THE ARCTIC TREELINE - CLIMATE-CHANGE VEGETATION-RESPONSE HYPOTHESES,1 A fire of unusually great severity (deep burning) burned across the forest-tundra ecotone near Inuvik| Northwest Territories from August 8 to 18| 1968. 2 Burned-unburned paired study sites around the fire perimeter| which had been established in both tundra and forest-tundra in 1973 were relocated in 1990. These showed that total vascular plant cover had reached prefire levels after 22 years| that tall shrubs had become dominant in the tundra and that biomass was now sufficient to support another fire. Cryptogams showed minimum recovery between the two studies. 3 In previously treed areas postfire densities of Picea mariana and Picea glauca were much lower than before. Betula papyrifera and Populus balsamifera| however| showed an increase in density and had extended their range into previously treeless areas. 4 The results obtained have implications for vegetation changes in the Circumpolar North related to global warming. It is predicted that deciduous tree species with long distance seed dispersal mechanisms will increase in abundance and will invade the tundra in a stepwise fashion after each fire. This will be most noticeable near northward flowing rivers because these valleys provide the habitat for outlier tree populations and are therefore a major source of propagules. 3946,1993,3,4,POTENTIAL CHLOROFLUOROCARBON REPLACEMENTS - OH REACTION-RATE CONSTANTS BETWEEN 250 AND 315-K AND INFRARED-ABSORPTION SPECTRA,We measured the rate constant for reactions of the OH radical with several potential chlorofluorocarbon replacements over the temperature range 251-314 K using laser photolysis laser-induced fluorescence techniques. The compounds studied and Arrhenius parameters determined from fits to the measured rate constants are as follows: CHF2OCHF2 (E 134)| k(T) = (5.4 +/- 3.5) x 10(-13) cm3 s-1 exp [(-3.1 +/- 0.4 kcal mol-1)/RT]; CF3CH2CF3 (FC 236fa)| k(T) = (2.0 +/- 1.0) X 10(-14) CM3 S-1 exp [(-1.8 +/- 0.3 kcal mol-1)/RT]; CF3CHFCH2F2 (FC 236ea)| k(T) = (2.0 +/- 0.9) X 10(-13) CM3 S-1 exp [(-2.0 +/- 0.3 kcal mol-1)/RT]; and CF3CF2CH2F (FC 236cb)| k(T) = (2.6 +/- 1.6) X 10(-13) cm3 S-1 exp [(-2.2 +/- 0.4 kcal mol-1)/RT]. The measured activation energies (2-3 kcal mol-1) are consistent with a mechanism of H atom abstraction. The tropospheric lifetimes| estimated from the measured OH reaction rates| and measured integrated infrared absorption cross sections over the range 770 to 1430 cm-1 suggest that E 134 and FC 236fa may have significant global warming potential. while FC 236ea and FC 236cb do not. 4027,1993,3,3,POTENTIAL CONTRIBUTIONS OF INTELLIGENT VEHICLE HIGHWAY SYSTEMS (IVHS) TO REDUCING TRANPORTATIONS GREENHOUSE GAS-PRODUCTION,The road transportation system (including automobiles| buses and trucks) has not yet made significant use of modern electronics technologies to enhance system operations. Intelligent vehicle/highway systems (IVHS) is the label currently applied to the nascent attempts to use advanced technologies to enable travelers| vehicles and the roadway infrastructure to function as an integrated system. IVHS technologies influence both the supply and demand sides of transportation| to promote enhanced operational efficiency and reductions in vehicle miles traveled. These changes can reduce the contribution of the transportation sector to global warming in ways that are explained qualitatively in the paper. Quantitative evaluation of the global-warming implications of IVHS must follow from further research on the technology and travelers' responses to it| and from development of the policy framework for IVHS implementation. 2678,1993,2,3,POTENTIAL EFFECTS OF CLIMATE-CHANGE ON A SEMI-PERMANENT PRAIRIE WETLAND,We assessed the potential effects of a greenhouse gas-induced global climate change on the hydrology and vegetation of a semi-permanent prairie wetland using a spatially-defined| rule-based simulation model. An 11-yr simulation was run using current versus enhanced greenhouse gas climates. Projections of climatic change were from the Goddard Institute for Space Studies (GISS) general circulation model. Simulations were also run using a range of temperature (+2 and +4-degrees-C) and precipitation change values (-20| -10| 0| +10| +20%) to determine the responsiveness of wetland vegetation and hydrology to a variety of climate scenarios. Maximum water depths were significantly less under the enhanced greenhouse gas scenario than under the current climate. The wetland dried in most years with increased temperature and changes in precipitation. Simulations also revealed a significant change in the vegetation| from a nearly balanced emergent cover to open water ratio to a completely closed basin with no open water areas. Simulations over a range of climate change scenarios showed that precipitation changes (particularly increases) had a greater impact on water levels and cover ratios when the temperature increase was moderate (+2-degrees-C). These potential changes in wetland hydrology and vegetation could result in a dramatic decline in the quality of habitat for breeding birds| particularly water-fowl. Continued research on climate and wetland modeling is needed.
3987,1993,3,2,POTENTIAL LIMITS OF HUMAN DOMINATED FOSSIL ENERGY-BASED GLOBAL ECOSYSTEMS,Presently atmospheric carbon dioxide (CO2) content is rising in a sustained manner faster than at any time in the recent past (150|000 years) for which we have well documented information Carbon dioxide is also rising even faster than at any time in the past 500 million years. The present sharp rise in CO2| driven mainly by the comparatively rapid combustion of fossil carbon representing the energy deposits arising from slow accumulation from the ecosystems of bygone ages| is expected to have profound effects on the present and future global climate as well as on natural ecosystems| their associated biodiversity and current patterns of agricultural production. However| there exists an even more serious facet to the problem posed by the necessity to control increasing CO2 and associated global warming and that is the loss of biodiversity (ecosystems| habitats| and species)| resulting from the fact that climatic change and biological diversity are intimately inter-linked. Plants are the only organisms capable of removing significant amounts of CO2 from the atmosphere. It is now certain that natural responses for sequestering carbon have been outstripped| therefore humankind will be forced to accelerate the biosphere adjustment processes| i.e. massive reforestation programs and ecosystem engineering in order to buffer atmospheric CO2. A significant part of this atmospheric carbon was| until recently| sequestered into oil and coal by biological and geological action. Currently| mainly due to industrialization| man is pumping sequestered carbon back into the atmosphere at a rate faster than the present distribution of ecosystems| including agricultural crops| can absorb and is therefor largely responsible for the ''greenhouse effect''. Moreover| most prehistoric global ecological changes occurred slowly| probably over millions of years and vegetation had sufficient time to either move or adapt. Present changes are expected to include an increase in the average temperature (which will not necessarily be evenly distributed)| a subsequent rise of sea level and the redistribution of precipitation. These changes will occur in less than the lifetime of an average tree. It is probable that many species will not have the necessary time to adjust and will perish as their habitats disappear and vegetation belts change. Over 50% of the original forest biomass covering the globe before the advent of modern civilization has already been removed and replaced by human habitats and associated agricultural systems. Even simple solutions to the problem of sequestering carbon through traditional mono-culture plantation developments are no longer tenable because of the excessive geographical areas that would be involved. 4034,1993,2,3,PREDICTING BIOLOGICAL RESPONSE TO GLOBAL WARMING - A LABORATORY ACTIVITY TO PROMOTE DISCUSSION,A measured rise in the carbon dioxide content of the atmosphere is expected to have a significant impact on the Earth's climate and biota. Within the next 50 years the average global temperatureis predicted to rise from 0.80F to 2.50F(1.5Cto 4.5C)(Jager 1988;Houghton et al. 1990 as cited by Ojimaet al. 1991) due to a phenomenon called the "greenhouse effect." That is| while CO2 and other atmo- spheric gases readily permit shorter| solar wavelengths to penetrate to the Earth| they trap longer| re-radiated wavelengths from the Earth| causing atmospherictemperatureto rise. Presently| teams of scientists are working on complicated computer models to predict changes in global temperature and precipitation (Bolin et al. 1986; Ojimaet al. 1991). Articles discussing the impacts of changes in temperature and precipitation on global and regional scales are frequent in the popular press (Nash 1987; Pain 1988; Revkin 1988; Adler & Hager 1988).
3990,1993,2,3,PREDICTING THE EFFECTS OF GLOBAL WARMING ON TERRESTRIAL ECOSYSTEMS BY CHARBON CYCLE MODEL,The effect of climate change by the increase of atmospheric carbon dioxide on terrestrial ecosystems has attracted much attention. For estimating these effects quantitatively| model that expresses the global carbon cycle is needed. We constructed models a express vegetation growth and carbon cycle in soil. In this report| by using these two models| we estimated the carbon cycle between terrestrial ecosystems and the atmosphere and predicted the effects on the global carbon cycle. By this model we can predict that terrestrial ecosystems emit carbon dioxide to the atmosphere with increase of temperature. 2674,1993,2,3,PROJECTED GLOBAL CLIMATE-CHANGE IMPACT ON WATER TEMPERATURES IN 5 NORTH CENTRAL UNITED-STATES STREAMS,The effect of projected global climate change due to a doubling of atmospheric CO2 on water temperatures in five streams in Minnesota was estimated using a deterministic heat transport model. The model calculates heat exchange between the atmosphere and the water and is driven by climate parameters and stream hydrologic parameters. The model is most sensitive to air temperature and solar radiation. The model was calibrated against detailed measurements to account for seasonally variable shading and wind sheltering. Using climate projections from the GISS| GFDL and OSU GCMs as input; stream temperature simulations predict a warming of freely flowing river reaches by 2.4-degrees-C to 4.7-degrees-C when atmospheric CO2 doubles. In small shaded streams water temperatures are predicted to rise by an additional 6-degrees-C in summer if trees along stream banks should be lost due to climate change or other human activities (e.g. logging). These projected water temperature changes have significant consequences for survival and growth of fishes. Simulation with the complete heat budget equations were also used to examine simplified water temperature/air temperature correlations.
3994,1993,2,4,RAIN-FOREST TREES AS A NEW CROP FOR AUSTRALIA,An analysis has been carried out of the prospects of using lesser known rainforest trees as new crops| mainly for high quality cabinetwood production. The economic returns of 43 rainforest trees were assessed using expert opinion and the Delphi method to provide an evaluation and ranking of the most valuable species. Cuban mahogany (Swietenia mahogeni)| American mahogany (Swietenia macrophylla)| West Indian cedar (Cedrela odorata)| teak (Tectona grandis)| and hoop pine (Araucaria cunninghamii) were identified by a simple model as the most valuable tree species. Sensitivity analyses were carried out on the effect of both increased long term timber prices and changes in tree productivity on financial returns. Further research on plantation development and an extensive literature review of the top ten species is also needed. Global warming scenarios indicate that the relative viability of plantations of tropical rainforest species in northern Australia will improve as a result of smaller temperature increases and higher rainfall than in southern Australia. Conditions are now more economically favourable for commercial tree planting than in the past and could lead to the future involvement of financial organizations and the payment of annuities to owners of tree farms. An ultimate aim is the development of markets in tree farms or plantations similar to those in agricultural enterprizes generally. 3975,1993,4,2,RATE COEFFICIENTS FOR REACTIONS OF SEVERAL HYDROFLUOROCARBONS WITH OH AND O((1)D) AND THEIR ATMOSPHERIC LIFETIMES,The rate coefficients for the reaction of OH with CH3F| CHF3| C2H5F| C4H2F8| and C5H2F10 were measured at temperatures between 232 and 378 K using the pulsed laser photolysis-laser-induced fluorescence technique. The rate coefficients for the reaction of O(1D) with the above molecules and CH2F2 were measured at room temperature using time-resolved vacuum-UV atomic resonance fluorescence detection of O(3P). The atmospheric lifetimes needed for the evaluation of global warming potentials were calculated for all six molecules using a one-dimensional atmospheric model using the kinetic data obtained in the present study. 4019,1993,2,4,RECENT WARMING - ICE CORE EVIDENCE FROM TROPICAL ICE CORES WITH EMPHASIS ON CENTRAL-ASIA,Ice cores from the tropics and subtropics| in conjunction with those from the polar regions| provide a multifaceted record (dust| chemistry| stable isotopes| accumulation) of environmental changes which can be viewed both spatially and temporally. This paper emphasizes the oxygen isotopic record (deltaO-18) preserved in cores from the poles to the tropics and assesses the evidence for global warming in the last 50-100 years. From north to south these records include: Camp Century| Greenland| Dunde and Guliya Ice Caps| China| Gregoriev Ice Cap| Kirghizia (formerly part of USSR)| Quelccaya Ice Cap| Peru and Siple Station and South Pole| Antarctica. The central Asian records along with that from Quelccaya provide strong evidence of recent and rapid warming in the tropics and subtropics| For the Dunde Ice Cap| where a long paleoclimatic record is available| the warming in this century appears to be unprecedented in the Holocene. These tropical and subtropical records contrast sharply with those from polar cores which show little evidence of a recent warming. These data suggest that either the recent warming is a middle and lower latitude phenomenon or that these high altitude tropical and subtropical glaciers may be more sensitive to climate changes than the massive polar ice sheets. Regardless| the current rapid disintegration of many tropical and subtropical glaciers may result in the permanent loss of numerous unique archives. 3986,1993,3,3,REDUCING ATMOSPHERIC CO2 USING BIOMASS ENERGY AND PHOTOBIOLOGY,Biological systems are among the most promising| environmentally sustainable alternatives for reducing atmospheric CO2 levels. Biomass can act as a reservoir of carbon| or as a direct substitute for fossil fuels with no net contribution to atmospheric CO2 if produced and used sustainably. We examine the role of biomass in mitigating global warming and contributing to the development of future energy strategies. we conclude that the use of biomass for fossil fuel substitution would be far more effective| in reducing atmospheric CO2 than to simply sequester CO2 in forests in most circumstances. Furthermore| since bioenergy could be less costly -than coal and petroleum| this strategy has an economic advantage over many of the carbon mitigation options. Photobiology and photochemistry are possible future routes for CO2 reduction. The use of microalgae in photobioreactors is feasible for CO2 removal as has been demonstrated in a number of laboratories. Energy balances with such systems need to be optimised since parameters such as light (actual and artificial) and waste heat play crucial roles. 2700,1993,4,4,RESPONSE OF THE TERRESTRIAL BIOSPHERE TO GLOBAL CLIMATE CHANGE AND HUMAN PERTURBATION,Despite 20 years of intensive effort to understand the global carbon cycle| the budget for carbon dioxide in the atmosphere is unbalanced. To explain why atmospheric CO2 is not increasing as rapidly as it should be| various workers have suggested that land vegetation acts as a sink for carbon dioxide. Here| I examine various possibilities and find that the evidence for a sink of sufficient magnitude on land is poor. Moreover| it is unlikely that the land vegetation will act as a sink in the postulated warmer global climates of the future. In response to rapid human population growth| destruction of natural ecosystems in the tropics remains a large net source of CO2 for the atmosphere| which is only partially compensated by the potential for carbon storage in temperate and boreal regions. Direct and inadvertent human effects on land vegetation might increase the magnitude of regional CO2 storage on land| but they are unlikely to play a significant role in moderating the potential rate of greenhouse warming in the future.
4078,1993,3,3,RESPONSE OF THE THERMAL STRUCTURE OF LAKE-ONTARIO TO DEEP COOLING WATER WITHDRAWALS AND TO GLOBAL WARMING,It has been proposed to cool buildings in downtown Toronto using cold| deep water withdrawn from Lake Ontario. 50 m3 s-1 of sub-thermocline water would be withdrawn from a depth of 80 m at a temperature close to 4-degrees-C| distributed to chillers throughout the city| and discharged on the surface in the nearshore zone at a temperature of 12-degrees-C Compared with electrically-powered chillers| the Deep Lake Water Cooling (DLWC) scheme is thermodynamically elegant and environmentally beneficial in many ways. Using a one-dimensional thermodynamic model of Lake Ontario| this paper assesses the physical impact of the DLWC scheme on the whole lake under present and future conditions. We conclude that the lake could presently absorb the heat from the proposed Toronto installation and 20 others like it without major lake-wide physical changes. At a conservative estimate of 1000 m3 s-1 with an 8-degrees-C temperature differential| the DLWC scheme would reject approximately 33.5 GW of ''waste heat'' to Lake Ontario. Under our best estimate of a 2 x CO2 climate scenario| the deep waters could be 2-3-degrees-C warmer than they are now. The DLWC system would be less efficient| but the lake would retain a similar overall cooling capacity. Neither biological consequences nor the local physical impact of the discharge of heated subsurface water from the DLWC system are addressed in this study. 2680,1993,4,3,SATELLITE OBSERVATION OF LAKE ICE AS A CLIMATE INDICATOR - INITIAL RESULTS FROM STATEWIDE MONITORING IN WISCONSIN,The research reported herein focused on the general hypothesis that satellite remote sensing of large-area| long-term trends in lake ice phenology (formation and breakup) is a robust| integrated measure of regional and global climate change. To validate this hypothesis| we explored the use of data from the Advanced Very High Resolution Radiometer (AVHRR) to discriminate the presence and extent of lake ice during the winter of 1990-1991 on the 45 lakes and reservoirs in Wisconsin with a surface area greater than 1|000 hectares. Our results suggest both the feasibility of using the AVHRR to determine the date of lake ice breakup as well as the strong correlation (R = -0.87) of the date so derived with local surface-based temperature measurements. These results suggest the potential of using current and archival satellite data to monitor changes in the date of lake ice breakup as a means of detecting regional ''signals'' of greenhouse warming.
4030,1993,2,3,SEA-LEVEL RISE - DESTRUCTION OF THREATENED AND ENDANGERED SPECIES HABITAT IN SOUTH-CAROLINA,Concern for the environment has increased over the past century| and the US Congress has responded to this concern by passing legislation designed to protect the nation's ecological biodiversity. This legislation| culminating with the Endangered Species Act of 1973| has been instrumental in defining methods for identifying and protecting endangered or threatened species and their habitats. Current legislation| however| assumes that the range of a protected species will stay constant over time. This assumption may no longer be valid| as the unprecedented increase in the number and concentration of greenhouse gases in the atmosphere has the potential to cause a global warming of 1.0-4.5-degrees-C and a sea-level rise (SLR) of 31-150 cm by the year 2100. Changes in climate of this magnitude are capable of causing shifts in the population structure and range of most animal species. This article examines the effects that SLR may have on the habitats of endangered and threatened species at three scales. At the regional scale 52 endangered or threatened plant and animal species were found to reside within 3 m of mean sea level in the coastal stages of the US Southeast. At the state level| the habitats of nine endangered or threatened animals that may be at risk from future SLR were identified. At the local level| a microscale analysis was conducted in the Cape Romain National Wildlife Refuge| South Carolina| USA| on the adverse effects that SLR may have on the habitats of the American alligator| brown pelican| loggerhead sea turtle| and wood stork. 4013,1993,4,4,SENSITIVITY OF TROPICAL CYCLONE INTENSITY TO SEA-SURFACE TEMPERATURE,Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one of the potential consequences of global warming. This scenario is based almost entirely on the general circulation model predictions of warmer sea surface temperature (SST) with increasing levels of atmospheric CO2 and some theories of tropical cyclone intensification that support the notion of more intense systems with warmer SST. Whether storms are able to achieve this theoretically determined more intense state depends on whether the temperature of the underlying water is the dominant factor in tropical cyclone intensification. An examination of the historical data record in a number of ocean basins is used to identify the relative importance of SST in the tropical cyclone intensification process. The results reveal that SST alone is an inadequate predictor of tropical cyclone intensity. Other factors known to affect tropical cyclone frequency and intensity are discussed. 3950,1993,4,4,SIMPLIFIED DYNAMIC-MODEL ON CARBON EXCHANGE BETWEEN ATMOSPHERE AND TERRESTRIAL ECOSYSTEMS,Global warming is one of the serious global environmental problems and its major reason is considered cd to be the increase of atmospheric CO2 concentration. In order that more precise and rational predictions of global warming and other climatic phenomena become possible by numerical simulations| the establishment of global material cycle models is essential particularly for carbon. As the first step in constructing this carbon cycle model| a simplified dynamic model describing the carbon exchange between the atmosphere and terrestrial ecosystems was developed. The carbon storage in biomass and the net primary production of various vegetations in steady states and their transitional changes in non-steady states derived by the model calculation were in good agreement with those previously reported in the literature. The net ecosystem production was also estimated for five types of vegetations during a long growth period. Though further improvements of the model are still needed| we can conclude at this stage that the basic framework of the carbon cycle model on the terrestrial ecosystems which may play a role as one of the sub-models of a global carbon cycle model was established. 3956,1993,4,6,SIMULATING PAST AND FORECASTING FUTURE CLIMATES,Climatic change is not a new phenomenon| nor is it random| as most of the variation can be explained in terms of variations in the sunlight reaching the surface of the Earth. The solar energy reaching the surface is modified by the aerosols in the atmosphere| however| and that means primarily aerosols of volcanic origin. The climatic history of the Earth is divided up into episodes with abrupt beginnings and ends. Rapid changes from one climatic state to another are normal. The fluctuations within|this century do not appear to be unusual in any respect. To the Author's knowledge there is no evidence that past climatic changes| including those of the last decades| are related to changes in carbon dioxide in the atmosphere - except perhaps for warmer nights in the North American mid-west. It is not possible to simulate past climates using carbon dioxide content as the main variable| but it is possible to do so using calculated solar radiation as modified by volcanic aerosols. This strongly suggests that forecasts of the climatic future based on carbon dioxide increases are suspect. Computerized models of the climate that can simulate decadal and century-long variations of climate as well as variations on the millennium scale| suggest that the climate will not warm dramatically in the next fifty years| but will| rather soon after that| begin a rather rapid change towards the next glacial climate. Changes in our global array of cultures| sufficient to affect the global climate in a way which we perceive as beneficial| probably are not possible within centuries without massive physical conflict. There are both winners and losers when the climate changes in a non-uniform pattern| as it always does. It is a well-known fact that a global change of 0.5-degrees-C in mean temperature| such as has happened in recent years| might produce some regions of 10-degrees-C change in either direction and some regions with no change at all| and additionally an array of rainfall changes of various magnitudes. Russians would welcome warming of their climate! The problems with attempting to modify the global climate in a particular direction are enormous and would be incredibly costly. This is compounded by our not knowing what the climate would. do without intervention. Only one thing is truly clear| and ii is that the present knowledge of the climatic effect of changing carbon dioxide content of the atmosphere is totally inadequate as a basis for initiating any global attempt to change the climate. The indicated action would appear to be to engage in some high-quality climatic research based on sound science before taking global risks greater than those that might arise from the putative 'global warming'. 4058,1993,4,4,SOIL WARMING AND TRACE GAS FLUXES - EXPERIMENTAL-DESIGN AND PRELIMINARY FLUX RESULTS,We conducted several experiments to determine a procedure for uniformly warming soil 5-degrees-C above ambient using a buried heating cable. These experiments produced a successful design that could: 1) maintain a temperature difference of 5-degrees-C over a wide range of environmental conditions; 2) reduce inter-cable temperature variability to ca. 1.5-degrees-C; 3) maintain a temperature difference of 5-degrees-C near the edges of the plot; and 4) respond rapidly to changes in the environment. In addition| this design required electrical power only 42% of the time. Preliminary measurements indicate that heating increased CO2 emission by a factor of ca. 1.6 and decreased the C concentration in the O soil horizon by as much as 36%. In addition| warming the soil accelerated the emergence and early growth of the wild lily of the valley (Maianthemum canadense Desf.). The relationship between CO2 flux and soil temperature derived from our soil warming experiment was consistent with data from other hardwood forests around the world. Since the other hardwood forests were warmed naturally| it appears that for soil respiration| warming the soil with buried heating cables differs little from natural| aboveground warming. By warming soil beyond the range of natural variability| a multi-site| long-term soil warming experiment may be valuable in helping us understand how ecosystems will respond to global warming. 4028,1993,3,3,SOLAR-HYDROGEN FUEL-CELL VEHICLES,Hydrogen is an especially attractive transportation fuel. It is the least polluting fuel available| and can be produced anywhere there is water and a clean source of electricity. A fuel cycle in which hydrogen is produced by solar-electrolysis of water| or by gasification of renewably grown biomass| and then used in a fuel-cell powered electric-motor vehicle (FCEV)| would produce little or no local| regional or global pollution. Hydrogen FCEVs would combine the best features of battery-powered electric vehicles (BPEVS)-zero emissions| high efficiency| quiet operation and long life-with the long range and fast refueling time of internal-combustion-engine vehicles (ICEVs). If fuel-cell technology develops as hoped| then hydrogen FCEVs will be a significant advance over both hydrogen ICEVs and solar BPEVs: they will be cleaner and more efficient than hydrogen ICEVs| have a much shorter refueling time than BPEVs and have a lower life-cycle cost than both. Solar-hydrogen fuel-cell vehicles would be general-purpose zero-emission vehicles| and could be an important component of a strategy for reducing dependence on imported oil| mitigating global warming and improving urban air quality| at an acceptable cost. 3972,1993,2,4,SPATIAL AND TEMPORAL ANALYSIS OF MIDDLE-EASTERN TEMPERATURE-CHANGES,The intense interest in the greenhouse effect has stimulated detailed studies of temperature records in North America| Europe| and Australia. In this investigation| the temperature records from the Middle East region (defined here as the land area extending from Morocco to Afghanistan) are investigated over the period 1950-1990. Results reveal a linear| statistically significant| temperature increase of 0.07 degrees C per decade over the study area that may or may not be associated with the concurrent rise in equivalent carbon dioxide from approximately 350 ppm to 430 ppm. Seasonal analyses reveal that most of this increase has occurred in the spring season| moderate amounts of warming occurred in the summer and fall seasons| and virtually no warming has occurred in the winter months. An analysis of spatial controls on these temperature changes reveals a general cooling effect associated with the atmospheric sulfate levels and a warming effect associated with the degree of human-induced desertification. The results of this study may prove useful to policymakers in the Middle East who are confronted with many difficult decisions regarding highly interrelated global warming and energy issues. 3976,1993,3,4,STABILIZING UNITED-STATES NET CARBON EMISSIONS BY PLANTING TREES,This study investigates bow much the costs of stabilizing net carbon emissions in the United States at 1990 levels between 1990 and 2030 can be reduced by using trees to sequester carbon. Using the Fossil2 energy/economic model maintained by the U.S. Department of Energy| we estimate that trees can reduce the overall costs of stabilizing net carbon emissions by as much as 80 percent. More work is needed to verify the magnitude of the cost reduction. 3952,1993,2,4,STATISTICAL DEPENDENCE OF ALBEDO AND CLOUD COVER ON SEA-SURFACE TEMPERATURE FOR 2 TROPICAL MARINE STRATOCUMULUS REGIONS,The relationship between sea surface temperature (SST) and albedo or cloud cover is examined for two tropical regions with high values of cloud radiative forcing and persistent marine stratocumulus (mSc)-one off the west coast of Peru| the other off the west coast of Angola. The data span five years| from December 1984 to November 1989. Albedos are from the Earth Radiation Budget Experiment| cloud covers are from the International Satellite Cloud Climatology Project| and SSTs are from the Climate Analysis Center. Negative correlation coefficients between albedo and SST are found to be about -0.8 when the seasonal variation of the entire dataset is analyzed. The interannual variation and the spatial variation of individual months also yields correlation coefficients that are negative. The correlation between cloud cover and SST is found to be similar to but weaker than the correlation between albedo and SST| suggesting a decrease in cloud amount and a decrease in cloud albedo with increasing SST for these regions. The corresponding albedo sensitivity averages -0.018 K-1 with local values reaching -0.04 K-1. These findings are valid from 19 degrees C to 25 degrees C for the Peru mSc and 22 degrees C to 27 degrees C for the Angola mSc. These temperatures approximately bound the domains over which mSc is the prevalent cloud type within each region. These results imply a potential positive feedback to global warming by marine stratocumulus that ranges from similar to 0.14 W m(-2) K-1 to similar to 1 W m(-2) K-1| depending on whether or not our results apply to all marine stratocumulus. While these values are uncertain to at least +/-50%| the sensitivity of albedo to sea surface temperature in the present climate may serve as a useful diagnostic tool in monitoring the performance of global climate models. 2668,1993,3,2,STORAGE AND UTILIZATION OF CO2 IN PETROLEUM RESERVOIRS - A SIMULATION STUDY,There is a growing concern about the effect of greenhouse gases on global temperatures and its consequences. Among many greenhouse gases| carbon dioxide produced as a result of fossil fuel burning is a major contributor due to the huge volume emitted into the atmosphere. Because fossil fuels remain the driving force of modem economies| any economic growth in the developed or developing countries results in an increased emission of carbon dioxide. Consequently| reduction of carbon dioxide emissions has become an important issue. The Intergovernmental Panel on Climate Change (IPCC) estimates that a worldwide reduction of the emission of green house gases by more that 60% is necessary to avert' the global climate change. It is now well recognized that the disposal issue is the most important obstacle to overcome for a practical solution of the carbon dioxide problem. In this paper a simulation study on the storage and utilization of carbon dioxide in petroleum reservoirs has been carried out. For simple storage| simulation studies to determine the capacity of a given reservoir are conducted for different reservoirs with a wide range of governing parameters. Major parameters studied are: initial reservoir pressure| final average reservoir pressure| impurities in the injected gas| petrophysical properties of the reservoir| and initial fluid saturations. For the utilization| simulation studies are carried out for both miscible and immiscible flooding enhanced oil recovery (EOR) processes. It is difficult to maintain carbon dioxide miscibility in a reservoir. It is found that immiscible but stable injection of carbon dioxide may be very effective in recovering oil.
4053,1993,3,3,STRUCTURAL COMPARISON OF THE MODELS IN EMF-12,This paper analyses the structures of the energy and economic models represented in the recently completed Energy Modeling Forum (EMF) study| EMF 12: Economic Impacts of Policies to Reduce Energy-Sector Carbon Dioxide Emissions. The 14 models in the study are heterogeneous| which has a number of advantages. Chief among these is the greater number of insights obtainable by comparing the models' results in and across' global warming policy scenarios. To fully appreciate the results| however| it is necessary to understand how a model's structure affects its output. The disadvantage of a diverse set of models is that it complicates structure comparison| and thereby the interpretation of results. The relevant model characteristics fall into three broad areas of comparison. The first is the model type| including market representation. Despite the many differences among the models| five distinct classes of market representations are seen within which models have great similarity. This simplifies understanding the remaining areas of comparison: energy demand and supply modelling. The foci here are the representation of capital stock dynamics and market penetration of carbon free energy sources respectively. 4092,1993,3,4,TECHNICAL OPTIONS FOR ENERGY-CONSERVATION AND CONTROLLING ENVIRONMENTAL-IMPACT IN HIGHWAY VEHICLES,Manufacturers of light-duty highway vehicles are sometimes caught between the desire of the consumer for a reasonable-cost conveyance that is a pleasure to operate and the mandates of regulation seeking societal objectives of energy conservation and preservation of air quality. The prospects for improving conventional vehicles in these areas by the year 2000 are considered. Alternative engines and fuels are reviewed for the same time-frame. The status of the battery-electric vehicle is assessed. Shifting attention to the mid-21st century| the possibility of global warming is chanelling thought toward non-fossil fuels| with hydrogen being added to the list of options. 2669,1993,3,2,TECHNOLOGICAL CONSIDERATIONS FOR PLANNING THE GLOBAL CARBON FUTURE,The atmospheric level of carbon dioxide (CO2) is the dominant variable in the anthropogenic influence of future global climate change. Thus| it is critical to understand the long-term factors affecting its level| especially the longer-range technological considerations. Most recent analyses of the problem focus on the next 20 to 100 years. While great uncertainties exist in longer-term projections of CO2| it is of concern that the longer-range buildup (over many centuries) may be of substantial magnitude and might be so despite major efforts to reduce use of fossil reserves for energy| save world forests| and/or collect and dispose of CO2. This paper summarizes some of the recent literature relating to the longer-term CO2 problem and discusses some of the technological considerations for known prevention and mitigation approaches in the context of this longer-term problem. These approaches include: renewables (solar photovoltaics| wind| and biomass)| conservation| flue-gas and fuel CO2 sequestration via disposal on land or in the ocean| carbon recycling (chemical/biological utilization)| and atmospheric CO2 fixation/utilization via terrestrial and marine approaches. These are discussed along with other strategies to identify those that 1) could be major factors in preventing long-term CO2 buildup| 2) would be environmentally sound but likely to have more limited long-range CO2 impact| 3) would be environmentally uncertain or uncertain for other reasons| and 4) would be environmentally questionable or unlikely solutions for other reasons.
3973,1993,2,4,TEMPORAL VARIATION IN GROWTH-RATE AND AGE AT MATURITY OF MALE PAINTED TURTLES| CHRYSEMYS-PICTA,Growth rates of juveniles and age at maturity of males were examined in a population of painted turtles| Chrysemys picta| inhabiting a marsh in southwestern Michigan (approximately 42 degrees 24'N| 85 degrees 24'W) to compare temporal variation in these two important life history traits within a decade. Elongation of the third right foreclaw was used as an indicator of incipient sexual maturity of males. Males in the late 1980s reached maturity at least a year earlier than did those in the early 1980s. Analysis of climatological data revealed that growing seasons in the late 1980s were typically warmer and longer than in the early years of the decade. The observed changes in juvenile growth rates and age at maturity of male C. picta are in accord with recent field and laboratory studies of emydid turtles. They also support predictions of life history theory| and may serve as working hypotheses that can be tested with data from other long-term projects. If substantiated| these patterns may indicate how some freshwater turtle populations in temperate latitudes might respond to predicted global warming trends. 3977,1993,3,2,THE CARBON AND ENERGY BUDGETS OF ENERGY CROPS,Global warming is said to be caused by the build up of active greenhouse gases in our atmosphere and carbon dioxide - released on the combustion of fossil fuels is thought to be the most important of these. Agricultural crops| grown specifically for use as a fuel source| might play an important role in reducing our consumption of fossil fuel sources through substitution. However| in order to fully qualify as a ''beneficial crop'' it must be clearly shown that production entails a net benefit in terms of energy output to energy input i.e.; it has a positive energy balance. This paper considers the difficulties in assessing both carbon and energy budgeting. It describes a recently developed computer model which attempts to define the energy and carbon inputs and outputs of the leading UK energy crop| that is of short rotation coppice (SRC). Preliminary results show that SRC| when displacing fossil fuel| has a very positive energy yield with the added benefit of carbon saving in terms of offset emissions. The computer model takes account of direct and indirect energy and carbon inputs to the crop| allowing the model user to determine the sensitivity of individual cropping operations including establishment| fencing| harvesting operations| rotation and cutting cycle variations| the impact of field size| transport distance from the farm to the point of utilisation| the energy cost of storage and drying. Each management decision influences the final energy or carbon ratio of the SRC crop. Such complexity makes a definitive statement on the energy/carbon ratio for crop production difficult| however if a standard management system is adopted (as described later) the energy ratio of growing SRC for fuel may be assigned. In the case examined here a ratio of 30 : 1 (energy units produced : used) is reported. However| this ratio is sensitive to variation in crop yield and management efficiency and so| although the ratio is positive| this should not encourage a wasteful attitude to crop management systems. In terms of carbon balances| the most important consideration is the substitution value of the material in relation to fossil fuels. In this paper| figures presented refer to wood substituted for coal use and pertain to a field area of 1 hectare (ha). If field size is increased up to 3ha| then the energy and carbon ratios improve by approximately 15%. 3969,1993,4,4,THE CARBON-CYCLE AND GLOBAL FOREST ECOSYSTEM,Attempts to account for the fluxes by quantifying C sources and sinks have provided evidence of a missing C sink (Detwiler and Hall| 1988)| which may be located somewhere in the temperate region of the northern hemisphere (Tans et al.| 1990). Until recently| most estimates have concluded that the temperate forest is a small C source. Two recent papers (Sedjo| 1992; Kauppi et al.| 1992) provided evidence that the temperate forests are substantial C sinks. This paper combines these earlier findings on temperate forest carbon sequestration with a new estimate of the annual C releases due to tropical deforestation| 1.7 Gt| which is obtained using the FAO estimates of the rate of deforestation in the tropics over the decade of the 1980s and conservative estimates of C releases associated with this deforestation. Finally| to this is added the crude estimate of C export by the global river system found in Hall et al. (1992). Applying these estimates of the C sink function of both temperate and tropical forests to Detwiler and Hall's alternative C budgets largely eliminates the ''missing C'' hypothesized by Detwiler and Hall| and Tans et al. 2699,1993,4,4,THE CURRENT STATUS OF OPERATIONAL SATELLITE PRODUCTS FOR CLIMATE STUDIES,The current status of climate products being obtained from the real-time processing of operational satellite observations at NOAA is reviewed. Current global operational products relevant to climate studies include: atmospheric temperature and water vapor profiles| winds| clouds| aerosols| ozone| sea surface temperature| vegetation index| snow cover and sea ice| planetary albedo| and outgoing longwave radiation. Current experimental operational products include sea surface wind speed| precipitable water| precipitation rate| snow cover and sea ice cover from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager and surface and atmospheric longwave radiation fluxes from the TIROS Operational (SSM/I)| and surface and atmospheric longwave radiation fluxes from the TIROS Operational Vertical Sounder (TOVS) radiance observations. Recent results| accuracy estimates based on comparison with ground truth| and problems and possibilities for using operational satellite data for long-term global climate change studies are presented.
2691,1993,3,4,THE DILEMMA OF FOSSIL-FUEL USE AND GLOBAL CLIMATE CHANGE,Fossil fuels present the difficult-to-reconcile dilemma that the energy systems of today's society dictate that we use great quantities of fossil fuels to produce the energy we need| but their use results in the liberation of large volumes of carbon dioxide (CO2)| which is one of the so-called ''greenhouse gases''. Certain models predict that uncontrolled releases of greenhouse gases could result in unacceptable increases in global mean temperature. This dilemma is examined and a method of management of the use of fossil fuels is presented that will help to mitigate the problems their use creates. The challenge is to avoid the dilemma by technology and policy intervention so that fossil fuels are used to the net benefit of society and its environment. We should take those low-cost measures that slow greenhouse gas emissions| and we should be prepared technologically to accomplish much larger reductions if necessary. At present| our technological insurance is not in place| but the opportunities for improvement are great| even for fossil fuels. Several low-cost actions that can be taken in the near term include the establishment of policies including R&D that encourage the development of more efficient and economical end-use and conversion technologies (e.g.| more efficient gas turbines| fuel cells| oxygen-blown gasifiers| and processes for producing hydrogen from fossil sources); more intensive R&D to accelerate the development of better nonfossil sources including direct solar| biomass| and other renewables| fission| and fusion; policies that encourage the substitution of hydrogen-rich for hydrogen-lean fuels and expansion of the natural gas system| particularly in developing nations; cooperation by western industrialized countries in providing technical assistance to developing and Eastern European countries for producing energy technologies that are both economically and environmentally more attractive| including expanding the development and use of the natural gas resources of the former Soviet Union; R&D to increase our understanding of the global cycle of CO2 releases to the atmosphere and its removal by the oceans and by terrestrial ecosystems so that climate stabilization targets and policies can be better established; and experiments with CO2 recovery and sequestration techniques so that the economic and environmental impacts are better understood.
2697,1993,2,4,THE EFFECT OF SOIL-MOISTURE AND THAW DEPTH ON CH4 FLUX FROM WET COASTAL TUNDRA ECOSYSTEMS ON THE NORTH SLOPE OF ALASKA,Results from a 2-year study of wet coastal tundra ecosystems located near Prudhoe Bay| Alaska indicate that CH4 flux to the atmosphere is strongly controlled by soil moisture content and the depth of the seasonally thawed soil active layer. Daily CH4 flux from a flooded and well drained site on the Prudhoe Bay oil fields was on average 0.7 and 0.1 gC m-2 day-1| respectively over both sampling seasons. Daily CH4 flux in an area located approximately 50 km south of Prudhoe Bay was considerably higher. This area (APL 133-3) contained a flooded| moist| and dry site which emitted on average 1. 5| 1. 1| and 0.2 gC m-2 day-1 to the atmosphere| respectively over both sampling seasons. These flux rates represent significant inputs of CH4 to the atmosphere. Evidence of the importance of soil moisture and thaw depth in controlling CH4 flux| coupled with the predominantly waterlogged| anaerobic conditions of wet tundra soils| suggest the potential for strong interactions of this soil-atmosphere system with global climate change.
4041,1993,4,6,THE GLOBAL TEMPERATURE DATA,When all of the greenhouse gases are expressed in CO2 equivalents| we find that over the past 100 years| equivalent CO2 values have increased by 40%. Over this period| the temperature of the planet appears to have increased by 0.5-degrees-C| however| much of this warming may be explained by a variety of non-greenhouse factors. In addition| fully 75% of the global warming of the past century occurred before the end of the Second World War| long before most of the trace gases were added to the atmosphere. Furthermore| the celebrated warming of the 1980s and early 1990s is seriously challenged by recent satellite-based global temperature measurements that show essentially no warming at all. In an effort to explain these findings| climate scientists are pointing to the cooling effects of human-induced increases in atmospheric SO2. The bottom line is simple-despite a public perspective to the contrary| the global temperature record provides little support for the catastrophic view of the greenhouse effect.
2692,1993,2,3,THE IMPACTS OF CLIMATE CHANGE ON RICE YIELD - A COMPARISON OF 4 MODEL PERFORMANCES,Increasing concentrations of carbon dioxide (CO2) and other greenhouse gases are expected to modify the climate of the earth in the next 50-100 years. Mechanisms of plant response to these changes need to be incorporated in models that predict crop yield estimates to obtain an understanding of the potential consequences of such changes. This is particularly important in Asia where demographic forecasts indicate that rice supplies worldwide will need to increase by 1.6% annually to the year 2000 to match population growth estimates. The objectives of this paper are (1) to review the major hypotheses and/or experimental results regarding rice sensitivity to climate change and (2) to evaluate the suitability of existing rice models for assessing the impact of global climate change on rice production. A review of four physiologically-based rice models (RICEMOD| CERES-Rice| MACROS| RICESYS) illustrates their potential to predict rice responses to elevated CO2 and increased temperature. RICEMOD does not respond to increases in CO2 nor to large increases in temperature. Both MACROS and CERES (wetland rice) responses to temperature and CO2 agree with recent experimental data. RICESYS is an ecosystem model which predicts herbivory and inter-species competition between rice and weeds but does not respond to CO2. Its response to increasing temperature also agrees with experimental data.
3995,1993,2,4,THE LOWLAND-TO-UPLAND TRANSITION MODELING PLANT-RESPONSES TO ENVIRONMENTAL-CHANGE,A published correlative model has predicted that the distributional limits of plants and vegetation zones on mountains will increase in altitude with global warming. I test this hypothesis using results from published experimental studies. Investigations and models of the responses of leaf growth to temperature are in accord with the prediction. However| the individualistic responses of species to CO2 enrichment indicate that the prediction is unlikely to be true for all species: growth is stimulated by CO2 enrichment for some species but not for others. Wind speed generally increases with altitude on mountains| and plants from high altitude tend to be more wind resistant than species from the lowland. Therefore it is expected that| particularly on wind-swept mountains| global warming will not necessarily be followed by the spread of lowland species into the uplands. 4069,1993,3,3,THE NET GREENHOUSE WARMING FORCING OF METHANOL PRODUCED FROM BIOMASS,Recent national and international actions regarding atmosphere warming mitigation| clean technology| and technology transfer have emphasized the need for a method for unambiguous greenhouse gas emissions analysis for comparing technologies| documentation of application of the method| and proof of applicability. We have developed and applied such an approach to production of methanol fuel from woody biomass. The entire approach is detailed| whereby the system was defined| its emissions for its entire lifetime delineated| and the atmospheric warming forcing calculated for that lifetime plus after effects. The results are presented with material and energy balances including ancillary equipment| external energy subsidies and invested quantities. These extend the analysis considerably beyond those possible using the global warming potential (GWP). For wood input of 283 mg day-1| 70 mg of methanol are produced. System carbon dioxide emissions are 3.18 tonne/tonne methanol produced| with another 1.37 mg emitted when that tonne methanol is burned in a vehicle. System energy usage efficiency was 41.2%| and 41.1% with inclusion of energy to construct the system. In essence| more than two Joules of carbon must be produced in wood for every Joule burned in the vehicle. 3982,1993,2,2,THE PLANKTON MULTIPLIER - POSITIVE FEEDBACK IN THE GREENHOUSE,The plankton multiplier is a positive feedback mechanism linking the greenhouse effect and biological pump (Woods|J.D.| Royal Commission on Environmental Pollution| 1990). As pollution increases the atmospheric concentration of carbon dioxide| the enhanced greenhouse effect induces radiative forcing of the ocean| which diminishes the depth of winter convection| reducing the annual resupply of nutrients to the euphotic zone and therefore the annual primary production. That weakens the biological pump| which contributes to oceanic uptake of CO2. As the ocean takes up less CO2| more remains in the atmosphere| accelerating the rise in radiative forcing. We have used a mathematical model of the upper ocean ecosystem| based on the Lagrangian Ensemble method| to estimate the sensitivity of the biological pump to radiative forcing| which lies at the heart of the plankton multiplier. We conclude that increasing radiative forcing by 5 W m-2 (equivalent to doubling atmospheric CO2) reduces the deep flux of particulate carbon by 10%. That sensitivity is sufficient to produce significant positive feedback in the greenhouse. It means that the plankton multiplier will increase the rate of climate change in the 21st century. It also suggests that the plankton multiplier is the mechanism linking the Milankovich effect to the enhanced greenhouse effect that produces global warming at the end of ice ages. 4074,1993,4,4,THE POTENTIAL EFFECTS OF CLIMATE CHANGE ON SUMMER SEASON DAIRY-CATTLE MILK-PRODUCTION AND REPRODUCTION,The potential direct effects of possible global warming on summer season dairy production and reproduction were evaluated for the United States and Europe. Algorithms used for milk production and conception rate were previously developed and validated. Three widely known global circulation models (GISS| GFDL| and UKMO) were used to represent possible scenarios of future climate. Milk production and conception rate declines were highest under the UKMO model scenario and lowest under the GISS model scenario. Predicted declines for the GCM scenarios are generally higher than either '1 year in 10' probability-based declines or declines based on the abnormally hot summer of 1980 in the United States. The greatest declines (about 10% for the GISS and GFDL scenarios| and about 20% for the UKMO scenario) in the United States are predicted to occur in the Southeast and the Southwest. Substantial declines (up to 35%) in conception rates were also predicted in many locations| particularly the eastern and southern United States. These areas correspond to areas of high dairy cattle concentration. They already have relatively large summer season milk production declines resulting from normally hot conditions. Thus| the actual impacts of increased production declines may be greater in other areas| which are not accustomed to large summer season declines and therefore may require more extensive mitigation measures. 2663,1993,2,3,THE POTENTIAL RESPONSE OF GLOBAL TERRESTRIAL CARBON STORAGE TO A CLIMATE-CHANGE,An analysis is undertaken to examine the potential impacts of a global climate change on patterns of potential terrestrial C storage and resulting fluxes between terrestrial and atmospheric pools. A bioclimatic model relating the current distribution of vegetation to global climate patterns is used to examine the potential impacts of a global climate change on the global distribution of vegetation. Climate change scenarios are based on the predictions of two general circulation model equilibrium simulations for a 2XCO2 atmosphere. Current estimates of C reserves in the vegetation types and associated soils are then used to calculate changes in potential terrestrial C storage under the two climate change scenarios. Results suggest a potential negative feedback to increasing atmospheric concentrations of CO2| with the potential for terrestrial C storage increasing under both scenarios. These results represent an equilibrium analysis| assuming the vegetation and soils have tracked the spatial changes in climate patterns. An approach for providing an estimate of the transient response between the two equilibria (i.e.| current and 2XCO2 climates) is presented. The spatial transitions in vegetation predicted by the equilibrium analyses are classified as to the processes controlling the transition (eg.| succession| dieback| species immigration). Estimates of the transfer rates related to these processes are then used to estimate the temporal dynamics of the vegetation/soils change and the associated C pools. Results suggest that although the equilibrium analyses show an increased potential for C storage under the climate change| in the transient case the terrestrial surface acts as a source of CO2 over the first 50 to 100 yrs following climate change.
3953,1993,2,3,THE RELATIONSHIP BETWEEN GLOBAL WARMING AND METHANE GAS HYDRATES IN THE EARTH,Temperature rise due to the increased concentration of trace atmospheric gases (TAG) in the atmosphere has the potential to cause decomposition of the methane hydrates in many parts of the earth. Methane gas hydrate reservoirs are located within permafrost or sediment underlying permafrost or below the ocean floor. The possibility of methane hydrate decomposition due to global warming is investigated by using a mathematical model based on heat conduction in single and composite media. Phase change within permafrost is taken into account. The temperature profiles and the critical time required for the onset of methane hydrate decomposition were computed and found to depend on the global warming scenario| the thermophysical properties of the earth and the required driving force for hydrate decomposition. The temperature at the top of a typical methane hydrate zone will begin to rise within the next 100 yr under a global temperature rise of 0.08-degrees-C/yr. However| methane hydrate decomposition will require a finite driving force and thus will occur later. Under a global temperature rise of 0.006-degrees-C/yr| these phenomena will be substantially delayed. 4036,1993,5,4,THE SIGNIFICANCE OF MARGINOPORA-VERTEBRALIS (FORAMINIFERA) IN SURFICIAL SEDIMENTS AT ESPERANCE| WESTERN-AUSTRALIA| AND IN LAST INTERGLACIAL SEDIMENTS IN NORTHERN SPENCER GULF| SOUTH AUSTRALIA,Surficial sediments at Esperance| on the southern coast of Western Australia| are predominantly bioclastic carbonates in which tests of foraminifera are a major constituent. The megascopic species Marginopora vertebralis is prolific| occupying relatively protected areas of algal turf and seagrasses. The abundance of this normally tropical foraminifer at southern latitudes can be attributed to the Leeuwin Current| which brings warm waters from the tropics to southwestern Australia| and then eastwards| past Esperance into the Great Australian Bight. The Leeuwin Current is significantly warmer than the cool interfacing waters of the Southern Ocean that otherwise characterise the southern Australian continental shelf. Last interglacial sediments of the Glanville Formation| in northern Spencer Gulf of South Australia| host an assemblage of fossil foraminifera which is similar to that of the modern environment at Esperance| especially the presence of M. vertebralis. Two bivalve molluscs| Anadara trapezia and Pinctada carchariarium| both characteristic of warm waters| are also present in the Glanville Formation. Marginopora vertebralis and other faunal elements migrated to South Australia by means of the last interglacial equivalent of the Leeuwin Current| which apparently had greater definition at that time. It may therefore be inferred that| during other times of global warming and corresponding higher sea levels| the palaeo-Leeuwin current had greater ecological influence across the continental shelf of Southern Australia. Thus| warm-water marine fossils in the Glanville Formation do not necessarily signify last interglacial water temperatures for the open Southern Ocean| beyond the continental shelf. Similarly| it cannot be assumed that these fossils necessarily indicate a last interglacial climate for terrestrial southern Australian that was warmer than presently prevails. 4003,1993,3,3,THE TECHNICAL CHALLENGES FOR SOLID DESICCANT COOLING,Air conditioning and dehumidification systems using solid desiccants have been developed and are finding niche applications in commercial building with special humidity problems or requirements. Ongoing research is being directed at materials and components investigations which have the promise of increasing the performance and reducing the cost of air conditioning systems to the point that they will realize broader application for building environmental control. This technical progress| coupled with intensive societal pressures for limiting the growth of peak electrical demand and release of global warming and ozone destruction gases| suggests that desiccant technology will experience an expanding penetration of the building air conditioning market. 4012,1993,3,3,THE THEORY OF ENERGY RETURN ON INVESTMENT - A CASE-STUDY OF WHOLE TREE CHIPPING FOR BIOMASS IN PRINCE-EDWARD-ISLAND,Industrial societies consume vast quantities of fossil fuel resources| the carbon dioxide released when these fuels are combusted is a major concern because of global warming. ''Energy Return On Investment'' (EROI) is the ratio of energy gain from a resource relative to the energy invested to achieve that gain. EROI analysis shows that the net energy available from fossil fuels decreases as resources are depleted| encouraging a transition to renewable resources which will not be depleted under sustainable management. Renewable resources can reduce net contributions of carbon dioxide to the atmosphere; however| many sources of renewable energy require fossil fuel inputs into their production process. EROI analysis can also be used to determine renewable energy sources with the greatest energy gain| relative to the fossil fuel investment required to achieve that gain. One renewable source of energy with considerable potential for expansion in Canada is wood biomass. A case study of whole tree chipping (WTC) in Prince Edward Island revealed an EROI ratio of wood chip energy gained relative to fuel energy invested of 26.7:1. The major factor affecting the EROI for WTC was transport of the chips to the burning facilities: distance and load size were important components that should be considered when designing new burning facilities. There are some benefits and disadvantages of WTC not captured by EROI analysis that also need to be considered.
4056,1993,2,3,THE TRANSIENT-RESPONSE OF TERRESTRIAL CARBON STORAGE TO A PERTURBED CLIMATE,MODEL simulations suggest that at equilibrium| global warming driven by higher atmospheric concentrations of greenhouse gases will lead to increased terrestrial carbon storage1|2| implying a negative feedback between the global vegetation/soil system and the atmospheric CO2 Concentration. But changes in vegetation and soil type that result in a net release of CO2 to the atmosphere (such as those caused by wildfires) could be more rapid than changes that result in a net increase in terrestrial carbon storage (such as species immigration and soil formation)| so that in its transient response to climate change| the terrestrial vegetation/soil system could be a net source of carbon to the atmosphere. Here we use two general circulation models3|4 to estimate the transient response of the terrestrial surface to a step doubling of atmospheric CO2. We find that vegetation and soil changes could prove to be a significant source of CO2 in the first 50-100 years following a climate warming| increasing the atmospheric CO2 concentration by up to a third of the present level. 2661,1993,5,4,TM-LANDSAT IMAGERY APPLIED TO THE STUDY OF THE IMPACT OF GLOBAL CLIMATE-CHANGE ON A TROPICAL COASTAL ENVIRONMENT DURING THE LAST DEGLACIATION,The discovery and subsequent mapping of an ancient shoreline at 25 m depth in N-E Brazil by TM-Landsat imagery is described. The study area is located on a tectonically stable part of the Brazilian shelf which presently shows a minor uplift rate of 0.2 mm year-1| to the north of Natal in the State of Rio Grande do Norte. This submerged shoreline is characterized by the occurrence of a large number of long beachrock outcrops (> 3 km in length)| observed by diving| which are comparable to their analogues seen on the present-day beaches of the adjacent coast. The good state of preservation of this shoreline and the large number of carbonate rock 'reefs' on it suggest abruptness of a return to transgressive sea-level trend with high growth rates subsequent to a long-lived sea-level relating to the 11000-9000 yr B.P. band. By reviewing high resolution paleoclimatic data from this period| we conjecture that this stillstand could be a consequence of the Younger Dryas cold event in the north Atlantic| which might have also had importance as a driving morphogenetic process for coasts in a global scale.
3966,1993,3,3,TOTAL EQUIVALENT WARMING IMPACT - A MEASURE OF THE GLOBAL WARMING IMPACT OF CFC ALTERNATIVES IN REFRIGERATING EQUIPMENT,Chlorofluorocarbons (CFCs) are important components of refrigeration equipment| plastic for insulation for buildings and appliances| and solvent cleaning processes. The Montreal Protocol to Protect Stratospheric Ozone Layer and recent revisions to the protocol require a rapid phase-out of the production and use of CFCs and a transition to alternative materials and technologies. It is important that the alternative technologies selected do not exacerbate the global warming problem while attempting to preserve stratospheric ozone. A study was conducted to evaluate the total global warming impact of proposed alternatives to CFCs and this paper focuses on the aspects of that study relevant to refrigeration and air-conditioning. The concept of total equivalent warming impact (TEWI) is developed as a measure of the combined global warming impacts of the refrigerant losses to the atmosphere and the CO2 emissions from fossil fuels to generate power to run the refrigeration and air-conditioning systems. Equipment using alternatives to CFCs has lower TEWIs than current systems in almost all cases| with dramatic reductions possible in some applications. 4020,1993,5,4,TROPICAL FOREST CHANGES DURING THE LATE QUATERNARY IN AFRICAN AND SOUTH-AMERICAN LOWLANDS,Arboreal pollen and montane elements of Late Quaternary pollen assemblages from three lacustrine cores (West Cameroon| southeastern Amazonia and central Brazil) are correlated| by the radiocarbon chronology| with other palaeoenvironmental records in Africa and South America. We observe in both continents a well-developed dense forest at 30|000 and 9000 yr B.P. The succession of vegetation types during the Late Quaternary appeared strongly related to the regional conditions: (1) the dense forest was more or less degraded depending on the regions during the last full glacial period (20|000-15|000 yr B.P.); (2) a slow increase of tree elements is evidenced in some areas during the Late Glacial (15|000-10|000 yr B.P.)| whereas short-term fluctuations occurred in central Brazil during the same time; (3) a strong regression of the forest during the middle Holocene (6000-5000 yr B.P.)| in the southern tropical zone of South America| was in opposition to a full forest development in Africa. In both continents two main features characterize the tropical forest evolution: (1) Montane elements developed in the lowlands during the last glacial period and in some southern or northern regions during the early Holocene; and (2) the climate seasonality was enhanced in several regions since 8500-7500 yr B.P. For a tentative explanation| we relate the cold or cool climate| inferred by palaeoecological evidences in the glacial period and glacial-interglacial transition| to polar air-masses reaching more frequently the tropical zone. This interpretation explains the apparent contradiction between the markedly low temperature of the continental lowlands opposed: (1) at 18|000 yr B.P.| to the 1-2-degrees-C lower Sea Surface Temperature of tropical oceans and (2) to the global warming during the late glacial. During the middle and Late Holocene| climate evolution was mainly influenced by the latitudinal shift of the ITCZ positions in July and January and| in South America| by short-term changes of the zonal atmospheric circulation. 3970,1993,4,3,TROPOSPHERIC OZONE AND CLIMATE-CHANGE,Considerable attention has been paid in recent years to photo chemical smog pollution close to the earth's surface and to stratospheric ozone depletion. There is reason to suspect that the next round of scientific concern will be devoted to the perturbations in the ''free troposphere.'' Tropospheric ozone has been building up in many regions of the northern hemisphere. Ozone changes in the upper troposphere will exert a considerable impact on global warming. This could affect moisture levels| cloud amount and distribution| precipitation| and atmospheric dynamics on different scales. This paper analyzes: (1) the physical and chemical processes contributing to changes in tropospheric ozone concentration; (2) the observational evidence of previous ozone change; and (3) results drawn from computer modelling of past and future radiative forcing caused by rising ozone concentrations in the upper troposphere. The solar and longwave radiative model developed by Wang et al. (1 991) was used for calculating the change in radiative forcing to the troposphere-surface system that can be ascribed to changing concentrations in ozone and other greenhouse gases. Nitric oxide emission from aircraft are a prime suspect for the observed increases in upper tropospheric ozone. The inference can be drawn that a radiative forcing of 0.2 to 0.35 Wm-2 Will result from a doubling of aircraft emissions over the next two decades. This will amount to 10 to 25 percent of the radiative forcing attributable to CO2 alone for the same period. The effect of doubling aircraft emissions will increase as stratospheric ozone concentrations recover from the recent buildup of harmful chlorofluorocarbons. A large fraction of the radiative forcing that occurred during the 1970 to 1990 period can be attributed to increases in tropospheric ozone as opposed to increases in other greenhouse gases. 3959,1993,4,3,UNCERTAINTIES IN CARBON-DIOXIDE RADIATIVE FORCING IN ATMOSPHERIC GENERAL-CIRCULATION MODELS,Global warming| caused by an increase in the concentrations of greenhouse gases| is the direct result of greenhouse gas-induced radiative forcing. When a doubling of atmospheric carbon dioxide is considered| this forcing differed substantially among 15 atmospheric general circulation models. Although there are several potential causes| the largest contributor was the carbon dioxide radiation parameterizations of the models. 3955,1993,3,4,UNITED-STATES DEMILITARIZATION AND GLOBAL WARMING - AN EMPIRICAL-INVESTIGATION OF THE ENVIRONMENTAL PEACE DIVIDEND,In the paper input-output methods are used to generate ballpark empirical estimates of the implications for global warming of the projected demilitarization of the US federal budget. The impact is found to be qualitatively ambiguous| and highly sensitive to the manner in which the funds saved are distributed. The effect is adverse where the budgetary savings are used to fund economy-wide cuts in personal taxation and/or deficit reduction. In other cases the effect may be neutral or beneficial. 2686,1993,4,3,USE OF GENERAL-CIRCULATION MODEL OUTPUT IN THE CREATION OF CLIMATE-CHANGE SCENARIOS FOR IMPACT ANALYSIS .1.,Many scientific studies warn of a rapid global climate change during the next century. These changes are understood with much less certainty on a regional scale than on a global scale| but effects on ecosystems and society will occur at local and regional scales. Consequently| in order to study the true impacts of climate change| regional scenarios of future climate are needed. One of the most important sources of information for creating scenarios is the output from general circulation models (GCMs) of the climate system. However| current state-of-the-art GCMs are unable to simulate accurately even the current seasonal cycle of climate on a regional basis. Thus the simple technique of adding the difference between 2 x CO2 and 1 x CO2 GCM simulations to current climatic time series cannot produce scenarios with appropriate spatial and temporal details without corrections for model deficiencies. In this study a technique is developed to allow the information from GCM simulations to be used| while accommodating for the deficiencies. GCM output is combined with knowledge of the regional climate to produce scenarios of the equilibrium climate response to a doubling of the atmospheric CO2 concentration for three case study regions| China| Sub-Saharan Africa and Venezuela| for use in biological effects models. By combining the general climate change calculated with several GCMs with the observed patterns of interannual climate variability| reasonable scenarios of temperature and precipitation variations can be created. Generalizations of this procedure to other regions of the world are discussed.
3978,1993,3,4,UTILIZATION OF CARBON-DIOXIDE FROM FOSSIL-FUEL - BURNING POWER-PLANTS WITH BIOLOGICAL-SYSTEMS,Physical-chemical processes for the capture and sequestration of CO2 from fossil fuel-fired power plant flue-gases are very expensive. Biological processes for CO2 utilization involve plant photosynthesis and conversion of the biomass to fuels| with no net CO2 production. Terrestrial plants cannot utilize flue gas CO2 directly. Only submerged aquatic plants| particularly microalgae| can utilize CO2 from power plant flue gases in a practical process. Microalgae have the potential for achieving high productivities and can be converted to gaseous and liquid fuels. A-preliminary cost-analysis of such a process is presented that suggests that| if high productivities are achievable| overall costs would compare favorably with alternative physical-chemical processes for flue gas CO2 capture and sequestration| but would be higher than CO2 mitigation with terrestrial plants. Microalgae CO2 utilization systems would be most applicable where land and water (seawater| brackish) resources| not readily utilized by agriculture| are available. 4065,1993,4,4,WATER-VAPOR AND ITS ROLE IN THE EARTHS GREENHOUSE,This paper examines the role of water vapour as a greenhouse gas and discusses its role in the evolution of the atmospheres of Venus| Earth and Mars. The paper focuses on how the greenhouse effect operates on Earth and describes the feedback between temperature and water vapour that is thought to play a key role in global warming induced by increasing concentrations of carbon dioxide. A method for analysing the contribution of water vapour to the greenhouse effect using satellite observations is discussed. It is shown how this contribution varies in a directly proportional way with the amount of water vapour vertically integrated through the column of the atmosphere. Based on the results obtained from the analyses of satellite data| it is established that the sensitivity of the greenhouse effect to changing sea surface temperature is not uniform over the globe and is significantly greater over warmer oceans. The relevance of the results to the water vapour feedback is discussed. 2615,1994,4,3,A HISTORICAL REVIEW OF EARLY INSTITUTIONAL AND CONSERVATIONIST RESPONSES TO FEARS OF ARTIFICIALLY INDUCED GLOBAL CLIMATE-CHANGE - THE DEFORESTATION-DESICCATION DISCOURSE| 1500-1860,Systematic notions of significant human impacts on regional and global climate change and species extinctions developed first in the French and British colonial empires. Building on classical Greek theories linking deforestation to rainfall decline the colonial climatic theorists were stimulated by the Newtonian thinking of Stephen Hales and his disciples. The new climate theories led to pioneering forest protection schemes in Tobago| St Vincent| St Helena| Mauritius and western India where the East India Company actively promoted conservation. The Royal Society of Arts| the Academie des Sciences and the Royal Geographical Society all acted as institutional mechanisms for encouraging forest protection based on feats of climate change| long before early environmentalism developed in the United States.
3839,1994,2,4,A METHODOLOGY FOR THE EVALUATION OF GLOBAL WARMING IMPACT ON SOIL-MOISTURE AND RUNOFF,This paper presents a numerical evaluation of the variability of soil moisture and direct surface runoff due to global warming. An analytical model of the soil moisture balance based on our previous work is used to evaluate the probability distribution of the soil moisture concentration and resulting surface runoff. The input of hydroclimatic values is based on the approach suggested by C.W. Richardson in 1981. Our results show that not only the mean of the distribution of both soil moisture and runoff change| as expected| but that the variability of the values around the means also changes. The results of our research have immediate applications on the planning of reservoir operation for irrigation demands and evaluation of the change in surface runoff expected due to global warming. 3871,1994,2,4,A NOTE ON THE REPRESENTATION OF STERIC SEA-LEVEL IN MODELS THAT CONSERVE VOLUME RATHER THAN MASS,This note discusses the representation of steric sea level in ocean circulation models. Changes in steric sea level are caused when changes in the density of the water column imply an expansion or contraction of the column. Models usually intake the Boussinesq approximation and conserve volume| rather than mass| and so do not properly represent expansion or contraction. This means that although expansion/contraction is included in the equation of state| it is not accounted for by the model dynamics. In this note| we examine the equation governing the time evolution of the sea level displacement. It is shown that requiring conservation of mass| rather than volume| introduces a new term to this equation. A simple example is used to show the relationship of the new term to the surface buoyancy flux. The equilibrium response to the new term has two parts. One part consists of the Goldsbrough and Stommel gyres| for which| in the ocean interior| vortex stretching due to the local expansion/contraction of the water column is balanced by changes in planetary vorticity. The other part corresponds to the ''inverse barometer.'' The effect is to adjust sea level by a globally uniform but time-varying factor| determined by the net expansion/contraction of the global ocean. Since this correction is globally uniform| it has no dynamical significance. Both the Goldsbrough/Stommel gyres and the inverse barometer solution are missing from models as currently formulated. This does not represent a serious error. However| if comparison is made with observations of sea level| model-calculated sea level should be adjusted by a globally uniform| time-varying factor| determined by the net expansion/contraction of the global ocean. This would be important for assessing the likely rise in sea level in response to global warming. 3853,1994,4,4,A SIBERIAN VEGETATION MODEL-BASED ON CLIMATIC PARAMETERS,A model for predicting the spatial distribution of the major vegetation zones in Siberia is developed from bioclimatological considerations. Driving variables are growing degree-days (5 degrees C base)| Budyko's dryness index| and Conrad's continentality index. Because these indices reflect the underlying climatic factors determining plants' requirements for warmth| drought resistance| and cold tolerance| they define the main features of vegetation zonation. Climatic inputs (monthly mean temperature| precipitation| vapor pressure| cloudiness| and albedo) are obtained from a global climatic database| supplemented by additional weather stations in Siberia; resolution is 0.5 degrees longitude by 0.5 degrees latitude. The performance of the model is examined by comparing our Siberian vegetation predictions with the landscape map of the USSR by Isachenko| a map that was not used for model development. The patterns of vegetation predicted by the Siberian vegetation model generally match well with the vegetation patterns on Isachenko's map. The general locations of all vegetation zones are predicted correctly. This visual impression is also borne out statistically| with K-statistics for judging agreement between the maps showing good agreement (0.55 < kappa < 0.7) at all scales of comparison (from 0.5 degrees by 0.5 degrees pixels to 5 degrees by 5 degrees blocks of pixels). The model is also useful for estimating the change in equilibrium conditions due to hypothesized events such as CO2-induced global warming| for retrospective comparisons using the paleorecord| and for carbon budget assessment. 3897,1994,3,2,A STRATEGY TO REDUCE CO2 EMISSIONS FROM HYDROCARBON-FUELED POWER-PLANTS BY PRECOMBUSTION REFORMING AND DEEP-OCEAN DISCHARGE OF CO2,A process to reduce atmospheric CO2 emissions from hydrocarbon-fueled power plant is proposed. The fuel is reformed into a mixture of hydrogen and CO2 before combustion takes place. These gases are subsequently separated by preferential absorption or by differential phase changes. Thereafter| hydrogen replaces the original fuel for power generation. The liquefied CO2 is discharged into the deep ocean. Water depths of about 500 m appear to be favorable from logistic and thermoeconomic standpoints. Calculations for a 500 MW methane power plant| retrofitted with the proposed system| indicate moderate power and cost penalties. The relative impact of a widespread implementation of this global warming countermeasure is assessed| and the advantages of moderate hydrocarbon consumption trends| as well as of high CO2 discharge fractions are highlighted. This latter point may indicate the need for sweeping changes| such as the establishment of hydrogen-based economies if global warming is to be avoided. 3886,1994,3,4,ABATEMENT OF N2O EMISSIONS PRODUCED IN THE ADIPIC ACID INDUSTRY,Apidic acid (AA) manufacture results in the production of ca. 1 mole of nitrous oxide (N2O) per mole of AA. Emissions of N2O by the AA industry currently account for about 5-8 percent of the worldwide anthropogenic N2O emissions (after accounting for N2O abated by some manufacturers). Even though this N2O does not make a major contribution to global warming and ozone depletion| major AA producers worldwide have agreed to substantially reduce these emissions by 1996-98. Producers have formed an inter-industry group to share information on technologies being developed for N2O control. Technology options being studied by DuPont (and by others) include thermal destruction| recycling| and catalytic decomposition. 3865,1994,3,3,ADVANCED COAL-FIRED LOW-EMISSION BOILER SYSTEMS,As part of the Combustion 2000 Program of the US Department of Energy| advanced low-emission boiler systems are being developed for future coal-fired power plants. These plants will be extremely clean| highly efficient and economic| by employing emerging and state-of-the-art technologies. The emissions of SO.| NO(x) and particulates from the plants will be much lower than the current new source performance standards (NSPS)| and the net plant efficiency of generating electricity will be higher than that of today's pulverized-coal-fired utility plants. The high plant efficiency results in low fuel use and reduced emission of gases (CO2) associated with global warming. At present| engineering development of advanced systems is being conducted by three industry teams. The development work includes new emission control technologies| state-of-the-art boiler designs and low-temperature heat recovery systems for improved plant efficiencies| systems for improved ash disposability and reduced waste generation| and optimum system integration and plant controls. The technologies considered by these teams for low-emission boiler systems are discussed. 3896,1994,2,3,AGRICULTURAL POLICY| CLIMATE-CHANGE AND FOOD SECURITY IN MEXICO,This paper describes how variations in agricultural policy and climatic conditions have influenced maize production and food security in 20th-century Mexico. We describe the Mexican food system today and how economic policy has influenced food output in efforts to attain food security based on the goal of national self-sufficiency. We examine the impact of climate variability on agricultural production; the ways in which agricultural policy has interacted with climate to change vulnerability to environmental and social change and the implications of global warming for the future of Mexican agriculture. Finally| we discuss the implications of the changing economic environment as Mexico has opened its economy - for example| through the North American Free Trade Agreement. Our goal is to provide a context for thinking about the implications of two types of global change for Mexico - the internationalization of economies and the widespread transformation of the environment. 2647,1994,3,3,AGRICULTURES SHARE IN THE EMISSION OF TRACE GASES AFFECTING THE CLIMATE AND SOME CAUSE-ORIENTED PROPOSALS FOR SUFFICIENTLY REDUCING THIS SHARE,This paper discusses agriculture's share in the world-wide emissions of climate-affecting gases and in the global warming potential (GWP). Proposals also are presented to reduce these emissions adequately| using a cause-oriented approach. Largely due to the fertilization and cultivation of agriculture as well as the burning of biomass| agriculture has a very high share in the anthropogenic emissions of NH3| N2O | CH4 and CO at >95%| 81%| 70% and 52%| respectively| while its share in the NO(x) and CO2| emissions is relatively small at 35% and 21%. The GWP of agriculture| based on annually 16.1 x 10(9) tons of CO2| approaches 63% of the GWP of the energy sector or 80% of the GWP of its CO2 emissions. At 34% and 32%| respectively| the main originators in the GWP of agriculture would seem to be CO2 (changing land use) and CH4 (animal husbandry/rice cropping/biomass burning) followed at 15% by NO2 (technical and biological N fixation/(cultivation and recultivation/biomass burning) and 10% and 9% by CO and NO(x). The GWP of 3 German dairy cows corresponds with 13.2 tonnes CO2 per year the GWP of two average German automobiles. However| the ozone-destroying effect of N2O and the climate-relevant effects of NH3 are not yet included here. As with the therapy for other 'modern' boundary-crossing environmental damages| such as acidification or eutrophication| global climate change therapy likewise needs a therapy for the respective effects of reactive compounds of carbon| nitrogen| phosphorous| and sulfur also emitted by agriculture: Proposals for reducing these emissions within the agricultural sector include need-oriented plant| animal and human nutrition| more efficient external and internal nutrient recycling| the cessation of further clearing by burning| along with intensified afforestation mainly in the tropics| targeted measures to reduce nutrient losses/emissions| and measures for more efficient use of nutrients in plant| animal and human nutrition. These measures would at best result in reduced pollution of the global environment but not put it to an end. Decisive| therefore| is both the tolerable extent of mankind and its long-term sustainable way of life.
3826,1994,3,3,AIRPORT REVOLUTION,Air quality regulations are encouraging the use of electric vehicles at urban airports across the United States. In many ways| airports offer an ideal application for EVs| given the short distances and predictable routes that airport vehicles typically travel. Even considering the emissions from power plants supplying electricity to an airport| the replacement of internal combustion vehicles with comparable electric-powered vehicles significantly reduces pollutants that contribute to such environmental problems as smog| haze| and global warming. Through EPRI's Airport Electrification Project| utilities in urban areas are working in partnership with their airport customers to devise strategies for the cost-effective implementation of EVs. 3859,1994,3,3,ALKALINE FALLING-FILM FUEL-CELL - A BREAKTHROUGH IN TECHNOLOGY AND COST,The work described in this paper was oriented towards fuel cells for practical applications| but mainly presents data obtained using half-cells. The economic significance of these data is discussed| together with the technical concept of fuel cell power stations and for transportation applications. The proposed fuel cell will generate power at much lower costs than conventional power plants| and a zero-emission vehicle with fuel cells will operate at lower fuel cost than a car with an internal combustion engine. The simple falling-film process leads to high power densities (6 kW/l) and low cost. The details given are valid for the use of hydrogen produced from fossil energy sources. Concentrated CO2| a byproduct of this technology can be stored in discussed oil and gas fields at a very low cost to avoid global warming. Thus| this 'down-to-earth' hydrogen technology is as free from CO2 emissions as solar-hydrogen technology. 3801,1994,2,4,AN ECONOMIC-ANALYSIS OF POTENTIAL IMPACTS OF CLIMATE-CHANGE IN EGYPT,Projections of climate impacts on crop yields simulated for different General Circulation Model (GCM) scenarios are used| in a recursively dynamic general equilibrium framework| to account for potential economy-wide impacts of climate change in Egypt| Comparing impact projections to those obtained under a reference| business-as-usual| scenario assuming some moderate changes in the political| economic or technological spheres| indicates that global warming has potentially negative effects. The analysis is based on a global assessment of potential climate change-induced variations in world commodity production and trade. The Egyptian agricultural sector| and the non-agricultural sector to a lesser extent| are projected to be increasingly less self-sufficient. Specific potential adverse impacts are identified. The simulation results show that high-cost adaptation measures involving major changes in the agricultural system and practices may mitigate these adverse impacts. Stimulating economic development of the rural areas and creating appropriate conditions for effective diffusion and development of technologies - particularly for the agricultural sector - would seem a desirable strategy. Perhaps| more importantly| the simulation results show that the assumption of exogenously determined technological progress may be inappropriate| in which case the potential adverse impacts of a future warming of the global climate are likely to be fewer than is indicated in this study - if prevailing constraints on productivity growth in the major food and feed grains are 'released' by endogenous advances in technology. 3814,1994,3,3,AN EVALUATION OF AUTOTROPHIC MICROBES FOR THE REMOVAL OF CARBON-DIOXIDE FROM COMBUSTION GAS STREAMS,Carbon dioxide is a greenhouse gas that is believed to be a major contributor to global warming. Studies have shown that significant amounts of CO2 are released into the atmosphere as a result of fossil fuels combustion. Therefore| considerable interest exists in effective and economical technologies for the removal of CO2 from fossil fuel combustion gas streams. This work evaluated the use of autotrophic microbes for the removal of CO2 from coal fired power plant combustion gas streams. The CO2 removal rates of the following autotrophic microbes were determined: Chlorella pyrenoidosa| Euglena gracilis| Thiobacillus ferrooxidans| Aphanocapsa delicatissima| Isochrysis galbana| Phaodactylum tricornutum| Navicula tripunctata schizonemoids| Gomphonema parvulum| Surirella ovata ovata| and four algal consortia. Of those tested| Chlorella pyrenzoidosa exhibited the highest removal rate with 2.6 g CO| per day per g dry weight of biomass being removed under optimized conditions. Extrapolation of these data indicated that to remove CO2 from the combustion gases of a coal fired power plant burning 2.4 x 10(4) metric tons of coal per day would require a bioreactor 386 km(2) x 1 m deep and would result in the production of 2.13 x 10(5) metric tons (wet weight) of biomass per day. Based on these calculations| it was concluded that autotrophic CO2 removal would not be feasible at most locations| and as a result| alternate technologies for CO2 removal should be explored. 3920,1994,4,4,AN INTEGRATED MODELING OF STOICHIOMETRY AND BIOKINETICS OF ANAEROBIC PROCESSES,The objective of this paper was to present an integrated modeling approach to biokinetics and stoichiometry of anaerobic treatment processes. A software system has been developed to calculate bacterial yield coefficients from stoichiometry under different anaerobic bioprocess conditions. Kinetic constants| i.e.| the reaction rate constant and Monod half-velocity coefficient| were determined from batch experimental data using Conreg| a software system for constrained nonlinear regression. Additional experiments were performed to evaluate the usefulness of the Inhibition Coefficient model to predict toxicity of ammonia and methylene chloride in anaerobic batch systems. The integrated approach to biokinetics and stoichiometry and the software developed for this purpose should help engineers quickly evaluate a wide variety of design options for anaerobic treatment systems under both toxic and non-toxic conditions. Other useful applications include prediction of natural rates of methane (a gas causing global warming) formation in rice paddies. 3880,1994,3,3,AN OPINION ON THE GLOBAL IMPACT OF MEAT CONSUMPTION,The topic of vegetarian nutrition can be approached from several angles| perhaps one of the most important being the impact that meat production is having on the underdeveloped world| where ancient rain forests are being cleared to provide land for cattle grazing. Debt-burdened countries are turning over agricultural land to raise cattle and grains for feeding the cattle. These practices have resulted in less available land for the production of food| global warming because of the practices used for deforestation| exhaustion of the world's water supply| and other adverse effects on the health of the world. The consumption of meat for food is taking a toll on the consumer and the health of the world's poorest people. It is also contributing to an expanding need for foreign aid and growing world hunger. 3937,1994,5,4,ANCIENT REEF ECOSYSTEM EXPANSION AND COLLAPSE,Platform carbonate and| particularly| reef ecosystem development (with reefs representing the acme of carbonate platform growth) were highly cyclical in early to mid Paleozoic time| especially in relation to known or postulated times of global warming or cooling. These cycles do not appear to correspond to postulated 26 Ma rhythms seen in diversity patterns| nor were they regular. There were major periods of worldwide reef expansion (e.g. mid-Silurian-Late Devonian)| corresponding to global warming well above present day norms| and periods of complete global reef collapse (e.g.| mid-Cambrian to mid-Ordovician| Late Devonian) corresponding to global perturbations. At times of major reef expansion in the Paleozoic| areas covered by equatorial reef and inter-reef carbonate platforms are conservatively estimated to have periodically exceeded 5 million sq. km| nearly ten times that in the modern ocean. At times of global reef collapse| e.g. the Famennian (Late Devonian)| reef complexes were completely absent or| at best| covered < 1000 sq. km. The chief factors relating to periodic collapse and mass extinction of reef biotas appear to be related to climatic change and possibly ocean anoxic events| in turn as a response to large scale| geologically disruptive factors such as plate collisions| plate movement across equatorial belts and volcanism. Stress ''signals'' in Cambrian through Cretaceous reef ecosystems appear to be comparable to those of today: whether these relate to physical versus biological stress is uncertain. Reef stress is evident in globally reduced areas and thicknesses of reef carbonate production| the absence of large scale barrier reef systems and reduction to smaller patch reef complexes (or| periodically| following mass extinctions| no reefs at all)| reduced species and genus diversity| small skeletons or colonies| limited or no biotic zonation along reef transects| and arrested succession and ecologic replacement of complex| more highly evolved taxa by ''simpler''| stress-resistant disaster taxa at the genus to ordinal (or even phylum) level. 3811,1994,3,4,ANODE EFFECTS| PFCS| GLOBAL WARMING| AND THE ALUMINUM-INDUSTRY,As concerns grow about the role that perfluorinated carbon compounds (PFCs) play in global warming| the aluminum industry is voluntarily exploring ways of reducing the volumes of CF4 and C2F6 generated during Hall-Heroult electrolysis. As these gases are produced only during anode effects| which are undersirable for other production reasons as well| aluminum producers are aggressively examining ways to reduce the number of anode effects that occur as well as their duration.
3846,1994,3,3,ANTHROPOGENIC EMISSIONS OF NITROUS-OXIDE (N2O) FROM EUROPE,Anthropogenic nitrous oxide (N2O) emissions from Europe| and Asiatic Turkey| are estimated for the period 1960-2040. Between 1960 and 1985 these emissions are found to have doubled to 1059 kton N2O-N/year. For future emissions three scenarios are defined: a no reduction scenario| where current trends continue; an acid reduction scenario| reflecting the implementation of maximum feasible technology to reduce acidification; and an optimistic scenario| in which both N2O and acidifying emissions are strongly reduced. In the no reduction and acid reduction scenario anthropogenic N2O emissions increase to 1199 and 1274 kton N2O-N/year by 2040| respectively. Thus technologies to reduce acidification are calculated to cause a net increase in N2O emissions. In the optimistic scenario 534 kton N2O-N is emitted annually from 2020. A climate goal| aiming to limit future global warming to 0.1-degrees-C/decade| is calculated to require a stabilization of anthropogenic European emissions at 221 kton N2O-N/year (based on a pro rata contribution of greenhouse gases to emission reductions| and worldwide equal per capita N2O emissions). In all three scenarios N2O emissions exceed 221 kton N2O-N/year. In order to meet their goal| countries need to cut anthropogenic emissions by 59-90% relative to 1985| and by 40-63% relative to 2040 in the optimistic scenario. 3845,1994,4,4,APPLICATION OF A FOURIER-TRANSFORM IR SYSTEM FOR MEASUREMENTS OF N2O FLUXES USING MICROMETEOROLOGICAL METHODS| AN ULTRALARGE CHAMBER SYSTEM| AND CONVENTIONAL FIELD CHAMBERS,Measurements of the sources and sinks of biogenic trace gases such as N2O and CH4 from terrestrial ecosystems are important in explaining and predicting the influence of these gases on global warming. Because of their biological origins the fluxes of these gases often show high spatial and temporal variation. Traditional methods of flux measurement use different types of field chambers or micrometeorologically based methods. These methods have several shortcomings and may not always be applicable to flux measurements of trace gases such as N2O or CH4. Fourier transform infrared (FTIR) spectroscopy| due to its path-integrating and multicomponent nature| shows unique potential for the measurement of fluxes of greenhouse gases from various ecosystems. To assess this potential| we have used a medium resolution (1 cm-1) FTIR spectrometer to test its suitability for area-integrated measurements| simultaneous multicomponent measurements| and continuous real-time measurements of trace gas fluxes. We have tested three different configurations: a conventional field chamber where the FTIR is used to continuously and simultaneously monitor the concentration changes of several gases| a megachamber method using a large tent as field chamber with the FTIR optical path within the chamber| and a micrometeorological flux gradient method. The three configurations are described and discussed and their performance is demonstrated in measurements of fluxes of N2O from a fertilized. grassland and CH4 from a forest soil. 3895,1994,3,4,APPLYING ENVIRONMENTAL LIFE-CYCLE ANALYSIS TO MATERIALS,The life-cycle analysis (LCA) of products is essentially the LCA of materials: both are concurrently and interdependently analyzed and assessed according to their environment effects. This approach provides a framework to measure the extrinsic environmental properties of materials. In the following| three properties-gross energy requirement| global-warming potential| and solid-waste burden-are broadly discussed for steel| aluminum| and polyethylene. The environmental profiles are then applied to assess the use of alternative materials in terms of the LCA of an automotive component. Given the possibility of a substantial variation in results| one must be careful with the scoping and assessment of LCA. Despite the limitations| it provides a useful map for improving environmental compatibility and performance. 3792,1994,4,4,ASSESSING THE ABILITY OF THE KOPPEN SYSTEM TO DELINEATE THE GENERAL WORLD PATTERN OF CLIMATES,The Koppen climate classification system [Koppen| 1923] is a scheme that provides an objective numerical basis for defining regional climatic types based on temperature and precipitation. Through the years it has been used as a scientific and teaching tool for prescribing the general world pattern of climates. Here for the first time an evaluation of the system is performed by employing coextensive temperature and precipitation data over the N. Hemisphere for the last 140 years. First the global pattern of climate type sensitivity is obtained. From this pattern it is discovered that several climate types exhibit a rather strong variability. Since all climate types depend on temperature we then tested whether or not the above variability is due to the fact that over the last 140 years the global climate system exhibits a well documented positive temperature trend known as global warming. We found that the Koppen system is rather insensitive to the observed global warming and concluded that overall the system performs rather poorly over Europe and Asia whereas it appears adequate over N.America and N.Africa. 3847,1994,4,4,ATMOSPHERIC LIFETIME| ITS APPLICATION AND ITS DETERMINATION - CFC-SUBSTITUTES AS A CASE-STUDY,The concept of atmospheric lifetime| its application in atmospheric chemistry| and its use in defining environmental acceptability indices such as the ozone depletion potential and the global warming potential are described. The determination of the atmospheric lifetime from laboratory measured chemical kinetic and photochemical parameters is highlighted. A brief description of the laboratory methods used to determine kinetic parameters and the difficulties encountered in measuring them are given. In all these descriptions and discussions| chlorofluorocarbons (CFCs) and their substitutes are used as examples. The environmental acceptability of the currently proposed CFC substitutes| the hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are discussed. Lastly| the question is raised: Should atmospheric lifetime be used as an index of accept ability? 2634,1994,2,4,AVIAN COMMUNITY DYNAMICS ARE DISCORDANT IN-SPACE AND TIME,The threat of global climate change challenges community ecologists to predict long-term and continental-scale changes in the structure of ecological communities. However| the vast majority of studies have been done at small temporal and spatial scales. Can conclusions about community dynamics based on small-scale studies be extrapolated to larger spatial and temporal scales? We compared the dynamics of regionally coexisting bird species over different spatial and temporal scales using data from the North American Breeding Bird Survey. We found that such extrapolation is suspect. Bird species that had similar local year-to-year population fluctuations did not have similar long-term population trends. Additionally| species that had similar population dynamics in one region rarely exhibited similar dynamics in the different regions where they occurred together.
3794,1994,3,3,BASIC EXPERIMENTAL RESULTS OF LIQUID CO2 INJECTION INTO THE DEEP-OCEAN,CO2 disposal in the deep ocean is expected to be an effective option for mitigating the increase in CO2 on the earth. We have investigated the behaviour of liquid CO2 using test facilities which can simulate the pressure and temperature of the deep ocean. Phase equilibrium data of the CO2-seawater system and the conditions of CO2 clathrate formation were confirmed. In addition| we measured the pH value of seawater saturated with CO2 at high pressure. The data presented in this paper are considered indispensable for evaluating the possibility of CO2 disposal in the deep ocean. 3899,1994,2,4,BENTHIC AMPHIPOD COMMUNITY IN THE NORTHERN BERING SEA - ANALYSIS OF POTENTIAL STRUCTURING MECHANISMS,The age class structure of ampeliscid populations is determined largely by competition for space. Population densities of the various ampeliscid species are regulated by a balance between required carbon flux rates to the seafloor| predation rates| competition for space and reproductive potential. The largest taxa require high organic matter input and low predation rates to mature and reproduce. Reductions in organic matter flux favor smaller taxa. Low predation rates favor larger taxa| which can out-compete the smaller taxa for available space. High predation rates favor smaller taxa| which have a higher reproductive rate and are therefore more effective colonizers. The above factors can explain the relative concentrations of Ampelisca macrocephala| Ampelisca birulai and Byblis spp.| the most abundant ampeliscids in the northern Bering Sea. Elevated predation losses to gray whales will depress the density of the large-sized A. macrocephala populations and increase the density of the smallest species| A. birulai. Global warming should elevate ampeliscid food requirements| and may also lead to elevated predation rates| both selecting for smaller species. 3824,1994,2,3,BEYOND GLOBAL WARMING - ECOLOGY AND GLOBAL CHANGE,While ecologists involved in management or policy often are advised to learn to deal with uncertainty| there are a number of components of global environmental change of which we are certain-certain that they are going on| and certain that they are human-caused. Some of these are largely ecological changes| and all have important ecological consequences. Three of the well-documented global changes are: increasing concentrations of carbon dioxide in the atmosphere; alterations in the biogeochemistry of the global nitrogen cycle; and ongoing land use/land cover change. Human activity-now primarily fossil fuel combustion-has increased carbon dioxide concentrations from similar to 280 to 355 mu L/L since 1800; the increase is unique| at least in the past 160 000 yr| and several lines of evidence demonstrate unequivocally that it is human-caused. This increase is likely to have climatic consequences-and certainly it has direct effects on biota in all Earth's terrestrial ecosystems. The global nitrogen cycle has been altered by human activity to such an extent that more nitrogen is fixed annually by humanity (primarily for nitrogen fertilizer| also by legume crops and as a byproduct of fossil fuel combustion) than by all natural pathways combined. This added nitrogen alters the chemistry of the atmosphere and of aquatic ecosystems| contributes to eutrophication of the biosphere| and has effects on biological diversity in the most affected areas. Finally| human land use/land cover change has transformed one-third to one-half of Earth's ice-free surface. This in and of itself probably represents the most important component of global change now and will for some decades to come; it has profound effects on biological diversity on land and on ecosystems downwind and downstream of affected areas. Overall| any clear dichotomy between pristine ecosystems and human-altered areas that may have existed in the past has vanished| and ecological research should account for this reality. These three and other equally certain components of global environmental change are the primary causes of anticipated changes in climate| and of ongoing losses of biological diversity. They are caused in turn by the extraordinary growth in size and resource use of the human population. On a broad scale| there is little uncertainty about any of these components of change or their causes. However| much of the public believes the causes-even the existence-of global change to be uncertain and contentious topics. By speaking out effectively| we can help to shift the focus of public discussion towards what can and should be done about global environmental change. 3931,1994,2,4,BIODIVERSITY OF CORAL-REEFS - WHAT ARE WE LOSING AND WHY,Coral reefs are threatened by numerous anthropogenic impacts| some of which have already had major effects worldwide. These unique tropical environments harbor a high diversity of corals| reef invertebrates| fish and other animals and plants. In most taxa| the species diversity of reef-associated organisms is poorly understood because many of the species have yet to be collected and described. High coral mortality has been associated with natural events such as hurricanes| predator outbreaks and periods of high temperature| but has also resulted from excess nutrients in sewage and from specific pollutants. Reef corals and associated organisms are also threatened by the possibility of global warming which will result in rising sea levels and periods of increased temperature stress| and which may also bring increased storm frequency and intensity. Although the recent extensive episodes of coral bleaching in the Caribbean and eastern Pacific cannot be causally related to global warming at this time| the close link between bleaching and temperature suggests that global warming will result in severe changes in coral assemblages. Major reef destruction has followed outbreaks of the predatory seastar Acanthaster planci in the Pacific. Although this is considered part of a natural disturbance cycle| there are indications that altered land use patterns and reduction of predators on this seastar by human activities may have increased the severity of outbreaks. Recreational and commercial use of reefs has also increased| and has caused extensive damage| especially near areas of high population density. One of the most obvious and widespread losses to reef biota is the reduction in fish populations from intense overfishing in most reef areas of the world. Coasts without adequately managed reefs have suffered intense overfishing for both local and export purposes| to the point where the positive effects of fish on those reefs have been compromised. The combination of these destructive factors has altered reefs in all localities| and many that were once considered protected by distance and low population density are now being exploited as well. On the positive side| improved understanding of ecological processes on reefs combined with concerted conservation efforts have managed to protect some extensive areas of reef for the future.
2625,1994,2,4,BIOMASS ALLOCATION OF MONTANE AND DESERT PONDEROSA PINE - AN ANALOG FOR RESPONSE TO CLIMATE-CHANGE,We measured aboveground biomass allocation of Pinus ponderosa on hydrothermally altered andesite in montane and desert climates. Thus substrate was held constant while climate varied. Trees from montane climates had higher leaf mass per unit cross-sectional area of sapwood (functional conducting xylem) than trees from desert climates| suggesting that a functional response to differences in climate had occurred. Our results also indicate that sapwood mass:leaf mass ratios of P. ponderosa may increase approximate to 50% with a 5 degrees C change in mean growing-season temperature| approximately the difference between our montane and desert sites. High proportional allocation of biomass to sapwood may improve water relations of P. ponderosa| but because sapwood contains living parenchyma| respiratory costs may be high. Site-specific regression equations were used to calculate aboveground biomass allocation for simulated montane and desert trees with the same diameter at breast height| dbh. Simulated montane trees were 46-52% taller than desert trees| and montane trees 10 cm in dbh had twice the total aboveground mass of desert counterparts. Simulated 50-cm montane and desert trees were almost identical in total mass| even though the montane tree was 46% taller. The predicted proportion of biomass allocated to bole sapwood increased with size for both montane and desert models; however| the 50-cm desert model contained 8% more total sapwood mass than the taller montane model. Total biomass of branches was similar for paired models of all size classes; however| biomass of primary and secondary branches differed considerably. The 50-cm desert model had twice as much biomass in primary branches in comparison to the montane model| whereas the montane model had 3 times more biomass in secondary branches than the desert model. For 10-cm trees of the desert and montane models 29 and 33% of the biomass were leaves| respectively. In larger trees| leaf allocation decreased to 5 and 7% for desert and montane models| respectively. The effects of climate on biomass allocation| such as reported here| and corresponding changes in whole-plant assimilation rates must be incorporated into growth-response models used to predict future fluctuations in forest productivity due to global climate change.
3898,1994,4,3,CARBON EXPORT FROM CONTINENTAL SHELVES| DENITRIFICATION AND ATMOSPHERIC CARBON-DIOXIDE,To investigate the long-term role of continental shelves| a global carbon box model which included continental shelf waters and sediments| ocean surface waters| the deep-sea and the atmosphere was constructed. With nitrogen limiting oceanic primary production| the model included balanced nitrogen inputs (from the continents and atmosphere) and losses (primarily via denitrification). Carbon export to the deep-sea (without deposition or burial in sediments) affected the average conditions found in the shelves but did not influence atmospheric carbon dioxide content. Similarly| redistribution of nitrogen inputs to the surface oceans had no major effect on atmospheric pCO(2). Tn contrast| atmospheric pCO(2) changes were caused by redistribution of denitrification rates between the continental shelf sediments and the deep-sea. When denitrification in continental shelf sediments increased from 10% of the total oceanic rate to 95%| shelf denitrification removed more nitrogen from the surface ocean| supporting less of a flux of sinking particulate carbon (SPC) into the deep-sea. This increased atmospheric pCO(2) by II ppm. When overall rates of nitrogen cycling were decreased by half to today's level| the atmospheric pCO(2) content was increased by an additional 5 ppm. These effects may have influenced the ice-ages. As the glaciers expanded| shelf denitrification was lessened by the reduction in continental shelf area. Moving the site of denitrification from the shelves to the deep-sea would have increased both oceanic new production and the SPC flux into the deep-sea| thereby lowering atmospheric pCO(2) levels during the initial periods of glaciation. Increased new production may have enhanced water column denitrification which in turn lowered the oceanic inorganic nitrogen content and restricted oceanic productivity. With less oceanic nitrogen| water column denitrification would have decreased resulting in a more equal proportioning of the total removal rate between the deep-sea and the continental shelves. Also| the total cycling rate of nitrogen would have lessened. In addition| inundation of the continental shelves during glacial retreat would have increased shelf denitrification. From the model| these trends would have released CO2 from the ocean| accentuating global warming and hastening the return to the interglacial climate. 3933,1994,3,2,CARBON SEQUESTRATION| BIOLOGICAL DIVERSITY| AND SUSTAINABLE DEVELOPMENT - INTEGRATED FOREST MANAGEMENT,Tropical deforestation provides a significant contribution to anthropogenic increases in atmospheric CO2 concentration that may lead to global warming. Forestation and other forest management options to sequester CO2 in the tropical latitudes may fail unless they address local economic| social| environmental| and political needs of people in the developing world. Forest management is discussed in terms of three objectives: carbon sequestration| sustainable development| and biodiversity conservation. An integrated forest management strategy of land-use planning is proposed to achieve these objectives and is centered around: preservation of primary forest| intensified use of nontimber resources| agroforestry| and selective use of plantation forestry. 3799,1994,4,3,CARBON-DIOXIDE - POLLUTANT OR POTENTIAL CHEMICAL FEEDSTOCK,This review provides a general introduction to carbon dioxide and its contribution to global warming| to the thermodynamics of CO2 reduction and to the electrocatalysis of this endogenic process. Contributions from the author's laboratories which provide firm evidence for the mechanism of the electrocatalytic reduction of CO| in the presence of protons are discussed. Advantages in the possible use of metal clusters and| in particular| metal clusters containing polypyridine ligands as potential electrocatalysts for this reduction process are outlined| and the synthesis| chemistry and electrocatalytic activity of some of the complexes of this type are highlighted. The second half of the review is devoted to discussion on the synthesis and coordination behaviour of custom-built phosphorus-polypyridine ligands such as 6-diphenylphosphino-2|2'-bipyridine (Ph(2)Pbpy) and 2-(diphenylphosphino)quinoline (Ph(2)Pquin)| ligands designed to curtail the fragmentation of dinuclear and metal cluster compounds as well as to function as electron reservoirs on the surface of the cluster| This is followed by discussion on the electrocatalysis of CO2 reduction by a number of dinuclear systems containing these ligands| such as [Cu-2(mu-Ph(2)Pbpy)(2)(MeCN)(2)](2+). Finally| reference is made to the carboxylation of unsaturated organic compounds promoted by electrogenerated catalysts and to the development of photo- and photoelectrocatalysts for CO2 reduction. 3945,1994,3,2,CFC-FREE RIGID POLYURETHANE FOAM INSULATION PRODUCTS,This paper provides an overview of the commercially successful CFC-free rigid polyurethane insulating products now established in the UK market| which have been made available because of the need to move away from the use of potent ozone depleting CFC blowing agents used for the past 35 years. Detailed evidence is included to support the claim that the performance of these new products and their life expectancy is equal to that of their CFC based counterparts. It shows that because of the great diversity of products and applications| that currently five different blowing agents are used since whilst many ozone benign blowing agents exist| none matches the other unique features of the CFCs R11 and R12 entirely. Nevertheless it is demonstrated that the products now in use in the UK| by comparison with their CFC counterparts| are playing a significant part in eliminating the threat to the ozone layer| whilst at the same time being able to continue to make their significant contribution to the reduction of CO2 emissions| believed to be the main cause of global warming. 3791,1994,2,3,CHLOROFLUOROCARBON UPTAKE IN A WORLD OCEAN MODEL .1. SENSITIVITY TO THE SURFACE GAS FORCING,The uptake and redistribution of chlorofluorocarbons (CFCs) CFC-11 and CFC-12 are studied in a series of world| ocean model experiments. In part 1 of this study the sensitivity of the simulated CFC distributions to the model parameterization of air-sea CFC fluxes is examined within a control experiment. The control experiment represents a low-resolution ocean model with global coverage and a proper seasonal cycling in surface thermohaline and wind stress conditions. The specification of a surface ocean CFC concentration that is instantaneously in saturated equilibrium with the atmosphere is found to flux too much CFC into the model. Signatures of CFC-11 are found to be grossly overestimated in regions of deep and bottom water formation| both in the surface mixed layer and at depth. The use of a classical air-sea gas exchange formula (even one with a simplified gas transfer velocity that is independent of wind speed) is seen to greatly improve the CFC simulations at depth. In addition| the model reproduces many of the observed trends in surface CFC concentrations; namely| undersaturation in regions of deep convective overturn and near-surface upwelling and supersaturation in the summer mixed layer. In further sensitivity experiments| we consider the effect of sea ice cover in limiting air-sea gas exchange in polar waters. It is found that bottom water in the Arctic Ocean and around the Antarctic continent is significantly reduced in CFC content once regions covered with sea ice are limited to fractional air-sea gas exchange. This more physically meaningful framework is found to further reduce the spurious uptake of CFC-11 and CFC-12 found under a ''saturated surface'' assumption. In a final sensitivity experiment the gas exchange rate is parameterized using a complete wind speed and Schmidt number dependence. The wind speed dependent gas forcing increases the surface CFC equilibration rate under the subpolar westerlies. On the other hand| the polar and tropical oceans witness reduced CFC uptake under a wind speed dependent flux regime. Simulated ocean CFC concentrations are compared directly with observational data in certain key areas for deep and bottom water formation. It is found that a reasonable representation of oceanic CFC is achieved in the convected water column in the Weddell and Labrador Seas. In contrast| deep waters that have left the convective area with the model ocean currents are found to be deficient in CFC-11 in the North Atlantic Ocean. This is because the model advective timescale for North Atlantic Deep Water (NADW) outflow across the equator is too long compared with observed ocean estimates. The long timescale is not due to unrealistically sluggish deep currents. Rather| the path of NADW outflow includes a loop eastward from the Labrador Sea into the Northeastern Atlantic Basin| effectively increasing the required outflow journey by around 4000 km. This ages the water mass by almost 10 years| thereby yielding significantly lower CFC concentrations in the NADW extension. In addition| the outflow signature spreads too far into the eastern North Atlantic| presumably because the advective process is too broad and the horizontal diffusion too strong at depth. Contrasting the North Atlantic| bottom water CFC ventilation in the Southern Ocean is found to be too strong| even when significant levels of surface undersaturation are simulated in polar waters. CFC-tagged waters flowing into the deep South Atlantic basin (from the Weddell Sea formation zone) are too enriched in CFC11| even when the deep signatures adjacent to the Antarctic shelf remain close to observations. This suggests that the advective timescale for bottom water ventilation is too rapid in the Southern Ocean. In addition| too much convective overturn persists in the Southern Ocean at 55 degrees S-70 degrees S| with unrealistically deep CFC-11 penetration noted at particular longitudes. This is because not enough older (CFC-deprived) water recirculates and upwells into the Southern Ocean. For example| more upwelled circumpolar deep water in the Southern Ocean would weaken the CFC-11 concentrations by contributing to a lower CFC mixture and by suppressing the convective activity in the region. Bottom and deep level CFC signatures are broad and diffuse compared with the real ocean. The broadness of the CFC imprint is due| in part| to the model resolution| which gives any convective event a spatial extent of at least 3.75 degrees longitude by 4.5 degrees latitude and a bottom level CFC signal thickness in excess of 800 m. An important finding of our study is that the vertical convection of unstable waters acts as the efficient tracer ventilator of the ocean system. This has significant implications for numerical studies of the world's climate| since the meridional overturning has traditionally been considered the reason for the ocean's moderating influence during global warming scenarios. Our study suggests that the vertical convection would play a much greater role over the typical timescale for anthropogenic climate change. 2638,1994,2,4,CLADODE DEVELOPMENT| ENVIRONMENTAL RESPONSES OF CO2 UPTAKE| AND PRODUCTIVITY FOR OPUNTIA-FICUS-INDICA UNDER ELEVATED CO2,Opuntia ficus-indica| an extremely productive CAM plant cultivated in many countries| was exposed to 36| 52| and 72-73 Pa CO| in field plots and open-top chambers. Initiation of new cladodes (stem segments) was monitored until the canopy closed| after which bimonthly harvests maintained the plants for one year at a cladode area per unit ground area that is optimal for biomass production. Doubling the CO2 partial pressure slightly increased the number of first-order daughter cladodes growing on the basal (planted) cladodes after 3 months and nearly doubled the number and area of second-order cladodes. When the CO2 level was doubled| cladodes were 5% thicker after a few months and 11 to 16% thicker after one year. Although the productivity enhancement by elevated CO2 tended to decrease during the year| the annual above-ground dry-mass gain was 37 to 40% higher when the CO2 level was doubled| reaching 65 tons hectare(-1) year-l in a field plot. Well-watered cladodes at day/night air temperatures of 25 degrees C/15 degrees C and a total daily photosynthetic photon flux (PPF) of 15 mol m(-2) d(-1) in controlled environment chambers had 74% more net CO2 uptake over 24 h at 73 Pa than at 37 Pa CO2. With doubled CO2| the percentage enhancement of net CO2 uptake increased as the PPF was lowered| as the temperature was raised| and during drought. Using an environmental productivity index based on such factors| net CO2 uptake and hence productivity of O. ficus-indica can be predicted for elevated CO2 levels and other variations accompanying global climate change.
2616,1994,2,4,CLIMATE AND THE SOUTHERN LIMIT OF THE WESTERN CANADIAN BOREAL FOREST,Four species of boreal forest conifers share a similar southern limit of natural distribution in the three Prairie Provinces of western Canada. The southern boundaries of boreal forest and aspen parkland were compared with geographic patterns of several climate variables to provide a preliminary assessment of how global climate change could affect forest distribution in the future. Forest zonation corresponded most closely with climatic moisture regimes (annual precipitation minus potential evaporation). In contrast| thermal characteristics of climate (mean July and annual temperature| growing degree-days) showed an inconsistent relationship with forest zonation. It is postulated that moisture limitations prevent conifer regeneration south of the present limit of natural distribution. Alternatively| the more arid climates south of the boreal forest may have promoted higher fire frequencies historically| thus preventing conifers from achieving sufficient longevity to regenerate. The driest areas of boreal forest in the region occur at low elevations in west-central Manitoba| throughout Saskatchewan and Alberta| and the southwestern Mackenzie District| Northwest Territories; these areas may be most vulnerable to increased climatic dryness. Climatically induced losses of forest cover from these low-elevation areas could eventually lead to the fragmentation of the boreal forest in western Canada.
3797,1994,2,2,CLIMATE OF THE 21ST-CENTURY,The outgoing long wave radiation to space is significantly reduced as a result of heat absorption by the so-called greenhouse gases| notably water vapour| carbon dioxide| methane| nitrous oxides and chlorofluorocarbons. The dominating ones are water vapour and carbon dioxide. The direct effect of the greenhouse gases is to increase the average temperature of the earth's surface by some 33 degrees C| that is from -18 degrees C to the present 115 degrees C. Since the industrial revolution the combustion of fossil fuels and deforestation has led to an increase of 26% in carbon dioxide in the atmosphere. It is presently increasing by about 0.5% per year. Based on strict radiative forcing calculations| the total additional warming because of the increase in greenhouse gases| not including the effect of associated changes in water vapour| is equivalent to about 2.5 W m(-2) and is estimated to increase to some 10 W m(-2) at the end of the next century. The solar constant| by comparison| is equal to 341 W m(-2) globally averaged. The effect on climate cannot satisfactorily be estimated on radiation balance calculation only but must incorporate the large scale atmospheric circulation and the important feedbacks with water vapour (positive feedback)| clouds (both positive and negative feedbacks)| surface albedo and the oceans. For that reason it is necessary to build comprehensive mathematical models of the coupled ocean/land atmosphere system and carry out numerical simulation experiments. Several such studies have been undertaken during the last few years both in Europe and the USA. Results from these experiments| and in particular from those carried out at the Max-Planck-Institut fur Meteorologie in Hamburg| will be presented and discussed. Because of the enormous complexity of the problem| a number of simplified assumptions have been used and the results so far must be cautiously assessed. The overall global warming from these experiments is about 3 degrees C with a difference of about 0.5 degrees C between the experiments. There are large regional differences and the warming is generally larger over land than over sea. A particular problem is the temperature of the North Atlantic and also in the Antarctic waters where changes in the deep ocean circulation are significant. The strong coupling to the deep ocean circulation in the North Atlantic reduces the warming in this area and consequently moderates the effect on the European climate. Sea level is estimated to increase by around 15 cm because of thermal expansion of sea water; however| it appears likely that there may also be an increased accumulation of ice on Antarctica and probably Greenland which may at least partly compensate for this increase. Possible changes in the vegetation following a climate change have been estimated by evaluating the response of a biome model. This shows minor changes in the vegetation; over Europe and North America a small north-eastward movement of the Vegetation zones. 3864,1994,4,4,CLIMATE VARIATION AND EL-NINO SOUTHERN OSCILLATION EVENTS ON THE GREAT-BARRIER-REEF - 1958 TO 1987,Seasonal and inter-annual variation of several surface climate variables near the Great Barrier Reef (GBR) are described for the 30-year period| 1958-1987. Large inter-annual variability of rainfall and river flow in coastal Queensland is linked to the aperiodic influences of El Nino-Southern Oscillation events. These events also affect sea surface temperature and wind fields| though the inter-annual variability of these variables is not as large as rainfall and river flow. The major impacts on waters of the GBR appear to be greatly increased freshwater inputs| reduced surface radiation (and thus light levels) and enhanced tropical cyclone activity during anti-El Nino events. El Nino events have less effect on climate of the GBR because they tend to maintain winter-like conditions. The effects of this background of high variability in the physical environment on reef processes must be considered when examining changes in such processes| changes in climate (e.g. due to global warming) or increases in anthropogenic impacts. 3944,1994,2,4,CLIMATE-CHANGE AND ALTERED RUNOFF IN THE SEMIARID PORTION OF MONO BASIN| CALIFORNIA,Mono Basin is a closed hydrologic unit and is highly sensitive to anticipated changes in temperature and precipitation related to global warming. Available water in the basin is limited and intensely managed. Cottonwood Creek and Bridgeport Creek drain the northern non-Sierra portion of the Mono Basin| and while these watersheds contribute relatively little of the total runoff into Mono Lake| their hydroclimatic conditions are representative of the majority of the Mono Basin drainage area. The hydrologic balance for these watersheds is modeled and selected climate change scenarios are simulated to determine the magnitude of change in water surplus resulting from altered temperature of +/-1-degrees and +/-2-degrees-C and precipitation changes of +/-10% and +/-20%. Changes in modeled water surplus expressed as a percentage of existing conditions range between 154% and 35% for Cottonwood Creek and 174% and 20% for Bridgeport Creek. Both watersheds display a greater response to a given change in precipitation than to a change in temperature. Bridgeport Creek is more sensitive than Cottonwood Creek to both precipitation and temperature change| owing to its more arid baseline conditions and lower elevation. 2631,1994,3,3,CLIMATE-CHANGE IMPLICATIONS FOR EUROPE - AN APPLICATION OF THE ESCAPE MODEL,Policy makers| charged both with identifying Possible national response strategies to climate change and with negotiating international conventions and protocols| need tools which enable them to estimate the implications for climate change of a wide range of policY options and which summarize the uncertainties surrounding global climate change. One such tool| recently constructed for the Environment Directorate of the Commission of the European Communities|1 consists of an interactive climate change impact assessment model called ESCAPE. This paper describes the model framework and illustrates the use of ESCAPE using a range of input scenarios reflecting different global policy| economic and technological futures. Three important characteristics of the global climate change problem are well illustrated: past emissions of greenhouse gases and the inertia of the global development path have committed the world to future warming irrespective of current and near-future policy interventions; the efficacy of a climate Policy implemented solely within the EC on altering the course of future climate change is very small; and the impacts of climate change on the economy and environment of the European Community differ markedly between northern and southern Europe.
3827,1994,2,3,CLIMATE-CHANGE| POTENTIAL EVAPOTRANSPIRATION AND MOISTURE AVAILABILITY IN THE MEDITERRANEAN BASIN,Simple methods for estimating potential evapotranspiration| requiring only temperature and day length data| are compared by reference to the results from the Penman method. A modification of the Blaney and Criddle method| in which the c parameter is calculated from seasonal regression equations with the mean monthly temperature as the independent variable| is proposed and tested. It is found to work sufficiently well in the area of interest| the Mediterranean Basin. For a network of 248 Mediterranean temperature stations| present-day seasonal mean potential evapotranspiration is estimated by this method. Using the results from four equilibrium-mode general circulation models| seasonal mean scenarios of potential evapotranspiration per 1-degree-C rise in global mean temperature caused by the enhanced greenhouse effect are presented. Comparison of scenarios of the change in potential evapotranspiration and scenarios of the change in precipitation indicates an unfavourable shift in moisture availability due to the enhanced greenhouse effect| throughout the Mediterranean region. 2610,1994,2,4,CLIMATE-INDUCED ANNUAL VARIATION IN CANOPY TREE GROWTH IN A COSTA-RICAN TROPICAL RAIN-FOREST,1 Annual growth was measured over eight consecutive years (1984-92) for saplings and adults of a diverse group of nonpioneer tree species in a lowland neotropical rain forest (La Selva Biological Station| Costa Rica). The study species included five emergents and one canopy species. 2 Adult diameter increments varied markedly from year to year for all species. In the year of highest growth for individual species| mean increments were 25-112% greater than in the year of least growth. These among-year differences were significant for five of the six species. 3 The variation in adult growth rates showed strong temporal concordance across species. For all six species| mean adult diameter increments were higher than average in 1985 and were lower than average in 1986 and 1988. 4 Marked year to year growth differences were also shown by juvenile trees of these species. In the class greater than or equal to 50 cm tall and less than or equal to 1 cm in diameter| mean diameter increments were 3-10 times greater in the year of highest growth than in the year of least growth. In each of the other two juvenile size classes (1-10 cm and 10-30 cm in diameter)| two species showed highly significant among-year growth variation. 5 Within all three juvenile size classes| the year to year growth variation showed significant temporal concordance across species. As for adults| 1985 and/or 1984 were among the two highest growth years. 6 That these patterns of interyear growth differences were shared across tree species and between saplings and adults demonstrates significant impacts of climatic variability on the productivity of this 'equable' ecosystem. 7 Annual rainfall was not correlated with the annual growth patterns. Although the two years of highest overall growth| 1984 and 1985| were exceptionally dry| adult trees of two species showed their greatest growth in one of the highest rainfall years (1990). 8 Recent studies suggest that photosynthetically active radiation (PAR) controls productivity of tropical wet forests. Recent data from La Selva show strong year to year variation in monthly PAR. Demonstration of a causal relationship will| however| require concurrent measurement of tree growth| PAR| and other climatic factors. 9 Marked temporal variation in tree growth in tropical wet forests will have pervasive consequences for many processes in these complex ecosystems. Moreover| the degree of climatic sensitivity found in this study indicates that tropical rain forests could be strongly affected by global climate change.
3833,1994,2,4,COASTAL STRUCTURES| WASTE MATERIALS AND FISHERY ENHANCEMENT,Current U.K. practice relating to the disposal of material at sea is reviewed. The use of stabilization technology relating to bulk waste materials| coal ash| oil ash and incinerator ash is discussed. The extension of this technology to inert minestone waste and tailings| contaminated dredged sediments and phosphogypsum is explored. Uses of stabilized wastes are considered in the areas of habitat restoration| coastal defense and fishery enhancement. It is suggested that rehabilitation of marine dump sites receiving loose waste such as pulverized fuel ash (PFA) could be enhanced by the continued dumping of the material but in a stabilized block form| so creating new habitat diversity. Global warming predictions include sea level rise and increased storm frequency. This is of particular concern along the southern and eastern coasts of the U.K. The emphasis of coastal defenses is changing from ''hard'' seawalls to ''soft'' options which include offshore barriers to reduce wave energy reaching the coast. Stabilized waste materials could be included in these and other marine constructions with possible economic benefit. Ministry of Agriculture| Fisheries and Food (MAFF)| the regulatory authority in England and Wales for marine disposal/construction| policy regarding marine structures and fishery enhancement is outlined. A case is made for the inclusion of fishery enhancement features in future coastal structures. Examples of the productivity of man-made structures are given. Slight modification of planned structures and inclusion of suitable habitat niches could allow for the cultivation of kelp| molluscs| crustacea and fish. 3798,1994,3,3,COMPUTER-SIMULATION OF A NOVEL CIRCULATING FLUIDIZED-BED PRESSURE-TEMPERATURE SWING ADSORBER FOR RECOVERING CARBON-DIOXIDE FROM FLUE-GASES,Carbon dioxide (CO2) is considered to be the major greenhouse gas contributing to global warming. While reducing fossil fuel consumption may provide the ultimate answer to CO2 emission problems| one of the short-term solutions is the separation and subsequent disposal of the CO2 from power plant and industrial flue gas streams. A novel| energy-efficient CO2 separation process known as the circulating fluidized bed pressure-temperature swing adsorber (CFB-PTSA) is simulated in this work. A hydrodynamic model for the gas and solids flow structure in the riser of circulating fluidized beds is combined with a competitive adsorption model for a carbon dioxide| nitrogen| oxygen mixture on a type X zeolite| as described by the ideal adsorbed solution theory| to predict the reactor performance. Simulations performed at various riser operating conditions and flue gas CO2 concentrations indicate that the CO2 recovery decreases with increasing concentration at a fixed solids circulation Bur| but the purity of the recovered product increases. Recoveries in the range of 65-88.5% and product purities of 75-90% CO2 are predicted. 3869,1994,3,3,CONTROLLING SUBSTANCE FLOWS - THE CASE OF CHLORINE,The contribution of chlorinated hydrocarbons (CHCs) to environmental problems in the Netherlands is discussed in an economic context. The economic interactions within the chlorine market| including the link to caustic soda production| are described| and PVC is taken as a case study. Key policy options are evaluated in terms of their potential for environmental improvement. It appears that 95% of CHC emissions causing environmental problems are due to dissipative applications. With respect to the specific problems of ozone depletion and global warming| only a small group of compounds is responsible for most of the impact. Moreover| economic interactions within the group of CHCs can strongly influence the net effect of environmental policy measures. Policies aimed at a reducing volume output of certain specific groups of CHCs will inevitably lead to trade-offs between environmental problems. The environmental impact of a hypothetical ban on CHCs is discussed in relation to the use of PVC as a sink for chlorine. Both these options appear to have drawbacks. Moreover| no absolute conclusion can be drawn until the environmental impact of CHC substitutes is known. 2652,1994,2,2,CORE AND PERIPHERAL-POPULATIONS AND GLOBAL CLIMATE-CHANGE,Environmental conditions outside the periphery of a species' distribution prevent population persistence| hence peripheral populations live under conditions different from those of core populations. Peripheral areas are characterized by variable and unstable conditions| relative to core areas. Peripheral populations are expected to be genetically more variable| since the variable conditions induce fluctuating selection| which maintains high genetic diversity. Alternatively| due to marginal ecological conditions at the periphery| populations there are small and isolated; the within-population diversity is low| but the between-population genetic diversity is high due to genetic drift. It is also likely that peripheral populations evolve resistance to extreme conditions. Thus| peripheral populations rather than core ones may be resistant to environmental extremes and changes| such as global climate change induced by the anthropogenically emitted ''greenhouse gases''. They should be treated as a biogenetic resource used for rehabilitation and restoration of damaged ecosystems. Climatic transition zones are characterized by a high incidence of species represented by peripheral populations| and therefore should be conserved now as repositories of these resources| to be used in the future for mitigating undesirable effects of global climate change. Preliminary research revealed high phenotypic variability and high genetic diversity in peripheral populations relative to core populations of wild barley and the chukar partridge| respectively.
3832,1994,2,4,COTTON EVAPOTRANSPIRATION UNDER FIELD CONDITIONS WITH CO2 ENRICHMENT AND VARIABLE SOIL-MOISTURE REGIMES,The CO2 concentration of the atmosphere is predicted to double by the next century| and this is expected to increase significantly the growth and yield of many important agricultural crops. One consequence of larger and more vigorous plants may be increased crop evapotranspiration (ET) and irrigation water requirements. The objective of this work was to determine ET of cotton (Gossypium hirsutum L. cv. 'Deltapine 77') grown under ambient (about 370 mumol mol-1) and enriched (550 mumol mol-1) CO2 concentrations for both well-watered and water-stress irrigation managements. Studies were conducted in 1990 and 1991 within a large| drip-irrigated cotton field in central Arizona. Cotton ET was measured during the growing seasons using a soil water balance| based on neutron gauge soil water measurements. ET| for periods from 7 to 14 days| was not significantly different between ambient and enriched CO2 treatments at the 0.05 probability level| and the total seasonal ET for the CO2 treatments varied by 2% or less in either year. However| water-stress treatments| which were initiated on 3 July (day of year (DOY) 184) in 1990 and on 20 May (DOY 128) in 1991| had significantly lower (P < 0.05) ET than well-watered treatments starting at the end of July in 1990 and in early July in 1991 when the plants were about 75-90 days old. The result that CO2 enrichment to 550 mumol mol-1 did not significantly change the ET of cotton was consistent with the results of co-investigators who measured ET in the same experiments using stem flow gauges and an energy balance. This result implies that irrigation water use would not have to be increased to produce cotton in a future high-CO2 world. However| if a concomitant change in climate occurs| such as global warming| cotton evapotranspiration may change in response to the changed weather condition. 3860,1994,2,4,CURRENT CHANGES OF CLIMATE AND PERMAFROST IN THE ARCTIC AND SUB-ARCTIC OF RUSSIA,In northern Russia| from the time meteorological measurements began in the early nineteenth century to the end of that century| the air temperature was characterized by a general decrease (approximately 1 degrees C). It then rose up to the 1950s (by 0.6 degrees C). A subsequent slight fall in temperature lasted until the mid 1970s. Since then a further rise has been observed (0.6-0.9 degrees C). Temperatures in the upper horizons of permafrost over the last 10-20 years are in good agreement with recent global warming trends. For the European north-east during the period 1970-90 a rise in temperature at a depth of 3 m amounted to 0.6-0.7 degrees C on average. However| this rise is related not necessarily to a rise in air temperature| but more likely to an increase in snow cover. 3903,1994,4,4,DECADAL ATMOSPHERE-OCEAN VARIATIONS IN THE PACIFIC,Considerable evidence has emerged of a substantial decade-long change in the north Pacific atmosphere and ocean lasting from about 1976 to 1988. Observed significant changes in the atmospheric circulation throughout the troposphere revealed a deeper and eastward shifted Aleutian low pressure system in the winter half year which advected warmer and moister air along the west coast of North America and into Alaska and colder air over the north Pacific. Consequently| there were increases in temperatures and sea surface temperatures (SSTs) along the west coast of North America and Alaska but decreases in SSTs over the central north Pacific| as well as changes in coastal rainfall and streamflow| and decreases in sea ice in the Bering Sea. Associated changes occurred in the surface wind stress| and| by inference| in the Sverdrup transport in the north Pacific Ocean. Changes in the monthly mean flow were accompanied by a southward shift in the storm tracks and associated synoptic eddy activity and in the surface ocean sensible and latent heat fluxes. In addition to the changes in the physical environment| the deeper Aleutian low increased the nutrient supply as seen through increases in total chlorophyll in the water column| phytoplankton and zooplankton. These changes| along with the altered ocean currents and temperatures| changed the migration patterns and increased the stock of many fish species. A north Pacific (NP) index is defined to measure the decadal variations| and the temporal variability of the index is explored on daily| annual| interannual and decadal time scales. The dominant atmosphere-ocean relation in the north Pacific is one where atmospheric changes lead SSTs by one to two months. However| strong ties are revealed with events in the tropical Pacific| with changes in tropical Pacific SSFs leading SSTs in the north Pacific by three months. Changes in the storm tracks in the north Pacific help to reinforce and maintain the anomalous circulation in the upper troposphere. A hypothesis is put forward outlining the tropical and extratropical realtionships which stresses the role of tropical forcing but with important feedbacks in the extratropics that serve to emphasize the decadal relative to interannual time scales. The Pacific decadal timescale variations are linked to recent changes in the frequency and intensity of El Nino versus La Nina events but whether climate change associated with ''global warming'' is a factor is an open question. 3917,1994,3,3,DESIGN AND CONSTRUCTION OF A SOLAR-ELECTRIC VEHICLE,Recent concerns relating to global warming caused by greenhouse gases| coupled with a growing awareness of the limited available resources of fossil fuels| have spurred an interest in alternative energy powered vehicles. This paper describes the analysis| development| and testing of an aerodynamic vehicle powered by photovoltaic cells. The primary components of the vehicle are the composite material body| the aluminum space frame| the wheel hubs and front suspension assembly| the drive train and the electrical system. The frame was designed using finite element analysis with the components of the frame modeled as beam elements. The body| designed to have a very high strength-to- weight ratio| was of graphite/Kevlar/Nomex sandwich construction. Testing was carried out using the three-point bend test to determine the optimal sandwich cross-sectional configuration. The design of the front suspension| the wheel hubs| and the power transmission are also discussed. The electrical system| based on a monocrystalline photovoltaic cell assembly| and silver-zinc storage cells| is also described. Finally| results of the optimization routine developed are also described. 3918,1994,4,2,DETECTING CLIMATIC-CHANGE SIGNALS - ARE THERE ANY FINGERPRINTS,Projected changes in the Earth's climate can be driven from a combined set of forcing factors consisting of regionally heterogeneous anthropogenic and natural aerosols and land use changes| as well as global-scale influences from solar variability and transient increases in human-produced greenhouse gases. Thus| validation of climate model projections that are driven only by increases in greenhouse gases can be inconsistent when one attempts the validation by looking for a regional or time-evolving ''fingerprint'' of such projected changes in real climatic data. Until climate models are driven by time-evolving| combined| multiple| and heterogeneous forcing factors| the best global climatic change ''fingerprint'' will probably remain a many-decades average of hemispheric-to global-scale trends in surface air temperatures. Century-long global warming (or cooling) trends of 0.5-degrees-C appear to have occurred infrequently over the past several thousand years-perhaps only once or twice a millennium| as proxy records suggest. This implies an 80 to 90 percent heuristic likelihood that the 20th-century 0.5 +/- 0.2-degrees-C warming trend is not a wholly natural climatic fluctuation. 3819,1994,4,3,DETERMINATION OF NITROUS-OXIDE IN SOIL,Nitrous oxide is one of the greenhouse gases which together with carbon dioxide| methane and chlorofluorocarbons has an influence on global warming. The average increase of atmospheric nitrous oxide has been estimated at about 0.2 similar to 0.3% per year. It is impotant| therefore| that sources and emission rates of nitrous oxide are investigated all over the world. In this work| the nitrous oxide concentration in the soil at 80 cm in depth at 30 sites was investigated in the Tokyo metropolitan area. As a result| it was found that the concentration of nitrous oxide was higher in the soil air than in the atmosphere for all of the sampling sites. 3818,1994,3,4,DETERMINATION OF THE INFRARED CROSS-SECTIONS AND GLOBAL WARMING POTENTIALS OF 1|1|2-TRIFLUOROETHANE (HFC-143),The Global Warming Potentials (GWPs) of CH2F-CHF2 (HFC-143) have been estimated for different time horizons. Radiative forcings associated with this CFC alternative have been derived relative to CFC-11 and CO2 by introducing laboratory measured absorption cross sections into a coupled chemical-radiative model. 3909,1994,3,4,DEVELOPMENT OF A HIGH-EFFICIENCY DOMESTIC REFRIGERATOR USING CFC SUBSTITUTES,Besides the values of the ozone depletion and global warming potentials| energy consumption is another important index to be considered in developing a refrigeration system using CFC substitutes. Many investigators have indicated that unless the original refrigeration system is correspondingly adjusted when using CFC substitutes| the energy efficiency ratio (EER) of the system will decrease. In this paper| the reasons for a decrease in EER are analysed theoretically| and some proposals for increasing EER are put forward. These proposals are used to develop a domestic refrigerator charged with a non-azeotropic mixture of HCFC22/HFC152a as the substitute for the original working fluid| CFC 1 2. The results show that the EER value of the refrigerator charged with this refrigerant mixture is increased by 6.5% compared with that of the same refrigerator charged with CFC12. 2648,1994,2,4,DISSOLVED-OXYGEN MODEL FOR REGIONAL LAKE ANALYSIS,A deterministic| one-dimensional| unsteady dissolved oxygen (D.O.) model has been formulated to simulate summer D.O. conditions (stratification) in a wide range of lakes of the north central United States and to study potential impacts of global climate change. The simulation includes contributions by photosynthesis| plant respiration| reaeration| biochemical oxygen demand (BOD) and sedimentary oxygen demand (SOD) as source and sink terms. The one-dimensional vertical oxygen transport equation is solved in conjunction with the heat transport equation in daily time steps beginning 1 March and ending 31 October. Lake morphometry| trophic status and daily weather parameters have to be specified as input| and daily profiles of water temperature and dissolved oxygen are obtained as output. The model finds the onset of summer-stratification from initially isothermal and constant D.O. conditions. Trophic status is related to Secchi depth| phytoplankton (chlorophyll-alpha) concentrations| BOD and SOD. Field data from seven lakes (11 years) have been used to calibrate and validate the D.O. model. The simulations for dimictic lakes with strong stratification are better than for weakly stratified polymictic lakes| i.e. the model works better for deep lakes than for shallow lakes. The average standard errors for calibration and validation are 1.4 and 1.9 mg D.O. l(-1)| respectively. The temperature simulations| especially the mixed-layer depth| affect the D.O. simulation results. A sensitivity analysis to model coefficients was also conducted. The model is most sensitive to sedimentary oxygen demand (SOD). Twenty seven classes of lakes (3 depths X 3 areas X 3 trophic states) in the north central U.S. were analyzed with the model. Simulated mean daily dissolved oxygen concentrations in the epilimnion are near saturation| those in the hypolimnion vary considerably depending particularly on length of time since the onset of stratification and the sedimentary oxygen demand.
2639,1994,3,4,DISTRIBUTING COSTS OF GLOBAL CLIMATE-CHANGE,The problem of global climate change links the issues of energy utilization| economic development| environmental degradation| and equity on a planetary scale. Questions concerning the scale and timing of the impact of continuously increasing emissions of greenhouse gases remain. A set of approaches has emerged which claim to objectively demonstrate that nothing or very little should be done to address this problem. These approaches rely on standard economic theory and analytical methods to reach their conclusion that significant worldwide action is unnecessary. In the authors' view| however| these approaches contain biases which place an exceptionally high value on maintaining the status quo of global patterns of resource consumption and distribution of wealth. When utilized to analyze various policy options| this bias results in a determination that equity considerations are too costly and may impede technological and economic progress. As an alternative| the authors propose an approach based on a principle of equity in atmospheric resource utilization
3881,1994,2,4,DISTRIBUTION AND ECOLOGY OF CIGUATERA FISH POISONING IN FLORIDA| WITH EMPHASIS ON THE FLORIDA-KEYS,Ciguatera fish poisoning is a disease causing human health problems for persons eating fishes from tropical seas or for extra-tropical residents who have eaten fishes imported from tropical seas. Of the estimated 1|300 cases of ciguatera in south Florida| probably 10% are from fishes caught in south Florida waters; the rest are purchased from restaurants or seafood markets in south Florida who sell fish species which are potentially ciguatoxic. Many fish species are misidentified by restaurateurs or are from non-Florida sources| especially the Bahamas. This paper documents the (a) species| (b) locations| and (c) size of fishes which have caused ciguatera intoxications in the Florida Keys| as well as other locations along the Florida east coast. Evidence is presented from other tropical areas that (1) increases in sea surface temperature from global warming| (2) eutrophication from human activities| and (3) anthropogenic alterations such as dredging| filling| and coral reef destruction may increase the incidence of ciguatera in the future in the Florida Keys and elsewhere. 3809,1994,2,4,DO ROSS RIVER AND DENGUE VIRUSES POSE A THREAT TO NEW-ZEALAND,Aim. To determine the prevalence of antibodies to Ross River and dengue viruses in sera from New Zealand residents and travellers and to assess the potential of local mosquitoes to act as vectors of these viruses. Method. Serum specimens from several population groups were examined by haemagglutination-inhibition and neutralisation tests for antibodies to Ross River and dengue viruses between 1975 and 1993. During this period dengue was active in South East Asia| Australia and the Pacific| and a major epidemic of Ross River infection occurred in the Pacific. Two New Zealand mosquito species were tested for their ability to transmit by bite after they had been fed or injected with these viruses. Results. Ten percent of 1869 sera from patients suspected of contracting dengue| and 43% of 183 patients suspected of contracting Ross River virus| while overseas| were antibody positive. Many patients showed antibody rises which indicated that they were probably viraemic on entry to this country. Dengue viruses were isolated in Dunedin from two patients with dengue haemorrhagic fever contracted overseas. Antibody studies of persons who had not travelled outside New Zealand provided no evidence of local transmission of these viruses. Two local mosquitoes| Aedes notoscriptus from the Auckland area| and Aedes australis from the Otago area| were able to transmit one or both these viruses under laboratory conditions. Conclusions. The serological studies showed that both Ross River and dengue viruses have probably been introduced into New Zealand by viraemic travellers on many occasions. Although some local mosquitoes can transmit these viruses in the laboratory| there is no evidence of local spread of virus from these imported cases. Changing environmental conditions such as global warming with concomitant effects on vector distribution| increasingly rapid air travel by viraemic persons and the accidental introduction of new vector mosquitoes| particularly Aedes albopictus| could pose a threat in view of the high percentage of New Zealand residents with no protective antibody. 2623,1994,2,3,EARLY SELECTION OF BLACK SPRUCE SEEDLINGS AND GLOBAL CHANGE - WHICH GENOTYPES SHOULD WE FAVOR,We investigated the effects of both soil fertility and predicted changes in climate on the performance of different families of black spruce| Picea mariana (Mill.) B.S.P.| during the first growing season. The results were used to examine whether reforestation programs should consider changing their preferred family lines in anticipation of altered performance given global climate change. We grew seedlings of 16 open-pollinated maternal families of black spruce under phytotron conditions simulating present and mid-21 st century climatic conditions during the growing season. The realistic| simulated future climate included both elevated CO2 levels and seasonally appropriate increases in mean daily temperature. To explore the dependence of climatic responses on site quality| seedlings were irrigated with solutions having either 5 or 100 mg/L of nitrogen. The lower nitrogen level represents a poor site for black spruce growth and survival| but the higher level provides ample nitrogen. We also recorded seed size for each seedling to evaluate the degree to which maternal investments might buffer responses to future climate and fertility during the first year on the seedbed. Seedling survival and growth increased both under the future climate regime and with nitrogen fertilization. The two factors interacted synergistically| with nitrogen enrichment significantly enhancing the positive effects of the future climate regime. Nitrogen-poor conditions| however| did not preclude a positive seedling response to the future climate. Our results indicate that seedling survival and height growth are highly dependent upon initial seed mass: larger seeds produced more vigorous 1 st-yr seedlings. The families differed in seed mass| seed germination| and seedling survival and growth| but their relative performances did not vary significantly among the treatments. These results suggest that black spruce families selected for rapid growth under present conditions will also do well in the future| at least in terms of early establishment and performance on sites regenerated by seeding.
2627,1994,2,4,ECOLOGICAL INDICATORS OF GLOBAL CLIMATE-CHANGE - A RESEARCH FRAMEWORK,Large-scale environmental research efforts are conducted under frameworks that provide a common basis for evaluating research in many diverse fields. Such frameworks should be subjected to critical review to determine if they meet crucial expectations. In the case of the US Global Change Research Program. we perceive that most research follows a framework that we define as the predictive model framework. We believe this framework is insufficient for resolving the unprecedented predicaments posed by global change. We recommend a complementary framework| the system response framework| which directs research toward useful indicators of change rather than precise predictions. We further argue that| even if research is complementary and effective under the two frameworks| conclusive results prior to decisions should not be expected. The burden of proof must itself be a continuing topic of open discourse and inquiry.
3942,1994,4,3,ECONOMIC GLOBAL WARMING POTENTIALS,A reformulation of global warming potentials is propounded| that combines the time-horizon and discounting definitions| and covers both ordinary atmospheric forcing (via greenhouse gases) and its rate-of-change. Insofar as GWPs are used to guide investment and socioeconomic choices| there is merit in adopting cost-benefit techniques. The parametric equivalence of the two definitions applies for the ordinary atmospheric forcing; but for its rat-of-change| only the discounting definition gives realistic results| as shown in application to methane| a short-lived greenhouse gas. 3872,1994,4,4,EDGE-DETECTION ALGORITHMS FOR 2-DIMENSIONAL ECOLOGICAL DATA,The widely advocated statement that ecotone movement may be useful in studies of the impacts of global warming implies not only that ecotones exist but that they can be delineated spatially. With sampled field data| the accuracy of the detected ecotone is related to the data type and its spatiotemporal resolution. In the present study| I introduce two edge detection algorithms for regularly (lattice-wombling) and irregularly (triangulation-wombling) two-dimensional sampled data. I investigate the reliability of these algorithms in detecting potential ecotones using simulated vegetation data that follow the individualistic| continuum-gradient| and community-type patterns. Ecotones were defined quantitatively as long narrow regions of high rates of change. Under this definition| significant ecotones were found mostly in the community-type patterns using either of the edge detection algorithms (lattice-wombling or triangulation-wombling) and a systematic or random sampling design| respectively. 3804,1994,2,4,EFFECT OF ELEVATED-TEMPERATURES ON CARBON-DIOXIDE EXCHANGE IN PICEA-RUBENS,We examined some of the physiological reasons that may underlie past and expected future migrations of red spruce (Picea rubens Sarg.) by evaluating the effects of high temperatures on photosynthesis and respiration of trees growing on Whiteface Mountain| NY. At temperatures of 35-40-degrees-C| the trees exhibited a zero or negative carbon balance. Higher temperatures resulted in cellular disorganization and death. Temperatures around 30-degrees-C resulted in reduced CO2 uptake| a condition that could decrease future reproductive output and competitive stature. We conclude that thermal intolerance explains| at least in part| the absence of red spruce at low elevations and latitudes where temperatures of greater-than-or-equal-to 30-degrees-C occur. We suggest that the thermosensitivity of this species is important with respect to global climate trends and migration patterns. 3902,1994,2,3,EFFECT OF GLOBAL WARMING ON INDIAN MONSOON SIMULATED WITH A COUPLED OCEAN-ATMOSPHERE GENERAL-CIRCULATION MODEL,The impact of increasing greenhouse gas concentrations on the climate of Indian subcontinent and its variability is studied using the output from a time-dependent greenhouse warming simulation as well as a reference control experiment performed with the Hamburg global coupled atmosphere-ocean circulation model. This model demonstrates substantial skill in simulating the present-day climate and its interannual variability over the monsoon onset date of the SW-monsoon over about 20 degrees N inferred from the control run is similar to the observed onset date. With the exception of temperature| the projected changes in impact-related climatic variables over a period of 100 years are within the range of inter-annual variability in the monsoon region. There is no clear evidence for a significant change in the seasonal-mean monsoon rainfall or the variability of the monsoon rainfall in scenario A experiment. region. The India along 3862,1994,2,4,EFFECTS OF CLIMATE-CHANGE ON COMMERCIAL BUILDING ENERGY DEMAND,Most of the studies of the impact of global warming on energy use have employed aggregated utility models and have found that global warming would produce about a 2% decrease in heating requirements per 1-degrees-C and comparable increases in cooling requirements. The one significant exception is a German study that utilized building energy models and determined that the increase in cooling would be somewhat larger| due to the effects of increased humidity with atmospheric warming. This study utilizes the DOE2 building energy model on a prototype commercial building and demonstrates that increased humidity could be a significant factor in total building energy use| particularly in the more humid parts of the United States. The study also demonstrates that the effect can be overcome with advanced building designs. 2629,1994,2,4,EFFECTS OF CO(2) ENRICHMENT ON WHOLE-PLANT CARBON BUDGET OF SEEDLINGS OF FAGUS-GRANDIFOLIA AND ACER-SACCHARUM IN LOW IRRADIANCE,Carbon exchange rates (CER) and whole-plant carbon balances of beech (Fagus grandifolia) and sugar maple (Acer saccharum) were compared for seedlings grown under low irradiance to determine the effects of atmospheric CO2 enrichment on shade-tolerant seedlings of co-dominant species. Under contemporary atmospheric CO2| photosynthetic rate per unit mass of beech was lower than for sugar maple| and atmospheric CO2 enrichment enhanced photosynthesis for beech only. Aboveground respiration per unit mass decreased with CO2 enrichment for both species while root respiration per unit mass decreased for sugar maple only. Under contemporary atmospheric CO2| beech had lower C uptake per plant than sugar maple| while C losses per plant to nocturnal aboveground and root respiration were similar for both species. Under elevated CO2| C uptake per plant was similar for both species| indicating a significant relative increase in whole-seedling CER with CO2 enrich ment for beech but not for sugar maple. Total C loss per plant to aboveground respiration was decreased for beech only because increase in sugar maple leaf mass counterbalanced a reduction in respiration rates. Carbon loss to root respiration per plant was not changed by CO2 enrichment for either species. However| changes in maintenance respiration cost and nitrogen level suggest changes in tissue composition with elevated CO2. Beech had a greater net daily C gain with CO2 enrichment than did sugar maple in contrast to a lower one under contemporary CO2. Elevated CO2 preferentially enhances the net C balance of beech by increasing photosynthesis and reducing respiration cost. In all cases| the greatest C lost was by roots| indicating the importance of belowground biomass in net C gain. Relative growth rate estimated from biomass accumulation was not affected by CO2 enrichment for either species possibly because of slow growth under low light. This study indicates the importance of direct effects of CO2 enrichment when predicting potential change in species distribution with global climate change.
3906,1994,2,2,EFFECTS OF GLOBAL WARMING ON HURRICANE-INDUCED FLOODING,Global simulation models used to predict climate change typically have resolutions too coarse for resolving small drainage basins| creating a major obstacle to evaluating the hydrologic impacts of climate variability. The writers circumvent this difficulty by using a physical model for severe hurricanes to derive changes in hurricane rainfall under a predicted global warming. The modified rainfall is then transferred to a linked hydrologic-hydrodynamic model to compute the impact of global warming on hurricane-induced flooding in a susceptible watershed. As an example| using simulations of tropical| doubled-CO2 climate change| the hurricane model predicts a 40% precipitation increase for severe hurricanes affecting southeastern Florida. The 40% increase is assumed for a 100-year| three-day event used for flood-management planning in South Florida and applied to the Basin Runoff and Streamflow Simulation (BRASS) model of the Western C-11 drainage system. The increased precipitation provokes substantially greater flooding that could negate most of the benefits of present water-management practices in this basin. 2630,1994,2,4,ELEVATED CO2 AND TEMPERATURE ALTER RECRUITMENT AND SIZE HIERARCHIES IN C-3 AND C-4 ANNUALS,In order to understand the implications of changes in global CO2 concentrations and temperature for the growth and fitness of individual plants| performance must be investigated in relation to the performance of other plants within a population. In this study we examined patterns of recruitment| mortality| and size structure of monospecific stands in response to ambient (400 mu L/L) and elevated CO2 concentrations (700 mu L/L) across three temperature regimes; 18 degrees| 28 degrees| and 38 degrees C. We created experimental populations of two annual plants that differ in their photosynthetic pathway and water use patterns: Abutilon theophrasti (C-3) and Amaranthus retroflexus (C-4). The effects of CO2| temperature| and their interactions on population structure were complex and species dependent. For both species increasing temperature resulted in higher germination and faster initial growth rates. These initial temperature responses increased the intensity and role of competition in determining stand size and structure. Postemergence responses to elevated CO2 differed markedly between the two species. For Abutilon| the C-3 species| serf-thinning and the mean biomass of the survivors increased under elevated CO2. For Amaranthus| survivorship| but not growth| increased under elevated CO2 conditions. We attribute differences in response between species not only to photosynthetic pathway| but also to differences in the onset of competition mediated through differences in plant form and in resource uptake and deployment. The patterns of stand development in response to CO2 and temperature suggest that the effects of changing CO2 and temperature may be understood within mechanistically based models of resource use. Temperature regulates the rate of resource use and the onset of interference among plants| while CO2 functions both as a resource and a resource regulator. Although mortality was concentrated later in stand development for Abutilon than Amaranthus| overall patterns of stand size and structure were similar for both species; mortality and size inequalities increased with increasing temperature and CO2. Because size is often correlated with fecundity| an increase in size hierarchies in response to elevated CO2| in conjunction with a decrease in survivorship| may result in a smaller effective population size. Our ability to predict changes in effective population size due to changing size hierarchies alone| however| should also consider developmental shifts in response to elevated CO2 that may result in| as in this study| a decrease in the minimum size at the onset of flowering.
3907,1994,4,2,ESTIMATION OF ENERGY INTENSITY AND STRUCTURE OF ENERGY-CONSUMPTION BASED ON INPUT-OUTPUT TABLE,The environmental problems are becoming more critical issues these days. The global warming problem caused by carbon dioxide is serious| because energy supply for modem industry depends on the usage of fossil fuel. Renewable energy usage is expected to be one of the key technology to reduce the emission of carbon dioxide. Energy systems| however| to gather the renewable energies are tend to be large due to the low energy density| and require large amount of initial input energy. The assessment of the amount of energy to produce equipment and to construct renewable energy system is essential to evaluate the efficiency of systems as energy producer. In this paper| energy intensity is evaluated using Input-Output table and several topics on the use of the table are discussed. The estimation of energy intensity gave reasonable values for Japanese Input-Output table of 1985. In the analysis of energy intensity using Input-Output table| the evaluation of electricity has several alternatives. A method is proposed to modify the structural matrix to manipulate electricity in a unified way. The effect of fixed capital depreciation is considered| which is not counted in normal way of Input-Output analysis. The result shows that the change in considering fixed capital is not so large for energy consumption structure in Japan. Two graphic methods to analyze the structure of Input-Output table are also considered. The inverse matrix coefficient that is the total sum of production to supply unit final demand| is plotted in a special graph to analyze the structure of energy flow from petroleum to automobiles and other products. The effect of transportation sector on the energy flow is analyzed by calculating and plotting inverse matrix coefficient from modified structural matrix. This paper suggests that Input-Output table is useful for energy analysis.
2613,1994,2,4,ESTIMATION OF LOCAL AND AREAL DROUGHT REFLECTING CLIMATE-CHANGE,A methodology is developed and applied to eastern Nebraska to estimate the statistical properties of a meteorological drought index under climate change. The approach is based on the analysis of atmospheric circulation patterns (CP)| followed by a stochastic linkage between daily CP types and daily local hydrometeorological quantities used to calculate the drought index. The methodology is illustrated with a common rainfall deficit-based drought index| the Bhalme-Mooley Drought Index (BMDI). Historical data and General Circulation Model (GCM) output of daily CP corresponding to the present (1xCO(2)) and doubled atmospheric CO2 (2xCO(2)) concentration are taken as inputs| Time series of both local and areal BMDI are simulated and their statistics are calculated. Under the dry continental climate of eastern Nebraska a highly variable spatial response to climate change has been obtained. Most of the local and the areal average drought indices reflect a somewhat wetter and a more variable climate under the 2xCO(2) conditions. The results may be sensitive to the GCM used. The methodology can be used elsewhere to estimate statistically the impact of global climate change on local/regional drought.
3908,1994,3,4,EUROPEAN RESEARCH CONCERNING CFC AND HCFC SUBSTITUTION,Four years ago| during the ASHRAE 1989 CFC Technology Conference| a presentation was given on European research into CFC substitution (CFC Research Activities in Europe/CFC Research Programmes in Western Europe)| which has been published in this journal. In August 1993| a follow-up conference| entitled 'ASHRAE/NIST Refrigerants Conference - R-22/R-502 Alternatives'| was held in order to discuss in particular substitutes for R502 and R22. Again| a presentation concerning European research on CFC and HCFC substitution was given and will be published in this journal. It will on the one hand| as a follow-up| deal with the progress of the research programmes listed four years ago and on the other hand mention new research programmes which have been established since then. The research projects have not only been influenced by the problem of ozone depletion but also by the growing discussion on global warming during the last four years. Therefore| the new projects deal especially with the application of old natural fluids in refrigeration and air-conditioning systems. 3905,1994,2,3,EVALUATING THE TYPE AND STATE OF ALASKA TAIGA FORESTS WITH IMAGING RADAR FOR USE IN ECOSYSTEM MODELS,Changes in the seasonal CO2 flux of the boreal forests may result from increased atmospheric CO2 concentrations and associated global warming patterns. To monitor this potential change| a combination of information derived from remote sensing data| including forest type and growing season length| and ecophysiological models which predict the CO2 fluX and its seasonal amplitude based on meteorological data| are required. In this paper we address the use of synthetic aperture radar (SAR) to map forest type and monitor canopy and soil freeze/thaw| which define the growing season for conifers| and leaf on/off| which defines the growing season for deciduous species. Aircraft SAR (AIRSAR) data collected in March 1988 during a freeze/thaw event are used to generate species maps and to determine the sensitivity of SAR to canopy freeze/thaw transitions. These data are also used to validate a microwave scattering model which is then used to determine the sensitivity of SAR to leaf on/off transitions and soil freeze/thaw. Finally| a CO2| flux algorithm is presented which utilizes SAR data and an ecophysiological model to estimate CO2 flux. CO2 flux MaPS are generated| from which areal estimates Of CO2 flux are derived. 3940,1994,5,4,EVOLUTIONARY MORPHOLOGICAL-CHANGES IN THE NEW GENUS DUOFORISA - IMPLICATION FOR CLASSIFICATION AND HABITAT OF THE UNILOCULAR FORAMINIFERA,Unlike other unilocular foraminifera| the new genus Duoforisa from the Late Oligocene to Early Miocene possesses a kidney-shaped test with two apertures on its distal ends. It contains two distinct and successional species| both new| and differentiated by their apertural details. In Duoforisa rima the apertures are slit-like| and become radial in the descendant D. diducta. Intermediate forms have transitional apertural configurations between the slit type and radial type. accompanied also by a change of the test outline from subtriangular to compactly U-shaped. The evolution of the lineage occurred during a period of enhanced upwelling in the Early Miocene and it was terminated just before the global warming at the Early-Middle Miocene boundary. This example suggests evolution of the unilocular foraminifera through successional morphological changes in test shape and in the aperture. Unilocular taxa have tended to flourish or speciate in cool or upwelling environments. Their contraction in the latest Early Miocene to early Middle Miocene was probably due to global warming and well oxygenated conditions which were widespread in the neritic domains of southern Australia.
3876,1994,2,5,EXTREME MINIMUM WINTER TEMPERATURES IN OHIO,The Extreme Minimum Winter Temperature (EMWT) is the coldest temperature recorded each winter at a given weather station. This variable is a measure of winter temperature severity. EMWT influences the geographic distribution of plants| and is a prime control for the production of some fruit crops grown in Ohio. EMWT values are often used to map plant hardiness zones| but climatic variables rarely remain constant over time| and plant hardiness zones could shift significantly if the climate of ohio changes and there is a change in EMWTs. EMWTs from 89 weather stations in ohio were analyzed to determine spatial patterns and time trends. Summary statistics of EMWTs were tabulated and mean EMWT was mapped at a large scale. Linear and polynomial regression were utilized to examine the time series. EMWTs have not warmed during the climatic record of this variable. There does not appear to be a link between EMWTs in Ohio and the increasing levels of CO2 in the atmosphere. The present study demonstrates the need for more research in applied climatology based on observed climate records| not obscured by the assumptions of the global warming paradigm.
3921,1994,3,2,FOREST-FIRE EMISSIONS IN PORTUGAL - A CONTRIBUTION TO GLOBAL WARMING,A forecast of expected evolution of carbon dioxide (CO2) emissions in Portugal between 1988 and 2010 is presented. Predictions show that CO2 emissions will almost double in the next twenty years. The equivalent potential CO2 emissions from nitrogen oxides (NO(x)) and volatile organic compounds (VOC)| for a time horizon of 20 years| is also presented NO(x) and VOC emissions seem to make a significant contribution to the global warming potential of Portuguese emissions. Estimates Of CO2 emissions due to forest fires have been made| oriented towards the study of the Portuguese contribution to the global warming. If the burned area exceeds 100000 ha this contribution could reach 7% of the total Portuguese CO2 emissions. The global warming potential of Portuguese forest fire emissions were also calculated The climate change predicted to Portugal could be responsible for an increase in the forest fires and consequently for a greater contribution of its emissions to the total values. It was concluded that it is important to quantify emissions of the greenhouse gases| including the contribution of forest fire emissions| not only in Portugal| but in all the Southern European countries. 3854,1994,3,3,FOSSIL-FUEL AND GREENHOUSE-GAS MITIGATION TECHNOLOGIES,The world has become highly alerted to the global warming problem. The major greenhouse gas is CO2| large quantities of which are produced by combustion of fossil fuels; coal being a major contributor. Whereas a great deal of effort is being expended on the science of climate change| very little work has gone into mitigation technologies. This is now changing. The options include improved energy utilization efficiency| fuel switching| non-fossil energy sources| and pre- and post-combustion removal and disposal of CO2 from central power stations. Another approach is the pre-combustion conversion of fossil fuel to a carbon-rich fraction and a hydrogen-rich fraction; storing the carbon-rich and only utilizing the hydrogen-rich fraction. By coprocessing with the biomass| the CO2 emission from fossil fuel can be reduced to negligible values. Assessment of these systems is discussed. 2635,1994,2,4,FRAMEWORK FOR ASSESSING EFFECTS OF GLOBAL CLIMATE-CHANGE ON MANGROVE ECOSYSTEMS,Ecological assessment represents a current approach to bridge scientific research and knowledge to the information needs in development of policy and management decisions. Mangrove ecosystems were chosen as a representative community type to examine available knowledge and develop approaches to detection and evaluation of the ecological responses to elements of global climate change. Risk assessments and ecological assessments have some parallel procedures and we briefly compare some common objectives and approaches. The focus of the discussions is in the context of ecological assessment| gathering and evaluating of data most relevant to the south Florida mangroves and associated habitats| and the framework to combine diverse sets of scientific data for the broader or more generalized perspectives and long-term information needs of policy formulation.
3858,1994,4,4,GLOBAL AND HEMISPHERIC TEMPERATURE TRENDS - UNCERTAINTIES RELATED TO INADEQUATE SPATIAL SAMPLING,Long-term (50 to 100 years) and short-term (10 to 30 years) global and hemispheric trends of temperature have an inherent unknown error due to incomplete and nonrandom spatial sampling. A number of experiments have been conducted to help quantify the potential magnitude of this error. The analysis includes the errors introduced into the climate record because of both incomplete global coverage and inadequate sampling within those areas presumed to have adequate observations. In these experiments it is found that the uncertainty in calculating historical temperature trends is dependent upon the pattern of temperature change| the method of treating the effect of nonrandom spatial sampling| and the time and length over which the trend is calculated but is relatively insensitive to the random errors associated with estimating regional-scale (grid cell size) temperature anomalies. Results imply that the errors associated with century-scale trends of temperature are probably an order of magnitude smaller than the observed global warming of nearly 0.5-degrees-C per 100 years since the late nineteenth century. The errors in estimates of decadal temperature trends are found to be large relative to century-scale trends and are unreliable during the nineteenth and early twentieth centuries. Even during the recent decade of the 1980s| the area-averaging techniques used in some analyses could be improved by addressing the over-sampling of Northern Hemisphere (especially over land) relative to the rest of the globe. Otherwise| significant positive biases are likely during the 1980s. These biases may have contributed to the reported differences between in situ surface and space-based temperatures during the 1980s. The rather encouraging results with respect to the magnitude of the spatial sampling errors associated with the calculation of long-term trends beginning in the nineteenth century cast a positive light on efforts aimed at extending the proxy and observed global temperature record further back in time| despite limited geographic coverage. 3912,1994,4,3,GLOBAL CHANGE MODELS - A PHYSICAL PERSPECTIVE,The World Climate Research Programme has the dual objectives of determining the extent of climate predictability and the influence of human activities on climate. To meet these objectives| the WCRP has instituted a set of research programs focusing on specific aspects of the physical climate system. Global climate models are at the core of the WCRP. Models provide a structural framework around which to organize research; they are used to identify knowledge gaps and to assimilate data; and they are used for prediction and simulation. Time scales of interest stretch from those of numerical weather prediction| through interannual variability to decadal climate change. As the time scale of interest expands we must include more and more components of the climate system. Physically-based global climate models will also be the framework upon which to build full global change models. Modelling and other research activities internationally coordinated by the WCRP have provided the basis for the Intergovernmental Panel on Climate Change (IPCC) assessment of global warming and the proposed international centre for climate prediction research. A major thrust of the WCRP is to reduce the uncertainties in simulations of climatic response to increasing concentrations of greenhouse gases. There is need for a continuous interaction between the modelling community and those scientists studying the processes and data. Through international coordination and national contributions considerable progress has been made over the past decade and we anticipate similar success in the future. 3901,1994,3,3,GLOBAL CLIMATE AND ENERGY-SYSTEMS,Consensus exists that further environmental pollution and climate change could be prevented if energy systems' emissions are significantly reduced. But energy will remain one of the most active driving forces of social and economic progress over the whole 21st century. This predetermines the necessity and expediency for long-term energy studies. Global energy systems recently have started the transition path from systems based on fossil fuels| with limited and exhaustible resources| to systems using inexhaustible or renewable energy resources (fission and fusion| solar| wind| biomass| geothermal| etc.). It is difficult to foresee exactly how long this transition period will last| because the rates of transition will depend on many factors - of which the most important will be energy costs at the end-user and the systems' impacts on humans| biosphere| and natural environment. Two global energy scenarios (Dynamic-as-Usual and Enhanced Energy Efficiency and Conservation| with several options for each of the scenarios) until the middle of the next century are discussed in the paper. According to energy projections| energy demand in developed countries is likely to stay at the current level over the whole time period or may even slightly decline (it is quite possible that in some countries with very high per capita energy demand| the reduction of primary energy consumption will start even in the near future). The major part of the energy demand growth worldwide will be justified by the needs of developing countries to improve their economic and social position. It is expected that primary energy demand in developing countries will increase by a factor of 3-5 compared to today's level. The world primary energy mix will very much depend on development strategies applied over the next 50-60 years. If a strategy for massive prevention of global warming is to be required| the share of fossil fuels in primary energy consumption must be remarkably reduced (even down to 25% in case of a 60% CO2 emission reduction until the middle of the next century as stated by IPCC). Electricity keeps its position as a most universal energy carrier in all sectors of end-use| including transportation. Environmental protection goals can be achieved with the most effective and less expensive ways through applying electric technologies. Therefore| a strong growth rate for electricity generation is projected in both regions - developed and developing countries. Even if radical steps are taken to prevent the impact of energy systems on global climate| the CO2 accumulation in the atmosphere will not be stopped. At the best| we can speak only of postponing the doubling of carbon concentration in the atmosphere for a couple of decades in the longer future. Parallel efforts within other spheres of the human activity are required: first of all| to stop deforestation of tropical forests| enhance reforestation| and reduce emissions of other greenhouse gases which in total contribute about 50% to global warming. The transition to an accelerated CO2 reduction policy will require about 4-5% of the world GNP spent on investments within energy systems| which is not significantly higher than today. However| the structure of investments must be drastically changed from energy production to energy conservation and savings. Large concerns exist in finding capital to provide these investments in developing countries because it will be hardly possible for them to accomplish energy/climate programs without strong assistance from the developed world. It would be naive to think that a global energy and climate change policy could be introduced without massive obligatory measures at the national and global levels- These measures should include policy actions| marketing guidelines| educational programs. financial mechanisms. and technology transfer. The realization of such a policy will require the creation of new institutional frameworks| with concerted efforts of all players on the international and national energy markets. However| there are still many unsettled questions that remain in global warming and in looking for effective response strategies. 2645,1994,4,4,GLOBAL CLIMATE-CHANGE IN THE INSTRUMENTAL PERIOD,The instrumental period of climate history began in the 18th century with the commencement of routine weather observations at fixed sites. Estimates of global-mean climate (eg. temperature and precipitation) were not possible| however| until the establishment of extensive observing networks midway through the 19th century. This paper reviews our knowledge of global climate change in the instrumental period Time series of global-mean temperature and precipitation are examined and a comparison is made between two independent 30-year climatologies: 1931-60 and 1961-90. Examples are also provided of regional-scale climate changes. Such assessments are important for two reasons. First| they establish the variability of climate on the time-scale of decades| time-scales upon which it is reasonable to plan economic and socio-political activities. Second| and more specifically| they enable us to quantify the magnitude of global-mean climate change which has occurred over this period Such detailed diagnostic climate information is a necessary| although not sufficient| prerequisite for the detection of global-scale warming which may have occurred due to the enhanced greenhouse effect. Some attention is given to explanations of the observed changes in global-mean climate.
3843,1994,4,3,GLOBAL DECREASE IN ATMOSPHERIC CARBON-MONOXIDE CONCENTRATION,CARBON monoxide plays an important role in the oxidizing capacity of the Earth's atmosphere| and may thereby indirectly affect the concentrations of many man-made and natural trace gases| which in turn affect climate| atmospheric chemistry and the ozone layer(1). CO is produced in the atmosphere by the oxidation of methane and other hydrocarbons| and is released into the atmosphere from automobiles| agricultural waste and the burning of savanna(1-4). Recent estimates' show that human activities such as these are presently responsible for more than half the annual emissions of CO. During the 1980s there was evidence that atmospheric CO concentrations were increasing at similar to 1.2 +/- 0.6% per year| leading to feedbacks that could amplify global warming. Here we present a continuation of these measurements which show that from 1988 to 1992 global CO concentrations have started to decline rapidly at a rate of about -2.6 +/- 0.8% per gear. A recent study(5) has verified our findings with data from the past 3-4 years. The rate of decrease is particularly rapid in the Southern Hemisphere; we hypothesize that this may reflect a reduction in tropical biomass burning. The total amount of carbon monoxide in the atmosphere is less now than a decade ago.
3855,1994,2,4,GLOBAL WARMING AND PERMAFROST IN EURASIA - A CATASTROPHIC SCENARIO,Since models of global warming predict that climatic changes will be greatest in the Arctic and might already be in progress| it is prudent to attempt to understand the rapidly changing thermal regime on Eurasian cold regions. In this paper the author tries to evaluate the probable catastrophic implications of global climatic change in the cold regions of Eurasia. The impact on Man activities in permafrost regions is discussed. 3919,1994,2,3,GLOBAL WARMING AND THE GROWTH OF ICE SHEETS,Recent research has suggested that warmer conditions| that may result from increased levels of CO2 in the atmosphere| may induce the growth of the Northern Hemisphere ice sheets (Miller and de Vernal 1992) through the impact of warmer temperature on the water carrying capacity of the atmosphere and thus on precipitation. In this study we examine this possibility by using a coupled energy balance climate-thermodynamic sea ice model. Results indicate that if summer ice albedo is high enough| and there is some mechanism for initially maintaining ice through the summer season| then it may be possible to have ice sheet growth under the conditions of CO2 induced warming. 3925,1994,4,1,GREENHOUSE STATISTICS - TIME-SERIES ANALYSIS .2.,The analysis of part I (Tol and de Vos| 1993) is supplemented| updated and refined| and the resolution bound of simple statistical analysis is tentatively explored. The main conclusion of part I| the hypothesis that the anthropogenically enhanced greenhouse effect is not responsible for the observed global warming during the last century is rejected with a 99% confidence| is reconfirmed for the updated sample period 1870-1991. The slight decrease in the global mean temperature between 1940 and 1975 is attributed to the influence of El Nino and the volcanic activity. The influence of sunspots| or the length of the solar cycle| is found to be small and unlikely to have caused the observed global temperature rise. The analysis of a number of alternative records lowers the significance of the influence of the enhanced greenhouse effect to 95%. The temperatures on the northern hemisphere rise a little faster than the southern hemisphere temperatures; this distinction is not significant but in line with the larger amount of land at the northern hemisphere. Some indications are found of an unexplained four year cycle in the temperatures of the northern hemisphere. Winter temperatures rise fastest| summer temperatures slowest; this is more profound on the northern than at the southern hemisphere. The difference is not significant; it could be due to the influence of anthropogenic aerosols. The analysis of monthly temperatures confirms the conclusions above| and shows that the models used here are close to being too simple to be used at this resolution. 3870,1994,2,3,GREENHOUSE-GAS AND SULFATE AEROSOL EXPERIMENTS USING A SIMPLE GLOBAL-ENERGY-BALANCE MODEL,A one-dimensional global-energy-balance model is used to simulate the climate response of increasing atmospheric green house gas concentrations and sulfate aerosol loadings. Model output indicates that a change in equivalent carbon dioxide from 300 to 450 ppm produces a global warming of 0.69 degrees C (1.24 degrees F)| and a doubling to 600 ppm generates a warming of 1.57 degrees C (2.83 degrees F). In both simulation experiments| the greatest warming appears in the high latitudes of the Northern Hemisphere. Model results show that increasing sulfate aerosol levels generates a global cooling of 0.32 degrees C (0.58 degrees F)| with the largest cooling occurring in the industrialized mid-to-h igh latitudes of the Northern Hemisphere. When the effects of equivalent carbon dioxide and sulfates are simulated together to represent changes that have occurred in the past century| the model generates a global warming of 0.30 degrees C (0.54 degrees F)| with the greatest warming continuing to occur in the mid-to-high latitudes of the Northern Hemisphere. The latent heat transfer values| which provide a rough indication of projected trends in precipitation levels| increase globally by 2.3% as the model's representation of atmospheric composition is perturbed by greenhouse gases and sulfate aerosols. These basic results from the simple one-dimensional energy balance model are broadly consistent with simulations using far more sophisticated three-dimensional general circulation models and with the trends in global temperature and precipitation observed over the past century. 3857,1994,3,4,HEALTH AND THE BUILT ENVIRONMENT,Two opposing trends threaten the architect and engineer. The first is concern for global pollution. Not only energy use but also energy sources will be defined in terms of atmospheric contamination. Annual carbon dioxide targets will be established. Architects will have to become more energy conscious and numerate. The second is a demand for a performance specification for a more satisfying indoor climate. Engineers will have to pay higher regard to the inhabitants and quantify occupant satisfaction. Building design will be performance based both in terms of external pollution and guaranteed internal conditions. 2618,1994,2,4,HOLOCENE SEA-LEVEL RISE AND THE FATE OF MANGROVE FORESTS WITHIN THE WIDER CARIBBEAN REGION,This paper (1) reviews mangrove forest peat accretion data obtained from carbonate settings of the Wider Caribbean Region and (2) evaluates the fate of these forests based upon current global eustatic sea-level rise projections. Historical peat accretion rates calculated using Cs-137 or Pb-219 average 3.7 mm yr(-1). Feat accretion rates calculated using C-14 average 1.0 mm yr(-1). The discrepancy between historical and geological accretion rates| also recognized in salt marsh settings| is attributed to organic decomposition and sediment compaction. Our conceptual model| which is based upon comparisons between projected rates of global eustatic sealevel rise and peat secretion| predicts stable forest conditions only it historical accretion rates persist during a conservative (low) sea-level rise of similar to 1.3 mm yr(-1). Best guess (middle) and high estimates of a sea-level rise of as much as 8 mm yr(-1) will likely submerge mangrove forests located within carbonate settings of the Wider Caribbean Region.
2619,1994,4,4,IDENTIFYING REGIONAL GOALS AND POLICY CONCERNS ASSOCIATED WITH GLOBAL CLIMATE-CHANGE,This paper presents a systematic approach| assisted by analytic hierarchy process (AHP) and goal programming (GP)| to build a bridge between science and policy in a regional climate change impact study. The approach is being applied in the Mackenzie Basin of Canada. The study focuses on the identification and specification of regional policy concerns relating to climate change. The approach attempts to ensure that the outputs of the climate change impact study reflect some major concerns of various regional 'stake holders'.
3822,1994,2,3,IMPACT OF INCREASED CO2 ON SIMULATED ENSO-LIKE PHENOMENA,The impact of a CO2-induced global warming on ENSO-like fluctuations in a global coupled ocean-atmosphere GCM is analyzed using two multi-century experiments. In the 4xCO2 experiment| CO2 increases by a factor of four in the first 140 years and then remains constant at 4xCO2 for another 360 years; in the control experiment| CO2 remains constant at 1xCO2 for 1000 years. The standard deviation of tropical Pacific SST fluctuations (7-degrees-N-7-degrees-S| 173-degrees-E-120-degrees-W; 2 to 15 year timescales) is 24% lower in the 4xCO2 experiment than in the control experiment; for the model's Southern Oscillation Index| a 19% decrease occurs| whereas for central tropical Pacific rainfall| a 3% increase occurs. An important feature of the control simulation is the internally generated modulation of variability on a multi-century timescale| which is comparable in magnitude to the changes occurring with 4xCO2. We conclude that despite an order 5 K warming of the tropical Pacific| and order 50% increase in time-mean atmospheric water vapor under 4xCO2 conditions| ENSO-like SST fluctuations in the coupled model do not intensify| but rather decrease slightly in amplitude. 2620,1994,4,3,IMPLICATIONS FOR ENERGY AND CLIMATE-CHANGE POLICIES OF USING PURCHASING-POWER-PARITY-BASED GDP,There is a much better correlation between energy use and GNP or GDP when the latter are calculated using purchasing-power parity (PPP) rather than market-exchange rates (MER). Using PPP-adjusted GDP also shows that the larger developing countries of the world are not| when viewed overall| less energy-efficient than their industrialized country counterparts. The per capita GDPs of the larger developing countries are typically about 1/10 to 1/4 of those of the O.E.C.D. countries| on a PPP-adjusted basis| rather than in the range of 1/80 to 1/10 on an MER-basis. This result may have major implications for future energy requirements of the developing countries| associated emissions of CO2| and formulation of policies for addressing global climate change.
3842,1994,3,3,INDUSTRIAL AND NONINDUSTRIAL ANTHROPOGENIC INPUTS TO THE GLOBAL BIOGEOCHEMICAL CYCLES - IMPLICATIONS FOR INTERTEMPORAL ENVIRONMENTAL-POLICY,The majority of developing nations continue to rely primarily of biomass energy sources even as they endeavor to modernize and industrialize their economic base. The implications of this dependence include a strong linkage between pre-industrial conditions and future national development| as well as the need for environmental planning that explicitly recognizes the natural time-scales of ecological change. Environmental policy analysts consequently must work with this mix of resources and constraints as well as the political and managerial environment generated by recent concerns over global warming and change. To develop a framework for evaluating longterm environmental impacts| we first elaborate on an earlier time-line model of pre-industrial anthropogenic carbon emissions (Kammen and Marine| 1993). We then examine the implications of environmental decision making necessitated by natural time-scales of forest growth| the natural biogeochemical cycles| and the anthropogenic release of trace gasses. This perspective provides a number of insights into sustainable levels of land-conversion for agricultural activity and biomass utilization| and more generally sets natural time-horizons that must be integrated into the planning of strategies for development and economic growth. 3828,1994,2,4,INFLUENCE OF WATER-TABLE ON CARBON-DIOXIDE| CARBON-MONOXIDE| AND METHANE FLUXES FROM TAIGA BOG MICROCOSMS,Hydrological changes| particularly alterations in water table level| may largely overshadow the mole direct effects of global temperature increase upon carbon cycling in arctic and subarctic wetlands. Frozen cores (n=40) of intact soils and vegetation were collected from a bog near Fairbanks| Alaska| and fluxes of CO2| CH4| and CO in response to water table variation were studied under controlled conditions in the Duke University phytotron. Core microcosms thawed to a 20-cm depth over 30 days under a 20 hour photoperiod with a day/night temperature regime of 20/10 degrees C. After 30 days the water table in 20 microcosms was decreased from the soil surface to -15 cm and maintained at the soil surface in 20 control cores. Outward fluxes of CO2 (9-16 g m(-2) d(-1)) and CO (3-4 mg m(-2) d(-1)) were greatest during early thaw and decreased to near zero for both gases before the water table treatment started. Lower water table tripled CO2 flux to the atmosphere when compared with control cores. Carbon monoxide was emitted at low rates from high water table cores and consumed by low water table cores. Methane fluxes were low (<1 mg m(-2) d(-1)) in all cores during thaw. High water table cores increased CH4 flux to 8-9 mg m(-2) d(-1) over 70 days and remained high relative to the low water table cores (<0.74 mg m(-2) d(-1)). Although drying of wetland taiga soils may decrease CH4 emissions to the atmosphere| the associated increase in CO2 due to aerobic respiration will likely increase the global warming potential of gas emissions from these soils. 2657,1994,2,4,INFLUENCES OF SOIL VOLUME AND AN ELEVATED CO2 LEVEL ON GROWTH AND CO2 EXCHANGE FOR THE CRASSULACEAN ACID METABOLISM PLANT OPUNTIA-FICUS-INDICA,Effects of the current (38 Pa) and an elevated (74 Pa) CO2 partial pressure on root and shoot areas| biomass accumulation and daily net CO2 exchange were determined for Opuntia ficus-indica (L.) Miller| a highly productive Crassulacean acid metabolism species cultivated worldwide. Plants were grown in environmentally controlled rooms for 18 weeks in pots of three soil volumes (2 600| 6 500 and 26 000 cm3)| the smallest of which was intended to restrict root growth. For plants in the medium-sized soil volume| basal cladodes tended to be thicker and areas of main and lateral roots tended to be greater as the CO2 level was doubled. Daughter cladodes tended to be initiated sooner at the current compared with the elevated CO2 level but total areas were similar by 10 weeks. At 10 weeks| daily net CO2 uptake for the three soil volumes averaged 24% higher for plants growing under elevated compared with current CO2 levels. but at 18 weeks only 3% enhancement in uptake occurred. Dry weight gain was enhanced 24% by elevated CO2 during the first 10 weeks but only 8% over 18 weeks. Increasing the soil volume 10-fold led to a greater stimulation of daily net CO2 uptake and biomass production than did doubling the CO2 level. At 18 weeks| root biomass doubled and shoot biomass nearly doubled as the soil volume was increased 10-fold; the effects of soil volume tended to be greater for elevated CO2. The amount of cladode nitrogen per unit dry weight decreased as the CO2 level was raised and increased as soil volume increased| the latter suggesting that the effects of soil volume could be due to nitrogen limitations.
3836,1994,4,4,INVESTIGATION OF THE CORRELATION BETWEEN THE ENERGY OF THE HIGHEST OCCUPIED MOLECULAR-ORBITAL (HOMO) AND THE LOGARITHM OF THE OH RATE-CONSTANT OF HYDROFLUOROCARBONS AND HYDROFLUOROETHERS,A regression based model was developed to determine whether highest occupied molecular orbital (HOMO) energies| calculated using Kohn-Sham orbital density functional theory (DFT)| could be used to estimate the OH rate constants of hydrofluorocarbons (HFCs) and hydrofluoroethers (HFEs)| proposed substitutes for stratospheric O3 depleting chlorofluorocarbons. The goodness of fit of the DFT model was compared with a second regression model| derived using recently reported HOMO energies obtained from Hartree Fock theory (HFT). Both models were employed to predict OH rate constants for a number of HFCs and HFEs whose OH rate constants have not been measured| thus providing data on the types of chemical structures that may increase the OH reactivity of the substitute and hence decrease its contribution to global warming. The estimated percent standard errors in the OH rate constant HFT and DFT regression models were 72% and 78%| respectively. The goodness of fits were such that the models can differentiate between two rate constants only when their ratio exceeds about a factor of four. Model results suggest that (1) only a limited number of HFEs will have OH rate constants that are more than an order of magnitude greater than the value for their corresponding HFCs and (2) the strategy of introducing an ether linkage into an HFC to dramatically enhance its reactivity will be most effective for the least fluorinated HFCs. (C) 1994 John Wiley & Sons| Inc.dagger 3815,1994,5,3,IS EARTH CLIMATE POISED TO JUMP AGAIN,Considerable concern exists regarding the possible climatic effects of the buildup of greenhouse gases in Earth's atmosphere. Computer simulations of atmospheric circulation models suggest that the modern climate system is well-behaved and will undergo a gradual warming. But the climate record for the last 100|000 years shows a quite different pattern of temperature change. Rather than obediently performing to the tune of Milankovitch orbital cycles| temperatures have jumped with alarming abruptness from warm to cold. Millennia-long periods of relatively steady climate were repeatedly disrupted by decade-long leaps to very different climate states.
3868,1994,3,2,IS NATURAL-GAS REALLY THE ANSWER - TARGETING NATURAL-GAS IN UNITED-STATES CLIMATE-CHANGE MITIGATION POLICY,Since use of natural gas emits less carbon dioxide (CO2) than other fossil fuels and CO2 is an important greenhouse gas| policies to encourage greater natural gas use are often touted as one strategy to reduce global warming. In this analysis| we examine the impacts of lower natural gas prices| brought about by government initiatives or market forces| on greenhouse gas emissions. The most surprising result of this analysis is that lower gas prices appear to have little impact on US greenhouse gas emission trends. However| lower gas prices and commensurate overall lower fossil energy costs do defer energy conservation efforts| stimulate more energy use economy-wide| and may displace cleaner renewable sources of energy. These results argue for a careful examination of attributes needed to align policy options intended to increase efficient gas use and those intended to lower overall greenhouse gas emissions. 3879,1994,3,3,ISSUES SURROUNDING THE USE OF LEAD IN GASOLINE - ENERGY| ECONOMIC AND ENVIRONMENTAL,The use of lead is still the most energy-efficient and cost-effective way to improve gasoline octane quality. It is argued that there is no demonstrable evidence that lead's use as a gasoline additive results in any adverse health effects. Potential environmental hazards exist with low-lead and unleaded gasolines. Furthermore| emissions of carbon dioxide| the 'greenhouse' gas implicated in global warming| increase when gasoline lead levels are restricted and cars are fitted with three-way catalysts.
3861,1994,2,4,KUWAITI OIL FIRES - MODELING REVISITED,Just after the invasion of Kuwait| scientists began predictions on the environmental disaster due to threat by the Iraqi regime to blow out oil wells in the Kuwaiti oil fields. The findings with the speculations ranging from a nuclear winter to super-acid rain and global warming were presented in the World Climate Conference in Geneva in November 1990. Just before the war erupted in the middle of January 1991. a conference in London was called to discuss the potential risks to human life and ecological systems in case of blow out of oil fields. The scientists| using modeling techniques| raised the speculations about the global impact which| however| was discounted at a later stage. This paper presents an overview of the selected models used to assess the local| regional| and global impacts. The paper also highlights the model and data limitations and suggests future research directions to respond more effectively under emergency situations. 3893,1994,3,3,LANDFILL GAS PRETREATMENT FOR FUEL-CELL APPLICATIONS,The US Environmental Protection Agency (EPA) has proposed regulations [1] to control air emissions from municipal solid waste landfills. If these regulations are adopted| they would require waste methane mitigation in order to prevent emission into the atmosphere and reduce the effect on global warming. One potential use of the waste methane is in a device which produces energy| the fuel cell. This device would reduce air emissions affecting global warming| acid rain| and other health and environmental issues. By producing useable energy| it would also reduce our dependency on foreign oil. This paper discusses the US EPA program underway at International Fuel Cells Corporation to demonstrate landfill methane control| and the fuel cell energy recovery concept. In this program| two critical issues needed to be addressed: (i) a landfill gas cleanup method that would remove contaminants from the gas sufficient for fuel cell operation| and (ii) successful operation of a commercial fuel cell power plant on that lower-heating value waste methane gas. 2637,1994,5,4,LATE QUATERNARY POLLEN TRANSPORT PROCESSES| WESTERN NORTH-ATLANTIC - DATA FROM BOX MODELS| CROSS-MARGIN AND N-S TRANSECTS,Surface pollen assemblages in coastal and neritic sediments of the western North Atlantic compare well with eastern North American vegetation zones| and late Quaternary pollen in marginal marine sediments clearly correlate with changes in terrestrial vegetation and paleoclimates. In contrast| offshore assemblages are strongly affected by differential adaptation of pollen to long distance transport by wind and water. Marine pollen transport processes were studied by measuring air and water inputs to a coast-shelf box model| and by study of surface samples from cross-margin transects in three different climatic and oceanographic regions at approximately 38-degrees| 45-degrees and 55-degrees-N latitude. The box model shows that aerial transport is the main process by which pollen moves across the continental margin off Nova Scotia. Two clear seabed distribution patterns were found: Betula| Quercus| and herb pollen decrease rapidly offshore in abundance (grains per cubic centimetre) and in relative abundance (percentage); Pinus and Picea have abundance peaks on the continental margin| but percentages increase further offshore. Distributions of the main pollen and spore taxa were compared for late Wisconsinan glacial (oxygen isotopic stage 2| 12-28 ka)| terminal Pleistocene (10-12 ka) and Holocene sediments at 5 continental margin and 3 deep-sea sites. The largest changes were found in percentages of Pinus| Picea| and herb pollen during the late Wisconsinan glacial and terminal Pleistocene intervals at subpolar latitudes. These data can be related to shifts in paleo-vegetation| -winds and -hydrology that accompany global climate change.
3849,1994,3,3,LIFE-CYCLE ANALYSIS TO MINIMIZE GLOBAL WARMING IMPACT,This paper describes a technique to identify the effects on potential global warning of waste| of both energy and materials| in the areas of refrigeration and air-conditioning. Such equipment always uses energy and generally contains an chemical driving fluid. The calculation converts emissions of the driving fluids and the energy used to run the equipment into the equivalent Warning Impact (TEWI). Examples show that the switch from CFCs to HFCs should result in marked reductions in the potential for global warning from refrigeration and air-conditioning and that the TEWIs of hermetically sealed systems are influenced more by energy efficiency than the effect of total loss of the driving fluid. The technique may be applied with equal facility in areas other than refrigeration. 2650,1994,4,3,LOCAL TEMPERATURE ESTIMATION UNDER CLIMATE-CHANGE,A methodology to estimate the space-time distribution of daily mean temperature under climate change is developed and applied to a central Nebraska case study. The approach is based on the analysis of the Markov properties of atmospheric circulation pattern (CP) types| and a stochastic linkage between daily (here 500 hPa) CP types and daily mean temperatures. Historical data and general circulation model (GCM) output of daily CP corresponding to 1 x CO2 and 2 x CO2 scenarios are considered. The relationship between spatially averaged geopotential height of the 500 hPa surface - within each CP type - and daily mean temperature is described by a nonparametric regression technique. Time series of daily mean temperatures corresponding to each of these cases are simulated and their statistical properties are compared. Under the climate of central Nebraska| the space-time response of daily mean temperature to global climate change is variable. In general| a warmer climate appears to cause about 5-degrees-C increase in the winter months| a smaller increase in other months with no change in July and August. The sensitivity of the results to the GCM utilized should be considered.
2651,1994,2,4,LONG-TERM CHANGES IN ANNUAL RAINFALL PATTERNS IN SOUTHERN ISRAEL,Within the study region in southern Israel| the annual average rainfall during the period 1961-1990 increased by up to approximately 30%| with only minor changes in the control stations representing the central and northern parts of the country. The retreat of aridity is made even more pronounced by an appreciable decrease in the coefficient of variation (CV) in nearly all of the 30 rain stations within the study region. The geographical area where maximum CV reductions were found correlates well with the area where intensive land-use variations took place with the initial operation of the National Water Carrier in 1964. A global climate change in the sea surface temperatures starting in the early 1960's may have had an effect to increase seasonal rainfall. Current research is aimed at resolving this issue.
3927,1994,2,4,Marine sediments as a source of atmospheric methane,Methane sources and sinks have been evaluated at 10 sites off the east coasts of Canada and Russia. More than 99% of the diffusive methane flux from marine sediments appears to be consumed by microbial oxidation when dissolved sulfate is present. At 3 sites| methane bubble vents were found. Two of the vents| located in the Okhotsk Sea| appear to result from gas being released along faults. The third plume site was located in a shallow harbour where a large amount of organic carbon is deposited in shallow water. The global diffusive and advective (bubbles) release of methane to the atmosphere from marine sediments is estimated to fall into the range of 1 - 10 TgC a(-1) (l Tg = 10(12) g). Researchers have speculated that marine gas hydrate deposits hold vast quantitites of methane that may melt and be released as a result of global warming. A warmer atmosphere could directly heat the ocean and/or change ocean current systems| which could bring warmer water to some areas. Hydrate samples were recovered from two sites in the Okhotsk Sea. These deposits| in 700 to 800 m of water| would require water temperatures to increase by 8 degrees C in order to melt the hydrate. Quantitative estimates of hydrate reservoirs near the minimum pressure stability zone are needed to remove the uncertainty whether this will be a significant positive feedback loop for global warming. 2611,1994,5,4,MASSIVE ICEBERG DISCHARGES AS TRIGGERS FOR GLOBAL CLIMATE-CHANGE,Observations of large and abrupt climate changes recorded in Greenland ice cores have spurred a search for clues to their cause. This search has revealed that at six times during the last glaciation| huge armadas of icebergs launched from Canada spread across the northern Atlantic Ocean| each triggering a climate response of global extent.
3875,1994,4,5,MAXIMUM AND MINIMUM TEMPERATURES AT ARMAGH-OBSERVATORY| 1844-1992| AND THE LENGTH OF THE SUNSPOT CYCLE,The question of whether or not the Earth's climate is influenced by solar activity has received considerable attention since the mid-nineteenth century. Most investigations have adopted the sunspot number as the parameter of solar activity. Recently| however| it has been shown by Friis-Christensen and Lassen (1991) that the mean northern hemisphere temperature| from 1861-1990| follows a strikingly similar trend to the length of the sunspot cycle| suggesting that the recent global warming could| at least in part| arise from changes in solar activity. In view of the importance of this result| we have examined a set of continuous meteorological records| maintained at Armagh Observatory since 1844| to assess| first| whether data from a single site can give meaningful information on global trends| and second| whether the data from this particular site for the period 1844-1866 can be used to extend the baseline of the comparison with solar activity. We find that both are indeed the case and that there is a strong correlation between the solar cycle length and the mean temperature at Armagh over the past 149 years.
2641,1994,4,4,MEASUREMENT OF TROPOSPHERIC OH AND HO2 BY LASER-INDUCED FLUORESCENCE AT LOW-PRESSURE,The hydroxyl radical (OH) is the primary oxidant in the atmosphere| responsible for many photochemical reactions that affect both regional air quality and global climate change. Because of its high reactivity| abundances of OH in the troposphere are less than 1 part per trillion by volume (pptv) and thus difficult to measure accurately. This paper describes an instrument for the sensitive detection of OH in the troposphere using low-pressure laser-induced fluorescence. Ambient air is expanded into a low-pressure detection chamber| and OH is both excited and detected using the A2SIGMA+(v' = 0) --> X2PI(v'' = 0) transition near 308 nm. An injector upstream of the detection axis allows for the addition of reagent NO to convert ambient HO2 to OH using the fast reaction HO2 + NO --> OH + NO2. Using recent advances in laser and detector technologies| this prototype instrument is able to detect less than 1 X 10(5) molecules cm-3 (0.004 pptv) of OH with an integration time of 30 s with negligible interferences.
3930,1994,3,2,METHANE AND NITROUS-OXIDE EMISSIONS - AN INTRODUCTION,Methane and nitrous oxide are important greenhouse gases. They contribute to global warming. To a large extent| emissions of methane and nitrous oxide are connected with the intensification of food production. Therefore| feeding a growing world population and at the same time controlling these emissions is a great challenge. Important anthropogenic sources of biogenic methane are wet rice fields| cattle| animal waste| landfills and biomass burning. Important anthropogenic sources of biogenic nitrous oxide are land-use change| fertilizer production and use and manure application. The ultimate objective of the Framework Convention on Climate Change implies a stabilization of greenhouse gas concentrations in the atmosphere. As a small first step towards achieving this objective| the Convention requires the industrialized countries to bring their anthropogenic emissions of greenhouse gases by 2000 back to 1990 levels. It was also agreed that all parties would make national inventories of anthropogenic greenhouse gas emissions and programmes for control (UN| 1992). In this context| in February 1993 an international workshop was held in Amersfoort in the Netherlands to discuss methods in national emission inventories for methane and nitrous oxide| and options for control (Van Amstel| 1993). A selection of the papers presented in Amersfoort that focus on agricultural sources is published in this volume. This introductory chapter gives background information on biogenic sources and sinks of methane and nitrous oxide and options for their control. The goal of the Climate Convention is described as well as the IPCC effort to develop an internationally accepted methodology for the monitoring of greenhouse gas emissions and sinks. Finally| some preliminary results from country inventories are given. It is concluded that a common reporting framework and transparency of the inventories are important to obtain comparable results that can be used for complying with the requirements of the Climate Convention and for facilitating the international debate about appropriate response 3904,1994,3,4,METHANE EMISSION FROM RICE PADDY FIELDS IN THE CENTRAL PLAIN OF THAILAND,Emission rates of CH| from rice paddy fields were measured in the central plain of Thailand. The measurements taken monthly during the cultivation periods showed a significant difference in CH4 emission rates among three sites. One paddy field| in Suphan Buri| showed a relatively high emission of CH4| with average fluxes of 19.5-32.2 mg m-2 h-1. The average fluxes from the other two paddy fields| in Khlong Luang and Chai Nat| were 3.8 and 1.6 Mg M-2 h-1| respectively| being one order of magnitude lower than those from Suphan Buri. The low emission of CH4 at the two sites was attributed to the high concentration of sulfate in soil or the high soil Eh due to the lower abundance of the reducing capacity in relation to the oxidizing capacity of soil. The results suggest that it is essential to provide a data base of soil characteristics| such as soil type and chemical composition of soil affecting the oxidation-reduction process| as well as conduct extensive field measurements in various rice growing countries to evaluate the global emission rates of CH4 from rice paddy fields. 3884,1994,3,3,METHODS FOR EXPLORING MANAGEMENT OPTIONS TO REDUCE GREENHOUSE-GAS EMISSIONS FROM TROPICAL GRAZING SYSTEMS,Increasing atmospheric concentrations of 'greenhouse gases' are expected to result in global climatic changes over the next decades. Means of evaluating and reducing greenhouse gas emissions are being sought. In this study an existing simulation model of a tropical savanna woodland grazing system was adapted to account for greenhouse gas emissions. This approach may be able to be used in identifying ways to assess and limit emissions from other rangeland| agricultural and natural ecosystems. GRASSMAN| an agricultural decision-support model| was modified to include sources| sinks and storages of greenhouse gases in the tropical and sub-tropical savanna woodlands of northern Australia. The modified model was then used to predict the changes in emissions and productivity resulting from changes in stock and burning management in a hypothetical grazing system in tropical northeastern Queensland. The sensitivity of these results to different Global Warming Potentials (GWPs) and emission definitions was then tested. Management options to reduce greenhouse gas emissions from the tropical grazing system investigated were highly sensitive to the GWPs used| and to the emission definition adopted. A recommendation to reduce emissions by changing burning management would be to reduce fire frequency if both direct and indirect GWPS of CO2| CH4| N2O| CO and NO are used in evaluating emissions| but to increase fire frequency if only direct GWPS of CO2| CH4 and N2O are used. The ability to reduce greenhouse gas emissions from these systems by reducing stocking rates was also sensitive to the GWPs used. In heavily grazed systems| the relatively small reductions in stocking rate needed to reduce emissions significantly should also reduce the degradation of soils and vegetation| thereby improving the sustainability of these enterprises. The simulation studies indicate that it is possible to alter management to maximise beef cattle production per unit greenhouse gases of per unit methane emitted| but that this is also dependent upon the emission definition used. High ratios of liveweight gain per unit net greenhouse gas emission were found in a broadly defined band covering the entire range of stocking rates likely to be used. In contrast| high values of liveweight gain per unit 'anthropogenic' greenhouse gas emission were found only at very low stocking rates that are unlikely to be economically viable. These results suggest that policy initiatives to reduce greenhouse gas emissions from tropical grazing systems should be evaluated cautiously until the GWPs have been further developed and the implications of emission definitions more rigorously determined. 3800,1994,5,4,MIOCENE UPWELLING EVENTS - NERITIC FORAMINIFERAL EVIDENCE FROM SOUTHERN AUSTRALIA,The neritic stratigraphic section in the Lakes Entrance oil shaft in Gippsland| Victoria| southeastern Australia| records four major upwelling events at the third-order or 10(6) years scale. The first and second occurred during the Janjukian (latest Oligocene to Early Miocene; at about 24.5 and 22 Ma); the third in the late Longfordian (late Early Miocene; 17.5-17 Ma); and the fourth at about 9-8 Ma in the Mitchellian (Late Miocene). The evidence for upwelling consists of concurrent signals from the planktonic and the benthic foraminifera. The four upwelling events are characterized by a low specific diversity in the plankton| a high abundance of the planktonic species Globigerina bulloides| and a high sedimentation rate (> 2 cm/ka). Among the benthos| such infaunal species as Uvigerina proboscidea increased in abundance and the mixing of normally separate deeper and shallow-water taxa was common. The ratio of epifaunal to infaunal benthic foraminifera increases through the Miocene as a second-order secular trend (10(7) a) but it is marked by four strong reversals which are the four events. It is suggested that the northerly fluctuation of the Subtropical Convergence was largely responsible for the fourth of these events. The others| however| are on the rising second-order trends in global warming and sea level and they alternate with warming events recognized on the occurrence of larger benthic foraminifera. The 'upwelling events' and the 'warming events' occur at the same third-order scale as the putative eustatic cycles of sequence stratigraphy and the Mi glaciations based on oceanic delta(18)O fluctuations. The upwelling events are neritic signals of global oceanic changes| of which the most marked is at the third| situated at the onset of the Monterey carbon isotope excursion. The Miocene climatic optimum at the zeniths of high sea level and warm climate lacks an 'upwelling event'. At this time there was a sharp reversal to oligotrophic conditions| a reversal seen also in the shallower and more restricted sea in the Murray Basin. 3910,1994,4,3,MODEL ASSESSMENT OF THE ROLE OF NATURAL VARIABILITY IN RECENT GLOBAL WARMING,SINCE the late nineteenth century| the global mean surface air temperature has been increasing at the rate of about 0.5 degrees C per century(1-3)| but our poor understanding of low-frequency natural climate variability has made it very difficult to determine whether the observed warming trend is attributable to the enhanced greenhouse effect associated with increased atmospheric concentrations of greenhouse gases(4|5). Here we evaluate the observed warming trend using a 1|000-year time series of global temperature obtained from a mathematical model of the coupled ocean-atmosphere-land system. We find that the model approximately reproduces the magnitude of the annual to interdecadal variation in global mean surface air temperature. But throughout the simulated time series no temperature change as large as 0.5 degrees C per century is sustained for more than a few decades. Assuming that the model is realistic| these results suggest that the observed trend is not a natural feature of the interaction between the atmosphere and oceans. Instead| it may have been induced by a sustained change in the thermal forcing| such as that resulting from changes in atmospheric greenhouse gas concentrations and aerosol loading. 3848,1994,4,3,MODELING OF SOIL CARBON DYNAMICS AS A PART OF CARBON-CYCLE IN TERRESTRIAL ECOSYSTEMS,Global warming by the increase of atmospheric CO2 concentration is one of the serious global environmental problems. For the investigations on the causes of atmospheric CO2 increase and the precisely predictions of future global warming| it is essential to understand the global carbon cycle among the atmosphere| terrestrial ecosystems and ocean| and to describe it by mathematical models on the basis of ecology and engineering. As a first step for constructing such a carbon cycle model| we previously developed a model describing the carbon exchange between the atmosphere and the terrestrial ecosystems| where the carbon dynamics in soil were significantly simplified as the first approximation. In this work a dynamic model describing the soil carbon dynamics was developed to improve the carbon cycle model for the terrestrial ecosystems. The vertical distribution of soil carbon and the soil carbon content in various kinds of soil were in good agreement with those previously reported in the literature. The total carbon content in soil over the world was also estimated by using the model. It can be said that a model of soil carbon dynamics working as a part of carbon cycle model between the atmosphere and terrestrial ecosystems was established. 3834,1994,2,4,MODELING PREINDUSTRIAL C-N-P-S BIOGEOCHEMICAL CYCLING IN THE LAND COASTAL MARGIN SYSTEM,Human activities were important forcing functions in the pre-industrial world and have become increasingly more important in the 21st century. Because of both natural temperature changes and pre-industrial anthropogenic activities| the carbon and nitrogen cycles were not in steady state prior to the Industrial Revolution and the beginning of important fossil fuel emissions to the atmosphere. In order to examine the role of the land-coastal margin system in global climate forcing and to assess changes in element cycling in response to natural and anthropogenic forcings| we have developed a conceptual model for the C-N-P-S biogeochemical cycles in this critical ecological zone. To demonstrate the application of the model| we evaluate the behavior of the coupled CN-P cycles in the land-coastal margin system in response to a sustained global temperature perturbation on terrestrial denitrification. Model results show that the nutrient-limited coastal margin is extremely sensitive to changes in the dissolved and particulate organic matter loading from land via the rivers. These results suggest that perturbations affecting the terrestrial denitrification flux are amplified rather than attenuated in the coastal margin. In a global warming scenario with enhanced terrestrial denitrification| the coastal margin becomes more autotrophic relative to its present heterotrophic status. In contrast| in the case of a cooling scenario with decreased denitrification fluxes on land| the coastal margin becomes more heterotrophic relative to its initial status. For the +10 degrees to -10 degrees C range of temperature perturbations simulated by our model| net ecosystem metabolism of the coastal margin varied by a factor of 34| from about +0.5 x 10(12) to -17 x 10(12) moles of carbon per year. It is evident that the coastal margin trophic status is principally governed by changes in the flux of organic matter from land. The effect of changes in the riverine flux of inorganic nutrients to the coastal ocean| which changes in the same direction as that of the riverine organic flux| is small compared to that of terrestrial organic matter loading. We argue that the effects of temperature change and of certain land-use activities| such as deforestation| are similar with respect to the nitrogen cycle in the coupled land-coastal margin system. Natural global temperature variations over the last 6000 years of Earth's history| including the relative warmth of the Holocene Climatic Optimum and the Medieval Warm Period and the coolness of the Little Ice Age| probably led to changes in denitrification fluxes on land and transport of organic matter and inorganic nutrients to the coastal oceans by rivers and groundwater. Pre-industrial anthropogenic activities on land probably enhanced the delivery of organic and inorganic nitrogen and organic matter to the oceans. These variations in the riverine flux led to continuous change in the trophic status of the global coastal margin and in the air-sea exchange of CO2. The global analysis provides some insight into the direction of change but does not provide quantitative estimates of the magnitude of change. However| there is little doubt that on a global scale| downstream reservoirs of shallow groundwater| rivers and coastal margins can be affected relatively rapidly by changes in terrestrial denitrification fluxes brought about by natural temperature variations and land-use activities. The land-coastal margin system must be viewed as an entity in considerations of global environmental change. 3928,1994,2,4,MODELING THE BEHAVIOR OF THE NORTHERN ANCHOVY| ENGRAULIS-MORDAX| AS A SCHOOLING PREDATOR EXPLOITING PATCHY PREY,Extensive data sets on the bioenergetics of the northern anchovy| Engraulis mordax| and the patchy food distribution in its natural habitat allow its foraging dynamics to be inferred by modeling using techniques from population biology and behavioral ecology. The behavioral model consistently predicts that E. mordax grows much more slowly than would be expected with a pure| net-energy intake rate maximization strategy. The reduced growth rates could result from the fish avoiding zooplankton patches| where they are under increased predation risk| by swimming slowly in the waters between zooplankton patches. The combinations of growth rates and daily instantaneous mortality rates generated by the behavioral model are internally consistent with a Lefkovitch matrix population model| which includes an early juvenile stage of a stable and stationary population. Several novel and testable predictions are made by the behavioral model| including: (1) anchovies swim very slowly between zooplankton patch encounters; (2) within a patch fish swim very rapidly while searching for prey; and (3) fish often leave zooplankton patches before totally filling their stomachs. Given these encouraging initial results| the behavioral modeling approach appears to be a valuable technique for examining how potential habitat changes due to global warming may affect fish behavior and populations. Several such scenarios are proposed and discussed. 3831,1994,4,4,MODELING WATER AND NITROGEN DYNAMICS ON CATCHMENT SCALE,This paper presents an attempt to integrate methods of landscape regionalization and already established model approaches which describe the soil water budget| the dynamics of soluble and adsorbed substances as well as the different processes of the soil nitrogen budget. This integration leads to the Catchment Related Water & Substance Simulation System (CWSS)| which gives the ability to carry out simulations for the area of small catchments. CWSS is a modular process-based system that simulates the soil water and ground water dynamics| surface runoff| soil heat budget and organic carbon and nitrogen transformation processes. It gives the ability to calculate water and substance budgets for a number of landscape cells| determined by the heterogeneity of soil conditions| elevation and landuse. Water and substance inputs into creeks| rivers and lakes concerning to the catchment area can be simulated with a high temporal resolution. There are many scientific and management applications| for which this system could be used. For example it could help address ecological issues like eutrophication| effects of global warming| water management and soil erosion. Methods of parameter estimation and procedures concerning the regional aspects of soil variability| elevation and landuse conditions are described. The combination with a geographical information system (GIS) and the deduction of input values from various data sets| which are available all over the country| are described. Some simulation results related to the catchment of Lake Belau (north Germany) will be discussed. In this area nitrate concentrations of ground water exceed the legal limit for drinking water (50 mg NO3/l) and a high degree of eutrophication characterizes the lake. 3813,1994,3,2,N2O EMISSIONS AT SOLID-WASTE DISPOSAL SITES IN OSAKA CITY,Nitrous oxide (N2O) is a trace gas contributing to stratospheric ozone depletion and global warming. Although a large quantity of information exists about N2O emissions from various ecosystems| this study was initiated to demonstrate the features of N2O emissions from sea-based waste disposal sites in Osaka City in relation to CH4 emissions. Average N2O emissions at an active landfill (S-Site) were several times higher than those at a closed landfill (N-Site). Average CH4 emissions were also much greater at the S-Site. Regarding the nature of N2O emissions| remarkable emissions often were observed with aerobic waste layers at the N-Site| suggesting almost inversely related N2O emissions with CH4 production at the N-Site. However| at the S-Site a few exceptionally high N2O emissions were noted in cases of high CH4 emissions. 3793,1994,5,4,NEW ATMOSPHERIC PCO(2) ESTIMATES FROM PALEOSOLS DURING THE LATE PALEOCENE EARLY EOCENE GLOBAL WARMING INTERVAL,The late Paleocene to early Eocene was one of the warmest intervals in Earth's history. Superimposed on this long-term warming was an abrupt short-term extreme warm event at or near the Paleocene/Eocene boundary and centered in the higher latitudes. This short-term climate warming was associated with a major benthic foraminiferal extinction and a dramatic 3-4 parts per thousand drop in the ocean's carbon isotopic composition. It has been suggested that the late Paleocene/early Eocene global warming was caused by an enhanced greenhouse effect associated with higher levels of atmospheric CO2 relative to present levels. We present carbon isotopic data from the co-existing paleosols organic matter and carbonates from a terrestrial sequence in the Paris Basin| France that contradict the notion that an increase in atmospheric CO2 level was the cause of extreme warming for this time interval. Atmospheric pCO(2) estimates for the Late Paleocene/early Eocene estimated from the terrestrial carbon isotopic record spanning the Paleocene/Eocene transition| are indistinguishable from each other and were generally between 300 and 700 ppm. 3795,1994,4,2,NEW SUNSHINE PROJECT AND PHOTOVOLTAIC DEVELOPMENT IN JAPAN,The global environmental consequences of CO2 discharge resulting from energy use are causing mounting concern regarding the sustainability of our development in the future. Japan successfully overcame two energy crisis in the 1970s despite the fragile nature of its energy structure and was able to maintain economic growth| resulting in a dramatic improvement in its industrial technology as a whole. Noteworthy is that such efforts were successful because they included such means as substituting an unconstrained production factor (technology) for a constrained production factor (energy) in a manner similar to an ecosystem. Given the two-directional nature of CO2 discharge and energy consumption| the experience of Japan can provide informative suggestions in response to current worldwide concerns regarding global warming due to CO2 discharge. However| Japan may now face the prospect of energy and environmental constraints again following the fall of international oil prices. In response| MITI established the New Sunshine Program (R&D program on Energy and Environmental Technologies) by integrating related R&D programs. A PV power generation system is one of the priority projects in the Program. 3890,1994,3,3,NITROUS-OXIDE AND GLOBAL WARMING,The climatic impact of nitrous oxide (N2O) emissions is calculated annually for the period 1900-2100| using a globally averaged computer model. Emissions of N2O have been increasing up to an estimated 12.7 Tg N/year in 1990 by human activities and global warming. If the current trends continue| emissions are estimated to be 25.7 Tg N/year by 2100| with fossil fuel use and human food production as major contributors. The resulting equilibrium temperature increase| 0.37-degrees-C| exceeds the forcing derived from climate goals that may be considered environmentally desirable. Limiting equilibrium warming to 0.1-degrees-C per decade would require anthropogenic-induced and warming-induced N2O emissions to be reduced by 80% relative to current trends and to be stabilised from 2050| so that 10.7 Tg N/year is emitted by 2100. To stabilise the current concentration or climate forcing of N2O| substantially larger cuts are needed. However| even in an optimistic scenario emissions keep increasing up to 14.4 Tg N/year by 2100. A major reason is the close connection between N2O emissions and human food production. Synthetic fertiliser use| land-use change and production of manure increase almost inevitably as the human population grows. Thus if global warming is to be limited to 0.1-degrees-C per decade it may be necessary to set emission reductions for other greenhouse gases relatively high to compensate for growth in climatic forcing by N2O. 3841,1994,4,3,NORTH-SOUTH DIFFERENCES| GLOBAL WARMING| AND THE GLOBAL SYSTEM,The questioning of the nineteenth century baseline for anthropogenic contributions to global warming is important for its role in a wider debate about the ''framing'' of this problem between the more-developed and less-developed countries of the world. An analysis of this debate raises such potentially important questions as: (1) How do historical/developmental differences among nations affect global warming? (2) How does the prior history of one nation affect the subsequent history of another with respect to global warming? And (3)| what are the consequences of the separation in time (and space) of the capacity to exacerbate versus mitigate global warming? The larger question underlying all of these is: What is the relationship between differences in national histories| the problem of global warming| and the development of a global system capable of addressing it? 3863,1994,2,3,OFFSETTING CHANGES IN BIOMASS ALLOCATION AND PHOTOSYNTHESIS IN PONDEROSA PINE (PINUS-PONDEROSA) IN RESPONSE TO CLIMATE-CHANGE,We examined the effect of climate on aboveground biomass allocation of ponderosa pine (Pinus ponderosa) by measuring trees in disjunct forest stands growing on the same substrate at high-elevation montane sites and low-elevation desert sites. Climatic differences between the sites were comparable to the difference between present and future climates of interior North America that is expected to result from a doubling of atmospheric CO2 concentration. Relative to the montane populations| the desert populations allocated a greater proportion of biomass to sapwood (functional xylem) at the expense of foliage. The leaf/sapwood area ratio and percent of aboveground biomass in sapwood for trees of the same height were 0.201 m2 cm-2 and 58% for montane trees and 0.104 m2 cm-2 and 71% for desert trees. In a phytotron experiment| increases in net photosynthesis and net assimilation rate for seedlings grown under future conditions of high CO2 and temperature were offset by a decrease in leaf area ratio. As was observed for large trees at different elevations| increased temperatures caused an increase in biomass allocation to stem in the phytotron seedlings. Thus| CO2- and temperature-driven shifts in biomass allocation negated the effect on growth of the CO2-driven increase in carbon assimilation rate. Our data from the controlled growth chamber and field experiments suggest that future climate conditions| including elevated atmospheric CO2| may not stimulate growth and productivity of ponderosa pine. 3922,1994,4,5,ON THE SCIENTIFIC BASIS FOR GLOBAL WARMING SCENARIOS,The scientific basis for current projections of significant warming due to enhanced minor greenhouse gases in the atmosphere is reviewed. Care is taken to distinguish the issue of changes in radiative forcing at the earth's surface from the issue of the climatic response to this forcing. With respect to the former| it is noted that the predicted forcing is| in fact| small (2 W m-2 at the surface for a doubling of CO2| or less than 1% of the absorbed solar flux). With respect to the latter| it is noted that predictions of significant warming are dependent on the presence of large positive feedbacks serving to amplify the response. The largest of these feedbacks in current models involves water vapor at upper levels in the troposphere. This feedback appears to be largely a model artifact| and evidence is presented that models may even have the wrong sign for this feedback. The possibility is examined that the response of climate to major volcanic eruptions may provide a test of the climate system's amplification. The basis for this possibility is the fact that the response delay of the ocean-atmosphere system is proportional to the system gain. 3817,1994,3,3,OPTIMAL CARBON EMISSIONS TRAJECTORIES WHEN DAMAGES DEPEND ON THE RATE OR LEVEL OF GLOBAL WARMING,In this paper we extend our earlier work with the Carbon Emissions Trajectory Assessment model (CETA) to consider a number of issues relating to the nature of optimal carbon emissions trajectories. We first explore model results when warming costs are associated with the rate of temperature rise| rather than with its level| as in our earlier work. We find that optimal trajectories are more strongly affected by the degree of non-linearity in the warming cost function than by whether the cost function is driven by the warming level or the warming rate. Next we briefly explore the implications of simple uncertainty and risk aversion for optimal emissions trajectories. We find that uncertainty and risk aversion cause optimal emissions trajectories to be somewhat lower| but that the effect is not noticeable in the near term and not dramatic in the long term; the long term effect on the shadow price of carbon is more marked| however. Finally| we experiment with scaling up the warming cost functions until optimal policies are approximately the same as a policy of stabilizing emissions at the 1990 level. Based on the results of this experiment| we conclude that damages would have to be very high to justify anything like a stabilization policy; and even in this case| a policy allowing intertemporal variation in emissions would be better. 3821,1994,3,4,OZONE DEPLETION AND GLOBAL WARMING POTENTIALS OF CF3I,Laboratory measurements of the infrared and near-ultraviolet absorption characteristics of CF3I (a potentially useful substitute for halons) are presented. Using these data together with a detailed photochemical model| it is shown that the lifetime of this gas in the sunlit atmosphere is less than a day. The chemistry of iodine in the stratosphere is evaluated| and it is shown that any iodine that reaches the stratosphere will be very effective for ozone destruction there. However| the extremely short lifetime of CF3I greatly limits its transport to the stratosphere when released at the surface| especially at midlatitudes| and the total anthropogenic surface release of CF3I is likely to be far less than that of natural iodocarbons such as CH3I on a global basis. It is highly Probable that the steady-state ozone depletion potential (ODP) of CF3I for surface releases is less than 0.008 and more likely below 0.0001. Measured infrared absorption data are also combined with the lifetime to show that the 20-year global warming potential (GWP) of this gas is likely to be very small| less than 5. Therefore this study suggests that neither the ODP nor the GWP of this gas represent significant obstacles to its use as a replacement for halons. 3913,1994,5,2,PALAEO-PERSPECTIVES - REDUCING UNCERTAINTIES IN GLOBAL CHANGE,Information on the history of the Earth system is an important element in assessing global change. Analysis of air trapped in natural ice has provided data on the pre-industrial concentrations of greenhouse gases like CO2 and CH4| and their recent increase-and has shown that the latter effect can be unequivocally attributed to human activities. Such data also provide the basis for estimating that the present anthropogenic greenhouse forcing is 2.5 W/m2. Records for the last 150 000 years show the variation of Earth system parameters during one and a half glacial cycles. The presence of the frequencies of the orbital forcing indicates that changes in these parameters are the main cause of the glacial-interglacial cycles. The concentrations of CO2 and CH| vary in parallel with global temperature; whilst CH4 closely follows the climatic variations| the relationship of CO2 with climate is much more complicated. Temperature in the Northern and the Southern Hemispheres varied closely in phase during a glacial cycle. In the Northern Hemisphere| changes in albedo (due to changes in ocean ice cover) are thought to amplify the orbital forcing; the Southern Hemisphere climate may have been forced to follow the climate of the Northern Hemisphere due to the changing greenhouse forcing. From the last glacial maximum to the present interglacial the greenhouse forcing increased by ca. 2.5 W/m2. In addition to the smoothed long-term climatic trends over a glacial cycle (known from ocean sediment records)| high resolution records (from ice core and lake sediments) reveal rapid climatic changes by several degrees within a decade or so. The relatively stable climate during the present interglacial is exceptional; previously| the climate was much more variable| probably due to changes in deep water formation in the North Atlantic. Recent ice core results| indicate that this instability may also have occurred during the last interglacial| when it was around 2-degrees-C warmer than at present| raising the possibility that the climate could become unstable if human-induced global warming occurs. Such unexpected results show the complexity of the Earth system and the need for an appraisal of our understanding of its behavior. 3873,1994,3,2,PASSENGER CAR GLOBAL WARMING POTENTIAL - CURRENT AND PROJECTED LEVELS IN THE UK,This paper presents the results of a new analysis of the global warming potential of emissions from passenger cars in the UK. Projections of future emissions are combined with GWPs to present a picture of the overall potential of future car transport emissions to affect the global climate. The projections from this modelling exercise point to the fact that the car transport sector will not be able to meet the international target of returning emissions of greenhouse gases to their 1990 levels by 2000. Technological improvements will help to keep in check the total warming impact of car transport in the near future by reducing non-carbon dioxide emissions. However| eventually demand increases will overcome this benefit unless further improvements| particularly in CO2 emissions| can be achieved. This suggests a need for prompt introduction of longer-term measures to manage demand and increase trip efficiency. The results of our sensitivity analysis suggest that more work to better determine nitrous oxide emissions factors should be given priority| that increasing diesel market share has little impact| and that the uncertainties over actual GWP values do not appear to have a significant impact on the total warming potential of passenger car emissions. 2617,1994,2,4,PEATLANDS AND GLOBAL CLIMATE-CHANGE - INSIGHTS FROM COMPARATIVE-STUDIES OF SITES SITUATED ALONG A LATITUDINAL GRADIENT,Sphagnum-dominated peatland ecosystems that are structurally and functionally similar to their boreal and subarctic counterparts are found as far south as West Virginia. Completed| ongoing| and preliminary studies conducted at Bog Run Bog| WV| Bog Lake Bog| MN| and Wetland 307 of the Experimental Lakes Area| Ontario have included 1) a reciprocal transplant of dominant hummock and hollow Sphagnum species| examining growth in length| 2) a reciprocal transplant of peat| with periodic retrieval of transplanted samples and analysis of CO2 and CH4 production under anoxic and oxic conditions at held temperature and at 22 degrees C| 3) C-14-labeling of vegetation in hollow| hummock| and shrub plots| following the fate of a single day's photosynthetic fixation through aboveground and belowground components over time| and 4) a preliminary analysis of C-13 ratios in peat and of the CH4 that is produced and emitted. Collectively| these studies provide support for the premise that comparative studies of northern (cooler climate) and southern (warmer climate) peatland sites may provide insights into potential functional changes in boreal peatlands under predicted scenarios of global climate change.
3816,1994,3,4,PENTANE BLOWN POLYURETHANE RIGID FOAMS FOR CONSTRUCTION,Pentane as a blowing agent for polyurethane rigid foam has gained easy access to the European market. Initially introduced in the Double Conveyor Belt (DCB) production of laminate boards| its use spread to the introduction of metal sandwich panels and slabstock foam. Recently cyclopentane has been introduced as a blowing agent in the production of polyurethane foam for home appliances and construction. Today several plants run a full scale production of pentane blown polyurethane rigid foam. Pentane combines advantageous physical and technical properties with good environmental data. Being halogen free| pentane is safe for the ozone layer| and its contribution to the Global Warming Potential (GWP) is negligible. The processing of pentane blown polyurethane rigid foam systems is determined by the inflammability of the blowing agent and its limited solubility in the raw materials. Even though the fire risk can be controlled by safety measures and devices| pentane is not a simple replacement for CFC-11 as a polyurethane blowing agent. Its use requires major development work. The physical properties of pentane blown foams match those of CFC-11 blown ones. The initial thermal conductivity is higher. Nevertheless| the aging characteristics of the foams are excellent and at least equivalent to those of CFC-11 blown foams. Aging tests indicate that pentane remains in the cell gas as long as CFC-11. The production of highly flame retarded pentane blown PUR and PIR foams is possible. Small and large scale fire tests of pentane blown foams gave no indication of a higher fire risk than CFC-11 blown foams. The paper deals with the development| production and properties of pentane blown polyurethane rigid foam for construction. 2655,1994,2,4,POPULATION DIFFERENTIATION IN LOCOMOTOR PERFORMANCE AND THE POTENTIAL RESPONSE OF A TERRESTRIAL ORGANISM TO GLOBAL ENVIRONMENTAL-CHANGE,Models of global climate change predict an increase in the mean surface temperature between 1.5 degrees and 4.5 degrees C by the middle of the next century. Even a moderate increase of 3 degrees C is Likely to result in a shift in the distribution of North American habitat types and vegetational associations| either in latitude or elevation or both. The challenge to Conservation Biology is to predict the responses of terrestrial organisms to the expected alteration in habitats and ecosystems. Recent biophysical models have been expanded to demonstrate the intimate associations between the thermal environment| organismal physiology and ecology. Thus| the expected turnover in habitats may have a profound influence on the distribution of organisms. I describe one possible approach that couples temporal and spatial variation in an ecologically relevant physiological trait| locomotory performance| in a widespread species of lizard| Urosaurus ornatus| to predict the expected response of species to global change. Estimates of maximum velocity and endurance capacity were obtained from 16 populations throughout the range of U. ornatus. Information on spatial variation was supplemented with data on temporal variation spanning an eight year period from a single reference population. I used these data to address two questions: 1) is there an association between locomotory performance and the expected habitat changes predicted from global climate models and 2) is there sufficient variation within a population to respond to habitat modification. Populations of U. ornatus varied significantly in sprint speed and stamina. Several environmental factors expected to correlate with global climate change were evaluated using the patterns of variation in locomotor performance. Results from this study suggest that high elevation populations found in ponderosa pine forests should be most susceptible to changes in climate. Within-population variation was found to span the range of variation seen among populations and was sensitive to temporal variation in climatic conditions. Given the expected and rapid change in environments| small| ectothermic| terrestrial species may not have the ability to modify their geographic distribution. However| the results presented here suggest that only certain populations are at risk; yet the evolutionary response of the population may be long relative to the rate of environment change.
2633,1994,2,2,POSSIBLE IMPLICATIONS OF GLOBAL CLIMATE-CHANGE ON GLOBAL LIGHTNING DISTRIBUTIONS AND FREQUENCIES,The Goddard Institute for Space Studies (GISS) general circulation model (GCM) is used to study the possible implications of past and future climate change on global lightning frequencies. Two climate change experiments were conducted: one for a 2 X CO2 climate (representing a 4.2-degrees-C global warming) and one for a 2% decrease in the solar constant (representing a 5.9-degrees-C global cooling). The results suggest a 30% increase in global lightning activity for the warmer climate and a 24% decrease in global lightning activity for the colder climate. This implies an approximate 5-6% change in global lightning frequencies for every 1-degrees-C global warming/cooling. Both intracloud and cloud-to-ground frequencies are modeled| with cloud-to-ground lightning frequencies showing larger sensitivity to climate change than intracloud frequencies. The magnitude of the modeled lightning changes depends on season| location| and even time of day.
3830,1994,2,4,POTENTIAL DISTRIBUTION OF METHANE HYDRATES IN THE WORLDS OCEANS,Estimates of the magnitudes and spatial distribution of potential oceanic methane hydrate reservoirs have been made from pressure-temperature phase relations and a plausible range of thermal gradients| sediment porosities| and pore fillings taken from published sources| based on two major theories of gas hydrate formation (1) in situ bacterial production and (2) pore fluid expulsion models. The implications of these two models on eventual atmospheric methane release| due to global warming| are briefly examined. The calculated range of methane volumes in oceanic gas hydrates is 26.4 to 139.1 x 10(15) m(3)| with the most likely value on the lower end of this range. The results for the bacterial model show a preferential distribution of hydrates at mid- to high latitudes| with an equatorial enhancement in the case of the fluid migration model. The latter model also generates a deeper and thicker hydrate stability zone at most latitudes than does the former. Preliminary results suggest that the hydrate distribution predicted by the fluid migration model may be more consistent with observations. However| this preliminary finding is based on a very limited sample size| and there are high uncertainties in the assumptions. The volume of methane hydrate within the uppermost 1 m of the hydrate stability zone and within 1 degrees-2 degrees C of the equilibrium curve| assuming in situ bacterial generation| is 0.93-6.32 x 10(12) m(3)| or 0.0035-0.012% of the maximal estimated hydrate reservoir. Nevertheless this volume| if released uniformly over the next 100 years| is comparable to current CH4 release rates for several important CH4 sources. Corresponding CH4 volumes calculated using the fluid migration model are nearly 2 orders of magnitude lower. 3882,1994,2,4,POTENTIAL EFFECT OF GLOBAL WARMING ON MOSQUITO-BORNE ARBOVIRUSES,If global warming curs in California| daily mean temperatures may increase by 3 to 5-degrees-C| precipitation patterns will change| and sea level may rise 1 m. Studies were done on effect of temperature changes on survival of Culex tarsalis Coquillett| the primary vector of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses| in two regions where temperatures differed by 5-degrees-C. Daily mortality of adult vectors increased by 1% for each 1-degrees-C increase in temperature. At 25-degrees-C| only 5% of Cx. tarsalis survived for 8 or more days| the time required for extrinsic incubation of these viruses. Extrinsic incubation times for these viruses shortened when temperatures were increased from 18 to 25-degrees-C. WEE virus infection was modulated and transmission decreased at 32-degrees-C. If temperatures in the warmer region increase by 5-degrees-C| WEE virus may disappear and SLE virus would persist. In the cooler region| a 5-degrees-C increase would decrease vector survivorship and virus activity in midsummer. In North America| epidemics of WEE have prevailed above a 21-degrees-C isotherm and those of SLE below this isotherm. With global warming| epidemics of these viruses could extend into currently unreceptive northern areas. WEE virus would disappear from more southern regions. Geographic distribution of vector| human| and animal populations could be altered. North America could become more receptor to invasion by tropical vectors and diseases. 3835,1994,5,4,PREHISTORIC ANTHROPOGENIC WILDLAND BURNING BY HUNTER-GATHERER SOCIETIES IN THE TEMPERATE REGIONS - A NET SOURCE| SINK| OR NEUTRAL TO THE GLOBAL CARBON BUDGET,There is a need for more intensive multi-disciplinary study of prehistoric ''hunter-gatherer'' burning patterns in temperate regions. California is presented as a case study to demonstrate how powerful| effective| and widely employed fire was in the native repertoire for directly manipulating the wildland environment. It is highly likely that the magnitude of burning in other temperate regions as well as in California| has been underestimated by anthropologists. A methodological approach to better define the broad outlines of anthropogenic wildland burning patterns in various regions of North America| at the point of Euro-American contact| is put forth. Regional studies which revaluate: the extent to which Native American tribes were an important ecological force in shaping the biotic and physical environment| will have profound implications for contemporary environmental policies to reduce the threat of global warming. It is suggested that physical| social| and biological scientists work together to examine global warming in a broader historical context to include temperate wildland burning by prehistoric peoples and explore its contribution as a net source| sink| or neutral Lo the global carbon budget. 3892,1994,2,4,QUANTIFYING GLOBAL WARMING FROM THE RETREAT OF GLACIERS,Records of glacier fluctuations compiled by the World Glacier Monitoring Service can be used to derive an independent estimate of global warming during the last 100 years. Records of different glaciers are made comparable by a two-step scaling procedure: one allowing for differences in glacier geometry| the other for differences in climate sensitivity. The retreat of glaciers during the last 100 years appears to be coherent over the globe. On the basis of modeling of the climate sensitivity of glaciers| the observed glacier retreat can be explained by a linear warming trend of 0.66 kelvin per century. 3911,1994,2,4,RAGWEEDS (AMBROSIA L) IN BRITAIN,The occurrence and ecology of three species of Ragweed (Ambrosia L.) in Britain is described. Ambrosia artemisiifolia L. is the commonest species and is most often introduced with bird seed| but does not persist probably due to climate limitation of seed production and germination. A. psilostachya DC| is rarely established in sandy places. A. trifida L. is an uncommon introduction which also does not persist. Ragweed pollen was regularly recorded in Britain in 1992. Under conditions of global warming| it is likely that A. artemisiifolia will become established in Britain and could cause widespread hay fever. 3810,1994,3,4,REACTIVE ION ETCHING OF PBZR1-XTIXO3 AND RUO2 FILMS BY ENVIRONMENTALLY SAFE GASES,A new process for the reactive ion etching (RIE) of both PbZr1-xTixO3 (PZT) thin films and RuO2 electrodes is presented| employing etching gases with low ozone depletion potential (ODP) and global warming potential (GWP). The etching process has been investigated as a function of etching time| discharge power density| chamber pressure| and additive gas. Etch rates were in the range of 250-650 Angstrom/min and 100-400 Angstrom/min for PZT and RuO2| respectively. A large etch selectivity between PZT and RuO2 was optimized. Etched surfaces exhibited smooth morphologies. Furthermore| the ferroelectric properties of PZT were not altered significantly by the etching process. A surface residue containing Cl and F was found after etching| but this organic substance was totally removed by an after-etch bake. In addition| the etched profile of the PZT films was studied through SEM. 2628,1994,4,2,RECENT AND FUTURE CLIMATE-CHANGE IN EAST-ASIA,The signing of the UN Framework Convention on Climate Change in Rio de Janeiro in June 1992 by 160 nations has firmly identified global climate change due to human pollution as a pressing global environmental concern. Among the responsibilities that the nations which ratify the Convention will have are the drawing up of inventories of greenhouse gas sources and sinks and the formulation of national strategies to respond to climate change through adaptive and/or preventive measures. One requirement for identifying appropriate response strategies will be the undertaking of regional assessments of climate change and its associated impacts. This paper is concerned with climate change in the East Asian region| both over the last 100 years (using instrumental data) and also for the next 100 years (using results from climate model experiments). The juxtaposing of these two analyses| historical and future| enables a better interpretation of the significance of regional climate change to be made. Instrumental temperature and precipitation data for the East Asian region are analysed and compared with the observed global-scale trends in these two variables. Although the region has undoubtedly warmed over the last century| understanding the exact causes of the complex seasonal| diurnal| and spatial dimensions of this warming is difficult. We examine the role of increasing urbanization in inducing rising temperatures and suggest that| although substantial| urban warming cannot account for all of the observed temperature change. The paper also illustrates a flexible composite-model approach to regional climate change scenario construction that avoids the need for multiple transient GCM experiments| which can explicitly incorporate the effects of intermodel uncertainty| and is flexible enough to incorporate new scientific findings and results from new GCM experiments. The scenario presented here suggests that by 2050| mean conditions are expected to be warmer than the extremely warm seasonal anomalies that occurred during the most recent decade in East Asia. Precipitation is estimated to rise over most of the region in all seasons| although the uncertainty range attached to this estimate is much wider than for temperature.
2644,1994,4,4,REGIONAL CLIMATES IN THE GISS GENERAL-CIRCULATION MODEL - SURFACE AIR-TEMPERATURE,One of the more viable research techniques into global climate change for the purpose of understanding the consequent environmental impacts is based on the use of general circulation models (GCMs). However| GCMs are currently unable to reliably predict the regional climate change resulting from global warming| and it is at the regional scale that predictions are required for understanding human and environmental responses. Regional climates in the extratropics are in large part governed by the synoptic-scale circulation and the feasibility of using this interscale relationship is explored to provide a way of moving to grid cell and sub-grid cell scales in the model. The relationships between the daily circulation systems and surface air temperature for points across the continental United States are first developed in a quantitative form using a multivariate index based on principal components analysis (PCA) of the surface circulation. These relationships are then validated by predicting daily temperatures using observed circulation and comparing the predicted values with the observed temperatures. The relationships predict surface temperature accurately over the major portion of the country in winter| and for half the country in summer. These relationships are then applied to the surface synoptic circulation of the Goddard Institute for Space Studies GCM control run| and a set of surface grid cell temperatures are generated. These temperatures| based on the larger-scale validated circulation| may now be used with greater confidence at the regional scale. The generated temperatures are compared to those of the model and show that the model has regional errors of up to 10-degrees-C in individual grid cells.
3850,1994,3,3,RENEWABLE ALTERNATIVE FUELS - ALCOHOL PRODUCTION FROM LIGNOCELLULOSIC BIOMASS,Advances in renewable alternative biomass-based fuel technologies make their commercialization likely within a decade. Substituting fuels derived from biomass for fossil fuels can reduce dependence on petroleum use| improve air quality| mitigate global warming| and strengthen a weak farm economy. Implementation of the Clean Air Act Amendments of 1990 increased the oxygenate content in gasoline| providing greater market opportunities for alcohols-as direct blends and to produce ethers such as ETBE and MTBE. Alcohol production from lignocellulosic biomass is promising| leading to renewable| alternative transportation fuels that are projected to be competitive as pure fuels with fuels derived from petroleum at $20-$25/bbl ($0.13-$0.16/liter) within the next 5 to 10 years. However| the timeframe for deployment depends not only on the development of technologies| but also on the active involvement of appropriate industries. Industrial partnerships have been formed| and commericalization strategy is well under way; process development units at the pilot scale are both operating and under construction in the United States. Alliances between industry and the government include agreements to proceed with scale-up to engineering development units and eventually to commercial-scale plants. 3888,1994,3,4,REPORTING EMISSIONS OF GREENHOUSE GASES IN CANADA,Non-carbon dioxide greenhouse gases are considered in ''Canada's National Report on Climate Change: Actions to Meet Commitments Under the United Nations Framework Convention on Climate Change''. By including all major greenhouse gases and their anthropogenic sources and sinks using best available science| the Report provides a practical illustration of the ''comprehensive approach'' policy to implementing the Convention's requirements. In addition to carbon dioxide emissions from fossil fuel combustion| the Report includes information on other sources and sinks for carbon dioxide| and for methane and nitrous oxide. Other gases considered include polyflourocarbons| hydroflourocarbons| and the primary tropospheric ozone precursors| nitrogen oxides and volatile organic compounds. Current Global Warming Potential indices are used to compare and integrate the best estimates of climate change impacts of the major greenhouse gases. The presentation of emission data is intended to be transparent and comparable. The relative quality of the data for various gases and sources is indicated. The existence of environmental| economic| and other benefits to limiting emissions of all greenhouse gases| in addition to carbon dioxide| should be recognized. Continuing assessments and actions on non-carbon dioxide greenhouse gas emissions| both nationally and internationally| are suggested. 3812,1994,4,3,RESERVOIR TIMESCALES FOR ANTHROPOGENIC CO2 IN THE ATMOSPHERE,Non-steady state timescales are complicated and their application to specific geophysical systems requires a common theoretical foundation. We first extend reservoir theory by quantifying the difference between turnover time and transit time (or residence time) for time-dependent systems under any mixing conditions. We explicitly demonstrate the errors which result from assuming these timescales are equal| which is only true at steady state. We also derive a new response function which allows the calculation of age distributions and timescales for well-mixed reservoirs away from steady state| and differentiate between timescales based on gross and net fluxes. These theoretical results are particularly important to tracer-calibrated ''box models'' currently used to study the carbon cycle| which usually approximate reservoirs as well-mixed. We then apply the results to the important case of anthropogenic CO2 in the atmosphere| since timescales describing its behavior are commonly used but ambiguously defined. All relevant timescales| including lifetime| transit time| and adjustment time| are precisely defined and calculated from data and models. Apparent discrepancies between the current| empirically determined turnover time of 30-60 years and longer model-derived estimates of expected lifetime and adjustment time are explained within this theoretical framework. We also discuss the results in light of policy issues related to global warming| in particular since any comparisons of the ''lifetimes'' of different greenhouse gases (CO2| CH4| N2O| CFC's etc.) must use a consistent definition to be meaningful. 2643,1994,2,4,RESPONSES OF RESPIRATION TO INCREASING ATMOSPHERIC CARBON-DIOXIDE CONCENTRATIONS,It has been recently recognized that increases in carbon dioxide concentration such as are anticipated for the earth's atmosphere in the next century often reduce plant respiration. There can be both a short-term reversible effect of unknown cause| and long-term acclimation| which may reflect the synthesis and maintenance of less metabolically expensive materials in plants grown at elevated carbon dioxide concentrations. Because respiration provides energy and carbon intermediates for growth and maintenance| reductions in respiration by increasing carbon dioxide concentrations may have effects on physiology beyond an improvement in plant carbon balance. As atmospheric carbon dioxide concentration increases| reduced respiration could be as important as increased photosynthesis in improving the ability of terrestrial vegetation to act as a sink for carbon| but it could also have other consequences.
3851,1994,2,3,RESPONSES OF TRACE GAS FLUXES AND N AVAILABILITY TO EXPERIMENTALLY ELEVATED SOIL TEMPERATURES,We are conducting a field study to determine the long-term response of belowground processes to elevated soil temperatures in a mixed deciduous forest. We established 18 experimental plots and randomly assigned them to one of three treatments in six blocks. The treatments are: (1) heated plots in which the soil temperature is raised 5-degrees-C above ambient using buried heating cables; (2) disturbance control plots (cables but no heat); and (3) undisturbed control plots (no cables and no heat). In each plot we measured indexes of N availability| the concentration of N in soil solutions leaching below the rooting zone| and trace gas emissions (CO2| N2O| and CH4). In this paper we present results from the first 6 mo of this study. The daily average efflux of CO2 increased exponentially with increasing soil temperature and decreased linearly with increasing soil moisture. A linear regression of temperature and the natural logarithm of CO2 flux explained 92% of the variability. A linear regression of soil moisture and CO2 flux could explain only 44% of the variability. The relationship between soil temperature and CO2 flux is in good agreement with the Arrhenius equation. For these CO2 flux data| the activation energy was 63 kJ/mol and the Q10 was 2.5. The daily average uptake of CH| increased linearly with increasing soil temperatures and decreased linearly with increasing soil moisture. Linear regression could explain 46% of the variability in the relationship between temperature and CH4 uptake and 49% of the variability in the relationship between soil moisture and CH4 uptake. We predicted the annual CO2 flux from our study site in 1991 using two empirical relationships: the relationship between air temperature and soil temperature| and the relationship between soil temperature and CO2 flux. We estimate that the annual CO2-C flux in 1991 was 712 g/m2 from unheated soil and 1250 g/m2 from heated soil. By elevating the soil temperature 5-degrees-C above ambient| we estimate that an additional carbon flux of 538 g.m-2.yr-1 was released from the soil as CO2. 3866,1994,3,3,RESULTS AND FULL FUEL-CYCLE STUDY PLANS FROM THE IEA GREENHOUSE-GAS RESEARCH-AND-DEVELOPMENT PROGRAM,Fourteen countries have signed an agreement to take part in an initial three-year programme of research and development aimed at potential mitigation techniques in response to the issue of global warming. Formed under the aegis of the International Energy Agency (IEA)| the programme brings together those countries interested in establishing the techniques| costs| and environmental consequences of removing CO2 and other greenhouse gases from fossil fuel-based power station flue gases and storing or otherwise disposing of them. The programme has evaluated many fossil fuel power generation options| with the technologies required for CO2 removal. Using the technical and economic results from these studies the programme has recently commenced a detailed specification for a series of full scale 'full fuel cycle' studies. The programme will culminate in proposals aimed at demonstration facilities should any of the full fuel cycle technologies show sufficient promise. In addition| the programme could be expanded to look in more detail at CO2 disposal options and the question of methane and its contribution to global warming. The project structure and work programme to date are described in outline and a summary of the results to date is given| with an overview of all of the technologies involved. 3883,1994,3,2,RICE PADDIES AS A METHANE SOURCE,Rice fields are considered to be among the highest sources of atmospheric methane| an important source of global warming. In order to meet the projected rice needs of the increasing world population| it is estimated that the annual world's rough rice production must increase to 760 million tons (a 65% increase) in the next 30 years. This will increase methane emissions from rice-fields if current technologies are kept. Methane emissions from ricefields are affected by climate| water regime| soil properties| and various cultural practices like irrigation and drainage| organic amendments| fertilization| and rice cultivars. Irrigated rice comprises 50% of the world-harvested rice area and contributes 70% to total rice production. Because of assured flooding during the growing period it is the primary source of methane. Rainfed rice emits less methane due to periods of droughts. Upland rice| being never flooded for a significant period of time| is not a significant source of methane. There is great potential to develop 'no regret' mitigation options that are in accordance with increasing rice production. 3941,1994,4,4,RITE - RESEARCH-INSTITUTE-OF-INNOVATIVE-TECHNOLOGY-FOR-THE-EARTH,The United Nations Conference on Environment and Development held in Rio de Janeiro in 1992| stimulated many national and international research programmes designed to control pollution and counter global warming. In Japan| these problems had already been given top-level consideration since 1989 and this led to the foundation of the Research Institute of Innovative Technology for the Earth (RITE) in Kansai Science City: it was formally opened last year. This article| by its Director-General| reviews its policy and the research programmes already under way. 2632,1994,2,4,ROLE OF PLANTS AND GLOBAL CLIMATE CHANGES IN SOIL EVOLUTION,Plants of the modern ecosystem influence humous content mainly to a depth of 20 cm. Therefore any climate changes that lead to succession changes of the ecosystem lead to a change in the humous content only in that layer. In deeper horizons due to global climate change| either the former humous state will be preserved or the humous reserves will diminish| which is related to mineralization of the humus or to gleying. Global climate changes also lead to a change in the water regime| which will facilitate peat accumulation (in the case of submersion) and decomposition with a more intensive water demand.
3923,1994,5,3,SAND SEA HISTORY OF THE TAKLIMAKAN FOR THE PAST 30|000 YEARS,A series of absolute dates for surface sediments in the Taklimakan Desert| reveals the evolution of aeolian processes over the past 30|000 years. Sandy materials from flood plains and palaeo-lacustrine plains through wind erosion are the main sources of the desert. Cold air intrusions from the northeast of the Tarim Basin are the main form of aeolian motivation. During the past 30|000 years| an arid climate has dominated the desert. However| sand sources and wind conditions affected by ice| snow cover| glacial meltwater and lower evaporation as well as more stable air conditions during very cold periods may have led to temporary decreases in aeolian actions. In contrast with other Chinese deserts| the evolution of the Taklimakan Desert has seen alternating periods of hot| arid| strong aeolian action and cold| relatively humid| weak aeolian action in response to global climate changes. It is predicted that desertification will continue due to the effects of global warming. 3867,1994,4,4,SCENARIOS FOR HALOCARBON EMISSIONS IN FINLAND AND ESTIMATES OF THEIR IMPACT ON GLOBAL WARMING AND CHLORINE LOADING IN THE STRATOSPHERE,Finnish halocarbon (CFC| HCFC and HFC) emissions and their impact on global warming and chlorine loading in the stratosphere have been estimated. CFC consumption is estimated to have begun in the 1960s in Finland. CFCs deplete ozone and are therefore being phased out. In Finland| the deadline is the year 1995. The total Finnish CFC consumption during 1960-1994 is estimated to be about 70 000 tonnes. The yearly consumption has been| at most| about 3000 tonnes.
CFCs will be partly substituted by HCFCs and HFCs. The yearly HCFC consumption has been around 300 tonnes since the mid 1980s. HFCs are new products and their use has been minor. Both HCFC and HFC consumption is assumed to increase. HCFCs will be gradually phased out between 1996 and 2030 because they also deplete ozone. No restrictions are planned for HFCs.
CFC emissions are evaluated in two scenarios. In the base scenario| all the consumed amount is expected to be released to the atmosphere. In the recovery scenario| 75% of the amount now stored in equipment and products (about 10 000 tonnes) is assumed to be recovered. Even if consumption is phased out in 1994| emissions continue until the next century.
3916,1994,2,4,SEASONAL VARIABILITY IN PARTICLE SEDIMENTATION UNDER PERMANENT ICE COVER IN THE ARCTIC-OCEAN,A study at 79 degrees N over the polar continental shelf off Ellef Ringes Island in 1989-1990 provided year-round measurements of particulate matter sedimentation in a permanently ice covered region of the Arctic Ocean. Mean annual Aux rates of mass (1.1 g m(-2))| organic carbon (134 mg m(-2))| nitrogen (24 mg m(-2))| chlorophyll a (3 mg m(-2)) and biogenic silicon (II mg m(-2)) were determined by deployment of two sediment traps from the Canadian Ice Island at a water depth of 100 m. High flues of mass| biogenic silicon and inorganic matter occurred between July and September during the melt-water runoff. Maximum sedimentation of organic matter and chlorophyll a occurred in August and September when centric diatoms and zooplankton fecal pellets were numerous in samples. Between February and June| when mass flues were low| settled particles were organically rich with low carbon:nitrogen ratios (4-8) in contrast to higher values (6-12) during the melt-water period. Mineralogy showed that chlorite| mica| illite and quartz were abundant in settled particles collected in August| October and December. Similar minerals| thought to be supplied as small particles by eolian transport| are present in ice cores and cryoconites on the Ice Island. The observations provide data for assessing future changes in production and particle export for this ice-covered region of the Arctic Ocean that may be altered due to global warming and related changes in ice cover. 3829,1994,2,2,SIMPLE GLOBAL CARBON MODEL - THE ATMOSPHERE-TERRESTRIAL BIOSPHERE-OCEAN INTERACTION,A simple global carbon model has been developed for scenario analysis| and research needs prioritization. CO2 fertilization and temperature effects are included in the terrestrial biosphere compartment| and the ocean compartment includes inorganic chemistry which| with ocean water circulation| enables the calculation of time-variable oceanic carbon uptake. Model-derived Q(10) values (the increasing late for every 10 degrees C increase of temperature) are 1.37 for land biota photosynthesis| 1.89 for land biota respiration| and 1.95 for soil respiration| and feedback temperature is set at 0.01 degrees C/ppm of CO2. These could be the important parameters controlling the carbon cycle in potential global warming scenarios. Scenario analysis| together with sensitivity analysis of temperature feedback| suggests that if CO2 emissions from fossil fuel combustion continue at the present increasing rate of similar to 1.5% per year| a CO2 doubling (to 560 ppm) will appear in year 2060. Global warming would be responsible for 40 Gt as carbon (Gt C) accumulation in the land biota| 88 Gt C depletion from the soil carbon| a 7 Gt C accumulation in the oceans| and a 19 ppm increase in atmospheric CO2. The ocean buffering capacity to take up the excess CO2 will decrease with the increasing atmospheric CO2 concentration. . 3874,1994,2,4,SIMULATED CLIMATE-CHANGE - A FIELD MANIPULATION STUDY OF POLAR MICROARTHROPOD COMMUNITY RESPONSE TO GLOBAL WARMING,Passive cloches were deployed at three altitudinally distinct sites on Signy Island| maritime Antarctica| to investigate the effect of ameliorated thermal environment upon fellfield microarthropod communities. Temperature was monitored at 1.5 m height| at ground surface level| and at 5 cm depth in cloche and control plots. During summer (December - March)| cloches elevated monthly mean temperatures by up to 2.46-degrees-C at the soil surface and 2.20-degrees-C at 5 cm depth. Integrated air temperatures over consecutive 10 d periods were up to 4.65-degrees-C warmer in cloches than controls. During winter (April - November)| snow cover of the fellfield sites buffered temperature variation and reduced the treatment effect. After eight years of these manipulations| sampling of the upper 50 mm of soil revealed consistently greater microarthropod populations within cloches than in controls (treatment effect: p < 0.05). Maximum difference occurred at high altitude where thermal amelioration was greatest (site effect: p < 0.05). Cloche populations of the numerically dominant collembolan Cryptopygus antarcticus Willem contained an increased proportion of small (length < 750 mum) individuals. No species new to Signy Island were recorded. Relating these microarthropod populations to the ameliorated thermal environment suggests that Antarctic invertebrate communities may respond to global warming| as predicted by global circulation models| with an increase in abundance with little increase in diversity. However| this response could be indirect| the intermediate controlling factor being the percentage cover of the soil surface by vegetation| itself a function of climate change. 2624,1994,2,4,SIMULATING CHANGES IN GLOBAL LAND-COVER AS AFFECTED BY ECONOMIC AND CLIMATIC FACTORS,This paper describes two global models: (1) an Agricultural Demand Model which is used to compute the consumption and demand for commodities that define land use in 13 world regions; and| (2) a Land Cover Model| which simulates changes in land cover on a global terrestrial grid (0.5(0) latitude by 0.5(0) longitude) resulting from economic and climatic factors. Both are part of the IMAGE 2.0 model of global climate change. The models have been calibrated and tested with regional data from 1970-1990. The Agricultural Demand Model can approximate the observed trend in commodity consumption and the Land Cover Model simulates the total amount of land converted within 13 world regions during this period. Some degree of the spatial variability of deforestation has also been captured by the simulation. Applying the model to a ''Conventional Wisdom'' scenario showed that future trends of land conversions could be strikingly different on different continents even though a consistent scenario (IS92a from the IPCC) was used for assumptions about economic growth and population. Sensitivity analysis indicated that future land cover patterns are especially sensitive to assumed technological improvements in crop yield and computed changes in agricultural demand.
3820,1994,4,4,SIMULATIONS OF ATMOSPHERIC VARIABILITY INDUCED BY SEA-SURFACE TEMPERATURES AND IMPLICATIONS FOR GLOBAL WARMING,An atmospheric general circulation model was forced with observed interannual changes in the global sea surface temperatures (SSTs) for the period 1982 to 1993. The simulated seasonal surface air temperature patterns over land areas closely resemble the observed. Over most of the globe| the patterns also resemble those associated with El Nino events and are also reproduced in simulations with weak warm tropical SSTs near the date line. An exception is northern Asia| where the mechanisms for the observed warming are unclear. The results suggest that enhanced air-sea interactions resulting from recent| more persistent warm oceanic conditions in the tropics contributed to the observed global warming trend during this period. 3889,1994,4,4,SOIL PROCESSES AND CHEMICAL-TRANSPORT - SOIL DEGASSING OF C-14 DIOXIDE - RATES AND FACTORS,Soil air normally contains elevated levels of CO2 relative to the atmosphere. The primary source of soil C is plant-root and microbial respiration. The exchange of soil and atmospheric CO2 is important to many environmental concerns| such as acid rain| global warming and waste management. Proposed disposal of high-level nuclear wastes containing primarily inorganic C-14 may provide a source of (CO2)-C-14 to the atmosphere. Field and laboratory experiments show that (CO2)-C-14 Soil degassing rate constants| the flux density (Bq.M2.s-1) divided by soil inventory (Bq-m-2)| range from -10(-7) to -10(-2) S-1| and that the loss of inorganic C-14 is driven primarily by gaseous diffusion. These constants are affected by soil pH and porosity| with smaller influences of soil temperature| moisture and organic matter content. Degassing rate constants derived through mass balance calculations to estimate loss differ only by 20% from direct trapping methods. Frozen soil degassing rate constants were up to 25 times smaller than lab values| indicating that annual C-14 loss rates in northern climates would be lower because of reduced gaseous diffusion during the winter months. Using our field data| we recommend an annual C-14 soil degassing rate constant of -1 x 10(-6) s-1 for acidic soils and a value of -5 x 10(-7) S-1 for calcareous soils. For probabilistic assessment modelling| we recommend a geometric mean degassing constant of -4.3 X 10(-7) S-1 with a geometric standard deviation of 3.26 for three different soils. This indicates the median half-life of C-14 in surface soils is 18 d| with a 99% confidence interval of 13 h and 640 d. 3856,1994,3,3,SOME CURRENT TRENDS IN RENEWABLE ENERGY FOR DEVELOPING-COUNTRIES,The paper reviews recent trends in renewable energy in developing countries including trends in funding| as well as in approaches and in technologies. Since the downturn in oil prices in the mid 1980's environmental concerns| especially fears of global warming| have replaced oil scarcity as a driving force in support of renewable energy. Decentralized solar photovoltaics (PV)| grid-connected windpower| biomass waste-to-energy conversion| and geothermal power appear to have the greatest near-term promise. Issues of human capacity building| access to credit| as well as the active involvement of the commercial sector are basic to progress in these areas. 3840,1994,4,3,SOME MODEL-BASED INFERENCE ABOUT GLOBAL WARMING,The magnitude of the response of global temperature to changes in atmospheric composition depends on a parameter called temperature sensitivity. The value of this parameter is unknown. When temperature sensitivity is estimated by fitting the response of a climate model forced by historical changes in atmospheric composition to the historical trend in global temperature| the estimate is rather low. It has been suggested that this may be due to the suppression of warming by sulphate aerosols| an effect that is difficult to incorporate into model experiments. This paper presents an approach to estimating temperature sensitivity based on historical temperature variability| rather than trend| which circumvents this problem. The results are in close agreement with those based on fitting the trend. 2612,1994,2,3,SPATIAL DISAGGREGATION FOR STUDIES OF CLIMATIC HYDROLOGIC SENSITIVITY,The use of deterministic atmospheric general circulation models (GCMs) to understand potential global climate change under doubled CO2 forcing has prompted a need for better understanding of local hydrologic impacts. Incongruities in model resolutions do not allow for GCM output to be directly used as forcing in the smaller-scale hydrologic models. In this work| daily spatial disaggregation techniques are applied to the upper Rio Grande basin in Colorado| simulating local temperature and precipitation regimes| and preserving spatial covariance structures at all spatial scales. Canadian Climate Centre GCM output is disaggregated to site-specific locations within the study basin. The Precipitation Runoff Modeling System is then used to examine hydrologic sensitivity under the disaggregated climate forcing. The results from this sensitivity indicate that under spatially disaggregated| site-specific| climatic forcing| significant snowpack-accumulation decreases occur. This results in total annual runoff decreases of| on average| 17.7%. A seasonal shift toward earlier in the year is observed in peak runoff| soil moisture storage| and evapotranspiration.
3891,1994,2,4,STELLAR LUMINOSITY VARIATIONS AND GLOBAL WARMING,Recent studies indicate that variation in the sun's luminosity is less than that observed in many other stars of similar magnetic activity. Current findings also indicate that in more active stars| the attenuation by faculae of sunspot luminosity modulation is less effective than in the sun at present. The sun could thus become photometrically more variable (and dimmer) if its magnetic activity exceeded present levels. But the levels of solar activity required for this to occur are not observed in carbon-14 and beryllium-10 records over the past several millennia| which indicates that such an increase in amplitude of surface magnetism-driven variations in solar luminosity is unlikely in the present epoch. 2653,1994,5,4,STRATIGRAPHIC DIVISION OF HOLOCENE LOESS IN CHINA,Loess deposition within the Loess Plateau of China records the history of environmental change over the last 2.5 Myr. Loess-paleosol sequences of the last 10 ka| which have preserved information of global climate change| relate closely to human occupation of the area. Hence| studies of the deposition and development of Holocene loess are significant for studying environmental change and problems associated with engineering geology. We present here stratigraphic relations among four profiles from the south| west and center of the Loess Plateau. On the basis of C-14 radiometric and AMS dates of organic material extracted from the paleosols| together with magnetic susceptibility measurements down each profile| we discuss Holocene stratigraphic divisions within the Loess Plateau| and suggest that the Holocene optimum| characterized by paleosol complexes| occurred between 10 and 5 ka BP. From 5 ka BP to the present| neoglacial activity is characterized by recently deposited loess.
2626,1994,4,4,SUSTAINABILITY IN CHINESE AGRICULTURE - CHALLENGE AND HOPE,Based upon a framework of three (i.e. biophysical| sociopolitical and techno-economic) dimensions of sustainability in agriculture| this paper discusses the current situation of Chinese agriculture in relation to sustainability. The main challenges are population pressure| land degradation| environmental pollution| global climate change| non-agricultural activities| market uncertainty| low level of capital investment| and some policy and behavioural conditions. However| there are opportunities related to natural resources| labour| education| science and technology| and some models of sustainable farming which already exist.
2656,1994,4,4,SYSTEMATICS AND NATURAL-HISTORY| FOUNDATIONS FOR UNDERSTANDING AND CONSERVING BIODIVERSITY,Enhanced by recent technical and conceptual advances| two classical endeavors in biology play vital roles in understanding| appreciating| and managing biodiversity. Systematics defines the fundamental units and relationships among living things; natural history chronicles the lifestyles of organisms in relation to environments. For example| analyses of evolutionary relationships emphasize the uniqueness of certain taxa| help prioritize groups of organisms for conservation| and enable us to estimate the biology of unstudied taxa. Radiotelemetry permits repeated location of snakes and other stealthy animals| facilitating previously impossible behavioral studies and thus laying the groundwork for effective management. Natural history in a systematic and geographic context provides a rule-of-thumb'' for predicting extinction due to global climate change. Educators should emphasize the urgency of the biodiversity crisis| inform debates about priorities for funding and other conservation matters| and teach about the goals| methods| and applications of systematics and natural history.
2654,1994,2,4,TEMPERATE COASTAL MARINE COMMUNITIES - BIODIVERSITY AND THREATS,Temperate marine ecosystems are some of the most productive and diverse of all ecosystems. Over the past century the resources contained within these communities have been subjected to gross mismanagement. They are continually subjected to threats from multiple stresses imposed mostly by human activities| predominantly as a result of increased population growth. The most significant categories of threats derive from: (1) habitat loss and degradation| (2) pollution from numerous sources including sewage| pesticides| pulp mills| thermal effluents| polychlorinated biphenyls| heavy metals| oil and radionuclides| (3) over-exploitation| (4) species introductions| (5) global climate change| (6) misguided human perceptions and (7) legal complexities. Furthermore| because subtidal and offshore coastal marine communities are not easily observed| their deterioration often goes mostly unnoticed. Impacts from stresses on coastal marine communities are manifested at the individual species level| but magnify in effect throughout the entire ecosystem because of complex inter-connected relationships between species at different trophic levels| including interactions such as predation| competition and mutualism. Therefore| one missing species or group of species that may be affected by some particular local pollutant| for example| may have unpredictable direct or indirect consequences through secondary effects on the ecosystem| possibly leading to the loss of a few to many species. Rather than striving to maintain some specific level of diversity| we should endeavor to understand the basic ecological processes that control populations| communities and ecosystems so we can best predict what kinds of stresses will cause the most serious alterations to the system and avoid them. In addition| we should be conservative about protecting systems even before we understand the processes fully.
3802,1994,4,3,THE ECONOMIC COSTS OF GLOBAL WARMING DAMAGE - A SURVEY,This paper provides an overview on literature dealing with an economic assessment of expected global warming damage. While a relatively large body of literature exists on other economic aspects of global warming| in particular the costs of carbon abatement| the question of greenhouse damage valuation has gained little attention so far. The first part of the paper surveys the results of existing analyses on the costs of global warming. The second part discusses the main shortcomings of these studies and the main problems faced by researchers in this area. 3837,1994,3,3,THE EFFECTIVENESS OF MARINE CO(2) DISPOSAL,We consider the relative effectiveness of engineered systems for collection and marine disposal of CO2 from fossil-fuel-fired power plants using comparisons of the trend with time of CO2 concentration in the atmosphere from systems with and without marine disposal. Since the retention time for CO2 increases rapidly with depth of disposal| from a few years in the mixed layer up to several centuries as the depth increases beyond 1000 m| deep oceans have been considered as potential storage sites for CO2. However| CO2 Collection and disposal consumes energy and produces extra CO2. We show that some of this extra CO2 reaches the atmosphere| so that atmospheric concentrations from systems with marine disposal ultimately exceed those from systems without controls. In some circumstances| they do so rapidly| making marine disposal less favorable than direct atmospheric release. The Global Warming Potential (GWP) can be used to compare different systems| but results for GWP highlight the difficult issue of determining what time scales are important in considering options to reduce concerns about global warming. 3924,1994,3,2,THE EFFECTIVENESS OF MEASURES TO REDUCE THE MAN-MADE GREENHOUSE-EFFECT - THE APPLICATION OF A CLIMATE-POLICY MODEL,In this paper we briefly describe the characteristics and the performance of our 1-D Muenster Climate Model. The model system consists of coupled models including gas cycle models| an energy balance model and a sea level rise model. The chemical feedback mechanisms among greenhouse gases are not included. This model| which is a scientifically-based parameterized simulation model| is used here primarily to help assess the effectiveness of various plausible policy options in mitigating the additional man-made greenhouse warming and the resulting sea level rise. For setting priorities it is important to assess the effectiveness of the various measures by which the greenhouse effect can be reduced. To this end we take a Scenario Business-as-Usual as a reference case (Leggett et al.| 1992) and study the mitigating effects of the following four packages of measures: The Copenhagen Agreements on CFC| HCFC| and halon reduction (GECR| 1992)| the Tropical Forest Preservation Plan of the Climate Enquete-Commission of the German Parliament on CO| reduction (ECGP| 1990)| a detailed reduction scheme for energy-related CO2 (ECGP| 1990)| and a preliminary scheme for CH4| CO| and N2O reduction (Bach and Jain| 1992-1993). The required reduction depends| among others| on the desired climate and ecosystem protection. This is defined by the Enquete-Commission and others as a mean global rate of surface temperature change of ca. 0.1-degrees-C per decade - assumed to be critical to many ecosystems - and a mean global warming ceiling of ca. 2-degrees-C in 2100 relative to 1860. Our results show that the Copenhagen Agreements| the Tropical Forest Preservation Plan| the energy-related CO2 reduction scheme| and the CH| and N2O reduction schemes could mitigate the anthropogenic greenhouse warming by ca. 12%| 6%| 35%| and 9% respectively. Taken together| all four packages of measures could reduce the man-made greenhouse effect by more than 60% until 2100; i.e. over the climate sensitivity range 2.5-degrees-C (1.5 to 4.5) for 2 x CO2| the warming could be reduced from 3.5-degrees-C (2.4 to 5.0) without specific measures to 1.3-degrees-C (0.9 to 2.0) with the above packages of measures; and likewise| the mean global sea level rise could be reduced from 65 cm (46 to 88) without specific measures to 32 cm (22 to 47) with the above measures. Finally| the model results also emphasize the importance of trace gases other than CO2 in mitigating additional man-made greenhouse warming. According to our preliminary estimates| CH4 could in the short term make a sizable contribution to the reduction of the greenhouse effect (because of its relatively short lifetime of 10 yr)| as could N2O in the medium and long term (with a relatively long lifetime of 150 yr). 3796,1994,4,4,THE ELDORA/ASTRAIA AIRBORNE DOPPLER WEATHER RADAR - GOALS| DESIGN| AND FIRST FIELD-TESTS,This paper describes the development and first operation of an innovative research tool for observing atmospheric storms: art airborne X-band Doppler radar. The radar has been built jointly by the National Center Sor Atmospheric Research (NCAR) in Boulder| CO and the Centre de Recherche en Physique de l'Environnement Terrestre et Planetaire (CRPE) in Paris| France. The radar is called ELDORA/ASTRAIA for Electra Doppler Radar/Analyse Stereoscopic par Radar Aeroporte sur Electra. The radar is designed to provide high-resolution measurements of the air motion and rainfall characteristics of very large storms. storms which are frequently too large and/or too I-emote to be adequately observed by ground-based radars. This paper includes discussions of the scientific impetus and design criteria| as well as the engineering solutions to these design needs. The design options and tradeoffs and the resulting capabilities are discussed. The paper concludes with an evaluation of the performance of the system at its first field lest| conducted as a part of the international global warming experiment in the equatorial Pacific Ocean known as the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). This evaluation illustrates that the major design goals for the radar-collection of relatively noise-free velocity and reflectivity data using a rapid scanning radar-have been adequately met. Future options for further improvements to the radar are discussed. 2640,1994,2,3,THE FLORA OF JAPAN AND THE IMPLICATION OF GLOBAL CLIMATIC-CHANGE,The influence of climate change induced by increasing atmospheric CO2 on the flora and vegetation of Japan is discussed. Nineteen small sized restricted plant-communities are evaluated as communities with a considerable number of species threatened under present scenarios of global climate change.
3885,1994,3,3,THE IMPACT OF HEAT-PUMPS ON GLOBAL WARMING AND OZONE DEPLETION,The heat pump| a proven and reliable technology| has the potential to reduce primary energy consumption and the corresponding CO2-emissions for heating and cooling in domestic| commercial and industrial applications. The basic principles of heat pump technology and the anthrogenic CO2-formation under the given energy supply and demand situation in Europe and the related impact on global warming are described. An analysis of the energy flow between primary energy exploitation and the useful energy of different heating systems clearly demonstrates the ability of electric heat pumps to reduce primary energy consumption in Europe between 15 and 50%| compared with oil- and gas-heating systems. The corresponding reduction of CO2-emissions will be between 20 and 60% and up to 85% of other pollutants. The present status of alternative working fluids which do not contribute to ozone depletion is presented and the direct (working fluids) and indirect (energy consumption) impact of different heat pumps on the greenhouse effect is discussed. 3926,1994,2,4,THE INFLUENCE OF WEATHER AND CLIMATE ON AGRICULTURALLY IMPORTANT INSECTS - AN AUSTRALIAN PERSPECTIVE,Weather and climate affect insects and other arthropods of importance to agriculture in a wide variety of ways. Pest and beneficial insects| and insect vectors of plant and animal diseases| are all influenced both directly and indirectly by temperature| rainfall| wind| etc. These influences can be immediate or cumulative| and they can act either at the production site or| in the case of migrant species| at locations distant from it. Weather and climate influence| often very significantly| the development rate| survival| fitness| and level of activity of individual insects; the phenology| distribution| size| and continuity of insect populations; migration and the re-establishment of populations following local extinction; the initiation of outbreaks; the susceptibility of crops and stock to insect attack; and the capacity of producers to manage insect populations. In Australia| the high variability of rainfall is of particular significance in determining the size and quality of insect populations. Windborne migration can be important for transporting these populations into agricultural regions| and low winter temperatures in the south of the continent limit the distribution of tropical species. Current Australian research on these topics is directed mainly at the development of pest-forecasting systems| and at estimating the impact of global greenhouse warming. 3914,1994,4,3,THE INTERACTIVE ATMOSPHERE - GLOBAL ATMOSPHERIC-BIOSPHERIC CHEMISTRY,The global atmosphere is a chemically complex and dynamic system| interacting both internally| mostly within the troposphere and stratosphere| and with the oceans| land| and living organisms. Its composition is changing today| and has also changed markedly over the last 160 000 yr. Environmentally-significant chemical processes occurring in the atmosphere include those affecting the ozone layer and the levels of radiatively active gases and particles. Methane| a very important greenhouse gas| has major natural and anthropogenic sources; it is destroyed largely by reaction with the hydroxyl radical in the troposphere. Both its sources and sink are strongly influenced by human activity. Nitrous oxide| with a similar range of sources| and chlorofluorocarbons| purely anthropogenic| are also greenhouse gases; however| their potency is offset partially by the ozone they destroy. Ozone| a key chemical and protective ultraviolet shield| has a complex chemistry influenced by many other trace species and is also an important greenhouse gas. Many other trace gases play a key role through their influence on the concentrations of ozone| the hydroxyl radical| and methane. Gaseous sulfur compounds| both natural and anthropogenic| are oxidized to particulate sulfates which have an important effect on albedo| counteracting the influence of the greenhouse gases. Atmospheric chemistry is therefore closely linked to industrial activity| climate| and land use through many complex environmental processes; these interactions cannot be realistically described by single numbers such as potentials for ozone depletion or global warming. The International Global Atmospheric Chemistry (IGAC) project is underway and dedicated to understanding this complex system through a combination of observations| theory| and laboratory and modelling studies. 3805,1994,3,3,THE MARGINAL COST OF CO2 EMISSIONS,Haraden's model for estimating the economic cost of global warming is analysed. We change his method of discounting and some of his input parameters in a manner consistent with physical and economic theory as well as empirical data. We then find much higher costs than Haraden found. These costs are compared to the cost of reducing CO2 emissions and we find that deep cuts of the emissions of CO2 are preferable. A check of the sensitivity of our results with respect to some crucial parameter values does not alter that conclusion. 3803,1994,2,4,THE POTENTIAL EFFECTS OF CLIMATE-CHANGE ON AUTUMN SOIL TILLAGE OPPORTUNITIES IN ENGLAND AND WALES,A model was used to estimate the number of autumn machinery work-days in England and Wales for a range of potential climate change sensitivity tests. The sensitivity tests were based on current best estimates of climate change and were referenced to a 30-year baseline climate. The analysis showed that decreases in precipitation have a much greater effect on the average number of work-days than increases in precipitation of a similar magnitude or increases in temperature of between 1 and 2 degrees C. A 2 degrees C increase in temperature was found to be off-set by a 10% increase in precipitation resulting in little change to the number of work-days compared with the baseline. The results suggested that autumn soil tillage opportunities will be improved by global warming unless precipitation increases substantially (by 15% or more). However| there are likely to be strong regional differences in the magnitude of this improvement. 2621,1994,2,4,THE RESPONSE OF TEMPERATE TREE SEEDLINGS GROWN IN ELEVATED CO2 TO EXTREME TEMPERATURE EVENTS,Mean global temperatures have been predicted to increase in the next century| if so the frequency of extreme temperature events may also increase. Extreme temperatures may damage plant tissue and consequently limit the survival of certain plant species in a region. Elevated concentrations of CO2 in the atmosphere alter plant allocation| physiology| and growth| and may accentuate or ameliorate the damage from extreme temperatures. In this paper we explore the interactive effects of atmospheric CO2 concentration| nutrient levels| and exposure to extreme temperatures on seedlings of three species of temperate deciduous trees. A1-d exposure to extreme heat (45-degrees-C) significantly decreased conductance the following day and decreased biomass as measured at both 35 and 105 d following the extreme temperature event| regardless of atmospheric CO2 concentration. The most shade-tolerant species| striped maple| was most severely impacted by the extreme heat event in both CO2 environments. Furthermore| striped maple seedlings grown in elevated CO2 concentrations had a significantly greater decrease in biomass due to the extreme heat event as compared with striped maple plants grown in ambient CO2 concentrations at 35 d after the heat event; however| al the end of the growing season at 105 d post treatment| this difference was not significant. A one-night exposure to low temperatures (4-degrees-C) did not affect biomass for any of these species. With an increase in global mean temperatures| the frequency of extreme temperature events| particularly hot weather events| may increase and may extend to shaded understory sites. If the frequency of extremely high temperatures increases| the role that temperature extremes may play in changing competitive interactions and thus affecting community composition may increase in importance| as these temperatures appear to severely alter plant survival and growth in some species.
3943,1994,3,2,THE ROLE OF REFRIGERANTS IN CLIMATE-CHANGE,The primary chemicals used as refrigerants| chlorofluorocarbons (CFCs)| and the compounds being considered as their replacements (HCFCs and HFCs) have been intensely studied because of concerns about chlorine chemistry effects on stratospheric ozone. Increasing attention is being given to the potential contributions of these compounds to global warming. CFCs| HCFCs and HFCs absorb infra-red radiation and thus are greenhouse gases that can exert an additional radiative forcing that tends to warm the climate. The purpose of this paper is to describe the current understanding of the role of refrigerants in affecting climate. Increasing atmospheric concentrations of CFCs have accounted for about 24% of the direct increase in radiative forcing from greenhouse gases over the last decade. However| an observed decrease in stratospheric ozone| thought to be connected to increasing stratospheric chlorine from CFCs (and| to a lesser extent| from other man-made compounds containing chlorine and bromine)| suggests a negative radiative forcing or cooling tendency over the last decade. This cooling tendency has strong latitudinal gradients| but is| when globally averaged| about comparable in magnitude and opposite in sign to the radiative forcing from CFCs over this period. On the other hand| the radiative influence on climate from the compounds being considered as replacements| because of their shorter atmospheric lifetimes| should generally be much smaller than the CFCs. However| the effects on ozone should also be much smaller from the replacement compounds and there should be less cancellation in the overall globally averaged influence on climate. 3929,1994,3,3,THE SIGNIFICANCE OF AGRICULTURAL SOURCES OF GREENHOUSE GASES,The impact of development of land for agriculture and agricultural production practices on emissions of greenhouse gases is reviewed and evaluated within the context of anthropogenic radiative forcing of climate. Combined| these activities are estimated to contribute about 25%| 65%| and 90% of total anthropogenic emissions of CO2| CH4| and N2O| respectively. Agriculture is also a significant contributor to global emissions of NH3| CO| and NO. Over the last 150 y| cumulative emissions of CO2 associated with land clearing for agriculture are comparable to those from combustion of fossil fuel| but the latter is the major source of CO2 at present and is projected to become more dominant in the future. Ruminant animals| rice paddies| and biomass burning are principal agricultural sources of CH4| and oxidation of CH4 by aerobic soils has been reduced by perturbations to natural N cycles. Agricultural sources of N2O have probably been substantially underestimated due to incomplete analysis of increased N flows in the environment| especially via NH3 volatilization from animal manures| leaching of NO3-| and increased use of biological N fixation. The contribution of agriculture to radiative forcing of climate is analyzed using data from the Intergovernmental Panel on Climate Change (IPCC)(base case) and cases where the global warming potential of CH4| and agricultural emissions of N2O are doubled. With these scenarios| agriculture| including land clearing| is estimated to contribute between 28-33% of the radiative forcing created over the next 100yr by 1990 anthropogenic emissions of CO2| CH4| and N2O. Analyses of the sources of agriculturally generated radiative climate forcing show that 80% is associated with tropical agriculture and that two-thirds comes from non-soil sources of greenhouse gases. The importance of agriculture to radiative forcing created by different countries varies widely and is illustrated by comparisons between the USA| India| and Brazil. Some caveats to these analyses include inadequate evaluations of the net greenhouse effects of agroecosystems| uncertainties in global fluxes of greenhouse gases| and incomplete understanding of tropospheric chemical processes. Extension of the analytical approach to projected future emissions of greenhouse gases (IPCC moderate growth scenario) indicates that agriculture will become a less important source of radiative forcing in the future. Technological approaches to mitigation of agricultural sources of greenhouse gases will probably focus on CH4 and N2O because emissions of CO2 are essentially associated with the socio-political issue of tropical deforestation. Available technologies include dietary supplements to reduce CH4 production by ruminant animals and various means of improving fertilizer N management to reduce N2O emissions. Increased storage of C in soil organic matter is not considered to be viable because of slow accretion rates and misconceptions about losses of soil organic matter from agricultural soils. 3934,1994,3,3,THE SOCIAL COSTS OF GREENHOUSE-GAS EMISSIONS - AN EXPECTED VALUE APPROACH,This paper provides an order-of-magnitude assessment of the marginal social costs of greenhouse gas emissions. The calculations are based on a stochastic greenhouse damage model in which key parameters are random. This allows a closer representation of current scientific understanding and also enables calculation of a damage probability distribution. Thus| we account explicitly for the uncertain nature of the global warming phenomenon. We estimate social costs of CO2 emissions in the order of 20 $/tC for emissions between 1991 and 2000| a value which rises over time to about 28 $/tC in 2021-2030. Similar figures for CH4 and N2O are also provided. As a consequence of the prevailing uncertainty| the standard deviation of the estimates is rather high. The distribution is positively skewed| which implies that the currently predominant method of using best guess values will lead to an underestimation of the expected costs of emissions. 3915,1994,2,4,THE USE OF DISCRIMINANT-ANALYSIS IN PREDICTING THE DISTRIBUTION OF BLUETONGUE VIRUS IN QUEENSLAND| AUSTRALIA,The climatic variables that were most useful in classifying the infection status of Queensland cattle herds with bluetongue virus were assessed using stepwise linear discriminant analysis. A discriminant function that included average annual rainfall and average daily maximum temperature was found to correctly classify 82.6% of uninfected herds and 72.4% of infected herds. Overall| the infection status of 74.1% of herds was correctly classified. The spatial distribution of infected herds was found to parallel that of the suspected vector| Culicoides brevitarsis. This evidence supports the role of this arthropod species as a vector of bluetongue viruses in Queensland. The effect of potential changes in temperature and rainfall (the so-called 'global warming' scenario) on the distribution of bluetongue virus infection of cattle herds in Queensland was then investigated. With an increase in both rainfall and temperature| the area of endemic bluetongue virus infection was predicted to extend a further 150 km inland in southern Queensland. The implications of this for sheep-raising in Queensland are discussed. 3852,1994,3,3,THE WAY AHEAD - WHY BUILD MORE NUCLEAR-PLANT AND WHY NOW,Nuclear power is already a major international industry and the single largest source of electricity in Europe. As the world demand for energy increases rapidly| the developing countries will rely heavily on their indigenous fossil fuels. The burning of fossil fuels will produce unacceptably high levels of global-warming gases| unless the developed nations reduce their reliance on fossil fuels. The UK's proven Sizewell design not only provides a means to develop home industries but offers increasing export opportunities. This - together with the potential loss of a nuclear skill base in the UK - should be borne in mind by Government as it contemplates the Nuclear Review. 2646,1994,4,3,TIME-SERIES ANALYSES OF GLOBAL CHANGE DATA,The hypothesis that statistical analyses of historical time series data can be used to separate the influences of natural variations from anthropogenic sources on global climate change is tested. Point| regional| national| and global temperature data are analyzed. Trend analyses for the period 1901-1987 suggest mean annual temperatures increased (in degrees-C per century) globally at the rate of about 0.5| in the USA at about 0.3| in the south-western USA desert region at about 1.2| and at the Walnut Gulch Experimental Watershed in south-eastern Arizona at about 0.8. However| the rates of temperature change are not constant but vary within the 87-year period Serial correlation and spectral density analysis of the temperature time series showed weak periodicities at various frequencies. The only common periodicity among the temperature series is an apparent cycle of about 43 years. The temperature time series were correlated with the Wolf sunspot index| atmospheric CO2 concentrations interpolated from the Siple ice core data| and atmospheric CO2 concentration data from Mauna Loa measurements. Correlation analysis of temperature data with concurrent data on atmospheric CO2 concentrations and the Wolf sunspot index support previously reported significant correlation over the 1901-1987 period. Correlation analysis between temperature| atmospheric CO2 concentration| and the Wolf sunspot index for the shorter period| 1958-1987| when continuous Mauna Loa CO2 data are available| suggest significant correlation between global warming and atmospheric CO2 concentrations but no significant correlation between global warming and the Wolf sunspot index. This may be because the Wolf sunspot index apparently increased from 1901 until about 1960 and then decreased thereafter| while global warming apparently continued to increase through 1987. Correlation of sunspot activity with global warming may be spurious but additional analyses are required to test this hypothesis. Given the inconclusive correlation between temperature and solar activity| the significant intercorrelation between time| temperature| and atmospheric CO2 concentrations| and the suggestion of weak periodicity in the temperature data| additional research is needed to separate the anthropogenic component from the natural variability in temperature when assessing local| regional| and global warming trends.
3935,1994,3,3,TRADABLE CUMULATIVE CO2 PERMITS AND GLOBAL WARMING CONTROL,As an alternative to current global warming policy proposals to freeze greenhouse gas ''emissions'' at their 1990 levels by the year 2000| this study examines the implications of a long-run objective of stabilizing greenhouse gas ''concentrations'' at low to moderate risk levels by the year 2100. The current proposals to control emissions slow but do not end the build-up of concentrations| and they could imply costly short-term adjustments of the energy industries. Our objective is to explore an alternative policy that could (1) stabilize induced climate change| (2) provide for the creation of international ''property rights'' in the stratosphere by means of tradable emission permits| and (3) be more intertemporally cost-effective. Our method for analyzing this effort is a tested| dynamic| price sensitive| global economic model to which is linked a climate change submodel. Together these models enable us to project price and quantity time paths of energy| climate| and tradable permit variables under alternative policy actions. 2642,1994,5,4,TROPICAL TEMPERATURE-VARIATIONS SINCE 20|000 YEARS AGO - MODULATING INTERHEMISPHERIC CLIMATE-CHANGE,Tropical sea surface temperatures (SSTs)| as thermodynamically recorded in Barbados corals| were 5-degrees-C colder than present values 19|000 years ago. Variable tropical SSTs may explain the interhemispheric synchroneity of global climate change as recorded in ice cores| snowline reconstructions| and vegetation records. Radiative changes due to cloud type and cloud cover are plausible mechanisms for maintaining cooler tropical SSTs in the past.
3938,1994,3,3,UPDATE OF REFRIGERANT ISSUES - ACCELERATED PHASE-OUT| SAFETY| AND REFRIGERANT MANAGEMENT,Chlorofluorocarbons (CFCs) have been identified as environmentally damaging compounds that destroy the ozone layer and threaten the existence of life on the planet. Additionally| CFCs are believed to contribute to global warming| with even greater environmental consequences. Public response to these concerns has led to international agreements to limit production and eventually phase out production altogether. The impact of complying with these new agreements and subsequent legislation and regulation is just now being understood by commercial building owners| who use CFC compounds as refrigerant fluids to air condition facilities. The phase out of CFC production mandates certain actions by facility managers. These will require investment in new equipment| increased maintenance costs| and extensive planning to avoid shortages and building operation disruption. Unfortunately| no single ''right'' answer exists to the CFC problem. The regulations are changing; new policies are evolving| and new equipment and refrigerant fluids are being developed| which may render today's solution inappropriate in the future. The building owner must evaluate the costs to comply| the costs of not complying| and the risks of numerous alternatives. 2649,1994,2,4,USING CROP MODELS AND GEOGRAPHIC INFORMATION-SYSTEMS TO STUDY THE IMPACT OF CLIMATE-CHANGE IN THE SOUTHEASTERN USA,Agricultural production is vulnerable to variability in weather conditions. Thus| projections of global climate change have prompted many studies on its possible impacts on agriculture. The aim of [is research was to develop a system to facilitate studies of the effects of climate change on crop production in the southeastern USA. The Agricultural and Environmental Geographic Information System (AEGIS V2.5) was developed by integrating field crop models for corn soybean| rice| wheat| peanut| and dry beans used in previous national and international studies on climate change with a Geographic Information System (GIS) on a personal computer. These crop models include the effects of CO2 on growth and yield and on crop water use. Soil and weather data are linked to map units so that model inputs as well as simulated results can be displayed over two dimensional space. The system allows users to alter management practices such as planting date| irrigation and cultivars| to study the possibilities of mitigating harmfill effects by adapting new practices. Example results for Florida show that non-irrigated crop yields will likely decrease and that irrigation demand would increase considerably under climate change scenarios. Examples results for Florida are displayed on a map to demonstrate the system.
2622,1994,4,4,VALIDATION OF MODEL IMPROVEMENTS FOR THE GISS GCM,The general circulation model of the NASA/Goddard Institute for Space Studies (GISS GCM) was designed primarily for global climate change and climate sensitivity applications. The modelling group at GISS has developed new and more physically appropriate parameterizations of meteorological/hydrological processes which are being validated in an effort to improve the performance of the Model II version of the GISS GCM. This study discusses some preliminary evaluations of this testing based on multiple-year simulations at 4-degrees latitude by 5-degrees longitude horizontal resolution. These runs individually incorporate new formulations of the planetary boundary layer (PBL)| the moist cumulus convection scheme and the ground hydrology and compare results using B-grid and C-grid numerics. The new PBL produces a realistically stronger tropical surface circulation| while the new cumulus scheme generates more realistic distributions of tropical convection and moisture. The main impact of the more sophisticated ground hydrology model is to increase surface air temperatures. Improvements in modelled sea level pressure and rainfall features by the C-grid are somewhat offset by increases in speed excesses at the cores of the summer hemisphere westerly jets. Each modelling innovation targeted a different aspect of the climate not adequately represented by Model II. However| since the various modelling changes were tested individually| the present evaluation could not demonstrate many dramatic improvements in the simulated climates. This documentation of impacts should| however| serve as a benchmark for the validation of future simulations of the GISS GCM that combine all of the modelling improvements.
3823,1994,2,4,WATER TEMPERATURE BEHAVIOR IN THE RIVER DANUBE DURING THE 20TH-CENTURY,Monthly mean water temperatures in the River Danube at Linz| Austria during the period 1901-1990 have been investigated in relation to equivalent information on air temperature and river discharge. Statistical analysis revealed a significant increase in monthly mean water temperatures of 0.8 degrees C and showed strongest rises in mean values for autumn and early winter months. No statistically significant trends were evident for air temperature or river discharge| and rising water temperatures are likely to reflect increasing human modification of the river system. A strong overall correlation between monthly mean water and air temperatures at Linz was made up of a series of more scattered and less steep water/air temperature relationships for individual months| while the influence of snowmelt runoff depressed average water temperatures in the spring and early summer period by 1.5 degrees C. Multiple regression relationships developed for individual months from data on air temperature| river discharge and time trend during the study period were able to predict monthly mean water temperatures in 1991 and 1992 with a root mean square error of 0.5 degrees C. These regression equations| when combined with scenarios of future changes in air temperature and river flow as a consequence of global warming| suggest that only modest rises in monthly mean water temperature will be experienced in the River Danube by the end of the present century| but that increases of >1 degrees C for all months| and >2 degrees C for the autumn period of low flows| can be anticipated by the year 2030. 2614,1994,2,4,WILD C-4 PLANTS IN GERMANY AND SWEDEN - A COMPILATION IN VIEW BY CLIMATE-CHANGE,48 species of wild C-4 plants are listed for Germany and Sweden. The difference in occurence of all species found (Germany: 47; Sweden: 23) and for the indigenous species (Germany: 9; Sweden: 3) is attributed to the temperature gradient. The most of the C-4 plants in either country occur as a result of anthropogenic influencies| in particular agriculture and industry. Only few species have been able to establish themselves in existing natural plant communities. One of the few examples is the Polygono-Chenopodietum plant society in the valleys of southern and central Germany. Analysis of the ecological characteristics revealed that C-4 plants are mostly annual herbs and adapted to high nutrient concentrations in soils. They are frequently found in saline areas| prefer well lit as well as maritime and climatically favoured locations. Most of the species are highly competitive. The changes in their spatial distributions presently observed| are closely connected to changes in land use efficiency. The shifting to the North of cultivated areas as a consequence of global climate change combined with the increased probability of extreme weather events may lead to a further spread of those C-4 species which are adapted. This effect is opposing the effect of increased CO2-concentrations which will favour C-3 plants.
4437,1995,2,4,70 YEARS OBSERVATIONS OF CHANGES IN DISTRIBUTION AND ABUNDANCE OF ZOOPLANKTON AND INTERTIDAL ORGANISMS IN THE WESTERN ENGLISH-CHANNEL IN RELATION TO RISING SEA TEMPERATURE,1. Extensive changes in marine communities in southwest Britain and the western English Channel have been recorded during the past 70 years. 2. Over the same period there was a climatic warming from the early 1920s| then a cooling to the early 1980s| with recent resumption of warming; the change in annual mean temperature was approximately +/-0.5 degrees C. 3. Marked changes occurred in plankton community structure; the distribution of both plankton and intertidal organisms was affected| with latitudinal shifts of up to 120 miles; there were increases or decreases of 2-3 orders of magnitude in abundance. 4. Warm water species increased in abundance and extended their range during periods of warming| while cold-water species declined or retreated; the reverse occurred during the period of cooling. 5. Climate change can influence marine communities by a combination of: direct effect on the organisms; effects mediated by biotic interactions; and indirectly through ocean currents. 6. From climate models that indicate rises of mean temperature of 2 degrees C in the next 50 years| and from the observed changes| we can expect future latitudinal shifts of 200-400 miles in distribution of plankton| fish and benthos| with extensive restructuring of planktonic| pelagic and benthic communities. 7. Species common now in the Bay of Biscay will become common in the English Channel; those presently restricted to the western English Channel could colonise the central Irish Sea; changes in community structure could lead to lower abundances of infaunal benthos and fish. 8. To fully prove the effects of global warming| future changes in the marine biota must exceed those recorded in the 1950s and 1960s. 4467,1995,2,4,A BOX MODEL STUDY OF THE GREENLAND SEA| NORWEGIAN SEA| AND ARCTIC-OCEAN,We develop a simple dynamical system model of the Arctic Ocean and marginal seas by applying the Martinson| Killworth and Gordon box model of a high-latitude two-layer ocean to four regions connected together: the Greenland Sea| the Norwegian Sea| the Arctic Ocean| and the Greenland Gyre. The latter is a small convective region embedded in the northwest corner of the Norwegian Sea. The model for each region consists of a thermodynamic ice layer that covers two layers of saline water which can| under specific conditions| become statically unstable and hence create a state of active overturning. The system is forced by monthly mean atmospheric temperatures in the four regions| by continental runoffs and by inflows from adjacent oceans. The model predicts the ice thickness| and the temperature and salinity of the water in the upper layer of the four regions. Also determined are the water temperature and salinity of the lower layer in the Arctic Ocean box. The convective state of any given region| i.e. whether it is in an active overturning mode or not| is also determined as a continuous function of time. The different output variables of the model| which are the response to climatological forcing conditions| compare favourably with observed data. In the control run| the Arctic Ocean region is characterized by continuous ice cover| the Greenland Sea and Greenland Gyre have ice cover only during winter| and the Norwegian Sea region never forms an ice cover. Another feature of the control run is the winter time occurrence of convective overturning in the upper 200 m in the Greenland Gyre region. The model is also used for different anomaly experiments: a positive air temperature anomaly which represents a global warming of the earth| a negative salt anomaly in the Norwegian Sea which simulates the great salinity anomaly of the 1960s and 1970s| and an increase in the ice flux through Fram Strait which parameterizes anomalous ice production in the Arctic. 4425,1995,4,2,A CLIMATE-CHANGE SIMULATION STARTING FROM 1935,Due to restrictions in the available computing resources and a lack of suitable observational data| transient climate change experiments with global coupled ocean-atmosphere models have been started from an initial state at equilibrium with the present day forcing. The historical development of greenhouse gas forcing from the onset of industrialization until the present has therefore been neglected. Studies with simplified models have shown that this ''cold start'' error leads to a serious underestimation of the anthropogenic global warming. In the present study| a 150-year integration has been carried out with a global coupled ocean-atmosphere model starting from the greenhouse gas concentration observed in 1935| i.e.| at an early time of industrialization. The model was forced with observed greenhouse gas concentrations up to 1985| and with the equivalent CO2 concentrations stipulated in Scenario A (''Business as Usual'') of the Intergovernmental Panel on Climate Change from 1985 to 2085. The early starting data alleviates some of the cold start problems. The global mean near surface temperature change in 2085 is about 0.3 K (ca. 10%) higher in the early industrialization experiment than in an integration with the same model and identical Scenario A greenhouse gas forcing| but with a start date in 1985. Comparisons between the experiments with early and late start dates show considerable differences in the amplitude of the regional climate change patterns| particularly for sea level. The early industrialization experiment can be used to obtain a first estimate of the detection time for a greenhouse-gas-induced near-surface temperature signal. Detection time estimates are obtained using globally and zonally averaged data from the experiment and a long control run| as well as principal component time series describing the evolution of the dominant signal and noise modes. The latter approach yields the earliest detection time (in the decade 1990-2000) for the time-evolving near-surface temperature signal. For global-mean temperatures or for temperatures averaged between 45-degrees-N and 45-degrees-S| the signal detection times are in the decades 2015-2025 and 2005-2015| respectively. The reduction of the ''cold start'' error in the early industrialization experiment makes it possible to separate the near-surface temperature signal from the noise about one decade earlier than in the experiment starting in 1985. We stress that these detection times are only valid in the context of the coupled model's internally-generated natural variability| which possibly underestimates low frequency fluctuations and does not incorporate the variance associated with changes in external forcing factors| such as anthropogenic sulfate aerosols| solar variability or volcanic dust. 4402,1995,3,3,A COST-BENEFIT-ANALYSIS OF SLOWING CLIMATE-CHANGE,This paper attempts to condense a mass of information relating to economic growth assumptions| carbon emissions forecasts| abatement cost estimates| and global warming damage functions and incorporate it into a cost-benefit analysis of slowing climate change| By these means it is possible to provide evidence on the extent to which society ought to incur control costs now in order to prevent future climate change using the rules commonly associated with project appraisal| In a business as usual scenario| the model predicts a temperature rise of 3.6 degrees C above preindustrial levels by the end of the next century inflicting damage with a present value of US$8.9 trillion| An optimal policy| however| seems to involve an immediate 12.7% cut in emissions and the establishment of 37.1 million hectares of forests| The optimal tax on carbon emissions for the year 2000 is estimated to be US$16.84 per tonne and the optimal policy reduces temperature rise by 0.3 degrees C relative to business as usual| By following the optimal policy| costs are reduced by US$700 billion| It is also suggested that policies to halt deforestation and remove the subsidies paid to fossil fuel producers might reduce overall costs by a further US$1.1 trillion. 4378,1995,4,3,A GLOBAL CLIMATE MODEL (GENESIS) WITH A LAND-SURFACE TRANSFER SCHEME (LSX) .2. CO2 SENSITIVITY,The sensitivity of the equilibrium climate to doubled atmospheric CO2 is investigated using the GENESIS global climate model version 1.02. The atmospheric general circulation model is a heavily modified version of the NCAR CCM1 and is coupled to a multicanopy land-surface model(LSX); multilayer models of soil| snow| and sea ice; and a slab ocean mixed layer. Features that are relatively new in CO2 sensitivity studies include explicit subgrid convective plumes| PBL mixing a diurnal cycle| a complex land-surface model| sea ice dynamics| and semi-Lagrangian transport of water vapor. The global annual surface-air warming in the model is 2.1 degrees C| with global precipitation increasing by 3.3%. Over mast land areas| most of the changes in precipitation are insignificant at the 5% level compared to interannual variability. Decreases in soil moisture in summer are not as large as in most previous models and only occur poleward of similar to 55 degrees N in Siberia| northern Canada|and Alaska. Sea ice area in September recedes by 62% in the Arctic and by 43% in the Antarctic. The area of Northern Hemispheric permafrost decreases by 48%| while the the total area of Northern Hemispheric snowcover in January decreases by only 13%. The effects of several modifications to the model physics are described. Replacing LSX and the multilayer soil with a single-layer bucket model causes little change to CO2 sensitivities on global scales| and the regions of summer drying in northern high latitudes are reproduced| although with somewhat greater amplitude. Compared to convective adjustment| penetrative plume convection increases the tropical Hadley Cell response but decreases the global warming slightly by 0.1 degrees to 0.3 degrees| contrary to several previous GCM studies in which penetrative convection was associated with greater CO2 warming. Similarly| the use of a cruder parameterization for cloud amount changes the local patterns of cloud response but has slight effect on the global warming. The authors discuss implications of the greater global warming (3.2 degrees C) found in an earlier version of the model and suggest that it was due to more detailed interactions that no longer occur in the current version. 4390,1995,4,4,A PROPOSAL FOR THE DEFINITION OF RESOURCE EQUIVALENCY FACTORS FOR USE IN PRODUCT LIFE-CYCLE ASSESSMENT,Environmental life-cycle assessment (LCA) of products has been the focus of growing attention in the last few years. The methodological framework has been developed rapidly| and a provisional ''Code of Practice'' has been drawn up by an international group of experts. One of the elements of LCA is impact assessment| which includes a characterization step in which the contributions of resource extraction and polluting emissions to impact categories such as resource depletion| global warming| and acidification are quantified and aggregated as far as possible. This can be achieved by multiplying extractions and emissions by a so-called equivalency factor and aggregating the results in one or more effect score(s) per impact category. In this report a proposal is developed for equivalency factors indicating the relative depletion of a resource per unit extracted. It is proposed to measure depletion by physical data on reserves and production and regeneration rates| and to distinguish between abiotic and biotic resources. Equations are developed to calculate equivalency factors for these two categories of resources| resulting in so-called abiotic depletion potentials (ADP) and biotic depletion potentials (BDP). The application of these ADPs and BDPs in LCA is illustrated. 2573,1995,2,3,A REASSESSMENT OF THE ECONOMIC-EFFECTS OF GLOBAL CLIMATE-CHANGE ON US AGRICULTURE,This study uses recent GCM forecasts| improved plant science and water supply data and refined economic modeling capabilities to reassess the economic consequences of long-term climate change on U.S. agriculture. Changes in crop yields| crop water demand and irrigation water arising from climate change result in changes in economic welfare. Economic consequences of the three GCM scenarios are mixed; GISS and GFDL-QFlux result in aggregate economic gains| UKMO implies losses. As in previous studies| the yield enhancing effects of atmospheric CO2 are an important determinant of potential economic consequences. Inclusion of changes in world food production and associated export changes generally have a positive affect on U.S. agriculture. As with previous studies| the magnitude of economic effects estimated here are a small percentage of U. S. agricultural value. 4391,1995,2,4,A SEA-LEVEL RISE CURVE FROM GUILFORD| CONNECTICUT| USA,High-resolution stratigraphic studies based on sediment chemistry| lithology| macroflora| and benthic foraminiferal assemblages in three peat cores from coastal salt marshes at Guilford| Connecticut| show that coastal marshes are ephemeral environments. Marsh-wide environmental variations were common| and century-long episodes of relative submergence alternated with emergence. Despite about 2 m of relative sea-level rise (RSLR) in Connecticut over the last 1500 years| the marshes have expanded both landwards and seawards| and marsh accretion has been outpaced only marginally by RSLR. We used radiocarbon dating and the level of anthropogenic markers (metal pollution| as dated with Pb-210) in the cores for age control. For most of the last 1000 years the rate of RSLR was between 1.3 and 1.8 mm/yr| but over the last 300-400 years it increased to 2.9-3.3 mm/yr| and has been faster than the accretion rate| especially in the middle marsh. The net-submergence rate or ''submergence index'' (ratio of the rate of RSLR and marsh-accretion rate) averaged about 1.15 over the last 1000 years| and increased to about 1.5 over the last 200 years. The rate of RSLR was very sluggish during the early part of the Little Ice Age| but we found a slightly higher rate during the Little Climate Optimum; this excursion is close to the noise level| however. The most significant observation is that RSLR increased strongly around A.D. 1650. The onset of this acceleration falls in the middle to end of the Little Ice Age| and thus preceded the period of modern global warming that started late last century and that has been tentatively correlated with anthropogenic emissions of greenhouse gases. 4321,1995,5,3,A SIMULATION OF MIDCRETACEOUS CLIMATE,A series of general circulation model experiments utilizing GENESIS have been completed for the mid-Cretaceous based on geography| variable atmospheric carbon dioxide concentrations (2 to 6 times present-day concentrations)| and variable poleward oceanic heat flux (.6 to 1.2 x 10(15) W increased from present day). By combining all three major variables (CO2| geography| and oceanic heat flux)| the distribution of mid-Cretaceous temperatures can be achieved. In the simulations| increased CO2 is required to promote global warmth| and increased oceanic heat flux is required to prevent the tropics from overheating with higher levels of CO2. Four times present-day CO2 with 1.2 x 10(15) W provided the best match to the distribution of mid-Cretaceous data. The best match to the Cretaceous observations was achieved with a globally averaged surface temperature increase of 6.2 degrees C| at the lower end of past estimates of mid-Cretaceous warmth. This value may be a better estimate of mid-Cretaceous global warming. Finally| the model experiments can be used to provide a ''paleocalibration'' of the global warming expected for a doubling of atmospheric carbon dioxide. The best estimates for the mid-Cretaceous appear to be a 2.5 to 4.0 degrees C sensitivity| in the mid to upper range of the sensitivity of current climate models used to assess future global change. 4301,1995,2,4,A size-distribution-based model of forest dynamics along a latitudinal environmental gradient,A geographically extended model of the dynamics of tree size structure of forests is proposed to simulate the change of forest zonation along latitude in response to global environmental change. To predict the response of forests to global change| it is necessary to construct functional models of forest tree populations. The size-structure-based model requires far less memory and steps of calculation compared with individual-based models| and it is easy to incorporate the dimension of geographic locations into the model to describe large-scale dynamics of forest-type distributions. The effect of increasing size growth rate| expected from increasing atmospheric carbon dioxide| was diminished at the stand-level basal area density| because of regulation by one-sided competition. Model simulations of a century-long global warming at around 3 degrees C predicted that (1) biomass changed in resident forests rather simultaneously in response to warming| and that (2) there was a considerable time lag in movement at the boundaries of different forest types| particularly under the existence of resident forest types that would be finally replaced. It required several thousand years after a century-long warming spell for forest types to attain new steady-state distributions after shifting. As a consequence| global warming created a zigzag pattern of biomass distribution along a latitudinal gradient| i.e.| an increase in the cooler-side boundary of forest types and a decrease in the warmer-side boundary. 2603,1995,2,4,A SUBGRID PARAMETERIZATION OF OROGRAPHIC PRECIPITATION,Estimates of the impact of global climate change on land surface hydrology require climate information on spatial scales far smaller than those explicitly resolved by global climate models of today and the foreseeable future. To bridge the gap between what is required and what is resolved| we propose a subgrid-scale parameterization of the influence of topography on clouds| precipitation| and land surface hydrology. The parameterization represents subgrid variations in surface elevation in terms of probability distributions of discrete elevation classes. Separate cloud| radiative| and surface processes are calculated for each elevation class. Rainshadow effects are not treated by the parameterization; they have to be explicitly resolved by the host model. The simulated surface temperature| precipitation| and snow cover for each elevation class are distributed to different geographical locations according to the spatial distribution of surface elevation within each grid cell. The subgrid parameterization has been implemented in the Pacific Northwest Laboratory's climate version of the Penn State/NCAR Mesoscale Model. The scheme is evaluated by driving the regional climate model with observed lateral boundary conditions for the Pacific Northwest and comparing simulated fields with surface observations. The method yields more realistic spatial distributions of precipitation and snow cover in mountainous areas and is considerably more computationally efficient than achieving high resolution by the use of nesting in the regional climate model. 4451,1995,4,4,A TOOL FOR MAPPING EVOLVING GEOSYSTEMS - A MODEL FOR A GLOBAL WARMING SCENARIO,Natural geosystems are mapped according to a new method. Spatially stable| time invariant data are linked with variable data. These later may be forced to meet the requirements of global warming models| thus enabling to map a new distribution of geosystems| for each chosen model. A Northern American exemple is presented. 4414,1995,4,4,AB-INITIO CALCULATIONS OF VIBRATIONAL FREQUENCIES AND INFRARED INTENSITIES FOR GLOBAL WARMING POTENTIAL OF CFC SUBSTITUTES - CF3CH2F (HFC-134A),We have investigated the feasibility of using ab initio molecular orbital methods for predicting the global warming potential of the proposed chlorofluorocarbon (CFC) substitute CF3CH2F| HFC-134a. Various levels of theory and basis sets were used to optimize geometry and calculate harmonic vibrational frequencies and infrared intensities for the molecule using the GAUSSIAN 92 software package. In attempting to assess the quality of the computations| we found it necessary to reconsider the vibrational assignments available in the literature. We have remeasured the infrared spectrum of the vapor from 400 to 4000 cm(-1) at a resolution (0.08 cm(-1)) sufficient to resolve some overlapping fundamentals and to assign symmetry species unambiguously for several bands on the basis of their rotational contours. The higher resolution spectra and the results of the computations together permit a firm assignment of all 18 fundamentals to be made. Some bands previously assigned as fundamentals are found to be combination or impurity bands. On the basis of the current assignment| we find that for the highest level calculation| MP2/6-31G**| the calculated harmonic frequencies agree extremely well with the experimentally observed ones at frequencies below 800 cm(-1)| with a systematic error toward higher calculated frequencies becoming apparent above 800 cm(-1). At lower levels of theory| the systematic error is apparent at all frequencies. The regularity of the deviation between calculated and observed frequencies makes ab initio calculations of vibrational frequencies much more useful than semiempirical calculations| which tend to show random deviations| as demonstrated with a PM3-UHF calculation in this work. The calculated absolute intensities are in good agreement with the limited experimental measurements previously reported| and the observed relative intensities for the fundamentals are also in approximate agreement with our calculated values. 4325,1995,2,4,ACCLIMATION OF LEAF DARK RESPIRATION TO TEMPERATURE IN ALPINE AND LOWLAND PLANT-SPECIES,Acclimation to temperature in terms of dark respiration by leaves is a missing link in current efforts to predict the effects of global warming on plant communities. We studied the acclimation of plants from alpine or lowland areas and asked two questions: (1) do plants acclimate to a change in temperature and does acclimation depend on the plants' origin; and (2) have alpine plants adapted to low temperatures by respiring faster than lowland plants at any given temperature? Nineteen alpine and corresponding lowland species| collected in Switzerland| were grown at 10 and 20 degrees C for 5 weeks. Night-time leaf dark respiration rates were measured at the growth temperature of each plant. Acclimation patterns ranged from full to no acclimation. Full acclimation to temperature| defined as the equality between respiration measured at 20 degrees C of plants grown at 20 degrees C and respiration measured at 10 degrees C of plants grown at 10 degrees C| occurred in only three our of 19 species. Dark respiration of leaves was stimulated by a 10 K warming| but on average| by about 50% less than predicted by the instantaneous temperature response| i.e. Q(10). Acclimation did nor depend on the alpine or lowland origin of the plant| but rather on its genus. Prostrate alpine plants displayed the lowest acclimation potential. We conclude that predictions at the community level cannot be made based on single species because of the variety observed in the respiration responses. (C) 1995 Annals of Botany Company 4438,1995,2,4,ADAPTATION OF FISH TO DIFFERENT ENVIRONMENTAL-TEMPERATURE BY QUALITATIVE AND QUANTITATIVE CHANGES IN GENE-EXPRESSION,In fish that occupy a specific thermal habitat the contractile apparatus has been adapted during evolution for that specific temperature range. In Antarctic fish the myofibrillar GTPase activity is relatively high at temperatures around 0 degrees C| but this is at the expense of enzyme thermostability as this enzyme from antarctic fishes is heat inactivated at comparatively low temperatures (Johnston and Goldspink| 1975c; Johnston and Walesby| 1977). Such thermal characteristics may be a general feature of proteins from Antarctic fish (Somero| 1991) and so may contribute to their extreme cold stenothermy. Some eurythermal species of fish have the ability to rebuild their contractile systems by expressing a different set of genes at low temperature to that expressed at warm environmental temperatures. We have cloned and are in the process of characterising warm and cold as well as embryonic myosin heavy chain isoform genes of carp. These genes encode different types of myosin crossbridges (the force generators for muscular contraction) and therefore determine the contractile characteristics of the muscle. The physiological result of the switches in gene expression are that the muscles of fish acclimated to low environmental temperatures develop more force and more power at these temperatures than muscles from fish acclimated to warm environmental temperatures. Carp acclimated to warm temperatures have myosin with a greater thermostability but at a lower myofibrillar ATPase. 4293,1995,3,4,Agroforestry developments and potential in the Brazilian Amazon,Much attention in the media and scientific literature has focused on the destruction of tropical forests in Amazonia since the early 1970s| especially in the Brazilian states of Rondonia| Acre| Para and Mate Grosso. Concern is mounting that the peeling back of the forests is wiping out biodiversity| destroying soil resources| possibly exacerbating global warming| and provoking land conflicts| among other socioeconomic and ecological problems. Yet little regard has been paid to some of the promising agricultural developments in the region that are helping to counteract pressures on the remaining forest while recuperating debilitated areas. In particular| a pronounced trend towards planting a mix of tree crops on small farms throughout the basin augers well for the future of the rainforest and more sustainable agriculture. Agroforestry developments in Amazonia underscore the linkages between conserving biodiversity and more productive and resilient agricultural systems. 2599,1995,2,4,AIR-QUALITY AND ITS POSSIBLE IMPACTS ON THE TERRESTRIAL ECOSYSTEMS OF THE NORTH-AMERICAN GREAT-PLAINS - AN OVERVIEW,Over the past several decades| numerous studies have been conducted on the impacts of air pollutants (air quality) on terrestrial ecosystems (crops and forests). Although ambient air is always composed of pollutant mixtures| in determining the relative air quality and its ecosystem impacts at a given geographic location and time| a predominant number of studies have shown that at the present time surface level O-3 is the most important phytotoxic air pollutant. Within the North American Great Plains| the precursors; for surface-level O-3 are mainly anthropogenic NOx and VOCs (volatile organic compounds). Texas and Alberta ta are the top regions of such emissions in the United States and Canada| respectively. This appears to be due mainly to the prevalence of natural gas and/or oil industry in the two regions and the consequent urbanization. Nevertheless| the total emissions of NOx and VOCs within the North American Great Plains represent only about 25-36% of the corresponding total emissions within the contiguous United States and the whole of Canada. Within the Great Plains many major crop and tree species are known to be sensitive to O-3. This sensitivity assessment| however| is based mainly on our knowledge from univariate (O-3 only) exposure-plant response studies. In the context of global climate change| in almost all similar univariate studies| elevated CO2| concentrations have produced increases in plant biomass (both crop and tree species). The question remains as to whether this stimulation will offset any adverse effects of elevated surface O-3 concentrations. Future research must address this important issue both for the Great Plains and for all other geographic locations| taking into consideration spatial and temporal variabilities in the ambient concentrations of the two trace gases. 4339,1995,4,4,AIR-TEMPERATURE VARIATIONS AND ENSO EFFECTS IN INDONESIA| THE PHILIPPINES AND EL-SALVADOR - ENSO PATTERNS AND CHANGES FROM 1866-1993,The major features in development of the ''El Nine-Southern Oscillation'' (ENSO) involve oscillation of the Pacific ocean-atmosphere in an essentially unpredictable (chaotic) fashion. The system moves between extremes of the so-called ''warm events'' lasting one or two years and involving movement of warm sea water from the western Pacific along the equator to impact on the west coast of the American continent and ''cold-events'' associated with easterly trade-wind-induced flows of colder water from the eastern Pacific towards the west. Historical data indicate that ENSO years as experienced by the Island of Java are either much warmer than non-ENSO years or only slightly| if at all| warmer than normal (non-ENSO) years. Hot-dry years within the ENSO warm event cycle are almost always followed by cooler wet years and vice versa. This pattern also extends to include the year immediately following the terminal year of an ENSO warm event set. The initial year of an ENSO warm event set may be either hot with a long dry season or relatively cool (nearer to the temperature of a non-ENSO year) and having a short dry season. In recent years| since 1950| of the 9 ENSO warm. events| the initial year tends to have been hot and dry for 6 (1951| 1957| 1963| 1972| 1982| 1991) and neutral or cool and wet for 3 (1968| 1976| 1986). An area of 88|000 ha burned in 1991 (Jakarta Post 30 November 1991) largely in Kalimantan in association with the 1991-1992 ENSO event| an extensive pall of smoke developed over Kalimantan| Singapore and Malaysia during September-October of 1991. Surface vegetation-based fires continued to burn in East Kalimantan as of 29 April 1992 and extended into the 1992 dry season| in response to the ENSO conditions carrying forward from 1991. The increasing annual trend in air-temperature exhibited by the mean monthly values over the period 1856-1993| for the Jakarta and the Semarang data taken together is 1.64 degrees C (0.0132 degrees C per year from 25.771 to 27.409 degrees C). The major industrial development in infrastructure for Jakarta has been significant only since 1980 or so and was not apparent before 1970 when the city had the aspect of an extended village with few large buildings (greater than 3-4 stories) and no extensive highways. The 1.65 degrees difference between 1866 and 1991 can presumably be partitioned into: (1) urban heat-island effect| (2) effect of deforestation| (3) effect of secular micro-climate shift| (4) influence of general global warming with particular reference to the tropics. When the blocks of non-ENSO years in themselves are considered| the deviations from the secular trend for warmest month mean temperatures in successive years are correlated with that of the next immediate year deviation so that either continual warming or cooling appears to take place from the termination of one ENSO to the initiation of the next. When the deviations around the secular trend shown by the warmest month average temperatures are summed for the inter-ENSO intervals (the separate non-ENSO years) the resultant ''heat-loading'' index is positively correlated with the following (initial) ENSO warmest month deviation from the overall ENSO warmest month secular trend. This provides an immediate predictive mechanism for the likely strength of an ENSO| in terms of the dry season impact to the Island of Java| should one occur in the next year to break a non-ENSO sequence. The length of the build-up and the build-up achieved seems not to be related. The relationship does not in itself however| predict the occurrence of the ''next'' ENSO. The data show that a consistent structure underlies ENSO events for the last century and a quarter. However| as a process monitored by mean monthly air-temperature measurements at Jakarta-Semarang| the system is changing in character with time in association with an overall atmospheric temperature increase in a way that involves increased intra-annual temperature fluctuations. In general ENSO years are associated with higher temperatures than non-ENSO years| with a significant negative correlation between subsequent years which are thereafter systematically cooler. This may be because the ENSO event actively mixes excess heat energy into the ocean-sink to an extent that is in direct proportion to the outstanding positive temperature deviation. A weak ENSO| preceded by a relatively modest temperature build-up in the lead-up non-ENSO years| then results in limited mixing which leads to a relatively warm subsequent year while a strong event leads to extensive mixing and so generally results in a following very much cooler year. Atmospheric temperature build-up possibly associated with the greenhouse effect may be coupled to an increasingly wider temperature swing in west and central Java associated with the warm pool influence but anchored by the ocean-sink. 2592,1995,2,3,An approach to modelling spatial changes of plant carbon:nitrogen ratios in southern Africa in relation to anticipated global climate change,The carbon to nitrogen (C:N) ratio is the main factor determining the forage quality of a plant| with a low C:N ratio indicating relatively good plant digestibility and a high C:N ratio inferring relatively poor forage quality. Global atmospheric composition and climate change effects on plant carbon to nitrogen ratios are thus likely to be important when predicting possible second-order impacts of the enhanced greenhouse effect on rangeland forage quality and the resultant feeding habits of foraging animals and herbivorous insects. Equations relating the assimilation of total carbon and nitrogen rates to monthly air temperature| the ambient CO2 level and soil fertility were used together with detailed spatial climatic and soil databases to simulate regional patterns of C:N ratios over southern Africa. Carbon to nitrogen ratios were estimated for both the present climate and for a possible future climate scenario defined by a general 2 degrees C mean daily temperature increase over southern Africa (but with latitudinal| seasonal and diurnal adjustments made)| an increase in atmospheric CO2 concentration from 360 to 560 ppmv| but with no changes in precipitation patterns. When C:N differences between future and present climates are examined| results indicate both relative increases and decreases over southern Africa in a regional context| ranging from - 8 to + 8%. Areas where the C:N ratios decreased indicate that for the future climate scenario which was assumed the relative increase in assimilated nitrogen would be greater than that for carbon. Similarly| areas where the C:N ratios increased indicate that the relative increase in assimilated carbon would be greater than that for nitrogen. In this study| regions sensitive to climate change effects on C:N ratios in southern Africa have therefore been identified and with that| those areas where the consumption of plant matter may be expected to increase or decrease as a result of anticipated global climate change. 2585,1995,3,3,AN INTEGRATED FRAMEWORK TO ADDRESS CLIMATE-CHANGE (ESCAPE) AND FURTHER DEVELOPMENTS OF THE GLOBAL AND REGIONAL CLIMATE MODULES (MAGICC),ESCAPE (the Evaluation of Strategies to address Climate change by Adapting to and Preventing Emissions) is an integrated climate change assessment model constructed between 1990 and 1999 for DG XI of the Commission of the European Community by a consortium of research institutes headed by the Climatic Research Unit (CRU)| It has been designed to enable the user to generate future scenarios of greenhouse gas emissions (through an energy-economic model)| examine their impact on global climate and sea level (through two independent global climate models)| and illustrate some of the consequences of this global climate change at a regional scale for the European Community (through a regional climate scenario generator and impact models)| We provide a very brief overview of the ESCAPE model which| although innovative| suffers from a number of major limitations| Subsequent work in the CRU has concentrated on improvements to the global climate module and work has also commenced on an improved regional climate scenario generating module. These improvements will lead to a new integrated climate change assessment model| MAGICC (Model for the Assessment of Greenhouse gas Induced Climate Change) which can easily be incorporated into new larger integrated frameworks developed by other institutes. 2545,1995,4,4,AN INTERCOMPARISON OF WET PRECIPITATION SCAVENGING SCHEMES AND THE EMISSION RATES OF RN-222 FOR THE SIMULATION OF GLOBAL TRANSPORT AND DEPOSITION OF PB-210,We simulated the transport of Rn-222 and its progeny Pb-210 using a global three-dimensional atmospheric tracer transport model. The purpose of this study was to understand the effects of wet deposition scavenging processes and the emission rate of Rn-222 On the global transport and deposition of Pb-210. We examined the deposition of Pb-210 aerosols due to wet scavenging in stratiform and convective precipitation. Four schemes for wet precipitation scavenging removal| and two assumed distributions of the emission rate of Rn-222| were studied and tested. One was assumed to have a global constant rate and in the other the constant rate was assumed to have changed with latitude. The results of the model simulations were compared with archived radionuclide data measurements from the Environmental Measurements Laboratory's global network of sampling stations. The model-calculated global distributions of the yearly mean of the surface air concentrations of Rn-222 and Pb-210| and the yearly mean total deposition of Pb-210 for 1986 data for each wet precipitation scavenging scheme studied are presented. For each scheme| we have also compared yearly mean total deposition and monthly averages of the surface air concentrations and the vertical distributions of Pb-210 with the measurements. We found that the Walton et al. (1988) scheme produces the best results of the four schemes studied. Although this scheme| when utilizing a constant emission rate| gives satisfactory results| use of an emission rate that changes with latitudes improves the bias of this scheme| particularly at high northern latitude sites. The model comparisons with the measurements helped us to validate and improve the model. This atmospheric tracer transport model can be used for the simulation of other radionuclide and nonradionuclide tracers for future studies related to global climate change. 4441,1995,2,4,ANNUAL BREEDING CYCLES IN MARINE-INVERTEBRATES AND ENVIRONMENTAL-TEMPERATURE - PROBING THE PROXIMATE AND ULTIMATE CAUSES OF REPRODUCTIVE SYNCHRONY,1. A general model of an annual reproductive cycle is developed and presented in two forms for semelparous and iteroparous organisms. 2. In the model a fixed period for spawning implies a fixed phase relationship between all components of the cycle and those external variables with an annual component. Causal relationships cannot be established by observations of concurence. 3. The physiological basis of causal relationship is being established for a number of marine invertebrate groups and some polychaete case histories are reviewed. 4. An important role for endogenous timing mechanisms that interact with external variables including temperature but also seasonal photoperiod and other factors is established. 5. An increase in mean sea temperature would cause a change in the temperature phase relationships of annual reproductive cycles when photoperiod has a significant role in the timing mechanism. 6. Local variation in the responses to environmental signals are expected in populations in different parts of the geographical range. Gene flow would provide a mechanism by which populations would respond to reductions of fitness arising from the changed phase relationships that are implied by global warming. 4336,1995,4,3,ANTHROPOGENIC ENVIRONMENTAL-POLLUTION - THE SHARE OF AGRICULTURE,The increase of environmental pollution is in direct relation to the consumption of fossil coal| gas and oil and the progressive growth of the world population. Since 1950 these issues increased considerably and they will continue to increase in the future. At the moment the population increases by 1.9 %| the consumption of energy between 2 and 3 % and the environmental pollution up to 3.5 % annually. With the progressive growth of the world population and the increase in prosperity in the developed countries the demand for food increased also progressively and therewith the productivity index of the units of arable land| by growing consumption of fertilizers and the installation of irrigation systems. At the same time the pollution of air| water and soil caused by agriculture also grew progressively. But up to date there is still a shortcoming of reliable statistical facts and figures. A higher productivity index of the units of arable land in the different ecoclimatic zones of the earth leads to higher production and consumption by an inevitably higher turnover of plant nutrients and diverse gaseous substances| for example carbon mono- and dioxide| diverse compounds of nitrogen etc. At the same time an excess of the ''critical loads'' for soil| air and water must be expected. The main items of the emissions produced by an intensified agriculture are| besides carbon mono- and dioxide| methane| nitric and nitrous oxide| ammonia and diverse hydrocarbons. A higher productivity index is consequently related to a higher consumption. This also leads to an intensified turnover of carbon dioxide. There is consequently a progressive input of carbon dioxide resulting from the emissions of burning fossil fuel in the recently produced and consumed biomass. This inevitably leads to a higher level of carbon dioxide in the air. A main source of emissions of methane and ammonia is animal breeding. In Austria at this time from each of the 3|508.000 hectars of land used by agriculture annual emissions of 63 kg methane and 11 kg ammonia are resulting theoretically. The use of organic and inorganic fertilizers| the growing cultivation of legumes and the emissions of nitrogen compounds resulting from burning processes elevate likewise the pool and the annual turnover of nitrogen compounds by production and consumption of biomass. Inevitably related to it is a growing amount of the annual input of nitrogen compounds to the air| the soil and the water. A rough approximation says that at present agriculture contributes to the global anthropogenic pollution of the environment (air| soil and water) 85 % of the ammonia| 81 % of the nitrous oxide| 35 % of nitric mono- and dioxide| 70 % of the methane| 52 % of the carbon monoxide and 21 % of the carbon dioxide. Not considered in the figure for carbon dioxide is the inevitable increase of the level of CO2 in the air by the elevated turnover of biomass. The world population growth in the future leads to an increasing contribution of agriculture to the anthropogenic environmental pollution. For the developed countries this is an obligatory challenge to avoid surplus production. On a global scale there must be a sensible reduction of animal breeding to reduce the high emissions of methane and ammonia from this sector of agriculture. It must also be considered| that by feeding animals with vegetable food stuff| which also could be used for direct nutrition of man| the efficiency of it is lowered by a factor of 1:10. In spite of a growing crisis to maintain the alimentation of the growing world population in many countries the nutrition of man must rapidly be centered on vegetable food stuff rich in protein. At the same time an essential reduction of the environmental pollution resulting from animal breeding could be realized. Beside of it and other reducing issues a continuous growth of the world population| the energy consumption and environmental pollution will make it necessary to observe the development and reactions in the environment by monitoring and phenological observations. The results must be used to counteract finally by looking for adaptation strategies. Considering the realities it must be realized that by all means to mobilize for counteracting the environmental pollution directly| a certain climate change will be inevitable. The consequences will also be an outstanding challenge for the agriculture. 4387,1995,3,4,APPROACHES AND CHALLENGES TO USE FREON PROPELLANT REPLACEMENTS,Freon propellants commonly referred to as chlorofluorocarbons (CFCs) are involved in the destruction of the ozone layer. The countries participating in the Montreal Protocol voted in 1990 to require a phase-out of CFC production by the year 2000. In 1992| the phase-out was moved forward to 1996. There are two pharmaceutical consortia evaluating replacements for CFCs in metered dose inhalers (MDIs)| which include the development of HFA-134a by IPACT-I and the development of HFA-227 by IPACT-II. Neither of these replacement propellants contains chlorine so they have no potential to destroy ozone. In addition| each of these new propellants has less global warming potential than currently used CFCs. The IPACT organizations have comprehensive testing programs developed from consultation with global regulatory authorities. These programs are largely complete with respect to subchronic evaluations and current work is focused on long-term evaluations. Results have indicated that the new propellants are extremely benign and have an equal or better safety profile than the CFCs they are meant to replace. With the safety of the new propellants becoming more evident with time| new formulations of existing aerosol drugs are being developed. This testing includes stand-alone safety evaluations as well as studies of the drug in new propellant formulations directly compared to current CFC formulations. Comparison studies have shown that the safety profile of the new formulations is not different from that of the CFC formulations. In summary| the availability and desirability of the use of CFCs in MDIs is limited. Fortunately several alternative propellants to the CFCs are approaching development finalization. The testing program has shown that these replacements are acceptable from a safety assessment perspective and their introduction will assure that vital MDI therapy will continue uninterrupted. 4376,1995,2,4,ARTIFICIAL REGENERATION OF SPRUCE ON COLD| WET SOIL - 10 YEARS ALONG,Ten year results are presented from two reforestation sites in the Bowron drainage of British Columbia. Spruce (Picea glauca| P. engelmannii) of the same seedlot and stocktype| was planted at the same time on the same site-types. Site 1 (S1) utilized different sizes of inverted mineral mound s and Site 2 (S2) used mounding coupled with herbicide (glyphosate) site preparation or brushing treatments. Ten year survival on mounds was 100% at 52 and greater than 90% at S1. Control treatment survival was 34 and 66% at S1 and S2| respectively. Mounding increased 10 year stem volume (SV) by more than 300% over control at S1. Mounding or herbicide site preparation approximately doubled the SV over control while mounding plus herbicide site preparation resulted in a three fold increase of SV at S2. Pissoides leader weevil incidence was at endemic levels at both sites but it is expected to increase if global warming scenarios hold. This would reduce future site productivity. The most costly treatment to establish at S2| mounding plus herbicide site preparation| was the most cost effective at year 10. These data suggest that spending more at establishment can result in greater survival| growth and return on investment. 2562,1995,3,3,ASSESSING BRAZIL CARBON BUDGET .1. BIOTIC CARBON POOLS,Brazil contains the world's largest expanse of tropical forest| but its forests are experiencing high levels of conversion to other uses. There is concern that releases of CO2 and other greenhouse gases resulting from deforestation will contribute to global climate change| The total amount of C that could be released by deforestation depends upon the amount currently contained in the terrestrial biota and soils. Knowledge of the areas of Brazil's major ecosystems and land use types and their C densities was used to estimate the total amount of C stored in vegetation| litter and coarse woody debris| and soils| The total estimated C pools were (58-81) X 10(9) Mg C in vegetation| (6-9) X 10(9) Mg C in litter and coarse woody debris| and about 72 X 10(9) Mg C in soil. Over 80% of the vegetation pool was contained in the closed tropical moist forests of Brazil. 4456,1995,2,4,Atmospheric chemistry and environmental impact of hydrofluorocarbons and hydrochlorofluorocarbons,We review the available data concerning the atmospheric chemistry and environmental impact of a series of important hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). HFCs have no impact on stratospheric ozone. HCFCs have ozone depiction potentials which are 10-100 times less than CFCs. The direct global warming potentials of HFCs and HCFCs are approximately an order of magnitude less than those of the CFCs they replace. At the concentrations expected from their atmospheric degradation| none of the oxidation products of HFCs or HCFCs are noxious or toxic (e.g.| the concentration of CF3COOH in rainwater will be 3-4 orders of magnitude lower than that reported to have an impact on plants). 4410,1995,2,4,ATMOSPHERIC CO2| SOIL-NITROGEN AND TURNOVER OF FINE ROOTS,In most natural ecosystems a significant portion of carbon fixed through photosynthesis is allocated to the production and maintenance of fine roots| the ephemeral portion of the root system that absorbs growth-limiting moisture and nutrients. In turn| senescence of fine roots can be the greatest source of C input to forest soils. Consequently| important questions in ecology entail the extent to which increasing atmospheric CO2 may alter the allocation of carbon to| and demography of| fine roots. Using microvideo and image analysis technology| we demonstrate that elevated atmospheric CO2 increases the rates of both fine root production and mortality. Rates of root mortality also increased substantially as soil nitrogen availability increased| regardless of CO2 concentration. Nitrogen greatly influenced the proportional allocation of carbon to leaves vs. fine roots. The amount of available nitrogen in the soil appears to be the most important factor regulating fine root demography in Populus trees. 2569,1995,5,4,BE-10 DATING OF THE DURATION AND RETREAT OF THE LAST PINEDALE GLACIAL SEQUENCE,Accurate terrestrial glacial chronologies are needed for comparison with the marine record to establish the dynamics of global climate change during transitions from glacial to interglacial regimes. Cosmogenic beryllium-10 measurements in the Wind River Range indicate that the last glacial maximum (marine oxygen isotope stage 2) was achieved there by 21|700 +/- 700 beryllium-10 years and lasted 5900 years. Ages of a sequence of recessional moraines and striated bedrock surfaces show that the initial deglaciation was rapid and that the entire glacial system retreated 33 kilometers to the cirque basin by 12|100 +/- 500 beryllium-10 years. 2606,1995,4,4,BLUE HOLES - DEFINITION AND GENESIS,Blue holes are karst features that were initially described from Bahamian islands and banks| which have been documented for over 100 years. They are water-fined vertical openings in the carbonate rock that exhibit complex morphologies| ecologies| and water chemistries. Their deep blue color| for which they are named| is the result of their great depth| and they may lead to cave systems below sea level Blue holes are polygenetic in origin| having formed: by drowning of dissolutional sinkholes and shafts developed in the vadose zone; by phreatic dissolution along an ascending halocline; by progradational collapse upward from deep dissolution voids produced in the phreatic zone; or by fracture of the bank: margin. Blue holes are the cumulative result of carbonate deposition and dissolution cycles which have been controlled by Quaternary glacioeustatic fluctuations of sea-level. Blue holes have been widely studied during the past 30 years| and they have provided information regarding karst processes| global climate change| marine ecology| and carbonate geochemistry. The literature contains a wealth of references regarding blue holes that are at times misleading| and often confusing. To standardize use of the term blue hob| and to familiarize the scientific community with their nature| we herein define them as follows: ''Blue holes are subsurface voids that are developed in carbonate banks and islands; are open to the earth's surface; contain tidally-influenced waters of fresh| marine| or mixed chemistry; extend below sea level for a majority of their depth; and may provide access to submerged cave passages.'' Blue holes are found in two settings: ocean holes open directly into the present marine environment and usually contain marine water with tidal now; inland blue holes are isolated by present topography from surface marine conditions| and open directly onto the land surface or into an isolated pond or lake| and contain tidally-influenced water of a variety of chemistries from fresh to marine. 2590,1995,2,4,BRAZIL CARBON BUDGET FOR 1990S,A major reason for alarm over the rate and magnitude of deforestation in Brazil has been concern that the reduction in vegetation releases carbon dioxide (CO2) and other greenhouse gases (GHG) that may contribute to global climate change. While deforestation releases CO2 and other GHG| however| tree growth elsewhere absorbs atmospheric carbon (C) through photosynthesis. discussions of CO2 releases from tropical deforestation have tended to focus on gross releases and have generally not considered the effects of carbon uptake. The objective of this paper is to examine the net C balance for Brazil| by estimating both CO2 - C release and uptake. Our approach was to construct a generalized conceptual model of ecosystem C cycling that could be applied to any vegetation type and can be quantified with available data. the primary C pools in the model are the atmosphere| live vegetation| litter and coarse woody debris| and soil. Fluxes are represented as transfer between these pools that occur as a result of land use change| disturbance or recovery from past disturbance by plant growth and accumulation of organic matter. To estimate ecosystem areas| we used and adapted the most recently completed and current vegetation map available (Stone et al. in press). The primary sources for C density data were a report compiled by Olson et al (1983) and a subsequent version. We also used an alternative C density for closed moist forest from Brown and Lugo (1992). These forests play a major role in Brazil's C balance| but there is some uncertainty regarding their C density. We attempted to bracket this uncertainty by using both high and low values. We also used published data to calculate flux estimates. A major flux in Brazil's C budget is release to the atmphere resulting from deforestation. In 1990| 1.38 x 10(6) ha of closed forest were cleared in Brazil. Additionally| about 1.0 x 10(6) ha of cerrado woodland also cleared. We also estimated that 0.35 x 10(6) ha of secondary forest were cleared that year. Total C releases for the country as a whole were 174 - 233 x 10(6) tc/yr. The difference was caused mostly by differing estimates in the C density of closed tropical moist forests| which resulted in different fluxes from deforestation and burning. Net changes in pool sizes of our C budget model varied. The total vegetation C pool decreased by 160 - 240 x 10(6) tc/yr. The soil pool also lost C| about 80 x 10(6) tc/yr as a result of disturbance from forest clearing and intensive agriculture. However| the litter/coarse woody debris pool increased by 70 - 90 x 10(6) tc/yr. This increase was due to transfers from the vegetation pool due to clearing of closed tropical moist forest. Total gross C uptake by the system was 100 x 10(6) tc/yr of which 60 x 10(6) was addition to litter and soil pools in secondary forets. Total C releases were 120 - 150 x 10(6) tC/yr from deforestatio/burning and 150 - 180 x 10(6) tC/yr from decomposition. Most of the C released from burning was derived from above-ground vegetation but a significant amount also came form litter and coarse woody debris| including from reburning of residual logs and pastures. 4473,1995,3,3,BREAKING EVEN WITH GAS - AN UPDATE ON FUEL SWITCHING CALCULATIONS,A life cycle analysis approach is employed to determine the combined potential global warming impacts of carbon dioxide| methane and nitrous oxide emissions arising from the production| supply and use of coal| oil and natural gas in the United Kingdom. The study pays particular attention to recurring claims that the methane emissions associated with gas industry activities are removing the inherent low carbon advantage of natural gas. The results illustrate that natural gas maintains a clear lead as the least impacting fossil fuel and further demonstrates that the higher utilisation efficiency that natural gas maintains over coal and oil systems in many industrial| commercial and domestic applications| increases those advantages still further. 4423,1995,2,4,Can disturbance determine vegetation distribution during climate warming? A boreal test,Models of terrestrial vegetation distribution change during warming have generally paid little attention to ecological disturbances such as fire| even though these have been shown to be vitally important. A model predicting regionally dominant terrestrial vegetation in catastrophically disturbed landscapes is proposed: probability of a disturbance adapted species leaving progeny (P-r) is (1-1/M)(j)-(1-1/M)(s)| where M is the mean return interval between disturbances| j is the age of organisms at onset of reproduction| and s is the age at which reproduction ceases. For non disturbance-adapted species| the model simplifies to (1-1/M)(j). The model was tested in fire-prone boreal forest landscapes in Ontario| Canada (48 degrees 00'-52 degrees 00'N| 80 degrees 00'-95 degrees 30'W). A vegetation map whose classes and class geographical distributions were predicted using the above model was compared with a standard vegetation map. Three upland vegetation classes: poplar-pine| spruce-pine-poplar and spruce-fir were predicted| as well as an organic class representing non fire-prone vegetation on peat. These classes were almost the same as those in the standard map and the vegetation distribution was comparable (vegetation correctly predicted for 61.4% of the area| chi square P < 0.005). Thus the model can predict dominant vegetation in this system| implying that the distribution of boreal biome subzones in central Canada is largely governed by fire occurrence. To predict climate warming impacts| fire in the model was increased to 1.5 and 5 times the 1926-75 area| with a resultant shift of predicted vegetation zones to the north and east. 4318,1995,2,3,CARBON BALANCE IN THE TUNDRA| BOREAL FOREST AND HUMID TROPICAL FOREST DURING CLIMATE-CHANGE - SCALING-UP FROM LEAF PHYSIOLOGY AND SOIL CARBON DYNAMICS,Carbon exchange by the terrestrial biosphere is thought to have changed since pre-industrial times in response to increasing concentrations of atmospheric CO2 and variations (anomalies) in inter-annual air temperatures| How ever| the magnitude of this response| particularly that of various ecosystem types (biomes)| is uncertain| Terrestrial carbon models can be used to estimate the direction and size of the terrestrial responses expected| providing that these models have a reasonable theoretical base| We formulated a general model of ecosystem carbon fluxes by linking a process-based canopy photosynthesis model to the Rothamsted soil carbon model for biomes that are not significantly affected by water limitation| The difference between net primary production (NPP) and heterotrophic soil respiration (R(h)) represents net ecosystem production (NEP)| The model includes (i) multiple compartments for carbon storage in vegetation and soil organic matter| (ii) the effects of seasonal changes in environmental parameters on annual NEP| and (iii) the effects of inter-annual temperature variations on annual NEP| Past| present and projected changes in atmospheric CO2 concentration and surface air temperature (at different latitudes) were analysed for their effects on annual NEP in tundra| boreal forest and humid tropical forest biomes| In all three biomes| annual NEP was predicted to increase with CO2 concentration but to decrease with warming| As CO2 concentrations and temperatures rise| the positive carbon gains through increased NPP are often outweighed by losses through increased R(h)| particularly at high latitudes where global warming has been (and is expected to be) most severe. We calculated that| several times during the past 140 years| both the tundra and boreal forest biomes have switched between being carbon sources (annual NEP negative) and being carbon sinks (annual NEP positive)| Most recently| significant warming at high latitudes during 1988 and 1990 caused the tundra and boreal forests to be net carbon sources| Humid tropical forests generally have been a carbon sink since 1960| These modelled responses of the various biomes are in agreement with other estimates from either field measurements or geochemical models| Under projected CO2 and temperature increases| the tundra and boreal forests will emit increasingly more carbon to the atmosphere while the humid tropical forest will continue to store carbon| Our analyses also indicate that the relative increase in the seasonal amplitude of the accumulated NEP within a year is about 0.14% year(-1) for boreal forests and 0.23% year(-1) in the tundra between 1960 and 1990. 4299,1995,3,3,Carbon dioxide emissions and global GDP,A positive relationship between carbon dioxide emissions| the most important greenhouse gas (GHG) implicated in global warming| and GDP is shown in this paper| examining per capita income and CO2 emissions of 137 countries across 21 years. It also appears that as per capita incomes accelerate across countries emissions increases| for the most part| tend to decelerate. It could be that higher income levels lead to increased demand for environmental protection. Only emissions reduction proposals that assure incomes will not be adversely affected| particularly those of less developed countries (LDCs)| will have any possibility of successful implementation. 2549,1995,3,4,CARBON MITIGATION SCENARIOS FOR MEXICAN FORESTS - METHODOLOGICAL CONSIDERATIONS AND RESULTS,This paper examines three future scenarios for carbon emissions and sequestration in Mexican forests. The first is a Reference scenario that incorporates low and high emission estimates derived from different assumptions of deforestation rates in Mexico; the second is a Policy scenario that incorporates seven carbon mitigation options for reducing future net car bon emissions from the forest sector; and the third is a Technical Potential scenario that shows the maximum technically-feasible carbon sequestration achievable in Mexican forests by the year 2030. A consistent method for estimating the net unit carbon sequestration associated with different carbon mitigation options in the forest sector provides the basis for estimating the carbon implications of the different scenarios. The study suggests that cumulative carbon sequestration ranges from 2.2 to 4.4 gigatons of cal bon (GtonC) by the year 2030| depending on the scenario. Realizing this carbon sequestration potential could significantly offset emissions from the energy sector. Management of native temperate and tropical forests| and restoration of degraded forest lands| particularly when linked to energy plantations| offer the most promising alternatives for carbon sequestration. 4455,1995,2,3,CARBON STORAGE IN FOREST SOILS,The amounts of carbon stored in soils and vegetation in Britain| and the potential of forestry to influence| whether soils act as sinks or sources| are discussed. Soils are estimated to contain c.22 X 10(9) t carbon| while the amount in vegetation including forests is only 115 X 10(6) t. Some 86 per cent of the soil carbon is present in pears and peaty-surfaced soils| mainly in north-west Britain. Soil carbon content is strongly related to climate and altitude. Conversion of lowland cultivated land to forest can result in carbon accumulation in soils| as it can following the planting of some uplands| but quantities appear to be small in relation to the amounts carbon released to the atmosphere through fossil fuel use. Forest felling may result in decreases in soil carbon store| due to soil disturbance and changes in microclimatic conditions| but several decades after reafforestation the carbon store may recover to near original levels. Shortening forest rotations may result in long-term declines in soil carbon store. The main concern is the potential for forestry to convert peats| which contain amounts of carbon equivalent to 100 years' fossil fuel use at 1988 levels and which are normally slow sinks for atmospheric carbon| into carbon sources returning it to the atmosphere. The possible impacts of forestry and global warming on rates of carbon loss from upland soils including peats are discussed. 4324,1995,2,4,CARBON-DIOXIDE AND TEMPERATURE EFFECTS ON PIMA COTTON DEVELOPMENT,Predicting plant responses to changing atmospheric CO2 and to the possible global warming are important concerns. Effects of CO2 on developmental events are poorly documented| as is the interaction of CO2 and other major climate variables on crop development. The objective of this experiment was to determine the effects of an altered CO2 environment and interactions of CO2 and temperature on pima cotton developmental rates. Pima cotton (Gossypium barbadense L. cv. S-6) was grown from seed in sun-lit plant growth chambers. Air temperatures were controlled from 20/12 to 40/32 degrees C (day/night) in 5-degree increments. Daytime CO2 was maintained at 350 or 700 mu L L(-1). In a second experiment| the temperature was maintained at 30/22 degrees C day/night and the plants were grown in 350| 450| or 700 mu L L(-1) CO2. Days required to develop nodes on the mainstem| days from emergence to first square| number of vegetative and fruiting branches| number of fruiting sites produced| number of bells and squares produced| and number of bells and squares retained by the plants were determined. Rates of mainstem node formation and the time required to produce the first square and first flower were not sensitive to atmospheric CO2| but were very sensitive to temperature. Prefruiting branch nodal positions required longer to develop than nodes with fruiting branches. Carbon dioxide levels did not affect the time required to produce nodes. Number of branches produced was sensitive to both temperature and CO2. The larger number of bells set on the lower branches of plants grown at high CO2 provided a larger sink for photosynthate than plants grown at low CO2. This may be the reason for the observed reduction in number of fruit at the upper nodes of high-CO2-grown plants. More bells and squares were produced and retained on plants grown in high-CO2 environments| except that none were produced in either CO2 environment at 40/32 degrees C. Our results indicate that high-temperature-tolerant cotton cultivars would be more productive in the present-day CO2 world| and they would be essential in the future if global temperature increases. 4407,1995,3,4,CARBONYL SULFIDE - NO REMEDY FOR GLOBAL WARMING,The enhancement of the stratospheric aerosol layer caused by the eruption of Mt. Pinatubo (June 15| 1991)| and the subsequent cooling of the earth's lower atmosphere [Dutton and Christy| 1992; Minnis et al.| 1993] shows that stratospheric aerosols can have a strong effect on the earth's climate. This supports the notion that the intentional enhancement of the stratospheric aerosol layer through increased carbonyl sulfide (OCS) emissions might be an effective means for counteracting global warming. Through the use of a one-dimensional photochemical model| we investigate what effect such a program might have on global average stratospheric ozone. In addition| we consider the impact of enhanced OCS emissions on rainwater acidity and on the overall health of both plants and animals. We find that while the warming produced by a single CO2 doubling (1 to 4-degrees-C) might be offset with ozone losses of less than 5%| any attempt to use carbonly sulfide as a permanent solution to global warming could result in depletion of global average ozone by 30% or more. We estimate that in order to achieve cooling of 4-degrees-C rainwater pH would fall to between 3.5 and 3.8. Finally| a 4-degrees-C cooling at the surface will require that ambient near ground OCS levels rise to above 10 ppmv which is probably greater than the safe exposure limit for humans. Thus| enhanced OCS emissions do not provide an environmentally acceptable solution to the problem of global warming. 2563,1995,2,4,CHANGES IN MINIMUM AND MAXIMUM TEMPERATURES AT THE PIC-DU-MIDI IN RELATION WITH HUMIDITY AND CLOUDINESS| 1882-1984,In an attempt to contribute to the investigation on a global climate change| a historical series of minimum and maximum temperature data at the Pic du Midi| a mountain observatory at 2862 m a.s.l. in the French Pyrenees| is updated after correction of a systematic deviation due to a relocation of the station in 1971. These data| which now cover the 1882-1984 period| are examined in parallel with humidity and cloud cover data for the same period. From the beginning to the end of this period| observations show that the mean night-time temperature has increased by 2.39 degrees C/100 yr while the mean daytime temperature has decreased by 0.50 degrees C/100 yr. In consequence| the mean annual diurnal temperature range has dropped by 36%/100 yr. The maximum seasonal decrease is 46%/100 yr in spring| Season-to-season and year-to-year inter-relationships between minimum temperature| maximum temperature| relative humidity and cloud cover suggest that the decrease in maximum temperature is related to a concomitant increase of 15%/100 yr in both relative humidity and cloud cover. 4352,1995,3,4,CLASS-I ISOCYANURATE FOAMS BLOWN WITH PENTANE,The transition from CFCs to HCFCs and zero ODP compounds| as mandated by CFC phaseout protocol| is well under way in most areas of urethane foam production. Specifically| the laminate board industry is in the process of converting to HCFC-141b as an intermediate solution to R-11 blown foams. The switch will serve the industry for the next few years. However| HCFCs also destroy ozone| and 141b is perhaps the strongest ozone depleter among HCFCs in current use. Consequently| 141b must eventually be replaced with a zero ODP alternative. Recently announced EPA recommendations call for cessation of both production and consumption of 141b by the year 2003 [1]. Therefore| current research is concentrated on developing effective| economical| zero ODP options for laminate board production. The task is large| however| due to the many requirements imposed on the product. Good k-factors and flame resistance are important. In the past| these requirements were met through both the isocyanurate structure of the foam and the low flammability and thermal conductivity of the blowing gas. BASF is currently investigating the use of hydrocarbons such as pentane as blowing agents for laminate board. Hydrocarbons are inexpensive| abundant liquids which have a zero ODP (ozone depletion potential) and a low GWP (global warming potential). We have produced laminate board foams with reasonable k-factors (0.135-0.146) and surprisingly good flame resistance using n-pentane| cyclopentane| and 2-chloropropane [2]. The good k-factors and improved flame resistance have been achieved through the use of such tools as increased index| use of phosphorous-containing polyols| and the addition of halogenated inerting agents. Our results to date indicate that with a proper combination of these techniques| potential Class I rated laminate board blown with hydrocarbons is possible. 2589,1995,5,4,Climate change and its impact on tropical montane ecosystems in southern India,The montane regions (>2000 m MSL) of the Western Ghats in southern India feature stunted evergreen forests (C3 plant type) interspersed with extensive grasslands (C3 or C4 plant types). We have studied the vegetational history of this ecosystem in relation to climate change during the late Quaternary through stable-carbon isotope analysis of peat deposits as indicators of C3 or C4 plant types. Grasslands (of C4 type) were predominant during the last glacial maximum (20-18 kyr sp) and again during 6-3.5 kyr sp| while forest and possibly C3 grassland expanded during the deglaciation| attaining their peak distribution at 10 kyr sp. The shift in C3 and C4 plant types seems related to changes in moisture and atmospheric CO2| with lower moisture and CO2 levels favouring the latter plant types. The oscillating climate and vegetation has influenced the structure and composition of the montane ecosystem. Plant diversity of the near-pristine montane forests is relatively lower than other comparable sites in the neotropics. The implications of global change on the tropical montane ecosystem| in particular the composition of the angiosperm and vertebrate communities| are discussed. In particular| an expansion of montane forest and replacement of C4 with C3 grassland can be expected. Human impact on the natural vegetation| such as conversion of grasslands to monoculture plantations of wattle and eucalypts may| however| interfere with natural succession caused by global climate change. Endemic mammals such as the Nilgiri tahr would face increased risk of extinction. 4333,1995,4,1,CLIMATE RESPONSE TO INCREASING LEVELS OF GREENHOUSE GASES AND SULFATE AEROSOLS,CLIMATE models suggest that increases in greenhouse-gas concentrations in the atmosphere should have produced a larger global mean warming than has been observed in recent decades| unless the climate is less sensitive than is predicted by the present generation of coupled general circulation models(1|2). After greenhouse gases| sulphate aerosols probably exert the next largest anthropogenic radiative forcing of the atmosphere(3)| but their influence on global mean warming has not been assessed using such models| Here me use a coupled ocean-atmosphere general circulation model to simulate past and future climate since the beginning of the near-global instrumental surface-temperature record(4)| and include the effects of the scattering of radiation by sulphate aerosols| The inclusion of sulphate aerosols significantly improves the agreement with observed global mean and large-scale patterns of temperature in recent decades| although the improvement in simulations of specific regions is equivocal| We predict a future global mean warming of 0.3 K per decade for greenhouse gases alone| or 0.2 K per decade with sulphate aerosol forcing included| By 2050| all land areas have warmed in our simulations| despite strong negative radiative forcing in some regions. These model results suggest that global warming could accelerate as greenhouse-gas forcing begins to dominate over sulphate aerosol forcing. 4323,1995,4,3,CLIMATE RESPONSE TO RADIATIVE FORCINGS BY SULFATE AEROSOLS AND GREENHOUSE GASES,The annual| global mean radiative forcing for the troposphere-surface system has been used to rank the global warming influences of atmospheric trace gases. The approach was also used recently to compare the cooling influence of tropospheric sulfate aerosols with the warming influence of greenhouse gases. However| the spatial inhomogeneity of sulfate aerosols (concentrated mainly in the continental Northern Hemisphere) may induce climate responses which differ other than just in sign from those induced by increased concentrations of the more homogeneously distributed greenhouse gases. Here we use a general circulation model to further examine the suitability of global mean radiative forcing as a predictor of differences in global| hemispheric| and regional climate responses to differing spatial and temporal forcing patterns. The calculated responses indicate that changes of the global and annual mean surface air temperature depend only on global average net forcing and are not highly sensitive either to the details of the spatial and seasonal patterns in forcing or to the nature of the forcing (shortwave vs. longwave). Thus in global and annual mean the negative aerosol forcing may be viewed as a scaleable anti-greenhouse forcing. However substantial responses to nonuniformly distributed aerosol forcing were observed at hemispheric and regional scales. Further| the patterns of response differ from the patterns of forcing| leading to the conclusion that the spatial distribution of all significant forcings must be accurately represented when studying regional climate changes. 4335,1995,2,4,CLIMATE VARIABILITY AND AGROECOLOGICAL CHANGE IN THE CENTRAL PAMPAS OF ARGENTINA,Global warming is likely to alter natural and agricultural ecosystems| probably causing relocation of some of the major crop-producing regions| and a change in the geographic distribution of rangelands and forests. More important than the direct effect of the temperature increase| would be any alteration in the rainfall pattern in those many regions where rainfall limits crop production. The purpose of this work| which focuses on a traditional| semi-arid| cattle-cereal crop production area in the Central Pampas of Argentina| was to study structural and functional changes in this agroecosystem in response to the measured climate variability over a 30 year period| 1960-1990. Using long-term data| correlation analysis was used to estimate the degree of association between changes in the land use pattern on the one hand| and changes in rainfall| grain price and crop yield on the other hand. Crop yield was the result of an interaction between climatic and technological factors. The analysis also Linked climate variability with key agroecological factors such as hydrology| energy flow| and soil nitrogen balance. The results showed that changes in land use were highly correlated with the yield of crops| less correlated with rainfall| and poorly associated with crop grain prices. A positive correlation between the annual rainfall and the relative increase of the crop area was found for all districts analyzed. This change could largely explain the increased energy flow as well as nitrogen loss in the agroecosystem studied. Consequently| land use strategies should be considered with caution| especially during favorable climatic period in semi-arid environments. The same conditions that favor grain harvesting in these environments| may also set at risk the sustainability of a long-term| low-input agriculture. 4427,1995,2,4,CLIMATE| COPEPODS AND COD - SOME THOUGHTS ON THE LONG-RANGE PROSPECTS FOR A SUSTAINABLE NORTHERN COD FISHERY,Cod Gadus morhua stocks on the Labrador Shelf and Grand Banks| NW Atlantic| are apparently at an all-time low. While overfishing has undoubtedly occurred| it is probable that other factors are affecting stock recruitment as well. Water temperatures and salinity are also unusually low| which may have affected the abundance of cod in some way. Northern cod begin spawning in March in most stock management zones around Newfoundland| Canada. First-feeding cod larvae survive in waters less than 2 degrees C but require suitable prey| especially nauplii of the copepod Calanus finmarchicus| to grow well. The 'match/mismatch' hypothesis assumes that cod spawn at the same time each year| but spawning by copepods may or may not 'match' depending on the stimulus provided by the 'spring bloom' of phytoplankton| which can vary with environmental conditions by up to 6 wk. While C. finmarchicus is common in the Atlantic waters of the Labrador Sea and Grand Banks| zooplankton in the Labrador Current| especially during this period of low temperature and salinity| are dominated by 2 arctic copepods| C| glacialis and C| hyperboreus| which have different spawning seasons| and therefore probably would not provide a good nutritional match for young cod. Despite global warming| sea water supporting important demersal fish on the continental shelf off northeast Canada is presently colder and fresher than normal. Global warming may have induced melting of glaciers and sea ice and increased runoff in rivers entering the Arctic Ocean and its coastal drainage| reducing salinity at the sea surface| increasing stability and reducing deep convection| and hence upward heat transport. Several cold| fresh 'anomalies' have been observed in the last few decades and they have contributed to less favourable conditions at locations around the North Atlantic. These anomalies may be part of an interdecadal climate cycle of alternating warm and cold periods| the effects of which must be removed to clearly identify those associated with global warming. Whatever the causes| periods of 'ocean cooling'| with potentially serious consequences for the cod fishery| may be predictable. Increasing amounts of ice in the eastern Arctic and Greenland Sea are easily monitored by satellite and appear to anticipate reduced temperature/salinity anomalies in the Labrador Sea by about 4 yr. Climatic impacts| whether cyclic or continuing| could be identified sufficiently far in advance to enable modifications in management of the fishery toward at least mollifying their effects| thus improving the prospects for long-term sustainability. 4315,1995,2,4,CLIMATE-CHANGE AND AGRICULTURE - AN INDIAN PERSPECTIVE,In this paper| we examine the major predictions made so far regarding the nature of climate change and its impacts on our region in the light of the known errors of the set of models and the observations over this century. The major predictions of the climate models about the impact of increased concentration of greenhouse gases ave at variance with the observations over the Indian region during the last century characterized by such increases and global warming. It is important to note that as far as the Indian region is concerned| the impact of year-to-year variation of the monsoon will continue to be dominant over longer period changes even in the presence of global warming. Recent studies have also brought out the uncertainties in the yields simulated by crop models. It is suggested that a deeper understanding of the links between climate and agricultural productivity is essential for generating reliable predictions of impact of climate change. Such an insight is also required for identifying cropping patterns and management practices which are tailored for sustained maximum yield in the face of the vagaries of the monsoon. 2571,1995,2,4,CLIMATE-CHANGE AND VECTOR-BORNE DISEASES - A GLOBAL MODELING PERSPECTIVE,GCM-based scenarios of anthropogenic global climate change are used for the assessment of potential changes in areas vulnerable to malaria and schistosomiasis transmission. The study shows that the transmission potential of both vector-borne diseases is very sensitive to climate changes on the periphery of the present endemic areas and at higher altitudes within these areas. The health impact will be most pronounced in populations living in the less economically developed temperate areas in which endemicity is low or absent. 4360,1995,3,3,CO2 FIXATION AND OIL PRODUCTION THROUGH MICROALGA,As one way to prevent global warming due to carbon dioxide| microalgal oil production with secondarily treated sewage (STS) and thermochemical oil recovery from algal cells were studied. A hydrocarbon-rich microalga| Botryococcus braunii| produced hydrocarbons and consumed nitrate and phosphate in STS. Removal effects of the alga regarding As| Cd and Cr were observed during these experiments with an artificial medium. As for oil recovery from algal cells| the maximum yield of oil obtained by liquefaction was 64 wt% on a dry basis at 300 degrees C with a catalyst of sodium carbonate. 4359,1995,3,3,COGENERATION CONCEPTS FOR CO2 SEPARATION FROM POWER-PLANTS FOR ENHANCED OIL-RECOVERY APPLICATIONS,A large amount of carbon dioxide (CO2) is being produced from fossil fuel fired power plants and discharged into the atmosphere annually. As a result| the discharged CO2 is now suspected to have caused the greenhouse effect and global warming problem. To overcome this CO2 emission problem| there is great interest| especially in Canada| to capture carbon dioxide and utilize it as a flooding agent for the enhanced oil recovery (EOR) process. In the past few years| a number of feasibility studies and a few testing pilot projects on CO2 extraction from power plants were performed. However| their results have showed that even though it is technically feasible to extract CO2 from power plants| its cost is high for the EOR application in the current crude petroleum market. A major reason for the high cost is that the CO2 extracting process requires a substantial amount of energy. This paper demonstrates how cogeneration concepts together with optimization design strategies would help to reduce the CO2 production cost by utilizing low-pressure steams and waste-heats from various sections of the power generation processes for extracting CO2. The economics and technical feasibilities of these concepts are described and the practical implications given Western Canada's resources for EOR applications are discussed. 4388,1995,4,4,COMMENTS ON CLIMATE-CHANGE SCENARIO DEVELOPMENT,A short review is presented of progress in climate change scenario development. Sources of uncertainty are discussed. Critical assessment of climate models for their veracity in describing the present climate is considered essential. Methods of deriving sub-continental scale patterns of climate change| per degree of global warming| include the use of finer resolution global models| nested modelling| and spatial interpolation. Transient effects and the importance of extreme events are also discussed. 2591,1995,2,4,Comparative response on gas exchange of Picea spp exposed to increased atmospheric CO2 in open top chambers at two test sites,We took comparative measurements of gas exchange response curves of two species of spruce (Picea abies (L.) Karst and Picea sitchensis (Bong.) Carr.) exposed to high levels of atmospheric carbon dioxide (CO2) in two test stations: Vielsalm (Belgium) and Glendevon (United Kingdom). The photosynthetic response of these two species to variations in concentrations of intercellular CO2 and to variations in light intensity were measured in situ using an integrated transportable differential CO2 and water vapour exchange measuring system. The response curves were adjusted by the Mitscherlich function. The statistical analysis of our measurements and adjustments reveal similarities in the reaction of Picea abies and Picea sitchensis to a doubling of the present level of atmospheric CO2. Regarding the photosynthesis response curves to intercellular CO2 variation| we noted a decrease in the maximum photosynthesis rate and the carboxylation rate accompanied by an increased compensation point. Regarding the photosynthesis response curves to the light variation| we found that dark respiration and photochemical efficiency remained unchanged| and the maximum photosynthesis rate was slightly higher in an atmosphere enriched in CO2. These experimental contexts would seem to indicate that the current and forecast levels of CO2 are not ecological factors limiting primary productivity| and that the increase in atmospheric CO2 interacts with other environmental factors. 4453,1995,2,3,COMPARISON OF 5 WHEAT SIMULATION-MODELS IN SOUTHERN ALBERTA,Increasing concentrations of greenhouse gases are expected to result in global warming which will affect crop production. Crop modelling is a useful tool for assessing the impact of climate change on crop production. The objective of this study was to select an appropriate model for climate change studies. Five simulation models| EPIC| CERES| Century| Sinclair and Stewart| were assessed using data from a long-term experiment begun in 1911 on a day loam (Dark Brown Chernozem) soil at Lethbridge| AB. Yields predicted by the five models were compared with actual spring wheat yields in continuous wheat| fallow-wheat and fallow-wheat-wheat rotations. The EPIC model gave the best simulation results over all rotations and the most accurate predictions of mean yields during droughts. It was concluded that the EPIC model had the greatest potential for assessing the impact of climate change on wheat yield. The Stewart model was the most accurate for unfertilized continuous wheat and fallow-wheat. The Sinclair model was most accurate for fertilized fallow-wheat and CERES was the most accurate model for fertilized continuous wheat. The Century model simulated average yield accurately but did not account for year-to-year variability. 4442,1995,3,2,COMPARISON OF CHEMICAL SOLVENTS FOR MITIGATING CO2 EMISSIONS FROM COAL-FIRED POWER-PLANTS,There is a growing concern about the effect of greenhouse gases on global warming. Among the many greenhouse gases| CO2 produced from burning fossil fuels is a major contributor due to the huge volumes emitted into the atmosphere. According to the estimates of the Intergovernmental Panel on Climate Change (IPCC)| a worldwide reduction in the emission of greenhouse gases by more than 60% is necessary to avert significant global climate changes. This paper examines the key issues involved in greenhouse gas emissions from coal-fired power plants. At the present time| absorption by chemical solvents appears to be the best option for the separation of CO2 from low pressure flue gas streams. The costs of separation and disposal of CO2 from existing coal fired| air blown boilers are estimated to increase the cost of electricity by about 75%. Therefore| there is a need to optimize the selection of processing solvents and operating parameters to minimize the cost of separation. Increasing the inlet flue gas pressure did not improve mass transfer rates sufficiently to compensate for the higher compression costs. The effects of other process variables were also examined. In this work| we have examined the cost effectiveness of six ethanolamine-based solvents. Overall| monoethanolamine (MEA) was found to be the best solvent. 4448,1995,2,3,CONTAMINANTS AFFECTING THE ARCTIC CLIMATE| AND THE ROLE OF THE OCEANS,We are increasingly impressed with the idea that the climate system must be treated globally| and| by the same token| most contaminants affecting the Arctic and its climate have global origins. This is manifestly true of carbon dioxide and its influence on surface temperature through the greenhouse effect| and of chlorofluorocarbons that affect both the surface temperature and stratospheric ozone. In both of these cases| the response of the Arctic is more dramatic than that in the lower latitudes. Another type of contaminant that affects the Arctic climate in the springtime is the light-absorbing aerosols transported northward from industrial regions. Moreover| the Arctic includes several unique regional climatic feedback mechanisms| such as the effect that a global warming can have on the release of carbon dioxide and methane locked in the tundra and taiga (probably a positive feedback)| and the effect of shrinking sea ice and snowcover on the heat balance of the hemisphere (definitely a positive feedback). It has long been recognized that changes in ocean circulations| notably in the North Atlantic and Greenland Sea| can have a dominant effect on regional and global temperatures. All of these effects are unfortunately poorly treated in current climate and ecosystem models| and this introduces an element of uncertainty in predictions of global warming and the fate of contaminants in the Arctic. 2601,1995,3,3,COPATH - A spreadsheet model for the estimation of carbon flows associated with the use of forest resources,The forest sector plays a key role in the global climate change process. A significant amount of net greenhouse gas emissions emanate from landuse changes| and the sector offers a unique opportunity to sequester carbon in vegetation| detritus| soils and forest products. However| the estimates of carbon flows associated with the use of forest resources have been quite imprecise. This paper describes a methodological framework-COPATH-which is a spreadsheet model for estimating carbon emissions and sequestration from deforestation and harvesting of forests. The model has two parts| the first estimates carbon stocks| emissions and uptake in the base year| while the second part forecasts future emissions and the uptake under various scenarios. The forecast module is structured after the main modes of forest conversion| i.e. agriculture| pasture| forest harvesting and other land uses. The model can be used by countries which may not possess an abundance of pertinent data| and allows for the use of forest inventory data to estimate carbon stocks. The choice of the most likely scenario procides the country with a carbon flux profile necessary to formulate GHG mitigation strategies. 4382,1995,2,4,CORRELATION OF ICE LOAD WITH LARGE-SCALE AND LOCAL METEOROLOGICAL CONDITIONS IN HUNGARY,Conditional probability of icing in correlation with local weather elements| as well as with different macrocirculation types are investigated on the basis of 23 years of daily observations for two stations situated in the Pannonian Plain (Debrecen) and in mountainous region (Kekesteto| 1000 m above sea-level). Empirical histograms are calculated and a theoretical model of the distribution is elaborated. Ice is generally twice as frequent at night as during the day. Icing is 5-6 times as frequent on the top of the hill as on the plain| especially considering larger water-contents. Macrosynoptic conditions favourable for icing are essentially different in the two circumstances. At the higher altitude icing is more frequent in cyclonic situations. Considerable load is often accompanied with southwesterly| southerly currents. On the plain station however the anticyclonic situations are somewhat more frequently accompanied with ice formation. Wind speed is practically indifferent at the top of the hill| but on the plain ice formation prefers low wind speeds. These differences are in coincidence with the a priori information of the different nature of ice load. Namely| at the top of hill in-cloud icing is the predominant form| while on the plain fine rime and frozen precipitation represent the overwhelming majority of ice load events. No clear differences in probabilities of icing in any of the above relations appear| however| between the two perpendicular directions of measuring devices. From among the possible applications of the results| a local scenario on ice load changes assuming a 0.5 K global warming is presented. 4303,1995,3,3,CREATING A GLOBAL WARMING IMPLEMENTATION REGIME,This paper proposes a global warming implementation regime which addresses the issues of equity| flexibility| cost minimization| and population growth. Previously proposed international policy instruments| such as country by country targets| carbon taxes| and tradable permits| face major difficulties as stand alone proposals. The key element of the regime proposed here is to combine annual tradable permits which are allocated based on population in a fixed year with a small carbon tax ($5-10/tonne) on emissions in excess of permits. Both permits and carbon taxes are applied to national level governments| which in turn would use whatever mix of policies desired to reduce national emissions. It is suggested that the initial number of permits correspond to total global emissions in the base year; over time| the number of permits could be reduced and the tax rate increased if improved scientific knowledge so dictates. By allocating permits based on population the equity concerns of developing countries are addressed| while taxing emissions in excess of permit holdings removes the rigidity of a quota system and limits resource transfers by effectively capping the permit trading price| which is a major concern of industrialized countries. To accommodate the difficulties of countries which have not yet achieved the demographic transition| the permit allocation scheme could be subject to a one-time adjustment after 10-15 years based on some weighting of the initial and then-current populations. The proposed scheme is based on the premise that there is a large potential for reducing emissions in developed countries or limiting emission increases in developing countries| and the intention is to create competition between national level governments in implementing cost-effective emission reduction. 4330,1995,2,3,Curbing coastal erosion - Example of Udvada (South Gujarat),An impending threat to our coastline is through the green house effect and the consequent rise in the sea-level. However| long before began the talk of global warming several of our shorelines came under the assault of the advancing sea. One of the glaring examples is of the settlement of Udvada in South Gujarat housing the oldest Fire Temple of the Parsis. The first onslaught occurred nearly five decades ago and gradually the beach has been eroding. Horizontal walls have not proved very effective IVT) doped with chromium oxide have been determined by A two pronged attack envisages protecting the beach by raising plantations of suitable species (Casuarina| Agave Ipomoea) to bind the sand| to serve as shelter belt preventing the salt spray from invading fertile land in the interior| reducing the salinity of well-water and soil (through back- mangrove species of economic importance like Salvadora). In a location facing acute fuelwood shortage| alternative energy plantations of fast growing species like Acacia holosericea will provide fire-wood for the weaker sections of the society| sparing the trees raised for the protection of the shorelines. Sloping| permeable walls and sand injection are alternatives on the engineering side. Understanding the problem from geomorphological angle is the first necessity. The experiment of combating sea-erosion launched by the Bombay based SAVE UDVADA Committee with support of the Central and State (Gujarat) Governments will lay a foundation for restoration work elsewhere in the country. 4379,1995,2,4,DEALING WITH ERROR IN SPATIAL DATABASES - A SIMPLE CASE-STUDY,There is now a considerable body of literature on the techniques available for modeling and communicating error in spatial databases. Some error models have solid statistical foundations| while the basis for others is nor so strong. In this paper| three basic approaches to the problem are examined. The application investigated is a fundamental one-to determine the position of a given terrain elevation value and to portray the resultant error of the answer. Such a problem can be of critical concern to communities in cases of flood plain mapping| determination of rising sea levels resulting from global warming| or delineation of the full supply level for a proposed reservoir. In this instance| the authors suggest that the application of simple probability theory| when combined with the error estimates supplied by data producers and current computer graphics capabilities| can provide users with more meaningful information concerning the error of their spatial database products. In turn| this information may allow them to better deal with an issue of growing concern. 4475,1995,3,3,DEVELOPMENT OF MICROCELLULAR OPEN CELL RIGID POLYURETHANE FOAMS,With the increasing concern over the threat of ozone depletion and global warming| the rigid polyurethane foam insulation industry is facing a major challenge of selecting alternatives for chlorofluorocarbons (CFCs). Under the present situation| however| the effective means of solving this problem haven't been taken yet. Moreover| with more concern with the saving of energy worldwide| there is hope of insulators with higher performance. This paper reports on a micro cellular open cell polyurethane foam| which is very effective as a core material for evacuated insulators. In addition| thermal insulation panels with high performance are developed by utilizing the open cell foam as a core material. The evacuated insulators| so-called ''vacuum insulation panels|'' have an insulation effectiveness four times better than those of the conventional rigid polyurethane and polyisocyanurate foams (thermal conductivity is 0.005 W/mK) and are also very lightweight compared to those made of inorganic substances such as silica powder. The vacuum insulation panels were manufactured by packing the core material and absorbents in a film-like laminated plastic container| which is suitable for holding a vacuum| followed by sealing in the industrial vacuum level (0.01 approximately 0.1 mm Hg). We have developed the micro cellular (100 approximately 200 mum) and 100% open cell foam by selecting polyol compositions| modified polyisocyanates| surfactants and cell opening additives. The micro cellular open cell foam has excellent physical properties such as heat resistance| compressive strength and low shrinkage as well as non-scorch at the stage of slabstock foaming. These properties will be very important for manufacturing the vacuum insulation panels. The open cell foams were blown by using the most conventional and alternative blowing agents in rigid foam systems. In the near future| we hope that this open cell foam technology will contribute to the development of environmentally friendly and high performance products in the insulation industry. 4296,1995,2,4,Documenting and detecting long-term precipitation trends: Where we are and what should be done,A brief review of problems and achievements in documenting precipitation changes during the period of instrumental measurements is presented. Concern is expressed that without appropriate studies in the coming period of a new generation of precipitation measurements| technological progress in instrumentation may adversely and inadvertently affect our capability for monitoring and detecting future changes in terrestrial precipitation. At the same time| only a new generation of instrumentation will be capable of resolving the problems of monitoring precipitation over oceans. Special attention is paid to validation of the increasing trend in terrestrial precipitation observed during the past hundred years at high latitudes of the northern hemisphere - a feature of global warming predicted by most climate models. 4307,1995,4,5,DYNAMIC CONTRIBUTION TO HEMISPHERIC MEAN TEMPERATURE TRENDS,On the basis of land station data from the Northern Hemisphere| it was determined that roughly half of the temporal variance of monthly mean hemispheric mean anomalies in surface air temperature during the period from 1900 through 1990 were linearly related to the amplitude of a distinctive spatial pattern in which the oceans are anomalously cold and the continents are anomalously warm poleward of 40 degrees north when the hemisphere is warm. Apart from an upward trend since 1975| to which El Nino has contributed| the amplitude time series associated with this pattern resembles seasonally dependent white noise. It is argued that the variability associated with this pattern is dynamically induced and is not necessarily an integral part of the fingerprint of global warming. 2576,1995,2,2,ECOLOGICAL STABILITY OF FORESTS AND SUSTAINABLE SILVICULTURE,The ecological stability of forests is described and subsequently analyzed and discussed in relation to human impact. Forest management and utilization have a considerable influence on the stability and sustainability of forest ecosystems. Additionally| other human activities such as pollution and global climate change affect the present and future stability of our forests. The main components of stability are resistance (inertia| immovability) and resilience (recoverability). These are analyzed with respect to genetic diversity within and between species and in relation to the biogeochemical cycle. The possibilities and constraints of silviculture are then discussed in relation to sustainable management practices and strategies| i.e. choice of provenances and species| including species mixtures| tree breeding| harvesting practices| as well as the silvicultural system applied. Finally| forest decline is discussed in relation to stability by means of a stress integration model. 4472,1995,3,2,ECONOMICS OF A GLOBAL STRATEGY FOR REDUCTION OF CARBON EMISSIONS,The evolution of natural systems that feed and sustain human populations| and indeed the evolution of modern society| has occurred in the context of a moderate and stable climate. Therefore| recent trends in climate change| most likely caused by increasing concentrations of carbon dioxide and other radiative trace gases in the atmosphere| and the expected consequent global warming| are now a major concern. Carbon emissions from energy systems are considered one of the major contributors to climate change and are the focus of all studies on the prevention of climate changes and adaptation strategies. Two global energy scenarios (each with several options) are analysed in this paper: from a dynamic-as-usual concept to a more advanced concept with the goal of stabilizing carbon dioxide concentrations in the atmosphere (equivalent to about a 60% reduction of carbon emission compared with today's level)| It is shown that the stabilization approach will require dramatic changes in energy systems: the share of non-carbon fuels will increase to about three quarters of the total primary energy consumption| which will itself grow by a factor of two by the middle of the next century. Surprisingly| the implementation costs turn out to be approximately the same for all scenarios (taking into account possible errors in the cost appraisals for several decades ahead). However| the cost distributions between energy production and use are quite different. Globally| these costs are 3-4% of the GNP| but for developing countries the share of energy investments is| on average| about 7-8% of the GNP| which is cause for concern and will greatly hamper economic and social progress in the Third World. The introduction of energy taxes or carbon taxes in developed countries and the raising of 'global energy funds' could help developing countries to overcome these difficulties. It is supposed that such a policy would stimulate economic growth in developing countries and| as a feedback| overlap the GNP losses in developed countries. The paper attempts to evaluate an optimal strategy for reducing carbon emissions for the next couple of decades| when large uncertainties surround global warming| and to show ways of establishing 'no-regret' policy. 4364,1995,3,3,ECOSYSTEM DRIVEN BY OTEC AND OCEANIC HIGH MINERAL-WATER - OTOHIME PROJECT,A new system is proposed for mitigating global warming using a high productivity of coral reef ecosystems and ocean thermal energy conversion systems (OTEC) The system is called ''Otohime''. Deep sea water is fed to a coral reef of 100km(2) at a feeding rate of 3.1 X 10(5)m(3)/h| electricity of 25MW is generated| CO2 of 5.8 X 10(4)t-C/y is fixed| and furthermore global temperature can be reduced by 4 X 10(-6)degrees C. 4319,1995,3,4,EFFECT OF FLUCTUATION OF SURFACE SEA-WATER TEMPERATURE AND AMBIENT-PRESSURE ON EVAPORATION RATE OF EVAPORATOR IN BAROMETRIC TYPE OC-OTEC SYSTEM,Global environmental problems| such as global warming and the effects of acid rain| are expected to become more serious in the future. One methodology for solving this problem uses harmless energy resources. Ocean energy is one of such energy resources. This research involves a study of the OC-OTEC system| which is one type of ocean thermal energy conversion technology. In this system| the steam that drives a turbine is generated in an evaporator and condenses in a condenser after passing through a turbine. However| the steam evaporating rate in an evaporator is affected by the fluctuations of surface sea water temperature and ambient pressure. Therefore| it is necessary to define the dynamic characteristics of the evaporator in order to gain constant power output. This paper presents an analysis as to how evaporation rate is affected when surface sea water temperature and ambient pressure change. Further| we clarify that the dynamic characteristics of the evaporator are more affected by fluctuations in the ambient pressure than in surface sea water temperature. 4337,1995,2,4,Effect of monocropping on maize yield on meadow soil in long-term fertilization experiments,The yield changes' of maize produced in crop-rotation and monoculture were studied on the basis of data collected from filed experiments on meadow soil. The experiments are part of the National Long-Term Fertilization Experiment started in 1966. Applied crop-rotations in the experiment: a) triculture: pea - wheat - maize - maize; b) biculture: wheat - maize - wheat; c) monoculture: since 1966. The soil characteristics of the experiments are: difficult tillage| slow mineralization of N in the springtime and considerable absorption of P| K. The study covers the period between 1982-1993. I present the amounts of the yearly precipitation (Table 1.) and precipitation fallen in the vegetation period of maize compared to the average. Heavy drought occurred in 1982-83-86-90-93. During the examined 12 years the precipitation was 1600.7 mm less than the 50-years average. Because of the global warming half of the examined years were droughty. Maize can tolerate the partial monoculture considerably well| but after 10-15 years of monocropping the yield decreases by 1-3 t/ha in droughty years compared to the yields achieved in crop rotation. Monocultural maize yields decreased significanty in 1983|'90|'92|'93. The best forecrop for maize was the wheat. The forecrop influences the requierement for fertilizer. The best yields were obtained as follows: after wheat in triculture (pea-wheat-maize) with a dose of 50-60 kg/ha N| in biculture (wheat-maize) with a dose of 60-80 kg/ha N| after maize in biculture with a dose of 80-100 kg/ha N| and in monoculture with a dose of 100-120 kg/ha N. In monoculture cropping the number of bacteria in the soil decreased significantly. The number of bacteria in 1 g soil was 59 million after wheat| 285 million after maize| and only 16 million in monoculture cropping| which can effect the soil life considerably. In monoculture cropping the Zn content of the grain decreased by 4-5 mg/kg which can limit the yield or cause losses in nutritive value. The yield decrease of monocultural maize can be explained by the impoverishment of the soil water supply. Thus the monocropping of maize| particularly in areas with poor rainfall| must be placed into crop-rotation after 10-15 years of monoculture. The risk of monocropping should be decreased by using partial monoculture| a hybrid with good adaptability| 5-10 thousand less plant density per hectare and irrigation if the conditions are given. 4440,1995,2,4,EFFECTS OF A SUMMER TEMPERATURE REGIME REPRESENTATIVE OF A GLOBAL WARMING SCENARIO ON GROWTH AND PROTEIN-SYNTHESIS IN HARDWATER-ACCLIMATED AND SOFTWATER-ACCLIMATED JUVENILE RAINBOW-TROUT (ONCORHYNCHUS-MYKISS),1. Growth| appetite| gross conversion efficiency and protein turnover rates of liver| gills and white muscle were measured in juvenile rainbow trout chronically exposed (90 days) to soft and hardwater at two temperatures (ambient| ambient temp. +2 degrees C). The temperature regime followed that of inshore Lake Ontario over the months of June-September 1993 as temperature rose from similar to 13 to 24 degrees C. 2. Over the initial 60 days of exposure| the addition of 2 degrees C to the ambient temperature increased growth| appetite| gross conversion efficiency and protein turnover by an average of 16%. However| further exposure during the period of peak ambient temperatures| led to an average 20% reduction in growth| appetite| gross conversion efficiency and protein turnover. 3. Increased rates of gill protein turnover and arguably lower rates of growth indicate that the cost of living for a trout acclimated and maintained in synthetic softwater is higher than that of hardwater fish. In addition| lower appetite in softwater fish suggest that life in softwater is itself a mild form of environmental stress. 4429,1995,2,4,EFFECTS OF CLIMATIC-CHANGE ON TREES FROM COOL AND TEMPERATE REGIONS - AN ECOPHYSIOLOGICAL APPROACH TO MODELING OF BUD BURST PHENOLOGY,A framework is presented for meddling bud burst phenology of trees from the cool and temperate regions. Three ecophysiological aspects affecting the timing of bud burst are considered: (i) effects of environmental factors on the rest status of the bud| (ii) effect of rest status on the ability for bud burst| and (iii) direct effect of air temperature on the rate of development towards bud burst. Any model for bud burst phenology can be presented within the framework with three submodels| each of them addressing one of the corresponding three ecophysiological aspects. A total of 96 hypothetical models were synthesized by combining submodels presented in the literature. The models were tested in two experiments with saplings of Pinus sylvestris L. growing in experimental chambers at their natural site in eastern Finland. In the first experiment| air temperature and (or) concentration of atmospheric CO2 was elevated. Elevation of the air temperature hastened bud burst| whereas elevation of the concentration of CO2 did not affect it. Several models accurately predicted the timing of bud burst for natural conditions but too early for bud burst at the elevated temperatures. This finding suggests that (i) the risk of a premature bud burst with subsequent frost damage| as a result of climatic warming| was overestimated in a recent simulation study| and (ii) bud burst observations in natural conditions alone are not sufficient for the testing of these mechanistic models. Several models did predict the timing of bud burst accurately for all treatments| but none of them obtained sufficiently strong support from the findings to stand out as superior or uniquely correct. In the second experiment a photoperiod submodel for rest break was tested by exposing the saplings to short-day conditions. The short-day treatment had only a minor effect on the timing of bud burst. These results demonstrated the importance of the concept of model realism: the accuracy of a model can be lost in new conditions (e.g.| global warming)| unless the model correctly addresses the essential ecophysiological aspects of the regulation of timing of bud burst. 4316,1995,2,4,EFFECTS OF COLD AND WARM YEARS ON THE WATER CHEMISTRY AT THE BIRKENES CATCHMENT| NORWAY,During the last years| several scientists have been concerned with the consequences of global warming. In the Birkenes catchment| situated in southernmost Norway| several warm years have occurred during the last decade. In this climatic region| warm years primarily mean warmer winters with mean air temperatures close to or higher than 0 degrees C. Small temperature changes are therefore decisive for the quality of precipitation| i.e. whether the precipitation enters the catchments as snow or rain| which accordingly has large consequences for the residence time of water and its pathways through the catchment. Another important effect of higher winter-temperatures at Birkenes| is that stronger and more frequent seasalt episodes seem to occur. This may enhance the negative effects to aquatic organisms| because the most extreme concentrations of acute toxic Al-forms in streamwater are related to seasalt episodes during warm winters| when the precipitation comes as rain and thus leaves the catchment relatively fast through the uppermost soil layers. When seasalt-enriched water enters into the uppermost soil horizons| a large amount of sodium will be temporarily retained due to cation exchange processes| where sodium may substitute for H+ and cationic Al. At Birkenes| but also in similar acidified areas with high seasalt input| seasalt episodes are probably of greater importance for the periodic variations in streamwater H+ and Al-n+ than commonly recognized. Higher winter-temperatures may also change the timing of the highest streamwater fluxes of nitrate. This may have local consequences for the primary-production in the fjords| both quantitatively and qualitatively. Thus| global warming may have negative consequences for the surface water chemistry in near-coastal areas that also receive high amounts of acidifying atmospheric compounds| and may change the eutrophication status of many fjords. 4447,1995,4,4,EFFECTS OF ELECTRON AND ION REACTIONS ON ATMOSPHERIC LIFETIMES OF FULLY FLUORINATED COMPOUNDS,Atmospheric lifetimes are evaluated for the fully fluorinated compounds CF4| C2F6| c-C4F8| C6F14| and SF6 using a two-dimensional transport and chemistry model which includes removal by electrons and ions in the mesosphere and lower thermosphere. Laboratory measurements of the pertinent reaction rates were carried out at thermal energy for free electrons and for the atmospheric ions O+| O-2(+) O-2(-)| O-2(-)| NO+| H3O+| NO3-| and CO3-. Atmospheric removal by electrons reduces the lifetimes of c-C4F8 and SF6 from about 3200 years to 1400 and 800 years| respectively| only if the respective product anions C4F8- and SF6- do not subsequently regenerate the parent neutral compounds. Atmospheric removal by ion reactions is minor or negligible| with the largest effect (similar to 5%) being removal of C6F14 by O-2(+). Removal of CF4 and C2F6 by O+ is probably the most important single destruction process in the atmosphere for these two compounds| but their lifetimes are governed by removal at the Earth's surface in high-temperature combustors. While we show that the lifetimes of c-C4F8 and SF6 may be significantly shorter than previously estimated| these compounds remain extremely long-lived with significant global warming potentials. 4465,1995,2,4,EFFECTS OF GLOBAL WARMING ON ENERGY USE FOR SPACE HEATING AND COOLING IN THE UNITED-STATES,This study uses a three-step approach to estimate the impact of global warming on U.S. energy expenditures for space heating and cooling in residential and commercial buildings. First| average results from six different global circulation models are used to estimate the change in heating and cooling degree days in five U.S. climate zones associated with a 1 degrees centigrade (C) global warming. Second| the change in degree days is mapped into a corresponding change in U.S. energy use for space conditioning| taking account of differences in population and baseline space conditioning intensity levels across regions| under the assumption that desired indoor temperature is unaffected by climate change. Finally| we estimate the associated change in energy expenditures. We find that a global warming of 1 degrees C would reduce projected U.S. energy expenditures in 2010 by $5.5 billion (1991 dollars). This contrasts with earlier studies which have suggested modest global warming would increase U.S. expenditures on space conditioning energy. 2578,1995,2,4,EFFECTS OF INCREASED SOLAR ULTRAVIOLET-RADIATION ON AQUATIC ECOSYSTEMS,Aquatic systems supply humans with vast amounts of food| primarily in the form of finfish| shellfish and seaweed. More than 30% of the world's animal protein for human consumption comes from the sea| and in many countries| particularly the developing countries| this percentage is significantly higher. As a result| it is important to know how increased levels of exposure to solar UV-B radiation (280-315 nm) might affect the productivity of aquatic systems. In addition| the oceans play a key role with respect to global warming. Marine phytoplankton are a major sink for atmospheric carbon-dioxide| and they have a decisive role in the development of future trends of carbon dioxide concentrations in the atmosphere. The relative importance of the net uptake of carbon dioxide by the biological pump in the ocean and by the terrestrial biosphere is a topic of much current research. Phytoplankton form the foundation on which the very survival of aquatic food webs depends. Marine phytoplankton are not uniformly distributed throughout the oceans of the world. The highest concentrations are found at high latitudes while| with the exception of upwelling areas on the continental shelves| the tropics and subtropics have 10 to 100 times lower concentrations. In addition to nutrients| temperature| salinity and light availability| the high levels of exposure to solar UV-B radiation that normally occur within the tropics and subtropics may play a role in phytoplankton distributions. A major loss in primary biomass productivity may have significant consequences for the intricate food web in aquatic ecosystems and affect food productivity. It has been estimated that a 16% ozone depletion could result in a 5% loss in phytoplankton| which equals a loss of about 7 million tons of fish per year. Biological effects of small changes in UV-B exposure may be difficult to determine because the biological uncertainties and variations are large| and the baseline productivity for pre-ozone-loss eras is not well established. Phytoplankton productivity is limited to the euphotic zone| the upper layer of the water column in which there is sufficient sunlight to support net productivity. The position of the organisms in the euphotic zone is influenced by the action of wind and waves. In addition| many phytoplankton are capable of active movements that enhance their productivity and| therefore| their survival. Like humans| phytoplankton cannot perceive| and thereby avoid| UV-B radiation. Exposure to solar UV-B radiation has been shown to affect both orientation mechanisms and motility in phytoplankton| resulting in reduced survival rates for these organisms. Researchers have directly measured the increase in| and penetration of| UV-B radiation in Antarctic waters| and have provided conclusive evidence of direct ozone-related effects within natural phytoplankton communities. Making use of the space and time variability of the UV-B front associated with the Antarctic ozone hole| researchers assessed phytoplankton productivity within the hole compared to that outside the hole. The results show a direct reduction in phytoplankton production due to ozone-related increases in UV-B. One study has indicated a 6-12% reduction in the marginal ice zone. In recent years| there has been increased interest in UV-B effects on macroalgae and seagrasses. In contrast to the phytoplankton| most macrophytes are attached to their growing site| thereby restricting them to specific growth areas and the resultant exposure to UV-B radiation. Recent studies have demonstrated that photosynthesis is inhibited in many red| brown| and green benthic algae. Solar UV-B radiation has been found to cause damage to early developmental stages of fish| shrimp| crab| amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development. Even at current levels| solar UV-B radiation is a limiting factor| and small increases in UV-B exposure could result in significant reduction in the size of the population of consumer organisms. At high latitudes (over 40 degrees N) the late-spring increases in UV-B exposure may affect some species because the UV-B enhancement occurs at critical phases of their development. Even small increases or temporary fluctuations in UV-B may affect relatively sensitive species. Recent studies have addressed the potential impact of chlorofluorocarbon substitutes and their degradation products. Some hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs)| notably HFC134a| HCFC123| and HCFC124| are degraded| generating trifluoroacetic acid (TFA) as their main product. TFA is mildly toxic to most marine and freshwater phytoplankton. It is still speculative if TFA is concentrated in the food web. Even if produced well into the next century| TFA is unlikely to reach toxic levels for oceanic phytoplankton; however| it could reach toxic levels in restricted aquatic systems. Although there is overwhelming evidence that increased UV-B exposure is harmful to aquatic ecosystems| the potential damage can only be roughly estimated at the present time. 4341,1995,3,3,EFFICIENCY| SUSTAINABILITY AND GLOBAL WARMING,Economic analyses of global warming have typically been grounded in the theory of economic efficiency. Such analyses may be inappropriate because many of the underlying concerns about climate change are rooted not in efficiency| but in the intergenerational allocation of economic endowments. A simple economic model is developed which demonstrates that an efficient economy is not necessarily a sustainable economy. This result leads directly to questions about the policy relevance of several economic studies of the issue. We then consider policy alternatives to address global warming in the context of economies with the dual objectives of efficiency and sustainability| with particular attention to carbon-based taxes. 4362,1995,3,3,EFFORTS OF ELECTRIC UTILITIES IN JAPAN TO REDUCE CO2 EMISSION,This paper discusses the present status of efforts made by Japanese electric utilities| including plans to realize the optimal combination of fossil power and hydraulic power with nuclear power as the main power source| the increase of energy use efficiency| studies on CO2 recovery and fixation| and international cooperation related to these efforts. Also| as an example of efforts made by Japanese electric utilities| this paper discusses the efforts of Kansai Electric Power Company to prevent global warming. This discussion centers on attempts to make technological breakthroughs| such as studies on CO2 recovery and fixation| and international joint research project on the development of tropical forests regeneration technology. 4313,1995,4,3,Emissions of greenhouse gases from agriculture| land-use change| and forestry in the Gambia,The Gambia has successfully completed a national greenhouse gas emissions inventory based on the results of a study funded by the United Nations Environment Programme (UNEP)/Global Environment Facility (GEF) Country Case Study Program. The concepts of multisectoral| multidisciplinary| and interdisciplinary collaboration were most useful in the preparation of this inventory. New data were gathered during the study period| some through regional collaboration with institutions such as Environment and Development in the Third World (ENDA-TM) Energy Program and the Ecological Monitoring Center in Dakar| Senegal| and some through national surveys and the use of remote sensing techniques| as in the Bushfires Survey. Most of the data collected are used in this paper. The Intergovernmental Panel on Climate Change/Organisation for Economic Go-operation and Development/International Energy Agency (IPCC/OECD/IEA) methodology is used to calculate greenhouse gas emissions. Many of the default data in the IPCC/OECD/IEA methodology have also been used. Overall results indicate that in the biomass sectors (agriculture| forestry| and land-use change) carbon dioxide (CO2) is emitted most| with a total of 1.7 Tg. This is followed by methane (CH4)| 22.3 Gg; carbon monoxide (CO)| 18.7 Gg; nitrogen oxides (NOx)| 0.3 Gg; and nitrous oxide (N2O)| 0.014 Gg. The Global Warming Potential (GWP) was used as an index to describe the relative effects of the various gases reported here. Based on the emissions in The Gambia in 1993| it was found that CO2 will contribute 75%| CH4 about 24.5%| and N2O 0.2% of the warming expected in the 100-year period beginning in 1993. The results in this analysis are limited by the shortcomings of the IPCC/OECD/IEA methodology and scarce national data Because the methodology was developed outside of the developing world| most of its emissions factors and coefficients were developed and tested in environments that are very different from The Gambia. This is likely to introduce some uncertainties into the results of the calculations. Factors and coefficients that are country- or region-specific are likely to provide more accurate results and should be developed. The surveys were conducted either during the wet season or just at the end of the wet season. This seasonal factor should contribute to variations in the results| particularly in the livestock numbers and composition survey. Use of one-time survey data is also likely to introduce uncertainty into the results. 4431,1995,2,4,ENVIRONMENTAL AND SUBSTRATE CONTROLS OVER CARBON AND NITROGEN MINERALIZATION IN NORTHERN WETLANDS,Northern wetlands may be a potential carbon source to the atmosphere upon global warming| particularly with regard to methane. However| recent conclusions have largely been based on short-term field measurements. We incubated three wetland soils representing a range of substrate quality for 80 wk in the laboratory under both aerobic and anaerobic conditions at 15 degrees and 30 degrees C. The soils were obtained from a Scirpus-Carex-dominated meadow in an abandoned beaver pond and from the surface and at 1 m depth of a spruce (Picea)-Sphagnum bog in Voyageurs National Park| Minnesota. Substrate quality was assessed by fractionation of carbon compounds and summarized using principal components analysis. Nitrogen and carbon mineralization| the partitioning of carbon between carbon dioxide and methane| pH| and Eh were measured periodically over the course of the incubation. The responses of nitrogen mineralization| carbon mineralization| and trace gas partitioning to both temperature and aeration depended strongly on the substrate quality of the soils. Sedge meadow soil had the highest nitrogen and carbon mineralization rates and methane production under anaerobic conditions| and carbon mineralization under aerobic conditions| but the surface peats had the highest nitrogen mineralization rates under aerobic conditions. Methanogenesis was highest in the sedge soil but less sensitive to temperature than in the peats. A double exponential model showed that most of the variation in nitrogen and carbon mineralization among the soils and treatments was accounted for by differences in the size and kinetics of a relatively small labile pool. The kinetics of this pool were more sensitive to changes in temperature and aeration than that of the larger recalcitrant pool. Principal components analysis separated the soils on the basis of labile and recalcitrant carbon fractions. Total C and N mineralization correlated positively with the factor representing labile elements| while methanogenesis also showed a negative correlation with the factor representing recalcitrant elements. Estimates of atmospheric feedbacks from northern wetlands upon climatic change must account for extreme local variation in substrate quality and wetland type; global projections based on extrapolations from a few field measurements do not account for this local variation and may be in error. 4328,1995,3,2,ENVIRONMENTAL IMPACTS OF SEQUESTERING CARBON THROUGH FORESTATION,An issue that arises when considering the potential damages of climate change is whether it is possible to slow or stop human caused climate change. One suggestion to reduce the threat of global warming is to change our management of forests to offset carbon emissions. This study examines the impacts of such a policy on environmental amenities in existing Douglas-fir forests. In this analysis Douglas-fir forest management is modelled in a Faustmann framework| where the forest produces three goods: timber| carbon sequestration and amenities. Using this framework| the level of amenities under profit-maximizing and carbon-sequestration management regimes are compared. The change in the level of seven specific amenities is modelled. These amenities include trout| wildlife diversity| visual aesthetics| soil stability| deer populations| elk populations| and water yield. The study finds that the effect of a carbon sequestration policy will depend on the discount rate chosen. In most situations externalities vary less than plus or minus ten percent. However| those externalities that exhibit discontinuities in their relationship to forest age may vary a hundred percent or more depending on the discount rare used. 2553,1995,4,4,ESTIMATION OF SOYBEAN YIELDS AT COUNTY AND STATE LEVELS USING GLYCIM - A CASE-STUDY FOR IOWA,Global climate change could have a significant impact on important food crops such as soybean [Glycine max (L.) Merr.]. To assess the impact of these environmental changes| estimates of crop yields are needed| with special reference to regional responses in key production areas. The objective of this study was to examine the performance of the GLYCIM soybean crop model in modeling regional soybean yields in Iowa at the state and county level| over a 20-yr period. The GLYCIM model has been extended to run for multiple years and combined with aggregations of soil and weather data to provide simulation over large areas| Soils data were aggregated to the soil association level in 18 sample counties so as to provide two-county data sets in each Crop Reporting District (CRD). Weather files for each CRD spanning the period 1972 to 1991 were used to provide current climate information. Simulation runs were made for each year and county. Statewide yields were estimated as an average of county yields. Statistical measures of simulation success indicated that| using aggregated characteristics| the model was best able to simulate the 20-yr mean yield at the state and county level| as well as long-term yield variability. Poorer results of modeling yields in particular years were obtained. This validation establishes the model's ability to simulate long-term yield averages under current conditions| and lays the groundwork for future simulations using altered climate scenarios. 2582,1995,2,4,EVALUATING GROWTH OF THE PORCUPINE CARIBOU HERD USING A STOCHASTIC-MODEL,Estimates of the relative effects of demographic parameters on population rates of change| and of the level of natural variation in these parameters| are necessary to address potential effects of perturbations on populations. We used a stochastic model| based on survival and reproduction estimates of the Porcupine Caribou (Rangifer tarandus granti) Herd (PCH)| during 1983-89 and 1989-92 to obtain distributions of potential population rates of change (r). The distribution of r produced by 1|000 trajectories of our simulation model (1983-89| rBAR = 0.013; 1989-92| rBAR = 0.003) encompassed the rate of increase calculated from an independent series of photo-survey data over the same years (1983-89| r = 0.048; 1989-92| r = -0.035). Changes in adult female survival had the largest effect on r| followed by changes in calf survival. We hypothesized that petroleum development on calving grounds| or changes in calving and post-calving habitats due to global climate change| would affect model input parameters. A decline in annual adult female survival from 0.871 to 0.847| or a decline in annual calf survival from 0.518 to 0.472| would be sufficient to cause a declining population| if all other input estimates remained the same. We then used these lower survival rates| in conjunction with our estimated amount of among-year variation| to determine a range of resulting population trajectories. Stochastic models can be used to better understand dynamics of populations| optimize sampling investment| and evaluate potential effects of various factors on population growth. 2598,1995,4,4,EVALUATING THE EFFECTS OF ELEVATED LEVELS OF ATMOSPHERIC TRACE GASES ON HERBS AND SHRUBS - A PROTOTYPE DUAL ARRAY FIELD EXPOSURE SYSTEM,In the context of global climate change| an understanding of the long-term effects of increasing concentrations of atmospheric trace gases (carbon dioxide| CO2| ozone| O-3| oxides of nitrogen| NOx etc.) on both cultivated and native vegetation is of utmost importance. Over the years| under field conditions| various trace gas-vegetation exposure methodologies with differing advantages and disadvantages have been used. Because of these variable criteria| with elevated O-3 or CO2 levels| at the present time the approach of free-air experimental-release of the gas into study plots is attracting much attention. However| in the case of CO2| this approach (using 15 m diameter study plot with a single circular array of vent pipes) has proven to be cost prohibitive (about $59000-98000/year/replicate) due to the consumption of significant quantities of the gas to perform the experiment (CO2 level elevated to 400 ppm above the ambient). Therefore| in this paper| we present a new approach consisting of a dual concentric exposure array of vertical risers or vent pipes. The purpose of the outer array (17 m diameter) is to vent ambient air outward and toward the incoming wind thus providing an air curtain to reduce the velocity of that incoming wind to simulate the mode or the most frequently occurring wind speed at the study site. The inner array (15 m diameter) vents the required elevated levels of trace gases (CO2| O-3| etc.) into the study plot. This dual array system is designed to provide spatial homogeneity (shown through diffusion modeling) of the desired trace-gas levels within the study plot and to also reduce its consumption. As an example| while in the single-array free-air CO2-release system the consumption of CO2 to elevate its ambient concentration by 400 ppm is calculated to be about 980 tons/year/replicate| it is estimated that in the dual array system it would be approximately 590 tons/year/replicate. Thus| the dual array system may provide substantial cost savings ($24000-39000/year/replicate) in the CO2 consumption ($60-100/ton of CO2) alone. Similarly| benefits in the requirements of other trace gases (O-3| NOx| etc.) are expected| in future multivariate studies on global climate change. 4428,1995,2,2,EVALUATION OF THE POTENTIAL IMPACT OF METHANE CLATHRATE DESTABILIZATION ON FUTURE GLOBAL WARMING,Future global warming due to anthropogenic emissions of greenhouse gases has the potential to destabilize methane clathrates| which are found in permafrost regions and in continental slope sediments worldwide| resulting in the release of methane gas. Since methane is a strong greenhouse gas| this could produce a potentially important positive feedback. Here| the coupled heat transfer and methane destabilization process in oceanic sediments is modeled in a series of one-dimensional| vertical columns on a 1 degrees x 1 degrees global grid. Terrestrial permafrost is divided into 11 columns based on mean annual surface air temperature. Our base case clathrate distribution results in about 24|000 Gt C as methane clathrate in marine sediments and about 800 Gt C in terrestrial sediments| only a small fraction of which could be destabilized by future global warming. Scenarios of anthropogenic CO2( )and CH4 emission are used to drive a simple model| of the carbon cycle| yielding scenarios of CO2 and CH4 concentration increase. These increases drive a one-dimensional coupled atmosphere-ocean climate model. Globally averaged temperature changes as a function of time and ocean depth are used as upper boundary conditions to drive the heat transfer/methane clathrate release models. Three versions of the ocean model are used which result in different temperature perturbations at the sediment-water interface: a purely diffusive ocean model| an upwelling-diffusion ocean model with fixed temperature of bottom water formation| and an upwelling-diffusion ocean model with a feedback between surface temperature and the upwelling velocity. Methane release from clathrate destabilization is added to the anthropogenic CH4 emission| leading to stronger increases in both CH4 and CO2 concentration. Based on a wide variety of parameter input assumptions and anthropogenic emission scenarios| it appears that the potential impact on global warming of methane clathrate destabilization is smaller than the difference in warming between low and medium| or medium and high anthropogenic CO2 emission scenarios| or arising from a factor of two variation in climate sensitivity. Global warming increases by 10-25% compared to the case without clathrate destabilization for our scenarios using what| in many respects| are worst case assumptions. 4380,1995,2,4,FIRE| GLOBAL WARMING| AND THE CARBON BALANCE OF BOREAL FORESTS,Fire strongly influences carbon cycling and storage in boreal forests. In the near-term| if global warming occurs| the frequency and intensity of fires in boreal forests are likely to increase significantly. A sensitivity analysis on the relationship between fire and carbon storage in the living-biomass and ground-layer compartments of boreal forests was performed to determine how the carbon stocks would be expected to change as a result of global warming. A model was developed to study this sensitivity. The model shows if the annual area burned in boreal forests increases by 50%| as predicted by some studies| then the amount of carbon stored in the ground layer would decrease between 3.5 and 5.6 kg/m(2)| and the amount of carbon stored in the living biomass would increase by 1.2 kg/m(2). There would be a net loss of carbon in boreal forests between 2.3 and 4.4 kg/m(2)| or 27.1-51.9 Pg on a global scale. Because the carbon in the ground layer is lost more quickly than carbon is accumulated in living biomass| this could lead to a short-term release of carbon over the next 50-100 yr at a rate of 0.33-0.8 Pg/yr| dependent on the distribution of carbon between organic and mineral soil in the ground layer (which is presently not well-understood) and the increase in fire frequency caused by global warming. 4371,1995,2,3,FOSSIL-FUELS AND RESPONSES TO GLOBAL WARMING,The main point of this paper is that we| with or without climate change as a driving force| should expect to see major surprises both in energy and energy technologies in the decades to year 2050. If antropogenic climate change emerge as a major and global driving force| the likelihood for CO2-sequestration.(for electricity and hydrogen production) to take a share of the energy market is quite high. Catastrophic scenarios based on the whole fossil fuel reserve being burned and emitted to the atmosphere is not realistic. 4395,1995,2,4,GENOME SIZE PREDICTS FROST-RESISTANCE IN BRITISH HERBACEOUS PLANTS - IMPLICATIONS FOR RATES OF VEGETATION RESPONSE TO GLOBAL WARMING,1. Simulated late frost was applied to five herbaceous plant communities in Derbyshire| UK. The results establish a clear positive relationship between the frost resistance of the above-ground biomass and independently published estimates of genome size. 2. Previous studies have established that in small genome species the dependence of growth upon current cell divisions dictates that development is delayed until warmer summer conditions. As a result of this| we suggest that selection pressures promoting frost tolerance will have been less pronounced in these species and that in temperate climates their potential responsiveness to global warming could be curtailed by the continued occurrence of late-frost events. 2546,1995,5,4,GEOCHRONOLOGY OF DROWNED HAWAIIAN CORAL-REEFS,Two deeply submerged coral reefs were sampled with the HURL submersible Pisces V off the islands of Hawaii and Maul. An ancient fringing reef at 950 m depth on the Kohala dope of Hawaii was observed from deep-towed camera photographs and during submersible operations. A second reef at 1650 m depth on the Haleakala slope of Maul was observed on side-scan images| deep-towed camera photographs and during submersible observations. Ages of the two reefs were determined by electron spin resonance dating with a signal intensity for aragonitic coral at g = 2.0007 used to ascertain the accumulated dose by the additive dose method. Uranium concentration was measured by neutron activation analysis. The chronology of the reefs indicates that drowning coincided with periods of rapid global climate change at the termination of continental glaciation at approximately 250 ka and 340 ka. The drowning events correlate with oxygen isotope stage boundaries 7/8 and 9/10. These data support models of reef drowning on subsiding volcanic edifices. 4458,1995,4,5,GLACIERS AND GLOBAL WARMING,Ice core and mass balance studies from glaciers| ice caps and ice sheets constitute an ideal medium for monitoring and studying present and past environmental change and| as such| make a valuable contribution to the present debate over anthropogenic forcing of climate. Data derived from 32 years of measurements in the Canadian Arctic show no significant trends in glacier mass balance| ice melt| or snow accumulation| although the mass balance continues to be slightly negative. Models suggest that industrial aerosol loading of the atmosphere should add to the warming effect of greenhouse gases. However| we have found a sharp increase in the concentration of industrial pollutants in snow deposited since the early 1950's which makes the trendless nature of our various time series surprising. Spatial differences in the nature of climatic change may account for the lack of trend in the Queen Elizabeth Islands but encourages similar investigations to this study elsewhere in the circumpolar region. A global warming trend over the past 150 years has been demonstrated from instrumental data and is evident in our ice cores. However| the ice core data and glacier geometry changes in the Canadian Arctic suggest the Arctic warming is more pronounced in summer than winter. The same warming trend is not unique when viewed in the context of changes over the past 10|000 or 100|000 years. This suggests the 150-year trend is part of the natural climate variability.
2548,1995,3,3,GLOBAL CLIMATE RESEARCH - INFORMING THE DECISION-PROCESS,Public awareness of the potential for global climate change resulting from human activities has grown substantially in recent years. Policy actions aimed at greenhouse gas emissions include international accords such as the U.N. Framework Convention on Climate Change| national goals such as those set out in the U.S. Climate Change Action Plan| and state-level consideration of carbon dioxide emissions in integrated resource planning. Over half of human greenhouse gas emissions are believed to be CO2. Thus the energy sector plays an important role in strategies to address the potential for climate change. Policy actions taken to mitigate the potential for climate change could affect electric utilities in many ways| as could actual changes in climate. EPRI conducts a wide-ranging research program that includes estimating the macroeconomic costs of compliance with emissions reduction proposals determining the potential impacts of climate change| and developing integrated assessments to explore the advantages of various policy alternatives. EPRI has initiated a comprehensive effort to provide individual member utilities with the analytical tools they need to develop their own strategies for meeting emissions reduction goals. 2600,1995,2,4,GLOBAL CLIMATE-CHANGE - MODELING THE POTENTIAL RESPONSES OF AGROECOSYSTEMS WITH SPECIAL REFERENCE TO CROP PROTECTION,Pests and diseases reduce yields to lower levels than those that could have been potentially obtained| given the restrictions of climate| nutrients and crop varieties. Climatic change not only affects the potential yield levels| but it may also modify the effects of pests and diseases. Modelling can serve as a tool to integrate these processes| ranging from simple removal of plant material to subtle toxic and hormonal effects. Modelling can help to quantify different modes of action such as on photosynthesis| root activity| assimilate partitioning| morphology| and their interactions. As to climatic change| little is known about pests| diseases and weeds. If climatic change causes a gradual shift of agricultural regions| crops and their associated pests| diseases and weeds will migrate together| though at different rates maybe. To a limited extent| new outbreaks can be foreseen given the changed environmental conditions. Methodology is available| and some interesting results are on record. Specific changes such as an increase in the CO2 content in the air and in UV radiation ave not likely to have large effects. Increasing atmospheric CO2 reduces crop nitrogen content| which may retard many pests and diseases| and change the composition of the weed flora which accompanies crops. Some cautionary remarks are made to avoid jumping to conclusions. 4385,1995,3,3,GLOBAL CO2 EMISSIONS TRADING - EARLY LESSONS FROM THE US ACID-RAIN PROGRAM,The U.S. Environmental Protection Agency is implementing a program of SO2 emission allowance trading as part of the Acid Rain Program authorized by the Clean Air Act Amendments of 1990. Electric utilities may use allowance trading as part of their compliance strategy to meet SO2 emission reduction requirements| which begin in 1995. In the interest of a free market in emission credits| some utilities began trading in 1992. A strict but essential requirement for continuous-emissions monitoring was developed to support the trading program. This program is being widely watched and will be evaluated as part of an effort to determine if market concepts can be successfully extended to other environmental issues. One such issue is greenhouse gas emissions and their link with global warming and climate change. This paper focuses on the early lessons learned| issues| and challenges involved in going from a domestic electric utility SO2 emissions trading program to inter-industry| inter-gas and international as well as national emissions trading and offsets programs. Prominent among these issues are CO2 allowance allocations| equity| emissions monitoring| enforcement| and cost-effectiveness. 2540,1995,2,4,Global forest systems: An uncertain response to atmospheric pollutants and global climate change?,Forest systems cover more than 4.1 x 10(9) ha of the Earth's land area. The future response and feedbacks of forest systems to atmospheric pollutants and projected climate change may be significant. Boreal| temperate and tropical forest systems play a prominent role in carbon (C)| nitrogen (N) and sulfur (S) biogeochemical cycles at regional and global scales. The timing and magnitude of future changes in forest systems will depend on environmental factors such as a changing global climate| an accumulation of CO2 in the atmosphere| and increase global mineralization of nutrients such as N and S. The interactive effects of all these factors on the world's forest regions are complex and not intuitively obvious and are likely to differ among geographic regions. Although the potential effects of some atmospheric pollutants on forest systems have been observed or simulated| large uncertainty exists in our ability to project future forest distribution| composition and productivity under transient or nontransient global climate change scenarios. The potential to manage and adapt forests to future global environmental conditions varies widely among nations. Mitigation practices| such as liming or fertilization to ameliorate excess NOx or SOx or forest management to sequester CO2 are now being applied in selected nations worldwide. 4375,1995,2,4,GLOBAL MEAN SEA-LEVEL VARIATIONS FROM TOPEX/POSEIDON ALTIMETER DATA,The TOPEX/POSEIDON satellite altimeter mission has measured global mean sea level every 10 days over the last 2 years with a precision of 4 millimeters| which approaches the requirements for climate change research. The estimated rate of sea level change is +3.9 +/- 0.8 millimeters per year. A substantial portion of this trend may represent a short-term variation unrelated to the long-term signal expected from global warming. For this reason| and because the long-term measurement accuracy requires additional monitoring| a longer time series is necessary before climate change signals can be unequivocally detected. 4430,1995,2,4,GLOBAL WARMING AND SOIL MICROCLIMATE - RESULTS FROM A MEADOW-WARMING EXPERIMENT,We used overhead infrared radiators to add a constant increment of approximate to 15 W/m(2)| over 2 yr| to the downward heat flux on five 30-m(2) montane meadow plots in Gunnison County| Colorado| USA. Heating advanced snowmelt by approximate to 1 wk| increased summer soil temperatures by up to 3 degrees C| and reduced summer soil moisture levels by up to 25% compared to control plots. Soil microclimate response to heating varied with season| time of day| weather conditions| and location along the microclimate and vegetation gradient within each plot| with the largest temperature increase observed in daytime and in the drier| more sparsely vegetated zone of each plot. Day-to-day variation in the daily-averaged temperature response to heating in the drier zone was negatively correlated with that in the wetter zone. Our experimental manipulation provides a novel and effective method for investigating feedback processes linking climate| soil| and vegetation. 4432,1995,4,3,GLOBAL WARMING POTENTIALS - THE CASE OF EMISSIONS FROM DAMS,The global warming potential index (GWP) has been proposed to quantitatively compare the integrated greenhouse effect of different gases. However| the use of the GWP index is still subject to major conceptual difficulties. Here we revise and generalize this index and then apply our alternative index to the case of emissions from some hydroelectric reservoirs in Brazil. Our results suggest that| though the cumulative heating effects of emissions from hydroelectric reservoirs may be far from negligible| for the cases studied hydroelectricity in general contributes less to the greenhouse effect over a long time horizon than fossil fuelled electricity generation. 4450,1995,3,3,Global warming response options in Brazil's forest sector: Comparison of project-level costs and benefits,A project-level assessment of monetary and carbon costs and benefits for five classes of global warming response options in the forest sector is attempted for typical Brazilian conditions. Options considered are: silvicultural plantations (for pulp| charcoal and sawlogs)| sustainable timber management and reduction of deforestation. Comparison of pulpwood and sawlog plantations with the vegetation characteristic of deforested areas indicates a modest carbon benefit. Plantations for charcoal can produce a substantial carbon benefit through fossil fuel substitution| but much of this calculated benefit disappears if discount rates greater than zero are applied to carbon. Sustainable timber management| when compared with existing forest| represents a net carbon loss| accumulation of carbon in wood products being insufficient to compensate for biomass reduction over a 100 year time scale. Reduction of deforestation has great potential as a global warming response option| its per-hectare carbon benefits being approximately four times that of silvicultural plantation establishment for pulp and sawlogs over a 100 year period. The costs of reducing deforestation are difficult to assess| however| due to the importance of government policy changes such as removal of land speculation and land tenure establishment as motives for clearing. Although these changes would not cost money and would have tremendous carbon and other benefits| they have not yet occurred. 4454,1995,2,4,GLOBAL-SCALE FOREST FUNCTION AND DISTRIBUTION,A model is described for predicting the dynamic changes in the proportion of tree| shrub and grass life forms at the global scale. This model is driven by the impacts of climate| soils and CO2 on global vegetation leaf area index and net primary productivity. The life-form model has been used to explore the influences of global warming and continued CO2 increase on tree cover. This reflects a realization from other modelling work that forested vegetation| at the global scale| exerts significant influences on climate| and so it is important to assess the potential for this feedback under climatic change. An increase in CO2 from 350 to 560 p.p.m. is modelled to have only a small impact on tree cover| under current climate. A regionally-consistent and global increase in temperature of c.2 degrees C and a 10 per cent increase in precipitation| but with no increase in CO2| indicates a significant potential for trees to spread into current shrub tundra| over a period of 50 years This could lead to regional warming| through changes in winter albedo. The effect of the CO2 increase is most noticeable in interaction with increases in temperature (2 degrees C) and precipitation (10 per cent). In this case the life-form model projects further increases in tree cover| particularly in areas with seasonally low periods of precipitation. 4424,1995,2,3,GLOBAL-WARMING EFFECTS ON NEW-YORK STREAMFLOWS,Impacts of global warming on streamflows were estimated for four large watersheds in New York State using a daily streamflow model. Three different 100-yr daily weather sequences were input to the model. The first was produced using statistics of current (1961-90) weather records. The second and third sequences were based on modifications of these historic statistics according to the monthly mean temperature and precipitation changes associated with a doubling of atmospheric CO2 as predicted by two different general circulation models. For 2 x CO2 conditions| mean annual water balances for all four watersheds indicated modest (1-9%) decreases in precipitation| but much larger (16-42%) decreases in streamflow due to increases in evapotranspiration. Winter flows generally increased| but flows in the remaining seasons often decreased. Monthly streamflow changes varied considerably among watersheds| and we could not attribute these changes to specific differences in land uses or soils. 4309,1995,3,4,Greenhouse gas emission inventory for Senegal| 1991,The first greenhouse gas (GHG) emission estimates for Senegal for the year 1991| were produced according to the draft IPCC/OECD guidelines for national inventories of GHGs. Despite certain discrepancies| nonavailability of data| the quality of some of the data collected| and the methodology| the estimates provide a provisional basis for Senegal to fulfill its obligations under the UN Framework Convention on Climate Change. This inventory reveals that GHG emissions in Senegal| like those in many developing countries| can mainly be attributed to the use of biomass for energy| land-use change and forestry| and savanna burning. Taking into account the direct global warming potential of the main GHGs (CO2| CH4 and N2O)| Senegal's emissions are estimated at 17.6 Tg ECO(2). The major gases emitted are CO2 (61% of GHG emissions)| followed by CH4 (35%) and N2O (4%). Energy accounts for 45% of total emissions (12% from fossil energy and 33% from traditional biomass energy); land-use change and forests| 18%; agriculture| 24%; waste| 12%; and industry| 1%. 2557,1995,2,3,GREENHOUSE HYDROLOGY,Hydrological processes are an integral component of both global climate change arising from increasing concentrations of greenhouse gases and the assessment of subsequent terrestrial impacts. This article examines the potential sensivity of water resources in the UK to climatic change as exemplified by the 1988-92 drought. The representation of hydrological processes at three distinct model scales is then discussed with reference to global hydrology| regional downscaling and catchment-scale responses. A final section speculates on future directions of research for an emerging greenhouse hydrology. 2580,1995,3,3,GREENHOUSE-GAS DECISION TOOLS,Global climate change is an environmental issue with important strategic ramifications for the electric utility industry. Although no mandatory greenhouse gas (GHG) emissions control programs now exist| many utilities have decided to participate in voluntary emissions reduction and reporting efforts under the Department of Energy's Climate Challenge program and the Energy Policy Act of 1992. Given uncertainty about possible future regulation and the potentially huge stakes of such regulation| utilities are increasingly faking GHG emissions into account in planning for the future. EPRI is developing a set of decision fools to help utilities in this effort. One of these products is a greenhouse gas accounting framework| scheduled for release this year. 4420,1995,3,3,HYDROELECTRIC DAMS IN THE BRAZILIAN AMAZON AS SOURCES OF GREENHOUSE GASES,Existing hydroelectric dams in Brazilian Amazonia emitted about 0.26 million tons of methane and 38 million tons of carbon dioxide in 1990. The methane emissions represent an essentially permanent addition to gas fluxed from the region| rather than a one-time release. The total area of reservoirs planned in the region is about 20 times the area existing in 1990| implying a potential annual methane release of about 5.2 million tons. About 40% of this estimated release is form underwater decay of forest biomass| which is the most uncertain of the components in the calculation. Methane is also released in significant quantities from open water| macrophyte beds| and above-water decay of forest biomass. Hydroelectric dams release a large pulse of carbon dioxide from above-water decay of trees left standing in the reservoirs| especially during the first decade after closing. This elevates the expected global warming impact of-the dams to levels much higher than would occur by generating the same power from fossil fuels. In 1990| the impoundment behind the Balbina Dam (closed in 1987) had over 20 times more impact on expectable global warming than would generating the same power from fossil fuels| white the Tucurui Dam (closed in 1984) had 0.4 times the impact of fossil fuels. Because of the large area flooded per unit of electricity generated at Balbina| 'greenhouse' gas emissions are expected to exceed avoided fossil-fuel emissions indefinitely. 2547,1995,5,3,Identification of cultivated Pandanus and Colocasia in pollen records and the implications for the study of early agriculture in New Guinea,Pollen records from the island of New Guinea| spanning the last 60 000 years| show a vegetation system sensitive to global climate change and strongly influenced by anthropogenic activity. The evidence for anthropogenic activity in pollen diagrams has focused on indirect indicators such as forest clearance| burning and increases in arable weeds. Tracing individual cultivars has proven to be very difficult as the major cultivated plants| in this case dominated by root crops| have low pollen production| are insect-pollinated or are harvested before flowering occurs. The identification of some cultivars is further restricted by limited information on pollen morphology. The pollen morphology of selected species from two genera (Pandanus and Colocasia)| known to include important cultivated species| have been studied Five pollen taxa are recognised after examination by light microscopy and scanning electron microscopy. It is shown that these can be easily distinguished on the broad criteria of pollen class| grain size and size of echini. The taxonomic and dispersal characteristics of the pollen morphology of these taxa are discussed and the implications of improved identification of cultivated species in late Quaternary pollen records are considered. 4449,1995,2,2,IMPACT OF EXPECTED CLIMATE-CHANGE ON MANGROVES,There is a consensus of scientific opinion that the activities of man will cause a significant change in the global climate over the next hundred years. The rising level of carbon dioxide and other industrial gases in the atmosphere may lead to global warming with an accompanying rise in sea-level. Mangrove ecosystems grow in the intertidal zones in tropical and sub-tropical regions and are likely to be early indicators of the effects of climate change. The best estimates of predicted climate change in the literature are presented. It is suggested that a rise in mean sea-level may be the most important factor influencing the future distribution of mangroves but that the effect will vary dramatically depending on the local rate of sea-level rise and the availability of sediment to support reestablishment of the mangroves. The predicted rise in mean air temperature will probably be of little consequence to the development of mangroves in general but it may mean that the presence of mangroves will move further north and south| though this will depend on a number of additional factors. The effect of enhanced atmospheric CO2 on the growth of mangroves is unknown at this time but that there is some evidence that not all species of mangroves will respond similarly. The socio-economic impacts of the effects of climate change on mangrove ecosystems may include increased risk of flooding| increased erosion of coast lines| saline intrusion and increased storm surges. 2554,1995,2,4,IMPACT OF GLOBAL CLIMATE-CHANGE ON TEMPERATURE AND PRECIPITATION IN GREECE,A stochastic space-time model is used at four locations in Greece for estimating the effect of global climate change on daily temperature and precipitation. The approach is based on a semi-empirical downscaling of simulated daily atmospheric Circulation Patterns (CP) of General Circulation Models (GCM). Historical data and a 10-year outputs of the Max Planck Institute GCM for the 1 x CO2 and 2 x CO2 cases are used. Nine CP types for the winter and summer half years are obtained to characteriz;e large-scale climatic forcing in Greece. Local temperature and precipitation appear to be highly dependent on CP types. The space-time response of daily temperature to global climate change is slightly variable in Greece. In general| a warmer climate will imply nearly 3 degrees C increase in fall and in winter. The variability within the month will not change considerably. A slight but statistically significant increase of precipitation is obtained at one location and an insignificant increase is found at the other three locations. 4474,1995,2,4,IMPACT OF TROPICAL CYCLONES ON THE OZONE-LAYER,The question is considered about impact of tropical cyclones (TC)| one of the most intensive atmospheric phenomena| on the ozone layer. By generalizing the data obtained for last years three mechanisms of the impact are analyzed and their possible effects are evaluated. It is shown that observed positive and negative anomalies in total ozone content (TOC) in TC zone are due to dynamical and electrochemical mechanisms. The estimates of their spatial and temporal scales are obtained. Specific features of TOC variations at the stage of developing depression can be considered as an indication of its transformation in a storm while periodic oscillations of TOC under the action of gravity waves generated by TC - as an indicator of dynamics of TC. In relation to the global warming effect it is noted that one should expect increasing in the number and magnitude of negative anomalies of TOC caused by TC. This can be treated as a hazard factor at a background of minimum values of TOC in region of action of TC. 4294,1995,2,4,Impacts of environmental scenarios on chlorophyll-alpha in the management of shallow| eutrophic lakes following biomanipulation: An application of a numerical model,Accurate prediction of species changes in lake ecosystems following biomanipulation measures is of paramount importance in view of water quality management. The temporal variation of phytoplankton biomass as chlorophyll-a and transparency as Secchi depth measurements are studied in the Lake Bleiswijkse Zoom| The Netherlands| with a comprehensive structural dynamic model. In the formulation of the biological model| phytoplankton as several species| zooplankton| detritus| planktivores and benthivores| and piscivores are considered to be major contributing state variables for the model. The primary goal of this paper is to describe the possible impacts of several environmental scenarios on chlorophyll-a biomass qualitatively as it would help lake and environmental managers and relevant authorities elucidate the processes of eutrophication and biomanipulation in a broad way. Some of the scenarios that have been studied by this model are: (1) The effect of fixed stoichiometry in terms of internal nitrogen and phosphorus that are tied up within algal cells; (2) the effects of external phosphorus limitation; (3) light limitation and external nitrogen limitation on algal growth; (4) probable consequences that have taken place within the chlorophyll-a biomass due to change in biomasses of various aquatic organisms; and (5) possible changes of chlorophyll-a biomass due to higher temperatures caused by global warming. 4298,1995,2,4,IMPACTS OF SEA-LEVEL RISE ON DELTAS IN THE GULF-OF-MEXICO AND THE MEDITERRANEAN - THE IMPORTANCE OF PULSING EVENTS TO SUSTAINABILITY,In deltas| subsidence leads to a relative sea-level rise (RSLR) that is often much greater than eustatic rise alone. Because of high RSLR| deltaic wetlands will be affected early by an acceleration of eustatic sea-level rise. If there is sufficient vertical accretion| wetlands can continue to exist with RSLR; however| lack of sediment input eventually leads to excessive water logging and plant death. Areas with low tidal range| such as the Mediterranean and Gulf of Mexico| are especially vulnerable to rising water levels because the elevational growth rang of coastal vegetation is related to tide range. Reduction of suspended sediments in rivers and prevention of wetland flooding by river dikes and impoundments have reduced sediment input to Mediterranean and Gulf of Mexico deltaic wetlands. This sediment deficit will become more important with an acceleration in sea-level rise from global warming. Most sediment input occurs during strong pulsing events such as river floods and storms| and management policies and decisions are especially designed to protect against such events. Management approaches must be reoriented to take advantage of pulsing events to nourish marsh surfaces with sediments. We hypothesize that deltas can be managed to withstand significant rates of sea-level rise by taking advantage of pulsing events leading to high sediment input| and that this type of management approach will enhance ecosystem functioning. 4422,1995,3,4,Increasing the soil temperature to study global warming effects on the soil nitrogen cycle in agroecosystems,According to the GCMs air temperature will increase 3-5 degrees C above ambient in Central Europe. As one consequence the element turnover in terrestrial ecosystems should change; in particular| the large soil carbon and nitrogen pools are crucial because of their potential to further 'pollute' the globe with liquid and gaseous compounds. According to the goals of the International Geosphere-Biosphere Programme (IGBP) an ecosystem manipulation was carried out to increase the temperature of the top soil in an agroecosystem 3 degrees C above ambient and to study the effects on the nitrogen cycle. The experimental design| called HOTWORM| could be proved during a 3-month winter period to keep a constant temperature difference of 3 degrees C above ambient including freezing-thawing cycles. No changes in the soluble nitrogen pools could be measured at the end of the investigation| probably because of the shea heating period and the high spatial variability. However| N2O-N emissions were much higher in the unheated plot (0.233 kg ha(-1)) compared with the heated one (0.058 kg ha(-1)). This effect could be caused by more frequent freezing-thawing cycles in the unheated plots| which showed the highest emission rates. The importance of the reduced water content in the heated plot could not be evaluated in this investigation. Based on the experiences of this study a schedule for intensified field experiments was developed. 2577,1995,2,4,INERTIA IN PLANT COMMUNITY STRUCTURE - STATE CHANGES AFTER CESSATION OF NUTRIENT-ENRICHMENT STRESS,Water| nitrogen| and water-plus-nitrogen at levels beyond the range normally experienced by shortgrass steppe communities were applied from 1971 through 1975| plant populations were sampled through 1977| and the results of the experiment were published. Upon revisiting the plots in 1982| we found it apparent that large changes had occurred since 1977. Sampling was re-established in 1982 to follow trajectories of recovery. Our purposes in this paper are to examine how conclusions from this study changed through time| and discuss implications of these changes for monitoring potentially stressed ecosystems. Although productivities increased| dissimilarities in plant species composition at the end of the 5 yr of nutrient treatments were not significantly different from controls. Two years after cessation of the treatments exotic ''weed'' species were increasing in water-plus-nitrogen treated communities| and community dissimilarities were diverging in water and water-plus-nitrogen treated communities. Seven years after cessation of treatments all communities were significantly different from controls. Exotics were more than ten times more abundant in water-plus-nitrogen and nitrogen treated communities than they had been 2 yr post-treatment. A consistent trend in recovery of all treated communities was evident over the next 5 yr. However| the trend towards recovery reversed over the next four consecutive years in the previously water-plus-nitrogen and water treated communities. The four-to-five year cycles in species composition and abundance of exotics towards| and then away from| conditions in undisturbed control communities were not related to weather but large accumulations of litter suggested biotic regulation. Inertia of existing plant populations| or the tendency to continue to occupy a site when conditions become unfavorable| can mask both future deterioration in ecosystem condition and unstable behavior resulting from environmental stressors. Time lags in initial response means that an ecosystem can pass a threshold leading to transitions to alternate states before it is evident in structural characteristics such as species composition. Global climate change and sulfur and nitrogen oxide pollutants also have the potential to act as enrichment-stressors with initial time lags and/or positive effects and cumulative| subsequent negative effects| rather than as disturbance forces with immediate negative impacts. Sociopolitical systems| however| often require change in biological variables or negative impacts before acting to ameliorate environmental problems. The manner in which conclusions changed at various periods in time| and the potential for time lags in responses of species populations| raises questions about which variables are most useful for detection of stress and how long studies must last to be useful. 4331,1995,4,3,INFLUENCE OF CIRRUS CLOUD RADIATIVE FORCING ON CLIMATE AND CLIMATE SENSITIVITY IN A GENERAL-CIRCULATION MODEL,Six numerical experiments have been performed with a general circulation model (GCM) to study the influence of high-level cirrus clouds and global sea surface temperature (SST) perturbations on climate and climate sensitivity. The CCM used in this investigation is the third-generation ECHAM3 model developed jointly by the Max Planck Institute for Meteorology and the University of Hamburg. It is shown that the model is able to reproduce many features of the observed cloud radiative forcing with considerable skill| such as the annual mean distribution| the response to seasonal forcing| and the response to observed SST variations in the equatorial Pacific. In addition to a reference experiment where the cirrus emissivity is computed as a function of the cloud water content| two sensitivity experiments have been performed in which the cirrus emissivity is either set to zero everywhere above 400 hPa (''transparent cirrus'') or set to 1 (''black cirrus''). These three experiments are repeated identically| except for prescribing a globally uniform SST warming of 4 K. Similar to earlier GCM studies| the changed cloud radiative heating within the troposphere has a profound impact on the model climate. Since the initial radiative forcing introduced by the changed cirrus emissivity is much smaller than the convective or dynamical response| we conclude that the tropical circulation| in particular| is maintained through a positive feedback loop involving cirrus radiative heating| deep cumulus convection| and moisture supply through the large-scale dynamics. Since this interaction has been identified in at least two other GCMs employing different cumulus parameterizations| it does not crucially depend on the respective closure assumption. Moreover| the radiative-convective-dynamical coupling in the tropics is relevant also in the global warming experiment through the increase of cloud water and hence cirrus radiative heating in the warmer atmosphere. It is shown that the spin-up of the Walker circulation in both the global warming and the increased cirrus emissivity experiments is a result of a selection process which enhances the diabatic heat source through asymmetries of the circulation itself| and the extra differential heating feeds back positively on the circulation. It is also shown that cirrus clouds have a significant influence on the global climate sensitivity of the model. In the climate change experiment with the standard model| the climate sensitivity is 20% higher than in a clear-sky reference atmosphere because the increase of cirrus emissivity in the warmer atmosphere contributes substantially to the overall positive cloud feedback. In the transparent cirrus model the cloud feedback is negative| and the global sensitivity is reduced by 20% as compared to a clear-sky reference atmosphere. 4408,1995,4,4,INFRARED BAND INTENSITIES AND GLOBAL WARMING POTENTIALS OF CF4| C2F6| C3F8| C4F10| C5F12| AND C6F14,IR band intensities have been measured for the species: CF4| C2F6| C3F8| C4F10| C5F12| and C6F14 via Fourier transform spectroscopy and compared to previous literature values if available. Relative radiative forcing calculations have been performed using these data in order to determine the global warming potential of the particular species. The relative forcing (compared to CFC11| per volume) increases with molecular weight in the above series from 0.47 to 2.1| the GWP for a time horizon of 100 yrs from 1.1 to 4.7. This corresponds to a GWP on CO2 basis per mass of about 5000. 2584,1995,4,4,INTEGRATED ASSESSMENT MODELS OF CLIMATE-CHANGE - AN INCOMPLETE OVERVIEW,Integrated assessment is a trendy phrase that has recently entered the vocabulary of folks in Washington| DC and elsewhere| The novelty of the term in policy analysis and policy making circles belies the longevity of this approach in the sciences and past attempts at their application to policy issues| This paper is an attempt at providing an overview of integrated assessment with a special focus on policy motivated integrated assessments of climate change| The first section provides an introduction to integrated assessments in general| followed by a discussion of the bounds to the climate change issue| The next section is devoted to a taxonomy of the policy motivated models| Then the integrated assessment effort at Carnegie Mellon is described briefly| A perspective on the challenges ahead in successful representation of natural and social dynamics in integrated assessments of global climate change is presented in the final section. 4291,1995,2,3,Interaction of acid rain and global changes: Effects on terrestrial and aquatic ecosystems,Both acid deposition and changes in the global atmosphere and climate affect terrestrial and aquatic ecosystems. In the atmosphere sulphate aerosols tend to increase haze| altering the global radiation balance. Increased nitrogen deposition to N-limited systems such as boreal forests results in increased growth and increased sequestration of atmospheric CO2| slowing the increase in CO2 levels in the atmosphere. Future reduction in S and N emissions may result in a trade-off - better with respect to some effects of acid deposition and greenhouse warming| but worse with respect to others. Global warming may cause the incidence and severity of drought to increase. Mineralisation of N and oxidation of organic S compounds release pulses of SO4| acid and Al to surface waters. Effects in lakes may include reduced deep water refugia for cold stenotherms| lower nutrient concentrations| and greater penetration of harmful UV radiation. Longer water renewal times cause declines in SO4 and NO3| due to increased in situ removal| but increases in base cations. The net result is increased internal alkalinity production. In areas characterised by cold winters| global warming may result in a major shift in hydrologic cycle| with snowmelt episodes occurring during the winter rather than the typical pattern of accumulation in the winter and melting in the spring. Increased storm frequency predicted for the future will cause increased frequency and severity of sea salt episodes in coastal regions. Predicting the interactions of regional and global environmental factors in the coming decades poses new challenges to scientists| managers and policy-makers. 4404,1995,3,3,INTERGENERATIONAL DISCOUNTING,A 'discount rate' for the consumption of future generations from current investments for their benefit is typically composed of two parts: 'time preference' and an allowance for the lower marginal utility of consumption due to higher average levels of consumption in the future| Time preference would be involved if one were postponing one's own consumption; it has little or nothing to do with income redistribution| which is what greenhouse abatement is about| A lower marginal utility of consumption is an anomaly in income redistribution: we rarely deliberately transfer consumption from the less to the more well-to-do| Time may serve as a kind of measure of distance; we may prefer beneficiaries who are closer in time| in geographical distance| in culture| surely in kinship| Perhaps to keep our thinking straight we should use a term like 'depreciation'| rather than 'discounting'. 2587,1995,3,4,INTERGENERATIONAL EQUITY| DISCOUNTING| AND THE ROLE OF COST-BENEFIT-ANALYSIS IN EVALUATING GLOBAL CLIMATE POLICY,When public policies with impacts far into the future are being debated| the question inevitably is raised whether cost-benefit analysis which discounts future costs and benefits is not biased against future generations and whether| if such discounting is appropriate at all| a lower rate should be used to avoid such bias| The debate on global climate change is no exception. This paper sketches and analyses the welfare foundations of cost-benefit analysis and from this perspective analyses the role of cost-benefit analysis in the climate policy debate| particularly with reference to intergenerational effects. The paper concludes that the cost-benefit criterion cannot provide a definitive basis for deciding whether we should commit to a longer-term programme to moderate climate change; the issues of intergenerational equity are not that global climate change will significantly lower the GNP of future generations| but relate to the possibility of science fiction-like changes in the planet that will produce catastrophic effects in the future; and the typical way in which the cost-benefit problem is posed obscures the basic choices that we should be evaluating. 4401,1995,3,4,INTERNATIONAL CO2 EMISSIONS CONTROL - AN ANALYSIS USING CETA,This paper explores issues of international cooperation in CO| emission control| We consider three cases: 'selfish|' in which region 1 controls optimally given its own damage costs and region 2 does not control; 'altruistic|) in which region 1 controls optimally given total worldwide damage costs while region 2 does not control; and 'optimal|' in which regions 1 and 2 exercise jointly optimal control of emissions and region 1 pays region 2 to participate| We find that neither region gains much in the selfish case; but both regions are better off in the optimal case than in the altruistic case| though region 1's benefits are negative in both these cases. 4367,1995,5,4,LATE PERMIAN GLOBAL COAL HIATUS LINKED TO C-13-DEPLETED CO2 FLUX INTO THE ATMOSPHERE DURING THE FINAL CONSOLIDATION OF PANGEA,At a time when all continents were finally arrayed in their Pangea supercontinental configuration (250 +/- 50 Ma)| Earth's stratigraphy records a global and very abrupt coal discontinuity| From the Tartarian stage of the Late Permian to the Middle Triassic| reduced coal productivity and/or preservation overlaps with a period of anomalous oceanic and atmospheric decrease in C-13| as recorded in marine carbonates and organic matter| and terrestrial plant and animal fossils from the Northern and Southern hemispheres| During the same short period| the peripheral margin of the entire supercontinent Pangea| except for the southern shores of Tethys| was effectively under compressive stress| This unique tectonic state caused deformation and uplift of coal-bearing foreland basins and oxidation of Pangea's vast peat deposits| The latter resulted in a rapid| massive C-13-depleted CO2 flux into the atmosphere| which in turn may have forced global warming| 4327,1995,3,3,LCA CONSIDERATIONS OF SOLID-WASTE MANAGEMENT ALTERNATIVES FOR PAPER AND PLASTICS,Boundaries of life cycle inventories of products include the entire system associated with the manufacture| use and disposal of products. To date| the solid waste disposal aspects have been analyzed primarily in terms of the volume occupied by landfilled items| and the energy recovered by waste-to-energy facilities in the case of incinerated products. Histori- cally| these have been the items of most interest. The energy consumption by solid waste operations is routinely included| but is generally quite small as compared to the energy requirements for a product manufacturing system| and is of little interest in a product system analysis.
The reason for a lack of intensive analysis of other aspects of solid waste management is that they seemed of little consequence| or the data were so poor that no analysis was possible. For example| we would like to compare the air emissions of various incinerated products| but current data on this subject are quite poor. Results of experiments do not make clear what specific air emissions are produced by burning a plastic product as compared to a paper product| for example. Data for burning pure samples of materials do not replicate the temperatures nor the complex and highly reactive chemical environment of a mixed waste incinerator.
Recent interest in ‘greenhouse gases’ has resurrected interest in this subject. If products either decay under aerobic conditions or are burned| a major product is COZ. However| if these same products are landfilled and anaerobic digestion takes place| a portion of the carbon is released as methane| which has much greater greenhouse potential than CO2 [ l- 31.
Although there is much public attention given to the concept of waste ‘entombment’ (i.e.| very slow decomposition of landfilled waste) it is clear that even well capped and maintained landfills still produce gases and leachate. Data on what happens to products in a landfill show that the range of possibilities is quite large. What happens to any one product is quite variable and unpredictable. However| a ‘screening’ analysis is possible to see if there is justification to consider more intensive study.
This analysis will consider what happens to paper or plastic products if they are burned| landfilled or composted. Because of the large uncertainty inherent in the data| the results must be considered very approximate| but the purpose is to determine if further study is warranted.
4444,1995,2,4,LITTER DECOMPOSITION| CLIMATE AND LITTER QUALITY,Litter decomposition is controlled by three main factors: climate| litter quality and the nature and abundance of the decomposing organisms. Climate is the dominant factor in areas subjected to unfavourable weather conditions| whereas litter quality largely prevails as the regulator under favourable conditions. Litter quality remains important until the late decomposition stages through its effects on humus formation. Interest in the role of litter decomposition in the global carbon cycle has increased recently since (1) increased atmospheric carbon dioxide will probably affect the chemical quality of litter (especially nitrogen content)| and (2) global warming may enhance decomposition rates. 2564,1995,4,2,LONG-TERM CHANGES OF THE DIURNAL TEMPERATURE CYCLE - IMPLICATIONS ABOUT MECHANISMS OF GLOBAL CLIMATE-CHANGE,We use a global climate model to investigate the impact of a wide range of radiative forcing and feedback mechanisms on the diurnal cycle of surface air temperature. This allows us not only to rule out many potential explanations for observed diurnal changes| but to infer fundamental information concerning the nature and location of the principal global climate forcings of this century. We conclude that the observed changes of the diurnal cycle result neither from natural climate variability nor a globally-distributed forcing| but rather they require the combination of a (negative) radiative forcing located primarily over continental regions together with the known globally-distributed forcing due to anthropogenic greenhouse gases| Tropospheric aerosols can account for part of the continentally-located forcing| but alone they do not damp the diurnal cycle as observed. Only an increase of continental cloud cover| possibly a consequence of anthropogenic aerosols| can damp the diurnal cycle by an amount comparable to observations. A corollary of these results is quantitative confirmation of the widely held suspicion that anthropogenic greenhouse gas warming has been substantially counterbalanced by a forced cooling. Under the assumption that the cloud change is sulfate driven| a further implication is that the net rate of global warming is likely to increase substantially in coming years. We note that| on the long run| the daily maximum temperature will increase by an amount not much less than the increase of the mean temperature. 4311,1995,2,4,Long-term effects of water level drawdown on the vegetation of drained pine mires in southern Finland,1. The effect of water level drawdown after drainage of mires for forestry was studied by comparing the vegetation on undrained pine-mire sites with that of sites drained 3-55 years earlier. The plant communities were analysed with respect to the following environmental variables: drainage age| total nutrient contents of surface pear| and tree stand characteristics. Canonical correspondence analysis was used to relate the environmental variables to data on the botanical composition of vegetation. 2. Two main gradients were found in the data. The first ordination axis clearly relates to a gradient in forest vegetation succession and the second axis to a gradient in peat nutrient level and pH. 3. The secondary succession towards forest vegetation started soon after drainage and proceeded most rapidly in the most nutrient-rich site types. This led to a more uniform vegetation composition between the site types. 4. Original mire species reacted differently to the changing post-drainage environment. Tall sedges (Carex lasiocarpa| C. rostrata) disappeared soon after drainage. The coverages of the mire dwarf shrubs gradually decreased with increasing tree stand volumes; Betula nana appears to have been the most sensitive species. The coverages of the Sphagna studied appear to have decreased in response to increasing tree stand shading in the order: S. fuscum > S. recurvum complex > S. magellanicum > S. russowii. 5. The development towards forest vegetation on mires may diminish the regional (gamma-) diversity on forest-dominated landscapes| even if the species (alpha-) diversity on individual sites is little affected. 6. Long-term vegetation changes after artificial water level drawdown| emphasized in this study| can be used to mimic the effects of the predicted global climatic warming on mire vegetation. 4370,1995,2,4,LONG-TERM RESPONSE OF DISTURBANCE LANDSCAPES TO HUMAN INTERVENTION AND GLOBAL CHANGE,The structure of landscapes subject to patch-forming catastrophic disturbances| or ''disturbance landscapes''| is controlled by the characteristics of the disturbance regime| including the distribution of disturbance sizes and intervals| and the rotation time. The primary landscape structure in disturbance landscapes is the structure of the mosaic of disturbance patches| which can be described by indices such as patch size and shape. The purpose of this research was to use a geographical information system-based spatial model (DISPATCH) to simulate the effects of the initial density of patches on the rate of response to alteration of a disturbance regime| the effects of global warming and cooling| and the effects of fragmentation and restoration| on the structure of a generalized temperate-zone forested disturbance landscape over a period of 400 yr. The simulations suggest that landscapes require 1/2 to 2 rotations of a new disturbance regime to adjust to that regime regardless of the size and interval distributions. Thus alterations that shorten rotations| as would be the case if global warming increases fire sizes and decreases fire intervals| produce a more rapid response than do alterations that lengthen rotations| such as cooling and fire suppression. Landscape with long rotations may be in perpetual disequilibrium with their disturbance regimes due to a mismatch between their adjustment rate and the rate of climatic change. Landscapes with similar rotation times may have different structures| because size and interval distributions independently affect landscape structure. The response of disturbance landscapes to changing disturbance regimes is governed by both the number and size of patch births. 4308,1995,2,4,LONG-TERM TRENDS IN THE ARRIVAL DATES OF SPRING MIGRANTS,Data on the spring arrival dates of 23 species of migrants in Leicestershire over a 50-year period are presented. Chiffchaff| Sand Martin| Blackcap and Sedge Warbler showed a significant trend towards earlier arrival over the period| while Tree Pipit| Cuckoo| Whinchat| Whitethroat and Garden Warbler showed It significant trend towards later arrival. Fifteen species arrived noticeably earlier in the 1940s| a period of warm springs| while several species showed earlier arrivals in the 1980s. A number of species showed later arrival dates in the 1960s and 1970s| when April temperatures were colder than average. Several species showed significant correlations between arrival date and temperature. Arrival dates of the earliest species were much more variable than those arriving later| while species arriving in the second half of April showed a generally synchronous arrival. The results are discussed in the context of global warming.
4412,1995,4,4,LOOKING BACK 10 YEARS,This paper is an update of the science of global warming| The point of departure is 1983 with the publication of the National Research Council/National Academy of Sciences report Changing Climate (1983)| The present author was chairman of the report committee and considers this an appropriate time for an update| The advances (or retreats) in the overall science are reviewed with special emphasis on those that have critical policy implications. 4393,1995,5,4,MAMMALIAN GENERIC DIVERSITY AND TURNOVER IN THE LATE PALEOCENE AND EARLY EOCENE OF THE BIGHORN AND CRAZY MOUNTAINS BASINS| WYOMING AND MONTANA (USA),Patterns of mammalian generic turnover| richness| and faunal composition were investigated for faunas from 17 biostratigraphic zones in middle Paleocene through early Eocene deposits of the Bighorn and Clarks Fork basins of northern Wyoming and the Crazy Mountains Basin of south-central Montana. Significance of turnover was evaluated (1) by comparison of observed turnover to expected turnover (calculated from the multiple regression of turnover on zone duration and generic richness)| and (2) by comparison of observed turnover to a bootstrapped turnover distribution. Patterns of turnover and richness also were assessed in light of relative sampling quality of each faunal zone. The analysis identified four intervals of significant faunal change: the Torrejonian-Tiffanian transition| the late Tiffanian| the earliest Wasatchian| and the middle-to-late Wasatchian. The first interval was characterized by a high number of last occurrences in the latest Torrejonian| resulting in a decrease in standing generic richness in the earliest Tiffanian| but no major changes in ordinal composition. During the next interval of significant turnover| the late Tiffanian| higher-than-expected first occurrences resulted in an increase in standing richness and a change in faunal composition| most probably reflecting the immigration of taxa from outside North America. The third| and most dramatic| interval of significant generic turnover took place in the earliest Wasatchian and was distinguished by a high number of first occurrences| but relatively few last occurrences. This led to a marked increase in generic richness| a pattern similar to that for the early Wasatchian of North America as a whole. The major change in faunal composition| as in the late Tiffanian| was largely composed of immigrants from other continents. The pattern of faunal change during the early Wasatchian of the Bighorn Basin| along with evidence for global warming at the Paleocene-Eocene boundary| supports previous interpretations associating this episode in mammalian evolution with the opening of high latitude intercontinental dispersal routes. During the fourth interval of interest| the middle to late Wasatchian| the Bighorn Basin fossil record shows a drop in generic richness. This differs from the overall North American pattern| and may be| in part| an artifact of still inadequate sampling for the latest part of the stratigraphic sequence in the Bighorn Basin. 2539,1995,4,4,Measuring global mean sea level variations using TOPEX/POSEIDON altimeter data,The variations of global mean sea level are an important indicator of global climate change| and their measurement can provide important information for determining the socioeconomic impact of sea level change on coastal land use. The analysis of historical tide gauge records generally indicates that sea level has risen at a rate of about 2 mm/yr during the last 100 years; however| this estimate is somewhat uncertain due to the effects of regional crustal motion| lack of uniform temporal coverage| and the limited spatial sampling of tide gauges. The prospect of measuring variations in global mean sea level has been assessed using approximately 2.5 years of satellite altimeter data from the TOPEX/POSEIDON (T/P) mission| where synoptic mapping of the geocentric height of the ocean surface is routinely achieved with a point-to-point accuracy of better than 5 cm. The global mean sea level variations measured by T/P every 10 days have an rms of 6 mm (4 mm after detrending)| some of which is shown to be correlated with sea surface temperature variations. The rate of change of global mean sea level derived from 2.5 years of data is +5.8 mm/yr with a scatter of 0.7 mm/yr. Currently| it is impossible to accurately estimate the error in the measured rate of sea level rise| since little is known about the long-term behavior of the measurement errors at the millimeter level. In addition| there is evidence from the sea surface temperature record that the measured rate of sea level rise is associated with a relatively short-term (interannual) variation unrelated to the long-term signal expected from global warming. Nevertheless| these results suggest that T/P is achieving the necessary repeatability to measure global sea level variations caused by climate change| and a longer time series will significantly improve the sea level rise estimate by averaging measurement error and real sea level variations. A longer time series will also reduce the errors in estimates of the altimeter calibration| providing an important constraint on any long-term instrument drift. Future research will focus on establishing a realistic error budget for these measurements of global mean sea level| so that they can be put in the proper context with other observations of global climate change. 4334,1995,3,3,METHANE EMISSIONS FROM CATTLE,Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. Many factors influence methane emissions from cattle and include the following: level of feed intake| type of carbohydrate in the diet| feed processing| addition of lipids or ionophores to the diet|and alterations in the ruminal microflora. Manipulation of these factors can reduce methane emissions from cattle. Many techniques exist to quantify methane emissions from individual or groups of animals. Enclosure techniques are precise but require trained animals and may limit animal movement. Isotopic and nonisotopic tracer techniques may also be used effectively. Prediction equations based on fermentation balance or feed characteristics have been used to estimate methane production. These equations are useful| but the assumptions and conditions that must be met for each equation limit their ability to accurately predict methane production. Methane production from groups of animals can be measured by mass balance| micrometeorological| or tracer methods. These techniques can measure methane emissions from animals in either indoor or outdoor enclosures. Use of these techniques and knowledge of the factors that impact methane production can result in the development of mitigation strategies to reduce methane losses by cattle. Implementation of these strategies should result in enhanced animal productivity and decreased contributions by cattle to the atmospheric methane budget. 4349,1995,2,4,MICROBIAL LIFE IN PERMAFROST - A HISTORICAL REVIEW,This paper reviews the literature on cold-adapted micro-organisms which might exist in ice and permafrost. Properly identified| microbial markers in the cryolithozone could be used in palaeoenvironmental reconstructions| in distinguishing between epigenetic and syngenetic depositional sequences| and in the recognition of secondary thaw unconformities. Cryobiological problems include (1) whether the bacteria are dead| dormant or in the active state| and (2) what factors determine the preservation of cell structures. A possible consequence of permafrost thawing| based upon predicted global warming scenarios| is that there may be an increase in microbial activity and an increase in active layer thickness. 4350,1995,2,4,MICROEVOLUTION OF MIGRATORY BEHAVIOR ILLUSTRATED BY THE BLACKCAP SYLVIA-ATRICAPILLA - 1993 WITHERBY-LECTURE,The view on how rapidly morphological| physiological| and behavioural traits may change as a result of microevolutionary processes (i.e. genetic variation and directional selection) has changed considerably in the recent past. Observations on selection of morphological traits in Darwin's Finches on the Galapagos Islands and results of a 2-way selection experiment on migratory behaviour of Blackcaps Sylvia atricapilla have indicated that substantial changes can occur within short periods. A striking case is represented by Blackcaps breeding in continental Europe. Within the past 30 years| a subpopulation has developed a 'new' migratory direction to the WNW to novel wintering areas on the British Isles. Experimental analysis of migratory orientation behaviour has demonstrated that behavioural changes can result from microevolutionary processes. Similar microevolutionary processes are likely to occur commonly| as both recent field observations and experimental results suggest. One outcome of this| which is of particular interest| involves the effects of continued global warming. Global warning is likely to favour obligate partial and short-distance migrants at higher latitudes and to be disadvantageous to long-distance migrants| and may lead to further reduction of species diversity. 4369,1995,2,3,MIDHOLOCENE PRECEDENT FOR A FUTURE RISE IN SEA-LEVEL ALONG THE ATLANTIC COAST OF NORTH-AMERICA,Sea level oscillated between 5500 and 3500 years ago at Murrells Inlet| South Carolina (33 degrees 33'N| 79 degrees 02'W). The oscillation is well constrained by marsh foraminiferal zonations. For the same time interval| data from Nova Scotia indicate an acceleration in sea-level rise and a report from the Gull of St. Lawrence suggests an oscillation of sea level at the same time. The implications are: (1) there was a eustatic sealevel oscillation of about 2 m in the mid-Holocene on the east coast of North America that is not detectable in present geophysical models of relative sea-level change; (2) if an anthropogenically derived global warming of 4 degrees C takes place| sea level may rise as much as 2 m in 500 yr along the east coast of North America. It appears that the initial rapid rise is recorded all along the eastern seaboard of North America| but detection of the subsequent fall is dependent on existing glacio-isostatic effects (either subsidence or rebound) that are independent of eustatic sea level. 4463,1995,3,4,MINIMIZING THE ENVIRONMENTAL-IMPACT OF PROCESS PLANTS - A PROCESS SYSTEMS METHODOLOGY,A Methodology for Environmental Impact Minimization (MEIM) is presented in this paper. The methodology| which embeds Life Cycle Analysis principles within a process optimization framework| involves proper definition of a consistent boundary around the process of interest| identification of the emissions inventory| quantification of environmental impact via proper metrics (for air and water pollution| solid waste| global warming and ozone depletion) and inclusion of environmental criteria within process modelling and optimization tools. A case study| the production of VCM from ethylene| is presented to illustrate the basic features of MEIM. 4413,1995,3,4,MITIGATING GLOBAL WARMING BY SUBSTITUTING TECHNOLOGY FOR ENERGY - MITIS EFFORTS AND NEW APPROACH,In the last two decades| Japan has successfully overcome energy and environmental constraints despite a fragile energy and environmental structure| while maintaining a high rate of economic growth| Much of this success can be attributed to the substitution of an unconstrained production factor (technology) for a constrained production factor (energy) stimulated by MITI's industrial technology policy| With the recent fall of international oil prices and the succeeding 'bubble economy'| Japan again faces the prospect of energy and environmental constraints| This paper reviews Japan's path and MITT's efforts to overcome energy and environmental constraints by substituting technology for energy| It also analyzes the sources of the current fear concerning energy and environmental constraints. 4342,1995,3,2,MODEL EVALUATION OF CO2 REDUCTION TECHNOLOGIES IN THE ASIA-PACIFIC REGION,Global warming is one of the most serious issues in today's world. Various innovative technologies have been proposed for the reduction of CO| emissions and the mitigation of global warming. They include (1) the WENET project| inaugurated in 1993 by the government of Japan| in which electricity produced by photovoltaic systems in vast areas such as the Sahara Desert| or by hydropower systems| is converted to hydrogen for transport to demand sites| and (2) Steinberg's Hydrocarb process| in which fossil fuels and biomass are coprocessed to produce carbon and methanol. While Japan is resource-poor| it is located relatively close to Southeast Asia and Australia| which are large regions with abundant solar energy. This paper describes an investigation of the prospects for the adoption of these innovative technologies by Japan and surrounding resource regions in the next 30 to 40 years. An optimizing energy model is developed for the purpose| and the simulation results provide several interesting suggestions regarding Japan's future strategy for combatting global warming. 4356,1995,4,3,MODEL-CALCULATIONS OF COMPETING CLIMATIC EFFECTS OF SO2 AND CO2 IN FOSSIL-FUEL COMBUSTION,Fossil fuel combustion has two competing effects on the climate system| a warming due to the emission of CO2 and other trace gases and a cooling due to sulphate particles formed from the SO2 emission. A detailed parameterization of the relationship between fossil fuel burning and the SO2 effect on backscattering and cloud albedo is implemented in a one-dimensional radiative-convective model for assessing the climatic impact. The results show that at present the cooling induced by the combined effect of SO2 completely counteracts the CO2 greenhouse warming. The model predicts that by the year 2060 the SO2-induced cooling reduces warming due to CO2 by 66% in the IPCC scenario Ball and by 27% in the IPCC scenario D. Attempts to slow-pace the fossil fuel burning will decrease the SO2 concentration| which could further increase global warming. 4460,1995,2,3,Modelling the impact on navy beans and vining peas of temperature changes predicted from global warming,Conservative estimates of global warming suggest that average daily temperature may be raised by 0.5-1.5 degrees C by the middle of the next century. This would have an impact on agricultural and horticultural production in the U.K.| and may result in a changing distribution of crops and the introduction of crops which cannot currently be grown in the U.K. The effect of a warmer climate on navy beans (Phaseolus vulgaris) and vining peas (Pisum sativum) was studied with the aid of a heat unit model. Total thermal receipt for the current and a warmer climate over the growing season of navy beans is compared with thermal requirement (sowing to crop maturity) of the crop. The analysis suggested that parts of Southern England would become thermally suitable for navy bean production| given relatively little global warming (0.5 degrees C). For vining peas| the contraction of the harvesting period due to a warmer climate| with a resulting increase of risk of a lost crop| is examined by using an accumulated day degree time scale from the start of harvest to the time when the crop is too mature. This analysis indicated that the time available for vining pea harvesting (determined by tenderometer values) may decrease by up to 25 per cent| which would significantly increase the risks in harvesting at the optimum time in traditional production areas. It is suggested that growing vining pea crops at more northerly latitudes than currently would help to compensate for the tendency of increased warming to reduce the period for which the crop could be harvested at optimum maturity. 2541,1995,4,4,Morphological responses among crop species to full-season exposures to enhanced concentrations of atmospheric CO2 and O-3,Field studies using open-top chambers were conducted at USDA-BARC involving the growth of soybeans ('89 & '90)| wheat ('91 & '92)| and corn ('91)| under increased concentrations of atmospheric CO2 and O-3. Treatment responses were compared in all cases to plants grown in charcoal-filtered (CF) air (seasonal 7-h mean = 25 +/- 3 n mol O-3 mol(-1)) having 350 or 500 mu mol CO2 mol(-1). Elevated seasonal O-3 levels for the soybean| wheat| and corn studies averaged 72.2 +/- 4| 62.7 +/- 2| and 70.2 n mol O-3 mol(-1)| respectively. Results presented were obtained for plants grown in silt loam soil under well-watered conditions. Grain yield increases in response to elevated CO2 in the absence of O-3 stress averaged 9.0| 12.0| and 1.0% for soybean| wheat| and corn:respectively. Reductions in grain yields in response to the elevated O-3 treatments at 350 mu mol CO2 mol(-1) averaged 20.0| 29.0 and 13.0% for soybean| wheat| and corn| respectively. Reductions in grain yields in response to elevated O-3 at 500 mu mol CO2 mol(-1) averaged 20.0| 8.0| and 7.0% for soybean| wheat| and corn| respectively. Dry biomass and harvest index in wheat were significantly reduced by O-3 stress at 350 mu mol mol(-1) CO2 but not at 500 u mol mol(-1) CO2. Seed weight 1000(-1) for soybeans and wheat was significantly increased by CO2 enrichment and decreased by O-3 stress. Seed weight 1000(-1) in corn was increased by O-3 stress suggesting that O-3 affected pollination resulting in fewer kernels per ear. 4426,1995,3,3,NEW DIRECTIONS FOR FINANCING GLOBAL ENVIRONMENTAL-CHANGE,The international environmental agreements negotiated in Rio de Janeiro in 1992 provide some hope for reducing the rate of global warming and saving the world's biological diversity| But it is clear that the North will vote only limited funds to facilitate the working of the Conventions| perhaps US$2 billion over the coming three years| Against the scale of the problems this is an inadequate sum| However| there are opportunities for tapping into other sources of funds| and for using official transfers as a lever for yet other funds| Additionally| enormous scope exists for reducing global environmental problems through the adoption of more sensible economic policies| The deployment of imaginative policies to 'capture' environmental value can make a substantial difference to the global environment. 2604,1995,3,3,Nitrogen transformations in wetland rice ecosystems,In Asia| rice production has increased an average 2.7% annually - due to greater fertilizer use and crop intensification together with varietal improvement and investment in irrigation facilities. Nitrogen efficiency in tropical rice is low. N-15 recovery rarely exceeds 30-40% in wetland rice production systems. Ammonia (NH3) volatilization and denitrification are recognized as major nitrogen loss mechanisms in such systems. Information on the relative importance of the two loss processes is available for few sites in Asia. The greatest losses of N are reported to occur when the fertilizer treatment leads to a high concentration of ammoniacal N in the floodwater. Results from the studies using micrometereological technique suggest that ammonia volatilization may be the most important loss process in wetland rice ecosystems. Directly measuring denitrification in the held proved more difficult than measuring NH3 volatilization due to difficulty in distinguishing the main end product of denitrification (N-2) against a large background of atmospheric N-2. However| the directly measured (N-2 + N2O) - N-15 flux for rice in Indonesia| Thailand and the Philippines rice fields was less than 1% of the applied N. Green manure incorporation in wetland rice fields reduced N losses from mineral N source due to resulting lower floodwater pH and lower partial pressure of NH3 (pNH(3)) than that of urea applied alone. At present| the integrated use of green manure and mineral N is receiving much attention in the hope of meeting farmers' desire to reduce cost of production as well as ecological considerations such as increased methane production which contribute to global climate change. Other promising alternative practices for increasing fertilizer N efficiency include improved timing and application methods| particularly through better incorporation of basal N fertilizer without standing water| deep placement| and use of coated fertilizers. 4406,1995,3,3,NO-REGRET POTENTIALS AND TECHNICAL INNOVATION - A VIABILITY APPROACH TO INTEGRATED ASSESSMENT OF CLIMATE POLICIES,This paper aims to demonstrate the advantages of a sequential approach to decision making in climate policies| This sequential approach is necessary because of the uncertainties regarding both the avoided costs of climate change and the costs of GHG emission abatement| This assessment focuses on the minimization of learning time| the reduction of technical and institutional inertia| and the possible unexpected non-linearities in abatement curves. A stylized representation of so-called 'no-regret' short-term potentials| of long-term innovation trends and of backstop technologies is used| We show that if we do take care of the inertia constraints in the decision process| both policies (namely the no-regret and the innovation process exploitation) becomes crucial in terms of minimization of the learning time. 4355,1995,3,3,NONCONVENTIONAL ENERGY-SOURCES - A SOLUTION TO GLOBAL WARMING IN THE INDIAN CONTEXT,The main thrust of this article is on the tapping and use of nonconventional energy resources to reduce the contribution to global warming in the Indian context. This article covers the steps taken by the government of India to promote nonconventional energy sources in India. 4398,1995,4,4,NONLINEAR METHODS FOR MULTIVARIATE STATISTICAL CALIBRATION AND THEIR USE IN PALEOECOLOGY - A COMPARISON OF INVERSE (K-NEAREST NEIGHBORS| PARTIAL LEAST-SQUARES AND WEIGHTED AVERAGING PARTIAL LEAST-SQUARES) AND CLASSICAL APPROACHES,Current environmental problems| such as acid rain and global warming| have greatly increased interest in fossil species assemblages as indicators of the palaeoenvironment and thus in quantitative methods for reconstructing environmental variables from species assemblage data. The ensuing multivariate calibration problem appears to be even harder than that of spectroscopic calibration| primarily because the basic model is unimodal (Shelford's law of tolerance) instead of being linear (Beer's law). The strong non-linearity has led to the use of non-parametric calibration methods| in particular the smooth response surface method (SRS) and the method of best modern analogues| alias k-nearest neighbours (k-NN)| and to a form of non-linear partial least squares (PLS)| called weighted averaging partial least squares (WA-PLS)| specially designed to analyze unimodal data. SRS and k-NN are recognized as non-parametric smoothing versions of the classical and inverse approach to linear calibration| respectively| whereas PLS and WA-PLS are inverse methods that bring in the aspect of dimension reduction. In a comparison on 'realistically looking' simulated compositional data with 100 training samples and 500 independent evaluation samples| WA-PLS and k-NN outperformed PLS when the species response functions were unimodal. For such data| k-NN resisted the curse of dimensionality. However| when the response functions were near-linear| WA-PLS and PLS performed about equally and clearly outperformed k-NN. On other simulated data| simultaneous calibration of two climate variables via a parametric non-linear classical method was compared with individual calibrations via inverse methods. The simultaneous calibration method was better at the border of the sampled space than the best inverse method (WA-PLS) and much better than k-NN. The simulations demonstrated the limitations of the leave-one-out estimate of prediction error: it showed severe method-dependent bias. 4409,1995,3,3,NUCLEAR-ENERGY| ENVIRONMENTAL-PROBLEMS AND THE HYDROGEN ENERGY ECONOMY,Transition to the hydrogen energy economy is justified from environmental and energetic viewpoints| its cost is estimated| and various means to finance it| including various synergies| are discussed. Planetary sources of renewable energy (wind| water| sun) are estimated and deemed sufficient to more than replace all fossil fuel. Cost and magnitude of required infrastructure then imply long construction times during which pollution and global warming may have time to become unacceptable. Advantages of energy as a transition facilitator which avoids them are examined| along with means to alleviate public anxieties about its use. The conclusions are that the main obstacles to a healthy hydrogen-based world are less scientific| technical or economic than due to inertia| ignorance| blindness| stupidity| fear and mistaken narrow interests| and that there will be enough time to overcome them if we attack the problems more energetically and each other less so. 4446,1995,3,3,ON THE EVALUATION OF HALOCARBON RADIATIVE FORCING AND GLOBAL WARMING POTENTIALS,Net global warming potentials and instantaneous radiative forcing values that include the cooling from halocarbon-induced ozone destruction have been calculated fbr 14 of the most significant halocarbons. These calculations were performed by incorporating knowledge of direct global warming potentials with an evaluation of the relationship between tropospheric cooling from stratospheric ozone loss and tropospheric halocarbon mixing ratios. The indirect cooling effect is strongly dependent upon the effectiveness of each halocarbon for ozone destruction. Strong net cooling is ascribed to additions of bromocarbon gases| while methyl chloroform and carbon tetrachloride are more nearly climate-neutral| and the CFCs and HCFCs display strong net warming. Consideration of indirect cooling also has important implications for the expected future net halocarbon forcing of the climate system: in the next 20 years| halocarbon radiative forcing is not predicted to decrease as mixing ratios of strongly ozone-depleting gases decline because of faster decreases in radiative cooling than in radiative wanning. Furthermore| continuing production of HFCs as substitutes for CFCs could result in sharply increasing halocarbon radiative heating in the latter part of the 21st century because of the increasing atmospheric burden of these compounds. 2556,1995,3,3,OPTIMAL CO2 CONTROL POLICY WITH STOCHASTIC LOSSES FROM TEMPERATURE RISE,In this paper| we present a new specification of warming cost and incorporate it into an integrated assessment model of global climate change. In the new specification| warming cost is represented as the product of possible large warming related welfare losses which occur with small probabilities that depend on the amount of temperature rise. This is in contrast to the conventional representation of warming cost as a deterministic function of temperature rise. To avoid 'curse of dimensionality' problems| we assume that losses affect the utility of consumption without directly affecting consumption itself| and that the probability of losses occurring is independent of the number of losses that may have previously occurred. The results we obtain using this new approach depend importantly on the specification of the loss probability function. Nevertheless| our results are qualitatively similar to previous results obtained using a deterministic specification of warming cost| in which cost is a cubic function of temperature rise. 4386,1995,5,4,ORGANIC-CARBON EXHUMATION AND GLOBAL WARMING DURING THE EARLY HIMALAYAN COLLISION,Organic carbon eroded and oxidized from marine sediments on the passive and active neo-Tethyan margins during the early Indian-Asian collision may have been sufficient to shift the carbon isotopic ratios of late Paleocene-early Eocene marine carbonates toward lighter values| and may have contributed to coeval global warming via the greenhouse effect. New limits on the timing of collision and the organic carbon content of Himalayan sedimentary sources and sinks allow us to estimate the net Paleogene flux. Our calculations suggest that continental collisions play a fundamental role in the global carbon cycle and climate through the exhumation as well as burial of organic carbon. 2575,1995,4,4,OUTCOME AND VALUE UNCERTAINTIES IN GLOBAL-CHANGE POLICY,Choices among environmental policies can be informed by analysis of the potential physical| biological| and social outcomes of alternative choices| and analysis of social preferences among these outcomes. Frequently| however| the consequences of alternative policies cannot be accurately predicted because of substantial 'outcome uncertainties' concerning physical| chemical| biological| and social processes linking policy choices to consequences. Similarly| assessments of social preferences among alternative outcomes are limited by 'value uncertainties' arising from limitations of moral principles| the absence of economic markets for many environmental attributes| and other factors. Outcome and value uncertainties relevant to global-change policy are described and their magnitudes are examined for two cases: stratospheric-ozone depletion and global climate change. Analysis of information available in the mid 1980s| when international ozone regulations were adopted| suggests that contemporary uncertainties surrounding CFC emissions and the atmospheric response were so large that plausible ozone depletion| absent regulation| ranged from negligible to catastrophic| a range that exceeded the plausible effect of the regulations considered. Analysis of climate change suggests that| important as outcome uncertainties are| uncertainties about values may be even more important for policy choice. 4344,1995,3,3,OZONE DEPLETION AND ITS IMPACT ON THE METAL-FINISHING INDUSTRY .1. BACKGROUND,The recent proof that man-made ozone depleting substances (ODSs) are seriously damaging the ozone layer| and the suggestion that they may contribute to the global warming phenomenon| has led to the development of international regulatory controls through the Montreal Protocol. The further tightening of these controls will inevitably result in the virtual disappearance of these solvents over the next years. In the face of rapidly decreasing availability and increasing unit price| many industries are taking a hard look at alternative materials for a range of applications. The first part of this paper provides a background to the harmful effects of the ODSs against which the metal finishing industry has to make important decisions regarding their replacements. Part 2 will consider the options available and indicate some of the consequential actions being undertaken within the metal finishing industry. 4332,1995,4,4,PERMAFROST AND CLIMATE-CHANGE - GEOTECHNICAL IMPLICATIONS,The behaviour of the ground in the cold regions of the world is characterized by freezing and thawing. The porous and particulate nature of soils presents conditions for phase change which lead to their unique properties and behaviour in cold climates. Accordingly| the periodic and unstable nature of atmospheric climate and of surface microclimate produces characteristic disturbances in the near-surface layers of the ground in the cold regions. These include the consequences of melting such as subsidence (thermokarst topography) and instability of slopes (landslides| mud-flows)| as well as the thermodynamic and mechanical effects of freezing| especially frost heave. Frozen soils show temperature-dependent creep (some forms of solifluction and deformation of foundations) and continuing heave (expansion of ground over long periods of time). These effects have important geotechnical implications' for the design of highways| airports| buildings and| notably| pipelines. The complexity of the design problems for major structures| especially pipelines| has not been widely understood. If there is global warming due to anthropogenic emissions of gases this will influence the direction and intensity of the ground disturbances| the nature of which has been recognized over the last three or four decades. However the effects of such warming due to atmospheric climate change will only become apparent over many decades. In the short term they will be masked by other ground temperature changes due to microclimatic effects and to inter-annual variability of climate and weather. Over a period of a century or more| if warming trends continue| there will be important modifications of terrain and physiography. 2542,1995,2,4,Phenology and growth of three temperate forest life forms in response to artificial soil warming,1 Responses of temperate deciduous forest vegetation to artificial soil warming (simulating one component of projected global climate change) were investigated in field plots over two growing seasons| 1992-93. Six replicate plots were established for each of three treatments: heating| disturbance-control| and intact control. Growth and phenology of 26 species of three life forms (12 herbaceous understorey species; six shrub species; eight tree species) were monitored non-destructively in the plots at 20 sampling dates. 2 Phenology of leaf emergence and flower production in saplings was not affected by soil warming. Mature trees and shrubs leafed out slightly earlier and in larger numbers in heated plots. Trees flowered earlier and in higher proportions in the heated plots in 1993. 3 Mean area per leaf per plant and leaf expansion rates in 1992 were greatest in control saplings of Acer pensylvanicum and Fagus grandifolia. Vaccinium corymbosum| a shrub| showed reduced leaf sizes under soil heating. 4 Soil warming significantly enhanced relative diameter growth of woody individuals| especially shrubs| in 1992. This effect was less pronounced in 1993. 5 Species richness was lower in heated plots than in intact control plots at all sampling dates in both years. Disturbed but unheated control plots exhibited the lowest species richness overall. Species richness declined in all plots in 1993. 6 Changes in relative abundance of herbaceous species from 1992 to 1993 were highly variable| and not significantly affected by treatment. Rank abundances of species changed more from 1992 to 1993 in intact control plots than in the other two treatments. 7 Total density (stems m(-2)) of herbaceous species was highest in heated plots during April and May of both years| reflecting accelerated emergence of Maianthemum canadense and Uvularia sessilifolia. From June through October| however| intact control plots exhibited the highest stem densities| as numbers of the early emergents declined. 8 Photosynthetic rates of the dominant herbs| Maianthemum canadense and Uvularia sessilifolia| were not significantly affected by heating. 9 Of all life forms| herbaceous species were most sensitive to soil warming. Their early appearance could influence carbon and nutrient acquisition dynamics under changed climatic conditions in deciduous forests. 4346,1995,3,4,PHOTOSYNTHETIC PERFORMANCE OF A HELICAL TUBULAR PHOTOBIOREACTOR INCORPORATING THE CYANOBACTERIUM SPIRULINA-PLATENSIS,The photosynthetic performance of a helical tubular photobioreactor (''Biocoil'')| incorporating the filamentous cyanobacterium Spirulina platensis| was investigated. The photobioreactor was constructed in a cylindrical shape (0.9 m high) with a 0.25-m(2) basal area and a photostage comprising 60 m of transparent PVC tubing of 1.6-cm inner diameter (volume = 12.1 L). The inner surface of the cylinder (area = 1.32 m(2)) was illuminated with cool white fluorescent lamps; the energy input of photosynthetically active radiation (PAR| 400 to 700 nm) into the photobioreactor was 2920 kJ per day. An air-lift system incorporating 4% CO2 was used to circulate the growth medium in the tubing. The maximum productivity achieved in batch culture was 7.18 g dry biomass per day [0.51 g.d biomass/L.day| or 5.44 g.d biomass/m(2) (inner surface of cylindrical shape)/day] which corresponded to a photosynthetic (PAR) efficiency of 5.45%. The CO2 was efficiently removed from the gaseous stream; monitoring the CO2 in the outlet and inlet gas streams showed a 70% removal of CO2 from the inlet gas over an 8-h period with almost maximum growth rate. (C) 1995 John Wiley and Sons| Inc. 4392,1995,5,4,PLANT AND MAMMAL DIVERSITY IN THE PALEOCENE TO EARLY EOCENE OF THE BIGHORN BASIN,Abundant plant and vertebrate fossils have been recovered from fluvial sediments deposited in the Bighorn Basin| Wyoming| during the first 13 m.y. of the Tertiary. Here we outline and discuss changes in the composition and diversity of floras and faunas during this period| which includes the recovery of terrestrial ecosystems from the K/T boundary extinctions| and later| during the Paleocene-Eocene transition| the greatest global warming of the Cenozoic. Floral diversity has been studied at three levels of spatial resolution: sub-local (at individual collecting sites)| local (along a single bed or stratigraphic horizon)| and basin-wide (regional). Sub-local diversity shows a moderate increase from the early to late Paleocene| followed by a decrease across the Paleocene/Eocene boundary| then an increase into the later early Eocene. Local heterogeneity was lower in Paleocene backswamp floras| although distinct groups of species dominated in different local fluvial settings such as backswamps and alluvial ridges. Heterogeneity of backswamp forests increased by about 65% from the early to late Wasatchian (early Eocene). The number of plant species inferred from the Bighorn Basin dataset rose gradually from the Puercan to an early Clarkforkian peak of about 40 species| declined sharply to about 25 species by the Clarkforkian/Wasatchian boundary| then rose through the Wasatchian to about 50 species. A regional analysis of mammalian genera shows high turnover and a rapidly increasing number of genera within a million years of the K/T boundary (10-50 genera)| a slight decline to 40 genera by the early Clarkforkian| then an increase from 40 to 75 genera by the late Wasatchian. Our analyses found no major extinctions in mammals during the Paleocene and early Eocene in the Bighorn Basin| but a one-third decrease in the number of plant species at about the Paleocene/Eocene boundary. Rates of taxonomic turnover were much higher for mammals than plants. The diversity trends for plants and mammals show little congruence| implying that the two groups responded in a very different manner to post K/T extinction opportunities. There is also little congruence between plant diversity levels and change in mean annual temperature (MAT) as inferred from foliar physiognomy. 4354,1995,2,4,Possible impacts of global warming on tundra and boreal forest ecosystems: Comparison of some biogeochemical models,Global warming affects the magnitude of carbon| water and nitrogen fluxes between biosphere and atmosphere as well as the distribution of vegetation types. Biogeochemical models| global as well as patch models| can be used to estimate the differences between the mean values of annual net primary production (NPP) for present and for future climate scenarios. Both approaches rely on the prescribed pattern of vegetation types. Structural| rule-based models can predict such patterns| provided that vegetation and climate are in equilibrium. The coupling of biogeochemical and structural models gives the opportunity of testing the sensitivity of biogeochemical processes not only to climatic change but also to biome shifts. Whether the annual mean NPP of a vegetation type increases or decreases depends strongly on the assumptions about a CO2 fertilization effect and nitrogen cycling. Results from our coupled model show that| given that direct CO2 effects are uncertain| (i) average NPP of these northern biomes might decrease under global warming| but (ii) total NPP of the region would increase| due to the northward shift of the taiga biome. 2555,1995,2,4,POSSIBLE MECHANISMS UNDERLYING FLUCTUATIONS IN THE FAR-EASTERN SARDINE POPULATION INFERRED FROM TIME-SERIES OF 2 BIOLOGICAL TRAITS,A cycle of fluctuation in the Far Eastern sardine| Sardinops sagax| population is accompanied by an abrupt drop and recovery of fish size and lipid content of parent fish| which may reflect a phase variation from coastal to oceanic and its reverse. The cycle begins with die survival success of a smaller number of eggs produced by high-quality parents| which is triggered by a global climate change (density independent process)| and finally ends in the survival failure resulting from an overexpansion of an enormous number of fish produced by low-quality parents (density-dependent process). 4289,1995,2,4,Potential effects of global climate warming on brook trout growth and prey consumption in central Appalachian streams| USA,The effects of global warming trends on growth and food consumption rates for a brook trout Salvelinus fontinalis population were simulated with a bioenergetics model. We examined the hypothesis that improved growth conditions during cooler months will offset the opposing effects of extreme temperatures during the summer. Annual growth increments of brook trout were determined from a population in a high elevation stream in West Virginia| USA| and baseline stream temperatures were measured in mid to high elevation streams. The mean annual stream temperature was increased by 2 and 4 degrees C to simulate the effects of climatic warming. Brook trout populations at high elevations in the Appalachian Mountains could either benefit from increased growth rates in spring and fall| or suffer from shrinking habitat and reduced growth rates in summer| depending on the magnitude of temperature change and on food availability. An increase of 2 degrees C or less could very likely increase brook trout growth| but the effect of larger temperature increases is less predictable due to greater dependence on higher prey production. A 15 to 20% increase in food consumption would be required to maintain present rates of growth with an increase of 2 degrees C| and 30 to 40% more food would be required with an increase of 4 degrees C. 2595,1995,2,3,POTENTIAL EFFECTS OF GLOBAL CLIMATIC-CHANGE ON THE PHENOLOGY AND YIELD OF MAIZE IN VENEZUELA,Simulated impacts of global and regional climate change| induced by an enhanced greenhouse effect and by Amazonian deforestation| on the phenology and yield of two grain corn cultivars in Venezuela (CENIAP PB-8 and OBREGON) are reported. Three sires were selected: Turen| Barinas and Yaritagua| representing two important agricultural regions in the country. The CERES-Maize model| a mechanistic process-based model| in the Decision Support System for Agrotechnology Transfer (DSSAT) was used for the crop simulations. These simulations assume non-limiting nutrients| no pest damage and no damage from excess water; therefore| the results indicate only the difference between baseline and perturbed climatic conditions| when other conditions remain the same. Four greenhouse-induced global climate change scenarios| covering different sensitivity levels| and one deforestation-induced regional climate change scenario were used. The greenhouse scenarios assume increased air temperature| increased rainfall and decreased incoming solar radiation| as derived from atmospheric GCMs for doubled CO2 conditions. The deforestation scenarios assume increased air temperature| increased incoming solar radiation and decreased rainfall| as predicted by coupled atmosphere-biosphere models for extensive deforestation of a portion of the Amazon basin. Two baseline climate years for each site were selected| one year with average precipitation and another with lower than average rainfall. Scenarios associated with the greenhouse effect cause a decrease in yield of both cultivars at all three sites| while the deforestation scenarios produce small changes. Sensitivity tests revealed the reasons for these responses. Increasing temperatures| especially daily maximum temperatures| reduce yield by reducing the duration of the phenological phases of both cultivars| as expected from CERES-Maize. The reduction of the duration of the kernel filling phase has the largest effect on yield. Increases of precipitation associated with greenhouse warming have no effects on yield| because these sites already have adequate precipitation; however| the crop model used here does not simulate potential negative effects of excess water| which could have important consequences in terms of soil erosion and nutrient leaching. Increases in solar radiation increased yields| according to the non-saturating light response of the photosynthesis rate: of a C-4 plant like corn| compensating for reduced yields from increased temperatures in deforestation scenarios. In the greenhouse scenarios| reduced insolation (due to increased cloud cover) and increased temperatures combine to reduce yields; a combination of temperature increase with a reduction in solar radiation produces fewer and lighter kernels. 2579,1995,2,2,POTENTIAL IMPACT OF GLOBAL CLIMATE-CHANGE ON MALARIA RISK,The biological activity and geographic distribution of the malarial parasite and its vector are sensitive to climatic influences| especially temperature and precipitation. We have incorporated Genera Circulation Model-based scenarios of anthropogenic global climate change in an integrated linked-system model for predicting changes in malaria epidemic potential in the next century. The concept of the disability-adjusted life years is included to arrive at a single measure of the effect of anthropogenic climate change on the heath impact of malaria Assessment of the potential impact of global climate change on the incidence of malaria suggests a widespread increase of risk due to expansion of the areas suitable for malaria transmission. This predicted increase is most pronounced at the borders of endemic malaria areas and at higher altitudes within malarial areas. The incidence of infection is sensitive to climate changes in areas of Southeast Asia| South America| and parts of Africa where the disease is less endemic; in these regions the numbers of years of healthy life lost may increase significantly. However| the simulated changes in malaria risk must be interpreted on the basis of local environmental conditions| the effects of socioeconomic developments| and malaria control programs or capabilities. 4317,1995,2,4,POTENTIAL IMPACTS OF CLIMATIC-CHANGE ON NATURAL FORESTS AND FORESTRY IN BRAZILIAN AMAZONIA,Climatic change can have significant impacts on tropical forests. Of greatest concern in Brazil is potential alteration of the hydrological cycle in Amazonia as a result of reduction in evapotranspiration that could be expected from a continuation of present deforestation trends. Other possible changes in Amazonia are more speculative| but merit research to better assess their likelihood of occurrence and potential severity. These include possible increased cloudiness in the northeast corner of the region (decreasing primary productivity there)| increased tree mortality throughout the region as a consequence of differential stimulation of vine growth by carbon dioxide (CO|) enrichment| increased carbon uptake by some tree species stimulated by CO| enrichment| and a variety of possible indirect effects of increased drought severity and frequency. Changes in temperature and rainfall as a result of global warming are expected to be slight at equatorial latitudes| but some changes could occur. While global warming changes imply expansion of the area climatically suitable for tropical forest| human activity converting these lands to uses other than tropical forests makes it unlikely that much| if any| of the potential for forest expansion would be realized. Human impacts on Brazil's Amazonian forests are great| and can be expected to respond to changes stemming from population growth and migration| economic activity and development policies. Some of the human impacts on forests will be affected by climatic changes in other parts of Brazil and in other parts of the world. Brazil is fortunate in having large areas of natural forest. This area| together with Brazil's large area of land not currently forested that is suitable for silvicultural plantations| makes the country relatively secure in supplying its own needs for forest products-at least through the year 2050-despite possible erosion of forest resources by climatic change. Many other countries are not so fortunate| and Brazil's capacity to supply forest products to the rest of the world is finite. 4394,1995,2,3,POTENTIAL IMPACTS OF GLOBAL WARMING ON THE FREQUENCY AND MAGNITUDE OF HEAVY PRECIPITATION,It is now widely recognised that the most significant impacts of global warming are likely to be experienced through changes in the frequency of extreme events| including flooding. This paper reviews physical and empirical arguments which suggest that global warming may result in a more intense hydrological cycle| with an associated increase in the frequency and/or magnitude of heavy precipitation. Results derived from enhanced-greenhouse experiments using global climate models (GCMs) are shown to be consistent with these physical and empirical arguments. Detailed analysis of output from three GCMs indicates the possibility of substantial increases in the frequency and magnitude of extreme daily precipitation| with amplification of the effect as the return period increases. Moreover| return period analyses for locations in Australia| Europe| India| China and the USA indicate that the results are global in scope. Subsequent discussion of the limitations of GCMs for this sort of analysis highlights the need for caution when interpreting the precipitation results presented here. However| the consistency between physically-based expectations| empirical observations| and GCM results is considered sufficient for the GCM results to be taken seriously| at least in a qualitative sense| especially considering that the alternative seems to be reliance by planners on the fundamentally flawed concept of a stationary climate. 2567,1995,2,4,Potential shifts in optimum growth areas of selected commercial tree species and subtropical crops in southern Africa due to global warming,The area under agricultural production in southern Africa is declining as a result of industrial expansion| mining as well as formal and informal urbanization. Simultaneously| the increasing demand for timber products will necessitate a doubling of the present area under commercial afforestation in South Africa over the next 30 years. Potentially afforestable areas| however| frequently occur in the same climatic belts as certain subtropical fruit crops. Given the climatic constraints for optimum growth of commercially afforestable timber species and subtropical horticultural crops| that southern Africa is a largely semi-arid region| the fact that the areal extent of land available for agriculture is shrinking| together with the uncertainties and possible threats linked with anticipated global climate change| the identification of land areas suitable for future expansion of plantations and subtropical crops requires careful assessment. The spatial distributions of areas suited climatically to optimum growth of two commercial tree species| Eucalyptus grandis and Pinus patula| and two subtropical crops| avocado and pecan nut| were mapped for southern Africa using a climate threshold approach in conjunction with detailed gridded climate information bases| for both the present climate and for a possible future climate scenario. Results indicate that the possible impacts of a future temperature-increase on the spatial distributions of optimum growth areas is species dependent| favouring E. grandis| avocado and pecan nut| but not P. patula. According to the climatic threshold model used| the timber species and horticultural crops considered produced a westward shift to 'new' climatically suitable areas in the future. The results also indicate that climate change resulting from the augmented greenhouse effect may benefit the horticultural industry to a greater extent than the timber industry. Hence| competition for land suitable for future expansion of certain commercial tree species and subtropical crops may become an important consideration in the future. 4445,1995,2,4,POTENTIALITIES| UNCERTAINTIES AND COMPLEXITIES IN THE RESPONSE OF CORAL-REEFS TO FUTURE SEA-LEVEL RISE,Coral islands formed of largely unconsolidated sands only a few metres above sea level are thought to be particularly vulnerable to sea-level rise consequent upon global warming. However| scenarios which predict catastrophic flooding and loss of island area need reassessment| particularly in the light of the continued downwards revision of projected rates of future sea-level rise. Revised questions concern the interactions between reef growth and sea-level change| biophysical constraints on coral growth| and the importance to reef systems of potential changes in the magnitude| frequency and location of tropical cyclones and hurricanes. It is clear that most reefs have the growth potential to meet even the highest of future sea-level rise scenarios| but too little is known about physiological and physical constraints to reef growth to adequately evaluate the importance of these two factors in constraining this potential at the present time. Future sea-level rise in the tropical oceans| and coral reef responses| will take place against a backdrop of inter-regional differences in Holocene sea levels| resulting from the varying interaction of eustatic and hydro-isostatic processes. These differences have generated varying constraints on the development of modern reefs and varying inherited topographies upon which future sea-level changes will be superimposed. These controls are particularly important in assessing differences in vulnerability to future sea-level rise for reef islands in the Pacific Ocean and the Caribbean Sea. 4399,1995,4,4,PRACTICE AND PROGRESS IN INTEGRATED ASSESSMENTS OF CLIMATE-CHANGE - A WORKSHOP OVERVIEW,This paper is intended to provide an overview of the state of the art integrated socioeconomic-biophysical assessments of climate change as presented at the IIASA workshop in October 1993| The paper seeks to tally the major improvements facilitated by integrated assessments in understanding the global warming problem and the crucial unresolved problems they currently face| The basic conclusion is that| as a result of a healthy diversity in practice| integrated assessments show significant progress in structuring the economic issues of climate change and providing the first broad insights into policy options| But| as some of the simple and traditional cases seem to be solved| more complex and difficult contingencies come to the fore| This suggests a long way to go to develop skills that will be required to address the numerous open issues. 4340,1995,4,5,PRECISION GLOBAL TEMPERATURES FROM SATELLITES AND URBAN WARMING EFFECTS OF NON-SATELLITE DATA,Data sets designed for operational use are now being employed to monitor the earth on decadal time scales| an application outside of their original purpose. One data set| from the Microwave Sounding Unit| measures atmospheric temperature in deep layers since late 1978. Procedures for verifying and validating these data by two tests are presented: one by comparison with an independent satellite and one by comparison with radiosonde data. The results show that data from such an instrument are precise and therefore ideal for global studies. Temperatures measured by surface thermometers have considerable error for long-term studies because of various factors. Widely varying results are shown for California stations| where the few sites chosen for global temperature trend estimation are shown not to be representative of the average trend measured by over 100 stations in the state. Such a result calls into question the ability of scattered| selected surface networks to provide a true picture of long-term trends. The global temperature trend of the lower troposphere measured by the Microwave Sounding Units from January 1979 to March 1994 is -0.06 degrees C per decade. 4377,1995,2,3,PREDICTING THE EFFECTS OF CLIMATE-CHANGE ON FIRE FREQUENCY IN THE SOUTHEASTERN CANADIAN BOREAL FOREST,Although an increasing frequency of forest fires has been suggested as a consequence of global warming| there are no empirical data that have shown climatically driven increases in fire frequency since the warming that has followed the end of the ''Little Ice Age'' (similar to 1850). In fact| a 300-year fire history (AD 1688-1988) from the Lac Duparquet area (48 degrees 28'N| 79 degrees 17'W) shows a significant decrease both in the number and extent of fires starting 100 years ago during a period of warming. To explore this relationship between climatic change and fire frequency we used daily data from the Canadian Atmospheric Environment Service's General Circulation Model to calculate components of the Canadian Forest Fire Weather Index (FWI) System for the 1xCO(2) and 2xCO(2) scenarios. The average FWI over much of eastern Canada| including the Lac Duparquet region| decreased under the 2xCO(2) simulation| whereas FWI increased dramatically over western Canada. According to these results| fire frequency would decrease over the southeastern boreal forest which is in agreement with the empirical data from the fire history. Our results stress the importance of large regional variability and call into question previous generalisations suggesting universal increases in the rate of disturbance with climate warming. 4361,1995,3,3,PRODUCTION AND SELECTION OF SOMACLONAL VARIANTS OF LEUCAENA-LEUCOCEPHALA WITH HIGH-CARBON DIOXIDE ASSIMILATING POTENTIAL,Callus was induced from various explants of Leucaena leucocephala| a fast growing| multipurpose| leguminous tree species. Callus obtained from hypocotyl segments showed high morphogenetic potential. Caulogenesis was achieved on B-5 medium supplemented with 6-benzylamino purine. Presence of ac-naphthaleneacetic acid in the medium promoted 6-benzylamino purine induced caulogenesis. Callus obtained from hypocotyl segments retained the capacity to produce shoots upon subculturing even after four months from induction. The shoots obtained from callus were transferred to auxin containing media for rooting. Good root induction was achieved in the presence of 10(-6)M 3-indolebutyric acid. Various morphologically distinct somaclonal variants were exposed to high concentrations of carbon dioxide. Somaclonal variants capable of growing well in the presence of high levels of carbon dioxide were selected. The majority of such variants were found to have high carbon dioxide assimilating capacity (as indicated by infra red gas analysis). Simultaneously methods were standardised for rapid multiplication of Leucaena leucocephala through apical bud and nodal cultures. Best apical bud and axillary bud sprouting was achieved on B-5 medium supplemented with 6-benzylaminopurine. Subsequent to multiplication| the efficient carbon dioxide assimilating variants can be used for afforestation and reforestation purposes in barren lands. This is likely to be one of the best methods| that can be employed safely| for alleviating the problem of global warming. 4292,1995,3,2,Radiative effects and halocarbon global warming potentials of replacement compounds for chlorofluorocarbons,Instantaneous radiative forcing was calculated for 5 fluoroalcohols| 21 fluoroethers| and 5 fluoroamines which had been proposed as the replacement compounds for the currently used chlorofluorcarbons (CFCs) in refrigeration. Theatmospheric lifetimes of the compounds were also estimated from highest-occupied molecular orbital (HOMO) energy. Based on the radiative forcing and atmospheric lifetimes| halocarbon global warming potentials (HGWPs) were evaluated for the replacement compounds. Most of the HGWP values were smaller than 0.1 owing to their shorter lifetimes| and the results indicate that these compounds could be valid candidates as replacements for currently used CFCs from the point of view of HGWP. The spectral cooling rate profiles were calculated for the replacement compounds in order to study the vertical structure of their radiative effects. It was found that overlapping of the absorption bands of a compound with those of ozone causes a significant cooling in the stratosphere| even if the compound does not exist in the stratosphere. This cooling does not directly relate to the HGWP value and the cooling rate profile in the troposphere. Therefore| it can be said that the vertical structure of the radiative effects caused by the compounds should be taken into consideration as well as HGWP or GWP values when we assess the environmental effects due to replacement compounds. In this study| one parameter| defined as the ratio of the cooling rate at 30 km and the tropopause| was proposed as a measure of the cooling in the stratosphere. Spectral-resolution dependency of the calculated radiative effects was also studied. The results show that the resolution should be finer than about 50 cm(-1) to calculate the radiative forcing and cooling rate precisely. 4306,1995,4,4,RADIATIVE FORCING OF CLIMATE BY HYDROCHLOROFLUOROCARBONS AND HYDROFLUOROCARBONS,We measure infrared absorption spectra of 18 hydrochlorofluorocarbons and hydrofluorocarbons| seven of which do not yet appear in the literature. The spectra are used in a narrowband model of the terrestrial infrared radiation to calculate radiative forcing and global warming potentials. We investigate the sensitivity of the radiative forcing to the absorption spectrum temperature dependence| halocarbon vertical profile| stratospheric adjustment| cloudiness| spectral overlap| and latitude| and we make some recommendations for the reporting of radiative forcings that would help to resolve discrepancies between assessments. We investigate simple methods of estimating instantaneous radiative forcing directly from a molecule's absorption spectrum and we present a new method that agrees to within 0.3% with our narrowband model results. 2568,1995,5,4,RADIOCARBON AGES ON ORGANICS FROM PIEDMONT ALLUVIUM| AJO MOUNTAINS| ARIZONA,Alluvium in dry lands is considered difficult to date by radiocarbon methods because of the paucity of organic matter. Although organic materials of sufficient size for conventional C-14 dating are rare| wet sieving of alluvium in the Sonoran Desert yields sufficient organics for C-14 measurements by accelerator mass spectrometry (AMS). Detrital charcoal from two Quaternary fluvial fill terraces on the western side of the Ajo Mountains yielded C-14 ages of 14|880 +/- 70 yr B.P. (CAMS-12408) for the Qt 1 terrace and 2490 +/- 60 yr B.P. (CAMS-12414) and 2510 +/- 60 yr B.P. (CAMS-12415) for the smaller inset Qt 2 terrace. These C-14 ages are consistent with what is known about rates of soil development in the region. The earlier aggradation event appears to be supported by regional and possibly global climate change at about 14|000 C-14 yr B.P. The more recent aggradation event does not appear to be synchronous with periods of frequent paleofloods in the southwest. The offset between C-14 and Cl-36 ages for the same terraces provides a general indication of the time taken for the clasts to be transported to their current positions on the terraces. 4381,1995,3,3,REDUCING THE FORMATION OF CARBON OXIDES IN THE PRODUCTION OF C-2 HYDROCARBONS FROM METHANE,Methane is the main component of natural gas and has been connected with global warming. The oxidative coupling of methane has been studied to enhance C-2 hydrocarbon selectivity and to reduce the formation of carbon oxides associated with C-2 hydrocarbon production. Acid sites of supported catalysts play a role in the formation of carbon oxides. The supported Zn oxide catalyst with alpha-Al2O3 shows no acidity in temperature programmed desorption by using NH3 and exhibits good C-2 hydrocarbon selectivity. The optimum loading of Zn oxide on alpha-Al2O3 is 60 wt%. The specific surface area of the catalyst appears not to influence activity. Using alkali metal salts as promoter in Zn oxide (60 Wt%)/alpha-Al2O3 catalyst| the activity performance for C-2 hydrocarbon formation is LiCl > NaCl > KCl: the performance is well correlated with the apparent molal enthalpy of formation of halides. The activity performance for minimizing carbon oxides is LiCl > KCl > NaCl| which is well correlated with the melting points in alkali halides. 2605,1995,4,4,REMOTE-SENSING OF VOLCANOS AND THEIR ROLE IN THE GLOBAL CLIMATE-CHANGE,The literature on remote sensing of volcanoes is in general mainly concerned with some basic morphological features| suitable for eruption warning and for detecting plumes and lava flows. The present paper aims| rather| to emphasize the physical processes related to the role of volcanoes in the global climate change. In particular| the actual time-varying role of volcanoes has to be assessed in the degassing process of the Earth. Some relevant information can be got from the past (historic and palaeontological)| for envisaging what should be monitored by satellite at present. 4365,1995,3,3,RESEARCH OF ARID-LAND AFFORESTATION TECHNOLOGIES FOR CARBON-DIOXIDE FIXATION,As part of measures against the global warming| The Japan Gas Association established jointly with Research Institute of Innovative Technology for the Earth (RITE)| ''Society for Research of Desert Greening as a Measure against CO2 ''. The work of the society is proposing a research and development outline of realization of desert greening as a measure against CO2 global warming| and investigation and research work was conducted to make the proposal. As the result| the basic ideas of arid land afforestation for CO2 control| were found out to be the following. (1) To make it effective toward reducing global warming| fixing more than one hundred million tons of CO2 is necessary. (2) To achieve the fixation| an afforestation scale of 100 km x 100 km is necessary. (3) CO2 fixation should be continued for a long period| about 100 years. Based on these ideas| Basic Concept of R and D Activities for Realizing Deserts Afforestation which is consist of three main subjects of (1) designing of overall system of and land afforestation|(2) establishment of individual technologies|and (3) Evaluation of the system| is proposed. 2583,1995,2,3,RESPONSES OF BLACK SPRUCE SEEDLINGS TO SIMULATED PRESENT VERSUS FUTURE SEEDBED ENVIRONMENTS,We investigated the effects of nitrogen availability and present versus future atmospheric environments (i.e.| climate) on the seedling performance of 16 open-pollinated maternal families of Picea mariana (Mill.) B.S.P. over two simulated growing seasons. Diurnal and seasonal patterns of temperature| relative humidity| photoperiod| and light intensity were simulated. The simulated future climate included both elevated CO2 and seasonally appropriate increases in mean monthly temperatures. Compared with the present| the future climate increased seedling survival| total and root dry mass| rate of winter bud development| net photosynthetic rate| and water and nitrogen use efficiencies; decreased needle nitrogen content; and altered biomass allocation patterns. Greater nitrogen availability greatly improved seedling performance and changed biomass allocation patterns. Climate and nitrogen level interacted synergistically to promote seedling growth (branch number and root dry mass)| survival| and bud development. The future climate increased seedling survival| rate of bud development| and nitrogen use efficiency much more in the low than in the high nitrogen regime. Seedling performance in the second season was dependent on initial seed mass| but less than in the 1st year. Some of the differences among the families and in their interactions with the climate and (or) nitrogen fertilization suggest that families selected for rapid growth under present conditions may not do well in the future| at least in terms of early establishment. Forest managers and tree breeders should take this possibility into consideration in their tree improvement and reforestation programs. 4373,1995,4,4,REVIEW AND SYNTHESIS,Studies of trace gases in the atmosphere| their sources| sinks| and mechanisms of transport| have developed rapidly in the last few decades. This has been driven partly by increasing recognition that particular gases are associated with problems such as acidification| eutrophication| and global warming| but also by the developing enthusiasm for multidisciplinary research in which scientists from many disciplines collaborate to explore biological| geochemical| and atmospheric cycles and to understand how human action disturbs such cycles. Major international programs such as the International Biological Program (IBP) and the International Geosphere-Biosphere Program (IGBP) have been very influential in generating and encouraging this new way of working. To answer these complex environmental research questions| scientists have needed to develop new field instrumentation| or at least to modify instruments normally used in the laboratory. Equally| mathematical simulation models are increasingly being used at scales ranging from cellular to global to allow complex computations that would have been unthinkable even a decade ago. The papers in this proceedings illustrate some of the exciting developments taking place in the study of the exchange of trace gases between the atmosphere and the land. They describe new understanding of the processes in soils| plants and the atmosphere that control gases important in the carbon and nitrogen cycles| they summarize new techniques and instrumentation that allow field studies at scales ranging from soil grains to landscapes| and they present results of mathematical models that allow us to explore consequences of global changes that may yet come. 2558,1995,3,3,Road map or false trail? Evaluating the ''precedence'' of the ozone regime as a model and strategy for global climate change,The amended 1987 Montreal Protocol stands at the center of an international regime designed to protect stratospheric ozone. Analysts and policy makers cite the regime's global scope| innovative characteristics| and extant success as breakthroughs in environmental cooperation and possible blueprints for other international environmental agreements| including climate change. Surprisingly| there has been little detailed research to determine if and how the development of the ozone regime actually is or is not a precedent for creating effective agreements on global climate change. This article begins such an analysis. I provide a framework for research into this issue| draw preliminary conclusions| and highlight areas requiring further research. I begin by delineating four propositions concerning the precedence of the ozone regime. I then distill and provide preliminary analysis of three issues| or research questions| that must be examined in order to determine the validity and policy relevance of two of these propositions.
2560,1995,3,3,ROLE OF RUSSIAN FORESTS IN THE GLOBAL CARBON BALANCE,The significance of terrestrial ecosystems to global climate change will not be fully recognized until all components which contribute to their flux are accurately quantified. The absence of a common approach to quantify terrestrial carbon has resulted in substantial discrepancies in regional| national| and global estimates of carbon. One of the most dramatic cases is represented by the flux estimates for Russian forests which differ both in character and by two orders of magnitude. A system of accounting which provides a comprehensive estimate of the carbon flux between Russian forests and the atmosphere is presented herein. All significant components of the carbon cycle in forest ecosystems are considered. The sequestration of carbon in Russian forests is substantial| In the late 1980s and early 1990s| Russian forests were accumulating 0.66 Pg C yr(-1). Approximately one-third of the sequestered carbon was returned to the atmosphere through logging and forests fires. 2586,1995,2,2,SCENARIO ANALYSIS OF GLOBAL WARMING USING THE ASIAN-PACIFIC INTEGRATED MODEL (AIM),The Asian Pacific Integrated Model (AIM) is a large-scale model for scenario analyses of greenhouse gas (GHG) emissions and the impacts of global warming in the Asian Pacific region| The AIM comprises two main models - the AIM/emission model for predicting GHG emissions and the AIM/impact model for estimating the impacts of global warming - which are linked by the global GHG cycle and the climate change models| This paper categorizes the scenarios that have been written so far in relation to global warming| and then| given fixed inputs| simulates the effects of global warming taking into account various uncertainties| Several recent outcomes from the AIM/impact model are then described| Assuming climate change scenarios deduced from AIM/emission and GCM experiments| primary impacts on water resources and natural vegetation are assessed. 2550,1995,3,3,SCENARIOS FOR MITIGATING GREENHOUSE GASES EMISSIONS AND PROMOTING SUSTAINABLE ENERGY DEVELOPMENT IN BRAZIL,This work presents the methodology and results of a study carried out by the Energy and Environmental Planning Program of the Center for Postgraduate Studies in Engineering of the Federal University of Rio de Janeiro (PPE/ COPPE/UFRJ). An estimate elaborated by PPE/COPPE/UFRJ of Brazilian CO2 emissions due to energy consumption from 1970 to 1990 is presented initially. It is shown that Amazon deforestation is today the largest contributor to the greenhouse effect in Brazil| In the long run| however| emissions from the energy system (due to the burning of oil products| natural gas| coal and coke| wood| and charcoal) are bound to increase and overtake CO| emissions from deforestation. This study evaluates three scenarios of the long-run evolution of Brazilian economic and energy sectors; the scenarios were formulated by PPE/COPPE/UFRJ. The possibility of halving future CO2 emissions (resulting from fossil fuel energy consumption) with small increases of costs and investments linked to the energy sector is illustrated. This abatement scenario would require dramatic efforts to promote energy conservation On the supply side of the Brazilian energy balance| efforts would need to be made to promote the use of alternative fuels such as hydropower| ethanol and bagasse from sugar cane| wood and charcoal from afforestation programmers. However| recent trends in Brazilian energy policy do not coincide with the above abatement scenario due to the lack of ability to fund capital-intensive projects. The transfer of an adequate amount of financial resources from industrialized countries in appropriate soft terms is thus required in order for the Brazilian energy system to curb the greenhouse effect. Vast opportunities exist for a positive working relationship between both sustainable energy development strategies derived from national objectives and the prevention of global climate change. To this end| policies to tap the renewable energy potential should include appropriate measures to minimize any negative social and ecological impacts at the local and regional levels| as well as demonstrating their economic cost-effectiveness. Mechanisms adopted to implement the Convention on Global Climate Change signed an June 1992 during the United Nations Conference on Environment and Development in Rio de Janeiro| such as the Global Environment Facility (GEF)| should support the viability of these strategies in Brazil| as well as in other developing countries. 4434,1995,2,4,SEA-LEVEL RISE - A REVIEW OF RECENT PAST AND NEAR-FUTURE TRENDS,Global mean sea level is a potentially sensitive indicator of climate change. Global warming will contribute to worldwide sea-level rise (SLR) from thermal expansion of ocean water| melting of mountain glaciers and polar ice sheets. A number of studies| mostly using tide-gauge data from the Permanent Service for Mean Sea Level| Bidston Observatory| England| have obtained rates of global SLR within the last 100 years that range between 0.3 and 3 mm yr(-1)| with most values concentrated between 1 and 2 mm yr(-1). However| the reliability of these results has been questioned because of problems with data quality and physical processes that introduce a high level of spatial and temporal variability. Sources of uncertainty in the sealevel data include variations in winds| ocean currents| river runoff| vertical earth movements| and geographically uneven distribution of long-term records. Crustal motions introduce a major source of error. To a large extent| these can be filtered by employing palaeo-sea-level proxies| and geophysical modelling to remove glacio-isostatic changes. Ultimately| satellite geodesy will help resolve the inherent ambiguity between the land and ocean level changes recorded by tide gauges. Future sea level is expected to rise by similar to 1 m| with a 'best-guess' value of 48 cm by the year 2100. Such rates represent an acceleration of four to seven times over present rates. Local land subsidence could substantially increase the apparent SLR. For example| Louisiana is currently experiencing SLR trends nearly 10 times the global mean rate. These recently reduced SLR estimates are based on climate models that predict a zero to negative contribution to SLR from Antarctica. Most global climate models (GCMs) indicate an ice accumulation over Antarctica| because in a warmer world| precipitation will exceed ablation/snow-melt. However| the impacts of attritional processes| such as thinning of the ice shelves| have been downplayed according to some experts. Furthermore| not all climate models are in agreement. Opposite conclusions may be drawn from the results of other GCMs. In addition| the West Antarctic Ice Sheet is potentially subject to dynamic and volcanic instabilities that are difficult to predict. Because of the great uncertainty in SLR projections| careful monitoring of future sea-level trends by upgraded tide-gauge networks and satellite geodesy will become essential. Finally| because of the high spatial variability in crustal subsidence rates| wave climates and tidal regimes| it will be the set of local conditions (especially the relative sea-level rise)| rather than a single global mean sea-level trend| that will determine each locality's vulnerability to future SLR. 2594,1995,2,4,SEASONALITY OF FLOWERING AND FRUITING IN TEMPERATE FOREST TREES,The phenology of leaf presence and photosynthetic activity together set a potential limit on tree productivity in a seasonal climate; similarly| the seasonal timing of flowering and fruiting can decide tree reproductive success. The capacity for long-term storage of photosynthate appears to override any necessary functional linkage between these two critical aspects of tree phenology. Foliar and reproductive phenology in broadleaf deciduous trees of the temperate zone are only weakly coupled within a growing season| especially in precocious flowering trees that mature their fruits in early summer. In species that fruit in late summer and fall| leaf emergence and flowering can be entrained by shared responses to the progressive warming of early spring but with only limited effect on the timing of fruit maturation. The timing of foliar senescence and fruit maturation is correlated only in fall-fruiting trees but as a common response to fall climate rather than the outcome of foliar retranslocation of resources to developing fruits. The possibility exists that global climate change may disrupt these patterns of foliar and reproductive phenology| but the magnitude of the effect will depend on the poorly studied balance of thermal versus photoperiodic cues for phenological events. 4457,1995,2,4,SEDIMENTARY RECORDS OF RECENT ENVIRONMENTAL-CHANGE IN LAKE BAIKAL| SIBERIA,Lake Baikal is the world's largest freshwater lake and is internationally famous for its rich and largely endemic biota. Concern about this unique ecosystem has grown since the late 1970s but whether recent biological changes result from natural fluctuations or pollution is unclear. One way of discriminating between these processes is to examine records of recent change in radiometrically dated deep-water sediment cores. Here we use high-resolution diatom analysis of one core to show that abundances have not changed significantly over recent decades. By contrast| we demonstrate that the lake is contaminated by atmospheric pollutants and has experienced a small qualitative change in soil derived magnetic minerals. Sedimentary lead concentrations show an increasing trend in the c. 150-year core sequence and spheroidal carbonaceous particles (SCPs) contaminate post-1930 sediment. Although we provide no evidence that twentieth-century pollution has affected the endemic planktonic diatoms in the central western region of southern Lake Baikal| longer trends in species abundances could be related to naturally occurring climatic cycles or to global warming. 4468,1995,2,3,SENSITIVITY OF 4 WHEAT SIMULATION-MODELS TO CLIMATE-CHANGE,Crop simulation models may be valuable in anticipating crop production under a changed climate. We compared four computer simulation models of wheat| crop estimation through resources and environment synthesis (CERES)| erosion productivity impact calculator (EPIC)| Stewart and Sinclair| for evaluating the impact of climate change on dryland spring wheat yield for continuous rotation in southern Alberta. To a varying extent| the four models showed decreases in dryland spring wheat yields due to high temperature and low precipitation. All the models except Stewart had similar sensitivity to low precipitation; however| they showed differences to high-moisture conditions. Within the range considered| the Sinclair model was the most sensitive to temperature| followed by CERES and Stewart. Only EPIC indicated optimum temperature and precipitation levels| while CERES had the most pronounced precipitation optimum. Although the CERES| Stewart and Sinclair models have different phenology submodels| they predicted similar phenological response to a doubled CO2 climate scenario generated from the Canadian Climate Center General Circulation Model for Lethbridge| AB. Growing seasons shortened by 19 d were predicted using CERES and 18 d by using the Sinclair and Stewart models. The CERES| Stewart and Sinclair models were modified to include the effect of CO2 on radiation-use-efficiency. With current atmospheric CO2 concentration in the future climate scenario| the EPIC and Stewart models predicted significant (25%) and non-significant (3%) yield increases for dryland wheat and Sinclair and CERES predicted yield losses. Higher CO2 levels may compensate for the effect of global warming; doubling CO2 from present levels in a warmer climate scenario resulted in yield increase predictions at different amplitudes using EPIC| Stewart and CERES and a slight yield decrease with Sinclair. 4397,1995,2,4,SENSITIVITY OF A PRAIRIE WETLAND TO INCREASED TEMPERATURE AND SEASONAL PRECIPITATION CHANGES,We assessed the potential effects of increased temperature and changes in amount and seasonal timing of precipitation on the hydrology and vegetation of a semi-permanent prairie wetland in North Dakota using a spatially-defined| rule-based simulation model. Simulations were run with increased temperatures of 2 degrees C combined with a 10 percent increase or decrease in total growing season precipitation. Changes in precipitation were applied either evenly across all months or to individual seasons (spring| summer| or fall). The response of semi-permanent wetland P1 was relatively similar under most of the seasonal scenarios. A 10 percent increase in total growing season precipitation applied to summer months only| to fall months only| and over all months produced lower water levels compared to those resulting from the current climate due to increased evapotranspiration. Wetland hydrology was most affected by changes in spring precipitation and runoff. Vegetation response was relatively consistent across scenarios. Seven of the eight seasonal scenarios produced drier conditions with no open water and greater vegetation cover compared to those resulting from the current climate. Only when spring precipitation increased did the wetland maintain an extensive open water area (49 percent). Potential changes in climate that affect spring runoff| such as changes to spring precipitation and snow melt| may have the greatest impact on prairie wetland hydrology and vegetation. In addition| relatively small changes in water level during dry years may affect the period of time the wetland contains open water. Emergent vegetation| once it is established| can survive under drier conditions due to its ability to persist in shallow water with fluctuating levels. The model's sensitivity to changes in temperature and seasonal precipitation patterns accentuates the need for accurate regional climate change projections from general circulation models. 4419,1995,4,2,SENSITIVITY OF DIRECT GLOBAL WARMING POTENTIALS TO KEY UNCERTAINTIES,The concept of global warming potential was developed as a relative measure of the potential effects on climate of a greenhouse gas as compared to CO2. In this paper a series of sensitivity studies examines several uncertainties in determination of Global Warming Potentials (GWPs). For example| the original evaluation of GWPs for the Intergovernmental Panel on Climate Change (IPCC| 1990) did not attempt to account for the possible sinks of carbon dioxide (CO2) that could balance the carbon cycle and produce atmospheric concentrations of CO2 that match observations. In this study| a balanced carbon cycle model is applied in calculation of the radiative forcing from CO2. Use of the balanced model produces up to 21% enhancement of the GWPs for most trace gases compared with the IPCC (1990) values for time horizons up to 100 years| but a decreasing enhancement with longer time horizons. Uncertainty limits of the fertilization feedback parameter contribute a 20% range in GWP values. Another systematic uncertainty in GWPs is the assumption of an equilibrium atmosphere (one in which the concentration of trace gases remains constant) versus a disequilibrium atmosphere (one in which the concentration of trace gases varies with time). The latter gives GWPs that are 19 to 32% greater than the former for a 100 year time horizons| depending upon the carbon dioxide emission scenario chosen. Five scenarios are employed: constant-concentration| constant-emission past 1990 and the three IPCC (1992) emission scenarios. For the analysis of uncertainties in atmospheric lifetime (tau) the GWP changes in direct proportion to tau for short-lived gases| but to a lesser extent for gases with tau greater than the time horizontal for the GWP calculation. 2565,1995,2,3,Sensitivity of Inner Mongolia grasslands to climate change,We investigated the effects of global climate change and doubled atmospheric CO2 concentration to plant primary production and soil organic matter of typical steppe (Leymus chinense steppe and Stipa grandis steppe) and meadow steppe (Filifolium sibiricum steppe| S. baicalensis steppe and L. chinense steppe) at individual sites in Inner Mongolia| using the CENTURY ecosystem model. In the simulation of climate change| loss of soil organic C ranges from 783 gC.m(-2) in meadow steppe to 1485 gC.m(-2) in typical steppe| and annual above-ground net primary production (ANPP) decreases by 17.6 gC.m(-2) in meadow steppe to 29.5 gC.m(-2) in typical steppe under CCC (Canadian Climate Center). While under GFDL (Geophysical Fluid Dynamics Laboratory)| loss of soil organic C varies from 584 gC.m(-2) in typical steppe to 1164 gC.m(-2) in meadow steppe| and ANPP decreases in the range of 18.3 gC.m(-2) in typical steppe to 32.1 gC.m(-2) in meadow steppe. In the simulations of climate change plus elevated CO2 (from 350 p.p.m. to 700 p.p.m.)| ANPP decreases by 5.4 gC.m(-2) in meadow steppe to 11.3 gC.m(-2) in typical steppe under CCC + CO2| while ANPP varies from an increase of 1.8 gC.m(-2) in S. grrmdis steppe to a decrease of 20.6 gC.m(-2) in meadow steppe under GFDL + CO2. Losses of soil organic C are slightly lower (in the range of 42 gC.m(-2) to 248 gC.m(-2)) than losses of soil organic C under climate change only. These five steppe ecosystems are very sensitive to climate change| dependent upon projected change in temperature and precipitation by GCMs of CCC and GFDL. 4295,1995,4,3,Sensitivity of transient eddies to climate change in the CCC general circulation model,We use eddy life-cycle simulations to evaluate the response of atmospheric transient eddies to a global warming caused by CO2 doubling in the CCC general circulation model. In simulations using Northern Hemisphere winter conditions| transient waves attain larger kinetic energy and encompass a wider range of latitudes in the warmer climate. This behaviour contrasts with a previous investigation that used output from the NCAR and GFDL models. Our analysis indicates two primary factors for the difference between model responses: (1) a smaller change in the mid-latitude temperature gradient in the CCC model| which allows (2) increased atmospheric water vapour in mid-latitudes to catalyze a more rapidly evolving life-cycle. 4312,1995,2,3,SENSITIVITY TO PRESCRIBED CHANGES IN SEA-SURFACE TEMPERATURE AND SEA-ICE IN DOUBLED CARBON-DIOXIDE EXPERIMENTS,Time sclice experiments are performed with the atmospheric GCM ARPEGE| developed at Meteo-France| to study the impact to increases in the atmospheric carbon dioxide. This spectral model runs at T42 horizontal resolution with 30 vertical layers including a comprehensive tropospheric and stratospheric resolution and a prognostic parameterization of the ozone mixing ratio. The model is forced in a 5-year control run by climatological SSTs and sea-ice extents in order to obtain an accurate simulation of the present-day climate. Two perturbed runs are performed using SSTs and sea-ice extents for doubled CO2 concentration| obtained from transient runs performed by two coupled atmospheric-oceanic models run at the Max Planck Institute (MPI) in Hamburg and the Hadley Centre (HC). A global surface temperature warming of 1.6 K is obtained with the MPI SST anomalies and 1.9 K with the HC SST anomalies. The precipitation rate increases by 4.2% (and 4.7%). The features obtained in the stratosphere (a cooling increasing with the altitude and an increase in the ozone mixing ratio) are not sensitive to the oceanic forcing. On the contrary| the ano malies in the troposphere such as a warming increasing with altitude| an acceleration of westerly jets and a raised cloud height| depend on the oceanic forcing imposed in the two perturbed runs. Special attention is given to continental areas where the impact of the oceanic forcing is studied over eight regions around the globe. Regions sensitive to oceanic forcing such as Europe are identified in contrast with areas where the patterns are driven by land-surface physical processes| such as over continental Asia. Finally| the Koppen classification is applied to the climate simulated in the three experiments. Both doubled CO2 runs show the same predominance of global warming over precipitation changes in the Koppen analyses. 4374,1995,2,4,SEVERE CONVECTIVE WEATHER IN THE CONTEXT OF A NIGHTTIME GLOBAL WARMING,The recent finding that most of the global warming observed these past decades is due to an increase of the nighttime temperature may have important implications on severe storms occurrence. Indeed| the daily minimum temperature which is generally recorded in the early morning is an approximation of the wet bulb potential temperature observed during the following afternoon| which is a storm predictor. A mean minimum temperature increase in a region will then probably be accompanied by an increase in thee storm frequency. This hypothesis is tested in France for the years 1946 to 1992 with the annual mean minimum temperature in summer being compared to a yearly hail severity index deduced from hail insurance data. The two elements are found to be year-to-year correlated| and the correlation gives a 40% increase in the hail damage for a 1 degrees C increase in the mean minimum temperature. 4322,1995,2,3,SIMPLE CARBON ASSIMILATION RESPONSE FUNCTIONS FROM ATMOSPHERIC CO2| AND DAILY TEMPERATURE AND SHORTWAVE RADIATION,A global 'CO2 fertilizer effect' multiplier is often used in crop or ecosystem models because of its simplicity. However| this approach does not take into account the interaction between CO2| temperature and light on assimilation. This omission can lead to significant under- or overestimation of the magnitude of beneficial effects from elevated CO2| depending on environmental conditions. We use a mechanistic model of the biochemistry of photosynthesis to represent the response of net assimilation to different levels of CO2| temperature and radiation| on the daily time scale. Instantaneous assimilation rates for an idealized canopy model are integrated through diurnal cycles of environmental variables derived from historical climate data at three locations in North America. The calculated CO2 fertilizer effect is greatest at high light and warm temperatures. The results are summarized by assimilation response surfaces specified by the CO2 concentration| the canopy leaf area index| and by daily values of temperature and radiation available from climatic records. These summary functions are suitable for incorporation into crop or ecosystem models for predicting carbon assimilation or biomass production on a daily time step. An example application of the function reveals that for a relatively cool| high latitude location| the beneficial effects from a CO2 doubling would be negligible during the early spring| even assuming a + 4 degrees C global warming scenario. In contrast| the beneficial effects from increasing CO2 at a relatively warm| lower latitude location are greatest in the spring| but decline in late summer because of excessively warm temperatures with a + 4 degrees C global warming. 2566,1995,2,4,Simulation studies on risk analysis of rice leaf blast epidemics associated with global climate change in several Asian countries,The combination model (coupling of CERERS-RICE and BLASTSIM) was used to study the effects of global climate change on rice leaf blast epidemics in several Asian countries by simulations. Historical daily weather data were collected from fifty-three locations in five Asian countries. Two weather generators| WGEN and WMAK| from the Decision Support System for Agrotechnology Transfer (DSSAT) were utilized to produce estimated daily weather data for each location. Effects of global climate change in terms of temperature change and enhanced UV-B (ultraviolet-B) on blast epidemics were simulated. Thirty years of daily weather data produced by one of the two generators for each of fifty-three locations in five Asian rice-growing countries were used for driving the combination model to simulate blast epidemics under each condition of global climate change. Maximum blast severity| the distribution of area under disease progress curve (AUDPC) and estimated yield losses caused by leaf blast resulting from 30 years of simulation were analysed statistically. In most locations| temperature changes had significant effects on disease development. However| these effects varied between different agroecological zones. In cool subtropical zones such as Japan and northern China| elevation of ambient temperature resulted in a higher risk of blast epidemics. Situations in the humid tropics and warm humid subtropics were opposite to those in cool areas. A lower temperature resulted in greater risk of blast epidemics. Higher AUDPC did not always cause more yield losses. The same AUDPCs did not cause the same yield losses during different growing seasons under different weather conditions. The yield loss caused by enhanced UV-B was normally at 9-10%| independent of temperature change| and the deviation was much smaller than that caused by blast. Enhanced UV-B would cause much more severe blast when the temperature changes to cooler than normal| especially in tropical countries. 4320,1995,2,4,SIMULTANEOUS EFFECTS OF NIGHTTIME TEMPERATURE AND AN ALLELOCHEMICAL ON PERFORMANCE OF AN INSECT HERBIVORE,One effect of global warming may be an increase in night-time temperatures with daytime temperatures remaining largely unchanged. We examined this potential effect of global warming on the performance of tobacco hornworm larvae| Manduca sexta (Sphingidae)| by manipulating night-time temperature and dietary rutin levels simultaneously under a 12 light:12 dark photoregime. All four thermal regimes (26:14| 26:18| 26:22| and 26:26 degrees C) had a daytime temperature of 26 degrees C| with the night-time temperature increased from 14 to 26 degrees C by increments of 4 degrees C. Dietary rutin levels (0| 10 and 20 mu-moles g(-1) fresh weight of diet) reflected those occurring naturally in the leaves of tomato| a preferred host plant of M. sexta. With low night-time temperatures (14 and 18 degrees C)| rutin had a negative linear effect on developmental rate| relative growth rate and relative consumption rate of the caterpillars. However| at a night-time temperature of 22 degrees C| rutin had a negative non-linear effect. At a night-time temperature of 26 degrees C| rutin had a negative linear impact but less so than at the other nighttime temperatures. Likewise| the negative effect of rutin on molting duration was mitigated as night-time temperature increased. Final larval weight decreased linearly with increased dietary rutin concentrations. Total amount of food ingested was not affected by either rutin or thermal regime. As expected| the caterpillars developed faster under an alternating 26:14 degrees C regime than a constant 20 degrees C regime (the average temperature for the alternating regime)| but the effect of rutin depended on the thermal regime. Switching daytime and night-time temperatures had no statistically significant effect on caterpillar performance. Overall| the effect of rutin on rates of larval performance was greater at some levels of warmer nights but damped at another level. These results indicate that the potential effect of warmer nights on insect performance is not a simple function of temperature because there can be interactions between night-time temperature and dietary allelochemicals. 4462,1995,3,4,SOLAR HYDROGEN ELECTRICITY-GENERATION IN THE CONTEXT OF GLOBAL CO-2 EMISSION REDUCTION,The relative costs and CO2 emission reduction benefits of advanced centralized fossil fuel electricity generation| hybrid photovoltaic-fossil fuel electricity generation| and total solar electricity generation with hydrogen storage are compared. Component costs appropriate to the year 2000-2010 time frame are assumed throughout. For low insolation conditions (160 W m(-2) mean annual solar radiation)| photovoltaic electricity could cost 5-13 cents/kWh by year 2000-2010| while for high insolation conditions (260 W m(-2)) the cost could be 4-9 cents/kWh. Advanced fossil fuel-based power generation should achieve efficiencies of 50% using coal and 55% using natural gas. Carbon dioxide emissions would be reduced by a factor of 2 to 3 compared to conventional coal-based electricity production in industrialized countries. In a solar-fossil fuel hybrid| some electricity would be supplied from solar energy whenever the sun is shining and remaining demand satisfied by fossil fuels. This increases total capital costs but saves on fuel costs. For low insolation conditions| the costs of electricity increases by 0-2 cents/kWh| while the cost of electricity decreases in many cases for high insolation conditions. Solar energy would provide 20% or 30% of electricity demand for the low and high insolation cases| respectively. In the solar-hydrogen energy system| some photovoltaic arrays would provide current electricity demand while others would be used to produce hydrogen electrolytically for storage and later use in fuel cells to generate electricity. Electricity costs from the solar-hydrogen system are 0.2-5.4 cents/kWh greater than from a natural gas power plant| and 1.0-4.5 cents/kWh greater than from coal plant for the cost and performance assumptions adopted here. The carbon tax required to make the solar-hydrogen system competitive with fossil fuels ranges from $70-660/tonne| depending on the cost and performance of system components and the future price of fossil fuels. Leakage of hydrogen from storage into the atmosphere| and the eventual transport of a portion of the leaked hydrogen to the stratosphere| would result in the formation of stratospheric water vapor. This could perturb stratospheric ozone amounts and contribute to global warming. Order-of-magnitude calculations indicate that| for a leakage rate of 0.5% yr(-1) of total hydrogen production which might be characteristic of underground hydrogen storage - the global warming effect of solar-hydrogen electricity generation is comparable to that of a natural gas-solar energy hybrid system after one year of emission| but is on the order of 1% the impact of the hybrid system at a 100 year time scale. Impacts on stratospheric ozone are likely to be minuscule. 2593,1995,3,3,STATE ROLES IN THE GLOBAL CLIMATE-CHANGE ISSUE,Events in 1988 helped focus the attention of several states on the global climate change issue. Consequently| the National Governors' Association conducted an assessment in 1989 and recommended various actions. By 1994| 22 states have enacted laws or regulations and/or established research programs addressing climate change. Most of these ''no regrets'' actions are set up to conserve energy or improve energy efficiency and also to reduce greenhouse gas emissions. Illinois has adopted an even broader program by 1) establishing a Global Climate Change Office to foster research and provide information and 2) forming a task force to address a wide array of issues including state input to federal policies such as the Clinton administration's 1993 Climate Change Action Plan and to the research dimensions of the U.S. Global Climate Change Research Program. The Illinois program calls for increased attention to studies of regional impacts| including integrated assessments| and to research addressing means to adapt to future climate change. These various state efforts to date help show the direction of policy development and should be useful to those grappling with these issues. 4411,1995,4,4,STATISTICS FOR ENVIRONMENTAL-CHANGE,Major changes to the global environment and their impact upon statistical requirements are presented. The need for extensive yet accurate datasets is stressed and the difficulties of achieving appropriate sampling strategies are described. Examples are presented of environmental studies in use in diverse field such as global warming| sustainability| agroforestry and intercropping| and local community studies. The history of the use of environmental statistics is highlighted as is the need for modern methods to handle large| multivariate datasets likely to be subject to both spatial and temporal variability. 4433,1995,5,3,SURFACE FIELD CONVECTION DURING CORDILLERAN EXTENSION AND THE GENERATION OF METAMORPHIC CO2 CONTRIBUTIONS TO CENOZOIC ATMOSPHERES,Modeling of hydrogeological regimes associated with crustal extension indicate that flux values for deeply convected meteoric water are on the order of 10(-3) m3 . m-2 . yr-1. Calculated CO2 fluxes produced by infiltration-driven| metamorphic decarbonation reactions along the circulation path are 2.4 x 10(-4) m3 . m-2 . yr-1 or 3.8 mol . m-2 . yr-1. Application of the model to Cenozoic extension in the North American Cordillera demonstrates that CO2 generated in this manner may have been a major contributor to elevated CO2 contents of Cenozoic atmospheres and the resulting global warming due to the CO2 greenhouse effect. 4329,1995,3,3,SUSTAINABLE DEVELOPMENT IN INDONESIA - A CASE-STUDY OF AN INDIGENOUS REGIME OF ENVIRONMENTAL-LAW AND POLICY,The tropical rainforests of Indonesia are threatened with deforestation caused by rapid economic development. Because this development hastens global warming and reduces biodiversity| it violates the doctrine of sustainable development. The Brundtland report| Our Common Future (Brundtland| 1987)| defined sustainable development as 'development that meets the needs of the present| without compromising the ability of future generations to meet their own needs'. Sustainable development was adopted as the overarching world development policy of the 21st century at the Earth Summit in 1992| which introduced international accords to integrate economic development and environmental protection| manage and conserve the world's forests| stabilize production of the gases that cause global warming| and conserve the variety of living species. Indonesia views sustainable development with suspicion and is committed to economic development on the Western model. Sustainable development advocates| however| seek to save the Indonesian rainforests because they amount to 10% of those remaining in the world. They fear that the destruction of Indonesia's rainforests will| by hastening global warming| burden future generations with such problems as coastal flooding| migration of agricultural regions and habitat loss and| by reducing biodiversity| deprive them of the opportunity to study species and use them to improve the human condition. The conservation of the tropical rainforests of Indonesia may depend on the rediscovery of its indigenous natural resource systems| which are tantamount to a regime of environmental law and policy. These systems include the water temple system of Ball| the home-garden system of Java| the adat and sasi systems of Nusa Tenggara and Maluku| the land-tenure system of West Kalimantan| the shifting cultivation system of East Kalimantan| and the traditional non-timber production systems of forest dwellers. These systems| which are characterized by permaculture| biodiversity conservation| property rights| and sustained yields| prevent Hardin's 'tragedy of the commons' (Hardin| 1968)| and foster Leopold's 'biotic integrity' (Leopold| 1968). As a paradigm of land use governance| such systems have sustained the economy and environment of Indonesia on behalf of its people for millennia. It is concluded that the indigenous natural resource systems of Indonesia have a vital role to play in its sustainable development.
4290,1995,2,3,Synoptic scale disturbances of the Indian summer monsoon as simulated in a high resolution climate model,The Hamburg atmospheric general circulation model ECHAM3 at T106 resolution (1.125 degrees lat./lon.) has considerable skill in reproducing the observed seasonal reversal of mean sea level pressure| the location of the summer heat low as well as the position of the monsoon trough over the Indian subcontinent. The present-day climate and its seasonal cycle are realistically simulated by the model over this region. The model simulates the structure| intensity| frequency| movement and lifetime of monsoon depressions remarkably well. The number of monsoon depressions/storms simulated by the model in a year ranged from 5 to 12 with an average frequency of 8.4 yr(-1)| not significantly different from the observed climatology. The model also simulates the interannual variability in the formation of depressions over the north Bay of Bengal during the summer monsoon season. In the warmer atmosphere under doubled CO2 conditions| the number of monsoon depressions/cyclonic storms forming in Indian seas in a year ranged from 5 to 11 with an average frequency of 7.6 yr(-1)| not significantly different from those inferred in the control run of the model. However| under doubled CO2 conditions| fewer depressions formed in the month of June. Neither the lowest central pressure nor the maximum windspeed changes appreciably in monsoon depressions identified under simulated enhanced greenhouse conditions. The analysis suggests there will be no significant changes in the number and intensity of monsoon depressions in a warmer atmosphere. 2574,1995,3,3,SYSTEM FOR COUNTERMEASURES OF CARBON-DIOXIDE,Mitigation measures to global climate change are classified focusing on carbon dioxide in order to cover all potential technologies. A templet is proposed to assess each technology and technological systems under the standardized criteria. 4358,1995,3,3,SYSTEM-ANALYSIS OF CO2 REMOVAL FROM THERMAL ELECTRIC-POWER PLANTS AND STORAGE IN DEEP-SEA,Thermal power plants located in Japan| burning coal| petroleum| LNG or methanol| were analyzed here from the viewpoint of the energy balance and the overall CO2 emission| including the emission from the fuel treatment stage such as the mining of fossil fuels| transportation| and the post-combustion stage such as CO2 removal and storage. The reduction of the net CO2 emission by CO2 removal and storage is the largest for the coal fired plant of others| but the decrease in the energy efficiency is also the largest. This result suggests that if there is not any problems for supplying coal| CO2 removal and storage should be equipped on the coal fired plants to mitigate the global warming. 4304,1995,4,4,Tackling air pollution: The role of the local highway authority,The paper describes how Lancashire County Council initially undertook. a 'Green Audit' in 1989 to determine the state of the environment in Lancashire and to provide a baseline for comparison purposes in the future. Following this comprehensive study| an Environmental Forum| comprising 80 organizations| was established. This was responsible for producing an Environmental Action Programme (EAP) in March 1993. The paper discusses the major measures relating to transport in the EAP and how they contribute to the relief of global warming| to reviving towns| to improving air quality| and to conserving wild life and the countryside. These measures are also linked to the sustainability objectives as put forward by the Earth Summit Conference in Rio de Janeiro in 1992| and subsequently by those of the European Union and the UK. Government. The paper relates the EAP measures| issued jointly by the Department of the Environment and the Department of Transport. Planning Policy Guidance on Transport (PPG13). It discusses the recommendations of recent transport studies undertaken in the major urban areas of Lancashire and the way measures to promote more sustainable transport policies have been translated into package bids for TPP purposes| The paper proceeds to describe a vehicle emissions model for assessing the effects of road improvements or traffic management measures on air pollution| and concludes with a discussion on aspects of the Royal Commission on Environmental Pollution's 18th Report on Transport and the Environment. 4405,1995,3,3,TECHNICAL PROGRESS AND CLIMATIC-CHANGE,The global warming debate has neglected and thus underestimated the importance of technical change in considering reduction in greenhouse gases and adaptation to climate change| Relevant quantitative cases of long-run technical change during the past 100 years are presented in computing| communications| transport| energy| and agriculture| A noteworthy technological trajectory is that of decarbonization| or decreasing carbon intensity of primary energy| If human societies have not yet reached the end of the history of technology| the cost structure for mitigation and adaptation changes could be cheap. 4436,1995,2,4,TEMPERATURE AND LAKE-OUTLET COMMUNITIES,1. Lake outlets are formed where streams become impounded by natural processes| or as the result of human activities. Water can drain from the surface of the lake| or from lower in the water column and the physico-chemical| and biotic| characteristics of these two types of lake outlets are very different during lake stratification. 2. Temperature will have effects on the lake water and on the lake-outlet community. The effect of temperature on the surface waters of the lake will be of special importance since this is the region where the influence of solar radiation is at its highest. Warming of the surface waters of lakes will have many direct| and indirect effects| on the lake-outlet communities. 3. Increasing temperature above levels currently found will have both advantages| and disadvantages for components of the lake-outlet communities. 4396,1995,4,4,TEMPERATURE EFFECTS OF PASSIVE GREENHOUSE APPARATUS IN HIGH-LATITUDE CLIMATE-CHANGE EXPERIMENTS,1. Passive greenhouse apparatus is commonly used to investigate the in situ biological response of terrestrial communities to global warming. 2. Although close conformity of greenhouse treatment effects to general circulation model (GCM) scenarios is widely claimed| no proof of such a relationship has yet been published. 3. Here| the relationship between passive greenhouse thermal environment and future climate conditions is considered using temperature data collected from within and without greenhouses deployed in the maritime Antarctic. It is revealed that in terms of thermal extremes| diel and annual variation| and overall distribution across the temperature spectrum| such apparatus achieves only poor simulation of GCM forecasts. 4. During summer| greenhouses induce an amplified daily range of temperatures| elevated maxima and accelerated rates of change. 5. During spring and autumn| diel temperature variation continues inside the greenhouses while snow cover protects the controls. 6. During winter| an inverse treatment effect occurs| in which the relative depth of snow cover causes lower temperatures in greenhouses than in controls. 7. These treatment effects differ significantly from GCM climate predictions. Changes recorded in the composition| structure and function of greenhouse biota may thus be artefacts of the methodology. 8. Thorough a priori testing of greenhouse treatment effects is recommended for future climate change studies that are to be conducted in environments subject to seasonal snowfall| solar elevation and day length. 2602,1995,2,4,TEMPERATURE EFFECTS ON KINETICS OF MICROBIAL RESPIRATION AND NET NITROGEN AND SULFUR MINERALIZATION,Global climate change may impact the cycling of C| N| and S in forest ecosystems because increased soil temperatures could alter rates of microbially mediated processes. We studied the effects of temperature on microbial respiration and net N and S mineralization in surface soils from four northern hardwood forests in the Great Lakes region. Soil samples were incubated in the laboratory at five temperatures (5| 10| 15| 20| and 25 degrees C) for 32 wk. Headspace gas was analyzed for CO2-C at 2-wk intervals| and soils were extracted to determine inorganic N and S. Cumulative respired C and mineralized N and S increased with temperature at all sites and were strongly related (r(2) = 0.67 to 0.90| significant at P = 0.001) to an interaction between temperature and soil organic C. Production of respired C and mineralized N was closely fit by first-order kinetic models (r(2) greater than or equal to 0.94| P = 0.001)| whereas mineralized S was best described by zero-order kinetics. Contrary to common assumptions| rate constants estimated from the first-order models were not consistently related to temperature| but apparent pool sizes of C and N were highly temperature dependent. Temperature effects on microbial respiration could not be accurately predicted using temperature-adjusted rate constants combined with a constant pool size of labile C. Results suggest that rates of microbial respiration and the mineralization of N and S may be related to a temperature-dependent constraint on microbial access to substrate pools. Simulation models should rely on a thorough understanding of the biological basis underlying microbially mediated C| N| and S transformations in soil. 4326,1995,4,3,TEMPERATURE-GRADIENT CHAMBERS FOR RESEARCH ON GLOBAL ENVIRONMENT CHANGE .3. A SYSTEM DESIGNED FOR RICE IN KYOTO| JAPAN,Synthesis and validation of crop models for assessment of of the impact of elevated atmospheric CO2 concentration and anticipated global warming on crop production require crop response data obtained under field-like conditions| The temperature gradient chamber (TGC) with the facility for CO2 enrichment allows the creation of various CO2 and temperature regimes for crops over the entire growth period with relatively inexpensive construction and running costs| The TGC develops a temperature gradient along its longitudinal axis using solar energy during the day and heating at night while maintaining the natural diurnal cycle| The temperature gradient and the CO2 concentration in the TGC are regulated by computer control of the air ventilation rate through the TGC and of the CO2 release rate| Longitudinal gradients of CO2 concentration and water vapour pressure deficit of air in the TGC were generally less than 5% and +/-0.2 kPa| respectively. A CO2 enrichment experiment on rice in the TGC showed that a doubling of the CO2 concentration markedly enhanced crop dry matter production| Temperature had less effect on dry matter production| although panicle dry weight was greatly decreased at higher temperature as a result of high-temperature-induced sterility of rice spikelets| Since rice spikelets are most sensitive to high temperature at the moment of flowering| and their flowering habit is highly synchronized with the diurnal courses of environmental conditions| the TGC is a useful tool in understanding rice responses to changes in atmosphere and temperature. 2607,1995,4,4,The ANTARES AMS centre: A status report,The ANTARES accelerator mass spectrometry facility at Lucas Heights Research Laboratory is operational and AMS measurements of C-14| Al-26 and Cl-36 are being carried out routinely. Measurement of I-129 recently commenced and capabilities for other long-lived radioisotopes such as Be-10 are being established. The overall aim of the facility is to develop advanced programs in Quaternary science| global climate change| biomedicine and nuclear safeguards. 4421,1995,2,3,The arctic flux study: A regional view of trace gas release,Fluxes of trace gases from northern ecosystems represent a highly uncertain and potentially significant component of the arctic land-atmosphere system| especially in the context of greenhouse-induced climate change. The initial goal of the Arctic Flux Study (a part of NSF's Arctic System Science Program) is a regional estimate of the present and future movement of materials between the land| atmosphere and ocean in the Kuparuk River basin in northern Alaska. We are measuring rates and controls of processes along a north-south transect running from the marshy coastal plain to mountain valleys. Important vertical fluxes under study are the release of CO2 and CH4 from soils and water| lateral fluxes are surface water| nutrients| and organic matter. A hierarchy of measurements allow the rates and understanding of processes to be scaled from plots to the landscape| regional| and circumarctic level. These include gas flux measurements in small chambers| measurements over larger areas by eddy correlation from small towers| and measurements at the landscape scale from airplane overflights. Experimental manipulations of carbon dioxide| soil moisture| nutrients and soil temperature from this and other studies give information on process controls. The distribution of plant communities has been described at several landscape-scale sites and a hierarchic GIS has been developed for the region at three scales (plot| landscape| region). Climate is measured at six sites and hydrological processes are being studied at each watershed scale. In the soils| measurements are being made of soil organic matter and active layer thickness and of availability of soil organic matter for microbial transformation into CO2 and CH4. Fluxes and process understanding have been incorporated into a hierarchy of models at different scales. These include models of regional climate nested in a GCM; of regional- and continental-scale plant productivity and carbon cycling including CO2 release under altered climates; watershed and regional models of hydrology; and surface energy budgets. After the first year of study the regional climate model has been successfully configured to the northern Alaska region We have also measured a large release of carbon dioxide from tundra soils in all but the coldest and wettest parts of the transect. The rates from eddy correlation towers (landscape level) agree closely with rates from chambers (plot level). Observations| experimental manipulations and modelling analyses result in the prediction that the combination of warmer and drier soils is responsible for the large CO2 release. 4300,1995,2,4,The boreal forests of north-eastern Eurasia,The distribution| diversity and structure of boreal forests of monsoon Asia are reviewed. The boreal zone is circumscribed by the isotherms of 15 degrees C and 45 degrees C of Kira's Warmth Index (WI) and includes the territory of the Amur basin| the seashores of the Sea of Okhotsk| Kamchatka| Sakhalin and the Kuril islands. Boreal forests also occur on the mountains of Hokkaido| Honshu| Korea and NE China. The oceanic sectors of the boreal zone are composed mainly of birch forests| the marine sectors of spruce-fir forests and the continental sectors of larch and pine forests. The upper limit of the boreal forests ascends from the lowest level in the North to ca. 1500 m a.s.l. in the South of the zone| and reaches above 2500 m in the mountains of the temperate zone. In the boreal zone the secondary forests are common. They form after fires and cutting. Volcanism is an essential factor in the forest dynamics in the oceanic part of the region. It is suggested that as a result of global warming one may expect a strong alteration in vegetation pattern| especially in the northern and mountain areas. 4314,1995,3,4,THE COMPARATIVE AIR EMISSIONS OF DIESEL-FUELED AND COMPRESSED-NATURAL-GAS-FUELED BUSES IN VENEZUELA - A CASE-STUDY EMPLOYING A FUEL CHAIN APPROACH,Energy services| such as one hour of lighting| or one passenger kilometer of transportation depend upon significant chains of preceding activities in the energy sector. The stages in a fuel chain| for example crude oil recovery| oil refining| or fuel distribution often have significant environmental impacts. Fuel chain analysis is a means of accurately comparing the environmental impacts of alternative energy policy| planning| and investment decisions. A fuel chain analysis was used to compare air emissions from diesel- and compressed-natural-gas- (CNG) fueled buses in Caracas. Because of methane emissions from the existing natural gas recovery and transmission systems in Venezuela| and the lower efficiency of heavy-duty compressed natural gas vehicles in comparison to diesel vehicles| the campressed natural gas fuel chain is not clearly a good choice from the perspective of global warming potential (GWP). However| emissions of local air pollutants| such as particulates| carbon monoxide| and nitrogen oxides| were significantly lower for the CNG fuel chain. The results suggests that a CNG vehicle program may only achieve significant greenhouse gas emission reductions if it can be associated (either directly or indirectly) with decreases in flaring| venting| and other fugitive emissions fi om the natural gas system| or if the efficiency of heavy duty CNG engines improves in comparison to diesel engines. The fuel chain approach has also been applied to an analysis of electricity generating options in Venezuela| and it may be applicable to other sectors and countries conducting greenhouse gas mitigation analyses. 4439,1995,2,4,THE CONSEQUENCES OF GLOBAL WARMING FOR STREAM INVERTEBRATES - A FIELD SIMULATION,1. We manipulated the thermal regime of a stream and analyzed the population genetics of constituent species to examine the effects of global warming on stream invertebrates. 2. Increased temperature resulted in significantly lower total densities of invertebrates and altered growth patterns for two target species. 3. Hyalella azteca showed the greatest change in growth and also exhibited high levels of genetic differentiation among populations. Nemoura trispinosa showed only small shifts in growth and phenology and exhibited little genetic differentiation among populations. 4. The potential impacts of global warming may depend critically on the dispersal abilities and genetic structure of lotic populations. 2597,1995,2,4,THE ECOLOGY OF MANGROVE CONSERVATION AND MANAGEMENT,Despite the recent better understanding and awareness of the role of mangroves| these coastal forest communities continue to be destroyed or degraded (or euphemistically reclaimed) at an alarming rate. The figure of 1% per year given by Ong (1982) for Malaysia can be taken as a conservative estimate of destruction of mangroves in the Asia-Pacific region. Whilst the Japanese-based mangrove wood-chips industry continues in its destructive path through the larger mangrove ecosystems of the region| the focus of mangrove destruction has shifted to the conversion of mangrove areas into aquaculture ponds and the consequences of the unprecedented massive addition of carbon dioxide to the atmosphere by post industrial man. Mangroves are non-homogeneous; characterised by distinct vegetative zones that occupy the interface between land and sea and dynamically interacting with the atmosphere above as well as with the influences of the adjacent land and sea. The conservation of mangroves should thus include not only the various vegetation and tidal inundation zones but also the adjacent marine and terrestrial areas (including the water catchment area). On the current concern with global climate change| it is pointed out that relative sea level change is very much site dependent. For effective planning and management| it is vital to know if a particular site is stable| rising or sinking so efforts should be directed to find suitable methods for determining this. However| should rapid relative sea level rise take place| there is very little likelihood of saving mangroves whose landward margins have been developed by man| a fact to bear in mind when selecting sites for conservation. The Matang mangroves of Malaysia is a rare case of successful sustainable management of a tropical rain forest. Although the tools of management are available they are not widely applied. We particularly urge the Japanese mangrove wood-chips industry to look to long term sustainable use rather than short term gains. A suggestion is made to appeal to the new Government of Japan to take the lead in environmental friendliness especially to the rain forests of the Asia-Pacific region. 4403,1995,3,4,THE ECONOMICS OF STABILIZING ATMOSPHERIC CO2 CONCENTRATIONS,This paper examines the economics of stabilizing atmospheric CO2 concentrations| A particular concentrations target can be achieved in a variety of ways| It turns out that the choice of emissions time-path is as important as the concentrations level itself in determining the ultimate price-tag| Rather than choosing arbitrary emission trajectories| more attention needs to be devoted to identifying those paths that minimize the costs of achieving a specific target. 4310,1995,2,4,THE EFFECT OF CLOUDS AND WIND ON THE DIFFERENCE IN NOCTURNAL COOLING RATES BETWEEN URBAN AND RURAL-AREAS,The urban warming effect is interesting in its own right and is important for understanding global warming. The aim of this study is to determine how the urban warming effect changes with cloud conditions and with wind speed. Studies of the urban warming effect have mostly concentrated on the urban-rural difference in daily maximum or minimum temperatures. The problem was approached using a new technique. Instead of comparing a city| represented by a first-order weather station| with the surrounding rural area| represented by data collected by cooperative observers; pairs of cities| each with a first-order weather station| were studied. One city was large. The other city was small enough to have a minimal warming effect and was close enough to the larger city to approximately represent the rural area. In this way| hourly temperatures| cloud cover| and wind data could be studied rather than only the differences between the daily maxima or minima. Results show that wind disrupts the normal nocturnal cooling pattern in which the smaller city| with lower thermal inertia| cools more quickly than the larger city. Clouds also disrupt this pattern| at least to the extent that one must be careful about extrapolating either magnitudes or patterns of urban-rural temperature difference observed by satellites under clear sky conditions to partly cloudy or cloudy conditions. 4353,1995,2,4,THE EFFECTS OF ANTHROPOGENIC HABITAT DISTURBANCE| HABITAT DESTRUCTION| AND GLOBAL WARMING ON SHALLOW MARINE BENTHIC FORAMINIFERA,Protists such as benthic foraminifera are not immune to the effects of global warming or to shallow marine environmental degradation and destruction caused by the activities of humans. Increasing environmental stresses are likely to lead| in the near future| to disruption and dynamic restructuring of communities| localized extinctions of both rare and abundant species| and total extinction of rare species (and| perhaps| abundant species) in the shallow marine environment. Low latitude and/or developed coastal environments and communities are likely to experience the greatest changes. The role of benthic foraminifera in the trophic structure of shallow marine communities dictates that many other organisms will be affected by changes in the structure and diversity of shallow marine foraminiferal populations. 4464,1995,3,4,THE EXPECTED GREENHOUSE BENEFITS FROM DEVELOPING MAGMA POWER AT LONG VALLEY| CALIFORNIA,Magma power is the production of electricity from shallow magma bodies. Before magma becomes a practical source of power| many engineering problems must still be solved. When they are solved| the most likely site for the first magma power plant is Long Valley| California| USA. In this paper| we examine the greenhouse benefits from developing Long Valley. By generating magma power and by curtailing an equal amount of fossil power| we estimate the expected mass and the expected discounted value of reduced CO2 emissions. For both measures| the expected benefits seem to be substantial. 4363,1995,3,3,THE FULL FUEL-CYCLE OF CO2 CAPTURE AND DISPOSAL .3. AFFORESTATION| AND ENVIRONMENTAL IMPACTS,This paper reports on the assessment and valuation of the environmental impacts arising from the full fuel cycles of three fossil fuelled power plants equipped with CO2 capture and disposal facilities. The first of these is a Natural Gas Combined Cycle (NGCC) plant featuring CO2 separation and disposal to a disused gas well. The second is an Integrated Gasification Combined Cycle (IGCC) plant featuring CO2 separation and disposal to the deep ocean. The third case is a pulverised fuel plant with flue gas desulphurisation (PF+FGD) with CO2 capture by a managed forest at a site remote from the power plant. A wide variety of impacts have been assessed at local| regional and global scales. They include accidents affecting workers and the public| the effects of atmospheric emissions on health and buildings and the impacts of global warming. Issues associated with management of the forest designed to capture CO2 from the PF plant and assessment of the associated costs are also described. 4471,1995,3,4,THE FUTURE-ROLE OF NUCLEAR-POWER IN ADDRESSING GLOBAL ENVIRONMENTAL-PROBLEMS,Decision makers have to increasingly balance the costs versus benefits of various energy choices against a background of global environmental deterioration. This is particularly so in the choice of long term electricity production strategies where these have to be balanced against the potential of a very severe disruption of the world's climate due to global warming. In this presentation| the threat of global warming is quantified and scenarios are developed of future predicted energy consumption patterns and their impact on international policies to curb global warming| are analyzed. The conclusion is reached that the threat of global warming is so severe that| on the macro level| an international accepted strategy of utilising a proper balance between all forms of electricity production| is a matter of priority and that all national energy choices should be taken against this framework. Such strategic decisions on the macro level must| however| also translate into the micro level of energy production on topics which include: more efficient plant utilisation; more effective risk management; correct choice and application of technology; and better understanding of issues concerning safety| quality and environmental impact. 4338,1995,2,4,THE HUMAN BIOCLIMATES OF WESTERN AND SOUTH-PACIFIC ISLANDS AND CLIMATE-CHANGE,The current bioclimates of equatorial Western and tropical South Pacific have been assessed| using the concepts of effective temperature and relative strain as a basis for evaluating likely changes in human comfort regimes as a consequence of global warming. Current bioclimates may be considered marginally stressful for indigenous populations. Global warming will result in changes in the frequency| duration and intensity of physioclimatically stressful conditions. 4372,1995,2,4,THE IMPACT OF CLIMATE-CHANGE ON MARITIME LOCAL-AUTHORITIES - DRAINAGE ASPECTS,The subject of this paper is part of a wider investigation into the engineering implications of the predicted sea-level rise as a result of climate change on a typical maritime local authority (MLA) using the Borough of Gosport in Hampshire as a detailed case study. The paper describes the analysis of the drainage systems of three catchment areas| each with different surface characteristics| within the Borough of Gosport. The performance of each system is examined under a combination of three possible sea-level rise scenarios and two possible storm conditions. The results give cause for concern and have to be taken seriously; it is proposed that effects of rising sea levels| due to global warming| should be taken into account in current design work. It is proposed that a new assessment procedure 'climatic impact assessment' becomes a compulsory requirement for all schemes that might be sensitive to the effects of climate change. Many professional engineers still do not consider that global warming effects will take place. However| this paper confirms that the concerns being expressed regarding the effects of climate change have to be taken seriously. It is likely that every MLA will be affected by these changes| and the cost implications of this are very significant. There is a serious lack of systematic data collection for assessment of the possible impacts. 2559,1995,2,2,THE IMPACT OF CLIMATE-CHANGE ON THE RIVER RHINE - A SCENARIO STUDY,This paper concerns the impact of human-induced global climate change on the River Rhine discharge. For this purpose a model for climate assessment| named ESCAPE| is coupled to a water balance model| named RHINEFLOW. From climate scenarios| changes in regional annual water availability and seasonal discharge in the River Rhine Basin are estimated. The climate scenarios are based on greenhouse gases emissions scenarios. An assessment is made for ''best guess'' seasonal discharge changes and for changes in frequencies of low and high discharges in the downstream reaches of the river. In addition| a quantitative estimation of the uncertainties associated with this guess is arrived at. The results show that the extent and range of uncertainty is large with respect to the ''best guess'' changes. The uncertainty range is 2-3 times larger for the Business-as-Usual than for the Accelerated Policies scenarios. This large range stems from the doubtful precipitation simulations from the present General Circulation Models. This scenario study showed the precipitation scenarios to be the key-elements within the present range of reliable climate change scenarios. For the River Rhine ''best guess'' changes for annual water availability are small according to both scenarios. The river changes from a present combined snow-melt-rain fed river to an almost entirely rain fed river. The difference between present-day large average discharge in winter and the small average discharge in autumn should increase for all scenarios. This trend is largest in the Alpine part of the basin. Here| winter discharges should increase even for scenarios forecasting annual precipitation decreases. Summer discharge should decrease. ''Best guess'' scenarios should lead to increased frequencies of both low and high flow events in the downstream (Dutch) part of the river. The results indicate changes could be larger than presently assumed in ''worst case scenarios'' used by the Dutch water management authorities. 4459,1995,2,4,THE IMPACT OF GLOBAL WARMING ON LOCAL INCOMES FROM RANGE LIVESTOCK SYSTEMS,Using standard census data| an index is developed expressing the contribution of range livestock systems to total county incomes. This index is then applied to results of a simulation of the effects of global warming on the productivity of cow-calf range livestock systems in the western USA. Estimates of declining range-based incomes in a southern tier of states coupled with increasing productivity in the middle and northern Great Plains| the inter-mountain Rockies and the Pacific Northwest suggest that significant shifts could occur in the location of feeder calf production if these climate changes occur. 2551,1995,2,4,THE INFLUENCE OF ELEVATED CO2 ON COMMUNITY STRUCTURE| BIOMASS AND CARBON BALANCE OF MEDITERRANEAN OLD-FIELD MICROCOSMS,We studied the effects of a doubling of atmospheric CO2 concentration on intact monoliths of Mediterranean grassland in growth chambers where climatic field conditions were simulated. During the six month growing season| changes in community structure were monitored by quantifying species richness and cover. The CO2 exchange of microcosms was measured continuously and the resulting quantity and quality of biomass were evaluated. Species richness and cover did not respond to elevated C02. After one month of treatment| CO2 exchange measured during the day did not differ between CO2 levels but the night respiration was two-fold higher under elevated CO2. Stimulations of both day and night CO2 flux by short-term CO2 enrichment were recorded several times during the growing season. These results suggest that despite some downward adjustment of photosynthesis| net canopy photosynthesis was stimulated by elevated CO2| but this stimulation was compensated for by an increased respiration. The 20% stimulation of final phytomass under elevated CO2 was not significant: it resulted from unchanged live plant matter but a significant| 100% increase in litter accumulation. These results suggest that in low-productivity Mediterranean herbaceous systems| the greatest effect of CO2 is not on the storage of carbon in biomass but on the turnover of the carbon in the plants. 4435,1995,2,4,THE INFLUENCE OF RISING BACKGROUND TEMPERATURE ON THE EFFECTS OF MARINE THERMAL EFFLUENTS,1. Discharged effluent waters from directly cooled power stations in temperate zones are some 8-12 degrees C warmer than intake temperatures. 2. The direct effects of thermal discharges on marine organisms fall into four categories| the mean temperature in relation to ''normal''| the absolute temperature (as it may approach lethal levels)| short-term fluctuations in temperature and potential barriers to fish migration. These conditions tend to favour eurythermal species| notably those from the littoral or warmer zoogeography| while inhibiting stenotherms or cooler-water species. 3. A potential increase in background temperature would exacerbate the effects of mean and absolute temperature| although operating on a ''previously selected'' local community. While a natural temperature rise of 1 degrees C above normal can have a marked impact on even littoral species| any effluent temperature effects will be localized within a small area. 4416,1995,2,3,THE POLE OF SEA-ICE IN 2X CO2 CLIMATE MODEL SENSITIVITY .1. THE TOTAL INFLUENCE OF SEA-ICE THICKNESS AND EXTENT,As a first step in investigating the effects of sea ice changes on the climate sensitivity to doubled atmospheric CO2| the authors use a standard simple sea ice model while varying the sea ice distributions and thicknesses in the control run. Thinner ice amplifies the atmospheric temperature sensitivity in these experiments by about 15% (to a warming of 4.8 degrees C)| because it is easier for the thinner ice to be removed as the climate warms. Thus| its impact on sensitivity is similar to that of greater sea ice extent in the control run| which provides more opportunity for sea ice reduction. An experiment with sea ice not allowed to change between the control and doubled CO2 simulations illustrates that the total effect of sea ice on surface air temperature changes| including cloud cover and water vapor feedbacks that arise in response to sea ice variations| amounts to 37% of the temperature sensitivity to the CO2 doubling| accounting for 1.56 degrees C of the 4.17 degrees C global warming. This is about four times larger than the sea ice impact when no feedbacks are allowed. The different experiments produce a range of results for southern high latitudes with the hydrologic budget over Antarctica implying sea level increases of varying magnitude or no change. These results highlight the importance of properly constraining the sea ice response to climate perturbations| necessitating the use of more realistic sea ice and ocean models. 4417,1995,2,4,THE POTENTIAL EFFECTS OF CLIMATE-CHANGE ON WINTER MORTALITY IN ENGLAND AND WALES,In Britain death rates from several important causes| particularly circulatory and respiratory diseases| rise markedly during the colder winter months. This close association between temperature and mortality suggests that climate change as a result of global warming may lead to a future reduction in excess winter deaths. This paper gives a brief introductory review of the literature on the links between cold conditions and health| and statistical models are subsequently developed of the associations between temperature and monthly mortality rates for the years 1968 to 1988 for England and Wales. Other factors| particularly the occurrence of influenza epidemics| are also taken into account. Highly significant negative associations were found between temperature and death rates from all causes and from chronic bronchitis| pneumonia| ischaemic heart disease and cerebrovascular disease. The statistical models developed from this analysis were used to compare death rates for current conditions with those that might be expected to occur in a future warmer climate. The results indicate that the higher temperatures predicted for 2050 might result in nearly 9000 fewer winter deaths each year with the largest contribution being from mortality from ischaemic heart disease. However| these preliminary estimates might change when further research is able to make into account a number of additional factors affecting the relationship between mortality and climate. 4469,1995,2,4,THE POTENTIAL IMPACT OF GLOBAL WARMING ON SUMMER/AUTUMN CAULIFLOWER GROWTH IN THE UK,Separate established models of juvenility| vernalization and curd growth in cauliflower were used to estimate the duration of each growth phase in a sequence of crops of cv. White Fox for the years 1982-1992 inclusive. The models were then used to simulate what might happen to the same sequence of crops following potential rises in mean temperature of 0.3| 0.6| 0.9| 1.2| 1.5 and 3.0 degrees C associated with global warming. For early-emerging crops temperature rise greatly reduced the length of the juvenile and curd growth phases but had little effect on vernalization and consequently reduced the overall duration of growth. Later in the season temperature rise reduced the lengths of the juvenile and curd growth phases but increased the duration of vernalization because temperatures were beyond its optimum. The effect of this was such that in a few crops the overall duration of crop growth was increased. Increased temperatures were shown to increase significantly the variability of duration of vernalization while significantly reducing the variability of duration of curd growth. There were no significant effects on the variability of juvenility or the overall growth period. 2543,1995,4,4,THE QUALITY-CONTROL OF LONG-TERM CLIMATOLOGICAL DATA USING OBJECTIVE DATA-ANALYSIS,One of the major concerns with detecting global climate change is the quality of the data. Climate data are extremely sensitive to errant values and outliers. Prior to analysis of these time series| it is important to remove outliers in a methodical manner. This study provides statistically derived bounds for the uncertainty associated with surface temperature and precipitation measurements and yields a baseline dataset for validation of climate models as well as for a variety of other climatological uses. A two-step procedure using objective analysis was used to identify outliers. The first step was a temporal check that determines if a particular monthly value is consistent with other monthly values for the same station. The second step utilizes six different spatial interpolation techniques to estimate each monthly time series. Each of the methods is ranked according to its respective correlation coefficients with the actual time series| and the technique with the highest correlation coefficient is chosen as the best estimator. For both temperature and precipitation| a multiple regression scheme was found to be the best estimator for the majority of records. Results from the two steps are merged| and a combined set of quality control flags are generated. 4357,1995,3,3,THE ROLE OF CO2 REMOVAL AND DISPOSAL,This paper aims at examining the role of CO2 removal and disposal among various measures for CO2 abatement. The first part deals with the need of CO2 removal and disposal in the strategy toward stabilization of the air concentration of CO2. A macroscopic survey of CO2 emission in developed world indicates that reduction of CO2 emission will be a hard task as long as we employ only conventional measures and therefore implementation of innovative measures is indispensable for mankind to mitigate global warming substantially. The results of a model study on CO2 stabilization indicates that CO2 removal from flue gas and storage in some niches of the earth will play an important role within several tens years. The second part deals with the issue of CO2 ocean disposal| with referring to a controversy on its effectiveness in mitigating global warming and concludes that it is effective but needs more study both on science of CO2 behavior in the ocean and characteristics of damage function of global warming. Lastly the paper discusses the global strategy for CO2 abatement| taking into full account different stances of countries in the world and stresses the importance of concerted efforts of developed countries for RandD on CO2 removal and disposal technologies. 2608,1995,5,4,THE SUNDA AND SAHUL CONTINENTAL PLATFORM - LOST LAND OF THE LAST GLACIAL CONTINENT IN SE ASIA,Global climate change is the most significant phenomenon that may control the global variations of sea level over the coming thousands of years. During the alternate glacial and interglacial periods| ice-cap melting and ice accumulation in the high latitudes change the ocean water volume| which causes the sea level oscillations. For the longer periods| the change of sea level is due to the change of the basin volume following basin uplift or subsidence and the tectonic opening of the ocean floor due to plate motion. Some maximum glacial periods were marked by the very low sea level| about 125 m below the present sea level during the last glacial maximum| drying up and exposing the continental platform that was quickly covered by humid lowland tropical forest. The following rapid sea level rise due to the melting of the ice cap submerged the continent| transferring most of the carbon to the atmosphere. During the very low sea level| the deep pass Indian-Pacific Ocean Gateways remained open| allowing the global ocean current to go through the corridor between the two exposed platforms| Sunda in the West and Sahul in the East of the Indonesian Archipelago. Data obtained from these platforms will be important in order to understand the global climatic pattern from the Last Glacial Maximum (L.G.M. 18|000 BP) which was followed by a rapid sea level rise. 4366,1995,4,4,THE TEMPERATURE-DEPENDENCE OF SOIL ORGANIC-MATTER DECOMPOSITION| AND THE EFFECT OF GLOBAL WARMING ON SOIL ORGANIC-C STORAGE,One of the key questions in climate change research relates to the future dynamics of the large amount of C that is currently stored in soil organic matter. Will the amount of C in this pool increase or decrease with global warming? The future trend in amounts of soil organic C will depend on the relative temperature sensitivities of net primary productivity and soil organic matter decomposition rate. Equations for the temperature dependence of net primary productivity have been widely used| but the temperature dependence of decomposition rate is less clear. The literature was surveyed to obtain the temperature dependencies of soil respiration and N dynamics reported in different studies. Only laboratory-based measurements were used to avoid confounding effects with differences in litter input rates| litter quality| soil moisture or other environmental factors. A considerable range of values has been reported| with the greatest relative sensitivity of decomposition processes to temperature having been observed at low temperatures. A relationship fitted to the literature data indicated that the rate of decomposition increases with temperature at 0 degrees C with a Q(10) of almost 8. The temperature sensitivity of organic matter decomposition decreases with increasing temperature| indicated by the Q(10) decreasing with temperature to be about 4.5 at 10 degrees C and 2.5 at 20 degrees C. At low temperatures| the temperature sensitivity of decomposition was consequently much greater than the temperature sensitivity of net primary productivity| whereas the temperature sensitivities became more similar at higher temperatures. The much higher temperature sensitivity of decomposition than for net primary productivity has important implications for the store of soil organic C in the soil. The data suggest that a 1 degrees C increase in temperature could ultimately lead to a loss of over 10% of soil organic C in regions of the world with an annual mean temperature of 5 degrees C| whereas the same temperature increase would lead to a loss of only 3% of soil organic C for a soil at 30 degrees C. These differences are even greater in absolute amounts as cooler soils contain greater amounts of soil organic C. This analysis supports the conclusion of previous studies which indicated that soil organic C contents may decrease greatly with global warming and thereby provide a positive feed-back in the global C cycle. 2572,1995,3,2,THE USE OF MICROALGAE FOR ASSIMILATION AND UTILIZATION OF CARBON-DIOXIDE FROM FOSSIL FUEL-FIRED POWER-PLANT FLUE-GAS,The accumulation of carbon dioxide in the atmosphere| primarily as a result of the combustion of fossil fuels| has been linked to potential global climate change. Capture and utilization of the carbon dioxide by microalgae has emerged as a promising technology to help reduce emissions from fossil fuel-fired power plants. Microalgae are of particular interest because of their rapid growth rates and tolerance to varying environmental conditions. We are currently conducting experiments on the growth of microalgae exposed to simulated flue gas. This technology is envisioned for open raceway cultivation ponds as a low cost implementation strategy. Coupling the production of fuel or commodity chemicals with the use of flue gas carbon dioxide as a microalgal nutrient is envisioned to be a cost-effective method of reducing the amount of carbon dioxide contributed to the atmosphere by fossil fuel-fired power plants. 2570,1995,2,3,THERMAL SKIN-EFFECT AND THE AIR-SEA FLUX OF CARBON-DIOXIDE - A SEASONAL HIGH-RESOLUTION ESTIMATE,Understanding the: role the oceans play in sequestering anthropogenic CO2 is crucial to understanding global climate change. Correct parameterization of air-sea flux of CO2 is an important challenge to modelers. Recently it has been demonstrated that the thin thermal layer at the surface of the ocean can lead to an underestimate of CO2 solubility (Robertson and Watson| 1992) We re-evaluate the effect of the cool thermal skin anti present a high-resolution seasonal estimate of its effect on the air-sea| flux of CO2. We. compare air-sea flux estimates derived using both a mean wind field and a more realistic Rayleigh distribution of the wind field. Using the mean monthly wind stress and a linear relationship between wind speed and the gas exchange coefficient of CO2 (Tans et al.| 1990)| we estimate that excluding the southern ocean| the surface. skin correction increases the air-sea flux of carbon by 0.48 Ct yr(-1). This is 25% lower than the correction suggested by Robertson and Watson (1992) and the difference is attributed to the better temporal and spatial resolution of the present data set. When a more realistic representation of the temporally varying winds is used| the corrected carbon flux decreases to 0.36 Ct yr(-1) Conservatively| adding a. 10% contribution fi om the southern ocean| we estimate a mean global increase. in CO2 flux clue to the skin effect of 0.39 Ct C yr(-1) This is 40% lower than the previous estimate of Robertson and Watson (1992). Finally| adopting the gas transfer parameterization of Liss and Merlivat (1984)| we estimate a CO2 flux anomaly of only 0.17 Gt C yr(-1) which is approximately 50% lower than the analogous estimate using the Tans et al. (1990) formulation and a full 75% lower than the estimate of Robertson Watson (1992). These results suggest that both a proper representation of the wind speed/flux correlation and a realistic distribution of the wind field is essential in making large-settle flux estimates. We also examine the seasonal variation of the thermal skin effect. The largest negative temperature gradients (-0.75 degrees C) are found during the northern hemisphere winter in the regions of the. Kuroshio and the Gulf Stream Currents| whereas the central North Pacific has a small positive temperature gradient during the summer months. 2544,1995,5,4,THERMALLY ANOMALOUS ASSEMBLAGES REVISITED - PATTERNS IN THE EXTRAPROVINCIAL LATITUDINAL RANGE SHIFTS OF PLEISTOCENE MARINE MOLLUSKS,Pleistocene faunas of the eastern Pacific shelf are characterized by thermally anomalous species assemblages-i.e.| coexisting species that inhabit different climatic regimes today. We used data on the latitudinal ranges of 2887 extant molluscan species to determine the biological basis of the Pleistocene faunal migrations. Overall| the species exhibiting the most extensive range shifts (termed extraprovincial species) were not drawn randomly from the available species pool| and the pattern is climatically asymmetrical. The latitudinal ranges of southern extraprovincial species are significantly wider on average than those of the species pool from which they were drawn| but the ranges of northern extraprovincials resemble those of their parent pool. This contrast is primarily a consequence of the biogeographic structure of the eastern Pacific fauna; water-mass boundaries are more effective barriers for southern species migrating north in response to changing climatic conditions than for northern species moving south. Our analysis of Pleistocene marine mollusks provides a biological and environmental context for species response to environmental change and permits predictions about the movement of eastern Pacific species relative to major environmental barriers in the face of future global change. 4443,1995,3,4,THIRD-WORLD DEBT AND TROPICAL DEFORESTATION,The deforestation and degradation of tropical forests are taking place at an extremely rapid pace. According to the Food and Agriculture Organization (FAO)| the estimated annual rate of tropical deforestation during the 1981-1985 period was 113 846 square kilometers or 0.6% of the 1981 total forested area. The implications of the loss of these forests are staggering (Myers| N.| 1989. Deforestation Rates in Tropical Forests and Their Climatic Implications. Friends of the Earth| London). Tropical forests are extremely rich ecosystems which support a disproportionately large share of the world's plant and animal species. Forests play a crucial role in both nutrient and hydrological cycling and may provide sustainable economic benefits through managed harvesting of timber and the collection of non-timber products such as fruits| nuts| and rubber. Also| deforestation is a significant source of global warming through its effects on the global carbon cycle. This paper focuses on the relationship between debt and deforestation| examining conceptual and empirical arguments that debt is a source of deforestation pressure. Our study develops a behavioral model which suggests that debt can lead to myopic behavior| leading to deforestation rates that may not be optimal in the long run| but are necessary in the short run to meet current constraints. Then| country-by-country data on debt| deforestation| and other variables are analyzed with regression analysis. It is shown that debt is significantly correlated with deforestation under a wide variety of assumptions and specifications. Our results indicate that debt is an important factor in the deforestation of tropical countries. There are certainly other sources of deforestation| both micro- and macroeconomic| which may vary significantly from country to country. However| we focus on debt because of its dominant role in the economies of developing countries| and because of the increased use of debt-for-nature swaps. The link between debt and deforestation that is suggested in this paper implies that debt-for-nature swaps may have a dual effect on deforestation. First| the contractual agreement is designed to preserve forests as part of the swap. Second| the reduction in debt may itself reduce the pressure to deforest| although this indirect effect is small. Our research provides evidence that reducing debt reduces deforestation| which may be an argument to offer deforesting third-world countries some form of debt relief| and to utilize more fully debt-for-nature swaps as a tool for preserving environmental quality. 4384,1995,4,4,TIME-DOMAIN ANALYSIS OF SOFAR PROPAGATION IN LOW-LATITUDE SEA AREA BY WAVE THEORY AND RAY THEORY,In investigation into the phenomenon of global warming| ocean acoustic tomography (OAT) has been used for analysis. In this analysis method| the most important factor is exact calculation of the sound speed in water| that is| the sound wave propagation time. However| so far| analysis of SOFAR propagations in the low-latitude sea area has been lacking. Such a sea area is very important for analysis of the El Nino Current and others| although a special sound speed structure appears in the region of uniform sound speed formed around the SOFAR axis. For SOFAR propagation| we have compared time-domain results using two models| based on the measurement of far-range sound wave propagation in the sea east of Mindanao Island. The models chosen for the analysis are Stickler's normal mode method (SNM) and ray approximations. (The SNM time series is obtained via Fourier synthesis.) By this means we examined the characteristics of wave theory and ray theory in the low-latitude sea area.
4470,1995,3,4,Toxicological properties of halon substitutes,Halon fire extinguishing agents are used throughout the world to protect valuable electronics| oil and gas production operations| military systems| as well as a number of other critical facilities. Unfortunately| halons deplete stratospheric ozone| causing destruction at 3 to 16 times the rate of CFC-11 (a common refrigerant). As a consequence| the production of halons was prohibited on December 31| 1993 by an international treaty| the Montreal Protocol. This ban on halon production resulted in a search for replacement chemicals for firefighting and explosion protection applications. Replacements must satisfy the following three criteria in order to be successful candidates: effectiveness| cleanliness| and environmental acceptability (low ozone depletion and global warming potentials). It is also necessary that a replacement agent be as non-toxic as possible relative to possible exposures and generate minimal toxic and corrosive decomposition products during the suppression event. Herein| the toxicological aspects of halon replacements are discussed. The specific toxic endpoints of concern for halocarbon candidates| as well as the kinds of toxicity testing required for halon replacements| will be addressed. The paper will also provide a summary of the toxicological properties for the most promising near term halon replacements. Associated decomposition product formation will be briefly discussed. 2588,1995,2,4,Trees differ from crops and from each other in their responses to increases in CO2 concentration,Length of exposure| degree of maturity and type of tissue all affect the results obtained in response to elevated CO2 treatment of trees. Seedlings are most responsive and| in many cases| the first few weeks or months of exposure may set the pattern for future growth. Measurements of leaf photosynthesis and respiration are not good predictors for incorporation of carbon into tissue. Seasonal changes in non-structural carbohydrates| emissions of isoprenes from leaves and exudation from roots can 'waste' photosynthate. However| these are difficult or impossible to quantify. Currently| the only generalization that can be made is that growth will be accelerated but the magnitude of this depends on tissue type| nutrition and environmental conditions. The implications of this for a future elevated atmospheric CO2 world are complex. Interactions and competition between species should be incorporated into long-term studies. These studies must| themselves| be incorporated into appropriate models which take into account regional soils and climates for use in prediction of the effects of global climate change on trees and forests. 4466,1995,2,4,Trends of southern African sea level: Statistical analysis and interpretation,Records of monthly mean sea level from tide-gauge sites along the coast of Namibia and South Africa are examined for evidence of long-term trends. Four records (Luderitz| Port Nolloth| Simonstown and Mossel Bay) approach 30 years in duration. An exploratory statistical analysis revealed the presence of high frequency fluctuations| a distinct seasonal signal and a slowly varying interannual structure. The serial correlation suggested the use of Box-Jenkins models to separate out the various contributions and enabled statistical estimates of underlying trends in sea level with realistic error estimates to be made. A linear trend at Port Nolloth was significantly different from zero| and its consistency with the trend from the two other West Coast sites led to the conclusion that| over the past 30 pears| sea level has been rising on the west coast of Namibia and South Africa at a rate estimated at 0|12 +/- 0|04 cm . year(-1). By contrast there was no consistent upward trend at Mossel Bay on the South Coast. These estimates agree with recent published estimates of a global rate of rise in sea level| tempered by the movement of the land surface relative to the ocean to compensate for ongoing glacial isostatic adjustment. Consequently estimates of future rise in sea level attributable to global warming can be extrapolated to the coasts of Namibia and South Africa. 2581,1995,4,4,TROPICAL INTERANNUAL VARIABILITY IN A GLOBAL COUPLED GCM - SENSITIVITY TO MEAN CLIMATE STATE,A global coupled ocean-atmosphere-sea ice general circulation model is used to study interannual. variability in the Tropics. Flux correction is used to control the mean climate of the coupled system| and in one configuration of the coupled model| interannual variability in the tropical Pacific is dominated by westward moving anomalies. Through a series of experiments in which the equatorial ocean wave speeds and ocean-atmosphere coupling strength are varied| it is demonstrated that these westward moving disturbances are probably some manifestation of what Neelin describes as an ''SST mode.'' By modifying the flux correction procedure| the mean climate of the coupled model can be changed. A fairly modest change in the mean climate is all that is required to excite eastward moving anomalies in place of the westward moving SST modes found previously. The apparent sensitivity of the nature of tropical interannual variability to the mean climate state in a coupled general circulation model such as that used here suggests that caution is advisable if we try to use such models to answer questions relating to changes in ENSO-like variability associated with global climate change. 4302,1995,4,2,Tropical seasonal forests in monsoon Asia: With emphasis on continental southeast Asia,This paper is intended to provide a brief review of the tropical seasonal forest| one type of the tropical moist forests in monsoon Asia. It will also focus on and summarise issues of current concern in relation to their depletion and global environmental issues. Tropical moist forests occur in the rainy tropical and monsoon tropical climate types. The tropical moist evergreen forest or the tropical rain forest| which account for two-thirds of the tropical moist forests are rich in biodiversity and contain valuable tropical hardwood. The tropical moist deciduous forest or the tropical seasonal forest which lie along the fringes of tropical rain forest| are less complex than the tropical rain forest and have more distinct wet and dry periods. Broadleaved deciduous trees of the genera Tectona| Shorea| and Dipterocarpus are predominantly in this forest type. Currently estimates have found that more than 17 million hectares of forest mainly tropical moist forests are being lost each year. There is a widespread recognition that agriculture and the burning of tropical moist forests contribute to global warming but to a much lesser extent than the combustion of fossil fuels and industrial activities in the developed world. 4297,1995,4,3,Twentieth-century variability in snow-cover conditions and approaches to detecting and monitoring changes: Status and prospects,The extent| and variability of seasonal snow cover are important parameters in the climate system. Changes in snow cover may provide an indicator of global climatic trends and are of considerable practical significance. The question of the most suitable indices of changes in snow cover conditions| in terms of their use for change detection and for monitoring applications| is discussed. The use of passive microwave-derived estimates of snow cover extent and water equivalent for continental and regional-scale mapping is illustrated. Problems in interpreting the microwave signatures| as well as difficulties in comparing such data to ground observations| are also noted. Up to now analyses have focused primarily on trends in Northern Hemisphere snow extent based on monthly averages using the NOAA weekly snow charts 1972-present| or on station data spanning 50-100 years. However| the latter are generally less readily available| or accessible. An overview is provided of current information on recent hemispheric trends and| for the former USSR| the relationship of changes in snow depth| to variations in temperature and precipitation since the late nineteenth century are described| based on newly available station records. Interpretation of these changes and comparisons with other records are presented. Model projections of changes in snow cover conditions and associated snowmelt runoff that may occur as a result of greenhouse gas-induced warming are discussed for several mountain regions. Long-term station records of snow depth variability provided a valuable context within which such modeling results can be examined. 2609,1995,3,3,US country studies program: An example of bilateral assistance to developing countries on climate change,Under the UN Framework Convention on Climate Change (UNFCCC) developing and transition countries are eventually required to report greenhouse gas (GHG) emissions inventories and response (mitigation) options. The United States (US) and other donors are providing financial and technical support for climate change country studies to help meet their needs under the UNFCCC The US Country Studies Program (US CSP) was originally announced by President Bush at the United Nations Conference on Environment and Development (UNCED) in Brazil in 1992. The Program is currently assisting 56 country studies to address climate change. There are strong components of ocean and coastal assessment| adaptation and management in 41 of the 56 studies in the US CSP. All studies in the Program are implemented under respective bilateral cooperative agreements. Technical assistance for conducting GHG inventory| climate change impact vulnerability studies| and adaptation and mitigation assessments includes training of analysts| sharing of contemporary tools and assessment techniques| implementation of information-sharing workshops| and an exchange program for analysts. Emphases have been put on strengthening of human and institutional capacity to cope with global climate change issues| hence providing developing and transition countries with a sustained basis for meeting the goals of the UNFCCC. 4389,1995,4,4,VARIATIONS AND TRENDS IN ANNUAL MEAN AIR TEMPERATURES IN TURKEY WITH RESPECT TO CLIMATIC VARIABILITY,The purpose of this study is to investigate the variations and trends in the long-term annual mean air temperatures by using graphical and statistical time-series methods. The study covers a 63-year period starting from 1930 and uses temperature records from 85 climate stations. First| spatial distributions of the annual mean temperatures and coefficients of variation are studied in order to show normal conditions of the long-term annual mean temperatures. Then variations and trends observed in the annual mean temperatures are investigated using temperature data from 71 climate stations and regional mean series. Various non-parametric tests are used to detect abrupt changes and trends in the long-term mean temperatures of both geographical regions within Turkey and individual stations. The analyses indicate some noticeable variations and significant trends in the long-term annual mean temperatures. Among the geographical regions| only Eastern Anatolia appears to show similar behaviour to the global warming trends| except in the last 5 years. All the coastal regions| however| are characterized by cooling trends in the last two decades. Considering the results of the statistical tests applied to the 71 individual stations data| it could be concluded that annual mean temperatures are generally dominated by a cooling tendency in Turkey. The coldest years of the temperature records of the majority of the stations were 1933 and 1992| respectively. 2552,1995,2,4,Water chemistry and periphyton in an alpine wetland,Remote high elevation sites are thought to be good sites to monitor global change and anthropogenic effects on ecosystems. This study was conducted during 1987-1990 in a high elevation wetland (3593 m) located in the Green Lakes Valley| Front Range| Colorado (USA). Salix spp. was the dominant riparian species in this 2 ha. wetland. Small shallow pools (<0.5 m depth) constituted a water area of 236 m(3). The major source of water during the study period was snowmelt. The wetland had a well defined outlet and inlet| although an undetermined amount of water entered as groundwater from the snow patch above. Outlet discharge was 424-460 m(3) during the month of July and declined thereafter as water input from the snowpatch declined. Inlet discharge was 67% of outlet discharge. Water temperatures in the outlet were always less than 6.8 degrees C| pH 6.0-6.3| and mean conductivity 30.8 mu S cm(-1). Both NO3- and SO4-2 were higher in the inlet than in the outlet. Dominant cations in the inlet and outlet waters 4 were Ca+2 much greater than Mg+2 > K- > Na-; dominant anions were SO4-2 much greater than HCO3- > NO3- much greater than Cl-. Nutrient limitation 4 by P was demonstrated once using nutrient diffusing substrata. No limitation could be shown for NO3-| HCO3-| or Fe+EDTA. Slow colonization rates of periphyton on tiles were attributed to low temperatures and/or ultraviolet radiation. However| interannual differences in biomass on tiles were as much as 300% after 35 days. A minimum of 16-54 samples would be needed to detect a significant interannual change in biomass on tiles after 35 days assuming that the extreme case for periphyton patchiness. Global climate change is likely to affect discharge and water temperature in this wetland which will have direct and indirect affects on population dynamics and ecosystem function. 4476,1995,2,4,WATER-QUALITY MANAGEMENT - CAN WE IMPROVE INTEGRATION TO FACE FUTURE-PROBLEMS,Water (and its deteriorating quality) may be the most severe stress on the exponentially growing human population in the next century. Problems are becoming increasingly complex and diverse and require more and more specific knowledge| and efficient integration across various disciplines| sectors| countries| and societies. The major challenge addressed is whether we are prepared to realize the desired integration and to resolve the large amount of existing gaps and barriers. The paper analyzes major past and desired future trends in water quality management. A number of issues are selected such as the identification| occurrence| and perception of various problems (e.g. eutrophication| acidification| global warming)| pollution control types| wastewater treatment| modeling and monitoring| planning and environmental impact assessment| legislation and institutions| the notion of sustainable development| and the role of science and engineering. The past two decades showed tremendous developments in water quality management. in spite of these| the focus of the present discussion lies mostly on pitfalls to disseminate lessons and questions which are crucial to likely future problems and desired improvements. 4347,1995,2,3,WATER-VAPOR FEEDBACK OVER THE ARCTIC-OCEAN,Previous studies of the clear sky greenhouse effect and water vapor feedback have focused on subpolar regions. In view of modeled amplification of greenhouse warming in the Arctic we investigate the humidity characteristics| clear sky greenhouse effect and water vapor feedback in the Arctic by using 10 years of radiosonde data obtained from the Russian drifting ice island stations along with a radiative transfer model. By taking advantage of the natural variability associated with seasonal and interannual variations| we can infer the water vapor feedback from the data. Results of this study indicate that water vapor feedback over the Arctic Ocean is substantially more complex than in other regions because of the relative lack of convective coupling between the surface and the atmosphere and the different thermodynamic and radiative environment in the Arctic. In particular| the effect of water vapor on the net flux of radiation is complicated by low temperatures| low amounts of water vapor| and the presence of temperature and humidity inversions. During winter a ''hyper'' water vapor feedback arises from the control of ice saturation on the lower tropospheric humidity and a water vapor ''window'' in the rotation band at low atmospheric humidities. Implications for global warming are discussed. 2561,1995,4,4,WIMOVAC - A SOFTWARE PACKAGE FOR MODELING THE DYNAMICS OF PLANT LEAF AND CANOPY PHOTOSYNTHESIS,The ability to predict net carbon exchange and production of vegetation in response to predicted atmospheric and climate change is critical to assessing the potential impacts of these changes. Mathematical models provide an important tool in the study of whole plant| canopy and ecosystem responses to global environmental change. Because this requires prediction beyond experience| mechanistic rather than empirical models are needed. The uniformity and strong understanding of the photosynthetic process| which is the primary point of response of plant production to global atmospheric change| provides a basis for such an approach. Existing modelling systems have been developed primarily for expert modellers and have not been easily accessible to experimentalists| managers and students. Here we describe a modular modelling system operating within Winnows to provide this access. WIMOVAC (Windows Intuitive Model of Vegetation response to Atmosphere and Climate Change) is designed to facilitate the modelling of various aspects of plant photosynthesis with particular emphasis on the effects of global climate change. WIMOVAC has been designed to run on IBM PC-compatible computers running Microsoft Windows. The package allows the sophisticated control of the simulation processes for photosynthesis through a standardized Windows user interface and provides automatically formatted results as either tabulated data or as a range of customizable graphs. WIMOVAC has been written in Microsoft Visual Basic| to facilitate the rapid development of user-friendly modules within the familiar Windows framework| while allowing a structured development. The highly interactive nature of controls adopted by WIMOVAC makes it suitable for research| management and educational purposes. 4351,1995,3,4,ZERO ODP| ZERO GWP| HALOGEN-FREE| AND LOW K-FACTOR AZEOTROPES AS BLOWING AGENTS FOR ISOCYANATE-BASED FOAMS,Due to the ozone depletion potential (ODP) problem of CFCs and HCFCs| a number of alternative physical blowing agents for isocyanate-based foams are being investigated. Among them| two representative candidates are HFCs (hydrofluorocarbons) and halogen-free| aliphatic hydrocarbons in which major hydrocarbons are n-pentane and cyclopentane. Another accompanying problem of CFCs and HCFCs is global warming potential (GWP). This paper describes azeotropic blowing agents (hereinafter referred to as AZBs [32|33]) having no halogens. The AZBs employed in this study comprise a C-5-C-7 hydrocarbon and a compound selected from the group consisting of C-2-C-4 carboxylic acid esters| C-3-C-4 ketones| and C-4 ethers. These halogen-free azeotropes have advantages of zero ODP| zero GWP| and lower K-factor. The AZBs have the following advantages over HFCs and hydrocarbons: (a) they have a minimum boiling point and thus give more efficient blowing action than that of the respective individual components| resulting in lower density foams; (b) the AZBs-blown foams have lower K-factor than that of the foams blown with the respective individual blowing agents; (c) the adequate polarity of the AZBs exhibits better compatibility with foaming ingredients and results in finer celled foams than by the use of a single hydrocarbon blowing agent| e.g.| cyclopentane; (d) due to the similarity of boiling points and polarity of the AZBs with those of CFC-11| the AZBs are a direct replacement for CFC-11 without any change of CFC-11-based formulations and without the use of special raw materials; (e) in general| the foam density is roughly proportional to the number of moles of blowing agent; the AZBs have lower molecular weights than CFC-11 and therefore| smaller amounts can be used. Also their costs are far less than that of CFCs or HCFCs; (f) the AZBs have zero ODP| zero GWP| and are halogen-free; therefore| there are no environmental problems. A number of the AZBs can be used as blowing agents| for example a blend of n-pentane/methyl formate at a weight ratio of 47/53. The blend has a boiling point of 21.8 degrees C| which is almost equal to that of CFC-11. The AZBs can be used for various isocyanate-based foams| e.g.| flexible and rigid methane foams| modified isocyanurate foams| urea foams| flexible and rigid integral skin foams. 4418,1995,3,4,ZERO-ODP RIGID INSULATION FOAMS PREPARED WITH HFAS,The industry is continuously being challenged by regulatory agencies to find alternatives to CFCs (chlorofluoro-carbons) for use in all applications. Two solutions investigated were to replace CFCs with HCFCs Olydrochloro-fluorocarbons or PFAs (perfiuoroalkanes). However| the contribution of HCFCs to the depletion of the ozone layer has been determined to be too high for them to be viewed as anything but an intermediate solution. PFAs have been getting attention for their high halogen global warming potential (HGWP) due to their long atmospheric lifetime and| thus| seem unlikely even as additives. At this time| it appears that both HCFCs and PFAs have a finite usage period in our industry. In our search for alternatives| we have discovered that HFAs (hydrofluoroalkanes or partially fluorinated alkanes) make fine| closed cell foams. As a result of this| HFA-blown rigid foams at 2.0 pcf density or lower have low initial k-factors (0.13 Btu in./hr ft(2) degrees F). Aged k-factors are excellent because of the relatively slow cell gas diffusion of HFAs. These insulation values are similar to or better than those of foams made with HCFCs and PFAs! The advantage to this technology is that HFAs have zero-ozone depletion potential (ODP) and relatively low HGWP| making HFAs viable long-term alternatives. Processing of the alternatives evaluated is similar to HCFC-22 technology| because the HFAs used in this investigation are gases at room temperature and pressure. The HFAs examined in this study were HFA-32| 134a| 125| and 227. These HFAs all show the same characteristics of low solubility| low blowing efficiency| and higher working vapor pressures; therefore| emulsion technology was used (as with PFAs). Good quality foams were produced without utilizing special compatibilizers. 2501,1996,2,3,A fuzzy rule-based approach to drought assessment,A methodology for predicting regional droughts from atmospheric pressure patterns is presented. Drought characteristics are strongly related to general circulation patterns (CP). CPs are determined from daily atmospheric pressure data. The link between large-scale CPs and regional scale droughts is modeled using a fuzzy rule-based approach. A fuzzy rule-based model operates on an ''if'' --> ''then'' principle| where ''if'' corresponds to a vector of fuzzy inputs and ''then'' corresponds to some fuzzy consequences. The rules are derived from a so-called training set which includes a daily time series of CP classes and a corresponding monthly sequence of Palmer Drought Severity Indices (PDSI). Split sampling of historical data available for a 35-year time period is used to derive and then to validate the rules. Then| these fuzzy rules may be applied to predict droughts in terms of atmospheric circulation patterns. The occurrence and persistence of CPs are expected to vary under global climate change. Thus the approach may also be useful in estimating the potential impact of climatic change (e.g.| 2 x CO2 scenario) on droughts. The methodology is illustrated using drought index data from New Mexico and atmospheric pressure data over the western United States. 4145,1996,2,4,A mechanistic model for submerged aquatic macrophyte photosynthesis: Hydrilla in ambient and elevated CO2,There are significant knowledge gaps about the responses of submerged aquatic macrophytes to CO2 enrichment and global warming. A mechanistic steady-state photosynthesis model for submerged aquatic macrophytes was developed to provide an analysis tool to investigate the responses of plant photosynthesis to CO2| temperature and light. The model was based upon a general simplified scheme for inorganic carbon assimilation of submerged aquatic macrophytes which integrated the knowledge about aquatic plant photosynthesis from previous research| mainly on Hydrilla. The model includes: (1) diffusion and/or active transfer of inorganic carbon (CO2 and/or HCO3-) in the bathing medium into the leaf mesophyll and cytosol; (2) diffusion and/or 'pumping' of CO2 through the PEPcase-related C-4 pathway into the chloroplast; (3) inter-conversions between CO2 and HCO3- inside cells; (4) photosynthetic carbon reduction cycle (PCR) in the chloroplast. In the model| the PCR processes in the chloroplast were described using the widely accepted C-3 photosynthesis model. The activity of the C-4 cycle was related to environmental CO2 'stress'. In this way| the model can simulate the shift between C-3-like and C-4-like photosynthesis under different environmental conditions. The model was validated using gas exchange data from Hydrilla plants grown in ambient and elevated CO2. The model predicted quite well photosynthetic responses to incident PAR| temperature and ambient CO2 for both ambient and elevated atmospheric CO2 treatments. Model predictions agreed well with measured Hydrilla gas exchange data. The simulated and measured CO compensation points of Hydrilla leaf photosynthesis were about 100 ppm. The light compensation point of photosynthesis was about 25 mu mol m(-2)s(-1) (PAR)| and photosynthesis rate was saturated at about 100 mu mol m(-2)s(-1) (PAR). Higher pH slightly increased photosynthesis rates at ambient CO2 (similar to 350 ppm). There was no significant acclimation of Hydrilla photosynthesis to elevated CO2 within the experimental period. Simulated CO2 compensation point decreased with increasing activity of C-4-cycle processes. 4147,1996,2,4,A method for monitoring long-term population trends: An example using rare arctic-alpine plants,Populations of arctic-alpine plants at the southern periphery of their range should respond rapidly to projected global warming. We established a study to monitor the density and reproductive effort of six such species in tundra of Glacier National Park| Montana to help project the fate of these species in the center of their range. For many species| detecting long-term population trends is confounded by short-term variation. Our study design employs temporal resampling of permanent plots on multiple sites and a repeated-measures model that accommodates the effects of high frequency variation and allows assessment of the significance of long-term trends. Statistical analysis compares site-specific estimates of annual mean density between two time periods and uses between-plot| within-site| within-year variation to estimate error. Power calculations using data from the 3-yr baseline period indicate that measurements of fecundity will be less sensitive for detecting long-term trends than measurements of plant density. Furthermore| our results suggest that perennial species of closed-turf communities may be better bioassays of long-term change than annuals or species of open| ephemeral microsites. 4264,1996,3,4,A multinational model for CO2 reduction - Defining boundaries of future CO2 emissions in nine countries,A need to make substantial future reductions in greenhouse gas emissions would require major changes in national energy systems| Nine industrialized countries have explored the technical boundaries of CO2 emission restrictions during the next 40 to 50 years using comparable scenario assumptions and a standard model| MARKAL| Quantitative results for the countries are shown side by side in a set of energy maps that compare the least-cost evolution of the national energy systems by the main factors that contribute to CO2 emissions| The ability to restrict future CO2 emissions and the most cost-effective measures for doing so differ among the countries; an international agreement that would mandate substantial emission restrictions among countries by an equal percentage reduction is clearly impossible| The results are a first step toward a basis for allocating such international reductions| and the multinational process by which they were produced provides an example for further international greenhouse gas abatement costing studies. 4178,1996,3,4,A preliminary comparative study of three manure composting systems and their influence on process parameters and methane emissions,Three cattle manure composting systems - windrowing| forced aeration with temperature feedback control and simple minimal intervention (manure stacks - ''passive composting'') were compared with respect to specifically selected and operationally important process parameters including dry matter| moisture and volatile solids losses| volume reduction and bulk density changes. The windrowing method proved to be the most effective with respect to the above parameters. Preliminary investigations of methane from the three systems during processing showed that the minimal intervention method produced high levels of methane (> 4 percent) in the waste matrix. The intervention methods| of windrowing or forced aeration| drastically reduced methane output. The importance of animal manures in global agriculture| with reference to methane emissions and global warming| is briefly reviewed. The widespread reliance of manure disposal by the use of simple stacks|sometimes erroneously elevated to a processing status by use of the term ''passive composting''| is questioned on ecological and environmental grounds. The data from this preliminary study shows the enormous impact that simple windrowing techniques can achieve in terms of organic waste conversion and product quality| concomittant with ecologically acceptable treatment routes. 2471,1996,2,3,A simplified climate model with combined atmospheric-hydrological processes,Global climate change can be reproduced in detail by using three-dimensional general circulation models (GCMs). However| such complex models require super-computers and extensive hours of computational time for a single attempt at reproducing long term climate change. An alternative approach is to make simplifying assumptions that retain the essential physics for the desired simulation. Energy balance and radiative-convective models are examples of such models. The model in this study follows the simplified approach using physics-based climate processes as well as interactions between atmospheric and hydrological processes. The vertically and latitudinally averaged mean temperature and mean water vapour content between 30 degrees N-50 degrees N latitudes are considered as atmospheric state variables while soil and sea temperatures and water storage amount are considered for describing the behaviour of the hydrological system. Temperatures in both the atmosphere and ground are calculated by a thermal energy equation that considers the physically-based processes of shortwave radiation| longwave radiation| sensible heat flux| and latent heat flux. precipitation and evaporation processes transport moisture between the atmosphere and ground. In this study| the radiation parameterization of the simplified climate model is tested in the investigation of the various effects of global warming due to doubling and quadrupling of CO2. Changes of temperature| soil water content| evaporation rate and precipitation rate are investigated by numerical experiments. The simplified climate model provides acceptable simulation of climate change and holds promise for practical investigations such as the interactions of physical processes in the evolution of drought phenomena. 4116,1996,4,4,A statistical method for separating urban effect trends from observed temperature data and its application to Japanese temperature records,Separating the impact of urbanization (urban effect temperature trends) from observational data at urban monitoring sites is an important problem in the detection of global warming impacts. A statistical method using principal component analysis of the temperature data in an area was developed to separate the urban effect temperature trend from the observed temperature record at urban stations; including those without nearby rural reference stations. After the mathematical description of the method| an example of the analysis for model data on which some trends are superimposed (given) at any stations was shown for an explanation of the method. This example not only clarified the performance (impact| weight) of the superimposed trend in the trend for each principal component score (Z-score) but also showed how all the superimposed trends were separated from the model data by this method. This method was applied to monthly mean temperature data for the past 73 years (1920-1992) from 51 meteorological stations in Japan| and the urban effect temperature trend at each station was separated from the observed temperature trend. As a result of the analysis| it was clarified that in Japan the maximum urban effect temperature trends at stations with a population of over 100 thousand in 1993 were 1.0-2.5 degrees C/100 years| which were almost the same as those in the United States and China. The urban effect temperature trends in big cities are larger in the cold season than in the warm season| being maximum in winter or autumn and minimum in summer. After removing the urban effect temperature trend| the annual mean temperature trends at stations in Japan over the period analyzed ranged from 0.5 degrees C/100 years in northern Japan to 1.1 degrees C/100 years in western Japan with the areal mean for Japan of 0.8 degrees C/100 years. The positive trends are most notable in winter and spring (December to May)| and show areal mean values of 1.0-1.6 degrees C/100 years with the maximum in March. On the other hand| they are not marked in summer and autumn. In particular| in the northern part of Japan| negative trends appear from July to November. The area with negative trends below -1.0 degrees C/100 years extends over most of the northeastern half of Japan in July| but does not reach the southern part of Japan| which has a slight positive trend. As a result of these regional differences in temperature trends| the north-south temperature gradient increases in summer and autumn with the maximum trend difference of 2.0 degrees C/100 years in July and October. 4204,1996,4,3,A welfare-based index for assessing environmental effects of greenhouse-gas emissions,THE global warming potential (GWP) index(1-3) is a measure of the relative contribution of the emissions of different greenhouse gases to the radiative forcing of the atmosphere-and thus to climate change-over a given time period. But this index does not represent the effects of climate change| and therefore does not provide an adequate basis for policy decisions about emissions reductions. This inadequacy has led to the proposal of an alternative| the economic-damage index (EDI)(4-7). This index compares the effect of different greenhouse-gas emissions on global economic welfare. Here we use a simple climate model to calculate the EDIs for a range of climate-change/greenhouse-gas emission scenarios| and compare the values to the corresponding GWPs. Although the values of these indices are| at this stage| broadly similar in both magnitude and uncertainty| the prospects of reducing these uncertainties by future research are better for the EDI. 4190,1996,4,4,Accelerating ground warming in the Canadian Prairie Provinces: Is it a result of global warming?,The results of precision temperature logs made to depths of several hundred meters in some 80 wells in Western Canada| most of which are located in the Prairie Provinces| show evidence of warming at the ground surface in the 0.5 g to 3.5 K range (average = 2.2+/-0.7 K| for 80 unevenly distributed sites). Modeling shows that this warming mostly pertains to this century and it has been most substantial in the last four decades if the ''ramp'' function of the linear increase of surface temperature is assumed. Using the ''step function'' model's increase of surface temperature (land clearing| forest fires| etc.) the calculated onset of warming would pertain mostly to the last two decades. Contour maps of ground temperatures currently and previously and a contour map of the ground warming magnitude delineate a large regional character of the ground temperature change at the southern margin of permafrost for the large area of the Prairie Provinces. In many cases however| the magnitude of ground warming is much larger than the magnitude of air warming. This is especially evident for the northern areas of Alberta in the boreal forest ecoprovince. The magnitude of ground warming is equal to the magnitude of surface air warming in southern Alberta in the grassland and aspen parkland ecoprovinces. The analysis of the temperature depth response to the surface warming from well data shows the integrated effect of surface air warming together with the increases in ground temperature due to natural terrain effects and other anthropogenical changes to the surface of the earth. 4122,1996,2,2,Adapting to sea-level rise: Relative sea-level trends to 2100 for the United States,Global sea levels have slowly risen during this century| and that rise is expected to accelerate in the coming century due to anthropogenic global warming. A total rise of up to 1 m is possible by the year 2100 (relative to 1990). To deal with this change| coastal managers require site-specific information on relative (i.e.| local) changes in sea level to determine what might be threatened. Therefore as a first step| global sea-level rise scenarios need to be transformed into relative sea-level change scenarios which take account of local and regional factors| such as vertical land movements| in addition to global changes. Even present rates of relative sealevel rise have important long-term implications for coastal management-projecting existing trends predicts a relative sea-level rise from 1990 to 2100 of up to 0.4 m and 1.15 m for the Mid-Atlantic Region and Louisiana| respectively. Ignoring sea-level rise will lead to unwise decisions and increasing hazard with time. This article adapts the Intergovernmental Panel on Climate Change (IPCC) global scenarios for sea-level rise (Warrick et at| 1996) to three relative sea-level rise scenarios for the contiguous United States. These scenarios cover the period 1990 to 2100 and provide a basis to assess possible proactive measures for sea-level rise. However| they are subject to the same uncertainties as the global scenarios as most of the sea-level rise will occur decades into the future. When considering what should be done now in response to future sea-level rise| given these large uncertainties| if is best to identify (I) low-cost| no regret responses which would maintain or enhance the choices available to tomorrow's coastal managers; and (2) sectors where reactive adaptation would have particularly high costs and where allowance for future sealevel rise can be considered a worthwhile ''insurance policy. '' Sea-level rise will impact an evolving coastal landscape which already is experiencing a range of other pressures. Therefore| to be most effective| responses to sea-level rise need to be integrated with all other planning occurring in the coastal zone. 4175,1996,3,4,Alternatives to slash-and-burn: A global imperative,Our generation has seen an upswelling of interest and concern for atmospheric pollution and for the concomitant destruction or degradation of our natural resources. High on the list of both these concerns is the rapid destruction of tropical forests and their release of greenhouse gases in the process. Much of the forest destruction is to provide lumber for building construction worldwide| and for fuelwood| but most of it is to provide land for agriculture. 4246,1996,3,4,Amazonian deforestation and global warming: Carbon stocks in vegetation replacing Brazil's Amazon forest,Carbon stocks in vegetation replacing forest in Brazilian Amazonia affect net emissions of greenhouse gases from land-use change. A Markov matrix of annual transition probabilities was constructed to estimate landscape composition in 1990 and to project future changes| assuming behavior of farmers and ranchers remains unchanged. The estimated 1990 landscape was 5.4% farmland| 44.8% productive pasture| 2.2% degraded pasture| 2.1% 'young' (1970 or later) secondary forest derived from agriculture| 28.1% 'young' secondary forest derived from pasture| and 17.4% 'old' (pre-1970) secondary forest. The landscape would eventually approach an equilibrium of 4.0% farmland| 43.8% productive pasture| 5.2% degraded pasture| 2.0% secondary forest derived from agriculture| and 44.9% secondary forest derived from pasture. An insignificant amount is regenerated 'forest' (defined as secondary forest over 100 years old). Average total biomass (dry matter| including below-ground and dead components) was 43.5 t ha(-1) in 1990 in the 410 X 10(3) km(2) deforested by that year for uses other than hydroelectric dams. At equilibrium| average biomass would be 28.5 t ha(-1) over all deforested areas (excluding dams). These biomass values are more than double those forming the basis of deforestation emission estimates currently used by the Intergovernmental Panel on Climate Change (IPCC). Although higher replacement landscape biomass decreases net emissions from deforestation| these estimates still imply large net releases. 2506,1996,3,3,An inventory of greenhouse gas emissions in Bangladesh: Initial results,In this paper| we present an inventory of greenhouse gas sources and sinks in Bangladesh for the year 1990. Because CO2 is believed to be the principal contributor to global climate change worldwide| and energy use is the largest source of CO2 emissions| much effort was made to analyze the Bangladesh energy system. Carbon emissions and carbon uptake in forests were also accounted for. Emissions of methane from agriculture| livestock| and urban landfill waste were also included in the inventory. In 1990| energy production using fossil fuels accounted for 15.5 Tg of CO2 emissions. Carbon emissions resulting from forestry were also calculated. It was found that about 5.46 Tg of carbon was removed/consumed from the forest sources in 1990. On the other hand| about 12.32 Tg of carbon was taken up in forests. Based on these numbers| which exclude bamboo| the forests of Bangladesh acted as a net sink for approximately 6.86 Tg of carbon in 1990. Methane emissions in 1990 from flooded rice cultivation ranged between 257 and 622 Gg| with a median of 439 Gg CH4. Methane emissions from the livestock sector were about 453 Gg CH4. About 5.92 Gg CH4 are emitted due to venting| flaring| and transmission and distribution of natural gas. Methane emissions from landfilled wastes in the major urban areas of Bangladesh contributed approximately 74 Gg CH4. 2537,1996,3,3,An inventory-based procedure to estimate economic costs of forest management on a regional scale to conserve and sequester atmospheric carbon,Estimation of the costs of managing forests to conserve and sequester atmospheric carbon is necessary to define the role of forests to mitigate the onset of projected global climate change. The role of forests as both carbon pools and an element in the flux of atmospheric carbon dictate new requirements in estimating the costs of forest management to mitigate climate change. These requirements include recognition of the inventory as a capital stock in the estimation of the costs; the need to allow the integration of biological| social and economic considerations across nations and regions; and the need to facilitate consideration of the distributional impacts of forest policy alternatives. An inventory-based procedure is presented to estimate forest management costs based on recognition of the opportunity costs of holding forest inventories. To demonstrate this procedure| the costs of four policy scenarios projected in the carbon budget of the United States are examined. Based on the demonstration| the inventory-based procedure is shown to meet the requirements for estimating forest management costs to conserve and sequester atmospheric carbon on a regional scale. The demonstration also illustrates the potential of the procedure to provide insights into differences in costs associated with management of forest ecosystems among geographic regions and forest policies. 4257,1996,3,4,An overview of recent technical developments in polyurethanes .1. General introduction and substitutes for chlorofluorocarbons (CFCs) and their applications,An overview of recent technological developments in polyurethanes is presented. Substitutes for CFCs in foams are reviewed in light of environmental considerations (ODP - ozone depletion potential and GWP - global warming potential). New developments in raw materials for the polyurethane industry are cited. 4240,1996,2,4,Appearance in Hungary of Cephalosporium maydis Samra| Sabet and Hingorani| causing late milt disease in maize,The microscopic fungus Cephalosporium maydis Samra| Sabet and Hingorani| which causes late wilt disease in maize| has been isolated for the first time in Hungary. According to the literature the pathogen is only known at present to cause economic damage in Egypt and India The fungus is seedborne| so it can be assumed that it reached Hungary through the import of infected propagation stock It causes a disease of the vascular bundles| the first symptoms of which can be observed in maize at tasselling. Diseased plants have retarded development| then wilt and finally. dry up. The vascular bundles become discoloured and cavities are formed in the pith. It is highly probable that global warming and the dry weather experienced in early summer over the last decade or so have played a decisive role in the appearance and activity of the pathogen in Hungary. If the climate continues to warm up| the significance of this disease could increase under Hungarian conditions| so it is important to carry out further studies both on the pathogen itself and on the resistance of cultivated hybrids and lines| and to elaborate effective methods of chemical control. 4199,1996,4,3,Assessment of the costs of global warming on a full fuel cycle basis,This paper reports on external cost assessments of the coal and natural gas to electricity fuel cycles conducted within the ExternE Project of the European Commission. This project leads the development of the impact pathway| or damage function approach for analysis of the environmental and social impacts of energy use. The methodology allows highly detailed and spatially disaggregated analysis of pollutant damage| following a logical progression from characterisation of emissions| through modelling of pollutant dispersion and atmospheric lifetime| to determination of impacts using appropriate dose-response functions| and associated economic costs. The project team is multi-disciplinary and the various models used have been the subject of international review. Assessment of the effects of climate change is at a less advanced state than analysis of| for example| air pollution effects on health| materials and crops| or occupational health impacts. However| preliminary results are available based on a review of damage estimates from the available literature| and a more detailed methodology is being developed. Both are described in this paper| together with a review of the major uncertainties. 4202,1996,4,4,Atmospheric fate and greenhouse warming potentials of HFC 236fa and HFC 236ea,The rate coefficient for the reaction OH + CF3CH2CF3 (1|1|1|3|3|3-hexafluoropropane| HFC236fa) was measured between 269 and 413 K using the pulsed photolysis-laser: induced fluorescence technique to be k(1) = (1.60 +/- 0.40) x 10(-12) exp (-(2450 +/- 150)/T) cm(3) molecule(-1) s(-1). The rate Coefficient| k(2b)| for the destruction of CF3CH2CF3 via reaction with O(D-1) was measured to be (4.5 +/- 1.9) x 10(-12) cm(3) molecule(-1) s(-1) using the laser photolysis-resonance fluorescence technique. From these data| along with previously published rate coefficients for OH reaction with HFC236ea| the atmospheric lifetimes of HFC238fa and HFC236ea were calculated to be 210 and 8.1 years| respectively. The room temperature infrared absorption cross sections for these two compounds were measured over the range 650 to 1350 cm(-1) The global warming potentials (GWPs) of HFC236fa and HFC236ea| respectively| were calculated to be 5610 and 2200 for a 20-year horizon and 5160 and 220 for a 500-year horizon. 4288,1996,3,4,Barriers to energy efficiency in vehicle design,This paper reviews the factors undermining a stabilization in vehicular emissions of CO2 in line with commitments made at the Rio Conference| 1992. Despite effective technologies to reduce such emissions| resistance to more fuel-efficient cars from manufacturers and consumers combined with increased usage means that no progress has been made as yet. 4114,1996,4,4,Biodiversity and industry ecosystem management,The term biodiversity describes the array of interacting| genetically distinct populations and species in a region| the communities they comprise| and the variety oi ecosystems of which they are functioning parts. Ecosystem health| a closely related concept| is described in terms of a process identifying biological indicators| end points| and values. The decline of populations or species| an accelerating trend worldwide| can lead to simplification of ecosystem processes| thus threatening the stability and sustainability of ecosystem services directly relevant to human welfare in the chain of economic and ecological relationships. The challenge of addressing issues of such enormous scope and complexity has highlighted the limitations of ecology-as-science. Additionally biosphere-scale conflicts seem to lie beyond the scope of conventional economics| leading to differences of opinion about the commodity Value oi biodiversity and of the services that intact ecosystems provide. In the face of these uncertainties| many scientists and economists have adopted principles that clearly assign burdens of proof to those who would promote the loss of biodiversity and that also establish ''near-trump'' (preeminent) status for ecological integrity. Electric utility facilities and operations impact biodiversity whenever construction| operation| or maintenance of generation| delivery| and support facilities alters landscapes and habitats and thereby impacts species. Although industry is accustomed to dealing with broad environmental concerns (such as global warming or acid rain)| the biodiversity issue invokes hemisphere-wide| regional| local| and site-specific concerns all at the same time. Industry can proactively address these issues of scope and scale in two main ways: first| by aligning strategically with the broad research agenda put forth by informed scientists and institutions; and second| by supporting focused management processes whose results will contribute incrementally to the broader agenda of rebuilding or maintaining biodiversity. 4245,1996,2,4,Breeding plans in case of global warming,Many cultivated crop plants of temperate and cool temperate zones have during their domestication been transferred far from their original habitats and been distributed over a wide range of climates. In general crop plants seem to possess potential to climatic adaptation. Processes in the past have taken hundreds or thousands of years and over large number of generations. The concern on the velocity of the expected global warming and of subsequent changes in other factors justifies planning of breeding for global warming. Perennial plants| forest trees in particular are more at the focal point than annual plants. Most agricultural annuals may be replaced any year with another cultivar or species better adapted to contemporary circumstances. Trees need tens of years to reach commercial dimensions or fructiferous age. Capriciousness is the main problem of climate change. Large variation of temperature| precipitation among years actually masks the gradual change of average values. The amplitude of variation among years exceeds the predicted average change. Thus| plasticity of individuals besides within population variation in adaptive traits is a corner stone of breeding plans. From the ecological point of view two factors are significant: 1. mild winters may interfere dormancy release and frost tolerance| and also alter host-parasite relationships. 2. The timing of thermal seasons will change in relation to photoperiod. This phenomenon is most prominent in the far north| where the relative warming is largest and the photoperiodic pattern steepest. Even though perennial plants display potential of acclimatization| selection and breeding are eligible measures to improve productivity. As long as the magnitude and velocity of the global warming remain uncertain| it is impossible to set specified aims to breeding. The only reasonable method is to run parallelly several lines with differing patterns of adaptive traits. Multiple population breeding system (MPBS) seems to be tailored to this purpose. 4286,1996,2,4,C-14 dating and soil organic matter dynamics in arctic and subarctic ecosystems,The carbon content| pH and C-14 concentration of humic acids were determined for three soil series of Arctic and Subarctic ecosystems. The measured C-14 ages were interpreted in the light of an equilibrium model of humus formation and of mineralization processes in recent soils| and the coefficient of renovation| K-r| was calculated for humic acids. The comparison of K-r for series formed under different climatic conditions suggested that global warming could accelerate decomposition of soil organic matter and possibly increase productivity of ecosystems of the Arctic region. 4184,1996,3,2,Carbon dioxide production from co-generation for enhanced oil recovery: An economic evaluation,There is a great interest| especially in Western Canada| to capture carbon dioxide (CO2) from fossil fuel fired power plants and utilize it as a flooding agent for enhanced oil recovery (EOR) processes. This concept provides two important benefits: (i) captured CO2 can be utilized as a flooding agent which would generate revenue from incremental oil production| and (ii) CO2 emissions to the atmosphere are reduced| helping to alleviate global warming. In the past few years| a number of feasibility studies and pilot projects on CO2 extraction from power plants have been performed. However| these results have shown that even though it is technically feasible to extract CO2 from power plants| the EOR application cost is high in the current crude petroleum market. A major reason for the high cost is that the CO2 extracting process requires a substantial amount of steam. This paper will demonstrate how cogeneration concepts would help to reduce CO2 production costs by utilizing low-pressure steams and waste heats from various sections of the power generation processes. The economics are based on the installation of a power generation plant and CO2 recovery facility in an existing oil producing facility. 4123,1996,3,4,Carbon dioxide production from coal-fired power plants for enhanced oil recovery: A feasibility study in Western Canada,In order to sustain the current production capacity of conventional oil in Western Canada| enhanced oil recovery (EOR) technologies must be increasingly applied. Among these| CO2 flooding is a highly attractive alternative. A large amount of CO2 is being produced by coal-fired power plants in this region. The CO2 is currently discharged into the atmosphere and could be a major contributor to the greenhouse effect| which may lead to global warming. Thus| the concept of capturing CO2 and utilizing it as a flooding agent in EOR processes is currently generating much interest among oil| utility and coal companies. We demonstrate how cogeneration concepts| together with process-optimization strategies| help to reduce the CO2-production cost by utilizing low-pressure steam and waste heat from various sections of the power-generation process. Based on these concepts and strategies| results from this study show that the recovery cost of CO2 from a coal-fired power plant may range between $0.50 and 2.00/mscf. If the cost is approximately $1.25/mscf| the production cost of a barrel of incremental oil would be less than $18. Therefore| even at today's modest oil prices| there is room for profit to be made operating a CO2 flood with flue-gas-extracted CO2. The technical and economical feasibility of the concepts are evaluated and the practical implications for the Saskatchewan resources are discussed. Copyright (C) 1996 Elsevier Science Ltd. 2490,1996,2,4,Carbon mobilization from the forest floor under red spruce in the northeastern USA,Global climate change may alter soil temperature and moisture conditions| increasing the need to understand how these basic factors affect C dynamics. This is particularly important in boreal forests| which often have large C pools in the forest floor and mineral horizons. We examined the effects of temperature and precipitation frequency on C dynamics in forest floor horizons from eight red spruce sites in the northeastern U.S. using column leaching experiments. Intact and sieved forest floor samples were incubated at 3| 10 or 20 degrees C and leached either daily| once per week| or twice per week during 14 to 39 days using simulated throughfall solutions (pH 2.7 or 4.0). Leachate DOC and CO2 production were measured along with soil C and N concentrations. For intact samples| losses of C as DOC and as CO2 increased with increasing temperature| and the increase (Q(10)) was usually greater between 3 and 10 degrees C than between 10 and 20 degrees C. There was a greater response of CO2 to temperature than of DOC (e.g. Howland sieved soil Q(10)s of 1.9 and 7.2 for CO2 and 1.5 and 2.0 for DOC at 3-10 and 10-20 degrees C ranges| respectively). More frequent leaching increased steady state DOC mobilization (e.g. 145 and 58 mu g g(-1) forest floor d(-1) for daily and weekly leachings at 10 degrees C| respectively)| but not CO2 evolution (e.g. 79 and 74 mu g CO2-C g(-1) forest floor d(-1) for daily and weekly leachings at 10 degrees C| respectively). Across the eight sites DOC loss and CO2 evolution varied by factors of 3.6 and 4.0| respectively. Both CO2 evolution and DOC in leachates calculated as fluxes were correlated (r = 0.73 and 0.87 respectively| n = 8) with the C-to-N ratios of the samples (C-to-N ratios ranged from 27 to 58)| which could be explained by N limitations that triggered selective lignin degradation| differences in degree of humification of the material| or position on a west-to-east pollution gradient. Although higher temperatures and more frequent leaching increased DOC mobilization| and higher temperatures increased CO? evolution| both treatments and site to site variation illustrate the complexity of the response of forest-floor C pools to manipulations. Copyright (C) 1996 Elsevier Science Ltd 4247,1996,4,3,Carbon uptake by secondary forests in Brazilian Amazonia,Estimating the contribution of deforestation to greenhouse gas emissions requires calculations of the uptake of carbon by the vegetation that replaces the forest| as well as the emissions from burning and decay of forest biomass and from altered emissions and uptakes by the soil. The role of regeneration in offsetting emissions from deforestation in the Brazilian Legal Amazon has sometimes been exaggerated. Unlike many other tropical areas| cattle pasture (rather than shifting cultivation) usually replaces forest in Brazilian Amazonia. Degraded cattle pastures regenerate secondary forests more slowly than do fallows in shifting cultivation systems| leading to lower uptake of carbon. The calculations presented here indicate that in 1990 the 410 X 10(3) km(2) deforested landscape was taking up 29 X 10(6) t of carbon (C) annually (0.7 t C ha(-1) year(-1)). This does not include the emissions from clearing of secondary forests| which in 1990 released an estimated 27 X 10(6) t C| almost completely offsetting the uptake from the landscape. Were the present land-use change processes to continue| carbon uptake would rise to 365 X 10(6) t annually (0.9 t C ha(-1) year(-1)) in 2090 in the 3.9 X 10(6) km(2) area that would have been deforested by that year. The 1990 rate of emissions from deforestation in the region greatly exceeded the uptake from regrowth of replacement vegetation. 4268,1996,2,2,Carbon use in root respiration as affected by elevated atmospheric O-2,The use of fossil fuel is predicted to cause an increase of the atmospheric CO2 concentration| which will affect the global pattern of temperature and precipitation. It is therefore essential to incorporate effects of temperature and water supply on the carbon requirement for root respiration of plants to predict effects of elevated [CO2] on the carbon budget of natural and managed systems. There is insufficient information to support the contentention that an increase in the concentration of CO2 in the atmosphere will enhance the CO2 concentration in the soil to an extent that is likely to affect root respiration. Moreover| there is no convincing evidence for a direct effect of elevated atmospheric [CO2] on the rate of root respiration per unit root mass or the fraction of carbon required for root respiration. However| there are likely to be indirect effects of elevated [CO2] on the carbon requirement of plants in natural systems. Firstly| it is very likely that the carbon requirement of root respiration relative to that fixed in photosynthesis will increase when elevated [CO2] induces a decrease in nutrient status of the plants. Although earlier papers have emphasized that elevated [CO2] favours investment of biomass in roots relative to that in leaves| these are in fact indirect effects. The increase in root weight ratio is due to the more rapid depletion of nutrients in the root environment as a consequence of enhanced growth. This will decrease the specific rate of root respiration| but increase the carbon requirement as a fraction of the carbon fixed in photosynthesis. It is likely that these effects will be minor in systems where the nutrient supply is very high| e.g| in many managed arable systems| and increase with decreasing soil fertility| i.e. in many natural systems. Secondly| a decrease in rainfall in some parts of the world may cause a shortage in water supply which favours the carbon partitioning to roots. Water stress is likely to reduce rates of root respiration per unit root mass| but enhance the fraction of total assimilates required for root respiration| due to greater allocation of biomass to roots. Increased temperatures are unlikely to affect the specific rate of root respiration in all species. Broadly generalized| the effect of temperature on biomass allocation is that the relative investment of biomass in roots is lowest at a certain optimum temperature and increases at both higher and lower temperatures. The root respiration of some species acclimates to growth temperature| so that the effect of global temperature rise is entirely accounted for by the effect of temperature on biomass allocation. The specific rate of root respiration of other species will increase with global warming. In response to global warming the carbon requirement of roots is likely to decrease in temperate regions| when temperatures are suboptimal for the roots' capacity to acquire water. Here global warming will induce a smaller biomass allocation to the roots. Conversely| the carbon requirements are more likely to increase in mediterranean environments| where temperatures are often supraoptimal and a rise in temperature will induce greater allocation of biomass to the roots. 4241,1996,2,2,Changing probabilities of daily temperature extremes in the UK related to future global warming and changes in climate variability,The impacts of 2 greenhouse gas emissions scenarios (one from the IPCC and one from Greenpeace International) on the occurrence of extreme daily temperature events are considered at several sites in the UK. For each site| a number of probability distributions were tested for goodness-of-fit to 1961-87 observed daily maximum and minimum temperature data using the Kolmogorov-Smirnov lest. The parameters of the best-fitting distributions were then perturbed to take into account climate change| both mean and variability. Probabilities of the occurrence of particular temperature threshold events were calculated for both present and future climates. Changes in climate variability were considered in 3 ways: (1) by assuming the present variance stays the same in the future; (2) by imposing standardised percent changes in variance; and (3) by imposing variance changes derived from the UK Meteorological Office high resolution GCM equilibrium climate change experiment. Results presented for 2 contrasting sites illustrate the importance of including changes in variability in climate change studies. Specific results depend on the site and threshold temperature chosen and on the distribution characteristics. However| for example| at Fortrose the 1961-87 mean maximum temperature in July is below 20 degrees C. With increases in global-mean temperature| the probability of this threshold being exceeded increases| although the rate of increase depends on the variance change being considered. The largest rate of increase in probability occurs with a 20% per degrees C increase in variance. The approach described here has been used in one component of a climate change scenario generator for the UK developed for the UK Ministry of Agriculture| Fisheries and Food. 4230,1996,2,4,Climate change impacts on US commercial building energy consumption: An analysis using sample survey data,Although much of the commercial sector infrastructure for the next century is currently under construction or is in the planning stages| little has been done in communicating how potential global warming might change the energy consumption characteristics of the building stock. The research discussed in this article advances the literature on how climate change affects commercial sector energy demand systems. It projects the effects of climate change on commercial energy demand in the United States at the national level. The article relies heavily on time-series regressions of monthly energy consumption by building on monthly heating and cooling degree days. It provides empirical results for the effects of climate on a projected building stock in the year 2030 and examines the prospects for saving energy with advanced building designs in the context of potential global warming. 2485,1996,2,3,Climate change in Asia: A review of the vulnerability and adaptation of crop production,A number of studies have provided quantitative assessments of the potential climate change impacts on crop production in Asia. Estimates take into account (a) uncertainty in the level of climate change expected| using a range of climate change scenarios; (b) physiological effects of carbon dioxide on the crops; and (c) different adaptive responses. In all cases| the effects of climate change induced by increased atmospheric carbon dioxide depended on the counteracting effects among higher daily evapotranspiration rates| shortening of crop growth duration| and changes in precipitation patterns| as well as the effects of carbon dioxide on crop growth and water-use efficiency. Although results varied depending on the geographical locations of the regions tested| the production of rice (the main food crop in the region) generally did not benefit from climate change. In South and Southeast Asia| there is concern about how climate change may affect El Nino/Southern Oscillation events| since these play a key role in determining agricultural production. Furthermore| problems arising from variability of water availability and soil degradation are currently major challenges to agriculture in the region. These problems may be exacerbated in the future if global climate change projections are realized. Many studies have considered strategies for improving agricultural management| based on the optimization of crop management decisions. Climate change analyses could be further strengthened by economic studies that integrate the potential use of natural resources across sectors. 2477,1996,2,4,Climate change| water stress| and fast forest response: A sensitivity study,Environmental crises provide ecology with a new impetus. Indeed| acid rain| massive changes in land-use| and the prospect of global climate change are giving the study of ecosystems a new meaning and new mandates. Careful natural history descriptions are no longer sufficient for evaluating potential impacts of changing environmental conditions. Understanding how ecosystems work has become a priority. The present paper investigates the role of water stress as an agent of rapid vegetation change. A sensitivity study is performed to explore the issue. Environmental changes are imposed| rather than obtained from atmospheric general circulation model (GCM) output| to facilitate the interpretation of the results| to enable the identification of generic patterns| in particular| critical thresholds| and to foster the understanding of underlying processes. A physically- and physiologically-based| climatically-sensitive| numerical simulation model of forest dynamics| the Energy| Water| and Momentum Exchange and Ecological Dynamics (EXE) model| is used for this purpose. The results of the sensitivity analysis undertaken with EXE document the interplay between physical and physiological feedbacks and ecological forest responses to climatic changes. Moreover| they explain the relative importance of temperature| water| and nitrogen limitations| indicating that water stress is responsible for some of the fastest vegetation changes. 4095,1996,2,3,Climatic effect of water vapor release in the upper troposphere,Water vapor is released into the Goddard Institute for Space Studies (GISS) global climate middle atmosphere model at the locations and cruise altitude of subsonic aircraft. A range of water vapor values is used to simulate not only current and 2015 projected emissions but also to provide larger signal-noise ratios. The results show that aircraft water vapor emissions do not significantly affect the model's climate| either at the surface or in situ. With emissions some 15 times higher than the 2015 projection| a small impact is observed| amounting to a few tenths degrees celsius globally and locally| while with emissions 300 times the 2015 values| a global warming of 1 degrees C results. However| with releases this large| only about 5% actually stays in the atmosphere. The larger emissions increase the specific humidity most in the tropical lower troposphere| partly as a result of increased evaporation due to the global warming; at flight altitudes| relative humidity and cloud cover increase at latitudes of emission| and temperature decreases. Surface warming is relatively independent of latitude| and only a slight longitudinal aircraft footprint is found in the warming for the most extreme experiment. Comparison to increased CO2 experiments of similar magnitude warming shows that the upper tropospheric response is greater in the water vapor release experiments| but the high-latitude surface temperature response is larger with increased CO2 due to more effective cryospheric feedbacks. 4149,1996,2,3,Climatic trends from isotopic records of tree rings: The past 100-200 years,There has been a great deal of discussion about global warming from accumulation of anthropogenic greenhouse gases in the atmosphere (Houghton et al.| 1990). Relatively less attention has been paid to spatial and/or temporal climatic variations that may be associated with a warmer climate (Rind et al.| 1989) or with anthropogenic activities (Schneider| 1994). In this article; we show that an increase in climatic variability may have started. Fourteen isotopic time series of tree rings are presented. These trees were randomly collected from world-wide locations and cover time periods of 120 to over 200 years. The isotopic records show increasing delta D values that suggest a consistent and progressive warming occurred in the 19th century in all locations where the trees were sampled. The rate of warming is greater at relatively cold locations than at warm locations with two exceptions. The records also suggest greater climatic variations both temporally and spatially in the 20th century than in the 19th century. 4117,1996,2,4,Climatic warming and the degradation of warm permafrost,Permafrost - a widespread constituent of the terrestrial environment - by definition is dependent upon the ambient temperature for its existence and properties. Thus| it is very sensitive to climatic changes. Simple relations based upon conductive heat transfer| with thawing and geothermal heat flow| are presented to predict the transient effects of surface temperature increases on the thermal state of permafrost. The results indicate that| based on the usual global warming scenarios| relatively small amounts of permafrost will disappear within 50-100 years. This is specifically shown for the most thermally sensitive cases| that is| warm or relict permafrost.
4196,1996,4,4,Coal fuel cycle externalities estimates (part of the US initiative of the US DOE/CEC study),Electricity is of considerable benefit to the consumer and society. However| the price paid by the consumer does not necessarily reflect the full cost. There are two components to the full cost. One component is the private costs that are paid by the consumer| such as labor| capital| fuel| insurance| etc. The other component includes the cost or benefit accrued to third parties| such as: effects of global warming potential; effects on health from the emissions of SO2| NOx| and particulates; and other considerations. These costs or benefits are termed externalities| and usually are not included in the price paid by the consumer. Externalities estimates are presented for site-specific Pulverized Fuel electric generation stations located in the southwestern and southeastern part of the U.S.A. The results are referenced to the specific location and may not be applicable to other sites or technologies. The externalities are discussed for a wide range of effects| from global warming potential through trace metal emissions to energy security. 2496,1996,2,4,Comparison of sap flow| cavitation and water status of Quercus petraea and Quercus cerris trees with special reference to computer tomography,Concurrent measurements of sap velocity (heat pulse) and ultrasound acoustic emission were performed on the trunks of mature Turkey oak (Quercus cerris) and sessile oak (Quercus petraea) trees| Plant water status was assessed by measuring leaf water potential| leaf conductance and transpiration| Wood density was estimated non-destructively on the trunk section of the plants by mobile computer tomography| which measures the attenuation of a collimated beam of radiation traversing the trunk in several directions| as the device rotates around the tree| Absorption is proportional to the density of the wood| As wood density is strictly correlated to water content| this non-invasive method allows the water content in the trunk section to be evaluated as well as mapped. Leaf water potential declined each morning until a minimum was reached at midday and recovered in the afternoon| lagging behind changes in transpiration rate| Good correspondence was found between the patterns of sap velocity and cavitation rate| A close correlation was demonstrated between wood density| mater content and sap velocity| Sap flow was always higher in Turkey oak than in sessile oak| Trunk signatures by computer tomography appeared to differentiate the two oak species| with the Turkey oak stem clearly more hydrated than the sessile oak; water storage reservoirs could play an important role in tree survival during extended periods of low soil water availability and in the relative distribution of tree species| especially in the context of global climate change. Late-wood conducting elements of oak species seem to play a significant role in water transport| The mobile computer tomograph was confirmed as a peerless tool for investigating stem water relations| Diurnal variations in the measured parameters under natural drought conditions and the differences between the two oak species are discussed. 4134,1996,3,3,Control of rumen methanogenesis,During the last decades| considerable research on methane production in the rumen and its inhibition has been carried out. Initially| as methane production represents a significant loss of gross energy in the feed (2-15%)| the ultimate goal of such intervention in rumen fermentation was an increase in feed efficiency. A second reason favouring research on methane inhibition is its role in the global warming phenomenon and in the destruction of the ozone layer. In this review| the authors describe briefly several interventions for reducing methane emission by ruminants. The objective can be reached by intervention at the dietary level by ration manipulation (composition| feeding level) or by the use of additives or supplements. Examples of additives are polyhalogenated compounds| ionophores and other antibiotics. Supplementation of the ration with lipids also lowered methanogenesis. More biotechnological interventions| e.g.| defaunation| probiotics and introduction of reductive acetogenesis in the rumen| are also mentioned. It can be concluded that drastic inhibition of methane production is not unequivocally successful as a result of several factors| such as: instantaneous inhibition often followed by restoration of methanogenesis due to adaptation of the microbes or degradation of the additive| toxicity for the host animal| negative effects on overall digestion and productive performance. Therefore| methanogenesis and its inhibition cannot be considered as a separate part of rumen fermentation and its consequences on the animal should be taken into account. 2504,1996,2,3,Controls on CH4 flux from an Alaskan boreal wetland,Factors controlling the flux of the radiatively important trace gas methane (CH4) from boreal wetlands were examined at three sites along a moisture gradient from a treed low-shrub bog to an open floating graminoid bog in Fairbanks| Alaska. In the summer of 1992 average static chamber flux measurements were -0.02| 71.5| and 289 mg CH4/m(2)/d in dry| wet| and floating mat communities| respectively. In contrast| the warmer| drier 1993 field season flux measurements were -0.02| 42.9 and 407 mg CH4/m(2)/d. The data indicate that despite net oxidation of CH4 in the dry regions of the bog| the wetland is a net source of CH4| with fluxes ranging across three orders of magnitude between different plant communities. Comparison with water levels suggests that CH4 flux is turned on and off by changes in site hydrology. In sites where sufficient moisture is present for methanogenesis to occur| CH4 flux appears to be temperature limited| responding exponentially to soil temperature changes. The combined effects of hydrology and temperature create hot spots of CH4 flux within boreal wetlands. The plant communities within Lemeta Bog respond differently to changes in temperature and moisture availability| creating both positive and negative feedbacks to potential global climate change. 4185,1996,3,3,Converting terrestrial ecosystems from sources to sinks of carbon,It may be possible to sequester carbon in forests and forest products| but to date global trends in land management have resulted in a release of terrestrial carbon to the atmosphere. Over 100 PgC were released between 1850 and 1980| and during the 1980s global changes in land use (predominantly deforestation) caused a net release of 1.6 PgC yr(-1)| about 25% of the total emissions of carbon dioxide from human activities and about 15% of the enhanced radiative forcing. Management practices that could change this release of terrestrial carbon to an accumulation include (i) a halt to deforestation; (ii) an expansion in the land area of forests; (iii) an increase in the stocks of carbon in existing forests; (iv) more efficient harvest and greater use of wood in long-lasting products; and (v) the substitution of wood fuels for fossil fuels. However| the rate of global warming needs management as well. Unless the warming is gradual enough to avoid widespread mortality of forests| the additional releases of carbon caused by the warming itself| through increased respiration| decay| and fires| may cancel the intended effects of forest management. 4124,1996,2,4,Correlation between egg size and clutch size in the Pied Flycatcher Ficedula hypoleuca in cold and warm summers,The correlation between egg size and clutch size was studied in the Pied Flycatcher Ficedula hypoleuca in Finnish Lapland from 1975 to 1994. The hypothesis tested was that the tradeoff phenomenon is masked by warm weather. When data for 20 years were pooled| there was no correlation| However| when years were analysed separately| a negative correlation was observed for five of the years| Over 12 years| the correlation coefficient between egg size and clutch size was not significant| and for 3 years it was significantly positive. The size and magnitude of the correlation were related to temperature during the pre-laying and egg-laying periods| Of the annual variation| 34% was explained by the mean temperature in early summer. It is suggested that trade-off between egg size and clutch size may not be apparent in central (southern) parts of the distribution area of the species where climate is warmer. In the future| global warming may alter reproductive strategies of birds. Long-term data may thus be useful in the analysis of such effects and in testing of theoretical questions in ecology. 2512,1996,2,4,Cross-scale relationships regarding local temperature inversions at Cape Town and global climate change implications,This study develops a downscaling methodology for establishing relationships between Cape Town's winter synoptic scale circulation and temperature inversions in the boundary layer Application lion of the method is demonstrated by deriving inversion frequencies from general circulation model (GCM) data sets. Daily midday radiosonde data at Cape Town International airport for the winter of 1989 were classified in a binary manner for the identification of temperature inversions| and an artificial neural network (ANN) was trained to relate sea-level pressure fields over Cape Town to local inversion conditions. ANNs were used to derive the relationships because of their robustness in the presence of noise and because they| do not have the constraints of linearity. These relationships were then applied to the simulations generated by two GCMs| the GISS and GENESIS models| in order to investigate their ability to represent the synoptic controls on local inversions. The two GCMs compared favourably with each other and were reasonably similar to the NMC's observational data regarding the number of temperature inversions each reflected. Following this| circulation for a simulation of doubled atmospheric CO2 was used to predict possible future changes in the frequency of inversions over Cape Town. The occurrence of temperature inversions increased by approximately 25% using the GISS model and by 33% using GENESIS. This putative increase in inversion frequency as a result of global climate change could have implications for the city's atmospheric pollution. 2467,1996,4,4,Detecting discontinuities in time series of upper-air data: Development and demonstration of an adaptive filter technique,Recognizing the need for a long-term database to address the problem of global climate change| the National Climatic Data Center has embarked on a project called the Comprehensive Aerological Reference Data Set to create an upper-air database consisting of radiosondes| pibals| surface reports| and station histories for the Northern and Southern Hemispheres. Unfortunately| these data contain systematic errors caused by changes in instruments| data acquisition procedures| etc. It is essential that systematic errors be identified and/or removed before these data can be used confidently in the context of greenhouse-gas-induced climate modification. The purpose of this paper is to illustrate the use of an adaptive moving average filter in detecting systematic biases and to compare its performance with the Schwarz criterion| a parametric method. The advantage of the adaptive filter over traditional parametric methods is that it is less affected by seasonal patterns and trends. The filter has been applied to upper air relative humidity and temperature data. The accuracy of locating the time at which a bias is introduced ranges from about 600 days for Changes of 0.1 standard deviations to about 20 days for changes of 0.5 standard deviations. 2492,1996,3,3,Development of a risk-hedging CO2-emission policy .2. Risks associated with measures to limit emissions| synthesis| and conclusions,This paper is Part II of a two-part series in which the risks associated with unrestrained greenhouse-gas emissions| and with measures to limit emissions| are reviewed. A sustained limitation of global CO2 emissions requires global population stabilization| a reduction in per capita emissions in the developed world| and a limitation of the increase in per capita emissions in the developing world. Reducing or limiting per capita emissions requires a major effort to improve the efficiency with which energy is transformed and used; urban development which minimizes the need for the private automobile and facilitates district heating| cooling| and cogeneration systems; and accelerated development of renewable energy. The following risks associated with these efforts to limit CO2 emissions are reviewed here: (i) resources might be diverted from other urgent needs; (ii) economic growth might be reduced; (iii) reduction measures might cost more than expected; (iv) early action might cost more than later action; (v) reduction measures might have undesired side effects; (vi) reduction measures might require heavy-handed government intervention; and (vii) reduction measures might not work. With gradual implementation of a diversified portfolio of measures| these risks can be greatly reduced. Net risk is further reduced by the fact that a number of non-climatic benefits would result from measures to limit CO2 emissions. Based on the review of risks associated with measures to limit emissions here| and the review of the risks associated with unrestrained emissions presented in Part I| it is concluded that a reasonable near-term (20-30 year) risk hedging strategy is one which seeks to stabilize global fossil CO2 emissions at the present (early 1990's) level. This in turn implies an emission reduction of 26% for industrialized countries as a whole and 40-50% for Canada and the USA if developing country emissions are to increase by no more than 60%| which in itself would require major assistance from the industrialized countries. The effectiveness of global CO2-emission stabilization in slowing down the buildup of atmospheric CO2 is enhanced by the fact that the airborne fraction (ratio of annual atmospheric CO2 increase to total annual anthropogenic emissions) decreases if emissions are stabilized| whereas it increases if emissions continue to grow exponentially. The framework and conclusions presented here are critically compared with so-called optimization frameworks. 4260,1996,2,4,Development of a water temperature-ecological model to stimulate global warming effects on lake ecosystem,This paper describes a newly developed combined water temperature-ecological (WT-ECO) model which is employed to simulate the effects of global warming on lake and reservoir ecosystems. The WT model includes (i) variations in the eddy diffusion coefficient based on the degree of thermal stratification and the velocity of wind| and (ii) a sub-model for simulating the freezing and thawing processes of surface water| water temperatures| and the mixing rates between two adjacent layers of water. The ECO model then uses these results to calculate the resultant effect on a lake's ecological dynamics| e.g.| composition of phytoplankton species| their respective concentrations| and nutrient concentrations| When the model was benchmarked against Lake Yunoko| a dimictic lake| fairly good agreement was obtained over a 4-yr period; thereby indicating it is suitably calibrated. In addition| to assess the effects of global warming on a lake ecosystem| changes in Lake Yunoko's water temperature/quality were simulated in response to an increase in air temperature of 2-4 degrees C. Results indicate that such an increase will (i) increase thermal stratification in summer| which increases the nutrient concentrations in bottom water due to nutrient release from bottom sediment| (ii) increase the concentration of phytoplankton at the beginning of the autumn circulation period| and (iii) change the composition of phytoplankton species. Copyright (C) 1996 IAWQ. 2518,1996,2,3,Differential responses of root uptake kinetics of NH4+ and NO3- to enriched atmospheric CO2 concentration in field-grown loblolly pine,The nitrogen requirement of plants is predominantly supplied by NH4+ and/or NO3- from the soil solution| but the energetic cost of uptake and assimilation is generally higher for NO3- than for NH4+. We found that CO2 enrichment of the atmosphere enhanced the root uptake capacity for NO3-| but not for NH4+| in field-grown loblolly pine saplings. Increased preference for NO3- at the elevated CO2 concentration was accompanied by increased carbohydrate levels in roots. The results have important implications for the potential consequences of global climate change on plant- and ecosystem-level processes in many temperate forest ecosystems. 4112,1996,3,3,Discounting and distributional considerations in the context of global warming,The economics of global warming is reviewed with special emphasis on how the cost depends on the discount rate and on how costs in poor and rich regions are aggregated into a global cost estimate. Both of these factors depend on the assumptions made concerning the underlying utility and welfare functions. It is common to aggregate welfare gains and losses across generations and countries as if the utility of money were constant| but it is not. If we assume that a CO2-equivalent doubling implies costs equal to 1.5% of the income in both high and low income countries| a pure rate of time preference equal to zero| and a utility function which is logarithmic in income| then the marginal cost of CO2 emissions is estimated at 260-590 USD/ton C for a time horizon in the range 300-1000 years| an estimate which is large enough to justify significant reductions of CO2 emissions on purely economic grounds. The estimate is approximately 50-100-times larger than the estimate made by Nordhaus in his DICE model and the difference is almost completely due to the choice of discount rate and the weight given to the costs in the developing world as well as a more accurate model of the carbon cycle| Finally| the sensitivity of the marginal cost estimate with respect to several parameters is analyzed. 4189,1996,3,4,Discounting of long-term costs: What would future generations prefer us to do?,Decisions with intergenerational consequences may leave future generations worse off (i.e.| not be Pareto-optimal) if costs and benefits are not discounted correctly. We point out that this happens if the conventional social discount rate is applied to intergenerational costs: with that rate the justification of intergenerational costs (benefits of a project are invested and the proceeds can cover future costs) leads to an inconsistency over the long term (eventually the supposed benefits of any project become larger than the entire GNP). The conventional approach commits an error by treating the time preference component of the discount rate as if it represented creation of wealth while it really involves only redistribution. The time horizon of the redistribution is limited by the duration of market transactions| especially loans. Thus we recommend a two-step discounting procedure| with the conventional social discount rate for the shea term (about 30 years) and the growth rate of the economy for the long term. Data for GNP per capita growth in the US| the UK| France| Germany| Japan and the Soviet Union since the industrial revolution| combined with data for net economic welfare per capita suggest an intergenerational discount rate in the range of 1 to 2%. For practical application the rate at which costs and benefits will grow over time is just as important as the discount rate; only the difference between these two rates matters. For many environmental costs these rates may be close to each other during the next few generations; this implies that some of the uncertainty in the prediction of rates cancels and one can treat the problem as if the effective rate were close to zero. The consequence for costs such as global warming or nuclear power can be very significant: the valuation can increase by more than an order of magnitude compared to values based on conventional discounting. 2531,1996,3,4,District heating & cooling systems of the future: Strategies for global change,The future of district heating and cooling| also known as district energy| will be a function of economic and regulatory forces in the United States. Typically a district energy system provides thermal energy in the form of steam| hot water| or chilled water from a central plant| and distributes the energy through pipes to two or more buildings. At the present time| district energy is under-utilized and serves only 1.3 percent of U.S. energy needs| providing a total of 1.1 quadrillion Btu of energy annually. A brief review of the historical development of district energy| the status of the technology in the United States| and a few basics on world energy consumption lead in to the economic and environmental advantages of district energy. District energy systems have been retrofitted to comply with the regulations of the Clean Air Act (CAA); presently emissions of greenhouse gases| such as CO2| are not regulated by the CAA. If the results of ongoing investigation on global climate change determine that regulation is warranted| several strategies exist for district energy systems to offer significant reductions in greenhouse gas emissions. Projections of district energy's reaction to the ongoing forces are possible with the use of energy consumption forecasts through the year 2015| and a discussion of trend setting concepts being applied involving. gas turbines| cogeneration| fuel cells| chillers| advanced transmission fluids| renewable energies| and CO2 capture. District energy has potential to be an important part of the evolving strategies for global climate change. For this reason| combined with technology advancements and a supportive economic climate| a new era in district energy has begun. Growth and development of district energy into the foreseeable future is expected to be strong. 2529,1996,2,4,Downscaling two versions of a general circulation model to estimate local hydroclimatic factors under climate change,The regional hydroclimatological effect of global climate change has been estimated and compared using a semi-empirical downscaling method with two versions (T21 and T42) of the general circulation model (GCM) developed at the Max Planck Institute for Meteorology| Germany. The comparisons were performed with daily mean temperature and daily precipitation amounts for the continental climate of the state of Nebraska| USA. Both the T21 and the T42 versions resulted in an increase of daily mean temperature under a 2 x CO2 climate. The magnitude of warming was substantially greater for T21 than for T42| except for February and June and at some stations in July where the T42 model suggested greater warming. Both GCMs resulted in a slight decrease in precipitation frequency and an increase in the amount of precipitation on wet days. Here| the T42 model again led to smaller changes. Different locations within Nebraska exhibited somewhat different temperature and precipitation responses with both GCM versions. 4194,1996,3,3,Economic implications and decision-making in the face of global warming,One way to approach decision-making on the issue of global warming is to attempt to perform a cost-benefit analysis. However an this issue problems of valuation| risk and uncertainty| time-discounting| and equity make cost-benefit analysis so inconclusive and controversial that-far from helping decision-making-it is likely to hinder it. An alternative approach involves accepting that climate stability has to be secured on the grounds of environmental sustainability| and determining in principle to undertake the abatement of greenhouse gas emissions that is necessary to achieve this. The timetable of such abatement will obviously depend to some extent on its costs. The evidence on abatement costs suggests that a 20 percent abatement from 1990 levels of carbon dioxide (the principal greenhouse gas) can be achieved in industrial countries at low or no cost by 2010. Application of the sustainability principle suggests that this is a reasonable first target. If deeper cuts in emissions are deemed necessary thereafter they will be achieved more easily and at lower cost than if abatement in the interim is negligible. 4221,1996,4,3,Economics| ethics| and climate policy: Framing the debate,This paper examines the economic and ethical dimensions of climate policy in light of existing knowledge of the impacts of global warming and the costs of greenhouse gas emissions abatement. We find that the criterion of economic efficiency| operationalized through cost-benefit analysis| is ill-equipped to cope with the pervasive uncertainties and issues of intergenerational fairness that characterize climate change. In contrast| the concept of sustainable development-that today's policies should ensure that future generations enjoy life opportunities undiminished relative to the present-is a normative criterion that explicitly addresses the uncertainties and distributional aspects of global environmental change. If one interprets the sustainability criterion to imply that it is morally wrong to impose catastrophic risks on unborn generations when reducing those risks would not noticeably diminish the quality of life of existing persons| a case can be made for significant steps to reduce greenhouse gas emissions. 4254,1996,2,4,Ecotypic differences in the flowering of Pimelea ferruginea (Thymelaeaceae) in response to cool temperatures,Pimelea ferruginea Labill.| a spring-flowering woody perennial from Western Australia| is distributed coastally from Albany (latitude 35 degrees 11'S) to just below Geraldton (latitude 29 degrees 07'S). Clones developed from cuttings| taken from single plants of Pimelea ferruginea at sites covering the range of its distribution| were grown vegetatively for up to 6 months in a naturally lit glasshouse and then transferred to a range of temperatures for induction of flowering. Selections from cooler| southerly sites (33-35 degrees S latitude) flowered with a low temperature optimum (12-15 degrees C average) but remained vegetative at a 3 degrees C higher temperature (18 degrees C). By contrast| northerly selections (29-30 degrees S latitude) tolerated 3-5 degrees C warmer conditions for their flowering. Daylength effects were of minor importance relative to the response to cool temperature with short (10 h) days being marginally more favourable than long days (16 h). In the wild| Pimelea ferruginea flowers in spring (September-October) after experiencing winter temperatures comparable to those effective in controlled environments. To define field flowering response| at the beginning of winter| vegetative six-month-old plants of the various selections were transferred to a southerly| intermediate or northerly field nursery site in Western Australia. The differences in flowering response across sites and selections broadly matched the temperatures needed for flowering of the selections in controlled environments. These physiological differences in regulation of flowering indicate ecotypic adaptation to temperature over the latitudinal range of distribution of this species of Pimelea. The field transfer experiments highlight the overriding inductive effect of cool winter temperatures in determining flowering time. Furthermore| any rise of 2-4 degrees C in winter temperature due to global warming could have serious consequences for floral initiation and for survival of P. ferruginea. 2507,1996,2,3,Effect of changing temperature and water table on trace gas emission from minerotrophic mires,Peatlands| hydromorphous soils with high organic matter content| display| as a result of anaerobic conditions| a delayed litter decomposition and therefore constitute important terrestric sinks for carbon and nitrogen compounds. In spite of their relatively small area proportion of approx. 3% (3.88-4.38 x 10(6) km(2))| peatlands contain approx. 30% of the world's soil carbon and nitrogen reserves. Several signs indicate that substantial drainage and increasing temperatures due to the increasing cultivation of peatlands and the global climate change could result in a large-scale conversion of peatlands from C/N sinks to C/N sources. Irrespective of many uncertain details and complex interactions with other factors| the lowering of the groundwater table of peatlands actually seems to strongly enhance the net release of the radiatively active trace gases carbon dioxide and nitrous oxide| reducing at the same time the high emissions of methane that occur in natural peatlands. The antizipated climate change will probably induce large-scale shifts in the distribution of the different peatland ecosystems along with considerable changes of the trace gas emissions. In view of this development| a net loss of global peatland area along with an increase in their contribution to the greenhouse effect must be expected. 4276,1996,3,4,Effect of forest drainage on the carbon balance of a mire: A case study,Natural mires generally act as sinks for CO2 and are sources of CH4 for the atmosphere. However| drainage may transform these ecosystems into net sources of CO2| but the increase in growth of the tree stand and consequent fixation of carbon after drainage may be expected to have a compensating effect. The post-drainage change in the peat carbon stores was determined using a method based on the bulk density and carbon content profiles measured along a transect running from the undrained part to the drained part of the mire. The difference between the undrained and drained peat carbon stores| averaged over the 30 yr period after drainage| indicated that the accumulation of carbon had been 35 g C m(-2) yr(-1) greater in the undrained site. As the long-term accumulation rate of the undrained site had been 21 g C m(-2) yr(-1)| the drained part had lost 14 g C m(-2) yr(-1) from the pre-drainage carbon store. Total accumulated biomass in the tree stand was estimated from stem wood development using the growth and yield tables for this site type. The stem wood volumes were transformed into total biomass values using published stem-volume/total-biomass ratios. If no harvesting operations were to occur during the first 300 yrs| the tree stand would produce an average carbon store of approximately 11 kg C m(-2). The application of a standard thinning regime would reduce this storage by ca 50%. Expressed as an average over 300 yrs| drainage increased the total carbon store of the mire if no tree harvesting was done and the store remained unchanged if standard harvesting procedures were used. 4273,1996,4,4,Effects of alternative cloud radiation parameterizations in a general circulation model,Using the National Center for Atmospheric Research (MCAR) general circulation model (CCM2)| a suite of alternative cloud radiation parameterizations has been tested. Our methodology relies on perpetual July integrations driven by +/-2 K sea surface temperature forcing. The tested parameterizations include relative humidity based clouds and versions of schemes involving a prognostic cloud water budget. We are especially interested in testing the effect of cloud optical thickness feedbacks on global climate sensitivity. All schemes exhibit negative cloud radiation feedbacks| i.e.| cloud moderates the global warming. However| these negative net cloud radiation feedbacks consist of quite different shortwave and longwave components between a scheme with interactive cloud radiative properties and several schemes with specified cloud water paths. An increase in cloud water content in the warmer climate leads to optically thicker middle- and low-level clouds and in turn negative shortwave feedbacks for the interactive radiative scheme| while a decrease in cloud amount leads to a positive shortwave feedback for the other schemes. For the longwave feedbacks| a decrease in high effective cloudiness for the schemes without interactive radiative properties leads to a negative feedback| while no distinct changes in effective high cloudiness and the resulting feedback are exhibited for the scheme with interactive radiative properties. The resulting magnitude of negative net cloud radiation feed-back is largest for the scheme with interactive radiative properties. Even though the simulated values of cloud radiative forcing for the present climate using this method differ most from the observational data| the approach shows great promise for the future. 4161,1996,2,4,Effects of changes in minimum and maximum temperature on wheat yields in the central US - A simulation study,Recent observations and general circulation models indicate that future temperature changes linked to global warming might be characterized by a marked asymmetry between daytime maxima and nighttime minima. We investigate the importance of such a pattern in determining future wheat (Triticum aestivum) yields in the Central United States by using a dynamic crop growth model| CERES-Wheat| modified to include physiological effects of temperature and CO2 on canopy photosynthesis. Simulations are run at four sites spanning a north-south transect of the Central US; four mean temperatures increases (1-4 degrees C) are applied to baseline daily climate data (1951-1980). The effects of two different scenarios of temperature change (minimum and maximum temperatures equally raised; minima increased three times as much as maxima in agreement with recent observations) are analyzed under both current (330 ppm) and elevated (550 ppm) CO2 concentrations. The main mechanisms controlling the simulated wheat responses are direct and indirect temperature effects on wheat phenological development. Negative effects of temperature on simulated wheat yields are reduced when minima increase more than maxima. Yield changes are consistently negative under temperature change and current CO2 concentration| while they range from positive to negative under temperature change and elevated CO2 concentration. Responses vary across the transect| with larger negative effects occurring at the southernmost site. 4261,1996,2,4,Effects of CO2 concentration on the photosynthetic and carboxylation efficiencies of Fagus crenata and Quercus crispula,To determine the effects of limited and elevated CO2 concentrations on leaf photosynthesis which may suggest the effects of global CO2 level increase and global warming on forest structure| the photosynthetic and carboxylation efficiencies were investigated in two representative co-occurring tree species in the cool-temperate natural forests in central Japan| Fagus crenata and Quercus crispula. Measurements were performed for four-year-old seedlings in CO2-air mixtures of 175| 350| 700 and 900 mu mol mol(-1)| respectively| with photosynthetic irradiance (I) decreasing gradually from 1200 mu mol m(-2) s(-1) to darkness| and at 25 +/- 0.2 degrees C leaf temperature and 1.8 +/- 0.2 kPa leaf to air vapour pressure deficit. The CO2 concentrations strongly stimulated net photosynthetic rate| P-N (p<0.001)| and the photosynthetic efficiency| alpha| for both F. crenata and Q. crispula. Carboxylation efficiency of Q. crispula was dependent on I| with a significantly higher efficiency of CO2 utilization at an I of 1200 than of 500 mu mol m(-2) s(-1). A decrease in I from 1200 to 500 mu mol m(-2) s(-1)| however| did not prevent a curvilinear increase in P-N at increased CO2 concentrations. In contrast| F. crenata seedlings showed less difference in PN between low-I and high-I environments. Nonetheless| F. crenata showed a greater CO2 response| with alpha increased by 25 % from 350 to 700 mu mol(CO2) mol(-1). alpha of Q. crispula| however| increased by less than 20 % as CO2 concentration increased from 350 to 700 mu mol mol(-1). The higher P-N at high CO2 concentration under low I was attributed to the CO2 concentration accompanied by a significant decrease in compensation irradiance. These results suggest that the continuous increase in global CO2 concentrations will directly result in an increase in photosynthetic efficiencies of both F. crenata and Q. crispula. The competitive relationship between the two species will change if a doubling of atmospheric CO2 concentration occurs;by the mid of the 21(st) century| with F. crenata benefiting more from CO2 fertilization than Q. crispula. 4162,1996,2,4,Effects of elevated CO2 concentration and climate-warming on photosynthesis during winter in Lolium perenne,Long-term effects of atmospheric carbon dioxide concentration (ambient or 700 mu mol mol(-1)) and air temperature (simulation of field conditions or +4 degrees C) on leaf photosynthetic rate were examined in Lolium perenne L. cv. Vigor| exposed to natural illumination during winter. Photosynthetic capacity was compared over a range of air temperatures and photon flux densities of photosynthetically active radiation which were representative of winter climate (5-15 degrees C and 0-500 mu mol m(-2) s(-1))| with CO2 level during measurement similar to that during the experimental period| Long-term exposure to increased air temperature reduced leaf CO2 fixation capacity by 23% (averaged over all measurement conditions)| resulting from a decline in light-saturated uptake rate| but not in incident-light quantum efficiency| CO2-stimulation was largely absent in plants grown in ambient temperature| but pronounced in plants grown under +4 degrees C| where it compensated for two-thirds of the 23% drop. This enhancing effect of elevated CO2 level on leaf CO2 uptake rate observed in the warmer treatment| was strongly dependent on measurement temperature| increasing from 5% at 5 degrees C| to up to 32% at 15 degrees C. Measurements of chlorophyll fluorescence and dry matter corresponded with the observed changes in assimilation capacity| which could not be attributed to a deteriorated nitrogen status of the leaves as there was a similar N content on an area basis. Several hypotheses are considered to explain the observed CO2-temperature interactions. 2469,1996,2,4,Effects of elevated CO2 concentration and high temperature on growth and yield of rice,Phenological development| biomass production and the related growth characteristics of rice (cv Akihikari) in canopy were measured over the entire growth period under different CO2 concentrations and air temperature regimes in temperature gradient chambers (TGCs)| in order to clarify the effects of anticipated global climate change on rice production. The TGC is a plastic tunnel with the dimensions of 26m in length| 2. 05m in width and 1.7m in height in which air was ventilated at varying rates to created a 4 degrees C temperature gradient along its longitudinal axis. Two TGCs were used for this experiment;one was kept at ambient CO2 (congruent to 350 mu LL(-1)) concentration and the other at 690 mu LL(-1) throughout the entire growth period. CO2 x temperature treatmets were applied to potted rice plants displaced in TGC at the density of 20 hills m(-2) in 1991| and on transplanted plants on soil bed in TGC at 25 hills m(-2) in 1992. In both years| a sufficient amount of nutrition was applied in split. The nearly doubled CO2 concentration (690 mu LL(-1)) accelerated phenological development of rice toward heading with more pronounced effects at higher temperatures. The number of days to heading of elevated CO2 plants at 30 degrees C was 11% less than that of ambient CO2 plants. The elevated CO2 concentration remarkably promoted both total and productive tiller numbers| whereas it gave a negligibly small effect on plant height. Also| the elevated CO2 concentration gave minor effects on leaf area index except at the initial growth stage| coinciding with the previous workers' results. The elevated CO2 concentration markedly promoted crop dry matter production| on which temperature appeared to give negligibly small effects. The relative enhancement rate by the doubled CO2 on crop dry weight at maturity was estimated to be 24% as average over the entire temperature range (26 similar to 30 degrees C) in both years. The insensitive temperature response in the enhancement rate was contrary to previous workers' results. This is considered to be due to previous workers' results being based on largely isolated plants where radiation might less limit the growth than in the present experiment in the canopy condition. 4098,1996,2,4,Effects of elevated summer temperatures and reduced pH on metabolism and growth of juvenile rainbow trout (Oncorhynchus mykiss) on unlimited ration,Juvenile trout (Oncorhynchus mykiss) were exposed to a simulated global warming - acidic water scenario over a 90-day summer period (control temperature range 13-24 degrees C). The addition of 2 degrees C to the fluctuating summer cycle of inshore Lake Ontario and H2SO4 to synthetic soft water resulted in four treatments: control| acidification of control| simulated global warming alone| and global warming plus acidification. The twice-daily feeding regime raised metabolic rates to similar to 75% of Mo-2(max). Large increases (from 4.5 to 11.5%) in whole-body lipid| smaller increases (from 12.0 to 15.5%) in protein| and compensating decreases in water content (from 77 to 71%) occurred in all treatments over time. The addition of 2 degrees C resulted in depressed appetites and growth| particularly after the period of peak temperature (days 60-90; 26 degrees C). Metabolic rate and nitrogenous waste excretion were also depressed. Overall| exposure to low pH resulted in increased appetites and growth| the increase of 2 degrees C reduced gross energy intake and increased fecal energy losses| and exposure to low pH resulted in increased energy intake and gain and better conversion efficiency. The lack of ionoregulatory disturbance in trout chronically exposed to pH 5.2 suggested that dietary NaCl may have compensated for branchial ion losses. 2510,1996,2,3,Effects of enhanced solar UV-B radiation on phytoplankton,Phytoplankton is the basis of the extended aquatic food webs and any reduction in biomass productivity due to increased levels of solar UV-B radiation (280-315 nm) is bound to have detrimental effects. In addition| the oceans play a key role with respect to global warming as marine phytoplankton are a major sink for atmospheric carbon dioxide. Phytoplankton are not uniformly distributed throughout the oceans of the world. The highest concentrations are found at high latitudes while| with the exception of upwelling areas on the continental shelves| the tropics and subtropics have 10 to 100 times lower concentrations. In addition to other factors solar UV-B radiation may play a role in phytoplankton distributions. Phytoplankton productivity is limited to the euphotic zone| the upper layer of the water column in which there is sufficient sunlight to support net productivity. Here they are exposed to solar UV-B radiation which affects orientation and motility as well as photosynthesis| nitrogen uptake and other key physiological processes. Work in the Antarctic has shown a direct reduction in phytoplankton production due to ozone-related increases in UV-B. 4253,1996,3,3,Effects of N management on N2O and CH4 fluxes and N-15 - Recovery in an irrigated mountain meadow,Forage production in irrigated mountain meadows plays a vital role in the livestock industry in Colorado and Wyoming. Mountain meadows are areas of intensive fertilization and irrigation which may impact regional CH4 and N2O fluxes. Nitrogen fertilization typically increases yields| but N-use efficiency is generally low. Neither the amount of fertilizer-N recovered by the forage nor the effect on N2O and CH4 emissions were known. These trace gases are long-lived in the atmosphere and contribute to global warming potential and stratospheric ozone depletion. From 1991 through 1993 studies were conducted to determine the effect of N source| and timing of N-fertilization on forage yield| N-uptake| and trace gas fluxes at the CSU Beef Improvement Center near Saratoga| Wyoming. Plots were fertilized with 168 kg N ha(-1). Microplots labeled with N-15-fertilizer were established to trace the fate of the added N. Weekly fluxes of N2O and CH4 were measured during the snow-free periods of the year. Although CH4 was consumed when soils were drying| flood irrigation converted the meadow into a net source of CH4. Nitrogen fertilization did not affect CH4 flux but increased N2O emissions. About 5% of the applied N was lost as N2O from spring applied NH4NO3| far greater than the amount lost as N2O from urea or fall applied NH4NO3. Fertilizer N additions increased forage biomass to a maximum of 14.6 Mg ha(-1) with spring applied NH4NO3. Plant uptake of N-fertilizer was greater with spring applications (42%)| than with fall applications (22%). 4188,1996,3,3,Efficient electrical end-use technologies for mitigating greenhouse gas emissions in Africa,International concern about the impacts of global warming has resulted in cooperative activity among developed and developing nations to address the issue. Already| developed countries have agreed to reduce carbon dioxide emissions to 1990 levels by the year 2000. At the United Nations Framework Convention on Climate Change (FCCC)| developed countries agreed to meet the incremental costs of reducing the emissions of greenhouse gases. One possible avenue for effecting the provisions of the FCCC is joint implementation (JI) projects involving developed and developing countries. This article looks at a sample of African countries that are at different levels of development. It identifies resource options that| when used in an integrated resource planning contact| prove to be cost effective as well as environmentally benign. II investigates these options| particularly energy efficient appliances and compact fluorescent lamps (CFLs) in terms of their effects on the planning and operations of electric utilities and on their emission of global warming gases. The authors hope that the article will be helpful in developing criteria for selecting and prioritizing JI projects. It focuses on Africa because it appears that| unlike Asia and Latin America| the least amount of information has been published for this continent in general. 4160,1996,2,3,El Nino-like climate change in a model with increased atmospheric CO2 concentrations,SEA surface temperatures in the tropical Pacific Ocean increased on average by several tenths of a degree during the 1980s and early 1990s(1-4)| contributing to the observed global warming during this period(5). Here we investigate the possible causes of this Pacific warming| using a global coupled ocean-atmosphere general circulation model incorporating increasing concentrations of atmospheric carbon dioxide| In the model| cloud cover and cloud albedo feedbacks contribute to tropical Pacific sea surface temperature increases that are greater east of 180 degrees longitude| with attendant shifts in large-scale precipitation patterns and mid-latitude circulation anomalies in the north Pacific. These anomalies resemble some aspects of El Nino events| as well as features associated with recent observed Pacific-region climate anomalies. The resemblance to El Nino complicates the problem of detection and attribution of climate change| and suggests that depletion of freshwater resources(6) may be an additional hazard of greenhouse warming for populations in the western Pacific region.
2532,1996,4,4,Energy demand and supply in metropolitan New York with global climate change,The purpose of this paper is to provide background information for a scenario planning exercise. It draws on several different sources| but the primary ones are an evaluation of carbon dioxide emission control strategies using the energy and environmental systems model| MARKAL| and the New York State Energy Plan| its technical appendices and other reports from the State Energy Office. The former applied computer modelling that is sensitive to cost assumptions. The modelling period extended to 2028. The analysis was intended to explore the range of possibilities rather than to assess policies that were actually under consideration by the State. The State Energy Plan draws on a wider range of information and analysis techniques. It provides projections to 2012| but often focuses on current action and proposals. The two are not in conflict; they serve complementary purposes.
2527,1996,2,4,Environmental and endocrine control of reproduction in two species of polychaete: Potential bio-indicators for global climate exchange,An in vitro bioassay has been developed which shows that oogenesis in Harmothoe imbricata is controlled by a gonadotrophic hormone which promotes egg protein synthesis in developing oocytes. A similar endocrine control mechanism is found in Eulalia viridis and analysis of in vivo assays indicate that the hormone acts as a transducer between the environment and the gamete. The timing of gametogenesis is controlled by environmental cues in both species and may be affected by predicted global climate change. With the development of these sensitive hormone assays it is possible to test the impact of climate change on both species| providing a possible early warning system for global warming and potential bio-indicators of climate change. Harmothoe imbricata is likely to be the more sensitive indicator species. 4100,1996,3,4,Environmental and health benefits of district cooling using utility-based cogeneration in Ontario| Canada,Environmental and health benefits are shown to be possible in the province of Ontario by using heat cogenerated from the facilities of the main provincial electrical utility| Ontario Hydro| to drive absorption chillers which supply the cooling needs of district-cooling networks in the province. Two district-cooling scenarios are assessed. The first assumes implementation of utility-based cogeneration/absorption chilling to satisfy a minor portion of the cooling demands of the residential-commercial-institutional sector. The other scenario is similar| but assumes a larger portion of the sector cooling demands are satisfied using utility-based cogeneration/absorption chilling. Presented in the assessments are (i) data on fuel-cycle emissions| environmental and health effects| and associated economic costs of the existing Ontario Hydro energy system and (ii) the reductions in emissions| effects and environmental and health costs predicted for each scenario. Effects considered include mortality| morbidity| lost work days| lost crop yield| lost fish yield| building damage| global warming and aquatic thermal effects. Copyright (C) 1996 Elsevier Science Ltd. 4133,1996,3,4,Environmental impact of biomethanogenesis,The environmental impact of biomethanogenesis is related to its ecological role| accumulation and effect as a greenhouse gas| and application in anaerobic digestion for conversion of biomass and wastes to methane and compost. Biological formation of methane is the process by which bacteria decompose organic matter using carbon dioxide as an electron acceptor in the absence of dioxygen or other electron accepters. This microbial activity is responsible for carbon recycling in anaerobic environments| including wetlands| rice fields| intestines of animals sediments| and manures. The mixed consortium of microorganisms involved includes a unique group of bacteria| the methanogens| which may be considered to be in a separate kingdom based on genetic and phylogenetic variance from all other life forms. Because methane is a significant and increasing greenhouse gas| its source fluxes and their potential reduction are of concern. Biomethanogenesis may be harnessed for reduction of wastes and conversion of renewable resources to significant quantities of substitute natural gas which could mitigate carbon dioxide and other pollutants related to use of fossil fuels. 4205,1996,3,4,Environmental integrity| racism and health,Environmental degradation seriously affects human health. Thus| a close relationship exists between the protection of ecosystem integrity and wilderness on one hand| and human health on the other. However| there is an overarching| holistic perspective in laws and regulations - as well as morality - to maintain a healthy relationship between the two. Problem areas focused on in this paper are: (a) climate change and global warming; (b) food production; and (c) global equity. This paper argues for the principle of integrity| which provides an holistic perspective| suggested as a better approach than that of current regulations to mitigate against associated threats to human health. 4271,1996,3,4,Environmental life cycle analyses of transport systems,The importance of fuel cells for future low emission transportation systems is well known| but in order to obtain a complete picture of the benefits there is a need to consider the environmental impact of such systems over their lifetime from manufacture to disposal. This paper presents the preliminary results of environmental life cycle analyses of fuel cell vehicle drives and other low pollution options| thus enabling a comparative assessment to be made. 4203,1996,3,3,Environmental protection in the electronic and electrical industries,Global environment conservation in the electronic and electrical industries is discussed in this paper from three stand-points: the prevention of pollution and contamination| global environmental problems and the development of products contributing to environmental protection in the society. These can be summarized as follows: (i) to prevent pollution and contamination in manufacturing activities by way of environmental management and investment for improvements Hitachi has invested for the last twenty years; (ii) to establish an action program for environmental issues such as ozone-layer protection| global-warming prevention| industrial-waste reduction and products recycling; and (iii) to innovate and develop product technologies for the improvement of energy efficiency| contributing to the prevention of global warming. 4150,1996,2,4,Equilibrium and transient global| warming scenario implications for water resources in Wales,A methodology has been developed to predict the responses of a range of water supply sources in Wales to global warming scenarios. Hydrologically effective rainfall is predicted from temperature and precipitation for each season based on site specific formulae developed using the Meteorological Office Rainfall and Evaporation Calculation System (MORECS) and UK Surface Water Archive databases. Comparisons are then made between the effects predicted for the scenarios established from equilibrium simulations and the new Hadley Centre High Resolution Model (UKHI) transient mode results. Though very different| both suggest increased stress on water resources late in the hydrological year. 4109,1996,2,3,Estimates of indirect global warming potentials for CH4| CO AND NOX,Emissions may affect climate indirectly through chemical interactions in the atmosphere| but quantifications of such effects are difficult and uncertain due to incomplete knowledge and inadequate methods. A preliminary assessment of the climatic impact of changes in tropospheric O-3 and CH4 in response to various emissions is given. For a 10% increase in the CH4 emissions the relative increase in concentration has been estimated to be 37% larger. The radiative forcing from enhanced levels of tropospheric O-3 is estimated to 37% of the forcing from changes in CH4. Inclusion of indirect effects approximately doubles the climatic impact of CH4 emissions. Emissions of NOx increase tropospheric O-3| while the levels of CH4 are reduced. For emissions of NOx from aircraft| the positive effects via O-3 changes are significantly larger than the negative through changes in CH4. For NOx emitted from surface sources| the effects through changes in O-3 and CH4 are estimated to be of similar magnitude and large uncertainty is connected to the sign of the net effect. Emissions of CO have positive indirect effects on climate through enhanced levels of tropospheric O-3 and increased lifetime of CH4. These results form the basis for estimates of global warming potentials for sustained step increases in emissions. 2489,1996,2,4,Estimating daily wind speed under climate change,A semi-empirical downscaling approach is presented to estimate spatial and temporal statistical properties of local daily mean wind speed under global climate change. The present semi-empirical downscaling method consists of two elements. Since general circulation models (GCMs) are able to reproduce the features of the present atmospheric general circulation quite correctly| the first element represents the large-scale circulation of the atmosphere. The second element is a link between local wind speed and large-scale circulation pattern (CP). The linkage is expressed by a stochastic model conditioned on CP types. Parameters of the linkage model are estimated using observed data series; then this model is utilized with GCM-generated CP type data corresponding to a 2 x CO2 scenario. Under the climate of Nebraska the lognormal distribution is the best two-parameter distribution to describe daily mean wind speed. The space-time variability of wind speed is described by a transformed multivariate autoregressive (AR) process| and the linkage between local wind and large-scale circulation is expressed as a conditional AR process| i.e. the autoregressive parameters depend on the actual daily CP type. The basic tendency of change under 2 x CO2 climate is a considerable increase of wind speed from the beginning of summer to the end of winter and a somewhat smaller wind decrease in spring. Copyright (C) 1996 Elsevier Science Ltd. 4210,1996,4,4,Estimation of areal flux of atmospheric methane in an urban area of Nagoya| Japan| inferred from atmospheric radon-222 data,To clarify the emission of methane (CH4) from area sources| we have adopted atmospheric radon-222 (Rn-222) as a natural tracer. The diurnal variation in CH4 concentration is predominantly affected by local meteorological conditions as is the case of Rn-222. Positive correlations are recognized between atmospheric CH4 and Rn-222 concentrations. From these correlations| the CH4 flux from urban area in Nagoya| Japan| was estimated to be almost constant at 0.02 gCH(4) m(-2) d(-1) over a year. 4139,1996,2,4,Evaluating eolian-climatic interactions using a regional climate model from Hanford| Washington (USA),A regional climate model (RCM) developed for the Hanford Site| Washington illustrates a potentially useful method for assessing eolian responses to regional climate change. The RCM is based on long-term relations between fundamental climatic variables of precipitation| temperature| and wind speed. Modelled data are integrated into eolian-climatic scenarios through maps of eolian susceptibility| plots of sand dune mobility| and calculated trends of unvegetated dune sand volumes. Results demonstrate the sensitivity of eolian-climatic interactions to small changes in precipitation. Analyses suggest that continuation of the 1977-1987 trend toward a cooler (-0.16 degrees C) and wetter (+1.8 cm yr(-1)) climate over the next 10-15 years will result in a decrease of similar to 18% in the volume of unvegetated dune sand. Further temperature reductions totaling 0.7 degrees C would promote precipitation increases of 30% leading to an additional reduction of 98% in the volume of unvegetated dune sand. Modelling scenarios for a possible global warming of +4 degrees C indicate that annual precipitation at Hanford would be negligible and vegetation would be eliminated from dune surfaces. Sand dune mobility would increase by over 400%. 4176,1996,2,4,Extinctions of montane mammals reconsidered: Putting a global-warming scenario on ice,McDonald and Brown developed a model based on island biogeographic principles to predict the magnitude and composition of small mammal extinctions from isolated boreal habitats atop mountains of the Great Basin following global warming. The model predicts that three of 14 boreal mammals will go extinct regionally and that four of 19 mountain ranges will lose upwards of 50% of their present faunas. Here| we re-examine the model on the basis of its underlying assumptions| on the statistical and biogeographic protocols used| and on its predictive power. A key assumption| that populations of these small mammals are isolated by absolute barriers to dispersal| is challenged by published field observations and by extensive trapping records. Statistical procedures used to construct the model are questionable and the model itself yields imprecise estimates. The biogeographic principle used to identify extinction-prone species| nested subsets of species| makes predictions that are at odds with available autecological information. The demonstration of a nested pattern of species occurrences does not provide definitive evidence in resolving SLOSS - or whether a single large island or several small islands of equivalent total area will contain more species. We conclude that the model is not a reliable method for forecasting species extinctions following global warming. The final resolution of the biogeography of montane mammals (and predictive models of extinction) in the Great Basin must await a full and accurate accounting of past and present species distributions. 4097,1996,4,4,Extrapolation problems in modeling fire effects at large spatial scales: A review,Models of vegetation change in response to global warming need to incorporate the effects of disturbance at broad spatial scales. Process-based predictive models| whether for fire behavior or fire effects on vegetation| assume homogeneity of crucial inputs over the spatial scale to which they are applied. Landscape disturbance models predict final burning patterns| but either do not model mechanistic behavior and explicit spread rates| or require large amounts of data to initialize simulations and predict ecological effects. Empirical data on the ecological effects of fire are not generally available at these scales| and conclusions are often extrapolated upward from stand-level data. Three methods for extrapolating ecological effects of fire across spatial scales and the sources of error associated with each were identified: (1) extrapolating fire behavior models directly to larger spatial scales; (2) integrating fire behavior and fire effects models with successional models at the stand level| then extrapolating upward; and (3) aggregating model inputs to the scale of interest. Extreme fire events present a challenging problem for modelers| regardless of which extrapolation method is employed. No single approach to modeling fire effects is inherently superior; modeling objectives and the characteristics of specific systems will determine the best strategy for each situation. 2493,1996,2,4,Forest floor carbon pools and fluxes along a regional climate gradient in Maine| USA,Global carbon (C) reserves in soil are large compared with atmospheric stocks (in the form of CO2 and methane)| so small changes in soil C storage will have a significant effect on atmospheric CO2 concentrations. In order to better understand the consequences of global climate change| it is essential that we define how soil C storage is influenced by changes in temperature and moisture that are expected as a result of global climate change| Forest floor carbon pools and fluxes were evaluated at 16 northern hardwood sites located within four distinct climate regions (Northern| Central| Southern and Coastal) in Maine. Mean annual air temperature at the sites ranged from 2.0 degrees C in the Northern region to 6.2 degrees C in the Coastal region and average annual precipitation ranged from 90 cm in the Northern region to 140 cm in the Coastal region. Leaf litter mass and leaf litter C flux were not correlated with temperature indices and did not vary among regions| However| they were positively correlated with annual precipitation| suggesting that litter production was controlled| in part at least| by precipitation but not by temperature. Northern sites stored more C in the forest floor than Coastal sites| and they experienced slower decomposition rates. Because soil and vegetation characteristics of these sites were similar| we attribute these trends to differences in climate| Indeed| C turnover time was correlated with latitude and temperature indices| Slower decomposition in the Northern region was attributed to a combination of lower specific activity at temperatures below 13 degrees C| cooler average temperatures and a shorter frost-free season. Soil respiration at each site was positively correlated with temperature and the slope of the relationship increased with latitude| indicating that the ability of the soil biota to respire C varied with climate| A predictive equation is presented that accounts for the change in slope with latitude. Because C loss through soil respiration was more sensitive to temperature than C inputs from litter| any regional warming in the next century may lead to a decrease in forest floor carbon storage| However| if precipitation increases with temperature| then litter C flux may increase and offset the increase in soil respiration. 4219,1996,2,4,Free air temperature increase (FATI): A new tool to study global warming effects on plants in the field,A new technique| called Free Air Temperature Increase (FATI)| was developed to artificially induce increased canopy temperature in field conditions without the use of enclosures. This acronym was chosen in analogy with FACE (Free Air CO2 Enrichment)| a technique which produces elevated CO2 concentrations [CO2] in open field conditions. The FATI system simulates global warming in small ecosystems of limited height| using infrared heaters from which all radiation below 800 nm is removed by selective cut-off filters to avoid undesirable photomorphogenetic effects. An electronic control circuit tracks the ambient canopy temperature in an unheated reference plot with thermocouples| and modulates the radiant energy from the lamps to produce a 2 5 degrees C increment in the canopy temperature of an associated heated plot (continuously day and night). This pre-set target differential is relatively constant over time due to the fast response of the lamps and the use of a proportional action controller (the standard deviation of this increment was <1 degrees C in a 3 week field study with 1007 measurements). Furthermore| the increase in leaf temperature does not depend on the vertical position within the canopy or on the height of the stand. Possible applications and alternative designs are discussed. 4195,1996,3,3,From joint implementation to a system of tradeable CO2 emission entitlements,A system of tradeable CO2 emission entitlements is an appealing approach to combat global warming at least from the theoretical point of view. But| when examining in more detail the possible criteria for distributions of CO2 entitlements-such as grandfathering or distribution per capita-it appears that an international agreement on the implementation of the entitlement system without introductory measures is quite improbable. The most important criterion that will determine whether such a distribution hey mill indeed be accepted is neglected| that is| the willingness to pay. Much has been written about the structures and theoretical advantages of joint implementation and tradeable permits But greenhouse gas emission reductions achievable with joint implementation as a single instrument will not be sufficient to protect the earth's atmosphere. At the same time| a system of tradeable emission Entitlements is unlikely to be established. This article suggests introducing the system of tradeable CO2 emission entitlements gradually| using stages of joint implementation in a stepwise manner. Using joint implementation to enter an entitlement system allows industrialized countries to adapt their self-defined emission quotas to their willingness to pay. The narrower the target| the higher the costs will be to avoid emissions in one's own country or elsewhere. The net-payers establish the level to which their emissions may rise without interferences| and the net-recipients distribute the available emission rights among themselves according to other criteria. Such ct differentiation of target definitions may not completely eliminate the difficulties of finding a consensus| but at least may reduce them. 2495,1996,2,4,Future availability of water in Egypt: The interaction of global| regional| and basin scale driving forces in the Nile Basin,This paper describes the impacts on the future availability of water in Egypt of driving forces operating at three different scales in the Nile Basin: global (climate change)| regional (land-use change) and river basin (water-resources management). Global and regional driving forces are taken from an integrated model for the assessment of climate change (IMAGE 2.0) and from the results of Global Climate Model experiments. Regional hydrologic models of the largest Nile tributaries are used to calculate the impacts on Main Nile discharge. River-basin driving forces are considered through a set of future water-resource management strategies in Egypt. The combined effects of all three driving forces on future water availability in Egypt range from a large water surplus to a large water deficit by the year 2050. This range of results arises from uncertainties in the integrated modelling approach used and from the different ways Egypt may approach population growth| agricultural policy and human aspirations for greater water use in the future. 4140,1996,4,3,Future ocean uptake of CO2: Interaction between ocean circulation and biology,We discuss the potential variations of the biological pump that can be expected from a change in the oceanic circulation in the ongoing global warming. The biogeochemical model is based on the assumption of a perfect stoichiometric composition (Redfield ratios) of organic material. Upwelling nutrients are transformed into organic particles that sink to the deep ocean according to observed profiles. The physical circulation model is driven by the warming pattern as derived from scenario computations of a fully coupled ocean-atmosphere model. The amplitude of the warming is determined from the varying concentration of atmospheric CO2. The model predicts a pronounced weakening of the thermohaline overturning. This is connected with a reduction of the transient uptake capacity of the ocean. It yields also a more effective removal of organic material from the surface which partly compensates the physical effects of solubility. Both effects are rather marginal for the evolution of atmospheric pCO(2). Running climate models and carbon cycle models separately seems to be justified. 4168,1996,3,4,Generation of methane from paddy fields and cattle in India| and its reduction at source,Methane (CH4) is a saturated organic gas. About 500 Tg yr(-1) methane is generated globally. It is evident that 70% of the total emission have anthropogenic sources. The paddy fields contribute a significant portion of the total methane generated. About 20% of the total methane is generated from the paddy fields. In India| methane efflux rate is negative to 49 mg m(-2) hr(-1). The mean CH4 flux from Indian paddy fields is calculated to be 4.0 Tg yr(-1). Livestock| and in particular ruminants are one of the important sources of methane emission on a global scale. There are two sources of methane emission from live stock: (1) from digestive process of ruminants. (2) from animal wastes. The estimated value of methane emission from digestive process of ruminants in India accounts for 6.47 Tg yr(-1)| and animal wastes accounts for 1.60 Tg yr(-1). Total generation of methane from animals in India is about 1.0 Tg yr(-1). In paddy fields the key of controlling methane emission lies in the control of irrigation water. The methane emission can be decreased drastically if the field is under dry conditions for a few days at the end of tillering. In the case of livestock| reduction of methane emission can be done by (1) increasing the intake of the animal (2) modifying the composition of the diet| (3) eliminating protozoa in rumen| (4) improving fibre digestion efficiency and (5) inhibiting activity of methanogenic bacteria. Copyright (C) 1996 Elsevier Science Ltd. 4166,1996,3,3,Geoengineering: Could or should we do it?,Schemes to modify large-scale environment systems or to control climate have been seriously proposed for over 50 years| some to (1) increase temperatures in high latitudes| (2) increase precipitation| (3) decrease sea ice| (4) create irrigation opportunities or to offset potential global warming by spreading dust in the stratosphere to reflect away an equivalent amount of solar energy. These and other proposed geoengineering schemes are briefly reviewed from a historical perspective. More recently| many such schemes to advertently modify climate have been proposed as cheaper methods to counteract inadvertent climatic modifications than conventional mitigation techniques such as carbon taxes or pollutant emissions regulations. Whereas proponents argue cost effectiveness| critics of geoengineering argue that there is too much uncertainty to either (1) be confident that any geoengineering scheme would work as planned| or (2) that the many decades of international political stability and cooperation needed for the continuous maintenance of such schemes to offset century long inadvertent efforts is problematic. Moreover| there is potential for transboundary conflicts should negative climatic events occur during geoengineering activities since| given all the large uncertainties| it could not be assured to victims of such events that the schemes were entirely unrelated to their damages. Nevertheless| although I believe it would be irresponsible to implement any large-scale geoengineering scheme until scientific| legal and management uncertainties are substantially narrowed| I do agree that| given the potential for large inadvertent climatic changes now being built into the earth system| more systematic study of the potential for geoengineering is probably needed. 4137,1996,2,3,Geomorphological 'hotspots' and global warming,If global warming takes place over coming decades as a consequence of 'the greenhouse effect' there are some environments which will be particularly sensitive. In this review| those geomorphological situations where change may be especially rapid in onset and marked in degree are examined. 4242,1996,4,4,Glacial isostatic adjustment and the anomalous tide gauge record of eastern North America,SEA-LEVEL variations| as recorded by the global network of tide gauges| represent a rich data set for studying a nide range of natural and anthropogenic phenomena| such as the sea-level rise induced by possible global warming| For this purpose| long-term sea-level trends must be corrected for the 'contaminating' effects of continuing glacial isostatic adjustment(1-5) (GIA). The numerical correction procedure has| for sites on the east coast of North America| yielded a set of highly anomalous sea-level rates characterized by systematic geographical trends(2|4|5). We demonstrate that these trends are a consequence of inadequacies in the previous 'standard' numerical prediction for GIA| In particular| we find that the well-known trends in the GIA-corrected tide gauge rates are eliminated if the lower-mantle viscosity of the Earth model used in the GIA prediction is increased. This result obviates the need to explain the anomalous trend as a manifestation of Gulf Stream ocean circulation(4) or neotectonic processes(2). 4104,1996,2,4,Glacier monitoring for climate change detection in Nunavut,Nunavut contains approximately 75% of Canada's total glacierized area. The high arctic ice caps have received the most consistent monitoring| whereas glaciers on Baffin Island have been monitored for shorter intervals since the 1960s. Although mass balance data for selected Baffin glaciers show no clear trend over the monitoring period| there appears to be reasonable agreement between summer temperature and annual mass balance. In contrast to global warming trends| the Baffin region has experienced a general cooling over the last 30 years| particularly in winter. The cause of this cooling is not fully understood and its impact on the local ice cover is uncertain. In order to address these issues| mass balance observations should be resumed on a suitable glacier as part of an integrated environmental monitoring program in the region. 2473,1996,2,2,Global change and coral reefs: Impacts on reefs| economies and human cultures,Coral reefs have reconstituted themselves after previous large sea-level variations| and climate changes. For the past 6000 years of unusually stable sea-level| reefs have grown without serious interruptions. During recent decades| however| new stresses threaten localized devastation of many reefs. A new period of global climate change is occurring| stimulated by anthropogenic increases in greenhouse gases. Coral reefs will cope well with predicted sea-level rises of 4.5 cm per decade| but reef islands will not. Higher sea levels will provide corals with greater room for growth across reef flats| but there are no foreseeable mechanisms for reef island growth to keep pace with sea-level rise| therefore many low islands may ultimately become uninhabitable. Climate change will introduce localized variations in weather patterns| but changes to individual reefs cannot be predicted. Reefs on average should cope well with regional climate change| as they have coped with similar previous fluctuations. Air temperature increases of 0.2-0.3 degrees C/decade will induce slower increases in sea-surface temperatures| which may cause localized| or regional increases in coral bleaching. Changes in rainfall will impact on reefs near land masses. Likewise| increased storms and variations in El Nino Southern Oscillation (ENSO) may stress some reefs| but not others. The greatest impact of climate change will be a synergistic enhancement of direct anthropogenic stresses (excessive sediment and pollution from the land; over-fishing| especially via destructive methods; mining of coral rock and sand; and engineering modifications)| which currently cause most damage to coral reefs. Many of the world's reefs have been degraded and more will be damaged as anthropogenic impacts increase under the 'demophoric' increases in population (demos) and economic (phoric) activity. This biotic and habitat loss will result in severe economic and social losses. Reefs| however| have considerable recovery powers and losses can be minimized by effective management of direct human impacts and reducing indirect threats of global climate change. 4174,1996,4,4,Global surface air temperature in 1995: Return to pre-Pinatubo level,Global surface air temperature has increased about 0.5 degrees C from the minimum of mid-1992| a year after the Mt. Pinatubo eruption. Both a land-based surface air temperature record and a land-marine temperature index place the meteorological year 1995 at approximately the same level as 1990| previously the warmest year in the period of instrumental data. As El Nino warming was small in 1995| the solar cycle near a minimum| and ozone depletion near record levels| the observed high temperature supports the contention of an underlying global warming trend. The pattern of Northern Hemisphere temperature change in recent decades appears to reflect a change of atmospheric dynamics. 4099,1996,3,4,Global warming and developing countries - The possibility of a solution by accelerating development,There are concerns that the rapid development of the developing countries will hasten global warming and exacerbate resource problems. That is to say| it is quite possible that we cannot solve the North-South problem while at the same time containing global warming and conserving fossil fuels. But this paper attempts to show that| on the contrary| the fast development of these countries might very well bring about a long-term solution of the global warming problem. A model incorporating development stage theory is built and used to calculate by region the world's economic growth| population growth| energy supply and demand| CO2 emissions and other items up to the end of the 21st century. Results indicated that if in 2100 world population is about 10 billion (it was 5.1 billion in 1990)| world GDP is US$200 trillion (1987 prices; it was US$20 trillion in 1990) and CO2 emissions are 10 billion tonnes (carbon equivalent; they were 5.8 billion tonnes in 1990)| there will be fairly good prospects for solving the North-South| fossil fuel exhaustion and global warming problems. Making this scenario happen will require accelerating development of the developing countries so they quickly join the ranks of the developed countries| expediting the shift to renewable energy in the developed countries by imposing carbon taxes| transferring energy saving technologies from the developed to the developing countries| and other efforts. Copyright (C) 1996 Elsevier Science Ltd. 4215,1996,4,2,Global warming and global dioxide emission: An empirical study,In this paper| the dynamic relationship between global surface temperature (global warming) and global carbon dioxide emission (CO2) is modelled and analyzed by causality and spectral analysis in the time domain and frequency domain| respectively. Historical data of global CO2 emission and global surface temperature anomalies over 129 years from 1860-1988 are used in this study. The causal relationship between the two phenomena is first examined using the Sim and Granger causality test in the time domain after the data series are filtered by ARIMA models. The Granger causal relationship is further scrutinized and confirmed by cross-spectral and multichannel spectral analysis in the frequency domain. The evidence found from both analyses proves that there is a positive causal relationship between the two variables. The time domain analysis suggests that Granger causality exists between global surface temperature and global CO2 emission. Further| CO2 emission causes the change in temperature. The conclusions are further confirmed by the frequency domain analysis| which indicates that the increase in CO2 emission causes climate warming because a high coherence exists between the two variables. Furthermore| it is proved that climate changes happen after an increase in CO2 emission| which confirms that the increase in CO2 emission does cause global warming. (C) 1996 Academic Press Limited 4146,1996,2,4,Global warming and health: A review,The paper looks at the phenomenon of global warming and its potential health effects and outlines a number of plausible response by the health sector in developing countries to its threat. It suggests that the health sector should facilitate an international effort at adressing this challenge| mainly through advocacy| epidemiological surveillance and awareness creation. 4269,1996,2,3,Global warming and the hydrologic cycle,Starting with a review of the basic processes that govern greenhouse warming| we have demonstrated that the hydrologic cycle plays a key role in the heat balance of the Earth's surface-atmosphere system. Through the water and other climatic feedbacks| the hydrologic cycle is shown to be a key factor in the climate's evolution as greenhouse gases continue to build up in the atmosphere. This paper examines the current predictive capability of general circulation models linked with macroscale and landscape-scale hydrologic models that simulate regional and local hydrologic regimes under global warming scenarios| Issues concerning hydrologic model calibration and validation in the context of climate change are addressed herein| It is shown that the natural uncertainty in hydrologic regimes in the present climate introduces a signal-to-noise interpretation problem for discerning greenhouse-induced variations in regional hydrologic regimes. Simulations of river basins by means of macroscale hydrologic models nested within general circulation models have been implemented in a few selected cases. From the perspective of water resources management| such simulations| carried out in detail under greenhouse-warming scenarios in midlatitudinal basins of the United States| predict shorter winter seasons| larger winter floods| drier and more frequent summer weather| and overall enhanced and protracted hydrologic variability. All these predictions point to potentially worsening conditions for flood control| water storage| and water supply in areas of semiarid midlatitudinal climates currently dependent of spring snowmelt. Little information of this type is currently available for other areas of the world. Practice of sound water resources engineering principles ought to be adequate to cope with additional hydrologic uncertainty that might arise from global warming. 4171,1996,2,4,Global warming and the regional persistence of a temperate-zone insect (Tenodera sinensis),Models based on the paleoecological record predict that animals in temperate regions will respond to global warming by migrating poleward to remain within their temperature tolerance ranges. The effect of global warming on invertebrates is of great concern because of their critical role in ecosystem structure and function. Migration poses a problem for many species because of their limited dispersal abilities. The life cycle of a typical temperate zone univoltine insect| Tenodera sinensis (Mantodea: Mantidae) is constrained by degree-days per season: too few prevent maturation before the killing frost in the autumn; too many allow egg hatch before a killing frost. We used field and laboratory observations on the life history and ecology of this species to predict the effect of global warming on the regional distribution of this insect by the end of the next century. Based on the simplified| best-case| biological assumptions of our model| the geographical range of TT: sinensis in eastern North America would be compressed toward the northern part of its present contiguous regional distribution. This and other univoltine temperate species with long maturation periods and low vagility could face regional extinction if global warming predictions are accurate. 4222,1996,2,3,Global warming and the species richness of bats in Texas,General circulation models provide predictions for global climate under scenarios of increased atmospheric CO2. Climate change is expected to lead directly to changes in distributions of vegetation associations. Distribution of animals will also change to the extent that animals rely on vegetation for food or shelter. Bat species in Texas appear to be restricted| in part| by the availability of roosts. We used geographic information systems and the Holdridge vegetation-climate association scheme to model the effect of climate change on bat distributions and species richness in Texas. Habitat characteristics for each species were identified from the literature and included vegetation| topography| and availability of caves. We assumed caves and topography to be fixed relative to climate. Vegetation changes were predicted from the Holdridge vegetation-climate association scheme. The redistribution of bats following climate change was predicted based on the new locations of suitable habitat characteristics. Under conditions of global warming tropical forests were predicted to expand into Texas; tree-roosting bats were sensitive to this change in vegetation. Cavity-roosting bats were less affected by changes in vegetation| but| where response was predicted| ranges decline. 4163,1996,2,4,Global warming impacts on lake trout in arctic lakes,Arctic freshwater ecosystems may be sensitive indicators of climatic warming trends because they have relatively few species and simple food webs. Many of these systems are dominated by lake trout| which act as keystone predators. For arctic Alaska Toolik Lake| we have a 16-yr record of physical| chemical| and biological data. Our temperature data show a 3 degrees C increase in mean July epilimnetic temperatures. An individual-based bioenergetics model for young-of-year (YOY) lake trout in the lake was used to examine the effects of climate warming on growth of YOY lake trout. Our simulation models predicted that with a July temperature increase| YOY lake trout would need to consume >8-fold more food (>10-fold with seasonally increased temperatures) to achieve the same end-of-year size as historically surviving YOY lake trout. We have observed no increase in food availability in the lake| and recent analysis shows that primary productivity has actually decreased. If recent changes in the lake foreshadow a long-term trend| our model results suggest that YOY lake trout will not survive their first winter. Such changes| coupled with other current anthropogenic impacts in the arctic| may disrupt lake trout control of the trophic structure in arctic lakes.
4107,1996,4,4,Global warming in a coupled climate model including oceanic eddy-induced advection,The Gent and McWilliams (GM) parameterization for large-scale water transport caused by mesoscale oceanic eddies is introduced into the oceanic component of a global coupled ocean-atmosphere model. Parallel simulations with and without the GM scheme are performed to examine the effect of this parameterization on model behavior under constant atmospheric CO2 and on the model response to increasing CO2. The control (constant CO2) runs show substantial differences in the oceanic stratification and extent of convection| similar to differences found previously using uncoupled ocean models. The transient (increasing CO2) runs show moderate differences in the rate of oceanic heat sequestration (less in the GM case)| as expected based on passive tracer uptake studies. However| the surface warming is weaker in the GM case| especially over the Southern Ocean| which is contrary to some recent supposition. Reasons for the reduced warming in the GM case are discussed. 4198,1996,3,4,Global warming mitigation strategies,Mitigation strategies have been explored| and these topics will be discussed with emphasis on terrestrial ecosystem sequestration as an illustration of successful research. The use of halophyte horticulture for near-term solution to environmental problems and for food application has been demonstrated and is in commercial production in Mexico and Saudi Arabia. Halophyte horticulture fixes carbon from the atmosphere using desert land areas and features sea water for irrigation. 4279,1996,3,3,Global warming| infrastructure| and land use in the metropolitan New York area - Prevention and response,The metropolitan area of New York| New Jersey and Connecticut is surrounded by an extensive shoreline| portions of which have the highest population density in the country. The shoreline at the same time affords amenities and vulnerabilities to natural and man-made disasters| such as the potential perils of global warming. Predicted changes in sea level attributable to global warming may claim much of the waterfront areas that have been redeveloped for public use over many decades. Changes in shoreline populations and economic activity induced by global warming necessarily affect the entire metropolitan area. Infrastructure plays a critical role both in protecting existing human settlements and in changing settlement patterns to reduce their contribution to global warming in the future. This paper addresses the vulnerability of infrastructure to the projected or estimated conditions (primarily sea level change) associated with global warming and the extent to which infrastructure can be modified to reduce its vulnerability and consequently| that of the land uses it serves (see Miller'). Two approaches or scenarios are addressed. I) In the short term| measures can be taken that are more responsive and reactive. That is| given that global warming will occur| those measures would reduce the likelihood that the immediate consequences of global warming would be felt by the area's population and economic activity. 2) Over a longer time period| the key issue is whether infrastructure changes such as relocation| redesign| retrofit| or renovation can be accomplished in a way that reduces the contribution of infrastructure and land use activities to global warming. Examples of such reduction strategies are energy conservation and/or emission reduction. In addressing these two perspectives| the focus will be upon infrastructure and its relationship to land use. Changes that might occur in the area's land uses directly in reaction to global warming (not associated with the services the area's infrastructure provides) or for other reasons| are not addressed here. These approaches or scenarios operate in the context of anticipated impacts or consequences of global warming. Therefore| before addressing the infrastructure and land use dimensions| the impacts of global warming (in terms of sea level rise) that are assumed will be briefly set forth.
4249,1996,4,3,Greenhouse gas emissions from the use of primary energy in forest operations and long-distance transportation of timber in Finland,In Finland in 1993 the greenhouse gas emissions caused by machinery used in silvicultural and forest improvement work| wood harvesting| and timber transportation were 424.2 Gg carbon dioxide (CO2) (Gg = gigagram = 10(9) g)| 10.6 Mg nitrous oxide (Mg = megagram = 10(6) g)| 3.5 Gg carbon monoxide| 31.5 Mg methane| 5.6 Gg nitrogen oxide| and 0.7 Gg non-methane volatile organic compounds. When emissions were converted into equal units as global warming potential in terms of CO2| the warming effects on a 20-year time frame equalled 1310 Gg as CO2 and on a 100-year time frame 669 Gg as CO2. The proportion of silvicultural and forest improvement work of the total emission was 8 per cent| cutting of timber 13 per cent| haulage 18 per cent| long-distance transportation 57 per cent| and transportation of machinery 4 per cent. The emissions caused by the use of primary energy in forestry seem to be small compared with the amount of carbon in harvested timber| which was 30 300 Gg in terms of CO2. 2530,1996,3,2,Greenhouse gas mitigation strategies: Preliminary results from the US Country Studies Program,Under the UN Framework Convention on Climate Change (UNFCCC)| developing and transition countries are eventually required to report greenhouse gas (GHG) emissions inventories and response (mitigation) options. The United States (US) and other donors are providing financial and technical support for climate change country studies to help meet their needs under the UNFCCC. Technical assistance to complete mitigation assessments includes training of analysts| sharing of contemporary tools and assessment techniques| implementation of information-sharing workshops| and an exchange program for analysts. Country analysts have access to more than 25 analytical tools to help them complete their GHG mitigation assessments. Preliminary assessments suggest that GHG stabilization strategies should focus on fossil-fuel combustion| the primary source of carbon dioxide (CO2) emissions| and on forest management to sequester or conserve carbon (C). In selected countries| mitigation of methane (CH4) emissions from rice paddy| livestock production| and waste management are also considered relevant response options. Strengthening of human and institutional capacity to cope with global climate change issues will provide developing and transition countries with a sustained basis for meeting the goals of the UNFCCC. 2500,1996,4,3,Greenhouse warming versus aerosol cooling in the context of global climate change,Since it is doubtless true that the global greenhouse warming may be compensated for by aerosol cooling to a considerable extent| it is important to analyze the reliability of relevant estimates because the assumption of pure scattering aerosols is far from reality. The results of complex CAENEX and GAAREX field programmes conducted in Russia have been considered in this context to demonstrate the significance of aerosol absorption. Also in this context| the case of Arctic haze deserves special attention. Another important aspect is the necessity to take into account the indirect aerosol impact on climate via changes in cloud optical properties. Climate change is a product of interaction between internally generated and externally induced variations. Hence - difficulties involved in early detection of anthropogenic climate signals. A potential methodology for solving such problems has been discussed. Since global climate modelling: is stilt at an early stage of its development| the decisive role belongs to climate observations. Optimization of a Global Climate Observing System (GCOS) with regard to combined use of conventional and satellite observations to solve climate dynamics problems in the context of global change is a must of current climate studies| Various aspects of this optimization have been considered. 4126,1996,2,4,High-temperature tolerance of Artemisia tridentata and Potentilla gracilis under a climate change manipulation,Leaf tolerance to high temperatures| as determined by electrolyte leakage and chlorophyll a fluorescence| was compared for Artemisia tridentata (Asteraceae)| a widespread shrub of the Great Basin| Colorado Plateau| and western slope of the Rocky Mountains| and Potentilla gracilis (Rosaceae)| a herbaceous forb common to high-elevation meadows of the western United States. Species-specific and treatment-specific differences in leaf temperature| high-temperature tolerance and chlorophyll a fluorescence from photosystem II were compared| to test the hypothesis that plants at ecosystem borders will exhibit species-specific responses to climate change. Measurements were made for plants ex posed to a climate change warming manipulation on a major ecosystem border at the Rocky Mountain Biological Laboratory| Colorado| United States| in July and Au gust 1995. In July| daily maximal leaf temperatures were significantly higher for P. gracilis than for A. tridentata. Leaf temperatures were slightly lower in August than July for leaves of both species| on control and heated plots| despite the fact that daily maximum air temperatures were not significantly different for the two months. High-temperature tolerance was determined for leaves treated for 1 h at temperatures ranging from 15 degrees C to 65 degrees C. LT(50) was approximately 46 degrees C for both species on control plots| but was 43 degrees C for leaves of both species from heated plots| contrary to the predictions of the hypothesis. No shift in LT(50) (acclimation) was apparent between July and August. Changes in chlorophyll a fluorescence from photosystem II (F-V/F-M) were used to characterize the photosynthetic response to high temperatures. For both A. tridentata and P. gracilis in July| F-V/F-M was about 0.7| but decreased for temperatures above 40 degrees C. The results suggest that plant responses to global warming at ecosystem borders may be influenced by factors other than leaf-level physiological tolerance to elevated temperatures. 4277,1996,5,4,Holocene evolution of the River Bann estuary and adjacent coast| Northern Ireland,From a variety of published and unpublished geomorphological and stratigraphical information| supported by C-14 dates| an attempt is made to reconstruct the Holocene evolution of the estuary of the River Bann and the adjacent stretch of coastline| Northern Ireland. Submerged and buried peat beds have yielded early Holocene pollen assemblages and C-14 dates that demonstrate a low stand of relative sea-level (RSL) at this time. Feat formation was terminated by the deposition of sands and diatomaceous muds| reflecting RSL rise as a result of both eustatic controls and a declining level of isostatic recovery. Holocene maximum RSL occurred at c. 6000 years sp and reached +2 to +3 m OD (Belfast). A gravel barrier developed at the estuary mouth and provided the anchor point for later aeolian dune development. Along the adjacent coast| basalt shore platforms were either formed or modified| having been within the range of effective wave erosion since the early Holocene. Relative sea-level then fell rapidly. By c. 5500 years sp| aeolian dunes had formed below OD at one site within the estuary. By c. 4000 years sp| the primary elements of the geomorphology of the Bann estuary were in place. Since that time| several phases of aeolian dune and sand sheet development are apparent from the occurrence of buried soils and archaeological materials| but the primary mechanisms controlling dune stability/instability phases are not known with certainty. Periods of temporary supra-elevated water levels| probably resulting from storm conditions| have also been recognized in the coastal sedimentary record; interbedded pear and silty sand with rounded clasts forms part of a terrace sequence at +6 to +8 m OD. Radiocarbon dates suggest that several such events occurred between c. 2300 and 1700 years sp| as pear was accumulating. Recent changes include the construction of estuary mouth training walls and river dredging. Resulting from these activities| aeolian dunes have extended their area| and increased wave erosion within the estuary has been recorded. Human activities and any future RSL rise| consequent upon global warming| seem likely to lead to continuing instability. 4200,1996,3,3,IEA greenhouse gas R&D programme: Full fuel cycle studies,The IEA Greenhouse Gas R&D Programme is an international collaboration supported by 16 countries and several industrial organisations. Its purpose is to evaluate technologies for reducing emissions of greenhouse gases. In the first 3 years of work| the programme concentrated on CO2 emissions from power stations. The main types of power plant and various technologies for capturing CO2 were examined. Storage and utilisation options for CO2 were assessed. The work culminated in the life cycle assessment reported here of 3 fossil fuel based power generation cycles in which CO2 was captured and stored. For each fuel cycle| one natural gas and two coal based| a full 'cradle-to-grave' analysis of emissions was made. A fundamental objective was to establish a consistent and transparent methodology which could form the basis for comparing technical responses to the possibility of global warming. The paper discusses the logic behind the assumptions| and limitations in the data and methodolgy. The uncertainty of much of the data on environmental externalities is recognised and a distinction made between lack of scientific data and the influence of value judgements. External costs that were quantified are small relative to the private costs. 2528,1996,2,3,Impact of freshwater on a subarctic coastal ecosystem under seasonal sea ice (southeastern Hudson Bay| Canada) .1. Interannual variability and predicted global warming influence on river plume dynamics and sea ice,Analysis of sea ice cover| runoff and air temperature observations in Hudson Bay shows marked interannual variability. This variability is thought to play a major role in determining overall productivity of the coastal ecosystem by changes to river plume extent| under-ice light conditions and nutrient levels during spring. Extensive field work off the Great Whale River in southeastern Hudson Bay has shown the importance of freshwater discharge| sea ice cover and meteorological forcing on the production of under-ice microalgae and the success of first feeding in fish larvae. Recent global climate model (GCM) results for a doubling of present atmospheric carbon dioxide indicate increases of both air temperature and precipitation in the Hudson Bay area. Predictions based on GCM results are used to estimate future changes to the sea ice and runoff regime. Sea ice breakup in the offshore is predicted to occur about one month earlier than presently. Estimates of the spring freshet in the Great Whale River indicate it will also advance by approximately one month. Onset of the spring freshet will occur about one month before Hudson Bay ice breakup| similar to present. A predicted reduction of about 35% in maximum sea ice thickness will lead to an increase in the ice-ocean interface irradiance and a decrease in melt water input to the Hudson Bay surface waters. These results are used in a discussion of potential effects of global climate change on northern coastal marine environments. 4252,1996,2,4,Impact of global warming on potato late blight: Risk| yield loss and control,The impact of climate warming on yield losses caused by potato late blight and on the need for disease control was studied by constructing models for timing late blight epidemics and a model of potato growth constrained by late blight. Empirical models predicting the date of planting and emergence of potato were based on thermal time| and a model predicting the date of late blight outbreak was based on thermal time on rainy days. Experiments were conducted over 3 years under ambient and elevated (+3 degrees C) temperatures to obtain parameter values for the growth model. Potato emergence is predicted to occur at 631 degree days accumulated above 0 degrees C after the 16-day running mean temperature in spring exceeds 0 degrees C. A blight outbreak is predicted to occur when the effective temperature sum accumulated above 8 degrees C after potato emergence| on days with at least 0.1 mm of precipitation| achieves 156 degree days. In the prediction of the outbreak the maximum daily accumulation of temperature is limited to 10 degree days. A preliminary sensitivity study carried out at one site in southern Finland suggests that over a range of 1 to 3 degrees C warming| the period during which late blight needs to be controlled by fungicide applications would be 10-20 days longer per 1 degrees C of warming. The increase in yield loss of unprotected crops would be of the same magnitude as the increase in yield potential| around 2 t/ha of dry matter per 1 degrees C of warming. 4280,1996,2,4,Impact of global warming on water resources - Implications for New York City and the New York Metropolitan Region,Global warming effects-and the changes in atmospheric chemistry that produce global warming-may significantly change the demands placed on the water supply and wastewater systems of New York City and the New York Metropolitan Region and these changes may in turn significantly change the demands placed by those systems on regional land use and finances. Given the uncertainties-uncertainties about the nature| magnitude and timing of the changes-global warming sets a profound challenge for public policy: how to initiate and sustain a timely| nonwasteful “adaptive management” response.
4191,1996,2,4,Impact of iceberg scouring on polar benthic habitats,In situ photographs and videos demonstrate that iceberg grounding in both polar regions causes considerable damage to benthic communities. Sessile organisms are eradicated and pioneer species begin to grow in high abundances on the devastated substratum. A preliminary quantitative analysis shows that the sea floor in the Antarctic and Arctic areas of investigation is disturbed by icebergs statistically once every 230 and 53 yr| respectively. Due to the extreme slow growth of many species| particularly in Antarctica| areas frequently disturbed in this manner are likely to be characterised by a continuous natural fluctuation between destruction and recovery. Increased perturbation by iceberg groundings through predicted global warming will result in considerable impairment of this environment. 4258,1996,3,4,Imperata economics and policy,Should policymakers - or anyone else - care about millions of ha of Imperata grasslands? The answer depends on the balance between costs of conversion to other uses and the net benefits produced in economic growth| poverty alleviation| and protection of the environment. The first section on Imperata economics sets up the analytical framework to address this question and draws on the wider development economics literature to consider whether growth and poverty alleviation are conflicting or complementary objectives. Although evidence is limited| it suggests smallholder-based agroforestry could provide the same economic growth with greater poverty alleviation than large-scale forestry estates. There is| however| no substitute for project appraisal for specific settings. The second section on Imperata policy reviews whether policy distortions and market failures provide a sufficient rationale for direct policy intervention to promote tree planting on Imperata grasslands. Estimates of imputed values of carbon sequestration to alleviate global warming are presented for Acacia mangium and rubber agroforestry. The conclusion summarizes the policy research agenda and examines the desirability and feasibility of policy intervention to promote carbon sequestration through Imperata grassland conversion to tree-based systems. 4231,1996,5,4,Implications for the creation of warm saline deep water: Late Paleocene reconstructions and global climate model simulations,A global warming trend began during the late Paleocene that culminated in the early Eocene with the highest global temperatures of the Cenozoic| We have reconstructed late Paleocene surficial boundary conditions and modeled atmospheric conditions using the Goddard Institute for Spate Studies general circulation model version II (GISS GCM II). These experiments were conducted to test the hypothesis that warm saline deep water formed during the late Paleocene and to understand atmospheric circulation near the beginning of a period of global warming. The warming is attributed primarily to increased sea surface temperatures at high latitudes. The sensitivity of the climate to ocean temperature was tested using two sea surface temperature distributions| each delimited latitudinally by oxygen isotope values| but with different east-west gradients. The simulations discussed here contain several features unique among warm climate experiments. The first experiment (P-1) used latitudinally constant (zonal) sea surface temperatures| The zonally distributed sea surface temperatures strengthen the general circulation of the atmosphere. In particular| Hadley Cell circulation is intensified| leading to extremes of precipitation in the equatorial region and extreme evaporation across subtropical oceans| The unusual results prompted a second experiment with modern east-west sea surface temperature gradients superimposed and referred to as P-Gradient (P-Grad). The east-west gradients in the sea surface temperature field exert a strong influence on the general atmospheric circulation| but the extreme zonality prevails| Under extreme zonal conditions it is possible to create a model where evaporation is in excess of precipitation by as much as 3 mm/day. If this occurred in restricted areas in a generally warmer ocean| such as the late Paleocene eastern Tethys Ocean and parts of the South Atlantic Ocean| it should be possible to create very saline water| which could become a component in warm saline deep water formation. 4151,1996,4,4,Implications of a new eddy parameterization for ocean models,A new parameterization of eddies in a coarse resolution ocean model yields deep ocean salinities and temperatures that are significantly closer to observations than with previous parameterizations. This is achieved because dense water is able to flow over sills and into the deep ocean without being diluted with the surrounding water. In addition| the depth to which surface-induced tracers penetrate in the Southern Ocean is now realistic. This depth is overestimated by previous ocean models| including those used to estimate global warming. Adding the new eddy parameterizaton to coupled atmosphere-ocean models is expected to yield greater global warming. 4125,1996,2,4,Implications of vagrant southeastern vireos and warblers in California,All unprecedented influx of vagrant vireos and wood-warblers into California occurred in the spring and summer of 1992. The seven species involved (White-eyed Vireo [Vireo griseus]| Yellow-throated Vireo [V. flavifrons]| Northern Parula [Parula americana]| Yellow-throated Warbler [Dendroica dominica]| Worm-eating Warbler [Helmitheros vermivorus]| Kentucky Warbler [Oporornis formosus]| and Hooded Warbler [Wilsonia citrina]) all breed primarily in the southeastern United States| suggesting a common factor for the influx. Furthermore| all seven species have been recorded in California with increasing frequency over the past two decades| suggesting a common trend in the populations of these species. We examined five hypotheses that could explain the increasing number of California records of these species: (1) observer bias| (2) pesticide-caused misorientation| (3) shifts in winter range| (4) anomalous weather conditions (including global warming and El Nino-Southern Oscillation)| and (5) range expansions into the western United States and/or dramatic population increases in the southeastern United States. We found little or no support for the first three hypotheses. Anomalous weather conditions probably accounted for the magnitude of the 1992 influx| but the final hypothesis is needed to explain the overall trend. Although available data are not sufficient to distinguish between summer distributional shifts and population increases within the ''normal'' breeding ranges of these species| the possibility of westward range expansion is intriguing. 2511,1996,4,4,Improved method of exponential sum fitting of transmissions to describe the absorption of atmospheric gases,For climate modeling and atmospheric research| such as investigations of global climate change| remote sensing of cloud properties| or the missing absorption problem in clouds| it is most important to describe adequately the absorption of radiation by atmospheric gases. An improved method for the exponential sum fitting of transmissions (ESFT) is developed to approximate this absorption accurately. Exponentials are estimated separately for any number of atmospheric-model layers| considering the pressure and temperature dependence of the absorption lines directly. As long as the error of the fit exceeds a limit of tolerance| the number of considered exponential terms is successively increased. The accuracy of the method presented yields a root-mean-square error of less than 0.03% for any atmospheric-model layer| whereas the commonly used one-layer techniques gain errors of up to 3% in the transmission functions for the upper layers. The commonly used ESFT methods consider only one atmospheric layer and introduce the pressure and temperature effects for the other model layers afterwards. 4270,1996,3,3,Incorporating investment uncertainty into greenhouse policy models,Greenhouse gas policy decisions require comprehensive understanding of atmospheric| economic| and social impacts. Many studies have considered the effects of atmospheric uncertainty in global warming| but economic uncertainties have received less analysis. We consider a key component of economic uncertainty: the return on investments in new technologies. Using a mathematical programming model| we show that ignoring uncertainty in technology investment policy may lead to decreases as great as 2 percent in overall expected economic activity in the U.S. with even higher losses in possible future scenarios. These results indicate that both federal and private technology investment policies should be based on models explicitly incorporating uncertainty. 4159,1996,2,4,Increased activity of northern vegetation inferred from atmospheric CO2 measurements,THROUGHOUT the Northern Hemisphere the concentration of atmospheric carbon dioxide rises in winter and declines in summer| mainly in response to the seasonal growth in land vegetation(1-4). In the far north the amplitude of the seasonal cycle| peak to trough| is between 15 and 20 parts per million by volume(5). The annual amplitude diminishes southwards to about 3 p.p.m. near the Equator| owing to the diminishing seasonality of plant activity towards the tropics. In spite of atmospheric mixing processes| enough spatial variability is retained in the seasonal cycle of CO2 to reveal considerable regional detail in seasonal plant activity(6). Here we report that the annual amplitude of the seasonal CO2 cycle has increased by 20%| as measured in Hawaii| and by 40% in the Arctic| since the early 1960s. These increases are accompanied by phase advances of about 7 days during the declining phase of the cycle| suggesting a lengthening of the growing season. In addition| the annual amplitudes show maxima which appear to reflect a sensitivity to global warming episodes that peaked in 1981 and 1990. We propose that the amplitude increases reflect increasing assimilation of CO2 by land plants in response to climate changes accompanying recent rapid increases in temperature. 4266,1996,2,4,Increasing night temperature can reduce seed set and potential yield of tropical rice,The effect of increasing day temperature on reducing seed set in rice is well established| but little is known concerning the impact of increasing night temperature relative to constant day temperature. Recent work suggests that anticipated global warming may be uneven| with a significant increase in night compared to day temperature. Sun-lit| outdoor environment chambers were used to determine the impact of increasing night temperatures at two constant day temperatures (29/21| 29/25| 29/29 degrees C and 33/25| 33/29 and 33/33 degrees C) as well as increasing day/night temperature (29/21| 33/25 and 36/29 degrees C) on growth and yield of rice (cv. IR 72). Increasing day/night temperature to 36/29 degrees C resulted in a significant reduction in both plant biomass and grain yield at harvest. At a constant day temperature of 29 degrees C| increasing night temperature did not significantly alter growth or yield; however| increasing night temperature at a day temperature of 33 degrees C (8 h duration) resulted in a significant decline in grain yield| primarily due to reduced seed set. The decline in grain yield at 33 degrees C with increasing night time temperature was similar to that observed at a day/night temperature of 36/29 degrees C. Data from this experiment suggest that higher night time temperatures per se could increase the susceptibility of rice to sterility with a subsequent reduction in seed set and grain yield. 4108,1996,5,4,Influence of late-Holocene climate on northern Rocky Mountain mammals,An exceptionally rich paleontological site containing thousands of mammalian fossils and well-dated with 18 radiocarbon samples provides evidence of late-Holocene ecological response to climatic change in northern Yellowstone National Park| Wyoming. The mammalian fauna| composed of 10|597 identified specimens| shows surprising affinity to the local habitat with little evidence of long-distance transport of faunal elements| thus revealing the faithfulness of a fossil site to the community from which it is derived. The mammals illustrate ecological sensitivity to a series of mesic to xeric climatic excursions in the sagebrush-grassland ecotone during the past 3200 yr| From 3200 cal yr B.P. to a maximum of 1100 cal yr B.P.| the species composition of mammals indicates wetter conditions than today. Beginning about 1200 cal yr B.P.| the fauna becomes more representative of xeric conditions with maxima in xeric-indicator taxa and minima in mesic-indicator taxa| concordant with the Medieval Warm Period (circa 1000 Co 650 yr B.P.). Cooler| wetter conditions which prevailed for most of the Little Ice Age (700 to 100 yr B.P.) in general correspond to a return to a more mesic mammalian fauna. A warm period within the Little Ice Age is documented by a xeric fauna. These data show that mammalian ecological sensitivity to climatic change over this intermediate time scale holds promise for predictions about the impacts of future global Warming. (C) 1996 University of Washington. 4214,1996,2,4,Influences on formation and dissipation of high arctic fogs during summer and autumn and their interaction with aerosol,Radiosondes established that the air in the near surface mixed layer was very frequently near saturation during the International Arctic Ocean Expedition 1991 which must have been a large factor in the frequent occurrence of fogs. Fogs were divided into groups of summer| transition and winter types depending on whether the advecting air| the ice surface or sea surface respectively was warmest and the source of heat. The probability of summer and transition fogs increased at air temperatures near 0 degrees C while winter fogs had a maximum probability of occurrence at air temperatures between -5 and -10 degrees C. Advection from the open sea was the primary cause of the summer group| the probability of occurrence being high during the Ist day's travel and appreciable until the end of 3 days. Transition fogs reached its maximum probability of formation on the 4th day of advection. Radiation heating and cooling of the ice both appeared to have influenced summer and transition fogs| while winter fogs were strongly Favoured by the long wave radiation loss at clear sky conditions. Another cause of winter fogs was the heat and moisture source of open leads. Wind speed was also a factor in the probability of fog formation| summer and transition fogs being favoured by winds between 2 and 6 ms(-1)| while winter fogs were favoured by wind speeds of only 1 ms(-1). Concentrations of fog drops were generally lower than those of the cloud condensation nuclei active at 0.1%| having a median of 3 cm(-3). While a well-defined modal diameter of 20-25 mu m was found in all fogs| a second transient mode at about 100 mu m was also frequently observed. The observation of fog bows with supernumerary arcs pointed to the existence of fog droplets as large as 200-300 mu m in diameter at fog top. It is suggested that the large drops originated from droplets grown near the fog top and were brought to near the surface by an overturning of the fog layer. Shear induced wave motions and roll vortices were found to cause perturbations in the near-surface layer and appeared to influence fog formation and dissipation. The low observed droplet concentration in fogs limits their ability to modify aerosol number concentrations and size distributions| the persistent overlying stratus being a more likely site for effective interactions. It is suggested that variations in the fog formation described in this paper may be a useful indicator of circulation changes in the arctic consequent upon a global warming. 4197,1996,3,4,Initiatives to respond to climate change concerns,Concerns over the potential impacts of enhanced global warming and climate change have led to a number of initiatives related to anthropogenic emissions of greenhouse gases| notably from the energy sector. The most significant is the UN Framework Convention on Climate Change signed in Rio in 1992. Others include the Climate Technology Initiative| announced at the FCCC Conference of the Parties in Berlin in April 1995 and endorsed by 23 OECD/IEA countries and the European Commission. 4223,1996,2,4,Integrated regional assessment of global climatic change: Lessons from the Mackenzie Basin Impact Study (MBIS),This paper outlines the potential role integrated regional assessments of global climatic change scenarios could play in building better links between science and related policy concerns. The concept is illustrated through description of an ongoing case study from Canada-the Mackenzie Basin Impact Study (MBIS). As part of the Government of Canada's Green Plan| the Global Warming Science Program includes a study of regional impacts of global warming scenarios in the Mackenzie Basin| located in northwestern Canada. The MBIS is a six-year program focussing on potential climate-induced changes in the land and water resource base| and the implications of four scenarios of global climatic change on land use and economic policies in this region. These policy issues include interjurisdictional water management| sustainability of native lifestyles| economic development opportunities (agriculture| forestry| tourism| etc.)| sustainability of ecosystems and infrastructure maintenance. MBIS is due to be completed in 1997. MBIS represents an attempt to address regional impacts by incorporating a ''family of integrators'' into the study framework| and by directly involving stakeholders in planning and research activities. The experience in organizing and carrying out this project may provide some lessons for others interested in organizing regional or country studies. 2538,1996,2,4,Interaction of flooding and salinity stress on baldcypress (Taxodium distichum),Coastal wetlands of the southeastern United States are threatened by increases in flooding and salinity as a result of both natural processes and man-induced hydrologic alterations. Furthermore| global climate change scenarios suggest that| as a consequence of rising sea levels| much larger areas of coastal wetlands may be affected by flooding and salinity in the next 50 to 100 years. In this paper| we review studies designed to improve our ability to predict and ameliorate the impacts of increased flooding and salinity stress on baldcypress (Taxodium distichum (L.) Rich.)| which is a dominant species of many coastal forested wetlands. Specifically| we review studies on species-level responses to flooding and salinity stress| alone and in combination| we summarize two studies on intraspecific variation in response to flooding and salinity stress| we analyze the physiological mechanisms thought to be responsible for the interaction between flooding and salinity stress| and we discuss the implications for coastal wetland loss and the prospects for developing salt-tolerant lines of baldcypress. 4118,1996,2,4,Investigating trends in vegetable crop response to increasing temperature associated with climate change,A thermogradient tunnel| 8.6 m wide and 31.9 m long| generating temperatures ranging from ambient at one end to ambient plus approximately 4 degrees C at the other| was used to assess the potential impact of increased temperatures associated with global warming on the growth of Iceberg lettuce (Lactuca sativa L.)| leek (Allium ampeloprasum L.) and Roscoff cauliflower (Brassica oleracea var. botrytis L.) crops| Optimum mean temperatures for head weight in Iceberg lettuce and trimmed weight in leeks were identified as 12 degrees C and 15.7 degrees C| respectively| corresponding to temperature rises of 2 degrees C and 2.4 degrees C above the average ambient temperature during the experiments. Increased temperatures gave consistently earlier maturity of lettuce| delayed cauliflower curd initiation by up to 49 days and increased the final number of leaves in cauliflower by 36. The implications of these effects are discussed in relation to global warming. 2472,1996,5,4,Isotopic variability in arctic precipitation as a climatic indicator,Preliminary data are examined from a project in which the variability in the isotopic composition of precipitation across northern Canada and the implications for paleoclimatic reconstruction are examined. The data set shows a geographic variability of about 6 parts per thousand in isotopic composition of precipitation across the Canadian Arctic| roughly double the temporal variability seen in the ice core records from the last 10|000 years. The seasonal variability in average monthly delta(18)O values from the arctic stations in 1991 was as much as 26 parts per thousand. A snow and firn core collected on Bylot Island had a range of 14.8 parts per thousand| compared to the range in average monthly precipitation of 25.6 parts per thousand covering the same time period. This difference in the observed seasonal range of values is the result of processes operating in the snow pack| such as vapor movement and molecular diffusion| and the strategy used in sampling the core. The results indicate that a much better understanding of the geographic and seasonal variation in the delta(18)O values of precipitation is required before a direct linkage between the isotope records in ice cores and global climate change can be determined. Using recently developed radiocarbon dating techniques| buried glacier ice that has been preserved in permafrost may be able to provide the greater spatial and temporal detail required. 4181,1996,3,4,Japan's strategy in technology development for mitigating global warming,Japan is a country much concerned with global environmental issues. This paper describes Japan's prospect on energy and CO2 emission|together with prospects of other developed countries. Then the needs for developing long term innovative technologies are demonstrated with a few examples of technologies being developed under MITI R&D program. 2475,1996,3,3,Joint implementation: Biodiversity and greenhouse gas offsets,One of the most pressing environmental issues today is the possibility that projected increases in global emissions of greenhouse gases from increased deforestation| development| and fossil-fuel combustion could significantly alter global climate patterns. Under the terms of the United Nations Framework Convention on Climate Change| signed in Rio de Janeiro during the June 1992 Earth Summit| the United States and other industrialized countries committed to balancing greenhouse gas emissions at 1990 levels in the year 2000. Included in the treaty is a provision titled ''Joint Implementation|'' whereby industrialized countries assist developing countries in jointly modifying long-term emission trends| either through emission reductions or by protecting and enhancing greenhouse gas sinks (carbon sequestration). The US Climate Action Plan| signed by President Clinton in 1993| calls for voluntary climate change mitigation measures by various sectors| and the action plan included a new program| the US Initiative on Joint implementation. Wisconsin Electric decided to invest in a JI project because its concept encourages creative| cost-effective solutions to environmental problems through partnering| international cooperation| and innovation. The project chosen| a forest preservation and management effort in Belize| will sequester more than five million tons of carbon dioxide over a 40-year period| will become economically self-sustaining after ten years| and will have substantial biodiversity benefits. 4224,1996,4,4,Laboratory technique for the measurement of thermal-emission spectra of greenhouse gases: CFC-12,A new technique has been developed to make possible the laboratory study of the infrared-emission spectra of gases of atmospheric interest. The thermal-emission spectra are in local thermodynamic equilibrium|just as they are in the atmosphere| and are not chemiluminescent. Demonstration results obtained by the use of this new technique are presented for dichlorodifluoromethane (CFC-12) at a pressure of 0.5 Torr in a cell with a path length of 5 cm. The measured cell spectra have been compared with simulations with the FASCD3P radiation code. The measurements of the emission spectra of radiatively active gases may be important for the atmospheric greenhouse effect and global warming. (C) 1996 Optical Society of America 2503,1996,4,4,Land use and cover in ecological economics,A basic premise of ecological economics is that the world economy is embedded in and dependent upon Earth's ecosystem. Because land is a basic source of mass and energy throughput in all terrestrial ecosystems| land use and cover represents an integrating element in ecological economics. We have developed a global model that captures this concept. We illustrate this concept's usefulness by showing how global changes in climate| human populations| and international trade policies might affect tropical forests. Results from our scenarios indicate that such changes would likely have adverse effects on the health and integrity of tropical forest ecosystems. Results from our scenarios also indicate that forest depletion in Southeast Asia can be correlated with numerous economic indicators. Whether the correlation with a particular economic variable is positive or negative depends on the global change scenario. This merely reflects the fact that interactions between economic and ecological phenomena are complex. Modeling capabilities can be expanded by adding economic and ecological detail| including more material on throughput| and developing methods for simulating dynamic analyses. 2488,1996,5,4,Late Quaternary sediment dating and quantification of lateral sediment redistribution applying Th-230(ex): A study from the eastern Atlantic sector of the southern ocean,High-resolution records of the natural radionuclide Th-230 were measured in sediments from the eastern Atlantic sector of the Antarctic circumpolar current to obtain a detailed reconstruction of the sedimentation history of this key area for global climate change during the late Quaternary. High-resolution dating rests on the assumption that the Th-230(ex) flux to the sediments is constant. Short periods of drastically increased sediment accumulation rates (up to a factor of 8) were determined in the sediments of the Antarctic zone during the climate optima at the beginning of the Holocene and the isotope stage 5e. By comparing expected and measured accumulation rate of Th-230(ex)| lateral sediment redistribution was quantified and vertical particle rain rates originating from the surface water above were calculated. We show that lateral contributions locally were up to 6.5 times higher than the vertical particle rain rates. At other locations only 15% of the expected vertical particle rain rate were deposited. 4154,1996,5,3,Latest paleocene benthic foraminiferal extinction and environmental changes at Tawanui| New Zealand,A major extinction of intermediate-water (500-1000 m) benthic foraminiferal species coincided with a major decrease in delta(13)C (2.8 parts per thousand) of terrestrial organic matter (n-C-29 alkane) and delta(34)S (20 parts per thousand) of whole rock sulfide in a continuous siltstone sequence in the Tawanui Section (4S degrees S paleolatitude) along the Akitio River| southeastern North Island| New Zealand| in the middle part of the uppermost Paleocene nannofossil zone (CP8). The benthic extinction (25% of species) occurred over similar to 3 kyr at similar to 55.5 Ma. Increases in kaolinite/illite and kaolinite/smectite ratios and in terrestrial organic carbon percentages started similar to 3 kyr before the major benthic extinctions| lasted over similar to 40 kyr| and probably reflect warmer climate and increased rainfall. The productivity of planktonic foraminifera and calcareous nannoplankton decreased similar to 3 kyr prior to the major extinctions and recovered at the time of benthic extinctions. These events that started similar to 3 kyr before the extinction can be best explained by warming| increased rainfall| reduced salinity of surface waters| and increased influence of warm saline deep water (WSDW). Benthic foraminiferal oxygen indices indicate a strong decrease in dissolved oxygen levels within the intermediate water from low oxic (1.5-3.0 mL/L O-2) to suboxic (0.3-1.5 mL/L O-2) conditions coinciding with the benthic extinctions. Increases in total organic carbon (TOC) and in the hydrocarbon-generating potential of kerogen (measured as the hydrogen index (HI)) agree with the interpretation of decreased dissolved oxygen levels of the intermediate water. The lowest oxygen conditions lasted similar to 40 kyr and coincided with a decrease in calcareous benthic foraminiferal productivity| highest TOC levels| and lowest delta(13)C of terrestrial organic carbon. Dominant formation of WSDW or sluggish intermediate-water circulation caused by warming and high rainfall in high-latitude areas most likely led to the 3-kyr time lag between events on land and in surface waters preceeding the extinction and the development of dysaerobia in the sea| coinciding with the major benthic extinction and decrease in delta(13)C and delta(34)S in New Zealand. Global warming of deep and intermediate waters may have caused decomposition of methane hydrate in sediments| resulting in a strongly decreased delta(13)C of marine carbonates| promoting dysaerobia in the ocean| and warming global climate by increased methane concentrations in the atmosphere. Upwelling of WSDW| occurring soon after it became dominant in high-latitude areas| is likely responsible for the recovery of normal salinity and the concomitant recovery of planktonic foraminifera and calcareous nannoplankton productivity in high-latitude surface waters. Minor benthic foraminiferal extinctions (9% of species) occurred similar to 40 kyr after the major extinctions| lasted less than or equal to similar to 6 kyr| and coincided with the initiation of environmental recovery. 2480,1996,2,4,Latitudinal variation in sugar maple fine root respiration,A changing global climate may impact the respiration of fine roots. While many models adjust fine root respiration as temperature increases| the influence of soil nutrient availability and the possibility that root respiration may be adapted to local climate are often not addressed. Rates of fine root respiration were measured in four sugar maple (Acer saccharum Marsh.) forests located along a latitudinal gradient in Michigan. Root respiration was measured as O-2 consumption at temperatures ranging from 6 to 24 degrees C on excised fine root samples in early September| October| and November of 1994. Root respiration increased exponentially with temperature with an average Q(10) of 2.7; there were no differences in Q(10) among sites. However| there were differences among sites in mean respiration rate at a given temperature. This site effect did not indicate ecotypic adaptation to local climate| but rather reflected fine root N concentration. Respiration at a given temperature was consistently higher in roots with higher N concentrations| and higher root N concentrations always occurred at sites having greater N mineralization rates. Results suggest increases in soil temperature could significantly alter root respiration C flux at these sites| as could changes in site N availability associated with chronic N deposition or altered N mineralization resulting from global climate change. 4152,1996,3,3,Lifecycle assessment and economic evaluation of recycling: A case study,Recycling is widely assumed to be environmentally beneficial| although the collection| sorting and processing of materials into new products also entails significant environmental impacts. This study compares the relative environmental impacts of a recycling system (incorporating the kerbside collection of recyclable materials and their subsequent use by manufacturers)| with a waste disposal system (in which the waste is disposed to landfill and primary raw materials are used in manufacture)| using the technique of lifecycle assessment. The methodology is then extended to incorporate an economic evaluation of the environmental impacts. This combination of lifecycle assessment and economic evaluation can be termed 'Lifecycle Evaluation'. Lifecycle assessment quantifies and evaluates the environmental impacts of a product from the acquisition of raw materials| through manufacture and use| to final disposal. Lifecycle assessment can also provide a framework for the analysis of environmental impacts from systems such as transport| or waste management| as demonstrated in this paper. The results| for a case study of Milton Keynes in Central England| show that the recycling system generally performs better than the waste disposal system in terms of contribution to global warming| acidification effects and nutrification of surface water. An alternative method of analysis is then used| in which an economic valuation of the environmental impacts is carried out. This produces net benefits for recycling| per tonne of material| of pound 1769 for aluminium| pound 238 for steel| pound 226 for paper and pound 188 for glass| and net costs of pound 2.57 for high density polyethylene (HDPE)| pound 4.10 for poly (vinyl chloride) (PVC) and pound 7.28 for poly (ethylene terephthalate) (PET). It is concluded that lifecycle evaluation| the combination of lifecycle assessment and economic valuation| can be applied to a variety of waste management issues such as the appraisal of alternative methods of collection for recycling or an examination of the UK waste management hierarchy. This technique allows impacts to be expressed in homogenous units| and the inclusion of social and environmental impacts that would not normally be addressed within a lifecycle assessment. The approach would also facilitate the evaluation of environmental and social effects at a local level| which are particularly crucial to the success of community recycling schemes. Lifecycle evaluation could provide a powerful tool to aid the development of sustainable waste management and recycling policy. 2534,1996,2,3,Long-term effects of a doubled atmospheric CO2 concentration on the CAM species Agave deserti,To examine the effects of a doubled atmospheric CO2 concentration and other aspects of global climate change on a common CAM species native to the Sonoran Desert| Agave deserti was grown under 370 and 750 mu mol CO2 mol(-1) air and gas exchange was measured under various environmental conditions. Doubling the CO2 concentration increased daily net CO2 uptake by 49% throughout the 17 months and decreased daily transpiration by 24%| leading to a 110% increase in water-use efficiency| Under the doubled CO2 concentration| the activity of ribulose-1|5-bisphosphate carboxylase/oxygenase (Rubisco) was 11% lower| phosphoenolpyruvate carboxylase was 34% lower| and the activated:total ratio for Rubisco was 25% greater than under the current CO2 concentration. Less leaf epicuticular wax occurred on plants under the doubled CO2 concentration| which decreased the reflectance of photosynthetic photon flux (PPF); the chlorophyll content per unit leaf area was also less| The enhancement of daily net CO2 uptake by doubling the CO2 concentration increased when the PPF was decreased below 25 mol m(-2) d(-1)| when water was withheld| and when day/night temperatures were below 17/12 degrees C| More leaves| each with a greater surface area| were produced per plant under the doubled CO2 concentration. The combination of increased total leaf surface area and increased daily net CO2 uptake led to an 88% stimulation of dry mass accumulation under the doubled CO2 concentration| A rising atmospheric CO2 concentration| together with accompanying changes in temperature| precipitation| and PPF| should increase growth and productivity of native populations of A. deserti. 2481,1996,2,4,Long-term trends and interannual variability in tropical cyclone activity over the western North Pacific,While Landsea et al. (1996) show that the number of intense Atlantic hurricanes is on the decrease| the trend of tropical cyclone activity over the western North Pacific is found to be just the opposite. For the period 1959 to 1994| the number of tropical storms and typhoons went through a period of decrease and then an increase| showing an obvious second-order variation such that the activity has been on a generally upward trend since the late 1980s. A similar trend is found for the number of typhoons. All these time tendencies are statistically significant. In addition to a trend| shorter-term oscillations of two| five and seven years can also be identified after the trend is removed. 4225,1996,2,4,Malaria transmission and climate change in Australia,Although endemic malaria was eradicated from Australia by 1981| the vectors remain and transmission from imported cases still occurs. Climate modelling shows that global warming will enlarge the potential range of the main vector| Anopheles farauti sensu stricto; by the year 2030 it could extend along the Queensland coast to Gladstone| 800 km south of ifs present limit. Vigilance and a dispassionate assessment of risk are needed to meet this challenge.
4285,1996,3,3,Measurement method of the absorption fixation quantity of carbon dioxide by Water Hyacinth,As is well known| greenhouse-effect gases causes serious global warming| and it is very important problem for the 21st century. The authors observed the greenhouse-effect of carbon dioxide| whose contribution ratio to warming is most high. Now the concentration of carbon dioxide is presently approximately 350 ppm| and is estimated to become 400 ppm in the year 2000. An absorption-fixation method was applied photosynthesis by Water Hyacinth an aquatic plant. Also| an apparatus was developed that can accurately measure the concentration of carbon dioxide. The authors suggest a plant-cultivating apparatus whose temperature| humidity and illumination can be controlled| and maintains the interior of the cultivating room at constant conditions| for growing Water Hyacinth. A continuous 24-hours measurement was carried out of carbon dioxide in the cultivating apparatus using a gas chromatograph with an auto sampler. We could accurately measure the carbon dioxide concentration in plant cultivating apparatus using this apparatus. 4238,1996,4,4,Measurement of tropospheric ozone by thermal emission spectroscopy,A new technique has been developed for the remote sensing of tropospheric ozone. In this technique the thermal radiation from ozone is measured against the cold background blackbody emission of clouds using ground-based FTIR spectroscopy. Preliminary measurements obtained in the springtime at Peterborough| Ontario| using this hew technique| have indicated an average tropospheric ozone mixing ratio of 50 +/- 7 ppbv within a 2.7 km layer from the surface for air flowing from a heavily industrialized and highly urbanized region. Ozone concentrations of this magnitude are in accordance with the amounts obtained for moderately polluted| springtime air using traditional in situ measurement techniques. The greenhouse radiation flux associated with this amount of ozone was estimated to be 0.61 Wm(-2) +/- 13%. Since there are few techniques available for the remote sensing of tropospheric air pollutants| this new technique could be a potentially valuable development. 2521,1996,4,4,Methods for assessing public health vulnerability to global climate change,Assessment of the human health risk posed by global climate change presents a new challenge to public health professionals. In contrast to conventional toxicological risk assessment| the health risk assessment related to global climate change must analyze stressors that consist of complex interrelated climate factors and risks that are mediated through intermediate species in varying ecosystems. A framework for ecologically based human health risk assessment helps distinguish the concepts of global climate change risk assessment from conventional risk assessment. Specific methods for linking climate variables with human disease include historical analysis of climate and disease data and the development of integrated mathematical models. Two historical climate-disease studies of malaria in Africa provide a starting point for further analysis. Early approaches to evaluating the human health risks from global climate change will include simple mapping of disease boundaries and climate factors. Computer-based geographical information system (GIS) technology will assist in the organization and analysis of climate| environment and disease data. Ultimately| complex integrated mathematical models may provide quantitative estimates of risk| but these models have not yet been validated. The collection of geographically organized relevant data through either field work or remote sensing technology will both help validate comprehensive integrated models and enhance our understanding of the associations between climate change and human health. 2519,1996,4,4,Methyl bromide: Ocean sources| ocean sinks| and climate sensitivity,The oceans play an important role in the geochemical cycle of methyl bromide (CH3Br)| the major carrier of O-3-destroying bromine to the stratosphere. The quantity of CH3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources| The production mechanism is unknown but may be biological. Most of this CH3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmosphere is poorly constrained; measurements in seawater and the atmosphere have been used to justify both a large oceanic CH3Br flux to the atmosphere and a small net ocean sink| Since the consumption reactions are extremely temperature-sensitive| small temperature variations have large effects on the CH3Br concentration in seawater| and therefore on the exchange between the atmosphere and the ocean| The net CH3Br flux is also sensitive to variations in the rate of CH3Br production. We have quantified these effects using a simple steady state mass balance model| When CH3Br production rates are linearly scaled with seawater chlorophyll content| this model reproduces the latitudinal variations in marine CH3Br concentrations observed in the east Pacific Ocean by Singh et al. [1983] and by Lobert et al. [1995]| The apparent correlation of CH3Br production with primary production explains the discrepancies between the two observational studies| strengthening recent suggestions that the open ocean is a small net sink for atmospheric CH3Br| rather than a large net source. The Southern Ocean is implicated as a possible large net source of CH3Br to the atmosphere. Since our model indicates that both the direction and magnitude of CH3Br exchange between the atmosphere and ocean are extremely sensitive to temperature and marine productivity| and since the rate of CH3Br production in the oceans is comparable to the rate at which this compound is introduced to the atmosphere| even small perturbations to temperature or productivity can modify atmospheric CH3Br. Therefore atmospheric CH3Br should be sensitive to climate conditions. Our modeling indicates that climate-induced CH3Br variations can be larger than those resulting from small (+/- 25%) changes in the anthropogenic source| assuming that this source comprises less than half of all inputs. Future measurements of marine CH3Br| temperature| and primary production should be combined with such models to determine the relationship between marine biological activity and CH3Br production. Better understanding of the biological term is especially important to assess the importance of non anthropogenic sources to stratospheric ozone loss and the sensitivity of these sources to global climate change. 4217,1996,5,3,Mid-Pliocene warmth: Stronger greenhouse and stronger conveyor,Three million years ago| prior to the onset of northern hemisphere glaciation| global mean temperatures may have been as much as 3.5 degrees C warmer than at present. We present evidence| based on the carbon isotopic composition of marine organic matter| that atmospheric CO2 levels at this time were on average only about 35% higher than the preindustrial value of 280 ppm. We also present carbon isotopic evidence for stronger thermohaline circulation in the Atlantic Ocean during the warmest intervals and propose that the North Atlantic ''conveyor belt'' may act as a positive feedback to global warming by enhancing sea ice retreat and decreasing high latitude albedo. Based on our results| it seems unlikely that the mid Pliocene warm period was a doubled CO2 world. 2520,1996,5,3,Middle to late Paleozoic atmospheric CO2 levels from soil carbonate and organic matter,The stable carbon isotope compositions of ancient soil carbonate and coexisting soil organic matter indicate that atmospheric CO2 levels decreased by a factor of 10 during the middle to late Paleozoic era. Proxy measurements of CO2 were made by application of a soil carbonate CO2 paleobarometer to a suite of paleosols that share key physical and chemical characteristics. The estimates agree with theoretical models that imply that a decrease in Paleozoic atmospheric CO2 levels was associated with afforestation of the land surface by terrestrial plants and with global climate change leading to the extensive Permo-Carboniferous glaciation. 4135,1996,3,3,Mitigation alternatives to decrease nitrous oxides emissions and urea-nitrogen loss and their effect on methane flux,Nitrous oxide (N2O) and methane (CH4) are greenhouse gases that are contributing to global warming potential. Nitrogen (N) fertilizer is one of the most important sources of anthropogenic N2O emissions. A field study was conducted to compare N-use efficiency and effect on N2O and CH4 flux| of urea| urea plus the nitrification inhibitor dicyandiamide (U + DCD)| and a control release fertilizer| polyolefin coated urea (POCU) in irrigated spring barley (Hordeum vulgare L.) in northeastern Colorado. Each treatment received 90 kg urea-N ha(-1) and microplots labeled with N-15-fertilizer were established. Average N2O emissions were 4.5| 5.2| 6.9| and 8.2 g N ha(-1) d(-1) for control| U + DCD| POCU| and urea| respectively. During the initial 21 d after fertilization| N2O emissions were reduced by 82 and 71% in the U + DCD and POCU treatments| respectively| but continued release of N fertilizer from POCU maintained higher N2O emissions through the remainder of the growing season. No treatment effect on CH4 oxidation in soils was observed. Fertilizer N-15 found 50 to 110 cm below the soil surface was lower in the POCU and U + DCD treatments. At harvest| recovery of N-15-fertilizer in the plant-soil system was 98| 90| and 85% from POCU| urea| and U + DCD| respectively. Grain yield was 2.2| 2.5| and 2.7 Mg ha(-1) for POCU| urea| and U + DCD| respectively. Dicyandiamide and POCU showed the potential to be used as mitigation alternatives to decrease N2O emissions from N fertilizer and movement of N out of the root zone| but N release from POCU does need to be formulated to better match crop growth demands. 4193,1996,4,2,Model estimates of nitrous oxide emissions from agricultural lands in the United States,The Denitrification-Decomposition (DNDC) model was used to elucidate the role of climate| soil properties| and farming practices in determining spatial and temporal variations in the production and emission of nitrous oxide (N2O) from agriculture in the United States. Sensitivity studies documented possible causes of annual variability in N2O flux for a simulated Iowa corn-growing soil. The 37 scenarios tested indicated that soil tillage and nitrate pollution in rainfall may be especially significant anthropogenic factors which have increased N2O emissions from soils in the United States. Feedbacks to climate change and biogeochemical manipulation of agricultural soil reflect complex interactions between the nitrogen and carbon cycles. A 20% increase in annual average temperature in degrees C produced a 33% increase in N2O emissions. Manure applications to Iowa corn crops enhanced carbon storage in soils| but also increased N2O emissions. A DNDC simulation of annual N2O emissions from all crop and pasture lands in the United States indicated that the value lies in the range 0.9 - 1.2 TgN. Soil tillage and fertilizer use were the most important farming practices contributing to enhanced N2O emissions at the national scale. Soil organic matter and climate variables were the primary determinants of spatial variability in N2O emissions. Our results suggest that the United States Government| and possibly the Intergovernmental Panel on Climatic Change (IPCC)| have underestimated the importance of agriculture as a national and global source of atmospheric N2O. The coupled nature of the nitrogen and carbon cycles in soils results in complex feedbacks which complicate the formulation of strategies to reduce the global warming potential of greenhouse gas emissions from agriculture. 2483,1996,2,3,Modeling potential changes of forest area in Thailand under climate change,The forest cover of Thailand has been characterized according to the Holdridge Life Zone Classification| a model that correlates climatic features with vegetation distribution Six Holdridge life zone types of forest cover are found in Thailand: subtropical dry forest| subtropical moist forest| subtropical wet forest| tropical dry forest| tropical moist forest| and tropical wet forest. Climate change scenarios were simulated by three general circulation models: two United Kingdom Meteorological Office models (the low and high resolution versions) and the Goddard Institute for Space Studies model. These scenarios were used to simulate the effects of future climate change on Thai forests. The ratios of precipitation and the absolute values of temperature changes were incorporated into a baseline climate scenario from the International Institute of Applied Systems Analysis. Under the climate change scenarios simulated by the three general circulation models| the subtropical dry forest could potentially disappear| and areas of tropical very dry forest would appear. In general| the area of subtropical life zone would decline from about 50% to 20%-12% of total cover| whereas the tropical life zone would expand its cover from 45% to 80%. All three general circulation model scenarios suggest that the tropical dry forest has the greatest potential to extend into the subtropical moist forest. This analysis suggests that global climate change would have a profound effect on the future distribution and health of Thai forests. 4267,1996,3,3,Modelling greenhouse gas emissions from cars in Great Britain,This paper outlines the issues involved in the problem of global warming. The road transport sector's contributions to this problem are then detailed and various policy options to reduce greenhouse gas emissions from private cars are discussed. The paper then describes a model which forecasts greenhouse gas emissions from cars. The effects of various policy options are then modelled and the results compared. Policies considered include: raising fuel prices in terms of the UK government's commitment to increase road fuel duties; subsidising public transport in terms of reduced public transport fares; and a tax differentiated by engine size. 2513,1996,2,4,Monosoonal precipitation responses of shrubs in a cold desert community on the Colorado Plateau,South-eastern Utah forms a northern border for the region currently influenced by the Arizona monosoonal system| which feeds moisture and summer precipitation into western North America. One major consequence predicted by global climate change scenarios is an intensification of monosoonal (summer) precipitation in the aridland areas of the western United States. We examined the capacity of dominant perennial shrubs in a Colorado Plateau cold desert ecosystem of southern Utah| United States| to use summer moisture inputs. We simulated increases of 25 and 50 mm summer rain events on Atriplex canescens| Artemisia filifolia| Chrysothamus nauseosus| Coleogyne ramosissima| and Vanclevea stylosa| in July and September with an isotopically enriched water (enriched in deuterium but not O-18). The uptake of this artificial water source was estimated by analyzing hydrogen and oxygen isotope ratios of stem water. The predawn and midday xylem water potentials and foliar carbon isotope discrimination were measured to estimate changes in water status and water-use efficiency. At. canescens and Ch. nauseosus showed little if any uptake of summer rains in either July or September. The predawn and midday xylem water potentials for control and treatment plants of these two species were not significantly different from each other. For A. filifolia and V. stylosa| up to 50% of xylem water was from the simulated summer rain| but the predawn and midday xylem water potentials were not significantly affected by the additional summer moisture input. In contrast| C. ramosissima showed significant uptake of the simulated summer rain (>50% of xylem water was from the artificial summer rain) and an increase in both predawn and midday water potentials. The percent uptake of simulated summer rain was greater when those rains were applied in September than in July| implying that high soil temperature in midsummer may in some way inhibit water uptake. Foliar carbon isotope discrimination increased significantly in the three shrubs taking up simulated summer rain| but pre-treatment differences in the absolute discrimination values were maintained among species. The ecological implications of our results are discussed in terms of the dynamics of this desert community in response to changes in the frequency and dependability of summer rains that might be associated with a northward shift in the Arizona monsoon boundary. 2514,1996,3,3,Multisector economic models for analyzing global climate change,Economics plays a major role in global climate change. Economic models can therefore prove invaluable in understanding the potential of human activity to damage the ecosystem and in designing policies to remedy rhe situation. The purpose of this paper is to describe a set of economic tools| referred to as Multisector Economic Models| and to illustrate their usefulness by applying them to important issues in global climate ch.ange research. There are two major reasons we have chosen to focus on multisector economic models. First| economic activity generates the vast majority of greenhouse gases (GHG:;). Hence| we need models that can depict the creanon and emission of these pollu- tants and their impacts on the natural world. Ideally| models would include feedback effects as well in terms of the reduction in the quantity and quality of resource and environmental stocks. Useful models would also be able ‘to reflect the key role of technology both in generating GHGs and for their mitigation. These models should also be able to incorporate the rapidly changing nature of technology.
4213,1996,4,3,Needle| crown| stem| and root phytomass of Pinus sylvestris stands in Russia,With growing| concern about predicted global warming| increasing attention is being paid to the phytomass (living plant mass) components of forest stands and their role in the carbon cycle. The ability to predict phytomass components from commonly available inventory data would facilitate our understanding of the latter. We focus on Scots pine (Pinus sylvestris L.) stands in Russia| with the objective of predicting stand phytomass (Mg ha(-1)) for the four major stand components: needles| crown| stems| and roots| The study area includes regions in Russia where Scots pine is a stand-forming species: from European Russia (33 degrees E) to Yakutia (130 degrees E) in eastern Siberia. To ensure that results will be widely applicable| only variables consistently measured in forest inventories were considered as possible predictors: stand age| site quality class| and stocking (stand stem volume with bark| m(3) ha(-1)). Stand phytomass data were obtained from numerous regional and local phytomass studies| and supplemented with additional unpublished data. This is the first comprehensive study synthesizing stand level phytomass relations for P. sylvestris for most of its range in Russia. The combined results from over 18 regional and local phytomass studies provide a level of generality that is not possible with individual local studies. In addition to estimating stand phytomass components across a wide range of conditions| these phytomass models can also be used to verify carbon allocation rules in process-based models. 4179,1996,3,2,New feasibility study of carbon dioxide production from coal-fired power plants for enhanced oil recovery: A Canadian perspective,The concept of capturing carbon dioxide from coal-fired power plants and utilizing it as a flooding agent for enhanced oil recovery (EOR) processes is currently drawing much interest from oil| utility and coal companies in Western Canada. Implementation of such a scheme would provide two important benefits: (i) the captured CO2 could be marketed as a flooding agent which would generate revenues| and (ii) CO2 emissions to the atmosphere would be reduced. Since CO2 emissions are considered to be the main contributor to the possible serious environmental problem of global warming| the proposed scheme could become an important instrument to reduce such emissions at minimal incremental cost to the environment. This paper demonstrates how cogeneration concepts| together with process optimization strategies| help to reduce the CO2 production cost by utilizing low-pressure steam and waste heat from various sections of the power generation process. Based on these concepts and strategies| results from this study show that the recovery cost of CO2 from a coal-fired power plant can range between $0.50-2.00/mscf. If the cost is approximately $1.25/mscf| the production cost of a barrel of incremental oil would be less than $12. Therefore| even at today's modest oil prices| there is room for profit to be made operating a CO2 flood with flue gas extracted CO2. The technical and economical feasibility of the concepts are evaluated and the practical implications for the Canadian resources are discussed. 4173,1996,3,4,New| long term alternative fluorosolvents for electronics cleaning & drying applications,For years| CFC-113-based cleaning agents and displacement drying fluids were the cornerstone of the electronics industry. CFC-113 based cleaners were used in all applications| especially when reliability and field performance was paramount. Similarly| CFC-113 based displacement drying fluids| originally developed to provide post-plated scratch and spot-free surfaces in the jewellery industry| were used in many printed wiring board shops after electroless copper plating. Instead of heated air drying that oxidized the copper| which then required pumice scrubbing prior to photo-polymer primary imaging film lamination| PWBs were water rinsed| CFC-113 displacement dried in an oxygen-free environment and then went straight to yellow room for film lamination. Since the pumice scrubbing step was eliminated| less copper had to be plated onto the PWBs| which cut down on cycle time. In addition| the process was capable of drying even the thickest multilayer via holes quickly and completely. Many of our components cannot be exposed to water| and thus required solvent cleaning. All the testing for hermeticity is normally accomplished with PerFluoroCarbons (PFCs)| which are under scrutiny as global warming gases. Today we have a new wave of environmentally preferred fluorosolvents to fill the void left by the Montreal Protocol mandated production shut-down of CFC-113. These solvents include both the HydroChloroFluoroCarbons (such as NCFC-225) and the HydroFluoroCarbons (HFCs)| a new class of materials characterized by incorporating hydrogen| fluorine and carbon (but no other halogens| however they may incorporate other elements)| possessing zero ozone depleting potentials| short atmospheric life-times and minimal global warming potential. This paper explains the development commercialization and qualification of these new highly fluorinated compounds| using their physical and chemical properties to predict where they might best serve the needs of the component| printed board fabrication and assembly sectors of the electronics industry in the same way as their CFC-113 counterparts| thus allowing manufacturing to continue to keep pace with the creativity of the design community. 4169,1996,3,3,Nitrous oxide and carbon dioxide fluxes from a bare soil using a micrometeorological approach,Increasing atmospheric carbon dioxide (CO2) and nitrous oxide (N2O) levels have prompted research on management of the soil C and N pools. The impact of C and N fertilizer addition on N2O and CO2 field emissions is not clear. We determined N2O and CO2 fluxes from a 1-ha bare soil plot using micrometeorological methods with the objective of evaluating the effect of management practices (cultivation| irrigation| fertilizer| and sucrose applications) on the relative importance of both trace gases. Research was conducted at the flora Research Station (Typic Hapludalf) in Ontario| Canada| over 7 mo. The N2O concentration gradients were measured using a Tunable Diode Laser Trace Gas Analyzer and the CO2 gradients using an Infra-Red Gas Analyzer. The transport coefficients were calculated using a Bowen Ratio Energy Balance and two wind profile approaches. These three approaches resulted in similar hourly fluxes. Daily N2O fluxes for nonevent periods were 12 ng m(-2) s(-1) in 1991| and 2 ng m(-2) s(-1) in the summer of 1992| while CO2 fluxes before treatments in 1991 were 0.18 mg m(-2) s(-1). Sucrose addition (420 kg C ha(-1)) resulted in the highest N2O and CO2 daily emissions measured during the experiment at 3100 ng m(-2) s(-1) and 0.5 mg m(-2) s(-1)| respectively. Peak emissions of 250 ng N2O m(-2) s(-1) were measured after wetting of dry soil (WFP < 0.4) through irrigation in 1991| and rain in 1992| Application of ammonium sulfate (100 kg N ha(-1)) and irrigation increased N2O emissions to 75 ng m(-2) s(-1)| with a smaller effect caused by two subsequent irrigations on wet soil (WFP > 0.6). Carbon dioxide fluxes varied between 0.01 and 0.5 mg m(-2) s(-1) being the predominant gas contributing to an equivalent CO2 global-warming potential| but addition of sucrose increased the contribution of N2O to twice the contribution of CO2. The combined effect of C and N additions (e.g. manure and legume) on the N2O emissions in irrigated or high rainfall areas should be considered in the efforts of atmospheric C sequestering. 4164,1996,2,3,Nitrous oxide emission by nitrification and denitrification in different soil types and at different soil moisture contents and temperatures,Nitrous oxide is produced from denitrification and nitrification processes in soils| and contributes to global warming and stratospheric ozone depletion. Laboratory experiments with six soils ranging in clay content between 4-12% were designed to investigate the effect of water and temperature on the partitioning of N2O from denitrification and nitrification. The nitrification rates at 70% field capacity (FC) were significantly higher in the loamy soils (980-1440 mu g N kg(-1) soil day(-1)) than in the sandy soils (60-460 mu g N kg(-1) soil day(-1) ). The nitrous oxide produced by nitrification differed similarly between the soil types resulting in ratios of N2O-N relative to NO3--N| which were only ranging from 0.28 to 0.48% with an average of 0.39%| indicating a rather constant relationship between nitrifrcation and nitrous oxide emission. Maximum nitrification rates occured at 20 degrees C and 100% fired capacity (FC) and was 1/3 at 40% FC. At lower temperatures only small responses to changes in soil moisture were observed. The percentage of N2O-N produced by nitrification increased with increasing soil moisture (0.49% at 40% FC and 0.93% at 100% FC) and decreased with increasing temperature (0.49% at 5 degrees C and 0.17% at 20 degrees C). The denitrification activity (N-2 + N2O) in the sandy loam soil responded significantly to both increased soil moisture and increased temperature| whereas the coarse sandy soil only reacted to increased temperature. In the coarse sandy soil the Q(10)-values were in the range from 1.9 to 3.4| and the values were ranging from 4.9 to 8.9 in the sandy loam soil. As for the denitrification activity also the N-2 to N2O ratio increased exponentially with increasing temperature| which implies a linear relationship between the Iog(N-2 to N2O ratio) and the temperature. The N-2 to N2O ratios were lower in the coarse sandy soil than in the sandy loam soil| and were in the range from 0 to 16. 2533,1996,2,4,Northern agriculture: Constraints and responses to global climate change,In the northern circumpolar zone| the area between the 600 degrees Cd and 1200 degrees Cd isopleths of effective temperature sum above 5 degrees C| the annual receipt of solar energy is limited by the low angle of radiation arriving at the earth's surface. This is the primary cause of the climatic constraints observed in the zone| such as low temperatures| a short growing season| frosts during the growing season| long and cold winters and thick snow cover. In Finland| the length of the growing season varies from 180 days in the south (60 degrees N) to 120 days in the north (70 degrees N). Consequently| the growing time for crops from sowing to ripening is also short| which limits their ability to produce high yields. The most advanced forms of farming in the high-latitude zone are encountered towards the south in Northern Europe| central Siberia and the prairies of Canada| i.e. mainly in the phytogeographical hemiboreal zone where the effective temperature sum is higher than 1200 degrees Cd. Conditions for agriculture then deteriorate gradually further north with the cooling of the climate| and this is reflected as an increase in cattle rearing at the expense of grain cultivation. In northern Europe farming is practised as far north as to the Arctic Circle| at about 66 degrees N latitude. In North America| fields extend to about 55 degrees N. In Asia| there are few fields north of 60 degrees N. Finland is the most northern agricultural country in the world| with all its field area| about 2.5 million hectares| located north of latitude 60 degrees N. Changes in the climate and atmospheric CO2 predicted for the future are likely to have a strong influence| either beneficial or disadvantageous| on the conditions for growth in northern areas where the annual mean temperature is 5 degrees C or less. 4148,1996,3,3,Nuclear energy into the twenty-first century,The historical development of the civil nuclear power generation industry is examined in the light of the need to meet conflicting energy-supply and environmental pressures over recent decades. It is suggested that fission (thermal and fast) reactors will dominate the market up to the period 2010-2030| with fusion being relegated to the latter part of the twenty-first century. A number of issues affecting the use of nuclear electricity generation in Western Europe are considered including its cost| industrial strategy needs| and the public acceptability of nuclear power| The contribution of nuclear power stations to achieving CO2 targets aimed at relieving global warming is discussed in the context of alternative strategies for sustainable development| including renewable energy sources and energy-efficiency measures| Trends in the generation of nuclear electricity from fission reactors are finally considered in terms of the main geopolitical groupings that make up the world in the mid-1990s. Several recent| but somewhat conflicting| forecasts of the role of nuclear power in the fuel mix to about 2020 are reviewed. It is argued that the only major expansion in generating capacity will take place on the Asia-Pacific Rim and not in the developing countries generally. Nevertheless| the global nuclear industry overall will continue to be dominated by a small number of large nuclear electricity generating countries; principally the USA| France and Japan. Copyright (C) 1996 Elsevier Science Ltd 4157,1996,3,4,Numerical study on effects of hydrate formation on deep sea CO2 storage,When liquid CO2 is disposed into the deep sea or stored on tile sea floor in order to prevent anthropogenic CO2 from entering the atmosphere| the CO2 reacts immediately with the seawater and forms solid CO2 hydrate| In this study| growth model is proposed for CO2 hydrate layers. In addition| an estimation is shown for the CO2 concentration profile| the growth rate of the leger| and its thickness in the quasi-steady state| The simulation results indicate that the hydrate layer diminishes CO2 dissolution from the storage pool into the upper sea. This growth process is extremely sensitive to the density difference between the CO2 hydrate particles and its environmental liquid. 4105,1996,4,3,Oceanic carbon dioxide uptake in a model of century-scale global warming,In a model of ocean-atmosphere interaction that excluded biological processes| the oceanic uptake of atmospheric carbon dioxide (CO2) was substantially reduced in scenarios involving global warming relative to control scenarios. The primary reason for the reduced uptake was the weakening or collapse of the ocean thermohaline circulation. Such a large reduction in this ocean uptake would have a major impact on the future growth rate of atmospheric CO2. Model simulations that include a simple representation of biological processes show a potentially large offsetting effect resulting from the downward flux of biogenic carbon. However| the magnitude of the offset is difficult to quantify with present knowledge. 4278,1996,2,3,Overwintering of winter cereals in Hungary in the case of global warming,Under phytotronic conditions investigations were made on the effect of important environmental factors| such as temperature| water and an increasing concentration of atmospheric CO2| on the hardening of young cereal plants. In all the varieties derived from the major wheat growing regions of the world the hardening process was favourably influenced by a doubling of atmospheric CO2 content| so that a significantly larger number of plants survived the frost test than for plants of the same variety raised under normal conditions. A reduction in freezing temperature and an increase in soil moisture content caused a slight reduction in survival % for varieties with excellent frost resistance and a great reduction for those with medium or poor frost resistance. Predictions suggest that in Central Europe| as the result of global climatic changes| there will be a reduction in the quantity of winter precipitation| a considerable rise in winter temperatures and an increase in atmospheric CO2 concentration. Judging by the experimental results| these changes could improve the overwintering of winter cereals; at the same time| however| a number of factors (mainly the reduction of precipitation) leading to yield losses must be expected during the vegetation period. 4209,1996,2,4,Overwintering strategies of mosquitoes (Diptera: Culicidae) on warmer islands may predict impact of global warming on Kyushu| Japan,Mosquito overwintering was studied on Tanegashima and Yakushima| islands south of Kyushu| to predict the impact of global warming on northern Kyushu where mosquitoes overwinter in diapause. On Tanegashima and Yakushima| the following 5 types of overwintering strategies were recognized: (1) continued reproduction without diapause (2 Anopheles spp.| 2 Culex spp.| 2 Aedes spp.); (2) diapausing female adults but a few adults from late-developing larvae may emerge in midwinter (2 Anopheles spp. and 9 Culex spp.); (3) diapausing eggs but a few adults may emerge in midwinter (5 Aedes spp.); (4) diapausing larvae (1 Orthopodomyia sp.| 1 Aedes sp.| 1 Armigeres sp.| 1 Uranotaenia sp.| 1 Toxorhynchites sp.); and (5) diapausing eggs and larvae (1 Tripteroides sp.). Few females of 4 aedine species were collected while seeking hosts in midwinter| but neither larvae nor adults of Culex tritaeniorhynchus Giles or southern house mosquito| Culex quinquefasciatus Say| were found during this survey. The 5 degrees C increase in the midwinter mean temperature in northern Kyushu probably will not produce serious mosquito problems directly| but the proximity of the subtropical regions may have significant effects through dispersal of adult mosquitoes. 4136,1996,2,3,PAGE95 - An updated valuation of the impacts of global warming,A vital measure for global warming policy is the marginal impact of a tonne of carbon emitted to the atmosphere. In economic terms| this value corresponds to the carbon tax level needed to internalize the externalities associated with climate change. This study re-evaluates the marginal impact of CO2 emissions in the light of new scientific and economic understanding of the cooling effects of sulphate aerosols and ozone depletion| the regional distribution of global warming damages| non-linearity in damage as a function of temperature rise and the appropriate discount rate. Copyright (C) 1996 Elsevier Science Ltd. 4236,1996,5,3,Paleoclimate data constraints on climate sensitivity: The paleocalibration method,The relationship between paleoclimates and the future climate| while not as simple as implied in the 'paleoanalog' studies of Budyko and others| nevertheless provides sufficient constraints to broadly confirm the climate sensitivity range of theoretical models and perhaps eventually narrow the model-derived uncertainties. We use a new technique called 'paleocalibration' to calculate the ratio of temperature response to forcing on a global mean scale for three key intervals of Earth history. By examining surface conditions reconstructed from geologic data for the Last Glacial Maximum| the middle Cretaceous and the early Eocene| we can estimate the equilibrium climate sensitivity to radiative forcing changes for different extreme climates. We find that the ratios for these three periods| within error bounds| all lie in the range obtained from general circulation models: 2-5 K global warming for doubled atmospheric carbon dioxide. Paleocalibration thus provides a data-based confirmation of theoretically calculated climate sensitivity. However| when compared with paleodata on regional scales| the models show less agreeement with data. For example| our GCM simulation of the early Eocene fails to obtain the temperature contrasts between the Equator and the Poles (and between land and ocean areas) indicated by the data| even though it agrees with the temperature data in the global average. Similar results have been reported by others for the Cretaceous and for the Last Glacial Maximum. 4186,1996,5,4,Paleoclimatic implications of Holocene lake-level fluctuations| Owasco lake| New York,Radiocarbon-controlled stratigraphic data from Owasco Lake valley| New York| document two cycles of relative lake-level change during the Holocene in response to regional variations in effective precipitation. Lake highstands occurred at 10.5 and 6.9 ka| with an intervening lowstand at 9 ka. The 10.5 ka highstand occurred during the well-known Killarney-Younger Dryas cold interval (11.2-10.0 ka) in response to decreased evaporation and increased precipitation| The driest interval of the early-middle Holocene occurred similar to 9 ka| at the time of maximum summer solar insolation. A second highstand occurred during the Hypsithermal (similar to 8.5-5.5 ka) in response to increased precipitation at a time when the interior of North America underwent maximum aridity| This out-of-phase relationship between northeastern North America and the midcontinent during the Hypsithermal may have been a consequence of a northward shift of the jet stream and a change of precipitation patterns in response to increased global warmth. If the Hypsithermal can be used as an analog for potential global warming| the northeastern United States may experience future increases in regional precipitation. 4287,1996,5,2,Paleopedological approach to evaluation of soil response to anthropogenic global warming,Buried soils contain information which may be used to forecast soil changes related to global climate warming. Average global warming by 0.8-1 degrees C corresponds to the Holocene thermic optimum (5500-6000 years ago) and warning by 1.8-2.0 degrees C corresponds to the last Mikulino interglacial optimum (125 000 years ago). The reconstructions are regarded only as an element of the forecast. Drafts of scenarios are suggested for Eastern Europe in case of global warning| taking into account equilibrium and non-equilibrium pedogenic models. 4106,1996,3,3,Pasture burning in Amazonia: Dynamics of residual biomass and the storage and release of aboveground carbon,Aboveground biomass in cattle pasture converted from tropical dense forest was studied both before and after reburning in Brazilian Amazonia. In a 7-year-old pasture studied in Apiau| Roraima| the aboveground dry weight of biomass (live plus dead) exposed to burning consisted of 96.3 t ha(-1) of original forest remains| 6.2 t ha(-1) of secondary successional vegetation (woody invaders in the pasture)| and 8.0 t ha(-1) of pasture grass (carbon contents 48.2%| 45.4%| and 42.2%| respectively). In terms of carbon| burning efficiencies for these three categories were 13.2%| 66.7% and 94.6%| respectively. Net charcoal formation was 0.35 t C ha(-1) or 0.63% of the carbon exposed to the reburn| while the total accumulated since conversion (including the initial burn) is estimated at 2.3 t ha(-1) (1.82% of the predeforestation aboveground biomass carbon stock). The dynamics of the original forest remains were represented in simulations that included parameters such as charcoal formation| burning efficiency and carbon concentration in different biomass components. Releases from initial burning of the cleared forest (44.0 t C ha(-1)) plus releases over the course of the succeeding decade through combustion (12.5 t C ha(-1)) and decay (51.5 t C ha(-1)) total 92% of the original forest biomass carbon (126 t C ha(-1)). Of biomass carbon remaining after the initial burn (84.3 t C ha(-1))| 76.0% is released: 61.1% through decay and 14.9% through combustion in reburns| while 1.2% is net conversion to charcoal in the reburns. These results indicate an amount of charcoal accumulation that is smaller than some carbon calculations have assumed| therefore suggesting a greater impact on global warming from conversion of forest to pasture. 4244,1996,4,4,Performance bounds on acoustic thermometry of ocean climate in the presence of mesoscale sound-speed variability,The ability to measure climatic changes in ocean temperature is fundamentally limited by the presence of mesoscale variability. Because ocean acoustic propagation can be used to measure the range-averaged temperature profile| long-range acoustic transmissions have been proposed as a means of filtering out mesoscale variability in order to measure a global warming| related trend in mean temperature. In this paper| the Cramer-Rao lower bound (CRLB) on the estimation of the mean depth-dependent temperature profile given a single acoustic transmission is evaluated to provide an indication of the highest accuracy which could be achieved by this experiment. The CRLB derived here applies to broadband vertical arrays of arbitrary length and thus extends previous work. Evaluation of the bound is performed using models of sound-speed variability derived from real Pacific environmental data. Results indicate that the performance of an acoustic thermometry system is limited by mesoscale variability above a threshold value of observation-time-signal-to-noise ratio product and is acoustic noise limited below this threshold. Further| comparisons of the CRLB above this threshold suggest that for a 5000-km source-receiver separation| ATOC accuracy may vary from between 0.01 and 0.1 degrees C depending on the shape and uncertainty of the change in mean temperature profile. (C) 1996 Acoustical Society of America. 4153,1996,2,3,Permafrost distribution in the Northern Hemisphere under scenarios of climatic change,The proportion of the Earth's land area underlain by permafrost| currently about 25%| is expected to contract substantially in response to climatic warming. Maps of permafrost distribution in the northern hemisphere were generated using three general circulation models and an empirical paleoreconstruction| all scaled to a 2 degrees C global warming| in conjunction with a permafrost model that has successfully replicated the arrangement of contemporary permafrost zones in several high-latitude regions| The simulations indicate a 25-44% reduction in the total area occupied by equilibrium permafrost. Conditions specified by the climate models result in a poleward (north-northeast) displacement of all permafrost zones. The continuous permafrost zone was most severely impacted in the simulations| with reductions in its areal extent ranging from 29% to 67%| The permafrost model was also used to hindcast the distribution of permafrost in Russia during the Holocene climatic optimum and Eemian interglacial. Agreement of modeled results with mappings based on independent criteria confirm the model's effectiveness. 4216,1996,5,3,Pliocene climates: The nature of the problem,The Pliocene may have been the last time period when global temperatures were greater than present. The Pliocene data base is sufficiently complete to provide a valuable test for climate model predictions for warm time periods. This paper reviews some key issues with respect to understanding and verifying theories for the origin of Pliocene warmth. There are two main factors cited to explain Pliocene warmth-higher CO2 levels or higher levels of ocean heat transport. The two explanations may not be exclusive; for example CO2 increases may drive ocean heat transport changes. However| initial proxy-CO2 reconstructions suggest|that the CO2 perturbation is very small (similar to 100 ppm) to effect such large changes in climate| Considerably more data are needed to evaluate the magnitude of Pliocene CO2 changes. Although more modeling work is also required| it is necessary to continue evaluation of input data used to force model results (particularly sea surface temperatures). Continued simulations and evaluation of pCO(2) and SST results should enable us to better understand how the earth responds during a global warming and determine whether our models are properly simulating such changes. 4263,1996,4,4,Population growth and global CO2 emissions - A secular perspective,Considerable scientific effort has been applied to the question of whether worldwide fossil fuel combustion and the resultant emission of CO2 (as well as emissions of other greenhouse gases) will cause a discernible enhancement of the greenhouse effect in the next century| A more precise understanding of the contribution of human activity to potential global warming (vis-ri-vis natural climatic variability) is of critical policy interest| Surprisingly little research has been devoted to establishing the underlying statistical relationship between human activities and CO2 emissions| In this paper| we explore the nature of the relationship between global population growth and CO2 emissions by employing the test of causality developed by Granger on annual data for 1880-1989| as well as more comprehensive error correction and cointegration models| The results suggest a lack of a long-term equilibrium relationship| but imply a short-term dynamic relationship from CO2 to population growth. 4156,1996,3,3,Possible greenhouse effects of tetrafluoromethane and carbon dioxide emitted from aluminum production,Tetrafluoromethane (CF4) is an extremely stable gas which strongly absorbs infrared radiation at similar to 8 mu m| and therefore is capable of influencing the greenhouse effect. No natural sources have been identified| and the major anthropogenic source appears to be the electrolytic smelting of alumina to produce aluminum. Measurements of CF4 concentrations in the atmosphere are reviewed| and these are combined with aluminum production rates to provide an estimate of 1.3-3.6 kg of CF4 emitted per ton of aluminum produced for the period up to similar to 1985. Aluminum production also requires large amounts of electrical energy| leading to the emission| of as much as 22 tons of carbon dioxide per ton of aluminum due to fossil fuel combustion in power plants; The|present day contribution of hydroelectric power reduces this figure to about 14 tons of carbon dioxide per ton of aluminum. An estimate of the relative radiative trapping of CF4 and CO2 emitted in aluminum production during this same period (1900-1985) indicates that the effect of CF4 is about one-third that of the CO2 formed by. aluminum production. However| the emission of fluorocarbons from modem aluminum electrolysis cells is much lower than previous estimates indicate| and this factor is considered in estimating potential long-term global warming effects of CF4 and CO2 from aluminum production. Possible processes leading to removal of CF4 from the atmosphere are described. Copyright (C) 1996 Elsevier Science Ltd 2523,1996,2,4,Potential effects of climate change on corn production in Zimbabwe,This study uses Global Circulation Models (GCMs) and the dynamic crop growth model CERES-Maize to assess the potential effects of climate change on corn (Zea mays L.) in Zimbabwe. Corn is the most widely grown crop in Zimbabwe and is often under environmental stress due to high ambient temperature and low rainfall conditions. Global climate change scenarios suggest corn productivity in Zimbabwe will decrease dramatically under non-irrigated or irrigated conditions in some regions of agricultural production. The reductions in corn yields are primarily attributed to ambient temperature increases which shorten the crop growth period| particularly the grain-filling period. If climate effects occur farmers may find corn production an unacceptably risky activity. Adaptation options are available but financial costs may be prohibitive to communal area farmers. 2497,1996,2,3,Potential effects of global climate change on small north-temperate lakes: Physics| fish| and plankton,A 10-yr record of the thermal characteristics of four lakes at the North-Temperate Lakes Long-Term Ecological Research site was analyzed and used to validate simulations of lake physics with the dynamic reservoir simulation model. Simulations of cool| warm| and intermediate years were rerun with meteorology from four general circulation models with a doubling of CO2. In all simulations with doubled CO2 there is an earlier onset of stratification| increased summer epilimnetic temperature ( 1-7 degrees C)| and an increased intensity and longer duration of stratification. Maximum surface temperatures at times may exceed upper lethal limits of warm and cool water fish in some scenarios. Suitable thermal habitat for cold water| cool water| and warm water fish generally increases in all scenarios after climate change. Changes in the vertical migration of Daphnia| however| are expected to vary depending on the interaction of thermal stratification and fish habitat use. In northern Wisconsin lakes with cold water planktivores| habitat overlap between fish and zooplankton is expected to decrease| while in southern Wisconsin lakes habitat overlap is expected to increase. Although most physical responses of lakes to climate change are consistent among all climate scenarios| biological responses will likely be more variable owing to the complex nature of factors determining ecological interactions in lakes. 2494,1996,4,3,Potential environmental impacts of future halocarbon emissions,An integrated analysis of future halocarbon emissions and their environmental impacts shows that strict global compliance is required if the Montreal Protocol is to accomplish the goal of eliminating the lower stratospheric ozone hole. This analysis is integrated in the sense that demographic| economic| and regulatory processes controlling future production were linked explicitly to the technological factors translating production into emissions and the environmental processes transforming emissions into environmental impacts. Given current models of halocarbon transformation and atmospheric response| this research suggests that if a small percentage of nations continues to expand production at modest rates| the ozone hole will not be eliminated. In addition| high growth rate assumptions for halocarbon production by noncompliance nations will result in significantly increased ozone depletion. This research also shows that the continued use of small amounts of ozone-depleting substances for essential uses and the failure to adequately replace all ozone-depleting substances can eliminate the possibility of returning the atmosphere to pre-ozone hole conditions. The global climate change potential of halocarbons is fairly small if growth rates for chlorofluorocarbon substitutes remain low. If growth rates return to precontrol levels| these substitutes could contribute significantly to global climate change. 2484,1996,2,4,Potential impact of global climate change on forest distribution in Sri Lanka,The potential impact of climate change on forest distribution in Sri Lanka was evaluated. The Holdridge Life Zone Classification was used along with current climate and climate change scenarios derived from two general circulation models| the Geophysical Fluid Dynamics Laboratory model and the Canadian Climate Centre Model| at a 0.5 degrees x 0.5 degrees resolution. Current and future distributions of life zones were mapped with a Geographic Information System. These maps were then used to calculate the extent of the impact areas for the climate change scenarios. The current distribution pattern of forest vegetation includes tropical very dry forest (6%)| tropical dry forest (56%)| and tropical wet forest (38%). Results obtained using the Geophysical Fluid Dynamics Laboratory model show an increase in tropical dry forest (8%) and decrease in tropical wet forest (2%). The Canadian Climate Centre Model scenario predicted an increase in tropical very dry forest (5%) and tropical dry forest (7%)| and a decrease in tropical wet forest (11%). Both models predicted a northward shift of tropical wet forest into areas currently occupied by tropical dry forest The application of general circulation models such as the Geophysical Fluid Dynamics Laboratory model and the Canadian Climate Centre Model| as well as the Holdridge Life Zone Classification| to estimate the effect of climate change on Sri Lankan forests in this paper indicates that these methods are suitable as a tool for such investigations in Sri Lanka. 2470,1996,2,4,Potential impacts of climate change on citrus and potato production in the US,Potential impacts of global climate change on fruit and vegetable yield in the US were investigated through simulations of citrus and potato. Simulated treatments included combinations of three increased temperature regimes (+1.5| +2.5 and +5.0 degrees C)| and estimates of the impact of three levels of atmospheric carbon dioxide (440| 530| and 600 ppm) in addition to control runs representing current climatic conditions. Adaptive planting dates of -28| -14| +14 and +28 days were included in the potato simulations for current and increased temperature regimes. Twenty-two sites were simulated for citrus yields and 12 sites for potato| using climate records from 1951 to 1980. Response surfaces were developed for all combinations of increased temperature and CO2. Results of citrus simulations without CO2-induced yield improvement indicate that production may shift slightly northward in the southern states| but yields may decline in southern Florida and Texas due to excessive heat during the winter. CO2 effects tended to counteract the decline in simulated citrus yields. Fall potato production under current management practices appears vulnerable to an increase in temperature in the northern states; increased CO2 and changes in planting date were estimated to have minimal compensating impacts on simulated potato yields. 4234,1996,2,4,Potential impacts of climate change on ecosystems: A review of implications for policymakers and conservation biologists,Climate change represents a significant threat to global biodiversity and ecosystem integrity. The UN Framework Convention on Climate Change (UNFCCC)| which has been ratified by 118 nations and came into force in 1994| has amongst its aims the protection of ecosystems. This paper reviews the relevant text in the Convention and gives an overview of scientific efforts to provide policy-makers with the necessary information on ecosystem impacts. The sensitivity of different types of ecosystem to climatic change is discussed and the concepts of ecological limits and thresholds are addressed and examples given. The paper concludes there is a need for a better understanding of the impacts of climate change on ecosystem resilience in order to maintain biological diversity and respond to the needs of policymakers in implementing the UNFCCC. Recommendations are made for increased research effort| including increased resolution of climate models| better predictive capacity at a regional level for within- and between-year rainfall patterns| seasonality and extreme events. Collaborative monitoring programs| including long-term ecological research along climate gradients| are proposed for 4 biomes: coastal wetlands| montane ecosystems| coral reefs and Arctic ecosystems. 2526,1996,2,3,Potential impacts of future climate change on nyala Tragelaphus angasi in Lengwe National Park| Malawi,General Circulation Models (GCMs) were used to develop climate change scenarios for the Lengwe National Park in Malawi. Scenarios of future precipitation and ambient temperature were in turn used to evaluate habitat suitability of 5 ungulate populations and to rank their vulnerability to global climate change in the park. Preliminary results suggest that ambient temperatures may rise with a doubling of atmospheric CO2| and precipitation will be more variable. The vulnerability assessment results suggest that all the ungulates| especially nyala antelope Tragelaphus angasi| could be highly susceptible to climate induced changes in habitat and food supply. Adaptive measures| such as translocation| culling| and expanding the water supply| may alleviate climatic change impacts on nyala and other ungulates. 4275,1996,2,4,Predicting changes in the composition of New Zealand's indigenous forests in response to global warming: A modelling approach,A model to predict the effects of global warming on the composition of New Zealand's native forests is described. Relationships between the current distribution of 41 tree species and site temperature| solar radiation| water balance| lithology| and drainage for 14 500 plots have been analysed using non-parametric regression. Distributions of species were then predicted for points on a 5 km grid across New Zealand. A test for residual spatial autocorrelation using a 'proximity' variable| indicated that New Zealand's four Nothofagus species have distributions less well correlated with environmental variables than most other species. inclusion of the 'proximity' variable in the regressions also substantially improved predictions of Nothofagus distribution. Predictions for other species were improved by incorporating a term representing interaction with the patchily distributed but strongly dominant Nothofagus species. Preliminary results from a cluster analysis of the combined predictions for all species indicate that the model successfully reconstructs the existing pattern of New Zealand's indigenous forests. Estimation of the effects of global warming on species distribution was done by introducing a perturbation to represent an overall increase in temperature of 2 degrees C. The results indicate that a substantial disequilibrium is likely to occur between the current forest pattern and expected warmer temperatures. Copyright (C) 1996 Elsevier Science Ltd 4256,1996,2,3,Prediction of possible changes in glacio-hydrological characteristics under global warming: Southeastern Alaska| USA,We use the Wetherald and Manabe climate model to predict the: response of mountain glaciers to a doubling of atmospheric carbon dioxide. The| response is measured in terms of a change in the equilibrium-line altitude (ELA) and I the glacier terminus altitude (GTA)| net accumulation-ablation on these altitudes and the melt runoff for 12 mountain-glacier regions in southeastern Alaska| U.S.A. The; methods we use involve extrapolating climate-model temperature fields to a glacier's I location| and empirical-statistical relationships between air temperature and percentage of solid precipitation| and between summer air temperature and ablation and melt runoff. Our study shows that| under global warming| glaciation in southeastern Alaska will not disappear| but mass exchange of glaciers will be more intensive and the ELA value will increase by 300-760 m| depending on the glacier's: distance from the ocean. 4229,1996,2,4,Pressures| trends| and impacts in coastal zones: Interactions between socioeconomic and natural systems,This paper assesses the status of coastal zones in the context of expected climate change and its related impacts| as well as current and future socioeconomic pressures and impacts. It is argued that external stresses and shocks relating to sea-level rise and other changes will tend to exacerbate existing environmental pressures and damage in coastal zones. Coastal zones are under increasing stress because of an interrelated set of planning failures including information| economic market| and policy intervention failures. Moves towards integrated coastal zone management are urgently required to guide the coevolution of natural and human systems. Overtly technocentric claims that assessments of vulnerability undertaken to date are overestimates of likely future damages from global warming are premature. While it is the case that forecasts of sea-level rise have been scaled down| much uncertainty remains over| for example| combined storm| sea surge| and other events. In any case| within the socioeconomic analyses of the problem| resource valuations have been at best only partial and have failed to incorporate sensitivity analysis in terms of the discount rates utilized. This would indicate an underestimation of potential damage costs. Overall| a precautionary approach is justified based on the need to act ahead of adequate information acquisition| economically efficient resource pricing and proactive coastal planning. 2517,1996,2,4,Processes of wetland loss in India,Wetlands in India supply crucial human and animal needs such as drinking water| protein production| fodder| water purification| wildlife habitat| and flood storage. Increased appreciation of uses and threats is essential to protect wetlands where justified. Three quarters of India's population is rural| it places great demands on India's wetlands and losses continue to occur. This paper is based on extensive discussions with natural resource managers| government employees| farmers| academicians| and resource users at dozens of sites in India| as well as an extensive literature search. Twelve important kinds of wetland loss are identified and mechanisms believed to be causing them discussed: (1) agricultural conversion| (2) direct deforestation| (3) hydrologic alteration| (4) inundation| (5) defoliation| (6) altered upper watersheds| (7) accumulative water demands| (8) water quality degradation| (9) wetland consolidation| (10) global climate change| (11) ground-water depletion| (12) exotic species and biodiversity. Wetland understanding| management| and public awareness in India must continue growing if wetland resources are to remain functional. 4201,1996,3,2,R&D for technology to solve global warming,Global warming is a problem in which the combustion of coal| oil? and other fossil fuels causes the atmospheric concentrations of greenhouse gases| such as carbon dioxide (CO2)| to increase. This results in mounting global air temperatures that lead to climatic change. Specifically| global warming will cause a rise in sea levels| changes in the rain-fall patterns| and other problems. In order to secure the route to solutions for global warming that requires new responses in ways that are compatible with economic growth| it is essential to achieve breakthroughs with innovative technologies. In addition to energy-related R&D| also important are R&D for CO2 absorption and fixation for a fundamental solution to global warming. Japan has started the development of innovative environmental technologies| such as technologies for CO2 fixation and utilization. 4250,1996,3,3,Recent climatic change| greenhouse gas emissions and future climate: The implications for India,In this paper| we discuss past climatic trends over India| greenhouse gas emissions due to energy consumption| forest and land-use changes| climate change scenarios for the year 2050| potential consequences for agriculture and cyclone activity and the possibility that India might limit the increasing trend in its emissions. India's mean surface air temperature has increased significantly by about 0.4 degrees C over the past century. Neither monsoon nor annual rainfall shows any significant trend. On average| there has been a rise in sea levels around India over recent decades| though considerable uncertainties exist in the accuracy and interpretation of the available data. Carbon emissions from the energy sector amount to 71 MT a year| equivalent to all other sectors combined. From land-use data| a marginal net sequestration of 5.25 million tonnes of carbon occurred during 1986. Following the IPCC guidelines| methane emissions from rice and livestock are estimated at 17.4 and 12.8 Tg/year| respectively. According to recent climate model projections| India may experience a further rise in temperature of 1 degrees C by the year 2050| about four times the rate of warming experienced over the past 100 years. A modest increase in precipitation amounts might occur. Cereals production is estimated to decrease and the nutrition security of the population-rich but land-hungry region of India might be hampered. An increase in local tropical cyclone activity may occur over the next century| posing added problems as large areas in the coastal regions have a dense population. About 70% of the electricity generation in India is from coal-based power stations. Altering this dependence significantly to reduce emissions would imply a substantial change in the present energy policy of India. There is great potential for improving energy efficiency and conservation. The adoption of cleaner coal-technologies should be considered| as must the development of renewable| non-conventional energy sources. In all cases| serious institulional barriers and resource limitations need to be addressed. The scope for carbon sequestration is limiled by land availabilily and other factors. It is argued that any response to global warming must be located firmly in the framework of sustainable development. 4192,1996,2,3,Redistribution of sea level rise associated with enhanced greenhouse warming: A simple model study,Future sea level rise from thermal expansion of the World Ocean due to global warming has been explored in several recent studies using coupled ocean-atmosphere models. These coupled models show that the heat input by the model atmosphere to the ocean in such an event could be quite non-uniform in different areas of the ocean. One of the most significant effects predicted by some of the models is a weakening of the thermohaline circulation| which normally transports heat poleward. Since the greatest heat input from enhanced greenhouse warming is in the higher latitudes| a weakening of the poleward heat transport effectively redistributes the heat anomaly and the associated sea level rise to lower latitudes. In this study| the mechanism of ocean circulation spindown and heat redistribution was studied in the context of a much simpler| linearized shallow water model. Although the model is much simpler than the three-dimensional ocean circulation models used in the coupled model experiments| and neglects several important physical effects| it has a nearly 10-fold increase in horizontal resolution and clearer dynamical interpretations. The results indicated that advanced signals of sea level rise propagated rapidly through the action of Kelvin and Rossby waves| but the full adjustment toward a more uniform sea level rise took place much more slowly. Long time scales were required to redistribute mass through narrow currents trapped along coasts and the equatorial wave guide. For realistic greenhouse warming| the model showed why the sea level rise due to ocean heating could be far from uniform over the globe and hence difficult to estimate from coastal tide gauge stations. 2474,1996,2,4,Reef coral diversity and global change,Regional anthropogenic processes such as pollution| dredging| and overfishing on coral reefs currently threaten the biodiversity of stony corals and other reef-associated organisms. Global climate change may interact with anthropogenic processes to create additional impacts on coral diversity in the near future. In order to predict these changes| it is necessary to understand the magnitude and causes of variation in scleractinian coral diversity throughout their 240 million year history. The fossil record documents long periods of speciation in corals| interrupted repeatedly by events of mass extinction. Some of these events relate clearly to changes in global climate. Diversity in reef corals has increased since their last period of extinction at the end of the Cretaceous (65 My BP)| and is still rising. During the last 8 million years| the fragmentation of the once pantropical Tethys Sea separated corals into two major biogeographical provinces. Periods of glaciation also have caused major changes in sea level and temperature. Accumulated evidence supports the theory that relative habitat area and changing patterns of oceanic circulation are mainly responsible for the two observed centres of recent coral diversity at the western tropical margins of the Atlantic and Pacific oceans. At predicted rates of climate change in the near future| coral reefs are likely to survive as an ecosystem. Increases in sea level may actually benefit corals and lead to regional increases in diversity if new habitat area on back reefs is opened to increased water circulation and thus coral dispersal. Rising temperature may cause higher rates of coral mortality and even local extinction in isolated| small populations such as those on oceanic islands. The effects of increases in ultraviolet radiation (UV) are largely unknown| but likely to be negative. UV may damage planktonic coral propagules in oceanic surface waters and thus decrease rates of gene flow between coral populations. This may result in increased local extinctions| again with the strongest impact on widely separated reefs with small coral populations. The largest threats to coral diversity are regional anthropogenic impacts| which may interact with global climate change to exacerbate rates of local species extinctions. Centres of high reef coral diversity coincide with human population centres in south-east Asia and the Caribbean| and thus the greatest potential for species loss lies in these geographical areas. 4207,1996,4,4,Relationship between acoustic bandwidth and characteristics of sound propagation in west Mediterranean Sea,Recently| ocean acoustic tomography (OAT) has been used to investigate the phenomenon of global warming and in wide-area oceanic observations. OAT can determine the sound-speed profile from measured acoustic travel times over known ray paths. The seawater temperature profile and the existence of ocean currents can be estimated using the sound-speed profile. However| the measured arrival time structure contains many pulses with different paths. Ray geometry fundamentals (i.e.| numbers of turning points of rays| initial angle| etc.) must be properly identified. The sound-speed structure varies with observation area (i.e.| west Mediterranean Sea| low-| mid-latitude sea area| etc.) and season. It has been shown by the Japan Marine Science and Technology Center (JAMSTEC) that a special ocean structure with sound speed increasing linearly with depth is formed in the west Mediterranean Sea. We have to understand the characteristics of sound propagation for each sea area in advance. In this paper| the characteristics of sound propagation for an ocean model for areas such as the west Mediterranean Sea have been analyzed in the time domain using Stickler's normal mode method (SNM). The effects of acoustic bandwidth (ABW) on the pattern of arrivals have been examined. 4110,1996,4,3,Relative radiative forcing consequences of global emissions of hydrocarbons| carbon monoxide and NOx from human activities estimated with a zonally-averaged two-dimensional model,A global two-dimensional (altitude-latitude) chemistry transport model is used to follow the changes in the tropospheric distribution of the two major radiatively active trace gases| methane and ozone| following step changes to the sustained emissions of the short-lived trace gases methane| carbon monoxide and non-methane hydrocarbons. The radiative impacts were dependent on the latitude chosen for the applied change in emissions. Step change global warming potentials (GWPs) were derived for a range of short-lived trace gases to describe their time-integrated radiative forcing impacts for unit emissions relative to that of carbon dioxide. The GWPs show that the tropospheric chemistry of the hydrocarbons can produce significant indirect radiative impacts through changing the tropospheric distributions of hydroxyl radicals| methane and ozone. For aircraft| the indirect radiative forcing impact of the NOx emissions appears to be greater than that from their carbon dioxide emissions. Quantitative results from this two-dimensional model study must| however| be viewed against the known inadequacies of zonally-averaged models and their poor representation of many important tropospheric processes. 4228,1996,2,4,Response of stream invertebrates to a global-warming thermal regime: An ecosystem-level manipulation,We manipulated| in accord with global-warming predictions| the thermal regime of a permanent first-order stream near Toronto| Ontario| Canada. We examined the effects of a 2-3.5 degrees C water-temperature increase on densities| biomass| species composition| and life histories of resident stream invertebrates. The stream was divided longitudinally at the source into two channels| one control and one experimental| and a before and after (BACI) design was employed such that one pre-manipulation year was followed by 2 yr of the temperature manipulation. Changes in the experimental channel following commencement of the manipulation included: (1) decreased total animal densities| particularly Chironomidae (Diptera); (2) earlier onset of adult insect emergence; (3) increased growth rates and precocious breeding in Hyalella azteca (Amphipoda); (4) smaller size at maturity for Nemoura trispinosa (Plecoptera) and H. azteca; and (5) altered sex ratios for Lepidostoma vernale (Trichoptera). These results partially corroborate previous laboratory and field studies. However| variation in the responses of individual target species to the manipulation was unexpected and may have been influenced by the genetic structure of local populations. We conclude that levels of gene flow among habitats may be critical to the degree of impact seen as a result of large-scale thermal perturbation (e.g.| global warming). 2482,1996,2,3,Responses of some North American CAM plants to freezing temperatures and doubled CO2 concentrations: Implications of global climate change for extending cultivation,Environmental influences on the cultivation of Crassulacean acid metabolism (CAM) plants| which are especially well adapted to arid regions with limited rainfall| were evaluated with respect to two aspects of global climate change. Cellular uptake of a vital stain| which occurs in living cells only| was halved at -6+/-1 degrees C for the cultivated CAM species Agave salmiana| Opuntia ficus indica and Stenocereus queretaroensis growing at day/night air temperatures of 30 degrees C/20 degrees C compared with -12 degrees C for the wild species Opuntia humifusa. When plants were grown at reduced temperatures of 10 degrees C/0 degrees C| stain uptake was halved at about -8 degrees C for the cultivated species but at -24 degrees C for O. humifusa. The greater low-temperature sensitivity and the lesser low-temperature acclimation of the cultivated species severely limit the regions where they can presently be grown| but such regions will expand as air temperatures rise accompanying global climate change. When the atmospheric CO2 concentration was doubled from the current ambient value of 360 mu mol mol(-1) to 7201 mu mol mol(-1)| net CO2 uptake over 24-h periods increased 36% for A. salmiana and S. queretaroensis; about one-third of the increase resulted from higher net CO2 uptake rates in the last 4 h of daytime and two-thirds from higher rates during the first 8 h of the night. The doubled atmospheric CO| concentration predicted to occur before the end of the twenty-first century will increase CO2 uptake and hence biomass productivity of such CAM species| further expanding the regions where they may be profitably cultivated. (C) 1996 Academic Press Limited. 2516,1996,2,4,Scientific community recognizes link between ecology and health,Healthy climate for study: The scientific community| including many prestigious organizations| is beginning to recognize the connection between global climate change and the emergence and reemergence of infectious diseases; but despite the heightened interest in exploring the link| funding for such efforts is hard to come by| a frequent victim of budget cutbacks. 4131,1996,2,4,Sea level rise and impacts on nearshore sedimentation: An overview,Impacts on nearshore sedimentation arising Introduction from potential sea level change of the magnitude predicted in Intergovernmental Panel on Climatic Change scenarios associated with global warming are reviewed. For sandy duned coasts| the obvious sedimentation impacts include potential erosion of coastal dunes with implied deposition of the eroded material in the nearshore| possible deepening of embayments| and flooding of wetlands. For the sandy coasts a number of two-dimensional models are available for predicting shore line change| but there are significant difficulties in applying Bruun-type models for dune erosion and assessment of sediment redistribution over the inner shelf| and for predicting the amount of shoreline retreat for a given rate of sea level rise. If the beach profile contains excessive sand relative to its equilibrium profile| sensu Dean (1991)| then shoreline retreat may not occur upon sea level rise. From the evidence of Kiel Bay| at least in these semi-enclosed basin types| it is during major transgressions that maximum deposition in adjacent basins occurs| due to the sea eroding weakly consolidated and weathered surface regolith. But at the same time climatic patterns were re-adjusting and probably contributed to maximum deposition in adjacent shelf and basins below wave base. 4262,1996,5,3,Sea-level changes in the tectonically stable Malay-Thai Peninsula,The Malay-Thai Peninsula is part of Sundaland| a geological region of relative crustal stability. Therefore| the positions of old shorelines (of the past 20|000 years or so) can be considered to indicate positions of actual past sea levels. Over 200 shoreline indicators at positions below as well as above present sea level have been radiocarbon dated. These dated positions indicate that prior to 6 ka the sea rose from at least 90 m below present sea level at rates that initially amounted to 15 mm/year and later became 6 mm/year. At ca. 6 ka| the rising sea surpassed its current position and at ca. 5 ka| it reached 5 m. During this maximum marine inundation| the peninsula was narrower| since the low coastal plains did not yet exist. In the period following this maximum transgression| the available shoreline data indicate that regional sea level subsided through a series of fluctuations that were characterized by amplitudes of 2 m and periods of about 2000 years. The peaks and troughs of the fluctuations became progressively lower. The latest peak was at about +1.7 m (or 0.7 m above present high tide) a few hundred years ago| The cause of these fluctuations is not yet known| but the trend suggests that| in the near future| regional sea level may subside at annual rates between 1.5 mm and 2 mm| This rate of descent is 25 to 30% of the estimated rate of sea-level rise that may result from global warming. In other words| for the Malay-Thai Peninsula| the effect of sea-level rise on account of manmade greenhouse gases will be partly compensated by actual subsidence of regional sea level. 4251,1996,2,4,Seasonal relationship between temperature| precipitation and snow cover in a mountainous region,An analysis of correlation coefficients for climatological data covering the period 1901-1994 or 1931-1994 for six locations in Switzerland has been made in order to highlight the relationships between temperature| precipitation (rain and snow) and snow in summer and in winter. The results show that colder summers tend to be associated with more precipitation| mainly in terms of the frequency of occurrence of precipitation| but also in terms of its abundancy. In winter| sites located at lower altitudes behave differently from those at higher elevations. At lower altitudes| warmer winters tend to be rainier and to have less snow (only a small part of winter precipitation falls in the form of snow). Above 1000-1500 m| correlations between temperature on the one hand| and precipitation or snow on the other| tend to be weaker than at lower elevations; warmer winters are associated with less snow but also with less precipitation in general| while the relationship between precipitation and snow is stronger. These results confirm that during cold periods of the past| such as Lobben Phase (1400 BC-1230 BC) cold summers were probably linked to frequent and abundant precipitation. These conditions led to increased mortality as well as to population migrations. In terms of potential future global warming if the current temperature/precipitation relationships remain unchanged| then warmer summers will likely be linked to a decrease in precipitation. Higher winter temperatures can be expected to lead to a general decrease of snow and to a decrease in precipitation| but only at higher elevations; warmer winters would conversely be associated with an increase in precipitation at lower altitudes. 2476,1996,2,4,Sensitivities of groundwater-streamflow interaction to global climate change,The sensitivities of groundwater-streamflow interaction to global climate change over the medium-sized mountainous Mesochora catchment in central Greece have been analysed. The global climate change was simulated through a set of hypothetical and monthly GISS (Goddard Institute for Space Studies) scenarios of temperature increases coupled with precipitation changes. The catchment hydrological regime| which is dominated by spring snowmelt runoff| was simulated by the coupling of the snowmelt and soil moisture accounting models of the US National Weather Service River Forecast System (US NWSRFS). The groundwater was represented through a lower zone one-tension water storage and two free water storages parameterized by the soil moisture model| while the streamflow was the sum of direct runoff| surface runoff and interflow from the upper zone free water| plus the primary and secondary baseflows yielded by the model. The interaction between groundwater and streamflow was expressed by the ratio of the two variables on a seasonal and monthly basis. Both representations of global climate change resulted in a moderate influence on the groundwater-streamflow interaction during the winter months and in a very high one in the spring and summer months. In particular| the major seasonal shift in the snow accumulation pattern related to climate change| as well as the large runoff reduction and evapotranspiration increase occurring in spring and summer months| boosted considerably the groundwater to streamflow ratio. This latter would probably have negative impacts on various problems of water resources management (e.g. droughts| water supply| irrigation| water pollution). 4129,1996,2,4,Shoreline stabilization approaches in response to sea level rise: US experience and implications for Pacific island and Asian nations,Coastal erosion is a worldwide problem; it is estimated that over 70% of the world's beaches are currently experiencing erosion(Bird| 1985)| and this number may approach 90% in the United States.(1) Almost every conceivable form of shore protection has been attempted in the United States| including construction of seawalls| groins| and jetties as well as beach nourishment. The principal approach to protecting coastal property and maintaining recreational beaches in the United States today is beach nourishment. Engineering structures such as groins and seawalls have often been shown to have detrimental effects on adjacent beaches. Also| their construction and maintenance costs are quite high. Therefore|coastal communities have come to rely on a ''soft'' engineering solution - beach nourishment because it is environmentally sound| aesthetically pleasing| and so far| economically feasible. However| global warming and accelerated sea level rise will cause more rapid rates of beach loss and could make even this alternative too costly for many resort areas along the U.S. shoreline. The cost to nourish all the major recreational oceanic beaches inthe United States was estimated based on various sea level rise scenarios. The beach nourishment approach involves placing enough sand on the beach to maintain stable (nonretreating) conditions in response to rising sea level. The quantity of sand required to ''hold the line'' is evaluated under various sea level rise scenarios fi-om the baseline scenario to the I-m estimate of the Intergovernmental Panel on Climate Change. Beach nourishment is not a practical alternative for most Pacific island nations because sand is a scarce resource. In fad| beaches are often mined for sand for construction| contributing to beach erosion For mainland countries| beach fill projects are more practical Singapore was one of the first countries to use this technology in combination with building offshore breakwaters to form artificial headlands. As Western style sunbathing and the overall popularity of beaches for recreation continue to grow| beach nourishment can be expected to become a more common way to deal with sea level rise induced coastal erosion for highly developed beach resort areas. 4239,1996,3,4,Short communication: Hydrogen| the inherently recyclable fuel,Hydrogen| now well-known as an intermediate fuel which neither pollutes nor contributes to global warming| is shown to be essentially inexhaustible. The reason is that electrolytic production and combustion are governed by the same chemical reaction in opposite directions. The hydrogen recycles via the atmosphere and oceans indefinitely. 4208,1996,4,4,Siberian CO2 efflux in winter as a CO2 source and cause of seasonality in atmospheric CO2,Over three years| we found a consistent CO2 efflux from forest tundra of the Russian North throughout the year| including a large (89 g C m(-2) yr(-1)) efflux during winter. Our results provide one explanation for the observations that the highest atmospheric CO2 concentration and greatest seasonal amplitude occur at high latitudes rather than over the mid-latitudes| where fossil fuel sources are large| and where high summer productivity offset by winter respiration should give large seasonal oscillations in atmospheric CO2. Winter respiration probably contributed substantially to the boreal winter CO2 efflux. Respiration is an exothermic process that produces enough heat to warm soils and promote further decomposition. We suggest that| as a result of this positive feedback| small changes in surface heat flux| associated with human activities in the North or with regional or global warming| could release large quantities of organic carbon that are presently stored in permafrost. 4119,1996,2,3,Simulating the impact of global warming on milk and forage production in Scotland .1. The effects on dry-matter yield of grass and grass white clover swards,The purpose of the study was to assess the effect that global war ming and changes in atmospheric CO2 concentration would have on grassland production within Scotland. This required the development of a mathematical model of herbage production that was responsive to climatic factors and changes in CO2 levels. A model of pure grass and grass-white clover swards is described| and this has been used to assess the effects that the predicted increases in temperature| rainfall and CO2 might have on grass and white clover production. It is projected that global warming will increase the length of the growing season by between 12 and 37 days for every 1 degrees C rise in annual mean daily temperature. The indications are that global warming will have little effect on annual production of grass| either from pure grass or grass-white clover swards. On the other hand| white clover as a percentage of total herbage production is estimated to increase from 32% to 46% for a 2 degrees C temperature rise. Nevertheless| increasing concentrations of CO2 is predicted to increase the yields of grass and white clover under both current climatic conditions and the global warming scenario. Copyright (C) 1996 Published by Elsevier Science Ltd 4120,1996,2,4,Simulating the impact of global warming on milk and forage production in Scotland .2. The effects on milk yields and grazing management of dairy herds,The potential impact of global warming and the enhanced atmospheric CO2 concentration on grassland management on dairy farms within the UK requires assessment. This has led to the development of a mathematical model of the grazing dairy cow. The model| that embraces grass and grass-white clover swards| has been used to assess the effects that the projected increases in temperature and rainfall under global warming and the increased levels of CO2 might have on milk production and on silage conservation for a typical dairy farm. The results suggest that the impact on milk production for grass-based systems will vary depending on the locality. On the other hand| for herds grazed on grass-white clover swards milk output might increase regardless of site| when the concentration of CO2 is enhanced. As regards silage production from grass-white clover swards| under global warming and at current levels of CO2 there is an apparent tendency to increase the percentage of total silage yield obtained from the first cut| although this does nor occur for grass swards. At the same time| there are also indications that global warming will increase the percentage of clover in the herbage cut for conservation. Copyright (C) 1996 Published by Elsevier Science Ltd 4121,1996,2,4,Simulation of climate change with infrared heaters reduces the productivity of Lolium perenne L in summer,Field-grown perennial ryegrass was subjected to climate warming and elevated CO2 concentration during summer in free air conditions (no enclosure of the vegetation). Increased foliage temperature (2.5 degrees C above fluctuating ambient) was induced by heating the stand with infrared radiation sources| modulated by an electronic control device (FATI| Free Air Temperature Increase). Enhanced CO2 was produced by a FACE system (Free Air CO2 Enrichment). Exposure to simulated climate warming drastically reduced above-ground harvestable dry matter (52% loss). The nitrogen allocated to the leaf fraction was thus concentrated into less dry matter| which enhanced the nitrogen concentration on a mass basis (+17%) but also per unit leaf area (+47%). As a consequence| CO| assimilation rates were not affected in these slower growing plants in the +2.5 degrees C treatment| and the photochemical efficiency of non-cyclic electron transport of photosystem II was also unaffected. Although the plants were grown in the field without root restrictions| long-term exposure to elevated CO| concentration induced noticeable acclimation of the photosynthetic apparatus (40% loss of fixation potential)| which largely outweighed the direct stimulation in this summer period. Part of the reduced rates could be attributed to lower N concentration on a leaf area basis. The results are compared with responses of this species in sunlit conditioned greenhouses| which indicates that experiments in enclosures may underestimate effects in the field. This also emphasizes the need to validate other plant responses to climate warming and CO2 enrichment in free air conditions. 2536,1996,4,4,Soil science in transition: Soil awareness and soil care research strategies,The perceived decline of soil science in the industrialized countries needs to be remedied by greater attention (i) to fundamental aspects of soil processes and soil development in the context of global climate change and (ii) to local and regional environmental problems| Soil care is proposed as a unifying concept and challenge for geoecological sustainability| It is defined as the activity of selecting and implementing| locally and regionally| a system of soil and land use management suitable for maintaining and improving soil usefulness and quality for any selected purpose| In developing countries where| in addition| improvement of soil productivity will remain the major goal| more locally trained soil scientists will be needed to increase their relative proportion among the current number of some 50|000 soil scientists worldwide and to narrow the gap in research efforts. 2478,1996,2,4,Soil surface CO2 flux as an index of soil respiration in situ: A comparison of two chamber methods,Predictions of global climate change have recently focused attention on soils as major sources and sinks for atmospheric CO2| and various methodologies exist for measuring soil surface CO2 flux. A static (passive CO2 absorption in an alkali trap over 24 h) and a dynamic (portable infra-red CO2 gas analyzer over 1-2 min) chamber method were compared. Both methods were used for 100 different site x treatment x time combinations in temperate arable| forest and pasture ecosystems. Soil surface CO2 flux estimates covered a wide range from 0 to ca. 300 mg CO2-C m(-2) h(-1) by the static method and from 0 to ca. 2500 mg CO2-C m(-2) h(-1) by the dynamic method. The relationship between results from the two methods was highly non-linear| and was best explained by an exponential equation. When compared to the dynamic method| the static method gave on average 12% higher flux rates below 100 mg CO2-C m(-2) h| but much lower flux rates above 100 mg CO2-C m(-2) h(-1). Spatial variability was large for both methods| necessitating a large number of replicates for reliable field data| with typical coefficients of variation being in the range 10-60%| usually higher with the dynamic than the static method. Diurnal variability in soil surface CO2 flux was partly correlated with soil temperature| whereas day-to-day variability was more unpredictable. However| use of a mechanistic simulation model of CO2 transport in soil| SOILCO2| showed that very large day-to-day changes in soil surface CO2 flux can result from rainfall events causing relatively small changes in soil water content above field capacity (ca. -10 kPa)| even if CO2 production rates remained relatively unaffected. Copyright (C) 1996 Elsevier Science Ltd 2479,1996,4,4,Soils in an environmental context: An American perspective,The understanding of fundamental properties of and processes in soils has both agricultural and environmental benefits. Fundamental understanding of soil biology| chemistry| pedology| and physics can be applied to problems of production| environment| and environmental problems caused by production. Although most frequently thought of as agricultural scientists| soil scientists have many roles in modern science including environmental science. The demand for food| animal feed| and fiber continues to increase| driven by growing populations| rising aspirations and improving standards of living. On a global basis| soil science will continue to be;viewed as primarily an applied agricultural science. In contrast to the third world| concerns about agricultural production in the developed countries have diminished in this century because of the success of soil and crop science to increase production per unit area. At the same time| concerns about soil| water and air pollution have increased. Soil science knowledge is being employed to understand environmental problems such as non-point water pollution by sediment| air quality diminution by fugitive dust| and trace element transport in runoff. Studies of microbial degradation of farm chemicals has now expanded to biodegradation of organic chemicals with urban sources. Soil science plays a key role in understanding and modeling the transport of pollutants to ground water and to remediation of polluted urban environments. Soils| as occupants of most landscapes| also play important roles in buffering changes in natural ecosystems. Acid rain and global climate change are two environmental problems to which soil scientists have applied themselves. Soil scientists can be proud of their contributions to improving agricultural production and have the opportunity to continue to apply their basic understanding of soils to many environmental problems. 4170,1996,3,3,Solar-hydrogen electricity generation and global CO2 emission reduction,The relative costs and CO| emission reduction benefits of advanced centralized fossil fuel electricity generation| hybrid photovoltaic-fossil fuel electricity generation| and total solar electricity generation with hydrogen storage are compared. Component costs appropriate to the year 2000-2010 time frame are assumed throughout. For low insolation conditions (160 W m mean annual solar radiation)| photovoltaic electricity could cost 5-13 cents kWh(-1) by year 2000-2010| while for high insolation conditions (260 W m(-2)) the cost could be 4-9 cents kWh(-2) Advanced fossil fuel-based power generation should achieve efficiencies of 50% using coal and 55% using natural gas. Carbon dioxide emissions would be reduced by a factor of two to three compared to conventional coal-based electricity production in industralized countries. Ln a solar-fossil fuel hybrid| some electricity would be supplied from solar energy whenever the sun is shining and remaining demand satisfied by fossil fuels. This increases total capital costs but saves on fuel costs. For low insolation conditions| the cost of electricity increases by 0-2 cents kWh(-1)| while the cost of electricity decreases in many cases for high insolation conditions. Solar energy would provide 20% or 30% of electricity demand for the low and high insolation cases| respectively. In the solar-hydrogen energy system| some photovoltaic arrays would provide current electricity demand while others would be used to produce hydrogen electrolytically for storage and later use in fuel cells to generate electricity. Electricity costs from the solar-hydrogen system are 0.2-5.4 cents kWh(-1) greater than from a natural gas power plant| and 1.0-4.5 cents kWh(-1) greater than from coal plant for the cost and performance assumptions;adopted here. The carbon tax required to make the solar-hydrogen system competitive with fossil fuels ranges from $70-660 tonne(-1)| depending on the cost and performance of system components and the future price of fossil fuels. Leakage of hydrogen from storage into the atmosphere| and the eventual transport of a portion of the leaked hydrogen to the stratosphere| would result in the formation of stratospheric water vapor. This could perturb stratospheric ozone amounts and contribute to global warming. Order-of-magnitude calculations indicate that| for a leakage rate of 0.5% y(-1) of total hydrogen production - which might be characteristic of underground hydrogen storage - the global warming effect of solar-hydrogen electricity generation is on the order of 1% the impact of the hybrid system. Impacts on stratospheric ozone are likely to be minuscule. Copyright (C) 1996 International Association for Hydrogen Energy 2508,1996,4,4,Some new laboratory approaches to studying tropospheric heterogeneous reactions,Assessing the potential for global climate change requires a detailed understanding of the fundamental chemical and physical processes controlling the concentrations of key gases as well as particles in the atmosphere. Laboratory studies are used to obtain the basic kinetic and mechanistic data needed for inputs to models as well as for interpreting field observations. While gas-phase reactions are reasonably well-understood| ''heterogeneous'' processes involving gases and solids are not. We briefly describe applications of three approaches to laboratory studies of heterogeneous atmospheric reactions which have not been widely used for this purpose in the past: diffuse reflectance infrared Fourier transform spectrometry (DRIFTS)| transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDS)| and X-ray photoelectron spectroscopy (XPS). The application of these techniques to studying the reactions of the oxides of nitrogen with NaCl and NaBr found in sea-salt particles is described and used to illustrate their utility in obtaining both kinetic and mechanistic data. The reaction of NO2 with NaBr is found to be approximately second order in NO3| suggesting that the dimer N2O4 may be the reacting species. If this is the case| a preliminary value for the reaction probability for the N2O4-NaBr reaction at 298 K is 2 x 10(-4) with an uncertainty of a factor of three. That for the HNO3-NaCl reaction was found using XPS to be (4 +/- 2) x 10(-4). The kinetic data from these studies indicate that the NO2| reaction is too slow to be competitive with the N2O5 and HNO3 reactions. Mechanistically| both the DRIFTS and TEM-EDS studies show that water vapor even at relative humidities well below the deliquescence point causes a selective recrystallization of surface nitrate into microcrystallites of NaNO3| regenerating a fresh salt surface. This may explain held observations of some marine particles which are essentially totally devoid of chloride ions. 2535,1996,4,4,Spatial scale-dependent policy planning for land management in southern Europe,This study outlines an original tool for rural policy planning in southern Europe. This new tool is a process-based| scale-dependent| rural policy-making approach| which is designed to address increasing land degradation problems in southern Europe. Seven important processes are identified (land abandonment| devegetation| intensification in agriculture| global climate change| accelerated soil erosion| increasing water demands| urbanisation) and plotted on a space-time diagram| which clearly shows the spatial and temporal scales for which these processes are significant for landscape change in southern Europe. Conclusions are derived concerning| in particular| sustainable (optimal) rural policy-making for southern Europe's problematic land management. An optimal spatial-temporal scale for land management in southern Europe may range spatially from the ''farm'' (0.5 km(2)) to ''sub-provincial'' level (450 km(2)) and temporally from 7 to 30 years. The study delineates methods and results derivable from such a new policy-planning approach and suggests the usefulness of combining this approach with ecological land classification at the landscape level. 4283,1996,2,2,Statistical inquiry into the causes of global temperature changes,Observed changes in average global temperatures over time have led to two general avenues of discussion in the environmental literature. The scientific community has concentrated on the statistical detection of global warming and the determination of biological and industrial factors causing average world temperatures to rise. A second avenue of thought considers the issue of economic abatement by attempting to measure the pecuniary costs of global warming and the elimination of factors influencing this problem. This paper concentrates not on developing an economic model of global warming and environmental damage| but rather on examining the problem from a purely statistical vantage point. Utilizing annual data from 1950 to 1991 and optimally determined vector autoregression specifications| it is shown that general industrial growth and greenhouse gas emission levels statistically cause a persistent increase in average global temperatures. In addition| this analysis shows that increasing average world temperatures have a statistically significant negative causal impact on agricultural productivity. Given that global warming is a long-term process culminating from decades of industrial activity| statistically significant causal results derived in this paper using shortterm data are interesting. Statistical results suggest that trends in average temperatures respond to short-run fluctuations in industrial activity and population growth.
4103,1996,2,4,Statistical modelling reveals demography and time are the main contributing factors in global sperm count changes between 1938 and 1996,Declining sperm count reports have caused enormous concern to both the scientific community and to society. We reproduced the linear regression analysis and the quadratic model analysis using the 50 year sperm count data published in Carlsen's report and found that neither model adequately described the data. The reported decline in sperm count could be due to observational bias and overinterpretation of linear regression. In fact only 36% of the total variability in sperm count was explained by the linear model and 42% by the quadratic model. The linear model was no longer valid when three new European reports on sperm counts were included in the analysis. The quadratic model| however| suggested an upward trend of sperm count after 1975 (R(2) = 0.48| P <0.0001). Factors other than the 'passage of time' may have contributed to the initial decline of sperm count. An immediate candidate was demography. Our analysis showed that sperm counts in USA were significantly higher in 1938-1956 compared with those in 1957-1974 and 1975-1988| but not in the European or Asian/African/South American countries. The variability of the USA sperm count (1938-1988) explained by the linear and quadratic models was found to be 71 and 70% respectively. The quadratic model importantly indicated that the sperm count in USA decreases asymptotically towards a limiting value and global sperm counts could be increasing since 1970. The non-uniform nature of the global sperm count change suggested that local variations in pollution| diet but not global warming were important determinants of reproductive health. 2505,1996,3,3,Strategic planning and adoption of greenhouse gas mitigation options in Asia,Asia's global warming potential (GWP) is large and growing. Asia releases an estimated 8.4 billion metric tons of Carbon Dioxide (CO2) each year from fossil fuel use| cement manufactures and ''land use changes'' while its anthropogenic emissions of methane (emissions derived primarily from wet rice cultivation and livestock - estimates from these being highly unreliable) represent nearly half the global total. These greenhouse gas (GHG) emissions represent 30% (28.3 billion metric tons) of the global total of CO2 equivalent emitted in 1989| Per capita GHG emissions are low but per-unit GDP emissions are very high (anywhere from two to six times more than in the OECD countries). The countries participating in the Asia Least Cost Greenhouse Gas Abatement Strategies (ALGAS)(1) project account for nearly 70% of the total CO2 emissions and over 80% of the methane emissions in the entire Asian region. This paper highlights several key issues that must be considered while developing GHG emissions mitigation options within the context of an overall strategy of moving countries rapidly along a path of sustainable development that increases inter-sectoral energy efficiencies within the economy| enhance sinks| and decrease GHG emissions per capita. In particular| this integrated strategy should promote ''no regrets'' policies and emphasize ''win-win'' options that result in sustainable economic development over and above any GHG abatement benefits that might result from the adoption of such initiatives. This emphasis on long term economic sustainability requires a detailed economic evaluation of environmental impacts of potential ALGAS projects. The GHG emissions mitigation potential of the candidate projects must be evaluated within this overall framework of evaluating anticipated economic and environmental impacts. Part 1 of this paper highlights key issues in economic evaluation of environmental impacts and provides recommendations on how to use accepted evaluation techniques during strategic planning and project economic analysis. Project economic analysis incorporates the economic evaluation of environmental impacts. One important set of environmental impacts is that on global climate change through the candidate project's net impacts on GHG emissions. To assess the relative significance of climate change impacts of potential projects| a systematic screening exercise should be adopted during the strategic planning stage. This screening mechanism would allow a comparison of specific climate change impacts relative to other environmental impacts. A monetization of such impacts would then allow an objective assessment of the candidate project's role in mitigation of the impacts of GHG emissions. The special concerns related to development of strategies based on technical estimates and projections of economic parameters that are highly uncertain| are enumerated in Part 1. In addition to recognizing specific economic and political considerations while developing such strategies| the importance of private sector participation in pursuing options for abatement of GHG emissions must be acknowledged. Thus| several private sector specific issues must be factored into overall strategy development; these are discussed in Part 2. 4165,1996,3,3,Strategies for greenhouse gas reduction,Several of the standard gases used in IC manufacturing have been identified as contributors to global warming. Commonly accepted models need to be modified to accurately estimate the impact from a single process gas. Perfluorinated compounds (PFCs)| commonly used in CVD chamber cleans| create particular problems in the atmosphere. A variety of techniques can be used to manage the effluent stream. Recent work has focused on improving reaction efficiencies to reduce the quantity of PFCs. 4243,1996,2,3,Surface thermohaline forcing conditions and the response of the present-day global ocean climate to global warming,I investigate the response of the present-day thermohaline circulation to a greenhouse gas induced global warming under different surface thermohaline conditions in a global Bryan/Cox [Bryan| 1969; Cox| 1989] ocean general circulation model with realistic bathymetry and geometry. Initially the model is spun up With surface temperature and salinity relaxed to Levitus [1982] climatologies. The forcing condition for salinity is then switched to a diagnosed flux| while that for temperature is provided by a restoration with a timescale of either 30 days (strong relaxation) or 300 days (weak relaxation). The present-day ocean climate is obtained under these two sets of thermohaline conditions. Under the strong restoration the modeled North Atlantic Deep Water Formation (NADWF) settles to an intensified state. Under the weak relaxation the model solution hardly differs from that of the spin-up. The ocean states are then subject to a global warming at a rate similar to that of the double CO2 experiment in a fully coupled model described by Manabe and Stouffer [1993| 1994]. The global thermohaline circulations under the weak relaxation show an initial weakening and shallowing| continued weakening upon the cessation of the atmospheric warming| and eventual reestablishment of their strengths. These behavior patterns are not unlike those found in the fully coupled model but are in sharp contrast to those in the case under the strong restoration| where NADWF eventually collapses. The processes responsible for these differences are discussed. 2515,1996,4,4,Surrogate climate-change scenarios for regional climate models,A methodology is presented for generating surrogate climate-change scenarios with a regional climate model. The procedure is simple to implement and dynamically consistent. It entails (i) adopting a realized or simulated atmospheric flow evolution and (ii) prescribing specific thermodynamic modifications of this realization to a regional model's initial fields and externally-specified time-dependent lateral boundaries fields. The resulting scenarios can be used for process and parameterization studies| to calibrate the regional response to a putative global climate change| and to intercompare different models. The approach is illustrated with two month-long regional climate model simulations. The experiment is designed to explore the response within Europe to a pseudo-global warming of 2 K with an accompanying increase in atmospheric water vapor content. Analysis reveals that there is a spatially-differentiated preciptation increase consonant with the domain-averaged increase of about 16% in the water vapor content. 4182,1996,3,2,Technology for removing carbon dioxide from power plant flue gas by the physical adsorption method,Research into technology for removal of CO2 considered to be the major cause of global warming| was applied to electric power plant flue gas. Our method was to use zeolite as adsorbent for physical adsorption| progressing from the previously used PSA (Pressure Swing Adsorption) method to the more advanced PTSA (Pressure and Temperature Swing Adsorption) method. We have been conducting basic research since the 1980s| and in 1991 built a 1000m(3)N/h scale pilot plant| where we are continuing research through trial operation. Trial operation of the pilot plant has been mainly for acquisition of scale up data| as well as improvement in the decrease in the power consumption of PTSA units. As a result| we have seen a better than 20% improvement in that area. In addition| the pilot plant completed 2000 hours of continuous operation without incident between October and December| 1994. The total hours of operation of the plant have topped 4000 hours| but we have seen no decrease in the effectiveness of the CO2 adsorbent. The SOx in the flue gas was trapped in the lower part of desiccant in PSA-H2O before the process. Some of desiccant reacts to that| but we have prevented any ill effects on the process that might be caused by main units. At this point we would like to report on the results of our research| as well as outline our plants for the future. 4235,1996,2,4,Temperature effects on bioconcentration of DDE by Daphnia,1. Lake temperatures vary with season| latitude| elevation and as a result of thermal pollution. Ln addition| lake temperatures may increase with global warming. Radiotracer experiments were conducted to determine the effects of temperature on the bioaccumulation of lipophilic organic contaminants by zooplankton. Daphnia pulex were exposed to C-14-labelled DDE| a stable metabolite of the organochlorine pesticide DDT| in particle-free water for 24 h. An increase in temperature from 5 to 25 degrees C resulted in a 314% increase in bioconcentration factor (the ratio of contaminant concentration in the organism to contaminant concentration in the water). 2. To mimic the fluctuating temperatures experienced by zooplankton during diel vertical migration| we conducted experiments in which animals were exposed to 25 degrees C for 12 h in the light| then 15 degrees C for 12 h in the dark. Exposure to this fluctuating temperature regime for 48h resulted in a 27-33% increase in bioconcentration factor relative to a constant 20 degrees C control. 3. Live animals accumulated more than twice the amount of DDE than freshly killed animals| indicating that the activity of the organism is important in bioconcentration. This finding sheds light on the possible mechanisms for the increase in bioconcentration at higher constant temperatures. Daphnia pump more water through their branchial chambers at higher temperatures. Thus| if the thoracic limbs are an important site of contaminant uptake| then animals are exposed to more contaminant molecules at higher temperatures. Other possible mechanisms include changes in the thickness of the diffusive boundary layer and changes in cell membrane permeability. 2498,1996,2,4,Temperature| CO2 and the growth and development of wheat: Changes in the mean and variability of growing conditions,The experiment described here resulted from simulation analyses of climate-change studies that highlighted the relative importance of changes in the mean and variance of climatic conditions in the prediction of crop development and yield. Growth and physiological responses of four old cultivars of winter wheat| to three temperature and two carbon dioxide (CO2) regimes (350 or 700 ppmv) were studied in controlled environment chambers. Experimental results supported the previous simulation analyses. For plants experiencing a 3 degrees C increase in day and night temperatures| relative to local long-term mean temperatures (control treatment)| anthesis and the end of grain filling were advanced| and grain and dry matter yields were reduced by 27% and 18%| respectively. Increasing the diurnal temperature range| but maintaining the same mean temperature as the control| reduced the maximum leaf area (27%) and grain yield (13%) but did not affect plant development. Differences among the temperature treatments in both phyllochron interval and anthesis date may have resulted from differences between measured air| and unmeasured plant| temperatures| caused by evaporative cooling of the plants. Thermal time (base=0 degrees C)| calculated from air temperature| from anthesis to the end of grain filling was about 650 degrees C d for all cultivars and treatments. Doubling ambient CO2 concentration to 700 ppmv reduced maximum leaf area (21%) but did not influence plant development or tiller numbers. 4284,1996,2,3,The application of agricultural land rating and crop models to CO2 and climate change issues in Northern regions: The Mackenzie Basin case study,The Mackenzie Basin in northwestern Canada covers approximately 1.8 million km(2) and extends from 52 degrees N to 70 degrees N. Much of the Basin is currently too cool and remote from markets to support a viable agricultural sector| but the southern portion of the Basin has the physical potential to support commercial agriculture. This case study employed agricultural land rating and crop models to estimate the degree to which a CO2-induced global warming might alter the physical potential for commercial agriculture throughout the Basin. The two climate change scenarios considered in this analysis would relax the current constraints imposed by a short and cool frost-free season| but without adaptive measures| drier conditions and accelerated crop development rates were estimated to offset potential gains stemming from elevated CO2 levels and warmer temperatures. In addition to striving for a better understanding of the extent to which physical constraints on agriculture might be modified by climate change| there is a need to expand the research context and to consider the capacity of agriculture to adapt to altered climates. 4132,1996,4,4,The atmospheric fate and impact of hydrochlorofluorocarbons and chlorinated solvents,A very considerable body of data pertaining to the atmospheric behaviour of hydrochlorofluorocarbons (HCFCs) and chlorinated solvents is now available and leads to the following conclusions: (a) these compounds| with the exception of 1|1|1-trichloroethane| make a small or insignificant contribution to stratospheric ozone depletion| global warming| 'photo-chemical smog'| 'acid rain'| or chloride and fluoride levels in precipitation; (b) it seems highly unlikely that the chlorinated solvents degrade in the atmosphere to give chloroacetic acids as major products| as has often been claimed in the literature. 4138,1996,2,3,The effects of climate change due to global warming on river flows in Great Britain,Global warming due to an increasing concentration of greenhouse gases in the atmosphere will affect temperature and rainfall| and hence river flows and water resources. This paper presents results from an investigation into potential changes in river flows in 21 catchments in Great Britain| using a daily rainfall-runoff model and both equilibrium and transient climate change scenarios. Annual runoff was simulated to increase by 2050 by over 20% in the wettest scenarios and decline by over 20% in the driest scenarios - and different catchments respond differently to the same change scenario. Monthly flows change by a greater percentage than annual hows| and under all the scenarios considered there would be a greater concentration of flow in winter. Snowfall| and hence snowmelt| would be almost entirely eliminated. Progressive changes in river flows over the next few decades would be small compared with year-to-year variability| but would be noticeable on a decade-to-decade basis. 4183,1996,4,3,The embodiment of carbon associated with Brazilian imports and exports,National statistics designed to determine domestic greenhouse gas (GHG) emissions usually do not take into account the embodiment of carbon in international trade flows| thus failing to reflect that countries indirectly emit GHG by importing non-energy goods. As a matter of fact| by becoming more services oriented and importing increasing quantities of energy-intensive goods from developing nations| developed nations are transferring part of their carbon emissions to developing economies| with a consequent impact on the global environment. The reduction of carbon emissions in developed nations due to lower energy intensities is of no help for the global warming problem if it is accompanied by increases in carbon emissions in developing nations caused by exports to developed notions. This paper estimates the amount of energy and carbon embodied in the non-energy exports and imports of Brazil for the period 1970-1993 in order to determine whether or not the international trade of carbon rich products is a problem worth addressing in the case of Brazil. The estimates show that the carbon content of exports was considerably higher than that of imports from 1980 on. In 1990 the difference| expressed as a fraction of Brazil's total carbon emissions| was 11.4 percent| or some 8.3 million tonnes of carbon. The significance of these findings for Brazil's future energy and emissions policies is discussed. 4206,1996,3,3,The emerging global-warming market-driver in the energy sector: A status report,The financial institutions have in recent years been progressively awakening to a severe threat inherent in human-enhancement of the greenhouse effect. Insurance companies| and increasingly banks and pension funds| have come to fear that a warming world holds the danger of unmanageable property-catastrophe losses triggered by an increase in extreme climate-related events| plus a spectrum of major knock-on problems for debt and equity investments. This emerging greenhouse market-driver now has major implications for corporate strategy in both the financial and energy sectors. 4218,1996,3,3,The Euro-Quebec Hydro-Hydrogen Pilot Project [EQHHPP]: Demonstration phase,Many large metropolitan areas worldwide have called for an improvement in the air quality| which has deteriorated mainly due to energy systems based on fossil fuels| namely the transport sector. Hydrogen and hydrogen enriched fuels can provide an improvement in the Future. If hydrogen is produced from renewable sources| it will also contribute to the reduction of global warming. Due to the superior properties of hydrogen| with respect to efficiency and environmental characteristics| when burned in specially adapted combustion engines| gas turbines and fuel cells| the present EQHHPP phase focuses on hydrogen applications in Future potential markets related to the transport sector. The overall goal of the demonstration phase of the EQHHPP is to advance hydrogen applications. Studies on hydrogen safety| regulations and acceptability| and on socio-economic aspects of hydrogen use| will support the technological development and demonstration activities. In that framework| various demonstration projects were started in 1992| with funds coming from the European Commission| from the Government of Quebec and from industry and research centres. The demonstration projects mainly concern the utilization of hydrogen in airborne and urban transportation| the time Frame being 1992 to 1997. 4237,1996,2,3,The Great Lakes diversion at Chicago and its implications for climate change,In 1900 the city of Chicago began diverting sizable amounts of water from Lake Michigan to move its sewage down the Illinois River. This diversion launched a series of continuing legal controversies involving Illinois as a defendant against claims by the federal government| various lake states| and Canada who wanted the diversion stopped or drastically reduced. During the past 96 years extended dry periods have lowered the lake levels. Using these dry periods as surrogates for future conditions| their effects on the past controversies were examined as analogs for what might occur as a result of climate change from an enhanced Greenhouse effect. The results reveal that changing socioeconomic factors including population growth will likely cause increased water use| and Chicago will seek additional water from the Great Lakes. New priorities for water use will emerge as in the past. Drier future conditions will likely lead to enhanced diversions from the Great Lakes to serve interests in and outside the basin. Future lower lake levels (reflecting a drier climate) will lead to conflicts related to existing and proposed diversions| and these conflicts would be exacerbated by the consequences of global warming. In any event| a warmer| drier climatic regime will challenge existing laws and institutions for dealing with Great Lakes water issues. 4220,1996,4,4,The greenhouse earth: A view from space,The natural greenhouse effect of the Earth is strongly influenced by the radiative effects of water vapour and clouds in the atmosphere| which control the energy absorbed from the sun| and that lost through thermal emission to space. Any perturbations to the climate balance| for example through so-called 'radiative forcing' due to increasing CO2 amounts| variations in solar constant| or other causes| can be amplified by the feedback processes that involve water in its various phases. The radiative cooling of the Earth in the absence of clouds has recently been shown to be dominated by emission from upper-tropospheric water vapour| in the far infrared portion of the spectrum| and this is illustrated: observations of this radiative flux| and of the distribution of water vapour in the upper troposphere| are urgently needed. The role of clouds is discussed| and it is noted that their response to global warming is not presently unambiguously determined with available models| due to the complexity of competing processes: again| as in the cloud-free case| more accurate global observations are needed. The paper is illustrated by data from satellite experiments| most notably the Earth Radiation Budget Experiment sponsored by NASA. 4180,1996,3,4,The impact of fossil generation advances on the emissions of CO2 in the United States,Today| 72% of electric power in the United States is generated from fossil fuels. Additional capacity being brought online to satisfy increasing demand will be almost entirely fossil-based in the next 10-15 years| despite technological advances in renewables and nuclear generation. The U.S. National Energy Strategy of 1991 called for reductions in global warming potential| as measured in billions of tons of CO2 equivalent| of 10% by the year 2010| and 20% by the year 2030. Achievement of such goals will require emphasis on both transportation and energy industries. The U.S. electric power industry has undertaken a voluntary program to return CO2 emissions to 1990 levels. New generation in the U.S. will emphasize high efficiency options| based for the next 10-20 years largely on combined Rankine and Brayton cycles. Such combined cycles| whether fired by coal or gas| result in significantly higher efficiency. However| the complete solution to the control of CO2 emissions in the U.S. will largely depend on improvements in the installed capacity base which will retain the predominant share of electric generation. Reduction of CO2 emissions| as a consequence of burning less fossil fuel per kW generated| is a near-term option for both developed and developing nations. This paper reviews opportunities for efficiency improvement in existing fossil-fuel plants and the likely deployment of new generation options designed to improve plant efficiency and reduce emissions. It is concluded that the most likely future scenario points to CO2 emissions from generating plants being 34% higher than 1990 by the year 2010. 4226,1996,2,2,The influence of human activities on the distribution of hydroxyl radicals in the troposphere,The free radical reactions occuring in the sunlit troposphere involving methane| carbon monoxide| oxides of nitrogen| ozone and water vapour| generate a distribution of hydroxyl radicals which play a major role in removing many of the trace gases emitted by human activities. The United Kingdom Meteorological Office two-dimensional (altitude and latitude) chemistry transport model is used to describe the trace gas life cycles and the fast photochemistry and hence to calculate the distribution of hydroxyl radicals. The mean concentration of hydroxyl radicals estimated in the lowest 0-12 km of the atmosphere is 1.2 x 10(6) molecules cm(-3) (0.74 x 10(6) molecules cm(-3) over 0-24 km). This concentration is in good agreement with estimates based on the OH radical concentrations required to balance the budgets of methyl chloroform and (CO)-C-14. The two-dimensional model was used to investigate the likely future methane concentrations that would build up in the Intergovernmental Panel on Climate Change IS92a emission scenario over the period up to the year 2050. Because of the decrease in likely future OH radical concentrations due to the influence of human activities| methane concentrations build up significantly faster than emissions. There are therefore important consequences for global warming from human interference in the oxidizing capacity of the troposphere. 4211,1996,5,4,The late Palaeozoic Idusi formation of southwest Tanzania: A record of change from glacial to postglacial conditions,The Idusi Formation forms the basal depositional unit of Karoo basins of southwestern Tanzania. It is defined as the rock unit limited by the unconformable contact with underlying Precambrian metamorphics and the base of the overlying| fluviatile Mpera Sandstone Member of the Mchuchuma Formation. The Idusi Formation is subdivided into the Lisimba Member| comprising diamictites| lutites with dropstones| slump masses and laminites| and the overlying Lilangu Member| consisting of black| pyritic and kerogenous lutites. The type section is at Idusi Gorge| situated 6 km east of Lake Nyasa on 10 degrees 17'50'' S. The thickness of the formation at the type section is 240 m| with the maximum observed thickness being 715 m. Plant fossils and palynological assemblages indicate an Asselian age| probably extending down into the Late Carboniferous. The basal diamictites contain striated and facetted clasts| which identify them as glacial deposits. They are mainly wash-out and slurried tillites and also| less frequently| lodgment tillites. These are overlain by proximal and distal deposits of proglacial lakes| which were laid down during the retreat of the glaciers. Laminates of the upper Lisimba Member demonstrate progressively stronger seasonal control. Further amelioration of the climate| with substantially increased biological production both on land and in the water| is demonstrated by the black lutites of the Lilangu Member. They represent euxinic lake sediments formed during the final deglaciation phase. Deposition of the overlying| coal-bearing Mchuchuma Formation occurred under a temperate climate. The duration of the Late Palaeozoic glaciation is estimated at about 20 to 25 Ma. The last quarter of this time span was characterized by climatic amelioration. Global warming was accompanied by an eustatic rise in sea level and a marked decrease in atmospheric CO2. Copyright (C) 1996 Elsevier Science Ltd 2468,1996,4,2,The migration of sessile organisms: A simulation model with measurable parameters,Palaeoecologists have shown that trees migrated at rates of 100 - 1000 m/yr in response to post-glacial warming. In order to predict the impact of forecast anthropogenic climate changes upon forest ecosystems we need to simulate how trees may migrate in response to the changes predicted for the next 1 - 2 centuries. These predictions must rake account of the impacts upon migration of human land-use and habitat fragmentation. We have developed a spatially-explicit mechanistic model (MIGRATE) able to simulate the migration of a single species across a realistically heterogeneous landscape. MIGRATE uses biological parameters that readily may be estimated from data in the literature or from field studies| and represents the landscape as a grid of cells| each with an associated carrying capacity. A one-dimensional version of MIGRATE has been compared both with Skellam's (1951) diffusion model and with the more recent analytical models of van den Bosch et al. (1990| 1992); despite its fundamentally different approach| MIGRATE provides comparable estimates of migration rates| given equivalent input parameters. An example is described that demonstrates the ability of the two-dimensional version of MIGRATE to simulate the likely pattern of spread of a species across a heterogeneous landscape. It is argued that MIGRATE| or models like it| will play a central role in a spatially-hierarchic modelling strategy that must be developed if we are to achieve the goal of simulating the likely response of trees| and other organisms| to both global climate change and the increasing pressures of human land-use.
2502,1996,3,3,The modelling of policy options for greenhouse gas mitigation in India,Greenhouse gas (GHG) emissions in India have important implications for global climate change. Emission trajectory and mitigation policies for India are analyzed using two models| a bottom-up energy systems optimization model (MARKAL) and a top-down macroeconomic model (Second Generation Model (SGM)). MARKAL is used to analyze technologies| peak electricity demand| carbon taxes| and a range of different policy scenarios. Carbon taxes and emissions permits are analyzed using SGM. In the reference scenario| energy use and carbon emissions increase nearly fourfold between 1995 and 2035. The analysis indicates that investment in infrastructure can substantially lower energy intensity and carbon intensity. A high carbon tax induces the substitution of natural gas and renewable energy for coal| and also causes a significant decrease in gross national product and consumption. The limitations of present models for analyzing mitigation policies for developing countries are discussed. Improvements for realistic representation of developing country dynamics and a policy agenda for GHG mitigation studies in developing countries are proposed. 4142,1996,3,3,The necessity of solar energy,The idea of limits to growth has| understandably| achieved notoriety since the days of Malthus and| more recently| the Club of Rome. However| there must be some limits to the ability of the Earth to sustain a growing population. Fortunately| population models suggest that the world's population will probably level out at about two to three times the present numbers over the next hundred years. The question is whether the Earth's resources are sufficient to sustain that population at a high standard of living for all. In this the key issue is energy. It is clear that present trends in energy consumption| especially oil| cannot be sustained much longer. Regardless of this| however| prudence demands a drastic reduction in fossil fuel consumption| in view of the possibility of global warming. It can be shown that| combined with greatly improved energy efficiency| a transition to a solar (renewable) energy based economy capable of sustaining the anticipated growth in the world economy| is possible|bur the constraints are extremely tight. 4172,1996,2,4,The potential effect of global warming on the geographic and seasonal distribution of Phlebotomus papatasi in Southwest Asia,The distribution of Phlebotomus papatasi in Southwest Asia in thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming| temperature values for 115 weather stations were increased by 1 degrees C| 3 degrees C| and 5 degrees C| and the outcome variable coded as unknownin the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May| June| July| and August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations| 71 (62%) would be considered endemic with current temperature conditions; 14 (12%) additional stations could become endemic with an increase of 1 degrees C| 17 (15%) more with a 3 degrees C increase; and 12 (10%) more (all but one station) with a 5 degrees C increase. In addition to increased geographic distribution| seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3 degrees C rise in temperature and in 29 (25%) locations with a 5 degrees C rise. 4101,1996,2,4,The Purple Saxifrage| Saxifraga oppositifolia| in Svalbard: Two taxa or one?,Several studies have demonstrated high levels of genetic (DNA)| ecophysiological| ecological| and morphological variation within the species Purple Saxifrage| Saxifraga oppositifolia| in Svalbard. It has recently been proposed that S. oppositifolia is represented by two conspicuously different subspecies in this archipelago: ssp. reptans| a late-flowering| prostrate ecotype of snow-protected| damp habitats| and ssp. pulvinata| an early-flowering| cushion-like ecotype of dry| wind-exposed heaths and ridges. It has also been suggested that the subspecies may be differentiated at the tetraploid and diploid levels| respectively| which would promote reproductive isolation. These hypotheses are tested by examining variation in morphology| ecology| and pollen size and stainability in 150 plants of S. oppositifolia growing in 50 vegetation samples at four sites in the Kongsfjorden area. Although analyses of the various data sets demonstrated the large variation within the species| the material could not be separated into distinct groups. The morphological variation was continuous along local ecological gradients. The pollen grains were fully stainable and the pollen diameter data showed a unimodal distribution| suggesting that the plants analysed represent only one ploidal level. These results reject a hypothesis that the morphologically intermediate plants are hybrids between two taxa at different ploidal levels. Thus| the conspicuous variation in S. oppositifolia in Svalbard probably results from local| in situ ecoclinal differentiation. Although this variation clearly is without taxonomic significance| it is important in the broader context of arctic conservation biology and the potential impact of global warming on arctic vegetation. 4265,1996,3,3,The quiet (energy) revolution - Analysing the dissemination of photovoltaic power systems in Kenya,The widespread introduction and adoption of renewable energy technologies remains high on virtually every national development policy agenda; renewable energy systems can assist national energy autonomy| decentralize resource management| promote environmental conservation| and serve as a means to reduce global warming. The track record of efforts to turn this noble ideology into successful technology transfer and dissemination| however| remains very mixed. It is a story of a few successes amid many failures. Here we document and examine the diffusion of small-scale photovoltaic (PV) systems in Kenya. At the same time that integrated energy plans and top-down models championing renewable energy futures are becoming increasingly common| a new power base| divorced from these grand schemes| has begun to emerge. Over the past decade| some 20 000 to 40 000 small PV systems| essentially all privately financed| have been installed in Kenya. Many valuable lessons for renewable energy research can be found here. The Kenyan case richly illustrates the dramatic role that actors on every scale| from grassroots to international| can have in accelerating - or when mismanaged| impeding - technology transfer and the elevation of renewable energy systems from niche applications to a prominent role in household empowerment| and decentralized and sustainable development initiatives. 4115,1996,2,4,The role of climate variability and global warming in the dieback of Northern Hardwoods,The severity of dieback in Northern Hardwood Forests of Canada and the United States this century (1910-1990) was reconstructed from pathology records and compared to indices of extreme weather stresses in the region| and to changes in global temperatures and climatic variability over the same period. Thaw-freeze and root-freeze events in winter and early spring were key factors in triggering (and synchronizing) severe episodes of dieback. Once trees were injured by freezing| forest dieback correlated significantly with heat and drought stress. Freezing (but not drought) stresses in Northern Hardwoods correlated significantly (r = 0.70| p < 0.001) with increasing global mean annual temperatures and low values of the Pacific tropical Southern Oscillation Index. Major diebacks did not occur early in the century at a time of notable freezing stress. Prior to 1940| the Northern Hardwoods consisted of relatively young populations of trees regrowing following extensive cutting and forest burning in the late 19th century (1860-1890). It appears that forest maturation is the key factor preconditioning trees to climatic injury| and dieback. A simple projection of climate and forest maturation ages suggested the recurrence of major dieback episodes on white/yellow birch| sugar maple and red spruce in the latter half of the 21st century (2045-2085). 4272,1996,3,3,The secondary benefits of CO2 abatement: How much emission reduction do they justify?,The combustion of fossil fuels emits a range of damaging pollutants| the emissions of which are reduced if fossil fuel use is reduced in order to achieve CO2 abatement. These reductions are termed the secondary benefits of such abatement. The paper reviews estimates of the size of these benefits. Although the estimates are few and uncertain| they uniformly suggest that the secondary benefits are of the same order of magnitude as the gross costs of medium to high levels of CO2 abatement| and are substantially larger than the (equally uncertain) estimates of the primary benefits of CO2 abatement| except where these benefits derive from consideration of damages from unabated global warming in the very long term. The paper concludes that the existence of significant secondary benefits greatly reinforces the economic case for an aggressive policy of CO2 abatement. 4212,1996,4,2,The spatial response of the climate system to explosive volcanic eruptions,Determining the spatial response of the climate system to volcanic forcing is of importance in the development of short-term climate prediction and in the assessment of anthropogenic factors such as global warming. The June 1991 eruption of the Philippine volcano| Mount Pinatubo| provides an important opportunity to test existing understanding and extend previous empirical analyses of the volcanic effect. We identify the spatial climate response to major historic eruptions in the surface air temperature and mean-sea-level pressure record and use this information to assess the impact of the Pinatubo eruption. The Pinatubo eruption clearly generated significant global cooling during the years after the event. The magnitude and timing of the cooling is similar to that associated with previous equatorial eruptions. There is good agreement between the spatial patterns of temperature and circulation anomalies associated with the historic eruptions and those following the Mount Pinatubo event. Evidence of limited higher latitude warming and a major change in the atmospheric circulation is found over the Northern Hemisphere during the first winter after the equatorial eruptions analysed| followed by widespread cooling| but limited change in the atmosphere circulation| during the subsequent 2 years. 2491,1996,2,4,The suitability of montane ecotones as indicators of global climatic change,Because of the difficulties involved with separating natural fluctuations in climatic variables from possible directional changes related to human activities (e.g.| heightened atmospheric CO2 concentrations related to fossil fuel consumption)| some researchers have focused on developing alternative indicators to detect hypothesized climate changes. It has| for example| been suggested that the locations of ecotones| transitions between adjacent ecosystems or biomes| should be monitored. It is assumed that changes in climate| especially increases in atmospheric temperature| will result in shifts in the location (altitude or latitude) of ecotones as plants respond to the newly imposed climatic conditions. In this article| we address the use of two montane ecotones| the alpine tree-line ecotone and the deciduous/Boreal forest ecotone| in monitoring global climatic change. In so doing| we 1) outline the factors that create and maintain each ecotone's position at a given location; 2) assess the projected response of the ecotones to various aspects of global warming; and 3) discuss the usefulness of both ecotones as indicators of global climate change. While it is likely that extended periods of directional climate change would bring about an altitudinal shift in the ranges of montane species and the associated ecotones| we question whether the response at either ecotone will be at a timescale useful for detecting climate change (a few decades) owing to disequilibrium related to upslope edaphic limitations and competitive interactions with established canopy and subcanopy individuals. Further| limitations related to the prediction of the complex and interacting effects of projected changes in temperature| precipitation and site water balance on photosynthetic processes of plant species raise uncertainties about the expected responses of both ecotones. 4274,1996,2,4,Thermal limits to salmonid distributions in the rocky mountain region and potential habitat loss due to global warming: A geographic information system (GIS) approach,The present distribution of salmonid fishes in Wyoming streams was found to be limited to regions where mean July air temperatures did not exceed 22 degrees C. Much of the present salmonid habitat in streams is predicted to be lost if climatic warming occurs. For increases of 1| 2| 3| 4| or 5 degrees C in mean July air temperature| the geographic area of Wyoming containing suitable salmonid habitat would be reduced by 16.2| 29.1| 38.5| 53.3| or 68.0%| respectively. This loss of geographic range would correspond to reductions of 7.5| 13.6| 21.0| 31.4| or 43.3% in the length of streams having suitable salmonid habitat. In the Rocky Mountain region| increases of 1| 2| 3| 4| or 5 degrees C in mean July air temperature would reduce the geographic area containing suitable salmonid habitat by 16.8| 35.6| 49.8| 62.0| or 71.8%| respectively. As warming proceeds| salmonid populations would be forced into increasingly higher elevations and would become fragmented as suitable habitat for coldwater fish becomes separated from main river channels and restricted to headwater streams. A geographic information system (GIS) proved useful for combining the various databases necessary to assess the potential impact of global warming on salmonid populations. 4096,1996,4,6,Time-delayed response of the solar total irradiance variation to long-term solar magnetic cycle amplitude modulation as inferred by sunspot relative number and isotope data of Be-10 in the Greenland ice core and land air temperature variation of the earth,We found that the time profile of the land air temperature anomalies followed the time profile of the magnetic field variation with remarkable similarity and delay time of about 200 years for both cases of the instrumentally measured temperature data and the data reconstructed from tree ring growth rates of the northern north American continent and the polar Ural mountains of northern Siberia. If this is indeed the case| (i) the present global warming will turn to global cooling in near future. If we assume that the land air temperature anomalies can be a good proxy of the solar total irradiance variation| the present result means that (ii) the present global warming of the Earth is a result of release of heat which has been stored in the solar convection zone in the Maunder Minimum in the 17th century. 4177,1996,2,4,Total carbon and nitrogen in the soils of the world,The soil is important in sequestering atmospheric CO2 and in emitting trace gases (e.g. CO2| CH4 and N2O) that are radiatively active and enhance the 'greenhouse' effect. Land use changes and predicted global warming| through their effects on net primary productivity| the plant community and soil conditions| may have important effects on the size of the organic matter pool in the soil and directly affect the atmospheric concentration of these trace gases. A discrepancy of approximately 350 x 10(15) g (or Pg) of C in two recent estimates of soil carbon reserves worldwide is evaluated using the geo-referenced database developed for the World Inventory of Soil Emission Potentials (WISE) project. This database holds 4353 soil profiles distributed globally which are considered to represent the soil units shown on a 1/2 degrees latitude by 1/2 degrees longitude version of the corrected and digitized 1:5 M FAO-UNESCO Soil Map of the World. Total soil carbon pools for the entire land area of the world| excluding carbon held in the Litter layer and charcoal| amounts to 2157-2293 Pg of C in the upper 100 cm. Soil organic carbon is estimated to be 684-724 Pg of C in the upper 30 cm| 1462-1548 Pg of C in the upper 100 cm| and 2376-2456 Pg of C in the upper 200 cm. Although deforestation| changes in land use and predicted climate change can alter the amount of organic carbon held in the superficial soil layers rapidly| this is less so for the soil carbonate carbon. An estimated 695-748 Pg of carbonate-C is held in the upper 100 cm of the world's soils. Mean C:N ratios of soil organic matter range from 9.9 for arid Yermosols to 25.8 for Histosols. Global amounts of soil nitrogen are estimated to be 133-140 Pg of N for the upper 100 cm. Possible changes in soil organic carbon and nitrogen dynamics caused by increased concentrations of atmospheric CO2 and the predicted associated rise in temperature are discussed. 4259,1996,2,4,Trends of some airborne tree pollen in the Nordic countries and Austria| 1980-1993 - A comparison between Stockholm| Trondheim| Turku and Vienna,Long term trends in the occurrence of airborne pollen might help in elucidating the probability or unlikelihood of developments which have been predicted in theory such as global warming or forest decline. We have investigated and compared the trends over a 14 year period (1980-1993) of five selected common tree pollen types (Alnus| Corylus| Betula| Pinus| and Ulmus) from three sites in North Europe (Stockholm| Trondheim| Turku) and one in Central Europe (Vienna) in terms of the start| peak| end| and duration of the season| peak values and annual totals| using data from the European pollen data bank. The existence of trends has been investigated by calculating correlation against years and the statistical significance of the regression lines has been examined at the 5% probability level (p <0.05). A consistent trend in the earlier commencement of the flowering season is observed in all cases| as well as an earlier incidence of peak days. A marked trend to an earlier end of the season was also found in the majority of cases. In most cases| the length of the season showed a trend towards prolongation although this was not significant. Both the peak values and the annual totals exhibit clear trends towards higher values. Since both the start of the season and peak days are primarily temperature-dependant| the clear trends towards an earlier start and peak day in practically all the pollen types and sites examined supports the theory of global warming or| at least| a temporary rise in air temperature over the seasons covered by this investigation. The same conclusion can be drawn from the fact| that most of the trends of pollen frequency show an increase in the number of airborne pollen grains. It was not possible to comment on the possibility of forest decline| as there is insufficient knowledge on the influence of environmental factors on pollen production. Our material shows no trends which are distinct and consistent enough in terms of either decreasing or increasing annual totals or peak values to throw light on the question of forest decline. 2486,1996,2,4,Tropical cyclones and coastal inundation under enhanced greenhouse conditions,The behavior of tropical cyclones under enhanced greenhouse conditions has been the subject of considerable speculation Typical spatial scales of these cyclones are on the order of tens to hundreds of kilometers. Therefore they cannot be simulated in global climate models with resolutions of several hundred kilometers. Thus speculation has been largely based on extrapolation from their present observed distribution| and on simple parametric relationships. However| the conditions under which tropical cyclones from| the intensities they reach| and their usual paths depend on a number of dynamic and thermodynamic factors that may change in complex ways with changing climate. Recent studies using finer resolution global and regional climate models| sensitivity studies that model individual cyclones| and parametric studies have been reviewed. These suggest that the future behavior of tropical cyclones remains an open question with changes of either sign possible in numbers and intensities. The paper also describes the combined effect on coastal inundation of mean sea level rise and changes in storm surges due to tropical and extratropical cyclones. Impact studies highlight the importance of taking both these factors into account and the highly site-specific nature of the problem. 4111,1996,3,3,Urban reactions to the global warming issue: Agenda setting in Toronto and Chicago,Little research has been done about what cities could or should do concerning potential global warming. A few cities have adopted programs to deal with impacts they perceive may occur| and a worldwide network of 100 cities involved with CO2 reduction has recently emerged. Global warming is a new issue for cities and most are only dimly aware of how it may affect them. Toronto| through the efforts of a few leaders| has become a pioneer in the development of an urban response program to global warming. It has charged a city agency to deal with global warming issues| in particular emissions reduction. Chicago is aware of the issue and is concerned about the negative impacts global warming could produce. While behind Toronto| Chicago is moving forward in a number of areas. These two cities illuminate the policy-making process for global warming at the urban level and the role 'policy entrepreneurs' can play at this level. In comparing the two cities| a common model of policy development is utilized. 4255,1996,2,4,Variation of snow| winter precipitation and winter air temperature during the last century at Nagaoka| Japan,Reduced amounts of snow in the eight winters from 1986-87 to 1993-94 at Nagaoka| Japan| seem to he due to a winter air-temperature rise. The winter air temperature has shown a cyclic variation with a gradual increase in the past 100 years. The linear rate of the temperature rise in the past century was calculated as 1.35 degrees C per 100 years. Both the maximum snow depth and winter precipitation showed an inversely positive correlation with winter mean air temperature. The square of the statistical correlation coefficient r(2) was calculated as 0.321 and 0.107| respectively. Statistically smoothed curves of the maximum snow depth and winter precipitation showed maximum values in 1940. Fluctuations in deviation of the maximum snow depth showed smaller values than in precipitation. The minimum winter mean air temperature obtained from a 10 year moving average curve was found in 1942| and the deviation from the climatic mean changed from negative to positive in 1949. The change in sign of the temperature deviation and the increase of the deviation may be attributable to global warming. 4128,1996,2,4,Vulnerability and adaptation of the larch forest in eastern Siberia to climate change,The most widely distributed coniferous forests in the world are the larch forests. In the Russian Federation they occupy 27.6 x 10(6) ha. In Siberia| the larch species Larix russica generally grows west of the Yenissei River| and Larix gmelinii grows to the east. The morphological and physiological features oft. gmelinii make it possible for this species to grow in the far north of eastern Siberia| where climate conditions are more severe: The range of air temperature fluctuations in this region is more than 100 degrees C| from 38 degrees C down to 64 degrees C below zero. One of the major adaptions to unfavorable soil conditions is provided by a specific feature of root formation in L. gmelinii| in which the apex central root dies off at the permafrost border and a root system develops in upper soil layer. The major larch vulnerability factors are natural and anthropogenic fires and damage caused by insects| which become more frequent with hot and dry weather. The consequences of projected global warming could be both positive and negative for larch forests. Permafrost melting may result in improved soil nutrition in the areas the larch forests occupy| yet the frequency of forest fires and damage by pathogens are likely to increase. Global warming is expected to cause forest dieback and increased areas of steppe in the southern regions of eastern Siberia. 4130,1996,4,3,Vulnerability assessment of Angat water reservoir to climate change,Global warming due to an anticipated doubling of carbon dioxide concentration in the atmosphere is expected to alter the earth's climate system within the next century. The potential changes in the climate system could affect hydrological cycles and processes. Possible impacts of climate change on water resources should be assessed to evaluate probable adaptation measures. In the Philippines| a preliminary assessment of the vulnerability of water resources to climate change and variability was undertaken. For this particular study| the Angat Reservoir was chosen as the study area Because of its socioeconomic importance| it is useful to assess its vulnerability to climate change. A rainfall-runoff simulation model| WATBAL| was used to determine the effect of temperature and rainfall changes| based on CO2 doubling| on inflow to the reservoir. Climate change scenarios developed from results from three general circulation models and incremental changes were used. The results showed that changes in temperature and rainfall could affect runoff either positively or negatively. Using the temperature and rainfall changes from the Geophysical Fluid Dynamics Laboratory model there was a 32% increase in runoff and with the Canadian Climate Centre Model| thee was a 15% decrease in runoff. Under a climate scenario generated by the United Kingdom Meteorological Office model| runoff is estimated to increase by 5%. The use of incremental scenarios revealed the strong sensitivity of runoff to changes in rainfall as compared with changes in temperature. 2524,1996,2,3,Vulnerability assessment of water resources in Egypt to climatic change in the Nile Basin,The impacts of global climate change on the water resources of the Nile River Basin were evaluated using simulation models. Four climate change scenarios were evaluated (baseline| GISS| GFDL| and UKMO). The complete impact of climatic changes in the Nile cannot be fully predicted with confidence| as some models forecast increased flows| while others project significant decreases. However| it was observed that the Nile River flow is extremely sensitive to ambient temperature and precipitation changes| and it is possible that the effects of climatic fluctuations would be severe. Several water management options were identified to help adapt Nile River management to a changing global climate. 2525,1996,2,3,Vulnerability of forest resources to global climate change: Case study of Cameroon and Ghana,The response and feedbacks of forest systems to global environmental change| including the ecosystems of West Africa| are expected to be profound. A comparative assessment of current and future forest distribution in Cameroon and Ghana in response to land-use change and global climate change was completed. From 1970 to 1990| the forest area of Cameroon and Ghana declined dramatically due to harvesting and degradation| averaging 0.6 and 1.3% each year| respectively. The areal distribution of West African forest systems is projected to shift 5 to 15%| based on 4 General Circulation Model (GCM) scenarios and the Holdridge Life Zone Classification System. Loss of forest habitat due to destruction| degradation and climate change is projected to increase animal and plant species loss. Adaptation of evergreen and deciduous forest systems to global environmental change poses many challenges for Cameroon and Ghana. Application of low-input| indigenous resource management options| which have been practiced on a sustained basis for centuries| may be a feasible adaptation goal. 2487,1996,2,4,Vulnerability of Sri Lanka tea production to global climate change,The tea industry is Sri Lanka's main net foreign exchange earner and source of income for the majority of laborers. Tea yield is greatly influenced by weather| and especially by droughts| which cause irreparable losses because irrigation is seldom used on tea plantations. At the other extreme| heavy rains erode top soil and wash away fertilizers and other chemicals. In the recently published Sri Lanka country report on climate change| it was reported that the island will experience extreme rainfall intensities and warmer temperatures as a result of climate change. The possibility of a 10% increase in the length of dry and wet seasons per year in the main plantation area was also indicated. Thus both drought damages and soil losses in tea production areas will increase in the years to come. An analysis of the results of field experiments with weather data shows that increases in temperature| soil moisture deficit| and saturation vapor pressure deficit in the low elevations will adversely affect growth and yield of tea Reports have also shown that about 30 cm of soil has already been eroded from upland tea plantations. Under these circumstances| the tea industry in Sri Lanka is clearly vulnerable to predicted climate changes| and subsequently greater economic| social| and environmental problems. This paper discusses the various aspects of the adverse effects of climate change on Sri Lanka's tea industry. 4233,1996,2,4,Vulnerability of the coastal zone of The Gambia to sea level rise and development of response strategies and adaptation options,The coastal zone of The Gambia consists of 70 km open ocean coast and 200 km sheltered coast. Only about 20 km of the open coastline is significantly developed and this includes Banjul (the capital city)| Bakau and Cape St. Mary| Fajara and the Tourism Development Area (TDA). Tourism is the most important economic sector in the coastal zone and contributes about 10% of the government revenue. Fisheries and agriculture are also important coastal industries. In this study the Aerial Videotape-assisted Vulnerability Analysis (AVVA) technique has been used to provide a detailed analysis of vulnerability to sea level rise| and adaptation strategies have been identified. The data used includes a video recording of the coastline| color infrared and black and white aerial photography| topographic maps| bathymetric maps| a geological map of The Gambia and still photographs. The data have been used to characterize the coastal zone into 9 geomorphological units| wherein the cultural and heritage sites of economic importance have been delineated and characterized according to their biophysical and economic importance. Future erosion rates have been projected by applying the Bruun Rule| and future total land loss due to inundation in response to global warming and accelerated sea level rise has been determined. The sea level rise scenarios considered are 0.2 m| 0.5 m| and 1.0 m per century. Inundation is estimated to be about 92.32 x 10(6) m(2) for a 1.0 m sea level rise| 45.89 x 10(6) m(2) for a 0.5 m sea level rise and 4.96 x 10(6) m(2) for a 0.2 m sea level rise. The greater part of this area lost will be wetlands and mangrove systems important for fish spawning areas and habitats for wildlife. Shoreline retreat is estimated to vary between about 6.8 m in cliffy areas to about 880 m for more flat and sandy areas based on the Bruun Rule. Population and physical structures at risk have been determined. Attempts have been made to report this loss in monetary terms| but firm figures are not yet available. Only one unit of the coastal zone has been evaluated. In this unit| it is expected that the capital city will be completely lost through both erosion and inundation within 50 to 60 yr with a total of 42000 persons displaced. Lands and physical structures to be lost are estimated at US$ 217 million. Response strategies and adaptation options identified include: innovative sand management| building and rehabilitation of groins| construction of revetments to protect important areas| construction of sea-walls/bulkheads| public outreach and awareness| building regulations and urban growth planning| wetland preservation and mitigation| and development of a coastal zone management plan. 2522,1996,2,3,Vulnerability of Zimbabwe forests to global climate change,The impacts of global climate change on forest distribution was evaluated using the Holdridge life zone and GISS general circulation model scenarios. Across Zimbabwe| 17 to 18% of the total land area is projected to shift from subtropical thorn woodland and subtropical dry forest to tropical very dry forest under the GISS scenario. The projected shift in forest distribution is attributable to a future decline in precipitation patterns and an increase in ambient temperature. 4127,1996,2,4,Water reserves in soils as affected by global climatic warming: Example forecast for eastern Europe,With the awaited global warming by 1 degrees C| the same water reserves in spring will be proper to tundra| podzolic| sod-podzolic| gray forest soils and chernozems. They will be higher by 100-150 mm in chestnut| cinnamonic| and brown semidesertic soils. The maximum summer drying is thought to result in a decrease of water reserves by 30-50 mm in tundra soils and by 50-80 mm in taiga ones. There will be no changes in steppe zone while| in dry-steppe| water reserves will increase by 20-60 mm. If the mean global temperature rises by 2 degrees C| water reserves will be the same as in the previous case in spring| whereas a decrease by 40-60 mm in summer is probable for sod-podzolic soils and an increase by 50-60 mm may be expected in the dry-steppe zone. 4248,1996,2,4,Waterfront planning and global warming,Waterfronts today are valuable untapped resources with great potential for reshaping our region. The vast stretches of shoreline that lie unused in the wake of industrial decline and transportation changes (ref. I . p. I) have created opportunity and challenge for the future.
Coastal and waterfront development became popular in the 1960s (ref. 2| p. 10) and has increased so that nearly 50 percent of the nation's population lives in the coastal area (ref. 3| p. 1). If global warming occurs| the ever-accelerating development at the shore will pose great risks from both the estimated increase in storms and hurricanes (ref. 4| pp. I | 13| cover) and the rise in sea level (ref. 5. p. 12) with the related floodingand erosion. We are at a critical juncture in planning. caught between an increasing market for waterfront development| vast quantities of underused waterfront property| and Mother Nature's lessons of flooding| sea level rise| and global warming.
The questions for waterfront planners are twofold: What is likely to happen on the seemingly unlimited decayed waterfront stretches given the economic and political factors and| secondly| what are some of the ideas surfacing today that address sea level rise and global warming?
4113,1996,3,2,Working fluids for mechanical refrigeration - Invited paper presented at the 19th International Congress of Refrigeration| The Hague| August 1995,The phasing out of fully halogenated halocarbons becomes effective at the end of 1995 by international agreement. Under the same ozone depletion issue| the companion fluids HCFCs are suffering a similar fate| as they are considered controlled substances with a virtual phase-out by 2020| and more drastic reductions may be proposed in the near future. Some international action might also be agreed upon on refrigerants with regard to the threatened environmental emergency of anthropogenic global warming. Therefore| in choosing replacement fluids primary concern must be given to minimising the total warming impact| which| for most applications| calls for improved energy efficiency. During recent years| industry has scrutinised and proposed a number of new synthesised products as immediate drop-in or long-term replacements for fluids harmful to the environment. Together with some single-component new generation refrigerants| quite a few two-component| three-component or even four-component mixtures| both with zeotropic and azeotropic behaviour| are being considered. The main issues associated with the use of the new generation refrigerants are discussed| such as behaviour with oil; flammability; efficient use of temperature glides| fractionation and heat-transfer degradation with zeotropic mixtures. The full environmentally friendly option of resorting to natural fluids is also considered by examining some recent innovative applications as refrigerants of some hydrocarbons| ammonia| carbon dioxide| water and air. Copyright (C) 1996 Published by Elsevier Science Ltd and IIR 4751,1997,4,4,1|1|1|3|3|-pentafluorobutane (HFC-365mfc): Atmospheric degradation and contribution to radiative forcing,The rate constant for the reaction of the hydroxyl radical with 1|1|1|7|7-pentafluorobutane (HFC-365mfc) has been determined over the temperature range 278-323 K using a relative rate technique. The results provide a value of k(OH + CF3CH2CF2CH3) = 2.0 X 10(-12) exp(- 1750 +/- 400/T) cm(3) molecule(-1) s(-1) based on k(OH + CH3CCl3) = 1.8 X 10(-12) exp (- 1550 +/- 150/T) cm(3) molecule(-1) s(-1) for the rate constant of the reference reaction. Assuming the major atmospheric removal process is via reaction with OH in the troposphere| the rate constant data from this work gives an estimate of 10.8 years for the tropospheric lifetime of HFC-365mfc. The overall atmospheric lifetime obtained by taking into account a minor contribution from degradation in the stratosphere| is estimated to be 10.2 years. The rate constant for the reaction of Cl atoms with 1|1|1|3|3-pentafluorobutane was also determined at 298 +/- 2 K using the relative rate method| k(Cl + CF3CH2CF2CH3) = (1.1 +/- 0.3) x 10(-15) cm(3) molecule(-1) s(-1). The chlorine initiated photooxidation of CF3CH2CF2CH3 was investigated from 273-330 K and as a function of O-2 pressure at 1 atmosphere total pressure using Fourier transform infrared spectroscopy Under all conditions the major carbon-containing products were CF2O and CO2| with smaller amounts of CF3O3CF3. In order to ascertain the relative importance of hydrogen abstraction from the -CH2- and -CH3 groups in CF3CH2CF2CH3| rate constants for the reaction of OH radicals and CI atoms with the structurally similar compounds CF3CH2CCl2F and CF3CH2CF3 were also determined at 298 K k(OH + CF3CH2CCl2F) = (8 +/- 3) X 10(-16) cm(3) molecule(-1) s(-1); k(OH + CF3CH2CF3) = (3.5 +/- 1.5) X 10(-16) cm(3) molecule(-1) s(-1); k(Cl + CF3CH2CCl2F) = (3.5 +/- 1.5) X 10(-17) cm(3) molecule(-1) s(-1)]; k(Cl + CF3CH2CF3) < 1 X 10(-17) cm(3) molecule(-1) s(-1). The results indicate that the most probable site for H-atom abstraction from CF3CH2CF2CH3 is the methyl group and that the formation of carbonyl compounds containing more than a single carbon atom will be negligible under atmospheric conditions| carbonyl difluoride and carbon dioxide being the main degradation products. Finally| accurate infrared absorption cross-sections have been measured for CF3CH2CF2CH3| and jointly used with the calculated overall atmospheric lifetime of 10.2 years| in the NCAR chemical-radiative model| to determine the radiative forcing of climate by this CFC alternative. The steady-state Halocarbon Global Warming Potential| relative to CFC-11| is 0.17. The Global Warming Potentials relative to CO2 are found to be 2210| 790| and 250| for integration time-horizons of 20| 100| and 500 years| respectively. (C) 1997 John Wiley & Sons| Inc. 2402,1997,2,4,A 200-year record of gale frequency| Edinburgh| Scotland: possible link with high-magnitude volcanic eruptions,Most research concerned with the relationship between volcanic activity and global climate change has focused on the impacts that volcanoes have on atmospheric temperature. Very little attention| however| has been given to the effect of volcanic eruptions on patterns of storminess. Here we present a historical record of gale-day frequency for Edinburgh| Scotland| extending from AD 1780 to 1988 (the Mossman-Hickey chronology)| which we believe represents the longest historical record of gales in Europe. Calculation of gale-day frequency for this time interval shows three clear peaks in storminess that follow the volcanic eruptions of Tambora (1815)| Krakatoa (1883) and El Chichon (1982). It appears that the greatest periods of storminess evident in the Edinburgh record during the last 200 years have taken place during relatively short intervals following major episodes of volcanism. If correct| the processes linking high-magnitude volcanic eruptions to storminess in the North Atlantic need to be included in IPCC research that presently focuses most attention on linkages between increased storminess and the effects of global warming. 4810,1997,2,3,A climate-change scenario for the Columbia River basin,This work describes the method used to generate a climate-change scenario for the Columbia River basin. The scenario considers climate patterns that may change if the atmospheric concentration of carbon dioxide (CO2)| or its greenhouse gas equivalent| were to double over pre-Industrial Revolution values. Given the current rate of increase in atmospheric CO2 concentration| doubling could occur within the next 50 to 100 years. The Columbia River basin is in a transition climate zone between predominating maritime to the west| arctic to the north| and continental to the east. Consequently| it is difficult to characterize through means and averages. Therefore| many of the current stochastic methods for developing climate-change scenarios cannot directly apply to the basin. To circumvent this problem| a composite approach was taken to generate a climate scenario that considers knowledge of current regional climate controls| available output from general circulation and regional climate models| and observed changes in climate. The resulting climate-change scenario suggests that precipitation could increase substantially during winter (+20 to +50 percent) and moderately during spring and autumn (+5 to +35 percent). A slight decrease (0 to -5 percent) in summer precipitation is possible| except for the southeastern portions of the basin that may experience an increase in convective precipitation (+5 percent). Low-elevation (<1 kilometer) temperatures throughout the year may increase 1 to 3 degrees C| with greatest increases during winter. This amount of temperature change is possible because of an expected loss of low-elevation snow cover. At high elevations| increased cloud cover could cause average temperatures to decrease during winter but be synchronized with possible warming at low elevations during summer. The diurnal range of temperature could decrease| especially in summer and autumn. 4777,1997,2,4,A climatological analysis of the Koppen Dfa/Dfb| boundary in eastern North America| 1901-1930,In 1952| Jack Villmow proposed a new and more northerly border for the Dfa/Dfb climate boundary in eastern North America. This paper follows from Villmow's work with an improved data set over a longer period and considers the issue of anthropogenically induced global warming as a possible cause for explaining any change in the boundary. Data were obtained from the Global Historical Climatology Network's Long-Term Monthly Temperature| Precipitation| Sea Level Pressure| and Station Pressure Data Analysis included extracting the annual maximum mean monthly temperature values for 160 weather observing stations Ln the United States and Canada and mapping the 22 degrees C isotherm (Dfa/Dfb boundary) for three 30-year sequential climatological periods beginning with 1901-1930. Although the Dfa/Dfb boundary did vary latitudinally in each 30-year period| no evidence of warming was found in the north central and northeastern US| or the southern peninsula of Ontario over the 30-year period| particularly in the most recent 30-year comparison (1961-1990). 2443,1997,3,2,A comparison of greenhouse gas mitigation options,The mitigation of atmospheric greenhouse gas emissions is important for minimizing the anthropogenic contributions to climate change. These concerns have led to the investigation of many technologies and strategies for mitigation| both in the U.S. and abroad. One technology explored at ANL is integrated gasification combined cycle (IGCC) power generation| which is based on extraction of CO2 by a solvent. The IGCC process reduces CO2 production through efficient fuel use| which makes CO2 recovery less expensive than conventional systems. Recovery using the following solvents was explored in detail: monoethanolamine (MEA)| glycol| chilled methanol| and hot potassium carbonate. Other incentive-based options for mitigation have also been explored| including market incentives (carbon fees and tradable permits) and regulatory measures. Our work suggests a complex global strategy will be necessary to optimize options for mitigation of global climate change| one that takes into account both local and regional considerations. 2459,1997,2,4,A comparison of scenarios for the effect of global climate change on cotton growth and yield,If global surface temperatures change as projected because of radiative and physiological effects of a changing environment| we should expect important changes in crop production in the 21st Century. Experiments were conducted at ambient and twice ambient atmospheric CO2 concentrations at five temperatures. The 1995 temperature in Mississippi was used as a reference with the other temperatures being 1995 minus 2 degrees C| and 1995 plus 2| 5 and 7 degrees C. Daily and seasonal variation and amplitudes were maintained. Seedlings had 4-6 times as much leaf area and dry weight at 20 d after emergence when grown at 28 degrees C as at 23 degrees C (1995 ambient) average temperature during that growth period. Number of days to first square| flower| and open boil decreased as temperature increased. Double atmospheric CO2 did not affect these developmental rates. Temperatures above 28 degrees C| or 1995 average whole-season temperatures| were detrimental to mid-and late-season boil retention and growth. No fruits were retained to maturity at 1995 plus 5 or 7 degrees C. However| whole season vegetative growth was not significantly reduced by temperature 5-7 degrees C above the 1995 ambient conditions. Twice ambient CO2 caused about 40% increase in vegetative dry matter accumulation across temperatures. In a separate experiment| similar results were obtained on fruiting cotton grown at a range of temperatures based on long-term average US Midsouth July temperatures. Therefore| if global warming occurs as predicted| food and fibre production in such high-temperature and humid environments may be more limited to vegetative structures and the animals that consume vegetative structures. 4881,1997,3,3,A comparison of two algorithms for estimating carbon dioxide emissions after forest clearing,The clearing of forest during the last two centuries has contributed to the growth of carbon dioxide in the atmosphere and the prospect of global warming. The OECD| under the auspices of the IPCC| has developed a set of standard procedures for estimating greenhouse gas exchanges| including carbon dioxide exchange from forest clearing and regrowth. We present an alternative algorithm for estimating carbon dioxide exchange from forest clearing and regrowth based on a simple plant/soil model (DCDT) and compare it with the IPCC/OECD algorithm using two worked examples: constant clearing and constant regrowth of a semi-arid mallee forest in Australia. In these examples| the initial and final (equilibrium) carbon in the plant and soil are the same in both algorithms. The algorithms differ in their time scales of response. The IPCC/OECD algorithm| when compared with the DCDT algorithm| overestimates the carbon dioxide emissions from converting mallee forest to wheat cropping by up to 33%| averaged over a decade. The IPCC/OECD algorithm| when compared with the DCDT algorithm| underestimates the emission from regenerating the cleared land by as much as 100% over a decade. These differences arise when the rates of land clearing and regeneration vary on a time scale shorter than that for the biosphere to equilibrate after a land use change or disturbance. This study shows that the improved quantification of the processes of carbon dynamics in the plant/litter/soil system may be as important as improving the mapping of areas cleared and current carbon pools in reducing the uncertainties associated with CO2 emissions from forest clearing. (C) 1997 Elsevier Science Ltd. 4729,1997,3,3,A comprehensive approach to climate change: Political and scientific considerations,The concept of comprehensiveness embedded in the climate convention is discussed with attention to political and scientific considerations that need to be taken into account for this approach to serve as a tool for enhancing the effectiveness of a climate regime. The manners in which the approach may serve as an instrument for facilitating negotiation and implementation of a climate regime are discussed| and an operational definition is suggested. A key question with regard to the employment of a comprehensive approach in climate politics concerns how well methodologies for comparing gases perform. This question is discussed with regard to Global Warming Potentials (GWPs). When the most important greenhouse gases are concerned| we suggest that in the absence of better alternatives| the use of GWPs may serve as a preliminary tool for policy making until better methods are developed. It is emphasized that the choice of time horizon has significant ecological and political implications that should be taken into account. 4765,1997,4,4,A coupled theory of tropical climatology: Warm pool| cold tongue| and walker circulation,Based on results from analytic and general circulation models| the authors propose a theory for the coupled warm pool| cold tongue| and Walker circulation system. The intensity of the coupled system is determined by the coupling strength| the local equilibrium time| and latitudinal differential heating. Most importantly| this intensity is strongly regulated in the coupled system| with a saturation level that can be reached at a modest coupling strength. The saturation west-east sea surface temperature difference (and the associated Walker circulation) corresponds to about one-quarter of the latitudinal differential equilibrium temperature. This regulation is caused primarily by the decoupling of the SST gradient from a strong ocean current. The author's estimate suggests that the present Pacific is near the saturation state. Furthermore| the much weaker Walker circulation system in the Atlantic Ocean is interpreted as being the result of the influence of the adjacent land| which is able to extend into the entire Atlantic to change the zonal distribution of the trade wind. The theory is also applied to understand the tropical climatology in coupled GCM simulations| in the Last Glacial Maximum climate| and in the global warming climate| as well as in the regulation of the tropical sea surface temperature. 4823,1997,2,4,A geophysiologist's thoughts on the natural sulphur cycle,The climate depends on the atmospheric abundance of sulphur aerosols at all levels up to the stratopause. Volcanoes| combustion and biological emissions all contribute and usually result in cooling. The history of this topic is lively and goes back at least to the eighteenth century with Benjamin Franklin's comments on the cooling effects of the sulphuric acid aerosol from the Icelandic volcano| Laki. Mitchell first drew attention to the potential cooling effects of combustion aerosols. Charlson and his colleagues proposed that emissions of dimethyl sulphide (DMS) from ocean algae might also be important. More recently| Lovelock & Kump drew attention to the decline of biological sulphur emissions with global warming and the possible consequence of a positive feedback on climate change. The geophysiological aspects| which arose from the Gaia hypothesis in the early 1970s| form an important part of the account that follows. 4833,1997,2,2,A numerical simulation of anthropogenic climate change,Results are presented from a recent high resolution transient climate change experiment carried out at the Max Planck Institute for Meteorology| Hamburg. The experiment is discussed in the light of the greenhouse warming experiment by Arrhenius| The transient calculation started in January 1860 and continued until the end of the 21st century. The effect of individual greenhouse gases has been incorporated using observed data until 1990 and thereafter assumed emissions according to (IPCC) scenario IS92a. Validation of the coupled model shows a realistic simulation of observed coupled modes such as El Nino-Southern Oscillation. The simulated low frequency variability at middle and high latitudes resembles| by and large| the observed one. A detailed evaluation over Scandinavia shows that the model reproduces the typical very strong interannual variability of this region. The result shows a small warming until present in broad agreement with observations. There is a strong positive feedback with water vapor but a negative feedback with clouds. The evaluation is concentrated at the time the concentration of the greenhouse gases has doubled compared to the starting time. Such a doubling is expected to take place in 2030-2040. The energy cycle is slowly changing and a gradual increase in the absorption of short-wave radiation in the atmosphere and an increase in the net long-wave radiation at the ground are noted. The latent heat flux from the surface of the earth increases while the sensible heat flux decreases. The hydrological cycle increases very slowly and mainly over land. After 1990| a rapid warming is starting which goes on with superimposed minor multidecadal variations until the end of the run. Overall global warming amounts to some 3.5 degrees C for the period 1990 to 2100. At the time of greenhouse gas doubling| the global warming amounts to 1.9 degrees C. The typical feedback pattern for the early part of the run continues with increasing amplitude and so do the changes in the hydrological cycle. The warming pattern shows a strong amplitude in the Arctic associated with a marked retreat of Arctic sea ice. The overall warming over the Scandinavian area is one to two degrees higher than the global average superimposed upon a similar high interannual variability as in the present climate. 4755,1997,4,4,A predictability study of simulated North Atlantic multidecadal variability,The North Atlantic is one of the few places on the globe where the atmosphere is linked to the deep ocean through air-sea interaction. While the internal variability of the atmosphere by itself is only predictable over a period of one to two weeks| climate Variations are potentially predictable for much longer periods of months or even years because of coupling with the ocean. This work presents details from the first study to quantify the predictability for simulated multidecadal climate variability over the North Atlantic. The model used for this purpose is the GFDL coupled ocean-atmosphere climate model used extensively for studies of global warming and natural climate variability. This model contains fluctuations of the North Atlantic and high-latitude oceanic circulation with variability concentrated in the 40-60 year range. Oceanic predictability is quantified through analysis of the time-dependent behavior of large-scale empirical orthogonal function (EOF) patterns for the meridional stream function| dynamic topography| 170 m temperature| surface temperature and surface salinity. The results indicate that predictability in the North Atlantic depends on three main physical mechanisms. The first involves the oceanic deep convection in the subpolar region which acts to integrate atmospheric fluctuations| thus providing for a red noise oceanic response as elaborated by Hasselmann. The second involves the large-scale dynamics of the thermohaline circulation| which can cause the oceanic variations to have an oscillatory character on the multidecadal time scale. The third involves nonlocal effects on the North Atlantic arising from periodic anomalous fresh water transport advecting southward from the polar regions in the East Greenland Current. When the multidecadal oscillatory variations of the thermohaline circulation are active| the first and second EOF patterns for the North Atlantic dynamic topography have predictability time scales on the order of 10-20 y| whereas EOF-1 of SST has predictability time scales of 5-7 y. When the thermohaline variability has weak multidecadal power| the Hasselmann mechanism is dominant and the predictability is reduced by at least a factor of two. When the third mechanism is in an extreme phase| the North Atlantic dynamic topography patterns realize a 10-20 year predictability time scale. Additional analysis of SST in the Greenland Sea| in a region associated with the southward propagating fresh water anomalies| indicates the potential for decadal scale predictability for this high latitude region as well. The model calculations also allow insight into regional variations of predictability| which might be useful information for the design of a monitoring system for the North Atlantic. Predictability appears to break down most rapidly in regions of active convection in the high-latitude regions of the North Atlantic. 4715,1997,2,3,A scenario of storm surge statistics for the German bight at the expected time of doubled atmospheric carbon dioxide concentration,Past variations of water levels at Cuxhaven| Germany (German bight)| are examined| and a scenario for future changes due to expected global warming is derived. The observational record of Cuxhaven water levels features a linear upward trend in the annual mean water level of about 30 cm 100 yr(-1) overlaid by irregular variations due to synoptic disturbances. These irregular storm-related variations are shown to have remained mostly stationary since the beginning of observations until today. A scenario for future conditions is derived by means of a two-step downscaling approach. First|a ''time slice experiment'' is used to obtain a regionally disaggregated scenario for the time mean circulation for the time of expected doubling of atmospheric CO2 concentrations. Then| an empirical downscaling model is derived| which relates intramonthly percentiles of storm-related water-level variations at Cuxhaven to variations in the monthly mean air pressure field over Europe and the northern North Atlantic. Past variations of storm-related intramonthly percentiles are well reproduced by the downscaling model so that the statistical model may be credited with skill. The combined time slice-statistical model ''predicts|'' for the expect time of doubled atmospheric CO2 concentrations in the decade around 2035| an insignificant rise of the 50%| 80%| and 90% percentiles of storm-related water-level variations in Cuxhaven of less than 10 cm| which is well within the range of natural interdecadal variability. These numbers have to be added to the rise in mean sea level due to thermal expansion and other slow processes. 4877,1997,3,3,A study of the role of end-of-pipe technologies in reducing CO2 emissions,Reducing CO2 emissions to cope with global warming is one of the most challenging issues for the global energy system in the 21(st) century. To deal with the tremendous challenge| we should promote long range global efforts keeping in mind the wide scope of technological possibilities. (C) 1998 Elsevier Science Ltd. All rights reserved. 4788,1997,4,3,A tropical influence on global climate,A potential influence of tropical sea surface temperature on the global climate response to a doubling of the CO2 concentration is tested using an atmospheric general circulation model coupled to a slab mixed layer ocean. The warming is significantly reduced when sea surface temperatures in the eastern equatorial Pacific cold tongue region between latitudes 2.25 degrees N and 2.25 degrees S are held at the control simulation values. Warming of the global mean temperature outside of the cold tongue region is reduced from 2.4 degrees C in the unconstrained case to 1.9 degrees C when the sea surface temperature constraint is applied. The decrease in the warming results from a positive net heat flux into the ocean cold tongue region and implicit heat storage in the subsurface ocean| induced by horizontal atmospheric heat fluxes. The reduced surface temperature warming outside of the cold tongue region is due to reduction in the downward longwave radiative flux at the surface| caused in turn by reduced atmospheric temperature and moisture. The global mean surface temperature responds to the heat storage in the ocean as if the global mean radiative forcing due to the doubled CO2 (approximately 4 W m(-2)) was reduced by the value of che global mean heat flux into the ocean. This mechanism also provides a possible explanation for the observed high correlation on interannual timescales between the global mean tropospheric temperature and sea surface temperature in the eastern tropical Pacific. The results emphasize the importance of correctly modeling the dynamical processes in the ocean and atmosphere that help determine the sea surface temperature in the equatorial eastern Pacific| in addition to the thermodynamical processes| in projecting global warming. 2413,1997,4,4,A watershed approach to ecosystem monitoring in Denali National Park and Preserve| Alaska,The National Park Service and the National Biological Service initiated research in Denali National Park and Preserve| a 2.4 million-hectare park in southcentral Alaska| to develop ecological monitoring protocols for national parks in the Arctic/Subarctic biogeographic area. We are focusing pilot studies on design questions| on scaling issues and regionalization| ecosystem structure and function| indicator selection and evaluation| and monitoring technologies. Rock Creek| a headwater stream near Denali headquarters| is the ecological scale for initial testing of a watershed ecosystem approach. Our conceptual model embraces principles of the hydrological cycle| hypotheses of global climate change| and biological interactions of organisms occupying intermediate| but poorly studied| positions in Alaskan food webs. The field approach includes hydrological and depositional considerations and a suite of integrated measures linking key aquatic and terrestrial biota| environmental variables| or defined ecological processes| in order to establish ecological conditions and detect| track| and understand mechanisms of environmental change. Our sampling activities include corresponding measures of physical| chemical| and biological attributes in four Rock Creek habitats believed characteristic of the greater system diversity of Denali. This paper gives examples of data sets| program integration and scaling| and research needs. 4817,1997,4,5,A winning coalition of advocacy: climate research| bureaucracy and 'alternative' fuels - Who is driving climate change policy?,Anti-coal and some investment policies are widely justified with reference to global warming| Political analysis suggests that these policies are supported by the reinforcing interests of three powerful lobbies: scientific institutions engaged in atmospheric research and earth observation| energy corporations harmed by low fossil fuel prices or supplying 'clean' technologies| and numerous interlocking bureaucracies| Together they have succeeded in maintaining momentum in current climate negotiations| The scientific consensus which underpins the climate treaty is examined critically| It is argued that support for emission abatement policies is better explained with reference to diplomatic interest in the globalisation of energy related investments and trade than understood causality between average global surface warming and fossil fuel combustion. (C) 1997 Published by Elsevier Science Ltd. All rights reserved. 4885,1997,3,2,Absorption chillers: Technology for the future,In an era of heightened awareness of energy efficiency and the associated environmental impacts| many industries worldwide are exploring "environmentally friendly" technologies that provide equivalent or improved performance while reducing or eliminating harmful side-effects. The refrigeration and air-conditioning industry| due to its reliance on CFCs and HCFCs| has invested in research in alternatives to the industry standard vapor compression machines. One alternative technology with great promise is chemical absorption. Absorption chiller; offer comparable refrigeration output with reduced SO2 CO2| and NOX emissions. Absorption chillers do not use CFCs or HCFCs| refrigerants that contribute to ozone depletion and global warming. Additionally| gas-fired absorption chillers can save significant amounts in energy costs when used in combination with a vapor compression chiller in a hybrid system. The hybrid system can take advantage of the comparatively low price of natural gas (per unit ton) and rely on the high performance of vapor compression when electricity prices are lower. The purpose of this article is to provide an introduction for those new to absorption technology as well as a discussion of selected high efficiency cycles| a discussion on the technology of coupling absorption with vapor compression systems to form a hybrid system| and the environmental impacts of absorption. 4700,1997,3,4,Absorption dynamics of CO2 bubbles in a pressurized liquid flowing downward and its simulation in seawater,The absorption process of carbon dioxide from a single bubble to the surrounding liquid at elevated pressure is studied both experimentally and theoretically. Experiments are conducted in a laboratory-scale column through which the liquid flows downward to hold each injected bubble nearly stationary. The system is pressurized up to 0.6 MPa and sodium chloride is added to water. A simple theoretical model is used to simulate the basic features of the absorption dynamics for bubbles ascending in shallow ocean. The bubble size is found to initially decrease almost linearly with time. The addition of NaCl significantly reduces the absorption rate of CO2. An analysis of shape or surface oscillations of the bubble reveals that this effect arises from the suppression of wavy fluctuations along the gas-liquid interface. The model predicts that the rate of bubble size reduction is almost independent of time and pressure for bubbles larger than 1 mm| reproducing the experimental results reasonably well. (C) 1997 Elsevier Science Ltd. 4798,1997,4,4,Acoustic effects of the ATOC signal (15 Hz| 195 dB) on dolphins and whales,The Acoustic Thermometry of Ocean Climate (ATOC) program of Scripps Institution of Oceanography and the Applied Physics Laboratory| University of Washington| will broadcast a low-frequency 75-Hz phase modulated acoustic signal over ocean basins in order to study ocean temperatures on a global scale and examine the effects of global warming. One of the major concerns is the possible effect of the ATOC signal on marine life| especially on dolphins and whales. Zn order to address this issue| the hearing sensitivity of a false killer whale (Pseudorca crassidens) and a Risso's dolphin (Grampus griseus) to the ATOC sound was measured behaviorally. A staircase procedure with the signal levels being changed in l-dB steps was used to measure the animals' threshold to the actual ATOC coded signal. The results indicate that small odontocetes such as the Pseudorca and Grampus swimming directly above the ATOC source will not hear the signal unless they dive to a depth of approximately 400 m. A sound propagation analysis suggests that the sound-pressure level at ranges greater than 0.5 km will be less than 130 dB for depths down to about 500 m. Several species of baleen whales produce sounds much greater than 170-180 dB. With the ATOC source on the axis of the deep sound channel (greater than 800 m)| the ATOC signal will probably have minimal physical and physiological effects on cetaceans. (C) 1997 Acoustical Society of America. 4856,1997,3,4,Advances in cyclomer technology for thermoplastic composites manufacture,The field of composites is experiencing a slight decrease in growth because of the end of the cold war| the associated decrease in defense research and development spending| and the sensitivity to impact fracture damage of commercial thermoset composites. Adaptation of the prior composites technology to a new generation of vehicles and commercial high-speed civil transports is growing steadily because of industry's need for low-cost| lightweight materials that allow improved fuel economy that in turn| reduces CO2 vehicle emissions and environmental (global warming) hazards. The use of the so-called 'cyclomer technology' for thermoplastic composites manufacture offers flexibility and many exciting opportunities that are briefly discussed in this review article. Because of the combination of the relative toughness of the thermoplastic matrices| the load-bearing ability of the continuous fibers and low processing costs| this new class of thermoplastic composites is expected to find increasing use in vehicular applications. 4860,1997,4,4,Agricultural C cycle and greenhouse gas emission in China,This paper assesses the production| consumption and store of organic carbon in the agricultural system| including all products from agriculture| of China. An estimation showed that about 90% of carbon uptake by agricultural systems would be emitted or returned to the atmosphere by several types from 1990 to 2000| others remain in durable agricultural products and soil. Even though the fixation rate is getting lower| generally speaking Chinese agriculture is a ''sink'' but not a ''source'' in respect to the atmospheric CO2 and CH4 concentrations in both the current period and that after few decades. China's Soil stores 12% of the whole soil carbon in the World. Considering the different global warming potentials (GWP)| an approach to the country budgets of CO2 and CH4 has been presented based on the measurements in rice paddies and in the Tibet and Inner Mongolia grasslands. 4883,1997,2,4,An evaluation of climate/mortality relationships in large US cities and the possible impacts of a climate change,A new air mass-based synoptic procedure is used to evaluate climate/mortality relationships as they presently exist and to estimate how a predicted global warming might alter these values. Forty-four large U.S. cities with metropolitan areas exceeding 1 million in population are analyzed. Sharp increases in mortality are noted in summer for most cities in the East and Midwest when two particular air masses are present ii very warm air mass of maritime origin is most important in the eastern United States| which when present can increase daily mortality by as many as 30 deaths in large cities. A hot| dry ait mass is important in many cities| and| although rare in the East| can increase daily mortality by up to 50 deaths. Cities in the South and Southwest show lesser weather/mortality relationships in summer. During winter| air mass-induced increases in mortality are considerably less than in summer. Although daily winter morality is usually higher than summer| the causes of death that are responsible for most winter mortality do not vary much with temperature. Using models that estimate climate change for the years 2020 and 2050| it is estimated that summer mortality will increase dramatically and winter mortality will decrease slightly| even if people acclimatize to the increased warmth. Thus| a sizable net increase in weather-related mortality is estimated if the climate warms as the models predict. 4868,1997,3,2,Anaerobic decomposition of organic carbon in paddy soil in relation to methane emission to the atmosphere,Paddy fields are regarded as one of the most important sources of methane emission which is enhancing global warming. To estimate decomposition processes of organic carbon in paddy soil quantitatively| firstly| kinetics of anaerobic decomposition of soil organic carbon (C) were investigated in laboratory experiments with or without organic amendments at 5| 20| 30 and 40 degrees C for 84 days of incubation. Produced CH4| CO2 and accumulated fatty acids were measured periodically| and first-order kinetics models were applied to the amount of decomposed C. Two components' model fitted decomposition pattern for unamended soil| but not for glucose or alanine-amended soils. To compare the parameters included in the model with those of adjacent upland soil| paddy soil contained smaller but faster components of decomposable organic matter. Secondly| methane emission from paddy soil was examined in paddy soil microcosms to find the possible mitigation options for reduction of the emission. Ammonium sulfate and potassium sulfate (S) were applied to compare with ammonium chloride and potassium chloride(C). Additionally ferrous oxide (F) was also applied to half sets of each treatment to make totally four treatments. Methane emission rate was significantly reduced by addition of S| much more effective than addition of F. Gas formation in the soil corresponded with the amendments| and the ratio of produced CH4 to CO2 decreased by addition of S at peak time of methane emission. (C) 1997 IAWQ. Published by Elsevier Science Ltd. 4825,1997,2,4,Analysis of merged SMMR-SSMI time series of Arctic and Antarctic sea ice parameters 1978-1995,The most consistent means of investigating the global sea ice cover is by satellite passive microwave sensors| as these are independent of illumination and cloud cover. The Nimbus 7 Scanning Multichannel. Microwave Radiometer (SMMR) and the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSMI) provide information on the global sea ice cover from 1978 to present. The two instruments flew simultaneously during a 6-week overlap period in July and August 1987| thus enabling intercomparison of the two sensors. Brightness temperatures are corrected for instrument drift and calibration differences in order to produce continuous time series of monthly averaged Arctic and Antarctic sea ice extent and sea ice area through the use of the NOr-wegian Remote Sensing EXperiment (NORSEX) algorithm| which relates brightness temperatures to ice concentration. Statistical analysis on the time series estimates the decreases in Arctic ice extent and ice area to be 4.5% and 5.7%| respectively| during the 16.8-year observation period. The overall trends established here serve to better define and strengthen earlier assertions of a reduced ice cover| based on analysis of SMMR and SSMI data taken separately. These results are consistent with GCM simulations that suggest retreat of the sea ice cover under global warming scenarios. 4834,1997,4,3,Arrhenius' 1896 model of the greenhouse effect in context,Arrhenius' 1896 model of the influence of carbonic acid (CO2) in the air on the temperature on the ground arose from debates concerning the causes of the Ice Ages in the Stockholm Physics Society. The calculation of the absorption-coefficients of H2O and CO2| which were the key to the construction of the model| was made possible through Arrhenius's use of Samuel P. Langley's measurements of heat emission in the lunar spectrum. The model enabled Arrhenius to show variations in mean temperature in sectors from 70 degrees N to 60 degrees S during four different seasons given five different levels of CO2. The immediate reactions to the model concerned the question which Arrhenius had attempted to answer| i.e.| the causes of the Ice Ages. Since the 1970s Arrhenius's work has received much wider attention due to the concern with global warming resulting from the burning of fossil fuels. 4701,1997,2,4,Aspects of carbon and nitrogen cycling in soils of the Bornhoved lake district .2. Modelling the influence of temperature increase on soil respiration and organic carbon content in arable soils under different managements,Based on field measurements in two agricultural ecosystems| soil respiration and long-term response of soil organic carbon content (SOC) was modelled. The model predicts the influence of temperature increase as well as the effects of land-use over a period of thirty years in a northern German glacial moraine landscape. One of the fields carried a maize monoculture treated with cattle slurry in addition to mineral fertilizer (''maize monoculture'')| the other was managed by crop rotation and received organic manure (''crop rotation''). The soils of both fields were classified as cambic Arenosols. The soil respiration was measured in the fields by means of the open dynamic inverted-box method and an infrared gas analyser. The mean annual soil respiration rates were 268 (maize monoculture) and 287 mg CO2 m(-2) h(-1) (crop rotation). Factors controlling soil respiration were soil temperature| soil moisture| root respiration and carbon input into the soil. Q(10)-values of soil respiration were generally higher in winter than in summer. This trend is interpreted as an adaptive response of the soil microbial communities. In the model a novel mathematical approach with variable Q(10)-values as a result of temperature and moisture adjustment is proposed. With the calibrated model soil respiration and SOC were calculated for both fields and simulations over a period of thirty years were established. Simulations were based on (1) local climatic data| 1961 until 1990| and (2) a regional climate scenario for northern Germany with an average temperature increase of 2.1 K. Over the thirty years period with present climate conditions| the SOC pool under ''crop rotation'' was nearly stable due to the higher carbon inputs| whereas about 16 t C ha(-1) were lost under ''maize monoculture''. Under global warming the mean annual soil respiration for both fields increased and SOC decreased by ca. 10 t C ha(-1) under ''crop rotation'' and by more than 20 t C ha(-1) under ''maize monoculture''. It was shown that overestimation of carbon losses in long-term prognoses can be avoided by including a Q(10)-adjustment in soil respiration models. 2457,1997,3,4,Assessing effects of mitigation strategies for global climate change with an intertemporal model of the US forest and agriculture sectors,A model of product and land markets in U.S. forest and agricultural sectors is used to examine the private forest management| land use| and market implications of carbon sequestration policies implemented in a "least social cost" fashion. Results suggest: policy-induced land use changes may generate compensating land use shifts through markets; land use shifts to meet policy targets need not be permanent; implementation of land use and management changes in a smooth or regular fashion over time may not be optimal; land use changes account for the largest part of adjustments to meet policy targets; and forest management changes involve higher intensity and less forest type conversion. 2430,1997,4,3,Assessing the DICE model: Uncertainty associated with the emission and retention of greenhouse gases,Analysis of the DICE model indicates that it contains unsupported assumptions| simple extrapolations| and misspecifications that cause it to understate the rate at which economic activity emits greenhouse gases and the rate at which the atmosphere retains greenhouse gases| The model assumes a world population that is 2 billion people lower than the 'base case' projected by demographers. The model extrapolates a decline in the quantity of greenhouse gases emitted per unit of economic activity that is possible only if there is a structural break in the economic and engineering factors that have determined this ratio over the last century| The model uses a single equation to simulate the rate at which greenhouse gases accumulate in the atmosphere| The forecast for the airborne fraction generated by this equation contradicts forecasts generated by models that represent the physical and chemical processes which determine the movement of carbon from the atmosphere to the ocean. When these unsupported assumptions| simple extrapolations| and misspecifications are remedied with simple fixes| the economic impact of global climate change increases several fold. Similarly| these remedies increase the impact of uncertainty on estimates for the economic impact of global climate change. Together| these results indicate that considerable scientific and economic research is needed before the threat of climate change can be dismissed with any degree of certainty. 2379,1997,2,4,Assessment of current and future regional climate scenarios for Mexico,Current climate and climate change scenarios are the basis for climate change vulnerability and adaptation studies. Comparison between the current situation and the one that would prevail under climate change conditions allows for the identification of vulnerable regions and the quantification of vulnerability. This may be done by evaluating the land area adversely affected by climate change (e.g. with reduction in agricultural yields or decrease in the level of water reservoirs). Specific regionalization criteria and methods based on physical considerations should be applied in the development of regional climate scenarios. This is the principle followed in studies using analogue scenarios. A methodology based on the direct interpolation of general circulation model (GCM) outputs to the study region under 1xCO(2) and 2xCO(2) conditions may be used as a first approach for the development of climate change scenarios. That methodology was applied in this study in order to be consistent with the assessments performed by more than 50 countries involved in the U.S. Country Studies Program and to allow for the comparison and integration of the results from several countries. However| an alternative methodology based on multiple regression was also applied by the Scenario task group of the Mexico Country Study. This methodology is considered to be more appropriate for regionalization purposes. 2448,1997,2,1,Assessments of the global anthropogenic greenhouse and sulfate signal using different types of simplified climate models,The problem of global climate change forced by anthropogenic emissions of greenhouse gases (GHG) and sulfur components (SU) has to be addressed by different methods| including the consideration of concurrent forcing mechanisms isms and the analysis of observations. This is due to the shortcoming and uncertainties of all methods| even in case of the most sophisticated ones. III respect to the global mean surface air temperature| we compare the results from multiple observational statistical models such as multiple regression (MRM) and neural networks (NNM) with those of energy balance (EBM) and general circulation models (GCM) where| in the latter case| we refer to the recent IPCC Report. Our statistical assessments| based on the 1866-1994 period| lead to a GHG signal of 0.8-1.3 K and a combined GHG-SU signal of 0.5-0.8 K detectable in observations. This is close to GCM simulations and clearly larger than the volcanic| solar and ENSO (El Nino/southern oscillation) signals also considered. 4739,1997,3,2,Atmospheric issues in Canada,Six atmospheric 'issues' are currently being assessed by scientists| modellers and policy analysts in Canada: climate change; stratospheric ozone depletion (including W-B radiation increases); acidic deposition; smog (e.g. ground-level ozone episodes); suspended particulate matter; and hazardous air pollutants. This paper provides a brief historical review of how these particular issues came to the forefront internationally and in Canada. Then the characteristics of the issues are described| revealing the wide range of space and time scales involved| as well as the several different ecological systems and socioeconomic sectors affected. Historically each air issue has been treated as a separate problem - from root causes| through the atmospheric processes involved| through the impacts on the biosphere and society| and finally to the design of policies to slow down or eliminate unwanted impacts. In recent years| however| recognition has been growing that the six air issues are interrelated through complex feedbacks| lags and synergisms. For example| replacing CFCs may slow down stratospheric ozone depletion| but the replacement gases may contribute to climate warming. The lesson to be learned by both scientists and policy analysts is therefore that strategies for dealing with a particular issue may not be optimal for the whole. Two examples are given to illustrate the paint. (1) With respect to policies to reduce greenhouse gas emissions| the warming potentials of all such gases should be assessed| and the effects of proposed strategies on the other five air issues should also be included. (2) With respect to regional land-use planning| a long-term perspective (decades) should be taken| and the effects of global and regional atmospheric change on the region should be included in the assessment. Because the future is difficult and often impossible to predict| an adaptive strategy is recommended in which options are kept open| and the assessment document is revisited periodically (at 2-5-year intervals). (C) 1997 Elsevier Science B.V. 4893,1997,3,3,Atmospheric methane: Sources| sinks| and strategies for reducing agricultural emissions,Methane (CH4) is one of the most abundant organic gases in the atmosphere. Recently the importance of CH4 as a greenhouse gas has been recognized and studies have been carried out to asses its contribution to global warming. In this paper we show that atmospheric CH4 is produced by a wide variety of natural and anthropogenic processes. Then| we discuss mainly production| consumption and emission of CH4 in paddy fields. Finally| we provide an estimate of the mitigation potential in agricultural systems including rice production| ruminant animals and animal waste. (C) 1997 IAWQ. Published by Elsevier Science Ltd. 4707,1997,3,2,Austrian agriculture's share in the emission of trace gases affecting the climate,Agriculture's share including all direct and indirect processes such as clearing of forests in the tropics in anthropogenic global warming potential is about more than 30%. When the inappropriate cultivation methods and land use changes in the tropic and subtropic areas| which cause especially high CO2-emissions| are excluded agriculture's share is about 13%| now methane emissions (from livestock husbandry and rice paddies) and nitrous oxide emissions (due to nitrogen inputs to the soils) are predominating. In Austria agriculture's share in national warming potential is about 10%. If only emissions in direct connection with agricultural land use (incl. fuel consumption| use of mineral and organic N-fertilizers and use of plant protective agents| but excl. emissions from livestock husbandry and from use of electricity power| gas and fuel oil for heating) are included agriculture's share is about 5%. In the past specialization in agricultural production resulting in unbalanced crop rotations and intensification of soil cultivation might have contributed to degradation of organic carbon on arable land. However| topsoils are still an important carbon reservoir| which must be preserved by competent and sustainable soil cultivation (well balanced crop rotation|planting of cover crops| incorporation of crop residues in the soil). Agriculture may contribute a relevant amount to reduce emissions of climate affecting trace gases when the potential for biomass production is used. Extensification strategies in all fields of plant production should be further optimised for preserving natural resources and using energy inputs efficiently. 4857,1997,4,4,Bayesian methods for analysing climate change and water resource uncertainties,The purpose of this paper is to outline the advantages of the Bayesian approach for analysing uncertainties involving climate change| emphasizing the study of the risks such changes pose to water resources systems. Bayesian analysis has the advantage of basing inference and decisions on a coherent and normatively appealing theoretical framework. Furthermore| it can incorporate diverse sources of information| including subjective opinions| historical observations and model outputs. The paper summarizes the basic assumptions and procedures of Bayesian analysis. Summaries of applications to detection of climate change| estimation of climate model parameters| and wetlands management under climatic uncertainty illustrate the potential of the Bayesian methodology. Criticisms of the approach are summarized. It is concluded that in comparison with alternative paradigms for analysing uncertainty| such as fuzzy sets and Dempster-Shafer reasoning| Bayesian analysis is practical| theoretically sound| and relatively easy to understand. (C) 1997 Academic Press Limited 4809,1997,2,4,Between-year variation in climate-related growth of circumarctic populations of the moss Hylocomium splendens,1. The correlation between climatic variables and past (up to 20 years) growth was studied in seven circumarctic populations of the moss Hylocomium splendens| using retrospective analyses of growth. We hypothesized that relationships between growth and climate would be simpler in an ectohydric moss than in higher plants and that the moss could provide high signal-to-noise ratios of responses to climatic variation. 2. Growth parameters of the moss were strongly correlated with early summer temperatures and with the length of the growing season. Annual segment mass| growth rates and degeneration rates were highest at the mildest subarctic sites and lowest at the high arctic site. In contrast| 'longevity' (age of the oldest segment) increased at the climatically harsher sites. 3. Between-year growth variations at two contrasting sites were significantly correlated with June and July temperatures and| to a lesser extent| with early-season precipitation at one of the sites. 4. The moss currently tolerates a wide range of climates and large interannual variations in temperature and is likely to be at risk from climatic change only at the southern edge of its range. 5. The climate-change component most likely to affect the growth of H. splendens in the Arctic and Subarctic will be a lengthening of the growing season and in increase in early summer temperatures provided that moisture is not limiting. 6. Hylocomium splendens is a suitable species for monitoring climatic change at a circumarctic scale. 2452,1997,3,2,Biological fossil CO2 mitigation,Over ten times more CO2 is fixed by plants into biomass| and annually released by decomposers and food chains| than is emitted to the atmosphere due to the burning of fossil fuels. Human activity is already directly and indirectly affecting almost half of the terrestrial biological C cycle. Management of even a small fraction of the biological C cycle would make a major contribution to mitigation of this greenhouse gas. Electric power generation is responsible for roughly one third of fossil CO2 emissions. Direct CO2 mitigation processes are those that reduce fossil CO2 emissions from specific power plants. Direct biological CO2 mitigation processes include the cultivation of microalgae on flue-gas or captured CO2| and the cofiring of wood with fossil fuels. Indirect biological processes| such as growing trees for C storage or for fueling dedicated biomass power plants| recapture CO2 that already has entered the atmosphere. Indirect and direct CO2 mitigation processes have the same overall effect in reducing global warming potential. Reducing global CO2 emissions from forest destruction and unsustainable agricultural and land use practices is one of the most cost-effective| and environmentally beneficial actions that can be taken now to arrest global climate change. Another near-term option is to enhance the substitution of fossil fuels with biofuels. Biofuels are a major source of fuel for the poorer half of mankind. Globally| biofuels could replace a substantial fraction of current fossil fuel usage. Cofiring biomass wastes and residues with coal is one of the lowest-cost| nearest-term options for reducing fossil CO2 emissions at existing power plants. Long-term demonstrations of biomass cofiring are required at full-scale coal-fired power plants to document efficiencies| ash characteristics| biomass preparation and feeding| and other technical issues. Biomass fuel resources for cofiring can be expanded in the near-term through greater recovery of wastes and residues in forestry and agriculture| and in the mid-term through systems that produce biomass specifically for use as fuels (energy crops). (C) 1997 Elsevier Science Ltd. 4839,1997,2,4,Bleaching of the coral Oculina patagonica by Vibrio AK-1,Bleaching in stony corals is the result of a disruption of the symbiosis between the coral hosts and photosynthetic microalgal endosymbionts (zooxanthellae). Coral bleaching may be induced by a variety of environmental stimuli| including increased seawater temperature. Large-scale bleaching episodes have been suggested to be linked to global warming. We have discovered that coral bleaching| in this case| bleaching of the Mediterranean coral Oculina patagonica| is caused by a bacterid infection and that water temperature is a contributing factor. The causative agent| Vibrio AK-1| was present in 28 bleached O. patagonica examined| but absent from 24 healthy (unbleached) corals. The Vibrio sp. was isolated in pure culture| characterized microbiologically| and shown to cause bleaching when inoculated onto unbleached corals. An increase in seawater temperature may influence the outcome of bacterial infection by lowering the resistance of the coral to infection and/or increasing the virulence of the bacterium. When inoculated with 10(6) Vibrio AK-1 ml(-1) at 26 degrees C| bleaching began at around 10 d and affected more than 80% of the corals after 44 d. Bleaching did not occur under the same conditions in the presence of antibiotics or if the temperature was lowered to 16 degrees C. 4811,1997,4,4,Borehole temperatures and a baseline for 20th-century global warming estimates,Lack of a 19th-century baseline temperature against which 20th-century warming can be referenced constitutes a deficiency in understanding recent climate change. Combination of borehole temperature profiles| which contain a memory of surface temperature changes in previous centuries| with the meteorological archive of surface air temperatures can provide a 19th-century baseline temperature tied to the current observational record. A test case in Utah| where boreholes are interspersed with meteorological stations belonging to the Historical Climatological Network| yields a noise reduction in estimates of 20th-century warming and a baseline temperature that is 0.6 degrees +/- 0.1 degrees C below the 1951 to 1970 mean temperature for the region. 4742,1997,4,6,Can increasing carbon dioxide cause climate change?,The realistic physical functioning of the greenhouse effect is reviewed| and the role of dynamic transport and water vapor is identified| Model errors and uncertainties are quantitatively compared with the forcing due to doubling CO2| and they are shown to be too large for reliable model evaluations of climate sensitivities| The possibility of directly measuring climate sensitivity is reviewed. A direct approach using satellite data to relate changes in globally averaged radiative flux changes at the top of the atmosphere to naturally occurring changes in global mean temperature is described| Indirect approaches to evaluating climate sensitivity involving the response to volcanic eruptions and Eocene climate change are also described. Finally| it is explained how| in principle| a climate that is insensitive to gross radiative forcing as produced by doubling CO2 might still be able to undergo major changes of the sort associated with ice ages and equable climates. 4820,1997,2,4,Carbon balance of tundra landscape in Central Siberia: Observations| simulation and GIS-modelling,Comprehensive statistical analysis of field measurements of CO2 fluxes in ecosystems of typical subarctic tundra in Taymir Peninsula (Central Siberia| Russia) was performed. Simulation models allowing to compute integrate seasonal values of basic components of carbon balance in the most characteristic plant communities of typical tundra were built. To access the landscape pattern of tundra carbon balance we applied GIS-approach based on the original computer map of ecosystem borders. In 1994 the seasonal (from the beginning of snow melting till the end of total soil freezing) carbon balance of typical tundra landscape was estimated as -4 g C . m-(2) . year(-1) (carbon sink)| the ecosystem total respiration as +145 g C . m(-2) . year(-1)| and gross primary production as -149 g C . m(-2) year(-1). Such a poorly expressed carbon sink conceptually should be considered as landscape equilibrium. Nevertheless the subsequent computer simulation of climate changes confirmed the hypothesis of positive feedback between global warming and change of carbon balance pattern in tundra ecosystems from sink to source. From the other side we found that regional peculiarities of ecological and climatic conditions can strongly effect the climate global change appearance. 2458,1997,3,4,Carbon dioxide-enriched agroecosystems: Influence of tillage on short-term soil carbon dioxide efflux,Increasing atmospheric carbon dioxide (CO2) concentration can increase biomass production that may influence carbon (C) dynamics in terrestrial ecosystems. Soil CO2 efflux as affected by crop residues from high CO2 environments managed under different tillage systems has not been explored. This study examined the effects of tillage systems in a legume \{soybean [Glycine max (L.) Merr.]\} and nonlegume \{grain sorghum [Sorghum bicolor] (L.) Moench.\} CO2-enriched agroecosystem on the rates of short-term CO2 evolution from a Blanton loamy sand (loamy siliceous| thermic Grossarenic Paleudults). In the spring of 1993| CO2 efflux observations initiated within 5 s after a tillage event were compared to no-tillage conditions for 8 d in plots where both crop species had been grown in open top field chambers under two CO2 conditions (ambient and twice ambient) for two seasons (1992 and 1993). Added CO2 increased yields| residue| and root biomass; higher percent ground cover was also observed in CO2-enriched plots prior to the tillage treatment. Differences in C/N ratio of the residue may have influenced CO2 efflux rates; C/N ratio was highest for sorghum and was increased by elevated CO2. Efflux patterns were characterized by flushes of CO2 following initial tillage and rainfall events. Species x tillage and CO2 x species interactions were noted on several days and for total CO2 efflux values. Our results suggest that short-term CO2 fluxes may be greater for tilled soybean and for soybean grown under elevated CO2; however| short-term flux rates in the sorghum crop were affected by tillage| but not by CO2 level. These short-term results should be viewed with caution when predicting long-term C turnover in agroecosystems. 4796,1997,4,4,Carbon pool dynamics in the Lower Fraser Basin from 1827 to 1990,To understand the total impact of humans on the carbon cycle| the modeling and quantifying of the transfer of carbon from terrestrial pools to the atmosphere is becoming more critical. Using previously published data| this research sought to assess the change in carbon pools caused by humans in the Lower Fraser Basin (LFB) in British Columbia| Canada| since 1827 and define the long-term| regional contribution of carbon to the atmosphere. The results indicate that. there has been a transfer of 270 Mt of carbon from biomass pools in the LFB to other pools| primarily the atmosphere. The major losses of biomass carbon have been from logged forests (42%)| wetlands (14%)| and soils (43%). Approximately 48% of the forest biomass| almost 20% of the carbon of the LFB| lies within old-growth forest| which covers only 19% of the study area. landfills are now becoming a major sink of carbon| containing 5% of the biomass carbon in the LFB| while biomass carbon in buildings| urban vegetation| mammals| and agriculture is negligible. Approximately 26% of logged forest biomass would still be in a terrestrial biomass pool| leaving 238 Mt of carbon that has been released to the atmosphere. On an area basis| this is 29 times the average global emissions of carbon| providing an indication of the past contributions of developed countries such as Canada to global warming and possible contributions from further clearing of rainforest in both tropical and temperate regions. 4859,1997,2,4,Carbon storage along a latitudinal transect in Alaska,Global warming is anticipated to have a significant impact on high-latitude ecosystems which store large amounts of C in their soils and have a predominance of permafrost. The purpose of this study was to estimate the total C storage of different ecosystems along a north-south transect in Alaska. Soil pedons from three Alaska climate zones were studied. These zones were the arctic slope with continuous permafrost and vegetation predominantly tussock tundra and coastal marsh| Interior Alaska with discontinuous permafrost and vegetation predominantly spruce forest on the upland and tundra or bog in the lowland| and Southern Alaska free of permafrost with the vegetation predominantly mixed hardwood and conifers with moss bogs. Soil samples were taken from the representative ecosystems of these zones for carbon storage analysis. In the Arctic and Interior Alaska zones| many soils are cryoturbated and as a result the horizons are warped and often broken. These conditions made it impractical to use the common method for estimating C storage that is used for soils with roughly parallel horizons. For this study the linear proportion of each horizon in the cryoturbated pedon was digitized by using a Geographic Information System (GIS) and the irregular horizons were collapsed to form a simulated profile with parallel horizons. The carbon content of each pedon was then calculated based on the linear proportions. These carbon stores based on the whole soil (1 m deep) approach were compared to other available estimates from the literature. Calculations for pedons from selected ecosystems in Alaska ranged from 169 MgC/ha to 1292 MgC/ha. The organic carbon storage of the arctic coastal marsh pedon amounted to 692 MgC/ha| and that of the arctic tundra pedon amounted to 314 and 599 MgC/ha. The carbon storage of interior forest pedons was 169 and 787 MgC/ha| and the associated organic soil stored nearly 1300 MgC/ha. The carbon storage in the mixed forest and coastal forest pedons was 240 and 437 MgC/ha| respectively. The bog associated with the mixed and coastal forest stored 1260 MgC/ha. Soils with the thickest organic layers were bogs associated with the tundra and boreal forest. These soils had the largest carbon storage. Carbon stores estimated from the whole pedon approach are 30 to 100% higher than those from the literature from the same zones. These data suggest that the global carbon storage estimates based in part on literature values from the N. latitudes| may be underestimated. 4875,1997,3,4,Cascading of pine wood,Resource-cascading| the sequential exploitation of the full potential of a resource during its use| is one of the ways to improve efficiency of raw materials use. In this article it is shown that cascading of the renewable resource pinewood can lead to large savings in primary resource use. For pine wood a cascade of five or six steps can be set up which extends the time that the resource is in use from about 75 to more than 350 years. Cascading also means that| when using wood| the moment that carbon dioxide is emitted| is postponed. This is interesting in relation to global warming. In the Netherlands| a country where labour is relatively expensive| parts of this cascade are realised in practice. Until now| however only a small percentage of the total amount of wood is cascaded. To favour cascading of wood several options may be considered| such as eco-taxation of resources| prohibition to dump waste-wood and a 'wood-bank' showing which kind of wood with certain properties is available at a certain moment. Copyright (C) 1997 Elsevier Science B.V. 4744,1997,3,4,Cascading of renewable resources hemp and reed,Resource-cascading| the sequential exploitation of the full potential of a resource during its use| is one of the ways to improve efficiency of raw materials use. To design a good cascade knowledge of the typical properties and structures of the plant is useful. In this article it is shown that cascading of the renewable resources hemp and reed can lead to large savings in primary resource use. Resource cascading can therefore make the option to replace non-renewable resources by renewables more realistic. In comparison with using biomass (e.g. reed| hemp| straw) for energy directly| cascading also means that| carbondioxide emission| is postponed. This is interesting in relation to global warming. (C) 1997 Elsevier Science B.V. 2424,1997,2,4,Change in avian abundance across the geographic range in response to environmental change,The abundance changes of three North American passerine bird species after the harsh winters of the late 1970s were analyzed to determine relationships between proportional abundance change and prewinter abundance| position within the geographic range| and winter severity| Analyses were made between both the prewinter period and a period of declining abundance immediately after the winters and between this decline period and a later period of recovery in which abundance increased. The proportional declines in abundance showed no relationship to prewinter abundances. Proportional abundance change was greatest at sites closer to the range edge and| for two species| at sites with a more severe winter. Proportional abundance increases of these two species between the decline and recovery periods similarly were greatest at sites near the range edges and with previously more severe winters. Abundance increases were|oreater at sites with the lowest predecline abundance. Geographic range structures showed changes parallel to the abundance changes| including overall contraction and expansion. In addition| there was evidence of fine-scale range dynamics| including extinction and colonization events toward the range margins and a roughening of the range boundary with abundance decrease followed by a smoothing of the boundary with abundance increase| Periods of major environmental change| such as these severe winters| may provide insight into how populations of organisms will respond to global climate change. In particular| this study suggests that population declines will be accompanied by a contraction toward core areas of the range that formerly had the highest abundance| However| more investigation is clearly needed into the precise nature of broad-scale population dynamics following environmental perturbations that cause abundance change. 4706,1997,5,3,Changes in accumulation rate of organic carbon during the last 8|000 years in sediments of Nakaumi Lagoon| Japan,Changes in the organic carbon accumulation rate (C-org A.R.) and their relation to climate changes during the last 8|000 years were investigated in a 20 m sediment core from the Nakaumi Lagoon| southwest Japan. High-resolution C-14 dating was possible from fifteen shell samples. The warm climate interval 8|000-6|500 cal. yr B.P. was accompanied by increase in the C-org A.R. (21-32 g m(-2) yr(-1)) and the cool climate interval 3.000-2|000 cal. yr B.P. by a decrease (11 g m(-2) yr(-1)). The accumulation of both terrestrial and planktonic organic matter increased during the warm interval. The lagoon seems to act as a more effective small sink for atmospheric CO2 following the global warming climate. (C) 1997 Elsevier Science B.V. 4781,1997,2,4,Changes in water relations for leaves exposed to a climate-warming manipulation in the Rocky Mountains of Colorado,Relative water content (RWC) and water potential were compared for leaves of several plant species exposed to a warming manipulation at the Rocky Mountain Biological Laboratory| near Crested Butte| Colorado| USA| to test the hypothesis that species-specific changes in water relations parameters will occur in response to future increases in planetary air temperatures. Leaves of Artemisia tridentata| Erigeron speciosus| Festuca thurberi| Helianthella quinquinervis| Potentilla fruticosa| Potentilla gracilis and Rhodiola integrifolia were collected from plants growing in situ in control and infrared (IR)-heated (22 W m(-2)) plots in a meadow near the upper elevational distribution limit for A. tridentata. For six of the seven herbaceous species| RWC was not significantly different from that for A. tridentata (0.903+/-0.019 on control plots and 0.846+/-0.031 from heated plots). However| RWC was 0.644+/-0.04 and 0.596+/-0.029 for F. thurberi on control and heated plots| respectively. Water potential (Psi) varied from -1.04 MPa for A. tridentata (control plots) to -4.83 MPa for leaves of F. thurberi (heated plots); Psi for the other species ranged from -1.08 MPa (R. integrifolia on control plots) to -2.62 MPa (P. gracilis on heated plots). To characterize further the responses of water relations parameters to the IR heating treatment| pressure-volume isotherms were generated for A. tridentata and P. gracilis. Both species exhibited effects of the IR heating treatment on saturated osmotic potential and the relative symplastic water content. Based on changes in osmotic potential and relative water content| an increase in osmotically active solutes was exhibited for leaves collected from plants under heaters. Species-specific patterns of RWC and water potential (as well as effects on cellular water relations) may influence the ability of plant species to cope with changes in soil water content that are expected to occur with global warming for montane ecosystems in the western USA. (C) 1997 Elsevier Science B.V. 4774,1997,3,4,Characteristics of a CO2-recovering combined cycle power generation system when its CO2 recovery rate is changed,This study investigated how the net power generation efficiency varied when its CO2 recovery rate was raised| by taking a combined cycle power generation system as an example. In the system| alkanolamine-based chemical solvent was assumed to be used to remove and recover CO2 from the stack gas| and the extracted steam from the steam turbine at a temperature of 454 K to regenerate CO2-absorbed solvent. The equation to estimate the net power generation efficiency eta(N) was derived when its CO2 recovery rate R-CO2 is changed| and a simulation model was developed to estimate various characteristics of the system. It has been estimated that eta(N) is 50.2% when R-CO2 is 0%| but the value of eta(N) degrades sharply according to the rise of the value of R-CO2| and eta(N) decreased to 37.7% when R-CO2 is raised to 90%; that is| the efficiency of the system becomes lower than 37.7%| that of a CO2-recovering steam turbine generation system using the same chemical CO2 absorption solvent. (C) 1997 by John Wiley gr Sons| Ltd. 4752,1997,4,3,Climate change and the insurance industry: the cost of increased risk and the impetus for action,A convincing economic argument for taking action to prevent or ameliorate climate change has not developed because of both uncertainty about the degree of change and its timing. Recent costly weather-related catastrophes with consequent negative impacts on the insurance industry has made the insurance industry a potential advocate for slowing what has been identified as a causal factor in climate change: emissions of greenhouse gases. However| rising costs of claims| without a longer-term trend of such catastrophic losses| will make it difficult to present a strong case for taking costly economic action. Using the Black Scholes Option Pricing Model| it is shown that increasing levels of climate variability as embedded in the anticipated variability of damage to insured assets will have an immediate economic cost that could serve to bolster the argument for more immediate action. That cost is shown to be economically justified higher insurance premiums. (C) 1997 Elsevier Science B.V. 2408,1997,2,4,Climate change and water resources,Current perspectives on global climate change based on recent reports of the Intergovernmental Panel on Climate Change (IPCC) are presented. Impacts of a greenhouse warming that are likely to affect water planning and evaluation include changes in precipitation and runoff patterns| sea level rise| land use and population shifts following from these effects| and changes in water demands. Irrigation water demands are particularly sensitive to changes in precipitation| temperature| and carbon dioxide levels. Despite recent advances in climate change science| great uncertainty remains as to how and when climate will change and how these changes will affect the supply and demand for water at the river basin and watershed levels| which are of most interest to planners. To place the climate-induced uncertainties in perspective| the influence on the supply and demand for water of non-climate factors such as population| technology| economic conditions| social and political factors| and the values society places on alternative water uses are considered. 2425,1997,2,4,Climate change| agriculture and wetlands in Eastern Europe: Vulnerability| adaptation and policy,Naturally-occurring wetlands perform such functions as flood control| pollution filtration| nutrient recycling| sediment accretion| groundwater recharge and water supply| erosion control| and plant and wildlife preservation. A large concentration of wetlands is located in Eastern Europe. A significant amount of Eastern European wetlands has been converted to agricultural use in the past| and remaining wetlands are subject to agricultural drainage. Drained wetlands are used as prime agriculture lands for a variety of food crops. Other agricultural uses of wetlands range from growing Phragmites australis (common reed) for thatch and livestock feed| to collecting peat for heating and cooking fuel. Altered hydrologic regimes due to global climate change could further exacerbate encroachment of agricultural land use into wetlands. The vulnerability and adaptation studies of the U.S. Country Studies Program are used to analyze where climate change impacts to agriculture may likewise impact wetland;areas. Scenarios indicate higher temperatures and greater evapotranspiration altering the hydrologic regime such that freshwater wetlands are potentially vulnerable in Bulgaria| Czech Republic| and Russia| and that coastal wetlands are at risk in Estonia. Runoff is identified as a key hydrological parameter affecting wetland function. Since wetland losses may increase as a result of climate-change-induced impacts to agriculture| precautionary management options are reviewed| such as establishing buffer areas| promoting sustainable uses of wetlands| and restoration of farmed or mined wetland areas. These options may reduce the extent of negative agricultural impacts on wetlands due to global climate change. 4754,1997,2,3,Climate changes in the greater and southern Caribbean,A climate change resulting from recent increases in the atmospheric greenhouse gases (GHGs) is supposed to occur sometime in the middle of the next century. This climate change induced by GHGs would be caused by radiative forcing through the greenhouse effect and would lead to global warming and eventually to sea-level rise. This paper presents a climate change scenario for the greater Caribbean as simulated by the Canadian Climate Centre (CCC) general circulation model (GCM). The CCC GCM projects a GHG induced temperature increase of about 2 degrees C and more extreme rainfall conditions for the greater Caribbean. The climate records of temperature| rainfall and cloudiness for several stations on the island of Trinidad are then examined in an attempt to detect GHG climate change signals. The temperature change to date| close to 1 degrees C| and the fluctuations in rainfall patterns| over the last five decades| seem to be indicative of early greenhouse signals. (C) 1997 by the Royal Meteorological Society. 4763,1997,3,3,Climate convention implementation: An opportunity for the Pacific island nations to move toward sustainable energy systems,The impacts of global warming are among the more serious environmental threats far the Pacific Island countries. These nations justifiably argue that developed countries should give immediate priority to the implementation of climate change mitigation policies because of the severe nature of potential greenhouse impacts for the Pacific Islands. Another immediate priority acknowledged by these nations is the need for development of adaptation policies that plan for adjustment or adaptation| where possible| to the foreshadowed impacts of climate change. This article does not focus on adaptation or mitigation policy directly but on an allied opportunity that exists for the Pacific Islands via the auspices of the Climate Convention| because the existing very costly energy systems used in the Pacific island region are fossil-fuel dependent. It is argued here that efforts can be made towards the development of energy systems that are ecologically sustainable because Pacific Island nations are eligible to receive assistance to introduce renewable energy technology and pursue energy conservation via implementation mechanisms of the Climate Convention and| in particular through transfer of technology and via joint implementation. II is contended that assistance in the form of finance| technology| and human resource development from developed countries and international organizations would provide sustainable benefits in improving the local Pacific island environments. It is also emphasized that mitigation of greenhouse gas emissions is not the responsibility of the Pacific Islands as they contribute very little on a per capita global scale and a tiny proportion of total global greenhouse gas emissions. 4824,1997,4,2,Climate model studies of sulphate aerosols and clouds,It is generally believed that increases in the atmospheric concentrations of greenhouse gases as a result of man's activities are leading to global warming. It is also believed that the same activities lead to increasing concentrations of sulphate aerosol| which act to cool the climate system and ameliorate the warming. The sulphate cooling may be separated into the direct effect in cloud-free regions and the indirect effect in cloudy regions. This paper summarizes recent work at the Hadley Centre on the indirect effect. Results from two versions of the Hadley Centre Climate Model are shown| using various parameterizations linking the amount of sulphate aerosol and the number concentration of droplets in water clouds. These results illustrate the considerable uncertainties in estimating the indirect effect. It is shown that other naturally occurring components of the aerosol population| in particular sea salt| may be important in reducing the magnitude of the indirect effect. 4780,1997,4,3,Climate variability of a coupled ocean-atmosphere-land surface model: Implication for the detection of global warming - The Walter Orr Roberts lecture,This lecture evaluates the low-frequency variability of surface air temperature that was obtained from a 1000-yr integration of a coupled ocean-atmosphere-land surface model. The model simulates reasonably well the variability of local and global mean surface air temperature (SAT) at decadal timescales. The physical mechanisms responsible for this variability are explored. Based upon an analysis of the time series of the simulated global mean SAT| it is indicated that the warming trend of similar to 0.5 degrees C century(-1) since the end of the last century was not generated internally through the interaction among the atmosphere| ocean| and land surface. Instead| it appears to have been induced by a sustained change in the thermal forcing such as that resulting from changes in atmospheric greenhouse gas concentration| solar irradiance| and aerosol loading. 4713,1997,4,3,Climate-related global changes in the southern Caribbean: Trinidad and Tobago,A climate change deriving from the atmospheric build up of greenhouse gases (GHG) is supposed to become evident by the middle of the next century. This GHG-induced climate change would supposedly lead to a global warming of about 2 to 4 degrees C and a rise in mean sea level of about 60 cm towards the end of the next century. This study focuses on the field measurements and interpretations of a number of| supposedly| climate-driven regional changes| including shifts in climate and hydrology| coastal erosion and sedimentation| salinisation of coastal aquifers and estuaries| and also coral bleaching| in Trinidad and Tobago| in the southern Caribbean. The results show significant changes and shifts in temperature and rainfall| severe coastal erosion| approaching 2 to 4 m per year for certain beaches| appreciable salinisation of a number of coastal aquifers and an estuary along the Caroni swamp| in Trinidad| and what appears to be partial coral bleaching| at the Culloden Reef in Tobago. These field-observed regional changes may conceivably be interpreted as early signals of a GHG-induced climate change. However| in view of the uncertainty surrounding GHG-induced climate change and sea level rise and the limitations of our data| especially the length of record| caution must be exercised in the interpretation of these results. (C) 1997 Elsevier Science B.V. 4865,1997,3,4,CO2 mitigation with microalgae systems,Microalgae present one of the few technologies for the capture and utilization of CO2 emitted by power plants| These microscopic plants would be grown in large open ponds| into which power plant flue gas or pure CO2 (captured from power plants) is sparged| and| after harvesting| the biomass would be converted to a fossil fuel replacement| preferably a high value liquid fuel such as biodiesel. The requirements for large areas of land| favorable climate| and ample water supplies will restrict the potential of this technology. Also| even with rather favorable technical assumptions| the currently projected costs of microalgae-fuels are high| similar to most power plant CO2 capture and disposal options. However| if the technology of microalgae could achieve very high productivities| equivalent to 10% solar energy conversion| and if projected low-cost cultivation| harvesting and processing techniques could be developed| microalgae technology could become a low-cost CO2 mitigation option| particularly if prices for fossil fuels increase in the future. In the nearer-term microalgae CO2 utilization can be integrated with wastewater treatment and reclamation| providing an early application of this technology. Long-term basic and applied R&D are required to develop this technology| as one of the many options that may be required in the future to help preserve our planetary atmosphere and biosphere. (C) 1997 Elsevier Science Ltd. 4802,1997,2,4,Combined effects of night-time temperature and allelochemicals on performance of a generalist insect herbivore,To assess the pattern of temperature influencing the effect of allelochemicals on growth of insect herbivores and to examine the potential effect of warmer nights due to global warming| we examined the simultaneous effects of allelochemicals and warmer night-time temperatures on an insect herbivore (Spodoptera exigua; Lepidoptera: Noctuidae). Dietary chlorogenic acid| rutin and tomatine levels reflected those occurring naturally in the leaves of tomato| a hostplant of this herbivore. We compared the effects of four thermal regimes having a daytime temperature of 26 degrees C| with the night-time temperature increased from 14 to 26 degrees C by increments of 4 degrees C. The effect of a particular allelochemical on developmental rate was similar among the four thermal regimes. Chlorogenic acid and tomatine each reduced final larval weight| but there was no effect of night-time temperature. In contrast| rutin had no effect on final weight| whereas final weight declined with increasing night-time temperature. Night-time temperature did not influence amount eaten. Larvae ate less when chlorogenic acid or tomatine was in the diet. For each allelochemical| there were no allelochemical by thermal regime interactions. In addition| we compared the effects of allelochemicals and the thermal regime of 26:14 degrees C and constant 20 degrees C| which was the average temperature of the 26:14 degrees C regime. Developmental rate was lower at the constant 20 degrees C regime| chlorogenic acid and tomatine each depressed developmental rate| and there were no allelochemical by thermal regime interactions. Thus| regardless of the specific allelochemical or amount| the pattern of response at the fluctuating regime was similar to that at the constant temperature. In contrast| comparison of the thermal regime of 26:22 degrees C and constant 24 degrees C| which was the average temperature of the 26:22 degrees C regime| showed several allelochemical by thermal regime interactions. At the 26:22 degrees C regime| developmental rate was disproportionatly higher at the maximal rutin concentration compared to that at constant 24 degrees C. At the constant 24 degrees C| final larval mass was disproportionately lower at the moderate tomatine concentration compared to that at the 26:22 degrees C regime. Because these results differ from that of other studies examining another species| it appears that the response to incremental changes in night-time temperature will reflect the allelochemicals and insect species tested. The contrast between the constant 24 degrees C and 26:22 degrees C regimes indicates that even small fluctuations (+/-2 degrees C) in temperature over 24 h can yield differences in the response to an allelochemical. 4861,1997,2,4,Combined effects of night-time temperature and allelochemicals on performance of a Solanaceae specialist herbivore,To assess the influence of temperature on the impact of allelochemicals on the growth of insect herbivores. we examined the interactions between allelochemicals and warmer night-time temperatures on an insect herbivore| Manduca sexta (L.) and tomato plants. We compared the effects of four thermal regimes with a standard day-time temperature of 26 degrees C and the night-time temperature varying from 14 to 26 degrees C by increments of 4 degrees C. Increasing concentrations of chlorogenic acid and tomatine reduced developmental rate linearly. At 26:22 degrees C| there was also a quadratic effect| such that intermediate concentrations had a disproportionately large negative effect. Furthermore| the negative effects of the allelochemicals were less at the 26:14 degrees C regime. These results differ from another study examining a different insect species| which suggests that the response to incremental changes in night-time temperature will vary with the allelochemicals and insect species tested. However. some consistent patterns for M. sexta have emerged. The negative effects on caterpillar development of increasing allelochemical concentration changed across the gradient in night-time temperatures. At one thermal regime (26:22 degrees C)| M. sexta growth was disproportionately reduced by intermediate concentrations of each of three allelochemicals tested. 2446,1997,2,2,Community composition in mountain ecosystems: climatic determinants of montane butterfly distribution,Montane butterfly densities and species assemblages vary widely over space and through time. This variation is partially driven by variation in weather and climate| at spatial scales ranging from local habitats to regional ecosystems| and over time spans of days to centuries. We present case studies that illustrate how climatic variation affects individuals| population densities and species' ranges| and species distribution patterns at the regional level. Present patterns at all scales are neither spatially nor temporally static| even in the absence of directional anthropogenic climate change. The observed patterns allow us to sketch the broad outline of expected changes in population densites| species distributions and butterfly community composition under anthropogenic climate change. We conclude that the fragmented habitats found in montainous areas will exacerbate the effects of climate change on population densities and species' survival| and that relatively sedentary species require closer attention from conservation biologists. 4870,1997,3,4,Comparison of energy sources in terms of their full energy chain emission factors of greenhouse gases,This paper deals with the methodologies and databases for comparative assessment of emissions of greenhouse gases (GHGs) from the full energy chain (FENCH) of different energy sources| It largely refers to an international experts workshop on the topic held in October 1994 in Beijing| which was the first meeting in a series of IAEA expert meetings on comparison of FENCH-GHG emission from energy sources| The findings and recommendations of the workship cover topics such as time horizon| plant life time| materials flows and system output comparability. Copyright (C) 1997 Elsevier Science Ltd. 2455,1997,3,3,Compensating for opportunity costs in forest-based global climate change mitigation,Compensation to developing countries for mitigating global climate change by conserving forest or improving forest management should include the opportunity cost of foregone national development and not just the cost of carbon stored.Estimation of the opportunity cost is discussed and alternative compensation schemes compared. 2434,1997,2,4,Compositional and functional shifts in microbial communities due to soil warming,Microbial decomposition processes are typically described using first-order kinetics| and the effect of elevated temperature is modeled as an increase in the rate constant. However| there is experimental data to suggest that temperature increases the pool size of substrate C available for microbial respiration with little effect on first-order rate constants. We reasoned that changes in soil temperature alter the composition of microbial communities| wherein dominant populations at higher temperatures have the ability to metabolize substrates that are not used by members of the microbial community at lower temperatures. To gain insight into changes in microbial community composition and function following soil warming| we used molecular techniques of phospholipid Patty acid (PLFA) and lipopolysaccharide fatty acid (LPS-OHFA) analysis and compared the kinetics of microbial respiration for soils incubated from 5 to 25 degrees C. Substrate pools for microbial respiration and the abundance of PLFA and LPS-OHFA biomarkers for Gram-positive and Gram-negative bacteria differed significantly among temperature treatments| providing evidence for a shift in the function and composition of microbial communities related to soil warming. We suggest that shifts in microbial community composition following either large seasonal variation in soil temperature or smaller annual increases associated with global climate change have the potential to alter patterns of soil organic matter decomposition by a mechanism that is not considered by current simulation models. 4716,1997,3,3,Computer modelling of the rural energy system and of CO2 emissions for Bangladesh,We present projections of rural energy supply and demand and assess the contributions to global warming. The output of a dynamic system model is used in the LEAP model and overall energy balances are then compiled using a bottom-up approach. Biomass fuels constitute the major energy sources for rural people. A major share of the fuel is consumed for cooking using traditional stoves which have an efficiency less than 10%. Most of the biomass comes from crop wastes. Conservative estimates show tremendous pressure on rural forests for fuelwood. As the result| there is overcutting of rural forests resulting in environmental degradation. Bangladesh is responsible for a small fraction of the total anthropogenic contribution of CO2 but could be seriously affected by climatic change. Energy planning for sustainable development with LEAP is made more effective by using a complementary dynamic system model. (C) 1997 Elsevier Science Ltd. 2456,1997,3,4,Conceptual issues related to carbon sequestration: Uncertainty and time,Global climate change is about uncertainty related to ecological and economic processes| and political responses. It is about fairness and income distribution among nations| both now and in the future. It is a dynamic problem that involves national carbon transition functions| damage functions and discount rates. These issues form the basis of the current paper| which examines them from a conceptual point of view. 4736,1997,3,2,Concrete and sustainable development,The first signs of global warming caused by the greenhouse effect are now apparent. In the near future| a new evaluation of building materials in light of their ability to fulfill the requirements of sustainable development will be required In this paper; the energy consumption and greenhouse gas emissions of concrete in residential buildings will be examined| taking into consideration production and operational phases| as well as traffic-induced energy consumption and emissions in residential areas. The massiveness of concrete buildings causes significant energy and emission savings compared to buildings comprised of lighter materials. This improves the ecological balance of concrete and lifts it to the group of building materials which burden the environment least. 4799,1997,2,4,Decadal changes of inflow to the Sacramento San Joaquin delta| California,The Sacramento-San Joaquin Delta is both an important environmental resource and a critical link in the water supply system for California. Concern for the adequacy of Delta water supplies increases with growing population and environmental maintenance needs and with the hydroclimatic uncertainty of global warming. Reconstructed or unimpaired discharges for Delta tributary areas are analyzed for trend and for changes in the seasonal regime of Delta inflows. Nonparametric tests indicate the absence of trend for annual inflows| but the low inflow months of September and October display increasing trends that are statistically significant. Additional changes in the Delta inflow regime are evident when inflow volumes are expressed relative to annual inflow. Decreasing trends in the spring fraction of annual total inflows and in the monthly fractions for April and May are statistically significant. March displays a significant increasing trend in the monthly fraction of inflow. The emerging decadal changes in monthly inflows have practical ramifications for water managers in the Delta. 4804,1997,4,4,Decision analysis of shoreline protection under climate change uncertainty,If global warming occurs| it could significantly affect water resource distribution and availability. Yet it is unclear whether the prospect of such change is relevant to water resources management decisions being made today. We model a shoreline protection decision problem with a stochastic dynamic program (SDP) to determine whether consideration of the possibility of climate change would alter the decision. Three questions are addressed with the SDP: (1) How important is climate change compared to other uncertainties?| (2) What is the economic loss if climate change uncertainty is ignored?| and (3) How does belief in climate change affect the timing of the decision? In the case study| sensitivity analysis shows that uncertainty in real discount rates has a stronger effect upon the decision than belief in climate change. Nevertheless| a strong belief in climate change makes the shoreline protection project less attractive and often alters the decision to build it. 2381,1997,4,4,Detection and parameterization of variations in solar mid- and near-ultraviolet radiation (200-400 nm),Nimbus 7 and Solar Stellar Irradiance Comparison Experiment (SOLSTICE) spacecraft measurements of solar irradiance both exhibit variability at mid (200-300 nm) and near (309-400 nm) ultraviolet (UV) wavelengths that are attributable to the Sun's 27-day solar rotation| even though instrument sensitivity drifts obscure longer-term| 11-year cycle variations| Competing influences of dark sunspots and bright faculae are the dominant causes of this rotational modulation| Parameterizations of these influences using a newly developed UV sunspot darkening index and the Mg index facular proxy replicate the rotational modulation detected in both the broadband Nimbus 7 filter data (275-360 nm and 300-410 nm) and in SOLSTICE l-nm spectra from 200 to 400 nm. Assuming that these rotational modulation influences scale linearly over the solar cycle| long-term databases of sunspot and global facular proxies permit estimation of Ii-year cycle amplitudes of the mid-and near-UV solar spectrum| unmeasured at wavelengths longward of 300 nm because of insufficient long-term repeatability (relative accuracy) of state-of-the-art solar radiometers at these wavelengths. Reconstructions of UV irradiances throughout the Ii-year solar cycle indicate variabilities of 0.173 W/m(2) (1.1%) in the integrated radiation from 200 to 300 nm and 0.24 W/m(2) (0.25%) in radiation from 300 to 400 nm| These two UV bands thus contribute about 13% and 18%| respectively| to the 1.54 W/m(2) (0.1%) total (spectrally integrated) radiative output solar cycle. The parameterizations allow customization of UV irradiance time series for specific wavelength bands required as inputs to general circulation model simulations of solar cycle forcing of global climate change| and have practical implications regarding the long-term repeatability required for future solar monitoring. 4866,1997,3,4,Development of a photobioreactor incorporating Chlorella sp. for removal of CO2 in stack gas,We developed a new design photobioreactor incorporating Chlorella sp. for removal of CO2 in stack gas. Photosynthetic conversion of CO2 into Chlorella biomass was investigated in a photobioreactor| which we termed a cone-shaped helical tubular photobioreactor. The laboratory scale photobioreactor (0.48 m high X 0.57 m top diameter) was set up with a 0.255 m(2) installation area. The photostage was made from transparent polyvinyl chloride (PVC) tubing (1.6 cm internal diameter with 2 cm wall thickness and 27 m in length). The inner surface of the cone-shaped photostage (0.50 m(2)) was illuminated with a metal halide lamp| the energy input into the photostage[photosynthetically active radiation (PAR| 400-700 nm)] was 2127 KJ day(-1) (12 h day / 12 h night). The maximum daily photosynthetic efficiency was 5.67% (PAR) under an air-lift operation at a flow rate of 0.3 litre min(-1) 10% CO2 enriched air. Maximum increase of Chlorella biomass was 21.5 g dry biomass m(-2) (installation area) day(-1) or 0.68 g dry biomass litre medium(-1) day(-1). Also| a helical tubular photobioreactor for outdoor culture was constructed with a 1.1 m(2) installation area (1.2 m top diameter) and photosynthetic productivity was investigated in July| 1996. (C) 1997 Elsevier Science Ltd. 4699,1997,3,2,Development of new estimation method for CO2 evolved from oil shale,It is widely proposed that the global warming is mainly caused by the increase in of carbon dioxide (CO2) content in the atmosphere| and that fossil fuels are the dominant sources of this CO2. Therefore| the quality of fossil fuels tends to be evaluated by amounts of CO2 emissions. For the evaluation of an oil shale from this point an on-line thermogravimetric-gas chromatographic system was used to measure CO2 evolution profiles on temperature with a small oil shale sample. This method makes possible to estimate the amounts of CO2 evolved from kerogen and carbonates in retorting and those from carbonates in combustion| respectively. These results will be basic data for a novel oil shale retorting process for the control of CO2 emissions. The profiles for Thai and Colorado oil shales have shown CO2 mainly evolved by the pyrolysis of kerogen below 550 degrees C| and that evolved by the decomposition of carbonates above that temperature. On the other hand| the profile for Condor oil shale showed that most carbonates decomposed below 550 degrees C| while only small amounts of carbonates decomposed above this temperature. (C) 1997 Elsevier Science B.V. 4841,1997,4,4,Dimethylsulfoniopropionate in anoxic intertidal sediments: A precursor of methanogenesis via dimethyl sulfide| methanethiol| and methiolpropionate,The most important volatile sulfur compound in the marine environment is dimethyl sulfide (DMS)| which mainly originates from the algal osmolyte dimethylsulfoniopropionate (DMSP). Conversion of DMSP in anoxic marine sediments involves a cleavage to acrylate and DMS| which can further be converted by methanogenic Archaea and possibly by sulfate-reducing bacteria| or a demethylation to 3-methiolpropionate (MMPA); MMPA can be demethylated to 3-mercaptopropionate or demethiolated to methanethiol and presumably acrylate. Little is known about the types of anaerobic microorganisms that are involved in the demethylation pathway. We found that the marine Desulfobacterium strain PM4 converts DMSP to MMPA and that three marine Methanosarcina strains demethylate MMPA to S-mercaptopropionate and methane. Methanogenic conversion of MMPA in anoxic sediment slurries was only found when antibiotics that inhibit Bacteria but not Archaea were added. Under non-inhibited conditions MMPA was rapidly converted to methanethiol and subsequently to methane. The numbers of MMPA-metabolizing methanogens were significantly lower than those of DMS-| trimethylamine-| or methanol-metabolizing methanogens. It is concluded that in anoxic intertidal sediments DMSP is not only a source of DMS with its well-known counteractive effect on global warming| but also of the potent greenhouse gas methane. 4805,1997,2,4,Distinguishing between the effects of changes in temperature and light climate using provenance trials with Pinus sylvestris in Sweden,Provenance trials have been used to project the response of forest trees to changes in temperature resulting from the expected global warming. In such experiments the differences in temperature are brought about through geographical transfers over altitude and latitude. Transfers over latitudinal distances are also accompanied by changes in light climate. To distinguish between the effects of temperature and light| studies were made in a Pious sylvestris. L. provenance series in Sweden: in the series both the sites and the provenances are distributed over large latitudinal and altitudinal ranges. The response to annual temperature sum and latitude were calculated using multiple regression analysis| Both projected dominant height at age 100 years (H100) and mean annual yield increment over the rotation responded linearly to increasing temperature sum. The response to temperature sum decreased with increasing southward transfer. Latitudinal transfers without changes in temperature sum did not affect the performance of the populations. The projected response of populations to gradual warming will be less than projected on the basis of the final or the average temperature sums over the rotation period. 4735,1997,2,4,Distribution of bryophytes on subantarctic Heard Island,Heard Island is a small| isolated subantarctic island dominated by art ice covered volcano. Glaciers descend the volcano to the sea. Coastal ice free areas of tundra are present separated from each other by glaciers. Each of these areas cart be considered as individual islands and Heard Island art archipelago. The distribution of 49 bryophyte taxa across five major and four minor ice-free areas was examined. Fifty percent of the bryophyte taxa exhibited widespread distribution| occurring on all ice-free islands examined Absence of some conspicuous species from particular areas appeared to reflect situations where limited habitat variation has restricted the establishment of species. With present global warming| glacial retreat on Heard Island is rapid. Consequently| areas suitable for colonization by plants are increasing and previously separated ice free areas are now merging. This study provides baseline data against which future studies will be able to investigate possible changes in bryophyte species diversity and distribution on Heard Island.
4727,1997,2,4,Ditylenchus dipsaci infestation of Trifolium repens .2. Dynamics of infestation development,Trifolium repens (white clover) stolons were inoculated with Ditylenchus dipsaci (stem nematode)| and the development of resulting infestations was monitored. Nematodes initially remained confined to superficial locations| concentrating in petiole axils near inoculation points. They were able to migrate slowly from the initial inoculation points and infest adjacent axils| especially in regions near the stolen tip. As time progressed| in some axils| nematodes migrated through the stolen epidermis and colonized slowly expanding subepidermal pockets of host tissue (ca| 0.2-mm length of stolon/day). In these loci nematodes established exponentially increasing populations| but the rates of locus expansion remained constant| indicating that locus expansion was limited by unidentified host-dependent factors. As a result of increasing population pressure within subepidermal loci| J4 entered a ''diapause'' state and the rate of egg production by adults declined| thereby reducing rate of population growth to more sustainable levels. Typically| these populations peaked at ca. 10|000 individuals in ca. 160 days occupying S-cm lengths of stolen. Thereafter| heavily infested regions of stolons started to die| leading to the formation of longitudinal splits in their epidermis. In other axils| nematodes did not migrate into the stolons but remained confined to axils. Some of these populations increased a hundred-fold in 95 days| with population growth ending when petioles started to die. Host plant stolen morphology was affected only when subepidermal stolen populations developed high population levels (>100 nematodes) within close proximity (<2 cm) to active terminal meristems. This occurred either when axillary buds became active on previously infested nodes or when nematodes established endoparasitic populations at locations near the stolen tip during winter and spring| when the rate of stolen extension was limited by low light intensity. Affected stolen tips could ''escape'' from the influence of such infestations when light intensity and temperature increased. Nematode activity was limited by low temperature rather than light intensity. Global warming is likely to lead to greater damage to infested plants during the winter and early spring because the predicted milder winter temperatures will enhance nematode activity but not necessarily promote stolen growth. 4832,1997,4,3,Early development in the study of greenhouse warming: The emergence of climate models,Following the pioneering contributions of Arrhenius| Callendar and others| climate models emerged as a very promising tool for the study of greenhouse warming. In the early 1960s| a one-dimensional| radiative-convective equilibrium model was developed as the first step towards the development of a three-dimensional model of climate. Incorporating not only the radiative but also the convective heat exchange between the earth's surface and the atmosphere| the model overcame the difficulty encountered by the earlier approach of surface radiative heat balance in estimating the magnitude of greenhouse warming. By the 1970s| a three-dimensional| general circulation model (GCM) of the atmosphere| coupled to a very idealized ocean of swamp-like wet surface| had been used for studies of greenhouse warming. Despite many drastic simplifications| the GCM was very effective for elucidating the physical mechanisms that control global warming and served as a stepping stone towards the use of more comprehensive| coupled ocean-atmosphere GCMs for the study of this problem. 4791,1997,3,2,Eco-efficiency: A prerequisite for future success,At Roche| eco-efficiency - the optimal use of material| energy| human resources| and capital to supply innovative products to the market - is considered as a prerequisite for business success in the future. Group-wide activities to rise eco-efficiency are focussed on manufacturing processes rather than on product design| since chemical composition and structure of the Roche pharmaceutical products are defined by the desired therapeutic effect| in contrast to commodities. Three examples of currently operating eco-efficient processes at Roche are described. They cover main areas for further improvement of both environmental performance and economical benefit: less material intensity and waste for disposal| energy recovery| minimization of water consumption. Furthermore| four different indicators currently used at Roche to track environmental performance and eco-efficiency are presented: the Roche Environmental Impact Figure (REIF)| the Roche Energy Rate (RER)| the Roche contribution to man-made global warming (CO2 equivalents)| and the Eco-Efficiency Rate. (EER). These key indicators are used as a basis to recognize weaknesses and strengths| to take decisions for improvement| to set environmental targets| and as management information. 2405,1997,2,4,Ecosystem evaluation| climate change and water resources planning,This paper considers ecosystem evaluation under conditions of climate change in the context both of the U.S. Water Resources Council's Principles and Guidelines (P&G) and the more general Federal regulations governing environmental evaluation. Federal water agencies have responsibilities for protecting aquatic ecosystems through their regulatory programs and operations and planning missions. The primary concern of water resources and aquatic ecosystems planning in the United States is on the riparian or floodplain corridors of river systems. In the context of climate change| planning for these systems focusses on adaptation options both for current climate variability and for that engendered by potential climate change. Ecosystems appear to be highly vulnerable to climate change| as described in IPCC reports. Aquatic ecosystems are likely to be doubly affected| first by thermally induced changes of global warming and second by changes in the hydrologic regime. Perhaps as much as any of the issues dealt with in this issue| the evaluation of ecosystems is linked to fundamental questions of criteria as well as to the details of the Federal environmental planning system. That system is a densely woven| interlocking system of environmental protection legislation| criteria and regulations that includes a self-contained evaluation system driven by the National Environmental Policy Act (NEPA) procedural guidelines (United States Council on Environmental Quality| 1978) and Environmental Impact Statement (EIS) requirements. The Corps of Engineers must use both the P&G and the NEPA/EIS system in discharging its responsibilities. If U.S. Federal agencies are to take the lead in formulating and evaluating adaptation options| there needs to be a reexamination of existing evaluation approaches. Among the elements of the P&G that may require rethinking in view of the prospects of global climate change are those relating to risk and uncertainty| nonstationarity| interest rates| and multiple objectives. Within the government planning process| efforts must be made to resolve inconsistencies and constraints in order to permit the optimal evaluation of water-based ecosystems under global climate change. The interrelationships of the two systems are described in this paper| and alternative ways of viewing the planning process are discussed. Strategic planning and management at the watershed level provides an effective approach to many of the issues. Current NEPA/EIS impact analysis does not provide a suitable framework for environmental impact analysis under climate uncertainty| and site-specific water resources evaluation relating to climate change appears difficult at current levels of knowledge about climate change. The IPCC Technical Guidelines| however| provide a useful beginning for assessing the impacts of future climate states. 4764,1997,4,4,Eddy parametrization and the oceanic response to idealized global warming,A coarse-grid global ocean general circulation model (OGCM) is used to determine the role of sub-grid scale eddy parametrization schemes in the response to idealized changes in the surface heat flux| of the same order as expected under increased atmospheric CO2 concentrations. Two schemes are employed. The first (H) incorporates standard horizontal mixing| whereas the second (G) combines both enhanced isopycnal mixing and eddy-induced transport. Uniform surface heating anomalies of + 2Wm(-2) and - 2Wm(-2) are applied for 50 years| and the results are compared with a control experiment in which no anomalous heating is imposed. A passive ''heat'' tracer is applied uniformly (at a rate of 2Wm(-2) for 50 years) in a separate experiment. The sea-surface temperature response to global surface heating is generally larger in G| especially in the northern subtropical gyres| along the southern coast of Australia and off the Antarctic coast. A pronounced interhemispheric asymmetry (primarily arising from an anomalous response south of 35 degrees S) is evident in both H and G. The surface trapping of passive tracers in the Southern Hemisphere is generally greater in G than it is in H| and is particularly pronounced along the prime meridian (0 degrees E). Dynamical changes (i.e.| changes in horizontal and vertical currents| convection| and preferred mixing: and eddy transport pathways) enhance surface warming in the tropics and subtropics in both G and H. They are dominated by an anomalous meridional overturning centred on the equator| which may also operate in greenhouse warming experiments using coupled atmosphere-ocean GCMs. Over the Southern Ocean the passive tracer experiments and associated ventilation rates suggest that surface warming will be greater in G than in H. In fact| the contrast between the dynamical responses evident in G and H in the actual heating experiments leads to a situation in which the reverse is often true. Overall| dynamical changes enhance the interhemispheric assymetry| more so in G than in H. 4698,1997,2,4,Effects of a temperature increase in a field experiment on the nitrogen release from soil cores with different humus forms,Global warming could have far-reaching consequences for the properties of soils. From the available knowledge it is postulated that an increase in temperature (ail other climatic conditions unchanged) will decrease the nitrogen contents until a new equilibrium is reached. To test this hypothesis we established in the 'Tegernsee Alps' a field experiment. In spruce-dominated montane forests 60 undisturbed soil cores (= monoliths) were carefully digged out at 1250 and 1320 m asl and reestablished at 3 elevations (1250 m and 1010 m and at 740 m asl) corresponding to a warming of around 1 and 2 degrees C. At each slope position we investigated a Dystric Cambisol with raw humus (RH) and another one with moder (MO). Each of these 6 trial-variants therefore was represented by 10 monoliths. From August 1992 to December 1995 seepage water was sampled by suction cups every 2 or 4 weeks and analyzed for the concentrations of important bioelements including aluminum| pH and electrical conductivity. After translocation to warmer climates additional nitrogen was released from both soil forms mainly as nitrate. The Cambisol with the more active humus form moder reacted stronger than the one with raw humus (additional output > 40 vs. 34 kg ha(-1) a(-1); +2 degrees C). In both soil forms the N release was accelerated in summer| in RH by 55 to 92 and in MO by 37 to 86 ppm. The Cambisol with moder showed higher nitrate leaching also in winter and thus was superior with regard to the total annual N output. In all cases Al was the most important associated cation to NO3- with 75% (RH) and 54% (MO) of the cation equivalent sum respectively The experiment thus confirms a substantial increase of nitrification even by a temperature increase of only 1 and 2 degrees C| which in permeable| well aerated sails should lead to increased nitrate leaching under conditions where no vegetation is interfering. 4721,1997,2,4,Effects of chronic environmental acidification and a summer global warming scenario: protein synthesis in juvenile rainbow trout (Oncorhynchus mykiss),Protein synthesis (K-s)| net accretion (K-g)| and degradation (K-d) in liver| gills| and white muscle were measured using a flooding dose of [H-3]phenylalanine in juvenile rainbow trout chronically exposed (90 days) to softwater in the presence or absence of sublethal acidity (H2SO4| pH 5.2) alone or in combination with a 2 degrees C elevation in the normal temperature profile over the months of June-September 1993 (control temperature range 13-24 degrees C). Chronic sublethal exposure to low pH reduced protein synthesis and degradation in both the gill and liver with little apparent impact on white muscle. As a result| protein was increased in the affected tissues. This suggested that both liver and gill have some capacity to compensate for the effects of acid exposure. The 2 degrees C elevation in the normal temperature profile resulted in a slight increase in protein turnover in both gills and liver. However| during the period of peak water temperature| the 2 degrees C elevation in temperature triggered a dramatic reduction in the protein turnover rates in these tissues. The exact mechanism by which these modifications in protein turnover occurred could not be clearly established. Overall| environmental acidification in combination with a summer global warming scenario would decrease fish growth and survival| most notably during periods of peak temperatures. 4770,1997,2,4,Effects of climate change on inland waters of the Pacific Coastal Mountains and Western Great Basin of North America,The region designated as the Pacific Coastal Mountains and Western Great Basin extends from southern Alaska (64 degrees N) to southern California (34 degrees N) and ranges in altitude from sea level to 6200 m. Orographic effects combine with moisture-laden frontal systems originating in the Pacific Ocean to produce areas of very high precipitation on western slopes and dry basins of internal drainage on eastern hanks of the mountains. In the southern half of the region most of the runoff occurs during winter or spring| while in the northern part most occurs in summer| especially in glaciated basins| Analyses of long-term climatic and hydrological records| combined with palaeoclimatic reconstructions and simulations of future climates| are used as the basis for likely scenarios of climatic variations. The predicted hydrological response in northern California to a climate with doubled CO2 and higher temperatures is a decrease in the amount of precipitation falling as snow| and substantially increased runoff during winter and less in late spring and summer. One consequence of the predicted earlier runoff is higher salinity in summer and autumn in San Francisco Bay. In saline lakes| the incidence of meromixis and the associated reduction in nutrient supply and algal abundance is expected to vary significantly as runoff fluctuates. In subalpine lakes| global warming will probably will lead to increased productivity. Lacustrine productivity can also be altered by changes in wind regimes| drought-enhanced forest fires and maximal or minimal snowpacks associated with atmospheric anomalies such as Fl Nino-Southern Oscillation (ENSO) events. Reduced stream temperature from increased contributions of glacial meltwater and decreased channel stability from changed runoff patterns and altered sediment loads has the potential to reduce the diversity of zoobenthic communities in predominately glacier-fed rivers. Climatic warming is likely to result in reduced growth and survival of sockeye salmon in freshwater| which would| in turn| increase marine mortality. Further research activities should include expanded studies at high elevations and of glacier mass balances and glacial runoff| applications of remote sensing to monitor changes| further refinement of regional climatic models to improve forecasts of future conditions and continued analyses of long-term physical| chemical and biological data to help understand responses to future climates. (C) 1997 by John Wiley & Sons| Ltd. 4769,1997,4,3,Effects of climate change on the freshwaters of arctic and subarctic North America,Region 2 comprises arctic and subarctic North America and is underlain by continuous or discontinuous permafrost. Its freshwater systems are dominated by a low energy environment and cold region processes. Central northern areas are almost totally influenced by arctic air masses while Pacific air becomes more prominent in the west| Atlantic air in the east and southern air masses at the lower latitudes. Air mass changes will play an important role in precipitation changes associated with climate warming. The snow season in the region is prolonged resulting in long-term storage of water so that the spring flood is often the major hydrological event of the year| even though| annual rainfall usually exceeds annual snowfall. The unique character of ponds and lakes is a result of the long frozen period| which affects nutrient status and gas exchange during the cold season and during thaw. GCM models are in close agreement for this region and predict temperature increases as large as 4 degrees C in summer and 9 degrees C in winter for a 2 x CO? scenario. Palaeoclimate indicators support the probability that substantial temperature increases have occurred previously during the Holocene. The historical record indicates a temperature increase of >1 degrees C in parts of the region during the last century. GCM predictions of precipitation change indicate an increase| but there is little agreement amongst the various models on regional disposition or magnitude. Precipitation change is as important as temperature change in determining the water balance. The water balance is critical to every aspect of hydrology and limnology in the far north. Permafrost close to the surface plays a major role in freshwater systems because it often maintains lakes and wetlands above an impermeable frost table| which limits the water storage capabilities of the subsurface. Thawing associated with climate change would| particularly in areas of massive ice| stimulate landscape changes| which can affect every aspect of the environment. The normal spring flooding of ice-jammed north-flowing rivers| such as the Mackenzie| is a major event| which renews the water supply of lakes in delta regions and which determines the availability of habitat for aquatic organisms. Climate warming or river damming and diversion would probably lead to the complete drying of many delta lakes. Climate warning would also change the characteristics of ponds that presently freeze to the bottom and result in fundamental changes in their limnological characteristics. At present| the food chain is rather simple usually culminating in lake trout or arctic char. A lengthening of the growing season and warmer water temperature would affect the chemical| mineral and nutrient status of lakes and most likely have deleterious effects on the food chain. Peatlands are extensive in region 2. They would move northwards at their southern boundaries| and| with sustained drying| many would change form or become inactive| Extensive wetlands and peatlands are an important component of the global carbon budget| and warmer and drier conditions would most likely change them from a sink to a source for atmospheric carbon. There is some evidence that this may be occurring already. Region 2 is very vulnerable to global warming. Its freshwater systems are probably the least studied and most poorly understood in North America. There are clear needs to improve our current knowledge of temperature and precipitation patterns; to model the thermal behaviour of wetlands| lakes and rivers; to understand better the interrelationships of cold region rivers with their basins; to begin studies on the very large lakes in the region; to obtain a firm grasp of the role of northern peatlands in the global carbon cycle; and to link the terrestrial water balance to the thermal and hydrological regime of the polar sea. Overall there is a strong need for basic research and long-term monitoring. (C) 1997 by John Wiley & Sons| Ltd. 2461,1997,2,4,Effects of elevated CO2 and temperature on photosynthesis and Rubisco in rice and soybean,Rice (Oryza sativa L. cv. IR-72) and soybean (Glycine max L. Merr. cv. Bragg)| which have been reported to differ in acclimation to elevated CO2| were grown for a season in sunlight at ambient and twice-ambient [CO2]| and under daytime temperature regimes ranging from 28 to 40 degrees C. The objectives of the study were to test whether CO2 enrichment could compensate for adverse effects of high growth temperatures on photosynthesis| and whether these two C-3 species differed in this regard. Leaf photosynthetic assimilation rates (A) of both species| when measured at the growth [CO2]| were increased by CO2 enrichment| but decreased by supraoptimal temperatures. However| CO2 enrichment more than compensated for the temperature-induced decline in A. For soybean| this CO2 enhancement of A increased in a linear manner by 32-95% with increasing growth temperatures from 28 to 40 degrees C| whereas with rice the degree of enhancement was relatively constant at about 60%| from 32 to 38 degrees C. Both elevated CO2 and temperature exerted coarse control on the Rubisco protein content| but the two species differed in the degree of responsiveness. CO2 enrichment and high growth temperatures reduced the Rubisco content of rice by 22 and 23%| respectively| but only by 8 and 17% for soybean. The maximum degree of Rubisco down-regulation appeared to be limited| as in rice the substantial individual effects of these two variables| when combined| were less than additive. Fine control of Rubisco activation was also influenced by both elevated [CO2] and temperature. In rice| total activity and activation were reduced| but in soybean only activation was lowered. The apparent catalytic turnover rate (K-cat) of rice Rubisco was unaffected by these variables| but in soybean elevated [CO2] and temperature increased the apparent K-cat by 8 and 22%| respectively. Post-sunset declines in Rubisco activities were accelerated by elevated [CO2] in rice| but by high temperature in soybean| suggesting that [CO2] and growth temperature influenced the metabolism of 2-carboxyarabinitol-1-phosphate| and that the effects might be species-specific. The greater capacity of soybean for CO2 enhancement of A at supraoptimal temperatures was probably not due to changes in stomatal conductance| but may be partially attributed to less down-regulation of Rubisco by elevated [CO2] in soybean than in rice. However| unidentified species differences in the temperature optimum for photosynthesis also appeared to be important. The responses of photosynthesis and Rubisco in rice and soybean suggest that among C-3 plants species-specific differences will be encountered as a result of future increases in global [CO2] and air temperatures. 2388,1997,2,4,Effects of experimental warming on arctic willows (Salix spp.): A comparison of responses from the Canadian High Arctic| Alaskan Arctic| and Swedish Subarctic,Three species of dwarf| prostrate willow (Salix arctica| S. rotundifolia and S. herbacea) were subjected to experimental summer warming in high arctic Canada| arctic Alaska| and subarctic Sweden| respectively| as part of the International Tundra Experiment. Phenological and growth responses of these species were compared for the second season of the experiment. Stigmas became receptive and pollen dispersal occurred significantly earlier for S. rotundifolia and S. herbacea in the ITEX open-top chambers| but not for S. arctica. Warming had no effect on the timing of seed dispersal| leaf yellowing| or leaf senescence. The length and dry weight of the largest leaves were greater for warmed plants| and was significant for S. rotundifolia. The number of catkins/plot did not differ among species or treatments| but the fruit:newer ratio was reduced in the experimental plots. 4750,1997,2,4,Effects of flowering time and temperature on growth and reproduction in Leontodon autumnalis var. taraxaci a late-flowering alpine plant,In most alpine and arctic plants there is selection for early flowering because of the short time available to complete seed production before the season terminates. Despite this| some species initiate flowering late in the season| but little work has been done on the reproductive ecology of such species. This work investigates the reproductive consequences of late flowering in Leontodon autumnalis var. taraxaci in alpine southwest Norway during two seasons. In addition| the effects of an experimental increase in growing-season temperature on growth and reproduction are also examined. The reproductive success of Leontodon decreased strongly as the flowering season progressed| possibly as a result of increased climatic severity and increased extent of pollen and resource limitation on reproduction. Experimentally warmed plants produced significantly more and heavier seeds| and flowered more than 1 wk earlier than control plants| showing that temperature conditions influence both reproductive processes and flowering phenology. The results suggest that this late-flowering alpine species will bloom earlier| reproduce more| and grow larger under global warming. 2462,1997,2,4,Effects of increasing UV-B radiation and atmospheric CO2 on photosynthesis and growth: Implications for terrestrial ecosystems,Increases in UV-B radiation reaching the earth as a result of stratospheric ozone depletion will most likely accompany increases in atmospheric CO2 concentrations. Many studies have examined the effects of each factor independently| but few have evaluated the combined effects of both UV-B radiation and elevated CO2. In general the results of such studies have shown independent effects on growth or seed yield. Although interspecific variation is large| high levels of UV-B radiation tends to reduce plant growth in sensitive species| while CO2 enrichment tends to promote growth in most C-3 species. However| most previous studies have not looked at temporal effects or at the relationship between photosynthetic acclimation to CO2 and possible photosynthetic limitations imposed by UV-B radiation. Elevated CO2 may provide some protection against UV-B for some species. In contrast| UV-B radiation may limit the ability to exploit elevated CO2 in other species. Interactions between the effects of CO2 enrichment and UV-B radiation exposure have also been shown for biomass allocation. Effects on both biomass allocation and photosynthetic acclimation may be important to ecosystem structure in terms of seedling establishment| competition and reproductive output. Few studies have evaluated ecosystem processes such as decomposition or nutrient cycling. Interactive effects may be subtle and species specific but should not be ignored in the assessment of the potential impacts of increases in CO2 and W-B radiation on plants. 4879,1997,2,3,Effects of UV-B radiation on terrestrial plants and ecosystems: Interaction with CO2 enrichment,UV-B radiation is just one of the environmental factors| that affect plant growth. It is now widely accepted that realistic assessment of plant responses to enhanced UV-B should be performed at sufficiently high Photosynthetically Active Radiation (PAR)| preferably under field conditions. This will often imply| that responses of plants to enhanced UV-B in the field will be assessed under simultaneous water shortage| nutrient deficiency and variation of temperature. Since atmospheric CO2 enrichment| global warming and increasing UV-B radiation represent components of global climatic change| interactions of UV-B with CO2 enrichment and temperature are particularly relevant. Only few relevant UV-B x CO2 interaction studies have been published. Most of these studies refer to greenhouse experiments. We report a significant CO2 x UV-B interaction for the total plant dry weight and root dry weight of the C-3-grass Elymus athericus. At elevated CO2 (720 mu mol mol(-1))| plant growth was much less reduced by enhanced UV-B than at ambient atmospheric CO2 although there were significant (positive) CO2 effects and (negative) UV-B effects on plant growth. Most other CO2 x UV-B studies do not report significant interactions on total plant biomass. This lack of CO2 x UV-B interactions may result from the fact that primary metabolic targets for CO2 and UVB are different. UV-B and CO2 may differentially affect plant morphogenetic parameters: biomass allocation| branching| flowering| leaf thickness| emergence and senescence. Such more subtle interactions between CO2 and UV-B need careful and long term experimentation to be detected. In the case of no significant CO2 x UV-B interactions| combined CO2 and UV-B effects will be additive. Plants differ in their response to CO2 and UV-B| they respond in general positively to elevated CO2 and negatively to enhanced UV-B. Moreover| plant species differ in their responsiveness to CO2 and UV-B. Therefore| even in case of additive CO2 and UV-B effects| plant competitive relationships may change markedly under current climatic change with simultaneous enhanced atmospheric CO2 and solar UV-B radiation. 4690,1997,3,4,ELA 1.0 - A framework for life-cycle impact assessment developed by the Fraunhofer-Gesellschaft .A. The conceptual framework,The Fraunhofer-Gesellschaft has sponsored the development of a conceptual and flexible| computer aided tool to perform the impact assessment within LCA (life cycle assessment) for technical products and processses. The developed general framework ''Ela 1.0''' (environmental loads analysis) consists of four elements: the selection of appropriate impact categories| the categorization of emissions and wastes leaving the systems as well as of resource and energy consumption| the characterization and an analysis of the results of the impact assessment. The latter compares the product-based emissions with the total of emissions of a region such as Germany| the EU or OECD countries. The framework Ela 1.0 considers the environmental categories: global warming| ozone depletion| resource and energy consumption| wastes| eutrophication (including COD and BOD as measured parameters)| acidification| ecotoxicity| ozone formation and human toxicity. The latter categories are handled by listing of precursors for ozone formation| and by listing of emissions scored according to their human hazard potential. The options| possibilities and limitations of the conceptual framework are presented in part A of a series of publications. (C) 1997 Elsevier Science Ltd. 4782,1997,2,4,Elevated CO2 and moisture effects on soil carbon storage and cycling in temperate grasslands,In grassland ecosystems| most of the carbon (C) occurs below-ground. Understanding changes in soil fluxes induced by elevated atmospheric CO2 is critical for balancing the global C budget and for managing grassland ecosystems sustainably. In this review| we use the results of short-term (1-2 years) studies of below-ground processes in grassland communities under elevated CO2 to assess future prospects for longer-term increases in soil C storage. Results are broadly consistent with those from other plant communities and include: increases in below-ground net primary productivity and an increase in soil C cycling rate| changes in soil faunal community| and generally no increase in soil C storage. Based on other experimental data| future C storage could be favoured in soils of moderate nutrient status| moderate-to-high clay content| and low (or moderately high) soil moisture status. Some support for these suggestions is provided by preliminary results from direct measurements of soil C concentrations near a New Zealand natural CO2-venting spring| and by simulations of future changes in grassland soils under the combined effects of CO2 fertilization and regional climate change. Early detection of any increase in soil C storage appears unlikely in complex grassland communities because of (a) the difficulty of separating an elevated CO2 effect from the effects of soil factors including moisture status| (b) the high spatial variability of soil C and (c) the effects of global warming. Several research imperatives are identified for reducing the uncertainties in the effects of elevated atmospheric CO2 on soil C. 4843,1997,4,3,Elevation dependency of the surface climate change signal: A model study,Results are presented from a present-day and a doubled CO2 experiment over the Alpine region with a nested regional climate model. The simulated temperature change signal shows a substantial elevation dependency| mostly during the winter and spring seasons| resulting in more pronounced waring at high elevations than low elevations. This is caused by a depletion of snowpack in doubled CO2 conditions and further enhanced by the snow-albedo feedback. This result is consistent with some observed temperature trends for anomalously warm years over the Alpine region and suggests that high elevation temperature changes could be used as an early detection tool for global warming. Changes in precipitation| as well as other components of the surface energy and water budgets| also show an elevation signal| which may have important implications for impact assessments in high elevation regions. 4695,1997,3,3,Emissions of N(2)O and NO associated with nitrogen fertilization in intensive agriculture| and the potential for mitigation,Increases in the atmospheric concentrations of nitrous oxide (N(2)O) contribute to global warming and to ozone depletion in the stratosphere Nitric oxide (NO) is a cause of acid rain and tropospheric ozone. The use of N fertilizers in agriculture has direct and indirect effects an the emissions of both these gases| which are the result of microbial nitrification and denitrification in the soil| and which are controlled principally by soil water and mineral N contents| temperature and labile organic matter The global emission of N(2)O from cultivated land is now estimated at 3.5 Tg N annually of which 1.5 Tg has been directly attributed ro synthetic N fertilizers| out of a total quantity applied in 1990 of about 77 Tg N. This amount was 150% above the 1970 figure. The total fertilizer-induced emissions of NO are somewhere in the range 0.5-5 Tg N. Mineral N fertilizers can also be indirect as well as direct sources of N(2)O and NO emissions| via deposition of volatilized NH(3) on natural ecosystems and denitrification of leached nitrate in subsoils| waters and sediments. IPCC currently assume an N(2)O emission factor of 1.25 +/- 1.0% of fertilizer N applied. No allowance is made for different fertilizer types| on the basis that soil management and cropping systems| and unpredictable rainfall inputs| are more important variables. However| recent results show substantial reductions in emissions from grassland by matching fertilizer type to environmental conditions| and in arable systems by using controlled release fertilizers and nitrification inhibitors| Also better timing and placement of N| application of the minimum amount of N to achieve satisfactory yield| and optimization of soil physical conditions| particularly avoidance of excessive wetness and compaction| would be expected to reduce the average emission factor for N(2)O. Some of these adjustments would also reduce NO emissions. However| increasing global fertilizer use is likely to cause an upward trend in total emissions even if these mitigating practices become widely adopted. 4814,1997,3,4,Energy balance of global CO2 recycling and amounts of reduction of CO2 emission,On the basis of tailoring of amorphous alloy electrodes for seawater electrolysis to form H-2 and amorphous alloy catalysts for conversion of CO2 to CH4| we are proposing global CO2 recycling: At deserts; power generation by solar energy| at coasts close to the deserts; production of H-2 by electrolysis of seawater| production of CH4 by the reaction of H-2 and CO2 transported| and at energy consuming districts; combustion of CH4| recovery of CO2 and transportation of liquefied CO2 to the coast close to the deserts. Since Egyptian scientists agree with us to do collaboration| the energy balance and the amount of reduction of CO2 emission in the global CO2 recycling between Middle East and Japan are estimated for the operation of a 1 GW CH4-combustion power plant. The energy consumed in a year up to liquefaction of CH4 including that corresponding to the repayment of solar power plant is almost the same as that spent up to obtaining LNG. The energy necessary for the global CO2 recycling is only 8.7% higher than the energy necessary for LNG combustion for power generation without control of CO2 emission. The extra energy is for recovery| liquefaction and transportation of CO2. The reduction of CO2 emission by the global CO2 recycling is 79% of CO2 emission from an LNG combustion power plant| that is| 2.62 Mtons/year. 4821,1997,4,3,Environment - A liability and an asset for economic development: Some views on environmental protection with economic development in Bhutan,National rights of utilization of natural resources (depletion of primary forest| decrease in range of biodiversity| etc.) and rights of polluting the 'global commons'| contributing to global warming| depletion of the ozone layer| etc.| have become central themes in today's international debate. For a small| least-developed country like Bhutan| which began modern economic development only 35 years ago after centuries of self-imposed isolation and hence still has most of its natural resources and environment intact| the question is how to spur much needed economic growth while preserving its pristine environment. Rapid population growth and the desire for economic development in a rugged mountainous terrain imposes a potential threat to the environment. Bhutan's National Environment Strategy has identified intersectoral contradictions and possible synergies in resource utilization and the need for institutional reforms| policies| manpower development| information| and legislation to achieve the goal of balanced sustainable development. The challenge ahead is the implementation of this strategy| as environmental regulations must be fitted into the society's economic and social structure. While promoting economic development| preservation of the environment can easily become a liability to Bhutan. There is the great danger that Bhutan's unique environment will come to be seen by other nations as just another unexploited asset. 2445,1997,3,4,Environmental advantages to the utilization of geothermal energy,Geothermal energy is a technically-proven| cost effective source of electrical and thermal energy that has been utilized for many decades. Recent estimates indicate that over 6700 MWe (megawatts electrical) and 8200 MWt (megawatts thermal) are currently developed throughout the world. This paper discusses the specific environmental advantages to the development of geothermal electrical power and direct use projects and demonstrates how environmental impacts can be easily mitigated using existing technologies. In the areas of CO2| NOx| and SO2 emissions| land disturbance per MWe and disposal of waste products| geothermal energy has significantly fewer impacts than most other energy sources| particularly conventional fossil and nuclear fuels. Examples are sited where geothermal developments have occurred in pristine areas with no significant impacts and even offering the opportunity for improving environmental conditions. There is a strong need for energy policy makers throughout the world to recognize the environmental advantages of geothermal energy and to incorporate their economic value when pricing and selecting new sources of energy. Copyright (C) 1996 Published by Elsevier Science Ltd. 4792,1997,2,4,Environmental factors affecting migration of the European eel in the Rivers Severn and Avon| England,Studies were conducted during 1991-1993 on environmental factors affecting the upstream migration of eels in the Rivers Severn and Avon| England. Migrants (>156 000 pigmented elvers and >189 000 juveniles) were trapped as they attempted to ascend weir or sluice barriers. Multiple regression models were developed to compare catches per trap per night (C) with data for various key environmental parameters at seven sites| from the tidal limit to a maximum of 42.5 km upstream. The key stimulus for migration of both elvers and juveniles at the tidal limit was water temperature| with some weaker monthly influences related to seasonal temperature increases. Smaller annual influences probably related to earlier glass eel recruitment into the lower estuary. A weak early tidal effect was demonstrated only once| in 1993 in the Severn. Temperature also exerted significant effects on C of juvenile eels at the tidal limit and in the non-tidal rivers| although effects weakened with distance upstream. Year| month| river flows and whether traps were mounted on weirs or sluices made only small contributions at a few sites. Distance between traps also contributed to combined data for upper Severn sites. The threshold temperature in all cases was 14-16 degrees C| with low to zero catches below 10-11 degrees C| catch maxima being achieved above 18-20 degrees C. The implications of strong temperature-dependence of migration in relation to stock recruitment and management are discussed. Special reference is made to recent decreases in recruitment of eels to Europe and N. America and possible long-term effects of global warming. (C) 1997 The Fisheries Society of the British Isles. 4872,1997,3,4,Environmental impact considerations in the optimal design and scheduling of batch processes,A systematic methodology for incorporating ecological considerations in the optimal design and scheduling of batch/semi-continuous processes is presented in this paper. The methodology embeds principles from Life Cycle Analysis (LCA) within a general multi-objective formulation for the design of multipurpose batch plants| with process economics and environmental impact as distinct design objectives. An expanded boundary is defined around the process of interest| for the consistent evaluation of environmental impact| which is quantified by a set of metrics (for air| water pollution| global warming etc.). Examples from the dairy industry are presented to demonstrate the potential of the methodology to assist in arriving at environmentally friendly and economically favourable batch designs and schedules. Issues regarding the use of alternative cleaning and legislation policies on batch operation and design are also discussed. (C) 1997 Elsevier Science Ltd. 4873,1997,3,4,Environmental services as a strategy for sustainable development in rural Amazonia,Rural Amazonians| especially Indians| extractivists and other forest dwellers| desperately need something that they can sell. Sale of material commodities taken from the rainforest is the focus of most attempts to encourage 'sustainable development' for these populations| but the mother lode waiting to be tapped is not a material commodity| but rather the forest's environmental services. Converting services like biodiversity maintenance| carbon storage and water cycling into monetary flows that can support a population of forest guardians requires crossing a series of hurdles. Reliable quantification of the magnitude of services being offered is a first necessity. How to convert forest environmental services into an income stream| and how to convert this stream into a foundation for sustainable development in rural Amazonia is a great challenge. Effort should be focused on tapping environmental services as a long-term strategy for maintaining both rainforest and its population. In addition to progressing toward long-term goals| immediate measures are needed to support the population and to avoid further loss of forest. 4726,1997,3,3,Estimate of methane emissions from the US natural gas industry,Global methane emissions from the fossil fuel industries have been poorly quantified and| in many cases| emissions are not well-known even at the country level. Historically| methane emissions from the U.S. gas industry have been based on sparse data| incorrect assumptions| or both. As a result| the estimate of the contribution these emissions make to the global methane inventory could be inaccurate. For this reason the assertion that global warming could be reduced by replacing coal and oil fuels with natural gas could not be defended. A recently completed| multi year study conducted by the U.S. Environmental Protection Agency's Office of Research and Development and the Gas Research Institute had the objective of determining methane emissions from the U.S. gas industry with an accuracy of +/- 0.5% of production. The study concluded that| in the 1992 base year| methane emissions from the industry were 314 +/- 105 Bscf or 6.04 +/- 2.01 Tg (all conversions to international units are made at 15.56 degrees C and 101.325 kPa). Published by Elsevier Science Ltd. 2440,1997,4,4,Estimation and use of a multivariate parametric model for simulating heteroskedastic| correlated| nonnormal random variables: The case of corn belt corn| soybean| and wheat yields,This study develops a multivariate| nonnormal density function that can accurately and separately account for skewness| kurtosis| heteroskedasticity| and the correlation among the random variables of interest. The statistical attributes of the underlying random variables and correlation processes are examined. The potential applications of this modeling tool are discussed and exemplified by analyzing and simulating Corn Belt corn| soybean| and wheat yields. While corn and soybean yields are found to be skewed and kurtotic and exhibit different variances through time| wheat yields appear normal but also heteroskedastic. A strong correlation is detected between corn and soybean yields. 4816,1997,4,4,Estimation of the global warming trend by wavelet analysis,The self-similar (scaling) structure of temporal oscillations of the annual mean global surface air temperature during 1854-1990 is studied by wavelet analysis| These oscillations are divided into a statistically stationary part with atypical variation of about 0.5 degrees C/10 years and a trend of global warming with an increment of 0.58-0.69 degrees C/100 years. The trend has been found since 1900. Separate extrapolations of the oscillatory part and the trend at the end of the 20th century indicate that further growth of the global surface air temperature will possibly be checked. 2399,1997,2,4,Evaporation components of a boreal forest: Variations during the growing season,To improve the understanding of interactions between the boreal forest and the climate system as a key issue for global climate change| the water budget of a mixed pine and spruce forest in central Sweden was estimated by measurements of the water flux components and the total evaporation flux during the period 16 May-31 October 1995. Total evaporation was measured using eddy correlation and the components were obtained using measurements of precipitation| throughfall| tree transpiration| and forest floor evaporation| On a daily basis| tree transpiration was the dominant evaporation component during the vegetation period. However| it could be efficiently blocked by a wet canopy associated with large interception evaporation. The accumulated total evaporation was 399 mm| transpiration was 243 mm| forest float evaporation was 56 mm and interception evaporation was 74 mm| The accumulated sum of interception| transpiration| and floor evaporation was 51 mm larger than the actual measured total evaporation. This difference was mainly attributed to the fact that transpiration was measured in a rather dense 50-year-old stand while total evaporation represented the average conditions of older| roughly 100-year-old stands. To compare eddy-correlation measurements with small-scale measurements of evaporation components| a source area analysis was made to select the flux data that give the best representation of the investigated stand. Especially under stable atmospheric conditions the requirements for surface homogeneity were very high and extreme care had to be taken to be aware of the flux source areas. Canopy water storage was determined by two methods: by the water balance of the canopy| which gave a result of 3.3 mm; and by the so-called minimum method based on plots of throughfall versus precipitation| which gave a much lower value of 1.5 mm. Seasonal interception evaporation constituted 30% of the precipitation. (C) 1997 Elsevier Science B.V. 2386,1997,2,4,Experimental manipulations of snow-depth: effects on nutrient content of caribou forage,We investigated the potential effects of global climate change on arctic tundra vegetation used as caribou forage. A total of 96 experimental plots was established at six sites on the coastal plain of the Arctic National Wildlife Refuge| Alaska| in 1993 and 1994. We erected snow-fences to increase the amount of snow deposition| and therefore delay the date of the snowmelt on 48 plots (referred to as increased snow/late melting plots). We used black mesh netting on the surface of the snow to increase the rate of melting on 24 plots; the remaining 24 plots served as controls. In July 1994| we collected green leaves from Eriophorum vaginatum| Salix planifolia| and Betula nana and analysed these samples for total carbon and total nitrogen content. Ratios of carbon to nitrogen differed among treatments for all three species. Generally C:N ratios for B. nana and E. vaginatum on increased snow/late melting plots were lower than on control plots. C:N ratios for S. planifolia on increased snow/late melting plots did not differ from controls| but were lower than on plots which started to melt early. These results may be due to the timing of nitrogen translocation from leaf and stem tissue into storage organs| or due to an increase in available nitrogen input to the system. Further sampling is needed to adequately determine the mechanism responsible for increased nitrogen content of caribou forage in areas with increased amount of snow and delayed snowmelt. 4831,1997,2,3,Experimentally increased soil temperature causes release of nitrogen at a boreal forest catchment in southern Norway,Boreal forest ecosystems are sensitive to global warming| caused by increasing emissions of CO2 and other greenhouse gases. Assessment of the biological response to future climate change is based mainly on large-scale models. Whole-ecosystem experiments provide one of the few available tools by which ecosystem response can be measured and with which global models can be evaluated. Boreal ecosystem response to global change may be manifest by alterations in nitrogen (N) dynamics| as N is often the growth limiting nutrient. The CLIMEX (Climate Change Experiment) project entails catchment-scale manipulations of CO2 (to 560 ppmv) and temperature (by + 3 to + 5 degrees C) to whole forest ecosystems in southern Norway. Soil temperature is increased at 400-m(2) EGIL catchment by means of electric cables placed on the soil surface. Soil warming at EGIL catchment caused an increase in nitrate and ammonium concentrations in runoff in the first year of treatment. We hypothesize that higher temperature increased N release by mineralization. Whether these responses are only transient will be shown by additional years' treatment. 4871,1997,3,4,External costs - What do they mean for energy policy?,The European Commission's ExternE Project has made major advances in the quantification of external costs of electricity| Although some impacts cannot be valued| important conclusions are possible| This paper outlines some provisional implications for energy policy| External costs are technology dependent and for some older power plants are large compared to electricity prices| Global warming and nuclear accidents have very uncertain external costs and pose threats to sustainability. Well located renewable energy sources have low external costs and provide sustainable energy options| Both economic and regulatory instruments may be used for internalizing environmental externalities - a mix will be most appropriate. Copyright (C) 1997 Elsevier Science Ltd. 4757,1997,2,3,Farming: Closing the cycle,The natural cycle of plant and animal life involves recycling materials through the open environment. Thus carbon dioxide and many waste substances are released to the soil or atmosphere and returned to be taken up by plants. Modern agriculture has intensified the production of many substances| with unwanted effects on the atmosphere (including global warming and acid rain)| water and soil. Moreover| because most drops are grown as monoculture| competing plants| and pests and diseases| are controlled through a wide range of agrochemicals which also affect the environment; herbicides remain a major case of drinking water failing to meet the required standards. A 'clean technology' approach is urgently needed| and current research is showing the way. Research on the nitrogen cycle indicates| for example| that nitrogen losses from intensive dairy production can be reduced by up to 70%; however| changes to the whole farm system are needed to achieve results. Both engineering and biological approaches offer ways of reducing pesticide use; we can use computer control and decision support to improve the precision with which chemicals are applied; we can seek new understanding of chemical-insect-plant interactions which allow new control techniques (such as semiochemicals| which influence insect behaviour) to be derived. Agriculture can also provide a sustainable source of clean energy and could also supply industrial products such as oils and fibres| reducing our dependence on petrochemicals. 2422,1997,4,4,Formation and accumulation of gas hydrate in porous media,Vast quantities of clathrate hydrate are found in the Arctic and in marine sediments along continental margins. The clathrate structure traps enormous volumes of methane gas| which is both a possible source of global climate change and a potential energy resource. The growth rate and spatial distribution of gas hydrate in the shallow sediments are influenced by a variety of interacting physical processes. In order to quantify these processes| we develop mathematical models for hydrate formation in porous media. An analytical model is derived for the idealized problem of hydrate growth in a porous half-space which is cooled on its boundary. Our calculations predict the growth rate of a hydrate layer for a given rate of cooling and show that the volume of hydrate is strongly dependent on the two-phase equilibrium between hydrate and seawater. For a representative phase diagram we find that the volume of hydrate in the layer is less than 1% of the pore volume. Larger volumes of hydrate observed in some locations demand a sustained supply of gas and a long accumulation time. Numerical calculations are used to investigate situations that are more representative of conditions in marine sediments. A simple theoretical expression is derived for the rate of hydrate accumulation due to advection of methane gas from depth. Using typical estimates of fluid velocities in accretionary environments| we obtain an accumulation rate of 1% of the pore volume in 10(5) years. The predicted vertical distribution of hydrate is consistent with geophysical inferences from observed hydrate occurrences along the Cascadia margin. Similar distributions can arise from the combined effects of in situ methane production and warming due to ongoing sedimentation. Predicted differences between these two formation models may be detectable in geophysical and geochemical measurements. 2441,1997,4,4,From Arrhenius to megascience: Interplay between science and public decisionmaking,The life and work of Svante Arrhenius provides an interesting window on changes in the role of science in society. One hundred years ago| Arrhenius too served as science adviser to government| and he emphasized the importance of internationalism. World War I ruptured the social relations of science| and marked the beginning of a complex intertwining of research with the realm of politics. This paper considers Arrhenius' response to this trend| and asks what he would have thought of today's situation when climatology has become a megascience. Some hints of a possible answer are given against the background of a review of Arrhenius' ideas on method| and his Darwinian perspective on the growth of scientific knowledge. In the course of this| the author makes some observations on how policy determination of scientific agendas introduces an organized social dimension| where the drive for consensus may contradict the traditional ideal of a ''Darwinian struggle of hypotheses''| Arrhenius advocated. At the same time it is noted how the traditional ideal of science as neutral ''truth speaking to power'' is constantly being resuscitated| among others by the leading echelon of the Intergovernmental Panel on Climate Change (IPCC). It is suggested that the social dynamics of global-climate-change-science (or ''greenhouse research'') may be understood in terms of a model of mutually reinforcing credibility cycles| linking science and politics. 2410,1997,5,3,Gases in ice cores,Air trapped in glacial ice offers a means of reconstructing variations in the concentrations of atmospheric gases over time scales ranging from anthropogenic (last 200 yr) to glacial/interglacial (hundreds of thousands of years)| In this paper| we review the glaciological processes by which air is trapped in the ice and discuss processes that fractionate gases in ice cores relative to the contemporaneous atmosphere| We then summarize concentration-time records for CO2 and CH4 over the last 200 yr| Finally| we summarize concentration-time records for CO2 and CH4 during the last two glacial-interglacial cycles| and their relation to records of global climate change. 2411,1997,2,4,Geochemistry of corals: Proxies of past ocean chemistry| ocean circulation| and climate,This paper presents a discussion of the status of the field of coral geochemistry as it relates to the recovery of past records of ocean chemistry| ocean circulation| and climate| The first part is a brief review of coral biology| density banding| and other important factors involved in understanding corals as proxies of environmental variables| The second part is a synthesis of the information available to date on extracting records of the carbon cycle and climate change| II is clear from these proxy records that decade time-scale variability of mixing processes in the oceans is a dominant signal| That Western and Eastern tropical Pacific El Nino-Southern Oscillation (ENSO) records differ is an important piece of the puzzle for understanding regional and global climate change| Input of anthropogenic CO2 to the oceans as observed by C-13 and C-14 isotopes in corals is partially obscured by natural variability| Nonetheless| the general trend over time toward lower delta(18)O values at numerous sites in the world's tropical oceans suggests a gradual warming and/or freshening of the surface ocean over the past century. 2436,1997,4,4,Geographic information systems and the distribution of Schistosoma mansoni in the Nile delta,New computer-based sensor technology and geographic methods have led to emerging interest in use of satellite environmental assessment tools for design of disease control programs| especially for those that are vector borne. The long-range goal of work reported here by John Malone and colleagues on behalf of this Egyptian Ministry of Health-USAID Schistosomiasis Research Project team (Box 1) is to utilize data from sensor systems on board earth-observing satellites to develop more-sensitive disease-prediction and -control models. If successful| methods developed may provide a potentially vital capability for use by disease control program managers| particularly in less-developed countries| where mapping resources ave not well advanced. Longer term| broader basic questions on the interaction of environment and disease in anticipation of predicted global climate change may be addressed. These studies focused on the lower Nile river basin of Egypt The specific objective wits to link data on environmental requirements for propagation and transmission of schistosomiasis with parameters measurable from space. 4745,1997,2,4,GIS assessment of the vulnerability of the Rosetta area| Egypt to impacts of sea rise,A study of the area| including Rosetta city and the estuary of the river Nile (Rosetta branch)| has been carried out for assessment of the impact of sea level rise (sir). A geographic information system (GIS) has been built including layers of land use| topography| archeological sites| land cover and population. Analysis of data has been carried out to assess vulnerability of various land use and land cover classes to the impact of sea level rise. Because the area under study has geomorphic relief profiles just over the sea level| inundation of total land could reach 26% of total study area due to only half a meter rise in sea level. This lost area includes 32% of urban clusters mainly used for human shelter and contains 52% of present monuments| 25% of valuable high quality dense palm trees cultivation| 75% of beaches and 19% of lands suitable| 25% of valuable high quality dense palm trees cultivation| 75% of beaches and 19% of lands suitable for agricultural reclamation (although suffering from salt water intrusion and soil salinization). This is expected to cause a significant impact on the present population| economic activities| total regional revenue| and also on tourism. At 1.1 m sea level rise| 72% to total study area could be inundated. This area contains all beaches| half of the palm cultivation| 43% of total urban clusters| which includes 81% of the monumental sites and historic buildings. Other environmental problems such as solid waste management| sanitary disposal network| deteriorating conditions of some monumental structures| in addition to the sea level rise act negatively on the environmental quality of the urban community. Future plans for urban expansion in the area must be studied carefully in order to preserve valuable palm lands and maintain and protect monuments and historic sites which help the promotion of tourism. An environmental management program is essential for upgrading tourism| promoting urban development and protecting coastal lands. 4837,1997,3,3,GLAD: A gas-lift method for CO2 disposal into the ocean,To mitigate global warming| we have proposed the GLAD (Gas-Lift Advanced Dissolution) system for CO2 release into deep seawater. It is an inverse-J pipeline set in the sea at a depth of 200-400m. CO2 bubbles injected into the pipe form a buoyant plume and dissolve into the seawater as they rise. This dense solution is released from the other side of the pipe. The feasibility of our method has been examined by the numerical simulation of gas-liquid| two-phase flow with a CO2 dissolution model. In the present paper| the performance and cost of the GLAD system are discussed based on a model plant. 2427,1997,3,3,Global climate change adaptation: Examples from Russian boreal forests,The Russian Federation contains approximately 20% of the world's timber resources and more than half of all boreal forests. These forests play a prominent role in environmental protection and economic development at global| national| and local levels| as well as| provide commodities for indigenous people and habitat for a variety of plant and animal species. The response and feedbacks of Russian boreal forests to projected global climate change are expected to be profound. Large shifts in the distribution (up to 19% area reduction) and productivity of boreal forests are implied by scenarios of General Circulation Models (GCMs)| Uncertainty regarding the potential distribution and productivity of future boreal forests complicates the development of adaptation strategies for forest establishment| management| harvesting and wood processing. Although a low potential exists for rapid natural adaptation of long lived| complex boreal forests| recent analyses suggest Russian forest management and utilization strategies should be field tested to assess their potential to assist boreal forests in adaptation to a changing global environment. Current understanding of the vulnerability of Russian forest resources to projected climate change is discussed and examples of possible adaptation measures for Russian forests are presented| including: (1) artificial forestation techniques that can be applied with the advent of failed natural regeneration and to facilitate forest migration northward; (2) silvicultural measures that can influence the species mix to maintain productivity under future climates; (3) identifying forests at risk and developing special management adaptation measures for them; (4) alternative processing and uses of wood and non-wood products from future forests; and (5) potential future infrastructure and transport systems that can be employed as boreal forests shift northward into melting permafrost zones. Current infrastructure and technology can be employed to help Russian boreal forests adapt to projected global environmental change| however many current forest management practices may have to be modified. Application of this technical knowledge can help policymakers identify priorities for climate change adaptation. 2412,1997,2,4,Global climate change and natural-area protection: Management responses and research directions,During the past decade| our understanding of the potential risks that climate change poses to ecosystem function and natural-area protection has increased. Simulation studies of expected changes in species ranges and changes in ecosystem dynamics have indicated that rapidly changing climatic conditions could significantly thwart natural-area protection efforts at a global scale. In response to this potential threat| prescriptive policy and management recommendations have begun to emerge. These management responses include general guidelines for selecting new protected habitats| preemptive actions such as the development of connective corridor systems between protected areas| and active habitat management interventions. At present| many suggested natural-area management responses are only vaguely defined and have yet to be fully tested. To be effective| management responses must now be rigorously assessed with focused and practical ecological analysis. In this overview I examine the current state of research on the risks posed to natural-area protection by climate change and the feasibility of suggested management responses. Examples of potential impacts on global nature-reserve systems| the composition of landscape boundaries of natural ecosystems| and latitudinal differences in expected ecosystem response are presented to illustrate the complexity of potential habitat changes. Examples of potential nature-reserve impacts are provided to demonstrate that the spatial variation presented in climate-change scenarios significantly affects the distribution of climatic impacts on areas of biodiversity protection. An assessment of the composition of landscape boundaries of natural vegetation areas is used to demonstrate the urgent need for analysis of ecosystem dynamics in human-dominated landscapes. Changes in potential vegetation zones at different latitudes are presented to identify limitations in the use of generic rules of altitudinal species response applied globally. Ecological researchers can advance our understanding of ecosystem responses to climate change by conducting well-defined sensitivity analyses at site-specific or sub-regional scales; the current lack of fine-scale climate models need not delay such research. Direct extrapolation of observed species distributions in relation to present climate as a means for projecting future responses is inappropriate; such projections must include consideration of physiological tolerances| competition| and dispersal mechanisms. Understanding local disturbance regimes is fundamental to understanding changes in ecosystem properties and stability. How landscape fragmentation interacts with population mobility and dynamics must be defined in order to better characterize ecosystem controls. Finally| management interventions must be critically evaluated with regard to ecological viability and benefits vs. costs. 2401,1997,2,4,Global climate change and phenotypic variation among red deer cohorts,The variability of two fitness-related phenotypic traits (body weight and a mandibular skeletal ratio) was analysed among cohorts and age-classes of red deer in Norway Phenotypic variation among cohorts was pronounced for calves| yearlings and reproductively mature adults. Fluctuations in cohort-specific mean body weights and skeletal ratios of adults correlated with global climatic variation in winter conditions influenced by the North Atlantic Oscillation while cohorts were in utero. Red deer born following warm winters were smaller than those born after cold winters| and this inter-cohort variability persisted into adulthood. Phenotypic variation among cohorts of red deer influenced by climate change may pose consequences for fitness of cohorts since body size and condition contribute to reproductive success and survival in male and female red deer. In particular| the recent trend of increasingly warm winters in northern Europe and Scandinavia may lead to reduced body size and fecundity of red deer| and perhaps other ungulates| in those areas. 2419,1997,2,3,Global climate change: Processes and products - An overview,Our knowledge of global climate change has many uncertainties. Whether global air temperature will increase| by how much| and when| are subject to debate| but there is little doubt that tropospheric concentrations of several trace gases are increasing. While possible increases in the average air temperature is a product of these changes| the increases in the trace gases alone will have an effect on agriculture. Increases in the ambient concentrations of carbon dioxide are expected to have a positive net effect on crop production. In contrast| any increases in the penetration of surface-level ultraviolet-B (280-320 nm) radiation| and known increases in surface ozone concentrations| are considered to have adverse effects on certain crops. Our present knowledge of the joint effects on crops of elevated levels of carbon dioxide| ultraviolet-B radiation and ozone| and possible alterations in air temperature and precipitation patterns| is virtually zero. Therefore| any predictions of the effects of global climate change on agriculture are subject to significant uncertainties. In contrast| coupling of climate change (only temperature and precipitation) models to crop production has led to a number of future scenarios. In spite of their present limitations| results from these efforts can be useful in planning for future agriculture. 2400,1997,2,2,Global climate change: the potential effects on health,Introduction Excess carbon dioxide| methane| and other gases which trap heat are accumulating in the troposphere| the earth's lower atmosphere| because of the scale and type of human economic activity. Climate scientists predict that the resultant increase in the troposphere's "radiative forcing" will warm the earth's surface.1 2 3 Indeed| in its recent second assessment report| the Intergovernmental Panel on Climate Change-a multidisciplinary scientific body established by the United Nations in 1988 to advise governments-concluded that on balance an anthropogenic influence upon the global climate was now "discernible." 1 The intergovernmental panel forecasts an increase in the average world temperature of 1.0-3.5°C over the coming century.1 This forecast is necessarily uncertain because the sensitivity of climate to atmospheric change is imperfectly understood and because future trends in gaseous emissions and modulating processes (for example| the cooling effects of industrial aerosol emissions) cannot be foreseen accurately. Nevertheless| the expected rate of climate change over the coming century would be far greater than any natural change in world climate since the advent of agriculture 10 000 years ago. Anthropogenic climate change signifies that for the first time the aggregate global impact of humankind exceeds the physical and ecological limits of the biosphere.4 The potential consequences of this and other global changes (including stratospheric ozone depletion| loss of biodiversity| worldwide land degradation| and depletion of aquifers) are wide ranging. We can expect that climate change will affect the health and wellbeing of human populations in diverse ways. This greatly extends the temporo-spatial scale of environmental health beyond our usual concern with localised and immediate exposures to toxic or infectious agents.4 A major research task| therefore| is the application of current knowledge to forecasting probable health effects. The primary objective is to provide indicative forecasts of an important consequence that will assist pre-emptive policy making.5
4719,1997,3,2,Global energy prospects in the 21st century: a battery-based society,Current energy needs are nearly totally dependent on fossil fuels. This is causing global warming and exhaustion of resources; it is important to switch to more efficient and effective energy use. These circumstances are expanding the role of secondary batteries. Non-fossil fuels such as photovoltaic cells and wind energy are unstable| but combining them with secondary batteries improves their stability as electric power sources. If electrical load leveling between day and night can be achieved by storing electric power| it will be possible to achieve a high capacity utilization rate for generating facilities that have high generating efficiency and produce little CO2. Depending on the generating mix| the practicalization of electric vehicles will serve not only to alleviate air pollution| but also to limit CO2 emissions. There are hopes for the development of large-capacity lithium secondary batteries with long cycle life| high energy density| high power density| and high energy efficiency. (C) 1997 Elsevier Science S.A. 4694,1997,2,3,Global prediction of area change of suitable regions for cereal cultivation caused by global warming,Estimation of contemporary production regions of major cereal around the world is significant to predict food supply in the 21st century. We introduced the concept of suitable regions for cultivation. Our proposed method is to identify global suitable regions for major cereal cultivation using weather data| soil data| and vegetative biomass change patterns. We estimated the present area of suitable regions for major cereal cultivation to be 515 Mha. By comparison with the 1993 FAO statistical values| it was concluded that our method accurately identifies global suitable regions for major cereal cultivation and determines their area. Under conditions of double the current CO2 concentration| it was estimated that the area of suitable regions would be 279 Mha which represents a decrease of 46 per cent. 4712,1997,2,2,Global warming and active-layer thickness: results from transient general circulation models,The near-surface thermal regime in permafrost regions could change significantly in response to anthropogenic climate warming. Because there is only a small lag between these two processes| the impact of warming on the active layer can be investigated using relatively simple climate-driven models. A formulation attributable to Kudryavtsev was used to study the potential increase of active-layer thickness in the permafrost regions of the Northern Hemisphere| where warming is predicted to be more pronounced than elsewhere. Kudryavtsev's solution was validated using contemporary data| and successfully reproduced the actual depths of frost and thaw at widely spaced locations in North America and Eurasia. Modem climatic data and scenarios of climate change for 2050| derived from three transient coupled ocean-atmosphere general circulation models (GCMs)| were used in conjunction with the thaw-depth solution to generate hemispheric maps showing contemporary active-layer thickness for several soil types and moisture conditions| and its relative changes over the next century. The simulations indicate a 20-30% increase of active-layer thickness for most of the permafrost area in the Northern Hemisphere| with the largest relative increases concentrated in the northernmost locations. (C) 1997 Elsevier Science B.V. 4723,1997,2,4,Global warming and water management: Water allocation and project evaluation,This paper explores the sensitivity of the benefits of alternative water allocation schemes and of project evaluation to global warming. If global warming shifts the mean of annual water supplies| there could be large impacts on the expected values of alternative water allocation schemes. The first section of the paper explores how well alternative schemes (such as market mechanisms| prior rights| or percentage flows) perform if the distribution of flows changes. In a case study of the Colorado River| market mechanisms and flow guarantees result in smaller impacts than rules which allocate inefficient percentages of flows to heterogeneous users. The second part of the paper explores the effect of a gradually changing distribution of flows on project evaluations. Project evaluation is sensitive to predicted future changes in mean flows. Project evaluation is not sensitive to changes in the variance of future flows unless the variance increase is large and the benefit measure is highly curvilinear. Because basin-specific changes in runoff from global warming are currently uncertain and much delayed| most project analyses will be unaffected by global warming. The most important response by water managers to climate change may simply be to closely monitor runoff and incorporate flexible rules in order to adapt their behavior to observed changes. 4789,1997,4,4,Global warming potentials: Ambiguity or precision as an aid to policy?,It is widely assumed that the more certain and precise the scientific knowledge-base for predicting and understanding climate change| the better defined and robust will be the policy measures undertaken in response. In this paper we argue to the contrary that in the case of Global Warming Potentials (GWPs) ambiguity in their precise meaning is a major reason why they have been developed and continue as scientific policy tools [although this is not how they are commonly represented in the reports of the Intergovernmental Panel on Climate Change (IPCC)]. We survey and analyse the range of opinion on GWPs with respect to their scientific stability and comprehensiveness and argue that the utility of GWPs has to be evaluated in terms of their symbolic| interactional and heuristic effects as well as with respect to their direct instrumental uses. In addition| we argue that scientific discussion of GWPs commonly incorporates elements of the social and policy contexts of their application and provide several examples from detailed discussions at the IPCC. We endeavour to account for the ambiguous identity of GWPs and draw out several implications from the findings of the paper for the construction and use of scientific tools in policy. 2447,1997,2,4,Gradients| vegetation and climate: spatial and temporal dynamics in the Olympic mountains| USA,The steep environmental gradients of mountains result in the juxtaposition of diverse vegetation associations with narrow ecotones because life zones are compressed. Variation in geologic substrate| landforms| and soils| in combination with steep environmental gradients| create habitat diversity across spatial scales from 10(6) ha to less than 10 m(2). This leads to higher biodiversity in a smaller space than in landscapes with less topographic variation. Mountains are often considered to be refuges for biological diversity at the regional scale| although variation in landscape features creates refuges at a fine scale as well. Mountains should also be considered a source of biological diversity| because they provide the germplasm for migration into lowland areas following glacial recession. Many taxa are distributed over a broad range of elevations andhabitats| which maximizes the potential to respond to environmental perturbations. Reorganization of species distribution and abundance as a result of climatic change may be impacted considerably by human-caused fragmentation of landscape features| especially at lower elevations. This paper uses palaeoecological and biogeographical data to investigate the spatial and temporal vegetation dynamics of a steep maritime range| the Olympic Mountains (USA). The role of resource management in protecting vegetation in a fragmented landscape is discussed| with emphasis on how to address uncertainties such as climatic change.
4890,1997,3,2,Greenhouse gas chemistry,One of the major problems facing mankind is the global warming of the atmosphere due to man-made emissions of greenhouse gases. Mitigation of these greenhouse gas emissions to the atmosphere can be achieved by using direct control technologies (capture| disposal or chemical recycling). In this paper| we report on carbon dioxide and methane recycling with other chemicals| especially with hydrogen and oxygen| to produce liquid fuels such as. methanol. Methanol synthesis from pure CO2 is investigated with various catalysts at moderate pressures (less than or equal to 30 bar) and temperatures (less than or equal to 300 degrees C). The catalysts show good methanol activity and selectivity. The remarkable finding is that the equilibrium yields per pass over the catalysts are already reached at temperatures above 250 degrees C. For a stoichiometric feed| at 225 degrees C| 20 bar and at a space velocity of 4500 h(-1)| a best methanol yield equal to 7.2 % is reported. The conversion of CO2 and CH4 to methanol is also studied in a silent electrical discharge at pressures of 1 to 4 bar and temperatures close to room temperature. Methanol yields are given for mixtures of CO2/H-2| CH4/O-2 and also for CH4/air mixtures. (C) 1997 Elsevier Science Ltd. 2391,1997,3,3,Greenhouse gas emissions: Recent trends in Estonia,It is widely accepted that the increase in greenhouse gas (GHG) concentrations in the atmosphere| due to human activities| will result in warming of the Earth's surface. The worldwide project within the Framework Convention on Climate Change was generated by the initiative of United Nations| to examine this effect and better understand how the GHG increase in the atmosphere might change the climate in the future| how ecosystems and societies in different regions of the world should adapt to these changes and what must policymakers do for the mitigation of that effect. Estonia is one of more than 150 countries which signed the Framework Convention on Climate Change at the United Nations Conference on Environment and Development held in Rio de Janeiro in June 1992. in 1994| a new project| Estonian Country Study| was initiated within the U.S. Country Studies Program. The project will help to compile the GHG inventory for Estonia| investigate the impact of climate change on Estonian ecosystems| and the economy| as well as to formulate national strategies for Estonia to address global climate change. 4818,1997,3,3,Greenhouse-gas emissions from Amazonian hydroelectric reservoirs: the example of Brazil's Tucurui Dam as compared to fossil fuel alternatives,Hydroelectric dams in tropical forest areas emit carbon dioxide and methane. How these emissions and their impacts should be calculated| and how comparisons should be made with global warming contributions of alternative energy sources such as fossil fuels| can lead to sharp differences in conclusions on the relative advantages of these options. The example of Brazil's Tucurui Dam is examined to clarify these differences. The present paper ex-tends an earlier analysis to 100 years and explores the differences between these and comparable fossil fuel emissions. Factors considered here in calculating emissions for Tucurui Dam include the initial stock and distribution of carbon| decay rates and pathways (leading to carbon dioxide and methane)| and losses of power in transmission lines. Factors not considered include forest degradation on islands and reservoir shores| nitrous oxide sources in drawdown zones and transmission lines| additional methane emission pathways for release from standing trees| water passing through the turbines| etc. Construction-phase emissions are also not included; neither are emissions from deforestation by people displaced by and attracted to the project. A complete accounting of the alternative landscape is also lacking. Standardization of the level of reliability of the electricity supply is needed to compare hydroelectric and thermoelectric options. Types of emission calculations commonly used include the ultimate contribution to emissions| the annual balance of emissions in a given year| and emissions over a long time horizon (such as 100 years). The timing of emissions differs between hydroelectric and thermal generation| hydro producing a large pulse of carbon dioxide emissions in the first Sears after filling the reservoir while thermal produces a constant flux of gases in proportion to the power generated. The impacts of emissions are related to the atmospheric load (stocks) of the gases rather than to the emissions (flows)| and therefore last over a long time. According to the calculations in the present paper| the average carbon dioxide molecule in the atmospheric load contributed by Tucurui was present in the atmosphere 15 years earlier than the average molecule in the comparable load from fossil fuel generation This means that| considering a 100-year time horizon| a tonne of CO2 emitted by Tucurui has 15% more global warming impact than a tonne emitted by fossil fuel| assuming no discounting. If discounting is applied| then the relative impact of the hydroelectric option is increased. Time preference| either by discounting or by an alternative procedure| is a key factor affecting the attractiveness of hydroelectric power. At low annual discount rates (say 1-2%)| the attractiveness of Tucurui| although less than without discounting| is still 3-4 times better than fossil-fuel generation. If the discount rate reaches 15%| the situation is reversed| and fossil-fuel generation becomes more attractive from a global-warming perspective. Tucurui| with a power density (installed capacity/reservoir area) of 1.63 W m(-2) is better than both the 0.81 W m(-2) average for Brazilian Amazonia's 5500 km(2) of existing reservoirs and the 1 W m(-2) estimated by Brazil's electrical authorities as the mean for all planned hydroelectric development in the region. 4884,1997,3,4,High potential of novel zeolitic materials as catalysts for solving energy and environmental problems,Novel zeolitic catalysts have been intended to contribute syntheses of fuels and raw materials for petrochemical industry from alternative resources| and to solve environmental problems such as global warming and acid rain. While keeping an excellent pore structure of MFI zeolite| Al was successfully replaced by other transition metals by adopting the rapid crystallization method and various metallosilicate catalysts could be synthesized. H-Fe-silicate could convert light olefins totally by extraordinary high reaction rate| as high as 8 kg/l . h| into gasoline| which was composed of iso-mono-internal olefins. This gasoline fraction could be hydrogenated selectively into iso-paraffinic gasoline by using Pt catalyst supported on meso-porous silicate MCM-41 at a considerably low temperature around 150 degrees C. Ni was incorporated into the framework of SAPO-34| and this catalyst could convert methanol to ethylene with a very high selectivity of 90%. Pt-modified H-Ga-silicate and H-Zn-silicate could convert a wide range of saturated hydrocarbons into aromatics (mainly BTX) with high selectivities. Carbon dioxide was successfully converted into light olefins or gasoline using H-Fe- and H-Ga-silicate via methanol as an intermediate product. In the elimination reaction of a low concentration of NO under excess oxygen condition| various kinds of metallosilicates showed a stable activity. When the multi catalytic functions that matrix of metallosilicates| solid acid| catalytic function of metals containing in metallosilicate| kind of hydrocarbons to be added| were harmonized| NO could be effectively eliminated| and these facts could be explained by the heterogeneous reaction mechanism| Microscopic-Sequential Reaction Mechanism. H-Co-silicate exhibited much higher thermal stability than Co-ion-exchanged H-ZSM-5. The results of computer simulation to examine the thermal stability of framework| acidic properties and affinity with water supported the experimental results. 4720,1997,2,4,High temperature-induced spikelet sterility of japonica rice at flowering in relation to air temperature| humidity and wind velocity conditions,Although the impact of anticipated global warming on regional rice production merits intensive investigation| quantitative information regarding the effects of high temperatures on japonica rice is limited. The purpose of this study was to clarify the critical temperature for high temperature-induced spikelet sterility at the time of flowering in japonica rices and how it is affected by humidity and wind velocity. This research consisted of two experiments. In the first experiment| we examined the response of the varieties 'Ahihikari' and 'Koshihikari' to high temperatures at the time of flowering. Under a six-hour high-temperature treatment of panicles for eight days at flowering| the critical temperatures to induce 50% sterility were estimated to be about 36.5 degrees C for Akihikari and 38.5 degrees C for Koshihikari. The major cause of the cultivar difference was attributed to the difference in the number of pollen grains shed on stigma. In the second experiment| we examined the effects of humidity and wind velocity upon the high temperature-induced spikelet sterility of Akihikari. The fertility of spikelets flowered at 37.5 degrees C was highest at 45% relative humidity (R.H.) followed by that at 60% R.H.| and lowest at 80% R.H. Wind velocity above 0.85m s(-1) drastically decreased spikelet fertility at 37.5 degrees C| mainly through reduction of the pollen grain number shed on stigma. 4703,1997,5,4,High-resolution records of the late Paleocene thermal maximum and circum-Caribbean volcanism: Is there a causal link?,Two recently drilled Caribbean Sites contain expanded sedimentary records of the late Paleocene thermal maximum| a dramatic global warming event that occurred at ca. 55 Ma. The records document significant environmental changes| including deep-water oxygen deficiency and a mass extinction of deep-sea fauna| intertwined with evidence for a major episode of explosive volcanism. We postulate that this volcanism initiated a reordering of ocean circulation that resulted in rabid global warming and dramatic changes in the Earth's environment. 4693,1997,5,2,Holocene paleoprecipitation over the present-day Sahara desert: Implications for the future,The moderate Holocene global warming has induced a totally distinct climatic scenario over northern Africa. It is implied that the expected man-made warming will probably produce the same change in atmospheric circulation. 4778,1997,4,4,How dry is the tropical free troposphere? Implications for global warming theory,The humidity of the free troposphere is being increasingly scrutinized in climate research due to its central role in global warming theory through positive water vapor feedback. This feedback is the primary source of global warming in general circulation models (GCMs). Because the loss of infrared energy to space increases nonlinearly with decreases in relative humidity| the vast dry zones in the Tropics are of particular interest. These dry zones are nearly devoid of radiosonde stations| and most of those stations have| until recently| ignored the low humidity information from the sondes. This results in substantial uncertainty in GCM tuning and validation based on sonde data. While satellite infrared radiometers are now beginning to reveal some information about the aridity of the tropical free troposphere| the authors show that the latest microwave humidity sounder data suggests even drier conditions than have been previously reported. This underscores the importance of understanding how these low humidity levels are controlled in order to tune and validate GCMs| and to predict the magnitude of water vapor feedback and thus the magnitude of global warming. 4808,1997,2,3,Ice age initiation by an ocean-atmospheric circulation change in the Labrador Sea,The contrast between the large Greenland ice sheet and the nearly ice-free area of Canada to the west exemplifies the critical role of the moisture supply in glaciation. The trigger for new ice-sheet growth in Canada at the end of the last interglacial was probably an increase in the moisture supply rather than regional cooling. Triggering is attributed to stronger storm activity in the Labrador-Baffin area| caused by warming in the Labrador Sea and cooling in the Greenland-Norwegian Sea. The key to this temperature and circulation change may have been an increase in the hydrologic deficit of the Mediterranean Sea| A larger hydrologic deficit would have increased Mediterranean salinity and| consequently| the volume of Mediterranean Overflow Water. A resulting increased upwelling of Mediterranean Overflow Water from the lower thermocline off Scotland would have diverted additional warm North Atlantic Drift water westward via the Irminger Current| thus warming the Labrador Sea. The underlying cause of the hydrologic deficit increase was diminishing Milankovitch summer insolation in lower latitudes. This reduced African monsoon intensity and Nile River discharge. In modern times nearly all Nile discharge to the Mediterranean has been lost due to irrigation practices| culminating with the completion of the Aswan High Dam in 1968. The total increase in the hydrologic deficit due to Nile discharge loss is now 8%. In the next 70-100 years the Nile loss| added to larger evaporative losses due to CO2 warming| may increase the deficit as much as 22% above the inferred deficit at the beginning of the last glaciation thus further warming the Labrador Sea. Consequently| the triggering of major ice-sheet growth in Canada similar to 100 years from now is possible. 4801,1997,2,4,Impacts of air temperature variations on the bore rice phenology in Bangladesh: Implications for irrigation requirements,Air temperature significantly affects crop phenology. Numerous experiments have shown that prevailing air temperature determines the length of crop growth stages. Irrigation field requirements depend on the length of the crop growth stages. In the present study| a physically based parametric model| YIELD| has been applied to estimate the impacts of fluctuating air temperature (due to inter-annual climatic variability and global warming) on evapotranspiration water requirements and the length of growth stages of the irrigated bore rice in Bangladesh. The YIELD model is crop specific and crop-growth-stage specific which is a compromise between area-specific regression models and complex crop growth simulation models. The model was tuned to Bangladesh's environment to represent appropriate agro-ecological conditions including soil type| depth of ground water| field size| wind regime| and percolation losses. YIELD has been validated for the length of the growth stages| length of growing season| final yield| and evapotranspiration. A baseline estimate for the bore rice phenology has been established by running the model for 12 meteorological stations located in the major rice growing regions. Based on the analysis of the past Variations of air temperature and general circulation model (GCM) predictions| ten scenarios have been created to estimate the effects of these variations on the bore rice growth stages. These applications find that the planting date plays an important role in the bore rice phenology. This effect is most noticeable during initial growth stages. This study has found a non-linear relationship between decreasing air temperature and the length of the initial growth stage and a predominantly linear relationship with other growth stages. Model applications show that an increase in air temperature will provide longer and more stable thermal conditions for bore rice maturing stage. A 5% increase and a 4% decrease in seasonal total evapotranspiration will occur under each 1 degrees cooler and warmer air temperature conditions| respectively. A rise in evapotranspiration will cause higher demands for irrigation water. Such conditions will put pressure on the current irrigation infra-structural facilities in Bangladesh and result in reduction of bore yields. Furthermore| variations in the percent of time required for the completion of different growth stages under various air temperature conditions will demand a reorganization of irrigation schedules. (C) 1997 Elsevier Science B.V. 4685,1997,2,4,Impacts of climate change on the oases of the Argentinean cordillera,Until the mid 1970s a negative trend in the river now values in the Argentinean provinces of San Juan and Mendoza (Cuyo region) was observed. The prevailing critical conditions and their economic and social impacts provide a basis for the characterization of an adverse climate change scenario for the region. The causes of the early 1970s scenario were assessed in this study in order to determine whether or not it could be related to global warming conditions. River flows are dependent on winter precipitation and on accumulated snow on the Andes cordillera. The lowest negative river flow Value observed can be explained by the behaviour of the Southern Oscillation Index (SOI) and other macroclimatic parameters| such as sea-surface temperatures (SSTs) of the Atlantic and Pacific oceans. It was observed that the SOI is the parameter most strongly correlated with river flows. The highest correlation was found for the 2.4- and 4.8-yr frequencies and the low 43-yr frequency. Consequently| the low river flow values observed during the early 1970s are considered to be related to a low-frequency minimum of the El Nino-Southern Oscillation (ENSO)| as well as to the behaviour of sea-surface temperature close to the coast of Chile. Both factors are associated with a minimum hemispheric temperature value. It is concluded that the 1960-70 drought in the eases of the cordillera was not Linked to a warm period. Therefore it is not appropriate| at least for the time being| to state that the eases will experience drought conditions under a global warming scenario with temperature increases of a few degrees. 2460,1997,4,3,Impacts of global climate change in a hydrologically vulnerable region: Challenges to South African hydrologists,South Africa is already hydrologically vulnerable and this is likely to be exacerbated by both nonpermanent ENSO-related as well as more permanently greenhouse-gas forced climate changes. Climate change effects are explained by way of the hydrological equation. This serves as a backdrop to a brief review| in a hydrological context| of projected perturbations to temperature| rainfall and potential evaporation| over southern Africa. Methodologies for simulating hydrological responses to climate change are assessed. These include more direct GCM-derived output| with some emphasis on recent advances in climatic downscaling| and the application of appropriate hydrological models for use in impact studies. Scale problems of importance to hydrologists are highlighted. Directions to which climate change-related hydrological research efforts should be expended in South Africa are summarized| before two case study simulations| one a general sensitivity study of hydrological responses to changes in rainfall over southern Africa| the other a more specific hydrological response study to the El Nino of the 1982-83 season| are presented. The article concludes with a discussion on whether or not water resources practitioners in South Africa should respond to climate change. 4862,1997,3,3,Improving energy efficiency - The cost-effective way to mitigate global warming,The growth in world population and in demand for energy worldwide| in particular in developing countries| is highlighted. The reflection on CO2 and other greenhouse gas emissions| and the subsequent effects on the shape of climatic changes| are examined. The paper then assesses the energy intensity of economies from different parts of the world| rich and poor| and demonstrates that significant savings in energy consumption can be made. Finally| the scope and means of achieving the expected improvements in energy efficiency in the different sectors of the economy (commercial and residential| industry and transportation) are discussed in detail. Examples of the energy saving technologies are presented. Copyright (C) 1996 Elsevier Science Ltd 4826,1997,4,4,Increased coastal upwelling in the California Current System,State-space statistical models are applied to long environmental time series of monthly northward wind stress| sea surface temperature (SST)| salinity (SSS)| and sea level (SL) from the west coast of North America. The models use a combination of Kalman filtering and maximum likelihood methods| which estimate a nonlinear trend| a nonstationary and nondeterministic seasonal signal| and an autoregressive term| and effectively separate the seasonal signals from the long-term trends. The seasonal series are examined for behavior consistent with increasing coastal upwelling during the spring-summer upwelling ''season|'' presumably in response to a pattern of long-term global warming. Over a region of the California Current System (CCS) where coastal upwelling is a dominant process (32-40 degrees N)| wind stress| SST| SSS| and SL all show strong evidence of a systematic intensification of upwelling during April-July. Model trend series suggest a linear tendency for increasing equatorward stress (in agreement with the seasonal tendency)| but warmer SST (opposite the seasonal and the expectation of greater upwelling). The linear tendencies of the SST and stress trends are generally an order of magnitude greater than the seasonal tendencies. Thus the long-term trend in SST masks the cooling effect of increased seasonal upwelling| and the trend in equatorward stress suggests an artificially large seasonal increase in the observed spring and summer stress. A key to identifying these patterns has been the ability to separate the long- term nonlinear trend| using the state-space models| which mask the signal of increased upwelling in the observations. 2465,1997,4,3,Incremental costs of carbon storage in forestry| bioenergy and land-use,This paper presents a comprehensive and consistent methodology to account for the incremental costs and net changes in carbon stocks for different categories of forestry and biomass energy projects. The methodology allows consistent comparisons of the costs and quantities of carbon stored in different types of projects and/or national programs| facilitating the inclusion of forestry and biomass energy projects in a possible CO2 emission reduction regime. The framework presented includes guidelines for defining a reference case against which carbon-storage projects are compared| a carbon-storage accounting method based on simple analytic techniques for one-time terrestrial sinks| an endowment approach to incremental costing| and a discussion of local benefits and risk factors. 4748,1997,3,4,Influence of CO2| SO2 and NO in flue gas on microalgae productivity,The influence of CO2| SOx| NOx and soot dust on the productivity of microalgae was considered using Nannochloropsis salina and Phaeodactylum tricornutum. Microalgae are viewed as a possible means of combeting global warming. These microalgae can be easily cultivated in a high CO2 gas concentration of 15 vol%. SO2 gas itself does not influence the growth of microalgae. However| when the SO2 concentration is high| the pH of the medium decreases and the productivity of the microalgae is Lowered. The presence of NO does not influence the growth of microalgae. NO absorbed in the medium is changed to NO2- and utilized as a nitrogen source. As for Ni and V contained in soot dust| when the dissolved concentrations of these metals in the medium exceed more than 1 and 0.1 ppm| respectively| the microalgae productivity decreases| however| under actual conditions| their concentrations are normally lower than these values. The above results obtained in a small scale test using a simulated gas were confirmed in a field test using a raceway-type reactor with actual flue gas. 4889,1997,3,2,Influence of disposal depth on the size of CO2 droplets produced from a circular orifice,Disposal of liquid| anthropogenic CO2 in intermediate-depth ocean waters has been accepted as a means to reduce atmospheric concentrations of this greenhouse species and mitigate global warming. Since the CO2-seawater system is hydrodynamically unstable| liquid CO2 effluent in the ocean will break up into droplets. This paper discusses the influence of both the discharge orifice and properties of CO2 and seawater on the size of CO2 droplets produced. It is found that the droplet size is affected strongly by disposal depth. This suggests that determination of the behavior of CO2 discharged in the ocean must consider not only the orifice configuration| but also fluid properties at the disposal site. (C) 1997 Elsevier Science Ltd. 4772,1997,4,4,Infrared radiative forcing of CFC substitutes and their atmospheric reaction products,We have employed the radiative forcing function recently computed by Pinnock et al. [1995]| in conjunction with infrared cross sections and vibrational frequencies calculated with ab initio quantum-mechanical methods| to estimate the instantaneous infrared radiative forcing terms F-tot of a number of CFC substitutes and their atmospheric reaction products. The computed quantities F-tot are compared with those obtained by Pinnock et al. [1995] employing experimental infrared spectra. In particular| Gaussian-92(TM) software has been utilized| at the MP2/6-31G** level of theory| to provide computational estimates of these quantities. Our results agree with the former| with a mean and a standard deviation of the difference of +3% and 15%| respectively. An error analysis is provided to assess the utility of the method. The capability of quantum-mechanical computational methods to explore structural trends in radiative and physicochemical properties is exploited for the molecular systems examined here. 2454,1997,2,4,Interaction between global climate change and the physiological responses of algae,The radiation climate as one essential factor influencing phytoplankton primary production will likely change in near future due to the increase of UV-A/B radiation and to stronger vertical mixing. The emission of dimethylsulphide (DMS) from dimethylsulphonium propionate (DMSP) influences the radiation climate due to its impact on cloud formation The diatom Phaeodactylum tricornutum had a high acclimation ability to radiation stress resulting in a rapid recovery from stress induced losses in photosynthetic efficiency. In this case the primary production was not strongly impaired| and UV-B impaired photosynthesis by a mechanism different from that under excess PAR. The DMSP content of Prymnesium parvum was independent of irradiance and nitrogen supply. Total DMSP production of Prymnesium| however| was closely related to the age of the cells which was reduced under high irradiance. 4785,1997,3,4,Interactions amongst policies designed to resolve individual air issues,Six air issues are currently on science and policy agendas in Canada and elsewhere. These are climate change| stratospheric ozone depletion (increased UV-B radiation)| acidic deposition| SMOG (increased ground-level ozone)| suspended particulate matter| and hazardous air pollutants. Atmospheric scientists and decision makers have largely addressed these issues individually resulting in single-issue policies. However| it is now recognized that these issues are inter-related| and they may interact to cause negative as well as some beneficial effects| not only on the state of the atmosphere but also on societal and ecological systems. This paper illustrates through several examples the atmospheric dysfunction caused by the linkages among the six air issues. It also points to potentially conflicting policies arising from the single-issue approach| and it emphasizes the need for better integration of air issues. The linkages are summarized qualitatively in Table I. 2435,1997,5,4,Interpreting environmental and biological signals from the stable carbon isotope composition of fossilized organic and inorganic carbon,Stable carbon isotope studies on marine and terrestrial organic and inorganic carbon provide a means for detecting global climate change and for reconstructing past concentrations of atmospheric CO2. Comparison between the CO2 estimates reconstructed from carbon isotope studies for the past 150 Ma show good agreement with the predictions of a long-term carbon-cycle model based on mass-balance studies. Further| the CO2 estimates from these sources over the entire Phanerozoic show agreement with the fossil record of leaf stomatal density change-a feature inversely related to the concentration of atmospheric CO2. Isotopic studies on temporal sequences of fossilized terrestrial organic matter have contributed to palaeoecological studies on shifts in the dominance of plants with the C-4 photosynthetic pathway in ecosystems and historical changes in the metabolic processes of leaves of individual species. The long-term perspective offered by these studies provides critical information for assessing the responses of biological systems to future global environmental change. 2407,1997,4,4,Intertemporal equity| discounting| and economic efficiency in water policy evaluation,This paper addresses how the inclusion of global climate change may affect the discounting procedures used to evaluate water resources programs and projects. The primary document governing water resource planning and evaluation today is the Principles and Guidelines (P&G) adopted by the Water Resource Council in 1983. The issue is whether the P&G and related planning rules needs to be revised with regard to discounting and the choice of the discount rate in response to changing conditions associated with potential climate change and in light of the chapter on intertemporal equity| discounting| and economic efficiency from the report by the IPCC (IPCC| 1996c| ch. 4). Section 2 lays out the basic methodology of cost-benefit analysis and traces the development of issues pertaining to the choice of the discount rate. It is important to consider the discount rate issue in the context of the theoretical foundations of cost-benefit analysis and in particular| the Kaldor-Hicks compensation test. Section 3 sets out what the IPCC chapter on discounting (IPCC| 1996c| ch. 4) describes as the descriptive approach versus the prescriptive approach to choosing a discount rate. It examines the rationales which economists use to support the argument that the discount rate for evaluating public projects should be lower than the marginal rate of return on private investment. It also describes the challenges that using a lower rate poses for the economic evaluation of alternative public projects including water projects. Section 4 addresses the issue of intergenerational equity as it relates to global warming and to discounting and discusses the extent to which issues of intergenerational equity can be accounted for by lowering or raising the discount rate. Section 5 discusses the importance of dynamic flexibility. Section 6 briefly addresses the question of whether the water resources planning process should extend the multiobjective framework to incorporate a full multiobjective criterion function for inclusion in a revised P&G for the future. The final section of the paper sets forth the major conclusions to be drawn from this analysis and from the chapter on intergenerational equity| discounting| and economic efficiency of the IPCC report (IPCC| 1996a ch. 4) for the planning and evaluation procedures in the P&G. Because of the complexity of the outstanding issues regarding the discount rate and of the practical difficulty of applying procedures designed to capture all of these complexities a discounting rule is proposed that this writer believes will improve the overall efficiency of water resource decisions. Whichever procedure described in this paper is finally chosen| the current discounting rule will have to be revised. 4846,1997,5,4,Iodargyrite as an indicator of arid climatic conditions and its association with gold-bearing glacial tills of the Chibougamau - Chapais area| Quebec,The Ag halide mineral| iodargyrite| together with associated minerals chlorargyrite| bromargyrite| and ''embolite''| form a group of secondary minerals that| in terrigenous supergene environments worldwide| are exclusively confined to oxidized sulfide zones formed in arid and semi-arid climates. The presence of iodargyrite in gold-bearing glacial sediments of the Chibougamau - Chapais area of Quebec (first recorded occurrence of this mineral in Canada)| together with other indicators of an arid climate| provides cogent evidence of a past arid climate in this region. These indicators include: a) the existence of a deep water table during sulfide ore oxidation of Chibougamau copper deposits| b) the abundance of ''limonite dice'' in glacial tills| indicative of the pseudomorphic replacement of pyrite grains in bedrock formations under arid conditions| c) the abundance of spongy and corroded grains of gold typical of lateritic terranes| and d) the abundance of possibly desert-derived quartzofeldspathic sand formations. The period of aridity is conjectural at this time owing to lack of definitive dating media| but the nature and preservation of weathered profiles in the region strongly suggest a period of aridity in the Tertiary. Arid climatic conditions in this region may coincide with a known global warming period in late Eocene to middle Oligocene limes| when the Earth experienced some of its warmest temperatures. However| possible Pliocene arid conditions preceding onset of glacial events cannot be ruled out. 4849,1997,3,3,Issues in evaluating the long-term global impacts of transport policy,This paper provides an overview of issues involved in evaluating the long-term impacts of transport policy. It considers the effects of global warming| and the costs and benefits of action to reduce emissions of greenhouse gases. The overall case for such action rests on the choice of discount rate. The paper considers the relative effectiveness of taxes and regulations in controlling emissions from the transport sector| and contrasts direct action on road traffic with indirect action via policies to increase travel on public transport. After a brief mention of the issue of biodiversity| the paper concludes with some reflections on the political acceptability of different policies. 4863,1997,3,2,Japanese strategy for mitigating global warming,This paper illustrates first what the government of Japan intends to do with a few official pledges on mitigating global warming| such as the action plan and the famous idea of New Earth 21 program| toward long term stabilization of CO2 concentration in the air. In practice| however| there are a number of factors which may disturb realization of the targets envisaged in these plans. Limitation to advancement of further energy conservation| not only in industrial sectors but also in other sectors where individual consumers play key roles| is certainly serious. Another crucial factor is the nuclear power. Recent accident at the experimental FBR| Monju| has influenced the public acceptance of nuclear power very seriously| and the government is now at the stage of re-designing the future scenario of nuclear power| taking into account both the opinions in favor of nuclear and those of anti-nuclear. Nevertheless most of energy experts believe that nuclear power is safe and also economical enough to be maintained for the intermediate future at least in Japan so that strong policy measures are to be introduced to improve public acceptance of nuclear power. The second pan of this paper describes the future of so called ''new energy'' which the government of Japan is eager to develop and also the limits to development of these ''new energy''. The third pat is contributed to description of R&D of long term technological options and also difficulties in realizing these options. It is also worth noting that Japan| both government and industries| has much interest in CO2 removal from flue gas of power plants and its disposal. (C) 1997 Elsevier Science Ltd. 4708,1997,3,3,Joint implementation - An effective strategy for combating global warming?,Many see the United Nations Framework Convention on Climate Change (FCCC) as the first in a series of international treaties and agreements designed to tackle the threat of global warming. Although it includes neither quantitative emissions reduction targets nor firm timetables| the convention articulates many key principles that should guide future action to reduce global emissions of greenhouse gases. In particular| the FCCC acknowledges the historical role played by industrialised countries in the buildup of greenhouse gases and the need for them to take the lead in reducing emissions. Furthermore| it commits industrialise zed countries to provide developing countries with financial and technical assistance so that they can limit the growth of their emissions. Projections show the energy sectors of developing countries expanding rapidly over the next few decades to match the pace of industrialisation. This growth will bring with it large increases in emissions of greenhouse gases if nothing is done to dramatically increase the efficiency with which energy is used and to stimulate the use of renewable energy sources. The FCCC implicitly acknowledges these projections by allowing nations that have emissions reduction commitments to implement policies and measures jointly with other parties. This approach| known as join implementation (JI)| is one component of the strategy to combat climate change. It allows countries with higher emissions reduction costs to invest in cheaper measures elsewhere. As a reward for investing| these countries will receive partial credit for any emissions reduction that is achieved.
2442,1997,5,4,Lake Bonneville fluctuations and global climate change,Lake Bonneville| the largest late Pleistocene closed-basin lake in the North American Great Basin| fluctuated widely in response to changes in climate| The geochemistry and mineralogy of endogenic calcium carbonate deposited in deep water| and stratigraphic studies of shore-zone deposits| provide evidence of millennial-scale lake-level fluctuations that had amplitudes of about 50 m between 30 and 10 ka| Falling-lake events occurred at 21| 18.5-19| 17.5| 16-15.5| 14-13| and 10 ka (radiocarbon gears) synchronously with the terminations of Heinrich events H1 and H2 and other smaller scale iceberg-rafting events (a| b| c| and Younger Dryas) in the North Atlantic Ocean| The Lake Bonneville results thus support other climate records that suggest that late Pleistocene millennial-scale climate change was global in extent. The size and shape of the Northern Hemisphere ice sheets| which determined the mean positions of storm tracks| may have been the primary control on late Pleistocene water budgets of Great Basin lakes. 2415,1997,4,4,Linking space-time scale in hydrological modelling with respect to global climate change .1. Models| model properties| and experimental design,The link between space and time scales in hydrological modelling| in most cases| is related to both the model structure and the implementation procedure| and this makes the hydrological predictions differ from one model to another. A monthly water balance (MWB) model and the snow accumulation-ablation (SAA) and soil moisture accounting (SMA) models of the US National Weather Service (US NWS) were examined and compared on a medium-sized mountainous catchment (the Mesochora catchment in Central Greece) under historical climate conditions. The analysis focused on the model time resolution| structure| input data| and calibration process. The best results were obtained from the US NWS models| which ran on smaller time increments (6 h step for the SAA model and daily step for the SMA model)| were explicitly parameterized| and for which the input data and parameter estimate procedures were more accurate. The main model evaluation criteria were the NTD efficiency measure for the 15 year study period and the comparison of the measured and predicted streamflow by the average month. The hydrological results for both models (SAA-SMA and MWB) showed small differences in the monthly runoff values and a greater interannual variability for the SAA-SMA models. The monthly soil moisture predictions by the models were different. The hydrological simulation under global climate change conditions is presented in the companion paper. 2416,1997,2,4,Linking space-time scale in hydrological modelling with respect to global climate change .2. Hydrological response for alternative climates,The variability in monthly and seasonal runoff and soil moisture has been analysed with respect to global climate change. The seasonal runoff and soil moisture for the Mesochora catchment in Central Greece were simulated using two hydrological models that were different in structure and time resolution. Variability was investigated via a monthly water balance (MWB) model which has a first-order memory and includes a rough estimation of snowmelt component| and via the coupling of the snow accumulation-ablation (SAA) conceptual model and the soil moisture accounting (SMA) conceptual model of the US National Weather Service (US NWS). The last two models operated at a 6 h and daily time step| respectively. The SMA model predicted greater interannual variability of runoff changes than did the MWB model| for all alternative climates. However| greater runoff increases in winter (by month and season) and greater decreases in summer (by month and season) were predicted by the MWB model. During the spring and autumn months the results were much more complicated. The variability of runoff changes with respect to temperature increase showed that the MWB model is less sensitive to large temperature increase than the SAA-SMA models for all precipitation climates. Whereas the SMA model soil moisture varied substantially for the alternative climates and a particular month (and season)| the MWB model soil moisture remained unaffected by any climate during winter. The soil moisture reduction predicted from the MWB model was greater than that predicted from the SMA model in late spring and summer. There was a slight reduction in the SMA model soil moisture with respect to temperature increase in winter| for all precipitation climates. During winter and August the MWB model soil moisture remained unaffected by any temperature increase| whereas during the other months the soil moisture reduction varied proportionally with respect to temperature increase for both models (SMA and MWB) and all precipitation climates. 2420,1997,2,3,Livestock management in dryland pastoral systems: Prospects and problems,Livestock production from the drylands is quite important both in terms of the volume of product produced and in respect to the number of people dependent on livestock for their livelihood. Drylands support the full spectrum of production systems from commercial ranching in Australia| western USA| Mexico| Argentina and southern Africa through various gradations of crop-livestock systems in Africa and Asia to traditional nomadic and semi-nomadic subsistence systems. Almost everywhere| livestock production is undergoing rapid change in response to political| social| economic| environmental and demographic pressures. In this paper| we will outline the characteristics of various production systems| review their prospects and identify the problems and challenges facing them. We will assess the likely impact of global climate change and of the new technologies and the new economic world order. Finally| we will try to predict what the 21st century will be like for the millions of people whose livelihoods depend on the grazing by domesticated livestock. 4874,1997,2,4,Long-term changes of seagrass beds in the Glenan Archipelago (South Brittany),Aerial photographs and in situ data of the Glenan archipelago permit the establishment of a cartography of its Zostera marina seagrass beds. Due to the exceptionally clear water| it was possible to distinguish submerged structures| such as rocks| sand dunes| maerl beds and seagrass meadows on the photographs. The distribution of Zostera meadows was incorporated into a geographical information database through scanning| and then compared with historical data. Ten aerial photographic surveys| made over a sixty-year period from 1932 to 1992 were available. The earliest of these surveys showed the seagrass beds to be in goad condition. Low cover in 1952 suggests that the Zostera meadows within the studied area were subject to severe destructions| presumably due to the ''wasting disease''| which caused a general breakdown of the North-Atlantic populations during the 1930s. During the 1970s| the distribution of Zostera beds increased; this was followed by a gradual decline during the 1980s and early 1990s. For the investigation of the environmental circumstances under which Zostera beds are fluctuating| the Glenan site is unique. This site being relatively remote from direct anthropogenic disturbances (light irradiance decline| sewage inputs)| the causes of such fluctuations during this 60-year period can be more easily identified. Z. marina is a boreal species naturally affected by climate changes and in particular by global warming| which was at a maximum during the 1940s and 1950s. Various human activities| such as scallop dredging| maerl exploitation| yachting and anchoring| should also be considered. However| these anthropogenic disturbances were of limited importance in comparison with the dramatic decline and recovery of the seagrass beds as a result of climate fluctuations. 4728,1997,2,4,Long-term variation in fire frequency and radial increment in pine from the middle taiga subzone of central Siberia,Dendrochronological methods were used to reconstruct the dynamics of fires and radial increment in pine from the region between the Kasa and Dubchesa rivers (59 degrees-61 degrees N). The data obtained were compared with long-term climatic changes in this region. It was shown that the fire frequency varied considerably in the history of the most flammable types of pine forests. Long-term variation in fire frequency negatively correlated with that in radial increment. Climatic changes favorable for pine growth also resulted in a decreased frequency of fires. The results of analysis suggest that fire frequency during global warming will be mainly determined by regional conditions (predominantly by moisture rather than temperature). 4688,1997,2,3,Maize growth: assessing the effects of global warming and CO2 fertilization with crop models,Projected future climate change scenarios derived from two General Circulation Models (GCMs): Geophysical Fluid Dynamics Laboratory (GFDL) and United Kingdom Meteorological Office (UKMO)| and two crop models: Crop Estimation through Resources and Environmental Synthesis (CERES)| and Erosion/Productivity Impact Calculator (EPIC)| were considered to assess the climate change impact on the yield and biomass of maize. Climate change scenarios included changes in temperature| precipitation and solar radiation from two GCMs interpolated to 1 degrees x1 degrees grid cells in the central Piedmont in North Carolina. Changes in mean monthly temperature and precipitation from the GCMs were used to adjust observed daily climate records from 1949-1988. There is convincing evidence that future temperature linked to global warming might be characterized by asymmetric change between daily daytime maxima and daily nighttime minima. Two hypotheses regarding how GCM temperature would alter observational record were examined. The first hypothesis assumed that daytime and nighttime warming occurs symmetrically| i.e.| maximum and minimum temperatures are raised equally. The second hypothesis assumed that nighttime minima change is three times greater than daytime maxima change and the change in mean diurnal temperature range is approximately equal to the change in daily mean temperature. For the equal day-night warming scenario| when only the effects of climate change (i.e.| changes in temperature| precipitation and solar radiation) were considered| simulations with CERES and EPIC indicated substantial losses in maize grain yield and total above ground biomass with both the GCM scenarios. For the asymmetric warming| the reduction in biomass and yield due to climate change was less than that obtained with symmetric warming. Simulated maize yield and biomass with CERES and EPIC increased when only effects due to CO2-fertilization were considered. The inclusion of CO2 fertilization effects with those due to climate change resulted in higher biomass and yield compared to values obtained with effects of climate change alone. When CERES was used with the GFDL scenario| and the effects of CO2 fertilization and the climate change were combined| no difference in simulated yield was found between the two hypotheses; only an 8% difference in aboveground biomass was found when the UKMO scenario was used. When EPIC was used| the differential day-night warming hypothesis resulted in 9-13% less reduction in biomass and yield than did the use of the equal day-night warming hypothesis. (C) 1997 Elsevier Science B.V. 4710,1997,3,4,Massic heat capacities and Joule-Thomson coefficients of CH2FCF3 (R134a) at pressures up to 30 MPa and temperatures between about 253 K and 523 K,The massic heat capacity c(p) = (partial derivative h/partial derivative T)(p) of 1|2|2|2-tetrafluoroethane (refrigerant R134a) was measured at 18 temperatures from 253 K to 523 K at pressures between 40 kPa and 30 MPa. The Joule-Thomson coefficient mu(JT) = (partial derivative T/partial derivative p)(h) Of this substance was measured al six temperatures from 333 K to 423 K at pressures up to 20 MPa. The R134a probably has no ozone depletion potential. Its global warming potential is about one-tenth of that of the refrigerant R115 (C2F5Cl) for which it can be a substitute as a working fluid in energy technologies. (C) 1997 Academic Press Limited. 4737,1997,3,4,Measured and estimated methane and carbon dioxide emissions from sawdust waste in the Tennessee Valley under alternative management strategies,Wood waste is a potential source of methane production due to its high degradable organic carbon content and an on-site storage method that is conducive to development of anaerobic conditions. Future emissions from wood waste could be even higher if waste piles must be converted to landfills by soil capping in order to comply with national criteria for solid waste disposal. In order to estimate current and potential methane emission rates a set of field and laboratory measurements were undertaken. Gas samples for analysis of methane and CO2 were collected from the surface of sawdust piles using chambers placed on the pile surface| and at depths of 1.5| 3.0 and 4.6 m using a sampling probe. Two piles in each of the following age ranges were sampled: 0-1| 1-4| 3-5| and 5-8 years. In the laboratory study| sawdust samples from the 3.0 m depth were incubated under 20% CO2 in nitrogen at 32| 40 and 48 degrees C to simulate the temperature range and anaerobic conditions occurring in typical sawdust piles. Field measurements indicated that methane comprised 20% of the biogas generated from sawdust piles. Emissions from the pile surface averaged 1.68 mg m(-2) h(-1) compared to literature estimates from landfills on the order of 0.125-125|000 mg m(-2) h(-1) (Bogner and Scott| 1995)| with the low emission rates suggesting that a large percentage of the methane produced was either oxidized or otherwise consumed before reaching the pile surface. Emissions to the atmosphere estimated from annual sawdust production in the Tennessee Valley range from 15-44 metric tons per year incubation studies indicated highest methane generation at 32 degrees C with a reduction in emissions in excess of 70% when the temperature was increased to 48 degrees C. Estimates of methane production indicate that soil capping of disposed sawdust could increase methane production by 2-2.5 times over the biodegradation lifetime of the sawdust stored on-site. Assuming the global warming potential of methane is 21 times that of CO2| combustion of wood waste rather than on-site storage or capping would provide a CO2 offset of 1.2 or 3.8 tons| respectively| for each toll of sawdust burned. (C) 1997 Published by Elsevier Science Ltd. 4743,1997,2,4,Meltwater pulses in the northern North Atlantic: retrodiction and forecast by numerical modelling,Changes in sea surface salinity| especially by sudden meltwater pulses| are the most effective process to modify the circulation in the Greenland-Iceland-Norwegian (GIN) seas. With ''Sensitivity and Circulation of the Northern North Atlantic'' (SCINNA)| a three-dimensional ocean general circulation model| several experiments addressing the possible effects of meltwater inputs of different intensities were carried out. The experiments used (a) the last glacial maximum (LGM) reconstruction based on oxygen isotopes data from sediment cores and (b) the modern conditions of the GIN seas for their initial states. Meltwater inputs from Europe as recorded during the last deglaciation succeeding the LGM change the circulation pattern drastically. These pulses can push the high-salinity inflow from the northeast Atlantic away from Europe over to the southern coast of Iceland| thus allowing the low-salinity meltwater to spread all over the GIN seas. As a result| the deepwater formation in this region can be turned off and the circulation system shifts from the normal cyclonal-antiestuarine into an anticyclonal-estuarine mode. On the contrary| meltwater pulses originating from Greenland due to global warming mainly intensify the East Greenland Current without altering the overall circulation and temperature/salinity patterns significantly because they chiefly enhance the salinity minimum off the Greenland coast. 4733,1997,3,4,Methane and nitrous oxide emissions from rice paddy fields as affected by nitrogen fertilisers and water management,Methane and N2O emissions affected by nitrogen fertilisers were measured simultaneously in rice paddy fields under intermittent irrigation in 1994. Ammonium sulphate and urea were applied at rates of 0 (control)| 100 and 300 kg N ha(-1). The results showed that CH4 emission| on the average| decreased by 42 and 60% in the ammonium sulphate treatments and 7 and 14% in the urea treatments at rates of 100 and 300 kg N ha(-1)| respectively| compared to the control. N2O emission increased significantly with the increase in the nitrogen application rate. N2O emission was higher from ammonium sulphate treatments than from the urea treatments at the same application rate. A trade-off effect between CH4 and N2O emission was clearly observed. The N2O flux was very small when the rice paddy plots were flooded| but peaked at the beginning of the disappearance of floodwater. In contrast| the CH4 flux peaked during flooding and was significantly depressed by mid-season aeration (MSA). The results suggest that it is important to evaluate the integrative effects of water management and fertiliser application for mitigating greenhouse gas emissions in order to attenuate the greenhouse effect contributed by rice paddy fields. 4845,1997,2,3,Methane clathrate outgassing and anoxic expansion in southeast Asian deeps due to global warming,Numerous marine areas in SouthEast Asia are cold and deep enough to develop stable gas hydrates of greenhouse gases methane and carbon dioxide and of reducing agents such as hydrogen sulfide| In addition many of these deeps have low oxygen values below sill depths. Warming of such waters could: (1) destabilize existing gas hydrates (clathrates) flashing them into gas and (2) reduce the oxygen capacity of waters below the sill depth. Outgassing could increase the buoyancy| producing upwelling of potentially noxious deep waters into the photic zone and even to the surface where the greeenhouse gases would be added to the atmosphere. We plotted the depth (pressure) and temperatures of Southeast Southeast Asian deep basins on a clathrate phase diagram to determine their suceptibility to outgassing and upwelling using a creditable global warming scenario. In general| most of the Indonesian basins are too cold or too deep for any pre-existing clathrates to be destabilized by perceived global warming. However| the Sulu Basin of the Philippines and the Halmahera. Basin in Indonesian waters have sill depths in the pycnocline shoal enough and temperatures warm enough potentially to support outgassing and upwelling of basin waters| if water temperatures were raised. The presence of gas hydrates has not been demonstrated in these deeps. Although generally associated with high latitudes| clathrates have been identified in tropical waters off Central America. Accordingly| the proximity of the SouthEast Asian deeps to land and their low oxygen content suggest that tropical plant debris could accumulate and provide sufficient organic matter to generate methane and/or hydrogen sulfide clathrates. Local fisheries initially could be affected adversely by upwelling of anoxic or near anoxic waters into the photic zone. However| in the long term. the anoxic effects would dissipate and the nutrients brought up by the upwelling could increase primary productivity. A major adverse affect would be the introduction of methane into the atmosphere| as that gas has about 20 times the warming potential of carbon dioxide. 4696,1997,2,4,Methane emissions from wetlands in the zone of discontinuous permafrost: Fort Simpson| Northwest Territories| Canada,We examined the influence of water table position| temperature| vegetation| and CH4 storage on CH4 flux at 22 wetland sites located in the zone of discontinuous permafrost| near Fort Simpson| Northwest Territories. Sites ranged from frozen peat plateaux and palsas with collapse scars to fens and bogs and ponds. Mean summer CH4 emissions ranged from -1.3 to 255 mg m(-2) d(-1)| and the variation among sites was best explained by mean water table position (r(2) = 0.62| n = 19). Large CH4 fluxes (>30 mg m(-2) d(-1)) and high water tables occurred in ponds and graminoid sites| whereas small fluxes (<30 mg m(-2) d(-1)) and low water tables occur in shrub and woody sites. These relationships were upheld across several northern boreal regions| based on water table depth and broad ecological criteria. CH4 turnover times were generated by comparing surficial fluxes and storage within the saturated portion of the peat profile. Graminoid sites had CH4 turnover times from 1 to 4 days| whereas shrub or woody sites had longer turnover times| ranging from weeks to years. We estimated an overall flux of similar to 18 mg m(-2) d(-1) for the landscape around Fort Simpson. This CH4 flux may increase with the onset of global warming| owing to the fragility of permafrost| resulting in the formation of collapse scars with high CH4 emission rates. 4836,1997,4,3,Mitigation of global warming under sustainability constraints,This paper deals with sustainable energy technologies under restrictions on resources and environmental impact. We have developed a database to estimate life-cycle efficiencies and greenhouse gas emissions. Next| we define sustainability limitations on resource depletion and emissions. Based on these concepts| the present world energy system is judged to be unsustainable. Mitigation measures such as disposal of CO2 and solar power generation are evaluated utilizing the concept. We show how sustainability influences the cost-effectiveness of measures taken. Copyright (C) 1996 Elsevier Science Ltd. 4714,1997,2,3,Modelling the short-term response of the Greenland ice-sheet to global warming,A two-dimensional vertically integrated ice flow model has been developed to test the importance of various processes and concepts used for the prediction of the contribution of the Greenland ice-sheet to sea-level rise over the next 350 y (short-term response). The mass balance is modelled by the degree-day method and the energy-balance method. The lithosphere is considered to respond isostatically to a point load and the time evolution of the bedrock follows from a viscous asthenosphere. According to the IPCC-IS92a scenario (with constant aerosols after 1990) the Greenland ice-sheet is likely to cause a global sea level rise of 10.4 cm by 2100 AD. It is shown| however| that the result is sensitive to precise model formulations and that simplifications as used in the sea-level projection in the IPCC-96 report yield less accurate results. Our model results indicate that| On a time scale of a hundred years| including the dynamic response of the ice-sheet yields more mass loss than the fixed response in which changes in geometry are not incorporated. It appears to be important to consider sliding| as well as the fact that climate sensitivity increases for larger perturbations. Variations in predicted sea-level change on a time scale of hundred years depend mostly on the initial state of the ice-sheet. On a time scale of a few hundred years| however| the variability in the predicted melt is dominated by the variability in the climate scenarios. 4850,1997,3,3,Motor transport| greenhouse gases and economic instruments,Motorized transport is the generator of several forms of negative externality including the uncompensated emissions of greenhouse (global warming) gases. This paper looks at some of the underlying economic issues pertaining to policy-making designed to limit the extent of these externalities. It sets out the basic nature of the problem and outlines our knowledge of the link between the physical sciences involved and the relevant economic theory. It focuses| in particular| on the strict question of quasi-internalization in the context of a global externality. 4734,1997,4,2,Multi-fingerprint detection and attribution analysis of greenhouse gas| greenhouse gas-plus-aerosol and solar forced climate change,A multi-fingerprint analysis is applied to the detection and attribution of anthropogenic climate change. While a single fingerprint is optimal for the detection of climate change| further tests of the statistical consistency of the detected climate change signal with model predictions for different candidate forcing mechanisms require the simultaneous application of several fingerprints. Model-predicted climate change signals are derived from three anthropogenic global warming simulations for the period 1880 to 2049 and two simulations forced by estimated changes in solar radiation from 1700 to 1992. In the first global warming simulation| the forcing is by greenhouse gas only| while in the remaining two simulations the direct influence of sulfate aerosols is also included. From the climate change signals of the greenhouse gas only and the average of the two greenhouse gas-plus-aerosol simulations| two optimized fingerprint patterns are derived by weighting the model-predicted climate change patterns towards low-noise directions. The optimized fingerprint patterns are then applied as a filter to the observed near-surface temperature trend patterns| yielding several detection variables. The space-time structure of natural climate variability needed to determine the optimal fingerprint pattern and the resultant signal-to-noise ratio of the detection variable is estimated from several multi-century control simulations with different CGCMs and from instrumental data over the last 136 y. Applying the combined greenhouse gas-plus-aerosol fingerprint in the same way as the greenhouse gas only fingerprint in a previous work| the recent 30-y trends (1966-1995) of annual mean near surface temperature are again found to represent a significant climate change at the 97.5% confidence level. However| using both the greenhouse gas and the combined forcing fingerprints in a two-pattern analysis| a substantially better agreement between observations and the climate model prediction is found for the combined forcing simulation. Anticipating that the influence of the aerosol forcing is strongest for longer term temperature trends in summer| application of the detection and attribution test to the latest observed 50-y trend pattern of summer temperature yielded statistical consistency with the greenhouse gas-plus-aerosol simulation with respect to both the pattern and amplitude of the signal. In contrast| the observations are inconsistent with the greenhouse-gas only climate change signal at a 95% confidence level for all estimates of climate variability. The observed trend 1943-1992 is furthermore inconsistent with a hypothesized solar radiation change alone at an estimated 90% confidence level. Thus| in contrast to the single pattern analysis| the two pattern analysis is able to discriminate between different forcing hypotheses in the observed climate change signal. The results are subject to uncertainties associated with the forcing history| which is poorly known for the solar and aerosol forcing| the possible omission of other important forcings| and inevitable model errors in the computation of the response to the forcing. Further uncertainties in the estimated significance levels arise from the use of model internal variability simulations and relatively short instrumental observations (after subtraction of an estimated greenhouse gas signal) to estimate the natural climate variability. The resulting confidence limits accordingly vary for different estimates using different variability data. Despite these uncertainties| however| we consider our results sufficiently robust to have some confidence in our finding that the observed climate change is consistent with a combined greenhouse gas and aerosol forcing| but inconsistent with greenhouse gas or solar forcing alone. 4730,1997,3,4,Nitrous oxide emissions from fertilised grassland: A 2-year study of the effects of N fertiliser form and environmental conditions,The aim was to investigate the effects of different N fertilisers on nitrous oxide (N2O) flux from agricultural grassland| with a view to suggesting fertiliser practices least likely to cause substantial N2O emissions. and to assess the influence of soil and environmental factors on the emissions. Replicate plots on a clay loam grassland were fertilised with ammonium sulphate (AS)| urea (U)| calcium nitrate (CN)| ammonium nitrate (AN)| or cattle slurry supplemented with AN on three occasions in each of 2 years. Frequent measurements were made of N2O flux and soil and environmental variables. The loss of N2O-N as a percentage of N fertiliser applied was highest from the supplemented slurry (SS) treatment and U| and lowest from AS. The temporal pattern of losses was different for the different fertilisers and between years. Losses from U were lower than those from AN and CN in the spring| but higher in the summer. The high summer fluxes were associated with high water-filled pore space (WFPS) values. Fluxes also rose steeply with temperature where WFPS or mineral N values were nor limiting. Total annual loss was higher in the 2nd year| probably because of the rainfall pattern: the percentage losses were 2.2| 1.4| 1.2| 1.1 and 0.4 from SS| U| AN| CN and AS| respectively. Application of U in the spring and AN twice in the summer in the 2nd year gave an average emission factor of 0.8% - lower than from application of either individual fertiliser. We suggest that similar varied fertilisation practices| modified according to soil and crop type and climatic conditions| might be employed to minimise N2O emissions from agricultural land. 4731,1997,3,4,Nitrous oxide emissions from grassland and spring barley| following N fertiliser application with and without nitrification inhibitors,The aims of this study were to assess the effectiveness of the nitrification inhibitors dicyandiamide (DCD) and nitrapyrin on reducing emissions of nitrous oxide (N2O) following application of NH4+ or NH4+-forming fertilisers to grassland and spring barley. DCD was applied to grassland with N fertiliser applications in April and August in 1992 and 1993| inhibiting N2O emissions by varying amounts depending on the fertiliser form and the time of application. Over periods of up to ? months following each application of DCD| emissions of N2O were reduced by 58-78% when applied with urea (U) and 41-65% when applied with ammonium sulphate (AS). Annual emissions (April to March) of N2O were reduced by up to 58% and 56% in 1992-1993 and 1993-1994| respectively. Applying DCD to ammonium nitrate (AN) fertilised grassland did not reduce emissions after the April 1993 fertilisation| but emissions following the August application were reduced. Nitrapyrin was only applied once| with the April fertiliser applications in 1992| reducing N2O emissions over the following 12 months by up to 40% when applied with U. When N fertiliser was applied in June without DCD| the DCD applied in April was still partly effective; N2O emissions were reduced 50%| 60% and 80% as effectively as the emissions following the April applications| for AS in 1993| U in 1992 and 1993| respectively. In 1992 the persistence of an inhibitory effect was greater for nitrapyrin than for DCD| increasing after the June fertiliser application as overall emissions from U increased. There was no apparent reduction in effectiveness following repeated applications of DCD over the 2 years. N2O emissions from spring barley| measured only in 1993| were lower than from grassland. DCD reduced emissions from applied U by 40% but there was no reduction with AN. The results demonstrate considerable scope for reducing emissions by applying nitrification inhibitors with NH4+ or NH4+-forming fertilisers; this is especially so for crops such as intensively managed grass where there are several applications of fertiliser nitrogen per season| as the effect. of inhibitors applied in April persists until after a second fertiliser application in June. 4725,1997,3,4,No-till farming: The way of the future for a sustainable dryland agriculture,Most dryland fanning systems depend an tillage to grow crops. There is overwhelming evidence that repeated tillage is destroying the soil resource base and causing adverse environmental impacts. Tillage degrades the fertility of soils| causes air and water pollution| intensifies drought stress| destroys wildlife habitat| wastes fuel energy| and contributes to global warming. Consequently| most tillage-based systems in a dryland environment are not sustainable in the long-term. Today| dryland farmers are expected to produce food in ever greater quantities. This is becoming more difficult to do in view of declining soil quality| most of which is caused by soil tillage. It is becoming well documented scientifically that continuous no-till is the most effective| and practical approach for restoring and improving soil quality which is vital for sustained food production and a healthy environment. With this way of farming crop| residues or other organic amendments are retained on the soil surface and sowing/fertilizing is done with minimal soil disturbance. Research and farmers' experience indicate that with continuous no-till soil organic matter increases| soil structure improves| soil erosion is controlled| and in time crop yields increase substantially from what they were under tillage management| due to improved water relations and nutrient availability. These changes help to promote a cleaner and healthier environment and a more sustainable agriculture. A major obstacle that farmers often face with change to continuous no-till is overcoming yield-limiting factors during the transition years| that is| the first years of no-till following a history of intensive conventional tillage. These factors are often poorly understood and may be biologically-driven. Some of the problems involve residue management and increased weed and disease infestations. Farmer experience seems to indicate that many problems during the transition are temporary and become less important as the no-till system matures and equilibrates. The judicious use of crop rotations| cover crops and same soil disturbance may help reduce agronomic risks during the transition years. Farmers switching to continuous no-till must often seek new knowledge and develop new skills and techniques in order to achieve success with this new and different way of farming. Answers to their questions are urgently needed to provide strategies far promoting no-till as a way to enhance agricultural sustainability for future generations. 4722,1997,2,2,Nonmarket valuation and the estimation of damages from global warming,This paper is concerned with nonmarket valuation in the context of global warming. First| concerning the impact of global warming: what are the prospects for the inclusion of nonmarket values in estimates of the damages of warming? The second question relates to the role of the Principles and Guidelines as the supporting document for water resource projects. Are tools for nonmarket valuation| as found in the Principles and Guidelines satisfactory for water resource project evaluation with a changing climate? The potential effects of climate change are so numerous and subtle that it would be prohibitively costly to measure them all. Thus a comprehensive program for including nonmarket damages as part of the costs of global warming seems ill-advised. Where specific concerns arise| researchers may learn from small scale studies. Many of the damages of global warming are diminished by the ability of humans to adapt at small costs| especially the nonuse component of nonmarket values. When the question concerns minor water resource projects| the gains from including extra effects induced by global warming seem to be small compared with the costs. The Principles and Guidelines does not reflect current practices in benefit estimation. However| it is not clear that this is a serious problem| because most practitioners continue to revise their understanding of valuation methods. If the Principles and Guidelines were to be revised| it would make sense to provide more current guidelines for all of the behavioral models and contingent valuation. Revisions of the Principles and Guidelines should not do anything special for anthropocentrically induced climate change. 4761,1997,3,3,Nuclear energy conversion systems for arresting global warming,Presently the global warming by CO2 emission from fossil fuel burning is becoming a serious issue. Especially| coal is the worse fossil fuel| because it emits the largest amount of CO2 per unit amount of heat generation. There seem to be two ways of reducing substantial CO2 emission rate of coal; they are| reforming coal to synthesis fuel with less CO2 emission and removing CO2 from hue gas of coal fired power station after burning coal. Present paper proposes two nuclear heat application systems which reform coal to methanol and four systems which produce chemical products or gasoline with CO2 collected from Rue gas of coal fired power stations| as future options for reducing CO2 emission from coal. Advantage and disadvantage of the proposed systems are discussed. (C) 1997 Elsevier Science Ltd. 4758,1997,3,4,OH reaction kinetics and atmospheric impact of 1-bromopropane,The temperature-dependent rate constant for the reaction of the OH radical with 1-bromopropane has been measured using the discharge flow technique with laser-induced fluorescence detection of the OH radicals. Rate constants were measured as a function of temperature between T = 271 K and T = 363 K. The temperature dependence is well described by a simple Arrhenius expression| k(T) = A exp[-E/(RT)]. We find that A = (5.75 +/- 0.9) x 10(-12) cm(3) molecule(-1) s(-1) and E/R = 504 +/- 50 K for the OH reaction rate with CH3CH2CH2Br. The reaction rate at T = 277 K is 9.3 x 10(-13) cm(3) molecule(-1) s(-1)| which implies that the atmospheric lifetime for CH3CH2CH2Br is approximately 15 days using the scaling method of Prather and Spivakovsky. In addition| the quantitative infrared spectrum for 1-bromopropane has been obtained using a Fourier transform spectrometer. Together with the atmospheric lifetime estimate| this spectrum implies global warming potentials of 1.0| 0.3| and 0.1 for integration time horizons of 20| 100| and 500 years| respectively. We have calculated the ozone depletion potential (ODP) for bromopropane based on the kinetic results using our 2-D model and using the standard semi-empirical approach. The semiempirical calculation of the ODP| using the 15 day lifetime and the model calculated vertical profile of 1-bromopropane| gives 0.0019. However| the 2-D model result is 0.027 using a fixed mixing ratio boundary condition for 1-bromopropane. It is likely that the semiempirical method is inappropriate for species with lifetimes as short as 15 days. 4842,1997,2,3,On modification of global warming by sulfate aerosols,There is increasing evidence that the response of climate to increasing greenhouse gases may be modified by accompanying increases in sulfate aerosols. In this study| the patterns of response in the surface climatology of a coupled ocean-atmosphere general circulation model forced by increases in carbon dioxide alone is compared with those obtained by increasing carbon dioxide and aerosol forcing. The simulations are run from early industrial times using the estimated historical forcing and continued to the end of the twenty-first century assuming a nonintervention emissions scenario for greenhouse gases and aerosols. The comparison is made for the period 2030-2050 when the aerosol forcing is a maximum. In winter| the cooling due to aerosols merely tends to reduce the response to carbon dioxide| whereas in summer| it weakens the monsoon circulations and reverses some of the changes in the hydrological cycle on increasing carbon dioxide. This response is in some respects similar to that found in simulations with changed orbital parameters| as between today and the middle Holocene. The hydrological response in the palaeosimulations is supported by palaeoclimatic reconstructions. The results of changes in aerosol concentrations of the magnitude projected in the scenarios would have a major effect on regional climate| especially over Europe and Southeast Asia. 2385,1997,4,4,Opposing southern ocean climate patterns as revealed by trends in regional sea ice coverage,The 16.8 year sea ice record (November 1978 to August 1995) derived from satellite passive microwave data shows evidence of contrasting climate patterns in the Southern Ocean as indicated by persistent opposing trends in regional sea ice coverage. Southern Ocean regions adjoining the south Atlantic| south Indian and southwest Pacific Oceans show increasing trends in sea ice coverage| particularly during non-winter months| while regions adjoining the southeast Pacific Ocean show decreasing trends in sea ice coverage| particularly during summer months. The data are compiled from three successive passive microwave sensors from which two separate time-series are analyzed. The first includes the data originally released by the National Snow and Ice Data Center (NSIDC) which have not been significantly adjusted to account for differences in the successive sensors| while the second includes data recently released by NSIDC which have been rigorously adjusted (Cavalieri et al.| 1997) to account for differences between sensors. Although the significance of many of the increasing trends detected in the original time-series decrease in the reanalyzed time-series| the overall pattern of contrasting trends remains evident. These trends have important implications for the southern hemisphere heat budget and surface albedo as well as for marine ecosystems associated with various sea ice habitats. Other evidence of contrasting climate patterns with respect to southern hemisphere atmospheric circulation is explored. Due to the relatively short sea ice record| it still remains to be seen whether these trends are natural decadal variation or indicative of global climate change. However| the persistent opposition in Southern Ocean regional ice coverage is noteworthy and may well be studied using global circulation models in order to better define potential positive and negative feedbacks for global change scenarios. 4806,1997,3,3,Optimal reductions in CO2 emissions,Current optimizing climate-economy models use CO2 uptake functions that greatly underestimate both peak atmospheric CO2 concentrations and the time horizon of elevated CO2. As a result these models underestimate potential global warming damages| Here| a more realistic| but practical| carbon cycle parameterization is developed that can be incorporated within an optimizing climate-economy model framework| This method is utilized in conjunction with the DICE model (Nordhaus| 1994) to estimate optimal reductions in CO2 emissions. The results are shown to be extremely sensitive to the pure rate of time preference| rho. For rho=3% (Nordhaus' preferred value)| our model predicts an optimal CO2 emission reduction of 13% by the year 2045| as compared to 11% in the original DICE model| But| for rho=0% the optimal emissions reduction rises to 79% in the year 2045 and to 97% by the year 2200| We argue that energy policy should be guided by the rho=0% results for both economic and ethical reasons| A steady-state analysis performed using the DICE model supports the argument that large fractional reductions in CO2 emissions should be undertaken. (C) 1997 Elsevier Science Ltd. 2417,1997,4,3,Optimization of a non-linear dynamical system for global climate change,We regard the global climate system as a controlled dynamic system| with controls corresponding to economic activities causing emissions of greenhouse gases. Previous optimization studies for climate change have used descriptions of the environmental system which are found to be too unrepresentative of what is known in the scientific community| In this paper an approach is applied which tries to include a more sophisticated model of the environmental system. The resulting continuous dynamic control problem is solved by the application of a set of non-linear optimization techniques to find optimal response strategies to maximize the discounted sum of future consumption while adhering to certain environmental constraints. (C) 1997 Elsevier Science B.V. 4891,1997,3,3,Optimization of the fertilization by nutrients of the ocean| taking fixation by phytoplankton into account,Fertilization of the ocean with nutrients such as nitrate and phosphate is one of the countermeasures against the global warming problem. In the present paper| we evaluated the effective ratio of the nutrients sprinkling into the ocean to the nutrients assimilation by phytoplankton. When the nutrients equivalent to the 1/500 of the annual accumulated amount of CO2 in the atmosphere were sprinkled within the circle of 7.1 - 100 km radius by a ship| less than 0.01 % of the nutrient was found to be transferred to the deep ocean without assimilation. The rest remained in surface ocean| most of which was found to be incorporated in the phytoplankton within one year. We also evaluated the energy balance of transportation of the fertilizers by ship to that taken up by the fertilization in ocean| The energy evaluation indicated that the amount of CO2 produced from the transportation process was about 0.23 % of the amount that is expected to be taken up into the ocean from the atmosphere. Furthermore| we estimated the energy balance of fertilization with activated sludge instead of fertilizer. It was found that fertilization by activated sludge containing a great deal of water needed a large amount of energy for the transportation by ship. (C) 1997 Elsevier Science Ltd. 4848,1997,2,4,Organochlorine contamination of the Canadian Arctic| and speculation on future trends,Emission of organochlorine chemicals in urban| agricultural and industrial regions of the world has resulted in a substantial influx to the Canadian Arctic. Long-range atmospheric transport and what has been referred to as 'global distillation' transport many chemicals from warm source areas to cold| polar regions. Organochlorines are detected in Arctic air| water| and snow| with substantial accumulations in animals| marine mammals| and humans. This has led to concern regarding health effects to native people who consume traditional foods. Speculations on future trends of organochlorines in the Arctic is presented and related to global warming effects and the physical chemistry of the compounds of interest. It is conceivable that high levels of certain contaminants in the Arctic environment may persist for decades despite recent reductions in global emissions. 4830,1997,4,4,Permafrost zonation and climate change in the northern hemisphere: Results from transient general circulation models,Numerous studies have demonstrated that both global patterns and local details of permafrost distribution are highly responsive to climatic fluctuations| at several temporal and spatial scales. Permafrost currently underlies about one fourth of the land area of the northern hemisphere| and many qualitative predictions have been made for a severe reduction of this area in response to global warming. A map of permafrost distribution compiled using the 'frost index'| a dimensionless number that can be related to the zonal arrangement of permafrost| shows very good correspondence with a recently published empirical map. The frost index was used in conjunction with three transient general circulation models to compile maps of permafrost zonation for conditions in the mid-21st century. Although regional patterns and local details differ substantially between the three scenarios| all result in reductions in the area occupied by each permafrost zone. Localized expansions of the area underlain by permafrost are apparent from two of the scenarios. Reductions in the areal extent of equilibrium permafrost predicted from two of the three transient models are much less than those indicated by runs using 2 x CO models. 4838,1997,2,2,Polar snow cover changes and global warming,Many general circulation models suggest that current precipitation amounts in polar latitudes will increase under double CO2 scenarios. Even though temperatures in such high-latitude regions should also increase under a doubling of CO2| as long as those temperatures remain below freezing| the increased precipitation should accumulate as snow. A study of both current and double CO2 temperature and precipitation data for all land areas poleward of 60 degrees latitude using three different general circulation models suggests possible changes in snow accumulation due to increasing CO2. Increased snow accumulation will occur in the Antarctic whereas a small decrease in snow depth is to be expected in the Northern Hemisphere. Total snow accumulation for all land areas poleward of latitude 60 degrees is found to increase under a double CO2 scenario.
4711,1997,2,3,Possible change in climate parameters with zero net radiative forcing,There has been much debate over the possibility that radiative cooling due to anthropogenic aerosols may substantially offset global warming from the enhanced greenhouse effect of raised atmospheric carbon dioxide levels. It is accepted that regional climates may alter if the net local forcing is non-zero. However| recent studies have alluded to the possibility of climate change even when the net radiative forcing from aerosols and carbon dioxide is very small. We present calculations demonstrating that even when the net radiative forcing of climate from simultaneous aerosol and CO2 perturbations at all locations is zero| heating rates within the atmosphere and surface radiation characteristics may still be substantially altered. Given the effect of radiative heating on atmospheric motions| and the dependence of biological systems on insolation| we conclude that the effects of possible climate change even when the mean radiative forcing at all locations is unchanged need to be quantified. Although an important quantity| the radiative forcing of climate should not be used as the sole indicator of possible climate change. 4858,1997,3,4,Possible options for mitigating methane emission from rice cultivation,Studies focused on mitigating CH4 emission from rice paddy fields are summarized and the possibilities and limits that the options might be applied to world's rice cultivation are discussed. The mitigation options are water management| soil amendments| organic matter management| different tillage| rotation| and cultivar selection. Altering water management| in particular promoting midseason aeration by short-term drainage| is one of the most promising strategies| although these practices may be limited to the rice paddy fields where the irrigation system is well prepared. Improving organic matter management by promoting aerobic degradation through composting or incorporating into soil during off-season drained period is another most promising candidate. There are several formidable obstacles to adopt the mitigation options into local rice farming| including limited applicability to different types of rice fields| increasing cost and labor| negative effects on rice yield and soil fertility| and time requirement for practical application. Further studies to verify the mitigation options should focus on the feasibility for local farmers. 4771,1997,2,3,Potential effects of climate change on aquatic ecosystems of the Great Plains of North America,The Great Plains landscape is less topographically complex than most other regions within North America| but diverse aquatic ecosystems| such as playas| pothole lakes| ox-bow lakes| springs| groundwater aquifers| intermittent and ephemeral streams| as well as large rivers and wetlands| are highly dynamic and responsive to extreme climatic fluctuations. We review the evidence for climatic change that demonstrates the historical importance of extremes in north-south differences in summer temperatures and east-west differences in aridity across four large subregions. These physical driving forces alter density stratification| deoxygenation| decomposition and salinity. Biotic community composition and associated ecosystem processes of productivity and nutrient cycling respond rapidly to these climatically driven dynamics. Ecosystem processes also respond to cultural effects such as dams and diversions of water for irrigation| waste dilution and urban demands for drinking water and industrial uses. Distinguishing climatic from cultural effects in future models of aquatic ecosystem functioning will require more refinement in both climatic and economic forecasting. There is a need| for example| to predict how long-term climatic forecasts (based on both ENSO and global warming simulations) relate to the permanence and productivity of shallow water ecosystems. Aquatic ecologists| hydrologists| climatologists and geographers have much to discuss regarding the synthesis of available data and the design of future interdisciplinary research. (C) 1997 by John Wiley gi Sons| Ltd. 4790,1997,2,3,Potential effects of climatic change on radiological doses from disposal of Canadian nuclear fuel waste,The environmental assessment of deep geologic disposal of Canadian nuclear fuel waste considers many processes that could affect radionuclide transport to humans over thousands of years. Climatic change is an important feature that will occur over these long times. Glaciation will likely occur within the next 100|000 years over much of Canada| and its impact on radiological doses has been assessed previously. In the present study| we investigate the potential effect of shortterm climatic change| usually associated with global warming caused by increases in atmospheric trace gases. We study the main biosphere transport pathways causing a radiological dose to humans from I-129| which is the most important radionuclide in disposal of Canadian used nuclear fuel. Irrigation of a garden with contaminated well water is the main pathway and it can be affected by changes in temperature and precipitation. A cold| wet climate decreases the need for irrigation| and this decreases the radiological dose. A drastic climatic change| such as an increase in temperature from 10 to 20 degrees C and decrease in precipitation from 0.3 to 0.2 m during the growing season| is estimated to increase the dose by a factor of four. This is a relatively small change compared to the range of doses that arise from the variability and uncertainty in many of the parameters used in the environmental assessment models. Therefore| it is likely that the results of probabilistic dose assessment models can include the consequences of short-term climatic change. 2389,1997,4,4,Predicting high-risk years for malaria in Colombia using parameters of El Nino southern oscillation,The interannual variation in malaria cases in Colombia between 1960 and 1992 shows a close association with a periodic climatic phenomenon known as El Nino Southern Oscillation (ENSO). Compared with other years| malaria cases increased by 17.3% during a Nino year and by 35.1% in the post-Nino year. The annual total number of malaria cases is also strongly correlated (r = 0.62| P < 0.001) with sea surface temperature (SST) anomalies in the eastern equatorial Pacific| a principal parameter of ENSO. The strong relation between malaria and ENSO in Colombia can be used to predict high and low-risk years for malaria with sufficient time to mobilize resources to reduce the impact of epidemics. In view of the current El Nino conditions| we anticipate an increase in malaria cases in Colombia in 1998. Further studies to elucidate the mechanisms which underlie the association are required. As Colombia has a wide range of climatic conditions| regional studies relating climate and vector ecology to malaria incidence may further improve an ENDO-based early warning system. Predicting malaria risk associated with ENSO and related climate variables may also serve as a short-term analogue for predicting longer-term effects posed by global climate change. 4854,1997,2,4,Preliminary climatology of southern Africa extreme weather: 1973-1992,Preliminary climatological statistics of extreme weather events over the southern Africa region are established through analysis of daily weather maps of the South African Weather Bureau for a twenty year period| 1973-1992. Influences of global warming and inter-annual variability imposed by El Nino events| amongst others| are sought. Notable trends include a decrease in the frequency of station days with rainfall > 70 mm and an increase in station days with temperature > 38 degrees C. Correlations offer some insights to extreme climate associations. Lows over the land in the west and over the sea to the east display consistent interannual variability| despite opposing rainfall regimes. Agreement in extreme temperature statistics in all regions suggest that drought is widespread over southern Africa. Rainfall in the north is negatively related to lows over the sea to the south. A potential mechanism underlying the inverse relationship between midlatitude and sub-tropical storminess is the development of a vorticity dipole associated with the westerly jet stream. This is investigated in an El Nino-influenced case study. 4795,1997,4,4,Pressure effect of sound speed in the deep ocean,Recently| ocean acoustic tomography (OAT) has been used to investigate the phenomenon of global warming and for wide area oceanic observation. This research requires one to correctly determine the sound speed from the sea surface to the bathyal zone. The calculation of sound speed is primarily based on the equation for the speed of sound determined by Del Grosso and Chen and Millero. There are many discussions with respect to the differences between the equation for sound speed by Chen and Millero and that by Del Grosso. We measured data of temperature| salinity| pressure and sound speed from the sea surface to the bathyal zone in detail using the deep submergence vehicle| ''SHINKAI 6500|'' from the Japan Marine Science and Technology Center (JAMSTEC). From our measurements| the constant term of the gradient of sound speed from the measured data agrees with that of the equation derived by Chen and Millero| while the first and the second terms of the gradient of sound speed from the measured data agree with that of the equation by Del Grosso. 2433,1997,4,4,Problems associated with homogeneity testing in climate variation studies: A case study of temperature in the northern Great Plains| USA,Global climate change is a controversial issue facing researchers and climatologists today. In order to obtain the most reliable results when studying climate change| the data being analysed must be as homogeneous as possible. A homogeneous time series is one in which trends and variations are caused only by effects of weather and macroclimate. The concept of homogeneity has been addressed by some researchers| but only by testing 'average' time series such as the means and the annuals. This paper utilizes a homogeneity test developed by Alexandersson and applies it to mean monthly maximum| minimum| and mean temperature data from 22 stations in the northern Great Plains| USA. One of these| Valentine| is a first-order station and is used as the reference station. When Valentine was adjusted for a possible inhomogeneity due to its move| it was found that Valentine's adjustments had a distinct seasonal pattern. After testing the other stations against Valentine| it was found that the position of a significant discontinuity in a station's monthly mean or annual series was not always the same in a corresponding monthly maximum and minimum series. In addition| a seasonal pattern similar to that of Valentine was found for each station's adjustment values. (C) 1997 the Royal Meteorological Society. 4864,1997,3,3,Progress on binding CO2 in mineral substrates,Based on current estimates of reserves| coal could satisfy even a very much increased world energy demand for centuries| if only the emission of CO2 into the atmosphere could be curtailed. Here we present a method of CO2 disposal that is based on combining CO2 chemically with abundant raw materials to form stable carbonate minerals. A major advantage of this method is that the resulting waste product is thermodynamically stable and environmentally neutral. It is therefore possible to store large quantities permanently with minimal environmental impact and without the danger of an accidental release of CO2 which has proven fatal in quantities far smaller than contemplated here. The raw materials to bind CO2 exist in nature in large quantities in ultramafic rocks. They are readily accessible and far exceed what would be required to bind all CO2 that could possibly be generated by burning the entire fossil fuel reserves. In this paper we outline a specific process that we are currently investigating. Our initial rough cost estimate of about 3 cent/kWh is encouraging. The availability of a CO2 fixation technology would serve as insurance in case global warming| or the perception of global warming. would cause severe restrictions on CO2 emissions. If the increased energy demand of a growing world population is to be satisfied from coal| the implementation of such a technology would be unavoidable. Published by Elsevier Science Ltd. 2453,1997,5,4,Quaternary sea level variations in the Pacific-Indian ocean gateways: Response and impact,The Indonesian Maritime Island| also called the Maritime Continent| is situated in a unique geographic setting relating to regional and global climate change. Tropical monsoons| between Asia and Australia| exert a strong influence on this area. Pacific and Indian Ocean currents pass through the island corridors and rise to the Sunda-Sahul epicontinental platforms bringing nutrients that support reef development. This system may be disturbed during glacial low sea level. However| the deep passage Indian-Pacific Ocean gateways remained open during glaciations allowing deep ocean currents to continue flowing between the emerged Sunda and Sahul platforms. Thus| the coastal plain of the large lowland area| and the large| shallow and stable Sunda-Sahul platforms are sensitive to eustatic sea level changes. Changes in basin volume| in the long term| may be the primary control on global sea level but in the relatively short term global climate change could be the most significant cause of sea level oscillations. Based on a study of uplifted coral reefs| an Upper Pleistocene sea level curve has been constructed for the Indonesian region. This curve had been corrected by using Oxygen Isotope data from ODP Hole 677. Copyright (C) 1996 INQUA/Elsevier Science Ltd 4773,1997,4,3,Radiative forcing calculations for CH3Cl and CH3Br,Methyl chloride| CH3Cl| and methyl bromide| CH3Br| are particularly important in the global atmosphere as major natural sources of chlorine and bromine to the stratosphere. The production of these gases is dominated by natural sources| but smaller| important anthropogenic sources| such as agricultural fumigation and/or biomass burning| also exist. As absorbers of infrared radiation these gases are of interest for their potential effect on the tropospheric energy balance as well as for chemical interactions. In this study we estimate the radiative forcing and Global Warming Potentials (GWPs) of CH3Cl and CH3Br. Our calculations use an infrared radiative transfer model based on the correlated k-distribution algorithm for band absorption. Radiative forcing values of 0.0047 W/m(2) per part per billion by volume (ppbv) for CH3Cl in the troposphere and 0.0049 W/m(2) per ppbv for CH3Br in the troposphere were obtained. On a per molecule basis the radiative forcing values are about 2% of the forcing of CFC II and about 270 times the forcing of CO2. GWPs for these gases are about 8 for CH3Cl and about 4 for CH3Br (100 year time integration| CO2 = 1). These results indicate that while CH3Cl and CH3Br have direct GWPs similar to that of CH4| the current emission rates are too low to contribute meaningfully to atmospheric greenhouse heating effects. 4740,1997,3,3,Radiative forcing of climate change by CFC-11 and possible CFC-replacements,The infrared absorption cross sections of CFC-11 and 16 other halogenated compounds have been measured. These spectra were used in detailed line-by-line calculations to derive radiative forcing values. The radiative forcing values for 14 of these gases have not| to our knowledge| been previously reported in the literature. The accuracy of a computationally inexpensive narrowband scheme| which included the effect of clouds and stratospheric adjustment| was investigated. Global warming potentials are presented where atmospheric lifetimes are available. In light of the substantial disagreement in values for the forcing due to CFC-11 reported in the literature and its use as a standard to which other halogenated gases are often compared| we examined the sensitivity of CFC-11 forcing to a number of assumptions. We find that the uncertainties in the calculated value of the radiative forcing caused by neglect of the temperature and pressure dependence of the IR absorption spectrum are much smaller than those resulting from uncertainties in the absolute absorption cross sections or the vertical profile of CFC-11. Our best estimate is 0.285 W m(-2) ppbv(-1)| which is 30% higher than the value adopted by the Intergovernmental Panel on Climate Change and is believed to be accurate to within about 10%. For the other gases represented here the lack of detailed knowledge of the likely vertical and horizontal distribution probably represents the most significant uncertainty in evaluating their radiative forcing. 4718,1997,5,4,Radiocarbon dating of a recent high-latitude peat profile: Stor Amyran| northern Sweden,The value of both high-precision (HP) and AMS C-14 determinations in the fine-resolution dating of recent peat at Stor Amyran| near Umea| northern Sweden has been explored. A detailed chronology of accumulation| based an C-14| an occurrence of the Askja AD 1875 tephra and Am-241 measurements has been derived for the last 700 years. This shows significant changes in the mass balance of the peat profile| with minimum rates of net carbon sequestration overlapping with the period of minimum spring and summer temperature documented by published tree-ring evidence. The paper presents a methodology for calculating empirically past changes in the rate of net carbon sequestration in boreal peatlands and for exploring the effects of climatic variations (and possible future global warming) on these rates. 2429,1997,5,4,Rapid climate change in the North Atlantic during the Younger Dryas recorded by deep-sea corals,Research on global climate change has increasingly focused on rapid (century-scale and decadal) changes. One such climate shift| the Younger Dryas cooling event(1)| took place during the last deglaciation| from 13|000 to 11|700 years BP. Climate records from Greenland ice cores and North Atlantic sediment cores show high-frequency fluctuations implying significant (>5 degrees C) shifts in temperature at this time| taking place within 50-100 years (ref. 2)| The origin of the Younger Dryas has recently been attributed to a reduction or cessation of deep-water production in the North Atlantic and a concurrent lessening of the heat flux from Low latitudes(3|4)| The role of intermediate waters (1|000-2|000 m depth) is less certain| however| because climate proxies for this ocean reservoir are rare and ambiguous. Here we report on the use of a new climate archive| deep-sea corals from Orphan knoll (1|600 m depth) in the northwestern Atlantic Ocean. The oxygen isotope ratios in the coral skeletons (accurately dated by the Th-230/U-234 chronometric method) change markedly coincident with the initiation of the Younger Dryas| suggesting that there were profound changes in intermediate-water circulation at this time. 4807,1997,4,4,Recent abnormal changes in wintertime atmospheric response to tropical SST forcing,An ensemble of climate experiments has been performed using a T42 GCM version of the Japan Meteorological Agency global model to examine abnormal changes in the wintertime extratropical atmospheric response to anomalous sea surface temperature (SST) forcing in recent decades. Three independent 39-year integrations for the period 1955-1993 are forced by the same observed SST boundary condition. Although the tropical Pacific SST anomalies since the late 1980s indicate El Nine-like patterns| the Pacific/North American teleconnection (PNA) pattern is found to be hardly simulated| which stands in sharp contrast with that for the period 1977-1983. The SSTs in the vicinity of the maritime continent (the Indonesian region)| including the tropical Indian. Ocean| are very high during the period 1987-1993 and associated model atmosphere does undergo pronounced zonal heating over almost the entire tropics. Such tropical heating does not necessarily favor the barotropic Rossby wave dispersion into the extratropics emanating out of convective forcing since weakened Walker circulation is not capable of producing localized strong divergence anomalies| hence inhibiting generation of apparent vorticity sources in the subtropics. If the prevailing tendency of high SSTs in the vicinity of the maritime continent persists from now on| it is anticipated that a good correlation between EI Nino-Southern Oscillation (ENSO) and PNA| which has been pointed out by previous numerous studies| becomes insignificant. This anomalous feature may be viewed as a signature of global warming. 2393,1997,2,4,Recent advances in studies of anthracnose of Stylosanthes. V. Advances in research on Stylosanthes anthracnose epidemiology in Australia,Epidemiological research on anthracnose disease of style in Australia has improved understanding of the disease cycle through quantifying interaction between host| pathogen and the environment. Research has focused on: pathogenic and genetic variation in the Australian population of Colletotrichum gloeosporioides in comparison with diversity at the centre of origin for this pathogen in South America; environmental influences on anthracnose development and survival as a means to understand better the effectiveness of host resistance; and epidemiological consequences of strategies for the deployment of host-resistance genes. Through a close collaboration with breeding and cultivar development work| this research has helped to characterise and utilise better resistance for the management of anthracnose. Recently| a novel approach| using multivariate analysis| has been used to classify isolates into races taking into account the variation between pathogenicity assays. Both pathogenic and selection-neutral molecular markers have been used to reveal a limited range of variation in the Australian pathogen population compared with that at the centre of origin. This finding has important quarantine implications. The influence of weather factors in the dispersal| infection and survival of C. gloeosporioides has been established to characterise better the forms of genetic resistance which are prone to environmental variation. Evolutionary consequences of style genotype mixtures have been established to show that changes in race frequency can occur rapidly in the pathogen population| perhaps following changes in the composition of the host population due to outcrossing. As a model system| style anthracnose disease is being used to study the impact of predicted global climate change on plant diseases and the application of a 3-dimensional visual simulation model| 'virtual plant'| to understand better the dynamics of disease and pest development within a plant canopy. An important feature of this research has been the effective national and international collaboration. With new opportunities for international research| this collaboration is expected to grow in strength and stature to help manage this important disease. 4776,1997,3,4,Recent advances in the catalytic properties of metastable materials,New catalysts and electrocatalysts which are amorphous alloys themselves or prepared from amorphous and other metastable alloys are reviewed in this paper. The most important characteristic of metastable materials including amorphous and nanocrystalline alloys from the chemical point of view is the homogeneous single phase nature consisting of a variety of elements| whose concentrations sometimes exceed the solubility limits at equilibrium. For the enhancement of the activity various treatments are carried out before catalytic reaction| such as oxidation-reduction and selective dissolution of alloy constituents. For example| after immersion in HF| amorphous Cu-Zr alloys show higher activity than amorphous Cu-Ti alloys for dehydrogenation of 2-propanol and hydration of acrylonitrile. This is due to dissolution of smaller amounts of titanium from Cu-Ti alloys than dissolution of zirconium from Cu-Zr alloys in HF| since the corrosion resistance of titanium in HF is higher than zirconium. The catalysts prepared from some amorphous nickel alloys are most effective for methanation of CO2 at atmospheric pressure. Amorphous nickel-refractory metal alloys are the best cathode materials for electrolytic hydrogen evolution. The catalyst for CO2 methanation and the electrode for electrolytic hydrogen evolution are used for building a CO2 recycling plant to avoid global warming and to supply abundant energy. (C) 1997 Elsevier Science S.A. 2418,1997,2,4,Reconstruction and analysis of historical changes in carbon storage in arctic tundra,Surface air temperature in arctic regions has increased since pre-industrial times| raising concerns that warmer and possibly drier conditions have increased soil decomposition rates| thereby stimulating the release to the atmosphere of the large stores of carbon (C) in arctic soils. We used a model (MEL-GEM| Marine Biological Laboratory General Ecosystem Model) of ecosystem C and nitrogen (N) dynamics to predict and analyze historical (1829-1990) changes in C storage in a N-limited| tussock-tundra ecosystem near Toolik Lake on the North Slope of Alaska. The model simulates stand-level photosynthesis and N uptake by plants| allocation of C and N to foliage| stems| and fine roots| respiration in these tissues| turnover of biomass through litterfall| and decomposition of litter and soil organic matter. We first calibrated the model by deriving a single parameter set that closely simulated the response of tussock tundra to decade-long experimental manipulations of nutrients| temperature| light| and atmospheric CO2. The calibrated model predicts that historical increases in temperature and atmospheric CO2 have increased total ecosystem C storage. Higher temperatures increased soil and plant respiration| but those losses of C were overcompensated by increased photosynthesis resulting from redistribution of N from soil to plants. This redistribution of N was due to increased net mineralization and uptake of N. Increases in atmospheric CO| also increased photosynthesis| but consequent increases in C storage were constrained by limits on increases in the C:N ratio of vegetation. In contrast| hypothesized historical decreases in soil moisture substantially decreased simulated total ecosystem C storage as a result of large increases in soil respiration. With decreased soil moisture| increases in photosynthesis associated with redistribution of N from soil to plants only partially compensated for respiratory C losses| as plant uptake of N could not keep pace with increased N mineralization rates. Consequent losses of N from the ecosystem contributed to the declines in C storage under drier conditions. Based on the combined effects of reconstructed historical changes in atmospheric CO2| mean growing-season temperature| and two alternative soil moisture scenarios| the model predicts a -5.4 to +2.3% change in ecosystem C from 1829 to 1990. These estimates are consistent with field evidence that historically recent changes in C storage of tussock tundra have been relatively small. However| the model also predicts that relatively large transient losses of ecosystem C (50-180 g.m(-2).yr(-1)) may frequently have occurred since the late 1800s| with one of the largest simulated C losses of the 20th century occurring from 1988 to 1990 (3-yr average = 133 g C.m(-2).yr(-1)). These simulated losses were similar to losses measured in tussock tundra at Toolik Lake from 1983 to 1990 (e.g.| 1990 losses = 156 g Cm-2.yr(-1)) but nonetheless suggest that these measured losses may be transitory in nature. 2414,1997,2,4,Regional and temporal variation in net primary production and nitrogen mineralization in grasslands,Spatial variability that occurs at large scales has long been used by ecologists as a tool to examine the controls over ecosystem structure and function. Correlations of control variables such as climatic factors and response variables such as vegetation and soil carbon storage across broad regions have played a crucial role in predicting the response of ecosystems to global climate change. Despite the importance of these large-scale space-for-time substitutions| there are substantial limitations. One of these limitations is that many of the possible control factors covary with one another| and only some of the important control factors actually exist in large-scale databases. Thus| the true proximal controls may be difficult to identify. A second limitation is that models of spatial variability may not be appropriately applied to temporal variability. In this paper| we utilize a new approach to determine the extent to which N availability may constrain aboveground primary productivity in the Central Grassland region of the U.S. The strong relationship between average annual primary production and average annual precipitation found in spatial patterns in ecosystems globally has often been interpreted as evidence of a fundamental water limitation. However| temporal variation in annual aboveground net primary production (ANPP) indicates that other factors constrain production. We generated a spatial and temporal database for annual aboveground net primary production and annual net N mineralization by linking a database of input variables (precipitation| temperature| and soils) with predictive models. We generated independent data sets of aboveground net primary production and net N mineralization by using regression models to predict aboveground net primary production| and the Century model to simulate net N mineralization. Our analyses indicate that net primary production and net N mineralization both increase with mean annual precipitation; thus| it is not possible to separate the extent to which ANPP is controlled by water or N availability. Nitrogen use efficiency (NUE) increased with increasing precipitation across the region. Aboveground net primary production decreased with increasing temperature across the region| while N mineralization increased slightly| leading to decreasing (NUE) with increasing temperature. At high precipitation levels| aboveground net primary production increased and N mineralization decreased slightly with increasing soil fineness. Nitrogen use efficiency generally increased with increasing pools of soil organic matter| likely because in grasslands| the proportion of recalcitrant organic matter increases with the total organic matter pools. A comparison of interannual variation in net N mineralization with average spatial variation indicated a high degree of inertia in the response of N availability to precipitation levels. Our simulation results as well as field results of Lauenroth and Sala (1992) raise important questions about the applicability of space-for-time substitutions when dealing with ecosystem function. The structure of the systems appears to provide important constraints on the temporal variability that are not evident in an analysis of spatial variability. 4794,1997,2,2,Regional climate change scenarios under global warming in Kazakhstan,The aim of this paper is to report on the development of regional climate change scenarios for Kazakhstan as the result of increasing of CO2 concentration in the global atmosphere. These scenarios are used in the assessment of climate change impacts on the agricultural| forest and water resources of Kazakhstan. Climate change scenarios for Kazakhstan to assess both long-term (2 x CO2 in 2075) and short-term (2000| 2010 and 2030) impacts were prepared. The climate conditions under increasing CO2 concentration were estimated from three General Circulation Models (GCM) outputs: the model of the Canadian Climate Center Model (CCCM)| the model of the Geophysical Fluid Dynamics Laboratory (GFDL) and the 1% transient version of the GFDL model (GFDL-T). The near-term climate scenarios were obtained using the probabilistic forecast model (PFM) to the year 2010 and the results of GFDL-T for years 2000 and 2030. A baseline scenario representing the current climate conditions based on observations from 1951 to 1980 was developed. The assessment of climate change in Kazakhstan based on the analysis of 100-years observations is given too. As a result of comparisons of the current climate (based on observed climate) the 1 x CO2 output from GCMs showed that the GFDL model best matches the observed climate. The GFDL model suggests that the minimum increase in temperature is expected in winter| when most of the territory is expected to have temperatures 2.3-4.5 degrees C higher. The maximum (4.3 to 8.2 degrees C) is expected to be in spring. CCCM scenario estimates an extreme warming above 11 degrees C in spring months. GFDL-T outputs provide an 'intermediate' scenario. 2437,1997,4,4,Research and measurement program at the ANTARES AMS facility,The ANTARES AMS facility is fully operational and supports a research program in environmental science| with emphasis on global climate change and nuclear safeguards. A measurement program for external projects involving Australian and overseas institutions is also carried out| mainly in Quaternary science studies. 2450,1997,2,4,Response of ovule development and post-pollen production processes in male-sterile tomatoes to chronic| sub-acute high temperature stress,In order to determine the effects of high temperature on ovule development and reproductive processes subsequent to pollen production| nine day/night temperature combinations were imposed over a 9 month period as four separate experiments| each with three treatments| including one common treatment. In order to eliminate known effects of high temperatures on pollen production and stylar position| high temperature treatments were applied only to male-sterile tomatoes (Lycopersicon esculentum Mill.). Pollen was obtained from male-fertile plants given optimal growth conditions. This allowed comparison of mean daily temperatures from 25-29 degrees C; day/night temperature differentials (DIFs) of 2| 6| and 10 degrees C; day temperatures of 28| 30 and 32 degrees C at night temperatures of 22| 24| and 26 degrees C; and night temperatures of 22| 24 and 26 degrees C at day temperatures of 28| 30 and 32 degrees C. Average weight per fruit and flower number did not demonstrate a consistent pattern of response to high temperature. Other reproductive characteristics (% fruitset| total number and weight of fruit per plant| and seediness index) decreased as mean daily temperature rose from 25 degrees C to 26 degrees C and from 28 degrees C to 29 degrees C. The primary parameter affecting these variables was mean daily temperature| with day temperature having a secondary role. thus| in determining reproductive responses of tomato to temperatures within this range| day temperature| night temperature and DIFs do not need to be considered independently of their effect on mean daily temperature. If this relationship holds true in other species| and for pre-pollen production processes as well| modelling the effects of projected climate change should be simplified. 4756,1997,3,3,Review of controls of NOx,The oxidation state and high temperature flames within a glass furnace promote the evolution of high concentrations of the oxides of nitrogen (NOx). These are toxic gases that adversely affect the eyes and lungs| contribute to acid rain and global warming and are precursors to ground level ozone formation and photochemical fog. European Council Directive 96/61/EC of September 1996 (IPPC) requires the glass industry (amongst others) to define Best Available Techniques for controlling the main polluting substances. The present paper categorises the various NOx reduction techniques in terms of effectiveness| costs and environmental impact. 4786,1997,4,4,Role of spatial and temporal variations in the computation of radiative forcing and GWP,We investigate the role of spatial and temporal resolution for estimation of radiative forcing due to SF6 and a range of halocarbons as well as CO2. A broadband model| which is used in the calculations| is described. Some comparative calculations have also been performed with a|line-by-line model. The most detailed horizontal resolution used is 2.5 degrees x 2.5 degrees in latitude and longitude. A variety of resolutions up to global averages are investigated. The effects of variations on diurnal| monthly| and seasonal scales are also studied. Spatial and temporal variation in the radiative forcing due to variations in temperature| humidity| and cloudiness has been taken into account on the basis of observed data. Inaccuracies due to temporal variations are small in all cases (up to about 1%). Deviations in forcings due to spatial averaging are also small (less than 1%) as long as latitudinal variations are resolved| but significant inaccuracies are introduced when global averaged conditions are assumed. The forcing due to CO2 responds somewhat differently to spatial averaging compared to SF6 and the halocarbons| so global warming potential (GWP) values for SF6 and halocarbons with CO2 as a reference gas are less accurate. Resolution of latitudinal variations in input parameters is shown to increase the accuracy of the GWP values for SF6 and the halocarbons. The choice of tropopause level| where radiative forcing is determined| is shown to be crucial| with differences up to 10% in the global average radiative forcing for different assumptions. 2426,1997,2,4,Sea-level rise impact on coastal areas of Estonia,Due to long coastline (3|794 km in total) and extensive low-lying coastal areas| global climate change through sea-level rise will strongly affect the territory of Estonia. A number of valuable natural ecosystems (both| marine and terrestrial) containing rare plant communities often rich in species| but also suitable breeding places for birds will be in danger. Most sandy beaches high in recreative value will disappear. However| isostatic land uplift and location of coastal settlements at a distance from the present coastline reduce the rate of risk. Four case study areas characterizing all the shore types of Estonia have been selected for sea-level rise vulnerability and adaptation assessment. Preliminary results and estimates of vulnerability to 1.0 m sea-level rise by 2075 for two case study areas - Hiiumaa| West-Estonian Archipelago and Parnu-Ikla| south-western coast of the mainland are presented in this paper. 4760,1997,4,4,Self-stabilization of the biosphere under global change: a tutorial geophysiological approach,A 2-dimensional extension of the simple Lovelock-Watson model for geosphere-biosphere feedback is introduced and discussed. Our enriched version also takes into account various pertinent physical| biological| and civilisatory processes like lateral heat transport| species competition| mutation| germination| and habitat fragmentation. The model is used as a caricature of the Earth System| which allows potential response mechanisms of the biosphere to environmental stress (as generated| e.g.| by global warming or anthropogenic land-cover change) to be investigated qualitatively. Based on a cellular automaton representation of the system| extensive calculations are performed. They reveal a number of remarkable and| partially| counter-intuitive phenomena: our model biosphere is able to control almost perfectly the geophysical conditions for its own existence. If the environmental stress exceeds certain thresholds| however| life breaks down on the artificial planet via a first-order phase transition| i.e.| in a non-reversible way. There is a close connection between self-stabilizing capacity| biodiversity and geometry of habitat fragmentation. It turns out| in particular| that unrestricted Darwinian competition| which reduces the number of co-existing species| is the best guarantee for survival of the artificial ecosphere as a whole. 2432,1997,2,4,Sensitivity of flood events to global climate change,The sensitivity of Acheloos river hood events at the outfall of the mountainous Mesochora catchment in Central Greece was analysed under various scenarios of global climate change. The climate change pattern was simulated through a set of hypothetical and monthly GISS (Goddard Institute for Space Studies) scenarios of temperature increase coupled with precipitation changes. The daily outflow of the catchment| which is dominated by spring snowmelt runoff| was simulated by the coupling of snowmelt and soil moisture accounting models of the US National Weather Service River Forecast System| Two threshold levels were used to define a flood day-the double and triple long-term mean daily streamflow-and the flood parameters (occurrences| duration| magnitude| etc.) for these cases were determined. Despite the complicated response of flood events to temperature increase and threshold| both hypothetical and monthly GISS representations of climate change resulted in more and longer flood events for climates with increased precipitation. All climates yielded larger flood volumes and greater mean values of flood peaks with respect to precipitation increase. The lower threshold resulted in more and longer flood occurrences| as well as smaller flood volumes and peaks than those of the upper one. The combination of higher and frequent flood events could lead to greater risks of inundation and possible damage to structures. Furthermore| the winter swelling of the streamflow could increase erasion of the river bed and banks and hence modify the river profile. 4828,1997,2,3,Sensitivity of malaria| schistosomiasis and dengue to global warming,Global assessment of the potential impacts of anthropogenically-induced climate change on vector-borne diseases suggests an increase in extent of the geographical areas susceptible to transmission of malarial Plasmodium parasites| dengue Flavivirus and Schistosoma worms. The transmission potential of the three associated vector-borne diseases studied is highly sensitive to climate changes on the periphery of the currently endemic areas and at higher altitudes within such areas. Our findings vis-a-vis the present endemic areas indicate that the increase in the epidemic potential of malaria and dengue transmission may be estimated at 12-27% and 31-47%| respectively| while in contrast| schistosomiasis transmission potential may be expected to exhibit a 11-17% decrease. 4793,1997,2,4,Sensitivity of the Russian agriculture to changes in climate| CO2 and tropospheric ozone concentrations and soil fertility,Russian agriculture sensitivity to changes in climate| soil and atmosphere chemistry were analyzed. Calculated data are presented on crop productivity of grain crops and grasses (C-3) under arid and humid scenarios of climate taking account of one-| two-| three and four-factor natural environment impacts. All four factors under studies (climatic parameters| CO2 and tropospheric ozone concentrations| soil degradation extent) greatly impact agriculture productivity. The effect of interaction between all considered factors on agroecosystem productivity is studied. it is established that a simple additive scheme for explaining the complex effect of some factors can be much violated. In this case| not only variations in the mean crop yield levels but also variations in the degree of crop stability have been assessed in some regions| that may be more important for determining the social-economic consequences. It turned out that the recurrence of critically very low yields in steppe regions may increase two fold as a result of global warming. 4709,1997,3,3,Sensitivity study of optimal CO2 emission paths using a simplified structural integrated assessment model (SIAM),A structurally highly simplified globally integrated coupled climate-economic costs model SIAM (Structural Integrated Assessment Model) is used to compute optimal paths of global CO2 emissions that minimize the net sum of climate damage and mitigation costs. The model is used to study the sensitivity of the computed optimal emission paths with respect to various critical input assumptions. The climate module is represented by a linearized impulse-response model calibrated against a coupled ocean-atmosphere general circulation climate model and a three-dimensional global carbon-cycle model. The cost terms are represented by strongly simplified expressions designed for maximal transparency with respect to sensitive input assumptions. These include the discount rates for mitigation and damage costs| the inertia of the socio-economic system| and the dependence of climate damages on the change in temperature and the rate of change of temperature. Different assumptions regarding these parameters are believed to be the cause of the marked divergences of existing cost-benefit analyses based on more sophisticated economic models. The long memory of the climate system implies that very long time horizons of several hundred years need to be considered to optimize CO2 emissions on time scales relevant for a policy of sustainable development. Cost-benefit analyses over shorter time scales of a century or two can lead to dangerous underestimates of the long term climatic impact of increasing greenhouse-gas emissions. To avert a major long term global warming| CO2 emissions need to be reduced ultimately to very low levels. However| the draw-down can be realized as a gradual transition process over many decades and even centuries. This should nevertheless not be interpreted as providing a time cushion for inaction: the transition becomes more costly the longer the necessary mitigation policies are delayed. However| the long time horizon provides adequate flexibility for later adjustments. Short term energy conservation alone is insufficient and can be viewed only as a useful measure in support of the necessary long term transition to carbon-free energy technologies. For standard climate damage cost expressions| optimal emission paths limiting long term global warming to acceptable sustainable development levels are recovered only if climate damage costs are not significantly discounted. Discounting of climate damages at normal economic rates yields emission paths that are only weakly reduced relative to business as usual scenarios| resulting in high global warming levels that are incompatible with the generally accepted requirements of sustainable development. The solutions are nevertheless logically consistent with the underlying discounting assumption| namely that the occurrence of global warming damages in the distant future as a result of present human activities is of negligible concern today. It follows that a commitment to long term sustainable development| if it in fact exists| should be expressed by an intertemporal relation for the value of the earth's future climate which does not degrade significantly over the time horizon relevant for climate change. Since the future climate is a common assett whose value cannot be determined on the market| the appropriate discount rate for future climate damages should be determined by an assessment of the public willingness to pay today for the mitigation of future climate change. To translate our general conclusions into quantitative cost estimates required by decision makers| the present exploratory study needs to be extended using more detailed disaggregated climate damage and mitigation cast estimates and more realistic socioeconomic models| including multi-actor interactions| inherent variability| the role of uncertainty and adaptive control strategies. 4689,1997,2,3,Simulated changes in the Asian summer monsoon at times of increased atmospheric CO2,Possible changes in the Asian summer monsoon due to increased atmospheric CO2 are investigated by an MRI global coupled atmosphere-ocean general circulation model. The summer (June-August) monsoon rainfall in India increases significantly with global warming. On the other hand| the monsoon wind shear index| defined as the difference between 850 hPa and 200 hPa zonal winds over the northern Indian Ocean| decreases. At 850 hPa| the westerly wind shifts northward and intensifies from the Sahel to northwest of India| but the monsoon westerly over the Arabian Sea weakens. It is found that increased moisture content in the warmer air leads to larger moisture flux convergence| contributing to the increased rainfall. Therefore| the monsoon wind shear index is not a good indicator for identifying any change of monsoon accompanying global warming. In contrast to the increased rainfall in India| change in rainfall is little over China where soil moisture becomes drier at times of increased CO2. It is also noted that the northern Eurasian continent becomes wetter in the increased-CO2 climate. The magnitude of the interannual variability of the Asian summer monsoon rainfall becomes larger in the CO2 experiment than in the control experiment| particularly in the later stage of the experiment after CO2 doubling. However it should be noted that the interdecadal variation of this interannual variability is also large both in the control and the CO2 experiments. 2390,1997,2,4,Simulated sea level change alters anatomy| physiology| growth| and reproduction of red mangrove (Rhizophora mangle L.),Tropical coastal forests - mangroves - will be one of the first ecosystems to be affected by altered sea levels accompanying global climate change. Responses of mangrove forests to changing sea levels depend on reactions of individual plants| yet such responses have not been addressed experimentally. We report data from a long-term greenhouse study that assessed physiological and individual growth responses of the dominant neotropical mangrove| Rhizophora mangle| to levels of inundation expected to occur in the Caribbean within 50-100 years. In this study| we grew potted plants in tanks with simulated semidiurnal (twice daily) high tides that approximated current conditions (MW plants)| a 16-cm increase in sea level (LW plants)| and a 16-cm decrease in sea level (HW plants). The experiment lasted 2% years| beginning with mangrove seedlings and terminating after plants began to reproduce. Environmental (air temperature| relative humidity| photosynthetically active radiation) and edaphic conditions (pH| redox| soil sulfide) approximated field conditions in Belize| the source locale for the seedlings. HW plants were shorter and narrower| and produced fewer branches and leaves| responses correlated with the development of acid-sulfide soils in their pots. LW plants initially grew more rapidly than MW plants. However| the growth of LW plants slowed dramatically once they reached the sapling stage| and by the end of the experiment| MW plants were 10-20% larger in all measured growth parameters. Plants did not exhibit differences in allometric growth as a function of inundation. Anatomical characteristics of leaves did not differ among treatments. Both foliar C:N and root porosity decreased from LW through MW to HW. Relative to LW and HW plants| MW plants had 1-7% fewer stomata/mm(2)| 6-21% greater maximum photosynthetic rates| 3-23% greater absolute relative growth rates (RGRs)| and a 30% higher RCR for a given increase in net assimilation rate. Reduced growth of R. mangle under realistic conditions approximating future inundation depths likely will temper projected increased growth of this species under concomitant increases in the atmospheric concentration of CO2. 4888,1997,3,2,Simultaneous production of electricity| steam| and CO2 from small gas-fired cogeneration plants for enhanced oil recovery,In recent years| global warming has been blamed on the so called ''greenhouse effect'' and has caught the attention of scientists and politicians throughout the world. There is an increasing concern surrounding the emission levels of greenhouse gases| particularly carbon dioxide (CO2). This paper is an extension of earlier work((1)) to show how cogeneration concepts can be used to reduce production costs by simultaneously producing electricity| CO2 and steam for enhanced oil recovery (EOR) applications. (C) 1997 Elsevier Science Ltd. 4686,1997,2,4,Soil carbon cycling at a black spruce (Picea mariana) forest stand in Saskatchewan| Canada,Stored amounts and flow rates of soil carbon were measured simultaneously with soil environmental conditions (temperature and moisture content) periodically during the growing seasons from 1994 to 1995 at two plots (plot A was a dry soil condition| and plot B was a wet condition) in a black spruce (Picea mariana) forest stand in the Prince Albert area of Saskatchewan| Canada. Seasonal trends in litterfall rate and accumulation of the A(0) layer were not observed| while the total and mineral soil respiration rates changed seasonally with soil temperature. There was no significant relationship between soil moisture content and-any how rates or accumulations of soil carbon. Soil respiration and loss of litter might have been very low during the winter (November to early May) because of the frozen soil. The annual soil carbon cycling was analyzed by a compartment model| based on the data obtained in this study. The relative decomposition rate of the A(0) layer and humus in the mineral soil were estimated at 0.0632 yr(-1) and 0.0045 for plot A and 0.0284 yr(-1) and 0.0020 for plot B| respectively. These values indicate that the soil carbon cycling in plot A was about twice as fast as that in plot B. The slower cycling in plot B may be caused by the lower soil temperature and humid soil conditions| since the groundwater level is higher in plot B. The soil in both plots were accumulating carbon| i.e.| 0.13 t C ha(-1) yr(-1) for plot A and 0.03 for plot B. The soil carbon cycling in the boreal forest stand was slower because of the lower soil temperature than that reported in the cool- and warm-temperate forests. Soil carbon cycling in the boreal forest predominantly occurred at the surface of the mineral soil| suggesting that the decomposition response of soil organic matter in the boreal forest will be enhanced compared to other climate zone forests because of the large predicted temperature increase in the boreal zone under global warming. 4803,1997,3,3,Soil management and nitrous oxide emissions from cultivated fields in southern Ohio,Nitrous oxide (N2O) is an important atmospheric trace gas due to its involvement in the postulated global warming phenomenon and in the depletion of the ozone layer. Widespread concern has been triggered by recent reports of increased atmospheric N2O concentration. Since agriculture has been implicated as one contributor to that increase| a monitoring program was undertaken during the 1993 and 1994 cropping season (May-October) to evaluate the effect of several soil management practices on N2O emission from soil. Our results show that rates of N2O emission were generally near baseline levels during most sampling occasions| Major| but short-lived| fluxes of N2O were observed after rainfall events and during the days immediately following fertilizer application. It was during these times that most of the seasonal N2O loss occurred. An excellent relationship was found between seasonal N2O loss (y) and the maximum daily flux of N2O (x) during a season (v = -0.4x(2) + 43.1 x + 338| r(2) = 0.89| P < 0.0001). The N2O emission data were log normally distributed for both years| Average daily emissions of N2O were 6.9 +/- 6.3 g (range| 0.3-74.7 g) N2O-N ha(-1) day(-1) and 17.6 +/- 10.5 g (range| 0.1-326 g) N2O-N ha(-1) day(-1) during the 1993 and 1994 seasons| respectively. Seasonal N2O-N losses were| in general| highest in the continuous corn (CC) (Zea mays L.) plots and lowest in the soybean (Glycine max L.) plots of the corn/soybean/wheat (Triticum aestivum L.)-hairy vetch (Vicia villosa Roth) rotation (CSW-V). Average N loss as N2O during a cropping season was between 0.6 kg (for the soybean crop of the CSWV rotation and ridge till treatment) and 3.7 kg N2O-N ha(-1) year(-1)| (for the CC rotation and the chisel till treatment). Approximately 0.5-3% of the inorganic N fertilizer added was lost as N2O. Our data show that seasonal N2O-N loss from chisel-till plots were generally significantly higher than From no-till or ridge till plots. 2382,1997,2,4,Soil-atmosphere fluxes of carbon monoxide during early stages of postfire succession in upland Canadian boreal forests,Soil-atmosphere fluxes of carbon monoxide (GO) were investigated during BOREAS 1994 (June to September 1994) in forest sites near the northern study area (NSA) of the Boreal Ecosystem-Atmosphere Study (BOREAS). Fluxes and related ancillary data were measured for both upland black spruce (located on poorly drained clay-textured soils) and jack pine sites (well-drained sandy soils) that were in early stages of succession following stand replacement fires that occurred within 7 years of BOREAS 1993. Nearby control stands that had not burned in the past 80 years were studied for comparison. Net fluxes measured by using transparent closed chambers were generally positive at the warmer| sunlit burn sites but negative (sink activity) in the shaded| cooler control sites. Carbon monoxide uptake in controls| which was first order with respect to CO concentration| was little affected by covering the sampling chambers to exclude light. Median deposition velocities calculated from the uptake fluxes were 0.015 cm s(-1) at the black spruce control site and 0.0055 cm s(-1) at the jack pine control site| at the lower end of the range of values observed by others in tropical and temperate ecosystems. Daytime CO fluxes at the burn sites were generally positive (10(11)-10(12) molecules cm(-2) s(-1)) and were lowered when solar irradiance was excluded from the chambers by covering or when cloudiness or smoke reduced the light intensity. Net fluxes at the burn sites were controlled by competition between abiotic production| mainly at the surface| and by oxidation deeper in the soil. Abiotic production| which was attributable to photoproduction and thermal decomposition of the surface organic layer and charcoal| strongly correlated with incident solar irradiance| and thus the greatest fluxes were observed during midday. Results of these studies indicate that the locally dependent changes in boreal fire return intervals that are linked to global climate change represent an important biospheric/physical feedback that is likely to alter the biosphere-atmosphere exchange of CO. 4882,1997,3,4,Solar cell materials| technologies| applications and their impact on developing countries,Ecological concern is growing as the world approaches the twenty-first century. The widening gap between electricity demand and generation| especially in developing and newly industrialised countries| is increasing the pressure for increased power generation. This will result in staggering amounts of air pollution if the world continues to depend on oil and fossil fuels. The development of clean energy sources has thus become an important task in arresting gas emissions and in protecting the Earth's eco-system. This article reviews the place of solar photovoltaic technology in the quest for clean energy. 2397,1997,4,3,Solar forcing of global climate change since the mid-17th century,Spacecraft measurements of the sun's total irradiance since 1980 have revealed a long-term variation that is roughly in phase with the 11-year solar cycle. Its origin is uncertain| but may be related to the overall level of solar magnetic activity as well as to the concurrent activity on the visible disk. A low-pass Gaussian filtered time series of the annual sunspot number has been developed as a suitable proxy for solar magnetic activity that contains a long-term component related to the average level of activity as well as a short-term component related to the current phase of the I I-year cycle. This time series is also assumed to be a proxy for solar total irradiance| and the irradiance is reconstructed for the period since 1617 based on the estimate from climatic evidence that global temperatures during the Maunder Minimum of solar activity| which coincided with one of the coldest periods of the Little Ice Age| were about 1 degrees C colder than modem temperatures. This irradiance variation is used as the variable radiative forcing function in a one-dimensional ocean-climate model| leading to a reconstruction of global temperatures over the same period| and to a suggestion that solar forcing and anthropogenic greenhouse-gas forcing made roughly equal contributions to the rise in global temperature that took place between 1900 and 1955. The importance of solar variability as a factor in climate change over the last few decades may have been underestimated in recent studies. 2428,1997,2,4,Spruce and fir regeneration and climate in the forest-tundra ecotone of Rocky Mountain National Park| Colorado USA,As an ecological boundary zone| the forest-tundra ecotone is a valuable location to study the initial response of vegetation to global climate change. The purpose of this study is to predict the potential response of the forest-tundra ecotone in Rocky Mountain National Park to future climate change using data on historical episodes of establishment in patch forest openings of the forest-tundra ecotone. We hypothesized that recent seedling establishment in patch forest openings of the forest-tundra ecotone| not balanced by mortality| was triggered by a warm| but wet period following the end of the Little Ice Age ca. A.D. 1850. At four sampling locations distributed throughout the Park| we determined dates of establishment among patch forest trees using increment cores and basal disks. We studied the relationship between establishment dates in relation to historical climate records using t-tests and logistic regression. In Rocky Mountian National Park| tree invasion in patch forest openings is episodic in nature| concentrated between 1951-1964| and is not balanced by mortality| suggesting more than a short-term change in the ecotone. On the basis of the climate record| t-tests| and logistic models| we concluded that both high temperatures and high snow depths must occur simultaneously for several years in order to generate climatic conditions suitable for tree establishment. The historic climate record indicates that a warmer and wetter period occurred during the 1950s and 1960s| but climate data are unavailable before 1880. According to proxy climate records| it appears that the regional climate of the southern Rocky Mountain region has been both warmer and wetter since the end of the Little Ice Age (ca. A.D. 1350-1850). We conclude that these climatic conditions may be related to the tree invasion we observed in patch forest openings of Rocky Mountain National Park. 4812,1997,4,4,Spurious trends in satellite MSU temperatures from merging different satellite records,Analysis of global surface air temperature records has indicated that recent years have been among the warmest since the late nineteenth century(1)| with 1995 being the warmest year on record(2)| But the rate of global annual mean surface warming of 0.13 degrees C per decade during the period 1979-95 differs substantially from the global lower-tropospheric cooling trend of -0.05 degrees C per decade(3) inferred from the record (MSU-2R) of radiance measurements by the satellite Microwave Sounder Unit (MSU)(4|5). Accordingly| the satellite record has been widely cited by sceptics as evidence against global warming(6-10). However| a substantial fraction of the measured radiance originates not from the atmosphere but from the Earth's surface(11)| and gives rise to high noise levels| This noise can lead to errors when merging temperature time series obtained from different satellites. Here we present comparisons among different MSU retrievals| sea surface temperatures (SSTs)| and equivalent MSU temperatures derived from an atmospheric general circulation model forced with observed SSTs. The comparisons| focused on the tropics where atmospheric temperatures are closely tied to SSTs| strongly suggest that two spurious downward jumps occur in the MSU-2R record coinciding with changes in satellites| and that the real trend in MSU temperatures is likely to be positive| albeit small. 4766,1997,3,2,Stabilization of the greenhouse impact caused by anthropogenic emissions from Nordic countries,The possibility of decreasing the Nordic countries' contribution to global warming in the future is examined. Anthropogenic carbon dioxide (CO2)| methane (CH4)| and nitrous oxide (N2O) emissions are considered. Global average radiative forcing is used as a measure of the greenhouse impact caused by the emissions. Past emissions are included in the study because they have impact far into the future. The calculation method utilized in this study can be applied to any other country. Two hypothetical future emission development cases are presented| and the radiative forcing caused by them is calculated. In the higher emission (case A) CO2 emissions remain above current level| while N2O and CH4 emissions decrease. In the lower emission (case B) the emissions decrease to about one-tenth of the current emissions by the year 2100. Only if very strict emission reductions (case B) take place will the greenhouse impact of the Nordic countries return to current levels during next century. Likewise| the per capita radiative forcing of Nordic countries will remain above global average unless the emissions decrease drastically (case B) and the current population levels are used in per capita calculation. 4894,1997,3,4,Status report on the development of a liquid HFC blowing agent,CFC blowing agents have been eliminated from virtually all polyurethane foam applications and replaced| in many cases| with the more environmentally acceptable HCFCs. In many applications the preference has been to convert from one liquid blowing agent to another| i.e.| from CFC-11 to HCFC-141b. With the planned phaseout of HCFC-141b less than a decade away| there is a clear need for a ''next generation'' liquid blowing agent to eventually replace HCFC-141b. Previously| we reported the results of preliminary performance evaluations of four promising liquid HFC blowing ag-ent candidates and the screening process used to select those four candidates. In this paper we discuss the environmental| toxicological and performance characteristics of our primary liquid HFC blowing agent candidate. The first criterion for a new blowing agent is environmental acceptability. A candidate must have a zero Ozone Depletion Potential (ODP) and a low Global Warming Potential (GWP)| and should be free from other environmental concerns. Accordingly| the paper begins with a discussion of environmental properties such as atmospheric lifetime and GWP. It is equally important that the toxicological properties of a blowing agent candidate be well understood. The results of early toxicity tests have been very promising. These are reported along with a proposed timetable for additional toxicity testing. Ultimately| the acceptability of a new blowing agent will be based on performance. Data from laboratory foam evaluations involving both polyurethane and polyisocyanurate foams are presented. In addition to foam properties| other key performance characteristics such as plastics compatibility| blowing agent stability| foam premix stability and decomposition have been evaluated and are discussed. 2421,1997,2,3,Stem respiration of ponderosa pines grown in contrasting climates: Implications for global climate change,We examined the effects of climate and allocation patterns on stem respiration in ponderosa pine (Pinus ponderosa) growing on identical substrate in the cool| moist Sierra Nevada mountains and the warm| dry| Great Basin Desert. These environments are representative of current climatic conditions and those predicted to accompany a doubling of atmospheric CO2| respectively| throughout the range of many western north American conifers. A previous study found that trees growing in the desert allocate proportionally more biomass to sapwood and less to leaf area than montane trees. We tested the hypothesis that respiration rates of sapwood are lower in desert trees than in montane trees due to reduced stem maintenance respiration (physiological acclimation) or reduced construction cost of stem tissue (structural acclimation). Maintenance respiration per unit sapwood Volume at 15 degrees C did not differ between populations (desert: 6.39 +/- 1.14 SE mu mol m(-3) s(-1)| montane: 6.54 +/- 1.13 SE mu mol m(-3) s(-1)| P = 0.71) and declined with increasing stem diameter (P = 0.001). The temperature coefficient of respiration (Q(10)) varied seasonally within both environments (P = 0.05). Construction cost of stem sapwood was the same in both environments (desert: 1.46 +/- 0.009 SE g glucose g(-1) sapwood| montane: 1.48 +/- 0.009 SE glucose g(-1) sapwood| P = 0.14). Annual construction respiration calculated from construction cost| percent carbon and relative growth rate was greater in montane populations due to higher growth rates. These data provide no evidence of respiratory acclimation by desert trees. Estimated yearly stem maintenance respiration was greater in large desert trees than in large montane trees because of higher temperatures in the desert and because of increased allocation of biomass to sapwood. By analogy| these data suggest that under predicted increases in temperature and aridity| potential increases in aboveground carbon gain due to enhanced photosynthetic rates may be partially offset by increases in maintenance respiration in large trees growing in CO2-enriched atmospheres. 2438,1997,5,4,Stepwise climate change recorded in Eocene-Oligocene paleosol sequences from Central Oregon,Successions of paleosols bounded by erosional surfaces in fluvial sediments of the Eocene-Oligocene strata of Central Oregon can be interpreted as terrestrial equivalents of the unconformity-bound units of sequence stratigraphy. In the upper part of the upper Eocene Clarno Formation and in the lower part of the lower Eocene-lower Miocene John Day Formation| truncation surfaces separate otherwise conformable alluvial deposits and allow for stratigraphic subdivision into informal members (lower and upper ''Red Hill'' claystones in the Clarno Formation and lower| middle| and upper Big Basin Members and lower Turtle Cove Member in the John Day Formation). Paleosols in each member show a stepwise change in the degree of weathering of the most strongly developed paleosols: kaolinite-rich| Ultisol-like paleosols in lower ''Red Hill'' claystones (late Eocene| 42-43 Ma)| smectite-rich Alfisol-like paleosols in the upper ''Red Hill'' claystones (late Eocene| 41-42 Ma)| Alfisols and Ultisol-Like paleosols in the lower Big Basin Member (late Eocene| 34-40 Ma)| Alfisol and Inceptisol-like paleosols in the middle and upper Big Basin Members (early Oligocene| 30-34 Ma)| and calcic Inceptisol-like paleosols in the lower Turtle Cove Member (middle Oligocene| 28-30 Ma). These changes across the Eocene-Oligocene transition are interpreted as representing global cooling and drying of the midlatitudes from Eocene subtropical| humid conditions to Oligocene temperate| subhumid conditions. In central Oregon| these changes appear to be stepwise with climatically stable periods| represented by packages of similar paleosols| of approximately 2-4 m.y. in duration. Our interpretation of these paleosol packages as non-marine sequences is not based on correlation with sea-level changes but on correlation with global climate change events. Geomorphic processes influenced by climate and vegetation| and not base-level change| basin subsidence| or volcanic supply are thought to have controlled sedimentation rates. Thus| the stepwise increase in sedimentation rates across the Eocene-Oligocene transition in the central Oregon alluvial strata reflect increased sediment yields due to drying climatic conditions. High-precision Ar-40/Ar-39 age determinations of tuffs allow for the correlation of these sequences with the record of global climate change from deep sea cores. Three major paleoclimatic changes stand out. The change from Ultisol-Like paleosols formed in near-tropical climate to Alfisol-like paleosols formed in subtropical climate between 42.8 and 43 Ma corresponds to a global cooling trend after the mid-Eocene climatic optimum. The Eocene-Oligocene boundary (similar to 34 Ma) is marked by the change from subtropical Ultisol-like paleosols to Alfisol-like paleosols formed in temperate humid climate. Global cooling during the mid-Oligocene (similar to 30 Ma) is reflected in a change from non-calcareous| Alfisol-like paleosols to calcareous Andisol-like paleosols formed in sub-humid temperate conditions. These mid-Tertiary paleosol sequences are evidence of stepwise terrestrial climate change that was strongly coupled with marine events. 4724,1997,2,4,Stochastic hydrology in the context of climate change,Hydrologic trends| real (physical) or perceived (statistical)| suggest that water management be predicated on the assumption of hydrologic nonstationarity. The assumption leaves open the question to what extent will the ''trends'' be sustained locally and regionally over the future 25| 50 or 100 years corresponding to the economic time horizons of water projects. Whether hydrologic trends are real or perceived| record events of hydrologic extremes| floods and droughts| will be broken with exceedingly high probabilities over the economic lives of water projects. Before the assumption of hydrologic nonstationarity is accepted| the ability to cope with the uncertain impacts of global warming on water management via the operational assumption of hydrologic stationarity should be carefully examined. In the absence of strong physical evidence| trends cannot be unequivocally distinguished from slow oscillations. Slow oscillations can be mimicked by persistence in stationary processes. It is time to examine the relative merits of the assumptions of stationarity and nonstationarity in the operational context of water management. The strategy of wait-and-see| i.e. delaying the making of important| expensive and essentially irreversible capital investments| could served water managers well in coping with the uncertainties regarding climate change. 2396,1997,4,4,Students' understanding of climate change: Insights for scientists and educators,Teachers and meteorologists are among the most respected purveyors of scientific information to the public. As such| they can play an influential role in educating the public about basic atmosphere-related phenomena. To better full-fill this educational role| it is necessary to (i) identify and (ii) correct people's major misconceptions about climatic and atmospheric issues| including global climate change. This paper reports the results of a survey of high school students' knowledge and attitudes about climate change. The authors use open-ended survey questions to gain a more comprehensive understanding of the range of ''mistakes'' that are made. The results show misconceptions including inflated estimates of temperature change| confusion between ozone depletion and global warming| the perception of warmer weather and a belief that all environmentally harmful acts cause climate change. Also discussed is the origin of these mistakes from the perspective of current social scientific literature. It is suggested that these misconceptions arise from low levels of information| reliance on the televised news media| use of judgmental heuristics| confusion between weather and climate| and ''fuzzy environmentalism|'' wherein students perceive disparate environmental harms as significantly interrelated. The study also reveals that students have a very high level of trust in scientists and teachers. This suggests a role for scientists and educators through which they help correct misconceptions about climate change and ensure that people adopt effective environmentally protective measures. 4692,1997,2,4,Temperature and the life-history strategies of sea turtles,1. Sea turtles have a high fecundity| high mortality| great longevity life history strategy. 2. With the exception of the leatherback| turtle distribution is constrained by the 20 degrees C surface isotherm. 3. All sea turtles exhibit temperature-dependent sex determination (TSD) with pivotal temperatures close to 29 degrees C. 4. It is suggested that hatchling sex ratio will vary chaotically because of TSD. 5. Because of TSD and natal homing| sea turtles are likely to be adversely affected by global warming. 6. TSD and global warming have implications for conservation/management of sea turtles. (C) 1998 Elsevier Science Ltd. All rights reserved. 4869,1997,2,4,Temperature increase and its effect on microbial biomass and activity of tropical and temperate soils,Microbial biomass and activity of tropical and temperate soils from Brazil and England| respectively| were measured during 150 days incubation at 15 degrees C and 35 degrees C. Extractable carbon was determined by the fumigation-extraction method giving initial biomass values ranges from 160-600 mu g C.g(-1) soil for tropical soils and from 400-1300 mu g C.g(-1) soil for temperate soils. It was evident from all soils (except a tropical one) that biomass at 35 degrees C decreased more| over a long incubation period| than at 15 degrees C; the temperate soils had the highest decrease at 35 degrees C. Death rate of biomass quotient (go) calculated over the 150 days period of incubation showed that tropical and temperate soils| at 15 degrees C| have similar values| but at 35 degrees C temperate soils had higher rates than tropical soils| confirming the existence of some sensitivity of temperate soils to elevated temperature. Carbon from carbon dioxide (CO2-C) was also measured for all soils investigated. There was a greater respiration rate at 35 degrees C than at 15 degrees C for all the soils. The temperate soils showed faster mineralization rate than the tropical| mainly at 35 degrees C. At this temperature the amounts of CO2-C respired were from 2 to 9 times as much carbon as was present in the original biomass| indicating that this carbon could only have come from the soil organic matter. Biomass specific respiration rate (mg CO2-C evolved.g(-1) biomass.day(-1)) showed greater values for temperate soils at both temperatures| at 15 degrees C the rate was 2.7 times greater and at 35 degrees C the rate was 2.4 times greater. These results suggest that there is more available energy| in the temperate soils than in the tropical soils| reinforcing that there is more carbon stored in microbial biomass of temperate soils. Comments are made on a possible contributionof microorganisms| mainly of temperate soils| to global warming| in case of a global atmospheric temperature elevation. However| it is important to consider other factors inherent to soil characteristics (i.e. organic matter added to soil| its plant cover| soil erosion| deforestation and climatic changes) as possibly stronger causes of global warming. 4852,1997,2,4,Temperature| humidity and precipitation variations in Argentina and the adjacent sub-antarctic region during the present century,The problem regarding a possible warming in Argentina and in the adjacent sub-antarctic region has been studied within the framework of the global warming issue and taking into account the evolution of the global mean surface temperature since 1880. For this reason| the decadal averages of the annual means of the maximum| minimum and daily mean temperature| the vapor pressure and the precipitation corresponding to the periods of 1941-1950 and 1981-1990 have been compared for representative meteorological stations. The decade of 1941-1950 was chosen as a reference one as it is the warmest decade of the period of 1901-1950 in the Argentine Pampa and Chaco plains. Then| the annual mean temperature series and the annual precipitation series from representative stations of the Argentine geographical regions have been analysed. The results of these studies indicate a significant warming in southern Patagonia and South Orkney Islands since the forties or earlier| with the augmentation of each of three temperature parameters being larger than 1 degrees C. North of about 42 degrees S| however| no warming has been observed. Here| mean extreme temperatures vary in opposite directions: the mean maximum temperature decreases| while the mean minimum temperature increases. This behavior is consistent with that of the vapor pressure and the precipitation which - north of 40 degrees S - have increased since the forties. As to the sub-antarctic region in particular| the augmentation of the precipitation observed in Base Orcadas station (South Orkney Islands)| which proved to be significant at the confidence level of 1%| may be partially associated with the general warming in that region. 4783,1997,4,4,Temperature-controlled open-top chambers for global change research,To enable experiments on the interactive effects of elevated atmospheric CO2 and increased air temperature on physiological processes in trees to be carried out| we altered the standard design of open-top chambers by replacing blowers with evaporative coolers and in-line heaters| with a feedback control system to maintain ambient or elevated air temperatures within the chambers. Ambient and elevated (+ 4 degrees C) temperature regimes were attained consistently and reliably throughout the growing season| with high reproducibility between chambers. From May through December the average of nearly 300|000 temperature measurements was 18.5 degrees C in ambient air| 18.9 +/- 0.6 degrees C in six ambient chambers| and 22.4 +/- 0.9 degrees C in six elevated temperature chambers. The difference in soil temperature between ambient and elevated chambers was 1.2 degrees C. Absolute humidity (vapour pressure) in the chambers was higher than that of ambient air| but it was generally similar between temperature treatments. Vapour pressure deficit therefore was higher in elevated temperature chambers than in ambient chambers| and this difference is considered an inseparable part of the temperature treatment. The addition of a temperature control system to open-top chambers removes what has been an important flaw in this important tool for global change research. 4779,1997,2,4,The 1995 Chicago heat wave: How likely is a recurrence?,The deadly heat wave of July 1995 that affected much of the U.S. midwest| most notably Chicago| Illinois| has been put into historical perspective. The heat wave has been found to be remarkably unusual| but only partially because of the extreme high apparent temperatures (an index of the combined effect of temperature and humidity on humans)| when the authors calculate a return period of the peak apparent temperature of less than or equal to 23 yr. Of greater significance were the very high temperatures that persisted day and night over an extended 48-h period. Analysis presented here indicates that for Chicago such an extended period of continuously high day and night apparent temperature is unprecedented in modem times. The 2-day period where the minimum apparent temperature failed to go below 31.5 degrees C (89 degrees F) is calculated to be an extremely rare event (probability of occurrence < 0.1%) based on a 10 000-yr-long simulation of a four-parameter (temperatures related to the mean| the intraseasonal daily variance| the interannual variance| and the day-to-day persistence of temperature) probabilistic model. Such unusual heat waves evoke questions related to the future course of the climate and whether this recent event was merely an extreme anomaly or part of an ongoing trend toward more extreme heat waves. A Monte Carlo analysis of trends (1948-95) for various quantiles of the hourly apparent temperatures during the most severe heat waves each year from 26 midwestern stations reveals a modest| statistically insignificant increase of apparent temperatures for a wide range of quantiles without the inclusion of 1995 data. There is a statistically significant increase in apparent temperature with its inclusion| reflected most strongly for upper quantiles or daytime temperatures. It is argued| however| that because of the impact of changes in instrumentation at primary National Weather Service stations| the potential affects of urbanization| and little trend of summer mean temperatures| it is unlikely that the macroscale climate of heat waves in the Midwest or in Chicago is changing in any significant manner. Trends notwithstanding| the authors demonstrate the difficulty associated with projecting changes in the frequency and severity of similar types of events| even if the mean apparent temperature could be accurately predicted for the next century| for example| global warming projections. This is demonstrated using Chicago temperatures. The authors show that accurate projections of the frequency| severity| and duration of heat waves in the Midwest require accurate projections not only of the mean| the interannual variance| the intraseasonal variance| and day-to-day persistence| but also the interrelationships among these quantities within different synoptic-climatic regimes. 4784,1997,5,4,The borehole temperature record of climate warming in the mid-continent of North America,Ground-surface temperature (GST) histories| determined from a carefully selected set of twenty-nine borehole temperature profiles| show a warming trend over the last century that increases systematically with latitude in the mid-continent of North America. Except one site in north Texas| the borehole locations lie within a 500 x 1000 km transect that extends from the Kansas-Nebraska border into southern Manitoba. Ground-surface warming during the last century increases from + 0.4 degrees C at 41.1 degrees N to + 2.0 degrees C at 49.6 degrees N. Surface air temperature (SAT) warming in the transect| determined from Historical Climatology Network stations| increases from + 0.5 degrees C per century at 40 degrees N to + 1.6 degrees C per century at 48.8 degrees N. These warming trends agree with the regional warming pattern predicted by GCM simulations of global warming. However| the magnitudes of warming determined from the GST and the SAT data agree in regions where seasonal ground freezing does not occur but differ significantly when seasonal ground freezing does occur| Analysis of ground and air temperature coupling suggests that the greater warming observed in the GST histories in seasonally frozen ground is due to a secular increase in soil moisture that corresponds with increased precipitation during the past 50 years. (C) Elsevier Science B.V. All rights reserved. 2398,1997,4,4,The chemistry of the polluted atmosphere over Europe: Simulations and sensitivity studies with a regional chemistry-transport-model,A model environment has been established| which allows an estimation of the influence of global climate change on the chemistry of the polluted atmosphere over Europe. For this purpose the regional chemistry-transport-model of the EURAD-system has been modified and made adaptable for input data from a regional climate model| which is nested in a global atmospheric circulation model. Thus| the dynamical aspect of a possible global temperature increase as well as enhanced water vapour concentrations and background concentrations of carbon monoxide and methane can be considered. By substituting the meteorological driver model the main problems arise from different vertical grids and physical parameterization Schemes. In particular| the parameterization of cloud processes has to be checked to avoid inconsistencies between the chemistry-transport-model and its meteorological driver model. As the length of a simulation period is mainly limited by the large amount of computer| time spent for the determination of chemical transformation rates| the gas-phase chemistry module has been optimized concerning computer time and numerical stability. For validation studies of the new model system two episodic simulations were investigated| one for a summer photo-oxidants period in July 1990| the other one for January 1991. (C) 1997 Elsevier Science Ltd. 4867,1997,3,3,The costs and benefits of mitigation: A full-fuel-cycle examination of technologies for reducing greenhouse gas emissions,Comparison of options for reducing greenhouse gas emissions must take account of many different matters in a consistent manner. A method of full-fuel-cycle analysis has been developed with this aim in mind. In this method| technical options are compared using a measure made up from the ''private costs'' of owning and operating a power station together with the ''external costs'' representing its environmental impact. The method is tested on three types of power generation plant| each of which incorporates CO2 capture and sequestration technology - these include natural gas-fired and coal-fired power plant| as well as CO2 storage in a disused gas field| in the deep ocean or in an off-set forest. Emissions arising from all stages of the fuel cycle are estimated - from extraction of fossil fuel through to dispatch of power to the grid. All types of emission and their impact at local| regional and global level are assessed and valuation of these impacts is attempted. Previous work in this field has concentrated on local impacts| such as occupational health| and regional impacts| such as ''acid rain''. This study is one of the first to include a comprehensive assessment of global warming impacts| how these will vary with time as well as geographically| including allowance for any potential benefits. From this| the environmental external costs of the fuel cycles are determined. (C) 1997 Elsevier Science Ltd. 4815,1997,3,4,The decomposition of forest products in landfills,Large quantities of forest products are disposed of in landfills annually. The fate of this vast pool of carbon is important since carbon sequestration and the generation of landfill gases have important implications for global warming. Published estimates of methane yields were used to estimate the amount of carbon released into the atmosphere from landfilled forest products. These calculations suggest that maximally only 30% of the carbon from paper and 0-3% of the carbon from wood are ever emitted as landfill gas. The remaining carbon| approximately 28 Tg in 1993| remains in the landfill indefinitely. Some of this carbon may be removed during leachate treatment| but a large portion is permanently sequestered when its impact on global warming is negligible. The placement of forest products in landfills serves as a significant carbon sink| and its importance in the global carbon balance should not be overlooked. Published by Elsevier Science Limited. 4855,1997,4,3,The discovery of the risk of global warming,It is now a century since S^ante Arrhenius published the idea: As human activity puts ever more carbon dioxide into the atmosphere| global warming becomes ever more likely. (See figure 1 and the box on page 36.) His paper attracted notice| and one might suppose that knowledge of the so-called "greenhouse effect" has grown steadily ever since.1 But that is not in fact how the science proceeded. During more than half a century after 1896 almost nothing of value was learned about global warming. Only in the late 1950s did scientists at last begin to regard it as a serious possibility| indeed a potential danger.
Not that climate change itself had been ignored; even the general public paid attention to that. By the late 1930s it was common knowledge that the world had been warming up. Grandfathers were saying that the younger generation had it easy: none of those early frosts and daunting blizzards of bygone times. And in fact| as one magazine put it in 1951| "The old-timers are right—win- ters aren't what they were." The evidence was largely anecdotal. Rivers failed to freeze over as formerly| glaciers retreated| and fish were found north of their former haunts. But detailed analysis of temperature statistics also seemed undeniably to show a rise.2 (See figure 2.)
Nobody was worried. It seemed reasonable that weather moves in cycles| temperatures rising and falling slightly over decades and centuries. If we happened to be in for a spell of warming| so much the better! A Saturday Evening Post article was typical in supposing that "vast new food-producing areas will be put under cultivation farther north." Such talk attracted little in- terest| for it was merely speculation about some remote future century. And as Time magazine said| "Meteorolo- gists don't know whether the present warm trend is likely to last 20 years or 20|000 years."3
By the early 1960s much had changed. Many scien- tists had become seriously concerned that warming might be no mere phase of a modest natural cycle but the onset of an accelerating climb| unprecedented and foreboding. This shift of understanding and attention may eventually be regarded as one of our century's pivotal scientific developments. Yet as we shall see| it was largely a matter of luck—a byproduct of work aimed at entirely different questions.
The reality of the decreasing global irradiation of more than 0.5 Watt per m(2) annually since the early 50s at the one hand and the augmenting of the green house forcing at the other hand contradict the existing models and the forcasts on global warming. The question regarding the cause of the remarkable decrease of the global irradiation still has to be answered! Two hypothetical attempts for an explanation - additional reflexion and/or absorption of solar irradiation in the atmosphere - are in discussion. The causes have to be sought in the atmosphere of the earth and by the human activities since the 50s. Concluding may be stated that at present there are two opposite climatological processes on the way. The decreasing global irradiation contra the augmentation of the green house forcing. Still it has to be remembered that an increasing green house forcing depends fundamentaly on the amount of the global irradiation. An increasing green house forcing can surely only compensate for a restricted time scale a decrease of the global irradiation. It seems a very alarming vision that the human activities mainly since the 50s cause a global cooling up from the time space when the green house forcing can not compensate the decrease of the global irradiation anymore. In the future modelers and forecasters of climate change must consequently attache more importance to the reality of the wide-spread decreases of the global irradiation over the whole atmosphere presumable caused by aerosols and clouds in releation to the augmenting climate forcings caused by increasing concentrations of green house gases in the atmosphere.
4876,1997,3,3,What is the value of scientific knowledge? An application to global warming using the PRICE model,Governments must cope with the enormous uncertainties about both future climate change as well as the costs and benefits of slowing climate change. This study analyses the value of improved information about a variety of geophysical and economic processes. The value of information is estimated using the ''PRICE model'' which is a probabilistic extension of earlier models of the economics of global warming. The study uses five different approaches to estimating the value of information about all uncertain parameters and about individual parameters. It is estimated that the value of early information is between $1 and $2 billion for each year that resolution of uncertainty is moved toward the present. We estimate that the most important uncertain variables are the damages of climate change and the costs of reducing greenhouse gas emissions. Resolving the uncertainties about these two parameters would contribute 75 percent of the value of improved knowledge. 2383,1997,4,4,Why regional studies are needed in the development of full-scale integrated assessment modelling of global change processes,Full-scale integrated assessment models (IAMs) allow many components of the global climate change problem to be examined in one framework. The chief advantage of the IAM approach over less complete modelling frameworks is that the socio-economic and environmental consequences of policy choices aimed at abating or adapting to climate change can be evaluated in their totality| However| the highly aggregate functional forms that IAMs currently embed are lacking in sufficient regional and sectoral detail to be totally credible. In this paper| ten reasons why regional studies are needed in support of the development of full-scale IAMs are given. A strategic cyclical scaling exercise involving regional and global integrated modelling frameworks is proposed| (C) 1997 Elsevier Science Ltd. All rights reserved. 2387,1997,2,3,Wildlife and climate change: Assessing the sensitivity of selected species to simulated doubling of atmospheric CO2,We explored| using computer simulations| the sensitivity of four mammal species (elk| Cervus canadensis; white-tailed deer| Odocoileus virginianus; Columbian ground squirrel| Spermophilus columbianus; and chipmunk| Tamias striatus) within the continental USA to the effect of anticipated levels of global climate change brought about by a doubling of atmospheric CO2. Sensitivity to the direct effects of climate change were evaluated using a climate-space approach to delineate the range of thermal conditions tolerable by each species. Sensitivity to indirect effects were evaluated by quantifying the association of each species to the current vegetation distribution within the continental USA and using this association to assess whether wildlife species distributions might shift in response to vegetation shifts under climate change. Results indicate that altered thermal conditions alone should have little or no effect on the wildlife species' distributions as physiological tolerance to heat load would allow them to survive. Analyses of the effects of vegetation change indicate that deer and chipmunks should retain their current distributions and possibly expand westward in the USA. For Elk and ground squirrels| there is a possibility that their current distributions would shrink and there is little possibility that each species would spread to new regions. This work emphasizes that the distributions of the four mammalian species are likely to be influenced more by vegetation changes than by thermal conditions. Future efforts to understand the effects of global change on wildlife species should focus on animal-habitat and climate-vegetation linkages. 4853,1997,2,4,Winter storms in Switzerland north of the Alps 1864/1865-1993/1994,In the framework of the Swiss National Research Program 31 ''Climate changes and natural disasters'' the question was brought up whether a global warming of the atmosphere would have an influence on the frequency and/or intensity of the extratropical storms of the Swiss winter season. In order to investigate a possible trend| time series of days with a minimum wind speed estimate or measurement equivalent to Beaufort 7| 8 and 9 were established. The longest being a record of the mesonet station Zurich from the period 1864 until 1993 (130 years). Slightly shorter time series for three additional stations in Northern Switzerland were compiled to control the behavior of the longest record and to verify the observed temporal trend. From the location of the four investigated wind records the observational domain was restricted to the part of Switzerland north of the Alps whereas for further meteorological considerations the whole North-Atlantic-European area was included. A negative regional trend in the number of storm days has been observed during the last century. In particular| the period before 1940 has to be interpreted as windier than the following decades. The duration of a storm event also decreased on average. In spite of an increase in cyclonic westwind situations since about 1960 over Europe| Switzerland was hit by fewer storms during the same period. One explanation could be that the whole westwind belt has moved slightly further north where a deepening of the cyclones was observed in recent times. Switzerland is usually situated at the southernmost edge of the particular storm fields and is therefore less influenced by strong gales. Rare exceptions are the cases when a secondary depression directly hits Central Europe| e.g. as happened in February 1990 (storm ''Vivian''). 4887,1997,4,4,Wintertime measurement of the greenhouse radiation from nitrous oxide,Ground-based| thermal emission measurements of the cold| clear sky have been made and showed several emission bands in the mid-infrared region that are associated with nitrous oxide (N2O). A spectrum of the background atmospheric emission in the absence of any N2O has been simulated using the FASCD3P line-by-line radiation code with measured radiosonde parameters of pressure| temperature and relative humidity. The simulated spectrum has been used to extract the thermal emission bands of N2O from the total atmospheric emission spectrum. It teas determined that incorporating an N2O mixing ratio of 316 +/- 35 ppbv in the simulations provided excellent agreement with the measured radiance. The downward greenhouse flux at the surface associated with the 1100-1350 cm(-1) bands of N2O was measured to be 0.80 W/m(2) +/- 12% for cold winter conditions. The flux for all the infrared bands of N2O has been estimated to be 1.43 W/m(2) +/- 12%. 4847,1997,3,4,Wood density for estimating forest biomass in Brazilian Amazonia,Reliable estimates of the biomass of Amazonian forests are needed for calculations of greenhouse gas emissions from deforestation. Interpretation of forest volume data for the region is the most practical means of obtaining representative biomass estimates| The density of the wood used in converting volume data to biomass is a key factor affecting estimates of biomass and of emissions. Interpreting density data for biomass purposes| which is different from the normal use of these data for commercial timber uses| is complicated by a variety of factors. There is variability among individuals of a given species| among geographic locations| and within the vertical and radial dimensions of individual trees. Considerable confusion has resulted from the variety of ways that densities are reported with respect to humidity at time of the weight and volume measurements used in calculating the density value. The most appropriate measure for biomass is basic density| or oven-dry weight divided by wet volume. Corrections for hollow trees and the position of samples within trunks are also needed. Here| available data are brought together for 268 species of trees| with an unweighted mean basic density of 0.65 (range 0.14-1.21). Weighting the mean by the volume of wood of each species in a sample of vegetation types| and weighting the means of the vegetation types by the extent of each in the region| yields a mean density of 0.69. Although the weighted mean density calculated here has a much firmer empirical basis than previously available estimates for this parameter| uncertainty is still considerable| particularly as a result of doubt concerning taxonomic identifications in the forestry surveys. Were the wood density of a small but botanically well-studied plot near Manaus to apply to the region as a whole| Brazil's 1990 emissions of greenhouse gases would be higher by an amount equivalent to two-thirds of the country's annual emission from fossil fuels. 2403,1997,2,4,World food markets into the 21st century: environmental and resource constraints and policies,Projections of global food supply and demand to the year 2020 indicate that food production in the aggregate is likely to keep pace with growing populations and incomes| and that real food prices will be stable or slowly declining. This article examines the possible environmental and resource constraints to long-term food production growth and explores the implications of these possible constraints for food and resource policies. The article reviews and synthesises the evidence on biophysical limits to crop productivity; plant genetic resources and biotechnology; the availability of plant nutrients; soil and land degradation; the increasing scarcity and declining quality of water; and the impact of global climate change on agriculture. 4523,1998,3,3,A "green" route to adipic acid: Direct oxidation of cyclohexenes with 30 percent hydrogen peroxide,Currently| the industrial production of adipic acid uses nitric aid oxidation of cyclohexanol or a cyclohexanol/cyclohexanone mixture. The nitrous oxide emission from this process measurably contributes to global warming and ozone depletion. Therefore| the development of an adipic acid production process that is Less damaging to the environment is an important subject in chemical research. Cyclohexene can now be oxidized directly to colorless crystalline adipic acid with aqueous 30 percent hydrogen peroxide under organic solvent- and halide-free conditions| which could provide an ideal solution to this serious problem. 4580,1998,4,4,A 'Richter scale for risk'? Scientific management of uncertainty versus management of scientific uncertainty,There have recently been calls in the UK for the development of a 'Richter scale for risk'. It is helpful when considering the merits of these proposals to distinguish three categories of risk: directly perceptible risk| e.g. climbing a tree| riding a bicycle; risks perceptible with the help of science| e.g| cholera and other infectious diseases; and virtual risks| about which scientists do not know or can not agree| e|g. BSE/CJD and suspected carcinogens. The professional management of directly perceptible risks is made difficult and frustrating by people insisting on being their own risk managers| and overriding the judgements of risk experts and the interventions of safety regulators. Risks perceived through science are framed in terms of probabilities. The Richter scale for risk seeks| by means of a table of 'benchmark risks'| to help scientists communicate their knowledge of risk to the lay public. But frequently these probabilities are nothing but confident sounding expressions of uncertainty. We do not respond blankly to uncertainty; we impose meanings upon it| and act upon these meanings. Virtual risks may or may not be imaginary - but they hare real consequences. The diverse responses to the inconclusive scientific evidence about issues such as BSE;| pesticide residues| low level radiation| and global warming indicate that virtual risks are perceived through different cultural filters. The incoherent and inconclusive debates about such issues suggest the need for a better understanding of these fillers. 4656,1998,4,1,A Bayesian statistical analysis of the enhanced greenhouse effect,This paper demonstrates that there is a robust statistical relationship between the records of the global mean surface air temperature and the atmospheric concentration of carbon dioxide over the period 1870-1991. As such| the enhanced greenhouse effect is a plausible explanation for the observed global warming. Long term natural variability is another prime candidate for explaining the temperature rise of the last century. Analysis of natural variability from paleo-reconstructions| however| shows that human activity is so much more likely an explanation that the earlier conclusion is not refuted. But| even if one believes in large natural climatic variability| the odds are invariably in favour of the enhanced greenhouse effect. The above conclusions hold for a range of statistical models| including one that is capable of describing the stabilization of the global mean temperature from the 1940s to the 1970s onwards. This model is also shown to be otherwise statistically adequate. The estimated climate sensitivity is about 3.8 degrees C with a standard deviation of 0.9(degrees) C| but depends slightly on which model is preferred and how much natural variability is allowed. These estimates neglect| however| the fact that carbon dioxide is but one of a number of greenhouse gases and that sulphate aerosols may well have dampened warming. Acknowledging the fact that carbon dioxide is used as a proxy for all human induced changes in radiative forcing brings a lot of additional uncertainty. Prior knowledge on both climate sensitivity and radiative forcing is needed to say anything about the respective sizes. A fully Bayesian approach is used to combine expert knowledge with information from the observations. Prior knowledge on the climate sensitivity plays a dominant role. The data largely exclude climate sensitivity to be small| but cannot exclude climate sensitivity to be large| because of the possibility of strong negative sulphate forcing. The posterior of climate sensitivity has a strong positive skewness. Moreover| its mode (again 3.8 degrees C; standard deviation 2.4 degrees C) is higher than the best guess of the TPCC. 4508,1998,3,3,A carbon arc process for treatment of CF4 emissions,Light perfluorocarbons| such as carbon tetrafluoride| are produced or emitted from a Variety of processes| including manufacture of aluminum and processing of semiconductor devices. At the same time| the long atmospheric lifetime and high global warming potential of such compounds makes them an environmental concern. A new process far the abatement of perfluorocarbon emissions using a carbon are plasma was investigated| in particular| the conversion of CF4 to C2F4 and higher fluorinated species| including poly(tetrafluoroethylene) (PTFE) was demonstrated. General features of the reaction chemistry are discussed| including primary reactions to form radicals and ions and secondary reactions to form C2F4 and higher compounds. The conversion efficiencies and products obtained in the reported experiments indicate potential applicability of the process for point source emission control of high global warming potential perfluorocarbons. 4556,1998,4,3,A climate change scenario for the tropics,This paper describes the construction of a climate change scenario for a region representing the 'extended' Tropics - 30 degrees N to 30 degrees S - using a methodology that combines results from a simple climate model and a Global Climate Model (GCM) transient climate change experiment. The estimated date by which this climate change scenario might be realized ranges from as early as the end of the 2030s to as late as well into the 22nd century. The central estimate is for this scenario to describe the climate of the 2060s| which would represent a global warming rate of about 0.2 degrees C per decade| with associated atmospheric CO2 concentrations estimated to be about 560 ppmv| 55% higher than 1990 levels. The role of anthropogenic aerosols in offsetting part of this future global warming and altering the regional character of the changes has not been considered. The paper presents changes in mean temperature; mean rainfall; rainfall seasonality| variability| frequency| and intensity and soil moisture. These patterns of change derive from only one GCM climate change experiment; different experiments would yield different patterns for the same global warming. There is also some discussion about possible changes in tropical cyclone (TC) activity| although since TCs remain poorly modelled in GCMs| the full range of possibilities (from reduced activity| through no change| to increased activity) should be considered in any impact assessment. 4605,1998,4,3,A common-sense climate index: Is climate changing noticeably?,We propose an index of climate change based on practical climate indicators such as heating degree days and the frequency of intense precipitation. We find that in most regions the index is positive| the sense predicted to accompany global warming| In a few regions| especially in Asia and western North America| the index indicates that climate change should be apparent already| but in most places climate trends are too small to stand out above year-to-year variability. The climate index is strongly correlated with global surface temperature| which has increased as rapidly as projected by climate models in the 1980s| We argue that the global area with obvious climate change will increase notably in the nest few years. But we show that the growth rate of greenhouse gas climate forcing has declined in recent years| and thus there is an opportunity to keep climate change in the 21st century less than "business-as-usual" scenarios. 2349,1998,2,4,A look at global tropical cyclone activity during 1995: Contrasting high Atlantic activity with low activity in other basins,During 1995| there was a near-record number of named tropical cyclones in the North Atlantic basin. This unusual event fueled speculation that it marked a tangible signal of global:climate change| or that it marked a return to a period of higher tropical cyclone activity in the Atlantic| such as that which has been documented to have occurred during the decades of the 1940s through the 1960s. Less publicized| the tropical cyclone activity in other basins during 1995 was almost everywhere below normal. The concept of global and basin "prolific" years and "meager" years is introduced. During the past 30 years| the Atlantic has had two prolific years: 1969 and 1995. Although the annual number of tropical cyclones in each of the other basins is uncorrelated with the annual number of tropical cyclones in the Atlantic| the two Atlantic prolific years of 1969 and 1995 were meager years in some of the other major basins| and below normal years in all of them. In the time series of the annual number of tropical cyclones in all basins except the Atlantic| 1969 and 1995 rank lowest and third lowest| respectively. The known relationships of the annual number of tropical cyclones in the Atlantic with ENSO and with the quasi-biennial ossilation are insufficient to explain the unusual global distribution of tropical cyclones during 1995. 4653,1998,2,4,A model for the influence of the greenhouse effect on insect and microorganism geographical distribution and population dynamics,A model for the influence of the greenhouse effect on insect and microorganism geographical distribution and population dynamics using cellular automata is presented. Based on this model| an algorithm has been developed and used to determine the geographical distribution and population dynamics of a hypothetical species in an scenario of global warming. The species' initial population distribution is assumed to be Gaussian. After the initiation of global warming| the population moves and after a few decades the population distribution is no longer Gaussian. Larger populations are found in the direction of population movement. (C) 1998 Elsevier Science Ireland Ltd. 2370,1998,2,2,A modeling approach to simulate impact of climate change in lake water quality: Phytoplankton growth rate assessment,Global climate change induced by increased concentrations of greenhouse gases (especially CO2) is expected to include changes in precipitation| wind speed| incoming solar radiation| and air temperature. These major climate variables directly influence water quality in lakes by altering changes in flow and water temperature balance. High concentration of nutrient enrichment and expected variability of climate can lead to periodic phytoplankton blooms and an alteration of the neutral trophic balance. As a result| dissolved oxygen levels| with low concentrations| can fluctuate widely and algal productivity may reach critical levels. In this work| we will present: 1) recent results of GCMs climate scenarios downscaling project that was held at the University of Derby| UK.; 2) current/future comparative results of a new mathematical lake eutrophication model (LEM) in which output of phytoplankton growth rate and dissolved oxygen will be presented for Suwa lake in Japan as a case study. The model parameters were calibrated for the period of 1973-1983 and validated for the period of 1983-1993. Meteorologic| hydrologic| and lake water quality data of 1990 were selected for the assessment analysis. Statistical relationships between seven daily meteorological time series and three airflow indices were used as a means for downscaling daily outputs of Hadley Centre Climate Model (HadCM2SUL) to the station sub-grid scale. (C) 1998 IAWQ. Published by Elsevier Science Ltd. 4524,1998,4,4,A modelling methodology for assessing the impact of climate variability and climatic change on hydroelectric generation,A new methodology relating basic climatic variables to hydroelectric generation was developed. The methodology can be implemented in large or small basins with any number of hydro plants. The method was applied to the Sacramento| Eel and Russian river basins in-northern California where more than 100 hydroelectric plants are located. The final model predicts the availability of hydroelectric generation for the entire basin provided present and near past climate conditions| with about 90% accuracy. The results can be used for water management purposes or for analyzing the effect of climate variability on hydrogeneration. Climate change scenarios were defined to investigate the impact of global warming on the hydrogeneration availability in the basin. A wide range of results can be obtained depending on the climate change scenario used. (C) 1998 Elsevier Science Ltd. All rights reserved. 4590,1998,2,4,A monthly streamflow model,To estimate the potential consequences of projected global warming on streamflow| a deterministic model for a monthly timescale has been developed. The model structure is based on the water budget theory and contains deterministic relationships to estimate four components of streamflow: direct runoff| interflow| base flow| and snowmelt. The model inputs are six climate variables for each time step and 10 watershed parameters. The model has four calibration parameters which are related to direct runoff and snowmelt runoff. The model has been applied to the Little Washita River watershed in Oklahoma and the Baptism River watershed in Minnesota. The former is an agricultural watershed with a warm and seasonally dry climate| and the latter is a forested watershed with a cool and humid climate. The model simulates mean monthly streamflow in the Baptism River with a Nash-Sutcliffe coefficient (NSC) of 0.99 and a correlation coefficient of 0.83. For the Little Washita River the same simulation measures are 0.94 and 0.89| respectively. 4670,1998,3,3,A review of carbon and nitrogen balances in switchgrass grown for energy,Increased atmospheric CO2| caused partly by burning fossil fuels| is assumed to elevate the risk of global warming| while nitrate contamination of surface runoff and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration| and reduce NO3-1 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in filter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature| unpublished data and on-going research. Replacing fossil fuels with switchgrass| or any other biomass| will have a much greater effect on atmospheric CO2 than C sequestration. This is because replacing fossil fuels provides a cumulative effect| while C sequestration offers only a one-time benefit. Furthermore| switchgrass will provide net gains in C sequestration only if it replaces annual row crops| but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%| which compares favorably with the 50% recovery frequently quoted as the norm for wheal (Triticum aestivum L.) and corn (Zea mays L). (C) 1998 Elsevier Science Ltd. All rights reserved. 4591,1998,2,3,A simple method to estimate the potential increase in the number of generations under global warming in temperate zones,The Intergovernmental Panel on Climate Change (IPCC) estimated that the global mean surface air temperature will increase about 2 degrees C above the 1990 level by 2100. Such an increase in temperature may result in an increase in the number of generations per year of most insects. Several simulation models have been constructed to predict the increase in the number of generations| but these require a great deal of calculation to obtain estimates for many insect species at various locations under various scenarios of global warming. This paper proposes an analytical method to enable a quick estimation. Two assumptions are used: (1) The developmental rate of insects is approximately given by a linear function of temperature (T)| with a developmental zero (T(0)) and a thermal constant (K). (2) The increase in temperature is approximately even throughout the year. Let m be the current annual mean temperature at a given location| and Delta T the potential increase in temperature under global warming at the location. If the temperature before the Delta T-rise is higher than T(0) in summer and lower than (T(0)-Delta T) in winter| the increase in the number of generations per year| which is denoted by Delta N| is approximately given by Delta N approximate to Delta T[c + d(m - T(0))]/K| where c and d are constants. The validity of the approximation is checked using the "smoothed daily normals" in Japan obtained as a running mean of 15 successive daily normals where a daily normal is defined as the averaged daily temperatures for 30 years from 1960 to 1990. The estimates are c=204.4 and d=12.46. Using this formula| linear isoclines of Delta N are plotted in a graph of T(0) versus K. By plotting the T(0) and K of various insects in this graph| we can estimate the increase in the number of generations under global warming in temperate zones. 4572,1998,4,3,A stochastic model of global atmospheric response to enhanced greenhouse warming with cloud feedback,An atmosphere-ocean climate box model is used to examine the influence of cloud feedback on the change in the climate system's variability in response to enhanced greenhouse warming. The model consists of three nonlinear stochastic differential equations that are simplified forms of the first law of thermodynamics for the atmosphere and ocean and the continuity equation for the atmospheric component of the hydrological cycle. The model is driven by random fluctuations in the mean evaporative flux| which is routed and distributed among the components of the system through the fluxes of energy and moisture. The model suggests that cloud feedback can lead to the occurrence of two climatic regimes into which the present climate may evolve as a result of an enhanced greenhouse warming. In the first regime| the mean values of the model parameters| such as temperature| precipitation and cloudiness| as well as the amplitude and timescale of their fluctuations all increase moderately. In the second regime these mean values increase substantially| and the amplitude and timescale of their fluctuations rise sharply. The model also predicts the existence of climatic hysteresis; that is| for the climate system to return from either of these regimes back to the present regime| a substantial decrease in the long-wave forcing is required. (C) 1998 Elsevier Science B.V. All rights reserved. 4487,1998,3,3,A worldwide perspective on energy| environment and sustainable development,Problems with energy supply and use are related not only to global warming| but also to such environmental concerns as air pollution| ozone depletion forest destruction and emission of radioactive substances. These issues must be taken into consideration simultaneously if humanity is to achieve a bright energy future with minimal environmental impacts. Much evidence exists which suggests that the future will be negatively impacted if humans keep degrading the environment. There is an intimate connection between energy| the environment and sustainable development. A society seeking sustainable development ideally must utilize only energy resources which cause no environmental impact (e.g. which release no emissions to the environment). However| since all energy resources lead to some environmental impact| it is reasonable to suggest that some (not all) of the concerns regarding the limitations imposed on sustainable development by environmental emissions and their negative impacts can be in part overcome through increased energy efficiency. A strong relation clearly exists between energy efficiency and environmental impact since| for the same services or products| less resource utilization and pollution is normally associated with higher efficiency processes. Anticipated patterns of future energy use and consequent environmental impact (focusing on acid precipitation| stratospheric ozone depletion and the greenhouse effect) are comprehensively discussed in this paper. Also| some solutions to current environmental issues in terms of energy conservation and renewable energy technologies are identified and some theoretical and practical limitations on increased energy efficiency are explained. The relations between energy and sustainable development| and between the environment and sustainable development| are described| and an illustrative example is presented. Throughout the paper several issues relating to energy| environment and sustainable development are examined from both current and future perspectives. Finally| several conclusions and recommendations are drawn which may be useful to energy scientists and engineers and policy makers. (C) 1998 John Wiley & Sons| Ltd. 4681,1998,3,3,Acid-base reactions leading to fouling and corrosive ionic liquids in the combustion of biomass,Modem solution theories for ionic liquids coupled with a thermodynamic database and a robust computer program for free energy minimization are capable of performing accurate calculations of the total chemistry of the combustion of biomass. The results provide a quantitative description of the chemistries and of the acid-base reactions involved and predict problems due to the formation of fouling and corrosive ionic liquids. A detailed knowledge of the acid-base chemistries involved in the formation of such ionic liquids allows one to solve such problems by the use of additives and helps to improve the efficiency of power production from biomass combustion effluents. Such efficiencies would make biomass more competitive with fossil fuels and allow one to minimize the probable influence of CO2 buildup on global warming. 2364,1998,2,4,Adaptation mechanisms of green plants to environmental stress - The role of plant sterols and the phosphatidyl linolenoyl cascade in the functioning of plants and the response of plants to global climate change,Introduction: Like other organisms| plants have to cope with environmental stress. Escape from stress is limited: Plants are immobile and cannot run away from stressful conditions. Plants may| however| survive extended periods of stress| for example| cold stress during the winter season| (i) as seed (summer annuals) or (ii) alternatively they may survive in a resting stage| dormancy| as in decidous trees or (iii) they tolerate the cold stress in a more active way| as in evergreen conifers. Environmental changes may be perceived by plants in a rather direct way or more indirectly| via signal perception/transduction pathways. As autotrophic organisms| green plants exhibit a direct response to sunlight in the form of the photosynthetic light reaction. Mechanical factors such as air movement and impedance by hard soil layers present further examples in which direct responses of plants to the environment are expected.
2376,1998,4,4,Advanced Earth observing Satellite-II (ADEOS-II): New prospects for global environmental monitoring,A survey has been made of the scientific programme and instrumentation developed for the advanced Earth observing satellite-II (ADEOS-II) to be launched in 1999| in the context;of previous efforts and future research in the fields of global change relevant to problems| such as global climate change (with special emphasis on the global energy and water cycles)| the global carbon cycle (respectively| marine and terrestrial biosphere dynamics)| high-latitude environmental dynamics| natural calamities (earthquakes| tsunami| volcanic eruptions etc.) and other environmental problems. 4634,1998,2,4,Air issues and ecosystem protection| a Canadian national parks perspective,Several case histories illustrate national park air issues and responses in Canada. These examples include: acidification studies and establishment of a multiparticipant monitoring programme at Kejimkujik; studies of smoke at campgrounds in Jasper| La Mauricie and Forillon| its effect on health| and the management of visitors and firewood supply to mitigate these risks; and estimates of emissions from through-traffic in Yoho. From these cases and from reviews of the secondary literature| we can identify air issues that affect the maintenance of ecological integrity in national parks. These issues are: forest fires and smoke management| defining goals for ecosystem restoration; representation of natural regional conditions; visitor health and amenity; acidification; pesticides; eutrophication from airborne nitrates; permafrost melting; and UV-B. In June 1995| an International Air Issues Workshop brought together representatives from Canadian and U.S.| national parks and other selected agencies. They ranked the air issues affecting national parks| producing quite an eclectic list. From the most to least serious issue| they are: acidification| toxics| visibility impairment| W-B| smoke management| oil and gas development| fugitive dust| global warming| overflights| light pollution| noise and odour. Note that atmospheric change is only one among a group of stresses affecting national parks. Of 28 stresses recognized as significant for national parks in 1992| acid precipitation ranked 8th and climate change 23rd| Petrochemicals| 17th| pesticides| 18th and heavy metals| 21st| may be partly airborne. The 1995 workshop made several recommendations applicable to Parks Canada| from which those related to research and monitoring needs have been extracted. The air monitoring needed most by national parks is of suspended particulate and visibility. This is in response to human health and amenity concerns and international treaty obligations. The long-term protection of natural sites in national parks provides opportunities for other agencies to monitor ambient air quality and ecosystem responses| for example through the installation of under-canopy monitoring towers. The air research most needed in national parks is the modelling of natural landscapes and vegetation complexes in response to climate change| This follows from the primary purpose of each national park| to maintain the ecological integrity of an area selected to represent a natural region. The principal air research opportunities for other agencies in national parks are probably intensive instrumentation and sampling over several years to examine the air-vegetation-soil transfers of nutrients| pollutants and radiation. 2321,1998,2,4,An empirical test of Rapoport's rule: Elevational gradients in montane butterfly communities,We examined the response of montane butterflies to a 1300-m elevational gradient in the Toiyabe Range| a mountain range in the central Great Basin. We tested whether elevational ranges of montane butterflies conform to Rapoport's elevational rule (species at higher elevations have greater elevational ranges). We also tested whether the Rapoport-rescue hypothesis (emigrants from higher elevation populations inflate the species richness of lower-elevation sites) could explain the species richness patterns we observed. In addition| we predicted whether global climate change is likely to perturb current elevational gradients in butterfly species richness. Species presence data were collected from 105 100-m vertical elevational bands in 17 canyons. Elevation and species richness were significantly negatively correlated| although species richness peaked at intermediate elevations| and butterflies in species-rich areas had significantly narrower elevational ranges than species in more depauperate areas. Toiyabe Range butterflies conformed to Rapoport's elevational rule. The Rapoport effect we documented did not result from sampling bias. However| the Rapoport-rescue hypothesis cannot fully explain the elevational gradient in species richness. Environmental severity at either end and favorable conditions near the middle of the elevational gradient likely contributed to high species richness at intermediate elevations. Our models indicated that few butterfly taxa will be lost from the Toiyabe Range in the face of climate change. To maintain present species richness and maximize the potential of Great Basin butterflies to adapt to rapid climate change| we recommend that habitat protection and restoration efforts target not only high elevation Wilderness Areas but also intermediate elevations. 2374,1998,2,4,An experimental and modeling study of responses in ecosystems carbon exchanges to increasing CO2 concentrations using a tropical rainforest mesocosm,The ecosystem carbon exchanges in the enclosed rainforest of Biosphere 2| an enclosed apparatus comprised of large synthetic ecosystems| were measured and modeled during the winter of 1995-1996 under different atmospheric CO2 concentrations. On eight separate days| this mesocosm was exposed to various levels of CO2 ranging from about 380 to 820 mu mol mol(-1) daily mean and then sealed 24 hours for continuous measurements of ecosystem CO2 fluxes. Our results indicated that net ecosystem carbon exchange in the mesocosm was enhanced by increasing CO2 over the short periods studied (2-7 weeks)| but| as expected from physiological studies| the response is not linear. The main effect of shortterm CO2 change was the enhancement of canopy CO2 assimilation| while soil respiration was not affected by the atmospheric CO2 concentration. The whole ecosystem radiation use efficiency was significantly higher under higher CO2. The results of direct measurements were predicted well by a simple canopy model (the 'big-leaf' model) that incorporates current physiological understanding of the biochemistry of leaf photosynthesis. Validation of this model with a range of CO2 and light levels indicates that it can be used with confidence to predict the responses of natural ecosystems to global climate change. Response of ecosystem processes to elevated CO2 with relaxation time longer than a few weeks could not be resolved in this study| but longer-term closure experiments are planned to examine these processes. 2348,1998,4,4,An ocean acoustic tomography system with a 200 Hz giant magnetostrictive source,This paper describes tomography equipment for measuring ocean phenomena in a 2000 km(2) area. A 200 Hz giant magnetostrictive source was developed to increase the transmitting level and decrease the source size. Five 200 Hz transceiver systems were constructed with these sources. These systems have surface buoys for real-time data transmission via the INMARSAT-C. Sea tests of the five transceiver systems were conducted east of the Izu-Ogasawara Trench to observe the Kuroshio Extension during July and September 1997. 4655,1998,3,4,Analysis of energy conversion systems| including material and global warming aspects,This paper addresses a method for the overall evaluation of energy conversion systems| including material and global environmental aspects. To limit the scope of the work reported here| the global environmental aspects have been limited to global warming aspects. A method is presented that uses exergy as an overall evaluation measure of energy conversion systems for their lifetime. The method takes the direct exergy consumption (fuel consumption) of the conventional exergy analyses and adds (1) the exergy of the energy conversion system equipment materials| (2) the fuel production exergy and material exergy| and (3) the exergy needed to recover the total global warming gases (equivalent) of the energy conversion system. This total| termed "Total Equivalent Resource Exergy|" (TERE)| provides a measure of the effectiveness of the energy conversion system in its use of natural resources. The results presented here for several example systems illustrate how the method can be used to screen candidate energy conversion systems and perhaps| as data becomes more available| to optimize systems. It appears that this concept may be particularly useful for comparing systems that have quite different direct energy and/or environmental impacts. This work should be viewed in the context of being primarily a "concept" paper in that the lack of detailed data available to the authors at this time limits the accuracy of the overall results. The authors are working on refinements to data used in the evaluation. 2357,1998,4,4,Analysis of some direct and indirect methods for estimating root biomass and production of forests at an ecosystem level,The relationship of global climate change to plant growth and the role of forests as sites of carbon sequestration have encouraged the refinement of the estimates of root biomass and production. However| tremendous controversy exists in the literature as to which is the best method to determine fine root biomass and production. This lack of consensus makes it difficult for researchers to determine which methods are most appropriate for their system. The sequential root coring method was the most commonly used method to collect root biomass data in the past and is still commonly used. But within the last decade the use of minirhizotrons has become a favorite method of many researchers. In addition| due to the high labor-intensive requirements of many of the direct approaches to determine root biomass| there has been a shift to develop indirect methods that would allow fine root biomass and production to be predicted using data on easily monitored variables that are highly correlated to root dynamics. Discussions occur as to which method should be used but without gathering data from the same site using different methods| these discussions can be futile. This paper discusses and compares the results of the most commonly used direct and indirect methods of determining root biomass and production: sequential root coring| ingrowth cores| minirhizotrons| carbon fluxes approach| nitrogen budget approach and correlations with abiotic resources. No consistent relationships were apparent when comparing several sites where at least one of the indirect and direct methods were used on the same site. Until the different root methods can be compared to some independently derived root biomass value obtained from total carbon budgets for systems| one root method cannot be stated to be the best and the method of choice will be determined from researcher's personal preference| experiences| equipment| and/or finances. 4658,1998,3,3,Assessing management options for wastewater treatment works in the context of life cycle assessment,This paper presents the preliminary results of a Life Cycle Assessment (LCA) study comparing different wastewater treatment works| operated by Thames Water Utilities Ltd. in the UK. Fifteen works have been studied| representing a range of size and type of treatment works. Five management regimes for centralising sludge treatment and disposal were analyzed in the context of LCA to provide guidance on choosing the best practicable environmental option (BPEO). Consideration of Global warming potential indicates that the four proposed management regimes with centralisation of sludge for treatment and disposal| as adopted by Thames Water Utilities Ltd.| is an environmental improvement upon the current practice. One of these options| that of complete centralisation and composting of sludge prior to disposal| exerts the least environmental impact with respect to Global warming potential. This suggests that the adoption of composting at Crawley is environmentally preferable to increasing the digestion facility at this works. (C) 1998 IAWQ. Published by Elsevier Science Ltd. All rights reserved. 4548,1998,4,4,ATLID: The technology development programme for ESA's satellite-borne atmospheric lidar,The idea of deploying a lidar system on an Earth-orbiting satellite stems from the need for continuously providing profiles of our atmosphereis structure with high resolution and global coverage. Interest in this information for climatology| meteorology and the atmospheric sciences in general is huge. Areas of application range from the determination of global warming and greenhouse effects| to monitoring the transport and accumulation of pollutants in the different atmospheric regions (such as the recent fires in Southeast Asia)| to the assessment of the largely unknown micro-physical properties and the structural dynamics of the atmosphere itself. 4544,1998,2,3,Atmospheric moisture residence times and cycling: Implications for rainfall rates and climate change,New estimates of the moistening of the atmosphere through evaporation at the surface and of the drying through precipitation are computed. Overall| the e-folding residence time of atmospheric moisture is just over 8 days. New estimates are also made of how much moisture that precipitates out comes from horizontal transport versus local evaporation| referred to as 'recycling'. The results depend greatly on the scale of the domain under consideration and global maps of the recycling for annual means are produced for 500 km scales for which global recycling is 9.6%| consisting of 8.9% over land and 9.9% over the oceans. Even for 1000 km scales| less than 20% of the annual precipitation typically comes from evaporation within the domain. While average overall atmospheric moisture depletion and restoration must balance| precipitation falls only a small fraction of the time. Thus precipitation rates are also examined. Over the United States| one hour intervals with 0.1 mm or more are used to show that the frequency of precipitation ranges from over 30% in the Northwest| to about 20% in the Southeast and less than 4% just east of the continental divide in winter| and from less than 2% in California to over 20% in the Southeast in summer. In midlatitudes precipitation typically falls about 10% of the time| and so rainfall rates| conditional on when rain is falling| are much larger than evaporation rates. The mismatches in the rates of rainfall versus evaporation imply that precipitating systems of all kinds feed mostly on the moisture already in the atmosphere. Over North America| much of the precipitation originates from moisture advected from the Gulf of Mexico and subtropical Atlantic or Pacific a day or so earlier. Increases in greenhouse gases in the atmosphere produce global warming through an increase in downwelling infrared radiation| and thus not only increase surface temperatures but also enhance the hydrological cycle| as much of the heating at the surface goes into evaporating surface moisture. Global temperature increases signify that the water-holding capacity of the atmosphere increases and| together with enhanced evaporation| this means that the actual atmospheric moisture should increase. It follows that naturally-occurring droughts are likely to be exacerbated by enhanced potential evapotranspiration. Further| globally there must be an increase in precipitation to balance the enhanced evaporation but the processes by which precipitation is altered locally are not well understood. Observations confirm that atmospheric moisture is increasing in many places| for example at a rate of about 5% per decade over the United States. Based on the above results| we argue that increased moisture content of the atmosphere therefore favors stronger rainfall or snowfall events| thus increasing risk of flooding| which is a pattern observed to be happening in many parts of the world. Moreover| because there is a disparity between the rates of increase of atmospheric moisture and precipitation| there are implied changes in the frequency of precipitation and/or efficiency of precipitation (related to how much moisture is left behind in a storm). However| an analysis of linear trends in the frequency of precipitation events for the United States corresponding to thresholds of 0.1 and 1 mm/h shows that the most notable statistically significant trends are for increases in the southern United States in winter and decreases in the Pacific Northwest from November through January| which may be related to changes in atmospheric circulation and storm tracks associated with El Nino-Southern Oscillation trends. It is suggested that as the physical constraints on precipitation apply only globally| more attention should be paid to rates in both observations and models as well as the frequency of occurrence. 4573,1998,4,4,Australian temperature| Australian rainfall and the Southern Oscillation| 1910-1992: coherent variability and recent changes,The best available surface temperature (T) and precipitation (P) records for Australia dating back to 1910 have been examined to look| for coherent interannual variability. P exhibits a tendency to be out of phase with daily maximum temperature| Tmax| and this results in P tending to be out of phase with both the daily average temperature| Tbar (estimated here as the average of Tmax and the daily minimum| Tmin)| and the DTR (diurnal temperature range| Tmax-Tmin). The association between P and Tmin is generally weak. The (expected) increase in P associated with a positive Southern Oscillation Index is (generally) accompanied by reduced average temperatures (Tbar) and a reduced DTR| both of which primarily arise from a reduction in Tmax. When variability in both P and Tmin associated with Tmax is removed| the residual signals (P* and Tmin*) show wide-spread statistically significant positive correlations| consistent with the hypothesis that clouds help to reduce night-tine cooling. These relationships are less clear at near-coastal sites| and absent at the island and exposed coastal sites considered. Results from three separate ten-year integrations of the Bureau of Meteorology Research Centre's atmospheric general circulation model were then examined. The tendency for (a) P to be out of phase with Tmax| Tbar and the DTR and (b) P* to be in phase with Tmin* over Australia on interannual time-scales was also generally evident over land elsewhere| except at high latitudes and over North Africa. An analysis of the model's surface heat budget over land showed that this arises from associated surface short wave radiation and latent heating anomalies. The latter is generally more important over low-latitude regions where deep convection occurs| with the hierarchy reversed elsewhere. Evaporative cooling anomalies appear to be dominated by soil moisture changes. Surface long wave radiation| sensible heating and subterranean heat exchange tend to reduce the temperature change which would otherwise occur. Recent changes in some of the relationships exhibited between observed P|T and the Southern Oscillation Index appear unusual in terms of the interdecadal variability evident in the records prior to 1972| and previous conclusions drawn on the basis of 'all-Australia' P and T indices were found to have broad applicability. Interrelationships between recent changes in the 20-year means of P| T and the SOI do not match the changes that might be expected on the basis of their interrelationship on interannual time-scales. Possible reasons for the changes suggested by the analysis (e.g.| global warming and naturally occurring interdecadal climate variability) are discussed. 2326,1998,2,4,Biodiversity of Collembola and their functional role in the ecosystem,More than 6500 species of Collembola are known from throughout the world and these an only a small part of the still undescribed species. There are many checklists and catalogues of Collembola for smaller territories and entire continents. Biogeographical analyses have been made for some genera and smaller territories. The most serious problems for a global biogeographical analysis is the lack of enough records from immense territories of all continents. Local biodiversity of Collembola can be very high| reaching over 100 species in small mountain ranges. Sampling methods do not impede documenting biodiversity on a global scale. Collembola have well differentiated ecomorphological life-forms and Feeding guilds which enable the functional role that Collembola play in ecosystems to be recognised in some degree. Collembola play an important role in plant litter decomposition processes and in forming soil microstructure. They are hosts of many parasitic Protozoa. Nematoda| Trematoda and pathogenic bacteria and in turn are attacked by different predators. They utilise as food Protozoa| Nematoda| Rotatoria| Enchytraeidae| invertebrate carrion| bacteria| fungi| algae| plant litter| live plant tissues| and some plant pathogens. Soil acidification| nitrogen supply| global climate change and intensive farming have greatly impacted collembolan diversity. 2368,1998,2,4,Biodiversity of marine plants in an era of climate change: Some predictions based on physiological performance,There are too few data to allow any confident statements on the effects of global climate change on the diversity of marine plant life. However| on the basis of information available in the literature| it is possible to make predictions about the physiological responses of plants under situations of anticipated increases in CO(2) concentrations| temperature and UV-B fluxes and point out how differences in the responses of major marine plant groups might lead to changes in performance and distribution of these organisms. For instance we may predict that macrophytes such as seagrasses will show enhanced photosynthetic rates and growth as atmospheric CO(2) levels continue to rise whilst many intertidal macroalgae are already at CO(2) saturation and may not show any enhanced performance as CO(2) increases. Decreasing ozone concentrations in the stratosphere will lead to enhanced UV-B fluxes and could consequently favour those species with UV tolerance or repair mechanisms. It has been suggested that interactions between temperature range and photoperiod can be responsible for excluding species from particular regions of the world's oceans. Other species might be affected in this way as temperatures at a given latitude change. Temperature will also influence the relationship between atmospheric and dissolved CO(2) and the proportions of the various components of dissolved inorganic carbon available for growth. Climate change may well have other effects on the efficiency with which marine plants use other resources such as N| Fe or Zn and these will also be discussed. 4676,1998,2,4,Bird migration: Genetic programs with high adaptability,Experiments during the past 20 years have shown that bird migration| especially partial migration| is an extremely adaptable life and survival strategy. With selected species - the Blackcap (Sylvia atricapilla) and Redstarts (genus Phoenicurus)- it has been shown that all the basic processes and features of migration| such as migratory drive| migratory disposition and activity| and orientation behaviour| are under direct genetic control. The considerable phenotypic and additive genetic variation in these traits provides a great potential for microevolution. Partial migration - the occurrence of migratoriness and sedentariness within the same population - appears to play a major role: it is a turntable| so to speak| for appropriate adaptations. Extremely widespread at higher latitudes and also common in the tropics| partial migration may be a fundamental pattern of avian behaviour. Its phenotypic dichotomy migrant-nonmigrant is caused by a genetic threshold mechanism| on the basis of which full migratoriness or sedentariness can be selected within a few generations. Since incidence and amount of migratory activity clearly represent a genetically integrated migration syndrome| downward selection of migratory activity in exclusively migratory populations resulting in shorter migration distances would also lead to partial migration. Birds are thus evidently capable of adapting to changing environmental conditions by shifting from almost full sedentariness to exclusive migratoriness and vice versa based on selection. Experimental and field evidence indicates that such a shift can be accomplished in less than 50 years| which makes partial migration a highly adaptive trait. 4602,1998,2,4,Boreal forest plants take up organic nitrogen,Plant growth in the boreal forest| the largest terrestrial biome| is generally limited by the availability of nitrogen. The presumed cause of this limitation is slow mineralization of soil organic nitrogen(1|2). Here we demonstrate| to our knowledge for the first time| the uptake of organic nitrogen in the field by the trees Pinus sylvestris and Picea abies| the dwarf shrub Vaccinium myrtillus and the grass Deschampsia flexuosa. These results show that these plants| irrespective of their different types of root-fungal associations (mycorrhiza)| bypass nitrogen mineralization. A trace of the amino acid glycine| labelled with the stable isotopes C-13 and N-15| was injected into the organic (mor) layer of an old successional boreal coniferous forest. Ratios of C-13:N-15 in the roots showed that at least 91| 64 and 42% of the nitrogen from the absorbed glycine was taken up in intact glycine by the dwarf shrub| the grass and the trees| respectively. Rates of glycine uptake were similar to those of N-15-ammonium. Our data indicate that organic nitrogen is important for these different plants| even when they are competing with each other and with non-symbiotic microorganisms. This has major implications for our understanding of the effects of nitrogen deposition| global warming and intensified forestry. 4515,1998,5,4,Bottom currents| sedimentation and ice-sheet retreat facies successions on the Mac Robertson shelf| East Antarctica,Measurements of water turbidity| currents| seafloor sediment samples and geophysical data document the sedimentary processes and the Late Quaternary sedimentary history of a continental shelf valley system on the East Antarctic continental margin. The valley is up to 1200 m in depth and strikes across the shelf; it is interpreted as having formed by glacial erosion processes; On the outer-shelf sill of the valley| northwestward (offshore) currents with speeds of up to 0.47 m/s referenced to 100 cm above the seabed were recorded over a 10-month period. Such currents are competent to initiate bedload transport of medium sand and formation of small (ripple-sized) bedforms which explains the occurrence of ripple cross-bedding observed in some X-radiographs of cores. A nepheloid layer with concentrations of up to 3.5 mg/l was noted at two stations and the available evidence suggests that density flows resulting from the sea-ice brine-rejection mechanism are competent to entrain shelf bottom sediments episodlically. Sediment cores taken from this environment document the succession of facies resulting from retreat of glacial ice from the shelf during the Holocene transgression. Under low sea-level| glacial conditions| the ice sheet is interpreted to have been grounded on the outer shelf| where it deposited a grounding line moraine. Rising sea level and global warming caused the ice shelf to retreat leaving a sub-ice shelf| glacial-marine mud. This is overlain by a laminated to massively bedded ice-rafted debris-rich facies| interpreted as being deposited at the glacial calving front. Above this is a siliceous mud and ooze facies having a basal age of about 10|000 years BP| characterising modern| open-marine conditions. Two types of iceberg keel marks on the outer part of the shelf valley are recognised from sidescan sonographs: one relict| arcuate type formed during the retreat of the ice shelf prior to 10|000 years BP and a second modern| elongate type that is presently being formed near the shelf break by iceberg grounding processes. This facies succession has been described from other Antarctic shelf environments and is probably representative of facies deposited during Holocene glacial retreat from the Antarctic shelf. (C) 1998 Elsevier Science B.V. All rights reserved. 2331,1998,4,4,CAPE variations in the current climate and in a climate change,Observed variations of convective available potential energy (CAPE) in the current climate provide one useful rest of the performance of cumulus parameterizations used in general circulation models (GCMs). It is found that frequency distributions of tropical Pacific CAFE| as well as the dependence of CAFE on surface wet-bulb potential temperature (Theta(w)) simulated by the Goddard Institute for Space Studies's GCM| agree well with that observed during the Australian Monsoon Experiment period| CAFE variability in the current climate greatly overestimates climatic changes in basinwide CAFE in the tropical Pacific in response to a 2 degrees C increase in sea surface temperature (SST) in the GCM because of the different physics involved. In the current climate| CAFE variations in space and time are dominated by regional changes in boundary layer temperature and moisture| which in turn are controlled by SST patterns and large-scale motions. Geographical thermodynamic structure variations in the middle and upper troposphere are smaller because of the canceling effects of adiabatic cooling and subsidence warming in the rising and sinking branches of the Walker and Hadley circulations. In a forced equilibrium global climate change| temperature change is fairly well constrained by the change in the moist adiabatic lapse rate and thus the upper troposphere warms to a greater extent than the surface. For this reason| climate change in CAFE is better predicted by assuming that relative humidity remains constant and that the temperature changes according to the moist adiabatic lapse rate change of a parcel with 80% relative humidity lifted from the surface. The moist adiabatic assumption is not symmetrically applicable to a warmer and colder climate: In a warmer regime moist convection determines the tropical temperature structure| but when the climate becomes colder the effect of moist convection diminishes and the large-scale dynamics and radiative processes become relatively important. Although a prediction based on the change in moist adiabat marches the GCM simulation of climate change averaged over the tropical Pacific basin| it does not match the simulation regionally because small changes in the general circulation change the local boundary layer relative humidity by 1%-2%. Thus| the prediction of regional climate change in CAFE is also dependent on subtle changes in the dynamics. 4671,1998,3,4,Carbon cycle for rapeseed oil biodiesel fuels,The greenhouse effect| thought to be responsible for global warming| is caused by gases accumulating in the earth's atmosphere. Carbon dioxide| which makes up half of the gas accumulation problem| is produced during respiration and combustion processes. This paper provides an outline of the carbon cycle for rapeseed oil-derived fuels. Plant processes| fuel chemistry and combustion are examined with respect to carbon. A diagram is presented to interpret the information presented graphically. A comparison of carbon dioxide emissions from the combustion of rapeseed oil biodiesel and petroleum diesel is made. Complete combustion converts hydrocarbon fuels so carbon dioxide and water. The carbon cycle consists of the fixation of carbon and the release of oxygen by plants through the process of photosynthesis| then the recombining of oxygen and carbon to form CO2 through the processes of combustion and respiration. The carbon dioxide released by petroleum diesel was fixed from the atmosphere during the formative years of the earth. Carbon dioxide released by biodiesel is fixed by the plant in a recent year and is recycled. Many scientists believe that global warming is occurring because of the rapid release of CO2 in processes such as the combustion of petroleum diesel. Using biodiesel could reduce the accumulation of CO2 in the atmosphere. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. 2323,1998,2,4,Carbon dioxide and methane fluxes by a forest soil under laboratory-controlled moisture and temperature conditions,Carbon dioxide and methane are important greenhouse gases whose exchange rates between soils and the atmosphere are controlled strongly by soil temperature and moisture. We made a laboratory investigation to quantify the relative importance of soil moisture and temperature on fluxes of CO(2) and CH(4) between forest soils and the atmosphere. Forest floor and mineral soil material were collected from a mixed hardwood forest at the Harvard Forest. Long-Term Ecological Research Site (MA) and were incubated in the laboratory under a range of moisture (air-dry to nearly saturated) and temperature conditions (5-25 degrees C). Carbon dioxide emissions increased exponentially with increasing temperature in forest floor material| with emissions reduced at the lowest and highest soil moisture contents. The forest floor Q(10) of 2.03 (from 15-25 degrees C) suggests that CO(2) emissions were controlled primarily by soil biological activity. Forest floor CO(2) emissions were predicted with a multiple polynomial regression model (r(2) = 0.88) of temperature and moisture| but the fit predicting mineral soil respiration was weaker (r(2) = 0.59). Methane uptake was controlled strongly by soil moisture| with reduced fluxes under conditions of very low or very high soil moisture contents. A multiple polynomial model accurately described CH(4) uptake by mineral soil material (r(2) = 0.81)| but only weakly (r(2) = 0.45) predicted uptake by forest floor material. The mineral soil Q(10) of 1.11 for CH(4) uptake indicates that methane uptake is controlled primarily by physical processes. Our work suggests that inclusion of both moisture and temperature can improve predictions of soil CO(2) and CH(4) exchanges between soils and the atmosphere. Additionally| global change models need to consider interactions of temperature and moisture in evaluating effects of global climate change on trace gas fluxes. (C) 1998 Elsevier Science Ltd. All rights reserved. 4501,1998,2,4,Carbon dioxide fluxes in moist and dry arctic tundra during season: Responses to increases in summer temperature and winter snow accumulation,Climate-induced environmental changes are likely to have pronounced impacts on CO2 flux patterns in arctic ecosystems. We initiated a long-term experiment in 1994 in moist tussock and dry heath tundra in arctic Alaska in which we increased summer air temperature (ca. 2 degrees C) and increased winter snow accumulation (shortening the growing season approximately 4 wk). During the 1996 snow-free season| we measured ecosystem CO2 flux weekly in order to quantify net carbon gain or loss from these systems. Over the duration of the snow-free season| both dry heath and moist tussock tundra exhibited a net loss of carbon to the atmosphere| ranging from 12 to 81 g C m(-2) depending upon experimental treatment. Elevated summer temperatures accelerated net CO2 loss rates over ambient temperatures in both deep and ambient snow treatments| and increased the total amount of carbon emitted during the snow-free season by 26 to 38% in ambient snow plots and by 112 to 326% in deep snow plots. Increased snow accumulation had less impact on CO2 flux than did warming| and snow effects on total carbon loss were not consistent between the two temperature regimes. Ecosystem respiration exceeded assimilation on most sampling dates throughout the season. These data| coupled with winter carbon losses recently demonstrated in the same ecosystems| indicate that the moist and dry arctic ecosystems we examined are currently net sources of atmospheric carbon on an annual basis| and that anticipated global warming may increase carbon losses from these systems. 4538,1998,4,3,Carbon in the vegetation and soils of Northern Ireland,The amount of carbon stored in vegetation and soils (including peat) in Northern Ireland has been estimated and the distributions mapped on a 1 km x 1 km grid as part of a national inventory. This was funded by Government to help meet some of its commitments under the UN Framework Convention on Climate Change. Knowing the sizes of the carbon stores (reservoirs) and the factors influencing them will help in developing policies to protect and enhance them as a contribution to the amelioration of global warming. To calculate these carbon stores| the area and carbon density of each vegetation and soil type were required. Similar data sources and methods were used to those in complementary inventories in Great Britain| but modifications were required ill Northern Ireland| including the use of CORINE land cover (classification and maps) and the development of a soil carbon database. The total amount of carbon stored is estimated to be 4.4Mt in vegetation (5.1Mt| allowing for forests underestimated by CORINE) and 386Mt in soils. Forests account for 55% of the carbon in vegetation| and peat for 42% of: that in soils-a product of their relatively high carbon densities. 4525,1998,4,4,Carbon isotopic analysis of atmospheric methane in urban and suburban areas: Fossil and non-fossil methane from local sources,The carbon isotopic composition (C-12| C-13 and C-14) of atmospheric CH4 was studied to estimate CH4 sources in local areas. In urban areas of Nagoya| Japan (35 degrees 10'N| 136 degrees 55'E)| where there is much anthropogenic influence| evidence of methane release into the atmosphere has been reported. Variations in the carbon isotopic composition were analyzed with diurnal fluctuation of atmospheric CH4 concentration| since the diurnal increase in the CH4 concentration is attributed mainly to release from local sources. In November and December 1993| the contribution of fossil CH| to local CH| released from the urban area was calculated to be 102 +/- 8%| and delta(13)C was -40.8 +/- 3.0 parts per thousand. Leakage of supplied natural gas and exhaust gas from automobiles would he important CH| sour;es in the urban area in late autumn to winter. In suburban areas ill Japan there are many rice paddy fields| and these are one kind of major anthropogenic source of atmospheric CH4. In a suburban area of Nagoya fossil| CH4 contributed to less than 10% of local release in July and august 1994. The calculated value of delta(13)C for non-fossil CH4 was approximately - 65 parts per thousand| which is within the range of reported values of delta(13)C for CH4 derived from bacterial CH4 sources such as irrigated rice paddies. (C) 1998 Elsevier Science Ltd. All rights reserved. 4505,1998,2,4,Changes in a North Carolina reef fish community after 15 years of intense fishing - Global warming implications,A North Carolina reef fish community was resurveyed with scuba gear to determine if changes occurred in community structure after 15 years of intense fishing. Generally| fishes important in the recreational and commercial fisheries were smaller. and large changes occurred in relative abundance and species composition. Indicative of a warming trend| total species corn position of fishes had become more tropical| and a tropical sponge previously unrecorded at this latitude off the North Carolina coast became common. Two new (to the area) families and 29 new species of tropical fishes were recorded. Observations of 28 species of tropical reef fishes increased significantly. No new temperate species were observed| and the most abundant temperate species decreased by a factor of 22. Mean monthly bottom water temperatures in winter were 1-6 degrees C warmer during the recent study. An increase in fish-cleaning symbiosis was especially noticeable. 2351,1998,3,4,Changes in soil carbon following afforestation in Hawaii,Afforestation in the tropics may sequester soil C and has been proposed as a management tool to aid in controlling rising levels of atmospheric CO2. We measured changes in soil C following afforestation of sugarcane fields with fast-growing Eucalyptus saligna (Sm.) plantations in Hawaii. Using stable C isotopes| we estimated the contributions to changes in total soil C that were due to the loss of C from the prior cane cultivation| and to the gain of C from the new Eucalyptus plantations. Total soil C 10-13 yr after afforestation was 114 and 113 Mg/ha| respectively| in the Eucalyptus and cane plantation. Eucalyptus increased total soil C in the 0-10 cm layer by 11.5 Mg/ha| but that was offset by a loss of 10.1 Mg/ha of cane-derived C from the 10-55 cm layer. The net effect on soil C of afforestation of cultivated lands depends not only on new C gained| but also on C lost from the previous management. 4608,1998,4,2,Changing concentration| lifetime and climate forcing of atmospheric methane,Previous studies on ice core analyses and recent in situ measurements have shown that CH(4) has increased from about 0.75 to 1.73 mu mol/mol during the past 150 years. Here| we review sources and sink estimates and we present global 3D model calculations| showing that the main features of the global CH(4) distribution are well represented. The model has been used to derive the total CH(4) emission source| being about 600 Tg yr(-1). Based on published results of isotope measurements the total contribution of fossil fuel related CHI emissions has been estimated to be about 110 Tg yr(-1). However| the individual coal| natural gas and oil associated CH(4) emissions can not be accurately quantified. In particular natural gas and oil associated emissions remain speculative. Since the total anthropogenic CH(4) source is about 410 Tg yr(-1) (similar to 70% of the total source) and the mean recent atmospheric CH(4) increase is similar to 20 Tg yr(-1) an anthropogenic source reduction of 5% could stabilize the atmospheric CH(4) level. We have calculated the indirect chemical effects of increasing CH(4) on climate forcing on the basis of global 3D chemistry-transport and radiative transfer calculations. These indicate an enhancement of the direct radiative effect by about 30%| in agreement with previous work The contribution of CH(4) (direct and indirect effects) to climate forcing during the past 150 years is 0.57 W m(-2) (direct 0.44 W m(-2)| indirect 0.13 W m(-2)). This is about 35% of the climate forcing by CO(2) (1.6 W m(-2)) and about 22% of the forcing by all long-lived greenhouse gases (2.6 W m(-2)). Scenario calculations (IPCC-IS92a) indicate that the CH(4) lifetime in the atmosphere increased by about 25-30% during the past 150 years to a current value of 7.9 years. Future lifetime changes are expected to be much smaller| about 6%| mostly due to the expected increase of tropospheric O(3) (-->OH) in the tropics. The global mean concentration of CH(4) may increase to about 2.55 mu mol/mol| its lifetime is expected to increase to 8.4 years in the year 2050. Further| we have calculated a CH(4) global warming potential (GWP) of 21 (kgCH(4)/kgCO(2)) over a time horizon of 100 years| in agreement with IPCC (1996). Scenario calculations indicate that the importance of the climate forcing by CH(4) (including indirect effects) relative to that of CO(2) will decrease in future; currently this is about 35%| while this is expected to decrease to about 15% in the year 2050. 4587,1998,2,3,Changing waves and storms in the northeast Atlantic?,The European project WASA (Waves and Storms in the North Atlantic) has been set up to verify or disprove hypotheses of a worsening storm and wave climate in the northeast Atlantic and its adjacent seas in the present century. Its main conclusion is that the storm and wave climate in most of the northeast Atlantic and in the North Sea has undergone significant variations on timescales of decades; it has indeed roughened in recent decades| but the present intensity of the storm and wave climate seems to be comparable with that at the beginning of this century. Part of this variability is found to be related to the North Atlantic oscillation. An analysis of a high-resolution climate change experiment| mimicking global warming due to increased greenhouse gas concentrations| results in a weak increase of storm activity and (extreme) wave heights in the Bay of Biscay and in the North Sea| while storm action and waves slightly decrease along the Norwegian coast and in most of the remaining North Atlantic area. A weak increase in storm surges in the southern and eastern part of the North Sea is expected. These projected anthropogenic changes at the time of CO2 doubling fall well within the limits of variability observed in the past. A major methodical obstacle for the assessment of changes in the intensity of storm and wave events are inhomogeneities in the observational record| both in terms of local observations and of analyzed products (such as weather maps)| which usually produce an artificial increase of extreme winds. This occurs because older analyses were based on fewer observations and with more limited conceptual and numerical models of the dynamical processes than more recent analyses. Therefore the assessment of changes in storminess is based on local observations of air pressure and high-frequency variance at tide gauges. Data of this sort is available for 100 yr and sometimes more. The assessment of changes in the wave climate is achieved using a two-step procedure; first a state-of-the-art wave model is integrated with 40 yr of wind analysis; the results are assumed to be reasonably homogeneous in the area south of 70 degrees N and east of 20 degrees W; then a regression is built that relates monthly mean air pressure distributions to intramonthly percentiles of wave heights at selected locations with the help of the 40-yr simulated data; finally| observed monthly mean air pressure fields from the beginning of this century are fed into the regression model to derive best guesses of wave statistics throughout the century. 2327,1998,2,4,Chaos in the Pacific's coral reef bleaching cycle,There is no simple explanation for the unusual increase in coral reef bleaching events that have been occurring on a global scale over the last 2 decades. Recent studies focusing on this problem reveal that mass bleaching events have a strong periodic component| arising every similar to 3-4 yr in step with the El Nino climatic phenomenon. To explore this possibility further| we examine a simple oceanographic-ecological model designed to simulate the warm and cool phases of the Pacific Ocean cycle and gauge its effect on local coral reefs. This allows us to identify causes for localized "hot spots" in the ocean| whose high sea surface temperatures have disastrous consequences for corals. The underlying wave dynamics of the model lead to chaotic oscillations (every similar to 3-4 yr)| which help explain the coexistence of both order and irregularity in the dynamics of mass bleaching. The model makes use of a temperature threshold mechanism-a bleaching event is triggered whenever temperature anomalies exceed a critical level. In a variable environment| the threshold mechanism is sensitive to background fluctuations| and their effects are studied by making use of a "stochastic resonance" formulation. Global climate change and other trends in external background environmental conditions are all shown to strongly influence the distribution of mass coral bleaching events. 4518,1998,2,4,Characteristics of energy and water budgets over wet sedge and tussock tundra ecosystems at North Slope in Alaska,Energy budgets were measured at Arctic tundra ecosystems in Alaska| USA. Measurements were carried out over coastal tundra at Prudhoe Bay in 1994| and at wet sedge| moist and dry tussock tundra around Happy Valley in 1995. Sensible heat flux| H| and latent heat flux| lE| were determined by an eddy correlation technique. Over the Arctic coastal tundra| the energy partition changed remarkably as a result of air mass conditions. Under cold and humid wild (onshore) from the Arctic Ocean| the temperature gradient over the tundra ecosystem increased| which resulted in a high level of H. Under warm and dry air mass on clear days from the inland tundra (offshore)| air and soil temperatures and the water vapour deficit increased| which resulted in an increase in lE. The same effect or air mass condition on energy partition was observed at the tundra ecosystem in Happy Valley located 135 km inland from the Arctic coast. The energy budget at wet sedge tundra was characterized as the heat storage within the water layer on a daily basis| which was partitioned mainly to lE in daytime and lE and H at night. Latent heat flux| lE| was largest at wet sedge tundra and lowest at dry tussock tundra. The Bowen ratio decreased with air temperature over wet sedge and dry tussock tundra ecosystems. The aerodynamic resistance r(a)| and canopy resistance| r(c)| over the wet sedge tundra at Happy Valley had different levels over four major wind directions. These levels decreased with increase in wind speed. r(a) was slightly higher than over other vegetation| which seemed to be owing to a relatively lower wind speed| while the canopy resistance r(c) was lower than over other vegetation. Global warming will affect the energy partition of the Arctic tundra ecosystem| and the warming and drying climate will increase the lE of tundra| especially in flooded areas. Expanding dry tundra increases H rather than lE| which enhances the warming of the tundra ecosystem. (C) 1998 John Wiley & Sons| Ltd. 2367,1998,5,4,Chemical weathering in a tropical watershed| Luquillo mountains| Puerto Rico: I. Long-term versus short-term weathering fluxes,The pristine Rio Icacos watershed in the Luquillo Mountains in eastern Puerto Rico has the fastest documented weathering rate of silicate rocks on the Earth's surface. A regolith propagation rate of 58 m Ma(-1)| calculated from iso-volumetric saprolite formation from quartz diorite| is comparable to the estimated denudation rate (25-50 Ma(-1)) but is an order of magnitude faster than the global average weathering rate (6 Ma(-1)). Weathering occurs in two distinct environments; plagioclase and hornblende react at the saprock interface and biotite and quartz weather in the overlying thick saprolitic regolith. These environments produce distinctly different water chemistries| with K| Mg| and Si increasing linearly with depth in saprolite porewaters and with stream waters dominated by Ca| Na| and Si. Such differences are atypical of less intense weathering in temperate watersheds. Porewater chemistry in the shallow regolith is controlled by closed-system recycling of inorganic nutrients such as K. Long-term elemental fluxes through the regolith (e.g.| Si = 1.7 x 10(-8)moles m(-2) s(-1)) are calculated from mass losses based on changes in porosity and chemistry between the regolith and bedrock and from the age of the regolith surface (200 Ma). Mass losses attributed to solute fluxes are determined using a step-wise infiltration model which calculates mineral inputs to the shallow and deep saprolite porewaters and to stream water. Pressure heads decrease with depth in the shallow regolith (-2.03 m H(2)O m(-1))| indicating that both increasing capillary tension and graviometric potential control porewater;infiltration. Interpolation of experimental hydraulic conductivities produces an infiltration rate of 1 m yr(-1) at average field moisture saturation which is comparable with LiBr tracer tests and with base discharge from the watershed. Short term weathering fluxes calculated from solute chemistries and infiltration rates (e.g.| Si = 1.4 x 10(-8) moles m(-2) s(-1)) are compared to watershed flux rates (e.g.| Si = 2.7 x 10(-8) moles m(-2) s(-1)). Consistency between three independently determined sets of weathering fluxes imply that possible changes in precipitation| temperature| and vegetation over the last several hundred thousand years have not significantly impacted weathering rates in the Luquillo Mountains of Puerto Rico. This has important ramifications for tropical environments and global climate change. Copyright (C) 1998 Elsevier Science Ltd. 4613,1998,2,4,Chronic exposure of rainbow trout (Oncorhynchus mykiss) to simulated climate warming and sublethal ammonia: a year-long study of their appetite| growth| and metabolism,This study was conducted to assess| over the thermal cycle of an entire year| the effects (on appetite| growth| and metabolism) of a chronic small temperature increase (+2 degrees C) and sublethal ammonia (70 mu mol.L-1) on rainbow trout (Oncorhynchus mykiss). Juvenile rainbow trout (approximate to 11 g initially) were exposed for 14 months to four treatments: the natural water temperature cycle of the inshore region of Lake Ontario| this cycle +2 degrees C to simulate a global warming scenario| and these temperature cycles in the presence of an additional 70 mu mol total ammonia.L-1 (NH3 range: 0.005-0.013 mg.L-1). The additional +2 degrees C substantially increased appetite over winter| significantly elevating specific growth rates. These gains were lost| however| over summer due to suppression of appetite and growth at high temperature. Ammonia alone tended to elevate growth| but the combination of +2 degrees C and ammonia resulted in a general decrease in the activity of enzymes involved in nitrogen metabolism (alanine aminotransferase| aspartate aminotransferase| glutamate dehydrogenase| and glutamine synthetase). These results document the dramatic influence of a +2 degrees C warming scenario on the growth and feeding metabolism of juvenile rainbow trout. Moreover| the data indicate that a chronic small temperature increase| together with low-level ammonia pollution| substantially alters protein dynamics| and hence growth| in juvenile freshwater fishes; juvenile rainbow trout without thermal refuge will experience an increase in t a warmer| more polluted environment. 4586,1998,4,4,Cirrus cloud simulation using explicit microphysics and radiation. Part II: Microphysics| vapor and ice mass budgets| and optical and radiative properties,The 2D/3D cloud model complex with explicit microphysics and radiation described in Part I is used to simulate the development of a midlatitude cirrus cloud? including interaction with radiation. To account for the effects of the interaction of various scales of motion on cloud development| a synoptic-scale vertical velocity field is superimposed on the mesoscale velocity field generated by the model| mimicking the effects of an upper-level shortwave trough. The main results under the conditions simulated here are the following. Cirrus cloud growth is much slower than assumed previously| because the process of vapor deposition to ice crystals is far from instantaneous: the crystal phase relaxation time (i.e.| the characteristic time of vapor absorption by crystals) takes 0.5-2.0 h. Even after 1 h of cloud development| supersaturation with respect to ice can remain 5%-10%| while the condensed ice is only 40%-60% of the amount that would be realized assuming that all excess vapor is transformed into ice in typical model time steps. Although experimental and theoretical studies have produced widely divergent longwave mass absorption coefficients alpha(m)(abs)| ranging from 100 to 3500 cm(2) g(-1)| model results show that a single "representative" value of alpha(m)(abs) is inappropriate. Vertical profiles typically exhibit values of similar to 800-1000 cm(2) g(-1) in the upper cloud region containing the smallest particles| in contrast to similar to 100-300 cm(2) g(-1) for the larger crystals in the main cloud. The optical scattering coefficients behave similarly| with typical values of similar to 2000-2500 cm(2) g(-1) in the upper cloud regions and similar to 300-500 cm(2) g(-1) in the lower cloud regions. A strong horizontal variability is also a characteristic feature of these coefficients. Many GCM and climate models use seemingly overestimated alpha(m)(abs) values (e.g.| 1000 cm(2) g(-1)). Sensitivity tests show that the use of such values increases cooling in the upper cloud and heating in the lower cloud| which can lead to an unwarranted increase in upper-tropospheric static instability. The postulated effects of the positive feedbacks between clouds and greenhouse gas-induced global warming would likely be different in magnitude (or in sign) if the more realistic approach of using cloud microstructure-dependent absorption and scattering coefficients could be adopted. Consideration of microphysics also shows that the decrease in the shortwave radiative balance (albedo effect) in the simulated midlatitude cirrus cloud exceeds the net gain in the longwave balance (greenhouse effect) near midday| due to the abundance of relatively small crystals in the upper cloud region where cloud regeneration is taking place. 4577,1998,2,3,Climate change and its impacts on glaciers and permafrost in the Alps,Climate change in the European Alps during the 20th century has been characterized by increases in minimum temperatures of about 2 degrees C| a more modest increase in maximum temperatures| little trend in precipitation data| and a general decrease of sunshine duration through to the mid-1980s. Temperature increase has been most intense in the 1940s| followed by the 1980s. The warming experienced since the early 1980s| while synchronous with the global warming| is of far greater amplitude and reaches close to 1 degrees C for this ensemble average and up to 2 degrees C for individual sites. Such changes caused pronounced effects in the glacial and periglacial belts. Since the middle of the past century-the end of the Little Ice Age-the glacierization of the European Alps has lost about 30 to 40% in surface area and around half its original volume. The estimated total glacier volume in the European Alps was some 130 km(3) for the mid-1970s| but strongly negative mass balances have caused an additional loss of about 10 to 20% of this remaining ice volume since 1980. Periglacial permafrost in the Alps today occupies an area comparable to the glacierized area and must have been affected as well| but its secular evolution is much less well known. Simulations of high-resolution climatologies for double-CO(2) situations using regional climate models (RCM) with a 20-km horizontal grid give generally higher winter temperatures| a more marked increase in summer temperatures| indications that temperature increases more at higher elevations than at lower altitudes| and higher/ more intense precipitation in winter| but much dryer conditions in summer. Under such conditions| the Alps would lose major parts of their glacier cover within decades| warming of cold firn areas at high altitudes could become pronounced and lower limits of permafrost occurrence in the Alps could rise by several hundred meters. Pronounced disequilibria could result| in the water cycle| in mass wasting processes| and in sediment flux as well as in growth conditions of vegetation. For those directly involved with such changes| the main challenge would be to adapt to high and accelerating rates of environment evolution. Empirical knowledge would have to be replaced increasingly by improved process understanding| especially concerning runoff formation and slope stability. In view of the uncertainties involved with future projections| highest priority should be given to appropriate monitoring programs. 4649,1998,4,2,Climate change| the enhanced greenhouse effect and the influence of the sun: A statistical analysis,Changes in solar activity are regularly forwarded as an hypothesis to explain the observed global warming over the last century. The support of such claims is largely statistical| as knowledge of the physical relationships is limited. The statistical evidence is revisited. Changing solar activity is a statistically plausible hypothesis for the observed warming| if short-term natural variability is the only alternative explanation. Compared to the enhanced greenhouse effect| the solar hypothesis looses a substantial part of its plausibility. Reversely| the size and significance of the estimated impact of the enhanced greenhouse effect on the global mean temperature is hardly affected by solar activity. 2340,1998,2,4,Climate change| tick-borne encephalitis and vaccination needs in Sweden - a prediction model,A future| global| climate change may indirectly lead to changes in the transmission and incidence of several vector-borne diseases. This paper presents an example of a modeling tool for projections of possible changes in the incidence of tick-borne encephalitis (TBE)| and the subsequent changes in vaccination needs| during the next half-century in Sweden. The model is based on the Hadley Center's regional temperature predictions for the year 2050| taking into account the IPCC IS92 'non-intervention scenario'. The model has been constructed into STELLA| a graphical dynamic-simulation| soft-ware program. The model project an increase in TEE incidence in Stockholm County| a high-endemic region in Sweden| during the next 50 years. According to this simplified model| the annual vaccination rate need to increase by 3-4-fold during the next half century in order to prevent the projected increases in TEE incidence in the region from a climatic change. (C) 1998 Elsevier Science B.V. All rights reserved. 2318,1998,5,4,Climatic and tectonic implications of the late Miocene Jakokkota flora| Bolivian Altiplano,When compared to a database of modern foliar physiognomy and climate| the physiognomy of a new collection of dicotyledonous leaves from the 10.66 +/- 0.06 Ma Jakokkota flora| Bolivian Altiplano| implies a mean annual temperature (MAT) of 18.6-21.0 +/- 2.5 degrees C. Similarly| a literature-derived sample of the early-middle Miocene Potosi flora| Cordillera Oriental| implies a MAT of 21.5-21.7 +/- 2.1 degrees C. We estimate that both floras experienced a growing season precipitation of 50 +/- 40 cm. The paleoclimate thus appears considerably warmer than the current highland climate| with MATs of 8-9 degrees C; the paleoprecipitation is indistinguishable from modern levels. A comparison of the Miocene MATs with the modern MATs| with the effects of latitudinal continental drift and global climate change subtracted| suggests that the Jakokkota flora grew at an elevation of 590-1610 +/- 1000 m| and the Potosi flora grew at an elevation of 0-1320 +/- 1000 m. Both paleoelevation estimates are significantly lower than the present elevations of 3940 and 4300 m| respectively| requiring a substantial component of Andean uplift since 10.7 Ma. This uplift history is consistent with two-stage tectonic models of Andean orogeny. (C) 1998 Elsevier Science Ltd. All rights reserved. 2333,1998,2,4,Climatic warming and its effect on bud burst and risk of frost damage to white spruce in Canada,Temperature data from ten weather stations across Canada were used to model the effects of climate warming on the timing of bud burst and the risk of frost damage to white spruce (Picea glauca (Moench) Voss). There was evidence of increasingly earlier dates of bud break over the course of this century at half of the stations examined (Amos and Brome| Quebec; Cochrane| Ontario; Fort Vermilion| Alberta; and Woodstock| New Brunswick)| with the period 1981 to 1988 having the earliest predicted dates of bud burst (earliest degree day accumulation). Risk of frost damage at most stations in the 1980s was usually greater than in earlier periods. Weather data modelled for climate warming of 5 degrees C predicts that bud burst will occur two to four weeks sooner than was the case during 1961 to 1980 at all stations| but that this will generally be accompanied by decreased risk of frost after bud burst. However| while the expected trend is one of reduced frost risk in the future| as the climate gradually warms frost risk is expected to fluctuate upward or downward depending on interactions between provenance and local climate. 2339,1998,4,4,Clouds and the Earth's Radiant Energy System (CERES): Algorithm overview,The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS)| CERES objectives include the following. 1) For climate change analysis| provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA)| analyzed using the same techniques as the existing ERBE data. 2) Double the accuracy of estimates of radiative fluxes at TOA and the earth's surface; 3) Provide the first long-term global estimates of the radiative fluxes within the earth's atmosphere. 4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA| In order to accomplish these goals| CERES uses data from a combination of spaceborne instruments: CERES scanners| which are an improved version of the ERBE broadband radiometers| and collocated cloud spectral imager data on the same spacecraft. The CERES cloud and radiative flux data products should prove extremely useful in advancing the understanding of cloud-radiation interactions| particularly cloud feedback effects on the earth's radiation balance| For this reason| the CERES data should be fundamental to our ability to understand| detect| and predict global climate change| CERES results should also be very useful for studying regional climate changes associated with deforestation| desertification anthropogenic aerosols| and El Nino/Southern Oscillation events. This overview summarizes the Release 2 version of the planned CERES data products and data analysis algorithms. These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the earth's climate system. This release will produce a data processing system designed to analyze the first CERES data| planned for launch on Tropical Rainfall Measuring Mission (TRMM) in November 1997| followed by the EOS morning (EOS-AM1) platform in 1998. 4597,1998,3,4,CO2-heat pump water heater: characteristics| system design and experimental results,CO2 is one of the few non-toxic and non-flammable working fluids that do not contribute to ozone depletion or global warming| if leaked to the atmosphere. Tap water heating is one promising application for a trans-critical CO2 process. The temperature glide at heat rejection contributes to a very good temperature adaptation when heating tap water| which inherits a large temperature glide. This| together with efficient compression and good heat transfer characteristics of CO2| makes it possible to design very efficient systems. A heating-COP of 4.3 is achieved for the prototype when heating tap water from 9 degrees C to 60 degrees C| at an evaporation temperature of 0 degrees C| The results lead to a seasonal performance factor of about 4 for an Oslo climate| using ambient air as heat source. Thus| the primary energy consumption can be reduced with more than 75% compared with electrical or gas fired systems. Another significant advantage of this system| compared with conventional heat pump water heaters| is that hot water with temperatures up to 90 degrees C can be produced without operational difficulties. (C) 1998 Elsevier Science Ltd and IIR. All rights reserved. 4497,1998,3,4,Cocurrent biological nitrification and denitrification in wastewater treatment,Repetitive conditioning of recycle activated sludge IRAS) under strict anaerobic conditions gradually changes the products of ammonia oxidation from nitrite and nitrate to nitrous oxide (N2O) and nitrogen (N-2) Nitrite inhibits oxygen respiration of anaerobically conditioned sludge; biochemical oxygen demand (BOD) is then oxidized by nitrite| which is reduced to N2O and N-2. When anerobic RAS conditioning is initially imposed on a nitrifying system| Nitrobacter species continue to oxidize nitrite to nitrate and thus reduce the nitrite available to oxidize BOD. However| Nitrobacter in the mixed liquor gradually tend to wash out because the sole source of Nitrobacter energy| the oxidation of nitrite to nitrate| is diminished to the extent that nitrite is reduced. Incorporation of an RAS conditioning zone to the activated-sludge process results in evolution of a nonfilamentous biomass| which affects both cocurrent biological nitrification and denitrification (CBND) and biological phosphorus removal (BPR). The initial feed zone may be either aerobic or anaerobic. A final anoxic denitrification zone is desirable for removal of residual nitrite plus nitrate (NOx) from aeration effluent. Nitrous oxide| the main reaction product of CBND| promotes both global warming and destruction of the stratospheric ozone layer. 2347,1998,4,4,Combustion in natural fires and global emissions budgets,Fires in tropical savannas are a principal source of emissions to the atmosphere| but there are few studies of retention in ash and residual plant mass following natural fires. Estimates of carbon and nitrogen emissions to the atmosphere from biomass burning have relied largely on indirect measures from laboratory incineration. Emissions from incinerated samples are then extrapolated to areally extensive field estimates of flammable plant biomass. In addition| both direct sampling of smoke plumes and comparison to ambient atmospheric samples| with combustion efficiency estimated by ratios of trace gases to carbon dioxide in plumes| are employed. To the extent that combustion in natural fires departs from laboratory burning or that assumed average standing crops are inaccurate| indirect estimates based on laboratory emissions will be in error. Similarly| the relation of emission ratios to natural fire intensity is poorly understood and will influence the accuracy of estimates based on plume sampling. Recently| data from the Southern African Fire-Atmosphere Research Initiative (SAFARI) has indicated that indirect methods can overestimate the proportion of biomass combusted in natural fires. However| how combustion is related to fire temperature is quantitatively unknown. Studies of combustion efficiency in natural fires| as the proportion of initial biomass actually volatilized| are rare| and we know of no estimates of mass and N retention in residual ash and partially combusted biomass that are related to fire temperature. We burned plots instrumented with thermocouples to measure fire temperature and analyzed biomass from adjacent clipped plots| residual post-fire plant residue| and ash to determine the proportion of biomass actually burned and N volatilized. Data from experimental savanna grassland fires under natural conditions in Serengeti National Park indicate that (1) the proportions of mass and N volatilized are substantially less than 100%| (2) most fuel loads are within a range where combustion and volatilization are highly dependent on mass burned and resultant fire intensity| (3) proportionally more N than mass is volatilized| particularly as fire intensity increases| but (4) much less mass and N are volatilized in natural fires than laboratory estimates suggest. Therefore| (5) obtaining accurate estimates of emissions from natural fires will be substantially more difficult than is reflected in current methodology. 4498,1998,4,4,Comment on "Does the correlation between solar cycle lengths and Northern Hemisphere land temperatures rule out any significant global warming from greenhouse gases?" by Peter Laut and Jesper Gundermann,Currently there are two different views about the cause of the recently observed global warming. These opinions are the widely accepted concept of the influence of greenhouse gases and the notion of the solar impact on the terrestrial climate. Some difficulties arising from a statistical treatment of solar-terrestrial time series are discussed. It is stated that neither of the contrary positions relating to the global warming problem are in a position to claim that they possess the only truth. (C) 1999 Elsevier Science Ltd. All rights reserved. 4639,1998,2,4,Comparing heat stress effects on male-fertile and male-sterile tomatoes,To separate the effects of heat stress on male and female reproductive tissues| male-sterile (MSs) and male-fertile tomatoes (MFs) were placed in growth chambers at 12 h day/12 h night temperatures of 28/22| 30/24 or 32/26 degrees C from newer appearance to seed maturation (daily mean temperatures of 25| 27 or 29 degrees C). pollen from MFs was applied individually to MS flowers. As MFs were self-pollinated| heat stress was experienced by both male and female tissues. At growth temperatures of 29 degrees C fruit number| fruit weight per plant| and seed number per fruit were only 10%| 6.4% and 16.4%| respectively| compared with those at 25 degrees C| Heat stress also adversely affected fruitset in MSs| especially when experienced by donor pollen. No fruit at all developed on MSs receiving pollen produced at 29 degrees C| even when ovule development| pollen germination and subsequent embryo development all took place at 25 degrees C| Effects on fruitset in MSs were reduced if donor pollen had not experienced heat stress. MSs grown at 29 degrees C but receiving pollen developing at 25 degrees C produced 73% as much fruit (both on number and weight basis)| had 40% as high fruitset and produced 87% of the seed per fruit as MSs grown at 25 degrees C| This use of male-sterile and male-fertile lines of tomato provides new evidence that impairment of pollen and anther development by elevated temperature will be an important contributing factor to decreased fruit set in tomato| and possibly other crops| with global warming. 2358,1998,2,4,Dengue fever epidemic potential as projected by general circulation models of global climate change,Climate factors influence the transmission of dengue fever| the world's most widespread vector-borne virus. We examined the potential added risk posed by global climate change on dengue transmission using computer-based simulation analysis to link temperature output from three climate general circulation models (GCMs) to a dengue vectorial capacity equation. Our outcome measure| epidemic potential| is the reciprocal of the critical mosquito density threshold of the vectorial capacity equation. An increase in epidemic potential indicates that a smaller number of mosquitoes can maintain a state of endemicity of disease where dengue virus is introduced. Baseline climate data for comparison are from 1931 to 1980. Among the three GCMs| the average projected temperature elevation was 1.16 degrees C| expected by the year 2050. All three GCMs projected a temperature-related increase in potential seasonal transmission in five selected cities| as well as an increase in global epidemic potential| with the largest area change occurring in temper ate regions. For regions already at risk| the aggregate epidemic potential across the three scenarios rose on average between 31 and 47% (range| 24-74%). If climate change occurs| as many climatologists believe| this will increase the epidemic potential of dengue-carrying mosquitoes| given viral introduction and susceptible human populations. Our risk assessment suggests that increased incidence map first occur in regions bordering: endemic zones in latitude or altitude. Endemic locations may be at higher risk from hemorrhagic dengue if transmission intensity increases. 4499,1998,3,3,Development of CO2 recovery technology from combustion flue gas,As a countermeasure for global warming| the development of CO2 recovery technology from fossil fuel power plant flue gas has continued. MEA processes are widely used for CO2 recovery from combustion flue gas in beverage use| etc. However| ii we consider power plant scale CO2 recovery| the biggest theme is the reduction of energy needed to recover CO2. Our presentation focuses in sterically hindered amines and a new absorber packing. Also| the result uf optimum steam system analysis are indicated. CO2 disposal method is needed with the combination of CO2 recovery| therefore CO2 subterranean disposal method is also discussed as the practical way. 4662,1998,4,4,Diffusion coefficients of global warming gases into air and its component gases,The mutual diffusion coefficients of carbon dioxide| methane| and dinitrogen oxide into air and its component gases (nitrogen and oxygen) have been measured in the temperature range 0-180 degrees C and at atmospheric pressure by the use of the Taylor dispersion method. The diffusion Coefficients do not vary in practice on substituting pure nitrogen or oxygen for air. The diffusion coefficients for carbon dioxide and dinitrogen oxide| which have almost the same molecular weight| agree with each other within the experimental uncertainty (+/-2%)| and are smaller than those for methane. The present results can be reproduced well by the functional form D-12/m(2) s(-1) = A(T/K)(B)| where D-12 is the mutual diffusion coefficient at 1 atm (101 325 Pa) and Tis the absolute temperature. The constants A and B are as follows: carbon dioxide-lair| nitrogen| oxygen)| A = 5.75 x 10(-10)| B = 1.81; methane-(air| nitrogen| oxygen)| A = 7.04 x 10(-10) B = 1.83; dinitrogen oxide-(air| nitrogen| oxygen)| A = 5.34 x 10(-10)| B = 1.82. 4546,1998,5,3,Dinoflagellate-based sea surface temperature reconstructions across the Cretaceous-Tertiary boundary,Quantitative analysis of organic-walled dinoflagellate cyst (dinocyst) assemblages from closely spaced samples across the Cretaceous-Tertiary boundary (KTB) at El Kef (NW Tunisia)| Caravaca (SE Spain) and Stevns Klint (E Denmark) allows for reconstructions of sea surface temperature (SST) trends. The combined dinocyst-based SST curves indicate relatively stable warm conditions during the latest Maastrichtian in contrast to strongly fluctuating and on average cooler conditions during the earliest Danian. In detail| the results indicate cooling across the KTB| immediately followed by an interval of pronounced warming| the latter recorded in all studied sections. Two more cooling pulses may be recognized in the overlying interval followed by a gradual return to stable| relatively warm conditions. Our data furthermore show that these KTB-related climatic changes invoked distinct migration among organic-walled cyst-producing dinoflagellates| a group not pushed to extinction at the KTB| recordable in both hemispheres. Recent models predict periods varying between several months to 8-13 yr of global cooling ('impact winter') and reduced solar transmission as a direct result of the Chicxulub KTB impact| followed by relatively long-term| excess CO2-related global warming. Our results are in line with such models| but suggest that the impact-related cooling phase may have lasted longer| and that marked climatic instability continued to some 100|000 yrs following the KTB event(s). (C) 1998 Elsevier Science B.V. All rights reserved. 4582,1998,3,3,Direct conversion of methane to methanol using molten salts,In recent years the world has become more concerned about the global warming problem. The major greenhouse gas-CO2 are produced mainly by the utilization and combustion of fossil fuels-natural gas| oil| and coal. Methanol is a cleaner fuel for the environment than oil and coal. It generates less CO2| NOx and SOx per unit of thermal energy| and is easier to handle than methane. The direct conversion of methane to methanol is a potential process for methanol production| although it has not been practiced on a commercial level to date. In the present study| nitrate melts were used as the promoters for the partial oxidation of methane to methanol. The results were compared to the data extracted from the literature using other melt salts. It has been found that the oxygen-containing product CH3OH formed in nitrate melts| whereas the products obtained in hydroxides| carbonates and chlorides were mainly C2H6 and C2H4. Summarizing the results obtained in our work and the previous studies| it was suggested that the reaction route proceeding to the oxidative coupling or the direct conversion to methanol can be controlled by a suitable choice of molten salts. 4618,1998,3,3,Direct methanol fuel cells for vehicular applications,Dramatic technological advances for the proton exchange membrane fuel cell have focused attention on this technology for motor vehicles. The fuel cell vehicles (FCVs) have the potential to compete with the petroleum-fueled internal combustion engine Vehicles (ICEVs) in cost and performance while effectively addressing air quality| energy insecurity| and global warming concerns. Methanol being a liquid can be easily transported and can be supplied from the existing network of oil company distribution sites. Recently| combining improved catalysts with fuel cell engineering| it has been possible to overcome some of the difficulties that have frustrated previous research and development efforts in realizing a commercially viable direct methanol fuel cell. Direct methanol fuel cells (DMFCs) with power densities between 0.2 and 0.4 W/cm(2) at operational temperatures in the range 95-130 degrees C have been developed. These power densities are sufficient to suggest that stack construction is well worth while. This paper reviews recent advances and technical challenges in the field of DMFCs. 4648,1998,2,3,Does global warming threat the existence of Arctic charr| Salvelinus alpinus (Salmonidae)| in northern Finland?,Predicted global warming is expected to raise the water temperatures 2-6 degrees C after doubling of atmospheric CO2. As an extreme coldwater fish species the Arctic charr appear to avoid water temperatures above 16-18 degrees C. Arctic charr lives in Finland only in the mountain lakes of northernmost parts of the country and in some deep lakes of eastern Finland. Charr is most abundant at high altitudes. The global warming is expected to threaten first populations living in low altitude shallow lakes in which no thermal summer stratification occurs. Climatic warming will increase duration of high temperatures and thermal stratification in deep lakes. This indicates that Arctic charr will spend longer periods in minimum thermal habitats. Assuming that no factors other than temperature will change in future climates| reductions in summer habitat will probably lead to noticeable reductions in many charr populations. Populations living in deep lakes will survive better than those living in shallow lakes provided that the water quality of these lakes does not deteriorate. 4650,1998,4,3,Does the correlation between solar cycle lengths and Northern Hemisphere land temperatures rule out any significant global warming from greenhouse gases?,Since the discovery of a striking correlation between solar cycle lengths and Northern Hemisphere land temperatures there have been widespread speculations as to whether these findings would rule out any significant contributions to global warming from the enhanced concentrations of greenhouse gases. The present analysis shows that a similar degree of correlation is obtained when testing the solar data against a couple of fictitious temperature series representing different global warming trends. Therefore| the correlation cannot be used to estimate the magnitude of a possible contribution to global warming from human activities| nor to rule out a sizable contribution from that source. (C) 1998 Elsevier Science Ltd. All rights reserved. 2346,1998,2,3,Dynamic responses of terrestrial ecosystem carbon cycling to global climate change,Terrestrial ecosystems and the climate system are closely coupled| particularly by cycling of carbon between vegetation| soils and the atmosphere. It has been suggested(1|2) that changes in climate and in atmospheric carbon dioxide concentrations have modified the carbon cycle so as to render terrestrial-ecosystems as substantial carbon sinks(3|4); but direct evidence for this is very limited(5|6). Changes in ecosystem carbon stocks caused by shifts between stable climate states have been evaluated(7|8)| but the dynamic responses of ecosystem carbon fluxes to transient climate changes are still poorly understood. Here we use a terrestrial biogeochemical model(9)| forced by simulations of transient climate change with a general circulation model(10)| to quantify the dynamic variations in ecosystem carbon fluxes induced by transient changes in atmospheric CO2 and climate from 1861 to 2070. We predict that these changes increase global net ecosystem production significantly| but that this response will decline as the CO2 fertilization effect becomes saturated and is diminished by changes in climatic factors. Thus terrestrial ecosystem carbon fluxes both respond to and strongly influence the atmospheric CO2 increase and climate change. 4558,1998,4,2,Earth Observing System AM1 mission to earth,In 1998| NASA launches EOS-AM1| the first of a series of the Earth Observing System (EOS) satellites. EOS will monitor the evolution of the state of the earth for 18 years| starting with the morning observations of EOS-AM1 (10:30 a.m. equatorial crossing time). An integrated view of the earth| as planned by EOS| is needed to study the interchange of energy| moisture| and carbon between the lands| oceans| and atmosphere. The launch of EOS-AM1 and other international satellites marks a new phase of climate and global change research. Both natural and anthropogenic climate change have been studied for more than a century. It is now recognized that processes that vary rapidly in time and space-e.g| aerosol| clouds| land use| and exchanges of energy and moisture-must be considered to adequately explain the temperature record and predict future climate change. Frequent measurements with adequate resolution| as only possible from spacecraft| are key tools in such an effort. The versatile and highly accurate EOS-AM1 data| together with previous satellite records| as well as data from the Advanced Earth Observing System (ADEOS) (I and II)| Tropical Rainfall Measuring Mission (TRMM)| Sea-viewing Wide Field-of-view Sensor (SeaWiFS)| Along Track Scanning Radiometer (ATSR)| Medium Resolution Imaging Spectrometer (MERIS)| Environmental Satellite (ENVISAT)| EOS-PM1| Land Remote-Sensing Satellite (Landsat)| and ground-based networks is expected to revolutionize the way scientists look at climate change. This article introduces the EOS-AM1 mission and the special issue devoted to it. Following a brief historical perspective for an insight into the purpose and objectives of the mission| we shall summarize the characteristics of the five instruments onboard EOS-AM1. Specifically| we concentrate on the innovative elements of these five instruments and provide examples of the science issues that require this type of data. These examples show the importance of collecting data simultaneously from each of the five EOS-AM1 sensors for studying rapidly varying processes and parameters. 2372,1998,4,4,East Antarctic sea ice: observations and modelling,The importance of monitoring sea ice for studies of global climate has been well noted for several decades. Observations have shown that sea ice exhibits large seasonal variability in extent| concentration and thickness. These changes have a significant impact on climate| and the potential nature of many of these connections has been revealed in studies with numerical models. An accurate representation of the sea-ice distribution (including ice extent| concentration and thickness) in climate models is therefore important for modelling global climate change. This work presents an overview of the observed sea-ice characteristics in the East Antarctic pack ice (60-150 degrees E) and outlines possible improvements to the simulation of sea ice over this region by modifying the ice-thickness parameterisation in a coupled sea-ice-atmosphere model| using observational data of ice thickness and concentration. Sensitivity studies indicate that the simulation of East Antarctic sea ice can be improved by modifying both the "lead parameterisation" and "rafting scheme" to be ice-thickness dependent. The modelled results are currently out of phase with the observed data| and the addition of a multilevel ice-thickness distribution would improve the simulation significantly. 4543,1998,2,4,Effect of climate change on mast-seeding species: frequency of mass flowering and escape from specialist insect seed predators,Global surface temperatures are expected to increase by several degrees in the next century| with potentially large but poorly understood impacts on ecological interactions. Here we propose potential effects of increased temperatures on ecologically dominant New Zealand grasses (Chionochloa spp.) that mass flower and mast seed. Twenty-two years' data from five masting Chionochloa species in New Zealand showed that the cue for heavy flowering was unusually high temperature in the summer of the year before flowering. Attack by predispersal insect seed predators was much reduced in mast years| apparently because predator populations were satiated. Increased temperatures would greatly decrease interannual variation in Chionochloa flowering| allowing seed predator populations to increase and potentially to devastate the seed crop annually. Similar responses are likely in masting species worldwide. This previously unrecognized effect of global warming could have widespread impacts on temperate ecosystems. 4630,1998,3,4,Effect of crop management on C and N in long-term crop rotations after adopting no-tillage management: Comparison of soil sampling strategies,Society is interested in increasing C storage in soil to reduce CO2 concentration in the atmosphere| because the latter may contribute to global warming. Further| there is considerable interest in the use of straw for industrial purposes. Using soil samples taken from the 0- to 7.5-cm and 7.5- to 15-cm depths in May 1987 and September 1996| we determined organic C and total N in five crop rotations (nine treatments) using automated Carlo Erba combustion analyzer. The experiment was managed using conventional mechanical tillage from 1957 to 1989; it was changed to no-tillage management in 1990. Our objective was to determine: (a) if change to no-tillage management had changed soil C and N storage| and (b) if method of calculating organic C and N change would influence interpretation of the results. All three methods of calculation confirmed the efficacy of employing best management practices (e.g.| fertilization based on soil tests| reducing summerfallow| including legumes in rotations) for increasing or maintaining soil organic matter| and showed that the latter was directly associated with the amount of crop residues returned to the soil. Where bulk density was significantly different between sampling times| the often used mass per fixed depth (MFD) (i.e.| volume basis) calculation can lead to erroneous conclusions. When the recently recommended mass per equal depth (MED) method of calculation was used| it showed that 6 yr of no-tillage did not increase soil organic C or total N. However| in unfertilized systems| where crop yields are gradually decreasing since the change| there is an accompanying decrease in organic matter| while fertilized| or high-fertility systems that include legume hay crops| in which wheat yields have been maintained have tended to maintain the organic matter level over time. When the MFD calculation was used| there was no change in C over time when straw was harvested in the F-W-W system; however| the MED calculation and concentrations tend to show a decrease in soil C and N. This suggests that in time| industrial use of straw may have negative consequences for soil conservation. We concluded that concentrations may be as effective as MED for assessing changes in organic matter| provided "amounts" are not required. 4567,1998,3,4,Effect of soil oxidants KNO3| MnO2| and air on methane production in flooded rice soil suspension,To determine effective means to reduce methane (CH4) production from flooded rice soil| laboratory measurements were made on methane (CH4) formation in a Crowley silt loam as affected by the addition of potassium nitrate (KNO3)| manganese dioxide (MnO2)| and air (O-2) under flooded conditions. In the experiment| oxidants were added to the soil prior to flooding at the rate of 300 and 1000 ppm O-2 equivalent. Methane production was measured over a 32 d incubation period. Potassium nitrate added at rates of 300 and 1000 ppm O-2 equivalent reduced CH4 production by 100% and MnO2| at 300 and 1000 ppm O-2 equivalent| significantly decreased CH4 formation approximately 20% and 98-99% over the 32 d period| respectively compared to controls. Air addition did not significantly affect CH4 formation. 4571,1998,2,4,Effects of chronic sublethal ammonia and a simulated summer global warming scenario: protein synthesis in juvenile rainbow trout (Oncorhynchus mykiss),Protein synthesis| net accretion| and degradation in liver| gill| and white muscle and ribosomal translational efficiency and protein synthesis capacity in liver and gill were measured using a flooding dose of [H-3]phenylalanine in juvenile rainbow trout (Oncorhynchus mykiss). The fish were chronically exposed (90 days) in hardwater to the presence or absence of sublethal ammonia (70 mu mol total ammonia.L-1) alone or in combination with a 2 degrees C elevation in the normal temperature profile over the months of June-September 1993 (ambient temperature range 13-22 degrees C). Chronic sublethal exposure to ammonia had little impact on gill protein synthesis and degradation (protein turnover) and even less in muscle. However| in the liver| both protein synthesis and degradation were stimulated following 60 days of the sublethal ammonia exposure. The 2 degrees C elevation in temperature resulted in a slight increase in protein turnover in both gills and liver. However| during the period of peak water temperature| the 2 degrees C elevation in temperature inhibited protein dynamics in these tissues. Overall| elevated environmental ammonia in combination with a summer global warming scenario would challenge the ability of fish to adapt to alterations in the quality of their environment| most notably during periods of peak temperatures. 4570,1998,2,3,Effects of experimental warming on plant reproductive phenology in a subalpine meadow,Increasing "greenhouse" gases are predicted to warm the earth by several degrees Celsius during the coming century. At high elevations one likely result is a longer snow-free season| which will affect plant growth and reproduction. We studied flowering and fruiting of 10 angiosperm species in a subalpine meadow over 4 yr| focusing on plant responses to warming by overhead heaters. The 10 species reproduced in a predictable sequence during 3-4 mo between spring snowmelt and fall frosts. Experimental warming advanced the date of snowmelt by almost 1 wk on average| relative to controls| and similarly advanced the mean timing of plant reproduction. This phenological shift was entirely explained by earlier snowmelt in the case of six plant species I:hat flowered early in the season| whereas four later-flowering species apparently responded to other cues. Experimental warming had no detectable effect on the duration of flowering and fruiting| even though natural conditions of early snowmelt were associated with longer duration and greater overlap of reproduction of sequentially flowering species. Fruit set was greater in warmed plots for most species| but this effect was not significant for any species individually. We conclude that global warming will cause immediate phenological shifts in plant communities at high elevations| mediated largely through changes in timing of snowmelt. Shifts on longer time scales are also likely as plant fitnesses| population dynamics| and community structure respond to altered phenology of species relative to one another and to animal mutualists and enemies. However| the small spatial scale of experiments such as ours and the inability to perfectly mimic all elements of climate change limit our ability to predict these longer term changes. A promising future direction is to combine experiments with study of natural phenological variation on landscape and larger scales. 4659,1998,2,4,Effects of hydrologic changes on aboveground production and surface water chemistry in two boreal peatlands in Alberta: Implications for global warming,Aboveground net primary production (NPP) and surface water chemistry variables were monitored in a lacustrine sedge fen and a bog for four years. There were no significant differences in precipitation| mean growing season annual temperature| and number of growing degree days from 1991 to 1994. The mean annual water levels in the lacustrine sedge fen differed significantly| whereas they were similar in the bog during these four years. We measured 15 surface water variables in the lacustrine sedge fen and the bog| and found that only two correlated significantly with water level fluctuations. In the lacustrine sedge fen| calcium correlated positively (r(2) = 0.56) and nitrate correlated negatively (r(2) = 0.20) with water levels. In the bog| potassium correlated positively (r(2) = 0.88) and total dissolved phosphorus correlated negatively (r(2) = 0.62) with water levels. The remaining chemical variables showed no significant correlations with water level fluctuations. Net primary production of the different vegetation strata appeared to respond to different environmental variables. In the lacustrine sedge fen| graminoid production was explained to a significant degree by water levels (r(2) = 0.53)| whereas shrub production was explained to a significant degree by surface water chemistry variables| such as nitrate (r(2) = 0.74) and total phosphorus (r(2) = 0.22). In the bog| temperature was the only variable that explained moss production to a significant degree (r(2) = 0.71)| whereas ammonium explained graminoid production (r(2) = 0.66) and soluble reactive phosphorus explained shrub production to significant degrees (r(2) = 0.71). There are few direct data on the impact of climatic warming in boreal wetlands| although paleoecological and 2xCO(2) model data have provided some indications of past and possibly future changes in vegetation composition| respectively. Our results suggest that the lacustrine sedge fen may succeed to a bog dominated by Sphagnum spp. and Picea mariana| whereas the bog may succeed to an upland-type forest ecosystem. 4486,1998,3,4,Effects of including nitrogen emissions from soil in environmental systems analysis of waste management strategies,The environmental impacts of nitrogen emissions from soil resulting from the use of organic fertilizers| such as manure| are large compared with the corresponding impacts of mineral fertilizers. However| soil emissions are rarely included in systems analysis of waste management strategies. This study examines whether the inclusion of soil emissions can affect the environmental ranking of systems for managing solid biodegradable waste. Waste management scenarios based on incineration| anaerobic digestion and composting| respectively| were compared. The scenarios were analysed using the organic waste research (ORWARE) simulation model. A simplified model for calculating nitrogen availability and emissions was also constructed. Life-cycle analysis methodology was used for choosing system boundaries and evaluating the results. Global warming| acidification and eutrophication were the impact categories considered. The results indicate the vital importance of considering nitrogen emissions from soil when comparing biological waste management systems with other waste management methods| especially with regard to eutrophication effects. Soil emissions are also important when comparing the environmental impacts of anaerobic digestion and composting systems. However| the variation in nitrogen emissions from soil is large and depends on the spreading technique used| climate| drainage and soil texture (C) 1998 Elsevier Science B.V. All rights reserved. 2354,1998,4,4,Effects of long-term elevated [CO2] from natural CO2 springs on Nardus stricta: Photosynthesis| biochemistry| growth and phenology,Plants of Nardus stricta growing near a cold| naturally emitting CO2 spring in Iceland were used to investigate the long-term (> 100 years) effects of elevated [CO2] on photosynthesis| biochemistry| growth and phenology in a northern grassland ecosystem. Comparisons were made between plants growing in an atmosphere naturally enriched with CO2 (approximate to 790 mu mol mol(-1)) near the CO2 spring and plants of the same species growing in adjacent areas exposed to ambient CO2 concentrations (approximate to 360 mu mol mol(-1)). Nardus stricta growing near the spring exhibited earlier senescence and reductions in photosynthetic capacity (approximate to 25%)| Rubisco content (approximate to 26%)| Rubisco activity (approximate to 40%)| Rubisco activation state (approximate to 23%)| chlorophyll content (approximate to 33%) and leaf area index (approximate to 22%) compared|vith plants growing away from the spring. The potential positive effects of elevated [CO2] on grassland ecosystems in Iceland are likely to be reduced by strong down-regulation in the photosynthetic apparatus of the abundant N| stricta species. 4537,1998,4,4,Effects of orbital decay on satellite-derived lower-tropospheric temperature trends,The 17-year lower-tropospheric temperature record derived from the satellite Microwave Sounding Unit (MSU)(1-3) shows a global cooling trend| from 1979 to 1995| of -0.05 K per decade at an altitude of about 3.5 km (refs 4| 5). Air temperatures measured at the Earth's surface| in contrast| have risen by approximately +0.13 K per decade over the same period(4|6). The two temperature records are derived from measurements of different physical parameters| and thus are not directly comparable. In fact| the lower stratosphere is cooling substantially (by about -0.5 K per decade)(5)| so the warming trend seen at the surface is expected to diminish with altitude and change into a cooling trend at some point in the troposphere. Even so| it has been suggested that the cooling trend seen in the satellite data is excessive(4|7|8). The difficulty in reconciling the information from these different sources has sparked a debate in the climate community about possible instrumental problems and the existence of global warming(4|7|9). Here we identify an artificial cooling trend in the satellite-derived temperature series caused by previously neglected orbital-decay effects. We find a new| corrected estimate of +0.07 K per decade for the MSU-based temperature trend| which is in closer agreement with surface temperatures. We also find that the reported(7) cooling of the lower troposphere| relative to the middle troposphere| is another artefact caused by uncorrected orbital-decay effects. 4667,1998,3,4,Effects of water percolation on methane emission from rice paddies: a lysimeter experiment,The effect of water percolation on CH4 emission from rice paddies was investigated using a lysimeter experiment for 4 years. Water percolation rates of the lysimeters were adjusted to one of three values| about 0| 5| or 20 mm day(-1) during the cultivation periods of the first 3 years by periodically opening water stopping valves installed at the bottom of the lysimeters. In the 4th year| water was drained by pumps at a rate of 0| 7.7| or 25 mm day(-1) respectively. CH4 emission rates significantly decreased with an increase in the percolation rates. Total emission during a cultivation period ranged from 5.7 to 13.8| 0.6 to 4.8| and 0.1 to 0.3 g m(-2) in the no-| moderate-| and high-percolation plots| respectively. The decrease in soil Eh during the cultivation periods was markedly retarded by water percolation. The critical initiation soil Eh of CH4 emission observed was around -30 mV at 5 cm depth. CH4 emissions during the fallow periods (from September to May) were equivalent to 14-18% of those during the previous cultivation period if the paddies were continuously flooded all the year round. Low soil temperature during the fallow periods was a major limiting factor for CH4 emission during these periods in the case of continuously flooded treatment. 4574,1998,2,3,El Nino| ice cover| and Great Lakes phosphorus: Implications for climate warming,Phosphorus concentrations in a 19-year record of the Lake Huron outflow (Laurentian Great Lakes of North America) were negatively correlated with the extent of Great Lakes winter ice cover. The highest phosphorus concentrations (2-3 times higher than normal) occurred during 1983| 1987| and 1992 in response to strong El Nino-related moderation of winter air temperatures. The 1983 winter air temperature anomaly of +2.5 degrees C (the mildest winter in the record) is well within the output of predicted temperature increases by general circulation models for the Great Lakes basin under a 2X CO2 climate warming scenario. Lake data from strong El Nino years| when contrasted with other years having near-normal winter temperatures and ice cover| can thus serve to identify some previously unanticipated impacts of global warming on lake water quality. I suggest that global warming may have important implications for eutrophication control in the Great Lakes. 2345,1998,2,4,Elevated atmospheric [CO2] promotes frost damage in evergreen tree seedlings,Growth under elevated [CO2] promoted spring frost damage in field grown seedlings of snow gum (Eucalyptus pauciflora Sieb| ex Spreng|)| one of the most frost tolerant of eucalypts| Freezing began in the leaf midvein| consistent with it being a major site of frost damage under field conditions. The average ice nucleation temperature was higher in leaves grown under elevated [CO2] (- 5.7 degrees C versus - 4.3 degrees C)| consistent with the greater incidence of frost damage in these leaves (34% versus 68% of leaves damaged). These results have major implications for agriculture| forestry and vegetation dynamics| as an increase in frost susceptibility may reduce potential gains in productivity from CO2 fertilization and may affect predictions of vegetation change based on increasing temperature. 2341,1998,2,4,Elevated CO2 and water deficit effects on photosynthesis| ribulose bisphosphate carboxylase-oxygenase| and carbohydrate metabolism in rice,Rice (Oryza sativa [L.] cv. IR-72) was grown for a season in sunlit| controlled-environment chambers at 350 or 700 mu mol CO2 mol(-1) under continuously flooded (unstressed) or drought-imposed periods at panicle initiation (stressed). The midday canopy photosynthetic rates (P-n)| measured at the CO2 concentration ([CO2]) used for growth| were enhanced by high [CO2] but reduced by drought. High [CO2] increased P-n by 18 to 34% for the unstressed plants| and 6 to 12% for the stressed plants. In the unstressed plants| CO2 enrichment increased water-use efficiency (WUE) by 26%| and reduced evapotranspiration (ET) by 8 to 14%. Both high [CO2] and severe drought decreased the activity and content of ribulose bisphosphate carboxylase-oxygenase (Rubisco). High-CO2-unstressed plants had 6 to 22% smaller content and 5 to 25% lower activity of Rubisco than ambient-CO2-unstressed plants. Under severe drought| reductions of Rubisco were 53 and 27% in activity and 40 and 12% in content| respectively| for ambient- and high-CO2 treatments. The apparent catalytic turnover rate (K-cat) of midday fully activated Rubisco was not altered by high [CO2]| but severe drought reduced K-cat by 17 to 23%. Chloroplasts of the high-CO2 leaves contained more| and larger starch grains than those of the ambient-CO2 leaves. High [CO2] did not affect the leaf sucrose content of unstressed plants. In contrast| severe drought reduced the leaf starch and increased the sucrose content in both CO2 treatments. The activity of leaf sucrose phosphate synthase of unstressed plants was not affected by high [CO2]| whereas that of ambient-CO2-grown plants was reduced 45% by severe drought. Reduction in ET and enhancements in both P-n and WUE for rice grown under high [CO2] helped to delay the adverse effects of severe drought and allowed the stressed plants to assimilate CO2 for an extra day. Thus| rice grown in the next century may utilize less water| use water more efficiently| and be able to tolerate drought better under some situations. 4510,1998,3,4,Emissions of N(2)O from Scottish agricultural soils| as a function of fertilizer N,Potato fields and cut (ungrazed) grassland in SE Scotland gave greater annual N(2)O emissions per ha (1.0-3.2 kg N(2)O-N ha(-1)) than spring barley or winter wheat fields (0.3-0.8 kg N(2)O-N ha(-1))| but in terms of emission per unit of N applied the order was potatoes > barley > grass > wheat. On the arable land| especially the potato fields| a large part of the emissions occurred after harvest. When the grassland data were combined with those for 2 years' earlier work at the same site| the mean emission over 3 years| for fertilization with ammonium nitrate| was 2.24 kg N(2)O-N ha(-1) (0.62% of the N applied). Also| a very strong relationship between N(2)O emission and soil nitrate content was found for the grassland| provided the water-filled pore space was > 70%. Significant relationships were also found between the emissions from potato fields and the soil mineral N content| with the added feature that the emission per unit of soil mineral N was an order of magnitude larger after harvest than before| possibly due to the effect of labile organic residues on denitrification. Generally the emissions measured were lower| as a function of the N applied| than those used as the basis for the current value adopted by IPCC| possibly because spring/early summer temperatures in SE Scotland are lower than those where the other data were obtained. The role of other factors contributing to emissions| e.g. winter freeze-thaw events and green manure inputs| are discussed| together with the possible implications of future increases in nitrogen fertilizer use in the tropics. 4540,1998,3,3,Environmental aspects of fluorinated materials: Part 3 - Comparative life-cycle assessment of the impacts associated with fire extinguishants HFC-227ea and IG-541,Fluorinated materials developed to replace materials banned from manufacture under the Montreal Protocol are themselves contributors to environment damage. In particular| their contribution go global warming is under scrutiny from customers| regulators and pressure groups. This paper provides a comparison of the global warming and other impacts associated with two possible replacements for Halon 1301 (a banned fire extinguishant)| namely an 'in-kind' compound CF3CHFCF3 (HFC-227ea) and a 'not-in-kind' blend of nitrogen| argon and carbon dioxide (IG-541). The impacts associated with the manufacture and deployment of the HFC-227ea are found to be substantially greater than those of the inert gas mixture designed for the same fire-extinguishing duty. The impacts during manufacture reveal an important issue for the widely used measure of global warming impact-the so-called Total Equivalent Warming Impact (TEWI). The present work clearly reveals that where impacts associated with manufacture are significant| the scope of the TEWI analysis needs to cover the manufacturing process if it is to be meaningful. 2317,1998,4,3,European source strengths and northern hemisphere baseline concentrations of radiatively active trace gases at Mace Head| Ireland,Greenhouse gas measurements have been made continuously with high frequency and precision at the remote baseline monitoring station at Mace Head on the Atlantic Ocean coastline of Ireland since 1987. By using three independent methods| the two-hourly observations have been sorted by air mass origins into those from "unpolluted" or Northern Hemisphere baseline air masses and those from "polluted" European air masses. Northern Hemisphere baseline methane| nitrous oxide and carbon dioxide concentrations have risen throughout the 10 year period and their respective mid-1996 levels are the highest mid-year levels recorded so far. For ozone| the mid-1996 annual mean concentrations was within 0.1 ppb of the highest mid-year level. The elevated greenhouse gas concentrations found in "polluted" air masses provide clear evidence for the presence of substantial emission sources in Europe. Using a simple climatological long-range transport model and a sophisticated Lagrangian dispersion model| it has been possible to estimate the magnitudes of the greenhouse gas emissions required to support the observations. Estimates of European source strengths of methane| nitrous oxide| carbon monoxide and halocarbons agree well with the available emission inventories. Using the Mace Head observations| significant additional contributions to global climate change have been identified from the trace gases: methane| nitrous oxide and tropospheric ozone| over and above that driven by carbon dioxide. The radiative forcing consequences of a range of HCFCs and HFCs will only become of significance should their emissions grow to become comparable with those of the CFCs that they have replaced. (C) 1998 Elsevier Science Ltd. All rights reserved. 4598,1998,3,3,Evaluation of trifluoroacetic anhydride as an alternative plasma enhanced chemical vapor deposition chamber clean chemistry,One environmental issue currently facing the semiconductor industry is the emission of perfluorinated compounds (PFCs) from a variety of processes including chamber cleaning following plasma enhanced chemical vapor deposition (PECVD) of dielectrics. The emission of PFCs has been targeted for reduction due to the contribution of these species to global warming. An option under investigation is the use of alternative compounds that emit lower amounts of global warming species. The current study presents chamber cleaning times and emissions from the use of one such species| trifluoroacetic anhydride (TFAA)| in a widely used commercial PECVD tool| the Novellus Concept One 200. A central composite design-of-experiments was employed to calculate response surfaces for the chamber clean time and PFC emission concentrations as the chamber pressure| TFAA flow rate| and oxygen flow rate were varied. The chamber clean times were measured using optical emission spectroscopy| quadrupole mass spectrometry| as well as Fourier transform infrared (FTIR) spectroscopy| and the PFC emissions were quantified using FTIR spectroscopy. The performance of TFAA is compared to standard Novellus Concept One 200 C2F6 and C3F8 chamber cleaning processes and to processes in which the effect of augmentation of C2F6 with NF3 is studied. (C) 1998 American Vacuum Society. 4563,1998,3,3,Evaluation of trifluoroiodomethane as SiO2 etchant for global warming reduction,The utilization of CF3I in the plasma assisted dry etching of SiO2 has been studied in order to reduce the environmental impact of microelectronics device fabrication. The results show that CF3I is a promising substitute of CF4 in oxide etching since its utilization reduces 3-3.5 times the contribution to the global warming| nevertheless it still has a consistent effect on the environment for the plasma assisted formation of perfluorocompounds. (C) 1998 American Vacuum Society. 4584,1998,4,4,Evidence for solar-cycle forcing and secular variation in the Armagh Observatory temperature record (1844-1992),A prominent feature of previous long-term temperature studies has been the appearance of warming since the 1880s| this often being taken as evidence for anthropogenic-induced global warming. In this investigation| the long-term| annual| mean temperature record (1844-1992) of the Armagh Observatory (Armagh| North Ireland)| a set of temperature data based on maximum and minimum thermometers that predates the 1880s and correlates well with northern hemispheric and global standards| is examined for evidence of systematic variation| in particular| as related to solar-cycle forcing and secular variation. Indeed| both appear to be embedded within the Armagh data. Removal of these effects| each contributing about 8% to the overall reduction in variance| yields residuals that are randomly distributed. Application of the 10-year moving average to the residuals| furthermore| strongly suggests that the behavior of the residuals is episodic| inferring that (for extended periods of time) temperatures at Armagh sometimes were warmer or cooler (than expected)| while at other times they were stable. Comparison of cyclic averages of annual mean temperatures against the lengths of the associated Hale cycles (i.e.| the length of two| sequentially numbered| even-odd sunspot cycle pairs) strongly suggests that the temperatures correlate inversely (r = -0.886 at <2% level of significance) against the length of the associated Hale cycle. Because sunspot cycle 22 ended in 1996| the present Hale cycle probably will be shorter than average| implying that temperatures at Armagh over this Hale cycle will be warmer (about 9.31 +/- 0.23 degrees C at the 90% confidence level) than average (= 9.00 degrees C). 4578,1998,2,4,Extreme erosional events and natural hazards in Scandinavian mountains,The climate in northwestern Europe in the last 50 years appears to have undergone periods of marked extreme events such as windstorms| snowstorms and events of heavy rainfall| causing floods and erosion. In particular| the summers in the 1990s had Mediterranean-like fluctuations with warm spells| rainstorms of "double" intensity| flooding| and landslides in the mountains. If and how these extremes are connected with global warming due to an increasing greenhouse effect is an open question. However| we feel justified| both for theoretical and practical reasons| in making the following recommendations for future research: Continued observation and information on extreme erosional events and natural hazards are important in order to clarify their climatic links and for safer environmental management for the benefit of people who work or are tourists in the mountains and downstream areas. It is also necessary to improve our knowledge of the connections between local weather extremes and regional climatic trends| e.g. through reconstruction of the former frequency of events during periods of rising temperatures. Two kinds of erosional processes and natural hazards| which may increase in frequency during a climatic warming| are discussed: i) snowmelt-triggered floods and slushflows in spring; and ii) rainstorm-triggered floods and debris flows in summer and autumn. 4621,1998,2,4,Flowering phenology in the central highland of Iceland and implications for climatic warming in the Arctic,The cool and short growing season that characterizes Arctic climates puts severe constraints on life cycles and reproduction in the Arctic flora. The timing of flowering is particularly critical and may affect both breeding system and reproductive success through the heavy penalties associated with later flowering. An 11-year study of 75 species in the central highland of Iceland showed that the onset of flowering varies greatly among years. The number of species in flower by the first week of July was closely correlated with air temperature (degree days above zero) in the preceding 5 weeks| but no correlations were found with degree days in May or with total degree days in the previous growing season. Time of snowmelt| which has widely been regarded as the environmental event initiating growth and flowering in alpine and arctic tundra| only had a significant effect when two exceptionally cold and late summers were included. The species studied| most of which have a wide distribution in the Arctic| are predicted to respond quickly to warmer spring and early summer temperatures. Accelerated phenologies may alter patterns of resource allocation| have implications for pollinators and pollinator-competition| and could increase the size| species richness and intraspecific genetic diversity of the soil seed bank. 4522,1998,3,4,Fluorocarbons and sulfur hexafluoride (SF6): A methodology for national emission inventories and scenarios applied to the Netherlands,A six-step methodology for estimating use (Steps 1-5) and emissions (Step 6) of fluorocarbons not regulated under the Montreal Protocol and SF6 has been described| to improve insight into emissions in the Netherlands. The last step is largely in line with methods applied in the annual AFEAS reports and under discussion within the IPCC| and estimates HFCs| PFCs| FICs and SF6 released as the sum of (1) emission from compounds used as substitutes for ozone-depleting compounds (2) emissions due to SF6's historical market and (3) emissions from other industrial processes. Emissions in the Netherlands were estimated for scenarios assuming that the Montreal protocol will be implemented. Without additional measures (reference scenario emissions of HFCs| PFCs| FICs and SF6 increase from 878 (metric) tons in 1990 to 6983 tons in 2020. In 2020 emissions are estimated to be about 21 Mt CO2 equivalents| or 13% of the CO2 target for that year (i.e. stabilization at the 2000 level). Assuming maximum emission control through good housekeeping| recycling and waste destruction| emissions are 40-50% lower than in the no-control scenarios. The closed applications only scenario assumes use of these compounds to be restricted to stationary cooling and closed-foam blowing. In this scenario| emissions are 15-25% (no-control case) and 50-60% (maximum emission control case) lower than in the reference scenario. Reductions up to 90% are found in the low-GWP scenario| assuming an average Global Warming Potential of the mix of compounds used of 250 or less. 4526,1998,3,2,Fluxes of carbon dioxide| nitrous oxide| and methane in grass sod and winter wheat-fallow tillage management,Cropping and tillage management can increase atmospheric CO2| N2O| and CH4 concentrations| and contribute to global warming and destruction of the ozone layer. Fluxes of these gases in vented surface chambers| and water filled pore space (WFPS) and temperature of survace soil were measured weekly from a long-term winter wheat (Triticum aestivum L.)-fallow rotation system under chemical (no-tillage) and mechanical tillage (noninversion subtillage at 7 to 10 cm or moldboard plowing to 15 cm) follow management and compared with those from "native" grass sod at Sidney| NE| from March 1993 to July 1995. Cropping| tillage| within-field location| time of year| soil temperature| and WFPS influenced net greenhouse gas fluxes. Mean annual interrow CO2 emissions from wheat-fallow ranged from 6.9 to 20.1 kg C ha(-1) d(-1) and generally increased with intensity and degree of tillage (no-till least and plow greatest). Nitrous oxide flux averaged <1.2 g N ha(-1) d(-1) for sod and 1 to 2 g N ha(-1) d(-1) for wheat-fallow. Tillage during fallow increased NIO flux by almost 100%. Nitrous oxide emissions were 1.5 to 3.7 times greater from crop row than interrow locations with greatest differences occurring during periods of highest N2O emission. Mean annual N2O flux over the 3 Jr of study were 1.54 and 0.76 g N ha(-1) d(-1) for row and interrow locations. Methane uptake ranged from 5.9 to 9.9 g C ha(-1) d(-1) and was not influenced by row location. Seasonal CO2 and N2O flux| and CH4 uptake ranked as spring greater than or equal to summer > autumn > winter. Winter periods accounted for 4 to 10% and 3 to 47% of the annual CO2 and N2O flux| respectively| and 12 to 21% of the annual CH4 uptake. Fluxes of CO2 and N2O| and CH4 uptake increased linearly with soil temperature. No-till fallow exhibited the least threat to deterioration of atmospheric or soil quality as reflected by greater CH4 uptake| decreased N2O and CO2 emissions| and less loss of soil organic C than tilled soils. However| potential for increased C sequestration in this wheat-fallow system is limited due to reduced C input from intermittent cropping. 4610,1998,2,4,Foliar carbon isotope discrimination in Larix species and sympatric evergreen conifers: a global comparison,Larches (Larix spp.)| deciduous conifers| occur in the northern hemisphere in cold-temperate and boreal climates - an environment normally thought to favor ever-green tree species. We compare foliar carbon isotope discrimination (Delta)| instantaneous water use efficiency| total foliar nitrogen concentration| and specific leaf area (for a subset of sites) between Larix spp. and co-occurring evergreen conifers at 20 sites throughout the natural range of larches. Except for Larix occidentalis in the xeric Intermountain West| USA| Delta is significantly (P < 0.05) greater for larches than co-occurring evergreen conifers at 77% of the sites| suggesting that larches use water less efficiently. At elevations greater than 3000 m| the Delta of Lar ix-spp. and co-occurring conifers converge| suggesting that water is not the limiting resource. Foliar nitrogen concentration and specific leaf area are two ecophysiological characteristics that are positively correlated with high photosynthetic capacity. Foliar nitrogen concentration is significantly greater for larches than evergreen conifers at 88% of the sites and specific leaf area is approximately three times greater for larches than co-occurring conifers. Future studies should examine the potential effect that global warming may have on the distribution of larch forests because the water use efficiency of larches is commonly less than cooccurring evergreen conifers and the boreal and high-latitude environments are likely to experience the greatest climate warming. 4629,1998,5,4,Forest fire and lake-water acidity in a northern Swedish boreal area: Holocene changes in lake-water quality at Makkassjon,1 A Holocene sediment profile from a northern Swedish boreal forest lake was analysed for diatoms| pollen and charcoal. The diatom data were used for inferences of lake-water pH| alkalinity and colour| while the pollen and charcoal records enabled assessment of catchment vegetation changes and fire. This palaeoecological study demonstrated long-term changes in lake-water acidity as a result of catchment vegetation changes and fire. 2 The pollen record showed the transition from a deciduous-dominated forest (Betula and Alnus) 9000-8000 years sp (calibrated years) to the present coniferous-dominated forest (mainly Pinus) in the catchment of Makkassjon. Local peaks in the steadily decreasing Betula pollen curve corresponded with increases in the charcoal concentration. Picea pollen did not appear until the uppermost half of the sediment section (c. 2500 sp)| and never exceeded 10% relative abundance. 3 The Holocene development in lake-water chemistry| inferred from diatom analysis| was divided into three periods: a natural acidification| a natural alkalization and a fertilization/liming period. During the long-term natural acidification period| the diatom-inferred pH and alkalinity decreased by c. 1.3 pH units and c.80 mu eq I-L| respectively| while diatom-inferred colour increased from 10 to 40 mg Pt 1(-1) in the same period. These changes occurred simultaneously with a change from deciduous to coniferous forest. Using redundancy analysis (RDA) with the tree pollen as predictor variables| the Alnus| Betula or Pinus pollen record captured 41-85% of the variance in lake-water pH and alkalinity. 4 During the period of natural alkalization fire became a dominant disturbance factor in the catchment. The charcoal record was a significant predictor of the variance in diatom-inferred pH and alkalinity during the period with frequent fires| as determined by RDA analysis with a time-restricted Monte Carlo permutation test. The inferred changes in pH and colour suggested that the reduction of soil humus played a major role in the alkalization of the acid-sensitive lake. 5 The results highlight questions about the important mechanisms for predicting the long-term effects of fire on surface-water chemistry| which will be of crucial importance if changes in fire regime take place as a consequence of global warming. 2316,1998,2,2,Forests of tomorrow - from a climatologist's viewpoint,Global climate changes in the course of the past 100 years| that form part of the global environmental changes| are recognizable by a number of indications and can be attributed - to a statistically significant degree - to the: anthropogenic greenhouse effect. These climate changes have clear effects on the biosphere: For example| lengthening of the growing season| as shown by indirect and direct observations as well as by phenological models. The forest of tomorrow will be exposed to a number of further climate changes| with likely different consequences for the main tree species. 4507,1998,4,4,Fundamental study of LCA method for electrical appliances and office automation equipment,In order to develop a life cycle assessment method| which can be widely applied to electrical appliances and office automation equipment we have investigated resource depletion| energy consumption| and environmental pollution in the manufacturing process of circuit boards| and we have identified the common units| such as 228 Mcal/kg of energy consumption and 15.979 kg-C/kg of carbon dioxide emission. Using these common units| we have calculated the categorized impact for the environment (resource depletion| global warming| acid rain| and atmospheric pollution) using a laptop personal computer| whose processing speed (PS) is improved by 5 times| weight is decreased by 47%| and energy-consumption is cut by 44%| compared with previous type. We have also shown that the life cycle environmental impact (EI) per personal computer decreases by 38% in resource depletion| life cycle EI per processing speed decreases 87% in all categories| and environmental efficiency (=PS/EI) in all categories improves by a factor of approximately eight (factor value: 8). 4539,1998,2,4,Future wildfire in circumboreal forests in relation to global warming,Despite increasing temperatures since the end of the Little Ice Age (ca. 1850)| wildfire frequency has decreased as shown in many field studies from North America and Europe. We believe that global warming since 1850 may have triggered decreases in fire frequency in some regions and future warming may even lead to further decreases in fire frequency. Simulations of present and future fire regimes| using daily outputs from the General Circulation Model (GCM)| were in good agreement with recent trends observed in fire history studies. Daily data| rather than monthly data| were used because the weather and| consequently| fire behavior can change dramatically over time periods much shorter than a month. The simulation and fire history results suggest that the impact of global warming on northern forests through forest fires may not be disastrous and that| contrary to the expectation of an overall increase in forest fires| there may be large regions of the Northern Hemisphere with a reduced fire frequency. 4651,1998,4,5,Geomagnetic forcing of changes in climate and in the atmospheric circulation,Common features in records of solar and geomagnetic activity as well as of climatic parameters can be observed. High correlation coefficients were Found between geomagnetic activity| the sea level atmospheric pressure and the surface air temperature| occurring with a positive sign in the middle and southern Europe| in the south-eastern part of North America and in the western Atlantic but with a negative sign in the northern Atlantic and Canada. In the hypothesis proposed here for explaining Sun-weather relations| downward winds following the geomagnetic storm onset are generated in the polar cap of the thermosphere and penetrate to the stratosphere and troposphere| where the atmospheric response can be observed as a sudden increase of pressure and temperature. The subsidence effects along the northern margin of the subpolar high pressure areas (mainly the Siberian high) are accelerated and strong eastward winds participate in the intensification of the northern jet stream and in the successive zonalization of how in mid-latitudes. It is shown that at a time of low geomagnetic activity planetary waves with large amplitudes prevail in the northern hemisphere due to the orographic effect of the Rocky Mountains and Greenland. On the other hand| at a lime of high geomagnetic activity| an intensification of the winds can be observed not only in the thermosphere but also in the troposphere. A strong northern jet stream participates in the intensification of the westerly zonal flow and in the increase of temperature successively in the eastern part of North America| in Europe and northern Asia. These relations are clearly detectable not only in monthly averages of the pressure and temperature distribution but also in the daily variations of atmospheric circulation. The results enable us to test a causal link of the Sun-weather processes| to explain strong interannual climate and weather changes in several key regions of the northern hemisphere| mainly in winter| and to study possible causes of the North Atlantic Oscillation. The results obtained contribute also to the study of the occurrence of long-term cyclic changes which were observed both in solar and geomagnetic activity and temperature T| as well as in the radioactive Delta(14)C| and have a similar trend. A composite curve was suggested by summing up sinusoidal curves with periods 70| 200| 800 and 2400 years roughly representing changes of all three mentioned parameters (aa| T and Delta(14)C) during the past 1600 years and their probable trend for the next 800 years. The results seem to imply that the global warming could be slowed down in next decades| because the natural component influencing the increase of temperature in the 20th century will most probably decrease in the next century due to the weaker external geomagnetic forcing which was suggested to modify natural meteorological processes. (C) 1998 Elsevier Science Ltd. All rights reserved. 2355,1998,2,3,Global average climate forcing and temperature response since 1750,Estimates are made for the period since 1750 of the major radiative forcing factors thought to be important in climate change. Analysis of these emphasizes the role of biospheric CO2 release and increasing methane up to the early twentieth century. Fossil fuel burning had a minor role until the mid-twentieth century| with the relatively small effects of fossil fuel CO2 being cancelled by sulphate aerosols from the same source. It is shown that| by using reasonable estimates of the contributions by greenhouse gases and anthropogenic and volcanic aerosols| a simple box-diffusion climate model simulates many features of the observed record of global climate change as estimated from both instrumental and glacier data. This is achieved without including either variations in solar intensity over this period or internal variability-which recent discussions of the topic have suggested are needed-but including forcing by volcanic aerosols| which these studies neglected. Three different estimates of forcing by volcanic aerosols are considered; although the volcanic aerosols substantially improve the model's fit to the observations| the validation does not show any one estimate to be clearly superior. The temperature record is shown to be consistent with the climate sensitivity obtained with three-dimensional models. (C) 1998 Royal Meteorological Society. 2335,1998,2,4,Global climate change and infectious diseases,Climate change| if it occurs at the level projected by current global circulation models| may have important and far-reaching effects on infectious diseases| especially those transmitted by poikilothermic arthropods such as mosquitoes and ticks. Although most scientists agree that global climate change will influence infectious disease transmission dynamics| the extent of the influence is uncertain. This conference session provided an overview of the issues associated with climate change as it relates to the emergence and spread of infectious diseases.
2328,1998,3,4,Global climate change and the challenges for renewable energy,Despite the recent encouraging signs of interest by major industrial firms in developing renewable energy sources and technologies more quickly and on a large scale| the 1990s have so far on balance given little grounds for optimism. This is because of the slowness of effective policy developments in the wake of lack of real public support and commitments which has increased pessimism in relation to: prospects for raising the efficiency of energy use quickly; prospects for expanding renewable energy resource utilization quickly; and curbing greenhouse gas emissions and mitigating climate change. Further discussions on these issues are presented. 2337,1998,2,4,Global climate change and tropical forest genetic resources,Global climate change may have a serious impact on genetic resources in tropical forest trees. Genetic diversity plays a critical role in the survival of populations in rapidly changing environments. Furthermore| most tropical plant species are known to have unique ecological niches| and therefore changes in climate may directly affect the distribution of biomes| ecosystems| and constituent species. Climate change may also indirectly affect plant genetic resources through effects on phenology| breeding systems| and plant-pollinator and plant seed disperser interactions| and may reduce genetic diversity and reproductive output. As a consequence| population densities may be reduced leading to reduction in genetic diversity through genetic drift and inbreeding. Tropical forest plants may respond to climate change through phenotypic plasticity| adaptive evolution| migration to suitable site| or extinction. However| the potential to respond is limited by a rapid pace of change and the non-availability of alternate habitats due to past and present trends of deforestation. Thus climate change may result in extinction of many populations and species. Our ability to estimate the precise response of tropical forest ecosystems to climate change is limited by lack of long-term data on parameters that might be affected by climate change. Collection of correlative data from long-term monitoring of climate as well as population and community responses at selected sites offer the most cost-effective way to understand the effects of climate change on tropical tree populations. However| mitigation strategies need to be implemented immediately. Because many effects of climate change may be similar to the effects of habitat alteration and fragmentation| protected areas and buffer zones should be enlarged| with an emphasis on connectivity among conserved landscapes. Taxa that are likely to become extinct should be identified and protected through at situ conservation programs. 2369,1998,2,2,Global climate change: Lessons from the past - policy for the future,The Intergovernmental Panel on Climate Change (IPCC) recently published its second scientific assessment of climate change. Central to the findings of this study is the statement that "the balance of evidence suggests a discernible human influence on global climate" This statement arose from recent studies which compared the observational record over the last century with the results from numerical modelling simulations of the climatic response to increasing greenhouse gases and anthropogenic sulphate aerosols. It has profound implications for policy makers as it is the first time that IPCC has stated that global warming has been detected in the observational record. Recent modelling studies reported in the IPCC second assessment also suggest "best estimates" of 2 degrees C warming and 50 cm sea level rise by the year 2100| relative to 1990| with amplification of the warming at high latitudes and over the interior of continents. Similar IPCC "best estimates" of emission scenarios suggest that the atmospheric concentration of carbon dioxide will continue to increase over the next few centuries. Stabilization of atmospheric carbon dioxide levels| even as high as three times the present| require emission levels significantly below those of 1990. In this paper| the observational record is briefly reviewed as are the recent modelling results which have lead to the statements above. Particular emphasis is given to the role of the oceans in climate change and climate variability. By appealing to the paleoclimatic record for analogies of a climate warmed through anthropogenic greenhouse gases| a discussion of potential climatic swings and regime changes is presented. The policy implications of this work are also addressed. (C) 1998 Elsevier Science Ltd. All rights reserved. 4592,1998,4,3,Global coupled simulations of climate change due to increased atmospheric CO2 concentration,Two transient CO2 experiments using two coupled general circulation models developed by the French GASTON group have been realized using the same methodology. No flux corrections at the air-sea interface were used in these experiments. The main features of the present climate are reasonably well captured by both coupled models in the control simulations| although the biases are not the same. The transient CO2 simulations show a global warming| ranging between 1.6 and 2.0 degrees C at the time of CO2 doubling (+ 70 years). These values| and the main geographical characteristics of climate change| are in agreement with previous studies published by other research groups| using either flux corrected or non-flux corrected models. (C) Academie des sciences/Elsevier| Paris. 4513,1998,4,3,Global methane emission from wetlands and its sensitivity to climate change,The concentration of atmospheric methane (CH(4)) exerts a strong influence on atmospheric chemistry and the global climate. Natural and cultivated wetlands (rice paddies) are important sources of CH(4)| and the extent and strength of these sources may increase as a result of global warming and extension of rice production. Emission of methane From wetlands is an ecosystem process| closely coupled to local climatic and soil environments which influence complex processes of plant growth| soil organic matter decomposition| methanogenesis and CH(4) oxidation. Rates of emission show large variation in both space and time and their estimation from point measurements or from correlation with net primary production is difficult and unreliable. Here we report a study in which process-based ecosystem models were used to estimate global CH(4) emissions from natural wetlands and rice paddies| and the sensitivity of the models to simple climate change scenarios were tested. Our estimate of global emission was 145 Tg yr(-1)| of which 92 Tg yr(-1) came from natural wetlands and 53 Tg yr(-1) from rice paddies. The emissions from wetlands at high-latitude and rice paddies were only half of those reported in the traditional literature| confirming more recent measurements. The models also showed thar modest global warming may produce a higher CH(4) emission| but that this effect may be reversed by larger increases in temperature| due to the effect of soil moisture depletion. (C) 1998 Elsevier Science Ltd. All rights reserved. 4549,1998,4,4,Global warming and geothermal profiles: The surface rock-temperature response in South Africa,Southern hemisphere and South African regional air temperature anomalies for the period 1860-1996 are compared to borehole-derived surface rock-temperature anomalies to assess the extent to which surface rock temperatures reflect possible global warming in South Africa. The warming of the southern hemisphere since the mid-nineteenth century is evident in the regional air temperatures for South Africa. Following a temperature increase to a maximum in the 1920s| the climate cooled until strong warning recommenced in the mid 1970s. Highest temperatures have been experienced in the 1990s. Borehole-derived surface rock temperatures followed a similar pattern| but with a lag of a few decades in the case of the 1920s maximum. The overall warming trend is clearly evident in the rock temperatures. Despite uncertainties in the different data sets| an encouraging degree of agreement exists between the increase in rock temperatures during the twentieth century the corresponding regional South African air temperature increase and the southern hemisphere counterpart. 4661,1998,3,3,Global warming and sustainable energy supply with CANDU nuclear power systems,The United Nation's Intergovernmental Panel on Climate Change(IPCC) review of global warming issues suggests man's activities have resulted in a discemible influence on global climate. The panel identifies options which could be employed to ameliorate the climate influencing greenhouse effect which is attributed primarily to carbon dioxide and other gaseous emissions from fossil fuel energy sources. One option identified is nuclear power| as an alternative energy source which would reduce these emissions. The panel observes that| although nuclear power is a relatively greenhouse gas free energy source| there are a number of issues related to it's use which are slowing it's deployment. This paper enumerates the issues raised by the IPCC and addresses each in turn in the context of CANDU reactors and sustainable development. It is concluded that the issues are not fundamental barriers to expanded installation of nuclear fission energy systems. Nuclear reactors| and CANDU reactors in particular| can meet the energy needs of current generations while enhancing the technological base which will allow future generations to meet their energy needs. The essential requirements of a sustainable system are thus met. (C) 1997 Published by Elsevier Science Ltd. 4672,1998,2,4,Global warming and the future of Caribbean coral reefs,Computer simulations with the COREEF model (Graus et al. 1984) demonstrate that the growth of Caribbean coral reefs will be unable to match all but the most optimistic predicted rates of sea level rise that global warming is expected to cause over the next few centuries| and| therefore| these reefs will gradually become more submerged. As they deepen| higher waves will propagate into back-reef areas| altering the ecological and sedimentological zonation patterns and accelerating the erosion of leeward shelves and shores. Resuspended sediment will increase the turbidity| causing the demise of sediment-sensitive corals and possibly entire reef communities. 4579,1998,4,4,Global warming deduced from MSU,Microwave Sounding Unit (MSU) radiometer observations in Channel 2 (53.74 GHz) made from sequential| sun-synchronous| polar-orbiting NOAA operational satellites have been used to derive global temperature trend for the period 1980 to 1996. Christy et al. (1998) emphasize that they find a tropospheric cooling trend (-0.046 K decade(-1)) from 1979 to 1997 with these MSU data| although their analysis of near nadir measurements yields a near zero trend (0.003 K decade(-1)). Using an independent method to analyze the MSU Ch 2 nadir data separately over global ocean and land| we infer that the temperature trends over both these regions are about 0.11 K decade(-1)| during the period 1980 to 1996. This result is in better agreement with trend analyses based on conventional surface data. 4534,1998,3,2,Global warming implications of replacing ozone-depleting refrigerants,Under the provisions established in the Montreal Protocol| many of the chlorofluorocarbon and hydrochlorofluorocarbon compounds that have grown popular as refrigerants must be phased out due to their ozone-depleting potentials. At the same time| governments around the globe are beginning to confront problems of anthropogenic global warming. Energy usage is one of the primary sources of the carbon dioxide emissions known to cause global warming. As a result| heating| ventilating| and air conditioning systems must be made more efficient. An overview is presented of the global warming implications of ongoing movements toward the replacement of ozone-depleting refrigerants. Potential refrigerants are evaluated with the total equivalent warming impact measure.
4668,1998,4,2,Global warming needs action says UK chief scientific adviser| Sir Robert May,In a paper published on 30 September 1997| based on work by the UN Intergovernmental Panel on Climate Change (IPCC)| Sir Robert May| the Government's Chief Scientific Adviser| emphasises their view that humans are having a discernible effect on climate change. "On current trends| carbon dioxide will be present in the atmosphere at twice pre-industrial levels by around the middle of the next century|" said Sir Robert. "The IPCC predicts that such an increase would lead to an average global temperature increase of between 1.5 and 4.5C| most probable 2.5C. This may sound trivial but the estimated range of variability in global temperature over the past 1|000 years is around 1C."
4566,1998,3,4,Global warming: Least-cost electricity planning to meet CO2 emissions limits,This paper explores least-cost strategies for reducing CO2 emissions from the electric power industry. It uses an economic-engineering model for electric generation capacity expansion to investigate expansion plans which meet alternative CO2 emissions constraints in the lowest cost. The model selects the mix of various energy technologies| which are either presently in use or will possibly be in use in the future| to meet a specific carbon emissions limit and| furthermore| estimates the optimal tax required to achieve the least-cost strategy for reducing emissions to the desired level. Using Greece as a case study| the study suggests that to stabilize CO2 emissions at their 1990 level by the year 2005 and thereafter| the industry should move away from lignite generation to hydro and renewables and to coal or lignite technologies with CO2 removal capabilities. An optimal tax of $105 per toll of carbon is required to achieve this target in the lowest cost. (C) 1998 John Wiley & Sons| Ltd. 4611,1998,4,5,Global warming: Science or politics| Part 1 - Which observations are correct?,The balance of evidence suggests that there has been a discernible influence of human activity on global climate is a statement employed as the foundation basis to intervene on behalf of the globe and the future. That statement| as scientific evidence of human-produced greenhouse gases (primarily CO2) having a warming effect on global climate is a political statement only. Further| the Kyoto conference to consider intervention in human activities regarding global warming was a political conference. Political and treaty issues were the focus; scientific issues were not much discussed. What change is needed then to scientifically determine global warming and to ascertain whether human activity is involved? A better understanding of the natural climate variations related to solar variation can improve understanding of an anthropogenic greenhouse effect on the climate. The purpose of this article is to pose the scientific question.
4600,1998,4,4,Global warming: Science or politics? Part 2,Part II. Examines the scientific and political issues concerning the predicted dire consequences of global warning. Natural resources consumption; Energy resources; Environmental fate; Flawed assumptions and modeling of global systems; Aspects of the United Nations Framework Convention on Climate Change (UNFCC); Implications for the United States citizens and the economy; Need for intervention.
Whatever objections may be raised| it is clear that the issues of global warming and greenhouse gas emissions are not going to go away. Powerful lobbies on both sides of the argument will ensure that the debate continues| but pressures on governments and individual companies to act (and to be seen to be acting) are likely to grow rather than diminish| Financial incentives for "green" processes are also likely to increase| In this contest| the production of ethanol from sugar| as pioneered on large scale by Brazil| could give major economic and political benefits| above and beyond the ecological considerations which are the main subject of the following report.
4665,1998,4,3,Growth of fluoroform (CHF3| HFC-23) in the background atmosphere,There is growing concern over the emission and accumulation of very long-lived fluorinated trace gases in the atmosphere| due to their large global warming potentials (GWPs). Unlike CFCs and other ozone-depleting| chlorinated and brominated chemicals| consumption of these fluorinated compounds is not controlled by the Montreal Protocol or any other international agreement. Of all the known and potential trace 'greenhouse' gases| the two with the highest GWPs are sulfur hexafluoride (SF6) and fluoroform (CHF3| HFC-23). Whereas several studies have reported the detection and accumulation of SF6 in the atmosphere| the presence of HFC-23 has remained unreported. We have found that present-day HFC-23 concentrations (c. 11 pptv in late 1995) exceed those of SF6 by a factor of three. Concentrations have steadily increased in the atmosphere since at least 1978| and are continuing to do so at a present rate of 5% per year. Furthermore| HFC-23 appears to be long-lived in the atmosphere| with a stratospheric lifetime of at least 1000 years| and a modelled tropospheric lifetime of 230 years. In terms of global warming| the cumulative emissions of HFC-23 up to| and including| 1995 are equivalent to 1.6 billion tonnes of CO2. 4555,1998,3,4,Heat transfer from supercritical carbon dioxide in tube flow: A critical review,Since the discovery that CFCs and HCFCs destroy the ozone layer and cause global warming| the need to regulate their use has been critical. In the ensuing search for new environmentally benign refrigerants| carbon dioxide has been considered due to its excellent thermophysical properties. This paper gives a review of the heat transfer and pressure drop characteristics of supercritical carbon dioxide in tube flow. This information is necessary for designing the gas cooler of a carbon dioxide refrigeration system. A comparison of the different heat transfer correlations applicable to cooling of supercritical carbon dioxide has also been made. 4595,1998,2,3,Heavy precipitation processes in a warmer climate,Climate simulations have suggested that a greenhouse-gas induced global warming would also lead to a moistening of the atmosphere and an intensification of the mean hydrological cycle. Here we study possible attendant effects upon the frequency of heavy precipitation events. For this purpose simulations with a regional climate model are conducted| driven by observed and modified lateral boundary conditions and sea-surface temperature distributions. The modifications correspond to a uniform 2K temperature increase and an attendant 15% increase of the specific humidity (unchanged relative humidity). This strategy allows to isolate the effects of an increased atmospheric moisture content from changes in the atmospheric circulation. The numerical experiments| carried out over Europe and for the fall season| indicate a substantial shift towards more frequent events of strong precipitation. The magnitude of the response increases with the intensity of the event and reaches several 10s of percent for events exceeding 30 mm per day. These results appear to apply to all precipitation events dominated by sea-to-land moisture transport. 4596,1998,4,4,Height variations and secular changes in sea level,The problem of understanding| assessing and quantifying the causes of sea-level changes has received increased attention during the past several years| in particular in connection with predictions regarding a rise in the global mean se:a level due to global warming. The impact aspect of sea-level rise is of particular concern for many coastal areas in densely populated regions of the world. The present availability of space geodetic techniques providing high-accuracy measurements of station positions and of their time variations makes it possible to separate vertical crustal movements and absolute sea-level fluctuations. Gravimetric methods play an important role in the assessment of sea-level variations by providing completely independent measurements of vertical crustal movements. Satellite altimetry now enables the measurement of the spatial variability of sea level| Geological observations can infer former sea levels which are important to understand the present trends. This paper addresses the study of height variations and secular changes in sea level by discussing the most interesting questions and issues| by presenting the current understanding of the phenomena involved| and finally by illustrating the measuring and modeling techniques to be adopted for a comprehensive approach to the problem. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. 4623,1998,3,4,HFC-245fa as a blowing agent for water heater foam insulation,The North American water heater market has eliminated the use of the chlorofluorocarbon blowing agent CFC-11 in polyurethane insulation systems. Today the water heater market primarily uses the hydrochlorofluorocarbon blowing agent HCFC-141b. However| as a result of the Montreal Protocol| HCFC-141b is a transitional blowing agent| and must be replaced with "third generation" blowing agents by 2003. The next generation of blowing agents must have zero ozone depletion potential (ODP) and low global warming potential (GWP). Additionally for the water heater market| the blowing agent must produce foams with low thermal conductivity. Water heaters must conform to energy requirements established by the Department of Energy. Future legislation is expected to impose stricter requirements on the energy efficiency of water heaters. In addition to low thermal conductivity| there are other desirable features of a blowing agent for water heater insulation systems. The blowing agent should be a liquid at room temperature| with a boiling point similar to those of CFC-11 and HCFC-141b. The blowing agent should be miscible with many differentpolyols and processable in existing foam equipment. It should be non-flammable and nan-toxic. It should be reasonably priced and readily available. HFC-245fa has been identified as a primary candidate for a liquid| zero ODP blowing agent. The objective of this work was an evaluation of HFC-245fa in water heater insulation systems. Water heater foam systems using HFC-245fa were evaluated for stability| processability| physical properties| and energy performance. Results of these studies were compared to HFC-141b water heater foam systems. 4535,1998,4,4,High-pressure vapor-liquid and solid-gas equilibria using a Peng-Robinson group contribution method,In this paper| the new excess Gibbs energy mixing rule| which coupled with the consistent form with the quadratic composition dependence of the second virial coefficient and the excess Gibbs energy (G(0)(E)) at standard zero pressure| has been developed. This proposed mixing rule| combining a Peng-Robinson equation of state with the analytical solutions of groups (ASOG) group contribution method| provide a Peng-Robinson group contribution method (PRASOG). The PRASOG model has predicted the high-pressure vapor-liquid equilibria (VLE) for binary systems containing alcohols| acetone| and water using the available ASOG group pair parameters determined at low pressure with good accuracy. The ASOG parameters have also been shown for 31 group pairs relating to two gas groups| CO2 and CH4| which indicate potential for global warming| using binary experimental high-pressure VLE data in the temperature range 200-600 K. High-pressure VLE have then been correlated for 56 binary systems containing carbon dioxide and/or methane. These results are compared with those of the predicted Soave-Redlich-Kwong (PSRK) and linear combination of the Vidal and Michelsen (LCVM) models. Finally| using the group pair parameters that have been determined from VLE data| solid-gas equilibria have been predicted with fairly good accuracy for eight binary and one ternary systems containing carbon dioxide. 2310,1998,2,4,How environmental conditions affect canopy leaf-level photosynthesis in four deciduous tree species,Species composition of temperate forests vary with successional age (i.e.| years after a major disturbance) and seems likely to change in response to significant global climate change. Because photosynthesis rates in co-occurring tree species can differ in their sensitivity to environmental conditions| these changes in species composition are likely to alter the carbon dynamics of temperate forests. To help improve our understanding of such atmosphere-biosphere interactions| we explored changes in leaf-level photosynthesis in a 60-70 yr old temperate mixed-deciduous forest in Petersham| Massachusetts (USA). Diurnally and seasonally varying environmental conditions differentially influenced. in situ leaf-level photosynthesis rates in the canopies of four mature temperate deciduous tree species: red oak (Quercus rubra)| red maple (Acer rubrum)| white birch (Betula papyrifera)| and yellow birch (Betula alleghaniensis). We measured in situ photosynthesis at two heights within the canopies (top of the canopy at similar to 20 m| and in the sub-canopy of the same individual trees at similar to 14-16 m) through a diurnal time course on 7 d over two growing seasons. We simultaneously measured a suite of environmental conditions surrounding the leaf at the time of each measurement. We used path analysis to examine the influence of environmental factors on insitu photosynthesis in the tree canopies. Overall| red oak had the highest photosynthesis rates| followed by white birch| yellow birch| and red maple. There was little evidence for a substantial midday depression in photosynthesis. Instead| photosynthesis declined throughout the day| particularly after 1600. Diurnal patterns of light reaching canopy leaves| leaf and air temperature| and Vapor pressure deficit (VPD) contributed to diurnally varying photosynthesis rates. Large differences in these parameters through the growing season partly led to the seasonal differences observed in photosynthesis rates. Path analyses helped to identify the relative contribution of various environmental factors on photosynthesis and further revealed that species-specific sensitivities to various environmental conditions shifted through the season. Red oak photosynthesis was particularly sensitive to air temperatures late in the season when air temperatures were low. Further| red maple photosynthesis was particularly sensitive to high VPDs through the growing season. Incorporating data on the physiological differences among tree species into forest carbon models will greatly improve our ability to predict alterations to the forest carbon budgets under various environmental scenarios such as global climate change| or with differing species composition. 4615,1998,2,4,Impact of global warming on the distribution and survival of the gelada baboon: a modelling approach,The gelada baboon is a graminivorous primate whose ecology is unusually sensitive to ambient temperature. A systems model of the socio-ecology of the gelada is used to predict the impact of global warming on the species' altitudinal distribution. The species' lower altitudinal limit will rise by approximate to 500 m for every 2 degrees C increase in global mean temperature. A 7 degrees C rise in temperature would be sufficient to result in the species being confined to a small number of isolated mountain peaks| where its chances of survival will be greatly reduced. Changes in local climate are also likely to have significant effects on agricultural practice on the Ethiopian highlands| and this in turn is likely to have repercussions for the distribution patterns of the gelada by further constraining the habitat available to them. 2322,1998,2,4,Implications of global climate change for tourism and recreation in wetland areas,Tourism and recreation are important economic activities which are major agents of change globally and| more specifically| in wetland areas. There is a regular round of activities associated with the seasons and anything which influences operating seasons is likely to have substantial consequences for tourism businesses. Atmospheric conditions influence both whether or not people will participate as well as the quality of the experience. In marine coasts| wetland recreations may be threatened by rising sea levels but recreation in inland water bodies may be affected more by deficiencies rather than superabundance of water. Marinas and recreational boating are harmed by extremes of both high and low water| particularly the latter which is the most likely situation under global climate change. Two main groups can be considered with respect to the potential to adapt to climate change. These are the participants themselves and the businesses which cater to them. It is argued that the former are likely to be much more adaptable than the latter. 2359,1998,2,4,Implications of harmful microalgae and heterotrophic dinoflagellates in management of sustainable marine fisheries,Worldwide increases in the frequency and spatial extent of blooms of harmful marine microalgae and heterotrophic dinoflagellates suggest that these species are becoming an increasingly important influence on year class strength of marine fishes through both direct and indirect mechanisms. Impacts on fish populations from harmful marine microalgae and heterotrophic dinoflagellates have been considered primarily from the limited view of acute or lethal influences. Accumulating evidence indicates that insidious sublethal and chronic impacts to both fish and human health from these organisms| such as long-term behavior alteration| increased susceptibility to cancers and other diseases| depressed feeding| and impaired reproduction| may be substantial and pervasive. For some harmful species| significant indirect impacts that promote critical habitat loss or disrupt the microbial food web balance also have been documented. Because successful models to predict the behavior and growth of most of these species have not yet been developed| and because toxins for many are poorly characterized| a clear anthropocentric focus has guided management strategies for confronting their outbreaks. The extent to which management takes the fundamental step of acknowledging scientifically demonstrated linkages among harmful microalgae| shellfish contamination| fish kills| and human health impacts has also been seriously constrained by political dictates stemming from economic considerations. Without federal involvement| and without catastrophe of human death or widescale serious human illness| little progress historically has been realized in the development of effective management strategies to mitigate lethal impacts to fish or other organisms. Many long-known taxa such as certain "red tide" dinoflagellates apparently can increase independently of human influences other than physical transport. However| some newly discovered toxic or otherwise harmful taxa have been correlated with cultural eutrophication in poorly flushed fish nursery grounds such as estuaries and coastal waters. Outbreaks of certain warm-optimal species have coincided with El Nino events| suggesting that warming trends in global climate change may stimulate their growth and extend or shift their range. The available information points to a critical need for a more proactive| concerted effort to determine the full range of chronic/sublethal effects| as well as acute impacts| on marine fish populations by harmful marine microalgae and heterotrophic dinoflagellates| so that their increasingly important influence can be factored into reliable plans for sustainable fisheries management.
4678,1998,3,2,Importance of nuclear generation in the struggles to reduce CO2 emission at Kansai Electric Power Co,It has been pointed out in recent years that the potential impacts of global warming has been becoming more and more serious because of the rapid increase of anthropogenic CO2 emission. Japan's annual CO2 emissions (fiscal 1994) amounted to 343 million tons of carbon. Although CO2 emissions caused by fossil-fuel power generation accounted for 29.4% of total| on a sector basis| those directly from the energy conversion sector accounted for only 7.7%| Most CO2 emissions (21.7% of total) resulted from electric power use in the industrial| commercial and domestic sectors. Thus| the reduction of CO2 emissions caused by the use of electricity is a nationwide subject| Understanding that both supply side and demand side approaches are necessary| Kansai Electric has been deploying "New ERA Strategy" as a comprehensive strategy to seek a potential for CO2 reduction mole broadly and deeply. Among a number of action items are the promotion of nuclear power generation| and improvement of overall energy efficiency besides such demand side measures as leveling off the peak load. The effectiveness of action items of the New ERA Strategy was evaluated in terms of CO2 reduction. As a result| estimated CO2 reduction related to nuclear power amounted to 88% of the total for fiscal 1995 in comparison with 1990| and that expected in 2000 is 84%| These results reconfirm that nuclear power is always the key to practical CO2 reduction at present and in the future. Comparison with candidate technology alternatives revealed that photovoltaic power generation needed 7 times greater rated capacity and 280 times larger area than nuclear power| so it is not realistic as a central power station alternative. The comparison also clarified that if wind power stations were constructed at all feasible sites in the Kansai region| they would not be a viable alternative to a single nuclear unit from CO2 duction viewpoint. (C) 1997 Published by Elsevier Science Ltd. 2334,1998,2,4,Individualistic species responses invalidate simple physiological models of community dynamics under global environmental change,1. Most predictions of species distribution and abundance changes in response to global warming relate the individual requirements of a single isolated species to climate variables through some form of climate mapping. This method fails to account for the effects of species dispersal and species interactions| both of which may strongly affect distribution and abundance. 2. We therefore examined the effects of dispersal and species interactions on the distribution and abundance of three Drosophila species in a laboratory system that mimicked a latitudinal dine of 15 degrees C. We then investigated how species distribution and abundance in this system responded to simulated global warming. 3. Dispersal allowed populations to persist at non-optimum temperatures| overriding physiologically imposed range limits. 4. Temperature determined the outcome of competition. In pairwise interactions| Drosophila subobscura eliminated D. melanogaster or D| simulans at low temperatures but was itself eliminated at high temperatures. 5. Competitive interactions changed abundance and range sizes thus shifting the position of species optima. These changes depended on both the number and the identity of the competing species. 6. Enemy-victim interactions altered range and abundance. Adding the parasitoid Leptopilina boulardi affected the host assemblage directly at high temperatures where the parasitoid was present| and indirectly (mediated by dispersal) at low temperatures where it was scarce or absent. Host species coexisted for longer at low temperatures in dines when parasitoids were present than when they were absent. 7. Simulated global warming produced complex| counter-intuitive effects on distribution and abundance| including the reversal of species' relative abundance at some temperatures. 8. Because dispersal and species interactions strongly influenced both range and abundance (sometimes in unexpected ways) current species distributions are no guide to what they might be under global climate change. Furthermore| since both these factors are missing from climate envelope models of range and abundance change| their predictions are| at best| incomplete. 4633,1998,2,4,Influences of climatic change on some ecological processes of an insect outbreak system in Canada's boreal forests and the implications for biodiversity,Insect outbreaks are a major disturbance factor in Canadian forests. If global warming occurs| the disturbance patterns caused by insects may change substantially| especially for those insects whose distributions depend largely on climate. In addition| the likelihood of wildfire often increases after insect attack| so the unpredictability of future insect disturbance patterns adds to the general uncertainty of fire regimes. The rates of processes fundamental to energy| nutrient| and biogeochemical cycling are also affected by insect disturbance| and through these effects| potential changes in disturbance patterns indirectly influence biodiversity. A process-level perspective is advanced to describe how the major insect outbreak system in Canadian forests| that of the spruce budworm (Choristoneura fumiferana Clem. [Lepidoptera: Tortricidae])| might react to global warming. The resulting scenarios highlight the possible importance of natural selection| extreme weather| phenological relationships| complex feedbacks| historical conditions| and threshold behavior. That global warming already seems to be affecting the lifecycles of some insects points to the timeliness of this discussion. Some implications of this process-level perspective for managing the effects of global warming on biodiversity are discussed. The value of process-level understanding and high-resolution| long-term monitoring in attacking such problems is emphasized. It is argued that a species-level| preservationist approach may have unwanted side-effects| be cost-ineffective| and ecologically unsustainable. 4481,1998,2,4,Influences of large-scale climatic variability on episodic tree mortality in northern Patagonia,In the context of potential-global warming| it is critical that ecologists bridge the typically local spatial scale of ecology to the regional scale of climatology by linking ecosystem responses to variations in the large-scale synoptic controls of regional climates. In northern Patagonia| Argentina| we related regional-scale tree mortality events over the past similar to 100 years to annual and decadal-scale climatic variations associated with changes in the major synoptic climatic controls of the southeastern Pacific region| including the El Ni (n) over tilde o-Southern Oscillation (ENSO). In nine stands of Austrocedrus chilensis| a xeric conifer| we used dendrochronological techniques to date the outermost tree ring on dead-standing and fallen trees to estimate the dates of tree death for 336 trees. To evaluate climatic conditions during periods of high tree mortality| we used regional records of precipitation and temperature from six climate stations and also used a regional set of 24 tree ring chronologies from Austrocedrus. Good preservation of the resinous wood of Austrocedrus allowed relatively precise dating of tree deaths over the past similar to 90 years. Episodes of massive tree mortality coincide with exceptionally dry springs and summers during the 1910s| 1942-1943| and the; 1950s. Although there is a general regional synchroneity of tree death associated with drought| intra-regional variations in the intensity of droughts| as interpolated and mapped from the regional network of tree ring chronologies| are also reflected by north-to-south variations in tree mortality patterns. Periods of drought and associated tree mortality during the 20th century in northern Patagonia are strongly associated with above average sea level atmospheric pressure off the coast of Chile at the same latitudes. Temperature and precipitation in northern Patagonia are highly influenced by the intensity and latitudinal position of the southeastern Pacific anticyclone| which| in turn| are greatly affected by ENSO. Tree mortality in northern Patagonia appears to be intensified by extreme events of the Southern Oscillation and is more strongly coincident with El Ni (n) over tilde o events along the coast of northern Peru. These results| in combination with previously established climatic influences on fire occurrence and tree seedling establishment| strongly link stand-level and regional-scale forest dynamic processes in northern Patagonia with variations in large-scale atmospheric conditions. 4545,1998,3,4,Integrated infrared absorption coefficients of several partially fluorinated ether compounds: CF3OCF2H| CF2HOCF2H| CH3OCF2CF2H| CH3OCF2CFClH| CH3CH2OCF2CF2H| CF3CH2OCF2CF2H AND CH2=CHCH2OCF2CF2H,The integrated absorption coefficients of CF3OCF2H| CF1HOCF2H| CH3OCF2CF2H| CH3OCF2CFClH| CH3CH2OCF2CF2H| CF3CH2OCF2CF2H and CH2 = CHCH2OCF2CF2H have been measured at 298 K for use in calculations of their global warming potentials. The results for the ethers were compared to the integrated absorption coefficients of a standard compound| CCl3F. To assess the potential impact of the ethers on terrestrial infrared radiation| the absorption coefficients were both weighted by the Plank function and also used in the simple method of estimating the instantaneous radiative forcing given in Pinnock et al. (C) 1998 Elsevier Science Ltd. All rights reserved. 4532,1998,3,4,Investigation of CF3I as an environmentally benign dielectric etchant,In this study| trifluoroiodomethane (CF3I)| a non-global-warming gas| has been investigated as a substitute for typical PFC's currently used in wafer patterning and CVD chamber cleaning processes. Dielectric films consisting of plasma enhanced chemically vapor deposited silicon dioxide and silicon nitride were comparatively etched in CF3I and C2F6/O-2 plasma environments. The etch rate of these films was ascertained as a function of applied rf power| etchant gas flow rate| reaction chamber pressure| and CF3I:O-2 ratio. Destruction efficiencies of CF3I at different processing parameters were evaluated. Depending on the flow rate| rf power| and chamber pressure| utilization efficiency of CF3I varied from as low as 10% to as high as 68%. CF4| C2F6| COF2| and CO2 were the predominant by-products found in the exhaust stream; however| their concentrations were very low compared to the traditional process employing C2F6/O-2 mixtures. 4509,1998,3,3,Isolation of acidophilic methane-oxidizing bacteria from northern peat wetlands,Acidic northern wetlands are an important source of methane| one of the gases that contributes to global warming. Methane oxidation in the surface of these acidic wetlands can reduce the methane flux to the atmosphere up to 90 percent. Here the isolation of three methanotrophic microorganisms from three boreal forest sites is reported. They are moderately acidophilic organisms and have a soluble methane monooxygenase| In contrast to the known groups of methanotrophs| 16S ribosomal DNA sequence analysis shows that they are affiliated with the acidophilic heterotrophic bacterium Beijerinckia indica subsp. indica. 4531,1998,3,3,Italian policies for the diffusion of renewable energies to fight global warming,The necessity to find correct answers to the climate change issue represents the driving force that is increasing the potential role of the renewable sources in Italy as in most industrialised countries. A quantity between a forth and a fifth of the reduction of greenhouse gases necessary in Italy to comply with the Kyoto protocol could be derived from renewable sources.
4632,1998,3,4,Japanese automotive transportation sector's impact upon global warming,Automobiles are still increasing in number in Japan. If this continues| CO2 emissions in this sector may increase through the first half of the 21st century. Consequently| a study of measures for reducing these CO2 emissions is essential. In this paper| possible automotive technologies| improvements in fuel consumption and the introduction of electric vehicles are discussed. These measures are then evaluated for the Japanese case. Furthermore| market penetration of these technologies is evaluated| using life-cycle cost analysis based on initial cost and annual fuel cost. It is concluded that reducing CO2 emissions to 1995 levels by 2010 is possible. This would require the simultaneous implementation of fuel-consumption improvements and the introduction of electric vehicles. However| automotive consumers would be reluctant to accept these technologies| particularly electric vehicles| because of their high purchase-price and low benefits in terms of operating economy. Acceptance will require financial and institutional support from the public sector in introducing these automotive technologies into the Japanese transportation sector. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. 4493,1998,2,4,Kernel abnormalities in malting barley - determining terminology and assessment,Kernel abnormalities are favourably influenced by extreme weather conditions in the corn ripening phase. Frequent occurence of such phenomena has to be taken into consideration should there be a change in climate in central Europe due global warming. Abnormalities of kernels can inhibit the utilization of malting barley. Because of the varying importance in malting and brewing technology| each phenomena must be clearly separated from one another. Differences are made between grain with split kernels| incomplete overlapping of husks| damaged husks| second tillering and pre-harvest sprouting. As well as the environmental effects| genetic variability also becomes apparent which is valuable for the determination of plant breeding and variety selection. influences of technical production can significantly increase or even reduce the risk but are relatively insignificant when compared with the overall variability. The breeding of early ripening varieties should be encouraged| not only because of its relation to second tillering. Examination conditions in barley breeding and variety authorisation should be modified to favour early ripening varieties. 2363,1998,3,3,Key elements related to the emissions trading for the Kyoto protocol,The emissions trading first proposed by the US as a concrete idea is a promising policy framework to tackle the global climate change issue. It not only has its high cost efficiency/flexibility but also has big potential as an instrument which is profitable for both buyers and sellers and (must) enforce(s) the compliance with the emission limitations| in principle. It can be the incentives for economy in transition Parties to choose energy-saving economic development path and also for the developing country Parties to join the regime in the following phases. This paper focuses on its pragmatic aspects and clarifies its merits and problems to be solved in order to probe into its possibilities to be installed. Some related trading scheme on environmental issues are discussed to have implications for the climate change case. For climate change trading scheme| concrete proposals are suggested for the emissions budget approach and borrowing. In addition| an idea - packaging carbon taxation and emissions trading - is proposed for the establishment of the domestic emissions market which guarantees the compliance of the Protocol automatically. These elements and proposals are expected to be useful information to clarify the points for the international negotiations with some concrete images| not general ideas. (C) 1995 Elsevier Science Ltd. All rights reserved. 4506,1998,3,3,Large scale carbon dioxide production from coal-fired power stations for enhanced oil recovery: A new economic feasibility study,Enhanced oil recovery (EOR) technologies must be increasingly applied in order to sustain the current production capacity of conventional oil in Western Canada. Among these technologies| carbon dioxide (CO2) flooding is a highly attractive possibility. At the same time| a large amount of CO2 is being produced by coal-fired power plants in this region. The CO2 is currently discharged into the atmosphere and could be a major contributor to the so-called greenhouse effect| which would lead to global warming. Thus| the concept of capturing CO2 and utilizing it as a flooding agent in EOR processes is currently generating much interest among oil| utility and coal companies. This paper describes how cogeneration concepts| together with process optimization strategies| help to reduce the CO2 production cost by utilizing low-pressure steam and waste heat from various sections of the power generation process. Based on these concepts and strategies| results from this study show that the recovery cost of CO2 from a coal-fired power plant can range between $0.50 - 2.00/mscf. If the cost is approximately $1.25/mscf| the production cost of a barrel of incremental oil would be less than $18. Therefore| at modest oil prices| there is room for profit to be made operating a CO2 flood with flue gas extracted CO2. The technical and economic feasibility of the concepts are evaluated and practical implications for the Saskatchewan resources are discussed. 4521,1998,2,4,Large-scale deforestation for plantation agriculture in the hill country of Sri Lanka and its impacts,The forest cover in the hill country river catchment areas of Sri Lanka has been reduced to isolated patches on hilltops and a handful of reserves above the 1524 m (5000 ft) contour. Most of the land that was under forest cover at the turn of the nineteenth century is now covered with plantation crops. The districts of Kandy| Matale| Nuwara Eliya| Badulla| Ratnapura and Kegalle are the main hill country plantation areas. Within a period of less than half a century most of the forests in the hill country were cleared for plantation crops. Shifting cultivation was responsible for deforestation in the drier parts of the hill country. At the time of the British conquest of the hill country| the population of the whole island was not more than 3/4 to 1 million and they had settled in isolated villages at elevations below 1066 m. Subsistence agriculture was the main occupation of this predominantly rural population. During the first phase (1830-1880) of the plantation industry| large tracts of mostly forest land were cleared for coffee cultivation. By 1878| the extent of the coffee plantations reached its maximum of 111 336 ha most of which was situated in the wet zone hill country. The second phase of plantation agriculture began as the coffee industry was completely wiped out by a leaf disease. Most of the abandoned coffee plantations and the remaining forests were converted to tea| rubber and cinchona estates. The first two crops managed to survive price fluctuations in the world market| while the latter collapsed because of over production. During the period of large-scale deforestation in the hill country| the climate also underwent changes as exemplified by rainfall and temperature trends. However| these trends are not uniform everywhere in the plantation areas of the hill country. The temperature has risen a few degrees over a period of about a century and quarter in the hill country stations| while rainfall has declined significantly at some stations. These changes seem to be a result of the interaction of both global and local factors. Although some of these changes would have been a result of global warming| land use change would also have contributed to regional disparities. (C) 1998 John Wiley & Sons| Ltd. 4680,1998,3,4,Lean burn natural gas engines as a possible power unit in urban fleets of heavy duty vehicles with low environmental impact,This work aimed to examine the possibility of creating natural gas urban bus fleets by applying lean burn technology. Different engine configurations were tested| keeping in consideration the necessity to ensure suitable performance| and to meet the European regulations. With the target torque and power| the severe European limits| were not met only for methane emissions. In addition| the GWI (global warming impact) values were also computed and compared with proposed limits expressly conceived for natural gas engines. The results showed that the NG lean burn engine at the present state of development does not appear able to meet the future requirements of both low NOx emissions and GWI| because of the difficulty of resolving the trade-off between NOx and HC. 4494,1998,3,2,Life cycle inventory analysis of national electricity supply system,The environmental aspects of the electricity supply system in Korea has been analyzed from the point of view of Life Cycle Assessment (LCA). As an initial step| thermal power generation| which has the largest portion in national electricity system and is considered to release significant amounts of emissions| is defined as the system. All the inputs and outputs associated with the defined system has been identified and calculated based on the delivery of 1kWh electricity generated by thermal power to consumers. The national electricity supply system is a circle-network type connecting the whole country to a single super grid with all generators feeding into it and all consumers drawing from it. Thus| the national averaged data have been collected and used to describe the present system. The Life Cycle Inventory Analysis (LCI) results show that anthracite releases the largest amount of airborne emissions and LNG releases the smallest amount of emissions among the fuels used in thermal power generation. The most dominant airborne emission is CO(2) which is one of the main causes for global warming effect. Waterborne emissions like COD| SS| oil etc; and solid wastes such as waste synthetic resins and combustion ashes are also quantified. The results of the analysis carried out here will be a part of the basic database for indispensible electricity in LCA studies for almost all industries. 4495,1998,3,3,Lifetimes and global warming potentials for dimethyl ether and for fluorinated ethers: CH3OCF3 (E143a)| CHF2OCHF2 (E134)| CHF2OCF3 (E125),Using recent kinetic data| two-dimensional (2-D) chemical-transport modeling of the atmospheric lifetimes of dimethyl ether and fluorinated ethers CH3OCF3 (E143a)| CHF2OCHF2 (E134)| and CHF2OCF3 (E125) shows that E134 and E125 have substantially larger lifetimes than previously estimated. Dimethyl ether has a short atmospheric lifetime of 5.1 days and a relatively insignificant radiative forcing leading to a relatively low global warming potential. Increasing fluorination is accompanied by slower rates of reaction with hydroxyl radical and ultimately longer lifetimes. E143a| E134| and E125 were found to have lifetimes of 5.7| 29.7| and 165 years| respectively. In addition| our work uses ab initio methodology to determine IR absorption cross sections for each ether. Our study finds that E134 and E125 have significant infrared absorption and thus relatively high radiative forcing values. These two properties together yield global warming potentials for E134 and E125 of 5720 and 14|000| respectively| integrated over a 100 year period. 2329,1998,4,4,Long-term climate change and main commercial fish production in the Atlantic and Pacific,Main Atlantic and Pacific commercial species of the subtropic| subarctic and arctic zones - Atlantic and Pacific herring; Atlantic cod; European| South African| Peruvian| Japanese and Californian sardine; South African and Peruvian Anchovy; Pacific salmon; Alaska pollock; Chilean jack mackerel and some others - undergo long-term simultaneous oscillations. The total catch of these highly abundant species equals about 50 percent of the total Atlantic and Pacific marine fish harvest. The dynamics of northern hemispheric surface air temperature anomaly (dT) can hardly be correlated with long-term dynamics of marine commercial fish production because of high inter-annual variability. The so called atmospheric circulation index (ACI) characterizing a dominant direction of air mass transport was found to be closely related with long-term fluctuations of the main commercial stocks. This index has been registered over the Northern Hemisphere or more than 100 years using the Wangengeim-Girs method. Correlation coefficients between commercial catches and ACI dynamics in the period of 1900-1994| stayed in the range of 0.70-0.90. The global character of the ACI dynamics is confirmed by its close correlation with such global geophysical characteristics as the earth rotation velocity index (ERVI). Approximately 50-70 year simultaneous cycles were observed in stock dynamics of the main commercial species| ACI and ERVI. The dynamics of main commercial stocks in both Atlantic and Pacific follow the alternation of the so-called circulation epochs (meridional or 'latitudinal'). The long-term changes of dT| ACI| ERVI and commercial stock dynamics display the beginning of new climate-production phase similar to that of 1950-1970s. (C) 1998 Elsevier Science B.V. All rights reserved. 4654,1998,2,4,Long-term exposure to small temperature increase and sublethal ammonia in hard water acclimated rainbow trout: does acclimation occur?,Juvenile rainbow trout (Oncorhynchus mykiss; initially 2-5 g) were exposed for 90 days to either ambient water temperature (natural thermal regime) or to +2 degrees C superimposed above the ambient water temperature (simulated global warming scenario)| in the presence or absence of a nominal 70 mu M total ammonia (1290 mu g l(-1) ionized (NH4+)| 10 mu g l(-1) unionized (NH3) ammonia). The exposures were conducted in moderately hard de-chlorinated water from Lake Ontario ([Ca2+]=0.96+/-0.02 mM| [Na+]=0.55+/-0.01 mM| [Cl-]=0.737+/-0.004 mh?) on three occasions: over summer (temperature range| 13.0-21.0 degrees C; pH=7.57+/-0.26) and winter (temperature range| 3.5-7.0 degrees C; pH=7.46+/-0.02) without food limitation (satiation feeding)| and during summer (temperature range| 13.0-18.5 degrees C; pH=7.38+/-0.09) with food limitation (1% daily| or restricted ration). Lethal temperature| lethal ammonia (1.8 mM total ammonia; approximately 31 700 mu g l(-1) NH4+| 900 mu g l(-1) NH3)| and lethal temperature plus ammonia challenges were conducted after each 90-day exposure to determine whether or not chronic pre-exposure conferred any increased tolerance to elevated temperature or ammonia. In addition| acute sublethal ammonia challenges (1.0 mM total ammonia; approximately 17 800 mu g l(-1) NH4+| 200 mu g l(-1) NH3)| together with unidirectional Na+ flux measurements| were conducted after the two summer exposures to gain further insight into the effects of prior sublethal ammonia exposure on Na+ regulation| as influenced by ration. The juvenile trout on unlimited ration and exposed to a warming scenario of +2 degrees C exhibited a slight| but significant elevation in lethal temperatures in both summer and winter| but the effect was not observed in fish fed a restricted ration. A challenge to lethal temperature and ammonia in combination reduced the lethal temperature anywhere from 3-7 degrees C for fish from all treatments; pre-exposure to ammonia offered some protective effect. However| prior ammonia exposure did not prolong survival times (LT(50)s) during lethal ammonia challenge| and there was no evidence of acclimation to elevated external ammonia with respect to Na+ balance| These results suggest that juvenile trout are likely to adapt to a small temperature increase| such as could be associated with a global warming scenario| but their potential for doing so may be restricted by sublethal ammonia and by nutritional status. (C) 1998 Elsevier Science B.V. 4624,1998,4,4,Making mistakes when predicting shifts in species range in response to global warming,Many attempts to predict the biotic responses to climate change rely on the 'climate envelope' approach(1-3)| in which the current distribution of a species is mapped in climate-space and then| if the position of that climate-space changes| the distribution of the species is predicted to shift accordingly(4-6). The flaw in this approach is that distributions of species also reflect the influence of interactions with other species(7-10)| so predictions based on climate envelopes may be very misleading if the interactions between species are altered by climate change(11). An additional problem is that current distributions may be the result of sources and sinks(12)| in which species appear to thrive in places where they really persist only because individuals disperse into them from elsewhere(13|14). Here we use microcosm experiments on simple but realistic assemblages to show how misleading the climate envelope approach can be. We show that dispersal and interactions| which are important elements of population dynamics(15)| must be included in predictions of biotic responses to climate change. 4627,1998,2,4,Malaria epidemics on the Highlands of Madagascar and of East and South Africa.,The Highlands of Madagascar were malaria free until 1878| when a severe epidemic occurred| following the development of irrigated rice farming. Then| the disease became endemic. Between 1949 and 1962| malaria was "eradicated" on the Highlands by joint house spraying and chemoprophylaxis measures. The main vector An. funestus disappeared. In 1986-1988| a very severe epidemic with high lethality rate devastated the Highlands. It is now under control. Thanks to the data of a religious dispensary we could follow the evolution of malaria on the Highlands from 1971 to 1995. The number of cases begin to grow in 1975 when the surveillance was neglected. A second step was observed in 1979| when chemoprophylaxis/chemotherapy centres were closed. Then| the increase of malaria became exponential up to 1988. At the time the prevalence had became similar to that of 1948| before the eradication. The epidemic is not due to global warming because the temperature has been stable for the last 30 years. The malaria rise was due the cancellation of control measures. When control was reactivated| the epidemic ceased. In Swaziland Zimbabwe and South Africa| malaria epidemics were also due to control failure. In Uganda Highlands| above 1500 m malaria rise seems linked to the environmental changes| e.g. the cultures which replace papyrus swamp in the valley But malaria did not overcame the altitude of 1900 which it had already reached in 1960. Rainfall should also be considered as a key factor in the epidemics. In the Sahel West Africa| temperature increased from 0|5 degrees C to 01 degrees C degree in the last 25 years| but rainfall decreased from 30 %. As a result| one of the vector; Anopheles funestus disappeared and malaria prevalence dropped by 60 to 80 %. It is not acceptable to predict the future evolution of malaria in taking in account only one parameter : the temperature. The whole factors involved in the epidemiology should be taken into account The predictions based only on the temperature increase (global warming) can be totally wrong if the rainfall| for example decreases. 2366,1998,2,4,Malaria in the African highlands: past| present and future,Many of the first European settlers in Africa sought refuge from the heat and diseases of the plains by moving to the cool and salubrious highlands. Although many of the highlands were originally malaria free| there has been a progressive rise in the incidence of the disease over the last 50 years| largely as a consequence of agroforestry development| and it has been exacerbated by scarce health resources. In these areas of fringe transmission where the malaria pattern is unstable| epidemics may be precipitated by relatively subtle climatic changes. Since there is little immunity against the disease in these communities| outbreaks can be devastating| resulting in a substantial increase in morbidity and death among both children and adults. We present here the results obtained using a mathematical model designed to identify these epidemic-prone regions in the African highlands and the differences expected to occur as a result of projected global climate change. These highlands should be recognized as an area of special concern. We further recommend that a regional modelling approach should be adopted to assess the extent and severity of this problem and help improve disease surveillance and the quality of health care delivered in this unstable ecosystem. 2313,1998,2,4,Managing the nations water in a changing climate,Among the many concerns associated with global climate change| the potential effects on water resources are frequently cited as the most worrisome. In contrast| those who manage water resources do not rate climatic change among their top planning and operational concerns. The difference in these views can be associated with how water managers operate their systems and the types of stresses| and the operative time horizons| that affect the Nation's water resources infrastructure. Climate| or more precisely weather| is an important variable in the management of water resources at daily to monthly time scabs because water resources systems generally are operated on a daily basis. At decadal to centennial time scales| though| climate is much less important because (1) forecasts| particularly of regional precipitation| are extremely uncertain over such time periods| and (2) the magnitude of effects due to changes in climate on water resources is small relative to changes in other variables such as population| technology| economics| and environmental regulation. Thus| water management agencies find it difficult to justify changing design features or operating rules on the basis of simulated climatic change at the present time| especially given that reservoir-design criteria incorporate considerable buffering capacity for extreme meteorological and hydrological events. 2360,1998,4,4,Marine reserves are necessary but not sufficient for marine conservation,The intensity of human pressure on marine systems has led to a push for stronger marine conservation efforts. Recently| marine reserves have become one highly advocated form of marine conservation| and the number of newly designated reserves has increased dramatically. Reserves will be essential for conservation efforts because they can provide unique protection for critical areas| they can provide a spatial escape for intensely exploited species| and they can potentially act as buffers against some management miscalculations and unforeseen or unusual conditions. Reserve design and effectiveness can be dramatically improved by better use of existing scientific understanding. Reserves are insufficient protection alone| however| because they are not isolated from all critical impacts. Communities residing within marine reserves are strongly influenced by the highly variable conditions of the water masses that continuously flow through them. To a much greater degree than in terrestrial systems| the scales of fundamental processes| such as population replenishment| are often much larger than reserves can encompass. Further| they offer no protection from some important threats| such as contamination by chemicals. Therefore| without adequate protection of species and ecosystems outside reserves| effectiveness of reserves will be severely compromised. We outline conditions under which reserves are likely to be effective| provide some guidelines for increasing their conservation potential| and suggest some research priorities to fill critical information gaps. We strongly support vastly increasing the number and size of marine reserves; at that same time| strong conservation efforts outside reserves must complement this effort. To date| most reserve design and site selection have involved little scientific justification. They must begin to do so to increase the likelihood of attaining conservation objectives. 2353,1998,3,3,Meeting the energy and climate challenge for transportation in the United States,Mitigating global climate change will require a profound transformation of energy use sectors throughout the world and this challenge is particularly acute for the United States transportation sector. Market forces alone are unlikely to change transportation-energy technologies and infrastructures sufficiently to address the needs for an environmentally sustainable system. A set of policies for encouraging technological advances and promoting sustainable planning| operations| and pricing of transportation services was analysed for its effects on sector energy use and greenhouse gas (GHG) emissions. Baseline projections show US transport sector GHG emissions increasing over the 1990 level 28% by 2010 and 58% by 2030. The combined impacts of the policies analysed would be substantial emission reductions that grow over time| with GHG emissions returned to the 1990 level by 2010 and cut to 35% lower by 2030. Due to fuel savings from technology-based efficiency improvements| it was found that the economic benefits accruing from these reductions would outpace costs almost from the outset. (C) 1998 Elsevier Science Ltd. All rights reserved. 4604,1998,5,3,Metamorphic CO2 degassing from orogenic belts,Kerrick and Caldeira (1993| 1994a) concluded that metamorphic CO2 degassing in collisional orogens| and especially the Himalayan orogenic belt| could have been an important factor in enhancing paleoatmospheric CO2 levels and contributing to early Cenozoic global greenhouse warming [Kerrick| D.M.| Caldeira| K.| 1993. Paleoatmospheric consequences of CO2 released during early Cenozoic regional metamorphism in the Tethyan orogen. In: Touret| J.L.R.| Thompson| A.B. (Guest-Eds.)| Fluid-Rock Intel.action in the Deeper Continental Lithosphere. Chem. Geol. 108| 201-230.] [Kerrick| D.M.| Caldeira| K.| 1994a. Metamorphic CO2 degassing and early Cenozoic paleoclimate. GSA (Geol. Sec. Am.) Today 4| 57-65.]. However| our revised CO2 mass loss computations for regional metamorphism in the Himalaya-Karakoram belt incorporating recent geochronologic data and revised estimates of the proportion of carbonate source rocks indicate that metamorphic CO2 degassing from this orogen cannot explain Early Eocene warmth. Widespread pluton-induced hydrothermal flow occurred during the Eocene in the Cordilleran belt of western North America. Synmetamorphic intrusions| which are common in metamorphic belts| may cause significant regional fluid flow. To obtain a representative CO2 flux from such environments| we computed a CO2 flux of 1.5 x 10(12) mol km(-2) Ma(-1) from petrologic and geochemical studies of the Paleozoic plutonic-metamorphic belt in New England (northeastern United States). For the 2 X 10(6) km(2) area of Eocene metamorphism in the North American Cordillera| the CO2 fluxes derived from the New England metamorphic belt yield an area-integrated flux of similar to 3 x 10(18) mol Ma(-1). If a significant fi action of this CO2 entered the atmosphere| this degassing flux would alone account for Eocene greenhouse global warming. For the Ominica belt within the Cordilleran orogen| a volumetric estimate of the mass of carbonate veins indicates that the consumption of CO2 by precipitation of carbonate veins may not significantly decrease the amount of CO2 in fluids that convect to near-surface crustal levels. Compared to other Eocene metamorphic belts| the widespread hydrothermal activity in the North American Cordillera may have been the largest| and most climatically significant| source of metamorphic CO2 to the Eocene atmosphere. CO2 degassing by active metamorphism is most significant in extensional regimes of high heat flow. Extensional tectonism and hydrothermal activity in metamorphic belts may have substantially contributed to atmospheric CO2 content throughout the Phanerozoic. Examples include the Mesozoic circum-Pacific metamorphic belt| and Oligocene-Miocene regional metamorphism in the Himalayan orogen. (C) 1998 Elsevier Science B.V. All rights reserved. 4514,1998,3,3,Methane production of raw and composted solid waste in simulated landfill cells,Methane contributes approximately 20% to the annual increase in global warming| and is explosive at concentrations of 5 to 15% in air. Landfills are the origin of approximately 15% of the total global methane emissions. This study was conducted to determine the potential decrease in methane production from municipal landfills if the organic components of solid waste (SW) are composted Frier to landfilling. The quantities and rates of methane production were measured using simulated landfill cells containing composted and raw simulated SW. The SW was composted in an open pile and characterized by temperature| pH| ash content and CO(2) evolved during aerobic respiration. Assuming a 10% lignin content| the labile carbon fraction was reduced by an estimated 71% during composting. Over a 6-month period| simulated landfill cells filled with raw waste generated 66 liters methane per kg of dry refuse| while cells containing composted SW produced 31 liters methane per kg of dry compost. Per unit weight of the original dry raw SW| composted SW placed in a simulated landfill environment produced only 15 liters methane per kg dry raw SW which is 23% of the methane that was generated when the raw SW was placed directly in the simulated landfill cells. 4620,1998,2,3,Missing sinks| feedbacks| and understanding the role of terrestrial ecosystems in the global carbon balance,Terrestrial ecosystems are thought to be a major sink for carbon at the present time. The endeavor to find this terrestrial sink and to determine the mechanisms responsible has dominated terrestrial research on the global carbon cycle for years. Some of the mechanisms advanced to explain the "missing sink" are also negative feedbacks to a global warming. Here we distinguish between mechanisms likely to act as feedbacks to a global warming and other mechanisms consistent with a terrestrial sink that are not feedbacks to a global warming. One of the postulated negative feedback mechanisms that also helps explain the current "missing sink" is based on the theory that carbon should accumulate in vegetation as a result of a warming-enhanced mineralization of nitrogen in soil organic matter. The theory assumes that mineralized N is neither retained in the soil (through reimmobilization by microbial biomass) nor lost from the ecosystem| but rather becomes available for plant growth. None of these assumptions is supported yet by field data. In contrast| trends across existing climatic gradients suggest that warmer temperatures will lead to a decrease in the C:N ratio of soils (i.e.| the mineralized N remains in soil). Data pertaining to temporal variability in the global carbon balance are conflicting with respect to the question of whether increasing temperatures cause a release or storage of terrestrial carbon. The answer seems to depend in part on time scale. Most likely| multiple mechanisms| including some that release carbon and others that accumulate it| account for the present net accumulation of carbon on land. However| a positive feedback between temperature and the release of CO(2) to the atmosphere by terrestrial respiration seems likely to grow in importance and could change significantly the role that terrestrial ecosystems play in the global carbon balance. 4484,1998,2,4,Model estimates of methane emission from irrigated rice cultivation of China,A model developed by the authors (Huang et al. 1998) was further validated against field measurements from various regions of the world and calibrated to estimate methane emission from irrigated rice cultivation of China. On the basis of available information on rice cultivated area| growth duration| grain yield| soil texture and temperature| methane emission from Chinese rice paddies was estimated for 28 rice cultivated provinces in mainland. The calculated daily methane emission rates| on a provincial scale| ranged from 0.15 to 0.86 g m(-2) with an average of 0.32 g m(-2). Five of the top six locations with higher daily methane emissions are located at a latitude between 28 degrees and 31 degrees N. A total amount of 9.66 Tg (1 Tg = 10(12) g) CH(4) per year| ranging from 7.19 to 13.62| was estimated to be released from Chinese rice paddy soils. Of the total| 45% is emitted from the single-rice growing season| and 19% and 36% are from the early-rice and the late-rice growing seasons| respectively. Approximately 70% of the total is emitted in the region located at latitude between 25 degrees and 32 degrees N. The emissions from rice fields in Sichuan and Hunan Province were calculated to be 2.85 Tg y(-1)| accounting for approximate to 30% of the total. Comparisons of the estimated and the observed emission rates show that the estimates were| in general| close to the measurements at most locations. 4664,1998,4,3,Modelling global warming and Antarctic sea-ice changes over the past century,An atmosphere-sea-ice model is used in combination with results from a coupled atmosphere-ocean-sea-ice model to examine the changes of the Antarctic sea-ice cover influenced by atmospheric circulation associated with the global sea-surface temperature (SST) changes alone over the past century. Using the current climatological SST of Reynolds for forcing| a reasonable seasonal simulation of the Antarctic sea-ice cover for the present climate (including ice concentration| thickness and coverage) is obtained. When global SST anomalies for the past century (derived from the coupled atmosphere ocean-sea-ice model) are imposed| sea ice becomes more extensive| on the annual average| by 0.7-1.2 degrees of latitude| more compact by about 5-7%| and thicker by 7-13 cm| than at present. These changes are similar to those simulated from changes in greenhouse gases using the coupled atmosphere-ocean-sea-ice model which gave corresponding changes of about 0.8 degrees of latitude in extent| 6% in ice concentration and 12 cm in ice thickness. The simulated change in annual mean global surface temperature by the coupled atmosphere-ocean-sea-ice model was 0.7 K (0.6 K over the ocean including sea ice) which is similar to the observed change. Over the Antarctic the corresponding simulated change is 1.2 K which also appears compatible with observations. 4663,1998,2,4,Modelling the long-term response of the Antarctic ice sheet to global warming,The primary effects of global warming on the Antarctic ice sheet can involve increases in surface melt for limited areas at lower elevations| increases in net accumulation| and increased basal melting under floating ice. For moderate global warming| resulting in ocean temperature increases of a few OC| the barge increase in basal melting can become the dominant factor in the long-term response of the ice sheet. The results from ice-sheet modelling show that the increased basal melt rates lead to a reduction of the ice shelves| increased strain rates and flow at the grounding lines| then thinning and floating of the marine ice sheets| with consequential further basal melting. The mass loss from basal melting is counteracted to some extent by the increased accumulation| but in the long term the area of ice cover decreases| particularly in West Antarctica| and the mass loss can dominate. The ice-sheet-ice-shelf model of Budd and others (1994) with 20 km resolution has been modified and used to carry out a number of sensitivity studies of the long-term response of the ice sheet to prescribed amounts of global warming The changes in the ice sheet are computed out to near-equilibrium| but most of the changes take place within the first few thousand years. For a global mean temperature increase of 3 degrees C with an ice-shelf basal melt rate of 5 m a(-1) the ice shelfs disappear within the first few hundred years| and the marine-based parts of the ice sheet thin and retreat. By 2000 years the West Antarctic region is reduced to a number of small| isolated ice caps based on the bedrock regions which are near or above sea level. This allows the warmer surface ocean water to circulate through the archipelago in summer| causing a large change to the local climate of the region. 4679,1998,3,3,Modelling vehicle emissions using the TEMIS program - Part 2: case studies,Many challenges are associated with the ever increasing level of energy consumption and the damage to the environment caused by the pollutants from all sectors. On the local level the problem is associated with matters such as noise and air pollution| while on the global level the problems are associated with acid rain| ozone layer depletion and the greenhouse effect (global warming). The transport sector is a major contributor in this respect. The use of appropriate decision-making tools to assist in the assessment of alternative transport policies is required urgently. One such tool is the TEMIS program which was described in Part 1 of this investigation| where the methodology for the enhancement of TEMIS was reported. The enhanced version of TEMIS has subsequently been used to model the effects of different transport scenarios in order to improve future fuel economy and the adverse effects of air emissions as well as the greenhouse gases. In the present paper| three main case studies have been considered to test the effect of different scenarios tin terms of alternative fuels and technical advances) on energy consumption and emissions: firstly| the switch to alternative fuels| through investigating the effects of switching from petrol to diesel| secondly| the effects of switching from diesel to bio-diesel (for buses) and| finally| the effects of technical advances (three-way catalytic converters) and the effects on fuel consumption and emissions are considered. 4576,1998,2,4,Mosquito-borne arboviruses in Australia: the current scene and implications of climate change for human health,Of the mosquito-borne arboviruses| the encephalitic Murray Valley encephalitis and Kunjin viruses are a major public health concern| but the arthritides Ross River and Barmah Forest viruses are more important in a public health sense| being responsible for a far greater number of infections. Reported cases of Ross River totalled approximately 30 000 during 1991-1996; there have been several widely separated outbreaks of Barmah Forest in recent years and case reports are increasing annually. Surveillance programmes have increased our understanding of the geographic regions| climatic conditions and vector factors associated with viruses. Virus activity is widespread but is often localised| is driven primarily by mosquito abundance and various species are involved; host factors are involved also| but are not well understood. Typically| mosquito populations are governed by availability of habitat and environmental conditions. Models of climate change predict increases in rainfall| tides and temperature for parts of Australia| and such changes have the potential to increase the risk of arbovirus transmission by increasing the distribution and abundance of vectors| and duration of mosquito and arbovirus seasons. However| the amplitude of climate change is uncertain and the ecology of arbovirus transmission is complex. It is likely that some areas will have increases in arbovirus activity and human infection with predicted climate change| but risk of increased transmission will vary with locality| vector| host and human factors. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd. 2342,1998,2,4,Mountain lakes; Sensitivity to acid deposition and global climate change,Lakes in mountainous areas are of special interest in environmental studies because such lakes are generally particularly sensitive to inputs of atmospheric pollution and to changes in climate. Mountain lakes provide| therefore| an early warning of more widespread environmental changes. Surveys of lake-water chemistry in mountain areas in Norway| and mountain areas elsewhere in Europe which have crystalline bedrock| clearly show that such lakes are generally very dilute with low concentrations of base cations| alkalinity and SO42-. Mountain lakes also have low concentrations of total-P and TOC. The low concentrations of inorganic and organic ions are due to several factors of which low weathering rates| thin soils| high water fluxes and sparse vegetation in the catchment are of major importance. NO| concentrations on the other hand| are often higher in mountain lakes relative to low elevation lakes in the same area| due to the lower retention capacity of atmospherically deposited N in mountain catchments. 4666,1998,3,4,Natural replacements for ozone-depleting refrigerants in eastern and southern Asia,A computer model has been written to predict the consumption of refrigerants for vehicle air conditioning in China| India| South Korea and South-East Asia| their effect on ozone depletion and global warming| and their costs. A simple logarithmic relationship between per capita income and population growth rate is assumed. Correlations between vehicle ownership and air-conditioning usage are obtained from worldwide data. Both synthetic HFC (134a) and natural (hydrocarbons) refrigerants are considered. Sample calculations| assuming reasonable economic growth rates| predict that the use of hydrocarbons will lead to significant reductions in global warming potential and large savings in cost. The synthetic HFC option will incur costs exceeding a billion US dollars per year after the year 2005. (C) 1998 Elsevier Science Ltd and IIR. AII rights reserved. 4606,1998,3,4,Natural resource management in mitigating climate impacts: the example of mangrove restoration in Vietnam,The risk that tropical storm occurrence may alter as a result of global warming presents coastal managers| particularly in vulnerable areas| with a serious challenge. Many countries are hard-pressed to protect their coastal resources against present-day hazards| let alone any increased threat in the future. Moreover| the threat posed by climate change is uncertain making the increased costs of protection difficult to justify. Here| we examine one management strategy| based on the rehabilitation of the mangrove ecosystem| which may provide a dual| "win-win" benefit in improving the livelihood of local resource users as well as enhancing sea defences. The strategy|therefore|represent a precautionary approach to climate impact mitigation. This paper quantifies the economic benefits of mangrove rehabilitation undertaken| inter alia| to enhance sea defence systems in three coastal Districts of northern Vietnam. The results of the analysis show that mangrove rehabilitation can be desirable from an economic perspective based solely on the direct use benefits by local communities. Such activities have even higher benefit cost ratios with the inclusion of the indirect benefits resulting from the avoided maintenance cost for the sea dike system which the mangrove stands protect from coastal storm surges. (C) 1998 Elsevier Science Ltd. All rights reserved. 4647,1998,3,3,Nitrogen removal and N2O emission in a full-scale domestic wastewater treatment plant with intermittent aeration,Nitrous oxide (N2O) is emitted from wastewater treatment processes. It is known as a greenhouse gas that contributes to global warming (over 200 times more per molecule than carbon dioxide) and to the destruction of the ozone layer. It is therefore of great importance to develop technology that can suppress N2O emission. The effects of an anoxic period on N2O emission and nitrogen removal were investigated in an actual domestic wastewater treatment plant. When operated with intermittent aeration| most of the N2O was emitted into the atmosphere during the aerobic period. N2O emission from the intermittent process was estimated to be 0.43-1.89 g N2O person(-1) year(-1). Maintaining a dissolved oxygen (DO) concentration of over 0.5 mg l(-1) during the aerobic period resulted in the complete conversion of the influent NH4-N to NO3-N and a 60-min anoxic period was sufficient for denitrification to be completed. The findings show that an optimum combination of aerobic and anoxic conditions and their suitable control are very important for improving nitrogen removal efficiency and controlling N2O emission. 4559,1998,2,4,Nitrous oxide emissions from a fallow and wheat field as affected by increased soil temperatures,In order to determine the effects of increased soil temperature resulting from global warming on microbiological reactions| a 21-month field experiment was carried out in the Bavarian tertiary hills. The major objective was to focus on N2O releases as either a positive or negative feedback in response to global warming. The soils of a fallow field and a wheat field were heated 3 degrees C above ambient temperature and N2O fluxes were measured weekly from June 1994 to March 1996| During the experimental period| measured temperature differences between the control plots and the heated plots were 2.9+/-0.3 degrees C at a depth of 0.01m and 1.0-1.8 degrees C at a depth of 1 m| Soil moisture decreased with the elevated soil temperatures of the heated plots| The mean differences in soil moisture between the treatments were 6.4% (fallow field) and 5.2%(DW) (wheat field dry weight| DW)| respectively. Overall N2O releases during the experimental period from the fallow field were 4.8 kg N2O-N ha(-1) in the control plot against 5.0 kg N2O-N ha(-1) in the heated plot| and releases from the wheat field were 8.0 N2O-N ha(-1) in the control plot and 7.6 N2O-N kg ha(-1) in the heated plot. However| on a seasonal basis| cumulated N2O emissions differed between the plots. During the summer months (May-October)| releases from the heated fallow plot were 3 times the rates from the control plot. in the winter months| N2O releases increased in both the fallow and wheat fields and were related to the number of freezing and thawing cycles. 4660,1998,3,2,Nuclear power in the global energy-environmental system,Reducing the CO2 emission to cope with the global warming is one of the most challenging issues for the global energy system. Among various technological options for reducing the CO2 emissions from energy production| nuclear power is expected to play a key role if accepted by the society. However| there have been fewer model analyses reported recently on the role of nuclear power in the global energy system when compared with the analyses of the other options such as energy efficiency improvements| renewable energies| and CO2 recovery and disposal. This paper presents| with a newly developed global energy model| a numerical analysis on the value of nuclear option in the global energy system| particularly in terms of CO2 mitigation. With the global energy model| which finds the cost minimum energy system over the time range of 1995-2055| the value of nuclear power is analyzed. The model incorporates detailed descriptions of energy conversion technologies which include| besides electricity generation| various liquefaction and gasification processes of hydrocarbon fuels with the options of CO2 recovery and disposal. For nuclear technologies| LWRs (light water reactors) and FBRs (fast breeder reactors) are taken into account with fuel cycle options. Major findings are: 1) LWRs would be introduced at the maximum level into the cost minimum energy system if their economics is slightly improved from the standard assumption; however| 2) the maximum introduction of LWRs would make only a small effect in reducing the global CO2 emissions; 3) FBRs would be introduced at an almost maximum scale when the stabilization of global CO2 emission is required; 4) the role of FBRs in reducing the global CO2 emission is very robust against the deterioration of their economics; and 5) IGCC (integrated coal gasification combined cycle power generation) with CO2 recovery would replace the role when FBRs are not introduced| (C) 1997 Published by Elsevier Science Ltd. 4564,1998,5,3,Oceanic plateau formation: a cause of mass extinction and black shale deposition around the Cenomanian-Turonian boundary?,The Cenomanian-Turonian boundary (90.4 Ma) represents a major period of worldwide environmental disturbance. The physical manifestations of this are: elevated atmospheric and oceanic temperatures; a significant sea-level transgression; and a period of widespread anoxia| leading to the formation of oceanic black shales| and the extinction of 26% of all genera. Elevated delta(13)C values and enrichment of trace elements in Cenomanian-Turonian boundary sediments| combined with a reduction in Sr-87/Sr-86| also imply a severe environmental perturbation. At this time oceanic crustal production rates reached their highest level of the last 100 million years. This was principally caused by extensive melting of hot mantle plumes at the base of the oceanic lithosphere| and the development of vast areas (up to 1 x 10(6) km(2)) of thickened oceanic crust in the Pacific and Indian Oceans. The anomalous volcanism associated with the formation of these oceanic plateaux may have been responsible for the environmental disturbances c. 90 Ma. These eruptions would also have resulted in the emission of large quantities of CO2 into the atmosphere| leading to global warming. Additionally| the emission of SO2| H2S| CO2 and halogens into the oceans would have made seawater more acidic resulting in the dissolution of carbonate| and further release of CO2. This run-away greenhouse effect was probably put into reverse| by the decline of the anomalous Volcanic activity| and by increased (CO2-driven) productivity in oceanic surface waters| leading to increased organic carbon burial| black shale deposition| anoxia and mass extinction in the ocean basins. 4569,1998,2,4,On the climate forcing of carbon monoxide,Carbon monoxide plays a primary role in governing OH abundances in the troposphere. It is likely that through this chemical interaction| CO plays an important role in climate forcing by affecting CH4 concentrations. We use a photochemical box model to estimate the indirect global warming potential (GWP) of tropospheric carbon monoxide resulting from its effect on methane abundances. We also consider indirect GWPs of CO due to carbon dioxide production and possible CO GWP ranges due to ozone production to estimate a total CO indirect GWP range over various time horizons. We estimate that for current emission levels| the short-term (<15 years) cumulative radiative forcing due to the direct anthropogenic emission of CO may be larger than the cumulative forcing due to anthropogenically emitted N2O. 4502,1998,3,3,On the study of energy performance and life cycle cost of smart window,With worldwide energy cost rising significantly| there has been a pressing need to reduce the burning of fossil fuels and subsequently energy consumption. This| coupled with the prospect of global warming threatening human habitation| has made countries including Singapore more conscious and aware of the energy problem at hand. This paper deals with smart window| a double glazing unit where one pane consists of a high-performance heat reflective glass and the other coated with low-emissivity (low-e) coating. This combination of glazing provides optimum energy efficiency and a high level of daylight transmission with minimal reflectance. A study is made on the benefits derived from smart window done on a hypothetical 20-storey building. This encompasses a description of its quantitative impact on cooling load| energy consumption and energy savings achieved as compared with other forms of glazing. Following this| a detailed life cycle costing is done to determine the economic benefits attained from this type of glazing. The reduction of atmospheric pollutants as a result of using smart window is also analysed| and the future application of the glazing in hot and humid climates is discussed. In conclusion| it is observed that the smart window meets the technical and economic targets set| thus making it a viable long-term investment for high-rise commercial buildings. (C) 1998 Elsevier Science S.A. All rights reserved. 4530,1998,2,3,Past and future carbon balance of European ecosystems from pollen data and climatic models simulations,As climate changes| there is considerable uncertainty whether northern hemisphere ecosystems will act as atmospheric CO2 sinks or sources. Here| we used statistical models calibrated on field measurements| past terrestrial biomes and climates inferred from pollen and future climatic change scenarios simulated by General Circulation Models (GCMs)| to investigate the processes controlling past| present and future CO2 fluxes in the European ecosystems. Our results suggest that climatic change can significantly affect spatial and temporal variations of net primary production and soil respiration| and alter the net ecosystem exchange of CO2. Most of the potential terrestrial biomes in Europe will likely change from a net CO2 sink| which provided a negative feedback for atmospheric CO2 during the last 13 000 yr BP| to a net CO2 source| providing a positive feedback following global warming. The results further illustrate that there is no analogue in the recent past (Late Quaternary) for the probable future ecosystem dynamics. (C) 1998 Elsevier Science B.V. All rights reserved. 4482,1998,2,3,Phenology and growth of shoots| needles| and buds of Douglas-fir seedlings with elevated CO2 and (or) temperature,Increased atmospheric CO2 and global warming may affect overall tree growth| but impacts of these combined stresses are largely unknown in terms of multiple growing season impacts on specific flushes. Thus| the effects of ambient or elevated CO2 (approximately 200 mu mol.mol(-1) above ambient) and ambient or elevated temperature (approximately 4 degrees C above ambient) were evaluated for both main and second (lammas) flushes of Douglas-fir (Pseudotsuga menziesii (Mirb.) France). Established seedlings were grown for three full growing seasons in outdoor| sunlit chambers| which maintained diel and seasonal variation in climate. A reconstructed forest soil was used with a seasonal wet and dry cycle and without added fertilizer. Compared with ambient CO2 elevated CO2 had no impact on overall phenology and growth of terminal shoots| needles| or buds. In contrast| compared with ambient temperature| elevated temperature resulted in higher shoot and needle growth rates early in the season; reduced final terminal shoot length; and either reduced| increased| or unchanged final needle length| depending on season. Initiation of the lammas flush was delayed and (or) decreased at elevated temperature. Leading terminal bud break and growth occurred earlier; however| resting bud length was reduced| and bud width tended to increase with elevated temperature. Thus| at least during early seedling growth| elevated temperatures may reduce both main- and lammas-flush growth| thereby altering tree productivity| whereas elevated CO2 may have little effect on main or lammas growth at either the current or elevated temperature. 4609,1998,2,4,Photosynthetic acclimation to temperature and drought in the endemic chelan rockmat| Petrophytum cinerascens (Rosaceae),Petrophylum cinerascens (Piper) Rydb. (Rosaceae) is a highly restricted endemic found on steep rocky outcrops and sandy soils along the Columbia River in eastern Washington. Our goal was to examine the plant's ability for photosynthetic acclimation to increased growth temperature. Plants collected from the field were subjected to three sets of day/night growth temperatures and to two different watering regimes. Leaf gas exchange was measured at step-intervals of leaf temperature. Data were fitted to individual temperature response curves| and the optimum temperature for assimilation (T-opt)| the high temperature compensation point (T-high) and assimilation rate at the optimum temperature for assimilation (A(opt)) were calculated from the regressions. We analyzed the data using a 3 x 2 split plot experimental design with growth temperature as the main effect and watering treatment as the split plot factor. A(opt) for plants grown at 30/16 and 34/20 C was significantly greater than that for plants grown at 38/24 C| but the main effects of growth temperature on T-opt and T-high were not significant. The relative decrease in A(opt) from the lowest growth temperature to the highest was almost 60% for well-watered plants and over 20% for plants with periodic drought treatments. The lack of change in T-opt and T-high| coupled with the decrease in A(opt) with increased growth temperature| suggests that P. cinerascens is not able to acclimate to increased global temperature and therefore may serve as a sensitive indicator species of global warming. 4552,1998,2,4,Physiological effects of sublethal acid exposure in juvenile rainbow trout on a limited or unlimited ration during a simulated global warming scenario,Changes in the physiology and cost of living of fish were studied during exposure to simulated global warming and environmental acidification| alone and in combination. Trout were exposed to slightly elevated water temperatures (+2 degrees C)| in the presence and absence of sublethal acidity (pH 5.2) in synthetic softwater for 90 d (8 degrees-12 degrees C). Fish were either fed to satiation (ca. 1%-3% of their wet-body weight daily) or fed 1% of their wet-body weight once every 4 d. Satiation-fed fish exposed to sublethal pH showed no ionoregulatory disturbances but exhibited increased appetites and growth compared to fish in control pH waters. In contrast| fish maintained on a limited ration did not grow and showed typical ionoregulatory responses to acid stress| with lower whole-body Na+ and Cl- concentrations and greater mortality. Detrimental effects were greater in the global warming scenario (+2 degrees C). Overall| a slight temperature increase and sublethal pH increased the cost of living as determined by increased food consumption in satiation-fed fish and greater mortalities in fish maintained on a limited ration. Most important| these findings suggest that fish given sufficient food can compensate for increased energy expenditure or difficulties in maintaining ion balance associated with low pH exposure. 4669,1998,3,4,Plantation forestry in Brazil: Projections to 2050,Brazil is fortunate in having large areas of land that are not currently forested but that are suitable for silvicultural plantations. Changes in the area and regional distribution of the country's silvicultural plantations imply a wide variety of environmental and social impacts. Projections of future development of plantation silviculture are needed for analyzing these impacts| as well as to serve as a reference scenario for evaluating the potential effects of climatic change on Brazil's plantations| and for the related task of evaluating the implications of proposals to combat global warming by increasing the area of silvicultural plantations in Brazil beyond the extent to which they would otherwise expand. Such a reference scenario provides the control| or "business as usual" standard| against which one can compare the situation as affected by climatic change and/or by additional silvicultural or other activities carried out to help mitigate climatic change. Assuming constancy of climate| technology| per-capita consumption of wood products| and Brazil's share of international trade| the area of plantations in 2050 would be 3.2 times larger than the area in 1991. (C) 1998 Elsevier Science Ltd. All rights reserved. 4616,1998,3,4,Plasma etching of dielectric films using the non-global-warming gas CF3I,In this study| trifluoroiodomethane (CF3I)| a non-global-warming gas| has been investigated as a substitute for typical PFCs currently used in wafer patterning and CVD chamber cleaning processes. Dielectric films consisting of plasma enhanced chemically vapor deposited silicon dioxide and silicon nitride were comparatively etched in CF3I and C2F6/O-2 plasma environments. The etch rate of these films was ascertained as a function of applied rf power| etchant gas flow rate| reaction chamber pressure and CF3I:O-2 ratio. (C) 1998 Elsevier Science B.V. 4619,1998,3,4,Plasma etching of dielectric films with novel iodofluorocarbon chemistries: Iodotrifluoroethylene and 1-iodoheptafluoropropane,The use of two novel etch chemistries belonging to the iodofluorocarbon family| iodotrifluoroethylene and 1-iodoheptafluoropropane| has been investigated in a dielectric etch application. These substances are being explored as potential alternatives to perfluorocompounds| a fully fluorinated class of etchants that is presently in widespread use in dielectric etch processes. Whereas perfluorocompounds have global warming properties once emitted into the atmosphere| iodofluorocarbons such as those discussed in this work are presently believed not to possess long-term environmental impacts. Under the conditions tested| the two iodofluorocarbons discussed in this work have both been found to etch silicon dioxide films readily. Note that 1-iodoheptafluoropropane has also been found to be capable of etching silicon nitride films under these conditions. An Applied Materials Precision 5000 etch tool was used in this work. (C) 1998 American Vacuum Society. [S0734-2101(98)01202-0]. 2350,1998,2,4,Population trends of the Galapagos penguin: Impacts of El Nino and La Nina,The Galapagos Penguin (Spheniscus mendiculus) population probably has always been small and largely restricted to the islands of Fernandina and Isabela. Counts suggest the current population of Galapagos Penguins is likely between 4|250 and 8|500| half of what it was in the early 1970s. Population size has varied and declined probably because of substantial changes in oceanic conditions. Body condition as evidenced by weight is enhanced during cold surface water conditions| La Nina| and deteriorates when surface waters are warmed| El Nino| and under the most severe conditions| penguins starve. Analysis of a long-term data set from counts of the population suggests that the population has fluctuated| dropping precipitously after the 1982-1983 El Nino and has since then been recovering very slowly. This parallels the overall warming in the Pacific during the last 20 years associated with the more frequent El Nino and less frequent La Nino events. These trends suggest that long-term global climate warming is likely to threaten the Galapagos Penguin population particularly because the population is small and its distribution restricted. New threats from climatic warming and increasing human perturbations such as fishing| inadvertent discharge of petroleum products| and transport of potential predators and pathogens to islands increase the risk of extinction. 4490,1998,5,4,Portrait of a late paleocene (early Clarkforkian) terrestrial ecosystem: Big Multi Quarry and associated strata| Washakie Basin| Southwestern Wyoming,In-depth understanding of past climatic and biotic change requires the study of ancient ecosystems. However| terrestrial plants and vertebrates are preferentially preserved under very different taphonomic conditions| and diverse fossil floras and faunas are rarely found in close association. Big Multi Quarry and associated strata in the uppermost Fort Union Formation of the Washakie Basin| southwestern Wyoming| provide a uniquely detailed record of terrestrial fauna| flora| and climate during the early Clarkforkian. The Clarkforkian Land Mammal Age| approximately the last million years of the Paleocene| wars an interval of global warming that had profound biotic consequences. The mammalian fauna of Big Multi Quarry| consisting of 41 species| is the most diverse known from a single Clarkforkian locality. Unlike most other Clarkforkian faunas| this assemblage is not significantly biased against small forms. Lipotyphlan insectivores were dominant| and arboreally adapted taxa were abundant and diverse. The closely associated and well-preserved fossil plant assemblage was overwhelmingly dominated by a single species belonging to the birch family. Floral richness| heterogeneity| and evenness were as low as in the Tiffanian of the same region| showing that forest structure remained monotonous even as climate warned and mammals diversified in the Clarkforkian. The plant assemblage more closely resembles middle than early Clarkforkian floras of northern Wyoming| suggesting northward migration| of the ranges of plant taxa coincident with warming. A great deal of research has focused on the unusually warm interiors of continents in the terminal Paleocene and early Eocene. Multiple lines of evidence from our study| including sedimentological indicators| analyses of the nearest living relatives and functional analogues of the fossil plants and animals| size and margin analysis of fossil leaves| and cenogram analysis of the mammalian fauna| indicate that southwestern Wyoming had a humid subtropical climate with little or no seasonal frost or marked dry season| well before the terminal Paleocene. 2312,1998,2,4,Potential effects of differential day-night warming in global climate change on crop production,Recent studies on the nature of global warming indicate the likelihood of an asymmetric change in temperature| where night-time minimum temperature increases more rapidly than the daytime maximum temperature. We used a physically based scenario of asymmetric warming combined with climate change scenarios from General Circulation Models (GCMs) outputs and the EPIC (Erosion Productivity Impact Calculator) plant process model to examine the effects of asymmetric temperature change on crop productivity. Our results indicated that the potential effects of global change on crop productivity may be less severe with asymmetric day-night warming than with equal day-night warming. 4637,1998,2,4,Potential effects of global warming on the occurrence of Japanese pest insects,The potential effects of global warming on the occurrence of four types of Japanese pest insects were studied by developing a computer program. The number of generations of each insect under present thermal condition and after 2 degrees C warming at 960 locations in Japan where temperature data was measured by the AMeDAS system was estimated. Thermal summation and daylength models were used to describe insect development and deleterious effects of low and high temperatures on the insects. In most regions| a non-diapausing insect| Plutella xylostella would complete two additional generations compared to the present. In a winter diapausing insect| Chile suppressalis| the northern boundaries of zones of two and three generations would shift northward by about 300 km. A cold weather susceptible insect| Tribolium confusum| would expand its distribution area northward| but the northern front of its distribution would not shift markedly| except for in the central mountainous regions of the Main Island. Ephestia kuhniella| which is susceptible to hot weather| would not be able to occur in the western part of the Main Island and Shikoku and Kyushu Islands due to high temperatures in summer| leading to a large shrinkage in its distribution area in Japan. Our results demonstrated that the effects of global warming on insect occurrence would be significant| but should vary depending on the biological characters of the insects. 4512,1998,2,3,Potential effects of global warming on waterfowl populations breeding in the Northern Great Plains,The Prairie Pothole Region (PPR) of the Northern Great Plains is the most important breeding area for waterfowl in North America. Historically| the size of breeding duck populations in the PPR has been highly correlated with spring wetland conditions. We show that one indicator of climate conditions| the Palmer Drought Severity Index (PDSI)| is strongly correlated with annual counts (from 1955 to 1996) of both May ponds (R-2 = 0.72| p < 0.0001) and breeding duck populations (R-2 = 0.69| p < 0.0001) in the Northcentral U.S.| suggesting the utility of PDSI as an index for climatic factors important to wetlands and ducks. We then use this relationship to project future pond and duck numbers based on PDSI values generated from sensitivity analyses and two general circulation model (GCM) scenarios. We investigate the sensitivity of PDSI to axed changes in temperature of 0 degrees C| +1.5 degrees C| +2.5 degrees C| and +4.0 degrees C in combination with fixed changes in precipitation of -10%| +0%| +7%| and +15%| changes spanning the range of typically-projected values for this region from human-induced climatic change. Most (11 of 12) increased temperature scenarios tested result in increased drought (due to greater evapotranspiration under wanner temperatures) and declining numbers of both wetlands and ducks. Assuming a doubling of CO2 by 2060| both the equilibrium and transient GCM scenarios we use suggest a major increase in drought conditions. Under these scenarios| Northcentral U.S. breeding duck populations would fluctuate around means of 2.1 or 2.7 million ducks based on the two GCMs| respectively| instead of the present long-term mean of 5.0 million. May pond numbers would fluctuate around means of 0.6 or 0.8 million ponds instead of the present mean of 1.3 million. The results suggest that the ecologically and economically important PPR could be significantly damaged by climate changes typically projected. We make several recommendations for policy and research to help mitigate potential effects. 4612,1998,2,4,Potential impacts of climate change on species richness in mountain forests - An ecological risk assessment,In this ecological risk assessment we evaluated potential climate-induced vegetation changes in mountain forests of Central Europe and possible impacts on species richness. The analysis was performed on all 1 km grid points of the Swiss forest inventory (c. 11|500 points) as well as on two subsets representing the forested points within the geographical limits of two inventories of legally protected reserve areas. The core of the approach is (a) a conceptual model of the movement of climatic ranges along altitudinal gradients as a result of global warming and (b) a spatially explicit forest community simulator that predicts a potential natural vegetation unit for any given 1 km grid point of the Swiss forest inventory for both current climate and for altered climate regimes| The model is derived from empirical data featuring the relationships between quasi-natural vegetation types and measured site variables. Species richness for any modelled forest community is estimated on the basis of phytosociological releves. The conceptual model showed that out of 109 legally protected landscapes| sites and natural monuments of national importance (minimum area > 1 km(2)) about 40-50% have an altitudinal or degree-day range that is able to host migrating species within the reserve limits if climate is warming in a moderate way (increase of mean annual temperature between +1.0 and + 1.4 degrees C). In the case of strong warming (increase of mean annual temperature between + 2.0 and + 2.8 degrees C) only 20-30% fulfil this criterion. The spatially explicit forest simulator showed that under a temperature increase without simultaneous increase in precipitation (warmer and more xeric due to increased evapotranspiration| Fagus-dominated communities in the colline-submontane belt might eventually be replaced by oak-hornbeam (Carpinion) communities. In the montane belt| the dominance of conifers will be seriously threatened by an invasion of deciduous species from the low montane and submontane belt. Under warmer and wetter conditions the vegetation shifts might not be as drastic as under warmer and more xeric conditions and the shift towards oak and oak-hornbeam communities on the Plateau is not supported. Concerning species richness| the models showed that in the case of warmer temperatures and constant precipitation (warmer and more xeric due to increased evapotranspiration) overall species richness is increasing on all I km points of the Swiss Forest Inventory| as well as on all selected subsets representing the forested points within legally protected reserve areas| In the case of warmer and wetter conditions the risk assessment does not show any drastic changes in the long-term species richness. (C) 1998 Published by Elsevier Science Ltd. 2336,1998,2,4,Potential impacts of climate change on tropical Asian forests through an influence on phenology,Changes in plant phenology will be one of the earliest responses to rapid global climate change and could potentially have serious consequences both for plants and for animals that depend on periodically available plant resources. Phenological patterns are most diverse and least understood in the tropics. In those parts of tropical Asia where low temperature or drought impose a seasonal rest period| regular annual cycles of growth and reproduction predominate at the individual| population| and community level. In aseasonal areas| individuals and populations show a range of sub- to supra-annual periodicities| with an overall supra-annual reproductive periodicity at the community level. There is no evidence for photoperiod control of phenology in the Asian tropics| and seasonal changes in temperature are a likely factor only near the northern margins. An opportunistic response to water availability is the simplest explanation for most observed patterns where water is seasonally limiting| while the great diversity of phenological patterns in the aseasonal tropics suggests an equal diversity of controls. The robustness of current phenological patterns to high interannual and spatial variability suggests that most plant species will not be seriously affected by the phenological consequences alone of climate change. However| some individual plant species may suffer| and the consequences of changes in plant phenology for flower- and fruit-dependent animals in fragmented forests could be serious. 4575,1998,2,3,Potentially complex biosphere responses to transient global warming,Feedback interactions between terrestrial vegetation and climate could alter predictions of the responses of both systems to a doubling of atmospheric CO2. Most previous analyses of biosphere responses to global warming have used output from equilibrium simulations of current and future climate| as compared to more recently available transient GCM simulations. We compared the vegetation responses to these two different classes of GCM simulation (equilibrium and transient) using an equilibrium vegetation distribution model| MAPSS. Average climatologies were extracted from the transient GCM simulations for current and doubled (2 x) CO2 concentrations (taken to be 2070-2099) for use by the equilibrium vegetation model. However| the 2 x CO2 climates extracted from the transient GCM simulations were not in equilibrium| having attained only about 65% of their eventual 2 x CO2 equilibrium temperature change. Most of the differences in global vegetation response appeared to be related to a very different simulated change in the pole to tropic temperature gradient. Also| the transient scenarios produced much larger increases of precipitation in temperate latitudes| commensurate with a minimum in the latitudinal temperature change. Thus| the (equilibrium) global vegetation response| under the transient scenarios| tends more to a greening than a decline in vegetation density| as often previously simulated. It may be that much of the world could become greener during the early phases of global warming| only to reverse in later| more equilibrial stages. However| whether or not the world's vegetation experiences large drought-induced declines or perhaps large vegetation expansions in early stages could be determined by the degree to which elevated CO2 will actually benefit natural vegetation| an issue still under debate. There may occur oscillations| perhaps on long timescales| between greener and drier phases| due to different frequency responses of the coupled ocean-atmosphere-biosphere interactions. Such oscillations would likely| of themselves| impart further reverberations to the coupled Earth System. 4635,1998,3,3,Power generation for the twenty-first century: what role for nuclear?,A key element of the sustainable development challenge is meeting the world's future energy needs. With increasing industrialization in the developing world| the demand for electricity is growing. This has important implications for the security of supply of resources and environmental impacts. These issues bear especially on the continued use of fossil fuels for power generation. While there is uncertainty about ultimate fossil fuel reserves| they are finite and there must be concerns over the long-term security of supply. Perhaps of greater significance is the impact of increasing fossil use on the emission of greenhouse gases and the associated threat of global warming. While the need to give higher priority to increased efficiency| particularly in energy use is clear| it is necessary also to look to the increased use of non-fossil sources for power generation. This points to the future role for nuclear| which is the main focus for the present paper. The paper examines critically the barriers to the further development and wider use of nuclear power and their resolution. This is of vital importance if nuclear is to fulfil its potential in meeting the objectives of sustainable development. 4527,1998,4,2,Precipitation sensitivity to global warming: Comparison of observations with HadCM2 simulations,Recent century-long experiments performed with global climate models have simulated observed trends in global-mean temperature quite successfully when both greenhouse gas and aerosol forcing has been included. The performance of these same experiments in simulating observed global-scale changes in precipitation has not previously been examined. Here we use a gridded terrestrial precipitation dataset for the period 1900 to 1996 to examine the extent to which observed global and zonal-mean precipitation sensitivities to global warming have been captured by a series of model simulations recently completed by the UK Hadley Centre. There are signs that the model has been able to reproduce at least some of the observed zonal-mean variations in the precipitation sensitivity to warming. Questions remain both about the quality of the observed precipitation data and about the spatial scale at which anthropogenically-forced global climate models can be expected to reproduce observed variations in precipitation. 2324,1998,2,4,Predicting key malaria transmission factors| biting and entomological inoculation rates| using modelled soil moisture in Kenya,While malaria transmission varies seasonally| large inter-annual heterogeneity of malaria incidence occurs. Variability in entomological parameters| biting rates and entomological inoculation rates (EIR) have been strongly associated with attack rates in children. The goal of this study was to assess the weather's impact on weekly biting and EIR in the endemic area of Kisian| Kenya. Entomological data collected by the U.S. Army from March 1986 through June 1988 at Kisian| Kenya was analysed with concurrent weather data from nearby Kisumu airport. A soil moisture model of surface-water availability was used to combine multiple weather parameters with landcover and soil features to improve disease prediction. Modelling soil moisture substantially improved prediction of biting rates compared to rainfall; soil moisture lagged two weeks explained up to 45% of An. gambiae biting variability| compared to 8% for raw precipitation. For An. funestus| soil moisture explained 32% variability| peaking after a 4-week lag. The interspecies difference in response to soil moisture was significant (P < 0.00001). A satellite normalized differential vegetation index (NDVI) of the study site yielded a similar correlation (r(2) = 0.42 An. gambiae). Modelled soil moisture accounted for up to 56% variability of Art. gambiae EIR| peaking at a lag of six weeks. The relationship between temperature and An. gambiae biting rates was less robust; maximum temperature r(2) = -0.20| and minimum temperature r(2) = 0.12 after lagging one week. Benefits of hydrological modelling ore compared to raw weather parameters and to satellite NDVI. These findings can improve both current malaria risk assessments and those based on El Nino forecasts or global climate change model projections. 4657,1998,3,3,Prediction of blast furnace performance with top gas recycling,Top gas recycling has been suggested as a method for reducing blast furnace fuel rates and thus reducing carbon emissions from the ironmaking process. Three methods of top gas recycling are numerically investigated using a mathematical model to predict the furnace performance at fixed blast volume and constant coke| ore and pulverised coal compositions with varying recycle volumes. For each recycling method| a first calculation sequence is performed varying recycle volume at fixed ore:fuel ratio| and also a second sequence at fixed average liquid metal outflow temperature. Simple replacement of normal blast gases with recycled top gas is predicted to cause the production rate to decrease and the fuel rate to increase. Likewise| oxygen enriched blast replacement has similar effects| although the severity is less as the blast oxygen rate is maintained in this case. Both of these methods reduce furnace efficiency. Hot reducing gas (HRG) replacement| where CO2 is stripped from the recycled gas| leads to an increase in production of up to 25% with a simultaneous decrease in fuel rate of 20% at fixed metal temperature| These calculations show that top gas recycling could be used to increasing furnace efficiency while decreasing carbon emissions thus making a positive contribution to efforts to prevent global warming. 4631,1998,4,4,Prediction of methane production from dairy cows using existing mechanistic models and regression equations,Ruminants may contribute to global warming through the release of methane gas by enteric fermentation. Until now| methane emissions from ruminants were estimated using simple regression equations. The objective of this study was to compare the capacity of dynamic and mechanistic models to that of regression equations to predict methane production from dairy cows. The updated version of the model of Baldwin et al. and a modified version of the model of Dijkstra et al. and the regression equations of Blaxter and Clapperton and Moe and Tyrrell were challenged With 32 experimental diets selected from 13 publications. The predictive capacity-of mechanistic models and regression equations was evaluated by comparing predicted and observed methane production using regression analysis. Results of regression showed better prediction of methane production with mechanistic models than with regression equations. The modified model of Dijkstra et al. predicted methane production with the higher R(2) (.71) and the smaller error of prediction (19.87% of the observed mean). The model of Baldwin et al. predicted methane production with a similar R(2) (.70) but a higher error of prediction (36.93%). However| a large proportion of this error can be eliminated by a correction factor. Predictions using the equations of Moe and Tyrrell and Blaxter and Clapperton were poor (R(2) = .42 and .57; error of prediction = 33.72% and 22.93%| respectively). This study demonstrated that from a large variation in diet composition| mechanistic models allow the prediction of methane production more accurately than simple regression equations. 4638,1998,2,4,Projections at sea-level change in Hudson and James Bays| Canada| due to global warming,The potential impact of global warming on sea-level rise in the Hudson Bay area was examined. Land-based ice melt and thermal expansion of ocean waters were compared to isostatic rebound rates. Thermal expansion was estimated using a one-dimensional analysis and a three-dimensional world ocean general circulation model. It was found that the combined impact on sea-level rise of land-based ice melt and thermal expansion of the world ocean was the same order of magnitude as the sea-level fall rates due to isostatic rebound. Thus| there is the possibility of a cessation or reversal of sea-level fall in the Hudson Bay area in the next 100 yr. 4683,1998,3,2,Proposal of a new high-efficient gas turbine power generation| system utilizing waste heat from factories,It has been required to reduce the emission of CO2 for mitigating the global warming. As one of means for reducing CO2 emission| constructing high-efficient power generation systems is important| since the quantity caused by power generation is enormous and high-efficient system has a possibility to be widely installed from the economic point of view. In this paper| a H2O turbine power generation system utilizing waste heat from factories is proposed. In the proposed system| the steam produced by utilizing waste heat from factories is adapted as working fluid of a gas turbine. Thus| the system can be high efficient because the most part of a turbine output can be used for driving electric power generator: this is different with a conventional gas turbine power generation system where approximately two third of turbine output is consumed to compress the working fluid gas (air). Simulation programs have been developed by using object-oriented-language CSS lo evaluate various characteristics of the proposed system. The total exergetic efficiency of the system has been estimated to be 57.5% and the fuel-base exergetic efficiency to be 63.6%| when a refuse incineration plant has been taken as an example of waste-heat-emitting factories. The comparison with| the characteristics of a gas turbine system using a dual fluid cycle has also been performed. It has been shown that the proposed system has higher exergetic efficiency. The potential of CO2 reduction by installing the proposed system was also investigated. 2308,1998,3,4,Public perceptions of global warming: United States and international perspectives,National and international survey data on global warming are summarized in terms of levels of awareness| actual knowledge| degree of concern| perceived risk| and willingness to pay or sacrifice to mitigate or adapt to potential negative impacts. The data indicate the following: solid awareness of and support for general environmental goals; an awareness of and concern for global warming; a flawed understanding of global warming that is the result of an inappropriate application of a general pollution model; considerable perceived threat from global warming but less so than for most other issues; and a limited willingness to sacrifice to better cope with global warming. Although global warming generates concern around the globe| it is not a 'front-burner' issue. Concern tends to be highest in Canada| most of Europe and South America. Errors in assessing causes of global warming are global in nature. International data demonstrates considerable support for economic sacrifices to deal with environmental problems| including global warming. Our own data support but go beyond earlier data by implying that global warming is not a salient issue| and that people across the globe will support global climate change initiatives that do not levy unusual hardships; but they cannot be expected to voluntarily alter their lifestyles. 4517,1998,2,4,Rapid micro-evolution and loss of chromosomal diversity in Drosophila in response to climate warming,Concern regarding the ecological impact of rapid global warming has encouraged research on climate-induced changes in biological systems. Critical problems| still poorly understood| are the potential for rapid adaptive responses and their genetic costs to populations. The O chromosomal polymorphisms of Drosophila subobscura have been monitored at a southern Palearctic locality experiencing sustained climate warming since the mid-1970s. Observations suggest that the population is rapidly evolving in response to the new environmental conditions| and has lost a significant amount of chromosomal diversity (18.3% in 16 years). These findings are consistent with results from another population of D. subobscura| which is also undergoing climate warming| and are in accord with what would be expected from latitudinal and seasonal patterns of the various inversions. In addition| data on the O chromosomal polymorphisms from other localities throughout the range of this species suggest that other populations vary similarly. 4485,1998,2,4,Rates and magnitudes of paraglacial fan formation in the Garhwal Himalaya: implications for landscape evolution,The development of paraglacial fans| studied in the upper Bhagirathi valley| Garhwal Himalaya| northern India| relates to the retreat of the Gangotri Glacier over the last 200 years. These fans demonstrate the speed by which mass movement and fluvial processes may lead to the modification and readjustment of the Himalayan landscapes during deglaciation. The paraglacial fans in this region grew within approximately 100 years of deglaciation| and there after were modified by small debris flows and entrenched by fluvial incision. On the basis of the preservation of moraines which were deposited during the Last Glacial| total resedimentation of glacial sediments by mass movement and fluvial processes is estimated to occur over approximately 100|000 years in this region. A knowledge of the magnitude and frequency of development of paraglacial fans is essential for hazard mitigation and management in Himalayan environments where glaciers are presently retreating and are likely to retreat in the near future if global warming occurs. (C) 1998 Elsevier Science B.V. All rights reserved. 4617,1998,2,3,Recent increase in the length of the melt season of perennial Arctic sea ice,General circulation models predict that greenhouse gas induced global warming will be amplified in the Arctic as a result of temperature-albedo feedback. Whilst recent observations of decreasing Arctic sea ice extent are consistent with this scenario| the possibility that such a trend is attributable to local effects at the ice margins rather than to atmospheric warming cannot be dismissed. In the absence of direct air temperature measurements| warming over Arctic sea ice may be inferred from an increasing duration of the summer melt season. Analysis presented here of the dates of spring melt and autumn freeze-up observed over a large fraction of perennial Arctic sea ice using passive microwave data from the SMMR and SSM/I from 1979 to 1996 reveals an increase of 5.3 days (8%) per decade in the number of melt days per summer. 4542,1998,3,4,Reflections on the past and future of fusion and plasma physics research,Research in basic plasma physics and in controlled thermonuclear fusion are briefly compared. The development of fusion from the 1958 Geneva conference to present machines is sketched and intervening factors are analysed together with the interplay between smaller and larger thermonuclear machines. The importance of close ties between universities and fusion laboratories is underlined and the need for regrouping some of the latter| as machine size increases| is examined. The daunting size of the energy needs of mankind around 2050 as compared with supply and the threats of global warming demonstrate the crucial importance of constructing ITER| the international experimental reactor| very soon now that the necessary physical data have been obtained. It is our deep moral obligation to convince the public at large of the enormous promise and urgency of controlled thermonuclear fusion asa safe| environmentally friendly and inexhaustible energy source. 2373,1998,2,3,Regional impacts of climate change in the Arctic and Antarctic,Regional assessments of impacts due to global climate change are a high priority in the international programs on global-change research. Ill the polar regions| climate models indicate an amplification of global greenhouse warming| but there are large differences between the results of various models| and uncertainties about the magnitude and timing of the expected changes. Also| the observed high-latitude climate trends over the past few decades are much more regional and patchy than predicted by the models. As a first step in assessing possible climate impacts| model results are compared with observations of changes in temperature| precipitation| sea-ice extent| the permafrost regime and other cryospheric parameters. While considerable uncertainties remain in the long-term prediction of change| there is some agreement between model results and observed trends by season on shorter time-scales. The warming observed over the land masses of the Arctic over the past few decades is matched by corresponding observed decreases in snow cover and glacier mass balances| by thawing of the permafrost: and to a lesser degree by reductions in sea-ice extent. In Antarctica| warming in the Antarctic Peninsula and Ross Sea regions is associated with large decreases in ice-shelf areas and reduced ice thicknesses on the lakes in the McMurdo Dry Valleys. Major future impacts due to global greenhouse warming are likely to include permafrost thawing on land and its consequences for ecosystems and humans: changes in the productivity of marine ecosystems in the Arctic and Southern Ocean; economic impacts on fisheries; petroleum and other human activities; and social impacts on northern indigenous populations. Some of these impacts will have positive ramifications| but most are likely to be detrimental. While uncertainties exist about the future| climate change in the polar regions during the past few decades can he shown to have had major impacts already which will become much more pronounced if present trends continue. 4478,1998,2,2,Regional issues raised by sea-level rise and their policy implications,Global sea levels are rising and this change is expected to accelerate in the coming century due to anthropogenic global warming. Any rise in sea level promotes land loss| increased flooding and salinisation. The impacts of and possible responses to sea-level rise vary at the local and regional scale due to variation in local and regional factors. Policy responses to the human-enhanced greenhouse effect need to address these different dimensions of climate change| including the regional scale. Based on global reviews and analyses of relative vulnerability| 4 contrasting regions are selected and examined in more detail using local and national assessments. These regions are (1) Europe| (2) West Africa| (3) South| South-East and East Asia and (4) the Pacific Small Islands. Some potential impacts of sea-level rise are found to have strong regional dimensions and regional cooperation to foster mitigation approaches (to reduce greenhouse gas emissions and| hence| the magnitude of climate change) and adaptive solutions to climate change impacts would be beneficial. For instance| in South| South-East and East Asia subsiding megacities and questions about long-term deltaic management are common and challenging issues. The debate on mitigation and stabilisation of greenhouse forcing also requires information on regional impacts of different emission pathways. These results will be provided by integrated models| calibrated against national assessments. 4674,1998,3,2,Research and development on new synthetic routes for basic chemicals by catalytic hydrogenation of CO2,This paper gives a review of recent research work in catalytic hydrogenation of CO2 to various kinds of valuable chemicals and fuels. Recently| CO2 hydrogenation has been positively studied in relation to a possible countermeasure against global warming caused by CO2 emission. Advances in the effective syntheses of methanol| dimethylether| ethanol| lower paraffin| lower olefins| gasoline fraction| formic acid| acetic acid and others are introduced. Additionally the progress of solar hydrogen production for this CO2 fixation is described and its importance is pointed out. 4550,1998,2,4,Response of tundra plant biomass| aboveground production| nitrogen| and CO(2) flux to experimental warming,We manipulated air temperature in tussock tundra near Toolik Lake| Alaska| and determined the consequences for total plant biomass; aboveground net primary production (ANPP)| ecosystem nitrogen (N) pools and N uptake| and ecosystem CO| flux. After 3.5 growing seasons| in situ plastic greenhouses that raised air temperature during the growing season had little effect on total biomass| N content| or growing-season N uptake of the major plant and soil pools. Similarly| vascular ANPP and net ecosystem CO| exchange did not change with warming| although net primary production of mosses decreased with warming. Such general lack of response supports the hypothesis that productivity in tundra is constrained by the indirect effects of cold temperatures (e.g.| low nutrient availability or short growing-season length) rather than by cold growing-season temperatures per se. Despite no effect on net ecosystem CO| flux| air warming stimulated early-season gross photosynthesis (GP) and ecosystem respiration (ER) throughout the growing season. This increased carbon turnover was probably associated with species-level responses to increased air temperature. Warming increased the aboveground biomass of the overstory shrub| dwarf birch (Betula nana)| and caused a significant net redistribution of N from the understory evergreen shrub| Vaccinium vitis-idaea| to B. nana| despite no effects on soil temperature| total plant N| or N availability. Thus| although air warming had no effect on total ecosystem N pools| it did mediate N distribution within the plant community. The early-season stimulation of GP is consistent with warming effects on leaf expansion of dominant shrubs (including B. nana) observed in other studies in tussock tundra. The stimulation of ER probably resulted from maintenance and growth respiration associated with higher aboveground B| nana biomass production and higher root N uptake and/or turnover in the greenhouses. The species responses to warming are consistent with changes in plant species assemblages associated with past warming and suggest that future warming may increase the abundance of B. nana in tussock tundra. We conclude that a 4 degrees C rise in air temperature alone will significantly stimulate carbon turnover in tundra but will have little effect on net carbon balance. 4557,1998,2,4,Responses of tropical trees to rainfall seasonality and its long-term changes,Seasonality and physiognomy of tropical forests are mainly determined by the amount of annual rainfall and its seasonal distribution. Climatic change scenarios predict that global warming will result in reduced annual rainfall and longer dry seasons for some| but not all| tropical rainforests. Tropical trees can reduce the impact of seasonal drought by adaptive mechanisms such as leaf shedding or stem succulence and by utilization of soil water reserves| which enable the maintenance of an evergreen canopy during periods of low rainfall. Correlations between climate and responses of tropical trees are therefore poor and the responses of tropical rainforests to climatic changes are hard to predict. Predicted climate change is unlikely to affect the physiognomy of rainforests with high annual rainfall and low seasonality. Seasonal evergreen forests which depend on the use of soil water reserves will be replaced by more drought-tolerant semideciduous forests| once rainfall becomes insufficient to replenish soil water reserves regularly. As the limits of drought tolerance of tropical rainforests are not known| rate and extent of future changes cannot be predicted. 2332,1998,2,3,Rethinking the role of adaptation in climate policy,Since the late 1980s| scientists and policy makers have devoted considerable attention and resources to the issue of global climate change. Domestic and international policies in response focus primarily on prevention of future climate impacts on society through the mitigation of carbon dioxide emissions| Academic and political attention is also largely focused on issues of mitigation| Adaptation refers to adjustments in individual| group| and institutional behavior in order to reduce society's vulnerabilities to climate| and thus reduce its impacts. In 1996| the Intergovernmental Panel on Climate Change (IPCC) wrote that adaptation offers a 'very powerful option' for responding to climate change and ought to be viewed as a 'complement' to mitigation efforts. Yet| the IPCC also wrote that 'little attention has been paid to any possible tradeoff between both types of options'. This paper discusses the limitations of mitigation responses and the need for adaptation to occupy a larger role in climate policy. (C) 1998 Elsevier Science Ltd. All rights reserved. 4682,1998,4,5,Role of time-delay concept in understanding mechanism of total solar irradiance variation and its effect on the climate of the Earth,A time-delay concept is described to play a vital role in a hypothesis of the mechanism of the solar total irradiance variation driven by time variation of the thermal structure of the solar convection zone| with time scales on the order of 10 to 10 000 years. The hypothesis is formulated on an empirical basis from an analysis of the observed data of the magnetic field of the Sun and of the global land-ail temperature anomalies of the Earth| with the assumption that the land area of the Earth can be a good recorder of the solar total irradiance variation in the past. As a result of the assumption within the context of the present hypothesis| it was found that the solar total irradiance increase and the global warming of the Earth from the early 20th century to the present time could be caused by release of heat stored in the solar convection zone in the Maunder Minimum of the 17th century.
2315,1998,2,4,Root growth dependence on soil temperature for Opuntia ficus-indica: influences of air temperature and a doubled CO2 concentration,1. Root elongation as a function of soil temperature was determined for the CAM succulent Opuntia ficus-indica| under three different day/night air temperatures (15 degrees C/5 degrees C| 25 degrees C/15 degrees C and 35 degrees C/25 degrees C) and an ambient (360 mu mol mol(-1)) vs a doubled CO2 concentration (720 mu mol mol(-1)) at 25 degrees C/15 degrees C| the optimum temperature for net CO2 uptake. 2. Root elongation occurred at soil temperatures from 12 degrees C (at 15 degrees C/5 degrees C) to 43 degrees C (at 35 degrees C/25 degrees C) with optimum temperatures of 27-30 degrees C| similar to other CAM succulents and consistent with the distribution of this shallow-rooted species in warm regions. Although a doubled CO2 concentration did not alter the optimum or limiting soil temperatures| increases of up to 5 degrees C in these temperatures accompanied the 20 degrees C increase in day/night air temperatures. 3. Root elongation rates at optimum soil temperatures ranged from 5.4 mm day(-1) (15 degrees C/5 degrees C)| through 6.6 mm day(-1) (25 degrees C/15 degrees C)| to 10.4 mm day(-1) (35 degrees C/25 degrees C) with a 25% increase under a doubled CO2 concentration. Highest root elongation rates at 35 degrees C/25 degrees C may reflect changing root vs shoot sink strengths in a species with a highly plastic root system. 4. At limiting soil temperatures| the length of the cell division zone was reduced by an average of 20% and cell length at the mid-point of-the elongation zone by 10%. Increased root elongation rates under a doubled CO2 concentration reflected increased cell elongation. 5. The temperature response for the roots of O. ficus-indica and stimulation of elongation by a doubled CO2 concentration indicate that root growth for this highly productive species should be enhanced by predicted global climate change. 4641,1998,2,2,Simulated future sea-level rise due to glacier melt based on regionally and seasonally resolved temperature changes,Climate change is expected over the next century as a result of anthropogenic emissions of greenhouse gases and aerosols into the atmosphere| and global average sea level will consequently rise. Estimates' indicate that by 2100 sea level will be about 500 mm higher than today as a result of global warming| with thermal expansion of sea water accounting for over half of this rise. The melting of glaciers and ice sheets will contribute much of the remainder. We present an improved calculation of glacier melt| which uses the temperature patterns generated by a coupled atmosphere-ocean general circulation model(2|3) as inputs to a seasonally and regionally differentiated glacier model(4|5). Under specified greenhouse-gas and sulphate-aerosol forcings| our model predicts that glacier melt equivalent to 132 mm of sealevel rise will occur over the period 1990-2100| with a further 76 mm from melting of the Greenland ice sheet. These figures fall within the range of previous estimates made using simpler models(1); the advantage of our approach is that we take into account the effects of regional and seasonal temperature variations. Our inclusion of these effects increases the calculated glacier melt by 20%. 4626,1998,4,3,Simulated increase of hurricane intensities in a CO2-warmed climate,Hurricanes can inflict catastrophic property damage and loss of human life. Thus| it is important to determine how the character of these powerful storms could change in response to greenhouse gas-induced global warming. The impact of climate warming on hurricane intensities was investigated with a regional| high-resolution| hurricane prediction model. In a case study| 51 western Pacific storm cases under present-day climate conditions were compared with 51 storm cases under high-CO2 conditions| More idealized experiments were also performed. The large-scale initial conditions were derived from a global climate model. For a sea surface temperature warming of about 2.2 degrees C| the simulations yielded hurricanes that were more intense by 3 to 7 meters per second (5 to 12 percent) for wind speed and 7 to 20 millibars for central surface pressure. 4585,1998,2,2,Simulated response of the ocean carbon cycle to anthropogenic climate warming,A 1995 report(1) of the Intergovernmental Panel on Climate Change provides a set of illustrative anthropogenic CO2 emission models leading to stabilization of atmospheric CO2 concentrations ranging from 350 to 1|000 p.p.m. (refs 1-4). Ocean carbon-cycle models used in calculating these scenarios assume that oceanic circulation and biology remain unchanged through time. Here we examine the importance of this assumption by using a coupled atmosphere-ocean model of global warming(5) for the period 1765 to 2065. We find a large potential modification to the ocean carbon sink in a vast region of the Southern Ocean where increased rainfall leads to surface freshening and increased stratification(6). The increased stratification reduces the downward flux of carbon and the loss of heat to the atmosphere| both of which decrease the oceanic uptake of anthropogenic CO2 relative to a constant-climate control scenario. Changes in the formation| transport and cycling of biological material may counteract the reduced uptake| but the response of the biological community to the climate change is difficult to predict on present understanding. Our simulation suggests that such physical and biological changes might already be occurring| and that they could substantially affect the ocean carbon sink over the next few decades. 4588,1998,3,3,Simulating the impact of management practices on nitrous oxide emissions,Effective evaluation of alternative management strategies to control global warming requires tools for simulating emissions of N(2)O from soils across a range of soil properties| weather| and management inputs. We hypothesized that with modification to the nitrification and denitrification submodels of the Nitrate Leaching and Economic Analysis Package (NLEAP) model| we could simulate daily N(2)O emissions as a function of soil moisture| temperature| N content| and other factors. Field parameterization was conducted on an Ulm clay loam soil (a fine| montmorillonitic| mesic Ustollic Haplargid) and validation experiments for N(2)O gas emissions were performed on an on farm swine effluent study site on a Valent sandy soil (a mixed| mesic Ustic Torripsamment). The unitless model parameters reflecting the maximum fraction of selected N transformations emitted as N(2)O for nitrification (alpha(N))| wet-period denitrification (alpha(w))| and dry-period denitrifiation (alpha(d)) were calibrated as 0.065| 0.050| and 0.520 separately and then used in the validation study. The trends and magnitudes of simulated N(2)O emissions were statistically consistent|vith the results obtained from the field experiments (r = 0.78). Experimental results showed that the decline of N(2)O emission rates from 70 to 2 g N ha(-1) d(-1) during the growing season was related to soil N content decline from 33 to 4 mg kg(-1). Simulated effects of field management on annual N(2)O emissions indicated that plowing decreased N(2)O relative to notillage corn (Zea mays L.)| irrigation increased N(2)O 14% relative to dry-land corn| and doubling fertilization N rates from 100 to 200 kg ha(-1) increased N(2)O emissions 60%. 4536,1998,4,4,Soil carbon changes from conversion of forest to pasture in Brazilian Amazonia,Soils in Brazilian Amazonia may contain up to 136 Ct of carbon to a depth of 8 m| of which 47 Gt are in the top meter. The current rapid conversion of Amazonian forest to cattle pasture makes disturbance of this carbon stock potentially important to the global carbon balance and net greenhouse gas emissions. Information on the response of soil carbon pools to conversion to cattle pasture is conflicting. Some of the varied results that have been reported can be explained by effects of soil compaction| clay content and seasonal changes. Most studies have compared roughly simultaneous samples taken at nearby sites with different use histories (i.e.| 'chronosequences'); a clear need exists for longitudinal studies in which soil carbon stocks and related parameters are monitored over time at fixed locations. Whether pasture soils are a net sink or a net source of carbon depends on their management| but an approximation of the fraction of pastures under 'typical' and 'ideal' management practices indicates that pasture soils in Brazilian Amazonia are a net carbon source| with the upper 8 m releasing an average of 12.0 t C/ha in land maintained as pasture in the equilibrium landscape that is established in the decades following deforestation. Considering the equilibrium landscape as a whole| which is dominated by pasture and secondary forest derived from pasture| the average net release of soil carbon is 8.5 t C/ha| or 11.7 x 10(6) t C for the 1.38 x 10(6) ha cleared in 1990. Only 3% of the calculated emission comes from below 1 m depth| but the ultimate contribution from deep layers may be substantially greater. The land area affected by soil C losses under pasture is not restricted to the portion of the region maintained under pasture in the equilibrium landscape| but also the portion under secondary forests derived from pasture. Pasture effects from deforestation in 1990 represent a net committed emission from soils of 9.2 x 106 t C| or 79% of the total release from soils from deforestation in that year. Soil emissions from Amazonian deforestation represent a quantity of carbon approximately 20% as large as Brazil's annual emission from fossil fuels. (C) 1998 Elsevier Science B.V. All rights reserved. 4553,1998,2,4,Soil warming: Consequences for foliar litter decay in a spruce-fir forest in Maine| USA,Increased rates of litter decay due to projected global warming could substantially alter the balance hc tw een C assimilation and release in forest soils| with consequent feedbacks to climate change. This study was conducted to investigate the effects of soil warming on the decomposition of red spruce (Picea rubens Sarg|) and red maple (Acer rubrum L.) foliar litter at Howland| ME| Experimentally increased Oa horizon soil temperatures (increase of 4-5 degrees C) were maintained during the snow-free season from 1993 through 1995 in replicated 15 by 15 m plots using heat-resistance cables. For red maple litter| significant treatment effects included greater loss of mass (27%) and C (33%)| and greater accumulation of Zn (54%) during the first 6 mo of decay in the heated plots than the control plots| After 30 mo of decay| significant treatment effects were no longer evident for red maple litter. Few treatment effects were observed for red spruce litter during the initial 18 mo of decay. However| after 30 mo of decay| significant treatment effects included greater loss of mass (19%)| C (19%). N (24%)| Ca (27%)| Mg (12%)| K (4%)| Zn (60%)| and cellulose (40%) in red spruce litter in the heated plots than the control plots. We conclude that a modest increase in Oa horizon soil temperature ( 4-5 degrees C) ran significantly increase litter decay rates and alter litter decay dynamics in this coniferous forest stand| and that these changes exhibit variations in their temporal development as a function of species and litter quality attributes. 4483,1998,2,2,Solar cycle length hypothesis appears to support the IPCC on global warming,Since the discovery of a striking correlation between 1-2-2-2-1 filtered solar cycle lengths and the 11-year running average of northern hemisphere land air temperatures| there have been widespread speculations as to whether these findings would rule out any significant contributions to global warming from the enhanced concentrations of greenhouse gases. The 'solar hypothesis' (as we shall term this assumption) claims that solar activity causes a significant component of the global mean temperature to vary in phase opposite to the filtered solar cycle lengths. In an earlier article we have demonstrated that for data covering the period 1860-1980 the solar hypothesis does not rule out any significant contribution from man-made greenhouse gases and sulphate aerosols. The present analysis goes a step further. We analyse the period 1579-1987 and find that the solar hypothesis-instead of contradicting-appears to support the assumption of a significant warming due to human activities. We have tentatively 'corrected' the historical northern hemisphere land air temperature anomalies by removing the assumed effects of human activities. These are represented by northern hemisphere land air temperature anomalies calculated as the contributions from man-made greenhouse gases and sulphate aerosols by using an upwelling diffusion-energy balance model similar to the model of Wigley and Raper (1993) employed in the Second Assessment Report of The Intergovernmental Panel on Climate Change (IPCC). It turns out that the agreement of the filtered solar cycle lengths with the 'corrected' temperature anomalies is substantially better than with the historical anomalies| with the mean square deviation reduced by 36% for a climate sensitivity of 2.5 degrees C| the central value of the IPCC assessment| and by 43% for the best-fit value of 1.7 degrees C. Therefore our findings support a total reversal of the common assumption that a verification of the solar hypothesis would challenge the IPCC assessment of man-made global warming. (C) 1999 Elsevier Science Ltd. All rights reserved. 4529,1998,3,4,Solid sorption heat powered cycles for cooling and heat pumping applications,Heat powered solid sorption is a feasible alternative to electrical vapour compression. However| the emergence of that technology takes time. In this review| the possibilities and limits of this technology are analysed. The performances are shown to be very interesting and in progress| and right now applications are foreseen| The use of waste heat for solid sorption air-conditioning may be an attractive application| but| for a large dissemination| higher efficiencies as well as cost reduction are required. With respect to primary energy and global warming| sorption cooling and heat pumping is coherent| except for waste heat or solar applications| only if the cooling COP is larger than about 1 or 1.2 depending on operating conditions. Technical results are close to that point which provide a wider perspective. (C) 1998 Elsevier Science Ltd. All rights reserved. 4503,1998,3,3,Solid waste management in India: options and opportunities,In India| the collection| transportation and disposal of MSW are unscientific and chaotic. Uncontrolled dumping of wastes on outskirts of towns and cities has created overflowing landfills| which are not only impossible to reclaim because of the haphazard manner of dumping| but also have serious environmental implications in terms of ground water pollution and contribution to global warming. Burning of waste leads to air pollution in terms of increased TSP and PM10 emissions| which is equivalent to vehicular emissions at times. In the absence of waste segregation practices| recycling has remained to be an informal sector working on outdated technology| but nevertheless thriving owing to waste material availability and market demand of cheaper recycled products. Paper and plastic recycling have been especially growing due to continuously increasing consumption levels of both the commodities. Composting-aerobic and anaerobic| both the options are available to the country for scientific disposal of waste in future. However| country also needs something in terms of policy and guidelines to enable the municipal corporations to run the waste services efficiently. (C) 1998 Elsevier Science B.V. All rights reserved. 4504,1998,5,4,Some aspects of the Permian-Triassic boundary (PTB) and of the possible causes for the biotic crisis around this boundary,The first appearance datum (FAD) of Hindeodus parvus is an excellent datum very close to the base of the Otoceras woodwardi Zone (priority base of the Triassic). For the first time| it allows an exact correlation of the PTB in all marine facies and faunal realms. The following features of the extinction and recovery patterns near the PTB are most important for the search for causes of the PTB biotic crisis: (1) most strongly affected were the (siliceous) plankton (radiolarians) and the warm-water benthos and nekton; (2) most of the cold-water faunas were not significantly affected; (3) the recovery of the warm-water benthos and siliceous plankton occurred only after an unusually long time (during the late Olenekian and Middle Triassic); (4) the productivity of the terrestrial plants dropped strongly and the recovery was mainly in the upper Olenekian and in the Middle Triassic; (5) several terrestrial extinction events occurred at different levels within the Upper Permian| considerable before the marine PTB; at or close to the FAD of Lystrosaurus no extinction event in the terrestrial faunas can be observed; (6) terrestrial faunal elements that survived the Dzhulfian-Dorashamian extinctions were able to survive some months of extreme climatic conditions by hibernation-like life stages (vertebrates)| or by dry- and freezing-resistant eggs (conchostracans); (7) about 50% of the genera that disappeared at the PTB re-appeared in the Olenekian-Middle Triassic interval (Lazarus taxa)| or in this time interval genera appeared that had undoubtedly evolved from genera that had disappeared at the PTB; and (8) the PTB is preceded by mass occurrences of marine (and continental?) fungi| and the fungal spike ends abruptly a little before the PTB. A scenario for the PTB biotic crisis is elaborated that takes into consideration: the real (not interpolated) diversity patterns of different marine and continental fossil groups| the exact correlation of bioevents in different faunal realms and facies| the strong biotic crisis in the Tethyan warm-water faunas in contrast to the much weaker biotic event in cold-water faunas| the severe Dzhulfian-Dorashamian climate in many parts of the world caused by the continent-ocean configuration and by Siberian Trap volcanism| the cooling of the Boreal area by the northward drift of Pangaea that interrupted the exchange of warm-water benthos between the Tethys and western North America during the Guadalupian| the extinction event at the Guadalupian-Lopingian boundary that restricted most of the affected warm-water faunas to the Tethys| the importance of lower Scythian anoxia that reached an unusually shallow level| and above all the effects of the contemporaneous huge volcanic events about 250 m.y. ago on the Siberian Platform and in the eastern Tethys that caused a 3-6-months-lasting volcanic winter with strong cooling in low latitudes| followed by a strong global warming. (C) 1998 Elsevier Science B.V. All rights reserved. 4652,1998,4,2,Sources and sinks of methane in German agroecosystems in context of the global methane budget,Methane is an important greenhouse gas| which contributes about 20 % to global warming. The atmospheric CH(4) concentration is increasing rapidly| resulting from an imbalance between CH(4) production and consumption. On a global scale the most important CH(4) sources are wetlands| coal mining and natural gas exploration| enteric fermentation| rice paddies| and biomass burning. In German agriculture| animal husbandry is the sole| potent CH(4) source| which consists of methane from digestive processes and from generation in animal waste storages. For the year 1996 the total annual release from domesticated animals in Germany is estimated to 1.7 Tg CH(4)| of which 1.1 Tg originated from enteric fermentation and 0.6 Tg from animal wastes. Thus| German livestock contributed about 1.6 % to the global annual emission from enteric fermentation plus animal wastes. Arable soils and grasslands are important CH(4) sinks in agriculture. The contribution of German agricultural and forest soils to the globally estimated soil sink strength is about 0.3 %| but could also be as high as 1.1 %. For several reasons the CH(4) uptake potential is only partly exploited| as agricultural practices Like nitrogen fertilization and land use changes can have adverse impacts on the activity of CH(4) oxidizing bacteria in soil. In conclusion| more CH(4) flux measurements on German agricultural soils are needed to allow a more accurate estimate of their contribution to the global CH(4) budget. Additionally| further studies are required to improve the reliability of estimates for CH(4) emission from German livestock. 4636,1998,3,3,Status of worldwide coal mine methane emissions and use,Underground coal mines worldwide Liberate an estimated 29-41 x 10(9) m(3) of methane annually| of which less than 2.3 x 10(9) m(3) are used as fuel. The remaining methane is emitted to the atmosphere| representing the loss of a valuable energy resource. Methane is also a major greenhouse gas and is thus detrimental to the environment when vented to the atmosphere. Coal mine methane recovery and use represents a cost-effective means of significantly reducing methane emissions from coal mining| while increasing mine safety and improving mine economics. The world's ten largest coal producers are responsible for 90% of global methane emissions associated with the coal fuel cycle. China is the largest emitter of coal mine methane| followed by the Commonwealth of Independent States| or CIS (particularly Russia| Ukraine and Kazakhstan)| the United States| Poland| Germany| South Africa| the United Kingdom| Australia| India and the Czech Republic. Most of these countries use a portion of the methane that is liberated from their coal mines| but the utilization rate tends to be low and some countries use none at all. Coal mine methane is currently used for a variety of purposes. Methane is used for heating and cooking at many mine facilities and nearby residences. It is also used to fuel boilers| to generate electricity| directly heat air for mine ventilation systems and for coal drying. Several mines in the United States sell high-quality mine gas to natural gas distributors. There are several barriers to decreasing methane emissions by increasing coal mine methane use. Many of the same barriers are common to a number of the subject countries. Technical barriers include low-permeability coals| variable or low gas quality| variations in gas supply and demand and lack of infrastructure. Economic and institutional barriers include lack of information pertinent to development of the resource| lack of capital and low natural gas prices. A possible option for encouraging coal mine methane recovery and use would be international adoption of a tradeable permit system for methane emissions. (C) 1998 Elsevier Science B.V. 4593,1998,4,3,Study of global warming by GFDL climate models,This paper is based on the commemorative lecture which was delivered at the award ceremony of the Volvo Environmental Prize. The author describes his early attempt to study the greenhouse effect using a one-dimensional model of radiative| convective equilibrium of the atmosphere. This is followed by the description of a recent study of global warming which employs a general circulation model of the coupled atmosphere-ocean-land surface system developed at the Geophysical Fluid Dynamics Laboratory (GFDL). In particular| the study attempts to elucidate the role of oceanic and land surface processes in shaping the response of surface air temperature to a gradual increase in atmospheric carbon dioxide (CO2). 4511,1998,5,4,Sun| climate| hunger| and mass migration,Paleoclimatic studies indicate four epochs of global cooling during the last 4 000 years| i.e| during the few centuries before and after 2000 BC| 800 BC| 400 AD| and 1 600 AD; the quasiperiodicity corresponds to cyclic variation of solar activity. Global temperature changes influenced regional precipitation patterns: Northern Europe was wetter while the middle- and low-latitude lands were more aria during colder epochs. Both sets of cold climatical conditions were unfavorable for agricultural production. Historical records show that large demographic movements in history took place because of crop failures and mass starvation| rather than escaping from war zones. The "wandering" of the Germanic tribes during the first two or three centuries of the Christian Era is one example. Whereas the accelerated release of carbon dioxide from the burning of fossil fuels is ultimately to cause global warming| historical evidence indicates| however| that global warming has been on the whole a blessing to mankind. Global cooling| on the other hand| has curtailed agricultural production and has led to famines and mass migrations of people. Perhaps the most important task at the present is not so much computer-modelling of greenhouse effect on global climate| but water-management and agricultural researches to insure food-supply for an everincreasing world population. 4547,1998,3,4,Sustainable animal production systems in India: Issues and approaches,Sustainable animal production as applicable to small farm production system in Indian context has been discussed. Livestock farming systems practised are mainly traditional and guided by socio-economic considerations| available feed resources and market demand. The present status of livestock production and the contribution of livestock to Indian economy through milk| meat| egg| fibre and draught animal power (DAP) have been examined along with future perspectives. The major issues as related to animal production are (i) environmental degradation| (ii) low external input| (iii) impact of technologies on livestock improvement and resource base| and (iv) large number of ruminants and methane emission. Role and impact of technologies as related to animal health| breeding and reproduction| frozen semen| crossbreeding| feeds and feeding and institutional structure in improving livestock productivity and production have been examined. Effects of high livestock density| over grazing and desertification on natural resources and environment and that of large number of ruminants on global warming have been deliberated. Number of livestock specially cattle and buffalo| that can be sustained to meet the higher food needs| DAP| clean environment and maintenance of natural resources have been discussed. A sustainable model for higher productivity of livestock has been proposed. 4583,1998,3,3,Technological breakthrough for the environmental issues in Japan,We have reached the stage of having to implement a global warming prevention action plan for the 21st century. In this article we introduce the global energy scenario announced in the second report of the Intergovernmental Panel on Climate Change (IPCC) in 1995 enhanced by the developments after COP3 in Kyoto 1997| and specify technical development objectives for energy conservation| new energies and environment protection. Futhermore| a general idea of the 'Life Cycle Energy Revenue and Expenditure Balance' is introduced as a sustainable condition for evaluating future energy related technology development. This is shown for various electricity generation cycles. From the viewpoint of a social system giving priority to the environment the construction of an energy cascading and material circulation society becomes increasingly important. Sustainable economic activities are impossible without the 'Reverse Factory'| or complete recycling. Decentralization of the electric power generation| and electric power supply network will play an important role in solving environment and energy related problems. The future of individual transportation is outlined. Finally| the importance of technology transfer for internal globalization and international contribution for Japan| emphasizing the need for a technology network without national boundaries is pointed out. 2325,1998,2,4,Temporal perspectives in environmental surveillance: examples from the rocky intertidal zone,Data from 15 years' monitoring of rocky intertidal populations on the southeast coast of South Africa provide a long-term perspective of environmental variability| against which the generality of conclusions and predictions from short-term studies may be evaluated. Time series of population abundance of barnacles| rock oysters and limpets revealed a variety of temporal cycles| trends and periods of instability. Analyses of three-year segments of these time series| equivalent to the length of field observations in a typical doctoral study| revealed only high-frequency seasonal cycles in abundance. Only 30% of the segments exhibited the 'correct' long-term trends| although the slopes were different| whereas coefficients of variability were generally underestimated| by as much as fourfold. Similarly estimates of mean abundance were out by between two and four times. Multidimensional scaling ordinations of the entire species assemblage (approximately 12 species) revealed that the community occupies several distinct states| as defined by the relative abundance of component species. These states may persist for between 18 months and 5 years and in any three-year segment the community may change from one state to another further confounding analyses from short time series. Although short-term experimental studies are useful| for example in elucidating species interactions| this analysis indicates that short-term studies of population abundance shed little light on long-term dynamics and cannot be used as reliable predictors of population variability. It is argued that an understanding of the dynamics of natural populations requires data at much larger temporal scales than those from most current studies. This necessitates long-term programmes which transcend the three- to five-year horizon. Given the indicators of global climate change| the sooner more such programmes are initiated| the better. 2311,1998,4,4,Temporal variability of dimethylsulfide and dimethylsulfoniopropionate in the Sargasso Sea,Vertical profiles of dimethylsulfide (DMS) and beta-dimethylsulfoniopropionate| particulate (pDMSP) and dissolved (dDMSP)| were measured biweekly in the upper 140 m of the Sargasso Sea (32 degrees 10'N| 64 degrees 30'W) during 1992 and 1993. DMS and pDMSP showed strong| but different| seasonal patterns; no distinct intra-annual pattern was observed for dDMSP. During winter| concentrations of DMS were generally less than 1 nmol l(-1) at all depths| dDMSP was less than 3 nmol l(-1) and pDMSP was less than 8 nmol l(-1). In spring| concentrations of both dDMSP and pDMSP rose| on a few occasions up to 20 nmol l(-1) in the dissolved pool and up to 27 nmol l(-1) in the particulate pool. These increases| due to blooms of DMSP-containing phytoplankton| resulted in only minor increases in DMS concentrations (up to 4 nmol l(-1)). Throughout the summer| the concentrations of DMS continued to increase| reaching a maximum in August of 12 nmol l(-1) (at 30 m depth). There was no concomitant summer increase in dDMSP or pDMSP| The differences among the seasonal patterns of DMS| dDMSP| and pDMSP suggest that the physical and biological processes involved in the cycling of DMS change with the seasons. There is a correlation between the concentration of DMS and temperature in this data set| as required by some of the climate feedback models that have been suggested for DMS. A full understanding of the underlying processes controlling DMS is required to determine if the temperature-DMS pattern is of significance in the context of global climate change. (C) 1998 Elsevier Science Ltd. All rights reserved. 4541,1998,3,3,The climate change implications of manufacturing refrigerants - A calculation of 'production' energy contents of some common refrigerants,Total Equivalent Warming Impact (TEWI) analysis has been shown to be a useful aid to quantifying the climate change effect of potential emissions from the operation of systems that involve the use of greenhouse gases and consume energy| so generating CO2 emissions. It enables these systems to be optimized for minimum global warming impact. In previous studies(1|2|3)| the energies required to manufacture the greenhouse gases themselves were not included; by analogy with other chemical manufacturing processes they were assumed to be small in the context of climate change. In the work described here| climate change impacts from the energy used to produce a number of common refrigerant fluids are evaluated. These impacts are compared with the potential impact on global warming from the other components of TEWI: use and disposal of the refrigerants| including direct release into the environment. It is shown that the implications for climate change of the production of traditional refrigerants like ammonia| hydrocarbons or CFC-12 and new refrigerating fluids| such as HFC-134a| are truly insignificant in comparison with other stages of the life cycle of a refrigerator and have no role in TEWI. 2361,1998,5,4,The date of last large eruption of Changbaishan-Tianchi volcano and its significance,The systematical C-14 age of a large gagatite| which has been found in the pumiceous airfall deposits of the last large eruption of Changbaishan-Tianchi volcano| is dared from its centre to its edge. By fitting the C-14 age with the high precise calibrated curve of tree ring| it is concluded that the date of the last large eruption is (1215 +/- 15) AD. In addition| the climatic effects of that large eruption are also discussed| pointing out that the last large eruption probably corresponds to the sulfuric acid peak at (1227 +/- 2) AD in GISP2 Greenland ice core. 4561,1998,2,4,The effect of deforestation on ground surface temperatures,Recorded ground surface temperatures (GSTs) over a period of a year at closely spaced sites in a temperate area (almost no snow or ground freezing) show that forested sites and one with a high water table have colder average temperatures relative to other terrains. At sites in southern British Columbia where trees have been logged and in the southern Yukon where they were burned down by a forest fire| the ground surface temperature increased at the time of deforestation. Borehole temperatures are used to show this since no GSTs were recorded. At these sites there has been no subsequent reforestation| and the ground surface temperature has remained nearly constant since deforestation. The times since deforestation range from 5 to 52 years| and the average increase in ground surface temperature is 1.8 K on northern Vancouver island and 1.2 K in the southern Yukon. The heat required for transpiration in a forest is about 10% of the net radiative heat flux at the ground surface. If this amount of heat is surplus due to deforestation and if the earth is considered to radiate heat like a black body| then the expected increase in the GST is of the order of 1 K. (C) 1998 Elsevier Science B.V. All rights reserved. 4488,1998,2,4,The effects of elevated winter temperature and sub-lethal pollutants (low pH| elevated ammonia) on protein turnover in the gill and liver of rainbow trout (Oncorhynchus mykiss),Appetite| growth| and protein turnover (synthesis| growth and degradation) of liver and gills were measured in juvenile rainbow trout (Oncorhynchus mykiss) fed to satiation| and exposed for 90 days to elevated winter temperatures (+2 degrees C above ambient) and either low pH (5.2) in softwater or 70 mu M total ammonia (T-Amm) in hardwater. All fish increased in weight during the experiments| but those exposed to +2 degrees C grew significantly more than those at ambient temperature due to a stimulation of appetite. During the relatively constant temperature of the first 75 days| +2 degrees C caused a significant increase in the rates of protein synthesis and degradation in the liver of hardwater-acclimated fish| as a result of an increase in RNA translational efficiency (K-RNA) The elevated temperature also induced an increase in gill protein synthesis in softwater-acclimated fish but in this case the underlying mechanism was an increase in C-s| the capacity for protein synthesis (RNA:protein) rather than in K-RNA. The addition of 70 mu M T-Amm had no effect on protein turnover in either liver or gills of hardwater-acclimated fish. Low pH inhibited protein growth in the liver of softwater-acclimated fish at day 90 under both temperature regimes. This inhibition was effected via a decrease in protein synthesis at control temperature but via an increase in protein degradation when the fish were exposed to both low pH and +2 degrees C. From these results we conclude that a simulated global warming scenario has potentially beneficial rather than detrimental effects on protein turnover and growth of freshwater fish during winter. 2352,1998,4,4,The effects of global temperature change on rice leaf blast epidemics: a simulation study in three agroecological zones,A combined simulation model (CERES-Rice coupled with BLASTSIM) was used to study the effects of global temperature change on rice leaf blast epidemics in several agroecological zones in Asia. At least five years of historical daily weather data were collected from each of 53 locations in five Asian countries (Japan| Korea| China| Thailand and Philippines). Two weather generators| WGEN and WMAK| from the Decision Support System for Agrotechnology Transfer (DSSAT)| were utilized to produce estimated daily weather data for each location. Thirty years of daily weather data produced by one of the generators for each location were used as input to the combined model to simulate blast epidemics for each temperature change. Maximum blast severity and the area under the disease progress curve (AUDPC) caused by leaf blast resulted from 30-yr simulations were statistically analyzed for each temperature change and for each location. Simulations suggest that temperature changes had significant effects on disease development at most locations. However| the effect varied in different agroecological zones. In the cool subtropics such as Japan and northern China| elevation of temperature above normal temperature resulted in more severe blast epidemics. In warm/cool humid subtropics| elevation of temperature caused significantly less blast epidemics. However| lower temperature caused insignificant difference in disease epidemics compared with that in normal temperature. Conditions in the humid tropics were opposite to those in cool areas| where daily temperature changes by -1 degrees C and -3 degrees C resulted in significantly more severe blast epidemics| and temperature changes by +1 degrees C and +3 degrees C caused less severe blast. Scenarios showing blast intensity as affected by temperature change in different agroecological zones were generated with a geographic information system (GIS). (C) 1998 Elsevier Science B.V. 4480,1998,2,2,The greenhouse gas-induced climate change over the Indian subcontinent as projected by general circulation model experiments,In order to assess the climatic impacts of increasing greenhouse gas concentrations in the atmosphere on the Indian subcontinent with a fair degree of confidence| we recently undertook an intercomparison study of a range of general circulation modelling experiments for which the data were available to us. This study (Lal et al.| 1998) reported our findings on the performance of each of the 17 global climate model experiments in simulating the present-day regional climatology over the Indian subcontinent. The analysis suggested that a few global climate models performed exceptionally well in their control simulation to represent the observed present-day climatological patterns over the region of interest. In this paper| we focus on the development of plausible climate change scenario for the Indian subcontinent based on selected model simulations with enhanced greenhouse gas forcings. Our analysis suggests that| for a 1 degrees C rise in mean annual global temperature| the seasonal surface air temperature increase over the Indian subcontinent is likely to range from 0.7 degrees C to 1.1 degrees C during winter and 0.6 degrees C to 1.0 degrees C during summer. The increase in summer precipitation associated with the projected scaled rise in surface temperature could be between 1.2% to 4.5 %. The model results do not suggest any significant change in the winter precipitation over the region. Taking into account the suggested range of climate sensitivity as well as the range of future greenhouse gas-induced global warming in selected general circulation model experiments| a plausible climate change scenario for the Indian subcontinent is developed for the years 2030 and 2070. A rise in mean winter surface air temperature of between 0.4 degrees C to 1.7 degrees C by the year 2030 and between 0.7 degrees C to 3.4 degrees C by the year 2070 is projected. During the summer season| the temperature rise is expected to range between 0.3 degrees C to 1.4 degrees C by the year 2030 and 0.6 degrees C to 3.1 degrees C by the year 2070. The study suggests intense spells of summer monsoon rainfall over the Indian subcontinent due to enhanced convective activity in a warmer atmosphere. 4614,1998,2,3,The impact of current and possibly future sea surface temperature anomalies on the frequency of Atlantic hurricanes,A brief summary of the current capabilities of a high resolution global numerical prediction model towards resolving the life cycles of hurricanes is first presented. Next| we illustrate the results of season long integrations for the years 1987 and 1988 using the observed sea surface temperature (SST) anomalies over the global oceans. The model being used here is the FSU atmospheric global spectral model at the horizontal resolution of T42 and with 16 vertical layers. The main emphasis of this study is on hurricane tracks for these and for global warming experiments. The global warming scenarios were modeled using doubled CO2 and enhanced SST anomalies. The model being atmospheric does not simulate the ocean| and SST anomalies need to be prescribed. It is assumed in these experiments that the SST anomalies of the doubled CO2 world appear similar to those of the current period but that they are slightly warmer over the global tropics. That is determined using a simple proportionality relationship requiring an enhancement of the global mean SST anomaly over the tropics. Such an enhancement of the SST anomaly of an El Nino year 1987 amplifies the SST anomaly for the El Nino of the double CO2 atmosphere somewhat. The La Nina SST anomalies were similarly enhanced for the double CO2 atmosphere during 1988. These hurricane season experiments cover the period June through October for the respective years. It was necessary to define the thresholds for a model simulated hurricane; given such a definition we have compared first the tracks and frequency of storms based on the present day CO2 simulations with the observed storms for 1987 and 1988. Those comparisons were noted to be very close to the observed numbers of the storms. The doubled CO2 storms show a significant enhancement of the frequency of storms for the La Nina periods| however there was no noticeable change for the El Nino experiments. We have also run an experiment using the SST anomalies from a triple CO2 climate run made at the Max Planck Institut at Hamburg| This experiment simulated some 7 hurricanes over the Atlantic Ocean. The intensity of hurricanes| inferred from maximum winds at 850 mb| show that on the average the storms are slightly more intense for the double CO2 experiments compared to the storms simulated from current CO2 conditions. The triple CO2 storms were slightly stronger in this entire series of experiments. 2377,1998,2,4,The impact of elevated CO2 on plant-herbivore interactions: experimental evidence of moderating effects at the community level,Surprisingly little research has been published on the responses to elevated [CO2] at the community level| where herbivores can select their preferred food. We investigated the combined effects of atmospheric [CO2] and herbivory on synthesised plant communities growing on soils of different fertility. Factorial combinations of two [CO2] (350 or 700 mu l l(-1))| two fertility (fertilised or non-fertilised)| and two herbivory (herbivores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass| foliar nitrogen and soluble tannin concentration| aphid fecundity| and snail growth| fecundity| and feeding preferences over one growing season. Elevated [CO2] did not have a significant impact on(1)the combined biomass of fast-growing or slow-growing plants| (2) herbivore feeding preferences| or (3) herbivore fitness. There was| however| a significant biomass increase of Carex flacca (which represented in all cases less than 5% of total live biomass)| and some chemical changes in unpalatable plants under elevated [CO2]. The herbivory treatment significantly increased the biomass of slow-growing plants over fast-growing plants| whereas fertilisation significantly increased the abundance of fast-growing plants over slow-growing plants. Predictions on the effects of elevated [CO2] based on published single-species experiments were not supported by the results of this microcosm study. 4675,1998,2,4,The influence of drought and natural re-wetting on nitrogen dynamics in a coniferous ecosystem in Ireland,A field drought-rewetting treatment was artificially imposed in a Picea abies (L.) Karst. stand in each of four consecutive years (1992-1995) by means of a roof installed beneath the canopy. It was removed each year to allow natural rainfall rewet the soil in order to test Ulrich's (1980) 'Acidification pulse' hypothesis| viz. that rewetting a soil subsequent to drought results in net nitrification and acidification. NH4+ concentrations in the Drought plot humus water increased substantially following drought and rewetting in 1992 (3754 mu mol(c) L-1| i.e. 36% total cations)| to a lesser degree in 1994 and 1995| and were accompanied by elevated pH values tin the range pH 5.7 to 6.3)| whereas NH4+ levels and pH values (between pH 3.7 and 3.8) were unaffected during these times in the Control plot humus water. High NO3- concentrations were observed in the Drought humus water immediately after drought and rewetting in 1992| whereas in 1994 and 1995 there was a time-lag during which nitrate concentrations increased steadily. In contrast| NH4+ and NO3- concentrations were consistently low at all depths in the mineral soil waters of both the Drought and Control plots throughout the years of the experiment. Likewise| pH values were unaffected in the mineral soil water at these times| suggesting that microbiological activity and nitrification was largely confined to the O horizon at this site. This research then| indicates that Ulrich's hypothesis was not applicable in the Ballyhooly site. Ammonification dominated over nitrification after drought and rewetting under current Irish climatic conditions. However| under conditions of increased air temperatures| as in the 'global warming' scenario| the potential for enhanced nitrification and consequent acidification and leaching of NO3- produced after drought and rewetting may exist at Ballyhooly. 2314,1998,2,4,The potential of SPOT-Vegetation data for fire scar detection in boreal forests,Boreal forests cover 10% of the land surface and experience wide ranges of temperature and precipitation. In many parts of the boreal zone| fire drives vegetation succession| landscape dynamics and carbon cycling. Global climate change may affect the frequency and size of wildfires and alter the rate of carbon release into the atmosphere. Monitoring changes in fire frequency are therefore vital for forest management and predicting climate change impacts. The continuity of remotely sensed data| combined with the extent and remoteness of the boreal ecosystem make Earth observation an important tool for fire monitoring. This Letter examines the applicability of data from SPOT-Vegetation for regional fire monitoring in the context of other available Earth observation instruments. We show that use of the middle-infrared waveband gives a more reliable indication of fire scars than vegetation index approaches currently employed. 4599,1998,2,4,The role of ocean in the response of tropical climatology to global warming: The west-east SST contrast,A theory of tropical climatology is used to study the role of ocean in the response of tropical climatology to global warming. Special emphasis is given to the response of the west-east SST contrast along the equator. The transient response of tropical sea surface temperature to a global warming is shown to have two distinctive stages: a fast surface adjustment stage of years and a slow thermocline adjustment stage of decades. Under a global warming heat flux that does not vary much in space| the initial response is always an enhanced west-east SST contrast. The final equilibrium response| however| depends on the effective latitudinal differential heating. The west-east SST contrast increases for an enhanced latitudinal differential heating| and vise versa. 4551,1998,2,4,The significance of air pollution in sugar maple decline,Sugar maple decline has been a prominent issue since the late 1970s| when large areas of Quebec and Ontario were affected by this phenomenon. Links have been established between decline and insect damage| airborne heavy metals and acidic pollutants| and drought. Research has also indicated that global warming and resulting climactic changes may also cause decline. The phenomenon can be partially alleviated by proper management of sugar bushes. Although sugar maple decline has been on the wane over recent years| it may pose a serious problem in the future. 2371,1998,3,2,The strategies of abating emission of Co-2 and nuclear energy development in China,In China| annual coal consumption accounts for the first place all over the world in order to meet the high speed development of economy and improvement of the people's living quality. CO(2)emission from coal fire is a main contributor to the climate change. We must abate CO(2)emission besides developing economy for mitigating the global climate change. In the feasible countermeasure to reduce CO2 emission| which includes improving energy efficiency and developing alternative energy| developing nuclear energy is an important one. (C) 1997 Published by Elsevier Science Ltd. 4520,1998,3,3,The urgent need to internalize CO2 emission costs,Despite growing manifestations of global warming and the commitment of most nations to move towards reducing greenhouse gas (GHG) emissions| a simple device that can be effective in reducing GHG emissions continues to be overlooked or even rejected. This is to acknowledge the fact that carbon emissions inflict global costs that are not borne by emitters. This paper advocates that all activities emitting or saving cat-ban emissions should internalize the carbon cost inflicted or avoided by new projects involving CO2. Considering the current wide range of carbon cost estimates| the paper recommends that a two-stage approach be adopted. Firstly| incorporate carbon costs in project analysis only theoretically in order to differentiate objectively among alternative designs involving carbon emissions of varying degrees. Different estimates of the costs of a ton of carbon would be used in order to test the sensitivity of rates of return to alternative carbon castings. While this process would have the effect of screening the allocation of scarce investment funds among projects that affect global warming in different degrees| it should be viewed as only a first step. Secondly| we advocate a rigorous process of passing through estimated carbon costs to the ultimate users of the services of carbon-emitting projects and processes. It is this ultimate process that will secure the urgently needed transition from the current dependence on fossil fuels to more benign sources of energy that would reduce climate-change risks. Since the time available is limited| the paper points out the urgency of these proposals that are crucial for sustainability. (C) 1998 Published by Elsevier Science B.V. All rights reserved. 4491,1998,2,3,The utilization of bryophytes in bioclimatic modeling: Predicted northward migration of peatlands in the Mackenzie River Basin| Canada| as a result of global warming,A bioclimatic model based on bryophyte species distribution and abundance relative to climate was coupled with climatic and geographical data obtained from Leemans and Cramer (1991) and the Canadian Climate Center (CCC) General Circulation model (GGM) at 1XCO(2) in order to reconstruct the present geographical distribution of seven peatland types in the Mackenzie River Basin. The geographical distribution of 195 peatlands previously identified by type were used to test the validity of the reconstructions. The rest revealed that the reconstruction using data from Leemans and Cramer was more accurate than the reconstruction using the CCC GCM data. For this reason| the CCC 1XCO(2) data was subtracted from the CCC 2XCO(2) climatic data to produce an anomalies data set which was then added to the Leemans and Granter data to project the distribution of the seven types of peatlands at 2XCO(2). Results of this prediction were then compared to predictions using 2XCO(2) data obtained from the Geophysics Fluid Dynamics Laboratory (GFDL) GCM. The position. of the southern limits of peatland distribution was compared to past distributions resulting from a warming period in the early to mid Holocene. Results of the predictions for the two climate change scenarios indicated a northward migration of the southern boundary of peatland ecosystems of approximately 780 km in the central portion of the Mackenzie River Basin. The model also predicted that Mid-Boreal peatlands would be located along a diagonal running from southeast to northwest from 60 degrees longitude to an area just south of the Mackenzie Delta far both scenarios. High-Boreal and Subarctic peatlands were located to the north of the diagonal| while Low-Boreal peatlands were located to the south. However| the CCC anomalies + Leemans and Cramer predictions did not clearly define the Low-Boreal since Low-Boreal indicators were only located in the Cordilleran Ecological Province. Ecological diversity is anticipated to be maintained in the peatlands because all types were predicted to be found in the Basin at 2XCO(2) but at different locations. Comparisons between the predicted position of the southern limits of peatland distribution and that during the early to mid Holocene indicate that the model's predictions were reasonable. 4554,1998,3,4,Theoretical evaluation of carbon dioxide refrigeration cycle,Concerns of ozone depletion and global warming call for investigation of natural refrigerants. in this study the performance potential of the carbon dioxide refrigeration cycle is investigated theoretically. For this purpose| two cycle simulation models were developed. One is an Evans-Perkins cycle model for R-22| and the other is a transcritical cycle model for CO2. By using these models| the CO2 refrigeration cycle and heat exchangers for the CO2 refrigeration cycle were optimized. The water chilling and lap water heating performances of CO2 were compared to those of R-22. The thermophysical properties of CO2 and the proper heat exchanger design appropriate to CO2 offer the opportunity of reducing heat exchanger size and mass for tap water heating applications.
4607,1998,2,2,Thermal limits and ocean migrations of sockeye salmon (Oncorhynchus nerka): long-term consequences of global warming,Ocean surveys show that extremely sharp thermal boundaries have limited the distribution of sockeye salmon (Oncorhynchus nerka) in the Pacific Ocean and adjacent seas over the past 40 years. These limits are expressed as a step function| with the temperature defining the position of the thermal limit varying between months in an annual cycle. The sharpness of the edge| the different temperatures that define the position of the edge in different months of the year| and the subtle variations in temperature with area or decade for a given month probably all occur because temperature-dependent metabolic rates exceed energy intake from feeding over large regions of otherwise acceptable habitat in the North Pacific. At current rates of greenhouse gas emissions| predicted temperature increases under a doubled CO2 climate are large enough to shift the position of the thermal limits into the Bering Sea by the middle of the next century. Such an increase would potentially exclude sockeye salmon from the entire Pacific Ocean and severely restrict the overall area of the marine environment that would support growth. 4477,1998,2,3,Thermodynamic model of global warming,A thermodynamic model of global warming (greenhouse effect) has been developed to calculate the rise in global temperature and sea level due to increasing concentration of atmospheric greenhouse gases relative to the pre-industrial era (approximate to 1800 AD). The growth rate of various greenhouse gases in future decades has been taken as per IPCC-1996 technical data. Accordingly| the mean global temperature is projected to increase by about 1.9 K during 1800-2100 AD out of which 1.3 K will be in the next 100 years (i.e. twenty first century)| Also| the mean sea level is projected to rise by about 86 cm during 1800 to 2100 AD out of which 60 cm will be in the next 100 years. It is the thermal expansion of oceans which accounts for about 95% of the rise in sea level and the rest comes from the melting of ice in greenland| glaciers and mountain caps. 4594,1998,4,3,Trace-gas greenhouse effect and global warming - Underlying principles and outstanding issues - Volvo Environmental Prize Lecture - 1997,This paper describes the developments that transformed the global warming problem from that arising solely from CO2 increase to the trace-gas greenhouse effect problem in which several non-CO2 gases| CFCs| CH4| N2O| O-3 and others contribute as much as CO2. Observed trace-gas increases| including CO2 increase| since the mid-19th century have enhanced the atmospheric greenhouse effect| G(a)| (approximate to 130 +/- 5 W m(-2)) by about 2%. Without other competing factors| this heating should have committed the planet to a warming of about 1 to 1.5 K. The added radiative energy is maximum in the low latitudes and about a factor of two smaller in the polar regions. The largest effect of the warming is increased back radiation at the surface by as much as 6 to 8 W m(-2) per degree warming. Not all of this increased energy is balanced by surface emission; evaporation (and hence precipitation) increases to restore surface energy balance| by as much as 2 to 4% per degree warming. The increase in evaporation along with the increase in saturation vapor pressure of the warmer troposphere| contributes through the atmospheric dynamics to an increase in water vapor. This water vapor feedback enhances G(a) by another 1% per degree warming. Our ability to predict regional and transient effects| depends critically on resolving a number of outstanding issues| including: i) Aerosol and stratospheric ozone effects; ii) Response of the tropical convective-cirrus clouds| the extra-tropical storm-track systems and persistent coastal stratus to both global warming and to regional emissions of aerosols; iii) The causes of excess solar absorption in clouds; and iv) Upper troposphere water vapor feedback effects. 2344,1998,3,4,Trade-offs in refrigerant selections: past| present| and future,Recent attention to depletion of stratospheric ozone| by chemicals containing bromine and chlorine| resulted in an international accord to halt their production. The most widely used refrigerants are among them. Chemical and equipment manufacturers mounted aggressive research and development programs to introduce alternative and transition refrigerants| associated lubricants and desiccants| and redesigned equipment. The already difficult criteria became even more complex| with subsequent linkage of chemical emissions from human activities to global climate change. The very successful response to protect the ozone layer has led some regulators and users to assume that ideal substitutes will be found. Such chemicals should be free of all environmental and safety concerns| be chemically and thermally stable| and perform efficiently. The analyses presented in this paper demonstrate that the outlook for discovery or synthesis of ideal refrigerants is extremely unlikely. Trade-offs among desired objectives| therefore| are necessary to achieve balanced solutions. The paper also shows that fragmented regulation of the chemicals involved. to address individual issues| jeopardizes the prospect of solving subsequently addressed problems. The paper reviews the history of refrigerants| their roles in ozone depletion and global climate change| and necessary trade-offs in refrigerant selections. (C) 1998 Elsevier Science Ltd and IIR. All rights reserved. 4560,1998,4,3,Transient CO2 experiment using the ARPEGE/OPAICE non flux corrected coupled model,A transient CO2 experiment using the ARPEGE/ OPAICE coupled general circulation model with no flux correction has been performed at CERFACS. Despite a warm initial climate drift| the main features of the observed climate are reasonably captured in the control simulation. In particular| the simulated oceanic circulation is satisfactory. The transient CO2 simulation shows a global warming of 1.6 degrees C in surface air temperature at the time of CO2 doubling. This value and the main geographical patterns of climate change are in agreement with previous studies using either flux corrected or non flux corrected models. The absence of flux correction does not prevent the too strong atmospheric water fluxes to produce an unrealistic freshening of the upper layer of the Northern North Atlantic which leads to a reduction of the thermohaline circulation in the control simulation. As a consequence| the weakening of the thermohaline circulation in response to the anthropogenic radiative forcing is less than expected. 2343,1998,4,4,Tree-limits and montane forests in the Swedish Scandes: Sensitive biomonitors of climate change and variability,The elevational tree-limit constitutes an ideal and sensitive proxy indicator of climate change and variability| i.e. an essential part of monitoring systems focusing on global climate change. That contention is purported by multi-scale records and reconstructions of changes in altitudinal tree-limits and northern boreal forests. Climatically forced trends in their position| structure and composition have occurred at all temporal scales throughout the Holocene. A progressive elevational descent of Pinus sylvestris tree-limit since the earliest Holocene| concurs with the deterministic theory of millennial climate forcing by changes in the Earth's orbital parameters. The successively less seasonal climate with cooler| more humid summers and winters with increasing snow cover has preconditioned the emergence of a subalpine birch forest belt during the past ca. 7000 yrs BP as well as the growing gee-ecological prominence of Picea abies. Superimposed on this longterm trend| climatic anomalies of shorter duration have been inferred from the tree-limit chronology. Some exceptionally warm and stable centuries| with high tree-limits and dense montane forests occurred during the Medieval period. Thereafter| the Little Ice Age prevailed until the late 19th century. Northern and high-elevation ecosystems were profoundly stressed| disturbed and destabilized by cold| windy and highly variable climate conditions. An episode of warmer climate during the first half of the present century imposed some recovery of structures decayed by the Little Ice Age. However| tree-limits and high-elevation forests were far from restored to their medieval levels. During the past 4-5 decades| a more martime and slightly cooler climate has been instrumentally recorded. High-elevation arboreal vegetation has responded retrogressively by defoliation| retarded growth| ceasing regeneration and locally some tree-limit retraction. Neoglacial processes have been resumed| e.g. dieback of subalpine/alpine dwarf shrub heaths| followed by deflation of humus and surface mineral soils. These processes are readily monitored in a unique regional network| with baseline data since the early 20th century. 2365,1998,4,4,Tropical cyclones and global climate change: A post-IPCC assessment,The very limited instrumental record makes extensive analyses of the natural variability of global tropical cyclone activities difficult in most of the tropical cyclone basins. However| in the two regions where reasonably reliable records exist (the North Atlantic and the western North Pacific)| substantial multidecadal variability (particularly for intense Atlantic hurricanes) is found| but there is no clear evidence of long-term trends. Efforts have been initiated to use geological and geomorphological records and analysis of oxygen isotope ratios in rainfall recorded in cave stalactites to establish a paleoclimate of tropical cyclones| but these have not yet produced definitive results. Recent thermodynamical estimation of the maximum potential intensities (MPI) of tropical cyclones shows good agreement with observations. Although there are some uncertainties in these MPI approaches| such as their sensitivity to variations in parameters and failure to include some potentially important interactions such as ocean spray feedbacks| the response of upper-oceanic thermal structure| and eye and eyewall dynamics| they do appear to be an objective tool with which to predict present and future maxima of tropical cyclone intensity. Recent studies indicate the MPI of cyclones will remain the same or undergo a modest increase of up to 10%-20%. These predicted changes are small compared with the observed natural variations and fall within the uncertainty range in current studies. Furthermore| the known omissions (ocean spray| momentum restriction| and possibly also surface to 300-hPa lapse rate changes) could all operate to mitigate the predicted intensification. A strong caveat must be placed on analysis of results from current GCM simulations of the "tropical-cyclone-like" vortices. Their realism| and hence prediction skill (and also that of "embedded" mesoscale models)| is greatly limited by the coarse resolution of current GCMs and the failure to capture environmental factors that govern cyclone intensity. Little| therefore| can be said about the potential changes of the distribution of intensities as opposed to maximum achievable intensity. Current knowledge and available techniques are too rudimentary for quantitative indications of potential changes in tropical cyclone frequency. The broad geographic regions of cyclogenesis and therefore also the regions affected by tropical cyclones are not expected to change significantly. It is emphasized that the popular belief that the region of cyclogenesis will expand with the 26 degrees C SST isotherm is a fallacy. The very modest available evidence points to an expectation of little or no change in global frequency. Regional and local frequencies could change substantially in either direction| because of the dependence of cyclone genesis and track on other phenomena (e.g.| ENSO) that are not yet predictable. Greatly improved skills from coupled global ocean-atmosphere models are required before improved predictions are possible. 2320,1998,3,4,Tropical forest fragmentation and greenhouse gas emissions,Rainforest fragments in central Amazonia have been found to experience a marked loss of above-ground biomass caused by sharply increased rates of tree mortality and damage near fragment margins. These findings suggest that fragmentation of tropical forests is likely to increase emissions of CO2 and other greenhouse gases above and beyond that caused by deforestation per se. We estimated committed carbon emissions from deforestation and fragmentation in Amazonia| using three simulated models of landscape change: a 'Rondonia scenario|' which mimicked settlement schemes of small farmers in the southern Amazon; a 'Para scenario|' which imitated large cattle ranches in the eastern Amazon; and a 'random scenario|' in which forest tracts were cleared randomly. Estimates of carbon emissions for specific landscapes were from 0.3 to 42% too low| depending on the amount and spatial pattern of clearing| when based solely on deforestation. Because they created irregular habitat edges or many forest perforations which increased tree mortality| the Rondonia and random-clearing scenarios produced 2-5 times more fragmentation-induced carbon emissions than did the Para scenario| for any given level of clearing. Using current estimates of forest conversion| our simulations suggest that committed carbon emissions from forest fragmentation alone will range from 3.0 to 15.6 million t/year in the Brazilian Amazon| and from 22 to 149 million t/year for tropical forests globally. (C) 1998 Elsevier Science B.V. 4533,1998,3,3,Two model analyses of the urban structure of minimal transportation energy consumption,The transportation sector needs to reduce fuel consumption to deal with global warming because it depends on fossil fuels strongly and it seems to be difficult to substitute other fuels. This study aims at investigating an optimal land use in urban areas from the viewpoint of reducing energy consumption for transportation. For this purpose| the authors developed two kinds of models. One minimizes the total trip length under the condition of constant congestion. The other minimizes the fuel consumption directly where congestion is taken into account endogenously. The optimal structures calculated numerically illustrate that business areas are located around the center of a city while residential areas are on the suburbs| which is similar to the actual land use observed generally. These results are compared with the land use of the central business district (CBD) in Tokyo. (C) 1998 Elsevier Science Ltd. All rights reserved. 2362,1998,4,4,Uncertainty| complexity and concepts of good science in climate change modelling: Are GCMs the best tools?,In this paper we explore the dominant position of a particular style of scientific modelling in the provision of policy-relevant scientific knowledge on future climate change. We describe how the apical position of General Circulation Models (GCMs) appears to follow 'logically' both from conventional understandings of scientific representation and the use of knowledge| so acquired| in decision-making. We argue| however| that both of these particular understandings are contestable. In addition to questioning their current policy-usefulness| we draw upon existing analyses of GCMs which discuss model trade-offs| errors| and the effects of parameterisations| to raise questions about the validity of the conception of complexity in conventional accounts. An alternative approach to modelling| incorporating concepts of uncertainty| is discussed| and an illustrative example given for the case of the global carbon cycle. In then addressing the question of how GCMs have come to occupy their dominant position| we argue that the development of global climate change science and global environmental 'management' frameworks occurs concurrently and in a mutually supportive fashion| so uniting GCMs and environmental policy developments in certain industrialised nations and international organisations. The more basic questions about what kinds of commitments to theories of knowledge underpin different models of 'complexity' as a normative principle of 'good science' are concealed in this mutual reinforcement. Additionally| a rather technocratic policy orientation to climate change may be supported by such science| even though it involves political choices which deserve to be more widely debated. 4562,1998,3,4,Use of 2H-heptafluoropropane| 1-iodoheptafluoropropane| and 2-iodoheptafluoropropane for a high aspect ratio via etch in a high density plasma etch tool,An issue currently facing the semiconductor industry is the use and emission of perfluorocompounds (PFCs)| gases which are believed to contribute to global warming| in a number of plasma processes used in integrated circuit manufacture| including wafer patterning. Several approaches to reducing emissions of these compounds are being considered| namely abatement| recapture/recovery| process optimization| as well as the development of alternative chemistries as PFC substitutes. The authors present here the results of an effort to test several alternatives in a silicon dioxide etch application (high aspect ratio via etch). 2H-heptafluoropropane| 1-iodoheptafluoropropane| and 2-iodoheptafluoropropane| were tested in an Applied Materials Centura 5300 high density plasma etch tool. Fourier transform infrared spectroscopy was used to analyze the process effluent. The process performance and emissions of the alternative etchants were compared to those of a standard chemistry on the Centura 5300 etch tool. (C) 1998 American Vacuum Society. [S0734-2101(98)02904-2]. 4489,1998,3,4,Use of novel hydrofluorocarbon and iodofluorocarbon chemistries for a high aspect ratio via etch in a high density plasma etch tool,This paper presents the results of an effort to test several novel chemistries for use as replacements for perfluoro-compounds in dielectric etch processes. Chemistries belonging to the hydrofluorocarbon and iodofluorocarbon families| namely| 2H-heptafluoropropane (CF3-CFH-CF3)| iodotrifluoromethane (CF3I)| 1-iodoheptafluoropropane (CF2I-CF2-CF3)| and 2-iodoheptafluoropropane (CF3-3CFI-CF3) were tested in an Applied Materials Centura 5300 HDP etch tool| using a high aspect ratio silicon dioxide via etch application as the test vehicle. Designed experiment methodology was used in the evaluation. Effluent was analyzed using Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The performance of the alternative etchants in a high aspect ratio via etch process was compared to that of a standard chemistry on the Centura 5300 etch tool. Significant reductions in global warming emissions| relative to a perfluorinated baseline process| were found to be attainable with the alternative chemistries. 2309,1998,2,4,Variability in seedling water status during drought within a Quercus ilex subsp. ballota population| and its relation to seedling morphology,Differences in morphology| growth and plant water status during drought were studied in greenhouse-grown Quercus ilex subsp. ballota seedlings produced by different mother trees occurring in a savannah-like forest (locally named dehesa) in southern Spain. There were significant differences among mother trees in the biomass of their seeds (mother tree level accounted for 62% of total variance in this trait)| in the percentage of seedlings that emerged and in the time of shoot emergence. The progeny that had high emergence rates (80-90%) also had shea emergence times while the opposite was true for the progeny that had low (43%) and intermediate (70%) emergence rates. Acorn biomass covaried significantly with seedling total biomass and with the biomass of different parts of the seedlings| but not with the partitioning of biomass among roots and shoots (root/shoot ratio) nor to morphological seedling traits such as shoot height| total leaf area| average leaf size| specific leaf area (SLA) and leaf number. All these traits varied significantly among the seedlings produced by different mother trees. The conductance to water vapour (gi|) of the foliage of the seedlings also varied significantly among mother trees and was dependent on the root/shoot ratio as on the total leaf area of the seedlings| but not on the total seedling biomass. One of the six trees that were studied produced seedlings which had a significantly higher root/shoot ratio| smaller leaf area| smaller leaves| higher specific leaf area and shorter stems than the seedlings produced by any other tree. In addition| the former set of seedlings had significantly higher g(1w) 15 and 30 days after drought| and higher leaf water content at the end of the experiment than the other seedlings. We discuss the value of using single seedling traits related to drought tolerance such as root/shoot ratio and leaf area in the framework of the restoration of savannah-like oak forest in the Mediterranean areas. We also discuss the functional implications of the diversity of genotypes within the oak populations in the framework of the global climate change. (C) 1998 Elsevier Science B.V. 4581,1998,2,4,Vectors vs humans in Australia - Who is on top down under? An update on vectorborne disease and research on vectors in Australia,Australia has a diversity of vectors and vector-borne human diseases. Mosquito-borne arboviruses are of greatest concern| but there are issues with other vector and pathogen systems. Mosquitoes were responsible for more than 35|000 cases of Ross River virus during 1991-1997. Barmah Forest virus is increasing nationwide| and unidentified bunyaviruses suspected of causing illness have been isolated. Cases of Murray Valley encephalitis have occurred in 14 of the past 20 years in northern Australia. Dengue is a continuing problem for northern Queensland| with various serotypes being active. Japanese encephalitis has appeared in the Torres Strait Islands and threatens mainland Australia. Although malaria is eradicated| almost 1|000 cases are imported annually and occasional cases of local transmission occur. With ticks| paralysis in children occurs annually in eastern Australia. Tick typhus (Queensland Tick Typhus - Rickettsia australis) occurs down the east coast| and (Flinders Island Spotted Fever - Rickett sia honei) in Bass Strait and probably Tasmania. Lyme disease is reported but its presence is controversial. Fleas were responsible for a recent outbreak of murine typhus (Rickettsia typhi) in Western Australia. Mites cause scrub typhus (Orientia tsutsugamushi)| and there was a recent fatality in the Northern Territory. Overall| resources for investigation and control of vector-borne disease have generally been meager. However| various avenues of basic and applied research have been pursued| and have included investigations into mosquito ecology| vector competence| disease epidemiology| and vector control. Disease surveillance programs vary between states| and mosquito control programs are organized and effective in only a few regions. There are concerns for import of vectors such as Aedes albopictus and export of pathogens such as Ross River virus; the former has occurred but the species has not become established| and the latter has occurred and has resulted in a major outbreak in the South Pacific. The predicted scenarios of increased temperature and rainfall with global warming are also causing concern for increases in vector-borne diseases| particularly the endemic arboviruses. Interest by health authorities is gravitating more towards epidemiological reporting and less towards public health action. In many respects| humans have much to do to get 'on top' of vectors and their pathogens 'down under' in Australia. 4642,1998,5,4,Vegetation-atmosphere interactions and their role in global warming during the latest Cretaceous,Forest vegetation has the ability to warm Recent climate by its effects on albedo and atmospheric water vapour| but the role of vegetation in warming climates of the geologic past is poorly understood. This study evaluates the role of forest vegetation in maintaining warm climates of the Late Cretaceous by (1) reconstructing global palaeovegetation for the latest Cretaceous (Maastrichtian); (2) modelling latest Cretaceous climate under unvegetated conditions and different distributions of palaeovegetation; and (3) comparing model output with a global database of palaeoclimatic indicators. Simulation of Maastrichtian climate with the land surface coded as bare soil produces high-latitude temperatures that are too cold to explain the documented palaeogeographic distribution of forest and woodland vegetation. In contrast| simulations that include forest vegetation at high latitudes show significantly warmer temperatures that are sufficient to explain the widespread geographic distribution of high-latitude deciduous forests. These warmer temperatures result from decreased albedo and feedbacks between the land surface and adjacent oceans. Prescribing a realistic distribution of palaeovegetation in model simulations produces the best agreement between simulated climate and the geologic record of palaeoclimatic indicators. Positive feedbacks between high-latitude forests| the atmosphere| and ocean contributed significantly to high-latitude warming during the latest Cretaceous| and imply that high-latitude forest vegetation was an important source of polar warmth during other warm periods of geologic history. 2338,1998,2,3,Vulnerability of island tropical montane cloud forests to climate change| with special reference to East Maui| Hawaii,Island tropical montane cloud forests may be among the most sensitive of the world's ecosystems to global climate change. Measurements in and above a montane cloud forest on East Maul| Hawaii| document steep microclimatic gradients. Relatively small climate-driven shifts in patterns of atmospheric circulation are likely to trigger major local changes in rainfall| cloud cover| and humidity. Increased interannual variability in precipitation and hurricane incidence would provide additional stresses on island biota that are highly vulnerable to disturbance-related invasion of nonnative species. Because of the exceptional sensitivity of these microclimates and forests to change| they may provide valuable 'listening posts' for detecting the onset of human-induced global climate change. 4628,1998,2,4,Vulnerability of rice and wheat yields in NW India to future changes in climate,Agricultural sector is one of the sensitive areas which would be influenced by the projected global warming and associated climate change. In spite of the uncertainties about the precise magnitude of climate change on regional scales| an assessment of the possible impacts of changes in key climatic elements on our agricultural resources is important for formulating response strategies. In this study| vulnerability of wheat and rice crops in northwest India to the projected climate change is examined. CERES wheat and rice models adopted for the study were validated for their ability to reproduce yields at the selected NW Indian stations. The sensitivity experiments with these models showed higher yields for both wheat and rice (28% and 15% respectively for a doubling of CO2) under elevated CO2 levels. A 3 degrees C (2 degrees C) rise in air temperature nearly cancels out the positive effect of elevated CO2 on the wheat (rice) yields. While the wheat crops are found to be sensitive to increase in maximum temperature| the rice crops are vulnerable to increase in minimum temperature. The combined effect of enhanced CO2 and imposed thermal stress on the wheat (rice) crop is 21% (4%) increase in yield for the irrigation schedule presently practised in the region. While the adverse impacts of likely water shortage on wheat crops would be minimised to a certain extent under elevated CO2 levels| they would largely be maintained for the rice crops resulting in about 20% net decline in rice yields. In general| acute water shortage conditions combined with the thermal stress should adversely affect both the wheat and more severely the rice productivity in NW India even under the positive effects of elevated CO2 in the future. (C) 1998 Elsevier Science B.V. 4646,1998,3,4,Will a global warming agreement be fair to developing countries?,Fairness| or equity| is a major concern of developing countries in negotiating a global agreement on greenhouse gas emission reductions. Operational versions of several equity concepts are analysed in the context of tradeable permits. We find that a global least-cost mitigation strategy is compatible with a variety of equity criteria. Moreover| the more cost-effective the global strategy| the greater the potential for North-South transfers. However| in many cases| the fairness of the final welfare outcomes differs significantly from the application of first principles for allocating permits. At the same time| several disparate equity criteria yield similar inter-country welfare outcomes. Still| some seemingly reasonable criteria are probably untenable from a political standpoint. 2375,1998,3,3,Will biomass be the environmentally friendly fuel of the future?,Many influential organisations foresee biomass playing a key role in a future| more sustainable| global energy supply matrix. Countries such as Austria| Brazil| Denmark| Finland| Sweden| India| the USA and the UK are actively encouraging the use of biomass for energy| and pushing forward the development of the necessary knowledge and technology for modern biomass energy systems. There is a growing consensus that renewable energy must progressively displace the use of fossil fuels| with fears of global climate change adding urgency to this need. Among the available types of renewable energy biomass is unique in its ability to provide solid| liquid and gaseous fuels which can be stored and transported. The potential resource for bioenergy is large| especially in forest-rich nations| in richer countries where there is a surplus of agricultural land| and in many low latitude countries where high biomass yields are possible. Therefore we expect biomass to be an important fuel of the future| but this cannot be taken for granted. The systems adopted must demonstrate clear environmental and social benefits relative to alternatives if the potential is to be realised. These benefits are not inherent to biomass energy| but depend on site- and fuel cycle-specific factors. Life-cycle analysis and evaluation of external costs are important means for assessing the social and environmental pros and cons of bioenergy systems. (C) 1998 Elsevier Science Ltd. All rights reserved. 4500,1998,3,4,World population and energy demand growth: the potential role of nuclear energy in an efficient world,The fertility rate for women and the related population growth rate| for numerous developing (transitional) countries| show a downward trend with increasing annual per capita energy use. On the assumption that such trends will continue| estimates are made for some simple cases of the energy demands required to stabilize the world's population in the period 2100 to 2150. An assessment is made of how these energy demands might be met| capitalizing as much as possible on the indigenous energy resources for each of the ten major regions of the world - North America| Latin America| Europe OECD| Former Soviet Union and Central and Eastern Europe| China| Pacific OECD| East Asia| South Asia| Africa| and the Middle East. Consideration is also given to the potential need to limit carbon emissions because of global warming concerns. The study highlights the crucial nature of energy efficiency improvements and the need to utilize all energy sources| including nuclear energy| if the world is to find a sustainable future with a much improved standard of living in the developing world. The deployment of more fission power can build upon the existing successes. The availability of fusion power will depend upon the pace of the development program and| in principle| fusion power deployment might start around the middle of the twenty first century. 2280,1999,2,4,A farmer's view of the Ricardian approach to measuring agricultural effects of climatic change,During the past few years two new methods| each based on the analogous region concept| have been developed to account for farmer adaptation in response to global climatic change. The first| called `Ricardian' by Mendelsohn| Nordhaus| and Shaw (1994)| econometrically estimates the impact of climatic and other variables on the value of farm real estate. Under some conditions| estimates of climate-induced changes in farm real estate capture first-round adaptations by farmers and represent the economic value of climatic change on agriculture. The second method| promulgated by Darwin et al. (1994) in the Future Agricultural Resources Model (FARM)| uses a geographic information system to empirically link climatically derived land classes with other inputs and agricultural outputs in an economic model of the world. FARM provides estimates of economic impacts that fully account for all responses by economic agents under global climate change as well as estimates of Ricardian rents. The primary objective of this analysis is to evaluate how well changes in Ricardian rents measure agricultural or other effects of climatic change after all economic agents around the world have responded. Results indicate that changes in Ricardian rents on agricultural land are poor quantitative| but good qualitative| measures of how global climatic change is likely to affect the welfare of agricultural landowners| if one recognizes that increases in Ricardian rents actually indicate losses in landowner welfare and vice versa. Results also indicate that regional changes in Ricardian rents on all land are good qualitative measures of changes in regional welfare. They are poor quantitative welfare measures because they systematically overestimate both benefits and losses and are on average upwardly biased because inflated benefits are larger than exaggerated losses. Results also indicate that| when based on existing land-use patterns| changes in Ricardian rents on all the world's land are poor quantitative and qualitative measures of changes in world welfare. Despite these shortcomings| changes in Ricardian rents can provide useful information when other measures are not available. In this analysis| for example| estimated changes in Ricardian rents on all land indicate that climatic change would likely have detrimental effects in Latin America and Africa| beneficial effects in the former Soviet Union| and either detrimental or beneficial impacts in eastern and northern Europe and western and southern Asia. This is consistent with previous studies showing that climatic change would likely have detrimental| beneficial| and mixed effects on economic welfare in| respectively| equatorial| high latitude| and temperate areas. Estimated changes in Ricardian rents also indicate that aggregating Africa| Latin America| the former Soviet Union| eastern and northern Europe| and western and southern Asia into one region causes FARM's economic model to generate upwardly biased changes in world welfare. Modified results from scenarios with moderately flexible land-use change and which account for current land-use patterns indicate that world welfare may increase if the average surface land temperature does not increase by more than 1.0 or 2.0 degrees C. If the average surface land temperature increases by 3.0 degrees C or more| however| then world welfare may decline. 5041,1999,2,3,A GCM investigation of global warming impacts relevant to tropical cyclone genesis,Two approaches that consider how greenhouse warming might impact the frequency of tropical cyclone (TC) genesis are explored. Results are based on GCM experiments with the q-flux version global climate model of the NASA/Goddard Institute for Space Studies (GISS); one set representing contemporary atmospheric concentrations of CO2| contrasting with the second set representing the global climate in double CO2 equilibrium. July-September means of climate parameters relevant to TC genesis are computed from the simulations and combined to formulate a seasonal genesis parameter (SGP)| as suggested in an empirical study by Gray (in Shaw| D.B. (ed.)| Meteorology Over the Tropical Oceans| 1979| pp. 155-218). The spatial distribution of the July-September SGP based on the control simulations is compared with the observed distribution and results using other models. The corresponding spatial distribution of the July-September SGP derived from the double CO2 simulations| when compared with the control results| projects a 50% increase in the genesis frequency of TC over the western North Atlantic/Gulf of Mexico basin| but 100-200% increases over the North Pacific Ocean. The increases| most of which are attributable to enhanced ocean temperatures| may be exaggerated| suggesting that the original SGP formulation requires tuning or other revisions. For example| it is noted that SGP computed from the NCEP 1982-1994 re-analysis climatology do not accurately reflect the known spatial distributions of TC genesis frequency. The second approach detects easterly waves over the eastern North Atlantic Ocean by spectral analysis of vorticity and wind component time trends| comparing wave activity in the control and double CO2 simulations. Results indicate a southward shift in future trajectories of easterly waves over West Africa and significant increases in their average amplitude as they cross the African coast and begin to traverse the Eastern Atlantic along 14 degrees N. Copyright (C) 1999 Royal Meteorological Society. 4923,1999,4,4,A heuristic model for the calculation of dinitogen and nitrous oxide flux from nitrogen-15-labeled soil,Very sensitive measurements of N-2 and N2O flux from soil are possible when gas evolved from N-15-labeled soil is analyzed by isotope ratio mass spectrometry| This approach is useful for studying the fate of nitrogen fertilizer and for studying soil microbial processes contributing to the atmospheric increase of nitrous oxide| a radiatively active trace gas that can contribute to global warming and ozone depletion. Most systems of equations that relate isotopic analysis to gas nut are sufficiently complex that certain limitations and potentials of the N-15 approach may be overlooked. We describe a graphical representation of labeled N-gas flux that illustrates the equations and encourages critical thinking regarding the implementation of related experiments| This model is used to interpret underestimation that occurs if flux derives from multiple pools of differing enrichment. A statistical derivation is presented for a previously published simulation of underestimation due to multiple pools. The same equations are applied to field data to explore whether temporal variation in soil nitrate enrichment is likely to cause significant underestimation. Two sampling strategies are proposed that may eliminate the assumption of pool uniformity| thereby eliminating a potential source of underestimation. 4968,1999,3,2,A highly-advanced solar house with solar thermal and sky radiation cooling,A unique energy-independent house ('HARBEMAN house'; HARmony BEtween Man And Nature) incorporating solar thermal| underground coolers| sky radiation cooling| photovoltaic electricity generation and rain-water collection was built in Sendai (latitude; 38 degrees 17'00 " north and longitude; 140 degrees 50'14 " east)| Japan during July| 1996. The average solar energy received on a horizontal surface there in January is 7900 kJ/m(2)/day. This paper reports the experimental results since September 1996 to date. The annual variations of water temperature in the underground main tank| heating/cooling/domestic hot water demands| collected and emitted heats by solar collector and sky radiator| were measured. The paper also clarifies the method of computer simulation results for the HARBEMAN house and its results compared with the annual experimental data. The proposed HARBEMAN house| which meets almost all its energy demands| including space heating and cooling| domestic hot water| electricity generated by photovoltaic cell and rainwater for standard Japanese homes. The proposed system has two operational modes: (i) a long-term thermal energy storage mode extending from September to March and (ii) a long-term cool storage mode extending from April to August. The system is intended to utilize as little energy as possible to collect and emit the heat. This paper also clarifies the primary energy consumption| the external costs (externalities) and the means for the reduction of carbon-dioxide (CO2) emissions. The primary-energy consumption and carbon-dioxide emissions of the proposed house are only one-tenth of those of the conventional standard house. Moreover| the thermal performance of this house will be compared with the results of the IEA solar low-energy house TASK 13. Finally| this paper validates the external costs of this house| which have been intensively discussed in recent years in European countries. The present energy-sufficient house will be attempting in 21st century to reduce carbon dioxide emissions| which will be one of the key factors for mitigating global warming. (C) 1999 Elsevier Science Ltd. All rights reserved. 5091,1999,4,2,A nonlinear dynamical perspective on climate prediction,A nonlinear dynamical perspective on climate prediction is outlined| based on a treatment of climate as the attractor of a nonlinear dynamical system D with distinct quasi-stationary regimes. The main application is toward anthropogenic climate change| considered as the response of D to a small-amplitude imposed forcing f. The primary features of this perspective can be summarized as follows. First| the response to f will be manifest primarily in terms of changes to the residence frequency associated with the quasi-stationary regimes. Second| the geographical structures of these regimes will be relatively insensitive to f. Third| the large-scale signal will be most strongly influenced by f in rather localized regions of space and time. In this perspective| the signal arising from f will be strongly dependent of D's natural variability. A theoretical framework for the perspective is developed based on a singular vector decomposition of D's tangent propagator. Evidence for the dyamical perspective is drawn from a number of observational and modeling studies of intraseasonal| interannual| and interdecadal variability| and from climate change integrations. It is claimed that the dynamical perspective might resolve the apparent discrepancy in global warming trends deduced from surface and free troposphere temperature measurements. A number of specific recommendations for the evaluation of climate models are put forward| based on the ideas developed in this paper. 2278,1999,4,3,A system to monitor climate change with epilithic lichens,The issue of biological monitoring of the local consequences of anticipated global climate change is considered for the Central Negev Highlands| Israel. Epilithic lichens are suggested as biological monitors. The proposed methodology of such monitoring consists of a sampling scheme| including lichen measurement along transects on flat calcareous rocks| and construction of a trend detection index (TDI). TDI is a sum of lichen species cover with coefficients chosen so as to ensure maximum ability to detect global climate trends. Coefficients have been estimated in a study of Lichens along an altitudinal gradient from 500 to 1000 m a.s.l. The gradient study demonstrated that the TDI index is performed better than other integrated indices. Recommendations on this system to monitor climate change with epilthic lichens are given. Measuring| for instance| a hundred transects in fifty plots (two transet per plot scheme) allows one to detect a climate-driven change in the epilithic lichen community corresponding to a 0.8 degrees C shift in annual mean temperature. Such resolution appears sufficient in view of global warming of 2.5 degrees C considered by the Intergovernmental Panel on Climate Change as a realistic prediction for the end of the next century. 5031,1999,3,4,A thermoacoustic Stirling heat engine,Electrical and mechanical power| together with other forms of useful work| are generated worldwide at a rate of about 10(12) watts| mostly using heat engines. The efficiency of such engines is limited by the laws of thermodynamics and by practical considerations such as the cost of building and operating them. Engines with high efficiency help to conserve fossil fuels and other natural resources| reducing global-warming emissions and pollutants. In practice| the highest efficiencies are obtained only in the most expensive| sophisticated engines| such as the turbines in central utility electrical plants. Here we demonstrate an inexpensive thermoacoustic engine that employs the inherently efficient Stirling cycle(1). The design is based on a simple acoustic apparatus with no moving parts. Our first small laboratory prototype| constructed using inexpensive hardware (steel pipes)| achieves an efficiency of 0.30| which exceeds the values of 0.10-0.25 attained in other heat engines(5|6) with no moving parts. Moreover| the efficiency of our prototype is comparable to that of the common internal combustion engine(2) (0.25-0.40) and piston-driven Stirling engines(3|4) 4 (0.20-0.38). 4937,1999,3,2,Addressing global warming and biodiversity through forest restoration and coastal wetlands creation,The Climate Challenge is a partnership between the Department of Energy and the electric utility industry to reduce| avoid| and sequester greenhouse gases. A portion of the initiative| the sequestration of greenhouse gases| is the focus of this presentation. Over 4 million acres of bottomland hardwood forests were cleared for agriculture in the Mississippi River Valley in the 1970s. Reestablishing these forests would improve depleted wildlife habitats| serve as wildlife corridors| increase biodiversity| and decrease soil erosion. Also| Louisiana is losing coastal wetlands at a rate of approximately 25 square miles/year. This coastal erosion is due to a number of factors and many efforts are currently underway to address the matter. One such effort is the use of material generated in the dredging of navigational canals; however| this material is low in nutrient value| making the regeneration of marsh grasses more difficult. In addition| bottomland hardwood forests and coastal wetland grasses are excellent 'carbon sinks' because they take carbon dioxide out of the atmosphere and store it in living plant tissue. Entergy Services| Inc. is an electric utility with a service territory that comprises portions of both the Lower Mississippi River Valley and the Gulf of Mexico coastline. This provides an opportunity to positively address both habitat losses noted above while at the same time addressing global warming| forest fragmentation| and biodiversity. Entergy| through its affiliation with the UtiliTree Carbon Company| is participating in projects that will investigate the feasibility of using bottomland hardwood reforestation on cleared marginal farmlands now managed by the Louisiana Department of Wildlife and Fisheries and the US Fish and Wildlife Service. Entergy has also begun a research project with the Environmental Protection Agency and the State of Louisiana. The research is a compost demonstration project that will utilize wood waste generated through our tree-trimming program as a compost material that will be mixed with low nutrient dredge material to create new coastal wetlands. Taken together| Entergy's initiatives will be able to address global warming through carbon sequestration| restore fragmented forest habitats| reduce coastal erosion and improve the quality of a vital coastal aquatic nursery habitat. Efforts will be made to manage the created habitats for biodiversity. Pulling all these ideas together creates an effect in which the whole is greater than the sum| of the parts. In such a synergy of ideas| there are no losers and the winners are both industry participants and the environment. (C) 1999 Elsevier Science B.V| All rights reserved. 5122,1999,3,4,Airless drying - Developments since IDS '94,Since its introduction to IDS'94 delegates| significant progress has been made with the development of airless drying technology. The ceramic industry internationally is beginning to benefit from both the energy use and drying time reductions it achieves| while on the basis of further theoretical work carried out since 1993 other industries| including the bioenergy sector| should also soon begin to exploit its advantages. As global warming becomes a reality and oil reserves decline| superheated steam drying and gasification of biomass will contribute to the mitigation of those problems. 5079,1999,2,4,An analysis of the influence of annual thermal variables on the occurrence of fifteen warmwater fishes,Multisource fish-sampling data and U.S. Geological Survey temperature data from streams throughout the United States were used to investigate the influence of derived thermal regime variables on the presence or absence of 15 common warmwater fish species. The 3-year average annual thermal regime was calculated for streams where presence or absence was known for these 15 species. Six variables estimated to be of biological importance to the winter and summer survival and recruitment of a species| including measures of feeding and nonfeeding periods| were calculated from these thermal regimes. Stepwise discriminant analysis and multiple regression were used to select optimal variables for creating multivariate models. Parametric and nonparametric multivariate discriminant analyses were then performed to test our ability to correctly classify presence or absence using the thermal variables. These statistical empirical models were able to correctly predict presence or absence with greater than 90% accuracy for 13 of 15 species. Nonparametric (Kth nearest neighbor) analyses had marginally more accurate predictions than parametric (linear) analyses. This technique may allow for an improved estimation of potential changes in distribution under various global warming scenarios. 5087,1999,2,2,An insect (Argyresthia retinella| Lep.| Yponomeutidae) outbreak in northern birch forests| released by climatic changes?,1. In the early 1990s| birch Betula pubescens L. forests in north-western Norway were damaged by the bud- and shoot-mining larvae of Argyresthia retinella not previously known for outbreaks. In 1993-96| the outbreak was mapped and changes in attack intensity and foliage structure were quantified by sampling birch twigs along transects from coast to inland. Results were considered in relation to a variable climate. 2. The outbreak extended 400 km along the coast| mainly within the lowest 100-150 m a.s.l. It started in the late 1980s and the attack intensity culminated in 1993-94. Repeatedly| 30-50% of the leaf-carrying shoots were damaged or killed. Trees compensated by sprouting clusters of shoots from undamaged shoots and| hence| increased foliage clumping. Eventually| twigs and branches died. 3| The overwintering post-diapause egg| the larva and the adult stages were considered the most sensitive to changes in temperature climate. The air temperature| averaged for a combination of these stages| was calculated for each year| as well as deviations from the long-term (1868-1996) average. 4| The 5-year running average of deviations approached or exceeded +1 degrees C three times: in the 1930s| around 1960 and around 1990. The third peak coincided with the outbreak of the 1990s. There are no reports of an A. retinella outbreak in either the 1930s or 1960s. However| in one photographic documentation from 1940| clumped foliage structure of birch suggests an outbreak in the 1930s. 5. Severe A. retinella attacks appear to be a fairly new phenomenon| possibly connected to recent high temperature deviations. If so| with the present air temperature climate| outbreaks may occur at intervals of approximate to 20-25 years. With a trend of decreasing air temperature| outbreaks may be less frequent. At higher temperatures| natural or from anthropogenic global warming| the outcome is more uncertain although more frequent outbreaks may occur initially. 6. It is recommended that foresters learn to identify damage made by A. retinella and include observations on this insect in their reporting. Monitoring A. retinella damage in the North and elsewhere| should contribute to the understanding of the outbreak ecology of this insect. 2270,1999,4,4,An interactive cirrus cloud radiative parameterization for global climate models,An interactive cirrus cloud radiative parameterization is developed for global climate models from recent observations and analytical results that more accurately characterize cirrus cloud optical and microphysical properties. The radiative properties are based on the assumption that cirrus clouds are composed of hexagonal crystals. For the infrared component| a new mass absorption coefficient is parameterized to calculate emissivity| and for the solar| single-scattering properties from an existing parameterization are modified and employed. The solar and infrared optical properties are given as a function of ice water content and effective particle size. Aircraft observations are used to parameterize the microphysical properties in terms of temperature| thus allowing the radiative properties to interact with the local model climate. The interactive cirrus radiative parameterization is evaluated in model-to-observation comparisons with a comprehensive set of cloud and radiation measurements obtained during the spring 1994 and fall 1995 Intensive Observation Periods of the Atmospheric Radiation Measurement program. It is shown that the model with the new parameterization calculates realistic infrared radiation and improved solar radiation incident at the surface. Specifically| biases in calculated solar direct and-diffuse fluxes are reduced by 60 and 40%| respectively. Further| the shortwave flux is shown to be more sensitive than the longwave flux to variability in the ice water content and in the base and top heights of observed clouds replicated in model calculations. The potential effect of the new parameterization on climate simulations is investigated in the context of initial radiative forcing. The new parameterization calculates a significantly different ice water path distribution from an existing parameterization that has been used for global climate change studies. For example| in the high latitudes of the summer hemisphere the new ice water path is larger by more than 7.7 g m(-2) (>100%)| and in the tropics it can be smaller by as much as -3.5 g m(-2) (similar to 80%). These differences lead to an increased solar albedo effect in the high gm latitudes of the summer hemisphere and a decreased greenhouse effect in the tropics| both of which contribute to a smaller| 2.26 W m(-2)| global- and annual-mean forcing of the surface-troposphere system. 4903,1999,4,2,An introduction to global warming,Thy physics of climate and of climate changes associated with increasing concentrations of greenhouse gases in the atmosphere are briefly presented. Construction of a "toy model" of the climate is discussed. Possibilities for reducing carbon dioxide emissions are indicated. Degrees of uncertainty characterizing predictions of climate responses to anthropogenic greenhouse gas emissions are presented. (C) 1999 American Association of Physics Teachers. 5110,1999,3,4,An overview of fast pyrolysis of biomass,Biomass fast pyrolysis is of rapidly growing interest in Europe as it is perceived to offer significant logistical and hence economic advantages over other thermal conversion processes. This is because the liquid product can be stored until required or readily transported to where it can be most effectively utilised. The objective of this paper is to review the design considerations faced by the developers of fast pyrolysis| upgrading and utilisation processes in order to successfully implement the technologies. Aspects of design of a fast pyrolysis system include feed drying; particle size; pretreatment; reactor configuration; heat supply; heat transfer; heating rates; reaction temperature; vapour residence time; secondary cracking; char separation; ash separation; liquids collection. Each of these aspects is reviewed and discussed. A case study shows the application of the technology to waste wood and how this approach gives very good control of contaminants. Finally the problem of spillage is addressed through respirometric tests on bio-oils concluding with a summary of the potential contribution that fast pyrolysis can make to global warming. (C) 1999 Elsevier Science Ltd. All rights reserved. 2275,1999,4,4,Analysis of atmospheric aerosols by PIXE: the importance of real time and complementary measurements,Particle-Induced X-ray Emission (PIXE) has been used for more than 30 yr in many urban and background air pollution studies. The technique has certainly contributed to the understanding of source-receptor relationship for aerosol particles as well as to aerosol physics and chemistry. In the last few years| where aerosol issues were strongly linked to global climate change through the relationship between aerosol and atmospheric radiation points to new challenges in atmospheric sciences| where PIXE could Flay an important role. Also the recognition for the inter-relationship between aerosol and liquid and gas phases in the atmosphere makes important to integrate PINE aerosol analysis with other complementary measurements. The use of Nephelometers and Aethalometers to measure scattering and absorption of radiation by aerosol particles can be done in parallel with particle filter collection for PIXE analysis. Parallel measurements of trace gases using traditional monitors as well as with new techniques such as Differential Optical Absorption Spectroscopy (DOAS) that can provide concentration of O-3| SO2| NO3| NO2| HCHO| HNO3| Benzene| Toluene| and Xylene| is also important for both urban and remote aerosol studies. They provide information that allows a much richer interpretation of PINE data. Recently developed instruments that provide real time aerosol data such as the Tapered Element Oscillating Microbalance (TEOM) PM10 monitor and automatic real time organic and elemental carbon analyzers provide extremely useful data to complement PINE aerosol analysis. The concentrations of trace elements measured by PIXE comprise only 10-30% of the aerosol mass| leaving the organic aerosol characterization and measurement with an important role. The aerosol source apportionment provided by PIXE analysis can be extended with other aerosol measurements such as scattering and absorption estimating for example| the radiative impact of each discriminated aerosol source. The aerosol bulk PIXE measurements can be complemented with soluble concentrations provided by Ion Chromatography (IC) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Recent developments in remote sensing techniques and products also enhance significantly regional aerosol studies. Three-dimensional air mass trajectories should be integrated in aerosol studies for urban and remote areas. The applications of these techniques to study urban aerosols from Sao Paulo and Santiago de Chile have broadened extensively the scientific scope of these studies. (C) 1999 Elsevier Science B.V. All rights reserved. 4917,1999,2,4,Analytic representation of the active layer thickness field| Kuparuk River Basin| Alaska,The initial response of permafrost to global warming could be an increase in active-layer thickness. Given that such changes could have severe consequences for human infrastructure and ecosystem stability| it is important to obtain information about spatial variations of the active layer corresponding to current climatic conditions| and to determine the magnitude of possible near-surface permafrost degradation associated with climatic change. Simple analytical solutions for frost and thaw penetration depth have long been available| but were used primarily for practical applications at point locations in cold-region engineering. One of these methods| developed at Moscow State University by Kudryavtsev and co-workers| was used to develop a spatially distributed analytic model that estimates the maximum annual depth of thaw. Kudryavtsev's procedures account for the effects of snow cover| vegetation| soil moisture| thermal properties| and regional climate| and provide estimates of surface temperature and active-layer thickness. GIS techniques were used to incorporate climate records| digital cartographic products| and field data into a spatially distributed estimate of active-layer thickness. Procedures were applied over a rectangular 22 300 km(2) area in north-central Alaska containing complex patterns of topography| vegetation| and soils. Validation procedures indicate that the Kudrayavtsev solution| adapted for spatial applications| yields accuracy and spatial resolution comparable to an existing semi-empirical method. The simplicity and low data requirements of the Kudryavtsev solution make it readily adaptable to different geographic scales and areas. The method has potential applications in climate-change studies. (C) 1999 Elsevier Science B.V. All rights reserved. 5038,1999,2,4,Analyzing investments for managing Lake Erie levels under climate change uncertainty,Analyses of investments that are irreversible and have uncertain benefits should consider the option of delaying a decision. For instance| the benefits of many water resource projects could change if global warming occurs. The magnitude of that warming is uncertain| and delaying projects until more information is available might be optimal. We examine whether this is true for construction of an outflow control structure for Lake Erie. Using Bayesian Monte Carlo (BMC)-based decision analysis| we find that considering climate uncertainty does make a difference. Climate change beliefs| in the form of prior distributions over transient climate scenarios| can affect the optimal strategy: in particular| climate change makes delaying construction more attractive. The option value of deferring the decision to build is as high as $20 million. Ignoring the possibility of climate warming can inflict an expected penalty as large as 20% of the cost of the control structure. We also compare climate risks to uncertainties in stage-damage curves and find that they are approximately of equal importance. 2295,1999,4,4,Application of a global discharge model to atmospheric model simulations in the BALTEX region,In this study| a hydrological discharge model is presented which may be applied as a tool to validate the simulation of the hydrologic cycle of atmospheric models that are used in climate change studies. It can also be applied in studies of global climate change to investigate how changes in climate may affect the discharge of large rivers. The model was developed for the application with the climate models used at the Max-Planck-Institute for Meteorology. It describes the translation and retention of the lateral waterflows on the global scale as a function of the spatially distributed land surface characteristics which are globally available. Here| global scale refers to the resolution of 0.5 degrees and lower| corresponding to a typical average gridbox area of about 2|500 km(2). The hydrological discharge model separates between the flow processes of overland flow| baseflow and riverflow. The model parameters are mainly functions of the gridbox characteristics of topography and gridbox length. The hydrological discharge model is applied to the BALTEX (Baltic Sea Experiment) region using input from an atmospheric general circulation model (ECHAM4) as well as from a regional climate model (REMO). The simulated inflows into the Baltic Sea and its sub-catchments are compared to observed and naturalized discharges. The results of this comparison are discussed and the simulated values of precipitation| surface air temperature and accumulated snowpack are compared to both observed data and surrogate data. 5073,1999,3,3,Application of helio-aero-gravity concept in producing energy and suppressing pollution,Fossil fuels account for about 80% of the world's annual energy demand. Renewables contribute 14% and nuclear some 6%. These roles will change as population grows| energy demand rises| cheap oil and gas are depleted| global warming effects continue rising and city pollution worsens the living conditions. The development of new and renewable energy resources and devices will emerge more aggressively to address the world energy and environment situation. The helio-aero-gravity power concept consists of an air turbine-generator system in a chimney installed at the center of a carefully selected piece of land where insolation is high. This land is covered by a transparent canopy with a small opening at the periphery. As the sun heats the land under the canopy| it heats the air to raise and force it into the chimney where it turns the rotor installed in the chimney| thus producing the electrical power with the generator. Under reasonable conditions with an efficiency of 5%| the power| thus calculated| would be 50 MW per square kilometer of land. An estimated cost of the energy delivered by a plant of 100 MW would be less than l%/kWh of electricity. Conversely| the air flow can be forced downward by spraying water at the top of the chimney in case suppression of pollution is desired in big cities. The cold air at the top sinks with the pollutant continuously| thus turning the rotor installed at the bottom of the chimney. The pros and cons of the concept will be discussed and details of the experimental plants and results| thus obtained| will be presented. (C) 1998 Elsevier Science Ltd. All rights reserved. 5093,1999,3,4,Application of life cycle assessment to manufacturing of nonferrous metals,Life cycle assessment (LCA) is a broad topic that is currently being discussed. However| little is known about the assessment method of environmental impacts expressing a single index| especially in Japan. Non ferrous metals are one of the basic materials for industrial products. The establishment of the assessment for these materials is important to improve the quality of LCA for products. We have proposed a method of assessment for total impact in Japan| and a case study of LCA is performed concerning the nonferrous metals in this paper. The stages considered in this LCA study are: goal and scope of the inventory analysis and impact assessment. The inventory data include the consumption of raw materials and the emissions through the mining| transport and manufacturing. Resource depletion| global warming| acidification| eutrophication and air pollution have been considered as impact categories. The main results of this study are summarized as follows| (1) The impacts of eutrophication| air pollution and resource depletion are serious for the production of aluminum. (2) The stages of the consumption of non oil and that of the production of non oil are serious for the production of zinc| because the large quantity of non oil such as cokes are consumed. (3) We have showed that the interpretation will differ if the criteria of materials for assessment are changed from weight (per kg) to tensile strength (per MN). 2247,1999,2,3,Arctic soil respiration: Effects of climate and vegetation depend on season,Arctic ecosystems are important in the context of global climate change because the most rapid rises in air temperature are expected at high northern latitudes during winter. The presence of extensive soil carbon reserves in the Arctic suggests that substantial feedbacks to CO(2)-induced climate change could occur if warming alters carbon cycling belowground. Characterization of the controls on regional patterns of belowground CO(2) release through the annual cycle is an important step towards evaluating potential feedbacks from arctic ecosystems to climate change. In this study| we assess seasonal control over the influences by climate and vegetation-type on CO(2) efflux from belowground in the Alaskan tundra. Our results indicate that climate had strong effects on belowground CO(2) release in both seasons. By contrast| vegetation-type had little impact on CO(2) efflux from belowground in winter but was the principal control in summer. Together| these results demonstrate that seasonality is a critical factor regulating climate and vegetation-type effects on belowground CO(2) release| which should be included in regional models of net carbon balance in arctic ecosystems. 5007,1999,2,4,Arctic soils: Spatial distribution| zonality and transformation due to global change,Published and unpublished information on Arctic soils| soil-forming factors and possible transformations of the soil cover due to global change are reviewed. In high latitudes the soil distribution is strongly controlled by geogenic factors (relief and substrates). Locally they transform the Arctic macroclimate| which is principally humid| to produce arid phenomena in the soil landscapes. All the soil processes from podzolization to salinization can be qualitatively distinguished in every region of the Arctic. Quantitatively| the effect of these soil-forming processes decreases with increasing latitude. A new zonal division of Arctic soils is proposed| comprising (1) High Arctic barren (tundra)| (2) Mid Arctic tundra and (3) Low Arctic and Subarctic tundra. In addition to climate warming| important consequences of global change are soil pollution and the physical disturbance of the Arctic soil cover. All the countries of the northern hemisphere are contributing to Arctic soil pollution. Winter warming associated with climate change could cause an intensification of cryoturbation in the continental part of Siberia and lead to the more active fossilization of soil carbon and the increased importance of the cryopedosphere as a carbon sink. Copyright (C) 1999 John Wiley & Sons| Ltd. 4918,1999,2,4,Are interdecadal sea level changes along the Indian coast influenced by variability of monsoon rainfall?,The Mumbai (Bombay) tide gauge data| the only century-long record in the Indian Ocean| show that interdecadal changes in sea level mimic those in rainfall over the Indian subcontinent. We propose that the link between rainfall and sea level arises from changes in salinity in coastal waters. Rivers fed by southwest monsoon (June-September) rainfall bring a large fraction of the runoff to the Bay of Bengal| from where it is transported to the west coast of India by an equatorward East India Coastal Current| which is triggered partly by the withdrawal of the southwest monsoon. The West India Coastal Current carries the low-salinity water from the bay as well as the runoff from local rivers northward. The advection of the riverine inflow to Mumbai occurs within a season. but the slow mixing in the ocean forces changes in the cross-shore density gradient on longer timescales. This density gradient forces a two-layer geostrophic circulation| with a surface current| which flows with the lighter water on its right| and an undercurrent. Lower (higher) salinity at the coast implies higher (lower) coastal sea level and a rise (fall) of the pycnocline at the coast. Thus the interdecadal variability of sea level along the Indian coast can be Linked directly to the variability of the monsoon| the major aspect of the climate of the region| but by a mechanism that is different from those generally proposed to link sea level to climate change; these hypotheses usually invoke a change in volume because of global warming. 4902,1999,3,2,Assessment of automotive fuels,Energy demand all over the world increases steadily and| within the next decades| is almost completely met by fossil fuels. This poses increasing pressure on oil supply and reserves. Concomitant is the concern about environmental pollution| especially by carbon dioxide from fossil fuel combustion| with the risk of global warming. Environmental well-being requires a modified mix of energy sources to emit less carbon dioxide| starting with a move to natural gas and ending with the market penetration of renewable energies| Efforts should focus on advanced oil and gas production and processing technologies and on regeneratively produced fuels like hydrogen or bio-fuels as well. Within the framework of an industrial initiative in Germany| a process of defining one or two alternative fuels was started| to bring them into the market within the next years. (C) 1999 Elsevier Science S.A. All rights reserved. 4952,1999,2,3,Assessment of the probability of extreme weather events and their potential effects in large conurbations,The likelihood of occurrence of extreme high-temperature run events is estimated for different values of the event intensity and persistence from very long synthetic time series of daily maximum temperatures generated by Monte Carlo simulations using a first-order autoregressive or Markov model. A theoretical analysis reveals a higher relative sensitivity of the simulated extreme event probabilities to changes in the variability of climate than to changes in its mean state. Moreover| this sensitivity relatively increases at a nonlinear rate the more extreme the event. The developed probabilistic model is applied in order to derive local scenarios of extreme high-temperature run events for a large conurbation like the city of Berlin assuming both arbitrary hypothetical and physically based new climate states described by changes in the model parameters (e.g. the mean| the standard deviation and the first-order autocorrelation of the daily maximum temperature time series). As a consequence of a 1.7 degrees C increase in the mean as well as a 19% increase in the temperature variability in July as predicted by the climate model ECHAM-1/LSG assuming an unrestricted future increase in the global atmospheric concentration of climate relevant greenhouse gases according to the IPCC Scenario A ("Business as usual") the intensity as well as the persistence of extreme high-temperature run events will rise considerably up to the end of the next century. In particular| intense hot spells characterized by at least five consecutive daily maximum temperatures equaling or exceeding 33 degrees C are expected to occur every eight years under the new climate conditions compared to a current repetition time of about 47 years. The potential environmental effects might be a significant increase in the heat-stress-related morbidity and mortality rate| an aggravation of the summer smog situation and a destabilization of the urban ecosystems. (C) 1999 Elsevier Science Ltd. All rights reserved. 5051,1999,4,4,Atmospheric lifetime and global warming potential of HFC-245fa,We describe the method used to compute the global warming potential of hydrofluorocarbon (HFC) 245fa (CHF2CH2CF3). The Atmospheric and Environmental Research (AER) two-dimensional (latitude-height) chemistry-transport model was used to calculate the atmospheric lifetime and atmospheric scale height of HFC-245fa. Assuming that reaction with OH is the only removal mechanism| the recommended rate constant from Jet Propulsion Laboratory [1997] (6.1 x 10(-13) exp (-1330/T) cm(3) s(-1)) implies a lifetime of 7.6 pears and an average atmospheric scale height of 35 km in the stratosphere. Using the IR absorption cross sections for HFC-245fa and CFC-11 determined in the laboratory| the AER one-dimensional radiative-convective model was used to calculate the radiative forcing| The value for HFC-245fa is 1.14 times larger than that for CFC-11 on a mass basis and 1.11 larger on a per molecule basis. The global warming potentials for HFC-245fa (relative to carbon dioxide) are 2400| 760| and 240 (based on the values for absolute global warming potential for carbon dioxide reported by Intergovernmental Panel on Climate Change [1996]) at integration time horizons of 20| 100| and 500 years| respectively. 4900,1999,4,4,Atmospheric lifetimes and global warming potentials of hydrofluoroethers: Reactivity toward OH| UV spectra| and IR absorption cross sections,The rate constants for the reactions of OH radicals with the fluorinated ethers| CHF2-O-CHF2 (HFOC-134) and CF3CH2-O-CH2CF3 (HFOC-356mff)| were measured using the flash photolysis resonance fluorescence technique over the temperature range 277-370 K to give the following Arrhenius expressions: k(HFOC-134)(T) = (0.63(-0.16)(+0.20)) x 10(-12) exp\{-(1646 +/- 76)/T\} cm(3) molecule(-1) s(-1)| k(HFOC-356mff)(T) (2.32(-0.41)(+0.46)) x 10(-12): exp\{-(790 +/- 47)/T\} cm(3) molecule(-1) s(-1). On the basis of the analysis of the available experimental results| the following Arrhenius expression can be recommended for the rate constant of the reaction between OH and HFOC-134: k(HFOC-134)(T) = (0.82(-0.24)(+0.34)) x 10(-12) exp\{-(1730 +/- 110)/T\} cm(3) molecule(-1) s(-1). Atmospheric lifetimes were estimated to be 24.8 years for HFOC-134 (23.8 years based on the results of this study alone) and 0.3 years for HFOC-356mff. Infrared absorption cross sections of HFOC-134| HFOC-356mff|and HFOC-125 (CHF2-O-CF3) were measured at T = 295 K from 500 to 1600 cm(-1) and the global warming potentials of the three compounds were estimated. Ultraviolet absorption spectra of the ethers were measured between 160 and 220 Mm. The general pattern of reactivity of hydrofluoroethers toward OH is discussed. 2286,1999,5,4,Atmospheric transmission of North Atlantic Heinrich events,We model the response of the climate system during Heinrich event 2 (H2) by employing an atmospheric general circulation model| using boundary conditions based on the concept of a "canonical" Heinrich event. The canonical event is initialized with a full-height Laurentide ice sheet (LIS) and CLIMAP sea surface temperatures (SSTs)| followed by lowering of the LIS| then warming of North Atlantic SSTs. Our modeled temperature and wind fields exhibit spatially variable responses over the Northern Hemisphere at each stage of the H2 event. In some regions the climatic responses are additive| whereas in other regions they cancel or are of opposite sign| suggesting that Heinrich event climatic variations may have left complex signatures in geologic records. We find variations in the tropical water balance and the mass balance of ice sheets| and implications for variations in terrestrial methane production from the contraction of northern permafrost regions and the expansion of tropical wetlands. 2290,1999,2,4,Atmospheric water vapor pressure over land surfaces: A generic algorithm with data input limited to air temperature| precipitation and geographic location,A lack of information for surface water vapor pressure (WVP) represents a major impediment to model-assisted ecosystem analysis for understanding plant-environment interactions or for projecting biospheric responses to global climate change. This paper reports on a generic algorithm that captures global variation in monthly WVP The algorithm solves WVP in terms of reduction from saturation WVP as a negative exponential function of potential evapotranspiration; the reduction rate per unit potential evapotranspiration in turn varies with monthly precipitation and a series of variables that distinguish local climate regimes. Data input to the algorithm is limited to monthly air temperature and precipitation| plus latitude| longitude and elevation. The algorithm is specified through regression fitting to monthly climate normal data from 852 stations around the world. It accounts for 96% of the variance in the WVP data| with a root mean square error of 0.17 kPa| or 12% of the data mean. The algorithm closely reproduces five-year sequential monthly WVP data for each of five selected United States locations representitative of diverse climate regimes: the average error generally falls within +/-12% of the data mean| and the absolute error within +/-0.2 kPa. Its projections also compare favorably against the WVP output from the General Circulation Models for temperature and precipitation conditions under the scenario of a doubled atmospheric carbon-dioxide concentration: the two fall within +/-10% of each other for 75% of a total 264 data cases| or within +/-20% for 94% of the cases. These statistics suggest that the spatially-based algorithm Is useful for projecting temporal variation in WVP| and for extrapolative applications beyond the fluctuation range of present climate. 2246,1999,2,3,Below-ground respiratory responses of sugar maple and red maple saplings to atmospheric CO(2) enrichment and elevated air temperature,The research described in this paper represents a part of a much broader research project with the general objective of describing the effects of elevated [CO(2)] and temperature on tree growth| physiological processes| and ecosystem-level processes. The specific objective of this research was to examine the below-ground respiratory responses of sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) seedlings to elevated atmospheric [CO(2)] and temperature. Red maple and sugar maple seedlings were planted in the ground in each of 12 open-top chambers and exposed from 1994 through 1997 to ambient air or air enriched with 30 Pa CO(2)| in combination with ambient or elevated (+4 degrees C) air temperatures. Carbon dioxide efflux was measured around the base of the seedlings and from root-exclusion zones at intervals during 1995 and 1996 and early 1997. The CO(2) efflux rates averaged 0.4 mu mol CO(2) m(-2) s(-1) in the root-exclusion zones and 0.75 mu mol CO2 m(-2) s-1 around the base of the seedlings. Mineral soil respiration in root-exclusion zones averaged 12% higher in the high temperature treatments than at ambient temperature| but was not affected by CO(2) treatments. The fraction of total efflux attributable to root + rhizosphere respiration ranged from 14 to 61% in measurements made around red maple plants| and from 35 to 62% around sugar maple plants. Root respiration rates ranged from 0 to 0.94 mu mol CO(2) s(-1) m(-2) of soil surface in red maple and from 0 to 1.02 in sugar maple. In both 1995 and 1996 root respiration rates of red maple were highest in high-CO(2) treatments and lowest in high temperature treatments. Specific red maple root respiration rates of excised roots from near the soil surface in 1996 were also highest under CO(2) enrichment and lowest in high temperature treatments. In sugar maple the highest rates of CO2 efflux were from around the base of plants exposed to both high temperature and high-CO(2)| even though specific respiration rates were lowest for this species under the high temperature and CO(2) enrichment regime. In both species| patterns of response to treatments were similar in root respiration and root mass| indicating that the root respiration responses were due in part to differences in root mass. The results underscore the need for separating the processes occurring in the roots from those in the forest floor and mineral soil in order to increase our understanding of the effects of global climate change on carbon sequestration and cycling in the below-ground systems of forests. 4961,1999,3,3,Benefits from managing farm produced nutrients,Manures and fertilizers are applied to agricultural lands in excess of recommended amounts| resulting in widespread pollution of surface and ground water and contributing a substantial source of greenhouse gases associated with global warming. By developing policies that exploit the value of farm produced nutrients| input costs can be minimized. Better accounting for or crediting of farm produced nutrients is leading to economically beneficial conservation of fertilizer. In addition| hog producers who own enough land may benefit from properly managing manure nutrients. Poultry litter is valuable as fertilizer and can be marketed by independent dealers to farmers in nutrient deficit areas| with very modest assistance from the government. Dairy producers may modify their past income support programs to finance central compost facilities. Although nutrient problems were neglected in the past| recent Federal initiatives and joint initiatives with states exploit many of these and other opportunities to avoid excessive application of nutrients to the land. 2263,1999,2,4,Biomass production and species composition change in a tallgrass prairie ecosystem after long-term exposure to elevated atmospheric CO2,To determine the long-term impact of elevated CO2 on primary production of native tallgrass prairie| we compared the responses of tallgrass prairie at ambient and twice-ambient atmospheric CO2 levels over an 8-year period. Plots in open-top chambers (4.5 m diameter) were exposed continuously (24 h) to ambient and elevated CO2 from early April to late October each year. Unchambered plots were monitored also. Aboveground peak biomass was determined by clipping each year in early August| and root growth was estimated by harvesting roots from root ingrowth bags. Plant community composition was censused each year in early June. In the last 2 years of the study| subplots were clipped on 1 June or 1 July| and regrowth was harvested on 1 October. Volumetric soil water content of the 0-100 cm soil layer was determined using neutron scattering| and was generally higher in elevated CO2 plots than ambient. Peak aboveground biomass was greater on elevated CO2 plots than ambient CO2 plots with or without chambers during years with significant plant water stress. Above-ground regrowth biomass was greater under elevated CO2 than under ambient CO2 in a year with late-season water stress| but did not differ in a wetter year. Root ingrowth biomass was also greater in elevated CO2 plots than ambient CO2 plots when water stress occurred during the growing season. The basal cover and relative amount of warm-season perennial grasses (C4) in the stand changed little during the 8-year period| but basal cover and relative amount of cool-season perennial grasses (C3) in the stand declined in the elevated CO2 plots and in ambient CO2 plots with chambers. Forbs (C3) and members of the Cyperaceae (C3) increased in basal cover and relative amount in the stand at elevated compared to ambient CO2. Greater biomass production under elevated CO2 in C4-dominated grasslands may lead to a greater carbon sequestration by those ecosystems and reduce peak atmospheric CO2 concentrations in the future. 5016,1999,3,3,Biomass-Balance Table for evaluating bioenergy resources,Bioenergy is expected to become one of the key energy resources to cope with global warming and exhaustion of fossil fuel resources. Biomass is renewable and free from net CO2 emissions as long as it is maintained sustainably. There are several studies concerning bioenergy potential| but they are hardly comparable because of the complexity of the assumed parameters| which relate to food| timber and paper supply| forest management| etc. In this study| bioenergy (expressed in Joules) is divided into plantation bioenergy produced on land and bioenergy recovered from biomass residues in the processes of harvest| conversion and consumption for food| timber and paper. We propose a "Biomass Balance Table"| which shows systematically the flows of various biomass forms. The scheme of a Biomass-Balance Table is similar to that of an energy-balance table. The steps of the biomass processing (i.e. harvesting| conversion and consumption) are expressed in the column| and biomass forms are expressed in the row. Tables have been constructed for 10 regions in the world in 1990. The world has an existing energy potential from biomass residues of 88 EJ (i.e. 26% of 335 EJ of primary energy supply in 1990) and Japan has 2.02 EJ (10% of 19.52 EJ of primary energy supply in 1990). North America| the former USSR and eastern Europe| and Western Europe have large potentials of wood biomass residues and other Asian countries and the centrally-planned economies of Asia have large potentials food biomass residues. (C) 1999 Elsevier Science Ltd. All rights reserved. 4953,1999,3,3,Can solar cooking save the forests?,Cooking with the sun has become a potentially viable substitute for fuelwood in food preparation in much of the developing world. Fuelwood scarcity is a growing problem that has thus far been poorly addressed. Solar cooking is one possible solution but its acceptance has been limited partially due to cultural barriers| relatively high start-up costs| and a lack of continued support subsequent to introduction. One possible source of some funding for solar cookers may be the Clean Development Mechanism (Article 12 of the Kyoto Protocols) aimed at reducing carbon emissions to curtail the impact of global warming. Using Haiti as an example| CDM funding is shown to be promising but only a partial solution. With CDM as a possible source of at least seed capital| more ambitious solar cooking programs are feasible but their success will be a function of addressing cultural barriers and providing support for adaptation well beyond the introductory stage. (C) 1999 Elsevier Science B.V. All rights reserved. 5018,1999,2,4,Carbon dioxide exchange in a high-arctic fen estimated by eddy covariance measurements and modelling,The high-arctic environment is an environment where the consequences of global warming may be significant. In this paper we report on findings on carbon dioxide and water vapour fluxes above a sedge-dominated fen at Zackenberg (74 degrees 28'N| 20 degrees 34' W) in The National Park of North and East Greenland. Eddy covariance measurements were initiated at the start of the growing season and terminated shortly before its end lasting 45 days. The net CO2 nux during daytime reaches a high of 10 mu mol m(-2)s(-1)| and around the summer solstice| net CO2 assimilation occurred at midnight| resulting in net carbon gain during the night. The measured carbon dioxide fluxes compare well to estimates based on the photosynthesis model by Collatz et al. (1991). The total growing-season net ecosystem CO2 exchange was estimated to be 96 g cm(-2) based on the carbon dioxide model and micrometeorological data. Finally| the combined CO2 assimilation and soil respiration models are used for examining the dependence of the carbon dioxide budget on temperature. The ecosystem is found to function optimally given the present temperature conditions whereas either an increase or a decrease in temperature would reduce the ecosystem CO2 accumulation. An increase in temperature by 5 degrees C would turn the ecosystem into a carbon dioxide source. 5109,1999,4,4,Carbon induced subsoil denitrification of (15)N-labelled nitrate in 1 m deep soil columns,Nitrate in soils is potentially a contaminant of groundwater and can also be denitrified to form nitrous oxide (N(2)O)| a global warming gas that is also involved with stratospheric ozone depletion. The objective of this work was to examine the fate of (15)N-labelled NO(3)(-) when it was injected into the subsoil (80 cm) in the presence of carbon. Gas fluxes from the soil surface and gas concentrations in the soil profile were monitored for 38 d. On average| after this time only 13% of the (15)N-labelled N was present as NO(3)(-) with immobilisation (54%)| entrapment in soil pore space (7%)| dissolution of N in soil water (2%)| gas fluxes from the soil column surface (N(2)O < 1%| N(2) 1.8%) and unaccounted for (15)N (20%) making up the remainder of the (15)N balance. As (15)N-labelled N gases diffused from the zone of denitrification towards the soil surface the ratio of N(2)O-N:(N(2)O-N + Na) decreased (range of 0.90 to 0.17). (C) 1998 Elsevier Science Ltd. All rights reserved. 5106,1999,3,3,Carbon sequestration and conservation of tropical forests under uncertainty,Concern for global warming has focused attention on the rob of tropical forests in the reduction of ambient CO(2) levels and mitigation of climate change. Deforestation is a major land use change in the tropics| with forest resources undergoing degradation through the influence of logging and conversion to other uses. Land use change is a product of varied local and regional resource use policies. Management of forest resources is one such major temporal factor| influencing resource stability and the carbon pool. Under a given management policy| both the long period of forest growth| and the slow turnover and decay of the carbon pool| enhance the relevance of stand level management policies as cost-effective mechanisms mitigating climate change. Apart from regional level uncertainties like the nature of land use and the estimation of carbon storage in vegetation and soil| the carbon flux of tropical forests is greatly influenced by uncertainty in regenerative capacity of forests and in harvest and management policies. A case study from India is used to develop a transition matrix model of natural forest management| and to explore the economic implications of maintaining and expanding existing carbon sinks. The study further explores the significance of investments in additional carbon sink in plantation forests| given continued uncertainty in natural forest management. 4959,1999,3,4,Carbon storage after long-term grass establishment on degraded soils,Recent concern about global warming has led to attempts to estimate the effects of management on carbon sequestration in soil. The objective of this study is to determine the amount of soil organic carbon (SOC) degraded by agricultural practices and the rate of carbon sequestration in soils after restoration of grass for various periods of time. The SOC contents of previously cultivated clay soils (Udic Haplusterts) in central Texas returned to grass 6| 26| and 60 years ago are compared with those of soils in continuous agriculture for more than 100 years and those of prairie soils that have never been tilled. Surface (0 to 5 cm) SOC concentration ranged from 4.44 to 5.95% In the prairie to 1.53 to 1.88% in the agricultural sites. Carbon concentration in restored grasslands was generally intermediate to that reported for the native prairie and agricultural sites. The SOC mass in the surface 120 cm of the agricultural soils was 25 to 43% less than that of native prairie sites. After the establishment of grasses| SOC mass in the grass sites was greater than at the agricultural sites. A linear relationship between the length of time in grass and the amount of SOC sequestered in the surface 60 cm Gt well for time periods from 6 to 60 years. The slope of this function provided an estimate of the carbon sequestration rate| in this case 447 kg C ha(-1) yr(-1)| At this rate| it would require nearly an additional century (98 years) for the 60-year grass site to reach a carbon pool equivalent to that of the prairie. 4914,1999,3,1,CFC and Halon replacements in the environment,Substitute fluorocarbons may have direct environmental impact| for trample as greenhouse gases| or indirect impacts through the products of their decomposition in the environment. The mechanisms of that atmospheric decomposition are reviewed here and shown to be well established now. The end products are halogen acids and trifluoroacetic acid| all of which pre-exist in the environment in quantities greater than are expected to arise from fluorocarbon use and emissions. Furthermore| the growth in use of fluorocarbon replacements has been shown to be far less than the fall in CFC and Halon production. Hydrochlorofluorocarbons (HCFCs) have replaced less than one third of CFCs and are| themselves| ozone depleting substances that will be phased out under the Montreal Protocol. The growth in hydrofluorocarbons (HFCs) amounts to about 10% of the fall in CFCs. It is likely that the impact of new fluorocarbons on climate change will be a very small fraction of the total impact| which comes mainly from the accumulation of carbon dioxide in the atmosphere. (C) 1999 Elsevier Science S.A. All rights reserved. 4946,1999,2,3,Changes in heat index associated with CO2-induced global warming,Changes in Heat Index (a combined measure of temperature and humidity) associated with global warming are evaluated based on the output from four extended integrations of the GFDL coupled ocean-atmosphere climate model. The four integrations are: a control with constant levels of atmospheric carbon dioxide (CO2)| a second integration in which an estimate of the combined radiative forcing of greenhouse gases and sulfate aerosols over the period 1765-2065 is used to force the model| and a third (fourth) integration in which atmospheric CO2 increases at the rate of 1% per year to double (quadruple) its initial value| and is held constant thereafter. While the spatial patterns of the changes in Heat Index are largely determined by the changes in surface air temperature| increases in atmospheric moisture can substantially amplify the changes in Heat Index over regions which are warm and humid in the Control integration. The regions most prone to this effect include humid regions of the Tropics and summer hemisphere extra-tropics| including the southeastern United States| India| southeast Asia and northern Australia. 4913,1999,3,4,Chlorofluorocarbon to hydrofluoroalkane formulations: An industry perspective,The medications prescribed to treat asthma are provided in a range of delivery systems| designed to give patients a choice in how they take their inhaled medication. These include the mainstay of asthma therapy| the metered dose inhaler (MDI)| and the breath-operated inhalers. One of the major challenges that all the leading companies in the respiratory area have faced in recent years is the environmental effects of chlorofluorocarbons. The pharmaceutical industry recognized the need to reformulate MDI products containing chlorofluorocarbons| and a number of companies began to develop alternatives in the late 1980s| To help facilitate this change in products| an industry consortium was formed (International Pharmaceutical Aerosol Consortium)| and this has managed many of the overarching issues. After an extensive search was conducted the most suitable alternatives were the hydrofluoroalkanes| which do not contain chlorine| are ozone friendly| and have lower global-warming potentials than the chlorofluorocarbons that they are replacing| To date it is estimated that the industry has invested over $1.0 billion ($US) on global research and development efforts. The first countries to launch the nonchlorofluorocarbon MDIs hare been in Europe| and now salbutamol and 2 inhaled steroids are widely available across Europe in their nonchlorofluorocarbon form Clinical testing has been extensive| and patient acceptance of the new products has proved to be high| Maintaining the smooth progress of the global transition is important| and continued dialogue between all key stakeholders should ensure success in this area. 2237,1999,4,4,Clathrate eustasy: Methane hydrate melting as a mechanism for geologically rapid sea-level fall,Although submarine methane hydrates or clathrates have been highlighted as potential amplifiers of modern global climate change and associated glacio-eustatic sea-level rise| their potential role in sea-level fall has not been appreciated. Recent estimates of the total volume occupied by gas hydrates in marine sediments vary 20-fold| from 1.2 x 10(14) to 2.4 x 10(15) m(3). Using a specific volume change on melting of -21%| dissociation of the current global inventory of hydrate would result in a decrease of submarine hydrate volume of 2.4 x 10(13) to 5.0 x 10(14) m(3). Release of free gas bubbles present beneath hydrates would increase these volumes by 1.1-2.0 x 10(13) m(3). The combined effects of hydrate melting and subhydrate gas release would result conservatively in a global sea-level fall of 10-146 cm. Such a mechanism may offset some future sealevel rise associated with thermal expansion of the oceans. It could also explain anomalous sealevel drops during ice-free periods such as the early Eocene| the Cretaceous| and the Devonian. 5115,1999,3,2,Clean technology using cogeneration concepts for simultaneous production of electricity| steam| and industrial gases: A route to zero pollution discharge - A case study for enhanced oil recovery in Canada,Energy is the most critical factor for the growth of a nation's economy. However| its use has a major impact on the environment especially by discharging air pollutants into the atmosphere. In addition| energy production from fossil fuel| the world's most important fuel| is recently known to be the key contributor of CO2 (a major greenhouse gas) resulting in global warming problems. This article is an extension of our earlier research work to demonstrate how cogeneration concepts can be used to reduce production costs and simultaneously produce electricity| steam as well as industrial gases such as CO2. With cogeneration| there is very little air pollution discharged into the atmosphere. We discuss a case study of an enhanced oil recovery (EOR) application. 2261,1999,2,2,Climate and habitat availability determine 20th century changes in a butterfly's range margin,Evidence of anthropogenic global climate change is accumulating| but its potential consequences for insect distributions have received little attention. We use a 'climate response surface' model to investigate distribution changes at the northern margin of the speckled wood butterfly Para| ge aegeria. We relate its current European distribution to a combination of three bioclimatic variables. We document that P. aegeria has expanded its northern margin substantially since 1940| that changes in this species) distribution over the past 100 years are likely to have been due to climate change| and that I? aegeria will have the potential to shift its range margin substantially northwards under predicted future climate change. At current rates of expansion| this species could potentially colonize all newly available climatically suitable habitat in the UK over the nest 50 years or more. However| fragmentation of habitats can affect colonization| and Mle show that availability of habitat may be constraining range expansion of this species at its northern margin in the UK. These lag effects may be even more pronounced in less-mobile species inhabiting more fragmented landscapes| and highlight how habitat distribution will be crucial in predicting species' responses to future climate change. 5137,1999,2,4,Climate change and future hydroclimate for the Upper Crooked River| Oregon,Upper Crooked River drains a semiarid elevated lava plain supporting a mixed vegetation cover of juniper| sagebrush| and grass. The majority of basin farm income is derived from livestock grazing on non-irrigated public and private land. Average annual water balance surplus is a modest 75 mm. A watershed model run for 108 consecutive months defines present-clay hydroclimate as a basis for assessing changes related to global warming. Future watershed surplus is modeled assuming current land-use and grazing practices using monthly temperature and precipitation changes derived from a limited area model nested in a global circulation model. In the simulated warmer and wetter climate| peak surplus occurs three months earlier in January as an increased proportion of precipitation occurs as rain rather than snow Severe decreases in water availability to plants accompany elevated evapotranspiration in all months. The sensitivity of the watershed to evapotranspiration is attributable to the cool season concentration of rainfall and evapotranspiration increases that magnify moisture deficits and drought in the summer. Compared to present-day climate| modeled future hydroclimate indicates severely limited watershed moisture supplies requiring flexible resource management plans. 4985,1999,2,4,Climate change and sustainable water resources: placing the threat of global warming in perspective,Predicted climate change over the coming decades is likely to add measurable stress to water resources in many regions of the world| including some areas that are currently well endowed. The stresses are likely to involve changes in the frequency of extreme events as well as gradual changes in mean annual net resources. The paper analyses these predictions. It also attempts to place them in context| first| comparing their impact with other major barriers to sustainability| such as increasing demand| wastage| poor water resources assessment and international conflict| and| secondly| considering the limitations of current predictive techniques. 4895,1999,2,4,Climate change has affected the breeding date of tree swallows throughout North America,Increasing evidence suggests that climate change has affected the breeding and distribution of wildlife. If such changes are due to global warming| then we should expect to see large-scale effects. To explore for such effects on avian reproduction| we examined 3450 nest records of tree swallows from across North America. The egg-laying date in tree swallows advanced by up to nine days during 1959-1991. This advance in phenology was associated with increasing surface air temperatures at the time of breeding. Our analysis controlled for several potentially confounding variables such as latitude| longitude| breeding density and elevation. We conclude that tree swallows across North America are breeding earlier and that the most likely cause is a long-term increase in spring temperature. 4983,1999,2,4,Climate change impacts and responses in the Philippines: water resources,The Philippines| like many of the world's poor countries| will be among the most vulnerable to the impacts of climate change because of its limited resources. As shown by previous studies| occurrences of extreme climatic events like droughts and floods have serious negative implications for major water reservoirs in the country. A preliminary and limited assessment of the country's water resources was undertaken through the application of general circulation model (GCM) results and climate change scenarios that incorporate incremental changes in temperature and rainfall and the use of a hydrological model to simulate the future runoff-rainfall relationship. Results showed that changes in rainfall and temperature in the future will be critical to future inflow in the Angat reservoir and Lake Lanao| with rainfall variability having a greater impact than temperature variability. In the Angat reservoir| runoff is likely to decrease in the future and be insufficient to meet future demands for water. Lake Lanao is also expected to have a decrease in runoff in the future. With the expected vulnerability of the country's water resources to global warming| possible measures to cope with future problems facing the country's water resources are identified. 5005,1999,3,4,Climate change policy: quantifying uncertainties for damages and optimal carbon taxes,Controversy surrounds climate change policy analyses because of uncertainties in climatic effects| impacts| mitigation costs and their distributions. Here we address uncertainties in impacts| and provide a method for quantitative estimation of the policy implications of such uncertainties. To calculate an "optimal" control rate or carbon tax a climate-economy model can be used on estimates of climate damages resulting from warming scenarios and several other key assumptions. The dynamic integrated climate-economy (DICE) model| in its original specification? suggested that an efficient policy for slowing global warming would incorporate only a relatively modest amount of abatement of greenhouse gas emissions| via the mechanism of a small (about $5 per ton initially) carbon tax. Here| the DICE model is reformulated to reflect several alternate published estimates and opinions of the possible damages from climatic change. Our analyses show that incorporating most of these alternate damage estimates into DICE results in a significantly more aggressive optimal policy than that suggested by the original model using a single damage function. In addition| statistical distributions of these damage estimates are constructed and used in a probabilistic analysis of optimal carbon tax rates| resulting in mostly much larger (but occasionally smaller) carbon taxes than those of DICE using point values of damage estimates. In view of the large uncertainties in estimates of climate damages| a probabilistic formulation that links many of the structural and data uncertainties and thus acknowledges the wide range of "optimal" policies is essential to policy analysis| since point values or "best guesses" deny policy makers the opportunity to consider low probability| but policy-relevant| outliers. Our presentation is offered as a prototypical example of a method to represent such uncertainties explicitly in an integrated assessment. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. 2289,1999,4,2,Climate change scenarios for global impacts studies,We describe a set of global climate change scenarios that have been used in a series of studies investigating the global impacts of climate change on several environmental systems and resources - ecosystems| food security| water resources| malaria and coastal flooding. These scenarios derive from modelling experiments completed by the Hadley Centre over the last four years using successive versions of their coupled ocean-atmosphere global climate model. The scenarios benefit from ensemble simulations (made using HadCM2) and from an un-flux-corrected experiment (made using HadCM3)| but consider only the effects of increasing greenhouse gas concentrations. The effects of associated changes in sulphate aerosol concentrations are not considered. The scenarios are presented for three future time periods - 30-year means centred on the 2020s| the 2050s and the 2080s - and are expressed with respect to the mean 1961-1990 climate. A global land observed climatology at 0.5 degrees latitude/longitude resolution is used to describe current climate. Other scenario variables - atmospheric CO(2) concentrations| global-mean sea-level rise and non-climatic assumptions relating to population and economy - are also provided. We discuss the limitations of the created scenarios and in particular draw attention to sources of uncertainty that we have not fully sampled. (C) 1999 Elsevier Science Ltd. All rights reserved. 2249,1999,2,3,Climate change scenarios for impact assessment in Cuba,Determining seasonal and regional patterns of climate change is in growing demand for the assessment of the potential impacts on climate-related economic activities| such as agriculture or water resource management. This paper presents the results of the work done to determine possible patterns of CO2-induced climate change in Cuba based on the IPCC's best estimate of climate sensitivity and using IS92a and KYOTOA1 emission scenarios. The climate change scenarios were prepared combining general circulation model (GCM) results and output from the MAGICC climate model. The results of this study show that the methodology and the GCMs selected provide a large range of regional climate change and guarantee that the climatic change scenarios developed can be applied to explore a wide spectrum of the potential climate changes in different environments and social sectors in Cuba. 5095,1999,4,2,Climate evolution: from the recent past to the future,The aim of this article is twofold. We first summarize our current scientific knowledge about the potential influence of human activities on climate. This review is largely based on the conclusions of the 1995 IPCC report (International Panel on Climate Change). An increase in atmospheric concentrations of greenhouse gases has been observed since 1750 (CH4 = 145 %; CO2 = 30 %; N2O = 15 %) and in the temperature of the Earth's surface since 1860 (between 0.3 and 0.6 degrees C). This report suggests a discernable human influence on climate and predicts significant global warming for the next century (1 to 3.5 degrees C) as a result of the anthropogenic increase of the greenhouse effect. We then show how studies of past climates have| over the last ten years| contributed to this problem by providing information relevant to the future of our climate. Important results concern the existence of a relationship between climate and concentrations of greenhouse gases for more than 200 000 years| the discovery of rapid climatic changes (similar to 10 degrees C in a few decades in Greenland) and the reconstruction of recent climate showing that the 20th century is the warmest since 1 400 AD. ((C) Academie des sciences / Elsevier| Paris). 5129,1999,4,4,Climate modelling: Achievements and prospects,The significant progress made with coupled (atmosphere-ocean) general-circulation models (CGCMs) over the past decade or so is discussed in the context of the reports of the Intergovernmental Panel on Climate Change (IPCC). In their first report in 1990| most climate-change GCMs were atmospheric GCMs coupled to 'slab' ocean models and being used only to determine the 'equilibrium' climate response to specified increases in carbon dioxide. The wide range of estimates of their 'climate sensitivity' is discussed| especially in the context of the uncertainty introduced by model sensitivity to representations of cloud. The modelling focus then moved to transient-response| climate-change experiments. These and the related modelling problems are noted; as are the simultaneous growing awareness and improved quantification of a range of natural and human-induced radiative forcings. The consequent inclusion of this information in CGCMs to study the detection and attribution of climate change| leading to the IPCC statement in their 1995 report that 'the balance of evidence suggests that there is a discernible human influence on global climate'| is also discussed. A significant modelling breakthrough since the 1995 report is the capability of a few CGCMs to produce stable and realistic climate (control) simulations without using artificial 'flux adjustments'. This is illustrated with results from such a model| the Hadley Centre HadCM3. In conclusion| a brief perspective is given of high-priority modelling developments and applications to be addressed over the next decade. 5039,1999,2,4,Climatic changes and infectious diseases: Malaria and tick-borne relapsing borreliosis.,Malaria and tick-borne borreliosis are two vector-borne diseases whose epidemiology in Africa has been affected by climatic changes observed since the early 1970's. In the case of Borrelia crocidurae relapsing fever; the persistence ofsub-Saharan drought has been associated with a spread of the tick vector Alectorobius sonrai which was previously restricted to the Sahara and the Sahel. Now the disease has a high incidence in the Sudan savanna of West Africa where if was previously absent. In the case of malaria| drought has significantly reduced the distribution| abundance| or infection rate of anopheline vectors in these areas. However; the decrease of malaria transmission has had no significant impact on morbidity and mortality because of the specific modalities of naturally acquired immunity to malaria. In parts of the world where malaria is unstable or has been eradicated| global worming cannot by itself increase or reintroduce malaria| since other factors play a much more important role in the epidemiology and control of malaria. However the marked climatic anomalies which are observed some years may locally contribute to the occurrence of epidemics| as has been observed in limited areas of Southern and Central America| Southern Asia and Eastern Africa in relation to El Nino Southern Oscillation. (C) 1999 Elsevier; Paris. 2230,1999,5,4,Climatically related millennial-scale fluctuations in strength of California margin oxygen-minimum zone during the past 60 k.y.,A strong oxygen-minimum zone (OMZ) currently exists along the California margin because of a combination of high surface-water productivity and poor intermediate-water ventilation. However| the strength of this OMZ may have been sensitive to late Quaternary ocean-circulation and productivity changes along the margin| Although sediment-lamination strength has been used to trace ocean-oxygenation changes in the past| oxygen levels on the open margin are not sufficiently low for laminations to form. In these regions| benthic foraminifera are highly sensitive monitors of OMZ strength| and their fossil assemblages can be used to reconstruct past fluctuations. Benthic foraminiferal assemblages from Ocean Drilling Program Site 1017| off Point Conception| exhibit major and rapid faunal oscillations in response to late Quaternary millennial-scale climate change (Dansgaard-Oeschger cycles) on the open central California margin. These faunal oscillations can be correlated to and are apparently synchronous with those reported from Santa Barbara Basin. Together they represent major fluctuations in the strength of the OMZ which were intimately associated with global climate change-weakening| perhaps disappearing| during cool periods and strengthening during warm periods. These rapid| major OMZ strength fluctuations were apparently widespread on the Northeast Pacific margin and must have influenced the evolution of margin biota and altered biogeochemical cycles with potential feedbacks to global climate change. 4989,1999,2,4,CO(2) flux in Arctic and alpine dry tundra: Comparative field responses under ambient and experimentally warmed conditions,We compared growing season CO(2) flux patterns between botanically similar arctic and alpine dry tundra ecosystems in Alaska and Colorado under ambient and experimentally warmed conditions. Measurements were taken during the 1997 growing season| 3 yr after the warming treatments were begun. Under ambient weather conditions| arctic dry tundra at Toolik Lake| Alaska was a net source (4 g CO(2)-C m(-2)) of CO(2) to the atmosphere| while alpine dry tundra at Niwot Ridge| Colorado| was a net CO(2) sink (7 g CO(2)-C m(-2)) during the growing season. Experimental warming of arctic tundra by 1 to 3 degrees C| resulted in a sevenfold (32 g CO(2)-C m(-2)) increase in this ecosystem's carbon source activity. Similar warming in alpine tundra changed this ecosystem from a net carbon sink to a net carbon source of 8 g CO(2)-C m(-2) over the growing season. In the Arctic| increased CO(2) efflux with warming was largely the result of increased rates of ecosystem respiration throughout the entire growing season| while in the alpine ecosystem respiration increased only early in the growing season. Rates of photosynthesis were generally not affected by experimental warming at either site. These data suggest that global warming will accentuate the carbon source activity of dry tundra in the northern foothills of Alaska and will change the net CO(2) exchange of alpine dry tundra in the northern Rocky Mountains from a net CO(2) sink to a source. 4960,1999,3,4,CO2 emissions and the steel industry's available responses to the greenhouse effect,The Steel Industry has decreased its emissions of greenhouse gases by a factor of 3 in the last 30 years| However| the prospect of Global Warming| even if it is still a matter of controversy| makes it necessary to explore the issue further| Increasing steel recycling| i|e| the use of scrap| would be the most realistic near-term answer of the Steel Industry to a further decrease in CO2 emissions. In the long term| some interesting R&D paths are left open.
5074,1999,2,4,CO2 emissions from soil in response to climatic warming are overestimated - The decomposition of old soil organic matter is tolerant of temperature,The storage of organic carbon in soil is predicted to decrease with global warming because the decomposition of organic matter is expected to accelerate relative to the net primary production (NPP) of vegetation. This decrease would substantially increase the atmospheric CO2 concentration because soil contains twice as much C as the present atmosphere and the decomposed C from soil will be released to the atmosphere. These predictions of the decrease in soil C storage are| however| largely dependent on the implied assumption that the decomposition of all soil organic matter is as sensitive to temperature as is the decomposition of young litter. We used measurements of the amount and age of soil C and the decomposition of litter on temperature gradients and a simple model describing soil C dynamics to show that the decomposition of old soil organic matter is resistant to changes in temperature. Accordingly| in response to climatic warming| we estimate decomposition to accelerate significantly less than previously expected| and predict that the C storage of boreal forest soils will increase. 2294,1999,2,3,Coastline regression of the Romagna region| Italy| due to natural and anthropogenic land subsidence and sea level rise,The Romagna coastal area in the Northern Adriatic Sea has experienced in recent times continuous changes because of its precarious environment and low ground elevation above mean sea level (msl). Major processes that may influence the stability of the coast profile include land subsidence of both natural and anthropogenic origin and the msl rise caused by global climate change. According to the most accredited modeling predictions msl is expected to rise by almost 0.5 m over the next century because of the greenhouse effect. Natural land subsidence is the result of deep downward tectonic movement and consolidation of geologically recent deposits. It may be estimated in the range of 2-2.5 mm/yr in the Ravenna area and twice as much in the Po River delta. Anthropogenic land subsidence is primarily related to groundwater pumping from the upper fresh water aquifer system and gas production from Plio-Pleistocene reservoirs. Geodetic surveys from 1953 to 1990 provide documentary evidence of cumulative land settlement exceeding 0.8 m and 1.2 m at Marina di Ravenna and Cesenatico| respectively. In this study we estimate both natural and anthropogenic land subsidence for the years 2015| 2050| and 2100 with the aid of ad hoc finite element simulation models. The use of these predictions together with the expected msl rise shows that many present lowlands may be permanently submerged at the end of the next century. The extent of the flooded area of the Romagna coastal region can be as much as 690 and 910 km(2)| using optimistic and pessimistic land subsidence scenarios| respectively. A local detailed analysis indicates that the areas around the cities of Ravenna and Cesenatico may be seriously affected by sea water ingression while the city of Rimini is well protected because of its relatively high elevation above msl. 4970,1999,3,4,Comparison of rapeseed and mineral oils using Life-Cycle Assessment and Cost-Benefit Analysis,A combination of life-Cycle Assessment (LCA) and Cost-Benefit Analysis (CBA) was used to evaluate and compare the relative environmental impacts and socio-economic costs of several products| made from either rapeseed oil or mineral oil in the UK. The chainsaw bar oil case study is used to demonstrate the methodologies used and results obtained. Chainsaw bar oil is a total-loss oil| and has considerable potential for substitution of the conventional base oil (mineral oil) with rapeseed oil. Results are presented from LCA impact assessments of the mineral oil and rapeseed oil chainsaw lubricants Several scenarios were compared using different co-product allocation and alternative land-use assumptions. Global warming potential (GWP) impacts were lower for rapeseed chainsaw oil| in ail scenarios| than for the mineral oil product. Other environmental impacts illustrated that both assumptions (i.e. whether to examine the total or marginal impacts) and allocation can strongly influence conclusions. The most realistic scenario for rapeseed oil was considered to be 70% allocation of burdens to the oil| with winter wheat impacts subtracted from those of oilseed rape. With this scenario| ail environmental impacts considered for chainsaw lubricants were lower for rapeseed oil. Monetary valuation of impacts through CBA varied| depending on the valuation system used| but in general rapeseed oil chainsaw lubricant had lower costs than the mineral oil product. Allocating some of the environmental burdens of crop production and crushing to rapeseed meal| and consideration of marginal impacts relative to alternative land uses increased the apparent environmental benefits of rapeseed oil chainsaw lubricant. Combination of ICA and CBA will require further development but affords new opportunities for socio-economic interpretation of environmental aspects. 5078,1999,2,4,Consumption of atmospheric methane by soils: A process-based model,A process-based model for the consumption of atmospheric methane (CH(4)) by soils was developed to identify the most important factors affecting uptake rates and to determine whether the current uncertainties in the estimated size of the global soil sink might be reduced. Descriptions of diffusion and microbial oxidation processes| which together determine the CH(4) flux| were included. The results suggest that the global sink strength lies within the range 20-51 Tg yr(-1) CH(4)| with a preferred value of 38 Tg yr(-1) CH(4). Dry tropical ecosystems account for almost a third of this total. Here microbial activity rather than diffusion is limiting uptake. It is also in these areas that the impact of any intensification in agriculture will be the most pronounced| with a possible future reduction in uptake in excess of 3 Tg y(-1) CH(4). This is in contrast to the overall impact of global warming| which is expected to leave the size of the global soil sink relatively unchanged. 2221,1999,4,4,Continuous long-term measurements of soil-plant-atmosphere variables at a forest site,It is a major challenge in modem science to decrease the uncertainty in predictions of global climate change. One of the largest uncertainties in present-day global climate models resides with the understanding of processes in the soil-vegetation-atmosphere-transfer (SVAT) system. Continuous| long-term data are needed in order to correctly quantify balances of water| energy and CO2 in this system and to correctly model it. It is the objective of this paper to demonstrate how a combined system of existing sensor| computer| and network technologies could be set up to provide continuous and reliable long-term SVAT-process data from a forested site under almost all environmental conditions. The Central Tower Site (CTS) system was set up in 1993-1994 in a 25 m high boreal forest growing on a highly heterogeneous till soil with a high content of stones and blocks. It has successfully monitored relevant states and fluxes in the system| such as atmospheric fluxes of momentum| heat| water vapour and CO2| atmospheric profiles of temperature| water vapour| CO2| short-and long-wave radiation| heat storage in soil and trees| sap-flow and a variety of ecophysiological properties| soil-water contents and tensions| and groundwater levels| rainfall and throughfall. System uptime has been more than 90% for most of its components during the first 5 years of operation. Results from the first 5 years of operation include e.g.| budgets for energy| water and CO2| information on important but rarely occurring events such as evaporation from snow-covered canopies| and reactions of the forest to extreme drought. The carbon budget shows that the forest may be a sink of carbon although it is still growing. The completeness of the data has made it possible to test the internal consistency of SVAT models. The pioneering set-up at the CTS has been adopted by a large number of SVAT-monitoring sites around the world. Questions concerning tower maintenance| long-term calibration plans| maintenance of sensors and data-collection system| and continuous development of the computer network to keep it up to date are| however| only partly of interest as a research project in itself. It is thus difficult to get it funded from usual research-funding agencies. The full value of data generated by the CTS system can best be appreciated after a decade or more of continuous operation. Main uses of the data would be to evaluate how SVAT models handle the natural variability of climate conditions| quantification of water. carbon and energy budgets during various weather conditions| rind development of new parameterisation schemes in global and regional climate models. :(C) 1999 Elsevier Science B.V. All rights reserved.
2222,1999,4,4,Continuous long-term measurements of soil-plant-atmosphere variables at an agricultural site,It is a major challenge in modem science to decrease the uncertainty in predictions of global climate change. One of the largest uncertainties in present-day global climate models resides with the understanding of processes in the soil-vegetation-atmosphere-transfer (SVAT) system. Continuous| long-term data are needed to correctly quantify balances of water| energy and CO2 in this system and to correctly model them. It is the objective of this paper to demonstrate how a combined system of existing sensor| computer| and network technologies could be set up to provide continuous and reliable long-term SVAT-process data from an agricultural site under almost all weather conditions. A long-term climate-monitoring system within the framework of NOPEX was set up in 1993-1994 at the Marsta Meteorological Observatory (MMO). It is situated in a flat agricultural area where annual crops are cultivated on a heavy clay soil. It has successfully monitored relevant states and fluxes in the system| such as atmospheric fluxes of momentum| heat| water vapour and CO2| atmospheric profiles of wind speed| direction| and temperature| short- and long-wave radiation| soil temperature| soil-water contents| groundwater levels| and rainfall and snow depth. System uptime has been more than 90% for most of its components during the first 5 years of operation. Results from the first 5 years of operation has proven MMO to be an ideal site for intercomparison and intercalibration of radiometers and fast turbulence sensors| and for evaluation of other sensors| e.g.| rain gauges. The long time series of radiation data have been valuable to establish numerical limits for a set of quality-control flags. MMO has served as a boundary-layer research station and results from NOPEX campaigns show how the dimensionless wind gradient depends not only on the traditional stability parameter z/L but also on the height of the convective boundary layer. Measurements at the observatory grounds and a neighbouring field show a considerable variability in surface properties| which must be accounted for when assessing budgets of heat and other scalars. Questions concerning long-term calibration plans| maintenance of sensors and data-collection system| and continuous development of the computer network to keep it up to date are| however| only partly of interest as a research project in itself. It is thus difficult to get it funded from usual research-funding agencies. The full value of data generated by the: MMO system can best be appreciated after a decade or more of continuous operation. Main uses of the data would be to evaluate how SVAT models handle the natural variability of climate conditions| quantification of water| carbon and energy budgets during various weather conditions| and development of new parameterisation schemes in global and regional climate models. (C) 1999 Elsevier Science B.V. All rights reserved. 5131,1999,2,4,Covariability of aspects of north American climate with global sea surface temperatures on interannual to interdecadal timescales,Rotated canonical correlation analysis between seasonal- and longer-mean global SSTs and either U.S. surface temperatures or 700-hPa heights in the Pacific-North America region have led to decompositions into three distinct signals. One of these represents the interannual variability of ENSO and a second is related to the North Atlantic oscillation and exhibits considerable variability on interdecadal timescales. In contrast the temporal behavior of the third| which is referred to here as the global signal| is mostly characterized by a steady trend since the late 1960s. The robustness of this time series to variations in the analyses| as well as the robustness of the spatial structure of the SST pattern accompanying it| suggests that the decomposition represents a successful separation of the climate signal from the climate noise. When viewed in the context of other recent work| the global signal cannot be discounted as a "fingerprint" of global warming. Finally| calculations that exploit ensemble mean output from prescribed-SST GCM runs reveal notable systematic errors in the simulation of the features of all three signals. 2271,1999,2,4,Dam nation: A geographic census of American dams and their large-scale hydrologic impacts,Newly available data indicate that darns fragment the fluvial system of the continental United States and that their impact on river discharge is several times greater than impacts deemed likely as a result of global climate change. The 75|000 dams in the continental United States are capable of storing a volume of water almost equaling one year's mean runoff| but there is considerable geographic variation in potential surface water impacts. In some western mountain and plains regions| darns can store more than 3 year's runoff| while in the Northeast and Northwest| storage is as little as 25% of the annual runoff. Dams partition watersheds; the drainage area per dam varies from 44 km(2) (17 miles(2)) per dam in New England to 811 km(2) (313 miles(2)) per dam in the Lower Colorado basin. Storage volumes| indicators of general hydrologic effects of darns| range from 26|200 m(3) km(-2) (55 acre-feet mile(-2)) in the Great Basin to 345|000 m(3) km(-2) (725 acre-feet mile-2) in the South Atlantic region. The greatest river flow impacts occur in the Great Plains| Rocky Mountains| and the arid Southwest| where storage is up to 3.8 times the mean annual runoff. The nation's dams store 5000 m(3) (4 acre-feet) of water per person. Water resource regions have experienced individualized histories of cumulative increases in reservoir storage (and thus of downstream hydrologic and ecologic impacts)| but the most rapid increases in storage occurred between the late 1950s and the late 1970s. Since 1980| increases in storage have been relatively minor. 4927,1999,2,4,Deaths from heat-stroke in Japan: 1968-1994,Global warming is increasingly recognized as a threat to the survival of human beings| because it could cause a serious increase in the occurrence of diseases due to environmental heat during intermittent hot weather. To assess the direct impact of extremely hot weather on human health| we investigated heal-related deaths in Japan from 1968 through 1994| analyzing the data to determine the distribution of the deaths by age and their correlation to the incidence of hot days in summer. Vital Statistics of Japan| published by the Ministry of Health and Welfare of Japan| was the source of the heat-related mortality data employed in this study Meteorological data were obtained from the District Meteorological Observatories in Tokyo and Osaka| the two largest cities in Japan. Heat-related deaths were most prone to occur on days with a peak daily temperature above 38 degrees C| and the incidence of these deaths showed an exponential dependence on the number of hot days. Thus| even a small rise in atmospheric temperature may lead to a considerable increase in heat-related mortality| indicating the importance of combating global warming. Furthermore| half (50.1%) of the above-noted deaths occurred in children (4 years and under) and the elderly (70 years and over) irrespective of gender| indicating the vulnerability of these specific age groups to heat. Since a warmer climate is predicted in the future| the incidence of heat waves will increase| and more comprehensive measures| both medical and social| should be adopted for children of 4 years and younger the elderly to prevent heat-related deaths in these age groups. 5054,1999,2,4,Demography of the Yellowstone grizzly bears,We undertook a demographic analysis of the Yellowstone grizzly bears (Ursus arctos) to identify critical environmental factors controlling grizzly bear vital rates| and thereby to help evaluate the effectiveness of past management and to identify future conservation issues. We concluded that| within the limits of uncertainty implied by the available data and our methods of data analysis| the size of the Yellowstone grizzly bear population changed little from 1975 to 1995. We found that grizzly bear mortality rates are about double in years when the whitebark pine crop fails than in mast years| and that the population probably declines when the crop fails and increases in mast years. Our model suggests that natural variation in whitebark pine crop size over the last two decades explains more of the perceived fluctuations in Yellowstone grizzly population size than do other variables. Our analysis used demographic data from 202 radio-telemetered bears followed between 1975 and 1992 and accounted for whitebark pine (Pinus albicaulis) crop failures during 1993-1995. We used a maximum likelihood method to estimate demographic parameters and used the Akaike Information Criteria to judge the significance of various independent variables. We identified no independent variables correlated with grizzly bear fecundity. In order of importance| we found that grizzly bear mortality rates are correlated with season| whitebark pine crop size (mast vs. nonmast year)| sex| management-trapping status (never management-trapped vs. mangement-trapped once or more)| and age. The mortality rate of bears that were management-trapped at least once was almost double that of bears that were never management-trapped| implying a source/sink (i.e.| never management-trapped/management-trapped) structure. The rate at which bears move between the source and sink| estimated as the management-trapping rate (h)| is critical to estimating the finite rate of increase| <(lambda)over cap>. We quantified h by estimating the rate at which bears that have never been management-trapped are management-trapped for the first time. It differed across seasons| was higher in nonmast than mast years| and varied with age. We calculate that <(lambda)over cap> = 1.00 from 1975 to 1983 (four mast and five nonmast years) and 1.02 from 1984 to 1995 (seven mast and five nonmast years). Overall| we find that <(lambda)over cap> = 1.01 +/- 0.04 (mean +/- 1 SE) from 1975 to 1995. Our models suggest that future management should concentrate on the threats to white-bark pine| such as those posed by white pine blister rust| global warming| and fire suppression. As is currently widely recognized by Yellowstone land managers| our model also suggests that future management must compensate for the increased grizzly bear mortality that in likely to be caused by an increasing number of humans in Yellowstone. 4930,1999,2,4,Denitrification from fescue pastures in the southeastern USA fertilized with broiler litter,Many aspects of the denitrification process in pasture ecosystems remain poorly investigated| especially as affected by application of animal manures. Denitrification can be| however| a major pathway of N loss from soil| decreasing efficiency of N fertilizers| as well as contributing to global warming and ozone depletion. We quantified N loss via denitrification from tall fescue (Festuca arundinacea Schreb.) pastures following fertilization with broiler litter. Study sites were located in the Coastal Plain (Alabama)| Piedmont (Georgia)| and Cumberland Plateau (Tennessee) Major Land Resource Areas of the southeast USA. Litter was applied to supply 70 kg of available N hs-L based on equations developed by the USDA and the USEPA. Measurements were taken every 2 wk during the course of 2 yr (1995-1996 and 1996-1997) using an in-situ acetylene-inhibition technique. Denitrification flux was highly variable| ranging from -20 to 2500 mg N gas m(-2) h(-1). Total losses of N gas were all <6 kg ha(-1) during 150 d after application| representing a loss of <5% of total N applied. Losses from treated plots were not significantly; higher than those from control plots. Denitrification rates at these sites were not predictable by any one factor| but seemed to respond only to combinations of various factors such as soil temperature| soil NO(3) concentration| and soil|vater content. Our results indicate that risk of N loss and atmospheric pollution due to denitrification from soils in the southeastern USA is not significantly increased by application of broiler litter at appropriate rates. 4925,1999,2,3,Detectability of summer dryness caused by greenhouse warming,This study investigates the temporal and spatial variation of soil moisture associated with global warming as simulated by long-term integrations of a coupled ocean-atmosphere model conducted earlier. Starting from year 1765| integrations of the coupled model for 300 years were performed for three scenarios: increasing greenhouse gases only| increasing sulfate-aerosol loading only and the combination of both radiative forcings. The integration with the combined radiative forcings reproduces approximately the observed increases of global mean surface air temperature during the 20th century. Analysis of this integration indicates that both summer dryness and winter wetness occur in middle-to-high latitudes of North America and southern Europe. These features were identified in earlier studies. However| in the southern part of North America where the percentage reduction of soil moisture during summer is quite large| soil moisture is decreased for nearly the entire annual cycle in response to greenhouse warming. A similar observation applies to other semi-arid regions in subtropical to middle latitudes such as central Asia and the area surrounding the Mediterranean Sea. On the other hand| annual mean runoff is greatly increased in high latitudes because of increased poleward transport of moisture in the warmer model atmosphere. An analysis of the central North American and southern European regions indicates that the time when the change of soil moisture exceeds one standard deviation about the control integration occurs considerably later than that of surface air temperature for a given experiment because the ratio of forced change to natural variability is much smaller for soil moisture compared with temperature. The corresponding lag time for runoff change is even greater than that of either precipitation or soil moisture for the same reason. Also according to the above criterion| the inclusion of the effect of sulfate aerosols in the greenhouse warming experiment delays the noticeable change of soil moisture by several decades. It appears that observed surface air temperature is a better indicator of greenhouse warming than hydrologic quantities such as precipitation| runoff and soil moisture. Therefore| we are unlikely to notice definitive CO2-induced continental summer dryness until several decades into the 21st century. 4998,1999,2,3,Detecting the nonstationary response of ENSO to greenhouse warming,On the basis of the latest greenhouse warming experiment performed with the Max-Planck Institut coupled atmosphere/isopycnal ocean model (ECHAM4/OPYC) it is shown that not only the climate mean but also the statistics of higher-order statistical moments respond sensitively to greenhouse warming. In particular the Fl Nino-Southern Oscillation (ENSO) cycle obtains more energy| and a tendency toward cold events can be observed. These statistical changes are superimposed on an overall warming trend. It is suggested that this information can be used in order to refine climate change detection via the optimal fingerprinting strategy. An optimal spectral fingerprint is developed on the basis of linear perturbation theory of wavelet variances. In order to elucidate the potential of higher-order statistical moments in the climate change detection context the optimal spectral fingerprint technique is applied to the ECHAM4/OPYC greenhouse warming simulation. The results provide a rough estimate of the timescale over which human-caused changes in the statistics of ENSO can be expected to exceed the level of natural variability. These results reveal in particular that recent observed changes of ENSO variability are consistent with the null hypothesis of natural climate variability. Furthermore| an information theoretical approach is adopted to investigate possible influences of global warming on ENSO predictability. 4897,1999,2,4,Development of a new damage function model for power plants: Methodology and applications,Recent models have estimated the environmental impacts of power plants| but differences in assumptions and analytical methodologies have led to diverging findings. In this paper| we present a new damage function model that synthesizes previous efforts and refines components that have been associated with variations in impact estimates. Our model focuses on end-use emissions and quantifies the direct human health impacts of criteria air pollutants. To compare our model to previous efforts and to evaluate potential policy applications| we assess the impacts of an oil and natural gas-fueled cogeneration power plant in Boston| MA. Impacts under baseline assumptions are estimated to be $0.007/kWh of electricity| $0.23/klb of steam| and S0.004/ton-h of chilled water (representing 2-9% of the market value of outputs). Impacts are largely related to ozone (48%) and particulate matter (42%). Addition of upstream emissions and nonpublic health impacts increases externalities by as much as 50%. Sensitivity analyses demonstrate the importance of plant siting| meteorological conditions| epidemiological assumptions| a nd the monetary value placed on premature mortality as well as the potential influence of global warming. Comparative analyses demonstrate that our model provides reasonable impact estimates and would therefore be applicable in a broad range of policy settings. 5033,1999,3,4,Development of a semi-quantitative pre-LCA tool,This paper describes the development of a semi-quantitative pre-LCA (life-cycle assessment) tool for assessing the environmental impacts of the production of a printer. This tool provides a quick-and-easy means of assessing the environmental impacts of a complex product| where a full LCA evaluation of the complex product would often require extensive calculations and the analysis is very time-consuming and places a heavy burden on the designer. The tool allows a designer to easily compute a total environmental impact value for each of the various alternative designs. The pre-LCA tool computes an environmental impact value by considering factors such as airborne and waterborne emissions| the recyclability potential| waste disposal| the global warming factor| the energy content of raw materials| the divertible plastic waste potential| etc. The analytical hierarchy comparison method is used for the designers to indicate the relative importance of these factors with respect to their designs. Environmental values for the various factors are calculated from graphs that have been derived based on extensive interviews with engineers involved in the production process| as well as from literature research. (C) 1999 Elsevier Science S.A. All rights reserved. 4978,1999,3,3,Discounting the future - the cost of global warming,This essay begins by suggesting that although the ideas of Hegel appear more mystical and less practical than those of Adam Smith| both philosophies are nevertheless dependent on metaphysical assumptions. Smith's philosophical outlook finds its modern reflection in the notion of commensurability| the idea that social realities| amongst other things| can be indexed by a unitary measure of value. Economic cost-benefit analysis takes commensurability to its logical extreme by claiming that| for instance| the question whether to construct another London airport can be decided by applying it strict commercial analysis| attributing costs and prices to the whole range of environmental and human factors (but what value to place on a Norman church located in the path of the proposed runway?). A particularly intractable aspect of cost-benefit analysis is that| since any large investment project will almost certainly create benefits for some people and disbenefits for others| the analysis must include invidious interpersonal comparisons of utility - and while it might be equitable for those who benefit from such a project to compensate those who are disadvantaged by it| this in practice rarely happens. Finally| global warming due to the emission of greenhouse gases is examined| and it is shown how cost-benefit analysis applied to this situation turns out to be an even more complicated and an even less satisfactory approach. In conclusion it is suggested that| despite the insouciance of economists (which contrasts markedly with the anxieties of the climatologists and earth scientists)| the costs of our present rate of consumption of fossil fuels are bound to become enormous. 5036,1999,4,4,Dissolved organic carbon and nutrients as regulators of lake ecosystems: Resurrection of a more integrated paradigm,The primary interpretive paradigm used to study lakes is their trophic status. Oligotrophic lakes have low nutrient loading and low productivity| while eutrophic lakes have high nutrients and high productivity. The strong empirical relationship between nutrient loading and productivity is a Valuable tool for teaching| for research| and for management of lakes. In order to incorporate the variety of other known anthropogenic impacts on lakes| however| lake characterization needs to extend beyond the nutrient-productivity paradigm. For example| acid precipitation| heavy metal and toxic organic contaminants| increases in UV radiation| and global warming are all recognized threats to lake ecosystems. One of the key characteristics of lakes that determines how they respond to disturbances such as these is their concentration of colored dissolved organic carbon (CDOC). Here we argue that a paradigm that includes CDOC (using the absorption coefficient at 320 nm as a proxy) as well as nutrients will be useful in predicting and understanding the response of lake ecosystems to multiple stressors. We propose to resurrect the CDOC axis that was proposed by investigators earlier this century and to extend it by adding some operational definitions to permit placing some of the major lake types on the axes in a way that will help us to better understand the structure| function| and response to disturbance of lake ecosystems that are subject to natural and anthropogenic environmental changes at the local| regional| and global scales. Data from a few diverse lakes and a successional sequence in Glacier Bay| Alaska| are used to illustrate the potential utility of the 2-axis model in separating lake types. 5058,1999,2,4,Distribution and habitat use of the feral black rat (Rattus rattus) on subantarctic Macquarie Island,Macquarie Island is the southernmost limit to the distribution of the black rat Rattus rattus. The species was introduced to this subantarctic island by sealers during the 19th century. The rats are now widespread and abundant in coastal areas all around the island. The distribution of rat populations is divided into discrete units by the availability of suitable habitat which| in turn| is a consequence of the rugged topography| particularly on the west coast. Rats are found from almost sea level to 200-250 m a.s.l. and up to 1 km inland. They have adapted successfully to the rigorous climate and firmly occupy a habitat niche in an environment where food is plentiful| predators are few and interspecific competition minimal. The principal habitat| tall Poa foliosa tussock grassland| provides year-round shelter and food. Rats dig burrows in the peaty stools of the tussock plants and construct nesting chambers at the base of the dense leaf canopy. Predictably| this provides a warmer and more stable thermal environment than that experienced outside under the tussock canopy where the runs are located. Tussock grasslands are spreading under the influence of management control measures directed at the introduced European rabbit and possibly global warming. Management programmes are also directed towards the eradication of feral cats. In response| rat populations may be expected to expand in numbers and to occupy new territories. Without control this may| in the long term| have serious consequences for the island's avifauna| particularly the smaller| burrow-nesting species. 5037,1999,2,4,Disturbances of temperature-depth profiles due to surface climate change and subsurface water flow: 1. An effect of linear increase in surface temperature caused by global warming and urbanization in the Tokyo metropolitan area| Japan,A series of type curves is presented for evaluating vertical groundwater fluxes under the condition of a linear increase in surface temperature. The depths of minimum groundwater temperature in the temperature-depth profiles indicate the magnitude of the downward groundwater flux. The type curve method has been applied to the subsurface thermal regime observed in Tokyo metropolitan area| Japan| to estimate the vertical groundwater fluxes under the condition of surface warming caused by global warming and urbanization. The groundwater fluxes obtained from the type curves and the depths of minimum groundwater temperature agree well with the values obtained from the other studies in the Tokyo metropolitan area. The inversion due to the surface warming could be a good tracer to detect the groundwater flow system. 5062,1999,2,3,Do open-top chambers overestimate the effects of rising CO2 on plants? An analysis using spring wheat,The microclimate in facilities for studying effects of elevated CO2 on crops differs from ambient conditions. Open-top chambers (OTCs) increase temperature by 1-3 degrees C. If temperature and CO2 interact in their effect on crops| this would limit the value of OTC experiments. Furthermore| interaction of CO2 and temperature deserves study because increases in atmospheric CO2 concentration are expected to cause global warming. This paper describes two experiments in which a recently developed cooling system for OTCs was used to analyse the effects of temperature on photosynthesis| growth and yield of spring wheat (Triticum nestivum L.| cv. Minaret). Two levels of CO2 were used (350 and 700 ppm)| and two levels of temperature| with cooled OTCs being 1.6-2.4 degrees C colder than noncooled OTCs. Photosynthetic rates were increased by elevated CO2| but no effect of temperature was found. Cross-switching CO2 concentrations as well as determination of A-Ci curves showed that plant photosynthetic capacity after anthesis acclimated to elevated CO2. The acclimation may be related to the effects of CO2 on tissue composition: elevated CO2 decreased leaf nitrogen concentrations and increased sugar content. Calculations of the seasonal mean crop light-use efficiency (LUE) were consistent with the photosynthesis data in that CO2 increased LUE by 20% on average whereas temperature had no effect. Both elevating CO2 and cooling increased grain yield| by an average of 11% and 23%| respectively. CO2 and temperature stimulated yield via different mechanisms: CO2 increased photosynthetic rate| but decreased crop light interception capacity (LAI)| whereas cooling increased grain yield by increasing LAI and extending the growing season with 10 days. The effects of CO2 and temperature were not additive: the CO2 effect was about doubled in the noncooled open-top chambers. In most cases| effects on yield were mediated through increased grain density rather than increased individual grain weights. The higher growth response to elevated CO2 in noncooled vs. cooled OTCs shows that a cooling system may remove a bias towards overestimating crop growth response to CO2 in open-top chambers. 5101,1999,3,4,Dynamic externalities: Comparing conditions for Hopf bifurcation under laissez-faire and planning,Consider an economy described by two states. The first state describes a private stock subject to a firm's (or a consumer's) control| while the second state captures market interactions and is exogenous data to the individual firm. Considering rational expectations| a market equilibrium can be derived. This set-up is typical| in particular for the recently investigated new endogenous growth models. In contrast to the market outcome| planning attempts to internalise this externality. In both cases| the policies - either the optimal intertemporal policy of competitive firms exposed to this externality| or the social optimum - are characterised by a two-dimensional plane. Thus| complex solutions in particular limit cycles are possible. This paper compares the conditions of stability and| in particular| the conditions for limit cycles under these two different institutional set-ups| when the externality is or is not properly internalised. This comparison is first theoretical and then applied to a deliberately simple economic example: firms accumulate a capital stock (e.g.| sewage treatment| energy saving technologies) involving convex investment costs and this stock lowers emissions (or kinds of waste) that add to a stock of pollution (e.g. global warming| pollution of water and soil| etc.). 2223,1999,2,4,Dynamics of a toxic cyanobacterial bloom (Cylindrospermopsis raciborskii) in a shallow reservoir in the semi-arid region of northeast Brazil,The species composition and the seasonal succession of phytoplankton were analyzed in a eutrophic drinking water reservoir located in the semi-arid region of northeast Brazil. Investigations were based on bimonthly or monthly sampling over 2 yr (1997 to 1998) conducted at 1 representative station with 2 sampled depths (0.5 and 5 m near the bottom). Limnological parameters (temperature| pH| dissolved oxygen| conductivity| light| dissolved inorganic nutrients) were simultaneously measured to determine the possible factors affecting the phytoplankton composition. We determined 30 taxa during the survey which were numerically dominated by the class Chlorophyceae. However| both in terms of abundance and biomass| Cyanobacteria dominated the phytoplankton community with Cylindrospermopsis raciborskii (Wolsz.) Seenayya et Subba Raju. This species can represent biomass close to 96-100% of total phytoplankton biomass| with values reaching 70 mg l(-1) (fresh weight) between April and November 1998. Over the survey| the filaments of C. raciborskii were coiled (average of 97%) with a mean proportion of 12.3% of terminal heterocytes. The species toxicity was determined from bioassay analysis and the presence of neurotoxins was revealed during the bloom. By March 1998| chlorophyll concentration reached 135 mu g l(-1) at the surface level| inducing a sharp decrease of the euphotic zone depth. Favorable environmental conditions were observed for the bloom with high temperatures| high pH| low N/P ratio| and absence of efficient predators. The nutrient context seemed to play a role in the cyanobacterial bloom despite the absence of external nutrient supply. However| annual rain deficit and lack of water renewal in 1998 linked to the 1997 EI Nino consequences seem to be the major factors responsible for both hypereutrophic conditions and cyanobacterial blooms in the reservoir studied. Thus| global climate change can influence phytoplankton population dynamics in continental waters| as demonstrated frequently in oceanic ecosystems. 2277,1999,5,4,Early-Holocene aridity in tropical northern Australia,Thermoluminescence ages from a longitudinal dunefield in tropical northern Australia suggest that complete dune activation occurred here either continuously or sporadically between approximately 8.2 ka and 5.9 ka. This period| in Australia| is normally ascribed to one of increasingly warm and wet conditions towards the Holocene Climatic Optimum. However| elsewhere| this time (similar to 8 ka) coincides with a brief period of global climate change recognized in O-18 records From Antarctica| methane records of the Greenland Summit ice cores| changes to deep-sea benthic foraminferal composition and atmospheric C-14 variations. Tn tropical Africa two distinct phases of aridity have been dated at approximately 8 ka and 6 ka. The coincidence of aeolian reactivation episodes in this north Australian dunefield with brief phases of early-Holocene climate change elsewhere suggests possible global climatic teleconnections at this time. 4896,1999,4,2,Earth's future climate,The enhanced greenhouse effect. The Earth's surface temperature is slowly rising due to human activities| which are releasing heat-trapping gases| notably carbon dioxide and methane. into the atmosphere. By 2100 this temperature rise is expected to reach 2 +/- 1 degrees C| other climatic influences remaining constant. This will be the fastest rate of climate change the Earth has experienced since the start of modern civilization 10 000 years ago. (Figure from Pringle (1988)| used with permission of Hodder and Stoughton Limited.) Climate change occurs on time-scales ranging from annual changes associated with El Nino. through decadal changes| to multidecadal trends linked to global warming. It affects us all in our daily lives| impacts the performance of much of industry| and leads to billions of pounds of damage worldwide each year. In many countries the general public is becoming concerned as press reports| personal experience and anecdotal information all point to an increase in the frequency and severity of extreme weather events linked to climate change. Many opinions have been expressed on the subject from the doomladen to the dismissive. This paper aims to state clearly the current scientific position on cBmate change| and to provide informed scientific projections for Earth's climate into the next millennium. This will help decision makers| managers of weather risk| and all with an interest in our future climate. 2282,1999,2,4,Ecological and socioeconomic impacts of 1998 coral mortality in the Indian Ocean: An ENSO impact and a warning of future change?,The year 1998| was the warmest year since the start of temperature recordings some 150 years ago. Similarly| the 1990s have been the warmest decade recorded. In addition| 1998 saw the strongest El Nino ever recorded. As a consequence of this| very high water temperatures were observed in many parts of the oceans| particularly in the tropical Indian Ocean| often with temperatures of 3 degrees to 5 degrees C above normal. Many corals in this region bleached and subsequently died| probably due to the high water temperatures in combination with meteorological and climatic factors. Massive mortality occurred on the reefs of Sri Lanka| Maldives| India| Kenya| Tanzania| and Seychelles with mortalities of up to 90% in many shallow areas. Reefs in other parts of the Indian Ocean| or in waters below 20 m| coral mortality was typically 50%. Hence| coral death during 1998 was unprecedented in severity. The secondary socioeconomic effects of coral bleaching for coastal communities of the Indian Ocean are likely to be long lasting and severe. In addition to potential decreases in fish stocks and negative effects on tourism| erosion may become an acute problem| particularly in the Maldives and Seychelles. If the observed global trends in temperature rises continue| there will be an increased probability of a recurrence of the phenomenon observed in 1998 on the coral reefs of the Indian Ocean| as well as in other parts of the tropical oceans in coming years. Coral reefs of the Indian Ocean may prove to be an important signal of the potential effects of global climate change| and we should heed that warning. 4908,1999,4,4,Ecological basis of Alpine meadow ecosystem management in Tibet: Haibei Alpine Meadow Ecosystem Research Station,Alpine meadow and shrub are the main pasture types on the Tibetan Plateau| and they cover about 35% of the total land area. In order to understand the structural and functional aspects of the alpine ecosystem and to promote a sustainable animal production system| the Haibei Alpine Meadow Research Station was established in 1976. A series of intensive studies on ecosystem structure and function| including the energy flow and nutrient cycling of the ecosystem| were the main tasks during the first 10 years. Meanwhile| studies with 5 different grazing intensities on both summer and winter pasture have been conducted. In the early years of the 1990s| the research station started to focus its research work on global warming| biodiversity and sustainable animal production systems in pastoral areas. Various methods for improving degraded pasturelands have been developed in the region. 2302,1999,4,2,Econometric analysis of global climate change,This paper reports on research that applies econometric time series methods to the analysis of global climate change. The aim of this research was to test hypotheses concerning the causes of the historically observed rise in global temperatures. Longer term applications include quantification of the contribution of different forcing variables to historic warming and use of the model as a module in integrated assessment. Research to date has comprised three stages. In the first stage we used the concept of Granger causality and differences between the temperature record in the northern and southern hemispheres to investigate the causes of temperature increase. In the second stage we tested various global change time series for the presence of stochastic trends. We found that most series contain a stochastic trend with the greenhouse gas series containing I(2) stochastic trends. In the third stage we developed a structural time series to investigate some of the hypotheses suggested by the earlier stages and further tested for the presence of an I(2) trend in hemispheric temperature series. We found that the two temperature series share a common I(2) stochastic trend that may have its source in radiative forcing due to greenhouse gases. There is a second non-stationary component that appears only in the northern hemisphere and appears to be related to radiative forcing due to anthropogenic sulphur emissions. (C) 1999 Elsevier Science Ltd. All rights reserved. 5056,1999,5,4,Effect of Permo-Carboniferous climate on illite-smectite| Haushi Group| Sultanate of Oman,The Late Westphalian to Artinskian Haushi Group in the Sultanate of Oman consists of the glaciogenic Al Khlata Formation and the Gharif Formation which contains marginal marine| coastal plain| and fluvial sediments. The sequence was deposited during a global-warming event following the Permo-Carboniferous glaciation of Gondwana. Because of a varied subsidence history| these sediments range from the surface in thr SE to almost 5000 m in the NW of the basin. Mixed-layer illite-smectite (I-S) is an important constituent of the <2 mu m size fraction of sandstone and shale samples in both formations at all depths. Different starting compositions lead to three distinct trends of illite layers in I-S versus temperature for different sedimentary environments and paleoclimatic conditions. The starting compositions of I-S at the surface range from an ordered I-S in the Al Khlata Formation to smectite-rich in the Upper+Middle Gharif members. Physical| chemical and environmental factors were investigated as causes for the different starting compositions of T-S. Both formations share an identical burial history| paragenesis| thermal evolution| and source of detrital material. They differ only in environmental conditions during sedimentation. Thus| the variation in starting composition of I-S appears to be best explained by distinct weathering conditions during sedimentation of the three units. Ln particular. the expected low intensity of chemical weathering during glaciogenic conditions is marked by the presence of higher amounts of unstable volcanic and sedimentary rock fragments in the Al Khlata Formation. 4980,1999,3,4,Effect of satellite bubbles on dynamics of gas absorption from a CO2 bubble into a downward-flowing liquid,The dynamic process of gas absorption from a CO2 bubble into a liquid is examined in the presence of satellite bubbles. The bubble under consideration is held stationary| except its jittering| by the liquid flowing downward. The mass transfer rate is determined by monitoring the rate of reduction in the equivalent bubble diameter during the initial absorption process. It is found that the interaction with the satellite bubbles generally hampers the dissolution of the primary bubble. The extent of reduction in the dissolution rate increases with the net contacting time during the interaction. When the secondary bubbles interact with the primary bubble mainly outside of its wake| however| the dissolution tends to be enhanced due to induced turbulence in the surrounding liquid flow. A simple theoretical model is developed to simulate the observed results aii well as the basic features prevailing in a recently proposed scheme| called the GLAD system| for shallow injection of CO2 gas into seawater. 2279,1999,2,3,Effect of temperature on humus respiration rate and nitrogen mineralization: Implications for global climate change,Respiration and nitrogen mineralization rates of humus samples from 7 Scots pine stands located along a climatic transect across the European continent from the Pyrenees (42 degrees 40') to northern Sweden (66 degrees 08') were measured for 14 weeks under laboratory conditions at temperatures from 5 degrees C to 25 degrees C. The average Q(10) values for the respiration rate ranged from about 1.0 at the highest temperature to more than 5 at 10 degrees C to 15 degrees C in the northernmost samples. In samples from more northern sites| respiration rates remained approximately constant during the whole incubation period; in the southern end of the transect| rates decreased over time. Respiration rate was positively correlated with incubation temperature| soil pH and C:N ratio| and negatively with soil total N. Regressions using all these variables explained approximately 71% of the total variability in the respiration rate. There was no clear relation between the nitrogen mineralization rate and incubation temperature. Below 15 degrees C the N-mineralization rate did not respond to increasing temperature; tit higher temperatures| significant increases were found for samples from some sites. A regression model including incubation temperature| pH| N-tot and C:N explained 73% of the total variability in N mineralization. The estimated increase in annual soil respiration rates due to predicted global warming at the high latitudes of the Northern Hemisphere ranged from approximately 0.07 x 10(15) to 0.13 x 10(15) g CO2 at 2 degrees C and 4 degrees C temperature increase scenarios| respectively. Both values are greater than the current annual net carbon storage in northern forests| suggesting a switch of these ecosystems from net sinks to net sources of carbon with global warming. 4942,1999,4,3,Effective thermal conduction model for estimating global warming,This paper presents a simple way to approximate the dependence of the global mean air temperature at Earth's surface on the atmospheric concentration of carbon dioxide. It treats the atmosphere as a blanket| the effective thermal conductivity of which is a decreasing function of the amount of CO2 present| and does not involve the details of energy transport. The only data required are the CO2 concentrations at the middle of the nineteenth and the end of the twentieth centuries| and the shift in temperature that has occurred over that time. This elementary| phenomenological energy-balance approach is well suited for undergraduate physics courses to illustrate thermal conduction and radiation| by way of the very interesting and critically important example of greenhouse warming of Earth. (C) 1999 American Association of Physics Teachers. 4955,1999,2,3,Effects of climate change and nitrogen deposition on the carbon sequestration of a forest ecosystem in the boreal zone,Global warming and nitrogen deposition are expected to modify the carbon sequestration of boreal forests| causing feedback to atmospheric CO2 and climate. The objective of this study was to assess the effects of climate change and various N deposition rates on C sequestration of a forest ecosystem. The study uses a gap-type forest model for a managed Scots pine (Pinus sylvestris L.) stand in conditions representing southern Finland. Model computations indicated that| for both current and changed (+4 degrees C and +10% in precipitation) climatic conditions| increased levels of N deposition from 6 to 12 kg.ha(-1) per year increased C uptake by 4-6.5%. Total C stock (vegetation| litter| and soil organic matter) was 11% higher for current level of N deposition than without deposition. Changed climate resulted in a 10% higher C stock of the vegetation but 30% lower C stock in the forest soil. Consequently| the total C stock in forests was decreased because of the greater decline in soil C stock. The combined effects of climate change and N deposition decreased the average C stock of forest (over a 100-year rotation period) with annual deposition rates under 12 kg N.ha(-1) but slightly increased C stock with deposition of 24 kg N.ha(-1). 2224,1999,2,4,Effects of enhanced UV-B radiation on a weedy forb (Plantago lanceolata) and its interactions with a generalist and specialist herbivore,Assessments of potential impacts of global climate change often focus exclusively on plants; however| as the base of most food webs| plants generally experience abiotic stresses concomitantly with biotic stresses. Longleaf plantain| Plantago lanceolata L.| is a cosmopolitan temperate perennial weed that experiences a wide range of environmental conditions throughout its range. We examined the impacts of elevated levels of exposure to shortwave (UV-B) radiation on this plant| on two herbivores associated with this plant| and on the plant-herbivore interaction. Plantains were grown at 6 and 12 kJ m(-2) d(-1) BE300 UV-B radiation and concentrations of iridoid glycosides (aucubin and catalpol)| verbascosides| and nitrogen were measured. In terms of plant impacts| we found that iridoid glycoside concentrations were unchanged by elevated UV-B radiation| whereas| in one experiment| the concentration of verbascosides in young leaves and levels of nitrogen in old leaves increased under elevated UV-B radiation. Variation in plant chemistry due to leaf age and maternal family was greater than variation due to UV-B exposure. When caterpillars were fed excised leaves from plants grown under elevated UV-B| growth and survivorship of the specialist herbivore| Precis coenia Hbn. (Lepidoptera: Nymphalidae)| were unaltered and growth of the generalist herbivore| Trichoplusia ni (Hbn.) (Lepidoptera: Noctuidae)| was accelerated. When the caterpillars were reared on potted plants at high and low levels of UV-B radiation| growth and survivorship of P. coenia were unchanged while growth of T. ni was significantly depressed by elevated UV-B. Elevated UV-B altered allocation patterns of above-ground biomass in these plants; masses of crowns and reproductive tissue were reduced. UV-B levels| however| did not affect distribution of damage to foliage inflicted by either species. In two additional experiments with artificial diet| designed to test the direct effect of UV-B radiation on caterpillars| growth and survivorship of P. coenia were unaltered while survivorship of T. ni was significantly depressed when caterpillars were exposed to elevated UV-B radiation. These studies collectively demonstrate that higher trophic level impacts of UV-B-induced changes in plants depend on the identity of the herbivore and its degree of adaptation not only to variation in hostplant quality but also variation in its light environment. 4935,1999,2,4,Effects of global warming on nematode diversity in a Swedish tundra soil - a soil transplantation experiment,The implications of global warming on nematode populations were studied in a soil transplantation experiment. Blocks of peat from an ombrotrophic mire at Abisko| northern Sweden| were transplanted to nine warmer sites in Sweden in June 1996. The changes in nematode abundance and species composition were followed by monthly samplings from July to December 1996 with a final sampling in June 1997. In all sites except the most northern the total nematode numbers increased during the study period. However| especially at the three northern-most sites the composition of the nematode fauna changed very little. Most species from the mire survived in all transplants and the number of immigrating species was low. The most clearcut effects on faunal composition were seen in blocks transferred to open sites in central and southern Sweden. This was also indicated by the Maturity index (sensu Bongers) and Renkonen numbers (comparing similarity in fauna structure between source sire and transplantation sites). These parameters had the lowest values in blocks placed in the exposed sites where the greatest fluctations in temperature and moisture occurred. One conclusion of the study is that a climatic change has no rapid influence on the composition of the nematode fauna: soil structure and vegetation have a stronger influence. If the soil structure and vegetation start to change this will certainly also influence the nematode fauna. Upon warming above certain temperature thresholds| expected changes would result in an increased rate of mineralization followed by higher abundance of fungal and bacterial feeders belonging to the Secernentea. 4988,1999,2,4,Effects of temperature and natural disturbance on growth| reproduction| and population density in the alpine annual hemiparasite Euphrasia frigida,The effects of temperature and "natural disturbance" on growth| seed production| and population density in the facultative hemiparasitic annual Euphrasia frigida (Scrophulariaceae) were examined in the middle alpine zone at Finse| southwest Norway. Experimentally elevated temperature increased growth and seed production significantly. Higher temperatures resulted in a small decrease in population densities during three seasons. The degree of "natural disturbance" did not influence growth and seed production| but population density was highest at intermediate disturbance levels. Thus| while temperature influenced the performance of E. frigida| disturbance affected the population dynamics. The effects of temperature on growth and reproduction may also be indirect on hemiparasites| through improved conditions for the host plants under elevated temperatures. It is hypothesized that the predicted global warming will result in increased seed output from E. frigida plants in the middle alpine zone. Population densities| however are likely to decrease under elevated temperatures| due to lower disturbance levels by frost heave and increased vegetation cover. 5010,1999,2,4,Effects of temperature on stem nematode (Ditylenchus dipsaci) infestation of white clover (Trifolium repens) swards,Development of stem nematode (Ditylenchus dipsaci) infestations of white clover (Trifolium repens) in artificially established swards and transplanted turfs was monitored at field sites with different mean daily temperatures. In artificial swards the level of nematode infestation was inversely related to mean daily temperature. In transplanted turfs| nematodes caused a 46% reduction in white clover density over an 18-month period; the level of damage was not significantly affected by mean daily temperature although the proportion of clover stolons infested was higher at colder temperatures. Reductions in infestation levels at higher temperatures are probably the result of reduced survival in soil and the upper lethal temperature for nematodes being exceeded more frequently under warmer conditions. 5083,1999,2,4,Effects of water temperature on protein synthesis and protein growth in juvenile Atlantic wolffish (Anarhichas lupus),The effects of water temperature (5| 8| 11| and 14 degrees C) on the fractional rate (percent per day) of protein consumption (k(r)) and on white muscle and whole-body fractional rates of protein synthesis (k(s))| protein growth (k(g))| and growth efficiency (PPV| growth/consumption; k(g)/k(s)| growth/synthesis) of juvenile Atlantic wolffish (Anarhichas lupus) (initial body weight 26 g) were studied. Rates of protein consumption and white muscle and whole-body protein synthesis increased in a linear fashion between 5 and 14 degrees C. In contrast| the relationships between temperature and white muscle and whole-body protein growth| protein growth efficiency (PPV) and protein synthesis retention efficiency (k(g)/k(s)) were parabolic. The results indicated that the optimum water temperatures for growth (T-opt.G) and growth efficiency (T-opt.GE) were 10-11 and 9-10 degrees C| respectively The maximum white muscle and whole-body protein growth rates recorded at T-opt.G were 0.9 and 0.7 %.day(-1)| respectively. At T-opt.GE| the maximum white muscle and whole-body PPV values were 28 and 34%| respectively| and k(g)/k(s) values were 92 and 51%| respectively. The growth performance data for juvenile Atlantic wolffish in comparison with published data for salmonids (rainbow trout (Oncorhynchus mykiss)| Atlantic salmon (Salmo salar)) at 9-11 degrees C further highlight its suitability as an alternative species for cold-water aquaculture in northern Europe and Atlantic Canada. 5127,1999,3,4,Electricity generating renewables and global warming emissions,It is sometimes assumed that renewable technologies which emit carbon dioxide (CO2) in their operation do not offset CO2 emissions as much as technologies such as wind energy| PV or hydro. Firstly this paper examines the CO2 savings achieved by electricity generated from renewables as a result of their being substituted for fossil fuel-fired generation. These savings are then balanced against the CO2 emissions arising from the manufacture of the power plant and in the case of some technologies| the CO2 produced in operation. The end result for all technologies is a net CO2 saving.
Some renewable energy technologies also reduce methane emissions. These methane emission savings are converted into CO2 equivalents to give a measure of the net global warming reduction effect of generating electricity from these sources. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
Because of their understanding of climate changes during the geological past geoscientists can make important contributions to the evaluation of the current climate scenario. The climate factors that are actually decisive| such as changes in solar energy| which have substantially characterized the temperatures prevailing on the earth and continue to determine them| cannot be controlled by man. Impacts introduced by anthropogenic influences| such as the input of climatically relevant gases into the atmosphere| represent the only possibility of intervention even though the effects of countermeasures on the climate are bound to remain slight. In view of the relatively minor effects that anthropogenic carbon dioxide has had| and will presumably continue to have| on the climate scenario it must be wondered whether the considerable effort expended on countermeasures is always justifiable from an economic point of view. In spite of this| the consumption of fossil fuels| and thus the emission of carbon dioxide| must be kept as low as possible for reasons of environmental protection and the preservation of raze materials. The BGR (Federal Institute for Geosciences and Raw Materials) suggests that these findings should be incorporated in the arguments put forward by policy makers when decisions on industrial development and global warming prevention are made| so that the dialogue between economic and ecological interests can yield sensible and environmentally compatible solutions at reasonable cost. The inclusion of| and even closer cooperation between| neo-climatology| which focuses on the more recent past| and palaeo-climate research| which applies geoscience to reconstruct climatological data| is creating an enhanced basis for future climate forecasts. Sudden and severe climate changes| the reasons for which have not been determined to date| are known to have occurred within one decade in prehistoric times. The justified question about forecasting short- and medium-term climate changes cannot yet be answered by reliable model predictions. In the long run| however| astronomic and geoscientific findings suggest a temperature drop over the next 10 000 years.
2266,1999,2,4,Global and local implications of biotechnology and climate change for future food supplies,The development of improved technology for agricultural production and its diffusion to farmers is a process requiring investment and time. A large number of studies of this process have been undertaken. The findings of these studies have been incorporated into a quantitative policy model projecting supplies of commodities (in terms of area and crop yields)| equilibrium prices| and international trade volumes to the year 2020| These projections show that a "global food crisis|" as would be manifested in high commodity prices| is unlikely to occur. The same projections show| however| that in many countries|"local food crisis|" as manifested in low agricultural incomes and associated low food consumption in the presence of low food prices| will occur. Simulations show that delays in the diffusion of modern biotechnology research capabilities to developing countries will exacerbate local food crises. Similarly| global climate change will also exacerbate these crises| accentuating the importance of bringing strengthened research capabilities to developing countries. 2292,1999,2,4,Global and local threats to coral reef functioning and existence: review and predictions,Factors causing global degradation of coral reefs are examined briefly as a basis for predicting the likely consequences of increases in these factors. The earlier consensus was that widespread but localized damage from natural factors such as storms| and direct anthropogenic effects such as increased sedimentation| pollution and exploitation| posed the largest immediate threat to coral reefs. Now truly global factors associated with accelerating Global Climate Change are either damaging coral reefs or have the potential to inflict greater damage in the immediate future: e.g. increases in coral bleaching and mortality| and reductions in coral calcification due to changes in sea-water chemistry with increasing carbon dioxide concentrations. Rises in sea level will probably disrupt human communities and their cultures by making coral cays uninhabitable| whereas coral reefs will sustain minimal damage from the rise in sea level. The short-term (decades) prognosis is indeed grim| with major reductions almost certain in the extent and biodiversity of coral reefs| and severe disruptions to cultures and economies dependent on reef resources. The long-term (centuries to millennia) prognosis is more encouraging because coral reefs have remarkable resilience to severe disruption and will probably show this resilience in the future when climate changes either stabilize or reverse. 2304,1999,2,3,Global change: state of the science,Only recently| within a few decades| have we realized that humanity significantly influences the global environment. In the early 1980s| atmospheric measurements confirmed basic concepts developed a decade earlier. These basic concepts showed that human activities were affecting the ozone layer. Later measurements and theoretical analyses have clearly connected observed changes in ozone to human-related increases of chlorine and bromine in the stratosphere. As a result of prompt international policy agreements| the combined abundances of ozone-depleting compounds peaked in 1994 and ozone is already beginning a slow path to recovery. A much more difficult problem confronting humanity is the impact of increasing levels of carbon dioxide and other greenhouse gases on global climate. The processes that connect greenhouse gas emissions to climate are very complex. This complexity has limited our ability to make a definitive projection of future climate change. Nevertheless| the range of projected climate change shows that global warming has the potential to severely impact human welfare and our planet as a whole. This paper evaluates the state of the scientific understanding of the global change issues| their potential impacts| and the relationships of scientific understanding to policy considerations. (C) 1999 Elsevier Science Ltd. All rights reserved. 2245,1999,2,2,Global climate change,Climate| the statistical description of weather including the probabilities for anomalies| changes continuously| since both the interaction among the climate system components (atmosphere| ocean| biosphere| cryosphere| and lithosphere) and the irradiance of the sun vary on all timescales up to billions of years. On timescales which are of most interest for mankind| i.e. up to centuries| major factors causing climate variability are: changing composition of the atmosphere; spectral solar irradiance variations; systematic changes of ocean-atmosphere-land interaction| if resulting in major changes of ocean circulation; volcanic eruptions injecting mass into the low latitude stratosphere (>20 km height); and land cover change modifying the surface energy budget. Two of these influencing factors are now largely anthropogenic| namely changing atmospheric conditions and land cover change. Thus| the climate discussion has become to a large extent one about anthropogenic influence. At different periods| different influencing factors have been more important or dominant. Since the complex interactions are only partly understood| it is difficult to attribute observed climate parameter changes or trends to particular causes. In this brief status report on global climate change| present knowledge is reviewed| mainly based on the second full assessment report of the Intergovernmental Panel on Climate Change. 2248,1999,5,4,Global climate change,Most of the last 100|000 years or longer has been characterized by large| abrupt| regional-to-global climate changes. Agriculture and industry have developed during anomalously stable climatic conditions| New| high-resolution analyses of sediment cores using multiproxy and physically based transfer functions allow increasingly confident interpretation of these past changes as having been caused by "band jumps" between modes of operation of the climate system. Recurrence of such band jumps is possible and might be affected by human activities. 2255,1999,4,4,Global climate change and accuracy of prediction of species' geographical ranges: establishment success of introduced ladybirds (Coccinellidae| Chilocorus spp.) worldwide,Aim Predictions of how the geographical ranges of species change implicitly assume that range can be determined without invoking climate change. The aim here was to determine how accurate predictions of range change might be before entertaining global climatic change. Location Worldwide. Methods All the documented global biological control translocations of ladybirds (Coccinellidae: Chilocorus spp.) were analysed with the ecoclimatic program| CLIMEX. This program determines species distributions in relation to climate| and can be used to express the favourableness of different localities for a species. CLIMEX is also a useful exploratory tool for determining the likelihood of establishment of species introduced from one area to another. Results Predictive models were developed based on the likelihood of establishment of fifteen Chilocorus spp. relative to their physiological characteristics and climatic tolerances. This likelihood was compared with actual establishment with a resultant range of 0% accuracy to 100% accuracy. Only four (26.7%) species climatic tolerances could the predicted with 100% certainty. The general lack of accurate prediction was because climate is not always the overriding feature determining whether a species will establish or not. Other determinants| such as localized response to microclimate| phenology| host type and availability| presence of natural enemies and hibernation sites play a varying role over and above climate in determining whether a species will establish at a new locality. Main conclusions This study shows that even in the absence of climate change| range cannot always be determined| which means that most predictions of range change with climate change are likely to be wrong. 2235,1999,2,2,Global climate change| rice productivity and methane emissions: comparison of simulated and experimental results,Irrigated rice production is a major food source for a large portion of the world's population| and a major anthropogenic source of the greenhouse gas methane (CH4). Potential impacts of global climate change [elevated carbon dioxide (CO2) and/or elevated temperature] on rice can be predicted with simulation models| but experiments are necessary to determine how well these models mimic the responses of the field crop. This paper compares grain yield| biomass| and methane emissions from experiments at the international Rice Research Institute (IRRI) at Los Banos| the Philippines| with potential responses based on simulations using the ORYZA1 process model and the climate data from those experiments. Yield and biomass were compared for the 1995 and 1996 dry seasons (DS) and the 1994 wet season (WS). Emissions of CH4 from rice fields were evaluated for the 1995 WS and 1996 DS| Simulated and experimental responses (adjusted for effects of the open-top chambers on plant growth) differed with climate change scenario| response parameter| and season Under current climate conditions (ambient CO2 and ambient temperature)| simulated grain yield was 14% lower than the adjusted experimental grain yield in the 1996 DS| but was 17 and 37% higher than experimental grain yield in the 1995 DS and 1994 WS| respectively. With current climate| simulations underestimated experimental aboveground| belowground| and total biomass. The simulated CH4 emissions were the same as the experimental emissions| assuming CH4 emissions were 2.9% of the simulated total biomass carbon. With elevated CO7 and ambient temperature| simulations predicted greater increases (compared with current climate) in grain yield| aboveground biomass| and total biomass| but generally smaller increases in belowground biomass and CH4 emissions than the significant (at p < 0.05) increases that were found experimentally. With ambient CO2 and elevated temperature| both simulations and experiments generally showed either no change or a decrease in grain yield and biomass| but none of the responses in the experiments wen statistically significant. Simulated ambient CO2 and elevated temperature resulted in a smaller decrease in CH4 emissions than the significant decrease found in the experiments. For both elevated CO2 and elevated temperature| simulated grain yield increased in all three seasons| whereas there were no significant effects on experimental grain yield. The simulations predicted smaller increases in belowground biomass and CH4 emissions with elevated CO2 and elevated temperature than the significant increases in the experiments. To better correspond to experimental results| this study suggested that current simulation models could be improved in terms of effects of temperature on grain yield and use of belowground biomass to estimate CH4 emissions. (C) 1999 Elsevier Science B.V. All rights reserved. 2268,1999,2,4,Global climate change: Why US insurers care,The number of natural catastrophes in this decade is four times greater than in the 1960s; economic losses are eight times greater; and insured losses are 15 times greater. The insurance industry's financial interest is inter-dependent with climate and weather. Natural events drive the demand for insurance coverage and can threaten the viability of an insurer if it is over-exposed in high risk areas. Early in the 1990s| the industry began to recognize that historical data were potentially misleading with respect to future natural catastrophe exposure. The U. S. insurance industry is pursuing a variety of new approaches including: the use of catastrophe computer models to integrate the natural knowledge about extreme events taken from the sciences into the actuarial sciences. The evaluation of building codes and building code enforcement in every community in the country enhanced its support for hazard mitigation. 4996,1999,3,3,Global CO2 recycling - novel materials and prospect for prevention of global warming and abundant energy supply,CO2 emissions which induce global warming| increase with the growth of the economic activity. It is| therefore| impossible to decrease emissions only by energy savings and by improvements of the energy efficiency. Global CO2 recycling can solve this problem and supply abundant renewable energy. Global CO2 recycling consists of three districts: (i) in deserts| all necessary electricities are generated by solar cells; (ii) on coasts close to the deserts| the electricity is used for production of H-2 by seawater electrolysis| H-2 is converted to CH4 by the reaction with CO2 and liquefied CH4 is transported to energy consuming districts; (iii) at energy consuming district| after CH4 is used as a fuel| CO2 is recovered| liquefied and transported to the coasts close to the deserts. A CO2 recycling plant for substantiation of our idea has been built on the roof of our Institute (IMR) in 1996| using key materials tailored by us. The key materials necessary for global CO2 recycling are the anode and cathode for seawater electrolysis and the catalyst for CO2 methanation. Since the quantities of CO2 to be converted far exceed an industrial level| the system must be very simple and the rate of conversion must be very fast. These requirements are satisfied in our global CO2 recycling system. When global CO2 recycling is conducted on a large scale| the energies and costs required to form liquefied CH4 in our global CO2 recycling system are almost the same as those for production of LNG from natural gas wells. A project for field experimenting the global CO2 recycling using pilot plants in Egypt has been planned in cooperation with Egyptian scientists| engineers and industries. (C) 1999 Elsevier Science S.A. All rights reserved. 4990,1999,3,4,Global passenger travel: implications for carbon dioxide emissions,Humans spend| on average| a constant fraction of their time and expenditure on travel. These and a few other constraints allow a new model for projecting regional and world travel| which we use to develop a scenario for carbon emissions from passenger transport. Globally| carbon emissions rise from 0.8 GtC in 1990 to 2.7 GtC in 2050. In every industrialized region aircraft and high-speed trains become the dominant mode; unable to satisfy the rising demand for mobility within a fixed travel time budget| automobile travel declines by 2050. Passenger transport carbon emissions stabilize by 2020 without any further policy intervention. But in developing countries automobile travel is still rising and becomes the dominant source of carbon dioxide from passenger transport. Fear of global warming may require stabilization of these emissions by mid-century| We show that without some action to accelerate an improvement in energy efficiency starting in the next decade| the goal of stabilization is a technically impossible task| unless zero-carbon technologies become available. (C) 1999 Elsevier Science Ltd. All rights reserved. 4999,1999,2,4,Global warming - Organisms feel the heat,Feeling the heat: Studies in different regions of the world reveal the biological effects of climate change global warming. 4936,1999,4,4,Global warming - Solar variability and the Earth's climate,Lockwood et al.1 recently presented some intriguing new evidence of solar variability| but Parker's accompanying News and Views article2 gave an exaggerated and misleading picture of the potential effects on terrestrial climate. This picture is at variance with both the evidence3 and a public statement by Lockwood himself| reported in ref. 4. 5049,1999,2,4,Global warming and El Nino: a review of the current knowledge.,The observations of temperature from meteorological networks| as independent observations or indicators (paleoclimatic| snow cover; sea-ice and glaciers extensions| sea level)| tend towards a surface global warming| which has been more intense during the last decades. Several studies converge on the attribution of part of the most recent warming to human activities. The El Nino event (and its companion La Nina) of climate variability| induces climate anomalies which can be distributed all over the globe. The forecasting of these events| several season in advance| became foreseeable a few years ago. These forecasts| as climate change predictions| can be used as input to impact studies on the occurrence and extension of infectious diseases. It appears important that the corresponding methodologies account for the uncertainties of the climatic forecasts and predictions. (C) 1999 Elsevier| Paris. 4906,1999,2,4,Global warming and malaria expansion.,Since 1985| global warming has become a subject of concern for WHO. A meeting in Geneva in 1990 has stressed the risk of a malaria increase using mathematical models without field confirmed studies. Based on our field experience in East Africa and Madagascar| it appears that malaria increase is mainly dependent on the following factors: cancellation of vector control programs| rainfall abnormally heavy| changes of ground occupation and surface water| human exposure due to professional activities| and possibly temperature rise but in combination with other factors. On the contrary| malaria decrease was observed following the occurrence of vector control programs based on indoor house spraying using remnant effect insecticide| drought such as in Sahel| improvement of housing. Malaria is an increasing public health problem reinforced by the double resistance of parasites to anti-malarial drugs and mosquitoes to some insecticides. However| this trend could be inverted in unstable malaria regions| such as mountainous areas| by setting up appropriate vector control programs which implies a better knowledge of vector distribution and ecology. 5052,1999,2,3,Global warming and marine carbon cycle feedbacks an future atmospheric CO2,A low-order physical-biogeochemical climate model was used to project atmospheric carbon dioxide and global warming for scenarios developed by the Intergovernmental Panel on Climate Change. The North Atlantic thermohaline circulation weakens in all global warming simulations and collapses at high levels of carbon dioxide. Projected changes in the marine carbon cycle have a modest impact on atmospheric carbon dioxide. Compared with the control| atmospheric carbon dioxide increased by 4 percent at year 2100 and 20 percent at year 2500. The reduction in ocean carbon uptake can be mainly explained by sea surface warming. The projected changes of the marine biological cycle compensate the reduction in downward mixing of anthropogenic carbon| except when the North Atlantic thermohaline circulation collapses. 4899,1999,2,2,Global warming and Northern Hemisphere sea ice extent,Surface and satellite-based observations show a decrease in Northern Hemisphere sea ice extent during the past 45 years. A comparison of these trends to control and transient integrations (forced by observed greenhouse gases and tropospheric sulfate aerosols) from the Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models reveals that the observed decrease in Northern Hemisphere sea ice extent agrees with the transient simulations| and both trends are much Larger than would be expected from natural climate variations. From Long-term control runs of climate models| it was found that the probability of the observed trends resulting from natural climate variability| assuming that the models' natural variability is similar to that found in nature| is Less than 2 percent for the 1978-98 sea ice trends and Less than 0.1 percent for the 1953-98 sea ice trends. Both models used here project continued decreases in sea ice thickness and extent throughout the next century. 5028,1999,3,4,Global warming and nuclear power,The problems of pollution| global warming and renewable energy sources are not going to go away. Governments need to act with urgency if they are to produce a long-term energy policy. This paper looks at the current energy situation| and how this would project into the future without the instigation of radical changes. It concludes that nuclear is the best option available for averting a growing energy| pollution and global warming crisis. 5066,1999,2,4,Global warming and the performance of drugs used to treat parasitic and other diseases,Drug therapy for the endocrine system is implemented to replace a hormone deficiency or to prevent or reduce the formation or effects of excess hormone. Treatment of endocrine disorders covers diseases of the pituitary| adrenal| parathyroid| and thyroid glands as well as the endocrine pancreas. This article focuses on new therapies currently available for specific diseases. Administration of trilostane for treatment of hyperadrenocorticism and use of insulin glargine| protamine zinc insulin (PZI)| and porcine Lente insulin for diabetes mellitus are discussed. In addition| transdermal methimazole therapy for treatment of feline hyperthyroidism and administration of progestins for pituitary dwarfism are considered.
4938,1999,2,4,Global warming may have slowed down the deep conveyor belt of a marginal sea of the northwestern Pacific: Japan Sea,Weakening of the abyssal circulation (conveyor belt) in the Japan Sea during the 20th century is deduced from the decreasing trend of bottom dissolved oxygen (O-2). This trend indicates a shortened O-2 supply| caused by too inactive conveyor belt to compensate for biological O-2 consumption at the bottom of the sea. Recent climatic changes during the winter season in the northern Japan Sea may play a significant role in prohibiting the formation of surface seawater dense enough to sink to the bottom. It is predicted that the Japan Sea bottom water will become anoxic within a few hundred years| as it was in the last glacial maximum. 5001,1999,4,4,Global warming potential of biogenic methane,The source of carbon in biogenic methane comes from the active carbon pool. Transformation of carbon into methane| through biogenic cycling of carbon implies that the global warming (GW) contributed by biogenic methane inherits the GW of CO|. For a precise and realistic assessment of GWP of biogenic methane and its' contribution to GW| the instantaneous radiative forcing of CO| should be subtracted from the instantaneous radiative forcing of biogenic methane. The correction suggested on this account will decrease the GWP of biogenic methane by 5%. The proposed correction is significant| since 80% of the global emission of methane involve biospheric carbon belonging to the active carbon pool. 5113,1999,3,4,Global warming: discounting is not the issue| but substitutability is,The cost-benefit study of Nordhaus (1994) is representative for the neoclassical approach towards global warming. Nordhaus found that no substantial emission cuts are warranted. Most of his critics have concentrated on the issue of discounting and demanded that a lower discount rate should be applied. These criticisms first miss the point and second lead to ethically dubious| inconsistent conclusions and inefficient policy choices. They miss the point because the real problem of Nordhaus's methodology is his implicit underlying assumption of perfect substitutability between natural and other forms of capital. Given the validity of this assumption| lowering the rate of discount is inconsistent with current savings behaviour| is ethically dubious because future generations will be much richer than the current one anyway| and is inefficient because scarce financial resources are channelled into emissions abatement that exhibits rates of return far inferior to alternative public investments. Any call for aggressive emission abatement must therefore directly attack the perfect substitutability assumption of neoclassical economics. The real disagreement is about whether consumption growth can compensate for environmental degradation caused by global warming. Discounting is not the issue| but substitutability is. (C) 1999 Elsevier Science Ltd. All rights reserved. 5100,1999,2,4,Grassland vegetation changes and nocturnal global warming,Global minimum temperatures (T-MIN) are increasing faster than maximum temperatures| but the ecological consequences of this are Largely unexplored. Long-term data sets from the shortgrass steppe were used to identify correlations between T-MIN and several vegetation variables. This ecosystem is potentially sensitive to increases in T-MIN. Most notably| increased spring T-MIN was correlated with decreased net primary production by the dominant C-4 grass (Bouteloua gracilis) and with increased abundance and production by exotic and native C-3 forbs. Reductions in B. gracilis may make this system more vulnerable to invasion by exotic species and less tolerant of drought and grazing. 4957,1999,3,3,Greenhouse-gas emissions from biofuel combustion in Asia,An inventory of biofuel combustion is used to develop estimates of the emissions of carbon-containing greenhouse gases (CO2| CO| CH4| and NMHC) in Asian countries. It is estimated that biofuels contributed 573 Tg-C (teragrams of carbon; 1 Tg = 10(12) g) in 1990| about 28% of the total carbon emissions from energy use in Asia. China (259 Tg-C) and India (187 Tg-C) were the largest emitting countries. The majority of the emissions| 504 Tg-C| were in the form of CO2; however| emissions of non-CO2 greenhouse gases were significant: 57 Tg-C as CO| 6.4 Tg-C as CH4| and 5.9 Tg-C as NMHC. Because of the high rates of incomplete combustion in typical biofuel stoves and cookers and the high global warming potentials (GWP) of the products of incomplete combustion (PICs)| biofuels comprise an even larger share of energy-related emissions when measured in terms of total GWP (in CO2 equivalents): 38% over a 20-year time horizon and 31% over a 100-year time horizon. Even when the biofuel is assumed to be harvested on a completely sustainable basis tall CO2 emissions reabsorbed in the following growing season)| PIC emissions from biofuel combustion account for 4.5% of the total carbon emissions and 23% of CO2 equivalents on a short-term (20-year) GWP basis. (C) 1999 Elsevier Science Ltd. All rights reserved. 5075,1999,2,4,Hantavirus-induced acute renal failure,Recently hantavirus-infection and acute renal failure has become more important in almost all countries of Middle- and Northern Europe (nephropathia epidemica). In this part of Europe the course of the disease is commonly mild as compared to hantavirus-infection in South-East Asia and the Balkan. Recently a new subtype of hantavirus-infection with acute pulmonary syndrome has been documented in the United States| a disease with acute pulmonary distress and high mortality. Intensive investigations of nephropathia epidemica in Europe has also shown that pulmonary infiltrates are more common than noted in the past. The distribution of the virus is dependent on the rodent population (vector) and may change with global warming since rodent population may progressively increase. In Argentina a person-to-person transmission of the hantavirus subtype (Andes) was documented recently and may influence the management of the hantavirus-infected patient in the future. In summary one should always be cautious in regard to hantavirus-infection when young patients with exposure to rodents (outdoor activities) present with high fever| thrombocytopenia and severe lumbalgia. Hantavirus-serology is today available in almost all laboratories and antibody-detection is most reliable by recombinant antigen. 5070,1999,2,4,Holocene sea-level record on Funafuti and potential impact of global warming on central Pacific atolls,Geomorphic features inherited from the mid-Holocene glacio-hydro-isostatic sea-level highstand that affected the central Pacific region influence the susceptibility of atoll islets to potentially enhanced wave erosion associated with rise in sea level from global warming. Shoreline morphology on multiple islets of Funafuti atoll in central Tuvalu reflects a relative mid-Holocene sea-level highstand 2.2-2.4 m above modern sea level. Typical islets are composed of unconsolidated post-mid-Holocene sediment resting disconformably on cemented coral rubble formed beneath now-emergent mid-Holocene reef hats. Exposed remnants of the lithified islet foundations serve as resistant buttresses protecting the flanks of atoll islets from wave attack. Islets lacking cemented mid-Holocene deposits as part of their infernal structure are migratory sand cays with unstable shorelines. Any future sea-level rise greater than or equal to 0.75 m| bringing high tide above the elevation of mid-Holocene low tide| might trigger enhanced wave erosion of stable atoll islets by overtopping the indurated mid-Holocene reef platforms. As analogous threshold relations are inferred for other central Pacific atolls| the risk of future inundation of island ; nations cannot be evaluated solely in terms of expected sea-level rise with respect to gross islet elevations. (C) 1999 University of Washington. 5029,1999,3,3,Impacts of full cost pricing on the sustainability of urban transportation: towards Canada's Kyoto commitments,Certain concerns about sustainable transportation derive from the premise that significant atmospheric concentrations of carbon dioxide (CO2) and other greenhouse gases which contribute to global warming can be attributed to automotive emissions. Among measures considered to curtail automobile dependency and increase transit modal split| "full cost pricing" - a means of extracting both environmental costs and hidden subsidies which road users allegedly impose on society - has emerged as an increasingly popular suggestion. This paper examines the potential impact of full cost pricing on the "sustainability" of urban transportation| using Toronto as a case study. The analysis deals with the direct effects on mode choice and vehicle utilization resulting from increased user costs as might be achieved through fuel taxes or road pricing| as well as the indirect| longer term effects on location decisions. To investigate the land-use impacts| population distributions were altered to reflect more compact development and less urban sprawl as a proxy for relocations that might result from an increase in the costs of automobile use. Impacts are presented in terms of changes in total peak period vehicle-kilometres| mode split| and CO2 emissions. Despite several qualifications related to modelling techniques used in the case study| the analysis suggests that| overall| the impacts of large increases in road user costs appear to be less than proponents of full cost pricing would expect. In addition| the analysis suggests the fairly obvious| namely| that the greatest impacts of pricing occur within those choice markets where reasonable alternatives to the private automobile actually exist. 2264,1999,3,4,Impacts on global ozone and climate from use and emission of 2|2-dichloro-1|1|1-trifluoroethane (HCFC-123),Analyses of emissions| and consequent chlorine loading| show that projected use of 2|2-dichloro-1|1|1-trifluoroethane (HCFC-123) will result in a virtually indiscernible impact on stratospheric ozone. Parametric scenarios uphold this conclusion| even for extreme levels of emissions far exceeding those of current technologies and practices. Additional scenarios reaffirm the conclusion for continued use - beyond the scheduled phaseout date - as a refrigerant in closed systems. By contrast| use of this compound offers unique opportunities to reduce global warming. Moreover| time-dependent analyses show that the minimal contribution to stratospheric chlorine from HCFC-123 emissions will not peak until more than a decade after the residual peaks of chlorine and bromine| from prior chlorofluorocarbon and halon releases| subside. While no single index exists to compare the relative demerits of ozone depletion and climate change| three conclusions are clear. First| reversal of the buildup of bromine and chlorine (i.e.| healing of the `ozone layer') is underway and progressing on target| while sufficient practical remedies for global climate change are far more difficult. Second| the analyses show that phaseout of all chlorinated| and conceptually - but much less probably - all brominated| compounds of anthropogenic origin targets some compounds that provide environmental benefits. Most chlorinated and brominated compounds do warrant phaseout; the exceptions are those with very short atmospheric lifetimes| and consequent low ozone depletion potential (ODP)| that also offer offsetting environmental benefits. And third| since new global environmental concerns may| and probably will| be identified in the future| a more scientific approach is needed to determine environmental acceptability or rejection. 5136,1999,3,4,Including environmental aspects in production development: A case study of tomato ketchup,An environmental Life Cycle Assessment (LCA) study of a specific tomato ketchup was carried out. The objectives of the work were to illustrate how LCA can be used in production development; to investigate the influence of the geographical location of certain processes| and to find ways to improve the product's environmental performance. In the screening LCA which includes the whole life cycle| the packaging and processing sub-systems were found to be significant in the total environmental impact made by ketchup. Accordingly| six alternative systems| including packaging| processing and transportation| were modelled and simulated The environmental impact categories included were energy use| global warming| acidification| eutrophication| photo-oxidant formation and the generation of radioactive waste. It was concluded that the current geographical location of the production of ketchup is preferable; the contributions to acidification can be reduced significantly; and the environmental profile of the product can be improved for either the type of tomato paste currently used or a less concentrated tomato paste. A shift to a less concentrated paste would also mean that traditional quality parameters of the ketchup could be improved. (C) 1999 Academic Press. 5006,1999,2,3,Increased hurricane intensities with CO2-induced warming as simulated using the GFDL hurricane prediction system,The impact of CO2-induced global warming on the intensities of strong hurricanes is investigated using the GFDL regional high-resolution hurricane prediction system. The large-scale initial conditions and boundary conditions for the regional model experiments| including SSTs| are derived from control and transient CO2 increase experiments with the GFDL R30-resolution global coupled climate model. In a case study approach| 51 northwest Pacific storm cases derived from the global model under present-day climate conditions are simulated with the regional model| along with 51 storm cases for high CO2 conditions. For each case| the regional model is integrated forward for five days without ocean coupling. The high CO2 storms| with SSTs warmer by about 2.2 degrees C on average and higher environmental convective available potential energy (CAPE)| are more intense than the control storms by about 3-7 m/s (5%-11%) for surface wind speed and 7 to 24 hPa for central surface pressure. The simulated intensity increases are statistically significant according to most of the statistical tests conducted and are robust to changes in storm initialization methods. Near-storm precipitation is 28% greater in the high CO2 sample. In terms of storm tracks| the high CO2 sample is quite similar to the control. The mean radius of hurricane force winds is 2 to 3% greater for the composite high CO2 storm than for the control| and the high CO2 storms penetrate slightly higher into the upper troposphere. More idealized experiments were also performed in which an initial storm disturbance was embedded in highly simplified flow fields using time mean temperature and moisture conditions from the global climate model. These idealized experiments support the case study results and suggest that| in terms of thermodynamic influences| the results for the NW Pacific basin are qualitatively applicable to other tropical storm basins. 2257,1999,2,4,Indicators of impacts of global climate change on US water resources,Environmental and socioeconomic indicators are selected to study the impacts of global warming on the water resources of the United States. One of the indicators| regional reservoir storage vulnerability| is a particularly useful index summarizing the effectiveness of regional water supply systems to meet demands. A comparison of indicator tabulation and evaluation methods finds that reporting an indicator as a fraction of its stress threshold is most effective. Indicator display methods are compared| and the star diagram proves most effective as a visual aggregation technique. Indicators and evaluation methods are applied to the present climate and to one possible climate change scenario assuming economic growth. It is apparent that the primary impacts of global warming occur in the western U.S. and include (1) fewer relative stresses an hydroelectric systems due to an increase in energy supply from other sources| and (2) more stresses on available water resources due to increases in total withdrawals and| in some cases| decreases in flows. The writers believe that with wise indicator display methods| mathematical aggregation of indicators into indices may be unnecessary. 2305,1999,3,4,Industrial insulation: Protects the environment| improves efficiency| and saves more money than you can imagine!,Stabilizing greenhouse gas emissions to stem the impact of global climate change is becoming one of the hottest topics heading into the new century. Regardless of which side of the issue you are on| there is no debate that increasing energy efficiency is important to environmental preservation. One of the most effective energy efficient technologies available is mineral fiber insulation. The examples presented will give energy management professionals the evidence they need to consider industrial insulation a time-tested| off-the-shelf technology for achieving major reductions in operating costs and CO2 emissions. 4966,1999,2,4,Influence of landscape on the population genetic structure of the alpine butterfly Parnassius smintheus (Papilionidae),Four microsatellite DNA markers were developed which were used to examine the relationship between landscape and population genetic structure among a set of populations of the butterfly Parnassius smintheus located in the foothills of the Canadian Rockies. Detailed information on the dispersal of adult butterflies among this same set of populations was available. Simple and partial Mantel tests were used to examine the relationships between genetic distances| predicted rates of dispersal| and a number of landscape variables| all measured pairwise for 17 sample sites. Nei's standard genetic distance was negatively correlated with predicted dispersal. We observed a significant pattern of isolation by distance at a very small spatial scale. The distance between sites that was through forest was a stronger predictor of genetic distance than the distance through open meadow| indicating a significant effect of landscape on population genetic structure beyond that of simple isolation by distance. Our results suggest that rises in the tree-line in alpine areas| caused by global warming| will lead to reduced gene flow among populations of P. smintheus. 4928,1999,4,4,Infrared absorption cross section| radiative forcing| and GWP of four hydrofluoro(poly)ethers,Quantitative infrared cross-sections of the unbranched hydrofluoro(poly)ethers CHF2OCHF2| CHF2OCF2OCHF2 and CHF2OCF2CF2OCHF2 have been obtained at 298 K in the region 25-4000 cm(-1). Radiative forcing calculations have been performed for these compounds and for CHF2OCF2OCF2CF2OCHF2| and the values found per molecule are high compared to those of other CFCs and CFC replacements. Atmospheric lifetimes| calculated on the basis of experimental reaction rates with OH radicals| and global warming potentials are presented for all four compounds. (C) 1999 Elsevier Science Ltd. All rights reserved. 5081,1999,5,4,Interaction of tectonic and depositional processes that control the evolution of the Iberian Gulf of Cadiz margin,This study provides an integrated view of the growth patterns and factors that controlled the evolution of the Gulf of Cadiz continental margin based on studies of the tectonic| sedimentologic and oceanographic history of the area. Seven sedimentary regimes are identified| but there are more extensive descriptions of the late Cenozoic regimes because of the larger data base. The regimes of the Mesozoic passive margin include carbonate platforms| which become mixed calcareous-terrigenous deposits during the Late Cretaceous-early Tertiary. The Oligocene and Early Miocene terrigenous regimes developed| in contrast| over the active and transcurrent margins near the African-Iberian plate boundary. The top of the Gulf of Cadiz olistostrome| emplaced in the Late Miocene| is used as a key horizon to define the 'post-orogenic' depositional regimes. The Late Miocene progradational margin regime is characterized by a large terrigenous sediment supply to the margin and coincides with the closing of the Miocene Atlantic-Mediterranean gateways. The terrigenous drift depositional regime of the Early Pliocene resulted from the occurrence of high eustatic sea level and the characteristics of the Mediterranean outflow currents that developed after the opening of the Strait of Gibraltar. The Late Pliocene and Quaternary regimes are dominated by sequences of deposits related to cycles of high and low sea levels. Deposition of shelf-margin deltas and slope wedges correlate with regressive and low sea level regimes caused by eustasy and subsidence. During the highstand regimes of the Holocene| inner shelf prograding deltas and deep-water sediment drifts were developed under the influence of the Atlantic inflow and Mediterranean outflow currents| respectively. A modem human cultural regime began 2000 years ago with the Roman occupation of Iberia; human cultural effects on sedimentary regimes may have equalled natural factors such as climate change. Interplay of tectonic and oceanographic controls dominated the evolution of the Cadiz margin during the Cenozoic. Depositional sequences formed where the tectonic setting provided the accommodation space and the shape of the deposits has been greatly influenced by the strong unidirectional Atlantic inflow currents on the shelf and Mediterranean outflow currents on the slope. The entire cycle of the inflow and outflow deposition along the margin has been controlled first by the tectonic evolution of the Betic and Rif gateways| which become closed during the Late Miocene| and after the Messinian by the opening of the Strait of Gibraltar. Strong current development during eustatic sea level highstands of the Pliocene and Quaternary has controlled deposition because of maximum sill depths at Gibraltar for water circulation. Lowstand sea levels slowed circulation and resulted in mud drapes over the slope and regressive stratigraphic sequences over the shelf. More recently| the human industrial revolution has caused heavy metal contamination of sediment and water over the Cadiz margin. Human activity also has affected sedimentation rates because of deforestation that caused increased depositional rates near undammed rivers and decreased rates where rivers have been dammed. Future research efforts will need to focus on: (1) the effect of increased Mediterranean outflow caused by river damming plus global warming and the increased outflow as a potential trigger for new ice ages; (2) assessments of geologic hazards for planning man-made shoreline structures| developing offshore petroleum resources and maintaining undersea communications cables; and (3) confirmation of the general geologic history of the Cadiz margin. (C) 1999 Published by Elsevier Science B.V. All rights reserved. 5053,1999,2,4,Interactions between plant species and earthworm casts in a calcareous grassland under elevated CO2,We tested the hypothesis that the spatial proximity of a plant species to nutrient-rich earthworm casts (e.g.| 100% more ammonium and 30% more phosphate than in adjacent soil) is an important determinant of a plant's responsiveness to elevated atmospheric CO2. In 1995 we mapped the location of both earthworm surface casts and plants in each of 16 1.2-m(2) plots in a species-rich calcareous grassland in northwestern Switzerland. Eight plots have been maintained under current ambient CO2 concentrations (350 mu L CO2/ L)| and eight have been maintained at elevated CO2 (600 mu L CO2/L) since March 1994. in addition| total ramet production of each species| as a measure of performance| and cumulative cast production at each location (cell) were recorded at peak community biomass in 1995. Plant species within functional groups (graminoids| non-legume forbs| and legumes) differed markedly in their degree of association with casts; however| after two growing seasons elevated CO2 had no effect on plant species or functional group associations with casts. No statistically significant relationship could be demonstrated between plant-species response (i.e.| ramet production) to elevated CO2 and the degree of association with casts within any of the functional groups. However| a positive relationship was observed between the mean response of graminoid species to elevated CO2 (measured as the percentage change in mean total ramet production of graminoid species| relative to mean total ramet production at ambient CO2) and their mean degree of association (%) with surface casts at ambient CO2. Thus| graminoid species more frequently associated with casts (e.g.| Anthoxanthum odoratum and Carer caryophyllea) produced more ramets per square meter at elevated CO2 than those less frequently associated with casts (e.g.| Agrostis tenuis and Danthonia decumbens). These results| along with the strong and significant positive correlations observed between ramet production and associated cumulative cast mass across CO2 treatments for most plant species in all functional groups demonstrate: (1) that plant species differ significantly in their degree of association with nutrient-rich earthworm surface casts| regardless of the relative abundance of plant species in the community; (2) that graminoid species that are more highly associated with casts may respond more strongly to rising CO2 than those less highly associated with casts; and (3) that nutrient-rich earthworm casts stimulate the growth (ramet production) of most plant species in these grassland communities| even at current levels of atmospheric CO2. The data further suggest that these species-specific relationships between plants and casts have helped define the current structure of these highly diverse grassland communities and will likely influence their future structure as global CO2 levels continue to rise. 5047,1999,2,4,Interannual| decadal-interdecadal| and global warming signals in sea surface temperature during 1955-97,Sea surface temperature (SST) data from the NOAA analysis for the period of 1955-97 are used to identify dominant spatial and temporal patterns associated with interannual| decadal-interdecadal variabilities| and global warming. For the global annual mean SST variation| a linear trend plus pronounced decadal-interdecadal and interannual variabilities are found. The linear trend reflects a slow warming of about 0.1 degrees C in the past four decades. Superimposed on the linear trend is a relatively fast warming in the past two decades of approximately 0.2 degrees-0.3 degrees C| which is associated with the advent of the warm phase of a decadal-interdecadal oscillation. Also noted is the more frequent occurrence of warm events and the dearth of cold events on interannual timescales in the early and mid-1990s. For the last four decades| the tropical oceans have been warming at the faster rate while the extratropical North Pacific and the northwestern North Atlantic has been cooling at the slower rate. The exceptional intensity of the 1997 warm event stems from the superposition of the warm phases of a moderate interannual signal| a decadal-interdecadal oscillation| and a steady warming trend since 1955. The first annual empirical orthogonal function (EOF) mode shows an El Nino signal| modified by a warming trend. In this mode. the tropical eastern Pacific and Indian Oceans are warmed relative to the western Pacific| leading to a relaxation of the climatological east-west SST gradient. The second annual EOF mode shows that there is a secondary cooling trend in the equatorial eastern Pacific| centered near the Nino-3 (5 degrees S-5 degrees N| 150 degrees-90 degrees W;) area. This cooling is most pronounced in the boreal fall and summer. It was strongest in the 1980s| but considerably weakened in the 1990s. The cooling is well correlated with the observed surface wind divergence in the equatorial eastern Pacific cold tongue region and with anomalous surface easterly wind in the equatorial central Pacific| signaling an enhancement of the Walker circulation. The net result of the warming and cooling tendencies in the tropical eastern Pacific produces slightly less warming in the Nino-3 area compared with the equatorial central and eastern Pacific| but with little change in large-scale SST gradient across the Pacific. The implications of the present results on the mechanisms and detection of global warming are discussed. 2297,1999,4,4,Intercalibration of GMS-5 IR channels and NOAA-14 AVHRR channels 4 and 5,For the estimation of global climate change through analysis of the data from multiple satellite sensors| the intercalibration of the sensors is indispensable. In this paper| results of intercalibration of the newly developed VISSR for GMS-5 and NOAA-14 AVHRR are described. The method is based on collocated clear radiance observations with GMS-5 VISSR and NOAA-14 AVHRR. The results of the correlation analysis of the data of IR channels 1 and 2 of GMS-5 VISSR and those of channels 4 and 5 of NOAA-14 AVHRR indicate the following features. The observed brightness temperature with IR channel 1 of VISSR is about 0.8K-1.5K colder than that with channel 4 of AVHRR| while that with IR channel 2 is about 0.1K-1.0K warmer than that with channel 5 of AVHRR. The result of adjustment on working spectral response function and atmospheric correction indicates that the adjusted brightness temperatures with IR channels 1 and 2 of VISSR are about 1K colder than that with channels 4 and 5 of AVHRR. Thus this result shows IR channels 1 and 2 on GMS-5 indicate a certain disagreement with channels 4 and 5 of NOAA-14 AVHRR. (C) 1999 COSPAR. Published by Elsevier Science Ltd. 2299,1999,5,4,Intercontinental dispersal of Holarctic land mammals near the Paleocene/Eocene boundary: paleogeographic| paleoclimatic and biostratigraphic implications,The reorganization of North American and European mammalian faunas across the Paleocene/Eocene boundary is attributed to intercontinental dispersal of higher-level taxa that originated in Asia. Hypotheses positing dispersal of these higher-level taxa from a Gondwanan source (either Africa or the Indian subcontinent) are rejected on the basis of their discordance with both phylogenetic and biostratigraphic data sets. Because the only viable routes for dispersal between Holarctic continents during the late Pareocene-early Eocene were land bridges located at high latitudes| global climate change was a decisive factor mediating the nature and timing of faunal interchange. Dispersal of higher-level taxa beyond Asia was episodic and iterative| and seems to have occurred solely via Beringia. Because intercontinental dispersal of terrestrial taxa such as mammals rarely coincides precisely with their phylogenetic origin| geologically earlier first appearances of such taxa on their continent of origin are not unexpected. Given this paradigm| the Gashatan and Bumbanian Asian Land Mammal Ages (ALMAs) are likely to be older than is frequently conceived. At least some Bumbanian faunas| such as that from the Wutu Formation of Shandong Province| China| are correlated with the Clarkforkian North American Land Mammal Age (NALMA)| an interval that appears to be undocumented in the European record of mammalian evolution. 5139,1999,3,3,International cooperation and the adoption of environmentally responsible technologies,Adaption of technologies for energy production with improved environmental performance is essential for supporting world economic growth and managing the global warming and climate change issues. International cooperation is critical to ensure the environmental and energy security of world economies on a global basis. For example| the USA has acquired a great deal of useful experience in clean coal technology| which has been demonstrated with major utilities in commercial operations. The adoption and installation of clean coal technology should be given high priority worldwide. The continuous exchange of information and technology between developed and developing economies relating to current and fut4f great importance. Developed economies that possess environmentally responsive technologies and financial resources should work closely with developing economies to facilitate technology transfer and trade of technologies. Cooperation between economies can result in lowering the cast of deploying clean coal technologies directed toward the clean production of energy. This paper discusses a bilateral approach| i.e. the US/China Center for Energy and Environment| Co facilitate the mitigation of emissions and promote the clean use of coal to satisfy growing energy demand in developing economies. 5021,1999,4,4,Land-use change: effects on soil carbon| nitrogen and phosphorus pools and fluxes in three adjacent ecosystems,Changes in land use can affect soil organic matter contents and fertility and also atmospheric CO2 concentrations and global warming through soil respiration. We compared total and microbial C| N and P pools and C and N metabolism in sandy loam soils (Typic Udivitrands) under indigenous broadleaf-podocarp forest| grazed introduced pasture and 19-yr old Pinus radiata D. Don forest (planted on previous pasture) in New Zealand. Total and microbial C and N declined consistently with profile depth (except for total N in L and FH samples)| and in comparable depths of mineral soil (to 20 cm) tended to be lower in the pine than in the other systems. Total P| organic P and extractable inorganic P concentrations at comparable depths were| in contrast| lowest in the indigenous forest. Microbial P concentrations did not differ significantly between the different systems. Microbial C-to-microbial N ratios differed little among soil profile depths and ecosystems. In 0-10 cm depth mineral soil| CO2-C production| metabolic quotients (qCO(2) values) and net N mineralization were all highest in the pasture samples. Net nitrification was high in the pine and pasture samples| but much lower in the indigenous forest samples; nitrate-N was| however| consistently present in streamwater from all three ecosystems. Changes in total C and microbial C and N pools on an area basis to 20 cm depth mineral soil were greatest after conversion of the indigenous forest to pasture; total N contents were| however| as high in the pasture as in the forest and net N mineralization was highest in the pasture. On this area basis| changes in total C contents were small after conversion of pasture to pines| although the distribution within the soil profile did differ considerably between the pine and pasture systems. (C) 1999 Elsevier Science Ltd. All rights reserved. 5040,1999,5,3,Large ground surface temperature changes of the last three centuries inferred from borehole temperatures in the Southern Canadian Prairies| Saskatchewan,New temperature logs in wells located in the grassland ecozone in the Southern Canadian Prairies in Saskatchewan| where surface disturbance is considered minor| show a large curvature in the upper 100 m. The character of this curvature is consistent with ground surface temperature (GST) warming in the 20th century. Repetition of precise temperature logs in southern Saskatchewan (years 1986 and 1997) shows the conductive nature of warming of the Subsurface sediments. The magnitude of surface temperature change during that time (11 years) is high (0.3-0.4 degrees C)| To assess the conductive nature of temperature variations at the grassland surface interface| several precise air and soil temperature time series in the southern Canadian Prairies (1965-1995) were analyzed. The combined anomalies correlated at 0.85. Application of the functional space inversion (FSI) technique with the borehole temperature logs and site-specific lithology indicates a warming to date of approximately 2.5 degrees C since a minimum in the late 18th century to mid 19th century. This warming represents an approximate increase from 4 degrees C around 1850 to 6.5 degrees C today. The significance of this record is that it suggests almost half of the warming occurred prior to 1900| before dramatic build up of atmospheric green house gases. This result correlates well with the proxy record of climatic change further to the north| beyond the Arctic Circle [Overpeck| J.| Hughen| K.| Hardy| D.| Bradley| R|| Case| R.| Douglas| M|| Finney| B.| Gajewski| K.| Jacoby| G.| Jennings| A.| Lamourex| S.| Lasca| A.| MacDonald| G.| Moore| J.| Retelle| M.| Smith| S.| Wolfe| A.| Zielinski| G.| 1997. Arctic environmental change of the last four centuries| Science 278| 1251-1256.]. (C) 1999 Elsevier Science B.V. All rights reserved. 2244,1999,2,4,Latitudinal gradients in benthic community composition in Western Atlantic estuaries,Aim The community composition of benthic macroinvertebrates from 295 estuarine sires was examined in order to either confirm or challenge established boundaries of zoogeographical provinces. We also investigated the postulate that| while local distributions were determined by natural habitat characteristics such as salinity| sediment type and depth| distributions on a large geographical scale would bt: correlated with temperature. Location The Atlantic coast of the United States (on a latitudinal gradient from 42 degrees to 25 degrees N). Methods Using the descriptive techniques of cluster analysis and nonmetric multidimensional scaling| we determined the similarities in benthic community composition between sites within 1 degrees latitudinal bands and compared the biotic ordinations to natural habitat characteristics such as salinity| sediment type and depth. We then evaluated the overall community composition within each 1 degrees latitudinal band and established whether or not similarities existed between adjacent 1 degrees latitudinal bands. In this manner| we were able to confirm that a latitudinal gradient existed in estuarine benthic community composition along the western Atlantic coast. This latitudinal gradient was demarcated by biogeographical boundaries at (1) Biscayne Bay| Florida| (2) the southern end of the Indian River Lagoon| Florida| (3) St John's River| Florida| (4) Cape Island| South Carolina| (5) the mouth of the Cape Fear River| North Carolina. and (6) Caps God| Massachusetts| with 3 subprovince boundary just north of Cape May at Wildwood| New Jersey. Results The major divisions approximated widely recognized biogeographical boundaries. Average summer water temperatures correlated better than sediment type| depth| or salinity with the latitudinal groupings of sites determined by cluster analysis. Conclusions Based on this relationship| we speculate on the potential impacts of current global climate change scenarios on the distribution of benthic macroinvertebrates along the western Atlantic coast. 5059,1999,3,4,Life-cycle framework for assessment of site remediation options: Case study,An adaptation of life-cycle assessment for contaminated site remediation activities was used to examine a lead-contaminated site remediated by excavation and disposal. The study indicated emissions and impacts associated with energy consumption (transportation of contaminated soil to hazardous and nonhazardous sites)| solid waste production (contaminated soil and sludge)| land use at four sites (the contaminated site| two disposal sites| and a borrow pit for clean fill)| and potential toxicity from emissions and contaminants remaining on-site. These impacts were drawn from an inventory compiled mainly from proprietary consultants' reports| and related to impacts through several stressor-impact models; the process-related indicators of global warming potential| solid waste burden| and ecological and human toxicity potential; and site-related indicators of land use and residual human toxicity burden. Ecological and human toxicity potentials were estimated using the Mackay level III model for southern Ontario| Canada| adapted for metals. The life-cycle approach proved useful for identifying potential impacts occurring at local| regional| and global scales| over all activities and locations affected by the remediation. 2296,1999,5,4,Linked sequence development and global climate change: The Upper Mississippian record in the Appalachian basin,The character and relative stratigraphic position of paleoclimatic indicators within Upper Mississippian strata of southern West Virginia suggest a link between eustasy and patterns of continental- to global-scale atmospheric circulation. At the cyclothem scale| annual rhythms in marine facies| and paleovertisols and lacustrine carbonates in terrestrial units indicate that seasonal| semiarid climatic conditions prevailed during highstand progradation. In contrast| leached paleosols and coals that underlie sequence boundaries and occur within transgressive heterolithic facies are suggestive of humid climatic conditions during late highstand through early transgression. Milankovitch-band| glacial-interglacial cyclicity may explain both sequence development and the evidence for Late Mississippian climate fluctuations in the Appalachian: basin. Shifts from seasonal to humid climatic conditions are attributed to systematic variation in monsoonal circulation| whereby seasonal moisture became restricted to the equatorial belt during the lowstands of each similar to 400 k.y. glacial-interglacial cycle. 2226,1999,2,4,Linking observed and general circulation model upper air circulation patterns to current and future snow runoff for the Rocky Mountains,Snowmelt runoff from alpine areas is the primary source of streamflow and water supply in western North America. Increasingly| questions about the impacts of global climate change on watershed yield are being asked. This paper is a forecast of expected changes to runoff for two key rivers in western North America. The paper develops and applies linkages between historical and general circulation model (GCM) upper air circulation patterns deemed to control winter precipitation in the northern Rocky Mountain states and southern Alberta. Historical and 1 x CO2 GCM upper airflow conditions are quite similar| but there are substantive variations in the GCM 2 x CO2 upper airflows. Relative occurrence (dominance) of historical synoptic patterns is statistically linked to historical spring runoff for the Oldman and Colorado Rivers. These linkages are used to forecast variation in the future runoff on the basis of variations in synoptic pattern statistics for the 2 x CO2 GCM upper airflow patterns. 5027,1999,4,4,Living in a dusty world: Airborne dust as a key factor for alpine lakes,For a long time studies on precipitation and lake-water chemistry have focussed on the deposition of strong acids. Dust in snow and rain was analyzed much less intensively| but recent findings suggest that it may be the missing link which explains why many low-alkalinity lakes in the Alps and the Pyrenees did not become acidic and nutrient levels are seasonally high| whereas lakes in areas which are rarely influenced by dust depositions| for instance in Scandinavia| have acidified. Beside being a dominant factor for nutrient inputs to oceans| rain forests and remote lakes| dust can also play a major role in global warming and cooling| and it may significantly contribute to soil formation at mountain sites in the Mediterranean. I suggest that future changes in dust deposition and warming will be key factors for the development of alpine lakes. 2260,1999,4,3,Local estimates of global climate change: A statistical downscaling approach,For the purposes of estimating local changes in surface climate at selected stations in the central Argentina region| induced by an enhanced CO| concentration| projected by general circulation models (GCM)| a statistical method to derive local scale monthly mean minimum| maximum and mean temperatures from large-scale atmospheric predictors is presented. Empirical relationships are derived among selected variables from the NCEP re-analyses and local data for summer and winter months| tested against an independent set of observed data and subsequently applied to the MADAM and MPI GCM control runs. Finally| the statistical approach is applied to a climate change experiment performed with the MPI model to construct a local climate change scenario. The comparison between the estimated versus the observed mean temperature fields shows good agreement and the temporal evolution of the estimated variables is well-captured| though| the estimated temperatures contain less interannual variability than the observations. For the present day climate simulation| the results from the HADAM and MPI GCMs are used. It is shown that the pattern of estimated temperatures obtained using the MPI large-scale predictors matches the observations for summer months| though minimum and mean temperatures are slightly underestimated in the southeast part of the domain. However| the differences are well within the range of the observed variability. The possible anthropogenic climate change at the local scale is assessed by applying the statistical method to the results of the perturbed run conducted with the MPI model. For summer and winter months| the local temperature increase is smaller for minimum temperature than for maximum temperature for almost all the stations| yielding an enhanced temperature amplitude in both seasons. The temperature amplitude (difference between maximum and minimum) for summer months was larger than for winter months. The estimated maximum temperature increase is found to be larger for summer months than for winter months for all the stations| while for the minimum| temperature increases for summer and winter months are similar. Copyright (C) 1999 Royal Meteorological Society. 4931,1999,2,4,Long distance migration of insects to a subantarctic island,Transoceanic migration of four species of macrolepidoptera to subantarctic Macquarie Island has been detected in 7 out of 33 years Juring the period 1962-96 and is restricted to spring and autumn. Analyses of synoptic charts during the migration period show that autumn immigrants originated from New Zealand and comprised a single species of noctuid moth|Agrotis ipsilon (Walker). Spring immigrants originated from Australia and comprised two noctuids| Dasypodia selenophora Guenee and Persectania ewingii Westwood and a butterfly| Vanessa kershawi (McCoy). Autumn migrations were associated with depressions in the southern Tasman Sea. Spring migrations were associated with the eastward passage of prefrontal airflows ahead of cold fronts which extended from southern Australia to the west of Macquarie Island. In an analysis of one of these events| winds exceeded 30 ms(-1) at 300 m altitude and could have transported migrants from Tasmania to Macquarie Island overnight in less than 10 h. Flight activity was assisted by the presence of a nocturnal temperature inversion that maintained upper air temperatures above 5 degrees C. The effect of potential global warming on the migration and colonization of Macquarie Island by insects is discussed. 2262,1999,4,4,Long term changes in diurnal temperature range in Cyprus,Long term temperature data from two stations on the island of Cyprus have been analysed. Increasing trends of approximately 1 degrees C/100 years in the annual mean temperatures are found at both stations. However| the minimum daily temperatures have generally increased at a larger rate than the maximum daily temperatures| resulting in a decrease in the long-term diurnal temperature range. This decrease ranges from -0.5 degrees C/100 years to -3.5 degrees C/100 years| depending on the location. The reduction in the diurnal temperature range is consistent with observations from other parts of the globe| and may indicate that the climate in this region of the globe is part of a larger global climate change that has been occurring over the last century. It is possible that long term changes in greenhouse gas concentrations in the atmosphere are responsible for the long-term annual mean temperature increase. Furthermore| the changes in the diurnal temperature range can possibly be explained by increases in cloud cover and/or tropospheric aerosols. It is possible that part of these changes is caused by local land-use changes| primarily by the increasing urbanization of Cyprus. (C) 1999 Elsevier Science B.V. All rights reserved. 4945,1999,2,3,Long-term global warming scenarios computed with an efficient coupled climate model,We present global warming scenarios computed with an intermediate-complexity atmosphere-ocean-sea ice model which has been extensively validated for a range of past climates (e.g.| the Last Glacial Maximum). Our simulations extend to the year 3000| beyond the expected peak of CO2 concentrations. The thermohaline ocean circulation declines strongly in all our scenarios over the next 50 years due to a thermal effect. Changes in the hydrological cycle determine whether the circulation recovers or collapses in the long run. Both outcomes are possible within present uncertainty limits. In case of a collapse| a substantial long-lasting cooling over the North Atlantic and a drying of Europe is simulated. 2301,1999,2,4,Long-term increase in numbers of early-fledged Reed Warblers (Acrocephalus scirpaceus) at Lake Constance (Southern Germany),Data from a standardized mist-netting programme (the so-called "MRI-Programm") were used to assess the timing of breeding in Reed Warblers (Acrocephalus scirpaceus) at Lake Constance (South Germany). The number of Reed Warblers fledged early in the season increased significantly between 1976 and 1997 (r(s) = 0.614; p < 0.01). This is most probably due to a long-term increase in spring temperature as suggested by the high correlation between the number of early-fledged Reed Warblers and mean temperature in the first half of May (r(s) = 0.416; p < 0.01). While in the period from 1961 to 1980 the mean date of spring arrival was on the 26(th) of April| it shifted towards the 19(th) April from 1981 to 1997. However| the number of early-fledged Reed Warblers and the date of spring arrival are not significantly correlated. The lack of a significant correlation may be due to a number of reasons| for instance early arriving birds do not belong to the local population or there could be an observational bias among years. Yet| the most likely explanation is that the timing of breeding in Reed Warblers is triggered by vegetation growth and food supply rather than by the timing of spring arrival. There is growing body of evidence from this and other studies that the:recent climate change is responsible for the shift in both the timing of migration and breeding in birds. 4984,1999,2,4,Long-term reconstruction of the fire season in the mixedwood boreal forest of Western Canada,Climate modelling studies have predicted an increase in fire frequency with global warming as well as suggesting a longer fire season occurring later in the year. We used 160 years of fire scars in Pinus banksiana Lamb. dating from 1831 to 1948 and written fire records from 1927 to 1995 for Prince Albert National Park in the southern boreal forest to look for evidence of changes in the duration and timing of the fire season (defined as the months when large areas burn) that may have accompanied past changes in fire frequency. The Park's time-since-fire distribution had indicated two such changes: one around 1890 and the other around 1945| both in the direction of decreasing fire frequency. Both fire scars and written fire records indicated that the dominance of the spring fire season (April-June) has remained unchanged over the past 160 years. A small number of scars suggested that the fire season may have extended slightly into the summer (July) prior to 1890 when the fire cycle was much shorter and that the fire season may have shifted to a slightly earlier spring start after 1945 when the fire cycle was much longer.
5108,1999,2,3,Long-term responses of boreal vegetation to global change: an experimental and modelling investigation,The response of boreal ecosystems to future global change is an uncertain but potentially critical component of the feedback between the terrestrial biosphere and the atmosphere. To reduce some of the uncertainties in predicting the responses of this key ecosystem| the climate change experiment (CLIMEX) exposed an entire undisturbed catchment of boreal vegetation to CO2 enrichment (560 ppmv) and climate change (+ 5 degrees C in winter| + 3 degrees C in summer) for three years (1994-96). This paper describes the leaf metabolic responses of the vegetation to the experimental treatment and model simulations of possible future changes in the hydrological and carbon balance of the site. Randomized intervention analysis of the leaf gas exchange measurements for the dominant species indicated Pinus sylvestris had significantly (P < 0.01) higher photosynthetic rates and Betula pubescens and Vaccinium myrtillus had significantly (P < 0.01) lower stomatal conductances after three years treatment compared to the controls. These responses led to sustained increases in leaf water-use efficiency of all species of trees and ground shrubs| as determined from carbon isotope analyses. Photosynthesis (A) vs. intercellular CO2 (c(i)) response curves (A/c(i) responses)| RuBisCo analysis and leaf nitrogen data together suggested none of the species investigated exhibited down-regulation in photosynthetic capacity. At the whole ecosystem level| the improved water economy of the plants did not translate into increased catchment runoff. Modelling simulations for the site indicate this was most likely brought about by a compensatory increase in evapotranspiration. In terms of the carbon budget of the site| the ecosystem model indicates that increased CO2 and temperature would lead to boreal ecosystems of the type used in CLIMEX| and typical of much of southern Norway| acting as moderate net sinks for CO2. 5034,1999,2,4,Long-term trend toward earlier breeding in an American bird: A response to global warming?,In regions with severe winters| global warming may be expected to cause earlier onset of breeding in most animals| yet no documentation of such a trend exists in North America. In a study of marked individuals of the Mexican jay (Aphelocoma ultramarina) in southeastern Arizona| from 1971 to 1998| the mean Julian date of first clutch in the population declined significantly by 10.1 days. The date of the first nest in the population also became earlier| by 10.8 days. These changes were associated with significant trends toward increased monthly minimum temperatures on the study area| traits that are associated with the onset of breeding in this population| Significant trends from 1971 to 1997 toward warmer minimum temperatures in the months before and during the initiation of breeding were observed. These trends parallel changes in minimum temperatures and community composition in a recent study of grassland ecology in the western United States. Together| they suggest that more attention should be given to the possible ecological importance of global change in minimum temperatures. 2254,1999,2,4,Low-flow frequency exacerbation by irrigation withdrawals in the agricultural midwest under various climate change scenarios,As a possible outcome of global climate change| reductions in precipitation| while directly decreasing surface water streamflows and reserves| can also initiate or exacerbate the surface water demand by regional agriculture. Driven by the desire to maintain consistent yields and|hedge the risk of drought| farmers may implement or increase supplemental irrigation applications| obtaining water from either surface sources or aquifers. This paper presents results of an investigation of the impact of these effects on streamflows in the midwestern United States. The investigation examines the direct effect of precipitation reduction and the indirect effects of riparian and nonriparian irrigation. The crop-growth and farm-scale hydrologic model erosion-productivity impact calculator is used in conjunction with the routing features of the basin-scale hydrologic model soil water analysis tool to simulate direct and indirect effects of global change on streamflows. The analysis shows that the coupled effects of decreases in runoff and increases in irrigation may be devastating to the streams of Illinois and other midwestern states. For the example basin a 25% decrease in mean precipitation under optimal irrigation practices by both riparian and nonriparian farmers yields an increase in the annual (mean) occurrence of the historical (7)Q(10) from 3 days/year to 13 days/year| despite the streamflow accretion from groundwater-supplied irrigators. 5072,1999,3,4,Measurements of CH4 and N2O emissions from rice paddies in Fengqiu| China,Methane emissions were measured by a closed chamber method in rice plots with sandy| loamy| and clayey soil| respectively| under a water regime consisting of a flooding and draining cycle in Fengqiu| Henan Province| China in 1993 and 1994. Nitrous oxide emissions were measured for every two measurements of CH4 flux in 1994. The results showed that CH4 emissions were low compared with those recorded in previous reports and the means of CH4 fluxes ranged from 0.16 to 1.86 mg CH4 m(-2) h(-1) in the growing season (108 d). The lowest mean flux of CH4 was observed in the clayey plot in both years. Statistically| soil temperature and soil Eh at 5 cm depth significantly affected the fluctuations of the CH4 flux measured in the morning and afternoon| but they were not the main factors controlling the seasonal variation of the CH4 flux. Flooding and draining cycle| as well as high rate of water percolation and low organic matter content of the soils resulted in low emissions of CH4. In contrast| the studied plots had high emissions of N2O| ranging from - 9.02 to 1|640 mu g N m(-2) h(-1)| with arithmetic means of 168.8| 76.9| and 65.2 mu g N m(-2) h(-1) in the sandy| loamy| and clayey plots| respectively| which were comparable in magnitude to those observed in cultivated upland soils. Flooding and draining cycle| i.e.| dynamics of water status in the studied plots| was considered to be an important factor controlling N2O emission. Therefore| the mitigating effect of CH4 emission under the water regime would be offset by an increase in N2O emission. Rice fields where water management involves intermittent draining may contribute substantially to the total amount of N2O emitted to the atmosphere. 2273,1999,4,4,Measuring very low frequency sea level variations using satellite altimeter data,Very low frequency (VLF) sea. level variations are an important indicator of global climate change| and their measurement can provide important information for determining the socioeconomic impact of sea level change on coastal land use. The prospect of measuring VLF sea level variations has been assessed using approximately 5 years of satellite altimeter data from the TOPEX/POSEIDON (T/P) mission| where synoptic mapping of the geocentric height of the ocean surface is routinely achieved with a point-to-point accuracy of better than 4 fm| The global mean sea level variations measured by T/P every 10 days have an RMS of 4 mm and a rate of change + 3.1 +/- 1.3 mm/year| after accounting for an average instrument drift computed using the global tide gauge network by Mitchum (1998). A likely cause of the observed instrument drift is the microwave radiometer| which provides the water vapor delay correction| which results in a revised estimate of + 2.5 mm/year if the error is assumed to be linearly related to the mean water vapor delay. Approximately half of this rise appears related to an increase in sea level that began in mid-1996| thus it is unlikely to be sustained over the long term. Estimates of sea level change over the major ocean basins reveal that the North Atlantic has risen over the T/P mission| and this is believed to be related to decadal changes in heat storage. Maps of the geographic variability of the observed sea level trends are currently dominated by ENSO variations| and thus the climate change signals cannot currently be isolated. These results suggest that T/P| when combined with tide gauge monitoring of the satellite instruments| is achieving the necessary accuracy to distinguish sea level rise caused by climate change from the natural 'background' rate of sea level rise| although a longer time series is necessary to average out possible interannual and decadal variations. A longer time series will also reduce the errors in estimates of the altimeter calibration| providing an important constraint on any long-term instrument drift. Future research will focus on establishing a more realistic error budget for these measurements of global mean sea level| so that they can be put in the proper context with other observations of global climate change| In addition| the study of the spatial variability of the sea level rise signal will become increasingly important as a longer time series is collected. (C) 1999 Elsevier Science B.V. All rights reserved. 4997,1999,5,3,Mechanisms of climate warming at the end of the Paleocene,An abrupt episode of global warming marked the end of the Paleocene epoch. Oxygen and carbon isotope records from two widely separated sites support the notion that degassing of biogenic methane hydrate may have been an important factor in altering Earth's climate. The data show evidence for multiple injections of methane| separated by intervals in which the carbon cycle was in stasis. Correlations between the two sites suggest that even these small-scale events were global in nature. 4929,1999,3,3,Methane emissions of beef cattle grazing tall fescue pastures at three levels of endophyte infestation,Methane (CH4) is produced by fermentation in the rumen of cattle. Methane may play a part in global warming scenarios. Tall fescue (Festuca arundinacea Schreb.) is an important forage in the eastern United States. The toxic syndrome associated with the endophytic fungus Neotyphodium coenophialum (E+) can be mitigated with management strategies that improve forage quality of Ef tail fescue pastures and animal performance. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of tall fescue pasture management on CH4 production in 1997-1998. Two steers (Bos taurus) on two pastures each of E+ tall fescue| of endophyte free (E-) tall fescue| of E+/E - (1:1 ratio)| and of E+/ladino white clover (Trifolium repens L.)| and four steers and four lactating cows with nursing calves grazing either unimproved (UP) or best management practices (BMP) pastures were used to collect eructated CH4 samples. Daily CH4 emissions were about 95 to 200 g d(-1) for steers and 150 to 240 g d(-1) for cows. Steers grazing E+/clover pastures emitted 20% less CH4 kg(-1) d(-1) than steers grazing E+| E-| or E+/E- in summer. Season and animal size were the major factors affecting CH4 emissions. This first estimation of CH4 emissions from free-roaming cattle grazing tail fescue pastures indicates that (i) improved forage management strategies have little effect on daily emissions per animal that are primarily a function of rumen size and intake| and Oil the amount of emission per unit of animal product is reduced when improved practices are implemented. 4993,1999,2,4,Methanotrophic activities in tropical landfill cover soils: effects of temperature| moisture content and methane concentration,The methane oxidizing capacity of landfill cover soils was investigated through column and batch experiments by simulating conditions that are usually encountered in tropical climates. The rate of oxidation was monitored at different temperatures and moisture contents. It was observed that: a low moisture content of 6% produced negligible oxidation| whereas oxidation rates were at a maximum at moisture contents between 15 and 20%. Temperature was found to be a dominant parameter which controlled the oxidation rates. The optimum temperature was between 30 and 36 degrees C. In the column tests| the temperature influenced the methane oxidation capacity indirectly by causing the topsoil surface to become totally dry| resulting in almost zero oxidation in spite of aerobic conditions. Although some increase in oxidation rate was observed| a higher concentration of methane could not produce a corresponding increase in oxidation rates| indicating the limiting capacity of the soil to oxidize methane. A depth profile of the gas in the column system indicated that the depth of maximum oxidation was around 15 to 40 cm under normal test conditions. Experimental results indicated that the topsoil| if maintained at an optimum moisture content| could also produce a higher oxidation capacity. The results of this experimental program indicate the possibility of maximum methane oxidation in a tropical climate if the correct moisture content is maintained at the top surface. 2242,1999,3,3,Mitigation strategy to contain methane emission from rice-fields,Methane is primarily a biogenic gas| which is implicated in global climate change. Among all the sources of methane emission| paddy fields form the most dominant source. An experiment was conducted with a common paddy crop (Oryza sativa var. Vishnuparag) by amending the soils with different organic manures and biofertilizers with a view to find out an inexpensive strategy to mitigate methane emission from the rice-fields. The results revealed that there was a seasonal change in the CH(4) flux| registering a peak at heading stage in all treatments. The application of rice straw before flooding and the biofertilizer after flooding enhances CH(4) efflux from the rice-fields significantly| while composts of cowdung and leaves did not stimulate CH(4) production and| rather| decreased CH(4) fluxes. As soil pH and temperature were optimum for methanogenesis| it was likely that the organic C and the redox potential mainly modulated methane production and its emission through rice plants. 5043,1999,4,4,Mixed multiway analysis of airborne particle composition data,Airborne particle composition data were obtained from week-long samples collected at the northernmost manned site in the world| Alert| Northwest Territories| Canada| during the period from 1980 to 1991. It was found that the measured weekly average concentrations display strong persistent seasonal variations. Initially the measured concentrations of 24 constituents were arranged into both two-way and three-way data arrays| and bilinear and trilinear models were used to fit the data using positive matrix factorization (PMF). Five factors were found to explain the data quite well for both two-way and three-way modeling| and each factor represented a likely particle source. In the two-way modeling the yearly cyclical seasonal variations were not directly retrieved| since the whole 11 years of data were regarded as a single mode in the fitting. In the three-way analysis| fixed seasonality was imposed by assuming the week-to-week patterns of the source contributions to recur from year to year. The factors represent winter Arctic haze| photochemical sulfate after polar sunrise| biogenic sulfur| soil and sea salt. The resulting fit for some elements became worse because the year-to-year variation is not identical for these sources. These results suggested that a mixed two-way and three-way model might be the best representation of the data. The methodology to calculate such a mixed model has just been developed| namely the multilinear engine (ME). In this study the ME has been used to estimate a mixed two-way/three-way model for the Alert aerosol data. Five two-way and two three-way factors have been found to provide the best fit and interpretation of the data. Each factor represents a probable source with a distinctive compositional profile and seasonal variations. The five two-way factors are (i) winter Arctic haze dominated by SO42 together with metallic species and peaking from December to March| (ii) soil represented by Si| Al and Ca| (iii) sea salt| (iv) sulfate with high acidity peaking in late March/April| and (v) iodine representing most of the observed I with two maxima| one around September/October and the other around March/April. The two three-way factors are (i) bromine characterized by a maximum in the spring around March/April| and (ii) biogenic sulfur which includes sulfate and methane sulfonate (MSA) with maxima in May and August. The results obtained are consistent with those obtained in the previous study and agree with the current understanding of the Arctic aerosol. In both analyses the year-to-year strength of the biogenic factor appears to correlate strongly with the average temperature in the northern hemisphere. This result suggests that as the temperature rises| there is increased biogenic production of the reduced sulfur precursor compounds that are oxidized in the atmosphere to sulfate and MSA and could be evidence of a negative feedback mechanism in the global climate system that had been previously postulated. Copyright (C) 1999 John Wiley & Sons| Ltd. 2227,1999,2,3,Model analysis of mountain pine beetle (Coleoptera : Scolytidae) seasonality,The mountain pine beetle| Dendroctonus ponderosae Hopkins| is a natural disturbance agent of considerable consequence in western pine forests. This economically and ecologically important insect has a strong requisite for maintaining a strict seasonality. Given this ecological requirement| it is somewhat surprising that no evidence for diapause or other physiological tinting mechanism has been found. Seasonality and phenological timing for this species are apparently under direct temperature control. We investigate the consequences of direct temperature control by first constructing a computationally efficient phenology model based on previously published temperature dependent developmental data. We explored the dynamic properties of this model when subjected to observed microhabitat temperatures representing a range of thermal habitats from one region of the mountain pine beetle distribution. We also investigated the consequences of global climate change on phenology and seasonality. Our results indicate that an adaptive seasonality is a natural consequence of the interaction between developmental parameters and seasonal temperatures. Although this adaptive phenology appears to be resilient to temperature fluctuations| changes in climate within the magnitude of predicted climate change under a CO(2) doubling scenario are capable of shifting a thermally hostile environment to a thermally benign environment. Similarly| increasing temperature by the same amount resulted in phenological disruption of a previously favorable thermal habitat. We discuss the implications of these results for restricting the current distribution of mountain pine beetle| and the potential for shifting distribution caused by global climate change. 4924,1999,2,4,Modeling of sulfur sequestration in coastal marsh soils,In transgressive coastal areas| marshes form in response to sea-level rise and they generally represent an ideal environment for the sequestration of S species. Various predictions in rates of sea-level rise associated with global warming and concern for potential environmental problems from acid-sulfate weathering have prompted interest in modeling rates of S sequestration during coastal marsh pedogenesis. In this study| predictive models were derived for organic and pyrite S using data from pedons along two marsh transects in Dorchester County| MD| Organic S accumulates mainly in the organic horizons| and the rate is mainly driven by sea-level rise. Rates of organic S accumulation for the last 150 yr averaged 4.3 +/- 1.19 g m(-2) yr(-1); before this| long-term rates ranged between 0.95 and 2.05 g m(-2) yr(-1). Pyrite S sequestration reflects accumulations both in organic horizons and in the submerged mineral soil. The rate of pyrite sequestration in organic horizons is generally driven by sea-level rise and the availability of reactive Fe. During the last 150 Jr| the rates of pyrite accumulation averaged 7.2 +/- 1.6 g m(-2) yr(-1); before this| long-term rates ranged between 0.53 and 1.14 g m(-2) yr(-1). Modeled predictions of pyrite and organic S accumulations in newly forming marshes during the next century were 15 +/- 4.3 g m(-2) yr(-1) and 19 +/- 8.2 g m(-2) yr(-1)| respectively. 4921,1999,2,2,Modeling the effects of land use and climate change on riverine smallmouth bass,Anthropogenic changes in temperature and stream flow| associated with watershed land use and climate change| are critical influences on the distribution and abundance of riverine fishes. To project the effects of changing land use and climate| we modeled a smallmouth bass (Micropterus dolomieu) population in a midwestern USA| large river-floodplain ecosystem under historical (1915-1925)| present (1977-1990)| and future (2060| influenced by climate change) temperature and flow regimes. The age-structured model included parameters for temperature and river discharge during critical seasonal periods| fish population dynamics| and fishing harvest. Model relationships were developed from empirical field data collected over a 13-yr period. Sensitivity analyses indicated that discharge during the spawning/rearing period had a greater effect on adult density and fishing yield than did spawning/rearing temperature or winter discharge. Simulations for 100 years projected a 139% greater mean fish density under a historical flow regime (64.9 fish/ha) than that estimated for the present (27.1 fish/ha) with a sustainable fishing harvest under both flow regimes. Simulations under future climate-change-induced temperature and flow regimes with present land use projected a 69% decrease in mean fish density (8.5 fish/ha) from present and an unstable population that went extinct during 56% of the simulations. However| when simulated under a future climate-altered temperature and flow regime with historical land use| the population increased by 66% (45.0 fish/ha) from present and sustained a harvest. Our findings suggest that land-use changes may be a greater detriment to riverine fishes than projected climate change and that the combined effects of both factors may lead to local species extinction. However| the negative effects of increased temperature and precipitation associated with future global warming could be mitigated by river channel| floodplain| and watershed restoration. 4954,1999,4,2,Modelling future landslide activity based on general circulation models,Currently| global warming due to increasing concentrations of CO| and other greenhouse gases is widely accepted. Climate is an important forcing parameter of landslides and| hence| implications of climate change for landslide activity are of high concern for geomorphological research. The present paper offers a method for assessing climate change impacts on landslide frequency based on general circulation models (GCM). GCM results are downscaled with an empirical-statistical technique to derive local precipitation scenarios. These scenarios are used as input to a simple slope hydrological and stability model. The landslide is defined 'active' if simulated groundwater levels exceed a critical level established with the stability model. Recurrence intervals for landslide activity are obtained by applying a Gumbel regression to the simulated annual maximum groundwater levels. Furthermore| it is shown that indirect climate change impacts as well as changing non-climatic parameters can be important for future landslide frequencies too. The use of three different GCM experiments for the assessment of the activity of a small landslide in SE France did not show a consistent picture of future landslide frequencies. This is due to differences between the GCM experiments but might be enhanced by the limited ability of the applied downscaling technique to carry climate change signals. Finally| some possibilities of improving the approach are outlined and the need for better GCM experiments| which provide the basic input of the approach| is addressed. (C) 1999 Elsevier Science B.V. All rights reserved. 5012,1999,4,4,Mountain station pressure as an indicator of climate change,Surface temperature observations have been used to infer a global warming of about 0.7 degrees K over the last century. Here| we present a new way of deriving temperature trends from observations of mountain surface pressure. From the hydrostatic equation it can be shown that a warming below the mountain increases the local pressure. This signal increases with height. The derived temperature trends from a few sites are consistent with reported regional warmings and a recent acceleration. These results provide independent confirmation of regional warming of the lower troposphere on a longer time scale than is currently available from radiosondes and satellites. 4939,1999,3,2,Multi-gas assessment of the Kyoto Protocol,The Kyoto Protocol allows reductions in emissions of several 'greenhouse' gases to be credited against a CO(2)-equivalent emissions limit| calculated using 'global warming potential' indices for each gas| Using an integrated global-systems model| it is shown that a multi-gas control strategy could greatly reduce the costs of fulfilling the Kyoto Protocol compared with a CO(2)-only strategy. Extending the Kyoto Protocol to 2100 without more severe emissions reductions shows little difference between the two strategies in climate and ecosystem effects. Under a more stringent emissions policy| the use of global warming potentials as applied in the Kyoto Protocol leads to considerably more mitigation of climate change for multi-gas strategies than for the-supposedly equivalent-CO(2)-only control| thus emphasizing the limits of global warming potentials as a tool for political decisions. 5048,1999,3,4,National health| wealth| and energy use,Great disparity exists in the distribution of wealth among nations. National well-being| as measured by such commonly accepted indicators as infant mortality| child malnutrition| life expectancy| and literacy rates correlates well with national wealth| which| in turn| correlates well with energy consumption. Developed industrial nations rank high in national well-being; however| on a per-capita basis| these nations own a disproportionate share of world wealth and consume a disproportionate share of the world's energy Economic growth correlates well with growth of energy consumption in both rich and poor nations| and| conversely| reductions in energy consumption correlate with economic decline. When energy consumption is expressed as a function of gross national product (GNP) instead of on a per-capita basis| developed nations use energy more efficiently than poorer ones. Fossil fuels furnish 90% of the world's energy (oil and gas supply 63%)| and their use has grown by 14% over the last decade (oil and gas use is up 19%). Long-range concerns about depleting fossil-fuel resources and more immediate concerns about increases in atmospheric CO2 produced by their combustion and the postulated ill effects of global warming weigh against continued increase in use of fossil fuels and favor alternative energy sources. Examination of alternatives suggests that none of the alternatives| other than possibly nuclear and hydropower (both in environmental and political disfavor)| offer hope for supplying more than a fraction of demand. Hence| either the natural limits on use of fossil fuels set by depleting resources or the setting of artificial limits in an effort to control CO2 emissions (tentatively agreed to in Kyoto and Buenos Aires) contrast starkly with the need for more energy consumption to improve the economic development of all nations and particularly the poorer ones. This paper explores these relationships and identifies some of the hard choices that lie ahead that inevitably will impact the use of oil and gas.
5089,1999,5,2,Natural variability of the Earth's environments: the last two climatic extremes (18000 +/- 2000 and 8000 +/- 1000 yrs BP),The Earth's climate is tending| at a geological scale| towards a new glacial| through an alternation of cooler/warmer episodes. However| man-induced atmospheric pollution is increasing the natural greenhouse effect which| according to models| should result in a global warming of ca. 1 degrees C to 4 degrees C within a few decades. It is therefore a priority to outline the natural variability of continental environments corresponding to a few degrees difference relative to nowadays| in order to define the continental areas at risk and identify the strictly human-induced environmental changes liable to occur in the near future. Thus| maps of the world environments during the last climatic extremes (the Last Glacial Maximum| the Holocene Optimum) corresponding respectively to -4.5 degrees C and +2 degrees C relative to present global values: based upon geological multidisciplinary data| were prepared by twelve international level quaternarists at a 1:25 000 000 scale. The major differences between the two scenarios are briefly commented. ((C) Academie des sciences / Elsevier; Paris). 2239,1999,5,3,New evidence for subtropical warming during the late Paleocene thermal maximum: Stable isotopes from Deep Sea Drilling Project Site 527| Walvis Ridge,The late Paleocene thermal maximum (LPTM) was a dramatic| short-term global warming event that occurred similar to 55 Ma. Warming of high-latitude surface waters and global deep waters during the LPTM has been well documented; however| current data suggest that subtropical and tropical sea surface temperatures (SSTs) did not change during the event. Conventional paradigms of global climate change| such as CO2-induced greenhouse warming| predict greater warming in the high latitudes than in the tropics or subtropics but| nonetheless| cannot account for the stable tropical/subtropical SSTs. We measured the stable isotope values of well-preserved late Paleocene to early Eocene planktonic foraminifera from South Atlantic Deep Sea Drilling Project (DSDP) Site 527 to evaluate the subtropical response to the climatic and environmental changes of the LPTM. Planktonic foraminiferal delta(18)O values at Site 527 decrease by similar to 0.94 parts per thousand from pre-LPTM to excursion values| providing the first evidence for subtropical warming during the LPTM. We estimate that subtropical South Atlantic SSTs warmed by at least similar to 1 degrees - 4 degrees C| on the basis of possible changes in evaporation and precipitation. The new evidence for subtropical SST warming supports a greenhouse mechanism for global warming involving elevated atmospheric CO2 levels. 5102,1999,2,3,Nitrogen deposition effects on carbon dioxide and methane emissions from temperate peatland soils,Northern peatlands are important sources of carbon dioxide and methane emissions to the atmosphere. Increased atmospheric N deposition may have a significant impact on the emission of these greenhouse gases. We studied CO2 and CH4 emissions from untreated temperate pc at soils from a eutrophic and a mesotrophic Fen in a high N deposition area (the Netherlands) and from a mesotrophic fen in a low N deposition area (north-cast Poland). In addition| we investigated the effects of N| P and glucose amendments on the emissions of CO2 and CH4 from these soils. Nitrogen availability (extractable NH4+) in untreated pent from the high N area was 2.5-7.5 times higher than in the low N area| whereas the pH was 0.9-1.7 units lower. Using 6-week laboratory incubations of peat columns| we found that mean daily CO2 emission from untreated peat soils from the high N area was lower than that from the low N area. Both linear and multiple regression analysis shelved that CO2 emission was positively related to soil pH (r(2) = 0.64). Additional N supply led to pn reduction and to lower CO2 emission| especially in the low N peat soils. Thus| increased atmospheric N deposition lends| probably as a result of soil acidification| to fewer CO2 emission. Although glucose amendments resulted in increased CO2 and CH4 emission| we did not find evidence that this was caused by increased mineralization of native pest. Mean daily CH4-C emission was about 1-2 orders of magnitude lower than mean daily CO2-C emission. In the untreated peat soils from the high N eutrophic site| methane emission was higher than in the high N mesotrophic site and in the low N mesotrophic site. Linear regression analysis showed a positive relation between methane emission and soil fertility variables (r(2)=0.41-0.55)| whereas a multiple regression model revealed that methane emission was determined by N-related soil chemistry variables (r(2) = 0.93). Increased nutrient supply initially resulted in higher methane emission from soils of both mesotrophic sites| but there was no effect on the high N eutrophic soil. These results show that increased atmospheric N deposition leads to increased methane emission from low-fertility pent soils. However| the ultimate effect of atmospheric N deposition on trace gas emissions and thereby on global warming is determined by the balance between the ratios of the change in CO2-C emission and CH4-C emission and the ratio of their global warming potentials (1:21). 2265,1999,5,4,Nitrogen isotopic variations in the Gulf of California since the last deglaciation: Response to global climate change,High-resolution records of the nitrogen isotopic composition of organic matter (delta(15)N(org))| opal content| and opal accumulation rates from the central Gulf of California reveal large and abrupt variations during deglaciation and gradual Holocene changes coincident with climatic changes recorded in the North Atlantic. Homogenous sediments with relatively low delta(15)N(org) values and low opal content were deposited at the end of the last glacial period| during the Younger-Dryas event| and during the middle to late Holocene. In contrast| laminated sediments deposited in the two deglacial stages are characterized by very high delta(15)N(org) values (>14 parts per thousand) and opal accumulation rates (29-41 mg cm(-2) yr(-1)). Abrupt shifts in delta(15)N(org) were driven by widespread changes in the extent of suboxic subsurface waters supporting denitrification and were amplified in the central gulf record due to variations in upwelling| vertical mixing| and/or the latitudinal position of the Intertropical Convergence Zone. 5032,1999,3,3,Nitrogen management and the future of food: Lessons from the management of energy and carbon,The food system dominates anthropogenic disruption of the nitrogen cycle by generating excess fixed nitrogen. Excess fixed nitrogen| in various guises| augments the greenhouse effect| diminishes stratospheric ozone| promotes smog| contaminates drinking water| acidifies rain| eutrophies bays and estuaries| and stresses ecosystems. Yet| to date| regulatory efforts to limit these disruptions largely ignore the food system. There are many parallels between food and energy. Food is to nitrogen as energy is to carbon. Nitrogen fertilizer is analogous to fossil fuel. Organic agriculture and agricultural biotechnology play roles analogous to renewable energy and nuclear power in political discourse. Nutrition research resembles energy end-use analysis. Meat is the electricity of food. As the agriculture and food system evolves to contain its impacts on the nitrogen cycle| several lessons can be extracted from energy and carbon: (i) set the goal of ecosystem stabilization; (ii) search the entire production and consumption system (grain| livestock| food distribution| and diet) for opportunities to improve efficiency; (iii) implement cap and-trade systems for fixed nitrogen; (iv) expand research at the intersection of agriculture and ecology| and (v) focus on the food choices of the prosperous. There are important nitrogen-carbon links. The global increase in fixed nitrogen may be fertilizing the Earth| transferring significant amounts of carbon from the atmosphere to the biosphere| and mitigating global warming. A modern biofuels industry someday may produce biofuels from crop residues or dedicated energy crops| reducing the rate of fossil fuel use| while losses of nitrogen and other nutrients are minimized. 4916,1999,3,3,Nitrous oxide (N2O) emissions from vehicles,Assessment of the impact of vehicle emissions on the global environment requires accurate data concerning nitrous oxide| N2O| emissions. We report herein "real-world" N2O emissions from road vehicles in a tunnel In Wuppertal| Germany| together with "laboratory" emission measurements conducted at the Ford Motor Company using a chassis dynamometer with a standard driving cycle for 22 different cars and trucks. Consistent results were obtained from both approaches| suggesting that a good approximation of the average emission factor (g of N2O/g of CO2) = (6 + 2) x 10(-5). This corresponds to an emission rate of 16-8 mg of N2O/km for vehicles with fuel economies of 12-6 L/1110 km (20-40 mi/U.S. gal). N2O emissions from vehicles have a global warming impact| which is 1-3% of that of the CO2 emissions from vehicles. We estimate that the global vehicle fleet emits 0.18 +/- 0.06 Tg of N2O yr(-1) (0.11 +/- 0.04 Tg of N yr(-1))| which represents 2-6% of the atmospheric growth rate of this species| In addition to N2O| laboratory vehicle emission measurements of NH3| HONO| and HCN are reported. 5042,1999,3,4,Novel process for SiO2/Si selective etching using a novel gas source for preventing global warming,A novel gas source replacing fluorocarbon feed gases has been developed for preventing global warming. The novel gas source was designed to generate fluorocarbon species from polytetrafluoroethylene by CO2 laser ablation. The species generated from the gas source were introduced into an electron cyclotron resonance (ECR) plasma employing Ar gases. To characterize the gas source| CFx (x = 1-3) radical densities with and without plasmas were measured by infrared diode laser absorption spectroscopy. In the ECR plasma employing the novel gas source| CFx (x = 1-3) radical densities were estimated to be of the order of 10(12)-10(13) cm(-3). The gas source has been applied to the selective etching of SiO2 to Si using the ECR plasma. As a result| the etching characteristics by ECR plasma employing the novel gas source were equivalent to those by a conventional ECR plasma employing C4F8 gas. Therefore| this novel gas source is applicable to etching processes for preventing global warming. (C) 1999 American Vacuum Society. 5088,1999,2,4,Ocean spray and the thermodynamics of tropical cyclones,Serious gaps in knowledge about ocean spray at wind speeds over 40m/s remain difficult to fill by observation or experiment; yet refined study of the thermodynamics of Tropical Cyclones (including typhoons and hurricanes) requires assessment of the hypothesis that 'spray cooling' at extreme wind speeds may act to reduce (i) the initial temperature of saturated air rising in the eyewall and so also (ii) the input of mechanical energy into the airflow as a whole. Such progressive reductions at higher speeds could| for example| make any possible influence of future global warming on Tropical Cyclone intensification largely self-limiting. In order to help in extrapolation of knowledge on ocean spray to extreme wind speeds| a probabilistic analysis is introduced which allows for the effects of gusts| gravity and evaporation on droplet distributions| yet in other respects is as simple as possible. Preliminary indications from this simplified analysis appear to confirm the potential importance of spr ay cooling. 2300,1999,3,3,Offshore wind energy prospects,In last two years offshore wind energy is becoming a focal point of national and non national organizations particularly after the limitations of fossil fuel consumption| adopted by many developed countries after Kyoto conference at the end of 1997 on global climate change. North Europe is particularly interested in offshore for the limited land areas still available| due to the intensive use of its territory and its today high wind capacity. Really the total wind capacity in Europe could increase from the 1997 value of 4450 MW up to 40 000 MW within 2010| according the White Paper 1997 of the European Commission; a significant percentage (25%) could be sited offshore up to 10 000 MW| because of close saturation of the land sites at that time. World wind capacity could increase from the 1997 value of 7200 MW up to 60 000 MW within 2010 with a good percentage (20%) offshore 12 000 MW. In last seven years wind capacity is shallow waters of coastal areas has reached 34 MW. Five wind farms are functioning in the internal seas of Netherlands| Denmark| Sweden; however such siting is mostly to be considered as semi-offshore condition. Wind farms in real offshore sites| open seas with waves and water depth over 10 m| are now proposed in North Sea at 10-20 km off the coasts of Netherland| Denmark using large size wind turbine (1-2 MW). In 1997 an offshore proposal was supported in Netherland by Greenpeace after the OWEMES '97 seminar| held in Italy on offshore wind in the spring 1997. A review is presented in the paper of the European offshore wind programs with trends in technology| economics and siting effects. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. 5130,1999,4,4,On the predictability of the interannual behaviour of the Madden-Julian Oscillation and its relationship with El Nino,The Madden-Julian Oscillation (MJO) is the dominant mode of tropical variability at intraseasonal timescales. It displays substantial interannual variability in intensity which may have important implications for the predictability of the coupled system. The reasons for this interannual variability are not understood. The aim of this paper is to investigate whether the interannual behaviour of the MJO is related to tropical sea surface temperature (SST) anomalies| particularly El Nino| and hence whether it is predictable. The interannual behaviour of the MJO has been diagnosed initially in the 40-year National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis. The results suggest that prior to the mid-1970s the activity of the MJO was consistently lower than during the latter part of the record. This may be related either to inadequacies in the data coverage| particularly over the tropical Indian Ocean prior to the introduction of satellite observations| or to the real effects of a decadal time-scale warming in the tropical SSTs. The teleconnection patterns between interannual variations in MJO activity and SST show only a weak| barely significant| influence of El Nino in which the MJO is more active during the cold phase. As well as the NCEP/NCAR Reanalysis| a 4-member ensemble of 45-year integrations with the Hadley Centre climate model (HadAM2a)| forced by observed SSTs for 1949-93| has been used to investigate the relationship between MJO activity and SST. HadAM2a is known to give a reasonable simulation of the MJO| and the extended record provided by this ensemble of integrations allows a more robust investigation of the predictability of MJO activity than was possible with the 40-year NCEP/NCAR Reanalysis. The results have shown that| for the uncoupled system| with the atmosphere being driven by imposed SSTs| there is no reproducibility of the activity of the MJO from year-to-year. The interannual behaviour of the MJO is not controlled by the phase of El Nino and would appear to be mainly chaotic in character. However| the model results have confirmed the low-frequency| decadal time-scale variability of MJO activity seen in the NCEP/NCAR Reanalysis. The activity of the MJO is consistently lower in all realizations prior to the mid-1970s| suggesting that the MJO may become more active as tropical SSTs increase. This result may have implications for the effects of global warming on the coupled tropical atmosphere-ocean system. Since the observed and simulated MJOs display clear seasonality in their occurrence| the relationship with interannual changes in the mean seasonal cycle of the tropical circulation has also been investigated. In contrast to the MJO| the interannual variability in the mean seasonal cycle is reproducible and influenced by the phase of El Nino. The implications of these results for the predictability of the tropical atmosphere-ocean system are discussed| particularly with reference to the strong El Nino event of 1997 which developed in association with a period of intense MJO activity. 4911,1999,4,4,On the sensitivity of global warming experiments to the parametrisation of sub-grid scale ocean mixing,An ocean general circulation model coupled to an energy-moisture balance atmosphere model is used to investigate the sensitivity of global warming experiments to the parametrisation of sub-grid scale ocean mixing. The climate sensitivity of the coupled model using three different parametrisations of subgrid scale mixing is 3 degrees C for a doubling of CO2 (6 degrees C for a quadrupling of CO2). This suggests that the ocean has only a weak feedback on global mean surface air temperature although significant regional differences| notably at high latitudes| exist with different sub-grid scale parametrisations. In the experiment using the Gent and McWilliams parametrisation for mixing associated with mesoscale eddies| an enhancement of the surface response in the Southern Ocean is found. This enhancement is largely due to the existence of more realistic sea-ice in the climatological control integration and the subsequent enhanced ice-albedo feedback upon warming. In accordance with earlier analyses| the Gent and McWilliams scheme decreases the global efficiency of ocean heat uptake. During the transient phase of all experiments| the North Atlantic overturning initially weakened but ultimately recovered| surpassing its former strength. This suggests that in the region around the North Atlantic the ocean acts as a negative feedback on local warming during the transient phase but a positive feedback at equilibrium. During the transient phase of the experiments with a more sophisticated and realistic parametrisation of sub-grid scale mixing| warmed Atlantic water was found to penetrate at depth into the Arctic| consistent with recent observations in the region. 4909,1999,2,3,On the sensitivity of projected oceanic thermal expansion to the parameterisation of sub-grid scale ocean mixing,A coupled model of intermediate complexity is used to examine the importance of the parameterisation of sub-grid scale ocean mixing on the global mean steric sea level rise in global warming simulations. It is shown that when mixing associated with mesoscale eddies is treated in a more physically realistic way than the commonly used horizontal/vertical scheme| quasi-equilibrium projected steric sea level rise is more than two times lower in both 2 x CO2 and 4 x CO2 climates. This occurs despite the invariance of the coupled model climate sensitivity to the particular sub-grid scale mixing scheme employed. During the early phase of the transient integrations thermal expansion differences are smaller| although experiments using the Gent and McWilliams parameterisation for mixing associated with mesoscale eddies approach equilibrium more rapidly once the radiative forcing is held fixed. This reduced expansion commitment reflects a greater decoupling of the surface ocean from: the deep ocean| due to a reduction in spurious high latitude convection that occurs when a horizontal/vertical mixing scheme is used. 5046,1999,4,4,Optimal detection of global warming using temperature profiles: A methodology,Optimal fingerprinting is applied to estimate the amount of time it would take to detect warming by increased concentrations of carbon dioxide in monthly averages of temperature profiles over the Indian Ocean. A simple radiative-convective model is used to define the pattern of the warming signal| and the first 100 yr of the 1000yr control run of the Geophysical Fluid Dynamics Laboratory atmospheric-oceanic global climate model is used to estimate the natural variability of the upper-air temperatures. The signal is assumed to be the difference in two epochs of data| each epoch consisting of 12 consecutive months of monthly average temperature profiles. When the variabilities of monthly averages are assumed independent of each other| the difference in August upper-air temperatures yields the strongest fingerprint| giving a time span for a one-sigma detection of 22 yr. When correlations of natural variability between months are considered| the one-sigma detection time is 10 yr. If only an annual average profile is used| the timescale for one-sigma detection increases to 14 yr. These timescales depend on subjective judgments of the details of the model-predicted pattern of global warming. In general| using upper-air temperatures adds approximately two independent pieces of information in detecting global warming for every surface-air temperature measurement| most likely due to the expected overall pattern of tropospheric warming-stratospheric cooling. Finally| testing climate models with data must be undertaken in order to understand the uncertainties in model-predicted global warming patterns and the predictive capability of models in general. 2258,1999,4,3,Pacific northwest climate sensitivity simulated by a regional climate model driven by a GCM. Part II: 2xCO(2) simulations,Global climate change due to increasing concentrations of greenhouse gases has stimulated numerous studies and discussions about its possible impacts on water resources. Climate scenarios generated by climate models at spatial resolutions ranging from about 50 km to 400 km may not provide enough spatial specificity for use in impact assessment. In Parts I and II of this paper. the spatial specificity issue is addressed by examining what information on mesoscale and small-scale spatial features can be gained by using a regional climate model with a subgrid parameterization of orographic precipitation and land surface cover| driven by a general circulation model. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. This paper describes and contrasts the large-scale and mesoscale features of the greenhouse warming climate signals simulated by the general circulation modal and regional climate model over the Pacific Northwest. Results indicate that changes in the large-scale circulation exhibit strong seasonal variability. There is an average warming of about 2 degrees C| and precipitation generally increases over the Pacific Northwest and decreases over California. The precipitation signal over the Pacific Northwest is only statistically significant during spring| when both the change in the large-scale circulation and increase in water vapor enhance the moisture convergence toward the north Pacific coast. The combined effects of surface temperature and precipitation changes are such that snow cover is reduced by up to 50% on average| causing large changes in the seasonal runoff. This paper also describes the high spatial resolution (1.5 km) climate signals simulated by the regional climate model. Reductions in snow cover of 50%-90% are found in areas near the snow line of the control simulation. Analyses of the variations of the climate signals with surface elevation ranging from sea level to 4000 m over two mountain ranges in the Pacific Northwest show that because of changes in the alitude of the freezing level| strong elevation dependency is found in the surface temperature| rainfall. snowfall| snow cover| and runoff signals. 4974,1999,5,4,Palaeofloristic and palaeovegetational changes across the Paleocene/Eocene boundary in northern South America,A floral change occurring in northern South America at the Paleocene/Eocene boundary is analysed using palynological data. The sequence studied is an outcrop from the Venezuelan Maracaibo basin| deposited in shallow marine to coastal environments without apparent stratigraphic breaks. Significant pollen and spore counts from 237 samples were studied stratigraphically and statistically in order to compare Paleocene and Eocene palaeofloras and palaeoecological trends. The Late Paleocene/Early Eocene transition is the boundary between two floras which differ both qualitatively and quantitatively. However| the change is not sudden but stepped and gradual. Paleocene taxa seem to be of pantropical distribution| whereas Eocene assemblages are more restricted to the Neotropics. The global warming well documented elsewhere is proposed as the major cause for these changes. Trends in sporomorph diversity in this record appear to track changes in temperature documented in isotopic records from temperate regions. The extinct parent plant of Echitriporites trianguliformis is tentatively proposed to be intolerant to high temperatures| because of its absence during the Early Eocene warm phase. Palaeoecologically| although marsh and back-mangrove swamps dominated both Late Paleocene and Early Eocene assemblages| their taxonomic compositions were different| especially in the inland marsh forests. Mangrove components are scarce or absent through the whole sequence studied| suggesting the absence of these communities during the time-interval analysed. A palaeoecological subdivision into assemblage zones was not possible; instead| a recurrent pattern suggesting palynological cycles was observed. However| palynocycles could not be studied in detail due to the lack of knowledge of botanical affinities for many of the taxa involved and the apparent absence of mangrove assemblages. (C) 1999 Elsevier Science B.V. All rights reserved. 5077,1999,5,3,Palynological record of an early-mid Holocene mangrove in eastern Venezuela. Implications for sea-level rise and disturbance history,The purpose of the present report is to document the occurrence of a Holocene mangrove community on the southern Caribbean margin| and to build up a preliminary sea-level curve for Venezuela. This is accomplished through pollen analysis of a buried coastal peat layer at 9.4 m depth| as well as anatomical analysis and radiocarbon dating of an overlying wood fragment. The pollen assemblage from the peat layer is analogous to those found in present-day Caribbean mangroves. The wood comes from a 6|960+/-70 year old Rhizophora tree. This is used as evidence of a in situ mangrove community and| consequently| of the position of sea level at that time. A tentative curve for sea-level rise is presented| by compilation of radiocarbon dates on mangrove peats and corals. This study is a contribution to the evaluation of recent sea-level increase connected to the global warming| its main value being the possibility of recognizing the natural trend in sea-level rise| and separate it from the human-induced effect. 5119,1999,2,4,Past and present permafrost as an indicator of climate change,The permafrost history of the high northern latitudes over the last two million years indicates that perennially frozen ground formed and thawed repeatedly| probably in close synchronicity with the climate changes that led to the expansion and subsequent shrinkage of continental ice sheets. The early stages of the Pleistocene are the least known and the changes that occurred in the Late Pleistocene and early Holocene are the best known. Evidence that permafrost is degrading in response to the current global warming trend is difficult to ascertain. The dearest signals are probably provided by changes in permafrost distribution in the sub-Arctic regions| at the extreme southern fringes of the discontinuous permafrost zone. 5063,1999,4,4,Performance of NCAR RegCM in the simulation of June and January climates over eastern Asia and the high-resolution effect of the model,The performance of the NCAR regional climate model (RegCM) for east Asia| where topography and shoreline are rather complex| is examined through experiments to simulate the climate during 1 month using ECMWF data as lateral boundary conditions| before its application in the nested GCM/RegCM method to predict future climate changes caused by global warming. In this study| June and January climates| in which typical precipitation phenomena in Japan such as "bai-u" and winter snow are observed| are simulated using the model with lateral resolutions of 50 km (Base case) and 25 km (High case). The resolution effects of the model are also examined using a series of sensitivity studies. The main results are as follows: (1) In June and January| while cyclones passing over the inner region tend to be more intensified in the model (sometimes unrealistically) than those observed| weak cyclones in the outer region are usually not well simulated in the model. This seems to be due to the stronger control by the lateral boundary conditions| Anticyclones are stronger in the simulation than those observed| especially in the inner region| which leads to overestimation of the sea level pressure there. (2) The model yielded a lower surface air temperature than that observed| especially in January| which may depend on the performance of BATS or the radiative transfer scheme. (3) The model tends to overestimate the regional mean precipitation in the inner region and underestimate it in the outer region in June| while it was slightly underestimated in the inner and outer regions in January. Overestimations are caused by overdeveloped simulated cyclones or by the large amount of precipitation on the unrealistic topography such as a steep slope facing a moist tongue. Underestimation is due to stronger control by the lateral boundary conditions that prevent the development of cyclones or fronts. (4) In the high-resolution models| weak cyclones in the outer region and anticyclones in the inner region are more realistically simulated| although they do not greatly improve the model results in the Base case. Precipitation is increased by similar to 10-15% of that in the Base case in the inner region in June and January due to enhancement of cyclones or fronts| where the high-resolution effect of topography is only similar to 1/5 of the total high-resolution effect of the model in June. In January| for northwestern Japan| high model resolution contributes to the correction (increase) of precipitation there. Generally| the high-resolution effect of the model on the surface air temperature does not systematically improve the results but does vary locally by the improvement of model topography. To improve the model results| the lateral boundary should be moved outward (the domain of the model should be extended to the west and south) and/or the precipitation scheme should be improved| including the adjustment of parameters. BATS or the radiative transfer scheme should be improved. More recommendations for the improvement of the model are proposed. 2274,1999,2,4,Photosynthetic adjustment in field-grown ponderosa pine trees after six years of exposure to elevated CO2,Photosynthesis of tree seedlings is generally enhanced during short-term exposure to elevated atmospheric CO2| but longer-term photosynthetic responses are often more variable because they are affected by morphological| biochemical and physiological feedback mechanisms that regulate carbon assimilation to meet sink demand. To examine biochemical and morphological factors that might regulate the long-term photosynthetic response of field-grown trees to elevated CO2| we grew ponderosa pine (Pinus ponderosa Dougl. ex Laws.) trees in open-top chambers for six years in native soil at ambient CO2 (35 Pa) and elevated CO2 (70 Pa) at a site near Placerville| CA. Trees were well watered and exposed to natural light and ambient temperature. At the end of the sixth growing season at elevated CO2| net photosynthesis was enhanced 53%| despite reductions in photosynthetic capacity. The positive net photosynthetic response to elevated CO2 reflected greater relative increases in Rubisco sensitivity compared with the decreases resulting from biochemical adjustments. Analyses of net photosynthetic rate versus internal CO2 partial pressure curves indicated that reductions in photosynthetic capacity in response to elevated CO2 were the result of significant reductions in maximum photosynthetic rate (20%)| Rubisco carboxylation capacity (36%)| and electron transport capacity (21%). Decreased photosynthetic capacity was accompanied by reductions in various photosynthetic components| including total chlorophyll (24%)| Rubisco protein content (38%)| and mass-based leaf nitrogen concentration (14%). Net photosynthesis was unaffected by morphological adjustments because there was no change in leaf mass per unit area at elevated CO2. An apparent positive response of photosynthetic adjustment in the elevated CO2 treatment was the redistribution of N within the photosynthetic system to balance Rubisco carboxylation and electron transport capacities. We conclude that trees| without apparent limitations to root growth| may exhibit photosynthetic adjustment responses in the field after long-term exposure to elevated CO2. 4904,1999,4,2,Physical aspects of the greenhouse effect and global warming,According to the simplest model of the earth's radiative balance| global warming will occur with certainty as humankind increases its production and consumption of nonsolar energy. This prediction is revisited| using a broader model that allows the greenhouse effect to be considered. The new model predicts a global warming of Delta T-E =(114 K)epsilon| where epsilon is the rate of surface energy release in units of the average incident solar radiation| 342 W m(-2)| and Delta T-E is the average temperature rise at the earth's surface. Present values of these quantities| excluding geothermal sources| are epsilon = 0.69 x 10(-4) and Delta T-E = 7.9 mK. The model assigns a small number of optical parameters to the atmosphere and surface and qualifies the simple warming prediction: It is rigorous only if parameters other than epsilon are unchanged. The model is not complex and should serve as an aid to an elementary understanding of global warming. (C) 1999 American Association of Physics Teachers. 4910,1999,2,4,Physiological disturbances at critically high temperatures: A comparison between stenothermal Antarctic and eurythermal temperate eelpouts (Zoarcidae),The effect of gradually increased water temperature on the metabolism of temperate eelpout from the North Sea (Zoarces viviparus) and Antarctic eelpout (Pachycara brachycephalum) was investigated. Standard metabolic rate (SMR) was similar in cold-adapted P| brachycephalum and cold-acclimated Z| viviparus in the low temperature range. This indicates that Antarctic eelpout show no metabolic cold adaptation las originally defined by Wohlschlag); however| they do show a compensatory increase of oxygen consumption compared to warm-acclimated eelpout| SMR increased more strongly with rising temperature in P| brachycephalum than in Z| viviparus| which is reflected in a higher Arrhenius activation energy for oxygen consumption (99+/-5 kJ mol(-1)| versus 55+/-3 kJ mol(-1) for cold-acclimated Z| viviparus; means +/- S|D|)| The intracellular pH in the white musculature of Z| viviparus follows alphastat regulation over the whole investigated temperature range and dropped at a rate of -0.016 pH units per degrees C between 3 degrees C and 24 degrees C. In Antarctic eelpout white muscle pH declined at a rate of -0.015 pH units per degrees C between 0 degrees C and 3 degrees C| but deviated from alphastat at higher temperatures| indicating that thermal stress leads to acid-base disturbances in this species. The upper critical temperature limit (Tc(II); characterised by a transition to anaerobic metabolism) was found to be between 21 degrees C and 24 degrees C for Z| viviparus and around 9 degrees C for P| brachycephalum| In both species a rise of succinate concentration in the liver tissue turned out to be the most useful indicator of Tc(II)| Obviously| liver is more sensitive to heat stress than is white muscle| Accordingly| the energy status of white muscle is not diminished at Tc(II)| Heat-induced hyperglycaemia was observed in Antarctic eelpout (at 9 degrees C and 10 degrees C)| but not in common eelpout| Based on our results and on literature data| impaired respiration in combination with circulatory failure is suggested as the final cause of heat death. Our data suggest that the southern distribution limit of Zoarces viviparus is correlated with the limit of thermal tolerance. Therefore| it can be anticipated that global warming would cause a shift in the distribution of this species. 2284,1999,2,4,Phytobenthos and phytoplankton as potential indicators of climate change in mountain lakes and ponds: a HPLC-based pigment approach,Shallow mountain lakes and ponds may function as reference systems for monitoring the effects of global climate change. A survey of phytobenthos and phytoplankton communities was conducted dong an altitudinal gradient of Canadian Rocky Mountain lakes and ponds to relate patterns in algal abundance and community composition to catchment and climate-related variables. Algal abundance and community composition were quantified using pigments as analyzed by high performance liquid chromatography (HPLC). Regression analyses revealed that the abundance of rock-attached algae (epilithon) was negatively correlated (r(2) = 0.54| p < 0.001) to lake elevation and positively correlated to conductivity and dissolved organic carbon (DOC) content (r(2) = 0.52| p(cond.) < 0.03| p(DOC) < 0.01). Redundancy analysis (RDA) showed that elevation| conductivity| and DOC were also significant predictors of epilithon community composition. Epilithic diatoms (diatoxanthin diadinoxanthin| fucoxanthin) declined disproportionately with increasing water transparency and decreasing chemical concentrations. in contrast| patterns in sediment-dwelling algal (epipelon) abundance and community composition were not well-explained by the suite of measured environmental variables. Phytoplankton community composition| but not abundance| was best predicted by zooplankton biomass and elevation as cryptophytes (alloxanthin) were favored in low-elevation| montane lakes and ponds containing abundant zooplankton. Also| elevated conductivity and low DOC content were associated with a compositional shift away from planktonic cryptophytes and green algae (lutein violaxanthin) towards siliceous algae (fucoxanthin| chlorophyll c) and colonial cyanobacteria (mycoxanthophyll). These comparative results corroborate experimental findings that suggest epilithon is regulated by DOG| inorganic nutrients| and exposure to ultraviolet radiation (UV) in alpine littoral habitats. Thus| epilithon appears better suited than either phytoplankton or epipelon as a bioindicator of climatically induced variations in the abiotic environments of shallow mountain lakes and ponds. 5125,1999,2,3,Plantation forestry in Brazil: the potential impacts of climatic change,Most climatic changes predicted to occur in Brazil would reduce yields of silvicultural plantations| mainly through increased frequency and severity of droughts brought on by global warming and by reduction of water vapor sources in Amazonia caused by deforestation. Some additional negative effects could result from changes in temperature| and positive effects could result from CO(2) enrichment. The net effects would be negative| forcing the country to expand plantations onto less-productive land| requiring increased plantation area land consequent economic losses) out of proportion to the climatic change itself. These impacts would affect carbon sequestration and storage consequences of any plans for subsidizing silviculture as a global warming mitigation option. Climate change can be expected to increase the area of plantations needed to supply projected internal demand for and exports of end products from Brazil. June-July-August (dry season) precipitation reductions indicated by simulations reported by the Intergovernmental Panel on Climate Change (IPCC) correspond to rainfall declines in this critical season of approximately 34% in Amazonia| 39% in Southern Brazil and 61% in the Northeast. As an example| if rainfall in Brazilian plantation areas (most of which are now in Southern Brazil) were to decline by 50%| the area needed in 2050 would expand by an estimated 38% over the constant climate case| bringing the total plantation area to 4.5 times the 1991 area. These large areas of additional plantations imply substantial social and environmental impacts. Further addition of plantation area as a global warming response option would augment these impacts| indicating the need for caution in evaluating carbon sequestration proposals. (C) 1999 Elsevier Science Ltd. All rights reserved. 4986,1999,2,4,Possible impacts of global warming on the hydrology of the Ogallala aquifer region,The Ogallala or High Plains aquifer provides water for about 20% of the irrigated land in the United States. About 20 km(3) (16.6 million acre-feet) of water are withdrawn annually from this aquifer. In general| recharge has not compensated for withdrawals since major irrigation development began in this region in the 1940s. The mining of the Ogallala has been pictured as an analogue to climate change in that many GCMs predict a warmer and drier future for this region. In this paper we attempt to anticipate the possible impacts of climate change on the sustainability of the aquifer as a source of water for irrigation and other purposes in the region. We have applied HUMUS| the Hydrologic Unit Model of the U.S. to the Missouri and Arkansas-White-Red water resource regions that overlie the Ogallala. We have imposed three general circulation model (GISS| UKTR and BMRC) projections of future climate change on this region and simulated the changes that may be induced in water yields (runoff plus lateral flow) and ground water recharge. Each GCM was applied to HUMUS at three levels of global mean temperature (GMT) to represent increasing severity of climate change (a surrogate for time). HUMUS was also run at three levels of atmospheric CO2 concentration (hereafter denoted by [CO2]) in order to estimate the impacts of direct CO2 effects on photosynthesis and evapotranspiration. Since the UKTR and GISS GCMs project increased precipitation in the Missouri basin| water yields increase there. The BMRC GCM predicts sharply decreased precipitation and| hence| reduced water yields. Precipitation reductions are even greater in the Arkansas basin under BMRC as are the consequent water yield losses. GISS and UKTR climates lead to only moderate yield losses in the Arkansas. CO2-fertilization reverses these losses and yields increase slightly. CO2 fertilization increases recharge in the base (no climate change) case in both basins. Recharge is reduced under all three GCMs and severities of climate change. 2225,1999,2,3,Potential climate chance impacts on mountain watersheds in the Pacific Northwest,Global climate change due to the buildup of greenhouse gases in the atmosphere has serious potential impacts on water resources in the Pacific Northwest. Climate scenarios produced by general circulation models (GCMs) do not provide enough spatial specificity for studying water resources in mountain watersheds. This study uses dynamical downscaling with a regional climate model (RCM) driven by a GCM to simulate climate change scenarios. The RCM uses a subgrid parameterization of orographic precipitation and land surface cover to simulate surface climate at the spatial scale suitable for the representation of topographic effects over mountainous regions. Numerical experiments have been performed to simulate the present-day climatology and the climate conditions corresponding to a doubling of atmospheric CO2 concentration. The RCM results indicate an average warming of about 2.5 degrees C| and precipitation generally increases over the Pacific Northwest and decreases over California. These simulations were used to drive a distributed hydrology model of two snow dominated watersheds| the American River and Middle Fork Flathead| in the Pacific Northwest to obtain more detailed estimates of the sensitivity of water resources to climate change. Results show that as more precipitation falls as rain rather than snow in the warmer climate| there is a 60 percent reduction in snowpack and a significant shift in the seasonal pattern of streamflow in the American River. Much less drastic changes are found in the Middle Fork Flathead where snowpack is only reduced by 18 percent and the seasonal pattern of streamflow remains intact. This study shows that the impacts of climate change on water resources are highly region specific. Furthermore| under the specific climate change scenario| the impacts are largely driven by the warming trend rather than the precipitation trend| which is small. 2276,1999,4,3,Potential effects of gas hydrate on human welfare,For almost 30 years. serious interest has been directed toward natural gas hydrate| a crystalline solid composed of water and methane| as a potential (i) energy resource| (ii) factor in global climate change| and (iii) submarine geohazard| Although each of these issues can affect human welfare| only (iii) is considered to be of immediate importance. Assessments of gas hydrate as an energy resource have often been overly optimistic| based in part on its very high methane content and on its worldwide occurrence in continental margins. Although these attributes are attractive| geologic settings| reservoir properties| and phase-equilibria considerations diminish the energy resource potential of natural gas hydrate. The possible role of gas hydrate in global climate change has been often overstated. Although methane is a "greenhouse" gas in the atmosphere| much methane from dissociated gas hydrate may never reach the atmosphere| but rather may be converted to carbon dioxide and sequestered by the hydrosphere/biosphere before reaching the atmosphere. Thus| methane from gas hydrate may have little opportunity to affect global climate change. However| submarine geohazards (such as sediment instabilities and slope failures on local and regional scales| leading to debris flows| slumps| slides| and possible tsunamis) caused by gas-hydrate dissociation are of immediate and increasing importance as humankind moves to exploit seabed resources in ever-deepening waters of coastal oceans. The vulnerability of gas hydrate to temperature and sea level changes enhances the instability of deep-water oceanic sediments| and thus human activities and installations in this setting can be affected. 4947,1999,4,4,Potential role of solar variability as an agent for climate change,Numerical experiments have been carried out with a two-dimensional sector averaged global climate model in order to assess the potential impact of solar variability on the Earth's surface temperature from 1700 to 1992. This was done by investigating the model response to the variations in solar radiation caused by the changes in the Earth's orbital elements| as well as by the changes intrinsic to the Sun. In the absence of a full physical theory able to explain the origin of the observed total solar irradiance variations| three different total solar irradiance reconstructions have been used. A total solar irradiance change due to the photospheric effects incorporated in the Willson and Hudson (1988) parameterization| and the newly reconstructed solar total irradiance variations from the solar models of Hoyt and Schatten (1993) and Lean et al. (1995). Our results indicate that while the influence of the orbital forcing on the annual and global mean surface temperature is negligible at the century time scale| the monthly mean response to this forcing can be quite different from one month to another. The modelled global warming due to the three investigated total solar irradiance reconstructions is insufficient to reproduce the observed 20th century warming. Nevertheless| our simulated surface temperature response to the changes in the Sun's radiant energy output suggests that the Gleissberg cycle (approximate to 88 years) solar forcing should not be neglected in explaining the century-scale climate variations. Finally| spectral analysis seems to point out that the 10- to 12-year oscillations found in the recorded Northern Hemisphere temperature variations from 1700 to 1992 could be unrelated to the solar forcing. Such a result could indicate that the eleven-year period which is frequently found in climate data might be related to oscillations in the atmosphere or oceans| internal to the climate system. 5026,1999,3,3,Proper utilization of solar energy in Bangladesh: effect on the environment| food supply and the standard of living,The only really sustainable form of energy is solar energy. The densely populated tropical countries can do very well from this completely sustainable energy source without any novel technologies. Most of the commercial energy used world-wide is supplied by using nonrenewable resources. Environmental damage-global warming| ozone hole| noise| chemical and radioactive waste-is due to high energy use. Environmental deterioration is a direct consequence of wealth generated and sustained by extremely cheap fossil fuel. The price of fossil fuel does not include the cost for the deterioration of the environment. We show in this paper that even a densely populated country like Bangladesh can attain a high standard of living by a proper utilization of solar energy. We suggest that poor tropical countries should mobilize their resources to develop solar technology. (C) 1999 Elsevier Science Ltd. All rights reserved. 2288,1999,2,4,Public health consequences of global climate change in the United States - Some regions may suffer disproportionately,Current risk assessments of the likely regional health impacts of global climate change (GCC) are hindered by two factors. First| dose-response relationships between weather parameters and many of the likely health effects have not been developed| and second| reliable estimates of future regional climates across the United Slates are still beyond the scope of current modeling efforts. Consequently| probabilistic risk estimates of most of the likely regional health impacts of GCC have such a high degree of uncertainty that their usefulness to health officials dealing with regional issues is very limited. With the numerous pressures on today's health care systems| it is understandable that the possible consequences of GCC have received scant attention from regional health care decision makers. Indeed| the consensus among this community appears to be that any increases in health effects associated with GCC will be easily handled by the current health care system. However| such a position may be naive as the potential exists that an unequal distribution of such effects could overwhelm some regions| whereas others may feel little or no impact. This review of the likely regional impacts of GCC has been structured as a semianalytical look at this issue of distributional effects. Because of the lack of dose-response information and reliable estimates of future regional climates| however| it takes a historical perspective. That is| it assumes that the quality and quantity of health risks a region faces under GCC will be directly related to its recent history of health risks from warm weather/climate-related diseases as well as to the size| characteristics| and distribution of the sensitive subpopulations currently residing within its borders. The approach is semiquantitative; however| it uses national data gathered on a regional level and as such should only be used to generate a hypothesis rather than test it. When applied to the United States| its outcome leads to the hypothesis that if indeed history repeals itself| some states or regions may be more greatly affected by GCC than others| not only because historically they are more prone to summer weather/climate-related diseases| but also because they contain a greater proportion of the sensitive subpopulations in the United States. 5008,1999,3,3,PVC-plastisols - Problem solvers in the automotive industry,Ecobalance calculations confirm the competitiveness of PVC plastisols for automotive underbody coatings when ecological criteria ave considered as e.g. energy consumption or global warming potential. The consideration of risk potentials during production| processing| use and waste management reveal that PVC underbody systems and their alternatives have not shown special problems up to now. The residual components of automotive underbody coatings are safely controlled with regard to metal recycling and conversion of the light shredder residues. 2293,1999,2,4,Quantifying the impact of global climate change on potential natural vegetation,Impacts of climate change on vegetation are often summarized in biome maps| representing the potential natural vegetation class for each cell of a grid under current and changed climate. The amount of change between two biome maps is usually measured by the fraction of cells that change class| or by the kappa statistic. Neither measure takes account of varying structural and Aoristic dissimilarity among biomes. An attribute-based measure of dissimilarity (Delta V) between vegetation classes is therefore introduced. Delta V is based on (a) the relative importance of different plant life forms (e.g| tree| grass) in each class| and (b) a series of attributes (e.g. evergreen-deciduous| tropical-nontropical) of each life form with a weight for each attribute. Delta V is implemented here for the most used biome model| BIOME 1 (Prentice| I. C. et al.| 1992). Multidimensional scaling of pairwise Delta V values verifies that the suggested importance values and attribute weights lead to a reasonable pattern of dissimilarities among biomes. Dissimilarity between two maps (Delta V) is obtained by area-weighted averaging of Delta V over the model grid. Using Delta V| present global biome distribution from climatology is compared with anomaly-based scenarios for a doubling of atmospheric CO2 concentration (2 x CO2)| and for extreme glacial and interglacial conditions. All scenarios are obtained from equilibrium simulations with an atmospheric general circulation model coupled to a mixed-layer ocean model. The 2 x CO2 simulations are the widely used OSU and GFDL runs from the 1980's| representing models with low and high climate sensitivity| respectively. The palaeoclimate simulations were made with CCM1| with sensitivity similar to GFDL. Delta V values for the comparisons of 2 x CO2 with present climate are similar to values for the comparisons of the last interglacial and mid-Holocene with present climate. However| the two simulated 2 x CO2 cases are much more like each other than they are to the simulated interglacial cases. The largest Delta V values were between the last glacial maximum and all other cases| including the present. These examples illustrate the potential of Delta V in comparing the impacts of different climate change scenarios| and the possibility of calibrating climate change impacts against a palaeoclimatic benchmark. 4972,1999,2,4,Recent abatement of easterly winds in the northern Adriatic,Easterly winds from the northern Adriatic contribute| together with atmospheric depressions| and the often decisive southerly winds from the southern and middle Adriatic| to produce damaging sea surges in the Gulf of Venice. A new statistical analysis of 3-hourly wind records from Trieste for the period 1951-1996| has shown a clear decline in the frequency and strength of Bora and other easterlies. This abatement is not accompanied by a strengthening of winds from other directions| but by more frequent calm situations (from 26% of total observations in the 19509| to 44% during the last 10 years| and even to over 60% during the early 1980s). Similar (although weaker) declining trends for the easterlies have been recorded at other stations in the northern Adriatic (Ronchi| Venice). An inspection of previously published data from Trieste suggests that such trends may have been going on| possibly with minor fluctuations| since at least the beginning of regular instrumental records| in the late 18608. Such changes in wind pattern| which have favourable effects on the frequency of coastal flooding| may be due| at least in part| to interdecadal climate variability. However| the persistence of certain trends suggests a climatic shift| with| in particular| less-frequent situations| with strong atmospheric pressure gradients between highs in central/eastern Europe and lows in southern Italy or in the Adriatic area. Such situations may be a consequence of recent global warming and of less-frequent drifts of polar cold air towards middle latitudes. Copyright (C) 1999 Royal Meteorological Society. 5030,1999,3,4,Refrigeration with electrolytic and immiscible liquid-liquid systems,Due to environmental concerns| new refrigerants are urgently needed to meet the refrigeration needs in the coming century. Two novel absorption refrigeration systems are considered herewith (1) the mixed-solvent electrolytes| and (2) mixtures exhibiting liquid-liquid immiscible phase separations as working fluids. When properly designed| they can avoid the global warming and ozone depletion pitfalls usually associated with the chlorofluorcarbon refrigerants. Electrolytic systems such as water-lithium bromide-ethylene glycol| and ammonia-sodium thiocyanate mixtures can serve as cooling media in an absorption refrigeration cycle with salts as absorbents and water (or ammonia) as refrigerants. The cycle efficiency (expressed in terms of the coefficient of performance-COP) plays a major role in determining their economical viability. Tn this paper| we study the desirable molecular characteristics that the salt systems should possess in order to yield high COP. We set out to answer the questions: how do we select and screen electrolytic mixtures as working fluids? and what molecular properties impact on design and efficiency? We shall apply an accurate theory| namely| the mean-spherical approach (MSA) to electrolytes to model the activities of the salt solutions. The results are checked with available data to ascertain its accuracy. Predictions can then be made on the performance of electrolytic working fluids in applications such as air-conditioning and refrigeration. Next| for mixtures of chemical solvents that form liquid-liquid immiscibility gaps| a Maxwell cycle can be constructed to generate refrigeration. In order for this class of solvents to work| a number of practical and thermodynamic considerations must be satisfied. We examine several functional criteria that are needed to operate the cycle: the first is concerned with the free energy-of-mixing behavior; the second| the pattern of the immiscibility gaps; and the last| most importantly| the influence of activity coefficients on absorption. This type of refrigeration| not yet commercially developed| promises to be highly economical due to hardware savings (elimination of the condenser)| and energy savings (no need to supply the latent heats of evaporation). (C) 1999 Elsevier Science B.V. All rights reserved. 2259,1999,2,4,Regional cloud cover change associated with global climate change: Case studies for three regions of the United States,Land-based observations of cloud cover. for the period 1900-87 and averaged over three geographical regions of the United States (coastal southwest| coastal northeast| and southern plains). show strong positive correlations with one estimate of global mean surface temperature| a finding consistent with prior investigations that suggest cloud cover over land has increased during global warm periods relative to cold periods. it is also found that the strengths of three permanent high/low pressure systems (North Pacific high| Icelandic low| anti Azores high) are negatively correlated with global mean surface temperature| suggesting a possible connection between regional cloud cover| for certain locations| and the strengths of adjacent high/low pressure systems. Specifically| for the regions considered it is suggested that the coastal southwest cloud cover is related to changes in the strength of the subtropical North Pacific high| that For the southern plains also to the strength of the North Pacific high| and that for the coastal northeast to the strength of the Icelandic low. Thus the climate-induced change in cloud cover for certain regions appears related| at least in part| to climate-induced change in the strengths of adjacent high/low pressure systems| and plausible physical explanations for this relation are provided for the three regions that have been studied. This does not| of course| provide a direct physical cause-and-effect explanation for the changes in regional cloud cover| because the mechanisms that cause the intensities of the high/low pressure systems to change are not understood. 5013,1999,4,4,Relationship between soils and Amazon forest biomass: A landscape-scale study,Above-ground dry biomass of living trees including palms was estimated in 65 l ha plots spanning a 1000 km(2) landscape in central Amazonia. The study area was located on heavily weathered| nutrient-poor soils that are widespread in the Amazon region. Biomass values were derived by measuring the diameter-at-breast-height (DBH) of all greater than or equal to 10 cm trees in each plot| then using an allometric equation and correction factor for small trees to estimate total tree biomass. Detailed information on soil texture| organic carbon| available water capacity| pH| macro- and micro-nutrients| and trace elements was collected from soil surface samples (0-20 cm) in each plot| while slope was measured with a clinometer. Biomass estimates varied more than two-fold| from 231 to 492 metric tons ha(-1)| with a mean of 356 +/- 47 tons ha(-1). Simple correlations with stringent (p < 0.006) Bonferroni corrections suggested that biomass was positively associated with total N| total exchangeable bases| K+| Mg2+| clay| and organic C in soils| and negatively associated with Zn+| aluminum saturation| and sand. An ordination analysis revealed one major and several minor soil gradients in the study area| with the main gradient discriminating sites with varying proportions of clay (with clayey soils having higher concentrations of total N| organic C| most cations| and lower aluminum saturation and less sand). A multiple regression analysis revealed that the major clay-nutrient gradient was the only significant predictor| with the model explaining 32.3% of the total variation in biomass. Results of the analysis suggest that soil-fertility parameters can account for a third or more of the variation in above-ground biomass in Amazonian terra-firme forests. We suggest that| because the conversion of forest to pasture tends to reduce the nitrogen| clay| organic carbon| and nutrient contents of soils| forests that regenerate on formerly cleared lands may have lower biomass than the original forest| especially in areas with low soil fertility. (C) 1999 Elsevier Science B.V. All rights reserved. 5055,1999,2,4,Remarkable waxing| waning| and wandering of populations of Mimulus guttatus: An unexpected example of global warming,The purpose of this study was to observe the dynamics of a meta-population of Mimulus guttatus. Changes in size and location of 16 original populations and the new populations established in their vicinities in Big Cottonwood Canyon| Salt Lake County| Utah| were observed for 25 yr. Twenty-three new populations appeared. Seven original populations and 13 new populations had become extinct by the end of the observation period in 1996. Many populations died out and were reestablished| often repeatedly| during the observation period. Altogether there were 54 population disappearances and 34 reappearances. Many populations changed size as much as 100-fold or more from year to year. There were spectacular examples of populations expanding to fill newly available| large habitats. Frequent extinctions were due overwhelmingly to the canyon drying trend| which led to the drying up of most Mill D North drainage springs| creeks| and ponds. Precipitation and minimum temperatures increased moderately during the observation period. The growing season lengthened almost 50%| a typical consequence of global warming. The drying trend| lengthened growing season; and disappearance of Mimulus populations in Big Cottonwood Canyon appear to be a clear| local example of global warming. 5076,1999,3,3,Remote microwave plasma source for cleaning chemical vapor deposition chambers: Technology for reducing global warming gas emissions,The semiconductor industry uses a large amount of perfluoro compounds (PFCs)| and their impact on global warming has become a major environmental concern. In the semiconductor industry| PFC are used to periodically remove deposits from the chamber walls of chemical vapor deposition (CVD) reactors after film deposition. These chamber clean processes account for typically 50%-70% of the PFC usage in a semiconductor wafer fabrication site| the rest being mainly used for wafer-etching processes. With a conventional parallel plate radio frequency (rf) plasma reactor| the PFC gas utilization is incomplete and a large fraction of unreacted gas can be emitted in the atmosphere. This paper describes a microwave plasma source that provides as high as 99.9% utilization removal efficiency (URE) of the reactant gas (NF3) during chamber clean. This technology brings the million metric tons carbon equivalent (MMTCE) of a chamber clean to negligible levels and also enhances the chamber clean efficiency and the system throughput. Here we review the requirements for the manufacturability of a remote plasma clean process. Gaseous Fourier transform infrared and quadrupole mass spectroscopy techniques have been used to characterize the clean process| the by-products of the reaction| and the efficiency in reducing the MMTCE of CVD chamber cleans. (C) 1999 American Vacuum Society. [S0734-211X(99)06802-X]. 4967,1999,3,3,Renewable energy - the way forward,This paper outlines the growing need of energy in the developing countries and the acute population growth| which will exceed 10 billion by the year 2050. It describes the achievement and progress made in geothermal| hydro-power| biomass conversion| solar thermal technology| wind energy conversion and the ever increasing usage of photovoltaics. The paper also addresses the barriers and problems which face renewable energy users and producers. It is evident now that global warming is setting in and is going to change the climate as well as the terrain of many countries unless drastic measures are taken. The recent Kyoto meeting emphasised the importance of limiting CO2 emissions and to abide by some form of agreement to reduce emissions. Countries such as India| China and Indonesia| which represent nearly half the world's population| are actively involved in using renewable energy as the only means of sustaining their energy growth. It concludes that renewable energy penetration into the energy market is much faster than was expected a few years ago and by the year 2020| 10-15% of our prime energy will be met by renewable energy. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. 5011,1999,5,4,Response of plant-insect associations to Paleocene-Eocene warming,The diversity of modern herbivorous insects and their pressure on plant hosts generally increase with decreasing Latitude. These observations imply that the diversity and intensity of herbivory should increase with rising temperatures at constant Latitude. Insect damage on fossil Leaves found in southwestern Wyoming| from the Late Paleocene-early Eocene global warming interval| demonstrates this prediction. Early Eocene plants had more types of insect damage per host species and higher attack frequencies than Late Paleocene plants. Herbivory was most elevated on the most abundant group| the birch family (Betulaceae). Change in the composition of the herbivore fauna during the Paleocene-Eocene interval is also indicated. 5090,1999,2,3,Response to CO2 transient increase in the GISS coupled model: Regional coolings in a warming climate,The GISS coupled atmosphere-ocean model is used to investigate the effect of increased atmospheric CO2 by comparing a compounded 1% CO2 increase experiment with a control simulation. After 70 yr of integration| the global surface air temperature in the 1% CO2 experiment is 1.43 degrees C warmer. In spite of this global warming| there are two distinct regions| the northern Atlantic Ocean and the southern Pacific Ocean| where the surface air temperature is up to 4 degrees C cooler. This situation is maintained by two positive feedbacks: a local effect on convection in the South Pacific and a nonlocal impact on the meridional circulation in the North Atlantic. The poleward transport of latent energy and dry static energy by the atmosphere is greater in the 1% CO2 experiment| caused by warming and therefore increased water vapor and greater greenhouse capacity at lower latitudes. The larger atmospheric transports tend to reduce upward vertical fluxes of heat and moisture from the ocean surface at high latitudes| which has the effect of stabilizing the ocean| reducing both convection and the thermohaline circulation. With less convection| less warm water is brought up from below| and with a reduced North Atlantic thermohaline circulation (by 30% at time of CO2 doubling)| the poleward energy transport by the oceans decreases. The colder water then leads to further reductions in evaporation| decreases of salinity at high latitudes| continued stabilization of the ocean| and maintenance of reduced convection and meridional overturning. Although sea ice decreases globally| it increases in the cooling regions| which reduces the overall climate sensitivity| especially in the Southern Hemisphere. Tropical warming has been observed over the past several decades; if modeling studies such as this and others that have produced similar effects are valid| these processes may already be beginning. 2269,1999,2,4,Responses of soil microarthropods to changes in soil water availability in tallgrass prairie,Changes in precipitation and soil water availability predicted to accompany global climate change would impact grasslands| where many ecosystem processes are influenced by water availability. Soil biota| including microarthropods| also are affected by soil water content| although little is known about how climate change might affect their abundance and distribution. The goal of this study was to examine soil microarthropod responses to altered soil water availability in tallgrass prairie ecosystems. Two separate experiments were done. The first utilized control and irrigated plots along a topographic gradient to examine the effects of soil water content on microarthropod densities. Microarthropods| mainly Acari| were significantly less abundant in irrigated plots and were generally less abundant at the wetter lowland sites. The second study utilized reciprocal core transplants across an east-west regional precipitation gradient. Large| intact cores were transplanted between a more mesic tallgrass site (Konza Prairie) and a more arid mixed-grass site (Hays) to determine the effects of different soil water regimes on microarthropod abundance and vertical distribution. Data from non-transplanted cores indicated greater total microarthropod densities at the drier Hays site| relative to the wetter Konza Prairie site. Data from the transplanted cores indicated significant effects of location on Acari densities in cores originating from Hays| with higher densities in cores remaining at Hays| relative to those transplanted to Konza. Acari densities in cores originating from Konza were not affected by location; however| oribatid mite densities generally were greater in cores remaining at Konza Prairie. These results confirm the importance of soil water content in affecting microarthropod densities and distributions in grasslands| and suggest complex| non-linear responses to changes in water availability. 4922,1999,2,4,Responses of tundra plants to experimental warming: Meta-analysis of the international tundra experiment,The International Tundra Experiment (ITEX) is a collaborative| multisite experiment using a common temperature manipulation to examine variability in species response across climatic and geographic gradients of tundra ecosystems. ITEX was designed specifically to examine variability in arctic and alpine species response to increased temperature. We compiled from one to four years of experimental data from 13 different ITEX sites and used meta-analysis to analyze responses of plant phenology| growth| and reproduction to experimental warming. Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however| there was little impact on growth cessation at the end of the season. Quantitative measures of vegetative growth were greatest in warmed plots in the early years of the experiment| whereas reproductive effort and success increased in later years. A shift away from vegetative growth and toward reproductive effort and success in the fourth treatment year suggests a shift from the initial response to a secondary response. The change in vegetative response may be due to depletion of stored plant reserves| whereas the lag in reproductive response may be due to the formation of flower buds one to several seasons prior to flowering. Both vegetative and reproductive responses varied among life-forms; herbaceous forms had stronger and more consistent vegetative growth responses than did woody forms. The greater responsiveness of the herbaceous forms may be attributed to their more flexible morphology and to their relatively greater proportion of stored plant reserves. Finally| warmer| low arctic sites produced the strongest growth responses| but colder sites produced a greater reproductive response. Greater resource investment in vegetative growth may be a conservative strategy in the Low Arctic| where there is more competition for light| nutrients| or water| and there may be little opportunity for successful germination or seedling development. In contrast| in the High Arctic| heavy investment in producing seed under a higher temperature scenario may provide an opportunity for species to colonize patches of unvegetated ground. The observed differential response to warming suggests that the primary forces driving the response vary across climatic zones| functional groups| and through time. 2283,1999,2,4,Root hydraulic conductivity of Larrea tridentata and Helianthus annuus under elevated CO2,While investigations into shoot responses to elevated atmospheric CO2 are extensive| few studies have focused on how an elevated atmospheric CO2 environment might impact root functions such as water uptake and transport. Knowledge of functional root responses may be particularly important in ecosystems where water is limiting if predictions about global climate change are true. In this study we investigated the effect of elevated CO2 on the root hydraulic conductivity (L-p) of a C-3 perennial| Lawea tridentata| and a C-3 annual| Helianthus annuus. The plants were grown in a glasshouse under ambient (360 mu mol mol(-1)) and elevated (700 mu mol mol(-1)) CO2. The L-p through intact root systems was measured using a hydrostatic pressure-induced flow system. Leaf gas exchange was also determined for both species and leaf water potential (psi(leaf)) was determined in L| tridentata| The L-p of L| tridentata roots was unchanged by an elevated CO2 growth environment. Stomatal conductance (g(s)) and transpiration (E) decreased and photosynthetic rate (A(net)) and psi(leaf) increased in L| tridentata| There were no changes in biomass| leaf area| stem diameter or root : shoot (R : S) ratio for L| tridentata. In H| annuus| elevated CO2 induced a nearly two-fold decrease in root L-p. There was no effect of growth under elevated CO2 on A(net)| g(s)| E| above- and below-ground dry mass| R : S ratio| leaf area| root length or stem diameter in this species. The results demonstrate that rising atmospheric CO2 can impact water uptake and transport in roots in a species-specific manner. Possible mechanisms for the observed decrease in root L-p in H| annuus under elevated CO2 are currently under investigation and may relate to either axial or radial components of root L-p. 4981,1999,2,4,Runoff generation and water table fluctuations in blanket peat: evidence from UK data spanning the dry summer of 1995,Understanding of the hydrology of upland blanket peatlands has been limited both by the logistical difficulties of obtaining data from such environments and by technical difficulties with plot scale investigations of peat hydrology. The relative importance of infiltration-excess and percolation-excess as runoff generating mechanisms as opposed to the saturation-excess mechanism remains unclear. This study uses catchment-scale runoff data| in combination with monitoring of water table levels| to identify the relative importance of these mechanisms for an upland peat catchment within the Moor House National Nature Reserve in the UK. Mean runoff coefficients for the catchment are 0.4 and the hood hydrographs are flashy. Monitored water table in the catchment is within 5 cm of the surface (i.e. within the acrotelm) 93% of the time. High stream flows always occur at times of high water table suggesting that overland and near surface runoff is controlled by saturation of the catotelm rather than by infiltration capacity. Depressed rates of water table recovery at the end of a prolonged period of low water table in 1995 suggest possible physical changes once the peat has dried out. The likelihood that such periods of low water table will become more common under global warming scenarios raises concern over the impact of such changes: increased erosion| water discoloration and increased CO2 flux may result. (C) 1999 Elsevier Science B.V. All rights reserved. 4965,1999,2,4,Sea-level rise and coastal forest retreat on the west coast of Florida| USA,We investigated patterns| rates| and mechanisms of forest replacement by salt marsh in relation to sea-level rise on the west coast of Florida| USA. The geomorphology of this region typifies that of low-lying| limestone coastlines considered highly susceptible to sea-level rise (e.g.| much of the eastern Gulf of Mexico| the Yucatan Peninsula| and low-lying limestone islands throughout the world). This coast is microtidal| shallowly sloping| and has a rate of relative sea-level rise similar to that of eustatic rise. To determine patterns of forest change in relation to sea-level rise| we examined patterns of tree-species zonation| tree recruitment| and tree mortality in relation to site elevation and tidal-flooding frequency. To reconstruct histories of forest change in relation to sea-level rise| we estimated age distributions of Sabal palmetto| the most widely distributed tree species at our site| relating age structures of stands to reconstructed histories of tidal flooding in the stands. Finally| to assess the relative roles of flooding stress (hypoxia)| salt exposure| and competition from encroaching salt-marsh vegetation in the decline of forest stands| we examined patterns of soil redox potential| groundwater salinity| and density of halophytic vegetation among stands in different stages of decline. Zonation among tree species was related to tidal-flooding frequency. For most trees| seedlings were absent from the most frequently flooded stands in which the species occurred. Reconstructed flooding histories of stands and age estimates for S. palmetto suggest that many decades elapse between cessation of regeneration and local elimination of a tree species. Even during the relatively short duration of the study (4 yr)| however| composition of some stands changed in the direction predicted from species zonation and sea-level rise. Forest understory replacement by halophytic vegetation appeared to follow| rather than cause| failure of tree regeneration. Tidal flooding rarely produced severe reducing conditions in soil| but groundwater salinity was correlated with tidal-flooding frequency. Forest retreat in this system| therefore| involves the development of relict (non-regenerating) stands of different tree species at different flooding frequencies. Exposure to salt appears to be the major cause of tree regeneration failure| with flooding stress and interference from marsh playing minor or negligible roles. These interactions differ somewhat from those on deltaic coasts or coasts with high freshwater outflows| where flooding stress may play a larger role in regeneration failure| and from sandy coasts| where erosion may play a larger role in forest retreat. Regardless of the cause of tree regeneration failure| the development of relict stands may be a general forest response to sea-level rise. 2306,1999,2,4,Seasonal variation in carbon accumulation by a high latitude forest ecosystem,This study is concerned with interactions between a boreal forest ecosystem and the atmosphere| measured in an old-growth muskeg ecosystem (predominantly black spruce Picea mariana) in the BOREAS Southern study area (SSA)| Saskatchewan| Canada| during 1996. We focus on efforts to understand the net ecosystem exchange of CO2 in terms of the sub-component fluxes operating within the ecosystem. The component fluxes of primary interest are photosynthesis| respiration and evapotranspiration of foliage| and the efflux of CO2 from the forest floor. Woody biomass respiration is also considered. Methodologies were developed to study these fluxes on a continuous basis. An "open" system gas exchange chamber for measuring soil CO2 efflux was designed that eliminated the major problems that have been associated with this methodology in the past. The system was used to investigate temporal and spatial variation in soil CO2 efflux at the field site. A scheme that integrated this temporal and spatial variation was used to estimate the CO2 efflux from the forest floor for an entire year. Seasonally| soil CO2 efflux varied between low| but positive| rates before the springtime thaw and after the winter freeze| to rates as high as 14 mu mol m(-2) s(-1) in late summer. The total carbon efflux from the soil during the measurement period varied from point to point between 152 and 1310 g (C) m(-2) yr(-1)| the total soil carbon efflux for the whole ecosystem over the measurement period was estimated to be 790 g (C) m(-2) yr(-1). A "branch bag" methodology for studying the gas exchange of whole tree branches was developed and operated for an entire growing season. Daily maximum photosynthetic rates were zero at the beginning and end of the year and reached a maximum of approximate to 6 mu mol m(-2) s(-1). Night-time respiration reached a maximum rate of approximate to 0.8 mu mol g(-1) s(-1). Total daytime carbon uptake during the measurement period ranged from 12.6 to 22.6 mol m(-2) (leaf area) yr(-1) for individual branches and total night-time loss ranged from 1.98 to 2.27 mol kg(-1) (dry weight) yr(-1). Total net photosynthesis for the canopy during the measurement period was estimated to be 919 g (C) m(-2) (ground area) yr(-1). Above-ground autotrophic respiration in woody tissue during the measurement period was estimated to be 89 g (C) m(-2) y(-1). In 1996| the estimated net carbon uptake during the measurement period for the ecosystem was 222 g (C) m(-2) yr(-1). This was the small difference between a large photosynthetic influx and a large respiratory efflux. The carbon source/sink strength of this ecosystem is thus very sensitive to changes in environmental conditions| and the boreal region may be the location of a large positive feedback on global climate change. 5120,1999,2,4,Seasonal variation in nutrients| pelagic primary production and grazing in a high-Arctic coastal marine ecosystem| Young Sound| Northeast Greenland,The Young Sound estuary was covered by sea ice for approximately 10 mo during 1996. Investigations of pelagic primary production and estimated grazing were performed during the summer thaw (20 June to 25 August) and in the winter month of February. The phytoplankton community was dominated by diatoms in the surface samples| as well as in the subsurface bloom succeeding the spring bloom. Pelagic primary production was limited by light during sea ice cover. After break-up of the sea ice| silicate initially Limited primary production in the surface water due to a well-established pycnocline| and maximum photosynthesis occurred in a subsurface layer at 15 to 20 m depth. In August| production sank to deeper water layers presumably due to nitrogen limitation. The carbon budget describing the fate of the annual pelagic primary production in Young Sound reveals that the pelagic production of similar to 10 g C m(-2) yr(-1) was lightly coupled to the grazer community| since total consumption by the grazer community amounted to 10-12 g C m(-2) yr(-1). The classical food web dominated this northeastern Greenlandic fjord| and it was estimated that copepods account for >80% of the grazing pressure upon phytoplankton. Based on this study and other values of annual pelagic primary production and sea ice cover found in the literature| we suggest that annual pelagic primary production in the Arctic can be described as proportional to the length of the open water Light period. We propose that annual pelagic primary production| and hence secondary production| in a wide range of Arctic marine areas may increase in the future as a consequence of reduction and thinning of sea ice cover due to global warming. 5057,1999,2,4,Seasonality of streamflow: The upper Mississippi River,The understanding of seasonal variations in streamflow is important for water resource management. The dynamics of streamflow are often dominated by annual and intra-annual variations| and the global warming debate has also generated an interest in potential changes in the seasonal cycle of hydroclimatic variables. Thus there are mechanistic as well as policy motivations for an empirical analysis of the historical seasonal variations in streamflow. The seasonality of the upper Mississippi River streamflow is investigated in this paper using a 123-year record of daily flow. This long streamflow series provides an interesting look at the high- and low-flow seasons within the year| their interannual variation| and within-season attributes. Evidence for changes in the timing and amplitude of these seasons and the annual flow extremes is presented. Connections to similar trends in regional climate variables are noted. The upper Mississippi River streamflow exhibits bimodal probability distributions for monthly averages and for specific seasons. Transitions across the high- and low-flow regimes corresponding to these modes exhibit memory across seasons and over years. Thus an empirical basis for seasonal or longer prediction is provided. Needs for developing a mechanistic explanation of the empirical observations offered are also indicated. 4963,1999,3,3,Secondary benefits of greenhouse gs control: Health impacts in China,In addition to long-term benefits of greenhouse gas (GHG) reductions in the form of avoided health and ecosystem damage| there are important near-term benefits resulting from the reduction in health-damaging pollutants (HDP) that can accompany GHG reductions. This paper estimates such health benefits| using the power and household energy sectors of China as a case study for the method. Four policy scenarios were compared: business as usual| least-cost energy efficiency| least-cost per unit global-warming-reduction fuel substitution| and least-cost per unit exposure-reduction fuel substitution. The health benefits were estimated by converting PM10 emissions first to human exposures and then to avoided mortality and morbidity with existing exposure-response relationships. Our results demonstrate that the near-term health benefits from GHG reductions in China could be substantial but are highly dependent on the technologies and sectors chosen. Such near-term benefits provide the opportunity for a true "no-regrets" GHG reduction policy. The results of this study also have important implications for the current international negotiations to cut GHG emissions by demonstrating that GHG reduction strategies can have substantial local and national as well as global benefits. 4941,1999,3,3,Selection of appropriate greenhouse gas mitigation options,Greenhouse gas mitigation options help in reducing greenhouse gas emissions so as to avoid the adverse environmental impacts due to global warming/climate change. They have different characteristics when evaluated using different criteria. For example| some options may be very cost effective| while some may have an additional advantage of reducing local pollution. Hence| selection of these options| for consideration by a national government or by a funding agency| has to incorporate multiple criteria. In this paper| some important criteria relevant to the selection are discussed| and a multi-criteria methodology is suggested for making appropriate selection. The methodology| called the Analytic Hierarchy Process| is described using two illustrations. (C) 1999 Elsevier Science Ltd. All rights reserved. 5009,1999,4,3,Semiconductor and thin film applications of a quadrupole mass spectrometer,Commercial quadrupole mass spectrometer (QMS) residual gas analyzers became available in the late 1960s and have been popular in R&D laboratories| but have found limited use in semiconductor manufacturing. To sample at pressures above 10(-5) Torr with ppm sensitivity or better (relative to the total process pressure)| differential pumping is usually required. The newly available| small| high-pressure QMS sensors can operate as high as 10-20 mTorr without differential pumping| but provide somewhat lower mass resolution and partial pressure sensitivity than a standard QMS. Applications in semiconductor manufacturing include equipment monitoring| process monitoring| and effluent analysis. Equipment monitoring can include qualification after preventative maintenance| rate-of-rise tests| and leak identification and detection. Usually the burning question is| Why won't the vacuum chamber pump down? Other uses that are not usually considered include the qualification of replaceable parts: sputter cathodes| electrodes| lamps| shields| etc. In process monitoring| the key question is| Is this process running normally? A manufacturing monitor can be useful simply by providing a comparison between a well-behaved high-yield process and a marginal or failing process. Examples are given for physical vapor deposition (sputtering) processes| chemical vapor deposition| and plasma etching. The effluent from chemical vapor deposition and plasma etch processes can be analyzed to measure the efficiency of process gas utilization or to monitor the efficacy of abatement methods used for the removal of global warming gases. (C) 1999 American Vacuum Society. [S0734-2101(99)04704-1]. 4907,1999,2,3,Sensitivity of stream temperatures in the United States to air temperatures projected under a global warming scenario,To project mean weekly stream temperature changes in response to global climate warming and for studies of freshwater ecosystems| a four-parameter nonlinear function of weekly air temperatures was used. One parameter| the upper bound stream temperature| was obtained by extreme value analysis from stream temperature data| and the other three parameters were obtained by least squares regression analysis. The least squares regression function was developed separately for the warming season and the cooling season (hysteresis) to take heat storage due to snowmelt or reservoir operations into account. There were very weak correlations between model parameters and annual or seasonal air temperatures. To project weekly stream temperatures under a 2 X CO2 climate scenario| weekly air temperature data from 166 weather stations| incremented by the output of the Canadian Center of Climate Modelling (CCC) general circulation model (GCM)| were applied to nonlinear stream temperature models developed for 803 stream gaging stations. An error analysis indicated that only 39 stream gaging stations would not exhibit a significant change under the CCC-GCM 2 X CO2 climate scenario. The projections at the remaining 764 stream gaging stations showed that mean annual stream temperatures in the contiguous United States would increase by 2 degrees-5 degrees C| least near the West Coast and most in the Missouri River and Ohio River basins. On average| there would be a 1 degrees-3 degrees C increase in the maximum and minimum weekly stream temperatures under the 2 X CO2 climate scenario| most in the central United States. It was also found that most streams would experience the maximum change in weekly stream temperatures in spring (March-June). The minimum changes in stream temperatures are projected to occur in winter (December and January) and summer (July and August) throughout the United States. 2236,1999,2,4,Sex- and habitat-specific responses of a high arctic willow| Salix arctica| to experimental climate change,Dioecious plant species and those occupying diverse habitats may present special analytical problems to researchers examining effects of climate change. Here we report the results from two complementary studies designed to determine the importance of sex and habitat on gas exchange and growth of male and female individuals of a dioecious| circumpolar willow| Salix arctica| in the Canadian High Arctic. In field studies| male and female willows from dry and wet habitats were subjected to passively enhanced summer temperature (similar to 1.3 degrees C) using small open-top chambers over three years. Peak season gas exchange varied significantly by willow sex and habitat. Overall net assimilation was higher in the dry habitat than in the wet| and higher in females than in males. In the dry habitat| net assimilation of females was enhanced by experimental warming| but decreased in males. In the wet habitat| net assimilation of females was substantially depressed by experimental warming| while males showed an inconsistent response. Development and growth of male and female catkins were enhanced by elevated temperature more than leaf fascicles| but leaf fascicle development and growth varied more between the two habitats| particularly in males. In a controlled environment study| male and female willows from these same wet and dry habitats were grown in a 2x2 factorial experiment including 1 x or 2 x ambient [CO2] and 5 or 12 degrees C. The sexes responded very differently to the experimental treatments| but we found no effect of original habitat. Net assimilation in males was affected by the interaction of temperature and CO2| but in females by CO2 only. Our results demonstrate (a) significant intraspecific and intersexual differences in arctic willow physiology and growth| (b) that these differences are affected by environmental conditions expected to accompany global climate change| and (c) that sex- and habitat-specific responses should be explicitly accounted for in studies of dioecious species. 5096,1999,4,2,Short-term climatic fluctuations and the interpretation of recent observations in terms of greenhouse effect,Simulations of future climate made with coupled general circulation models of the atmosphere and ocean predict that the increase of the concentration of greenhouse gases released in the atmosphere by man's activities will have a large influence on the climate of the next century. The identification of the climatic impact produced by the rapid increase in carbon dioxide concentration in the last decades is made difficult by strong interannual climate variability| and requires the application of statistical techniques combining several climatic indicators (method of climatic "fingerprints") so as to improve the detection of a possible anthropogenic perturbation. In this paper we review the evolution through the last decades of several climate indicators showing global warming| its geographical distribution| sea level| the hydrological cycle and the response of vegetation| and Rie compare them to the model results predicted in climate scenarios. The coherence between model results and observed climatic trends shows that: the additional greenhouse effect is starting to become detectable in recent climatic data. ((C) Academie des sciences / Elsevier| Paris). 5035,1999,2,4,Signals of climate trends and extreme events in the thermal stratification pattern of multibasin Lake Opeongo| Ontario,Previous empirical observations on thermocline response to warmer conditions have been contradictory. Given that a deepening thermocline was observed for a small lake (0.5 km(2)) and a shallowing thermocline was observed for a larger system (73.6 km(2))| these contradictions may be attributable to differences in lake size and the diminishing influence of water clarity on mixing depth. The four basin systems of Lake Opeongo| Ontario| Canada| range in size from 4.4 to 22.1 km(2) and build an empirical suite of stratification responses to climate variation for a wide range of lake sizes. From 1958 to 1996| lake temperature profiles were taken in the four major basins of Lake Opeongo. Canonical correlation analyses linked earlier iceout dates| warm July-August air temperatures| and relatively high amounts of bright sunshine in July and August with warmer midsummer epilimnia and shallower midsummer thermoclines for all four basins. The occurrence of stratification patterns associated with warmer climatic conditions increased (r = 0.44| p < 0.01) in parallel with the recent (post-1965) global warming trend. Such patterns also tended to occur in El Nino years. Stratification conditions with cooler midsummer epilimnia and deeper thermoclines tended to occur in La Nina years and provided a pronounced signal in 1992| the year that experienced a global cooling effect due to the eruption of Mount Pinatubo. 5050,1999,4,4,Signature of recent climate change in frequencies of natural atmospheric circulation regimes,A crucial question in the global-warming debate concerns the extent to which recent climate change is caused by anthropogenic forcing or is a manifestation of natural climate variability(1). It is commonly thought that the climate response to anthropogenic forcing should be distinct from the patterns of natural climate variability. But| on the basis of studies of nonlinear chaotic models with preferred states or 'regimes'| it has been argued(2|3) that the spatial patterns of the response to anthropogenic forcing may in fact project principally onto modes of natural climate variability. Here we use atmospheric circulation data from the Northern Hemisphere to show that recent climate change can be interpreted in terms of changes in the frequency of occurrence of natural atmospheric circulation regimes. We conclude that recent Northern Hemisphere warming may be more directly related to the thermal structure of these circulation regimes than to any anthropogenic forcing pattern itself. Conversely| the fact that observed climate change projects onto natural patterns cannot be used as evidence of no anthropogenic effect on climate. These results may help explain possible differences between trends in surface temperature and satellite-based temperature in the free atmosphere(4-6). 4933,1999,3,3,Silicon oxide selective etching process keeping harmony with environment by using radical injection technique,A novel radical control method using a radical injection technique was proposed for preventing global warming. This system consists of a new fluorocarbon radical source where-the polytetrafluoroethylene was ablated by a CO2 laser resulting in producing fluorocarbon radicals working as etching species and a radical filter set in front of the radical source which controls radicals generated from the radical source. Therefore| this system does not employ any fluorocarbon feed gases causing the global warming. The system was successfully applied to SiO2 over Si selective etching process employing an electron cyclotron resonance plasma. CFx (x = 1-3) radical densities| F atom densities and higher species were successfully controlled by using the radical filter| which was confirmed by an infrared diode laser absorption spectroscopy and an actinometric optical emission spectroscopy. From these results| it was found that this technique was applicable to SiO2 over Si selective etching process keeping harmony with the environment| particularly for preventing global warming. (C) 1999 American Vacuum Society. [S0734-2101(99)02106-5]. 5114,1999,2,4,Simulated climate change affecting microorganisms| nematode density and biodiversity in subarctic soils,Arctic terrestrial ecosystems are strongly dominated by temperature| and global warming is expected to have a particularly strong impact in high latitudes. The Arctic will therefore be an important region for early detection of global change. In the present study the effects of environmental manipulations simulating climate change on soil microorganisms and nematode populations were investigated. Study sites were a dwarf shrub dominated tree-line heath (450 m a.s.l.) and a high altitude fellfield (1150 m a.s.l.) at Abisko| Swedish Lapland. Soil temperature was enhanced by using passive greenhouses and the impact on soil organisms with and without NPK fertilizer addition was assessed. The nematode community was strongly affected by warming and nutrient application. Population density was twice as high for all treatments at the fellfield as compared to controls. At the heath temperature enhancement with or without fertilizer application also led to a doubling of the population density| whereas fertilization alone caused an increase of about one third. The environmental manipulations resulted in a greater microbial biomass C and active fungal biomass in the heath soil. Increased density was also recorded for bacterial and fungal feeding nematodes at both sites. The results suggest that nematodes have an important impact on microbial biomass and turnover rates in the two subarctic systems. Elevated soil temperature apparently will lead to increased grazing on microorganisms| contributing to enhanced net N and P mineralization rates and plant nutrient availability. However| biodiversity was generally affected negatively by the environmental manipulations. The effects were more severe at the high altitude fellfield indicating that the influence of elevated temperature will be more pronounced in systems already stressed by extreme climatic conditions. 4995,1999,2,4,Simulated climate change in subarctic soils: responses in nematode species composition and dominance structure,The nematode fauna at two contrasting subarctic sites was studied at Abisko| Swedish Lapland. One site was a dwarf shrub dominated| tree-line heath (450 m a.s.l.) and the other a high altitude fellfield (1150 m a.s.l.). Responses in the composition of the nematode fauna to eight growing seasons with simulated climate change were monitored. The environmental manipulations consisted of temperature increase by using passive greenhouses| NPK fertilization| and a combination of both. A total of 98 species was found at the sites| with twice as many species at the heath compared to the climatically harsh fellfield. Species similarity was low| most likely due to differences in soil type and vegetation cover. The environmental perturbations caused distinct changes in dominance and trophic structure. Taxa common at both sites responded similarly with increases in Aphelenchoides| Filenchus and Plectus| and decreases in Eudorylaimus| Monhystrella and Teratocephalus. Generally| the manipulations changed the trophic composition in favour of fungal and plant feeding species| indicating a shift in the decomposition pathway. 4964,1999,4,4,Simulation of daily temperatures for climate change scenarios over Portugal: a neural network model approach,Methods to assess the impact of global warming on the temperature regime of a single site are explored with reference to Coimbra in Portugal. The basis of the analysis is information taken from a climate change simulation performed with a state-of-the-art general circulation model (the Hadley Centre model). First| it is shown that the model is unable to reproduce accurately the statistics of daily maximum and minimum temperature at the site. Second| using a re-analysis data set| downscaling models are developed to predict site temperature from large-scale free atmosphere variables derived from the sea level pressure and 500 hPa geopotential height fields. In particular| the relative performances of linear models and non-linear artificial neural networks are compared using a set of rigorous validation techniques. It is shown that even a simple configuration of a 2-layer non-linear neural network significantly improves on the performance of a linear model. Finally| the non-linear neural network model is initialised with general circulation model output to construct scenarios of daily temperature at the present day (1970-79) and for a future decade (2090-99). These scenarios are analysed with special attention to the comparison of the frequencies of heat waves (days with maximum temperature greater than 35 degreesC) and cold spells (days with minimum temperature below 5 degreesC). 2234,1999,4,3,Simulations of forest system response and feedbacks to global change: experiences and results from the US Country Studies Program,Large shifts in the response and feedbacks of forest systems are implied by models and systems analysis driven by global change scenarios of general circulation models (GCMs). Prior climate change analyses and modeling efforts have been reported at a global scale in a few developed countries| but relatively few national assessments have been successfully completed in developing countries. Under the auspices of the U.S. Country Studies Program| analysts from 55 countries employed a common set of methods and models to characterize current carbon (C) pools in forests| future impacts of global change on forest distribution| and management options for conserving and sequestering carbon dioxide (CO(2)) in forest systems. The analysis revealed that the response and feedbacks of forest systems to global climate change will be profound in the 55 countries studied on five continents. Globally| forest vegetation and soils contain about 1146 Pg C| with approximately 37% of this C in low-latitude forests| 14% in mid-latitudes| and 49% at high latitudes. The impacts of future global change on forest distribution and productivity will be most significant at high latitudes| with more modest changes in distribution and productivity at low latitudes. Future opportunities to conserve and sequester CO(2) in forest systems are potentially significant| but land-use practices and global change will influence the size of this C pool and CO(2) sink. In the future| a greater proportion of forests at all latitudes could become a greenhouse gas (GHG) source if sustained management and conservation policies are not employed. The timing and magnitude of future changes in forest systems are dependent on global environmental factors (for example| global change| biogeochemical Sulphur and Nitrogen cycles)| as well as on human factors such as demographics| economic growth| technology| and resource management policies. (C) 1999 Elsevier Science B.V. All rights reserved. 5111,1999,4,2,Simulations of Southern Hemisphere warming and Antarctic sea-ice changes using global climate models,A combination of modelling techniques is used in conjunction with the limited available observational data to examine Antarctic sea-ice changes with global warming over the past century. Firstly| a coupled global climate model is forced by prescribing the effect of increasing greenhouse gases from last century to the present. Secondly| the GISST (U.K| Meteorological Office global sea-ice and sea surface temperature) observational dataset is used to force an atmosphere-sea-ice model to compute changes in the Antarctic sea ice from last century to the present. Thirdly| the global sea-surface-temperature (SST) anomalies derived from the coupled model are used to force the atmosphere-sea-ice model over the same period. The change in the Southern Hemisphere annual mean surface temperature simulated by the coupled model with greenhouse-gas forcing is about 0.6 degrees C| which is similar to the observed change. Over the Antarctic (poleward of 60 degrees S) the corresponding simulated change is about 0.7 degrees C| which also appears compatible with observations. The reduction in summer sea-ice extent simulated by the CSIRO (Commonwealth Scientific and Industrial Research Organisation) coupled model is 0.44 degrees lat. which is| in general| less than the observed change. For the two SST forcing cases the changes are| in general| larger than indicated by the observations. It is concluded that future changes of reduced sea-ice extent from increasing greenhouse gases as simulated by the CSIRO coupled model are not expected to be overestimates. 4919,1999,2,3,Snow characterization using SSM/I data,Snow in the Himalayan region is a vital water resource for India. Most of the river systems of India are dependent on melting of snow during summer months| which gives substantial amount of water for agriculture and hydropower| and a boost to our development. But the changes in snow cover have direct relation to global climatic changes. It is expected that the surface and atmospheric temperatures may significantly change which may influence the snow cover over high altitude regions. Currently| much attention is being paid to the global warming trend due to the increase of greenhouse gases in the earth's atmosphere. The mapping of snow cover using optical sensors| however| suffers quite often with cloud problems. Such problems do not affect microwave remote sensing which has an added advantage of quantitative estimation of snow parameters and characterization of snow cover. In the present work| an attempt has been made to study the characteristics of brightness temperature of snow over Himalayan region using SSM/I data. 4944,1999,3,3,Soil and residue management effects on cropping conditions and nitrous oxide fluxes under controlled traffic in Scotland 2. Nitrous oxide| soil N status and weather,Nitrogen from fertilisers and crop residues can be lost as nitrous oxide N2O)| a greenhouse gas that causes an increase in global warming and also depletes stratospheric ozone. Nitrous oxide emissions| soil chemical status| temperature and N2O concentration in the soil atmosphere were measured in a field experiment on soil compaction in loam and sandy loam (cambisols) soils in south-east Scotland. The overall objective was to discover how the intensity and distribution of soil compaction by tractor wheels or by roller just before sowing influenced crop performance| soil conditions and production and emissions of N2O under controlled traffic conditions. Compaction treatments were zero| light compaction by roller (up to 1 Mg per metre of length) and heavy compaction by loaded tractor (up to 4.2 Mg). In this paper we report the effects on production and emissions of N2O and relate them to soil and crop conditions. Nitrous oxide fluxes were substantial only when the soil water content was high (>27 g per 100 g). Fertiliser application stimulated emissions in the spring whereas crop residues stimulated emissions in autumn and winter. Heavy compaction increased N2O emissions after fertiliser application or residue incorporation more than light or zero compaction. The bulk densities of the heavily and lightly compacted soils were up to 89% and 82% of the theoretical (Proctor) maxima. Higher soil cone resistances| temperatures and nitrogen availability and lower gas diffusivities and air-filled porosities combined to make the heavily compacted soil more anaerobic and likely to denitrify than the zero or lightly compacted soil. Compaction sufficient to increase N2O emissions significantly corresponded with adverse soil conditions for winter barley (Hordeum vulgare L.) growth. Soil tillage| which ensures that soil compaction is no greater than in our light treatment and is confined to near the soil surface| may help to mitigate both surface fluxes of N2O and losses to the subsoil. (C) 1999 Elsevier Science B.V. All rights reserved. 5015,1999,4,4,Soil protozoa as bioindicators: pros and cons| methods| diversity| representative examples,This paper emphasizes some general aspects of soil protozoa as indicators of environmental quality-pros and cons| methods| and diversity. Protozoa are at the base of the heterotrophic eukaryotic food web and an essential component in marine| freshwater| and soil ecosystems because they consume a significant portion (usually >50%) of the bacterial productivity. enhancing nutrient cycles and energy flows to the benefit of microorganisms| plants and animals. Accordingly| studies of their dynamics and community structures provide a powerful means for assessing and monitoring changes in the biotic and abiotic environment. This is exemplified by some representative studies focusing on soil oxygen regime| differentiation of humus types| pesticides| global warming| forest decline| movement of protozoan pathogens in soil| and soil protozoan bioassays. Usually| protozoa are not replaceable by higher animals (meso- and macrofauna) as indicator organisms because they have unique physiological properties: they consume more food and have a higher respiration rate per mass unit| have shorter generation and life times| and reproduce much faster. Direct counting methods should be given preference over dilution culture techniques| which are beset with uncontrollable deficiencies. Thus| ciliates and| especially| testate amoebae| whose abundance and diversity can be reliably estimated in simple soil suspensions| should be preferred in environmental studies. About 1600 protozoan species are known to live in terrestrial habitats. However| data from studies of ciliates suggest that this is only a minor portion (20-30%) of the species actually present| most of which are still undescribed. Overcoming the methodological and taxonomic problems are urgent needs which| at present| limit the use of protozoa as bioindicators in terrestrial environments. Furthermore| species monographs are required to compile the taxonomic| faunistic| and ecological information available. (C)1999 Elsevier Science B.V. All rights reserved. 5104,1999,2,4,Soil warming and carbon loss from a lake states spodosol,Elevated soil temperatures may increase C loss from soils by accelerating microbial respiration and dissolved organic C leaching. We evaluated the effect of elevated soil temperatures on C losses from a forest Spodosol by incubating soil cores from surface (Oa + A + E) and subsurface (Bhs) horizons at two seasonal temperature regimes. One regime simulated the normal course of soil temperatures in northern lower Michigan| and the other simulated soil temperatures representing an amount of warming that might occur under some global warming theory calculations. We measured the amounts of CO2-C respired and dissolved organic C leached from the soil cores during a 33-wk period. Microbial respiration rates| after adjustment for variation in initial rates| were significantly increased by soil warming and were greater in surface than in subsurface horizons. Warming significantly increased cumulative C respired| with greater losses from surface soils (greater than or equal to 50 mg C g(-1) C) as compared with subsurface soils (less than or equal to 25 mg C g(-1) C). Mean quantities of dissolved organic C leached| ranging from 2.3 to 3.2 mg C g(-1) C| did not differ significantly by soil horizon or temperature regime. Increased microbial respiration in surface soil horizons was the process most responsive to soil warming in the Spodosol samples we examined. Whether this is a short-term effect that would disappear once pools of labile C are exhausted| or represents a long-term response to soil warming| remains uncertain. 2250,1999,4,4,Solar cycle length and 20th century Northern Hemisphere warming: Revisited,It has been suggested that the length of the solar cycle (SCL) is related to solar forcing of global climate change [Fris-Christensen and Lassen| 1991]. Although no physical mechanism had been proposed| the relation seemed to be supported by interesting correlations with several paleoclimate records and| separately| with the 20th century Northern Hemisphere instrumental record. Actually| what has been correlated is the quasi-sinusoidal Gleissberg cycle which is slightly greater in the 18th century than in the 20th century. Using the pre-industrial record as a boundary condition| the SCL-temperature correlation corresponds to an estimated 25% of global warming to 1980 and 15% to 1997. 2231,1999,4,4,Sources of variability in net primary production predictions at a regional scale: A comparison using PnET-II and TEM 4.0 in northeastern US forests,Because model predictions at continental and global scales are necessarily based on broad characterizations of vegetation| soils| and climate| estimates of carbon stocks and fluxes made by global terrestrial biosphere models may not be accurate for every region. At the regional scale| we suggest that attention can be focused more clearly on understanding the relative strengths of predicted net primary productivity (NPP) limitation by energy| water| and nutrients. We evaluate the sources of variability among model predictions of NPP with a regional-scale comparison between estimates made by PnET-II (a forest ecosystem process model previously applied to the northeastern region) and TEM 4.0 (a terrestrial biosphere model typically applied to the globe) for the northeastern US. When the same climate| vegetation| and soil data sets were used to drive both models| regional average NPP predictions made by PnET-II and TEM were remarkably similar| and at the biome level| model predictions agreed fairly well with NPP estimates developed from field measurements. However| TEM. 4.0 predictions were more sensitive to regional variations in temperature as a result of feedbacks between temperature and belowground N availability. In PnET-II| the direct link between transpiration and photosynthesis caused substantial water stress in hardwood and pine forest types with increases in solar radiation; predicted water stress was relieved substantially when soil water holding capacity (WHC) was increased. Increasing soil WHC had little effect on TEM 4.0 predictions because soil water storage was already sufficient to meet plant demand with baseline WHC values| and because predicted N availability under baseline conditions in this region was not limited by water. Because NPP predictions were closely keyed to forest cover type| the relative coverage of low- versus high-productivity forests at both fine and coarse resolutions was an important determinant of regional NPP predictions. Therefore| changes in grid cell size and differences in the methods used to aggregate from fine to coarse resolution were important to NPP predictions insofar as they changed the relative proportions of forest cover. We suggest that because the small patches of high-elevation spruce-fir forest in this region are substantially less productive than forests in the remainder of the region| more accurate NPP predictions will result if models applied to this region use land cover input data sets that retain as much fine-resolution forest type variability as possible. The differences among model responses to variations in climate and soil WHC data sets suggest that the models will respond quite differently to scenarios of future climate. A better understanding of the dynamic interactions between water stress| N availability| and forest productivity in this region will enable models to make more accurate predictions of future carbon stocks and fluxes. 2272,1999,2,4,Statistical models of invertebrate distribution on Macquarie Island: a tool to assess climate change and local human impacts,Sub-Antarctic islands are good model systems in which to study the ecological effects of human impacts| particularly global climate change and alien species. Invertebrates form a central component of these ecosystems. We conducted a stratified survey of 69 sites on sub-Antarctic Macquarie Island and used logistic regression models to describe the distribution of 14 abundant invertebrate species. We also developed a statistical model of windspeed based on topography. The distributions of individual species were described by different combinations of aspect| altitude and vegetation type. Ordination of sites based on species composition showed strong effects of altitude and vegetation on invertebrate assemblages. The species distribution models provide a tool for detecting| monitoring and predicting effects of climate change and alien species on biota and ecosystem processes. 4979,1999,3,4,Steps towards an environmentally sustainable transport system,Motorists may assist in going towards sustainable transport if given a wider basis for choice between vehicles| to include a number of important environmental aspects. (C) 1999 Elsevier Science B.V. All rights reserved. 2267,1999,2,4,Stream temperature air temperature relationship: a physical interpretation,In studies of the potential effects of global climate change on freshwater ecosystems| water temperature is a primary factor. Linear regressions of stream temperature versus air temperature are attractive for this purpose| because they require only one input variable (air temperature) which can be simulated by General Circulation Models (GCMs) better than other climate variables. Under a warmer climate scenario| high stream temperatures must be projected by extrapolation. The question arises whether linear extrapolation is valid. To answer the question| the heat exchange processes that contribute to surface water temperature have been analyzed and related to air temperature on a weekly time scale. The equilibrium temperature concept introduced by Edinger has been used. In stream reaches with large drainage area| stream temperature can be approximated by equilibrium temperature. At elevated air temperatures| the vapor pressure deficit above a water surface increases drastically (even in humid regions) causing strong evaporative cooling and hence a flatter stream temperature/air temperature relationship. At low air temperatures| stream temperatures often reach 0 degrees C as an asymptote. If an upstream flow control (dam| reservoir release) or a waste heat input is present| the lower asymptotic value can be larger than 0 degrees C. As a result of these upper and lower constraints for stream temperatures| the stream temperature/air temperature relationship resembles an S-shaped function rather than a straight line. Linear extrapolations to high and low air temperatures are therefore not justified. (C) 1999 Elsevier Science B.V. All rights reserved. 5117,1999,4,3,Surface radiation fluxes in transient climate simulations,Transient CO2 experiments from five coupled climate models| in which the CO2 concentration increases at rates of 0.6-1.1% per annum for periods of 75-200 years| are used to document the responses of surface radiation fluxes| and associated atmospheric properties| to the CO2 increase. In all five models| the responses of global surface temperature and column water vapour are non-linear and fairly tightly constrained. Thus| global warming lies between 1.9 and 2.7 K at doubled| and between 3.1 and 4.1 K at tripled| CO2| whilst column water vapour increases by between 3.5 and 4.5 mm at doubled| and between 7 and 8 mm at tripled| CO2. Global cloud fraction tends to decrease by 1-2% out to tripled CO2| mainly the result of decreases in low cloud. Global increases in column water| and differences in these increases between models| are mainly determined by the warming of the tropical oceans relative to the middle and high latitudes; these links are emphasised in the zonal profiles of warming and column water vapour increase| with strong water vapour maxima in the tropics. In all models the all-sky shortwave flux to the surface S-down arrow (global| annual average) changes by less than 5 W m(-2) out to tripled CO2| in some cases being essentially invariant in time. In contrast| the longwave flux to the surface L-down arrow increases significantly| by 25 W m(-2) typically at tripled CO2. The variations of S-down arrow and L-down arrow (clear-sky and all-sky fluxes) with increase in CO2 concentration are generally non-linear| reflecting the effects of ocean thermal inertia| but as functions of global warming are close to linear in all five models. This is best illustrated for the clear-sky downwelling fluxes| and the net radiation. Regionally| as illustrated in zonal profiles and global distributions| greatest changes in both S-down arrow and L-down arrow are the result primarily of local maxima in warming and column water vapour increases. (C) 1999 Elsevier Science B.V. All rights reserved. 5020,1999,3,3,Surface wave plasma abatement of CHF3 and CF4 containing semiconductor process emissions,Projected exponential growth in semiconductor device manufacture over the next few years demands technology to reduce the corresponding increase in etchants such as perfluorocompounds (PFCs)| CHF3| and SF6 that would be emitted into the atmosphere. These compounds are a cause for concern because of their large global warming potentials relative to CO2 and of their long lifetimes in the atmosphere| often tens of thousands of years. We demonstrate that a plasma-based technology can yield effective (up to 99.9%) destruction and removal efficiencies (DREs) for CF4 and CHF3 present in etch recipes widely used in the semiconductor industry. Specifically| we report application of surface wave plasmas at 2.45 GHz for this purpose. Post-plasma effluent analysis included the determination of DREs and product distributions| simultaneously by gas-phase FTIR and QMS. Application of microwave powers from 500 to 1950 W were investigated and DREs for CF4 and CHF3 reported. Final product analysis indicated that PFC conversion was limited to low molecular weight gases such as CO2| CO| COF2| H2O| and HF. These investigations demonstrate that surface wave plasma destruction of the referenced PFCs at the output of semiconductor etch tools is a viable nonintrusive point of use abatement technology. 5121,1999,5,3,Tectonically-induced icehouse-greenhouse climate oscillations during the transition from the Variscan to the Alpine cycle (Carboniferous to Triassic),Remarkable global climate oscillations were recorded during the timespan middle Carboniferous-Triassic| which allows definition of two cold (icehouse 1 : middle Carboniferous; icehouse 2: early Permian) and two warm episodes (greenhouse 1: late Carboniferous - earliest Permian; greenhouse 2: middle Permian - Triassic). The tectonic evolution of the central Pangean realm from Variscan to late Variscan| and finally to early Alpine offers an explanation for these climate oscillations| in terms of mountain building| extensional collapse| rifting| epeirogeny| volcanism| erosion| and exhumation. The cold periods were associated with orogenic (icehouse 1) or epeirogenic (icehouse 2) movements leading to uplift and erosion| and therefore| to CO2 output from the atmosphere. On the contrary| the warm periods were related to extension-related phenomena| such as volcanism| deep- and shallow-seated hydrothermal activity| unroofing of large-scale metamorphic core-complexes (greenhouse 1)| or vast exhumation of coal and pear deposits and volcanism (greenhouse 2)| all of them processes leading to massive input of CO2 into the atmosphere| hence| to global warming. 5118,1999,2,4,Temperature| salinity and food effects on asexual reproduction and abundance of the scyphozoan Chrysaora quinquecirrha,Outbreaks of jellyfish are reported worldwide| yet the environmental factors that control the sizes of jellyfish populations are not well understood. The scyphomedusan Chrysaora quinquecirrha occurs in the mesohaline portion of Chesapeake Bay each summer. Population sizes of the medusae show dramatic annual variations that are correlated with salinity and temperature. We measured the total numbers of ephyrae and polyps produced by benthic polyps of C. quinquecirrha in laboratory experiments lasting 42 d| and found that temperature (15| 20| 25 degrees C) was not a statistically significant factor at low salinities (5 to 20 parts per thousand); however| ephyra production increased significantly with increasing temperature at high salinities (20 to 35 parts per thousand). Conversely| each 5 degrees C: decrease in temperature delayed strobilation (ephyra production) by about 1 wk. Salinity significantly affected the numbers of ephyrae and polyps produced in all experiments. Ephyra and polyp production was lower at both low (<11 parts per thousand) and high salinities (greater than or equal to 25 parts per thousand) than at intermediate salinities. Also| more ephyrae| but| not polyps| were produced with more available prey. Medusa numbers were 2 orders of magnitude lower in July 1996 when water temperatures| salinities| and zooplankton densities in Chesapeake Bay all were lower than in July 1995. The effects of these factors are important in understanding the changes caused by human activities in near-shore ecosystems| including effects of global warming| eutrophication| and reduction of commercial species. 5023,1999,2,4,The Arctic and Antarctic oscillations and their projected changes under global warming,The Arctic Oscillation (AO) and the Antarctic Oscillation (AAO) are the leading modes of high-latitude variability in each hemisphere as characterized by the first EOF of mean sea-level pressure. Observations suggest a recent positive trend in the AO and it is speculated that this may be related to global warming. The CCCma coupled general circulation model control simulation exhibits a robust and realistic AO and AAO. Climate change simulations for the period 1900-2100| with forcing due to greenhouse gases and aerosols| exhibit positive trends in both the AO and the AAO. The model simulates essentially unchanged AO/AAO variations superimposed on a forced climate change pattern. The results do not suggest that a simulated trend in the AO/AAO necessarily depends on stratospheric involvement nor that forced climate change will be expressed as a change in the occurence of one phase of the AO/AAO over another. This pattern of climate change projects exclusively on the AAO pattern in the southern hemisphere but not in the northern hemisphere where other EOFs are involved. The extent to which this forced climate change pattern and the unforced modes of variation are determined by the same mechanisms and feedbacks remains an open question. 4969,1999,3,4,The Carbon-tax debate,This paper discusses recent topics related indirectly to energy production and marketing and related highly to energy policy and economy. These topics are: (1) background to carbon taxes including environmental issues - global warming and CO2 emissions| fuel substitution and the encouragement of non-hydrocarbon fuel use; (2) climate-change convention and related conferences including those at Rio de Janeiro - objectives and achievements| and Kyoto-objectives; (3) carbon-tax proposals| including implications for oil| coal and gas: (4) The OECD view including evolution of general taxes on hydrocarbons| the carbon tax as a government revenue-raising objective| CO2 emissions in the OECD; (5) the oil-producer's view including discrimination against oil| the impact on the incentives to use oil and gas; (6) the developing countries' view| including the need to increase fuel use for industrialisation| financial constraints on energy use| and CO2 emissions in the developing countries. (C) 1999 Elsevier Science Ltd. All rights reserved. 5082,1999,2,4,The dynamics of zooxanthellae populations: A long-term study in the field,Coral bleaching characterized by the expulsion of symbiotic algae (zooxanthellae) is an increasing problem worldwide. Global warming has been implicated as one cause| but the phenomenon cannot be fully comprehended without an understanding of the variability of zooxanthellae populations in field conditions. Results from a 6-year field study are presented| providing evidence of density regulation but also of large variability in the zooxanthellae population with regular episodes of very Low densities. These bleaching events are Likely to be part of a constant variability in zooxanthellae density caused by environmental fluctuations superimposed on a strong seasonal cycle in abundance. 5004,1999,5,4,The Early Permian deglaciation event between East Africa and northwestern Australia,Late Palaeozoic glacigene deposits forming the base of the Gondwana megasequence are present along the entire length of the Tethyan margin of Gondwana. The lithology of the deposits in these sequences was controlled largely by the prevailing climate and this influence was imposed also upon early diagenesis. The change from the cold| glacial climate to the cool temperate| postglacial environment is reflected by a change from a mineralogically immature composition (arkosic chloritic) of the glacial periglacial sediments| to a mature| kaolinite pyrite quartz dominated lithofacies of the deglaciation deposits. A typical feature of the latter period is the appearance of black| kaolinitic lutites| usually with a high organic C content. From the many occurrences| only a few examples of typical deglaciation sequences are discussed in this paper| including Tanzania| southern Oman| the Lesser Himalaya| northwestern Australia and southwest China. Microflora and fauna demonstrate that all these deglaciation sequences are of Late Asselian to Early Sakmarian age| indicating that deglaciation along the Tethyan margin of Gondwana was| within the limit of the dating methods| a synchronuous event. A peak in sea level in the Late Sakmarian/Early Artinskian| experienced in all but one of the sections described| supports this statement. The high content of organic matter in the deglaciation deposits was caused by the sudden increase of bioproduction stimulated by higher temperatures and a high CO2 concentration in the atmosphere. A high input of organic material| combined with glacially overdeepened basin geometries| were responsible for the dominance of euxinic conditions during that period. The swift and synchronuous climatic amelioration cannot be explained by shifting pole positions| but only by rapid and substantial global warming. (C) 1999 Elsevier Science Limited. All rights reserved. 5084,1999,2,2,The effect of experimental ecosystem warming on CO2 fluxes in a montane meadow,Climatic change is predicted to alter rates of soil respiration and assimilation of carbon by plants. Net loss of carbon from ecosystems would form a positive feedback enhancing anthropogenic global warming. We tested the effect of increased heat input| one of the most certain impacts of global warming| on net ecosystem carbon exchange in a Rocky Mountain montane meadow. Overhead heaters were used to increase the radiative heat flux into plots spanning a moisture and vegetation gradient. We measured net whole-ecosystem CO2 fluxes using a closed-path chamber system| relatively nondisturbing bases| and a simple model to compensate for both slow chamber leaks and the CO2 concentration-dependence of photosynthetic uptake| in 1993 and 1994. In 1994| we also measured soil respiration separately. The heating treatment altered the timing and magnitude of net carbon fluxes into the dry zone of the plots in 1993 (reducing uptake by approximate to 100 g carbon m(-2))| but had an undetectable effect on carbon fluxes into the moist zone. During a strong drought year (1994)| heating altered the timing| but did not significantly alter the cumulative magnitude| of net carbon uptake in the dry zone. Soil respiration measurements showed that when differences were detected in dry zone carbon Fluxes| they were caused by changes in carbon input from photosynthesis| not by temperature-driven changes in carbon output from soil respiration. When differences were detected in dry-zone carbon fluxes| they were caused by changes in carbon input from photosynthesis| not by a temperature-driven changes in carbon output from soil respiration. Regression analysis suggested that the reduction in carbon inputs from plants was due to a combination of two soil moisture effects: a direct physiological response to decreased soil moisture| and a shift in plant community composition from high-productivity species to low-productivity species that are more drought tolerant. These results partially support predictions that warming may cause net carbon losses from some terrestrial ecosystems. They also suggest| however| that changes in soil moisture caused by global warming may be as important in driving ecosystem response as the direct effects of increased soil temperature. 2228,1999,2,3,The effects of climate change and irrigation on criterion low streamflows used for determining total maximum daily loads,This paper addresses the possible impacts of global climate change on low streamflows in the Midwest| both directly| through lower precipitation| and indirectly| by rendering irrigation profitable in areas where it has found little application in the past. In the analysis presented here| streamflow data are altered to represent the effect of climate change and stream-supplied irrigation| and then used to estimate new values for two low-flow criteria| the one- and seven-day-ten-year low flows ((7)Q(10) and (1)Q(10)) Under 20 climate change and irrigation scenarios. Additionally| the frequencies of violation of these two criteria| and multiple violations in a three-year period| are determined. Results show that the potential impact of the assumed climate change scenarios on low flow standards is substantial. A 25 percent decrease in mean precipitation results in a 63 percent reduction in design now| even in the absence of irrigation. With irrigation| the reduction can be as much as 100 percent. The frequency of single violations of low flow criteria is found to increase several fold with irrigation. The frequency of multiple violations of low flow criteria in a three-year period is sensitive to climate change| increasing from around 20 percent to nearly 100 percent as the climate change becomes more severe. 5045,1999,2,4,The effects of elevated summer temperature and sublethal pollutants (ammonia| low pH) on protein turnover in the gill and liver of rainbow trout (Oncorhynchus mykiss) on a limited food ration,Protein synthesis| degradation and growth of the liver and gills were determined in juvenile rainbow trout (Oncorhynchus mykiss) fed a limited ration and exposed for 90 days to normal or elevated summer temperatures (+2 degrees C above ambient) and either low pH (5.2) in softwater or 70 mu M total ammonia in hardwater. The limited ration resulted in low rates of growth (<0.80% per day) and protein synthesis in all fish. In softwater| whole-body growth was significantly inhibited by elevated temperature but stimulated by low pH| although tissue protein metabolism was generally unaffected by these treatments. There was no significant difference in final size between the groups of fish in hardwater| but liver protein synthesis and degradation were significantly lower at +2 degrees C| the reduction in synthesis being due to an inhibition of both the capacity for protein synthesis| C-s and the RNA translational efficiency| k(RNA). Gill protein metabolism was unaffected by the experimental treatments in trout in hardwater. The authors conclude that a global warming scenario would be detrimental to protein synthesis and growth in freshwater fish under conditions of food limitation in summer| and when late summer temperatures approached the upper thermal limit of the species| regardless of food availability. (C) 1999 Elsevier Science Inc. All rights reserved. 5132,1999,3,3,The ethics of burden-sharing in the global greenhouse,The Kyoto Protocol on global warming has provoked great controversy in part because it calls for heavier burdens on wealthy countries than on developing countries in the effort to control climate change. The U.S. Senate voted unanimously to oppose any agreement that does not require emissions reductions in low-income countries. The ethics of this position are examined in this paper which shows that there are good moral reasons for supporting the provisions of the Kyoto Protocol. Such a conclusion follows easily from considerations of distributive justice but can also be supported by more narrowly self-interested arguments. 2303,1999,4,4,The evolution of mass balance models of persistent organic pollutant fate in the environment,Current approaches to modelling the fate of persistent organic pollutants (POPs) in the environment have evolved in response to four dominant characteristics of these substances; namely: (1) the presence of POPs in virtually all environmental phases and the ease with which they move from one to the other requires multi-compartmental modelling. Describing transport across phase boundaries becomes as| or even more| important as quantifying transport within the phases; (2) POPs may persist in the environment for many decades. For chemicals that 'have time'| concepts such as equilibrium partitioning and steady-state become more important than for short-lived substances whose fate is more controlled by the rates of transformation; (3) measuring POPs is difficult and expensive and observed concentrations of POPs are not available in high spatial or temporal resolution. Consequently| high resolution tends not to be a high priority in POP models; and (4) detrimental effects of POPs often manifest themselves in top predators| which has led to a focus on modelling biotic uptake and transfer within food chains. The task of building a POPs model is viewed as combining the four 'building blocks' of partitioning| transport| transformation and source data with the help of the law of the conservation of mass. Process models| evaluative models| models of real local| regional and global fate| as well as biological uptake models are presented and references to numerous examples are provided. An attempt is made to forecast future directions in the field of POPs modelling. It is expected that modelling techniques that do not rely on quantitative emission estimates as well as approaches that take into account spatial| temporal and climatic variability as well as parameter uncertainty will increase in importance. Finally| the relationship between modelling POPs and models of other pollutant issues is addressed| as are potential interactions between POPs and pollutant issues such as eutrophication| acidification and global climate change. (C) 1999 Elsevier Science Ltd. All rights reserved. 5064,1999,3,3,The fate of CO2 hydrate released in the ocean,Disposal of anthropogenic CO2 in the ocean has been considered as a method to counteract global warming. A desirable method of the ocean disposal is to convert the less dense liquefied CO2 into denser CO2 hydrate via a submerged hydrate crystallizer at a depth < 500 m. The fate of CO2 hydrate in the ocean has been investigated. It is shown in this study that hydrate particles released in the ocean are physicochemically unstable; however| hydrate decomposition occurs only as a surface phenomenon. Because CO2 hydrate is denser than seawater| hydrate particles will sink in the ocean. During the descending process| the hydrate particles dissolve gradually in seawater owing to decomposition occurring continuously at surfaces of hydrate particles. This dissolution fate of CO2 hydrate in the ocean is significantly different from the previous prediction that the disposed CO2 hydrate would exist as a long-lasting entity in the ocean. Copyright (C) 1999 John Wiley & Sons| Ltd. 2285,1999,4,4,The frontier research system for global change - The International Arctic Research Center (Frontier-IARC): Its origin and tentative science plan,The Frontier Research System for Global Change-the International Arctic Research Center (Frontier-IARC) is a research program funded by the Frontier Research System for Global Change. The program is jointly run under a cooperative agreement between the Frontier Research System for Global Change and the University of Alaska Fairbanks. The aim of the program is to understand the role of the Arctic region in global climate change. The program concentrates its research effort initially on the areas of air-sea-ice interactions| bio-geochemical processes and the ecosystem. To understand the arctic climate system in the context of global climate change| we focus on mechanisms controlling arctic-subarctic interactions| and identify three key components: the freshwater balance| the energy balance| and the large-scab atmospheric processes. Knowledge of details of these components and their interactions will be gained through Long-term monitoring| process studies| and modeling; our focus will be on the Latter two categories. 2256,1999,2,4,The functional significance of leaf structure: a search for generalizations,The coupling between leaf structure and function is illustrated with reference to two examples| the C(4) photosynthetic pathway and leaf pubescence. A distinction is made between function and functional significance. The latter is defined as the role| significance or consequence of a structure| whereas the former is more simply the action that a structure is capable of performing. Using the two examples| four generalizations are made concerning the relationships between structure| function and functional significance: the functional significance of leaf structure is environment-dependent; the relationship between functional significance and structure is sometimes non-intuitive; functional equivalency means that there is often more than one 'solution' to the same 'constraint'; and the consequences of leaf structure can exert profound effects at levels of organization beyond those of the individual organism and may play a critical role in determining community structure and function| through interactions with other species and trophic levels. The importance of understanding the consequences in variation in leaf structure at the global scale is illustrated with reference to the issue of global climate change. 5025,1999,2,4,The influence of global warming in Earth rotation speed,The tendency of the atmospheric angular momentum (AAM) is investigated using a 49-year set of monthly AAM data for the period January 1949-December 1997. This data set is constructed with zonal wind values from the reanalyses of NCEP/NCAR| used in conjunction with a variety of operationally produced AAM time series with different independent sources and lengths over 1976-1997. In all the analyzed AAM series the linear trend is found to be positive. Since the angular momentum of the atmosphere-earth system is conserved this corresponds to a net loss of angular momentum by the solid earth| therefore decreasing the Earth rotation speed and increasing the length of day (LOD). The AAM rise is significant to the budget of angular momentum of the global atmosphere-earth system; its value in milliseconds/century (ms/cy) is +0.56 ms/cy| corresponding to one-third of the estimated increase in LOD (+1.7 ms/cy). The major contribution to this secular trend in AAM comes from the equatorial Tropopause. This is consistent with results from a previous study using a simplified aqua-planet model to investigate the AAM variations due to near equatorial warming conditions. During the same time interval| 1949-1997| the global marine + land-surface temperature increases by about 0.79 degrees C/cy| showing a linear correspondence between surface temperature increase and global AAM of about 0.07 ms per 0.1 degrees C. These results imply that atmospheric angular momentum may be used as an independent index of the global atmosphere's dynamical response to the|greenhouse forcing| and as such| the length of day may be used as an indirect indicator of global warming. 5071,1999,2,3,The influence of soil processes on carbon isotope distribution and turnover in the British uplands,Understanding the natural variation of carbon within the soil| and between soil types| is crucial to improve predictive models of carbon cycling in high and mid-latitude ecosystems in response to global warming. We measured the carbon isotope distributions (C-12| C-13 and C-14) in soil organic matter (SOM) from Podzols| Brown Podzolic soils and Stagnohumic Gleysols from the British uplands| which were then compared with the total amounts and turnover of carbon in these soils. We did so by sampling at 2-cm intervals down six profiles of each soil type. The average amount of carbon stored in the top 28 cm of the Stagnohumic Gleysols is twice that of the other two soils. The C-13 content and C-14 age show a general increase with depth in all soils| and there is also a significant correlation between isotopic variation and the main pedogenic features. The latter suggests that soil-forming processes are significant in determining the carbon isotope signatures retained in SOM. Organic matter formed since 1960 is not found below 5 cm in any of the soils. Evidently organic detritus in the surface layers (LF and Oh) is rapidly mineralized. This accords with our modelled net annual C fluxes which show that more than 80% of the CO2 emanating from these soils is derived from the top 5 cm of each profile. Although these soils contain much carbon| they do not appear to assimilate and retain SOM rapidly. The mean residence time of most of their carbon is in the 2-50 years range| so the soils are fairly ineffective sinks for excess CO2 in the atmosphere. Under the predicted future 'greenhouse' climate| likely to favour more rapid microbial decomposition of organic materials| these soils are a potential source of CO2 and are therefore likely to accelerate global warming. 5099,1999,4,4,The interannual change of atmospheric CO2: contribution of subtropical ecosystems?,The global terrestrial carbon cycle model CARAIB (CARbon Assimilation In the Biosphere) is used to study the response of the terrestrial ecosystems to the large scale climate variations over the period 1980-1993. The global net carbon exchange flux with the atmosphere is calculated and compared with the terrestrial contribution derived from the deconvolution of the atmospheric CO2 and delta(13)C measurements. A fairly large CO2 biospheric source is predicted during the strong El Nino events of 1982-83 and 1986-87 as a consequence of the induced global warming. The direct and indirect temperature controls of the primacy production and respiration dominate the CO2 anomaly. An analysis of the relative contribution by latitudinal bands and ecosystems shows that low-latitude vegetation dominates the variability at the El Nino time scale. In savannas| the model indicates that the interannual changes result| to a large extent| from the control of soil water content on gross primary production (GPP). In the tropical cain forests| both respiration and GPP contribute to the response of the net biospheric flux. 5116,1999,3,4,The marginal costs of greenhouse gas emissions,Estimates of the marginal costs of greenhouse gas emissions are an important input to the decision how much society would want to spend on greenhouse gas emission reduction. Marginal cost estimates in the literature range between $5 and $25 per tonne of carbon. Using similar assumptions| the FUND model finds marginal costs of $9-23/tC| depending on the discount rate. If the aggregation of impacts over countries accounts for inequalities in income distribution or for risk aversion| marginal costs would rise by about a factor of 3. Marginal costs per region are an order of magnitude smaller than global marginal costs. The ratios between the marginal costs of CO2 and those of CH4 and N2O are roughly equal to the global warming potentials of these gases. The uncertainty about the marginal costs is large and right-skewed. The expected value of the marginal costs lies about 35% above the best guess| the 95-percentile about 250%. 5133,1999,4,3,The NIST quantitative infrared database,With the recent developments in Fourier transform infrared (FTIR) spectrometers it is becoming more feasible to place these instruments in field environments. As a result| there has been enormous increase in the use of FTIR techniques for a variety of qualitative and quantitative chemical measurements. These methods offer the possibility of fully automated real-time quantitation of many analytes; therefore FTIR has great potential as an analytical tool. Recently| the U.S. Environmental Protection Agency (U.S.EPA) has developed protocol methods for emissions monitoring using both extractive and open-path FTIR measurements. Depending upon the analyte| the experimental conditions and the analyte matrix| approximately 100 of the hazardous air pollutants (HAPs) listed in the 1990 U.S.EPA Clean Air Act amendment (CAAA) can be measured. The National Institute of Standards and Technology (NIST) has initiated a program to provide quality-assured infrared absorption coefficient data based on NIST prepared primary gas standards. Currently| absorption coefficient data has been acquired for approximately 20 of the HAPs. For each compound| the absorption coefficient spectrum was calculated using nine transmittance spectra at 0.12 cm(-1) resolution and the Beer's law relationship. The uncertainties in the absorption coefficient data were estimated from the linear regressions of the transmittance data and considerations of other error sources such as the nonlinear detector response. For absorption coefficient values greater than 1 x 10(-4) mu mol/mol)(-1) m(-1) the average relative expanded uncertainty is 2.2 %. This quantitative infrared database is currently an ongoing project at NIST. Additional spectra will be added;to the database as they are acquired. Our current plans include continued data acquisition of the compounds listed in the CAAA| as well as the compounds that contribute to global warming and ozone depletion. 4949,1999,2,3,The potential impact of global warming on hail losses to winter cereal crops in New South Wales,This study was undertaken to determine the impact of potential global warming on the magnitude of hail losses to winter cereal crops within two areas situated on the western slopes of New South Wales| Australia. A model relating historical crop hail losses to climatic variables was developed for each area. These models included seasonal measures of vertical instability| low-level moisture and the height of the freezing level. In both areas| windshear was not found to be an important factor influencing seasonal crop hail losses. The two crop hail loss models were then used in conjunction with upper-air climatic data from three single mixed-layer global climate models (GCMs). Each GCM was run for 1 x CO2 conditions and for 2 x CO2 conditions. The enhanced greenhouse effect on climatic variables was taken to be the difference between their values for these two runs. Changes to climatic variables were then translated directly into changes in the percentage value of the winter cereal crop lost due to hail. In both areas| the three GCMs agreed concerning the direction of change in each of the variables used in the crop hail loss model. GCM simulations of the greenhouse effect resulted in a decline in winter cereal crop hail losses| with the exception of one GCM simulation at one location where losses increased slightly. None of the changes due to the enhanced greenhouse effect| however| were significant owing to a large observed seasonal variability of crop hail losses. Also| the simulated seasonal variability of crop hail losses did not change significantly due to the enhanced greenhouse effect. These results depended on two important assumptions. Firstly| it was assumed that the dominant relationships between climatic variables and crop hail losses in the past would remain the same in a future climate. Secondly| it was assumed that the single mixed-layer GCMs used in the study were correctly predicting climate change under enhanced greenhouse conditions. 5086,1999,2,4,The relationship between near-surface air temperature over land and the annual amplitude of the atmosphere's seasonal CO2 cycle,The seasonal growth and decay of Northern Hemispheric terrestrial vegetation creates a seasonal oscillation in the atmospheric CO2 concentration in the Northern Hemisphere. Over the past several decades| the amplitude of this seasonal cycle has risen substantially. Many potential causes of this phenomenon have been suggested; but the one that seems currently to be of most concern is global warming. This study thus seeks to determine if the rise in the near-surface air temperature of the past 35 years has been the major factor in driving the contemporaneous increase in the amplitude of the Northern Hemisphere's seasonal CO2 cycle. Annual CO2 amplitude data from ten Northern Hemispheric stations of the NOAA/CMDL continuous monitoring network were regressed against mean near-surface air temperatures over land areas located within each 5 degrees latitude band stretching from the equator to 85 degrees N. Temperature effects were non-existent when the CO2 amplitude and temperature data were contemporaneous| whereas they were maximal when the CO2 amplitude data lagged the temperature data by 2 years| declining slowly thereafter to become non-existent again between a lag time of 6-7 years. For the peak-impact 2-year lag situation| low-latitude temperatures were much more strongly correlated with the CO2 amplitude data than were mid- or high-latitude temperatures. The 2-year-lag results for Mauna Loa and Point Barrow indicate that Northern Hemispheric warming may have been responsible for about a fifth of the annual CO2 amplitude increase observed at Mauna Loa from 1960 to 1995 and approximately a tenth of the amplitude increase recorded at Point Barrow over this period. Consequently| the majority of the Northern Hemispheric CO2 amplitude increase appears to be due to the influence of some other factor or combination of factors| a number of which have been suggested in the literature. (C) 1999 Elsevier Science B.V. All rights reserved.
4912,1999,3,4,The role of international environmental agreements in metered dose inhaler technology changes,Introduced in the 1950s| metered dose inhalers (MDIs) became a revolutionary way to deliver medication directly to the lungs of patients with asthma and chronic obstructive pulmonary disease. Since their initial introduction| MDIs have used chlorofluorocarbons to propel the medication out of the canister into a patient's lungs. This article presents an overview of the global transition away from the use of chlorofluorocarbon propellants in MDIs to non-ozone-depleting substitutes including hydrofluoroalkane (outside of the pharmaceutical industry and in the context of Montreal Protocol and Kyoto Protocol discussions| these gases are referred to as hydrofluorocarbons; hydrofluoroalkane-134a| for example| is referred to as hydrofluorocarbon-134a) propellants| in accordance with the terms of the international environmental agreement the Montreal Protocol on substances that deplete the ozone layer (the Montreal Protocol). This article will also describe the environmental characteristics of chlorofluorocarbons and hydrofluoroalkanes when they are used as MDI propellants. Finally| the article will review key provisions of the pending Kyoto Protocol to the United Nations Framework Convention on Climate Change (the Kyoto Protocol) that may affect the future of hydrofluoroalkanes. 2229,1999,3,4,The role of landfills in the United Kingdom,The paper describes the priority given to licensing in the control of waste management in the UK. It outlines both the historical and present day impact of EU legislation on UK practices and explains potential problems and benefits resulting from the implementation of the EU landfill directive. Basic waste data is given and some of the key factors underpinning waste regulation are delineated primarily sustainable development - but also land-use planning| groundwater protection and global climate change. The paper concludes by profiling the UK's lifecycle programme for waste management and its intended uses. 4940,1999,3,3,The role of methane in global warming: where might mitigation strategies be focused?,Anthropogenic sources of methane emissions are thought to be nearly twice as high as emissions from natural sources. As the second most important anthropogenic greenhouse gas after carbon dioxide| methane ought to be addressed by policy makers when they consider reductions of national greenhouse-gas inventories. This article first comprehensively reviews source and sink estimates of methane by natural and anthropogenic sectors (wetlands| wet-paddy rice farming| livestock farming| biomass burning| landfills| coal mining| and venting of natural gas or natural-gas pipeline leaks)| then proceeds to suggest where different mitigation strategies might be applied. The final section considers how the scenario of a warmer planet may affect the methane biogeochemical cycle. (C) 1999 Elsevier Science Ltd. All rights reserved. 2232,1999,2,3,The role of physical processes in determining the interdecadal variability of central Arctic sea ice,The importance of the Arctic region for global climate change has recently been highlighted in the results from general circulation model simulations under increasing atmospheric CO| scenarios. The warming that is predicted by these studies is most pronounced in the polar regions| indicating that it may be the first place in which the effects of global climate change will be detected. However| the natural variability that is present in the Arctic climate system is largely unknown and is likely to obscure the detection of anthropogenically forced changes. Additionally| there is little information on the internal processes of the Arctic ice pack| which are important for determining the variability of the ice cover. In an effort to address these issues| the variability of the Arctic ice volume is examined using a single column sea ice-ocean mixed layer model. The model contains an ice thickness distribution and the parameterization of export and ridging due to ice divergence and shear. Variability in the ice cover is forced by applying stochastic perturbations to the air temperature and ice divergence forcing fields. Several sensitivity tests are performed in order to assess the role of different physical processes in determining the variability of the perennial Arctic ice pack. It is found that the surface albedo and ice-ocean feedback mechanisms act to enhance the variability of the ice volume and are particularly important for the simulated response of the sea ice to fluctuations in air temperature| accounting for approximately 62% and 25% of the ice volume variance| respectively. The details of the ice thickness distribution also significantly affect the simulated variability. In particular| the ridging process acts to decrease the simulated variability of the ice pack. It reduces the variance of the ice volume by 50% when air temperature stochastic forcing is applied. 4994,1999,4,3,The role of water vapor feedback in unperturbed climate variability and global warming,To understand the role of water vapor feedback in unperturbed surface temperature variability| a version of the Geophysical Fluid Dynamics Laboratory coupled ocean-atmosphere model is integrated for 1000 yr in two configurations| one with water vapor feedback and one without. For all spatial scales| the model with water vapor feedback has more low-frequency (timescale greater than or equal to 2 yr) surface temperature variability than the one without. Thus water vapor feedback is positive in the context of the model's unperturbed variability. In addition| water vapor feedback is more effective the longer the timescale of the surface temperature anomaly and the larger its spatial scale. To understand the role of water vapor feedback in global warming| two 500-yr integrations were also performed in which CO2 was doubled in bath model configurations. The final surface global warming in the model with water vapor feedback is 3.38 degrees C| while in the one without it is only 1.05 degrees C. However| the model's water vapor feedback has a larger impact on surface warming in response to a doubling of CO2 than it does on internally generated| low-frequency| global-mean surface temperature anomalies. Water vapor feedback's strength therefore depends on the type of temperature anomaly it affects. The authors found that the degree to which a surface temperature anomaly penetrates into the troposphere is a critical factor in determining the effectiveness of its associated water vapor feedback. The more the anomaly penetrates| the stronger the feedback. It is also shown that the apparent impact of water vapor feedback is altered by other feedback mechanisms| such as albedo and cloud feedback. The sensitivity of the results to this fact is examined. Finally| the authors compare the local and global-mean surface temperature time series from both unperturbed variability experiments to the observed record. The experiment without water vapor feedback does not have enough global-scale variability to reproduce the magnitude of the variability in the observed global-mean record| whether or not one removes the warming trend observed over the past century. In contrast| the amount of variability in the experiment with water vapor feedback is comparable to that of the global mean record| provided the observed warming trend is removed. Thus| the authors are unable to simulate the observed levels of variability without water vapor feedback. 5128,1999,4,2,The Southern Ocean response to global warming in the CSIRO coupled ocean-atmosphere model,The Southern Ocean response to global warming is examined for a transient greenhouse gas integration using the Commonwealth Scientific and Industrial Research Organisation (CSIRO) coupled ocean-atmosphere model. The ocean component includes the Gent and McWilliams scheme for adiabatic eddy-induced transport. The atmospheric equivalent CO2 concentration (CO2e) follows the IPCC/IS92a radiative forcing scenario from 1880 to 2082| and is then maintained at a constant value of three times the 1880 level for seven centuries. The simulated changes which occur in the Southern Ocean under global warming are very profound| and they begin to separate clearly from the background climate noise in the model's 1990s. A major reduction in the depth and extent of convective mixing occurs by the time of CO2e doubling (year 2033)| with near-cessation of convection by the time of CO2e tripling. Similarly major reduction occurs in the downwelling adjacent to Antarctica associated with Antarctic Bottom Water formation| which also nearly ceases by the time of CO2e tripling. These changes are associated with a marked reduction in surface density and salinity. By the time of CO2e tripling| both the pycnocline and halocline south from 60 degrees S intensify over the control by about a factor of four. The changes in surface salinity and density continue to intensify for several centuries during the subsequent period of elevated stable CO2e| and convection and Antarctic downwelling do not recover at all for the duration of the transient run. The water of the entire global ocean below about 1.5 km depth remains stagnant for the duration of the period of elevated stable CO2e| retaining a density which is too great to allow renewal from any source. Possible caveats on the realism of these results are discussed| and potential consequences of the above changes are noted. (C) 1999 Elsevier Science Ltd. All rights reserved. 5061,1999,2,2,The stability of the thermohaline circulation in global warming experiments,A simplified climate model of the coupled ocean-atmosphere system is used to perform extensive sensitivity studies concerning possible future climate change induced by anthropogenic greenhouse gas emissions. Supplemented with an active atmospheric hydrological cycle| experiments with different rates of CO2 increase and different climate sensitivities are performed. The model exhibits a threshold value of atmospheric CO2 concentration beyond which the North Atlantic Deep Water formation stops and never recovers. For a climate sensitivity that leads to an equilibrium warming of 3.6 degrees C for a doubling of CO2 and a rate of CO2 increase of 1% yr(-1)| the threshold lies between 650 and 700 ppmv. Moreover| it is shown that the stability of the thermohaline circulation depends on the rate of increase of greenhouse gases. For a slower increase of atmospheric pCO(2) the final amount that can be reached without a shutdown of the circulation is considerably higher. This rate-sensitive response is due to the uptake of heat and excess freshwater from the uppermost layers to the deep ocean. The increased equator-to-pole freshwater transport in a warmer atmosphere is mainly responsible for the cessation of deep water formation in the North Atlantic. Another consequence of the enhanced latent heat transport is a stronger warming at high latitudes. A model version with fixed water vapor transport exhibits uniform warming at all latitudes. The inclusion of a simple parameterization of the ice-albedo feedback increases the model sensitivity and further decreases the pole-to-equator temperature difference in a greenhouse climate. The possible range of CO2 threshold concentrations and its dependency on the rate of CO2 increase| on the climate sensitivity| and on other model parameters are discussed. 4976,1999,2,4,The structural changes in bacterial communities of soddy gleysols caused by their drying,The structural changes in bacterial communities were investigated in the model experiment on the gradual decrease in moisture content for a soddy gleysol from the Central Forest State Biosphere Reserve under two different regimes. The slow drying in the desiccator caused a smooth decrease in bacterial population and diversity. Soil drying increased the relative generic abundance of actinobacteria and bacilli. The transformations identified in bacterial communities are expected to occur under natural conditions in the case of possible global warming. 4973,1999,3,3,The substitution of high-resolution terrestrial biosphere models and carbon sequestration in response to changing CO2 and climate,Strategies are developed to analyze and represent spatially resolved biosphere models for carbon sequestration in response to changes in atmospheric CO2 and climate by reduced-form| substitute models. We explore the High-Resolution Terrestrial Biosphere Model as implemented in the Community Terrestrial Biosphere Model (HRBM/CTBM)| the Frankfurt Biosphere Model (FBM)| and the box-type biosphere of the Bern model. Storage by CO2 fertilization is described by combining analytical representations of (1) net primary productivity (NPP) as a function of atmospheric CO2 and (2) a decay impulse response function to characterize the timescales of biospheric carbon turnover. Storage in response to global warming is investigated for the HRBM/CTBM. The relation between the evolution of radiative forcing and climate change is expressed by a combination of impulse response functions and empirical orthogonal functions extracted from results of the European Center/Hamburg (ECHAM3) coupled atmosphere-ocean general circulation model. A box-type| differential-analogue substitute model is developed to represent global carbon storage of the HRBM/CTBM in response to regional changes in Temperature| Precipitation and cloud cover. The substitute models represent the spatially resolved models accurately and cost-efficiently for carbon sequestration in response to changes in CO2 or in CO2 and climate and for simulations of the global isotopic signals. Deviations in carbon uptake simulated by the spatially resolved models and their substitutes are less than a few percent. 5022,1999,3,3,Toward marginal cost pricing of accident risk: the energy| travel| and welfare impacts of pay-at-the-pump auto insurance,This paper examines| theoretically and through a series of simulations| the effect of a pay-at-the-pump auto insurance system where the minimum amount of insurance required by California law is paid through a fuel surcharge. Vehicle fixed costs are reduced while variable costs increase. The results show that gasoline demand would be reduced by roughly two to five percent in 1998 (with greater percentage drops in later years)| while VMT would drop by slightly less as the incentive to drive more fuel efficient vehicles reduces exposure to the tax. At the same time| pay-at-the-pump is shown to improve the welfare of the average California driver as insurance is priced more efficiently. In other words| unlike other transportation pricing measures that have been proposed in the recent past (VMT and fuel taxes| pollution fees| etc.)| PATP may offer a means of reducing the external costs of transportation (global warming| congestion| etc.) without raising private costs for the average motorist. Another appealing aspect of PATP may be its apparently progressive nature-the lowest income households may see the highest gains in welfare. (C) 1999 Elsevier Science Ltd. All rights reserved. 5107,1999,2,3,Transferring soils from high- to low-elevation forests increases nitrogen cycling rates: climate change implications,We assessed the potential impact of global warming resulting from a doubling of preindustrial atmospheric CO2 on soil net N transformations by transferring intact soil cores (0-15 cm) from a high-elevation old-growth forest to a forest about 800 m lower in elevation in the central Oregon Cascade Mountains| USA. The lower elevation site had mean annual air and soil (10-cm mineral soil depth) temperatures about 2.4 and 3.9 degrees C higher than the high-elevation site| respectively. Annual rates of soil net N mineralization and nitrification more than doubled in soil transferred to the low-elevation site (17.2-36.0 kg N ha(-1) and 5.0-10.7 kg NO3--N ha(-1)| respectively). Leaching of inorganic N from the surface soil tin the absence of plant uptake) also increased. The reciprocal treatment (transferring soil cores from the low- to the high-elevation site) resulted in decreases of about 70| 80| and 65% in annual rates of net N mineralization| nitrification| and inorganic N leaching| respectively. Laboratory incubations of soils under conditions of similar temperature and soil water potential suggest that the quality of soil organic matter is higher at the high-elevation site. Similar in situ rates of soil net N transformations between the two sites occurred because the lower temperature counteracts the effects of greater substrate quantity and quality at the high elevation site. Our results support the hypothesis that high-elevation| old-growth forest soils in the central Cascades have higher C and N storage than their low-elevation analogues primarily because low temperatures limit net C and N mineralization rates at higher elevations. 5092,1999,2,4,Understanding and prediction of soil microbial community dynamics under global change,The review deals with quantitative descriptions of soil microbial processes in northern terrestrial ecosystems and predictions of their possible modifications under anticipated global changes. The main focus is the dependence of population dynamics of soil microorganisms on environmental factors. To simulate microbial dynamics| mechanistic mathematical models are suggested which summarize the contemporary information on physiology and molecular biology of organisms representing different life strategies. The major independent environmental factors were clustered into three main groups: (i) soil mineral resources (available and deposited biogenic elements); (ii) factors related to solar radiation (sunlight| clouds| temperature| active layer| UVB); and (iii) factors affecting gas and liquid mass transfer (soil texture and porosity| vascular transfer| water regime). The quality and amount of organic matter which provide the sources of C and energy for most soil microorganisms are considered as dependent variables and can be generated by simulation models as a product of biosynthetic activity of plants and microorganisms. A strong interaction between different factors has been demonstrated| e.g. temperature and amount of available C nutrients which can be explained in physiological terms. The simulation of the tundra microbial community revealed its relatively high stability to global warming. Elevated temperatures and input of dead organic matter relieved the pressure of L-selection and accelerated an aerobic decomposition of dead organic matter (plant litter| soil humus). (C) 1999 Elsevier Science B.V. 5017,1999,3,2,Using science to advocate action on climate change,Climate change is probably the greatest threat to global ecosystems that humanity has ever faced. Greenhouse gases| primarily from the production and combustion of fossil fuels for human energy needs| are heating up our atmosphere| changing our climate| and threatening the health and well-being of people the world over. Pre dieted consequences of climate change include more frequent extreme weather events such as intensive precipitation| drought and floods| rising sea levels| increased smog in cities| and the possible spread of tropical diseases to more temperate dimes. These grim effects can be limited if societies throughout the world act quickly to reduce greenhouse gas emissions. Substantially reducing emissions| however| means a fundamental shift in the way we produce and consume energy. To help bring about change| scientists| health professionals and nongovernment organizations such as the David Suzuki Foundation must work together to educate and motivate the public| industries| business organizations| and governments to take actions that will reduce the threat of global warming. 2238,1999,5,4,Variability in Late Cretaceous climate and deep waters: evidence from stable isotopes,Strong climatic and temperature fluctuations mark the Late Campanian and Maastrichtian as indicated by stable isotope records from the equatorial Pacific (Site 463) and middle and high latitude South Atlantic (Sites 525| 689 and 690). The first major global cooling decreased intermediate water temperatures (IWT) by 5-6 degrees C between 73-70 Ma. At the same time| sea surface temperature (SST) decreased by 4-5 degrees C in middle and high latitudes. Intermediate waters (TW) temporarily warmed by 2 degrees C in low and middle latitudes between 70-68.5 Ma. Global cooling resumed between 68.5-65.5 Ma when IWT decreased by 3-4 degrees C and SST by 5 degrees C in middle latitudes. About 450 ka before the Cretaceous-Tertiary boundary rapid global warming increased IWT and SST by 3-4 degrees C| though SST in the tropics changed little. During the last 200 ka of the Maastrichtian| climate cooled rapidly with IWT and SST decreasing by 2-3 degrees C. During the global cooling at 71-70 Ma and possibly at 67-65.5 Ma| the sources of cold intermediate waters in the equatorial Pacific| Indo-Pacific and South Atlantic were derived from the high latitude North Pacific. In contrast| during the global climate warming between 65.2-65.4 Ma| the middle latitude South Atlantic was closest to the source of IW production and implies that the low latitude Tethys played a major role in global climate change. Climate changes| sea-level fluctuations and associated restricted seaways appear to be the most likely mechanisms for the alternating sources of IW production. (C) 1999 Elsevier Science B.V. All rights reserved. 4975,1999,3,4,Vegetable oils for biofuels versus surfactants: an ecological comparison for energy and greenhouse gases,This paper compares the use of vegetable oils as energy carriers on the one hand and for the production of chemicals on the other hand. The bio-based energy carriers analyzed are rapeseed oil| rapeseed oil methyl ester| and palm oil methyl ester| all of which can be used as substitutes for diesel fuel. The chemicals studied are surfactants. Surfactants can be produced from plant-based feedstocks (oleochemical surfactants) and from petrochemicals. The various options are studied with regard to two ecological indicators| i.e. the consumption of finite energy resources and the global warming potential. First of all| for these two aspects plant-based sources show clear advantages when compared with their fossil counterparts. Secondly| the transesterified types of biofuels are more advantageous than pure vegetable oils. Thirdly| the conservation of finite energy and reduction in emissions of greenhouse gases are higher if vegetable oils are used as a feedstock to produce oleochemical surfactants compared to their use as biofuels. Comprehensive lift-cycle analyses must be carried our in order to determine whether these results can also be applied to other ecological indicators. The results presented in this paper support developing strategic goals for bio-based feedstocks| including quantity and cost targets. 5103,1999,4,3,Volatile anaesthetics and the atmosphere: atmospheric lifetimes and atmospheric effects of halothane| enflurane| isoflurane| desflurane and sevoflurane,The atmospheric lifetimes of the halogenated anaesthetics halothane| enflurane| isoflurane| desflurane and sevoflurane with respect to reaction with the hydroxyl radical (OH) and UV photolysis have been determined from observations of OH reaction kinetics and UV absorption spectra. Rate coefficients for the reaction with OH radicals for all halogenated anaesthetics investigated ranged from 0.44 to 2.7 x 10(-14) cm(3) molec(-1) s(-1). Halothane| enflurane and isoflurane showed distinct UV absorption in the range 200-350 nm. In contrast| no absorption in this wavelength range was detected for desflurane or sevoflurane. The total atmospheric lifetimes| as derived from both OH reactivity and photolysis| were 4.0-21.4 yr. it has been calculated that up to 20% of anaesthetics enter the stratosphere. As a result of chlorine and bromine content| the ozone depletion potential (ODP) relative to chlorofluorocarbon CFC-11 varies between 0 and 1.56| leading to a contribution to the total ozone depletion in the stratosphere of approximately 1% for halothane and 0.02% for enflurane and isoflurane. Estimates of the greenhouse warming potential (GWP) relative to CFC-12 yield values of 0.02-0.14| resulting in a relative contribution to global warming of all volatile anaesthetics of approximately 0.03%. The stratospheric impact of halothane| isoflurane and enflurane and their influence on ozone depletion is of increasing importance because of decreasing chlorofluorocarbons globally. However| the influence of volatile anaesthetics on greenhouse warming is small. 4926,1999,2,3,Water resources implications of global warming: A US regional perspective,The implications of global warming for the performance of six U.S. water resource systems are evaluated. The six case study sites represent a range of geographic and hydrologic| as well as institutional and social settings. Large| multi-reservoir systems (Columbia River| Missouri River| Apalachicola-Chatahoochee-Flint (ACF) Rivers)| small| one or two reservoir systems (Tacoma and Boston) and medium size systems (Savannah River) are represented. The river basins range from mountainous to low relief and semi-humid to semi-arid| and the system operational purposes range from predominantly municipal to broadly multi-purpose. The studies inferred| using a chain of climate downscaling| hydrologic and water resources systems models| the sensitivity of six water resources systems to changes in precipitation| temperature and solar radiation. The climate change scenarios used in this study are based on results from transient climate change experiments performed with coupled ocean-atmosphere General Circulation Models (GCMs) for the 1995 Intergovernmental Panel on Climate Change (IPCC) assessment. An earlier doubled-CO2 scenario from one of the GCMs was also used in the evaluation. The GCM scenarios were transferred to the local level using a simple downscaling approach that scales local weather variables by fixed monthly ratios (for precipitation) and fixed monthly shifts (for temperature). For those river basins where snow plays an important role in the current climate hydrology (Tacoma| Columbia| Missouri and| to a lesser extent| Boston) changes in temperature result in important changes in seasonal streamflow hydrographs. In these systems| spring snowmelt peaks are reduced and winter flows increase| on average. Changes in precipitation are generally reflected in the annual total runoff volumes more than in the seasonal shape of the hydrographs. In the Savannah and ACF systems| where snow plays a minor hydrological role| changes in hydrological response are linked more directly to temperature and precipitation changes. Effects on system performance varied from system to system| from GCM to GCM| and for each system operating objective (such as hydropower production| municipal and industrial supply| flood control| recreation| navigation and instream flow protection). Effects were generally smaller for the transient scenarios than for the doubled CO2 scenario. In terms of streamflow| one of the transient scenarios tended to have increases at most sites| while another tended to have decreases at most sites. The third showed no general consistency over the six sites. Generally| the water resource system performance effects were determined by the hydrologic changes and the amount of buffering provided by the system's storage capacity. The effects of demand growth and other plausible future operational considerations were evaluated as well. For most sites| the effects of these non-climatic effects on future system performance would about equal or exceed the effects of climate change over system planning horizons. 4915,1999,2,4,Weather and climate extremes| climate change| and planning - Views of community water system managers in Pennsylvania's Susquehanna River Basin,This research examines the sensitivity and vulnerability of community water systems (CWSs) to weather and climate in the Pennsylvania portion of the Susquehanna River Basin. Three key findings emerge from a survey of 506 CWS managers. First| CWSs are sensitive to extreme weather and climate| but that sensitivity is determined more by type of system than system size. CWSs that rely partly or wholly on surface water face more disruptions than do groundwater systems. Larger systems have more problems with flooding| and size is not a significant determinant of outages from storms or disruptions from droughts. Second| CWS managers are unsure about global warming. Few managers dismiss global warming; most think global warming could be a problem but are unwilling to consider it in their planning activities until greater scientific certainty exists. Third| the nature of the CWS| its sensitivity to weather and climate| and projected risks from weather and climate are insignificant determinants of how managers plan. Experienced| full-time managers are more likely to consider future weather and climate scenarios in their planning| while inexperienced and part-time managers are less likely to do so. Implications of these findings include support for efforts to move away from surface water| for clear communication of climate change information| and for the hiring and retention of full-time professional CWS managers. 4905,1999,2,3,Weeds| insects| and diseases,The geographic distribution| vigor| virulence| and agricultural impact of weeds| insects| and plant pathogens will be affected by climatic changes accompanying the global "greenhouse effect." Weed/crop competitive interactions| particularly among species differing in photosynthetic pathway (C(3) v C(4))| may be altered| with the C(3) species favored by increasing CO(2). Physiological and biochemical changes induced in host crop plants by rising CO(2) may affect feeding patterns of pest insects. Compilation of climatic thresholds for phenological development of pest insects reveals the potential for shifts in pest behavior induced by global warming and other climatic change. Generation times may be reduced| enabling more rapid population increases to occur. Poleward migration may be accelerated during the crop season. The epidemiology of plant diseases also will be altered. Prediction of disease outbreaks will be more difficult in periods of rapidly changing climate and unstable weather. Environmental instability and increased incidence of extreme weather may reduce the effectiveness of pesticides on targeted pests or result in more injury to non-target organisms. Biological control may be affected either negatively or positively. Overall| the challenge to agriculture from pests probably will increase. 4901,1999,2,4,Wetter isn't better: global warming and food security in the Congo Basin,Over 20 million forest farmers practice slash and burn agriculture in the forests of the Congo Basin (Bahuchet and de Maret| 1995. State of Indigenous Populations Living in Rainforest Areas| European Commission DG XI Environment| Brussels). They rely on the long dry season (December-February north of the equator) to ensure that their new fields| cleared from regrowth forest| burn sufficiently well to deposit nutrients into the soil and to minimize the labor required to prepare the field for planting. Data from the Ituri forest in northeastern Democratic Republic of Congo show that the strength of the annual dry season (a) has a direct positive impact on the size of fields cleared each year by slash and burn farmers| and consequently on food production and the severity of the subsequent year's pre-harvest hunger period; and (b) is inversely related to total annual rainfall. These results suggest that the 1 mm/d increase in rainfall predicted for much of the Congo Basin by the 2050s may cause a basin wide increase in the frequency of heavy rains during the dry season| causing a reduction in the size of slash and burn farmers' fields| and potentially a substantial increase in the food insecurity of poor rural families across the region. (C) 1999 Elsevier Science Ltd. All rights reserved. 2241,1999,4,4,What shall we do with the data we are expecting from upcoming earth observation satellites?,The community of researchers studying global climate change is preparing to launch the first Earth observing system (EOS) satellite| EOS Terra. The satellite will generate huge amounts of data| filling gaps in the information available to address critical questions about Earth's climate. But many data handling and data analysis problems must be solved if we are to make best use of the new measurements. In key areas| the experience and expertise of the statistics community could be of great help. 5080,1999,4,4,Why is the global warming proceeding much slower than expected?,Upper air observations from radiosondes and microwave satellite instruments does not indicate any global warming during the last 19 years| contrary to surface measurements| where a warming trend is supposedly being found. This result is somewhat difficult to reconcile| since climate model experiments do indicate a reverse trend| namely| that upper tropospheric air should warm faster than the surface. To contribute toward an understanding of this difficulty| we have here undertaken some specific experiments to study the effect on climate due to the decrease in stratospheric ozone and the Mount Pinatubo eruption in 1991. The associated forcing was added to the forcing from greenhouse gases| sulfate aerosols (direct and indirect effect)| and tropospheric ozone| which was investigated in a separate series of experiments. Furthermore| we have undertaken an ensemble study in order to explore the natural variability of an advanced climate model exposed to such a forcing over 19 years. The result shows that the reduction of stratospheric ozone cools not only the lower stratosphere but also the troposphere| in particular| the upper and middle part. In the upper troposphere the cooling from stratospheric ozone leads to a significant reduction of greenhouse warming. The modeled stratospheric aerosols from Mount Pinatubo generate a climate response (stratospheric warming and tropospheric cooling) in good agreement with microwave satellite measurements. Finally| analysis of a series of experiments with both stratospheric ozone and the Mount Pinatubo effect shows considerable variability in climate response| suggesting that an evolution having no warming in the period is as likely as another evolution showing modest warming. However| the observed trend of no warming in the midtroposphere and clear warming at the surface is not found in the mode! simulations. 5065,1999,3,4,World population and energy demand growth: the potential role of fusion energy in an efficient world,The fertility rate for women and the related population growth rate for numerous developing (transitional) countries show a downward trend with increasing annual per capita energy use. On the assumption that such trends will continue| estimates are made for some simple cases of the energy demands required to stabilize the world's population in the period 2100-2150. An assessment is made of how these energy demands might be met| capitalizing as much as possible on the indigenous energy resources for each of the ten major regions of the world: North America| Latin America| Europe OECD| Former Soviet Union and Central and Eastern Europe| China| Pacific OECD| East Asia| South Asia| Africa| and the Middle East. Consideration is also given to the potential need to limit carbon emissions because of global-warming concerns. The study highlights the crucial nature of energy-efficiency improvements and the need to use all energy sources if the world is to find a sustainable future with a much improved standard of living in the developing world. While| globally| there are huge resources of fossil fuels| they are unevenly distributed and some of the areas experiencing major population growth are not well endowed with them. Even allowing for the substantial deployment of renewable energies (biomass| geothermal| hydro-|tide| wave and wind power)| if fossil-fuel use is restricted or has limited availability| there will be a need in a number of regions (e.g. South Asia) for substantial amounts of nuclear and solar energy to meet their long-term needs. The deployment of more fission power can build upon the existing successes. The availability of fusion power will depend upon the pace of the development program and| in principle| fusion-power deployment might start around the middle of the 21st century. Example scenarios of possible contributions of the various energy sources are described| to illustrate the potential roles for fission and fusion power. 5294,2000,3,4,A co-evolutionary approach to climate change impact assessment: Part I. Integrating socio-economic and climate change scenarios,Climate change policies currently pay disproportionately greater attention to the mitigation of climate change through emission reductions strategies than to adaptation measures. Realising that the world is already committed to some global warming| policy makers are beginning to turn their attention to the challenge of preparing society to adapt to the unfolding impacts at the local level. This two-part article presents an integrated| or 'co-evolutionary'| approach to using scenarios in adaptation and vulnerability assessment. Part I explains how climate and social scenarios can be integrated to better understand the inter-relationships between a changing climate and the dynamic evolution of social| economic and political systems. The integrated scenarios are then calibrated so that they can be applied 'bottom up' to local stakeholders in vulnerable sectors of the economy. Part I concludes that a co-evolutionary approach (1) produces a more sophisticated and dynamic account of the potential feedbacks between natural and human systems; (2) suggests that sustainability indicators are both a potentially valuable input to and an output of integrated scenario formulation and application. Part II describes how a broadly representative sample of public| private and voluntary organisations in the East Anglian region of the UK responded to the scenarios| and identifies future research priorities. (C) 2000 Elsevier Science Ltd. All rights reserved. 5302,2000,2,4,A comparative analysis of the upper thermal tolerance limits of eastern Pacific porcelain crabs| genus Petrolisthes: Influences of latitude| vertical zonation| acclimation| and phylogeny,Marine intertidal organisms are subjected to a variety of abiotic stresses| including aerial exposure and wide ranges of temperature. Intertidal species generally have higher thermal tolerance limits than do subtidal species| and tropical species have higher thermal tolerance limits than do temperate species. The adaptive significance of upper thermal tolerance limits of intertidal organisms| however| has not been examined within a compar- ative context. Here| we present a comparative analysis of the adaptive significance of upper thermal tolerance limits in 20 congeneric species of porcelain crabs| genus Petrolisthes| from intertidal and subtidal habitats throughout the eastern Pacific. Upper thermal tolerance limits are positively correlated with surface water temperatures and with maximal microhabitat temperatures. Analysis of phylogenetically independent contrasts (from a phylogenetic tree on the basis of the 16s rDNA gene sequence) suggests that upper thermal tolerance limits have evolved in response to maximal microhabitat temperatures. Upper thermal tolerance limits increased during thermal acclimation at elevated temperatures| the amount of increase being greater for subtidal than for intertidal species. This result suggests that the upper thermal tolerance limits of some intertidal species may be near current habitat temperature maxima| and global warming thus may affect the distribution limits of intertidal species to a greater extent than for subtidal species. 5350,2000,2,4,A geometric glacier model for sea-level change calculations,Towards accounting for the dynamic response of glaciers and ice caps in the estimation of their contribution to sea-level rise due to global warming| a mass-balance degree-day model is coupled to a geometric glacier model. The ice dynamics are treated implicitly in the geometric model by using scaling parameters that have been extensively investigated in the literature. The model is tested by presenting a case-study of the glacier Hintereisferner| Austrian Alps. The results are compatible with geomorphological data and other modelling studies. An estimate is made of the volume decrease due to initial disequilibrium. An extensive sensitivity study using generalized glacier shapes and sizes allows a comparison of results with dynamic theory. According to the geometric model| glaciers with a narrowing channel change more with a change in mass balance than glaciers with a widening channel| due to their shape and the way in which that shape changes with a changing climate. Also their response ti:me is longer. As time progresses after a mass-balance perturbation| the longer response time for continental glaciers compared to glaciers with larger mass turnover offsets the effect of their smaller static sensitivity. Thus| although for the next century we may expect greater changes in volume from alpine glaciers| the equilibrium or committed change is greater for the continental glaciers. 5237,2000,5,4,A giant vampire (Mammalia| Chiroptera) in the Late Holocene from the Argentinean pampas: paleoenvironmental significance,The first fossil desmodontine record and the only well documented chiropteran fossil record from Argentina is described. A complete left upper canine was collected at Centinela del Mar (38 degrees 21'S58 degrees W| General Alvarado County| Buenos Aires Province) from fossil-bearing sediments referred to the Late Holocene. The tooth size is 25% larger than that of the modern vampire bat. Desmodus rotundus. We assign this tooth to Desmodus cf. D. draculae| an extinct species recorded in the Pleistocene-Holocene of South America (Brazil and Venezuela). The southernmost distribution of present-day Desmodus extends to northeast Buenos Aires province (35 degrees S). The presence of Desmodus some 600 km south of this present-day limit (July minimal isotherm of 10 degrees C) indicates that around 300 years BP the southeastern Buenos Aires province was at least 2 degrees C higher than modern July isotherm. The Desmodus tooth is associated with sigmodontine rodents characteristic of subtropical and temperate-warm areas (e.g.| Pseudoryzomys simplex| Bibimys cf. B. torresi)| and provides additional evidence to support this hypothesis. A correlation with a global warming phase is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. 5206,2000,2,4,A model analysis of the relationship between climate perturbations and carbon budget anomalies in global terrestrial ecosystems: 1970 to 1997,We performed a model analysis of the effect of climatic perturbations from 1970 to 1997 on the carbon budget of terrestrial ecosystems at the global scale. The model| Sim-CYCLE| enabled us to simulate carbon storage in terrestrial pools and monthly carbon fluxes between the atmosphere and the biosphere| e.g| photosynthesis| respiration| decomposition| and net ecosystem production (NEP). For the global analysis| we adopted the Matthews biome distribution map (12 biome types) and the US National Centers for Environmental Prediction and the US National Center for Atmospheric Research (NCEP/NCAR) reanalysis climate dataset| which is at a spatial resolution of T62 (5828 land cells). During the 28 yr experimental period| global NEP showed considerable climate-induced interannual anomalies (Delta NEPs) ranging from -2.06 Pg C yr(-1) (source) in 1983 to +2.25 (sink) Pg C yr(-1) in 1971| being sufficiently large to give rise to anomalies in the atmospheric CO(2) concentration from +0.97 to -1.06 ppmv. Regression analyses demonstrated the following: (1) annual Delta NEPs had the highest correlation (r(2) = 0.38) with the temperature anomaly at the global scale; (2) the anomalies in precipitation resulted in a considerable Delta NEP in northern high and middle regions; (3) an anomalous global warming by +1 degreesC brought about a negative Delta NEP of -2.7 Pg C yr(-1); (4) the responsiveness was primarily attributable to the temperature sensitivities of plant respiration and: soil decomposition| and secondarily to the moisture sensitivity of decomposition; and (5) the temperature dependence of Delta NEP had a clear seasonality| i.e. most sensitive in July to September (summer in the northern hemisphere) relative to other seasons. In 1983| when an ENSO event happened and the tropical zone was anomalously hot (0.4 degreesC above the longterm mean)| the largest negative Delta NEP (-2.06 Pg C yl-l) was estimated. On the other hand| in 1971| when global mean temperature was relatively low (0.2 degreesC below the long-term mean)| the largest positive Delta NEP (+2.25 Pg C y(-1)) was estimated. Furthermore| in 1992| when an anomalous cooling during the growing period (0.3 degreesC below the long-term mean) was caused by the Mt. Pinatubo eruption (June 1991)| a considerable positive Delta NEP (+1.14 Pg C yr(-1)) was estimated. The climate dependencies of global terrestrial ecosystems analyzed here may contain significant implications not only for the present functioning of atmosphere-biosphere carbon exchange| but also for ongoing global warming. 5229,2000,2,4,A modelling analysis of the genetic variation of phenology between tree populations,1 The phenology of temperate woody plants is commonly assumed to be locally adapted to climate. 2 However| the high gene flow expected in forest tree species| the high between year variance of thermal conditions at a given place and the high plasticity of phenology regarding temperature| lead us to hypothesize that genetic variation of phenology between populations is likely to be insignificant for many lowland tree species. 3 Using phenological models| we investigated variation in the timing of flowering between locations for four European clonal tries and between different populations of a further five species. 4 Models were also used to study the responses of the different populations to climate change by simulating transfers of each population to different locations. 5 While clinal variations can be observed in the phenological response to temperature between populations| only one species (Corylus avellana) showed significantly different responses between populations and even then only one of three populations could be separated from the others. 6 Hypothetical transfers show that the differences observed between populations depend on the thermal conditions at the location of transfer| and that these differences are less marked in warmer conditions. 7 Our results indicate that local adaptation will probably not be a serious constraint in predicting the phenological responses of temperate lowland tree species to global warming. 5244,2000,4,4,A monthly stream flow model for estimating the potential changes of river runoff on the projected global warming,Hydrological processes in high altitude mountainous regions differ from those in more temperate regions| primarily due to such influences as cold temperatures| large and rapid change in surface energy balance during snowmelt| a long period at low-temperature environmental condition and the existence of permafrost. A physically based| semi-distributed water balance model to quantitatively simulate the hydrological processes and stream flow| as well as to estimate the potential consequences of projected global warming on stream Row for such high altitude mountainous regions was constructed. Distributed meteorological data from the interpolation of the point measurements by means of a digital elevation model (DEM) of the basin| such as air temperature| precipitation| snowfall ratio| wind speed| etc.| have been used as model input. Several other hydrological parameters| such as soil moisture content and evapotranspiration| which are essential in simulation of river runoff in a water balance state| were estimated by the combination of Landsat TM and a DEM with the utilization of the distributed meteorological data. The model uses only a few crucial parameters for calibration| and the model structure is based upon estimating the stream flow components. Simulated results of spatially distributed soil moisture content| evapotranspiration and monthly discharge yield reasonable agreement| both spatially and temporally| to the field observations or the estimated results by the other approaches. This physically based model has the potential to project stream flow under the possible climate scenarios. Copyright (C) 2000 John Wiley & Sons| Ltd. 5304,2000,3,4,A novel type of catalytic copper cluster in nitrous oxide reductase,Nitrous oxide (N(2)O) is a greenhouse gas| the third most significant contributor to global warming. As a key process for N(2)O elimination from the biosphere| N(2)O reductases catalyze the two-electron reduction of N(2)O to N(2). These 2 x 65 kDa copper enzymes are thought to contain a CuA electron entry site| similar to that of cytochrome c oxidase| and a CuZ catalytic center. The copper anomalous signal was used to solve the crystal structure of N(2)O reductase from Pseudomonas nautica by multiwavelength anomalous dispersion| to a resolution of 2.4 Angstrom. The structure reveals that the CuZ center belongs to a new type of metal cluster| in which four copper ions are liganded by seven histidine residues. N(2)O binds to this center via a single copper ion. The remaining copper ions might act as an electron reservoir| assuring a fast electron transfer and avoiding the formation of dead-end products. 5285,2000,4,3,A regime view of northern hemisphere atmospheric variability and change under global warming,The leading mode of wintertime variability in Northern Hemisphere sea level pressure (SLP) is the Arctic Oscillation (AO). It is usually obtained using linear principal component analysis| which produces the optimal| although somewhat restrictive| linear approximation to the SLP data. Here we use a recently introduced nonlinear principal component analysis to find the optimal nonlinear approximation to SLP data produced by a 1001 year integration of the CCCma coupled general circulation model (CGCM1). This approximation's associated time series is strongly bimodal and partitions the data into two distinct regimes. The first and more persistent regime describes a standing oscillation whose signature in the mid-troposphere is alternating amplification and attenuation of the climatological ridge over Northern Europe; with associated decreasing and increasing daily variance over Northern Eurasia. The second and more episodic regime describes a split-flow south of Greenland with much enhanced daily variance in the Arctic. In a 500 year integration with atmospheric CO2 stabilized at concentrations projected for year 2100| the occupation statistics of these preferred modes of variability change| such that the episodic split-flow regime occurs less frequently while the standing oscillation regime occurs more frequently. 5173,2000,2,4,A relict population of Fagus grandifolia var. mexicana at the Acatlan Volcano| Mexico: structure| litterfall| phenology and dendroecology,Aim Fagus grandifolia var. mexicana (Martinez) Little has an extraordinarily restricted distribution in the Mexican montane cloud forests. Isolated Fagus (beech) populations have been recorded in less than 10 small areas (2-40 ha) in the eastern Sierra Madre at altitudes from 1400 to 2000 m. The objectives were to determine tree and seedling age| forest structure| phenology| litterfall patterns and the relationship between mast and climatic variables. Location We report on three Fagus stands at the Acatlan Volcano| Veracruz| Mexico. Methods Changes in forest cover were determined using aerial photographs. Within each stand| basal area| density and tree species composition were determined in a 0.1-ha band transect. Additionally| litterfall production was quantified and phenophases were recorded monthly over a 3-year period| and 60 tree cores were collected to determine age distribution and tree-ring growth. Results The forest was atypical in several respects. Fagus was the only dominant tree species in the crater stand| although in the rim and at the top of the volcano it was codominant with other tree species. Juveniles occurred only on the rim| but there was a seedling bank in the crater. Although forest cover in the area increased between 1968 and 1993| the Fagus stands did not change in size. Leaf production peaked in March and April| and leaf fail occurred from October through February. Litterfall production was the highest in November. During mast years| flowering started in February and between mast events there were no flowers or fruits. Minimum temperatures were highly correlated with Fagus litterfall and leaf fall. Seedlings ranged in age from 2 to 18 years and were 13-60 cm tall. Tree cores ranged from 76 to 120 years| but trees were older than the core samples. Main conclusions Although beech is considered a gap regeneration species that reaches the canopy after alternating periods of release and suppression| the trees in the crater were released when less than 1.5 m tall and have suffered few periods of suppression since. The results indicate that the crater stand was established after a severe disturbance destroyed the existing forest. We conclude that the relict beech population should be able to maintain itself| if not severely disturbed by humans or by climatic changes related to global warming. 5371,2000,2,4,A sensitivity study of the thermodynamic environment on GFDL model hurricane intensity: Implications for global warming,In this study| the effect of thermodynamic environmental changes on hurricane intensity is extensively investigated with the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory hurricane model for a suite of experiments with different initial upper-tropospheric temperature anomalies up to +/-4 degrees C and sea surface temperatures ranging from 26 degrees to 31 degrees C given the same relative humidity profile. The results indicate that stabilization in the environmental atmosphere and sea surface temperature (SST) increase cause opposing effects on hurricane intensity. The offsetting relationship between the effects of atmospheric stability increase (decrease) and SST increase (decrease) is monotonic and systematic in the parameter space. This implies that hurricane intensity increase due to a possible global warming associated with increased CO2 is considerably smaller than that expected from warming of the oceanic waters alone. The results also indicate that the intensity of stronger (weaker) hurricanes is more (less) sensitive to atmospheric stability and SST changes. The model-attained hurricane intensity is found to be well correlated with the maximum surface evaporation and the large-scale environmental convective available potential energy. The model-attained hurricane intensity is highly correlated with the energy available from wet-adiabatic ascent near the eyewall relative to a reference sounding in the undisturbed environment for all the experiments. Coupled hurricane-ocean experiments show that hurricane intensity becomes less sensitive to atmospheric stability and SST changes since the ocean coupling causes larger (smaller) intensity reduction for stronger (weaker) hurricanes. This implies less increase of hurricane intensity related to a possible global warming due to increased CO2. 5300,2000,4,4,A simple coupled atmosphere-ocean-sea ice-land surface model for climate and paleoclimate studies,The authors develop a coupled atmosphere-ocean-sea ice-land surface: model for long-term climate change studies that incorporates the seasonal cycle. Three ocean basins. the Antarctic Circumpolar Current region| and the major continents are resolved. The model variables are sectorially averaged across the different ocean basins and continents. The atmosphere is represented by an energy-moisture balance model in which the meridional energy and moisture transports are parameterized by a combination of advection and diffusion processes. The zonal heat transport between land and ocean obeys a diffusion law| while the zonal moisture transport is parameterized so that the ocean always supplies moisture to the land. The ocean model is due to Wright and Stocker| and the sea ice model is a zero-layer thermodynamic one in which the ice thickness and concentration are predicted by the methods of Semtner and Hibler| respectively. In the land surface model| the temperature is predicted by an energy budget equation| similar to Ledley's| while the soil moisture and river runoff are predicted by Manabe's bucket model. The above model components are coupled together using flux adjustments in order to first simulate the present day climate. The major features of this simulation are consistent with observations and the general results of GCMs. However| it is found that a diffusive law for heat and moisture transports fives better results in the Northern Hemisphere than in the Southern Hemisphere. Sensitivity experiment| show that in a global warming (cooling) experiment| the thermohaline circulation (THC) in the North Atlantic Ocean is weakened (intensified) due to the increased (reduced) moisture transport to the northern high latitudes and the warmer (cooler) SST at northern high latitudes. Last| the coupled model is employed to investigate the initiation of glaciation by slowly reducing the solar radiation and increasing the planetary emissivity| only in the northern high latitudes. When land ice is growing| the THC in the North Atlantic Ocean is intensified| resulting in a warm subpolar North Atlantic Ocean. which is in agreement with the observations of Ruddiman and McIntyre. The intensified THC maintains a large land-ocean thermal contrast at high latitudes and hence enhances land ice accumulation| which is consistent with the rapid ice sheet growth during the first 10 kyr of the last glacial period that was observed by Johnson and Andrews. The authors conclude that a cold climate is not responsible for a weak ol collapsed THC in the North Atlantic Ocean: rather it is suggested that increased freshwater or massive iceberg discharge from land is responsible for such a state. 3124,2000,2,3,A simulation of biomes on the Tibetan Plateau and their responses to global climate change,The improved process based equilibrium terrestrial biosphere model (BIOME3China) was run under the present climate to model the potential biomes on the Tibetan Plateau on a 10' grid. The simulated biome was basically in good agreement with a potential natural vegetation map based on a numerical comparison between two maps using the Delta V statistic (Delta V = 0.38). A coupled ocean- atmosphere general circulation model including sulfate aerosols was used to drive a double greenhouse gas scenario to the end of the next century. The simulated vegetation under changed climate with a CO:! concentration of 500 ppmv and a baseline biome map were also compared using the Delta V statistic (Delta V = 0.4). The climate change would cause a large reduction in the temperate deserts alpine steppe| desert| and ice/polar desert| a large increase in the cold-temperate conifer forest| temperate shrubland/meadow| and temperate steppe| and a general northwestward shift of ail vegetation zones. In addition to simulation of biome distribution| BIOME3China also predicted net primary production (NPP) of each grid cell. Comparisons between predicted annual NPP and 160 forest NPP measurements show an agreement between them with a linear regression| despite many problems| such as the quality of the field data. The pattern of predicted annual NPP in the scenario with enhanced CO2 concentration was the same as that under the present climate; however| the NPP of each biome would increase significantly. Present permafrost simulated using the air frost index was quite similar to the actual frozen ground distribution on the Tibetan Plateau. After the change in climate| the boundary between continuous and discontinuous permafrost would shift toward the north of the plateau by about 1-2 degrees in latitude. The continuous permafrost would mostly disappear| whereas the no-permafrost area would greatly increase. The movement of permafrost would take place with the shift of vegetation zones to the north. The disappearance of permafrost and the expansion of no-permafrost areas would accelerate the desertification of the Tibetan Plateau. 5163,2000,4,2,Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model,The continued increase in the atmospheric concentration of carbon dioxide due to anthropogenic emissions is predicted to lead to significant changes in climate(1). About half of the current emissions are being absorbed by the ocean and by land ecosystems(2)| but this absorption is sensitive to climate(3|4) as well as to atmospheric carbon dioxide concentrations(5)| creating a feedback loop. General circulation models have generally excluded the feedback between climate and the biosphere| using static vegetation distributions and CO2 concentrations from simple carbon-cycle models that do not include climate change(6). Here we present results from a fully coupled| three-dimensional carbon-climate model| indicating that carbon-cycle feedbacks could significantly accelerate climate change over the twenty-first century. We rnd that under a 'business as usual' scenario| the terrestrial biosphere acts as an overall carbon sink until about 2050| but turns into a source thereafter. By 2100| the ocean uptake rate of 5 Gt Cyr(-1) is balanced by the terrestrial carbon source| and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models(2)| resulting in a global-mean warming of 5.5 K| as compared to 4 K without the carbon-cycle feedback. 5344,2000,4,4,Acclimation of photosynthesis to temperature in eight cool and warm climate herbaceous C-3 species: Temperature dependence of parameters of a biochemical photosynthesis model,To determine how parameters of a Farquhar-type photosynthesis model varied with measurement temperature and with growth temperature| eight cool and warm climate herbaceous crop and weed species were grown at 15 and 25 degrees C and single leaf carbon dioxide and water vapor exchange rates were measured over the range of 15 - 35 degrees C. Photosynthetic parameters examined were the initial slope of the response of assimilation rate (A) to substomatal carbon dioxide concentration (C-i)| A at high C-i| and stomatal conductance. The first two measurements allow calculation of V-Cmax| the maximum rate of carboxylation of ribulose bisphosphate carboxylase and J(max)| the maximum rate of photosynthetic electron transport| of Farquhar-type photosynthesis models. In all species| stomatal conductance increased exponentially with temperature over the whole range of 15 - 35 degrees C| even when A decreased at high measurement temperature. There were larger increases in conductance over this temperature range in the warm climate species (4.3 x) than in the cool climate species (2.5 x). The initial slope of A vs. C-i exhibited an optimum temperature which ranged from 20 to 30 degrees C. There was a larger increase in the optimum temperature of the initial slope at the warmer growth temperature in the cool climate species than in the warm climate species. The optimum temperature for A at high C-i ranged from 25 to 30 degrees C among species| but changed little with growth temperature. The absolute values of both the initial slope of A vs. C-i and A at high C-i were increased about 10% by growth at the warmer temperature in the warm climate species| and decreased about 20% in the cool climate species. The ratio of J(max) - V-Cmax normalized to 20 degrees C varied by more than a factor of 2 across species and growth temperatures| but differences in the temperature response of photosynthesis were more related to variation in the temperature dependencies of J(max) and V-Cmax than to the ratio of their normalized values. 5343,2000,2,4,Acclimation to temperature of the response of photosynthesis to increased carbon dioxide concentration in Taraxacum officinale,The relative stimulation of photosynthesis by elevated carbon dioxide in C-3 species normally increases strongly with increasing temperature. This results from the kinetic characteristics of Rubisco| and has potentially important implications for responses of vegetation to increasing atmospheric carbon dioxide. It is often assumed that because Rubisco characteristics are conservative| all C-3 species have the same temperature dependence of the response of photosynthesis to elevated carbon dioxide. However| in this field study of Taraxacum officinale| there were no significant differences in the relative stimulation of photosynthesis by elevated carbon dioxide among days with temperatures ranging from 15 to 34 degreesC. Nevertheless| short-term measurements indicated a strong temperature dependence of the stimulation. This suggested that acclimation to temperature caused the lack of variation in the seasonal data. Experiments in controlled environments indicated that complete acclimation of the relative stimulation of photosynthesis by elevated carbon dioxide occurred for growth temperatures of 10 - 25 degreesC. The apparent specificity of Rubisco for carbon dioxide relative to oxygen at 15 degreesC| as assayed in vivo by measurements of the carbon dioxide concentration at which carboxylation equalled oxygenation| also varied with growth temperature. Changes in the apparent specificity of Rubisco accounted for the acclimation of the temperature dependence of the relative stimulation of photosynthesis by elevated carbon dioxide. It is premature to conclude that low temperatures will necessarily reduce the relative stimulation of photosynthesis caused by rising atmospheric carbon dioxide. 3117,2000,3,2,Adaptation to what and why?,Adaptation in response to anthropogenic climate change seeks to maintain viability by maximising benefits and minimising losses. It is necessary because some climatic change is now inevitable| despite the international focus on mitigation measures. Indeed| the measures agreed at Kyoto would by themselves result in only a small reduction in the climate changes to be expected over the next century. Discussion of the expected changes and possible impacts leads to the following conclusions regarding climate change scenarios in relation to impacts and adaptation: Climate change in the foreseeable future will not be some new stable "equilibrium" climate| but rather an ongoing "transient" process; Climate change predictions relevant to impacts on most sectors and ecosystems are still highly uncertain; There is a need for a greater focus on developing countries and tropical regions| and on relevant key variables| including the magnitude and frequency of extreme events; The focus should shift from single predictions| or extreme ranges of uncertainty| to risk assessment; Thresholds critical to impacted sectors and ecosystems should be identified| and expressed as functions of climatic variables; Planned adaptations will be necessary to cope with multiple stresses| including those due to non-climatic changes; A major task of adaptation science is to identify the limits of adaptation| i.e.| to identify "dangerous levels of greenhouse gases" beyond which adaptation becomes impractical or prohibitively expensive. 3111,2000,4,4,Age of soil organic matter and soil respiration: Radiocarbon constraints on belowground C dynamics,Radiocarbon data from soil organic matter and soil respiration provide powerful constraints for determining carbon dynamics and thereby the magnitude and timing of soil carbon response to global change. In this paper| data from three sites representing well-drained soils in boreal| temperate| and tropical forests are used to illustrate the methods for using radiocarbon to determine the turnover times of soil organic matter and to partition soil respiration. For these sites| the average age of bulk carbon in detrital and Oh/A-horizon organic carbon ranges from 200 to 1200 yr. In each case| this mass-weighted average includes components such as relatively undecomposed leaf| root| and moss litter with much shorter turnover times| and humified or mineral-associated organic matter with much longer turnover times. The average age of carbon in organic matter is greater than the average age predicted for CO| produced by its decomposition (30| 8| and 3 yr for boreal| temperate| and tropical soil)| or measured in total soil respiration (16| 3| and 1 yr). Most of the CO2 produced during decomposition is derived from relatively short-lived soil organic matter (SOM) components that do not represent a large component of the standing stock of soil organic matter. Estimates of soil carbon turnover obtained by dividing C stocks by heterotrophic respiration fluxes| or from radiocarbon measurements of bulk SOM| are biased to longer time scales of C cycling. Failure to account for the heterogeneity of soil organic matter will result in underestimation of the short-term response and overestimation of the long-term response of soil C storage to future changes in inputs or decomposition. Comparison of the C-14 in soil respiration with soil organic matter in temperate and boreal forest sites indicates a significant contribution from decomposition of organic matter fixed >2 yr but <30 yr ago. Tropical soil respiration is dominated by C fixed <1 yr ago. Monitoring the C-14 signature of CO2 emitted from soils give clues as to the causes of seasonal and interannual variability in soil respiration in these systems. 3135,2000,4,4,Airborne laser mapping of Assateague National Seashore beach,Results are presented from topographic surveys of the Assateague Island National Seashore using an airborne scanning laser altimeter and kinematic Global Positioning System (GPS) technology. The instrument used was the Airborne Topographic Mapper (ATM)| developed by the NASA Arctic Ice Mapping (AIM) group from the Goddard Space Flight Center's Wallops Flight Facility. In November| 1995| and again in May| 1996| these topographic surveys were flown as a functionality check prior to conducting missions to measure the elevation of extensive sections of the Greenland Ice Sheet as part of NASA's Global Climate Change program. Differences between overlapping portions of both surveys are compared for quality control. An independent assessment of the accuracy of the ATM survey is provided by comparison to surface surveys which were conducted using standard techniques. The goal of these projects is to make these measurements to an accuracy of +/- 10 cm. Differences between the fall 1995 and 1996 surveys provides an assessment of net changes in the beach morphology over an annual cycle. 5281,2000,2,4,Albumax and global warming on the web,An entomologist| Paul Reiter from Centers for Disease Control & Prevention| Puerto Rico| informed the ProMed list that ‘8 of 9 web pages dealing with this subject put the danger of malaria migrating to the United States and Europe as the number 1 danger caused by global warming'. Likewise| dengue and yellow fever are predicted to move to temperate climes. To put the subject in perspective| he had written an article entitled ‘From Shakespeare to Defoe: Malaria in England in the Little Ice Age' (see http://www.cdc.gov/ncidod/eid/vol6no1/reiter.htm and published by the CDC| Vol. 6| Jan–Feb 2000). He wanted comments. [This fascinating article provides evidence to show that malaria was endemic in many temperate regions until the second half of the 20th century| causing major epidemics even as far north as the Arctic Circle| and it started to decline only in the 19th century when the present warming trend was already under way.] When Paul Roughan (University of Canterbury| New Zealand) asked the malaria list about the possible impact of global climate change (in particular| the spread of tropical zones) on the range of malaria| Ruth Sponsler| another entomologist| recommended Reiter's paper| emphasizing the impact that changes in living conditions have had on its transmission. Pia MacDonald (University of Michigan| USA) sent 31 references| covering papers from 1942 to 1998. Sander Koenraadt (Wageningen University| The Netherlands) described a project under way (see http://www.icis.unimaas.nl/camera) concerned with the effect of climate change on the vectors of malaria and designed to develop a model to predict changes in the incidence of the disease in the highlands| and in areas north and south of the current distribution area which might be affected.
3106,2000,2,4,Altering rainfall timing and quantity in a mesic grassland ecosystem: Design and performance of rainfall manipulation shelters,Global climate change is predicted to alter growing season rainfall patterns| potentially reducing total amounts of growing season precipitation and redistributing rainfall into fewer but larger individual events. Such changes may affect numerous soil| plant| and ecosystem properties in grasslands and ultimately impact their productivity and biological diversity. Rainout shelters are useful tools for experimental manipulations of rainfall patterns| and permanent fixed-location shelters were established in 1997 to conduct the Rainfall Manipulation Plot study in a mesic tallgrass prairie ecosystem in northeastern Kansas. Twelve 9 x 14-m fixed-location rainfall manipulation shelters were constructed to impose factorial combinations of 30% reduced rainfall quantity and 50% greater interrainfall dry periods on 6 x 6-m plots| to examine how altered rainfall regimes may affect plant species composition| nutrient cycling| and above- and belowground plant growth dynamics. The shelters provided complete control of growing season rainfall patterns| whereas effects on photosynthetic photon flux density| nighttime net radiation| and soil temperature generally were comparable to other similar shelter designs. Soil and plant responses to the first growing season of rainfall manipulations (1998) suggested that the interval between rainfall events may be a primary driver in grassland ecosystem responses to altered rainfall patterns. Aboveground net primary productivity| soil CO2 flux| and flowering duration were reduced by the increased interrainfall intervals and were mostly unaffected by reduced rainfall quantity. The timing of rainfall events and resulting temporal patterns of soil moisture relative to critical times for microbial activity| biomass accumulation| plant life histories| and other ecological properties may regulate longer-term responses to altered rainfall patterns. 3137,2000,2,4,Alternative forest management strategies under climatic change - Prospects for gap model applications in risk analyses,The projected global climate change will influence growth and productivity of natural and managed forests. Since the characteristics of the future regional climate are still uncertain and the response of our forests to changes in the atmospheric and climatic conditions may be both positive or negative| decision making in managed forests should consider the new risks and uncertainties arising from climatic change| especially if the rotation periods are long. An extended version of the forest gap model FORSKA was applied to simulate the forest development at 488 forest inventory plots in the federal state of Brandenburg| Germany| under two climate and three management scenarios. The transient growth dynamics from 1990 to 2100 were investigated at four sites in different parts of the state| representing the variability of environmental and forest conditions within Brandenburg. The alternative management strategies led to distinct differences in forest composition after 110 years of simulation. The projected climate change affected both forest productivity and species composition. The impacts of alternative management scenarios are discussed. It is concluded that the extended forest gap model can be a valuable tool to support decision making in forest management under global change. 5362,2000,5,2,Amazonian and neotropical plant communities on glacial time-scales: The failure of the aridity and refuge hypotheses,Plants respond to Pleistocene climatic change as species| not as associations or biomes. This has been demonstrated unequivocally by paleobotanical data for temperate latitudes. In the far richer vegetations of the tropics species populations also fluctuated independently in response to climatic forcing| from their longlasting glacial states to the patterns of brief interglacials like the present and back again. We use pollen data to reconstruct the vegetation of the Amazon basin in oxygen isotope stages 3 and 2 of the last glaciation in order to measure how the plant populations of the Amazon responded to the global warming at the onset of the Holocene. We find that plant communities of the neotropics vent copious pollen to lake sediments and that this pollen yields powerful signals for community composition. Three continuous sedimentary records reaching through oxygen isotope stage 2 are available from the Amazon lowlands| those from Carajas| Lake Pata and marine deposits off the mouth of the Amazon River. All three records yield pollen histories of remarkable constancy and stability. By comparing them with deposits of equal antiquity from the cerrado (savanna) of central Brazil| we show that most of the Amazon lowlands remained under forest throughout a glacial cycle. This forest was never fragmented by open vegetation as postulated by the refugia hypothesis. Instead the intact forest of glacial times included significant populations of plants that are now montane| suggesting that the global warming of the early Holocene resulted in the expulsion of heat intolerant plants from the lowland forest. Pollen data from the Amazonian flank of the Andes and from Pacific Panama provide evidence that populations of these heat intolerant plants survive the heat of interglacials in part by maintaining large populations at cooler montane altitudes. Our conclusion that the Amazon lowlands were forested in glacial times specifically refutes the hypothesis of Amazonian glacial aridity. Accordingly we examine the geomorphological evidence for glacial aridity and find it wanting. Of the three paleodune systems reported for tropical South America| that of NE Brazil was active in the Holocene as well as the Pleistocene. Parts of NE Brazil were actually moister than now in late-glacial times. Paleodunes in the Pantanal have never been seen on the ground| and those in the Orinoco Llanos are undated and may bie of any age since the Tertiary. Arkosic sands in the Amazon fan deposits came from the Andean foothills or from down cutting by rivers and cannot be evidence of a former arid land surface. White sands of Amazonia formed as podzols| not by aeolian activity. Such Amazonian stone lines as have received critical scrutiny are concretionary pisolites in stratigraphic formations that are more than ten million years old. Although the Amazon was never arid| modeling cooler glacial tropics gives plausibility to a somewhat drier Amazon in glacial times| a concept given substance by pollen data for the movement of ecotones in Rondonia| by stream histories in the Bolivian Andes| and by evidence for lowered lake levels at Carajas and Lake Pata. But this reduced precipitation was never enough to fragment the forest in the Amazon lowlands themselves. Pleistocene mammals of the Napo river valley in Ecuador were able to live along the river system in a forested landscape. Our data suggest that the Amazon forests have been stable since the start of the Pleistocene| a fact that has contributed to the storage of vast diversity. The coming anthropogenic global warming and CO2 enrichment will add to the global warming already endured by Amazon biota in the Holocene. We think it possible that the expulsion from the lowland forests of heat intolerant species is already complete and that the forest property of maintaining its own microhabitat will allow the high species richness to survive more global warming| provided large enough tracts of forest are preserved. (C) 1999 Elsevier Science Ltd. All rights reserved. 3072,2000,4,4,AMS at ANTARES - The first 10 years,The status and capabilities of the ANTARES AMS facility after 10 years are reviewed. The common AMS radioisotopes| Be-10| C-14| Al-26| Cl-26 and I-129| routinely analysed. A capability for the detection of U-236 and other actinide isotopes has been developed. The measurement program includes support to Quaternary science projects at Australian universities and to ANSTO projects in global climate change and nuclear safeguards. (C) 2000 Elsevier Science B.V. All rights reserved. 5322,2000,3,2,An evaluation of historical methane emissions from the Soviet gas industry,An inventory of natural gas losses from the former Soviet Union's gas industry has been constructed from published Russian-language sources. The results imply that in the late 1980s/early 1990s annual losses from Russia were in the range 35-59 x 10(9) cubic meters (24-40 Tg of CH4): estimates based on what are thought to be the more reliable sources place annual losses in the range 37-52 x 10(9) cubic meters (25-35 Tg of CH4). Of this amount| one half to two thirds of the emissions may have been from the extremely long and ageing gas pipeline system. Extrapolation of the estimates for Russian losses to the whole territory of the former Soviet Union suggests a probable total annual emission level from the whole ex-Soviet gas industry in the range 47-67 x 10(9) cubic meters of natural gas or 31-45 Tg of CH4 in these years. The envelope of minimum and maximum estimates for emissions from the former Soviet Union ranges from 29 to 50 Tg of methane. The limited availability of systematic and accurate published information on the emissions introduces significant uncertainty into the estimate. In an attempt to constrain emissions better| estimates of losses from specific causes were made using two or more independent approaches| where possible. A reasonable agreement between estimates was achieved in those cases. Our results imply that substantial reductions in emissions could be achieved by investment to reduce losses. Because of the high global warming potential and short lifetime of methane compared to carbon dioxide| reducing the large losses from the FSU may be among the most cost-effective short-term approaches available to reduce global anthropogenic greenhouse warming. 5348,2000,3,3,An evaluation of multicriteria decision-making methods in integrated assessment of climate policy,Those who conduct integrated assessments (IAs) are increasingly aware of the need to explicitly consider uncertainty and a range of criteria when evaluating alternative policies for preventing global warming. Multi-criteria decision-making (MCDM) methods provide a useful set of tools for understanding tradeoffs and gaining insight into policy alternatives. A difficulty facing potential MCDM users is the multitude of different techniques| each with distinct advantages and disadvantages. Methods differ widely in terms of their ease of use and appropriateness to the issue under consideration. Most importantly| different methods can yield strikingly different rankings of alternatives. A workshop was held to expose climate change experts| IA researchers| and policy makers to a range of MCDM methods and to evaluate and compare their potential usefulness to IA. Participants applied several methods in the context of a hypothetical greenhouse gas policy decision and evaluated each method. Analysis of method results and participant feedback through questionnaires and discussion provide the basis for conclusions regarding the use of MCDM methods for climate change policy and IA analysis. 5379,2000,4,4,An in situ experiment of methane sequestration as gas hydrate| authigenic carbonate| and loss to the water column and/or atmosphere,A one year in situ experiment to quantify the flux of carbon| primarily as methane| from an overpressured thrust fault at the Cascadia convergent margin (ODP Site 892B) is described| Most of the expelled carbon Is sequestered in two solid phases| methane hydrate and authigenic carbonates and an unknown portion is lost in the water column and/or atmosphere| C-14 ages of clam shells from the vicinity of the site suggest active methane venting for at least 21-24 kyrs. The water column chemistry provides information on the potential effects of global warming on rapid massive gas hydrate dissociation and on the effects of microbial oxidation of the released methane on the local oceanic oxygen and CO2 contents. The local and global implications of these processes for the oceanic carbon cycle are being assessed. 5365,2000,5,4,Annual climate variability in the Holocene: interpreting the message of ancient trees,Over vast areas of the world's landmasses| where climate beats out a strong seasonal rhythm| tree growth keeps unerring time. In their rings| trees record many climate melodies| played in different places and different eras. Recent years have seen a consolidation and expansion of tree-ring sample collections across the traditional research areas of North America and Europe| and the start of major developments in many new areas of Eurasia| South America and Australasia. From such collections are produced networks of precisely dated chronologies; records of various aspects of tree growth| registered continuously| year by year across many centuries. Their sensitivities to different climate parameters are now translated into ever more detailed histories of temperature and moisture variability across expanding dimensions of time and space. With their extensive coverage| high temporal resolution and rigid dating control| dendroclimatic reconstructions contribute significantly to our knowledge of late Holocene climates| most importantly on timescales ranging from 1 to 100 years. In special areas of the world| where trees live for thousands of years or where subfossil remnants of long dead specimens are preserved| work building chronologies covering many millennia continues apace. Very recently| trees have provided important new information about major modes of general circulation dynamics linked to the El Nino/Southern Oscillation and the North Atlantic Oscillation| and about the effect of large volcanic eruptions. As for assessing the significance of 20th century global warming| the evidence from dendroclimatology in general| supports the notion that the last 100 years have been unusually warm| at least within a context of the last two millennia. However| this evidence should not be considered equivocal. The activities of humans may well be impacting on the 'natural' growth of trees in different ways| making the task of isolating a clear climate message subtly difficult. (C) 1999 Elsevier Science Ltd. All rights reserved. 5279,2000,3,4,Appliance rigid foams blown with cyclopentane and cyclopentane/isopentane blends,Since CFC 11 was eliminated from use in rigid foams in the mid 1990s| the blowing agent of choice in North America has primarily been HCFC 141b. In the USA| we are now faced with the phase-out of HCFC 141b by the year 2003. The blowing agent that will replace HCFC 141b must be non-ozone depleting and should also have low thermal conductivity and a low global warming potential. Hydrocarbons are some of the few blowing agents that meet these criteria and are approved by the United States Environmental Protection Agency to replace HCFC 141b in rigid polyurethane foams for appliance insulation [1]. Of the hydrocarbons being considered| cyclopentane is preferred| either by itself or in blends with other hydrocarbons. This is because of cyclopentane's favorable combination of low thermal conductivity| good solubility in polyols and reasonable boiling point| compared to other hydrocarbons. Not only is the thermal conductivity of cyclopentane lower than that of most other hydrocarbons| it is also lower than that of HFC 134a| another blowing agent which is approved for use after 2002. This paper will examine the effect of two important factors| both theoretically and experimentally| on cyclopentane blown foams. These factors are (1) the amount of blowing obtained from carbon dioxide that is formed from the reaction between water and isocyanate| and (2) the ratio of cyclopentane to isopentane| which is used as the hydrocarbon blowing agent. 5222,2000,3,3,Assessing fuel substitution from coal to natural gas for power plants in compliance with FCCC provisions,A number of environmental strategies in compliance with the provisions of the Framework Convention on Climate Change (FCCC) are currently being analyzed by utilities. Natural gas is often the most important one| since its use emits carbon dioxide (CO2) far less than other fossil fuels. The use of natural gas is therefore under serious consideration as a strategy to reduce the impact on global warming from coal thermal plants under current technological levels. In this article| a cost minimization model is formulated to investigate the feasibility for this strategy from a long-term economic viewpoint. The model developed is comprised of various strategies such as installing scrubbers| purchasing emission credits| or switching fuels for fossil plants| especially coal-fired thermals| which are currently being implemented or considered by utilities. The implemented results show that substitution of natural gas is less economical than other strategies. 5273,2000,4,3,Atmospheric centers of action and tendencies of their change,Tendencies of change in the characteristics of atmospheric centers of action (ACAs) in the Northern Hemisphere are analyzed using empirical data over the period 1891-1995. The results are compared to model estimates. The hydrostatic equation is used to obtain the simplest model estimates. A more detailed model is based on the consideration of quasi-stationary Rossby waves on a sphere at the equivalent-barotropic level. For the mode with a meridional wave number of 5 and with a zonal wave number of 2| which makes a major contribution to the formation of Northern Hemisphere ACAs| the relative dynamics of the pressure and temperature fields at the equivalent-barotropic level is analyzed analytically. The interrelation between the corresponding surface fields is estimated with allowance for a relationship between the tropospheric lapse rate and the surface air temperature. The resulting model expressions can be used for a qualitative analysis of the relative role of various climatic variables in the formation of the sensitivity of ACA characteristics to global changes| both anthropogenic| caused by changes in the atmospheric contents of greenhouse gases and aerosol| and natural| associated| for example| with phenomena like El Nino. Model estimates are used to explain a possible strengthening of ACA intensity under global warming of the climate| which is detected| in particular| for the wintertime Siberian High by analyzing empirical data. The corresponding tendencies of change in the ACA location (latitude and longitude) are estimated. 3128,2000,2,4,Atmospheric CO2 and the composition and function of soil microbial communities,Elevated atmospheric CO2 has the potential to increase the production and alter the chemistry of organic substrates entering soil from plant production| the magnitude of which is constrained by soil-N availability. Because microbial growth in soil is limited by substrate inputs from plant production| we reasoned that changes in the amount and chemistry of these organic substrates could affect the composition of soil microbial communities and the cycling of N in soil. We studied microbial community composition and soil-N transformations beneath Populus tremuloides Michx. growing under experimental atmospheric CO2 (35.7 and 70.7 Pa) and soil-N-availability (low N = 61 ng N.g(-1).d(-1) and high N = 319 ng N.g(-1).d(-1)) treatments. Atmospheric CO2 concentration was modified in large| open-top chambers| and we altered soil-N availability in open-bottom root boxes by mixing different proportions of A and C horizon material. We used phospholipid fatty-acid analysis to gain insight into microbial community composition and coupled this analysis to measurements of soil-N transformations using N-15-pool dilution techniques. The information presented here is part of an integrated experiment designed to elucidate the physiological mechanisms controlling the flow of C and N in the plant-soil system. Our objectives were (1) to determine whether changes in plant growth and tissue chemistry alter microbial community composition and soil-N cycling in response to increasing atmospheric CO2 and soil-N availability and (2) to integrate the results of our experiment into a synthesis of elevated atmospheric CO2 and the cycling of C and N in terrestrial ecosystems. After 2.5 growing seasons| microbial biomass| gross N mineralization| microbial immobilization| and nitrification (gross and net) were equivalent at ambient and elevated CO2| suggesting that increases in fine-root production and declines in fine-root N concentration were insufficient to alter the influence of native soil organic matter on microbial physiology; this was the case in both low- and high-N soil. Similarly| elevated CO2 did not alter the proportion of bacterial| actinomycetal| or fungal phospholipid fatty acids in low-N or high-N soil| indicating that changes in substrate input from greater plant growth under elevated CO2 did not alter microbial community composition. Our results differ from a substantial number of studies reporting increases and decreases in soil-N cycling under elevated CO2. From our analysis| it appears that soil-N cycling responds to elevated atmospheric CO2 in experimental situations where plant roots have fully colonized the soil and root-associated C inputs are sufficient to modify the influence of native soil organic matter on microbial physiology. In young developing ecosystems where plant roots have not fully exploited the soil| microbial metabolism appears to be regulated by relatively large pools of soil organic matter| rather than by the additional input of organic substrates under elevated CO2. 3127,2000,2,4,Atmospheric CO2| soil-N availability| and allocation of biomass and nitrogen by Populus tremuloides,Our ability to predict whether elevated atmospheric CO2 will alter the cycling of C and N in terrestrial ecosystems requires understanding a complex set of feedback mechanisms initiated by changes in C and N acquisition by plants and the degree to which changes in resource acquisition (C and N) alter plant growth and allocation. To gain further insight into these dynamics| we grew six genotypes of Populus tremuloides Michx. that differ in autumnal senescence (early vs| late) under experimental atmospheric CO2 (35.7 and 70.7 Pa) and soil-N availability (low and high) treatments. Atmospheric CO2 concentrations were manipulated with open-top chambers| and soil-N availability was modified in open-bottom root boxes by mixing different proportions of native A and C horizon soil. Net N mineralization rates averaged 61 ng N.g(-1).d(-1) in low-N soil and 319 ng N.g(-1).d(-1) in high-N soil. After 2.5 growing seasons| we harvested above- and belowground plant components in each chamber and determined total biomass| N concentration| N content| and the relative allocation of biomass and N to leaves| stems| and roots. Elevated CO2 increased total plant biomass 16% in low-N soil and 38% in high-N soil| indicating that the growth response of P. tremuloides to elevated CO2 was constrained by soil-N availability. Greater growth under elevated CO2 did not substantially alter the allocation of biomass to above- or belowground plant components. At both levels of soil-N availability| elevated CO2 decreased the N concentration of all plant tissues. Despite declines in tissue N concentration| elevated CO2 significantly increased whole-plant N content in high-N soil (ambient = 137 g N/chamber; elevated = 155 g N/chamber)| but it did not influence whole-plant N content in low-N soil (36 g N/chamber). Our results indicate that plants in high-N soil obtained greater amounts of soil N under elevated CO2 by producing a proportionately larger fine-root system that more thoroughly exploited the soil. The significant positive relationship between fine-root biomass and total-plant N content we observed in high-N soil further supports this contention. In low-N soil| elevated CO did not increase fine-root biomass or production| and plants under ambient and elevated CO2 obtained equivalent amounts of N from soil. In high-N soil| it appears that greater acquisition of soil N under elevated CO2 fed forward within the plant to increase rates of C acquisition| which further enhanced plant growth response to elevated CO2. 5228,2000,4,4,Avian data bases and their use in environmental assessment,The databases of the British Trust for Ornithology that can be used in environmental assessment are described. The most important ongoing surveys from this viewpoint are as follows: the Ringing Scheme which gives information on annual mortality| the Nest Record Card Scheme which provides data on reproductive success| the Common Birds Census which gives an index of population| the Constant Effort Sites which monitors productivity and survival and the Breeding Bird Survey which complements and is replacing the Common Birds Census. The use of these databases in unravelling the effects of intensive agriculture on avian populations is discussed. The use of these databases to monitor global warming is also considered. 5223,2000,2,4,Bad air for coral reefs,Specialists have seriously worried about coral reefs for the last 15 years. These biological constructions have survived all sorts of challenges| but can they survive the combined impact of local disturbances and global warming? Now| even another mechanism is threatening the reefs: the increase in atmospheric CO2. 3114,2000,3,4,Biodegradability of new engineered fuels compared to conventional petroleum fuels and alternative fuels in current use,Concern with environmental issues such as global climate change has stimulated research into the development of more environmentally friendly technologies and energy sources. One critical area of our economy is liquid transportation fuels. This article presents the results of the biodegradability potential of newly developed engineered fuels and compares the results to the biodegradability of conventional fuels and alternative fuels in current use. Biodegradability potential was determined under both aerobic and anaerobic conditions. Fuels that have a high degree of components derived from renewable sources proved to have a higher degradability potential than those composed of petroleum components.
3144,2000,3,4,Bioenergy in the United States: progress and possibilities,Concerns about global climate change and air quality have increased interest in biomass and other energy sources that are potentially CO(z)-neutral and less polluting. Large-scale bioenergy development could indeed bring significant ecological benefits - or equally significant damage - depending on the specific paths taken. In particular| the land requirements for biomass production are potentially immense. Various entities in the United States have performed research; prepared cost-supply assessments| environmental impact assessments| life cycle analyses and externality impact assessments; and engaged in demonstration and development regarding biomass crops and other potential biomass energy feedstocks. These efforts have focused on various biomass wastes| forest management issues| and biomass crops| including both perennial herbaceous crops and fast-growing woody crops. Simultaneously| several regional and national groups of bioenergy stakeholders have issued consensus recommendations and guidelines for sustainable bioenergy development. It is a consistent conclusion from these efforts that displacing annual agricultural crops with native perennial biomass crops could - in addition to reducing fossil fuel use and ameliorating associated ecological problems also help restore natural ecosystem functions in worked landscapes| and thereby preserve natural biodiversity. Conversely| if forests are managed and harvested more intensively - and/or if biomass crops displace more natural land cover such as forests and wetlands - it is likely that ecosystem functions would be impaired and biodiversity lost. (C) 2000 Elsevier Science Ltd. All rights reserved. 3085,2000,4,3,Bumping against a gas ceiling,The adoption of physical thresholds as a ceiling for permitted climate change sidesteps contentious issues such as: policy cost| impact valuation| discounting and equity. In this paper I offer some reflections on the concept of tolerable climate change. I also use an integrated climate assessment model (ICAM-3) to demonstrate how uncertainties in our understanding of socioeconomic and earth systems reduce the probability of success in keeping climate change within a pre-defined tolerable range. Finally| I explore the implications of socioeconomic thresholds for welfare loss in pursuit of a climate policy (e.g.| tax rebellions). Crossing such regional socioeconomic thresholds will lead to local failures to pursue climate change mitigation policies - increasing the probability of straying beyond the tolerable window of global climate change. Given various uncertainties and the dynamics of the socioeconomic and the earth systems| the odds of success in staying within a climate change window of Delta T less than or equal to 2 degrees C| and Delta T/yr less than or equal to 0.015 degrees C are estimated to be no higher than 25% over the next century. A risk-risk tradeoff approach appears to hold promise| but while adoption of a larger window of tolerance increases the probability of success| it also opens the window specification criteria to contention. 5325,2000,2,4,Can ozone depletion and global warming interact to produce rapid climate change?,The atmosphere displays modes of variability whose structures exhibit a strong longitudinally symmetric (annular) component that extends from the surface to the stratosphere in middle and high latitudes of both hemispheres. In the past 30 years| these modes have exhibited trends that seem larger than their natural background variability| and may be related to human influences on stratospheric ozone and/or atmospheric greenhouse gas concentrations. The pattern of climate trends during the past few decades is marked by rapid cooling and ozone depletion in the polar lower stratosphere of both hemispheres| coupled with an increasing strength of the wintertime westerly polar vortex and a poleward shift of the westerly wind belt at the earth's surface. Annular modes of variability are fundamentally a result of internal dynamical feedbacks within the climate system| and as such can show a large response to rather modest external forcing. The dynamics and thermodynamics of these modes are such that strong synergistic interactions between stratospheric ozone depletion and greenhouse warming are possible. These interactions may be responsible for the pronounced changes in tropospheric and stratospheric climate observed during the past few decades. If these trends continue| they could have important implications for the climate of the 21st century. 5239,2000,4,2,Carbon dioxide gas sensing with the combination of divalent magnesium ion and oxide ion conducting solid electrolytes,The main gas species causing the global warming of the earth is carbon dioxide (CO2) and the human race must seek for the solution to suppress the continuous increase crisis of the CO2 concentration in the atmosphere. Here| two types of solid electrolytes were rigidly selected from their thermodynamic stability and reasonably high ionic conducting properties point of view to create the CO2 practical sensing performance. 3119,2000,4,4,Carbon metabolism of the terrestrial biosphere: A multitechnique approach for improved understanding,Understanding terrestrial carbon metabolism is critical because terrestrial ecosystems play a major role in the global carbon cycle. Furthermore| humans have severely disrupted the carbon cycle in ways that will alter the climate system and directly affect terrestrial metabolism. Changes in terrestrial metabolism may well be as important an indicator of global change as the changing temperature signal. Improving our understanding of the carbon cycle at various spatial and temporal scales will require the integration of multiple| complementary and independent methods that are used by different research communities. Tools such as air sampling networks| inverse numerical methods| and satellite data (top-down approaches) allow us to study the strength and location of the global- and continental-scale carbon sources and sinks. Bottom-up studies provide estimates of carbon fluxes at finer spatial scales and examine the mechanisms that control fluxes at the ecosystem| landscape| and regional scales. Bottom-up approaches include comparative and process studies (for example| ecosystem manipulative experiments) that provide the necessary mechanistic information to develop and validate terrestrial biospheric models. An iteration and reiteration of top-down and bottom-up approaches will be necessary to help constrain measurements at various scales. We propose a major international effort to coordinate and lead research programs of global scope of the carbon cycle. 3077,2000,3,3,Carbon sinks in the Kyoto Protocol - Potential relevance for US forests,The international agreement known as the Kyoto Protocol seeks to reduce the atmospheric concentration of greenhouse gases to mitigate the threat of global climate change. It contains provisions for including carbon stock changes from forests and land-use change to meet nations' greenhouse gas commitments| but the terms under which forest-related carbon stock changes are included are open to interpretation. Critical questions include how much of the carbon currently being sequestered by US forests might qualify| and what forest management activities will be included. 5238,2000,5,1,Causes of climate change over the past 1000 years,Recent reconstructions of Northern Hemisphere temperatures and climate forcing over the past 1000 years allow the warming of the 20th century to be placed within a historical context and various mechanisms of climate change to be tested. Comparisons of observations with simulations from an energy balance climate model indicate that as much as 41 to 64% of preanthropogenic (pre-1850) decadal-scale temperature variations was due to changes in solar irradiance and volcanism. Removal of the forced response from reconstructed temperature time series yields residuals that show similar variability to those of control runs of coupled models| thereby lending support to the models' value as estimates of low-frequency variability in the climate system. Removal of all forcing except greenhouse gases from the similar to 1000-year time series results in a residual with a very large late-20th-century warming that closely agrees with the response predicted from greenhouse gas forcing. The combination of a unique level of temperature increase in the late 20th century and improved constraints on the role of natural variability provides further evidence that the greenhouse effect has already established itself above the level of natural variability in the climate system. A 21st-century global warming projection far exceeds the natural variability of the past 1000 years and is greater than the best estimate of global temperature change for the last interglacial. 3107,2000,2,4,Cautionary tales: Adaptation and the global poor,Many who study global change| particularly from industrialized countries| are optimistic about the capacity of agriculture to successfully adapt to climate change. This optimism is based on historic trends in yield increases| on the spread of cropping systems far beyond their traditional agroecological boundaries| and the inherent flexibility of systems of international trade. Analysis of the success (or in rare cases| failure) of adaptation is by analogy-either to analogous socioeconomic or technological change or to short term environmental change. Such studies have been limited to industrialized countries. This paper uses five analogs from developing countries to examine potential adaptation to global climate change by poor people. Two are studies of comparative developing country responses to drought| flood| and tropical cyclone and to the Sahelian droughts of the 1970s and 80s that illustrate adaptations to climate and weather events:. Two address food production and rapid population growth in South Asia and Africa. Three types of adaptive social costs are considered: the direct costs of adaptation| the costs of adapting to the adaptations| and the costs of failing to adapt. A final analog reviews 30 village-level studies for the role that these social costs of adaptation play in perpetuating poverty and environmental degradation. 3066,2000,4,4,Challenges of measuring forest floor organic matter dynamics: Repeated measures from a chronosequence,Accurate estimates of the retention of carbon in forest soils following forest disturbances are essential to predictions of global carbon cycling. The belief that 50% of soil carbon is lost in the first 20 years after clearcutting is largely based on a chronosequence study of forest floors in New Hampshire northern hardwoods (Covington| 1981). We resampled forest floors in 13 stands in a similar chronosequence after an interval of 15 years. The three youngest stands| which were predicted to lose organic matter over this time| did not exhibit the 40-50% losses predicted by the original chronosequence. The oldest stands had about twice as much organic mass in the forest floor as those cut recently| but this pattern could be explained equally well by historical changes in the nature of forest harvest as by the age of the stands. For example| mechanized logging probably causes more mechanical disturbance to the forest floor than horse logging| burying more organic matter into the mineral soil. Markets for forest products and the intensity of harvest removals have also changed over time| possibly contributing to lower organic matter in the forest floor in young stands. In any chronosequence study| effects of change in the nature of the treatment over time can easily be misinterpreted as change with time since treatment; Repeated sampling of the chronosequence provides controls for some of these effects. Ln the case of forest floor organic matter| however| high spatial variation makes it difficult to distinguish whether the observed variation is more likely due to changes in treatment over time or to differences in time since treatment. Because of the large amounts of carbon involved| small changes in rates of soil organic matter storage may be quite important in global climate change| but they will remain difficult to detect| even with very intensive sampling. (C) 2000 Elsevier Science B.V. All rights reserved. 5320,2000,3,4,Changes in carbon storage in fallow forests in the tropical lowlands of Borneo,The range of CO2 emissions to the atmosphere from tropical land-use change has long been debated. A major source of uncertainty is attributable to the fluxes of CO2 due to changes in tropical land use. For example| estimate is different depending on whether the biomass or carbon content of tropical forests is totally lost by burning or recovered by regrowth. To estimate CO2 absorption by fallow forests after shifting cultivation| we investigated the floristic composition and measured the biomass of fallow forests in East Kalimantan| Indonesia. Above-ground biomass of fallow forests were 8-10 t/ha at one-year-old stands and 45-56 t/ha at 10-12-year-old stands| regardless of the floristic composition. It seems reasonable to suppose that 7.4% of carbon released to the atmosphere by tropical rain forest destruction is reabsorbed and stored by fallow forests in Indonesia. If this is a universal trend in other tropical forests| a significant amount of CO2 is reabsorbed in fallow forests. We consider that fallow forests like the one studied here are substantial carbon sinks and help to offset the effects of anthropogenic CO2 emissions. (C) 2000 Elsevier Science B.V. All rights reserved. 5243,2000,5,4,Changes in dryness/wetness in China during the last 529 years,Historical written records of weather conditions that affect agriculture and living conditions in China can serve as a proxy for instrumental observations of the relative wetness and dryness| or precipitation amounts| for periods of time dating back to at least AD 1470. The dryness/wetness index (DW) data at 100 selected sites and at a subset of 25 sites with entirely continuous data indicate that during the growing season the number of sites with dryness increased rapidly in the 20th century| in contrast to a gradual increase and levelling off of wetness since the 18th century. Dry conditions existed mostly in northeastern China in the 16th and 17th centuries. In the 20th century| dryness prevailed in most areas in China| and the chance of occurrence at each site increased. Wet conditions have expanded from east coastal areas to inland since the 19th century. As a result of increased dryness and wetness| the number of sites experiencing normal precipitation conditions has dropped dramatically. The number of sites with extreme dryness/wetness has also increased during the 20th century| and the spatial distribution of the sites with a large chance of extreme dryness/wetness has also changed. The frequent occurrences in dryness/wetness as well as in extremes in the 20th century seem indicative of an abnormality in climate on a large scale. Spectral analyses of the DW data has revealed that cycles in dryness/wetness and their extremes have existed with periods on relatively short time scales as well as on the long time scales. The possible existence of a century-scale cycle suggests that caution should be used in relating variations in rainfall conditions to global warming. Copyright (C) 2000 Royal Meteorological Society. 3095,2000,4,4,Characterizing regional economic impacts and responses to climate change,While much progress has been made in recent years in modeling the impacts of greenhouse gases on global climate and impacts of global climate change on regional climates| much less progress has been made in modeling economic impacts and responses to climate change| particularly at a regional level. This lack of progress is due| in large part| to the fact that there is no generally accepted framework for characterizing the regional economic impacts of| and responses to| climate change. The objective of this paper is to make a start at such a framework. We divide economic impacts at a regional level into four broad categories: direct impacts on production of market goods and services; direct impacts on production of nonmarket goods and services; indirect impacts on other economic sectors within the region; and indirect impacts operating through other regions and countries. We go on to consider two modeling frameworks for responses to climate change: static| in which regional capital stocks| technologies| and public and private institutions are exogenous; and dynamic| in which these variables are endogenous. Dynamic responses in capital stocks| technologies| and institutions are likely to be the most important adaptations to climate change and its effects on ecosystems| but also the least well understood at the present time. (C) 2000 Elsevier Science B.V. All rights reserved. 5295,2000,3,3,Chlorofluorocarbons substitution in rigid polyurethane foams,The substitution of chlorofluorocarbons (CFC) has represented a major challenge not only for the fluid producers but also for the final users who relied on these molecules. Rigid polyurethane foams have been profoundly affected by this change. This paper will especially address the consequence of the CFC-11 substitution on the formulation itself of rigid polyurethane foams. In a second part| the overall impact on the environment of current and future substitutes will be reviewed : contributions to the global warming and to the creation of tropospheric ozone. 3116,2000,2,4,Climate change and climate variability: Adaptations to reduce adverse health impacts,Global climate change is likely to have a range of consequences for human health as a result of disturbance or weakening of the biosphere's natural or human-managed Life support systems. The full range of potential human health impacts of global climate change is diverse and would be distributed differentially spatially and over time. Changes in the mortality toll of heatwaves and changes in the distribution of vector-borne infectious diseases may occur early. The public health consequences of sea level rise and of regional changes in agricultural productivity may not occur (or become apparent) for several decades. Vulnerability is a measure of both sensitivity to climate change and the ability to adapt in anticipation of| or in response to| its impacts. The basic modes of adaptation to climate-induced health hazards are biological| behavioural and social. Adaptation can be undertaken at the individual| community and whole-population levels. Adaptive strategies should not introduce new health hazards. Enhancement of the acknowledged public health infrastructure and intervention programmes is essential to reduce vulnerability to the health impacts of climate change. In the longer-term| fundamental improvements in the social and material conditions of life and in the reduction of inequalities within and between populations are required for sustained reduction in vulnerability to environmental health hazards. 5142,2000,2,4,Climate change and impacts of boreal forest insects,The circum-polar boreal forest has played an important role in the wealth of northern nations since the 15th century. Its natural resources spurred strategic geopolitical developments beginning in the 16th century but intense development of the boreal forest is largely limited to the 20th century. Insects cause considerable loss of wood that has an adverse effect on the balance of carbon sequestered by forests. Current understanding of processes that lead to stand-replacing outbreaks in three insect species is reviewed in this paper. Many of these processes depend on climate either directly| such as reduced survival with extreme weather events| or indirectly| mainly through effects on the host trees. In the boreal zone of Canada| pest-caused timber losses may be as much as 1.3-2.0 times the mean annual depletions due to fires. Pests are thus major| but consistently overlooked forest ecosystem components that have manifold consequences to the structure and functions of future forests. Global change will have demonstrable changes in the frequency and intensity of pest outbreaks| particularly at the margins of host ranges. The consequent shunting of carbon back to the atmosphere rather than to sequestration in forests as biomass is thought to have positive feedback to global warming. Whereas significant progress has been made in developing carbon budget models for the boreal forests of Canada| enormous problems remain in incorporating pest effects in these models. These problems have their origins in the nature of interactions among pests with forest productivity| and problems with scaling. The common problems of verification and validation of model results are particularly troublesome in projecting future forest productivity. The interaction of insects with fires must be accounted for if realistic carbon sequestration forecasts in a warming climate are to be made| These problems make assessments of mitigation and adaptation of pest management alternatives difficult to evaluate at present. Nevertheless| the impacts of stand-replacing insect population outbreaks is important in formulating future resource management policy. Crown Copyright (C) 2000 Published by Elsevier Science B.V. All rights reserved. 3104,2000,2,4,Climate change and resource management in the Columbia River basin,Scenarios of global climate change were examined to see what impacts they might have on transboundary water management in the Columbia River basin. Scenario changes in natural streamflow were estimated using a basin hydrology model. These scenarios tended to show earlier seasonal peaks| with possible reductions in total annual flow and lower minimum flows. Impacts and adaptation responses to the natural streamflow scenarios were determined through two exercises: (a) estimations of system reliability using a reservoir model with performance measures and (b) interviews with water managers and other stakeholders in the Canadian portion of the basin. Results from the two exercises were similar| suggesting a tendency towards reduced reliability to meet objectives for power production| fisheries| and agriculture. Reliability to meet flood control objectives would be relatively unchanged in some scenarios but reduced in others. This exercise suggests that despite the high level of development and management in the Columbia| vulnerabilities would still exist| and impacts could still occur in scenarios of natural streamflow changes caused by global climate change. Many of these would be indirect| reflecting the complex relationship between the region and its climate. 3109,2000,2,4,Climate change impacts on the hydrology and productivity of a pine plantation,There are increasing concerns in the forestry community about global climate change and variability associated with elevated atmospheric CO2 Changes in precipitation and increases in air temperature could impose additional stress on forests during the next century. For a study site in Carteret County| North Carolina| the General Circulation Model| HADCM2| predicts that by the year 2099| maximum air temperature will increase 1.6 to 1.9 degrees C| minimum temperature will increase 2.5 to 2.8 degrees C| and precipitation will increase 0 to 10 percent compared to the mid-1990s. These changes vary from season to season. We utilized a forest ecosystem process model| PnET-II| for studying the potential effects of climate change on drainage outflow| evapotranspiration| leaf area index (LAI) and forest Net Primary Productivity (NPP). This model was first validated with long term drainage and LAI data collected at a 25-ha mature loblolly pine (Pinus taeda. L.) experimental watershed located in the North Carolina lower coastal plain. The site is flat with poorly drained soils and high groundwater table. Therefore| a high field capacity of 20 cm was used in the simulation to account for the topographic effects. This modeling study suggested that future climate change would cause a significant increase of drainage (6 percent) and forest productivity (2.5 percent). Future studies should consider the biological feedback (i.e.| stomata conductance and water use efficiency) to air temperature change. 5187,2000,2,3,Climate change impacts on urban flooding,This paper estimates changes in the potential damage of flood events caused by increases of CO2 concentration in the atmosphere. It is presented in two parts: 1. the modelling of flood frequency and magnitude under global warming and associated rainfall intensities and 2. the use of greenhouse flood data to assess changes in the vulnerability of flood prone urban areas| expressing these in terms of direct losses. Three case studies were selected: the Hawkesbury-Nepean corridor| the Queanbeyan and Upper Parramatta Rivers. All three catchments are located in southeastern Australia| near Sydney and Canberra. These were chosen because each had detailed building data bases available and the localities are situated on rivers that vary in catchment size and characteristics. All fall within a region that will experience similar climate change under the available greenhouse scenarios. The GCMs' slab model scenarios of climate change in 2030 and 2070 will cause only minor changes to urban flood damage but the double CO2 scenarios estimated using the Stochastic Weather Generator technique will lead to significant increases in building damage. For all the case studies| the hydrological modelling indicates that there will be increases in the magnitude and frequency of flood events under the double CO2 conditions although these vary from place to place. However| the overall pattern of change is that for the Upper Parramatta River the 1 in 100-year flood under current conditions becomes the 1 in 44-year event| the 1 in 35-year flood for the Hawkesbury-Nepean and the 1 in 10 for Queanbeyan and Canberra. This indicates the importance of using rainfall-runoff modelling in order to estimate changes in flood frequencies in catchments with different physical characteristics. 5270,2000,2,4,Climate change in the semiarid prairie of southwestern Saskatchewan: Temperature| precipitation| wind| and incoming solar energy,Long-term weather data were analyzed to study annual as well as seasonal climate change within an approximately 15 000-km(2) area in the semiarid prairie near Swift Current| SK. The climate of the study region has changed over the past 50 yr. Annually| average maximum (T-mx) and minimum (T-mn) air temperatures have increased - rainfall amounts and the number of rainfall events (greater than or equal to 0.5 mm) have increased since the late 1960s-early 1970s; incoming solar energy has decreased| and wind speed has decreased since the early 1970s. Seasonally| for January through April (JFMA)| both T-mx and T-mn have increased| the number of rainfall events has increased since the early 1970s| snowfall amounts and the number of snowfall events (greater than or equal to 0.5 cm) have decreased; the number of precipitation events (greater than or equal to 0.5 mm) has decreased| incoming solar energy has decreased| and wind speed has decreased since the early 1970s. For May through August (MJJA)| T-mn has increased| incoming solar energy has decreased| and wind speed has decreased since the mid-1970s. For September through December (SOM))| the number of rainfall events has increased since the early 1970s and wind speed has decreased. Since 1950| JFMA has become drier and| relative to JFMA| SOND has become wetter. Generally| JFMA has experienced the largest change in climate| whereas SOND has experienced the least climate change. Precipitation amounts and events were negatively correlated with increasing T-mx| suggesting a future decrease in precipitation amounts for southwestern Saskatchewan if global warming continues. 5292,2000,2,3,Climate change: Potential impacts and interactions in wetlands of the United States,Wetlands exist in a transition zone between aquatic and terrestrial environments which can be altered by subtle changes in hydrology. Twentieth century climate records show that the United States is generally experiencing a trend towards a wetter| warmer climate; some climate models suggest that this trend will continue and possibly intensify over the next 100 years. Wetlands that are most likely to be affected by these and other potential changes (e.g.| sea-level rise) associated with atmospheric carbon enrichment include permafrost wetlands| coastal and estuarine wetlands| peatlands| alpine wetlands| and prairie pothole wetlands. Potential impacts range from changes in community structure to changes in ecological function| and from extirpation to enhancement. Wetlands (particularly boreal peatlands) play an important role in the global carbon cycle| generally sequestering carbon in the form of biomass| methane| dissolved organic material and organic sediment. Wetlands that are drained or partially dried can become a net source of methane and carbon dioxide to the atmosphere| serving as a positive biotic feedback to global warming. Policy options for minimizing the adverse impacts of climate change on wetland ecosystems include the reduction of current anthropogenic stresses| allowing for inland migration of coastal wetlands as sea-level rises| active management to preserve wetland hydrology| and a wide range of other management and restoration options. 5287,2000,2,4,Climate variability and size-structured interactions among juvenile fish along a lake-stream gradient,We examine the influence of biological interactions and interannual variation in climate an the size structure and trophic interactions between age-0 largemouth bass (Micropterus salmoides) and age-0 creek chubs (Semotilus atromaculatus) along a lake-stream gradient in northern Minnesota| USA. Considerable year-to-year variation in temperature and precipitation occurred during the 10-yr study (1983-1992)| with most extreme hut-dry conditions in 1988 during a 3-yr drought. Decreased stream temperature and reduced variation in temperature: occurred downstream from the lake outlet because of increased groundwater inputs. Age-0 bass were captured in the stream in each of the eight years sampled| but bass abundance peaked in downstream reaches in 1988| concurrent with a large increase in the downstream density of age-0 chubs. Median length ratio of bass to chubs increased greatly in the 1988 drought year. The shift in relative length of bass and chubs during the drought was because chub length decreased in downstream areas| and bass shifted from feeding an invertebrates to feeding on chubs in downstream but not in upstream reaches. Comparison of bass and chub growth in the presence and absence of interspecific competition for invertebrate resources in an experimental stream revealed higher growth rates for chubs than for bass and little interspecific competition. Experiments in the artificial stream indicated that the presence or absence of chubs susceptible to bass predation had only marginal effects on bass survival| but growth rates of bass were substantially higher if chubs susceptible to predation were present. Only when chubs were present was the growth of individual bass dependent strongly on size| and this led to rapid divergence in the size distribution of bass in chubs vs. no-chubs treatments. Our results indicate that hot-dry climatic conditions associated with drought have potentially strong effects on size-structured trophic interactions between age-0 fish along lake-stream gradients. Hot-dry climatic conditions alter the spatial distribution of lake fish along temperature gradients in the stream| the reproductive success and synchrony of lake and stream fish development| and the eventual growth of predatory lake species. The response of fish to climatic variation appears to be strongly influenced by their position in the "hydrologic landscape." The most dramatic fish response occurred in stream reaches influenced by groundwater. 5184,2000,5,2,Climatic control of blanket mire development at Kentra Moss| north-west Scotland,1 Four peat cores were collected from Kentra Moss| north-west Scotland| and analysed for botanical macrofossils and peat humification. The pollen record was used as a template for the identification of synchronous levels between cores. 2 A non-random pattern of change in bryophyte macrofossils and humification was simultaneous between all four cores. Stratigraphic changes occurred independently of human land-use and were best interpreted as palaeoclimatic events. Remains of Racomitrium lanuginosum and Sphagnum papillosum| in conjunction with changes in peat humification| provided the clearest indication of past increases in climatic wetness ('wetshifts') to impact upon mire hydrology and ecology. 3 Eight wetshifts were identified and radiocarbon-dated| beginning at c. 3250| 2550| 2150| 1400| 1150| 875| 600 and 325 calibrated years BP (cal. BP). Seven of these wetshifts match closely with palaeoclimatic events from a range of mires previously examined in Britain and Ireland. We suggest that blanket mires may provide the best source of decade- to century-scale palaeoclimatic information in oceanic north-west Europe. 4 The proxy-climatic evidence indicates that: (i) the extinction of Sphagnum imbricatum at Kentra Moss (at c. 1400 cal. BP) was caused by an increase in climatic and mire surface wetness| when it was replaced first by Racomitrium lanuginosum and then by Sphagnum papillosum; and (ii) that increased climatic wetness and human land-use were responsible for the shift from an early minerotrophic peatland to ombrotrophic blanket mire at c. 4070 cal. BP. 5 Given the evidence for a prevailing climatic effect on the development of Kentra Moss| the effect of human-induced global warming on Britain's blanket mire resource will probably be significant. British blanket mires have international conservation status| and future changes in their ecology will challenge conservationists| academics and politicians. 3088,2000,2,4,Climatic variation and simulated patterns in seedling establishment of two dominant grasses at a semi-arid-arid grassland ecotone,The objective of this study was to predict the effects of climatic variation at multiple temporal frequencies on seedling establishment by two congeneric C-4 perennial grasses (Bouteloua gracilis and B. eriopoda) at the ecotone between shortgrass steppe grassland and Chihuahuan desert grassland in central New Mexico| USA. The approach was to use a daily time-step simulation model to determine the occurrence of a recruitment event in each year based upon the amount and timing of soil water required for establishment. Historical weather data were used to predict effects of seasonal and interdecadal variation in climate on establishment. A sensitivity analysis was used to predict effects of directional climate change on establishment. Bouteloua gracilis had a broad pattern of simulated establishment from May through September that included periods with high year-to-year variation in precipitation. B. eriopoda establishment events occurred primarily in July when precipitation amounts were most reliable. Climatic conditions from 1949 through 1968 were more favorable for B. eriopoda establishment compared to the cooler| wetter conditions from 1969 through 1988 that favored B. gracilis. Establishment of B. eriopoda was lowest in El Nino years whereas B. gracilis establishment was highest in La Nina years. Establishment of B. gracilis was most sensitive to temperature when precipitation was higher than current amounts. The greatest response to temperature by B. eriopoda for all precipitation amounts occurred at cooler temperatures than found currently. These results indicate that climatic variation at multiple frequencies has differential effects on seedling establishment for these two perennial grasses| and may account at least in part for patterns in dominance at this biome transition zone. 3060,2000,2,4,Climatic warming in the Tibetan Plateau during recent decades,Adequate knowledge of climatic change over the Tibetan Plateau (TP) with an average elevation of more than 4000 m above sea level (a.s.1.) has been insufficient for a long time owing to the lack of sufficient observational data. In the present study| monthly surface air temperature data were collected from almost every meteorological station on the TP since their establishment. There are 97 stations located above 2000 m a.s.1. on the TP; the longest records at five stations began before the 1930s| but most records date from the mid-1950s. Analyses of the temperature series show that the main portion of the TP has experienced statistically significant warming since the mid-1950s| especially in winter| but the recent warming in the central and eastern TP did not reach the level of the 1940s warm period until the late 1990s. Compared with the Northern Hemisphere and the global average| the warming of the TP occurred early. The linear rates of temperature increase over the TP during the period 1955-1996 are about 0.16 degreesC/decade for the annual mean and 0.32 degreesC/decade for the winter mean| which exceed those for the Northern Hemisphere and the same latitudinal zone in the same period. Furthermore| there is also a tendency for the warming trend to increase with the elevation in the TP and its surrounding areas. This suggests that the TP is one of the most sensitive areas to respond to global climate change. Copyright (C) 2000 Royal Meteorological Society. 5328,2000,2,4,Climatological significance of an ice core net-accumulation record at Mt. Qomolangma (Everest),An ice core record at Mt. Qomolangma (Everest) since 1954 reveals a sharp decline in net-accumulation in the 1960s| and the annual net-accumulation during the 1970s to the beginning of the 1990s is only half of that at the end of the 1950s. The decreased net-accumulation is coincident with glacier retreat| which is associated with recent temperature increase in the region that intensified the ablation. Under the background of global warming| such glacier variation trends will aggravate. 5190,2000,3,3,CO2 sequestration at sea by gas-lift system of shallow injection and deep releasing,To mitigate global warming| a system dissolving huge amounts of CO2 gas captured from fossil fuel fired power plants into the ocean with high acceptance by the ocean environment is indispensable. To this aim| we propose a sequestration system of CO2 in the deep ocean. The system is an inverse-J pipeline set in the ocean at a depth of 200-3000 m. In the system| a pumping effect by buoyancy of the dissolving CO2 bubbles is used to transport CO2-rich seawater to great depths. in the present paper| we discuss characteristics and performance of our proposal on the basis of experimental and numerical investigation. in a laboratory-scale experiment (pipe diameter of 25 mm and pipe height of 7.69 m)| we observed over 98% dissolution of injected CO2 gas into tap water. The liquid-phase flow caused by gas-rift effect was strong enough to transport the CO2-rich water including nondissolved tiny bubbles into the deep ocean. Then a numerical simulation based on the experimentally derived models was applied to a system considering 10 MW class power plants. The results showed that our proposal is hopeful for an efficient method of CO2 disposal into the deep ocean. 5144,2000,3,2,Coal gasification system using nuclear heat for ammonia production,Utilization of nuclear energy is an effective way of solving the global warming resulting from CO2 emissions. Thermal energy accounts for more than two thirds of total energy utilization at present and therefore it is significant to extend the utilization of nuclear heat for the effective reduction of CO2 emissions in the world. This paper describes a coal gasification system using HTGR nuclear heat in an ammonia production plant in terms of industrial utilization of the nuclear heat. The system uses the nuclear heat directly in addition to generating electricity. A steam reforming method using a two-stage coal gasifier is employed: it improves the heat utilization efficiency of the secondary helium gas from the: HTGR. Finally| the paper clarifies that the nuclear gasification system can reduce CO2 emissions by about five hundred thousand tons per year from that of a conventional system using fossil fuel. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. 5309,2000,2,4,Coastal-zone biogeochemical dynamics under global warming,The coastal zone| consisting of the continental shelves to a depth of 200 meters| including bays| lagoons| estuaries| and near-shore banks| is an environment that is strongly affected by its biogeochemical and physical interactions with reservoirs in the adjacent domains of land. atmosphere| open ocean. and marine sediments. Because the coastal zone is smaller in volume and areal coverage relative to the open ocean| it traditionally has been studied as an integral part of the global oceans. In tl-lis paper| we show by numerical modeling that it is important to consider the coastal zone as an entity separate from the open ocean in any assessment of future Earth-system response under human perturbation. Model analyses for the early part of the 21st century suggest that the coastal zone plays a significant modifying role in the biogeochemical dynamics of the carbon cycle and the nutrient cycles coupled to it. This role is manifested in changes in primary production| storage| and/or export of organic matter| its remineralization. and calcium carbonate precipitation-all of which determine the state of the coastal zone with respect to exchange of CO(2) with the atmosphere. Under a scenario of future reduced or complete cessation of the thermohaline circulation (THC) of the global oceans| coastal waters become an important sink for atmospheric CO(2)| as opposed to the conditions in the past and present| when coastal waters are believed to be a source of CO(2)| to the atmosphere. Profound changes in coastal-zone primary productivity underscore the important role of phosphorus as a limiting nutrient. In addition| our calculations indicate that the saturation state of coastal waters with respect to carbonate minerals will decline by similar to 15% by the year 2030. Any future slowdown in the THC of the oceans will increase slightly the rate of decline in saturation state. 3071,2000,5,4,Cold rocks| hot sands: In-situ cosmogenic applications in Australia at ANTARES,The ANTARES AMS facility at ANSTO is conducting a comprehensive program in the application of in-situ cosmogenic radionuclides based on strong university collaborations in the earth sciences. The program targets two major objectives: (1) to determine and improve the Quaternary glacial chronology of the Southern Hemisphere in support of global climate change studies; (2) to characterise the processes of surface weathering and landscape evolution in semi-arid regions of the Australian continent. An overview of the program is presented with preliminary results from the first phase of these studies. (C) 2000 Elsevier Science B|V| All rights reserved. 5199,2000,2,4,Comparing species temperature response curves: population density versus second-hand data,Descriptions of individual species responses to temperature are required in order to assess the impact of future global warming. The response of Rhododendrom arboreum to estimated mean annual temperature was investigated in the Himalayas using General Additive Models (GAM) and Generalized Linear Models (GLM). The aim was to evaluate the consistency between the response in population density along elevation gradients versus response curves based on elevation data from herbarium specimens and vegetation surveys. The comparison was made with respect to (1) estimated temperature at the point of maximum response and (2) the shape of the response curves i.e. symmetric vs skewed. All data indicate a single optimum between 12.3 and 10.8 degreesC. The difference is only 0.4 degreesC between the optimum estimated from localities of herbarium specimens (frequency) and the population density data. The difference is larger (0.7 degreesC) when the vegetation survey data are combined with the data from the herbarium specimens. However| the differences are small when the uncertainties in temperature estimation are taken into consideration. The response curves based on herbarium specimens and vegetation survey data (frequencies) are symmetric. A sigmoid response curve was estimated from herbarium specimens (binomial data). The population density along the elevation gradients was| to some extent| asymmetric. This may reflect the underlying biological structure| but sampling bias and the numerical analyses may also influence the results. 3096,2000,3,4,Conservation practices in US agriculture and their implication for global climate change,Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This| in turn| will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual| site-specific conservation practices on changes in soil organic carbon. There is a general absence| however| of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage| the Conservation Reserve Program and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices| it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was approximately 12200000 metric tons. By 2008| there will be an increase of approximately 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration| there are a number of policy options that can be pursued. These include education and technical assistance| financial assistance| research and development| land retirement and regulation and taxes. (C) 2000 Elsevier Science B.V. All rights reserved. 5353,2000,3,4,Considering the next generation of nuclear power plants,Nuclear power will be needed for future energy demands| which are expected to grow at different rates around the world. The opportunities for building new nuclear power plants around the world will be depend on need| energy demand growth| and issues related to global warming and climate change. However| four major barriers exist for the expansion of nuclear power: economics| proliferation| safety| and waste. These issues must be addressed in the ongoing research and development of nuclear energy technology and applications. The evolution of nuclear power plant technology is presented as four distinct design generations: (1) prototypes| (2) current operating plants| (3) advanced light water reactor technology| and (4) revolutionary design concepts (i.e.| Generation IV) that are now under development. The U.S. DOE Nuclear Energy Research Initiative (NERI) program is focused on the research and development of Generation IV designs that are safe| economic| proliferation-resistant| and will address current waste issues. NERI provides grants for independently peer-reviewed proposals from universities| national laboratories and industry for advanced nuclear research and development. Several NERI projects awarded in 1999 are described in terms of how they remove barriers to nuclear power plant expansion. Another DOE effort| the Accelerator Transmutation of Waste program| will seek to reduce and ameliorate civilian reactor waste. The Accelerator Transmutation of Waste program will involve a six-year science-based research plan to define key technical issues. Finally| the need for international collaboration is stressed for fourth-generation nuclear power technology development. Published by Elsevier Science Ltd. 5298,2000,3,4,Consistent sets of atmospheric lifetimes and radiative forcings on climate for CFC replacements: HCFCs and HFCs,Recognition of deleterious effects of chlorine and bromine on ozone and climate over the last several decades has resulted in international accords to halt the production of chlorine-containing chlorofluorocarbons (CFCs) and bromine-containing halons. It is well recognized| however| that these chemicals have had important uses to society| particularly as refrigerants| as solvents| as plastic blowing agents| as fire retardants and as aerosol propellants. This has led to an extensive search far substitute chemicals with appropriate properties to be used in place of the CFCs and halons. The purpose of this study is to evaluate in a consistent manner the atmospheric lifetime and radiative forcing on climate for a number of replacement compounds. The unique aspect of this study is its attempt to resolve inconsistencies in previous evaluations of atmospheric lifetimes and radiative forcings for these compounds by adopting a uniform approach. Using the latest version of our two-dimensional chemical-radiative-transport model of the global atmosphere| we have determined the atmospheric lifetimes of 28 hydrohalocarbons (HCFCs and HFCs). Through the comparison of the model-calculated lifetimes with lifetimes derived using a simple scaling method| our study adds to earlier findings that consideration of stratospheric losses is important in determining the lifetimes of gases| Discrepancies were found in the reported lifetimes of several replacement compounds reported in the international assessment of stratospheric ozone published by the World Meteorological Organization [Granier et al.| 1999] and have been resolved. We have also derived the adjusted and instantaneous radiative forcings for CFC-11 and 20 other halocarbons using our radiative transfer model. The sensitivity of radiative forcings to the vertical distribution of these gases is investigated in this study and is shown to be significant. The difference in the global radiative forcing arising from the assumption of a constant vertical profile for these gases is found to range from 0 to 36%| with higher difference for short-lived gases. Global Warming Potentials (GWPs) for the compounds are determined using the lifetimes and radiative forcings evaluated in this study and are found to differ from values reported by Granier et al. [1999] owing to the differences in our calculated radiative forcings and lifetimes. 3105,2000,2,4,Contribution of agrometeorology to the simulation of crop production and its applications,Weather has a significant impact on crop growth and development. This paper presents an overview of crop modeling and applications of crop models| and the significance of weather related to these applications. To account for the impact of weather and climate variability on crop production. agrometeorological variables are one of the key inputs required for the operation of crop simulation models. These include maximum and minimum air temperature| total solar radiation| and total rainfall. Most models use daily data as input| because variables at a smaller time scale are usually unavailable for most locations. It is important to define standard file formats for weather and other input data; this will expand the applicability of weather data by different models. Issues related to missing variables and data| as well as locations for which no data are available| need to be addressed for model applications| as it can affect the accuracy of the simulations. Weather generators can be used to stochastically generate daily data when data are missing or long-term historical data are unavailable. However| the use of observed weather data for model input will provide more precise crop yield simulations| especially for tropical regions. Many of the crop models have been applied towards strategic and tactical management decision making as well as yield forecasting. The predicted variability of crop yield and related variables as well as natural resource use is mainly due to the short- and long-term variation of weather and climate conditions. The results produced by the models can be used to make appropriate management decisions and to provide farmers and others with alternative options for their farming system. The crop models have been used extensively to study the impact of climate change on agricultural production and food security. Recently| they have also been applied towards the impact of climate variability and the effect of El Nino/Southern Oscillation (ENSO) on agricultural production and food security. It is expected that| with the increased availability of computers| the use of crop models by farmers and consultants as well as policy and decision makers will increase. Weather data in the form of historical data or observations made during the current growing season| and short-| medium-| and long-term weather forecasts will play a critical role in these applications. (C) 2000 Elsevier Science B.V. All rights reserved. 3093,2000,4,3,Contribution of carbonate rock weathering to the atmospheric CO2 sink,To accurately predict future CO2 levels in the atmosphere| which is crucial in predicting global climate change| the sources and sinks of the atmosphere CO2 and their change over time must be determined. In this paper| some typical cases are examined using published and unpublished data. Firstly| the sensitivity of carbonate rock weathering (including the effects by both dissolution and reprecipitation of carbonate) to the change of soil CO2 and runoff will be discussed| and then the net amount of CO2 removed from the atmosphere in the carbonate rock areas of mainland China and the world will be determined by the hydrochem-discharge and carbonate-rock-tablet methods| to obtain an estimate of the contribution of carbonate rock weathering to the atmospheric CO2 sink. These contributions are about 0.018 billion metric tons of carbon/a and 0.11 billion metric tons of carbon/a for China and the world| respectively. Further| by the DBL (Diffusion Boundary Layer)-model calculation| the potential CO2 sink by carbonate rock dissolution is estimated to be 0.41 billion metric tons of carbon/a for the world. Therefore| the potential CO2 source by carbonate reprecipitation is 0.3 billion metric tons of carbon/a. 5213,2000,3,3,Cooling down hot air: a global CGE analysis of post-Kyoto carbon abatement strategies,The Kyoto Protocol marks a break through in global warming mitigation policies as it sets legally binding emissions targets for major emitting regions. However| realization of the Protocol depends on the clarification of several issues| one of which is the permissible scope of international emissions trading between signatory countries. Unrestricted trade produces hot air when signatory countries| whose Kyoto targets are well above their business as usual emissions| trade in larger amounts of "abundant" emission rights. Concerns on hot air motivated proposals for caps on emissions trading by the EU. These caps are strictly refused by the USA and other non-European industrialized countries who want to exploit the full efficiency gains from trade. In this paper we show that there are "cooling down" strategies which can reconcile both positions. International permit trade provides enough efficiency gains to make all signatory countries better off than they would be without permit trade while mitigating hot air. In other words| part of the efficiency gains from free trade could be used to pay for higher abatement targets of signatory countries which assure the same environmental effectiveness as compared to strictly domestic action or restricted permit trade. (C) 2000 Elsevier Science Ltd. All rights reserved. JEL classification: Q2; Q4; D58. 3073,2000,2,2,Coral bleaching and global climate change: Scientitic findings and policy recommendations,In 1998| tropical sea surface temperatures were the highest on record| topping off a 50-year trend for some tropical oceans. In the same year| coral reefs around the world suffered the most extensive and severe bleaching (loss of symbiotic algae) and subsequent mortality on record. These events may not be attributable to local stressors or natural variability alone but were likely induced by nit underlying global phenomenon. It is probable that anthropogenic global warming has contributed to the extensive coral blenching that has occurred simultaneously throughout the reef regions of the world The geographic extent| increasing frequency| and regional severity of mass bleaching events are an apparent result of a steadily rising baseline of marine temperatures| combined with regionally specific El Nino and La Nina events. The repercussions of the 1998 mass bleaching and mortality events will be far-reaching. Human populations dependent on reef services face losses of marine biodiversity| fisheries| and shoreline protection. Coral bleaching events may become more frequent and severe as the climate continues to warm| exposing coral reefs to an increasingly hostile environment. This global threat to corals compounds the Effects of more localized anthropogenic factors that already place reefs at risk. Significant attention needs to be given to the monitoring of coral reef ecosystems| research on the projected and realized effects of global climate change| and measures to curtail greenhouse gas emissions. Even those reefs with well-enforced legal protection as marine sanctuaries| or those managed for sustainable use| are threatened by global climate change. 5358,2000,2,4,Cyclicity and some characteristics of mass reproduction of Calliptamus italicus L. in southern Russia,Analysis of the reproductive dynamics of Calliptamus italicus during the past 100 years confirmed the dependence of locust invasions on the 11-year cycles of solar activity| which was previously known for other gregarious locusts. Over a considerable part of the species range| the onset of mass reproduction is promoted by a hot and droughty spring and summer. The scale of the outbreak is determined by local conditions in the foci of reproduction. The current global warming is characterized by an unstable| drastically varying climate with a trend toward aridity in many regions. If this trend persists for several decades| we may expect an increase in the periods of C. talicus mass reproduction and in the persistency and extent of damage indicted by locusts on vast Palearctic areas. 3138,2000,4,4,Data assimilation in sea-ice monitoring,The detection of small changes in concentration or thickness in the Arctic or Antarctic ice cover is an important topic in the current global-climate-change debate. Change detection using satellite data alone requires rigorous error analysis for their derived ice products| including inter-satellite validation for long time series. All models of physical processes are only approximations| and the best models of complicated physical processes have errors and uncertainties. A promising approach is data assimilation| combining model| in situ data and satellite remote-sensing data. Sea-ice monitoring from satellite| ice-model estimates| and the potential benefit of combining the two are discussed in some detail. In a case-study we demonstrate how the sea-ice backscatter for the Beaufort Sea region was derived using a backscattering model in combination with an ice model. We conclude that| for data assimilation| the first steps include the use of simple models| moving| with success at this level| to progressively more complex models. We also recommend reconfiguring the current remote-sensing data to include precise time tags with each pixel. For example| the current Special Sensor Microwave Imager data might be reissued in a time-tagged orbital (or gridded) format as opposed to the currently available daily averaged gridded data. Finally error statistics and quality-control information also need to be readily available in a form useful for assimilation. The effectiveness of data-assimilation techniques is directly linked to the availability of data error statistics. 3130,2000,2,3,Dependence of salinity and oxygen concentrations in the Baltic Sea on large-scale atmospheric circulation,The relationship between the low-frequency (annually averaged) salinity and oxygen concentrations in the last 30 yr in the Baltic Sea and the large-scale atmospheric circulation was statistically analyzed. Ii: was found that at these time scales the evolution of salinity and oxygen is guile homogeneous in depth| i.e. deviations from the long-term mean tend to be of the same sign in the upper and deeper layers simultaneously. Moreover| the evolution of the salinity and oxygen concentrations are negatively correlated within each layer: lower than normal salinities tend to be observed simultaneously with higher than normal oxygen concentrations| and vice versa. The statistical analysis seems to indicate that the forcing by the atmospheric circulation may be responsible for this anticorrelation between salinity and oxygen. A stronger meridional sea-level-pressure (SLP) gradient over the North Atlantic| and therefore stronger westerly winds| causes positive rainfall anomalies in the Baltic Sea catchment area and increase run-off giving rise to decreased salinities at all depths. The mechanisms by which a stronger zonal atmospheric circulation enhances the oxygen concentrations may be related either to a weakened stratification through the reduced salinity (at long time scales)| or by stronger or more frequent inflows of North Sea waters (at short time scales). The influence of the atmospheric circulation can explain at these time scales of the order of 60 and 40 % of the variability of these hydrographic variables| respectively. The question of how salinity and oxygen in the Baltic Sea may respond to changes of the atmospheric circulation in a global climate change scenario is also addressed. For this purpose the intensities of the relevant atmospheric circulation patterns in a transient experiment with a coupled atmosphere-ocean general circulation model forced with increasing anthropogenic green house gas concentrations between the years 1860 and 2099 were estimated. In this integration the change of the atmospheric circulation most relevant for salinity and oxygen in the Baltic Sea seems to be an enhancement of the meridional SLP gradient in the North Atlantic. Thus| under the assumption that the statistical relationship between SLP and the hydrographic variables also holds in the future| this trend in the atmospheric circulation would lead to decreased salinity and improved oxygen conditions in the Baltic Sea. 3141,2000,2,4,Desiccation tolerance of three moss species from continental Antarctica,Tolerance of desiccation was examined in three species of moss| Grimmia antarctici Card.| Ceratodon purpureus (Hedw.) Brid. and Bryum pseudotriquetrum (Hedw.) Gaertn.| Meyer et Scherb. collected from two sites of contrasting water availability in the Windmill Islands| continental Antarctica. Physiological tolerance to desiccation was measured using chlorophyll fluorescence in plugs of moss during natural drying in the laboratory. Differences in relative water content| rate of drying and the response of photosynthesis to desiccation were observed among the three species and between sites. Of the three species studied| G. antarctici showed the lowest capacity to sustain photosynthetic processes during desiccation| B. pseudotriquetrum had an intermediate response and showed the greatest plasticity and C. purpureus showed the greatest capacity to sustain photosynthesis during desiccation. These results fit well with the known distribution of the three species with G. antarctici being limited to relatively wet sites| C. purpureus being common in the driest sites and B. pseudotriquetrum showing a wide distribution between these two extremes. Levels of soluble carbohydrates were also measured in these samples following desiccation and these indicate the presence of stachyose| an oligosaccharide known to be important in desiccation tolerance in seeds| in B. pseudotriquetrum. Both gross morphology and carbohydrate content are likely to contribute to differences in desiccation tolerance of the moss species. These results indicate that if the Casey region continues to dry out| as a result of local geological uplifting or global climate change| we would expect to see not only reductions in the moss community but also changes in community composition. G. antarctici is likely to become more limited in distribution as C. purpureus and B. pseudotriquetrum expand into drying areas. 5145,2000,4,2,Detecting a global warming signal in hemispheric temperature series: A structural time series analysis,Non-stationary time series such as global and hemispheric temperatures| greenhouse gas concentrations| solar irradiance| and anthropogenic sulfate aerosols| may contain stochastic trends (the simplest stochastic trend is a random walk) which| due to their unique patterns| can act as a signal of the influence of other variables on the series in question. Two or more series may share a common stochastic trend| which indicates that either one series causes the behavior of the other or that there is a common driving variable. Recent developments in econometrics allow analysts to detect and classify such trends and analyze relationships among series that contain stochastic trends. We apply some univariate autoregression based tests to evaluate the presence of stochastic trends in several time series for temperature and radiative forcing. The temperature and radiative forcing series are found to be of different orders of integration which would cast doubt on the anthropogenic global warming hypothesis. However| these tests can suffer from size distortions when applied to noisy series such as hemispheric temperatures. We| therefore| use multivariate structural time series techniques to decompose Northern and Southern Hemisphere temperatures into stochastic trends and autoregressive noise processes. These results show that there are two independent stochastic trends in the data. We investigate the possible origins of these trends using a regression method. Radiative forcing due to greenhouse gases and solar irradiance can largely explain the common trend. The second trend| which represents the non-scalar non-stationary differences between the hemispheres| reflects radiative forcing due to tropospheric sulfate aerosols. We find similar results when we use the same techniques to analyze temperature data generated by the Hadley Centre GCM SUL experiment. 5277,2000,2,4,Differential response of a sensitive and tolerant sugarbeet line to Cercospora beticola infection and UV-B radiation,Increased ultraviolet-B (UV-B| 280-320 nm) radiation| due to depletion of stratospheric ozone| is an increasing threat to living organisms. Furthermore| increased ground level temperatures as a consequence of global warming may favour development of pathogens| such as Cercospora beticola| that thrive at high temperatures. This study evaluates the effect of combined UV stress and Cercospora leaf-spot disease on young sugarbeet plants (Beta vulgaris L.). An inoculum consisting of twelve European isolates of C| beticola Sacc| was used in the experiments| One Cercospora-sensitive and one Cercospora-tolerant sugarbeet line were analysed from growth regimes where plants were grown either under visible radiation alone or with supplemental UV-B| Photosynthetic pigments and partial reactions of photosynthesis| including potential yield and quantum yield under illumination| non-photochemical quenching (q(NPQ)) and photochemical quenching (q(P))| were measured to assess plant response. The combination of Cercospora a and supplemental UV-B radiation in the sensitive line resulted in a decreased photosynthetic efficiency| shown by q(NPQ) and quantum yield under illumination as compared with that for either stress applied alone. The F(v)/F(m) was unchanged for plants subjected to UV-B radiation without infection| although the q(NPQ) decreased| The Cercospora-tolerant line showed no significant differences under the different treatments| Thus| the line tolerant to Cercospora infection also proved to be tolerant to UV-B radiation alone and in combination with the infection. 5249,2000,4,3,Disagreement between predictions of the future behavior of the Arctic Oscillation as simulated in two different climate models: Implications for global warming,Two global climate models (HadCM2 and ECHAM) forced with the same greenhouse-gas scenario (IS92a) are found to disagree in their simulated long-term trends of the intensity of the Arctic Oscillation (AO)| an atmospheric circulation pattern of the Northern Hemisphere. The simulated AO trends are strongly dependent on the model and on the initial conditions of the simulations. The simulated winter temperature increase averaged over the Northern hemisphere is very similar in both models. However| the effect of the different AO trends on temperature causes clear differences in the predicted regional warming| which are reduced if the effects of the AO is linearly discounted. The uncertainty in the predictions of circulation changes has impacts bn the estimation of regional temperature changes. 5178,2000,4,4,Dissolution characteristics of liquid carbon dioxide injected at the intermediate depth of the ocean,The solubility| the surface concentration and the dissolution behavior of carbon dioxide in deep sea were numerically investigated. Base on the calculations the relations between the surface concentration of liquid carbon dioxide droplet with the hydrate film and the solubility and those between the ambient carbon dioxide concentration in the plume and the dissolution rate were obtained. The results show that a carbon dioxide droplet is released both at 1000 m in depth with the initial droplet diameter of 0.011 m or less and at 1500 m in depth with a diameter of 0.015 m or less| and the droplet is completely dissolved below 500 m in depth. The hydrate film acts as a resistant layer for the dissolution of liquid carbon dioxide| and the effect of the hydrate film on the dissolution of liquid carbon dioxide depended upon the depth. 5256,2000,4,4,Dissolution of buoyant CO2 drops in a counterflow water tunnel simulating the deep ocean waters,We investigated the dissolution of CO:! drops in a high pressure counterflow water tunnel simulating ocean conditions down to 2000 m below the ocean surface. In comparison of the behavior of the buoyant CO2 drops observed in our experiments with that reported previously for motionless CO2 drops in seawater or water| the following significant differences are noticed: (1) the CO2 drops in buoyant motion dissolve much faster than the motionless CO2 drops and (2) hydrate does not always form on the buoyant CO2 drops| as it was reported in the literature to be an unavoidable phenomenon on the motionless drops. This suggests that buoyant motion influences the physical and chemical behavior of the CO2 drops in seawater dramatically. (C) 2000 Elsevier Science Ltd. All rights reserved. 5315,2000,5,4,Ecological response of mammals to global warming in the late Paleocene and early Eocene,http://www.tandfonline.com/doi/abs/10.1080/11035890001221077
5254,2000,2,2,Economic analysis of the potential impact of climate change on recreational trout fishing in the Southern Appalachian Mountains: An application of a nested multinomial logit model,Global warming due to the enhanced greenhouse effect through human activities has become a major public policy issue in recent years. The present study focuses on the potential economic impact of climate change on recreational trout fishing in the Southern Appalachian Mountains of North Carolina. Significant reductions in trout habitat and/or populations are anticipated under global warming since the study area is on the extreme margins of trout habitat of the eastern U.S. The purpose of this study is to estimate the potential welfare loss of trout anglers due to global warming. A nested multinomial logit model was developed and estimated to describe the angler's fishing choice behavior. The estimated median welfare loss (Compensating Variation) range from $5.63 to $53.18 per angler per single occasion under the various diminished trout habitat and/or population scenarios. 3089,2000,3,4,Economics of mitigating greenhouse gas emissions from solid waste in Lebanon,Global climate change has been one of the challenging environmental concerns facing policy makers over the past decade. The characterization of the wide range of greenhouse gas (GHG) emission sources and sinks| as well as their behavior in the atmosphere| remains a continuing activity in many countries| Solid waste is considered a source of greenhouse gas emissions owing to microbial decomposition of organic materials| which constitute the greater portion of solid waste. The extent of these emissions is highly dependent on waste management practices. In many countries| landfills remain an essential part of any waste management system and often the only economic form of municipal solid waste disposal. This paper describes solid waste management practices in Lebanon| estimates the corresponding current and future greenhouse gas emissions from this sector| and proposes mitigation alternatives to reduce these emissions. An economic assessment of these alternatives in the context of characteristics specific to the country is also presented in terms of equivalent cost of emission reduction. 5210,2000,3,4,Effect of nitrogen fertilization| cropping and irrigation on soil air composition and nitrous oxide emission in a loamy clay,Most of the nitrous oxide (N2O) in the atmosphere| thought to be involved in global warming| is emitted from soil. Although the main factors controlling the production of N2O in soil are well known| we need more quantitative data on the interactions of soil and the environment in the soil that affect the emission. We therefore studied the effects of irrigation| cropping (fallow| barley with grass undersown) and N fertilization (unfertilized| 103 kg N ha(-1)) on the composition of soil air and direct N2O emission from soil (using the closed chamber method) in a factorial field experiment on a well-structured loamy clay soil during 1 June-22 October 1993. The measurements were made weekly during the growing season and three times after harvesting. The composition of the soil air did not indicate severe anoxia in any treatment or combination of treatments| but the accumulation of N2O in the soil air indicated that hypoxia was common. At the start of the irrigation the emissions were small| even though there was much ammonium and nitrate in the soil and therefore a potential for emission of N2O produced by both nitrification and denitrification. Larger emissions occurred later. The largest emissions were found when 60-90% of the soil pore space was filled with water. Irrigation and fertilization with N both roughly doubled the cumulative N2O emission. Growing a crop decreased it by a factor of 3-7. Most N2O was lost from the irrigated fertilized soil under fallow (3.5 kg N ha(-1))| and least from the unirrigated unfertilized soil under barley (0.1 kg N ha(-1)). 5299,2000,4,3,Effect of water vapor feedback on internal and anthropogenic variations of the global hydrologic cycle,Using two versions of the GFDL coupled ocean-atmosphere model| one where water vapor anomalies are allowed to affect the longwave radiation calculation and one where they are not| we examine the role of water vapor feedback in internal precipitation variability and greenhouse-gas-forced intensification of the hydrologic cycle. Without external forcing| the experiment with water vapor feedback produces 44% more annual-mean| global-mean precipitation variability than the one without. We diagnose the reason for this difference: In both experiments| global-mean surface temperature anomalies are associated with water vapor anomalies. However| when water vapor interacts with longwave radiation|the temperature anomalies are associated with larger anomalies in surface downward longwave radiation. This increases the temperature anomaly damping through latent heat flux| creating an evaporation anomaly. The evaporation anomaly| in turn| leads to an anomaly of nearly the same magnitude in precipitation. In the experiment without water vapor feedback| this mechanism is absent. While the interaction between longwave and water vapor has a large impact on the global hydrologic cycle internal variations| its effect decreases as spatial scales decrease| so water vapor feedback has only a very small impact on grid-scale hydrologic variability. Water vapor feedback also affects the hydrologic cycle intensification when greenhouse gas concentrations increase. By the 5th century of global warming experiments where CO2 is increased and then fixed at its doubled value| the global-mean precipitation increase is nearly an order of magnitude larger when water vapor feedback is present. The cause of this difference is similar to the cause of the difference in internal precipitation variability: When water vapor feedback is present| the increase in water vapor associated with a warmer climate enhances downward longwave radiation. To maintain surface heat balance| evaporation increases| leading to a similar increase in precipitation. This effect is absent in the experiment without water vapor feedback. The large impact of water vapor feedback on hydrologic cycle intensification does not weaken as spatial scales decrease| unlike the internal variability case. Accurate representations of water vapor feedback are therefore necessary to simulate global-scale hydrologic variability and intensification of the hydrologic cycle in global warming. 3061,2000,2,4,Effects and outcomes of Caribbean hurricanes in a climate change scenario,Hurricanes are complex disturbance systems with significant effects on vegetation and built-up land. This paper summarizes research on the effects and outcomes of hurricanes on Caribbean forests. Twelve effects and outcome topics are presented: sudden and massive tree mortality; delayed patterns of tree mortality; alternative methods of forest regeneration; opportunities for a change in successional direction; high species turnover and opportunities for species change in forests; diversity of age classes; faster biomass and nutrient turnover; species substitutions and changes in turnover time of biomass and nutrients; lower aboveground biomass in mature vegetation; carbon sinks; selective pressure on organisms; and convergence of community structure and organization. Effects of hurricanes on urban systems are also discussed. While there is scientific uncertainty as to whether hurricane frequencies and intensity will change as a result of global climate change| available understanding on the effects and outcomes of hurricanes can be used to anticipate possible effects of either increasing or decreasing hurricane frequency and intensity. Proposed mitigation actions and research priorities can be effective and desirable even if the frequency and intensity of hurricanes remains unchanged. (C) 2000 Elsevier Science B.V. All rights reserved. 3084,2000,2,4,Effects of elevated CO(2) and temperature-grown red and sugar maple on gypsy moth performance,Few studies have investigated how tree species grown under elevated CO(2) and elevated temperature alter the performance of leaf-feeding insects. The indirect effects of an elevated CO(2) concentration and temperature on leaf phytochemistry| along with potential direct effects on insect growth and consumption| may independently or interactively affect insects. To investigate this| we bagged larvae of the gypsy moth on leaves of red and sugar maple growing in open-top chambers in four CO(2)/temperature treatment combinations: (i) ambient temperature| ambient CO(2); (ii) ambient temperature| elevated CO(2) (+ 300 mu L L(-1) CO(2)); (iii) elevated temperature (+ 3.5 degrees C)| ambient CO(2); and (iv) elevated temperature| elevated CO(2). For both tree species| leaves grown at elevated CO(2) concentration were significantly reduced in leaf nitrogen concentration and increased in C:N ratio| while neither temperature nor its interaction with CO(2) concentration had any effect. Depending on the tree species| leaf water content declined (red maple) and carbon-based phenolics increased (sugar maple) on plants grown in an enriched CO(2) atmosphere. The only observed effect of elevated temperature on leaf phytochemistry was a reduction in leaf water content of sugar maple leaves. Gypsy moth larval responses were dependent on tree species. Larvae feeding on elevated CO(2)-grown red maple leaves had reduced growth| while temperature had no effect on the growth or consumption of larvae. No significant effects of either temperature or CO(2) concentration were observed for larvae feeding on sugar maple leaves. Our data demonstrate strong effects of CO(2) enrichment on leaf phytochemical constituents important to folivorous insects| while an elevated temperature largely has little effect. We conclude that alterations in leaf chemistry due to an elevated CO(2) atmosphere are more important in this plant-folivorous insect system than either the direct short-term effects of temperature on insect performance or its indirect effects on leaf chemistry. 3076,2000,2,4,Effects of global climate change on the US forest sector: response functions derived from a dynamic resource and market simulator,A multiperiod| regional| mathematical programming economic model is used to evaluate the potential economic impacts of global climatic change on the US forest sector. A wide range of scenarios for the biological response of forests to climate change are developed| ranging from small to large changes in forest growth rates. These scenarios are simulated in the economic forest sector model and results are summarized in response functions that may be used instead of rerunning the model as improved or altered biological response scenarios arise. The response functions are used to characterize broad impacts of climate change on the sector. We find that aggregate impacts (across all consumers and producers in the sector) are relatively small but that producers income and future welfare 30 to 40 yr in the future are most at risk. The forest sector is found to have adjustment mechanisms that mitigate climate change impacts| including interregional migration of production| substitution in consumption| and altered stand management. 3067,2000,2,4,Effects of temperature and moisture on carbon respired from decomposing woody roots,Controls of temperature and moisture on root decomposition have not been well studied despite their direct relevance to climate change impacts on root carbon flux. The main objective of this laboratory study was to examine the respiration response of Sitka spruce| Douglas-fir| western hemlock| ponderosa pine| and lodgepole pine decomposing roots (1-3 cm in diameter) to temperature and moisture change. Roots of Sitka spruce| Douglas-fir and western hemlock| and ponderosa pine and lodgepole pine were collected from Cascade Head| H.J. Andrews| and Pringle Falls site| respectively. Dead root respiration increased with temperature and reached the maximum at 30-40 degreesC| and then decreased. Analysis of covariance indicated that the Q(10) of root decomposition rate was influenced significantly (p<0.01) by incubation temperature range 5-40'Solomon discusses what has worked and what has not worked in emissions trading systems from the standpoint of environmental justice. He suggests that all instances of environmental injustice should be recognized and addressed."
5258,2000,3,4,Energy efficiency fallacies revisited,A number of governments including that of the UK subscribe to the belief that a national program devoted to raising energy efficiency throughout the economy provides a costless - indeed profitable - route to meeting international environmental obligations. This is a seductive policy. It constitutes the proverbial "free lunch"- not only avoiding politically unpopular measures like outlawing| taxing or rationing offending fuels or expanding non-carboniferous sources of energy like nuclear power but doing so with economic benefit. The author of this contribution came to doubt the validity of this solution when it was offered as a way of mitigating the effect of the OPEC price hikes of the 1970| maintaining that economically justified improvement in energy efficiency led to higher levels of energy consumption at the economy-wide level than in the absence of any efficiency response. More fundamentally| he argues that there is no case for preferentially singling out energy| from among all the resources available to us| for efficiency maximization. The least damaging policy is to determine targets| enact the restrictive measures needed to curb consumption| and then leave it to consumers - intermediate and final - to reallocate all the resources available to them to best effect subject to the new enacted constraints and any others they might be experiencing. There is no reason to suppose that it is right for all the economic adjustment following a new resource constraint to take the form of improvements in the productivity of that resource alone. As many others have argued| any action to impose resource constraint entails an inevitable economic cost in the shape of a reduction in production and consumption possibilities: there would be no "free lunch". In the last few years debate about the validity of these contentions has blossomed| especially under the influence of writers on the Western side of the Atlantic. In this contribution the author outlines the original arguments for questioning whether raised efficiency leads to lower consumption| reports more recent developments and offers some insights as food for further thought. (C) 2000 Elsevier Science Ltd. All rights reserved. 5267,2000,2,4,Enhancing effect of marine oligotrophy on environmental concentrations of particle-reactive trace elements,A biogeochemical model has been previously developed that explains the inverse and nonlinear relationship between Po-210 concentration in zooplankton and their biomass| under oligotrophic conditions in French Polynesia. in this study the model structure was reviewed to determine a set of biogeochemical behaviors of Po-210| proposed to be critical to its environmental enhancement under oligotrophy: this set was then used to identify 25 other elements with comparable behaviors to Po-210. Field investigation in the Timer Sea showed that four of these a priori identified elements| viz. Cd| Co| Ph| and Mn as well as Cr and Ni| showed elevated water concentrations with reduced particle removal rates in the euphotic zone| results that are consistent with those previously obtained for Po-210 and the proposed explanatory model. These findings point to the enhanced susceptibility to contamination with particle-reactive elements of oligotrophic marine systems| whose degree and geographic extent may be enhanced by projected increases in sea surface temperatures from global warming. 5381,2000,5,4,Environment and climate of Quaternary periods of warming in southern West Siberia,Comparison of Pleistocene soils in complete loess sections of southern West Siberia has shown a distinct trend in evolution of soil formation and climate during Pleistocene periods of warming and has confirmed the absence of Lower and Middle Pleistocene interstadial soils attested by studies of Pleistocene loess sections in East Europe. Analysis of periodicity and duration of Pleistocene warmings allowed an inference that the Late Pleistocene climate changes differed in amplitude and frequency from those in the Early and Middle Pleistocene| when the territory of southern Siberia was dominated by moderate warm and humid climate. The amplitude and frequency of climatic fluctuations changed significantly after the Kazantsevian interglacial. Warming periods at that time were much shorter| cooler| and more arid. Despite the fact that the Holocene interglacial was cooler than the latest one (Kazantsevian| Eemian)| it was much longer and warmer than the short warmings of Early Zyryanian and Karginian time. Thus| the trend of Late Cenozoic climatic changes has been turned to warming since Holocene time. It was found out that| during nearly each Pleistocene interglacial| thermophile Central Asian freshwater mollusks migrated to West Siberia. Hence| during large warming periods| Central Asia and Western Kazakhstan had developed drainage networks and were characterized by a humid climate. The hypsometry of warm Kazantsevian alluvium indicates that the river network evolved toward higher altitudes after the rise of the sea level associated with global warming and thawing of unstable ice sheets. Warming| along with greater humidity| led to higher stand of groundwaters and swamping of continental low plains. In the Holocene| despite some variability in the duration of alternating warm and cold periods| they show distinct recurrence at a periodicity of about 500 years. The latest cold period (Small Ice Age) lasted from the middle of the 15th to the end of the 19th century| when the next natural warming started. The thermal parameters of this warm period are close to those in the early Middle Age| and its expected duration is about 500 years. 5261,2000,4,3,Environmental comparison metrics for life cycle impact assessment and process design,Metrics (potentials| potency factors| equivalency factors or characterization factors) are available to support the environmental comparison of alternatives in application domains like process design and product life-cycle assessment (LCA). These metrics typically provide relative insights into the implicit concern associated with chemicals| emissions and resource consumption in the context of human health| ecological health and resource depletion. The approaches used to derive the metrics range in their Site-specificity| complexity| comprehensiveness| sophistication and uncertainty. It is therefore often necessary to consider the use of more than one approach within the context of a given impact category to help support a decision. In this paper we outline some of the strengths and weaknesses of available approaches in the commonly considered categories of global warming| stratospheric ozone depletion| tropospheric ozone (smog) creation| eutrophication/nutrification| acidification| toxicological impacts and resource depletion. 3113,2000,2,4,Environmental controls on growth of the massive coral Porites,Annual density banding provided growth characteristics for 245 similar-sized| massive colonies of Porites from similar locations on 29 reefs from across the length and breadth of the Great Barrier Reef (GBR)| Australia. Values obtained were density| extension rate| and calcification rate. Tissue thickness| the depth to which skeletons were occupied by tissue at the time of collection| was also measured. Extension rate| calcification rate| and tissue thickness were significantly greater at the top of colonies than at the sides. Extension rate and calcification rate decreased from north to south along the GBR (latitudinal range of similar to 9 degrees) and were significantly and directly related to annual average sea surface temperature (SST; range similar to 25-27 degrees C). For each 1 degrees C rise in SST| average annual calcification increased by 0.39 g cm(-2) year(-1) and average annual extension increased by 3.1 mm year(-1) (c.f. average values of 1.63 g cm(-2) year(-1) and 12.9 mm year(-1)| respectively). Density was inversely correlated with extension rate and increased with distance offshore. Data for massive Porites colonies from the GBR were extended though 20 degrees of latitude and an average annual SST range of 23-29 degrees C using published data for the Hawaiian Archipelago (Grigg| R.W.| 1981. Coral reef development at high latitudes in Hawaii. Proc. 4th Int. Coral Reef Symp.| Manila| Vol. 1| pp. 687-693; Grigg| R.W.| 1997. Paleoceanography of coral reefs in the Hawaiian-Emperor Chain - revisited. Coral Reefs 16| S33-S38) and Phuket| Thailand (Scoffin. T.P.| Tudhope. A.W.| Brown. B.E.| Chansang. H.| Cheeney. R.F.| 1992. Patterns and possible environmental controls of skeletogenesis of Porites lutea| South Thailand. Coral Reefs 11| 1-11). The response of calcification rate to temperature remained linear. Variation in annual average SST accounted for 84% of the variance. For each 1 degrees C rise in SST| average annual calcification increased by 0.33 g cm(-2) year(-1) and average annual extension increased by 3.1 mm year(-1) (c.f. average values of 1.50 g cm(-2) year(-1) and 11.6 mm year(-1)| respectively). The sensitivity of calcification rate in Porites to SST| combined with observed 20th Century increases in SSTs| suggests that calcification rates may have already significantly increased along the GBR in response to global climate change. (C) 2000 Elsevier Science B.V. All rights reserved. 3149,2000,4,3,Estimating disease risk at the whole plant level with General Circulation Models,General Circulation Models (GCMs) have been developed to assess the impacts of potential global climate change. However| these models do not provide specific weather information at the whole-plant level and thus provide only very gross estimates of conditions that affect plant and disease development. Also| climatic change may increase the frequency of extreme events that influence plant production more than changes in daily or monthly averages. One solution is a simulation approach that can scale weather information from the global down to the plant scale. Over the last 4 years| we have been developing methods to hierarchically define current and forecast weather conditions down to the whole-plant level based on nested high-resolution atmospheric (mesoscale) numerical models. Two hierarchical mesoscale model approaches were tested to downscale weather data in a vineyard. The first| known as the Localized Mesoscale Forecast System (LMFS) uses surface databases to 'localize' mesoscale output. The second| known as the Canopy-Mesoscale Forecast System (CMFS)| uses a boundary layer model to downscale mesoscale output. To illustrate the utility of this approach we focused on surface wetness duration (SWD)| a variable with high spatial and temporal variability. SWD is also a critical variable for prediction of plant disease. Simulations of SWD with on-site input data were compared to those derived from the mesoscale models and to on-site sensors. Forecasts of atmospheric variables by the two systems were compared to on-site observations. Success in this effort leads us to extend this method to GCMs where factors such as temperature| rainfall| relative humidity| and surface wetness can be estimated within plant and crop canopies. We explore the implications of this work on evaluating the assessment of climate change on the risk of plant disease development. (C) 2000 Elsevier Science Ltd. All rights reserved. 5160,2000,2,4,Estimating species-based community integrity under global warming| with special reference to the western Mediterranean region,Climate-based estimates of the fitness of the main structural elements of several western Mediterranean plant communities were used to estimate potential community integrity and its consequent vulnerability under a global-change scenario involving warming but no net drying. Results for a simple Quercus ilex community suggest expansion northward and inland under warming but with significant loss of area currently covered by the community. The data for estimating such changes in potential community integrity and areal coverage can be readily obtained from climatic envelope models. Mapping can be done by interpolation or by pixel-based GIS methods. 5380,2000,3,3,Estimation of methane emission from a deep-water rice field using Landsat TM and NOAA AVHRR: a case study of Bangkok Plain,A rapid increase in the concentration of greenhouse gases (GHGs) aggravates global warming of the Earth's atmosphere. It is necessary to monitor the emission rate as well as emission quantity of methane as a major component of GHGs. The objective of this study is to develop mathematical models for the estimation of methane emission from a deep-water rice field| using information extracted from satellite images. The methodology proposal in the study consists of two models: firstly| the true ground data of the monthly biomass of rice and average methane emission rate were analysed to set up the methane emission rate model; secondly. the biomass of rice and Various reflectances of the wavelength obtained from satellite images were investigated. It has been found that Landsat TM band 3| band 4| band 5| band 7 and the normal differential vegetation index as well as the National Oceanic and Atmospheric Administration AVHRR band I. band 7 and NDVI are well related to the biomass of rice. which can be used to estimate the biomass of rice| the so-called remote sensing (RS) biomass model. Finally the estimation of methane emission can be manipulated by using the methane emission rate model coupled with the RS biomass model based on data from satellite imageries. Comparison between estimated methane emission from satellite images and experimental methane emission data measured at the Prachinburi Rice Research Center reveals that the methodology proposed can be used to estimate methane emission from a deep-water rice field with satisfactory accuracy| particularly during the reproductive stage of rice and maturation. 5290,2000,2,4,Estimation on the response of glaciers in China to the global warming in the 21st century,Glaciers in China can be categorized into 3 types| i.e. the maritime (temperate) type| sub-continental (sub-polar) type and extreme continental (polar) type| which take 22%| 46% and 32% of the total existing glacier area (59 406 km(2)) respectively| Researches indicate that glaciers of the three types show different response patterns to the global warming. Since the Max;ima of the Little Ice Age (the 17th century)| air temperature has risen at a magnitude of 1.3 degrees C on average and the glacier area decreased corresponds to 20% of the present: total glacier area in western China. II: is estimated that air temperature rise in the 2030s| 2070s and 2100s will be of the order of 0.41.2| 1.2-2.7 and 2.1-4.0 K in western China. With these scenarios| glaciers in China will suffer from further shrinkage by 12%| 28% and 45% by the 2030s| 2070s and 2100s. The uncertainties may account for 30%-67% in 2100 in China. 5313,2000,3,4,Evaluation of C(4)F(8)O as an alternative plasma-enhanced chemical vapor deposition chamber clean chemistry,The perfluorinated ether| C(4)F(8)O| has been investigated as an alternative to C(2)F(6) and C(3)F(8) to reduce global warming emissions from plasma-enhanced chemical vapor deposition (PECVD) chamber cleaning processes. A designed experiment was completed with C(4)F(8)O evaluating the effect of gas flow rate| oxygen dilution ratio| and chamber pressure on chamber clean time and global warming emissions. Analysis was completed using response surface methodology and neural network modeling. The results were compared to chamber clean times and emissions from typical C(2)F(6) and C(3)F(8) processes released for the reactor| a Novellus Concept One 200 dielectric PECVD tool. Following the designed experiment| additional data were gathered to examine the effect of radio frequency power and further variations in the other three variables on the process. Results indicate that when compared to C(2)F(6) and C(3)F(8) processes| shorter chamber clean times in combination with a significant reduction in global warming emissions are possible using the C(4)F(8)O chemistry. (C) 2000 The Electrochemical Society. S0013-4651(99)06-011-5. All rights reserved. 5310,2000,3,2,Evaluation of CO2 emissions in the life cycle of tokamak fusion power reactors,Global warming is one of the most serious problems which human beings are currently facing. Carbon dioxide (CO2) from power plants is considered one of the major causes of global warming. In the present study| CO2 emissions from tokamak fusion power plants are compared with those from present power generating technologies. Plasma parameters are calculated by a systems code that couples the ITER physics| toroidal field coil shape and cost calculation. CO2 emissions from construction and operation are evaluated by multiplying component volume by the CO2 emission intensities of the component materials. The reactor building| balance of plant| etc.| are scaled from the ITER reference power reactor ('ITER-like') by use of the Generomak model. The most important finding is that CO2 emissions from fusion reactors are less than those from photovoltaic systems and less than double those from fission reactors. The other findings are that: (i) Most CO2 emissions from fusion reactors are from materials. (ii) CO2 emissions from reactor construction account for almost 60-70% of the total| with the rest coming from reactor operation. (iii) The reversed shear reactor can reduce CO2 emissions by half compared with the ITER-like reactor. It is concluded that tokamak fusion reactors are excellent for their low CO2 emission intensity| and that they can be one of the effective energy supply technologies to solve global warming. 5257,2000,4,3,Evaluation of ocean and climate models using present-day observations and forcing,The most common method used to evaluate climate models involves spinning them up under perpetual present-day forcing find comparing the model results with present-day observations. This approach clearly ignores any potential long-term memory of the model ocean to past climatic conditions. Here we examine the validity of this approach through the 6000-year integration of a coupled atmosphere-ocen-sea-ice model. The coupled model is initially spun-up| with atmospheric CO2 concentrations and orbital parameters applicable for 6KBP. The model is then integrated forward in time to 2100. Results from this transient coupled model simulation are compared with the results from two additional simulations| in which the model is spun up with perpetual 1850 (preindustrial) and 1998 (present-day) atmospheric CO2 concentrations and orbital parameters. This comparison leads to substantial differences between the equilibrium climatologies and the transient simulation| even at 1850 tin weakly ventilated regions)| prior to any significant changes in atmospheric CO2. When compared to the present-day equilibrium climatology| differences fire very large: the global mean surface air and sea surface temperatures are similar to0.5 degreesC and similar to0.4 degreesC colder respectively deep ocean temperatures are substantially cooler Southern Hemisphere sea-ice cover is 38% larger| and the North Atlantic conveyor 16% weaker in the transient case. These differences are due to the long timescale memory of the deep ocean to climatic conditions which prevailed throghout the late Holocene| as well as to its large thermal inertia. It is also demonstrated that a 'cold start' global warming simulation tone that starts from a 1998 equilibrium climatology) underestimates the global temperature increase at 2100 by similar to 10%. Our results question the accuracy of current techniques for climate model evaluation find underline the importance of using using paleoclimatic simulations in parallel with present-day simulations in this evaluation process. 5242,2000,3,3,Evaluation of pentafluoroethane and 1|1-diffuoroethane for a dielectric etch application in an inductively coupled plasma etch tool,In this work| a combination of two hydrofluorocarbon compounds| pentafluoroethane (FC-125| C2HF5) and 1|1-difluoroethane (FC-152a| CF2H-CH3)| was evaluated as a potential replacement for perfluorocompounds in dielectric etch applications. A high aspect ratio oxide via etch was used as the test vehicle for this study| which was conducted in a commercial inductively coupled high density plasma etch tool. Both process and emissions data were collected and compared to those provided by a process utilizing a standard perfluorinated etch chemistry (C2F6). Global warming (CF4| C2F6| CHF3) and hygroscopic gas (HF| SiF4) emissions were characterized using Fourier transform infrared (FTIR) spectroscopy. FC-125/FC-152a was found to produce significant reductions in global warming emissions| on the order of 68 to 76% relative to the reference process. Although etch stopping| caused by a high degree of polymer deposition inside the etched features| was observed| process data otherwise appeared promising for an initial study| with good resist selectivity and etch rates being achieved. 5324,2000,2,4,Evidence for a link between climate and northern wetland methane emissions,Wetlands are an important source of atmospheric methane (CH4)| but the strength of this source and its sensitivity to potential changes in climate are still uncertain. In this study| continuous measurements from 1990 to 1998 of atmospheric CH| from the Canadian observational sites at Fraserdale (49 degrees 53'N 81 degrees 34'W) and Alert (82 degrees 27'N 62 degrees 31'W) are used to estimate CH| emissions from the Hudson Bay Lowland (HBL)| a 320|000 km(2) semicontinuous wetland region in central Canada. The HBL comprises similar to 10% of the total area of northern wetlands. A conceptually simple approach was used to calculate the methane emission flux using the CH4 concentration difference between Alert and Fraserdale| the residence time of the air mass over the HBL| and the mixing height of the convective boundary layer. Emission rates estimated using this approach for 1990 compare well with empirical aircraft and tower flux measurements made within the HBL during the same time period| thus indicating that the methodology used is reasonable. Annual CH4 emission rates range from 0.23 to 0.50 Tg CH4 yr(-1) and are much lower than many empirical flux measurements observed at other northern wetland sites. A seasonal temperature sensitivity with a Q(10) of about 4 was found. Moreover| the observed interannual variations in emissions are well correlated to variations in annual air temperatures corresponding to a sensitivity of Q(10) approximate to 7. That is| a 10 degrees C change in annual temperature would result in a sevenfold change in wetland emissions which is much larger than Q(10) values used in current global CH4 models (typically Q(10) approximate to 1.5). Our findings suggest that northern wetland emissions are probably overestimated to date but may increase significantly due to predicted global warming. 5283,2000,2,4,Evidence that decomposition rates of organic carbon in mineral soil do not vary with temperature,It has been suggested that increases in temperature can accelerate the decomposition of organic carbon contained in forest mineral soil (C-s)| and| therefore| that global warming should increase the release of soil organic carbon to the atmosphere(1-6). These predictions assume| however| that decay constants can be accurately derived from short-term laboratory incubations of soil or that in situ incubations of fresh litter accurately represent the temperature sensitivity of C-s decomposition. But our limited understanding of the biophysical factors that control C-s decomposition rates| and observations of only minor increases in C-s decomposition rate with temperature in longer-term forest soil heating experiments(7-12) and in latitudinal comparisons of C-s decomposition rates(13-15) bring these predictions into question. Here we have compiled C-s decomposition data from 82 sites on five continents. We found that C-s decomposition rates were remarkably constant across a global-scale gradient in mean annual temperature. These data suggest that C-s decomposition rates for forest soils are not controlled by temperature limitations to microbial activity| and that increased temperature alone will not stimulate the decomposition of forest-derived carbon in mineral soil. 5141,2000,2,2,External control of 20th century temperature by natural and anthropogenic forcings,A comparison of observations with simulations of a coupled ocean-atmosphere general circulation model shows that both natural and anthropogenic factors have contributed significantly to 20th century temperature changes. The model successfully simulates global mean and Large-scale Land temperature variations| indicating that the climate response on these scales is strongly influenced by external factors. More than 80% of observed multidecadal-scale global mean temperature variations and more than 60% of 10- to 50-year Land temperature variations are due to changes in external forcings| Anthropogenic global warming under a standard emissions scenario is predicted to continue at a rate similar to that observed in recent decades. 5318,2000,2,4,Forecasting the changes in lake water quality in response to climate changes| using past relationships between meteorological conditions and water quality,In order to forecast the effects of global warming on the water environment| the relationship between meteorological conditions and lake water quality was investigated statistically using 17 years of monitoring data obtained from a shallow eutrophic lake| Lake Kasumigaura. The usefulness of the DPY (difference from the previous year) method was confirmed for removing the watershed change (e.g. land cover| population| etc.). From the analysis of the relationships between air temperature and water temperature on a monthly basis| the delay of time was seen to be negligible| but the gain was reduced due to the high frequency of change. As the amount of precipitation affected their relationship on a yearly basis| the slopes of 1.0-1.2 degrees C water temperature/degrees C air temperature were determined with the DPY method by excluding the combinations of the years having large difference in annual precipitation. The deterioration of lake water quality| such as increases in COD (chemical oxygen demand) and decreases in transparency| was quantitatively assessed as corresponding to an increase in air temperature. In addition| we found that higher precipitation led to high nitrogen concentrations on a monthly basis| as well as on a yearly basis| probably induced by both the runoff of soilwater having high concentrations and the lowering of residence times of lake water. Copyright (C) 2000 John Wiley & Sons| Ltd. 5312,2000,2,3,Forest growth and species distribution in a changing climate,Climate change has many potential effects on plants| some detrimental to growth| others beneficial. Increasing CO2 concentration can increase photosynthetic rates| with the greatest increases likely to be in Cg plants growing in warm dry conditions. Increasing temperature directly affects plant growth through effects on photosynthetic and respiration rates. However| plants have a considerable ability to adapt to changing conditions and can tolerate extremely high temperatures| provided that adequate water is available. Increasing temperature may increase vapor pressure deficits of the air| and thereby increase transpiration rates from most plant canopies. Effects are likely to vary among plant communities| with forests generally experiencing greater increases in transpiration rates than|grasslands. These increases in transpiration are likely to be reduced by stomatal closure in response to increasing CO2 concentration. In many areas| precipitation will probably increase with global warming; however| these increases may be insufficient to meet the increased transpirational demand by plant canopies. Increasing temperature is likely to increase soil organic matter decomposition rates so that nutrients may be more readily mineralized and made available to plants. In highly fertile systems| this could lead to nutrient losses through leaching. For different combinations of increases in temperature and CO2 concentration| and for systems primarily affected by water or nutrient limitations| different overall effects on plant productivity can be expected. Responses will be negative in some circumstances and positive in others| but on the whole| catastrophic changes to forest growth seem unlikely under most conditions. In contrast| ecological consequences of climate change are potentially more serious. The distribution of many species tends to be limited to a narrow range of environmental conditions. Climate conditions over much of a species' current natural range may therefore become unsuitable| leading to significant decline of forests or of particular species within forests. 5278,2000,3,4,Formation of CO2 hydrate in the presence of montmorillonite,Since direct disposal of CO2 in the ocean is a highly potential sequestration option| the process of oceanic disposal of CO2 has attracted much attention as an effective technology that can declerate global-warming. When CO2 is discharged in deep sea region subject to high pressure and low temperature| CO2 hydrate can be formed easily. For the design pur pose of the CO2 disposal process| the formation rate of the CO2 hydrate is required. Furthermore| it is well known that natural gas is often found at off-shore| buried under oceanic sediments. It should be necessary| therefore| to understand the interaction between the gas hydrate and the solid materials in the deep sea bed. The purpose of this paper is to investigate experimentaly the effect of clay materials in deep sea bed on rate of formation of CO2 hydrate. Since montmorillonites are the main components of the clay materials| the authors used two kinds of montmorillonites| Na- and Ca-montmorillonite. The Na-montmorillonite is hydrophillic| while the Ca-montmorillonite is hydrophobic. The rate of formation of the hydrate was determined from measurements of rate of consumption of CO2. During the process of formation of hydrate| both temperature and pressure in the reactor deviate from the initially setted values. The authors| therefore| studied the relation between the rate of formation of hydrate at an initial stage and the content of the montmorillonite. It was found that the initial rate of formation of hydrate drops as the content of Na-montmorillonite increases. On the other hand| the effect of the Ca-montmorillonite was not so significant.
5205,2000,2,4,Fragile transmission cycles of tick-borne encephalitis virus may be disrupted by predicted climate change,Repeated predictions that vector-borne disease prevalence will increase with global warming are usually based on univariate models. To accommodate the full range of constraints| the present-day distribution of tick-borne encephalitis virus (TBEv) was matched statistically to current climatic variables| to provide a multivariate description of present-day areas of disease risk. This was then applied to outputs of a general circulation model that predicts how climatic variables may change in the future| and future distributions of TBEv were predicted for them. The expected summer rise in temperature and decrease in moisture appears to drive the distribution of TBEv into higher-latitude and higher-altitude regions progressively through the 2020s| 2050s and 2080s. The final toe-hold in the 2080s may be confined to a small part of Scandinavia| including new foci in southern Finland. The reason for this apparent contraction of the range of TBEv is that its transmission cycles depend on a particular pattern of tick seasonal dynamics| which may be disrupted by climate change. The observed marked increase in incidence of tick-borne encephalitis in most parts of Europe since 1993 may be due to non-biological causes| such as political and sociological changes. 5203,2000,2,4,Frequency and characteristics of severe storms in the Urals and their influence on the development| structure and management of the boreal forests,After an unusual number of storms in the Urals in the early 1990s and with the global warming over the past 100 years| there were fears of increasing storm frequency in this region. This study investigates meteorological data| aspects of windthrow and the beginnings of reforestation after windthrow under different silvicultural treatments. The meteorological data were collected from a region covering an area of over 20 million ha of the Urals to the west and to the east. Storm frequency was analysed for 1946-1996 and windthrow events for 1965-1996| according to the availability of data. Regeneration experiments were begun on two experimental plots of 20 and 12 ha| respectively. Each was divided into three sub-plots| one being left untouched| one roughly logged and the last roughly logged and then replanted. Mean temperatures in the Urals showed a rise during the last more than 100 years| indeed| but neither the annual number of storms nor their mean wind speed increased. Only a few forest enterprises suffered windthrow on more than 1% of their total area. Most of the windthrown trees were of medium height and diameter. With two exceptions none of the storms greatly altered the structure of the forests. With over 3700 trees taller than 20 cm and up to 11 species| the forests showed great diversity. Neither windthrow| nor logging and clearing diminished the diversity| but all reduced the abundance of most of the species. These forests| left to regenerate naturally for some decades after clear-cutting| show a much higher number of species and individual trees than intensively managed conifer forests in the Swiss Alps. Therefore| it is recommended that natural development processes be more often integrated into conventional forest management methods. (C) 2000 Elsevier Science B.V. All rights reserved. 5155,2000,2,4,Frequent non-storm washover of barrier islands| Pacific coast of Colombia,Barrier islands of the Pacific coast of Colombia repeatedly experience severe washover even when breaking waves in the eastern Pacific are low and onshore winds are calm. On the barrier island of El Choncho| recent non-storm washover events have breached a new inlet| caused rapid beach retreat| destroyed a shoreline protection structure| and flooded a small village of indigenous people so Frequently that it had to be relocated. Barrier washover may be augmented by lowered land elevations associated with earthquake-induced subsidence or long-term beach retreat| but temporally it is most closely associated with a 20 to 30 cm regional increase in sea level caused by El Nino. The contradiction of a tranquil tropical island scene simultaneously disturbed by hostile turbulent washover may be unique at present| but it exemplifies how coastal plains throughout the world would be affected if sea level were to rise rapidly as a result of global warming. 3152,2000,4,4,Fuzzy modeling approach for integrated assessments using cultural theory,It has already been noted that predicting societal responses accurately requires the use of a formal model such as cultural theory. A basic belief of cultural theory is that all societies and their underlying worldviews| irrespective of time or place| must be more or less hierarchic| more or less individualistic| more or less egalitarian| or more or less fatalistic. This approach has a potential for cross-temporal and spatial comparisons that makes it a particularly attractive instrument for a study of the human dimensions of global climate change. However| a significant difficulty in the previous attempts for utilizing cultural theory in integrated assessment models (IAMs) has been the inexactness or uncertainty inherent in both IAMs and cultural theory. In this paper we introduce a fuzzy-based modeling approach that makes use of cultural theory in integrated assessment approach to provide a mechanism for understanding the reaction of a populace to environmental policy decisions. 5282,2000,3,2,Game theoretic analysis for carbon emission permits trading among multiple world regions with an optimizing global energy model,Carbon emissions which would cause global warming were agreed to be constrained at COP3 in Kyoto. In addition| carbon emission permits trading was also approved to be introduced. The emission permits trading is expected to achieve efficient carbon emission reduction| equalizing the marginal costs of the emission reduction for the participating countries. Zn other words| the permits trading allows participants to reduce emissions where it is least expensive to do so. However| the inadequate introduction of the trading systems may impose an unfairly greater burden on settle countries| and therefore careful evaluation of the system would be indispensable for its implementation. In this paper we attempt to analyze emission permits trading| using the theory of cooperative games with a global energy model of optimization type. We assume that seven world regions as players participate in the permits trading system under the condition of the emission reduction target presented at COP3 and so on| and show the nucleolus of the grand coalition games| and the computational results of primary energy supplies and CO2 shadow prices. The insights of this research indicate that in order to stabilize the grand coalition| a noticeable amount of additional transfer of:money would be needed besides the payments associated with the emission permits transactions. (C) 2000 Scripts Technica. 5331,2000,2,4,Gas exchange and water relations of two Rocky Mountain shrub species exposed to a climate change manipulation,Gas exchange and water relations responses to warming were compared for two shrub species| Artemisia tridentata spp. vaseyana (Asteraceae)| a widely distributed evergreen species of the Great Basin and the western slope of the Rocky Mountains| and Pentaphylloides floribunda (Rosaceae)| a deciduous shrub limited in distribution to moist| high-elevation meadows. Plants were exposed to an in situ infrared (IR) climate change manipulation at the Rocky Mountain Biological Laboratory| near Crested Butte| CO. Measurements of gas exchange and water relations were made on the two species in July and August| 1993 from plants growing in situ in infrared-heated and control plots. Carbon dioxide uptake| water loss| leaf temperature| water use efficiency| and water potential were compared to test the hypothesis that leaf and soil responses to IR will cause leaf level changes in photosynthesis. Photosynthetic CO2 uptake and water use efficiency increased for A. tridentata (2.9 vs. 1.9 mu mol m(-2) s(-1) and 1.2 vs. 0.7 mmol C/mol H2O) in the heated plots compared to the controls| while water potential was significantly lower in the heated plots (-1.1 vs. -0.5 MPa). The heating treatment decreased rates of photosynthesis for P. floribunda| but not significantly so. For A. tridentata| the results are consistent with the community-level changes observed with heating. Taken together| the evidence suggests that global warming is likely to result in increasing dominance of A. tridentata in subalpine meadow habitat now dominated by forbs. 3126,2000,2,4,Gas exchange| leaf nitrogen| and growth efficiency of Populus tremuloides in a CO(2)-enriched atmosphere,Predicting forest responses to rising atmospheric CO(2) will require an understanding of key feedbacks in the cycling of carbon and nitrogen between plants and soil microorganisms| We conducted a study for 2.5 growing seasons with Populus tremuloides grown under experimental atmospheric CO(2) and soil-N-availability treatments. Our objective was to integrate the combined influence of atmospheric CO(2) and soil-N availability on the flow of C and N in the plant-soil system and to relate these processes to the performance of this widespread and economically important tree species. Here we consider treatment effects on photosynthesis and canopy development and the efficiency with which this productive capacity is translated into aboveground| harvestable yield. We grew six P| tremuloides genotypes at ambient (35 Pa) or elevated (70 Pa) CO(2) and in soil of low or high N mineralization rate at the University of Michigan Biological Station| Pellston| Michigan| USA (45 degrees 35' N| 84 degrees 42' W). In the second year of growth| net CO(2) assimilation rate was significantly higher in elevated-CO(2) compared to ambient-CO(2) plants in both soil-N treatments| and we found little evidence for photosynthetic acclimation to high CO(2). In the third year| however| elevated-CO(2) plants in low-N soil had reduced photosynthetic capacity compared to ambient-CO(2)| low-N plants| Plants in high-N sail showed the opposite response| with elevated-CO(2) plants having higher photosynthetic capacity than ambient-CO(2) plants. Net CO(2) assimilation rate was linearly related to leaf N concentration (log:log scale)| with identical slopes but different intercepts in the two CO(2) treatments| indicating differences in photosynthetic N-use efficiency| Elevated CO(2) increased tissue dark respiration in high-N soil (+22%) but had no significant effect in low-N soil(+9%). There were no CO(2) effects on stomatal conductance. At the final harvest| stem biomass and total leaf area increased significantly due to CO(2) enrichment in high-N but not in low-N soil. Treatment effects on wood production were largely attributable to changes in leaf area| with no significant effects on growth efficiency| We conclude that harvest intervals for P. tremuloides on fertile sites will shorten with rising atmospheric CO(2)| but that tree size at canopy closure may be unaffected. 3131,2000,4,4,Gas hydrate and humans,The potential effects of naturally occurring gas hydrate on humans are not understood with certainty| but enough information has been acquired over the past 30 years to make preliminary assessments possible. Three major issues are gas hydrate as (1) a potential energy resource| (2) a factor in global climate change| and (3) a submarine geohazard| The methane content is estimated to be between 10(15) to 10(17) m(3) at STP and the worldwide distribution in outer continental margins of oceans and in polar regions are significant features of gas hydrate. However| its immediate development as an energy resource is not likely because there are various geological constraints and difficult technological problems that must be solved before economic recovery of methane from hydrate can be achieved. The role of gas hydrate in global climate change is uncertain. For hydrate methane to be an effective greenhouse gas| it must reach the atmosphere| Yet there are many obstacles to the transfer of methane from hydrate to the atmosphere. Rates of gas hydrate dissociation and the integrated rates of release and destruction of the methane in the geo/hydro/atmosphere are not adequately understood. Gas hydrate as a submarine geohazard| however| is of immediate and increasing importance to humans as our industrial society moves to exploit seabed resources at ever-greater depths in the waters of our coastal oceans. Human activities and installations in regions of gas-hydrate occurrence must take into account the presence of gas hydrate and deal with the consequences of its presence. 3132,2000,2,2,Gas hydrates and global climate change,The gas hydrate phenomenon intersects with societal concerns about global climate change in at least two distinct ways: the possibility of destruction of gas hydrates exposed on or near the sea floor by global warming; and the possibility of avoiding this and other problems by taking advantage of CO2 hydrate formation during active disposal of fossil fuel CO2 in the deep ocean. This extraordinary picture of contemporary discussion of the possible destruction by mankind of one hydrate| and the creation of another| both in vast quantities in the ocean| is a tribute to the unusual nature and power of this chemical cage. 5306,2000,2,4,Genetic variation and spatial structure in sugar maple (Acer saccharum Marsh.) and implications for predicted global-scale environmental change,Current ecosystem model predictions concerning the effects of global temperature increase on forest responses do not account for factors influencing long-term evolutionary dynamics of natural populations. Population structure and genetic variability may represent important factors in a species' ability to adapt to global-scale environmental change without experiencing major alterations in current range limits. Genetic variation and structure in sugar maple (Acer saccharum Marsh.) were examined across three regions| between two stands within regions| and among four to five open-pollinated families within stands (total N = 547 genotypes) using 58 randomly amplified polymorphic DNA (RAPD) markers. Differences within open-pollinated families account for the largest portion of the total variation (29%)| while differences among regions represent less than 2% of the total variation. Genetic diversity| as indicated by estimates of percent polymorphic loci| expected heterozygosity| fixation coefficients| and genetic distance| is greatest in the southern region| which consists of populations with the maximum potential risk due to climate change effects. The high level of genetic similarity (greater than 90%) among some genotypes suggests that gene flow is occurring among regions| stands| and families. High levels of genetic variation among families indicate that vegetational models designed to predict species' response to global-scale environmental change may need to consider the degree and hierarchical structure of genetic variation when making large-scale inferences. 5170,2000,2,4,Glacier evolution in the tropical Andes during the last decades of the 20th century: Chacaltaya| Bolivia| and Antizana| Ecuador,Mass balance has been continuously monitored on Chacaltaya Glacier (16 degreesS| Cordillera Real| Bolivia) since 1991| and on the Antizana Glacier 15 (0 degrees| Ecuador) since 1995. In ablation areas| mass balance has been surveyed on a monthly scale| providing interesting details about the seasonal pattern in 2 contrasting tropical environments. Intermittent information about ice recession exists in both regions for the last 4 decades. The data point to a clear acceleration in glacier decline during this decade; ablation rates have been 3-5 times higher than during the former decades. Fluctuations measured before on 3 glaciers in northern Peru| allow the assumption that the rate at which the glaciers retreated in the tropical Andes increased in the late 1970s. The present situation is particularly dramatic for the small-sized glaciers (< 1 km(2)) and many such as Chacaltaya| could disappear in the next 10 years. As evidenced by the data collected| ablation increases significantly during the warm phases of ENSO (El Nino) and decreases during the cold phases (La Nina). Warm events becoming more frequent and intense since the late 1970s| it can be assumed that they have played an important role in the recent glacier decline in the central Andes| together with the global warming. 3062,2000,2,4,Global climate change and introduced species in United States forests,Introduced species already cause billions of dollars of damage annually in United States forests| plus massive ecological damage whose economic value has often not been estimated. The variety of impacts is staggering and includes herbivory| predation| disease| parasitism| competition| habitat destruction| hybridization| and changed disturbance regimes and nutrient cycles. How global climate change will affect these impacts has scarcely been assessed. Range changes of existing introduced species will be prominent| as many species' biogeographic ranges are set primarily by climate. Similarly| some species that might otherwise not have survived will be able to establish populations in a changed climate. It is more difficult to predict what the impacts of the introduced species will be. What is most needed are studies of the combined impacts of changing climate| CO2 and nutrients. Certain aspects of the biology of introduced species| such as evolution and autonomous dispersal| greatly complicate the prediction of spread and impact of introduced species. (C) 2000 Elsevier Science B.V. All rights reserved. 3142,2000,5,4,Global climate change and North American mammalian evolution,We compare refined data sets for Atlantic benthic foraminiferal oxygen isotope ratios and for North American mammalian diversity| faunal turnover| and body mass distributions. Each data set spans the late Paleocene through Pleistocene and has temporal resolution of 1.0 m.y.; the mammal data are restricted to western North America. We use the isotope data to compute five separate time series: oxygen isotope ratios at the midpoint of each 1.0-m.y. bin; changes in these ratios across bins; absolute values of these changes (= isotopic volatility); standard deviations of multiple isotope measurements within each bin; and standard deviations that have been detrended and corrected for serial correlation. For the mammals| we compute 12 different variables: standing diversity at the start of each bin; per-lineage origination and extinction rates; total turnover; net diversification; the absolute value of net diversification (= diversification volatility); change in proportional representation of major orders| as measured by a simple index and by a G-slatistic; and the mean| standard deviation| skewness| and kurtosis of body mass. Simple and liberal statistical analyses fail to show any consistent relationship between any two isotope and mammalian time series| other than some unavoidable correlations between a few untransformed| highly autocorrelated time series like the raw isotope and mean body mass curves. Standard methods of detrending and differencing remove these correlations. Some of the major climate shifts indicated by oxygen isotope records do correspond to major ecological and evolutionary transitions in the mammalian biota| but the nature of these correspondences is unpredictable| and several other such transitions occur at times of relatively little global climate change. We conclude that given currently available climate records| we cannot show that the impact of climate change on the broad patterns of mammalian evolution involves linear forcings; instead| we see only the relatively unpredictable effects of a few major events. Over the scale of the whole Cenozoic| intrinsic| biotic factors like logistic diversity dynamics and within-lineage evolutionary trends seem to be far more important. 3074,2000,3,4,Global climate change and the effect of conservation practices in US agriculture,The use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This| in turn| will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual| site-specific conservation practices on changes in soil organic carbon. There is a general absence| however. of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage| the Conservation Reserve Program| and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices| it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million Mt. By 2008| there will be an increase of about 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration| there are a number of policy options that can be pursued. These include education and technical assistance| financial assistance| research and development| land retirement| and regulation and taxes. (C) 2000 Published by Elsevier Science Ltd. 3057,2000,3,3,Global climate change and the effect of conservation practices in US agriculture,Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This| in turn| will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual| site-specific conservation practices on changes in soil organic carbon. There is a general absence| however| of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage| the Conservation Reserve Program| and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices| it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million metric tons. By 2008| there will be an increase of about 25%. Given that there is a significant potential for conservation practices| which could lead to an increase in carbon sequestration| there are a number of policy options that can be pursued. These include education and technical assistance| financial assistance| research and development| land retirement| and regulation and taxes. 3100,2000,4,4,Global climate change and the precautionary principle,The precautionary principle is promoted as a common sense approach that avoids unreasonable delays in taking action. A weak form of the precautionary principle| that action should not wait until all uncertainties are resolved| is indeed common sense and consistent with even the most elementary application of the methods of decision making under uncertainty to the climate change problem. The standard tools of decision analysis imply conclusions consistent with a weak precautionary principle of taking some action before all the evidence is in. Decision theory also reveals what the basis is for stronger recommendations from the precautionary principle| to the effect that action should be based on the most pessimistic possible interpretation of the future. This conclusion is only possible if prior beliefs are so pessimistic and so strong that they would outweigh any possible new scientific evidence. 3099,2000,3,3,Global climate change: Benefit-cost analysis vs. the precautionary principle,The precautionary principle appears to be directly applicable to the prospect that human activities will cause substantial changes to global climate. The magnitude and characteristics of the change in climate and its effects on human activities and unmanaged ecosystems are highly uncertain| potentially catastrophic| and nearly irreversible on human time scales. Nevertheless| the precautionary principle adds little to benefit-cost analysis for evaluating climate policies. Benefit-cost analysis can incorporate aversion to uncertainty about future outcomes| and also provides a method for balancing this concern against concern for uncertain near-term policy costs. The policies favored by setting constraints on future outcomes| such as atmospheric stabilization and tolerable windows| may be less precautionary than the policies favored by benefit-cost analysis| as benefit-cost analysis can more readily accommodate concerns for moderate as well as severe harms. Concerns about possible climate catastrophes can also be incorporated in benefit-cost analysis and| in any event| may have limited implicatioms for policy choice. 3090,2000,2,2,Global model of vegetation migration: incorporation of climatic variability,Climate change induced by increasing concentrations of greenhouse gases in the atmosphere is expected to transform global distribution of terrestrial vegetation. The analysis of global vegetation distributions determined by earth's climates is usually based on biogeographical classifications. These classifications assume that flora in any location is predetermined by certain parameters of climate| and that change in these parameters will produce instant changes in plants composition. Application of the models employing biogeographical classifications to different scenarios of climate change is generally limited with the hypothesis of 'dynamic equilibrium': the rate of climate change should be comparable with the rate of vegetation response. The estimated rate of hypothesized global warming is now considered to be fast enough to fall outside these limits. Therefore| an alternative assumption that the forests will be extirpated| but will not migrate to the new territory within the time limits of CO| doubling| can be considered a better approximation of future vegetation dynamics. We propose a model to study the effect of native variability of input data on model prediction| portraying vegetation migration as a stochastic process. We included into analysis only variability of climate and assumed that the only process affected by changing climate variability is vegetation mortality (i.e. regional extirpation). Our simulations show that the probabilistic approach can significantly change the forecasts of global vegetation redistribution. The predicted by the model extirpation area for boreal forests is significantly less| than the area predicted by the equilibrium model without forest in-migration. (C) 2000 Elsevier Science B.V. All rights reserved. 5151,2000,2,2,Global warming,What is the relationship between the warming of global climate and the frequency and intensity of extreme regional or local weather events| events that largely govern the perceived and realized impact of climate or climate change on society and environment? Are such events intrinsically more likely or more severe as climate warms? Can the occurrence of such events be used as evidence for a changing climate| or even a changing climate induced by rising greenhouse gas concentrations? These are questions that have been increasingly asked over the last few years as the public awareness of extreme weather events has increased| and their often dramatic impacts have been captured on video footage. Changes in climate and its temporal variability clearly have implications for the frequencies and characteristics of extreme weather events such as heatwaves| severe winter cold| drought and intense precipitation episodes. The prospect of climate change| at least partly induced by human activities| therefore raises concerns about the changing frequencies with which extreme weather events may occur in the future. Whilst the sensitivity of extreme events to a change in mean climate or its temporal variability has been recognized in principle for many years (e.g.| Mearns et al.| 1984; Wigley| 1985)| it is only quite recently that extensive analyses of changing extreme event frequencies using either observational climate data or model-based simulations of future climate have been conducted. For example| the Intergovernmental Panel on Climate Change (IPCC)| in their Second assessment report| concluded just four years ago that ‘. . . the evidence that extreme weather events have increased in a global sense through the twentieth century| is [limited because] data and analyses are poor and not comprehensive’ (Nicholls et al.| 1996: 173).
5275,2000,3,4,Global warming - facts| assessment| countermeasures,Global primary energy consumption amounts to 8.38 billion tonnes oil equivalent (OE) (1996) and is projected to increase by 1.3% per year for the industrialized countries and by up to 9.2% per year for the developing countries. Fossil energy's share was 7.541 billion tonnes OE in 1996 with rising tendency. The order of magnitude of proved reserves of fossil energy sources is 950 billion tonnes OE (1996)| and certain present probable and possible reserves will become proved ones in the years to come. Fossil energy will| therefore| remain the number one energy source until far into the next century. The use of fossil energy produced 23.8 billion tonnes of carbon dioxide (CO2) in 1996 with oil and gas contributing about 60% to this figure. It is estimated that continued use of fossil energy will lead to an increase of the average global temperature by 1.0-3.5 degrees C in the coming 50-100 years. Though the forecasts of future CO2 emissions from fossil energy use as well as the magnitude of their influence on global warming are much disputed| the impact of CO2-emissions on global warming itself is widely admitted. There is much dissense on the climatic consequences of global warming. It cannot be ruled out| however| that these consequences may be detrimental to mankind. This has in a sense of a "no regret policy" triggered substantial activity worldwide to decrease emission of greenhouse gases| especially of CO2| and various attempts have been made to set binding limits for the emission of these gases. The harmonized worldwide implementation of CO2-reduction strategies is| however| far from being realized. OECD-countries have made substantial progress in applying these strategies. Nevertheless| the contribution of the industrialized countries to worldwide GO-emissions is still over-proportionally large. The cost of developing and applying CO2-reduction technologies are tremendous and prohibitive for most of the emerging economies. There is an obligation of the industrialized countries in their own interest to develop and make available these technologies wherever they are needed. The cost/efficiency ratio of CO2-reduction measures must be a decisive criterion for their application. There are serious obstacles| though| to reducing CO2-emissions while satisfying the energy needs of our world| e.g. lacking international harmonization| national needs and egoisms| rapid growth of world population and strongly increasing energy demand of emerging economies. In summing up| though an anthropogenic contribution to global warming cannot be proved for the time bring| it cannot be ruled out forever. Therefore| internationally harmonized measures for CO2-reduction have to be taken in the sense of a "no regret policy" to avert potential damage from mankind and| thus| contribute in this sense to a sustainable development with fossil energy. (C) 2000 Elsevier Science B.V. All rights reserved. 5207,2000,2,4,Global warming and avian occupancy of hot deserts; a physiological and behavioral perspective,Avian adjustments to desert environments are characterized by an integration of behavior and physiology. These responses serve to maintain homeostasis and conserve vital resources such as water. The small size of birds confers a close coupling to the thermal environment and demands rapid adjustments to environmental challenges. Physiological responses to heat stress include hyperthermia| and increased evaporative cooling as environmental temperatures approach body temperature. Behaviorally| desert birds respond to heat stress by drastically reducing activity during the hottest parts of the day and selecting cool shaded microsites. This characteristic behavioral response presents a potential problem in the face of global warming. If birds totally forgo foraging during extremely hot periods| increased evaporative water loss rates due to higher environmental temperatures could lead to significant episodes of direct mortality for birds in these regions. A simple model is presented which integrates behavior and physiology to predict survival times based on dehydration tolerance| microsite selection and environmental temperature. 5185,2000,2,4,Global warming and terrestrial ecosystems: A conceptual framework for analysis,ECOSYSTEM RESPONSES TO GLOBAL WARMING WILL BE COMPLEX AND VARIED. ECOSYSTEM WARMING EXPERIMENTS HOLD GREAT POTENTIAL FOR PROVIDING INSIGHTS ON WAYS TERRESTRIAL ECOSYSTEMS WILL RESPOND TO UPCOMING DECADES OF CLIMATE CHANGE. DOCUMENTATION OF INITIAL CONDITIONS PROVIDES THE CONTEXT FOR UNDERSTANDING AND PREDICTING ECOSYSTEM RESPONSES.
5241,2000,4,3,Global warming and tropical land-use change: Greenhouse gas emissions from biomass burning| decomposition and soils in forest conversion| shifting cultivation and secondary vegetation,Tropical forest conversion| shifting cultivation and clearing of secondary vegetation make significant contributions to global emissions of greenhouse gases today| and have the potential for large additional emissions in future decades. Globally| an estimated 3.1x10(9) t of biomass carbon of these types is exposed to burning annually| of which 1.1x10(9) t is emitted to the atmosphere through combustion and 49x10(6) t is converted to charcoal (including 26-31x10(6) t C of black carbon). The amount of biomass exposed to burning includes aboveground remains that failed to burn or decompose from clearing in previous years| and therefore exceeds the 1.9x10(9) t of aboveground biomass carbon cleared on average each year. Above- and belowground carbon emitted annually through decomposition processes totals 2.1x10(9) t C. A total gross emission (including decomposition of unburned aboveground biomass and of belowground biomass) of 3.41x10(9) t C year(-)1 results from clearing primary (nonfallow) and secondary (fallow) vegetation in the tropics. Adjustment for trace gas emissions using IPCC Second Assessment Report 100-year integration global warming potentials makes this equivalent to 3.39x10(9) t of CO(2)-equivalent carbon under a low trace gas scenario and 3.83x10(9) t under a high trace gas scenario. Of these totals| 1.06x10(9) t (31%) is the result of biomass burning under the low trace gas scenario and 1.50x10(9) t (39%) under the high trace gas scenario. The net emissions from all clearing of natural vegetation and of secondary forests (including both biomass and soil fluxes) is 2.0x10(9) t C| equivalent to 2.0-2.4x10(9) t of CO(2)-equivalent carbon. Adding emissions of 0.4x10(9) t C from land-use category changes other than deforestation brings the total for land-use change (not considering uptake of intact forest| recurrent burning of savannas or fires in intact forests) to 2.4x10(9) t C| equivalent to 2.4-2.9x10(9) t of CO(2)-equivalent carbon. The total net emission of carbon from the tropical land uses considered here (2.4x10(9) t C year(-)1) calculated for the 1981-1990 period is 50% higher than the 1.6x10(9) t C year(-)1 value used by the Intergovernmental Panel on Climate Change. The inferred (= `missing') sink in the global carbon budget is larger than previously thought. However| about half of the additional source suggested here may be offset by a possible sink in uptake by Amazonian forests. Both alterations indicate that continued deforestation would produce greater impact on global carbon emissions. The total net emission of carbon calculated here indicates a major global warming impact from tropical land uses| equivalent to approximately 29% of the total anthropogenic emission from fossil fuels and land-use change. 5224,2000,4,3,Global warming in the twenty-first century: An alternative scenario,A common view is that the current global warming rate will continue or accelerate| But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs)| such as chlorofluorocarbons| CH4. and N2O| not by the products of fossil fuel burning| CO2 and aerosols| the positive and negative climate forcings of which are partially offsetting. The growth rate of non-CO2 GHGs has declined in the past decade. If sources of CH4 and O-3 precursors were reduced in the future| the change in climate forcing by non-CO2 GHGs in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions| this reduction of non-CO2 GHGs could lead to a decline in the rate of global warming| reducing the danger of dramatic climate change. Such a focus on air pollution has practical benefits that unite the interests of developed and developing countries. However| assessment of ongoing and future climate change requires composition-specific long-term global monitoring of aerosol properties. 5323,2000,3,4,Global warming potential assessment for CF3OCF=CF2,We have examined CF3OCF = CF2 regarding its reactivity toward OH radical| its infrared spectroscopic properties| its atmospheric lifetime| and its radiative forcing. From these we then determined the Global Warming Potentials (GWPs) for CF3OCF = CF2. The examination is completed using a combination of discharge flow coupled with mass spectrometer and resonance fluorescence (DF/MS/RF)| Fourier transform infrared (FTIR) spectroscopy| ab initio molecular orbital calculation| and atmospheric and radiative transfer modeling. Mass spectral evidence suggests that both HF and CF3OCFC(O)F are products from the reaction of CF3OCF = CF2 with OH. The Arrhenius expression for CF3OCF = CF2 + OH is determined to be k(1) = (6.41 +/- 0.82) x 10(-11) exp[(-868 +/- 40)/T] cm(3) molecule(-1) s(-1) in the temperature range of 253-348 K. The atmospheric lifetime of CF3OCF = CF2 is estimated to be less than 5 days due to the OH attack. The calculated vibrational frequencies using ab initio molecular orbital calculations are in good agreement with FTIR experimental observation for the CF3OCF = CF2 molecule. Both C-O and C-F stretching modes in the CF3OCF = CF2 contribute to prominent absorption in the atmospheric window region. The absolute adjusted radiative forcing at the tropopause due to an increase in the concentration of CF3OCF = CF2 by one part per billion by volume (ppbv) is calculated to be 0.041 W m(-2) ppbv(-1). The Global Warming Potential for CF3OCF = CF2 is evaluated to be 0.004 for 100-year time horizon. 5307,2000,3,2,Global warming potentials: 1. Climatic implications of emissions reductions,The use of Global Warming Potentials (GWPs) to calculate 'equivalent' carbon dioxide emissions reductions in the climate change context is examined. We find that GWPs are accurate only for short time horizons. Over long time horizons their use implicitly leads to tradeoffs between near-term and long-term climate change. For one of the most policy-relevant cases| comparing reductions in methane and carbon dioxide| the long-term effect on climate of reducing methane emissions is relatively small| at variance with the common perception based on published GWP values. 5308,2000,4,4,Global warming potentials: 2. Accuracy,This paper exposes flaws in the mathematical structure of the Global Warming Potential (GWP) concept. These lead to errors when emissions changes in different greenhouse gases are compared. The most fundamental problem is that the unit impulse response functions from which GWPs| and many of their proposed alternatives| are constructed provide an incomplete representation of the relationship between emissions and radiative forcing. Additional errors occur when GWPs are used to compare finite-length emissions changes. 5172,2000,4,4,Global warming: Evidence from satellite observations,Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer| flown onboard sequential| sun-synchronous| polar-orbiting NOAA operational satellites| indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study| we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm-blackbody temperature| which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically-weighted global-mean temperature of the atmosphere| with a peak weight near the mid troposphere| warmed at the rate of 0.13+/-0.05 Kdecade(-1) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite-deduced result. 3150,2000,3,4,Greenhouse gas emissions in Hong Kong,This study provides a quantitative review of the emissions of carbon dioxide (CO2) and methane (CH4)| the two most significant greenhouse gases (GHGs) in Hong Kong. Study indicated that CO2 accounts for 90% of the local GHG emissions in Hong Kong. Among the different typos of fuels coal is identified as the major source of CO2| which constitutes about 50% by fuel type. On the other hand| CH4| which mainly comes from waste decomposition| contributes to 5% of the total GHG emissions. Correlation study revealed that energy consumption and waste quantity were strongly correlated with population and gross domestic products (GDP)| implying that not much has been done in Hong Kong to re-mediate GHG emissions. Regression analysis concluded that supply side management (fuel switch) was more effective than demand side management (energy conservation) in mitigating CO2 emissions in Hong Kong. (C) 2000 Elsevier Science Ltd. All rights reserved. 5356,2000,3,2,Greenhouse gases and other airborne pollutants from household stoves in China: a database for emission factors,Emissions from household stoves| especially those using solid fuels. can contribute significantly to greenhouse gas (GHG) inventories and have adverse health impacts. Few data are available on emissions from the numerous types of cookstoves used in developing countries. We have systematically measured emissions from 55 fuel/stove combinations in India and China| a large fraction of the combinations in use world-wide. A database was generated containing emission factors of direct and indirect GHGs and other airborne pollutants such as CO2| CO| CH4| TNMHC| N2O| SO2| NOx| TSP| etc. In this paper| we report on the 28 fuel/stove combinations tested in China. Since fuel and stove parameters were measured simultaneously along with the emissions| the database allows construction of complete carbon balances and analyses of the trade-off of emissions per unit fuel mass and emissions per delivered energy. Results from the analyses show that the total emissions per unit delivered energy were substantially greater from burning the solid fuels than from burning the liquid or gaseous fuels| due to lower thermal and combustion efficiencies for solid-fuel/stove combinations. For a given biomass fuel type| increasing overall stove efficiency tends to increase emissions of products of incomplete combustion. Biomass fuels are typically burned with substantial production of non-CO2 GHGs with greater radiative forcing| indicating that biomass fuels have the potential to produce net global warming commitments even when grown renewably. (C) 2000 Elsevier Science Ltd. All rights reserved. 5202,2000,3,4,Greenhouse gases in intensive agriculture: Contributions of individual gases to the radiative forcing of the atmosphere,Agriculture plays a major role in the global fluxes of the greenhouse gases carbon dioxide| nitrous oxide| and methane. From 1991 to 1999| we measured gas fluxes and other sources of global warming potential (GWP) in cropped and nearby unmanaged ecosystems. Net GWP (grams of carbon dioxide equivalents per square meter per year) ranged from 110 in our conventional tillage systems to -211 in early successional communities. None of the annual cropping systems provided net mitigation| although soil carbon accumulation in no-till systems came closest to mitigating all other sources of GWP. In all but one ecosystem| nitrous oxide production was the single greatest source of GWP. In the Late successional system| GWP was neutral because of significant methane oxidation. These results suggest additional opportunities for Lessening the GWP of agronomic systems. 5201,2000,2,4,Heat related mortality in warm and cold regions of Europe: observational study,Objectives To assess heat related mortalities in relation to climate within Europe. Design Observational population study. Setting North Finland| south Finland| Baden-Wurttemberg| Netherlands| London| north Italy| and Athens. Subjects People aged 65-74. Main outcome measures Mortalities at temperatures above| below and within each region's temperature band of minimum mortality. Results Mortality was lowest at 14.3-17.3 degrees C in north Finland but at 22.7-25.7 degrees C in Athens. Overall the 3 degrees C minimum mortality temperature bands were significantly higher in regions with higher than lower mean summer temperatures (P = 0.027). This was not due to regional differences in wind speeds| humidity| rain. As a result| regions with hot summers did not have significantly higher annual hear related mortality per million population than cold regions at temperatures above these bands. Mean annual heat related mortalities were 304 (95% confidence interval 126 to 482) in North Finland| 445 (59 to 831) in Athens| and 40 (13 to 68) in London. Cold related mortalities were 2457 (1130 to 3786)| 2533 (965 to 4101)| and 3129 (2319 to 3939) respectively. Conclusions Populations in Europe have adjusted successfully to mean summer temperatures ranging from 13.5 degrees C to 24.1 degrees C| and can be expected to adjust to global warming predicted for the next half century with little sustained increase in heat related mortality. Active measures to accelerate adjustment to hot weather could minimise temporary rises in heat related mortality| and measures to maintain protection against cold in winter could permit substantial reductions in overall mortality as temperatures rise.
5176,2000,3,3,High density plasma oxide etching using nitrogen trifluoride and acetylene,The use of nitrogen trifluoride (NF3) and acetylene (C2H2) in the presence of helium has been examined fur oxide etching in an inductively coupled| high density plasma etch tool. Oxide etch rates have been measured for blanket films and For patterned wafers with features of 0.6| 0.45| and 0.35 mum nominal critical dimension| while process performance has been assessed with cross-sectional scanning electron microscopy. Optical emission spectroscopy has been employed in situ to characterize the species present in the plasma| and quadrupole mass spectrometry has been used to analyze process affluent sampled between the chamber outlet and the turbo pump inlet. Polymer film deposited on the surface of the oxide layer has been studied with time-of-flight secondary ion mass spectrometry. Global warming emissions for a range of process conditions have been quantified using Fourier transform infrared spectroscopy| and are compared to emissions from more typical oxide etch processes on the same tool type. Results indicate that the NF3/C2H2 chemistry is capable of etching oxide anisotropically| while offering a significantly lower global warming impact than current oxide etch chemistries. (C) 2000 American Vacuum Society. [S0734-2101(00)00306-7]. 5250,2000,3,4,High photosynthetic productivity of green microalga Chlorella sorokiniana,The batch culture of a newly isolated strain of a green microalga| Chlorella sorokiniana| was carried out using a conical helical tubular photobioreactor. The isolate was capable of good growth at 40 degrees C under an airstream enriched with 10% CO2. The maximum photosynthetic productivity was 34.4 g of dry biomass/(m(2) of installation area . d) (12-h light/12-h dark cycle) when the cells were illuminated with an average photosynthetic photon flux density (photosynthetically active radiation ([PAR] 400-700 nm) simulating the outdoors in central Japan (0.980 mmol photons/[m(2).s]). This corresponded to a photosynthetic efficiency of 8.67% (PAR)| which was defined as the percent age of the light energy recovered as biomass (394 kJ/[reactor.d]) to the total light energy received (4545 kJ/[reactor.d]). A similarly high photosynthetic efficiency (8.12% [PAR]) was also attained in the combined presence of 10% CO2| 100 ppm of NO| and 25 ppm of SO2. Moreover| good photosynthetic productivity was also obtained under high temperature and high light intensity conditions (maximum temperature| 46.5 degrees C; 1.737 mmol photons/ [m(2).s])| when simulating the strong irradiance of the midday summer sun. This strain thus appears well suited for practical application for converting CO2 present in the stack gases emitted by thermal power plants and should be feasible even during the hot summer weather. 5152,2000,4,4,High-resolution Fourier transform and diode-laser spectroscopy of the nu(6) fundamental of C2F6 and associated hot bands,High-resolution infrared spectra of the upsilon (6) (713 cm(-1)) band region of C2F6 vapor have been recorded at several temperatures. Spectra at 77| 200| and 300 K were recorded using a Fourier transform spectrometer with unapodized resolutions of 0.0018 cm(-1) (200 and 300 K)and 0.008 cm(-1) (77 K). Spectra with rotational temperatures in the range 5-50 K were recorded in a supersonic jet using diode-laser absorption spectroscopy. The upsilon (6) band contains two clear sequences of hot-bands: one arises from the upsilon (4) torsional vibration at 67.5 cm(-1); the other| shorter| weaker progression is built on the doubly degenerate upsilon (9) vibration at 220 cm(-1). They he to high and low wavenumbers of the fundamental band| respectively. Eleven series were assigned and fitted to these hot bands. A perturbed series in the upsilon (4) sequence is considered| by analogy with the infrared spectrum of C2H6 vapor| to be caused by an xy-Coriolis interaction either between 5 upsilon (4) and upsilon (9) + 2 upsilon (4) in the ground slate or| in the upper state| upsilon (6) + 5 upsilon (4) with upsilon (6) + upsilon (9) + 2 upsilon (4) or upsilon (6) + 5 upsilon (4) with 2 upsilon (8). One further series resolved only in the jet spectrum and lying very close to the fundamental is almost certainly due to the upsilon (6) fundamental of the isotopomer (CCF6)-C-13-C-12. (C) 2000 Academic Press. 5338,2000,3,2,High-volume fly ash system: Concrete solution for sustainable development,The challenge for the civil engineering community in the near future will he to realize projects in harmony with the concept of sustainable development| and this involves the use of high-performance materials produced at reasonable cost with the lowest possible environmental impact. Portland cement concrete is a major construction material worldwide. Unfortunately| the production of portland cement releases large amounts of CO(2) into the atmosphere| and because this gas is a major contributor to the greenhouse effect and the global warming of the planet| the developed countries are considering very severe regulations and limitations on the CO(2) emissions. In view of the global sustainable development| if is imperative that supplementary cementing materials be used to replace large proportions of cement in the concrete industry| and the mob available supplementary cementing material worldwide is fly ash| a by-product of thermal power stations. To considerably increase the utilization of fly ash that ts otherwise being wasted| and to have a significant impact on the production of cement| it is necessary to advocate the use of concrete that will incorporate large amounts of fly ash as a replacement for cement. Such concrete| however| must demonstrate performance comparable to that of conventional portland cement concrete| and must be cost effective. In 1985| CANMET developed a concrete incorporating large volumes of fly ash that has all the attributes of high-performance concrete| that is| one that has excellent mechanical properties| low permeability superior durability| and that is environmentally friendly. This paper gives an overview of the properties of this type of concrete that is believed to be a very promising alternative for the industry seeking to meet the sustainable development objectives. 5235,2000,5,4,Holocene climate in the western Great Lakes national parks and lakeshores: Implications for future climate change,We reconstruct Holocene climate history (last 10|000 years) for each of the U.S. National Park Service units in the western Great Lakes region in order to evaluate their sensitivity to global warming. Annual precipitation| annual temperature| and July and January temperatures were reconstructed by comparing fossil pollen in lake sediment with pollen in surface samples| assuming that ancient climates were similar to modern climate near analogous surface samples. In the early Holocene| most of the parks experienced colder winters| warmer summers| and lower precipitation than today. An exception is Voyageurs National Park in northern Minnesota where| by 8000 years ago| January temperatures were higher than today. The combination of high mean annual temperature and lower precipitation at Voyageurs resulted in a dry period between 8000 and 5000 years ago| similar to the Prairie Period in regions to the south and west. A mid-Holocene warm-dry period also occurred at other northern and central parks but was much less strongly developed. In southern parks there was no clear evidence of a mid-Holocene warm-dry period. These differences suggest that global model predictions of a warm| dry climate in the northern Great Plains under doubled atmospheric CO2 may be more applicable to Voyageurs than to the other parks. The contrast in reconstructed temperatures at Voyageurs and Isle Royale indicates that the ameliorating effect of the Great Lakes on temperatures has been in effect throughout the Holocene and presumably will continue in the future| thus reducing the potential for species loss caused by future temperature extremes. Increased numbers of mesic trees at all of the parks in the late Holocene reflect increasing annual precipitation. This trend toward more mesic conditions began 6000 years ago in the south and 4000 years ago in the north and increased sharply in recent millennia at parks located today in lake-effect snow belts. This suggests that lake-effect snowfall is sensitive to continental-scale changes in climate and could be affected by future climate change. Plant and animal species sensitive to changes in the moisture regime could thus be endangered within the Great Lakes parks. 5357,2000,5,4,Holocene glacier fluctuations: is the current rate of retreat exceptional?,Most glaciers in the Northern Hemisphere reached their postglacial maximum in recent times| that is| after the medieval period. During the last 100 or 150 years a significant retreat has taken place| and there is little sign that this is coming to an end. The current worldwide shrinkage of glaciers is considered to be a strong indication of global warming. However| glacier retreat should be judged against the natural variability of glacier systems. Numerical glacier models can be used to quantify this variability. I have studied the natural variability of three glaciers for which long historic records of glacier length exist: Nigardsbreen| Norway; Rhonegletscher| Switzerland; and FranzJosefGlacier| New Zealand. Integrations for a 10 000 year period| driven by random forcing of a realistic strength| show that the current retreat cannot be explained from natural variability in glacier length and must be due to external forcing. 3143,2000,5,4,How well can we simulate past climates? Evaluating the models using global palaeoenvironmental datasets,Global syntheses of palaeoenvironmental data are required to test climate models under conditions different from the present. Data sets for this purpose contain data from spatially extensive networks of sites. The data are either directly comparable to model output or readily interpretable in terms of modelled climate variables. Data sets must contain sufficient documentation to distinguish between raw (primary) and interpreted (secondary| tertiary) data| to evaluate the assumptions involved in interpretation of the data| to exercise quality control| and to select data appropriate for specific goals. Four data bases for the Late Quaternary| documenting changes in lake levels since 30 (14)C kyr BP (the Global Lake Status Data Base)| vegetation distribution at 18 (14)C kyr and 6 (14)C kyr BP (BIOME 6000)| aeolian accumulation rates during the last glacial-interglacial cycle (DIRTMAP)| and tropical terrestrial climates at the Last Glacial Maximum (the LGM Tropical Terrestrial Data Synthesis) are summarised. Each has been used to evaluate simulations of Last Glacial Maximum (LGM: 21 calendar kyr BP) and/or mid-Holocene (6 cal. kyr BP) environments. Comparisons have demonstrated that changes in radiative forcing and orography due to orbital and ice-sheet variations explain the first-order| broad-scale (in space and time) features of global climate change since the LGM. However| atmospheric models forced by 6 cal. kyr BP orbital changes with unchanged surface conditions fail to capture quantitative aspects of the observed climate| including the greatly increased magnitude and northward shift of the African monsoon during the early to mid-Holocene. Similarly| comparisons with palaeoenvironmental datasets show that atmospheric models have underestimated the magnitude of cooling and drying of much of the land surface at the LGM. The inclusion of feedbacks due to changes in ocean- and land-surface conditions at both times| and atmospheric dust loading at the LGM| appears to be required in order to produce a better simulation of these past climates. The development of Earth system models incorporating the dynamic interactions among ocean| atmosphere| and vegetation is therefore mandated by Quaternary science results as well as climatological principles. For greatest scientific benefit| this development must be paralleled by continued advances in palaeodata analysis and synthesis| which in turn will help to define questions that call for new focused data collection efforts. (C) 1999 Elsevier Science Ltd. All rights reserved. 5253,2000,4,2,Identifying key sources of uncertainty in climate change projections,What sources of uncertainty should be included in climate change projections and what gains can be made if specific sources of uncertainty are reduced through improved research? DIALOGUE| an integrated assessment model| has been used to answer these questions. Central in the approach of DIALOGUE is the concept of parallel modeling| i.e.| for each step in the chain from emissions to climate change a number of equivalent models are implemented. The following conclusions are drawn: The key source of uncertainty in global temperature projections appears to be the uncertainty in radiative forcing models. Within this group of models uncertainty within aerosol forcing models is about equal to the total forcing of greenhouse gas models. In the latter group CO2 is: dominant. The least important source of uncertainty appears to be the gas cycle models. Within this group of models the role of carbon cycle models is dominant. Uncertainty in global temperature projections has not been treated consistently in the literature. First| uncertainty should be calculated as a product of all uncertainty sources. Second| a particular choice of a base year for global warming calculations influences the ranking of uncertainty. Because of this| a comparison of ranking results across different studies is hampered. We argue that 'pre-Industrial' is the best choice for studies on uncertainty. There is a linear relationship between maximum uncertainty in the year 2100 and cumulative emissions of CO2 over the period 1990-2100: higher emissions lead to more uncertainty. 5192,2000,2,3,Impact of a climatic warming scenario on tree growth.,The climatic impact on tree radial growth resulting from an atmospheric CO2 doubling was studied for 24 populations of five tree species in the French Alps and the French Mediterranean area. The Arpege AGCM| which predicts a 3 degreesC increase in mean temperature and a light increase of precipitation| is used to estimate the climatic perturbation. The method is based on the integration of estimated climate in an empirical tree-ring to climate model| involving artificial neural networks. Only a few populations are sensitive to the climatic change; all are located on the boundaries of their ecological area and can be divided in two groups. The first one is composed of high altitude populations which show a growth increase induced by the warmer climate during the growing season. The second one| composed of a single Mediterranean Scots pine population| reacts with a severe growth reduction induced by the stronger water stress in summer. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS. 5327,2000,2,3,Impact of climate change on slope stability using expanded downscaling,Climate parameters affecting ground water and pore pressure fluctuations can| in many cases| trigger slope instability and hence landslide activity. Global warming due to the greenhouse effect and especially changes in precipitation patterns and air temperature might therefore have influences on future landslide activity. The present paper shows an assessment of climate change consequences for displacement rates of a mudslide in the Dolomites| Italy. The study is based on climate projections of a general circulation model (GCM). GCMs are able to successfully reproduce large-scale patterns of climate| while they show a poor performance on the regional scale. Therefore| GCM output is postprocessed with a statistical downscaling technique to derive local-scale climate change information from simulated atmospheric circulation patterns of the European-North Atlantic sector. The resulting precipitation and temperature series are introduced in a hydrological tank model| which calculates daily groundwater levels. Based on the groundwater data| a visco-plastic rheological model is applied to derive displacement rates of the mudslide as final output. The climate change signal is most pronounced for air temperature| while it is weaker but still significant for yearly precipitation| which is decreasing. As a consequence| yearly displacement rates show a significant reduction. The most dramatic changes| however| occur in spring with strongly lowered groundwater levels and consequently decreasing displacement rates. This is seen as an effect of reduced storage of winter precipitation as snow and hence decreasing meltwater amounts in early spring. The presented model chain with statistical downscaling| hydrological and rheological models allows the assessment of future landslide displacement affected by the greenhouse effect. The results| however| have to be taken with caution since in all parts of the model chain there are uncertainties that are difficult to address. (C) 2000 Elsevier Science B.V. All rights reserved. 3115,2000,2,4,Impact of global climate change on China's water resources,It is indicated that up to the year 2030| the annual average temperatures in China will increase by 0.88 to 1.2 degrees C| with increments in the south less than in the north. Annual average precipitation would raise slightly| but the increment could be 4% in northeastern China. The increment of annual mean runoff could rise over 6% in the northeastern area| and decrease in the other regions 1.4 to 10.5%. The increased water shortage due to climate change could achieve 160 to 5090 million m(3) in some areas of China. Financial loss due to the lack of water could reach 1300 million yuan| and up to 4400 million yuan in serious drought years in the Beijing-Tianjin-Tangshan area. 5319,2000,2,3,Impact of global warming on the Asian winter monsoon in a coupled GCM,The Asian winter monsoon (AWM) response to the global warming was investigated through a long-term integration of the transient greenhouse warming with the ECHAM4/OPYC3 CGCM. The physics of the response was studied through analyses of the impact of the global warming on the variations of the ocean and land contrast near the ground in the Asian and western Pacific region and the east Asian trough and jet stream in the middle and upper troposphere. Forcing of transient eddy activity on the zonal circulation over the Asian and western Pacific region was also analyzed. It is found that in the global warming scenario the winter northeasterlies along the Pacific coast of the Eurasian continent weaken systematically and significantly| and intensity of the AWM reduces evidently| but the AWM. variances on the interannual and interdecadal scales are not affected much by the global warming. It is suggested that the global warming makes the climate over the most part of Asia to be milder with enhanced moisture in winter. In the global warming scenario the contrasts of the sea level pressure and the near-surface temperature between the Asian continent and the Pacific Ocean become significantly smaller| northward and eastward shifts and weakening of the east Asian trough and jet stream in the middle and upper troposphere are found. As a consequence| the cold air in the AWM originating from the east Asian trough and high latitudes is less powerful. In addition| feedback of the transient activity also makes a considerable contribution to the higher-latitude shift of the jet stream over the North Pacific in the global warming scenario. 5341,2000,2,3,Impacts of climate warming on forests in Ontario: Options for adaptation and mitigation,This paper summarizes current knowledge about the optical properties of greenhouse gases and general climate-warming influences. It explains the influence of this new phenomenon on the major ecosystems of the world| and considers the process of deforestation. It then analyzes the warming trends in Ontario based on data from two weather stations with continuous records of more than 120 years| to determine the rate of warming in the Great Lakes-St. Lawrence Region. The results indicate a temperature increase of about 0.76 degrees C per century and an 8% increase in annual total precipitation. Current climate change models indicate that for a scenario of 2 x CO2 levels some general| probable prognoses can be made| including a temperature increase of up to 4.5 degrees C| which might be disastrous for existing forest ecosystems. Specifically| the consequences of climate warming on (a) northward shifts of ecological conditions| (b) forest productivity| and (c) forest physiology and health| are examined. In the context of global warming| the paper then recommends practical management measures necessary to ensure adaptation of existing forest ecosystems to the warming that is already developing. These measures are intended to provide a no-risk environment for existing forests until rotation age. Next| a wide range of mitigative measures is examined with a view to securing the longterm preservation of forest ecosystems to avoid major ecological disruptions and| gradually| to reverse climate warming. Application of these measures requires international consensus| but countries that apply these recommendations first have a chance to profit from them due to the "CO2 fertilization" effect. 3079,2000,2,4,Impacts of global climate change scenarios on water supply and demand in Jordan,The potential impact of global climate change is one of the least addressed factors in water resources planning in developing countries. The potential impacts of climate change are examined for Jordan| where a methodology is presented for improved management of water demand under the uncertainties associated with climate change. A temperature/precipitation sensitivity model is constructed and combined with water demand forecasts to project deficits for the year 2020. Deficit reducing options are then evaluated in terms of social and economic viability. The study concludes that only some of the deficits may be alleviated| illustrating the significance of considering climate change in planning for countries that already experience water imbalances. 5366,2000,3,3,Impacts of soil management on root characteristics of switchgrass,One approach to reducing the concentration of atmospheric carbon dioxide| which is a dominant greenhouse gas| is to develop renewable energy sources from biofuel crops. Switchgrass| (Panicum virgatum L.) as an energy crop| can partly mitigate potential global warming by supplementing fossil fuels and sequestering carbon (C). Although switchgrass grown for energy may impact C sequestration via the input of root biomass| information on the impact of soil management on switchgrass root growth is extremely limited. We determined the influence of row spacing| nitrogen (N) rate| switchgrass cultivar| and soil type on switchgrass root characteristics. Roots were mainly distributed in the surface soil (0-15 cm)| and were 90.4 and 68.2% of the total in the intrarow and interrow profile| respectively. Nitrogen application altered root N but not C concentration| implying that any increase in C sequestration by switchgrass roots will be due to increased root biomass rather than increased C concentration. Root weight density generally decreased in the interrow with wider row width| and N application generally did not affect root weight density. Root weight density in the Pacolet soil was higher than in the other four soils| and root density was 4.1 times higher in the Pacolet soil than in the Norfolk soil. Root mass in the Pacolet soil (36|327 kg ha(-1)) was 2.7 times greater than that found in the Norfolk soil (13|204 bg ha(-1)) within 150 cm of the soil surface. Differences in root characteristics were found among cultivars: root weight density with 'Cave-in-Rock' switchgrass was 29.4 and 47.6% higher than 'Alamo' and 'Kanlow'| respectively. Variations in switchgrass root biomass production owing to soil type and cultivar suggest that site and cultivar selection will be important determinants of C sequestration by switchgrass roots. A potential benefit of switchgrass is the reduced loss of nutrients associated with non-point pollution| owing to its deep root system that may extend 330 cm below the soil surface. (C) 2000 Elsevier Science Ltd. All rights reserved. 3139,2000,4,3,In situ respiration determination as tool for classifying soils according to soil organic matter content,Soil respiration is indicative of biological status of the soil and high respiration is correlated to high contents of available carbon (C) in soil and/or organic matter content. Because of soil respiration's relationship to soil organic matter status and content| soil respiration is considered one measurement that could aid in determining the quality of soil. In the global scale| the cycling of C in soil is important because the rise in CO2 in the atmosphere is linked to global climate change. In situ measurement of CO2 using instruments that are portable and perform analyses quickly are important to obtain sufficient number of measurements in the field to overcome spatial variability. Soil respiration tests were conducted in plots amended with fertilizer or organic amendments of agricultural or municipal residues since 1994. Besides CO2 moisture and temperature were measured over a period where the moisture varied from near saturation to below wilting point. It was found that flux was curvilinearly related to moisture from 5 to 40% (v/v). Maximum flux occurred for all plots between 30 and 40% saturation. The ratio of flux normalized by temperature to the volumetric soil moisture divided soils into two categories| those with soil organic matter (SOM) content above or below 4.5%. The determinations of CO2 flux| moisture and temperature uses equipment that is portable so that several sites in a field can be analyzed to reduce spatial variation. The only limitation is that the determinations must be performed on soils with less than 40% saturation or 25% moisture (v/v) because the normalized function is no longer linear above this moisture content. More than two SOM categories might be found if studies are expanded to soils with a wider range of SOM content. 5217,2000,5,4,Increased terrestrial carbon storage across the Palaeocene-Eocene boundary,A rapid| short-lived| global warming event at the close of the Palaeocene ca. 55.5 million years ago (Ma) was associated with the addition of massive amounts of carbon to the exogenic carbon cycle and major benthic extinctions. Evaluation of the response of the terrestrial biosphere to this transient ancient 'greenhouse' world with a process-based terrestrial carbon cycle model and global palaeoclimate simulations indicates the sequestration of ca. 1112 Gt C into the vegetation and soil carbon pools. A largely independent global carbon isotope mass balance analysis also points to the strong potential for the terrestrial biosphere to sequester substantial amounts of carbon at this time| with the increase being calculated at between 2107 and 3060 Gt C. This analysis suggests that some other feature of global environmental change across the Palaeocene-Eocene boundary may have been forcing terrestrial carbon cycle dynamics at this time. However| even a minimum increase of 1112 Gt C would have been sufficiently large to implicate the response of the terrestrial carbon cycle as a negative feedback mechanism on climate at 55.5 Ma| possibly reducing global temperatures by up to 2.5 degrees C. (C) 2000 Elsevier Science B.V. All rights reserved. 5227,2000,3,4,Inductively coupled plasmas in low global-warming-potential gases,Many high-density discharges used in microelectronics fabrication use fluorocarbon gases with coincidentally high global-warming potentials (GWPs). We have determined the identities| fluxes| and energy distributions of ions produced in high-density discharges generated in two low GWP gases| CF3I and CF3CH2F (HFC-134a)| which have attracted interest for plasma processing applications. Measurements were made using a combined ion energy analyser-mass spectrometer that samples ions through an orifice in the lower electrode of an inductively coupled Gaseous Electronics Conference (GEC) rf reference cell. The effects of plasma operating conditions and Ar dilution on ion fluxes and energies were examined. Nearly complete dissociation of CF3I occurs in CF3I discharges and I+ comprises almost all of the ion yield. Mean ion energies range from 5 eV to 10 eV for the operating conditions investigated. Discharges generated in mixtures of CF3I with Ar have ion fluxes and energies resembling those in pure CF3I discharges. Pure HFC-134a discharges produce several ions of significant intensity| with HF+ and Si+ bring the most abundant. Mean ion energies range from 20 eV to 35 eV| and decrease as HFC-134a is diluted with Ar. Higher discharge powers result in greater dissociation in HFC-134a discharges| shifting the ion composition towards higher fluxes of lighter ions. 5146,2000,2,4,Infection in the twenty-first century: predictions and postulates,The late Paul Garrod| in whose honour this lecture is named| was 'the right man at the right time'. He seized the opportunities offered by the dawning of the chemotherapeutic era with vigour and enthusiasm and was a formidable link between the traditional laboratory-based bacteriologist and the more clinically orientated 'modern' medical microbiologist. Professor Garrod was a founder member of the British Society for Antimicrobial Chemotherapy and I had the privilege of meeting him on many occasions. He would have relished the many challenges facing today's microbiologists| infectious disease physicians and public health experts. These wilt have major implications for antimicrobial chemotherapy in the twenty-first century. The emergence and prevalence of infectious diseases| and the necessity for discovering therapies to treat them| are influenced by many factors. In this lecture I will discuss four which could have a major influence on infectious diseases in the twenty-first century-global warming| biological warfare/terrorism| the dissemination of infections| including those caused by resistant pathogens| by travellers and certain untreatable zoonotic diseases. 3103,2000,2,4,Influence of N and non-N salts on atmospheric methane oxidation by upland boreal forest and tundra soils,The short-term (24h) and: medium-term (30 day) influence of N salts (NH4Cl| NaNO3 and NaNO2) and a non-N salt (NaCl) on first-order rate constants| k (h(-1)) and thresholds (C-Th) for atmospheric CH4 oxidation by homogenized composites of upland boreal forest and tundra soils was assessed at salt additions ranging to 20 mu mol g(-1) dry weight (dw) soil. Additions of NH4Cl| NaNO3 and NaCl to 0.5 mu mol g(-1) dw soil did not significantly decrease k relative to watered controls in the short term. Higher concentrations significantly reduced k| with the degree of inhibition increasing with increasing dose. Similar doses of NH4Cl and NaCl gave comparable decreases in k relative to controls and both soils showed low native concentrations of NH4+-N (less than or equal to 1 mu mol g(-1)dw soil)| suggesting that the reduction in k was due primarily to a salt influence rather than competitive inhibition of CH4 oxidation by exogenous NH4+-N or NH4+-N released through cation exchange. The decrease in k was consistently less for NaNO3 than for NH4Cl and NaCl at similar doses| pointing to a strong inhibitory effect of the Cl- counteranion. Thresholds for CH4 oxidation were less sensitive to salt addition than k for these three salts| as significant increases in C-Th relative to controls were only observed at concentrations greater than or equal to 1.0 mu mol g(-1) dw soil. Both soils were more sensitive to NaNO2 than to other salts in the short term| showing a significant decrease in k at an addition of 0.25 mu mol NaNO2 g(-1) dw soil that was clearly attributable to NO;. Soils showed no recovery from NaCl| NH4+-N or NaNO3 addition with respect to atmospheric CH4 oxidation after 30days. However| soils amended with NaNO2 to 1.0 mu mol NaNO2 g(-1) dw showed values of k that were not significantly different from controls. Recovery of CH4-oxidizing ability was due to complete oxidation of NO2--N to NO3--N. Analysis of soil concentrations of N salts necessary to inhibit atmospheric CH4 oxidation and regional rates of N deposition suggest that N deposition will not decrease the future sink strength of upland high-latitude soils in the atmospheric CH4 budget. 5149,2000,2,4,Influence of potential climate change on forest landscape dynamics of west-central Alberta,Changes in climatic conditions may influence both forest biomass accumulation rates and natural disturbance regimes. While changes in biomass accumulation of forests under various climatic conditions have been described by yield equations| large uncertainties exist with regard to disturbance regimes. Under the doubling carbon dioxide scenario| global warming impacts have been predicted from simulation results of the first generation of coupled global climate model (CGCMI). The calculated fine fuel moisture code (FFMC) distribution from the simulation results showed a one-point increase compared with the distribution under current climate conditions. The impact of predicted changes in FFMC distributions on fire disturbance patterns| forest volume| and landscape structure was investigated by using the spatially explicit model for landscape dynamics (SEM-LAND). The simulation results showed increases in fire disturbance frequency and decreases in forest volume. The simulations also showed decreases in landscape fragmentation and landscape diversity| whereas total availability of core habitat for wildlife increased. 5188,2000,2,4,Influence of spring warming on the predation rate of underyearling fish on Daphnia - a deterministic simulation approach,1. According to previous field studies in the biomanipulated Bautzen reservoir (Germany)| a midsummer decline of the dominating zooplankter| Daphnia galeata| was suggested to be initiated by a simultaneous occurrence of low fecundity of the daphnids and a selective feeding of underyearling fish on mature daphnids. The timing of both processes was assumed to be triggered by spring water temperature. However| the field data were not appropriate for testing whether yearly differences in spring warming are strong enough to control the predation rate of underyearling fish on daphnids. 2. By combining field data on fish growth| feeding and population mortality| the daily uptake of Daphnia by a virtual population of underyearling perch (Perca fluviatilis) was simulated| in addition| the daily predatory mortality of mature daphnids was calculated independently. Scenarios with a warm and a cold spring were compared. Furthermore| the delayed warming of a pelagic zone of a lake versus a littoral one was simulated. Sensitivity of the simulation to changes in five parameters was tested. 3. In both the warm spring scenario and the littoral warming scenario| more daphnids in general and more mature daphnids in particular were eaten| compared with the cold spring and pelagic scenarios. The predatory mortality of mature daphnids was driven by the increasing gape size of growing fish such that in warmer years the fish reach earlier the size at which they can eat mature daphnids. 4. The simulation was most sensitive to changes in daily mortality rate of the fish and to the size at maturity of the daphnids. Since at least the fish mortality is also temperature-dependent via the growth rates of fish| the predation rate of perch on D. galeata in Bautzen reservoir is substantially increased during a warm spring. This underlines the assumption that even a slight global warming may have a decisive influence on food web processes due to the fine-scaled patterns of trophic interactions in lakes. 5156,2000,2,3,Initial effects of experimental warming on above- and belowground components of net ecosystem CO2 exchange in arctic tundra,The Arctic contains extensive soil carbon reserves that could provide a substantial positive feedback to atmospheric CO2 concentrations and global warming. Evaluation of this hypothesis requires a mechanistic understanding of the in situ responses of individual components of tundra net ecosystem CO2 exchange (NEE) to warming. In this study| we measured NEE| total ecosystem respiration and respiration from below ground in experimentally warmed plots within Alaskan acidic tussock tundra. Soil warming of 2-4 degreesC during a single growing season caused strong increases in total ecosystem respiration and belowground respiration from moss-dominated inter-tussock areas| and similar trends from sedge-dominated tussocks. Consequently| the overall effect of the manipulation was to substantially enhance net ecosystem carbon loss during mid-summer. Components of vascular plant biomass were closely correlated with total ecosystem respiration and belowground respiration in control plots of both microsites| but not in warmed plots. By contrast| in the warmed inter-tussock areas| below ground respiration was most closely correlated with organic-layer depth. Warming in tussock areas was associated with increased leaf nutrient pools| indicating enhanced rates of soil nutrient mineralisation. Together| these results suggest that warming enhanced net ecosystem CO2 efflux primarily by stimulating decomposition of soil organic matter| rather than by increasing plant-associated respiration. Our short-term experiment provides field evidence to support previous growth chamber and modelling studies indicating that arctic soil C reserves are relatively sensitive to warming and could supply an initial positive feedback to rising atmospheric CO2 concentrations/changing climate. 5280,2000,3,4,Insights into the processing of carbon in the South Florida Cypress Wetlands: a whole-ecosystem approach using network analysis,Aim The aim of this research was to investigate the potential of the South Florida Cypress Wetlands as a carbon-accumulating system. Location This ecosystem is part of the Big Cypress Natural Preserve| located in the south-west part of Florida (USA) between the Mangrove Swamps that border the Gulf of Mexico and the Everglades. Methods This investigation was carried out by constructing networks of carbon exchange between the living and nonliving components that comprise this ecosystem. By means of these networks potential for carbon accumulation has been assessed by identifying and quantifying pathways for the transfer of carbon| assessing the efficiency between trophic levels| and evaluating the importance of material cycling. These analyses are commonly referred to as network analysis. Results Results obtained show that dependency on detritus by higher trophic levels is rather low and so is the trophic efficiency. Yet| less than 10% of the carbon that flows through the system is recycled and the magnitude of internal ascendency reaches only 40% of the total system ascendency. Main conclusions All these results support the hypothesis that the South Florida Cypress Wetlands are predominately flow-through in nature and that carbon accumulation in this environment is noticeable. 5216,2000,2,3,Intensified Asian summer monsoon and its variability in a coupled model forced by increasing greenhouse gas concentrations,The Asian summer monsoon response to global warming is investigated by a transient greenhouse warming integration with the ECHAM4/OPYC3 CGCM. It is demonstrated that increases of greenhouse gas concentrations intensify the Asian summer monsoon and its variability. The intensified monsoon results mainly from an enhanced land-sea contrast and a northward shift of the convergence zone. A gradual increase of the monsoon variability is simulated from year 2030 onwards. It seems to be connected with the corresponding increase of the sea surface temperature variability over the tropical Pacific. 5360,2000,2,3,Interactions between atmospheric CO2 enrichment and soil fauna,We have reviewed the responses of soil fauna to increased concentrations of atmospheric CO2 and the consequent climate change. These will affect several attributes of animal populations and communities including their density| biomass| diversity| activity| rates of consumption| life history parameters and migration ability. Changes in the quality and quantity of litter and global warming are the main factors which are expected to modify soil fauna. Although changes have been observed in several attributes of the soil fauna as a consequence of increased concentrations of atmospheric CO2| no general trend which might allow to the prediction of a general pattern of response has been identified. Because of the complexity of the biological mechanisms and the synergetic action of several factors| the few resulting responses reported in the literature are inconclusive. However| some aspects of the situation deserve more attention. These include the consequences of (1) changes in the food resources for soil fauna in the litter layer and in the rhizosphere| (2) the consumption of low quality litter by the macrofauna| (3) the change in life span in response to temperature elevation| (4) the enhancement of earthworm burrowing activity and (5) the changes in community composition arising because of specific differential resistance to adverse conditions. 3087,2000,2,4,Interactions of elevated CO2 and nitrogen fertilization: Effects on production of Bacillus thuringiensis toxins in transgenic plants,Elevated atmospheric CO2 concentrations will cause plants to grow faster| lower nitrogen content per unit of plant tissue| and generate higher carbon to nitrogen (C/N) ratios. We hypothesize that production of transgenic proteins will be reduced| thus reducing the efficiency of Bacillus thuringiensis (Bt) transgenes against insect populations. Commercially available transgenic cotton plants expressing the Cry 1Ac gene from Bt were compared with a near isogenic non-Bt cotton line in a split-plot design with two levels of atmospheric CO2 (ambient| 370 ppm and elevated| 900 ppm) incorporating a 2 X 2 factorial design with two nitrogen (N) fertilization regimes (low| 30 mg N/kg soil/wk and high| 130 mg N/kg soil/wk)|and two levels of Bt (presence or absence). Bioassays using Spodoptera exigua (Hubner) and quantitative enzyme-linked immunosorbent assays for toxin content indicated reduced Bt protein production in elevated CO2. The tendency for test insects to consume more foliage from plants with lower N| caused by the elevated CO2| did not compensate for the reduction in toxin production. N fertilization regime interacted with CO2 concentration| showing that plants growing in N limited systems would produce-substantially less toxin. The use of transgenic plants is becoming increasingly important and will continue to be so in the next decades. At the same time| atmospheric CO2 increase will affect the effectiveness of this strategy. These observations have implications not only for agricultural use of transgenic plants| but also for the ecological consequences of transfer of Bt toxins to closely related wild plant genotypes. 3125,2000,2,4,Interactive effects of atmospheric CO2 and soil-N availability on fine roots of Populus tremuloides,The objective of this experiment was to understand how atmospheric carbon dioxide (CO2) and soil-nitrogen (N) availability influence Populus tremuloides fine-root growth and morphology. Soil-N availability may limit the growth response of forests to elevated CO2 and interact with atmospheric CO2 to alter litter quality and ecosystem carbon (C) and N cycling. We established a CO2 x N factorial field experiment and grew six genotypes of P. tremuloides for 2.5 growing seasons in 20 large open-top chamber/root-box experimental units at the University of Michigan Biological Station in northern lower Michigan (USA). Ln this paper we describe an integrated examination of how atmospheric CO2 and soil-N availability influence fine-root morphology| growth| mortality| and biomass. We also studied the relationship between root biomass and total soil respiration. Over 80% of the absorbing root length of P. tremuloides was accounted fur by roots <0.4 mm in diameter| and specific root length(100-250 m/g) was much greater than reports for other temperate and boreal deciduous trees. Elevated atmospheric CO2 increased the diameter and length of individual roots. In contrast| soil N had no effect on root morphology. Fine-root length production and mortality| measured with minirhizotrons| was controlled by the interaction between atmospheric CO2 and soil N. Rates of root production and mortality were significantly greater at elevated CO2 when trees grew in high-N soil| but there were no CO2 effects at low soil N. Fine-root biomass increased 137-194% in high-N compared to low-N soil| and elevated atmospheric CO2 increased fine-root biomass (52%) in high soil N| but differences in low soil N were not significant. Across all treatments| dynamic estimates of net fine-root production were highly correlated with fine-root biomass (soil cores; r = 0.975). Mean rates of soil respiration were more than double in high-N compared to low-N soil. and elevated atmospheric CO2| when compared to ambient atmospheric CO2| increased mean rates of soil respiration 19% in 1995 and 25% in 1996. Across all treatments| total root biomass was linearly related to mean rates of soil respiration (r(2) = 0.96). Our results indicate that atmospheric CO2 and soil-N availability strongly interact to influence P. tremuloides fine-root morphology| growth| and C turnover. Aspen-dominated ecosystems of the future are likely to have greater productivity fueled by greater nutrient uptake due to greater root length production. Further| it appears that elevated atmospheric CO2 will result in greater C inputs to soil through greater rates of fine-root production and turnover| especially in high-fertility soils. Increased C inputs to soil result in greater rates of soil respiration. At this rime| it is not clear what effects increased rates of root turnover will have on C storage in the soil. 5196,2000,5,4,Intercomparison of coral oxygen isotope data and historical sea surface temperature (SST): Potential for coral-based SST field reconstructions,We examine the extent to which the large-scale features of the sea surface temperature (SST) anomaly field are represented by a sparse observational network of coral oxygen isotope (delta(18)O) time series. Regression of annually averaged delta(18)O data against gridded estimates of local SST anomaly within the period 1856-1990 confirm the literature regression of delta(18)O anomaly on SST anomaly for Indo-Pacific corals. However| while interannual SST variability is generally well represented by individual coral time series| observed decadal and secular variability does not always display a linear relationship to local SST anomaly. Instead| many records appear to better recover nonlocal| large-scale phenomena| which in turn are related to either the coral local SST or SST covariant changes in seawater delta(18)O. We employ empirical orthogonal function (EOF) analysis to identify common patterns of variability in the coral data. We find two significant patterns which are interpretable as the oceanographic signature of the El Nino-Southern Oscillation (ENSO) and as a near-global warming in which the eastern equatorial Pacific cools. A third pattern weakly resembles the Pacific Decadal Oscillation. These modes are seen more clearly in a singular Vector decomposition (SVD) of the covariance between the coral data and the dominant patterns of large-scale historical SST variability. The results are consistent with those found in EOF and SVD analyses of SST data from the coral locations. As additional coral-based proxy estimates become available| they will improve the resolution of the patterns recovered. These results suggest that a sparse network of coral data may be used to reconstruct interannual| secular| and decadal SST variability for preinstrumental periods| albeit with large uncertainty. 3055,2000,4,4,Intercomparison of shipboard and moored CARIOCA buoy seawater fCO(2) measurements in the Sargasso Sea,The ocean is an important sink for carbon and heat| yet high-resolution measurements of biogeochemical properties relevant to global climate change are being made only sporadically in the ocean at present. There is a growing need for automated| real-time| long-term measurements of CO2 in the ocean using a network of sensors| strategically placed oh ships| moorings| free-drifting buoys and autonomous remotely operated vehicles. The ground-truthing of new sensor technologies is a vital component of present and future efforts to monitor changes in the ocean carbon cycle and air-sea exchange of CO2. A comparison of a moored Carbon Interface Ocean Atmosphere (CARIOCA) buoy and shipboard fugacity of CO2 (fCO(2)) measurements was conducted in the western North Atlantic during two extended periods (> I month) in 1997. The CARIOCA buoy was deployed on the Bermuda Testbed Mooring (BTM)| which is located 5 km noah of the site of the US Joint Global Ocean Flux Study (JGOFS) Bermuda Atlantic Time-series Study (BATS). The high frequency of sampling revealed that temperature and fCO(2) responded to physical forcing by the atmosphere on timescales from diurnal to 4-8 days. Concurrent with the deployments of the CARIOCA buoy| frequent measurements of surface fCO(2) were made from the R/V Weatherbird II during opportunistic visits to the BTM and BATS sites| providing a direct calibration of the CARIOCA buoy fCO(2) data. Although| the in situ ground-truthing of the CARIOCA buoy was complicated by diurnal processes| sub-mesoscale and fine-scale variability| the CARIOCA buoy fCO(2) data was accurate within 3+/-6 mu atm of shipboard fCO(2) data for periods up to 50 days. Longer-term assessments were not possible due to the CARIOCA buoy breaking free of the BTM and drifting into waters with different fCO(2)-temperature properties. Strategies are put forward for future calibration of other in situ sensors. (C) 2000 Elsevier Science B.V. All rights reserved. 5161,2000,2,4,Interdecadal changes in the precipitation seasonal cycle over Southern South America and their relationship with surface temperature,The decadal variability in the structure of the annual precipitation cycle over Southern South America (SSA) is analysed with the purpose of investigating whether the lower frequency variability laid bare by annual data is also evident in the annual precipitation structure. Climatic analysis shows that the annual cycle plus the semi-annual cycle dominate the annual variability of precipitation in SSA and represent most of the physical factors responsible for the observed patterns. The percentage of variance explained by the annual cycle shows 2 local maxima| in northwestern Argentina and southern Chile| with opposite phases| summer and winter. The interdecadal analysis of the annual cycle shows 2 areas of relevant variability: one over the central east and the other over the north east. In the first area| there is a positive trend in the variance explained by the first harmonic| indicating that precipitation tends to be better represented by an annual cycle| a fact that might indicate a climatic change in so far as this variable is concerned. In view of global warming| and as a first step towards quantifying the relationship between temperature and precipitation in the region| correlation coefficients are evaluated. The correlation structure of the warmer period 1943-52 generally shows a slight correlation pattern when compared to the 2 colder periods| 1955-64 and 1966-75. In northwestern Argentina| the highest positive correlation coefficients are found at the coldest times in 1955-64| and are probably related to an increase in cloudiness. During summer months (November to February)| there is an inverse relationship between precipitation and temperature over most of SSA. That is| warmer/colder summers are associated with precipitation below/above the mean. In autumn and spring months| the correlation is positive in the eastern part of Argentina and Paraguay| and represents well the mechanism of maximum precipitation in this area| which is mainly the result of cyclogenesis. Winter correlation shows a weak positive pattern over SSA and a negative correlation area to the east of the Cordillera de los Andes| which is more intense in spring. 5372,2000,4,3,Interpretation of simulated global warming using a simple model,A simple energy balance model with two parameters| an effective heat capacity and an effective climate sensitivity| is used to interpret six CCM simulations of greenhouse gas-induced global warming. By allowing the parameters to vary in time| the model can be accurately calibrated for each run. It is found that the sensitivity can be approximated as a constant in each case. However the effective heat capacity clearly varies| and it is important that the energy equation is formulated appropriately| and thus unlike many such models. For simulations with linear forcing and from a cold start| the capacity is in each case close to that of a homogeneous ocean with depth initially 200 m| but increasing some 4.3 m each year irrespective of the sensitivity and forcing growth rate. Analytic solutions for this linear capacity function are derived| and these reproduce the GCM runs well| even for cases where the forcing is stabilized after a century or so. The formation of a subsurface maximum in the mean ocean temperature anomaly is a significant feature of such cases. A simple model for a GCM run with a realistic forcing scenario starting from 1880 is constructed using component results for forcing segments. Given this. an estimate of the cold start error of a simulation of the warming due to forcing after the present would be given by the negative of the temperature drift of the anomaly due to the past forcing. The simple model can evidently be used to give an indication of likely warming curves| at least for this range of scenarios and GCM sensitivities. 5197,2000,3,3,Inventory of emissions of greenhouse gases in Israel,As a Party to the United Nations Framework Convention on Climate Change| Israel is committed to develop a national inventory of anthropogenic emissions and removals of greenhouse gases. This paper presents the national inventory| which was developed according to the guidelines of the Intergovernmental Panel on Climate Change (IPCC). The inventory includes the following sectors: energy| industrial processes| agriculture| forestry and waste. In this paper| only the inventory of the direct greenhouse gases (CO2| CH4 and N2O) is presented. Emissions of these gases were converted to CO2 equivalent emissions by means of their Global Warming Potentials (a measure of the radiative effects of the different gases relatively to CO2). CO2 emissions from burning fossil fuels to produce energy are by far the largest source (50 million tons in 1996). The contribution of methane emissions from decomposition of landfilled municipal solid waste is second in importance (8 million tons of CO2 equivalent). Industrial processes emit about 2 million tons CO2 equivalent| the most important process being cement production. Agricultural emissions amount to about 2 million tons CO2 equivalent and are due to soil emissions of nitrous oxide| methane emissions from enteric fermentation in domestic livestock and N2O and CH4 emissions from animal waste management. Although most forests in Israel are in a growing stage and atmospheric CO2 is therefore removed to form biomass| this removal amounts to 0.4 million tons only and is very small as compared to emissions from other sectors. On a per capita basis| Israel's emissions of CO2 from fuel combustion are not far behind those of some of the most developed countries. 5330,2000,3,4,Investigation of refrigerating system with R12 refrigerant replacements,This paper deals with the influence of R12 working fluid replacements on energy efficiency and global warming expressed by values of Coefficient of Performance (COP) and Total Equivalent Warming Impact (TEWI). Experimental investigations are presented which relate the use of refrigerants R134a| R401A| R409A| R22 and the mixture of R134a with R12 to the values of COP and TEWI of refrigerating system in comparison with R12 application. It is shown that the use of R134a| R401A and R409A refrigerants enables the increase of COP coefficient and significantly reduces the value of TEWI in comparison with R12 application. (C) 1999 Elsevier Science Ltd. All rights reserved. 5234,2000,2,4,Irreversible investment in wetlands preservation: Optimal ecosystem restoration under uncertainty,The question of how to manage a lacustrine wetland is analyzed given the uncertain potential for long-term lake level changes resulting from global warming and the uncertain biological processes involved in creating wetlands. Three management options are considered: do nothing; construct a dike that removes hydrological connections with the lake ("closed dike"); and build a dike that maintains a hydrological connection with the lake| but can be converted to a closed dike under adverse conditions ("open dike"). For all practical purposes| dike construction represents an irreversible choice. The model| a stochastic dynamic program| is used to optimize the timing and type of protective structure under a range of management goals. A wetland can either be optimal for fish or optimal for mammals and waterfowl| but not both. Because credible estimates of the economic values of wetland services do not exist| we treat those values as parameters in a multiobjective analysis and show the decisions implied by alternative valuations. The model is applied to the case of Metzger Marsh| a Lake Erie coastal wetland near Toledo| Ohio| where the decision was made in 1993 to construct an open dike. We find that the optimal decision is robust with respect to varying assumptions about the formation of barrier beaches and the probability of climate change| but that the decision is not robust to assumptions concerning the health of an unprotected Metzger Marsh. The most important source of uncertainty is the biological health of an unprotected wetland. 3140,2000,5,4,Isotopic evidence for late Quaternary climatic change in tropical South America,The tropical hydrologic cycle affects atmospheric trace gases and global climate change| and thus records of hydrologic change encompassing a variety of time scales from the low latitudes are important in paleoclimatology. Isotopic analysis of calcite from Lake Junin| Peru| provides a record of hydrologic variability that spans the last glacial-interglacial transition in the southern tropics. The record reveals a 6 parts per thousand enrichment in delta(18)O(calcite) during the late glacial followed by a gradual depletion during the Holocene| which can be interpreted as a decrease followed by a long-term increase in effective moisture. Close agreement between delta(18)O(calcite) and rainy season insolation indicates that long-term changes in tropical hydrology were linked to orbital variations. Furthermore| hydrologic change was out of phase in the northern and southern tropics over this time period. 5167,2000,2,2,Land and ocean carbon cycle feedback effects on global warming in a simple Earth system model,A simple Earth system model is developed by coupling a box model of the global carbon cycle to an energy-balance approximation of global temperature. The model includes a range of feedback mechanisms between atmospheric CO2| surface temperature and land and ocean carbon cycling. It is used to assess their effect on the global change being driven by anthropogenic CO2 emissions from fossil fuel burning and land-use change. When tuned to reach the 1990 level of atmospheric CO2| the model CO2 predictions for 1832-1990 are reasonably close to ice-core and instrumental records| observed global warming of similar to0.6 K from 1860-1990 is accurately predicted and the land and ocean carbon sinks for the 1980s are close to IPCC central estimates. The ocean sink is reduced by similar to0.3 GtC yr(-1) when the ocean surface is assumed to warm at the same rate as global surface temperature. Land and oceanic carbon sinks are predicted to be growing at present and hence buffering the rate of rise of atmospheric CO2. In the basic model| the current land carbon sink is assumed to be due to CO2 fertilisation of photosynthesis. The slight warming that has occurred enhances soil respiration (carbon loss) and net primary productivity (carbon uptake) by similar amounts. When the model is forced with a "business as usual" (IS92a) emissions scenario for 1990-2100 followed by a linear decline in emissions to zero at 2200| CO2 reaches a peak of 985 ppmv in 2170 and temperature peaks at +5.5 K in 2180. Peak CO2 is similar to 135 ppmv higher than suggested by IPCC for the same forcing| principally because global warming first suppresses the land carbon sink then generates a land carbon source. When warming exceeds similar to4.5 K| soil respiration "overtakes" the CO2 fertilisation of NPP| triggering a release of similar to 70 GtC from terrestrial ecosystems over similar to 100 years. When the effects of temperature on photosynthesis| respiration and soil respiration are removed| peak levels of CO2 are reduced by similar to 100 ppmv and peak temperature by similar to0.5 K. Distinguishing separate soil carbon pools with different residence times does not significantly alter the timing of the switch to a land carbon source or its effect on peak CO2| but it causes the source to persist for longer. If forest re-growth or nitrogen deposition are assumed to contribute to the current land carbon sink| this implies a weaker CO2 fertilisation effect on photosynthesis and generates a larger future carbon source. Peak CO2 levels are also sensitive by about +/- 80 ppmv to upper and lower limits on the temperature responses of photosynthesis| plant respiration and soil respiration. By forcing the model with a range of future emission scenarios it is found that the creation of a significant land carbon source requires rapid warming| exceeding similar to4.5 K| and its magnitude increases with the rate of forcing. The carbon source is greatest for the most rapid burning of the largest reserve of fossil fuel. It is concluded that carbon loss from terrestrial ecosystems may significantly(similar to 10%) amplify global warming under "business as usual" or more extreme scenarios. 3065,2000,5,4,Last Glacial Maximum lacustrine and fluviatile Formations in the Tibesti and other Saharan mountains| and large-scale climatic teleconnections linked to the activity of the Subtropical Jet Stream,In the mountains of the central Sahara (lat ca. 20 degrees to 22 degreesN| long 16 degrees to 19 degreesE) and particularly in the Tibesti mountains| important lacustrine formations developed during the late Pleistocene| primarily during the Last Glacial Maximum (LGM). Two main phases| separated by a brief regression| intervened between ca. 20|000 and 15|500 BP| and between 15|000 and 12|500 BP. Pollen analyses were carried out on four samples of this formation. The high lacustrine levels were associated to both important precipitations and a reduced evaporation linked to lower temperatures. Similar lacustrine deposits were found in the Djebel Marra in the south of the Sahara. In the mountains of the central and eastern Sahara| during the same period and until the middle Holocene| the "Middle Terrace" Formation was deposited in the river valleys of the Tibesti| Hoggar| Air and the Red Sea Hills. Since the southern headwaters of the Nile were dry from ca. 20|000 to 12|500 BP| the fluviatile sediments deposited in the Nile valley in Nubia may have resulted almost entirely from the numerous wadis flowing from the Red Sea Hills. The rainfalls which fed these lacustrine and fluviatile formations were related to the Tropical Depressions which are formed in the southern part of the westerlies and are linked to the activity of the Subtropical Jet Stream (STJ)| whose path remained over the central Sahara from 20|000 BP to the early Holocene. In the Rocky Mountains of the western US| the palaeolakes Lahontan and Bonneville were very large during the LGM and the main fluctuations exhibit similar chronology to that of the Saharan mountains. Broecker [Broecker| W.S.| 1994. Massive iceberg discharges as triggers for global climate change. Nature 372| 421-424] estimates that these two large U.S. wet events between ca. 20|000-15|500 BP and ca. 15|000-12|500 BP may have been an indirect result of two large ice surges in the North Atlantic| related to Heinrich layers 1 and 2. We can assume| however| that the similar climatic variation of the Rocky Mountains and the central and eastern Saharan mountains was also a result of the activity of the STJ all along its path| which marks the boundary between the polar and tropical circulations. STJ activity can apparently produce long-distance climatic teleconnections. During the LGM similar teleconnections also existed in the Southern Hemisphere between South Africa and Australia. The Tropical Depressions result from the interaction of polar troughs and the influx of humid equatorial air forming transversal cloud bands. The large increase in the intensity of atmospheric circulation during the LGM was responsible for a large increase in Tropical Depressions in both hemispheres. (C) 2000 Elsevier Science B.V| All rights reserved. 5340,2000,2,3,Late Quaternary paleogeography and evolution of arctic breeding waders,This review Links published data on mitochondrial DNA phylogeography of three wader species breeding in the Arctic to the availability of suitable breeding habitat during the past 250 000 years. We argue that the breeding ranges of arctic waders were most restricted in size during warm phases in the earth's climate (interglacials)| resulting in population bottlenecks in species breeding in the high arctic zone| such as Red Knot Calidris canutus and Ruddy Turnstone Arenaria interpres| and population contraction and the initiation of genetic divergence in low arctic species| such as Dunlin Calidris alpina. When the climate cooled| all species could spread over larger areas. However| large ice-sheets fragmented tundra habitat| which resulted in more differentiation. Subspecies of Dunlin that became isolated during or before the last glacial period are genetically distinct| while those that originated after the glacial cannot be distinguished using mitochondrial DNA. The sensitivity of waders breeding in the high Arctic to increases in global temperature raises concerns over the effect of possible global warming due to anthropogenic factors on these species. 5230,2000,3,4,Legume green manure as partial fallow replacement in semiarid Saskatchewan: Effect on carbon fluxes,Increasing atmospheric CO2 concentrations| largely due to burning of fossil fuels| may accentuate the risk of global warming. Scientists are optimistic that with appropriate management soils can function as sinks for C and contribute to CO2 abatement strategies. The objective of this study was to determine if soil C can be increased using an annual legume green manure (GM) as partial fallow replacement in a fallow-wheat (Triticum aestivum L.)-wheat (F-W-W) rotation in the Brown soil zone of Saskatchewan. In 1995 and 1996 we measured soil C fluxes in all phases of F-WW and GM-W-W rotations| which were two of the treatments in an experiment initiated in 1987 on a medium-textured Orthic Brown Chernozem. The GM| Indianhead black lentil (Lens culinaris Medikus) was estimated to add 1800 and 1400 kg C ha(-1) in 1995 and 1996| respectively. Annual inputs of C in residues of the wheat crops were two to three times those of GM. Comparison of CO2 emissions from GM with those from the fallow phase of the F-W-W system suggested that GM largely decomposed in the interval between incorporation (mid-July) and freeze-up in fall. Fluxes of CO2 from the wheat phases of GM-W-W closely matched those from the corresponding phases of F-W-W| confirming that there was little carryover of undecomposed GM to the following growing season. Our results suggest that| in a 3-yr rotation| partial fallow replacement with legume GM may have only a minor impact on C sequestration because the increase in C inputs is relatively small (similar to 25% in this study) and GM decomposes rapidly in the soil due to its narrow C:N ratio (12-13). Green manuring may| however| play a more significant role in enhancing soil C levels in a F-W system| where relatively large increases in C inputs could be achieved using currently-available legume species.
5361,2000,3,4,Lessons from utility conservation programs,This paper considers the design| incentives and effectiveness of U.S. demand side management (DSM) programs and tries to explain why this ambitious| almost unanimously embraced initiative failed. Problems on the demand side result from consumers' private information that implies that substantial principal-agent slippage must accompany any conservation incentive the utility offers to the consumer. Moreover| the regulatory incentives induce the American utility to select inefficient programs. Therefore| the utility has little to gain from deterring such strategic reactions and cheating by consumers. As a consequence| the reported conservation exists largely on paper bur not in reality. This ex-post assessment is important for two reasons. First| European countries (Scandinavia| Germany| Austria and others) have been eager to repeat this American regulatory 'success'. Second| the problems addressed in this paper would apply to another round of conservation programs induced by the concern about global warming. 5179,2000,4,3,Li+ ion affinities of global-warming perfluorocarbons,Density functional theory studies were performed for the first time to obtain the Li+ ion affinities of various perfluorocarbons (PFCs) that cause global-warming. Becke's three-parameter hybrid density functional| B3LYP combined with 6-31G(d)| 6-311+G(2d)| and 6-311+G(3df) basis sets were utilized for this purpose. We present optimized geometries of PFC-Li+ ion complexes at B3LYP/6-311+G(2d) level. The frequencies obtained at the same level were used to verify all the optimized geometries are minima. The following PFCs-CF4| CHF3| CH2F2| CH3F| C2F6| C4F8| with SF6-were considered in the present study. The calculated Lif affinities for CF4| CHF3| CH2F2| CH3F| C2F6| C4F8| and SF6 are 12.31| 19.64| 26.84| 30.10| 17.20| 21.09| and 16.92 kcal/mol| respectively at B3LYP/6-311+G(3df) after zero-point energy and thermal energy corrections. The large Li+ affinities indicate the validity of our proposed Li+ ion attachment mass spectrometry to quantify the emission of these greenhouse gases from semiconductor industries. Complex geometries were obtained and the ion-molecular bonding nature was discussed on the basis of atomic charge| electron density rho| and its Laplacian. 5286,2000,3,4,Life cycle assessment and economical evaluation of superconducting magnetic energy storage systems in a power system,In recent years| the introduction of superconducting magnetic energy storage systems (SMES) into a power system is drawing considerable research effort because of their high efficiency rate and large storage capacity characteristics. In this paper| the introduction of SMES into a power system and its effects on energy and on environmental issues are addressed. The analysis results show that the introduction of SMES can considerably cut down CO2 emissions without increasing the production cost if it substitutes for the operation of thermal plants during peak load period. However| to achieve this| nuclear plants are also needed for charging purposes. Thus| an algorithm to find the best generation mix| subject to CO2 emissions constraints and nuclear plant introduction constraints| is proposed. The inclusion of nuclear plant constraints increases the coal consumption| hence CO2 emissions. Nevertheless| in most of the analyzed cases| the introduction of SMES could attain important cost savings and environmental conservation. (C) 2000 Scripta Technica. 5219,2000,3,4,Life cycle assessment of a telecommunications exchange,This paper describes a comparative life cycle assessment (LCA) of a new Business Communication 10 (BC 10) and an old Business Communication 8 (BC 8) model of the private branch exchange Modular Digital 110 (MD 110)| designed and sold by Ericsson Enterprise AB (EE) and produced by Flextronics| in this case for the European Union (EU) market. LCA is a technique for assessing the environmental aspects and potential impact associated with a product's whole life cycle from the "cradle to grave". The study meets the requirements of the standards International Organisation for Standardisation (ISO) 14040:1997 English (E)| ISO 14041:1998 E and the draft standards ISO/Draft International Standard (DIS) 14042 and ISO/DIS 14043 and was critically reviewed by Henrik Wenzel| Instituttet for ProduktUdvikling (The Institute for Product Development| IPU) in Denmark. The modelling of the system includes manufacturing (hardware and EE's organisation)| use stage (electricity consumption)| end-of-life (recycling processes) and transports. Electronic devices axe modelled in depth (16 groups of components) and data from over 40 suppliers have been collected. EE's organisation (development| marketing & sales| supply| installation| service and maintenance) is modelled for the use of offices and business travelling. The following main conclusions of the project are based on results for potential contributions to the environmental impact categories acidification| global warming and eutrophication| which were chosen to be the most relevant. The environmental impact improvements of the new model compared to the old are approximately 10%| and the uncertainty of the results is judged to be smaller than the difference between the systems. The use stage and the manufacturing stage give the largest impacts| both for the new and the old model. In the manufacturing stage| the hardware production clearly dominates. EE's organisation is secondly most important and hardware transport is least important. This is due to more environmental load from service and business travelling in the organisation than environmental load arising from the distribution of the product. The results predominantly reflect energy use| whereas toxicological aspects could not be reliably assessed due to lack of data and reliable methods and needs separate attention. The technology improvements shown for BC 10 compared to BC 8 only describe design improvements made by EE| and do not take into account potential technology production improvements made by component suppliers. 5260,2000,3,3,Life cycle engineering case study: Automobile fender designs,Beginning with the goal and scope definition five different fender designs using steel| aluminum| PP/EPDM| PC/PBT and PPO/PA are described and the boundary conditions set. This exemplary case study demonstrates the general approach and beneficial uses of life cycle assessment and life cycle engineering. The inventory of the fenders shows that the steel design has advantages in terms of lower energy consumption during production. However| when the utilization phase of the fenders is considered| the overall energy consumption of the PP/EPDM fender is smaller due to the slight weight of the this polymer design. Concerning the life cycle impact assessment (LCIA)| the global warming potential of the PP/EPDM design is the smallest of all the fender materials even during the production of the fenders. The inventory analysis shows that the utilization phase of automotive parts is dominated by fuel consumption and related emissions like CO2. Nevertheless the LCIA shows that some impacts are mainly determined in the production phase. For example| the global warming potential of nitrous oxide (N2O) released during PPO/PA material production cannot be compensated for the lower energy demand (and also lower CO2 emissions) during the utilization phase. Economic considerations are also discussed. As a parameter| the cost of parts was chosen. Parts costs depend on material costs| labor costs and other variable costs. In addition| the fixed costs for machines and tools were considered. Steel fenders have the smallest production costs| followed by the PP/EPDM design. Finally| in an overall valuation of the compared fender designs the best design considering primary energy demand| global warming potential| and part costs was investigated. In terms of the specified criteria| the PP/EPDM fender is the best design| however| the results lead to a variety of different conclusions. 5212,2000,3,4,Life-cycle analysis of alternative automobile fuel/propulsion technologies,We examine the economic and environmental implications of the fuels and propulsion technologies that will be available over the next two decades for powering a large proportion of the light duty fleet (cars and light trucks). Since R&D change is rapid| we treat the uncertainty about future technologies using bounding calculations. A lifecycle perspective is used to analyze fossil fuels [conventional unleaded and reformulated gasolines| low sulfur reformulated diesel| and compressed natural gas (CNG)]| ethanol from biomass| and electricity together with current and advanced internal combustion engines (ICE| indirect (port) and direct injection| spark| and compression ignited) and electric vehicles (battery-powered| hybrid electric| and fuel cell). Technological advances continue to improve the efficiency and environmental performance of ICE automobiles powered by low sulfur fossil fuels. Absent a doubling of petroleum prices or stringent regulation [due| for example| to intense concerns about greenhouse gas (GHG) emissions]| ICE using fossil fuels will dominate the market for the next two decades. CNG cars have low emissions| including GHG| but must be redesigned to store enough CNG to achieve the current range. Battery powered cars have limited range and are expensive| and the life-cycle of battery components leads to discharges of toxic materials. Although both hybrid and fuel cell vehicles promise better fuel economy and lower emissions| in the near term these do not justify their higher costs. If global warming becomes a major concern| CNG offers carbon dioxide emission reductions of up to 30%| and bioethanol could provide a fuel with no net carbon dioxide emissions| although the bioethanol price would be more than twice current petroleum prices. 5211,2000,2,4,Low-molecular-weight organoiodine and organobromine compounds released by polar macroalgae - The influence of abiotic factors,The influence of temperature| light| salinity and nutrient availability on the release of volatile halogenated hydrocarbons was investigated in the Antarctic red macroalgal species Gymnogongrus antarcticus Skottsberg. Compared to standard culture condition| an increase in the release rates of iodocompounds was generally found for the exposure of the alga to altered environmental conditions. Macroalgae exhibited higher release rates after adaptation for two months to the changed factors| than after short-term exposure. Monitoring the release rates during a 24 h incubation period (8.25 h light| 15.75 h darkness) showed that changes between light and dark periods had no influence on the release of volatile halocarbons. Compounds like bromoform and 1-iodobutane exhibited constant release rates during the 24 h period. The formation mechanisms and biological role of volatile organohalogens are discussed. Although marine macroalgae are not considered to be the major source of biogenically-produced volatile organohalogens| they contribute significantly to the bromine and iodine cycles in the environment. Under possible environmental changes like global warming and uncontrolled entrophication of the oceans their significance may be increase. 5147,2000,2,4,Magnitude and timing of annual maximum floods: Trends and large-scale climatic associations for the Blacksmith Fork River| Utah,The magnitude and timing of spring snowmelt floods reflects seasonal snow accumulation and spring temperature patterns. Consequently| interannual variations in regions such as the intermountain West| with snowmelt annual maximum floods| may be related to low-frequency variations in winter/spring large-scale climate variability. Changes in the seasonality of basin precipitation and temperature consequent to slow changes in the baseline climate state (e.g.| owing to natural climate variations and/or potential global warming trends) may have significant impacts on such floods. A case study of the Blacksmith Fork River in northern Utah that explores such a hypothesis is presented here. Trends and associations in the magnitude and timing of annual maximum floods are documented| their impact on time-varying estimates of the 100 year flood is assessed| and relationships with known large-scale| quasi-oscillatory patterns of climate variability are explored. Evidence for structured low-frequency variation in flood timing and magnitude and its relation to winter/spring precipitation and temperature and to tropical (EI Nino-Southern Oscillation) and extratropical (Pacific Decadal Oscillation) Pacific climate precursors is presented. Mechanisms for these ocean-atmosphere teleconnections to basin precipitation| temperature| and flood potential are discussed. 5359,2000,5,4,Mammalian responses to Middle Holocene climatic change in the Great Basin of the western United States,In spite of decades of intense research directed toward understanding the climates and ecology of the Great Basin (western United States) during the past 10|000 years| the responses of mammals to the extreme aridity of the Middle Holocene (c. 8000-5000 years ago) in this region have been poorly understood. Using a well-dated small mammal sequence from Homestead Cave| north-central Utah| I show that the Middle Holocene small mammal faunas of this area underwent a decrease in species richness and evenness| driven largely by a series of local extinctions and near-extinctions coupled with a dramatic increase in the abundance of taxa well-adapted to xeric conditions. At the end of this period| some taxa that require relatively mesic habitats began to increase in abundance immediately| others did not rebound in abundance until several thousand years later| while still others have not returned at all. This suite of responses has been difficult to detect because climatic change at the beginning of the Middle Holocene was so much more substantial than that which occurred toward its end. 5252,2000,4,4,Managing uncertainty in climate change projections - Issues for impact assessment - An editorial comment,Climate change projection is the term the IPCC Second Assessment Report (SAR) uses for model estimates of future climate. In that report| projections are presented in two forms: as single model scenarios and as projected ranges of uncertainty. In climate studies| scenarios are commonly regarded as being plausible| but have no further probability attached. Projected ranges of uncertainty can have probabilities attached to the range and within the range| so are more likely to occur than individual scenarios. However| as there is significant remaining uncertainty beyond the projected range| such projections cannot be regarded as forecasts. An appropriate terminology is required to communicate this distinction. The sources of uncertainty in projected ranges of global temperature to 2100 are analysed by Visser et al. (2000)| who recommend that ail major sources of uncertainty be incorporated into global warming projections. This will expand its projected range beyond that of the IPCC SAR. Further sources of uncertainties are contained within projections of regional climate. Several strategies that aim to manage that uncertainty are described. Uncertainty can also be managed where it is unquantifiable. An example is rapid climate change| where discarding the term climate 'surprises' in favour of more precise terminology to aid in identifying possible adaptation strategies| is recommended. 5191,2000,2,4,Mass mortality of marine invertebrates: an unprecedented event in the Northwestern Mediterranean.,An unprecedented mass mortality event has been observed at the end of the summer 1999 along the coasts of Provence (France) and Ligury (Italy). This event has severely affected a wide array of sessile filter-feeder invertebrates from hard-substratum communities| such as sponges (particularly the keratose sponges Hipposongia and Spongia)| cnidarians (particularly the anthozoans Corallium| Paramuricea| Eunicella and Cladocora)| bivalves| ascidians and bryozoans. Along the Provence coasts| the outbreak spread from east to west. Exceptionally high and constant temperatures of the whole water column (23-24 degreesC| for over one month| down to 40 m) could have determined an environmental context favourable to the mass mortality event. Like the thermal anomaly| the mortality is limited in depth. However| rye cannot ascertain whether temperature had a direct effect on organisms or acted in synergy with a latent and/or waterborne agent (microbiological or chemical). Taking into account the global warming context in the NW-Mediterranean| monitoring programs of physical-chemical parameters and vulnerable populations should rapidly be set up. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS. 3148,2000,2,4,Meteorological forcing of plankton dynamics in a large and deep continental European lake,The timing of various plankton successional events in Lake Constance was tightly coupled to a large-scale meteorological phenomenon| the North Atlantic Oscillation (NAO). A causal chain of meteorological| hydrological| and ecological processes connected the NAO as well as winter and early spring meteorological conditions to planktonic events in summer leading to a remarkable memory of climatic effects lasting over almost half a year. The response of Daphnia to meteorological forcing was most probably a direct effect of altered water temperatures on daphnid growth and was not mediated by changes in phytoplankton concentrations. High spring water temperatures during "high-NAO years" enabled high population growth rates| resulting in a high daphnid biomass as early as May. Hence| a critical Daphnia biomass to suppress phytoplankton was reached earlier in high-NAG years yielding an early and longer-lasting clear-water phase. Finally| an earlier summer decline of Daphnia produced in a negative relationship between Daphnia biomass in July and the NAG. Meteorological forcing of the seasonal plankton dynamics in Lake Constance included simple temporal shifts of processes and successional events| but also complex changes in the relative importance of different mechanisms. Since Daphnia plays an important role in plankton succession| a thorough understanding of the regulation of its population dynamics provides the key for predictions of the response of freshwater planktonic food webs to global climate change. 5272,2000,3,4,Methane production by ruminants: its contribution to global warming,The aim of this paper is to review the role of methane in the global warming scenario and to examine the contribution to atmospheric methane made by enteric fermentation| mainly by ruminants. Agricultural emissions of methane in the EU-15 have recently been estimated at 10.2 million tonnes per year and represent the greatest source. Of these| approximately two-thirds come from enteric fermentation and one-third from livestock manure. Fermentation of feeds in the rumen is the largest source of methane from enteric fermentation and this paper considers in detail the reasons for| and the consequences of| the fact that the molar percentage of the different volatile fatty acids produced during fermentation influences the production of methane in the rumen. Acetate and butyrate promote methane production while propionate formation can be considered as a competitive pathway for hydrogen use in the rumen. The many alternative approaches to reducing methane are considered| both in terms of reduction per animal and reduction per unit of animal product. It was concluded that the most promising areas for future research for reducing methanogenesis are the development of new products/delivery systems for anti-methanogenic compounds or alternative electron accepters in the rumen and reduction in protozoal numbers in the rumen. It is also stressed that the reason ruminants are so important to mankind is that much of the world's biomass is rich in fibre. They can convert this into high quality protein sources (i.e. meat and milk) for human consumption and this will need to be balanced against the concomitant production of methane. 5165,2000,4,4,Methane transport capacity of rice plants. I. Influence of methane concentration and growth stage analyzed with an automated measuring system,A major portion (60-90%) of the methane (CH4) emitted from rice fields to the atmosphere is transported through the aerenchyma of the rice plants. However| a rapid and accurate method to study the CH4 transport capacity (MTC) of rice plants is not available. We developed a gas sampling and analytical device based on a closed two-compartment chamber technique and analyzed the enrichment of the CH4 mixing ratio inside the shoot compartment of cylindrical cuvettes enclosing individual rice plants under ambient conditions. The computer-controlled analytical system consists of a gas chromatograph (GC) and a pressure-controlled autosampler for eight cuvettes (seven for plants and one for CH4-calibration gas). The system automates closure and opening of plant cuvettes using pneumatic pressure| air sample collection and injection into the GC| and CH4 analysis. It minimizes sources of error during air sampling by continuously mixing headspace air of each cuvette| maintaining pressure and composition of the headspace inside the cuvettes| purging the dead volumes between the sampler induction tube and GC| and running a reference CH4-calibration gas sample in each cycle. Tests showed that the automated system is a useful tool for accurate sampling of headspace air of cylindrical cuvettes enclosing individual rice plants and enables rapid and accurate fully automated analysis of CH4 in the headspace air samples. A linear relationship was obtained between CH4 transported by rice plants of two cultivars (IR72| a high-yielding dwarf| and Dular| a traditional tall cultivar) and concentration of CH4 up to 7|500 ppm used for purging the nutrient culture solution surrounding the roots in the root compartment of the chamber. Further increase in CH4 emission by shoots was not observed at 10|000 ppm CH4 concentration in the root compartment of the chamber. The MTC of IR72 was measured at six development stages; it was lowest at seedling stage| increasing gradually until panicle initiation. There was no further change at flowering| but a marked decrease at maturity was noted. These results suggest that the plants have 45-246% greater potential to transport CH4 than the highest CH4 emission rates reported under field conditions| and plants would not emit CH4 at early growth and at a reduced rate close to ripening. 5166,2000,3,4,Methane transport capacity of rice plants. II. Variations among different rice cultivars and relationship with morphological characteristics,Of the total methane (CH4) emitted from a rice field during the growing season 60-90% is emitted through the rice plants. We determined the methane transport capacity (MTC) of rice plants at different physiological growth stages using an automatic measuring system under greenhouse conditions. A total of 12 cultivars (10 inbred varieties and 2 hybrids) were studied in sets of two experiments and was distinguished into three groups according to the patterns of MTC development. MTC is generally increasing from seedling stage to panicle initiation (PI)| but differs in the development from PI to maturity. While the hybrid showed a gradual increase in MTC| the inbred cultivars showed either minor changes in MTC or a drastic decrease from flowering to maturity. Among tall cultivars| Dular showed the highest MTC| followed by B40; the lowest MTC was found in Intan. High-yielding dwarf cultivars showed MTC in the descending order of IR72 > IR52 > IR64 > PSBRc 20. New plant type cultivars showed very low MTC with IR65600 exhibiting the smallest MTC at PI| flowering| and maturity. Hybrids (Magat and APHR 2) showed the largest MTC that continued to increased with plant growth. The MTC patterns were attributed to growth parameters and the development of morphological characteristics of the aerenchyma. These results suggest that in tall| dwarf| and NPT cultivars| increase in root or aboveground biomass during initial growth determines a corresponding increase in MTC. Once aerenchyma has fully developed| further increase in plant biomass would not influence MTC. However| in the case of hybrids| a positive relationship of MTC with root + shoot biomass (r = 0.672| p greater than or equal to 0.05) and a total plant biomass including grain (r = 0.849| p greater than or equal to 0.01) indicate continuous development of aerenchyma with plant growth| resulting in enhanced MTC. In all cultivars| tiller number| but not height| was linearly related to MTC| indicating that the number of outlets/channels rather than plant size/biomass determines the transport of CH4. These results clearly demonstrate that rice cultivars differ significantly in MTC. Therefore| the use of high-yielding cultivars with low MTC (for example| PSBRc 20| IR65598| and IR65600) could be an economically feasible| environmentally sound| and promising approach to mitigate CH4 emissions from rice fields. 5214,2000,5,4,Microfloral diversity patterns of the late Paleocene-Eocene interval in Colombia| northern South America,The late Paleocene-early Eocene interval was characterized by a long period of global warming that culminated with the highest temperatures of the Tertiary. This interval was also associated with plant extinctions and a subsequent increase in plant diversity in temperate latitudes. However| tropical regions remain largely unknown. We compare the microfloral diversity of the late Paleocene with the fate early to middle Eocene in flood plain| coastal plain| and estuarine facies of a section in the Colombian eastern Andes. Several techniques such as range-through method| rarefaction| bootstrap| detrended correspondence analysis| and Simpson index were used to assess the significance of the diversity pattern observed throughout the section. The microfloral record indicates a distinct| diverse Paleocene flora declining toward the end of the Paleocene| being replaced by a different and much more diverse Eocene flora. It is uncertain| however| how these floral changes correlate with the latest Paleocene thermal maximum and Eocene thermal maximum events. 3146,2000,5,4,Middle- and late-Wisconsin paleobotanic and paleoclimatic records from the southern Colorado Plateau| USA,The Colorado Plateau is a distinct physiographic province in western North America| which presently straddles the transition between summer-wet and summer-dry climatic regimes to the south and northwest| respectively. In addition to climate| the diversity of environments and plant communities on the Colorado Plateau has resulted from extreme topographic diversity. Desert lowlands as low as 360 m elevation are surrounded by forested plateaus| and even higher peaks greater than 3800 m elevation. This environmental diversity provides a unique opportunity to study the history of biotic communities in an arid region of North America. Although the Colorado Plateau harbours numerous potential sites| the paleoecological record of the Plateau is poorly known. Potential deposits for analysis include packrat middens| alluvial and cave sites at lower elevations| and lake| bog and wetland sites at higher elevations. Forty-six sites have been analysed across the nearly 337|000 km(2) region| of which 27 contain records that span Marine Oxygen Isotope Stage (IS) 2 data| with IS 3 information coming from only 12 sites. Most IS 2 and 3 sites are clustered along the lowland regions of the Colorado River corridor and the uplands of the Mogollon Rim area. We compiled selected data from long paleoecological records to examine patterns of vegetation and climate change across the southern Colorado Plateau for the middle and late Wisconsin. During the middle Wisconsin| mixed conifers covered middle-elevations presently dominated by ponderosa pine (Pinus ponderosa)| and juniper (Juniperus) woodland grew at elevations today covered by blackbrush (Coleogyne) and sagebrush (Artemisia) desert. During the late Wisconsin| boreal conifers| primarily Engelmann spruce (Picea engelmannii)| replaced the mixed conifer association. Estimates of mean annual temperatures (MAT) during IS 3 were at least 3-4 degrees C cooler than today| whereas IS 2 MAT estimates are at least 5 degrees C colder. Our investigation of millennial-scale climatic variability within the region provided equivocal results. The packrat midden sequence could not distinguish vegetation changes that might be associated with Heinrich events in the North Atlantic. From the lake records| however| many Heinrich events were associated with generally drier intervals| often with elevated sagebrush pollen concentrations. Future paleoecological investigations should concentrate on the northern Colorado Plateau| as well as the eastern and western margins. Additional sites| along with closer-spaced sampling in regions already studied| will be important in determining the history of important climatic phenomena such as the timings of the Arizona monsoon. (C) 2000 Elsevier Science B.V. All rights reserved. 5240,2000,5,3,Millennial-scale rhythms in peatlands in the western interior of Canada and in the global carbon cycle,A(1) natural similar to 1450-yr global Holocene climate periodicity underlies a portion of the present global warming trend. Calibrated basal radiocarbon dates from 71 paludified peatlands across the western interior of Canada demonstrate that this periodicity regulated western Canadian peatland initiation. Peatlands| the largest terrestrial carbon pool| and their carbon-budgets are sensitive to hydrological fluctuations. The global atmospheric carbon-budget experienced corresponding fluctuations| as recorded in the Holocene atmospheric CO2 record from Taylor Dome| Antarctica. While the climate changes following this similar to 1450-yr periodicity were sufficient to affect the global carbon-budget| the resultant atmospheric CO2 fluctuations did not cause a runaway climate-CO2 feedback loop| This demonstrates that global carbon-budgets are sensitive to small climatic fluctuations; thus international agreements on greenhouse gasses need to take into account the natural carbon-budget imbalance of regions with large climatically sensitive carbon pools. (C) 2000 University of Washington. 3122,2000,4,4,Modeling terrestrial hydrological systems at the continental scale: Testing the accuracy of an atmospheric GCM,A global hydrological routing algorithm (HYDRA) that simulates seasonal river discharge and changes in surface water level on a spatial resolution of 5' long x 5' lat is presented. The model is based an previous work by M. T. Coe and incorporates major improvements from that work including 1) the ability to simulate monthly and seasonal variations in discharge and lake and wetland level| and 2) direct representation of man-made dams and reservoirs. HYDRA requires as input daily or monthly mean averages of runoff| precipitation| and evaporation either from GCM output or observations. As an example of the utility of HYDRA in evaluating GCM simulations| the model is forced with monthly mean estimates of runoff from the National Centers for Environmental Prediction (NCEP) reanalysis dataset. The simulated river discharge clearly shows that although the NCEP runoff captures the large-scale features of the observed terrestrial hydrology| there are numerous differences in detail from observations. The simulated mean annual discharge is within +/-20% at only 13 of 90 fluvial gauging stations compared. In general| the discharge is overestimated for most of the northern high latitudes| midcontinental North America| eastern Europe. central and eastern Asia| India| and northern Africa. Only in western Europe and eastern North America is the discharge consistently underestimated. Although there appears to be a need for improved simulation of land surface physics in the NCEP product and parameterization of how velocities within HYDRA| the timing of the monthly mean discharge is in fair agreement with the observations. Including lakes within HYDRA reduces the amplitude of the seasonal cycle of discharge and the magnitude of the annual mean discharge of the St. Lawrence River system| in qualitative agreement with the observations. In addition| including the wetlands of the Sudd reduces the magnitude of the simulated annual discharge of the Nile River to values in better agreement with observations. Finally| the impact of man-made dams and their reservoirs on the magnitude of monthly mean discharge can be explicitly included within HYDRA. As an example| including darns and reservoirs on the Parana River improves the agreement of the simulated mean monthly discharge with observations by reducing the amplitude of the seasonal cycle to values in good agreement with the observations. The results of this study show that| although improvements can be obtained through better representations of flow velocities and more accurate digital elevation models. HYDRA can be a powerful tool for diagnosing simulated terrestrial hydrology and investigations of global climate change. 3064,2000,2,3,Modelling the vegetation of China using the process-based equilibrium terrestrial biosphere model BIOME3,1 We model the potential vegetation and annual net primary production (NPP) of China on a 10' grid under the present climate using the processed-based equilibrium terrestrial biosphere model BIOME3. The simulated distribution of the vegetation was in general in good agreement with the potential natural vegetation based on a numerical comparison between the two maps using the DeltaV statistic (DeltaV = 0.23). Predicted and measured NPP were also similar| especially in terms of biome-averages. 2 A coupled ocean-atmosphere general circulation model including sulphate aerosols was used to drive a double greenhouse gas scenario for 2070-2099. Simulated vegetation maps from two different CO2 scenarios (340 and 500 p.p.m.v.) were compared to the baseline biome map using DeltaV. Climate change alone produced a large reduction in desert| alpine tundra and ice/polar desert| and a general pole-ward shift of the boreal| temperate deciduous| warm-temperate evergreen and tropical forest belts| a decline in boreal deciduous forest and the appearance of tropical deciduous forest. The inclusion of CO2 physiological effects led to a marked decrease in moist savannas and desert| a general decrease for grasslands and steppe| and disappearance of xeric woodland/scrub. Temperate deciduous broadleaved forest| however| shifted north to occupy nearly half the area of previously temperate mixed forest. 3 The impact of climate change and increasing CO2 is not only on biogeography| but also on potential NPP. The NPP values for most of the biomes in the scenarios with CO2 set at 340 p.p.m.v. and 500 p.p.m.v. are greater than those under the current climate| except for the temperate deciduous forest| temperate evergreen broadleaved forest| tropical rain forest| tropical seasonal forest| and xeric woodland/scrub biomes. Total vegetation and total carbon is simulated to increase significantly in the future climate scenario| both with and without the CO2 direct physiological effect. 4 Our results show that the global process-based equilibrium terrestrial biosphere model BIOME3 can be used successfully at a regional scale. 5251,2000,3,3,Multiphase CO2 flow| transport and sequestration in the Powder River Basin| Wyoming| USA,Sequestration of anthropogenic "greenhouse gases" such as CO2 is proposed as a means of reducing global warming. We tested the possibility of sequestering CO2 in regional-scale aquifers in sedimentary basins| including residence time in possible aquifer storage sites and migration rates away from such sites. The example basin studied is the Powder River Basin| Wyoming. We calibrated regional scale rock properties in the Powder River Basin using surface heat flow observations. We determined advection by a regional-scale groundwater flow system in the basin can explain anomalously high surface heat flow not explained by conduction alone. Our study suggests that regional scale sedimentary basin aquifers are viable candidates for CO2 sequestration for time-scales of 10(3) years. (C) 2000 Elsevier Science B.V. All rights reserved. 5148,2000,4,4,Natural gas and gas hydrate accumulations within permafrost in Russia,Sudden natural gas blowouts from within the permafrost sections in West and East Siberia and some results of permafrost core samples study are presented. Topics covered include gas geochemistry| blowout intensity (gas flow rate)| depth interval and permafrost rock peculiarities in places of these gas releases. Although microbial gas is widespread within permafrost| thermogenic gas can also occasionally migrate from deep gas reservoirs along faults| or be present locally in areas of gas reservoirs within the permafrost section. Gas can be preserved within permafrost in a free state as well as in hydrate form throughout the permafrost zone and be a potential threat to climate in the course of global warming. (C) 2000 Elsevier Science B.V. All rights reserved. 3151,2000,2,4,Need and opportunity for a North American caribou knowledge cooperative,The importance of migratory caribou (Rangifer tarandus) to northerners| the increasing pressure to extract non-living resources| and predicted global climate change have led researchers| managers and resource users alike to focus on how to improve our knowledge of this unique northern ungulate. Unprecedented threats to caribou sustainability| along with the increasingly acknowledged value of indigenous hunters' contribution to caribou research| pose the additional challenge to innovate research methods that accommodate differing cultural perspectives and facilitate communication among groups. This paper surveys the state of scientific knowledge of the eleven major northern mainland herds of North America. We recommend an approach to improve our working knowledge of barren-ground caribou in order to assess better future impacts. The transfer of knowledge gained from years of research and indigenous experience on many aspects of caribou ecology should be evaluated and| where applicable| transferred to herds with more modest databases. The establishment of a North American Caribou Monitoring and Assessment System| based on a synthesis of local knowledge and research-based science| is recommended as a tool for improved communication and collective learning. 5317,2000,3,2,Neoclasic economic theory and environmental policy instruments,Climate changes| due to global warming by anthropogenic emissions of greenhouse gases in a higher rate than their natural remotion from the atmosphere| ask for adopting effective policies to mitigate those emissions. An important aspect about the future of such policies must be increasing the mitigation action cost effectiveness. In these lines| the object of this article is to identify environment policy instruments applied in the international level| which may grant a reference to improve local environmental policies in developing countries. Advantages and disadvantages of applying those instruments in some countries are analyzed and some mechanisms and instruments applicable in those realities are discussed. 5305,2000,2,4,Nest-site selection in two eublepharid gecko species with temperature-dependent sex determination and one with genotypic sex determination,At present| most turtles| all crocodilians| and several lizards are known to have temperature-dependent sex determination (TSD). Due to the dependence of sex determination on incubation temperature| the long-term survival of TSD species may be jeopardized by global climate changes. The current study was designed to assess the degree to which this concern is justified by examining nest-site selection in two species of Pattern II TSD geckos (Eublepharis macularius and Hemitheconyx caudicinctus) and comparing these preferences with those of a species with genotypic sex determination (GSD) (Coleonyx mitratus). Temperature preferences for nest sites were found to be both species-specific and female-specific. While H. caudicinctus females selected a mean nest-site temperature (32.4 degrees) very close to the upper pivotal temperature (32 degrees C) for the species| E. macularius females selected a mean nest-site temperature (28.7 degrees C) well below this species' lower pivotal temperature (30.5 degrees C). Thus| the resultant sex ratios are expected to differ between these two TSD species. Additionally| nest-site temperatures for the GSD species were significantly more variable (SE = +/-0.37) than were temperatures for either of the TSD species (E. macularius SE = +/- 0.10; H. caudicinctus SE = +/-0.17)| thereby further demonstrating temperature preferences within the TSD species. (C) 2000 The Linnean Society of London. 5255,2000,3,4,New "green" heat transfer fluids,A new segregated hydrofluoroether under development has a global warming potential <3% that of comparable perfluorocarbon fluids. With a boiling point of 128 degrees C| this fluid is well suited for use in ion implanters| steppers| etchers| plasma-aided tools| and automated testers. Its heat transfer performance is shown to be superior to that of perfluorinated fluids of similar boiling point. Electrical properties permit its use in all but the most demanding dielectric applications. Material compatibility should permit "drop-in" substitution in well-designed PFC systems. 5193,2000,5,4,New chronology for the late Paleocene thermal maximum and its environmental implications,The late Paleocene thermal maximum (LPTM) is associated with a brief| but intense| interval of global warming and a massive perturbation of the global carbon cycle. We hare developed a new orbital chronology for Ocean Drilling Program (ODP) Site 690 (Weddell Sea| Southern Ocean) by using spectral analysis of high-resolution geochemical records. The LPTM interval spans 11 precessional cycles yielding a duration of 210 to 220 k.y. The delta(13)C anomaly associated with the LPTM has a magnitude of about -2.5 parts per thousand to -3 parts per thousand; we show that about -2 parts per thousand of the excursion occurs within two steps that each were less than 1000 yr in duration| The remainder developed through a series of steps over similar to 52 k.y. The timing of these steps is consistent with a series of nearly catastrophic releases of methane from gas hydrates| punctuated by intervals of relative equilibria between hydrate dissociation and carbon burial. Further| we are able to correlate the records between ODP Sites 690 and 1051 (western North Atlantic) on the scale of 21 k.y. cycles| which demonstrates that the details of the delta(13)C excursion are recognizable between distant sites. Comparison of cycle records at Sites 690 and 1051 suggests that sediment representing the interval similar to 30 k.y. just prior to and at the onset of the LPTM are missing in the latter location. This unconformity probably resulted from slope failure accompanying methane hydrate dissociation within 10 k.y. of the start of the LPTM. 5221,2000,2,4,Nitrogen in Russian bogs,The nitrogen pool in Russian peatlands reaches 4.69 x 10(9) t. Half of this amount is stored in humic substances (mainly| in humic acids) of peat. The nitrogen of relatively stable compounds (mainly| the humin nitrogen) constitutes about 1.8 x 10(9) t. Easily hydrolyzable and mineral nitrogen compounds constitute 9.7 and 1.8% of the total nitrogen pool| respectively. Most of the nitrogen in eutrophic bogs is bound with humic substances| while that of oligotrophic peat is represented by poorly hydrolyzable and nonhydrolyzable forms. The pool of water-soluble nitrogen constitutes 20.3 x 10(6) t| or 0.43% of the total nitrogen reserve. In the case of global warming| eutrophic and mesotrophic bogs can become an important source of ammonia emission to the atmosphere. 5284,2000,2,4,Nitrogen transformations in a forested catchment in southern Norway subjected to elevated temperature and CO2,Model predictions on the response of soil processes to global warming are mostly inferred from small-scale laboratory studies. In this study| a forested catchment in southern Norway was enclosed by a greenhouse and experimentally manipulated by increasing CO2 (+200 mu l l(-1) above ambient) and temperature (+3-5 degrees C). This paper reports on the effects of the climate manipulation on N mineralization and nitrification. We measured net N mineralization and nitrification in a control and treated part of the greenhouse as well as in an uncovered reference catchment in plots dominated by Calluna vulgaris (L.) Hull or Vaccinium myrtillus L. Net N mineralization in the 0-10 cm soil layer significantly increased| most likely as a result of increased temperature. The effect was largest in plots dominated by Calluna. Nitrification did not significantly increase. Soil moisture inside the incubated cores was not affected by the climate change treatment. Pre-treatment mineralization was similar inside and outside the enclosure whereas nitrification was higher inside the enclosure. The NH4+ content was significantly lower inside the chamber due to removal of acidifying components from the precipitation and lower inputs of dry deposition. We found however no differences in pH| %C and %N of the LF and H layer and total C and N in the soil cores between the two catchments. Mineralization was generally higher under Vaccinium than under Calluna even though measured soil chemical and physical characteristics were similar. Nitrification was higher under Calluna than under Vaccinium. (C) 2000 Elsevier Science B.V. All rights reserved. 5271,2000,3,4,Nitrous oxide emissions from fertilized upland fields in Thailand,Nitrous oxide (N2O) emission from fertilized maize fields was measured using a closed chamber at four experimental sites in Thailand. The average measured N2O flux from unfertilized plots through crop season was 4.16 +/- 1.52| 5.05 +/- 1.65| 5.25 +/- 1.68 and 6.74 +/- 2.95 mu g N2O-N m(-2) h(-1)| at Nakhon Sawan| Phra Phutthabat| Khon Kaen and Chiang Mai| respectively. Increased N2O emissions by the application of nitrogen fertilizer were 0.22-0.44| 0.19-0.38%| 0.12-0.24 and 0.08-0.15% of the applied N| respectively. Compared to other data| N2O emission rate to applied nitrogen was not significantly different between the data of Thailand and the Temperate Zone. 3120,2000,4,4,NLOSS: A mechanistic model of denitrified N2O and N-2 evolution from soil,Soil microbial denitrification is a significant source of atmospheric nitrous oxide (N2O)| a trace gas important in global climate change and stratospheric ozone depletion. In this paper we describe a mechanistic submodel| which is incorporated in the model NLOSS| designed to predict the soil biogenic source and efflux of N2O and N-2 during denitrification| NLOSS simulates transient soil moisture and temperature| decomposition| soil anaerobicity| denitrifying bacterial biomass| rates of soil nitrogen transformations| soil trace-gas transport| and gas efflux to the atmosphere. Uncertainty in predicted N gas effluxes is commuted using a Monte Carlo approach. We test NLOSS's denitrification estimates by comparing predictions with results from a N-15 tracer experiment in a Mexican agricultural system. The model accurately predicted the measured soil moisture and denitrified N2O and N-2 fluxes during the experiment. We also apply NLOSS to compute denitrified N trace-gas speciation curves as a function of soil hydrologic properties and moisture content. These speciation curves will be used in future work to extrapolate the plot-scale modeling results presented here to field and regional estimates of N trace-gas emissions. The results presented here suggest that NLOSS can be used to identify the processes most important for trace-gas losses and to facilitate efforts to scale plot-level modeling results to regional estimates of N trace-gas emissions. 5351,2000,5,4,Numerical modelling of the ice sheet in western Dronning Maud Land| East Antarctica: impacts of present| past and future climates,Time-dependent ice-sheer modelling of a 170 000 km(2) area in western Dronning; Maud Land| Last Antarctica| provided information on the ice sheet's response to sis climate-change scenarios. Another experiment was done to study changes in ice thickness. flow and basal temperature conditions between the present ice configuration and a simulated maximum palaeo-ice sheet. The input to the model included new datasets of bed and surface topography compiled for this study The results of the six climate-change experiments| including a 0.5 degrees C per century global-warming scenario| show that the ice sheet has a robust behaviour with respect to the different climate changes. The maximum change in ice volume was <5% of the initial volume in all climate runs. This is for only relatively short-term climate changes without major changes in global sea level| and also a simulated ice sheet without an ice shelf. The modelled long-term response time of the ice sheet 20 kyr or more. indicates that the ice sheet may still be adjusting tl| the climate change that ended the Last Glacial Maximum. In the maximum palaeo-ice-sheet simulation. with a 5 degrees C climate cooling and the: grounding line located at the continental-shelf margin| ice thickness increased drastically downstream from the Heimefrontfjella mountain range bur remained basically unaffected on the upstream polar plateau. Compared to present conditions| complex changes in basal temperatures were observed. The extent of areas with basal melting increased| for example in the deep trough of the Vest-straumen ice stream. Areas at intermediate elevations in the landscape also experienced increased basal temperatures. with significant areas reaching; the melting point. In contrast high-altitude areas that today are clearly cold-based| such as around Heimefrontfjella and Vestfjella and the Hogisen dome| experienced a 5 10 degrees C decrease in basal temperatures in the palaeo-ice-sheet reconstruction. The results suggest that the alpine landscape within these mountain regions was formed by wet-based local glaciers and ice sheets prior to the late Cenozoic. 5245,2000,3,3,Numerical simulation of infiltration in soil of Australian arid land,It is considered that large-scale afforestation in arid and semi-arid land is one of the most promising countermeasures for fixation of carbon dioxide| which is mainly responsible for the global warming problem. Afforestation of arid land is hindered by water shortages| and requires more effective utilization of limited rainwater. The concept of this study is to evaluate the various countermeasures for constructing water balance system| from different viewpoints of conventional element-technology-oriented measures. In this study| Leonora in Western Australia was selected as a research area| and the infiltration process in the area was analyzed by two kinds of simulation models. Their validity was tested by comparing with the experimental results using glass beads with simple characteristics. It was clearly demonstrated that each model has its own problems. Then we evaluated the infiltration rate of precipitated water into Australian specific soil by the model which showed better approximation results to the experiments with glass beads. As a result| it is suggested that the poor permeability of the soil limits plant growth in the Australian specific area. 5383,2000,4,4,Oceanic hydrates: More questions than answers,From an oil industry standpoint| methane hydrate is known as a major problem because it plugs casing and pipelines. From a media standpoint| hydrates provide an almost inexhaustible supply of articles concerning greenhouse effects| landslides| global warming and mysterious events such as the loss of aircraft in the "Bermuda Triangle". From a scientific standpoint| they provide much scope for academic research projects. Oceanic hydrates have been recovered in some of the thousands of ODP/Joides boreholes| from which a total of over 250 km of core have been taken. Unfortunately| hydrates dissociate when brought on deck| and few samples were preserved for further analysis. Most of the oceanic hydrates are reported to be of biogenic origin| except where they overlie petroleum reservoirs| as in the Caspian Sea and Gulf of Mexico. The hydrates in the cores are found mostly as dispersed grains or thin laminae. Massive pieces of hydrate| greater than 10cm thick| have been found only at three sites. Downhole logs are unreliable indicates of hydrates due to cave-ins| and in many instances the inferred presence of hydrates depends on indirect evidence| such as seismic reflectors (BSR) or chlorinity changes in pore waters. The oil industry requires much better evidence than this before attributing reserve status to a resource| yet in the case of hydrates| enormous deposits (such as recently declared in New Caledonia) are reported on the strength of no more than uncertain seismic information. The gas hydrate stability zone (GHSZ) occurs in oceanic sediments over the first few hundred meters below the seabed. In this zone| any methane from organic material| including any seepages from below| is converted into solid hydrate| and is locked in place in the sediments. The origin of the methane is poorly understood| with even its biogenic origin being challenged. Dissolved methane or free gas may precipitate at geological discontinuities such a faults| fractures and lithological boundaries| as well as at water salinity| temperature and pressure interfaces. In the past| the porosity in the GHSZ was thought to be dominantly filled by hydrate| thus providing a seal to gas| at and below the base of the stability zone. However| at the Blake Ridge| ODP Leg 164 found only minor porosity (maximum of about 5%) being filled by hydrate or gas. The recent Leg 172 in the same area failed to find any hydrate at all. A much higher concentration has been indicated in the Japan National Oil Company hydrate borehole in the Nankai Trough| although this is contradicted by other reports. The Bottom Simulating Reflector (BSR) seismic reflector is caused mainly by gas bubbles at the base of the stability zone| which accordingly cannot act as a seal because the porosity is more than 95% filled by water| with the size of the pores and the gas bubbles being further factors. This is one reason why the BSR reflector does not correspond with the hydrate zones| as had been assumed. Cascadia| off Oregon| is one of the best places to investigate hydrates| as they crop out on the seafloor whereas on the Blake Ridge the first 200 m lack hydrates. Prior to 1998| the resources of hydrates were often declared to be much greater than all known fossil fuels (coal| oil and natural gas). Ginsburg (1998) disputed such claims on the grounds that the hydrates are not continuously distributed vertically or horizontally. Mole recently| the USGS (Course 14| AAPG 2000) has drastically reduced its past estimates to a level where it is now claimed that hydrate accumulations may only rival the known reserves of conventional gas. These dispersed hydrate deposits may be better compared with dispersed oil and gas in petroleum systems| which are very much larger than the amounts contained in commercial reservoirs. Many graphs on solubility of methane in water are computed from formulae| being rarely checked by experiments. Measurements in the laboratory seem to differ from field measurements in sediments. The solubility of methane in deep water is but poorly known| as few measurements have been taken| bur it seems to be about a hundred rimes higher than in near surface-water. Methane released in deep ware| is dissolved in water| even when a large amount of methane is released. It cannot accordingly be the cause of any hazards. But little is known about the fate of the deep dissolved methane in upwelling seawater currents. Methane hydrates are less dense than water when on the seafloor down to a certain depth| which is still unknown (2650 m for CO2 hydrate). So| extrusions of hydrate tend to float upwards| disappearing into the seawater. Log measurements in sediments report hydrates being denser than water| but direct measurements are lacking| and it would seem that such sediments are also subject to buoyancy pressure. Surficial pockmarks and mud volcanoes arise from gas expelled from overpressured| underconsolidated sediments - with or without hydrates being present. Progress in understanding oceanic hydrates has not advanced much over the last twenty years because of the poor quality of measurements in soft sediments (cores| samples and logs) and because of the lack of calibration of seismic against a known oceanic hydrate system. The chance of a viable production method being developed is slim because the oceanic hydrates are dispersed and occur in erratic patches. Only national oil companies in Japan and India are actively exploring for them. Future progress may come from the deepwater exploration being undertaken by the oil industry using better tools| but oceanic hydrates seem to be similar in some respects to metallic nodules or gold in seawater-too dispersed to ever prove economic in most places. It is well said that they are a fuel for the future and likely to remain so. 3094,2000,4,4,On the widespread winter fog in Northeastern Pakistan and India,During the last two winters widespread fog frequently occurred in northeastern India and Pakistan| in a region extending over 1500 km. A particularly severe fog episode lasted from midDecember| 1998 to early January| 1999. The fog caused extensive economic damage and disruptions in transport. We determined concentrations of SO42-| NO3-| and selected trace elements at Lahore| Pakistan during and after the fog event by collecting aerosols on Whatman 41 filters every 12 h. SO42- concentrations of up to 100 mu g/m(3) were observed during fog. The SO42-/Se ratios and trace element data suggest a distant source of SO42- aerosols| hundreds of kms away. Lahore was downwind of coal-burning in India during the fog. The high concentrations of SO42- observed suggest a more extensive investigation of the chemistry and transport processes in this region is necessary to delineate emission sources and develop control strategies as there are serious likely effects on human health and economy in a region populated by hundreds of millions of people| and on global climate change through direct;md indirect forcing. 3134,2000,2,4,Organic matter accumulation| peat chemistry| and permafrost melting in peatlands of boreal Alberta,In the discontinuous permafrost zone of boreal western continental Canada| permafrost is limited almost exclusively to ombrotrophic peatlands. Permafrost in peatlands recently has been degrading and continues to degrade at its southern limit across western Canada| with no evidence of regeneration. The melting of permafrost could have dramatic effects on organic matter accumulation| organochemical properties| and nutrient status in peatlands. Our objectives are to quantify differences in peat chemistry (i.e.| concentrations of organic fractions| N| P| and S) and rates of organic matter accumulation over the past 200 years between a site with permafrost| a site with degraded permafrost (internal lawn)| and three sites with no evidence of permafrost since the last glaciation (continental peatlands: two bogs and one poor Fen). Results indicate that pear chemistry may differ according to the presence| absence| or degradation of permafrost. Recent rates of organic matter accumulation follow similar trends over the past 100-200 years in the permafrost and continental bogs; however| net rates of organic matter accumulation are accelerated by 60% in the internal lawn. As decomposition in peatlands is influenced by nutrient limitations and organic matter quality| peat chemistry is likely to be a critical factor in the carbon balance response of boreal peatlands to climate change. 5175,2000,5,4,Paleoecology and its application to fire and vegetation management in Kootenay National Park| British Columbia,High-resolution analysis of macroscopic charcoal and pollen ratios were used to reconstruct a 10|000 yr history of fire and vegetation change around Dog Lake| now in the Montane Spruce biogeoclimatic zone of southeastern British Columbia. Lake sediment charcoal records suggest that fire was more frequent in the early Holocene from 10|000 to 8200 calendar yrs BP| when climate was warmer and drier than today and forest fuels were limited. Fire frequency increased and reached its maximum during the early to mid-Holocene from 8200 to 4000 calendar yrs BP| corresponding to the dry and warm Hypsithermal period in the Rocky Mountains. During the Hypsithermal period forests around Dog Lake were dominated by Pseudotsuga/Larix|Pinus and open meadows of Poaceae that were subject to frequent fire. From 4000 calendar yrs BP to present| fires became less frequent with the onset of cooler and wetter Neoglacial climate and an increase in wet-closed Picea and Abies forests in the valley. Changes in fire frequency are supported by dry-open/wet-closed pollen ratio data indicating that forest type and disturbance regimes vary with changing climate. The fire frequency and forest cover reconstructions from Dog Lake are a first attempt at defining a range of natural variability for Montane Spruce forests in southeastern British Columbia. Fire and vegetation management in Kootenay National Park can now use this century to millennial-scale range of variability to define the context of current forest conditions and potential changes under global warming scenarios. 5194,2000,4,3,Parallel climate model (PCM) control and transient simulations,The Department of Energy (DOE) supported Parallel Climate Model (PCM) makes use of the NCAR Community Climate Model (CCM3) and Land Surface Model (LSM) for the atmospheric and land surface components| respectively| the DOE Los Alamos National Laboratory Parallel Ocean Program (POP) for the ocean component| and the Naval Postgraduate School sea-ice model. The PCM executes on several distributed and shared memory computer systems. The coupling method is similar to that used in the NCAR Climate System Model (CSM) in that a flux coupler ties the components together| with interpolations between the different grids of the component models. Flute adjustments are not used in the PCM. The ocean component has 2/3 degrees average horizontal grid spacing with 32 vertical levels and a free surface that allows calculation of sea level changes. Near the equator| the grid spacing is approximately 1/2 degrees in latitude to better capture the ocean equatorial dynamics. The North Pole is rotated over northern North America thus producing resolution smaller than 3/3 degrees in the North Atlantic where the sinking part of the world conveyor circulation largely takes place. Because this ocean model component does not have a computational Feint at the North pole| the Arctic Ocean circulation systems are more realistic and similar to the observed. The elastic viscous plastic sea ice model has a grid spacing of 27 km to represent small-scale features such as ice transport through the Canadian Archipelago and the East Greenland current region. Results from a 300 year present-day coupled climate control simulation are presented| as well as for a transient 1% per year compound CO2 increase experiment which shows a global warming of 1.27 degreesC for a 10 year average at the doubling point of CO2 and 2.89 degreesC at the quadrupling point. There is a gradual warming beyond the doubling and quadrupling points with CO2 held constant. Globally averaged sea level rise at the time of CO2 control simulation are 1% per year transient 1% doubling is approximately 7 cm and at the time of quadrupling it is 23 cm. Some of the regional sea level changes are larger and reflect the adjustments in the temperature| salinity| internal ocean dynamics| surface heat flux| and wind stress on the ocean. A 0.5% per year CO2 increase experiment also was performed showing a global warming of 1.5 degreesC around the time of CO2 doubling and a similar warming pattern to the 1% CO2 per year increase experiment. El Nino and La Nina events in the tropical Pacific show approximately the observed frequency distribution and amplitude| which leads to near observed levels of variability on interannual time scales. 5154,2000,3,3,Peatlands| carbon storage| greenhouse gases| and the Kyoto Protocol: Prospects and significance for Canada,The Kyoto Protocol accepts terrestrial sinks for greenhouse gases (GHGs) as offsets for fossil fuel emissions. Only carbon sequestered in Living biomass from re- and afforestation is presently considered| but the Protocol contains a provision for the possible future inclusion of other land uses and soils. As a result| the possibility of sequestration of carbon in wetlands| and particularly peatlands| is being discussed. Natural peatlands are presently a relatively small sink for CO2 and a large source of CH4: globally| they store between 400 and 500 Gt C. There are large variations among peatlands| but when the "global warming potential" of CH4 is factored in| many peatlands are neither sinks nor sources of GHGs. Some land-use changes may result in peatlands acting as net sinks far GHGs by reducing CH4 emissions and/or increasing CO2 sequestration (e.g.| forest drainage)| while other land uses may result in large losses of CO2| CH4| and N2O (e.g.| agriculture on organic soils| flooding for hydroelectric generation). Other land uses| such as peatland creation and restoration| produce no net change if they are replacing or restoring a previous level of GHG exchange. These are analogous to reforestation of deforested areas. On closer examination| the inclusion of peatlands in a national greenhouse gas strategy as sinks| despite their large role in the terrestrial carbon cycle| may not significantly reduce net greenhouse gas emissons. If the sinks are to be considered| it is reasonable that terrestrial sources associated with all land uses on peatlands also should be considered. If peatlands are not considered explicitly| but soils in forest and agriculture systems are included in the Kyoto Protocol in the future| then those peatlands impacted by these land uses will be incorporated implicitly. 3078,2000,5,4,Periodicity of Holocene climatic variations in the Huguangyan Maar Lake,There exist five primary periods of 2 930| 1 140| 490| 250 and 220 a in the Holocene climatic variations in the Huguangyan Maar Lake| according to the energy-spectrum and filter analyses of high-resolution time sequences (10-15 a) of the sediment dry density. The peak values of the three temperature-decreasing periods with the 2 930 a cycle occur at about 7 300| 4 250 and 1 200 Gal. aBP. There are 7-8 temperature-decreasing periods with the 1 140 a cycle| and the climate fluctuation range is largest in the early Holocene| and reduces gradually in the middle and late Holocene. The millennial-scale climatic change in the Holocene may adjust the global water cycle and the thermohaline circulation intensity through the harmonic tones of the earth's precession cycle| which in turn influences the global climate change. 5339,2000,2,4,Personal protection: The way forward,The perceived need For sunscreens with ever-increasing sun protection factors is unnecessary and leads to more confusion than clarity. Year-round sun protection achieved by the inclusion of ultraviolet (UV) filters in skin care products intended for daily use is not indicated for people living in northern Europe and may| in fact| be potentially harmful. Future needs for sun protection are likely to be influenced more by global warming than ozone depletion| and by the rising trend for overseas holidays to sunny destinations. 5225,2000,3,3,Petroleum industry faces challenge of change in controlling global warming,The Kyoto Protocol| agreed to by more than 160 nations in 1997| represents an enormous challenge to national governments| with vigorous disagreement among the parties regarding the best way to achieve greenhouse gas emissions reductions. Some mechanisms for emissions reduction are of concern to the petroleum industry| including joint implementation| the Clean Development Mechanisms| emissions trading| and carbon sinks generated through land use change and forest management. The negotiating objectives of the EU illustrate how proposals and restrictions might impact companies in the industry. Most observers agree that the Kyoto Protocol is not likely to come into effect in its current form| and that only a few countries can hope to achieve their reduction targets because of major economic concerns. Regardless of the protocol's fate| the challenge remains for the industry to exercise its right and obligation to become part of the solution to climate change.
5326,2000,3,4,Photosynthetic production of microalgal biomass in a raceway system under greenhouse conditions in Sendai city,The photosynthetic productivities of the marine microalgae Chlorophyta sp. and freshwater microalgae Chlorella sp. were investigated in a raceway system under greenhouse conditions in Sendai city. The system was constructed with a surface area of 0.986 m(2) and equipped with paddle wheels (8 fins). The semicontinuous batch culture experiment was carried out for 4 months from June to October 1998 in Sendai city. The productivity of Chlorophyta sp. was ranged from 4 to 13 g(.)m(-2.)d(-1) and the average was 8.2 g(.)m(-2.)d(-1)| which corresponded to the photosynthetic efficiency of 4.15% (PAR). The productivity of Chlorella sp. was ranged from 7 to 21 g(.)m(-2.)d(-1) and the average was 13.2 g(.)m(-2.)d(-1) which corresponded to the photosynthetic efficiency of 6.56% (PAR). These results indicate that stable microalgal cultivation with comparatively high photosynthetic efficiency could be obtained in a raceway system under greenhouse conditions in Sendai city located in the northern part of Japan. 5293,2000,4,4,Photosynthetic responses to a climate-warming manipulation for contrasting meadow species in the Rocky Mountains| Colorado| USA,1. Microclimate was measured and photosynthetic responses to a climate warming manipulation were compared for the evergreen shrub Artemisia tridentata and the herbaceous forb Erigeron speciosus in the Rocky Mountains| Colorado| USA. 2. Soil was warmer and drier under infra-red heaters compared with control plots. 3. Midday xylem pressure potential did not differ for A. tridentata on heated vs control plots but was lower for E. speciosus on heated plots compared with controls. Leaf temperatures did not vary for the two species on heated or control plots. 4. There were no significant treatment or species differences in the diurnal patterns of CO2 assimilation or stomatal conductance to water vapour. Also| there were no differences in responses to leaf temperature. 5. The quantum yield for CO2 assimilation over a range of PPFD was lower for plants on heated plots. There was a marked difference between species in the pattern of stomatal conductance to water vapour over a range of PPFD| but no differences as a result of the heating treatment. 6. The quantum efficiency of PSII electron transport was significantly affected by heating. Non-radiative energy dissipation was greater for A. tridentata compared with E. speciosus. There was recovery of F-V/F-M for A. tridentata but not for E. speciosus. 7. Heating appears to affect plants via changes in soil water content rather than by increasing leaf temperature. The deciduous species E. speciosus appears to undergo some permanent closure of PSII on heated plots| in contrast to the evergreen shrub A. tridentata. Such differences may help explain the increase in above-ground biomass accumulation in response to heating for shrubs| compared with the decrease observed for deciduous herbaceous species. 3136,2000,2,2,Phylogeography and arctic biodiversity: a review,Current concerns over the impact that anthropogenic global climate change will have on levels of biodiversity have focused mainly on tropical and temperate systems. Recently| attention has turned to polar systems| and the potential impacts these climatic changes might have on polar flora and fauna. Polar organisms have been subjected to dramatic fluctuations in environmental conditions during the Holocene and Pleistocene| so one might expect these systems to be resilient. However| little is really known of how such global climate changes will impact biodiversity in the arctic. What is known| particularly through the use of molecular markers| is that glacial cycles have impacted the evolutionary trajectories of many extant polar species. By studying these organisms| particularly those found across the Holarctic| one can examine the dynamic interaction between deterministic forces (e.g. selection) and historical processes (e.g.| vicariance event) in order to better understand how these processes have impacted the phylogeography and genetic divergence among taxa. Keeping with the "northern dimensions" theme of this symposium| we review results obtained from a variety of phylogeographic studies that have examined the importance of dispersal| vicariance| and selection in shaping the distributions of arctic biota| especially among closely-related species complexes. In particular| we examine the recent debate over the importance of Pleistocene glacial cycles in influencing population genetic differentiation and speciation. Finally| we provide an assessment of how studying these arctic systems will benefit the global perspective on climate change research. 5368,2000,3,4,Plasma abatement of perfluorocompounds in inductively coupled plasma reactors,Perfluorinated compounds (PFCs)| gases which have large global warming potentials| are widely used in plasma processing for etching and chamber cleaning. Due to underutilization of the feedstock gases or by-product generation| the effluents from plasma tools using these gases typically have large mole fractions of PFCs. The use of plasma burn-boxes located downstream of the plasma chamber has been proposed as a method for abating PFC emissions with the goals of reducing the cost of PFC abatement and avoiding the NOx formation usually found with thermal treatment methods. Results from the two-dimensional Hybrid Plasma Equipment Model have been used to investigate the scaling of plasma abatement of PFCs using plasma burn-boxes. An inductively coupled plasma (ICP) etching chamber is modeled to determine the utilization of the feedstock gases and the generation of by-products. The effluent from the etching chamber is then passed through a plasma burn-box excited by a second ICP source. O-2| H-2| and H2O are examined as additive gases in the burn-box. We find that C2F6 (or CF4) consumption in the etching reactor increases with increasing ICP power deposition at constant C2F6 (or CF4) mole fraction| and decreasing C2F6 (or CF4) mole fraction or total gas flow rate at constant power. The efficiency of removal of C2F6 (eV/molecule)| however| is strongly dependent only on the C2F6 mole fraction and total gas flow rate. All PFCs in the effluent can generally be abated in the burn-box at high power deposition with a sufficiently large flow of additive gases. In general CF4 generation occurs during abatement of C2F6 using O-2 as an additive. CF4 is not| however| substantially produced when using H-2 or H2O as additives. The efficiency of PFC abatement decreases with increasing power and decreasing additive mole fraction. (C) 2000 American Vacuum Society. [S0734-2101(00)02401-5]. 5180,2000,3,4,Plasma enhanced chemical vapor deposition of thermally stable and low-dielectric-constant fluorinated amorphous carbon films using low-global-warming-potential gas C5F8,Low-dielectric-constant fluorinated amorphous carbon films have been prepared from the low global-warming-potential gas of C5F8 by a capacitively coupled plasma enhanced chemical vapor deposition method. Films were prepared at substrate temperatures as high as 400 degreesC. The obtained deposition rate of 15-65 nm/min was higher than that of conventional C4F8 plasma at the same substrate temperature. The dielectric constant of the films varied from 2.1 to 2.5 with increasing RF power from 10 to 100 W. The residual thickness of the films after 400 degreesC-thermal treatment was higher than 98%. At an RF power higher than 50 W| cracks appeared in the films that were rapidly cooled from 400 degreesC to room temperature| and poor adhesion characteristics were obtained even for the samples without cracks after gradual cooling. On the other hand| the samples prepared at 10 W showed no cracks and good adhesion on a crystalline silicon substrate regardless of the cooling rate. (C) 2000 Elsevier Science S.A. All rights reserved. 5336,2000,2,4,Possible role of climate change in the pollen scatter of Japanese cedar Cryptomeria japonica in Japan,We conducted an atmospheric pollen survey using a Durham sampler from 1983 through 1998 in Toyama City| Japan. We investigated yearly changes in the pollen season of Japanese cedar Cryptomeria japonica and analyzed the relationships between climatic factors and changes in the pollen counts. The results were as follows: (1) The first day of the Japanese cedar pollen season advanced from mid-March to late February. The yearly change in the first day was significantly associated with the mean temperature in February. (2) An increase in total pollen count was significantly associated with the mean temperature in the previous July. (3) The duration of the pollen season was suggested to be associated with the total pollen count. These results indicate that climate change| especially increasing global warming| influences the early pollen scatter and increase in pollen count as well as elongation of pollen season of Japanese cedar. Further study will be needed to clarify its effect on the health of pollen-allergy patients. 5231,2000,2,4,Prediction and prevention of the impacts of sea level rise on the Yangtze River Delta and its adjacent areas,The Yangtze River Delta region is characterized by high density of population and rapidly developing economy. There are low lying coastal plain and deltaic plain in this region. Thus| the study area could be highly vulnerable to accelerated sea level rise caused by global warming. This paper deals with the scenarios of the relative sea level rise in the early half period of the 21st century in the study area. The authors suggested that relative sea level would rise 25-50 cm by the year 2050 in the study area| of which the magnitude of relative sea level rise in the Yangtze River Delta would double the perspective worldwide average. The impacts of sea level rise include: (i) exacerbation of coastline recession in several sections and vertical erosion of tidal flat| and increase in length of eroding coastline; (ii) decrease in area of tidal flat and coastal wetland due to erosion and inundation; (iii) increase in frequency and intensity of storm surge| which would threaten the coastal protection works; (iv) reduction of drainage capacity due to backwater effect in the Lixiahe lowland and the eastern lowland of Taihu Lake region| and exacerbation of flood and waterlogging disasters; and (v) increase in salt water intrusion into the Yangtze Estuary. Comprehensive evaluation of sea level rise impacts shows that the Yangtze River Delta and eastern lowland of Taihu Lake region| especially Shanghai Municipality| belong in the district in the extreme risk category and the next is the northern bank of Hangzhou Bay| the third is the abandoned Yellow River delta| and the district at low risk includes the central part of north Jiangsu coastal plain and Lixiahe lowland. 5264,2000,2,4,Present applications and future needs of meteorological and climatological data in inland fisheries and aquaculture,In 1996 production from capture fisheries and aquaculture in inland waters amounted to more than 23 million t. The amount of fish that can be produced| whether by capture from natural systems| or through aquaculture| depends on water quality and water quantity. The most obvious connections between meteorological data and inland fisheries and aquaculture production are via water temperature and the amounts of water available to natural and man-made systems| but there are also more subtle indirect relationships that affect the movement of nutrients and fish behaviour including migrations and reproduction. A wide range of examples of applications of meteorological data to aquaculture and inland fisheries are provided. They include continental assessments of inland fish farming potential| fishery potential in small water bodies| synoptic loss of fishery potential due to environmental degradation| complex effects of wind on fish production in a large lake and effects of global warming on fish distribution and production. It is concluded that the meteorological data that serve for agriculture also are relevant for inland fisheries and aquaculture| although the relative importance of parameters and their temporal aptness may be different| and thresholds may be dissimilar. Similarly| if the timeliness| resolution and predictive capabilities for agrometeorological data can be improved| there would be considerable benefits to inland fisheries and aquaculture. Geographically synoptic gridded agrometeorological data sets at 1 km resolution should be a short term objective. (C) 2000 Elsevier Science B.V. All rights reserved. 5259,2000,3,4,Present status of amorphous soft magnetic alloys,Application of amorphous soft magnets in electric-utility and industrial transformers are increasingly being adopted| helping to solve global warming and energy-saving problems. Tn addition| amorphous metal-based magnetic components are used in power electronics| telecommunication equipment| sensing devices| electronic article surveillance systems| etc. Some magnetic inductors find applications in pulse power devices| automotive ignition coils| and electric power conditioning systems. All of these applications are possible because of faster flux reversal| lower magnetic loss and more versatile property modification achievable in amorphous alloys. Improvements in materials processing and device Fabrication technology will continue to lake place| which will further increase the universe of application of amorphous soft magnets. Some fundamental problems associated with the applications are mentioned. (C) 2000 Elsevier Science B.V. All rights reserved. 5186,2000,2,3,Preserving the ocean circulation: Implications for climate policy,Climate modelers have recognized the possibility of abrupt climate changes caused by a reorganization of the North Atlantic's current pattern (technically known as a thermohaline circulation collapse). This circulation system now warms north-western Europe and transports carbon dioxide to the deep oceans. The posited collapse of this system could produce severe cooling in northwestern Europe| even when general global warming is in progress. In this paper we use a simple integrated assessment model to investigate the optimal policy response to this risk. Adding the constraint of avoiding a thermohaline circulation collapse would significantly reduce the allowable greenhouse gas emissions in the long run along an optimal path. Our analysis implies that relatively small damages associated with a collapse (less than 1% of gross world product) would justify a considerable reduction of future carbon dioxide emissions. 3097,2000,2,4,Prevalence of malaria parasites (Plasmodium floridense and Plasmodium azurophilum) infecting a Puerto Rican lizard (Anolis gundlachi): A nine-year study,The prevalence of malaria parasites was studied in the lizard Anolis gundlachi over a 9-yr period at a site in the wet evergreen forest of eastern Puerto Rico. Three forms of the parasite infected the lizards: these were Plasmodium floridense| Plasmodium azurophilum in erythrocytes| and P. azurophilum in white blood cells. Overall prevalence of infection for 8 samples during the study period was significantly higher for males than females (32% of 3|296 males and 22% of 1.439 females). During the study| the site experienced substantial climatic and physical disturbance including rising temperature| droughts| and hurricanes that severely damaged the forest. Parasite prevalence in the first sample| 8 mo after the massive hurricane Hugo| was slightly| though significantly| lower than for subsequent samples. However| overall prevalence was stable during the 9-yr period. The results show malaria prevalence is more constant at the site than found for 2 studies in temperate forests| and that the Puerto Rico system may be an example of the stable| endemic malaria described by standard models for human malaria epidemiology. 3058,2000,5,4,Quaternary chronostratigraphy: the nomenclature of terrestrial sequences,There is a long-standing tradition of dividing Quaternary stratigraphical sequences on the basis of climate. This climatostratigraphical approach| begun on terrestrial sequences in the last century| led to the widespread adoption of glacial| interglacial| stadial and interstadial subdivisions as standard. However| the limitations of the approach resulted in its replacement by local sequences of chronostratigraphical stages from the 1950s. The subsequent establishment of the detail and complexity of ocean-core sequences has encouraged increasing use of the terminology developed for these records to the terrestrial and shallow marine succession. The view is expressed that it is advisable to separate and retain regional chronostratigraphies for each sequence-type| and that these should be correlated using event-based stratigraphy where possible. This should ensure both the highest precision and lack of ambiguity and a securely-based synthesis of the relations between the terrestrial and ocean isotope sequences| a synthesis which is fundamental to understanding the nature and detail of regional and global climate change. 5236,2000,3,4,Radiative forcing and global warming potentials of 11 halogenated compounds,Radiative forcing values have been calculated for 11 halogenated compounds which are in current use or which have been suggested as possible replacements for the chlorofluorocarbons. Absorption cross-sections measured over a range of atmospheric temperature and pressure conditions as part of a multi-laboratory programme have been used together with a narrow band radiative transfer model. We provide a "best estimate" radiative forcing taking into account the likely vertical profile of the gas in each case. The Global Warming Potential over a variety of time horizons has also been calculated where the lifetime is available. We present the first such information for 1|2-dichloroethane. For chloroform our radiative forcing is 5 times higher than the value used in previous assessments| possibly because these ignored the effect of absorption outside the 800-1200 cm(-1) "window". For several of the other compounds considered here| our forcing is between 10 and 30% lower than previous assessments. The perfluorocarbons have been found to have large global warming potentials| many times that of CFC-11| due to both strong absorption and long lifetimes. The importance of absorption features at wavenumbers below 800 cm(-1) and the effect of temperature variations in absorption cross-section on the radiative forcing are also investigated. (C) 2000 Elsevier Science Ltd. All rights reserved. 5226,2000,4,1,Radiative forcings and global warming potentials of 39 greenhouse gases,The radiative forcings and global warming potentials for 39 greenhouse gases are evaluated using narrowband and broadband radiative transfer models. Unlike many previous studies| latitudinal and seasonal variations are considered explicitly| using distributions of major greenhouse gases from a combination of chemical-transport model results and Upper Atmosphere Research Satellite (UARS) measurements and cloud statistics from the International Satellite Cloud Climatology Project. The gases examined include CO2| CH4| N2O| plus a number of chlorofluorocarbons| hydrochlorofluorocarbons| hydrofluorocarbons| hydrochlorocarbons| bromocarbons| iodocarbons| and perfluorocarbons (PFCs). The model calculations are performed on a 5 degrees latitude grid from 82.5 degrees S to 82.5 degrees N. The radiative forcings determined by the model are then used to derive global warming potential for each of the compounds| which are compared with prior analyses. In addition| the latitudinal and seasonal dependence of radiative forcing since preindustrial time is calculated. The vertical profiles of the gases are found to be important in determining the radiative forcings; the use of height-independent vertical distributions of greenhouse gases| as used in many previous studies| produce errors of several percent in estimated radiative forcings for gases studied here; the errors for the short-lived compounds are relatively higher. Errors in evaluated radiative forcings caused by neglecting both the seasonal and the latitudinal distributions of greenhouse gases and atmospheres are generally smaller than those due to height-independent vertical distributions. Our total radiative forcing due to increase ill major greenhouse gas concentrations for the period 1765-1992 is 2.32 Wm(-2)| only 2% higher than other recent estimates; however| the differences for individual gases are as large as 23%. 5296,2000,4,4,Rate constant for the reactions of CF3OCHFCF3 with OH and Cl,The kinetics of reactions of CF3OCHFCF3 with hydroxyl radicals and chlorine atoms has been investigated using a discharged flow combined with both mass spectrometer and resonance fluorescence technique and using a relative rate technique| respectively| at 298 K. The rate constant for the reactions of CF3OCHFCF3 with OH and Cl was determined to be k(1) = (4.98 +/- 1.64) X 10(-15) cm(3) molecule(-1) s(-1) and k(2) = (3.1 +/- 2.5) X 10(-14) cm(3) molecule(-1) s(-1)| respectively. On the basis of our kinetics measurements| the tropospheric lifetime of CF3OCHFCF3 is calculated to be about 8 years| primarily due to reaction with the hydroxyl radicals in the troposphere. (C) 2000 Elsevier Science B.V. All rights reserved. 3082,2000,2,4,Reanalyses-based tropospheric temperature estimates: Uncertainties in the context of global climate change detection,Uncertainties in estimates of tropospheric mean temperature were investigated in the context of climate change detection through comparisons of the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) 40-yr reanalysis (1958-97)| the National Aeronautics and Space Administration Data Assimilation Office (NASA/DAO) 14-yr reanalysis (1980-93)| the European Centre for Medium-Range Weather Forecasts Reanalysis Project (ERA) 15-yr reanalysis (1979-94)| and the satellite microwave sounding unit channel 2 (MSU Ch2) (1979-97) temperature data. The maximum overlap period for comparison among these datasets is the 14 full years January 1980 to December 1993. This study documents similar shifts in the relative bias between the MSU Ch2 and the ERA and the NCEP-NCAR reanalyses in the 1991-97 period suggesting changes in the satellite analysis. However| the intercomparisons were not able to rule out the changes in the reanalysis systems and/or the input data on which the reanalyses are based as prime factors for the changes in the relative bias between the MSU and ERA and NCEP-NCAR reanalyses. These temporal changes in the relative bias among the reanalyses suggest their limitations for global change studies. Nonetheless| the analysis also shows that the pattern correlations (r) between the MSU Ch2 monthly mean fields and each of the reanalyses are very high| r > 0.96| and remain relatively high for the anomaly fields| r > 0.8| generally >0.9. This result suggests that reanalysis may be used for comparisons to numerical model-generated forecast fields (from GCM simulation runs) and in conjunction with "fingerprint'" techniques to identify climate change. In comparisons of the simple linear trends present in each dataset for the 1980-90 period| each of the reanalyses had spatial patterns similar to MSU Ch2 except that the NCEP-NCAR reanalysis showed smaller "positive" (warming) trends in comparison with the MSU while the ERA reanalysis showed larger positive trends. The NASA/DAO reanalysis showed a mixed pattern. Many regions of the globe are identified that showed consistent warming/cooling patterns among the major reanalyses and MSU| even though there were disagreements in the exact magnitude among the analyses. The spatial patterns of linear trends changed| however| with the addition of three years of data to extend the trend analysis to the 1980-93 period. This result suggests that such simple linear trend analyses are very sensitive to the temporal span in these relatively shea datasets and thus are of limited usefulness in the context of climate change detection except| however| when the signal is large and shows consistency among all datasets. The long record (1958-96) of seasonal mean 2-m temperature anomalies from NCEP-NCAR reanalysis is well correlated with gridded analyses of station-based observed surface temperature| with correlations between 0.65 and 0.85. It is argued that these correlations might suggest an upper limit to the magnitudes of the pattern correlations that might be obtained by correlating observed surface temperature analyses with those from multiyear GCM simulation runs made in the context of fingerprint climate change detection. 5375,2000,5,1,Recent warming in a 500-year palaeotemperature record from varved sediments| Upper Soper Lake| Baffin Island| Canada,Laminated sediments from Upper Soper Lake on southern Baffin island provide a new 500-year record of temperature change in the Arctic. Radiometric dating| using Pb-210 and Pu| shows that the light- and dark-coloured laminae couplets are annually deposited varves. Dark laminae thickness is strongly correlated to average June temperature from Kimmirut (r = 0.82)| reflecting the influence of temperature on snowmelt and fluxes of runoff and suspended sediment. This relationship allowed the construction of a palaeotemperature record that documents large-amplitude interannual to decadal variability superimposed on distinct century-scale trends| including 2 degrees C average warming and maximum temperatures during the 1900s. Similar patterns of change are seen in individual and regionally averaged palaeotemperature records from around the circum-Arctic. Upper Soper Lake records temperatures| rates of change and Variance during the twentieth century that are all anomalously high within the context of the last 500 years| and outside the observed range of natural variability. Comparisons of Upper Soper Lake and Arctic average palaeotemperature to proxy-records of hypothesized forcing mechanisms suggest that the recent warming trend is mostly due to anthropogenic emissions of atmospheric greenhouse gases. The magnitude of the warming and decade-scale variability throughout the records| however| indicate that natural forcing mechanisms such as changing solar irradiance and volcanic activity| as well as positive feedbacks within the Arctic environment| also play an important role. 5354,2000,3,3,Reduction of iron-oxide by ball-milling with hydrogen gas flow,A new method for reducing iron-ore without greenhouse effect gas exhaust was developed to prevent the global warming. The reduction of alpha-Fe2O3 (hematite) by ball-milling with hydrogen gas flow was studied by XRD| SEM| TEM and Mossbauer spectroscopy. Iron oxide (alpha-Fe2O3) powder was charged into a container for ball-milling with stainless steel balls. The container was designed to flow gas during ball-milling process. It has two holes| one of which is for inducing hydrogen gas into container| other one is for exhausting a producing gas out of the container. Milling was interrupted to take samples for estimating the deoxidization process. Charging and removal of the samples were done in a high purity argon atmosphere. A vibrating ball-mill machine was used. The results of X-ray diffraction measurement show that the reduction of iron-oxide starts at 18.0 ks of ball-milling. The intensity of Bragg peaks corresponding to the Fe2O3 decreased with milling time. Conversely to this| the intensity of Bragg peaks of alpha-Fe increased. At 216.0 ks of milling| almost the Bragg peaks of Fe2O3 disappeared and the only Bragg peaks of alpha-Fe remained. During this reducing process| Fe3O4 and FeO appeared as intermediate states between alpha-Fe2O3 and alpha-Fe. Nano-crystalline Fe was obtained by the reduction of iron-oxide by ball-milling with hydrogen gas flow. 5220,2000,3,4,Refrigerant use in Europe,The environmental issues of ozone depletion and global warming have considerably affected the refrigeration| air-conditioning and heat pump industry over the last 10 years. The Montreal Protocol has caused the refrigeration industry to introduce newly developed hydrofluorocarbons (HFCs) as substitutes for the chlorine-containing| ozone-depleting chlorofluorocarbons (CFCs). This process for new systems has been finalized in industrialized countries and is ongoing in developing countries. Hydrochlorofluorocarbons (HCFCs)| such as R-22| have much lower ozone-depleting potential (ODP) and will be phased out within the next 20 years worldwide. However| national regulations require a much earlier phase-out date| especially in Europe. Therefore| chlorine-free HFCs will replace chlorine-containing refrigerants in the marketplace. 3121,2000,2,4,Regional climate change: Trend analysis of temperature and precipitation series at selected Canadian sites,Global climate change does not necessarily imply that temperature or precipitation is increasing at specific locations. The hypothesis of increasing temperature and precipitation trends associated with global climate change is tested using actual annual temperature and precipitation data for nine selected weather stations| spatially distributed across Canada. Vogelsang's (1998) partial sum and Woodward et al's (1997) bootstrap methods are used for testing for trend Both methods suggest no warming in the Canadian temperature series except for Toronto| Ontario| which had significant increase over time| along with Moncton| New Brunswick and Indian Head| Saskatchewan| which had marginal increases. There is no evidence of increasing trend in precipitation except for Moncton| New Brunswick| which had a significantly increasing trend| thus| public policies designed to address the regional effects of climate change need to be adapted for a particular ecological zone| based on knowledge of the climate trends for that region| rather than on general global climate change patterns. 5346,2000,2,4,Remedial habitat creation: does Nereis diversicolor play a confounding role in the colonisation and establishment of the pioneering saltmarsh plant| Spartina anglica?,Increasing concerns over global warming and expected sea level rises have led to the adoption of new coastal management strategies around the south-east roast of England. This paper explores the role played by the estuarine invertebrate Nereis diversicolor in limiting the colonisation and establishment of the invasive pioneering salt marsh plant| Spartina anglica. The biology of N. diversicolor is brief-iv reviewed and data from field experiments are presented demonstrating significant negative effects of worm abundance on transplanted S. anglica biomass. Laboratory-based experiments demonstrated significant negative effects of N. diversicolor abundance on the survival of S. anglica seeds transplanted to sediment cores. The importance of estuarine invertebrates in engineering the mudflat habitat may confound the foreseen ecosystem services and function provided by saltmarsh management schemes. 5289,2000,3,4,Reservoir-engineering aspects of CO2 sequestration in coals,Increasing worldwide CO2 emissions have heightened interest in injecting CO2 into coals to mitigate ifs possible role in global-warming. Concepts from natural gas storage are readily adapted to CO2 sequestration in coal. Coal-seam fill-up with CO2 can be described by coupling a gas-injectivity equation with a mass-balance equation. The full-length paper presents example calculations for two selected coal basins. 3101,2000,2,4,Respondence and feedback of modern sand deserts to climate change - A case study in Gurbantunggut Desert,The research on the respondence and feedback of modern sand deserts to the climate change is an important component part in the studies on the global climate change| Deserts respond to the climate change| meanwhile| they affect the climate with their feedback of peculiar environment during the respondence. Many researches on desert climate have been carried out at home and abroad. However| there is little research on the respondence and feedback of modern fixed| semi-fixed and mobile deserts in arid areas to the climate change| in which the factor analysis as well as the parameter changing effects is especially the difficult problem all along. In this note| the parameters of the respondence and feedback of Gurbantunggut Desert to the climate change are measured and analyzed| some variable parameters of water-heat exchange are obtained| and a numerical model of desertification is developed according to a series of climate change of about 40 years and the variable relations of meteorological and physical features of the sand surface in Gurbantunggut Desert. 5208,2000,2,4,Response of atmospheric methane consumption by Maine forest soils to exogenous aluminum salts,Atmospheric methane consumption by Maine forest soils was inhibited by additions of environmentally relevant levels of aluminum. Aluminum chloride was more inhibitory than nitrate or sulfate salts| but its effect was comparable to that of a chelated form of aluminum. Inhibition could be explained in part by the lower soil pH values which resulted from aluminum addition. However| significantly greater inhibition by aluminum than by mineral acids at equivalent soil pH values indicated that inhibition also resulted from direct effects of aluminum per se. The extent of inhibition by exogenous aluminum increased with increasing methane concentration for soils incubated in vitro. At methane concentrations of >10 ppm| inhibition could be observed when aluminum chloride was added at concentrations as low as 10 nmol g (fresh weight) of soil(-1). These results suggest that widespread acidification of soils and aluminum mobilization due to acid precipitation may exacerbate inhibition of atmospheric methane consumption due to changes in other parameters and increase the contribution of methane to global warming. 5143,2000,2,4,Response of bog and fen plant communities to warming and water-table manipulations,Large-scale changes in climate may have unexpected effects on ecosystems| given the importance of climate as a control over almost all ecosystem attributes and internal feedbacks. Changes in plant community productivity or composition| for example| may alter ecosystem resource dynamics| trophic structures| or disturbance regimes| with subsequent positive or negative feedbacks on the plant community. At northern latitudes| where increases in temperature are expected to be greatest but where plant species diversity is relatively low| climatically mediated changes in species composition or abundance will likely have large ecosystem effects. In this study| we investigated effects of infrared loading and manipulations of water-table elevation on net primary productivity of plant species in bog and fen wetland mesocosms between 1994 and 1997. We removed 27 intact soil monoliths (2.1 m(2) surface area| 0.5-0.7 m depth) each from a bog and a fen in northern Minnesota to construct a large mesocosm facility that allows for direct manipulation of climatic variables in a replicated experimental design. The treatment design was a fully crossed factorial with three infrared-loading treatments| three water-table treatments| and two ecosystem types (bogs and fens)| with three replicates of all treatment combinations. Overhead infrared lamps caused mean monthly soil temperatures to increase by 1.6-4.1 degreesC at 15-cm depth during the growing season (May-October). In 1996| depths to water table averaged -11| -19| and -26 cm in the bog plots| and 0| -10| and -19 cm in the fen plots. Annual aboveground net primary production (ANPP) of bryophyte| forb| graminoid| and shrub life-forms was determined for the dominant species in the mesocosm plots based on species specific canopy/biomass relationships. Belowground net primary production (BNPP) was estimated using root in-growth cores. Bog and fen communities differed in their response to infrared loading and water-table treatments because of the differential response of life-forms and species characteristic of each community. Along a gradient of increasing water-table elevation| production of bryophytes increased| and production of shrubs decreased in the bog community. Along a similar gradient in the fen community| production of graminoids and forbs increased. Along a gradient of in creasing infrared loading in the bog| shrub production increased whereas graminoid production decreased. In the fen| graminoids were most productive at high infrared loading| and forbs were most productive at medium infrared loading. In the bog and fen| BNPP:ANPP ratios increased with warming and drying| indicating shifts in carbon allocation in response to climate change. Further| opposing responses of species and life-forms tended to cancel out the response of production at higher levels of organization| especially in the bog. For example| total net primary productivity in the bog did not differ between water-table treatments because BNPP was greatest in the dry treatment whereas ANPP was greatest in the wet treatment. The differential responses of species| life-forms| and above- and belowground biomass production to the treatments suggest that bog and fen plant communities will change| in different directions and magnitudes| in response to warming and changes in water-table elevation. Further| results of this and complementary research indicate that these peatlands may mediate their energy| carbon| and nutrient budgets through differential responses of the plant communities. Thus| predictions of the response of peatlands to changes in climate should consider differences in plant community structure| as well as biogeochemistry and hydrology| that characterize and differentiate these two ecosystems. 5374,2000,5,4,Response of climate to solar forcing recorded in a 6000-year delta O-18 time-series of Chinese peat cellulose,Previous studies have shown that the oxygen isotope ratio (delta(18)O) of plant cellulose can serve as a sensitive proxy indicator of past climate| but its application has mainly been restricted to tree-rings. Here we present a 6000-year high-resolution delta(18)O record of peat plant cellulose from northeastern China. The delta(18)O Variation is interpreted as reflecting changes in regional surface air temperature. The climate events inferred from the isotope data agree well with archaeological and historic evidence. The record shows a striking correspondence of climate events to nearly all of the apparent solar activity changes characterized by the atmospheric radiocarbon in tree-rings over the past 6000 years. Spectral analysis of the delta(18)O record reveals the periodicities of around 86| 93| 101| 110| 127| 132| 140| 155| 207| 245| 311| 590| 820 and 1046 years| which are similar to those detected in the solar excursions. We consider these observations as further evidence for a close relationship between solar activity and climate variations on timescales of decades to centuries. Our results also have implications for distinguishing between natural and anthropogenic contributions to future climate change. 5263,2000,4,1,Response of the NCAR climate system model to increased CO2 and the role of physical processes,The global warming resulting from increased CO2 is addressed in the context of two regional processes that contribute to climate change in coupled climate models| the "El Nino-like" response (slackening of the equatorial Pacific SST gradient) and sea-ice response at high latitudes. The National Center for Atmospheric Research (NCAR) Climate System Model (CSM) response is compared with results from a coupled model that produces comparatively greater global warming| the NCAR U.S. Department of Energy (DOE) global coupled model. In an experiment where atmospheric CO2 is increased 1% yr(-1) compound| globally averaged surface air temperature increase near the time of CO2 doubling for the CSM is 1.43 degrees C (3.50 degrees C for the DOE model). Analysis of a simple coupled model shows the CSM equilibrium sensitivity to doubled CO2 is comparable to that from the slab ocean version (about 2.1 degrees C). One process that contributes to global warming (estimated to be about 5% in one slab ocean model)| as well as to significant Pacific region climate effects| is the El Nino-like response. It is a notable feature in the DOE model and some other global coupled models but does not occur in the CSM. The authors show that cloud responses are a major determining factor. With increased CO2| there are negative net cloud-forcing differences in the western equatorial Pacific in the CSM and DOE models| but large positive differences in the DOE model and negative differences in the CSM in the eastern equatorial Pacific. This produces asymmetric cloud radiative forcing contributing to an El Nino-like response in the DOE model and not in the CSM. To remove the amplifying effects of ocean dynamics and to identify possible parameter-dependent processes that could contribute to such cloud forcing changes| the authors analyze slab ocean versions of the coupled models in comparison with a slab ocean configuration of the atmospheric model in the CSM [Community Climate Model Version 3 (CCM3)] that includes prognostic cloud liquid water. The latter shows a change in sign (from negative to positive) of the net cloud forcing in the eastern equatorial Pacific with doubled CO2| similar to the DOE model| in comparison with the CCM3 version with diagnostic cloud liquid water. Atmospheric Model Intercomparison Project (prescribed SST) experiments show that ail three atmospheric models (DOE| CCM3 with diagnostic cloud liquid water| and CCM3 with prognostic cloud liquid water) perform poorly relative to observations in terms of cloud radiative forcing| though CCM3 with prognostic cloud liquid water is slightly superior to the others. Another process that contributes to climate response to increasing CO2 is sea-ice changes| which are estimated to enhance global warming by roughly 20% in the CSM and 37% in the DOE model. Sea-ice retreat with increasing CO2 in the CSM is less than in the DOE model in spite df identical sea-ice formulations. Results from the North Atlantic and Greenland-Iceland-Norwegian (GIN) Sea region show that the surface energy budget response is controlled primarily by surface albedo (related to ice area changes) and cloud changes. However| a more important factor is the poleward ocean heat transport associated with changes in meridional overturning in the GIN Sea. With increased CO2| the transport of warmer water from the south into this region in the DOE model is greater in comparison with that of the CSM. This leads to a larger ice reduction in the DOE model| thus also contributing to the enhanced contribution from ice albedo feedback in the DOE model in comparison with the CSM. 5266,2000,2,4,Responses of subalpine meadow vegetation to four years of experimental warming,Ecosystems at high elevations may be especially sensitive to global warming| because productivity is limited to a snow-free growing season| and warming is expected to cause earlier snowmelt. Here we report on vegetation responses to experimental warming in a subalpine meadow in the Colorado Rocky Mountains. We found no evidence that the plant community changed during four years of warming. Species composition in warmed plots did not change more through time than in control plots| nor did warmed plots diverge from adjacent control plots through time. Contrary to an earlier report| we found no evidence that warming facilitated adults or seedlings of sagebrush| a shrub characteristic of lower elevation ecosystems; nor did it facilitate short-lived plant species as a group. Total vegetation cover| as well as cover of graminoids| forbs| and shrubs| did not differ between control and warmed plots| nor did species richness or species' distributions along a small elevational gradient within each plot. Shrub cover tended to increase more| and forb cover to decrease more| in warmed than in control plots during one summer season| but not significantly so. This lack of detectable plant community response contrasts with pronounced responses to warming in some arctic and alpine ecosystems over similar time spans. Warming in these ecosystems is thought to act indirectly via increased mobilization of soil nutrients. One possible reason for the lack of response in our system is that drying of soil limits microbial activity| photosynthesis| and plant growth sooner in the season in warmed plots| canceling out effects of earlier snowmelt. If this is correct| and if summer precipitation patterns are unchanged under global warming| then vegetation in arid high-elevation ecosystems may change only slowly. 3056,2000,2,4,Scaling phenology from the local to the regional level: advances from species-specific phenological models,Plant phenology| the study of seasonal plant activity driven by environmental factors| has found a renewal in the context of global climate change. Phenological events| such as leaf unfolding| exert strong control over seasonal exchanges of matter and energy between the land surface and the atmosphere. Phenological models that simulate the start of the growing season should be efficient tools to predict vegetation responses to climatic changes and related changes in energy balance. Species-specific phenological models developed in the eighties have not been used for global-scale predictions because their predictions were inaccurate in external conditions. Recent advances in phenology modelling at the species level suggest that prediction at a large scale may now be possible. In the present study| we tested the performance of species-specific phenological models in time and space| looking at their ability (i) to predict regional phenology when previously fitted at a local scale| and (ii) to predict phenological trends| linked to climate changes| observed over a long-term. For that task we used an historical phenological dataset from Ohio from the late ninetieth century and an airborne pollen dataset from Ontario| Quebec and Maryland from the late twentieth century. The results show that the species-specific phenological models used in this study were able to predict regional phenology even though they were fitted locally. The reconstruction of a phenological time series over the twentieth century showed a significant advancement of 0.2 days per year in the date of flowering of Ulmus americana| but very weak trends for Fraxinus americana and Quercus velutina. 5376,2000,3,4,Screening pumping systems for energy savings opportunities,In most industrial settings| energy consumed by pumping systems is responsible for a major part of the overall electricity bill. In some cases| the energy is used quite efficiently; in others| it is not. Facility operators may be very familiar with pumping system equipment controllability| reliability| and availability| but only marginally aware of system efficiency. But there are some good reasons to increase that awareness: 1) As budgets shrink and the intensity of both domestic and international competition increases| the pressure to find additional of reducing costs will grow. 2) The reliability of pumps correlates with pump efficiency; that pumps operated near the design| or best efficiency point| will to perform more reliably and with greater availability. 3) The questions of whether global warming is truly occurring| and it is| whether humankind's activities play a significant role| both be debatable. But there is no debating the fact that there finite energy resources| particularly of the fossil fuel variety| on earth. If we are to be counted as good stewards| then careful| if frugal| resource use is important. The cost of energy consumed by pumps usually dominates the pump life cycle cost. But many end users| already stretched to support day-to-day facility operations| lack the time and resources to perform a methodical engineering study of| in some cases| hundreds of pumps within their facilities to understand the energy costs and the potential opportunity for reduction. Under the auspices of the Department of Energy's (DOE) Motor Challenge Program| prescreening guidance documents and a computer program called PSAT (pumping system assessment tool) have been developed to help end users| consultants| and equipment distributors recognize| both qualitatively and quantitatively| pumping system efficiency improvement opportunities. This article describes the general methodologies employed and shows case study examples of the prescreening and software application.
5314,2000,2,4,Seasonal and altitudinal variation in decomposition of soil organic matter inferred from radiocarbon measurements of soil CO2 flux,The rate of carbon (C) cycling in soils is controlled by an array of processes and conditions. It has been widely accepted that an increase in temperature would accelerate microbial decomposition of soil organic matter (SOM) and provide a positive feedback to global warming| other factors being equal. However| soil moisture has received little attention in C cycle studies. In this project| we developed a technique for sampling soil-respired CO2 for isotopic measurements and a model that relates the radiocarbon (C-14) content of soil respired CO2 to the rate of C cycling in soils. We measured soil CO2 flux| carbon isotopic content (both C-13 and C-14) of soil-respired CO2| soil temperature| and soil moisture on a monthly basis along an elevation transect in the Sierra Nevada in an attempt to determine the relationship between the rate of soil C cycling and soil environmental conditions. Both soil CO2 flux and its C-14 content displayed significant variations (spatially and temporally)| which reflect natural variations in the rate of SOM decomposition and in the relative amount of SOM-derived CO2 versus root-respired CO2 caused by seasonal changes in soil temperature| moisture| and plant activity. The relative contribution of SOM decomposition to total soil CO2 production changed throughout the year from similar to 20 - 50% at the peak of the growing season to close to 100% in the nongrowing season. The apparent decay rate of SOM determined from the C-14 content of soil-respired CO2 varied from similar to 0.2 yr(-1) in the spring to similar to 0.01 yr(-1) in the fall at the lowest-elevation site and from 0.1 yr(-1) in the summer to - 0.01 yr(-1) in the late fall at the highest-elevation site. It appears that the apparent decay rate of SOM increased with increasing temperature when soil moisture was adequate but decreased with increasing temperature when soil moisture became limited. The apparent decay rate of SOM also varied with soil moisture. Higher soil moisture content accelerated decomposition of SOM until it reached an optimal level of similar to 14 - 25 wt % water content and then inhibited decomposition when more pores in soils became saturated with water and perhaps oxygen availability (for microbes) became limited. Although the rate of SOM decomposition varied throughout the year in response to fluctuations in soil temperature and moisture| the maximum apparent decay rate was higher at the low-elevation site (i.e.| maximum apparent decay rate = 0.22 yr(-1)) than at the high-elevation sites (i.e.| maximum apparent decay rate = 0.10 yr(-1)). Litter decomposition simulated by measuring changes in mass of litter in litter bags placed in the field also showed a similar decomposition pattern with decreasing decomposition rate with elevation. Multivariable regression analyses including various terms of soil temperature| moisture| and site variability suggest that soil moisture was a major factor| but not the only factor| controlling the rate of SOM decomposition and soil CO2 flux in the Sierra Nevada soils. Both decay rate and total soil CO2 flux are related significantly to soil moisture| temperature| and site effects. 5262,2000,2,4,Seed bank dynamics: the role of fungal pathogens and climate change,1. One of the climate change scenarios predicted for the UK is warmer winters and additional summer rainfall| which may favour growth and survival of fungal pathogens. We tested several hypotheses on the fate of persistent seeds in the soil and the role of fungal pathogens under this predicted climate change. 2| We buried seed bags containing fungicide-treated and non-fungicide-treated seeds of four species with persistent seed banks (Convolvulus arvensis L.| Lotus corniculatus L.| Medicago lupulina L. and Rubus fruticosus L.) under control and simulated climate change (winter warming plus supplemented summer rain) conditions| and monitored seed survival over 1 to 2 years. 3. Fungicide treatment resulted in a significant increase in the percentage of intact seeds recovered for only two of the four species| M. lupulina and R. fruticosus. Seeds of M. lupulina that were treated with fungicide remained viable in the soil for longer than non-treated seeds. Thus| the effect of fungal pathogens on seed persistence in the soil appears to be species specific. 4. There was no significant effect of the simulated climate (winter warming plus supplemented summer rain) on seed persistence in the soil| for any of the four species. Neither was a significant climate x fungicide treatment interaction found for any of the four species. Thus| it does not appear that the conditions provided in the simulated climate plots favoured the growth and survival of fungal pathogens affecting the soil seed banks of the four species studied here. 5. The use of fungicides in manipulative experiments and the importance of field experiments that simulate predicted climate change are discussed. 5153,2000,2,4,Selection of white spruce families in the context of climate change: heat tolerance,To assess the responses and plasticity of white spruce seedlings (Picea glauca (Moench) Voss) to high temperatures| 12 open-pollinated families differing in growth performance were exposed to a 30-min heat treatment of 42| 44| 46| 48| or 50 degreesC with or without heat preconditioning at 38 degreesC for 5 h. Damage was evaluated based on chlorophyll fluorescence parameters after heat preconditioning| after the heat treatments and during a 7-day recovery period. Visible needle damage was also evaluated after the heat treatments and 14 days later. Chlorophyll fluorescence parameters indicated that seedlings subjected to a heat treatment of 42-43 degreesC lost the ability to phosphorylate and donate water to photosystem II (PSII). A heat treatment of 44-46 degreesC severely limited the ability of the seedlings to use NADPK and ATP in the Calvin cycle. Based on visible needle damage| families with superior height-growth performance were more sensitive to heat stress than families with intermediate or inferior height-growth performance. Moreover| families with superior height-growth performance had low photochemical efficiencies in the light (DeltaF/F-m') after heat treatment. Heat preconditioning increased the thermotolerance of the seedlings. However| the data suggest that white spruce seedlings exhibiting fast-growing characteristics under present conditions may not grow as well at higher temperatures. 5364,2000,2,3,Sensitivity of modern and Holocene floods to climate change,Alluvial records of paleofloods show that natural floods resulting from excessive rainfall| snowmelt| or from combined rainfall and snowmelt are highly sensitive to even modest changes of climate equivalent or smaller than changes expected from potential future global warming in the 21st century. The high sensitivity results from effects of hemispheric or global-scale changes in circulation patterns of the ocean and atmosphere to influence the pathway's and locations of air masses and storm tracks. Holocene paleoflood chronologies from the Upper Mississippi Valley in the Midwest United States and from the Colorado River drainage of the Southwest United States show that recurrence frequencies of large floods have been subject to abrupt changes over time. These flood chronologies and hood chronologies observed for other middle-latitude regions suggest that recurrence frequencies of large hoods are increased when there is an increase in the number of waves and their amplitudes in the middle and upper tropospheric circum-polar westerly circulation. However| some middle-latitude regions on the western margins of continents experience increased frequencies of flooding during strong onshore zonal westerly circulation. Flood chronologies from several regions suggest that times of rapid climate change have a tendency to be associated with more frequent occurrences of large and extreme floods. The unusual high frequencies of large floods that have been observed in many regions since the early 1950s are often attributed to land use change| but the rapid climate forcing from the effects of increased atmospheric greenhouse gases may also be a contributing factor. Paleoflood records provide information that is useful for better interpretation and calibration of modern short-term instrumental records| and they provide unique event-scale information that is useful fbr calibrating and testing geophysical models of past and anticipated future climate conditions. (C) 1999 Elsevier Science Ltd. All rights reserved. 3083,2000,2,4,Sensitivity of three grassland communities to simulated extreme temperature and rainfall events,Three grassland communities in New Zealand with differing climates and proportions of C3 and C4 species were subjected to one-off extreme heating (eight hours at 52.5 degrees C) and rainfall (the equivalent of 100 mm) events. A novel experimental technique using portable computer-controlled chambers simulated the extreme heating events. The productive| moist C3/C4 community was the most sensitive to the extreme events in terms of short-term community composition compared with a dry C3/C4 community or an exclusively C3 community. An extreme heating event caused the greatest change to plant community species abundance by favouring the expansion of C4 species relative to C3 species| shifting C4 species abundance from 43% up to 84% at the productive| moist site| This was observed both in the presence and absence of added water. In the absence of C4 species| heating reduced community productivity by over 60%. The short-term shifts in the abundance of C3 and C4 species in response to the single extreme climatic events did not have persistent effects on community structure or on soil nitrogen one year later. There was no consistent relationship between diversity and stability of biomass production of these plant communities| and species functional identity was the most effective explanation for the observed shifts in biomass production. The presence of C4 species resulted in an increased stability of productivity after extreme climatic events| but resulted in greater overall. shifts in community composition. The presence of C4 species may buffer grassland community productivity against an increased frequency of extreme heating events associated with future global climate change. 5162,2000,2,3,Severe summer rainfall in China associated with enhanced global warming,Trends of extreme wet and dry conditions during recent decades-were examined using observed data for eastern China. Mean precipitation for the region has shown a significant downward trend from the 1950s to the mid-1970s| and a positive trend since the late 1970s. The change in trend since the late 1970s| i.e. the period during which enhanced global warming emerged| is most prominent. The linear trend of the mean summer rainfall anomalies over the 4 subregions studied was +7.5 % decade(-1). Changes in the trend of severe wet and dry events are not symmetrical. During the period 1977-1998| the number of severe wet stations increased at the rate of 20.3 decade(-1)| but the trend far severe dry events was only -5.4 decade(-1). Similar rainfall changes can be found over many global land areas. The summer rainfall in eastern China showed only a negligible secular trend during the period 1880-1998. However| the decadal variations were clear. The mean rainfall in 1990-1998 was higher than for any other decade in the last 100 yr. The linear trend of the 33-station mean during 1977-1998 was +47.5 mm decade(-1); such a strong increase is unprecedented in the record since 1880. Decadal variations and global warming may both play important roles in the recent significant increase in summer rainfall. This paper also presents the results of greenhouse and/or aerosol forcing experiments| in which summer precipitation over eastern China is generally estimated to rise. There are many uncertainties| however| in the regional precipitation simulations. For example| the modeled rainfall is sensitive to whether aerosols are included or not. Further research is needed to determine whether there is a substantial relationship between the rainfall changes in China and global greenhouse warming. 5301,2000,2,3,Simulated responses of potential vegetation to doubled-CO2 climate change and feedbacks on near-surface temperature,Increases in the atmospheric concentration of carbon dioxide and associated changes in climate may exert large impacts on plant physiology and the density of vegetation cover. These may in turn provide feedbacks on climate through a modification of surface-atmosphere fluxes of energy and moisture. This paper uses asynchronously coupled models of global vegetation and climate to examine the responses of potential vegetation to different aspects of a doubled-CO2 environmental change| and compares the feedbacks on near-surface temperature arising from physiological and structural components of the vegetation response. Stomatal conductance reduces in response to the higher CO2 concentration| but rising temperatures and a redistribution of precipitation also exert significant impacts on this property as well as leading to major changes in potential vegetation structure. Overall| physiological responses act to enhance the warming near the surface| but in many areas this is offset by increases in leaf area resulting from greater precipitation and higher temperatures. Interactions with seasonal snow cover result in a positive feedback on winter warming in the boreal forest regions. 3081,2000,2,4,Simulation of climate-change effects on riparian vegetation in the Pere Marquette River| Michigan,Global climate-change models (GCMs) predict that the midwest USA will be drier and warmer as a result of global climate change. Other studies suggest that climate change has already started in the Lake Michigan region. This study uses climate predictions from GCMs and projections of historical climate-change trends to examine the potential effects of climate change on riparian vegetation along the Pere Marquette River in west central Michigan. A model of stream discharge as a function of temperature and precipitation was used to estimate the percent of time that each of 25 plots would be inundated at a field site in the riparian corridor on the river. Four vegetation classes were identified at the field site (Alnus| Open-Viburnum| Fraxinus-Carpinus| and Acer-Tsuga). The stream discharge model was used to calculate the percent of time each plot was inundated at the field site under the different climate scenarios and to predict the distribution of vegetation classes that would be present under climate-change conditions. The results suggest that the areal extent of vegetation classes at the field site may change by up to 27%. 5297,2000,2,3,Simulation of early 20th century global warming,The observed global warming of the past century occurred primarily in two distinct 20-year periods| from 1925 to 1944 and from 1978 to the present. Although the Latter warming is often attributed to a human-induced increase of greenhouse gases| causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) forcing. Results from a set of six integrations of a coupled ocean-atmosphere climate model suggest that the warming of the early 20th century could have resulted from a combination of human-induced radiative forcing and an unusually Large realization of internal multidecadal variability of the coupled ocean-atmosphere system. This conclusion is dependent on the model's climate sensitivity| internal variability| and the specification of the time-varying human-induced radiative forcing. 5342,2000,4,4,Soil-atmosphere exchange of radiatively and chemically active gases,Exchanges between the soils and the atmosphere may control or significantly affect the global budgets of many environmentally important trace gases| both natural and man-made. Flux measurements| taken in several ecosystems| show that soils are a substantial source of chloroform (8 +/- 4 mu g/m(2)/d) and a sink for methyl chloride (-10(-3)(+6) mu g/m(2)/d). The known sources and sinks of these gases are insufficient to explain the observed concentrations. Our findings will help to balance the global budget of chloroform but may put the budget of methyl chloride further out of balance. We also found| consistent with previous research| that soils are a substantial source of nitrous oxide and carbon monoxide and take up hydrogen and methane. The uptake of man-made chlorocarbons was observed| but the rates are small. Observed fluxes of non-methane hydrocarbons showed few patterns except that soils may be a source of ethane and butane. 3145,2000,3,3,Soils and global climate change: Challenges and opportunities,In the interplay of the soil and the atmosphere| the soil can be both a contributor to and a recipient of the impacts of climate change. In the past| land management has generally resulted in considerable depletion of soil organic matter and the release into the atmosphere of such radiatively active gases as carbon dioxide| methane| and nitrous oxide. Global climate change| to the extent that it occurs| will strongly impact all soil processes. At this time| the task of soil management should be to restore soil organic carbon in order to enhance soil structure and fertility and to help counter the atmospheric greenhouse effect| Widely varying estimates of the soil's organic carbon content and of the potential for soil carbon sequestration point to the need to conduct a comprehensive inventory of this important property. 5157,2000,4,4,Solar cycle lengths and climate: A reference revisited,An article published by Friis-Christensen and Lassen [1991] appeared to indicate an association between solar cycle lengths (SCLs) and climate. It attracted worldwide attention and has since been extensively referred to. We here present an updated analysis using a recent temperature reconstruction with the time period of comparison considerably expanded. The correlation is found to be weak. In the light of this new result we analyze the question how the article by Friis-Christensen and Lassen was able to create the impression of a 'strikingly good agreement'| as the authors described it. We show that the main reason is an unacceptable mixing of filtered and nonfiltered data in the graphical representation. Hereby| an artificial agreement of the solar data with the global warming since 1970 was established. The article by Friis-Christensen and Lassen has created and still creates confusion both in scientific and public discussions on climate change. We have therefore found it relevant to deliver the present analysis. 5209,2000,2,4,Solar forcing of the Northern hemisphere land air temperature: New data,It has previously been demonstrated that the mean land air temperature of the Northern hemisphere could adequately be associated with a long-term variation of solar activity as given by the length of the approximately 11-year solar cycle. Adding new temperature data for the 1990s and expected values for the next sunspot extrema we test whether the solar cycle length model is still adequate. We find that the residuals are now inconsistent with the pure solar model. We conclude that since around 1990 the type of Solar forcing that is described by the solar cycle length model no longer dominates the long-term variation of the Northern hemisphere land air temperature. (C) 2000 Elsevier Science Ltd. All rights reserved. 3092,2000,5,4,Solar irradiance during the last 1200 years based on cosmogenic nuclides,Based on a quantitative study of the common fluctuations of C-14 and Be-10 production rates| we have derived a time series of the solar magnetic variability over the last 1200 years. This record is converted into irradiance variations by linear scaling based on previous studies of sun-like stars and of the sun's behavior over the last few centuries. The new solar irradiance record exhibits low values during the well-known solar minima centered at about 1900| 1810 (Dalton) and 1690 AD (Maunder). Further back in time| a rather long period between 1450 and 1750 AD is characterized by low irradiance values. A shorter period is centered at about 1200 AD| with irradiance slightly higher or similar to present day values. It is tempting to correlate these periods with the so-called "little ice age" and "medieval warm period"| respectively. An accurate quantification of the climatic impact of this new irradiance record requires the use of coupled atmosphere-ocean general circulation models (GCMs). Nevertheless| our record is already compatible with a global cooling of about 0.5 1 degrees C during the "little ice age"| and with a general cooling trend during the past millenium followed by global warming during the 20th century (Mann et al.| 1999). 5164,2000,4,4,Solar variability and the search for corresponding climate signals,Instrumental and paleodata from the last centuries are investigated to get circumstantial evidence for external influences on the Earth's climate machine. Such influences could be of extraterrestrial and/or anthropogenic origin. Anthropogenic influences are separated from solar on superdecadal time scales and on a hemispheric level using a non-linear regression model. The function to be explained is the northern hemispheric temperature. The model contains two forcing components explicitly: A parameterized anthropogenic component| which describes the aggregated effect of greenhouse gases| aerosols and other anthropogenic climate impacts. A solar component| which describes the solar variability history. The solution of the regression model allows| under certain assumptions| a functional separation of the variability components and provides an estimation of their relative contributions to global warming during the last 140 years. 5265,2000,4,4,Some agrometeorological aspects of pest and disease management for the 21st century,In the 21st century increasing societal| environmental| and economic pressures will create a changing context for solving agricultural pest management problems. Interdisciplinary approaches to problem solving will be needed to meet goals such as mitigating environmental degradation associated with the use of farm chemicals| and increasing productivity by reducing insect and disease damage to crops| and reducing competition from weeds. Crop system models will provide useful frameworks in which to examine the interrelationships among plants| the pest complex| and the environment to determine the most appropriate management strategies to meet individual and societal goals. Improved techniques for managing pests| such as transgenic plants resistant to pests and diseases| new biological control agents| innovative cultural controls| biological pesticides| and additional information to improve efficacy of traditional chemicals| will require weather data and forecasts in order to be used| and climate information to determine their suitability for use. Climatic change| including global warming and increased variability| will require improved analyses that can be used to assess risks associated with existing and newly developed pest management strategies and techniques| and to gauge the impact of these techniques on productivity and profitability. Control recommendations will need to be evaluated for suitability in the farming system where they are to be implemented. Training in the basics of agrometeorological relationships and pest management disciplines will have to be supplied to agricultural meteorologists| extension personnel involved in this work| and farmers. Research to successfully develop the new technologies and the weather and climatic information required by the technologies must be approached by interdisciplinary teams that include agricultural meteorologists. (C) 2000 Elsevier Science B.V. All rights reserved. 3091,2000,2,4,Some aspects of ecological modeling developments in China,The achievements of the applications of ecological modeling to population dynamics| evolutionary and behaviour ecology| global climate change| ecotoxicology| conservation of biodiversity| sustainable use of biological resources and ecological engineering| and space analysis of ecological data are reviewed. After undergoing three evolution stages in China| some new methods and ideas for ecological modeling have been proposed. It will be a trend that quantitative in combination with qualitative methods are used in future. (C) 2000 Elsevier Science B.V. All rights reserved. 5181,2000,2,4,Stabilization of vaccines: to be or not to be,Thermal lability of live vaccines has been a matter of serious concern right through the early 1960s. Initially| poliovirus stabilization was achieved experimentally by addition of magnesium chloride. Later efforts to stabilize labile biological substances included addition of trehalose| pirodavir| deuterium oxide or compounds based on electrostatic interventions. While addition of deuterium oxide resulted in a significantly stable live poliovirus vaccine| the product development activity was discontinued during the late 1990s [3]. Presently| the scientific community would appear to be casual and lackadaisical about stabilization of vaccines. Several reports on poor performance of biological substances and the climate change justify vigorous efforts towards stabilization of every vaccine| conventional or genetically produced.
5335,2000,3,3,Stimulation by ammonium-based fertilizers of methane oxidation in soil around rice roots,Methane is involved in a number of chemical and physical processes in the Earths atmosphere| including global warming(1)| Atmospheric methane originates mainly from biogenic sources| such as rice paddies and natural wetlands; the former account for at least 30% of the global annual emission of methane to the atmosphere(2). As an increase of rice production by 60% is the most appropriate way to sustain the estimated increase of the human population during the next three decades(3)| intensified global fertilizer application will be necessary(3): but it is known that an increase of the commonly used ammonium-based fertilizers can enhance methane emission from rice agriculture. Approximately 10-30% of the methane produced by methanogens in rice paddies is consumed by methane-oxidizing bacteria associated with the roots of rice(4|5); these bacteria are generally thought to be inhibited by ammonium-based fertilizers| as tvas demonstrated for soils(6-8) and sediments(9|10). In contrast| we show here that the activity and growth of such bacteria in the root zone of rice plants are stimulated after fertilization. Using a combination of radioactive fingerprinting(11) and molecular biology(12) techniques| we identify the bacteria responsible for this effect. We expect that our results will make necessary a re-evaluation of the link between fertilizer use and methane emissions| with effects on global warming studies. 5378,2000,3,4,Strength of CO2 hydrate membrane in sea water at 40 MPa,The strength of the CO2 hydrate membrane that forms at the interface between liquid CO2 and artificial sea water at 40-45 MPa was measured with Du-Nouy type surface tension meter. At low temperatures with a subcooling greater than 5 K| the membrane strength| initially abut 0.1 N/m| decreased with increasing temperature| However| it increased sharply and reached a peak of about 0.9 N/m just below the dissociation temperature and abruptly drops to zero at the dissociation temperature. This abnormal tendency of the membrane strength was previously observed by the authors in an experiment with fresh water. The temperature of the abnormality| however| shifts to lower temperatures and the peak decreases with increasing salinity| This new phenomenon could exert major influences on the various CO2 ocean sequestration methods that have been proposed to mitigate global warming. It can be explained in terms of a model in which the dissociation process of hydrate that occurs near the dissociation temperature enhances the diffusion of water molecules in the hydrate membrane and makes the membrane thicker. 5321,2000,4,4,Structures in tessera terrain| Venus: Issues and answers,Many workers assume that tessera terrain| marked by multiple tectonic lineaments and exposed in crustal plateaus| comprises a global onionskin on Venus. Because tesserae are exposed mostly within crustal plateaus| which exhibit thickened crust| issues of tessera distribution and the mechanism of crustal plateau formation (e.g.| mantle downwelling or upwelling) are intimately related. A review of Magellan data indicates that tessera terrain does not form a global onionskin on Venus| although ribbon-bearing tesserae reflect an ancient time of a globally thin lithosphere. Individual tracts of ribbon-bearing tessera terrain formed diachronously| punctuating time and space as individual deep mantle plumes imparted a distinctive rheological and structural signature on ancient thin crust across spatially discrete 1600-2500 km diameter regions above hot mantle plumes. Plume-related magmatic accretion led to crustal thickening at these locations| resulting in crustal plateaus. Crustal plateau surfaces record widespread early extension (ribbon structures) and local| minor perpendicular contraction of a thin| competent layer above a ductile substrate. Within individual evolving crustal plateaus the thickness of the competent layer increased with time| and broad| gentle folds formed along plateau margins and short| variably oriented folds formed in the interior; late complex graben cut folds. Local lava flows accompanied all stages of surface deformation. In contrast to these conclusions| Gilmore er nl. [1998] summarized post-Magellan arguments in favor of downwelling models for crustal plateau formation. In light of this discrepancy| we reexamine the regions investigated by these workers and evaluate their arguments against upwelling| models. We show that Gilmore et al. [1998] did not differentiate ribbons from graben and therefore their proposed temporal relations are invalid; they disregarded shear fracture ribbons| thus invalidating their criticism of ribbon models; they misunderstood previous radargrammetric work that constrains ribbon geometry; and they relied solely on geometrical relations to constrain timing| violating kinematic analysis methodology. Their stratigraphic constraints on ribbon-fold temporal relations are invalid because they (1) misinterpreted implications of map relations; (2) did not isolate radar artifacts due to local radar slope effects from proposed material units; (3) chose a region for analysis that clearly shows the effects of younger tectonism and volcanism; and (4) presented map relations that cannot be reproduced. Their attempts to discount upwelling models of crustal plateau formation fail because they combine fundamentally different pre-Magellan and post-Magellan upwelling models. These misconceptions about the upwelling model and processes responsible for global warming [Phillips and Hansen| 1998]| lead to serious errors in Gilmore et al.'s [1998] criticism. Furthermore| we show that the data of Gilmore et nl. [1998] are actually more consistent with upwelling than downwelling models| consistent with arguments that tessera terrain is not global in spatial distribution. 5355,2000,2,3,Sulfur dioxide emissions in Asia in the period 1985-1997,A consistent set of SO2 emission trends has been developed for Asian countries for the time period 1985-1997. The trend is based on extrapolation of a detailed 1990 inventory| which was constructed as part of the World Bank's RAINS-ASIA project| using IEA energy-use data. The trend shows Asian SO2 emissions growing from 33.7 Tg in 1990 to 39.2 Tg in 1997. Estimates interpolated fr om the RAINS-ASIA computer model suggest a value for 1997 of 46.4 Tg| assuming no major changes in emission abatement policies after 1990. The reduction in the 1997 value| by some 16%| is primarily due to regulatory requirements and other trends toward lower sulfur content of oil products and coal. A slowdown in the growth of emissions in China - due to a reduction in economic growth| the mining of higher-quality coals| enhanced environmental awareness| and a reduction in industrial coal use - has been instrumental in arresting the growth of Asian emissions. Most of the positive developments have occurred in East Asia| and high-emission growth rates persist in Southeast Asia and the Indian subcontinent. The outlook for the future is that Asian SO2 emissions may well peak in the region of 40-45 Tg by the year 2020 or earlier| in contrast to previous predictions of 2020 emissions as high as 80-110 Tg. The trends developed in this paper are good news for the local and regional environment| particularly in East Asia. However| they also signify lower-than-anticipated concentrations of sulfate aerosol over the Asian continent| with the resulting possibility of greater-than-anticipated regional and global warming. (C) 2000 Elsevier Science Ltd. All rights reserved. 5347,2000,3,3,Sulfur hexafluoride (SF6): Global environmental effects and toxic byproduct formation,This work provides information concerning possible global environmental implications and personnel safety aspects that should be considered during the commercial uses of sulfur hexafluoride (SF6). SF6 is an anthropogenically produced compound| mainly used as a gaseous dielectric in gas insulated switchgear power installations. It is a potent greenhouse gas with a high global warming potential| and its concentration in the earth atmosphere is rapidly increasing. During its working cycle| SF6 decomposes under electrical stress| forming toxic byproducts that are a health threat for working personnel in the event of exposure. Several precautions are recommended to avoid personnel exposure to toxic byproducts: oxyfluoride levels or other byproduct concentrations in the operating gas matrix should be traced to predetermine the overall gas toxicity; contaminants should be systematically considered during maintenance| chamber evacuation and system opening process; small SF6 quantities leaking into air or stagnated pollutant concentrations in the operating field should be analyzed and compared to the threshold limit values and permissible exposure levels. New system design rules (i.e.| hermetically sealed gas compartments| gas recycling or disposal in the field area) and different handling policies-both during maintenance and final disposal-now should be considered globally to provide for environmental and personnel safety.
5248,2000,4,3,Surficial processes and CO2 flux in soil ecosystem,Global warming as a result of rising levels of atmospheric CO2 concentration has become an issue of increasing environmental concerns. This study is to estimate the role of surficial processes| including solar radiation| air temperature| relative humidity| rainfall| soil water movement and heat flux| and soil respiration| on CO2 diffusive flux into the atmosphere from a soil ecosystem. An existing one-dimensional mathematical model for the simultaneous movement and transport of water| heat| and CO2 through the unsaturated soil is modified for the purpose of this study. Two simulation scenarios (i.e. daily and monthly) are performed to estimate the CO2 flux through the soil ecosystem. Simulation results show that surficial processes have decisive effects on CO2 flux through the soil ecosystem. Of the processes examined in this study| solar radiation is one of the most important processes. It governs the daily cycles of soil temperature and water evaporation| which in turn controls the soil CO2 production rates| and thereby the CO2 flux into the atmosphere. Rainfall is another important process that controls the monthly CO2 flux. It determines the soil water content available for biological respiration and the air-filled pore spaces available for CO2 flux. Daily cycles of the soil CO2 production rate are similar to those of the surface temperature| but the overall magnitude decreases consecutively in response to the increase in soil water content. Soil CO2 production rate is controlled by both soil temperature and soil water content. As the soil water content decreases| the overall CO2 production rate is expected to decrease. The pattern of CO2 flux is more or less similar to that of the surface soil temperature (i.e. increasing during the day and decreasing during the night)| but the overall magnitude decreases consecutively over time. The daily variations of surface CO2 flux are driven by soil temperature| whereas the overall increase in CO2 flux rate is due to the increase in CO2 concentration immediately beneath the soil surface. This study suggests that surficial processes play an ultimate role in soil CO2 flux into the atmosphere. (C) 2000 Elsevier Science B.V. All rights reserved. 3123,2000,2,2,Sustainable development| human induced global climate change| and the health of children,In this short article we introduce the concept of sustainable development and its significance to child health using climate change as an example. Environmental issues| in the long term| are as important to children's health as smoking| accidents| and poor parenting are in the short term| yet have hitherto had little publicity or discussion within paediatric circles. What is happening to children's health in the world? In the developed world cardiovascular disease| diabetes| cancer| and dental disease are all on the increase| while in the developing world malnutrition| infectious disease| and injuries are still rife. At present| inequalities of health and wealth—both within and between nations—appear to be increasing|1 with an adverse impact on children's health. The Ottawa charter for health promotion states that the fundamental conditions for health are peace| shelter| education| food| income| a stable ecosystem| sustainable resources| social justice| and equity.2 The evidence for the connections among the environment| the economy| and social change are compelling and any change within one inevitably affects the others.
5204,2000,5,3,Termination of global warmth at the Palaeocene/Eocene boundary through productivity feedback,The onset of the Palaeocene/Eocene thermal maximum (about 55 Myr ago) was marked by global surface temperatures warming by 5-7 degrees C over approximately 30|000 yr (ref. 1)| probably because of enhanced mantle outgassing(2|3) and the pulsed release of similar to 1|500 gigatonnes of methane carbon from decomposing gas-hydrate reservoirs(4-7). The aftermath of this rapid| intense and global warming event may be the best example in the geological record of the response of the Earth to high atmospheric carbon dioxide concentrations and high temperatures. This response has been suggested to include an intensified flux of organic carbon from the ocean surface to the deep ocean and its subsequent burial through biogeochemical feedback mechanisms(8). Here we present firm evidence for this view from two ocean drilling cores| which record the largest accumulation rates of biogenic barium-indicative of export palaeoproductivity-at times of maximum global temperatures and peak excursion values of delta(13)C. The unusually rapid return of delta(13)C to values similar to those before the methane release(7) and the apparent coupling of the accumulation rates of biogenic barium to temperature| suggests that the enhanced deposition of organic matter to the deep sea may have efficiently cooled this greenhouse climate by the rapid removal of excess carbon dioxide from the atmosphere. 3053,2000,3,3,The cost of carbon retention by reduced impact logging,Reduced impact logging (RIL) is one means of reducing the carbon emissions held responsible for global warming. It may also reduce other adverse logging effects. A study of RIL's effects in Sabah| Malaysia| found 44% reduction of area logged within a tract| 22% reduction in timber yield per logged hectare| and 18% increase in cost per m(3) logged compared with conventional logging (CL). Estimated timber yield at the next harvest was 31% higher following RIL. Compared with unlogged forest| RIL damaged rattan| wildlife| soil and water quality values less than did CL. However| RIL's environmental benefits per area of forest logged are considerably compromised by the greater logging area required for st given timber yield. Doing RIL in place of CL had a net cost per unit area at all rates of discount. Per m3 of timber logged| RIL was beneficial without discounting| but had a net cost at a 2% discount rate and higher The overall cost of RIL's superior carbon retention varied with both discount rate and level of analysis| from negative price to more than US$ 50 per megagram at a 10% discount rate. RIL appears most cost-effective on a per m3 logged basis at low discount rates. However| at commonly applied discount rates (4% and above) RIL's carbon price exceeds most published estimates for carbon prices. (C) 2000 Elsevier Science B.V. All rights reserved. 3068,2000,4,4,The decline of forest productivity as stands age: a model-based method for analysing causes for the decline,For closed canopy forests| both above-ground net primary productivity (ANPP) and wood yield decline as stands age. However the physiological mechanisms responsible for the decline are not well understood. Understanding of the causes of the decline and incorporation of aging mechanisms into models of forest production are essential both for sound forest management and for reliable prediction of changes in terrestrial carbon storage under altered climates. To investigate causes for declining net primary productivity (NPP) an ecosystem model G'DAY was modified to include aging mechanisms associated with three main current hypotheses for NPP decline. These hypotheses are: (1) sapwood maintenance respiration increases as stands age| reducing the availability of carbon to support growth; (2) stomatal conductance and hence photosynthetic rates decline; and (3) soil nitrogen availability declines due to nitrogen (N) accumulation in woody litter. A model-based method was developed for determining the relative importance of three mechanisms for NPP decline in forest stands. The method involves a decomposition of simulated model output into three components| each related to one aging mechanism. The method is illustrated by parameterizing G'DAY for young (40 year-old) and mature (245 year-old) stands of Pinus contorta in Colorado USA. Results from this method of analysis indicate that: 1. The G'DAY model without aging mechanisms cannot reproduce the observed changes in NPP as stands age. When the above three aging mechanisms are switched off| G'DAY shows only transient changes in NPP lasting less than 20 years. When the aging mechanisms are incorporated in G'DAY| the model simulates declining NPP on a scale similar to that observed in the field. 2. The gradual decline in NPP following canopy closure is sensitive to assumptions about aging mechanisms and is particularly sensitive to assumptions about soil N availability and declining photosynthetic rates. We identified key areas of model uncertainty requiring further experimental clarification. Here we highlight two inadequately understood processes: soil N immobilization associated with woody litter accumulation and changes in carbon allocation as stands develop. (C) 2000 Elsevier Science B.V. All rights reserved. 5171,2000,2,3,The economics of the greenhouse effect: evaluating the climate change impact due to the transport sector in Italy,The transport sector significantly contributes to energy consumption and carbon dioxide emissions| accounting for about one-third of the total carbon dioxide emissions in OECD countries. In this paper the issues of energy consumption and carbon dioxide emissions in the transport sector in Italy are addressed. A comparative static approach is applied for the years 1980 and 1995. A decomposition scheme is proposed in order to highlight the main factors determining the variation of carbon dioxide emissions over the period. Then| an evaluation of the impact of the transport sector in terms of global warming is attempted| using some monetary estimates. Results indicate that the main driving force of the variation of carbon dioxide emissions in Italy is the growth in GDP. Total global warming damage caused by the transport sector in Italy ranges from 0.02 to 0.1% of GDP. (C) 2000 Elsevier Science Ltd. All rights reserved. 3070,2000,2,3,The effect of global climate change on the regions of tropical convection in CSM1,The impact of enhanced carbon dioxide concentrations on deep tropical convection (DTC) is explored using the National Center for Atmospheric Research (NCAR) Climate System Model (CSM 1) model. A 134-year simulation in which CO concentrations increase 1 % year(-l) is analyzed. With approximately present-day CO2 concentrations (367 ppmv) the CSM1 simulation captures the observed relationship between outgoing longwave radiation (OLR) and sea-surface temperature (SST) in the tropics. The temperature threshold for deep convection in the model is approximately 24.75 degrees C. As CO2 concentrations increase| the simulated threshold temperature for tropical convection progressively increases to similar to 25.55 degrees C and 26.55 degrees C at 2xCO(2) (year 80) and 3.4xC0(2) (year 133). The fully coupled climate model response to increased CO2 concentrations implies that the expansion of the 26 degrees C isotherm| the present-day observed threshold| wilt not yield an expansion of the regions of DTC. 5345,2000,2,4,The effect of ration on acclimation to environmental acidity in rainbow trout,Freshwater salmonids exposed to low environmental pH typically suffer a net loss of ions| primarily Na+ and Cl-| across the gills| resulting in reduced plasma and tissue ion concentrations. However| in recent experiments in our laboratory| juvenile rainbow trout| Oncorhynchus mykiss| fed a ration of 1% body weight d(-1) or greater showed no ionoregulatory disturbance during chronic| sublethal acidification. This raised the possibility that these fish had acclimated to low pH in that they would be better able to withstand further| more severe acidification than fish that had no prior experience of acid conditions: previous studies had concluded that such acclimation does not occur. This hypothesis was tested by measuring unidirectional ion fluxes during a 24 h acute acid challenge (pH 4.2) in juvenile rainbow trout that had previously been exposed to either ambient pH 6.2 (naive fish) or sublethal low pH 5.2 (acid pre-exposed fish) for 90 days| and fed a ration of either 1.0 or 0.25% d(-1) (wet basis). No mortalities were observed during the acute acid challenge in the fish fed the higher ration and no differences between the two groups in the response of Na+ fluxes were observed. Sodium influx in both groups was significantly inhibited throughout the challenge and Na+ net flux was significantly stimulated over the first 6 h. Prior to the acute acid challenge| the fish fed the lower ration that had previously been exposed to pH 5.2 had significantly lower plasma ion concentrations than those fish previously exposed to pH 6.2. Both groups suffered mortalities; those of the naive fish (22% by 24 h) being markedly lower than those of the acid pre-exposed fish (68% by 24 h). However| there were no significant differences in either Na+ or Cl- fluxes between the two groups of fish during the acid challenge: both showed significant inhibition of ion influxes and significantly greater net ion losses| resulting in reduced plasma ion concentrations. These results indicate that rainbow trout are unable to acclimate to environmental acidification irrespective of the availability of dietary salts. 5169,2000,2,4,The effects of subgrid-scale parameterizations in a zonally averaged ocean model,Isopycnal diffusion and an additional transport velocity parameterizing the effect of mesoscale eddies are implemented in the ocean component of a 2.5-dimensional zonally averaged coupled ocean-atmosphere model. The equilibrium states of the coupled ocean-atmosphere model| resulting from the different mixing parameterizations| are compared| and extensive parameter sensitivity studies are presented. For the equilibrium base states| the new mixing schemes result in changes in the distributions of temperature and salinity that are significant in the Southern Ocean| where the isopycnal surfaces are steep and the eddy-induced transport velocity approximately cancels the Deacon cell. The temperature and salinity changes are relatively small in the rest of the ocean. Furthermore| the implementation of the new mixing schemes results in significant changes in the strength and the pattern of the thermohaline circulation. Transient responses of the coupled ocean-atmosphere system in global warming scenarios are compared for the different mixing parameterizations. It is demonstrated that large changes in the stability of the thermohaline circulation occur and that the observed changes in stability are highly parameter dependent. 5177,2000,3,3,The future of nuclear energy in Europe,7Are concerns about global warming of the Earth's atmosphere going to rekindle interest in nuclear power and in building new nuclear power plants in Europe? As a consequence of the discussions about the climate| the use of nuclear power as an important energy source is currently being re-evaluated| finds Dr. Wolf-J. Schmidt-Kiister| Secretary General of FORATOM| the European Atomic Forum| headquartered in Brussels. In his article| he argues that a renaissance of nuclear power will be possible also in Europe once politics supports resuming an unbiased discussion of all topics associated with the energy problem. Europe must face two problems in the energy sector for which solutions must be found: the growing dependence on fossil energy resources| and the need to curb greenhouse gas emissions| especially those of carbon dioxide. Nuclear power is already making a sizable contribution towards the solution of these problems| but its future potential has hardly been tapped. Public acceptance of nuclear power shows that the intention to opt out of the peaceful uses of nuclear power is not based on an identical attitude of the public| but is motivated politically| finding only little public support| as in the cases of Sweden and Germany. 5352,2000,4,4,The generation of CO2 in sewage sludge treatment systems: life cycle assessment,Life cycle assessment (LCA) on total sewage sludge treatment systems including thickening. anaerobic digestion| dewatering| and incineration/melting was performed to estimate a global warming impact as carbon dioxide (CO2) emission. As representative processes for the assessment| the most typical and widely used processes were selected. Generally. the life cycle of actual treatment facilities consists of three stages: construction. operation and dismantlement. In this study| the amount of CO2 produced from the life cycle steps of existing unit sludge treatment processes| was calculated by inventory analysis of input materials. In addition| for all processes investigated| individual CO2 emission units (CEUs)| i.e. the amount of emitted CO2 for treating a unit weight of sludge| were also calculated. By using the obtained CEU matrix| it was possible to simulate the CO2 production from various types of complex treatment systems as well as to trace the dominant cause of CO2 production in individual treatment processes. 3075,2000,2,4,The global spread of malaria in a future| warmer world,The frequent warnings that global climate change will allow falciparum malaria to spread into northern Latitudes| including Europe and Large parts of the United States| are based on biological transmission models driven principally by temperature. These models were assessed for their value in predicting present| and therefore future| malaria distribution. In an alternative statistical approach| the recorded present-day global distribution of falciparum malaria was used to establish the current multivariate climatic constraints. These results were applied to future climate scenarios to predict future distributions| which showed remarkably few changes| even under the most extreme scenarios. 5182,2000,4,4,The heat sources and sinks of the 1986-87 El Nino,The heat balance of the coupled tropical ocean-atmosphere system during the Earth Radiation Budget Experiment (ERBE) period (1985-89) is analyzed in an attempt to better understand the heat sources and sinks of the 1986-87 El Nino. The analysis involves the use of radiation data from ERBE| circulation statistics from National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis| and the assimilated data for the Pacific ocean. Accumulation of heat in the equatorial upper ocean is found prior to the onset of the 1986-87 El Nino. The accumulated heat in the equatorial upper ocean comes from the surface heating| which exceeds the poleward transport of heat in the upper ocean. The accumulated heat in the upper ocean resurfaces in the eastern Pacific and the 1986-87 El Nino warming develops. The warming results in a substantial increase in the equator-to-pole heat transport in the equatorial ocean. The ocean warming is also accompanied by a significant increase in the poleward transport of energy in the atmosphere and a significant reduction in the surface heat Aux into the equatorial ocean| though these changes are smaller than the increases in the poleward heat transport in the ocean. Because of the feedbacks from water vapor and clouds| the variations in the net radiative energy flux at the top of the atmosphere are small and the surface heat flux into the equatorial ocean is mainly modulated by the poleward transport of energy in the atmosphere| which is in turn modulated by the intensity of the cold tongue. The anomalous poleward ocean heat transport does not stop right at the time when the surface warming is terminated| and this "overshooting" pushes the equatorial ocean to a cold state-the 1988-89 La Nina-during which the poleward transport in the atmosphere and ocean is reduced and heat starts to accumulate in the upper ocean again. The coupled system is then in a situation similar to 1985 and is preparing for the onset of another El Nino. The results suggest that ENSO system behaves like a heat pump: the equatorial ocean absorbs heat during the cold phase and pushes the heat to the subtropical ocean during the warm phase. This picture for El Nino implies that the surface heat flux into the equatorial ocean may be a driving force of El Nino. The relationship between this picture for El Nino and the delayed oscillator hypothesis is explored. An explanation for the absence of El Nino in the tropical Atlantic ocean is offered by noting that the zonal width of the basin limits the amount of heat that can be accumulated in the upper ocean. The implication of the present findings for the response of El Nino to global warming is discussed. 5232,2000,4,5,The influence of cosmic terrestrial clouds and global warming,We analyse the new ISCCP (International Satellite Cloud Climatology Project) D2 cloud data to ascertain whether or not a connection between cosmic ray flux and cloud cover exists. Despite a previous finding that total cloud factor and cosmic ray fluxes were correlated| our results indicate that only the low-level cloud follows solar activity over the full period| 1983-1994. Using several proxies for solar activity and the radiative forcing calculated by Ockert-Bell (1992) for the ISCCP cloud types| we estimate the possible impact that such a solar-terrestrial connection may have on climate. We conclude that| possibly excluding the most recent decades| much of the warming of the past century can be quantitatively accounted for by the direct and indirect effects of solar activity.
5168,2000,3,4,The Kyoto protocol and payments for tropical forest: An interdisciplinary method for estimating carbon-offset supply and increasing the feasibility of a carbon market under the CDM,Protecting tropical forests under the Clean Development Mechanism (CDM) could reduce the cost of emissions limitations set in Kyoto. However| while society must soon decide whether or not to use tropical forest-based offsets| evidence regarding tropical carbon sinks is sparse. This paper presents a general method for constructing an integrated model (based on detailed historical| remote sensing and field data) that can produce land-use and carbon baselines| predict carbon sequestration supply to a carbon-offsets market and also help to evaluate optimal market rules. Creating such integrated models requires close collaboration between social and natural scientists. Our project combines varied disciplinary expertise (in economics| ecology and geography) with local knowledge in order to create high-quality| empirically grounded| integrated models for Costa Rica. (C) 2000 Elsevier Science B.V. Ail rights reserved. 5288,2000,2,4,The large carbon emission from terrestrial ecosystems in 1998: A model simulation,The relationship between the carbon balance of terrestrial ecosystems and climate anomalies in 1998| the warmest year since 1860| was investigated by means of a mechanistic global biosphere model (Sim-CYCLE) based on the plant-production theory. We simulated the monthly time-series and spatial distribution of atmosphere-biosphere CO2 exchange from 1961 to 1998| based on the Sim-CYCLE by inputting the NCEP/NCAR-reanalysis climate data at the spatial resolution of T62 (containing 5828 land pixels after the Matthews biome map). The peculiar climate conditions in 1998| i.e.| strong ENSO event and global warming (+0.58 degrees C above the long-term mean)| resulted in a remarkable anomaly (as much as 2.7 Pg C yr(-1) of net emission) via the accelerated plant respiration and soil decomposition. The strong sources were in eastern Siberia| northern South America| and South Africa. This anomaly| equivalent to +1.26 ppmv yr(-1) of an increase rate of atmospheric CO2 concentration| can be a major cause of the extraordinarily high CO2 increase rate in 1998. 5329,2000,3,3,The National Academy of Sciences offers a new framework for addressing global warming issues,The recent landmark report by the National Academy of Sciences reviewed the science on which the Kyoto Protocol was based. NAS concluded that the policy choices and the mandatory reductions in greenhouse gases by the developed nations were based on incomplete science with significant uncertainties. In view of these uncertainties the NAS report developed a comprehensive strategic 10-year research program to address the basic issue of whether human activity that results in environmental changes is responsible for climate changes. The report provides a new framework for consideration of global warming issues. The UN International Panel on Climate Change (the UN science advisor) in its 1997 report to the Kyoto parties pointed out the confusing difference between scientific usage of the term "climate change" that distinguishes human from natural causes of change and the official usage that combines natural and human causes of changes in climate. The conclusion of the UN panel on human causes is equivocal. The 1999 report of the U.S. Global Science Research Committee also reached an equivocal conclusion on human causes and announced a 10-year research program to be developed in consultation with NAS| The precautionary measures provided in the 1992 UN Framework Convention differ from the ill defined "precautionary principle" based on fear of uncertainty| and are consistent with the objectives of the NAS proposed research program|These developments together with the third report of the UN Intergovernmental Science Panel on developments in climate science due in 2001 merit consideration by the convention of the parties under the Kyoto Protocol. (C) 2000 Academic Press. 3118,2000,2,4,The potential impacts of global climate change on spring-maize growth in Shenyang,Physiological ecology simulation modelling of maize growth (MPESM) was used to simulate the variation of soil moisture| maize development and maize growth under twelve prescribed climate scenarios| which include doubling CO2| raising mean temperature by 1.5 degrees C| 3.0 degrees C and 4.5 degrees C| and changing precipitation by 0| + 20%| - 20%| and - 40%. The simulated results were compared with that of the present climate| to assess the sensitivity of maize to climatic change. The analysis indicated that soil moisture is sensitive to reduced precipitation| maize development is sensitive to the rise of temperature| and maize growth is affected greatly by temperature elevation and precipitation variation| which cancel out the positive effects of CO2 elevation. It was found that with the severe change of climate| the leaf biomass| the female fringe biomass| and the leaf area index would decline greatly| and the biomass of stem and root would increase greatly. The average yield of maize will decline between 5% and 30%. 5311,2000,4,2,The record breaking global temperatures of 1997 and 1998: Evidence for an increase in the rate of global warming?,During the time between May of 1997 and September of 1998| for sixteen consecutive months| each month broke the previous monthly all-rime record high temperature. Using autoregressive intervention moving average (ARMA) models in a series of Monte Carlo experiments the probability of such an event was analyzed for various rates of temperature change. The string of record-breaking global temperatures could not be readily explained by the best fit linear increase of temperature since the late 1970's (2 degrees C/Century)| although the event was not implausible (probabilities slightly less than 5%). The 1997-98 event could signal yet another change point in the rate of global temperature increase| but the warming rate over the past few decades is already comparable to that projected during the 21st Century based on IPCC business as usual scenarios of anthropogenic climate change (Kattenberg ct al.| 1996). 5369,2000,4,4,The response of climatic jump in summer in North China to global warming,To reveal climatic variation over North China| the climatic jump in summer in Beijing are analyzed using the data of precipitation of summer (June. July| August) during the period of 1841-1993| in which those missed before 1950 were reconstructed by the stepwise regression method with minimum forecast error. The climatic jumps at different scales are analyzed using different diagnostic methods with different decade (10-100 years) windows. Some new methods and ideas are proposed. The variance difference. the linear tendency difference| and the difference of power spectral distribution between the samples before and after the period at the moving point in the center of the series are compared with other methods (fbr example| Mann-Kendall test| t-test| and accumulative anomaly etc.). Considering the differences among the statistics above| a synthetic jump index is also proposed in order to get the definite jump points in the moving series. The results show that the climatic jumps in the area occurred in the 1890s. the 1910s and the 1920s| and mostly in the 1920s| which suggests that the local climatic: jumps in North China have I simultaneous response to the global warming in the hundred-year scales. 3129,2000,2,4,The role of the Southern Ocean in uptake and storage of anthropogenic carbon dioxide,An ocean-climate model that shows high fluxes of anthropogenic carbon dioxide into the Southern Ocean| but very Low storage of anthropogenic carbon there| agrees with observation-based estimates of ocean storage of anthropogenic carbon dioxide. This low simulated storage indicates a subordinate role for deep convection in the present-day Southern Ocean. The primary mechanism transporting anthropogenic carbon out of the Southern Ocean is isopycnal transport. These results imply that if global climate change reduces the density of surface waters in the Southern Ocean| isopycnal surfaces that now outcrop may become isolated from the atmosphere| tending to diminish Southern Ocean carbon uptake. 5363,2000,4,3,The role of the sun in climate forcing,The Sun is by far the most important driving force of the climate system. However| only little is known how variable this force is acting on different time scales ranging from minutes to millennia and how the climate system reacts to changes in this forcing. Changes of the global insolation can be related to the nuclear fusion in the core of the Sun| the energy transport through the radiative zone and the convection zone| the emission of radiation from the photosphere| and the distance between Sun and Earth. Satellite based measurements over two decades show a clear correlation between the solar irradiance and the Ii-year sunspot cycle. The irradiance amplitude is about 0.1%. This is too small to affect significantly the climate. However| there are indications that| on longer time scales| solar variability coluld be much larger. The analysis of cosmogenic nuclides stored in natural archives provides a means to extend our knowledge of solar variability over much longer time periods. The response of the climate system to solar forcing depends not only on the amount of radiation| but also on its spectral composition (e.g. UV contribution)| seasonal distribution over the globe| and feedback mechanisms connected with clouds| water vapour| ice cover| atmospheric and oceanic transport and other terrestrial processes. It is therefore difficult to establish a quantitative relationship between observed climate changes in the past and reconstructed solar variability. However| there is growing evidence that periods of low solar activity (so called minima) coincide with advances of glaciers| changes in lake levels| and sudden changes of climatic conditions. These findings point to an active role of the Sun in past climate changes beside other geophysical factors| internal variability of the climate system| and greenhouse gases. In fact a non-linear regression model to separate natural and anthropogenic forcing since 1850 is consistent with a solar contribution of about 40% to the global warming during the last 140 years. (C) 1999 Elsevier Science Ltd. All rights reserved. 5195,2000,4,3,The seasonal cycle in coupled ocean-atmosphere general circulation models,We examine the seasonal cycle of near-surface air temperature simulated by 17 coupled ocean-atmosphere general circulation models participating in the Coupled Model Intercomparison Project (CMIP). Nine of the models use ad hoc "flux adjustment" at the ocean surface to bring model simulations close to observations of the present-day climate. We group flux-adjusted and non-flux-adjusted models separately and examine the behaviol- of each class. When averaged over all of the flux-adjusted model simulations| near-surface air temperature falls within 2 K of observed values over the oceans. The corresponding average over non-flux-adjusted models shows errors up to similar to6 K in extensive ocean areas. Flux adjustments are not directly applied over land| and near-surface land temperature errors are substantial in the average over flux-adjusted models| which systematically underestimates (by similar to5 K) temperature in areas of elevated terrain. The corresponding average over non-flux-adjusted models forms a similar error pattern (with somewhat increased amplitude) over land. We use the temperature difference between July and January to measure seasonal cycle amplitude. Zonal means of this quantity from the individual flux-adjusted models form a fairly tight cluster (all within similar to 30% of the mean) centered on the observed values. The nonflux-adjusted models perform nearly as well at most latitudes. In Southern Ocean mid-latitudes| however| the non-flux-adjusted models overestimate the magnitude of January-minus-July temperature differences by similar to5 K due to an overestimate of summer (January) near-surface temperature. This error is common to five of the eight non-flux-adjusted models. Also| over Northern Hemisphere mid-latitude land areas| zonal mean differences between July and January temperatures simulated by the non-flux-adjusted models show a greater spread (positive and negative) about observed values than results from the flux-adjusted models. Elsewhere| differences between the two classes of models are less obvious. At no latitude is the zonal mean difference between averages over the two classes of models greater than the standard deviation over models. The ability of coupled GCMs to simulate a reasonable seasonal cycle is a necessary condition for confidence in their prediction of long-term climatic changes (such as global warming)| but it is not a sufficient condition unless the seasonal cycle and long-term changes involve similar climatic processes. To test this possible connection| we compare seasonal cycle amplitude with equilibrium warming under doubled atmospheric carbon dioxide for the models in our data base. A small but positive correlation exists between these two quantities. This result is predicted by a simple conceptual model of the climate system| and it is consistent with other modeling experience| which indicates that the seasonal cycle depends only weakly on climate sensitivity. 5373,2000,2,4,The sustainability of the water industry in a regulated environment,A complex regulatory system now governs the privatised water industry in England and Wales. There is now a key question as to whether this system is adequate to ensure that the government's aim of sustainability can be achieved. Sustainability policies need to be considered in the light of the international| European and national initiatives| and many of these will impact on the water industry in England and Wales. Two areas are highlighted as of particular importance. The first concerns water resources and how water abstraction| leakage and flooding can be controlled alongside the corresponding uncertainty of global warming. Second| the issue of bathing water quality demonstrates problems of financing improvement programmes| and the adequacy of current programmes in ensuring a cleaner bathing water environment for the next generation. The issues have to be considered alongside the mechanisms and procedures for reaching decisions under the present regulatory framework. These decision-making structures will prove central to any robust sustainability for the water industry. 3133,2000,3,3,The urban environment and health in a world of increasing globalization: issues for developing countries,Urban living is the keystone of modern human ecology. Cities have multiplied and expanded rapidly worldwide over the past two centuries. Cities are sources of creativity and technology| and they are the engines for economic growth. However| they are also sources of poverty| inequality| and health hazards from the environment. Urban populations have long been incubators and gateways for infectious diseases. The early industrializing period of unplanned growth and laissez-faire economic activity in cities in industrialized countries has been superseded by the rise of collective management of the urban environment. This occurred in response to environmental blight| increasing literacy| the development of democratic government| and the collective accrual of wealth. In many low-income countries| this process is being slowed by the pressures and priorities of economic globalization. Beyond the traditional risks of diarrhoeal disease and respiratory infections in the urban poor and the adaptation of various vector-borne infections to urbanization| the urban environment poses various physicochemical hazards. These include exposure to lead| air pollution| traffic hazards| and the "urban hear| island" amplification of heatwaves. As the number of urban consumers and their material expectations rise and as the use of fossil fuels increases| cities contribute to the large-scale pressures on the biosphere including climate change. We must develop policies that ameliorate the existing| and usually unequally distributed| urban environmental health hazards and larger-scale environmental problems. 5198,2000,3,4,The use of economic instruments and green taxes to complement an environmental regulatory regime,In 1999| some countries are developing and effectively applying economic instruments for environmental protection and natural resource management| whilst others are relying on command and control regulatory procedures under-enforced by sometimes inadequately trained and motivated enforcement officers. This paper considers the current and future role of economic instruments as policy instruments for use by governments. In many developed countries| past over-regulation allied to a serious shortfall of experienced environmental enforcers required regulatory regimes to be supplemented by well targeted economic instruments and green taxes. Their application to countries which do not have developed environmental control systems is more questionable. The purported threats of the longer term effects of global warming| damage to the ozone layer and an apparent loss of biodiversity have led environmentalists to adopt the so-called precautionary principle. Sustainable development has added to the pressures for further national and transfrontier legislation. The challenge facing policymakers| therefore| is to design policies to enable market forces to operate in the environmental sphere| for example through a system of pollution charges| principally intended to promote greater environmental efficiency. These charging systems can be of many kinds but their main defining feature is their reliance on markets and the price mechanism to internalise environmental externalities| thereby attempting to make polluters pay through facing the full social costs of their activities. Some of the applications of these charging systems| financial and fiscal instruments and tradable emission systems are explained and illustrated. 5382,2000,3,3,The use of LCA for the environmental evaluation of the recycling of galvanised steel,Life Cycle Assessment has been used to compare the environmental performance of landfilling of the zinc used for galvanising steel with recycling by a number processes. Hypothetical process routes were composed involving three different EAF dust treatment processes| Waelz kiln| DC-furnace| and EZINEX| as well as scrap dezincing. The study shows that recycling of zinc used for galvanising steel clearly has environmental benefits in that it saves zinc resources. However| zinc recovery does not necessarily decrease the potential impact on global warming and acidification. The magnitude of these two impact categories is tightly correlated with the amount and type of primary energy consumed in a process. Due to the high electricity consumption in the dezincing process| this route has the highest impact on Global Warming Potential as well as Acidification Potential. The major part of the energy requirement for the production of zinc from primary and secondary sources is consumed in the reduction of ZnO to Zn. The consequence is that the theoretically possible saving in primary energy by recycling zinc-containing materials is relatively small. The impact categories land use and waste generation are not considered in this study| but most likely the evaluation of such impacts would further increase the potential environmental impact of the landfill alternative. The results also show that the location of an electricity-intensive process highly affects the potential environmental impact. Comparing process and material alternatives in LCA studies where branch average data is used is therefore considerably more complex than when ICA is used within a company. 5246,2000,3,4,Thermoacoustic cooling for surface combatants,Thermoacoustic cooling technology uses high amplitude acoustic standing waves in inert gasses to pump heat It requires no toxic| ozone-depleting| or global warming gasses and has few or no moving Parts| no sliding seals and requires no lubrication for robust and very low maintenance operation. Thermoacoustic cooling units have been demonstrated aboard the Space Shuttle in 1992 and aboard the USS Deyo (DD 989) in 1995 to cool radar electronics. Currently| a 3-ton electrically driven unit is being built for shipboard application. This 3-ton unit will enable the ship designer to provide greater combat system survivability through distributed system architecture and reduced manning by unit simplicity and resulting high reliability. Additionally| waste heat cooling is an emerging thermoacoustic technology that could utilize stack gas heat from main gas turbine engines or from gas turbines generators to create shipboard cooling. The benefits of this waste heat cooling is lower infrared (IR) signature and reduced fuel consumption.
5174,2000,3,4,Total costs and benefits of biomass in selected regions of the European Union,The paper describes results of the BioCosts project in which a comprehensive analysis of the economic and environmental performance of the energy use of biomass was carried out for selected existing facilities throughout the European Union. It is demonstrated that the appropriately organized use of biofuels has significant environmental advantages compared to the use of fossil fuels. Mitigation of global warming is the largest single incentive to use biofuels| However| only a few technologies are economically competitive under prevailing conditions| while others lead to up to 100% higher energy production costs than fossil fuels. Employment effects of using biofuels are small but positive. (C) 2000 Elsevier Science Ltd. All rights reserved. 5384,2000,3,2,Toward a strategic plan for transportation-air quality research| 2000-2010,The challenge of jointly addressing transportation and air quality concerns has been the subject of research for some time| but it reached its apex after passage of the Clean Air Act Amendments of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991. Since that time| the legislative and regulatory context that prompted extensive research has been in continual flux| leading to ever-new areas even as the original agenda set in the early 1990s has yet to be completed. Critical relationships between transportation behavior and air quality impacts have yet to be clarified| and more data and better analytical tools will be necessary before greater understanding is achieved. The advent of new strategies related to telecommuting| e-commerce| vehicle insurance| car sharing| and "sustainability" poses serious questions for the research community. Concurrently| new challenges abound spawned from current and future developments. New air quality standards have redefined the meaning of "clean" air. Air toxics loom as the next focus area from the 1990 amendments. New vehicle and fuel standards are being adopted. Greenhouse gases and global warming pose particular challenges for transportation| but radically new vehicle-fuel systems for cars| trucks| and buses show promise that the transportation community can again rise to meet these challenges. Knowing where the greatest air quality problems exist and how best to address them is the stuff of cutting-edge research| which will pose a challenge into the next decade. It is an exciting time to be in transportation and air quality. 5268,2000,3,3,Transition to CFC-free metered dose inhalers - into the new millennium,Metered dose inhalers (MDIs) are the most popular vehicle for drug delivery into the lungs and some 500 million are manufactured each year. All MDIs marketed prior to 1995 contained chlorofluorocarbons (CFC) as a propellant. These are implicated in the depletion of stratospheric ozone and| except for specific exemptions| their production has been banned since 1996 under the terms of the Montreal Protocol. Hydrofluoroalkanes have been identified as suitable alternatives for MDI propellants but their physico-chemical properties differ significantly from CFCs and an extensive redevelopment and testing programme has been required to demonstrate the safety| quality and efficacy of HFA containing MDIs. Hydrofluoroalkanes contribute to global warming but the benefit to human health through continued MDI availability currently outweighs the environmental concern. Several HFA-MDIs have reached the market and the transition to replace existing CFC-MDIs is now underway. (C) 2000 Elsevier Science B.V. All rights reserved. 5334,2000,3,4,Tropodegradable fluorocarbon replacements for ozone-depleting and global-warming chemicals,Incorporation of certain molecular features into fluorocarbons can decrease the tropospheric lifetime| providing commercially applicable chemicals with low global warming and stratospheric ozone impacts. (C) 2000 Elsevier Science S.A. All rights reserved. 5274,2000,4,4,Twentieth-century change in the climate record for the Front Range| Colorado| USA,The long-term climate records of the Mountain Research Station (MRS) at the University of Colorado cover a range of elevations from the lower montane forest zone (similar to 2000-2400 m)| through the upper montane forest (similar to 2400-2800 m) and subalpine forest (similar to 2800-3300 m) to the alpine tundra (>3300 m) on Niwot Ridge| Colorado. Temperature records from all four MRS sites and the additional high plains site of Longmont (1509 m) are analyzed for the period 1952-1997| after extraction of much extra data from the original thermograph charts. The records are adjusted for instrumental changes where necessary and all four records are judged to be homogenous. Contrasting temporal trends are uncovered at the various elevations with warming at middle elevations and absolute cooling above the treeline in the alpine tundra. The resulting increased surface-based lapse rates do not arise from changes in relative frequencies of airflow types as is shown by a synoptic analysis based on objective airflow indices. Lapse rate increases are most systematic for synoptic classes with westerly components and during fall| winter| and spring. Climate at high elevations of the Front Range appears to be responding in an unusual way to global-warming influences. 5269,2000,2,4,Twentieth-century storm activity along the US east coast,It has been speculated that future global warming will change the frequency and severity of tropical and extratropical storms. The U.S. east coast is heavily impacted by such storms| so it is important to determine their natural temporal variability for the last century during which global warming has been relatively small. Storm surge data obtained from hourly tide gauge records provide a unique quantitative measure of storm duration and intensity| unlike qualitative estimates based on eyewitness reports or meteorological hindcasts. To demonstrate the potential of storm surge data for climate analysis| the authors have evaluated 10 very long records of water level anomalies. An analysis of the hourly tide gauge records along the U.S| east coast shows a considerable interdecadal variation but no discernible long-term trend in the number and intensity of moderate and severe coastal storms during this century. However| sea level rise over the last century has exacerbated the damage to fixed structures from modern storms that would have been relatively minor a century ago. 5291,2000,2,3,Ultra-enhanced spring branch growth in CO2-enriched trees: can it alter the phase of the atmosphere's seasonal CO2 cycle?,Since the early 1960s| the declining phase of the atmosphere's seasonal CO2 cycle has advanced by approximately 7 days in northern temperate latitudes| possibly as a result of increasing temperatures that may be advancing the time of occurrence of what may be called 'climatological spring.' However| just as several different phenomena are thought to have been responsible for the concomitant increase in the amplitude of the atmosphere's seasonal CO2 oscillation| so too may other factors have played a role in bringing about the increasingly earlier spring drawdown of CO2 that has resulted in the advancement of the declining phase of the air's CO2 cycle. One of these factors may be the ongoing rise in the CO2 content of the air itself; for the aerial fertilization effect of this phenomenon may be significantly enhancing the growth of each new season's initial flush of vegetation| which would tend to stimulate the early drawdown of atmospheric CO2 and thereby advance the time of occurrence of what could be called 'biological spring.' Working with sour orange (Citrus aurantium L.) trees that have been growing out-of-doors in open-top chambers for over 10 years in air of either 400 or 700 ppm CO2| this hypothesis was investigated by periodically measuring the lengths| dry weights and leaf chlorophyll concentrations of new branches that emerged from the trees at the start of the 1998 growing season. The data demonstrate that the hypothesis is viable| and that it might possibly account for 2 of the 7 days by which the spring drawdown of the air's CO2 concentration has advanced over the past few decades. (C) 2000 Published by Elsevier Science B.V. 3102,2000,3,4,Uncertainty as information: Narrowing the science-policy gap,Conflict and indecision are hallmarks of environmental policy formulation. Some argue that the requisite information and certainty fall short of scientific standards for decision making; others argue that science is not the issue and that indecisiveness reflects a lack of political willpower. One of the most difficult aspects of translating science into policy is scientific uncertainty. Whereas scientists are familiar with uncertainty and complexity| the public and policy makers often seek certainty and deterministic solutions. We assert that environmental policy is most effective if scientific uncertainty is incorporated into a rigorous decision-theoretic framework as knowledge| not ignorance. The policies that best utilize scientific findings are defined here as those that accommodate the full scope of scientifically based predictions. 5367,2000,3,3,Uncertainty in land-use change and forestry sector mitigation options for global warming: Plantation silviculture versus avoided deforestation,How land-use change and forestry sector options can be used to mitigate global warming will depend on a variety of pending decisions regarding interpretation of the Kyoto Protocol| including treatment of uncertainty. In tropical forest countries| the allocation of effort between plantation silviculture and reduction of deforestation would be influenced by the stringency of requirements regarding certainly. Slowing deforestation offers much greater potential benefits| but the certainty associated with these is much lower than in the case of plantations. In the Brazilian case| deforestation avoidance could produce carbon benefits worth 6-45 times as much as the destructive ranching and logging uses to which the forest is now being converted. Capturing the potential value of carbon benefits from avoided deforestation will depend on increasing our understanding of the deforestation process and consequent ability to reduce the uncertainty associated with the effects of deforestation-avoidance measures. It will also depend on whether carbon credits are defined in terms of a. maximum level of uncertainty. (C) 2000 Elsevier Science Ltd. All rights reserved. 3059,2000,5,4,Understanding nonlinear responses of the climate system to orbital forcing,We have recently introduced the working hypothesis that frequency modulation (FM) of the orbital eccentricity forcing may be one important source of the nonlinearities observed in delta O-18 time series from deep-sea sediment cores (J.A. Rial (1999a) Pacemaking the Ice Ages by frequency modulation of Earth's orbital eccentricity. Science 285| 564-568.) In this paper we shall discuss further evidence of frequency modulation found in data from the Vostok ice core. Analyses of the 430|000-year long| orbitally untuned| time series of CO2| deuterium| aerosol and methane| suggest frequency modulation of the 41 kyr (0.0244 kyr(-1)) obliquity forcing by the 413 kyr-eccentricity signal and its harmonics. Conventional and higher-order spectral analyses show that two distinct spectral peaks at similar to 29 kyr (0.034 kyr(-1)) and similar to 69 kyr (0.014 kyr(-1)) and other| smaller peaks surrounding the 41 kyr obliquity peak are harmonically (nonlinearly) related and likely to be FM-generated sidebands of the obliquity signal. All peaks can be closely matched by the spectrum of an appropriately built theoretical FM signal. A preliminary model| based on the classic logistic growth delay differential equation| reproduces the longer period FM effect and the familiar multiply peaked spectra of the eccentricity band. Since the FM effect appears to be a common feature in climate response| finding out its cause may help understand climate dynamics and global climate change. (C) 2000 Elsevier Science Ltd. All rights reserved. 5150,2000,4,4,Urbanization in the Pacific: environmental change| vulnerability and human security,The world is in the midst of a substantial urban transition| but the impacts of this on the environment and human societies are not fully understood. Very little attention has been paid to urbanization processes in developing countries with smaller populations| despite the evident problems associated with urbanization. There are both biophysical and social vulnerabilities associated with urbanization in the South Pacific and these vulnerabilities affect human security. The biophysical vulnerabilities include the fragile environments of the island nations| limited land resources| shortages of basic resources| and the risks associated with global warming. The ability to respond to these problems is constrained by social vulnerabilities| notably weak economies| difficulties associated with land ownership| and institutional limitations. There is a need for institutional reform| improved planning| better urban resource management| and greater regional cooperation| if Pacific island nations are to respond effectively to rapid urbanization and global change. 3147,2000,2,4,Vegetation variation within and among palustrine wetlands along an altitudinal gradient in KwaZulu-Natal| South Africa,The variation in graminoid species composition and diversity and the distribution of photosynthetic pathways among 66 wetlands in KwaZulu-Natal| South Africa| and within six of these wetlands was described and related to measured physical parameters| using multivariate and univariate techniques. Altitude| which ranged from 550 m to 2120 m| accounted for most variation among wetlands| with an almost complete turnover of species along this gradient. Landform setting was less important in explaining overall species composition| but relationships of individual species were revealed (e.g. Eleocharis dregeana showed an affinity for depressions). Within a wetland there was an almost complete turnover of species along a gradient of wetness| as described using soil morphological criteria. Most species were consistently associated with the same wetness zones across different wetland sites| e.g.| Phragmites australis with the wettest zone| Pycreus macranthus with the intermediate zone| and Eragrostis plana with the least wet zone. The occurrence and abundance of different photosynthetic pathway types depended on altitude and degree of wetness. At high altitudes| C-3 sedges| notably Carex acutiformis| dominated the wettest zone and C-3 and C-4 grasses and sedges dominated the intermediate and least wet zones. At mid altitudes| C-3 and C-4 sedges and C-3 grasses dominated the wettest zone| C-3 and C-4 grasses and sedges dominated the intermediate zone and C-4 grasses dominated the least wet zone. Low altitude sites showed a similar distribution of photosynthetic pathways as mid-altitude sites| but C-3 species were less abundant. Species richness was positively associated with the log of wetland size and| at the level of an individual wetland| species richness and evenness were found to be consistently greater in the intermediate and least wet zone compared with the wettest zone. The management implications of the results are discussed in the light of continuing anthropogenic loss of wetlands in the study area and global climate change. 5218,2000,4,3,Water vapor feedbacks in the ECMWF reanalyses and Hadley Centre climate model,Many studies have been made of the water vapor feedback| in both satellite data and climate model simulations. Most infer the magnitude of the feedback from the variability present in geographical distributions of the key variables| or from their seasonal variations| often using data only over the oceans. It is argued that a more direct measure of the feedback should come from the interannual variability of global mean quantities| because this timescale and space scale is more appropriate for such a global phenomenon. To investigate this suggestion| the feedback derived from the simulations of clear-sky longwave fluxes (CLERA)| which used data from the 15-yr reanalysis project of the European Centre for Medium-Range Weather Forecasts| is compared with simulations by the latest version of the Hadley Centre climate model. Results are taken from an integration of the atmosphere-only version of the climate model with prescribed sea surface temperatures| as well as from a control and a global warming simulation by the coupled ocean-atmosphere version. There is broad consistency between the results from CLERA and the climate model as to the strength of the feedback| although there is considerable scatter in the CLERA results. The signal of changes in the well-mixed greenhouse gases is weak in CLERA but is dominant in the global warming simulation and has to be removed in order to diagnose the water vapor feedback. This result has implications for the exploitation of long time series of satellite and other data to study this and other feedbacks. 3110,2000,4,4,Water vapor| CO2| and temperature profiles in and above a forest - Accuracy assessment of an unattended measurement system,The possibility of a global climate change has increased research interest in the least understood parts of the climate system. One of those parts is the boundary between the land surface of the earth and the lowest part of the planetary boundary layer. The structure of this layer and the exchange processes in it are still incompletely understood for a variety of situations and surfaces| especially in the boreal zone and during the dark parts of the day and the year. Progress in this area requires new data measured continuously and unattended with high accuracy and long-term reliability. A measurement system for profiles of temperature| humidity| and carbon dioxide was designed to meet the above goals. The system used thermocouples and a Li-Cor gas analyzer combined with an array of tubing to suck air from different heights. Turbulent fluctuations of water vapor and carbon dioxide concentrations were smoothed by continuous-flow mixing chambers without moving parts. Half-hourly mean differences in temperature| humidity| and CO2 were measured to better than 0.03 K| 0.015 g kg(-1) and 0.5 mu mol mol(-1)| respectively. These accuracies were confirmed by comparisons with a thermometer-interchange (reversing) system and CO2 profiles theoretically deduced from eddy-correlation fluxes. Daytime temperature and humidity differences over the full height interval (24.5-87.5 m)| as well as over the roughness sublayer part (24.5-58.5 m)| commonly exceeded the estimated errors by five times. The CO2 differences could only be measured reasonably accurately over the entire height interval (24.5-87.5 m) and then only exceeded the error by a factor of 2-3. Temperature and humidity measurements were sufficiently accurate for studies of flux-profile relationships over a forest. The CO2 profiles were accurate only for rough flux estimates and may be especially useful for nighttime studies. 5349,2000,2,3,Will changes in soil organic carbon act as a positive or negative feedback on global warming?,The world's soils contain about 1500 Gt of organic carbon to a depth of 1m and a further 900 Gt from 1-2m. A change of total soil organic carbon by just 10% would thus be equivalent to all the anthropogenic CO2 emitted over 30 years. Warming is likely to increase both the rate of decomposition and net primary production (NPP)| with a fraction of NPP forming new organic carbon. Evidence from various sources can be used to assess whether NPP or the rate of decomposition has the greater temperature sensitivity| and| hence| whether warming is likely to lead to an increase or decrease in soil organic carbon. Evidence is reviewed from laboratory-based incubations| field measurements of organic carbon storage| carbon isotope ratios and soil respiration with either naturally varying temperatures or after experimentally increasing soil temperatures. Estimates of terrestrial carbon stored at the Last Glacial Maximum are also reviewed. The review concludes that the temperature dependence of organic matter decomposition can be best described as: d(T) = exp[3.36 (T - 40)/(T + 31.79)] where d(T) is the normalised decomposition rate at temperature T (in degrees C). In this equation| decomposition rate is normalised to '1' at 40 degrees C. The review concludes by simulating the likely changes in soil organic carbon with warming. In summary| it appears likely that warming will have the effect of reducing soil organic carbon by stimulating decomposition rates more than NPP. However| increasing CO2 is likely to simultaneously have the effect of increasing soil organic carbon through increases in NPP. Any changes are also likely to be very slow. The net effect of changes in soil organic carbon on atmospheric CO2 loading over the next decades to centuries is| therefore| likely to be small. 5303,2000,2,4,Zebra mussels: Enhancement of copper toxicity by high temperature and its relationship with respiration and metabolism,Increase in water temperature from an ambient of 15 degrees C to 20 and 25 degrees C increased the respiration rate in zebra mussels| Dreissena polymorpha| by 50 and 175%| respectively| and increased the toxicity of copper; a 48-hour lethal concentration to kill 50% of the organisms (LC50) of 775 mu g/L at 20 degrees C decreased to 238 mu g/L at 25 degrees C| and a 96-hour LC50 of 487 mu g/L at 20 degrees C reduced to 107 mu g/L at 25 degrees C. The oxygen consumption rate in the presence of 150 mu g/L copper decreased by 16% at 20 degrees C and by 50% at 25 degrees C. Thus| high temperatures may increase the toxicity of copper| and possibly other metals| to zebra mussels. Similar increases in heavy metal toxicity may also accompany global warming| which is expected to raise surface water temperature by 2 to 3 degrees C. Such temperature and heavy metal combinations may also be useful in designing field trials to control this nuisance species. 3042,2001,4,4,A biome classification of China based on plant functional types and the BIOME3 model,A biome classification for China was established based on plant functional types (PFTs) using the BIOME3 model to include 16 biomes. In the eastern part of China| the PFTs of trees determine mostly the physiognomy of landscape. Biomes range from boreal deciduous coniferous forest/woodland| boreal mixed forest/woodland| temperate mixed forest| temperate broad-leaved deciduous forest| warm-temperate broad-leaved evergreen/mixed forest| warm-temperate/cool-temperate evergreen coniferous forest| xeric woodland/scrub| to tropical seasonal and rain forest| and tropical deciduous forest from north to south. In the northern and western part of China| grass is the dominant PFT. From northeast to west and southwest the biomes range from moist savannas| tall grassland| short grassland| dry savannas| arid shrubland/steppe| desert| to alpine tundra/ice/polar desert. Comparisons between the classification introduced here and the four classifications which were established over the past two decades| i.e. the vegetation classification| the vegetation division| the physical ecoregion| and the initial biome classification have showed that the different aims of biome classifications have resulted in different biome schemes each with its own unique characteristics and disadvantages for global change study. The new biome classification relies not only on climatic variables| but also on soil factor| vegetation functional variables| ecophysiological parameters and competition among the PFTs. It is a comprehensive classification that using multivariables better expresses the vegetation distribution and can be compared with world biome classifications. It can be easily used in the response study of Chinese biomes to global change| regionally and globally. 5430,2001,4,4,A closer look at United States and global surface temperature change,We compare the United States and global surface air temperature changes of the past century using the current Goddard Institute for Space Studies (GISS) analysis and the U.S. Historical Climatology Network (USHCN) record [Karl et al.| 1990]. Changes in the GISS analysis subsequent to the documentation by Hansen et al. [1999] are as follows: (1) incorporation of corrections for time-of-observation bias and station history adjustments in the United States based on Easterling et al. [ 1996a]| (2) reclassification of rural| small-town| and urban stations in the United States| southern Canada| and northern Mexico based on satellite measurements of night light intensity [Imhoff et al.| 1997]| and (3) a more flexible urban adjustment than that employed by Hansen et al. [1999]| including reliance: on only unlit stations in the United States and rural stations in the rest of the world for determining long-term trends. We find evidence of local human effects ("urban warming") even in suburban and small-town surface air temperature records| but the effect is modest in magnitude and conceivably could be an artifact of inhomogeneities in the station records. We suggest further studies| including more complete satellite night light analyses. which may clarify the potential urban effect. There are inherent uncertainties in the long-term temperature change at least of the order of 0.1 degreesC for both the U.S. mean and the global mean. Nevertheless| it is clear that the post- 1930s cooling was much larger in the United States than in the global mean. The U.S. mean temperature has now reached a level comparable to that of the 1930s| while the global temperature is now far above the levels earlier in the century. The successive periods of global warming (1900-1940)| cooling (1940-1965)| and warming (1965-2000) in the 20th century show distinctive patterns of temperature change suggestive of roles for both climate forcings and dynamical variability. The U.S. was warm in 2000 but cooler than the warmest years in the 1930s and 1990s. Global temperature was moderately high in 2000 despite a lingering La Nina in the Pacific Ocean. 5616,2001,3,4,A decision-analytic framework for impact assessment - Part I: LCA and decision analysis,Life-cycle assessments (LCAs) are conducted to satisfy the aspiration of decision makers to consider the environment in their decision making. This paper reviews decision analysis and discusses how it can be used to structure the assessment and to integrate characterization and valuation. The decision analytic concepts of objectives (goals) and attributes (indicators of the degree to which an objective is achieved) are used to describe steps of the assessment of the entire impact chain. Decision analysis distinguishes among different types of objectives and attributes; it describes how these relate to each other. Impact indicators such as the Human Toxicity Potential are constructed attributes. A means-ends objectives network can show how the different constructed attributes relate to the objective of protecting the environment. As LCA takes disparate environmental impacts into account| it needs to assess their relative importance. Trade-off methods in decision analysis are grouped into utility theory and multicriteria decision aids; they have different advantages and disadvantages| but are all more sophisticated than simple weighting. The performance of the different trade-off methods has not yet been tested in an LCA context. In the second part of the paper| we present criteria for the development of characterization methods. 5579,2001,4,4,A measurement of the quiet network contribution to solar irradiance variation,A large increase in quiet network area since the 17(th) century Maunder Minimum has been suggested as a mechanism for increasing solar irradiance sufficiently to drive global warming. We show that this mechanism requires essentially complete disappearance of network proceeding back in time to the beginning of the 20(th) century. This disappearance is ruled out by the many Ca K spectroheliograms taken since the discovery of the network in the early 1890's. Furthermore| network area measurements we have carried out on Ca K spectroheliograms digitized from the Mt Wilson and NSO/Sacramento Peak archives| for the nine solar activity minima between 1914 and 1996| show no evidence of network area variations large enough to produce a significant long-term component of total irradiance variation. A network brightness variation of sufficient magnitude is also unlikely| given the linear dependence of solar microwave nux on area of bright structures. More generally| recent analyses of cycle 21| 22 pyrheliometry| and of broadband stellar photometry| provide little support for any long-term irradiance component These results do not rule out a secular irradiance increase. But they suggest that high climate sensitivity to the relatively small changes in solar total and UV irradiance that have been observed| provides a more likely explanation of the global temperature-solar activity correlation. 5514,2001,3,3,A mechanistic model of whole-tract digestion and methanogenesis in the lactating dairy cow: Model development| evaluation| and application,Dietary intervention to reduce methane emissions from lactating dairy cattle is both environmentally and nutritionally desirable due to the importance of methane as a causative agent in global warming and as a significant loss of feed energy. Reliable prediction systems for methane production over a range of dietary inputs could be used to develop novel dietary regimes for the limitation of feed energy loss to methane. This investigation builds on previous attempts at modeling methanogenesis and involves the development of a dynamic mechanistic model of whole-rumen function. The model incorporates modifications to certain ruminal fermentation parameters and the addition of a postruminal digestive element. Regression analysis showed good agreement between observed and predicted results for experimental data taken from the literature (r(2) = 0.76| root mean square prediction error = 15.4%). Evaluation of model predictions for experimental observations from five calorimetry studies (67 observations) with lactating dairy cows at the Centre for Dairy Research| in Reading| U.K|| shows an underprediction (2.1 MJ/d) of methane production (r(2) = 0.46| root mean square prediction error = 12.4%). Application of the model to develop diets for minimizing methanogenesis indicated a need to limit the ratio of lipogenic to glucogenic VFA in the rumen and hindgut. This may be achieved by replacing soluble sugars in the concentrate with starch or substituting corn silage for grass silage. On a herd basis| the model predicted that increasing dietary energy intake per cow can minimize the annual loss of feed energy through methane production. The mechanistic model is a valuable tool for predicting methane emissions from dairy cows. 5478,2001,2,4,A modeling-GIS approach for assessing irrigation effects on soil salinisation under global warming conditions,Soil salinisation is very often due to excessive irrigation. However| irrigation is absolutely essential for obtaining reliable crop yields| particularly under predicted global warming conditions. A simple methodology for assessing the salinisation risk for any water management situation and under predicted global warming conditions is presented. The methodology is illustrated by the assessment of irrigation effects on soil salinity at San Antonio del Sur Valley| in the southeast of Cuba. Irrigation from a new dam will support agriculture in the Valley| but at the same rime soil salinity is expected to increase. Soil electrical conductivity at several depths and topographical altitudes were used to create raster layers in a Geographic Information System (GIS)| thus| determining the border of the saline-affected zones by a GIS analysis. Water-table depth at the border of the saline zones was assumed to be 2 m. The physically based SWAP model was used to predict future water-table depths after irrigation begins and under global warming conditions. Future temperature and precipitation daily values were calculated from a linear increase/decrease of the daily values corresponding to a typical year| according to a global-change forecast for the zone. Soil hydraulic properties were estimated from pedotransfer function and published soil data. Simulated results predict a fast water-table raise of 1 m| due to the increase of irrigation water. B orders of the new saline zones under these conditions (i.e. the places where the water-table is at a 2 m depth) were calculated using a digital terrain model| assuming that the water-table rose 1 m over the whole valley. According to the simulation results| the original saline zones of the valley will be enlarged from 31.4 to 96.8 ha 15 years after the scheduled start of irrigation. The methodology could be used by farmers and decision-makers to select the most suitable water management solution considering both economical and environmental criteria. (C) 2001 Elsevier Science B.V. Ah rights reserved. 5563,2001,3,3,A new CO2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid,A new disposal process for anthropogenic CO: via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps: (1) CaSiO3 + 2CH(3)COOH --> Ca2+ + 2CH(3)COO(-) + H2O + SiO2. (2) Ca2+ + 2CH(3)COO(-) + CO2 + H2O --> CaCO(3)down arrow+ 2CH(3)COOH. Step (1) is the extraction of calcium ions by acetic acid from calcium silicate| for example| wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions by CO2 injection. The Gibbs free energy change of each step is negative; the reactions would proceed spontaneously without consuming large amounts of energy. The CO2 would be captured from the concentrated emission sources such as thermal power plant| and be disposed of and sequestrated in the form of calcium carbonate. The feasibility of the proposed process was evaluated through a process design based on the experimental results of the reaction kinetics. The operational energy consumption was 20.4 MW for the disposal of CO2 produced by a 100-MW thermal power plant. (C) 2001 Elsevier Science Ltd. All rights reserved. 5404,2001,4,2,A nonlinear impulse response model of the coupled carbon cycle-climate system (NICCS),Impulse-response-function (IRF) models are designed for applications requiring a large number of climate change simulations| such as multi-scenario climate impact studies or cost-benefit integrated-assessment studies. The models apply linear response theory to reproduce the characteristics of the climate response to external forcing computed with sophisticated state-of-the-art climate models like general circulation models of the physical ocean-atmosphere system and three-dimensional oceanic-plus-terrestrial carbon cycle models. Although highly computer efficient| IRF models are nonetheless capable of reproducing the full set of climate-change information generated by the complex models against which they are calibrated. While limited in principle to the linear response regime (less than about 3 degreesC global-mean temperature change)| the applicability of the IRF model presented has been extended into the nonlinear domain through explicit treatment of the climate system's dominant nonlinearities: CO2 chemistry in ocean water| CO2 fertilization of land biota| and sublinear radiative forcing. The resultant nonlinear impulse-response model of the coupled carbon cycle-climate system (NICCS) computes the temporal evolution of spatial patterns of climate change for four climate variables of particular relevance for climate impact studies: near-surface temperature| cloud cover| precipitation| and sea level. The space-time response characteristics of the model are derived from an EOF analysis of a transient 850-year greenhouse warming simulation with the Hamburg atmosphere-ocean general circulation model ECHAM3-LSG and a similar response experiment with the Hamburg carbon cycle model HAMOCC. The model is applied to two long-term CO2 emission scenarios| demonstrating that the use of all currently estimated fossil fuel resources would carry the Earth's climate far beyond the range of climate change for which reliable quantitative predictions are possible today| and that even a freezing of emissions to present-day levels would cause a major global warming in the long term. 5399,2001,2,4,A potential interaction between sea-level rise and global warming: implications for coastal stability on the Mississippi River Deltaic Plain,A portion of the southeastern United States is currently experiencing the most severe drought on record. Rainfall deficits accumulated since 1998 have led to a twofold increase in mean annual salinity in the study area| a wetland landbridge located in the Lake Pontchartrain Estuary in southeastern Louisiana. Global circulation models have predicted a rise in both the frequency and amplitude of extreme weather if global warming continues. This indicates a-threat to the stability of deltaic plains| particularly those with altered hydrologies. Throughout the Mississippi River Deltaic Plain| river control structures have eliminated freshwater inputs. Generally| this should lead to increases in salinity that can become particularly acute during drought events. Such conditions have been shown to play a decisive role in plant community ecology| an important force in deltaic plain stability| Beyond certain thresholds| these conditions can have detrimental effects upon primary production. The accumulation of primary production deficits may lead to increases in the rate of relative sea-level rise. Though the drought is not proven to be the result of global warming| this event shows that coastal ecology is sensitive to drought conditions and any increase will be detrimental to floodplain stability. (C) 2002 Elsevier Science B.V. All rights reserved. 5516,2001,3,4,A search for a freonless gas mixture for glass RPC,We have operated successfully glass resistive plate counters in the streamer mode at the BELLE experiment by using a nonflammable gas mixture of argon 30 %| butane-silver 8 %| and freon| HFC-134a 62 %. This freon is non-ozone-depleting but has a high global warming potential (1300 times higher than that of CO2). Thus freon gases might be unusable in the near future. We tested the performance of a glass resistive plate counter operated in the streamer mode with an alternative gas mixtures of argon| butane| CO2| and/or O-2 gases and found an efficiency of about 90 %. 2953,2001,2,4,A time-series study of particulate matter export in the North Pacific Subtropical Gyre based on Th-234 : U-238 disequilibrium,Depth profiles of total Th-234 (dissolved+particulate) were collected at Station ALOHA (22 degrees 45N| 158 degrees 00W) in the North Pacific Subtropical Gyre during 9 cruises from April 1999 to March 2000. Samples were collected and processed by a new 2 L technique that enables more detailed depth resolution then previous Th-234 studies. Significant zones of particle export (Th-234 deficiency) and particle remineralization (Th-234 excess) were measured both temporally and with depth. Th-234 derived particulate carbon (PC) and nitrogen (PN) fluxes were determined with steady-state and non-steady-state models and PC/Th-234 and PN/Th-234 ratios measured with both in situ pumps and free-drifting particle interceptor traps deployed at 150 m. Th-234 based export estimates of 4.0 +/- 2.3 mmol C m(-2) d(-1) and 0.53 +/- 0.19 mmol N m(-2) d(-1)| were approximately 60% higher than those measured in PIT style sediment traps from the same time period| 2.4 +/- 0.2 mmol C m(-2) d(-1) and 0.32 +/- 0.08 mmol N m(-2) d(-1). Most of this difference is attributable to two large export events that occurred during October and December 1999| when traps undercollected for Th-234 by a factor of 2 to 4. Th-234 export (ThE) ratios based on Th-234 derived PC flux/C-14 based primary production ranged from 4% to 22% (average = 8.8%). Our results confirm the recent estimates of C export by Emerson et al. (Nature 389 (1997) 951) and Sonnerup et al. (Deep-Sea Research I 46 (1999) 777) and indicate that C export from the oligotrophic ocean must be considered when discussing C sequestration in global climate change. (C) 2001 Elsevier Science Ltd. All rights reserved. 5443,2001,3,3,A transition toward a sustainable energy future: feasibility assessment and development strategies of wind power in Taiwan,While the international community has yet to achieve a consensus on the operational details of implementing the Kyoto Protocol| the rapidly increasing consumption of fossil fuels and the CO| emissions produced in the industrializing developing countries further obscure the prospects for combating global warming. This study analyzes the problems of energy utilization in Taiwan as an illustrative example| and explores the strategies for increasing the market penetration of wind power in the traditional energy structure dominated by fossil fuels and nuclear energy. Decentrally produced wind power would contribute to establishing an autonomous and disaster-resilient power supply system. Replacing partial coal-based power generation with the full exploitation of wind energy would result in annual reductions of 9.8 million tons of CO| in Taiwan. The key barrier to utilizing wind energy lies mainly in the lack of political impetus and a framework for promoting renewable energy in Taiwan. Priority tasks to allow wind power to penetrate the energy market include establishing legislative prioritization for renewable energy| setting premium prices for power from wind turbines| providing direct support of investment costs| raising awareness| etc. (C) 2001 Elsevier Science Ltd. All All rights reserved. 3035,2001,2,4,Abiotic vs. biotic influences on habitat selection of coexisting species: Climate change impacts?,Species are commonly segregated along gradients of microclimate and vegetation. I explore the question of whether segregation is the result of microhabitat partitioning (biotic effects) or choice of differing microclimates (abiotic effects). I explored this question for four ground-nesting bird species that an segregated along a microclimate and vegetation gradient in Arizona. Birds shifted position of their nests on the microhabitat and microclimate gradient in response to changing precipitation over nine years. Similarly| annual bird abundance varied with precipitation across 12 yr. Those shifts in abundance and nesting microhabitat with changing precipitation demonstrate the importance of abiotic influences on bird distributions and habitat choice. However| nest-site shifts and microhabitat use also appear to be influenced by interactions among coexisting species. Moreover| shifts in habitat use by all species caused nest predation (i.e.| biotic) costs that increased with increasing distance along the microclimate gradient. These results indicate that abiotic and biotic costs can strongly interact to influence microhabitat choice and abundances of coexisting species. Global climate change impacts have been considered largely in terms of simple distributional shifts| but these results indicate that shifts can also increase biotic costs when species move into habitat types for which they are poorly adapted or that create new biotic interactions. 5550,2001,5,4,Absence of deep-water formation in the Labrador Sea during the last interglacial period,The two main constituent water masses of the deep North Atlantic Ocean-North Atlantic Deep Water at the bottom and Labrador Sea Water at an intermediate level-are currently formed in the Nordic seas and the Labrador Sea| respectively(1). The rate of formation of these two water masses tightly governs the strength of the global ocean circulation and the associated heat transport across the North Atlantic Ocean(2). Numerical simulations have suggested a possible shut-down of Labrador Sea Water formation as a consequence of global warming(3). Here we use micropalaeontological data and stable isotope measurements in both planktonic and benthic foraminifera from deep Labrador Sea cores to investigate the density structure of the water column during the last interglacial period| which was thought to be about 2 degreesC warmer than present(4). Our results indicate that today's stratification between Labrador Sea Water and North Atlantic Deep Water never developed during the last interglacial period. Instead| a buoyant surface layer was present above a single water mass originating from the Nordic seas. Thus the present situation| with an active site of intermediate-water formation in the Labrador Sea| which settled some 7|000 years ago| has no analogue throughout the last climate cycle. 5669,2001,3,3,Absorption processes - Classic chemical engineering in combating global warming,Development is described of the theory of absorption as a classic chemical engineering process. Two particular elements of this theory are discussed| namely| multicomponent mass transport and cellular convection. The role of carbon dioxide in generating the greenhouse effect is outlined| along with methods for the abatement of CO2. The importance of modem absorption processes is shown using| as an example| the capture and sequestration of CO2 that accompanies the North Sea natural gas. 5508,2001,2,4,Accumulation and temperature changes in Princess Elizabeth Land| Antarctica in the past 250 years,A 50 m firn core drilled in Princess Elizabeth Land| Antarctica| during the 1996/1997 Chinese First Antarctic Inland Expedition| has been measured for delta O-18 and major ions. Based on these data| the features of the climate change in the investigated region in the past 250 years have first been studied. In the past 250 years| the change trend of climate in this legion can be divided into two periods by the year 1860. Both the temperature and accumulation rate display increasing trend before 1860| while after 1860| the decreasing trend of the temperature is obvious but the change of the accumulation rate is not clear. Although both the temperature and the accumulation rate are increasing in the past 50 years| they are not the highest values in the past 250 years. Sc it is clear that the climate change in this region during this period does not reflect recent global warming.
5526,2001,3,2,Advanced materials for global carbon dioxide recycling,CO2 emission increase inducing global Warming occurs mostly with the growth of the economic activity. Global CO recycling can prevent global warming and supply abundant renewable energy. Global CO2 recycling consists of three district. The electricity is generated by solar cells on deserts. At coasts close to the deserts| the electricity is used for hydrogen production by seawater electrolysis and hydrogen is used for methane production by the reaction with CO2. Methane (CH4) is liquefied and transported to energy consuming districts where after CH4 is used as a fuel CO2 is recovered| liquefied anti transported to the coasts close to the deserts| Ii;ey materials necessary for the global CO2 recycling are the anode and cathode for seawater electrolysis and the catalyst for CO2 conversion All uf them have been tailored by us. amorphous and nanocrystalline nickel alloys are active cathodes for hydrogen production in seawater electrolysis. Anodically deposited nanocrystalline Mn-Mo and Mn-W oxides are the unique substance which can evolve oxygen with 100% efficiency without evolving chlorine in seawater electrolysis. Amorphous Ni-Zr alloys ale excellent precursors of catalysts for conversion of CO2 into CH4 by the reaction with hydrogen at 1 atm. A prototype CO2 recycling plant to supply clean energy preventing global warming has been built on the roof of our Institute (IMR) in 1996 using these key materials and has been operating successfully| (C) 2001 Elsevier Science B.V. All lights reserved. 3034,2001,5,4,Alkenone temperature and carbon isotope records: Temporal resolution| offsets| and regionality,Over the last decade the number of paleoceanographic studies presenting and discussing alkenone-derived sea surface temperature (SST) records and carbon isotope ratios of alkenones (delta C-13(alkenones)) has increased rapidly. This short review paper summarizes the state of knowledge about SST variability determined by alkenone paleothermometry in sediment trap studies and investigations of marine sediments for timescales of single to millions of years. In particular from the evaluation of Quaternary records| characteristic temperature pattern have emerged that mismatch with SST curves estimated by other methods| e.g.| foraminiferal stable oxygen isotopes and transfer functions. In future studies the spatial distribution of such variance patterns typically observed in alkenone SST curves should be checked in order to better understand their meaning for ocean circulation changes and a possible relationship to global climate change. On the other hand| certain physical and biological processes have the potential to put the reliability of alkenone SST curves into question. Accordingly| examples for possible effects of bioturbational mixing| lateral transport of remote alkenones| diagnetic alteration and degradation of alkenone composition| biogeographic and temporal diversity changes in alkenone-producing algae| as well as the influence of changes in salinity and nutrient conditions on the alkenone paleotemperature signal| are briefly mentioned| highlighting the need for more detailed future studies on these issues. Finally| a short summary on the status of the use of the delta C-13(alkenones) signal as a proxy for past variations in the carbon dioxide pressure (PCO2) in ocean surface waters and related problems is given. 3052,2001,3,3,Amazonian deforestation: Regional and global issues,How does the deforestation of Amazonia affect global and regional climates? What arc the roles of these changes on Amazonian ecosystems? We have concluded that the relation between Regional Climate Changes (RCC) and Global Climate Change (GCC) is directly associated with anthropogenic activities and therefore sensitive to social| economical and political interventions. The RCCs are caused by actions within the realm of the Brazilian sociopolitical scenario| and prone to changes through the implementation of public policies regulating the sustained use of the renewable resources. The GCCs belong to an international arena| and are caused by the high emission rates of greenhouse gases by the developed countries. The effects of the RCCs could be abated if the developed countries would endeavor to reduce the present emission levels as documented in IPCC meetings and collaborate in the implementation of a regulation to curb the carbon emissions| in accordance to the Kyoto Protocol. 5398,2001,3,4,Ammonia abatement and its impact on emissions of nitrous oxide and methane - Part 2: application for Europe,Agricultural emissions of NH3| N2O| and CH4 come| to a large extent| from common sources. It has been demonstrated that controlling NH3 emissions through application of technical measures might have an impact on emissions of N2O and CH4. This paper presents estimates of NH3| N2O and CH4 emissions from European agriculture for 1990 and four scenarios for the year 2010. The first scenario assumes no specific NH3 abatement| but emissions of all three gases decline between 1990 and 2010 as a result of projected reductions in animal numbers and fertiliser consumption in Europe. The other three scenarios assume different levels of NH3 abatement in Europe| including the maximum feasible reduction case. They are compared with respect to their effect on emissions of N2O and CH4. The results indicate that in Europe| abating agricultural emissions of NH3 may cause releases of N2O from this sector up to 15% higher than in the case of no NH3 control. There may be substantial differences in the observed effects between various countries depending on the degree and type of NH3 control options applied. The effect of NH3 abatement on CH4 emissions was found to be negligible. c| 2001 Elsevier Science Ltd. All rights reserved. 5397,2001,3,4,Ammonia abatement and its impact on emissions of nitrous oxide and methane in Europeb - Part 1: method,Agriculture is an important source of NH3| which contributes to acidification and eutrophication| as well as emissions of the greenhouse gases CH4 and N2O. Because of their common sources| emission reduction measures for one of these gases may affect emissions of others. These interrelations are often ignored in policy making. This study presents an analysis of the effects of measures to reduce NH3 emissions on emissions of N2O and CH4 from agriculture in Europe. The analysis combines information from the NH3 module of the Regional Air pollution INformation and Simulation (RAINS) model for Europe with the IPCC method for national greenhouse gas inventories. The IPCC method for estimating agricultural emissions of N2O and CH4 is adjusted in order to use it in combination with the RAINS database for the European agricultural sector. As an example| vie applied the adjusted method to the agricultural sector in the Netherlands and found that application of several NH3 abatement options may result in a substantial increase in N2O emissions while the effect on CH4 emissions is relatively small. In Part 2 of this paper we focus on the resulting emissions for all European countries for 1990 and 2010. (C) 2001 Elsevier Science Ltd. All rights reserved. 5595,2001,3,4,Amorphous silicon and tungsten etching employing environmentally benign plasma process,A novel dry etching process for amorphous silicon (a-Si) and tungsten (W) for chemical vapor deposition (CVD) chamber cleaning has been performed by electron cyclotron resonance (ECR) O-2 plasma employing a solid-material evaporation system where fluorocarbon species are produced from fluorinated ethylene propylene (FEP) by CO2 laser evaporation for preventing global warming. This process enables us to realize etching of materials without using any perfluorocompound (PFC) feed gases which have a high global warming potential (GWP). Etching characteristics together with diagnostics of the F atom density| CFx (x = 1-3) radical densities| electron density and temperature have been investigated as functions of pressure. As a result| it was found that etching rates of a-Si and W films were determined based on the F atom density| ion flux and ion bombardment energy. Furthermore| etching rates of a-Si and W films increased by heating the fluorocarbon species before introducing them into the plasma reactor. Thus| high rates of etching of a-Si and W films were successfully achieved by this novel etching process compared with conventional etching using ECR plasma with CF4/O-2 feed gases. 5554,2001,3,3,An alternative approach to establishing trade-offs among greenhouse gases,The Kyoto Protocol permits countries to meet part of their emission reduction obligations by cutting back on gases other than CO2 (ref. 1). This approach requires a definition of trade-offs among the radiatively active gases. The Intergovernmental Panel on Climate Change has suggested global warming potentials for this purpose(2)| which use the accumulated radiative forcing of each gas by a set time horizon to establish emission equivalence. But it has been suggested that this approach has serious shortcomings: damages or abatement costs are not considered(3-10) and the choice of time horizon for calculating cumulative radiative force is critical| but arbitrary(5). Here we describe an alternative framework for determining emission equivalence between radiatively active gases that addresses these weaknesses. We focus on limiting temperature change and rate of temperature change| but our framework is also applicable to other objectives. For a proposed ceiling| we calculate how much one should be willing to pay for emitting an additional unit of each gas. The relative prices then determine the trade-off between gases at each point in time| taking into account economical as well as physical considerations. Our analysis shows that the relative prices are sensitive to the lifetime of the gases| the choice of target and the proximity of the target| making short-lived gases more expensive to emit as we approach the prescribed ceiling. 3033,2001,2,4,An empirical mechanistic framework for heat-related illness,A physiologically based| mechanistic framework was developed to understand key risk factors associated with adverse health effects from heat waves. The framework consists of a number of integrated transdisciplinary modules. Environmental conditions and behavioral responses link to a physiological model| which predicts core temperature. Core temperature over time is then converted into a time-at-temperature metric. The output of the framework is a heat-related health effects index (HEI)| reflecting the potential relative severity of the heat stress on health. The framework is flexible| allowing the individual models to be adapted to conditions at specific locations and to be updated as new information becomes available. Scenario analyses are easily accommodated| enabling the framework to evaluate issues such as intervention strategies and the possible effects of global climate change on heat-related illnesses. The framework and an initial set of component models were applied to conditions during the 1995 Chicago event and the results compared with published studies. For individuals| there was reasonably good agreement between HEI ratios and actual mortality risk ratios when comparing indoor versus outdoor environments. When aggregating across populations| predicted HEI ratios were significantly smaller than actual mortality ratios when comparing healthy versus compromised populations| supporting the notion that mortality may not be the best indicator of heat stress effects. Future work should include refinement of the initial models and application to other cities and heat events. 2991,2001,4,4,An empirical method for the determination of the complex refractive index of size-fractionated atmospheric aerosols for radiative transfer calculations,To adequately assess the effects of atmospheric aerosols on climate| their optical constants (scattering and absorption coefficients) must be known. The absorption and scattering coefficients of the aerosols are derived from the real and imaginary parts of the complex refractive index and are dependent on their size and chemical composition. Because aerosol properties vary significantly with location| it is difficult to assign values for the absorption and scattering of solar radiation by aerosols in models of global climate change| This study reports a new method of collecting size-fractionated atmospheric aerosol samples for the purpose of directly measuring their transmission and reflectance spectra followed by the determination of the complex refractive index across the entire atmospherically relevant spectral range. The samples were collected with a modified Sierra high-volume cascade impactor with the usual filter collection surfaces replaced with Teflon sheets machined to hold quartz (ultraviolet [UV]/visible transparent) and/or silver chloride (infrared transparent) sample collection plates. Reflectance and transmission spectra can be obtained on the aerosol samples directly as a function of wavelength| from 280 mn to 2.5 mum| with an integrating sphere coupled to an UV/visible or a Fourier transform infrared (FTIR) spectrophotometer. The effective real and imaginary components of the refractive index of the bulk sample material can then be approximated| as a function of wavelength| from the sample spectra| preliminary results are presented for carbon soot samples generated in the laboratory and for standard diesel soot samples in the UV/visible spectral range. These are compared to results obtained for size-fractionated atmospheric aerosol samples collected near Pasco| WA| West Mesa| AZ| and Argonne| IL. 3027,2001,4,4,An empirical model of carbon fluxes in Russian tundra,This study presents an empirical model based on la GIS approach| which was constructed to estimate the large-scale carbon fluxes over the entire Russian tundra zone. The model has four main blocks: (i) the computer map of tundra landscapes; (ii) data base of long-term weather records; (iii) the submodel of phytomass seasonal dynamics; and (iv) the submodel of carbon fluxes. The model uses exclusively original in situ diurnal CO2 flux chamber measurements (423 sample plots) conducted during six field seasons (1993-98). The research sites represent the main tundra biome landscapes (arctic| typical| south shrub and mountain tundras) in the latitudinal diapason of 65-74 degreesN and longitudinal profile of 63 degreesE-172 degreesW. The greatest possible diversity of major ecosystem types within the different landscapes was investigated. The majority of the phytomass data used was obtained from the same sample plots. The submodel of carbon fluxes has two dependent [GPP| Gross Respiration (GR)I and several input variables lair temperature| PAR| aboveground phytomass components). The model demonstrates a good correspondence with other independent regional and biome estimates and carbon flux seasonal patterns. The annual GPP of Russian tundra zone for the area of 235x10(6) ha was estimated as -485.8+/-34.6x10(6) tC| GR as +474.2 +/- 35.0x10(6) tC| and NF as -11.6 +/- 40.8x10(6) tC| which possibly corresponds to an equilibrium state of carbon balance during the climatic period studied (the first half of the 20th century). The results advocate that simple regression-based models are useful for extrapolating carbon fluxes from small to large spatial scales. 5611,2001,2,4,Annual methane emission from Finnish mires estimated from eddy covariance campaign measurements,Measurements of landscape-scale methane emission were made over an aapa mire near Kaamanen in Finnish Lapland (69 degrees 8' N| 27 degrees 16' E| 155 m ASL. Emissions were measured during the spring thaw| in summer and in autumn. No effect of water table position on CH4 emission was found as the water table remained at or above the surface of the peat. Methane emission fluxes increased with surface temperature from which an activation energy of -99 kJ mol(-1) was obtained. Annual emission from the site| modelled from temperature regression and short-term flux measurements made in three separate years| was calculated to be 5.5 +/- 0.4 g CH4 m(-2) y(-1) of which 0.6 +/-0.1 g CH4 m(-2) y(-1) (11%) was released during the spring thaw which lasted 20 to 30 days. The effect of global warming on the CH4 budget of the site was estimated using the central scenario of the SILMU (Finnish Research Programme on Climate Change) model which predicts annual mean temperature increases of 1.2| 2.4 and 4.4 degreesC in 2020| 2050 and 2100| respectively. Maximum enhancements in CH4 emission due to warming were calculated to be 18| 40 and 84% for 2020| 2050 and 2100| respectively. Actual increases may be smaller because prediction of changes in water table are highly uncertain. 5658,2001,2,4,Anomalies and trends of sea-ice extent and atmospheric circulation in the Nordic Seas during the period 1864-1998,The extent of ice in the Nordic Seas measured in April has decreased by similar to 33% over the past 135 yr. Retrospective comparison indicates that the recent decrease in the ice extent is within the range of variability observed since the eighteenth century. Temporal| monotonically reduced extreme events occur with intervals of 12-14 yr| suggesting that series longer than similar to 30 yr should be considered to obtain statistical significance regarding temporal changes. Otherwise| decadal temperature variation is also found in the northbound warmer ocean currents. The temperature in the upper layers of these currents seems moreover to have increased by the order of 1 degreesC since the cooling during the Little Ice Age. This temperature increase accounts for most of the ice extent reduction since similar to 1860. A strong negative correlation is found between the larger North Atlantic oscillation (NAO) winter index and the Nordic Seas April ice extent| and a corresponding positive correlation is observed for the Newfoundland-Labrador Sea. It is not until the warming of the Arctic| 1905-30| that the NAO winter index shows repeated positive values over a number of sequential years| corresponding to repeated northward fluxes of warmer air over the Nordic Seas during the winter. An analog repetition of southward fluxes of colder air during wintertime occurs during the cooling period in the 1960s. Concurrently| the temperature in the ocean surface layers was lower than normal during the warming event and higher than normal during the cooling event. Northward atmospheric winter fluxes are observed after the enhanced global warming after similar to 1970| and| for the first time over the period considered| a positive correlation is observed between atmospheric and oceanic reducing effects on the ice extent. The enhanced global warming over the past two decades seems also to be manifest in an intensified winter circulation at higher latitudes| rather than a contemporary change in the Arctic Ocean surface temperature. 2957,2001,2,2,Anthropogenic climate change shown by local wave conditions in the North Sea,In the central North Sea we have observed an increase in the frequency of eastwardly propagating waves in the last 4 decades. To assess the significance of this change| wave statistics for the 20th century were reconstructed with a statistical model With a linear multivariate technique (redundancy analysis)| monthly mean air pressure fields over the North Atlantic and Western Europe were downscaled on the intramonthly frequency of directional wave propagation. When compared against this reference| the recent change appears statistically significant at the 5% level. In order to investigate the reason for this local climatic change| the reconstruction was compared with the downscaled results of control and transient GCM scenarios (ECHAM4-OPYC3) and with the results obtained in a high-resolution time-slice experiment with increased concentrations of greenhouse gases and aerosols. Both estimates are qualitatively consistent with the changes observed in the last 4 decades| We suggest that the recent increase in eastward propagation is a local manifestation of anthropogenic global climate change. 5440,2001,4,4,Application of AMS radiocarbon in earth system science studies,Radiocarbon| a cosmic ray-produced isotope| is one of the most important tracers in Earth system sciences. The strong involvement of carbon in the biosphere and its half life of 5720 years are reflected in appropriate applications in archeology| as well as in the Earth system sciences. Radiocarbon dating had an important turning point in 1977 with the discovery that mass spectrometry with tandem acceleration could be used to measure C-14. This new technique| known as AMS or accelerator mass spectrometry reduced the required sample size to the order of mg| three orders of magnitude smaller than for conventional techniques| thus opening the range of applicability of C-14 studies to a much wider range of samples. However| the application has been complicated by two major activities of human beings on a global scale: the extensive usage of fossil fuel since the industrial revolution and nuclear testing in the atmosphere| which have influenced the natural balance of radiocarbon in the atmosphere. However| the separation of bomb-produced carbon from natural background carbon has produced a very fruitful understanding of the global carbon cycle and the conveyor belt system in the ocean| which will be essential for understanding global environmental problems| such as global warming| in the coming century. Carbon cycle studies in Korea have been made since the early 1990s. The studies include monitoring of CO2 concentrations in the atmosphere| stable isotope studies| and carbon cycle studies in the sea around Korea. The opening of the AMS facility at Seoul National University (SNU) will enhance carbon studies in Earth system sciences greatly in the future. 5448,2001,3,4,Application of high-pressure swing adsorption process for improvement of CO2 recovery system from flue gas,Although the super cold separator applied to the system for CO2 recovery from flue gas can produce pure CO2 liquid| the CO2 recovery efficiency is low. Therefore| the addition of a PSA plant was considered for the secondary CO2 recovery from the noncondensing gas to improve the efficiency. The PSA plant was operated for adsorption at the same pressure as that of the super cold separator and for desorption at the atmospheric pressure. From both the simulation and the experimental data| it was confirmed that CO2 could be concentrated from 50% in the noncondensing gas to 70% in the recovery gas by the PSA plant and the CO2 recovery efficiency of the plant was about 90%. 5544,2001,3,3,Application of the Life Cycle Assessment methodology to agricultural production: an example of sugar beet production with different forms of nitrogen fertilisers,The suitability of the Life Cycle Assessment (LCA) methodology to analyse the environmental impact of agricultural production is investigated. The first part of an LCA is an inventory of all the resources used and emissions released due to the system under investigation. In the following step| i.e. the Life Cycle Impact Assessment the inventory data were analysed and aggregated in order to finally get one index representing the total environmental burden. For the Life Cycle Impact Assessment (LCIA) the Eco-indicator 95 method has been chosen| because this is a well-documented and regularly applied impact assessment method. The resulting index is called Eco-indicator value. The higher the Eco-indicator value the stronger is the total environmental impact of an analysed system. A sugar beet field experiment conducted in northeastern Germany was chosen as an example for the analysis. In this experiment three different nitrogen fertilisers (calcium ammonium nitrate = CAN| urea ammonium nitrate solution = UAN| urea) were used at optimum N rates. The obtained Eco-indicator values were clearly different for the N fertilisers used in the sugar beet trial. The highest value was observed for the system where urea was used as N source. The lowest Eco-indicator value has been calculated for the CAN system. The differences are mainly due to different ammonia volatilisation after application of the N fertilisers. For all the systems the environmental effects of acidification and eutrophication contributed most to the total Eco-indicator value. The results show that the LCA methodology is basically suitable to assess the environmental impact associated with agricultural production. A comparative analysis of the system's contribution to global warming| acidification| eutrophication and summer smog is possible. However| some important environmental issues are missing in the Eco-indicator 95 method (e.g. the use of resources and land). (C) 2001 Elsevier Science B.V. All rights reserved. 5394,2001,3,4,Applying a gas mixture containing c-C4F8 as an insulation medium,This paper studies the possibility of applying a gas mixture containing c-C4F8 in the gas insulation of power equipment. Environmental aspects such as global warming potential| ozone depletion potential| recycling loss and toxicity are discussed. Insulation characteristics of gas mixtures such as c-C4F8/N-2| c-C4F8/air| and c-C4F8/CO2 are examined experimentally under a quasi-homogeneous or an inhomogeneous electric field condition. Most of the characteristics are compared with those of SF6/N-2| which is now widely studied as the most plausible alternative to pure SF6 for gas insulation. The experimental results| together with the discussion| suggest that gas mixtures containing c-C4F8 are possible substitutes for SF6 and SF6/N2. 5618,2001,2,4,Archeological evidence of Pacific salmon distribution in northern Japan and implications for future global warming,Archeological evidence of Pacific salmon in Hokkaido is reviewed and compared with results from western North America. Salmon remains have been found at 24 sites in Hokkaido from the Early Jomon Period to the Ainu Period (6000-100 years ago). Fish remains at three archeological sites in the Kushiro River basin indicated that Pacific salmon (Oncorhynchus spp.) were distributed and utilized from 6000 years ago. The present Kushiro Wetland was formerly covered with seawater and called the Paleo Kushiro Bay 5000-6000 years ago. Based on the molluscan fossil fauna| seawater temperature at Paleo Kushiro Bay was about 5 degreesC warmer than at present. Warmer conditions for salmon in Kushiro 5000-6000 years ago corresponded with the poor conditions for salmon in the Columbia River basin 6000-7000 years ago. If the future global warming is similar to the conditions that prevailed 5000-6000 years ago| the southern limit of salmon distribution will shift northwards and the salmon production will decrease. However| they will not disappear from either Hokkaido or southwestern North America. (C) 2001 Elsevier Science Ltd. All rights reserved. 3020,2001,2,4,Arctic sea ice thickness remained constant during the 1990s,The ice cover of the Arctic Ocean is considered to be a sensitive indicator of global climate change. Recent research| using submarine-based observations| suggests that the Arctic ice cover was thinner in the 1990s compared to an earlier period (1958-1979)| and that it continued to decrease in thickness in the 1990s. Here I analyze subsurface ice thickness (draft) of Arctic sea ice from six submarine cruises from 1991 to 1997. This extensive data set shows that there was no trend towards a thinning ice cover during the 1990s. Data from the North Pole shows a slight increase in mean ice thickness| whereas the Beaufort Sea shows a small decrease| none of which are significant. Transects between the two areas from 76 degrees N to 90 degrees N also show near constant ice thicknesses| with a general spatial decrease from the Pole towards the Beaufort Sea. Combining the present results with those of an earlier study| I conclude that the mean ice thickness has remained on a near-constant level around the North Pole from 1986 to 1997. 3010,2001,2,3,Are Phragmites-dominated wetlands a net source or net sink of greenhouse gases?,Phragmites australis wetlands act as a sink for greenhouse gases by photosynthetic assimilation of carbon dioxide (CO2) from the atmosphere and sequestration of the organic matter produced in the wetland soil. The wetlands also act as a source for greenhouse gases by emission of sediment-produced methane (CH4) to the atmosphere. In P. australis wetlands| the dominant mechanism of CH4 release to the atmosphere is internal gas transport in the plants| primarily by pressurized convective gas flow. The time periods of carbon fixation and CH4 release therefore vary seasonally and diurnally. The balance between net CO2-assimilation and CH4 emission determines if a wetland can be regarded as a net sink or a net source of greenhouse gases| and hence| the function of the wetland in relation to global climate change. On an annual basis up to 15% of the net carbon fixed by the wetlands may be released to the atmosphere as CH4. Because of the different infrared absorption characteristics and atmospheric longevity of CH4 and CO2| the warming effect of CH4 in the atmosphere is about 21 times higher on a mass basis than CO2 over a 100-year timescale. Thus| the immediate carbon balance| coupled with the different physical characteristics of the two gases| would suggest that although some wetlands function as a net sink for CO. the wetlands still increase the greenhouse effect because of their release of CH4. However| the short adjustment time for CH4 in the atmosphere means that| over a longer time scale| the radiative forcing of CH4 is less relative to CO2 and the wetlands effectively become a sink for greenhouse gases. Wetlands may therefore be regarded as a source for greenhouse gases and so increase radiative forcing if evaluated on a short time scale (decades)| but as a sink for greenhouse gases and thus attenuating radiative forcing if evaluated over longer time scales (>100 years). (C) 2001 Elsevier Science B.V. All rights reserved. 3051,2001,4,4,Assimilation of satellite altimetry into a western North Pacific operational model,An ocean data assimilation system| COMPASS-K (the Comprehensive Ocean Modeling| Prediction| Analysis and Synthesis System in the Kuroshio-region)| has been developed at the Meteorological Research Institute (MRI). The purposes of the development are understanding ocean variability in the Kuroshio region as a local response to a global climate change with assimilated four-dimensional data sets| development of an operational system in the Japan Meteorological Agency| and for the GODAE (Global Ocean Data Assimilation Experiment) project. The model is an eddy permitting version of an MRI-OGCM. Space-time decorrelation scales of ocean variability are estimated with TOPEX / POSEIDON (T/P) altimeter data. Subsurface temperature and salinity fields are projected from the T / P altimeter data with a statistical correlation method and are assimilated into the model with a time-retrospective nudging scheme. Seasonal variation in the western North Pacific is investigated. Realistic space-time distribution of the physical quantities| the path of Kuroshio and its separation from Honshu are captured well. The Kuroshio volume transport is well reproduced in a reanalysis experiment of 1993. Preliminary predictability experiments are done in February and March| 1994. Predictability diagram shows the time scale of the predictability for temperature field is about 17 days in the Kuroshio south of Japan. This time scale is smaller than that in the North Atlantic. 5414,2001,2,3,Atlantic thermohaline circulation and its response to increasing CO2 in a coupled atmosphere-ocean model,We discuss aspects of the Atlantic thermohaline circulation (THC) and its response to increased greenhouse gas concentration| using a coupled atmosphere-ocean general circulation model (AOGCM) whose oceanic component is a now hybrid-isopycnal model. Two 200-year model integrations are carried out - a control run assuming fixed atmospheric composition and a perturbation run assuming gradual doubling of CO2. We employ no flux corrections at the air-sea interface| nor do we spin up the ocean prior to coupling. The surface conditions in the control run stabilize after several decades. When doubling CO2 at the rate of 1% per year| the model responds with a 2 degreesC increase in global mean surface air temperature (SAT) after 200 years and a virtually unchanged Atlantic meridional overturning circulation. The latter is maintained by a salinity increase that counteracts the effect of global warming on the surface buoyancy. 5507,2001,4,4,Atmospheric absorption of near infrared and visible solar radiation by the hydrogen bonded water dimer,Based on the physico-chemical properties of water dimers| their near infrared and visible absorption of solar radiation in the earth's atmosphere is calculated. The calculation uses equilibrium constants determined by statistical mechanics| and a vibrational absorption spectrum determined by a coupled oscillator quantum mechanics model and ab initio quantum chemistry. The resulting total atmospheric absorption was calculated using a line-by-line radiative-transfer model| and depends significantly on the dimer abundance| as well as on the frequency and line width given to vibrational transitions. The best estimate achieved for the possible range of total absorption from 400 nm to 5000 run by water dimer in the tropics is 1.6-3.3 W m(-2). In a global-warming scenario| the increased temperature and water vapour partial pressure result in a nonlinear increase in the absorption of solar radiation by water clusters. Most of the energy from water dimer absorption is deposited in the lower troposphere| particularly in the tropics| tending to make it more convective. 5482,2001,3,4,Atmospheric degradation and global warming potentials of three perfluoroalkenes,The vapour phase reactions of perfluoropropene| CF3 - CF = CF2| and perfluorobuta-1|3-diene| CF2=CF-CF=CF2| with OH| NO3 and O-3 were studied at 298 +/- 4K and 740 +/- 5 Torr using long-path FT-IR detection. The reactions with ozone are very slow| k(CF3CFCF2+O3) =(6.2 +/- 1.5) x 10(-22) and k(CF2CFCFCF2+O3) = (6.5 +/- 0.2) x 10(-21) cm(3) Molecules(-1) s(-1)| and upper limits of 3 x 10(-15) cm(3) molecules(-1) s(-1) are reported for the NO3 reaction rate coefficients. The OH reaction rate coefficients were determined as k(CF3CFCF2+OH) = (2.6 +/- 0.7) x 10(-12) and k(CF2CFCFCF2+OH) = (1.1 +/- 0.3) x 10(-11) cm(3) molecules(-1) s(-1); perfluoropropene gave a nearly quantitative yield of CF3CFO and CF2O as organic products| while perfluorobuta-1|3-diene gave from 130% to 170% of CF2O. A chemistry transport model was applied to calculate the atmospheric distributions and lifetimes of the perfluoroalkenes; the global and yearly averaged lifetimes were calculated as 1.9 day for C2F4 and C4F6 and 6 days for C3F6. Quantitative infrared cross-sections of perfluoroethene| perfluoropropene| and perfluorobuta-1|3-diene have been obtained at 298 K in the region 100-2600 cm(-1). Radiative forcing calculations have been performed for these gases assuming either constant vertical profiles or the distribution derived from the chemistry transport model. The results show that the Global Warming Potentials are totally negligible for these compounds. (C) 2001 Elsevier Science Ltd. All rights reserved. 5512,2001,2,4,Atmospheric methyl iodide: High correlation with surface seawater temperature and its implications on the sea-to-air flux,Intensive measurements of atmospheric methyl iodide taken at high| middle| and low latitudes over a period of 3 years have provided evidence for its photochemical production in seawater and given new information that sea-to-air transport of CH3I is mainly controlled by surface seawater temperature (SST). These findings suggest a highly localized production and distribution of CH3I in the surface microlayer. As a result| the oceanic emission of CH|I is likely to be larger than previous estimates based on the classical two-layer model. Owing to the SST dependence of atmospheric CH3I concentration| its impact on tropospheric or stratospheric ozone depletion would be increased by El Nine or future global warming. 5496,2001,4,3,Background monitoring and long-range transport of atmospheric CFC-11 and CFC-12 at Kosan| Korea,The background concentrations of atmospheric CFC-11 and CFC-12 were monitored to assess their impact on stratospheric ozone depletion and global warming from September 1995 to March 1999 at Kosan| Korea| located at eastern margin of the Asian Continent. The concentrations of atmospheric CFC-11 at Kosan have decreased slightly| at a rate of -2.5 pptv yr(-1)| over the period in response to the Montreal Protocol. The CFC-12 mixing ratio at Kosan continues to increase in the atmosphere at a rate of 5.7 pptv yr(-)1 despite international regulations| because of its extreme atmosphere persistence. Recent trends of these two chlorofluorocarbons at Kosan| Korea were concordant with those of the northern hemispheric background monitored unit at Mauna Loa| Hawaii. The maximum seasonal mean mixing ratios of CFC-11 and CFC-12 at Kosan| Korea| were 270 +/-4 pptv in the spring and 538 +/-9 pptv in the winter| and the corresponding seasonal minima were 267 +/-7 and 529 +/- 12 pptv. This occurred in the summer and was due to southeasterly winds from the northwestern Pacific Ocean. By performing a three-day isentropic backward trajectory analysis| it was shown that air masses at Kosan| and with the exception of summer| mainly originated from central and northern China. In particular| the mixing ratios of these two contaminant species are closely related with their air mass trajectories. 5570,2001,4,3,Biogeophysical versus biogeochemical feedbacks of large-scale land cover change,Large-scale changes in land cover affect nearsurface energy| moisture and momentum fluxes owing to changes in surface structure (referred to as biogeophysical effects) and the atmospheric CO2 concentration owing to changes in biomass (biogeochemical effects). Here we quantify the relative magnitude of these processes as well as their synergisms by using a coupled atmosphere-biosphere-ocean model of intermediate complexity. Our sensitivity studies show that tropical deforestation tends to warm the planet because the increase in atmospheric CO2 and hence| atmospheric radiation| outweighs the biogeophysical effects. In mid and high northern latitudes| however| biogeophysical processes| mainly the snow-vegetation-albedo feedback through its synergism with the sea-ice-albedo feedback| win over biogeochemical processes| thereby eventually leading to a global cooling in the case of deforestation and to a global warming| in the case of afforestation. 5524,2001,2,4,Bird migration: a novel theory for the evolution| the control and the adaptability of bird migration,The migratory behaviour of many bird species is currently changing| evidently in connection with global warming; in general there is a shift towards sedentariness. Because experimental studies indicate that all crucial aspects of migration are under direct genetic control| it is unlikely that the observed changes result from phenotypic plasticity. Equally improbable is the assumption of more numerous mutations in the same direction. Instead| the cause may well be rapid processes of selection and microevolution| which are demonstrable in the field and experimentally reproducible. An ideal initial situation for selection processes is partial migration. Such birds' genetic predisposition for both migration and nonmigration amounts to a kind of turntable| from which migrants| residents and partial migrants with various proportions of migratory and nonmigratory individuals can be selected. Partial migration is not only the most common Life form among birds| but is a widespread type of behaviour that developed early in the evolution of plants and animals. The new bird migration theory postulates that birds either evolved partial migration very early or inherited it from avian ancestors| like other characteristics of migration such as compasses and fat deposition. In any case| birds thus possess a fundamental control mechanism which| depending on the environmental situation| permits the rapid emergence of phenotypic migrants or residents or transitional mixed populations comprising various combinations of migrant and resident individuals. This simple new theory allows us to dispense with the previous concept that migratory birds arose polyphyletically from nonmigrants by mutational "behavioural jumps"-a concept that cannot explain| for instance| the currently increased shift away from migratory behaviour. 5497,2001,2,4,Bleaching and recovery of five eastern Pacific corals in an El Nino-related temperature experiment,Coral bleaching events have increased in frequency and severity| due mainly to elevated water temperature associated with El Nino-related warming and a general global warming trend. We experimentally tested the effects of El Nino-like sea temperature conditions on five reef-building corals in the Gulf of Panama. Branching species (Pocillopora damicornis and Pocillopora elegans) and massive species (Porites lobata| Pavona clavus and Pavona gigantea) were exposed to experimentally elevated seawater temperature| similar to1-2 degreesC above ambient| Differences in zooxanthellate coral responses to bleaching and ability to recover were compared and quantified. All corals exposed to high temperature treatment exhibited significant declines in zooxanthellae densities and chlorophyll a concentrations. Pocilloporid species were the most sensitive| being the first to bleach| and suffered the highest mortality (50% after 50 d exposure). Massive coral species demonstrated varying tolerances| but were generally less affected. R gigantea exhibited the greatest resistance to bleaching| with no lethal effects observed. Maximum experimental recovery was observed in R lobata. No signs of recovery occurred in P clavus| as zooxanthellae densities and chlorophyll a concentrations continued to decline under ambient (control) conditions. Experimental coral responses from populations in an upwelling environment are contrasted with field responses observed in a nonupwelling area during the 1997-98 El Nino-Southern Oscillation event. 5623,2001,5,4,C-14 dating of peat and delta O-18-delta D in ground ice from northwest Siberia,We present new radiocarbon dates from a number of Holocene peat deposits along a north-south transect across the Yamal Peninsula. The samples were collected from frozen peat deposits with large ice wedges in: the northern tundra near Seyaha Settlement| in the Central Yamal Peninsula| the southern tundra in Shchuch'ya River valley at the Edem'yaha mouth| the southern part of the Yamal Peninsula| and the southern forest tundra near Labytnangi Town. C-14 dates of wood remains from the tundra in the Yamal Peninsula could be used to reconstruct a northern limit of forest during the Holocene Optimum. The wood layers at the bottom of the peat give evidence for immigration of trees further north beyond the present boundary. The first forest appearance in the Seyaha River valley area is dated about 9 ka BP according to the oldest peat date in the Seyaha cross section. This suggests that summer temperatures were higher than at present. Very fast accumulation of peat (around 5 m/ka: about 9-8 ka BP at Seyaha and about 7-6 ka BP at Shchuch'ya) also supports this observation. In contrast| oxygen isotope composition of Holocene syngenetic ice wedges from the area (delta(18)O= -19.1 to -20.3parts per thousand in the Seyaha cross-section and -17.3 to -20.3parts per thousand in the Shchuch'ya River) show that winter temperatures were significantly lower than presently| i.e. the climate during the Holocene Optimum was slightly more continental. The frozen peat near Labytnangi has thawed during the last 20 years| indicating global warming. 5388,2001,3,3,Carbon sequestration and land management under uncertainty,Uncertainty about the role of forestry and land-use change in mitigating global warming is addressed using a possibilistic linear programming model of forest and agricultural land management. The objective is to maximize the cumulative net discounted returns in the two sectors| while meeting specific carbon-uptake goals and maintaining stable flows of timber over the planning horizon. Because of ambiguity related to timber yield and carbon parameters| and vagueness of policy targets (economic returns| timber production and carbon-uptake)| ordinal measures of uncertainty are applied. While ordinality entails loss of precision| it makes it possible to solve complex problems. This paper compares land-use policies in the boreal forest zone of Northeastern British Columbia under uncertainty with those from a more typical scenario that applies best-guess parameter values. Including uncertainty explicitly into the possibility analysis changes optimal land-use and forest management| and leads to different levels of projected timber supply| economic performance and carbon sequestration. The amount of carbon dioxide (CO2) removed from the atmosphere and the economic cost of carbon uptake are sensitive to how the decision-maker tackles uncertainty. (C) 2001 Elsevier Science B.V. All rights reserved. 2986,2001,3,4,Carbon sequestration: An option for mitigating global climate change,Most people understand the term "carbon sequestration" to mean the uptake of CO2 by trees and other plants through photosynthesis and their storing it as carbon for relatively short time periods. Another form of sequestration -- injecting CO2 into partially depleted oil reservoirs -- is already underway to enhance oil production. CO2 could also be injected into unmineable coal seams| thus enhancing the recovery of the coal-bed methane.
5392,2001,3,2,Carbon stock assessment of two agroforestry systems in a tropical forest reserve in the Philippines,Carbon dioxide is the most abundant greenhouse gas (GHG) that causes global warming. Thus| land uses such as an agroforestry system have a significant role in moderating climate change since they can be sources and sinks of carbon. The aim of the study was to generate data on the carbon stocks of two agroforestry systems| specifically a Gmelina arborea-Theobroma cacao multistorey system and an alley cropping system with Gliricidia sepium hedges at the agroforestry research and demonstration area inside a forest reserve in Southern Luzon| Philippines. The multistorey system had a mean biomass of 258 Mg C ha(-1) and a carbon density of 185 Mg C ha(-1). Carbon was stored in the various pools in the following order of magnitude: soil > tree biomass (above-ground) > necromass > understorey vegetation > roots. The Gliricidia hedgerow had a biomass density of 3.8 Mg C ha(-1); total carbon density was 93 Mg C ha(-1)| of which 92 Mg C ha(-1) was in the soil. 5490,2001,3,4,Carbon stock| afforestation and acidic deposition: An analysis of inter-relation with reference to arid areas,Recent advances in desert afforestation underlines its viability and importance in combating global warming and acidification. In this paper| the inter-relation between afforestation| global warming and acid rain has been analyzed. Numerical simulations indicate that afforestation of deserts has distinct advantage as carbon sink and as an important factor for changing microclimate of the region rather than a source of energy. Acidic deposition may well be utilised as fertiliser in nutrient deficit soil of tropical arid areas. However| past trends and projections of acidic deposition in arid areas adjacent to Thar deserts indicate an early efforts are required to cap the opportunity. Delays may contribute towards more incidences of failures. 5515,2001,2,4,Causes and extent of declines among native North American invertebrate pollinators: Detection| evidence| and consequences,Ecosystem health and agricultural wealth in North America depend on a particular invertebrate fauna to deliver pollination services. Extensive losses in pollinator guilds and communities can disrupt ecosystem integrity| a circumstance that today forces most farmers to rely on honey bees for much fruit and seed production. Are North America's invertebrate pollinator faunas already widely diminished or currently threatened by human activities? How would we know| what are the spatiotemporal scales for detection| and which anthropogenic factors are responsible? Answers to these questions were considered by participants in a workshop sponsored by the National Center for Ecological Analysis and Synthesis in October of 1999| and these questions form the nucleus for the papers in this special issue. Several contributors critically interpret the evidence for declines of bee and fly pollinators| the pollination deficits that should ensue| and their economic costs. Spatiotemporal unruliness in pollinator numbers| particularly bees| is shown to hinder our current insights| highlighting the need for refined survey and sampling designs. At the same time| two remarkable studies clearly show the long-term persistence of members of complex bee communities. Other authors offer new perspectives on habitat fragmentation and global warming as drivers of pollinator declines. Bees and lepidopterans are contrasted in terms of their natural genetic variation and their consequent resilience in the face of population declines. Overall| many ecologists and conservation biologists have not fully appreciated the daunting challenges that accompany sampling designs| taxonomy| and the natural history of bees| flies| and other invertebrate pollinators| a circumstance that must be remedied if we are to reliably monitor invertebrate pollinator populations and respond to their declines with effective conservation measures. 5519,2001,5,4,Central European vegetation response to abrupt climate change at 8.2 ka,Oxygen isotope records show a major climatic reversal at 8.2 ka in Greenland and Europe. Annually laminated sediments from two lakes in Switzerland and Germany were sampled contiguously to assess the response of European vegetation to climate change ca| 8.2 ka with time resolution and precision comparable to those of the Greenland ice cores. The pollen assemblages show pronounced and immediate responses (0-20 yr) of terrestrial vegetation to the climatic change at 8.2 ka. A sudden collapse of Corylus avellana (hazel) was accompanied by the rapid expansion of Pinus (pine)| Betula (birch)| and Tilia (linden)| and by the invasion of Fagus silvatica (beech) and Abies alba (fir)| Vegetational changes suggest that climatic cooling reduced drought stress| allowing more drought-sensitive and taller growing species to out-compete Corylus avellana by forming denser forest canopies| Climate cooling at 8.2 ka and the immediate reorganization of terrestrial ecosystems has gone unrecognized by previous pollen studies. On the basis of our data we conclude that the early Holocene high abundance of C. avellana in Europe was climatically caused| and we question the conventional opinion that postglacial expansions of F| silvatica and A. alba were controlled by low migration rates rather than by climate. The close connection between climatic change and vegetational response at a subcontinental scale implies that forecasted global warming may trigger rapid collapses| expansions| and invasions of tree species. 5575,2001,3,3,Ceramic fuel cells to replace metal burners,Global warming is thought to result from emissions largely caused by combustion reactions. Designs of burners and specifications of their materials are therefore of primary importance in restraining the warming phenomena. This paper proposes a new type of ceramic burner which incorporates many of the innovations which are needed to improve burner performance| including catalytic combustion| premixed fuel/air| recuperation of combustion heat| recycling of reaction products| electric-ignition and electron extraction. The key problems of fuel variation and thermal shock resistance of the ceramic are addressed through the concept of 'reaction gradient' in which the rich sequence of oxidation reactions during combustion is spread through three extended catalytic regimes along the isothermal ceramic device. It is evident that ceramic burners are necessary to provide catalytic activity and to promote electron transfer. The conclusion is that ceramic will ultimately replace metal in burners requiring low emissions and high exergy output. (C) 2001 Kluwer Academic Publishers. 5599,2001,4,3,CFD modelling and experimental investigation of an ejector refrigeration system using methanol as the working fluid,This paper presents results of computational fluid dynamic (CFD) analysis and experimental investigation of an ejector refrigeration system using methanol as the working fluid. The CFD modelling was used to investigate the effect of the relative position of the primary nozzle exit within the mixing chamber on the performance of the ejector. The results of the CFD were used to obtain the optimum geometry of the ejector| which was then used to design| construct and test a small-scale experimental ejector refrigeration system. Methanol was used as the working fluid| as it has the advantage of being an 'environmentally friendly' refrigerant that does not contribute to global warming and ozone layer depletion. In addition| use of methanol allows the ejector refrigeration system to produce cooling at temperatures below the freezing point of the water| which of course would not be possible with a water ejector refrigeration system. CFD results showed that positioning the nozzle exit at least 0.21 length of the mixing chamber throat's diameter upstream of the entrance of the mixing chamber gave better performance than pushing it into the mixing chamber. Experimental values of coefficient of performance (COP) between 0.2 and 0.4 were obtained at operating conditions achievable using low-grade heat such as solar energy and waste heat. Copyright (C) 2001 John Wiley & Sons| Ltd. 5620,2001,3,4,Challenges in developing environmentally safe heat pumping systems,The advent of the global warming crisis has brought about a viewpoint| in many governments| that the halogen family of refrigerants should be replaced| in part or in toto| by the so-called natural refrigerants| For this proposal to be valid it is necessary to consider both the refrigerant's direct environmental impact and its life-long performance under field conditions. This is particularly true in the case of global warming because| for most applications| it is the heat pump's operating efficiency and its impact on the central power plant's emissions that is the dominating environmental factor. Any refrigerant must also meet a variety of other criteria that deal with durability| safety and costs. A simple comparison of basic fluid properties is conducted to indicate what system design considerations must be made if a refrigerant is to become an acceptable alternative. It is also reasoned that while computer models and laboratory prototypes are a necessary beginning| they are not sufficient to determine the true environmental impact of any system. Finally| the question is raised as to whether the refrigerant specification approach is the better path to an improved environment or if it is wiser to leave all options open for researchers and manufacturers to meet an environmental performance standard any way they choose. 5391,2001,5,4,Change of fire frequency in the eastern Canadian boreal forests during the Holocene: does vegetation composition or climate trigger the fire regime?,1 Studies on the variability of natural fire regimes are needed to understand plant responses in a changing environment. Since vegetation changes might follow or trigger changes in fire frequency| climate models suggest that changes in water balance will accompany current global warming| and the response of fire regimes to Holocene hydro-climate changes and vegetation switches may thus serve as a useful analogue for current change. 2 We present high-resolution charcoal records from laminated cores from three small kettle lakes located in mixed-boreal and coniferous-boreal forest. Comparison with some pollen diagrams from the lakes is used to evaluate the role of the local vegetation in the fire history. Fire frequency was reconstructed by measuring the separation of peaks after detrending the charcoal accumulation rate from any background. 3 Several distinct periods of fire regime were detected with fire intervals. Between c. 7000-3000 cal. year BP| fire intervals were double those in the last 2000 years. Fire frequency changed 1000 years earlier in the coniferous-boreal forest than in the mixed-boreal forest to the south. The absence of changes in combustibility species in the pollen data that could explain the fire frequency transition suggests that the vegetation does not control the long-term fire regime in the boreal forest. 4 Climate appears to be the main process triggering fire. The increased frequency may be the result of more frequent drought due to the increasing influence of cool dry westerly Pacific air-masses from mid to late Holocene| and thus of conditions conducive to ignition and fire spread. In east Canada| this change matches other long-term climate proxies and suggests that a switch in atmospheric circulation 2-3000 years ago triggered a less stable climate with more dry summers. Future warming is moreover likely to reduce fire frequency. 3037,2001,4,4,Changes in daily and nightly day-to-day temperature variability during the twentieth century for two stations in Switzerland,An analysis of day-to-day variability was performed on two century-longs daily minimum and maximum temperature series from Switzerland. Warmer temperatures during the 20(th) century have been accompanied by a reduction in day-to-day variability| particularly for minimum temperatures and for winter. There is a significant negative correlation between day-to-day variability and the skewness of the temperature distribution| particularly in winter and for minimum temperatures. Lower variability is linked to a reduced number of cold days and nights. Higher NAO index values tend to be associated not only with warmer temperatures but also with lower day-to-day variability. This paper confirms that the temperature warming during the 20(th) century has happened mainly through the loss of the coldest part of the series| not only in the 24-hour or yearly cycle| but also through the loss of the coldest episodes in each month. 5572,2001,2,4,Changes in the onset of spring in the western United States,Fluctuations in spring climate in the western United States over the last 4-5 decades are described by examining changes in the blooming of plants and the timing of snowmelt-runoff pulses. The two measures of spring's onset that are employed are the timing of first bloom of lilac and honeysuckle bushes from a long-term cooperative phenological network| and the timing of the first major pulse of snowmelt recorded from high-elevation streams. Both measures contain year-to-year fluctuations| with typical year-to year fluctuations at a given site of one to three weeks. These fluctuations are spatially coherent| forming regional patterns that cover most of the west. Fluctuations in lilac first bloom dates are highly correlated to those of honeysuckle| and both are significantly correlated with those of the spring snowmelt pulse. Each of these measures| then| probably respond to a common mechanism. Various analyses indicate that anomalous temperature exerts the greatest influence upon both interannual and secular changes in the onset of spring in these networks. Earlier spring onsets since the late 1970s are a remarkable feature of the records| and reflect the unusual spell of warmer-than-normal springs in western North America during this period. The warm episodes are clearly related to larger-scale atmospheric conditions across North America and the North Pacific| but whether this is predominantly an expression of natural variability or also a symptom of global warming is not certain. 5582,2001,3,3,Characteristics and performance of a deep-ocean disposal system for low-purity CO2 gas via gas lift effect,Ocean sequestration of CO2 is a hopeful option to solve the global warming problems. We proposed the Gas Lift Advanced Dissolution (GLAD) System for efficient sequestration of pure CO2 at deep sea. The GLAD system is an inverse-J pipeline set in the ocean between 200 and 3000 m in depth. We have recently improved it to treat low-purity CO2 gas to reduce the cost for separation and capture of CO2 from exhausted gas. The newly developed system| named the Progressive Gas Lift Advanced Dissolution (P-GLAD) System| is to dissolve low-purity CO2 bubbles into seawater at a depth of 200-300 m and at the same time sequestrate CO2 at the deep sea of 1000-3000 m. Previous ideas of deep-sea sequestration of CO2| including storage of liquid CO2 on the deep-sea floor and direct releasing of liquid CO2 into the deep sea| necessitate the consumption of a huge amount of energy| because the realization of these ideas requires both high-purity capture of CO2 from exhausted gas and liquefaction of the CO2. To realize deep-sea sequestration of CO2 with low energy consumption and low environmental impact| we utilize a gas-lift effect to simultaneously dissolve low-purity CO2 gas into shallow seawater and transport the CO2 solution to a great depth. The present paper describes basic characteristics and performance of the P-GLAD system for low-purity CO2 gases| experimentally and numerically. It is demonstrated that the system has satisfactory ability to both dissolve CO2 gas and pump the CO2 solution. To confirm economic feasibility of the P-GLAD System| we also discuss the overall cost estimation including an additional system for CO2 capturing as well as the construction of P-GLAD. The cost for the P-GLAD is estimated to be half of those for previous ideas. 5503,2001,3,4,Characterization of iodoheptafluoropropane as a dielectric etchant. III. Effluent analysis,The work presented in this article represents the third and final part of a series of articles which present a systematic evaluation of iodoheptafluoropropane (C3F7I) as a potential replacement for perfluorocompound chemistries in dielectric etch applications. In the experiments discussed in this series| 1- and 2-iodoheptafluoropropane based etch processes had been employed in a via etch application in an inductively coupled high density plasma etch tool. Part I of this article discusses etch process behavior of 1- and 2-iodoheptafluoropropane| while Part Il examines films deposited by the I-iodo isomer. This article will focus on the composition of the process effluent stream| as characterized by Fourier transform infrared (FTIR) spectroscopy. Data generated by both isomers of the compound will be presented and compared to those generated by conventional (C3F8- and C2F6-based) etch processes. Significant reductions in global warming emission (on the order of 80%-85%) were obtained relative to the conventional processes. Additionally| FTIR data were correlated with process and film analysis data presented in Parts I and II to generate better understanding of key plasma mechanisms in iodofluorocarbon etch environments. (C) 2001 American Vacuum Society. 5565,2001,4,4,Chinese life cycle impact assessments factors,The methodological basis and procedures for determination of Chinese normalization references and weighting factors according to the EDIP-method is described. According to Chinese industrial development intensity and population density| China was divided into three regions and the normalization references for each region were calculated on the basis of an inventory of all of the region's environmental emissions in 1990. The normalization reference was determined as the total environmental impact potential for the area in question in 1990(EP(j)(90)) divided by the population. The weighting factor was determined as the normalization reference (ER ( j)90) divided by society's target contribution in the year 2000 abased on Chinese political reduction plans| ER ( j)(T2000). This paper presents and discuss results obtained for eight different environmental impact categories relevant for China: global warming| stratospheric ozone depletion| acidification| nutrient enrichment| photochemical ozone formation and generation of bulk waste| hazardous waste and slag and ashes. 3029,2001,5,4,Climate analysis of endemic species - A novel method for quantitative analysis of global climate change since tertiary,There are many extant endemic plants in China| which were widely distributed in the North Hemisphere during Tertiary. The global cooling during the Tertiary caused a series of narrow distribution regions of the plants. Quaternary glaciation invaded most regions of North America and Eurasia where severe destruction was imposed onto vegetation. However| such destruction was lessened in China largely because of specific topographic and geographical and obviously| a number of other conditions accounted for an unusual refugee camp for the relies of plants in China| among which lots of endemic taxa exist. Recently| Chinese endemic species| such as Metaseqouia| Eucommia| have been employed to conduct multi-disciplinary comprehensive studies so as to analyze Tertiary climate changes quantitatively. Meanwhile| a rigorous method| i.e. climate analysis of endemic species (CAES) has come to maturation. This method is characteristic of some generality because it is supposed to be applicable to the endemic species in other regions of the world. CAES is involved in the following aspects: 1. Conduct multidisciplinary studies on living and fossil species of endemic plants and trace their evolutionary courses. 2. Compare fossil species with living one and clarify which is the nearest living relative (NLR) to fossil counterpart. 3. Fossils and their living counterparts (NLR) are supposed to have similar ecological requirements to meet their life cycles. 4. Investigate the geographic distribution of living and fossil plants within the same taxa and ascertain the dynamic changes of their distributions in geological age. 5. Analyze climate factors in the distribution of specific endemic taxa and obtain the data of climatic characters which are suitable for reconstruction of paleoclimate where fossil counterparts lived. 6. Further study the physio-ecology of living species and determinate paleoclimate where fossil counterparts lived. 7. Integrate analysis of the data from steps 4| 5 and 6| and quantitatively reconstruct the climate where fossil and living plants survive. 5551,2001,4,3,Climate and ozone response to increased stratospheric water vapor,Stratospheric water vapor abundance affects ozone| surface climate| and stratospheric temperatures. From 30-50 km altitude| temperatures show global decreases of 3-6 It over recent decades. These may be a proxy for water vapor increases| as the GISS climate model reproduces these trends only when stratospheric water vapor is allowed to increase. Observations suggest that stratospheric water vapor is indeed increasing| though measurements are extremely limited in either spatial coverage or duration. Model results suggest that the observed changes may be part of a global| long-term trend. Furthermore| the required water vapor change cannot be accounted for by increased stratospheric production| suggesting that climate change may be altering tropospheric input. The calculated water vapor increase contributes an additional approximate to 24% (approximate to0.2 W/m(2)) to the global warming from well-mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues| it could increase future global warming and impede stratospheric ozone recovery. 5455,2001,4,4,Climate change and site: relevant mechanisms and modeling techniques,Forest growth modeling is moving away from description and toward explanation. The acceptance of global warming and effects related to climate change has reinforced this evolution. In the recent past| there have been several reviews of modeling techniques that have addressed| among other things| model structure and hierarchies within models. We argue that models seeking to adequately address climate change must include a specific suite of site characteristics. These range from primary effects of climate change (temperature| CO2| and O-3 increase) to secondary effects (increase in soil temperature| microbial activity| and changes in precipitation patterns) and tertiary effects (changes in tree phenology and photosynthesis). This paper (i) compares 12 existing individual tree growth simulators designed to address climate change or related effects| (ii) proposes a set of site-related mechanisms and entities to be included in any modeling framework to address climate change| and (iii) suggests appropriate lines of research to attain the goal of a model driven by climate and able to be initialized with readily available metrics. (C) 2001 Elsevier Science B.V. All rights reserved. 2975,2001,4,4,Climate change and trend detection in selected rivers within the Asia-Pacific region,Global climate change is currently an issue of great concern. This phenomenon was studied using the runoff of large rivers| which can be considered a regional integrator of the local precipitation occurring in their basins. The long-term stationarity and the possibility of trends in streamflow records stored in the databank of the Global Runoff Data Center (GRDC) at the Federal Institute of Hydrology in Koblenz (Germany) were studied. Runoff records originating from. 78 rivers with long monthly runoff series that are geographically distributed throughout the whole Asia-Pacific region were selected for study. For each of the selected rivers| three time series were constructed and analyzed: the mean yearly| and the maximum and minimum monthly discharges. These series were submitted to a two-tier analysis. First| a segmentation procedure developed by Hubert was applied to assess their stationarity. Then the segmented series were submitted to a specialized trend detection software. The results show that about two-thirds of the series have remained stationary and that the monthly minimum runoff exhibited more changing levels (37/78) than the mean (26/78) and maximum (18/78) runoff. Most of the detected changes occurred during the 1960s and 1970s| a period of rapid demographic expansion and urbanization in Asia| when irrigation and other water uses were developed| especially in tropical areas. During the same period and within the area studied| a number of large dams and reservoirs were completed. Since these anthropic interventions could be at the origin of the changes in runoff| there is no regionally consistent evidence supporting global climate change. 3013,2001,2,4,Climate change effects on vegetation distribution and carbon budget in the United States,The Kyoto protocol has focused the attention of the public and policymarkers on the earth's carbon (C) budget. Previous estimates of the impacts of vegetation change have been limited to equilibrium "snapshots" that could not capture nonlinear or threshold effects along the trajectory of change. New models have been designed to complement equilibrium models and simulate vegetation succession through time while estimating variability in the C budget and responses to episodic events such as drought and fire. In addition| a plethora of future climate scenarios has been used to produce a bewildering variety of simulated ecological responses. Our objectives were to use an equilibrium model (Mapped Atmosphere-Plant-Soil system| or MAPSS) and a dynamic model (MCl) to (a) simulate changes in potential equilibrium-vegetation distribution under historical conditions and across a wide gradient of future temperature changes to look for consistencies and trends among the many future scenarios| (b) simulate time-dependent changes in vegetation distribution and its associated C pools to illustrate the possible trajectories of vegetation change near the high and low ends of the temperature gradient| and (c) analyze the extent of the US area supporting a negative C balance. Both models agree that a moderate increase in temperature produces an increase in vegetation density and carbon sequestration across most of the US with small changes in vegetation types. Large increases in temperature cause losses of C with large shifts in vegetation types. In the western states| particularly southern California| precipitation and thus vegetation density increase and forests expand under all but the hottest scenarios. In the eastern US| particularly the Southeast| forests expand under the more moderate scenarios but decline under more severe climate scenarios| with catastrophic fires potentially causing rapid vegetation conversions from forest to savanna. Both models show that there is a potential for either positive or negative feedbacks to the atmosphere depending on the level of warming in the climate change scenarios. 5608,2001,5,4,Climate changes in northern China since the late Pleistocene and its response to global change,Nine representative high resolution profiles with reliable C-14 chronologies have been chosen from the monsoon sensitive areas in China (winter monsoon from the north-west. and summer monsoon from the east) to provide a comparative picture of climate change within these areas. Comprehensive analyses of stratigraphic sequences and climatic proxy data ha||e been used to reconstruct a history of fluctuating dry and wet environmental conditions in these monsoon sensitive areas since the last deglaciation. These records have also been compared with Greenland ice core and Guliya ice core data. Four major events representing these climate fluctuations (E1-E4) are recognised. Among them| E3 indicates an abrupt cooling event after the Younger Dryas interval. This event has so far only been recognised in China and high latitude areas in the northern hemisphere. It is proposed that century to millenial scale global temperature changes affect the intensity of monsoon circulation through ocean/atmosphere interactions| hence producing dry and wet climate fluctuations in monsoon sensitive areas. In an era of global warming. the overall picture presented by the sequences of wet/dry periods recorded in Chinese monsoon affected areas during the last deglaciation can be used as an historical analogue for future predictions of medium to long term climate change within these areas. (C) 2001 Published by Elsevier Science Ltd. 5661,2001,2,2,Climate model simulations of effects of increased atmospheric CO2 and loss of sea ice on ocean salinity and tracer uptake,Recent observations show a decrease in the extent of Northern Hemisphere sea ice; this decrease has been attributed to human activities. Climate model simulations are presented that examine how loss of sea ice affects the ocean salinity and density structure| and rates of uptake of an idealized transient tracer. The latter results are indicative of how loss of sea ice might affect the ocean's rate of uptake of anthropogenic carbon from the atmosphere. In simulations in which there is no freshwater forcing due to sea ice forming or melting| the salinity minimum associated with Antarctic Intermediate Water is much weaker than in simulations of the present-day ocean. This suggests that this salinity minimum is maintained in part by a steady supply of freshwater from melting of Antarctic sea ice. In addition| in simulations with no freshwater forcing due to sea ice| vertical salinity and density gradients in the Southern and Arctic Oceans are weaker than in simulations of the present-day ocean. This supports the notion that these gradients are maintained in part by freshwater forcing due to the seasonal cycle of formation and melting of sea ice. As a result| loss of sea ice due to global warming would tend to decrease the stability in parts of the ocean; this opposes the well-known tendency of global warming to increase ocean stability by warming and freshening the upper ocean. Simulations of ocean uptake of an idealized transient tracer in both constant-CO2 and increasing-CO2 environments are performed to investigate the effects of physical changes in ocean and sea ice on transient tracer uptake. In the Southern Ocean| physical changes to the ocean and sea ice are found that result in slower transient tracer accumulation in most locations. When averaged over the entire Southern Ocean| however| these reductions are small| because changes in convective activity due to increased atmospheric CO2 are relatively small| and because transient tracer uptake is relatively insensitive to changes in convective activity. These results suggest that Southern Ocean uptake of anthropogenic CO2 may decrease less than previously supposed as global warming progresses. 2992,2001,5,4,Climate-driven range expansion and morphological evolution in a marine gastropod,Little is known about the phenotypic consequences of global climate change| despite the excellent Pleistocene fossil record of many taxa. We used morphological measurements from extant and Pleistocene populations of a marine gastropod (Acanthinucella spirata) in conjunction with mitochondrial DNA sequence variation from Living populations to determine how populations responded phenotypically to Pleistocene climatic changes. Northern populations show Little sequence variation as compared to southern populations| a pattern consistent with a recent northward range expansion. These recently recolonized northern populations also contain shell morphologies that are absent in extant southern populations and throughout the Pleistocene fossil record| Thus| contrary to traditional expectations that morphological evolution should occur Largely within Pleistocene refugia| our data show that geographical range shifts in response to climatic change can Lead to significant morphological evolution. 5566,2001,2,4,Climatic perspectives on Sahelian desiccation: 1973-1998,The African Sahel provides the most dramatic example of multi-decadal climate variability that has been quantitatively and directly measured. Annual rainfall across this region fell by between 20 and 30 per cent between the decades leading up to political independence for the Sahelian nations (1930s to 1950s) and the decades since (1970s to 1990s). Climatic perspectives on the nature and causes of this period of desiccation have changed and| in some cases| matured as the years - and the drought - continued. This paper reviews these changing perspectives and reflects on three central questions: How unique an occurrence has been this desiccation in the recent human history of the Sahel? Can we find an adequate explanation for this desiccation in the natural forces that shape the climate system| or do we have to implicate human interventions in the system? Is our understanding of climate variability sufficient to allow us to develop seasonal rainfall forecasting capabilities for the region? (C) 2001 Elsevier Science Ltd. All rights reserved. 5474,2001,2,4,Climatological thresholds of daily rainfall,This technical note summarizes the results from daily rainfall data analysis with relation to annual rainfall amounts. By investigating the behavior of correlation coefficients between the annual rainfall amounts and the within-the-year cumulative frequency distribution functions of wet days with various threshold rainfall depths| it was found that (1) the annual rainfall amount is weakly correlated with the number of either dry or wet days-thus| the zero rainfall depth is not a proper threshold for the explanation of dry or wet years; and (2) there exist certain thresholds of daily rainfall depth (the climatological thresholds) with which the cumulative frequency of wet days can be well related with the annual rainfall amount. Also with this threshold| the wet and dry years can be seen divided clearly into separate groups of the cumulative frequency distribution functions| without any overlaps| which were common when using the zero rainfall depth as a threshold. Because it is found that there exist certain thresholds to be used for explaining the annual rainfall amount changes| these might also be used effectively for the analysis of possible changes in flood or drought patterns caused by global warming. 5504,2001,4,3,CLIMBER-2: a climate system model of intermediate complexity. Part II: model sensitivity,A set of sensitivity experiments with the climate system model of intermediate complexity CLIMBER-2 was performed to compare its sensitivity to changes in different types of forcings and boundary conditions with the results of comprehensive models (GCMs). We investigated the climate system response to changes in freshwater flux into the Northern Atlantic| CO2 concentration| solar insolation| and vegetation cover in the boreal zone and in the tropics. All these experiments were compared with the results of corresponding experiments performed with different GCMs. Qualitative| and in many respects| quantitative agreement between the results of CLIMBER-2 and GCMs demonstrate the ability of our climate system model of intermediate complexity to address diverse aspects of the climate change problem. In addition| we used our model for a series of experiments to assess the impact of some climate feedbacks and uncertainties in model parameters on the model sensitivity to different forcings. We studied the role of freshwater feedback and vertical ocean diffusivity for the stability properties of the thermohaline ocean circulation. We show that freshwater feedback plays a minor role| while changes of vertical diffusivity in the ocean considerably affect the circulation stability. In global warming experiments we analysed the impact of hydrological sensitivity and vertical diffusivity on the long-term evolution of the thermohaline circulation. In the boreal and tropical deforestation experiments we assessed the role of an interactive ocean and showed that for both types of deforestation scenarios| an interactive ocean leads to an additional cooling due to albedo and water vapour feedbacks. 2999,2001,5,4,Closing of the Indonesian seaway as a precursor to east African aridircation around 3-4 million years ago,Global climate change around 3-4 Myr ago is thought to have influenced the evolution of hominids| via the aridification of Africa| and may have been the precursor to Pleistocene glaciation about 2.75 Myr ago. Most explanations of these climatic events involve changes in circulation of the North Atlantic Ocean due to the closing of the Isthmus of Panama. Here we suggest| instead| that closure of the Indonesian seaway 3-4 Myr ago could be responsible for these climate changes| in particular the aridification of Africa. We use simple theory and results from an ocean circulation model to show that the northward displacement of New Guinea| about 5 Myr ago| may have switched the source of flow through Indonesia-from warm South Pacific to relatively cold North Pacific waters. This would have decreased sea surface temperatures in the Indian Ocean| leading to reduced rainfall over eastern Africa. We further suggest that the changes in the equatorial Pacific may have reduced atmospheric heat transport from the tropics to higher latitudes| stimulating global cooling and the eventual growth of ice sheets. 5489,2001,2,4,CO2 enrichment increases water-use efficiency in sorghum,Sorghum (Sorghum bicolor) was grown for two consecutive seasons at Maricopa| AZ| USA| using the free-air CO| enrichment (FACE) approach to investigate evapotranspiration of this C4 plant at ample and limited water supplies. Crop evapotranspiration (ET) was measured using two CO2 concentrations (control| c. 370 mu mol mol(-1); FACE| ambient +200 mu mol mol(-1)) and two irrigation treatments (well watered and water-limited). Volumetric soil water content was measured before and after each irrigation using neutron scattering techniques. Averaged over both years| elevated CO2 reduced cumulative ET by 10% when plants were given ample water and by 4% under severe drought stress. Water-use efficiency based on grain yield (WUE-G) increased| due to CO2 enrichment| by 9% and 19% in wet and dry plots| respectively; based on total biomass| water-use efficiency (WUE-B) increased by 16% and 17% in wet and dry plots| respectively. These data suggest that in the future high-CO2 environment| water requirements for irrigated sorghum will be lower than at present| while dry-land productivity will increase| provided global warming is minimal. 5604,2001,2,4,Coastal management and sea-level rise,The predicted rise in sea level due to global warming has given rise to much speculation as to the impact on erosion and accretion rates at the coast as well as increases in hazards to coastal users. This paper focuses on the spatial adjustments that coastal landforms will exhibit in response to changing energy gradients both normal to and parallel to the shore. These adjustments| in many cases| will take the form of the migration of landforms in order that they maintain their position within the coastal energy gradient. Prediction of the rates of such migration will be fundamental to the future management of the changing coastal environment. The paper discusses the impact of sea-level rise on the two basic coastal landform assemblages: those in estuaries and those on the open coast| and then goes on to examine the effect on ebb-tidal deltas that are located at the critical junction between estuaries and open coasts. In each case| the rates of landform migration under an accelerated sea-level rise are predicted and compared with existing rates using examples from the east coast of Britain. Assuming a sea-level rise of 6 mm/year| the paper predicts that estuaries will migrate landwards at rates of around 10 m/year| open-coast landforms can exhibit long-shore migration rates of 50 m/year| while ebb-tidal deltas may extend laterally along the shore at rates of 300 m/year. The implication for the management of such dynamic coastal systems| including such issues as coastal defence and conservation| are discussed. (C) 2001 Published by Elsevier Science B.V. 2951,2001,5,4,Coherent patterns of ice-rafted debris deposits in the Nordic regions during the last glacial (10-60 ka),We have synchronized records of ice-rafted rock debris deposits of three sediment cores from the Norwegian Sea and the Irminger Basin during the last glacial period from 10 to 50 ka by combining the use of radiocarbon dates and adjustments of physical properties. Our synchronized records indicate that layers rich in ice-rafted debris were deposited throughout the Nordic regions at times near to synchronous with the major collapses of the Laurentide ice sheet: during the Heinrich events. There are also millennial-scale| coherent and near to synchronous deposits of ice-rafted rock debris into the Norwegian Sea related to repetitive changes of the flux of icebergs from the Fenno-Scandinavian. The correlation with the cold phases of the Dansgaard-Oeschger temperature record points to a close coupling between atmospheric temperature oscillations and variations of iceberg fluxes into the Norwegian Sea during the last glacial. Variations in atmospheric circulation patterns bringing moisture supply to high latitudes and the distribution of this moisture over the different Northern Hemisphere coastal ice sheets and ice shelves could be controlling both the timing of ice sheet advances and the flux of iceberg to the open ocean. (C) 2001 Elsevier Science B.V. All rights reserved. 5434,2001,2,2,Collapse and reorganisation of the Southern Ocean overturning under global warming in a coupled model,This study investigates the long-term behaviour of the thermohaline circulation (THC) in the CSIRO climate model| under a scenario of transient increase of atmospheric (equivalent) CO2 concentration followed by a perpetual stabilisation at triple the initial level (3xCO(2)). The North Atlantic Deep Water Formation (NADWF) declines substantially and the Antarctic Bottom Water Formation (AABWF) essentially ceases by the time Of CO2 tripling. During the subsequent millennium of stable 3xCO(2)| NADWF recovers slightly but the AABWF shows no sign of returning and the residual deep overturning dies away. Accelerating the convergence to equilibrium of the deep ocean under the 3XCO2 condition| the global THC eventually reaches a near-stable state with the entire ocean warming by about 7 degreesC| NADWF fully recovered and AABWF partly re-established. This result shows a possible new quasiequilibrium of the ocean under long-term global warming induced by the anthropogenic CO2 increase. 5545,2001,2,4,Comments on the process and product of the health impacts assessment component of the national assessment of the potential consequences of climate variability and change for the United States,In 1990 Congress formed the U.S. Global Change Research Program and required it to conduct a periodic national assessment of the potential impacts of climate variability and change on all regions and select economic/resource sectors of the United States. Between 1998 and 2000| a team of experts collaborated on a health impacts assessment that formed the basis for the first National Assessment's analysis of the potential impacts of climate on human health. The health impacts assessment was integrated across a number of health disciplines and involved a search for and qualitative expert judgment review of data on the potential links between climate events and population health. Accomplishments included identification of vulnerable populations| adaptation strategies| research needs| and data gaps. Experts| stakeholders| and the public were involved. The assessment is reported in five articles in this issue; a summary was published in the April 2000 issue of Environmental Health Perspectives. The assessment report will enhance understanding of ways human health might be affected by various climate-associated stresses and of the need for further empirical and predictive research. Improved understanding and communication of the significance and inevitability of uncertainties in such an assessment are critical to further research and policy development. 5417,2001,2,4,Community persistence among stream invertebrates tracks the North Atlantic Oscillation,1. The North Atlantic Oscillation (NAO) affects marine ecosystems| lakes and some terrestrial ecosystems around the Atlantic rim| but evidence for effects on rivers is scarce. For 14 years| we sampled riverine macroinvertebrates in eight independent streams from the Llyn Brianne experimental catchments in central Wales. We assessed whether year-to-year persistence in rank abundance and species composition tracked the NAO. 2. Persistence was quasi-cyclical and varied synchronously across all streams| irrespective of chemistry and catchment land use. Invertebrate communities in all stream types or habitats switched significantly from being highly persistent during negative phases of the NAO (winter index <1 = cold| dry winters) to unstable during positive phases (>1 = mild| wet winters). These effects occurred in both rare and common taxa. 3. Acid episodes could not explain low persistence in positive NAO years because variations in acid-base status were not linked to the NAO. Moreover| fluctuations in persistence were apparent even in well-buffered streams. 4. Discharge in adjacent gauged catchments increased in positive NAO years by 15-18% but neither flow variability nor flow maxima were higher. Nor were variations in invertebrate persistence at Llyn Brianne directly correlated with discharge pattern. Discharge variations alone were therefore insufficient to explain links between persistence and the NAO| but we cannot exclude subtle effects due either to flow or temperature. 5. These data illustrate how the persistence of invertebrate communities varies through time in fluctuating environments. Positive phases of the NAO are accompanied by ecological instability in the Llyn Brianne streams| although the exact mechanisms are currently unclear. The effects of the NAO might confound or obscure other long-term change in rivers such as recovery from acidification or the effects of global warming. 5457,2001,2,4,Comparative vessel anatomy of arctic deciduous and evergreen dicots,Arctic tundra plant species exhibit striking variation in leaf character and growth form. Both are likely related to differences in vessel anatomy| and all may affect responses to climate changes in the Arctic. To investigate the relationships among leaf character| growth form| vessel anatomy| and susceptibility to freeze-thaw-induced xylem cavitation| xylem vessel characteristics were compared among six deciduous and six evergreen arctic dicot species of erect and prostrate growth forms. We hypothesized that deciduous and erect species would have larger and longer vessels than evergreen and cushion/mat-forming species. Vessel lengths| diameters| and densities were measured for each species. Theoretical vessel flow rates were calculated using Poiseuille's law for ideal capillaries. Flow rates were used to determine the susceptibility of vessels to cavitation induced by freeze-thaw events that may become more frequent with global warming. Vessel diameters were larger in deciduous species compared to evergreens| and in shrubs/trees vs. cushion/mat-forming plants. Vessel length distributions| however| did not differ for growth form or leaf character. Vessel density was greater in cushion/mat-forming species than in shrub/tree species. Deciduous plants showed a greater contribution to total conductivity by relatively larger vessels than evergreens. One of the deciduous species| Vaccinium uliginosum| is predicted to be susceptible to freeze-thaw-induced cavitation. These results have important implications for future arctic species composition and plant community structure. 5609,2001,3,4,Comparing intensive| extensified and organic grassland farming in southern Germany by process life cycle assessment,To reduce the environmental burden of agriculture| suitable methods to comprehend and assess the impact on natural resources are needed. One of the methods considered is the life cycle assessment (LCA) method| which was used to assess the environmental impacts of 18 grassland farms in three different farming intensities - intensive| extensified| and organic - in the Allgau region in southern Germany. Extensified and organic compared with intensive farms could reduce negative effects in the abiotic impact categories of energy use| global warming potential (GWP) and ground water mainly by renouncing mineral nitrogen fertilizer. Energy consumption of intensive farms was 19.1 GJ ha(-1) and 2.7 GJ t(-1) milk| of extensified and organic farms 8.7 and 5.9 GJ ha(-1) along with 1.3 and 1.2 GJ t(-1) milk| respectively Global warming potential was 9.4| 7.0 and 6.3 CO2-equivalents ha(-1) and 1.3| 1.0 and 1.3 CO2-equivalents t(-1) milk for the intensive| extensified and organic farms| respectively. Acidification calculated in SO2-equivalents was high| but the extensified (119 kg SO2 ha(-1)) and the organic farms (107 kg SO2 ha(-1)) emit a lower amount compared with the intensive farms (136 kg SO2 ha(-1)). Eutrophication potential computed in PO4-equivalents was higher for intensive (54.2 kg PO4 ha(-1)) compared with extensified (31.2 kg PO4 ha(-1)) and organic farms (13.5 kg PO4 ha(-1)). Farmgate balances for N (80.1| 31.4 and 31.1 kg ha(-1)) and P (5.3| 4.5 and -2.3 kg ha(-1)) for intensive| extensified and organic farms| respectively| indicate the different impacts on ground and surface water quality. Analysing the impact categories biodiversity| landscape image and animal husbandry| organic farms had clear advantages in the indicators number of grassland species| grazing cattle| layout of farmstead and herd management| but indices in these categories showed a wide range and are partly independent of the farming system. (C) 2001 Elsevier Science B.V. All rights reserved. 5411,2001,4,3,Comparison of climate change scenarios for Sweden based on statistical and dynamical downscaling of monthly precipitation,Two dynamically and statistically downscaled precipitation scenarios for Sweden are compared with respect to changes in the mean| The dynamically downscaled scenarios are generated by a 44 km version of the Rossby Centre regional climate model (RCM). The RCM is driven by data from 2 global greenhouse gas simulations sharing a 2.6degreesC global warming| one made by the HadCM2 and the other by the ECHAM4 general circulation model (GCM). The statistical downscaling model driven by the same GCMs is regression-based and incorporates large-scale circulation indices of the 2 geostrophic wind components (u and v)| total vorticity (xi) and large-scale humidity at 850 hPa (q850) as predictors. The precipitation climates of the GCMs| RCMs and statistical models from the control runs are compared with respect to their ability to reproduce the observed seasonal cycle. Great improvements in the simulation of the seasonal cycle by all the downscaling models compared to the GCMs significantly increase the credibility of the downscaling models| The precipitation changes produced by the statistical models result from changes in all predictors| but the change in 4 is the greatest contributor in southern Sweden followed by q850 and u| while changes in q850 have greater effects in the northern parts of the country. The temporal and spatial variability of precipitation changes are higher in the statistically downscaled scenarios than in the dynamically downscaled ones. Comparisons of the 4 scenarios show that the spread of the scenarios created by the statistical model is on average larger than that between the RCM scenarios. The relatively large average spread is mainly due to the large differences found in summer. The seasonally averaged difference of the dynamical and statistical scenarios for the ECHAM4-based downscaled scenarios is 12%| and for the HadCM2 downscaled scenarios 21%. The differences in annual precipitation change are smaller| on average 4.5% among the HadCM2-based downscaled scenarios| and 6.9% among the ECHAM4-based downscaling scenarios. 5459,2001,2,4,Competitive interactions between tree species in New Zealand's old-growth indigenous forests,New Zealand's four broad-leaved evergreen tree species from the genus Nothofagus all show pronounced distributional disjunctions| independent of environmental factors known to influence tree distributions. Here| we use these disjunctions as the basis for a natural removal experiment to investigate competitive interactions between Nothofagus and a range of other widespread conifer and broad-leaved tree species. We first model the abundance of non-Nothofagus species as a function of environment| using Generalized Additive Models (GAMs) and an extensive data set sampling much of New Zealand's remaining old-growth forests. We then assess the effects of competitive interaction with Nothofagus by adding statistical terms describing (1) Nothofagus abundance| and (2) interactions between Nothofagus abundance and annual temperature| the dominant environmental gradient. Results indicate substantial reductions in the abundance of many species as Nothofagus abundance increases. The magnitude of this reduction varies with position along the dominant environmental gradient; species overlapping most strongly with Nothofagus are generally most sensitive to increases in Nothofagus abundance. In addition| both the shapes of species responses to mean annual temperature and the positions of their optima change as Nothofagus abundance increases. This demonstration of competition using community compositional data has implications both for vegetation theory and for prediction of the likely impacts of global warming on New Zealand's forest pattern. 5561,2001,3,4,Complex ecologic-economic dynamics and environmental policy,Various complex dynamics in ecologic-economic systems are presented with an emphasis upon models of global warming dynamics and fishery dynamics. Chaotic and catastrophic dynamic patterns are shown to be possible| along with other complex dynamics arising from non-linearities in such combined systems. Problems associated with amplified oscillations due to these non-linear interactions in the combined interactions of human economic decisionmaking with ecological dynamics are identified and discussed. Implications for policy are examined with strong recommendations for greater emphasis| in particular upon the precautionary principle to avoid catastrophic collapses beyond critical thresholds and the Scale-Matching Principle to ensure that efforts to manage complex non-linear dynamics are directed at the appropriate levers of ecologic-economic interaction. (C) 2001 Elsevier Science B.V. All rights reserved. 5521,2001,5,4,Composite surface temperature history from simultaneous inversion of borehole temperatures in western Canadian plains,Functional space inversions (FSI) of precise temperature logs from wells located in low conductivity elastic sediments of the western Canadian Sedimentary Basin show evidence of extensive| recent ground surface temperature (GST) warming. Simultaneous inversion of the data| as well as averaging of the individual site reconstructions| indicate that this high magnitude of GST warming exceeds over two times that of globally averaged GST's [Science 282 (1998) 279] and is significantly higher than that of surface temperature histories based on instrumental records and tree ring reconstruction in northern and western Canada [Holocene 7 (1997) 375; Science 278 (1997) 1251; Clim. Res. 12 (1999) 39]. (C) 2001 Elsevier Science B.V. All rights reserved. 5435,2001,2,4,Constraint to adaptive evolution in response to global warming,We characterized the genetic architecture of three populations of a native North American prairie plant in field conditions that simulate the warmer and more and climates predicted by global climate models. Despite genetic variance for traits under selection| among-trait genetic correlations that are antagonistic to the direction of selection limit adaptive evolution within these populations. Predicted rates of evolutionary response are much slower than the predicted rate of climate change. 3044,2001,5,4,Continuous Late Quaternary proxy climate records from loess in Beringia,Loess deposits in eastern Beringia contain continuous proxy records of the effects of past climatic change on terrestrial landscapes at high latitudes. Variations of environmental magnetism and sedimentology of high-latitude loess deposits indicate that the timing and pattern of responses to local variations in wind intensity| storminess| and pedogenesis in eastern Beringia closely resemble the pattern of global climate change during the Late Quaternary deduced from studies of marine and ice core records. The age of paleoclimatic fluctuations| permafrost features| volcanic ash horizons| buried forest layers and paleosols| and other features of the eastern Beringian loess record can be determined using a variety of Quaternary dating methods. Tephrochronologic correlations between the loess record and the glacial history of eastern Beringia indicate the Delta Glaciation occurred during marine isotope stage 6. Several other middle and Late Quaternary glaciations across eastern Beringia can be tephrochronologically tied to the loess record| and appear to have been in phase with episodes of global cooling recorded in deep-sea records. (C) 2000 Elsevier Science Ltd. All rights reserved. 5648,2001,3,3,Control of black carbon| the most effective means of slowing global warming,Under the Kyoto Protocol of 1997| no control of black carbon (BC) was considered. Recent studies| though| have suggested that BC and non-CO2 greenhouse-gas emission controls might slow global warming. Yet| no study has compared the effects| over time| of theoretically redcing BC versus CO2 or CH4 emissions. In this study| a global model was used to compare the effects of such reductions. The model treated eight important feedbacks of aerosols to climate. Results suggest that the most efficient method of controlling global warming over the next 20-50 years| in terms of the magnitude and speed of a cooling| is control of fossilfuel BC and associated organic matter. It is further shown that late-model diesel vehicles enhance global warming more than do equivalent gasoline vehicles| yet fuel-tax and carbon-tax laws favor diesel in many countries. It is concluded that control strategies for global warming should include control of BC along with control of CO2 and other greenhouse gases.
5393,2001,3,3,Coordination and route optimization of agricultural goods transport to attenuate environmental impact,This paper reports the study made on goods flow to| from| and within the agricultural sector in Uppsala region in Sweden in 1999. Agricultural and related goods transport has increased steadily in the recent decades| and empty haulage is common (up to about 45%) in the sector. The resulting transport intensification leads to environmental degradation by contributing to air pollution| global warming| ozone depletion| resource depletion| congestion and traffic accidents. The main objective of the current work is to map out the material flow and to investigate the possibilities of coordinated transport of agricultural produce and agricultural means of production| supported by information technology. It is assumed that the information achieved through this investigation will assist to develop an effective transport-logistics system| which may enable an efficient utilization of vehicles to meet the current demand for attenuating environmental impacts. Data collection on daily goods distribution and collection including geographical location of collections/distribution points and routes was done using the global positioning system| GPS. A total of 196 routes were measured and optimization of goods distribution/collection and route was done made using the gathered data to estimate the environmental benefit. Possibilities and constraints of coordinated goods distribution and collection were analysed. Optimization of routes and distribution/collection and the computed emissions from the vehicles as a result of optimization are presented. (C) 2001 Silsoe Research Institute. 5573,2001,2,4,Coral bleaching: the winners and the losers,Sea surface temperatures were warmer throughout 1998 at Sesolto Island| Japan| than in the 10 preceding years. Temperatures peaked at 2.8 degreesC: above average| resulting in extensive coral bleaching and subsequent coral mortality. Using random quadrat surveys| we quantitatively documented the coral community structure one year before and one year after the bleaching event. The 1998 bleaching event reduced coral species richness by 61% and reduced coral cover by 85%. Colony morphology affected bleaching vulnerability and subsequent coral mortality. Finely branched corals were most susceptible| while massive and encrusting colonies survived. Most heavily impacted mere the branched Acropora and pocilloporid corals| some of which showed local extinction. we suggest two hypotheses whose synergistic effect may partially explain observed mortality patterns (i.e. preferential survival of thick-tissued species| and shape-dependent differences in colon) mass-transfer efficiency). A community-structural shift occurred on Okinawan reefs| resulting in an increase in the relative abundance of massive and encrusting coral species. 5428,2001,3,3,Cost-effective reductions of non-CO2 greenhouse gases,To date| most of the focus on greenhouse gas emission reductions has been on energy-related CO2 emissions. This is understandable since CO2 emissions currently account for about 82 percent of the total US greenhouse gas emissions weighted by 100-year global warming potentials (EPA| www.epa.gov/globalwarming/publications/emissions| 2001a).(1) However| a number of analyses suggest that the non-CO2 greenhouse gases included in the Kyoto Protocol-methane| nitrous oxide| and the high-GWP (global warming potential) gases (HFCs| PFCs| and SF6)-can make a significant contribution to cost-effective emission reductions for the US and other countries. Our current estimate for the US is a reduction in non-CO2 emissions of 105 million metric tons of carbon equivalent (MMTCE) at $50/ton carbon equivalent in 2010. This paper provides a perspective on the current and projected emissions of greenhouse gas; outlines the potential methods for achieving emissions reductions for various sources; and summarizes several recent studies on the cost of reductions for the US and other countries. Although the paper does not specifically address the potential for reductions of these gases in individual countries outside the US and the European Union| its findings are generally applicable to many countries. Published by Elsevier Science Ltd. 5568,2001,3,3,Development of environmentally-conscious steel products at the Nippon Steel Corporation,Global environmental problems| including global warming| are extremely important and urgent issues for humankind. The human society that has pursued and enjoyed only the development of global civilization now faces the challenging proposition of sustainable development. In recent years| Japan's steel industry has positioned global environmental compliance as an important objective in corporate activities and has taken Various initiatives to contribute to this sustainable development. These environmental initiatives can be considered in three main categories: (1) reduction in CO2 emissions and energy consumption; (2) promotion of recycling and zero-waste; and (3) environmental protection and environmental improvement. Based on this concept| Nippon Steel has implemented environmental measures for steel production processes and has promoted the development of various environmentally friendly products to meet the requirements of diverse consuming industries. The initiatives launched by Nippon Steel in the development of environmentally conscious steel products (eco-products) for each kind of steel market are introduced here. Representative eco-products that meet the requirements of these industries are described. The 21st Century is said to be the 'century of environment'. Steel will be continued to be utilized as an eco-material in the next century. Nippon Steel will make great contributions to global environmental protection as an 'eco-company' with 'eco-products' and 'eco-processes'. (C) 2000 Elsevier Science Ltd. AU rights reserved. 5636,2001,5,4,Did the Antarctic ice sheets expand during the early Pliocene?,Seismic data show that glacial unconformities are located within lower Pliocene strata on the Antarctic continental shelves. The glacial unconformities are significant because they provide direct evidence that the Antarctic ice sheets advanced despite the generally warmer climates and elevated sea levels that characterized most of the early Pliocene. The magnitudes of peak eustatic lowstands and O-18 enrichments indicate that the ice volume on Antarctica may have exceeded today's ice volume by approximately 18%| which suggests that the ice-sheet grounding events on the shelves probably were associated with larger than present ice volumes on two to three occasions during the early Pliocene. 3008,2001,4,4,Digital ecological model and case study on China water condition,Digital Ecological Model (DEM) is a platform developed with Java. It consists of six components: DEMGIS| DEMTSA| DEMSTA| DEMMOD| DEMVIEW| and DEMAPPLET. DEMGIS features major functions of geographic information system (GIS)| such as building digital elevation model| managing gee-referenced database| translating vector data into raster data| and generating geographic graphs with different projections. DEMTSA is used to interpolate the scattered climatic data into raster data| by means of trend surface analysis (TSA) method and interpolation method. As a plug-in for GIS| DEMSTA provides some widely used statistic methods. DEMMOD is a platform for building process-based landscape model. It provides a visual interface - Visual Programming Interface of Digital Ecological Model (DEMVPI) for ecologists to 'write' and record the models in an interpretation language - Ecological Description Language of Digital Ecological Model (DEMEDL). Ecological Model Interpreter of Digital Ecological Model (DEMEMI) is responsible for compiling the programs written in DEMEDL| running the model and displaying the results. DEMVIEW is a tool for viewing and editing some geographic graphs. DEMAPPLET can link a Java applet with gee-referenced database and display the simulation results on the Internet. All the codes of DEM were compiled into Java application programs| and some of the programs are available on the Internet as Java applets. As a case study| amended Penman's method was used to calculate the potential evapotranspiration and aridity index of China| under present situation and three prescribed climate scenarios| which include raising mean temperature by 1.5| 3.0 and 4.5 degreesC| and raising precipitation by 10%| to assess the potential impacts of global climate change on China water condition. (C) 2001 Elsevier Science B.V. All rights reserved. 5632,2001,2,4,Distribution of slushflows in northern Europe and their potential change due to global warming,The distribution of slushflows in northern Europe is described. Schematic maps of the beginning and ending periods of slushflow risk are presented. The months with maximum slushflow activity are also shown. Potential changes in the geographic and temporal distribution of slushflows due to global warming were analyzed for this region. Calculations for the year 2050 were done on the basis of climatic changes given by three global circulation models. The method of calculation was based on the general relationships between climatic parameters and the geographical and temporal distribution of slushflows. Schematic maps of potential distribution of slushflows show changes when calculated according to the most extreme of the three climatic-change scenarios. 3025,2001,4,4,Does the fresh water supply from the Amur river flowing into the sea of Okhotsk affect sea ice formation?,The impacts of ground hydrology on the high-latitude oceans| such as melting glaciers and discharge from rivers into the oceans| can affect global climate by mediating the flow of low-density| fresh water inflow that strengthens the ocean's stratification. This suppresses the thermohaline circulation| and also promotes sea-ice formation. Our time series analysis based on sea-ice and river-discharge data indicates that the effect of this fresh water on the sea-ice in the Okhotsk Sea| into which the second largest Siberian River| the Amur| discharges| is relatively unimportant. Interannual variations in the ice extent are negatively correlated with the amount of discharge. We find circumstantial evidence that the inflow of warmer river water tends to raise the sea surface temperature| and that it suppresses ice formation in the following winter. This potential explanation for the negative correlation implies that sensible heat transported by large rivers in high latitudes should be reconsidered in studying global climate change. 5607,2001,2,4,Domoic acid: a fascinating marine toxin,There are indications that toxic algal blooms are increasing because of pollution of coastal waters and worldwide shipping. This mini-review deals with the marine biotoxin domoic acid| also known as amnesic shellfish poison| and its main producing pennate diatom genus Pseudo-nitzschia (Bacillariophyceae). Besides contamination of seafood| these organisms have also been involved in human and marine wildlife mortality. The article aims to give an overview of all biological and environmental factors that should be considered when trying to evaluate a possible increase in toxic blooms of Pseudo-nitzschia spp.. Pseudo-nitzschia blooms characteristically occur in a low light regime| at a time when the temperature is falling and at a wide range of salinities. Laboratory studies have shown that the production of domoic acid| a water-soluble amino acid| is related to silicon| phosphorus| nitrogen and trace metal (mainly iron) availability. Domoic acid has no known function in defence or primary metabolism; a role in excretion of excess photosynthetic energy or as a binding ligand for trace metals is suggested. The variability in domoic acid production by different Pseudo-nitzschia spp.| or the presence of toxic and non-toxic strains of the same species| cannot be explained. The conclusion is drawn that an increase in toxic blooms of Pseudo-nitzschia spp. might be possible| especially because of the expected increase in nutrient availability from pollution and desert dust. Global warming may have an influence as well by lengthening the growth period for Pseudo-nitzschia| enlarging their global distribution and increasing the dust load through desertification. (C) 2001 Elsevier Science B.V. All rights reserved. 3021,2001,4,4,Downscaling of greenhouse gas induced climate change in two GCMs with the Rossby Centre regional climate model for northern Europe,Two 2 x 10-year climate change experiments made with the Rossby Centre regional Atmospheric climate model(RCA) are reported. These two experiments are driven by boundary data from two global climate change simulations| one made with HadCM2 and the other with ECKAM4/OPYC3| in which the global mean warming is virtually the same| 2.6 degreesC. The changes in mean temperature and precipitation show similarities (including broadly the same increase in temperature and in northern Europe a general increase in annual precipitation) as well as differences between the two RCA experiments. These changes are strongly governed by the driving GCM simulations. Even on the RCA grid box scale| the differences in change between RCA and the driving GCM are generally smaller than the differences between the two GCMs. Typically about a half of the local differences between the two RCA simulations are attributed to noise generated by internal variability| which also seems to explain a substantial part of the RCA-GCM differences particularly for precipitation change. RCA includes interactive model components for the Baltic Sea and inland lakes of northern Europe. The simulated changes in these water bodies are discussed with emphasis on the wintertime ice conditions. Comparison with an earlier RCA experiment indicates that a physically consistent treatment of these water bodies is also of importance for the simulated atmospheric climate change. 5559,2001,2,4,Drought and the consequences of El Nino in Borneo: a case study of figs,Borneo has a perhumid climate but occasional severe droughts have an important impact. Droughts may affect the composition and size structure of plant communities through differential mortality or| via their impact on the availability of plant resources| affect plant-animal interactions. From January to April 1998| northern Borneo suffered a very severe drought linked to the El Nino Southern Oscillation event of 1997-1998. In this article| the impacts of this drought on the rain forest at Lambir Hills National Park| Sarawak| are considered with special reference to a keystone plant group| the figs. Small fires entered the edge of the forest from the roadside| killing saplings| climbers| and understory trees. Community-wide mortality for adult trees was 0-7 times higher than in nondrought years| with larger trees showing a greater proportional increase. In figs| mortality was significantly higher in pioneers| but hemiepiphytes and roadside species were unaffected. Phenology was substantially affected. Leaf and flower/fruit production decreased or ceased during the drought and increased suddenly following renewed rain. Pollinators of dioecious figs became locally extinct during the drought| and other plant-animal interactions may also have been disrupted. The frequency and severity of droughts has increased substantially in the past three decades| and climate models suggest this may be the result of global warming. The impacts of the 1998 drought at Lambir Hills National Park suggest that| should this trend continue| a substantial alteration of habitats and overall loss of biodiversity can be expected in Borneo. 2977,2001,2,3,Dynamic responses of African ecosystem carbon cycling to climate change,Global climate change has been modifying ecosystem carbon cycling| which has produced feedbacks on climate by affecting the concentration of atmospheric CO2. The importance of biospheric CO2 uptake or release to climate change has generated great interest in quantifying the dynamic responses of terrestrial ecosystem carbon cycling to climate change. However| less attention has been given to Africa| although it accounts for about one-fifth of the global net primary production and is one of the regions that have the greatest climate change. Here we use a biogeochemical model to simulate the dynamic variations in the carbon fluxes and stocks of African ecosystems caused by changes in climate and atmospheric CO2 from 1901 and 1995. We estimate that climate change reduces plant production and soil carbon stocks and causes net CO2 release| but the fertilization effect of increasing atmospheric CO2 on photosynthesis reverses the reduction and leads to carbon accumulation in vegetation. Therefore| the combined effect of climate change and increasing atmospheric CO2 causes net CO2 uptake| particularly in central Africa. The mean rate of the carbon sequestration in the period 1981-1995 is calculated to be 0.34 Gt C yr(-1). Nevertheless| Africa is not necessarily a significant carbon sink| because a large part of the carbon sequestration is offset by the carbon release arising from land use changes. 5567,2001,2,4,Earlier plant flowering in spring as a response to global warming in the Washington| DC| area,Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set| the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from -3.2 to -46 days| while those for later-flowering species range from +3.1 to +10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (T-min). 5525,2001,3,3,Economic feasibility of co-producing bioethanol and glycerol from grain and cane molasses fermentations,With crude oil at $30.00 per barrel| bioethanol is a viable fuel alternative. Bioethanol is clean burning| has high octane numbers| is renewable and does not contribute to global warming. However| in the absence of tax credits| the production of bioethanol is less attractive. A determination of return-on-investment was carried out based on tests to optimise the co-production of bioethanol and a high-value product| glycerol. Using corn or mile (grain sorghum) as the raw material| the return-on-investment increases from 12.3% (bioethanol) to 19.7% (bioethanol plus glycerol). When blackstrap molasses is the raw material| the return-on-investment increases from 12.8% (bioethanol) to 22.3% (bioethanol plus glycerol). Therefore| value-added products such as glycerol are the key to making fuel ethanol plants profitable now and in the future. 3011,2001,2,4,Economic implications of potential ENSO frequency and strength shifts,Some argue that global climate change may alter the frequency and strength of extreme events. This paper examines the economic damages in the agricultural sector arising from a shift in El Nino Southern Oscillation (ENSO) event frequency and strength. The assumptions about the frequency of ENSO shift are motivated by an article by Timmermann et al. (1999). The damage estimates reported here are in the context of the global agricultural system. Annual damages in the 3 to 4 hundred million U.S. dollar range are found if only the frequency of ENSO events changes. However| annual damages rise to over $1 billion if the events also intensify in strength. Event anticipation and crop mix adaption on the part of farmers can help offset the damages but cannot fully alleviate them. 5621,2001,3,4,Effect of carvacrol and thymol on odor emissions from livestock wastes,A majority of the beef cattle and swine in the United States is produced in confined facilities. This generates significant environmental pollutants from the waste produced| including global warming gases| odor| and pathogens. The objectives of this study were to control the fermentation activity and pathogens in cattle and swine wastes with antimicrobial plant essential oils. Anaerobic one litre flasks with a working volume of 0.5 l were used to evaluate the effect of carvacrol and thymol on production of fermentation gas| short-chain volatile fatty acids| lactate| and bacterial populations. In cattle waste| 1 gl(-1) each of carvacrol and thymol completely inhibited the production of volatile fatty acids and lactate over 23 days. In swine waste| 2.5 gl(-1) carvacrol inhibited the production of all volatile fatty acids. We conclude that these essential oils are effective in controlling livestock waste odor emissions and field studies are warranted. 3009,2001,2,4,Effect of climatic gradients on the photosynthetic responses of four Phragmites australis populations,Four populations of Phragmites australis collected from geographically distinct areas in Europe were propagated in outdoor experimental plots at four sites with dissimilar climate (Denmark| The Netherlands| Spain and Czech Republic). During the second growing season the photosynthetic characteristics of Phragmites leaves were evaluated under controlled conditions for each site| each population| and their interaction| and related to tissue nutrient and pigment content. The light-saturated rate of photosynthesis (P-max)| dark respiration rate (R-d)| light compensation point (I-c)| and apparent quantum efficiency (phi (i)) were significantly affected by growth site| whereas differences between populations were less pronounced. Plants grown in the more northerly climates appeared to be more photosynthetically limited through lower P-max values and lower phi (i) levels| reflecting phenotypic acclimation to the lower summer temperatures and irradiance levels at the northern growth sites. The higher P-max levels in the southern climate were correlated with higher nutrient levels in the tissue of leaves. The study shows that the four genetically distinct populations of P. australis exhibited high phenotypic plasticity in photosynthetic response to climatic change. The degree of photosynthetic plasticity within P. australis genotypes is large| and generally larger than the genetically determined differences between European populations. The results are discussed in relation to the prospected global climate change. (C) 2001 Elsevier Science B.V. All rights reserved. 5533,2001,3,4,Effect of nitrogen plasma conditions on electrical properties of silicon oxynitrided thin films for flash memory applications,Thin silicon oxynitride films were deposited on Si(100) substrates using nitrogen plasma at various exposure times| followed by thermal oxidation in dry O-2 without the use of toxic or global warming gases. Secondary ion mass spectroscopy measurements confirmed that nitrogen is confined to the immediate vicinity of the surface. The damage induced in the thin silicon oxynitride film after exposure to nitrogen plasma for between 10 and 60 s was estimated from an analysis of capacitance-voltage and current-voltage measurements. Generation of different densities of positive oxide charge was observed. Correlation between the local bonding structures in the oxynitride films and the electrically active defective states at the oxynitride/Si interface are also discussed. It is proposed that improved electrical characteristics such as positive charge trapping| interface state density| leakage current| and stress immunity of thin silicon oxynitride films| can be obtained by using an optimal plasma exposure time of approximately 30 s. The preliminary results obtained in this study indicate that these oxynitride films can be considered as potential candidates for ultra-thin gate oxide flash memory applications. (C) 2001 Elsevier Science B.V. All rights reserved. 5471,2001,3,3,Effect of O-2(CO2)/C4F8O gas combinations on global warming gas emission in silicon nitride PECVD plasma cleaning,In this study| O-2/C4F8O and CO2/C4F8O have been used as the chemicals for plasma-enhanced chemical vapor deposition (PECVD) chamber-cleaning of silicon nitride| and the effects of gas mixture and operational pressure on the silicon-nitride cleaning rate and emission properties| such as emission species| destruction and removal efficiencies (DREs)| and million metric tons of carbon equivalent (MMTCE)| have been investigated. O-2/C4F8O generally showed a higher silicon-nitride cleaning rate compared to CO2/C4F8O| possibly due to the removal of fluorine by carbon in CO2. The highest silicon-nitride cleaning rate obtained with O-2/C4F8O was approximately 600 nm/min for 80% O-2/20% C4F8O at 66.7 Pa (500 mtorr)| 40 sccm| 150 W of 13.56-MHz RF power| and without substrate heating. Emission species| such as CF4| COF2 and CO2| were observed through the exhaust line during silicon nitride cleaning| in addition to the undestructed remaining feed gases. The quantities of these emission species were higher than that of C4F8O fed through the cleaning chamber. With 80% O-2/20% C4F8O| the highest DREs and the lowest MMTCE obtained were 92% and 3 X 10(-10) respectively. In the case of CO2/C4F8O| silicon nitride cleaning rates were lower| the DRE was lower and MMTCEs were higher than those of O-2/C4F8O. (C) 2001 Elsevier Science B.V. All rights reserved. 2996,2001,2,4,Effect of the 1997-1998 ENSO-related drought on hydrology and salinity in a Micronesian wetland complex,The potential effects of global climate change on coastal ecosystems have attracted considerable attention| but the impacts of shorter-term climate perturbations such as ENSO (El Nino-Southern Oscillation) are lesser known. In this study| we determined the effects of the 1997-1998 ENSO-related drought on the hydrology and salinity of a Micronesian mangrove ecosystem and an adjacent freshwater swamp. A network of 9 piezometer clusters installed at the study site served as sampling points for continuous and manual measurements of salinity and water level. During the drought period from January through April 1998| mean water table levels in the mangroves and freshwater swamp were approximately 12 and 54 cm lower| respectively| than during May through December when precipitation returned to near normal levels. At the peak of the drought (February 1998)| the most dramatic result was a reversal in groundwater flow that sent groundwater from the mangroves upstream toward the freshwater swamp. Flow nets constructed for this period and immediately after illustrate the strong hydrological linkage between the two systems. This linkage was also illustrated by measurements of groundwater salinity in the piezometer network. Ninety-six percent of the salinity measurements taken in the mangroves during the study were at least 10 parts per thousand less than the salinity of sea water| indicating that the mangroves were consistently receiving freshwater flows. An analysis of variance of groundwater salinity measurements during and after the drought showed that salinity levels in the 0.5 and 1.0 m depth piezometers were greater during than after the drought. In a comparison of salinity values in 0.5-m wells during low tide| mean salinity was approximately twice as high during the drought than after (14.7 parts per thousand versus 6.2 parts per thousand| respectively). This study demonstrates that short-term climate perturbations such as ENSO can disrupt important coastal processes. Over repeated drought cycles| such perturbations have the potential to affect the structure and function of mangrove forests and upstream ecosystems. 2988,2001,2,4,Effects of climatic change on a water dependent regional economy: A study of the Texas Edwards Aquifer,Global climate change portends shifts in water demand and availability which may damage or cause intersectoral water reallocation in water short regions. This study investigates effects of climatic change on regional water demand and supply as well as the economy in the San Antonio Texas Edwards Aquifer region. This is done using a regional model which portrays both hydrological and economic activities. The overall results indicate that changes in climatic conditions reduce water resource availability and increase water demand. Specifically| a regional welfare loss of $2.2-$6.8 million per year may occur as a result of climatic change. Additionally| if springflows are to be maintained at the currently desired level to protect endangered species| pumping must be reduced by 9-20% at an additional cost of $0.5 to $2 million per year. 5413,2001,2,3,Effects of glacial meltwater in the GISS coupled atmosphere ocean model - 1. North Atlantic Deep Water response,Varying magnitudes of freshwater input through the St. Lawrence are added to different versions of the GISS coupled atmosphere-ocean model. The results show a generally linear response in percentage North Atlantic Deep Water (NADW) reduction to the volume of water added without any obvious threshold effects. When the estimated best guess freshwater input for the Allerod-Younger Dryas interval is added| only small reductions in NADW production occur in less than a century| with complete cessation requiring more than 300 years. If the ocean circulation was weaker in the Allerod preceding the Younger Dryas| somewhat larger percentage reductions occur| and it would take 150-200 years for a complete shutdown. The freshening is aided by a positive feedback associated with the reduction in evaporation relative to precipitation in the North Atlantic| amounting to some 20-30% of the added freshwater runoff. When the freshwater input is stopped after complete NADW shutdown| NADW production does not resume. With complete NADW cessation| cooling eventually occurs throughout the Northern Hemisphere| including regions where it is not thought to have arisen during the Younger Dryas| and the globe cools by 1 degreesC due primarily to the sea ice albedo feedback; while in many regions the observed cooling is reproduced| the cooling in Greenland is much less than is estimated. With only 50% NADW cessation| cooling is primarily around the North Atlantic| No rapid warming is seen in response to freshwater cessation. The sensitivity displayed here for NADW reduction due to freshwater input from the St. Lawrence is roughly similar to that associated with increased precipitation accompanying global warming in the next century| so a similar sensitivity may arise with Younger Dryas freshwater inputs from other suspected locations (Greenland| Europe). 3018,2001,2,4,Effects of global climate change on coastal salt marshes,A methodology combining ecological modelling with geographical information analysis and remote sensing was employed to determine the effects of sea-level rise in estuarine salt marshes| using the Tagus estuary (Portugal) as a case study. The development of salt marsh vegetation was simulated separately for C3 and C4 plants| using a combined biogeochemical and demographic model. This simulation| which provided small-scale (m(2)) results of annual above-ground primary production| was upscaled to the whole salt marsh area| using bathymetry data| remote sensing and Geographic information System (GIS) for assessing vegetation cover and determining areal distribution of C3 and C4 vegetation. Based on IPCC data| several sea-level rise scenarios were considered| and the coupled ecological model-GIS were applied to these in order to determine changes in global salt marsh productivity. The results indicate that the salt marshes of the mesotidal estuaries such as the Tagus are susceptible to sea-level rise only in a worst case scenario| which is more likely to occur if the terms set out by the Kyoto protocol are not met by several industrialised nations. The low vulnerability of salt marshes supports the suggestion that areas with high tidal ranges are less vulnerable to sea level change| due to greater sediment transport and accretion. Nevertheless| the precautionary principle should always be applied by coastal planners| due to the great uncertainty surrounding forecasts of sea-level rise. (C) 2001 Elsevier Science B.V. All rights reserved. 2965,2001,2,4,Effects of global climate change on geographic distributions of Mexican Cracidae,Although climate change and its implications are a frequent subject of detailed study| the effects of these changes on species' geographic distributions remain little explored. We present a first cross-species analysis of the effects of global climate change on the distributions of one bird family| the Cracidae| in Mexico| based on projecting models of ecological niches from present conditions to modeled future conditions taken from general circulation models of climate change. Based on two different scenarios of climate change and on three assumptions regarding species' dispersal abilities| effects on species' distributions range from drastic reduction to modest increases. These results illustrate the complex nature of species' geographic responses to environmental change| and emphasize the need for detailed analysis of individual species' ecological requirements. (C) 2001 Elsevier Science B.V. All rights reserved. 5587,2001,2,4,Effects of simulated climate change on the hydrology of major river basins,Changes in the climatology of precipitation| evapotranspiration| and soil moisture lead also to changes in runoff and streamflow. The potential effects of global warming on the hydrology of 23 major rivers are investigated. The runoff simulated by the Canadian Cetre for Climate Modeling and Analysis (CCCma) coupled climate model for the current climate is routed through the river system to the river mouth and compared with results for the warmer climate simulated to occur towards the end of the century. Changes in mean discharge| in the amplitude and phase of the annual streamflow cycle| in the annual maximum discharge (the flood) and its standard deviation| and in flow duration curves are all examined. Changes in flood magnitudes for different return periods are estimated using extreme value analysis. In the warmer climate| there is a general decrease in runoff and 15 out of the 23 rivers considered experience a reduction in annual mean discharge (with a median reduction of 32%). The changes in runoff are not uniform and discharge increases for 8 rivers (with a median increase of 13%). Middle- and high- latitude rivers typically show marked changes in the amplitude and phase of their annual cycle associated with a decrease in snowfall and an earlier spring melt in the warmer climate. Low-latitude rivers exhibit changes in mean discharge but modest changes in their annual cycle. The analysis of annual flood magnitudes show that 17 out of 23 rivers experience a reduction in mean annual flood (a median reduction of 20%). Changes in now duration curves are used to characterize the different kinds of behavior exhibited by different groups of rivers. Differences in the regional distribution of simulated precipitation and runoff for the control simulation currently limit the application of the approach. The inferred hydrological changes are| nevertheless| plausible and consistent responses to simulated changes in precipitation and evapotranspiration and indicate the kinds of hydrological changes that could occur in a warmer climate. 5401,2001,4,3,Effects of stabilizing atmospheric CO(2) on global climate in the next two centuries,Previous coupled ocean-atmosphere model simulations showed that the reduction in global warming is only moderate by year 2100 under CO(2) stabilization (STA) scenarios compared with that under business-as-usual (BAU) scenarios. To further illustrate the long-term effect of stabilizing CO(2) on global climate| we integrated a coupled ocean-atmosphere model from 1870 to 2200 forced by historical and projected CO(2)| SO(2) and other greenhouse gases under newly updated BAU and STA scenarios. Our results show that the reduction in global warming resulting from CO(2) stabilization could be large (similar to1.5 degreesC globally| and up to 12 degreesC in DJF at northern high-latitudes) by the later part of the 22(nd) century. Stabilizing the CO(2) level also results in reduced changes in precipitation| soil moisture and diurnal temperature range. BAU and STA patterns of change are similar for all variables examined. 5450,2001,2,4,Emerging paradigms for water management in the 21st century - Lecture Enzo Levi 2000,The objective of this paper is to show that water resources management is going through a deep crisis that will be overcome only if a substantial change towards new mental models| new paradigms of water management is produced. An overview of the present water problems in Mexico and worldwide is presented| including global uses| consumption practices and trends. The discussion includes the foreseeable effects on water resources of the global warming as well as some of the ruling principles that| according to the author's point of view| will constitute the base of new thinking models in water management: a global approach to water management| world vision of water and its five ruling conditions| systemic thinking and integrated management. An application of the systemic archetypes to the overexploitation of aquifers is also presented. 5472,2001,3,4,Emissions of ammonia| nitrous oxide and methane from different types of dairy manure during storage as affected by dietary protein content,In a storage experiment with dairy cow manure| the effects of dietary protein content and manure type on ammonia| nitrous oxide and methane volatilization as well as overall nitrogen (N) loss from manure were investigated. Early-lactating cows received rations with 175| 150 and 125 g crude protein/kg dry matter. Each ration was tested in four manure storage systems reflecting typical farm conditions. These either contained total excreta with high amounts of straw (deep litter manure) or no straw (slurry) or| proportionately| 0.9 of urine and 0.1 of faeces (urine-rich slurry) complemented by the residuals with a low amount of straw (farmyard manure). Manure samples were stored for 7 weeks under controlled conditions and trace gas emission was repeatedly measured. Reduction of N intake decreased daily N excretion and urine N proportion and| on average| led to 0.7-fold lower storage ammonia emission rates on average. Total storage N loss was simultaneously reduced with the extent depending on urine N proportion of the respective manures. A lower dietary protein content furthermore reduced nitrous oxide emission rates in most manure types but increased methane emission from urine-rich slurry; however| global warming potential (based on trace gas output) of all manures was similar with low and high dietary protein content. In deep litter manure| characterized by the highest C: N ratio| emission rates of total N| ammonia and methane were lowest| whereas nitrous oxide values were intermediate. Substantial emission of nitrous oxide occurred with farmyard manure which also had the highest methane values and| consequently| by far the highest global warming potential. C: N ratio of manure was shown to be suitable to predict total N loss from manure during storage in all manure types whereas urine N proportion and manure pH were only of use with liquid manures. 5431,2001,3,3,Emissions of greenhouse gases and other airborne pollutants from charcoal making in Kenya and Brazil,Airborne emissions from charcoal-making kilns commonly used in Kenya and Brazil were measured during typical operating conditions. Emission factors were determined for carbon dioxide (COD| methane (CH4)| nitrous oxide (N2O)| carbon monoxide (CO)| total nonmethane hydrocarbons| nitrogen oxides (NO|) and total suspended particulates (TSP) along with charcoal production efficiency and charcoal and fuelwood carbon and energy contents. The conversion of wood carbon to charcoal carbon ranged from 37 to 69%| depending on kiln type. Emission factors| expressed as grams of pollutant per kilogram of charcoal produced| for the eight kilns ranged from 543 to 3027 for CO2| 32-62 for CH4| 143-373 for CO| 24-124 for total nonmethane organic compounds| 0.011-0.30 for N2O| 0.0054-0.13 for NOx| and 13-41 for TSP. On average| fuelwood carbon was approximately diverted as follows: 51 % to charcoal| 27% to CO2| and 13% to products of incomplete combustion (PIC). Due to the higher global warming potentials (GWPs) of PIC relative to CO2 on a carbon atom basis| such kilns can produce rather large net greenhouse gas emissions| even when the wood is harvested renewably. Based on published GWPs for CO2| CH4| and N2O only| we estimate that 0.77-1.63 kg C-CO2 (carbon as carbon dioxide equivalents) is emitted per kilogram of charcoal produced. We estimate that the total primary global warming commitment (GWC) of Kenyan and Brazilian charcoal-making kiln emissions is about 2.7 and 7.5 million tons (Mt) C-CO2| respectively. For comparison| the primary GWC from fossil fuel use in the United States is almost 1700 Mt C-CO2. 5408,2001,4,3,Emissions of greenhouse gases from the tropical hydroelectric reservoir of Petit Saut (French Guiana) compared with emissions from thermal alternatives,Greenhouse gas (GHG) emissions of CH4 and CO2| resulting from decomposition of flooded organic matter from the hydroelectric reservoir of Petit Saut in the tropical rain forest of French Guiana have been monitored since reservoir impoundment in January 1994. This data set along with complementary data taken from older reservoirs in forested regions of the southern Ivory Coast provides an estimate of long-term GHG emission trends from a tropical reservoir. The trends are used to calculate the contribution of this reservoir to global warming on a 100 year timescale| assumed to be consistent with the life cycle of the reservoir. Calculations are based on the concept of global warming potential (GWP). Natural emission of greenhouse gases (CH4 and N2O) from soils of the reservoir before impoundment is estimated through field measurements and literature data. Then net GHG emissions from the reservoir on a 100 hundred year timescale (30 million tons of equivalent CO2| with an uncertainty range of 7-54 Mt CO2eq) are compared with predicted emissions from thermal power plants of equivalent power (115 MW). The final comparison takes into account the actual energy production of the dam power station at only 50% of the installed capacity. Emission from this reservoir| whose power density is low (0.315 MW km(-2) flooded)| would be similar to emissions from a gas power plant (33 Mt CO2eq) producing the same energy amount and less than emissions from other thermal alternatives| among which the most polluting are coal plants. Such a result| however| strongly depends on the choice of the integration time. 5437,2001,3,4,Energy accounting and well-being - examining UK organic and conventional farming systems through a human energy perspective,This paper quantifies and compares the energy efficiencies of conventional and organic farming systems in the UK from a human energy perspective. To date| studies comparing these two systems have neglected rudimentary questions regarding the effort and energy expenditure of farmers| instead devoting attention to consumer health and selected environmental issues such as global warming and recent energy crises. The need to focus on the human energy problem is seen as fundamental in this paper as it concerns not just the balance of calorific expenditure and consumption but also the possible negative health affects associated with high levels of energy and effort expenditure. Assessment of human energy expenditures and effort| and their health effects is relatively under-developed; consequently this paper uses a pilot study to explore methodology on which future study and theory could be based. The method developed draws on three plausible models for assessing human energy and effort expenditure: the nutritional| physiological and ergonomic. The case study builds annual and daily profiles of energy and effort expenditure of two farmers using annual tabour profiles and task specific energy expenditure and intensity derived from physical measurements. Although the scope of the experiment is limited| making inferences about each system is difficult| the results reveal clear differences in the annual energy and effort expenditures of the two farmers. Over a typical year the organic farmer experiences far more physical stress. Despite being more efficient in terms of overall energy| the organic farm is less efficient in terms of human energy| and the net energetic returns combined with effort intensity bring into question the health implications of organic livelihoods both in the short and long term. (C) 2001 Elsevier Science Ltd. All rights reserved. 5613,2001,4,4,Energy and water balance studies of a snow cover during snowmelt period at a high arctic site,The predicted global warming is supposed to have an enhanced effect on the arctic regions. How this will influence the water| carbon dioxide and methane balances in the European arctic tundra is the objective of the EU-funded project "Understanding Land Surface Physical Processes in the Arctic" (LAPP)| to which where SINTEF is one of several contributors. The snow cover is one of the limiting factors for these exchange processes and knowledge of how it behaves and will behave under a different climate is important. Data collected for water and energy balance studies in an area close to Ny-Angstrom lesund at 79 degreesN at Svalbard are the basis of this study. Measurements during the ablation periods since 1992 show an average air temperature for the periods of 2.1 degreesC| an average incoming shorwave radiation of 230 W/m(2) and an average measured runoff intensity of 14 mm/day with a maximum of 68 mm/ day. Three models of different complexity are tested in order to simulate the water and energy balance of a snow cover on the arctic tundra. The three models are: a complex numerical model (CROCUS)| a simple energy balance model and a temperature index model. The simulations were carried out for the melt periods in 1992 and 1996 as these two periods represent very different meteorological conditions. The results of these simulations exposed weaknesses in all the models. The energy balance model lacks calculation of cold content in the snowpack. This influences both the outgoing longwave radiation and the timing of the melt. Due to the effect of compensating errors in the simulations| CROCUS performed better than the simple energy balance model but also this model has problems with the simulation of outgoing longwave radiation. The temperature index model does not perform well for snowmelt studies in regions were radiation is the main driving energy source for the melt. 5463,2001,3,4,Energy for the new millennium,The evolution of thinking about energy is discussed. When the authors began collaborating 20 years ago| energy was typically considered from a growth-oriented| supply-side perspective| with a focus on consumption trends and how to expand supplies to meet rising demand. They were deeply troubled by the environmental| security and equity implications of that approach. For instance| about two billion people lack access to affordable modern energy seriously limiting their opportunities for a better life. And energy is a significant contributor to environmental problems| including indoor air pollution| urban air pollution| acidification| and global warming. The authors saw the need to evolve a different perspective in which energy is provided in ways that help solve such serious problems. They argued that energy must become an instrument for advancing sustainable development-economically viable| need-oriented| self-reliant and environmentally sound development-and that the focus should be on the end uses of energy and the services that energy provides. Energy technological options that can help meet sustainable development goals are discussed. The necessity of developing and employing innovative technological solutions is stressed. The possibilities of technological leapfrogging that could enable developing countries to avoid repeating the mistakes of the industrialized countries is illustrated with a discussion of ethanol in Brazil. The role foreign direct investment might play in bringing advanced technologies to developing countries is highlighted. Near-and long-term strategies for rural energy are discussed. Finally| policy issues are considered for evolving the energy system so that it will be consistent with and supportive of sustainable development. 5416,2001,4,3,Ensemble simulation of twenty-first century climate changes: Business-as-usual versus CO2 stabilization,Natural variability of the climate system imposes a large uncertainty on future climate change signals simulated by a single integration of any coupled ocean-atmosphere model. This is especially true for regional precipitation changes. Here| these uncertainties are reduced by using results from two ensembles of five integrations of a coupled ocean-atmosphere model forced by projected future greenhouse gas and sulfate aerosol changes. Under a business-as-usual scenario| the simulations show a global warming of similar to1.9 degreesC over the. twenty-first century (continuing the trend observed since the late 1970s)| accompanied by a similar to3% increase in global precipitation. Stabilizing the CO2 level at 550 ppm reduces the warming only moderately (by similar to0.4 degreesC in 2100). The patterns of seasonal-mean temperature and precipitation change in the two cases are highly correlated (r approximate to 0.99 for temperature and r approximate to 0.93 for precipitation). Over the midlatitude North Atlantic Ocean| the model produces a moderate surface cooling (1 degrees -2 degreesC| mostly in winter) over the twenty-first century. This cooling is accompanied by changes in atmospheric lapse rates over the region (i.e.| larger warming in the free troposphere than at the surface)| which stabilizes the surface ocean. The resultant reduction in local oceanic convection contributes to a 20% slowdown in the thermohaline circulation. 5538,2001,2,3,ENSO-Monsoon relationships in a greenhouse warming scenario,Recent studies based on observed climatic data indicate: weakening of the relationship between EI Nino-Southern Oscillation (ENSO) and Indian summer monsoon rainfall| possibly due to global warming. Transient climate change simulations of a coupled ocean-atmosphere GCM (ECHAM4/OPYC3) project a change towards enhanced ENSO activities in the tropical Pacific| as well as increase in mean monsoon rainfall and variability over India. However| the interannual correlations between the mio are strong throughout the 240 year simulation. Analysis of monsoon viz-a-viz ENSO in the model simulations suggest a diminished impact of warm ENSO (El Nino) events on monsoon| while the impact of cold ENSO (La Nina) events remains unchanged in the scenario. Anomalous warming over the Eurasian landmass as well as enhanced moisture conditions over the Indian monsoon region in the global warming scenario have possibly contributed to the weakening of the impact of warm ENSO) events on monsoon. 5622,2001,3,3,Environmental accounting - a decision support tool in WWTP operation and management,The various emissions to water| air and soil from the municipal wastewater treatment plant of Avedore Wastewater Service Company are accounted for and quantified in terms of the environmental impacts to which they contribute: global warming| acidification| eutrophication| space demand for controlled deposition of residues| as well as persistent toxicity| human toxicity and eco-toxicity. The impacts are expressed on the same scale| namely as fraction of the total per capita loads in a national scenario 1990| also called the person equivalent or PE1990. This provides a compact and informative overview of the environmental impacts and allows for a holistic prioritisation in the operation and management of the plant. The accounting shows that the resulting emissions per person in the catchment area of the plant correspond to 0.5-5.0% of the average Danish PE1990 for the impacts in question. 5542,2001,3,3,Environmental aspects of electricity generation from a nanocrystalline dye sensitized solar cell system,A Life Cycle Assessment| LCA| of a nanocrystalline dye sensitized solar cell (ncDSC) system has been performed| according to the ISO14040 standard. In brief| LCA is a tool to analyse the total environmental impact of a product or system from cradle to grave. Six different weighing methods were used to rank and select the significant environmental aspects to study further. The most significant environmental aspects according to the weighing methods are emission of sulphur dioxide and carbon dioxide. Carbon dioxide emission was selected as the environmental indicator depending on the growing attention on the global warming effect. In an environmental comparison of electricity generation from a ncDSC system and a natural gas/combined cycle power plant| the gas power plant would result in 450 g CO2/kWh and the ncDSC system in between 19-47 g CO2/kWh. The latter can be compared with 42 g CO2/kWh| according to van Brummelen et al. "Life Cycle Assessment of Roof Integrated Solar Cell Systems| (Report: Department of Science| Technology and Society| Utrecht University| The Netherlands| 1994)" for another thin film solar eel system made of amorphous silicon. The most significant activity/component contributing to environmental impact over the Life cycle of the ncDSC system is the process energy for producing the solar cell module. Secondly comes the components; glass substrate| frame and junction box. The main improvement from an environmental point of view of the current technology would be an increase in the conversion efficiency from solar radiation to electricity generation and still use low energy demanding production technologies. Also the amount of material in the solar cell system should be minimised and designed to maximise recycling. (C) 2000 Elsevier Science Ltd. All rights reserved. 5585,2001,3,3,Environmental challenges of animal agriculture and the role and task of animal nutrition in environmental protection - Review,Animals are one of the important memberships of the food chain. The low-efficiency rule of nutrient transfer from one member to the next in the food chain determines the low efficiency of animal agriculture for human food. On the average| about 20% feed proteins and 15% feed energy can be converted into edible nutrients for humans. The rest proportion of feed nutrients is exposed to the environment. Environmental pollution| therefore| is inevitable as animal agriculture grows intensively and extensively. The over-loading of the environment by nutrients such as nitrogen| phosphorus from animal manure results in soil and water spoilage. The emission of gases like CH2| CO2| SO2| NO| NO2 by animals are one of the contributors for the acidification of the environment and global warming. The inefficient utilization of natural resources and the probable unsafety of animal products to human health are also a critical environmental issue. Improving the conversion efficiency of nutrients in the food chain is the fundamental strategy for solving environmental issues. Specifically in animal agriculture| the strategy includes the improvements of animal genotypes| nutritional and feeding management| animal health| housing systems and waste disposal programs. Animal nutrition science plays a unique and irreplaceable role in the control of nutrient input and output in either products or wastes. Several nutritional methods are proved to be effective in alleviating environmental pollution| A lot of nutritional issues| however| remain to be further researched for the science of animal nutrition to be a strong helper far sustainability of animal agriculture. 5553,2001,5,4,Environmental change and rates of evolution: the phylogeographic pattern within the hartebeest complex as related to climatic variation,Global climate fluctuated considerably throughout the Pliocene-Pleistocene period| influencing the evolutionary history of a wide array of species. Using the phylogeographic patterns within the hartebeest (Alcelaphus buselaphus (Pallas| 1766)) complex| we evaluated the evolutionary consequences of such environmental change for a typical large mammal ranging on the African savannah. Our results| as generated from two mitochondrial DNA markers (the D-loop and cytochrome b)| suggest an origin of the hartebeest in eastern Africa from where the species has colonized other parts of the continent. Phylogenetic analyses revealed an early diversification into southern and northern hartebeest lineages| an event that may be related to the formation of the Rift Valley lakes. The northern lineage has further diverged into eastern and western lineages| most probably as a result of the expanding central African rainforest belt and subsequent contraction of savannah habitats during a period of global warming. The diversification events appear to have coincided with major climatic changes and are highly correlated in time. These observations strongly suggest that large-scale climatic fluctuations have been a major determinant for the species' evolutionary history and that hartebeest evolution has mainly taken place in isolated yet environmentally favourable refugia during periods of global warming. Indications of sudden population expansion for two putative ancestral hartebeest populations provide further support for a refugia-based explanation of the diversification events. Reciprocal monophyly between southern and northern lineages may suggest that reproductive barriers exist and that the hartebeest complex comprises two different species. 5532,2001,3,4,Environmentally friendly wafer production: NF3 remote microwave plasma for chamber cleaning,For NF3 remote microwave plasma chamber cleaning| compared with CF4 cleaning processes| a reduction of emission of gases relevant to global warming is observed. At the same time a reduction of operating costs for the abatement is possible. The presented data show a very high destruction and removal efficiency for NF3 and its major decomposition product F-2 in an ESCAPE abatement system. (C) 2001 Published by Elsevier Science B.V. 5510,2001,3,3,Equations of state for fluorinated ether refrigerants| pentafluoroethyl methyl ether and heptafluoropropyl methyl ether,Thermodynamic properties of two fluorinated ethers| that meet the criteria of the potential new-generation refrigerants with considerably low global warming potential (GWP) and the zero ozone depletion potential (ODP)| are studied in the present paper. The recommended candidates are pentafluoroethyl methyl ether| CF3CF2OCH3 (245cbE beta gamma)| and heptafluoropropyl methyl ether| CF3CF2CF2OCH3 (347sE gamma delta)| proposed as alternative refrigerants to replace 1|2-dichloro-1|1|2|2-tetrafluoroethane| CClF2CClF2 (R-114) and trichlorofluoromethane| CCl3F (R-11)| respectively. The present paper summarizes the current thermodynamic property studies of the above fluorinated ethers| and their thermodynamic property modeling will be presented. The formulations are developed exclusively on the basis of the PVT property data| both in the single phase and at the saturation states. Using estimated ideal gas heat capacity data| derived properties including heat capacities and speeds of sound are calculated in a wide range of temperature and pressure| and their behaviors show the typical and physically sound characteristics of pure fluid. (C) 2001 Elsevier Science B.V. All rights reserved. 5518,2001,3,4,Estimating CO2 abatement and sequestration potentials for Chile,The need for the Chilean government to adopt a position vis-a-vis negotiations at the Conference of the Parties to the United Nations Framework Convention on Climate Change prompts a preliminary analysis in this paper of the results of reductions of greenhouse gases (GHG) and their costs For Chile. Basically| two sectors offer possibilities to contribute to the control of CO2 emissions. In the energy sector| CO2 emissions can be abated by either adopting more efficient technologies or switching fuels. In the non-energy sector| CO2 emissions can be sequestered from the atmosphere by afforestation| reforestation and forest management. This work represent the first effort in Chile to estimate the costs of CO2 abatement and sequestration for Chile using a bottom-up approach for the year 2010| which in a global warming context is a short/medium term scenario. In the energy sector| the end and intermediate uses of energy are considered for the transportation| manufacturing and electricity sectors. In the non-energy sector| sequestration costs incurred in forestation on marginal land available in each administrative region of Chile are estimated. Our preliminary results indicate that Chile has a large potential to become a net remover of GHG emissions| with a 176% of CO2 equivalent reduction attainable by 2010 under the upper-bound scenario. A 7% CO2 abatement can be achieved at apparently no cost to society with increased efficiency in the use of energy| and a 114% abatement can be achieved at moderate costs| i.e.| less than 11 US$/ton CO2 eq. The major reduction is obtainable through CO2 sequestration by forests. (C) 2001 Published by Elsevier Science Ltd. 3024,2001,2,3,Estimating the thickness of the free gas zone beneath Hydrate Ridge| Oregon continental margin| from seismic velocities and attenuation,Recent Ocean Drilling Program (ODP) results in the Oregon accretionary prism and on the Blake Ridge indicate that the zone containing free gas beneath the hydrate-bearing near-surface sediments is considerably thicker than previously thought. In this paper| we present results from travel time inversion of refracted seismic waves that show very low (<1.85 km/s) velocities extending for 500-600 m beneath the base of the gas hydrate stability zone in Hydrate Ridge on the Oregon continental margin near ODP site 892. The low-velocity near-surface layer extends across Hydrate Ridge and beneath the adjacent continental slope to the east. Because Pliocene sediments are exposed at the crest of Hydrate Ridge in an erosional setting| we suggest that these low velocities indicate the extent of a zone of dispersed free gas rather than recent sedimentation. Strong frequency-dependent attenuation of amplitudes is observed for P waves crossing this zone. Amplitude spectra| referenced to spectra for similar accretionary complex paths that do not cross the interpreted gassy layer| indicate a very low P wave quality factor (Q(P)) within this zone| with Q(P)Although the idea of injecting gases to improve oil recovery has been known for over three-quarters of the past century| it appears to be taking on a new meaning as we step into the new millennium. The oil price scenario remains consistently loyal to its roller-coaster past; the long awaited jump in the natural gas price has become a reality; the oil industry has made new strides in horizontal drilling with significant cost reductions; and the world's attention is focused on the industrialized nations to lead the way to control global warming by reducing greenhouse gas emissions. These evolving global issues combined with the ever-declining reserves of conventional crude oils appear to bring a new optimism to enhanced oil recovery (EOR) by gas injection. Added to this optimism are the well-accepted facts that waterflood recovery from conventional oil reservoirs rarely exceed 40% of the original oil in place (OOIP); that most waterfloods are maturing or close to their economic limits; and that chemically enhanced waterfloods appear to have become practically extinct in spite of their conceptual soundness. Therefore| gas-based EOR processes using horizontal wells appear to be the solitary hope for continual:profitable production from the large remaining reserves of conventional oil in Canada| the United States and the rest of the world. In what follows| we will briefly discuss-but not review the conceptual basis for gas injection EOR processes and what| we| have conveniently overlooked in it| the historical developments| process design considerations| problem ar eas| and the future direction and potential of this time-tested technology.
5390,2001,2,4,Genetic shift in photoperiodic response correlated with global warming,To date| all altered patterns of seasonal interactions observed in insects| birds| amphibians| and plants associated with global warming during the latter half of the 20th century are explicable as variable expressions of plastic phenotypes. Over the last 30 years| the genetically controlled photoperiodic response of the pitcher-plant mosquito| Wyeomyia smithii| has shifted toward shorter| more southern daylengths as growing seasons have become longer. This shift is detectable over a time interval as short as 5 years. Faster evolutionary response has occurred in northern populations where selection is stronger and genetic variation is greater than in southern populations. W. smithii represents an example of actual genetic differentiation of a seasonality trait that is consistent with an adaptive evolutionary response to recent global warming. 5557,2001,2,4,Geographic variation in growth responses in Phragmites australis,Phragmites australis is a cosmopolitan wetlands species occurring in a wide range of climatic habitats| It can be assumed that adaptations to climate have evolved to enable the synchronization of growth with the seasonality of the environment. To study these adaptations| European P. australis was collected in different geographic regions| and grown in common environments situated in the Czech Republic| Denmark and The Netherlands. Phragmites australis originating from higher latitudes showed higher relative length growth rates (RLGR)| and flowered earlier in time than that from lower latitudes. Plants from Spain even continued growth until the first autumn frosts. When grown in the different common environments| population differences were found in RLGR| but no general trend was apparent. On average| shoots started to grow 2 weeks earlier in The Netherlands than in Denmark and 6 weeks earlier than in the Czech Republic. These differences could be largely related to lower spring temperatures in the latter two countries. When shoot-growth was plotted against the temperature sum| no differences in RLGR between Denmark and The Netherlands were apparent| whereas shoot-growth was slower in the Czech Republic. Results from a greenhouse experiment showed that seedlings from southern populations formed taller but fewer shoots and thicker but shorter rhizomes than those from northern populations| irrespective of total dry weight. They also allocated more dry matter to stems at the expense of leaves| whereas no differences in allocation to below-ground plant parts were found. It was concluded that populations of P. australis showed clinal variation in (i) the length of the growing season| (ii) time of flowering| and (iii) morphology and biomass allocation. These results are discussed with respect to the possible effects of global warming on population functioning. (C) 2001 Elsevier Science B.V. All rights reserved. 5423,2001,5,4,Geology and geomorphology of the European Alps and the Southern Alps of New Zealand - A comparison,The European Alps (Alps) and Southern Alps of New Zealand (Southern Alps) are both high mountain ranges formed by the collision of tectonic plates. The Alps resulted from collision of the African and European Plates| which produced complex lithological and structural patterns associated with the development of a series of overthrusted nappes. In contrast| the plate margin deformation that created the Southern Alps produced a relatively simple structural and lithological pattern dominated by a single right lateral oblique slip fault zone known as the Alpine Fault. Strong contrasts are also apparent in the contemporary rates of landscape development. The Alps currently experience modest rates of uplift and denudation because deformation along the plate boundary has slowed. High rates of compressional strain along the Alpine Fault in New Zealand result in very high rates of uplift. These processes and the position of the mountain range across the prevailing atmospheric westerly circulation system result in exceptionally high rates of denudation. Although there are strong contrasts in the lithology and structure of the Alps and Southern Alps| both experienced the growth and decay of expanded valley and piedmont glaciers during the Quaternary. The impact of multiple Quaternary ice advances has left a strong imprint on the landscapes. Both mountain ranges have particularly well-developed| over-deepened troughs and widespread glacial sediments and landforms| which heavily influence modern geomorphic processes and land use. Today numerous glaciers in both regions show strong reactions to global warming since the end of the Little Ice Age. 5385,2001,2,4,Geostatistical regional trend detection in river flow data,Many studies have identified global warming and climate change as some of the biggest challenges facing Canada. In this paper| the regional temporal trend in river flows is investigated using a space-time model. Though the primary focus is the time component| the spatial relationship among monitoring stations in a region is used to develop a space-time model that is composed of a random time trend as a function of space| and a random error term as a function of both time and space. The estimate of regional time trend is a linear combination of the differenced observations that minimizes the variance of estimated errors. Data from 248 river stations in the Reference Hydrometric Basin Network (RHBN) established by Environment Canada is analysed. These hydrological monitoring stations are grouped into ten non-overlapping homogeneous regions covering all of Canada. An estimate of trend| along with its variance| is calculated for each region. Some significant trends are found for the annual mean| maximum and minimum flows| as well as for the mean monthly flows for July and December| and are consistent with those detected in other Canadian studies. Copyright (C) 2001 John Wiley Sons| Ltd. 2978,2001,2,4,Getting warmer: Effect of global climate change on distribution of rodents in Texas,Historically| distributions of plants and animals have shifted with changes in regional and global temperatures. Current predictions from general circulation models show changes in level and variation in temperature and rainfall over the next several decades. The magnitude and direction of such changes vary regionally. Studies are beginning to show that these changes will impact distribution of species of plants and animals.| and| concomitantly| species composition of plant and animal communities. We used geographic information systems| vegetation models. and general circulation models to predict the impact of global climate change (GCC) on the distribution of vegetation at a regional scale| the state of Texas. Then we used habitat preferences for species of rodents in the state to predict how GCC would impact their geographic range and species richness. Our determination of suitable habitats for species of rodents included an average of 98% of capture points| and we found that suitable habitat averaged 62% of the geographic range of species. Size of habitat-corrected range increased an average of 2- to 3-fold under GCC| indicating that rodents were more adaptable to changes in vegetation than were other mammals we studied (e.g.| lagomorphs and insectivores)| whose range decreased| but similar to Chiroptera. whose ranges also increased. Geographic ranges shifted an average of 54% under a warmer| wetter climate and 61% under a warmer| drier climate| resulting in inclusion of an average of 60% new vegetation associations in the ranges under the former scenario and 64% under the latter scenario. The impact of GCC on rodents in Texas was greatest under the warmer| drier climatic scenario. Two species| Oryzomys cousei and Microtus mexicanus| were predicted to go extinct because their suitable habitats did not occur under GCC. These results demonstrated that the type of climate change (warmer| drier or warmer| wetter) and its severity would be important. GCC was predicted to have the greatest impact on rodent distributions in eastern Texas under a scenario of a warmer and wetter climate because forests expanded| whereas the impact would be greatest in western and southern Texas if climate becomes warmer and drier because desert and shrub habitats expanded. Life-history variables (e.g.| habitat type or diet) were correlated with changes in size of range| location| or habitat composition| and reflected broad changes in the relative distribution of vegetation types. Granivores and herbivores used fewer new habitat associations that entered Texas after GCC than did omnivores or insectivores| as did terrestrial rodents compared with fossorial or arboreal rodents. 5597,2001,2,4,Glacial recession in Sorkappland and central Nordenskioldland| Spitsbergen| Svalbard| during the 20th century,Major deglaciation on Spitsbergen has occurred as a result of climate warming since the beginning of the 20th century following the end of the Little Ice Age. The areal extent of glaciers has decreased by ca. 18% in Sorkappland between 1936 and 1991| and by ca. 44% in the Lindstromfjellet-Haberget-Habergnuten ridge region| a mountainous massif of Nordenskioldland| between 1936 and 1995. Recession of glaciers has been accompanied by a decrease in thickness up to 50 m for almost all glaciers since 1936. The equilibrium-line altitude has risen by 100 to 200 m in Sorkappland and by at least 150 m in central Nordenskioldland. Deglaciation in central Nordenskioldland is more than twice that in Sorkappland during the 20th century| which suggests that central Spitsbergen is more sensitive to global warming than is southern Spitsbergen. Spitsbergen's proximity to maritime air masses is probably a more important control for rate of glacial recession than is elevation above sea level or high latitude. 5395,2001,4,4,Glaciers and climate change: Perspectives from oral tradition,In northwestern North America| glaciers figure prominently in both indigenous oral traditions and narratives of geophysical sciences. These perspectives intersect in discussions about global warming| predicted to be extreme at Arctic and Subarctic latitudes and an area of concern for both local people and scientists. Indigenous people in northwestern North America have experienced climate variability associated with the latter phases of the Little Ice Age (approximately 1550-1850). This paper draws on oral traditions passed down from that period| some recorded between 1900 and the early 1950s in coastal Alaska Tlingit communities and others recorded more recently with elders from Yukon First Nations. The narratives concern human travel to the Gulf of Alaska foreshore at the end of the Little Ice Age from the Copper River| from the Alaska panhandle| and from the upper Alsek-Tatshenshini drainage| as well as observations about glacier advances| retreats| and surges. The paper addresses two large policy debates. One concerns the incorporation of local knowledge into scientific research. The second addresses the way in which oral tradition contributes another variety of historical understanding in areas of the world where written documents are relatively recent. Academic debates| whether in science or in history| too often evaluate local expertise as data or evidence| rather than as knowledge or theory that might contribute different perspectives to academic questions. 5451,2001,4,4,Glaciers that speak in tongues and other tales of global warming,This article contains a study of the cumulative global warming since the end of the Little Ice Age in the mid-1800s. It includes the present-day pattern of global ocean circulation and its effect on climate.
3030,2001,5,4,Global climate change and the origin of modern benthic communities in Antarctica,Marine benthic communities living in shallow-water habitats (< 100 m depth) in Antarctica possess characteristics reminiscent of Paleozoic marine communities and modern deep-sea communities. The absence of crabs and sharks| the limited diversity of teleosts and skates| the dominance of slow-moving invertebrates at higher trophic levels| and the occurrence of dense ophiuroid and crinoid populations indicate that skeleton-breaking predation is limited in Antarctica today| as it was worldwide during the Paleozoic and as it is in the deep sea today. The community structure of the antarctic benthos has its evolutionary roots in the Eocene. Data from fossil assemblages at Seymour Island| Antarctic Peninsula suggest that shallow-water communities were similar to communities at lower latitudes until they were affected by global cooling| which accelerated in the late Eocene to early Oligocene. That long-term cooling trend ultimately resulted in the polar climate and peculiar community structure found in Antarctica today. Declining temperatures beginning late In the Eocene are associated with the disappearance of crabs| sharks| and most teleosts. The sudden drop in predation pressure allowed dense ophiuroid and crinoid populations to appear and flourish. These late Eocene echinoderm populations exhibit low frequencies of sublethal damage (regenerating arms)| demonstrating that there was little or no predation from skeleton-breaking fish and decapods. Current scenarios of global climate change include predictions of increased upwelling and consequent cooling in temperate and subtropical upwelling zones. Limited ecological evidence suggests that such cooling could disrupt trophic relationships and favor retrograde community structures in those local areas. 5562,2001,5,4,Global dinoflagellate event associated with the late Paleocene thermal maximum,The late Paleocene thermal maximum| or LPTM (ca. 55 Ma)| represents a geologically brief time interval (similar to 220 k.y.) characterized by profound global warming and associated environmental change. The LPTM is marked by a prominent negative carbon isotope excursion (CIE) interpreted to reflect a massive and abrupt input of C-12-enriched carbon to the ocean-atmosphere reservoir| possibly as a result of catastrophic gas-hydrate release| on time scales equivalent to present-day rates of anthropogenic carbon input. The LPTM corresponds to important changes in the global distribution of biota| including mass extinction of marine benthic organisms| The dinoflagellate cyst record indicates that surfaced-dwelling marine plankton in marginal seas also underwent significant perturbations during the LPTM. We report on the dramatic response of representatives of the genus Apectodinium from two upper Paleocene-lower Eocene sections in the Southern (New Zealand) and Northern (Austria) Hemispheres| where the dinoflagellate records are directly correlated with the CIE| benthic foraminifera extinction event| and calcareous nannofossil zonation. The results indicate that the inception of Apectodinium-dominated assemblages appears to be synchronous on a global scale| and that the event is precisely coincident with the beginning of the LPTM. Apectodinium markedly declined in abundance near the end of the LPTM. This Apectodinium event may be associated with (1) exceptionally high global sea-surface temperatures and/or (2) a significant increase in marginal-marine surface-water productivity| Such a globally synchronous acme of dinoflagellate cysts is unprecedented within the dinoflagellate cyst fossil record. 5603,2001,2,4,Global direct radiative forcing due to multicomponent anthropogenic and natural aerosols,Global simulations of the composition of and direct forcing due to aerosols containing natural and/or anthropogenic sulfate| nitrate| chloride| carbonate| ammonium| sodium| calcium| magnesium| potassium| black carbon| organic matter| silica| ferrous oxide| and aluminum oxide were carried out. Chloride and natural sulfate were found to be the most important natural aerosol constituents in the atmosphere in terms of solar plus thermal-infrared forcing. Sea spray was the most important natural aerosol type| indicating that it should be accounted for in weather and climate calculations. Ammonium was found to have a positive direct forcing| since it reduces water uptake in sulfate-containing solutions; thus| anthropogenic ammonium contributes to global warming. The magnitudes of ammonium and nitrate forcing were smaller than those of chloride or sulfate forcing. When organics were divided into three groups with different assumed UV absorption characteristics| total aerosol direct forcing at the tropopause increased by about +0.03 to +0.05 W m(-2) (direct forcing by organics remained negative)| suggesting that W absorption by organics is a nontrivial component of the global energy balance. Gypsum [CaSO4-2H(2)O]| sal ammoniac [NH4Cl]| halite [NaCl]| halite| and nitrum [KNO3] were estimated to be the most common sulfate-| ammonium-| sodium-| chloride-| and nitrate-containing solid-phase aerosol constituents| respectively| in the global atmosphere. Solid formation in aerosols was found to increase total-aerosol direct forcing by +0.03 to +0.05 W m(-2). Spatial and vertical forcing estimates| sensitivities of forcing to relative humidity and concentration| and estimates of global aerosol liquid water content are given. Modeled aerosol optical properties are compared with satellite and field measurements. 5529,2001,2,4,Global warming and body mass decline in Israeli passerine birds,Global warming may affect the physiology| distributions| phenology and adaptations of plants and animals. In Israel| minimum summer temperatures increased by an average of 0.26 degreesC per decade during the second half of the 20th century. Bergmann's rule predicts that| in warm-blooded animals| races from warm regions are smaller than races from cold regions. Numerous studies have reported general correlations between body mass in fossil animals and independently established palaeoclimatic changes from various parts of the world in accordance with this rule. Using museum specimens| I tested the prediction that the body mass and tarsus length of five resident passerine species in Israel declined between 1950 and 1999. The body mass of four species (the graceful warbler Prinia gracilis| the house sparrow Passer domesticus| the yellow-vented bulbul Pycnonotus xanthopygos and the Sardinian warbler Sylvia melanocephala| but not of the crested lark Galerida cristata) declined significantly during this period. Tarsus length also declined significantly during this period for two species (the graceful warbler and the house sparrow). Body condition (body mass-to-tarsus length ratio) decreased in the Sardinian warbler| the yellow-vented bulbul and the crested lark. It is suggested that the above declines in body mass and tarsus length are due to global warming and also in accordance with Bergmann's rule. The above explanation does not exclude the possibility that other factors| such as a decrease in food availability| contributed to the decline in body mass. These declines may have serious implications for community structure and competition among bird species and may affect the survival of small passerines. 5634,2001,4,5,Global warming and its astro-causes,Looks at the problem of global warming from the viewpoint of wholeness. That is| the problem of global warming will be looked at in a comprehensive study considering several aspects of the cosmos| the Earth| and the phenomenon of life. With such a broad understanding in mind| first analyzes both the disadvantageous and advantageous aspects of the current global warming. Second| compares three typical environmental conditions in which humans have lived. Third| employing the concept of global warming| looks at the myth of how ancient civilizations appeared and disappeared Then| considering our Earth system as an open system travelling in the universe| provides an explanation for the current global warming and for global climate changes. It is expected that the explanation presented can be applied to produce long-term predictions for climate changes.
5638,2001,3,2,Global warming and transport in Brazil - ethanol alternative,This paper deals with the risk of global warming as intensified by the carbon dioxide (CO2) emissions of the transport sector| particularly in gasoline-powered vehicles in Brazil. Car ownership and use are increasing rapidly partly because of very poor public transport quality| which| in turn| is causing higher emission levels Of CO2. In this connection| the use of ethanol in Brazil for the transport sector may prove to be an important alternative| furthering the efforts to stabilise the actual level of gases in the atmosphere. The energy derived from biomass| and in this case| from a renewable| 'clean' source| i.e.| from sugar-cane| has the unquestionable advantage of permitting the almost complete reabsorption of CO2 emitted through the combustion of fuel alcohol. This closed cycle allows| in principle| the increase of the energy supply| essential for economic development| with fewer hazards to the environment. 5407,2001,2,3,Global warming feedbacks on terrestrial carbon uptake under the Intergovernmental Panel on Climate Change (IPCC) emission scenarios,A coupled physical-biogeochemical climate model that includes a dynamic global vegetation model and a representation of a coupled atmosphere-ocean general circulation model is driven by the nonintervention emission scenarios recently developed by the Intergovernmental Panel on Climate Change (IPCC). Atmospheric CO2| carbon sinks| radiative forcing by greenhouse gases (GHGs) and aerosols| changes in the fields of surface-air temperature| precipitation| cloud cover| ocean thermal expansion| and vegetation structure are projected. Up to 2100| atmospheric CO2 increases to 540 ppm for the lowest and to 960 ppm for the highest emission scenario analyzed. Sensitivity analyses suggest an uncertainty in these projections of -10 to +30% for a given emission scenario. Radiative forcing is estimated to increase between 3 and 8 W m(-2) between now and 2100. Simulated warmer conditions in North America and Eurasia affect ecosystem structure: boreal trees expand poleward in high latitudes and are partly replaced by temperate trees and grasses at lower latitudes. The consequences for terrestrial carbon storage depend on the assumed sensitivity of climate to radiative forcing| the sensitivity of soil respiration to temperature| and the rate of increase in radiative forcing by both CO2 and other GHGs. In the most extreme cases| the terrestrial biosphere becomes a source of carbon during the second half of the century. High GHG emissions and high contributions of non-CO2 agents to radiative forcing favor a transient terrestrial carbon source by enhancing warning and the associated release of soil carbon. 5649,2001,2,3,Global warming potentials modified for surface radiative forcing for use in surface energy balance models,The radiative impact of greenhouse gases in warming the Earth varies significantly| depending on whether one considers the forcing at the tropopause or at the surface. Compared to the former| the surface forcing for some greenhouse gases is reduced by the interference of water vapour. Hence| we calculate alternative surface global warming potentials (SGWPs) that are derived from the surface forcing radiation of greenhouse gases for potential use in surface radiative energy balance models (SREBMs). For gases with a large water vapour overlap| the SGWPs are typically 30% smaller than current GWPs; for gases with relatively little overlap| the SGWPs arc larger by more than 33%. These results may be used in conjunction with SREBMs as an additional means of calculating climate change| and may lead to an altered emissions budget compared to that outlined by the current Kyoto agreement. (C) 2001 Royal Meteorological Society 5477,2001,2,3,Global warming signature in observed winter precipitation in Northwestern Europe?,For 40 precipitation series in Northwestern Europe covering the period 1900-1990| the question whether variability of winter (October to March) precipitation on all time scales longer than years can be explained by changes in circulation is investigated. This is done| for each time series| by applying a linear statistical method (multi-regression) linking the winter precipitation to the coefficients of the leading 5 principal components (PCs) of the winter mean mean sea level pressure. Having determined the coefficients| the corresponding hindcasted time series is obtained by applying the model. The interannual variability of winter precipitation is linked to circulation| This has been quantified by the multiple-correlation coefficient between the time series of observed and hindcasted values. Independence between these 2 time series is required for the validation to be meaningful. This is obtained by applying a cross-validation technique. The multiple-correlation coefficient is the largest in the Western Norway region. A comparison is also made between the performance of this standard model and a 'reduced' model based on the link between precipitation and the North Atlantic Oscillation (NAO) index only. This comparison shows that the performance is significantly larger using 5 PCs than using I PC (the NAO)| In contrast| the lowest frequencies are not related to changes in the circulation. This shows up as a systematic positive trend in the difference between the observed and hindcasted precipitation for the majority of series. A Monte Carlo test reveals that this result is unlikely to have occurred by chance. This is interpreted as a change in the physics of the climate system| due to enhanced greenhouse forcing| to changes in sea surface temperatures in connection with some very low frequency mode| or to changes in land use enhancing the hydrological cycle. 5419,2001,4,3,Greenhouse carbon balance of wetlands: methane emission versus carbon sequestration,Carbon fixation under wetland anaerobic soil conditions provides unique conditions for longterm storage of carbon into histosols. However. this carbon sequestration process is intimately linked to methane emission from wetlands. The potential contribution of this emitted methane to the greenhouse effect can be mitigated by the removal of atmospheric CO2 and storage into peat. The balance of CH4 and CO2 exchange can provide an index of a wetland's greenhouse gas (carbon) contribution to the atmosphere. Here. we relate the atmospheric global warming potential of methane (GWP(M)) with annual methane emission carbon dioxide exchange ratio of wetlands ranging from the boreal zone to the near-subtropics| This relationship permits one to determine the greenhouse carbon balance of wetlands by their contribution to or attenuation of the greenhouse effect via CH4 emission or CO2 sink| respectively| We report annual measurements of the relationship between methane emission and net carbon fixation in three wetland ecosystems. The ratio of methane released to annual net carbon fixed varies from 0.05 to 0.20 on a molar basis. Although these wetlands function as a sink for CO2| the 21.8-fold greater infrared absorptivity of CH4 relative to CO2 (GWP(M)) over a relatively short time horizon (20 years) would indicate that the release of methane still contributes to the overall greenhouse effect| As GWP(M) decreases over longer time horizons ( 100 years)| our analyses suggest that the subtropical and temperate wetlands attenuate global warming. and northern wetlands may be perched on the "greenhouse compensation" point. Considering a 500-year time horizon| these wetlands can be regarded as sinks for greenhouse gas warming potential| and thus attenuate the greenhouse warming of the atmosphere. 5577,2001,3,3,Greenhouse gas emissions during cattle feedlot manure composting,The emission of greenhouse gases (GHG) during feedlot manure composting reduces the agronomic value of the final compost and increases the greenhouse effect. A study was conducted to determine whether GHG emissions are affected by composting method. Feedlot cattle manure was composted with two aeration methods-passive (no turning) and active (turned six times). Carbon lost in the forms of CO2 and CH4 was 73.8 and 6.3 kg C Mg-1 manure for the passive aeration treatment and 168.0 and 8.1 kg C Mg-1 manure for the active treatment. The N loss in the form of N2O was 0.11 and 0.19 kg N Mg-1 manure for the passive and active treatments. Fuel consumption to turn and maintain the windrow added a further 4.4 kg C Mg-1 manure for the active aeration treatment. Since CH4 and N2O are 21 and 310 times more harmful than CO2 in their global warming effect| the total GHG emission expressed as CO2-C equivalent was 240.2 and 401.4 kg C Mg-1 manure for passive and active aeration. The Lower emission associated with the passive treatment was mainly due to the incomplete decomposition of manure and a lower gas diffusion rate. In addition| turning affected N transformation and transport in the windrow profile| which contributed to higher N2O emissions for the active aeration treatment. Gas diffusion is an important factor controlling GHG emissions. Higher GHG concentrations in compost windrows do not necessarily mean higher production or emission rates. 5578,2001,2,4,Greenhouse gases in non-oxygenated and artificially oxygenated eutrophied lakes during winter stratification,Concentrations of dissolved methane (CH(4))| carbon dioxide (CO(2))| and nitrous oxide (N(2)O) were measured in the water columns of nonoxygenated and artificially oxygenated| ice-covered eutrophied lakes in the mid-boreal zone in Finland during late winter 1997 and 1999. Sampling was conducted during winter stratification| the critical period for oxygen (O(2)) deficiency in seasonally ice-covered| thermally stratified lakes. Oxygen concentrations were maintained at least at a moderate level throughout the oxygenated water columns| whereas the nonoxygenated columns suffered anoxic hypolimnia. The mean concentrations of dissolved CH(4) exceeding the atmospheric equilibrium were greater in the non-oxygenated water columns (20.6-154 muM) than in the oxygenated ones (0.01-1.41 muM) In contrast| the mean excess CO(2) concentrations varied less between the non-oxygenated and oxygenated sites (0.28-0.47 and 0.25-0.31 mM| respectively). Oxygenated water columns had greater mean excess concentrations of N(2)O (0.018-0.032 muM) than the non-oxygenated ones (0.005-0.024 muM). If the accumulated greenhouse gas stores in the water columns during winter are assumed to be released to the atmosphere during the spring overturn| the global warming potentials (GWP| time horizon 100 yr) of these potential emissions at the non-oxygenated| eutrophic study sites ranged from 177 to 654 g CO(2) equivalent (CO(2-e)) m(-2) compared with 144 to 173 g CO(2-e) m(-2) at the oxygenated sites. The increase in the accumulation of CHI was the main reason for the higher GWP of the non-oxygenated sites. Anthropogenic eutrophication of lake ecosystems can generate increased CHI emissions due to associated O(2) depletion of their sediment and water column. 5520,2001,4,4,Ground surface temperature history at a single site in southern Portugal reconstructed from borehole temperatures,Reliable reconstruction of ground surface temperature (GST) history from borehole temperatures can often be biased by convective heat transport| unrecognized thermal conductivity variations| topography and vegetation changes near borehole locations. To a great extent| all these factors are negligible in the case of a 200-m-deep borehole located near the town of Evora| in southern Portugal. This allows confidence in the interpretation of the borehole temperature versus depth (T-z) profile in terms of the GST changes during the last 150-200 years. To obtain estimates of the GST history| the functional space inversion method was used| which allows incorporation of uncertainties in the data as a priori standard deviations. The method yielded a GST history that indicates warming of about 1 K since the second half of the last century to the middle of the 1990s| with an increase in the last 10-15 years. The results agree with the surface air temperatures (SAT) recorded at the Lisbon meteorological station since 1856| which display a warming trend with an amplitude of about 1 K for the same period. The reduced temperature of the studied T-z profile was used to extend the observed SAT series to times before the instrumental period by estimating the long-term pre-observational mean (POM). The shape of the reduced temperature curve is best fit by POM values that are a few 10ths of a degree Celsius higher than 15.6 degreesC| which is the mean of the SAT series in the period 1856-1900. (C) 2001 Elsevier Science B.V. All rights reserved. 5646,2001,2,4,Growth and behavioral responses to elevated temperatures by juvenile sablefish Anoplopoma fimbria and the interactive role of food availability,Larval and age-0 sablefish Anoplopoma fimbria reside in neustonic waters of the North Pacific during spring and summer. We estimated the potential impacts of elevated surface temperatures on ecological processes of growth| conversion efficiency| and behavior in early juvenile sablefish. Growth experiments tested a wide range of temperatures from 6 to 24(degrees)C| with fish receiving ad libitum or low (3 % body weight d(-1)) rations. With unlimited food| growth increased rapidly as temperature increased to 14(degrees)C| then displayed a more gradual rise to 22 degreesC. Growth rates at the warmer temperatures were among the highest recorded for teleosts| attaining a maximum of 3.3 nun d(-1) in length and a specific growth in weight of 11.8 %. A similar response to temperature was observed at low rations| although at lower overall growth rates. At 24 degreesC| there was a severe decline in growth for both ration levels| and few fish survived the 3 wk experiments. Gross growth efficiency| measured at temperatures of 6 to 22 degreesC| displayed an interactive effect of temperature with ration level consistent with bioenergetic relationship| Conversion peaked at 16 to 20 degreesC for fish receiving ad libitum rations| and at 10 degreesC for fish on restricted rations. Conversion rates of sablefish were comparable to those calculated for a diverse array of fish species| suggesting that the rapid growth rates are driven by high consumption rather than unusually efficient energy transfer. Experiments analyzing sablefish behavior in thermally stratified water columns demonstrated increasing movement into colder water as ration level decreased| in agreement with an energy conserving strategy. Average monthly temperatures within the major nursery areas of neustonic juveniles (north of 40 degreesN) did not exceed 19 degreesC during the last 19 yr. These results suggest that juvenile sablefish are capable of tolerating and thriving at increased temperatures| with the critical caveat that sufficient food resources must be available. Thus| impacts on early life stages exerted by El Nino conditions| oceanographic regime shifts| or climate changes induced by current global warming scenarios are likely to be a consequence of indirect effects on circulation and productivity patterns rather than direct effects of warmer temperatures. However| because the upper thermal limit for growth nearly coincides with the upper limit for survival| exhibiting a sharp demarcation between favorable growth conditions and intolerable temperatures| juvenile sablefish at the southern Limit of their distribution may suffer the direct effects of elevated temperature; recruitment of juveniles to southern populations may become more sporadic if the frequency of warming events increases with climate change. 3049,2001,2,4,Growth responses of Populus tremuloides clones to interacting elevated carbon dioxide and tropospheric ozone,The Intergovernmental Panel of Climate Change (IPCC) has concluded that the greenhouse gases carbon dioxide (CO2) and tropospheric ozone (O-3) are increasing concomitantly globally|| Little is known about the effect of these interacting gases on growth| survival| and productivity of forest ecosystems. In this study we assess the effects of three successive years of exposure to combinations of elevated CO2 and O-3 on growth responses in a five trembling aspen (Populus tremuloides) clonal mixture in a regenerating stand. The experiment is located in Rhinelander| Wisconsin| USA (45 degrees N 89 degreesW) and employs free air carbon dioxide and ozone enrichment (FACE) technology. The aspen stand was exposed to a factorial combination of four treatments consisting of elevated CO2 (560 ppm)| elevated O-3 (episodic exposure-90 mul l(-1) hour(-1))| a combination of elevated CO2 and O-3| and ambient control in 30 m treatment rings with three replications. Our overall results showed that our three growth parameters including height| diameter and volume were increased by elevated CO2| decreased by elevated O-3| and were not significantly different from the ambient control under elevated CO2 + O-3. However| there were significant clonal differences in the responses; all five clones exhibited increased growth with elevated CO2| one clone showed an increase with elevated O-3| and two clones showed an increase over the control with elevated CO2 + O-3| two clones showed a decrease| and one was not significantly different from the control. Notably| there was a significant increase in current terminal shoot dieback with elevated CO2 during the 1999-2000 dormant season. Dieback| was especially prominent in two of the five clones| and was attributed to those clones growing longer into the autumnal season where they were subject to frost. Our results show that elevated O-3 negates expected Positive growth effects of elevated CO2 in Populus tremuloides in the field| and suggest that future climate model predictions should take into account the offsetting effects of elevated O-3 on CO2 enrichment when estimating future growth of trembling aspen stands. (C) 2001 Published by Elsevier Science Ltd. All rights reserved. 5522,2001,4,4,High performance of CO2-temperature gradient chamber newly built for studying the global warming effect on a plant population,To study the effect of global warming concomitant with rising CO2 on plant growth under field-like conditions| a CO2-temperature gradient chamber (CTGC) was created from a standard temperature gradient chamber (TGC). Despite great daily and seasonal changes in ambient air temperature| the gradient of air temperatures was simulated by 5 degreesC warmed conditions at the air outlet| rising at a rare of 1 degreesC at 5 m intervals. Also| CO2 concentrations were linearly increased from the air inlet to the outlet; those at the air inlet and 25 m distance from the air inlet were 372 p.p.m and 756 p.p.m. (doubled)| respectively. The CTGC proved successful in biological experiments conducted through a full growth season in 1998. This apparatus will be useful for understanding plant response to simultaneous changes in CO2 and temperature. Being a combination of a TGC and a CO2 gradient chamber| the improved CTGC allows parameters and validation data sets to both be obtained for models contributing to plant growth| species composition| and global carbon flux analysis. 5429,2001,3,3,Holistic design: key to sustainability in concrete construction,There have been unparalleled advances during the latter half of the last century| to the scientific| engineering and social face of the world| but in that process| the world has also been plunged into several interrelated crises. In the context of the construction industry| these crises can be broadly classified in terms of environment| durability and sustainability. The crises have risen from a number of factors such as technological industrialisation| population growth| worldwide urbanisation| and uncontrolled pollution and creation of waste. There is now the real danger that the massive| indiscriminate and wasteful consumption of the world's material and energy resources may result in extensive global warming that is hard to reverse. The price for this environmental abuse is the rapid deterioration and destruction of the world's infrastructure| water shortages| environmental disasters| and material/structural deterioration by the forces of nature. Every crisis experienced in the world has a direct impact on the construction industry| and since the construction Industry is closely interlinked with energy| resources and environment| irredeemable environmental degradation can only be prevented by sustainable development of the industry which alone can give hope for a better world and better quality of life. This paper advocates a holistic approach to design and construction integrating all aspects from conceptual design to completion and maintenance during service life. 2997,2001,5,3,Holocene paleoclimate data from the Arctic: testing models of global climate change,To evaluate the spatial variability of Arctic climate change during the present interglacial| CAFE Project Members compiled well-dated terrestrial| marine| and ice-core paleoenvironmental records spanning the past 10-12 thousand years (ka). Six tundra biomes of increasing summer temperature requirements were defined based on regionally coherent pollen assemblages. Using a rule-based approach| pollen spectra were converted to tundra| forrst/tundra| or Forest biomes ranked by their average growing season requirements. Marine sea-surface reconstructions were based on proxy data following a similar rule-based approach. From these data-based reconstructions. departures in summer temperatures from modern normals were calculated in 1 ka time slices through the Holocene. To test predictive models| data-based summer temperature reconstructions were compared with general circulation model (GCM) simulations for 10 ka and 6 ka ago. Paleodata and model results both show that warming occurred earlier across Beringia and Asia relative to lands adjacent to the North Atlantic| and that Late Holocene cooling was most apparent in the North Atlantic region. However| the GCM over-predicts the magnitude of Mid-Holocene warming over northern Asia and underestimates the intensification of the North Atlantic drift in the early Holocene. Strong spatial variability in environmental response during the Holocene| despite symmetric (insolation) forcing| suggests that any future changes| whether caused by anthropogenic or natural factors| are unlikely to result in a uniform change across the Arctic| adding additional complexity to forecasts of global impacts. (C) 2001 Elsevier Science Ltd. All rights reserved. 5606,2001,4,4,Homogeneous ice nucleation in aqueous ammonium sulfate aerosol particles,The mechanisms involved in cloud formation affect the resulting cloud radiative properties. Therefore| accurate cloud formation models and related global warming models require freezing data for ammonium sulfate particles| a major constituent of upper tropospheric clouds. Homogeneous ice nucleation in aqueous ammonium sulfate particles has been studied by several laboratory groups; however| there is significant disagreement in the reported data. In the present work| the ice freezing temperatures are measured by sending (NH|)|SO| particles| generated by vapor condensation| through a temperature-controlled flow cell| where ice formation is detected with infrared spectroscopy. To determine possible explanations for disparate results among several laboratories| the experimental methods used in this study are closely examined. Experiments are performed to preclude artifacts| and experimental conditions are varied to develop a complete understanding of processes involved in particle freezing. All experiments produce consistent results. Mass transfer calculations for the aerosol flow tube technique employed in the current study suggest that one frozen particle in 10(4) to 10(6) may scavenge sufficient water vapor from surrounding supercooled aqueous particles such that a single ice particle accumulates enough mass to yield a positive freezing event in the infrared spectrum. This result appears to partially explain the confusing and conflicting results coming from several laboratories employing different experimental methods to observe homogeneous ice nucleation in ammonium sulfate. Six lower limit J (cm(-3) s(-1)) values are determined as 1.1 x 10(6) (233 +/- 1 K| x = 0.013 +/- 0.001)| 1.1 x 10(6) (231 +/- 1 K| x = 0.029 +/- 0.004)| 1.7 x 10(6) (227 +/- 1 K| x = 0.066 +/- 0.015)| 2.8 x 10(6) (226 +/- 1 K| x = 0.071 +/- 0.018)| 8.4 x 10(6) (224 +/- 1 K| x = 0.097 +/- 0.034)| and 8.4 x 10(8) (221 +/- 1 K| x = 0.153 +/- 0.076)| where the associated temperatures and solute mole fraction aqueous compositions (x) are noted in parentheses. 5427,2001,3,3,Hydrogen production. Green algae as a source of energy,Hydrogen gas is thought to be the ideal fuel for a world in which air pollution has been alleviated| global warming has been arrested| and the environment has been protected in an economically sustainable manner. Hydrogen and electricity could team to provide attractive options in transportation and power generation. Interconversion between these two forms of energy suggests on-site utilization of hydrogen to generate electricity| with the electrical power arid serving in energy transportation| distribution utilization| and hydrogen regeneration as needed. A challenging problem in establishing H-2 as a source of energy for the future is the renewable and environmentally friendly generation of large quantities of H-2 gas. Thus| processes that are presently conceptual in nature| or at a developmental stage in the laboratory| need to be encouraged| tested for feasibility| and otherwise applied toward commercialization. 2993,2001,4,2,Identifying global climate change using simple indices,Several simple indices of surface air temperature patterns are used to describe global climate variability and change. The indices include the land-ocean temperature contrast| the hemispheric contrast| the meridional gradient| and the magnitude of the seasonal cycle| as well as the global-mean temperature. The behaviour of the indices is investigated using global observational data for the period 1881-1994 and long control and anthropogenic climate change simulations with two different climate models. The indices represent the key features of the "fingerprint" of greenhouse climate change. For natural climate variations| they contain information independent of the global-mean temperature. The observed trends over the last 40 years in all the indices| except for the hemispheric contrast| are unlikely to have occurred due to natural climate variations and all are consistent with model simulations of anthropogenic climate change. 5432,2001,2,4,Impact of climate warming on Arctic benthic biodiversity: a case study of two Arctic glacial bays,The retreat of Arctic glaciers and a resultant increase in inorganic sedimentation is one of the predicted consequences of global warming. In order to evaluate possible effects of these processes on arctic benthic biodiversity| the fauna of 2 glacial bays| which may be treated as representing the expected phases of the global warming scenario| have been studied. Based on surface water temperature| type of glacier and resulting inorganic sedimentation rates| 'Tikhaia Bay' off Franz Josef Land was chosen to represent an Arctic bay before warming and 'Skoddebukta'| off west Spitsbergen| to represent a similar bay already affected by the predicted climate changes. Macrofauna was collected at 35 stations in Skoddebukta and 44 stations in Tikhaia Bay. Different methods of measuring faunal diversity (number of species| Shannon diversity index| k-dominance plots) were applied to data sets representing the similar habitats sampled in both bays; these showed the fauna of Tikhaia Bay to be more diverse than that in Skoddebukta. This finding is explained by the lower level of disturbance due to inorganic sedimentation and by better trophic conditions in the former location| both of which are linked to the level of glacial activity. This case study leads to the conclusion that one of the consequences of climate warming for Arctic ecosystems will be a decline of benthic biodiversity due to an increase in mineral sedimentation from meltwaters. 3001,2001,2,4,Impact of climatic and other environmental changes on food production and population health in the coming decades,World population will reach an estimated nine billion by 2050. Given this factor and continued economic development in today's low-income countries| the total global demand for food will increase approximately threefold over the coming half-century. Meanwhile| against this background| newly-occurring global environmental changes such as climate change are anticipated to affect food production. Other incipient large-scale environmental changes likely to affect food production include stratospheric O-3 depletion| the accelerating loss of biodiversity (with knock-on effects on crop and livestock pest species) and the perturbation of several of the great elemental cycles of N and S. The ways in which these various environmental influences affect the production of food (crops and livestock on land| and wild and cultivated fisheries) are complex and interactive. Uncertainties therefore persist about how global climate change is likely to affect world and regional food production. On balance| recent modelling-based estimates indicate that| in the medium to longer term| if not over the next several decades| climate change is likely to affect crop yields adversely| especially in food-insecure regions. The prospect of increased climatic variability further increases the risks to future food production. Given these possible though uncertain adverse impacts of climatic acid other environmental changes on world food production| there is a need to apply the Precautionary Principle. There are finite| and increasingly evident| limits to agro-ecosystems and to wild fisheries. Our capacity to maintain food supplies for an increasingly large and increasingly expectant world population will depend on maximising the efficiency and sustainability of production methods| incorporating socially-beneficial genetic biotechnologies| and taking pre-emptive action to minimise detrimental ecologically-damaging global environmental changes. 5653,2001,2,2,Impact of global warming on the interannual and interdecadal climate modes in a coupled GCM,In this study| we investigated the impact of global warming on the variabilities of large-scale interannual and interdecadal climate modes and teleconnection patterns with two long-term integrations of the coupled general circulation model of ECHAM4/OPYC3 at the Max-Planck-Institute for Meteorology| Hamburg. One is the control (CTRL) run with fixed present-day; concentrations of greenhouse gases. The other experiment is a simulation of transient greenhouse warming| named GHG run. In the GHG run the averaged geopotential height at 500 hPa is increased significantly| and a negative phase of the Pacific/North American (PNA) teleconnection-like distribution pattern is intensified. The standard deviation over the tropics thigh latitudes) is enhanced (reduced) on the interdecadal time scales and reduced (enhanced) on the interannual time scales in the GHG run. Except for an interdecadal mode related to the Southern Oscillation (SO) in the GHG run| the spatial variation patterns are similar for different (interannual + interdecadal| interannual| and interdecadal) time scales in the GHG and CTRL runs. Spatial distributions of the teleconnection patterns on the interannual and interdecadal time scales in the GHG run are also similar to those in the CTRL run. But some teleconnection patterns show linear trends and changes of variances and frequencies in the GHG run. Apart from the positive linear trend of the SO| the interdecadal modulation to the El Nino/SO cycle is enhanced during the GHG 2040 similar to 2099. This is the result of an enhancement of the Walker circulation during that period. La Nino events intensify and El Nino events relatively weaken during the GHG 2070 similar to 2090. It is interesting to note that with increasing greenhouse gas concentrations the relation between the SO and the PNA pattern is reversed significantly from a negative to a positive correlation on the interdecadal time scales and weakened on the interannual time scales. This suggests that the increase of the greenhouse gas concentrations will trigger the nonstationary correlation between the SO and the PNA pattern both on the interdecadal and interannual time scales. 5531,2001,2,4,Impact of global warming on the tree species composition of boreal forests in Finland and effects on emissions of isoprenoids,This study aims to identify how climate change may influence total emissions of monoterpene and isoprene from boreal forest canopies. The whole of Finland is assumed to experience an annual mean temperature (T) increase of 4 degreesC and a precipitation increase of 10% by the year 2100. This will increase forest resources throughout the country. At the same time| the proportions of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) in southern Finland (60 degrees less than or equal to latitude <65Water from the Missouri River Basin is used for multiple purposes. The climatic change of doubling the atmospheric carbon dioxide may produce dramatic water yield changes across the basin. Estimated changes in basin water yield from doubled CO2 climate were simulated using a Regional Climate Model (RegCM) and a physically based rainfall-runoff model. RegCM output from a five-year| equilibrium climate simulation at twice present CO2 levels was compared to a similar present-day climate run to extract monthly changes in meteorologic variables needed by the hydrologic model. These changes| simulated on a 50-km grid| were matched at a commensurate scale to the 310 subbasins in the rainfall-runoff model climate change impact analysis. The Soil and Water Assessment Tool (SWAT) rainfall-runoff model was used in this study. The climate changes were applied to the 1965 to 1989 historic period. Overall water yield at the mouth of the Basin decreased by 10 to 20 percent during spring and summer months| but increased during fall and winter. Yields generally decreased in the southern portions of the basin but increased in the northern reaches. Northern subbasin yields increased up to 80 percent: equivalent to 1.3 cm of runoff on an annual basis.
3036,2001,2,4,Impacts of extreme climatic events on competition during grassland invasions,Phytometers of five C3 and five C4 species were transplanted into three different grasslands to study the effects of extreme climatic events on community invasibility and competition. Single extreme heating (eight hours at 52.5 degreesC) and rainfall (the equivalent of 100 mm) events in factorial combinations were superimposed on the grassland communities. A novel technique involving portable computer-controlled chambers was used to create the heating events. In order to generate predictions of response to the extreme climatic events| the 10 phytometer species were categorized con the basis of 12 key plant functional traits. Using principal component analysis| two functional types (FTs) were identified as most likely to be advantaged (FT1| fast-growing C4 annuals) and disadvantaged (FT2| slower-growing C3 perennials) by an extreme climatic event. Competition between the resident vegetation and FT1 plus other C4 phytometers was consistently more intense within the exclusively C3 community compared to the dry C3/C4 community or moist C3/C4 community. The single extreme heating event had the greatest impact on competition| lowering the intensity of competition between the phytometers and resident vegetation. Our results indicate that competition is highly important in limiting the invasion of C3 grasslands by C4 species. The FT1 and FT2 responses confirmed predictions based on plant functional traits| whether growing as phytometers or as part of the resident vegetation. Future increases in climatic variability and the incidence of extreme climatic events are expected to suppress C3 competitive dominance and promote invasion of C4 species| in particular| the FT1 species. 5663,2001,3,4,In vitro techniques for genomic alteration in rice plants,Because of the explosive increase in world population| a sufficient food supply must be achieved by varietal improvement in the major cereal crops including rice. It is expected that new in vitro techniques in combination with conventional breeding methods may effectively raise the yield potential. On the other hand| there are many environmental problems to be solved world-wide such as| global warming| environmental pollution| ecological destruction| reduction in water supplies and so on. Therefore| it is necessary to rapidly develop new varieties for the future combining of higher yield potential with excellent grain quality| and resistance to both biotic and abiotic stresses for the promotion of sustainable agriculture. Although many efforts have been made to introduce useful traits from wild species to cultivated rice via hybridization| it is still difficult to overcome breeding barriers such as cross incompatibility and hybrid sterility and inviability in practical breeding. Now in vitro techniques are going to make it possible to use genetic manipulation and cell culture and fusion techniques to speed up the breeding process. For sustainable agriculture| it is important to utilize the useful genes from alien species. For this purpose| asymmetric protoplast fusions have already been used successfully to transfer disease resistance in Brassica napus. In this experiment| a high level of resistance to the rice blast disease was transferred from wild species through asymmetric fusions. It is also noted that manipulation of cytoplasmic genomes is possible through asymmetric fusions as shown in the induction of new cytoplasmic male sterility (CMS). 5487,2001,2,4,Increased understanding of nutrient immobilization in soil organic matter is critical for predicting the carbon sink strength of forest ecosystems over the next 100 years,The terrestrial biosphere is currently thought to be a significant sink for atmospheric carbon (C). However| the future course of this sink under rising [CO2] and temperature is uncertain. Some contrasting possibilities that have been suggested are: that the sink is currently increasing through CO2 fertilization of plant growth but will decline over the next few decades because Of CO2 saturation and soil nutrient constraints; that the sink will continue to increase over the next century because rising temperature will stimulate the release of plant-available soil nitrogen (N) through increased soil decomposition; that| alternatively| the sink will not be sustained because the additional soil N released will be immobilized in the soil rather than taken up by plants; or that the sink will soon become negative because loss of soil C through temperature stimulation of soil respiration will override any CO2 or temperature stimulation of plant growth. Soil N immobilization is thus a key process; however| it remains poorly understood. In this paper we use a forest ecosystem model of plant-soil C and N dynamics to gauge the importance of this uncertainty for predictions of the future C sink of forests under rising [CO2] and temperature. We characterize soil N immobilization by the degree of variability of soil N:C ratios assumed in the model. We show that the modeled C sink of a stand of Norway spruce (Picea abies (L.) Karst.) in northern Sweden is highly sensitive to this assumption. Under increasing temperature| the model predicts a strong C sink when soil N:C is inflexible| but a greatly reduced C sink when soil N:C is allowed to vary. In complete contrast| increasing atmospheric [CO2] leads to a much stronger C sink when soil N:C is variable. When both temperature and [CO2] increase| the C sink strength is relatively insensitive to variability in soil N:C; significantly| however| with inflexible soil N:C the C sink is primarily a temperature response whereas with variable soil N:C| it is a combined temperature-CO2 response. Simulations with gradual increases of temperature and [CO2] indicate a sustained C sink over the next 100 years| in contrast to recent claims that the C sink will decline over the next few decades. Nevertheless| in using a relatively simple model| our primary aim is not to make precise predictions of the C sink over the next 100 years| but rather to highlight key areas of model uncertainty requiring further experimental clarification. Here we show that improved understanding of the processes underlying soil N immobilization is essential if we are to predict the future course of the forest carbon sink. 2960,2001,2,4,Indicators of UV exposure in corals and their relevance to global climate change and coral bleaching,A compelling aspect of the deterioration of coral reefs is the phenomenon of coral bleaching. Through interactions with other factors such as sedimentation| pollution| and bacterial infection| bleaching can impact large areas of a reef with limited recovery| and it might be induced by a variety of stressors including temperature and salinity extremes| and ultraviolet light. Under conditions of ocean warming| often associated with calm and stratified waters| photobleaching of UV-absorbing chromophoric dissolved organic matter (CDOM) is increased| and penetration of both UV-B. and UV-A is greatly enhanced. Indices of UV-specific effects in coral tissue are needed to test whether UV increases| associated with global climate change| are harmful to corals. To address this challenge| we have evaluated UV-specific effects in corals and have characterized factors that alter penetration of UV radiation over coral reefs. An immunoblotting assay was developed to examine UV-specific lesions (thymine dimers) in coral and zooxanthellae DNA. We observed dose-dependent increases of thymine dimers in coral (Porites porites var porites) exposed to artificial solar irradiance in a solar simulator| although effects were not strictly proportional. UV measurements were made in July 1999 at Eastern Sambo reef and nearby sites| including profiling along transects from reef to shore. Results of these analyses indicate that the coral at Eastern Sambo reef (at 34 meters) were receiving UV-B radiation that was equivalent to 25 to 30% of surface UV irradiance. However| the water just inside the reef in Hawk Channel (located closer to land) was considerably more opaque to UV. This water photobleached with loss of UV absorbance and fluorescence when it was exposed to simulated solar radiation. These results indicate that photobleaching of the DOM and transport of near-shore water out over the reefs might play a key role in controlling UV penetration to the reef surface. 5560,2001,2,4,Influence of high temperature on end-of-season tundra CO2 exchange,The high-arctic terrestrial environment is generally recognized as one of the world's most sensitive areas with regard to global warming. In this study| we examined the influence of an isolated warm period on net ecosystem carbon dioxide (CO2) exchange at high latitude during autumn. Using the Free Air Temperature Increase (FATI) technique| we manipulated air| soil| and vegetation temperatures in late August in a tundra site at Zackenberg in the National Park of North and East Greenland (74 degreesN 21 degreesW). The consequences for gross canopy photosynthesis| canopy respiration| and belowground respiration of increasing these temperatures by approximately 2.5 degreesC were determined with closed dynamic CO2 exchange systems. Under current temperatures| the ecosystem acted as a net CO2 source| releasing 19 g CO2-C m(-2) over the 14-day study period. Warm soils and senescing vegetation in autumn were unequivocally responsible for this efflux. Heating enhanced CO2 efflux to 29 g CO2-C m(-2). This effect was attributed to a 39% increase in belowground respiration| which was the main component of the carbon (C) budget. Gross photosynthesis| on the other hand| was not affected significantly by the simulated warming. Although the aftereffects of an isolated warm period on the C balance in early winter could be significant| simulations with a simple C budget model suggest that soil carbon pools are not affected to a great extent by such a climatic disturbance. The influence on atmospheric carbon| however| appears to be significant. 5483,2001,3,4,Influence of the nitrification inhibitor 3|4-dimethylpyrazole phosphate (DMPP) in comparison to dicyandiamide (DCD) on nitrous oxide emissions| carbon dioxide fluxes and methane oxidation during 3 years of repeated application in field experiments,In a 3-year field experiment| the effect of the nitrification inhibitor (NI) 3|4-dimethylpyrazole phosphate (DMPP) on the release of N2O| CO2 and on CH4 oxidation| was examined in comparison to that of dicyandiamide (DCD) on N-fertilized and unfertilized experimental sites. Soil samples were analysed simultaneously for the concentrations of N2O retained in the soil body. NH4+| NO2-| NO3-| and for the degradation kinetics of DMPP as well as DCD. DMPP decreased the release of N2O on fertilized plots by 41% (1997)| 47% (1998) and 53% (1999) (on average by 49%) while DCD reduced N2O emissions by 30% (1997) 22% (1998) and 29% (1999) (on average by 26%). In addition| the NIs seemed to decrease the CO2 emissions of each fertilized treatment. DCD reduced the release of CO2 by an average of 7% for the 3 years (non-fertilized 10%)| and DMPP reduced it by an average of up to 28% (non-fertilized 29%). Furthermore| both NIs failed to affect CH4 oxidation negatively. The plots that received either DCD or DMPP even seemed to function as enhanced sinks for atmospheric CH4. DMPP apparently stimulated CH4 oxidation of N-fertilized plots by ca 28% in comparison to the control. In total| DCD and DMPP reduced the global warming potential of N-fertilized plots by 7% and 30%| respectively. Further| DCD and DMPP diminished the amount of N2O retained in the soil by 52% and 61%| respectively. The concentrations of NH4+ remained unaffected by both NIs| whereas the amounts of NO2- diminished in the plots treated with DCD by 25% and with DMPP by 20%. In both NI treatments NO3- concentrations in the soil were 23% lower than in the control. DMPP and DCD did not affect the yields of summer barley| maize and winter wheat significantly. DCD was mineralized more rapidly than DMPP. 5615,2001,3,3,Interactions and coupling between emissions of methane and nitrous oxide from animal husbandry,The gases methane (CH(4)) and nitrous oxide (N(2)O) contribute to global warming| while N(2)O also affects the ozone layer. Sources of greenhouse gas emissions in animal husbandry include animals| animal houses (indoor storage of animal excreta)| outdoor storage| manure and slurry treatment (e.g.| composting| anaerobic treatment)| land application and chemical fertilisers. Although in many countries emphasis is put on reduction of environmental pollution by nutrients| ammonia emission and odour nuisance| reduction of the emission of greenhouse gases will become equally important in the near future to meet integrated sustainability criteria (1997 Kyoto protocol). Emissions of greenhouse gases differ in origin. Methane from animal husbandry is for a large part endogenous| and may be hard to reduce in intensive animal production. Methane emission reduction strategies should focus on its use as fuel or preventing its formation| mainly during on-farm storage (indoor| outside) or treatment through control of critical processes (degradation of organic matter) and critical factors (e.g.| temperature). Nitrous oxide is mainly produced during the aerobic storage and treatment of animal excreta| as well as after land spreading. As N(2)O basically is an intermediate product of complex biochemical processes (nitrification| denitrification)| optimal process conditions are the key issues in N(2)O emission reduction strategies from animal husbandry. 5445,2001,2,3,Interactive effects of increased temperature and CO(2) on the growth of Quercus myrsinaefolia saplings,The interactive effects of increased temperature and CO(2) enrichment on the growth of 2-year-old saplings of Quercus myrsinaefolia| an evergreen broad-leaved oak| were studied throughout an entire year in the vicinity of their northernmost distribution. Saplings were grown under different conditions in two chambers: (1) a temperature gradient chamber at ambient temperature| 3 and 5 degreesC warmer condition's with an ambient CO(2) concentration| and (2) in a CO(2) temperature gradient chamber at 3 degreesC warmer conditions|with 1.5 times the normal CO(2) concentration| and 5 degreesC warmer conditions with doubled CO(2) concentration. The 3 and 5 degreesC warmer conditions enhanced the relative growth rate during almost the entire year| producing 53 and 47% increases in annual biomass production| 27 and 44% enhancement of root growth during shoot dormancy and 3 and 5 week prolongation of the shoot growing period| respectively. However| a daily mean air temperature exceeding 30 degreesC under the 5 degreesC warmer condition caused a marked reduction in net assimilation rate (NAR) from July to September. The CO(2) enrichment further enhanced the positive effects of warming in spring and the resulting increases in NAR almost completely compensated for the negative effect of warming during summer. From autumn to winter| attenuation of the effects of CO(2) was compensated by the increased sink strength produced by the warming. The annual biomass production was more than doubled by the combination of temperature elevation and CO(2) enrichment. 3047,2001,3,4,Intertemporal social choice and climate stabilization,This paper examines the implications of alternative approaches to intertemporal social choice in a numerically calibrated model of interactions between global climate change and the world economy. Under cost-benefit analysis| relatively modest steps towards greenhouse gas emissions abatement are justified as economically efficient. Under classical utilitarianism and the precautionary principle. in contrast| aggressive steps towards climate stabilization emerge as socially optimal. The paper reviews the value judgements that support each of these normative approaches| arguing that the precautionary principle is most closely tied to the goals and objectives of the Framework Convention on Climate Change. 5535,2001,2,3,Investigating the haze transport from 1997 biomass burning in Southeast Asia: its impact upon Singapore,The 1997 Indonesia forest fires was an environmental disaster of exceptional proportions. Such a disaster caused massive transboundary air pollution and indiscriminate destruction of biodiversity in the world. The immediate consequence of the fires was the production of large amounts of haze in the region| causing visibility and health problems within Southeast Asia. Furthermore| fires of these magnitudes are potential contributors to global warming and climate change due to the emission of large amounts of greenhouse gases and other pyrogenic products. The long-range transport of fire-related haze in the region is investigated using trajectories from the CSIRO Division of Atmospheric Research Limited Area Model(DARLAM). Emission scenarios were constructed for hotspot areas in Sumatra and Kalimantan For the months of September and October 1997 to determine the period and fire locations most critical to Singapore. This study also examines some transport issues raised from field observations. Results show that fires in the coastal areas of southeast Sumatra and southwest Kalimantan can be potential contributors to transboundary air pollution in Singapore. Singapore was directly affected by haze from these areas whereas Kuala Lumpur was heavily affected by the haze coming From Sumatra. In most cases| Singapore was more affected by fires from Kalimantan than was Kuala Lumpur. This was mainly a result of the shifting of monsoons. The transition of monsoons resulted in weaker low-level winds and shifted convergence zones near to the southeast of Peninsular Malaysia. In addition to severe drought and massive fire activity in 1997| the timing of the monsoon transition has a strong influence on haze transport in the region. (C) 2001 Elsevier Science Ltd. All rights reserved. 3039,2001,4,4,Is Southern Ocean organic carbon and biogenic silica export enhanced by iron-stimulated increases in biological production? Sediment trap results from SOIREE,During the first in situ| mesoscale iron fertilisation experiment conducted in the Southern Ocean (SOIREE| 61 degreesS 140 degreesE| austral summer| February 10-22| 1999)| export processes beneath an iron-stimulated phytoplankton bloom were monitored using free-drifting sediment traps. Duplicated arrays were deployed during days T7-9 and T11-13 inside the iron-fertilised patch with single "control" arrays deployed outside the patch on days T0-2 and T11-13. Average total mass and chlorophyll a flux at 110 m approximately doubled between TO-2 and T7-9 (395-735 mg dry weight m(-2) d(-1) and 50-110 mug chl a m(-2) d(-1)| respectively)| while particulate organic carbon (POC)| particulate organic nitrogen (PON) and phaeopigment fluxes increased only slightly (15-30%) and biogenic silica (BSi) fluxes were essentially constant (90-100mgm(-2)d(-1)). Inside the patch between T7-9 and T11-13| mass flux remained at about 735-745 mg m(-2) d(-1) while other flux components increased by 30-40%. Mean POC and silica fluxes inside the patch at T11-13 were about 185 and 150mgm(-2)d(-1)| respectively| compared with 80 and 90 mgm(-2) d(-1) measured outside. However| flux variations of > 50% between the two "control" deployments at TO-2 and T11-13 confounded the trapping experiment. POC and PON fluxes at deep traps were typically 30-50% of those at shallow traps| whereas total mass and silica fluxes at 310 m were generally 70- > 90% of the flux at 110 m| indicating substantial remineralisation of POC| relative to silica| over the top 300 m of the water column. As also suggested by other biogeochemical proxies (Th-234| delta C-13)| POC and biogenic silica export from the SOIREE patch did not increase measurably in response to iron-stimulated increases in primary production and a floristic shift to large| heavily silicified| chain-forming diatoms. The temporal decoupling between new and export production was accompanied by considerable algal accumulation in the mixed layer| reductions in phytoplankton sinking rates inside the patch| and low levels of mesozooplankton grazing during SOIREE. Since elevated satellite-derived algal concentrations persisted near the experimental site for 30-45 d after SOIREE| a conservative estimate of potential total nux from the bloom is calculated (6-9 g C m(-2)). Considerable logistical constraints must be overcome| however| in order to quantify the magnitude of carbon export from iron-mediated blooms at high southern latitudes before we can establish links between Southern Ocean productivity and global climate change| as encapsulated in the "Iron Hypothesis". (C) 2001 Elsevier Science Ltd. All rights reserved. 5473,2001,2,4,Isolation (with enrichment) and characterization of trinucleotide microsatellites from Phlebotomus perniciosus| a vector of Leishmania infantum,Mitochondrial DNA characterization of the sandfly Phlebotomus perniciosus has not resolved the population structure of its Iberian lineage. For this purpose| four AGC- and seven AGG-class microsatellite loci were characterized| after their isolation using Biotin-Avidin enrichment and the screening of plasmid libraries by polymerase chain reaction. Of the five polymorphic loci analysed in four Spanish populations| four showed patterns of allele diversity consistent with migration from a southern Ice Age refuge. Estimates of the historical migration rates of P. perniciosus will help to predict the effects of global warming on its range and that of Leishmania infantum| the parasitic protozoan it transmits. 5458,2001,4,4,Isotonic regression: Another look at the changepoint problem,A test based on isotonic regression is developed for monotonic trends in short range dependent sequences and is applied to Argentina rainfall data and global warming data. This test provides another perspective for changepoint problems. The isotonic test is shown to be more powerful than some existing tests for trend. 5396,2001,5,4,Lake-expanding events in the Tibetan Plateau since 40 kaBP,Since 40 kaBP| the current endorheism on the Tibetan Plateau had experienced at least four lake-expanding events| at 40-28 kaBP| 19-15 kaBP| 13-11 kaBP| 9.0-5.0 kaBP| respectively. The 40-28 kaBP and 9.0-5.0 kaBP lake-expanding events| corresponding to the global warming periods| were mainly determined by the abundant summer monsoon rainfall brought by strong Indian monsoon| aroused by enhanced solar radiation at earth orbital precessional cycle. The 40-28 kaBP lake-expanding event| also called the great lake period or the pan-lake period| for several great lake groups had come into being by the interconnection of the presently isolated and closed lake catchments. The total lake area over the Tibetan Plateau was estimated at least up to 150000 km(2)| 3.8 times of the present| and the lake supply coefficients were about 3-10. The 9.0-5.0 kaBP lake-expanding| with a total lake area of 68000 km(2)| less than the above mentioned reflected the Indian monsoon rainfall less than that of 40-28 kaBP. The expanded lakes at 19-15 kaBP and 13-11 kaBP| distributed in these basins with more or less existing glacial| indicated plenty of glacial meltwater discharged to balance evaporation on expansive lake surface. At the same time| the enhanced precipitation by the westerlies at 19-15 kaBP and by Indian monsoon at 13-11 kaBP plays an important role in maintaining the high lake level. Heinrich events greatly affected the evolution of climate system over the Tibetan Plateau| and thus gave a clear boundary of the high lake level change in the late Quaternary. 2967,2001,2,4,Land loss at the Venezuelan coast due to sea level rise,Some of the effects of the global climate change comprise impacts on human health| agricultural production and plagues| sea level rise| patterns of precipitation and evaporation| and storms. The objective of this study is to assess the potential land loss upon a sea level rise of 0.5m in two Venezuelan coastal sectors: Cabo Codera-Parque Nacional Laguna de Tacarigua and Barcelona-Puerto La-Cruz-Guanta. It was estimated that the first one of the two sectors is more vulnerable to land loss due to erosion| while losses due to inundation are not significantly higher for any of the two areas. Impacts affect mostly urban areas| tourist infrastructure and coastal wetlands. In the vulnerability analysis of sea level impact| the response options evaluated would generate a very high cost for the country. It is proposed that vulnerability analysis to sea level rise be incorporated as part of the coastal zones planning and management process. 5614,2001,2,4,Lapse rate changes in northern England,Most GCMs indicate distinct elevational signals in temperature response to global warning| both in the free-air and at the surface| although modelled changes are spatially variable| in magnitude and in sign. In this study| daily climate observations (1968-1995) from two sites in northern England| representative of upland and lowland environments| are used to derive a regionally representative lapse rate. The lapse rates of daily maximum and minimum temperatures show strong seasonal and diurnal patterns. and relationships with synoptic conditions| classified using the Lamb classification. Synoptic types with westerly components show the most rapid decrease of temperature with elevation. Lapse rates are also steeper when there is a strong altitudinal increase in cloud cover| decrease in sunshine duration| or strong wind shear. Lapse rates are becoming steeper by day but weaker at night (p < 0.1%). Such changes occur within most synoptic types| and there are not many statistically significant changes in relative airflow frequencies. Weak relationships exist between measurements of the NAO and lapse rates| but within airflow-type modification is also influential| being connected with changes in SSTs to the west of the U.K. Correlations between mean monthly lapse rates and SSTs vary spatially. Low SSTs in the north and high SSTs in the south of the region encourage steep daytime lapse rates| implying a steeper lapse rate under a stronger meridional temperature gradient. At night the opposite relationship holds. Over time there has been strengthening in the meridional SST gradient to the west of the U.K.| confirmed by analysis of a SST data set from CRU (1968-1995). This correlates with the increased diurnal lapse rate signal. Changes in upland temperatures in northern England are dependent on variable lapse rate modification for individual synoptic types| in this case influenced by upwind SSTs and their meridional gradient. Thus different mountain ranges will react in contrasting ways to global warming. 2998,2001,2,4,Large scale Antarctic features captured by multi-frequency scanning microwave radiometer on-board OCEANSAT-1,This paper discusses the features observed over the Antarctic in the passive microwave emission region by the multi-frequency scanning microwave radiometer (MSMR) instrument on-board the Indian remote sensing satellite IRS-P4| now called OCEANSAT-1| Brightness temperature images produced from MSMR show a clear distinction between open water and sea-ice-covered regions. It is also possible to differentiate several levels of ice concentration in the Antarctic Circumpolar Ocean. A number of land features like the Trans-Antarctic Mountain Ranges| part of Gamburtsev sub-glacial mountains| Wilkes and Aurora sub-glacial basins| etc| can be demarcated as well| The consistent quality and regular availability of MSMR data since June 1999 serve as a very useful tool in all-weather day-and-night monitoring of the Antarctic region. MSMR data used in continuation of ESMR| SMMR and SSM/I data| would prove valuable in the study of long-term changes in the polar cryosphere associated with global climate change. 5627,2001,2,4,Late 18th century drought-induced sand dune activity| Great Sand Hills| Saskatchewan,Geomorphic evidence and optical ages from seven locations indicate that widespread dune activity occurred within the last 200 years in the Great Sand Hills region of southwestern Saskatchewan. Optical ages (n = 36) define an interval of dune activity bracketed by the earliest age of back ridges in the Seward sand hills (185 +/- 8 years) and the average age of stabilized dune heads (about 105 years). During this interval| parabolic dunes were active in all areas studied. These ages indicate that the most recent interval of activity was initiated about AD 1800| and continued at a level higher than present for approximately 80 years. The most likely cause of dune activation was lower-than-average precipitation (relative to 1960-1991 values) through the 1700s| culminating in drought in the late 1700s| as evidenced in dendroclimatic records from the Cypress Hills and from the Rocky Mountain foothills. Dunes affected by such climatically induced regional activity require many decades to restabilize. Historical observations show that dunes in this area have been restabilizing throughout the 20th century. For the southern Canadian Prairies| a region with serious concerns about the implications of global warming| this study highlights the sensitivity of sand dunes to drought and cumulative moisture stress. 5586,2001,3,3,Life cycle assessment estimation for eco-management of co-generation systems,A LCA (life cycle assessment) scheme for any industrial activity system is introduced to estimate the quantitative loan on the environment with the aid of the NETS (numerical environment total standard) method proposed by the authors as a numerical measure. Two kinds of environmental loads respecting fossil fuel depletion as input resources to the system and global warming due to CO2 emission as output are taken into account in the present eco-criterion| in which the total eco-load (EcL) value is calculated from the summation of respective environmental load factors on the whole process in a life cycle of the system. This NETS method is applied to eco-management co-generation systems| in which a computer-aided output navigator proceeds the LCA estimation|with ICON and Q&A communication. An operation scheme most friendly to the environment with a minimum EcL value| i.e.| an eco-operation scheme| is derived from the optimization theory. 5667,2001,3,4,Life cycle assessment of different reuse percentages for glass beer bottles,Life cycle assessment (LCA) is increasingly becoming an important tool for ecological evaluation of products or processes. In this study the environmental impacts associated with the returnable and the non-returnable glass beer bottles were assessed in order to compare different reuse percentages. The inventory analysis is performed with data obtained from two Portuguese companies (a glass bottles producer and a brewery) and completed with the BUWAL database. It includes all operations associated with the bottles' manufacture| the brewery and the wastewater treatment plant. The environmental impact assessment considers both the potential ecological and ecotoxicological effects of the emissions. The environmental impact categories included and discussed in this study are the contribution to ecological and human health| global warming| stratospheric ozone depletion| acidification| eutrophication and photochemical ozone creation. The first category is divided into three subcategories that are human toxicity| critical air volume and critical water volume. This study was performed for several reuse percentages and returnable bottle cycles| and is comprised of a sensitivity analysis. The general output is that the relative importance of the impacts associated with the use of returnable and/or non-returnable bottles depends on the number of cycles performed by the returnable bottles. According to the impact index defined in this study| the most significant impacts are the eutrophication and the final solid wastes generated| and the least significant impact is the ozone depletion. 5509,2001,3,3,Life cycle assessment of eco-designed residential gas appliances,LCA (Life Cycle Assessment) has been conducted on residential gas appliances designed based on the eco-design guide that city gas suppliers planned| for certifying validity and clarifying problems of it. In other words| life cycle inventories of these gas appliances were generated| and Life Cycle Impact Assessment (LCIA) was carried out. Five environmental impact categories were considered: "Resources Consumption"| "Global Warming"| "Acidification"| "Energy Consumption"| and "Solid Waste". The following results were obtained. Components of residential gas appliances are mostly iron and nonferrous metals. The residential gas appliances designed to be light give lower environmental loads at the production stage than general gas appliances| but occasionally the environmental loads are increased. This suggests there is the trade-off relation between the designing for lightness and the environmental loads depending on the material. It is necessary to develop the optimizing techniques to minimize environment loads when the material is selected. It is necessary to develop a new LCA methodology by which the change of the inventory as time passes is considered with the product that has large environmental loads at the using stage. 3022,2001,2,4,Light regime in an Arctic fiord: a study related to stratospheric ozone depletion as a basis for determination of UV effects on algal growth,Solar radiation as a primary abiotic factor affecting productivity of seaweeds was monitored in the Arctic Kongsfjord on Spitsbergen from 1996 to 1998. The radiation was measured in air and underwater| with special emphasis on the UV-B (ultraviolet B| 280-320 nm) radiation| which may increase under conditions of stratospheric ozone depletion. The recorded irradiances were related to ozone concentrations measured concurrently in the atmosphere above the Kongsfjord with a balloon-carried ozone probe and by TOMS satellite. For comparison| an ozone index (a spectroradiometrically determined irradiance of a wavelength dependent on ozone concentration| standardized to a non-affected wavelength) was used to indicate the total ozone concentration present in the atmosphere. Weather conditions and| hence| solar irradiance measured at ground level were seldom stable throughout the study. UV-B irradiation was clearly dependent on the actual ozone concentration in the atmosphere with a maximal fluence rate of downward irradiance of 0.27 W m(-2) on the ground and a maximal daily fluence (radiation exposure) of 23.3 kJ m(-2) To characterize the water body| the light transmittance| temperature and salinity were monitored at two different locations: (1) at a sheltered shallow-water bay and (2) at a wave-exposed| deep-water location within the Kongsfjord. During the clearest water conditions in spring| the vertical attenuation coefficient (K-d) for photosynthetically active radiation (PAR) was 0.12 m(-1) and for UV-B 0.34 m(-1). In spring| coinciding with low temperatures and clear water conditions| the harmful UV radiation penetrated deeply into the water column and the threshold irradiance negatively affecting primary plant productivity was still found at about 5-6 m depth. The water body in spring was characterized as a Jerlov coastal water type 1. With increasing temperature in summer| snow layers and glacier ice melted| resulting in a high discharge of turbid fresh water into the fjord. This caused a stratification in the optical features| the salinity and temperature of the water body. During melt-water input| a turbid freshwater layer was formed above the more dense sea water. Under these conditions| light attenuation was stronger than defined for a Jerlov coastal water type 9. Solar radiation was strongly attenuated in the first few metres of the water column. Consequently| organisms in deeper water are protected against harmful UV-B radiation. In the surface water| turbidity decreased when rising tide caused an advection of clearer oceanic water. In the course of the summer season| salinity continuously decreased and water temperature increased particularly in shallow water regions. The impact of global climate change on the radiation conditions under water and its effects on primary production of seaweeds are discussed| since organisms in the eulittoral and upper sublittoral zones are affected by UV radiation throughout the polar day. In clearer water conditions during spring| this may also apply to organisms inhabiting greater depths. 5433,2001,4,3,Limitations of the equivalent CO2 approximation in climate change simulations,The "equivalent CO2" approximation often used to simulate the climatic effects of a suite of trace greenhouse gases is investigated using a recent version of the NCAR Community Climate Model. We performed present-day and preindustrial equilibrium climate simulations. The climate sensitivity is lower by similar to 20% in the equivalent CO2 case compared to the control case in which the individual trace gases were treated explicitly. This is reflected in similar percentage differences in global- and annual-mean surface temperature| precipitation| precipitable water| and sea ice. The temperature changes are also different regionally in the tropical and subtropical troposphere and in the stratosphere. This difference in climate sensitivity originates from differences in the spatial pattern of radiative forcing. The equivalent CO2 forcing pattern differs from the control case forcing pattern for several reasons| but the dependence on temperature of the Planck emission spectrum appears to be fundamentally most important. The primary absorption bands of CH4 and N2O are found at wavelengths more sensitive to the temperature-related shift of the wavelength of maximum emission than the absorption bands of CO2. This leads to stronger spatial variations in absorption by trace gases than by CO2. We conclude that because of differences in the pattern of radiative forcing| the equilibrium response of global climate to increases in trace gases is larger than the response to an "equivalent" increase in CO2| and the patterns of response are also different. 5389,2001,4,4,Long term persistence in the atmosphere: global laws and tests of climate models,The persistence of short term weather states is a well known phenomenon: A warm day is more likely to be followed by a warm day than by a cold one and vice versa. Using advanced methods from statistical physics that are able to distinguish between trends and persistence we have shown recently that this rule may well extend to months| years and decades| and on these scales the decay of the persistence seems to follow a universal power law. Here we review these studies and discuss| how the law can be used as an (uncomfortable) test bed for the state-of-the-art climate models. It turns out that the models considered display wide performance differences and actually fail to reproduce the universal power law behavior of the persistence. It seems that the models tend to underestimate persistence while overestimating trends| and this fact may imply that the models exaggerate the expected global warming of the atmosphere. (C) 2001 Elsevier Science BN. All rights reserved. 5619,2001,2,4,Long-term changes in plankton community structure and productivity in the North Pacific Subtropical Gyre: The domain shift hypothesis,Oceanic productivity| fishery yields and the net marine sequestration of atmospheric greenhouse gases are all controlled by the structure and function of planktonic communities. Detailed paleoceanographic studies have documented abrupt changes in these processes over timescales ranging from centuries to millennia. Most of these major shifts in oceanic productivity and biodiversity are attributable to changes in Earth's climate| manifested through large-scale ocean-atmosphere interactions. By comparison| contemporary biodiversity and plankton community dynamics are generally considered to be "static"| in part due to the lack of a suitable time frame of reference| and the absence of oceanic data to document ecosystem change over relatively short timescales (decades to centuries). Here we show that the average concentrations of chlorophyll a (chl a) and the estimated rates of primary production in the surface waters of the North Pacific Subtropical Gyre (NPSG) off Hawaii have more than doubled while the concentrations of dissolved silicate and phosphate have decreased during the past three decades. These changes are accompanied by an increase in the concentration of chl b| suggesting a shift in phytoplankton community structure. We hypothesize that these observed ecosystem trends and other related biogeochemical processes in the upper portion of the NPSG are manifestations of plankton community succession in response to climate variations. The hypothesized photosynthetic population "domain shift" toward an ecosystem dominated by prokaryotes has altered nutrient flux pathways and affected food web structure| new and export production processes| and fishery yields. Further stratification of the surface ocean resulting from global warming could lead to even more enhanced selection pressures and additional changes in biogeochemical dynamics. (C) 2001 Elsevier Science Ltd. All rights reserved. 5639,2001,2,4,Long-term trends in the seasonal cycle of Great Lakes water levels,Numerous long-term trends in the rate-of-change in monthly mean Great Lakes water levels are identified for the period 1860 to 1998. Statistically significant trends are found for 2| 4| 5| and 7 months of the year for Lakes Superior| Michigan-Huron| Erie| and Ontario| respectively. Many of the trends translate into large changes in net water flux (600 to 1|700 m(3)/s). In each case| significant positive trends are roughly offset by negative trends during other times of the year. Together with similar trends in monthly lake level anomalies (deviations from the annual mean)| these trends indicate important changes in the seasonal cycle of Great Lakes water levels. Specifically| Lakes Erie and Ontario are rising and falling (on an annual basis) roughly one month earlier than they did 139 years ago. Maximum lake levels for Lake Superior are also slightly earlier in the year| and the amplitude of the seasonal cycle of Lake Ontario is found to increase by 23% over the 139-year period. Some of the changes are consistent with the predicted impacts of global warming on spring snowmelt and runoff in the Great Lakes region. Other potential contributors to the observed trends include seasonal changes in precipitation and human induced effects such as lake regulation and changes in land use. 5528,2001,2,4,Loss of speciation rate will impoverish future diversity,Human activities have greatly reduced the amount of the earth's area available to wild species. As the area they have left declines| so will their rates of speciation. This loss of speciation will occur for two reasons: species with larger geographical ranges speciate faster: and loss of area drives up extinction rates| thus reducing the number of species available for speciation. Theory predicts steady states in species diversity| and fossils suggest that these have typified life for most of the past 500 million years. Modern and fossil evidence indicates that| at the scale of the whole earth and its major biogeographical provinces| those steady states respond linearly| or nearly so| to available area. Hence| a loss of x% of area will produce a loss of about x% of species. Local samples of habitats merely echo the diversity available in the whole province of which they are a part. So| conservation tactics that rely on remnant patches to preserve diversity cannot succeed for long. Instead| diversity will decay to a depauperate steady state in two phases. The first will involve deterministic extinctions| reflecting the loss of all areas in which a species can ordinarily sustain its demographics. The second will be stochastic| reflecting accidents brought on by global warming| new diseases| and commingling the species of the separate bio-provinces. A new kind of conservation effort| reconciliation ecology| can avoid this decay. Reconciliation ecology discovers how to modify and diversify anthropogenic habitats so that they harbor a wide variety of species. It develops management techniques that allow humans to share their geographical range with wild species. 5642,2001,2,4,Losses caused by weather and climate extremes: A national index for the United States,An annual index measuring past national losses and capable of measuring future loss from weather and climate extremes was developed to help measure future shifts in climate| a subject of great concern to the global warming issue and the insurance industry. Results from climate models indicate that a changed climate owing to global warming would alter and increase many extremes| and the objective of this study was to develop a national-scale index to monitor change in monetary losses and costs from weather and climate extremes. Forty-four historical variables addressing various aspects of weather and climate extremes and their effects on the U.S. economy since the late 1940s were assessed as potential input to such an index. Frequencies of most severe weather conditions from 1950 to 1997 did not correspond well with their financial impacts. However| hurricane losses did correspond with the frequency of intense hurricanes| and tornado losses corresponded well with the number of violent tornadic storms. Quality insurance loss data for several major storm types (thunder| hail| winter| and wind storms) were available| plus quality data on flood and hurricane losses| and all were adjusted to 1997 dollars. Techniques were developed to assess the effect of seasonal climate extremes on major crop yields and costs for electricity and natural gas consumed. Trends were upward for certain key variables between 1950 and 1997| including the incidence and losses associated with winter storms| flood losses| crop losses| and incidence of heavy rains. Trends were downward for other weather-driven loss variables including hurricane losses| energy costs| thunderstorm losses| wind storm losses| and hail losses. Nine loss variables were selected to develop the U.S. annual loss index| and in rank order| based on their average annual loss values| were energy costs| followed by losses from hurricanes| floods| severe convective storms| crops| tornadoes| winter storms| hail| and wind storms. The variables chosen also will be available in future years to allow a continuing assessment using the index. The 1950-1997 average annual index value was $17.47 billion (1997 dollars)| with annual values ranging from a high of $54.4 billion in 1972 to a low of $2.4 billion in 1963. The 48-year trend of the index was unchanging with three notable high loss periods: 1950-1954| 1970-1974| and 1990-1994. 5415,2001,2,4,Maps of lands vulnerable to sea level rise: modeled elevations along the US Atlantic and Gulf coasts,Understanding the broad-scale ramifications of accelerated sea level rise requires maps of the land that could be inundated or eroded. Producing such maps requires a combination of elevation information and models of shoreline erosion| wetland accretion| and other coastal processes. Assessments of coastal areas in the United States that combine all of these factors have focused on relatively small areas| usually 25 to 30 km wide. In many cases| the results are as sensitive to uncertainty regarding geological processes as to the rate of sea level rise. This paper presents maps illustrating the elevations of lands close to sea level. Although elevation contours do not necessarily coincide with future shorelines| the former is more transparent and less dependent on subjective modeling| Several methods are available for inferring elevations given limited data| This paper uses the US Geological Survey (USGS) 1degrees digital elevation series and National Oceanic and Atmospheric Administration (NOAA) shoreline data to illustrate the land below the 1.5 and 3.5 m contours for areas the size of entire US states or larger| The maps imply that approximately 58 000 km(2) of land along the Atlantic and Gulf coasts lie below the 1.5 m contour. Louisiana| Florida| Texas| and North Carolina account fur more than 80% of the low land| Outside of those 4 states| the largest vulnerable populated region is the land along the Eastern Shore of Chesapeake Bay stretching from Dorchester County| Maryland| to Accomac County| Virginia. 5671,2001,5,4,Mass extinction and bioevents across the Paleocene-Eocene boundary in the western Sinai| Egypt,This study discusses the general scenario of the P/E boundary events in the neritic to bathyal environment based mainly on the paleobathymetric distribution of the recorded taxa| as well as changes in paleoecology and paleoproductivity as observed in several sections of the Western Sinai. During the upper part of the Igorina pusilla pusilla Zone and the Globanomalina pseudomenardii Zone| a decrease in the P/B ratio is accompanied by well developed 'Midway-type' foraminiferal faunas with rare cosmopolitan bathyal species. They indicate a shallow marine environment and consequently a decrease in water productivity This decline in productivity was followed by a gradual increase due to a rise in the sea level during the Morozovella velascoensis Zone. Due to this rise of the sea level| representatives of the 'Midway-type' benthic fauna became scarce whereas the cosmopolitan bathyal forms became abundant. The oscillations in delta O-18 and delta C-13 values indicate a variations in the paleotemperature and an instability of the surface water productivity during the latest Paleocene. The increase in the temperature that matches well with the global warming in the latest Paleocene caused the extinction of many taxa. Only very few benthic foraminifera firstly occurred in the latest Paleocene and survived the P/E boundary event to become more abundant in the basal Eocene which is marked by a renewal of the benthic foraminiferal faunas by many incoming species. Rare Ostracodes are restricted to the Paleocene interval| but a few species appear in the uppermost Paleocene - lowermost Eocene. It seems that these South Tethyan ostracodes are less affected by the crisis at the P/E boundary.
5647,2001,2,4,Mass mortality event in red coral Corallium rubrum populations in the Provence region (France| NW Mediterranean),A mass mortality event of the red coral Corallium rubrum (L.) occur-red in the NW Mediterranean region in summer 1999. The main objectives of the present study were to document the mortality suffered by the red coral populations in the Provence region and assess ecological correlates of the mortality which could help to identify the putative agent or agents of the event. The mortality outbreak resulted in partial to complete loss of the coenenchyme. The first observations of red coral mortality in the study area were in early October 1999 and continued until November 1999| To determine the extent of mortality on red coral populations| the incidence (= % colonies suffering mortality) and the virulence [= % coenenchyme loss) were quantified. Twelve surveys were carried out from November 1999 to January 2000. A total of 874 colonies of the 2375 observed showed some mortality. Incidence and virulence differed significantly among surveys. In some cases about 80 % of the colonies were affected| while in others only 5 % of colonies showed some mortality. Depth had a strong influence on the incidence of mortality. Shallower populations had the greatest incidence| while populations deeper than 30 m depth showed no mortality. However| virulence was similar in the 10 to 30 m depth range. With regard to habitat| the entrances of caves displayed a significantly higher incidence but not virulence than the interiors. Given the life history traits of red coral (mainly slow growth and low recruitment)| it seems that recovery from the outbreak will be a long-term process. However| further studies are urgently required to provide basic information regarding red coral population dynamics as a basis for hypotheses on the actual recovery capability Of affected populations. The cause of the mass mortality is unknown. However| during late summer 1999| the NW Mediterranean area affected by the mass mortality event experienced high temperatures and hydrographic stability over a period of several weeks| This temperature anomaly could have caused physiological stress or/and triggered the development of pathogenic agents that otherwise would have remained non-virulent. This hypothesis is reinforced by the absence of signs of mass mortality below 30 m depth in red coral populations. Since the NW Mediterranean seems to be affected by the global warming trend| if the temperature hypothesis is confirmed| the long-term consequences of a repetition of this kind of event could severely endanger the persistence of shallow-water red coral populations. 5556,2001,2,4,Mathematical modelling of methane transport by Phragmites: the potential for diffusion within the roots and rhizosphere,The release of methane into the atmosphere by Phragmites australis (Cav.) Trin. ex Steud. can be considered as a two-stage process. The first| a mainly diffusive movement through the rhizosphere from the anaerobic source regions of the soil and into and along the roots to the root-rhizome junction. The second| the removal of the gas from the root-rhizome junction to the atmosphere through the rhizome-culm system| a process often dominated by convective (pressurised) gas how This article addresses the first of these stages and is presented in isolation because of its perceived commonality to wetland plants in general. The model treats the root and its oxygenated rhizosphere as a series of concentric cylinders: two non-(or low) porosity stelar cylinders| a highly porous cortex| a non-porous epidermal/hypodermal cylinder and the rhizosphere itself. The methane source lies at the edge of the oxygenated rhizosphere the dimensions of which are determined by the integrated effects of oxygen consumption in root and rhizosphere (the latter including a methanotrophic element) and the diffusive impedances throughout the system. The results demonstrate something of the complexity of root-methane-oxygen relations. Methane entry from the rhizosphere is shown to vary along the length of any individual root and| as expected| methane oxidation within the rhizosphere is found to reduce the potential for methane loss to the atmosphere. Situations are also revealed: (i) when the methane concentration falls to zero within the rhizosphere because of aerobic microbial consumption supported by radial oxygen loss from the root| and (ii) where methane may enter the root at one point and escape to the rhizosphere at some other. In this latter case| methane concentration minima are possible within the rhizosphere supplied by methane fluxes from both the root and the bulk soil. Predictions of the quantities of methane which might be released via Phragmites roots to the atmosphere accord with examples of those previously reported from field data. (C) 2001 Elsevier Science B.V. All rights reserved. 5630,2001,4,2,Measurements of methane emissions from landfills using a time correlation tracer method based on FTIR absorption spectroscopy,Methane is an important climate gas contributing significantly to global warming. A large part of the anthropogenic emissions of methane comes from landfills. Due to the biogenic origin of these emissions and the inhomogeneous characteristics of landfills and their soil cover| these emissions show large spatial variation. Thus| development of reliable and cost-effective methods for measurements of these emissions is an important task and a challenge to the scientific community. Traditionally| field chamber methods have been used but also different area integrating methods based on downwind plume measurements. These measurements have been supported by meteorological data either directly from local measurements or by controlled release of tracer gas from the landfill providing the dispersion characteristics of the plume. in this paper we describe a method| the Time Correlation Tracer method| combining controlled tracer gas release from the landfill with time-resolved concentration measurements downwind the landfill using FTIR absorption spectroscopy. The method has been tested and used on measurements at a landfill in southern Sweden over the past 1.5 years. The method has proven to be a usable method for measurements of total methane emission from landfills| and under favorable meteorological conditions we estimate an achievable accuracy of 15-30%. The real time analysis capability of the FTIR makes it possible to judge the success of the measurement already on site and to decide whether more measurements are necessary. The measurement strategy is relatively simple and straightforward| and one person can make a measurement from a medium sized landfill (1-4 ha) within a few days to a week depending on the meteorological situation. 5475,2001,3,4,Measurements of PVTx and saturation properties for the binary 1|1|1|2-tetrafluoroethane plus propane system,Natural refrigerants such as hydrocarbons (HCs) are considered as promising long-term alternatives in some of the restricted applications for refrigeration systems| since they have zero ozone depletion potential (ODP) values and negligible global warming potential (GWP) values. One of the crucial disadvantages of HCs| however| is flammability. For the purpose of solving this important issue| we have decided to study the thermodynamic properties of binary mixtures of HCs blended with. nonflammable HFC refrigerants. The present paper| therefore; aims to measure a set of reliable PVTx property data for the binary 1|1;1|2-tetrafluoroethane (R-134a) + propane (R-290) mixtures in two-phase and gas-phase regions. The experimental PVTx properties of the binary R-134a + R-290 system have been measured at four different compositions by a constant-volume method coupled with expansion procedures in an extensive range of temperatures from 312 K to 400 K| at pressures up to 6.1 MPa| and for densities up to 196 kg.m(-3)| respectively. The present study also aims to determine the dew-point pressures and the saturated-vapor densities of the present binary mixtures so as to develop a virial equation of state in the gaseous phase of the binary R-134a + R-290 system. 5564,2001,3,3,Measuring spatially resolved gas transport and adsorption in coal using MRI,The storage and transport of gases in coal is of tremendous importance in the utilisation of coalbeds| and in particular the recovery of methane. There is also increasing interest in the use of coal mines as sites for carbon dioxide sequestration to alleviate the potentially harmful effects of global warming. This paper demonstrates the use of magnetic resonance imaging to investigate the spatiotemporal dynamics of gas transport in coal. The presence of significant structural heterogeneities in the coal was observed. Dynamical effects displayed a broad range of time constants ranging from minutes to days. (C) 2001 Elsevier Science Inc. All rights reserved. 5493,2001,2,3,Mechanisms determining the Atlantic thermohaline circulation response to greenhouse gas forcing in a non-flux-adjusted coupled climate model,Models of the North Atlantic thermohaline circulation (THC) show a range of responses to the high-latitude warming and freshening characteristic of global warming scenarios. Most simulate a weakening of the THC| with some suggesting possible interruption of the circulation| but others exhibit little change. The mechanisms of the THC response to climate change using the HadCM3 coupled ocean-atmosphere general circulation model| which gives a good simulation of the present-day THC and does not require flux adjustment| were studied. In a range of climate change simulations| the strength of the THC in HadCM3 is proportional to the meridional gradient of steric height (equivalent to column-integrated density) between 30 degreesS and 60 degreesN. During an integration in which CO| increases at 2% per year for 70 yr| the THC weakens by about 20%| and it stabilizes at this level if the CO| is subsequently held constant. Changes in surface heat and water fluxes are the cause of the reduction in the steric height gradient that derives the THC weakening| 60% being due to temperature change (greater warming at high latitudes) and 40% to salinity change (decreasing at high latitude| increasing at low latitude). The level at which the THC stabilizes is determined by advective feedbacks. As the circulation slows down| less heat is advected northward| which counteracts the in situ warming. At the same time| northward salinity advection increases because of a strong increase in salinity in the subtropical Atlantic| due to a greater atmospheric export of freshwater from the Atlantic to the Pacific. This change in interbasin transport means that salinity effects stabilize the circulation| in contrast to a single basin model of the THC| where salinity effects are destabilizing. These results suggest that the response of the Atlantic THC to anthropogenic forcing may be partly determined by events occurring outside the Atlantic basin. 5549,2001,4,4,Mechanisms for pollutant transport between the boundary layer and the free troposphere,Pollutants are longer-lived in the free troposphere than the boundary layer| hence the transport of pollutants from the boundary layer to the free troposphere has significant implications for long-range transport and global warming. It is important to quantify the transport of air between the boundary layer and the free troposphere and to understand the role different meteorological mechanisms play| Idealised passive tracer experiments| with tracer initially only in the boundary layer| are performed in a numerical model for three case study days with different synoptic conditions. After 24 hours| more than 50% of the tracer resides in the free troposphere for the two frontal cases| and 40% resides there for the high-pressure case. The tracer was transported to maximum heights of 8 km| To elucidate the role of different mechanisms for each case| the tracer amount transported by advection only| advection and turbulent mixing| and advection and convection was calculated. Advection is found to be the most important mechanism in transporting the tracer to the free troposphere; however| the addition of upright convection and turbulent mixing increases the amount by up to 24% with convection transporting the tracer to heights of 5 km. The inclusion of convection and turbulent mixing to the advection are not linearly additive processes. This study shows the possibility of a large proportion of the pollutant emitted in the boundary layer being transported to the free troposphere in a short time and the importance of representing all the meteorological processes. 5442,2001,2,4,Meltwater and the global ocean conveyor: northern versus southern connections,The sensitivity of the ocean circulation to changes in North Atlantic surface fluxes has become a major factor in explaining climate variability. The role of the Antarctic Bottom Water in modulating this variability has received much less attention| limiting the development of a complete understanding of decadal to millennial time-scale climate change. New analyses indicate that the southern deepwater source may change dramatically (e.g.| experience a decrease of as much as two thirds during last 800 years). Such change can substantially alter the ocean circulation patterns of the last millennium. Additional analyses indicate that the Southern Hemisphere led the Northern Hemisphere changes in some of the glacial cycles of Pleistocene| implying a seesaw-type oscillation of the global ocean conveyor. The potential for melting of sea ice and ice sheets in the Antarctica associated with global warming can cause a further slowdown of the southern deepwater source. These results demand an assessment of the role of the Southern Ocean in driving changes of the global ocean circulation and climate. Systematic model simulation targeting the ocean circulation response to changes in surface salinity in the high latitudes of both Northern and Southern Hemispheres demonstrate that meltwater impacts in one hemisphere may lead to a strengthening of the thermohaline conveyor driven by the source in the opposite hemisphere. This| in turn| leads to significant changes in poleward heat transport. Further| meltwater events can lead to deep-sea warming and thermal expansion of abyssal water| that in turn cause a substantial sea-level change even without a major ice sheet melting. (C) 2001 Elsevier Science B.V. All rights reserved. 5665,2001,3,3,Methane emissions from wastewater management,Greenhouse gas emissions in the form of methane and carbon dioxide are produced when municipal and industrial wastewater and their residual solid by-product (sludge) are handled under or subject to anaerobic conditions| thus contributing to the global warming potential or the greenhouse effect. This paper presents estimation methods used for determining methane emissions from the management of wastewater. Applications for estimating countrywide methane gas emissions from wastewater management are presented with the country of Lebanon as an example. The relative significance of these emissions is assessed in comparison with methane emissions from developing and developed countries. Uncertainty associated with the estimation process and mitigation measures to reduce potential impacts of methane emissions from wastewater management are also discussed. (C) 2001 Elsevier Science Ltd. All rights reserved. 2987,2001,3,3,Methane hydrates potential as a future energy source,Gas hydrates are crystalline solids that form from mixtures of water and light natural gases such as methane| carbon dioxide| ethane| propane and butane. They are of considerable interest for their potential as an energy resource and for their potential role in global climate change. From an energy resource point of view| the enormous amounts of methane hydrate under the ocean and beneath arctic permafrost represent an estimated 53% of all fossil fuel (coal| oil| natural gas) reserves on earth| about 10|000 gigatons. The difficulty with recovering this source of energy is that the fuel is in solid form and is not amenable to conventional gas and oil recovery techniques. (C) 2001 Elsevier Science B.V. All rights reserved. 2974,2001,3,2,Mitigating climate change with renewable and high-efficiency generation,This paper focuses on the status of policy studies on Global Climate Change and how renewable and high-efficiency generation technology can be part of the solution. It considers critical technologies and solutions toward realizing the targets set in the Kyoto treaty. Discussed is energy efficiency in power generation| environmental benefits of high-efficiency gas turbines in competitive energy markets which display less NOx and CO2 emissions per unit of power produced while providing power generators with the most competitive electricity| and experience in India in mitigating climate change with renewable energy as seen by the UN and an advisor to the Indian government in nonconventional energy sources. Also discussed is stabilization of greenhouse gas concentrations in the atmosphere that will present dangerous anthropogenic interference with the climate system as called for under the United Nations Framework Convention on Climate Change. 5449,2001,3,4,Mitigation strategies using different methodologies to compare greenhouse gases,Mitigation strategies for greenhouse gases (GHG) developed by using the PERSEUS-NAT model for Germany are presented. The model covers all relevant GHG emitting sectors in a bottom-up approach| thus making it possible to elaborate consistent| notional reduction strategies. The model results show that in the case without emission restrictions the CO2 emissions will decrease until the year 2010 due to a fuel switch to natural gas. After the year 2010 the CO2 emissions will rise because of increasing natural gas prices which are assumed in manyforecasts. As a result of these gas prices| hard coal power plants using imported coal are the most economical option to satisfy base load electricity demand. If CO2 reduction targets are introduced| one of the Most important reduction option in the electricity sector is to substitute natural gas for hard coal. This gas will especially be used in modem combined cycle power plants. Large CO2 reduction potentials can also be opened up by a rigorous realisation of insulation measures and the installation of natural gas condensing boilers. Taking into account other greenhouse gases the results vary strongly in reliance on the method used to compare the different gases (Global Warming Potential method or Radiative Forcing method). 3046,2001,3,2,Modelling long-term C dynamics in croplands in the context of climate change: a case study from Ohio,A simple dynamic model (CBUDGET) was developed to quantify long-term carbon (C) dynamics in croplands. By using independent datasets (on continuous wheat) from the Waite Permanent Rotation Trial (Australia) and from Northwest Ohio| the tests of its performance resulted in R-2 values of 0.85 and 0.80| respectively| between observed and simulated values. Our model suggests that the rate of residual C addition into the soil is the primary factor that controls soil organic carbon (SOC) storage for Ohio croplands under continuous corn| wheat and oats for the period 1866-1996 and continuous soybean for the period of 1924-1996. The interaction of CO2-fertilization and a temperature increase of 0.5 degreesC decreased mean SOC levels for the selected crops over the same periods. A multiple linear regression model (MLR) relating carbon dioxide (CO2) emissions to population growth| affluence and energy intensity with an R-2 of 0.99 indicates the significance of underlying causes of anticipated climate change. The MLR model thus serves to capture a more complete picture of anthropogenic sources of global climate change than considering agricultural activities only in exploring locally and regionally mitigative and preventive measures towards global climatic stability. (C) 2001 Elsevier Science Ltd. All rights reserved. 3028,2001,4,4,Modelling respiration of vegetation: evidence for a general temperature-dependent Q(10),Temperature responses of rates of respiratory CO2 efflux from plants| soils| and ecosystems are frequently modelled using exponential functions with a constant Q(10) near 2.0 (fractional change in rate with a 10 degreesC increase in temperature). However| we present evidence that Q(10) declines with short-term increases in temperature in a predictable manner across diverse plant taxa. Thus| models using a constant Q(10) are biased| and use of a temperature-corrected Q(10) may improve the accuracy of modelled respiratory CO2 efflux in plants and ecosystems in response to temperature and predicted global climate changes. 5631,2001,2,3,Modelling the variability of the sea-ice conditions in the Baltic Sea under different climate conditions,The present and future ice conditions around 100 years from present in the Baltic Sea are examined h two 10 year integrations of an ice-ocean model. Results from atmospheric climate-model simulations constitute the atmospheric forcing| one representing present climate conditions (control simulation.)| and the other global warming due to CO2 doubling (scenario simulation). The present-day climatological ice conditions and the interannual variability were realistically reproduced by the ice-ocean model. The modelled range of the maximum annual ice extent in the Baltic was 190 420 x 10(3) km(2) the control simulation and 50 270 x 10(3) km(2) in the scenario simulation. The range of the annual maximum level-ice thickness was 45-85 and 20-58 cm in the control and scenario simulations| respectively. 5624,2001,2,4,Monitoring trace gas fluxes (N(2)O| CH(4)) from different soils under the same climatic conditions and the same agricultural management,In order to determine the effects of soil type on flux rates of N(2)O and CH(4) a 43-months field experiment with undisturbed soil monoliths (2 in height| 1 m(2) surface) was carried out. Four replicates of three sites in southern Germany were installed in a lysimeter station near Munich. All sites formerly were used as arable fields. The soil types varied in texture| gravel| pH and C and N content. The most important factor in this investigation was to expose the different soil types to the same climatic conditions and to the same agricultural management. Despite of the same conditions differences in both N(2)O and CH(4) flux rates were found. Annual N(2)O emissions ranged from 0.3 to 2 kg N(2)O-N ha(-1)a(-1) and CH(4) uptakes ranged from -1.13 to -0.59 kg CH(4)-C ha(-1)a(-1). N(2)O emissions from 'Hohenwart' were 7 times higher than the emissions measured from 'Kelheim'. Furthermore| the CH(4) uptakes from 'Kelheim' were 4.5 times higher than the 'Hohenwart' measurements. Calculating the global warming potential (GWP) as CO(2)-equivalents from N(2)O and CH(4) fluxes of the investigated soils the atmospherical load from 'Kelheim' was 75+/-91| from 'Scheyern' it was 468+/-119 and from 'Hohenwart' it was 611+/-192 kg CO(2) ha(-1)a(-1). 3007,2001,2,4,Morphophysiological and population adaptations of Ajuga reptans L. at the northern boundary of its range,The results of comprehensive morphophysiological and population studies on Ajuga reptans L.| a species of the nemoral floristic complex| at the northern boundary of its range (in the middle taiga subzone of the Komi Republic) are reviewed. Adaptations at the cell| organism| and biocenotic levels are revealed. The maintenance and survival of the species at the boundary of its range are provided for by its physiological plasticity| resistance to low temperatures| and multiple variants of ontogeny. Prognosis of Ajuga reptans future status under conditions of global climate change and expansion of anthropogenically disturbed areas is favorable. 3041,2001,5,4,Multiwave XRF-SR determination of U and Th in bottom sediments of Lake Baikal: Brunhes paleoclimatic chronology,The paper presents a new method of U and Th determination in bottom sediments implying synchrotron radiation with monochromatic beams at different energies| registration| and iterative Joint processing of the resultant XRF (X-ray fluorescent) spectra series| The validity of the new method was proved by comparison of U and Th determinations by XRF-SR in different sediment samples with earlier INAA and ICP-MS results for the same samples. Profiles of U and Th were measured at the sampling rate of 2 ka in a drilling core (BDP-96-2) of bottom sediments from Lake Baikal deposited 40 to 780 ka BP. Oscillations of U contents and U/Th ratios record global climate change throughout the Brunhes epoch (780 ka BP)| and the response of these "warm" proxies is similar to that observed earlier in shorter cores spanning the last two interglacials (220-0 ka BP). 5424,2001,3,3,N2O emissions from true meadows dependent on location and N fertilization,Agricultural production is thought to be a main anthropogenic emitter of nitrous oxide (N2O)| which contributes to global warming and the destruction of the ozone layer. There is still considerable uncertainty about the amount of N2O emission| and the site-specific parameters that affect N2O emission. From October 1995 until March 1998 experiments were conducted at established field plots (true meadows) at three different sites| i.e. low mountain range (Eifel)| lowland (Niederrhein)| and moist meadows (Munsterland). Plots were fertilized with calcium ammonium nitrate (CAN) at nitrogen equivalents ranging from 0 to 360 kg N ha(-1). N2O fluxes were measured throughout the whole year using the closed-chamber method. In addition| data on temperature| water-filled pore space and precipitation were collected. N2O emission rates (mg N2O-N ha(-1) h(-1)) were highest either after fertilizer application or in winter during frost| depending on the experimental site and N dosage. The annual amount of N losses clue to N2O emission was dependent on the experimental site and the type and dosage of fertilizer. Disregarding the 360 kg N ha (1) level of the CAN treatments| the N losses in this experiment were less than 1.5 kg N2O-N ha (1) yr (1). At low fertilizer dosage there was no reliable correlation between the amount of N that was applied and the amount of N2O that was emitted. However| with high fertilizer levels the N2O emissions increased gradually. Finally| N2O emissions were more influenced by the amount of CAN than by the site. 2971,2001,2,2,National Environment Health Association position global climate change,The impact of greenhouse gas emissions on both human beings and the global climate has been greatly debated in recent years (1). According to the United Nations Intergovernmental Panel on Climate Change (IPCC)| there has been a documented increase in global temperature measurements of 0.3[degrees] to 0.6[degrees]C over the last century (2). Further| a recent report from the National Research Council underscores the importance of anthropogenic (man-made) aerosols as agents of climate change (3| 4). Purpose. The National Environmental Health Association (NEHA) supports the precept that anthropogenic sources| specifically greenhouse gases| are responsible for a significant portion of the measured change in global climate. Further| NEHA supports the concept of an association between global warming and an increased risk to public health. Reducing the amount of greenhouse gases released into the atmosphere will benefit human health. This position paper reviews current information on the status of global climate change with particular emphasis on the implications for environmental and public health. It is intended to be used as a basis from which environmental and public health practitioners and colleagues in related fields can initiate discussions with policy makers at all levels--local| state| national| and worldwide.
5576,2001,2,4,Natural fire frequency for the eastern Canadian boreal forest: consequences for sustainable forestry,Given that fire is the most important disturbance of the boreal forest| climatically induced changes in fire frequency (i.e.| area burnt per year) can have important consequences on the resulting forest mosaic age-class distribution and composition. Using archives and dendroecological data we reconstructed the fire frequency in four large sectors along a transect from eastern Ontario to central Quebec. Results showed a dramatic decrease in fire frequency that began in the mid-19th century and has been accentuated during the 20th century. Although all areas showed a similar temporal decrease in area burned| we observed a gradual increase in fire frequency from the west to Abitibi east| followed by a slight decrease in central Quebec. The global warming that has been occurring since the end of the Little Ice Age (similar to 1850) may have created a climate less prone to large forest fires in the eastern boreal forest of North America. This interpretation is corroborated by predictions of a decrease in forest fires for that region of the boreal forest in the future. A longer fire cycle (i.e.| the time needed to burn an area equivalent to the study area) has important consequences for sustainable forest management of the boreal forest of eastern Canada. When considering the important proportion of overmature and old-growth stands in the landscape resulting from the elongation of the fire cycles| it becomes difficult to justify clear-cutting practices over all the entire area as well as short rotations as a means to emulate natural disturbances. Alternative practices involving the uses of variable proportion of clear| partial| and selective cutting are discussed. 5617,2001,2,4,Newly emerging and re-emerging infectious diseases,Infectious diseases are still dramatically affecting public health in global dimensions| in spite of the success of the 20th century medicine. Viruses represent the most serious threat for the future from the point of view of prevention as well as therapy| considering their ability to change rapidly their genetic information. Bacteria are also capable of mutation and acquisition of new genetic information from other bacteria| enabling them to generate new factors of virulence and to cause diseases with new clinical symptoms. Microorganisms acquire genes providing them with resistance to antimicrobial drugs and disinfectants| as well as with possibilities to create new antigens that affect both prevention and therapy| There is a reappearance of illnesses| such as diphtheria| which had been steadily receding in the second half of the last century. Changing lifestyle is another factor contributing to the increased spreading of infections. New diagnostic problems appear as the result of changing methods of food production and dietary habits in industrialised countries| accompanied with malnutrition in others| as well as of world-wide travel| contacts with new pathogens| life in overcrowded cities| industrial development| exploitation of natural resources| global warming and increasing number of immunocompromised people. Medical research discovered relations between well-known diseases (atherosclerosis| arthritis) and infectious agents. This resulted in changes in the approach to their prevention and treatment. Therefore| medicine in Slovakia needs to update knowledge of the occurrence of new and re-emerging infectious diseases both in Slovakia and abroad| and to organise their diagnostics in laboratories of clinical microbiology. 5633,2001,4,3,Nitrous oxide production and flux from soil under sod following application of different nitrogen fertilizers,Concern over contribution of nitrous oxide (N2O) to global warming and stratospheric ozone depletion has prompted measurement of nitrous oxide (N2O) emissions from agricultural soils and study of controlling factors. The objectives of this study were (1) to measure the magnitude of N2O emissions from application of (NH4)(2)SO4| Ca(NO3)(2) or urea teach at 100 kg N/ha) to a Kentucky bluegrass (Poa pratensis L.) stand| and (2) to compare flux of N2O from the surface measured with covers to N2O production and denitrification in soil cores collected at a depth of 2.5 -7.5 cm. Water| NH4+ and NO3 contents of soil cores were also measured. Application of all three fertilizers increased N2O production by soil cores| and N2O flux from covers. The two measurements differed in temporal pattern and magnitude. Flux of N2O from the soil surface is a more complex and variable process than N2O production in a specific soil layer. The possibility of increased N2O production with urea requires further investigation under more controlled conditions. Nitrification of NH4+ appeared to be the principal source of N2O. 2955,2001,2,4,Northern bobwhite (Colinus virginianus) abundance in relation to yearly weather and long-term climate patterns,We used a multilayered| backpropagation neural network to investigate the relative effects of yearly weather and long-term climate patterns on the abundance of northern bobwhites (Colinus virginianus: hereafter| bobwhite) in Oklahoma| USA. Bobwhite populations have been declining for several decades across the United States| and predicted global climate change might accelerate the rate of decline. We were interested in whether bobwhite abundance was more responsive to yearly precipitation and temperature| or to annual deviations from long-term mean climate patterns. We used roadside count data collected over a 6 year period (1991-1997) by the Oklahoma Department of Wildlife Conservation as a measure of bobwhite abundance. We standardized quail counts among counties by calculating the standard normal deviate for each county. Weather data were obtained from weather stations closest to the roadside-count route. We had 280 training cases and 68 test-validation cases. Two data sets were constructed: one using yearly weather data (actual rainfall and temperature) and the second using annual deviations from long-term mean values. We conducted simulation analyses to determine the nature of the relationship between each dependent variable and the standardized bobwhite counts. A neural network with eight neurons was most efficient for the yearly weather data| accounting for 25% of the variation in the training data. The adjusted sum-of-squares for this model was 2.42. A four-neuron network was selected for the deviation-from-normal data set| accounting for 23% of the variation in the training data. The adjusted sum-of-squares for the deviation model was 1.44| indicating it performed better than the model for yearly weather patterns. Deviation from long-term mean July and August temperatures combined contributed 31.5% to the climate network's predictions| and deviations from mean winter| spring| and summer precipitation combined contributed 42.8% to the network's predictions. As July temperature increased over the long-term mean| the number of bobwhites counted increased over the route mean| but the relationship decelerated at high July temperatures. Predicted increases in bobwhites counted were highest when August temperatures were below the mean and decreased rapidly for all temperatures greater than the mean. Predicted bobwhite counts increased asymptotically as winter rain increased over the long-term mean| but were greatest at mean spring-rainfall amounts and at below average amounts of summer rainfall. We conclude that the absolute changes in yearly weather pattern predicted by some global change models will not have as great an impact on bobwhite abundance as will the magnitude of the deviations of these values from the climate bobwhites are adapted to in this portion of their range. (C) 2001 Elsevier Science B.V. All rights reserved. 2980,2001,2,2,Numerical investigations of future ice conditions in the Baltic Sea,Global climate change is expected to have an effect on the physical and ecological characteristics of the Baltic Sea. Estimates of future climate on the regional scale can be obtained by using either statistical or dynamical downscaling methods of global AOGCM scenario results. In this paper| we use 2 different coupled ice-ocean models of the Baltic Sea to simulate present and future ice conditions around 100 years from present. Two 10-year time slice experiments have been performed using the results of atmospheric climate model simulations as forcing| one representing pre-industrial climate conditions (control simulation)| and the other global warming with a 150% increase in CO2 greenhouse gas concentration (scenario simulation). Present-day climatological ice conditions and interannual variability are realistically reproduced by the models. The simulated range of the maximum annual ice extent in the Baltic in both models together is 180 to 420.10(3) km(2) in the control simulation and 45 to 270.10(3) km(2) in the scenario simulation. The range of the maximum annual ice thickness is from 32 to 96 cm and from 11 to 60 cm in the control and scenario simulations| respectively. In contrast to earlier estimates| sea ice is still formed every winter in the Northern Bothnian Bay and in the most Eastern parts of the Gulf of Finland. Overall| the simulated changes of quantities such as ice extent and ice thickness| as well as their interannual variations are relatively similar in both models| which is remarkable| because the 2 coupled ice-ocean model systems have been. developed independently. This increases the reliability of future projections of ice conditions in the Baltic Sea. 5410,2001,3,4,Nutritional manipulation of methanogenesis in ruminants,The concentrations of greenhouse gases in the atmosphere are rising at a rapid rate which the human race has not experienced up to now. Methane is the important greenhouse gas after carbon dioxide is the gas now being paid most attention. Feeds ingested by herbivores include structural carbohydrates in the cell walls of plants. These polysaccharides are not digestible by digestive enzymes secreted from alimentary canal. However| many prokaryotic and enkaryotic bacteria synthesize enzyme complexes capable of degrading them efficiently| In consequence| huge amount of acetate and hydrogen are produced by the oxidation of pyruvate. It has been shown that hydrogen is a principal substrate for rumen methanogenesis by relating the rate of production of methane in rumen fluid. Thus| high digestibility of fibrous materials may result in high methane emission from enteric fermentation. Intensive research efforts have been directed towards the discovery of chemical agents which will modulate ruminal fermentation to improve feed efficiency. It is worth noting that overall the complex ecological system of the rumen works efficiently| particularly with aspect to cellulolysis. Therefore| our attempt to modify methane production should be selective and cause minimum disturbance to the rest of the rumen fermentation. In our efforts to seek natural manipulators which have a suppressing effect on rumen methanogenesis| prophylactic effects of sulphur containing amino acid| some plant extracts and probiotics on rumen methanogenesis have been studied in vitro and in vivo. 5446,2001,2,3,Observed and SST-forced seasonal rainfall variability across tropical America,Three experiments starting from different initial conditions have been made with the ECHAM-4 atmospheric General Circulation Model (GCM) integrated at T30 resolution forced with the observed sea-surface temperature (SST) over the period 1960-1994. The tropical America modes of seasonal rainfall anomalies whose time variation is most accurately simulated by the GCM have been searched for using Singular Value Decomposition Analyses (SVDA) and Canonical Correlation Analysis (CCA) between observed and model fields. The leading modes revealed by SVDA and CCA are highly similar| even though the ordering of the modes showed some fluctuation. A first skilful rainfall anomaly mode has weights of the same sign almost everywhere in tropical America. except along the western coast and the sub-tropical margins. This mode appears in all of the four seasons assessed. A second major skilful mode is usually a bipolar north-south (N-S) rainfall anomaly pattern (clear in December-March| DJFM: March-May| MAM| and June-September. JJAS). A large portion of the skill of the first rainfall anomaly mode (same sign anomalies across tropical America except small patches along the western coast) is through variance that is in common with the Southern Oscillation Index (SOI). In addition to forcing from the central/eastern tropical Pacific SST. there also appears a contribution from contrasting SST anomalies in the tropical Atlantic. This rainfall mode is usually a regional portion of a more large-scale mode encompassing at least the whole tropical zone (especially in DJFM| MAM and September-November. SON). Analysis of the relationship of this mode with GCM circulation features reveals that a rainfall deficit (respectively excedent) over the main rainbelt of the tropical America region is associated with strengthening (respectively weakening) of the sub-tropical westerly jet streams| a global warming (respectively cooling) of the tropical atmosphere. an anomalous divergence (respectively convergence) in the lower levels and an anomalous convergence (respectively divergence) in the upper levels over tropical America and in the region of the Atlantic Inter-tropical Convergence Zone (ITCZ). Such global features are not so apparent for the dominant mode of JJAS. even though the correlations with El Nino-Southern Oscillation (ENSO) indicators (as SOI or NINO3 SST index) are as high as for the other seasons. The bipolar N-S rainfall anomaly mode in tropical America is mostly related to anomalous N-S gradient of SST anomalies in the tropical Atlantic. The atmospheric circulation anomalies emphasize changes in 850 hPa meridional winds in the tropical Atlantic. However| there is also interannual variance of this rainfall mode in both the model and observations that is unexplained by tropical Atlantic SSTs| but which is explained by central/eastern tropical Pacific SSTs and| potentially| SSTs from other tropical and extratropical areas. This is especially true in MAM. Some differences in the details of the model and observed teleconnection patterns are noted. Such differences can be used to statistically adjust the model simulations using the CCA or SVDA modes as basis patterns. Both statistical approaches have been applied and the results are consistent between the two| The increase of skill is stronger when temporal correlation (the pattern correlation) between the model and observed pattern is high (low) as for JJAS. The skill is moderate to high around the whole Amazon basin. but remains relatively low inside the Amazon basin| though reliability of the observations themselves may influence this result. Averaged over all the seasons| about 15-35% (35-55%) of the interannual grid-box (regional) seasonal rainfall variance is skilfully simulated from the observed SST forcing. Copyright (C) 2001 Royal Meteorological Society. 5476,2001,4,4,Oceanographic research vessel Keifu Maru,The Japan Meteorological Agency (JMA) built a new oceanographic research vessel Keifu Maru in order to enhance the monitoring activities related to global environmental issues including climate change and global warming. Particular attention is focused on the role of the ocean in the climate change. The R/V Keifu Maru is specially equipped with the towed CTD system| which allows making measurements of upper ocean temperature and salinity underway| and the measuring system of carbon dioxide concentrations in the air and the sea surface water. 5626,2001,4,4,On the definition of a heat wave,Heat waves are a major cause of weather-related deaths. With the current concern for global warming it is reasonable to suppose that they may increase in frequency| severity| duration| or areal extent in the future. However| in the absence of an adequate definition of a heat wave| it is impossible to assess either changes in the past or possible consequences for the future. A set of definitions is proposed here| based on the criteria for heat stress forecasts developed by the National Weather Service (NWS). Watches or warnings are issued when thresholds of daytime high and nighttime low heat index (H-i) values are exceeded for at least two consecutive days. The heat index is a combination of ambient temperature and humidity that approximates the environmental aspect of the thermal regime of a human body| with the NWS thresholds representing a generalized estimate of the onset of physiological stress. These thresholds cannot be applied directly nationwide. In hot and humid regions| physical| social| and cultural adaptations will require that the thresholds be set higher to ensure that only those events perceived as stressful are identified. In other| cooler| areas the NWS criteria may never be reached even though unusually hot events may be perceived as heat waves. Thus| it is likely that a similar number of perceived heat events will occur in all regions| with the thresholds varying regionally. Hourly H-i for 178 stations in the coterminous United States was analyzed for the 1951-90 period to determine appropriate threshold criteria. Use of the NWS criteria alone indicated that much of the nation had less than three heat waves per decade| and this value was adopted as the baseline against which to establish suitable thresholds. For all areas| a percentile threshold approach was tested. Using all available data| daytime high and nighttime low thresholds were established separately for each specific percentile. Heat waves were treated as occurring when conditions exceeded both the daytime high and the nighttime low thresholds of the same percentile for two consecutive days. Several thresholds were tested. For much of the South| 1% thresholds produced appropriate values. Consequently| a heat wave was defined as a period of at least 48 h during which neither the overnight low nor the daytime high H-i falls below the NWS heat stress thresholds (80 degrees and 105 degreesF| respectively)| except at stations for which more than 1% of both the annual high and low H-i observations exceed these thresholds| in which case the 1% values are used as the heat wave thresholds. As an extension| "hot spells'' were similarly defined| but for events falling between the 1% values and NWS thresholds| with "warm spells'' occurring between the 2% and 1% values. Again| stations for which the 1% or 2% H-i values exceed the NWS thresholds were given modified definitions. The preliminary investigation of the timing and location of heat waves resulting from these definitions indicated that they correctly identified major epidemiological events. A tentative climatic comparison also suggests that heat waves are becoming less frequent in the southern and more frequent in the midwestern and eastern parts of the nation. 5467,2001,3,3,Oxidative conversion of PFC via plasma processing with dielectric barrier discharges,Perfluorocompounds (PFCs) have been extensively used as plasma etching and chemical vapor deposition (CVD) gases for semiconductor manufacturing processes. PFCs have significant effects on the global warming and have very long atmospheric lifetimes. Laboratory-scale experiments were performed to evaluate the effectiveness of CF4 conversion by using dielectric barrier discharges (DBD). The results of this study revealed that the removal efficiency of CF4 increased with application of higher voltage| gas residence lime| oxygen content| and frequency. Combined plasma catalysis (CPC) is an innovative way for abatement of PFC and experimental results indicated that combining plasma with catalysts could effectively remove CF4. Products were analyzed by Fourier transform-infrared spectroscopy (FT-IR) and the major products of the CF4 processing with DBD were CO2| COF2| and CO| when O was included in the discharge process. Preliminary results indicated that as high as 65.9% of CF4|vas decomposed with CPC operated at 15 kV| 240 Hz for the gas stream containing 300 ppmv CF4| 20% by volume O-2| and 40% by volume Ar| with N-2 as the carrier gas. 5555,2001,3,3,Oxynitridation of silicon with nitrogen plasma for flash memory applications characterized by high frequency capacitance-voltage measurements,Si(100) wafers were oxynitrided by nitrogen plasma exposure under different conditions and thermally oxidized in dry O-2 without the use of toxic or global warming gases. The atomic concentration ratio of N/Si was 0.075 at a plasma discharge power of 0.5 kW and an exposure time of 1 min and 0.176 at a plasma power of 2.0 kW and an exposure time of 3 min| as determined from X-ray photoelectron spectroscopy measurements. A progressive reduction in the oxidation rate with increasing N concentration| corresponding to an increase in N plasma power| was observed. The uniformity of film thickness over a 4-inch wafer was improved after nitrogen plasma exposure and rapid thermal oxidation| with a thickness variation of less than 2.6% compared with 13.2% for the N2O thermal oxidation process. The advantages of exposing Si to N plasma for application in silicon devices was investigated by high-frequency capacitance-voltage measurements. A distortion in the capacitance-voltage curve was observed for samples that did not undergo nitridation| a distortion that was not observed in the nitrided samples. Capacitance-voltage curve distortion was found to be significantly reduced by Si nitridation under low plasma power. (C) 2001 Elsevier Science B.V. All rights reserved. 5460,2001,3,4,P rho Tx measurements for gas-phase pentafluoroethane plus propane mixtures by the Burnett method,In some refrigeration-based applications| hydrocarbons (HCs) are expected to be promising long-term alternative refrigerants because of their zero ozone depletion potential (ODP) and negligible global warming potential (GWP) values. But there exists a serious disadvantage that they are flammable. Despite their flammability| however| commercial demands for HCs are increasing not only in several European countries but also in southeast Asia. On the other hand| the flammability is considered a major issue in U.S.A. and Japan. To suppress the flammability| blended mixtures of HCs with nonflammable HFCs are considered. As one of such mixtures| pentafluoroethane (R-125) and propane (R-290) mixtures are dealt with in the present study. Although the thermodynamic properties of each single component have been studied rather extensively| there is no study reported on those of this binary system. Accordingly| we have measured the gas-phase P rho Tx properties of the binary R-125 (1) + R-290 (2) system by using the Burnett isothermal -isochoric coupling method. The present measurements cover an extensive range of temperatures (305 to 380 K)| pressures up to 4.5 MPa| and densities up to 2.5 mol.dm(-3) for the binary systems with four different mole fractions of x(1) = 0.00| 0.29| 0.50| and 0.75| respectively. The present paper discusses the gas-phase P rho Tx properties for the first time regarding the present binary mixtures at their selected compositions. 5501,2001,5,3,Paleobiogeography of Pseudotextularia elegans during the latest Maastrichtian global warming event,A latest Maastrichtian global warming event| which began approximately 450 k.y. and ended about 22 k.y. prior to the K/T boundary| is associated with the poleward migration of the warm-water planktonic foraminifer Pseudotextularia elegans. The warming event was apparently inititated by greenhouse warming due to the main outpouring of the Deccan Traps in India and is now well documented in the North and South Atlantic Oceans and in North America by the poleward migration of warm-water planktonic foraminifera and subtropical vegetation. A cooling trend ca 22 kyr prior to the K/T boundary caused marine delta O-18 values to return to climatic conditions recorded prior to the onset of warming and thus does not represent a significant change in long-term climate. Planktonic foraminifera responded by migration to the latest Maastrichtian global warming and cooling before their mass extinction at the K/T. 5513,2001,5,4,Paleobotanical evidence for near present-day levels of atmospheric CO2 during part of the tertiary,Understanding the Link between the greenhouse gas carbon dioxide (CO2) and Earth's temperature underpins much of paleoclimatology and our predictions of future global warming. Here| we use the inverse relationship between Leaf stomatal indices and the partial pressure of CO2 in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO2 reconstruction based on fossil Ginkgo and Metaseguoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO2 remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO2 are required to explain these past intervals of global warmth. 3015,2001,5,4,Paleoecology of an exceptionally preserved arthropod fauna from lake deposits of the Miocene Barstow Formation| southern California| USA,A unique aquatic arthropod Konservat Lagerstatte occurs in Lacustrine-derived carbonate concretions within the Miocene Barstow Formation| of southern California. Faunal elements are primarily aquatic| salinity-tolerant| autochthonous predaceous diving beetle larvae| fly Larvae and pupae| mosquito and thrip larvae| and fairy shrimp. Three-dimensional preservation of soft tissues is via replacement by silica-based minerals as well as calcite| celestite| apatite| and gypsum. The fauna occurs in three beds (each 1-3 m thick) within an approximately 100 m sequence of predominantly microlaminated mudstone deposited in a saline-alkaline lacustrine environment. Faunal composition is consistent between sites and concretion beds| but faunal composition and diversity changed significantly during lake history| corresponding to differences in brine chemistry as well as preservational facies| resulting from the shift toward a more nearshore regime. The changes in lake chemistry and subsequent changes in fauna indicate lake shallowing as well as regional and global climate change towards greater aridity during the Miocene that also is coincident with regional uplift. 2985,2001,3,3,Particle transformations and export flux during an in situ iron-stimulated algal bloom in the Southern Ocean,During the first Southern Ocean Iron RElease Experiment (SOIREE)| a suite of biogeochemical measurements (water column (234)Th and delta (13)C(org) inventories| particle fluxes from sediment traps| phytoplankton sinking rates) were undertaken to test the hypothesis that the vertical export of particulate organic carbon (POC) is enhanced due to iron-induced increases in phytoplankton production. During the 13-days that the SOIREE bloom was monitored| export fluxes within the iron-fertilised patch were not substantially different to those in waters outside the bloom. On days 11-13| iron enrichment may have caused particle transformations that could lead to elevated future export via particle aggregation and/or diatom chain formation. The unknown time-lag between increased production and export| the longevity of the SOIREE bloom| and the absence of nutrient limitation over days 1-13| however| prohibit prediction of any iron-induced export. This conclusion highlights the difficulties of fully testing the "Iron Hypothesis" and for evaluating the implications for global climate change. 5591,2001,4,3,Performance of RegCM2.5/NCAR-CSM nested system for the simulation of climate change in East Asia caused by global warming,Regional climate in East Asia under 1CO(2) and 2CO(2) conditions| was simulated for continuous 10-year periods by the RegCM2.5 developed by NCAR| using the output of a CO2 transient run from NCAR-CSM as lateral and surface boundary conditions in order to evaluate the performance of the nested system for the use of climate change simulation caused by global warming for that region. In this study| January and June climates were analyzed. Through the validation of the simulated present climate| it was clarified that the typical precipitation phenomenon which occurs on the northwestern side of Japan during the winter monsoon is relatively well reproduced in the RegCM| but weakly in the CSM. It indicates that the RegCM. is essential for the prediction of regional climate change for the East Asia region. Although the present climate reproduced by the RegCM has some marked biases| e.g. the large cold bias in the higher latitude in winter and the missing of the Bai-u front in mainland China| they are mainly due to the overestimation of sea ice area| and the northward shift of the NPH (North Pacific High) in the CSM| respectively. The SST bias in the CSM significantly contributes to the surface air temperature bias on the coast. In the climate change simulations| the large-scale distributions of SLP and temperature in the RegCM bear a resemblance to those of the CSM in both months. On the other hand| the regional scale precipitation change patterns are different between the RegCM and the CSM in June| because the precipitation band near japan is well reproduced in the RegCM both in the 1CO(2) and the 2CO(2) climate. In this simulation| some notable climate change features are found| such as the temperature increase at higher latitudes in January| or intensification of the NPH extending to the southwest in June. Although these changes are statistically significant| they are mainly influenced by the bias in the CSM because the changes occur over the bias region| and their magnitudes do not necessarily exceed the bias of the simulated present climate. From these results| it should be stressed that it is of utmost importance that the AOGCM information is of good quality in the prediction of regional climate change. 5461,2001,2,4,Phenology is a major determinant of tree species range,Global warming is expected to have a major impact on plant distributions| an issue of key importance in biological conservation. However| very few models are able to predict species distribution accurately| although we know species respond individually to climate change. Here we show| using a process-based model (PHENOFIT)| that tree species distributions can be predicted precisely if the biological processes of survival and reproductive success only are incorporated as a function of phenology. These predictions showed great predictive power when tested against present distributions of two North American species - quaking aspen and sugar maple - indicating that on a broad scale| the fundamental niche of trees coincides with their realized niche. Phenology is shown here to be a major determinant of plant species range and should therefore be used to assess the consequences of global warming on plant distributions| and the spread of alien plant species. 5506,2001,2,4,Photoperiodic response to early hatching in a migratory bird species,A considerable number of bird species of the northern hemisphere have been breeding earlier over the last few decades| most probably in response to global warming. In migratory birds| there is also a trend towards later departure from the breeding grounds in autumn. Yet it is not known whether this trend in the timing of migration reflects an evolutionary process or is just an immediate phenotypic response to global environmental change. We conducted an experiment with migratory blackcaps (Sylvia atricapilla) to investigate how the photoperiodic conditions experienced by birds hatching earlier in the season affect the timing of post-juvenile moult and the onset of autumn migration. In a split-brood experiment| we reared 30 nestlings from six different families and kept them either under a photoperiodic regime simulating conditions 6 weeks before their actual hatching date or under simulated natural photoperiods. Time-shifted birds started moulting at an earlier age compared to controls and showed an early phase of nocturnal migratory activity. Under the influence of long day lengths moult was prolonged and migratory activity was interrupted. However| the termination of moult and the reinitiation of migratory activity were not delayed to the extent that birds compensated for the simulated early hatching date. Thus| we suggest that extant physiological responses to the photoperiod are maladaptive under the novel environmental conditions imposed by a global increase in temperature| leading to earlier autumn migration in juvenile birds with earlier breeding. 5641,2001,3,4,Photosynthetic performance of a cyanobacterium in a vertical flat-plate photobioreactor for outdoor microalgal production and fixation of CO2,A vertical flat-plate photobioreactor was developed for the outdoor culture of microalgae using sunlight as the light source. The ability for biomass production and CO2 fixation was evaluated by using a cyanobacterium| Synechocystis aquatilis SI-2. The average areal productivity was 31 g biomass m(-2) d(-1)| which corresponded to a CO2 fixation rate of 51 g CO2 m(-2) d(-1)| sustainable in the northern region of Japan during the winter time (January and February). The relationships between the efficiency of solar energy utilization of the reactor and its effect factors (cell concentration and irradiation) were investigated. 2994,2001,4,4,Phylogeography in coastal marine animals: a solution from California?,Aim Recently discovered deep phylogenetic gaps in coastal California marine taxa are geographically discordant with the provincial biogeographic boundary at Point Conception. This discordance runs contrary to the phylogeographic hypotheses that were derived from studies of coastal marine taxa in south-eastern North America. Here| I investigate the nature of the discrepant phylogeographic and biogeographic patterns in coastal California. Location Coastal south-western North America. Methods The scientific literature describing the phylogeography and biogeography of coastal California taxa was reviewed. Data describing life-history characteristics| habitat| and degree of phylogeographic structure were extracted and compared. The geographical distribution of phylogenetic breaks was compared with regional biogeographic data. Results All taxa were genetically variable. Those with greater dispersal ability generally had less phylogeographic structure. Although few taxa had very limited dispersal ability| many exhibited phylogeographic breaks within the California Transition Zone| a region of gradual species replacement between Oregonian and Californian biogeographic provinces. The most precisely resolved phylogeographic breaks were geographically concordant with peaks in the distribution of edge-effect species| which are strong indicators of environmental discontinuities| or ecotones. Moreover| these phylogeographic gaps| edge-effect species| and ecotones coincide geographically with Late Pleistocene faunal discontinuities and probable long-term physical barriers to gene flow. Main conclusions Contrary to prior inference| phylogeographic patterns in coastal California marine taxa are consistent with the phylogeographic hypotheses. The concordance of phylogeographic. and biogeographic patterns in the coastal marine faunas of south-eastern and south-western North America| and also the Indo-Pacific| suggests that the phylogeographic hypotheses are generally applicable to many coastal marine settings. As such| they provide a framework for investigating and comparing patterns of evolution in disparate coastal marine faunas. 5481,2001,2,4,Physiologic plasticity| evolution| and impacts of a changing climate on Pinus contorta,Climate response functions for 125 Pinus contorta populations were updated to assess the impact of 16 climate change scenarios on forest productivity. Productivity was defined as the volume of wood expected per hectare at age 20 and was calculated as the product of predicted individual tree volumes| an initial stocking (1600 trees ha(-1))| and predicted survival. Impact was considered according to the transient effects of a changing climate governed by (1) physiological plasticity in the contemporary generation and (2) long-term evolutionary adjustments that provide adaptedness and optimize productivity in future generations. Direct short-term plastic responses were geographically complex and had repercussions throughout the species' distribution even when temperature fluctuations were small (+/- 1 degrees C) and changes in distribution were inconsequential. Evolutionary adjustments ameliorated negative short-term impacts while enhancing the positive. Scenarios that encompassed predictions for global warming produced short-term impacts that were negative in the south and positive in the north| but subsequent evolutionary adjustments projected substantial increases in productivity. The long-term adjustments may require only 1 to 3 generations in the north but 6 to 12 generations in the south| thereby taking between 200 and 1200 years. 2958,2001,2,4,Phytophenological trends in Switzerland,Nation-wide phenological observations have been made in Switzerland since 1951. In addition to these observation programmes| there are two very long phenological series in Switzerland: leaf bud burst of horse-chestnut trees has been observed in Geneva since 1808 and full flowering of cherry trees in Liestal since 1894. In addition to the presentation of these two long phenological series| trends for 896 phenological time series have been calculated with national data from 1951 to 1998. The earlier bud burst of horse-chestnut trees in Geneva can be attributed mainly to the city effect (warmth island). This phenomenon was not observed with the cherry tree flowering in Liestal. A clear trend towards earlier appearance dates in spring and a weak tendency towards later appearance dates in autumn could be shown with data from the national observation network. It must be noted that different phenophases and plant species react differently to various environmental influences. 5469,2001,3,3,Plasma reforming and coupling of methane with carbon dioxide,Plasma reforming and coupling of methane with carbon dioxide using a point-to-point typo of reactor have been invested. A feed mixture of CH(4) and CO(2) could be converted mainly to CO| H(2)| and C(2)H(2) at atmospheric pressure and without external heating except plasma heating. Under a condition of 200 mL/min of CH(4) and CO(2) (CH(4):CO(2) volume ratio| 50:50)| a 2.5 min discharge gap| and a pulse frequency of 10.3 kPPS| CH(4) and CO(2) conversion| CO and C(2)H(2) selectivities| H(2)/CO ratio| and (CH(4) + CO(2)) conversion efficiency were 65.9% and 57.8%| 85.9% and 11.3%| 0.99| and 2.4 mmol/kJ| respectively. C(2)H(2) selectivity and H(2)/CO ratio could be moderated by changing CH(4) concentration in the feed mixture. The influence| of methane concentration and pulse frequency on product selectivity and plasma energy efficiency was evaluated. A brief economic evaluation of this process was given. The coproduction of acetylene of high value remarkably improved the production of synthesis gas (CO + H(2)) from carbon dioxide reforming of methane| which could also contribute the emission reduction of global warming gas CO(2). 5488,2001,3,2,Polylactides: Properties and prospects of an environmentally benign plastic from renewable resources,Pressing environmental and economic concerns dictate the need to develop new synthetic macromolecules based on renewable resources. The vast majority of existing materials are based on non-renewable fossil resources that will eventually be extinguished. Manufacturing synthetic polymers and disposal by incineration produces CO2 and contributes to global warming. For these reasons| poly(lactic acid) (PLA) polymers are of increasing commercial interest because they are derived from a renewable resources| sequester significant quantities of carbon dioxide relative to petrochemical based materials| conserve energy| and easily degrade. The mechanical properties of PLA are compared to other commodity plastics and it is shown that PLA closely resembles polystyrene. The effects of blending linear and branched chain architectures are discussed and it is shown that this provides a convenient method for controlling the elasticity and viscosity of the composite material without affecting mechanical or permeation properties. The melt rheology of high L content linear PLAs shows two unique features; they may be drawn to large Hencky strains without breaking and they exhibit considerable strain hardening. As a result| PLA is easily processed into fiber form. Due to the excellent combination of mechanical| rheological| and environmental properties| the prospects for widespread commercialization of PLA are excellent. 5439,2001,3,3,Pore structure of sheared coals and related coalbed methane,Coalbed methane is considered to be one of the major contributors to global warming. Geological prospecting of the rich-storage zone of methane is an important precondition for gas recovery projects. Shear zones along coal seams have long been considered as a major place where gas outbursts occur during mining| but they also have a positive aspect in coalbed methane prospecting and production because of their great quantity of fractures and high methane content. Mercury penetrating experiments on a series of variously sheared coal samples from the Pingdingshan coalfield| China| were performed. The results showed that tectonically sheared coals possess three to eight times more porosity and two to ten times more specific surface area than their normal counterparts. Moreover| brittlely deformed coals possess larger average fracture apertures representing a good condition for methane extraction whereas ductilely deformed coals show a fracture aperture even smaller than normal coals| which can explain why intensely sheared coals become difficult for methane extraction. The occurrence of a large number of tectonic fractures in a shear zone will make it easier for an artificial fracture to increase the permeability of coals in methane production. Therefore| except for locally ductile deformation areas| shear zones along coal seams are the best source and reservoir for methane gas production and| if this methane is extracted| it will help not only the reservoir but also protect the earth against global warming. 5406,2001,2,4,Positive feedbacks among forest fragmentation| drought| and climate change in the Amazon,The Amazon basin is experiencing rapid forest loss and fragmentation| Fragmented forests are more prone than intact forests to periodic damage from El Nino-Southern Oscillation (ENSO) droughts| which cause elevated tree mortality| increased litterfall| shifts in plant phenology| and other ecological changes| especially near forest edges| Moreover| positive feedbacks among forest loss| fragmentation| fire| and regional climate change appear increasingly likely Deforestation reduces plant evapotranspiration| which in turn constrains regional rainfall| increasing the vulnerability of forests to fire. Forest fragments are especially vulnerable because they have dry| fire-prone edges| are logged frequently| and often are adjoined by cattle pastures| which are burned regularly. The net result is that there may be a critical "deforestation threshold" above which Amazonian rainforests can no longer be sustained| particularly in relatively seasonal areas of the basin. Global warming could exacerbate this problem if it promotes drier climates or stronger ENSO droughts. Synergisms among many simultaneous environmental changes are posing unprecedented threats to Amazonian forests. 5583,2001,2,3,Potential impact of climate change on marine export production,Future climate change will affect marine productivity| as well as other many components of Earth system. We have investigated the response of marine productivity to global warming with two different ocean biogeochemical schemes and two different atmosphere-ocean coupled general circulation models (GCM). Both coupled GCMs were used without flux correction to simulate climate response to increased greenhouse gases (+1% CO2/yr for 80 years). At 2xCO(2)| increased stratification leads to both reduced nutrient supply and increased light efficiency. Both effects drive a reduction in marine export production (-6%) although regionally changes can be both negative and positive (from -15% zonal average in the tropics to +10% in the Southern Ocean). Both coupled models and both biogeochemical schemes simulate a poleward shift of marine production due mainly to a longer growing season at high latitudes. At low latitudes the effect of reduced upwelling prevails. The resulting reduction in marine productivity| and other marine resources| could become detectable in the near future| if appropriate long-term observing systems are implemented. 2973,2001,2,4,Precipitation and temperature effects on populations of Aedes albopictus (Diptera : Culicidae): Implications for range expansion,We investigated how temperature and precipitation regime encountered over the life cycle of Aedes albopictus (Skuse) affects populations. Caged populations of A. albopictus were maintained at 22| 26| and 30 degreesC. Cages were equipped with containers that served as sites for oviposition and larval development. All cages were assigned to one of three simulated precipitation regimes: (1) low fluctuation regime - water within the containers was allowed to evaporate to 90% of its maximum before being refilled| (2) high fluctuation regime - water was allowed to evaporate to 25% of its maximum before being refilled| and (3) drying regime - water was allowed to evaporate to complete container dryness before being refilled. Greater temperature and the absence of drying resulted in greater production of adults. Greater temperature in combination with drying were detrimental to adult production. These precipitation effects on adult production were absent at 22 C. Greater temperatures and drying treatments yielded higher and lower eclosion rates| respectively and| both yielded greater mortality. Development time and size of adults decreased with increased temperatures| and drying produced larger adults. Greater temperatures resulted in greater egg mortality. These results suggest that populations occurring in warmer regions are likely to produce more adults as long as containers do not dry completely. Populations in cooler regions are likely to produce fewer adults with the variability of precipitation contributing less to variation in adult production. Predicted climate change in North America is likely to extend the northern distribution of A. albopictus and to limit further its establishment in arid regions. 3031,2001,2,4,Predicting climate change effects on Appalachian trout: Combining GIS and individual-based modeling,We coupled an individual-based model of brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss) with a geographic information system (GIS) database to predict climate change effects on southern Appalachian stream populations. The model tracked individuals of both species through the daily processes of spawning| growth| feeding| mortality| and movement for 30 years in a stream reach consisting of connected pools| runs| and riffles. The southern Appalachian Plateau was divided into 101 watershed elevation band zones. Model simulations were performed for a representative stream reach of each stream order in each zone. Trout abundance was estimated by multiplying predicted trout densities (measured in number of trout per meter) by the total length of streams of each order in each watershed elevation zone. Three climate change scenarios were analyzed: temperature only (1.5-2.5 degreesC warmer stream temperatures); temperature and how (warmer stream temperatures and lower baseline flows with threefold higher peak hows); and temperature| flow| and mortality episodes (warmer stream temperatures| changed hows| and flow-related scouring of redds). Increased temperature alone resulted in increased abundances of brook and rainbow trout. The temperature-and-how scenario resulted in a complex mosaic of positive and negative changes in abundances in zones| but little change in total abundance. Addition of episodic mortality in the form of floods that scour redds and kill eggs and fry caused a net loss of rainbow trout. Predicted changes in habitat (based on simulation results and temperature alone) were| at best| weakly correlated with predicted changes in abundance. The coupling of individual-based models to GIS databases| in order to scale up environmental effects on individuals to regional population responses| offers a promising approach for regional assessments. 5480,2001,4,2,Predicting patterns of near-surface air temperature using empirical data,The signal of recent global warming has been detected in meteorological records| borehole temperatures and by several indirect climate indicators. Anthropogenic warming continues to evolve| and various methods are used to study and predict the changes of the global and regional climate. Results derived from GCMs| palaeoclimate reconstructions| and regional climate models differ in detail. An empirical model could be used to predict the spatial pattern of the near-surface air temperature and to narrow the range of regional uncertainties. The idea behind this approach is to study the correlations between regional and global temperature using century-scale meteorological records| and to evaluate the regional pattern of the future climate using regression analysis and the global-mean air temperature as a predictor. This empirical model| however| is only applicable to those parts of the world where regional near-surface air temperature reacts linearly to changes of the global thermal regime. This method and data from a set of approximately 2000 weather stations with continuous century-scale records of the monthly air temperature was applied to develop the empirical map of the regional climate sensitivity. Data analysis indicated that an empirical model could be applied to several large regions of the World| where correlations between local and global air temperature are statistically significant. These regions are the western United States| southern Canada| Alaska| Siberia| south-eastern Asia| southern Africa and Australia| where the correlation coefficient is typically above 0.9. The map of regional climate sensitivity has been constructed using calculated coefficients of linear regression between the global-mean and regional annual air temperature. As long as the correlations between the local and global air temperature are close to those in the last several decades| this map provides an effective tool to scale down the projection of the global air temperature to regional level. According to the results of this study| maximum warming at the beginning of the 21st century will take place in the continental parts of North America and Eurasia. The empirical regional climate sensitivity defined here as the response of the mean-annual regional temperature to 1 degreesC global warming was found to be 5-6 degreesC in southern Alaska| central Canada| and over the continental Siberia| 3-4 degreesC on the North Slope of Alaska and western coast of the U.S.A.| and 1-2 degreesC in most of the central and eastern U.S.A. and eastern Canada. Regions with negative sensitivity are located in the southeastern U.S.A.| north-western Europe and Scandinavia. The local tendency towards cooling| although statistically confirmed by modern data| could| however| change in the near future. 5462,2001,2,4,Predicting the potential future distribution of four tree species in ohio using current habitat availability and climatic forcing,We investigated the effect of habitat loss on the ability of trees to shift in distribution across a landscape dominated by agriculture. The potential distribution shifts of four tree species (Diospyros virginiana| Oxydendron arboreum| Pinus virginiana| Quercus falcata var. falcata) whose northern distribution limits fall in the southern third of Ohio were used to assess possible distribution shift scenarios as a result of global warming. Our predictions derive from the results of simulations using (a) forest inventory based estimates of current distribution and abundance of target species; (b) a satellite-based estimate of forest habitat availability; and (c) a tree migration model (SHIFT). The current distribution and abundance of trees was estimated using USDA Forest Service's Forest Inventory Analysis data and distribution maps from the late 1960s; pre-European settlement forest-nonforest maps were used to represent the fully forested condition for calibration and comparison. Habitat-availability estimates in Ohio were estimated using classified Landsat Thematic Mapper (TM) data from 1994. Tree abundance| forest availability and migration were modeled using a 1-km(2) pixel size. Forest availability was estimated as the proportion of forested TM pixels within each cell. The probability of a migrating species colonizing an unoccupied cell is modeled as a function of forest availability and distance to occupied cells. The results of the migration models suggest that the species studied are capable of colonizing virtually any forested location within Ohio over the next 100 years if climatic controls over the current distribution that may currently inhibit northward movement are relaxed. The contiguous distribution of these species| however| is not likely to shift more than 10 km during the next century regardless of the magnitude of the climate change. Examining the sensitivity of our simulations by varying critical model attributes| we found that whereas the variables controlling the amount of long-distance dispersal have strong effects on migration rates in the fully forested 1800 situation| they have significantly lesser effects on projections of future migration into highly fragmented forests. The low forest availability that characterizes much of the current Ohio landscape| along with the low likelihood of long distance dispersal| result in potential distribution shifts that are concentrated within the principally forested corridors in southeastern Ohio. We propose that in contrast to the past| future tree migrations are likely to be spatially and temporally correlated as a result of large climatic forcing and channelization through limited regions of available habitat. With respect to the management of biodiversity| this result suggests that it may be very difficult to discern plant migrations of native forest species owing to exceedingly slow rates of movement. 5558,2001,3,4,Process and environmental benefits with solvent-free stripping,Photoresist removal following dry etching or high-dose ion implantation conventionally employs solvents and acids| sometimes preceded by a dry oxygen-based plasma ash| These costly| hazardous| and polluting wet chemicals are then disposed of through environmentally unfriendly waste-disposal processes| often contributing to global warming| substantial energy consumption| ground water contamination| etc. A new cleaning process (ENVIRO) that dry ashes etched resist and simultaneously renders remaining material 100% DI water soluble has been qualified in manufacturing and successfully used for more than 12 months. Normalized for a 10|000 wafer-starts/week fab| this process can save more than $5 million/year in solvent costs alone. 5543,2001,2,3,Productivity of Trifolium subterraneum and Phalaris aquatica under warmer| high CO2 conditions,Despite the importance of grass-legume pastoral ecosystems worldwide| there is little known about the impacts of concurrent increase in temperature and atmospheric CO2 concentration on their productivity. Pure and mixed swards of subterranean clover (Trifolium subterraneum) and phalaris (Phalaris aquatica) were established under ambient and warmed (+3.4 degreesC) air temperatures| at ambient and 690 mu mol mol(-1) CO2 concentrations in field tunnels in temperate south-eastern Australia. Over one year| elevated CO2 increased clover foliage growth in the monoculture by 19%| and by 31% in the mixture. Warming reduced clover monoculture herbage production at ambient CO2 by 28% and reduced the growth enhancement by elevated CO2 to +8%. Forage growth of phalaris monoculture was not affected significantly by either factor. Forage growth of the mixture was increased by 34% in response to higher CO2| but unaffected by warming. Elevated CO2 combined with warming increased forage growth of the mixed sward by 23%. Concurrent rise in atmospheric CO2 concentration and temperature increased productivity of subterranean clover-phalaris swards. However| longer term effects on species competition and persistence may modify this conclusion. 2961,2001,2,4,Public health risk assessment linked to climatic and ecological change,Disturbances of climatic and ecological systems can present risks to human health| which are becoming more evident from health studies linked to climate variability| landuse change and global climate change. Waterborne disease agents| such as Giardia cysts and Cryposporidium oocysts have been positively correlated with rainfall. El Nino-related extreme weather conditions can have a significant impact on vector- and water-borne diseases. The linkages between weather| terrestrial ecology and human health have been discovered for some diseases| such as rodent-borne hantavirus. Marine ecology also plays a role in determining human health risks| such as from cholera| and other enteric pathogens. Deforestation and ensuing changes in landuse| human settlement| commercial development| road construction| and water control systems singly| and in combination have been accompanied by increases in or emergence of diseases like malaria and schistosomiasis in some regions of the world. Long-term climate change may increase the frequency of heat waves and potentially air pollution episodes| increase the number of extreme weather events| cause coastal flooding and salination of fresh water aquifers| and displace coastal settlements. Ultimately| a two-pronged approach (empirical and modeling studies) is required to better understand these linkages between climatological and ecological change as determinants of disease. 5569,2001,4,4,Reconstruction of the surface warming history of western interior Canada from borehole temperature profiles and other climate information,Over the past several decades annual surface air temperature (SAT) warming in western interior Canada has been more than twice that of the global average. Inversions of the temperature profiles in boreholes throughout this large region provide evidence of anomalously high ground surface temperature (GST) warming trends between the mid-19th century and present. Previous studies have identified strong SAT/GST associations throughout this region for the 20th century. This analysis of the composite| century-scale| regional GST histories (GSTHs) is based on the deepest available borehole temperature logs from the Foreland Sedimentary Basin in western and northern Canada| east of the Cordillera. Although separated by almost 20 degrees latitude| there is strong regional correlation (r = 0.98) between the GSTHs developed from northern (boreal forest) and southern (prairie grassland) boreholes. When filtered| the GSTHs of western Canada correlate strongly with the northern hemisphere (r = 0.80) and the Canadian Arctic (r = 0.86) high temporal resolution proxy climate histories. Strong correlation also exists between the prairie grassland GSTH curve and the tree-ring-based surface summer temperature history from the Columbia Icefield in the Canadian Rocky Mountains close to Athabasca Glacier (r = 0.95). These findings strongly suggest that the similar| but enhanced| SAT warming signal identified by GSTHs makes western interior Canada a strong indicator region of global warming. 5400,2001,2,4,Recruitment of pelagic fish in an unstable climate: Studies in Sweden's four largest lakes,Pelagic fish population biology was studied in the large Swedish lakes Vanern| Vattern| Malaren and Hjalmaren. It is crucial for fish fry in temperate regions to hatch early in the growth season to survive| and achieve large size before winter| and it is suggested that the key factors are to match the spring development of phyto- and zooplankton| but to avoid predation. This is more easily accomplished by the studied spring spawners smelt (Osmerus eperlanus) and pike-perch (Stizostedion lucioperca) than autumn spawners| such as vendace (Coregonus albula). It is shown that hatching of vendace fry shortly after ice-break-up is beneficial for year-class strength. In oligotrophic large lakes with few predatory species a rapid increase in water temperature after ice-break is also promoting recruitment| whereas this is not the case in eutrophic lakes where predation pressure from other species may become too high. The results indicate that autumn spawners will have difficulties in adapting to global warming and it is also suggested that the life history can explain the large variations observed in year-class strength between years. 2981,2001,2,3,Regional air pollution and climate change in Europe: An integrated assessment (AIR-CLIM),The aim of the AIR-CLIM project is to perform an integrated analysis of the linkages between climate change and regional air pollution in Europe and to produce results that are relevant to European policy-making. Key elements of the analysis are on the impact side the exceedances of critical thresholds for air pollution and global change and on the cost side the estimates of costs to reduce emissions of greenhouse gases and air pollutants. The integrated modeling framework set up to meet these objectives consists of two state-of-the-art integrated models covering regional air pollution in Europe (RAINS) and global climate change (IMAGE)| supplemented by new components. Based on a preliminary analysis it can be stated that climate change will make European vegetation in most regions less sensitive to acid deposition. Taking into account the emission trends the impacts of regional air pollution will decrease while the impacts of climate change increase. Different problems will be important in different regions: regional air pollution in Central and northern Europe| and climate change in southern Europe. 5527,2001,2,2,Regional-scale assembly rules and biodiversity of coral reefs,Tropical reef fishes and corals exhibit highly predictable patterns of taxonomic composition across the Indian and Pacific Oceans. Despite steep Longitudinal and Latitudinal gradients in total species richness| the composition of these key taxa is constrained within a remarkably narrow range of values. Regional-scale variation in reef biodiversity is best explained by Large-scale patterns in the availability of shallow-water habitat. Once habitat area is accounted for| there is surprisingly little residual effect of Latitude or Longitude. Low-diversity regions are most vulnerable to human impacts such as global warming| underscoring the urgent need for integrated management at multinational scales. 5650,2001,3,3,Renewable energy: Power for a sustainable future,By the end of the 21st century| according to United Nations projections| the number of people on the earth is likely to have approximately doubled. How can a world of 10 to 12 billion people be provided with adequate supplies of energy| cleanly| safely and substantially? There is a growing consensus that renewable energy sources will be a very important part of the answer. The growing interest in "renewables" has been prompted in part| by increasing concern over the pollution| resource depletion and possible climate change implications of our continuing use of conventional fossil and nuclear fuels. But recent technological developments have also improved the cost-effectiveness of many of the renewables. making their economic prospects look increasingly attractive. it describes the achievement and progress made in hydropower| biomass conversion| geothermal| solar thermal technology| wind energy conversion and the increasing usage of photovoltaics. It is evident that global warming is setting in and is going to change the climate as well as the terrain of many countries unless drastic measures are taken. The Kyoto meeting emphasized the importance of limiting CO| emissions and to abide by some form of agreement to reduce emissions. Present study concludes that renewable energy penetration into the energy market is much faster than was expected in recent years and by 2030| 15-20 percent of our prime energy will be met by renewable energy. 5643,2001,3,3,Renewable methane from anaerobic digestion of biomass,Production of methane via anaerobic digestion of energy crops and organic wastes would benefit society by providing a clean fuel from renewable feedstocks. This would replace fossil fuel-derived energy and reduce environmental impacts including global warming and acid rain. Although biomass energy is more costly than fossil fuel-derived energy| trends to limit carbon dioxide and other emissions through emission regulations| carbon taxes| and subsidies of biomass energy would make it cost competitive. Methane derived from anaerobic digestion is competitive in efficiencies and costs to other biomass energy forms including heat| synthesis gases| and ethanol. (C) 2000 Elsevier Science Ltd. All rights reserved. 3038,2001,2,3,Respiration of recently-fixed plant carbon dominates mid-winter ecosystem CO2 production in sub-arctic heath tundra,Arctic ecosystems could provide a substantial positive feedback to global climate change if warming stimulates below-ground CO2 release by enhancing decomposition of bulk soil organic matter reserves. Ecosystem respiration during winter is important in this context because CO2 release from snow-covered tundra soils is a substantial component of annual net carbon (C) balance| and because global climate models predict that the most rapid rises in regional air temperature will occur in the Arctic during winter. In this manipulative field study| the relative contributions of plant and bulk soil organic matter C pools to ecosystem CO2 production in mid-winter were investigated. We measured CO2 efflux rates in Swedish sub-arctic heath tundra from control plots and from plots that had been clipped in the previous growing season to disrupt plant activity. Respiration derived from recently-fixed plant C (i.e.| plant respiration| and respiration associated with rhizosphere exudates and decomposition of fresh litter) was the principal source of CO2 efflux| while respiration associated with decomposition of bulk soil organic matter was low| and appeared relatively insensitive to temperature. These results suggest that warmer mid-winter temperatures in the Arctic may have a much greater impact on the cycling of recently-fixed| plant-associated C pools than on the depletion of tundra bulk soil C reserves| and consequently that there is a low potential for significant initial feedbacks from arctic ecosystems to climate change during mid-winter. 5541,2001,2,4,Response of alpine chironomid communities (Lake Chuna| Kola Peninsula| northwestern Russia) to atmospheric contamination,A short sediment core from the deepest part of an alpine lake (Lake Chuna| Kola Peninsula| northwestern Russia)| covering about the past 200 yrs of sediment accumulation| was analysed for chironomid head capsule remains. The lake has been receiving acidic precipitation and heavy metals loading from the atmosphere since the 1940's. A total of 22 chironomid taxa were recorded. The most important taxa were typical elements of oligotrophic lakes| i.e. Micropsectra insignilobus| Paratanytarsus penicillatus| Stictochironomus spp. and Heterotrissocladius marcidus. Based on the cluster analyses results for the reconstructed environmental variables and chironomid communities| three developmental stages were distinguished from the lake history: (1) Natural ontogeny stage (before 1945); (2) Initial stage of anthropogenic ontogeny (1945-1982); and (3) Anthropogenic ontogeny stage (1982-1996). During the first period| the changes in the chironomid fauna were characterized as an anthropogenically undisturbed community| with M. insignilobus dominating (46-66%). The changes during the second period reflected the initial phase of anthropogenic succession associated with the beginning of acidification and heavy metal pollution. The main species showed opposite distributional patterns in this period; the abundance of the group M. insignilobus/Stictochironomus spp. decreased| whereas the abundance of P. penicillatus/H. marcidus increased. The third period was characterized by a major shift in the faunal assemblages| from M. insignilobus to other dominant species including P. penicillatus (19-30%). The increases of Orthocladiinae relative abundance and total organic content in the uppermost sediment layers may be explained by a decrease in lake productivity. The decreases of cold-stenothermal taxa Stictochironomus spp. and M. insignilobus in the uppermost sediment layers can be explained by the global warming during the 20th century. The lake ecosystem is likely to be affected by both inputs of airborne contaminants and climate changes. 5499,2001,2,4,Response of seedlings of three dominant shrubs to climate warming in Ordos plateau,Ordas plateau is a classical semi-dry sandland in China. The dry ecosystem responds sensitively to water-heat pattern of global change there. The distribution pattern and productivity of terrestrial ecosystem are greatly affected by global warming. Ecological adaptation strategies of seedlings of Caragana intermedia Kuang et H. C. Fu| Hedysarum mongolicum Turcz. and Artemisia ordosica Kraschen.| three dominant shrubs in Ordas plateau| were investigated in terms of morphological plasticities| biomass effects and photosynthetic and physiological characters| to the global warming by artificially controlling two temperature levels. The results show that the effects of temperature enhancement on growth and photosynthetic and physiological characters were obviously different among these three plant species. Temperature enhancement significantly increased tree height| leaf number| leaf area| biomass| photosynthetic rate| transpiration rate and stomatal conductance of C. intermedia and H. mongolicum seedlings| indicating that elevated temperature significantly affected the growth of these seedlings positively. Elevated temperature had almost no significant effect on the growth of A. ordosica seedlings. Their leaf number| leaf size| leaf area| biomass| transpiration rate and stomatal conductance did not increase obviously| but tree height and photosynthetic rate obviously increased with increasing temperature. Interspecific growth was significantly different among C. intermedia| H. mongolicum and A. ordosica seedlings. Except leaf size| values of the other seven characters of C. intermedia seedlings were greater than those of H. mongolicum and A. ordosica seedlings. 3040,2001,2,4,Salinization: unplumbed salt in a parched landscape,The global hydrological and salt cycles are described| as are the ways in which human activities have led to their disturbance. One effect of this disturbance is the unnatural increase in the salinity of many inland waters (secondary salinization). The geographical extent of secondary salinization is outlined| together with its effects on various types of inland waters| such as salt lakes| freshwater lakes and wetlands| and rivers and streams. The likely impact on salinization of global climate change is summarized. 2984,2001,2,4,Savanna-forest hysteresis in the tropics,A simple dynamic model relating forest area in a region| its contribution to dry season precipitation and the effect on its own establishment was developed. The model equation shows hysteresis between forest and savannas as a function of imported dry season precipitation. Regions are either dominated by forests or savannas| with each ecosystem showing stability despite changes in imported dry season precipitation. Deforestation beyond a certain threshold value| however| could cause a collapse of forest ecosystems and replacement by savannas in marginal areas. The predictions of this model corroborate pollen core analysis in the Amazon basin| where historical stability of tropical forest cover has been shown despite global climate change. 2969,2001,3,4,Science and precaution in the appraisal of electricity supply options,The technological risks associated with electricity generating options are a crucial consideration in the governance of energy strategies. Conversely| many central issues in the broader social debate over the governance of environmental risk (such as acid gas emissions| radioactive waste management| nuclear safety and global climate change) relate very strongly to technology choice in the electricity supply sector. The particularities of this field| therefore| offer a topical and pertinent case with which to explore the relationship between science and precaution in the governance of technological risk. By reference to the electricity sector| the present paper examines the contrasts between 'risk-based' and 'precautionary' approaches to the governance of risk| paying particular attention to the problems of intractable uncertainties and divergent values. A number of theoretical and methodological issues in conventional risk-assessment and cost-benefit analysis are examined and their practical implications for appraisal explored. Attention then turns to the form that might be taken by approaches to the governance of energy risks that are at the same time scientifically well-founded and precautionary. Conclusions are drawn for decision and policy making in this area. (C) 2001 Elsevier Science B.V. All rights reserved. 3006,2001,2,4,Seasonal patterns of photosynthesis in Douglas fir seedlings during the third and fourth year of exposure to elevated CO2 and temperature,The interactive effects of elevated atmospheric CO2 and temperature on seasonal patterns of photosynthesis in Douglas fir (Psuedotsuga menziesii (Mirb.) France) seedlings were examined. Seedlings were grown in sunlit chambers controlled to track either ambient (similar to 400 p.p.m.) CO2 or ambient +200 p.p.m. CO2| and either ambient temperature or ambient +4 degreesC. Light-saturated net photosynthetic rates were measured approximately monthly over a 21 month period. Elevated CO2 increased net photosynthetic rates by an average of 21% across temperature treatments during both the 1996 hydrologic year| the third year of exposure| and the 1997 hydrologic year. Elevated mean annual temperature increased net photosynthetic rates by an average of 33% across CO2 treatments during both years. Seasonal temperature changes also affected net photosynthetic rates. Across treatments| net photosynthetic rates were highest in the spring and autumn| and lowest in July| August and December-January. Seasonal increases in temperature were not correlated with increases in the relative photosynthetic response to elevated CO2. Seasonal shifts in the photosynthetic temperature optimum reduced temperature effects on the relative response to elevated CO2. These results suggest that the effects of elevated CO2 on net photosynthetic rates in Douglas fir are largely independent of temperature. 5485,2001,2,4,Seasonal variation in territory occupancy of non-breeding Long-billed Curlews in intertidal habitats,During the non-breeding season| many shorebirds use coastal habitats where tides influence their dispersion patterns and social systems. We spot-mapped Long-billed Curlews (Numenius americanus) at the Elk River estuary| California to examine variation in territory occupancy troth May 1999-April 2000. Curlew abundance was highest (a maximum of It; territorial and tip to 10 non-territorial birds) from July to September| after which time numbers declined progressively to 2-6 in winter. Five curlews were resident on >50% of observation days (N = 133) trout June-April: these individuals returned to the estuary earlier and departed later than 11 other territorial curlews that were present 12-37% of occasions and mostly from July-November. Territory occupancy declined in association with precipitation and diurnal low tides ranging between -0.7 and 1.3 m. The absence of two territorial curlews coincided with rainy periods. The absence of curlews front five territories coincided with neap (low) tides; lour of these curlews held territories at lower intertidal elevations with gently sloping topographies| such that they were inundated longer than other territories. At the Elk River estuary. territoriality may limit the number of curlews using intertidal habitats| but individual variation in territory residency suggests that numbers| and possibly carrying capacity| changed seasonally with availability of food in intertidal and pasture habitats. Habitat losses| such as those accompanying moderate (25-50 cm) rises in sea level associated with global warming| may reduce the carrying capacity of estuaries where existing levees preclude creation of new intertidal habitat. 5593,2001,4,3,Short-term volume changes of the Greenland ice sheet in response to doubled CO2 conditions,This paper focuses on the role of accumulation and cloudiness changes in the response of the Greenland ice sheet to global warming. Changes in accumulation or cloudiness were often neglected| or coupled to temperature changes. We used model output on temperature| precipitation and cloudiness from a GCM (ECHAM4 T106). The GCM output was used to drive the Greenland model that exists of a vertically averaged ice now model| coupled to a 1D surface energy balance model that calculates the ablation. Variables are temperature| accumulation and cloudiness. Sensitivity experiments with this model show that changes in accumulation are very important for the ice sheet mass balance| whereas cloudiness is of secondary importance. If the Greenland model is forced by the GCM output| the Greenland model is found to contribute 70% less to sea level rise after 70 years than is indicated by the results presented in the IPCC report. This large discrepancy is mainly due to the fact that the enhanced ablation is strongly compensated by increased accumulation. Comparing the result obtained here with changes in mass balance derived directly from the same general circulation model| indicates a 20% larger contribution to sea level. This increase is due to changes in ice now| and a different method for the ablation calculation. 5640,2001,2,4,Significance of water complexes in the atmosphere,Using standard statistical and thermodynamic procedures| we calculate equilibrium constants for the formation of select| hydrogen-bonded water complexes| namely the water dimer and the cyclic trimer and tetramer| and use them to estimate the atmospheric abundances of these species. We generate water complex altitude profiles (0-30 km) for both a saturated and an unsaturated atmosphere and discuss the dominant factors influencing our results. In our analysis| particular emphasis is given to the significance that water monomer concentrations| complex binding energies| hydrogen-bond energies| and entropy have on the calculated abundance profiles. We examine the importance of enthalpy and entropy at atmospheric temperatures and show how each contributes to our calculated equilibrium constants. By applying a universal 2 degreesC temperature increase throughout the troposphere and lower stratosphere| we are able to model the effect that global warming would have on (H2O)(n) abundances in a saturated atmosphere. We also illustrate the effect that this thermal variation would have on entropy| enthalpy| and K-p(T) values. Based on our results| we assess the atmospheric significance of water dimers and cyclic water complexes. (C) 2001 Elsevier Science Ltd. All rights reserved. 5660,2001,2,4,Simulated changes in atmospheric transport climate,Atmospheric "transport climate'' characterizes how trace gases are distributed by and within the atmosphere| on average| as a consequence of the interaction of atmospheric flow with tracer sources and sinks. The change in transport climate under global warming is investigated using passive tracers. Experiments with constant localized surfaces sources| pulsed sources| and pulsed boundary conditions are analyzed using a Green-function approach in conjunction with a climatological budget calculation. Under climate warming| interhemispheric exchange times| mixing times| and mean transit times all increase by about 10%. The main transport pathway between the hemispheres via the "tracer fountain'' at the ITCZ is suppressed. Generally less vigorous flow manifests itself in higher tracer burdens in the source hemisphere and in downwind plumes of enhanced mixing ratio close to the sources; these increases are also about 10%. Resolved advection and subgrid transport do not cooperate for all sources in enhancing the near-source mixing ratio. The warmer climate has a reduced cross-tropopause gradient| primarily due to a slightly higher tropopause| which results in a reduction of about 25% in the average tropospheric tracer mixing ratio| and a corresponding enhancement in the stratosphere. A global variance budget shows increased mean and transient tracer variance due to increased generation from strengthened mean gradients near the source and weakened eddy and subgrid transport. 5656,2001,4,3,Simulated changes in the frequency of extremes and regional features of seasonal/annual temperature and precipitation when atmospheric CO2 is doubled,Following a transient increase in the atmospheric carbon dioxide to double the current level| and a subsequent maintenance at the doubled level| there is a climate shift toward a new equilibrium state. Changes in the mean temperature and precipitation| and changes in the occurrence frequencies of their extremes for the doubled carbon dioxide conditions have been assessed at the continental scale. There is a characteristic spatial pattern that involves a maximum annual mean warming in high northern latitudes and a minimum annual mean warming around Antarctica and in the northern North Atlantic. Under maintained doubled carbon dioxide| this interhemispheric asymmetry disappears except for an ocean-land asymmetry. A possible mechanism for this is considered in terms of changes in effective thermal capacity due to a reduction of overturning in the oceans that continues to decline after the atmospheric carbon dioxide stops increasing. It is also found that global warming becomes most noticeable in the occurrence frequency of high extremes in the annual mean temperature in the low latitudes| even though the temperature rise is largest in the high northern latitudes in autumn and winter. In addition| extremes of large (small) annual and seasonal total precipitation are recorded much more frequently in regions where the mean precipitation increases (decreases). 5652,2001,4,3,Simulation of climate change induced by CO2 increasing for East Asia with IAP/LASG GOALS model,Two simulations| one for the control run and another for the perturbation run| with a global coupled ocean-atmosphere-land system model (IAP/LASG GOALS version 4) have been carried out to study the global warming| with much detailed emphasis on East Asia. Results indicate that there is no climate drift in the control run and at the time of CO| doubling the global temperature increases about 1.65 degreesC. The GOALS model is able to simulate the observed spatial distribution and annual cycles of temperature and precipitation for East Asia quite well. But| in general| the model underestimates temperature and overestimates rainfall amount for regional annual average. For the climate change in East Asia| the temperature and precipitation in East Asia increase 2.1 degreesC and 5% respectively| and the maximum warming occurs at middle-latitude continent and the maximum precipitation increase occurs around 25 degreesN with reduced precipitation in the tropical western Pacific. 5625,2001,3,4,Simultaneous measurement of NH3| N2O and CH4 to assess efficiency of trace gas emission abatement after slurry application,The application of liquid organic fertilizers can directly or indirectly induce the emission of trace gases. There are already a number of investigations on mitigation strategies| but most of them focus on one gas only and neglect the fact| that conditions reducing the emission of one trace gas might have a directly opposed effect on another. We conducted several field experiments to investigate the influence of application technique and pre-treatment of slurry on trace gas emissions after slurry application. Ammonia| CH4 and N2O where measured simultaneously. It could be clearly shown| that some of the tested slurry management techniques had contrary effects on the emissions of the different trace gases. With information on emissions of single trace gases| wrong conclusions might be drawn concerning the effectiveness of mitigation options. By comparing the emissions based on CO2 equivalents| the different management options can be compared comprising all three studied trace gases. 5418,2001,2,4,Snow depth manipulation and its influence on soil frost and water dynamics in a northern hardwood forest,Climate change will likely result in warmer winter temperatures leading to less snowfall in temperate forests. These changes may lead to increases in soil freezing because of lack of an insulating snow cover and changes in soil water dynamics during the important snowmelt period. In this study| we manipulated snow depth by removing snow for two winters| simulating the late development of the snowpack as may occur with global warming| to explore the relationships between snow depth| soil freezing| soil moisture| and infiltration. We established four sites| each with two paired plots| at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire| U.S.A. and instrumented all eight plots with soil and snow thermistors| frost tubes| soil moisture probes| and soil lysimeters. For two winters| we removed snow from the designated treatment plots until February. Snow in the reference plots was undisturbed. The treatment winters (1997/1998 and 1998/1999) were relatively mild| with temperatures above the seasonal norm and snow depths below average. Results show the treated plots accumulated significantly less snow and had more extensive soil frost than reference plots. Snow depth was a strong regulator of soil temperature and frost depth at all sites. Soil moisture measured by time domain reflectometry probes and leaching volumes collected in lysimeters were lower in the treatment plots in March and April compared to the rest of the year. The ratio of leachate volumes collected in the treatment plots to that in the reference plots decreased as the snow ablation seasons progressed. Our data show that even mild winters with low snowfall| simulated by snow removal| will result in increased soil freezing in the forests at the HBEF. Our results suggest that a climate shift toward less snowfall or a shorter duration of snow on the ground will produce increases in soil freezing in northern hardwood forests. Increases in soil freezing will have implications for changes in soil biogeochemical processes. 5610,2001,4,4,Snow interception evaporation. Review of measurement techniques| processes| and models,A global warming| primarily affecting wintertime conditions at high latitudes will influence the functioning of the boreal forest. The least known term of the winter water-balance equation is evaporation of snow intercepted in forest canopies. Several investigations stress the importance of snow-interception evaporation in coniferous forests and evaporation fractions of gross precipitation as large as 0.2-0.5 have been observed by investigators in Scotland| Canada| and Japan. Evaporation rates as high as 0.56 mm h(-1) are reported. The largest differences between the rain and snow interception evaporation processes are the differences in Storage. Snow storage (both mass and duration) is often an order of magnitude larger than that for rain. Snow interception changes the canopy albedo although some studies indicate the opposite. Process knowledge is limited because of measurement difficulties but it is known that canopy closure| aerodynamic resistance (r(a))| and vapour-pressure deficit are important factors. Existing formulations of r(a) as function of storage location and age cannot fully explain observed differences in evaporation rates. Operational hydrology and weather models| and GCMs describe snow interception in a very simplified way and might benefit from incorporation of more realistic schemes. 5479,2001,2,4,Soil degradation| global warming and climate impacts,A water balance model is used to assess the relative impacts of global warming and soil degradation scenarios on water resources in the future. Results indicate that overall global warming will have a more widespread and greater impact on climate change. However soil degradation could also play a significant role in water resource issues in the future. Based on the model results| wet and dry climate regions are particularly susceptible to impacts from soil degradation. In general| reduced water holding capacities will result in increased water runoff during wet periods| which will result in higher overland flow rates and reduced recharge rates to groundwater. Water lost to runoff will also increase deficits during dry periods| in effect increasing the duration and intensity of dry periods. 5540,2001,3,3,Solid waste treatment as a high-priority and low-cost alternative for greenhouse gas mitigation,The increased concern about environmental problems caused by inadequate waste management| as well as the concern about global warming| promotes actions toward a sustainable management of the organic fraction of the waste. Landfills. the most common means to dispose of municipal solid waste (MSW)| lead to the conversion of the organic waste to biogas| containing about 50% methane| a very active greenhouse gas (GHG). One unit of methane has a global warming potential of 21 computed for a 100-year horizon or 56 computed for 20 years. The waste sector in Israel contributes 13% of total greenhouse gases (GHG) emissions for a time horizon of 100 years (for a time horizon of 20 years| the waste sector contribution equals to more than 25% of total GHG emissions). The ultimate goal is to minimize the amount of methane (CH4) by converting it to CO2. This can be achieved by physicochemical means (e.g.| landfill gas flare| incineration) or by biological processes (e.g.| composting. anaerobic digestion). Since the waste in Israel has a high organic material content| it was found that the most cost-effective means to treat the degradable organic components is by aerobic composting (investment of less than US$ 10 to reduce emission of one ton CO2 equivalent per year). Another benefit of this technology is the ability to implement it within a short period. The suggested approach| which should be implemented especially in developing countries| could reduce a significant amount of GHG at relatively low cost and short time. The development of a national policy for proper waste treatment can be a significant means to abate GHG emissions in the short term| enabling a gain in time to develop other means for the long run. In addition| the use of CO2 quotas will credit the waste sector and will promote profitable proper waste management. 5571,2001,4,6,Sources of global warming in upper ocean temperature during El Nino,Global average sea surface temperature (SST) from 40 degreesS to 60 degreesN fluctuates +/-0.3 degreesC on interannual period scales| with global warming (cooling) during El Nino (La Nina). About 90% of the global warming during El Nino occurs in the tropical global ocean from 20 degreesS to 20 degreesN| half because of large SST anomalies in the tropical Pacific associated with El Nino and the other half because of warm SST anomalies occurring over similar to 80% of the tropical global ocean. From examination of National Centers for Environmental Prediction [Kalnay et al.| 1996] and Comprehensive Ocean-Atmosphere Data Set [Woodruff et al.| 1993] reanalyses| tropical global warming during El Nino is associated with higher troposphere moisture content and cloud cover| with reduced trade wind intensity occurring during the onset phase of EI Nino. During this onset phase the tropical global average diabatic heat storage tendency in the layer above the main pycnocline is 1-3 Wm(-2) above normal. Its principal source is a reduction in the poleward Ekman heat flux out of the tropical ocean of 2-5 Wm(-2). Subsequently| peak tropical global warming during El Nino is dissipated by an increase in the flux of latent heat to the troposphere of 2-5 W m(-2)| with reduced shortwave and longwave radiative fluxes in response to increased cloud cover tending to cancel each other. In the extratropical global ocean the reduction in poleward Ekman heat flux out of the tropics during the onset of El Nino tends to be balanced by reduction in the flux of latent heat to the troposphere. Thus global warming and cooling during Earth's internal mode of interannual climate variability arise from fluctuations in the global hydrological balance| not the global radiation balance. Since it occurs in the absence of extraterrestrial and anthropogenic forcing| global warming on decadal| interdecadal| and centennial period scales may also occur in association with Earth's internal modes of climate variability on those scales. 5657,2001,4,3,Southern Hemisphere atmospheric circulation response to global warming,The response of the Southern Hemisphere (SH)| extratropical| atmospheric general circulation to transient| anthropogenic| greenhouse warming is investigated in a coupled climate model. The extratropical circulation response consists of a SH summer half-year poleward shift of the westerly jet and a year-round positive wind anomaly in the stratosphere and the tropical upper troposphere. Along with the poleward shift of the jet| there is a poleward shift of several related fields| including the belt of eddy momentum-flux convergence and the mean meridional overturning in the atmosphere and in the ocean. The tropospheric wind response projects strongly onto the model's "Southern Annular Mode'' (also known as the "Antarctic oscillation'')| which is the leading pattern of variability of the extratropical zonal winds. 5470,2001,2,4,Spatial and seasonal variations of Q(10) determined by soil respiration measurements at a Sierra Nevadan forest,We examined the spatial and seasonal variation of Q(I0) as an indicator of the temperature sensitivity of soil respiration based on field measurements at a young ponderosa pine plantation in the Sierra Nevada Mountains in California. We measured soil CO2 efflux and soil temperature and moisture in two 20 in x 20 m plots from June 1998 to August 1999. The Q(10) values calculated from soil temperature at 10-cm. depth ranged spatially from 1.21 to 2.63 among 18 chamber locations in the plots. Seasonally| the Q(10) values calculated on the basis of the average Soil CO2 efflux and temperature (10 cm) across the sites could vary from 1.05 to 2.3. Q(10) and soil temperature are negatively correlated through a simple linear relationship with R-2 values of 0.45| 0.40| and 0.54 for soil temperature at 5-| 10-| and 20-cm depth| respectively. However| Q(10) and soil moisture are positively correlated with R-2 values of 0.81| 0.86| and 0.51 for soil temperature at 5-| 10-| and 20-cm depth| respectively. Q(10) values derived from temperatures at different soil depths also showed considerable variation along the vertical dimension. Q(10) had a large seasonal variation with the annual minimum occurring in midsummer and the annual maximum occurring in winter. Seasonal values of Q(10) depended closely on both soil temperature and moisture. Soil temperature and moisture explained 93% of the seasonal variation in Q(10). The spatial variation of Q(10) had significant influences on the estimation of soil CO2 efflux of the ecosystem. These variations tended to affect the seasonality of the Soil CO2 efflux more than the annual average. The variations of Q(10) and its dependence on soil moisture and temperature have important implications for regional and global ecosystem carbon modeling| in particular for predicting the responses of terrestrial ecosystems to future global warming. 5468,2001,3,4,Spatial distributions of the absolute CF and CF2 radical densities in high-density plasma employing low global warming potential fluorocarbon gases and precursors for film formation,Behaviors of gas| species in electron cyclotron resonance (ECR) plasmas employing low global warming potential fluorocarbon gases of hexafluorobutadiene (C4F6) and hexafluoropropene (C3F6) with unsaturated carbon bonds together with the conventional octafluorocyclobutane (c-C4F8) are investigated. The spatial distributions of the absolute CF and CF2 radical densities are measured by combining the single-path infrared diode laser| absorption spectroscopy and laser-induced fluorescence techniques. CF2 radicals have hollow-type distributions at all conditions in the ECR plasma reactor. However| the spatial distribution of the CF radical density differs greatly from that of the CF2 radical density. Behaviors of carbon atoms measured by vacuum ultraviolet absorption spectroscopy disagree with those of CF and CF2 radical densities. The behaviors of ion and fluorine species and the gas pressure in the plasma have been also evaluated. Fluorocarbon films with low dielectric constant of about 3.0 are deposited at a high rate of 600 nm/min at high microwave powers in CA and C4F6 plasmas. The distribution of deposition rates of the film on the 8 m. Si substrate shows hill-type distributions| which are quite different from the spatial distributions of CF and CF2 radical densities. Therefore| CF and CF2 radicals do not directly contribute greatly to the growth of fluorocarbon films in these plasmas. The behaviors of C atom densities indicate the similar tendency to those of deposition rates of films. On the basis of systematically measured results of species in the plasma and film deposition rate on Si wafer| it is clarified that the C atom and polymeric species contribute dominantly to the formation of films at| a high rate in low-pressure and high-density fluorocarbon plasmas. (C) 2001 American Vacuum Society. 5453,2001,5,4,Spiroplectinata| key benthic foraminifer genus for palaeoceanographic reconstruction of the Albian Lower Saxony Basin,This paper is focused on Albian Spiroplectinata| a morphologically unique| benthic| agglutinated foraminifer genus| and its application for reconstructing changes in the water masses within the Lower Saxony Basin. A new interpretation of microhabitat preferences and feeding habit for Spiroplectinata is proposed and discussed. Their functional morphology| composition of their tests| and their relationships with adherent foraminifera suggest that at least adult individuals of Spiroplectinata were epibenthic and were either suspension or deposit feeders. The suspension-feeding mode is favoured because this genus is associated with adherent suspension-feeding foraminifera and it does not correlate with other epibenthic deposit feeders. Spiroplectinata constructed an elongated uniserial terminal part| which probably facilitated an erect position to spread a reticulopodium well above the sediment/water interface. The distribution of this foraminifer can| therefore| be used here as a sensitive indicator for the existence of bottom currents. Four (or five) periods of intensified bottom water circulation around the Early/Middle Albian boundary (S-1)| Middle (S-2)| late Middle to earliest Late Albian (S-3| probably represents two intervals) and early Late Albian (S-4) are reconstructed and well marked by maxima of Spiroplectinata annectens| S. complanata| and Spiroplectinata sp. A. S. annectens is known from strata in the Western Tethys (i.e. in the Late Aptian and Early Albian) that are older than those in the 'Boreal' realm. Its first appearance in the Lower Saxony Basin occurs in the late Early Albian| followed by the first maximum just above the Early/Middle Albian boundary| and probably represents the main immigration event into the Lower Saxony Basin. This supports the idea that the deep water in the late Early to early Late Albian 'Boreal' epicontinental sea during 'the Spiroplectinata intervals' came from the Tethys and not from the polar regions. If one interprets the plankton/benthos foraminifera ratio as reflecting sea-level changes| it implies that sea-level rises may have been responsible for opening and/or deepening of 'Boreal'/Tethyan gateways that activated extensive exchange of water masses. This late Early Albian and early Late Albian 'invasion' of Tethyan water can be correlated with a general global warming| and shifting of climate zones. (C) 2001 Elsevier Science B.V. All rights reserved. 5484,2001,2,4,Stability of boreal forest stands during recent climate change: evidence from Landsat satellite imagery,Aim To detect possible expansion of boreal forest stands in response to recent warming. Previous modelling studies have concluded that major shifts in vegetation patterns| including changes in boreal forest extent| could arise during the next two centuries under global warming scenarios. However| field investigations of tree stands at ecotones have so far revealed little indication of stand response to warming during the last 100 years. This study uses a c. 25-year record of Landsat satellite observations to quantify changes in forest stand extent in two areas of northern Canada. Location Two regions of northern Canada| near Richmond Gulf| Quebec| and Great Slave Lake| north-west Territories. Methods Normalized-difference vegetation index (NDVI) plots across forest-tundra boundaries were obtained from radiometrically corrected Landsat imagery acquired during the 1970s and 1990s. These curves were evaluated to look for changes over the c. 25-year period related to forest stand expansion. Results Although forest-tundra boundaries could be clearly mapped from the satellite data| no obvious change in forest boundaries was apparent during the duration of the image time series| constraining recent geographical expansion rates to <200-300 m per century. Also| no evidence for local expansion of forest stands (e.g. within sheltered valleys) was found. Main conclusions The results are consistent with field observations| and suggest that| at the moment| boreal forest extents remain basically stable. This may reflect inherent lags between forest response and climate change| or competitive pressures between tree stands and surrounding tundra and herbaceous vegetation. 2959,2001,4,4,Statistical downscaling of GCM simulations to streamflow,A multi-tiered forecast procedure is employed to simulate real-time operational seasonal forecasts of categorized (below-normal| near-normal and above-normal) streamflow at the inlets of twelve dams of the Vaal and upper Tugela river catchments in South Africa. Forecasts are made for the December to February (DJF) season over an 8-year independent period from 1987/ 1988 to 1994/1995. A physically based model of the atmosphere system| known as a general circulation model (GCM)| is used to simulate atmospheric variability over southern Africa| the output of which is statistically downscaled to streamflow. The GCM used is the COLA T30| and is forced at the boundary with predicted monthly-mean global sea-surface temperatures. The monthly-mean sea-surface temperature fields are first predicted over lead-times of several months using a canonical correlation analysis (CCA) model. GCM simulations are then obtained for an area including most of southern Africa and adjacent oceans. The GCM simulations are downscaled to catchment level from coarse resolution gridded climate variables| using a perfect prognosis approach: bias-corrected GCM simulations are substituted into the perfect prognosis equations to provide the downscaled categorized streamflow forecasts. Although surface characteristics of each catchment that affect the variability of streamflow are not considered in the proposed downscaling system| successful forecasts of streamflow categories were obtained for some of the years forecast independently. The scheme's operational utility is thus demonstrated. albeit over short lead-times. (C) 2001 Elsevier Science B.V. All rights reserved. 5589,2001,4,1,Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols,Aerosols affect the Earth's temperature and climate by altering the radiative properties of the atmosphere. A large positive component of this radiative forcing from aerosols is due to black carbon-soot-that is released from the burning of fossil fuel and biomass| and| to a lesser extent| natural fires| but the exact forcing is affected by how black carbon is mixed with other aerosol constituents. From studies of aerosol radiative forcing| it is known that black carbon can exist in one of several possible mixing states; distinct from other aerosol particles (externally mixed(1-7)) or incorporated within them (internally mixed(1|3|7))| or a black-carbon core could be surrounded by a well mixed shell 7. But so far it has been assumed that aerosols exist predominantly as an external mixture. Here I simulate the evolution of the chemical composition of aerosols| finding that the mixing state and direct forcing of the black-carbon component approach those of an internal mixture| largely due to coagulation and growth of aerosol particles. This finding implies a higher positive forcing from black carbon than previously thought| suggesting that the warming effect from black carbon may nearly balance the net cooling effect of other anthropogenic aerosol constituents. The magnitude of the direct radiative forcing from black carbon itself exceeds that due to CH4| suggesting that black carbon may be the second most important component of global warming after CO2 in terms of direct forcing. 2970,2001,5,4,Studies in neotropical paleobotany. XV. A Mio-Pliocene palynoflora from the Eastern Cordillera| Bolivia: Implications for the uplift history of the Central Andes,An assemblage of 33 fossil pollen and spores| recovered from the 3600-m high Pislepampa locality of E. W. Berry| Eastern Cordillera| Bolivia| adds considerably to our knowledge of three aspects of the region in late Neogene time: (1) the paleovegetation| (2) the paleoclimate| and (3) the paleoelevation of the Central Andes. The plant microfossils recognized are Isoetes| Lycopodium (three types)| Cnemidaria| Cyathea (three types)| Grammitis| Hymenophyllum| Pteris| trilete fern spores (two types)| Danaea| monolete fern spores (four types)| Podocarpus| Gramineae| Palmae| Ilex| cf. Oreopanax| Cavanillesia| cf. Pereskia| Compositae (three types)| Ericaceae| Tetrorchidium| and unknowns (three types). The diversity of the Compositae suggest that this flora has a maximum age around the Miocene-Pliocene boundary| that is| 6-7 million years. All members of the paleocommunity presently grow in the bosque montano humedo (cloud forest) along the eastern slope of the Central Andes of Bolivia| which occurs between MATs (mean annual temperatures) of similar to 10 degrees and 20 degreesC. The Pislepampa flora probably represents the lower limits of this forest because the fossil leaves collected by Berry from the same locality all have entire margins| suggesting that the flora grew near the cloud forest-tropical forest transition. Presently| the lower limit of the cloud forest forest has MATs of similar to 20 degreesC| a mean annual precipitation between 1000 and 1500 mm| and that part containing most of the identified genera of fossil pollen is found at elevations similar to 1200-1400 m. These conditions are thus inferred for the Pislepampa flora; however| because of the uncertainty of the magnitude of global climate change and of possible changes in the ecological range of plant genera| we estimate an error of at least +/- 1000 m for the paleoelevation estimate. When the total uplift is corrected for probable amounts of erosionally driven isostatic rebound| the paleoelevation estimate suggests that from one-third to one-half of the uplift of the Eastern Cordillera had occurred by the beginning of the Pliocene. This estimate is consistent with other paleoelevation estimates from the Central Andes. 5452,2001,3,4,Study on CO2 global recycling system,In order to assist in finding ways to mitigate CO2 emission and to slow the depletion of fossil fuels we have established and evaluated a representative system| which consists of three technologies developed in our laboratory. These technologies were in CO2 recovery| hydrogen production and methanol synthesis and in addition we established the necessary supporting systems. Analysis of outline designs of the large scale renewable energy power generation system and this system and energy input for building plant| energy input for running plant has been conducted based on a case using this system for a 1000-MW coal fired power plant| followed by an evaluation of the material balance and energy balance. The results are as follows. Energy efficiency is 34%| the CO2 reduction rate is 41%| the balance ratio of the energy and CO2 of the system is 2.2 and 1.8| respectively| on the assumption that the primary renewable energy is solar thermal power generation| the stationary CO2 emission source is a coal-fired power plant and the generation efficiency of the methanol power plant is 60%. By adopting the system| 3.7 million tons of CO2 can be recovered| approximately 2.7 million tons of methanol can be produced| and 15.4 billion kWh of electricity can be generated per year. Compared to generating all electrical power using only coal| approximately 2.6 million tons of coal per year can be saved and approximately 2.15 million tons of CO2 emission can be reduced. Therefore| it is clearly revealed that this system would be effective to reduce CO2 emissions and to utilize renewable energy. (C) 2001 Elsevier Science B.V. All rights reserved. 2995,2001,2,4,Subaerial river bank erosion processes and their interaction with other bank erosion mechanisms on the river arrow| Warwickshire| UK,River bank erosion occurs primarily through a combination of three mechanisms: mass failure| fluvial entrainment| and subaerial weakening and weathering. Subaerial processes are often viewed as 'preparatory' processes| weakening the bank face prior to fluvial erosion. Within a river basin downstream process 'domains' occur| with subaerial processes dominating the upper reaches| fluvial erosion the middle| and mass failure the lower reaches of a river. The aim of this paper is to demonstrate that (a) subaerial processes may be underestimated as an erosive agent. and (b) process dominance has a temporal| as well as spatial| aspect. Bank erosion on the River Arrow| Warwickshire| UK| was monitored for 16 months (December 1996 to March 1998) using erosion pins. Variations in the rate and aerial extent of erosion are considered with reference to meteorological data. Throughout the first 15 months all erosion recorded was subaerial. resulting in up to 181 mm a(-1) of bank retreat| compared with 13 to 27 mm a(-1) reported by previous researchers. While the role of subaerial processes as 'preparatory' is not contended| it is suggested that such processes can also be erosive. The three bank erosion mechanisms operate at different levels of magnitude and frequency| and the River Arrow data demonstrate this. Thus the concept of process dominance has a temporal| as well as spatial aspect. particularly over the short time-periods often used for studying processes in the field| Perception of the relative efficacy of each erosive mechanism will therefore be influenced by the temporal scale at which the bank is considered. With the advent of global climate change. both these magnitude-frequency characteristics and the consequent interaction of bank erosion mechanisms may alter. It is therefore likely that recognition of this temporal aspect of process dominance will become increasingly important to studies of bank erosion processes. Copyright (C) 2001 John Wiley & Sons| Ltd. 5500,2001,3,4,Surface emission of landfill gas from solid waste landfill,The surface emission of landfill gas (LFG) was studied to estimate the amount of LFG efflux from solid waste landfills using an air flux chamber. LFG efflux increased as atmospheric temperature increased during the day| and the same pattern for the surface emission was observed for the change of seasons. LFG efflux rate decreased from summer through winter. The average LFG efflux rates of winter| spring and summer were 0.1584| 0.3013 and 0.8597 m(3) m(-2) h(-1) respectively. The total amount of surface emission was calculated based on the seasonal LFG efflux rate and the landfill surface area. From the estimates of LFG generation| it is expected that about 30% of the generated LFG may be released through the surface without extraction process. As forced extraction with a blower proceeded| the extraction well pressure decreased from 1100 to -100 mm H2O| and the LFG surface efflux decreased markedly above 80%. Thus| the utilization of LFG by forced extraction would be the good solution for global warming and air pollution by LFG. (C) 2001 Elsevier Science Ltd. All rights reserved. 5612,2001,4,4,Surface energy- and water balance in a high-arctic environment in NE Greenland,Within the framework of the European LAPP-project (Land Arctic Physical Processes) and as part of the Danish Research Council's Polar Programme| studies on water and surface energy balance in NE Greenland were conducted in 1996 and 1997. Eddy correlation measurements of water vapour and sensible heat fluxes above the three dominant vegetation types: fen| willow snowbed| and heath were conducted for the entire growing season. This was supplemented by measurements of evaporation from snow covered areas and from a small pond. The evapotranspiration was found to be relatively high with the maximum from the fen (approximate to 86 per season). For the two other vegetation types the evapotranspiration was less| for heath 61 mm per season| while willow snowbed had evaporation rates on intermediate level. By use of the Penman-Monteith equation it was possible to estimate the altitude dependence of the evapotranspiration and calculate the annual evaporation for the whole area to 80 mm per year. By applying a bucket model the evaporation was found to be in accordance with changes in soil moisture as monitored with TDR. The observed surface water balance was compared to river discharge| which shows a glacio-nival regime with an early spring flow (June)| determined by the snow melt in the main valley and an July-August maximum determined by melt on higher plateau areas. When balancing the individual hydrological components an annual deficit of 180 mm was observed| but it was found that this deficit could be reduced by correcting for aerodynamic and altitude effects on the precipitation. Finally some of the possible consequences of a global warming is discussed in relation to the water and energy balance in the high-arctic ecosystem. 5495,2001,4,3,Surface measurements of global warming causing atmospheric constituents in Korea,The expansion of the industrial economy and the increase of population in Northeast Asian countries have caused much interest in climate monitoring related to global warming. However| new techniques and better platforms for the measurement of global warming and regional databases are still old-fashioned and are not being developed sufficiently. With respect to this agenda| since 1993| at the request of the World Meteorological Organization (WMO)| to monitor functions of global warming| the Korea Meteorological Administration (KMA) has set up a Global Atmospheric Watch (GAW) Station on the western coast of Korea (Anmyun-do) and has been actively monitoring global warming over Northeast Asia. In addition| atmospheric carbon dioxide (CO2) has been measured for a similar KMA global warming program at Kosan| Cheju Island since 1990. Aerosol and radiation have also been measured at both sites as well as in Seoul. The observations have been analyzed using diagnostics of climate change in Northeast Asia and also have been internationally compared. Results indicate that greenhouse gases are in good statistic agreement with the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) long-term trends of monthly mean concentrations and seasonal cycles. Atmospheric particulate matter has also been analyzed for particular Asian types in terms of optical depth| number concentration and size distribution. 5441,2001,2,4,Survival and development of Aedes aegypti and Aedes albopictus (Diptera : Culicidae) larvae under a seasonally changing environment in Nagasaki| Japan,Survival and development of larvae of Aedes aegypti (L.) and Aedes albopictus (Skuse) were examined under field conditions on the campus of Nagasaki University School of Medicine| Nagasaki| Japan| to explore the possibility of the establishment of Ae. aegypti in Kyusyu| southern Japan| Exposure experiments with hatched larvae were conducted 11 times at about 1-mo intervals from January 1998 to January 1999. In both species| larvae could develop to adults under field conditions from April to November| but not in January| February| and December 1998. In March 1998| only Ae. albopictus could develop to adults. The results suggest that there are differences in the resistance of hatched larvae to low temperatures between Ae. aegypti and Ae. albopictus and a threshold air temperature of larval development below 10 degreesC for both species. To estimate the threshold temperatures of larval development| the relationships between the average air temperature and the developmental rate observed in March-November 1998 were analyzed by linear regression analysis. The estimated threshold air temperatures for Ae. aegypti were 8.52 and 9.45 degreesC for females and males| respectively| and were higher than those of Ae. albopictus. A clear seasonal change was also observed in the body size of pupae. In both species| body size was largest at the beginning of the breeding season and continuously became gradually smaller until July. The results were compared with those from previous field studies in Nagasaki and the possibility of the establishment of Ae. aegypti in Nagasaki| Japan| is discussed from the viewpoint of adaptive life history to seasonally changing environments. 3019,2001,5,4,Synchronous tropical South China Sea SST change and Greenland warming during deglaciation,The tropical ocean plays a major role in global climate| It is therefore crucial to establish the precise phase between tropical and high-latitude climate variability during past abrupt climate events in order to gain insight into the mechanisms of global climate change. Here we present alkenone sea surface temperature (SST) records from the tropical South China Sea that show an abrupt temperature increase of at least 1 degreesC at the end of the Last glacial period. Within the recognized dating uncertainties| this SST increase is synchronous with the Bolling warming observed at 14.6 thousand years ago in the Greenland Ice Sheet Project 2 ice core. 3002,2001,2,4,Synthesis and analysis of biomass and net primary productivity in Chinese forests,An extant dataset is presented on biomass and net primary productivity (NPP) of 6 forest biomes| including 690 stands from 17 forest types of China. Data on latitude| longitude| elevation| field measurements of stand age| leaf area index (LAI) and total biomass were collected for 29 provinces from forestry inventory data of the Forestry Ministry of China| as well as a wide range of published literature. The individual site-based NPP was estimated from field biomass measurements based on a common methodology. The range of measured LAI| biomass and estimated NPP is from 0.17 to 41.78 m(2) m(-2) (mean = 8.94)| from 31.14 to 1569.85 t ha(-1) (means = 185.41)| and from 2.41 to 40.27 t ha(-1) yr(-1) (mean = 14.4)| respectively. Analyses and synthesis between NPP and environmental factors showed that| in eastern China| NPP of forests increases from north to south| whereas NPP of major forests in southern China decreases in relation to longitude from east to west. In mountainous areas| the distribution of NPP is related to elevation. On a regional basis| the NPP of Chinese forests is highly correlated with annual mean temperature and rainfall| as well as the annual potential evapotranspiration| especially on the basis of site-based comparison. Strong positive correlation also existed between NPP and growing degree-days on a 0 degreesC base and on a 5 degreesC base. These all indicated that temperature and moisture are the dominant factors controlling the spatial distribution of NPP in China. A site-based comparison between estimated NPP and NPP modelled by the BIOME3 model showed a fair agreement with a linear regression. A higher correlation occurred in the forest-based comparison between estimated and modelled NPP| whereas the highest correlation was found in the plant functional type (PFT)-based comparison. However| there are many limitations in the current data set and methodologies| such as the lack of some components of biomass and NPP| especially with respect to root production. More detailed field measurements and methodologies covering all components of NPP should be addressed in China in the future. 2983,2001,4,4,Temperature effects on the dynamics of Aedes albopictus (Diptera : Culicidae) populations in the laboratory,We investigated how constant temperatures of 22| 24| and 26 degreesC experienced across the full life cycle affected the dynamics of caged populations of Aedes albopictus (Skuse). All cages were equipped with plastic beakers that served as sites for oviposition and larval development. We measured the per capita daily mortality and emergence rates of the adults and size of adult females| and estimated the intrinsic rate of increase (r) and asymptotic density (K) for each adult population. populations at 26 degreesC had greater intrinsic rates of increase and lower asymptotic densities than populations at 22 and 24 degreesC. Populations at high temperatures initially had greater daily. per capita emergence rates| and steeper. declines in per capita emergence rate as density increased over tire course of the experiment| There was no temperature effect on the size of adult females nor on the per capita daily mortality rate of adults. Results indicated that populations of Ae. albopictus occurring in regions with relatively high summer temperatures are likely to have hiyh rates of population growth with populations of adults peaking early in the season. These populations mn)l attain relatively. low peak densities of adults. Populations occurring in regions with low summer temperatures are likely to experience slow| steady production of adults throughout the season with population size peaking later in the season| and may attain higher peal| densities of adults. Nigh temperature conditions| associated with climate change| may increase the rate of spread of Ae| albopictus by increasing rates of increase and by. enhancing colonization due to rapid population growth. 5588,2001,3,4,Temperature resolved modeling of plasma abatement of perfluorinated compounds,Plasma abatement of perfluorinated compounds (PFCs) is a technology of increasing interest as the semiconductor industry seeks to reduce emission of these global warming gases. This article reports a simulation of point-of-use plasma abatement| in which a high density abatement plasma is placed between the process tool turbomolecular pump and the roughing pump. Oxygen is added to convert the feed PFCs to oxidized species that can then be scrubbed downstream. The simulation is used to examine the transport and chemistry that occurs in these plasmas. Two-dimensional plasma and neutral transport models are coupled to a description of gas and surface plasma chemistry. The simulation shows that| at high electron density and low neutral density| abatement of CF4 is governed by electron impact dissociation. Both the model and experimental measurements predict high peak neutral temperatures (> 1500 K) that play a large role in determining the characteristics of these plasmas. (C) 2001 American Institute of Physics. 5592,2001,2,4,Temperature responses of carbon mineralization in conifer forest soils from different regional climates incubated under standard laboratory conditions,C-14-labelled straw was mixed with soils collected from seven coniferous forests located on a climatic gradient in Western Europe ranging from boreal to Mediterranean conditions. The soils were incubated in the laboratory at 4 degrees| 10 degrees| 16 degrees| 23 degrees and 30 degreesC with constant moisture over 550 days. The temperature coefficient (Q(10)) for straw carbon mineralization decreased with increasing incubation temperatures. This was a characteristic of all the soils with a difference of two Q(10) units between the 4-10 degrees and the 23-30 degreesC temperature ranges. It was also found that the magnitude of the temperature response function was related to the period of soil incubation. Initial temperature responses of microbial communities were different to those shown after a long period of laboratory incubation and may have reflected shifts in microbial species composition in response to changes in the temperature regime. The rapid exhaustion of the labile fractions of the decomposing material at higher temperatures could also lead to underestimation of the temperature sensitivity of soils unless estimated for carbon pools of similar qualities. Finally| the thermal optima for the organic soil horizons (Of and Oh) were lower than 30 degreesC even after 550 days of incubation. It was concluded that these responses could not be attributed to microbial physiological adaptations| but rather to the rates at which recalcitrant microbial secondary products were formed at higher temperatures. The implication of these variable temperature responses of soil materials is discussed in relation to modelling potential effects of global warming. 3003,2001,5,4,Terminal Pleistocene/early Holocene environmental change at the sunshine locality| north-central Nevada| USA,Sedimentological| faunal| and archaeological investigations at the Sunshine Locality| Long Valley| Nevada reveal a history of human adaptation and environmental change at the last glacial-interglacial transition in North America's north-central Great Basin. The locality contains a suite of lacustrine| alluvial| and eolian deposits associated with fluvially reworked faunal remains and Paleoindian artifacts. Radiocarbon-dated stratigraphy indicates a history of receding pluvial lake levels followed by alluvial down-cutting and subsequent valley filling with marsh-like conditions at the end of the Pleistocene. A period of alluvial deposition and shallow water tables (9|800 to 11|000 C-14 yr B.P.) correlates to the Younger Dryas. Subsequent drier conditions and reduced surface runoff mark the early Holocene; sand dunes replace wetlands by 8|000 C-14 Yr B.P. The stratigraphy at Sunshine is similar to sites located 400 km south and supports regional climatic synchroneity in the central and southern Great Basin during the terminal Pleistocene/early Holocene| Given regional climate change and recurrent geomorphic settings comparable to Sunshine| we believe that there is a high potential for buried Paleoindian features in primary association with extinct fauna elsewhere in the region yet to be discovered due to limited stratigraphic exposure and consequent low visibility. (C) 2001 University of Washington. 5426,2001,2,4,The biology of larvae from the reef coral Porites astreoides| and their response to temperature disturbances,Pelagic larvae play a fundamental role in the life history of virtually all scleractinian corals| yet much of their biology remains unexplored. One aspect of coral larvae - their response to temperature perturbations has potentially important consequences for understanding the effects of global warming and El Nino-Southern Oscillation events on coral recruitment. The present study tests the effects of temperature perturbations on coral larvae using Porites astreoides larvae as a model system. In June 1999| larvae were collected from 18 m depth on Conch Reef| Florida| and incubated at ambient (28 degreesC)| depressed (26 degreesC)| and elevated (33 degreesC) temperatures in outdoor tanks shaded from direct sunlight. Treatments were repeated with new larvae every 24 h| and treatment effects quantified as larval motility| mortality. metamorphosis and metabolism. Elevated temperature significantly increased mortality and metamorphosis| and a similar trend was observed at the reduced temperature| although this was not significant. Neither elevated nor reduced temperatures affected larval motility. Gross photosynthesis (P) was significantly depressed by elevated and reduced temperatures| and respiration (R) varied proportionately with temperature (Q(10)approximate to2)| although this effect was not statistically Significant. At the highest temperature the P/R ratio declined to < 1| indicating that thermal stress reduces the potential for autotrophy. Together| these results suggest that elevated temperatures affect coral larvae by depressing photosynthesis and creating an energy shortage| which ultimately could reduce recruitment (by increasing mortality)| shorten larval longevity and favor premature metamorphosis. An unexpected finding was that larvae differed physiologically among release dates. Although preliminary| this suggests that larval fitness in Porites spp. may vary depending on the day of release| a phenomenon that could have significant ramifications with respect to the population structure of adults. 2956,2001,3,4,The challenge of deep ocean drilling for natural gas hydrate,Large reservoirs of natural gas hydrate have been sampled extensively by past DSDP| ODP| and other scientific ocean drilling. Gas hydrate is an ice-like solid consisting of gas molecules| commonly methane| trapped in a cage of water molecules. Global estimates of the methane content of natural gas hydrate are very large| potentially enormous. Such large quantities of gas hydrate could be important as a clean energy source| as a control in global climate| and as a factor in seafloor slumps and slides. Gas hydrate occurs only in water depths greater than about 600 m at temperate latitudes| but occurs on land and in shallow water in the Arctic. The formation mechanisms of gas hydrates are only partly understood. Gas hydrate appears to be formed usually by migrating fluids carrying biologically generated methane upward to regions of sufficiently low temperature and high pressure where the hydrate is stable. Quantitative aspects of this formation model need testing| however| and questions remain about the sources and sinks for methane| and the amount that can reach the atmosphere. In Canada| gas hydrates are found on most of its continental margins| notably on the continental slope off Vancouver Island and in the Mackenzie Delta-Beaufort Sea region. A drilling program off Vancouver Island would examine gas hydrates in a well-studied accretionary sedimentary wedge; such sediments appear to be the most common environment in which hydrates are found globally. Drilling for gas hydrate offshore in the Canadian Arctic| perhaps using an alternative drilling platform| would complement a current onshore Arctic gas hydrate drilling program in the permafrost environment. The Arctic land and shallow sea hydrate are important because such hydrate is especially susceptible to global climate change. 2990,2001,2,4,The compositions| sources| and size distribution of the dust storm from China in spring of 2000 and its impact on the global environment,The average mass concentration of the aerosols in Beijing during the dust storm in the spring of 2000 was similar to 6000 mug . m(-3|) similar to 30 times as high as that in the non-dust storm days. The enrichment factors of the pollution elements As| W and Se were higher than those in the non-dust storm days. This indicated that As| Sb and Se resulted from the pollution sources of those areas| through which the dust storm passed during their long-range transport| in addition to the local pollution sources in Beijing| The enrichment factors of the Pb| Zn| Cd and Cu were much less than those in the cion-dust storm days| suggesting that the local pollution sources in Beijing area contributed to them mostly| The enrichment factors of elements Al| Fe| Sc| Mn| Na| Ni| Cr| V and Co were close to 1| showing that these elements originated from crust| The concentration of S in the dust storm was similar to 10 mug . m(-3)| 4 times as high as that in non-dust storm. S in the aerosols resulted from the adsorption of gaseous SO2 and the consequent transformation on it. The aerosols of the dust storm contained 16.1% and 76.9% of fine particles with the sizes less than 2.1 and 9.0 mum| respectively| while it had a large number of coarse particles| It was noted that a considerable portion of Fe(II) was detected from the dust storm. Fe(II) could easily dissolve in seawater to be nutrient for phytoplankton and would lead to the increase of the emission of dimethylsulfide (DMS) from the ocean. The feedbacks of Fe coupled with S in atmosphere might be the important mechanism that would affect the primary productivity in Pacific and/or the global climate change. 5670,2001,3,4,The development and improvement of energy efficient refrigerators,The growing concerns over global warming due to greenhouse gas emissions have pushed the appliance industry to further improve energy efficiency of its products. Refrigerator-freezers (RF)| as one of the major home appliances| consume about one-fifth of the electricity in a household| and its life expectancy could be as long as 10-15 years. In response to future stricter regulations| several design options were considered For improving the energy efficiency of a conventionally designed domestic RF. The options| such as insulation improvements obtained by using vacuum insulation panels (VIPs)| energy saving defrost control| and high-efficiency compressors were examined in a prototype RF. The energy consumption of the original 1997 production refrigerator-freezer was selected as the baseline in order to compare the measured energy savings of each option and the combined options on the prototype refrigerator-freezer. This study has reached a goal to develop a prototype that has an energy consumption rate of 20% less than the baseline model. 2966,2001,4,4,The effect of sea spray evaporation on tropical cyclone boundary layer structure and intensity,Strong winds in a tropical cyclone over the ocean can produce high seas with substantial amounts of spray in the lower part of the atmospheric boundary layer. The effects that the evaporation of this sea spray may have on the transfer of energy between the ocean and the atmosphere| and consequent effects on the boundary layer structure| cumulus convection| and the evolution of the tropical cyclone| are largely unknown. In this study| a high-resolution tropical cyclone model with explicit cloud microphysics| developed by Y. Wang| has been used to study these potential effects. The sea spray evaporation is incorporated into the model by two bulk parameterization schemes with quite different properties. The numerical results show that inclusion of the Fairall et at. sea spray parameterization increases the direct sensible heat flux from the ocean by about 70%| but has little effect on the direct latent heat flux. Sea spray itself causes a sensible heat flux of only about 6% of the direct sensible heat flux| while it contributes a latent heat flux by evaporation of sea spray droplets by 60%-70% of the direct latent heat flux. As a result| the total enthalpy flux with sea spray evaporation increases by about 20%| while the net contribution by sea spray is only about 1.5% of the total enthalpy flux. Consistent with this| the intensity of the model tropical cyclone is moderately increased by 8% in the maximum wind speed by the introduction of sea spray. The lower atmosphere becomes cooler and moister due to the evaporation of sea spray| which is supported by the available observations. The cooling in the surface layer further modifies the boundary layer structure and the activity of convection| especially in the near-core region where the highest concentration of sea spray exists. On the other hand| with the Andreas and DeCosmo parameterization scheme| the intensity of the model tropical cyclone is increased by 25% in maximum wind speed. This dramatic increase in the model tropical cyclone intensity is due to both the large net sensible heat flux and the latent heat flux associated with the effect of sea spray by this parameterization scheme. The net upward sensible heat flux warms the air near the surface and results in a near-isotherm al surface layer in the near-core environment under the tropical cyclone. Such a structure| however| is not supported by the available observations| which the authors argue is not physically realistic. The radically different results with this scheme are due to the unusual way that the feedbacks between direct and spray-mediated fluxes are handled within the parameterization. 5421,2001,2,4,The effects of climate change on Merriam's kangaroo rat| Dipodomys merriami,We examined the relationship between body size of Dipodomys merriami and specific climate variables for the years 1989 through 1996 at the Sevilleta LTER Station. Earlier work demonstrated a 2-3 degreesC increase in both summer and winter temperatures at Sevilleta over this time period. In that study| Neotoma albigula's adult mean body mass decreased as temperature increased. Dipodomys merriami's adult mean body mass differed significantly among years for both sexes but there was no trend across years. There was also no relationship to climate variables. Abundance showed a positive relationship with one axis of a PCA of the correlated climate variables. (C) 2001 Academic Press. 5409,2001,3,3,The evaluation of hexafluorobenzene as an environmentally benign dielectric etch chemistry,Hexafluorobenzene was evaluated as an alternative chemistry for dielectric etch applications in a high density plasma etch chamber with reduced global warming emissions. Processes based on hexafluorobenzene exhibited global warming emissions reductions as high as 97% compared to a C3F8-based process| which is the greatest reductions level of any alternative chemistry examined to date on this tool. Using hexafluorobenzene| it is possible to operate in a regime of high etch rate and high polymerization. There are several issues| however| that need to be addressed if this chemistry is to be used for high performance dielectric etching. This material is a liquid at room temperature| which makes it difficult to deliver process gas to the chamber. In addition| this chemistry is highly polymerizing| resulting in excess polymer deposition on chamber walls leading to significant process variability for standard chamber clean times. Significantly longer chamber clean times were required between each etch to remove the excess polymer. (C) 2001 The Electrochemical Society. 5539,2001,2,4,The frost resistance of ericoid heath plants in the British Isles in relation to their biogeography,Aim To determine whether rare British ericoid heaths are restricted to the oceanic fringes of south-western England and western Ireland because of their sensitivity to frost. Location The Wirral Peninsula| Cheshire| England. Shoots of the common heaths (Calluna vulgaris (L.) Hull| Erica tetralix L.| Erica cinerea L.) were obtained from Thurstaston Heath and those of the rarer heaths (E. mackaiana Bab.| E. ciliaris L.| E. erigena R. Ross and E. vagans L.) from collections of known provenance in Ness Gardens. Methods Frost resistance of cut shoots was determined at approximately monthly intervals between February 1994 and March 1995. Shoots were exposed to a range of freezing temperatures and scored for damage. Freezing resistance was determined as the temperature that caused 50% damage to the shoots. Results The frost resistance of the common heaths was in accord with their geographical distribution. Calluna vulgaris and E. tetralix extend furthest north and east in Europe and developed the greatest frost resistance in winter ( < -20We analyse the new ISCCP (International Satellite Cloud Climatology Project) D2 cloud data to ascertain whether or not a connection between cosmic ray flux and cloud cover exists. Our results indicate that only the low-level cloud follows solar activity over the full period| 1983-1994. Using several proxies for solar activity and the radiative forcing for the ISCCP cloud types| we estimate the possible impact that such a solar-terrestrial connection may have on climate. We conclude that| possibly excluding the most recent decades| much of the warming of the past century can be quantitatively accounted for by the direct and indirect effects of solar activity.
3045,2001,3,4,The potential impact of conservation practices in US agriculture on global climate change,Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This| in turn| will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual| site-specific conservation practices on changes in soil organic carbon. There is a general absence| however| of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage| the Conservation Reserve Program| and conservation buffer strips to change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices| it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million metric tons. By 2008| there will be an increase of about 25 percent. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration| there are a number of policy options that can be pursued. (C) 2001 by The Haworth Press| Inc. All rights reserved. 5548,2001,2,4,The potential impacts of climate variability and change on air pollution-related health effects in the United States,Climate change may affect exposures to air pollutants by affecting weather| anthropogenic emissions| and biogenic emissions and by changing the distribution and types of airborne allergens. Local temperature| precipitation| clouds| atmospheric water vapor. wind speed| and wind direction influence atmospheric chemical processes| and interactions occur between local and global-scale environments. If the climate becomes warmer and more variable| air quality is likely to be affected. However| the specific types of change (i.e.| local| regional| or global)| the direction of change in a particular location (i.e.| positive or negative)| and the magnitude of change in air quality that may be attributable to climate change are a matter of speculation| based on extrapolating present understanding to future scenarios. There is already extensive evidence on the health effects of air pollution. Ground-level ozone can exacerbate chronic respiratory diseases and cause short-term reductions in lung function. Exposure to particulate matter can aggravate chronic respiratory and cardiovascular diseases| alter host defenses| damage lung tissue| lead to premature death| and possibly contribute to cancer. Health effects of exposures to carbon monoxide| sulfur dioxide| and nitrogen dioxide can include reduced work capacity| aggravation of existing cardiovascular diseases| effects on pulmonary function| respiratory illnesses| lung irritation| and alterations in the lung's defense systems. Adaptations to climate change should include ensuring responsiveness of air quality protection programs to changing pollution levels. Research needs include basic atmospheric science work on the association between weather and air pollutants; improving air pollution models and their linkage with climate change scenarios; and closing gaps in the understanding of exposure patterns and health effects. 5547,2001,2,4,The potential impacts of climate variability and change on health impacts of extreme weather events in the United States,Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change? may alter the frequency| timing| intensity| and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events| including precipitation during hurricanes| raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects| mediated by changes in ecologic systems and public health infrastructure| also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes| warning systems| disaster policies| evacuation plans| and relief efforts. There are many federal| state| and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation. 5546,2001,2,4,The potential impacts of climate variability and change on temperature-related morbidity and mortality in the United States,Heat and heat waves are projected to increase in severity and frequency with increasing global mean temperatures. Studies in urban areas show an association between increases in mortality and increases in heat| measured by maximum or minimum temperature| heat index| and sometimes| other weather conditions. Health effects associated with exposure to extreme and prolonged heat appear to be related to environmental temperatures above those to which the population is accustomed. Models of weather-mortality relationships indicate that populations in northeastern and midwestern U.S. cities are likely to experience the greatest number of illnesses and deaths in response to changes in summer temperature. Physiologic and behavioral adaptations may reduce morbidity and mortality. Within heat-sensitive regions| urban populations are the most vulnerable to adverse heat-related health outcomes. The elderly| young children| the poor| and people who are bedridden or are on certain medications are at particular risk. Heat-related illnesses and deaths are largely preventable through behavioral adaptations| including the use of air conditioning and increased fluid intake. Overall death rates are higher in winter than in summer| and it is possible that milder winters could reduce deaths in winter months. However| the relationship between winter weather and mortality is difficult to interpret. Other adaptation measures include heat emergency plans| warning systems| and illness management plans. Research is needed to identify critical weather parameters| the associations between beat and nonfatal illnesses| the evaluation of implemented heat response plans| and the effectiveness of urban design in reducing heat retention. 5594,2001,3,3,The present| past| and future contributions to global warming of CO2 emissions from fuels,The objective of this paper is to emphasize the responsibility of developed countries to implement the Climate Convention| as well as the role of developing countries in CO2 emissions control while sustaining their rights to increase energy consumption per capita during the development process. It is shown that the growth in CO2 emissions from fossil fuel consumption in North America| excluding Mexico| from 1990 to 1996 was 3.7 times higher than that of Latin America in absolute terms. The cumulative contribution to global warming| expressed as the mass of the gas multiplied by time (GtCy)| can be calculated as the integration of the atmospheric concentration of the emitted gas along time| with a weight function in the integrand to simulate the climate response. To simulate climate response| we used the superposition of exponential decay functions with different decay constants. The historical contributions of the OECD countries| the Eastern European countries and the ex-Soviet Union| and from all developing countries are considered. The future contributions are computed in three scenarios. All of them show that emissions from Non-Annex I countries will become higher than those of Annex I countries soon after 2010| while the curves of atmospheric concentration will cross one another later| not much before 2050| and the respective contributions to global temperature increase will cross about 2090. 3023,2001,4,4,The role of biota in global climate change,The problem of global climate change is analyzed in the context of the balance of interdependent biotic sources and reservoirs of greenhouse gases in the continental part of northern Eurasia. Current problems are identified and the prospects for further studies of the problem are outlined. 5402,2001,2,2,The science of global warming,There is strong scientific evidence that the average temperature of the earth's surface is rising as a result of the increased concentration of carbon dioxide and other greenhouse gases in the atmosphere owing to human activities| especially the burning of fossil fuels| coal| oil| and gas. This global warming will lead to substantial changes of climate| many of which will impact human communities in deleterious ways. In terms of the likely global pattern of climate change over the twenty-first century| in the absence of any mitigating action the global average temperature is likely to rise by between about 1-5 and 5-5degreesC and sea level by about half a metre (range 0(.)1-0(.)9 m). The hydrological cycle is likely to be more intense (leading in some places to more frequent and more intense floods and droughts) and the rate of climate change is likely to be substantially greater than the earth has experienced over at least the last ten thousand years. It is particularly to this rapid rate of change that it will be difficult for many ecosystems and for humans to adapt. Action has been taken by the world's scientists through the Intergovernmental Panel on Climate Change to assess as thoroughly as possible knowledge regarding the basic science and the impacts| including an assessment of the uncertainties. The world's governments have also taken action in setting up the Framework Convention on Climate Change (FCCC) at the Earth Summit in 1992 and at subsequent meetings of the parties to that convention| especially that at Kyoto in 1997. In order to mitigate climate change the FCCC in its article 2 has set the objective of stabilisation of the concentration of greenhouse gases in the atmosphere at a level and on a timescale consistent with the needs both of the environment and of sustainable development. Such stabilisation will eventually demand severe cuts in global emissions| for instance of carbon dioxide| to levels well below today's by the second half of the twenty-first century. To achieve the required reductions in the emissions of carbon dioxide| three possibilities are available| to sequester carbon dioxide resulting from the burning of fossil fuels rather than releasing it to the atmosphere| to become much more efficient in the generation and use of energy| and to provide for energy supply from non-fossiI fuel sources. This article will summarise the science of climate change including the evidence for it and will describe the main impacts| the actions taken so far| and the further actions that are likely to be necessary to mitigate climate change. 3012,2001,2,3,The sensitivity of Australian fire danger to climate change,Global climate change| such as that due to the proposed enhanced greenhouse effect| is likely to have a significant effect on biosphere-atmosphere interactions| including bushfire regimes. This study quantifies the possible impact of climate change on fire regimes by estimating changes in fire weather and the McArthur Forest Fire Danger Index (FDI)| an index that is used throughout Australia to estimate fire danger. The CSIRO 9-level general circulation model (CSIRO9 GCM) is used to simulate daily and seasonal fire danger for the present Australian climate and for a doubled-CO(2) climate. The impact assessment includes validation of the GCMs daily control simulation and the derivation of 'correction factors' which improve the accuracy of the fire danger simulation. In summary| the general impact of doubled-CO(2) is to increase fire danger at all sites by increasing the number of days of very high and extreme fire danger. Seasonal fire danger responds most to the large CO(2)-induced changes in maximum temperature. 5486,2001,3,3,The source and abatement of nitrous oxide emissions produced from the aerobic treatment of pig slurry to remove surplus nitrogen,The removal of surplus nitrogen from pig slurry can be necessary in order to avoid pollution such as nitrate leaching. However| the treatment itself can create significant pollution; up to 20% of the removed slurry nitrogen has been shown to be released as nitrous oxide (N2O)| which contributes to global warming and the breakdown of the ozone in the stratosphere. Avoiding such emission requires conditions that encourage the complete conversion of the nitrogen to the environmentally safe di-nitrogen gas (N-2)| and a clear understanding of the underlying biochemistry; for example| whether the nitrous oxide is the bi-product of incomplete nitrification (chemical oxidation) or denitrification (chemical reduction). The stable isotope of nitrogen (N-15) was used in this investigation as a label. Results indicated a new route for substantial release of N2O: via nitrification (rather than denitrification)| caused by a combination of high aeration levels and the presence of nitrification products. Sequential aeration| which leads to a cycling between nitrification and complete denitrification| was proposed as an abatement in view of this new mechanism. This process achieved 89% removal of ammoniacal nitrogen in laboratory scale treatment| with 94% of the nitrogen removed in the form of N-2. These findings suggest that the possibility of N2O emissions from nitrification be considered in the design of treatment schemes. Increased aeration would be the intuitive response to incomplete nitrification. However| the results of this study suggested that although this response can increase nitrogen removal| this may be as N2O rather than N-2. 5628,2001,4,4,The surface radiative forcing of nitric acid for northern mid-latitudes,Ground-based| high-resolution measurements of downward atmospheric thermal emission spectra are reported for a northern mid-latitude location for summer and winter conditions. These measurements clearly show the presence of the 11.3-mum thermal emission band of nitric acid situated between 850-920 cm(-1). By using the FASCOD3 line-by-line radiation code to simulate the background thermal emission| the measured seasonally averaged surface radiative forcing due to nitric acid is determined to be 0.055 W m(-2) +/- 15%. The zenith column amounts of nitric acid are found to vary between 7.9 x 10(15) and 1.1 x 10(16) molecules cm(-2) +/- 15%. An estimation is made of the contribution of nitric acid to the direct radiative forcing of the Earth's surface since pre-industrial times for northern mid-latitudes. This work suggests that nitric acid may play a role that is comparable to that of other greenhouse gases| such as CFC-11| in the forcing of the Earth's climate system. Under polluted conditions| nitric acid may contribute about half of the radiative forcing that is currently associated with tropospheric ozone. (C) 2000 Elsevier Science Ltd. All rights reserved. 3043,2001,4,4,The use of decision support tools in participatory river basin management,There are growing demands for effective public participation in river basin management. These are posed among others by the proposed EU Water Framework Directive as well as international conventions and policy documents. The demands will raise a need for guidance on exactly how the public is to be involved. In public participation 'decision support tools' (DST) and integrated modelling can have a role to play. Many computer tools not only can serve as tools for analysis for experts| but also as vehicles for communication| training| forecasting and experimentation. Illustrated by selected examples of software a range of tools and their potential applications are presented. Essential for the added-value of computer tools in stakeholder participation| in comparison to other methods like expert presentations| fact sheets| etc.| is the way they are used. Lessons can be drawn from projects where computer tools were used in other policy areas. Within an European research project on energy and climate policy (ULYSSES) integrated models on global climate change were used in integrated assessment (IA) focus groups. A web-based tutorial for the use of computer models was developed. It gives guidelines for the design and setup of participatory arrangements in conjunction with computer models. Besides procedural recommendations lessons can be drawn concerning the kind of output the tools should provide and the early involvement of users is modelling and software development. (C) 2001 Elsevier Science Ltd. All rights reserved. 5492,2001,2,4,Thermolysis of fluoropolymers as a potential source of halogenated organic acids in the environment,Following the introduction of hydrochlorofluorocarbon (HCFCs) and hydrofluorocarbon (HFCs) gases as replacements for the ozone-destroying chlorofluorocarbons (CFCs)| it has been discovered that HCFCs/HFCs can degrade in the atmosphere to produce trifluoroacetic acid(1)| a compound with no known loss mechanisms in the environment(2|3)| and higher concentrations in natural waters(4) have been shown to be mildly phytotoxic(5). Present environmental levels of trifluooracetic acid are not accounted by HCFC/HFC degradation alone(8-10). Here we report that thermolysis of fluorinated polymers| such as the commercial polymers Teflon and Kel-F| can also produce trifluoroacetate and the similar compound chlorodifluoroacetate. This can occur either directly| or indirectly via products that are known to degrade to these haloacetates in the atmosphere(11). The environmental significance of these findings is confirmed by modelling| which indicates that the thermolysis of fluoropolymers in industrial and consumer high-temperature applications (ovens| nonstick cooking utensils and combustion engines) is likely to be a significant source of trifluoroacetate in urban rain water (similar to 25 ng l(-1)| as estimated for Toronto). Thermolysis also leads to longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. Some of these products have recently been linked with possible adverse health(6) and environmental impacts and are being phased out of the US market(7). Furthermore| we detected CFCs and fluorocarbons- groups that can destroy ozone and act as greenhouse gases| respectively-among the other thermal degradation products| suggesting that continued use of fluoropolymers may also exacerbate stratospheric ozone-depletion and global warming. 2976,2001,5,4,Time-series analysis of delta C-13 from tree rings. I. Time trends and autocorrelation,Univariate time-series analyses were conducted on stable carbon isotope ratios obtained from tree-ring cellulose. We looked for the presence and structure of autocorrelation. Significant autocorrelation violates the statistical independence assumption and biases hypothesis tests. Its presence would indicate the existence of lagged physiological effects that persist for longer than the current year. We analyzed data from 28 trees (60-85 years old; mean = 73 years) of western white pine (Pinus monticola Dougl.)| ponderosa pine (Pinus ponderosa Laws.)| and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca) growing in northern Idaho. Material was obtained by the stem analysis method from rings laid down in the upper portion of the crown throughout each tree's life. The sampling protocol minimized variation caused by changing light regimes within each tree. Autoregressive moving average (ARMA) models were used to describe the autocorrelation structure over time. Three time series were analyzed for each tree: the stable carbon isotope ratio (delta C-13); discrimination (Delta); and the difference between ambient and internal CO2 concentrations (c(a) - c(i)). The effect of converting from ring cellulose to whole-leaf tissue did not affect the analysis because it was almost completely removed by the detrending that precedes time-series analysis. A simple linear or quadratic model adequately described the time trend. The residuals from the trend had a constant mean and variance| thus ensuring stationarity| a requirement for autocorrelation analysis. The trend over time for c(a) - c(i) was particularly strong (R-2 = 0.290.84). Autoregressive moving average analyses of the residuals from these trends indicated that two-thirds of the individual tree series contained significant autocorrelation| whereas the remaining third were random (white noise) over time. We were unable to distinguish between individuals with and without significant autocorrelation beforehand. Significant ARMA models were all of low order| with either first- or second-order (i.e.| lagged 1 or 2 years| respectively) models performing well. A simple autoregressive (AR(1))| model was the most common. The most useful generalization was that the same ARMA model holds for each of the three series (delta C-13| Delta| c(a) - c(i)) for an individual tree| if the time trend has been properly removed for each series. The mean series for the two pine species were described by first-order ARMA models (1-year lags)| whereas the Douglas-fir mean series were described by second-order models (2-year lags) with negligible first-order effects. Apparently| the process of constructing a mean time series for a species preserves an underlying signal related to delta C-13 while canceling some of the random individual tree variation. Furthermore| the best model for the overall mean series (e.g.| for a species) cannot be inferred from a consensus of the individual tree model forms| nor can its parameters be estimated reliably from the mean of the individual tree parameters. Because two-thirds of the individual tree time series contained significant autocorrelation| the normal assumption of a random structure over time is unwarranted| even after accounting for the time trend. The residuals of an appropriate ARMA model satisfy the independence assumption| and can be used to make hypothesis tests. 5386,2001,2,4,Timing of squid migration reflects North Atlantic climate variability,The environmental and biotic conditions affecting fisheries for cephalopods are only partially understood. A problem central to this is how climate change may influence population movements by altering the availability of thermal resources. In this study we investigate the links between climate and sea-temperature changes and squid arrival time off southwestern England over a 20-year period. We show that veined squid (Loligo forbesi) migrate eastwards in the English Channel earlier when water in the preceding months is warmer| and that higher temperatures and early arrival correspond with warm (positive) phases of the North Atlantic oscillation (NAO). The timing of squid peak abundance advanced by 120150 days in the warmest years ('early' years) compared with the coldest ('late' years). Furthermore| sea-bottom temperature was closely linked to the extent of squid movement. Temperature increases over the five months prior to and during the month of peak squid abundance did not differ between early and late years| indicating squid responded to temperature changes independently of time of year. We conclude that the temporal variation in peak abundance of squid seen off Plymouth represents temperature-dependent movement| which is in turn mediated by climatic changes associated with the NAO. Such climate-mediated movement may be a widespread characteristic of cephalopod populations worldwide| and may have implications for future fisheries management because global warming may alter both the timing and location of peak population abundance. 5447,2001,2,4,Tolerance to high temperatures and potential impact of sea warming on reef fishes of Gorgona Island (tropical eastern Pacific),Knowledge of upper thermal-tolerance limits of marine organisms in the tropical eastern Pacific (TEP) is important because of the influence of phenomena such as El Nino and global warming| which increase sea temperature. Laboratory experiments were conducted to determine the critical thermal maximum (CTM) of reef fishes from the TEP. In 15 reef fishes of Gorgona Island (TEP) the CTM was between 34.7 degreesC and 40.8 degreesC. None of these CTMs was exceeded by sea temperature in the TEP during any of the strongest El Nino events in this century (32 degreesC during El Nino 1982-1983 and 1997-1998). which indicates that all species studied here may tolerate El Nino maximum temperatures. In addition| the CTM of the least-tolerant species was 8 degreesC above the current mean sea temperature in a wide range of latitudes in the TER This suggests that fishes live far from their upper thermal tolerance limits and that the current global-warming trend is still unlikely to be dangerous for these species. If sea temperature continues to increase at the current rate| in about a century sea temperature could exceed the thermal tolerance of some reef fishes and threaten them with extinction. Such risk. however| might occur sooner if the sea temperature during El Nino also increased in step with the global warming| but also because other processes involved in maintaining population| such as reproduction| can be affected at lower temperatures. The possible ability| of reef fishes to adapt to increases in sea temperature is discussed. 2954,2001,3,3,Towards a private-public synergy in financing climate change mitigation projects,Funding for greenhouse gas mitigation projects in developing countries is crucial for addressing the global climate change problem. By examining current climate change-related financial mechanisms and their limitations| this paper indicates that their roles are limited in affecting developing countries' future emissions| and argues for the necessity of stronger private sector engagement in financing mitigation projects. In this regard| the clean development mechanism (CDM)| one of the flexibility mechanisms incorporated into the Kyoto Protocol| could offer great potential in helping mobilize foreign direct investment towards climate mitigation| by providing commercial incentives for the private sector to invest in mitigation projects and internalizing externalities associated with mitigation projects. However| due to additional risks and barriers involved in CDM projects| we believe that appropriate public-private linkage would be necessary in order to bring the CDM into full play. To this end| we suggest that public funds could be used to complement private investment via the CDM| thus enhancing market functions of such an investment. Moreover| in so doing| we think that it would be necessary to examine a host of factors| such as risk sharing| private sector investment behaviour| types of technologies to be transferred| and co-ordination with the commonly practiced trade and investment rules. (C) 2001 Elsevier Science Ltd. All rights reserved. 5534,2001,3,4,Trading carbon tradable offsets under Kyoto's clean development mechanism: the economic advantages to buyers and sellers of using call options,Under the Kyoto Protocol's clean development mechanism| developed countries may purchase or trade for emission reduction units or greenhouse gas (GHG) offsets originating either from excess quota allocations or from developing countries' projects. Selling emission reduction units before a market has actually developed presents pricing problems for both sellers and buyers. In the case of sequestered carbon and in the example of a Costa Rican project| it may be economically beneficial to both buyer and seller alike for the buyer to purchase the right| but not the obligation| to purchase a carbon tradable offset (CTO). It is shown by valuing purchases and sales of CTO options that advantages from such an instrument are possible to both seller and buyer at least until a true market in GHG offset trading develops. (C) 2001 Elsevier Science B.V. All rights reserved. 2989,2001,4,3,Transient behaviour of tropospheric ozone precursors in a global 3-D CTM and their indirect greenhouse effects,The global three-dimensional Lagrangian chemistry-transport model STOCHEM has been used to follow the changes in the tropospheric distributions of the two major radiatively-active trace gases| methane and tropospheric ozone| following the emission of pulses of the short-lived tropospheric ozone precursor species| methane| carbon monoxide| NO(x) and hydrogen. The radiative impacts of NO(x) emissions were dependent on the location chosen for the emission pulse| whether at the surface or in the upper troposphere or whether in the northern or southern hemispheres. Global warming potentials were derived for each of the short-lived tropospheric ozone precursor species by integrating the methane and tropospheric ozone responses over a 100 year time horizon. Indirect radiative forcing due to methane and tropospheric ozone changes appear to be significant for all of the tropospheric ozone precursor species studied. Whereas the radiative forcing from methane changes is likely to be dominated by methane emissions| that from tropospheric ozone changes is controlled by all the tropospheric ozone precursor gases| particularly NO(x) emissions. The indirect radiative forcing impacts of tropospheric ozone changes may be large enough such that ozone precursors should be considered in the basket of trace gases through which policy-makers aim to combat global climate change. 5655,2001,4,3,Trend in atmospheric angular momentum in a transient climate change simulation with greenhouse gas and aerosol forcing,The authors investigate the change of atmospheric angular momentum (AAM) in long| transient| coupled atmosphere-ocean model simulations with increasing atmospheric greenhouse gas concentration and sulfate aerosol loading. A significant increase of global AAM| on the order of 4 x 10(25) kg m(2) s(-1) for 3 x CO2-1 x CO2| was simulated by the Canadian Centre for Climate Modelling and Analysis (CCCma) coupled model. The increase was mainly contributed by the relative component of total AAM in the form of an acceleration of zonal mean zonal wind in the tropical-subtropical upper troposphere. Thus| under strong global warming| a super-rotational state emerged in the tropical upper troposphere. The trend in zonal mean zonal wind in the meridional plane was characterized by 1) a tropical-subtropical pattern with two maxima near 30 degrees in the upper troposphere| and 2) a tripole pattern in the Southern Hemisphere extending through the entire troposphere and having a positive maximum at 60 degreesS. The implication of the projected increase of global AAM for future changes of the length of day is discussed. The CCCma coupled global warming simulation| like many previous studies| shows a significant increase of tropical SST and includes a zonally asymmetric component that resembles El Nino SST anomalies. In the CCCma transient simulations| even though the tropical SST and global AAM both increased nonlinearly with time| the ratio of their time increments Delta AAM/Delta SST remained approximately constant at about 0.9 x 10(25) kg m(2) s(-1) (degreesC)(-1). This number is close to its counterpart for the observed global AAM response to El Nino. It is suggested that this ratio may be useful as an index for intercomparisons of different coupled model simulations. 5659,2001,2,3,Trends in Northern Hemisphere surface cyclone frequency and intensity,One of the hypothesized effects of global warming from increasing concentrations of greenhouse gases is a change in the frequency and/or intensity of extratropical cyclones. In this study| winter frequencies and intensities of extratropical cyclones in the Northern Hemisphere for the period 1959-97 are examined to determine if identifiable trends are occurring. Results indicate a statistically significant decrease in midlatitude cyclone frequency and a significant increase in high-latitude cyclone frequency. In addition| storm intensity has increased in both the high and midlatitudes. The changes in storm frequency correlate with changes in winter Northern Hemisphere temperature and support hypotheses that global warming may result in a northward shift of storm tracks in the Northern Hemisphere. 5537,2001,2,2,Trends in upper-tropospheric humidity,Water vapor is the most radiatively active greenhouse gas| and the process of water-vapor feedback may significantly; amplify global warming induced by anthropogenic greenhouse gasses. Satellite radiance observations from the past 20 years| which are sensitive to the mater vapor and temperature of the upper troposphere| provide the first global observations of trends in upper-tropospheric humidity. These decadal trends are strongly positive in the deep tropics| negative in the Southern Hemisphere subtropics and midlatitudes| and of mixed sign in the Northern Hemisphere subtropics and midlatitudes. The trends are shown to be consistent with atmospheric circulation changes observed in the past 20 years| including a tendency toward more EI Nino-Southern Oscillation warm events and changes in transient eddy activity in the subtropics. 5387,2001,4,3,Trends of measured climate forcing agents,The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/m(2) per century. This growth rate has since declined to approximate to3 W/m(2) per century| largely because of cooperative international actions. We argue that trends can be reduced to the level needed for the moderate "alternative" climate scenario (approximate to2 W/m(2) per century for the next 50 years) by means of concerted actions that have other benefits| but the forcing reductions are not automatic "co-benefits" of actions that slow CO2 emissions. Current trends of climate forcings by aerosols remain very uncertain. Nevertheless| practical constraints on changes in emission levels suggest that global warming at a rate +0.15 +/- 0.05 degreesC per decade will occur over the next several decades. 2979,2001,5,4,U-Th dating of carbonate platform and slope sediments,Absolute chronology of marine sediment beyond the C-14 age range provides a test for models of climate change and has many other applications. U-Th techniques have been used for such chronology by dating corals| but extending these techniques to marine sediment is complicated by the presence of significant initial Th-230-both in detrital material and scavenged from seawater. In this study| we investigate four methods of solving the initial Th-230 problem for a particular type of marine sediment-the aragonite-rich sediments of carbonate platforms and slopes. Bulk sediment U-Th analyses can be corrected for initial Th to yield ages with approximate to2 to 3 kyr precision for highstand periods when sediment aragonite contents are particularly high. Uncertainty on the corrections causes inadequate precision for sediment from other periods| however. Removal of scavenged Th before analysis would enable a dramatic increase in this precision but has not proved successful despite a range of chemical leach approaches. Using heavy liquids to separate the various carbonate minerals found in Bahamas sediment enables an isochron approach to correct for initial Th| but the presence of initial Th from two sources requires correction or removal of one source of initial Th before the other is deconvolved by the isochron. Quantitative removal of detrital material before isochron analysis proves a successful approach. Such isochron data demonstrate that| although sediment remains closed to U-Th on a centimetre scale| nuclides are moved from grain to grain by alpha -recoil. Such intergrain exchange is expected to be observed in all sediments containing mineral grains with different U concentrations. Measured U-234/U-238 allows the recoil movement to be corrected and results in isochron ages with precision sometimes as low as 3 kyr. The accuracy of this approach has been proved by dating samples within the 14C age range. Sediments spanning the penultimate deglaciation have also been dated. After a small correction for bioturbation| the age for this event is found to be 135.2 +/- 3.5 ka. TWs date is approximate to8 kyr before the peak in northern hemisphere insolation and suggests that deglaciation is initiated by a mechanism in the southern hemisphere or tropics. This isochron approach shows considerable promise for dating of sediments older than this event| which will provide further information about the timing and mechanisms of global climate change. Copyright (C) 2001 Elsevier Science Ltd. 2963,2001,3,3,Uncertainty in estimating and mitigating industrial related GHG emissions,Global climate change has been one of the challenging environmental concerns facing policy makers in the past decade. The characterization of the wide range of greenhouse gas emissions sources and sinks as well as their behavior in the atmosphere remains an on-going activity in many countries. Lebanon| being a signatory to the Framework Convention on Climate Change| is required to submit and regularly update a national inventory of greenhouse gas emissions sources and removals. Accordingly| an inventory of greenhouse gases from various sectors was conducted following the guidelines set by the United Nations Intergovernmental Panel on Climate Change (IPCC). The inventory indicated that the industrial sector contributes about 29 percent to the total greenhouse gas emissions divided between industrial processes and energy requirements at 12 and 17 percent| respectively. This paper describes major mitigation scenarios to reduce emissions from this sector based on associated technical| economic| environmental| and social characteristics. Economic ranking of these scenarios was conducted and uncertainty in emission factors used in the estimation process was emphasized. For this purpose| theoretical and experimental emission factors were used as alternatives to default factors recommended by the IPCC and the significance of resulting deviations in emission estimation is presented. (C) 2001 Elsevier Science Ltd. All rights reserved. 5405,2001,5,4,Uncorking the bottle: What triggered the Paleocene/Eocene thermal maximum methane release?,The Paleocene/Eocene thermal maximum (PETM) was a time of rapid global warming in both marine and continental realms that has been attributed to a massive methane (CH4) release from marine gas hydrate reservoirs. Previously proposed mechanisms for this methane release rely on a change in deepwater source region(s) to increase water temperatures rapidly enough to trigger the massive thermal dissociation of gas hydrate reservoirs beneath the seafloor. To establish constraints on thermal dissociation| we model heat flow through the sediment column and show the effect of the temperature change on the gas hydrate stability zone through time. In addition| we provide seismic evidence tied to borehole data for methane release along portions of the U.S. continental slope; the release sites are proximal to a buried Mesozoic reef front. Our model results| release site locations| published isotopic records| and ocean circulation models neither confirm nor refute thermal dissociation as the trigger for the PETM methane release. In the absence of definitive evidence to confirm thermal dissociation| we investigate an alternative hypothesis in which continental slope failure resulted in a catastrophic methane release. Seismic and isotopic evidence indicates that Antarctic source deepwater circulation and seafloor erosion caused slope retreat along the western margins of the North Atlantic in the late Paleocene. Continued erosion or seismic activity along the oversteepened continental margin may have allowed methane to escape from gas reservoirs trapped between the frozen hydrate-bearing sediments and the underlying buried Mesozoic reef front| precipitating the Paleocene/Eocene boundary methane release. An important implication of this scenario is that the methane release caused (rather than resulted from) the transient temperature increase of the PETM. Neither thermal dissociation nor mechanical disruption of sediments can be identified unequivocally as the triggering mechanism for methane release with existing data. Further documentation with high-resolution benthic foraminiferal isotopic records and with seismic profiles tied to borehole data is needed to clarify whether erosion| thermal dissociation| or a combination of these two was the triggering mechanism for the PETM methane 5438,2001,4,2,Understanding and managing the risks to health and environment from global atmospheric change: A synthesis,The global atmosphere is changing. Anthropogenic activities are increasing the concentrations of greenhouse gases and releasing synthetic compounds that deplete stratospheric ozone and increase UV-B radiation. Changes of temperature in the Northern Hemisphere during the past century strongly suggest that we are now in a period of rapid global warming relative to the past millennium. Increased concentrations of greenhouse gases are absorbing outgoing infrared radiation in the lower atmosphere| warming the troposphere and cooling the lower stratosphere. Research is beginning to indicate that losses of stratospheric ozone and increases of greenhouse gases are interdependent. Increased greenhouse gases have been implicated in the observed strengthening of stratospheric wind vortices around both poles| in turn setting the stage for further depletion of ozone and increases in UV-B radiation. Although the uncertainties are still large enough to make it difficult to assess health and ecological risks| decisions must be made. Research on indicators of risks to human health and the environment can help reduce the uncertainties in these risks and shorten the time between recognizing the risks of atmospheric change and taking concrete mitigative and adaptive actions. 5635,2001,3,4,United States experience with gasoline additives,History| benefits and problems associated with gasoline additives in the United States were reviewed. To reduce air toxics and ozone in highly air-polluted areas of the country| oxygenates will continue to be added to gasoline until an alternative is sought and approved by the Congress of the United States. In near future| the use of methyl tert butyl ether (MTBE) will be reduced from its present magnitude and could be replaced by ethanol or other oxygenates that are less harmful to the environment. With rising oil prices| global warming and other environmental issues in the horizon| it is very likely that in the future| hydrogen will substitute gasoline to power electrically driven motors in automobiles. Nevertheless| hydrogen has to be extracted from a readily available source such as gasoline. If gasoline is going to be used as a source of hydrogen| it has to be reformulated from its present form and there will be no need for any additives. (C) 2000 Elsevier Science Ltd. All rights reserved. 5454,2001,4,3,Updated radiative forcing estimates of 65 halocarbons and nonmethane hydrocarbons,The direct radiative forcing of 65 chlorofluorocarbons| hydrochlorofluorocarbons| hydrofluorocarbons| hydrofluoroethers| halons| iodoalkanes| chloroalkanes| bromoalkanes| perfluorocarbons and nonmethane hydrocarbons has been evaluated using a consistent set of infrared absorption cross sections. For the radiative transfer models| both line-by-line and random band model approaches were employed for each gas. The line-by-line model was first validated against measurements taken by the Airborne Research Interferometer Evaluation System (ARIES) of the U.K. Meteorological Office; the computed spectrally integrated radiance of agreed to within 2% with experimental measurements. Three model atmospheres| derived from a three-dimensional climatology| were used in the radiative forcing calculations to more accurately represent hemispheric differences in water vapor| ozone concentrations| and cloud cover. Instantaneous| clear-sky radiative forcing values calculated by the line-by-line and band models were in close agreement. The band model values were subsequently modified to ensure exact agreement with the line-by-line model values. Calibrated band model radiative forcing values| for atmospheric profiles with clouds and using stratospheric adjustment| are reported and compared with previous literature values. Fourteen of the 65. molecules have forcings that differ by more than 15% from those in the World Meteorological Organization [1999] compilation. Eleven of the molecules have not been reported previously.. The 65-molecule data set reported here is the most comprehensive and consistent database yet available to evaluate the relative impact of halocarbons and hydrocarbons on climate change. 5581,2001,5,4,US Gulf Coast vegetation dynamics during the latest Palaeocene,Pollen and spore floras from the Bear Creek section in western Alabama (US Gulf Coast) record vegetation events from the lower to middle Tuscahoma Formation (late Palaeocene mid NP9). Sporomorphs are abundant and well preserved in these sediments and are used as a proxy to record vegetation change over time. We present results from both palynofloral and clay mineral analyses in the interval approximately 0.4-0.1 my before the Paleocene/Eocene thermal maximum (PETM); a period of transient and intense global warming that had a profound effect on animal and plant groups in high latitudes. An important factor that has a significant bearing on our understanding of turnover across the PETM is that of climate/environmental stability prior to the PETM in terrestrial ecosystems. Palynological analysis with a between sample resolution of <10 ky suggests that the vegetation type characterising the US Gulf Coastal plains was highly stable with no significant changes in composition and diversity that can be successfully correlated with orbital oscillations. Our results indicate considerable stability of the vegetation type on time-scales of 10(4)-10(5) yr. Clay mineral suites show the dominance of smectite and illite throughout the studied section with minor fluctuations in the abundance of kaolinite (ranging from 2 to 10%) that indicates a high seasonality of precipitation throughout our studied section. The exact stratigraphic position of the PETM is unknown on the US Gulf Coast but data from existing publications suggests there is little change in the vegetation type across the Palaeocene/Eocene boundary with no major immigration or turnover events. Dinocysts art: restricted in both diversity and occurrence but Apectodinium homomorphum is present withCulicoides imicola| a vector of bluetongue virus and African horse sickness virus| is principally Afro-Asian in distribution| but has recently been found in parts of Europe. A logistic regression model based on climate data (temperature| saturation deficit| rainfall and altitude) and the published distribution of C. imicola in Iberia was developed and then applied to other countries in Europe| to identify locations where C. imicola could become established. The model identified three temperature variables as significant determinants of the distribution of C. imicola in Iberia (minimum of the monthly minimum temperatures| maximum of the monthly maximum temperatures and number of months per year with a mean temperature greater than or equal to 12.5 degreesC). The model indicated that under current conditions| the distribution of C. imicola in Spain| Greece and Italy could be extended and the vector could potentially invade parts of Albania| Yugoslavia| Bosnia and Croatia. To simulate the effect of global warming| temperature values in the model were increased by 2 degreesC. Under these conditions| the potential spread of C. imicola in Europe would be even more extensive.
5601,2001,4,4,Validation of ECMWF (re)analysis surface climate data| 1979-1998| for Greenland and implications for mass balance modelling of the Ice Sheet,Climate (re)analysis products are potentially valuable tools| when properly verified| for helping to constrain the surface mass balance of the Greenland Ice Sheet (GIS). Monthly surface fields from European Centre for Medium-Range Weather Forecasts (ECMWF) operational- and re-analyses spanning 1979-1998 were validated using in situ data (surface air pressure and temperature| precipitation| cloud cover| short-/all-wave radiation| and wind speed/direction). These validation data are from coastal or near-coastal Danish Meteorological Institute (DMI) synoptic stations| inland Greenland Climate Network (CC-Net) and University of Wisconsin Automatic Weather Stations (AWSs)| and two energy balance stations near the southern ice margin. The ECMWF analyses closely reproduce the seasonal patterns and interannual variations of much of the in situ data. Differences in the mean values of surface air pressure and temperature can mainly be ascribed to orography errors in the analyses' schemes| compared with the latest available accurate digital elevation model. Much of the GIS margin as modelled by ECMWF was too cold| on average by 4 degreesC| and ECMWF precipitation averaged some 136% of the DMI station values. The misrepresentation of the (relatively) steep ice-sheet margin| which tends to be broadened and systematically over-elevated by several hundred metres| orographically reduced temperature and enhanced precipitation there in the ECMWF models. The cloud-cover comparison revealed not dissimilar annual mean cloud covers (ECMWF -8%) but the ECMWF analyses had too little cloud and were too 'sunny' during the critical summer melt season. ECMWF-modelled surface albedo in summer was similar to 11% lower than CC-Net values| which was mainly responsible for the disagreement of modelled surface short-wave radiation fluxes with observations. Model albedo and cloud errors need to be rectified if the analyses are to be used effectively to drive energy balance models of Greenland snowmelt. ECMWF wind speed averaged 66% (62%) of the DMI station (AWS) values. The validation results provide useful insights into how one can best improve the ECMWF Greenland climate data for use in glaciological and climatological studies. Copyright (C) 2001 Royal Meteorological Society. 3004,2001,5,4,Variations in chemical compositions of the eolian dust in Chinese Loess Plateau over the past 2.5 Ma and chemical weathering in the Asian inland,Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (Al) phase of the loess-paleosol sequence from Luochuan| Shaanxi Province| China. Results show that the chemical composition of Al phase of loess and paleosols is distinctive to the average composition of upper continental crust (UCC)| characterized by depletion of mobile elements Na| Ca and Sr. The distribution pattern of elements in Al phase reveals that initial dust| derived from a vast area of Asian inland| has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters (such as CIA values| Na/K| Rb/Sr and Sr-87/Sr-88 ratios) display a regular variation and evolution| reflecting that the chemical weathering in the source region of loess deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change. 5523,2001,2,4,Vegetation succession and carbon sequestration in a coastal wetland in northwest Florida: Evidence from carbon isotopes,Measurements of stable carbon isotopic ratios as well as carbon (C)| nitrogen (N)| and phosphorus (P) contents in soils and plants were made along a chronovegetation sequence stretching from high marsh to low marsh in a coastal wetland in northwest Florida. The wetland is dominated by Juncus roemerianus| which is a C3 plant and has an average delta C-13 of -27 parts per thousand. Lesser amounts of other species| including C4 plants| are also present in the area. The delta C-13 values of soil organic matter from low and middle marshes range from -24 to -27 parts per thousand| which are consistent with the current plant community. However| the delta C-13 values of soil organic matter from high marsh show significant variations| from -23 parts per thousand in the surface soil to -17 parts per thousand at depth. This large C isotopic variation within soil profiles indicates a shift in local vegetation| from a C4-dominated community to the current C3 plant-dominated marsh| as a result of landward expansion of the wetland due to sea level rise. Radiocarbon dates on soil organic matter indicate that this ecological change occurred in the past hundred years or so as a result of sea level rise presumably due to global warming. Soil organic carbon inventory was similar to 29 +/- 3.6 kg m(-2) in low marsh (the oldest part of the wetland)| 15 +/- 3.6 kg m(-2) in middle marsh| and 13 +/- 6.0 kg m(-2) in high marsh (the youngest and most inland part of the wetland). N and P inventories are also higher in low marsh than in high marsh and seem to correlate directly with aboveground productivity in the marshes. The much higher C storage in low marsh than in high marsh indicates that carbon sequestration increased significantly as coastal wetland evolves from high marsh (initial stage) to low marsh (steady state). This has important implications to the global C cycle. As sea level rises owing to global warming| coastal wetlands are expected to expand landward in many areas where topography is gentle| which would provide a significant sink for atmospheric carbon dioxide. 5530,2001,3,4,Verification: The gorilla in the struggle to slow global warming,Last November's "make or break" summit to settle the fine print for the Kyoto Protocol ran aground on the shoals of a strange and misdirected dispute between the U.S. and the European Union. The U.S. and several other countries sough liberal rules for the international trading of emission permits as well as generous credits for "sinks" such as forests and agricultural soils that absorb carbon dioxide from the atmosphere. Those provisions would make it easier to comply with the Kyoto Protocol's emission targets. European governments sough to plug these "loopholes" that would let countries evade serious action through clever accounting tricks and by purchasing credits overseas. Despite around-the-clock back room dealing| the diplomats never settled all their differences and the summit ended in bitter recriminations across the Atlantic and within Europe. Efforts to clean up the diplomatic mess failed| and now the Kyoto Protocol is in even more serious trouble as the U.S. has announced it will not ratify the pact. A growing chorus is now thinking about life "beyond Kyoto" - to a successor agreement (Victor 2001). The same debates about forest and soil carbon sinks will arise. How should they be settled? What can the forestry community do to help?
5436,2001,5,3,Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs,Climate models with increased levels of carbon dioxide predict that global warming causes heating in the tropics| but investigations of ancient climates based on palaeodata have generally indicated cool tropical temperatures during supposed greenhouse episodes. For example| in the Late Cretaceous and Eocene epochs there is abundant geological evidence for warm| mostly ice-free poles| but tropical sea surface temperatures are generally estimated to be only 15-23 degreesC| based on oxygen isotope palaeothermometry of surface-dwelling planktonic foraminifer shells. Here we question the validity of most such data on the grounds of poor preservation and diagenetic alteration. We present new data from exceptionally well preserved foraminifer shells extracted from impermeable clay-rich sediments| which indicate that for the intervals studied| tropical sea surface temperatures were at least 28-32 degreesC. These warm temperatures are more in line with our understanding of the geographical distributions of temperature-sensitive fossil organisms and the results of climate models with increased CO2 levels. 5590,2001,2,4,Warmer springs disrupt the synchrony of oak and winter moth phenology,Spring temperatures have increased over the past 25 years| to which a wide variety of organisms have responded. The outstanding question is whether these responses match the temperature-induced shift of the selection pressures acting on these organisms. Organisms have evolved response mechanisms that are only adaptive given the existing| relationship between the cues organisms use and the selection pressures acting on them. Global warming may disrupt ecosystem interactions because it alters these relationships and micro-evolution may be slow in tracking these changes. In particular| such shifts have serious consequences for ecosystem functioning for the tight multitrophic interactions involved in the timing of reproduction and growth. We determined the response of winter moth (Operophtera brumata) egg hatching and oak (Quercus robur) bud burst to temperature| a system with strong selection on synchronization. We show that there has been poor synchrony in recent warm springs| which is due to an increase in spring temperatures without a decrease in the incidence of freezing spells in winter. This is a clear warning that such changes in temperature patterns may affect ecosystem interactions more strongly than changes in mean temperature. 5464,2001,2,4,Warming and structural changes in the East(Japan) Sea: A clue to future changes in global oceans?,The East (Japan) Sea has been in a warming trend during the last more than 40 years: a 0.1 - 0.5 degree of warming in the upper 1000 meters. The warming is accompanied by the deepening of the oxygen minimum layer by more than 1000 meters. The analysis of chemical tracers such as dissolved oxygen and CFCs clearly implies that the warming is associated with changes in deep water structures in the area| resulted from a replacement of the past bottom-water formation with an intermediate water formation in recent time. This shift has a remarkable resemblance to that anticipated to the ocean conveyor-belt system in coming century associated with recent global warming. In considering a rapid turn-over time of time scale less than 100 years| the East Sea may serve as a natural laboratory for global changes in the future. 5637,2001,2,4,Warming asymmetry in climate change simulations,Climate change simulations made with coupled global climate models typically show a marked hemispheric asymmetry with more warming in the northern high latitudes than in the south. This asymmetry is ascribed to heat uptake by the ocean at high southern latitudes. A recent version of the CCCma climate model exhibits a much more symmetric warming| compared to an earlier version| and agrees somewhat better with observed 20th century trends| This is associated with an improved parameterization of ocean mixing which results in a decrease in heat penetration into the Southern Ocean| in accord with earlier ocean-only and simple coupled model investigations. The global average warming and the net penetration of heat into the global ocean (and hence its thermal expansion) are essentially unchanged. Observed trends in sea-ice extent over the past two decades exhibit hemispheric asymmetry with a statistically significant decrease in northern but not in southern ice cover. Both model versions are consistent with these observations implying that observed ice extent is not yet an indicator of asymmetry in future global warming. Taken together| these results suggest that southern hemisphere climate warming at a rate comparable to that in the northern hemisphere should be considered a realistic possibility. 5505,2001,2,4,Water temperature and phytophenology indicate the earlier onset of oviposition in Eurasian Dipper (Cinclus cinclus) from the Swiss Lowlands,Initiation of reproduction was investigated in Eurasian Dipper (Cinclus cinclus) along riparian habitat of tributaries flowing into lower Lake Zurich (Switzerland). Total length of these drainages is 40 km and Dippers nested from 410 - 680 in asl. From 1992 to 2000 about 46 pairs per year had 552 successful broods with nestlings of at least 8 to 12 days of age. Meterological data (i. e.| air temperature| days with rain| amount of rainfall| amount of sunshine) and water temperature in a study area river were obtained from government weather stations. Phytophenological data| i.e. full flowering of Coltsfoot (Tussilago farfara)| Wood Anemone (Anemone nemorosa)| and Dandelion (Taraxacum officinale)| were also available from stations within the study area. Dippers initiated breeding in February or March of each year. with considerable variability among years. Earliest oviposition was 9 February 1995| and again 1997| while latest was 9 March 1992. The median date each year for appearance of the first 25 % of all broods was significantly correlated with February water temperatures (Spearman rank correlation. p < 0.001)| with February air temperatures (p < 0.002)| and with the flowering of two early phanerogams (Coltsfoot and Wood Anemone; p < 0.025)| but not Dandelion (p < 0.1). According to historical data| the initiation of reproduction for Dipper at Lake Zurich occurs now earlier in the year than it did in Britain| Germany| and Switzerland. This may be due either to global warming| or (more significantly) to an increase in water temperatures as a result of urbanisation. Warmer waters accelerate life cycles of aquatic arthropods and generate earlier emergences of insects that form the prey base of the Dipper. Since avian reproduction is cued by trophic resources| an earlier appearance of aquatic insects will concomitantly induce an earlier breeding season for the Dipper.
5651,2001,4,4,Why is the climate forcing of sulfate aerosols so uncertain?,Sulfate aerosol particles have strong scattering effect on the solar radiation transfer which results in increasing the planet albedo and| hence| tend to cool the earth-atmosphere system. Also| aerosols can act as the cloud condensation nuclei (CCN) which tend to increase the albedo of clouds and cool the global warming. The ARPEGE-Climat version 3 AGCM with FMR radiation scheme is used to estimate the direct and indirect radiative forcing of sulfate aerosols. For minimizing the uncertainties in assessing this kind of cooling effect| all kinds of factors are analyzed which have been mixed in the assessment process and may lead to the different results of the radiative forcing of aerosols| It is noticed that one of the uncertainties to assess the climate forcing of aerosols by GCM results from the different definition of radiative forcing that was used. In order to clarify this vague idea| the off-line case for considering no feedbacks and on-line case for including all the feedbacks have been used for assessment. The direct forcing of sulfate aerosols in off-line case is -0.57 W/m(2) and -0.38 W/m(2) for the clear sky and all sky respectively. The value of on-line case appears to be a little larger than that in off-line case chiefly due to the feedback of clouds. The indirect forcing of sulfate aerosols in off-line case is -1.4 W/m(2) and -1.0 W/m(2) in on-line case. The radiative forcing of sulfate aerosols has obvious regional characteristics| There is a larger negative radiative forcing over North America| Europe and East Asia. If the direct and indirect forcing are added together| it is enough to offset the positive radiative forcing induced by the greenhouse gases in these regions.
5685,2002,4,4,A comparison of variable solar total and ultraviolet irradiance outputs in the 20th century,[1] Differences in time-variation between total and ultraviolet solar irradiance could help in separating their influence on climate. We present the first models based on area measurements of magnetic plages from CaK spectroheliograms obtained between 1915-1999. Correlation of our time series of UV irradiance with global temperature| T| accounts for only 20% of the global temperature variance during the 20th century. Correlation of our total irradiance time series with T accounts statistically for 80% of the variance in global temperature over that period| although the irradiance variation amplitude is insufficient to influence global warming in present-day climate models. This interesting difference has been obscured in past modelling by additional components introduced to represent secular variations| which are no longer supported by current observational evidence. Future irradiance models emphasizing the more securely-based contributions of photospheric magnetic structures seem to provide better prospects for improved physical understanding of sun-climate links. 5905,2002,2,4,A computerized tank system for studying the effect of temperature on calcification of reef organisms,Mediated by algal symbionts| calcification in reef building corals is one of the important processes| which enable coral's growth. In the present study| we used a buoyant weighing technique to study calcification of two coralline species. Stylophora pistillata and the hydrocoral Millepora dichotoma. The colonies were grown in a tank system| in which light| nutrition and water motion were kept constant and temperature was elevated by means of a computerized controlled apparatus. An almost constant rate of calcification was observed in the two species at 22-28 degreesC. Elevation of the temperature above this range to 29-31 degreesC caused a slow down in calcification in both species. A grater number of S. pistillata colonies became bleached at temperatures of greater than or equal to 29 degreesC| whereas M. dichotoma colonies suffered from bleaching only after three days at 31 degreesC. For both species| control groups. remained viable during the experimental period. The differences in responses to changes in temperature of the two species may be as a consequence of different adaptive mechanisms or to different susceptibilities of the corals to elevated temperatures| We have shown that elevating temperatures above annual maximal ranges have a significant effect on coral calcification. We also demonstrated that sessile calcified marine organisms having ecological and biomedical significance could be cultured and manipulated under laboratory conditions. (C) 2002 Elsevier Science B.V. All rights reserved. 5914,2002,2,4,A cytotaxonomic survey of Rodents from Niger: implications for systematics| biodiversity and biogeography,We here present an inventory of rodents from Niger| mainly based on cytotaxonomic data because of the presence of many groups providing sibling species. A total of 39 species are listed| one of which is a new chromosomal form (Taterillus sp.). Moreover| three other cytotypes already described but still not specifically attributed were found (Mastomys sp.| Acomys sp. and Tatera sp). New karyotypic data are presented for Gerbillus nancillus| Graphiurus cf. parvus| Massouteria mzabi| and Xerus erythropus. Once again| the efficiency of cytotaxonomy for small mammals inventories is enhanced. Specific distribution maps of poorly known species are thus completed. No clear gradients could be observed between what is currently defined as the West and the East African faunas. The distributions are mainly structured in a latitudinal manner. The Air massif appears as a continuous prolongation of the Sahelian area| rather than as a Sahelian refuge in the Sahara. Five biogeographical groups of species were distinguished: 1) a Sudanian group in the area receiving less than 700 turn rainfall| 2) a group of very widespread species largely overlapping the Sudanian (more than 700 turn rainfall) and the Sahelian areas| and sometimes including some Saharan localities| 3) a typical Saharan group| 4) some species infeoded to the mountainous Saharan area| and 5) few strictly commensal species. A global southward extension of several taxa confirms the desertification of the Sahel| as a result of both natural global warming and human activities. 2942,2002,4,4,A discussion of recent evidence for solar irradiance variability and climate,One of the over-arching questions| among others| to be addressed by studying Sun-Earth connections is: "Is the climate changing in a way we can understand and predict?" The Earth's climate is the result of a complex and incompletely understood system of external inputs and interacting parts. Climate change can occur over a range of time scales| may be driven by natural variability| including solar variability| and/or anthropogenic causes and may be identified through the study of a variety of measurable parameters. Global climate change in response to human influences is one of the pressing threats facing science today. However| many of the external factors that govern our climate| including solar variability| cannot be adequately determined from existing operational observations. Since the Sun is the fundamental source of energy that sustains life on Earth| establishing its radiation environment| controls its temperature and atmospheric composition| the accurate knowledge of the solar radiation received by the Earth and understanding of its variability are critical for environmental science and climate studies. In this paper we point out the necessity of a new strategy| i.e.| to study global solar properties| such as solar irradiance| solar shape| shape oscillations| and radius| to better understand the origin of solar-induced climate changes. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. 2863,2002,2,2,A first-order analysis of the climate change effect on flood frequencies in a subalpine watershed by means of a hydrological rainfall-runoff model,Scientific evidence indicates that a global climate change due to human activity is possible within a century. It is expected that doubling Of CO2 and increasing the amount of other greenhouse gases in the atmosphere would result in more severe weather| among other consequences. The purpose of the paper is to examine how flood frequencies and magnitudes in a midsize subalpine watershed on the eastern slopes of the Rocky Mountains in Alberta| Canada| would change under 2 X CO2 conditions. Given the poor spatial resolution of present general circulation models (GCM) and their uncertain performance at the regional scale| a first-order analysis is carried on| in which only rainfall intensity changes are considered to have the most significant impact on future floods. Estimates of storm rainfall increases are based on the literature survey| GCM projections for the study area| and transposition of southern climatic conditions. Two scenarios of likely most severe changes were selected: first| a 25% increase in the mean and standard deviation of Gumbel distribution of rainfall depth for storm durations from 6 to 48 h; second| a 50% increase in the standard deviation only. The HEC-1 watershed model and the soil conservation service runoff curve method for abstractions were used in Monte Carlo simulation. Comparison of Monte Carlo derived flood frequency curves for the two scenarios with the present day curve shows that scenario I is more critical in terms of flood flow increases than scenario 2. Under scenario 1| the mean annual flood on the study watershed would increase by almost 80% and the 100-year flood would increase by 41%. (C) 2002 Elsevier Science B.V. All rights reserved. 5932,2002,5,4,A late neoproterozoic eastern Laurentian superplume: Location| size| chemical composition| and environmental impact,A database consisting of 25 data-sets has been compiled that includes published chemical analyses of most known eastern North American occurrences of late Neoproterozoic (Vendian) flood basalt and dike swarms together with some new geochemical data. Four additional eastern North American basalt occurrences of probable early Paleozoic age were also examined. The Vendian occurrences comprise the Central Iapetus magmatic event of Eastern North America which extends from the Long Range dikes of Labrador and Newfoundland to the Catoctin flood basalts of Virginia and includes the Grenville dike swarm of Ontario and Quebec. The strike of the Vendian dike swarms converge near a major gravity and magnetic anomaly at Sutton Mountain| Quebec. The chemical composition of the Vendian basalts and diabase dikes plotted onto spider diagrams normalized to the composition of the silicate earth can be subdivided into a tight cluster of parallel lines displaying HFSE enrichment and a more diverse group that is less enriched. The tight grouping of the enriched cluster suggests a mutual genetic relationship consistent with mantle plume derivation based largely on chemical similarity to standard Ocean Island Basalt (OIB). However| detailed examination of this eastern Laurentian OIB related cluster (LOIB) reveals regional variations in chemical composition| particularly TiO2 and Zr| that can be contoured to delineate a narrow lens shape with peak concentrations centered close to the Sutton Mountain triple junction. The central portion of the LOIB is geochemically the same as superplume derived basalt. Radiometric evidence indicates that the LOIB superplume magmatic activity peaked at about 550 Ma. The less enriched group geochemically resembles some of Earth's larger continental flood basalts| such as the Columbia River basalt province| derived from a subcontinental lithospheric mantle source mixed with magma from a mantle plume source. Radiometric and paleomagnetic evidence indicates that this less enriched group is about 615 to 564 Ma and probably extruded out of rifts that preceded the break-up of Pannotia. This mid-Vendian magmatism is consistent with the early stages of deep mantle plume upwelling but may be genetically independent of the superplume magmatism that followed. The four early Paleozoic basalt suites examined are interpreted as post-LOIB| lapetan Ocean ridge basalt accreted onto eastern Laurentian or perhaps basalt extruded from transform faults that intersected the trailing edge of Laurentia. If LOIB magmatism was generated by a superplume head| there may be important environmental implications. The LOIB event may have been partially responsible for considerable mantle outgassing| particularly carbon dioxide and nutrients| global warming| and major increases in the growth rate and deposition of marine life that occurred during the early Cambrian. 5721,2002,2,4,A macro-scale and semi-distributed monthly water balance model to predict climate change impacts in China,Climatic change has great implications for hydrological cycle and water resources planning. In order to assess this impact. a macro-scale and semi-distributed monthly water balance model was proposed and developed to simulate and predict the hydrological processes. GIS techniques were used as a tool to analyze topography| river networks| land-use. human activities| vegetation and soil characteristics. The model parameters were linked to these basin characteristics by regression and optimization methods. A parameterization scheme was developed and the model parameters were estimated for each grid element. Based on the different GCM and RCM outputs| the sensitivities of hydrology and water resources for China to global warming were studied. The proposed models are capable of producing both the magnitude and timing of runoff and water resources conditions. The semi-dry regions| such as Liaohe| Haihe| Ruanhe and Huaihe River basins in north China| The runoffs of these basins are small or even zero during dry season (from Oct. to May) and are very sensitive to temperature increase and rainfall decrease. While in the basins of the humid south China like Yangtze River basin| the runoffs are perennial and the base flow normally occupies a large portion of the total runoff volume. These humid basins are less vulnerable to climate chance. Results of the study also indicated that runoff is more sensitive to variation in precipitation than to increase in temperature| Climate change challenges existing water resources management practices by additional uncertainty. Integrated water resources management will enhance the potential for adaptation to change. (C) 2002 Published by Elsevier Science B.V. 2876,2002,3,3,A modelling analysis of the potential for soil carbon sequestration under short rotation coppice willow bioenergy plantations,Rising atmospheric CO2 concentrations and their association with global climate change have led to several major international initiatives to reduce net CO2 emissions| including the promotion of bioenergy crops such as short rotation coppice (SRC) willow. Although the above-ground harvested bio-fuel is likely to be the major contributor to the CO2 mitigation potential of bioenergy crops| additional carbon may be sequestered through crop inputs into plantation soils. Here| we describe a process-based model specifically designed to evaluate the potential for soil carbon sequestration in SRC willow plantations in the UK. According to the model predictions| we conclude that the potential for soil carbon sequestration in these plantations is comparable to| or even greater than| that of naturally regenerating woodland. Our preliminary| site-specific model output suggests that soil carbon sequestration may constitute about 5% of the overall carbon mitigation benefit arising from SRC plantations. Sensitivity analyses identified the following factors as the principal controls on rates and amounts of soil carbon sequestration under SRC: carbon inputs (net primary production)| decomposition rates of the major soil carbon pools| initial soil carbon content (an inverse relationship with rates of soil carbon sequestration)| crop/plantation management| and depth of soil being influenced by the bioenergy crop. Our results suggest that carbon sequestration potential is greatest in soils whose carbon content has been depleted to relatively low levels due to agricultural land use practices such as annual deep ploughing of agricultural soils. 5950,2002,4,6,A multifractal point of view on climatological evolution,The global warming assumption has not yet been convincingly substantiated from hydrometerogical data analysis. In fact| as the atmosphere and the hydrosphere are highly non linear systems| one cannot expect a linear response to an increase of green house gas concentration because there exists various interactions and feedbacks at different scales between these systems and between their components. Before any prognosis about climate change it is rather indispensable to have a better knowledge of its natural variability. In any case| it will be extremely difficult or even fallacious to separate the anthropogenic and natural variability as it is likely that they strongly interact. To overcome such difficulties we argue that one has to keep as close as possible to the non linear physics of the involved phenomena. This is the objective of a multifractal analysis| which is both multiscale and multiintensity| of the available data. 2909,2002,3,4,A new decision sciences for complex systems,Models of complex systems can capture much useful information but can be difficult to apply to real-world decision-making because the type of information they contain is often inconsistent with that required for traditional decision analysis. New approaches| which use inductive reasoning over large ensembles of computational experiments| now make possible systematic comparison of alternative policy options using models of complex systems. This article describes Computer-Assisted Reasoning| an approach to decision-making under conditions of deep uncertainty that is ideally suited to applying complex systems to policy analysis. The article demonstrates the approach on the policy problem of global climate change| with a particular focus on the role of technology policies in a robust| adaptive strategy for greenhouse gas abatement. 5825,2002,2,4,A new joint probability appraisal of flood risk,Prior to the construction of the Cardiff Bay Barrage the risk of flooding of the Cardiff Bay waterfront was from inundation by surge tides. The barrage has substantially eliminated the probability of tidal flooding| and the residual flood risk now depends upon the ability of the inland bay to provide sufficient storage for river floodwater during periods of high tide. In the course of the feasibility and design studies the actual reduction in flood hazard was not quantified| but the design was carried out against specific combinations of tidal levels and fluvial flows. Recent research for MAFF at HR Wallingford has now made viable the assessment of the actual degree of flood risk| where flooding depends on the combination of two or more events. This paper presents a new joint probability appraisal of the standard of flood defence for the land around the inland bay| and demonstrates the conservatism incorporated in the original design methodology for flood risks. An examination of individual floods and surge tides and of the daily flow and tide records for a concurrent 18-year period has shown no positive correlation between concurrent high tides and river floods. An ISIS flow model of the Rivers Taff and Ely| the inland bay and the operation of the barrage structure was used to identify combinations of hydro-meteorological events that give specific levels in the inland bay. A statistical frequency assessment of these levels in the inland bay has provided 'return periods' for the still water level in the inland bay exceeding| for example| 7.5 m OD and 8.0 m OD. This frequency assessment was undertaken for sea levels with and without an allowance for future rise in mean sea level attributable to global warming. The ISIS modelling contained some conservative assumptions| notably the assumed coincidence between the peak of the river flow and high tide in the Bristol Channel| and the effect of these assumptions was investigated by some sensitivity tests. Finally| a best estimate of the return period for these levels in the inland bay was made using the sensitivity testing and the results of a study in 1994 of the effects of the operation of the barrage. It is concluded that the construction of the barrage is a significant flood defence benefit to Cardiff| which now has greater protection from flooding from the inland bay than the Thames Barrier provides for London. Flood risk from impoundment of the inland bay for the waterfront area remains very low even for the currently used scenarios for mean sea level rise due to global warming to the year 2100. 5770,2002,3,4,A novel reduction process of CO2 fixation by waste concrete treatment,A new process to fix anthropogenic carbon dioxide via treatment of waste concrete was proposed. The main reaction of the process is the extraction of calcium ions from waste concrete particles by use of pressurized carbon dioxide (several MPa in pressure). The extracted Ca2+ is deposited as calcium carbonate (CaCO3) particles when the pressure is reduced to the atmospheric pressure. The CaCO3 particles can either be disposed of directly or reused industrially for cement production. The former case is a direct disposal of CO; the latter case is an indirect disposal Of CO2| because the net mining amount of virgin limestone could be reduced. Energy consumption and cost for the fixation process Of CO2 emitted from a 100-MW thermal power plant by the proposed process was evaluated based on laboratory-scale experimental results. It was found that energy consumption for the operation was 3.5 MW per 100-MW power generation| and the fixation cost was about JPY 2100 per metricton of carbon. This result indicates that the present process is highly competitive with the previous CO2 fixation scenarios such as ocean sequestration. 5962,2002,2,4,A population study of the Blue-breasted Fairy-wren| Malurus pulcherrimus| at Dryandra| Western Australia,Over the years 1990-99| a colour-banded population of Blue-breasted Fairy-wrens| Malurus pulcherrimus| was studied at Dryandra State Forest in Eucalyptus wandoo woodland. Much of this work coincided with a study (by other workers) of the same species in patches of heathland scattered through wheatland at Wyalkatchem (1993-98). At Dryandra| groups of 2-4 adults lived all year round in territories averaging 2.5 ha; clutch size was two or three eggs (mean 2.8)| with more two-egg clutches laid in dry years| as at Wyalkatchem. The main difference between the two studies was in the timing of breeding. At Wyalkatchem the first clutches were laid in early August| whereas in Dryandra August is still cold| and no eggs were laid before mid-September. In wetter years laying ceased at Wyalkatchem towards the end of December but at Dryandra it continued into February. Individual nest success was low at both sites| but with a longer nesting season Dryandra groups renested more frequently and produced more fledglings (1.63 fledglings per group at Wyalkatchem| 1.93 at Dryandra). Annual survival of adults at Dryandra was c. 5% lower than for the Wyalkatchem birds| which suggests that the habitat for the species at the western edge of its distribution is sub-optimal. As at Wyalkatchem| productivity was at or above replacement level only in years of above-average rainfall. Since productivity at both sites was significantly reduced in drier years| the effect of forecast global warming causes concern for this species. Comparisons between M. pulcherrimus and the Red-winged Fairy-wren| M. elegans| illustrate how the group-living social organisation basic to all Malurus spp. can differ greatly between species as a result of differences in survival and productivity. 5860,2002,3,3,A proposed industrial-boiler efficiency program in Shanxi: potential CO2-mitigation| health benefits and associated costs,An industrial boiler-efficiency improvement program (IBEI) that focuses on simple. inexpensive measures to improve the operating efficiency of coal-fired industrial boilers in Shanxi| China. is presented. The potential mitigation of CO| emissions and its cost| based on this program. are calculated together with estimates of health benefits associated with the reduction of air pollution. The results show that. if the average efficiency of industrial boilers were improved from 60 to 70%. 3 million tons of coal could be saved. and CO2 emissions be reduced by 5 million tons annually at a cost of less than US$2 per ton of CO2. The health benefits are valued at about US$86 million per year. including the avoidance of about 700 premature deaths annually. The proposed IBEI program would. therefore provide an ideal case by which to address the issue of global warming in China and to achieve national goals concerning the growth of the economy. and environmental protection. (C) 2002 Elsevier Science Ltd. All rights reserved. 5886,2002,3,3,A review of environmental hazards and adsorption recovery of cleaning solvent hydrochlorofluorocarbons (HCFCs),Hydrochlorofluorocarbons (HCFCs) are being used as interim replacements for chlorofluorocarbons (CFCs) that cause significant stratospheric ozone depletion and global warming relating to the greenhouse effect: HCFCs under commercial uses such as cleaning solvents include HCFC-123 (2|2-dichloro-1|1|1-trifluoroethane)| HCFC-141b (1|1-dichloro-1-fluoroethane)| HCFC-225ca (3|3dichloro-1|1|1|2|2-pentafluoropropane)| and HCFC-225cb (1|3-dichloro-1|1|2|2|3-pentafluoropropane). From the environmental| ecological| and regulatory points of view| it is important to limit and control the emissions of these cleaning solvents from the surface finishing processes. Adsorption technology has been utilized for many years to recover organic vapors by using carbon-based or zeolite-based adsorbent. This article aims to introduce these HCFCs in terms of physiochemical properties| commercial uses| and environmental hazards (i.e.| stratospheric ozone depletion| global warming| and health & safety). Further| the main studies on the adsorption isotherm and desorption methods of these HCFCs by various adsorbents (i.e.| granular activated carbon| activated carbon fiber| and hydrophobic zeolite) are reviewed in this paper. (C) 2002 Elsevier Science Ltd. All rights reserved. 2948,2002,3,2,A structural decomposition analysis of air pollution from fossil fuel combustion in India,During the last decade| there has been worldwide concern with global climate change| which has been induced by greenhouse gases (GHGs) due to the use of fossil fuels. The CO2 emissions from fossil fuel combustion have been identified as the single most significant source of GHG emissions into the atmosphere. Realizing the need to control and regulate emissions of pollutants| the objective of the present study estimates the trend of CO2 SO2 and NOx between the periods 1991-92 and 1996-97. An input-output structural decomposition analysis approach is used to determine their sources of change. It also provides a set of alternative scenarios for the year 2001-2 and 2006-7. The sources of changes in the amount of CO2 SO2 and NOx emissions are categorized into four factors: the ecoefficiency| the structure of production| the structure of demand| and the volume of demand. Results indicate that the electricity sector contributes more towards direct| as well as indirect| emission coefficients. The petroleum product sector also contributes more in this respect. The dominant role is played by the structure of demand and the volume of demand. 5941,2002,2,4,A theoretical analysis on the local climate change induced by the change of landuse,The local climate change induced by the change of landuse| i.e.| the degeneration of vegetation is studied by the consideration of the equilibrium among radiation| phase change and convection in an air column and the energy balance condition on the ground surface. The result shows that the increase of ground albedo and the change of the surface heat flux as well as the decrease of the surface roughness length may induce the decrease of precipitation and the increase of temperature in the northern China| similar to the numerical simulation. Considering advection| this conclusion is also true except the amounts of the decrease of precipitation and the increase of temperature are changed. The decrease of precipitation and the increase of temperature will be more serious in case of global warming. 2932,2002,5,4,Accumulation of organic and inorganic carbon in Pliocene-Pleistocene sediments along the SW African margin,The Ocean Drilling Program Leg 175 recovered a unique series of stratigraphically continuous sedimentary sections along the SW African margin| an area which is presently affected by active coastal upwelling. The accumulation rates of organic and inorganic carbon are a major component of this record. Four Leg 175 sites (1082| 1084| 1085| 1087) are chosen as part of a latitudinal transect from the present northern to southern boundaries of the Benguela Current upwelling system| to decipher the Pliocene-Pleistocene history of biogenic production and its relationship with global and local changes in oceanic circulation and climate. The pattern of CaCO(3) and C(org) mass accumulation rates (MARs) over 0.25-Myr intervals indicates that the evolution of carbon burial is highly variable between the northern and the southern Benguela regions| as well as between sites that have similar hydrological conditions. This| as well as the presence over most locations of high-amplitude| rapid changes of carbon burial| reflect the partitioning of biogenic production and patterns of sedimentation into local compartments over the Benguela margin. The combined mapping of CaCO(3) and C(org) MARs at the study locations suggests four distinct evolutionary periods| which are essentially linked with major steps in global climate change: the early Pliocene| the mid-Pliocene warm event| a late Pliocene intensification of northern hemisphere glaciation and the Pleistocene. The early Pliocene spatially heterogeneous patterns of carbon burial are thought to reflect the occurrence of mass-gravitational movements over the Benguela slope which resulted in disruption of the recorded biogenic production. This was followed (3.5-3 Ma) by an episode of peak carbonate accumulation over the whole margin and| subsequently| by the onset of Benguela provincialism into a northern and a southern sedimentary regime near 2 Ma. This mid and late Pliocene evolution is interpreted as a direct response to changes in the ventilation of bottom and intermediate waters| as well as to dynamics of the subtropical gyral circulation and associated wind stress. (C) 2002 Elsevier Science B.V. All rights reserved. 2940,2002,2,4,Air pollutant combinations - Significance for future impact assessments on vegetation,Research on combinations of "classical" air pollutants such as SO2| NOx| acid deposition or O-3 has extensively been carried out in the eighties and early nineties of the last century. More recently| attention has been paid to the interactions between elevated CO2 concentrations and air pollutants since the importance of the direct effects of rising CO2 on vegetation on a global scale has been recognized and since there is evidence that elevated CO2 has the potential to mitigate negative effects of air pollutants. A short synopsis is provided of the state of the scientific knowledge on the effects of pollutant mixtures on vegetation focussing on combinations with O-3. Particular emphasis is laid on current uncertainties and gaps in assessing pollutant interactions involved in the modification of plant responses to predicted changes in climate and atmosphere. 5798,2002,3,4,Amelioration of global warming by controlled enhancement of the albedo and longevity of low-level maritime clouds,A technique is proposed for controlled enhancement of droplet concentrations in low-level maritime clouds| with corresponding increase in their albedo and longevity| thereby producing a cooling effect. It involves dissemination at the ocean surface of small seawater droplets which act as cloud condensation nuclei (CCN). It has low ecological impact. (C) 2002 Royal Meterorological Society 5784,2002,2,4,An analysis of daily maximum wind speed in northwestern Europe using generalized linear models,The basic climatological pattern and recent trends in daily maximum wind speed (DMWS) for the region 47.5degrees-65degreesN and 12.5degreesW-22.5degreesE are studied using gamma distributions within a generalized linear model. Between 1958 and 1998| DMWS has increased over the ocean in winter but weakened over continental Europe in summer. Large-scale circulation changes such as those of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) account for the strengthening wind over the ocean. Global warming may have impacted the regional wind climate. In particular| Southern Hemisphere temperature exhibits a significant effect on the distinct oceanic and continental trends in DMWS. It is suggested that the steady warming of the Southern Hemisphere during the last few decades may have forced the North Atlantic storm track to shift in such a way that storms are enhanced toward the northwestern oceanic area| but weakened throughout most of the European continent. 5811,2002,5,3,An atmospheric pCO(2) reconstruction across the Cretaceous-Tertiary boundary from leaf megafossils,The end-Cretaceous mass extinctions| 65 million years ago| profoundly influenced the course of biotic evolution. These extinctions coincided with a major extraterrestrial impact event and massive volcanism in India. Determining the relative importance of each event as a driver of environmental and biotic change across the Cretaceous-Tertiary boundary (KTB) crucially depends on constraining the mass of CO2 injected into the atmospheric carbon reservoir. Using the inverse relationship between atmospheric CO2 and the stomatal index of land plant leaves| we reconstruct Late Cretaceous-Early Tertiary atmospheric CO2 concentration (pCO(2)) levels with special emphasis on providing a pCO(2) estimate directly above the KTB. Our record shows stable Late Cretaceous/ Early Tertiary background pCO(2) levels of 350-500 ppm by volume| but with a marked increase to at least 2|300 ppm by volume within 10|000 years of the KTB. Numerical simulations with a global biogeochemical carbon cycle model indicate that CO2 outgassing during the eruption of the Deccan Trap basalts fails to fully account for the inferred pCO(2) increase. Instead| we calculate that the postboundary pCO(2) rise is most consistent with the instantaneous transfer of approximate to4|600 Gt C from the lithic to the atmospheric reservoir by a large extraterrestrial bolide impact. A resultant climatic forcing of +12 W(.)m(-2) would have been sufficient to warm the Earth's surface by approximate to7.5degreesC| in the absence of counter forcing by sulfate aerosols. This finding reinforces previous evidence for major climatic warming after the KTB impact and implies that severe and abrupt global warming during the earliest Paleocene was an important factor in biotic extinction at the KTB. 5761,2002,4,4,An efficient climate model with a 3D ocean and statistical-dynamical atmosphere,We describe a coupled climate model of intermediate complexity designed for use in global warming experiments. The atmospheric component is a two-dimensional (zonally averaged) statistical-dynamical model based on the Goddard Institute for Space Study's atmospheric general circulation model (GCM). In contrast with energy-balance models used in some climate models of intermediate complexity| this model includes full representation of the hydrological and momentum cycles. It also has parameterizations of the main physical processes| including a sophisticated radiation code. The ocean component is a coarse resolution ocean GCM with simplified global geometry based on the Geophysical Fluid Dynamics Laboratory modular ocean model. Because of the simplified geometry the resolution in the western boundary layers can be readily increased compared to conventional coarse resolution models| without increasing the model's computational requirements in a significant way. The ocean model's efficiency is also greatly increased by using a moderate degree of asynchronous coupling between the oceanic momentum and tracer fields. We demonstrate that this still allows an accurate simulation of transient behavior| including the seasonal cycle. A 100 years simulation with the model requires less than 8 hours on a state-of the art workstation. The main novelty of the model is therefore a combination of computational efficiency| statistical-dynamical atmosphere and 3D ocean. Long-term present-day climate simulations are carried out using the coupled model with and without flux adjustments| and with either the Gent-McWilliams (GM) parametrization scheme or horizontal diffusion (HD) in the ocean. Deep ocean temperatures systematically decrease in the runs without flux adjustment. We demonstrate that the mismatch between heat transports in the uncoupled states of two models is the main cause for the systematic drift. In addition| changes in the circulation and sea-ice formation also contribute to the drift. Flux adjustments in the freshwater fluxes are shown to have a stabilizing effect on the thermohaline circulation in the model| whereas the adjustments in the heat fluxes tend to weaken the global "conveyor". To evaluate the model's response to transient external forcing global warming simulations are also carried out with the flux-adjusted version of the coupled model. The coupled model reproduces reasonably well the behavior of more sophisticated coupled GCMs for both current climate and for the global warming scenarios. 2864,2002,4,4,An integrated model of soil| hydrology| and vegetation for carbon dynamics in wetland ecosystems,Wetland ecosystems are an important component in global carbon (C) cycles and may exert a large influence on global climate change. Predictions of C dynamics require us to consider interactions among many critical factors of soil| hydrology| and vegetation. However| few such integrated C models exist for wetland ecosystems. In this paper| we report a simulation model| Wetland-DNDC| for C dynamics and methane (CH4) emissions in wetland ecosystems. The general structure of Wetland-DNDC was adopted from PnET-N-DNDC| a process-oriented biogeochemical model that simulates C and N dynamics in upland forest ecosystems. Several new functions and algorithms were developed for Wetland-DNDC to capture the unique features of wetland ecosystems| such as water table dynamics| growth of mosses and herbaceous plants| and soil biogeochemical processes under anaerobic conditions. The model has been validated against various observations from three wetland sites in Northern America. The validation results are in agreement with the measurements of water table dynamics| soil temperature| CH4 fluxes| net ecosystem productivity (NEP)| and annual C budgets. Sensitivity analysis indicates that the most critical input factors for C dynamics in the wetland ecosystems are air temperature| water outflow parameters| initial soil C content| and plant photosynthesis capacity. NEP and CH4 emissions are sensitive to most of the tested input variables. By integrating the primary drivers of climate| hydrology| soil and vegetation| the Wetland-DNDC model is capable of predicting C biogeochemical cycles in wetland ecosystems. 5720,2002,3,4,Analytical study to minimise the heat losses from a propane powered 4-stroke spark ignition engine,The alarming rate at which the Earth's atmosphere is getting polluted| the increased impact of global warming on the weather conditions on Earth and the stringent anti-pollution laws imposed in certain countries are among the main reasons for the search for alternatives to gasoline. Liquefied Petroleum Gas (LPG) (mainly propane) is among the many alternatives proposed to replace gasoline in the short term due to its excellent characteristics as a fuel for spark ignition (Sl) engines. This paper presents a discussion on the parameters that affect the engine's heat losses mainly during power stroke| with suggestions to minimise it. The effect of the equivalence ratio| compression ratio| spark plug location| and combustion duration at different speeds on the heat losses has been studied. (C) 2002 Elsevier Science Ltd. All| rights reserved. 5732,2002,2,4,Annual CO2 balance of a subarctic fen in northern Europe: Importance of the wintertime efflux,The annual balance of CO2 was measured on a subarctic flark fen located in northern Finland (69degrees08'N| 27degrees17'E). Measurements were conducted using the micrometeorological eddy covariance method during the period from April 1998 to April 1999. Special emphasis was put on the importance of the wintertime CO2 balance as a component of the annual budget. The CO2 fluxes observed during the winter were relatively small (0.0055 mg CO2 m(-2) s(-1))| but due to the long duration of the snow cover period| they play an important role in the annual balance of CO2. The efflux during the coldest periods| when soil surface temperatures fell below -10degreesC| was enabled by markedly higher peat temperatures (close to 0degreesC) in deeper layers. The typical nighttime respiration observed in summer was -0.10 mg CO2 m(-2) s(-1). The net photosynthesis had a typical daytime peak value of about -0.20 mg CO2 m(-2) s(-1) in July. Corresponding with the instantaneous CO2 fluxes| the highest daily sink balances of about -9 g CO2 m(-2) d(-1) were observed in July| while the highest daily respiration balances of about 2.5 g CO2 m(-2) d(-1) were observed before and after the sink period. The CO2 balance for the winter period (105 g CO2 m(-2)) was greater than the absolute value of the total annual balance (-68 g CO2 m(-2))| which shows the importance of the wintertime efflux. After taking into account estimates for CH4 efflux and carbon leaching| an annual carbon balance of -7+/-5 g C m(-2) was obtained for the fen. 5877,2002,2,4,Anthropogenic and climate-change impacts on salt marshes of Jamaica Bay| New York City,Field studies and aerial photograph interpretation suggest that large sections of Jamaica Bay salt marshes in New York City near John F. Kennedy International Airport are deteriorating rapidly. The relatively recent salt marsh losses may be caused by a variety of factors| potentially interacting synergistically. Possible factors include reduced sediment input| dredging for navigation channels| boat traffic| and regional sea-level rise. Field work included aboveground biomass measurements of Spartina alterniflora| mapping plant community distribution| and documenting biogeomorphological indicators of marsh loss. Current productivity (standing crop biomass)| which ranged from approximately 700 to 1500 g m(-2)| was typical of healthy marshes in this region| in spite of other indicators of marsh degradation. Historical aerial photographs of several islands showed that sampled marshes have diminished in size by similar to 12% since 1959. Overall island low marsh vegetation losses since 1974 averaged 38%| with smaller islands losing up to 78% of their vegetation cover. Ground observations indicate that major mechanisms of marsh loss include increased ponding within marsh interiors| slumping along marsh edges| and widening of tidal inlets. Projections of future sea-level rise| using outputs from several global climate models and data from local tide gauges| in conjunction with a range of plausible accretion rates| suggest that under current stresses| Jamaica Bay salt marshes are unlikely to keep pace with accelerated rates of sea-level rise in the future. 2847,2002,2,4,Application of decision support system for sustainable management of water resources in the Azraq Basin - Jordan,Water scarcity in Jordan is a significant constraint to development| with limited available water and financial resources. As population and economic activity increase| it will be necessary to implement national strategies that seek to balance the present needs and those of future generations. Multiple variables associated with agricultural crops| industries| and the impact of climate change| were incorporated into a Decision Support System (DSS). The DSS utilized Analytical Hierarchy Process (AHP)| which resulted in the prioritization of sustainable water policies for management in the Azraq Basin. The inputs to the DSS were generated through application of Modflow (groundwater)| stochastic| and Penman Montieth models and through calculations of water productivity for agricultural and industrial sectors. The results of the DSS make recommendations as to how to enhance| long-term sustainability of water resources in Azraq| while allowing for water utilization and economic growth. It is recommended for future planning that further research of the impacts to water resources must be conducted at local and national levels and linked to regional and global climate change prediction. It can be concluded that the DSS tool and AHP are potentially positive contributions to the process of decision-making for selection and ranking of alternatives and policies and for help in solving problems that include conflicting criteria. 5953,2002,3,3,Application of environmental impact assessments to tribo-components - A case study on plain bearings for automotive engines,Life Cycle Assessment (LCA) is conducted for four types of plain bearings used for automotive engines. Equivalent CO2 emission (ECE) is used as the index of the environmental impact for global warming| and is compared among different chemical compositions and different manufacturing processes. Three types of aluminum alloy bearings| all of which are in the market| show little difference in ECE| irrespective of different lining constituents or the addition of an interlayer. Copper-lead alloy bearings with overlay| on the other hand| show an ECE value approximately 2.7 times as high as that for the aluminum bearings| the increment originating from the overplating process. If higher fatigue resistance of the aluminum alloy bearings is taken into consideration and their size could be reduced maintaining the same level of performance| further advantage would be found for their use. 5857,2002,4,4,Application of PIXE technique to studies on global warming/cooling effect of atmospheric aerosols,During the last decade| the importance of global warming has been recognized worldwide| Atmospheric aerosols play an important role in the global warming/cooting effects| The physicochemical properties of aerosol particles are fundamental to understanding such effects. In this study| the PIXE technique was applied to measure the average chemical properties of aerosols. Micro-PIXE was also applied to investigate the mixing state of the individual aerosol particle. The chemical composition data were used to estimate the optical properties of aerosols. The average values of aerosol radiative forcing were -1.53 w/m(2) in Kyoto and +3.3 w/m(2) in Nagoya| indicating cooling and warming effects respectively. The difference of radiative forcing in the two cities may be caused by the large difference in chemical composition of aerosols. (C) 2002 Elsevier Science B.V. All rights reserved. 5691,2002,4,4,Approaches of fusion science to global warming from the perspective of thermofluid research,Scientific interest in the environmental and meteorological fields has been focused on the estimation of the temperature rise on the earth in the near and far future. The temperature rise is estimated by a gas transfer flux. It is very difficult to measure and estimate the gas transfer rate resulting from the air-sea interaction because of very high Schmidt number (Sc) turbulent fluid flow with free surface deformation. On the other hand| the utilization of high Prandtl number (Pr) fluid flows| like a Flibe| with free surface as a coolant in an advanced magnetic fusion reactor and as a chamber protection scheme in an inertial confinement fusion reactor have been considered. From the perspective of thermofluid research| it would be very important to discuss on some common aspects between fusion nuclear technology and global warming problem. Since the thermal diffusivities of high Pr or Se fluids are very small| when the high temperature or concentration regions appear on the free surface caused by plasma radiation or carbon-dioxide gas absorption| respectively| the scalar transport from the free surface to the bulk flow must be very slow compared with the fluid motion. In this paper| some common aspects between the heat transfer of high Pr free surface flow in fusion engineering and the mass transfer of high Sc free surface flow in the global warming problem are discussed. (C) 2002 Elsevier Science B.V. All rights reserved. 5693,2002,4,2,Are natural climate forcings able to counteract the projected anthropogenic global warming?,A two-dimensional global climate model is used to assess the climatic changes associated with the new IPCC SRES emissions scenarios and to determine which kind of changes in total solar irradiance and volcanic perturbations could mask the projected anthropogenic global warming associated to the SRES scenarios. Our results suggest that only extremely unlikely changes in total solar irradiance and/or volcanic eruptions would be able to overcome the simulated anthropogenic global warming over the century. Nevertheless| in the critical interval of the next two decades the externally-driven natural climate variability might possibly confuse the debate about temperature trends and impede detection of the anthropogenic climate change signal. 5848,2002,2,4,Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland,Despite the importance of arbuscular mycorrhizae to the functioning of terrestrial ecosystems (e.g. nutrient uptake| soil aggregation)| and the increasing evidence of global warming| responses of arbuscular mycorrhizal fungi (AMF) to climate warming are poorly understood. In a field experiment using infrared heaters| we found effects of warming on AMF after one growing season in an annual grassland| in the absence of any effects on measured root parameters (weight| length| average diameter). AMF soil hyphal length was increased by over 40% in the warmed plots| accompanied by a strong trend for AMF root colonization increase. In the following year| root weight was again not significantly changed| and AMF root colonization increased significantly in the warmed plots. Concentration of the soil protein glomalin| a glycoprotein produced by AMF hyphae with importance in soil aggregation| was decreased in the warmed plots. Soil aggregate water stability| measured for five diameter size classes| was also decreased significantly. In the following year| soil aggregate weight in two size classes was decreased significantly| but the effect size was very small. These results indicate that ecosystem warming may have stimulated carbon allocation to AMF. Other factors either influenced glomalin decomposition or production| hence influencing the role of these symbionts in soil aggregation. The observed small changes in soil aggregation| if widespread among terrestrial ecosystems| could have important consequences for soil carbon storage and erosion in a warmed climate| especially if there are cumulative effects of warming. 5783,2002,3,4,Aspects of peat conservation and water management,An extended water regime model was used for calculating the evapotranspiration| groundwater recharge| and peat mineralization (CO2 and N release) for various fen locations with grassland utilization in dependence on the groundwater level. The results show that an increasing groundwater level leads to a strong decline of the actual evapotranspiration E-t. For example| increasing the groundwater level from 30 to 120 cm diminishes the E-t by up to 230 mm a(-1). A positive groundwater recharge only takes place at groundwater levels of 90 cm and more. At smaller distances the capillary rise into the rooting zone during the summer months is greater than the water seepage during the winter months| so that a negative groundwater recharge-balance is reached in the course of a year. The CO2- and the N-release| as well as the annual decline in peat thickness| increase significantly with rising groundwater levels. The results show that varying the groundwater level can influence the water regime and the peat mineralization significantly. The lower the groundwater level the less is the peat decomposition. The demand for a groundwater level as small as possible is| however; limited by an agricultural utilization of the fens. Choosing the optimum groundwater level should consider the aims (1) peat mineralization| (2) gas emission (CO2| CH4; N2O)| and (3) crop production. If a grassland utilization is supposed to be made possible and all three aims above are given equal importance| the groundwater level should be maintained at 30 cm. At this distance| about 90 % of the optimum plant output can be reached. The peat mineralization can be reduced to 30 to 40 % of the maximum peat mineralization. The gas emission amounts to -50-60 % of the maximum value. 2889,2002,2,4,Assessment of the risk of solar ultraviolet radiation to amphibians. III. Predictions of impacts in selected northern midwestern wetlands,Solar ultraviolet radiation| especially UVB (280-320 nm)| has been hypothesized to be at least partially responsible for adverse effects (e.g.| declines and malformations) in amphibian species throughout the world. Evaluation of this hypothesis has been limited by the paucity of high-quality UV dose-response data and reliable estimates of typical UV doses that occur in amphibian habitats. In this preliminary risk assessment for effects of UV radiation on amphibians| dose-response relationships quantified in outdoor experiments were compared with UV exposure estimates for 26 wetlands in northern Minnesota and Wisconsin. A comparison of wetland doses| derived from model prediction| historical data| and dissolved organic carbon (DOC) characterization| with experimental effects levels for green (R. clamitans)| northern leopard (R. pipiens)| and mink (R. septentrionalis) frogs indicated that the risk of mortality and malformations due to UV exposure is low for the majority of wetlands evaluated. Wetland UV dose| averaged over the entire breeding season| exceeded effects doses for mortality for all three species in two of the 26 wetlands examined and for one species in an additional wetland. On the basis of evidence that shorter term doses caused mortality in amphibian larvae| 3-day doses were also evaluated. In three of the wetlands examined| 3-day doses in excess of 85% of full sunlight(the level that appeared to trigger effects in controlled experimentation) occurred at frequencies ranging 22-100% for all three species and at frequencies ranging from 15% to 58% for R. pipiens and R. septentrionalis in three additional wetlands. Risk of malformation in R. pipiens was apparent in five of the 26 wetlands evaluated. Overall| estimated UVB doses in 21 of the wetlands never exceeded experimental effects doses for mortality or malformations. These results suggest that most amphibians are not currently at significant risk for UVB effects in northern Minnesota and Wisconsin wetlands. However| continued reduction of ozone and other global climate change effects may increase UV doses in wetlands| suggesting that the risk of UV to amphibians should continue to be monitored and studied. 5733,2002,4,3,Atmospheric chemistry of CF3CFHOCF3: Reaction with OH radicals| atmospheric lifetime| and global warming potential,[1] Smog chamber/FTIR techniques were used to study the OH radical initiated oxidation of CF3CFHOCF3 in 700 torr of air diluent at 296 K. Relative rate techniques were used to measure k(1)(OH + CF3CFHOCF3) = (1.4 +/- 0.3) x 10(-15) cm(3) molecule(-1) s(-1). The atmospheric lifetime of CF3CFHOCF3 is estimated to be 40 years. The IR spectrum of CF3CFHOCF3 was measured and used to estimate a global warming potential (relative to CO2| 100 year time horizon) for CF3CFHOCF3 of 4500. Results are discussed with respect to the previous literature data. 5815,2002,5,4,Atmospheric nitrous oxide: patterns of global change during recent decades and centuries,Data from weekly global measurements of nitrous oxide from 1981 to the end of 1996 are presented. The results show that there is more N2O in the northern hemisphere by about 0.7 +/- 0.04 ppbv| and the Arctic to Antarctic difference is about 1.2 +/- 0.1 ppbv. Concentrations at locations influenced by continental air are higher than at marine sites| showing the existence of large land-based emissions. For the period studied| N2O increased at an average rate of about 0.6 ppbv/year (similar to0.2%/year) although there were periods when the rates were substantially different. Using ice core data| a record of NO2 can be put together that goes back about 1000 years. It shows pre-industrial levels of about 287 +/- 1 ppbv and that concentrations have now risen by about 27 ppbv or 9.4% over the last century. The ice core data show that N2O started increasing only during the 20th century. The data presented here represent a comprehensive view of the present global distribution of N2O and its historical and recent trends. (C) 2002 Published by Elsevier Science Ltd. 5748,2002,4,4,Behavioural models of population growth rates: implications for conservation and prediction,Conservation biologists often wish to predict how vertebrate populations will respond to local or global changes in conditions such as those resulting from sea-level rise| deforestation| exploitation| genetically modified crops| global warming| human disturbance or from conservation activities. Predicting the consequences of such changes almost always requires understanding the population growth rate and the density dependence. Traditional means of directly measuring density dependence are often extremely difficult and have the problem that if the environment changes then it is necessary to remeasure the density dependence. We describe an alternative approach that does not require such long datasets and can be used to predict the density dependence under novel conditions. Game theory can be used to describe behavioural decisions that individuals make in response to interference| prey depletion| territorial behaviour or social dominance| and the resultant fitness consequences. It is then possible to predict how survival or reproductive output changes with population size. From this we can then make predictions about the responses of populations to environmental changes. We will illustrate how this can be applied to a range of species and a range of applied problems. 5823,2002,3,4,Bringing scientific knowledge from research to the professional fields: the case of the thermal and airflow design of buildings in tropical climates,The need for construction projects to be sustainable is becoming more widely recognised| partly because of diminishing world energy resources| and partly because recent world developments (for example| global warming and increasing oil prices) have made those involved in construction more aware of a new approach to building. We often hear now of buildings with a high environmental rating| of sustainable development| and of improved comfort. The stated objective is to construct comfortable buildings| which use little energy and produce little pollution. This desire on the part of construction project leaders has led to some problems amongst architects. engineers and university researchers who tend to work in isolation from each other. However. the only way to achieve an overall improvement in building design is by close collaboration between the various participants| from when the first sketch of the future building is made. Of course| this task appears difficult because these participants have different approaches| training and 'tools of the trade'. This article aims to show that efficient cooperation between the professionals involved is possible. We will see that by producing an instructive working document| understandable by all and based on expert rules| it is possible to produce buildings which are adapted to the climate. and to spread the scientific knowledge to the more practical professions. We will illustrate our ideas by describing the methodology we used for a building project in the tropics. Finally. we will present a summary for the period 1997-2001 and will show the impact that such collaborations have had on the design of buildings in tropical climates. (C) 2002 Elsevier Science B.V. All rights reserved. 5734,2002,3,4,C4F8O/O-2/N-based additive gases for silicon nitride plasma enhanced chemical vapor deposition chamber cleaning with low global warming potentials,In this study| N2O and NO were added as additive gases to C4F8O/O-2 for plastria enhanced chemical vapor deposition (PECVD) silicon nitride chamber cleaning and their effects on the emission properties of perfluorocarbon compounds (PFCs) were investigated. The cleaning rate| destruction and removal efficiencies (DREs)| and million metric tons of carbon equivalent (MMTCE) were studied as a function of flow rates of PFCs and additive gases. The use of C4F8O/O-2 alone showed the highest cleaning rate and the lowest emission properties at the cleaning condition of 20%C4F8O/80%O-2| working pressure of 500 mTorr| and 13.56 MHz rf power of 350 W. By the addition of about 20% NO or 20% N2O to the optimized C4H8O/O-2| the additional reduction of MMTCE higher than 50% could be obtained. The addition of NO resulted in lower MMTCE compared to that in the case of the addition of N2O mostly due to the higher silicon nitride cleaning rate in the latter case. 5712,2002,3,2,Carbon and nutrient cycles,Soil erosion and off-site transport of nutrients are reducing soil productivity and impacting water bodies across the world. Additionally| anthropogenic activities are increasing the atmospheric concentrations of carbon dioxide (CO2)| methane (CH4)| nitrous oxide (N2O)| and nitric oxide (NO) that contribute to global warming. We want to present the concept that nutrient management plans should incorporate soil organic carbon (SOC) management to reduce soil erosion| cycle macro- and micronutrients| increase nutrient use efficiency| and conserve air| soil| and water quality. Plant-derived materials are the primary source of carbon (C) in soil organic matter (SOM)| with C being the most abundant constituent and common partner of nitrogen (N)| phosphorous (P)| and sulfur (S). Manures| compost| and other organic sources can help cycle organic C and other nutrients. Organic C can contribute to forming chelate compounds that increase the availability of essential micronutrients that interchange with the root surface. Management practices that increase C inputs| help reduce erosion| and increase SOC improve soil quality factors such as cation exchange capacity| water holding capacity| aggregate formation| porosity| and drainage. Carbon management and nutrient cycling should be an integral part of nutrient management plans for maintaining the sustainability of our biosphere. 5847,2002,5,3,Carbon dioxide and climate over the past 300 Myr,The link between atmospheric CO2 levels and global warming is an axiom of current public policy| and is well supported by physicochemical experiments| by comparative planetary climatology and by geochemical modelling. Geological tests of this idea seek to compare proxies of past atmospheric CO2 with other proxies of palaeotemperature. For at least the past 300 Myr| there is a remarkably high temporal correlation between peaks of atmospheric CO2| revealed by study of stomatal indices of fossil leaves of Ginkgo| Lepidopteris| Tatarina and Rhachiphyllum| and palaeotemperature maxima| revealed by oxygen isotopic (6180) composition of marine biogenic carbonate. Large and growing databases on these proxy indicators support the idea that atmospheric CO2 and temperature are coupled. In contrast| CO2-temperature uncoupling has been proposed from geological time-series of carbon isotopic composition of palaeosols and of marine phytoplankton compared with foraminifera| which fail to indicate high CO2 at known times of high palaeotemperature. Failure of carbon isotopic palaeobarometers may be due to episodic release of CH4| which has an unusually light isotopic value (down to -110parts per thousand| and typically -60parts per thousanddelta(13)C) and which oxidizes rapidly (within 7-24 yr) to isotopically light CO2. Past CO2 highs (above 2000 ppmv) were not only times of catastrophic release of CH4 from clathrates| but of asteroid and comet impacts| flood basalt eruptions and mass extinctions. The primary reason for iterative return to low CO2 was carbon consumption by hydrolytic weathering and photosynthesis| perhaps stimulated by mountain uplift and changing patterns of oceanic thermohaline circulation. Sequestration of carbon was promoted in the long term by such evolutionary innovations as the lignin of forests and the sod of grasslands| which accelerated physicochemical weathering and delivery of nutrients to fuel oceanic productivity and carbon burial. 5681,2002,4,3,Carbon in the atmosphere and terrestrial biosphere in the 21st century,The release of carbon dioxide from fossil-fuel combustion and land-use change has caused a significant perturbation in the natural cycling of carbon between land| atmosphere and oceans. Understanding and managing the effects of this disruption on atmospheric composition and global climate are likely to be amongst the most pressing issues of the 21st century. However| the present-day carbon cycle is still poorly understood. One remarkable feature is that an increasing amount of atmospheric carbon dioxide appears to be being absorbed by terrestrial vegetation. I review the recent evidence for the magnitude and spatial distribution of this 'terrestrial carbon sink'| drawing on current research on the global atmospheric distribution and transport of carbon dioxide| oxygen and their isotopes; direct measurement Of CO2 fluxes above various biomes; and inventories of forest biomass and composition. I review the likely causes of these carbon sinks and sources and their implications for the ecology and stability of these biomes. Finally| I examine prospects and key issues over coming decades. Within a few years| satellite measurements of atmospheric CO2 and forest biomass| coupled with 'real-time' biosphere-atmosphere models| will revolutionize our understanding of the terrestrial carbon cycle. Controlling deforestation and managing forests has the potential to play a significant but limited part in reaching the goal of stabilizing atmospheric CO2 concentrations. However| there are likely to be limits to the amount of carbon storage possible in natural vegetation| and| in the long term| terrestrial carbon storage may be unstable| with the potential to accelerate rather than brake global warming. 2947,2002,3,4,Carbon storage and sequestration by urban trees in the USA,Based on field data from 10 USA cities and national urban tree cover data| it is estimated that urban trees in the coterminous USA currently store 700 million tonnes of carbon ($14|300 million value) with a gross carbon sequestration rate of 22.8 million tC/yr ($460 million/year). Carbon storage within cities ranges from 1.2 million tC in New York| NY| to 19|300 tC in Jersey City| NJ. Regions with the greatest proportion of urban land are the Northeast (8.5%) and the southeast (7.1%). Urban forests in the north central| northeast| south central and southeast regions of the USA store and sequester the most carbon| with average carbon storage per hectare greatest in southeast| north central| northeast and Pacific northwest regions| respectively. The national average urban forest carbon storage density is 25.1 tC/ha| compared with 53.5 tC/ha in forest stands. These data can be used to help assess the actual and potential role of urban forests in reducing atmospheric carbon dioxide| a dominant greenhouse gas. Published by Elsevier Science Ltd. 5778,2002,2,4,Causes and consequences of thermal tolerance limits in rocky intertidal porcelain crabs| genus Petrolisthes,Vertical zonation of intertidal organisms| from the shallow subtidal to the supralittoral zones| is a ubiquitous feature of temperate and tropical rocky shores. Organisms that live higher oil the shore experience larger daily and seasonal fluctuations in microhabitat conditions| due to their greater exposure to terrestrial conditions during emersion. Comparative analyses of the adaptive linkage between physiological tolerance limits and vertical distribution are the most powerful when the study species are closely related and occur in discrete vertical zones throughout the intertidal range. Here| I summarize work on (lie physiological tolerance limits of rocky intertidal zone porcelain crab species of the genus Petrolisthes to emersion-related heat stress. In the eastern Pacific| Petrolisthes species live throughout temperate and tropical regions| and are found in discrete vertical intertidal zones in each region. Whole organism thermal tolerance limits of Petrolisthes species| and thermal limits of heart and nerve function reflect microhabitat conditions. Species living higher in the intertidal zone are more eurythermal than low-intertidal congeners| tropical species have the highest thermal limits| and the differences in thermal tolerance between low- and high-intertidal species is greatest for temperate crabs. Acclimation of thermal limits of high-intertidal species is restricted as compared to low-intertidal species. Thus| because thermal limits of high-intertidal species are near current habitat temperature maxima| global warming could most strongly impact intertidal species. 5843,2002,3,4,CFC phase-out: have we met the challenge?,In 1974 Nobel prize winners Rowland and Molina proposed that chlorofluorocarbons (CFCs) were stable enough to reach the stratosphere| where| under intense solar radiation they released Cl atoms that could destroy stratospheric ozone protecting the earth's surface from UV rays| The CFC industry funded both scientific studies to test the Rowland and Molina hypothesis and programmes to identify potential replacements| front which the HFCs emerged as likely candidates. After 5 years it was concluded. on the best scientific evidence available| that stratospheric ozone was being depleted at similar to3% per decade| but sufficient time was available for an orderly phase-out. Although the USA and a few other countries stopped the use of CFCs in aerosols little further work was done until 1985 when the CFC debate was renewed following the discovery of stratospheric ozone depletion over the Antarctic during its spring. Manufacturers restarted their RD programmes; governments negotiated the Montreal Protocol in 1987 agreeing the partial phase-out of the CFCs. As a result of subsequent amendments CFCs have now been phased-out in the developed world and HCFCs will follow over the next two decades. This paper reviews What has been achieved and what remains to be done. Has the world-Aide effort been successful in protecting the ozone layer? Have "acceptable" alternatives been found for the CFCs/HCFCs in their various applications? (C) 2002 Published by Elsevier Science B.V. 2892,2002,4,3,Challenges for mycorrhizal research into the new millennium,Some future directions for mycorrhizal research are discussed. Data from The IPCC Third Assessment Reports 2001 on elevated carbon dioxide the concentration and consequences regarding global climate change| form the basis for arguments that a better understanding of the mycorrhizal activities with regard to controlling carbon flow and plant nutrient flow is essential. Mycorrhiza can be regarded as energy and nutrient switches in the plant roots and it is suggested that more studies on mycorrhizal carbon relations are necessary. The impact of the genomic research era on mycorrhizal research is suggested to be of major importance during the years to come| and it is claimed that stronger interactions between different disciplines will be essential. 5864,2002,4,4,Changes in Antarctic Peninsula tropospheric temperatures from 1956 to 1999: A synthesis of observations and reanalysis data,The surface warming at Faraday station in the western Antarctic Peninsula is one of the largest observed anywhere over the last 50 years| yet the physical mechanisms driving this climate change are poorly understood. In this paper we synthesize radiosonde temperature observations from three Peninsula stations and NCEP-NCAR reanalysis data in order to examine contemporaneous regional tropospheric temperature trends (1956-99)| which may in turn help us to understand better the causes of the surface warming. The reanalysis data are utilized in two ways: (i) to provide long-term mean monthly offsets between Faraday| which ceased radiosonde observations in 1982| and two other stations in the region having more recent data| Bellingshausen and Marambio| in order to create post-1982 simulated Faraday data; (ii) after having any spurious trends and bias removed| to provide directly a monthly value for Faraday when no equivalent value from regional observations is available. Using available months of overlap| a comparison between temperature observations and simulated data suggests that the latter are a reasonable facsimile of the former. The synthesized time-series of tropospheric temperatures reveal a statistically significant mean annual tropospheric (850-300 hPa) warming above Faraday between 1956 and 1999 of similar to0.027 +/- 0.022degreesC year(-1). Winter and summer both show a warming trend| with significance varying with height and season. Annually| the mean tropospheric warming is half that at the surface| Unlike the surface warming| the calculated tropospheric warming trend is no greater than observed at other Antarctic stations| and indeed is not significantly greater than the background global warming trend for most of the period examined. Thus| we cannot dismiss the possibility that the Peninsula surface warming may simply be a response to a global warming magnified by the observed strong regional feedback between sea-ice extent and surface temperature during winter. Copyright (C) 2002 Royal Meteorological Society. 5772,2002,3,3,Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol,The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However| controversy over the use of biological means to absorb or reduce emissions of CO2 (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions| and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social| environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals. 5703,2002,4,3,Changing trends in sulfur emissions in Asia: Implications for acid deposition| air pollution| and climate,In the early 1990s| it was projected that annual SO2 emissions in Asia might grow to 80-110 Tg yr(-1) by 2020. Based on new high-resolution estimates from 1975 to 2000| we calculate that SO2 emissions in Asia might grow only to 40-45 Tg yr(-1) by 2020. The main reason for this lower estimate is a decline of SO2 emissions from 1995 to 2000 in China| which emits about two-thirds of Asian SO2. The decline was due to a reduction in industrial coal use| a slow-down of the Chinese economy| and the closure of small and inefficient plants| among other reasons. One effect of the reduction in SO2 emissions in China has been a reduction in acid deposition not only in China but also in Japan. Reductions should also improve visibility and reduce health problems. SO2 emission reductions may increase global warming| but this warming effect could be partially offset by reductions in the emissions of black carbon. How SO2 emissions in the region change in the coming decades will depend on many competing factors (economic growth| pollution control laws| etc.). However a continuation of current trends would result in sulfur emissions lower than any IPCC forecasts. 5828,2002,4,4,Characterization of Arabidopsis photolyase enzymes and analysis of their role in protection from ultraviolet-B radiation,DNA photolyases are enzymes which mediate the light-dependent repair (photoreactivation) of UV-induced damage products in DNA by direct reversal of base damage rather than via excision repair pathways. Arabidopsis thaliana contains two photolyalses specific for photoreactivation of either cyclobutane pyrimidine dimers (CPDs) or pyrimidine (6-4)pyrimidones (6-4PPs)| the two major UV-B-induced photoproducts in DNA. Reduced FADH and a reduced pterin were identified as cofactors; of the native Arabidopsis CPD photolyase protein. This is the first report of the chromophore composition of any native class II CPD photolyase protein to our knowledge. CPD photolyase protein levels vary between tissues and with leaf age and are highest in flowers and leaves of 3-5-week-old Arabidopsis plants. White light or UV-B irradiation induces CPD photolyase expression in Arabidopsis tissues. This contrasts with the 6-4PP photolyase protein which is constitutively expressed and not regulated by either white or UV-B light. Arabidopsis CPD and 6-4PP photolyase enzymes can remove UV-B-induced photoproducts from DNA in planta even when plants are grown under enhanced levels of UV-B irradiation and at elevated temperatures although the rate of removal of CPDs is slower at high growth temperatures. These studies indicate that Arabidopsis possesses the photorepair capacity to respond effectively to increased UV-Binduced DNA damage under conditions predicted to be representative of increases in UV-B irradiation levels at the Earth's surface and global warming in the twenty-first century. 5940,2002,3,3,Clean and secure energy for the twenty-first century,"As energy demand world-wide continues to rise| fuelling the expanding economy| the twin problems of security of supply and rising carbon dioxide emissions have risen high in the global agenda. Can economic growth be sustained without increasing energy demand? Is the prospect of global warming and the destabilisation of the weather machine so daunting that a global carbon tax should be instituted? Can renewable energy replace fossil fuel in the next 50 years? Will nuclear energy re-emerge as the high technology solution to our problems?" 5764,2002,2,4,Climate change and water resources in Lebanon and the Middle East,While the extent of human-induced global warming is inconclusive| the vulnerability of natural systems to rapid changes in climate patterns is regarded as one of the most challenging issues in recent years. Water resources are a main component of natural systems that might be affected by climate change. This paper characterizes water resources in several Middle Eastern countries and evaluates regional climate predictions for various scenarios using general circulation models. The country of Lebanon is selected as a case study for an in-depth investigation with potential impacts on the water budget and soil moisture as indicators. Adaptation measures are assessed| with a focus on no-regret actions in the context of local socioeconomic and environmental frameworks. 5754,2002,2,4,Climate change and winter survival of perennial forage crops in eastern Canada,Severe winter climatic conditions cause recurrent damage to perennial forage crops in eastern Canada. Predicted increases of 2 to 6 C in minimum temperature during winter months due to global warming will likely affect survival of forage crops. Potential impacts of climate change on overwintering of perennial forage crops in eastern Canada were assessed using climatic indices reflecting risks of winter injuries related to cold intensity and duration| lack of snow cover| inadequate cold hardiness| soil heaving| and ice encasement. Climatic indices were calculated for 22 agricultural regions in eastern Canada for the current climate (1961-1990) and future climate scenarios (2010-2039 and 2040-2069). Climate scenario data were extracted from the first-generation Canadian Global Coupled General Circulation Model. Compared with current conditions| the hardening period in 2040 to 2069 would be shorter by 4.0 d| with a lower accumulation of hardiness-inducing cool temperatures. The period during which a temperature less than or equal to-15degreesC can occur (cold period) would be reduced by 23.8 d| and the number of days with snow cover of at least 0.1 m would be reduced by 39.4 d. Consequently| the number of days with a protective snow cover during the cold period would be reduced by 15.6 d. Under predicted future climate| risks of winter injury to perennial forage crops in eastern Canada will likely increase because of less cold hardening during fall and reduced protective snow cover during the cold period| which will increase exposure of plants to killing frosts| soil heaving| and ice encasement.
5845,2002,2,3,Climate change as a threat to tourism in the Alps,Switzerland's economy depends heavily on tourism. For many alpine areas in the country| winter tourism is the most important source of income| and snow-reliability is one of the key elements of the offers made by tourism in the Alps. The financial viability of winter tourism| however| depends on sufficient snow conditions. The lack of snow at the end of the 1980s left a lasting imprint on the tourism industry. If the assumptions of the impacts of climate change hold true| snow cover in the Swiss Alps will diminish| and this will| in turn| jeopardise the tourism industry. 85% of Switzerland's current ski resorts can be designated as snow-reliable. If climate change occurs| the level of snow-reliability will rise from 1200 m up to 1800 m over the next few decades. Only 44% of the ski resorts would then still be snow-reliable. While some regions may be able to maintain their winter tourism with suitable adaptation strategies| others would lose all winter tourism due to a diminishing snow pack. Despite global warming| it is impossible to exclude the possibility of winters with heavy snowfall in the future (e.g. the winter of 1998/99| particularly February 1999). Climate change must be viewed as a catalyst that is reinforcing and accelerating the pace of structural changes in tourism. Today| adaptation strategies are predominant in tourism (e.g. artificial snow production). As an industry that will be severely affected by climate change| however| tourism will increasingly have to focus on mitigation strategies (e.g. less greenhouse gas emissions by tourism traffic). 5805,2002,2,4,Climate change in India inferred from geothermal observations,[1] Temporal variations in surface ground temperature impart a signal to the subsurface thermal regime that is captured in borehole temperature-depth profiles. Seventy temperature-depth profiles in India| located between 12degrees and 28degreesN| are analyzed to infer past changes in ground temperature. These profiles exhibit predominantly positive anomalous temperatures relative to the background thermal regime beginning at depths of 75-150 m and increasing toward the surface. This pattern is consistent with warming over the past century. An interpretation in terms of linear surface temperature change indicates warming of about 0.9degrees +/- 0.1 degreesC over the past 150 years. Relatively complete surface air temperature (SAT) records from meteorological stations near the boreholes indicate similar rates of warming over the last century. A combined analysis of borehole temperatures and SAT records yields a long-term| preobservational mean temperature| 0.8degrees +/- 0.1 degreesC lower than the 1961-1990 mean SAT. When the most recent decade is included directly in the analysis| the average total warming in India from the early 1800s to the late 1990s is similar to1.2degrees C. 5865,2002,2,4,Climate change in the Colorado Rocky Mountains: Free air versus surface temperature trends,A high elevation data set of surface temperatures from the Front Range of the Rocky Mountains in Colorado| USA| is analysed for evidence of long-term change (1952-98). Sites range from the high plains of Colorado (1509 m) to the alpine tundra (3749 m). Systematic changes in surface-based lapse rates are uncovered| with absolute cooling at the hi-hest elevations| but little temperature change on the high plains. There is lapse-rate steepening at the higher elevations (>3000 m). A synoptic analysis using gridded pressure data shows lapse rate changes to be largely independent of synoptic type. Radiosonde ascents from Denver (1956-98) and Grand Junction (1946-98) are used to derive air equivalent temperatures (AETs) at the same elevations as the surface records. AETs show a contrasting temporal trend| with absolute warming at all levels. Furthermore| free-air lapse rates are weakening at higher elevations| the warming becoming stronger with height. A comparison of the two data sets through derivation of free-air-surface temperature differences shows that the alpine tundra zone of the high Rockies is becoming a progressively stronger heat sink. Possible explanations include increased snow cover| enhanced air movement over the surface and decreased solar radiation input. The heat sink enhancement has led to rapid cooling in the alpine tundra that could not be predicted from the free-air record| casting doubt upon the strong dependence on free-air temperature changes in climate modelling when investigating the potential effects of global warming in mountainous regions. In addition| these local surface trends are of the opposite sign to global and other regional trends identified in many recent observational and modelling studies. Copyright (C) 2002 Royal Meteorological Society. 2862,2002,2,4,Climate change scenarios and runoff response in the Mulde catchment (Southern Elbe| Germany),The impact of a climate change scenario on regional climate conditions and runoff characteristics has been investigated for the Mulde catchment| a meso-scale sub-basin of the Elbe in Germany. First| the semi-distributed| conceptual model HBV-D has been successfully applied to simulate discharge for present climate conditions. Further| the expanded downscaling method (EDS) was calibrated and applied to observed global circulation fields in order to produce local climate input data for HBV-D. Finally| the coupled atmosphere-ocean model ECHAM4/OPYC3| driven by a climate change scenario| provided simulated global circulation patterns for application with EDS. The regionalised scenario conditions then served as input to HBV-D in order to investigate the impact of global climate change on regional hydrology. The results indicate that an obvious increase in temperature is accompanied by a clear tendency to reduced precipitation over the investigated area for the next 100 years. These conditions lead to a decrease in simulated mean discharges of the Mulde. The study is considered to be a contribution for regional impact studies on global climate change. At the same time| it demonstrates existing shortcomings and limitations of current climate impact research. (C) 2002 Elsevier Science B.V. All rights reserved. 5789,2002,4,2,Climate feedbacks at the tundra-taiga interface,Feedbacks| or internal interactions| play a crucial role in the climate system. Negative feedback will reduce the impact of an external perturbation| a positive feedback will amplify the effect and could lead to an unstable system. Many of the feedbacks found in the climate system are positive; thus| for example| increasing CO2 levels will increase temperature| reduce the snow cover| increase the absorption of radiation and hence increase temperature further. The most obvious feedbacks| such as the snow example quoted above| are already included within our models of the climate and earth system. Others| such as the impact of increasing forest cover due to global warming| are only just being included. Others| such as| the impact of global warming on the northern peatlands and the impact of freshwater flows on the Arctic Ocean are not yet considered. The contrast in surface characteristics between low tundra vegetation to high taiga forest is considerable. The contrast is greatest in the winter| when the tundra is snow covered but the trees of the taiga protrude through the snow pack| and is probably the greatest contrast found on the land surface anywhere. This variation causes massive changes in the energy fluxes at the surface and hence the temperature conditions on the ground and within the atmosphere. There will be large resultant changes in the vegetation development| the carbon fluxes| the permafrost and the hydrology. The Arctic is already experiencing change and it is essential for us to understand the basic processes| and how these interact| to be confident of our predictions of environmental change in the future. 5786,2002,2,4,Climate variations and the physiological basis of temperature dependent biogeography: systemic to molecular hierarchy of thermal tolerance in animals,The physiological mechanisms limiting and adjusting cold and heat tolerance have regained interest in the light of global warming and associated shifts in the geographical distribution of ectothermic animals. Recent comparative studies| largely carried out on marine ectotherms| indicate that the processes and limits of thermal tolerance are linked with the adjustment of aerobic scope and capacity of the whole animal as a crucial step in thermal adaptation on top of parallel adjustments at the molecular or membrane level. In accordance with Shelford's law of tolerance decreasing whole animal aerobic scope characterises the onset of thermal limitation at low and high pejus thresholds (pejus = getting worse). The aerobic scope of an animal indicated by falling oxygen levels in the body fluids and or the progressively limited capacity of circulatory and ventilatory mechanisms. At high temperatures| excessive oxygen demand causes insufficient oxygen levels in the body fluids| whereas at low temperatures the aerobic capacity of mitochondria may become limiting for ventilation and circulation. Further cooling or warming beyond these limits leads to low or high critical threshold temperatures (T-c) where aerobic scope disappears and transition to an anaerobic mode of mitochondrial metabolism and progressive insufficiency of cellular energy levels occurs. The adjustments of mitochondrial densities and their functional properties appear as a critical process in defining and shifting thermal tolerance windows. The finding of an oxygen limited thermal tolerance owing to loss of aerobic scope is in line with Taylor's and Weibel's concept of symmorphosis| which implies that excess capacity of any component of the oxygen delivery system is avoided. The present study suggests that the capacity of oxygen delivery is set to a level just sufficient to meet maximum oxygen demand between the average highs and lows of environmental temperatures. At more extreme temperatures only time limited passive survival is supported by anaerobic metabolism or the protection of molecular functions by heat shock proteins and antioxidative defence. As a corollary| the first line of thermal sensitivity is due to capacity limitations at a high level of organisational complexity| i.e. the integrated function of the oxygen delivery system| before individual| molecular or membrane functions become disturbed. These interpretations are in line with the more general consideration that| as a result of the high level of complexity of metazoan organisms compared with simple eukaryotes and then prokaryotes| thermal tolerance is reduced in metazoans. A similar sequence of sensitivities prevails within the metazoan organism| with the highest sensitivity at the organismic level and wider tolerance windows at lower levels of complexity. However| the situation is different in that loss in aerobic scope and progressive hypoxia at the organismic level define the onset of thermal limitation which then transfers to lower hierarchical levels and causes cellular and molecular disturbances. Oxygen limitation contributes to oxidative stress and| finally| denaturation or malfunction of molecular repair| e.g. during suspension of protein synthesis. The sequence of thermal tolerance limits turns into a hierarchy| ranging from systemic to cellular to molecular levels. (C) 2002 Published by Elsevier Science Inc. 2885,2002,2,2,Climate-mediated energetic constraints on the distribution of hibernating mammals,To predict the consequences of human-induced global climate change| we need to understand how climate is linked to biogeography(1). Energetic constraints are commonly invoked to explain animal distributions| and physiological parameters are known to vary along distributional gradients(2). But the causal nature of the links between climate and animal biogeography remain largely obscure(2|3). Here we develop a bioenergetic model that predicts the feasibility of mammalian hibernation under different climatic conditions. As an example| we use the well-quantified hibernation energetics of the little brown bat (Myotis lucifugus) to parameterize the model(4). Our model predicts pronounced effects of ambient temperature on total winter energy requirements| and a relatively narrow combination of hibernaculum temperatures and winter lengths permitting successful hibernation. Microhabitat and northern distribution limits of M. lucifugus are consistent with model predictions| suggesting that the thermal dependence of hibernation energetics constrains the biogeography of this species. Integrating projections of climate change into our model predicts a pronounced northward range expansion of hibernating bats within the next 80 years. Bioenergetics can provide the simple link between climate and biogeography needed to predict the consequences of climate change. 5943,2002,2,4,Climatic change and quasi-oscillations in central-west Argentina summer precipitation: main features and coherent behaviour with southern African region,Summer rainfall variability (October to March) shows inter-annual to multi-decadal fluctuations over a vast area of subtropical Argentina between 28degreesS-38degreesS and 65degreesW-70degreesW. Statistically significant oscillations of quasi-period in the bands of 18-21| 6| 4 and 2 years can be found throughout the region and intra-regionally| though the latter are variable. The lower frequency variation produces alternating episodes of above and below normal rainfall each lasting roughly 9 years. This quasi-fluctuation appears to be shared with the summer rainfall region of South Africa and were in-phase related one another until mid-1970s. The teleconnection between both subtropical regions could be generated by an atmospheric-oceanic bridge through the global sea surface temperatures (SSTs)| particularly those of the equatorial-tropical South Atlantic. From mid-1970s| the alternating wet and dry pattern has been interrupted in the Argentine region producing the longest| as yet unfinished| wet spell of the century| Thus| a significant change of the long-term variation was observed around 1977 toward lower frequencies. Since then the statistical model that explains more than 89% of the variance of the series until 1977| diverges from the observed values in the 1980s and 1990s. In addition the Yamamoto statistical index| employed to detect a climatic jump| reaches its major value in 1973 at the beginning of the current long wet spell. Therefore the change could be located between 1973 and 1977. Application of the t-student's test gives significant differences of mean values or pre-1977 and post-1977 sub-samples from both individual time series and the regional index series. The spectral analysis also shows changes in energy bands in concordance with the features of the change that occurred from mid-1970s. The change gives rise to a significant increment of more than 20% in average of normal rainfall over the region. Conversely| a drought between mid-1980s and the 1990s has been observed in the South African counterpart with severe characteristics| thereby continuing the quasi-18-year oscillation. Consequently| the low-frequency coherent behaviour between both the Argentine and South African regions is lost from the mid-1970s. The analysis of association of wet/dry spells and warm/cold| El Nino/La Nina episodes appears to be not significant at scales of year-to-year variability although at decadal to multi-decadal scales the association could be relevant. More than one process of multi-decadal variability of global SSTs could influence the Argentine summer rainfall region and the former bi-decadal teleconnection. Finally| potential hypothetical factors of change are discussed| such as the strengthening of direct and indirect mechanisms of moisture flux transport associated with global warming| low-level atmospheric circulation changes and/or to SSTs mean condition long-term variations over tropical and subtropical South Atlantic and South Pacific oceans. 5695,2002,2,4,Climatology of yellow sand (Asian sand| Asian dust or Kosa) in East Asia,In order to study climatology of yellow sand (Asian sand| Asian dust or Kosa) in East Asia| secular fluctuation in China| Korea and Japan in the recent 30 years was presented. The number of days with sand-dust storm at five stations in China Hotan| Zhangye| Minqin| Jurh and Beijing| decreases a lot at the former three stations| but changed little at the latter two stations. Suggesting that the recent global warming is more evident in Xinjiang and Gansu| where the frequency of cold air invasions from the higher latitudes is decreasing. But| the eastern parts of Mongolia| inner Mongolia| and North China encounter stronger cyclones in early spring as a result of global warming. These cyclones bring cold air from higher latitudes| causing severe dust storms. Secular variation in the annual days with sand-dust storms in China and Kosa days in Korea and Japan show a parallel change with higher frequency from 1975 to 1985. This may be related to the higher frequency of La Nina years. However| different tendency was shown in the period from 1986 to 1996. Since 1996 or 1997| a sharp increase is clear| which may be caused by the developed cyclones in East Asia as well as human activities| and stronger land degradation under La Nina conditions. Anomalies of the total number of stations with Kosa days were discussed in accordance with some synoptic meteorological conditions such as the differences between Siberian anticyclone and Aleutian cyclone center at 500 hPa level during the previous winter. 5885,2002,3,3,CO2 credit or energy credit in emission trading?,Emission trading is a good concept and approach to tackle global warming. However| what "currency" or "credit" should be used in the trading has remained a debatable topic. This paper proposed an "Energy Credit" concept as an alternative to the "CO2 credit" that is currently in place. From the thermodynamic point of view| the global warming problem is an "energy balance" problem. The energy credit concept is thought to be more thermodynamically correct and tackles the core of the global warming problem more directly. The Energy credit concept proposed can be defined as: the credit to offset the extra energy trapped/absorbed in the earth (and its atmosphere) due to the extra anthropogenic emission (or other activities) by a country or company. A couple of examples are given in the paper to demonstrate the concept of the Energy credit and its advantages over the CO2 credit concept. (C) 2002 Published by Elsevier Science Ltd. 2845,2002,2,4,Combined nuclear and mitochondrial DNA sequences resolve generic relationships within the Cracidae (Galliformes| Aves),The Cracidae is one of the most endangered and distinctive bird families in the Neotropics| yet the higher relationships among taxa remain uncertain. The molecular phylogeny of its 11 genera was inferred using 10|678 analyzable sites (5|412 from seven different mitochondrial segments and 5|266 sites from four nuclear genes). We performed combinability tests to check conflicts in phylogenetic signals of separate genes and genomes. Phylogenetic analysis showed that the unrooted tree of ((curassows| horned guan) (guans| chachalacas)) was favored by most data partitions and that different data partitions provided support for different parts of the tree. In particular| the concatenated mitochondrial DNA (mtDNA) genes resolved shallower nodes| whereas the combined nuclear sequences resolved the basal connections among the major clades of curassows| horned guan| chachalacas| and guans. Therefore| we decided that for the Cracidae all data should be combined for phylogenetic analysis. Maximum parsimony (MP)| maximum likelihood (ML)| and Bayesian analyses of this large data set produced similar trees. The MP tree indicated that guans are the sister group to (horned guan| (curassows| chachalacas))| whereas the ML and Bayesian analysis recovered a tree where the horned guan is a sister clade to curassows| and these two clades had the chachalacas as a sister group. Parametric bootstrapping showed that alternative trees previously proposed for the cracid genera are significantly less likely than our estimate of their relationships. A likelihood ratio test of the hypothesis of a molecular clock for cracid mtDNA sequences using the optimal ML topology did not reject rate constancy of substitutions through time. We estimated cracids to have originated between 64 and 90 million years ago (MYA)| with a mean estimate of 76 MYA. Diversification of the genera occurred approximately 41-3 MYA| corresponding with periods of global climate change and other Earth history events that likely promoted divergences of higher level taxa. 5918,2002,3,4,Comparison of greenhouse gas emissions from solid pig manure during storage versus during composting with respect to different dry matter contents,The green house gas emissions from pig manure during storage were compared with those during composting. The manure was prepared artificially by mixing liquid pig manure with different amounts of straw giving dry matter contents of 14%| 18% and 22%. The incubations were carried out for 97 days at 25 degreesC in 100 L scale. GC equipped with an FID| ECD and WLD detected the concentrations of methane| nitrous oxide| oxygen and carbon dioxide. Ammonia emissions were measured by titration. The global warming potential| calculated in CO(2) equivalents per kg dry matter of excreta were obtained by use of the specific global warming potential (100 year time horizon) for nitrous oxide and methane. The indirect global warming potential of ammonia was calculated by additional use of the specific emission factor of 0.01| which means that 1% of emitted ammonia is converted to nitrous oxide. The most important gas for global warming was found to be nitrous oxide. This gas contributed to 71 to 85% to total CO(2) equivalents. At low dry matter contents methane becomes more important and contributes to maximum 28% of total CO(2) equivalents. The global warming potential of ammonia amounted only up to 14%. For relatively low dry matter contents of 14 and 18% the composting process reduced CO(2) equivalents to 28 to 55% of the values from storage. With high straw amendment (22% dry matter content) the storage emitted only 65% of the CO(2) equivalents from composting. The amendment of high amounts of wheat straw to manure with low dry matter content reduced the relatively high emissions from storage process much better than composting of manure with low dry matter content. 5728,2002,4,4,Comparison of satellite altimetry to tide gauge measurement of sea level: Predictions of glacio-isostatic adjustment,Modern rates of sea level change are of interest because of concerns that global warming may be causing glacier retreat. Both tide gauges and satellite radar altimetry are used to measure the present rates of change in sea level. Tide gauges measure sea level relative to the ocean floor whereas the reference for satellite altimetry is the earth's center. A numerical model of deformation of the earth's solid surface and its geoid forced by melting ice sheets| both past and present| is used to predict the present rate of sea level change as measured by tide gauges and satellites. Sea level change observed by both tide gauges and satellites are predicted to be spatially nonuniform. Considering only past ice sheets tide gauges in glaciated regions would record a fall in sea level of -13 mm yr(-1)| whereas satellite altimetry would record a rise in sea level of 0.7 mm yr(-1). In the region peripheral to the glaciated zone a tide gauge would record a rise in sea level (3 mm yr(-1)) in contrast to a predicted fall in sea level (-0.3 mm yr(-1)) recorded with satellite altimetry. Near regions once glaciated| the rate of sea level change as recorded by satellite decays more rapidly than the tide gauge sea level signature and so isostatic adjustment caused by past ice sheets contributes proportionately less to the modern rate of sea level change as measured by satellites than by tide gauges. At regions distant from glaciated areas both tide gauges and satellites would record a slight (-0.3 mm yr(-1)) sea level fall. The immediate elastic sea level response from melting of present ice sheets yields a similar signature for data from both tide gauges and satellite altimetry. Recorded sea level would fall near the meltwater source and at great distance from the source would rise approximately 122% of the oceanwide average sea level amount. Therefore glacio-isostatic processes will contaminate the sea level record measured by satellite less than the tide gauge record. 5911,2002,4,4,Complex coupled system dynamics and the global warming policy problem,A Public Domain| once a velvet carpet of rich buffalo-grass and grama| now an illimitable waste of rattlesnake-bush and tumbleweed| too impoverished to be accepted as a gift by the states within which it lies. Why? Because the ecology of this Southwest happened to be set on a hair trigger. 5846,2002,4,3,Constraints on radiative forcing and future climate change from observations and climate model ensembles,The assessment of uncertainties in global warming projections is often based on expert judgement| because a number of key variables in climate change are poorly quantified. In particular| the sensitivity of climate to changing greenhouse-gas concentrations in the atmosphere and the radiative forcing effects by aerosols are not well constrained| leading to large uncertainties in global warming simulations(1). Here we present a Monte Carlo approach to produce probabilistic climate projections| using a climate model of reduced complexity. The uncertainties in the input parameters and in the model itself are taken into account| and past observations of oceanic and atmospheric warming are used to constrain the range of realistic model responses. We obtain a probability density function for the present-day total radiative forcing| giving 1.4 to 2.4 W m(-2) for the 5-95 per cent confidence range| narrowing the global-mean indirect aerosol effect to the range of 0 to -1.2 W m(-2). Ensemble simulations for two illustrative emission scenarios suggest a 40 per cent probability that global-mean surface temperature increase will exceed the range predicted by the Intergovernmental Panel on Climate Change (IPCC)| but only a 5 per cent probability that warming will fall below that range. 5961,2002,2,4,Consumption of fungal sporocarps by Yellowstone grizzly bears,Sign of grizzly bears (Ursus arctos horribilis) consuming fungal sporocarps (mushrooms and truffles) was observed on 68 occasions during a study of radiomarked bears in the Yellowstone region| 1977-96. Sporocarps also were detected in96 grizzly bear feces. Most fungi consumed by Yellowstone's grizzly bears were members of the Boletaceae (Suillus spp.)| Russulaceae (Russula spp. and Lactarius sp.)| Morchellaceae (Morchella elata)| and Rhizopogonaceae. Consumption of false truffles (Rhizopogon spp.) was indicated by excavations that were deeper| on average (1.1 dm)| than excavations for mushrooms (0.6 dm). Consumptionof sporocarps was most frequent during September (7% of all activity)| although median numbers of sporocarps excavated at feeding sites peaked during both August and September (22-23 excavations/site). Almost all consumption (75%) occurred on edaphically harsh sites typically dominated by lodgepole pine (Pinuscontorta). At broad scales| consumption of sporocarps was most likely where these types of lodgepole pine-dominated sites were extensive or where high-elevation sites supporting mature whitebark pine (P. albicaulis) were rare. The number of sporocarps excavated at a feeding site was greatest when cone crops ofwhitebark pine were small and in stands with abundant lodgepole pine. At finescales| consumption of fungi was positively associated with lodgepole pine basal area and negatively associated with total ground vegetation cover. Becauseof the strong association of sporocarp consumption with lodgepole pine and its disassociation at broad scales with availability of whitebark pine seeds| consumption of mushrooms and truffles by grizzly bears will likely increase in the Yellowstone ecosystem with global warming. Lodgepole pine is predicted to increase and whitebark pine to decline with global warming. 5939,2002,2,3,Continued declines of black abalone along the coast of California: are mass mortalities related to El Nino events?,The intertidal black abalone Haliotis cracherodii has experienced mass mortalities along the coast of California| USA| since the mid-1980s. Mortality is due to infection by a pathogen that leads to a fatal wasting disease called 'withering syndrome'| where the foot of the abalone atrophies until it can no longer adhere to the substratum. Massive die-offs due to withering syndrome were first noted on the Channel Islands in 1986| and by 1992 withering syndrome was observed near Point Conception on the mainland and was suspected to be spreading northward up the coast of California. The timing of the initial mass mortalities following the strong 1982 to 1983 El Nino and an isolated outbreak of withering syndrome in 1988 at Diablo Cove| north of Point Conception| following warm water discharge from a power plant| led to the hypothesis that the onset of mass mortalities due to withering syndrome may be triggered by elevated seawater temperatures. We surveyed black abalone populations at 7 sites along the mainland coast of California (including 3 where withering syndrome was already present) from 1992 to 2001| a period spanning 2 El Nino events| to determine whether (1) withering syndrome and associated declines of black abalone were spreading northward up the coast; and (2) these mass mortalities of black abalone could be related to elevated seawater temperatures during El Nino events. Mass mortalities of black abalone due to withering syndrome were observed at the 5 most southern sites (> 90% decline in numbers in all size classes)| but not at the 2 most northern sites| and there was a clear pattern of decline from south to north over time. Massive die-offs of abalone were not exclusively associated with times of elevated sea surface temperatures due to El Nino. Nevertheless| rapid declines of abalone at 2 sites coincided with the strong 1997 to 1998 El Nino| and declines during El Nino events were faster than those during non-El Nino years. Abalone at the 2 most northern sites| where only slight declines occurred during the 1997 to 1998 El Nino| may not have been infected by disease. It appears| therefore| that in the presence of the pathogen| warm water conditions associated with El Nino may accelerate the development of withering syndrome and the rate of decline of black abalone. Consequently| anthropogenic disturbances| such as discharges of heated water or global warming| may increase the incidence of this fatal disease. 2874,2002,4,4,Continuity of climatological observations with automation temperature and precipitation amounts from AWOS (Automated Weather Observing System),Recent automation of meteorological observations affects homogeneity of the long-term climatological records| which are used to study climate change and variability. In order to avoid false conclusions regarding apparent climate trends| these records must be adjusted to account for biases caused by new instrumentation| computerized processing algorithms and relocation of the observing sites. This study of the effects of automation on two primary climatological elements| temperature and precipitation amounts| was conducted at five stations situated in various climatological regimes across Canada| where concurrent Automated Weather Observing System (AWOS) and manual observations were collected over the period of one year. The authors attempted to assess observations at higher temporal scales: average daytime and night-time temperature; daily maximum and minimum temperature; daily precipitation - in addition to the usual annual| seasonal or monthly precipitation. Individual hourly or daily observations of temperature were grouped according to meteorological conditions that either maximize or minimize instrumental and site differences| e. g.| sky cover and wind speed. Similar electronic temperature sensors were used by both the observer and AWOS| which resulted in a rather small instrumental bias: AWOS reported temperatures that were warmer by up to 0.2degreesC. The siting bias| caused by AWOS typically being installed in the middle of an airfield| was often much more pronounced due to the greater radiative cooling: on average AWOS reported temperature minima that were colder by up to 1.3degreesC. Differences between gauges| especially in resolution and height of the orifice above the ground| were identified as the main source of observed biases. It was not possible to quantify the siting portion of the overall bias. Precipitation was categorized according to the amounts reported by AWOS. In the category of light daily amounts up to 5 mm d(-1)| no consistent reliable relationship between AWOS and the observer could be established| while in the moderate to heavy category of amounts higher than 5 mm d(-1)| AWOS underestimates precipitation by up to 13%. Cases| when either the observer or AWOS reported some precipitation| while the other reported null| were also examined in detail. Over time periods of one month or longer| undercatch by the AWOS automated weighing gauge| as compared to the Type B gauge for rain and the Nipher gauge for snow| is quite severe| on the order of tens of percentage points. This study emphasizes that the availability of at least one or two years of concurrent conventional and automated observations is crucial to the development of adjustment factors| especially for observations of sub-diurnal resolution. With the growing demand for good quality sub- and diurnal resolution data for construction of scenarios of impacts of global climate change on humans and the environment| it is expected that more research on adjusting high temporal resolution data will be required and conducted in the future. 2849,2002,2,4,Contributions of current year photosynthate to fine roots estimated using a C-13-depleted CO2 source,The quantification of root turnover is necessary for a complete understanding of plant carbon (C) budgets| especially in terms of impacts of global climate change. To improve estimates of root turnover| we present a method to distinguish current- from prior-year allocation of carbon (C) to roots in global change experiments by using changes in C-13:C-12 ratios (delta(13)C values) resulting from application of C-13-depleted| tank-derived CO2. In a 4-year study examining effects of elevated CO2 and temperature on reconstructed Douglas-fir (Pseudotsuga mensiezii) ecosystems| delta(13)C patterns of fine roots and foliage were measured yearly. Native soil of low nitrogen (N) content was used| so plant N supply relied on natural soil N processes. Under these N-limited conditions| elevated CO2 or temperature did not affect the proportion of fine root C derived from current- year photosynthate. Regression analyses showed that 75% of fine root C originated from current- year photosynthate. The method is useful as an independent measure of the contribution of current- year photosynthate to root C and could be used to improve estimates of root C budgets with concurrent measurements of root C pools. We calculated a C-13 enrichment of root C relative to foliar C of 2%. This enrichment agrees with prior measurements of the enrichment of heterotrophic versus autotrophic plant tissues and must be accounted for when using shifts in foliar delta(13)C to calculate inputs of plant C into the soil. This enrichment probably contributes to the progressive enrichment in C-13 with increasing depth in soil profiles. 5958,2002,2,4,Contributions of hydrological processes to sea level change,We estimate the global mean sea level (GMSL) change using TOPEX/Poseidon satellite radar altimeter measurements and investigate possible contributions from water mass redistribution within the global. hydrological cycle using a few numerical models. We examine the global mean sea level change at seasonal| interannual| and long-term time scales. The atmospheric and hydrological models include the ECMWF operational atmospheric model and the NCEP/NCAR reanalysis system. The World Ocean Atlas 1998 and over 19 years' satellite sea surface temperature observations are used-to evaluate steric mean sea level change at different time scales. Both hydrological cycle and steric change provide important contribution to seasonal GMSL change. At interannual time scales| atmospheric water vapor variation shows good correlation to the altimeter observation and can introduce observable changes in the mean sea level. The snow water over Greenland and Antarctica estimated from the ECMWF model also shows encouraging interannual variability during the 1997/1998 El Nino period. Preliminary results show that thermal effect is a major but not a dominant contributor to long-term sea level rise| indicating that snow and ice melting associated With global warming may play an important role in driving GMSL rise. (C) 2002 Elsevier Science Ltd. All rights reserved. 5861,2002,3,4,Cross-section set and chemistry model for the simulation of c-C4F8 plasma discharges,Great interest exists in c-C4F8 (octafluorocyclobutane or perfluorocyclobutane) etching plasma discharges due to their selectivity and potential for decreasing global warming gas emissions. In order to allow computational exploration of the discharge physics| a numerical model for a c-C4F8 discharge has been constructed. A set of cross sections has been assembled for electron collisions with c-C4F8 based on a combination of ab initio calculations| beam measurements| and swarm (i.e.| electron transport coefficient) analysis. In addition| a chemical reaction set has been proposed and an axisymmetric numerical model has been used to test the cross section and chemical reaction set against experiments. Results show that measured trends are reproduced and absolute values are well represented. A mechanism is suggested for negative atomic fluorine ion (F-) behavior with respect to power. (C) 2002 American Institute of Physics. 5832,2002,2,3,Daily maximum and minimum temperature trends in a climate model,[1] The recent observed global warming trend over land has been characterised by a faster warming at night| leading to a considerable decrease in the diurnal temperature range (DTR). Analysis of simulations of a climate model including observed increases in greenhouse gases and sulphate aerosols reveals a similar trend in the DTR of -0.2degreesC per century| albeit of smaller magnitude than the observed -0.8degreesC per century. This trend in the model simulations is related to changes in cloud cover and soil moisture. These results indicate that the observed decrease in the DTR could be a signal of anthropogenic forcing of recent climate change. 5731,2002,2,4,Decomposition of peat from upland boreal forest: Temperature dependence and sources of respired carbon,[1] The response of large stores of carbon in boreal forest soils to global warming is a major uncertainty in predicting the future carbon budget. We measured the temperature dependence of decomposition for upland boreal peat under black spruce forest with sphagnum and feather moss understory using incubation experiments. CO2 efflux rates clearly responded to temperature| which ranged from -10degrees to +8degreesC by similar to2degreesC increments. At temperatures below 0degreesC| significant decomposition was observed in feather moss peat but not in wetter sphagnum peat. Above 0degreesC| decomposition was exponentially related to temperature| corresponding to a Q(10) (the ratio of the rate of CO2 evolution at one temperature divided by that at a temperature 10degreesC cooler) of 4.4 for feather moss and 3.1 for sphagnum peat. The greatest change in CO2 evolution rate with temperature occurred between -2degrees and 0degreesC| which coincided with the phase transition of soil water. We saw no large change in the rate of CO2 evolution between incubation experiments separated by a 6 month storage period for feather moss peat. Stable C isotope measurements of evolved CO2 and the rate of change of CO2 evolution with time suggest different substrates are used to sustain heterotrophic respiration above and below freezing. Radiocarbon signatures of CO2 respired from both types of peat reflected significant contributions from C fixed in the last 35 years ("bomb'' C-14) as well as C fixed prior to 1950. We observed no change in the Delta(14)C of respired CO2 with temperature. Isotopic signatures of peat components showed that a combination of substrates must contribute to the CO2 evolved in our incubations. Decomposition of fine roots (which made up less than 7% of the total peat C) accounted for similar to50% of respired CO2 in feather moss peat and for similar to30% of respired CO2 in sphagnum peat. Fine-grained (< 1 mm)| more humified material that makes up 60-70% of the bulk peat organic carbon contributed significantly to heterotrophic respiration (&SIM;30% in feather moss and &SIM;50% in sphagnum moss peat)| despite slow decomposition rates. Increased temperatures caused enhanced decomposition from all pools without changing their relative contributions. Because the contribution of peat decomposition is a small portion of total soil respiration at the study site| increased respiration rates would be difficult to measure as increased fluxes in the field. Nonetheless| sustained warming could lead to significant loss of C from these peat layers. 2915,2002,4,4,Defining nutritional constraints on carbon cycling in boreal forests - towards a less 'phytocentric' perspective,Growing interest in possible global climate change has underlined the need for better information concerning the way in which carbon partitioning between ecosystem components is influenced by constraints on nutrient availability. Micro-organisms play a fundamental role in the cycling of carbon and nutrients in all ecosystems but the role of fungi in particular is pivotal in boreal forest ecosystems. Traditional models of nutrient cycling are based on methods and concepts developed in agricultural systems where microorganisms are considered primarily as nutrient processors providing plants with inorganic nutrients. The filamentous nature of fungi| their ability to translocate carbon and nutrients between different substrates and the capacity of ectomycorrhizal fungi to utilise organic nutrients have all been largely ignored. In this article| a new model is suggested which emphasises competition for organic nutrients between decomposer organisms and plants| with the plants depending on their associated mycorrhizal fungi for nutrient acquisition. Antagonistic interactions involving nutrient transfer between decomposer and mycorrhizal fungi are proposed as important pathways in nutrient cycling. Due to the nutrient conservative features of decomposer fungi| inorganic nutrients are considered less important for plant nutrition. The implications of the new nutrient cycling model on the carbon balance of boreal forests are discussed. 5870,2002,2,3,Dependence of permafrost conditions on global warming: Comparison of models| scenarios| and paleoclimatic reconstructions,Permafrost-favorable climatic conditions for the 21st century as predicted by two coupled atmosphere-ocean general circulation models (ECHAM4/OPYC3 and HadCM3) were compared. The severity index [1] related to the air-frost index [2] was used to characterize the local climatic conditions favoring the formation of permafrost. Anthropogenic forcing scenarios involving a general increase in the atmospheric greenhouse gas concentration with and without anthropogenic sulfate aerosol emissions were considered. The model simulations were compared to paleoclimatic reconstructions of the southern boundaries of different permafrost zones for two past warm periods with different degrees of global warming. The method proposed for comparing the model results between themselves and with paleoclimatic data showed that the sensitivity of the continuous permafrost area to global warming differs substantially in different models but is virtually independent of the applied radiation forcing scenarios in an individual model. For the scenario with a constant atmospheric aerosol content| the results of the atmospheric general circulation models were compared to those produced by the IFA RAN climate model of intermediate complexity| whose sensitivity was found to be similar to the sensitivity of the ECHAM4/OPYC3 model. A comparison of the ECHAM4/OPYC3 results to paleoclimatic reconstructions showed that the southern boundary of continuous permafrost over the former USSR region in the Holocene optimum (6000 before present (BP)) is similar to the conditions in the mid-21st century as predicted by the ECHAM4/OPYC3 model with allowance for aerosol emissions. In the absence of aerosol emissions| these conditions were found to be in better agreement with the permafrost distribution during the Eemian interglacial (125 000 BP). 2908,2002,4,2,Detecting climate change at a regional scale: The case of France,[1] An optimal detection method| already used for global climate change detection| is applied to regional anthropogenic climate change detection| in the particular case of France. This case was chosen for the availability of high quality| statistically homogenized near- surface temperature observations on one hand| and high- resolution climate simulations over this region on the other hand. The detection is conducted on centered patterns| in order to only focus on pattern similarities between observations and model predictions. Detection is successful for 30- year trends of summer minimal daily temperatures at a 90% confidence level| while it failed on summer maximal daily and winter temperatures. This partial success is very encouraging as it shows for the first time the detection of a climate change signal at the regional scale which resembles the one computed by a regional climate model. 5829,2002,2,4,Determining critical pre- and post-anthesis periods and physiological processes in Lycopersicon esculentum Mill. exposed to moderately elevated temperatures,To determine the thermosensitive periods and physiological processes in tomato flowers exposed to moderately elevated temperatures| tomato plants (Lycopersicon esculentum Mill.| cv. NC 8288) were grown at 28/22 degreesC or 32/26 degreesC day/night temperature regimes and then transferred to the opposite regime for 0-15 d before or 0-24 h after anthesis. For plants initially grown at 28/22 degreesC| moderate temperature stress before anthesis decreased the percentage of fruit set per plant| but did not clarify the thermosensitive period. The same level of stress did not significantly reduce fruit set when applied immediately after anthesis. For plants initially grown at 32/26 degreesC| fruit set was completely prevented unless a relief period of more than 5 d was provided before anthesis. The same level of stress relief for 3-24 h after anthesis also increased fruit set. Plants were most sensitive to 32/26 degreesC temperatures 7-15 d before anthesis. Microscopic investigation of anthers in plants grown continuously at high temperature indicated disruption| of development in the pollen| endothecium| epidermis| and| stomium. This disruption was reduced| but. still observable in plants relieved from high temperature for 10 d before anthesis. 2858,2002,4,4,Determining effects of area burned and fire severity on carbon cycling and emissions in Siberia,The Russian boreal forest contains about 25% of the global terrestrial biomass| and even a higher percentage of the carbon stored in litter and soils. Fire burns large areas annually| much of it in low-severity surface fires - but data on fire area and impacts or extent of varying fire severity are poor. Changes in land use| cover| and disturbance patterns such as those predicted by global climate change models| have the potential to greatly alter current fire regimes in boreal forests and to significantly impact global carbon budgets. The extent and global importance of fires in the boreal zone have often been greatly underestimated. For the 1998 fire season we estimate from remote sensing data that about 13.3 million ha burned in Siberia. This is about 5 times higher than estimates from the Russian Aerial Forest Protection Service (Avialesookhrana) for the same period. We estimate that fires in the Russian boreal forest in 1998 constituted some 14-20% of average annual global carbon emissions from forest fires. Average annual emissions from boreal zone forests may be equivalent to 23-39% of regional fossil fuel emissions in Canada and Russia| respectively. But the lack of accurate data and models introduces large potential errors into these estimates. Improved monitoring and understanding of the landscape extent and severity of fires and effects of fire on carbon storage| air chemistry| vegetation dynamics and structure| and forest health and productivity are essential to provide inputs into global and regional models of carbon cycling and atmospheric chemistry. 5738,2002,3,4,Developing a sustainable energy strategy for a water utility. Part II: a review of potential technologies and approaches,Environmental legislation is increasing the amounts of bought-in electricity required for sewage treatment| and generating larger volumes of sewage sludge to be treated and disposed of Concurrently| concerns over global warming and food safety from sewage sludge recycling on agricultural land is augmenting the costs of conventional sewage and sludge treatment technologies and practices. This paper reviews some emerging technologies and practices that may assist in mitigating these problems in the future. In addition| a number of potential renewable energy technologies available to water companies are reviewed. Results suggest that through the take-up of new technologies| current and future water quality standards could be delivered in a more sustainable way. However| this series of papers also highlights that institutional and political conflicts may have inadvertently failed to recognise the wider effects of improving water quality and lessened the financial support necessary for their widespread take-up. It is also suggested that through the use of a Strategic Environmental Assessment (SEA) approach| stakeholders could gain a better understanding of the broader environmental effects of achieving certain water quality standards and develop policy and long-term investment strategies accordingly. However| to fulfil the information requirements of an SEA| an appropriate appraisal tool that considers many of these factors in unison is required| and a possible technique is suggested. (C) 2002 Elsevier Science Ltd. All rights reserved. 5817,2002,3,4,Development of a new gas absorption chiller heater - advanced utilization of waste heat from gas-driven co-generation systems for air-conditioning,Growing concern about global warming has directed much attention towards natural gas-driven co-generation systems (CGS). For wider use of CGS in Japan| innovative technologies to utilize the waste heat of CGS more efficiently for the air-conditioning of office buildings have been long required. Tokyo Gas has developed a high-performance gas absorption chiller heater with auxiliary waste heat recovers. This paper presents the results of the development| including a numerical cycle simulation and experiments for heating and cooling. (C) 2002 Published by Elsevier Science Ltd. 5856,2002,3,4,Development of a two-stage metal hydride system as topping cycle in cascading sorption systems for cold generation,Thermally driven sorption heat pumps compete to be an alternative to mechanically driven vapor compression heat pumps. They do not use CFC refrigerants and therefore have no ozone depletion potential and only a negligible global warming potential. However| their performance lacks behind| even if in the case of compression devices the efficiency of electricity generation is taken into account. The currently available sorption devices have a coefficient of performance (COP) for cooling of about 0.75 for single-effect systems and of 1.2 for double-effect systems. Since the temperatures and pressures under which sorption systems are operated differ widely| it has been suggested to combine sorption systems operating with different working pairs to form a cascading system| in which a topping cycle is producing cold and heat at a sufficiently high temperature level to be able to drive a bottoming cycle which also produces cold| thus increasing the COP. In this study| a two-stage metal hydride sorption device is investigated| which is used as a topping cycle in a cascading system. The system comprises the three metal hydrides LmNi(4.91)Sn(0.15)| LaNi4.1Al0.52Mn0.38 and Ti0.99Zr0.01V0.43Fe0.09Cr0.05Mn1.5 in two reactors each. It is operated with a driving temperature of 310 degreesC| releasing heat for driving a bottoming cycle at a temperature of 125 degreesC and producing cold at a temperature of 2 degreesC. With a half-cycle time of 15 min and using the reaction enthalpies and the exchanged amount of hydrogen| the heat and cold output of the system can be determined. The total cold production is 1.8 kW and the heat generation is around 1.5 kW. The COP is in the range of 0.9 and the coefficient of heat amplification around 0.75. If a double-effect lithium bromide-water system with the above-mentioned COP is used as the bottoming cycle of the cascading system an overall COP of 1.8-2 is expected. (C) 2002 Elsevier Science Ltd. All rights reserved. 5750,2002,2,3,Differences in the biological carbon pump at three subtropical ocean sites,[1] We report primary production of organic matter and organic carbon removal from three subtropical open ocean time-series stations| two located in the Atlantic and one in the Pacific| to quantify the biological components of the oceanic carbon pump. We find that within subtropical gyres| export production varies considerably despite similar phytoplankton biomass and productivity. We provide evidence that the removal of organic carbon is linked to differences in nutrient input into the mixed layer| both from eddy induced mixing and dinitrogen fixation. These findings contribute to our knowledge of the spatial heterogeneity of the subtropical oceans| which make up more than 50% of all ocean area and are thought to spread in the course of CO2- induced global warming. 2854,2002,2,4,Distributional change and conservation on the Andean flank: a palaeoecological perspective,Aim To review the insights that palaeoecology can offer on the threat posed to Andean communities by global climate change. Location The geographical focus is the eastern flank of the tropical Andes| with particular reference to Peru. Method The article presents a synthetic review of the problem. Results Species-rich communities of the eastern Andean flank are threatened both by development and climate change. If| as predicted| the cloudbase and frost line lifts 600 in elevation this century| there will be a substantial loss of cloud forest habitat. Palaeoecology provides insights on the location and nature of past ecotones| the continuity of niche availability| and estimates for rates and modes of migration. With further warming and drying of lower montane regions| upslope migration of species will be individualistic: a new equilibrium with the altered climate is unlikely to be attained. The zone of agriculture will move upslope faster than the migrating trees and so landscape conversion will negate the ability of some species to respond to the new conditions. Conservation of the lower reaches of modern cloud forest is advocated as a means to limit this foreseeable extinction event. Main Conclusions Climate change will induce changes in plant and animal communities. Human disturbance will invade climatically marginal agricultural lands at the pace of climate change. Rapid migratory response such as that witnessed at the onset of the Holocene may not be evident as climates warm| because Holocene climatic stability has reduced outlying upslope populations that may have served as expansion nuclei. Conservation must aim to maintain plant and animal niches| rather than particular communities of species. 5756,2002,3,3,Documenting no-till and conventional till practices using Landsat ETM plus imagery and logistic regression,The ability of agricultural lands to sequester carbon from the atmosphere and help mitigate global warming has the potential to add value to farmland through the development of carbon-credit trading. Crucial to the creation of a market-based carbon credit trading system is the monitoring and verification of agricultural practices that promote carbon storage. Using remotely sensed images for this purpose could prove more efficient and cost-effective than traditional land-based methods. Landsat Enhanced Thematic Mapper Plus (ETM+) imagery and logistic regression had >95% accuracy in verifying no-till fallow fields. Further research is needed to investigate the potential for this low-cost technology to assist in the monitoring and verification of practices that sequester carbon. Development of an accurate| low-cost| efficient means of monitoring and verifying carbon sequestering practices wilt further the development of cropland carbon credits| thus helping to mitigate global warming| and will add value to U.S. farmland.
5758,2002,4,4,Dramatic change in local climate patterns in the Amboseli basin| Kenya,The Amboseli basin| a semi-arid| open savannah area of southern Kenya| has experienced extensive changes in habitat since the early 1960's. The present report documents patterns of air temperature and rainfall in Amboseli for the 25-year period beginning 1976. Daily temperatures increased dramatically throughout this time period| at a rate almost an order of magnitude greater than that attributed to global warming. Mean daily maximum temperature increased more than did daily minimum (0.275 vs. 0.071degreesC per annum). Although increases in mean daily maxima were documented for all months of the year| they were greatest during the hottest months| February and March. Annual rainfall varied more than four-fold (x = 346.5 mm| SD = 120.0| range 132.0-553.4 mm)| yet did not exhibit any directional or other regular pattern of variability among years over this same 25-year period. Empirical as well as theoretical investigation of relations between such changes in climatic conditions and habitat characteristics are needed at local and regional as well as global scales. 5741,2002,3,4,Dry etching of SiO2 thin films with perfluoropropenoxide-O-2 and perfluoropropene-O-2 plasmas,In this work. the plasma etching characteristics of SiO2 thin films have been investigated using RF low discharges fed with C3F6O and C3F6 mixted with oxygen. The results have been compared with performances obtained with CF4-CHF3 gases. The research was aimed at studying the utilization of new fluorocarbons in SiO2 plasma etching with a lock impact on global warming. The following features have been investigated: SiO2 etch rate. SiO2/Si selectivity. contamination of silicon surfaces exposed to the plasma| and greenhouse gas emission. 5880,2002,2,4,Dung beetle diversity in South Africa: influential factors| conservation status| data inadequacies and survey design,Dung beetles are useful as indicators in conservation and global warming studies owing to their specialized regional and local distribution patterns. However| existing South African data are inadequate for indication at the necessary degree of spatial resolution. To improve the database| Survey methods need to Lie designed according to the spatial and temporal factors that influence dung beetle diversity. Across four major climatic regions| there are seven principal species distribution centres for dung beetles in which activity is influenced primarily by difference| in rainfall seasonality and temperature| Across these regions| generic endemism is largely concentrated around the coastline and in montane areas. The conservation status of endemic genera is discussed. At a local scale| spatial diversity is influenced primarily by soil| vegetation and dung type. Maximum local diversity of dung beetles is observed after rainfall and decreases as surface conditions become warmer and drier. After workshop discussions| a coarse-grained| asymmetrical gradsect survey grid has been designed according to vegetative| climatic and land-usage gradients across South Africa. It is suggested that each survey point across these regional gradients should comprise a quarter-degree square in which local ecological gradients should be surveyed for invertebrates| Baited pitfall trapping is an easy method to provide quantitative data for dung beetles across such environmental gradients. Lining up each catch on a tray provides a relatively quick way to compare the specimens| identify the species present| and provide a quantitative assessment of species abundance. Data collection may be conducted on one or more occasion.| to accommodate seasonal and daily variation in species occurrence. This exercise could identify localities suitable for ecotourism reserves representative of the variation in ecotypes across the country| particularly| in coastal| natural grass and wooded regions| where many invertebrate taxa are endangered by habitat fragmentation including some rare dung beetle species. 5763,2002,3,4,Dynamic current-zero behaviour of wall-stabilised arc in different arc-quenching media,SF6 gas is the medium currently used to quench the arc in gas circuit breakers (GCBs) and gas insulated switchgear (GIS). It has become increasingly necessary to look at alternatives to SF6 for the following reasons: (i) high cost| (ii) sensitivity to particle contamination| (iii) concerns regarding global warming and hence the possibility of imposed rules for decreased SF6 production. From a practical standpoint| the complete elimination of SF6 as an arc-extinguishing medium is improbable. On the other hand| a reduction in the amount of SF6 and the inclusion of a buffer gas is worthy of consideration. In order to determine the suitability of a buffer gas| it is necessary to understand the buffer gases' fundamental plasma properties. A comparative prediction of the thermal breakdown strengths of the following gases: SF6| N-2| O-2| air| CO2| H-2| He and N-2-PTFE after current-zero is presented. The thermophysical properties of a N-2-PTFE mixture are also calculated. A one-dimensional wall-stabilised arc model is solved numerically to determine the thermal breakdown strength of the aforementioned buffer gases in the presence of a uniform electric field intensity having a certain rate of rise. Calculations are done for two typical arc radii: 2.5 and 1.5 mm. Predictions confirm the suitability of He| CO2| N-2 and air as a buffer gas to SF6 and helium is found to be the best buffer choice. 2921,2002,5,4,Dynamics of Pleistocene population extinctions in Beringian brown bears,The climatic and environmental changes associated with the last glaciation (90|000 to 10|000 years before the present; 90 to 10 ka B.P.) are an important example of the effects of global climate change on biological diversity. These effects were particularly marked in Beringia (northeastern Siberia| northwestern North America| and the exposed Bering Strait) during the late Pleistocene. To investigate the evolutionary impact of these events| we studied genetic change in the brown bear| Ursus arctos| in eastern Beringia over the past 60|000 years using DNA preserved in permafrost remains. A marked degree of genetic structure is observed in populations throughout this period despite local extinctions| reinvasions| and potential interspecies competition with the short-faced bear| Arctodus simus. The major phylogeographic changes occurred 35 to 21 ka B.P.| before the glacial maximum| and little change is observed after this time. Late Pleistocene histories of mammalian taxa may be more complex than those that might be inferred from the fossil record or contemporary DNA sequences atone. 5840,2002,2,4,Earlier spring snowmelt in northern Alaska as an indicator of climate change,[1] Predictions of global circulation models (GCMs) that account for increasing concentrations of greenhouse gases and aerosols in the atmosphere show that warming in the Arctic will be amplified in response to the melting of sea ice and snow cover. There is now conclusive evidence that much of the Arctic has warmed in recent decades. Northern Alaska is one region where significant warming has occurred| especially during winter and spring. We investigate how the changing climate of northern Alaska has influenced the annual cycle of snow cover there and in turn| how changes in snow cover perturb the region's surface radiation budget and temperature regime. The focus is on Barrow| Alaska| for which comprehensive data sets exist. A review of earlier studies that documented a trend toward an earlier disappearance of snow in spring is given. Detection and monitoring activities at Barrow are described| and records of snow disappearance from other sites in the Alaskan Arctic are compared. Correlated variations and trends in the date of final snowmelt (melt date) are found by examining several independent time series. Since the mid-1960s the melt date in northern Alaska has advanced by 8 days. The advance appears to be a consequence of decreased snowfall in winter| followed by warmer spring conditions. These changes in snowfall and temperature are attributed to variations in regional circulation patterns. In recent decades| there has been a higher frequency of northerly airflow during winter that tends to diminish snowfall over northern Alaska. During spring| however| intrusions of warm moist air from the North Pacific have become more common| and these tend to accelerate the ablation of snow on the North Slope of Alaska. One result of an earlier melt date is an increase in the net surface radiation budget. At Barrow| net radiative forcing can exceed 150 W m(-2) on a daily basis immediately following the last day of snowmelt| and as a result of an 8-day advance in this event| we estimate an increase of similar to2 W m(-2) on an annual basis. Our results are in general agreement with earlier analyses suggesting that reductions in snow cover over a large portion of the Arctic on an annual basis have contributed to a warming of the Northern Hemisphere (NH). In addition| the terrestrial ecosystems of the region are very sensitive to snow cover variations. There is growing concern that these perturbations are anthropogenically forced and adapting to these environmental changes will have significant social and economic consequences. While observed decreases in NH snow cover are in broad agreement with GCM simulations| our analyses suggest that internal (or natural) shifts in circulation patterns underlie the observed variations. Continued monitoring and further study is needed to determine whether the earlier disappearance of snow cover in spring in northern Alaska is an indicator of greenhouse-forced global warming or is a manifestation of a more natural| long-term cycle of climate change. 5682,2002,5,4,Earth's biggest 'whodunnit': unravelling the clues in the case of the end-Permian mass extinction,The mass extinction that occurred at the end of the Permian period| 250 million years ago| was the most devastating loss of life that Earth has ever experienced. It is estimated that ca. 96% of marine species were wiped out and land plants| reptiles| amphibians and insects also suffered. The causes of this catastrophic event are currently a topic of intense debate. The geological record points to significant environmental disturbances| for example| global warming and stagnation of ocean water. A key issue is whether the Earth's feedback mechanisms can become unstable on their own| or whether some forcing is required to precipitate a catastrophe of this magnitude. A prime suspect for pushing Earth's systems into a critical condition is massive end-Permian Siberian volcanism| which would have pumped large quantities of carbon dioxide and toxic gases into the atmosphere. Recently| it has been postulated that Earth was also the victim of a bolide impact at this time. If further research substantiates this claim| it raises some intriguing questions. The Cretaceous-Tertiary mass extinction| 65 million years ago| was contemporaneous with both an impact and massive volcanism. Are both types of calamity necessary to drive Earth to the brink of faunal cataclysm? We do not presently have enough pieces of the jigsaw to solve the mystery of the end-Permian extinction| but the forensic work continues. 5927,2002,3,3,Economic growth and greenhouse gas emissions,Recent empirical research has examined the relationship between certain indicators of environmental degradation and income| concluding that in some cases an inverted U-shaped relationship| which has been called an environmental Kuznets curve (EKC)| exists between these variables. Unfortunately| this inverted U-shaped relationship does not hold for greenhouse gas emissions| One explanation of the absence of EKC-like behavior in greenhouse gas emissions is that greenhouse gases are special pollutants that create global| not local| disutility. But the international nature of global warming is not the only reason that prevents de-linking greenhouse gas emissions from economic growth. The intergenerational nature of the negative impact of greenhouse gas emissions may have also been an important factor preventing the implementation of greenhouse gas abatement measures in the past. In this paper we explore the effect that the presence of intergenerational spillovers has on the emissions-income relationship. We use a numerically calibrated overlapping generations model of climate-economy interactions| We conclude that: (1) the intertemporal responsibility of the regulatory agency| (2) the institutional capacity to make intergenerational transfers and (3) the presence of intergenerationally tagged impact of emissions constitute important determinants of the relationship between economic growth and greenhouse gas emissions. (C) 2002 Elsevier Science B.V. All rights reserved. 5813,2002,2,4,Economic impacts of global warming - A study of the fishing industry in North Norway,Several studies have been carried out on the possible physical and biological effects of global warming in the Barents Sea area. Based on these studies this paper discusses the effects global warming may have on the Barents Sea fisheries and the implications for the North Norwegian economy. The first has been Studied using the multispecies| multifleet model ECONMULT| and the latter by applying an Input-Output model. A range of possible environmental scenarios based on the physical and biological studies of the effects of global warming has been examined. Both positive and negative biological growth effects have been considered| changing the current growth rates by +/-25%. A more narrow range of management regimes has been applied| reflecting the current management rules and fishery policy in the region. The paper analyses the potential of global warming for changing the catches| profitability| employment impacts and income generation by the Barents Sea fisheries. (C) 2002 Elsevier Science B.V. All rights reserved. 5790,2002,2,2,Effect of global warming on snow ablation pattern in the Himalaya,The Himalaya has a large concentration of glaciers and permanent snowfields. During winter| most of the high-altitude regions experience snowfall| and snow cover plays an important role in the ecology of the region. Melting from seasonal snow cover during summer forms an important source of many rivers originating in the Higher Himalaya. Therefore| understanding of snow accumulation and ablation is important for utilization of the Himalayan water resource. Snowpack ablation is highly sensitive to climatic variations. Increase in atmospheric temperature can enhance energy exchange between the atmosphere and snowpack. This can increase snow-melting. Investigations suggest that climate of the earth has constantly changed in the course of time|during the past ten million years or so. During this time| the earth has experienced alternate cycles of warm and cold periods. The difference in global mean temperature between the Last Glacial Maximum and the present warm period is about 5 deg C.However| this slow rate of climate change probably changed in the 20th century due to rapid industrialization. Large emissions of CO2| other trace gases and aerosols have changed the composition of the atmosphere( This is changing the global radiation budget of the earth-atmosphere system. Investigations carried out by Intergovernmental Panel on Climate Change (IPCC) have concluded that the earth's average temperature has increased by 0.6 0.2 deg C in the 20th century. 5854,2002,2,3,Effect of global warming on the length-of-day,[1] The anthropogenic increase in greenhouse gas concentrations in the Earth atmosphere will probably induce important modifications of the global circulation in the atmosphere and ocean. Due to the angular momentum conservation of the Earth-atmosphere-ocean system| variation of the length-of-day (LOD) can be expected. By using the outputs of the models participating to the Coupled Model Intercomparison Project (CMIP-2)| we reach the following conclusions: (1) the models globally agree to an increase of the LOD of the order of 1 m mus/year| (2) the effect is mostly associated with an increase of the mean zonal wind| of which about one third is compensated by a change in mass repartition. 2900,2002,4,4,Effect of horizontal grid resolution on the near-equilibrium solution of a global ocean-sea ice model,[1] We compare the near-equilibrium solution of a global ocean/sea ice model at a horizontal grid resolution of 1degrees x 1degrees to near-equilibrium solutions obtained in two configurations at 4degrees (longitude) x 2degrees (latitude) resolution. All simulations use realistic| smoothed topography and monthly averaged climatological forcings. Our comparison of the results emphasizes large-scale features relevant to global climate change. Since neither the 1degrees x 1degrees simulation nor the 4degrees x 2degrees simulations resolves ocean eddies| our results do not address the possible importance of resolving eddies in ocean-climate simulations. There are significant differences between the 1degrees x 1degrees and 4degrees x 2degrees simulations| most notably in the Arctic Ocean. However| the large-scale features of the model solutions are very similar at the two resolutions and in many cases are more sensitive to a large difference in horizontal viscosity than to the difference in resolution. This suggests that other approaches to improving the solution of ocean-climate models will be more effective than increases in horizontal resolution outside the eddy-resolving regime. 5683,2002,3,4,Effect of N2O to C4F8/O-2 on global warming during silicon nitride plasma enhanced chemical vapor deposition (PECVD) chamber cleaning using a remote inductively coupled plasma source,For the silicon nitride plasma enhanced chemical vapor deposition (PECVD) chamber cleaning| a remote inductively coupled plasma (ICP) source was used with C4F8/O-2/N2O and the effects of N2O on the silicon nitride cleaning rates and global warming were investigated. By adding 5% of N2O to C4F8/O-2| the cleaning rate comparable to that of optimized Ar/NF3 could be obtained. At the exhaust line| CF4| C4F8| NF3| etc. were detected and the significant decrease of million metric tons of carbon equivalent (MMTCE) observed by the addition of N2O to C4F8/O-2 was due to the decrease of emitted CF4. The MMTCE for the optimized C4F8/O-2/N2O was also similar to that for Ar/NF3 at the highest cleaning condition. 5767,2002,4,3,Effect of oceanic uptake on atmospheric lifetimes of selected trace gases,We have calculated from a 2degrees x 2degrees grid of oceanic properties the contribution of oceanic loss to the overall lifetimes of a number of anthropogenic and naturally produced trace gases involved in global warming and stratospheric ozone depletion. The model| originally developed for atmospheric methyl bromide| can be used for any well-mixed trace gas where the seawater degradation rate constants and solubilities are known. Of the gases tested| it is clear that known oceanic chemical degradation processes alone are not significant sinks for most HFCs and HCFCs. Chemical degradation in the oceans is a substantial sink for COS (28%) and COCl2 (8%) and a minor sink for CH3Cl (<2%) and CH3I (2.5%)| and it should be considered when determining atmospheric lifetimes and sink strengths for these gases. Biological degradation processes are likely to increase the oceanic uptake rates of many gases. 5883,2002,3,4,Effect of solid reactant conditions on adsorption of halon decomposition gases,Carbon halides| especially halons (bromofluorocarbons)| are compounds known to deplete the ozone layer and contribute to global warming. Appropriate treatments to decompose halon waste is important to protect the environment. A dry process to decompose halon has been developed. Solid alkaline carbonate and hydrate obtained from dolomite were prepared for the reactants to decompose halon and to react with the fluorine and bromine produced by the halon decomposition. Twelve kinds of reactants were obtained by changing the burning temperature and burning time. The amount of the decomposed halon and the conversion were correlated with the pore distributions in the reactants. The distributions of F and Br differed depending on the preparation of the reactants. The difference would be attributed to the reactivity and the diffusion rate of the gases produced by the decomposing halon. 2844,2002,2,3,Effects of elevated CO2 and temperature on plant growth and herbivore defensive chemistry,Concentration of atmospheric CO2 and temperature have both been rising for the last three decades. In this century| the temperature has been predicted to rise by 2-5degreesC and the CO2 concentration to double. These changes may affect the primary and secondary metabolism of plants and thus have implications for other trophic levels. However| the biotic interactions in changing climate conditions are poorly known. In this study| two questions were addressed: W How will climate change affect growth and the amounts of secondary compounds in flexible plant species? and 60 How will this affect herbivores living on this species. Four clones of the dark-leaved willow (Salix myrsinifolia (Salisb.)) seedlings were grown in closed-top chambers with two controlled factors: concentration of atmospheric CO2 and temperature (T). There were four combinations of these factors| each combination replicated four times (total of 16 chambers): (i) Control CO2 (350 ppm) and control T| (ii) Elevated CO2 (700 ppm) and control T| (iii) Control CO2 and elevated T (2degreesC)| and (iv) Elevated CO2 and elevated T. Stem growth and aerial biomass of the plants were determined; and the leaf phenolics| nitrogen and water concentrations were analysed. In addition the growth rate of larvae and feeding preference of adults of a specialist herbivore| the chrysomelid beetle Phratora vitellinae (L.)| on the treated willow leaves were measured. Elevated temperature and CO2 concentration increased the stem biomass and elevated CO2 increased leaf biomass and total aerial biomass of the willows. Patterns of biomass allocation were different in different temperature treatments. At elevated temperature there was less branch and leaf material in relation to stems than at the control temperature. Moreover| patterns of biomass allocation differed among clones. CO2 enhancement increased the specific leaf weight (SLW) and reduced both water and nitrogen content of the leaves| however| leaf area was unaffected by the treatments. Carbon dioxide (CO2) and T enhancement reduced the concentrations of several phenolic compounds in the leaves. Phenolic compounds| nutrients| and water in the leaves might be diluted partly due to increased carbon allocation to different structures (e.g. thickening of cell wall and increase of trichomes| etc.). In some cases plant clones showed specific responses to treatments. The CO2 enhancement reduced the relative growth rate (RGR) of the beetle larvae| and in contrast| temperature elevation increased it. Adult beetles did not clearly discriminate between willow leaves grown in different T and CO2 environments| but tended to eat more leaf material from chambers with doubled CO2 concentration. At elevated CO2 adult beetles may need to eat more leaf material in order to reproduce| which may in turn prolong the life cycles| increasing the risk of being eaten and possibly affecting ability to overwinter successfully. Overall| climate change may significantly modify the dynamic interaction between willow and beetle populations. 5923,2002,2,4,Effects of increased temperatures simulating climate change on terrestrial invertebrates on Ross Island| Antarctica,Passive cloches were deployed for 27 months (three austral summers) at Cape Bird| Ross Island| Antarctica (77degrees13'S| 166degrees26'E) to investigate the response of soil invertebrates to increased temperatures. Soil surface temperatures in cloches were significantly higher than in lidless control plots or unmanipulated sites. Soil surfaces in cloche plots exceeded 0 C and 8 C (the approximate threshold for growth and development in several invertebrate species) for longer than in control plots. No consistent changes in populations of Gomphiocephalus hodgsoni (Collembola)| Stereotydeus mollis (Acari) Nanorchestes antarcticus (Acari) or observed in the cloche plots after 3 growing seasons at higher temperatures. Abundance of S. mollis was strongly related to algal biomass| but abundances of other species were not clearly related to the environmental characteristics of manipulation plots. Although low temperatures may have a role as a limiting factor on a geographical scale| local populations of invertebrates are probably influenced more by the availability of liquid water; and invertebrate responses could be very slow owing to short growing seasons and long life cycles in continental Antarctica. 2861,2002,5,4,Effects of Oligo-Miocene global climate changes on mammalian species richness in the northwestern quarter of the USA,We derived species richness curves using three different methods for mammal species recorded in fossil deposits between 30 million and 9 million years old (late Oligocene through late Miocene) for three geographic regions in the USA: the Northwest| northern Rocky Mountains and northern Great Plains. The data were used to examine the relationship between global climate change and species richness at the regional scale. Our goal was to test the hypothesis that geographic scaling issues account for the lack of correlation that has been observed between continental species richness and the oxygen-isotope curve. The results of all three methods used in this study suggest that species richness in the three regions analysed did not change in response to the global temperature signal| supporting the inferences drawn from continental-scale analyses. The most prominent signal is a peak in species richness in the Rocky Mountain region about 15 million years ago| possibly due to increased beta diversity within the mountains| although many of these species were shared between all three biogeographic provinces. This peak coincides with the Mid-Miocene Climatic Optimum| but it appears unlikely that global temperature change was the direct cause because no response in species richness characterized the even greater Late Oligocene Warming. The Mid-Miocene richness peak also closely follows the onset of major tectonic events in the Rocky Mountain region| which may have led to increased within-province endemism through a combination of physiographic and related climatic effects not recorded in the global temperature signal| a hypothesis that deserves detailed testing. 5794,2002,2,4,Effects of temperature and oxygen availability on greenhouse gas and nutrient dynamics in sediment of a eutrophic mid-boreal lake,The effects of oxygen conditions and temperature on dynamics of greenhouse gases (CH4| CO2| N2O) and nutrients (NH4+| NO2-+NO3-|-| tot-P) were studied in sediment of hyper-eutrophic Lake Kevaton| Finland. Undisturbed sediment cores were incubated at 6| 11| 16| and 23 degreesC in a laboratory microcosm using a continuous water flow technique with an oxic or anoxic water flow. The production of CO2 increased with increasing temperature in both oxic (Q(10) 3.2 +/- 0.6) and anoxic (Q(10) 2.3 +/- 0.4) flows. The release of CH4 increased with temperature in anoxic conditions (Q(10) 2.3 +/- 0.2)| but was negligible with the oxic flow at all temperatures. The release of NH4+ increased with temperature with the oxic and anoxic flows (Q(10) 2.4 +/- 0.1). There was a net production of NO2-| NO3- and N2O with the oxic flow at temperatures below 16 degreesC. The release of phosphorus was greater from the anoxic sediments and increased with temperature with both the anoxic (Q(10) 2.9 +/- 0.5) and oxic (Q(10) 1.9 +/- 0.1) flows. It is probable that the temperature of boreal lakes and the associated oxygen deficiency will increase as the climate becomes warmer. Our experiments showed that this change would increase the global warming potential of greenhouse gases released from sediments of eutrophic lakes predominately attributable to the increase in the CH4 production. Furthermore| warming would also accelerate the eutrophication of lakes by increasing release of phosphorus and mineral nitrogen from sediments| which further enhance CH4 production in sediments. 5919,2002,4,3,Electrochemical or photocatalytic reduction of carbon dioxide released to the environment and atomic spectrometry for environmental sample analysis,CO2 causes the greenhouse effect and consequent natural disruption of the environment. Therefore| it| needs to develop technologies for the sequestration and reduction of CO2. On the other hand| some diseases with the chronic intake of metals at low concentration will possibly become a problem in the future| which means that it is required to develop accurate analytical methods for metals at even lower concentration. Based on these circumstances| the electrochemical or photocatalytic reduction of CO2. released to the environment| and atomic spectrometry for environmental samples were investigated. First| in the electrochemical reduction of CO2 in methanol| the reduction products could be controlled| by the selections of supporting electrolytes and cathode materials. Furthermore| the photocatalytic CO2 reduction reaction could proceed in liquid and supercritical CO2 media. Next| a sensitive and accurate analytical method of specific trace metals| such as cobalt| silver and rhodium| in environmental samples by electrothermal atomization atomic absorption spectrometry with a metal tube atomizer was developed. Moreover| a direct determination method of elemental content in individual dried biological cells and particulates by ICP-AES or ICP-MS was investigated. These determination methods may play a significant role in various fields| such as environmental science| pharmacy and biochemistry. 5866,2002,3,3,Emission of carbon dioxide from soil,Carbon dioxide (CO2) is an important greenhouse gas accounting for 60% of the total greenhouse effect. Soil is a major source for atmospheric CO2. In the event of growing threats of global warming due to greenhouse gas emissions| reducing CO2 emission by sequestering C in the soil is of prime importance. Soil management practices like increasing soil organic carbon content| reduced tillage| manuring| residue incorporation| improving soil biodiversity| micro-aggregation and mulching can play an important role in sequestering C in soil. 5835,2002,3,2,Emissions and environmental impacts from air-conditioning and refrigeration systems,The impacts of air conditioning and refrigeration systems on stratospheric ozone are primarily linked to release of ozone-depleting refrigerants. Their contributions to global warming stem both from release of refrigerants and from emission of greenhouse gases (GHGs) for associated energy use. Because the energy-related component has a significantly higher warming impact| phaseout of hydrofluorocarbon (HFC) refrigerants with less efficient options will increase net GHG emissions. The same conclusion applies for perfluorocarbon (PFCs)| though they are less commonly used as refrigerants. Integrated assessment of ozone depletion| global warming| and atmospheric lifetime provides essential indications in the absence of ideal refrigerants| namely those free of these problems as well as safety| stability| compatibility| cost| and similar burdens. This study examines the trend in refrigerant losses from chiller use. It documents both substantial progress in release reductions and the technical innovations to achieve them. It contrasts the impacts of current refrigerants with alternatives and with the chlorofluorocarbons (CFCs) they replaced. The study examines the sensitivity of efficiency to charge loss. It also summarizes thermodynamic and environmental comparisons of options to show that phaseout decisions based on chemical composition alone| without regard to attributes of individual substances| can result in greater environmental harm than benefit. (C) 2002 Elsevier Science Ltd and IIR. All rights reserved. 5684,2002,3,4,Emissions trading: Seeking a solution to global warming,The article reports on the results of an analysis of the greenhouse gas emissions (GHG) reporting practices at top companies in "Chemical Week's" 2009 Billion Dollar Club which reveal that a wide variety of reporting practices and varying results. It notes that many companies do not report GHG emissions| which include Dow Chemical and DuPont. Data used in the analysis were from reports to the Carbon Disclosure Project| a voluntary GHG reporting initiative. It found that emissions vary across industry sectors on a per-sales basis.
5944,2002,2,4,Endemism| rarity and vulnerability of marine species along a temperate coastline,The marine decapod| echinoderm and mollusc fauna from the State of Victoria| Australia| was systematically assessed for species that are potentially vulnerable to extinction. Species were identified that are short-range endemics| restricted to isolated populations| restricted to vulnerable habitats| or vulnerable to a rise in sea temperature from global warming. Of the 1650 species assessed| 3.7% were potentially endemic to Victoria| although many of these were known from few records and their described distribution may reflect collection or taxonomic artefacts. More species were restricted to vulnerable habitats: 0.7% to seagrass beds; 3% to embayments; 3.5% to the trawled area of continental shelf off east Gippsland; and 6% to the intertidal/shallow subtidal zone (03 m). Up to 14% of species are confined to the cool temperate waters of south-eastern Australia and could become locally extinct within Victoria from a sea temperature rise of 1-2degreesC. The potential for biodiversity loss from Victorian marine waters is discussed. 5874,2002,3,4,Energy| industry and nitrogen: Strategies for decreasing reactive nitrogen emissions,Nitrogen oxides are released during atmospheric combustion of fossil fuels and biomass| and during the production of certain chemicals and products. They can react with natural or man-made volatile organic compounds to produce smog| or else can be further oxidized to produce particulate haze| or acid rain that can eutrophy land and water. The reactive nitrogen that begins in the energy sector thus cascades through the atmosphere| the hydrosphere and soils before being eventually partially denitrifed to the global warming and stratospheric ozone-depleting gas nitrous oxide or molecular nitrogen. This paper will suggest how an economic analysis of the nitrogen cycle can identify the most cost-effective places to intervene. Nitrogen oxides released during fossil-fuel combustion in vehicles| power plants and heating boilers can either be controlled by add-on emission control technology| or can be eliminated by many of the same technical options that lead to carbon dioxide reduction. These integrated strategies also address sustainability| economic development and national security issues. Similarly in industrial production| it is more effective to focus on redesigning industrial processes rather than on nitrogen oxide pollution elimination from the current system. This paper will suggest which strategies might be utilized to address multiple benefits rather than focusing on single pollutants.
5735,2002,2,4,ENSO and cholera: A nonstationary link related to climate change?,We present here quantitative evidence for an increased role of interannual climate variability on the temporal dynamics of an infectious disease. The evidence is based on time-series analyses of the relationship between El Nino/Southern Oscillation (ENSO) and cholera prevalence in Bangladesh (formerly Bengal) during two different time periods. A strong and consistent signature of ENSO is apparent in the last two decades (1980-2001)| while it is weaker and eventually uncorrelated during the first parts of the last century (1893-1920 and 1920-1940| respectively). Concomitant with these changes| the Southern Oscillation Index (SOI) undergoes shifts in its frequency spectrum. These changes include an intensification of the approximately 4-yr cycle during the recent interval as a response to the well documented Pacific basin regime shift of 1976. This change in remote ENSO modulation alone can only partially serve to substantiate the differences observed in cholera. Regional or basin-wide changes possibly linked to global warming must be invoked that seem to facilitate ENSO transmission. For the recent cholera series and during specific time intervals corresponding to local maxima in ENSO| this climate phenomenon accounts for over 70% of disease variance. This strong association is discontinuous in time and can only be captured with a technique designed to isolate transient couplings. 5842,2002,2,4,Environmental refugees: a growing phenomenon of the 21st century,There is a new phenomenon in the global arena: environmental refugees. These are people who can no longer gain a secure livelihood in their homelands because of drought| soil erosion| desertification| deforestation and other environmental problems| together with the associated problems of population pressures and profound poverty. In their desperation| these people feel they have no alternative but to seek sanctuary elsewhere| however hazardous the attempt. Not all of them have Red their countries| many being internally displaced. But all have abandoned their homelands on a semi-permanent if not permanent basis| with little hope of a foreseeable return. In 1995| environmental refugees totalled at least 25 million people| compared with 27 million traditional refugees (people fleeing political oppression| religious persecution and ethnic troubles). The total number of environmental refugees could well double by the year 2010| and increase steadily for a good while thereafter as growing numbers of impoverished people press ever harder on overloaded environments. When global warming takes hold| there could be as many as 200 million people overtaken by sea-level rise and coastal flooding| by disruptions of monsoon systems and other rainfall regimes| and by droughts of unprecedented severity and duration. 2883,2002,2,4,Estimated biomass and productivity of natural vegetation on the Tibetan Plateau,We developed a methodology for linking together data from forest and grassland inventories and ecological research sites| and provided a comprehensive report about live biomass and net primary productivity (NPP) on the Tibetan Plateau| the "Third Pole" of the earth where little information about plant biomass and production had been available outside China. Results were as follows. (1) The total live biomass of the natural vegetation in the Xizang (Tibet) Autonomous Region and Qinghai Province was estimated its 2|17 Gg dry mass| of which 72.9% was stored in forests where spruce-fir accounted for 65.1% (2) The total annual NPP of the natural vegetation in these two administrative regions| was estimated as 0.57 Gg dry mass. of which grasslands and forests accounted for 69.5% and 18.1%| respectively. (3) The alpine spruce-fir forests of the Tibetan Plateau had the highest maximum live biomass of the spruce-fir forests globally. with values up to 500-1600 Mg DM/ha (including both aboveground and belowground biomass)| (4) The QZNPP model generally predicted NPP well for most of the biomes on the plateau| and simulated the various Chinese vegetation divisions. Model results showed a positive reinforcing effect of monsoon climate in China where the warmest season coincides with the wettest season. (5) The live biomass map for 117 counties of Xizang (Tibet) and Qinghai and the Potential NPP map for the whole plateau both showed the same decreasing trend from Southeast to northwest. 2891,2002,2,3,Estimated migration rates under scenarios of global climate change,Aim Greenhouse-induced warming and resulting shifts in climatic zones may exceed the migration capabilities of some species. We used fourteen combinations of General Circulation Models (GCMs) and Global Vegetation Models (GVMs) to investigate possible migration rates required under CO(2) -doubled climatic forcing. Location Global. Methods Migration distances were calculated between grid cells of future biome type x and nearest same-biome-type cells in the current climate. In 'base-case' calculations| we assumed that 2 x CO(2) climate forcing would occur in 100 years| we used ten biome types and we measured migration distances as straight-line distances ignoring water barriers and human development. In sensitivity analyses| we investigated different time periods of 2 x CO(2) climate forcing| more narrowly defined biomes and barriers because of water bodies and human development. Results In the base-case calculations| average migration rates varied significantly according to the GVM used (BIOME3 vs. MAPSS)| the age of the GCM (older- vs. newer-generation GCMs)| and whether or not GCMs included sulphate cooling or CO(2) fertilization effects. However| high migration rates (greater than or equal to 1000 m year(-1)) were relatively common in all models| consisting on average of 17% grid cells for BIOME3 and 21% for MAPSS. Migration rates were much higher in boreal and temperate biomes than in tropical biomes. Doubling of the time period of 2 x CO(2) forcing reduced these areas of high migration rates to c . 12% of grid cells for both BIOME3 and MAPSS. However| to obtain migration rates in the Boreal biome that were similar in magnitude to those observed for spruce when it followed the retreating North American Glacier| a radical increase in the period of warming was required| from 100 to >1000 years. A reduction in biome area by an order of magnitude increased migration rates by one to three orders of magnitude| depending on the GVM. Large water bodies and human development had regionally important effects in increasing migration rates. Main conclusions In conclusion| evidence from coupled GCMs and GVMs suggests that global warming may require migration rates much faster than those observed during post-glacial times and hence has the potential to reduce biodiversity by selecting for highly mobile and opportunistic species. Several poorly understood factors that are expected to influence the magnitude of any such reduction are discussed| including intrinsic migrational capabilities| barriers to migration| the role of outlier populations in increasing migration rates| the role of climate in setting range limits and variation in species range sizes. 5814,2002,2,4,Estimations of the past groundwater recharge rate from deep borehole temperature data,order to estimate the past groundwater recharge rates from deep borehole temperature data| observed temperature-depth profiles are compared with the profiles calculated from heat conduction-convection equation under the condition of linear increase in surface temperature due to global warming and urbanization in Tokyo metropolitan area. The results show the increase in groundwater recharge rate from the 1890s to 1940s| and it decreased from the 1940s to 1990s. These estimations agree well with the precipitation record in Tokyo during the last 100 years. Therefore| the deep borehole temperature data can be used for estimating not only surface temperature history but also the past groundwater recharge rate in Tokyo area. (C) 2002 Elsevier Science B.V. All rights reserved. 5765,2002,2,4,Evaluating genetic resources of forest trees by means of life history traits - a Norwegian example,Additive variation in adaptive traits is a prerequisite for selection and adaptation to future environmental changes| but distribution of adaptive genetic variability between and within populations is poorly known in most forest trees. Owing to this deficiency| life history traits such as geographic range| pollination vector and seed dispersal capability| which significantly affect gene flow and thus the distribution of genetic variability| were used to evaluate the genetic resources in 23 Norwegian native forest tree species. Based on the combination of life history traits the species' genetic resources were classified either as viable| potentially vulnerable or vulnerable| assuming a decrease in within-population variability in this sequence. Twelve widely distributed species with generally effective dispersal of pollen and seeds were considered viable (Pinus sylvestris| Picea abies| Juniperus communis| Betula pubescens| B. pendula| Alnus incana| A. glutinosa| Salix caprea| Populus tremula| Corylus avellana| Sorbus aucuparia| Prunus padus) and have as such no particular conservation needs. Effective seed dispersal of these species| as inferred from post-glacial migration rates| may be partly responsible for their generally early post-glacial appearance| and may| in combination with the wide ranges and relatively large evolutionary potential| indicate that viable species are best able to cope with climatic change. Among species with restricted ranges and more limited gene flow eight were considered potentially vulnerable (Quercus petraea| Q. robur| Fraxinus excelsior| Acer platanoides| Taxus baccata| Ilex aquifolium| Fagus sylvatica| Ulmus glabra) and three were considered vulnerable (Tilia cordata| Malus sylvestris| P. avium). Application of different intensities of a multiple population breeding system (MPBS) is considered the most appropriate mode of conserving genetic resources in these species. 2893,2002,3,4,Evaluating sustainable energy strategies for a water utility,Research suggests that political will to deliver improvements in the quality of surface water in the UK and across the EU| alongside measures to place tighter controls on the quality of biosolids applied to agricultural land| will augment the levels of energy used in sewage and sludge treatment. This coincides with increasing concerns over the use of fossil fuel derived energy sources and their potential to enhance the Earth's greenhouse effect and promote global climate change| creating a serious paradox for those responsible for managing the aquatic environment. However| previous research also suggests that novel technologies and practices could potentially mitigate the problem in hand. This paper describes the development of a model for estimating future energy use and CO2 emissions in the wastewater treatment sector| and outlines the results of different projections using incumbent and novel practices. Indications are that using incumbent approaches could augment CO2 emissions by 15-30% in the medium- to long-term| while loss of the agricultural sludge route and deployment of an incineration strategy could mean increases are of the order of 50-70%. Alternatively| the construction of a greater number of sludge treatment facilities| with greater biogas recovery| could reduce this burden to around -8 to +7% over the same period| while the realisation of the full potential an anaerobic pre-treatment process could lead to reductions of up to 16%. Nevertheless| some of the options will come at a higher cost then incumbents| and the potential for making the business case for these investments is explored. 5718,2002,2,4,Evaluation of limnological responses to recent environmental change and caribou activity in the Riviere George Region| northern Quebec| Canada,The influence of natural terrestrial disturbances on the limnology of northern lakes is little known| yet important for understanding the ecology of these remote ecosystems. The Riviere George Caribou Herd (RGCH) in northern Quebec has undergone a large population increase since the 1950s| which has been accompanied by pronounced impacts (i.e.| degradation of vegetation cover| soil erosion) on terrestrial environments of the Riviere George region. The goal of our study was to evaluate if the increased caribou activity and resulting terrestrial impacts have been accompanied by impacts on adjacent aquatic ecosystems. We studied the recent diatom assemblages (i.e.| about the last two centuries) preserved in six sediment cores taken from lakes located in the most heavily impacted region| and in one core from a lake showing little evidence of recent caribou activity in the catchment basin. Core chronologies based on Pb-210 dating techniques indicated that average mass sedimentation rates in this subarctic region were very low (0.0039 to 0.012 g cm(-2) yr(-1)). Perhaps surprisingly| diatom assemblages from all seven cores showed very little change| indicating remarkably stable limnological conditions throughout the past similar to200 yr. The lack of a signal from caribou activity is most likely due to (1) short-term impacts being too transitory to be registered in the sediment record| and (2) long-term impacts not representing a significant perturbation outside the natural variability of these aquatic ecosystems. In contrast to other arctic regions| the limnological stability of our study sites suggests that recent climatic change impacts have been negligible in this region of northern Quebec| which seems to confirm climate model predictions that northern Quebec and Labrador will remain climatically stable under global warming scenarios. 5710,2002,3,3,Evaluation of the environmental implications to include structural changes in a wastewater treatment plant,The environmental implications of including structural changes in a wastewater treatment plant to decrease effluent concentrations of nitrogen were evaluated in this study. Environmental effects from these structural changes were assessed by using the Life Cycle Assessment theoretical framework. The wastewater treatment plant selected as a reference scenario had an activated sludge configuration. The Ludzack-Ettinger and Oxidation Ditch configurations were selected as modifications of the reference scenario. Results from this study show that the inclusion of nitrogen removal mechanisms in the configuration of the plant reduces the effect of the plant on the eutrophication| but simultaneously increases the effect on the consumption of abiotic resources| global warming| acidification and human toxicity. These general trends| however| vary depending on the configuration selected to remove nitrogen. Taking all the impacts together| the Oxidation Ditch configuration would cause less environmental impact than the Ludzack-Ettinger configuration| given the characteristics of the selected scenarios. (C) 2002 Society of Chemical Industry. 5841,2002,4,4,Evaporative climate changes at Bet Dagan| Israel| 1964-1998,Analysis of evaporation measurements made between 1964 and 1998 at Bet Dagan in Israel's central coastal plain shows a small but statistically significant increase in screened Class A pan evaporation| mainly in the dry| summer half of the year. No changes were found in the total open water evaporation or reference crop evapotranspiraton estimated with Penman's combined heat balance and aerodynamic equation because the decreases found in the radiation balance term were offset by increases in the aerodynamic term. The climatic changes responsible for these opposing trends were| respectively| decreases in global irradiance and increases in water vapor pressure deficit (VPD) and wind speed| the latter associated with changes in wind direction. Increases in windspeed were found to be concentrated in afternoon hours of summer and fall months| while those of VPD were in the late afternoon of fall months. Possible reasons for these changes are discussed. Normalized pan evaporation for dry months showed no significant time trend| but a significant increase was found for wet months. These results support the view that the widespread reductions in potential evaporation that have been reported| although not found at Bet Dagan| were caused by global dimming rather than an increase in the rate of atmospheric moisture cycling due to global warming. (C) 2002 Elsevier Science B.V. All rights reserved. 5822,2002,2,4,Evidence for a persistent and extensive greening trend in Eurasia inferred from satellite vegetation index data,[1] The northern latitudes have warmed by similar to0.8degreesC since the early 1970s| but not all areas have warmed equally. Eurasia shows an overall warming trend| while North America exhibits warming at a lower rate and even a slight cooling trend during the last 50 years in the eastern United States. We analyzed a recently developed satellite normalized difference vegetation index (NDVI) data set (July 1981 to December 1999) to assess vegetation response to these temperature changes. An index of persistence of the NDVI trend was used to generate patches of different levels of persistence. The persistence data were analyzed for patch area| patch perimeter| patch number| patch coherence| largest patch size| patch fragmentation| pixel contiguity| pixel clustering| and conditional probability of pixel adjacency. We address two questions: (1) Is there a difference in the spatial pattern of long-term NDVI increase in comparison to short-term increase? and (2) Are there differences in the spatial patterns of patches between Eurasia and North America? The results indicate a persistent and spatially extensive and connected greening trend in Eurasia| relative to North America. The regions showing short-term greening in Eurasia show a scattered pattern of spatially remote small patches. In North America the long-term greening pattern is spatially fragmented| and a mixture of short-and long-term NDVI increase is found| unlike in Eurasia. Therefore we conclude that the greening trend in Eurasia is more persistent and spatially extensive than in North America| which is qualitatively consistent with near-surface air temperature observations. 5878,2002,5,4,Evidence of surface water oligotrophy during the Paleocene-Eocene thermal maximum: Nannofossil assemblage data from Ocean Drilling Program Site 690| Maud Rise| Weddell Sea,[1] Nannoplankton assemblages at Ocean Drilling Program Site 690 (Maud Rise| Weddell Sea) experienced an abrupt and dramatic transformation at the onset of the Paleocene-Eocene Thermal Maximum (PETM) at similar to55 m.y. The major assemblage shift suggests a change from colder| more productive surface waters to warmer| more oligotrophic conditions. Significant restructuring of assemblages during the later part of the PETM indicates that nannoplankton communities were not stable and that surface water conditions changed| although they remained warm and oligotrophic. Combined with benthic foraminiferal assemblage data| nannoplankton assemblage results suggest increased sequestration of nutrients in shelf environments and starvation of the open ocean. Although the PETM was a short-lived event| it appears to have had long-term effects on nannoplankton| leading to the extinction of Fasciculithus| a dominant Paleocene genus. 5809,2002,4,4,Evidence of the present relative land stability of Venice| Italy| from land| sea| and space observations,[1] The city of Venice is very vulnerable to loss in surface elevation as a result of subsidence and eustacy because of its small elevation above sea level. The alarm of the scientific community related to this persistent problem is increasing because of the forecasts of sea level rise caused by global warming. In order to evaluate the present relative subsidence of Venice| a study has been performed by combining high precision leveling| Satellite Radar Interferometry (SRI) and tide gauge measurements. The analysis of the most recent data points out with an unprecedented detail the present ground stability of the city. 2853,2002,5,4,Evolution of heat transport pathways in the Indonesian Archipelago during last deglaciation,The Indonesian Archipelago provides important heat transport pathways of the Western Pacific Warm Pool between the northern Indian Ocean and western equatorial Pacific Ocean| that exert important impacts on global climate change. This study investigated AMS C-14| delta(18)O| planktonic foraminifer assemblages and sedimentation rates in three piston cores collected in the Indonesian Archipelago. The results indicate that changes in the Indonesian Archipelago heat transport pathways were phase characteristic and in steps during the last deglaciation. In the deglaciation Termination IA| at about 12.5 kaBP| sea level rose rapidly in a short time period| and Makassar and Lombok straits widened suddenly for warm and fresh water from the Pacific to pour into the Java Sea and eastern Indian Ocean. During the Termination IB| about 9.5 kaBP| sea level rose rapidly again| and the South China Sea (SCS) started to connect with the Java Sea. With monsoon actions| a large amount of fresh water from the SCS shelf area flew through the Indonesian Archipelago. 5806,2002,2,4,Evolution of insect-plant relationships: chemical constraints| coadaptation| and concordance of insect/plant traits,Co-adaptations| co-evolution| and co-speciation between herbivores and their host plants have been topics of interest for several decades. Difficulties in deciphering these relationships as well as physiological| biochemical| and ecological adaptations of herbivorous insects themselves are discussed here in relation to biotic and abiotic environmental factors that create temporal as well as spatial mosaics of genetic variation. Hybridization was shown in swallowtail butterflies (Papilio) (Lepidoptera: Papilionidae) to produce some trait concordance| but mostly independent geographic trait clines (physiological| biochemical| and morphological). Strong and extensive genetic introgression of Liriodendron tulipifera detoxification abilities was documented northward across the hybrid zone| presumably as a result of regional climate warming only during the last 3-4 years. These and other genetic novelties produced by hybridization may be important in speciation processes| and they also emphasize the difficulties identifying appropriate taxonomic classifications for discussing any species concept. Host plant detoxification abilities (as 'key innovations') are shown capable of rapid movement between different polyphagous herbivore species independently of the host plant availability and well beyond the insect species geographical range distribution. Part of the difficulty associated with ecologically categorizing herbivore species and identifying affiliated adaptations for host plant use may be related to independent movement of various 'species-diagnostic' traits. Climate-driven local selection regimes could help generate the dynamic variation observed for co-adapted| co-evolved| or non-adapted genotypes| and may produce the confusing and changing patterns of geographic mosaics seen within and among closely related herbivores. Experimental analyses of several factors that could explain the asymmetrical shapes of trait clines across the hybrid zone for tiger swallowtail butterflies are discussed. 2903,2002,4,4,Evolution of the organization for tropical studies,The Organization for Tropical Studies (OTS)/Organizacion para Estudios Tropicales (OET) has evolved in many ways since its founding in 1963 as a non-profit consortium offering graduate courses and facilitating research in tropical ecology in Costa Rica. By 2002| its international membership included about 65 institutions| including four from Costa Rica. It had developed three Costa Rican field stations (La Selva| Las Cruces| and Palo Verde) with excellent facilities for teaching and research| and it was constructing a new Costa Rican office at the University of Costa Rica. Combinations of internal and external pressures influenced OTS to develop in new directions in the 1980s and 1990s. It became more diversified and more concerned with applied science in its traditional areas of graduate education and research facilitation. The Organization also evolved into new niches: more applied biology| professional education| environmental education and policy| conservation efforts| and an expanded geographic distribution to other Latin American countries. OTS was composed of changing combinations of people (Boards| members| staff) with evolving and competing priorities for limited financial resources. External environmental changes also shaped OTS's evolution. New problems of increased tropical deforestation| the emergence of the biodiversity "crisis" and conservation biology| global climate change| and calls for sustainable development affected OTS constituents and funding priorities of governments and foundations. Both internal and external pressures have in some cases demanded for OTS to improve its relationship with: Costa Rican biologists and their institutions| the Costa Rican government| and Costa Ricans living around the three OTS field stations. 2928,2002,2,4,Evolutionary genetics of mangroves: continental drift to recent climate change,Recent advances in our knowledge of the genetic architecture of mangrove species are reviewed and the consequences of this genetic architecture for species response to environmental change are inferred. The origins of mangrove taxa have been discussed many times| particularly in the context of centers of origin and continental drift. While global patterns of mangrove species diversity have been interpreted in the context of tectonic events and opening and closing of seawater passages| species evolution on a finer scale depends on more recent processes of population extinction and advances in response to spatio-temporal climatic and environmental flux. Understanding the likely effects of global climate change on mangrove distributions requires a focus on these more recent intraspecific evolutionary processes. Many mangrove taxa have wide geographic ranges that have been attributed to efficient propagule dispersal. Such gene flow should provide a genetic cohesiveness among populations. However| as with many wide-ranging marine organisms| we are finding important population genetic structure in widespread mangrove species| suggesting that gene flow is less effective than previously thought. Are these widespread taxa more recent and undergoing speciation? Spatial patterns in genetically adaptive traits indicate that some populations may survive more successfully under changing environmental conditions. However| is the present-day genetic architecture best poised to respond to predictions of climate change? These questions are addressed in the light of our increasing knowledge of genetic diversity in mangrove species. 5851,2002,2,4,Evolutionary speed of species invasions,Successful invasion may depend of the capacity of a species to adjust genetically to a spatially varying environment. This research modeled a species invasion by examining the interaction between a quantitative genetic trait and population density. It assumed: (1) a quantitative genetic trait describes the adaptation of an individual to its local ecological conditions; (2) populations far from the local optimum grow more slowly than those near the optimum; and (3) the evolution of a trait depends on local population density| because differences in local population densities cause asymmetrical gene flow. This genetics-density interaction determined the propagation speed of populations. Numerical simulations showed that populations spread by advancing as two synchronic traveling waves| one for population density and one for trait adaptation. The form of the density wave was a step front that advances homogenizing populations at their carrying capacity; the adaptation wave was a curve with finite slope that homogenizes populations at full adaptation. The largest speed of population expansion| for a dimensionless analysis| corresponded to an almost homogeneous spatial environment when this model approached an ecological description such as the Fisher-Skellam's model. A large genetic response also favored faster speeds. Evolutionary speeds| in a natural scale| showed a wide range of rates that were also slower compared to models that only consider demographics. This evolutionary speed increased with high heritability| strong stabilizing selection| and high intrinsic growth rate. It decreased for steeper environmental gradients. Also indicated was an optimal dispersal rate over which evolutionary speed declined. This is expected because dispersal moves individuals further| but homogenizes populations genetically| making them maladapted. The evolutionary speed was compared to observed data. Furthermore| a moderate increase in the sped of expansion was predicted for ecological changes related to global warming. 2945,2002,2,4,Expected threats of global climate change on mosquito and tick-borne arbovirus infections of human beings,Global warming [+ 0|5 - 0|6degrees C during the second half of the 20 th century] seems a reality although climatologists did not reach a common agreement on its actual origin| and this phenomenon may still increase along the 21 th century [+ 1|5 to 6degrees C]. Epidemiologists are anxious at the eventual effects of the resulting climate change on the evolution of arbovirus infections transmitted to human beings by hematophagous vectors such as mosquitoes and ticks. Analysis of the literature devoted to this problem did not lead to precise conclusions and the mathematical models used seems insufficient for they take into account mainly the climatic factors and not enough the human ones. Examples of dengue| european tick-borne encephalitis and other arbovirus infections are discussed. Peculiar attention is devoted to the eventual effects of climatic changes on the hibernation process in some small mammals and the dining of bird's migrations| involved in enzootic cycles of arboviruses. It is likely| that arbovirus diseases may locally extend| both in latitude and altitude| leading to outbreaks| but regressions may also occur. 5716,2002,2,4,Factors controlling species richness in alpine plant communities: An assessment of the importance of stress and disturbance,This study explores whether the high variability of vascular plant diversity among alpine plant communities can be explained by stress and/or disturbance intensities. Species numbers of 14 alpine plant communities were sampled in the Swiss Alps. To quantify the intensity of 13 stress and 6 disturbance factors potentially controlling plant life in these communities| a survey was conducted by asking numerous specialists in alpine vegetation to assess the importance of the different factors for each community. The estimated values were combined in stress- and disturbance-indices which were compared with diversity according to the Intermediate Stress Hypothesis| the Intermediate Disturbance Hypothesis| and the Dynamic Equilibrium Model| respectively. Each of these theories explained a part of the variability in the species richness| but only the Dynamic Equilibrium Model provided a complete and consistent explanation. The last model suggests that community species richness within the alpine life zone is generally controlled by stress intensity. Disturbance and competition seem to play a secondary role by fine-tuning diversity in specific communities. As diversity is primarily limited by stress| a moderation of temperature-related stress factors| as a result of global warming| may cause a shift of the equilibrium between stress| disturbance| and competition in alpine ecosystems. 5739,2002,3,4,Feasible suppression technique of methane emission from paddy soil by iron amendment,A revolving furnace slag (RFS)| which is a by-product of the steel industry| and a spent disposable portable body warmer (PBW)| which harnessed the heat of iron oxidation reaction| were used as iron materials. Portions of 4 kg of Coarse and Medium Textured Gley soil were placed into plastic pots (3 L). RFS was added to the pots at the rate of 0 (control)| 10| 20| 40| 100 ton ha(-1)| while PBW was added at 10 ton ha(-1) only. Methane flux from the potted soil with rice plants and Eh were measured during cropping seasons in 1999 and 2000. In the 1999 experiment| the RFS treatments showed lower Eh values compared with the control| especially at the early period of cultivation| although the RFS was applied to maintain the soil oxidative. The rapid decrease in Eh under high application of RFS may be due to the high pH of the RFS (pH (RFS: H2O = 1: 2.5) was 12.2). However| total methane emission during the cultivation period significantly decreased| about 10%| when 10-40 ton ha(-1) of RFS and 10 ton ha(-1) of PBW were applied. The grain yield was significantly increased| about 30%| when 40 or 100 ton ha(-1) of RFS was applied. This was also partly due to the release of inorganic nutrients from RFS and also from soil. The latter| due to effect of the alkaline RFS on soil. In the 2000 experiment| the pots with soils from 1999 were used without further application of iron materials. The influence of high application of RFS on soil Eh disappeared| compared with 1999. Total methane emission significantly decreased| about 35%| at 20 ton ha(-1) of RFS. However| the increase of grain yield caused by RFS in 1999 was diminished| compared with 1999. Production activity of both methane and carbon dioxide at the RFS treatments were decreased| while methane oxidizing activity was increased. The decrease in total methane emission may be attributed to not only inhibition of methane production but also enhanced methane oxidation. In conclusion| methane emission from paddy soil could be suppressed| over two cropping seasons by single application of RFS without loosing grain yield. 5715,2002,2,4,Fingerprinting soil organic matter in the arctic to help predict CO2 flux,In the past 30 years| the arctic climate has warmed appreciably and there is evidence for a significant polar amplification of global warming in the future. A warming and drying of northern soils could result in an increase in organic matter decomposition and positive feedback to future climate warming. Northern ecosystems have accumulated 25-33% of the world's soil carbon| much of which is preserved as poorly decomposed plant remains. The soil organic matter (SOM) decomposition rate| however| depends on many variables such as temperature| nutrient availability| pH| oxidation/reduction potential| and chemical composition of the SOM. This paper addresses the effect of SOM composition on CO2 respiration in arctic soil. In order to isolate the effect of SOM composition on respiration rate| 19 soils from the circumpolar arctic were incubated in a 25 degreesC| nutrient-rich| pH neutral| constantly mixed environment. The SOM composition was studied using pyrolysis-gas chromatography/mass spectrometry (py-GC/MS)| an analytical technique that produces a "fingerprint" of SOM. Correlations were made between SOM composition and CO2 respiration rate for the 19 soils. From these data| a model was built to predict respiration rates in soil subjected to similar incubation conditions using py-GC/MS fingerprints. Results go on to compare model predictions of measured respiration in laboratory incubations of 15 soils from four different locations in the Northern and Western Alaska Transects. Predictions for cumulative respiration over a 70-day laboratory respiration test were within 20% of measured values. (C) 2002 Elsevier Science B.V. All rights reserved. 5887,2002,2,4,Floodwater use and management strategies in valleys of southeast Spain,Southeast Spain has a semiarid climate with highly variable rainfall from year to year. Global warming scenarios predict a decrease in rainfall in future and land-use changes may also alter run-off regimes. Water deficit has meant that various practices of floodwater farming have traditionally operated in valley floors. However| flash floods in the valley floors can also be dangerous and damaging. Many of the boqueras and other floodwater irrigation systems have been abandoned. The effects on the hydrological regime of the channel are calculated. These structures and water management practices could have an effect on the magnitude of low-moderate peak discharges| but are insignificant in high flows. Modem channel and flood management employs check dams| but these are frequently destroyed in moderate-high flows. Alternative strategies of channel management need to be sought and the use or vegetation cover to dissipate flood peaks and to reduce erosion may offer one possibility. Copyright (C) 2002 John Wiley Sons| Ltd. 5687,2002,2,4,Foodborne disease in the new millennium: out of the frying pan and into the fire?,About four million cases of foodborne infectious disease occur annually in Australia; new foodborne pathogens| such as enterohaemorrhagic Escherichia coli| are emerging. Climate change| combined with changes in how we produce and distribute food and how we behave as consumers| have the potential to affect foodborne disease in the coming century. Foodborne disease outbreaks are now more far-reaching (and sometimes global) due to modern mass food production and widespread food distribution. There are strong seasonal patterns for Salmonella and Campylobacter infection in Australia. Global warming may increase the incidence of infections| such as salmonellosis| and diseases caused by toxins| such as ciguatera. 2918,2002,4,4,Forcing of the quasi-biennial oscillation from a broad spectrum of atmospheric waves,[1] The circulation of the stratosphere| and its influence on the trace constituent distribution| is an important component of the climate system| which must be included in simulations of global climate change. However| the ability to simulate a dominant stratospheric phenomenon| the Quasi-Biennial Oscillation (QBO) in equatorial zonal wind| is an outstanding challenge in climate modeling. Although confined to the tropics| the QBO affects the circulation and the interannual variability of the entire stratosphere| parts of the mesosphere and possibly also of the troposphere. Here we show that the QBO is successfully simulated in a general circulation model (GCM) of the newest generation. Key factors are a sufficient spatial resolution| a realistic simulation of tropical convection| and the consideration of the effects of gravity waves. From this simulation it is inferred that a broad spectrum of atmospheric waves is necessary to generate the QBO in the model. 2871,2002,2,4,Forest tree and fern species as indicators of an unnatural fire event in a southern Cape mountain forest,fromontane forests in the southern Cape are typically surrounded by fire prone fynbos. Although the impact of fire on fynbos has been extensively studied| little is known about the impact of fire on adjacent forest. Fire swept through a mountain forest in the southern Cape in 1996. Our study indicated that this fire was one of at least two fires that influenced the recent history of this forest; the other fire was probably the great fire of 1869. We consider the latter fire typical of fires that burn mountain forest and suggest a return period for these fires of between a 100 and 200 years. In contrast to the 1869 fire| evidence from our study suggests that the 1996 fire was unprecedented in the recent history of the forest. This fire changed a large proportion of Ocotea bullata in the margin from single stemmed to multistemmed trees and reduced the number of Cyathea capensis in the margin by 68%. Using these species as indicators| we argue that similar fires will reduce the structure and diversity of mountain forests as a whole. The 1996 fire was fuelled by abnormally high fuel loads associated with surrounding pine plantations and mountain fynbos invaded by woody aliens. Given that large areas of mountain fynbos are invaded by woody aliens| that large areas of the southern Cape are afforested and that global climate change is likely to lead to an increase in the conditions favouring intense fires| we consider effective management of Afromontane mountain forests essential. 2919,2002,2,4,Future projections for Mexican faunas under global climate change scenarios,Global climates are changing rapidly| with unexpected consequences(1). Because elements of biodiversity respond intimately to climate as an important driving force of distributional limitation(2)| distributional shifts and biodiversity losses are expected(3|4). Nevertheless| in spite of modelling efforts focused on single species(2) or entire ecosystems(5)| a few preliminary surveys of fauna-wide effects(6|7)| and evidence of climate change-mediated shifts in several species(8|9)| the likely effects of climate change on species' distributions remain little known| and fauna-wide or community-level effects are almost completely unexplored(6). Here| using a genetic algorithm and museum specimen occurrence data| we develop ecological niche models for 1|870 species occurring in Mexico and project them onto two climate surfaces modelled for 2055. Although extinctions and drastic range reductions are predicted to be relatively few| species turnover in some local communities is predicted to be high (> 40% of species)| suggesting that severe ecological perturbations may result. 5884,2002,3,4,Future trends in the management of livestock production,The intensification of animal production systems proceeded rapidly in the latter part of the twentieth century| often aided by government support. However| only short-term benefits of intensification were realized and consumers started to select animal produce from less intensive production systems in the belief that it would be healthier| kinder to the animals and less likely to cause damage to the environment. Recent research has shown that the production of high quality traditional dairy products will provide an income for more people than intensive dairy production| thus helping to serve as a functional basis for rural land use. It is Often argued that extensive production cannot produce enough food for the majority of the population| but such estimates rely on outdated and inadequate levels of output from the traditional systems. Modern organic dairy systems|for example| should produce at least two-thirds of that of intensive systems and should therefore be able to provide for the majority of consumers in the UK. However| it is anticipated that increased global trade in livestock products will further threaten the livelihood of UK producers. Their options are to reduce input costs and develop specialized markets for high quality products ahead of their competitors. For example| the increased potential lifespan of the human population will encourage people to consume products that promote longevity| such as those with minimal contamination by pollutants. In many parts of the world| but particularly in the central continental land masses| livestock production will be challenged by global warming. Traditional production systems are likely to survive better| as they are buffered against variations in weather. It is concluded that livestock production systems have the potential to provide high quality food and employment| especially in marginal areas| and to preserve the land for the benefit of future generations. However| if badly managed| intensive systems may lead to major adverse effects on the environment| damage to human health and a reduction in food supply for those in developing countries. 5931,2002,2,4,Gas dynamics in eutrophic lake sediments affected by oxygen| nitrate| and sulfate,In many freshwater ecosystems| the contents of NO3- and SO42- have increased| whereas O-2 has been depleted due to the increased acid and nutrient loads. These changes may. affect carbon turnover and the dynamics of the major greenhouse gases CO2| CH4| and N2O. We studied the effects of O-2| NO3-| and SO42- availability on carbon mineralization| and fluxes of CO2| CH4| and N2O in the sediments of hypermeutrophic Lake Kevaton| Finland. Undisturbed sediment cores from the deep (9 m) and shallow (4 m) profundal were incubated in a laboratory microcosm with oxic and anoxic water flows with NO3- or SO42- concentrations of 0| 30| 100| 300| and 2000 muM. The carbon mineralization rate (i.e.| the sum of released CO2-C and CH4-C) was not affected by the oxidants. However| the oxidants did change the pathways of carbon degradation and the release of CH4. All of the oxidants depressed CH4. fluxes in the shallow profundal sediments| which had low organic matter content. In the deep profundal sediments rich in organic matter| the CH4 release was reduced by O-2 but was not affected by SO42- (the effect of NO3- was not studied). There was an increase in N2O release as the overlying water NO3- concentration increased. Anoxia and highly elevated NO3- concentrations| associated with eutrophication| increased drastically the global warming potential (GWP) of the sedimentary gases in contrast to the SO42- load| which had only minor effects on the GWP. 2894,2002,2,4,Gas exchange| biomass| whole-plant water-use efficiency and water uptake of peach (Prunus persica) seedlings in response to elevated carbon dioxide concentration and water availability,We examined the interactive effects of elevated CO2 concentration ([CO2]) and water stress on growth and physiology of 1-year-old peach (Prunus persica L.) seedlings grown in 10-dm(3) pots in open-top chambers with ambient (350 mumol mol(-1)) or elevated (700 mumol mol(-1)) [CO2]. Seedlings were supplied weekly with a non-limiting nutrient solution. Water was withheld from half of the plants in each treatment for a 4-week drying cycle| to simulate a sudden and severe water stress during the phase of rapid plant growth. Throughout the growing season| seedlings in elevated [CO2] had higher assimilation rates| measured at the growth [CO2]| than seedlings in ambient [CO2]| and this caused an increase in total dry mass of about 33%. Stomatal conductance| total water uptake| leaf area and leaf number were unaffected by elevated [CO2]. Because seedlings in the two CO2 treatments had similar transpiration despite large differences in total dry mass| water-use efficiency (WUE) of well-watered and water-stressed seedlings grown in elevated [CO2] was an average of 51 and 63% higher| respectively| than WUE of comparable seedlings grown in ambient [CO2]. Elevated [CO2] enhanced total biomass of water-stressed seedlings by 31%| and thus ameliorated the effects of water limitation. However| the percentage increases in total dry mass between well-watered and water-stressed seedlings were similar in ambient (53%) and elevated (58%) [CO2]| demonstrating that there was no interaction between elevated [CO2] and water stress. This finding should be considered when predicting responses of trees to global climate change in hot and dry environments| where predicted temperature increases will raise evaporative demands and exacerbate the effects of drought on tree growth. 5680,2002,4,4,General circulation model simulations of recent cooling in the east-central United States,[1] In ensembles of retrospective general circulation model (GCM) simulations| surface temperatures in the east-central United States cool between 1951 and 1997. This cooling| which is broadly consistent with observed surface temperatures| is present in GCM experiments driven by observed time varying sea-surface temperatures (SSTs) in the tropical Pacific| whether or not increasing greenhouse gases and other time varying climate forcings are included. Here we focus on ensembles with fixed radiative forcing and with observed varying SST in different regions. In these experiments the trend and variability in east-central U. S. surface temperatures are tied to tropical Pacific SSTs. Warm tropical Pacific SSTs cool U. S. temperatures by diminishing solar heating through an increase in cloud cover. These associations are embedded within a year-round response to warm tropical Pacific SST that features tropospheric warming throughout the tropics and regions of tropospheric cooling in midlatitudes. Precipitable water vapor over the Gulf of Mexico and the Caribbean and the tropospheric thermal gradient across the Gulf Coast of the United States increase when the tropical Pacific is warm. In observations| recent warming in the tropical Pacific is also associated with increased precipitable water over the southeast United States. The observed cooling in the east-central United States| relative to the rest of the globe| is accompanied by increased cloud cover| though year-to-year variations in cloud cover| U. S. surface temperatures| and tropical Pacific SST are less tightly coupled in observations than in the GCM. 5935,2002,2,4,Genetic diversity| mating system| and conservation of a Mexican subalpine relict| Picea mexicana Martinez,Mexican spruce (Picea mexicana Martinez)| an endangered species of the highest sky islands in Mexico's Sierra Madre Oriental and Sierra Madre Occidental| is threatened by fire| grazing| and global warming. Its conservation depends on whether it also is threatened by inbreeding and loss of genic diversity. We used 18 isozyme markers in 12 enzyme systems to assay genic diversity| characterize the mating system| and test for recent bottlenecks in three known populations. Unbiased| expected heterozygosity (H-e) averaged 0.125. Despite a separation of 676 km between populations in the Sierra Madre Oriental and the Sierra Madre Occidental| Wright's F-ST| the proportion of total genic diversity among populations| was only 6.9%. Nei's genetic distance was 0.001 between the populations in the Sierra Madre Oriental and more than an order of magnitude greater| 0.019| between the Sierra Madre Oriental and Sierra Madre Occidental. However| both values point to relatively recent divergence. Mating systems were predominantly outcrossing| but with significant selling. Multilocus estimates of selling varied from 19% to 41%| and the means of single-locus estimates were higher| suggesting that additional inbreeding occurred by mating among relatives. Despite significant inbreeding| observed heterozygosity was as high as or higher than H-e; Wright's fixation index| F-IS| was -0.107. Under the observed level of selfing| positive values of F-IS were expected. Therefore| selection against inbreds and homozygotes must be intense. Cornuet-Luikart tests indicate recent bottlenecks in at least two of the three populations. The results suggest that Mexican spruce is a genetically viable species| and threats are primarily environmental. 2910,2002,2,4,Genetic variation and population structure in central and isolated populations of balsam fir| Abies balsamea (Pinaceae),Genetic variation and spatial genetic structure in balsam fir (Abies balsamea) were examined in two isolated populations in Iowa and Minnesota thought to be paleorefugia and in two ecologically central populations in old-growth forests of Upper Michigan. Overall levels of genetic variability at 22 allozyme loci were lower than that found in most conifer species (H-o values ranged from 0.005 in the isolated populations to 0.025 in the central populations). The mean F-IS value (0.154) was larger than usually found in conifers and suggests moderate levels of inbreeding. The mean F-ST| an estimate of genetic diversity among populations| was 3.7% of the total diversity| a value lower than the mean for conifers. Nm| the number of migrants per generation| was 6.5| suggesting either some gene flow among populations or a lack of genetic differentiation. Spatial autocorrelation analysis revealed a moderately patchy structure| with gene flow distances of 30-70 m in the central populations and at least 10 m in the isolated populations. The future of the ecologically central populations depends on maintenance of an intact forest mosaic. The low genetic variability in the small| isolated populations suggests that habitat fragmentation has led to a reduction in evolutionary potential and that the future viability of these populations will likely require active management in the face of global climate change. 5908,2002,2,4,Geo-ecology and management of sensitive montane landscapes,Montane (alpine) areas are generally of high value for nature conservation. Such environments and the habitats they support are dynamic and often fragile. They are vulnerable to disturbance from a range of human activities and are responsive to climate changes over short and long timescales. Biodiversity and conservation values are closely linked to geological history| geomorphological processes and soils| and it is crucial that management systems are based on understanding these links. There are many similarities between the Cairngorm Mountains (Scotland)| the Giant Mountains (Czech Republic) and Abisko Mountains (Sweden) in terms of geology| geomorphology| ecology| links with biodiversity and high conservation importance. Comparable pressures and management issues involve| to varying degrees| a history of human use and impacts from deforestation| pasturing| grazing| recreation and atmospheric pollution. Landscape change therefore involves a complex interplay between natural and anthropogenic factors. Managing such change requires better understanding of the geo-ecological processes involved and the factors that determine landscape sensitivity. This is illustrated through a simple framework and examples from the three areas. Comparison of landscape sensitivity between similar montane areas| but in different geographic locations and climatic environments| should allow more informed management planning and a precautionary approach in advance of further changes in human activity and from predicted global warming scenarios. 5898,2002,3,2,Geological sequestration of anthropogenic carbon dioxide in the western Canada sedimentary basin: Suitability analysis,Geological sequestration of anthropogenic carbon dioxide is a potential solution to the release into the atmosphere Of CO2| a greenhouse gas thought of as significantly contributing to the global warming trend observed since the beginning of the industrial revolution. Basically| CO2 can be sequestered in geological media: 1) through enhanced oil recovery (EOR)| 2) by storage in depleted oil and gas reservoirs| 3) through replacement by CO2 of methane in deep coal beds (ECBMR)| 4) by injection into deep saline aquifers| and 5) by storage in salt caverns. Criteria in assessing the suitability of a sedimentary basin for CO2 sequestration are: a) tectonism and geology| b) the flow of formation waters and geothermal regime| and c) the existence of storage media (hydrocarbon reservoirs| coal seams| deep aquifers and salt structures). Generally| the Western Canada Sedimentary Basin is suitable for CO2 sequestration by all means because it is tectonically stable| it has regional-scale aquifers confined by aquitards or aquicludes| and it has oil and gas reservoirs in various stages of depletion| uneconomic coal seams| and extensive salt beds. However| various regions in the basin have different degrees of suitability| ranging from not suitable along the eastern edge of the basin| to extremely suitable in southwestern and central Alberta. Most major CO2 producers| such as power plants and refineries around Edmonton| are found in regions that are unsuitable for CO2 sequestration in geological media; however| some| such as the oil sands plants in the Athabasca area| are in regions that are not suitable. This analysis of the suitability of the Western Canada Sedimentary Basin for CO2 sequestration in geological media should provide industry and governments with essential information needed for developing plans and policies in response to climate change effects of anthropogenic greenhouse gas emissions into the atmosphere. 2912,2002,2,4,GIS simulations of the inundation risk in the coastal lowlands of the Northern Adriatic Sea,The Northern Adriatic Coastland| between the cities of Monfalcone and Cattolica| is characterized by locations of great tourist interest| such as the Venice Lagoon and the Romagna Riviera| and areas with a very precarious environmental setting| such as the Valli di Comacchio| and the Po River Delta. Therefore| the coastal management and the design of new defence works of the littoral have to be made with the utmost care| possibly with the aid of numerical predictions of the coastal morphodynamics and the flood risk analysis of the lowland involved. In the study area| land may subside due to sediment natural compaction and subsurface fluid (water and gas) withdrawal. At the same time| littoral transport of solid material can contribute appreciably to change the shore morphology. Mean sea level may rise permanently due to global climate change (eustatism) and occasionally due to tides and intensive storm events. The predictions of each individual process is obtained using various ad hoc mathematical models and the outcome of the numerical simulations are managed with a GIS (geographical information system). Coastline evolution until the year 2100 is investigated and risk factor maps of the low-lying coastal areas are generated which account for the hazard of the expected event| and the land economic value and vulnerability. (C) 2002 Elsevier Science Ltd. All rights reserved. 5903,2002,2,4,Glacier foreland colonisation: distinguishing between short-term and long-term effects of climate change,By comparing short-term (6 years) observations with long-term (>100 years): community changes reconstructed from the chronosequence along a glacier foreland| I show that the colonisation of recently deglaciated terrain by invertebrates may constitute a process reacting sensitively to temperature fluctuations. Early colonising stages (<30 years old) currently develop faster| and intermediate successional stages (30 50 years| old) slower| than would be indicated by the long-term chronosequence pattern. These differences between the chronosequence approach and direct observation can be explained by a simple model relating the rate of community evolution to the temperature record. It would mean that an increase of 0.6degreesC in summer temperatures approximately doubled the speed of initial colonisation| whereas later successional stages were less sensitive to climate change. The present situation appears to result from unusually warm summers around 1950 and a warm period accelerating glacier retreat since 1980. In contrast to the long-term trend| all except the youngest communities have suffered a loss in diversity in recent years. 2913,2002,2,4,Global climate change and health: Challenges for future practitioners,http://www.bvsde.paho.org/bvsacd/cd68/JPatz3.pdf
OVERVIEW
Global climate change is expected to have broad health im- pacts.1 If current warming trends continue| heat waves| floods| and droughts and their attendant physical effects are likely to become more frequent and severe. Warmer air tem- peratures can influence the concentration of regional air pol- lutants and aeroallergens. Less direct health impacts may result from the disruption of ecosystems and of water and food supplies| which in turn could affect infectious disease incidence and nutritional status. Finally| sea-level rise could lead to major population displacement and economic disruption.
2905,2002,2,4,Global climate change and sea level rise: Potential losses of intertidal habitat for shorebirds,Global warming is expected to result in an acceleration in Current rates of sea level rise| inundating many low-lying coastal arid intertidal areas. This could have important implications for organisms that depend on these sites| including shorebirds that rely on them for feeding habitat during their migrations and in winter. We modeled the potential changes in the extent of intertidal foraging habitat for shorebirds at five sites in the United States that currently-support internationally important numbers of migrating and wintering birds. Even assuming a conservative global warming scenario of 2degreesC within the next century (the most recent projections range between 1.4degreesC and 5.8degreesC)| we project major intertidal habitat loss at four of the sites (Willapa Bay| Humboldt Bay| San Francisco Bay| arid Delaware Bay). Projected losses range between 20% and 70% of current intertidal habitat. Such losses might jeopardize the ability of these sites to continue to support their current shorebird numbers. The most Severe losses are likely to occur at sitcom where the coastline is unable to move inland because of steep topography or seawalls. The effects of sea level rise may be exacerbated by additional anthropogenic factors. In southern San Francisco Bay| for example| sea level rise may interact with land subsidence due to aquifer depletion| and the constraints imposed by existing seawalls on the landward migration of habitat| resulting in the greatest habitat loss. At the fifth site (Bolivar Flats) we project smaller losses as the intertidal habitat: are unconstrained by sea walls and will be able to migrate inland in response to rising sea level. Installation of additional coastal protection barriers at this site and others is likely to exacerbate the rate and extent of intertidal habitat loss. 5844,2002,4,4,Global cooling after the eruption of Mount Pinatubo: A test of climate feedback by water vapor,The sensitivity of Earth's climate to an external radiative forcing depends critically on the response of water vapor. We use the global cooling and drying of the atmosphere that was observed after the eruption of Mount Pinatubo to test model predictions of the climate feedback from water vapor. Here| we first highlight the success of the model in reproducing the observed drying after the volcanic eruption. Then| by comparing model simulations with and without water vapor feedback| we demonstrate the importance of the atmospheric drying in amplifying the temperature change and show that| without the strong positive feedback from water vapor| the model is unable to reproduce the observed cooling. These results provide quantitative evidence of the reliability of water vapor feedback in current climate models| which is crucial to their use for global warming projections. 5747,2002,4,4,Global ocean emission of dimethylsulfide predicted from biogeophysical data,Among the biosphere-atmosphere interactions that influence climate| the emission of dimethylsulfide (DMS) from the ocean plays a prominent role for its high potential in cloud albedo regulation. In order to advance in our understanding and quantification of this coupled ocean-atmosphere system| both synoptic and predictive capabilities must be largely improved. Hitherto| large-scale oceanic DMS has eluded being captured from remote sensing| correlated with synoptic variables| or simulated by mechanistic modeling. We have found a simple empirical relationship that permits global-ocean monthly distributions of DMS concentration to be computed from a combination of remotely sensed biospheric data (chlorophyll a) and climatological geophysical data (mixed layer depth). This relationship allows for the desired synopticity and predictability in the ocean-to-atmosphere sulfur flux| which we have globally quantified as 23-35 Tg S yr(-1). Also| our algorithm stands in support of a biogenic-DMS/solar-radiation negative feedback and opens the door toward quantifying its strength and its response to global warming. 5787,2002,2,2,Global warming - Effects on plants,The burning of fossil fuels| the large-scale clearing of forests| and other human activities are altering global climates at an alarming rate. The continued consumption of fossil fuels is expected to result in a doubling of the current [CO2] by sometime in this century. These increases in CO2 as well as other “greenhouse gasses” are expected to raise world temperatures by 0.03°C per year in the 21st century. Global warming and increased atmospheric [CO2] are already having a major impact on plant distributions. Plants| in general| benefit from slightly warmer temperatures and higher [CO2]| but not all plants will benefit equally from these conditions| and some may even be harmed: There will be winners and losers in the warmer world of the near future. If the past is any indicator| the losers may greatly outnumber the winners. Pala-eobotanical evidence indicates that there was a 4-fold increase in atmospheric [CO2] across the Triassic-Jurassic boundary and an associated 3°C to 4°C “greenhouse” warming (McElwain et al.| 1999). These environmental conditions were calculated to have raised leaf temperatures above a highly conserved lethal limit| perhaps contributing to the >95% species-level turnover of Triassic-Jurassic megaflora. Are we destined to witness a floral mass extinction of similar proportions in the coming few centuries? The data and models discussed in this month's column suggest that the mass extinction| or at least the mass ecological upheaval| has already begun.
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An LCA case study was conducted for the production of lead and zinc by an Imperial Smelting Process (abbreviated hereafter as ISP) in Shaoguan Smelter| China. The detailed inventory analysis was performed by allocating the Input/Output among the main products. The environmental impacts were assessed by using the following five Eco-indicators: Gross Energy Requirement (GER)| Global Warming Potential (GWP)| Acidification Potential (AP)| Heavy Metal Toxicity (HMT) and Solid Waste Burden (SWB). This study is useful to address the environmental situation of the ISP practiced in this smelter| and provides a scientific basis for further improvement.
2920,2002,3,4,Leaders| pushers and laggards in the making of the climate regime,The primary motivation for this paper is to illuminate the role of leadership exerted by individuals| institutions and nation-states at various stages of the global climate change regime| Four forms of leadership: intellectual| instrumental| power-based| and directional| are identified| Next| theoretical claims about the dominance of particular forms of leadership at particular stages of regime formation are empirically tested by examining the agenda setting and negotiation phases of the climate regime. This analysis tends to support theoretical claims that intellectual leadership is particularly prominent during agenda setting| but evidence to support the influence of entrepreneurial leaders during negotiations is mixed at best for the climate regime. Structural or power based leadership meanwhile was largely absent during agenda setting of the climate regime but has been in clear evidence through the negotiations of the Climate Convention and the Kyoto Protocol. (C) 2002 Elsevier Science Ltd. All rights reserved. 5928,2002,3,4,Life cycle inventory analysis of hydrogen production by the steam-reforming process: comparison between vegetable oils and fossil fuels as feedstock,A life cycle inventory analysis has been conducted to assess the environmental load| specifically CO2 (fossil) emissions and global warming potential (GWP)| associated to the production of hydrogen by the steam reforming of hydrocarbon feedstocks (methane and naphtha) and vegetable oils (rapeseed oil| soybean oil and palm oil). Results show that the GWPs associated with the production of hydrogen by steam reforming in a 100 years time frame are 9.71 and 9.46 kg CO2-equivalent/kg H-2 for natural gas and naphtha| respectively. For vegetable oils| the GWP decreases to 6.42 kg CO2-equivalent/ kg H-2 for rapeseed oil| 4.32 for palm oil and 3.30 for soybean oil. A dominance analysis determined that the part of the process that has the largest effect on the GWP is the steam reforming reaction itself for the fossil fuel-based systems| which accounts for 56.7% and 74% of the total GWP for natural gas and naphtha| respectively. This contribution is zero for vegetable oil-based systems| for which harvesting and oil production are the main sources of CO2-eq emissions. 5924,2002,3,4,Life-cycle assessment as an environmental management tool in the production of potable water,The environmental life cycle assessment (LCA) methodology was used in this study to calculate and compare the environmental burdens resulting from two different methods employed in the production of potable water in South Africa. One method employs conventional processes for the treatment of water and the other one is based on membrane filtration. All inputs (raw materials and energy) and outputs (products| by-products and emissions to air| water and soil) from the two methods were listed and quantified. These inputs and outputs cause different environmental impacts (global warming| ozone depletion| smog formation| acidification| nutrient enrichment| ecotoxicity and human toxicity) and the contribution of each method to each of these impact categories has been quantified| resulting in a score. The ISO (International Organisation for Standardisation) methodological framework for life cycle assessments guided this study. By using these methodologies and by tracing all the processes involved in the production of potable water to the interface with the environment| it was found that the main contributor to the overall environmental burden is the generation of electricity. This conclusion is valid for both methods investigated and in order to increase the environmental performance in the production of potable water the energy efficiency of waterworks should be increased. 5705,2002,4,3,Lifetimes of atmospheric species: Integrating environmental impacts,[1] The environmental damage caused by atmospheric pollutants is proportional to the duration of their effects. The global impacts of greenhouse gases (as measured by global warming potential) and ozone depleting substances (as measured by ozone depletion potential) have traditionally been calculated using the atmospheric lifetime of the source gas as a quantitative measure of the impact's duration| assuming that the gas quickly reaches a steady-state pattern which decays exponentially according to the lifetime. This assumed behavior obviously does not match the true rise and fall of impacts| particularly secondary ones like ozone depletion| that can be seen in numerical integrations or chemical mode decomposition. Here| the modes decomposition is used to prove that: (a) the steady-state pattern of impacts caused by specified emissions| multiplied by (b) the steady-state lifetime of the source gas for that emission pattern| is exactly equal to (c) the integral of all impacts - independent of the number and atmospheric residence times of secondary impacts. 5902,2002,2,4,Limited predictability of the future thermohaline circulation close to an instability threshold,Most ocean-atmosphere models predict a reduction of the thermohaline circulation for a warmer climate in the near future. Although a reduction in the Atlantic Ocean circulation appears to be a robust result| the question remains open whether the climate system could possibly cross a critical threshold leading to a complete shutdown of the North Atlantic deep-water formation. Ensemble simulations with an ocean-atmosphere climate model of reduced complexity are performed to investigate the range of possible future climate evolutions when the climate system is close to such a threshold. It is found that the sensitivity of the ocean circulation to perturbations increases rapidly when approaching the bifurcation point| thereby severely limiting the predictability of future climate. At the bifurcation point| different response types such as linear responses| nonlinear transitions| or resonance behavior are observed. Close to the threshold| thermohaline shutdowns can occur thousands of years after the warming has stopped. A characterization of the probability for the different response types reveals a more complex picture for the future evolution of the ocean circulation than previously assumed. These results raise fundamental questions of how far the large differences in projections of the Atlantic circulation response to global warming are caused by different representations of processes| parameterizations| and/or resolution in individual models and whether the predictability of the Atlantic circulation becomes inherently limited when approaching a bifurcation point. 5702,2002,2,4,Linking climate change and biological invasions: Ocean warming facilitates nonindigenous species invasions,The spread of exotic species and climate change are among the most serious global environmental threats. Each independently causes considerable ecological damage| yet few data are available to assess whether changing climate might facilitate invasions by favoring introduced over native species. Here| we compare our long-term record of weekly sessile marine invertebrate recruitment with interannual variation in water temperature to assess the likely effect of climate change on the success and spread of introduced species. For the three most abundant introduced species of ascidian (sea squirt)| the timing of the initiation of recruitment was strongly negatively correlated with winter water temperature| indicating that invaders arrived earlier in the season in years with warmer winters. Total recruitment of introduced species during the following summer also was positively correlated with winter water temperature. In contrast| the magnitude of native ascidian recruitment was negatively correlated with winter temperature (more recruitment in colder years) and the timing of native recruitment was unaffected. In manipulative laboratory experiments| two introduced compound ascidians grew faster than a native species| but only at temperatures near the maximum observed in summer. These data suggest that the greatest effects of climate change on biotic communities may be due to changing maximum and minimum temperatures rather than annual means. By giving introduced species an earlier start| and increasing the magnitude of their growth and recruitment relative to natives| global warming may facilitate a shift to dominance by nonnative species| accelerating the homogenization of the global biota. 5698,2002,2,4,Linking global circulation model synoptics and precipitation for western North America,Synoptic downscaling from global circulation models (GCMs) has been widely used to develop local and regional-scale future precipitation scenarios under global warming. This paper presents an analysis of the linkages between the Canadian Centre for Climate Modelling and Analysis first version of the Canadian Global Coupled Model (CCCma CGCM1) 2000 model output and local/regional precipitation time series. The GCM 500 hPa geopotential heights were visually classified for Synoptic patterns using a geographical information system. The pattern frequencies were statistically compared with historical data from Chan-non et al. (1993. Monthly| Weather Review 121: 633-647) for the winter period 1961-85| The CGCM1 synoptic frequencies compare favourably with the historical data. and they represent a Substantial improvement over the 1992 Canadian Climate Centre Global Circulation Model Synoptic climatology Output. The CGCM1 output was used to forecast future winter precipitation scenarios for five geographically diverse climate stations in western North America. Copyright (C) 2002 Royal Meteorological Society. 5744,2002,2,3,Linking ozone pollution and climate change: The case for controlling methane,[1] Methane (CH4) emission controls are found to be a powerful lever for reducing both global warming and air pollution via decreases in background tropospheric ozone (O-3). Reducing anthropogenic CH4 emissions by 50% nearly halves the incidence of U.S. high-O-3 events and lowers global radiative forcing by 0.37 W m(-2) (0.30 W m(-2) from CH4| 0.07 W m(-2) from O-3) in a 3-D model of tropospheric chemistry. A 2030 simulation based upon IPCC A1 emissions projections shows a longer and more intense U.S. O-3 pollution season despite domestic emission reductions| indicating that intercontinental transport and a rising O-3 background should be considered when setting air quality goals. 5901,2002,3,3,Links between Cairo and Kyoto: Addressing global warming through voluntary family planning,Over the past three decades| with a combination of new technology| rising female literacy rates| and strengthened family planning programs| the world has seen dramatic increases in the use of contraception| with corresponding declines in fertility and population growth rates. At the International Conference on Population and Development| Cairo in 1994| parties pledged a tripling of funding for reproductive health programs in developing countries. Many demographers believe that making such programs more widely available to women would extend the decline in birth rates and shift the world towards the low scenario of United Nations population projections over the next century and a half. By examining the costs and impacts of such programs| in view of the links between population and carbon emissions| this paper shows that extension of voluntary family planning could make a large and cost-effective contribution to the greenhouse gas limitation goals of the Kyoto Protocol that was negotiated in 1997. 5862,2002,2,4,Localization of abrupt change in the North Atlantic thermohaline circulation,[1] Recent climate model experiments| as well as paleoclimate records| suggest that the meridional overturning circulation or "thermohaline circulation'' in the Atlantic Ocean could change abruptly as a result of global warming| and that this could have a significant impact on European climate. We use a reduced-gravity model to investigate the response of the Atlantic overturning circulation to changes in forcing. We find that variability at decadal and higher frequencies is confined to a single hemisphere. This implies that (a) overturning variability resulting from high frequency changes in buoyancy forcing in the Labrador and Greenland Seas will be limited to the North Atlantic| and (b) any observed decadal and higher frequency fluctuations in North Atlantic overturning can only result from changes in the surface fluxes within the North Atlantic basin itself. These results suggest that Southern Ocean wind forcing is not important for North Atlantic overturning on decadal and shorter timescales. 5788,2002,2,4,Long-term decline in abundance and distribution of the garden tiger moth (Arctia caja) in Great Britain,The garden tiger moth (Arctia caja) was once widespread and common in the UK. Data collected using the standard light-traps of the Rothamsted Insect Survey over Great Britain from 1968 to 1998 showed that A. caja abundance fluctuated near 4.2 captures per site until 1983| and then fell 28% to an average of 3.0 captures per site after 1984. The collated index| frequently used to monitor UK butterfly abundance| was not suitable to detect this large| 1-year population change. Four years after the sudden decrease in abundance| the proportion of sites occupied also fell rapidly from an average of 0.60 to an average of 0.42 (30%). Contrary to most UK butterflies| which are expected to increase under the UK climate change scenarios of global warming| linear regression modelling showed that warm| wet winters and springs may be detrimental to A. caja and it is therefore predicted to decrease further. (C) 2002 Elsevier Science Ltd. All rights reserved. 5699,2002,2,4,Long-term dynamics of coral reefs in St. John| US Virgin Islands,In this study| long-term (1987-1998) dynamics are described on a local scale (<20 km) for coral reefs in St. John| US Virgin Islands| which are located in a marine protected area (MPA). The study consists of two sites (Yawzi and Tektite) which were selected in 1987 based on relatively high coral cover (=32%)| and six sites that were randomly selected in 1992. Over 12 years| mean coral cover at Yawzi (9 in depth) changed significantly| declining from 45 to 20% cover between 1987 and 1998 (a 56% reduction). Less than I kin away at Tektite (14 in depth)| coral cover also changed significantly| but here. it increased 34% (from 32 to 43% cover). Over the same period| macroalgal cover showed a significant upward trend at both sites| increasing from 2 to 26% at Yawzi| and from 6 to 13% at Tektite. The random sites (7-9 in depth) differed from the initial sites in both community structure and dynamics. Mean coral cover at the random sites (similar to8%) was less than one third of that at Yawzi and Tektite| and varied significantly among sites and years in an idiosyncratic pattern. The percentage cover of macroalgae and the pooled coverage of crustose coralline algae| algal turf| and bare space showed a strong site x time interaction| illustrating that the sites differed in dynamics| but that the differences varied among times. Thus| as has been reported elsewhere in the Caribbean| serious reef degradation has occurred on at least one reef in St. John| but the patterns of change vary markedly on a kilometer-wide scale. In comparison with other long-term studies of Caribbean coral reefs| the degradation of a coral reef in an MPA around St. John is noteworthy since there are few local anthropogenic disturbances that can be held responsible for the decline. The strong possibility that large-scale events such as hurricanes and global warming have played a pivotal role in the decline of at least one reef in St. John emphasizes the need to embrace landscape- and regional-scale phenomena in order to understand and manage local coral reef dynamics. The occurrence of small patches of relatively healthy reef (i.e.| at Tektite) appears trivial in comparison to region-wide reef decline| but such anomalies should be studied further because of their potential roles as refugia for corals and reef-associated taxa. 5915,2002,3,3,Long-term effects of tillage| cover crops| and nitrogen fertilization on organic carbon and nitrogen concentrations in sandy loam soils in Georgia| USA,Maintaining and/or conserving organic carbon (C) and nitrogen (N) concentrations in the soil using management practices can improve its fertility and productivity and help to reduce global warming by sequestration of atmospheric CO2 and N-2. We examined the influence of 6 years of tillage (no-till| NT; chisel plowing| CP; and moldboard plowing| MP)| cover crop (hairy vetch (Vicia villosa Roth.) vs. winter weeds)| and N fertilization (0| 90| and 180 kg N ha(-1)) on soil organic C and N concentrations in a Norfolk sandy loam (fine-loamy| siliceous| thermic| Typic Kandiudults) under tomato (Lycopersicon esculentum Mill.) and silage corn (Zea mays L.). In a second experiment| we compared the effects of 7 years| of non-legume (rye (Secale cereale L.)) and legume (hairy vetch and crimson clover (Trifolium incarnatum L.)) cover crops and N fertilization (HN (90 kg N ha(-1) for tomato and 80 kg N ha(-1) for eggplant)) and FN (180 kg N ha(-1) for tomato and 160 kg N ha(-1) for eggplant) on soil organic C and N in a Greenville fine sandy loam (fine-loamy| kaolinitic| thermic| Rhodic Kandiudults) under tomato and eggplant (Solanum melogena L.). Both experiments were conducted from 1994 to 2000 in Fort Valley| GA. Carbon concentration in cover crops ranged from 704 kg ha(-1) in hairy vetch to 3704 kg ha(-1) in rye in 1999 and N concentration ranged from 77 kg ha(-1) in rye in 1996 to 299 kg ha(-1) in crimson clover in 1997. With or without N fertilization| concentrations of soil organic C and N were greater in NT with hairy vetch than in MP with or without hairy vetch (23.5-24.9 vs. 19.9-21.4 Mg ha(-1) and 1.92-2.05 vs. 1.58-1.76 Mg ha(-1) respectively). Concentrations of organic C and N were also greater with rye| hairy vetch| crimson clover| and FN than with the control without a cover crop or N fertilization (17.5-18.4 vs. 16.5 Mg ha(-1) and 1.33-1.43 vs. 1.31 Mg ha(-1)| respectively). From 1994 to 1999| concentrations of soil organic C and N decreased by 8-16% in NT and 15-25% in CP and MP. From 1994 to 2000| concentrations of organic C and N decreased by 1% with hairy vetch and crimson clover| 2-6% with HN and FN| and 6-18% with the control. With rye| organic C and N increased by 3-4%. Soil organic C and N concentrations can be conserved and/or maintained by reducing their loss through mineralization and erosion| and by sequestering atmospheric CO2 and N-2 in the soil using NT with cover crops and N fertilization. These changes in soil management improved soil quality and productivity. Non-legume (rye) was better than legumes (hairy vetch and crimson clover) and N fertilization in increasing concentrations of soil organic C and N. (C) 2002 Elsevier Science B.V. All rights reserved. 5959,2002,4,4,Long-term trends in geomagnetic and climatic variability,Causes leading to global mean sea surface temperature (GT) variability and to variations of the global Circulation including the North Atlantic Oscillation (NAO) and El Nino (EN) events are examined. Statistically significant correlation coefficients between these variables were found and their relations are discussed with the aim to show possible causes leading to general year-to-year variability and to the global warming. At the same time| the results contribute to the verification of the hypothesis as given in our previous papers. We have suggested a link of processes generated by geomagnetic forcing that is followed by dramatic shifts in the atmospheric circulation patterns. At times of low geomagnetic activity in winter the meridional flow prevails contributing to the strong heat exchange of air between low and high latitudes. The arctic air penetrates from polar areas and participates in the cooling of middle latitudes; the NAO winter index (WI) is negative. At times of high geomagnetic activity the Icelandic low intensifies and influences the strengthening of the zonal flow in the Northern Hemisphere; the NAO WI is positive. A continuous zone of high pressure originates along middle latitudes and a little north-south motion of air takes place. In mid-latitudes above-normal temperatures occur while in polar areas the values are below normal. The strong Australian high at times of low geomagnetic activity seems to initiate EN events while the zonal flow in the Southern Hemisphere intensifies monsoon rains in the Indian Ocean when geomagnetic activity is high. EN and NAO events are shown to take part in the variability of GT. Controversial problems are discussed as well. (C) 2002 Elsevier Science Ltd. All rights reserved. 5937,2002,4,4,Long-term variations and interrelations of ENSO| NAO and solar activity,Much attention is recently paid to the global warming observed in the 20th century| and especially to the relative impact of natural and anthropogenic factors responsible for it. Many studies have revealed a good correlation| up to the last decades| between century-scale changes in global surface temperature and solar activity| though the mechanism is still controversial. Long-term anomalies of atmospheric parameters are often connected to large-scale changes in atmospheric circulation influencing| through teleconnections| distant and apparently unconnected areas. Such large-scale phenomena are El Nino/Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) affecting the climate over a great part of the globe on interannual to decadal and centennial time-scales. Little is known about the factors determining the long-term variability of these phenomena. In the present paper we compare the century-long variability of NAO and ENSO with the solar activity variations in the secular (Gleissberg) solar cycle and find a close relation between them. We suggest that the influence of solar activity on these large-scale phenomena is mediated by atmospheric centers of action which undergo changes in intensity and location in response to long-term variations of solar activity. (C) 2002 Elsevier Science Ltd. All rights reserved. 5872,2002,2,4,Long-tern monitoring in the Netherlands suggests that lichens respond to global warming,There is evidence to suggest that part of the recent changes in the lichen flora of the Netherlands is attributable to an increase in temperature. Changes which have occurred over the last 22 years were studied in detail| and were subjected to a statistical treatment by comparing the change of species to their latitudinal distribution and to ecological determinants. All 329 epiphytic and terrestrial lichen species occurring in the Netherlands were considered in relation to their world distribution. Arctic-alpine/boreo-montane species appear to be declining| while (sub)tropical species are invading. The proportion of increasing species is by far the largest among the wide-tropical lichens (83%)| and smallest among the arctic-alpine/boreo-montane lichens (14%). None of the wide-tropical species was found to decrease| while 50% of the arctic-alpine/boreo-montane species show a decline. Long-term monitoring of the epiphytic lichen flora in the province of Utrecht from 1979 onwards shows that the total number of taxa present increased from 95 in 1979 to 172 in 2001| while the average number of taxa per site increased from 7.5 to 18.9. The rate of increase was greatest by far between 1989 and 1995. The majority of the species (152 taxa or 85%) show a gross increase| only 17 species (10%) show a decrease. A detailed analysis of these data using multiple regression suggests global warming as an additional cause for recent changes| next to decreasing SO(2) and increasing NH(3). Changes appear to be correlated initially (1979-1095) only with toxitolerance and nutrient demand. Changes between 1995 and 2001| however| appear positively correlated to both temperature and nutrient demand| indicating a recent and significant shift towards species preferring warm circumstances| independent from| and concurrent with changes due to nutrient availability. This is the first paper reporting long-term. floristic changes for lichens that appear to be correlated significantly with increasing temperatures. We suggest that future lichen monitoring programmes also pay attention to effects of climatic change| instead of focusing on air pollution effects only. (C) 2002 The British Lichen Society Published by Elsevier Science Ltd. All rights reserved. 5906,2002,3,4,Low energy electron attachment to SF(5)CF(3),Low energy electron attachment to the potent greenhouse gas SF(5)CF(3) is studied at high energy resolution by means of mass spectrometric detection of the product anions. A large dissociative electron attachment (DA) cross-section forming SF(5)(-) + CF(3) is observed within a very narrow energy range close to zero eV. In addition| comparatively weak resonances are observed near 1 eV yielding the fragment ions CF(3)(-) and F(-). Some implications for the atmospheric lifetime of SF(5)CF(3) and hence its global warming potential (GWP) are considered. (C) 2002 Elsevier Science B.V. All rights reserved. 5674,2002,2,4,Low frequency variability of tropical cyclone potential intensity - 1. Interannual to interdecadal variability,[1] Recent research suggests that anthropogenic global warming would be associated with an increase in the intensity of tropical cyclones. A recent statistical analysis of observed tropical cyclone intensity shows that its variability with location and season is strongly tied to the variability of the thermodynamic potential intensity (PI) of tropical cyclones| as calculated using a theory described in an earlier work by the authors. Thus it is of interest to look for possible trends in global measures of PI| which are far more stable than those of actual storm intensity. We estimate global trends of PI from 1958 to 1996| averaged over the region where it exceeds 40 m s(-1)| using the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis and the NCEP Empirical Orthogonal Function (EOF) sea surface temperature (SST) analysis. We adjust the Reanalysis temperatures for a large| spurious temperature increase that occurred around 1979. We do this by subtracting from the Reanalysis the atmospheric temperature difference between pairs of years with similar tropical SST before and after 1979. The value of the global mean PI is very large for the SST of the corresponding region in the mid-1990s. Supported by a recent study on the effects of ozone decrease on tropospheric temperatures| we suggest that the ozone decrease might be one of the factors contributing to increase of PI during the 1990s. 2927,2002,2,4,Macroecology of mangroves: large-scale patterns and processes in tropical coastal forests,Macroecology is an emerging subdiscipline within ecology that explores effects of large-scale processes on local| regional| and global patterns of species diversity and taxon-independent scaling of structural and functional relationships. Statistical analysis of these patterns yields hypotheses concerning the processes determining population| community| and ecosystem-level patterns| which have been the historical focus of most ecological research| including that done in mangroves. The majority of studies of mangrove forests have aimed to better understand the causes of local (within-forest) ecological patterns (e.g. zonation| tolerance to salinity and hypoxia| litter-fall and production)| with little attention to the larger environmental| historical and evolutionary contexts that can influence local processes. I argue that a focus on the larger-scale contexts that constrain local processes (a "macroecology of mangroves") will provide us with new insights into the structure and function of mangrove ecosystems. Further| such analyses can be used to determine if mangroves follow similar general rules that have been identified for upland forested ecosystems. I consider two examples: relationships between local species richness and latitude| longitude and regional diversity; and structural coordination of leaf traits. I present data and analyses of these macroecological patterns in mangrove forests| and illustrate points of agreement and disagreement between these and upland ecosystems. I suggest that ecological theory developed in upland forests can be readily applied to mangrove forests. Such a conclusion should lead to advances in ecological research of mangroves and better predictions of how they will respond to global climate change. 2843,2002,4,4,Making inferences about past environmental change using smoothing in multiple time scales,The concern about global climate change has heightened the need to understand past climatic variation. Temperature variation during the past thousands of years can be estimated from the relative abundances of fossils of various organisms in lake sediments. The past temperatures thus reconstructed suggest several periods of cooling and warming| and it is important to understand how much of the seeming variation is really statistically significant. The paper proposes an inference approach based on the SiZer method. Several different smooths of the reconstructed temperature are considered simultaneously making possible inferences about significant temperature trends at different time scales. The proposed method is applied to temperature reconstruction using a diatom fossil-based data set collected in the Finnish Lapland. The paper also suggests modifications and extensions to the original SiZer method that the present application calls for. (C) 2002 Elsevier Science B.V. All rights reserved. 5833,2002,2,4,Male-biased sex ratio in a small tuatara population,Aim We estimated population size| survival| longevity and sex ratio of tuatara (Sphenodon guntheri Buller 1877) on North Brother Island and determined whether recruitment was occurring| to aid management and identify potential problems for population viability. Location This study was conducted on North Brother Island| Cook Strait| New Zealand. This 4-ha island supports the sole remnant population of S. guntheri. Methods Demographic variables were estimated using capture-recapture methods. Tuatara were individually marked and recaptured during twelve trips| spanning a decade. Population size was estimated for selected trips using the CAPTURE package and finite mixture models| and survival was analysed using the Jolly-Seber (J-S) model. Longevity was estimated using tuatara individually marked in 1957. Results Approximately 350 adult tuatara profile likelihood interval (PLI) (294-427) inhabit North Brother Island| and the sex ratio is strongly biased towards males (1.7M : 1F). Annual adult survivorship is high (0.95) for both sexes and some tuatara live for at least 61 years. Main conclusions The small size and biased sex ratio of this population may make it susceptible to demographic stochasticity| Allee effects| and/or loss of genetic variation. Harvesting for translocation could exacerbate such problems. In addition| tuatara have temperature-dependent sex determination (TSD)| with males produced at higher incubation temperatures. Global warming may therefore skew the sex ratio further unless female nest site choice or adaptive shifts in pivotal temperatures compensate for rising temperatures. 2911,2002,2,4,Masting by eighteen New Zealand plant species: The role of temperature as a synchronizing cue,Masting| the intermittent production of large flower or seed crops by a population of perennial plants| can enhance the reproductive success of participating plants and drive fluctuations in seed-consumer populations and other ecosystem components over large geographic areas. The spatial and taxonomic extent over which masting is synchronized can determine its success in enhancing individual plant fitness as well as its ecosystem-level effects| and it can indicate the types of proximal cue| that enable reproductive synchrony. Here| we demonstrate high intra- and intergeneric synchrony in mast seeding by 17 species of New Zealand plants from four families across > 150 000 km(2). The synchronous species vary ecologically (pollination and dispersal modes) and are geographically widely separated| so intergeneric synchrony seems unlikely to be adaptive per se. Synchronous fruiting by these species was associated with anomalously high temperatures the summer before seedfall| a cue linked with the La Nina phase of El Nino-Southern Oscillation. The lone asynchronous species appears|| to respond to summer temperatures| but with a 2-yr rather than 1-yr time lag. The importance of temperature anomalies as cues for synchronized masting suggests that the timing and intensity of masting may be sensitive to global climate change| with widespread effects on taxonomically disparate plant and animal communities. 5896,2002,3,2,Materials for global carbon dioxide recycling,CO(2) emissions| which induce global warming| increase with the development of economic activity. It is impossible to decrease the CO(2) emissions by suppression of the economic activity. Global CO(2) recycling can solve this problem. The global CO(2) recycling consists of three district: The electricity is generated by solar cells on deserts. At desert coasts| the electricity is used for H(2) production by seawater electrolysis and H(2) is used for CH(4) production by the reaction with CO(2) CH(4) which is the main component of liquefied natural gas is liquefied and transported to energy consuming districts where CO(2) is recovered| liquefied and transported to the desert coasts. A CO(2) recycling plant for substantiation of our idea has been built on the roof of the Institute for Materials Research in 1996. Key materials necessary for the global CO(2) recycling are the anode and cathode for seawater electrolysis and the catalyst for CO(2) conversion. All or them have been tailored by us. They have very high activity and selectivity for necessary reactions in addition to excellent durability. A pilot plant consisting of minimum units in an industrial scale is going to be built in three years. (C) 2001 Elsevier Science Ltd. All rights reserved. 5689,2002,2,4,Meteorologic influences on Plasmodium falciparum malaria in the highland tea estates of Kericho| western Kenya,Recent epidemics of Plasmodium falciparum malaria have been observed in high-altitude areas of East Africa. Increased malaria incidence in these areas of unstable malaria transmission has been attributed to a variety of changes including global warming. To determine whether the reemergence of malaria in western Kenya could be attributed to changes in meteorologic conditions| we tested for trends in a continuous 30-year monthly malaria incidence dataset (1966-1995) obtained from complete hospital registers at a Kenyan tea plantation. Contemporary monthly meteorologic data (1966-1995) that originated from the tea estate meteorologic station and from global climatology records were also tested for trends. We found that total hospital admissions (malaria and nonmalaria) remained unchanged while malaria admissions increased significantly during the period. We also found that all meteorologic variables showed no trends for significance| even when combined into a monthly suitability index for malaria transmission. We conclude that climate changes have not caused the highland malaria resurgence in western Kenya. 5957,2002,4,4,Meteorological and micrometeorological applications to frost monitoring in northern Italy orchards,Late frost are dangerous climatic hazards that can be responsible of fruit trees yield losses. Late frost potential hazard is| in particular| increased by the enhancement of low-temperature episodes in spring and to the concomitant early-blooming consequent to higher winter temperatures induced by the earth global warming. This paper reports observations on the micrometeorological features associated to frost occurrence in a representative area of the Po valley in order to characterize the atmospheric physics during frost formation episodes| to understand the frequency and the type of risk and to develop the most suitable protection practices. Energy balance and soil radiation balance are reported together with the main atmospheric features (air turbulence included)| and the data-set collected are verified against the similarity equations. The computation of the surface roughness and the friction velocity| fundamental to the definition of the distinctive features of the site| has been also done by applying the similarity theory. (C) 2002 Elsevier Science Ltd. All rights reserved. 5810,2002,2,4,Meteorological conditions associated with sea surges in Venice: A 40 year climatology,The frequency of sea surges in Venice has increased during the 20th century| and the trend has been particularly pronounced in the last four decades. However| the time series of independent surge events (i.e. events separated by at least I week) has remained nearly stationary during that period. This suggests that| although the sea level rise (due to global warming and human activity in the region) is leading to more multiple events| the frequency of meteorological conditions that trigger independent events seems to be nearly balancing the effects of sea level change. Such meteorological conditions are identified by compositing sea level pressure (SLP) and 995 hPa wind during and before independent sea surge events in Venice. The composite analysis shows that these correspond to storms orographically induced over the western Mediterranean basin| when an Atlantic synoptic system is perturbed by the Pyrenees and/or the Alps. It is| however| the persistence| intensity and relative position of such storms to the Adriatic Sea that contribute to the optimum conditions for the occurrence of floodings in its northern embayment. It is shown that the synoptic picture is translated into persistent low SLP over the Venice region| negative north-south SLP gradient over the Adriatic| and south-southeasterly to southeasterly wind over the central and northern parts of the sea. During the 40 year period under analysis| the persistence and intensity of the most adverse scenarios for the occurrence of sea surges in Venice have been generally decreasing; significant trends have been found in the tails of the distributions of Venice SLP| SLP north-south gradient| and of surface wind over the northern Adriatic. It is the balance between these trends and the continuing sea level rise that may account for the near-stationarity of independent sea surge events during the last four decades. Copyright (C) 2002 Royal Meteorological Society. 2865,2002,5,4,Methane hydrate in the global organic carbon cycle,The global occurrence of methane hydrate in outer continental margins and in polar regions| and the magnitude of the amount of methane sequestered in methane hydrate suggest that methane hydrate is an important component in the global organic carbon cycle. Various versions of this cycle have emphasized the importance of methane hydrate| and in the latest version the role of methane hydrate is considered to be analogous to the workings of an electrical circuit. In this circuit the methane hydrate is a condenser and the consequences of methane hydrate dissociation are depicted as a resistor and inductor| reflecting temperature change and changes in earth surface history. These consequences may have implications for global change including global climate change. 5745,2002,2,4,Methane-limited methanotrophy in tidal freshwater swamps,[1] We investigated the relationship between CH4 production and oxidation in two tidal freshwater wetland forests in order to determine whether CH4 oxidation efficiency was limited by O-2 or CH4. Methane oxidation was measured in situ over a 16-month period with bi-monthly applications of the inhibitor CH3F. Oxidation consumed 52 +/- 10 and 81 +/- 9% of diffusive CH4 emissions on the two sites. Methane oxidation rates were linearly related to gross CH4 emissions on both sites (r(2) = 0.96)| demonstrating the process was CH4-limited. This interpretation is consistent with the fact that the apparent activation energies for the potential CH4 production and oxidation differed by <4 kJ mol(-1). Apparent activation energies calculated from field emissions data were also similar for the two processes. The high CH4 oxidation efficiency on these sites may be attributed to relatively low rates of methane production| a deep oxidizing zone (5-10 cm)| and low cover of understory vegetation capable of CH4 transport. If our results are typical of forested wetlands| CH4 oxidation efficiency in forested wetlands will not change in response to soil warming. 5808,2002,5,4,Microfacies| sequence stratigraphy and clay mineralogy of a condensed deep-water section around the Frasnian/Famennian boundary (Steinbruch Schmidt| Germany),A multidisciplinary analysis (microfacies| sequential stratigraphy and clay mineralogy) was made on Frasnian/Famennian (F/F) boundary strata of the Steinbruch Schmidt section in Western Germany. Three major microfacies are recognised. Their succession records a shallowing-upward evolution from deep| quiet and poorly oxygenated environments| below the storm wave base| to environments influenced by Current activities close to the storm wave base. The Kellwasser Horizons correspond to the deepest microfacies. The shallowest microfacies correspond to fine-grained calcareous tempestites or turbidites coming from a distant shelf of northwest Germany. The sequential pattern through the F/F boundary shows the succession of seven systems tracts. Two sequence boundaries are located just above the Lower Kellwasser Horizon and at the F/F boundary itself. These are underlined by hardgrounds suggesting time gaps. The Kellwasser Horizons correspond to sea-level highstands and the overlying beds record a transition from lowstand to transgressive systems tracts. Illite| and kaolinite are the dominant clay minerals associated with mixed layers and traces of chlorite. Illite abundance is maximal during Kellwasser Horizons. Illite and kaolinite were probably inherited from a highly weathered source area although part of the illite is diagenetic. Kaolinite is the second most abundant clay mineral and is particularly well represented (up to 50%) between the Kellwasser Horizons. An unusual clay assemblage of illite and mixed layers is associated with a bentonite layer. Kaolinite increases during times when thin tempestites or turbiditic microbioclastic layers come from a distant shelf during sea-level falls. The kaolinite percentage reaches its maximum at the top of the lowstand systems tract. The high percentage of kaolinite suggests a hot wet climate and could be related to global warming. (C) 2002 Elsevier Science B.V. All rights reserved. 5757,2002,3,3,Minimum mass solar shield for terrestrial climate control,The use of a large solar shield located sunward of the Sun-Earth interior Lagrange point is considered to offset increases in mean global surface temperature due to enhanced greenhouse warming. The three-body mechanics of the problem are investigated to optimize the shield location| thus minimizing the shield mass and improving on previous studies of this concept. While shield mass is minimized| the required mass is still of order 10(11) kg to offset an enhancement of greenhouse warming of order 2 K. Clearly| such schemes require significant technological capabilities| although the optimization presented in this paper reduces the scale of the problem to some extent. 5824,2002,3,4,Mitigating global warming: traditional versus alternative approaches in a planning versus a market context,Economic efficiency tends to be an important argument when different means of enviromental control are assessed and suggested. Considering that the most cost-efficient means are not the ones most frequently chosen and used| some other qualities seem to play an equally important role. I use findings front organisational theory and negotiation theory to better Understand what is concealed in the black-box of decision-making and implementation. My empirical material consists of case studies of four different means of environmental control used in Sweden during the 1990s to mitigate the threat of global warming. These are tin enviromnental tax| a licensing trial| municipal energy planning| and technology procurement. Each represents a particular discipline (economic| legal| physical planning| or technological) in which a context (planning or market) and an approach (traditional relay race or alternative process-oriented) are combined. Although each means has its particular niche| some qualities stand out as superior. Such means need to be divisible in space as well as in tinge. It is then easier to get started. Since it is just its easy to deviate from| rather than adhere to| the predetermined course after a while| some incentive must be given to the person in charge of implementation. In other words| the classic proverb of using sticks and carrots is still valid although it is not always taken to heart and practised. (C) 2002 Elsevier Science Ltd. All rights reserved. 5894,2002,3,2,Mitigating the rate and extent of global warming,Mitigation| in the sense of slowing the rate of CO2 emission| can reduce the rate of rise of CO2 and global warming and limit peak CO2 concentration and global warming. However| it will have little effect on the near steady state CO2 concentration and corresponding global warming achieved on a millennial timescale once emissions are negligible and the added carbon has been distributed between the ocean| atmosphere and land. Using a simple model with mid-range climate sensitivity| we estimate that the maximum rate of global warming can be limited to <0.2degreesC/decade by limiting the rate of increase in fossil fuel emissions this century to <0.03 GtC/yr/yr. However| regardless of the emissions pathway| if the known fossil fuel resource of similar to4000 GtC is emitted| CO2 will reach similar to1000 ppmv and the Earth will be warmed by >5degreesC by the end of the millennium. The more carbon emitted| the greater the fraction that remains in the atmosphere| because of positive feedbacks in the carbon cycle-climate system. Less carbon must be emitted to lessen eventual warming. Early consideration should therefore be given to leaving a fraction of fossil carbon unused| and/or to carbon capture and storage. 5821,2002,3,3,Mitigation of N(2)O emissions from grassland by nitrification inhibitor and Actilith F2 applied with fertilizer and cattle slurry,Nitrous oxide (N(2)O) is involved in both ozone destruction and global warming. In agricultural soils it is produced by nitrification and denitrification mainly after fertilization. Nitrification inhibitors have been proposed as one of the management tools for the reduction of the potential hazards of fertilizer-derived N(2)O. Addition of nitrification inhibitors to fertilizers maintains soil N in ammonium form| thereby gaseous N losses by nitrification and denitrification are less likely to occur and there is increased N utilization by the sward. We present a study aimed to evaluate the effectiveness of the nitrification inhibitor dicyandiamide (DCD) and of the slurry additive Actilith F2 on N(2)O emissions following application of calcium ammonium nitrate or cattle slurry to a mixed clover/ryegrass sward in the Basque Country. The results indicate that large differences in N(2)O emission occur depending on fertilizer type and the presence or absence of a nitrification inhibitor. There is considerable scope for immediate reduction of emissions by applying DCD with calcium ammonium nitrate or cattle slurry. DCD| applied at 25 kg ha(-1)| reduced the amount of N lost as N(2)O by 60% and 42% when applied with cattle slurry and calcium ammonium nitrate| respectively. Actilith F2 did not reduce N(2)O emissions and it produced a long lasting mineralization of previously immobilized added N. 2950,2002,4,1,Modeling future climate changes: certainties and uncertainties,Since the middle of the nineteenth century the composition of the Earth atmosphere has begun to change in a manner which is unprecedented over the Quaternary era. The carbon dioxide concentration| for example had been oscillating between extremal values of 180 ppm (during glaciations) and 280 ppm (during interglacial eras). It had stayed almost constant over the last 10 000 years| but has now reached a value of 360 ppm| much of the increase taking place during the last decades. Similarly methane concentration has been multiplied by more than a factor 2| and other gases (nitrous oxides) have also experienced an exponential growth. There is no doubt that this situation is the result of human activities : energy consumption| industrial or agricultural activities| deforestation. As most of these gases have a long residence time in the atmosphere| where they tend to accumulate| we may expect the level of these perturbations to increase strongly throughout the 21st century. To diagnose the possible impact of these trends in terms of climate impact| the only available tools are numerical models. These numerical models constitute in a way virtural planets| where the atmospheric and oceanic flow| the continental hydrology| and their interactions| are represented through physical equations. Models are not a perfect representation of the Earth system| and they will never be. We also cannot expect the climate system to be fully predictable. But models are strongly constrained by conservation equations| they behave in many aspects like the real planet and reproduce quite realistically the mean geographical and seasonal fluctuations of the precipitation| the temperature or the winds as well as some of the most important natural fluctuations at intraseasonal or interannual (El Nino| North Atlantic Oscillation) time scales. So models are useful to describe a range of possible future climates Present projections indicate in all cases| a significant change| with a global surface warming in 2 100 between 2degreesC and 6degreesC : half of the uncertainty is due to the economic projections| half is due to the complex behavior of the climate system (in particular : clouds). It is striking that the lower bound of these estimates already represents an important perturbation. The changes in temperature would induce changes in precipitation rates or areas| in storminess or cyclone tracks - the regional consequences are however difficult to predict in details. We may expect the sea level to rise from 20 to 90 cm. Changes in a more distant future (2 centuries) might be much larger| although such projections are less reliable. An important feature of the changes to come may be their partially unpredictable character : many of the local events accompanying a global climate change will arise as surprises. In that sense the rate of change will be the primary factor of danger. And if it is probably too late to stop climate modification| there is still time to favor a situation where adaptation to its impacts will be easier. 2898,2002,4,4,Modeling regional carbon dynamics and soil erosion in disturbed and rehabilitated ecosystems as affected by land use and climate,The quantification of carbon (C) and nitrogen (N) cycling in ecosystems is important for (a) understanding changes in ecosystem structure and function with changes in land use| (b) determining the sustainability of ecosystems| and (c) balancing the global C budget as it relates to global climate change. A meso-scale study was conducted to determine regional effects of climate change on C and N cycling within disturbed ecosystems. Objectives of the research were to quantify (a) sediment yield| (b) current C storage in vegetation and soils| and (c) soil C efflux from both abandoned and rehabilitated coal surface-mined lands in Ohio. A dynamic model was developed to simulate sediment yield| grassland production| and C and N cycling on surface-mined lands. Evaluation of plant production and soil erosion submodels with data sets from surface-mined lands in the mid-western U.S. resulted in r(2) values of 0.99 and 0.97| respectively. Depending on the initial values of soil organic carbon (SOC)| model simulations estimated that unvegetated surface-mined lands in Ohio yield approximately 441|325 Mg yr(-1) of sediment and emit between 2|000-20|000 Mg yr(-1) of C to the atmosphere from decomposition of SOC. While rehabilitated lands had a higher C efflux rate than barren lands| a positive C sequestration rate of 18.4 Mg km(-2) yr (-1) was estimated as a result of organic matter additions. This sequestion rate increased considerably under projected climate change scenarios| while it decreased when simulated rehabilitated grasslands were harvested for hay. Changes in land use and cover can cause surface-mined lands to be either a net sink or source for C. Successful rehabilitation of mined lands can decrease erosion and promote soil C sequestration| while at the same time providing additional lands for the management of natural resources. 5816,2002,2,3,Modeling studies on the changes of the Subtropical High over the Western Pacific during the last 100 years,Intensity index series of Subtropical High over the Western Pacific was constructed according to modeling results by using of CCM3.6 atmospheric model with climatologically SST forcing for 30 years| and with observed SST forcing from 1900 to 2000. The index series constructed by modeling closely correlated to the observations for 19511999 (c.c. 0.72) and to the statistically reconstructed one for 1900-1950 (c.c. 0.51). The index series for 1900-1999 showed significant 80 a and 40 a periodicity. A minimum of persistence in seasonal variations of the index occurred in Autumn| which was called "Autumn Barrier". It may relate to the "Spring Barrier"| found in the seasonal variations of SST over the Eastern Equatorial Pacific. The increasing trend shown in the index series for the 20th century may associate with the global warming caused by enhancement of greenhouse effect. 2859,2002,2,3,Modeling the effects of global climatic change at the ecotone of boreal larch forest and temperate forest in Northeast China,The dynamics of the forest at the ecotone of the boreal forest and temperate forest in Northeast China were simulated using the adapted gap model BKPF under global climatic change (GFDL scenario) and doubled CO2 concentrations at 50 years in the future. The response of tree species and species with similar biological characteristics under global climate change and double CO2 concentrations were based on biophysical limits of the tree species in the area and their biological competition. The results showed that after 50 years the stand density and LAI (leaf area index) of the forest growing from a clear-cut would not be significantly different from those under current conditions. Stand productivity would increase about 7%| and stand aboveground biomass would increase 15%. However| the stand density of the current mature forest would be reduced by more than 20%. The stand would be dominated by Quercus mongolica Fisch.| Populus davidiana Dode.| Betula spp. and other broadleaved tree species| and Quercus mongolica would account for about 50% of the total density. The stand biomass would be reduced by more than 90%. Quercus mongolica would comprise about 57% of the total stand biomass. The stand productivity would not change significantly| but it would be comprised mainly of Quercus mongolica| Populus davidiana| Betula spp. The current stand height would decrease slightly. The stand LAI would decline dramatically| moreover| Quercus mongolica would comprise about 50% of the stand LAI. 2879,2002,2,3,Modelling regional responses by marine pelagic ecosystems to global climate change,Current coupled ocean-atmosphere model (COAM) projections of future oceanic anthropogenic carbon uptake suggest reduced rates due to surface warming| enhanced stratification| and slowed thermohaline overturning. Such models rely on simple| bulk biogeochemical parameterisations| whereas recent ocean observations indicate that floristic shifts may be induced by climate variability| are widespread| complex| and directly impact biogeochemical cycles. We present a strategy to incorporate ecosystem function in COAM's and to evaluate the results in relation to region-specific ecosystem dynamics and interannual variability using a template of oceanic biogeographical provinces. Illustrative simulations for nitrogen fixers with an off-line multi-species| functional group model suggest significant changes by the end of this century in ecosystem structure| with some of the largest regional impacts caused by shifts in the areal extent of biomes. 5826,2002,4,4,New observational evidence for global warming from satellite,[1] Accurate measurements of surface radiative temperature| i.e. skin temperature| would be more directly interpretable in terms of the surface response to increase of greenhouse gases than the more conventional screen temperatures. Such measurements have not previously been attempted because of the difficulties of converting existing observations into a meaningful measurement. We have developed procedures for removing the effects of changing satellite orbits and cloud contamination from skin temperatures estimated from AVHRR channels 4 and 5| and so provide a first estimate of the trends of land surface skin temperature over the last two decades. The estimated land temperature increase is not only much greater than that for the atmosphere but also apparently somewhat larger than the estimates of surface air temperature increase from in situ measurement. 2933,2002,3,3,New renewable energy developments and the climate change issue: a case study of Norwegian politics,It is widely agreed that the search for cleaner energy technologies is central to any long-term response to the threat of global climate change. Many countries are thus promoting the adoption of new renewable energy (NRE) sources and technologies within the context of energy and climate change policies. The scope of this paper is to unfold linkages between public policies and NRE developments using Norway as a case in point. The aims are firstly to assess the impacts of policy design and public priorities in terms of technology and industrial development dynamics| and secondly to discuss the role attributed to the climate change issue. The primary conclusion is that in spite of long-lasting public efforts| NRE sources represent only a pitiable fraction of the energy produced| delivered| and consumed in Norway. and only modest industrial development dynamics have taken place. Among the most important reasons for this poor outcome tire (i) weak demand-side policies| (ii) fluctuating patterns in public priorities. and (iii) low electricity prices. The Norwegian experience substantiates claims that effective public strategies should be firmly based upon long-term commitments. employ a combination of policies and measures conducive to technical change and innovation. and be capable of guarding against path dependence. (C) 2002 Published by Elsevier Science Ltd. 2890,2002,3,3,Nitrous oxide emissions from an ultisol of the humid tropics under maize-groundnut rotation,Nitrous oxide (N2O) contributes to global climate change and agricultural soils seem to be the major source. Lack of information led to this study on the influence of different amounts and sources of nitrogen on N2O emission from a maize (Zea mays L.)-groundnut (Arachis hypogae L.) crop rotation in an Ultisol of the humid tropics. The treatments were: inorganic N + crop residues (NC)| inorganic N only (RN)| and half of inorganic N + crop residues + chicken manure (NCM). The corresponding amount of N applied was 322| 180| and 400 kg ha(-1) yr(-1)| respectively. The N2O emissions depended on the amounts and types of N. A maximum peak (9889 +/- 2106 muLg N2O-N m(-2) d(-1)) was detected at 2 wk before maize sowing amended with chicken manure| showing a persistent influence on N transformations and N2O release. The mineral N from either applied source became low by 2 to 4 wk| coinciding with the small N2O fluxes or its consumption to a few isolated instances. The N2O flux significantly correlated with the mineral N and water-filled pore spaces. The direct annual N2O emission was 3.94 +/- 0.23| 1.90 +/- 0.08| and 1.41 +/- 0.07 kg N2O-N ha(-1) from the NCM| NC| and RN treatments| respectively. The corresponding N2O-N loss of the applied N plus N fixed by groundnut was 0.83|0.49| and 0.59%. Overestimations of direct annual N2O emission using the Intergovernmental Panel on Climate Change (IPCC) methodology suggest a location-specific emission factor for variable N sources to be considered. 2848,2002,2,4,No evidence for adaptation of two Polygonum viviparum morphotypes of different bulbil characteristics to length of growing season: abundance| biomass and germination,The high degree of habitat heterogeneity and habitat fragmentation in arctic ecosystems may support a high genotypic and ecotypic variability. This may buffer the survival of plant species threatened by global climate change| which affects the Arctic more strongly than other ecosystems. Here| we assessed if two morphotypes of Polygonum viviparum (characterised by different colours of their bulbils) differ in their abundance along a snowmelt gradient| if their biomass allocation patterns are influenced differentially by environmental variables| and if the temperature dependency of bulbil germination differs between morphotypes. We found slight differences in the effect of timing of snowmelt on abundance of the morphotypes| which seem to have little ecological relevance. Total biomass and biomass allocation were similar between morphotypes and were negatively correlated with soil-water content. Bulbil germination (the onset of growth of the bulbil) was assessed over a temperature range from 2 to 25 C and results indicate an earlier (maximum of 5 days) "germination" of one morphotype| but final bulbil germination (> 80%) and bulbil-germination rate were similar for both types. Bulbil germination was weakly temperature dependent| with faster emergence at higher temperatures. Overall| our results could provide no convincing evidence for differences between the two examined morphotypes that could be of ecological relevance with respect to anticipated climate change in the Arctic. 5920,2002,2,4,Nutrient loading and retention in lakes of the Jorka river system (Masurian Lakeland| Poland): Seasonal and long-term variation,The nutrient (TP| N-NO3| TKN - Kjeldhal nitrogen) loading to lakes (from river| precipitation| direct catchment) and in-lake retention were calculated for five successive lakes of the river-lake system typical of the mosaic| hilly lake-land region (the Jorka system| Masurian Lakeland). The annual values of loading for TP and TN were mostly not higher than 1.0 and 15.0 g m(-2) lake area| respectively and rather low compared to other river-lake systems in the lakeland region. However| these values as well as nutrient in-lake retention decreased in 1997-1998 (warm and dry years) compared with 1978 and 1996| together with the decrease in discharge and exchange rate of lake water. In selected cases the retention of TP and TKN became negative which means that the lake functioned as the source of nutrients for downstream fragments of the system. The retention of nitrate-nitrogen was usually positive - lakes remained effective sites for its removal (denitrification). The possible changes in functioning of small catchments and chains of shallow| eutrophic lakes under the conditions of global warming are discussed. 5751,2002,4,4,Observationally based assessment of polar amplification of global warming,[1] Arctic variability is dominated by multi-decadal fluctuations. Incomplete sampling of these fluctuations results in highly variable arctic surface-air temperature (SAT) trends. Modulated by multi-decadal variability| SAT trends are often amplified relative to northern-hemispheric trends| but over the 125-year record we identify periods when arctic SAT trends were smaller or of opposite sign than northern-hemispheric trends. Arctic and northern-hemispheric air-temperature trends during the 20th century (when multi-decadal variablity had little net effect on computed trends) are similar| and do not support the predicted polar amplification of global warming. The possible moderating role of sea ice cannot be conclusively identified with existing data. If long-term trends are accepted as a valid measure of climate change| then the SAT and ice data do not support the proposed polar amplification of global warming. Intrinsic arctic variability obscures long-term changes| limiting our ability to identify complex feedbacks in the arctic climate system. 2937,2002,4,3,Observed and projected climate change in Taiwan,This study examined the secular climate change characteristics in Taiwan over the past 100 years and the relationship with the global climate change. Estimates for the likelihood Of future climate changes in Taiwan were made based on the projection from the IPCC climate models. In the past 100 years| Taiwan experienced an island-wide warming trend (1.0-1.4degreesC/100 years). Both the annual and daily temperature ranges have also increased. The warming|e-scale circulation in Taiwan is closely connected to a large-scale circulation and SAT fluctuations| such as the "cool ocean warm land" phenomenon. The water vapor pressure has increased significantly and could have resulted in a larger temperature increase in summer. The probability for the occurrence of high temperatures has increased and the result suggests that both (fie mean and variance in the SAT in Taiwan have changed significantly since the beginning of the 20th century. Although| as a whole| the precipitation in Taiwan has shown a tendency to increase in northern Taiwan and to decrease in southern Taiwan in the past 100 years| it exhibits a more complicated spatial pattern. The changes occur mainly in either the dry or rainy season and result in an enhanced seasonal cycle. The changes in temperature and precipitation are consistent with the weakening of the East Asian monsoon. Under consideration of both the warming effect from greenhouse gases and the cooling effect from aerosols| all projections from climate models indicated a warmer climate near Taiwan in the future. The projected increase in the area-mean temperature near Taiwan ranged from 0.9-2.7degreesC relative to the 1961-1990 averaged temperature| when the CO2 concentration increased to 1.9 times the 1961-1990 level. These simulated temperature increases were statistically significant and can be attributed to the radiative forcing associated with the increased concentration of greenhouse gases and aerosols. The projected changes in precipitation were within the range of natural variability for all five models. There is no evidence supporting the possibility of precipitation changes near Taiwan based on the simulations from five IPCC climate models. 5701,2002,2,4,Observed changes in seasons: An overview,Within the last decade the study of phonology has taken on a new legitimacy in the area of climate change research. A growing literature reveals that a change in the timing of natural events is occurring in a wide range of locations and affecting a wide tango of species. Changes in spring have been those most commonly reported| with the emphasis on an advance in spring linked to an increase in temperature. Detection of change in autumn is hampered by a smaller pool of available data| events that are harder to define (such as leaf coloration)| and various influencing environmental factors triggering autumnal phases. Despite this| the general pattern may be towards a delay in autumn. Plant| animal and abiotic responses| especially in spring| are quite similar. Thus| it would appear that winter is being squeezed at both ends| and this effect| of increasing the growing season| should become more pronounced in the face of predicted global warming. Copyright (C) 2002 Royal Meteorological Society. 2850,2002,2,4,Odonata records from Nayarit and Sinaloa| Mexico| with comments on natural history and biogeography,Although the odon. fauna of the Mexican state of Nayarit has been considered well-known| a 7-day visit there in Sept. 2001 resulted in records of 21 spp. new for the state| bringing the state total to 120 spp.| fifth highest in Mexico. Records from a 2-day visit in Aug. 1965 are also listed| many of them the first specific localities published for Nayarit| and the first records of 2 spp. from Sinaloa are also listed. The biology of most neotropical spp. is poorly known| so natural-history notes are included for many spp. A storm-induced aggregation and a large roost of dragonflies is described. The odon. fauna of Nayarit consists of 2 primary elements: a large number of neotropical spp. reaching their northern known limits| and a montane fauna of the drier Mexican Plateau. At least 57 spp. of tropical origin reach their northern distribution in the western Mexican lowlands in or N of Nayarit| and these limits must be more accurately defined to detect the changes in distribution that may be taking place with global climate change. 5895,2002,2,4,On climatic fluctuations and environmental changes of the Indo-Gangetic Plains| India,Paralleling the Southern Himalayan Province| the Indo-Gangetic Plains region (IGPR) of India (geographical area similar to6|00|000 km(2)) is very important for the food security of South Asia. Due to numerous factors in operation there is widespread apprehension regarding sustainability of fragile ecosystems of the region. Literature provides detailed documentation of environmental changes due to different factors except climatic. The present study is intended to document the instrumental-period fluctuations of important climatic parameters like rainfall amounts (1829-1999)| severe rainstorms (1880-1996) and temperature (1876-1997) exclusively for the IGPR. The summer monsoon rainfall over western IGPR shows increasing trend (170 mm/100-yr| significant at 1% level) from 1900 while over central IGPR it shows decreasing trend (5 mm/100-yr| not significant) from 1939 and over eastern IGPR decreasing trend (50 mm/100-yr| not significant) during 1900-1984 and insignificant increasing trend (480 mm/100-yr| not significant) during 1984-1999. Broadly it is inferred that there has been a westward shift in rainfall activities over the IGPR. Analysis suggests westward shift in the occurrence of severe rainstorms also. These spatial changes in rainfall activities are attributed to global warming and associated changes in the Indian summer monsoon circulation and the general atmospheric circulation. The annual surface air temperature of the IGPR showed rising trend (0.53degreesC/100-yr| significant at 1% level) during 1875-1958 and decreasing trend (-0.93degreesC/100-yr| significant at 5% level) during 1958-1997. The post-1958 period cooling of the IGPR seems to be due to expansion and intensification of agricultural activities and spreading of irrigation network in the region. Lateral shift in the river courses is an environmental hazard of serious concern in the IGPR. In the present study it is suggested that meteorologic factors like strength and direction of low level winds and spatial shift in rainfall/climatic belt also play a significant role along with tectonic disturbances and local sedimentological adjustments in the vagrancy of the river courses over the IGPR. 5838,2002,2,4,On the adaptability of Norway spruce (Picea abies (L.) Karst.) to the projected change of climate in Germany,It has been predicted that in the coming decades the global climate will get warmer and in some regions dryer. Global warming may influence the genetic structure of forest tree populations. This paper presents a simulation study on possible effects of an increasing annual mean temperature and decreasing precipitation during the growing season on the genetic structure characterised by inventories of six isozyme gene loci in provenance trials of Norway spruce (Pirea abies (L.) Karst.). The data for parameterising the model were taken from a trial on 25-year-old Norway spruce. From the data a virtual stand was generated to simulate growth over a period of 75 years at seven sites with varying environmental conditions. The tree growth simulator SILVA 2.2 was run with two scenarios (I. natural mortality only; II. natural mortality and thinning from above). The results of the simulation runs were linked with the isozyme data of the trees as investigated in the trees that were selected for generating the virtual population. In the simulated populations at the age of 100 allele and genotype frequencies were determined. Based on the isozyme data calculations of various measures of genetic multiplicity| heterozygosity| genetic diversity| and genetic differentiation were performed for each simulation run. At the age of 100 years three growth parameters|how large differentiation between sites. Such a separation cannot be found for the genetic parameters as assessed by isozyme gene markers. However| most of the eight genetic parameters differ between sites. Significant differences arc calculated for four genetic parameters in scenario I and for six genetic parameters in scenario II. This result obtained by a new approach| calls for additional studies where more initial populations with different characteristics are tested in various scenarios and with different types of markers. 5933,2002,5,3,On the nature of methane gas-hydrate dissociation during the Toarcian and Aptian oceanic anoxic events,The magnitude and timing of a major rapid negative carbon-isotope excursion recorded in marine and terrestrial matter through the Early Toarcian (Early Jurassic) and Early Aptian (Early Cretaceous) oceanic anoxic events (OAEs) have been proposed to be the result of large methane gas-hydrate dissociation events. Here| we develop and evaluate a global carbon-isotope mass-balance approach for determining the responses of each component of the exogenic carbon cycle (terrestrial biosphere| atmosphere and ocean). The approach includes a dynamic response of the terrestrial carbon cycle to methane-related CO(2) increases and climatic warming. Our analyses support the idea that both the Early Toarcian and Early Aptian isotopic curves were indicative of large episodic methane releases (similar to5000 and similar to3000 Gt respectively) promoting warm 'greenhouse' conditions in the Mesozoic. These events are calculated to have increased the atmospheric CO(2) concentration by similar to900 and similar to600 ppmv respectively and land surface temperatures by 2.5degrees to 3.0degreesC. However| we show that much of the methane released from oceanic sediments is rapidly sequestered by terrestrial and marine components in the global carbon cycle| and this effect strongly attenuated the potential for ancient methane gas-hydrate dissociation events to act as major amplifiers in global warming. An increase in oceanic carbon sequestration is consistent with the deposition of globally distributed black shales during these OAEs. Our analyses point to the urgent need for high-resolution marine and terrestrial carbon-isotope records to better characterize the nature of the Toarcian and Aptian events and improve our interpretation of their consequences for the global carbon cycle. 5749,2002,3,3,Optimizing grain yields reduces CH4 emissions from rice paddy fields,Microbial production in anoxic wetland rice soils is a major source of atmospheric CH4| the most important non-CO2 greenhouse gas. Much higher CH4 emissions from well managed irrigated rice fields in the wet than in the dry season could not be explained by seasonal differences in temperature. We hypothesized that high CH4 emissions in the wet season are caused by low grain to biomass ratios. In a screenhouse experiment| removing spikelets to reduce the plants' capacity to store photosynthetically fixed C in grains increased CH4 emissions| presumably via extra C inputs to the soil. Unfavorable conditions for spikelet formation in the wet season may similarly explain high methane emissions. The observed relationship between reduced grain filling and CH4 emission provides opportunities to mitigate CH4 emissions by optimizing rice productivity. 2851,2002,5,4,Oxygen isotope evidence for progressive uplift of the Cascade Range| Oregon,Oxygen isotope compositions of fossil equid teeth in the Cascade rainshadow reveal a similar to5parts per thousand decrease in mean delta(18)O since 27 Ma. Isotopic changes are inconsistent with expected effects from global climate change because: (a) the expected isotopic shift to tooth delta(18)O values due to global climate change (similar to1parts per thousand) is much smaller than the observed shift| (b) predicted and observed isotopic trends are opposite for Oligocene vs. Miocene samples| and (c) average compositions and ranges in compositions remained unchanged for samples from before and after major global cooling in the mid-Miocene. Accounting for a decrease in relative humidity of at least 15%| we infer a topographically driven secular shift in the delta(18)O value of rainwater of 6-8parts per thousand since the late Oligocene| which is approximately equivalent to the modem-day difference in delta(18)O values of precipitation and surface waters across the central Cascades. Rise of the central Cascades apparently occurred monotonically over the last 27 Ma| with a hiatus between similar to15.4 and 7.2 Ma| possibly related to eruption of the Columbia River Basalts. Progressive volcanic accumulation over tens of millions of years best explains the data| rather than a short-lived uplift event. Paleoseasonality| as inferred from isotope zoning and intertooth variability| decreased dramatically from 7-9parts per thousand at 15.4-7 Ma to similar to3parts per thousand at 3 Ma| then increased to 6-8parts per thousand today. The cause of the decrease in seasonality at 3 Ma may reflect either brief warming during the mid-Pliocene within the context of global tectonic reorganization| or consumption by equids of water from an isotopically buffered Lake Idaho. (C) 2002 Elsevier Science B.V. All rights reserved. 5706,2002,3,4,Partial discharge and breakdown mechanisms in ultra-dilute SF6 and PFC gases mixed with N-2 gas,Because of the high global warming potential of SF6 gas| research on alternative gases for electrical insulation with a lower environmental impact is essential. Gas mixtures composed of electronegative gases and N-2 gas have the advantage of the reduction of the amount of SF6 gas and of utilizing the synergistic effect in electrical insulation performance. We investigated the partial discharge (PD) and breakdown (BD) characteristics of SF6/N-2 and PFC (C3F8/N-2 and C2F6/N-2) gas mixtures under non-uniform electric field conditions| by changing the dilute content of electronegative gases. As a result| the synergistic effect in SF6/N-2 gas mixtures was verified to be higher than that in PFC/N-2 gas mixtures. The physical mechanism from PD inception to BD was discussed with consideration of the difference in electronegativity of SF6 and PFC. gases. Furthermore| we found that PD inception and PD-to-BD mechanisms changed at a content of 10 ppm for SF6 due to the electron attachment activity of SF6 gas. The change in the PD and BD mechanisms in C3F8/N-2 and C2F6/N-2 gas mixtures appeared at 0.1% content for C3F8 and at 1% content for C2F6. 5785,2002,3,4,Performance analysis of polymer-electrolyte water electrolysis cell at a small-unit test cell and performance prediction of large stacked cell,Recently the hydrogen energy system has been proposed as a countermeasure for the depletion of fossil fuel and global warming. The polymer electrolyte electrolysis cell (PEEC) can efficiently produce pure hydrogen under high current density. To design a PEEC properly and to optimize its operating conditions we have measured and analyzed the PEEC performance. Using measured overpotentials we have made a two-dimensional simulation code for PEEC. Calculated results show that the profile of current density and temperature are constant along the water flow direction| because the exothermic heat from overpotentials is almost canceled out by the endothermic heat of both entropy change and evaporation| and by heat transfer to the constant-temperature separators| resulting in a constant water-electrolyzing potential along the flow direction. The current densities measured at a segmented-electrode cell agreed well with the calculated values. By applying this simulation code to a large unit-cell with adiabatic boundary conditions| we have predicted the performance of a large stacked PEEC having an electrode length of 1 m. The predicted cell temperature and current density increase only a little along the flow direction. Under operating conditions with high pressure| the endothermic heat of water evaporation decreases greatly and the cell temperature is apt to increase downstream compared to the atmospheric operation. (C) 2002 The Electrochemical Society. 5800,2002,3,3,Performance evaluation of hybrid (wind/solar/diesel) power systems,Depleting oil and gas reserves| combined with the growing concerns of global warming| have made it inevitable to seek alternative/renewable energy sources. The integration of renewables such as solar and wind energy is becoming increasingly attractive and is being used widely| for substitution of oil-produced energy| and eventually to minimize atmospheric degradation. The literature shows that commercial/residential buildings in Saudi Arabia consume an estimated 10-40% of the total electric energy generated. In the present investigation| hourly wind-speed and solar radiation measurements made at the solar radiation and meteorological monitoring station| Dhahran (26degrees32' N| 50degrees13' E)| Saudi Arabia| have been analyzed to investigate the feasibility of using hybrid (wind+solar+diesel) energy conversion systems at Dhahran to meet the energy needs of twenty 2-bedroom houses. The monthly average wind speeds for Dhahran range from 4|1 to 6.4 m/s. The monthly average daily values of solar radiation for Dhahran range from 3.6 kWh/m(2) to 7.96 kWh/m(2). The performance of hybrid systems consisting of different rated power wind farms| photovoltaic (PV) areas| and storage capacities together with a diesel back-up are presented. The monthly average daily energy generated from the above hybrid system configuration has been presented. The deficit energy generated from the back-up diesel generator and the number of operational hours of the diesel system to meet a specific annual electrical energy demand of 702|358 kWh have also been presented. (C) 2002 Elsevier Science Ltd. All rights reserved. 2860,2002,4,4,Permafrost science and secondary education: direct involvement of teachers and students in field research,Permafrost and periglacial geomorphology are absent from the science curriculum in most secondary schools in the United States. This is an unfortunate situation given the recent increases in development and environmental concerns in northern latitudes and high-mountain areas| and the interesting examples of basic scientific principles found in the history of research on periglacial geomorphology and permafrost| In 1997 and 1998| a University of Delaware research group studying permafrost and periglacial geomorphology in northern Alaska participated in the National Science Foundation's (NSF) Teachers Experiencing the Antarctic and Arctic (TEA) Program| In each of these years| a high school teacher and a student traveled as part of the research team to the North Slope of Alaska. They learned about the landscape| collected active-layer thickness and temperature measurements| and assisted in data analysis. Results from studies of active-layer thickness variability and ground temperature contributed to a series of long-term observations and international research on the impacts of global climate change. Since their expeditions. the teachers have shared their experiences with their classrooms and communities in several ways| including public lectures and the Internet. Classroom activities are available to the public through the TEA web site (The exchange of carbon dioxide between the atmosphere| biosphere and pedosphere is an important consideration when assessing agricultural and environmental management or policy decisions and their relationship to climate change. Field experimentation is the best way to gather data| but experimental data are specific to the management| soils and climate that represent the research site. Inadequate field data exist to address all management options across all soil types and climates. We have used the Intergovernmental Panel on Climate Change inventory approach to estimate changes in soil carbon storage resulting from various land use and management options. We generate a regional assessment of the relative impact of implementing changes in agricultural management on soil carbon storage. For each agricultural region of the United States| we present an estimated annual change in soil carbon storage for each management option. Results should prove especially useful in evaluating management options and tradeoffs.
2935,2002,2,4,Predicting life-cycle adaptation of migratory birds to global climate change,Analyses of long-term data indicate that human-caused climatic changes are affecting bird phenology in directions consistent with theoretical predictions. Here| we report on recent trends in the timing of spring arrival and egg laying found within a western European Pied Flycatcher Ficedula hypoleuca population. Mean egg laying date has advanced over the past 20 years in this population. The advancement in egg laying date was stronger than the advancement of spring arrival| suggesting that Pied Flycatchers are changing these stages of their annual cycle at different rates. It could be shown that selection for earlier breeding had increased. Hence| the observed adjustment in laying date did not match the advancement of spring. Our findings raise general questions about the adaptability of migratory birds to rapid environmental changes. Adaptive advancement of reproduction in response to increasing spring temperatures and to the concomitant advancement of food supply could be held back| because annual breeding and migration cycles are controlled primarily by endogenous rhythms and photoperiodic cues which do not relate to temperature. Migrants may have several options for arriving earlier on the breeding grounds| including an increase in migration speed| earlier departure from the wintering area or a shortening of migration distance. Changes in migratory behaviour could be accomplished either by phenotypic plasticity or by selection on different genotypes. Although descriptive field data provide compelling evidence for changes in| and possible constraints on| the timing of breeding and migration| their explanatory power in predicting the limits of adaptation remains restricted. We review recent experimental approaches| which explicitly test the relative roles of genetic versus environmental factors in the adaptation of life-cycle timing to global environmental changes. 2902,2002,2,4,Predicting mammal species richness and abundance using multi-temporal NDVI,There is need to map indicators of biodiversity such as species richness and abundance of individuals in order to predict where species loss is occurring. Species richness and abundance have been hypothesized to increase with ecosystem productivity. Moreover| productivity of ecosystems varies in space and time| and this heterogeneity is also hypothesized to influence species richness and abundance of individuals. Ecosystem productivity may be estimated using remotely sensed data| and researchers have specifically proposed the Advanced Very High Resolution Radiometer-Normalized Difference Vegetation Index (AVHRR-NDVI). Interannual average NDVI and its variability (standard deviation) were correlated with large mammal species richness and abundance of individuals at a landscape scale in Kenya. The biodiversity indicators associated negatively with interannual average NDVI and positively with variability of NDVI. Understanding these relationships can help in estimating changes in mammalian species richness and abundance in response to global climate change. 5900,2002,2,4,Prediction of a geographical shift in the prevalence of rice stripe virus disease transmitted by the small brown planthopper| Laodelphax striatellus (Fallen) (Hemiptera : Delphacidae)| under global warming,Global warming may affect crop damage caused by insect pest| by changing the degree of synchronization between pest occurrence and the susceptible stage of crops. The epidemiological system of rice stripe virus disease (RSV disease) transmitted by the small brown planthopper| Laodelphax striatellus (Fallen)| is greatly influenced by synchronization| because the susceptible stage for virus infection is within several weeks after transplanting. We calculated how the area potentially vulnerable to RSV disease will change under future global warming by using the results of the Global Climate Model (GCM) experiments reported by the Intergovernmental Panel on Climate Change. For simplicity| assuming that rice seedlings are transplanted from May to June| we made a map| in which the number of generations of the small brown planthopper on June 1 was plotted by calculating the effective cumulative temperature. The influence of solar radiation was also considered in this calculation. We judged that the area located near the boundary of generations is potentially vulnerable to disease prevalence| because planthoppers are in the adult stage there. Generation maps indicated that the Tohoku and Hokuriku districts| which are major districts of rice production in Japan| might be potentially vulnerable to disease infection under future global warming. 2886,2002,2,4,Predictions of extreme precipitation and sea-level rise under climate change,Two aspects of global climate change are particularly relevant to river and coastal flooding: changes in extreme precipitation and changes in sea level. In this paper we summarize the relevant findings of the IPCC Third Assessment Report and illustrate some of the common results found by the current generation of coupled atmosphere-ocean general circulation models (AOGCMs)| using the Hadley Centre models. Projections of changes in extreme precipitation| sea-level rise and storm surges affecting the UK will be shown from the Hadley Centre regional models and the Proudman Oceanographic Laboratory storm-surge model. A common finding from AOGCMs is that in a warmer climate the intensity of precipitation will increase due to a more intense hydrological cycle. This leads to reduced return periods (i.e. more frequent occurrences) of extreme precipitation in many locations. The Hadley Centre regional model simulates reduced return periods of extreme precipitation in a number of flood-sensitive areas of the UK. In addition| simulated changes in storminess and a rise in average sea level around the UK lead to reduced return periods of extreme high coastal water events. The confidence in all these results is limited by poor spatial resolution in global coupled models and by uncertainties in the physical processes in both global and regional models| and is specific to the climate change scenario used. 5760,2002,2,4,Present state and future of the world's mangrove forests,Mangroves| the only woody halophytes living at the confluence of land and sea| have been heavily used traditionally for food| timber| fuel and medicine| and presently occupy about 181 000 km(2) of tropical and subtropical coastline. Over the past 50 years| approximately one-third of the world's mangrove forests have been lost| but most data show very variable loss rates and there is considerable margin of error in most estimates. Mangroves are a valuable ecological and economic resource| being important nursery grounds and breeding sites for birds| fish| crustaceans| shellfish| reptiles and mammals; a renewable source of wood; accumulation sites for sediment| contaminants| carbon and nutrients; and offer protection against coastal erosion. The destruction of mangroves is usually positively related to human population density. Major reasons for destruction are urban development| aquaculture| mining and overexploitation for timber| fish| crustaceans and shellfish. Over the next 25 years| unrestricted clear felling| aquaculture| and overexploitation of fisheries will be the greatest threats| with lesser problems being alteration of hydrology| pollution and global warming. Loss of biodiversity is| and will continue to be| a severe problem as even pristine mangroves are species-poor compared with other tropical ecosystems. The future is not entirely bleak. The number of rehabilitation and restoration projects is increasing worldwide with some countries showing increases in mangrove area. The intensity of coastal aquaculture appears to have levelled off in some parts of the world. Some commercial projects and. economic models indicate that mangroves can be used as a sustainable resource| especially for wood. The brightest note is that the rate of population growth is projected to slow during the next 50 years| with a gradual decline thereafter to the end of the century. Mangrove forests will continue to be exploited at current rates to 2025| unless they are seen as a valuable resource to be managed on a sustainable basis. After 2025| the future of mangroves will depend on technological and ecological advances in multi-species silviculture| genetics| and forestry modelling| but the greatest hope for their future is for a reduction in human population growth. 5942,2002,3,4,Pressure-mole fraction phase diagrams for CO2-pure water system under temperatures and pressures corresponding to ocean waters at depth to 3000 m,Pressure-mole fraction phase diagrams for the CO2-water system at temperatures between 278.15 and 298.15 K and pressures up to 30 MPa| which correspond to those of ocean waters at depths to 3000 m| are developed based on the literature data and experimental results obtained by the authors. The resultant phase diagrams can serve as a basis for analyzing the phase behavior of liquid CO2 and CO2 hydrate disposed of in the ocean as a means to mitigate global warming. 2922,2002,2,3,Production of allergenic pollen by ragweed (Ambrosia artemisiifolia L.) is increased in CO(2)-enriched atmospheres,Background: The potential effects of global climate change on allergenic pollen production are still poorly understood. Objective: To study the direct impact of rising atmospheric CO(2) concentrations on ragweed (Ambrosia artemisiifolia L.) pollen production and growth. Methods: In environmentally controlled greenhouses| stands of ragweed plants were grown from seed through flowering stages at both ambient and twice-ambient CO(2) levels (350 vs 700 muL L(-1)). Outcome measures included stand-level total pollen production and end-of-season measures of plant mass|| height| and seed production. Results: A doubling of the atmospheric CO(2) concentration stimulated ragweed-pollen production by 61% (P = 0.005). Conclusions: These results suggest that there may be significant increases in exposure to allergenic pollen under the present scenarios of global warming. Further studies may enable public health groups to more accurately evaluate the future risks of hay fever and respiratory diseases (eg| asthma) exacerbated by allergenic pollen| and to develop strategies to mitigate them. 2869,2002,2,4,Projecting impacts of global climate change on the US forest and agriculture sectors and carbon budgets,A multiperiod| regional| mathematical programming model is used to evaluate the potential economic impacts of global climatic change scenarios on the US forest and agricultural sectors| including impacts on forest carbon inventories. Four scenarios of the biological response of forests to climate change (reflected by changes in forest growth rates) are drawn from a national assessment of climate change and are based on combinations of global circulation and ecological process models. These scenarios are simulated in the forest and agricultural sector model and results are summarized to characterize broad impacts of climate change on the sectors. We find that less cropland is projected to be converted to forests| forest inventories generally increase| and that aggregate economic impacts (across all consumers and producers in the sector) are relatively small. Producers' income is most at risk| and impacts of global climate change on the two sectors vary over the 100-year projection period. The forest sector is found to have adjustment mechanisms that mitigate climate change impacts| including interregional migration of production| substitution in consumption| and altered stand management. 5768,2002,3,3,PSA Peugeot Citroen and biofuels,Biofuels are an essential part of PSA Peugeot Citroen environmental policy| which is itself a major strategic axis for the company- from vehicle production to recycling| from air quality to global warming control| and the development of renewables. Since long PSA has integrated vegetable oil derivatives/biofuels in its activities to reach its global objectives of innovation and growth. In France many vehicle fleets have been running with a blend of normal automotive diesel and biodiesel (30%) for over ten years: none of these has encountered any problem related to the fuel. As a car manufacturer PSA is in favor of biofuels when used in blending with conventional petroleum fuels| gasoline and diesel - an approach that has several advantages: A favorable well-to-wheel CO2 balance (as when growing the plant absorbs some CO2)| which contributes to limit global warming. A complementary source of motor fuel to help reduce crude oil (and diesel) imports. A way to support the agricultural sector (by providing a new outlet for their crops| see set-aside lands). Produced from cereals (corn| maize...) or sugar beet| or from vegetable oil plants like rapeseed| sunflower| or soyabean| biofuels are intrinsically renewable energies. Apart from their particularly favorable well-to-wheel balance| which helps fight against global warming| these fuels allow to reduce exhaust emissions from motor vehicles| notably particulates when using methyl esters derived from vegetable oils. 5863,2002,2,4,Quantifying CO2 fluxes from soil surfaces to the atmosphere,Measurements of CO2 fluxes from ground surface of the atmosphere (soil respiration) are needed to quantify biotic and abiotic reaction rates in unsaturated zones and to gain insight into the importance of these processes on global warming. The use of three techniques (dynamic closed chambers| static chambers| and gradient calculations) to determine soil respiration was assessed by measuring fluxes of microbially produced CO2 from an unsaturated mesocosm (2.4 m dia. x 3.2 m thick) and two unsaturated minicosms (0.58 m dia. x 1.2 m thick)| one maintained at 18-23 degreesC (HT) and the other at 5 degreesC (LT). By injecting known and constant CO2 fluxes into the bottom of the HT minicosm and measuring the resulting fluxes| it was shown that the dynamic closed chamber (DCCS) technique yielded accurate measurements of fluxes over the range observed from natural unsaturated media. Over this same range| results showed that the concentration gradient method yielded reasonable estimates of fluxes but its accuracy was limited by uncertainties in both the concentration gradient and the gaseous diffusion coefficient in the soil atmosphere. The static chamber method underestimated the actual flux at higher CO2 fluxes and when adsorption times of >24 h were used. (C) 2002 Elsevier Science B.V. All rights reserved. 2931,2002,4,3,R-134a emissions from vehicles,We report the first study of R-134a (also known as HFC-134a and CF3CFH2) refrigerant leakage from air conditioning (AC) systems of modern vehicles. Twenty-eight light duty vehicles from five manufacturers (Ford| Toyota| Daimler Chrysler| General Motors| and Honda) were tested according to the USEPA (Federal) extended diurnal test procedure using the Sealed Housing for Evaporative Determination (SHED) apparatus. All tests were conducted using stationary vehicles with the motor and air conditioning system turned off. R-134a was measured using gas chromatography (GC) with a flame ionization detector (FID). All vehicles exhibited measurable R-134a leakage over the 2-day diurnal test. Leak rates of R-134a ranged from 0.01 to 0.36 g/day with an average of 0.07 +/- 0.07 g/day. When combined with leakage associated with vehicle operation| servicing| and disposal we estimate that the lifetime average R-134a emission rate from an AC equipped vehicle is 0.41 +/- 0.27 g/day (the majority of emissions are associated with vehicle servicing and disposal). Assuming that the average vehicle travels 10 000 miles per year we Estimate that the global warming impact of R-134a leakage from an AC equipped vehicle is approximately 4-5% of that of the CO2 emitted by the vehicle. The results are discussed with respect to the contribution of vehicle emissions to global climate change. 5947,2002,2,4,Rapid sea-level rise in the Gulf of Maine| USA| since AD 1800,Two sea-level records from salt marshes in coastal Maine are derived from foraminiferal analyses and AAIS C-14| Pb-210| Cs-137 and pollen chronology| Both records cover the period from AD 800 until the present and show corresponding patterns of sea-level change when corrected for trends which could accommodate millennial-scale isostatic adjustments. The records provide a detailed sea-level chronology for the last few centuries and thus link the instrumental (tide-gauge) record with the long-term geological record of sea-level change. Results show that sea level was relatively stable between AD 800 and 1300 and reached a lowstand around AD 1800| which was preceded by an oscillation in the eighteenth century. Since AD 1800| sea levels in the Gulf of Maine have risen by 0.3-0.4 m. The onset of this rise corresponds with regional climatic warming and could be interpreted as thermal expansion of the Gulf of Maine and North Atlantic sea surface. Sea-level rise possibly slowed temporarily during the mid-nineteenth century| but twentieth-century rates are unprecedented in the last millennium and correspond with hemispheric warming. 5836,2002,4,4,RBS analysis of trace gas uptake on ice,Uptake and reaction of acidic trace gases (HCl| HBr| SO2|...) on atmospheric aerosols is of key interest to environmental problems such as ozone depletion and global warming. While the importance of these reactions is well established| the physical mechanisms involved are subject to current research and scientific controversy. The present paper demonstrates the use of Rutherford backscattering spectroscopy (RBS) to profile elements such as bromine and sulfur on ice surfaces and the application of RBS to study liquid sulfuric acid. The experimental chamber needed for these measurements is described in this paper. (C) 2002 Elsevier Science B.V. All rights reserved. 5873,2002,2,4,Reactive nitrogen and human health: Acute and long-term implications,Reactive-nitrogen (Nr) has a wide variety of beneficial and detrimental effects on human health. The most important of the beneficial effects are increasing global and regional food supplies and increased nutritional quality of available foods. However| lack of adequate dietary intake of amino acids and proteins is a serious cause of malnutrition when food supplies are inadequate because of poverty| drought| floods| wars| and displacements of people as refugees. There is sufficient| though limited| quantitative data indicating that increased circulation of Nr in the environment is responsible for significant human health effects via other exposure pathways. Nr can lead to harmful health effects from airborne occupational exposures and population-wide indoor and outdoor air pollution exposures to nitrogen dioxide and ozone. Nr can also affect health via water pollution problems| including methemoglobinemia from contaminated ground water| eutrophication causing fish kills and algal blooms that can be toxic to humans| and via global warming. The environmental pollutants stemming from reactive nitrogen are ubiquitous| making it difficult to identify the extent to which Nr exerts a specific health effect. As all populations are susceptible| continued interdisciplinary investigations are needed to determine the extent and nature of the beneficial and harmful effects on human health of nitrogen-related pollutants and their derivatives. 5855,2002,2,4,Realized and potential climate niches: a comparison of four Rhododendron tree species,Aim This study aims to evaluate the hypothesis that there is no difference between the realized and the ex-situ niches of four selected Rhododendron tree species. If the hypothesis is rejected| the aim is: (1) to evaluate whether the magnitude of discrepancy between the two types of niche is related to competition or external constraint| and (2) to identify which niche dimension is expanded (cold and/or warm limits) and to discuss it in relation to the assumption behind the biogeographical projections related to global warming. Location The four target species (Rhododendron arboreum Sm.| R. campanulatum D. Don| R. barbatum Wall.| and R. wallichi Sm.) are common evergreen broad-leaved trees in the central Himalayas. Their realized niches are based on data from the elevation-temperature gradient in Nepal (1000-5000 m a.s.l.). The ex-situ data are from botanical gardens and arboreta mainly located in the northern hemisphere (n=43). Method Binary data on these taxa were obtained from 707 geocoded herbarium specimens (elevation and UTM location) and from two elevation transects in Nepal (n =194 plots). Climate conditions from ex-situ locations for each taxon were compared with their realized climate ranges with respect to (i) mean annual temperature (MAT)| (ii) mean minimum temperature of the coldest month (MINCM)| (iii) mean maximum temperature of the warmest month (MAXWM)| and (iv) moisture index (MI). Realized optima were estimated by Generalized Linear Models (GLM)| and its non-parametric extension| Generalized Additive Models (GAM)| were used to estimate the realized niches. Results All target species have ex-situ individuals outside the realized climate niche| but the number is much higher for maximum and minimum variables than for MAT. The most dominant species (in-situ )| R. arboreum| had very few individuals outside its realized range| indicating congruence between its ex-situ and realized niches. The other taxa had many individuals outside the warm end of their realized temperature ranges| but almost none beyond the cold end of their ranges. All target taxa occur in common gardens under warm temperate conditions| but only R. arboreum grows in the warm temperate zone in the Himalayas. This trend at the warm end of the gradient is interpreted as a result of biotic exclusion. Main conclusion The results demonstrate that an extreme cold temperature may represent an absolute boundary for tree species' survival| whereas warm temperatures do not. This is in agreement with the hypothesis that several tree species may survive global warming in-situ because of high temperature tolerance| but its effect on regeneration is uncertain. In lieu of this there may be a significant time lag between change in climate and transient tree species distribution. Thus the effect of global warming on tree species distribution may be very difficult to predict. 5820,2002,2,4,Recent evolution of surge-related events in the northern Adriatic area,The recent increase in the frequency of coastal flooding in Venice mainly depends on loss of land elevation (subsidence and eustasy) and man-induced hydrodynamic changes in the lagoon area| but can also be strengthened in the near future by changes in climate. In this paper| after a short review of recent changes in the relative mean and maximal levels of the sea and their causes| the main meteorological factors (atmospheric pressure and winds of sirocco and bora)| which produce sea surges in the Gulf of Venice| are identified statistically. The recent evolution of these meteorological factors in the Adriatic area shows some favorable trends (the atmospheric pressure is increasing| thus provisionally masking eustatic sea-level rise| and bora is sharply lessening). However| the effects of sirocco| which is increasing in frequency in the mid-Adriatic| seem to be prevailing. On the whole| the frequency of sea surges greater than or equal to5 cm to greater than or equal to30 cm| which are the most frequent| is increasing in the North Adriatic and this implies more "moderately high tide levels"| which are however liable to flood the lowest parts of the city of Venice. Such increase in frequency seems related to recent climatic changes (possibly related to global warming) and may therefore be expected to worsen in the near future. 5930,2002,2,4,Reconciling differences in predictions of temperature response of soil organic matter,Global warming has long been assumed to lead to an increase in soil respiration and| hence| decreasing soil carbon stores. This assumption has been based on short-term studies of litter and soil organic matter incubations. However| some recent studies seem to indicate that soil organic matter is less temperature sensitive than previously thought. We will in this paper use the continuous-quality theory to show that the temperature dependence of decomposition of soil organic matter depends on whether one studies soils at their native temperatures or soils that have been perturbed from their native temperatures. Turnover times of soil organic matter are more sensitive to temperature changes when they are estimated from typical incubation experiments with different temperatures than when they are estimated from soils at their native temperatures because the variation in turnover rate with native soil temperature is not the same as the temperature response of turnover rate of a given soil. This reconciles some seemingly incompatible results in the literature. (C) 2002 Elsevier Science Ltd. All rights reserved. 5807,2002,3,3,Recovery of fluorocarbons in Japan as a measure for abating global warming,The objective of this study is to evaluate the potential for recovering fluorocarbons as measures for the abatement of global warming. In this study. we focused on the three different kinds of fluorocarbons: CFCs. HCFCs and HFCs. and targeted refrigerant use because of the availability of relevant data. We first estimated future fluorocarbon emissions from the targeted appliances: we next compared those emissions in the units of CO2 equivalent to the level of CO2 emissions in 1990 from a quantitative point of view. As the result of this study| it was found that fluorocarbon emissions in 1999 and 2010 would be equal to approximately 7 and 3% of the level of CO2 emissions in 1990 respectively. Moreover. if we implement a 100% recovery rate in every recovery route| we can reduce a large amount of emissions which correspond to approximately 2-5% of the level of CO2 emissions in 1990| even if we take into account the enery-related CO2 emissions by the transportation and decomposition of fluorocarbons. (C) 2002 Elsevier Science Ltd. All rights reserved. 5938,2002,3,4,Refrigeration and the environment - issues and strategies for the future,Worldwide reactions to the debates on global warming and ozone depletion have led to social responses and legislative measures which have serious implications for refrigeration and associated industries. This paper discusses the| problems to be faced| and the ways in which the industry can contribute to meeting the wider global objectives. The discussion considers the choice and availability of working fluids| the increased complexity of using fluid mixtures| and the risk of losing the simplicity in design and construction which was possible with CFC single fluids. Education and training are presented as issues because of the changes in technology. (C) 2001 Elsevier Science Ltd and IIR. All rights reserved. 2925,2002,5,4,Regional lithofacies and pedofacies variations along a north to south climatic gradient during the Last Glacial period in the central Loess Plateau| China,Five lateral sand-loess-palaeosol continua occur within the last glacial sediments of the central Loess Plateau of China along a 500 km north to south climatic gradient. The continua shift southward or northward in concert with desert expansion or contraction| respectively. Lateral lithofacies (desert sand to loess) variations are evident at the north end of the gradient and follow Walther's Law of the correlation of facies. Lateral pedofacies (loess to palaeosol) variations are present near the south end of the gradient| where the climate was warmer and wetter. The lateral stratigraphic changes from sand to loess or loess to soil are driven by variations in the rate of sedimentation along a climatic gradient. Vertical stratigraphic profiles at the north end of the gradient reveal alternating sand and loess beds. In contrast| alternating loess and palaeosols occur within the same stratigraphic interval in the southern Loess Plateau| where dust accretion rates were lower. However| in high resolution studies of climate change vertical profiles of alternating loess and palaeosols (especially weak palaeosols) may not reflect regional or global climate change. Alternating loess and weak palaeosols may reflect local variations in the balance between the rates of dust accretion and pedogenesis. Local fluctuations in either of these rates could result in the presence of time equivalent loess and palaeosols at high resolutions. Thus| some of the high resolution loess-palaeosol alternations may reflect local climatic variation rather than global or hemispherical climate change. 2002 Published by Elsevier Science Ltd. 2895,2002,2,3,Regional ocean climate simulations with a 3D ice-ocean model for the Baltic Sea. Part 1: model experiments and results for temperature and salinity,Sea surface temperatures and salinity profiles in the Baltic Sea have been analyzed under different climate conditions using a 3D coupled ice-ocean model. As a reference| hindcast simulations for the period 1980-93 have been performed using observed three-hourly meteorological forcing fields and observed monthly river runoff. The results are compared with available observations from monitoring stations. The observed Baltic Sea climate is well reproduced by the model. Furthermore| two sets of 9-year time slice experiments have been performed using results from an atmospheric regional climate model as forcing. One of the time slice sets represents pre-industrial greenhouse conditions (control simulation)| and the other set represents a global warming condition with a 150% increase in equivalent CO(2) concentrations (scenario simulation) with lateral boundary conditions from the global atmosphere-ocean general circulation model| HadCM2. To simulate river runoff| a large-scale hydrological model has been applied. As the time slices are too short to properly spin up initial stratification for future climate| salinity is treated as an uncertainty factor. An extreme condition is obtained by integrating the Baltic Sea model for a period of 100 years while assuming that no salt water inflow will occur in the future. Salinity in the Gotland Basin decreases in the surface layer by about 3 to 4 psu and in the bottom layer by about 6 to 6.5 psu. The final quasi-equilibrium is characterized by salinities of 2.8 psu (minimum at the surface) to 6.5 psu (maximum at the bottom). The area averaged annual mean sea surface temperature change between scenario and control run is about 2.3 degreesC. The warming in different seasons is almost the same. The computational effective time slice approach in dynamical downscaling experiments is regarded as a feasible technique to regionalize global climate change experiments in the Baltic Sea. 5801,2002,2,3,Regional ocean climate simulations with a 3D ice-ocean model for the Baltic Sea. Part 2: results for sea ice,The Baltic Sea ice season under changing climate conditions is investigated using a 3D coupled ice-ocean model. Results of multi-year simulations for the period of May 1980 to December 1993 are compared with observations from monitoring stations| ice charts and satellite data. The period 1980-1993 has been selected mainly because of the availability of homogeneous observational data sets for atmospheric variables and river runoff with sufficient quality to force a 3D high resolution Baltic Sea model. The observed seasonal variation of sea ice is well reproduced by the model. Furthermore| two sets of 9-year time slice experiments have been performed using results of an atmospheric regional climate model as forcing| one representing pre-industrial greenhouse conditions (control simulation)| and the other a global warming with a 150% increase of equivalent CO(2) concentration (scenario simulation). At the lateral boundaries of the regional climate model| results of the global atmosphere-ocean general circulation model HadCM2 have been prescribed. In the control run| the mean seasonal cycle of ice cover and its variability is simulated realistically compared to observations| but the seasonal ice cover maximum is shifted in time by about 18 days and the simulated mean melting date is delayed. Mild winters are missing in the relatively short control run. The decrease of mean ice extent in the scenario| compared to the control run| is dramatic| reducing from 210 . 10(9) m(2) to 82 . 10(9) m(2) (a relative change of 61%). However| in all scenario years| ice is still formed in the northernmost basin of the Baltic Sea| the Bothnian Bay. The minimum ice extent is 16 . 10(9) m(2) (for comparison: the area of the Bothnian Bay is about twice as large). The mean number of ice days decreases significantly. In the fast ice zone of the Bothnian Bay the mean ice season is reduced by 40 days. The ice in the scenario run is thinner with less snow on top. In the central Bothnian Bay| mean maximum annual ice thickness is reduced by 25 cm from 54 to 29 cm. Model dependent uncertainties are discussed. 5839,2002,4,4,Regional radiative forcing by line-shaped contrails derived from satellite data,[1] The influence of contrails on the radiation budget depends mainly on their coverage and optical depth. This study derives these parameters from data of the advanced very high resolution radiometer sensor onboard the NOAA 14 satellite for a region over western Europe within 40degrees-56degrees N and 10degreesW-23degrees E during 2 years starting March 1995. The data are classified by an operational contrail detection algorithm with a new evaluation of the detection efficiency. From the classification results| daytime and nighttime coverage by line-shaped contrails over western Europe are derived. The daytime contrail coverage for the analyzed region is 0.7% in the annual mean| 1.0% during winter| and 0.4% during summer. The daytime contrail cover is 3 times higher than the night-time contrail cover. An effective optical depth of the observed contrails is derived from the radiation contrasts in the 11 m m channel for contrails and adjacent pixels. The optical depth in the visible spectral range is computed from these results assuming a previously measured size spectrum of ice crystals. The mean visible optical depth is found to be about 0.1| much smaller than that derived from previous case studies. The average radiative forcing at the top of the atmosphere is computed for the derived contrail cloud cover and optical depth. Here contrails mostly cause positive radiative forcing (heating). Larger heating effects during night and summer get partly compensated through more contrail cover during day and winter. The radiative forcing by contrails in the examined region is similar to0.03 W m(-2)| which is much smaller than was estimated earlier. 5688,2002,2,3,Regional responses of climate in the northwestern Pacific Ocean to gradual global warming for a CO2 quadrupling.,This study investigates the regional responses of a climate model to the gradual increase of atmospheric carbon dioxide at 1% per year compounded for quadrupling. Use of NCAR fully coupled Climate System Model (CSM1.2) is attempted| with special emphasis on the simulated sea-level changes in the neighbouring seas of the northwestern Pacific Ocean with an enhanced resolution. Regional warming and sea level change are higher than global changes. At the time Of CO2 quadrupling| the model predicts a rise in sea level of 19 cm and 25 cm for the globe and the northwestern Pacific Ocean| respectively| while surface air temperature rises are 2.9degreesC and 3.0degreesC for the globe and the northwestern Pacific Ocean| respectively. Based on simulations| climate changes in the Northwestern Pacific Ocean will be more distinctive compared with the global average| mainly due to exceptionally large warming and sea level change near the entrance of the Kuroshio extension. 5707,2002,2,4,Relationships between mean and standard deviation of air temperature: implications for global warming,Using data from the contiguous USA| the relationship between mean and standard deviation of daily air temperature was estimated on a monthly timescale from 1948 to 1997. In general| there is either an inverse relationship or a weak relationship between mean and standard deviation. For both daily maximum and daily minimum air temperature| the inverse relationship is spatially coherent for one-third to two-thirds of the contiguous USA for most months. The inverse relationship also is fairly strong| with typical reductions in standard deviation ranging from 0.2 to 0.5degreesC for every 1degreesC increase in mean temperature. A weaker| direct relationship between mean and standard deviation occurs; in some northern states| primarily during spring and fall months. Using the predominant inverse and weak relationships as historical analogs for future climatic change suggests that interdiurnal variability of air temperature should either decrease or remain unchanged under warming conditions. Although the variability of air temperature may decrease or remain unchanged at most locations in the contiguous USA| the probability of extremely high air temperatures should still increase| depending on the magnitude of changes in mean air temperature and the nature of the variance response. 5781,2002,3,3,Renewable energy sources: The key to a better future,This paper outlines the growing need for energy in the developed and developing countries and the acute population growth| which will exceed 10 billion by the year 2050. It describes the achievement and progress made in hydropower| biomass conversion| geothermal| solar thermal technology| wind energy conversion| and the increasing usage of photovoltaics. The paper also addresses the barriers and problems facing renewable energy users and producers. It is evident that global warming is setting in and is going to change the climate as well as the terrain of many countries unless drastic measures are taken. The recent Kyoto meeting emphasized the importance of limiting CO2 emissions and abiding by some form of agreement to reduce emissions. The present study concludes that renewable energy penetration into the energy market is much faster than was expected in recent years and by 2030| 15-20% of our prime energy will be met by renewable energy. 5709,2002,2,4,Response of an allergenic species Ambrosia psilostachya (Asteraceae)| to experimental warming and clipping: Implications for public health,We examined the responses of an allergenic species| western ragweed (Ambrosia psilostachya DC.)| to experimental warming and clipping. The experiment was conducted in a tallgrass prairie in Oklahoma| USA| between 1999 and 2001. Warming increased ragweed stems by 88% when not clipped and 46% when clipped. Clipping increased ragweed stems by 75% and 36% in the control and warmed plots| respectively. In 2001| warming resulted in a 105% increase in ragweed aboveground biomass (AGB)| and the ratio of ragweed AGB to total AGB increased by 79%. Dry mass per ragweed stem in the warmed plots was 37% and 38% greater than that in the control plots in 2000 and 2001| respectively. Although warming caused no difference in pollen production per stem| total pollen production increased by 84% (P < 0.05) because there were more ragweed stems. Experimental warming significantly increased pollen diameter from 21.2 μm in the control plots to 23.9 μm in the warmed plots (a 13% increase). The results from our experiment suggest that global warming could aggravate allergic hazards and thereby jeopardize public health. 5673,2002,5,4,Response of Antarctic (ODP Site 690) planktonic foraminifera to the Paleocene-Eocene thermal maximum: Faunal evidence for ocean/climate change,High-resolution study of Antarctic planktonic foraminiferal assemblages (Ocean Drilling Program Site 690| Weddell Sea) shows that these microplankton underwent a stepwise series of changes during the Paleocene-Eocene thermal maximum (PETM). Initiation of this response coincides with the onset of the carbon isotope excursion (CIE) but precedes the benthic foraminiferal mass extinction. The "top-to-bottom'' succession in the biotic response indicates that the surface ocean/atmosphere was affected before the deep sea. The earliest stage of the faunal response entailed a conspicuous turnover within the shallow-dwelling genus Acarinina and a succession of stratigraphic first appearances. The genus Morozovella| large (>180 mum) biserial planktonics| and A. wilcoxensis are all restricted to the lower CIE within this PETM section. Acarininid populations crashed as the ocean/climate system ameliorated during the CIE recovery| reflecting atypical surface water conditions. This transient decline in acarininids is paralleled by a marked increase in carbonate content of sediments. It is postulated that this interval of carbonate enrichment| and its unusual microfauna| reflects enhanced carbon storage within reservoirs of the global carbon cycle other than the marine carbonate system [sensu Broecker et al.| 1993; Ravizza et al.| 2001]. 5713,2002,4,4,Response of monsoon variability in Himalayas to global warming,Reconstructed annual net accumulation from the Dasuopu ice core recovered in Himalayas| with a good correlation to Indian monsoon| reflects a major precipitation trend in central Himalayas. The Dasuopu accumulation (DSP An) also shows a strong correlation to the Northern Hemispheric temperature. Generally| as the Northern Hemispheric temperature increases by 0.1 K| the accumulation decreases by about 90 mm and vise versa. Under the condition of global warming| especially since 1920| the Northern Hemispheric mean temperature has increased by about 0.5 K| whereas accumulation in Dasuopu ice core has decreased by about 450 mm. According to the relationship between accumulation and temperature| a scenario prediction of monsoon rainfall in central Himalayas is made. 5907,2002,2,4,Response of monsoonal temperate glaciers to global warming since the Little Ice Age,Monsoonal temperate glaciers in China mainly occur in the southeastern part of Qinghai (Tibetan) Plateau. They constitute an area of 13203.2 km(2)| accounting for 22.2% of China's total glaciated area. Such glaciers are extremely sensitive to climatic warming due to their unique characters. An inconsiderable rise in air temperature may lead to a significant rise in ELA and a large shrinkage in glacier area. Since the maximum of the Little Ice Age (17th century) the mean temperature of monsoonal temperate glaciers in China has increased by 0.8degreesC and the glacier area has decreased by 3921.2 km(2)| an amount equivalent to 30% of the modern glacier area. It is predicted that by the year 2100 the temperature in the monsoonal temperate glaciers of China will rise by 2.1degreesC| the glacier area will decrease by 75%| approximately 9900 km(2). If the precipitation decreases| the retreat of the glaciers will be even faster| but the area reduction percentage of the glaciers will not exceed 80%. This will no doubt pose a serious threat to the water resources and environment in these regions. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved. 5792,2002,2,4,Response of Picea abies populations from elevational transects in the Polish Sudety and Carpathian mountains to simulated drought stress,The response of 24 Norway spruce populations from a broad elevational gradient to four combinations of watering and temperature was studied in a phytotron experiment. The results of this experiment are important for better understanding possible impacts of global warming on low- and high-altitude populations of Picea abies. The investigated populations showed evidence of clinal variation in height| mass and bud-set parameters in all treatments. The higher the elevation of origin| the earlier the bud-set and the poorer the mass and height of the populations. The interaction of population origin x treatment showed a small percentage variance component| but there was a clear differentiation in reaction of the tested populations to the simulated drought. The low-altitude populations showed a strong negative reaction to the drought stress| whereas the high-altitude ones were more drought tolerant. So if global warming would be accompanied by soil drought| the low-altitude populations would reduce their growth much more than the high-altitude ones. But if global warming would be combined with an adequate increase of precipitation| then low-altitude populations would profit from this climate change more than high-altitude ones. (C) 2002 Elsevier Science B.V. All rights reserved. 5676,2002,2,3,Response of the antarctic circumpolar current transport to global warming in a coupled model,[1] The transient and long-term adjustment process of the Antarctic Circumpolar Current (ACC) in response to global warming in the CSIRO climate model is examined in an integration| which is run under increasing atmospheric CO2 following the IPCC/IS92a scenario to stabilisation at triple the initial CO2 concentration (3 x CO2). The ACC transport through Drake Passage shows an evident strengthening along with the CO2 increase and| in the subsequent period with stabilised 3 x CO2| it keeps increasing steadily after CO2 tripling for a few centuries until a maximum (151 Sv| 17% larger than the initial state) is reached. The strengthening of the ACC transport results from the warming-induced enhancement of the meridional density gradient in the ocean interior across the ACC: it leads to a speedup of the upper layer zonal flow which outweighs the deceleration in the underlying layer caused by the weakening of the deep overturning off Antarctica. 5876,2002,5,4,Response of tropical vegetation to Paleogene warming,The late Paleocene-early Eocene transition was characterized by along period of global warming that culminated with the highest temperatures of the Cenozoic. This interval is associated with a significant increase in plant diversity in temperate latitudes. However| data from tropical regions remain largely unknown. The record of pollen and spore diversity across the late Paleocene to the early middle Eocene of eight sections in central and eastern Colombia was analyzed. Several techniques| including range-through method| rarefaction| bootstrap| detrended correspondence analysis| and Shannon index| were used to assess the significance of the observed diversity pattern. The palynofloral record indicates that the lower to middle Eocene contains a significantly higher palynofloral diversity than the underlying upper Paleocene strata. This pattern is maintained after accounting for sample size| number of samples/time unit| lithofacies| and depositional systems. Eocene palynofloras have higher alpha and beta diversities and a higher equitability than Paleocene palynofloras. This increase in diversity is the product of a gradual increase in the rate of first appearances and a gradual decrease in the rate of last appearances. The early to middle Eocene increase in diversity| as well as the increase in spore abundance and diversity| suggests that tropical (equatorial) climate became wetter during the early to middle Eocene. This interpretation favors causes for early Eocene warming that do not involve significant increases in greenhouse gases. Samples from strata associated with the Paleocene/Eocene thermal maximum were barren for palynomorphs| and the effects of this climatic event on tropical vegetation remains uncertain. 5797,2002,4,2,Responsibility for past and future global warming: Uncertainties in attributing anthropogenic climate change,During the negotiations on the Kyoto Protocol| Brazil proposed a methodology to link the relative contribution of Annex I Parties to emission reductions with the relative contributions of Parties to the global-mean temperature increase. The proposal was not adopted during the negotiations but referred to the Subsidiary Body for Scientific and Technological Advice for consideration of its methodological aspects. In this context we analyze the impact of model uncertainties and methodological choices on the regionally attributed global-mean temperature increase. A climate assessment model has been developed to calculate changes in greenhouse gas concentrations| global-mean temperature and sea-level rise attributable to individual regions. The analysis shows the impact of the different choices in methodological aspects to be as important as the impact of model uncertainties on a region's contribution to present and future global temperature increases. Choices may be the inclusion of the anthropogenic non-CO2 greenhouse gas emissions and/or the CO2 emissions associated with land-use changes. When responsibility to global temperature change is attributed to all emitting Parties| the impacts of modeling uncertainties and methodological choices on contributions of individual Parties are considerable. However| if relative contributions are calculated only within the group of Annex I countries| the results are less sensitive to the uncertainty aspects considered here. 5678,2002,2,4,Revised 21st century temperature projections,Temperature projections for the 21st century made in the Third Assessment Report (TAR) of the United Nations Intergovernmental Panel on Climate Change (IPCC) indicate a rise of 1.4 to 5.8degreesC for 1990-2100. However| several independent lines of evidence suggest that the projections at the upper end of this range are not well supported. Since the publication of the TAR| several findings have appeared in the scientific literature that challenge many of the assumptions that generated the TAR temperature range. Incorporating new findings on the radiative forcing of black carbon (BC) aerosols| the magnitude of the climate sensitivity| and the strength of the climate/carbon cycle feedbacks into a simple upwelling diffusion/energy balance model similar to the one that was used in the TAR| we find that the range of projected warming for the 1990-2100 period is reduced to 1.1-2.8degreesC. When we adjust the TAR emissions scenarios to include an atmospheric CO2 pathway that is based upon observed CO2 increases during the past 25 yr| we find a warming range of 1.5-2.6degreesC prior to the adjustments for the new findings. Factoring in these findings along with the adjusted CO2 pathway reduces the range to 1.0-1.6degreesC. And thirdly| a simple empirical adjustment to the average of a large family of models| based upon observed changes in temperature| yields a warming range of 1.3-3.0degreesC| with a central value of 1.9degreesC. The constancy of these somewhat independent results encourages us to conclude that 21st century warming will be modest and near the low end of the IPCC TAR projections.
5746,2002,4,4,Revision of the global carbon budget due to changing air-sea oxygen fluxes,[1] Carbon budgets inferred from measurements of the atmospheric oxygen to nitrogen ratio (O-2/N-2) are revised considering sea-to-air fluxes of O-2 and N-2 in response to global warming and volcanic eruptions. Observational estimates of changes in ocean heat content are combined with a model-derived relationship between changes in atmospheric O-2/N-2 due to oceanic outgassing and heat fluxes to estimate ocean O-2 outgassing. The inferred terrestrial carbon sink for the 1990s is reduced by a factor of two compared with the most recent estimate by the Intergovernmental Panel on Climate Change (IPCC). This also improves the agreement between calculated ocean carbon uptake rates and estimates from global carbon cycle models| which indicate a higher ocean carbon uptake during the 1990s than the 1980s. The simulated decrease in oceanic O-2 concentrations is in qualitative agreement with observed trends in oceanic O-2 concentrations. 5921,2002,2,4,River-lake system in a mosaic landscape; Main results and some implications for theory and practice from studies on the river Jorka system (Masurian Lakeland| Poland),The basic results and conclusions of multi-year studies (described in detail in previous papers) on the river-lake system in the lakeland region of north-eastern Poland are shortly presented in relation to the selected general ecological problems. The study area was proved to be representative of the mosaic landscape structure and of the river-lake system as atrophic continuum with the spatial pattern of human impact established a century ago. Generally low export rates of nutrients and relatively low input to the lakes were found as typical of the region. However| year-to-year variation in nutrient export from the lake watersheds was high| mostly related to the discharge variation| and highest in the vernal period; the highest values were found for polluted fragments of the watershed. The long-term relative stability of in-lake trophic conditions was found and their basic relation to the lake position in the river system. The role of wetlands (isolated patches and the zones close to lakes) in diminishing the nutrient input was proved and their vegetation was described. Some consequences of the possible global warming and decrease in discharge and water table in the region were pointed out| such as the pulsing (concentrated in the freshet period) system of water and nutrient supplying| sink or source function of lakes in the river system (positive or negative nutrient retention in successive lakes)| change in eutrophication rate| and its symptoms. The main implications for watershed management in the lakeland region are indicated. 5831,2002,2,4,Role of environmental temperature in aging and longevity: insights from neurolipofuscin,The available evidence for thermal modulation of neurolipofuscin deposition in poikilotherms is reviewed here and additional data are contributed. Mainly decapod crustacean models are employed and neurolipofuscin is treated as an index of physiological aging. In all cases| neurolipofuscin accumulation rate is positively correlated with environmental temperature but there appears to be lowered sensitivity in the thermal mid-range| an 'optimum' temperature for neurolipofuscin accumulation and possibly age-associated variation. The geographical position of the population within the species' thermal range may determine sensitivity of the response. There is seasonal oscillation of neurolipofuscin accumulation rate| providing preliminary evidence for neurolipofuscin turnover with net loss in winter. Spatial and temporal thermal variations of similar magnitude appear to have comparable effects on neurolipofuscin accumulation rate. Such effects may be extreme| suggesting important implications for physiological aging even in homeotherms. Inter-specific comparisons indicate that species-specific neurolipofuscin accumulation rates are positively correlated with habitat temperature and inversely correlated with maximum lifespan and age at maturity. These findings help explain some well-known bioclimatic trends in maturation- and maximum body size| such as Bergmann's rule. They also highlight the fact that global warming is likely to cause significant changes in life history parameters| population dynamics and responses to exploitation for many species. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. 2926,2002,2,3,Roles of food web and heterotrophic microbial processes in upper ocean biogeochemistry: Global patterns and processes,The growth and dynamics of plankton in the ocean vary with natural cycles| global climate change and the long-term evolution of ecosystems. The ocean is a large reservoir for CO2 and the food webs in the upper ocean play critical roles in regulating the global carbon cycle| changes in atmospheric CO2 and associated global warming. Microheterotrophs are a key component of the upper ocean food webs. Here| we report on the results of an analysis of the distribution of bacteria and related properties in the World Ocean. We found that| for the data set as a whole| there is a significant latitudinal gradient in all field-measured and computed bacterial properties| except growth rate. Gradients were| for the most part| driven by an equator-ward increase in the Southern Hemisphere. The biomass| rates of production and respiration and dissolved organic carbon concentrations were significantly higher in the Northern than the Southern hemispheres. In contrast| growth rates were the same in the two hemispheres. We conclude that the lower biomass and production in the Southern Hemisphere reflects greater top-down control by microbial grazers| which would be due to a lower abundance or activity of omnivorous zooplankton in the Southern than Northern Hemispheres. These large spatial differences in dynamics| structure and activity of the bacterial community and the microbial food web will be reflected in different patterns of carbon cycling| export and air-sea exchange of CO2 and the potential ability of the ocean to sequester carbon. 5852,2002,2,4,Satellite evidence of phenological differences between urbanized and rural areas of the eastern United States deciduous broadleaf forest,We used a 10-year record (1990-99) of composited and cloud-screened reflectances from the Advanced Very High Resolution Radiometer (AVHRR) to test for phenological differences between urban and rural areas in the eastern United States deciduous broadleaf forest (DBF). We hypothesized that well-documented urban heat island effects would be associated with alterations in temperature-sensitive vegetation phenology. Our objectives were thus (a) to investigate possible differences in the start of the growing season (SOS) and end of the growing season (EOS) between the urban and DBF land covers| (b) to investigate related differences in greenness amplitude and fractional cover| and (c) to develop a generalized additive model (GAM) to predict the spatial variation of observed differences. By analyzing individual 1degrees latitude by 1degrees longitude blocks| we found that| on average| urbanization is associated with a growing season expansion of 7.6 days. Most of this effect is caused by an earlier SOS in urban areas. In all cases| urban regions had lower fractional cover and greenness amplitude. The GAM model failed to produce a viable model for differences in EOS| probably because it is dominated by photoperiod controls with only a minor temperature impact. SOS differences were predicted with an accuracy of about 2.4 days| with a GAM consisting of smoothed functions of mean annual average temperature| urban fractional cover| and the urban vs DBF greenness amplitude difference. We speculate that evidence of a phenoiogical response to warming indicates that global warming| without reduction in DBF vegetation cover and greenness amplitude| may increase carbon sequestration in mesic deciduous forests. 5677,2002,4,4,Satellite-based detection of global urban heat-island temperature influence,This study utilizes a satellite-based methodology to assess the urban heat-island influence during warm season months for over 4400 stations included in the Global Historical Climatology Network of climate stations. The methodology includes local and regional satellite retrievals of an indicator of the presence green photosynthetically active vegetation at and around the stations. The difference in local and regional samples of the normalized difference vegetation index (NDVI) is used to estimate differences in mean air temperature. Stations classified as urban averaged 0.90degreesC (N. Hemisphere) and 0.92degreesC (S. Hemisphere) warmer than the surrounding environment on the basis of the NDVI-derived temperature estimates. Additionally| stations classified as rural averaged 0.19degreesC (N. Hemisphere) and 0.16degreesC (S. Hemisphere) warmer than the surrounding environment. The NDVI-derived temperature estimates were found to be in reasonable agreement with temperature differences observed between climate stations. The results suggest that satellite-derived data sets can be used to estimate the urban heat-island temperature influence on a global basis and that a more detailed analysis of rural stations and their surrounding environment may be necessary to assure that temperature trends derived from assumed rural environments are not influenced by changes in land use/land cover. 2873,2002,3,3,Screening| evaluation| and ranking of oil reservoirs suitable for CO2-flood EOR and carbon dioxide sequestration,Geological sequestration of CO2 in EOR operations has been recognized as one of the more viable means of reducing emissions of anthropogenic CO2 into the atmosphere in response to global climate change. This option| which lowers the cost of CO2 sequestration by recovering incremental oil| is particularly attractive in mature sedimentary basins| such as the Western Canada Sedimentary Basin where many oil pools are near depletion| and where most of the needed infrastructure is already in place. A method was developed for the rapid screening and ranking of oil reservoirs suited for CO2-flood EOR| which is particularly fit for a very large number of reservoirs as listed in reserves databases| and which does not require detailed reservoir engineering analysis. Oil reservoirs are screened on the basis of oil gravity| reservoir temperature and pressure| minimum miscibility pressure and remaining oil saturation| to determine their suitability for CO2 flooding| and an analytical method is used to calculate the incremental oil recovery at breakthrough and for any hydrocarbon pore volume (HCPV) fraction of injected CO2. In addition| the reservoir capacity for CO2 sequestration is calculated. Reservoirs are ranked according to a set of criteria with corresponding assigned weights to identify and select the best suited reservoir for CO2 flooding and sequestration. The method was applied to 8|637 oil reservoirs listed in the 2000 Alberta reserved database. Of these| 4|470 passed the screening criteria and were ranked based on technical and performance characteristics. Preliminary calculations predict that 150 X 10(6)| 422 X 10(6)| or 558 X 10(6) m(3)| of additional oil could be produced from Alberta's reservoirs at breakthrough| and a 50% and 100% HCPV of injected CO2| respectively; meanwhile sequestering 127| 591 and 1|118 Mt CO2| respectively. Thus| geological sequestration of CO2| in Alberta oil reservoirs suitable for CO2 flooding could provide a means for a significantly reducing anthropogenic CO2 emissions from major point sources while| at the same time| realizing an economic benefit. 5879,2002,2,4,Seasonal fluctuations in sand temperature: effects on the incubation period and mortality of loggerhead sea turtle (Caretta caretta) pre-emergent hatchlings in Minabe| Japan,Incubation period.| hatching success| and emergence percentage in loggerhead (Caretta caretta) nests were quantified during the 1993 and 1995 nesting seasons and following incubation seasons in Minabe| Wakayama| Japan. Sand and nest temperatures were also monitored. Over the seasons| daily mean sand temperature at nest depth fluctuated between 18.0degreesC and 33.3degreesC| with a steep increase in the second week of July and a peak in late August. Temperatures inside the nest chambers were a few degrees above those of the surrounding sand at the end of incubation. The incubation period ranged from 46 to 82 days. A significant negative correlation was found between mean sand temperature and incubation period. The relationship conformed to the day-degree concept. There was no significant seasonal trend in hatching success| but many pre-emergent hatchlings were found dead in most of the clutches during the warmest part of the season. Emergence percentage was correlated with mean sand temperature calculated for 4 days before emergence| suggesting that mortality may be due to heat. This heat-related mortality is considered to be a common phenomenon at our study site| because the peak in emergences coincides with the peak in high temperatures. These temperature effects on hatchling mortality must be taken into account in estimates of hatchling sex ratios. Because sand temperatures already exceed the optimal thermal range for incubation| this population is vulnerable to even small temperature increases resulting from global warming. 5692,2002,2,4,Seasonal variation in condition| growth and food habits of walleye in a Great Plains reservoir and simulated effects of an altered thermal regime,Catch rates in gillnets and relative weight (W-r) of walleye Stizostedion vitreum| in Glen Elder Reservoir| Kansas| were lowest during the summer (June-August) and highest during the autumn (September-November). Approximately 80% of their annual growth in length and mass was attained during late summer and autumn. Growth was minimal during winter (January-February) and spring (March-May). The number of walleye with empty stomachs was highest during the summer. Invertebrates (Cladocera| Chironomidae) were common in walleye stomachs during the summer and spring| but contributed little to the ingested biomass. Gizzard shad Dorosoma cepedianum dominated walleye diets (per cent by mass) throughout the year. A bioenergetics model predicted that the proportion of maximum consumption (P-c) was highest during the autumn and was probably due to spatial overlap of walleye and gizzard shad once water temperatures were <22degreesC. The bioenergetics model predicted that walleye would lose up to 65% of their body mass during the summer if water temperature increased by 10% (as predicted by some global warming models). Growth during the autumn| winter and spring was enhanced up to 150% by increased temperatures. The results of this study indicate that lower condition| reduced consumption and slow growth are a generalized| response of walleye to extreme temperatures. Elevated temperatures may have a net positive effect on walleye growth if they can survive the high thermal stress during summer. (C) 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. 2881,2002,3,3,Sediment carbon concentration and transport from small watersheds under various conservation tillage practices,Carbon sequestration by soils is viewed as a process that can reduce CO2 emission and its potential impacts on global climate change. Therefore| impacts of various agricultural management practices on carbon (C) release/sequestration need to be assessed. The objective of this study was to measure C concentrations and transport in sediments lost with various tillage practices on small watersheds. Corn-soybean/rye (Zea mays L. Glycine max (L.) Merr./Secale cereale L.) rotations with no-till| chisel-plow| and paraplow were studied on small watersheds (0.55-0.79 ha). Disk tillage preceding the corn and soybean crops of a corn-soybean-wheat (Triticum aestivum L.)/clover (Trifolium pratense L.) rotation was also studied. Each small watershed was instrumented with a 60 cm H-flume mounted on a concrete approach| and a Coshocton wheel for collecting a proportional sample of water and sediment. Samples of sediment deposited in the flume approach and in runoff were collected during a 15-year period and analyzed for total C concentration. Weighted averages of C in the sediment that passed through the flumes during the treatment periods did not differ significantly among tillage treatments| although no-till had the highest C (30 g kg(-1)) and disk had the lowest C (23 g kg(-1)) in the last 9 years of the study period. Weighted averages of C concentration in the flume floor sediments were slightly lower (21-23 g kg(-1)). For comparison| weighted C concentration in sediment that passed through flumes from small fertilized| pastured watersheds ranged from 52 to 72 g kg(-1). Average annual sediment loss was 532| 828| and 1152 kg ha(-1) for no-till| chisel-plow| and disk| respectively. Annual average transport of C via sediment was 13.8| 15.0| 12.7| and 24.0 kg ha(-1) for no-till| chisel-plow| paraplow| and disk| respectively. Although tillage practices may reduce C transport in sediment by lowering concentrations| a greater factor for reducing C movement is reducing sediment movement. This information will be useful to policy makers and others who need to put definitive values on land management practices in terms of C sequestration/release. Published by Elsevier Science B.V. 2929,2002,2,4,Sensitivity of stomatal and canopy conductance to elevated CO2 concentration - interacting variables and perspectives of scale,The hydrological response of forests to rising CO2 is a critical biotic feedback in the study of global climate change. Few studies| however| have investigated this highly dynamic response at relevant temporal and spatial scales. A combination of leaf and whole-tree measurements and stand-level extrapolations were used to assess how stomatal conductance| canopy transpiration and conductance| and evapotranspiration might be affected by future| higher CO2 concentrations. Midday measurements of stomatal conductance for leaves sampled in a 12-yr-old sweetgum (Liquidambar styraciflua) stand exposed to free-air CO2 enrichment were up to 44% lower at elevated than at ambient CO2 concentrations| whereas canopy conductance| averaged over the growing season| was only 14% lower in stands exposed to CO2 enrichment. The magnitude of this response was dependent on vapor pressure deficit and soil water potential. Annual estimates of evapotranspiration showed relatively small reductions due to atmospheric CO2 enrichment. These data illustrate that the hydrological response of a closed-canopy plantation to elevated CO2 depends on the temporal and spatial scale of observation. They emphasize the importance of interacting variables and confirm that integration of measurements over space and time reduce what| at the leaf level| might otherwise appear to be a large and significant response. 5724,2002,2,3,Sensitivity of the hydrological cycle to increasing amounts of greenhouse gases and aerosols,The coupled atmosphere-ocean Climate Model of the Centre National de Recherches Meteorologiques (CNRM) has been used to run a time-dependent climate change experiment to study the impact of increasing amounts of greenhouse gases and aerosols on the simulated water cycle. This simulation has been initialised with the oceanic temperature and salinity profiles and the atmospheric trace gas concentrations observed in the 1950s| and has been carried out for 150 years after a 20-year spin-up. The simulated climate change has been analysed as the difference between two 30-year time slices: 1970-2000 and 2070-2100 respectively. The model achieves a reasonable simulation of present-day climate and simulates a general increase in precipitation throughout the twenty first century. The main exceptions are the subtropics| where the enhanced Hadley circulation has a drying impact| and the midlatitude continents| where the increased evaporation in spring and decreased moisture convergence in summer lead to a relative summer drying. Global and regional analyses suggest that the precipitation increase is generally limited by a decrease in the water vapour cycling rate and in the precipitation efficiency| which appear as key parameters of the simulated water cycle. In order to reduce the spread between climate scenarios| more efforts should be devoted to estimate these parameters from satellite observations and meteorological analyses| and their possible evolution over recent decades. In the present study| the impacts of global warming on the surface hydrology have been also investigated. The main findings are the amplification of the annual cycle of soil moisture in the mid-and-high latitudes| and the decrease in the Northern Hemisphere snow cover| at a rate that is consistent with recent satellite estimations and should increase during the twenty first century. The runoff simulated over the 1950-2100 period has been converted into river flow using a linear river routeing model. The trends simulated over recent decades are surprisingly consistent with the river flow measurements available from the Global Runoff Data Centre. These trends can differ from those estimated over the whole 150-year integration| thereby indicating that it is not safe to predict hydrological impacts just by extrapolating the trends found in the available observations. Our climate model seems likely to provide qualitative hydrological scenarios over large river basins| but it still shows serious biases in the simulation of present-day river flows. Regional hydrological projections remain a challenge for the global climate modelling community and downscaling techniques are still necessary for this purpose. 2897,2002,4,4,Separating methane production and consumption with a field-based isotope pool dilution technique,[1] Despite the importance of methane for climate| it has remained difficult to measure gross rates of methane production and consumption without inducing artifacts. To remedy this| we have developed| tested| and applied a field-based (CH4)-C-13 pool dilution technique. Laboratory tests| sensitivity analyses| and field data indicate that this technique is robust for measuring gross rates of methane production and consumption. In our analyses of 130 soil cores from 17 field sites of differing environmental conditions| we encountered a wide range of gross methane production rates (0.04-930 mg CH4-C m(-2) day(-1))| but encountered a narrower range of consumption rates (0.1-9.2 mg CH4-C m(-2) day(-1)). Unexpectedly| we found that gross production of methane was common (mean = 0.15 mg CH4-C m(-2) day(-1)) even in dry| oxic soils where average soil conditions cannot support methane producers. Through improved measurement of methane turnover in soils| this technique can offer a more fine-grained understanding of how productive and consumptive processes are linked to soil-atmosphere trace gas balances. 5948,2002,3,3,Shade trees reduce building energy use and CO2 emissions from power plants,Urban shade trees offer significant benefits in reducing building air-conditioning demand and improving urban air quality by reducing smog. The savings associated with these benefits vary by climate region and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree-planting programs can be designed to have lower costs so that they offer potential savings to communities that plant trees. Our calculations suggest that urban trees play a major role in sequestering CO| and thereby delay global warming. We estimate that a tree planted in Los Angeles avoids the combustion of 18 kg of carbon annually| even though it sequesters only 4.5-11 kg (as it would if growing in a forest). In this sense| one shade tree in Los Angeles is equivalent to three to five forest trees. In a recent analysis for Baton Rouge| Sacramento| and Salt Lake City| we estimated that planting an average of four shade trees per house (each with a top view cross section of 50 m(2)) would lead to an annual reduction in carbon emissions from power plants of 16|000| 41|000| and 9000 t| respectively (the per-tree reduction in carbon emissions is about 10-11 kg per year). These reductions only account for the direct reduction in the net cooling- and heating-energy use of buildings. Once the impact of the community cooling is included| these savings are increased by at least 25%. (C) 2001 Published by Elsevier Science Ltd. All rights reserved. 5711,2002,2,4,Shallow seismic surveying of an Alpine rock glacier,To map the internal structure and lower boundary of an alpine rock glacier| we recorded three shallow seismic profiles and drilled four similar to70-m-deep holes through to the underlying bedrock. Although analysis of the seismic data using standard reflection processing schemes did not yield conclusive results because of the dominantly low-frequency returned signals and the presence of strong source-generated noise| tomographic inversions of first-arrival times were successful in mapping several critical subsurface features. A thin| low-velocity layer of loose boulders| air voids| and snow was found to extend across the entire surveyed area. Below this layer| two distinct velocity regimes superimposed on a general increase in velocity with depth were identified. A broad regime of high velocities was interpreted to contain boulders with numerous ice-filled voids| whereas an adjacent regime of relatively low velocities was explained in terms of boulders with air- and water-filled voids. Ibis latter region of degraded permafrost| which was unexpected| may be an early result of global warming. The transition from rock glacier to gneissic bedrock was delineated approximately by the 4300-m/s isovelocity line. Although poorly resolved| its depth varied from similar to35 to similar to70 m beneath the surface of the rock glacier. The tomographic inversion results also provided an explanation for the occurrence of strong source-generated noise in our data. Using the derived velocity distributions as input| synthetic shot gathers were calculated using a finite-difference viscoelastic scheme that accounted for surface topography. The resultant synthetic data were dominated by the overwhelming effects of back- and side-scattered waves from shallow heterogeneities and high-amplitude guided phases that originated from the thin| surficial low-velocity zone. Had the guided phases not been correctly identified and eliminated during processing| they would have appeared as reflections in the stacked sections. Since low-velocity layers overlying heterogeneous media are common features of the shallow subsurface| our findings may have implications for a broad range of engineering-scale seismic investigations (e.g.| studies of landfills| rockslides| moraines| talus slopes| alluvial fans). 2872,2002,2,4,Signatures of large-scale and local climates on the demography of white-tailed ptarmigan in Rocky Mountain National Park| Colorado| USA,Global climate change may impact wildlife populations by affecting local weather patterns| which| in turn| can impact a variety of ecological processes. However| it is not clear that local variations in ecological processes can be explained by large-scale patterns of climate. The North Atlantic oscillation (NAO) is a large-scale climate phenomenon that has been shown to influence the population dynamics of some animals. Although effects of the NAO on vertebrate population dynamics have been studied| it remains uncertain whether it broadly predicts the impact of weather on species. We examined the ability of local weather data and the NAO to explain the annual variation in population. dynamics of white-tailed ptarmigan (Lagopus leucurus) in Rocky Mountain National Park| USA. We performed canonical correlation analysis on the demographic subspace of ptarmigan and local-climate subspace defined by the empirical orthogonal function (EOF) using data from 1975 to 1999. We found that two subspaces were significantly correlated on the first canonical variable. The Pearson correlation coefficient of the first EOF values of the demographic and local-climate subspaces was significant. The population density and the first EOF of local-climate subspace influenced the ptarmigan population with 1-year lags in the Gompertz model. However| the NAO index was neither related to the first two EOF of local-climate subspace nor to the first EOF of the demographic subspace of ptarmigan. Moreover| the NAO index was not a significant term in the Gompertz model for the ptarmigan population. Therefore| local climate had stronger signature on the demography of ptarmigan than did a large-scale index| i.e.| the NAO index. We conclude that local responses of wildlife populations to changing climate may not be adequately explained by models that project large-scale climatic patterns. 5726,2002,3,3,Silicon oxide contact hole etching employing an environmentally benign process,An environmentally benign etching process using a solid material evaporation technique has been investigated for preventing global warming. In this process| a polytetrafluoroethylene is evaporated by a CO2 laser| resulting in production of fluorocarbon species working as the etching species. Therefore| this system employs no perfluorocompound feed gases| which cause global warming| and enables us to design a new plasma chemistry using the solid material. The system was successfully applied to a SiO2 contact hole etching process employing a planar electron cyclotron resonance plasma. The etched profile was successfully controlled by varying the Ar dilution ratio and the process pressure. In a 0.6 mum contact hole and a 0.08 mum trench fabrication process| this novel process enables us to realize high etching performances| where the etching rate Of SiO2| selectivities of SiO2/resist| and SiO2/Si were 340 nm/min| 6.8 and 31| respectively| in optimal condition. To clarify the plasma chemistry using solid material evaporation| CFx (x = 1-3) radical densities and F atom density were measured by infrared diode laser absorption spectroscopy and actinometric optical emission spectroscopy| and fluorocarbon films deposited on SiO2 were analyzed by x-ray. photoelectron spectroscopy. On the basis of these results| the etching mechanism was discussed. (C) 2002 American Vacuum Society. 5708,2002,2,3,Simulating the impacts of climate change on cotton production in the Mississippi Delta,General circulation models (GCMs) project increases of the earth's surface air temperatures and other climate changes in the middle or latter part of the 21st century| and therefore crops such as cotton (Gossypium hirsutum L.) will be grown in a much different environment than today. To understand the implications of climate change on cotton production in the Mississippi Delta| 30 years (1964 to 1993) of cotton growth and yield at Stoneville| Mississippi| USA| were simulated using the cotton simulation model GOSSYM. The GCM projections showed a nearly 4degreesC rise in average temperature and a decrease in precipitation during the crop growing season. The fertilization effect of an increase in atmospheric CO2 concentrations from 360 to 540 ppm| without the change in other climatic variables| increased yields by 10% from 1563 to 1713 kg ha(-1)| but when all projected climatic changes were included| yields decreased by 9% from 1563 to 1429 kg ha(-1). The rate of plant growth and development was higher in the future because of enhanced metabolic rates at higher temperatures combined with increased carbon availability. The effect of climate change on cotton production was more drastic in a hot and dry year. Since most of the days with average temperatures above 32degreesC will likely occur during the reproductive phase| irrigation will be needed to satisfy the high water demand| and this reduces boll abscission by lowering canopy temperatures. Therefore| if global warming occurs as projected| fiber production in the future environment will be reduced| and breeding heat-cold-tolerant cultivars will be necessary to sustain cotton production in the US mid-South. Cultural practices such as earlier planting may be used to avoid the flowering of cotton in the high temperatures that occur during mid to late summer. 5766,2002,2,3,Simulation of hydrologic changes associated with global warming,[1] Using the results obtained from a coupled ocean-atmosphere-land model with medium computational resolution| we investigated how the hydrology of the continents changes in response to the combined increases of greenhouse gases and sulfate aerosols in the atmosphere| which are determined based upon the IS92a scenario. In order to extract the forced response from natural| internal variability| the difference between the mean of an eight-member ensemble of numerical experiments and a control experiment are used for the present analysis. The global mean surface air temperature of the coupled model increases by about 2.3 degreesC above the preindustrial level by the middle of the 21st century. Accompanying the warming| the global mean rates of both precipitation and evaporation increase by 5.2%| yielding the average increase in the rate of runoff by approximately 7.3%. The increase in the rate of runoff simulated by the model is particularly large in high northern latitudes| where the runoff from some rivers such as the Mackenzie and Ob may increase by as much as 20%. Runoff from many European rivers increases by more than 20%. Runoff also increases substantially in some tropical rivers such as the Amazon and Ganges. However| the percentage changes in simulated runoff from many other tropical rivers and middle latitude rivers are smaller with both positive and negative signs. In middle and high latitudes in the Northern Hemisphere| soil moisture tends to decrease in summer| whereas it increases in winter. However| in many semi-arid regions in subtropical and middle latitudes| soil moisture is reduced during most of a year. These semi-arid regions include the southwestern part of North America| the northeastern part of China in the Northern Hemisphere| and the region in the vicinity of the Kalahari Desert and southern part of Australia in the Southern Hemisphere. Since a semi-arid region usually surrounds a desert| the reduction of soil moisture in such a region often results in the expansion of the desert. Soil moisture is also reduced during the dry season in many semi-arid regions. For example| it is reduced in the savannahs of Africa and South America during winter and early spring in the Southern Hemisphere. In the Northern Hemisphere| it is reduced at the Mediterranean coast of Europe in summer. 5690,2002,2,3,Site and temporal variation of soil respiration in European beech| Norway spruce| and Scots pine forests,Global warming and changes in rainfall amount and distribution may affect soil respiration as a major carbon flux between the biosphere and the atmosphere. The objectives of this study were to investigate the site to site and interannual variation in soil respiration of six temperate forest sites. Soil respiration was measured using closed chambers over 2 years under mature beech| spruce and pine stands at both Solling and Unterluss| Germany| which have distinct climates and soils. Cumulative annual CO2 fluxes varied from 4.9 to 5.4 Mg C ha(-1) yr(-1) at Solling with silty soils and from 4.0 to 5.9 Mg C ha(-1) yr(-1) at Unterluss with sandy soils. With one exception soil respiration rates were not significantly different among the six forest sites (site to site variation) and between the years within the same forest site (interannual variation). Only the respiration rate in the spruce stand at Unterluss was significant lower than the beech stand at Unterluss in both years. Soil respiration rates of the sandy sites at Unterluss| were limited by soil moisture during the rather dry and warm summer 1999 while soil respiration at the silty Solling site tended to increase. We found a threshold of -80 kPa at 10 cm depth below which soil respiration decreased with increasing drought. Subsequent wetting of sandy soils revealed high CO2 effluxes in the stands at Unterluss. However| dry periods were infrequent| and our results suggest that temporal variation in soil moisture generally had little effect on annual soil respiration rates. Soil temperature at 5 cm and 10 cm depth explained 83% of the temporal variation in soil respiration using the Arrhenius function. The correlations were weaker using temperature at 0 cm (r(2) = 0.63) and 2.5 cm depth (r(2) = 0.81). Mean Q(10) values for the range from 5 to 15 degreesC increased asymptotically with soil depth from 1.87 at 0 cm to 3.46 at 10 cm depth| indicating a large uncertainty in the prediction of the temperature dependency of soil respiration. Comparing the fitted Arrhenius curves for same tree species from Solling and Unterluss| revealed higher soil respiration rates for the stands at Solling than in the respective stands at Unterluss| at the same temperature. A significant positive correlation across all sites between predicted soil respiration rates at 10 degreesC and total phosphorus content and C-to-N ratio of the upper mineral soil indicate a possible effect of nutrients on soil respiration. 2949,2002,4,4,Social and ecological responses to climate change: towards an integrative understanding,A literature review and a survey of professionals whose work deals with climate change indicate that more is known and considered certain by the natural science community concerning responses of natural systems to climate change. There is less of a consensus among social scientists that social systems are directly responding to climate change. The emphasis in the literature on policy and mitigation is corroborated by the survey results| which revealed only social variables that are tightly linked to climate or natural systems. Identifying variables of both natural and social systems that respond to climate change is imperative for a better understanding of the implications of climate change. 5729,2002,3,4,Soil carbon sequestration in China through agricultural intensification| and restoration of degraded and desertified ecosystems,The industrial emission of carbon (C) in China in 2000 was about I Pg yr(-1)| which may surpass that of the United States (1.84 Pg C) by 2020. China's large land area| similar in size to that of the United States| comprises 124 Mha of cropland| 400 Mha of grazing land and 134 Mha of forestland. Terrestrial C pool of China comprises about 35-60 Pg in the forest and 120-186 Pg in soils. Soil degradation is a major issue affecting 145 Mha by different degradative processes| of which 126 Mha are prone to accelerated soil erosion. Total annual loss by erosion is estimated at 5.5 Pg of soil and 15.9 Tg of soil organic carbon (SOC). Erosion-induced emission of C into the atmosphere may be 32-64 Tg yr(-1). The SOC pool progressively declined from the 1930s to 1980s in soils of northern China and slightly increased in those of southern China because of change in land use. Management practices that lead to depletion of the SOC stock are cultivation of upland soils| negative nutrient balance in cropland. residue removal. and soil degradation by accelerated soil erosion and salinization and the like. Agricultural practices that enhance the SOC stock include conversion of upland to rice paddies| integrated nutrient management based on liberal use of biosolids and compost| crop rotations that return large quantities of biomass. and conservation-effective systems. Adoption of recommended management practices can increase SOC concentration in puddled soil. red soil| loess soils| and salt-affected soils. In addition| I soil restoration has a potential to sequester SOC. Total potential of soil C sequestration in China is 105-198 Tg C yr(-1) of SOC and 7-138 Tg C yr(-1) for soil inorganic carbon (SIC). The accumulative potential of soil C sequestration of I I Pg at an average rate of 224 Tg yr(-1) may be realized by 2050. Soil C sequestration potential can offset about 20 per cent of the annual industrial emissions in China. Copyright (C) 2002 John Wiley Sons| Ltd. 2907,2002,2,3,Soil organic carbon pool of grassland soils on the Qinghai-Tibetan Plateau and its global implication,A study of carbon (C) storage in the 0-0.75-m profile Of Soils subtending various types of grasslands on the Qinghai-Tibetan Plateau showed that the organic carbon content of the 1 627 000 km(2) of such lands in the region reaches 33.52 Pg of C. Organic carbon is mainly stored in the meadow and steppe soils of the Plateau| which combined| represents 23.2 Pg of C stored in organic form. This represents 23.44% of China's total organic soil-stored carbon and 2.5% of the global pool of soil carbon as of 1996. Carbon emissions from the grassland soils were estimated based on the two major modes of emission: (i) natural soil respiration and (ii) shifts in net C flux to/from soil due to land-use changes and their potential influence on organic matter decomposition. Annual soil respiration-driven CO2 emissions from the grassland soils of the plateau reached 1.17 P g C year(-1)| accounting for 26.4% of China's total soil respiration and 1.73% of global soil respiration. Because the grassland area accounts for 1.02% of the global terrestrial land and 16.9% of China's total terrestrial land| this CO2 emission rate is significantly higher than the country's mean annual rate (approx. 4.2 Pa C year(-1)) and even higher than the global mean rate (approx. 68 Pg C year(-1)). In the last 30 years| approximately 3.02 Pg C have been emitted from the grassland soils of the plateau due to land-use changes and grassland degradation. The total CO2 emissions rate from the grassland soils of the plateau reached 1.27 Pg C year(-1). Protecting grasslands on the Qinghai-Tibetan Plateau is of great importance in limiting global climate change. (C) 2002 Elsevier Science B.V. All rights reserved. 5723,2002,3,4,Soil organic matter| biota and aggregation in temperate and tropical soils - Effects of no-tillage,The long-term stabilization of soil organic matter (SOM) in tropical and temperate regions is mediated by soil biota (e. g. fungi| bacteria| roots and earthworms)| soil structure (e. g. aggregation) and their interactions. On average| soil C turnover was twice as fast in tropical compared with temperate regions| but no major differences were observed in SOM quality between the two regions. Probably due to the soil mineralogy dominated by 1: 1 clay minerals and oxides in tropical regions| we found a higher aggregate stability| but a lower correlation between C contents and aggregate stability in tropical soils. In addition| a smaller amount of C associated with clay and silt particles was observed in tropical versus temperate soils. In both tropical and temperate soils| a general increase in C levels (approximate to 325 +/- 113 kg C.ha(-1).yr(-1)) was observed under no-tillage compared with conventional tillage. On average| in temperate soils under no-tillage| compared with conventional tillage| CH(4) uptake (approximate to0.42 +/- 0.10 kg C-CH(4).ha(-1) yr(-1)) increased and N(2)O emissions increased (approximate to 1.95 +/- 0.45 kg N-N(2)O.ha(-1).yr(-1)). These increased N(2)O emissions lead to a negative global warming potential when expressed on a CO(2) equivalent basis. 2941,2002,4,4,Solar irradiance variability and climate,Since November 1978 a complete set of total solar irradiance (TSI) measurements from space is available| yielding a time series of more than 23 years. From measurements made by different space-based radiometers (HF on NIMBUS 7| ACRIM I on SMM| ACRIM II on UARS and VIRGO on SOHO) a composite record of TSI is compiled with an overall precision of order 0.05 Wm(-2) and a secular trend uncertainty of +/-3 ppm/year. This time series is compared with an empirical model of irradiance variability based on sunspot darkening and brightening due to faculae and network. From this comparison the model is calibrated and used to estimate possible changes of TSI in the past| using historical proxies of solar activity. For this purpose| stellar observations provide information about the possible range of solar variability over the last millennium when changes of Earth's climate are well documented. Together| the paleo solar and climate data enable a discussion of the extent of global climate change that can be explained by a variable Sun. 5910,2002,3,4,Solar-powered systems for cooling| dehumidification and air-conditioning,This paper describes current trends in solar-powered air conditioning| which has seen renewed interest in recent years due to the growing awareness of global warming and other environmental problems. Closed-cycle heat-powered cooling devices are based mainly on absorption chillers| a proven technology employing LiBr-water as the working fluid pair. Recent developments in gas-fired systems of this type make available double- and triple-effect chillers with considerably higher COP than their single-effect counterparts| which makes it possible to reduce the amount of solar heat required per kW of cooling. These systems require| however| high-temperature solar collectors. The principles of multi-staging absorption systems are described. An economic comparison is provided which shows the total system cost to be dominated by the solar part of the system. At current prices| the high COP| high temperature alternative is still more costly than the low temperature one. Open-cycle desiccant systems employing either solid or liquid sorbents are described. While the main thrust in research on novel closed-cycle absorption systems has been toward increasing the operating temperature in order to improve efficiency through multi-staging| open-cycle absorption and desiccant systems have been developed for use with low temperature heat sources such as flat plate solar collectors. A novel open-cycle (DER) system is described| which makes it possible to use the solar heat at relatively low temperatures| for producing both chilled water and cold| dehumidified air in variable quantities| as required by the load. (C) 2002 Elsevier Science Ltd. All rights reserved. 2855,2002,2,4,Some like it hot: Effects of forest clearing on nest temperatures of montane reptiles,Global climate change may affect the upper elevational limits of distribution of montane organisms| especially if those limits are set directly by temperature. Oviparous (egg-laying) reptiles are constrained in this way because of their nesting requirements. In many areas| deforestation has already subjected these animals to small-scale "climate change." Clearing for power lines (hydrocuts) increases solar radiation to potential nest sites| and hence enables these animals to penetrate higher into montane areas than would otherwise be possible. Such small-scale anthropogenic "warming" may offer a useful model system to explore consequences of broader climate change on the distribution and biology of montane organisms. We quantified thermal effects of a hydrocut in montane eucalypt forest in the Brindabella Range of southeastern Australia. The reduced canopy cover| increased duration of sunlight exposure| and higher levels of incident radiation in cleared areas substantially modified thermal regimes in potential nest sites. Orientation and exposure were the most important determinants of nest temperature and predicted the distribution of natural nests. Such cleared corridors (for roads| power lines| ski runs| etc.) may not only extend the upper elevational limit for oviparous reptiles| but may also modify the genetic structure and demography of populations. 5904,2002,2,4,Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest| Puerto Rico,We developed a spatially-explicit version of the CENTURY soil model to characterize the storage and flux of soil organic carbon (SOC| 0-30 cm depth) in the Luquillo Experimental Forest (LEF)| Puerto Rico as a function of climate| vegetation| and soils. The model was driven by monthly estimates of average air temperature| precipitation| and potential evapotranspiration (PET)| which in turn were simulated as a function of elevation| slope| and aspect using a spatially-explicit and validated model (TOPOCLIM) of solar insolation/microclimate in mountainous areas. We simulated forest gross primary productivity (GPP) and distribution of above- and below-ground biomass production using a forest productivity model (TOPOPROD). Output from TOPOCLIM and TOPOPROD models was used to run the CENTURY soil model for 1200 months under current climate conditions and in response to potential global warming. We validated our version of CENTURY soil model using 69 soil samples taken throughout the LEF. Simulated SOC storage agrees reasonably well with the observed storage (R-2 = 0.71). The simulated SOC storage in the top 30 cm within the LEF is highly variable| ranging from approximately 20-230 Mg/ha. The rates of decomposition were especially sensitive to changes in elevation. Carbon release rates due to decomposition were close to carbon assimilation rates and ranged from 0.6-0.96 Mg/ha per year at high elevations to 1.2-1.68 Mg/ha per year at lower elevations. Our simulations indicated that differences in elevation affect decomposition and SOC content primarily by changing microclimate. Finally| we found that a projected warming of 2.0 degreesC is likely to result in losses of SOC in the lower and higher elevation| but increased storage in the middle elevations in the LEF. (C) 2002 Elsevier Science B.V. All rights reserved. 2857,2002,4,2,Spatial and temporal variability in methane emissions from rice paddies: Implications for assessing regional methane budgets,Growing concern over anthropogenic global climate change has intensified the need to develop accurate budgets of atmospheric methane and other greenhouse gases. Globally| flooded rice cultivation represents a major source of atmospheric methane that is expected to grow with human population. However| current estimates of global methane flux from rice paddies vary by roughly 50%. Understanding the sources of this large variability is critical for developing management strategies for atmospheric methane. Using data collected each growing season from Texas| USA| rice paddies over a 9-year period we examined the spatial and temporal sources of methane flux variability. Using standard deviation of the mean methane flux as a measured of variability| we found that accounting for rice plant height and grain yield reduced spatial variability from 25.2 to 17.7% of the mean. Temporal variability over the entire 9-year data set was 49% of the mean| 71% of which was explained by variations in average rice plant height and total nitrogen fertilizer application. The magnitude of temporal and spatial variability suggests that reliance on single-field studies for determination of global methane budgets may be questionable. 2938,2002,2,4,Spatial Modeling of risk in natural resource management,Making decisions in natural resource management involves an understanding of the risk and uncertainty of the outcomes| such as crop failure or cattle starvation| and of the normal spread of the expected production. Hedging against poor outcomes often means lack of investment and slow adoption of new methods. At the household level| production instability can have serious effects on income and food security. At the national level| it can have social and economic impacts that may affect all sectors of society. Crop models such as CERES-Maize are excellent tools for assessing weather-related production variability. WATBAL is a water balance model that can provide robust estimates of the potential growing days for a pasture. These models require large quantities of daily weather data that are rarely available. MarkSim is an application for generating synthetic daily weather files by estimating the third-order Markov model parameters from interpolated climate surfaces. The models can then be run for each distinct point on the map. This paper examines the growth of maize and pasture in dryland agriculture in southern Africa. Weather simulators produce independent estimates for each point on the map; however| we know that a spatial coherence of weather exists. We investigated a method of incorporating spatial coherence into MarkSim and show that it increases the variance of production. This means that all of the farmers in a coherent area share poor yields| with important consequences for food security| markets| transport| and shared grazing lands. The long-term aspects of risk are associated with global climate change. We used the results of a Global Circulation Model to extrapolate to the year 2055. We found that low maize yields would become more likely in the marginal areas| whereas they may actually increase in some areas. The same trend was found with pasture growth. We outline areas where further work is required before these tools and methods can address natural resource management problems in a comprehensive manner at local community and policy levels. 5916,2002,2,4,Status of marine birds of the southeastern Beaufort Sea,This summary and update of information on the marine birds of the southeastern Beaufort Sea is intended to support discussions on how to improve management of marine resources in the Canadian Beaufort Sea region. Perhaps the most outstanding use of the Beaufort Sea by marine birds is the staging during spring migration by hundreds of thousands of eiders and long-tailed ducks in the earl open water off Cape Bathurst and Banks Island. During midsummer| tens of thousands of long-tailed ducks| scoters| scaup| and mergansers moult in the sheltered bays and behind barrier beaches and spits. Although several species of geese| ducks| loons| gulls| and terns nest on islands and in wetlands along the Beaufort Sea coast| this region has relatively few nesting seabirds compared to eastern Arctic Canada and the Bering Sea. Two possible reasons for this are a shortage of cliffs suitable for nesting and a lack of pelagic fish. The five most common sea duck species that occur in the region| long-tailed duck| king eider| common eider| surf scoter| and white-winged scoter| have all declined in numbers since the mid-1970s. Western Arctic brant populations have also declined| although their status within the Beaufort Sea region is unclear. Brant and king eider are the only marine bird species harvested there in substantial numbers. Other threats to Beaufort Sea marine bird populations include oil spills| global warming| coastal development| and contaminants. Certain threats can be managed at a. local level since they are a result of local economic development| but others| such as global warming or loss of critical wintering areas| stem from environmental problems outside the region. Solving these issues will require mutual understanding and commitment on the part of numerous countries. 2896,2002,2,4,Stocks and flows of coarse woody debris across a tropical rain forest nutrient and topography gradient,Large pieces of standing or fallen dead wood| known as coarse woody debris (CWD)| play important roles in temperate forest carbon and nutrient cycles| and affect the abundance and distribution of many classes of organisms. CWD biomass and inputs are poorly documented in tropical rain forests (TRF)| and the causes for their variation at landscape-scales in this biome have not been studied. We quantified standing and fallen CWD stocks and inputs in upland (non-swamp) old-growth TRF at the La Selva Biological Station| Costa Rica. We used a network of 18 0.5 ha plots sited in three edaphic conditions to analyze soil nutrient effects on CWD stocks and inputs controlling for topography| and to examine topographic effects controlling for soil nutrients. The edaphic conditions were flat inceptisols. flat ultisols| and steep ultisols. Chemical analyses confirmed the existence of an almost three-fold gradient in total P and K in the upper I m of soil. We also annually censused all live woody stems greater than or equal to10 cm diameter above buttresses in each plot in September/October from 1997 to 2000 to obtain data on stand structure and dynamics. Fallen CWD stocks averaged 46.3 Mg ha(-1) (22.3 Mg C ha(-1))| while standing CWD averaged 6.5 Mg ha(-1) (3.1 Mg C ha(-1)). There were no significant differences in volume or mass of standing or fallen CWD among edaphic conditions. Annual inputs of CWD averaged 4.9 Mg ha(-1) (2.4 Mg C ha(-1)). Tumover time of fallen CWD was ca. 9 year. Neither stocks nor inputs were correlated with stand structure (number of trees per plot| plot basal area| or plot estimated above-ground biomass). Potential differences in CWD stocks and inputs among sites with different edaphic conditions may have been obscured by a 10-fold variation in tree mortality among plots and a two-fold variation in mean CWD input among years. Analysis of sample variance showed that stocks of CWD were adequately sampled with the 18 0.5 ha plot design. but that inputs were measured with low precision. At La Selva fallen and standing CWD stocks together equaled ca. 33% of estimated above-ground live woody biomass. Tropical rain forest CWD and its associated carbon are intermediate in pool size and turnover rate between fine litter and live trees. Our results show that scaling up TRF CWD estimates to larger spatial scales may be more constrained by the quality of data obtained over single landscapes than by variation due to zonal soil nutrient and topographic conditions. Both the magnitude and vagility of TRF CWD pools are likely to change with global climate change| but the overall direction of change is uncertain. (C) 2002 Elsevier Science B.V. All rights reserved. 5827,2002,3,3,Study of the characteristics of CH4 and N2O emission and methods of controlling their emission in the soil-trench wastewater treatment process,In recent years| worldwide concern over global warming has been expressed. It has been reported that domestic wastewater and its treatment processes are sources of CH4 and N2O| designated as greenhouse gases| the reduction of which was noted to be extremely important at the Third Conference of the Framework Convention on Climate Change (Conference Of the Parties; COP3). Here we report a study of a field that has been unexplored until now: analytical evaluation of the properties of the emission of CH4 and N2O and methods of restricting their emission in soil-trench wastewater treatment processes| the use of which is spreading| mainly in developing nations. The results have provided the following information. A field fact-finding survey has confirmed that soil trenches emit 9.3-13.9 g CH4 m(-3) and 8.2-12.2 gN(2)O m(-3) in Japan| and 3.0-4.5 g CH4 m(-3) and 3.3-5.0 g N2O m(-3) in China. The emission properties widely vary according to the structure of the treatment system. The conversion ratio for nitrogen in the wastewater influent to N2O by a soil trench is between 2 and a maximum of 8%| and ranges from a few- to several 10-fold as much as that with the activated sludge method| suggesting that this can be a large source of N2O emission. It has also clearly been shown that the aerobic-anaerobic state inside the treatment system is closely related to its CH4 and N2O emission characteristics. By performing ventilation to maintain the oxidation-reduction potential (ORP) near the trench at an aerobic condition of +200 mV or more| the quantities of CH4 and N2O emitted can be reduced by as much as 50% from the levels without this ventilation| and that this can make a large contribution. (C) 2002 Elsevier Science B.V. All rights reserved. 5725,2002,2,3,Summer dryness in a warmer climate: a process study with a regional climate model,Earlier GCM studies have expressed the concern that an enhancement of greenhouse warming might increase the occurrence of summer droughts in mid-latitudes| especially in southern Europe and central North America. This could represent a severe threat for agriculture in the regions concerned| where summer is the main growing season. These predictions must however be considered as uncertain| since most studies featuring enhanced summer dryness in mid-latitudes use very simple representations of the land-surface processes ("bucket" models)| despite their key importance for the issue considered. The current study uses a regional climate model including a land-surface scheme of intermediate complexity to investigate the sensitivity of the summer climate to enhanced greenhouse warming over the American Midwest. A surrogate climate change scenario is used for the simulation of a warmer climate. The control runs are driven at the lateral boundaries and the sea surface by reanalysis data and observations| respectively. The warmer climate experiments are forced by a modified set of initial and lateral boundary conditions. The modifications consist of a uniform 3 K temperature increase and an attendant increase of specific humidity (unchanged relative humidity). This strategy maintains a similar dynamical forcing in the warmer climate experiments| thus allowing to investigate thermodynamical impacts of climate change in comparative isolation. The atmospheric CO2 concentration of the sensitivity experiments is set to four times its pre-industrial value. The simulations are conducted from March 15 to October 1st| for 4 years corresponding to drought (1988)| normal (1986| 1990) and flood (1993) conditions. The numerical experiments do not present any great enhancement of summer drying under warmer climatic conditions. First| the overall changes in the hydrological cycle (especially evapotranspiration) are of small magnitude despite the strong forcing applied. Second| precipitation increases in spring lead to higher soil water recharge during this season| compensating for the enhanced soil moisture depletion occurring later in the year. Additional simulations replacing the plant control on transpiration with a bucket-type formulation presented increased soil drying in 1988| the drought year. This suggests that vegetation control on transpiration might play an important part in counteracting an enhancement of summer drying when soil water gets limited. Though further aspects of this issue would need investigating| our results underline the importance of land-surface processes in climate integrations and suggest that the risk of enhanced summer dryness in the region studied might be less acute than previously assumed| provided the North American general circulation does not change markedly with global warming. 2936,2002,3,4,Sustainability through green chemistry and engineering,The words "sustainability" and "sustainable development" are virtually omnipresent now. But how do we actually achieve the goals of sustainability| and what actions can we take? Green Chemistry and Engineering technologies are providing innovative solutions for today and tomorrow in many areas of product and process research and application. These technologies are helping to address some of the world's most pressing environmental issues| which include global climate change| sustainable energy production| food production and the associated agricultural practices| depletion of non-renewable resources| and the dissipation of toxic and hazardous materials in the environment. We describe the essential nature of Green Chemistry and Engineering in meeting these challenges and describe the specific examples and case studies that are presented in this book. 2852,2002,2,4,Synchronization of animal population dynamics by large-scale climate,The hypothesis that animal population dynamics may be synchronized by climate(1) is highly relevant in the context of climate change because it suggests that several populations might respond simultaneously to climatic trends if their dynamics are entrained by environmental correlation. The dynamics of many species throughout the Northern Hemisphere are influenced by a single large-scale climate system| the North Atlantic Oscillation (NAO)(2|3)| which exerts highly correlated regional effects on local weather(4). But efforts to attribute synchronous fluctuations of contiguous populations to large-scale climate are confounded by the synchronizing influences of dispersal or trophic interactions(5). Here we report that the dynamics of caribou and musk oxen on opposite coasts of Greenland show spatial synchrony among populations of both species that correlates with the NAO index. Our analysis shows that the NAO has an influence in the high degree of cross-species synchrony between pairs of caribou and musk oxen populations separated by a minimum of 1|000 km of inland ice. The vast distances| and complete physical and ecological separation of these species| rule out spatial coupling by dispersal or interaction. These results indicate that animal populations of different species may respond synchronously to global climate change over large regions. 2866,2002,5,4,Teaching about relict| no-analog landscapes,Only a few very young landforms are the result of currently operating geomorphic processes. Because the time scale for landscape evolution is much longer than the time scale for late Cenozoic climate changes| almost all landscapes are palimpsests| written over repeatedly by various combinations of climate-determined processes. Relict glacial and periglacial landforms are widely identified in mid-latitude regions that have been traditionally described as having been shaped by the "normal" processes of fluvial erosion. Less confidently| deeply weathered regolith and associated relict landforms in the middle and high latitudes are attributed to early Tertiary warmth. However| assemblages of geomorphic processes specific to certain climatic regions| like faunal and floral assemblages| cannot be translated across latitude| so in spite of the many books about the geomorphology of specific modem climate regions| there are few sources that discuss former warm high-latitude| or cold low-latitude| low-altitude geomorphic processes that have no modem analogs. Students and teachers alike who attempt to interpret landforms by extrapolating modem climatic conditions to other latitudinal zones will find their outlook broadened| and they become better prepared to consider the geomorphic impacts of global climate change. (C) 2002 Elsevier Science B.V. All rights reserved. 2930,2002,4,4,Techniques for estimating uncertainty in climate change scenarios and impact studies,Methodology for quantifying uncertainty in global climate change studies is reviewed| The focus is on recent developments in statistics| such as hierarchical modeling and Markov chain Monte Carlo simulation techniques| that could enable more full-fledged uncertainty analyses to be performed as part of integrated assessments of climate change and its impacts. First an overview of uncertainty analysis| including its sources and how it propagates| is provided. Presently employed techniques in climate change assessments| such as sensitivity| scenario| and Monte Carlo simulation analyses| are then surveyed. Next alternative approaches| based on more formal Statistical theory (especially the Bayesian statistical paradigm)| are described. Finally| some tentative recommendations on strategies for achieving the goal of more reliably quantifying uncertainty in global climate change are made. 5819,2002,5,3,Tectonic controls on greenhouse gas flux to the Paleogene atmosphere from the Gulf of Alaska accretionary prism,The late Paleocene to early Eocene (ca. 61-56 Ma) was a period of long-term global warming| perhaps the warmest in the Cenozoic. Recent modeling suggests that methane loading of the atmosphere| and related development of polar stratospheric clouds| could have been an important forcing mechanism for this period of warm climate. The Gulf of Alaska accretionary prism contained similar to6 x 10(6) km(3) of siliciclastic sediments deposited in trench and slope settings along Alaska's Maastrichtian and Paleogene continental margin. These sediments underwent complex deformation| accretion| and unusual high heat flow soon after deposition. Accretion processes thermally overmatured the sediments during a time that overlaps the 61-56 Ma period of long-term global warming. Assuming a modest average organic carbon content of 0.3 wt% in these sediments| an estimated 8.35 x 10(15) kg of methane were generated in the accretionary prism over an similar to5 m.y. period. This methane was not effectively trapped| and migration pathways to the atmosphere were developed through complexly deformed and emergent continental borderlands. The Gulf of Alaska accretionary prism is a possible source of the atmospheric methane needed to force Paleocene and early Eocene global warming and an example of how tectonic processes can significantly recycle carbon from the geosphere. 5793,2002,2,4,Temperature sensitivity of soil respiration and its effects on ecosystem carbon budget: nonlinearity begets surprises,Nonlinearity is a salient feature in all complex systems| and it certainly characterizes biogeochemical cycles in ecosystems across a wide range of scales. Soil carbon emission is a major source of uncertainty in estimating the terrestrial carbon budget at the ecosystem level and above. Due to the lack of consideration of the nonlinearity in temperature sensitivity of soil respiration| several commonly used ecosystem models produce substantially different estimates of soil respiration with the same or similar model input. In this paper we demonstrated that the response of soil respiration to changes in temperature sensitivity is nonlinear and. thus| that the oversimplified formulations may significantly reduce the accuracy of ecosystem models in predicting carbon fluxes. To alleviate this problem| we have developed a general model of temperature sensitivity of soil respiration that explicitly considers this nonlinearity. The model was supported by our field measurements from a forest ecosystem| and used to assess the uncertainty in estimating the soil CO2 efflux with several commonly used ecosystem models. Our results indicated that the variations and nonlinearity of the soil respiration-temperature relationship and its dependence on moisture may have important implications for ecosystem carbon modeling at regional and global scales. In other words| 'small causes' may lead to 'large effects' in complex ecosystems in terms of carbon dynamics. In particular| when the variability in temperature sensitivity of soil respiration was incorporated in the several commonly used ecosystem models| the carbon source-sink relationship for terrestrial ecosystems under future global warming scenarios became dramatically different from those reported previously. Thus| we advocate that confidence limits are both necessary and feasible for simulated carbon budget from ecosystem models. Based on field measurements and model simulations| our study provides useful information for computing such confidence limits. In addition| our new model of temperature sensitivity of soil respiration seems more general and yet realistic| and can improve the accuracy of ecosystem models in predicting carbon fluxes at large scales. (C) 2002 Elsevier Science B.V. All rights reserved. 5777,2002,2,4,Temperature| light| and the dimethylsulfoniopropionate (DMSP) content of Emiliania huxleyi (Prymnesiophyceae),The precursor of the volatile S-compound dimethylsulfide (DMS)| dimethylsulfoniopropionate (DMSP)| is produced by marine microalgae| notably by Prymnesiophyceae. The production of DMSP by an axenic isolate of Emiliania huxleyi (Lohm.) Hay et Mohler under different temperature and light conditions was studied as a first step towards understanding the role of DMSP-producing algae in climate regulation. Both light and temperature affected growth rate and cell size in batch cultures| but the concentration of DMSP in the cells was dependent on temperature only: at low temperature DMSP accumulated. This physiological response| assumed to be characteristic of DMSP-producing microalgae in general| is in line with the correlation that has been found between elevated concentrations of the DMS oxidation product MSA in ice core slices corresponding with low sea surface temperatures. Apparently| DMS does not play the role in climate regulation formulated in the CLAW hypothesis that proposes a feedback mechanism in which elevated temperatures lead to an increase in albedo via DMS-derived cloud condensation nuclei. (C) 2002 Elsevier Science B.V. All rights reserved. 2939,2002,4,4,Temporal and spatial variability of chlorophyll-a in the western subarctic Pacific determined from satellite and ship observations from 1997 to 1999,The objectives of this study are to describe and understand the processes controlling the temporal and spatial variability of chlorophyll-a (chl-a) in the subarctic northwestern Pacific Ocean from 1997 to 1999. Remotely sensed data from multi sensors| including ocean color (OCTS and SeaWiFS)| sea-surface temperature (SST| AVHRR)| and wind (SSM/I) datasets were utilized for the purpose of this study. Ocean-color imagery clearly showed seasonal and interannual variability in the spatial abundance and distribution of chl-a in the study area. Chl-a concentrations were generally low (0.53 +/- 0.24 mg m(-3)) for most part of the year| except for a few peaks (1.0-2.0 mg m(-3)) observed in the spring and fall bloom seasons (May| June| September| and October). Chl-a concentrations (> 10 mg m(-3)) were consistently high along the Kuril Islands and in the coastal waters around the Kamchatka Peninsula| and in 1998 they were clearly higher than in 1999. The Western Subarctic Gyre (WSG) was characterized by positive sea-surface temperature anomalies (SSTA) during the summer to fall of 1998. These anomalies appear to be a high-latitude response to 1997/1998 ENSO event. High concentrations of chl-a appeared in WSG in September-November only in 1998. We suggest that the high chl-a around the WSG from summer to fall in 1998 was facilitated by (1) negative SSTA in winter| in spite of the negative wind anomaly| which provided larger amount of nutrients to the sea surface| (2) positive wind anomaly from April to June| which might cause light limitation of the phytoplankton growth| due to deepening of the surface-mixed layer in summer| and (3) positive SSTA| even with the slightly positive wind anomaly| which was accompanied with the water-column stabilization and hence recovered light limitation of the phytoplankton. Warmer SST also might have enhanced the phytoplankton growth. During summer to fall in 1999| the phytoplankton biomass between 42degreesN and 43degreesN along 165degreesE was greater than in other years. The enhanced chl-a concentration coincided with a distinct frontal temperature gradient located between 40degreesN and 45degreesN in September 1998 and 1999. The peak chl-a concentration in September 1999 (> 2.0 mg m(-3)) within the temperature front was much larger than in L998 (about 0.7 mg m(-3)). The position of this front in September 1999 (41degreesN) was south of its position in 1998 (43degreesN). Convergence of chl-a is linked to the temperature gradient and southward expansion of well-mixed subarctic water that is cold| low in salinity| and nutrient-rich. Our results showed significant interannual biological variability| and illustrate how remote sensing with multi sensors can aid in monitoring relationships between local ecosystems and global climate change. (C) 2002 Elsevier Science Ltd. All rights reserved. 2877,2002,2,4,Temporal variability in arctic fox diet as reflected in stable-carbon isotopes; the importance of sea ice,Consumption of marine foods by terrestrial predators can lead to increased predator densities| potentially impacting their terrestrial resources. For arctic foxes (Alopex lagopus)| access to such marine foods in winter depends on sea ice| which is threatened by global climate change. To quantify the importance of marine foods (seal carrion and seal pups) and document temporal variation in arctic fox diet I measured the ratios of the stable isotopes of carbon (C-13/C-12) in hair of arctic foxes near Cape Churchill| Manitoba| from 1994 to 1997. These hair samples were compared to the stable carbon isotope ratios of several prey species. Isotopic differences between seasonally dimorphic pelage types indicated a diet with a greater marine content in winter when sea ice provided access to seal carrion. Annual variation in arctic fox diet in both summer and winter was correlated with lemming abundance. Marine food sources became much more important in winters with low lemming populations| accounting for nearly half of the winter protein intake following a lemming decline. Potential alternative summer foods with isotopic signatures differing from lemmings included goose eggs and caribou| but these were unavailable in winter. Reliance on marine food sources in winter during periods of low lemming density demonstrates the importance of the sea ice as a potential habitat for this arctic fox population and suggests that a continued decline in sea ice extent will disrupt an important link between the marine and terrestrial ecosystems. 5917,2002,3,4,Testing 100-year global warming potentials: Impacts on compliance costs and abatement profile,The comprehensive approach adopted in the Kyoto Protocol relies on the use of 100-year Global Warming Potentials (GWPs) to convert emissions of various gases to `carbon dioxide (CO2) equivalents'. This particular set of weights| or metric| has a limited capacity to handle the large variations in atmospheric adjustment times| and emissions of various gases that are equal in terms of `CO2 equivalents' will not result in equal climatic effects. In this study| the 100-year GWP metric is assessed in the context of implementing the Kyoto Protocol. Using data from Norway| we explore how abatement policy formulated on the basis of 100-year GWPs compares to policies based on other metrics in terms of compliance costs and abatement profile| that is| the composition of the basket of gases reduced. We found that the costs for Norway change significantly when other metrics are used| but changes in the composition of the basket of gases are moderate. However| since compliance costs can be controlled through other mechanisms for post-Kyoto Protocols| the use of 100-year GWPs versus other metrics has little impact on the general formulation of Norwegian climate policy. 5945,2002,4,4,The application of size-robust trend statistics to global-warming temperature series,In this note| new evidence is provided confirming that global temperature series spanning back to the mid-1800s have statistically significant positive trends. Although there is a growing consensus that global temperatures are on the rise systematically| some recent studies have pointed out that strong serial correlation (or a unit root) in global temperature data could| in theory| generate spurious evidence of a significant positive trend. In other words| strong serially correlated data can mimic trending behavior over fixed periods of time. A serial-correlation-robust trend test recently was proposed that controls for the possibility of spurious evidence due to strong serial correlation. This new test is valid whether the errors are stationary or have a unit root (strong serial correlation). This test also has the attractive feature that it does not require estimates of serial correlation nuisance parameters. The test is applied to six annual global temperature series| and it provides strong evidence that global temperature series have positive trends that are statistically significant even when controlling for the possibility of strong serial correlation. The point estimates of the rate of increase in the trend suggest that temperatures have risen about 0.5 degreesC (1.0 degreesF) 100 yr(-1). If the analysis is restricted to twentieth-century data| many of the point estimates are closer to 0.6 degreesC. 5830,2002,4,3,The background atmospheric concentrations of cyclic perfluorocarbon tracers determined by negative ion-chemical ionization mass spectrometry,The background atmospheric mixing ratios for a range of cyclic perfluorocarbons (cyclic-PFCs)| widely used in atmospheric dispersion studies| have been measured by gas chromatography-mass spectrometry in negative ion-chemical ionization mode. Background concentrations range from < 1 fl l(-1) to > 10fl l(-1)| where femtolitre is expressed as parts in 10(15) (ppqv). Because of their very long atmospheric lifetimes ( > 3000 yr) the present day concentrations represent the accumulated emissions from all sources| although significant commercial production did not commence until the 1960s. Cyclic-PFCs are potent greenhouse gases; however| their atmospheric concentrations are currently so low as to make an insignificant contribution to global warming. (C) 2002 Elsevier Science Ltd. All rights reserved. 5812,2002,2,4,The change in oceanic O-2 inventory associated with recent global warming,Oceans general circulation models predict that global warming may cause a decrease in the oceanic O-2 inventory and an associated O-2 outgassing. An independent argument is presented here in support of this prediction based on observational evidence of the ocean's biogeochemical response to natural warming. On time scales from seasonal to centennial| natural O-2 flux/heat flux ratios are shown to occur in a range of 2 to 10 nmol of O-2 per joule of warming| with larger ratios typically occurring at higher latitudes and overlongertime scales. The ratios are several times larger than would be expected solely from the effect of heating on the O-2 solubility| indicating that most of the O-2 exchange is biologically mediated through links between heating and stratification. The change in oceanic O-2 inventory through the 1990s is estimated to be 0.3 +/- 0.4 X 10(14) mol of O-2 per year based on scaling the observed anomalous long-term ocean warming by natural O-2 flux/heating ratios and allowing for uncertainty due to decadal variability. Implications are discussed for carbon budgets based on observed changes in atmospheric O-2/N-2 ratio and based on observed changes in ocean dissolved inorganic carbon. 2904,2002,5,4,The coastal oasis: ice age springs on emerged continental shelves,As ice caps expanded during each of the last five glaciations| sea level fell at least 120 m below current levels| exposing continental shelves worldwide to create vast areas of new land. As a result of this exposure| the ecology| climate| pedology| and geology of global shorelines were dramatically transformed| which in turn altered the carbon cycle and biodynamics of this new landmass. In this paper| we focus on a little-known hydrogeological phenomenon that may have had profound influences on biodiversity| human evolution| and carbon storage during periods of severe climatic stress of the Pleistocene Ice Ages. We propose that freshwater springs appeared on emerged continental shelves because falling sea level not only drew down and steepened the coastal water table gradient| thus increasing the hydrostatic head on inland groundwater aquifers| but also removed up to 120 m of hydrostatic pressure on the shelf| further enhancing groundwater flow. We call this phenomenon the "coastal oasis"| a model based on three well-established facts. (1) In all coastal areas of the world| continental aquifers discharge a continuous flow of fresh water to the oceans| (2) Many submarine sedimentary and morphological features| as well as seepages and flow of fresh water| are known on and below the shelves from petroleum explorations| deep-sea drilling programs| and mariners' observations. (3) Hydraulic principles (Darcy's law) predict increased groundwater flow at the coast when sea level drops because the piezometric head increases by the equivalent depth of sea-level lowering. Sea level is presently in a relatively high interglacial position. Direct observation and verification of our model is difficult and must rely on explorations of terrain that are now deeply submerged on continental shelves. For this reason| we draw parallels between our predicted model and simple| well-exposed terrestrial hydrological systems| such as present-day springs that appear on the exposed shores of lakes whose free-air water levels fell during periods of aridity. Such modem examples are seen in the Caspian Sea and Dead Sea| the Afar Depression| and the Sahara Desert. These modem analogues demonstrate the likelihood that underground water will be more abundant on emerged shelves during sea-level fall| causing springs| oases| and wetlands to appear. Our model creates an apparent paradox: in tropical and subtropical arid lands| such as most of Africa| sea-level fall during hyperarid glacial phases would produce abundant fresh water flow onto emerged continental shelves as the continental interior desiccated. Thus| emergent shoreline springs provided new habitats for terrestrial vegetation and animals displaced from the interior by increasingly arid conditions| shrinking ecosystems| and dwindling water supplies| Such a scenario would have had a profound influence on the vegetation that spreads naturally to colonize the emerged shelves during glacio-eustatic sea-level lowstands| as well as creating new habitats for terrestrial mammals| including early humans. (C) 2002 Elsevier Science B.V. All rights reserved.
5960,2002,4,3,The domino effect in climate change,This paper provides a concise summary of the natural and the anthropogenic greenhouse effect and the major causes for climate change. This summary may be particularly accessible for readers who are not familiar with natural sciences. Building on these explanations| we develop a simplifying atmospheric model that demonstrates a widely unknown aspect of global warming: the greenhouse effect enhances its own causes and| as a repercussion| induces a further global warming. This effect| referred to as domino effect| is based on the additional production of heat in the atmosphere| happening substantively while heat passes our atmosphere on its way to outer space. On the basis of our considerations| in principle| technological efficiency improvements appear to be an attractive measure for mitigating global warming. 2916,2002,2,4,The effect of single tree species on soil microbial activities related to C and N cycling in the Siberian artificial afforestation experiment - Tree species and soil microbial activities,The effects of grassland conversion to forest vegetation and of individual tree species on microbial activity in Siberia are largely unstudied. Here| we examined the effects of the six most commonly dominant tree species in Siberian forests (Scots pine| spruce| Arolla pine| larch| aspen and birch) on soil C and N mineralization| N2O-reduction and N2O production during denitrification 30 years after planting. We also documented the effect of grassland conversion to different tree species on microbial activities at different soil depths and their relationships to soil chemical properties. The effects of tree species and grassland conversion were more pronounced on N than on C transformations. Tree species and grassland conversion did significantly alter substrate-induced respiration (SIR) and basal respiration| but the differences were not as large as those observed for N transformations. Variances in SIR and basal respiration within species were markedly lower than those in N transformations. Net N mineralization| net nitrification| and denitrification potential were highest under Arolla pine and larch| intermediate under deciduous aspen and birch| and lowest beneath spruce and Scots pine. Tree species caused similar effects on denitrification potential| net N mineralization| and net nitrification| but effects on N2O reduction rate were idiosyncratic| indicating a decoupling of N2O production and reduction. We predict that deciduous species should produce more N2O in the field than conifers| and that Siberian forests will produce more N2O if global climate change alters tree species composition. Basal respiration and SIR showed inverse responses to tree species: when basal respiration increased in response to a given tree species| SIR declined. SIR may have been controlled by NH4+ availability and related therefore to N mineralization| which was negatively affected by grassland conversion. Basal respiration appeared to be less limited by NH4+ and controlled mostly by readily available organic C (DOC)| which was higher in concentration under forests than in grassland and therefore basal respiration was higher in forested soils. We conclude that in the Siberian artificial afforestation experiment| soil C mineralization was not limited by N. 5955,2002,2,5,The effect of solar activity on carbon dioxide concentration in the lower atmosphere,In the last few years| the carbon dioxide content has been increasing from year to year| possibly due to human activity| and could be an artificial source of global warming. Evidence of a statistically reliable effect of solar activity on the variations in the CO2 content in the lower atmosphere has been presented| and the global increase in CO2| depending on the GCR flux and solar activity| is explained. 5775,2002,2,4,The effects of large-scale afforestation and climate change on water allocation in the Macquarie River catchment| NSW| Australia,Widespread afforestation has been proposed as one means of addressing the increasing dryland and stream salinity problem in Australia| However| modelling results presented here suggest that large-scale tree planting will substantially reduce river flows and impose costs on downstream water users if planted in areas of high runoff yield. Streamflow reductions in the Macquarie River| NSW| Australia are estimated for a number of tree planting scenarios and global warming forecasts. The modelling framework includes the Sacramento rainfall-runoff model and IQQM| a streamflow routing tool| as well as various global climate model outputs from which daily rainfall and potential evaporation data files have been generated in OzClim| a climate scenario generator. For a 10% increase in tree cover in the headwaters of the Macquarie| we estimate a 17% reduction in inflows to Burrendong Dam. The drying trend for a mid-range scenario of regional rainfall and potential evaporation caused by a global warming of 0.5degreesC may cause an additional 5% reduction in 2030| These flow reductions will decrease the frequency of bird-breeding events in Macquarie Marshes (a RAMSAR protected wetland) and reduce the security of supply to irrigation areas downstream. Inter-decadal climate variability is predicted to have a very significant influence on catchment hydrologic behaviour. A further 20% reduction in flows from the long-term historical mean is possible| should we move into an extended period of below average rainfall years| such as occurred in eastern Australia between 1890 and 1948. Because current consumptive water use is largely adapted to the wetter conditions of post 1949| a return to prolonged dry periods would cause significant environmental stress given the agricultural and domestic water developments that have been instituted. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved. 5679,2002,2,4,The evolution of extreme temperatures in the Central England temperature record,[1] The Central England daily mean temperature record (CET) extends from 1772 to present. An extreme value analysis based on the Generalized Pareto distributions shows that both cold winter and hot summer extremes have evolved differently from their means. The reasons for the trends in extremes occurrence are related to changes in the underlying atmospheric circulation. Of particular interest are the winter extreme cold days. In recent years| around 80% of these occurred on anticyclonic or easterly type days| compared to only 50% at the beginning of the 20th century. This change is related to cooling temperatures on these type days since the 1930s. Such a trend has placed an effective cap on any upward trend in winter cold extremes related to global warming so far. 5868,2002,4,4,The Gaia hypothesis: Fact| theory| and wishful thinking,Organisms can greatly affect their environments| and the feedback coupling between organisms and their environments can shape the evolution of both. Beyond these generally accepted facts| the Gaia hypothesis advances three central propositions: (1) that biologically mediated feedbacks contribute to environmental homeostasis| (2) that they make the environment more suitable for life| and (3) that such feedbacks should arise by Darwinian natural selection. These three propositions do not fare well under close scrutiny. (1) Biologically mediated feedbacks are not intrinsically homeostatic. Many of the biological mechanisms that affect global climate are destabilizing| and it is likely that the net effect of biological feedbacks will be to amplify| not dampen| global warming. (2) Nor do biologically mediated feedbacks necessarily enhance the environment| although it will often appear as if this were the case| simply because natural selection will favor organisms that do well in their environments - which means doing well under the conditions that they and their co-occurring species have created. (3) Finally| Gaian feedbacks can evolve by natural selection| but so can anti-Gaian feedbacks. Daisyworld models evolve Gaian feedback because they assume that any trait that improves the environment will also give a reproductive advantage to its carriers (over other organisms that share the same environment). In the real world| by contrast| natural selection favors any trait that gives its carriers a reproductive advantage over its non-carriers| whether it improves or degrades the environment (and thereby benefits or hinders its carriers and non-carriers alike). Thus Gaian and anti-Gaian feedbacks are both likely to evolve. 5859,2002,2,4,The genome of M-acetivorans reveals extensive metabolic and physiological diversity,Methanogenesis| the biological production of methane| plays a pivotal role in the global carbon cycle and contributes significantly to global warming. The majority of methane in nature is derived from acetate. Here we report the complete genome sequence of an acetate-utilizing methanogen| Methanosarcina acetivorans C2A. Methanosarcineae are the most metabolically diverse methanogens| thrive in a broad range of environments| and are unique among the Archaea in forming complex multicellular structures. This diversity Is reflected In the genome of M. acetivorans. At 5|751|492 base pairs it is by far the largest known archaeal genome. The 4524 open reading frames code for a strikingly wide and unanticipated variety of metabolic and cellular capabilities. The presence of novel methyltransferases indicates the likelihood of undiscovered natural energy sources for methanogenesis| whereas the presence of single-subunit carbon monoxide dehydrogenases raises the possibility of nonmethanogenic growth. Although motility has not been observed in any Methanosarcineae| a flagellin gene cluster and two complete chemotaxis gene clusters were identified. The availability of genetic methods| coupled with its physiological and metabolic diversity| makes M. acetivorans a powerful model organism for the study of archaeal biology. 2880,2002,4,3,The influence of land-use change and landscape dynamics on the climate system: relevance to climate-change policy beyond the radiative effect of greenhouse gases,Our paper documents that land-use change impacts regional and global climate through the surface-energy budget| as well as through the carbon cycle. The surface-energy budget effects may be more important than the carbon-cycle effects. However| land-use impacts on climate cannot be adequately quantified with the usual metric of 'global warming potential'. A new metric is needed to quantify the human disturbance of the Earth's surface-energy budget. This 'regional climate change potential' could offer a new metric for developing a more inclusive climate protocol. This concept would also implicitly provide a mechanism to monitor potential local-scale environmental changes that could influence biodiversity. 5899,2002,2,4,The influence of thermal ecology on the distribution of three nymphalid butterflies,1. Studies have shown that many adult and immature insects are able to maintain body temperature well above| and often independently of| ambient temperature in the presence of direct solar radiation. They may do so directly by basking| or indirectly via microhabitat choice| The implications for this are often ignored in development models that serve to predict species' responses to climate change. 2. To investigate the difference in development times attributable to solar input| field development of Aglais urticae| Inachis io and Polygonia c-album larvae (Lepidoptera: Nymphalidae) was followed both in a natural open situation and in an artificially shaded environment. Each species completed development more quickly in the open| equivalent to a 20%| 10% and 15% reduction in development time| respectively. 3. Observed development times in the artificially shaded environment were used to compare the techniques of rate summation and degree-day modelling. Rate summation models were found to describe development in the shade best for A. urticae and I. io| although a degree-day model performed best for P c-album| possible reasons for which are discussed. The best-performing models for each species were modified to include larval thermo regulation data| assuming a linear relationship between body and ambient temperatures during the measured sunshine hours each day| and tested against observed development times in the open situation. Times for 50% adult emergence were predicted exactly for A. urticae| and to an accuracy of 1 day for I. io and 5 days for P c-album. 4. The models were tested further using climate data from 128 UK Meteorological Office weather stations across England| Wales and Scotland. Thermo regulation model predictions matched observed UK distribution and voltinism better than predictions made by the standard unmodified models. It was estimated that larval thermoregulation allows A. urticae and 1. io populations to persist approximately 200 km further north than would otherwise be possible| and that the extent of bivoltinism may be shifted northwards by around 300 km. 5. These results have significant implications for predicting the effects of global warming on insects' geographical ranges| the potential distributions of invasive species| and the phenology and voltinism of introduced biocontrol agents as one component of their likely success. 5897,2002,3,4,The inhibition of marine nitrification by ocean disposal of carbon dioxide,In an attempt to reduce the threat of global warming| it has been proposed that the rise of atmospheric carbon dioxide concentrations be reduced by the ocean disposal of CO2 from the flue gases of fossil fuel-fired power plants. The release of large amounts Of CO2 into mid or deep ocean waters will result in large plumes of acidified seawater with pH values ranging from 6 to 8. In an effort to determine whether these CO2-induced pH changes have any effect on marine nitrification processes| surficial (euphotic zone) and deep (aphotic zone) seawater samples were sparged with CO2 for varying time durations to achieve a specified pH reduction| and the rate of microbial ammonia oxidation was measured spectrophotometrically as a function of pH using an inhibitor technique. For both seawater samples taken from either the euphotic or aphotic zone| the nitrification rates dropped drastically with decreasing pH. Relative to nitrification rates in the original seawater at pH 8| nitrification rates were reduced by ca. 50% at pH 7 and more than 90% at pH 6.5. Nitrification was essentially completely inhibited at pH 6. These findings suggest that the disposal Of CO2 into mid or deep oceans will most likely result in a drastic reduction of ammonia oxidation rates within the pH plume and the concomitant accumulation of ammonia instead of nitrate. It is unlikely that ammonia will reach the high concentration levels at which marine aquatic organisms arc known to be negatively affected. However. if the ammonia-rich seawater from inside the pH plume is upwelled into the euphotic zone| it is likely that changes in phytoplankton abundance and community structure will occur. Finally| the large-scale inhibition of nitrification and the subsequent reduction of nitrite and nitrate concentrations could also result in a decrease of denitrification rates which| in turn| could lead to the buildup of nitrogen and unpredictable eutrophication phenomena. Clearly. more research on the environmental effects of ocean disposal of CO2 is needed to determine whether the potential costs related to marine ecosystem disturbance and disruption can be justified in terms of the perceived benefits that may be achieved by temporarily delaying global warming. (C) 2002 Elsevier Science Ltd. All rights reserved. 2923,2002,4,3,The oxidation of organic compounds in the troposphere and their global warming potentials,Oxidation by hydroxyl radicals is the main removal process for organic compounds in the troposphere. This oxidation acts as a source of ozone and as a removal process for hydroxyl and peroxy radicals| thereby reducing the efficiency of methane oxidation and promoting the build-up of methane. Emissions of organic compounds may therefore lead to the build-up of two important radiatively-active trace gases: methane and ozone. Emission pulses of 10 organic compounds were followed in a global 3-D Lagrangian chemistry-transport model to quantify their indirect greenhouse gas impacts through changes induced in the tropospheric distributions of methane and ozone. The main factors influencing the global warming potentials of the 10 organic compounds were found to be their spatial emission patterns| chemical reactivity and transport| molecular complexity and oxidation products formed. The indirect radiative forcing impacts of organic compounds may be large enough that ozone precursors should be considered in the basket of trace gases through which policy-makers aim to combat global climate change. 5834,2002,2,4,The potential impact of climate change on Taiwan's agriculture,This paper intends to estimate the potential impact of climate change on Taiwan's agricultural sector. Yield response regression models are used to investigate the climate change's impact on 60 crops. A price-endogenous mathematical programming model is then used to simulate the welfare impacts of yield changes under various climate change scenarios. Results suggest that both warming and climate variations have a significant but non-monotonic impact on crop yields. Society as a whole would not suffer from warming| but a precipitation increase may be devastating to farmers. (C) 2002 Elsevier Science B.V. All rights reserved. 5893,2002,2,4,The proposed connection between clouds and cosmic rays: cloud behaviour during the past 50-120 years,Several authors have suggested that a link exists between the flux of galactic cosmic rays (GCR) and cloudiness. Here we review the evidence for such a connection from studies of cloud factors using both satellite and ground-based data. In particular| we search for evidence for the low cloud decrease predicted by the rising levels of solar activity and the low cloud-cosmic ray flux correlation indicated by satellite data. Sunshine and synoptic cloud records both indicate that the global total cloud cover has increased during the past century. This increase in total cloud cover argues against a dominating role by solar activity (via GCR) over cloud formation on centennial time scales. Either the predicted low cloud decrease has not occurred or the medium-high level cloud has increased to a greater extent than low cloud has decreased. As there is no accurate long term data available on low cloud behaviour during the last century| we are not able to totally dismiss the link between GCR and cloudiness| but we list a number of arguments for and against the proposed cosmic ray-cloud connection. (C) 2002 Elsevier Science Ltd. All rights reserved. 5697,2002,2,4,The relative impacts of daytime and night-time warming on photosynthetic capacity in Populus deltoides,In order to investigate the relative impacts of increases in day and night temperature on tree carbon relations| we measured night-time respiration and daytime photosynthesis of leaves in canopies of 4-m-tall cottonwood (Populus deltoides Bartr. ex Marsh) trees experiencing three daytime temperatures (25| 28 or 31 degreesC) and either (i) a constant nocturnal temperature of 20 degreesC or (ii) increasing nocturnal temperatures (15| 20 or 25 degreesC). In the first (day warming only) experiment| rates of night-time leaf dark respiration (R-dark) remained constant and leaves displayed a modest increase (11%) in light-saturated photosynthetic capacity (A(max)) during the day (1000-1300 h) over the 6 degreesC range. In the second (dual night and day warming) experiment| R-dark increased by 77% when nocturnal temperatures were increased from 15 degreesC (0.36 mumol m(-2) s(-1)) to 25 degreesC (0.64 mumol m(-2) s(-1)). A(max) responded positively to the additional nocturnal warming| and increased by 38 and 64% in the 20/28 and 25/31 degreesC treatments| respectively| compared with the 15/25 degreesC treatment. These increases in photosynthetic capacity were associated with strong increases in the maximum carboxylation rate of rubisco (V-cmax) and ribulose-1|5-bisphosphate (RuBP) regeneration capacity mediated by maximum electron transport rate (J(max)). Leaf soluble sugar and starch concentration| measured at sunrise| declined significantly as nocturnal temperature increased. The nocturnal temperature manipulation resulted in a significant inverse relationship between Amax and pre-dawn leaf carbohydrate status. Independent measurements of the temperature response of photosynthesis indicated that the optimum temperature (T-opt) acclimated fully to the 6 degreesC range of temperature imposed in the daytime warming. Our findings are consistent with the hypothesis that elevated night-time temperature increases photosynthetic capacity during the following light period through a respiratory-driven reduction in leaf carbohydrate concentration. These responses indicate that predicted increases in night-time minimum temperatures may have a significant influence on net plant carbon uptake. 5875,2002,3,2,The relative importance of sources of greenhouse-gas emissions: Comparison of global through subnational perspectives,Increasing atmospheric concentrations of greenhouse gases are widely expected to cause global warming and other climatic changes. It is important to establish priorities for reducing greenhouse-gas emissions| so that resources can be allocated efficiently and effectively. This is a global problem| and it is possible| on a global scale| to identify those activities whose emissions have the greatest potential for enhancing the greenhouse effect. However| perspectives from smaller scales must be appreciated| because it is on scales down to the local level that response measures will be implemented| This paper analyzes the relative importance of emissions from the many individual sources| on scales ranging from global to national to subnational. Individual country perspectives and proposed policy measures and those of subnational political entities exhibit some commonalities but differ among themselves and from a global-scale perspective in detail. 5926,2002,4,4,The role of sapwood temperature variations within Pinus cembra on calculated stem respiration: Implications for upscaling and predicted global warming,Only a few studies focused on variations in stem respiration within entire trees related to variations within sapwood temperature. In this study| sapwood temperature was measured in 1 cm depth at four positions in the stem of a 50-year-old cembran pine (Pinus cembra L.) throughout the year 1995. These temperature data were used to estimate variations in CO2 efflux within the stem| assuming that the temperature dependence of respiration was constant and that there is no difference in the number of living cells in the xylem throughout the entire stem. Respiration was compared on a surface area basis. South-facing sapwood temperatures were significantly higher than air temperature when compared to north-facing sapwood temperature. As a consequence annual respiration was up to 13% higher on the south than on the north side of the tree. Thus| within-stem variations in temperature have been taken into account when scaling up stem respiration from data obtained from one individual position within a tree. 2884,2002,4,4,The role of science in federal policy development on a regional to global scale: Personal commentary,Nutrient enrichment of coastal waters is an example of the large-scale| highly complex environmental challenges facing decision makers today. Conventional monitoring networks and advanced observational capabilities permit the detection of changes in the environment at continental to global scales (e.g.| hypoxia in the Gulf of Mexico| aerosol plumes stretching across the ocean| global atmospheric enrichment of carbon dioxide). Much more knowledge is needed| however| to fully understand the societal consequences of environmental change and of actions taken to address diem. This paper discusses the emerging role of assessment in developing effective U.S. policy responses to large-scale| complex environmental change while improving the scientific understanding of the problem. In the cases of global climate change and coastal hypoxia| the U.S. Congress passed legislation authorizing assessments recognizing that decision making must proceed in the face of scientific uncertainty. Evaluating the state of knowledge is usually the first step in an assessment in order to provide a picture of what is known and where there are knowledge gaps. Assessments should also provide the policy maker with an idea of the level of uncertainty| how long it may take to reduce the uncertainty| what information is most critical to resolve| and the consequences and benefits of the various management options. In this paper I draw upon several examples from national assessments| including those of climate change impacts on the U.S. and relationships between Mississippi River water and Gulf of Mexico water quality| to illustrate the strengths and difficulties of using science and assessment to inform the policy process. 5782,2002,2,3,The roles of radiation and dynamical processes in the El Nino-like response to global warming,The current understanding of ENSO does not foreshadow how it might change as a consequence of global warming due to an increase in atmospheric greenhouse gas (GHG) concentration. A number of global coupled climate models simulate a "mean" El Nino-like change in tropical Pacific temperatures| precipitation| and winds but at least one model exhibits a La Nina-like pattern and others a more or less homogeneous warming in the tropics with little of either pattern. The mechanisms leading to a mean positive El Nino-like pattern (PEP) are studied in simulations with the Canadian Centre for Climate Modeling and Analysis (CCCma) coupled general circulation model. The changes associated with the PEP are compared with| and are shown to closely resemble| those observed for the positive El Nino phase of the ENSO oscillation in the current climate including the anomalies in SST| precipitation and atmospheric circulation| the changes of vertically integrated energy and heat transports in the atmosphere| and changes in the sign and magnitude of radiative energy balance terms. The PEP in the model is supported by changes in oceanic heat transport and surface longwave radiative flux in the face of solar radiative flux and evaporative flux changes which act to damp it away. There is negative cloud-radiation feedback associated with the PEP| as with the observed El Nino. Negative cloud feedback by itself does not| therefore| preclude the existence of a PEP response to GHG forcing. The climatological PEP does not exhibit an oceanic export of energy from the tropical Pacific. as inferred for the regular El Nino| event| but rather an oceanic import of energy. Nevertheless the PEP provides an effective means of regulating climate warming and the energy budget in the tropical Pacific which is accomplished through energy transports out of the region by the atmosphere. The PEP is seen as a more or less straightforward manifestation of the feedback mechanism proposed by Bjerknes and as a physically plausible response to GHG-induced climate warming. 5890,2002,3,3,The time path and implementation of carbon sequestration,We develop a dynamic model to investigate the optimal time paths of carbon emissions| sequestration| and the carbon stock. We show that carbon sinks should be utilized as early as possible| and carbon flow into sinks should last until the atmospheric carbon concentration is stabilized. We rule out any cyclical patterns of carbon sequestration and release. We propose and assess three mechanisms to efficiently introduce sequestration into a carbon permit trading market: a pay-as-you-go system| a variable-length-contract system and a carbon annuity account system. Although the three mechanisms may not be equally feasible to implement. they are all efficient. 5892,2002,4,4,The use of remote sensing for predictive modeling of schistosomiasis in China,The development of predictive models of the spatial distribution of schistosomiasis are hampered by the existence of different regional subspecies of the Oncomelania hupensis snail that serve as intermediate hosts for the disease in China. The habitats associated with these different subspecies vary considerably| with mountainous habitats in the west and floodplain habitats in the east. Despite these challenges| continuing environmental change resulting from the construction of the Three Gorges Dam and global warming that threaten to increase snail habitat| as well as limited public health resources| require the ability to accurately map and prioritize areas at risk for schistosomiasis. This paper describes a series of ongoing studies that rely on remotely sensed data to predict schistosomiasis risk in two regions of China. The first study is a classification of Landsat TM imagery to identify snail habitats in mountainous regions of Sichuan Province. The accuracy of this classification was assessed in an independent field study| which revealed that seasonal flooding may have contributed to misclassification| and that the incorporation of soil maps may greatly improve classification accuracy. A second study presents the use of Landsat TM and water level data to understand seasonal differences in Oncomelania hupensis habitat in the lower Yangtze River region. 5858,2002,3,4,The use of unsaturated fluorocarbons for dielectric etch applications,Six unsaturated fluorocarbon (UFC) gases as well as a fluorinated ether were examined for dielectric etch and global warming emissions performance and compared to three perfluorocompound (PFC) gases. All of the gases were capable of etch performance comparable to that of a typical C3F8 process| while exhibiting superior global warming emissions performance compared to the PFCs. A low-flow hexafluoro-2-butyne process was found to have a significant emissions benefit| showing a normalized emissions reduction of 88.2% compared to the C3F8 process. Two other C4F6 isomers (h)exafluoro-1|3-butadiene and hexafluorocyclobutene! also exhibited reductions greater than 80%| while hexafluoropropene and octafluorocyclopentene exhibited emissions reductions greater than 70% compared to the typical C3F8 process. For the C4F6 isomers| a large portion of the emissions were a result of CHF3 formation with photoresist as the sole source of the hydrogen. An extended 4 min etch with hexafluoro-1|3-butadiene resulted in a deep via with an aspect ratio of 5: 1| very high selectivity to photoresist| and no evidence of etch stopping. (C) 2002 The Electrochemical Society. 2943,2002,4,4,Tiger-program for thermospheric-ionospheric geospheric research - Long-term measurement of solar EUV/UV fluxes for thermospheric-ionospheric (T/I) modelling and for space weather investigations,On 18/19 June 1998 the 1st TIGER Symposium was held in Freiburg/Germany. After presentation and discussion of 28 invited and contributed talks| the symposium agreed to establish a longterm TIGER Program within the framework of the SCOSTEP International Solar Cycle Study Working Group 1| Panel 2. This decision is based on the general agreement that| for thermospheric-ionosphenic research as well as for a broad range of commercial applications in space| the improvement of existing thermosphenic-ionospheric (T/I) models is absolutely necessary to meet scientific goals. There are a number of scientific questions underlying the goal of understanding solar EUV/UV variability such as what are the primary mechanisms by which solar ultraviolet (UV)| extreme ultraviolet (EUV)| and soft X-ray (XUV) irradiance variations affect terrestrial global climate change and/or weather and what is their significance? How does solar forcing compare with that from other sources such as increasing concentrations of radiatively-active gases and atmospheric aerosols? How sensitive is the Earth's climate to changes in solar radiation? What time scales of solar variability are significant to climate? How might solar variability in these wavelengths affect global warming projections? Are there signatures of solar influences in the upper atmosphere that are distinct from anthropogenic effects? To meet these goals| coordinated work on the following topics is required and is discussed in detail below: 1. Measurement and modelling of solar EUV/UV radiation 2. Measurement and modelling of the solar wind (particles) originated energy T/I influx 3. Measurement of relevant thermospheric-ionospheric parameters 4. Modelling of the thermosphere/ionosphere 5. Fundamental physical investigations of photoenergetic atomic and molecular processes To make substantial progress in developing a complete understanding of the T/I processes| it is necessary to envisage solar cycle and longer timescales. This can be done in the global change context by making use of a broad range of worldwide existing resources with respect to manpower| experience| hardware| methods| flight opportunities| and funding resources. The TIGER Program alms to facilitate the coordination of these existing and planned activities and to help define missing links for achieving the scientific goals. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. 5853,2002,4,3,Time preference in global warming calculations: a proposal for a unified index,Many aspects of the calculation of the impacts of greenhouse gas (GHG) emissions and the costs and benefits of possible response options are highly sensitive to the way in which time preference is incorporated into the computations. The Intergovernmental Panel on Climate Change (IPCC) used global warming potentials (GWPs) to standardize inputs of different gases with differing radiative forcings and atmospheric lifetimes; in the results emphasized by the IPCC's Second Assessment Report| a 100-year time horizon and no discounting is used| and this has been adopted by the Kyoto Protocol for use in the first commitment period (2008-2012). Here an alternative unified index is proposed that assigns explicit weights to the interests of different generations. In contrast to discounting (including the zero discount rate used by the IPCC)| the generationally weighted index forces policy makers to face the moral assumptions that underlie their choices related to global warming. (C) 2002 Elsevier Science B.V. All rights reserved. 2856,2002,2,4,Time series remote sensing of landscape-vegetation interactions in the southern Great Plains,The southern Great Plains may be one of the first areas in the United States to show significant and detectable changes in vegetation cover as a result of global climate change. The objective of this project was to examine interactions between landscape environmental factors and interannual variability of land-cover types in this region| Harmonic analysis of a nine-year time series (1989-1997) of NOAA Advanced Very High Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI) biweekly composite data was used to quantify interannual changes in natural and managed| vegetation. An index of interannual landscape variability was developed based on the weighted circular variance in phase values produced by the harmonic analysis. Results indicate that landscape variability| as quantified by the weighted circular variance| is significantly different among three soil texture classes and five land-use/land-cover types. Harmonic analysis of time-series data offers considerable promise as a tool for monitoring landscape change. 2934,2002,5,4,Timing and style of Late Quaternary glaciation in the eastern Hindu Kush| Chitral| northern Pakistan: a review and revision of the glacial chronology based on new optically stimulated luminescence dating,Glacial landforms and sediments provide evidence for two Late Quaternary major glaciations in the eastern Hindu Kush. New optically stimulated luminescence (OSL) dating was undertaken to define the timing of these glaciations and associated sediment deposition. The Drosh Glacial| was defined by OSL dating to have occurred during marine isotopic stage-3| producing an extensive valley glaciation that extended to an altitude of greater than or equal to1300 m above sea level (asl) in the main valley| with an equilibrium line altitude (ELA) depression of similar to1200 m. The Pret Glacial produced a valley glaciation that extended to an altitude of similar to1670 m asl. in the main valley| with an ELA depression of similar to1000 m. The new OSL dating suggests that this glacial stage probably represents several glacial advances that occurred during the latter part of the Last Glacial. Moraines representing two minor glacial advances| the Shandur and Barum Glacial stages| were also recognized near the contemporary glaciers. These probably formed during the Middle/Late Holocene and Little Ice Age| respectively. This study and comparisons with adjacent regions suggest that there was limited glaciation during the global Last Glacial Maximum (LGM) in the Hindu Kush. Deglaciation in the mountain ranges of the Himalayas and the consequent meltwater discharge into the adjacent seas was negligible immediately after the global LGM and it was therefore of minor importance as a forcing factor for global climate change during the end of the last glacial cycle. However| our studies show that glaciation and particularly deglaciation is important in controlling the deposition of thick valley fills and the landscape evolution of the high mountain environments. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved. 5762,2002,4,4,Total aboveground biomass in central Amazonian rainforests: a landscape-scale study,Amazonian forests play a key role in the global carbon cycle| but there is much uncertainty about the quantity and distribution of carbon stored in these forests. We quantified total aboveground dry biomass (TAGB) in undisturbed central Amazonian rainforests| based on detailed estimates of all live and dead plant material within 20 1 ha plots spanning an extensive (ca. 1000 km(2)) study area. TAGB values in our study area were very high| averaging 397.7 +/- 30.0 Mg ha(-1). The most important component of aboveground biomass was large (greater than or equal to10 cm diameter-at-breast-height (DBH)) trees| which comprised 81.9% of TAGB| followed by downed wood debris (7.0%)| small trees| saplings| and seedlings (<10 cm DBH; 5.3%)| lianas (2.1%)| litter (1.9%)| snags (1.5%)| and stemless palms (0.3%). Among large trees| aboveground biomass was greatest in intermediate-sized (20-50 cm DBH) stems (46.7% of TAGB)| with very large (greater than or equal to60 cm DBH) trees also containing substantial biomass (13.4% of TAGB). There were no significant correlations between large tree biomass and that of any other live or dead biomass component. An analysis based on the variability of our samples suggested that just 3-4 randomly positioned I ha plots would be sufficient to provide a reasonable estimate of mean TAGB in a landscape such as ours (with 95% confidence intervals being <10% of the mean). This suggests that efforts to quantify Amazon forest biomass should be extensive rather than intensive; researchers should sample many geographically separate areas with a few plots each| rather than sampling a small number of areas more intensively. Published by Elsevier Science B.V. 5881,2002,3,3,Total organic carbon losses in subsurface flow under two management practices,Greenhouse gases and global warming have become major topics. Much of the greenhouse gas discussion has dealt with carbon dioxide (CO2) and methods to sequester or store atmospheric carbon in soils and forests. The entire carbon cycle needs to be studied to better understand the overall process. The major carbon transformations are loss of CO2 to the atmosphere or the storage of carbon in sinks such as soil. Although it is a minor pathway| carbon leached through the soil and into groundwater needs to be quantified. Numerous carbon studies have been performed| but concentrations and losses of total organic carbon (TOC) moving through a soil profile have received little attention. Therefore| this study was to assess TOC levels in subsurface flow under two management practices. TOC was determined monthly in the percolate from large Soil blocks| called lysimeters| (2.4 m [8 ft] deep) with undisturbed soils under row crops. Most of the TOC concentrations in the percolate ranged from 0.5 to 6.0 mg/L with the corn/soybean-rye rotation. Developed springs in two rotational grazing systems were sampled for 10 years. TOC concentrations in the groundwater from the spring flow developments had less variability than in the lysimeter percolate. Most TOC values from these pasture systems were in a concentration range of 1 to 3 mg/L. Annual averages of TOC transport were similar for the lysimeter percolate and groundwater springs| ranging from 3.7 to 6.o kg/ha (3-3 to 5.4 lb/ac). 2924,2002,3,3,Tradeable carbon permit auctions - How and why to auction not grandfather,An auction of carbon permits is the best way to achieve domestic carbon caps designed to limit global climate change. To minimize administrative costs| permits would be required at the level of oil refineries| natural gas pipe lines| natural gas liquid sellers. and coal processing plants. To maximize liquidity in secondary markets. permits would be fully tradable and bank-able. The government would conduct quarterly auctions. A standard ascending-clock auction in which price is gradually raised until there is no excess demand would provide reliable price discovery. An auction is preferred to grandfathering (giving companies permits based on historical output or emissions)| because it allows reduced tax distortions| provides more flexibility in distribution of costs| provides greater incentives for innovation. and reduces the need for politically contentious arguments over the allocation of rents.
5722,2002,2,3,Trends and fluctuations in the dates of ice break-up of lakes and rivers in Northern Europe: the effect of the North Atlantic Oscillation,The existence of an ice cover has important effects on the streamflow conditions as well as on the hear transfer between water bodies and the overlying atmosphere| This paper investigates the effects of climate variability on the termination of the ice season in the Baltic region. In particular| trends and fluctuations observed in the cryophenological records from this region are analyzed in detail| searching for possible connections with the North Atlantic Oscillation (NAO). The NAO seems to affect mostly the late-winter temperature (January-March) with a significant impact also on the mid-spring (April-May) period| when the air temperature is strongly correlated to the ice dates. A regional analysis shows the existence in the series of winter temperature (JFM) of the same fluctuations as the winter NAO. The same components can be found in the cryophenological records and (partly) in the series of spring temperature. Nevertheless| both ice phenology and spring temperature show the existence of a very well defined trend that is not detectable in the series of winter NAO at time scales of a century or longer| This leads to the conclusion that winter NAO has still a weak| though significant| effect on the regime of spring temperature in the Baltic region and explains the most significant fluctuating components embedded in the cryophenological records. However it is argued that other climatic forcings| related to CO2-induced regional and global warming| acting at the end of the ice season| are able to induce pronounced trends in the regime of spring temperature and have an important impact on the cryosphere leading to the earlier occurrence of ice break-up observed in the last several decades. (C) 2002 Elsevier Science B.V. All rights reserved. 5889,2002,2,4,Trends and temperature sensitivity of moisture conditions in the conterminous United States,Observed (1895-1999) trends in climatic moisture conditions in the conterminous United States (US) characterized by (1) annual precipitation minus annual potential evapotranspiration (PMPE)| (2) annual surplus (water that eventually becomes streamflow)| and (3) annual deficit (the amount of water that must be supplied by irrigation to grow vegetation at an optimum rate) are examined. The sensitivity of moisture conditions across the conterminous US to increases in temperature also are examined. Results indicate that there have been statistically significant trends in PMPE| annual surplus| and annual deficit for some parts of the conterminous US. Most of the significant trends in PMPE have been increasing trends primarily in the eastern US. Annual surplus also has increased over the eastern US| whereas the magnitudes of annual deficit have decreased. For the conterminous US as a whole| there has been a statistically significant increase in PMPE and annual surplus; however| there is no significant trend in annual deficit. Results also indicate that PMPE and annual deficit in the warmest regions of the conterminous US are most sensitive to increases in temperature. The high sensitivity of PMPE and annual deficit in these regions to increases in temperature is related to the relation between temperature and the saturation vapor pressure of air. The increases in potential evapotranspiration for a given change in temperature are larger for high temperatures than for low temperatures. The regions with the highest sensitivity of annual surplus to increases in temperature are the humid regions of the country. In these regions| annual surplus is large and increased potential evapotranspiration| resulting from increased temperature| has a significant effect on reducing annual surplus. In the dry regions of the country| annual surplus is so low that increases in potential evapotranspiration only result in small decreases in annual surplus. 5743,2002,4,5,Tropical Pacific decadal variability and global warming,[1] An analysis of ocean surface temperature records show that low frequency changes of tropical Pacific temperature lead global surface air temperature changes by about 4 years. Anomalies of tropical Pacific surface temperature are in turn preceded by subsurface temperature anomalies in the southern tropical Pacific by approximately 7 years. The results suggest that much of the decade to decade variations in global air temperature may be attributed to tropical Pacific decadal variability. The results also suggest that subsurface temperature anomalies in the southern tropical Pacific can be used as a predictor for decadal variations of global surface air temperature. Since the southern tropical Pacific temperature shows a distinct cooling over the last 8 years| the possibility exists that the warming trend in global surface air temperature observed since the late 1970's may soon weaken. 5717,2002,2,4,Twentieth-century Scots pine growth variations in the central Scandinavian Mountains related to climate change,Climate-sensitive trees are valuable for reconstructing past climates| but they also can be used to assess the impacts of environmental change| such as global warming| on forest ecosystems. Growth variability and growth responses to climate of a Scots pine (Pinus sylvestris L.) tree-ring width chronology| from the treeline in the central Scandinavian Mountains| were studied throughout the 20th century. Summer temperatures| especially in July| were the most influential climate factor for tree growth. Correlation analyses in three 30-yr periods showed that growth responses to climate varied through time| being particularly low in 1931 to 1960. Nevertheless| tree growth around 1950 was the highest for 320 yr| implying optimal growth conditions. This growth increase appears to be a response to increased summer temperatures| a lengthening of the growing season| and a temporal change in the atmospheric circulation pattern. Despite a continuation of seemingly favorable growth conditions in the latter half of the 20th century| pine growth decreased after the 1950s. It appears that high-altitude pine experienced stress that surpassed the positive effect of improved growth season climate. Since pine growth decline coincided with an unprecedented strong and positive period of wintertime North Atlantic Oscillation (NAO)| a measure of strength of westerly winds bringing mild and moist air masses over Scandinavia| it is proposed that milder and wetter winters caused growth stress| and hence reduced growth| in high-altitude central Sweden. 5759,2002,2,4,Unexpected results of a pilot throughfall exclusion experiment on soil emissions of CO(2)| CH(4)| N(2)O| and NO in eastern Amazonia,The eastern Amazon Basin may become drier as a result of less regional recirculation of water in a largely deforested landscape and because of increased frequency and intensity of El Nino events induced by global warming. Drier conditions may affect several plant and soil microbial processes| including soil emissions of CO(2)| CH(4)| NO| and N(2)O. We report here unanticipated results of a pilot study that was initiated to test the feasibility of a larger-scale throughfall exclusion experiment. In particular| soil drying caused a switch from net consumption of atmospheric CH(4) by soils in the control plot to net CH(4) emission from soils in the experimentally dried plot. This result is surprising because production of CH(4) requires anaerobic microsites| which are uncommon in dry soil. A plausible explanation for increased CH(4) emissions in the dried plot is that dry soil conditions favor termite activity and increased coarse root mortality provides them with a substrate. Another surprise was|that both NO and N(2)O fluxes were elevated several years after initiation of the drying experiment. Apparently| a pulse of N availability caused by experimental drying persisted for at least 3 years. As expected| CO(2) emissions were lower in the dried plots| which is consistent with lower rates of root growth observed in root in-growth cores placed in the dried plots. More work is needed to test these explanations and to confirm these phenomena| but these results demonstrate that changes in climate could have unanticipated effects on biogeochemical processes in soils that we do not adequately understand. 5719,2002,3,2,Use of Chlorella vulgaris for CO2 mitigation in a photobioreactor,Carbon dioxide (CO2) is a colorless gas that exists at a concentration of approximately 330 ppm in the atmosphere and is released in great quantities when fossil fuels are burned. The current flux of carbon out of fossil fuels is about 600 times greater than that into fossil fuels. With increased concerns about global warming and greenhouse gas emissions| there have been several approaches proposed for managing the levels Of CO2 emitted into the atmosphere. One of the most understudied methods for CO2 Mitigation is the use of biological processes in engineered systems such as photobioreactors. This research project describes the effectiveness of Chlorella vulgaris| used in a photobioreactor with a very short gas residence time| in sequestering CO2 from an elevated CO2 airstream. We evaluated a flow-through photobioreactor's operational parameters| as well as the growth characteristics of the C. vulgaris inoculum when exposed to an airstream with over 1850 ppm CO2. When using dry weight| chlorophyll| and direct microscopic measurements| it was apparent that the photobioreactor's algal inoculum responded well to the elevated CO2 levels and there was no build-up of CO2 or carbonic acid in the photobioreactor. The photobioreactor| with a gas residence time of approximately 2 s| was able to remove up to 74% of the CO2 in the airstream to ambient levels. This corresponded to a 63.9-g/m(3)/h bulk removal for the experimental photobioreactor. Consequently| this photobioreactor shows that biological processes may have some promise for treating point source emissions Of CO2 and deserve further study. 5686,2002,4,4,Water and the environment: a natural resource or a limited luxury?,The risk of contamination of drinking water supplies with microbial pathogens is minimised by modern approaches to water management| but continues to be the major public health concern. Chemical contaminants usually pose little health risk except at very high levels| but debate continues over the potential adverse health effects of low-level| chronic exposure to compounds such as disinfection byproducts. Recreational water contact can be associated with adverse health outcomes either from microbial infections or exposure to cyanobacterial toxins. Environmental issues such as increasing salinity and global warming are likely to affect the sustainability of our current drinking water supplies and increase the threat of waterborne disease outbreaks. New technologies| use of alternative water sources| such as rainwater tanks| water reuse and restrictions will undoubtedly be part of the solution to our diminishing water resources| but have the potential to introduce new health threats. 5929,2002,2,4,Weakening of climatic constraints with global warming and its consequences for evergreen broad-leaved species,Meteorological stations located in the lower areas of southern Switzerland have recorded a period with distinct milder winter conditions since 1970 as compared with the first half of the 20th century. The twofold set of climatic parameters| the absolute values and frequency of minimum temperatures as well as the length of the growing season have shifted towards warmer conditions in the last thirty years. In this paper| consequences of the lengthened growing season to 11 months are discussed. The detected climatic change supposedly favours species with evergreen broad-leaved growth form. With the analysis of 170 resurveyed releves the hypothesis of whether the group of evergreen broad-leaved species have succeeded in profiting from this weakening of climatic constraints was verified. Conspicuous changes have been observed not only in terms of the abundance and frequency of indigenous evergreen broad-leaved species| but also with a number of exotic species sharing equal characteristics and having succeeded in colonizing forest areas and establishing stands in the shrub layer. It is suggested that in areas with a minimum temperature above -10 degreesC and sufficient water supply throughout the year| evergreen broad-leaved species become increasingly competitive as soon as the growing season (days without frost) lengthens to about 300-320 days. 5954,2002,3,3,Well joined well driven - How cars will be joined in the future,Beginning with a retrospect of the most significant innovations in automobile manufacturing| this contribution provides a survey of the currently used materials and joining methods| their merits and limits. The materials covered are high-strength steels| aluminum| magnesium| and plastic materials in structural and hang-on parts. Because of rising public concern on global warming| reduced fuel consumption of cars and lightweight design become more and more important. Cost effective light weight design leads to multimaterial design concepts| where the most suitable material for the specific application is chosen. Parallel to the trend to multimaterial design the requirements for joining technologies are increasing. Within the joining technologies there is a trend to combined processes like welding and adhesive bonding| or riveting and adhesive bonding. The potential for development of existing joining techniques and the demands on future methods are shown. 2888,2002,2,4,Year-class detection reveals climatic modulation of settlement strength in the European lobster| Homarus gammarus,Understanding the nature of recruitment relationships in the European lobster| Homarus gammarus| has been an intractable problem because of difficulties associated with quantification of its scarce planktonic larvae and early benthic phase. We attempt to address this problem by analyzing the age composition of a population off the northeast coast of England. Age-dependent in situ deposits of neurolipofuscin in the eyestalk are used as an age index. An approach is presented that accounts and (or) corrects for the two most important potential sources of error in age determinations by this technique| namely environmental temperature variation and unexplained individual variation. This yields| for the first time in very long-lived clawed lobsters| reproducible catch age structures with year-class resolution. The method should be generally applicable to crustaceans. Cross-correlation analysis shows that larval settlement strength in the European lobster is associated with local sea temperatures and onshore winds in a manner similar to that reported for other lobsters. These findings have important implications for stock assessment| particularly the use of traditional models dependent on size and steady state| yield forecasting| the effects of global climate change| arguments about spawner protection or restocking| and the spawner-recruit relationship. 2899,2002,2,4,Zonation of ground beetles (Coleoptera : Carabidae) and spiders (Araneida) in salt marshes at the North and the Baltic Sea and the impact of the predicted sea level increase,The ground beetles and spiders of two salt marshes at the German North and Baltic Sea coast were investigated by pitfall traps in 1997 and 1998. While the sites at the North Sea coast are tidal salt marshes| the salt marshes at the Baltic Sea are not influenced by tides. Pitfall traps were installed in a gradient from 20 to 150 cm above MHT (mean high tide: 157 cm + NN| NN: 500 cm above 0 at Amsterdam gauge) at the North Sea coast or NN at the Baltic Sea coast at six or seven sampling elevations| each with five replicates. Conductivity| water content| organic substance| frequency or duration of floodings| sand content and pH of the soil were determined. The flooding regime is the major factor controlling the zonation of invertebrates. Two and three invertebrate assemblages at the North and Baltic Sea| respectively| were distinguished. These corresponded well with the vegetational zones. The border between the two zones was at 60-80 cm above MHT at the North Sea. The three zones at the Baltic Sea extended between 20 and 30 cm| 40 to 80 cm and 100 to 150 cm above NN. The elevation of the mean abundance of species above MHT or NN was calculated. A tide simulation experiment resulted in a shifting population and in an increasing activity under a tidal regime as predicted for the global climate change conditions in 2050. From the actual elevation of the mean abundance| the habitat size of salt marsh species was calculated for a moderate and worse scenario of global climate change. Habitat reduction becomes highest for species of the lower salt marsh zone. Under worse conditions the gradiental length of habitat will only amount to a maximum of 20 m at the slopes of the dikes. 2727,2003,5,2,110000 years of Quaternary beetle diversity change,Our first aim was to document the effects of palaeotemperatures and vegetation changes on beetle assemblages| and secondly to determine the extent to which surrogacy analysis at the family taxonomic level reveals patterns evident from lower taxa analysis. The sedimentary sequence sampled on the experimental site of 'La Grande Pile' (Vosges| France) covers the whole of the last climatic cycle. Beetle fragments were extracted from 39 coring samples and identified to the lowest possible taxonomic level. A total of 3092 beetle specimens belonging to 394 taxa were identified| more than half to species level. Carabidae| Staphylinidae and Curculionidae families together represented 40% of the overall taxa richness. Beetle taxa richness and assemblage composition varied markedly over time. Average summer temperatures clearly play a major role in diversity patterns| as temperature was positively correlated with taxon richness. Nevertheless| the warmest and the coldest periods were not the richest and the poorest| respectively| and the most humid period did not correspond to maximum beetle richness. Beetle assemblages are likely to fluctuate in response to other factors such as plant diversity and vegetation structure. Steppe-like vegetation did not reduce species richness while dense| homogenous and closed forests did. Family patterns mirrored those observed at the lower taxa level. This makes the family level a convincing alternative to lower taxonomic level analyses by representing a faithful picture of changing beetle diversity over a long period of time. Finally| evolution of beetle diversity over the Quaternary represents a convincing model for evaluating the effect of close and wide past climate changes| and for assisting in management of present-day biodiversity as part of the current anthropogenic global climate change. 6094,2003,5,4,1200 years of fire impact on biogeochemistry as inferred from high resolution diatom analysis in a kettle lake from the Picea mariana-moss domain (Quebec| Canada),The consequences of fire on water chemistry are important considering that major changes in the frequency and intensity of forest fires are anticipated as a result of global warming. Due to the important differences in succesionnal vegetative trends after fire between mixed-wood and coniferous-dominated forests in Quebec (Canada)| we undertook a long-term paleoecological study of the impact of fires on the biogeochemistry of Lac a la Pessiere| a small lake located in a conifer-dominated boreal forest ecoregion ( Picea mariana-moss domain). The paleolimnological study was carried out using diatom assemblages (class: Bacillariophyceae) to reconstruct changes in environmental variables of limnological interest [pH| total phosphorus (TP)| total nitrogen (TN)| dissolved organic carbon (DOC) and| epilimnetic carbon dioxide (CO2)] potentially associated with fire over the last 1200 calendar years. Diatom composition and related reconstructed limnological variables were compared before and after fire events. No significant changes were systematically observed in lake chemistry associated with fire events. However| diatom-inferred epilimnetic CO2 showed a clear decreasing trend over the last similar to400 cal. yrs BP. The results suggest that fire-induced changes in lake chemistry are limited in catchments dominated by black spruce ( Picea mariana). We hypothesize that this fact result of excess moisture associated to the thick humus layer| which likely limits the mobilization of nutrients and major ions even during a fire event. 2781,2003,5,4,A 180|000-year pollen record from Owens Lake| CA: terrestrial vegetation change on orbital scales,Pollen from the upper 90 m of core OL-92 from Owens Lake is a climatically sensitive record of vegetation change that indicates shifts in the plant associations representing warm and cold desertscrub| pinyon-juniper woodland| and pine-fir forest during the past 180|000 years. These changes are synchronized with glacial-interglacial cycles. During glacial and stadial climates| juniper woodland expanded downslope and replaced warm desert shrubs while upper montane and subalpine forests in the and Inyo Mountains also expanded| and those in the Sierra Nevada were displaced by the ice cap and periglacial conditions. Conversely| during interglacial and interstadial climates| warm desert plants expanded their range in the lowlands| juniper and sagebrush retreated upslope| and montane and subalpine forests expanded in the Sierra Nevada. The reconstructed vegetation history demonstrates a regional climatic response| and the congruence of the pollen sequence with marine and ice cap oxygen isotope stratigraphies suggests a link between regional vegetation and global climate change at orbital scales. (C) 2003 Elsevier Science (USA). All rights reserved. 5965,2003,2,4,A change in the freshwater balance of the Atlantic Ocean over the past four decades,The oceans are a global reservoir and redistribution agent for several important constituents of the Earth's climate system| among them heat| fresh water and carbon dioxide. Whereas these constituents are actively exchanged with the atmosphere| salt is a component that is approximately conserved in the ocean. The distribution of salinity in the ocean is widely measured| and can therefore be used to diagnose rates of surface freshwater fluxes(1)| freshwater transport(2) and local ocean mixing(3) - important components of climate dynamics. Here we present a comparison of salinities on a long transect (50degrees S to 60degrees N) through the western basins of the Atlantic Ocean between the 1950s and the 1990s. We find systematic freshening at both poleward ends contrasted with large increases of salinity pervading the upper water column at low latitudes. Our results extend a growing body of evidence indicating that shifts in the oceanic distribution of fresh and saline waters are occurring worldwide in ways that suggest links to global warming and possible changes in the hydrologic cycle of the Earth. 6072,2003,3,3,A combined study of preparation and characterization of carbon molecular sieves (CMS) for carbon dioxide adsorption from coals of different origin,Removal of carbon dioxide from the atmosphere as well as waste gas streams from industrial and power stations has become the present day's world-wide attraction for many reasons| the most important being the trapping of heat from the sun by CO2 and hence disruption of global warming effect. Activated carbon and CMS samples were prepared from coal samples of different origin. The effects of the various process parameters to prepare CMS from various coals were studied. Pre-oxidation of the coal| activation using CO2 and pore narrowing through coke deposition by benzene cracking were the major process parameters used to prepare the CMS in this work. The CO2 adsorption capacity of the samples was studied using gravimetric as well as volumetric methods. The adsorption capacity Of CO2 on the CMS samples prepared was found to be 1.6 mmol/g of the adsorbent with an uptake ratio at equilibrium adsorption for CO2/CH4| >> 20. The morphology of the pore structure of the samples was studied using the Scanning Electron Microscope (SEM). The N-2 adsorption on the samples at liquid N-2 temperature was found to be very poor and hence surface area measurement was done using CO2 adsorption data. The BET surface area thus calculated was found to be 20% less than the DA surface area calculated. 6130,2003,2,3,A comparison of climate change simulations produced by two GFDL coupled climate models,The transient responses of two versions of the Geophysical Fluid Dynamics Laboratory (GFDL) coupled climate model to a climate change forcing scenario are examined. The same computer codes were used to construct the atmosphere| ocean| sea ice and land surface components of the two models| and they employ the same types of sub-grid-scale parameterization schemes. The two model versions differ primarily| but not solely| in their spatial resolution. Comparisons are made of results from six coarse-resolution R 15 climate change experiments and three medium-resolution R30 experiments in which levels of greenhouse gases (GHGs) and sulfate aerosols are specified to change over time. The two model versions yield similar global mean surface air temperature responses until the second half of the 21st century| after which the R15 model exhibits a somewhat larger response. Polar amplification of the Northern Hemisphere's warming signal is more pronounced in the R15 model| in part due to the R15's cooler control climate| which allows for larger snow and ice albedo positive feedbacks. Both models project a substantial weakening of the North Atlantic overturning circulation and a large reduction in the volume of Arctic sea ice to occur in the 21st century. Relative to their respective control integrations| there is a greater reduction of Arctic sea ice in the R15 experiments than in the R30 simulations as the climate system warms. The globally averaged annual mean precipitation rate is simulated to increase over time| with both model versions projecting an increase of about 8% to occur by the decade of the 2080s. While the global mean precipitation response is quite similar in the two models| regional differences exist| with the R30 model displaying larger increases in equatorial regions. (C) 2003 Elsevier Science B.V. All rights reserved. 6227,2003,3,4,A critical assessment of renewable energy usage in the USA,The displacement of non-renewable fossil fuels by renewable energy resources has occurred at a low rate in the USA. But a large number of drivers is expected to cause significant expansion of the US renewable energy industry in the near future. Included among the extrinsic drivers| or those that are not directly related to renewable energy resources| are reductions in natural gas and crude oil supplies and the OPEC Effect. An assessment of petroleum crude oil and natural gas consumption and reserves supports the position that supply problems and significant cost increases will start to occur in the first and second quarters of this century. Among the intrinsic drivers| or those that are directly related to renewable energy resources| are global warming and specific government incentives and mandates such as Renewable Portfolio and Fuel Standards that require the commercial use of renewable energy resources. The increasing US dependence on imported crude oil and environmental and political issues will drive the growth of the renewable energy industry and result in the gradual phase-out of what can be called the Fossil Fuel Era. By the end of this century| the dominant commercial energy mix in the USA is projected to include major contributions by renewable energy resources to help satisfy energy and fuel demands. Practical solutions to the problems of disposing of spent nuclear fuels and the development of clean coal applications will enable these energy resources to afford major contributions also. (C) 2002 Elsevier Science Ltd. All rights reserved. 2753,2003,4,4,A GIS-based Spatial Pattern Analysis Model for eco-region mapping and characterization,Growing concerns about global climate change| biodiversity maintenance| natural resources conservation| and long-term ecosystem sustainability have been responsible for the transformation of traditional single resource management approaches into integrated ecosystem management models. Eco-regions are large ecosystems of regional extent that contain smaller ecosystems of similar response potential and resource production capabilities. They can be used as a geographical framework for organizing and reporting resource information| setting bioecological recovery criteria| extrapolating site-level management| and monitoring global change. The objective of this research is to develop a quantitative| multivariate regionalization model that is capable of delineating eco-regions at multiple levels from remotely sensed information and other environmental and natural resources spatial data. The Spatial Pattern Analysis Model developed in this study uses a region-growing algorithm to generate spatially contiguous regions from primitive polygonal land units. The algorithm merges the most similar pair of neighbouring units at each iteration| based on satisfying certain similarity criteria until all units are grouped into one. This model was utilized to develop an eco-region map of Nebraska with three hierarchical levels. In the mapping process| the STATSGO data set was used to build the primitive map units. Environmental parameters included in the model were multi-temporal AVHRR data| soil rooting depth| organic matter content| available water capacity| and long-term annual averages of water balance and growing degree day totals. Development of the model provides a new and useful approach to eco-region mapping for resource managers and researchers. The method is automated and efficient| reduces the judgement biases and uncertainty of manual analyses| and can be replicated for other regions or for the regionalization of other themes. 6198,2003,3,4,A life-cycle comparison of several auxiliary blowing agents used for the manufacture of rigid polyurethane foam,In a commitment to zero ozone depletion| the United Nations and the U.S. Environmental Protection Agency (EPA) have called for the phase-out of the manufacture and import of hydrochlorofluorocarbons (HCFCs)| used as auxiliary blowing agents (ABAs) in the manufacture of polyurethane foams. As a result| more environmentally benign alternative ABAs are being sought by the foam-blowing industry. This study examined the life cycle of HCFC-22| hydrofluorocarbon-134a (HFC-134a)| and cyclopentane| which are currently used or considered as potential alternative ABAs in the manufacture of rigid polyurethane foams that serve as insulation in a model North American refrigerator. The raw material extraction/refining| manufacturing| use| and disposal stages of the life cycle of each ABA were considered| and their resulting relative impacts on ozone depletion and global warming were compared. The manufacturing| use| and disposal stages were determined to affect ozone depletion and global warming to the largest extent| emphasizing the need for a greater focus on pollution prevention opportunities in these stages. The HFC-134a life cycle yields no impact on ozone depletion and a significantly decreased global warming impact compared with its predecessor| HCFC-22| and a tradeoff of slightly higher global warming impact and fewer added safety concerns compared with its more flammable counterpart| cyclopentane. 2735,2003,3,4,A MERGE model with endogenous technological progress,We have developed a new version of the MERGE model| called MERGE-ETL| to analyse the dynamics of endogenous technological learning (ETL) in the energy system. This paper describes the basic formulation of MERGE-ETL| the solving techniques used for this model and some first numerical results in the context of policies designed to mitigate global climate changes. 6205,2003,2,4,A model for regional-scale estimation of temporal and spatial variability of active layer thickness and mean annual ground temperatures,High-latitude ecosystems where the mean annual ground surface temperature is around or below 0 degreesC are highly sensitive to global warming. This is largely because these regions contain vast areas of permafrost| which begins to thaw when the mean annual temperature rises above freezing. The Geophysical Institute Permafrost Lab has developed a new interactive geographical information systems (GIS) model to estimate the long-term response of permafrost to changes in climate. An analytical approach is used for calculating both active layer thickness (ALT) and mean annual ground temperatures (MAGTs). When applied to long-term (decadal or longer time scale) averages| this approach shows an accuracy of +/-0.2-0.4degreesC for MAGTs and +/-0.1-0.3 in for ALT calculations. The relative errors do not exceed 32% for ALT calculations| but typically they are between 10 and 25%. A spatial statistical analysis of the data from 32 sites in Siberia indicated a confidence level of 75% to have a deviation between measured and calculated MAGTs of 0.2-0.4degreesC. A detailed analysis has been performed for two regional transects in Alaska and eastern Siberia that has validated the use of the model. The results obtained from this analysis show that a more economical (in terms of computational time) analytical approach could be successfully used instead of a full-scale numerical model in the regional and global scale analysis of permafrost spatial and temporal dynamics. This project has been a successful contribution to the Arctic Climate Impact Assessment project. Copyright (C) 2003 John Wiley Sons| Ltd. 6040,2003,3,3,A new generalized carbon exergy tax: An effective rule to control global warming,An instrument for promoting CO(2) emission reductions| taking the Kyoto Protocol goal into account| could be the assignment to energy conversion plants of a monetary charge linked to their specific emission intensity| usually called carbon tax. There are two main problems closely connected with this approach: the estimation of the charge (that must be related to the "external" cost associated with CO(2) emission) and the choice of the strategy to determine the amount of the imposed charge. In this paper an analytical procedure proposed by the authors and called carbon exergy tax (CET) for the evaluation Of CO(2) emission externalities is presented. It is based on the thermoeconomic analysis of energy systems| which allows second law losses to be quantified in monetary terms: the resulting cost represents the taxation that is to be applied to the energy system under examination| calculated without any arbitrary assumption. Since the complete procedure of the CET evaluation is too complex to become a feasible instrument of energy policy| hereby| after applying the procedure to some conventional and advanced power plants| gas| oil| and coal-fueled| a new generalized approach| based on the results of the complete CET procedure| is proposed. The generalized CET evaluation requires much less information about the energy system and thus a simple and effective energy policy rule to manage global warming is obtained and available. 6305,2003,5,4,A new scenario for the Domerian - Toarcian transition,In contrast to the majority of recently published hypotheses| we believe that the main trigger for early Toarcian anoxia is neither increased primary productivity during the Tenuicostatum and Falciferum Zones nor sudden methane hydrate degassing close to the transition between these two zones. In our opinion| this peculiar pateoceanographic episode is linked to a major| though short-lived| regression at the end of Upper Domerian. Sea-level fall resulted from sudden cooling due to increased volcanic activity. This generated global thermal insulation and subsequent glaciation. The regression is responsible for a major hiatus over NW-European epicontinental seas and is later followed by the well-known Lower Toarcian transgression. The interval corresponding to this hiatus allowed vegetation to colonise vast newly emerged surfaces. The leaching and drowning of the accumulated organo-humic matter then triggered the anoxic cycle at the transgressive maximum| concomitant with a global warming. 6295,2003,4,4,A reassessment of carbon content in wood: variation within and between 41 North American species,At present| 50% (w/w) carbon is widely promulgated as a generic value for wood; however| the literature yields few data and indicates that very little research has actually been done. C contents in heartwood of forty-one softwood and hardwood species were determined. C in kiln-dried hardwood species ranged from 46.27% to 49.97% (w/w)| in conifers from 47.21% to 55.2%. The higher C in conifers agrees with their higher lignin content (similar to 30%| versus similar to 20% for hardwoods). Wood-meal samples drilled from discrete early wood and late wood zones of seven of the forty-one species were also investigated. C contents of early woods were invariably higher than those in corresponding late woods| again in agreement with early wood having higher lignin content. Further investigation was made into freshly harvested wood of some species to determine how much volatile C is present| comparing oven-dried wood meal with wood meal dried at ambient temperature over a desiccant. C contents of oven-dried woods were significantly lower| indicating that all past data on C content in oven- or kiln-dried woods may be inaccurate in relation to the true C content of forests. We conclude that C content varies substantially among species as well as within individual trees. Clearly| a 50% generic value is an oversimplification of limited application in relation to global warming and the concept of "carbon credits". (C) 2003 Elsevier Ltd. All rights reserved. 6121,2003,2,4,A review of the possible impacts of long-term oceanic and climate changes and fishing mortality on recruitment of anguillid eels of the Northern Hemisphere,Possible causes of declines in recruitment of European| American and Japanese eels to continental waters are reviewed. Negative correlations between the Den Oever glass eel recruitment index (DOI) and the North Atlantic Oscillation Index since 1938 are discussed| together with older anecdotal evidence. Correlations are established between the DOI and sea surface temperature anomalies at 100-250 in between 1952 and 1995 in the Sargasso Sea/Sub-Tropical Gyre (STG) spawning area. It is hypothesised that| associated with global warming trends| STG warming inhibits spring thermocline mixing and nutrient circulation| with negative impacts on productivity and hence food for leptocephalus larvae. Concurrent gyre spin-up also affects major currents and slowing of oceanic migration has probably enhanced starvation and predation losses. Local factors| such as unfavourable wind-driven currents| can also affect recruitment of glass eels on continental shelves. In contrast| evidence is discussed that indicates fishing mortality and continental climate change appear to have had lesser impacts. Similar starvation-advection explanations for declines in Japanese eel recruitment are proposed. Predictions for the future are made and multidisciplinary and integrated monitoring and research are recommended for managing eel stocks and fisheries. (C) 2003 Elsevier Science B.V. All rights reserved. 6211,2003,2,4,A review of the risks of sudden global cooling and its effects on agriculture,Global warming has received much attention| but evidence from the past shows that sudden global cooling has occurred with severe failures of agriculture. Extrapolating from dendrochronological evidence| one can predict the following: Approximately once per century there will be a drop of about 0.5-1 degreesC in mean temperature worldwide. In some of these cases| perhaps once every 200 or 300 years this might endanger agricultural production globally. About once per millenium there will be periods of 5-20 years where the temperature is seriously below normal. The last major one year temperature drop was 1816| the year without a summer| probably caused by the cooling effect of the eruption of the volcano Tambora| Indonesia. The last decade-long cooling event was A.D. 536-545 where dust veil| cold| famine| and plague was recorded in Byzantium and China. Very large volcanic eruptions or a comet/asteroid impact have been suggested as cause. Nuclear winter after large-scale nuclear war is a well-known scenario| but climate instabilities may also be caused by changes in the sun| Milankovitch cycles| changes in ocean currents| volcanoes| asteroid impacts| dusting from comets passing close| methane released from its hydrate| and pollution| The risks associated with sudden global cooling are rather smaller than the risks of global warming| but they are real. A dangerous sudden cooling event will happen sooner or later. Ability to change to cold-resistant crops rapidly in large parts of the world may be necessary to avoid major famines. With some important exceptions| fundamental research in abrupt climate change is in place| but agricultural or economic research on volcanic/comet-dusting/nuclear winters and their mitigation is lacking. (C) 2003 Elsevier Science B.V. All rights reserved. 6194,2003,4,4,A seasonal model to simulate influenza oscillation in Tokyo,The purpose of our study was to establish a seasonal model to simulate the oscillation of the number of influenza cases with weather conditions and calendar months in Tokyo| Japan| during the winter season. Surveillance data for influenza in Tokyo was retrieved from the Infectious Agents Surveillance Report| published by the National Institute of Infectious Diseases in Japan. We obtained data for 86 parameters of weather conditions from the Meteorological Agency. The best-fit model was built by multiple regression with stepwise analysis. The reported number of patients with influenza per week was significantly increased with fewer days of maximum temperature greater than or equal to10 degreesC per week (T10) and more days of relative humidity <60% per week (S60)| adjusted by calendar month| average temperature| and vapor pressure. Annual oscillation of the number of reported influenza cases at the start| peak| and end weeks almost exactly matched the model| although peak levels for each oscillation did not always match. However| this model showed that 81% of the variation among the observed number of influenza cases was explained by a linear relationship with the seasonal parameters utilized. The validity of this model applied to data from 1999 to 2002| showing a 75% correlation. Using this model| if the number of days with both T10 and S60 increased by one per week| the number of influenza cases was simulated to decrease by approximately half. These results suggest that most of the oscillation in the number of influenza cases may be explained using a seasonal model that can simulate the impact of global warming. 6196,2003,2,3,A simple global carbon and energy coupled cycle model for global warming simulation: sensitivity to the light saturation effect,A simple Earth system model| the Four-Spheres Cycle of Energy and Mass (4-SCEM) model| has been developed to simulate global warming due to anthropogenic CO2 emission. The model consists of the Atmosphere-Earth Heat Cycle (AEHC) model| the Four Spheres Carbon Cycle (4-SCC) model| and their feedback processes. The AEHC model is a one-dimensional radiative convective model| which includes the greenhouse effect of CO2 and H2O| and one cloud layer. The 4-SCC model is a box-type carbon cycle model| which includes biospheric CO2 fertilization| vegetation area variation| the vegetation light saturation effect and the HILDA oceanic carbon cycle model. The feedback processes between carbon cycle and climate considered in the model are temperature dependencies of water vapor content| soil decomposition and ocean surface chemistry. The future status of the global carbon cycle and climate was simulated up to the year 2100 based on the "business as usual" (IS92a) emission scenario| followed by a linear decline in emissions to zero in the year 2200. The atmospheric CO2 concentration reaches 645 ppmv in 2100 and a peak of 760 ppmv approximately in the year 2170| and becomes a steady state with 600 ppmv. The projected CO2 concentration was lower than those of the past carbon cycle studies| because we included the light saturation effect of vegetation. The sensitivity analysis showed that uncertainties derived from the light saturation effect of vegetation and land use CO2 emissions were the primary cause of uncertainties in projecting future CO2 concentrations. The climate feedback effects showed rather small sensitivities compared with the impacts of those two effects. Satellite-based net primary production trends analyses can somewhat decrease the uncertainty in quantifying CO2 emissions due to land use changes. On the other hand| as the estimated parameter in vegetation light saturation was poorly constrained| we have to quantify and constrain the effect more accurately. 6051,2003,2,4,A stochastic sediment delivery model for a steep Mediterranean landscape,[1] It is a truism in geomorphology that climatic events operate on a landscape to drive sediment transport processes| yet few investigations have formally linked climate and terrain characteristics with geomorphological processes. In this study| we incorporate sediment transport equations derived from fieldwork into a computer model that predicts the delivery of sediment from hillslopes in a steep Mediterranean landscape near Santa Barbara| California. The sediment transport equations are driven by rainstorms and fires that are stochastically generated from probability distributions. The model is used to compare the rates and processes of sediment delivery under two vegetation types: coastal sage scrub and grasslands. Conversion of vegetation from sage to exotic grasses is a common land management strategy in the region and may also be engendered by regional climate change due to global warming. Results from the model suggest that (1) approximately 40% more sediment is delivered from grasslands (98 t km(-2) yr(-1)) than the sage scrub (71 t km(-2) yr(-1)) and (2) chronic soil creep processes dominate under grasslands whereas catastrophic processes dominate under coastal sage scrub. Results from the model also suggest that changes in the spatial distribution of vegetation arising from climate change will have a greater effect on sediment delivery than changes in the magnitude and frequency of meteorological events. 6052,2003,2,4,A super-large landslide in Tibet in 2000: background| occurrence| disaster| and origin,On April 9| 2000| a super-large landslide (3 x 10(8) m(3)) occurred along Zhamu Creek| southeast Tibet. As a result| a landslide dam formed and the Yigong River was blocked. A channelized diversion was constructed for prevention of overtopping. Two months later on June 10| a catastrophic flood resulting from the failure of the landslide dam caused a serious loss of property. This is the second of landslide occasion dam formation and flooding occurrence at the same site since 1900. In this paper we introduce the background and occurrence of the landslide| report the dam failure and overflow process| and finally discuss the origin of the landslide and of the flood in comparison with statistical characteristics of previous case histories worldwide. Many large and small landslides will continue to occur because of the distinctive physiographic| geological and climatic conditions in this region. What we can do is perhaps only to predict and avoid them. With predicted global warming| water availability has become more and more important for landslide occurrence. (C) 2003 Elsevier Science B.V. All rights reserved. 2768,2003,2,4,A temperate| tidal lake-wetland complex - 1. Water balance and ecological implications,A water-balance model was developed for a tidal lake-wetland complex to: (1) determine the relative contribution of hydrological flows through the lake-wetland complex; (2) determine the tidal and non-tidal hydraulic residence times of two lakes in the lake-wetland complex; and (3) estimate the potential importance of groundwater inputs to the lake-wetland complex. All surface hydrological inputs to the system were either measured or estimated over 1 year. Daily evaporation from the water bodies was also estimated. Discharge at the outflow of the lake-wetland complex was monitored to calculate the net daily outflow. A correction procedure was used to remove the error resulting from aliasing of the daily calculation period and the tidal period. The difference between the measured net outflow and that calculated by the water-balance model indicated that a large amount of net discharge from the lake-wetland complex may have been a result of previously unrecognised groundwater inputs to the system. The non-tidal hydraulic residence times of the two lakes differed markedly as did the relative importance of tidal inflows. The influence of variation in tidal and non-tidal hydraulic residence time on limnological processes is discussed| particularly with respect to impacts of global climate change on tidal lake ecosystems. 2764,2003,2,4,A temperate| tidal lake-wetland complex - 2. Water quality and implications for zooplankton community structure,Lakes Waihola and Waipori are shallow| coastal| tidal lakes that experience wind-induced sediment resuspension| saline intrusions| and high inputs of nutrients. To determine the influence of externally-driven| physical factors on spatial and temporal patterns of water quality in the two lakes| meteorological| hydrological| and water quality data were collected over 1 year. Multivariate analyses indicated that wind energy was driving the main water quality gradient in the lakes| which was primarily related to wind-induced resuspension of lake sediments. The major| seasonally regulated| nontidal freshwater inflow was important in determining nutrient and salinity gradients in the lakes. The main nutrient inputs to the system were identified as the regulated| non-tidal inflow (the upper Waipori River) and the tidal inflow (lower Waipori River). The impact of water quality gradients on zooplankton community structure in the lakes was assessed by canonical multivariate methods. Salinity gradients| caused by seasonal saltwater intrusions| were strongly related to zooplankton community structure in the lakes. Nutrient gradients (indicative of trophic state) were also related to zooplankton community structure. Although wind-induced sediment resuspension had the largest impact on water quality in the lakes| it had little impact on the zooplankton community structure in either lake. The relationships between water quality and zooplankton community structure were confounded in Lake Waipori because of its very short hydraulic residence time (annual mean = 1.9 days). Zooplankton community structure was resilient to short-term changes in suspended particulate matter concentrations but not to seasonal changes in salinity. The results of this study support others which have shown impacts of even relatively small variations in salinity on the structure of zooplankton communities. This highlights the vulnerability of zooplankton communities in coastal lakes and wetlands to increasing salinity resulting from sea level rise and global climate change. 6056,2003,4,4,Absolute photo-absorption cross sections and electronic state spectroscopy of selected fluorinated hydrocarbons relevant to the plasma processing industry,Photo-absorption cross sections have been measured for methyl iodide| CF(3)I (310 nm > lambda > 110 nm) and dichlorodifluoromethane| CCl(2)F(2) (225 nm > lambda > 110 nm) using synchrotron radiation. Electron energy loss spectroscopy was also used to probe the electronic and vibronic excitation of CF(3)I. Electronic states have been assigned to each of the observed absorption bands incorporating both valence and Rydberg transitions. The measured VUV cross sections are used to derive the photolysis rates in the terrestrial atmosphere and hence determine the potential importance of each gas in global warming and ozone depletion. (C) 2003 Elsevier Science Ltd. All rights reserved. 6086,2003,2,4,Acidic deposition| nutrient leaching and forest growth,Studies in Germany and confirmed in North America established that the forest decline that developed in the late 1970' s and 80' s resulted from a deficiency in one or more of the nutrient cations: Ca2+| Mg2+| and K+. These nutrients are essential to the structure of the foliage| to photosynthesis and to the growth of the trees. The reactions and mechanisms involved in the entry of nutrients to the soil| their storage| and rate of transfer to the soil solution| and through it| to the. ne roots and to the leaves at the top of the tree are reviewed. The continuing material balance studies carried out on a watershed at the Hubbard Brook Experimental Forest in New Hampshire allow a unique analysis of the changes caused in these nutrient transfers by acid rain. The nutrient cations are stored in the soil by adsorption on negatively charged clay| and the presence of an acid is required for their release to the soil solution. In pre-industrial times this acid was H2CO3| which was subsequently displaced from the soil solution by H2SO4 and HNO3| as a result of acid deposition. The effect of the increased concentration of the negatively charged SO42- and NO3- anions seeping through the soil| compared with that of the HCO3- that had been previously present| resulted in a substantially increased rate of transfer of an equivalent of Ca2+ and other positively charged nutrient cations from the soil to the soil solution. The increased concentration of Ca2+ in the soil solution resulted in both an initial increase in the rate of biomass growth and in a simultaneous increase in the rate of Ca2+ loss in the effluent soil solution from the watershed. It was found that this increased rate of removal of Ca2+ from the watershed soil had become greater than its rate of input to the soil from weathering and from dust and rain. As a result| the large Ca2+ inventory that had built up in the soil as a result of the reduced leaching in the years prior to the entry of acid rain| that started in about the 1880's| was eventually depleted in the hardwood forest at Hubbard Brook in the 1980's| about 100 years later. With insufficient Ca2+ available for its continuing transfer| net biomass growth on the watershed stopped. This resulted from the rate of tree mortality becoming equal to that of the small incremental growth of a few trees on the watershed. The future growth of forests is at risk from the long-term effects of acid deposition. The fundamental nature of the reactions involved indicates that similar growth anomalies are occurring in other forests impacted by acid rain. These changes from normal biomass growth can affect the amount of CO2 stored in the biomass| of importance to our understanding of Global Warming. 6178,2003,2,4,Adaptation measures for climate change and the urban heat island in Japan's built environment,Climate change scenarios are discussed for Japan with clear implications drawn for the built environment in terms of increased temperatures of 4-5degreesC| rising sea levels and subterranean water tables. Research on the impacts and adaptation measures for global warming in Japan is reviewed. One of the most significant impacts of climate change in Japan will exacerbate the existing heat island phenomenon in cities by absorbing increased solar radiation. This will lead to further increases in temperatures in an urban microclimate with negative implications for energy and water consumption| human health and discomfort| and local ecosystems. The current urban heat island phenomenon and its impacts are described. The relationships between climate change and urban heat island impacts are discussed. Potential adaptation measures to those impacts are also discussed and proposed. 6269,2003,2,4,Aerial photographic interpretation of vegetation changes on the Bogong High Plains| Victoria| between 1936 and 1980,The vegetation of two areas on the Bogong High Plains in 1936 was compared with that in 1980 by using a point sampling technique on aerial photographs. Between 1936 and 1980| the cover of closed heathland| wetland and trees (Eucalyptus pauciflora) increased but the cover of grassland decreased. No change was detected overall in the cover of open heathland. The increase in closed heathland was not due to direct conversion of grassland areas. Most change was from grassland to open heathland and from open heathland to closed heathland vegetation. The increase in wetland vegetation may have been a response to the reduction in grazing pressure since the 1930s. The greater cover of trees in 1980 was due to expansion of existing patches rather than the establishment of new patches. This may have been attributable in part to regeneration following bushfires in 1926 and 1939. The possible role of higher mean temperatures associated with global warming in the increased tree and shrub cover is worthy of further investigation. 2731,2003,5,4,Age interpretation of the Wonderkrater spring sediments and vegetation change in the Savanna Biome| Limpopo province| South Africa,Spring accumulations are valuable and rare sources for Quaternary pollen analysis and palaeoenvironmental research in South Africa. It is important to optimize their dating| which is sometimes complicated by root contamination. Thirteen new radiocarbon dates are presented from one of the most significant spring pollen sequences on which South African vegetation history is based| namely| from Wonderkrater in the Savanna Biome. Some anomalous measurements were recorded but a new chronology is proposed by excluding samples that were possibly contaminated by younger or older materials. The dating places the pollen-based vegetation history more firmly in a framework of regional and global climate change during the Late Quaternary| thereby making the information more suitable for comparison with other sequences and as vegetation data in global-change modelling. 6090,2003,3,3,Allocating the responsibility of CO2 over-emissions from the perspectives of benefit principle and ecological deficit,Responsible emissions of anthropogenic carbon dioxide (CO2) are currently estimated according to the principle of territorial responsibility; that is| individual countries are only responsible for the anthropogenic CO2 emissions within their own political boundaries. In the context of globalization of world economies| such an accounting principle would easily result in carbon leakage| thus undermining the effects of global warming combat. From the perspectives of benefit principle and ecological deficit| this paper develops a framework to estimate the amount of responsible anthropogenic CO2 over-emissions| which serves as a basis for calculating the amount of anthropogenic CO2 reduction that a defined country is responsible for. The benefit principle assigns the responsibility of pollutant emissions to the driving forces behind the activities that emit pollutants rather than to direct emitters. The perspective of ecological deficit proposes that a country should take the responsibility for reducing pollutant emissions when it runs the deficits of assimilation| that is| its responsible emissions exceeding its capacity of assimilation. The proposed framework is demonstrated using the data of Taiwan in 1996| and discussions on improving and extending the framework in future research are provided. (C) 2003 Elsevier B.V. All rights reserved. 6219,2003,2,4,Altitudinal treelines of the southern Andes near 40 degrees S-1,In the southern Andes near 40degreesS| altitudinal treelines are dominated by Nothofagus pumilio| a broadleaf deciduous angiosperm in the beech family (Fagaceae). Treeline elevations| ranging from 1100 to 1500 in a.s.l.| are influenced by regional climate and volcanism. At the local scale| disturbance influences treeline elevation| ecotone length| and vegetation productivity. Decadal and interannual variation in climate related to El Nino-Southern Oscillation (ENSO) significantly affected radial growth of krummholz trees and seedling demography: however| climate-treeline relations were complex. Radial growth of krummholz trees and seedling demography responded differently to climate variation. These relations differed between climate regions and were unstable through time. We conclude that inter-annual variations in climate| such as those associated with ENSO| will be critical for successful reproduction and growth of Nothofagus pumilio at treeline in the Andes under the influence of global warming. 2772,2003,2,4,An accumulation map for the Greenland dry-snow facies derived from spaceborne radar,[1] An important component of ice sheet mass balance calculations is the snow accumulation rate| traditionally determined across the ice sheet from interpolated ice core data. We derive an accumulation rate map within the Greenland dry-snow facies| using C-band radar backscatter and the mean annual temperature. Values for the backscatter were obtained from the ERS-1 synthetic aperture radar mosaic acquired during September November 1992. An empirical equation| based on elevation and latitude| is used to determine the mean annual temperature. We examine the influence of accumulation rate| and mean annual temperature on C-band (5.3 GHz) radar backscatter| using a forward model| which incorporates snow metamorphosis and radar backscatter components. Our model is run over a range of accumulation and temperature conditions| consistent with the Greenland dry-snow facies. On the basis of our modeled results| a look-up table is generated| which uniquely maps the measured radar backscatter and mean annual temperature to accumulation rate. Our results compare favorably (15.4% average difference) with 124 in situ accumulation rate measurements falling within our study area. We attribute some of the differences to ( 1) unreliable in situ data points| which were based on a single year's accumulation and ( 2) a systematic underestimate of accumulation rate by our forward model in the low-accumulation regions associated with the northern portion of our map. With questionable data points and those above 77 degreesN removed| the average differences were less than 10.3%| as determined from 73 ice cores. 6210,2003,5,4,An alternative age model for the Paleocene-Eocene thermal maximum using extraterrestrial He-3,A continuous age model for the brief climate excursion at the Paleocene-Eocene boundary has been constructed by assuming a constant flux of extraterrestrial He-3 (He-3(ET)) to the seafloor. (HeET)-He-3 measurements from ODP Site 690 provide quantitative evidence for the rapid onset ( < few kyr) and short duration ( < 120 kyr) of global warming and of the associated disturbance to the Earth's surficial carbon budget at this time. These observations support astronomically calibrated age models indicating extremely rapid release of isotopically light carbon| possibly from seafloor methane hydrate| as' the proximal cause of the event. However| the He-3(ET) technique indicates a previously unrecognized and extreme increase in sedimentation rate coincident with the return of climate proxies to pre-event values. The He-3(ET)-based age model thus suggests a far more rapid recovery from the climatic perturbation than previously proposed or predicted on the basis of the modern carbon cycle| and so may indicate additional or accelerated mechanisms of carbon removal from the ocean-atmosphere system during this period. He-3(ET) was also measured at ODP Site 1051 to test the validity of the Site 690 chronology. Comparison of these data sets seems to require removal of several tens of kyr of sediment within the climatic excursion at Site 1051| an observation consistent with sediment structures and previous age modeling efforts. The Site 1051 age model shows a similar to30 kyr period in which climate proxies return toward pre-event values| after which they remain invariant for similar to80 kyr. If this rise represents the recovery interval identified at Site 690| then the 3 HeET-based age models of the two sites are in good agreement. However| alternative interpretations are possible| and work on less disrupted sites is required to evaluate the reliability of the proposed new chronology of the climate excursion. Regardless of these details| this work shows that the 3HeET technique can provide useful independent evidence for the development and testing of astronomically calibrated age models. (C) 2003 Elsevier Science B.V. All rights reserved. 2713,2003,3,3,An equity first| risk-based framework for managing global climate change,This paper presents an alternative framework to the approach currently embodied in the Kyoto Protocol for managing global climate change post-2012. The framework has two key provisions. The first is that each person in the world would be 'allowed' an equal amount of greenhouse gas (GHG) emissions. This is labeled the equity-first provision. The second provision focuses on incorporating risk concepts into the setting of GHG emission reductions. It is proposed that the global climate be managed as to avoid three categories of risks: (I) Substantial regional economic| political| and/or biological impacts; (II) Severe global economic| political| and/or biological impacts; and (III) Extinction of humans. Acceptable risk thresholds are suggested to be one-in-a-million| one-in-one-hundred-million| and one-in-ten-billion| respectively. This equity-first| risk-based framework overcomes many criticisms of the current Kyoto Protocol: it explicitly involves all countries on earth; it avoids several administrative issues that are anticipated to plague a global carbon emissions trading market; and it avoids several contentious issues associated with pegging carbon emission reductions to 1990 levels. Because the framework is risk-based and emissions are tied to population and not historic emission levels| the basic framework would not have to be frequently renegotiated| as will be needed for the Kyoto-style approach to take the world past that agreement's 2012 endpoint. (C) 2003 Elsevier Ltd. All rights reserved. 2704,2003,2,4,Analysis of the duration| seasonal timing| and location of North Atlantic tropical cyclones: 1950-2002,Many scientists have suggested that a warmer world with elevated atmospheric moisture levels could increase the frequency| intensity| or duration of future tropical cyclones or alter their mean locations. While others have examined historical patterns in tropical cyclone frequency and intensity| and generally found no trends in recent decades| we analyzed tropical cyclone records from the Caribbean| Gulf of Mexico| and tropical sector of the western North Atlantic over the period 1950-2002 with a focus on the duration| seasonal timing| and geographic position of the events. We found no significant trends in the start date| ending date| or duration of the storm season (defined in various ways) and no trends in the average geographic position of the storms. Furthermore| these measures of hurricane season timing and storm locations were not related to regional sea surface temperature or the northern hemispheric or global temperatures. 6237,2003,2,4,Annual precipitation fields secular variation over global land areas for 1948-2000,The secular variation over the global land annual precipitation (GLAP) fields for 1948-2000 is investigated. Evidence suggests that the GLAP abruptly reduced around 1978 and experienced a decrease of 0.54 mm/a| on average. Fuzzy clustering is used to group the annual precipitation over commonly-used 36 latitudes belts into six belts for examining its secular variation. The results show that| except northern high-latitudes (60degrees-90degrees N) where it is slightly increased| the precipitation is decreased| especially in 35degrees N-35degrees S| and the diminution is the maximum of 0.98 mm/a at tropics. Moreover| identification of 1948-2000 flood/drought years on a global basis is made| showing noticeable interdecadal variations. During the years of warm (cold) events the precipitation decreases (increases) by 15.4 min (14.4 mm) per year| on average. It can be assumed that global warming and frequent ENSO occurrences from the end of the 1970s maybe serve as the root cause of the diminution. 2763,2003,4,4,Antarctic cloud radiative forcing at the surface estimated from the AVHRR Polar Pathfinder and ISCCP D1 datasets| 1985-93,Surface cloud radiative forcing from the newly extended Advanced Very High Resolution Radiometer (AVHRR) Polar Pathfinder (APP-x) dataset and surface cloud radiative forcing calculated using cloud and surface properties from the International Satellite Cloud Climatology Project (ISCCP) D-series product were used in this 9-yr (1985-93) study. On the monthly timescale| clouds were found to have a warming effect on the surface of the Antarctic continent every month of the year in both datasets. Over the ocean poleward of 58.75degreesS| clouds were found to have a warming effect on the surface from March through October in the ISCCP-derived dataset and from April through September in the APP-x dataset. Net surface fluxes from both datasets were validated against net surface fluxes calculated from measurements of upwelling and downwelling shortwave and longwave radiation at the Neumayer and Amundsen-Scott South Pole Stations in the Antarctic. The net all-wave surface flux from the ISCCP-derived dataset was found to be within 0.4-50 W m(-2) of the net all-wave flux at the two stations on the monthly timescale. The APP-x net all-wave surface flux was found to be within 0.9-24 W m(-2). Model sensitivity studies were conducted to gain insight into how the surface radiation budget in a cloudy atmosphere will change if certain cloud and surface properties were to change in association with regional and/or global climate change. The results indicate that the net cloud forcing will be most sensitive to changes in cloud amount| surface reflectance| cloud optical depth| and cloud-top pressure. 6317,2003,3,3,Application of environmental impact assessments to tribo-components - (Part 2) - Effects of oil additives on environmental impact,Life Cycle Assessment (LCA) is conducted for two types of aluminum alloy bush bearings used for automotive transmissions. Equivalent CO2 emission (ECE) is used as the index of the environmental impact for global warming| and is compared through their manufacturing processes. Two types of bush bearings| which are in the market| show little difference in ECE| irrespective of different lining structure if comparison is made by taking a single piece of bearing as the functional unit. However| when the functional unit is defined so that relative life of the bearings based on their anti-wear potential is taken into account| reduction of environmental impact by higher wear resistance of the bearing material and by improved formation of lubricating oil can be estimated quantitatively. This LCA procedure is expected to be a useful tool for an environmentally friendly design of tribo-components.
6261,2003,3,3,Application of life cycle assessment to the LCA case studies single superphosphate production,Goal| Scope and Background. There is a competition between wet and thermal routes for phosphate fertilizers manufacture. In the Brazilian case| the thermal route is represented by thermophosphate. This fertilizer is considered the most adequate one for Brazilian agricultural conditions; its main restriction is the intensive consumption of energy necessary for its production. The wet route uses sulfuric acid to directly produce the single superphosphate (SSP) or the intermediate phosphoric acid| which will be used to result in triple superphosphate (TSP) and ammonium phosphate production. The main restriction of the wet route is the large amount of phosphogypsum generated in phosphoric acid production. Envisaged is an environmental comparison of both routes using LCA methodology. This paper presents the LCA for SSP production. The goal of the study is to establish the Environmental Profile of this fertilizer. Eight impact categories were selected for the study. The system boundaries was defined for a 'cradle to gate' approach| including extraction of natural resources| intermediate products| and production. The SSP System. The SSP system (single superphosphate) comprises the stages of mining and concentration of the phosphate rock| elemental sulfur extraction| production of sulfuric acid| and manufacture of single superphosphate. SSP LCI. The LCI was performed considering the production of 1.0 ton of SSP (single superphosphate) as a Functional Unit. The data collected were developed for different producing companies| all of them located in the same regional area. Allocation criteria of energy and mass were applied to the production of sulfuric acid and manufacture of single superphosphate. The transportation step included either the transport of the mined phosphated rock to the concentration plant or the transport of the phosphate concentrate to the SSP unit. Conclusion| Recommendation and Perspective. The accomplishment of an LCA to SSP production identified the GWP and EP as its meaningful environmental impacts. In reference to global warming| the transportation step was the greatest contributor agent| while the losses of PO4- from the SSP manufacturing were the main cause of ER The most important contribution in terms of water consumption was observed in the concentration step. Finally| the self sufficiency of the sulfuric acid production in energetic terms must be highlighted. The knowledge of the environmental profile of fertilizers is necessary to support LCA studies of agricultural products| a relevant raw material source for many industrial sectors. The method used here may be important for modelling other LCA fertilizer studies. As most of the agricultural raw materials are transferred among different countries| comparisons of the environmental profiles of fertilizers in developed and developing countries are needed. 6137,2003,3,3,Applications of life cycle assessment to NatureWorks (TM) polylactide (PLA) production,NatureWorks(TM) polylactide (PLA)(1) is a versatile polymer produced by Cargill Dow LLC. Cargill Dow is building a global platform of sustainable polymers and chemicals entirely made from renewable resources. Cargill Dow's business philosophy is explained including the role of life cycle assessment (LCA)| a tool used for measuring environmental sustainability and identifying environmental performance-improvement objectives. The paper gives an overview of applications of LCA to PLA production and provides insight into how they are utilized. The first application reviews the contributions to the gross. fossil energy requirement for PLA (54 MJ/kg). In the second one PLA is compared with petrochemical-based polymers using fossil energy use| global warming and water use as the three impact indicators. The last application gives more details about the potential reductions in energy use and greenhouse gasses. Cargill Dow's 5-8 year objective is to decrease the fossil energy use from 54 MJ/kg PLA down to about 7 MJ/kg PLA. The objective for greenhouse gasses is a reduction from +1.8 down to -1.7 kg CO2 equivalents/kg PLA. (C) 2003 Cargill Dow B.V. Published by Elsevier Science Ltd. 2833,2003,4,4,Archaeal lipid biomarkers and isotopic evidence of anaerobic methane oxidation associated with gas hydrates in the Gulf of Mexico,Anaerobic oxidation of methane (AOM) occurs in the Gulf of Mexico gas hydrate systems. Here we show lipid biomarker and isotopic evidence that archaea are involved in AOM. The estimated abundance of total archaeal lipids ranges from 44.8 to 60.4 mug/g (dry sediment) in hydrate-bearing samples but is below detection limit in the hydrate-free sample. The VC values of archaeal lipids range from -69 to -99 parts per thousand in hydrate-bearing samples. These results suggest that biomass of archaea is significantly enhanced through AOM at the gas hydrate deposits. These data also support a currently acknowledged mechanism of AOM mediated by a consortium of sulfate-reducing bacteria and archaea observed in a variety of methane-rich marine settings. Anaerobic oxidation of oil hydrocarbons also occurs in the Gulf of Mexico gas hydrate systems as shown by degradation of n-alkanes (> C-15) in the anoxic sediments. These processes convert hydrocarbons to carbon dioxide and increase pore water alkalinity| which promote the precipitation of enormous volumes of authigenic carbonate rock depleted in C-13. This long-term geologic sequestration of carbon may affect models of global climate change. (C) 2003 Elsevier Science Ltd. All rights reserved. 6263,2003,3,3,Assessing future energy and transport systems: The case of fuel cells - Part 2: Environmental performance,Goal| Scope and Background. Assessing future energy and transport systems is of major importance for providing timely information for decision makers. In the discussion of technology options| fuel cells are often portrayed as attractive options for power plants and automotive applications. However| when analysing these systems| the LCA analyst is confronted with methodological problems| particularly with data gaps and the requirement of forecasting and anticipation of future developments. This series of two papers aims at providing a methodological framework for assessing future energy and transport systems (Part 1) and applies this to the two major application areas of fuel cells (Part 2). Methods. To allow the LCA of future energy and transport systems| forecasting tools like| amongst others| cost estimation methods and process simulation of systems are investigated with respect to the applicability in LCAs of future systems (Part 1). The manufacturing process of an SOFC stack is used as an illustration for the forecasting procedure. In Part 2| detailed LCAs of fuel cell power plants and power trains are carried out including fuel (hydrogen| methanol| gasoline| diesel and natural gas) and energy converter production. To compare it with competing technologies| internal combustion engines (automotive applications) and reciprocating engines| gas turbines and combined cycle plants (stationary applications) are also analysed. Results and Discussion. Principally| the investigated forecasting methods are suitable for future energy system assessment. The selection of the best method depends on different factors such as required ressources| quality of the results and flexibility. In particular| the time horizon of the investigation determines which forecasting tool may be applied. Environmentally relevant process steps exhibiting a significant time dependency shall always be investigated using different independent forecasting tools to ensure stability of the results. The results of the LCA underline that| in general| fuel cells offer advantages in the impact categories usually dominated by pollutant emissions| such as acidification and eutrophication| whereas for global warming and primary energy demand| the situation depends on a set of parameters such as driving cycle and fuel economy ratio in mobile applications and thermal/total efficiencies in stationary applications. For the latter impact categories| the choice of the primary energy carrier for fuel production (renewable or fossil) dominates the impact reduction. With increasing efficiency and improving emission performance of the conventional systems| the competition in both mobile and stationary applications is getting even stronger. The production of the fuel cell system is of low overall significance in stationary applications| whereas in vehicles| the lower life-time of the vehicle leads to a much higher significance of the power train production. Recommendations and Perspectives. In future| rapid technological and energy economic development will bring further advances for both fuel cells and conventional energy converters. Therefore| LCAs at such an early stage of the market development can only be considered preliminary. It is an essential requirement to accompany the ongoing research and development with iterative LCAs| constantly pointing at environmental hot spots and bottlenecks. 6262,2003,3,4,Assessing future energy and transport systems: The case of fuel cells Part I: Methodological aspects,Goal| Scope and Background. Assessing future energy and transport systems is of major importance for providing timely information for decision makers. In the discussion of technology options| fuel cells are often portrayed as attractive options for power plants and automotive applications. However| when analysing these systems| the LCA analyst is confronted with methodological problems| particularly with data gaps and the requirement of an anticipation of future developments. This series of two papers aims at providing a methodological framework for assessing future energy and transport systems (Part 1) and applies this to the two major application areas of fuel cells (Part 2). Methods. To allow the LCA of future energy and transport systems forecasting tools like| amongst others| cost estimation methods and process simulation of systems are investigated with respect to the applicability in LCAs of future systems (Part 1). The manufacturing process of an SOFC stack is used as an illustration for the forecasting procedure. In Part 2| detailed LCAs of fuel cell power plants and power trains are carried out including fuel (hydrogen| methanol| gasoline| diesel and natural gas) and energy converter production. To compare it with competing technologies| internal combustion engines (automotive applications) and reciprocating engines| gas turbines and combined cycle plants (stationary applications) are analysed as well. Results and Discussion. Principally| the investigated forecasting methods are suitable for future energy system assessment. The selection of the best method depends on different factors such as required ressources| quality of the results and flexibility. In particular| the time horizon of the investigation determines which forecasting tool may be applied. Environmentally relevant process steps exhibiting a significant time dependency shall always be investigated using different independent forecasting tools to ensure stability of the results. The results of the LCA (Part 2) underline that principally| fuel cells offer advantages in the impact categories which are typically dominated by pollutant emissions| such as acidification and eutrophication| whereas for global warming and primary energy demand| the situation depends on a set of parameters such as driving cycle and fuel economy ratio in mobile applications and thermal/total efficiencies in stationary applications. For the latter impact categories| the choice of the primary energy carrier for fuel production (renewable or fossil) dominates the impact reduction| With increasing efficiency and improving emission performance of the conventional systems| the competition regarding all impact categories in both mobile and stationary applications is getting even stronger. The production of the fuel cell system is of low overall significance in stationary applications| whereas in automotive applications| the production of the fuel cell power train and required materials leads to increased impacts compared to internal combustion engines and thus reduces the achievable environmental impact reduction. Recommendations and Perspectives. The rapid technological and energy economic development will bring further advances for both fuel cells and conventional energy converters. Therefore| LCAs at such an early stage of the market development can only be considered preliminary. It is an essential requirement to accompany the ongoing research and development with iterative LCAs| constantly pointing at environmental hot spots and bottlenecks. 2710,2003,3,3,Assessing the potential of renewable energy sources in Turkey,To meet Turkey's growing energy demand| the installed electric power capacity of 27.8 GW in 2001 has to be doubled by 2010 and increased fourfold by 2020. The difference between Turkey's total primary energy supply (TPES) of from its own sources and total final consumption (TFC) is projected grow from 1 quad (1.06-2.06) in 1999 to 5.71 quads (2.79-8.5) in 2020 (1 quad = 293.071 TWh). Turkey's limited amount of fossil fuels has a present average ratio of proved reserves of 97.38 quads to production rate of 3.2 quads yr(-1) of about 30 years. Turkey's reliance on fossil fuel-based energy systems to meet the growing demand is most likely to exacerbate the issues of energy insecurity| national environmental degradation| and global climate change in increasing proportions. Economically-feasible renewable energy potential in Turkey is estimated at a total of ca. 1.69 quads yr(-1) (495.4 TWh yr(-1)) with the potential for 0.67 quads yr(-1) (196.7 TWh yr(-1)) of biomass energy| 0.42 quads yr(-1) (124 TWh yr(-1)) of hydropower| 0.35 quads yr(-1) (102.3 TWh yr(-1)) of solar energy| 0.17 quads yr(-1) (50 TWh yr(-1)) of wind energy| and 0.08 quads yr(-1) (22.4 TWh yr(-1)) of geothermal energy. Pursuit and implementation of sustainability-based energy policy could provide about 90 and 35% of Turkey's total energy supply and consumption projected in 2010| respectively. Utilization of renewable energy technologies for electricity generation would necessitate about 23.2 Mha (29.8%) of Turkey's land resources. (C) 2003 Elsevier Science Ltd. All rights reserved. 2782,2003,2,4,Assessing winter wheat responses to climate change scenarios: A simulation study in the US Great Plains,Hard red winter wheat (Triticum aestivum L.) is a major crop in the Great Plains region of the U. S. The goal of this assessment effort was to investigate the influence of two contrasting global climate change projections (U. K. Hadley Center for Climate Prediction and Research and Canadian Centre for Climate Modelling and Analysis) on the yield and percent kernel nitrogen content of winter wheat at three locations in Nebraska. These three locations represent sub-humid and semi arid areas and the transition between these areas and are also representative of major portions of the winter wheat growing areas of the central Great Plains. Climate scenarios based on each of the projections for each location were developed using the LARS-WG weather generator along with data from automated weather stations. CERES-Wheat was used to simulate the responses for two contrasting cultivars of wheat using two sowing dates. The first sowing date represented current sowing dates appropriate for each location. The second sowing date was later and represents the approximate date when the mean air temperature from the climate scenarios is the same as the mean air temperature from the actual climate data at the current sowing dates. The yield and percent kernel nitrogen content using the two climate scenarios generally decrease going from the sub-humid eastern to the semi arid western parts of Nebraska. Results from these simulations indicate that yield and percent kernel nitrogen content using the two climate scenarios could not both be maintained at levels currently simulated. Protein content (directly related to kernel nitrogen content) and end-use quality are the primary determinants for the use of hard red winter wheat in baked goods. Nitrogen management and new cultivars| which can enhance the uptake and translocation of nitrogen| will be proactive steps to meet the challenges of global climate change as represented by these climate scenarios. 6299,2003,3,3,Assessment of the environmental impact of management measures for the biodegradable fraction of municipal solid waste in Sao Paulo City,There is increasing concern about landfilling of biodegradable wastes. Therefore| biological treatment processes such as composting and biogasification have been considered as alternative strategies for managing those wastes. In this work| life cycle assessment was employed to compare the environmental impacts of landfilling| composting| and biological treatment of municipal solid waste in Sao Paulo City| Brazil. Energy consumption| recovered resources| and emissions to air and water were quantified and analyzed in terms of their potential contribution to global warming| acidification| and nutrient enrichment impact. The results demonstrated that processes that require high levels of energy consumption| such as wastewater treatment| play an important role in the outcome of environmental impact potentials. It was found that the landfilling of all waste is generally the worst strategy from an environmental point of view. However| significant reductions in the resulting impacts can be accomplished through biogasification and composting of the biodegradable fraction. Regarding composting| the application of a biofilter for gas treatment reduced significantly the gaseous emissions. (C) 2003 Elsevier Ltd. All rights reserved. 6186,2003,4,4,Atmospheric chemistry of C2F5C(O)CF(CF3)(2): Photolysis and reaction with Cl atoms| OH radicals| and ozone,Smog-chamber Fourier-transform infrared (FTIR) techniques were used to study the kinetics and photochemistry of C2F5C(O)CF(CF3)(2) in 50-700 Torr of air at 296 K. Upper limits for the rate constants of reactions of Cl atoms| OH radicals| and ozone with C2F5C(O)CF(CF3)(2) were established: k(Cl) < 1.7 x 10(-19)| k(OH) < 5 x 10(-16)| and k(O3) < 4 x 10(-22) cm(3) molecule(-1) s(-1). The ultraviolet absorption spectrum Of C2F5C(O)CF(CF3)(2) has a maximum at 305 nm where sigma(e) = 6.8 x 10(-20) cm(2) molecule(-1). C2F5C(O)CF(CF3)(2) is removed from the atmosphere by photolysis| which occurs on a time scale of approximately 1-2 weeks. As a result of its short atmospheric lifetime| the global warming potential of C2F5C(O)CF(CF3)(2) is negligible. 2716,2003,2,4,Atmospheric CO2 increase benefits symbiotic N-2 fixation by legumes under drought,Leguminous plants are considered to have a Competitive advantage under global climate change because of increased rates of symbiotic nitrogen (ND fixation in response to increased atmospheric CO2. However| this hypothetical advantage may not be realized under actual climate change due to the associated increase in frequency and duration of drought| as N-2 fixation in legume species such as soybean| is sensitive to soil drying. Yet| it has been discovered that N-2 fixation in soybean becomes drought-tolerant under increased CO2 concentration. The reduced susceptibility of N-2 fixation to drought was associated with an increase in total nonstructural carbohydrates and a decrease in ureides in leaves. These results empirically indicate that legumes will have substantial comparative advantage over cereals under climate change. 6034,2003,4,2,Atmospheric perfluorocarbons,Collectively| man-made emissions of a few greenhouse gases may cause about the same amount of global warming as increasing carbon dioxide. Among the most potent of these non-CO2 greenhouse gases are the perfluorocarbons that have extraordinarily long atmospheric lifetimes of 10 000 to more than 50 000 yr. We report atmospheric concentrations over two decades| between 1978 and 1997| of the three most abundant perfluorocarbons-CF4| C2F6| and C3F8-and delineate the sources that account for the present abundances and trends. We show that C2F6 and C3F8 are present at only 2.9 and 0.2 pptv| respectively. CF4 is the most abundant perfluorocarbon at 74 pptv (in 1997) of which about 40 pptv are from natural emissions| 33 pptv from aluminum manufacturing| and 1 pptv from the semiconductor industry. The increasing trend of CF4 has slowed in recent years due to the major reductions in the emission rate per ton of aluminum produced. The effect of the falling emission factor is partially offset by increased production and increasing use by the semiconductor industry. 2770,2003,4,4,Atmospheric sulfur deposition alters pathways of gaseous carbon production in peatlands,[1] Peatlands represent large carbon (C) reservoirs that can act as a source or sink for greenhouse gases. The response of peatland gaseous C fluxes to global climate change and atmospheric sulfate deposition| however| remains uncertain. Methanogenesis is thought to be one of the most important anaerobic C mineralization pathways in peatlands| especially in regions where input of sulfate from acid deposition is low. However| sulfate reduction has been quantified rarely in freshwater wetlands. Here we report greater anaerobic C flow through sulfate reduction than through methanogenesis at all sites situated along a global atmospheric sulfur deposition gradient. Stoichiometric mass balance suggests that fermentation is a dominant anaerobic C mineralization pathway in unpolluted peatlands| while methanogenesis contributed minimally to total anaerobic carbon mineralization in these sites. Furthermore| global increases of atmospheric sulfur deposition minimize the impacts of climatic warming by simultaneously decreasing rates of methanogenesis while causing little change in rates of total anaerobic C mineralization in Sphagnum-dominated peatlands. 2724,2003,2,4,Avian migration phenology and global climate change,There is mounting evidence that global climate change has extended growing seasons| changed distribution patterns| and altered the phenology of flowering| breeding| and migration. For migratory birds| the timing of arrival on breeding territories and over-wintering grounds is a key determinant of reproductive success| survivorship| and fitness. But we know little of the factors controlling earlier passage in long-distance migrants. Over the past 30 years in Oxfordshire| U.K.| the average arrival and departure dates of 20 migrant bird species have both advanced by 8 days; consequently| the overall residence time in Oxfordshire has remained unchanged. The timing of arrival has advanced in relation to increasing winter temperatures in sub-Saharan Africa| whereas the timing of departure has advanced after elevated summer temperatures in Oxfordshire. This finding demonstrates that migratory phenology is quite likely to be affected by global climate change and links events in tropical winter quarters with those in temperate breeding areas. 6156,2003,4,4,Benthic macroinvertebrates in Swedish streams: community structure| taxon richness| and environmental relations,Spatial scale| e.g. from the stream channel| riparian zone| and catchment to the regional and global scale is currently an important topic in running water management and bioassessment. An increased knowledge of how the biota is affected by human alterations and management measures taken at different spatial scales is critical for improving the ecological quality of running waters. However| more knowledge is needed to better understand the relationship between environmental factors at different spatial scales| assemblage structure and taxon richness of running water organisms. In this study| benthic macroinvertebrate data from 628 randomly selected streams were analysed for geographical and environmental relationships. The dataset also included 100 environmental variables| from local measures such as in-stream substratum and vegetation type| catchment vegetation and land-use| and regional variables such as latitude and longitude. Cluster analysis of the macroinvertebrate data showed a continuous gradient in taxonomic composition among the cluster groups from north to south. Both locally measured variables (e.g. water chemistry| substratum composition) and regional factors (e.g. latitude| longitude| and an ecoregional delineation) were important for explaining the variation in assemblage structure and taxon richness for stream benthic macroinvertebrates. This result is of importance when planning conservation and management measurements| implementing large-scale biomonitoring programs| and predicting how human alterations (e.g. global warming) will affect running water ecosystems. 2765,2003,5,4,Beryllium-10 dating of Mount Everest moraines indicates a strong monsoon influence and glacial synchroneity throughout the Himalaya,Moraine successions in glaciated valleys south of Mount Everest provide evidence for at least eight glacial advances during the late Quaternary. Cosmogenic radionuclide (CRN) surface exposure dating of moraine boulders defines the timing of each glacial advance and refines the previous glacial chronologies. The CRN data show that glaciation was most extensive during the early part of the last glacial (marine oxygen isotype stage [MIS] 3 and earlier)| but limited during MIS 2 (the global Last Glacial Maximum) and the Holocene. A previously assumed Neoglacial advance is dated to 3.6 +/- 0.3 ka and the CRN dates confirm a glacial advance ca. 1 ka. These results show that glaciations on the south side of Everest were not synchronous with the advance of Northern Hemisphere ice sheets| yet glaciations within the Himalaya| the world's highest mountain belt| were synchronous during the late Quaternary. The existence of glacial advances during times of increased insolation suggests that enhanced moisture delivered by an active south Asian summer monsoon is largely responsible for glacial advances in this part of the Himalaya. These data allow us to quantify the importance of global climate change and monsoon influence on glaciation in the Himalaya. 6247,2003,3,4,Biological impacts of deep-sea carbon dioxide injection inferred from indices of physiological performance,A recent proposal to store anthropogenic carbon dioxide in the deep ocean is assessed here with regard to the impacts on deep-living fauna. The stability of the deepsea has allowed the evolution of species ill-equipped to withstand rapid environmental changes. Low metabolic rates of most deep-sea species are correlated with low capacities for pH buffering and low concentrations of ion-transport proteins. Changes in seawater carbon dioxide partial pressure (Pco(2)) may thus lead to large cellular Pco(2) and pH changes. Oxygen transport proteins of deepsea animals are also highly sensitive to changes in pH. Acidosis leads to metabolic suppression| reduced protein synthesis| respiratory stress| reduced metabolic scope and| ultimately| death. Deep-sea CO2 injection as a means of controlling atmospheric CO2 levels should be assessed with careful consideration of potential biological impacts. In order to properly evaluate the risks within a relevant timeframe| a much more aggressive approach to research is warranted. 2830,2003,2,4,Biological indicators in the Caribbean coastal zone and their role in integrated coastal management,Caribbean coastal ecosystems are increasingly being threatened by natural and anthropogenic factors. The scale of these factors is at local| national| regional and global levels. Threats include the effects of fisheries and extraction| eutrophication| siltation| and pollution as well as global climate events such as El Nino and global climate change. Integrated coastal management (ICM) should clearly demonstrate the adverse effects of environmental impacts| thus justifying the need for mitigation and should evaluate the success of management efforts. ICM requires robust indicators that gauge the 'health' of the coast in relation to environmental| social and economic activities. Biological indicators (bioindicators) offer a signal of the biological condition in an ecosystem. Using bioindicators as an early warning of pollution or degradation in an ecosystem can help sustain critical resources. Biological indicators in the Caribbean are focused around particular ecosystems| especially coral reefs| seagrass beds and mangrove forests and include a range of biological parameters relating to particular species| groups of species and biological processes. The use of these indicators is critically reviewed and the presence or absence of a relevant| framework for their use in Caribbean ICM programs is discussed. (C) 2003 Elsevier Science Ltd. All rights reserved. 6029,2003,2,4,Biological pump in northwestern North Pacific,The northwestern North Pacific is considered to be one of the most productive areas in the global ocean. Although the marginal zones along the Japanese and Kuril islands| Kamchatka Peninsula| and Aleutian Islands are certainly productive| recent studies do not always show high primary production values in the western subarctic gyre (WSG). In addition| a recent analysis of the biological pump in the WSG showed that| in contrast to what was previously reported| the vertical change of the particulate organic carbon flux with depth is large. Nevertheless| the biological pump in the northwestern North Pacific may function to draw down the partial pressure of CO(2) in the surface water because the ratio of the organic carbon flux to inorganic carbon flux (C(or)/C(inorg))| the export flux| and the export ratio from the surface water are higher than those in other oceans. This article also introduces recent research on changes to the biological pump that might have been caused by global warming. 2777,2003,3,2,Biotic landfill cover treatments for mitigating methane emissions,Landfill methane (CH4) emissions have been cited as one of the anthropogenic gas releases that can and should be controlled to reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumption of the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH4 emission reductions achieved by gas collection or provide a sole means to consume CH4 at small landfills that do not have active gas collection systems. Field studies indicate that high levels of CH4 removal can be achieved by optimizing natural soil microbial processes. Further| during biotic conversion| not all of the CH4 carbon is converted to carbon dioxide (CO2) gas and released to the atmosphere; some of it will be sequestered in microbial biomass. Because biotic covers can employ residuals from other municipal processes| financial benefits can also accrue from avoided costs for residuals disposal. 6141,2003,2,4,Body size| performance and fitness in Galapagos marine iguanas,Complex organismal traits such as body size are influenced by innumerable selective pressures| making the prediction of evolutionary trajectories for those traits difficult. A potentially powerful way to predict fitness in natural systems is to study the composite response of individuals in terms of performance measures| such as foraging or reproductive performance. Once key performance measures are identified in this top-down approach| we can determine the underlying physiological mechanisms and gain predictive power over long-term evolutionary processes. Here we use marine iguanas as a model system where body size differs by more than one order of magnitude between island populations. We identified foraging efficiency as the main performance measure that constrains body size. Mechanistically| foraging performance is determined by food pasture height and the thermal environment| influencing intake and digestion. Stress hormones may be a flexible way of influencing an individual's response to low-food situations that may be caused by high population density| famines| or anthropogenic disturbances like oil spills. Reproductive performance| on the other hand| increases with body size and is mediated by higher survival of larger hatchlings from larger females and increased mating success of larger males. Reproductive performance of males may be adjusted via plastic hormonal feedback mechanisms that allow individuals to assess their social rank annually within the current population size structure. When integrated| these data suggest that reproductive performance favors increased body size (influenced by reproductive hormones)| with an overall limit imposed by foraging performance (influenced by stress hormones). Based on our mechanistic understanding of individual performances we predicted an evolutionary increase in maximum body size caused by global warming trends. We support this prediction using specimens collected during 1905. We also show in a common-garden experiment that body size may have a genetic component in iguanids. This 'performance paradigm' allows predictions about adaptive evolution in natural populations. 2750,2003,2,4,Can soil temperature direct the composition of high arctic plant communities?,Low temperatures exert a primary constraint on the Growth of high arctic vascular plants. However| investigations into the impact of temperature on high arctic plants rarely separate out the role of air and soil temperatures| and few data exist to indicate whether soil temperatures alone can significantly influence the growth of high arctic vascular plants in a manner that might direct community composition. We examined the response of high arctic plants of three functional types (grasses| sedges/rushes and non-graminoids) to manipulated soil temperature under common air temperature conditions. Target plants| within intact soil cores| were placed in water baths at a range of temperatures between 4.9 and 15.3degreesC for one growing season. Grasses responded most rapidly to increased soil temperature| with increased total live plant mass. above-ground live mass and total below-ground live mass| with non-graminoids having the lowest| and sedges/ rushes an intermediate degree of response. The ratio of above-ground live mass to total live mass increased in all growth forms. Grasses. in particular| responded to enhanced soil temperatures by increasing shoot size rather than shoot number. In all growth forms the mass of root tissue beneath the moss layer increased significantly and to a similar extent with increasing soil temperature. These results clearly indicate that different growth forms| although collected from the same plant community| respond differently to changes in soil temperature. As a consequence| factors influencing soil temperature in high arctic ecosystems| such as global climate change or herbivory (which leads to reduced moss depth and increased soil temperatures)| may also direct chances in vascular plant community composition. 6162,2003,2,4,Can solar variability explain global warming since 1970?,[1] The magnitude of the Sun's influence on climate has been a subject of intense debate. Estimates of this magnitude are generally based on assumptions regarding the forcing due to solar irradiance variations and climate modeling. This approach suffers from uncertainties that are difficult to estimate. Such uncertainties are introduced because the employed models may not include important but complex processes or mechanisms or may treat these in too simplified a manner. Here we take a more empirical approach. We employ time series of the most relevant solar quantities| the total and UV irradiance between 1856 and 1999 and the cosmic rays flux between 1868 and 1999. The time series are constructed using direct measurements wherever possible and reconstructions based on models and proxies at earlier times. These time series are compared with the climate record for the period 1856 to 1970. The solar records are scaled such that statistically the solar contribution to climate is as large as possible in this period. Under this assumption we repeat the comparison but now including the period 1970-1999. This comparison shows without requiring any recourse to modeling that since roughly 1970 the solar influence on climate (through the channels considered here) cannot have been dominant. In particular| the Sun cannot have contributed more than 30% to the steep temperature increase that has taken place since then| irrespective of which of the three considered channels is the dominant one determining Sun-climate interactions: tropospheric heating caused by changes in total solar irradiance| stratospheric chemistry influenced by changes in the solar UV spectrum| or cloud coverage affected by the cosmic ray flux. 6109,2003,2,4,Carbon dioxide and temperature effects on evapotranspiration and water use efficiency of soybean,Rising CO2 and potential global warming will cause changes in evapotranspiration (ET). Our research objective was to determine the impact of CO2 and air temperature on canopy ET| water use efficiency (WUE)| foliage temperature| and canopy resistance (Re) of soybean [Glycine max (L.) Merr.]. Plants were grown in sunlit| controlled-environment chambers at cyclic maximum/minimum air temperatures from 28/18degreesC to 44/34degreesC and CO2 of 350 or 700 mumol mol(-1). Maximum ET rate in the early afternoon at 35 d after planting ranged from 7.5 mol m(-2) s(-1) at 28/18degreesC to 19.0 Mol m(-2) s(-1) at 44/34degreesC. Daily ET during the middle of the season ranged from 260 mol H2O m(-2) d(-1)(4.7 mm d(-1)) at 28/18degreesC to 660 mol H2O m(-2) d(-1)(11.9 mm d(-1)) at 44/34degreesC. Mean daily ET was linearly related to mean air temperature (T-air) as: [Mean daily ET = 21.4 X T-air - 306| r(2) = 0.99 (mol H2O m(-2) d(-1))| or mean daily ET = 0.385 X T-air - 5.5 (mm d(-1))]. Doubled CO2 caused a 9% decrease in ET at 28/18degreesC| but CO2 had little effect at 40/30degreesC or 44/34degreesC. Whole-day WUE declined linearly with air temperature| with a slope of -0.150 [(mumol CO2 mmol(-1) H2O) degreesC(-1)]. Changes in ET and WUE were governed by changes in foliage temperature and Re. In conclusion| increases in temperature anticipated by climate change could more than offset decreases of ET that would be caused by increases in CO2. 2736,2003,3,3,Carbon dynamics and land-use choices: building a regional-scale multidisciplinary model,Policy enabling tropical forests to approach their potential contribution to global-climate-change mitigation requires forecasts of land use and carbon storage on a large scale over long periods. In this paper| we present an integrated modeling methodology that addresses these needs. We model the dynamics of the human land-use system and of C pools contained in each ecosystem| as well as their interactions. The model is national scale| and is currently applied in a preliminary way to Costa Rica using data spanning a period of over 50 years. It combines an ecological process model| parameterized using field and other data| with an economic model| estimated using historical data to ensure a close link to actual behavior. These two models are linked so that ecological conditions affect land-use choices and vice versa. The integrated model predicts land use and its consequences for C storage for policy scenarios. These predictions can be used to create baselines| reward sequestration| and estimate the value in both environmental and economic terms of including C sequestration in tropical forests as part of the efforts to mitigate global climate change. The model can also be used to assess the benefits from costly activities to increase accuracy and thus reduce errors and their societal costs. (C) 2003 Elsevier Ltd. All rights reserved. 6104,2003,4,4,Carbon geochemistry of cold seeps: Methane fluxes and transformation in sediments from Kazan mud volcano| eastern Mediterranean Sea,Despite growing concerns about potential enhancement of global warming and slope failure by methane produced by gas hydrate dissociation| much uncertainty surrounds estimates of gas hydrate reservoir sizes| as well as methane fluxes and oxidation rates at the sea floor. For cold seep sediments of the eastern Mediterranean Sea| depth-dependent methane concentrations and rates of anaerobic oxidation of methane (AOM) are constrained by modeling the measured pore-water sulfate profile. The calculated dissolved methane distribution and flux are sensitive to the advective flow velocity| which is estimated from the depth distributions of conservative pore-water constituents (Na| B). Near-complete anaerobic oxidation of the upward methane flux of similar to 6.0 mol m(-2) yr(-1) is supported by the depth distributions of indicative biomarkers| and the carbon isotopic compositions of organic matter and dissolved inorganic carbon. Pore-water and solid-phase data are consistent with a narrow depth interval of AOM| 14-18 cm below the sediment-water interface. Based on an isotopic mass balance| the biomass of the microbial population carrying out oxidation of methane coupled to sulfate reduction at the given methane flux represents similar to 20% of the total organic carbon| which is a significant pool of in situ formed organic matter. Model results indicate that the asymptotic methane concentration is reached a few meters below the sediment surface. The predicted asymptotic concentration is close to the in situ saturation value with respect to gas hydrate| suggesting that the rate of shallow gas hydrate formation is controlled by the ascending methane flux. The proposed model approach can be used to predict the formation of gas hydrate| and to quantify methane fluxes plus transformation rates in surface sediments where fluid advection is an important transport mechanism. (C) 2003 Elsevier Science B.V. All rights reserved. 2759,2003,5,3,Carbon isotopes across the Eocene-Oligocene boundary sequence of Kutch| western India: Implications to oceanic productivity and pCO(2) change,[1] Analyses of foraminiferal delta(18)O (delta(18)O(carb))| delta(13)C (delta(13)C(carb)) and bulk organic matter (delta(13)C(org)) across a tropical Eocene/Oligocene boundary (EOB) section from Kutch basin| western India show that the ocean cooling ( at least similar to3degreesC) is coincident with a rapid enrichment (similar to3parts per thousand) in delta(13)C(org) but depletion (similar to1.5parts per thousand) in delta(13)C(carb). The decrease in pCO(2) in ocean-atmosphere system across the boundary| possibly resulting from enhanced silicate weathering in rising Himalayas and accompanied organic carbon burial in ocean| caused the cooling and delta(13)C(org) enrichment. The end-Eocene climatic stress decreased the oceanic productivity (and delta(13)C(carb)) eventually causing extinction of larger benthic foraminiferal community. The data suggest a critical role of tropical ocean and direct forcing of CO2 on global climate change at least for this crucial Cenozoic transition. 2786,2003,5,4,Catastrophic arid episodes in the Eastern Mediterranean linked with the North Atlantic Heinrich events,The response of continental climate to the well-documented climate oscillations during the last glacial period has been a subject of intense interest| yet much less is known about the influence on regional continental climates than in the marine or polar realms of Earth. The detailed lake-level history of the closed Lake Lisan (paleo-Dead Sea) in the Middle East has been reconstructed from shoreline indications and high-resolution U-Th and C-14 chronologies| thus providing data on the response of the lake's catchment area to the climate changes during the corresponding period. We present a correlation between the newly developed Lake Lisan level curve for the past 55 k.y: and the North Atlantic Heinrich events. The correlation indicates a closely connected climate response between these North Atlantic events and the hydrologic conditions that prevailed in the Eastern Mediterranean. Our findings show that although the generally cooler conditions that prevailed during the last glaciation favored high levels of the lake| catastrophic events in the North Atlantic| which are associated with maximum cooling| have been responsible for droughts in the Eastern Mediterranean. We infer that cold-water input to the Mediterranean originating in the collapse of the North Atlantic Deep Water circulation caused the reduction of evaporation and less precipitation in the Eastern Mediterranean. 5977,2003,2,4,Catastrophic die-off of Peary caribou on the western queen Elizabeth Islands| Canadian High Arctic,The Peary caribou (Rangifer tarandus pearyi) is an endangered species in Canada| having been in an overall decline since 1961. Sightings of Peary caribou were compared from two aerial searches| in 1993 and 1998| on Bathurst and its neighbouring islands| western Queen Elizabeth Islands in the Canadian High Arctic. The comparison indicated a near-total (98%) cataclysmic decline in the number of Peary caribou seen per unit of search effort. In summer 1993| 2400 caribou were counted during 33.8 h of low-level helicopter searches. In contrast| in summer 1998| only 43 caribou were seen within the same area during 35.2 h of low-level| helicopter searches. The frequency of observation was markedly different: 118.3 caribou/100 min in 1993| but only 2.0 caribou/100 min in 1998. The number of carcasses indicated that the decline resulted from deaths and not from mass emigration. Males died at a disproportionately higher rate than females among all 1+ yr old caribou| and bulls (4+ yr) compared to cows (3+ yr) had died at an even greater rate. Widespread| prolonged| exceptionally severe snow and ice conditions from 1994 95 to 1996-97 caused the die-off. Trends in snowfall are consistent with predictions for global warming in the western Canadian High Arctic. Future climate change may increase the frequency of years with unfavorable snow and ice conditions| which could prevent or at least impede future recovery of Peary caribou populations on the western Queen Elizabeth Islands| particularly to sizes that would support subsistence harvesting. 6123,2003,5,4,Centennial-scale dry-wet variations in East Asia,This study attempts to combine four independent long-term climatic data and modern observations into one cohesive set; to describe the spatial and temporal patterns of variability of dry and wet periods in East Asia over the past one thousand years; and to examine physical causes of the pattern variations. The data include the 220-year observed precipitation in Seoul| South Korea| the dryness-wetness intensity data in eastern China for the last 530 years| and other two independent chronologies of dryness-wetness grades in the past millennium in eastern China based on instrumental observations and historical documents. Various analysis methods including wavelet transform and rotated empirical orthogonal function were used in revealing climate variations from these datasets. Major results show that the dry and wet anomalies initially appeared in the north part of eastern China and then migrated southward to affect south China. This process is repeated about every 70 years. However| in contrast in the last two decades of the twentieth century a dry situation appeared in north China and a wet climate predominated in the south part of the country. The multidecadal variations of the monsoon circulation in East Asia and the thermal contrast between inland Asia and its surrounding oceans may contribute to the dry-wet phase alternation or the migration of dry-wet anomalies. In regional scale variations| a consistent dry or wet pattern was observed spreading from the lower Yangtze River valley to South Korea. Frequencies of severe dry-wet situations were low in the eighteenth and nineteenth century and they were higher in the twentieth century. The recent increasing trend in frequencies of severe dry-wet chances occurred along with global warming and regional climatic changes in China. 6160,2003,3,4,Central and individual air-conditioning systems - A comparison of environmental impacts and resource consumption in a life cycle perspective,This paper compares individual (split) and central systems of air-conditioning in a life cycle perspective| taking into account the environmental impacts and resource consumption during resource extraction| material production| production of the air-conditioning units| their use| disposal and recycling. Life cycle assessment (LCA) is used in conducting this comparison. Central systems have a longer lifetime than individual systems| lower electricity consumption and maintenance requirements during the use phase| and a higher recycling potential during the disposal phase. However| to transfer cool air| central systems use a large quantity of water pipes or air ducts| the production of which contributes significantly to resource use. The LCA study reveals that| on the whole| the central systems generally use less resources than split systems and result in lower environmental impacts. The paper suggests a need for producers of air-conditioners to consider a change from being suppliers of air-conditioning hardware to being suppliers of cool air in order to overcome the initial cost constraints of central systems and realize their environmental and economic improvement potential to the benefit of the environment| and the industry as well as customers. 6304,2003,2,4,Changes in biologically active ultraviolet radiation reaching the Earth's surface,Since publication of the 1998 UNEP Assessment| there has been continued rapid expansion of the literature on UV-B radiation. Many measurements have demonstrated the inverse relationship between column ozone amount and UV radiation| and in a few cases long-term increases due to ozone decreases-have been identified. The quantity| quality and availability of ground-based UV measurements relevant to assessing the environmental impacts of ozone changes continue to improve. Recent studies have contributed to delineating regional and temporal differences due to aerosols| clouds| and ozone. Improvements in radiative transfer modelling capability now enable more accurate characterization of clouds| snow-cover| and topographical effects. A standardized scale for reporting UV to the public has gained wide acceptance. There has been increased use of satellite data to estimate geographic variability and trends in UV. Progress has been made in assessing the utility of satellite retrievals of UV radiation by comparison with measurements at the Earth's surface. Global climatologies of UV radiation are now available on the Internet. Anthropogenic aerosols play a more important role in attenuating UV irradiances than has been assumed previously| and this will have implications for the accuracy of UV retrievals from satellite data. Progress has been made inferring historical levels of UV| radiation using measurements of ozone (from satellites or from ground-based networks) in conjunction with measurements of total solar radiation obtained from extensive meteorological networks. We cannot yet be sure whether global ozone has reached a minimum. Atmospheric chlorine concentrations are beginning to decrease. However| bromine concentrations are still increasing. While these halogen concentrations remain high| the ozone layer remains vulnerable to further depletion from events such as volcanic eruptions that inject material into the stratosphere. Interactions between global warming and ozone depletion could delay ozone recovery by several years| and this topic remains an area of intense research interest. Future changes in greenhouse gases will affect the future evolution of ozone through chemical| radiative| and dynamic processes. In this highly coupled system| an evaluation of the relative importance of these processes is difficult; studies are ongoing. A reliable assessment of these effects on total column ozone is limited by uncertainties in lower stratospheric response to these changes. At several sites| changes in UV differ from those expected from ozone changes alone| possibly as a result of long-term changes in aerosols| snow cover| or clouds. This indicates a possible interaction between climate change and UV radiation. Cloud reflectance measured by satellite has shown a long-term increase at some locations| especially in the Antarctic region| but also in Central Europe| which would tend to reduce the UV radiation. Even with the expected decreases in atmospheric chlorine| it will be several years before the beginning of an ozone recovery can be unambiguously identified at individual locations. Because UV-B is more variable than ozone| any identification of its recovery would be further delayed. 6134,2003,2,4,Changes in flowering and abundance of Delphinium nuttallianum (Ranunculaceae) in response to a subalpine climate warming experiment,High-altitude and high-latitude sites are expected to be very sensitive to global warming| because the biological activity of most plants is restricted by the length of the short snowfree season| which is determined by climate. Long-term observational studies in subalpine meadows of the Colorado Rocky Mountains have shown a strong positive correlation between snowpack and flower production by the forb Delphinium nuttallianum. If a warmer climate reduces annual snowfall in this region then global warming might reduce fitness in D. nuttallianum. In this article we report effects of experimental warming on the abundance and flower production of D. nuttallianum. Plant abundance (both flowering and vegetative plants) was slightly greater on warmed than control plots prior to initiation of the warming treatment in 1991. Since 1994 experimental warming has had a negative effect on D. nuttallianum flower production| reducing both the abundance of flowering plants and the total number of flowers per plant. Flower bud abortion was higher in the heated plots than the controls only in 1994 and 1999. Results from both the warming experiment and analyses of unmanipulated long-term plots suggest that global warming may affect the fecundity of D. nuttallianum| which may have cascading effects on the pollinators that depend on it and on the fecundity of plants that share similar pollinators. 6257,2003,2,4,Changes in seasonal deaths from myocardial infarction,Background: Cardiovascular disease is the major contributor to excess morbidity and mortality in winter. With the rise in temperatures through global warming| and the use of central heating and air conditioning| this seasonal variation may be declining. Aim: To study possible changes in seasonal variation in case-fatality rates of myocardial infarction (MI)| in men and women| over a 20-year period and compare this with possible environmental influences. Design: Retrospective analysis of death certificate and climatological data. Methods: We analysed all monthly death certificate data from Northern Ireland| for death caused by MI from 1979 through 1998 (n = 68 683). Mortality data were standardized to a single reference group for the whole period. Seasonal variation in mortality and in environmental variables was described using the cosinor model. Results: A total of 29 875 women and 38 808 men died from MI during the 20-year period. A significant decrease in mortality from MI was observed in both sexes| accompanied by a non-significant decline in the amplitude of the seasonal rhythm over the study period. Low temperature was associated with higher mortality rates from MI. Discussion: We have documented an overall decline in cardiovascular mortality from 1979 to 1998 together with a small but non-significant decrease in seasonal variation. While improvements in medical care| lifestyle| housing and diet may have contributed to the observed decline in mortality rate| seasonal fluctuations remain a significant problem. 5989,2003,2,4,Changes in shallow lake functioning: response to climate change and nutrient reduction,Nutrient| phytoplankton and zooplankton dynamics have been monitored intensively at Loch Leven for 34 years. The data collected reveal a decline in phosphorus concentrations| following major reductions in external nutrient loading| and large changes in its seasonal availability| particularly in recent years. More striking has been an increasing trend in water temperatures| annual means increasing by about 1degreesC over the 34 years| with even greater increases observed for winter and spring periods. In response to these changes| there has been a general pattern of decline in measures of phytoplankton biomass (chlorophyll| concentrations). Closer inspection reveals that the detailed response is| however| not so consistent with the environmental trends. A significant decline in chlorophyll| concentrations occurred early on in the time series| before major reductions in nutrient availability. Correlation analysis revealed that this decline was associated with the re-appearance of Daphnia grazers. Further declines are only apparent in very recent years; correlation analysis and comparison of trends suggest that these were associated with the observed decline in nutrient concentrations. There was little correlation and no consistent relationship between annual measures of chlorophyll| and water temperature| but winter mean values did show a consistent positive relationship. Spring Daphnia densities showed an even stronger| and significant| positive relationship with spring water temperatures. It is clear from this that the scale of climate change predicted in the future will significantly alter the functioning of shallow lakes and seasonal patterns in water quality. This is a particular concern in Europe with the implementation of the EC Water Framework Directive| as if the net effect of global warming on annual measures of water quality is negative| the principle aim of 'good status' in all surface waters by 2016 will become even more difficult to achieve. 6258,2003,2,4,Changes in summer temperature and heat-related mortality since 1971 in North Carolina| South Finland| and Southeast England,Three climatically diverse regions were studied to determine the impact of temperature change on heat-related mortality from 1971 to 1997. Median regressions showed that May-August temperatures in North Carolina rose by 1.0degreesC (95% CL 0.0-2.0degreesC) from 23.5degreesC (74.3degreesF)| were unchanged in South Finland at 13.5degreesC (56.3degreesF)| and rose in Southeast England 2.1degreesC (0.3-4.0degreesC) from 14.9degreesC (58.8degreesF). After determining for each region the daily temperature (as a 3degreesC band) at which the mortality was the lowest| annual heat-related mortality was obtained as excess mortality per million at temperatures above this. Annual heat-related mortality per million (among the population at risk| aged 55+) fell in North Carolina by 212 (59-365) from 228 (140-317) to only 16 (not significant| NS); fell in South Finland by 282 (66-500) from 382 (257-507) to 99 (NS); and fell in Southeast England by 2.4 (NS) from 111 (41-180) to 108 (41-176). The falls in North Carolina and South Finland remained significant after allowances were made for changes in age| sex| and baseline mortality. Increased air conditioning probably explains the virtual disappearance of heat-related mortality in the hottest region| North Carolina| despite warmer summers. Other lifestyle changes associated with increasing prosperity probably explain the favorable trends in the cooler regions. (C) 2002 Elsevier Science (USA). All rights reserved. 6313,2003,2,4,Changes in the breeding biology of the Welcome Swallow (Hirundo tahitica) in New Zealand since colonisation,The Welcome Swallow was first recorded breeding in New Zealand in 1958| but is now common and widespread. Using nest record cards collected throughout New Zealand between 1962 and 1996 we investigated whether measures of breeding success showed temporal trends consistent with the effects of density dependence due to increased population densities. Controlling for potentially confounding factors| we found that: (i) breeding has occurred earlier in more recent years| (ii) nests in more recent years were more likely to produce fledglings| and (iii) there are no temporal trends in clutch size or the probability of at least one offspring failing to fledge. These results suggest that population densities have not yet reached the threshold at which density dependence limits breeding success. Earlier laying in more recent years is compatible with a response to global warming. As predicted for multiple-brooded species| clutch size exhibited a mid-season peak| the timing of which is consistent with the decline in the second half of the season being due to reduced foraging time. There was no evidence for a latitudinal gradient in clutch size within New Zealand. 6084,2003,2,4,Changes in the high-mountain vegetation of the central Iberian peninsula as a probable sign of global warming,Aerial images of the high summits of the Spanish Central Range reveal significant changes in vegetation over the period 1957 to 1991. These changes include the replacement of high-mountain grassland communities dominated by Festuca aragonensis| typical of the Cryoro-Mediterranean belt| by shrub patches of Juniperus communis ssp. alpina and Cytisus oromediterraneus from lower altitudes (Oro-Mediterranean belt). Climatic data indicate a shift towards warmer conditions in this mountainous region since the 1940s| with the shift being particularly marked from 1960. Changes include significantly higher minimum and maximum temperatures| fewer days with snow cover and a redistribution of monthly rainfall. Total yearly precipitation showed no significant variation. There were no marked changes in land use during the time frame considered| although there were minor changes in grazing species in the 19th century. It is hypothesized that the advance of woody species into higher altitudes is probably related to climate change| which could have acted in conjunction with discrete variations in landscape management. The pronounced changes observed in the plant communities of the area reflect the susceptibility of high-mountain Mediterranean species to environmental change. (C) 2003 Annals of Botany Company. 6142,2003,2,4,Changes in the rhizome system of bracken subjected to long-term experimental treatment,1. Bracken Pteridium aquilinum is a serious weed of upland and marginal land. Its extensive rhizome system and large carbohydrate reserves make control difficult. This paper reports the results of seven long-term experiments| established in four diverse UK locations| to test control and vegetation restoration treatments. 2. Samples were obtained from 580 rhizome pits between 1998 and 2000. Total dry mass per unit area (M | a measure of performance) and ratio of frond-bearing to total rhizome dry mass (R | a relative measure of investment in frond production) were measured. 3. The range of means for M in untreated bracken was 1.8-5.1 kg m(-2) | greater than that reported by others (1.2-3.0 kg m(-2) ). Measured values for R were 0.24-0.42| again differing from other reports (0.10-0.38)| probably due to our policy of avoiding advancing bracken fronts. 4. Randomization tests were used to check for non-independence of sampling units. They confirmed the general adequacy of the anova results; there was little detectable interference between plots. Two regions contained matching pairs of experiments| thus variation within region was tested and differences were found in one region. 5. Five bracken control treatments (cutting| herbicide application and combinations) were employed at all but one experiment. Cutting once or twice per year generally gave the best results| reducing M by c . 60% after less than or equal to 5 years. Some subtreatments designed mainly for vegetation restoration| notably surface disturbance| also affected M . 6. R was reduced by herbicide treatment| for example from 0.30 to 0.16. Such low values of R are typical of invading bracken and are thought to represent rejuvenated and invasive rhizomes. Follow-up treatments are needed in such situations. Despite large differences between untreated M at matching experiments on Cannock Chase (Staffordshire)| treatment effects were similar at both sites (cutting twice per year or cutting together with herbicide application were best). At Sourhope (Cheviot Hills) a different pattern of response was obtained| with cutting alone giving better results than treatments involving herbicide. 7. The ratio of rhizome to frond dry mass per unit area was 10 : 1 in good conditions for growth| but the proportionate size of rhizomes could be reduced in poor growing conditions such as wet summers. 8. Synthesis and applications . In order to develop a national control strategy the following must be considered: rhizome mass differs between sites and in response to control treatments; cutting twice per year is generally most effective; where cutting is impossible| herbicide treatment should be applied. Weather may affect rhizome mass| with wet years being detrimental. This raises the possibility that bracken may increase under the drier conditions that may occur with global warming. 2837,2003,4,4,Changes in tropospheric composition and air quality due to stratospheric ozone depletion,Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing air pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone due to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2)| the emission of volatile organic compounds and the abundance of water vapor| are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone concentration can have a significant impact on human health and the environment. Trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) are produced by the atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). TFA has been measured in rain| rivers| lakes| and oceans| the ultimate sink for these and related compounds. Significant anthropogenic sources of TFA other than degradation HCFCs and HFCs have been identified. Toxicity tests under field conditions indicate that the concentrations of TFA and CDFA currently produced by the atmospheric degradation of HFCs and HCFCs do not present a risk to human health and the environment. The impact of the interaction between ozone depletion and future climate change is complex and a significant area of current research. For air quality and tropospheric composition| a range of physical parameters such as temperature| cloudiness and atmospheric transport will modify the impact of UV-B. Changes in the chemical composition of the atmosphere including aerosols will also have an impact. For|example| tropospheric OH is the 'cleaning' agent of the troposphere. While increased UV-B increases the OH concentration| increases in concentration of gases like methane| carbon monoxide and volatile organic compounds will act as sinks for OH in troposphere and hence change air quality and chemical composition in the troposphere. Also| changes in the aerosol content of the atmosphere resulting from global climate change may affect ozone photolysis rate coefficients and hence reduce or increase tropospheric ozone concentrations. 6053,2003,2,4,Changing features of the climate and glaciers in China's monsoonal temperate glacier region,[ 1] Climatic data| ice core records| the tree ring index| and recorded glacier variations have been used to reconstruct a history of climatic and glacial changes in the monsoonal temperate glacier region of southwestern China during the last 400 years. The region's temperature has increased in a fluctuating manner during the twentieth century after two cold stages of the Little Ice Age ( seventeenth to nineteenth centuries)| with a corresponding retreat of most of the glaciers| against a background of global warming. Retreat rates accelerated after the 1980s. The few advancing glaciers that did exist have started to retreat in recent years. The amount| trend| and amplitude of variation of precipitation have differed in different parts of the region. The Dasuopu ice core| from the western part of the region| shows a decreasing trend in precipitation| the converse of the trend in temperature. In the eastern part of the region| however| a rising trend of rainfall has accompanied increasing temperatures as a result of the variable atmospheric circulations from different sources. The southwest monsoon| the principal controlling factor in the Chinese monsoonal temperate glacier region| can be classified into the Indian monsoon and the Bengal monsoon. The former passes across the Indian Peninsula from the Arabian Sea and transports vapor for precipitation in the western part of the monsoonal temperate glacier region. The Bengal monsoon| originating in the Bay of Bengal| is the major source of precipitation in the eastern part of the region. The eastern part is also influenced by the southeast monsoon arriving from the western Pacific| and the western part is affected in winter by the southern branch of the westerly circulation. This complex atmospheric situation results in differing patterns of precipitation in the western and eastern zones. Although it is clear that both temperature and precipitation affect the glaciers| further work is needed to confirm which of these is the major factor influencing present glacier change. 6012,2003,2,2,Changing heat-related mortality in the United States,Heat is the primary weather-related cause of death in the United States. Increasing heat and humidity| at least partially related to anthropogenic climate change| suggest that a long-term increase in heat-related mortality could occur. We calculated the annual excess mortality on days when apparent temperatures-an index that combines air temperature and humidity-exceeded a threshold value for 28 major metropolitan areas in the United States from 1964 through 1998. Heat-related mortality rates declined significantly over time in 19 of the 28 cities. For the 28-city average| there were 41.0 +/- 4.8 (mean +/- SE) excess heat-related deaths per year (per standard million) in the 1960s and 1970s| 17.3 +/- 2.7 in the 1980s| and 10.5 +/- 2.0 in the 1990s. In the 1960s and 1970s| almost all study cities exhibited mortality significantly above normal on days with high apparent temperatures. During the 1980s| many cities| particularly those in the typically hot and humid southern United States| experienced no excess mortality. In the 1990s| this effect spread northward across interior cities. This systematic desensitization of the metropolitan populace to high heat and humidity over time can be attributed to a suite of technologic| infrastructural| and biophysical adaptations| including increased availability of air conditioning. 6307,2003,4,4,Chemistry of forest fires and regional haze with emphasis on Southeast Asia,The current state of knowledge regarding the chemistry of forest fires and regional haze is reviewed. More than 100 compounds have been identified in wood smoke and many of these have also been observed in field studies. Products of biomass combustion can have different environmental effects: CO(2) and CH(4) may contribute to global warming| NO(x) and SO(2) could contribute to rainwater acidity| whereas smoke particles and polynuclear aromatic hydrocarbons (PAHs) could affect human health. Also| photochemical reactions of primary emissions from biomass fires can lead to the production of secondary pollutants such as O(3). Regional haze episodes caused by forest fires have occurred in SE Asia on several occasions during the 1990s and the reported studies of these episodes are reviewed. Only total suspended particles (TSP) were determined in the earlier studies| and more comprehensive chemical investigations have only emerged during the more recent episodes| notably those of 1997 and 1998. To date| most of the measurements have centred on criteria pollutants (SO(2)| NO(2)| CO| O(3) and PM(10))| however| other pollutants (e.g.| VOCs| PAHs) have also been determined in certain studies. Rainwater analyses suggest that forest fires do not have a major acidifying effect because dissolved acidic gases (e.g.| SO(2)) are neutralised by alkaline substances (e.g.| Ca| Mg| K) that are also emitted by forest fires. There is a need for further laboratory and field studies in order to investigate important pollutant transformation mechanisms. 2715,2003,5,4,Chemostratigraphic evidence of Deccan volcanism from the marine osmium isotope record,Continental flood basalt (CFB) volcanism is hypothesized to have played a causative role in global climate change and mass extinctions. Uncertainties associated with radiometric dating preclude a clear chronological assessment of the environmental consequences of CFB volcanism. Our results document a 25% decline in the marine Os-187/Os-188 record that predates the Cretaceous-Tertiary boundary (KTB) and coincides with late Maastrichtian warming. We argue that this decline provides a chemostratigraphic marker of Deccan volcanism and thus constitutes compelling evidence that the main environmental consequence of Deccan volcanism was a transient global warming event of 3degrees to 5degreesC that is fully resolved from the KTB mass extinction. 2800,2003,2,4,Climate change and amphibian declines: is there a link?,Global climates have been changing| sometimes rapidly and dramatically| throughout the evolutionary history of amphibians. Therefore| existing amphibian species have been derived from those that have survived major climatic disturbances. Although recent global climate change has resulted in warming in many regions| temperatures in some areas to date have not changed measurably| or have even cooled. Declines of some amphibian populations have been correlated with climate events| but demonstrations of direct causal relationships need further research. Data are available indicating some indirect effect of climate change on the initiation of breeding activities of some amphibians that occur earlier than in previous springs| but the costs and benefits of these changes are just beginning to be investigated. Climate may also play an indirect role in facilitating epidemics of infectious disease. Regardless of the role that climate changes may have played in past and current amphibian declines| future shifts in climate| should they prove as dramatic as predicted| will certainly pose challenges for surviving amphibian populations and for successful recovery efforts of species that have suffered declines. 6191,2003,4,4,Climate change and sea turtles: a 150-year reconstruction of incubation temperatures at a major marine turtle rookery,Sea turtles show temperature dependent sex determination. Using an empirical relationship between sand and air temperature| we reconstructed the nest temperatures since 1855 at Ascension Island| a major green turtle (Chelonia mydas ) rookery. Our results show that inter-beach thermal variations| previously ascribed to the albedo of the sand| which varies hugely from one beach to another| have persisted for the last century. Reconstructed nest temperatures varied by only 0.5 degreesC on individual beaches over the course of the nesting season| while the temperature difference between two key nesting beaches was always around 3 degreesC. Hence inter-beach thermal variations are the main factor causing a large range of incubation temperatures at this rookery. There was a general warming trend for nests| with a mean increase in reconstructed nest temperatures for different months of between 0.36 and 0.49 degreesC for the last 100 years. 2814,2003,2,4,Climate change and the potential distribution of an invasive alien plant: Acacia nilotica ssp indica in Australia,1. Acacia nilotica is a spinescent woody legume that has become highly invasive in several parts of the world| including Australia where it has been declared a weed of national significance. Understanding the likely potential distribution of this notorious plant under current and future climate scenarios will enable policy makers and land managers to prepare appropriate strategies to manage the invasion. 2. CLIMEX was used to synthesize available information from diverse sources to model the invasion potential of A. nilotica and gain insights into the climatic factors limiting its range expansion. The model identified areas at risk of further invasion so that early preventative or ameliorative measures could be undertaken in a timely manner. 3. The potential distribution of A. nilotica in Australia under current climatic conditions is vast| and far greater than the current distribution. 4. Global climate change is likely to increase markedly the potential distribution of A. nilotica in Australia| significantly increasing the area at risk of invasion. The factors of most importance are the expected increases in water-use efficiency of A. nilotica due to increased atmospheric CO2 concentrations| allowing it to invade more xeric sites further inland| and increased temperatures| allowing it to complete its reproductive life cycle further southward (poleward). 5. Synthesis and applications. Simple paddock quarantine procedures may provide a means of limiting the range of A. nilotica within its potential distribution under current| as well as future| climate scenarios. The projected increased growth potential of A . nilotica throughout its current range suggests that if future management patterns result in seed pods lying unconsumed on the ground| heightened vigilance may be required to identify and eradicate new invasion foci arising from flood dispersal. The increased growth potential may also result in an alteration of the economic balance| in favour of harvesting A. nilotica for agroforestry or local bioenergy projects. A crucial component in containing this invasion will be raising public awareness of the invasion threat posed by A. nilotica| its identification and suitable control techniques. 2818,2003,2,4,Climate change and the skiing industry in southern Ontario (Canada): exploring the importance of snowmaking as a technical adaptation,The winter tourism industry has been repeatedly identified as potentially vulnerable to global climate change. Climate change impact assessments of ski areas in Australia| Europe and North America all project negative consequences for the industry. An important limitation of earlier studies has been the incomplete consideration of snowmaking as a climate adaptation strategy. Recognising that snowmaking is an integral component of the ski industry| this study examined how current and improved snowmaking capacity affects the vulnerability of the ski industry in southern Ontario (Canada) to climate variability and change. A 17 yr record of daily snow conditions and operations from a primary ski area in the region was used to calibrate a ski season simulation model that included a snowmaking module with climatic thresholds and operational decision rules based on interviews with ski area managers. Climate change scenarios (2020s| 2050s| 2080s) were developed by downscaling climate variables from 4 general circulation models (using both IS92a and SIZES emission scenarios) with the LARS weather generator (parameterized to local climate stations) for input into a daily snow depth simulation model. In contrast to earlier studies| the results indicate that ski areas in the region could remain operational in a warmer climate| particularly within existing business planning and investment time horizons (into the 2020s)| The economic impact of additional snowmaking requirements remains an important uncertainty. Under climate change scenarios and current snowmaking technology| the average ski season at the case study ski area was projected to reduce by 0-16 % in the 2020s| 7-32 % in the 2050s and 11-50 % in the 2080s. Concurrent with the projected ski season losses| the estimated amount of snowmaking required increased by 36-144 % in the scenarios for the 2020s. Required snowmaking amounts increased by 48-187 % in the scenarios for the 2020s. The ability of individual ski areas to absorb additional snowmaking costs and remain economically viable in addition to the relative impact of climate change on other nearby ski regions (Quebec| Michigan and Vermont) remain important avenues of further research. The findings reveal the importance of examining a wide range of climate change scenarios and the necessity of including snowmaking and other adaptation strategies in future climate change vulnerability assessments of the ski industry and winter tourism in other regions of the world. 2742,2003,2,4,Climate change decreases aquatic ecosystem productivity of Lake Tanganyika| Africa,Although the effects of climate warming on the chemical and physical properties of lakes have been documented(1)| biotic and ecosystem-scale responses to climate change have been only estimated or predicted by manipulations and models(1). Here we present evidence that climate warming is diminishing productivity in Lake Tanganyika| East Africa. This lake has historically supported a highly productive pelagic fishery that currently provides 25-40% of the animal protein supply for the populations of the surrounding countries(2). In parallel with regional warming patterns since the beginning of the twentieth century| a rise in surface-water temperature has increased the stability of the water column. A regional decrease in wind velocity has contributed to reduced mixing| decreasing deep-water nutrient upwelling and entrainment into surface waters. Carbon isotope records in sediment cores suggest that primary productivity may have decreased by about 20%| implying a roughly 30% decrease in fish yields. Our study provides evidence that the impact of regional effects of global climate change on aquatic ecosystem functions and services can be larger than that of local anthropogenic activity or overfishing. 2730,2003,2,4,Climate change in Australian tropical rainforests: an impending environmental catastrophe,It is now widely accepted that global climate change is affecting many ecosystems around the globe and that its impact is increasing rapidly. Many studies predict that impacts will consist largely of shifts in latitudinal and altitudinal distributions. However| we demonstrate that the impacts of global climate change in the tropical rainforests of northeastern Australia have the potential to result in many extinctions. We develop bioclimatic models of spatial distribution for the regionally endemic rainforest vertebrates and use these models to predict the effects of climate warming on species distributions. Increasing temperature is predicted to result in significant reduction or complete loss of the core environment of all regionally endemic vertebrates. Extinction rates caused by the complete loss of core environments are likely to be severe| nonlinear| with losses increasing rapidly beyond an increase of 2 degreesC| and compounded by other climate-related impacts. Mountain ecosystems around the world| such as the Australian Wet Tropics bioregion| are very diverse| often with high levels of restricted endemism| and are therefore important areas of biodiversity. The results presented here suggest that these systems are severely threatened by climate change. 2802,2003,2,3,Climate change scenarios and the effect of sea-level rise for Estonia,Climate warming due to the enhanced greenhouse effect is expected to have a significant impact on natural environment and human activity in high latitudes. Mostly| it should have a positive effect on human activity. The main threats in Estonia that could be connected with sea-level rise are the flooding of coastal areas| erosion of sandy beaches and the destruction of harbour constructions. Possible climate change and its negative impacts in the coastal regions of Estonia are estimated in this paper. Climate change scenarios for Estonia were generated using a Model for the Assessment of Greenhouse-gas Induced Climate Change (MAGICC) and a regional climate change database-SCENanario GENerator (SCENGEN). Three alternative emission scenarios were combined with data from 14 general circulation model experiments. Climate change scenarios for the year 2100 indicate a significant increase in air temperature (by 2.3-4.5 degreesC) and precipitation (by 5-30%) in Estonia. The highest increase is expected to take place during winter and the lowest increase in summer. Due to a long coastline (3794 km) and extensive low-lying coastal areas| global climate change through sea-level rise will strongly affect the territory of Estonia. A number of valuable natural ecosystems will be in danger. These include both marine and terrestrial systems containing rare plant communities and suitable breeding places for birds. Most sandy beaches high in recreational value will disappear. However| isostatic land uplift and the location of coastal settlements at a distance from the present coastline reduce the rate of risk. Seven case study areas characterising all the shore types of Estonia have been selected for sea-level rise vulnerability and adaptation assessment. Results and estimates of vulnerability to 1.0-m sea-level rise by 2100 are presented in this paper. This is the maximum scenario according to which the actually estimated relative sea-level rise would vary from 0.9 m (SW Estonia) to 0.7 m on the north-western coast due to different velocities of land uplift in the studied areas. The longest coastline section recession (6.4 km) would occur on the western coast of the mainland where extensive areas of reed bed and flooded meadows would relocate landwards or disappear. Possible damages in Tallinn| the capital city| would be the greatest compared to the other study areas. The greatest threat to the environment of the Gulf of Finland and the whole Baltic Sea is the dumping site of the former uranium enrichment plant in Sillamae which is situated very close to the coastline and can be easily influenced during storms. (C) 2002 Elsevier Science B.V All rights reserved. 6128,2003,5,4,Climate during the Permian-Triassic biosphere reorganizations. Article 2. Climate of the Late Permian and Early Triassic: General inferences,The Late Permian-initial Triassic was a period of the Earth climate change| as the glacial climate of the Late Paleozoic was replaced by the non-glacial one of the Mesozoic. The intricate trend of this process is reconstructed and illustrated by schematic paleoclimatic maps. Warming in the second half of the Sakmarian Age resulted in a rapid degradation of huge glacial belt to the polar glacial cap. By the Kazanian Age| the latter was gradually replaced by the high-latitude temperate-cold belt with retained and new glacial centers that intermittently widened. In the Tatarian Age| a similar temperate-cold belt appeared in the Northern Hemisphere as well. The next strong and sudden global warming occurred in the Permian-Triassic boundary period when the temperate-warm climate developed in high latitudes of the Northern Hemisphere and temperate one in the Southern Hemisphere. General warming complicated by frequent different-rank oscillations transformed the climatic zoning on the Earth and resulted in rapid global ecological changes. Huge dimensions of Pangea and mountainous belts and ridges at its margins primordially determined wide development of the semiarid and and climate in low latitudes. During the Late Permian-initial Triassic period| the aridity of the Earth was increasing that is evident from successive widening of and and semiarid belts of Pangea| which advanced toward middle latitudes| and from grown aridity in the equatorial mountainous belt and in tropical latitudes of the Tethys. Global warming was main factor responsible for stepwise widening of and and semiarid belts. Another cause of aridity increase was gradual regression of inner seas. Arid and semiarid belts occupied about 40% of land at the beginning of the Early Permian| 55% in the late Sakmarian-early Artinskian time| and 80% in the Induan Age. Paleoclimatic reconstructions confirm the assumed significance of monsoons impact on the climate development in the Permian and Early Triassic to a certain extent only. During glacial periods| the climatic asymmetry of the Earth was particularly remarkable. Registered environmental changes of the Permian time (regressions| aridity growth| land elevation| orogeny| and island-arc volcanism) could result only in cooling. Warming of terminal Permian-Early Triassic| as well as C| O| S| and Sr isotopic anomalies were probably the first results of the main Pfalzian phase of the Hercynian tectogenesis with associated weakening of suprasubduction volcanism| intense regional metamorphism| and denudation of carbonaceous sedimentary sequences of orogens. The subsequent outburst of mantle volcanism| in particular| trap eruptions in Siberia promoted these processes further. Depending on their scale| climatic changes prepared or even provoked biotic crises| the mass extinctions included. 6224,2003,4,4,Climate oscillations and changes over Russia,Refined definitions of a climate| climatic variables| climate variability| climate changes| and climate monitoring that are applicable to the analysis of climate variability from observations in the case of a changing climate are given. The main features of global warming| are described. New data are reported on the features of climate changes over Russia in the second half of the 20th century and on changes in climate anomaly and extremeness. Empirical estimates for the local sensitivity of air temperature to changes in the greenhouse gas concentration are discussed. The estimates can be used to assess the expected temperature changes in the comin- 20-25 years. 2827,2003,3,4,Climate policy in light of climate science: The ICLIPS project,The paper introduces the Tolerable Windows Approach (TWA) as a decision analytical framework for addressing global climate change. It is implemented as an integrated assessment model (IAM) developed in the project on Integrated Assessment of Climate Protection Strategies (ICLIPS). The background and the main objectives of the project are described and its relationships to other current integrated assessment efforts are elucidated. Key features of the TWA are compared with those of cost-benefit and cost-effectiveness frameworks. An overview of the ICLIPS IAM framework is provided together with its methodological foundations. Main features of the individual models are presented| covering the climate| the aggregated economic| and the impact models. Additional components of the framework include dynamic mitigation cost functions and an agriculture/land-use model (both incorporated into the fully integrated ICLIPS climate-economy model) as well as a global multi-region| multi-sector| dynamic general equilibrium model. 2826,2003,4,4,Climate system modeling in the framework of the tolerable windows approach: The ICLIPS climate model,The computational burden associated with applications of the Tolerable Windows Approach (TWA) considerably exceeds that of traditional integrated assessments of global climate change. As part of the ICLIPS (Integrated Assessment of Climate Protection Strategies) project| a computationally efficient climate model has been developed that can be included in integrated assessment models of any kind. The ICLIPS climate model (ICM) is implemented in GAMS. It is driven by anthropogenic emissions of CO2| CH4| N2O| halocarbons| S(F)6| and SO2. The output includes transient patterns of near-surface air temperature| total column-integrated cloud cover fraction| precipitation| humidity| and global mean sea-level rise. The carbon cycle module explicitly treats the nonlinear sea water carbon chemistry and the nonlinear CO2 fertilized biosphere uptake. Patterns of the impact-relevant climate variables are derived form empirical orthogonal function (EOF) analysis and scaled by the principal component of temperature change. The evolution of the latter is derived from a box-model-type differential analogue to its impulse response function convolution integral. We present a description of the ICM components and some results to demonstrate the model's applicability in the TWA setting. 6000,2003,2,4,Climate-related changes in recruitment of the bivalve Macoma balthica,Population dynamics of common intertidal bivalves (Cerastoderma edule| Macoma balthica| Mya arenaria| Mytilus edulis) are strongly related to seawater temperatures. In northwestern European estuaries| series of mild winters followed by low bivalve recruit densities lead to small adult stocks. In this study| we examine temperature-induced effects on reproductive output (eggs m(-2))| onset of spawning (day of the year)| and the juvenile instantaneous mortality rate (per day) of M. balthica. Data analysis was based on an extensive long-term data set (1973-2001) originating from the western Wadden Sea. Our results strongly suggest that rising seawater temperatures affect recruitment by a decrease in reproductive output and by spring advancement of bivalve spawning. Apparently| global warming upsets the evolved reproductive strategy of this marine bivalve to tune its reproduction to the most optimal environmental conditions for the first vulnerable life stages| most importantly the match/mismatch of time of spawning with that of the phytoplankton bloom and the settlement of juvenile shrimps on the tidal flats. It is hypothesized that the observed density-dependent mortality of juvenile bivalves may act via competition for food| a behavioral response of shrimp to low spat densities| or be the result of the response of age and size at metamorphosis of marine bivalves to resource variability. It is to be expected that prolonged periods of lowered bivalve recruitment and stocks will lead to a reformulation of estuarine food webs and possibly a reduction of the resilience of the system to additional disturbances| such as the depletion and disturbance by shellfish fisheries. 6243,2003,2,3,Climatic change and river ice breakup,The flow hydrograph| thickness of the winter ice cover| and stream morphology are three climate-influenced factors that govern river ice processes in general and ice. breakup and jamming in particular. Considerable warming and changes in precipitation patterns| as predicted by general circulation models (GCMs) for various increased greenhouse-gas scenarios| would affect the length and duration of the ice season and the timing and severity of ice breakup. Climate-induced changes to river ice processes and the associated hydrologic regimes can produce physical| biological| and socioeconomic effects. Current knowledge of climatic impacts on the ice breakup regime of rivers and the future effects of a changing climate are discussed. 6175,2003,2,4,Climatic factors and increased frequencies of 'southern' chromosome forms in natural populations of Drosophila robusta,New data are reported from two localities where historical changes in the relative frequencies of the gene arrangements of the woods fly| Drosophila robusta| had been documented earlier and from two localities that had last been sampled over 30 years ago. Several arrangements were found to have increased frequencies in all the localities studied. These arrangements are the ones with corresponding north-south clines| most also with corresponding relations to altitude. This. plus the fact that the similar changes have occurred in four states| one very far from the others| indicates that natural selection related to a pervasive climate effect| such as global warming| is responsible. Significant changes in another arrangement| one with no regular north-south or altitudinal variability| in some of the localities probably involve different ecological factors. 2815,2003,2,4,Climatic influences on riverine nitrate flux: Implications for coastal marine eutrophication and hypoxia,The average nitrate flux of the lower Mississippi River increased 3.3-fold between 1954-1967 and 1983-2000. During the same time period| the average nitrate concentration increased 2.3-fold while the average discharge increased 40%. Partitioning of the observed trend in nitrate flux among the two flux components| nitrate concentration and discharge| revealed that about 80% of the observed increase in flux could be explained by the increase in nitrate concentration. This indicates that a historical increase in the anthropogenic nutrient inputs has had a far greater impact on the lower Mississippi River nitrate flux than a change in climate. The influence of climatic factors on nitrate flux has been significant and may further increase as a result of global climate change. This argument is supported by two tines of evidence. The residual component of nitrate flux| obtained by removing a trend from the time series| is controlled primarily by the variability in discharge| i.e.| climatic factors. Also| there is a highly significant relationship between discharge and nitrate concentration at the low end of the discharge spectrum (< 13|000 m(3) s(-1)). The differences in nitrate flux between flood and drought years are significantly larger than the variations in discharge. This makes the Mississippi River nitrate flux potentially sensitive to future changes in the frequency of extreme climatic events. Because of the importance of nitrate for the productivity of coastal phytoplankton| future climate change would likely have important implications for coastal marine eutrophication and hypoxia. 6042,2003,2,4,Climatic warming and accompanying changes in the ecological regime of the Black Sea during 1990s,[1] The Black Sea ecosystem is shown to experience abrupt shifts in its all trophic levels from primary producers to apex predators in 1995 - 1996. It arises as a manifestation of concurrent changes in its physical climate introduced by intensive warming of its surface waters as well as abrupt increases in the mean sea level and the net annual mean fresh water flux. The warming is evident in the annual-mean sea surface temperature ( SST) data by a continuous rise at a rate of similar to0.25 degreesC per year| following a strong cooling phase in 1991 - 1993. The most intense warming event with similar to2 degreesC increase in the SST took place during winters of the 1994 - 1996 period. It also coincides with 4 cm yr(-1) net sea level rise in the basin| and substantial change in the annual mean net fresh water flux from 150 km(3) yr(-1) in 1993 to 420 km(3) yr(-1) in 1997. The subsurface signature of warming is marked by a gradual depletion of the Cold Intermediate Layer ( characterized by T < 8 &DEG;C) throughout the basin during the same period. Winters of the warming phase are characterized by weaker vertical turbulent mixing and upwelling velocity| stronger stratification and| subsequently| reduced upward nutrient supply from the nutricline. From 1996 onward| the major late winter-early spring peak of the classical annual phytoplankton biomass structure observed prior to mid- 90s was| therefore| either weakened or disappeared altogether depending on local meteorological and oceanographic conditions during each of these years. The effect of bottom-up limited unfavorable phytoplankton growth is reflected at higher trophic levels (e.g.| mesozooplankton| gelatinous macrozooplankton| and pelagic fishes) in the form of their reduced stocks after 1995. 6048,2003,3,3,CO2 mitigation technologies in the steel industry: a benchmarking study based on process calculations,Global warming presents an enormous challenge to the steel industry| which is both carbon-intensive and energy efficient. Lean production can provide some short-term emission mitigation| at the level of the Kyoto requirements. In the middle term| more use of scrap will also help alleviate emissions. But to reach much larger reductions in GHG emissions| on a par with the likely targets that will be set after the Kyoto period| the steel industry will have to imagine new production paradigms| which constitutes its most formidable challenge for the years to come. Carbon capture and sequestration| processes leaner in carbon use| electricity and hydrogen from green sources will have to be added together in a patchwork of process routes| which will have to be developed at great risk in the next decade| hopefully through broad international cooperation. 6320,2003,3,2,Coalbed methane extraction and utilization,Coalbed methane (CBM) is the generic name for all methane of coal seam origin. It is a natural gas formed by geological| or biological| processes in coal seams and generally consists predominantly of methane| but may also contain some higher alkanes and non-combustible gases. Methane is released whenever coal is de-stressed or fractured by mining. Methane is one of the main greenhouse gases contributing to global warming| therefore releasing it to atmosphere is an environmental hazard. However| it is also an important energy resource and can be recovered from operational coal mines| abandoned coal mines| and virgin (unmined) coal seams. Significant volumes of CBM are exploited worldwide for space heating| industrial processes| and power generation. This paper critically reviews the current UK and worldwide status of CBM extraction and utilization technologies building on a previous study funded through the Department of Trade and Industry's Cleaner Coal Technology Programme [1]. 2722,2003,5,4,Coherence resonance and ice ages,The processes and feedbacks responsible for the 100-kyr cycle of Late Pleistocene global climate change are still being debated. This paper presents a numerical model that integrates (1) long-wavelength outgoing radiation| (2) the ice-albedo feedback| and (3) lithospheric deflection within the simple conceptual framework of coherence resonance. Coherence resonance is a dynamical process that results in the amplification of internally generated variability at particular periods in a system with bistability and delay feedback. In the Late Pleistocene climate system| bistability results from a combination of long-wavelength outgoing radiation and the ice-albedo feedback. These processes are in equilibrium at interglacial and full-glacial conditions. Delay feedback results from the influence of lithospheric deflection on ice sheet advance and retreat. This process has commonly been represented in numerical climate models by complex models of ice sheet dynamics. As an alternative| the present model incorporates ice sheet dynamics implicitly by using the observed relationship between ice coverage and global temperature. The result is a simple| well-constrained model for the Late Pleistocene global climate system with only one free parameter. The model accurately reproduces the climate variability recorded in the Vostok ice core from timescales of several thousand to one million years| including the histograms and power-spectral behavior of the data. The 100-kyr cycle is a free oscillation in the model| present even in the absence of external forcing. The model also reproduces smaller-amplitude periodicities at odd harmonics of 100 kyr| suggesting that a significant portion of the spectral power at the Milankovitch bands of 41 and 29 kyr may be internally generated. Finally| the development of 100-kyr oscillations in the Mid-Pleistocene may be understood within this model framework as the transition from a climate with one stable state to a system with two stable states brought about by the development of large continental ice sheets and the addition of the ice-albedo feedback to the climate system. 6214,2003,2,4,Common themes in changing vector-borne disease scenarios,The impact of climate change on disease patterns is controversial. However| global burden of disease studies suggest that infectious diseases will contribute a proportionately smaller burden of disease over the next 2 decades as non-communicable diseases emerge as public health problems. However| infectious diseases contribute proportionately more in the poorest quintile of the population. Notwithstanding the different views of the impact of global warming on vector-borne infections this paper reviews the conditions which drive the changing epidemiology of these infections and suggests that such change is linked by common themes including interactions of generalist vectors and reservoir hosts at interfaces with humans| reduced biodiversity associated with anthropogenic environmental changes| increases in Plasmodium falciparum:P. vivax ratios and well-described land use changes such as hydrological| urbanization| agricultural| mining and forest-associated impacts (extractive activities| road building| deforestation and migration) which are seen on a global scale. 6207,2003,3,2,Comparative analysis between biomass and topographic features in an arid land| Western Australia,Global warming is a serious problem requiring immediate countermeasures. Large-scale afforestation in and areas for the aim of absorbing CO2 is considered to be one of these measures and the research activities for it have been carried out in Leonora| Western Australia. In this study| the relationship between the biomass distribution and topographic features was examined in order to collect basic information for the selection of suitable afforestation regions in the research area using a biomass distribution map and some topographic elements. The results were as follows. (1) Plant growth is related to the movement of and the volume of runoff water derived from inequality of the ground| which leads to a biased distribution of nutrient accumulation and of surface soil thickness. (2) The total potential biomass estimated from the present topography is greater than the present biomass in the 30 km x 50 km research area. A mass of 319 kt-C could be absorbed in the research area without any improvements in the landform. (3) A substantial improvement on the environment utilizing vast and areas by afforestation is necessary to fix enough carbon deterring global warming. 6041,2003,3,3,Comparison of CO2 fixation in wood used for residence houses in Japan and Korea,In this study| we have estimated the amount of carbon (C) fixation in wooden materials used for residence house units in Japan and Korea. This type of C fixation might be helpful to prevent the global warming. In year 2000| the amount of C fixation in the wooden materials was approximately 7.3% (150 million C ton) of total forest C accumulation in Japan| whereas in Korea| it was 2.0% (4.3 million C ton) of the total forest C accumulation. The reason is that structural types of the house units on wood utilization in Japan and Korea are clearly different. Japanese have used 90% of wooden materials for their residence houses but Korean house units have built mostly using non-wooden materials such as concrete| bricks| and stones. It has resulted that the number of total houses in Japan is 5 times higher than that in Korea| whereas the amount of C fixed by the wood materials in Japanese house units is 35 times higher than in Korean's. Therefore| to improve C fixation| it might be necessary to increase wooden residence houses and use of the wooden interior or exterior materials in the residence houses| especially in Korea. 6301,2003,3,3,Comparison of the environmental damage caused by vehicles with different alternative fuels and drivetrains in a Brussels context,A comprehensive methodology has been developed to compare the environmental damage caused by vehicles with different alternative fuels| such as CNG| LPG| etc.| and drivetrains| such as electric and hybrid drives. This paper describes how the environmental effect of vehicles should be defined and includes parameters concerning vehicle emissions and their influence on human well-being and the environment. It then describes how the environmental effect of vehicles could be defined| taking into account the availability of accurate and reliable data. Rating systems are analysed as a means of comparing the environmental effect of vehicles| allowing decision-makers to dedicate their financial and non-financial policies and measures as a function of the ecological damage. Different types of pollution (acid rain| photochemical air pollution| noise pollution| etc.) and their effect on numerous receptors such as ecosystems| buildings and human beings (e.g. cancer| respiratory diseases| etc.) and global warming are considered. The methodology described| known as Ecoscore| is based on a methodology similar to life cycle assessment (LCA) which considers the part played by emissions in certain types of damage (e.g. by using the exposure-response damage function). Total emissions involve oil extraction| transport and refinery. fuel distribution and electricity generation and distribution (well-to-wheel approach). Emissions due to the production| use and dismantling of the vehicle (cradle-to-grave approach) should also be considered. The different types of damage are normalized to make comparisons possible. Hence. a reference value (determined by a chosen reference vehicle) will be defined as a target value (the normalized value will thus measure a kind of distance to target). The contribution of the different normalized types of damage to a single value-Ecoscore-is based on a panel weighting method. This new approach differs from other methodologies in that it has been especially developed for the assessment of the environmental effect of vehicle emissions in an urban context| such as the Brussels Capital Region. Additionally| this methodology not only considers conventional vehicles but can also evaluate all alternative fuels and drivetrains with new vehicle technologies. Some examples of Ecoscore calculation are illustrated. 2757,2003,4,4,Complex methodological approach to the studies of natural microlayers at the air/water interface,The investigations of sea-surface microlayers are crucial for better understanding of the mechanisms and physicochemical processes at natural phase boundaries which play an important role in the marine environmental protection and global climate change. Sea-surface microlayers were studied in an original sample without any pretreatment and as ex-situ reconstructed films after previous extraction of the sample by organic solvents of different polarity. For physicochemical characterization of natural and ex-situ reconstructed sea-surface microlayer samples a complex methodological approach was applied. Monolayer techniques| Brewster angle microscopy| reflection spectroscopy and electrochemical methods were used. Samples were collected from a Middle Adriatic eutrophicated sea-lake. Results were compared and discussed with respect to previously reported results obtained by analysing the samples from the same area and from the Northern Adriatic. (C) 2003 Elsevier Science B.V. All rights reserved. 6036,2003,2,4,Composition| temporal changes and ecological guild classification of the ichthyofaunas of large European estuaries - a comparison between the Tagus (Portugal) and the Elbe (Germany),Fish species densities from 1025 hauls obtained with beam trawl and stow net catches from the southern Tagus and northern Elbe estuaries were analysed for two different periods of time between 1978 and 1997. The data were related with environmental factors to compare species composition and densities| contributions of different ecological guilds| structuring environmental key factors| intra-annual cyclicity and interperiodical stability of ichthyofaunas in large European estuaries at different latitudes. Although the total number of species in both the Tagus and Elbe estuaries ( Tagus: 57 species| Elbe: 58 species) was very similar| significant differences were estimated in species compositions| species densities and number of species| and individuals of the different ecological guilds between both estuaries. A total of 15 species occurred in both estuaries but only two of these species| the catadromous Anguilla anguilla and the marine estuarine opportunist Pleuronectes flesus| contributed substantially to the total abundance. Marine species together contributed more than 5% of the total number of species in the Tagus and Elbe estuaries| whereas their contribution in number of individuals amounted to 22% in the Tagus and only 9% in the Elbe. In terms of number of individuals| the ichthyofauna of the Tagus estuary was dominated by estuarine species ( especially Pomatoschistus spp.) contributing 68% of the total abundance. In contrast| the fish fauna of the Elbe estuary was dominated by high numbers of anadromous species (88%) individuals| especially Osmerus eperlanus. Canonical corresponding analyses (CCA) indicated that| besides intra-annual variables| salinity and mouth distance were two of the most important environmental factors structuring the fish communities in both estuaries. Moreover| water depth was found to be an important environmental factor in the Tagus estuary| whereas the water temperature substantially affected the ichthyofaunal composition in the Elbe estuary. In both estuaries| contributions by number of species and number of individuals of the different ecological guilds were not statistically different between the two periods considered| 1978 - 80 and 1995 - 97 for the Tagus| and 1981 - 86 and 1989 - 95 for the Elbe. Nevertheless| from 1981 - 86 until 1989 - 95 a remarkable increase of about 4.5 times in the densities of O. eperlanus was observed in the Elbe estuary| probably related to improved water quality| especially of oxygen conditions in the nurseries since 1990. This was also supported by the results of CCA| suggesting important influences of the years 1989 and 1990 on the Elbe estuary fish assemblage. Climate change as a result of global warming may be evident for the observed changes of the densities of P. flesus which decreased in the southern Tagus estuary and| in contrast| increased in the northern Elbe estuary during comparable periods of time. It is recommended to use the ecological guild classification scheme which was applied for the Tagus and Elbe estuaries for further studies of European estuarine fish assemblages. 2835,2003,2,4,Consequences of climate-induced salinity increases on zooplankton abundance and diversity in coastal lakes,Intermittent saline intrusions are a common feature of many coastal lakes and wetlands. These ecosystems are often important sites of biodiversity| biological productivity| and ecosystem services such as the removal of sediment| nutrients| and contaminants from inflowing rivers. Predicted effects of global climate change| including sea level rise| are likely to intensify saline intrusions into such ecosystems. Analyses of taxonomic diversity and abundance of zooplankton at different salinities in Lake Waihola| South Island| New Zealand| are supported by results of laboratory studies of salinity tolerances of 3 crustacean taxa Gladioferens pectinatus| Boeckella hamata and Daphnia carinata obtained from the lake. The field and laboratory analyses show that severe perturbations of zooplankton community structure and abundance are caused by even minor saline intrusions into Lake Waihola that raise the salinity to >1.2 psu. Our analyses of Lake Waihola| and data from brackish ecosystems around the world| show that even relatively small increases in salinity levels can drive such systems to a state of depleted biodiversity and abundance| altering ecosystem functioning. 2839,2003,2,4,Consequences of manipulations in carbon and nitrogen supply for concentration of anti-herbivore defence compounds in Salix polaris,The concentration of carbon-based anti-herbivore defence compounds is key to herbivore utilization of forage. Production of phenolics and condensed tannins in boreal woody plants is known to reduce grazing pressure. Their production depends| among other things| on the availability of nutrient resources| especially nitrogen| relative to the availability of assimilates. The carbon-nutrient balance (CNB) hypothesis (Bryant| Chapin & Klein| 1983) predicts a decrease in the concentration of carbon-based defence compounds with increased availability of nutrients. In a High Arctic heath| I manipulated the carbon-nitrogen balance of polar willow (Salix polaris) in a factorial| multi-level fertilizing and shading experiment. Other plots were subject to elevated temperature. After 2 years| shading and| to a lesser extent| fertilization had caused an increase in nitrogen concentrations in the leaves| which were highly and negatively correlated with lower total phenolic and condensed tannin concentrations. Elevated temperature caused no such effects| but increased growth significantly| while shading reduced shoot biomass| and fertilization had no detectable effect. These results are consistent with the CNB hypothesis. On the basis of this study it seems unlikely| however| that environmental modifications due to global climate change will have a major impact on defence chemistry| as very high shading (>70%) and fertilization levels (>1.5 g m(-2) year(-1)) were needed to produce significant deviations from controls. 2838,2003,2,2,Conservation impact of climatic variability on pollination of the federally endangered plant| Clematis socialis (Ranunculaceae),Biotic pollination should be an important consideration when devising management plans for endangered plant species. In this study we documented inter-annual shifts in the suite of floral visitors to Clematis socialis| a federally endangered species. These pollinator shifts were correlated with shifts in climatic variables that we used as a proxy for the potential effects of climatic change. In addition| we characterized floral visitor behavior and conducted single-visit seed set experiments to assess the pollination effectiveness of floral visitors. Five insect species visited flowers of C. socialis: two lepidopteran species (Erynnis juvenalis and Hemaris diffinis) and three bee species (Anthophora ursina| Bombus pennsylvanicus and Xylocopa virginica). Due to their relatively greater frequency of flower visitation and high single-visit seed set (ca. 2.6-3 seeds/visit)| two bee species (Anthophora ursina and Bombus pennsylvanicus) are considered to be the major pollinators of C. socialis. However| the relative importance of each pollinator species varied between years. Anthophora ursina was the most important pollinator in 1997| a year when C. socialis bloomed later in the spring. Queens of Boinbus pennsylvanicus were the primary pollinator during 1996| a year when C. socialis bloomed relatively early in the spring. We conclude that management plans that focus on the "best pollinator" of a suite of pollinators may not preserve the long-term reproductive integrity of endangered plants with generalized pollination systems. We further conclude that asynchrony between flowering season and pollinator activity patterns may be a risk factor associated with human-caused global climate change. 6209,2003,3,2,Control of anthropogenic CH4 and N2O emissions from several industrial sources and from daily human life,Recently| the control of non-CO2 greenhouse gases has attracted interest as a way to prevent global warming. Several research studies on the development and assessment of technologies to control CH4 and N2O emissions by human activities are under way. In the wastewater treatment field| the development of anoxic/oxic processes and the introduction of bacteria that effectively prevent N2O emission have been studied. Moreover| it has been clarified that eco engineering technologies such as artificial wetlands and soil trench systems are very effective| especially in developing countries. As for landfill disposal| CH4 oxidation by cover soil and the use of CH4 gas as a source of energy have very effectively reduced the emission of CH4. In the combustion field| it was clarified that N2O emissions vary according to the structure of each combustor and its operational conditions. And research and development concerning combustors and their optimum operational conditions are under way. Concerning automobile sources| characteristics of N2O emission from gasoline fueled vehicles installed with a catalyst were examined. Three way catalysts and so on are now being developed. Chemical industries| especially adipic acid production are another non-negligible N2O source| and cracking process related countermeasures have been applied. CH4 and N2O emissions from agricultural land are strongly dependent on the oxidation-reduction environment of soil and on fertilization| so they must be suitably managed. The development and management of ruminants feeding and suitable treatment of animal waste are very important ways to control CH4 and N2O from livestock. Research projects to improve the CH4 and N2O emission-absorption inventory| and to estimate the suitable technologies to control CH4 and N2O emission are now in progress. Combining these projects appropriately will develop technologies and systems and will make great contributions to the control of the emission of GHGs and to global warming. 2721,2003,2,4,Control of behavioural strategies for capricious environments,In addition to seasonal changes in morphology| physiology and behaviour that occur in predictable annual cycles| there are facultative responses to unpredictable events known as labile (i.e. short-lived) perturbation factors. These rapid behavioural and physiological changes have been termed the 'emergency life-history stage' and serve to enhance lifetime fitness. There are four major components: (1) proactive/reactive coping styles for responding to psychosocial stress| predation| and so forth; (2) fight-or-flight responses to rapid emergencies such as an attack by a predator or sudden severe storm; (3) 'take-it-or-leave-it' behavioural and physiological responses to longer-term perturbations of the physical environment; and (4) sickness behaviour and fever designed to respond to infection. Glucocorticosteroids interact with cytokines and with other hormones in the hypothalamo-pituitary-adrenal cascade and in the autonomic nervous system to initiate and orchestrate the emergency life-history stage within minutes to hours. Some traits of the emergency life-history stage include: redirection of behaviour from a normal life-history stage to increased foraging| irruptive-type migration during the day| enhanced restfulness at night| elevated gluconeogenesis| and recovery once the perturbation passes. These physiological and behavioural changes allow an individual to avoid potential deleterious effects of stress that may result from chronically elevated levels of circulating glucocorticosteroids over days and weeks. Thus| acute rises in glucocorticosteroids following perturbations of the environment may serve primarily as 'antistress' hormones| potentially allowing individuals to avoid chronic stress. Several field studies in diverse habitats indicate that individuals in free-living populations show elevated circulating levels of corticosteroids when they are in an emergency life-history stage. Some simple models based on food availability| body condition| social status and life-history stage| may allow predictions of sensitivity of the hypothalamopituitary-adrenal axis to labile perturbation factors. Although there is now extensive evidence for behavioural components of the emergency life-history stage in birds| there remains much to be learned about how other vertebrate groups| especially fish| cope with perturbations of the environment. Because of the unpredictable nature of these perturbations| systematic study of behavioural responses to them is not possible and investigators need to be 'opportunistic'. There is also a growing need to expand our knowledge of these phenomena because human disturbance| global climate change and pollution are all major perturbations of the environment. How vertebrates respond to the unpredictable in general will thus have important conservation value for the future. (C) 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. 6298,2003,4,3,Conversion of the nitrate nitrogen and nitrogen dioxide to nitrous oxides in plants,Tobacco and wheat are known to emit nitrous oxide (N2O). Provided that N2O is a greenhouse gas about 300 times worse than carbon dioxide in its potential for global warming| it is an intriguing and important subject| whether this activity is commonly present in other plants. In this study| 17 plant taxa that had been cultured aseptically were fed with N-15-labelled nitrate for one week (feeding period). The plant taxa were then transferred to a medium with non-labelled nitrate in gas-sealed pots and cultured for another week (emission period). The amount of labelled N2O emitted from the plants during the emission period was determined. This value reflects only a part of the capability of plants to convert nitrate to N2O| because the amount of N2O determined here does not correspond to the total N2O emission from plants| but to only an N-15-labelled N2O fraction emitted during the emission period from nitrate taken up into the plants during the feeding period. It was discovered that all of the 17 plant taxa analysed| except for Eucalyptus viminalis| showed emission of (N2O)-N-15. The emission ranged from 0.45 +/- 0.20 ng N2O/g fresh weight (kenaf) to -0.012 +/- 0.12 ng N2O/g fresh weight (Eucalyptus viminalis). This activity of converting nitrate to N2O is obviously common in plants with some exceptions. There was more than a 58-fold variation between the highest (Hibiscus cannabinus) and the second lowest (Nicotiana tabacum) capability to convert nitrate to N2O among the 17 plant taxa. The present result indicates that the potential of plants to convert nitrate to N2O highly varies among the plant species as in the case of the assimilation of nitrogen dioxide (N2O) where more than a 600-fold variation was observed among 217 plant taxa. A negative correlation was obtained for N2O emission and NO2 assimilation (r = 0.72). This is the first report where there was a competitive interaction between the assimilation and dissimilation activities in plants. It was also found that wild type and transgenic tobacco are able to convert NO2 to N2O when they were fumigated with N-15-labelled NO2. However since the N2O emission values observed in this study were approximately three orders of magnitude smaller than those observed with wheat leaves| the evaluation of the environmental significance of the N2O emission by plants must await quantitative analysis using the present system to figure out the full N2O emission capability of plants. 6174,2003,2,4,Coral delta O-18 records as an indicator of winter monsoon intensity in the South China Sea,We have used correlative analysis between mean December-January-February winter wind velocities| measured at the Xisha Meteorological Observatory (16degrees50'N| 112degrees20'E) in the middle of the South China Sea| and mean 518 0 data for the corresponding month from Porites lutea coral| collected in Longwan waters (19degrees20'N| 110degrees39'E)| to obtain a linear equation relating the two datasets. This winter wind velocity for the South China Sea (WMIIscs) can then be correlated to the coral delta(18)O by the equation WMIIscs = -1.213-1.351 delta(18)O (parts per thousand PDB)| r = -0.60| n = 40| P = 0.01. From this| the calculated WMIIscs-delta18O series from 1944 to 1997 tends to decrease during the 1940s to the 1960s; it increases slightly during the 1970s and then decreases again in the 1980s and 1990s. The calculated decadal mean WMIIscs-delta18O series had a obvious decrease from 5.92 to 4.63 m/s during the period of 1944-1997. The calculated yearly mean WMIIscs-delta18O value is 5.58 m/s from 1944 to 1976 and this decreases to 4.85 m/s from 1977 to 1998. That is the opposite trend to the observed yearly mean SST variation. The yearly mean SST anomaly is -0.27degrees from 1943 to 1976 and this increases to +0.16degrees from 1977 to 1998. Spectral analysis used on a 54-year-long calculated WMIIscs-delta18O series produces spectral peaks at 2.4-7 yr| which can be closely correlated with the quasibiennial oscillation band (QBO band| 2-2.4 yr) and the El Nino southern oscillation band (ENSO band| 3-8 yr). Hence most of the variability of the winter monsoon intensity in the middle of the South China Sea is mainly constrained by changes in the thermal difference between the land and the adjoining sea area| perhaps due to global warming. (C) 2003 Elsevier Science (USA). All rights reserved. 6006,2003,4,4,Correcting the orbit drift effect on AVHRR land surface skin temperature measurements,The orbital drift of the National Oceanic and Atmospheric Administration (NOAA)-7| -9| -11| -14 series of satellites results in a significant cooling effect on their afternoon path Advanced Very High Resolution Radiometer (AVHRR) land surface skin temperature (T-s) measurements. This effect mixes with the signal of true variations in the climate system| and thus prevents T-s from being directly used in climate change and global warming studies. This paper applies a physically based 'typical pattern technique' to remove the orbit drift effect from T-s. The technique utilizes a lookup table of representative land skin temperature diurnal cycles derived from the National Center for Atmospheric Research (NCAR) Climate Community Model (CCM3) coupled with the land surface model| Biosphere-Atmosphere Transfer Scheme (BATS). The generated typical patterns of T-s diurnal cycle are functions of vegetation type| season and latitude| and are combined with satellite observations to remove the cooling effect. Applying this methodology to eighteen years of AVHRR ( 1981-1998) T-s observations yields an improved skin temperature dataset. Analysis of the drift-corrected skin temperature illustrates a warming trend at the surface over the past two decades| a result which agrees well with the observed surface air temperature trend. A discussion of uncertainties in this technique is also presented. 6189,2003,2,4,Decline of North Atlantic eels: a fatal synergy?,Panmictic species pose particular problems for conservation because their welfare can be addressed effectively only on a global scale. We recently documented by means of microsatellite analysis that the European eel (Anguilla anguilla) is not panmictic but instead shows genetic isolation by distance. In this study| we extended the analysis to the American eel (A. rostrata) by applying identical analytical procedures and statistical power. Results obtained for the American eel were in sharp contrast with those obtained for the European eel: the null hypothesis of panmixia could not be rejected| and no isolation by distance was detected. This implies that the species must be managed as a single population. Using Bayesian statistics| we also found that the effective population sizes for both species were surprisingly low and that the populations had undergone severe contractions| most probably during the Wisconsinan glaciation. The apparent sensitivity of eels to climatic changes affecting the strength and position of the Gulf Stream 20 000 years ago is particularly worrying| given the effects of the ongoing global warming on the North Atlantic climate. Moreover| additional short-term stresses such as surging glass eel prizes| overfishing and lethal parasitic infections negatively affect eel population size. The fascinating transatlantic migration and life cycle of Atlantic eels is also their Achilles' heel as these negative short- and long-term effects will probably culminate in a fatal synergy if drastic conservation measures are not implemented to protect these international biological resources. 6253,2003,3,4,Decomposition of environmentally persistent trifluoroacetic acid to fluoride ions by a homogeneous photocatalyst in water,Decomposition of trifluoroacetic acid (TFA) was achieved with a tungstic heteropolyacid photocatalyst H3PW12O40. 6H(2)O in order to develop a technique for measures against TFA stationary sources. This is the first example of C-F bond cleavage in an environmentally harmful perfluoromethyl-group-containing compound using a homogeneous photocatalyst. The catalytic reaction proceeds in water at room temperature under UV-visible light irradiation in the presence of oxygen. The system produces only F- ions and CO2; the (mole of formed F-)/(mole of decomposed TFA) and (mole of formed CO2)/(mole of decomposed TFA) ratios were 2.91 and 2.09| respectively. GC/MS measurements showed no trace of other species such as environmentally undesirable CF4| which is the most stable perfluorocarbon and has a very high global warming potential. When the (initial T)/(initial catalyst) molar ratio was 20:1| the turnover number of TFA decomposition reached 5.58 by 72 h of irradiation| accompanying with no catalyst degradation. The catalytic reaction mechanism can be explained by a redox reaction between the catalyst and TFA| involving a photo-Kolbe process. 6091,2003,3,3,Deforestation control in Mato Grosso: A new model for slowing the loss of Brazil's Amazon Forest,Controlling deforestation in Brazil's Amazon region has long been illusive despite repeated efforts of government authorities to slow the process. From 1997 to 2000| deforestation rates in Brazil's 9-state "Legal Amazon" region continually crept upward. Now| a licensing and enforcement program for clearing by large farmers and ranchers in the state of Mato Grosso appears to be having an effect. The deforestation rate in Mato Grosso was already beginning to slacken before initiation of the program in 1999| but examination of county-level data suggests that deforestation in already heavily cleared areas was falling due to lack of suitable uncleared land| while little-cleared areas were experiencing rapid deforestation. Following initiation of the program| the clearing rates declined in the recent frontiers. Areas with greater enforcement effort also appear to have experienced greater declines. Demonstration of government ability to enforce regulations and influence trends is important to domestic and international debates regarding use of avoided deforestation to mitigate global warming. 6122,2003,2,4,Detection of environmental change in a marine ecosystem - evidence from the western English Channel,To separate human-induced changes from natural fluctuations in marine life requires long-term research. The western English Channel has been investigated from Plymouth for over 100 years. The abundance of marine life has been recorded and related to physical changes in the environment. By comparing different parts of the ecosystem we can demonstrate historic natural fluctuations| allowing prediction of effects of future global change. From the 1920s to the 1950s there was a period of warming of the sea| with increases in abundance of species of fish| plankton and intertidal organisms that are typically common in warmer waters to the south of Britain. After 1962 the sea cooled down and northern cold-water species became more abundant. Since the 1980s regional sea surface temperature has increased again and warm-water species are once more becoming abundant. (C) 2003 Elsevier Science B.V. All rights reserved. 6212,2003,2,2,Detection of human influence on sea-level pressure,Greenhouse gases and tropospheric sulphate aerosols-the main human influences on climate-have been shown to have had a detectable effect on surface air temperature(1-3)| the temperature of the free troposphere and stratosphere(2|4) and ocean temperature(5|6) Nevertheless| the question remains as to whether human influence is detectable in any variable other than temperature. Here we detect an influence of anthropogenic greenhouse gases and sulphate aerosols in observations of winter sea-level pressure (December to February)| using combined simulations from four climate models. We find increases in sea-level pressure over the subtropical North Atlantic Ocean| southern Europe and North Africa| and decreases in the polar regions and the North Pacific Ocean| in response to human influence. Our analysis also indicates that the climate models substantially underestimate the magnitude of the sea-level pressure response. This discrepancy suggests that the upward trend in the North Atlantic Oscillation index(7) (corresponding to strengthened westerlies in the North Atlantic region)| as simulated in a number of global warming scenarios(8-10)| may be too small| leading to an underestimation of the impacts of anthropogenic climate change on European climate. 6249,2003,2,4,Detection of intensification in global- and continental-scale hydrological cycles: Temporal scale of evaluation,Diagnostic studies of offline| global-scale Variable Infiltration Capacity (VIC) model simulations of terrestrial water budgets and simulations of the climate of the twenty-first century using the parallel climate model (PCM) are used to estimate the time required to detect plausible changes in precipitation (P)| evaporation (E)| and discharge (Q) if the global water cycle intensifies in response to global warming. Given the annual variability in these continental hydrological cycle components| several decades to perhaps more than a century of observations are needed to detect water cycle changes on the order of magnitude predicted by many global climate model studies simulating global warming scenarios. Global increases in precipitation| evaporation| and runoff of 0.6| 0.4| and 0.2 mm yr(-1) require approximately 30-45| 25-35| and 50-60 yr| respectively| to detect with high confidence. These conservative detection time estimates are based on statistical error criteria (alpha = 0.05| beta = 0.10) that are associated with high statistical confidence| 1 - alpha (accept hypothesis of intensification when true| i.e.| intensification is occurring)| and high statistical power| 1 - beta (reject hypothesis of intensification when false| i.e.| intensification is not occurring). If one is willing to accept a higher degree of risk in making a statistical error| the detection time estimates can be reduced substantially. Owing in part to greater variability| detection time of changes in continental P| E| and Q are longer than those for the globe. Similar calculations performed for three Global Energy and Water Experiment (GEWEX) basins reveal that minimum detection time for some of these basins may be longer than that for the corresponding continent as a whole| thereby calling into question the appropriateness of using continental-scale basins alone for rapid detection of changes in continental water cycles. A case is made for implementing networks of small-scale indicator basins| which collectively mimic the variability in continental P| E| and Q| to detect acceleration in the global water cycle. 2741,2003,2,4,Detection of large-scale climate signals in spring vegetation index (normalized difference vegetation index) over the Northern Hemisphere,Climate is one of the determinants driving ecosystems on both local and global scales. During the last two decades| there has occurred a dramatic temperature increase in the northern midlatitudes to high latitudes. The rapid warming has resulted in the promotion of bioactivity and an early growing season. However| the temperature and vegetation changes are not uniform in geographical distribution. In the present study| we analyze the spatial features in the normalized difference vegetation index (NDVI)-temperature relationship over Eurasia and North America in spring for the period 1982-2000. The NDVI data are derived from the Earth Observing System Pathfinder advanced very high resolution radiometer data sets. A singular value decomposition analysis is applied to the covariance matrix of the NDVI and temperature. Most of the squared covariance| 91.6%| is captured by the first seven paired modes. The result clearly indicates that the temperature is a focal factor influencing vegetation activity. Furthermore| those seven paired modes show large-scale features and well-defined patterns. The atmospheric circulation systems| such as the Southern Oscillation| North Atlantic Oscillation/Arctic Oscillation| Pacific/North American pattern| Eurasian pattern| western Pacific pattern| western Atlantic pattern| eastern Atlantic pattern| and North Pacific index| are found to be associated with that. The time coefficient corresponding to the first paired modes| centered on western Siberia| is correlated significantly with the Eurasian teleconnection pattern. Their correlation coefficients are 0.72 and 0.78 for vegetation and temperature| respectively| for the data period. Other modes are also correlated with one or more circulation indices. This implies that the large-scale circulation is essential for understanding the regional response of vegetation to global climate change. Taking all nine circulation indices and time lags into account| a large portion (71%) of the satellite-sensed variance in NDVI could be explained. The temperature-NDVI relationships did not change significantly when the NDVI was rescaled from 1 to 5 degrees| indicating that the singular value decomposition analysis is an appropriate technique for detecting the degree of coupling between vegetation and climate and that the vegetation-temperature relationship presented in this study is robust. 2739,2003,2,4,Development of gypsy moth larvae feeding on red maple saplings at elevated CO2 and temperature,Predicted increases in atmospheric CO2 and global mean temperature may alter important plant-insect associations due to the direct effects of temperature on insect development and the indirect effects of elevated temperature and CO2 enrichment on phytochemicals important for insect success. We investigated the effects of CO2 and temperature on the interaction between gypsy moth (Lymantria dispar L.) larvae and red maple (Acer rubrum L.) saplings by bagging first instar larvae within open-top chambers at four CO2/temperature treatments: (1) ambient temperature| ambient CO2| (2) ambient temperature| elevated CO2 (+300 mul l(-1) CO2)| (3) elevated temperature (+3.5degreesC)| ambient CO2| and (4) elevated temperature| elevated CO2. Larvae were reared to pupation and leaf samples taken biweekly to determine levels of total N| water| non-structural carbohydrates| and an estimate of defensive phenolic compounds in three age classes of foliage: (1) immature| (2) mid-mature and (3) mature. Elevated growth temperature marginally reduced (P <0.1) leaf N and significantly reduced (P <0.05) leaf water across CO2 treatments in mature leaves| whereas leaves grown at elevated CO2 concentration had a significant decrease in leaf N and a significant increase in the ratio of starch:N and total non-structural carbohydrates:N. Leaf N and water decreased and starch:N and total non-structural carbohydrates:N ratios increased as leaves aged. Phenolics were unaffected by CO2 or temperature treatment. There were no interactive effects of CO2 and temperature on any phytochemical measure. Gypsy moth larvae reached pupation earlier at the elevated temperature (female =8 days| P <0.07; male =7.5 days| P <0.03)| whereas mortality and pupal fresh weight of insects were unrelated to either CO2| temperature or their interaction. Our data show that CO2 or temperature-induced alterations in leaf constituents had no effect on insect performance; instead| the long-term exposure to a 3.5degreesC increase in temperature shortened insect development but had no effect on pupal weight. It appears that in some tree-herbivorous insect systems the direct effects of an increased global mean temperature may have greater consequences for altering plant-insect interactions than the indirect effects of an increased temperature or CO2 concentration on leaf constituents. 5969,2003,3,4,Development of local area wind prediction system for selecting suitable site for windmill,Nowadays| environmental concerns on the causes of global warming have led to many countries to introduce renewable energy technologies like wind power. An appropriate selection of a suitable land for wind power plants can provide significant output of energy. The final goal of this study is to develop a numerical prediction model| based on computational wind engineering| as accurate as possible to predict wind energy distribution of a local area. It aims to develop a "local area wind energy prediction system" (hereafter LAWEPS). The works involved in this project are divided into three phases. In the initial phase of the study| a multi-step wind simulation with nesting method was designed. In the second phase of the work| each sub-model was coded and evaluated. Data of observation and experiment are obtained in parallel and used for verification with computation. At the present stage of the final phase of the project| the performance of the entire simulation system| LAWEPS| is tested and examined by comparing its results with measured data. Computational fluid dynamics (CFD) models for meteorological phenomena and building scale phenomena are developed within LAWEPS for large and small areas| respectively. Results obtained from LAWEPS are promising and stimulating. This paper reports on the current status of this project and highlights on the achievements obtained within this study so far. (C) 2003 Published by Elsevier Ltd. 5983,2003,3,3,Dicyandiamide and 3|4-dimethyl pyrazole phosphate decrease N2O emissions from grassland but dicyandiamide produces deleterious effects in clover,The application of nitrogen fertilisers leads to different ecological problems such as nitrate leaching and the release of nitrogenous gases. N2O is a gas involved in global warming| therefore| agricultural soils can be regarded as a source of global warming. Soil N2O production comes from both the nitrification and denitrification processes. From an ecological viewpoint| using nitrification inhibitors with ammonium based fertilisers may be a potential management strategy to lower the fluxes of N2O| thus decreasing its undesirable effect. In this study| the nitrification inhibitors (NIs) dicyandiamide (DCD) and 3|4-dimethyl pyrazole phosphate (DMPP) have been evaluated as management tools to mitigate N2O emissions from mineral fertilisation and slurry application in grassland systems (experiments 1 and 2)| and to assess the phytotoxic effect of these inhibitors per se on clover (experiment 3)| Both nitrification inhibitors acted in maintaining soil nitrogen (N) in ammonium form| decreasing cumulative N2O emissions. DCD| but not DMPP| produced phytotoxic effects and yield reduction in white clover. A nutrient imbalance| which led to a senescence process visually observed as chlorosis and necrosis at the border of the leaves| was noted. 6321,2003,3,3,Dispersion of flue gases from power plants in Brunei Darussalam,A series of mathematical and computer models describing alternative methods for the disposal of flue gases emitted from coal and gas fired power plants is discussed. Brunei Darussalam has three gas-fired power plants using approximately 3.106 m(3)/day gas and emitting substantial flue gases into the atmosphere. After desulphurisation with sea water| carbon-dioxide| the gas primarily associated with global warming and the main constituent of flue gas| can be dissolved under pressure in seawater and injected into the sea at suitable depth. The injected solution constitutes a negatively buoyant plume in the sea| carried by currents to deeper regions. It has been noted that the solution mixes and reacts with other oceanic components and converts to carbonates and sulphates that can remain near the bottom for several hundreds of years. Until a better alternative is developed| this may be an immediate solution to the problem of dealing with flue gases. The feasibility and economics of this alternative have been discussed in the literature. For optimal design criteria for such disposal| numerous parameters (such as location| pipe diameter| type of diffuser| angles of discharge| etc.) are involved in the mathematical analysis. Many alternative sets of these parameters must be used as input parameters to arrive at final design parameters for optimal results. 6319,2003,3,3,Dissolution behavior of a CO2 droplet at the CO2 sequestration into mid-depth sea,Sequestration of liquid CO2 in intermediate depth ocean has been considered as a means to reduce atmospheric concentration of the greenhouse gas and to mitigate global warming. The dissolution behavior of CO2 in pure/sea water was investigated under the conditions of the intermediate depth ocean| i.e.| high pressure and low temperature conditions. In these conditions| CO2 clathrate hydrate film was formed at the interface between CO2 and water. The solubility of CO2 was derived by measuring the shrinking rates of the diameter of CO2 droplet. The solubility was investigated qualitatively with changing pressure| salinity and temperature. It was clarified that the solubility increased with the increase of pressure and salinity. The hydrate film| which was formed at low temperature condition| much affected the solubility. The authors applied a laser induced fluorescence (LIF) technique for the measurement of pH distribution around a CO2 droplet dissolving into pure water with or without the hydrate film. CO2 solution emitted intense fluorescence dependently on its pH. The visualized images of pH distribution| CO2 concentration around the dissolving CO2 droplet was calculated. 6063,2003,2,4,Disturbance| life history| and optimal management for biodiversity,Both frequency and intensity of disturbances in many ecosystems have been greatly enhanced by increasing human activities. As a consequence| the short-lived plant species including many exotics might have been dramatically increased in terms of both richness and abundance on our planet| while many long-lived species might have been lost. Such conclusions can be drawn from broadly observed successional cycles in both theoretical and empirical studies. This article discusses 2 major issues that have been largely overlooked in current ecosystem management policies and conservation efforts: i) life history constraints; and ii) future global warming trends. It also addresses the importance of these 2 factors in balancing disturbance frequency and intensity for optimal biodiversity maintenance and ecosystem management.
5984,2003,4,1,Do models underestimate the solar contribution to recent climate change?,Current attribution analyses that seek to determine the relative contributions of different forcing agents to observed near-surface temperature changes underestimate the importance of weak signals| such as that due to changes in solar irradiance. Here a new attribution method is applied that does not have a systematic bias against weak signals. It is found that current climate models underestimate the observed climate response to solar forcing over the twentieth century as a whole| indicating that the climate system has a greater sensitivity to solar forcing than do models. The results from this research show that increases in solar irradiance are likely to have had a greater influence on global-mean temperatures in the first half of the twentieth century than the combined effects of changes in anthropogenic forcings. Nevertheless the results confirm previous analyses showing that greenhouse gas increases explain most of the global warming observed in the second half of the twentieth century. 6087,2003,4,4,Drifts induced by multiplicative red noise with application to climate,It is well known that moment equations for a multivariate linear system with multiplicative red noise are not closed: equations for low-order moments involve higher-order moments. Further| the probability density for this system is complicated enough that analytic expressions for the moments are difficult to obtain by direct integration. We introduce a closure approximation so that the vector mean of such systems may be estimated with high accuracy. The approximation is accurate for red noises with a wide range of timescales| and approaches the correct limits for both very small and very large correlation times. We include an application relevant to climate modeling and comment on the implications for numerical-model investigations of global warming. 2789,2003,2,4,Dryness increases predation risk in efts: support for an amphibian decline hypothesis,One hypothesis for amphibian declines is that increased dryness attributed to global climate change exposes amphibians to greater biotic threat and| consequently| greater mortality. But| little is known about behavioral responses of terrestrial amphibians to dry conditions alone or in combination with biotic threats. We used field observations and laboratory experiments to test the response of efts (terrestrial juveniles) of the eastern red-spotted newt| Notophthalmus viridescens| to separate and combined desiccation and predation risks. When only at risk of desiccation| efts moved into shade| traveled down slope| decreased activity| and adopted water-conserving postures. Efts also significantly reduced the rate of water loss by huddling and were attracted to chemical cues from conspecific efts but not from conspecific adults. Thus| efts have a variety of behaviors that reduce the risk of dehydration associated with climate change. When faced only with a predation risk| represented by adult and eft newt tissue extracts (alarm chemicals)| efts reduced their activity and avoided alarm cues from both sources. When exposed to combined desiccation and predation risks| efts were less active than when exposed to either risk separately and avoided adult tissue extracts| but not eft extracts. These results suggest that under dry conditions| conspecific tissue extracts contain both attractive (huddling) and repulsive (predator-related) chemical components that induce offsetting behavioral responses. This is the first study to demonstrate moisture-dependent responses to conspecific rinses and alarm substances| underscoring the importance of considering environmental moisture and animal hydration in studies examining responses to conspecific odors and/or alarm chemicals. These results support the hypothesis that elevated dehydration risk may compromise anti-predator behavior and exacerbate amphibian population declines. 6185,2003,4,5,Dynamics of global climatic changes and possibility of their prediction using chemical data from Greenland Ice,Records from the Greenland Ice Sheet Project Two ice core are considered in terms of dynamical systems theory and nonlinear prediction. Dynamical systems theory allows us to reconstruct some properties of a phenomenon based only on past behavior without any mechanistic assumptions or deterministic models. A near-term prediction of temperature| including a mean estimate and confidence interval| is made for 800 years into the future. The prediction suggests that the present short-time global warming trend will continue for at least 200 years and be followed by a reverse in the temperature trend. 6066,2003,3,3,Economics of wastelands afforestation in India| a review,India has vast tracts of wastelands. Afforestation of these wastelands is one of the many alternative uses of such lands. Given the scarcity of capital in India| it becomes imperative to determine the economics and financial feasibility of wastelands afforestation projects. The studies reviewed in this paper deal with cost and financial feasibility analysis of wastelands afforestation projects in India. The main rationale behind this review is to examine the prospects of increasing investments in the afforestation projects. This also has a global significance| since afforestation augments carbon sequestration| which has become an exigency in view of externalities associated with global warming. The study uses review of existing literature and regression analysis as analytical tools. The review reveals that reclamation of wastelands through afforestation is not an expensive venture in India. Afforestation projects are financially viable even when no environmental benefits are taken into consideration. The results of the study suggest that polluting companies/countries should explore the possibility of investing in afforestation in India to gain carbon credits economically| once the parties to the Kyoto Protocol to the United Nations Framework Convention on Climate Change decide to approve it. The studies reviewed reveal that researchers have used different sets of criteria for financial feasibility analysis of the afforestation projects. Almost all the studies have ignored non-market benefits of afforestation projects. Such methodological differences need to be addressed in view of the increasing importance of plantations as carbon sinks. Some socioeconomic issues like investment in tree crops vis-a-vis agricultural crops| preference for mixed plantation and wastelands development as a means of resource development have also emerged from this review. 2709,2003,2,4,Ecosystem responses to global climate change: Moving beyond color mapping,Current assessments of climate-change effects on ecosystems use two key approaches: (1) empirical synthesis and modeling of species range shifts and life-cycle processes that coincide with recent evidence of climate warming| from which scenarios of ecosystem change are inferred; and (2) experiments examining plant-soil interactions under simulated climate warming. Both kinds of assessment offer indisputable evidence that climate change and its effects on ecosystems are ongoing. However| both approaches often provide conservative estimates of the effects of climate change on ecosystems| because they do not consider the interplay and feedback among higher trophic levels in ecosystems| which may have a large effect on plant species composition and on ecosystem services such as productivity| Understanding the impacts of these top-down processes on ecosystems is critical for determining large-scale ecosystem response to climate change. Using examples of links between climate forcing| trophic interactions| and changes in ecosystem state in selected terrestrial| freshwater| and marine systems| we show that the ability to understand and accurately forecast future effects of climate change requires an integrated perspective| linking climate and the biotic components of the ecosystem as a whole. 2794,2003,2,3,Effect of global climate change and human disturbances on tree diversity of the forest regenerating from clear-cuts of mixed broadleaved Korean pine forest in Northeast China,Studies on the combined effects of global climate change and human disturbances are important for biodiversity conservation and natural resources management. Here we use the modified forest dynamics model to simulate the tree diversity change of a typical mixed broadleaved Korean pine forest regenerating from clear-cuts in Northeast China in response to global climate change| double concentration Of CO2 and human disturbances during the next 50 years. We consider the following climate change scenario: the annual temperature will increase 2 degreesC| the annual precipitation will increase 10% and CO2 concentration will increase to 700 mul l(-1) linearly in 50 years. Five kinds of human disturbances under climate change are considered: logging which removes all trees with diameter at the breast height of more than 50 cm; removing all individuals of any one species; and removing all individuals of shade tolerant| shade intolerant and medium type tree species| respectively. We find that the index of proportional representation of species (alpha index) for the forest growing from clear-cuts increases significantly under climate change| but decreases under climate change plus logging. The index of changing representation of species (beta(c) index) increases significantly under climate change and climate change plus logging. When any one species is removed a diversity of the forest growing from clear-cuts changes significantly under climate change| but beta(c) index remains almost the same. When all individuals of shade tolerant species| shade intolerant species| or medium type species are removed| respectively| alpha diversity decreases| but beta(c) diversity changes in more complicated ways. The implications of these results for preserving tree diversity in this type of forest are also discussed. (C) 2003 Elsevier Science Ltd. All rights reserved. 6241,2003,3,4,Effect of N-based gases to C3F8/O-2 on global warming during silicon nitride PECVD chamber cleaning using a remote plasma source,Silicon nitride cleaning of plasma enhanced chemical vapor deposition (PECVD) chamber was carried out by NF3 and C3F3/O-2 using a remote plasma source. The effects of cleaning gases on the silicon nitride cleaning and perfluorocompounds (PFCs) emission properties were studied. To improve the cleaning properties with C3F8/O-2| N-based gases such as N-2| N2O| and NO were added to an optimized condition of C3F8/O-2 (that is| C3F8 : O-2=3:7). The silicon nitride cleaning rate was increased by about 70 % from 260 to 440 nm/min by mixing 5 to 10 % of N-based gases to C3F8(30 %) /O-2(70 %). Million metric tons of carbon equivalents (MMTCEs) were investigated and MMTCEs were decreased from 1.5 x 10(-10) to 8 x 10(-11) by the addition of 5 to 10 % N-based additive gases to C3F8(30 % /O-2(70 %). In the case of NF3| silicon nitride cleaning rate was 900 nm/min and the MMTCE was lower than 5 x 10(-11) at 600 sccm of NF3. Even though N-based gas with added C3F8/O-2 shows a higher MMTCE and a lower silicon nitride cleaning rate than those by NF3| it is believed that N-based gas with added C3F8/O-2 is replaceable to NF3 due to such advantages as relatively low price and low F-2 emission. 6126,2003,3,4,Effect of N-containing additive gases on global warming gas emission during remote plasma cleaning process of silicon nitride PECVD chamber using C4F8/O-2/Ar chemistry,In this study| remote plasma cleaning process was investigated in a silicon nitride plasma enhanced chemical vapor deposition chamber using C4F8/O-2/Ar and C4F8/O-2/Ar + additive gas. The remote plasma source used in the present experiments showed the capability of nearly complete destruction| destruction removal efficiency congruent to100%| of C4F8 gas with or without the additive N-2| N2O and NO gases. The cleaning rate of the silicon nitride layers is increased 32-40% by adding N-2| N2O and NO gases to the optimized C4F8/O-2 cleaning chemistry. This is presumably due to the effective reaction of NO radicals formed in the remote plasma with N on the silicon nitride surface| followed by the effective fluorination of Si atoms. As a result| the million metric tons of carbon equivalent values could be effectively reduced due to the decreased emission of CF4 as well as the increased cleaning rate of the silicon nitride layers| comparable to those of NF3/Ar remote plasma cleaning. For the effective reduction of global warming effects| the experimental results indicate a possibility of using the alternative gas such as C4F8 with the N-containing additive gases for the environmentally benign remote plasma cleaning process. (C) 2003 Elsevier Science B.V. All rights reserved. 6187,2003,3,3,Effect of steric hindrance on carbon dioxide absorption into new amine solutions: Thermodynamic and spectroscopic verification through solubility and NMR analysis,Acid gas absorption technology is of great importance in these days for the prevention of global warming and the resulting worldwide climate change. More efficient process design and development for the removal of acid gases has become important| together with the development of new absorbents as one of urgent areas of research in addressing global-warming problems. In the present work| aqueous solutions of 2-amino-2-hydroxymethyl-1|3-propanediol (AHPD)| a sterically hindered amine| has been examined as a potential CO2 absorbent and compared with the most commonly used absorbent| monoethanolamine (MEA) solution| through equilibrium solubility measurements and C-13 NMR spectroscopic analyses. The solubilities of CO2 in aqueous 10 mass % AHPD solutions were higher than those in aqueous 10 mass % MEA solutions above 4 kPa at 298.15 K| but below 4 kPa| the solubility behavior appeared to be the opposite. The solubility difference between these two solutions increased with the CO2 partial pressures above the crossover pressure. Equilibrated CO2-MEA-H2O and CO2-AHPD-H2O solutions at various CO2 partial pressures ranging from 0.01 to 3000 kPa were analyzed by C-13 NMR spectroscopy to provide a more microscopic understanding of the reaction mechanisms in the two solutions. In the CO2-amine-H2O solutions| amine reacted with CO2 to form mainly the protonated amine (AMH(+))| bicarbonate ion (HCO3)| and carbarnate anion (AMCO(2) where the quantitative ratio of bicarbonate ion to carbamate anion strongly influenced the CO2 loading in the amine solutions. A profusion of bicarbonate ions| but a very small amount of carbarnate anions| was identified in the CO2-AHPD-H2O solution| whereas a considerable amount of carbamate anions was formed in the CO2-MEA-H2O solution. AHPD contains more hydroxyl groups than nonhindered MEA| and hence| the chemical shifts in its C-13 NMR spectra were strongly influenced by the solution pH values. In contrast| MEA appeared to be insensitive to pH. The strong interrelations among CO2 solubility| CO2 partial pressure| bulkiness of the amine structure| and pH identified through the present experimental investigations can provide basic guidelines for finding new potential organic absorbents| including specifically designed amine chemicals. 6025,2003,2,4,Effect of temperature on the development of the aquatic stages of Anopheles gambiae sensu stricto (Diptera : Culicidae),Global warming may affect the future pattern of many arthropod-borne diseases| yet the relationship between temperature and development has been poorly described for many key vectors. Here the development of the aquatic stages of Africa's principal malaria vector| Anopheles gambiae s.s. Giles| is described at different temperatures. Development time from egg to adult was measured under laboratory conditions at constant temperatures between 10 and 40degreesC. Rate of development from one immature stage to the next increased at higher temperatures to a peak around 28degreesC and then declined. Adult development rate was greatest between 28 and 32degreesC| although adult emergence was highest between 22 and 26degreesC. No adults emerged below 18degreesC or above 34degreesC. Non-linear models were used to describe the relationship between developmental rate and temperature| which could be used for developing process-based models of malaria transmission. The utility of these findings is demonstrated by showing that a map where the climate is suitable for the development of aquatic stages of A. gambiae s.s. corresponded closely with the best map of malaria risk currently available for Africa. 6096,2003,4,3,Effects of a dynamic ocean on simulated climate sensitivity to greenhouse gases,The potential effects of a dynamic ocean on climate change are assessed by comparison of a simulation from 1880 into the future by the CSIRO (Mark 2) coupled atmosphere-ocean general circulation model with equilibrium results from a mixed-layer ocean (MLO) version of the model. At 2082| when the effective CO2 is tripled| the global warming in the coupled model is barely half the 3XCO(2) MLO result| largely because of oceanic heat uptake| as diagnosed using an effective heat capacity. The effective ocean depth continues to increase during a further 1700 years with stabilized tripled CO2| by which time the mean ocean warming reaches the upper ocean value. Some reduction of the coupled model warming is due to the effective sensitivity (for 2XCO(2))| determined from the radiative response to the forcing| being persistently 0.2 K lower than the MLO model value. A regional energy and feedback analysis shows that this is largely due to an overall equatorward oceanic heat transport anomaly| which reduces the high-latitude warming in the coupled model. The global warming at 3800 is around 95% of the anticipated equilibrium value| which is matched by the result of a simple energy balance model for the approach to equilibrium. The geographical effect of the oceanic heat transport is confirmed using a mixed-layer model with perturbed oceanic heat convergence. The eastern equatorial Pacific warming is enhanced by over 1 K| and rainfall is perturbed in an ENSO-like pattern. 6071,2003,2,3,Effects of elevated CO2 and temperature on development and consumption rates of Octotoma championi and O-scabripennis feeding on Lantana camara,We carried out a factorial experiment to explore the effect of doubled CO2 concentration and a 3 degreesC temperature increase on the development of a complete generation of the beetles Octotoma championi Baly and O. scabripennis Guerin-Meneville (Coleoptera: Chrysomelidae). These species are biological control agents of Lantana camara L. (Verbenaceae)| with a leaf-mining larval phase and free-living| leaf-chewing adults. Plants grown at elevated CO2 had enhanced above-ground biomass| thicker leaves| reduced nitrogen concentration| and increased C:N ratios. Under the high temperature treatment| plants grown at ambient CO2 suffered wilting and premature leaf loss| despite daily watering; this effect was ameliorated at elevated CO2. The wilting of plants in the ambient CO2/high temperature treatment reduced the emergence success of the beetles| particularly O. championi. Development time was accelerated by approximately 10-13 days at the higher temperature| but was not affected by CO2. Neither CO2 nor temperature affected adult beetle weight. Consumption rates of free-living beetles were not affected by either CO2 or temperature. By contrast| in the short-term trials using excised foliage| beetles given no choice between ambient and elevated CO2-grown foliage| consumed more from ambient plants. When beetles were offered a choice between foliage grown at the two CO2 levels| O. championi did not display a significant preference but O. scabripennis consumed more ambient CO2-grown foliage when feeding at the lower temperature. This study indicates that under future conditions of higher temperatures| amelioration of water stress in host plants growing in elevated CO2 may benefit some endophagous insects by reducing premature leaf loss. Under some circumstances| this benefit may outweigh the deleterious effects of lower leaf nitrogen. Our results also indicate that foliage consumption under elevated CO2 by mobile| adult insects on whole plants may not be significantly increased| as was previously indicated by short-term experiments using excised foliage. 6216,2003,2,4,Effects of elevated CO2| nitrogen and fungal endophyte-infection on tall fescue: growth| photosynthesis| chemical composition and digestibility,Rising global carbon dioxide levels may lead to profound changes in plant composition| regardless of the degree of global warming that may result from the accumulation of this greenhouse gas. We studied the interaction of a CO2 doubling and two levels of nitrogen fertilizer on the growth and chemical composition of tall fescue (Festuca arundinacea Schreber cv. KY-31) when infected and uninfected with the mutualistic fungal endophyte Neotyphodium coenophialum Morgan-Jones and Gams. Two-year-old plants were harvested to 5 cm every 4 weeks| and after 12 weeks of growth plants grown in twice ambient CO2 concentrations: photosynthesized 15% more; produced tillers at a faster rate; produced 53% more dry matter (DM) yield under low N conditions and 61% more DM under high N conditions; the % organic matter (OM) was little changed except under elevated CO2 and high N when %OM increased by 3%; lignin decreased by 14%; crude protein (CP) concentrations (as %DM) declined by 21%; the soluble CP fraction (as %CP) increased by 13%; the acid detergent insoluble CP fraction (as %CP) increased by 12%| and in vitro neutral detergent fiber digestibility declined by 5% under high N conditions but not under low N. Plants infected with the endophytic fungus: photosynthesized 16% faster in high N compared with under low N; flowered earlier than uninfected plants; had 28% less lignin in high N compared with under low N; and had much smaller reductions in CP concentration (as %DM) and smaller increases in the soluble CP fraction (as %CP) and the acid detergent insoluble CP fraction (as %CP) under elevated CO2. Such large and varied changes in plant quality are likely to have large and significant effects on the herbivore populations that feed from these plants. 6204,2003,2,4,Effects of elevated seawater temperature and nitrate enrichment on the branching coral Porites cylindrica in the absence of particulate food,Compounded disturbances are becoming increasingly common on coral reefs. Impacts of global warming| which is generally perceived as the most serious threat to coral reefs today| often coincide with various common anthropogenic disturbances| such as pollution and overharvesting. To better evaluate the impact of global warming| interactions between elevated temperature and background disturbance should be investigated. In this study| the physiological response of the reef-building coral Porites cylindrica was investigated| when exposed to enrichment of dissolved inorganic nitrate (+ 15 muM for 14 days) and elevated seawater temperature ( + 2 C for 48 h)| in the absence of particulate food. It was shown that P. cvlindrica was able to tolerate the temperature exposure without losing symbiotic microalgae or chlorophyll pigments| although the photosynthetic capacity was affected. Nitrate enrichment significantly reduced primary production rate| although zooxanthella population density and chlorophyll concentrations were not affected. The combination of elevated temperature and nitrate enrichment produced an even more pronounced reduction of the production rate. Since coral respiration rate remained unaffected by the treatments| this implies that the corals were unable to acclimate to impaired photosynthesis. However| there was no indication of subsequently reduced tissue growth or increased host catabolism based on tissue biomass measurements. On the other hand| all corals| including controls| lost tissue biomass during the exposure| suggesting a dependence on particulate food. Our results imply that corals on nutrient-exposed reefs may be more stressed during periods of elevated temperature| compared to corals in more pristine areas. 2805,2003,2,4,Effects of hard frost and freeze-thaw cycles on decomposer communities and N mineralisation in boreal forest soil,Decomposition and mineralisation rates generally increase with increasing moisture and temperature. The expected global climate change may enhance precipitation and raise the temperatures at boreal latitudes| but absence of snow together with occasional low temperatures may cause disturbances in soil processes and faunal communities. To test the effects of disturbances such as hard frosts and freeze-thaw cycles on decomposer populations and N mineralisation| we performed two experiments. In the field experiment| carried out in a pine forest| we induced low soil temperatures by preventing snow covering the ground. In the laboratory test we established three "winter" temperature regimes: constant -2degreesC| freeze-thaw cycles of -2degrees to +2degreesC| and the latter with two hard frost periods (-16degreesC). The microcosm experiment included two decomposer communities; the "simple" community included microbes| protozoa and nematodes| and the "complex" community microbes| protozoa| nematodes| enchytraeids and microarthropods. In the field experiment| the populations of enchytraeids and several microarthropod taxa| as well|as microarthropod species richness| decreased in snowfree plots. In the microcosms| virtually all enchytraeids died and microarthropod populations and taxa decreased in the hard frost treatment| but increased in the freeze-thaw treatment. In the laboratory systems with simple decomposer community structure the amount of mineral nitrogen decreased in the freeze-thaw treatment. The experiments revealed that exceptionally low soil temperatures exert a stronger influence on soil fauna than constant benign temperatures or freeze-thaw cycles| but the rapid recovery of populations may counteract the detrimental effect of occasional frost periods. (C) 2002 Elsevier Science B.V. All rights reserved. 6170,2003,3,4,Effects of N-fertilisation on CH4 oxidation and production| and consequences for CH4 emissions from microcosms and rice fields,The world's growing human population causes an increasing demand for food| of which rice is one of the most important sources. In rice production nitrogen is often a limiting factor. As a consequence increasing amounts of fertiliser will have to be applied to maximise yields. There is an ongoing discussion on the possible effects of fertilisation on CH4 emissions. We therefore investigated the effects of N-fertiliser (urea) on CH4 emission| production and oxidation in rice microcosms and field experiments. In the microcosms| a substantial but short-lived reduction of CH4 emission was observed after N-addition to 43-d-old rice plants. Methane oxidation increased by 45%| demonstrated with inhibitor measurements and model calculations based on stable carbon isotope data (delta(13) CH4 ). A second fertilisation applied to 92-d-old plants had no effect on CH4 emission rates. The positive effect of additional N on methanotrophic bacteria was also found in vitro for potential CH4 oxidation rates in soil and root samples from the microcosm and field experiments| indicated by elevated initial oxidation rates and reduced lag-phases. Fertilisation did not affect methane production in the microcosms. In the field| the effects were diverse: methane production was inhibited in the topsoil| but stimulated instead in the bulk soil. Stimulation occurred probably in the anaerobic food chain at the level of hydrolytic or fermenting bacteria| because acetate| a methanogenic precursor| increased simultaneously. Combining field| microcosm and laboratory experiments we conclude that any agricultural treatment improving the N-supply to the rice plants will also be favourable for the CH4 oxidising bacteria. However| N-fertilisation had only a transient influence and was counter-balanced in the field by an elevated CH4 production. A negative effect of the fertilisation was a transient increase of N-2 O emissions from the microcosms. However| integrating over the season the global warming potential (GWP) of N-2 O emitted after fertilisation was still negligible compared to the GWP of emitted CH4 . 6077,2003,2,4,Effects of spatial and temporal variability in soil moisture on widths and delta C-13 values of eastern Siberian tree rings,We studied the relationships between earlywood/latewood width| stable carbon isotope ratio (delta(13)C) of cellulose| and soil moisture at a dry and a wet site in Yakutsk| eastern Siberia| which differed considerably in soil water conditions. Recharge of soil water by snowmelt in spring and subsequent drought in summer provided a marked seasonal contrast in soil water conditions between the earlywood and latewood formation period. Ring index was calculated by dividing each earlywood/latewood width by the 5-year averaged width for each individual. In order to determine whether drought influenced the ring index-delta(13)C relation| the ring index time series were compared with delta(13)C time series. We collected wood samples from eight Larix gmelinii (Rupr.) Rupr. and four Pinus sylvestris L. trees from the two sites and measured the earlywood and latewood widths and delta(13)C of earlywood and latewood formed during the years 1996-2000. At the dry site| seasonal soil water content variation corresponded to seasonal delta(13)C variation of tree rings. We found negative ring index-delta(13)C correlations in latewood for both species at the dry site mainly dominated by Pinus but not in latewood of Larix at the wet site dominated by Larix. Decrease and/or early cessation of latewood growth and increase in delta(13)C under drought conditions possibly explain this negative correlation. This suggests the growth limitation of trees in this region by drought and the prospects of reconstructing past drought with latewood delta(13)C of the dry site. 6275,2003,3,3,Effects of SRT and DO on N2O reductase activity in an anoxic-oxic activated sludge system,Nitrous oxide (N2O) is emitted from wastewater treatment processes| and is known to be a green house gas contributing to global warming. It is thus important to develop technology that can suppress N2O emission. The effects of sludge retention time (SRT) and dissolved oxygen (DO) on N2O emission in an anoxic-oxic activated sludge system were estimated. Moreover| the microbial community structure in the sludge| which plays an important role in N2O Suppression| was clarified based on nitrous oxide reductase (nosZ) gene analysis by molecular biological techniques. The results showed that under low SRT conditions| nitrification efficiency was reduced and the N2O emission rate in the oxic reactors was increased. It was also observed that N2O emission was enhanced under low DO conditions| where the available oxygen is insufficient for nitrification. Moreover| molecular analysis revealed that the clones identified in this study were closely related to Ralstonia eutropha and Paracoccus denitrificans. The fact that the identified sequences are not closely related to known culturable denitrifier nosZ sequences indicates a substantial in situ diversity of denitrifiers contributing to N2O suppression| which are not reflected in the cultivatable fraction of the population. The further application of these new molecular techniques should serve to enhance our knowledge of the microbial community of denitrifying bacteria contributing to N2O suppression in wastewater treatment systems.
6031,2003,2,4,Effects of UVB preconditioning on heat tolerance of cucumber (Cucumis sativus L.),To study the preconditioning effects of exposure to UVB on heat tolerance (44-48 degreesC)| 10-day-old cucumber (Cucumis sativus L.) seedlings were irradiated for 6 days with a daily dose of either 3.4| 5.5 or 10.6 kJ m(-2) of biologically effective UVB (UVBBE). Cellulose diacetate-filtered UVB lamps were used to supply UVB. These approximated low| ambient (medium) and twice-ambient (high) UVB doses| respectively| at 42degreesN latitude on a clear day during the summer solstice. A parallel group of control plants| held under polyester (PE)-filtered UVB lamps| received no UVB. UVB treatment increased the level of methanol-extractable UV-absorbing phenols in cotyledons and primary leaves. In a further HPLC analysis of acid-hydrolyzed leaf extract| eight peaks were separated. The two major peaks were co-chromatographed with authentic flavonoids| quercetin and kaempferol. The quercetin-like compound was preferentially enhanced in UVB-exposed plants. When the low and medium UVB-irradiated plants were later heat-stressed (46 degreesC| 1 h)| survival improved by 112 and 82% and height growth increased by 35 and 40%| respectively| compared with controls that received no UVB. In contrast to low and ambient levels of UVB| which reduced membrane leakage| twice-ambient levels increased lipid peroxidation and electrolyte leakage. Although exposure to above-ambient levels of UVB was injurious| low and ambient doses of UVB promoted survival and growth of cucumber seedlings. Such a synergism between UVB and heat tolerance could be used to precondition seedlings grown in UVB-deficient greenhouses and may benefit plants under the predicted global warming scenario. (C) 2003 Elsevier Science B.V. All rights reserved. 6043,2003,2,4,El Nino drives timing of breeding but not population growth in the song sparrow (Melospiza melodia),Increasing evidence suggests that climate change affects the timing of breeding in birds| but there is less evidence to show how such changes affect the population dynamics of birds overall. Over the past 43 years| song sparrows (Melospiza melodia) on Mandarte Island| British Columbia| Canada have not shown an advance in breeding date in response to global warming. However| this population did show considerable annual variation in timing of breeding correlated with the El Nino Southern Oscillation. Birds bred earlier in warmer El Nino years and later in colder La Nina years. Early breeding strongly increased reproductive output. However| annual variation in timing of breeding had little effect on population growth| perhaps because the population is strongly regulated by the rate of recruitment by juveniles. The juvenile recruitment rate declined with increasing population density but showed little response to climate. These findings suggest that populations will vary in response to climate change depending on how climate affects the demographic parameters that contribute most to population growth. 6057,2003,4,3,Electron and photon induced processes in SF(5)CF(3),The photo-absorption cross section of trilluoromethyl sulphur pentafluoride| SF(5)CF(3) has been measured using synchrotron radiation in the range of 4-11 eV (310 nm > X > 110 nm) and comparison made with electron energy loss spectroscopy (EELS). The. measured VUV cross sections are used to derive the photolysis rate of SF5CF3 in the terrestrial atmosphere. It is estimated that the lifetime for this molecule is the order of a 1000 years and the calculated global warming potential (GWP) is found to be between 17000 and 18100| making it one of the most potent global warming gases in the terrestrial atmosphere. (C) 2003 Elsevier Science Ltd. All rights reserved. 2828,2003,2,4,Elevated sea-surface temperature| reduced provisioning and reproductive failure of wedge-tailed shearwaters (Puffinus pacificus) in the southern Great Barrier Reef| Australia,During the 2002 austral summer abnormally high sea-surface temperatures (SST) occurred in the southern Great Barrier Reef (GBR)| Australia. This phenomenon was accompanied by reduced provisioning| decreased growth rates and reproductive failure of wedge-tailed shearwaters in the region. In 2002| adults were unable to compensate for changes in either the availability and/or accessibility of forage-fish by increasing food loads or foraging rates. This is one of few studies to explicitly correlate decreases in chick provisioning with above-average annual variation in SST and is the first to do so for a tropical seabird species in the western Pacific. It adds to an increasing number of data sets identifying the potential negative impacts of increasing SST at upper-trophic levels. As SST continue to rise with global climate change| our results predict substantial detrimental effects on seabird populations of the GBR. This finding has important implications for both seabird and coral reef ecosystem management in the region. Our results also suggest that wedge-tailed shearwaters are sensitive indicators to changes in forage-fish availability/accessibility associated with SST variation that can be used to develop models of| and monitor for| these potential impacts. 6323,2003,3,3,empirical investigation of household vehicle type choice decisions,Automobile ownership models are an integral part of comprehensive transportation modeling systems. Recent work and ongoing advances in the area of activity-based travel demand modeling have recognized the need for increased experimentation with automobile choice models. On the other hand| while automobiles are very important in people's everyday lives| they also have a serious impact on the environment. This impact occurs at the micro level (pollution) as well as the macro level (emission of greenhouse gases and global warming). Such impacts have led to increased interest in reducing motor vehicle emissions. A household automobile type choice model was developed at a disaggregate level. The model can provide a direct forecast of consumer demand for personal-use vehicles given the available choices. A well-developed form of discrete choice modeling techniques| the nested logit model| was used to investigate the process of household automobile type choice decisions given that a transaction has occurred. 6277,2003,3,2,Energy and environmental issues relating to greenhouse gas emissions in Turkey,States have played a leading role in protecting the environment by reducing emissions of greenhouse gases (GHGs). State emissions are significant on a global scale. CO2 and CO are the main GHGs associated with global warming. At the present time| coal is responsible for 30-40% of the world CO2 emissions from fossil fuels. SO2 and NOx contribute to acid rain. Carbon assessments can play an important role in a strategy to control carbon dioxide emissions while raising revenue. In 1992| Turkish Ministry of Environment issued a regulation providing for emissions testing for cars| trucks and vans. (C) 2002 Elsevier Science Ltd. All rights reserved. 6093,2003,3,3,Energy systems and the climate dilemma - Reflecting the impact on CO2 emissions by reconstructing regional energy systems,Global warming is one of the most important environmental issues today. One step for the European Union to fulfil the Kyoto protocol| stating a worldwide decrease of emissions of greenhouse gases| is to treat the environment as a scarce resource by attributing costs for environmental impact. This accompanied with considering the European electricity market as one common market| where coal condensing power is the marginal production| lead to the possibility to reduce CO2-emissions in Europe by reconstructing energy systems at a local scale in Sweden. A regional energy system model is used to study possibilities to replace electricity and fossil fuel used for heating with biomass and how a reconstruction can affect the emissions of CO2. An economic approach is used where cost-effective technical measures are analysed using present conditions and by including monetary values of externalities. The analysis shows that| by acting economically rational| a large amount of electricity and fossil fuel should| in three Out Of four cases| be replaced leading to a substantial reduction of CO2 emissions. (C) 2002 Elsevier Science Ltd. All rights reserved. 2774,2003,2,4,Enhanced growth of sagebrush (Artemisia tridentata) in response to manipulated ecosystem warming,Global models project impending climate changes that could significantly alter plant species composition in ecosystems. Climate manipulation experiments provide an opportunity to investigate such effects. Here we describe and apply a method for extracting the age-detrended growth rate of sagebrush (Artemisia tridentata Nutt.) and show that experimental ecosystem warming enhances the growth rate of this shrub. Snowmelt date| not soil temperature or moisture| is demonstrated to be the dominant climate variable controlling the observed effect. Our findings suggest that global climate change will result in increased growth and range expansion of sagebrush near northern or high-elevation range boundaries in the Western United States. 6173,2003,2,4,ENSO| rainfall and temperature influences on extreme population declines among African savanna ungulates,Climatic variation associated with the North Atlantic Oscillation (NAO) and El Nino-Southern Oscillation (ENSO) has a widespread influence on the population dynamics of many organisms worldwide. While previous analyses have related the dynamics of northern ungulates to the NAO| there has been no comparable assessment for the species rich assemblages of tropical and subtropical Africa. Census records for 11 ungulate species in South Africa's Kruger National Park over 1977-96 reveal severe population declines by seven species| which were inadequately explained by indices of ENSO or its effects on annual rainfall totals. An additional influence was an extreme reduction in dry season rainfall| concurrent with and perhaps related to a regional temperature rise| possibly a signal of global warming. Boundary fencing now restricts range shifts by such large mammals in response to climatic variation. Our models project near extirpation of three ungulate species from the park's fauna should these climatic conditions recur. 6217,2003,3,4,Environmental benefits of livestock manure management practices and technology by life cycle assessment,An environmental Life Cycle Assessment (LCA) procedure is constructed to compare the total emissions from different techniques for managing livestock wastes. Life Cycle Assessment is a method of holistically and systematically accounting for the environmental benefits and burdens of the production of goods and services including consequential burdens generated elsewhere. As waste emissions are very variable| the methodology is extended to include the uncertainty in the estimates in order to indicate the significance of differences between techniques. The object is to inform policy of whether options are better for the environment by quantifying potential emissions abatement| by highlighting priority environmental impacts and by revealing compromises for further investigation. This paper reports comparative LCAs for several pig waste management options. For example| various slurry application techniques| including: splash plates| band spreaders and injection. If the splash-plate system is taken as a reference| the injector system causes only 64% of the environmental acidification and 71% of the eutrophication of surface waters. The benefits must be offset against the increase in nitrate leaching of 50%. In contrast| the band spreader system offers 28% of the benefits of injection. The environmental impacts have also been expressed as a proportion of the UK national emissions. This gives each impact a weighted-value that enables direct comparisons of disparate impacts. Although band spreader systems showed an aggregated| or total| environmental impact reduction of almost 10%| the reduction is not significant when uncertainty is taken into account. Using an anaerobic digester shows few overall benefits due to the fugitive losses of methane. However| if these can be eliminated the global warming potential from waste management is reduced close to zero. (C) 2003 Silsoe Research Institute. All rights reserved. Published by Elsevier Science Ltd. 2751,2003,3,4,Environmental degradation and remediation: Is economics part of the problem?,It is argued that standard environmental economic and 'ecological economics'| have the same fundamentals of valuation in terms of money| based on a demand curve derived from utility maximization. But this approach leads to three different measures of value. An invariant measure of value exists only if the consumer has 'homothetic preferences'. In order to obtain a numerical estimate of value| specific functional forms are necessary| but typically these estimates do not converge. This is due to the fact that the underlying economic model is not structurally stable. According to neoclassical economics| any environmental remediation can be justified only in terms of increases in consumer satisfaction| balancing marginal gains against marginal costs. It is not surprising that the optimal policy obtained from this approach suggests only small reductions in greenhouse gases. We show that a unidimensional metric of consumer's utility measured in dollar terms can only trivialize the problem of global climate change. 6218,2003,3,3,Environmental impact assessment of conventional and organic milk production,Organic agriculture addresses the public demand to diminish environmental pollution of agricultural production. Until now| however| only few studies tried to determine the integrated environmental impact of conventional versus organic production using life cycle assessment (LCA). The aim of this article was to review prospects and constraints of LCA as a tool to assess the integrated environmental impact of conventional and organic animal production. This aim was illustrated using results from LCAs in the literature and from a pilot study comparing conventional and organic milk production. This review shows that LCAs of different case studies currently cannot be compared directly. Such a comparison requires further international standardisation of the LCA method. A within-case-study comparison of LCAs of conventional and organic production| however| appeared suitable to gain knowledge and to track down main differences in potential environmental impact. Acidification potential of milk production| for example| is for 78-97% due to volatilisation of ammonia| which is not reduced necessarily by changing from conventional to organic milk production. Eutrophication potential per tonne of milk or per ha of farmland was lower for organic than for conventional milk production due to lower fertiliser application rates. Global warming potential of milk production is for 48-65% due to emission of methane. Organic milk production inherently increases methane emission and| therefore| can reduce global warming potential only by reducing emission of carbon dioxide and nitrous oxide considerably. Organic milk production reduces pesticide use| whereas it increases land use per tonne of milk. Conclusions regarding potential environmental impact of organic versus conventional milk production| however| are based largely on comparison of experimental farms. To show differences in potential environmental impact among various production systems| however| LCAs should be performed at a large number of practical farms for each production system of interest. Application of LCA on practical farms| however| requires in-depth research to understand underlying processes| and to predict| or measure| variation in emissions realised in practice. (C) 2002 Published by Elsevier Science B.V. 6229,2003,3,3,Environmental impact oil fossil fuel fired co-generation plants using a numerically standardized LCA scheme,This paper describes the LCA environmental impacts resulting from fuel fired co-generation systems using our NETS (Numerical Eco-load Total Standard-[1]) scheme having GUI (Graphic User Interface). Following a brief introduction of the NETS evaluation method| firstly the total eco-load from commercial electricity power plants in Japan is numerically calculated in the NETS unit. We take here almost all factors into account including fuel mining| transportation and processing| plant manufacturing| assembling and its building construction| fuel consumption and maintenance during twenty durable years| plant dismantling and waste processing| thermal efficiency and delivery loss| etc. This evaluation greatly helps in the eco-load estimation of co-generation plants when electricity purchase is needed during the plant operation with a minimum eco-load. Next| co-generation systems are paid attention to their ecological effiectiveness. Here| we select different fuel fired co-generation plants of natural gas| heavy oil| and coal. Environmental impacts resulting from the respective plants include fossil fuel depletion and natural resources depletion| global warming due to green house gases| ozone layer depletion due to CFC type gas emission| various water and air pollution| rain acidification due to NOx and SOx| waste processing| recycling etc. Each item can be successfully calculated from the inventory database accumulated by authors. Hourly energy demands of electricity and heat (steam| hot water and cold water) are set to a typical model for eight office buildings and two hotels. The NETS method is applied to the co-generation model| resulting in the best cost-operating scheme of co-generation plants with a minimum environmental impact. 6302,2003,3,3,Environmentally benign etching process of amorphous silicon and tungsten using species evaporated from polytetrafluoroethylene and fluorinated ethylene propylene,Environmentally benign etching process of amorphous silicon (a-Si) and tungsten (W) by using a plasma process with an evaporation of solid materials system has been developed for replacing a conventional plasma process using green house gases| such as SF6 gas and perfluorocompound gases causing global warming. The evaporation system was designed to generate fluorocarbon species from solid materials by a CO| laser irradiation. An electron cyclotron resonance (ECR) plasma using O-2 accompanied with injection of species evaporated from solid materials has been applied to a-Si and W etching for cleaning process in chemical vapor deposition chamber. Fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE) are selected as the solid material and the etching characteristics between FEP and PTFE have been compared. Furthermore| the etching of a-Si and W films has been performed in the divergent magnetic field ECR downstream plasma [electron density (n(e)); similar to 10(10) cm(-3)| electron temperature (T-e); 1.5-2.8 eV] and a planar ECR plasma [n(e); similar to10(10) cm(-3)| T-e; 3.4-4.4 eV] using O-2 gas with FEP evaporation. As a result| high etching rates of a-Si and W films of above 100 nm/min were successfully obtained at a substrate temperature of 400 degreesC in the planar ECR plasma of higher electron temperature. CFx (x = 1-3) radical densities and F atom density in plasmas were measured by an infrared diode laser absorption spectroscopy and an actinometric optical emission spectroscopy. respectively. On the basis of these measurements of species. the etching mechanisms of a-Si and W films are discussed. (C) 2003 American Vacuum Society. 5995,2003,3,4,Estimating the environmental impact of catastrophic chemical releases to the atmosphere - An index method for ranking alternative chemical process routes,This paper presents an index called the atmospheric hazard index (AHI)| which can be used to assess the potential impact of airborne releases from a chemical production plant. A catastrophic failure of the plant is assumed and the impacts on the atmospheric environment are estimated. The method is designed for assessing possible alternative process routes [the raw material(s) and the sequence of reaction steps that converts them to the desired product(s)] to make a chemical| in order to determine the route that has the least adverse atmospheric environmental impact. Thus the routes that are inherently environmentally hazardous can be identified and avoided when the selection is made in the early stages of production plant design. The atmospheric impact categories considered are toxicity| photochemical smog| acid deposition| global warming and stratospheric ozone depletion. The magnitude of these impacts are expressed on a scale of 0 (minimum) to 10 (maximum). Each of these impact categories is assigned an importance factor value (I) depending upon: the spatial scale affected by| the degree of 'directness' of and the reversibility of the impact. These factors are used to calculate a weighted category hazard (WCH) value for each chemical. The WCH of all the impact categories and chemicals are combined to estimate the AHI. The AHI has been tested on six potential and established routes to methyl methacrylate (MMA). The route based on propylene has the lowest AHI value. In all the routes the storage inventory has the potential to cause the most environmental damage compared with the reaction and separation inventories. 6284,2003,3,4,Estimation of methane emission from rice cultivation in Korea,This study focused on estimating a methane (CH4) inventory and developing mitigation options in South Korea| and was performed jointly in an integrated national research program on CH4 from rice fields conducted by three National Agricultural Research Institutes| under the Rural Development Administration during 1993-1997. Methane emissions were measured by a closed chamber method| in rice plots at three locations (Suwon| Iksan| and Milyang) with the single rice cropping system. All experimental data from 5 years of study were summarized and used for calculating nation-wide CH4 emissions. Temperature| soil type| cultural practices| water management| organic matter management| and cultivar selection significantly affected the fluctuations of CH4 emissions. The two most promising mitigation options for reducing emissions were altered water management| in particular mid-season aeration by short-term drainage| and improved organic matter management| by promotion of aerobic degradation through composing or soil incorporation. Annual total CH4 emission in Korea changed from 410 Gg in 1990 to 339 Gg in 2000| due mainly to a decrease in the cultivated area of paddy rice. If we convert annual CH4 emission to Global Warming Potential as CO2 equivalent| it amounts to 7.1M CO2 t yr(-1) of greenhouse gas emitted to the atmosphere in 2000 from-the rice fields in Korea| which is just 5.3% of the annual CO2 emission from the industry and energy sector. More importantly| the balance between CO2 uptake by photosynthesis and CO2 emission is positive (a net|sink)| so that rice culture actually has net benefits for the global atmospheric carbon issue. Further reductions in emission amounts| by following recommendations in this article| could make these benefits even greater. 6208,2003,4,4,Estimation of soil degradation rate constants from vertical distribution of soil carbon content,A simple model interpreting vertical distribution of soil carbon was constructed and annual degradation rate constants of soil carbon for various forest soils were estimated. The model is based on the material balance at the soil surface| and assumes that the relationship between soil depth and soil carbon is linear. The estimated soil degradation rates were of the similar order of magnitude| and we concluded that this model might be used for rough estimation of soil carbon degradation rates of forest soils where vertical distributions of soil carbon are available. 6157,2003,2,4,European river floods in a changing world,Whereas the verdict is undecided about the effects of global warming on Europe's flood risks| it is clear that Europeans are becoming more exposed and vulnerable to floods. Losses are increasing dramatically| mainly because of population and capital moving into harm's way and also because of human-driven transformations of hydrological systems| including river basins and floodplains. 2792,2003,4,4,Evaluating predictive models of species' distributions: criteria for selecting optimal models,The Genetic Algorithm for Rule-Set Prediction (GARP) is one of several current approaches to modeling species' distributions using occurrence records and environmental data. Because of stochastic elements in the algorithm and underdetermination of the system (multiple solutions with the same value for the optimization criterion)| no unique solution is produced. Furthermore| current implementations of GARP utilize only presence data-rather than both presence and absence| the more general case. Hence| variability among GARP models| which is typical of genetic algorithms| and complications in interpreting results based on asymmetrical (presence-only) input data make model selection critical. Generally| some locality records are randomly selected to build a distributional model| with others set aside to evaluate it. Here| we use intrinsic and extrinsic measures of model performance to determine whether optimal models can be identified based on objective intrinsic criteria| without resorting to an independent test data set. We modeled potential distributions of two rodents (Heteromys anomalus and Microryzomys minutus) and one passerine bird (Carpodacus mexicanus)| creating 20 models for each species. For each model| we calculated intrinsic and extrinsic measures of omission and commission error| as well as composite indices of overall error. Although intrinsic and extrinsic composite measures of overall model performance were sometimes loosely related to each other| none was consistently associated with expert-judged model quality. In contrast| intrinsic and extrinsic measures were highly correlated for both omission and commission in the two widespread species (H. anomalus and C mexicanus). Furthermore| a clear inverse relationship existed between omission and commission there| and the best models were consistently found at low levels of omission and moderate-to-high commission values. In contrast| all models for M. minutus showed low values of both omission and commission. Because models are based only on presence data (and not all areas are adequately sampled)| the corm-nission index reflects not only true commission error but also a component that results from undersampled areas that the species actually inhabits. We here propose an operational procedure for determining an optimal region of the omission/commission relationship and thus selecting high-quality GARP models. Our implementation of this technique for H. anomalus gave a much more reasonable estimation of the species' potential distribution than did the original suite of models. These findings are relevant to evaluation of other distributional-modeling techniques based on presence-only data and should also be considered with other machine-learning applications modified for use with asymmetrical input data. (C) 2002 Elsevier Science B.V. All rights reserved. 6145,2003,3,4,Evaluating uncertainty in environmental life-cycle assessment. A case study comparing two insulation options for a Dutch one-family dwelling,The evaluation of uncertainty is relatively new in environmental life-cycle assessment (LCA). It provides useful information to assess the reliability of LCA-based decisions and to guide future research toward reducing uncertainty. Most uncertainty studies in LCA quantify only one type of uncertainty| i.e.| uncertainty due to input data (parameter uncertainty). However| LCA outcomes can also be uncertain due to normative choices (scenario uncertainty) and the mathematical models involved (model uncertainty). The present paper outlines a new methodology that quantifies parameter| scenario| and model uncertainty simultaneously in environmental life-cycle assessment. The procedure is illustrated in a case study that compares two insulation options for a Dutch one-family dwelling. Parameter uncertainty was quantified by means of Monte Carlo simulation. Scenario and model uncertainty were quantified by resampling different decision scenarios and model formulations| respectively. Although scenario and model uncertainty were not quantified comprehensively| the results indicate that both types of uncertainty influence the case study outcomes. This stresses the importance of quantifying parameter| scenario| and model uncertainty simultaneously. The two insulation options studied were found to have significantly different impact scores for global warming| stratospheric ozone depletion| and eutrophication. The thickest insulation option has the lowest impact on global warming and eutrophication| and the highest impact on stratospheric ozone depletion. 6010,2003,4,4,Evaluation of FNO and F3NO as substitute gases for semiconductor CVD chamber cleaning,Two types of FNO compounds (FNO and F3NO) were evaluated as candidates for new chemical vapor deposition (CVD) chamber cleaning gases. NF3 and C2F6 were measured as the reference. Like NF3| as these gases have no carbon in their molecules| no perfluoro carbon (PFC) is thought to be emitted. FNO is a compound highly susceptible to hydrolysis. F3NO is expected to decompose more easily than NF3 in the atmosphere because its N-F bond has been weakened by introducing an N=O bond into the molecule. Hence| the contribution to global warming of these compounds is expected to be small. Performance of these gases was evaluated by measuring their etch rates and their exhaust gases. The results showed that the etch rate of F3NO is virtually the same as that of NF3| whereas the etch rate of FNO is about 1/2 that of NF3. However| from the results of exhaust gas analysis| it was found that an unexpected side reaction had occurred in the chamber| and therefore| it was confirmed that it is important to take this property into account in designing applications. (C) 2003 The Electrochemical Society. 6168,2003,4,4,Evidence for recent changes in a surface-air warming singularity in late winter over central North America,[1] Evidence for an earlier onset of spring in recent years is supported by daily temperature data from central North America. From 1976-1999| mean temperatures during February 15th through 24th were appreciably higher (5degreesC or more over large areas) than during 1952-1975. This is associated with a strengthened Aleutian Low for those calendar days during 1976-1999| with negative pressure anomalies extending well into North America. This apparently reflects a decrease in strong| cold| high-pressure systems moving from western Canada into the north central United States during late February. These changes appear to be related to conditions in and over the North Pacific Ocean| possibly in conjunction with global warming| although the latter signal is not clearly obvious. Comparison of time series of daily minimum temperatures for the earlier period (1952 1975) and the recent period (1976-1999) indicates other times of the year when an appreciable warming has occurred; such warming is largely confined to the first half of the calendar year. 6095,2003,2,4,Feedbacks affecting the response of the thermohaline circulation to increasing CO2: a study with a model of intermediate complexity,A three-dimensional ocean model with an idealized geometry and coarse resolution coupled to a two-dimensional (zonally averaged) statistical-dynamical atmospheric model is used to simulate the response of the thermohaline circulation to increasing CO2 concentration in the atmosphere. The relative roles of different factors in the slowing down and recovery of the thermohaline circulation were studied by performing simulations with ocean only and partially coupled models. The computational efficiency of the model allows an extensive and thorough study of the causes of changes in the strength of the thermohaline circulation| through a large number of extended runs. The evolution of the atmosphere-to-ocean surface heat fluxes is shown to be the dominant factor in causing the weakening of the circulation in response to an increasing external forcing as well as in controlling the subsequent recovery. The feedback between heat flux and the sea surface temperature is necessary for the ocean circulation to recover. The rate of the recovery| however| is not sensitive to the magnitude of the feedback| and changes in the atmosphere| while contributing to the recovery| play a secondary role. In the case of very strong feedback| substantial changes in the SST structure are shown not to be a necessary condition for the recovery of the circulation. Subsurface changes in the density structure accompany recovery despite nearly fixed SST in one of the uncoupled experiments. Changes in the zonal distribution of heat fluxes serve as a positive feedback for both decrease and recovery of the meridional overturning| and are as important as changes in the zonal-mean values of heat fluxes. The secondary role of the moisture fluxes is explained by a smaller magnitude of their contribution to the surface buoyancy flux. Imposing amplified changes in the moisture fluxes leads to a significant slow down of the circulation| accompanied| however| by changes in the heat flux. The changed heat flux| in its turn| makes a significant contribution to the future slow down. This feedback complicates the evaluation of the relative roles of the different fluxes. 5967,2003,4,4,Field measurements of atmosphere-biosphere interactions in a Danish beech forest,A field station was established in a beech forest near Soro| Denmark in the spring of 1996 to provide a platform for Studies of atmosphere-biosphere interactions. The station is equipped with a 57-m mast and a 24-m scaffolding tower. The mast makes it possible to measure profiles of gaseous atmospheric compounds and meteorological variables and to undertake measurements of fluxes by the eddy covariance method. The tower gives access to the tree canopy where branch and leaf level exchange of water vapour and CO2 is measured. Soil-atmosphere exchange of gaseous compounds is investigated with gas flux chambers on the soil surface. Water-mediated transport of C and N is measured in throughfall| stemflow and soil water. The paper provides information on the site| vegetation| climate and soil and gives a description of the instrumentation and other technical installations at the site. The paper also presents and discusses example results from the measurements such as meteorological variables (temperature| wind speed| wind direction| radiation| rainfall and relative humidity)| gaseous concentrations (O-3) and fluxes (CO2| CH4 and N2O)| water mediated transport (NO3- and NH4+ in rainfall| throughfall| stemflow and soil water) and measurements on the trees (leaf area index| specific leaf area| litter fall| CO2 exchange at branch and leaf level| maximum photosynthetic capacity). The forest acted in all years as a carbon sink with an average uptake of 190 g C m(-2) yr(-1). Contributions| from CH4 and N2O in terms of global warming potential (GWP) were less than 10% of the CO2. CH4 was deposited and NO emitted| almost neutralising each other in terms of GWP Leaves at the top of the canopy had the highest photosynthetic capacity (mid summer maximum of 50 mumol m(-2) s(-1)) and leaves at the bottom the lowest (20 mumol m(-2) s(-1))| indicating a clear acclimation to light. Sun leaves generally had significantly lower specific leaf area (118 cm(2) g(-1)) and water content (42%) than shade leaves (specific leaf area: 282 cm(2) g(-1); water content: 53%). On an annual basis about 24% of the precipitation was lost as evaporation| 66% reached the forest floor as throughfall and 10% as stemflow. Due to leaching of NO3- from the trees| the forest floor received 30% more nitrogen than in precipitation| resulting in a total input of 2.9 g N m(-2) yr(-1)). The soil water was almost completely depleted in NO3- with NH4+ constituting 97% of the total available inorganic nitrogen. 6255,2003,2,4,Fingerprints of global warming on wild animals and plants,Over the past 100 years| the global average temperature has increased by approximately 0.6 degreesC and is projected to continue to rise at a rapid rate(1). Although species have responded to climatic changes throughout their evolutionary history(2)| a primary concern for wild species and their ecosystems is this rapid rate of change(3). We gathered information on species and global warming from 143 studies for our meta-analyses. These analyses reveal a consistent temperature-related shift| or 'fingerprint'| in species ranging from molluscs to mammals and from grasses to trees. Indeed| more than 80% of the species that show changes are shifting in the direction expected on the basis of known physiological constraints of species. Consequently| the balance of evidence from these studies strongly suggests that a significant impact of global warming is already discernible in animal and plant populations. The synergism of rapid temperature rise and other stresses| in particular habitat destruction| could easily disrupt the connectedness among species and lead to a reformulation of species communities| reflecting differential changes in species| and to numerous extirpations and possibly extinctions. 6267,2003,4,4,Fixation and chemical analysis of single fog and rain droplets,Last decade| the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests| materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively| but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope| and SEX-EDX| particle-induced X-ray emission (PIXE) and micro-PIXE analyses| respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall. (C) 2002 Elsevier Science B.V. All rights reserved. 2775,2003,2,4,Fluctuations of Vanessa cardui butterfly abundance with El Nino and Pacific Decadal Oscillation climatic variables,Annual 4th of July Butterfly Count data spanning more than 20 years are examined to explore Vanessa cardui (Painted Lady) population fluctuations with ENSO (El Nino) and Pacific Decadal Oscillation (PDO) indices. California| Colorado and Nebraska censuses exhibit a strong positive correlation with the strong El Nino events of 1982-1983 and 1997-1998 and the weaker event of 1991-1992. Regression analysis shows the population fluctuations are strongly coupled to climate variations on both short (El Nino) and longer (Pacific Decadal Oscillation) time scales. Recognizing the sensitivity to these time scales is important for predicting longer-term global climate change effects. 6232,2003,4,4,Forest woody biomass classification with satellite-based radar coherence over 900 000 km(2) in Central Siberia,In the current context of global deforestation and global warming| a wide range of organisations| with local to international remits| need estimates of forest biomass to assess the state of the World's forests and their rate of change. The task would be impossible without space-based Earth observation| which allows the rapid generation of extensive data sets describing land surface properties. It is the task of remote sensing scientists to interpret these data into a meaningful source of forest information. Here| a fast and easily automated method for classifying boreal forests in terms of growing stock volume is presented. The work was conducted as part of the SIBERIA project| which has resulted in the recent publication of a map of forest growing stock volume covering 2 900 000 km(2) in Central Siberia. The paper describes the use of satellite-based radar coherence to differentiate categories of forest growing stock volume| the application of this method to classify and map Central Siberian forests| and the characterisation of the forest classes to help in the interpretation. A list of acronyms and abbreviations used in the text is provided in Appendix A. (C) 2002 Elsevier Science B.V. All rights reserved. 6089,2003,3,4,Freonless gas mixtures for glass RPC operated in streamer mode,We have operated successfully glass Resistive Plate Counters (RPC) at the BELLE experiment by using a nonflammable gas mixture of 30% argon| 8% butane-silver and 62% freon| HFC-134a. This freon is nonozone depleting freon| but a freon has a high global warming potential in general. Thus a gas mixture for RPC might be desired to be freonless in the near future. We have tested the performance of glass RPC operated in streamer mode with a nonfreon gas mixture of argon| butane| CO2 and/or O-2 gases| and found an efficiency of about 90%. (C) 2003 Elsevier Science B.V. All rights reserved. 5980,2003,3,3,From mine to refrigeration: a life cycle inventory analysis of the production of HFC-134a,A life cycle inventory analysis has been conducted for the production of HFC-134a (1|1|1|2-tetrafluoroethane| CH2FCF3)(1) through from basic raw materials (crude oil| natural gas| sulphur and fluorspar) to the pure product delivered to industrial customers. The analysis was based on real industrial operations in Japan| USA and UK. It showed that production required limestone| water and transition metal catalysts| in addition to the basic raw materials| and that the energy required to provide these raw materials in a form that can be used at the plants and to process them through intermediates into HFC-134a is the equivalent of 4.52 tonnes of CO2 per tonne of product. Environmental releases associated with HFC-134a included waste salt brine (to the sea)| mine tailings (mainly "country" rock landfilled at the mine) and small quantities of calcium sulphate and spent catalyst (both sent to landfill). In addition| greenhouse gases amounting to the equivalent of 2.1 tonnes of CO2 per tonne of product were emitted to the atmosphere from the plants studied| an effect very much smaller than that estimated in previous studies mainly because the real release rates from current processes are very much less than those assumed in prior work. The global warming potential(2) of HFC-134a is 1300| meaning that| during the first 100 years following the release of one tonne| the effect on climate change is equivalent to 1300 tonnes of carbon dioxide. Consequently| the 6.6 tonnes of carbon dioxide equivalent| emitted during production in the form of energy required and other greenhouse gases| is of relatively little importance and the key requirement to reduce environmental impact is containment during use. (C) 2003 Elsevier Ltd and IIR. All rights reserved. 2813,2003,3,4,From the atomic age to the solar age,One of the most important decisions taken in energy policy in recent years is the "Act on the Planned Termination of the Use of Nuclear Power for Industrial Generation of Electricity." A technology incorporating the hazard of catastrophic accidents| environmental pollution| and detrimental consequences to health| as well as the open question of managing radioactive waste| is not fit for the future. This turnaround in energy policy marks the beginning of the required entry into the solar age. Changing our energy supply is necessary in the light of the threatening scenarios of global climate change and the finite nature of fossil sources of energy| and needs a clear political dimension. The framework conditions to be established by politics for a sustainable power economy thus rest on three pillars: Expansion of renewable energy sources| improvement of energy efficiency| an ddecentralized structures in energy supply. The success of our national energy policy also offers incentives to other countries and for exports. At EU level| important decisions in the interest of the consumer must be supported. 6024,2003,3,3,Fuel consumption-derived CO2 emissions under conventional and reduced tillage cropping systems in northern Japan,In the context of their role in net global warming| CO2 emissions were calculated for fuel-consuming processes associated with arable land crop production in Hokkaido| northern Japan. Fuel-consuming processes included tractor-based field operations| transportation of products and materials and grain drying. In conventional tillage (CT) systems| total CO2 emissions from fuel consumption were 826.2| 605.4| 424.2 and 738.7 kg CO2 ha(-1) for winter wheat (Triticum aestivum L.)| sugar beet (Beta vulgaris L.)| adzuki bean (Vigna angularis (Willd.) Ohwi and Ohashi) and potato (Solanum tuberosum L.) production| respectively. In winter wheat production| 55% of total CO2 emission were released from kerosene and electricity use for grain drying| the remainder from tractor-based field operations. In contrast| for sugar beet| adzuki bean and potato production| field operations were the main contributors to CO2 emissions. Of the field operations| tillage and harvesting required the largest amounts of fuels. Under reduced tillage (RT) systems in which soil preparation in early spring was reduced and plowing after harvesting was omitted| 47.51 ha(-1) of diesel oil equivalent to 125.4 kg CO2 ha(-1) could be saved| regardless of crop species. Consequently| total CO2 emissions could be reduced by 15-29%| respectively| in winter wheat and adzuki bean production. In the Tokachi region of Hokkaido| a primary arable crop production region in Japan| annual CO2 emissions under CT and RT for the four crops produced were estimated at 82.7 Gg CO2 per year and 67.4 Gg CO2 per year| respectively. Besides reduced fuel costs| the use of RT production systems could significantly reduce the large quantities Of CO2 released as a result of arable land crop production in northern Japan. (C) 2003 Elsevier Science B.V. All rights reserved. 6013,2003,3,4,Gasification and combustion behavior of combustibles injected into coke bed,From the viewpoint of preventing global warming and reducing maintenance costs| the reduction of coke consumption in the direct melting furnace for municipal solid waste is strongly called for. Accordingly| the authors have developed technology for injecting combustibles through the tuyeres of the direct melting furnace. This paper reports on the gasification and combustion behavior of combustibles injected into coke bed in a high-temperature combustion experiment. The main results obtained are as follows: (1) Combustibles such as plastics| combustible dust and LPG injected through tuyeres gasify and burn with priority over coke even under the combustion conditions of a direct melting furnace that has no raceway space. (2) Combustible injection through tuyeres is effective in reducing the coke consumption in the direct melting furnace. 6278,2003,3,3,Generation and transmission prospects for solar electricity: UK and global markets,World energy demands are assumed to double within the next 20 years. Fossil fuels are being depleted at a faster rate than ever before. Global warming and its associated climatic change are becoming serious concerns for governments worldwide. There is| thus| an urgent need for much more efficient and environmentally friendly energy resources to be exploited worldwide. Renewable energy is the solution to these challenges. Solar photovoltaic (PV) energy| is an elegant and effective renewable energy resource that is increasingly being seen as a promising candidate for provision of clean and sustainable power. Using up to 20 years of measured solar radiation data from seven widespread UK locations| the feasibility of interconnected| solar powered communities has been presently undertaken. This study has also explored the long term prospects of large scale PV generation in arid/semi-arid locations| around the globe and its transmission using hydrogen as the energy vector. It is estimated that a single solar PV station of 250 x 250 km(2) area| or 12 decentralised stations each of 72 x 72 km(2) area would be sufficient to meet the year 2020 world electricity demand. Presently| closer attention is paid towards the feasibility of supply of hydrogen from arid/semi-arid regions to meet partially the year 2020 electrical demand. For OECD-Europe| a modular approach is proposed. Estimates show that a 9 x 9 km(2) PV array area would be sufficient to provide a flow rate of 11.5 kg/s of hydrogen through a 2 m diameter pipeline| which translates to an annual capacity of 9 TW h. Because of the low density of hydrogen| compared to natural gas| staged pumping would be required only after a distance of over 3000 km. (C) 2002 Elsevier Science Ltd. All rights reserved. 6124,2003,2,4,Genetic variation and phenotypic plasticity of Quercus robur populations and open-pollinated families in Lithuania,The purpose of the study was to estimate among- and within-population variation for juvenile growth and for growth rhythm traits| bud flushing and leaf colouring| in open-pollinated families of Quercus robur L. from six Lithuanian populations under different environmental conditions. Assessments were done in the nursery up to 4 yrs| and after replanting in three field trials at the age of 6 yrs. A highly significant population effect was found for bud flushing. Large family variance components were estimated for bud flushing and height. The familyxsite interaction was significant and more pronounced for growth cessation and height than for bud flushing. Depending on the trait| from 13 to 33% of families contributed significantly to the familyxsite interaction. Strongly significant sitexpopulation interaction was estimated only for bud flushing. Families with early bud flushing were taller| although the correlation was weak. Correlations between family means in bud flushing and bud flushing of parent trees varied from 0.53 to 0.60. Large CV A estimates for the adaptive traits suggest that species have a potential to adapt to environmental changes that may occur from global warming and indicate good perspectives for gene conservation and tree breeding when using Multiple Population Breeding System. 6106,2003,2,4,Geochemical evidence of rapid hydrocarbon venting from a seafloor-piercing mud diapir| Gulf of Mexico continental shelf,A research submersible was employed to collect sediments from a previously undescribed diapiric mud mound on the Gulf of Mexico continental shelf. The sediments contain high concentrations Of C-1-C6+ hydrocarbon gases and crude oil. The mud mound hydrocarbons are relatively unaffected by biodegradation| in contrast to the heavily biodegraded hydrocarbons that characterize the sediments of some other Gulf of Mexico seep sites| including those colonized by chemosynthetic communities. The molecular and isotopic properties of the gas and oil suggest rapid hydrocarbon transport from the mound sediments to the water column. The mud mound is an episodic point source of an oil slick on the sea surface. Gas venting is observed on the seafloor| and bubble trains recorded close to the sea surface suggest that greenhouse thermogenic gases (mainly methane) may escape to the atmosphere. Improved understanding of the fate Of C-1-C6+ gases and crude oil in shallow marine sediments will contribute to better assessment of the impact of seep hydrocarbons on the global inventory of atmospheric sources. (C) 2003 Elsevier Science B.V. All rights reserved. 2743,2003,5,4,Glacial North Atlantic: Sea-surface conditions reconstructed by GLAMAP 2000,The response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in paleoclimatology. Our new reconstruction of peak glacial sea surface temperatures (SSTs) in the Atlantic is based on census counts of planktic foraminifera| using the Maximum Similarity Technique Version 28 (SIMMAX-28) modern analog technique with 947 modern analog samples and 119 well-dated sediment cores. Our study compares two slightly different scenarios of the Last Glacial Maximum (LGM)| the Environmental Processes of the Ice Age: Land| Oceans| Glaciers (EPILOG)| and Glacial Atlantic Ocean Mapping (GLAMAP 2000) time slices. The comparison shows that the maximum LGM cooling in the Southern Hemisphere slightly preceeded that in the north. In both time slices sea ice was restricted to the north western margin of the nordic seas during glacial northern summer| while the central and eastern parts were ice-free. During northern glacial winter| sea ice advanced to the south of Iceland and Faeroe. In the central northern North Atlantic an anticyclonic gyre formed between 45degrees and 60degreesN| with a cool water mass centered west of Ireland| where glacial cooling reached a maximum of >12degreesC. In the subtropical ocean gyres the new reconstruction supports the glacial-to-interglacial stability of SST as shown by CLIMAP Project Members (CLIMAP) [1981]. The zonal belt of minimum SST seasonality between 2degrees and 6degreesN suggests that the LGM caloric equator occupied the same latitude as today. In contrast to the CLIMAP reconstruction| the glacial cooling of the tropical east Atlantic upwelling belt reached up to 6degrees-8degreesC during Northern Hemisphere summer. Differences between these SIMMAX-based and published U37(k)- and Mg/Ca-based equatorial SST records are ascribed to strong SST seasonalities and SST signals that were produced by different planktic species groups during different seasons. 2801,2003,2,4,Global amphibian declines: sorting the hypotheses,Reports of malformed amphibians and global amphibian declines have led to public concern| particularly because amphibians are thought to be indicator species of overall environmental health. The topic also draws scientific attention because there is no obvious| simple answer to the question of what is causing amphibian declines? Complex interactions of several anthropogenic factors are probably at work| and understanding amphibian declines may thus serve as a model for understanding species declines in general. While we have fewer answers than we would like| there are six leading hypotheses that we sort into two classes. For class I hypotheses| alien species| over-exploitation and land use change| we have a good understanding of the ecological mechanisms underlying declines; these causes have affected amphibian populations negatively for more than a century. However| the question remains as to whether the magnitude of these negative effects increased in the 1980s| as scientists began to notice a global decline of amphibians. Further| remedies for these problems are not simple. For class II hypotheses| global change (including UV radiation and global climate change)| contaminants and emerging infectious diseases we have a poor| but improving understanding of how each might cause declines. Class II factors involve complex and subtle mechanistic underpinnings| with probable interactions among multiple ecological and evolutionary variables. They may also interact with class I hypotheses. Suspected mechanisms associated with class II hypotheses are relatively recent| dating from at least the middle of the 20th century. Did these causes act independently or in concert with pre-existing negative forces of class I hypotheses to increase the rate of amphibian declines to a level that drew global attention? We need more studies that connect the suspected mechanisms underlying both classes of hypotheses with quantitative changes in amphibian population sizes and species numbers. An important step forward in this task is clarifying the hypotheses and conditions under which the various causes operate alone or together. 6161,2003,4,4,Global atmospheric black carbon inferred from AERONET,AERONET| a network of well calibrated sunphotometers| provides data on aerosol optical depth and absorption optical depth at >250 sites around the world. The spectral range of AERONET allows discrimination between constituents that absorb most strongly in the UV region| such as soil dust and organic carbon| and the more ubiquitously absorbing black carbon (BC). AERONET locations| primarily continental| are not representative of the global mean| but they can be used to calibrate global aerosol climatologies produced by tracer transport models. We find that the amount of BC in current climatologies must be increased by a factor of 2-4 to yield best agreement with AERONET| in the approximation in which BC is externally mixed with other aerosols. The inferred climate forcing by BC| regardless of whether it is internally or externally mixed| is approximate to1 W/m(2)| most of which is probably anthropogenic. This positive forcing (warming) by BC must substantially counterbalance cooling by anthropogenic reflective aerosols. Thus| especially if reflective aerosols such as sulfates are reduced| it is important to reduce BC to minimize global warming. 2729,2003,2,4,Global climate change and mammalian species diversity in US national parks,National parks and bioreserves are key conservation tools used to protect species and their habitats within the confines of fixed political boundaries. This inflexibility may be their "Achilles' heel" as conservation tools in the face of emerging global-scale environmental problems such as climate change. Global climate change| brought about by rising levels of greenhouse gases| threatens to alter the geographic distribution of many habitats and their component species. With these changes comes great uncertainty about the future ability of parks and protected areas to meet their conservation mandates. We report here on an analysis aimed at assessing the extent of mammalian species turnover that may be experienced in eight selected U.S. national parks if climate change causes mammalian species within the continental U.S. to relocate to new geographic locations. Due to species losses of up to 20% and drastic influxes of new species| national parks are not likely to meet their mandate of protecting current biodiversity within park boundaries. This approach represents a conservative prognosis. As species assemblages change| new interactions between species may lead to less predictable indirect effects of climate change| increasing the toll beyond that found in this study. 2755,2003,2,4,Global climate change and reindeer: effects of winter weather on the autumn weight and growth of calves,Reindeer/caribou (Rangifer tarandus)| which constitute a biological resource of vital importance for the physical and cultural survival of Arctic residents| and inhabit extremely seasonal environments| have received little attention in the global change debate. We investigated how body weight and growth rate of reindeer calves were affected by large-scale climatic variability [measured by the North Atlantic Oscillation (NAO) winter index] and density in one population in central Norway. Body weights of calves in summer and early winter| as well as their growth rate (summer to early winter)| were significantly influenced by density and the NAO index when cohorts were in utero. Males were heavier and had higher absolute growth than females| but there was no evidence that preweaning condition of male and female calves were influenced differently by the NAO winter index. Increasing NAO index had a negative effect on calves' body weight and growth rate. Increasing density significantly reduced body weight and growth rate of calves| and accentuated the effect of the NAO winter index. Winters with a higher NAO index are thus severe for reindeer calves in this area and their effects are associated with nutritional stress experienced by the dams during pregnancy or immediately after calving. Moreover| increased density may enhance intra-specific competition and limits food available at the individual level within cohorts. We conclude that if the current pattern of global warming continues| with greater change occurring in northern latitudes and during winter as is predicted| reduced body weight of reindeer calves may be a consequence in areas where winters with a high NAO index are severe. This will likely have an effect on the livelihood of many northern indigenous peoples| both economically and culturally. 2723,2003,2,3,Global estimation of crop productivity and the impacts of global warming by GIS and EPIC integration,In this paper| a new methodology for global estimation of crop productivity is proposed. This methodology integrates Erosion Productivity Impact Calculator (EPIC) model with Geographic Information System (GIS) and Inference Engine (IE) technique. EPIC was developed by USDA to analyze the relationship between soil erosion and agricultural productivity just at field level. With the integration of GIS| EPIC can be extended to the application of global or regional level. In this integration| IE is developed to determine possible crop combinations| the optimum starting and ending dates of growth cycle for each crop type and grid cell| in order to ensure best possible crop yields for both rain-fed and irrigated conditions. A case of global crop productivity estimation is tested with GIS-based EPIC in 2000. National averages are computed to be comparable to yields in FAO statistics. The comparison indicates that the GIS-based EPIC is able to simulate crop productivity at global level. In addition| with the global climate change data provided by the Intergovernment Panel on Climate Change (IPCC) from the first version of the Canadian Global Coupled Model (CGCM1)| GIS-based EPIC is run for scenarios of future climate in the year of 2010| 2020| 2030| 2040| and 2050 to predict the effects of global warming on main crop yields. Results show the global warming will be harmful for most of the countries| and an efficient adaptation to alternative climates tends to reduce the damages. (C) 2003 Elsevier Science B.V. All rights reserved. 6296,2003,3,3,Global influences on rangelands of Australia,Globalisation is a key pressure affecting the current and future use of the rangelands of Australia. While primary producers often perceive an insatiable demand for food as a guarantee of business success| declining population growth rates and high levels of productivity improvement in world food production are reducing the importance of food and fibre from the rangelands. This| combined with significant changes in consumer demands| is driving rangeland producers to meet market specifications for quality| safety| animal welfare and sustainability. Sustainability is a particular challenge with the rangelands certain to be affected by global warming and the politics and strategies required to reduce greenhouse gas emissions. Currently the rangelands produce a higher proportion of greenhouse gases compared with their contribution to the economy. However| they also provide an opportunity for carbon sequestration. While international trade liberalisation has been of advantage to the grazing industries in the rangelands| increased global awareness of the Australian rangelands| facilitated by the communications revolution| is encouraging alternative uses including tourism| existence value and other conservation and biodiversity management uses. The growing concept of multi-functionality will also impact on the rangelands as international government programs continue to encourage non-commercial| surplus production of food. These influences are forcing major changes in the way land is used and what it produces. 6026,2003,5,3,Global methane emission through mud volcanoes and its past and present impact on the Earth's climate,Mud volcanism is an abundant| global phenomenon whereby fluid-rich| low-density sediments extrude both on land and offshore. Methane| which generally exceeds 90 vol% of the gas phase| is emitted at high rates during and after emplacement of the mud domes and is known for its high global warming potential (GWP). This comprehensive estimate of the annual contribution of mud volcano degassing assesses the significance of mud volcanism for the accumulation of greenhouse gases in the atmosphere. A first-order estimate for the earlier| pre-anthropogenic volume of methane released through mud volcanoes further supports their profound effect on the Earth's climate since at least the Paleozoic (570 Ma). 6018,2003,2,4,Global potential soil erosion with reference to land use and climate changes,A GIS-based RUSLE model is employed to study the global soil erosion potential for viewing the present situation| analysing changes over the past century| and projecting future trends with reference to global changes in land use and climate. Scenarios considered in the study include historical| present and future conditions of cropland and climate. This research gives the first overview of the global situation of soil erosion potential considering the previous century as well as the present and future. Present soil erosion potential is estimated to be about 0.38 mm year(-1) for the globe| with Southeast Asia found to be the most seriously affected region in the world. It is estimated that nearly 60% of present soil erosions are induced by human activity. With development of cropland in the last century| soil erosion potential is estimated to have increased by about 17%. Global warming might significantly increase the potential for soil erosion| and the regions with the same increasing trend of precipitation and population might face much more serious problems related to soil erosion in the future. Copyright (C) 2003 John Wiley Sons| Ltd. 6088,2003,2,3,Global warming and potential changes in fish habitat in US streams,To project potential habitat changes of 57 fish species under global warming| their suitable thermal habitat at 764 stream gaging stations in the contiguous United States was studied. Global warming was specified by air temperature increases projected by the Canadian Centre of Climate Modelling General Circulation Model for a doubling of atmospheric CO2. The aquatic thermal regime at each gaging station was related to air temperature using a nonlinear stream temperature/air temperature relationship. Suitable fish thermal habitat was assumed to be constrained by both maximum temperature and minimum temperature tolerances. For cold water fishes with a 0degreesC lower temperature constraint| the number of stations with suitable thermal habitat under a 2 x CO2 climate scenario is projected to decrease by 36%| and for cool water fishes by 15%. These changes are associated with a northward shift of the range. For warm water fishes with a 2degreesC lower temperature constraint| the potential number of stations with suitable thermal habitat is projected to increase by 31%. 6100,2003,2,4,Global warming and the demand for water,More than a decade has passed since the International Panel on Climatic Change began to study (in depth) the possibility that the global climate was changing. Increasing attention is also being paid to the impact of such changes on society in general| and on the planning and management of water resources. Not least among the water resources planning problems is the estimation of the changes which might occur in public water-supply demands. Such changes are notoriously difficult to evaluate| particularly in the UK where most domestic premises remain un-metered. Elsewhere| econometric models involving climatic parameters as independent variables have had some success| but a recent application of this approach in the UK was unable to identify particular parameters which had a consistent influence over the summer period. This lack of success might be partly caused by the public reaction to summer conditions being a complex function of several parameters| such as duration of sunshine| temperature and rainfall. This complexity has already been recognised by climatologists| who have devised forms of summer indices involving weighted combinations of climatic variables to determine how 'good' or 'bad' a particular period might be perceived by the general public. The use of one such summer index to explain the variations in an index of demand for public water supply in the London supply area has shown that simple and consistent relationships can be derived. Application of these relationships to scenarios of changes in temperature| sunshine duration and rainfall totals for the year 2050 shows an increase of 0.6- 2.9 index points in water-supply demand over the 1950-1990 period average. 6251,2003,2,3,Global warming and the export of dissolved organic carbon from boreal peatlands,Peatlands occupy approximately 15% of boreal and sub-arctic regions| contain approximately one third of the world's soil carbon pool| and supply most of the dissolved organic carbon (DOC) entering boreal lakes and rivers and the Arctic Ocean. The high latitudes occupied by these peatlands are expected to see the greatest amount of climatic warming in the next several decades. In addition to increasing temperatures| climatic change could also affect the position of the water-table level and discharge from these peatlands. Changes in temperature| water tables| and discharge could affect delivery of DOC to downstream ecosystems where it exerts significant control over productivity| biogeochemical cycles| and attenuation of visible and UV radiation. We experimentally warmed and controlled water tables while measuring discharge in a factorial experiment in large mesocosms containing peat monoliths and intact plant communities from a bog and fen to determine the effects of climate change on DOC budgets. We show that the DOC budget is controlled largely by changes in discharge rather than by any effect of warming or position of the water-table level on DOC concentrations. Furthermore| we identify a critical discharge rate in bogs and fens for which the DOC budget switches from net export to net retention. We also demonstrate an exponential increase in trace gas CO2-C and CH4-C emissions coincident with increased retention of dissolved organic carbon from boreal peatlands. 6046,2003,2,3,Global warming and thermohaline circulation stability,The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC| including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe| including a cooling throughout the Northern Hemisphere| which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics| the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming| and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However| there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however| some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual| modelling and observational uncertainties| but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future. 6021,2003,4,4,Global warming trend of mean tropospheric temperature observed by satellites,We have analyzed the global tropospheric temperature for 1978 to 2002 with the use of passive microwave sounding data from the NOAA series of polar orbiters and the Earth Observing System Aqua satellite. To accurately retrieve the climatic trend| we combined the satellite data with an analytic model of temperature that contains three different time scales: a linear trend and functions that de. ne the seasonal and diurnal cycles. Our analysis shows a trend of +0.22degrees to 0.26degreesC per 10 years| consistent with the global warming trend derived from surface meteorological stations. 6188,2003,4,4,Global warming versus ozone depletion: failure and success in North America,The success of ozone depletion as a social problem is used to examine and understand the relative failure of global warming. Starting with the (aborted) 'hot crisis' of the Greenhouse summer of 1988| this paper tries to show why| despite dire scientific warning| advantages in claims-making| and the perceived emergence of strange weather| global warming consistently obtained lesser outcomes. Whereas global warming is a complex and uncertain scientific issue| the ozone hole was associated and resonated with easy-to-understand bridging metaphors derived from the popular culture. The latter problem not only gave rise to a hot crisis| but was also caught up in a cultural whirlwind-a rapidly evolving and progressive sequence of dynamic and often surprising events that surge through a variety of public arenas with a strong conversational and practical presence. Effectively| ozone loss provided a sense of concrete risk with both strong emotional overtones and everyday relevance for talk and action. Global warming| in contrast| is not amenable to bridging metaphors and did not lend itself to a cultural whirlwind. 5974,2003,3,3,Global warming| uncertainty and endogenous technical change,What impact does ecological uncertainty have on agents' decisions concerning domestic emissions abatement| physical investments| and R&D expenditures? How sensitive are the answers to these questions when we move from exogenous to endogenous technical change? To investigate these issues we modify the ETC-RICE model described in Buonanno et al. ( 2001) by embedding in it a hazard rate function as in Bosello and Moretto ( 1999). With this model at hand we run numerical optimisations focusing our attention on the control variables of the representative agents| i.e.| domestic abatement rate| investments in physical capital| and R&D spending| as well as on the endogenous patterns of GDP level and CO2 emissions. Our results show that uncertainty strongly influences agents behaviour; in particular| agents slow down their emissions in order to maintain a more sustainable growth path. In addition| R&D expenditures trigger the "engine of growth" exclusively when environmental technical change is formalized in an endogenous fashion. However| even if environmental uncertainty may stimulate technical change| long-run growth it turns out to be negatively affected by the former| as also predicted by Clarke and Reed ( 1994) Tsur and Zemel (1996) and Bosello and Moretto (1999). 6203,2003,2,7,Global warming: Are we confusing cause and effect?,The writers show that the present-day global warming is not due to the increase in the volume of greenhouse gases| but rather to the increased solar activity. It appears that we are at the rising phase of the latest 80-90 year cycle of the solar activity. At the present time| there is no sound justification for the cut in the man-induced carbon dioxide emission as required by the Kyoto Protocol of 1997. The rising global temperature drives large volumes of CO2 from the ocean water into the atmosphere. Thus "cause" and "effect" of global warming phenomenon are misunderstood by many scientists.
5996,2003,2,4,Grassland responses to three years of elevated temperature| CO(2)| precipitation| and N deposition,Global climate and atmospheric changes may interact in their effects on the diversity and composition of natural communities. We followed responses of an annual grassland to three years of all possible combinations of experimentally elevated CO(2) (+300| muL/L)| warming (+80 W/m(2)| + similar to1degreesC)| nitrogen deposition (+7 g N.m(-2).yr(-1))|and precipitation (+50%). Responses of the 10 most common plant species to global changes and to interannual variability were weak but sufficiently consistent within functional groups to drive clearer responses at the functional group level. The dominant functional groups (annual grasses and forbs) showed distinct production and abundance responses to individual global changes. After three years| N deposition suppressed plant diversity| forb production| and forb abundance in association with enhanced grass production. Elevated precipitation enhanced plant diversity| forb production| and forb abundance but affected grasses little. Warming increased forb production and abundance but did not strongly affect diversity or grass response. Elevated CO(2) reduced diversity with little effect on relative abundance or production of forbs and grasses. Realistic combinations of global changes had small diversity effects but more marked effects on the relative dominance of forbs and grasses. The largest change in relative functional group abundance (+50% forbs) occurred under the combination of elevated CO(2) + warming + precipitation| which will likely affect much of California in the future. Strong interannual variability in diversity| individual. species abundances| and functional group abundances indicated that in our system| (1) responses after three years were not constrained by lags in community response| (2) individual species were more sensitive to interannual variability and extremes than to mean changes in environmental and resource conditions| and (3) simulated global changes interacted with interannual variability to produce responses of varying magnitude and even direction among years. Relative abundance of forbs| the most speciose group in the community| ranged after three years from >30% under elevated CO(2) + warming + precipitation to <12% under N deposition: While opposing production responses at the ecosystem level by different functional groups may buffet responses such as net primary production (NPP) change| these shifts in relative dominance could influence ecosystem processes such as nutrient cycling and|NPP via differences between grasses and forbs in tissue chemistry| allocation| phenology| and productivity. 6287,2003,3,3,Greenhouse gas emissions and soil indicators four years after manure and compost applications,Understanding how carbon| nitrogen| and key soil attributes affect gas emissions from soil is crucial for alleviating their undesirable residual effects that can linger for years after termination of manure and compost applications. This study was conducted to evaluate the emission Of soil CO2| N2O| and CH4 and soil C and N indicators four years after manure and compost application had stopped. Experimental plots were treated with annual synthetic N fertilizer (FRT)| annual and biennial manure (MN1 and MN2| respectively)| and compost (CP1 and CP2| respectively) from 1992 to 1995 based on removal of 151 kg N ha(-1) yr(-1) by continuous corn (Zea mays L.). The control (CTL) plots received no input. After 1995| only the FRT plots received N fertilizer in the spring of 1999. In 1999| the emissions Of CO2 were similar between control and other treatments. The average annual carbon input in the CTL and FRT plots were similar to soil CO2 C emission (4.4 and 5.1 Mg C ha(-1) yr(-1)| respectively). Manure and compost resulted in positive C and N balances in the soil four years after application. Fluxes of CH4-C and N2O-N were nearly zero| which indicated that the residual effects of manure and compost four years after application had no negative influence on soil C and N storage and global warming. Residual effects of compost and manure resulted in 20 to 40% higher soil microbial biomass C| 42 to 74% higher potentially mineralizable N| and 0.5 unit higher pH compared with the FRT treatment. Residual effects of manure and compost on CO2| N2O| and CH4 emissions were minimal and their benefits on soil C and N indicators were more favorable than that of N fertilizer. 6163,2003,3,4,Greenhouse gas implications of household energy technology in Kenya,Linkages between household energy technology| indoor air pollution| and greenhouse gas (GHG) emissions have become increasingly important in understanding the local and global environmental and health effects of domestic energy use. We report on GHG emissions from common Kenyan wood and charcoal cookstoves. Our estimations are based on 29 d of measurements under the conditions of actual use in 19 rural Kenyan households. Carbon monoxide (CO)| particulate matter (PM10)| combustion phase| and fuel mass were measured continuously or in short intervals in day-long monitoring sessions. Emissions of pollutants other than CO and PM10 were estimated using emissions ratios from published literature. We estimated that the daily carbon emissions from charcoal stoves (5202 +/- 2257 g of C: mean SO) were lower than both traditional open fire (5990 +/- 1843 g of C) and improved ceramic woodstoves (5905 +/- 1553 g of C)| but the differences were not statistically significant. However| when each pollutant was weighted using a 20-yr global warming potential| charcoal stoves emitted larger amounts of GHGs than either type of woodstove (9850 +/- 4600 g of C for charcoal as compared to 8310 +/- 2400 and 9649 +/- 2207 for open fire and ceramic woodstoves| respectively; differences not statistically significant). Non-CO2 emissions from charcoal stoves were 5549 +/- 2700 g of C in 20-yr CO2 equivalent units| while emissions were 2860 +/- 680 and 4711 +/- 919 for three-stone fires and improved ceramic stoves| respectively| with statistically significant results between charcoal and wood stoves. Therefore in a sustainable fuel-cycle (i.e.| excluding CO2)| charcoal stoves have larger emissions than woodstoves. When the emissions from charcoal production| measured in a previous study| were included in the assessment| the disparity between the GHG emissions from charcoal and firewood increased significantly| with non-CO2 GHG emissions factors (g of C/kg of fuel burned) for charcoal production and consumption 6-13 times higher than emissions from woodstoves. Policy implications and options for environment and public health are discussed. 2749,2003,2,3,Growth and biomass allocation of shrub and grass seedlings in response to predicted changes in precipitation seasonality,Anthropogenic emissions contribute to an annual 0.5% increase in atmospheric CO2. As global CO2 levels increase| regional precipitation patterns will likely be altered. Our primary objective was to determine whether a reduction in summer precipitation or an increase in winter/spring precipitation| predicted by global climate change models| will favor the establishment of C-4 grasses or C-3 shrubs in southern savannas. Our secondary objective was to determine how defoliation and microsite light availability interact with altered precipitation regimes to influence grass and shrub seedling growth and biomass allocation patterns. Seedlings of 3 shrub species (Prosopis glandulosa var. glandulosa| Acacia berlandieri| and A. greggii var. wrightii) and 3 grass species (Aristida purpurea var. wrightii| Setaria texana| and Stipa leucotricha) were watered based on probable changes in precipitation in a CO2 enriched atmosphere (0.6| 0.8| and 1.0 current ambient summer precipitation and 1.0| 1.15| and 1.30 current winter/spring precipitation). Seedlings were defoliated at 3 levels (non-defoliated| single defoliation| and repeated defoliation) within 2 levels of microsite light availability (100 and 50% ambient). Defoliation significantly reduced total shrub and grass seedling biomass. Reducing light availability decreased shrub seedling root: shoot ratio| but total biomass was not significantly affected. Grass seedling biomass and root: shoot ratio decreased when light availability was reduced. Changing the seasonality of precipitation by reducing summer rainfall or increasing winter/spring rainfall did not significantly influence growth or biomass allocation of grass and shrub seedlings in a semiarid savanna. Microsite variations in defoliation intensity and light availability influence seedling growth and biomass allocation more than changing seasonality of precipitation. Shrub and grass seedling establishment and growth on semiarid rangelands are already limited by summer precipitation| so a further reduction as proposed by climate change models will have a limited impact on seedling dynamics. 6030,2003,2,4,Has coral bleaching delayed our understanding of fundamental aspects of coral-dinoflagellate symbioses?,Tropical reef corals are ecologically important examples of mutualistic symbioses whose success is defined by the interwoven biologies of their symbiotic partners. These associations are exquisitely regulated| yet the equilibrium is sensitive to environmental disturbances| which cause a breakdown in symbiotic communication| loss of algae from the host| concomitant paling of coral coloration known as coral bleaching| and| if the conditions persist| death of the coral. Faced with the prospect of catastrophic coral mortality associated with global warming and related environmental shifts| researchers have focused their efforts on coral bleaching; although significant progress has been made in this area| understanding of the basic biology of these associations remains poor. Here we discuss several issues that have potentially contributed to this knowledge gap and conclude that without a sound understanding of the basic biology of these important symbioses| it will be very difficult to elucidate the mechanisms that drive coral bleaching. 6007,2003,4,4,High-resolution simulations of global climate| part 2: effects of increased greenhouse cases,We report results from the highest-resolution simulations of global warming yet performed with an atmospheric general circulation model. We compare the climatic response to increased greenhouse gases of the National Center for Atmospheric Research (NCAR) climate model| CCM3| at T42 and T170 resolutions (horizontal grid spacing of 300 and 75 km respectively). All simulations use prescribed sea surface temperatures (SST). Simulations of the climate of 2100 AD use SSTs based on those from NCAR coupled model| Climate System Model (CSM). We find that the global climate sensitivity and large-scale patterns of climate change are similar at T42 and T170. However| there are important regional scale differences that arise due to better representation of topography and other factors at high resolution. Caution should be exercised in interpreting specific features in our results both because we have performed climate simulations using a single atmospheric general circulation model and because we used with prescribed sea surface temperatures rather than interactive ocean and sea-ice models. 6290,2003,2,4,Historical distribution and abundance of Phragmites australis at Long Point| Lake Erie| Ontario,Recent expansion of Phragmites australis throughout many Great Lakes wetlands has caused concern among resource managers because it is thought to degrade waterfowl habitat and reduce biodiversity. Wetlands at Long Point| Lake Erie| have some of the most important habitats for staging waterfowl on the Great Lakes and anecdotal evidence suggests that Phragmites has been expanding rapidly in some of these wetlands. To make informed management decisions| a better understanding of historical changes in distribution and abundance of this species is needed| as well as the ability to identify which plant species/communities Phragmites is replacing. Long Point's wetland communities were digitally mapped from aerial photographs from 1945 to 1999. The aerial extent of Phragmites stands was measured by digitizing vegetation boundaries| ground-truthing| and analyzing the data using a GIS. A geometric growth formula was used to determine the intrinsic rate of change of Phragmites over time. Phragmites abundance fluctuated throughout the period (1945: 4 ha; 1955: 7.7 ha; 1964: 69 ha; 1968: 3.6 ha; 1972: 15.1 ha; 1978: 17.7 ha; 1985: < 4 ha; 1995: 18 ha; 1999: 137 ha)| but its abundance increased exponentially between 1995 and 1999 (137 ha; intrinsic rate of growth in area = +0.50/yr). The species/communities that were most often replaced by Phragmites between 1995 and 1999 were Typha spp. (33.8%)| marsh meadow (31%)| sedge/grass hummock (10.8%)| and other mixed emergents (9.6%). Of 31 stands analyzed within the study area| 28 (90%) were of a non-native strain of Phragmites australis (haplotype M) that has been rapidly expanding throughout the Atlantic region of the United States. We suggest that the recent rapid expansion of Phragmites at Long Point is the direct result of this exotic invasion| and that it has been facilitated by both declines in Great Lakes water levels and increases in ambient air temperatures; anthropogenic and natural disturbances have possibly also contributed. Given the invasive nature of the exotic genotype| combined with future global warming predictions| Phragmites probably will continue to rapidly expand throughout lower Great Lakes coastal wetlands. 5978,2003,2,3,Historical evolution of flooding damage on a USA/Quebec River Basin,There is a general belief in the public eye that extreme events such as floods are becoming more and more common. This paper explores this hypothesis by examining the historical evolution of annual expected flooding damage on the Chateauguay River Basin| located at the border between the United States and the province of Quebec| Canada. A database of basin land use was constructed for the years 1930 and 1995 to assess anthropogenic changes and their impact on the basin's hydrology. The progressive modification of the likelihood of a flooding event over the same period was then investigated using homogeneity and statistical tests on available hydrometric data. The evolution of the annual expected flooding damage was then evaluated using a coupled hydrologic/hydraulic simulator linked to a damage analysis model. The simulator and model were used to estimate flooding damage over a wide range of flooding return periods| for conditions prevailing in 1963 and 1995. Results of the analysis reveal the absence of any increasing or decreasing trend in the historical occurrence of flooding events. However| a general increase in the annual expected flooding damage was observed for all studied river sections. This increase is linked to an historical increase in damages for a given flooding event| and is the result of unbridled construction and development within the flood zone. To assess for future trends| this study also examined the potential impacts linked to the anticipated global warming. Results indicate that a significant increase in seasonal flooding events and annual expected flooding damage is possible over the next century. In fact| what is now considered a 100-year flooding event for the summer/fall season could become a ten-year event by the end of this century. This shows that potential future impacts linked to climate change should be considered now by engineers| land planners| and decision makers. This is especially critical if a design return period is part of the decision making process. 2707,2003,5,4,Holocene yellow silt layers and the paleoclimate event of 8200 a BP in Lop Nur| Xinjiang| NW China,Many yellow silt layers have been identified in the Holocene sediments in the last lake of Lop Nur (playa)| Xinjiang| northwestern China. Statistics of drill-hole cores have revealed more than one hundred layers| which exhibit regularity in time sequence. Study has further verified that these yellow silt layers were deposited through eolian processes. The time-frequency distribution diagram shows an obvious peak occurring at about 8200 a B.P.| which is consistent with the dry| windy and cold climate event occurring at 8200 a in other places around the world. Therefore| this event is regarded as a response to the global climate change. 6033,2003,2,4,How important is climate? Effects of warming| nutrient addition and fish on phytoplankton in shallow lake microcosms,1. Climate is changing. Predictions are for at least a 3 degreesC rise in mean temperature in northern Europe over the next century. Existing severe impacts of nutrients and inappropriate fish stocking in freshwater systems remain. 2. Effects of warming by 3 degreesC above ambient| nutrient addition and the presence or absence of sticklebacks Gasterosteus aculeatus were studied in experimental microcosms dominated by submerged plants| mimicking shallow lake ecosystems. 3. Warming had considerably smaller effects on the phytoplankton community than did fish and nutrients. It had very minor effects on chlorophyll a and total phytoplankton biovolume. However| it significantly decreased the biovolumes of Cryptophyceae (a major component in the controls) and Dinophyceae. Contrary to expectation| warming did not increase the abundance of blue-green algae (cyanophytes). Warming decreased the abundances of Cryptomonas erosa ( Cryptophyceae) and Oocystis pusilla (Chlorophycota) and increased those of two other green algae| Tetraedron minimum and Micractinium pusillum. It had no effect on a further 17 species that were predominant in a community of about 90 species. 4. Fish and nutrients| either together or separately| generally increased the crops of most of the 21 abundant species and of the algal groups. Exceptions were for diatoms and chrysophytes| which were very minor components of the communities. Fish| but neither nutrients nor warming| increased the number of species of phytoplankton detected. This was probably through removal of zooplankton grazers| and parallels terrestrial studies where the presence of top predators| by controlling herbivores| leads to increased plant diversity. 5. There was no particular pattern in the taxonomy or biological characteristics of those species affected by the treatments. In particular| there was no link between organism size (a surrogate for many important biological features of phytoplankton species) and the effects of warming| nutrient addition or presence or absence of fish. However| all species were relatively small and potentially vulnerable to grazing. 6. Synthesis and applications. The results suggest that fears of an increasing abundance of cyanophytes with current projections of global warming may be unrealized| at least in shallow unstratified lakes still dominated by macrophytes. However| they emphasize that eutrophication and fish manipulations remain very important impact factors that determine the abundance of phytoplankton and subsequent problems caused by large growths. 6023,2003,2,4,How often can we expect a record event?,This study applies a simple framework for analysing the incidence of record events. A test of this method on the global mean temperature yields results consistent with a global warming| where record-warm events are more frequent than for a stationary series. The record event analysis suggests that the number of record-warm monthly global mean temperatures is higher than expected| and that the number of record events in the absolute monthly maximum and minimum temperatures in the Nordic countries is slightly higher than expected from a null hypothesis of a stationary behaviour. Because the different station series are not strictly independent| it is difficult to resolve whether there is a significant trend in the warmest absolute monthly minimum temperatures in the Nordic countries. The behaviour of the maximum monthly 24 h precipitation is not distinguishable from the null hypothesis that the series consists of independent and identically distributed random variables. 6197,2003,4,2,How positive is the feedback between climate change and the carbon cycle?,Future climate change induced by atmospheric emissions of greenhouse gases is believed to have a large impact on the global carbon cycle. Several offline studies focusing either on the marine or on the terrestrial carbon cycle highlighted such potential effects. Two recent online studies| using ocean-atmosphere general circulation models coupled to land and ocean carbon cycle models| investigated in a consistent way the feedback between the climate change and the carbon cycle. These two studies used observed anthropogenic CO2 emissions for the 1860-1995 period and IPCC scenarios for the 1995-2100 period to force the climate-carbon cycle models. The study from the Hadley Centre group showed a very large positive feedback| atmospheric CO2 reaching 980 ppmv by 2100 if future climate impacts on the carbon cycle| but only about 700 ppmv if the carbon cycle is included but assumed to be insensitive to the climate changed The IPSL coupled climate carbon cycle model simulated a much smaller positive feedback: climate impact on the carbon cycle leads by 2100 to an addition of less than 100 ppmv in the atmosphere. Here we perform a detailed feedback analysis to show that such differences are due to two key processes that are still poorly constrained in these coupled models: first Southern Ocean circulation| which primarily controls the geochemical uptake of CO2 and second vegetation and soil carbon response to global warming. Our analytical analysis reproduces remarkably the results obtained by the fully coupled models. Also it allows us to identify that| amongst the two processes mentioned above| the latter (the land response to global warming) is the one that essentially explains the differences between the IPSL and the Hadley results. 6143,2003,4,3,How to define clean vehicles? Environmental impact rating of vehicles,How to compare the environmental damage caused by vehicles with different fuels and drive trains? This paper describes a methodology to assess the environmental impact of vehicles| using different approaches| and evaluating their benefits and limitations. Rating systems are analysed as tools to compare the environmental impact of vehicles| allowing decision makers to dedicate their financial and non-financial policies and support measures in function of the ecological damage. The paper is based on the "Clean Vehicles" research project| commissioned by the Brussels Capital Region via the BIM-IBGE (Brussels Institute for the Conservation of the Environment) (Van Mierlo et al.| 2001). The Vrije Universiteit Brussel (ETEC) and the Universite Libre de Bruxelles (CEESE) have jointly carried out the workprogramme. The most important results of this project are illustrated in this paper. First an overview of environmental| economical and technical characteristics of the different alternative fuels and drive trains is given. Afterward the basic principles to identify the environmental impact of cars are described. An outline of the considered emissions and their environmental impact leads to the definition of the calculation method| named Ecoscore. A rather simple and pragmatic approach would be stating that all alternative fuelled vehicles (LPG| CNG| EV| HEV| etc.) can be considered as 'clean'. Another basic approach is considering as 'clean' all vehicles satisfying a stringent emission regulation like EURO IV or EEV. Such approaches however don't tell anything about the real environmental damage of the vehicles. In the paper we describe "how should the environmental impact of vehicles be defined?"| including parameters affecting the emissions of vehicles and their influence on human beings and on the environment and "how could it be defined ?"| taking into account the availability of accurate and reliable data. We take into account different damages (acid rain| photochemical air pollution| global warming| noise| etc.) and their impacts on several receptors like human beings (e.g.: cancer| respiratory diseases| etc); ecosystems| or buildings. The presented methodology is based on a kind of Life Cycle Assessment (LCA) in which the contribution of all emissions to a certain damage are considered (e.g. using Exposure-Response damage function). The emissions will include oil extraction| transportation refinery| electricity production| distribution| (Well-to-Wheel approach)| as well as the emission due to the production| use and dismantling of the vehicle (Cradle-to-Grave approach). The different damages will be normalized to be able to make a comparison. Hence a reference value (determined by the reference vehicle chosen) will be defined as a target value (the normalized value will thus measure a kind of Distance to Target). The contribution of the different normalized damages to a single value "EcoScore" will be based on a panel weighting method. Some examples of the calculation of the Ecoscore for different alternative fuels and drive trains will be calculated as an illustration of the methodology. 2793,2003,2,4,How will global climate change affect risks from long-range transport of persistent organic pollutants?,Climate change and climate variability affect risk from contaminants by changing exposure to chemicals| either through the alteration of pathways or through alteration of environmental concentrating mechanisms. The alteration of pathways is affected by changing the balance between transport and deposition. Although the influence of temperature on multimedia partitioning can be modelled successfully| estimating alteration in other climate components such as distribution and form of precipitation provides a much greater challenge. To understand how climate change affects contaminant concentrations| we distinguish two types of environmental concentrating processes-solvent switching and solvent depletion. The first process| which is simply chemical partitioning| runs spontaneously toward equilibrium. This process alone can explain hemispheric-scale distributions of hexachlorocyclohexane| which partitions strongly into water| and high concentrations of organochlorines at the bottom of aquatic foodwebs. The latter process involves the maintenance of contaminant burdens during the loss of solvent| with the aquatic foodweb providing one of the better-known examples. Solvent reducing processes can produce contaminant concentrations well above thermodynamic equilibrium with a number of important examples provided by phase changes in water (freezing| snow melting). These solvent-reducing processes| which are poorly studied| provide some of the best circumstances for climate change to produce alteration in persistent organic pollutants exposure pathways. 6019,2003,2,4,Hydrological regime analysis of the Selenge River basin| Mongolia,Arid and semi-arid regions are very vulnerable to environmental changes. Climate change studies indicate that the environment in such areas will steadily deteriorate with global warming; inland lakes will shrink and desert areas will expand. Mongolia is a landlocked country in north-central Asia that contains a unique ecological system consisting of taiga| steppe| and desert from north to south. The Selenge River basin (280000 km(2)) in northern Mongolia is a semi-arid region underlain by permafrost| between latitudes 46 and 52degreesN| and longitudes 96 and 109degreesE. The issue of sustainable development of the basin is very important owing to its limited natural resources| including fresh water| forest| and rangeland. To examine the water cycle processes in the basin| a hydrological analysis was carried out using a simple scheme for the interaction between the land surface and atmosphere (big-leaf model) coupled to a hydrological model for the period 1988-92 to estimate the hydrological regime of the basin. Annual precipitation in this period averaged 298 mm| ranging from 212 to 352 mm at a 1degrees x 1degrees resolution based on data from 10 gauges| and the estimated annual evapotranspiration averaged 241 turn| ranging between 153 and 300 mm. This indicates that evapotranspiration accounts for the overwhelming majority of the annual precipitation| averaging 81% and ranging between 64 and 96%. The annual potential evapotranspiration in the basin averaged 2009 mm; the ratio of evapotranspiration (actual to potential evapotranspiration) was 0.12 and the wetness index (annual precipitation to potential evapotranspiration) was 0.15. Copyright (C) 2003 John Wiley Sons| Ltd. 2819,2003,5,4,Ice-rafted detritus evidence from Ar-40/Ar-39 ages of individual hornblende grains for evolution of the eastern margin of the Laurentide ice sheet since 43 C-14 ky,During the last glacial interval| the North Atlantic ice sheets expanded and contracted in approximate synchronicity with orbitally forced global climate change. Variation in ice rafted detritus content in North Atlantic marine sediment cores record the waxing and waning of glaciers| as well as the abrupt temperature changes at millennial time scales. The background variations of ice rafting are punctuated by Heinrich layers| which appear to record the catastrophic collapse of the Laurentide ice sheet through the Hudson Strait. The objective of this paper is to document the evolution of glaciation on Laurentia during the last 43 C-14 kyr. We present a provenance study based on Ar-40/Ar-39 dates of individual hornblende grains from 57 samples taken at 2 ern spacing between 4 and 134 cm from core V23-14 (43.4degreesN| 45.25degreesW| 3177 m). Sedimentation rates outside of the Heinrich layers are very low in this core| but the Heinrich layers are easily identified. Laurentide glaciation did not extend into the ocean south of 55degreesN until about 26 C-14 kyr| and retreated to the coastline or beyond by 14 C-14 kyr. Documenting the history of this major ice sheet has significant implications for understanding ice rafting sources in more distal locations where mixing among different ice sheets is likely. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved. 6131,2003,2,3,Impacts of global warming on changes in the East Asian monsoon and the related river discharge in a global time-slice experiment,Changes in the East Asian monsoon and the related river discharge under global warming conditions are investigated using 2 time-slice simulations of the IS92a scenario with a T106 atmospheric general circulation model (ECHAM4) for 1971 to 1980 and 2041 to 2050. Daily runoff and drainage calculated by the land-surface scheme are used as input to a hydrological model to diagnose changes in the Yangtze River and Zhujiang River discharges. In the future climate| the simulated annual cycle of precipitation over the southeastern coastal area of China is systematically shifted about 1 mo ahead compared with the present-day climate| and the rainy season starts 1 mo earlier for the Yangtze River Valley and North China. In line with the surface-warming distribution change| the East Asian summer monsoon (EAM) flow strengthens. This causes increased precipitation in North China. In winter| the subtropical part of the EAM flow strengthens and leads to a large increase in rainfall over the EAM region. The discharges of the Zhujiang and Yangtze rivers in the future climate decrease in the late summer and autumn| to which both increased evaporation and an early retreat of the monsoon rainfall contribute. In the early and mid-summer| the Yangtze River discharge increases| mainly due to the large increase in precipitation in the preceding months| which has been stored in the catchment. 6064,2003,2,4,Impacts of warm winters and extreme rainstorms on the base consumption in a limed lake| southern Norway,The chemical composition of a limed take| the two main inlets and the outlet was monitored during a period of 3 years. The winters of 1991-1992 and 1992-1993 were unusually warm while the winter of 1993-1994 was more normal. The lake surface water was wind exposed in the warm winters and as a consequence of frequent turnovers the acid input from the catchment mixed with the whole lake water body. In the winter of 1993-1994| the lake was ice-covered for approximately 4 months. During this period the drainage water from the catchment flowed to the outlet of the lake in the upper 2-3 m of the water column and only some of the acid input was neutralised. This is compared to a complete neutralisation in the winter of 1992-1993. The in-lake loss of alkalinity during this warm winter was approximately 29 mueq/l (November-June) compared to approximately 7 mueq/l lakewater in 1993-1994. Acid drainage from the catchment induced by an extraordinary rainstorm with heavy sea-salt deposition contributed to the in-lake alkalinity consumption in spring 1993. As winter temperatures above 0degreesC and more frequent rainstorms may be common due to expected global warming| future increased lime consumption in-lakes may be projected in acidified areas as southern Norway. (C) 2003 Elsevier Science B.V. All rights reserved. 6049,2003,2,4,Implications of changes in freshwater flux from the Greenland ice sheet for the climate of the 21st century,[1] Two simulations of the 21st century climate have been carried out using| on the one hand| a coarse resolution climate general circulation model and| on the other hand| the same model coupled to a comprehensive model of the Greenland ice sheet. Both simulations display a gradual global warming up to 2080. In the experiment that includes an interactive ice sheet component| a strong and abrupt weakening of the North Atlantic thermohaline circulation occurs at the end of the 21st century. This feature is triggered by an enhanced freshwater input arising mainly from a partial melting of the Greenland ice sheet. As a consequence of the circulation decline| a marked cooling takes place over eastern Greenland and the northern North Atlantic. This result underlines the potential role of the Greenland ice sheet in the evolution of climate over the 21st century. 6234,2003,4,4,Importance of clouds to the decaying trend and decadal variability in the Arctic ice cover,The areal extent of the sea ice cover in the Arctic. Ocean has declined in. the last 40 years with increased decadal variability. The trend is clearly influenced by the radiation balance over. all seasons. A cloudiness increase in the fall| winter and spring contributes to a reduction in the absolute amount of net longwave radiation at the sea surface. In the summer| the reduced cloud cover has led to an increase in shortwave radiation| permitting more net outgoing radiation| and yielding a small increase in the total incoming radiation. All of these trends promote ice reduction| and may suggest the importance of clouds during a possible global warming in the near future. The effects of clouds and radiation are comparable with the albedo reduction associated with more open water| which absorbs more solar radiation in the summer. Analyses of the decadal variabilities reveal qualitatively the same effects as those of the|radiation on the ice cover. 6074,2003,3,3,Incineration: Efficient| economical| and environmental,Industries are continually looking for innovative ways to improve air quality and reduce greenhouse gas emissions. Incineration of waste gas products is not a new concept to the oil and gas industry| However in recent years| significant improvements in incinerator design and technology have resulted in optimal performance| increased reliability| and reduced capital and operating costs. Since the technology has a measurable 99.99% combustion efficiency with no visible flame| black smoke| or detectable odour| Petroleum companies are now considering incineration as a cost effective and environmentally responsible alternative to conventional flaring| Incineration is a proven method to reduce greenhouse gas emissions because the global warming potential (GWP) of methane|is 21 times greater than the GWP of CO2. Hence| the complete combustion process that incineration offers reduces the global warming effect and significantly improves air quality. Also assisting in reducing greenhouse gas emissions is the fact that incineration requires significantly less fuel gas to combust low heat content streams| such as acid or tail gas. 6144,2003,3,4,Including indirect environmental impacts in waste management planning,Activities within waste management systems| such as energy and material recovery| can lead to indirect environmental impacts that occur outside of waste management systems. In this paper| the effect of including indirect greenhouse-gas emissions on the choice of waste management solutions on a national level is explored. The global warming potentials (GWPs) of future waste management solutions for Sweden are compared. These include direct and indirect GWPs resulting from recovering power| heat| biogas| materials and nutrients. Furthermore| two of the assumptions that are presumed to be crucial for determining the indirect GWPs are examined in sensitivity analyses. It was found that indirect GWPs of waste management could be large when comparing a range of waste management solutions. Including indirect GWPs may even change the ranking of the solutions. However| the estimates of the indirect GWs are sensitive to the assumptions made. Including them involves large uncertainties. Despite this| some general conclusions regarding the preferability of the respective solutions can be drawn. Including indirect environmental impacts is important when providing information to support strategic planning that involves choosing among waste management solutions. Ultimately| it is a question of improving the ability of waste management planners to design environmentally sustainable and robust waste management systems. increased knowledge of the indirect environmental impacts of waste management can contribute to providing such an improvement. (C) 2002 Elsevier Science B.V. All rights reserved. 6118,2003,3,3,Increase of cleaning rate and reduction in global warming effect during C4F8O/O-2 remote plasma cleaning of silicon nitride by adding NO and N2O,During the chemical vapor deposition chamber cleaning and oxide etching processes using perfluorocompounds (PFCs)| recombined and non-reacted PFCs are emitted. The emission of PFCs needs to be controlled in the near future to reduce the effect on global warming. In this study| an optimum condition of C4F8O/O-2 cleaning chemistry for silicon nitride by using a remote inductively coupled plasma source was determined as a function of process parameters. Under the optimum condition| the net emission of PFCs during cleaning was quantified using a Fourier transform-infrared spectroscopy and then the effects of additive nitrogen-containing NO and N2O gases on the cleaning rate| the destruction removal efficiency and the million metric tons of carbon equivalent (MMTCE) were investigated. The addition of N2O and NO gases to C4F8O/O-2 cleaning chemistry dramatically increased the cleaning rate by the factor of congruent to9 and decreased the volume of emitted CF4 slightly. The increase in the cleaning rate and the decrease in the emitted volume of CF4 by the addition of N2O and NO contribute to the large decrease in the MMTCE values by 93 and 95%| respectively| compared to the case of cleaning without the additive gases. (C) 2003 Elsevier Science B.V. All rights reserved. 5999,2003,2,4,Increase of skull size in the red fox (Vulpes vulpes) and Eurasian badger (Meles meles) in Denmark during the twentieth century: an effect of improved diet?,The skulls of 272 red foxes (Vulpes vulpes) and 308 Eurasian badgers (Meles meles) collected in Denmark over the last 120 years were measured to determine any temporal changes in skull size (and. by implication| body size) during the studied period. We wished to determine whether global warming had resulted in a decrease in skull and body size in accordance with Bergmann's rule. Contrary to our predictions| there were no significant negative relationships between any of the four skull characters measured and mean annual temperature. Among badgers. two of the four characters measured had increased significantly during the twentieth century (zygomatic breadth by about 2% and length of upper molar by about 3.5%). but only in Jutland. In the red fox| three of the four skull characters measured had increased significantly during the twentieth century (zygomatic breadth by about 5%| length of fourth upper premolar|9 by about 7% and diameter of canine by about 9%). with one parameter (zygomatic breadth) increasing twice as fast in Zealand as in Jutland. All the above three characters are closely associated with diet: the size of the zygomatic arch is closely related to the size of the masseter muscle. the size of the carnassial and the diameter of canine are generally associated with prey size. and the size of the first molar is associated with grinding of grain and larger invertebrates. Larger teeth enable a predator to take and handle larger prey items. However| the fourth parameter (greatest length of skull) had not increased during the studied period. Since all the above skull characters are significantly related to body size| these results indicate that the body size of both species had increased during the twentieth century. The increase in skull characters is probably related to contemporaneous changes in Danish agriculture and land use| which| in turn resulted in changes to the foxes' and badgers' diets. 2807,2003,2,4,Increasing activity of coastal processes associated with climate change in Estonia,Estonia has a long (3|800 km) coastline due to numerous peninsulas| bays and islands (over 1|500). Owing to its flat and low-lying coastal zone| which is experiencing isostatic and tectonic uplift| the development of the coast should be stable| although activation of coastal processes| which are presumed to be associated with global climate change| has been observed in Estonia for the last 20-30 years. As there is little evidence of a sea level rise during this period| extensive erosion and alteration of depositional coasts| such as sandy beaches| appears to be largely due to the recent increased storminess in the easter Baltic Sea. Frequency of storm days varied greatly during the second half of the 20th century with a minimum in the 1960s and a maximum during the last two decades. The results of the Mann-Kendall test show a statistically significant an increasing trend in annual and winter storminess over the last half-century. This increase is probably associated with| increased westerlies and cyclonic activity in Northern Atlantic in winter resulting in warmer winters in| northern Europe and an ice-free Baltic Sea near the Estonian coast. This paper focuses on the relationships between storm frequency and wind speed and the shoreline dynamics of areas where coastal processes and shoreline development has been observed and recorded for the last 20-30 years. A dataset of storms was created and extremely stormy periods were identified in order to correlate storm data with the most significant recorded coastal change events. The most marked coastal changes in Estonia result from a combination of strong storms| high sea-levels induced by storm surge| ice free seas and unfrozen sediments| all of which enhance erosion and transport of sediments above the mean sea-level and inland the mean coastline. 6009,2003,2,4,Increasing Great Lake-effect snowfall during the twentieth century: A regional response to global warming?,The influence of the Laurentian Great Lakes on the climate of surrounding regions is significant| especially in leeward settings where lake-effect snowfall occurs. Heavy lake-effect snow represents a potential natural hazard and plays important roles in winter recreational activities| agriculture| and regional hydrology. Changes in lake-effect snowfall may represent a regional-scale manifestation of hemispheric-scale climate change| such as that associated with global warming. This study examines records of snowfall from several lake-effect and non-lake-effect sites throughout most of the twentieth century in order to 1) determine whether differences in snowfall trends exist between these settings and 2) offer possible linkages between lake-effect snow trends and records of air temperature| water temperature| and ice cover. A new| historic record of oxygen isotope [delta(18)O((CaCO3))] data from the sediments of three eastern Finger Lakes in central New York is presented as a means of independently assessing changes in Great Lakes lake-effect snowfall. Results reveal a statistically significant increasing trend in snowfall for the lake-effect sites| whereas no trend is observed in the non-lake-effect settings. The Finger Lake oxygen isotope record reflects this increase in lake-effect snow through a statistically significant trend toward lower delta(18)O((CaCO3)) values. Records of air temperature| water temperature| and lake ice suggest that the observed lake-effect snow increase during the twentieth century may be the result of warmer Great Lakes surface waters and decreased ice cover| both of which are consistent with the historic upward trend in Northern Hemispheric temperature due to global warming. Given projected increases in future global temperature| areas downwind of the Great Lakes may experience increased lake-effect snowfall for the foreseeable future. 6153,2003,2,3,Indian monsoon variability in a global warming scenario,The Intergovernmental Panel on Climate Change (IPCC) constituted by the World Meteorological Organisation provides expert guidance regarding scientific and technical aspects of the climate problem. Since 1990 IPCC has| at five-yearly intervals| assessed and reported on the current state of knowledge and understanding of the climate issue. These reports have projected the behaviour of the Asian monsoon in the warming world. While the IPCC Second Assessment Report (IPCC| 1996) on climate model projections of Asian/Indian monsoon stated "Most climate models produce more rainfall over South Asia in a warmer climate with increasing CO2"| the recent IPCC (2001) Third Assessment Report states "It is likely that the warming associated with increasing greenhouse gas concentrations will cause an increase in Asian summer monsoon variability and changes in monsoon strength." Climate model projections (IPCC| 2001) also suggest more El Nino-like events in the tropical Pacific| increase in surface temperatures and decrease in the northern hemisphere snow cover. The Indian Monsoon is an important component of the Asian monsoon and its links with the El Nino Southern Oscillation (ENSO) phenomenon| northern hemisphere surface temperature and Eurasian snow are well documented. In the light of the IPCC global warming projections on the Asian monsoon| the interannual and decadal variability in summer monsoon rainfall over India and its teleconnections have been examined by using observed data for the 131-year (1871-2001) period. While the interannual variations show year-to-year random fluctuations| the decadal variations reveal distinct alternate epochs of above and below normal rainfall. The epochs tend to last for about three decades. There is no clear evidence to suggest that the strength and variability of the Indian Monsoon Rainfall (IMR) nor the epochal changes are affected by the global warming. Though the 1990s have been the warmest decade of the millennium (IPCC| 2001)| the IMR variability has decreased drastically. Connections between the ENSO phenomenon| Northern Hemisphere surface temperature and the Eurasian snow with IMR reveal that the correlations are not only weak but have changed signs in the early 1990s suggesting that the IMR has delinked not only with the Pacific but with the Northern Hemisphere/Eurasian continent also. The fact that temperature/snow relationships with IMR are weak further suggests that global warming need not be a cause for the recent ENSO-Monsoon weakening. Observed snow depth over the Eurasian continent has been increasing| which could be a result of enhanced precipitation due to the global warming. 6035,2003,3,2,Industrial trial production of low energy belite cement,The Portland cement industry consumes large amounts of energy and produces huge quantities of carbon dioxide| which contribute to global warming| the so-called "Greenhouse Effect". Industrial trials are reported for the production of belite cements (approximate to3000 t) at lower temperatures and with lower lime saturation factors than for ordinary Portland cement. Belite cements with reasonably good properties have been made on an industrial scale from limestone| burnt clay| volcanic ash| pyrite ash and gypsum. A rapid rate of cooling improves the hydraulic activity| and also the physical-mechanical properties by stabilising reactive forms of belite. Such low energy cements provide a cheap alternative to Portland cement with properties that are acceptable for many applications and the additional benefit of possible improved durability. (C) 2002 Elsevier Ltd. All rights reserved. 5972,2003,2,4,Influence of the El Nino Southern Oscillation on fire regimes in the Florida everglades,Disturbances that are strongly linked to global climatic cycles may occur in a regular| predictable manner that affects composition and distribution of ecological communities. The El Nino Southern Oscillation (ENSO) influences worldwide precipitation patterns and has occur-red with regular periodicity over the last 130000 years. We hypothesized that ENSO| through effects on local weather conditions| has influenced frequency and extent of fires within Everglades National Park (Florida| USA). Using data from 1948 to 1999| we found that the La Nina phase of ENSO was associated with decreased dry-season rainfall| lowered surface water levels| increased lightning strikes| more fires| and larger areas burned. In contrast| the El Nino phase was associated with increased dry-season rainfall| raised surface water levels| decreased lightning strikes| fewer fires| and smaller areas burned. Shifts between ENSO phases every few years have likely influenced vegetation through periodic large-scale fires| resulting in a prevalence of fire-influenced communities in the Everglades landscape. 2734,2003,4,4,Integrated assessment modeling for global climate change: An infinite horizon optimization viewpoint,In this paper one uses an infinite time horizon optimal control paradigm to deal with three important issues in global climate change integrated assessment| namely the equitable treatment of all the generations involved| the representation of technical progress| and the uncertainty concerning technological progress and climate change processes. The notion of economic sustainability is associated with the concept of turnpike in infinite horizon optimization models. The issue of deciding on the proper discount rate is addressed in this context and a method is proposed to reconcile long term sustainability and short term time preference for current generations. One also formulates a model where environmental damage and/or technical progress are represented as stochastic jump processes. One calls this random evolution a mode switching process. In this context| sustainability is represented by a family of turnpikes| and the economy will be driven from one steady state to the other as the modes switch. These concepts are illustrated on the DICE model and their possible implementation in other types of integrated assessment models is discussed. 6129,2003,2,3,Integrated assessment of Hadley Centre (HadCM2) climate change projections on agricultural productivity and irrigation water supply in the conterminous United States - I. Climate change scenarios and impacts on irrigation water supply simulated with the HUMUS model,In response to a congressional mandate| the US Global Change Research Program organized a National Assessment of Climate Change focusing on geographic regions (e.g. Alaska| Great Plains) and sectors (e.g. public health| agriculture| water resources). This paper describes methodology and results of a study by researchers at the Pacific Northwest National Laboratory contributing to the water sector analysis. The subsequent paper makes use of the water supply results to estimate the climate change impacts on irrigated agriculture. The vulnerability of water resources in the conterminous US to climate changes in 10-year periods centered on 2030 and 2095 as. projected by the Hadley/United Kingdom Meteorological Office (UKMO) general circulation model (GCM; HadCM2) were modeled using the Hydrologic Unit Model for the United States (HUMUS). HUMUS| a biophysically based hydrology model| consists of a Geographical Information System (GIS) that provides data on soils| land use and climate to drive the Soil Water Assessment Tool (SWAT). The modeling was done at the scale of the eight-digit United States Geological Survey (USGS) Hydrologic Unit Area (HUA) of which there are 2101 in the conterminous US. Results are aggregated to the four- and two-digit (major water resource region| MWRR) scales for various purposes. Daily records of maximum/minimum temperature and precipitation (PPT) from 1961 to 1990 provided the baseline climate. Water yields (WY)| used as a measure of water supply for irrigation| increases from the 1961-1990 baseline period over most of the US in 2030 and 2095. In 2030| WY increases in the western US and decreases in the central and southeast regions. Notably| WY increases by 139 turn (35%) from baseline in the Pacific Northwest. Driven by higher temperatures and reduced precipitation| WY is projected to decrease in the Lower Mississippi and Texas Gulf basins. The HadCM2 (2095) scenario projects a climate significantly wetter than baseline| resulting in water yield increases of 38% on average. Water yield increases are projected to be significant throughout the eastern US-39% in the Ohio basin| for example. Water yields increase significantly in the western US| as well-57 and 76% in the Upper and Lower Colorado| respectively. Climate change also affects the seasonality of the hydrologic cycle. Early snowmelt is induced in western basins| leading to dramatically increased water yields in late winter and early spring. The simulations were run at current (365 ppm) and elevated (560 ppm) atmospheric CO2 concentrations [CO2] to account for the potential impacts of the 'CO2-fertilization' effect. The effects of climate change scenario were considerably greater than those due to elevated [CO2] but the latter| overalls decreased losses and augmented increases in water yield. (C) 2003 Elsevier Science B.V. All rights reserved. 6140,2003,3,2,Integration of fossil energy systems with CO2 sequestration through NH4HCO3 production,The increasing anthropogenic CO2 emission and global warming (thus climate change) have challenged the United States and other countries to find new and better ways to meet the world's increasing needs for energy while reducing greenhouse gases emissions. Here| we present a practical and revolutionary method that can sequester greenhouse gas emissions and| at the same time| benefit both agriculture and the economy. The proposed strategy utilizes an innovative application of chemical processes to convert CO2| NOx and SOx emissions into valuable fertilizers (mainly| NH4HCO3) that can enhance sequestration Of CO2 into soil and subsoil earth layers| reduce NO3- contamination of groundwater and stimulate photosynthetic fixation Of CO2 from the atmosphere. This invention integrates pollutant removing fertilizer production reactions with coal-fired power plants and other energy operations| resulting in a clean energy system that is in harmony with the earth ecosystem. This technology could contribute importantly to global CO2 sequestration and clean air protection. When this technology is in worldwide use| because of its high efficiency and carbon credit| in addition to the benefit of clean air protection and stimulation of photosynthetic fixation Of CO2 from the atmosphere| maximally 300 million tons Of CO2 per year (equivalent to about 5% of the CO2 emissions from coal-fired power plants in the world) from smokestacks can be placed into soil by the use of this technology. (C) 2002 Elsevier Science Ltd. All rights reserved. 6260,2003,3,4,Integration of life cycle assessment and population balance model for assessing environmental impacts of product population in a social scale - Case studies for the global warming potential of air conditioners in Japan,Scope. In this study| a dynamic model was built in which LCA and PBM were integrated to quantitatively assess the total environmental impacts induced by the product population in a society over time. Specifically| a determination was carried out concerning how Japan's air conditioner population is used (lifetime distribution| number of units| etc.) and an assessment was made concerning the Global Warming Potential (GWP) associated with the air conditioner population. Methods. The proposed dynamic model was applied to air conditioners for analyzing the total GWP caused by the air conditioner population in Japan from 1990 to 2010. To create a trend forecast model for future environmental load| scenarios for air conditioner production up to 2010 were formulated and the total GWP from the air conditioner population was predicted. Conducted also were sensitivity analyses whose parameters were air conditioner performance| lifetime and the rate of refrigerant recovery when retired units are processed. Results and Discussion. Applying the PBM to the air conditioner population in 2000| it was found that 81.5 million units consumed 5.94 x 10(10) kWh in that year| which was a 6.1% increase in the total annual power consumption in 1990. In both a stationary scenario and a steady growth (1.5% annual increase)| it was found that the total GWP would be 27.7% higher than in 1990 under the stationary scenario and 37.8% higher under the steady growth scenario. The improvements in air conditioner performance will have a small effect on reducing the total GWP from that population. Furthermore| in connection with the average lifetime| it was found that the GWP| due to refrigerant releases when units are disposed of| would be relatively large in 2000 and the following years. Conclusions. Thus| shorter product lifetimes will spur a replacement of air conditioners with new units| a situation that will only lead to the reduction of GWP if the recovery rate of refrigerant is to be achieved to more than 50% under the stationary scenario. Recommendations and Outlook. To meet COP3 targets for Japan in 2010 (i.e. to reach the same level as in 1990 for household appliances)| our study shows that it will be vital to raise the refrigerant recovery rate. If the number of air conditioners in use remains unchanged| recovery would have to be 45.7%| but under the steady growth scenario it would have to be at least 60.4%. Therefore| it will be difficult to meet COP3 targets unless the refrigerant recovery rate is strongly increased. This method is applicable to assess not only the GWP of air conditioners| but also other environmental impacts caused by a variety of product populations| which will be quite effective for setting targets of products' performance| policymaking| etc. 6147,2003,2,4,Inter-annual variability in the breeding performance of seabirds in relation to oceanographic anomalies that affect the Crozet and the Kerguelen sectors of the Southern Ocean,Global warming is expected to increase the frequency and intensity of inter-annual variation in Sea-Surface Temperatures (SST) associated with a latitudinal shift of frontal structures in the Southern Ocean. However| the long-term consequences of these major climatic events on the biotic environment remain poorly understood. We studied the effect of SST anomalies in the southern Indian Ocean on the breeding success of eight seabird species| and found these temperature anomalies to have different effects depending on the foraging habitat of the species. The breeding success of four seabird species foraging mainly south of the Polar Front in Antarctic waters was significantly depressed by warm SST occurring mainly in winter and spring| prior to breeding. Conversely| warm SST anomalies were associated with a higher breeding success for species foraging mainly north of the Polar Front| while no significant effect was found for two species that forage on the Kerguelen plateau. These different responses to changes in the SST were also observed for two closely related species (sooty albatross Phoebetria fusca and light-mantled sooty albatross. palpebrata) breeding at Kerguelen. These observations highlight the importance of multi-species long-term monitoring programs for understanding the ecological consequences of environmental variability. Our results suggest that the predicted southward shift of the Polar Front caused by oceanic warming could lead to an important decrease in the breeding performance of top predator seabirds depending on the location and changes of their foraging habitat in relation the Polar Front. 2784,2003,2,4,Interannual variation in terrestrial ecosystem carbon fluxes in China from 1981 to 1998,A dynamic biogeochemical model was used to estimate the responses of China's terrestrial net primary productivity (NPP)| soil heterotrophic respiration (HR) and net ecosystem productivity (NEP) to changes in climate and atmospheric CO2 from 1981 to 1998. Results show that China's total NPP varied between 2.89 and 3.37 Gt C/a and had an increasing trend by 0.32% per year| HR varied between 2.89 and 3.21 Gt C/a and grew by 0.40% per year| Annual NEP varied between -0.32 and 0.25 Gt C but had no statistically significant interannual trend. The positive mean NEP indicates that China's terrestrial ecosystems were taking up carbon with a total carbon sequestration of 1.22 Gt C during the analysis period. The terrestrial NEP in China related to climate and atmospheric CO2 increases accounted for about 10% of the world's total and was similar to the level of the United States in the same period. The mean annual NEP for the analysis period was near to zero for most of the regions in China| but significantly positive NEP occurred in Northeast China Plain| the southeastern Xizang (Tibet) and Huang-Huai-Hai Plain| and negative NEP occurred in the Da Hinggan Mountains| Xiao Hinggan Mountains| Loess Plateau and Yunnan-Guizhou Plateau. China's climate at the time was warm and dry relative to other periods| so the estimated NEP is probably lower than the average level. China's terrestrial NEP may increase if climate becomes wetter but is likely to continue to decrease if the present warming and drying trend sustains. 6242,2003,3,2,International greenhouse gas trading programs: a discussion of measurement and accounting issues,There is general scientific consensus that global warming is occurring and that this results from human activities| primarily burning fossil fuels. There is also a growing international consensus that the most cost-effective way to slow global warming is to establish international climate change trading programs that let institutions sell greenhouse gas (GHG) reductions in an international trading program. A well designed international GHG trading program could save billions or tens of billions of dollars and could result in a more rapid transfer of cleaner. more modern energy generating| transmitting and using technologies to developing nations| Establishing an international GHG trading program will require the development of international consensus rules on how to value and credit investments. for example in energy efficiency| that result in reduced emissions of greenhouse gases. Such a program would require the development of an international technical agreement on how to value emissions reductions attributed to energy-efficiency investments that reflect realistic estimates of future energy savings-and emissions reductions-that come from those investments. This paper examines five possible approaches for valuing energy savings which might serve as the basis for an international agreement. discusses the strengths and weaknesses of each approach. and discusses lessons learned from conducting this evaluation process. (C) 2002 Elsevier Science Ltd. All rights reserved. 6268,2003,5,4,Interplate dispersal paths for megathermal angiosperms,The dispersal of megathermal angiosperms between tectonic plates is reviewed on the basis of fossil evidence for the Cretaceous and Tertiary periods| since the radiation of the angiosperms| and the period of break-up of Gondwana. The combination of tectonic plate disassembly and redistribution| coupled with phases of global warming followed by pronounced cooling| has resulted in the formation of intermittent dispersal opportunities for frost-intolerant plants| and has been a major factor in determining the direction of angiosperm diversification. The Early Cretaceous radiation of angiosperms seems to show little relationship to the formation of Tethys. However| for the Late Cretaceous and Tertiary nine relevant dispersal routes can be differentiated that can be divided into two distinct categories: routes which formed following the break-up of Gondwana during the Late Cretaceous and Earlier Tertiary| when warm climates encouraged dispersal of megathermal elements globally| and routes which formed since the Middle Eocene| following phases of plate collision| as global climates were cooling down| inhibiting such dispersal. Most inter-plate dispersal of megathermal angiosperms took place in the Late Cretaceous and Early Tertiary at a time when global climates were markedly different from those of today| and the global area of megathermal vegetation several times greater than at present. Under such a scenario| it is likely than opportunities for speciation were much higher than for present-day megathermal plants. 2719,2003,2,4,Investigating SeaWinds terrestrial backscatter: Equatorial savannas of South America,Because tropical grasslands play an important role in the storage of global carbon| monitoring them is critical to evaluating global climate change. The goal of this research is to model seasonal SeaWinds Ku-band backscatter in five savanna areas of Colombia| Venezuela| and Brazil as a function of biophysical changes in the savanna landscape. Multiple regression modeling demonstrates that savanna Ku-band backscatter is a function of (1) savanna grass biomass/leaf area| (2) soil moisture| and (3) other soil characteristics. Fit for the regression models is excellent (R = 0.87 and 0.81| respectively for the horizontal and vertical polarization case). The horizontal-vertical polarization difference is also moderately related to precipitation (R = 0.71). The results from this modelin are consistent with theory predicated on previous C- and X-band research. The possibility of monitoring savanna vegetation| soil moisture| and rainfall using Ku-band radar and scatterometry is discussed. 6083,2003,3,4,Ion energy distribution and optical measurements in high-density| inductively coupled C4F6 discharges,Hexafluoro-1|3 butadiene (C4F6) is a potential etching gas with a very low global warming potential for the manufacturing of semiconductors| unlike commonly used fluorocarbon gases such as CF4 and c-C4F8. We report ion energy distributions| relative ion intensities and absolute total ion current densities measured at the edge of an inductively coupled gaseous electronics conference radio-frequency reference cell for discharges generated in pure C4F6 and C4F6:Ar mixtures. In addition| the ratio of radical densities relative to CF measured using submillimeter absorption spectroscopy and optical emission spectroscopy measurements are presented. These measurements of the C4F6 plasmas were made for several different gas pressures (0.67| 1.33| and 2.66 Pa) and gas mixture ratios (25%| 50%| 75%| and 100% C4F6 volume fractions). (C) 2003 American Institute Of Physics. 6180,2003,2,4,Is the ENSO phenomenon changing as a result of global warming?,It has been suggested by some that warm El Nino Southern Oscillation (ENSO) events have become stronger and more frequent as a result of global warming. This study aims to investigate whether there is any evidence for changes in the behavior of the ENSO phenomenon that may be attributed to global warming. Cluster analysis is carried out to group warm and cold events by various characteristics using the U.K. Climatic Research Unit air-temperature anomaly data set for the period 1856-1999. Analysis of the resulting groups of events and their relation to global temperature changes gives rise to various conclusions. First| the cold (La Nina) phase of the ENSO phenomenon has been more stable in the period of study than the warm (El Nino) one. Second| average strength warm events seem to be more frequent immediately preceding and during periods of steep global temperature rise| supporting the idea (Hunt| 1999) that more frequent El Ninos are a short-term response in ocean-atmosphere coupling to rising global temperature. 6276,2003,2,4,Koppen climate types in observed and simulated climates,The Koppen climate classification was applied to the observed gridded climatological sets and the outputs of four general circulation models (GCMs) over the continents of the Earth. All data had been acquired via the Data Distribution Centre established by the Intergovernmental Panel on Climate Change. The ability of the GCMs to simulate the Koppen climate zones identified in the real data was explored and possible future (global warming) changes in the climate types' distribution for each GCM were assessed. Differences in the area distributions derived from the GCMs' recent climate simulations give evidence about uncertainties generally involved in climate models. As to the global warming simulations| all GCM projections of warming climate (horizon 2050) show that the zones representing tropical rain climates and dry climates become larger| and the zones identified with boreal forest and snow climates together with the polar climates are smaller. 6039,2003,3,4,Land use-cover change processes in highly biodiverse areas: the case of Oaxaca| Mexico,Land use-cover changes (LUCC) such as deforestation| have resulted as global warming and a reduction of environmental services| with large negative consequences for mankind. Effects based on statistics alone have not been sufficient enough to detect| stop and eventually revert negative LUCC processes that are strongly related to biodiversity loss. It is| therefore| of prime concern to assess and depict cartographically| major LUCC processes simultaneously. Mexico harbors a large pool of biodiversity| mostly restricted to a few locations among which| The State of Oaxaca plays a major role. In this state| nevertheless| drastic negative LUCC processes are taking place. Land cover types| mapped in previous surveys| overlaid on recent Landsat imagery and 300 ground truth sites| were used to detect current LUCC. Rates of conversion of the most important LUCC processes were computed and mapped simultaneously. Oaxaca has lost over half a million hectares of forested areas during the last 20 years. The core results may contribute to the understanding of how LUCC and GIS methods can provide better and more targeted information that may help to improve conservation policies and land use planning strategies. (C) 2003 Elsevier Ltd. All rights reserved. 6115,2003,4,4,Large-scale temperature changes across the southern Andes: 20th-century variations in the context of the past 400 years,Long-term trends of temperature variations across the southern Andes (37 - 55degrees S) are examined using a combination of instrumental and tree-ring records. A critical appraisal of surface air temperature from station records is presented for southern South America during the 20th century. For the interval 1930 - 1990| three major patterns in temperature trends are identified. Stations along the Pacific coast between 37 and 43degreesS are characterized by negative trends in mean annual temperature with a marked cooling period from 1950 to the mid-1970s. A clear warming trend is observed in the southern stations (south of 46degreesS)| which intensifies at higher latitudes. No temperature trends are detected for the stations on the Atlantic coast north of 45degreesS. In contrast to higher latitudes in the Northern Hemisphere where annual changes in temperature are dominated by winter trends| both positive and negative trends in southern South America are due to mostly changes in summer ( December to February) temperatures. Changes in the Pacific Decadal Oscillation (PDO) around 1976 are felt in summer temperatures at most stations in the Pacific domain| starting a period with increased temperature across the southern Andes and at higher latitudes. Tree-ring records from upper-treeline were used to reconstruct past temperature fluctuations for the two dominant patterns over the southern Andes. These reconstructions extend back to 1640 and are based on composite tree-ring chronologies that were processed to retain as much low-frequency variance as possible. The resulting reconstructions for the northern and southern sectors of the southern Andes explain 55% and 45% of the temperature variance over the interval 1930 - 1989| respectively. Cross-spectral analysis of actual and reconstructed temperatures over the common interval 1930 - 1989| indicates that most of the explained variance is at periods >10 years in length. At periods >15 years| the squared coherency between actual and reconstructed temperatures ranges between 0.6 and 0.95 for both reconstructions. Consequently| these reconstructions are especially useful for studying multi-decennial temperature variations in the South American sector of the Southern Hemisphere over the past 360 years. As a result| it is possible to show that the temperatures during the 20th century have been anomalously warm across the southern Andes. The mean annual temperatures for the northern and southern sectors during the interval 1900 - 1990 are 0.53degreesC and 0.86degreesC above the 1640 - 1899 means| respectively. These findings placed the current warming in a longer historical perspective| and add new support for the existence of unprecedented 20th century warming over much of the globe. The rate of temperature increase from 1850 to 1920 was the highest over the past 360 years| a common feature observed in several proxy records from higher latitudes in the Northern Hemisphere. Local temperature regimes are affected by changes in planetary circulation| with in turn are linked to global sea surface temperature (SST) anomalies. Therefore| we explored how temperature variations in the southern Andes since 1856 are related to large-scale SSTs on the South Pacific and South Atlantic Oceans. Spatial correlation patterns between the reconstructions and SSTs show that temperature variations in the northern sector of the southern Andes are strongly connected with SST anomalies in the tropical and subtropical Pacific. This spatial correlation pattern resembles the spatial signature of the PDO mode of SST variability over the South Pacific and is connected with the Pacific-South American (PSA) atmospheric pattern in the Southern Hemisphere. In contrast| temperature variations in the southern sector of the southern Andes are significantly correlated with SST anomalies over most of the South Atlantic| and in less degree| over the subtropical Pacific. This spatial correlation field regressed against SST resembles the 'Global Warming' mode of SST variability| which in turn| is linked to the leading mode of circulation in the Southern Hemisphere. Certainly| part of the temperature signal present in the reconstructions can be expressed as a linear combination of four orthogonal modes of SST variability. Rotated empirical orthogonal function analysis| performed on SST across the South Pacific and South Atlantic Oceans| indicate that four discrete modes of SST variability explain a third| approximately| of total variance in temperature fluctuations across the southern Andes. 6016,2003,5,4,Late Maastrichtian paleoclimatic and paleoceanographic changes inferred from Sr/Ca ratio and stable isotopes,Milankovitch-scale cycles can be recognized in high-resolution delta(13)C| delta(18)O| Sr/Ca| mineralogical| and magnetic susceptibility data in hemipelagic sediments that span the last 700 kyr of the Maastrichtian at Elles| Tunisia. Oxygen isotope data reveal three cool periods between 65.50 and 65.55 Ma (21.5-23.5 m)| 65.26 and 65.33 Ma (8-11 in)| and 65.04 and 65.12 Ma (1.5-4 m)| and three warm periods between 65.33 and 65.38 Ma (12-16 m)| 65.12 and 65.26 Ma (4-8 in)| and 65.00 and 65.04 Ma (0-1.5 m). The cool periods are characterized by small surface-to-deep temperature gradients that reflect intensive mixing of the water column. The surface-to-deep Sr/Ca gradient generally correlates with the oscillating AT trend (temperature difference between surface and bottom waters). The carbon isotope composition of planktonic foraminifera indicates a continuous decrease in surface bioproductivity during Late Maastrichtian. Decreasing Delta(13)C values (difference between the delta(13)C values of surface and bottom dwelling foraminifera) and the carbon isotope ratios of the planktonic species at the onset of gradual warming at 65.50 Ma reflect a reduction in surface productivity as a result of decreased upwelling that accompanied global warming and possibly increased atmospheric pCO(2)| related to Deccan Trap volcanism. Time series analysis applied to magnetic susceptibility| delta(18)O| and Sr/Ca data identifies the 20 kyr precession| 40 kyr obliquity| and 100 kyr eccentricity Milankovich cycles. (C) 2003 Elsevier B.V. All rights reserved. 6028,2003,5,4,Late Quaternary seasonal sea-ice history of the northeastern Japan Sea,The Late Quaternary sea-ice history of the northeastern Japan Sea is discussed on the basis of the occurrence of dropstones and ice-rafted debris (IRD) in fine sediment cores. IRD was found in all strata except those from the Holocene and oxygen isotope stage 5.5. The largest expansion of sea ice was recognized at the last glacial maximum (LGM; oxygen isotope stage 2)| when the southern margin of seasonal sea ice was probably located in the vicinity of the Matsumae Plateau. The margin might occasionally have expanded further southward to off the Oga Peninsula. Sea ice expanded southward from mid-stage 5 to the LGM in response to global cooling| but with much fluctuation. Sea ice remained during deglaciation until around 10 ka| but after 10 ka it retreated northward rapidly in response to global warming and changes in surface water conditions. Greater fluctuations in IRD were found in core GH95-1208 collected from off Rumoi| Hokkaido| Japan. More IRD was found in sediments from late stage 3| late stage 5| and early stage 6. The fluctuations were not concordant with global climate changes (based on the standard oxygen isotope curve)| and may have been controlled by regional climate factors such as the strength of the winter monsoon| which is related in turn to high-latitude atmospheric circulation. 6230,2003,4,4,Late-flowering plants from northern Nova Scotia| Canada,Over 90 species of herbaceous dicotyledonous plants| representing 62 genera and 19 families| were recorded in blossom from northern Nova Scotia| Canada| during November and December 2001. Most observations were made during 10-20 November| but 29 species were in flower after 10 December. The number of species flowering declined steadily with time| rather than declining precipitously after the first frost. Only 6 of these 92 species are specifically reported in the floras of Nova Scotia as flowering in November. Examination of plant collections in the primary Nova Scotia herbaria showed that our collections represent the latest flowering records for all but one of these species in Nova Scotia. Accordingly| our collection extends the known flowering times for these species by an average of 45 days. For most species the late flowering is interpreted as an extension of normal phenology in response to unusually warm autumn weather| but for some species (e.g.| Viola cucullata| Ranunculus acris| Fragaria virginiana) it appears to represent a second flowering period. Our collections establish a base line of late flowering times that could be used as an indicator of regional climate change.
6110,2003,2,4,Leishmaniasis in Germany,In 2000| a reference center was created to systematically record leishmaniases in Germany. We analyzed 58 cases of leishmaniases imported during a 2-year period. These findings will serve as a baseline for the sandfly vector's anticipated northward move because of global warming and as an advisory for immunocompromised persons traveling to leishmaniasis-endemic areas. 6285,2003,3,4,Life cycle assessment (LCA) of cleaning-in-place processes in dairies,Four Cleaning-In-Place (CIP) methods for dairies were compared using life cycle assessment (LCA). The methods were conventional alkaline| acid cleaning with hot ater disinfection| one-phase alkaline cleaning with acid chemical disinfection| enzyme-based cleaning with acid chemical disinfection and the conventional method with disinfection by cold nitric acid at pH 2. Production of detergents| transport| the user phase in the dairy and waste management of containers were included. The user phase was found to be the most important part of the life cycle. The CIP methods with small volumes and low temperatures. Such as enzyme-based cleaning and one-phase alkaline cleaning. turned Out to be the best alternatives for the impact categories energy use. global warming| acidification| eutrophication and photo-oxidant Formation. Milk residues flushed out in the rinsing phase ere the main contributor to eutrophication| but the phosphorus and nitrogen in the detergents also influenced the results. Evaluation of toxic substances poses a methodological problem in LCA. In this study. detergents partly composed of toxic substances ere included. and the overall assessment vas that the one-phase alkaline cleaning method was preferable from an environmental point of A qualitative assessment of toxicity was performed. (C) 2003 Published by Elsevier Science Ltd. on behalf of Swiss Society of Food Science and Technology. 6297,2003,3,3,Life cycle assessment and long term CO2 reduction estimation of ultra lightweight vehicles using CFRP,Japanese annual oil consumption is about 300 GL (giga liter) and energy related CO2 emission is about 300 MtC (mega ton carbon). Among them| transport vehicles consume one third of the oil| 100 GL/year| and emit 20 percent of the CO2| 61 MtC/year. Then| the substitution of carbon fiber reinforced plastics (CFRP) for the structural material of transport vehicle is quite effective in lightening| fuel efficiency and hence the mitigation of global warming. In this paper| life cycle CO2 emission and energy consumption of the ultra lightweight automobile using CFRP are presented first. Then| the effect of lightweight and fuel cell automobiles on the mitigation of global oil consumption and CO2 emission is estimated under the assumption of Asian motorization. 6294,2003,3,3,Life cycle assessment of a willow bioenergy cropping system,The environmental performance of willow biomass crop production systems in New York (NY) is analyzed using life cycle assessment (LCA) methodology. The base-case| which represents current practices in NY| produces 55 units of biomass energy per unit of fossil energy consumed over the biomass crop's 23-year lifetime. Inorganic nitrogen fertilizer inputs have a strong influence on overall system performance| accounting for 37% of the non-renewable fossil energy input into the system. Net energy ratio varies from 58 to below 40 as a function of fertilizer application rate| but application rate also has implications on the system nutrient balance. Substituting inorganic N fertilizer with sewage sludge biosolids increases the net energy ratio of the willow biomass crop production system by more than 40%. While CO2 emitted in combusting dedicated biomass is balanced by CO2 adsorbed in the growing biomass| production processes contribute to the system's net global warming potential. Taking into account direct and indirect fuel use| N2O emissions from applied fertilizer and leaf litter| and carbon sequestration in below ground biomass and soil carbon| the net greenhouse gas emissions total 0.68 g CO2 eq. MJ(biomass produced)(-1). Site specific parameters such as soil carbon sequestration could easily offset these emissions resulting in a net reduction of greenhouse gases. Assuming reasonable biomass transportation distance and energy conversion efficiencies| this study implies that generating electricity from willow biomass crops could produce 11 units of electricity per unit of fossil energy consumed. Results from the LCA support the assertion that willow biomass crops are sustainable from an energy balance perspective and contribute additional environmental benefits. (C) 2003 Elsevier Science Ltd. All rights reserved. 6264,2003,3,3,Life cycle assessment of frozen cod fillets including fishery-specific environmental impacts,Goal| Scope and Background. The purpose of the present study was to perform an environmental assessment for the entire life cycle of a seafood product and to include fishery-specific types of environmental impact in inventory and assessment. Environmental data for a frozen block of cod fillets was collected and used for a Life Cycle Assessment| including the fishery-specific environmental aspects seafloor use and biological extraction of target| by-catch and discard species. The fishery takes place in the Baltic Sea where cod is mainly fished by benthic trawls and gillnets. Methods. The functional unit was a consumer package of frozen cod fillets (400 g) reaching the household. Data was gathered from fishermen| fishery statistics| databases| companies and literature. Fishery-specific issues like the impact on stocks of the target and by-catch species| seafloor impact and discarding were quantified in relation to the functional unit and qualitative impact assessment of these aspects was included. Results. Findings include the fact that all environmental impact categories assessed (Global Warming Potential| Eutrophication Potential| Acidification Potential| Photochemical Ozone Creation Potential and Aquatic Ecotoxiciy) are dominated by the fishery. Around 700 m(2) of seafloor are swept by trawls and around 50 g of under-sized cod and other marine species are discarded per functional unit. The phases contributing most to total environmental impact following fishery were transports and preparation in the household. The process industry and municipal sewage treatment cause considerable amounts of eutrophying emissions. Conclusions. Conclusions are that there are considerable options for improvement of the environmental performance of the seafood production chain. In the fishery| the most important environmental measure is to fish sustainably managed stocks. Speed optimisation| increased use of less energy-intensive fishing gear and improved engine and fuel technology are technical measures that would considerably decrease resource use and environmental impact caused by fishery. Due to the importance of fishery for the overall results| the most important environmental improvement option after landing is to maintain high quality and minimise product losses. Recommendations and Outlook. The need for good baseline data concerning resource use and marine environmental impact of fisheries in order to perform environmental assessment of seafood products was demonstrated. LCA was shown to be a valuable tool for such assessments| which in the future could be used to improve the environmental performance of the seafood production chain or in the development of criteria of eco-labelling of seafood products originating in capture fisheries. 6003,2003,3,4,Life cycle energy and environmental performance of a new university building: modeling challenges and design implications,A comprehensive case study life cycle assessment (LCA) was conducted of a 7300 m(2)| six-story building with a projected 75 year life span| located on the University of Michigan campus. The bottom three floors and basement are used as classrooms and open-plan offices; the top three floors are used as hotel rooms. An inventory of all installed materials and material replacements was conducted covering the building structure| envelope| interior structure and finishes| as well as the utility and sanitary systems. Computer modeling was used to determine primary energy consumption for heating| cooling| ventilation| lighting| hot water and sanitary water consumption. Demolition and other end-of-life burdens were also inventoried. The primary energy intensity over the building's life cycle is estimated to be 2.3 x 10(6) GJ| or 316 GJ/m(2). Production of building materials| their transportation to the site as well as the construction of the building accounts for 2.2% of life cycle primary energy consumption. HVAC and electricity account for 94.4% of life cycle primary energy consumption. Water services account for 3.3% of life cycle primary energy consumption| with water heating being the major factor| due to the presence of hotel rooms in this building. Building demolition and transportation of waste| accounts for only 0.2% of life cycle primary energy consumption. All impact categories measured (global warming potential| ozone depletion potential| acidification potential| nutrification potential and solid waste generation) correlate closely with primary energy demand. The challenges in developing a life cycle model of a complex dynamic system with a long service life are explored and the implications for future designs are discussed. (C) 2003 Elsevier B.V. All rights reserved. 6075,2003,3,3,Life cycle inventory analysis of a sewage treatment system using statistics,Public sewage treatment plants in Japan consume 6.3 billion kWh of electricity and produce 350 million tons of sludge annually| with serious impacts on the local and global environment. In this study| a Life Cycle Inventory of a sewage treatment plant for domestic wastewater was done to assess the environmental effects using data from statistics and previous studies. The system boundaries include sewage pipe construction and operation| sewage treatment plant construction and operation| material production and sludge treatment. The functional unit is defined as the treatment system of wastewater produced by one person in one year. Energy consumption and global warming are studied as the environmental parameters. The following conclusions have been drawn from the results. 1) Energy consumption and emission of Greenhouse Gases (GHGs) increase exponentially as the population density decreases. 2) If the actual population is less than the planned population| the operation efficiency of the sewage treatment plant decreases. 3) The energy consumption per person per year is 1|026 MJ| and CO2 equivalent emission factor is 89 kg. 4) Energy consumption for sewage treatment plant operation accounts for 78% of the total energy consumption. Under the assumption that 20% of the total carbon in the sludge is converted to CH4| the CH4 emitted from sludge landfill and the N2O generated by sludge incineration contribute respectively 35% and 14% to global warming. These results also show that further development of sludge recycling technology is desirable to decrease GHGs. 6159,2003,3,4,Life cycle inventory analysis of CO(2) and SO(2) emission of imperial smelting process for Pb-Zn smelter,Based on the principle of life cycle assessment| CO(2) and SO(2) emission of Imperial-Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and substitution method| the environmental impacts of co-products were allocated among the main products of zinc| lead and sulfuric acid. The related impacts were assessed by use of Global Warming Potential (GWP) and Acidification Potential (ACP). The results show that the GWP index from 1998 to 2000 is 11. 53| 11. 65| 10. 93 tCO(2)-eq/tZn respectively| the ACP index decreases from 14. 88 kgSO(2)-eq/tZn in 1998 to 10. 99 kgSO(2)-eq/tZn in 2000. Power and electricity generation| followed by smelting and zinc distillation| are mainly responsible for GWP. Sintering individually affects ACP. Reduction in greenhouse gas emissions of the ISP may come from energy conservation measures rather than from technological developments. And recycling more secondary Pb and Zn materials effectively treated by ISP| and reducing the amount of primary metal are the main ways to Put SO(2) emission under control. 5991,2003,3,4,Load-following control for dispersed generators using a PI controller,Recently| there has been growing interest in utilizing dispersed generation systems| which are grouped into micro turbine systems| co-generation systems| and so on| as a substitute for fuel oil energy and a technology to prevent global warming. Since start-up time of dispersed generation systems is short| it is possible to operate systems to supply load power corresponding to a demand. Moreover| PPSs (Power Producers and Suppliers) can participate in a power retail sales company| since deregulation of electric utilities was instituted in March 2000. However| PPSs have to keep instantaneous generating power commissioning rule| to maintain supply-and-demand balance between customer and supplier. Therefore| in this paper| we examine instantaneous generating power commissioning for dispersed generators where start-up time is short and it is possible to operate systems to supply a power load corresponding to a demand. We adopt a PI controller as a controller. The system is composed of double control loop in inner loop and in outer loop. In inner loop electric power is controlled and in outer loop electric energy is controlled. The controller parameters are designed using the pole-placement technique. The effectiveness of the proposed control system is confirmed by simulations. (C) 2003 Wiley Periodicals| Inc. 6200,2003,2,4,Local population dynamics are important to the conservation of metapopulations in highly fragmented landscapes,1. Population viability analyses (PVA) are extremely useful tools for the management of endangered species at the landscape scale. Two main families of spatially explicit models are available to perform PVA: (i) presence-absence models| in which local populations are either existing or extinct at each generation| and (ii) structured population models| in which the dynamics of each local population are modelled. In this study we compared the usefulness of both approaches for the prediction of the persistence of a species living in a highly fragmented landscape. 2. The cranberry fritillary Boloria aquilonaris is an arctic-alpine relict species in western Europe. It lives in landscapes where altitude or the proximity of oceans provide the high humidity conditions required for the formation of peat bogs| the only habitat of the butterfly. In such landscapes| the distribution of the butterfly is fragmented| following the natural distribution of peat bogs; this fragmentation is increased by human-induced peat bog destruction. 3. The study of the dynamics of a highly fragmented metapopulation of the cranberry fritillary in a network of 14 habitat patches totalling 26.23 ha revealed that: (i) the density at the equilibrium was c. 700 butterflies ha(-1) ; (ii) local population dynamics in small populations were negative; and (iii) six estimates of the growth rate R (t) showed large variations even in a large population. Both local extinctions and recolonization events are likely to occur| and two sites (one of 7 ha) unoccupied during two generations were recolonized in the third year. 4. We conclude that the future of this metapopulation is not guaranteed| given its large spatial scale and unbalanced| erratic local population dynamics. We hypothesize that global warming could explain the instability of local population dynamics detected here in addition to the decline of this arctic-alpine relict species| which is currently reported in all its refuge localities in the Netherlands. 5. Presence-absence models based on metapopulation structure and habitat characteristics should provide relatively safe predictions| as the population network (14 patches) is just below the minimum amount of suitable habitat (MASH) for the long-term persistence of a viable metapopulation. However| careful investigation of local population dynamics showed a high instability in the network| which is confirmed by population extinction at a large site. 6. Synthesis and applications. We urge conservation biologists to consider the local population dynamics of endangered species for the management of metapopulations in fragmented landscapes. In the case of the cranberry fritillary| continuing site protection is essential. 6273,2003,2,4,Long term study of the reaction of the edible dormouse Glis glis (Rodentia : Gliridae) to climatic changes and its interactions with hole-breeding passerines,This study is based on data collected in the course of a long-term study focusing on hole-breeding passerines in Frankfurt city and a low mountain range 70 km north-east of Frankfurt| Germany. Regular nest box checks have been carried out throughout the whole year in different sample areas| consisting of 2000 nestboxes| since 1969. Besides the collection of data on birds like the Great Tit (Parus major)| bats and insects the occurrence of Common Dormouse (Muscardinus avellanarius) and Edible Dormouse (Glis glis) was registered. To investigate whether interspecific competetion occurs| data from 6 sample areas with a total of 1190 nestboxes have been analyzed. The data show that mean population densities of G. glis during the birds' breeding season have increased. While most species of hole-breeding passerines start their breeding period on average one week earlier due to higher temperatures in spring| G. glis appears on average four weeks earlier in the nest boxes. This leads to an increase in predation of eggs or juvenile birds. The Pied Flycatcher (Ficedula hypoleuca)| a migratory bird and a late breeder| is especially affected. 6101,2003,2,3,Long time memory in global warming simulations,[1] Global power law scaling of near surface temperature spectra is determined in two scenario simulations and in NCEP re-analyses. The simulations use the coupled atmosphere-ocean models HadCM3 and ECHAM4/OPYC with greenhouse gas increase according to scenario IS92a in 1860-2099. Observations show a low-frequency power spectrum S(f) similar to 1/f over the oceans| a white spectrum in the inner continents| and S(f) similar to f(-0.3) in the coastal areas. The global distribution of the power law exponents is reproduced in the two simulations even in the 21st century with a pronounced temperature increase. 5963,2003,2,3,Long-term changes in dissolved oxygen concentrations in the ocean caused by protracted global warming,In the Earth's geological record massive marine ecological change has been attributed to the occurrence of widespread anoxia in the ocean [Jahren| 2002; White| 2002; Wignall and Twitchett| 1996]. Climate change projection till the end of this century predict a 4 to 7% decline in the dissolve oxygen in the ocean [Bopp et al.| 2002; Matear et al.| 2000; Plattner et al.| 2001; Sarmiento et al.| 1998] suggesting the potential for global warming to eventually drive the deep ocean anoxic. To examine the multicentury impact of protracted global warming on oceanic concentrations of dissolved oxygen| we use a climate system model and a low-order oceanic biogeochemical model. The models are integrated for an atmospheric equivalent CO2 concentration| which is specified to triple according to a standard scenario from the late nineteenth to the late twenty-first century| and then is subsequently held constant at that elevated level for an additional 6 centuries. For the present day| the model successfully reproduced the large-scale features of the dissolved oxygen field in the ocean. In the global warming simulation| the physical model displays marked changes in high-latitude oceanic stratification and overturning| including near-cessation of deep water renewal for depths greater than about 1.5 km during the period of elevated stable CO2 concentration. Our model predicts a decline in oxygen concentration through most of the subsurface ocean. Concentration changes in the thermocline waters result mainly from solubility changes in the upstream source waters| while changes in the deep waters result mainly from lack of ventilation and ongoing consumption of oxygen by remineralization of sinking particulate organic matter. Changes in the upper 2 km of the ocean generally show signs of equilibration by the end of the integration| but at greater depths| there occurs a slow but steady decline through to the end of the integration. By the end of the integration| we simulate a doubling of the volume of hypoxic water (less than 10 mumol/kg) in the thermocline of the eastern equatorial Pacific Ocean. During the integration deep ocean oxygen concentrations generally decline by between 20 and 40%| but| significantly| no extensive deep ocean anoxia develops during the period of integration| nor does it appear that it would likely do so for at least a further 4000 years of integration. Subsurface oxygen decline is moderated by an overall reduction in export production of particulate organic matter| which reduces oxygen consumption in the ocean interior due to the remineralization of this material. 6020,2003,2,3,Long-term climate variations in China and global warming signals,[1] In this work| the authors analyze the observed long-term variations of seasonal climate in China and then investigate the possible influence of increases in greenhouse gas concentrations on these variations by comparing the observations with the simulations of the second phase of the Coupled Model Intercomparison Project (CMIP2). The long-term variations of precipitation and temperature in China are highly seasonally dependent. The main characteristic of summer precipitation in China is a drying trend in the north and a wetting trend in the central part. The precipitation in winter shows an increasing trend in southern and eastern-central China. Interesting features have also been found in the transitional seasons. In spring| precipitation variations are almost opposite to those in summer. In autumn the precipitation decreases in almost the whole country except for the middle and lower reaches of the Yangtze River Valley. In addition| the seasonality of precipitation has become slightly weaker in recent decades in southern and eastern China. Pronounced warming is observed in the entire country in winter| spring| and autumn| particularly in the northern part of China. In summer a cooling trend in central China is particularly interesting| and cooling ( warming) trends generally coexist with wetting ( drying) trends. The correlativity between precipitation and temperature variations is weak in spring| autumn| and winter. It has also been found that the long-term climate variations in winter and summer in China may be connected to the warming trend in the sea surface temperature of the Indian Ocean. A comparison between the observed seasonal climate variations and the CMIP2 simulations of 16 models indicates that the observed long-term variations of winter| spring| and autumn temperature in China may be associated with increases in greenhouse gas concentrations. However| such a connection is not found for the summer temperature. The tremendous uncertainties among the models in precipitation simulations make it difficult to link the precipitation variations to global warming. 6201,2003,4,4,Long-term thermal evolution and effect of low power heating in an underground quarry,Vertical profiles of temperature have been monitored in the atmosphere of an underground quarry since June 2001. A long-term temperature increase of the order of 0.1 degreesC per year is observed. Three heating experiments with 100-W sources| performed to study plume dynamics| can also be used to investigate the effect of visits on this increase. Ten days after the 24-h heatings| the initial state is not restored. Artificial contributions to the observed long-term temperature trend| triggered by internal heat release| thus cannot be ruled out. This experiment defines strict criteria for the underground monitoring of global warming or the preservation of painted caves. (C) 2003 Academie des sciences. Published by Editions scientifiques et medicales Elsevier SAS. All rights reserved. 6014,2003,2,4,Long-term variations in the processes of polluting the Arctic atmosphere,Variations in the processes of atmospheric circulation in the Russian Arctic were studied during 20 years from 1981 through 2000. During this period| air exchange between northern Russia and Eurasia gradually decreased| and the probability of air mixing within the Arctic region increased. This resulted in a redistribution of the contributions of large industrial source regions to the content of anthropogenic microelements in the Arctic atmospheric aerosol. Moreover| during the processes of purifying the Arctic atmosphere| the importance of pollutant precipitation onto the underlying surface was increased| and the importance of pollutant removal by air masses outside the Arctic region was decreased. This resulted in variations in the mean atmospheric concentrations and fluxes of a number of heavy metals and other toxic microelements onto the underlying surface. In particular| during spring| the mean concentrations of anthropogenic constituents in the aerosol over the central region of the Russian Arctic decreased gradually only because of changes in the processes of atmospheric circulation. If a decrease of the intensity of anthropogenic emissions occurring in Europe and in the industrial regions of the former Soviet Union in the 1990s is taken into account| the annual average fluxes of anthropogenic pollutants onto the underlying surface of the Arctic had to a] so have been decreased at the end of the last century. On the whole| in the Northern Hemisphere| global warming must gradually decrease the efficiency of transport of anthropogenic pollutants by air masses from large industrial regions to the Arctic and| thus| decrease the importance of the atmosphere as a channel through which pollutants enter the Arctic region. 2816,2003,2,4,Lower survival probabilities for adult Florida manatees in years with intense coastal storms,The endangered Florida manatee (Trichechus manatus latirostris) inhabits the subtropical waters of the southeastern United States| where hurricanes are a regular occurrence. Using mark-resighting statistical models| we analyzed 19 years of photo-identification data and detected significant annual variation in adult survival for a subpopulation in northwest Florida where human impact is low. That variation coincided with years when intense hurricanes (Category 3 or greater on the Saffir-Simpson Hurricane Scale) and a major winter storm occurred in the northern Gulf of Mexico. Mean survival probability during years with no or low intensity storms was 0.972 (approximate 95% confidence interval = 0.9.61-0.980) but dropped to 0.936 (0.864-0.971) in 1985 with Hurricanes Elena| Kate| and Juan; to 0.909 (0.837-0.951) in 1993 with the March "Storm of the Century"; and to 0.817 (0.735-0.878) in 1995 with Hurricanes Opal| Erin| and Allison. These drops in survival probability were not catastrophic in magnitude and were detected because of the use of state-of-the-art statistical techniques and the quality of the data. Because individuals of this small population range extensively along the north Gulf coast of Florida| it was possible to resolve storm effects on a regional scale rather than the site-specific local scale common to studies of more sedentary species. This is the first empirical evidence in support 4 storm effects on manatee survival and suggests a cause-effect relationship. The decreases in survival could be due to direct mortality| indirect mortality| and/or emigration from the region as a consequence of storms.-Future impacts to the population by a single catastrophic hurricane| or series of smaller hurricanes| could increase the probability of extinction. With the advent in 1995 of a new 25- to 50-yr cycle of greater hurricane activity| and longer term change possible with global climate change| it becomes all the more important to reduce mortality and injury from boats and other human causes and control the loss of foraging habitat to coastal development. 2746,2003,2,4,Lutzomyia vectors for cutaneous leishmaniasis in Southern Brazil: ecological niche models| predicted geographic distributions| and climate change effects,Geographic and ecological distributions of three Lutzomyia sand flies that are cutaneous leishmaniasis vectors in South America were analysed using ecological niche modelling. This new tool provides a large-scale perspective on species' geographic distributions| ecological and historical factors determining them| and their potential for change with expected environmental changes. As a first step| the ability of this technique to predict geographic distributions of the three species was tested statistically using two subsampling techniques: a random-selection technique that simulates 50% data density| and a quadrant-based technique that challenges the method to predict into broad unsampled regions. Predictivity under both test schemes was highly statistically significant. Visualisation of ecological niches provided insights into the ecological basis for distributional differences among species. Projections of potential geographic distributions across scenarios of global climate change suggested that only Lutzomyia whitmani is likely to be experiencing dramatic improvements in conditions in south-eastern Brazil| where cutaneous leishmaniasis appears to be re-emerging; Lutzomyia intermedia and Lutzomyia migonei may be seeing more subtle improvements in climatic conditions| but the implications are not straightforward. More generally| this technique offers the possibility of new views into the distributional ecology of disease| vector| and reservoir species. (C) 2003 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved. 6079,2003,2,4,Malaria in Britain: Past| present| and future,There has been much recent speculation that global warming may allow the reestablishment of malaria transmission in previously endemic areas such as Europe and the United States. In this report we analyze temporal trends in malaria in Britain between 1840 and 1910| to assess the potential for reemergence of the disease. Our results demonstrate that at least 20% of the drop-off in malaria was due to increasing cattle population and decreasing acreages of marsh wetlands. Although both rainfall and average temperature were associated with year-to-year variability in death rates| there was no evidence for any association with the long-term malaria trend. Model simulations for future scenarios in Britain suggest that the change in temperature projected to occur by 2050 is likely to cause a proportional increase in local malaria transmission of 8-14%. The current risk is negligible| as >52|000 imported cases since 1953 have not led to any secondary cases. The projected increase in proportional risk is clearly insufficient to lead to the reestablishment of endemicity. 6171,2003,5,4,Mammalian response to global warming on varied temporal scales,Paleontological information was used to evaluate and compare how Rocky Mountain mammalian communities changed during past global warming events characterized by different durations (350| similar to10|000-20|000| and 4 million years) and different per-100-year warming rates (1.0degreesC| 0.1degreesC| 0.06-0.08degreesC| 0.0002-0.0003degreesC per 100 years). Our goals were to determine whether biotic changes observed today are characteristic of or accelerated relative to what took place during past global warming events and to clarify the possible trajectory of mammalian faunal change that climate change may initiate. This determination is complicated because actual warming rates scale inversely with the time during which temperature is measured| and species with different life-history strategies respond (or do not) in different ways. Nevertheless| examination of past global warming episodes suggested that approximately concurrent with warming| a predictable sequence of biotic events occurs at the regional scale of the central and northern United States Rocky Mountains. First| phenotypic and density changes in populations are detectable within 100 years. Extinction of some species| noticeable changes in taxonomic composition of communities| and possibly reduction in species richness follow as warming extends to a few thousand years. Faunal turnover nears 100% and species diversity may increase when warm temperatures last hundreds of thousands to millions of years| because speciation takes place and faunal changes initiated by a variety of shorter-term processes accumulate. Climate-induced faunal changes reported for the current global warming episode probably do not yet exceed the normal background rate| but continued warming during the next few decades| especially combined with the many other pressures of humans on natural ecosystems| has a high probability of producing effects that have not been experienced often| if ever| in mammalian history. 5994,2003,2,4,Management of water resources and low flow estimation for the Himalayan basins of Nepal,Reliable estimates of low flow are extremely important for the monsoonal mountainous areas of the Hindu Kush-Himalayan (HKH) region as people in this region are facing growing problems of water during dry periods in terms of both quality and quantity. Furthermore| increasing evidence of decrease in snow cover and retreat of glaciers due to global warming have been reported from various parts of the HKH| which has serious implications for low flow in the region. However| reliable methods for low flow are difficult to find and lack of hydrometeorological data have inhibited the development of such methods. This has posed serious problems for sustainable management of water resources systems in the region in view of the difficulties in low flow. This paper also discusses a method for low flow estimation in the mountainous regions of Nepal| which shares with other neighbouring areas the complexity in the nature of the terrain and climate| inadequate hydro-meteorological network and insufficient long-term reliable data on hydrometeorology. The method discussed is based on a method developed in the UK| for estimating the hydrological regime at ungauged sites. Regionalization of the flow has been developed applying multi-variate regression analysis of long-term hydro-meteorological data and catchment characteristics. A number of standardised flow duration type curves have been determined| and regression models of the flows and the topographical and geological characteristics of the catchments were established. The mean flow was estimated using the water balance principle where the long-term mean annual runoff is the difference between long-term average annual precipitation and long-term actual evapotranspiration. Regionalization has been carried out by developing grids of hydrological response. The grids allow the flow regime to be estimated at any point on any stream in the mountainous region of the country. This is the first regional method of this kind to be developed to estimate low flows from ungauged catchments in Nepal. Such a method is of great importance for Nepal as well as for the mountainous regions of other countries of the HKH region| as it allows assessment of water availability for the design of small hydropower| irrigation and water supply schemes| and contributes to the economic development and poverty alleviation. (C) 2003 Elsevier B.V. All rights reserved. 6279,2003,3,3,Material life cycle assessment for diecasting process,The main emphasis of this study is to evaluate the potential environmental impact of diecasting process| which is one of well organized and kind of green technologies in casting processes. Material life cycle assessment (MLCA) was carried out in actual diecasting factory that produces various lightweight aluminum and magnesium components to obtain life cycle inventory data| quantify environmental impacts and finally try to get solutions for environmental improvement. In diecasting process| most of environmental impacts come from melting of raw materials for abiotic resource depletion and global warming due to burning gas and electricity used. The problem of photochemical oxidant creation is induced by spraying and lubricating steps.
6166,2003,4,4,Measurements of the infrared absorption cross-sections of haloalkanes and their use in a simplified calculational approach for estimating direct global warming potentials,The infrared absorption cross-sections and integrated band intensities (IBIs) for 21 haloalkanes: CFCl3| CF2Cl2| CF2Br2| CH2F2| CHF2Cl| CHF2Br| CF3Br| CHCl2-CF2Cl| CHFCl-CFCl2| CHCl2-CF3| CHClBr-CF3| CHFCl-CF2Cl| CHFBr-CF3| CHF2-CF3| CH2Br-CF3| CH2F-CFCl2| CH2F-CF3| CH3-CCl3| CH3-CFCl2| CH3-CF2-CF3| and CHF2-CH2-CF3 were measured over the wavenumber range 400-1600 cm(-1) at T=295 K. The effect of air pressure on measured spectra was also investigated. These results are used to demonstrate a simple calculational approach for estimating the direct global warming potentials (GWPs) of such chemicals. The results obtained are compared with those derived from more comprehensive atmospheric modeling calculations appearing in the literature. (C) 2003 Elsevier Science B.V. All rights reserved. 6055,2003,2,4,Measures of economic impacts of weather extremes - Getting better but far from what is needed - A call for action,One of the primary driving forces behind weather research and development has been the losses caused by weather extremes. Unfortunately| available loss values have been more qualitative than quantitative. There has never been a concerted| organized effort to collect and quality control economic impact data for weather extremes. Numerous studies have been made| resulting in widely varying estimates of losses| and these have been limited by 1) an inability to access certain types of loss data; 2) a lack of attention to indirect| delayed impacts| including benefits; and 3) diverse and inconsistent sources of loss data. Numerous problems have resulted from the poor estimates of loss and lack of understanding of the data uncertainties. Federal relief payments for major events have escalated partly as a result of insufficient data to detect and understand society's changing vulnerability to extremes. Controversies over relief payments for major damaging events have occurred as a result of imprecise loss estimates. The insurance industry suffered major storm-related losses in the 1990s :because it lacked a database on weather-produced losses and was unable to anticipate time-shifting risks in setting rates. The absence of quality impact data has also led to questionable research priorities| and has generated incorrect perceptions in the public and media about the magnitude of impacts of events. The lack of precise loss values also limits adequate planning for future impacts| which is apt to lead to increased losses as society's vulnerability to extremes continues to increase. Recent pressures| including several major weather losses since 1988| and concern over the impacts of more extremes due to global warming| have led to better estimates of impacts. These pressures and government and insurance industry recognition of the need to better understand the ever-increasing costs have led to recent national assessments| calling for better impact data. The nation needs a continuing program to adequately measure losses from natural hazards and to maintain a quality database to guide government policies and private sector actions. 6047,2003,2,4,Mechanisms determining the variability of Arctic sea ice conditions and export,In an ocean - sea ice model of the Arctic and the northern North Atlantic driven with 50-yr NCEP - NCAR reanalysis data| no appreciable trend in sea ice volume is found for the period 1948 - 98. However| rather long subperiods| for example| 1965 - 95| exhibit a large decline in Arctic sea ice volume. These results and the current data situation make connecting "global warming'' to Arctic ice thinning very difficult because the large decadal and multidecadal variability masks any trend. Thermal and wind effects linearly contribute to the total sea ice volume variability. Wind stress forcing significantly contributes to the decadal variability in the Arctic ice volume| affecting both thermodynamic growth and the ice export rate. Ice export events are triggered by enhanced cyclonic wind stress over the eastern Arctic. However| large ice export events depend to a similar degree on the presence of thick ice that is generated in a preceding accumulation phase and do not depend on the local wind conditions around Fram Strait. 6293,2003,2,4,Meteorology and hydrology in yosemite national park: A sensor network application,Over half of California's water supply comes from high elevations in the snowmelt-dominated Sierra Nevada. Natural climate fluctuations| global warming| and the growing needs of water consumers demand intelligent management of this water resource. This requires a comprehensive monitoring system across and within the Sierra Nevada. Unfortunately| because of severe terrain and limited access| few measurements exist. Thus| meteorological and hydrologic processes are not well understood at high altitudes. However| new sensor and wireless communication technologies are beginning to provide sensor packages designed for low maintenance operation| low power consumption and unobtrusive footprints. A prototype network of meteorological and hydrological sensors has been deployed in Yosemite National Park| traversing elevation zones from 1|200 to 3|700 m. Communication techniques must be tailored to suit each location| resulting in a hybrid network of radio| cell-phone| land-line| and satellite transmissions. Results are showing how| in some years| snowmelt may occur quite uniformly over the Sierra| while in others it varies with elevation. 6223,2003,3,3,Methane emission reduction: An application of FUND,Methane is| after carbon dioxide| the most important anthropogenic greenhouse gas. Governments plan to abate methane emissions. A crude set of estimates of reduction costs is included in FUND| an integrated assessment model of climate change. In a cost-benefit analysis| methane emission reduction is found to be instrumental in controlling the optimal rate of climate change. In a cost-effectiveness analysis| methane emission reduction largely replaces carbon dioxide emission reduction. Methane emission reduction reinforces the case for international cooperation in climate policy| but complicates the efficient allocation of emission reduction efforts. Methane emission reduction at the short run does not help to achieve the ultimate objective of the Framework Convention on Climate Change. 6288,2003,3,4,Methane emissions of beef cattle on forages: Efficiency of grazing management systems,Fermentation in the rumen of cattle produces methane (CH4)Methane may play a role in global warming scenarios. The linking of grazing management strategies to more efficient beef production while reducing the CH4 emitted by beef cattle is important. The sulfur hexalluoride (SF6) tracer technique was used to determine the effects of best management practices (BMP) grazing compared with continuous grazing On CH4 production in several Louisiana forages during 1996-1998. Cows and heifers (Bos taurus) grazed common bermudagrass [Cynodon dactylon (L.) Pers.]| babiagrass (Paspalum notatum Flugge)| and ryegrass (Lolium multiflorum Lam.) pastures and were wintered on bahiagrass hay with supplements of protein molasses blocks (PMB)| cottonseed meal and corn (CSMC)| urea and corn (URC)| or limited ryegrass grazing (LRG). Daily CH4 emissions were between 89 and 180 g d(-1) for young growing heifers and 165 to 294 g d(-1) for mature Simbrah cows. Heifers on "ad lib" ryegrass in March and April produced only one-tenth the CH4 per kg of gain as heifers on LRG of 1 h. Using BMP significantly reduced the emission of CH4 per unit of animal weight gain. Management-intensive grazing (MIG) is a BMP that offers the potential for more efficient utilization of grazed forage crops via controlled rotational grazing and more efficient conversion of forage into meat and milk. Projected CH4 annual emissions in cows reflect a 22% reduction from BMP when compared with continuous grazing in this study. With the BMP application of MIG| less methane was produced per kilogram of beef gain. 6005,2003,2,2,Methane emissions of rice increased by elevated carbon dioxide and temperature,Methane (CH4) effluxes by paddy-culture rice (Oryza sativa L.) contribute about 16% of the total anthropogenic emissions. Since radiative forcing of CH4 at current atmospheric concentrations is 21 times greater on a per mole basis than that of carbon dioxide (CO2)| it is imperative that the impact of global change on rice CH4 emissions be evaluated. Rice (cv. IR72) was planted in sunlit| closed-circulation| controlled-environment chambers in which CH4 efflux densities were measured daily. The CO2 concentration was maintained at either 330 or 660 mumol mol(-1). Air temperatures were controlled to daily maxima and minima of 32123| 35/26| and 38/29degreesC at each CO2 treatment. Emissions of CH4 each day were determined during a 4-h period after venting and resealing the chambers at 0800 h. Diurnal CH4 effluxes on 77| 98| and 119 d after planting (DAP) were obtained similarly at 4-h intervals. Emissions over four-plant hills and over flooded bare soil were measured at 53|63| and 100 DAP. Emissions were negligible before 40 DAP. Thereafter| emissions were observed first in high-CO2| high-temperature treatments and reached a sustained maximum efflux density of about 7 mg m(-2) h(-1) (0.17 g m(-2) d(-1)) near the end of the growing season. Total seasonal CH4 emission was fourfold greater for high-CO2| high-temperature treatments than for the low-CO2| low-temperature treatment| probably due to more root sloughing or exudates| since about sixfold more acetate was found in the soil at 71 DAP. Both rising CO2 and increasing temperatures could lead to a positive feedback on global warming by increasing the emissions of CH4 from rice. 6215,2003,2,4,Methodological problems and amendments to demonstrate effects of temperature on the epidemiology of malaria. A new perspective on the highland epidemics in Madagascar| 1972-89,There is a growing consensus that changes in climate will have major consequences for human health through a reduction in the availability of food and an increasing frequency of natural disasters. However| the contribution of higher temperatures to vector-borne diseases| particularly malaria| remains controversial despite the known biological dependence of both vector and pathogen on climate. Misconceptions and inappropriate use of variables and methods have contributed to the controversy. At present there appears to be more support for non-climatic explanations to account for the resurgence of malaria in the African highlands| e.g. the deterioration of malaria control and the development of drug resistance. An attempt is made here to show that dismissing temperature as a driving force in the case of malaria is premature. Using a de-trended time-series of malaria incidence in Madagascar between 1972 and 1989 indicated that a minimum temperature during 2 months at the start of the transmission season can account for most of the variability between years (r(2) = 0.66). These months correspond with the months when the human-vector (Anopheles gambiae sensu lato) contact is greatest. The relationship between El Nino Southern Oscillation (ENSO) and temperature (r = 0.79)| and ENSO and malaria (r = 0.64)| suggests that there might be an increased epidemic risk during post-Nino years in the Madagascar highlands and therefore warrants increased vigilance and extended control efforts in the first half of 2003. This review suggests that the rejection of climate-disease associations in studies so far published may not have used biologically relevant climate parameters. It highlights the importance of identifying more relevant parameters during critical periods of the transmission season in order to aid epidemic forecasting and to assess the potential impact of global warming. 6314,2003,5,4,Mimomys in North America,The earliest record of the microtine rodent genus Mimomys is from West Siberia| where| over 5 million years ago| it evolved from Promimomys. From western Asia| early Mimomys dispersed both east and west (to North America and to Europe)| arriving at about the same time in both areas as a slightly larger and more evolved form that is essentially identical in both continents. Different species names are applied| as they obviously represent the beginnings of geographically separate lineages. The immigration of Mimomys to North America marks the beginning of the Blancan Mammal Age by original definition. The earliest dated North American record is the Upper Alturas Fauna of California| which is well dated by paleomagnetic stratigraphy| tephra "fingerprinting"| and potassium-argon dating at 4.8 Ma. Lindsay et al. (1999) have supported this age by paleornagnetic stratigraphy in two areas of Nevada. One other known fauna| the Maxum fauna of Contra Costa County| California| contains immigrant Mimomys that may be slightly older| but is not dated. Dispersal of the temperate-climate genus Mimomys between Eurasia and North America was through the Beringian Faunal Region| near the latitude of the Arctic Circle| and later intercontinental continuity of the genus was severely restricted by climate| not water. Other microtine rodents| more tolerant of cooler latitudes| were able to cross the Bering land area and thus integrate the biochronologies of the two continents| but the genus Mimomys is of little use in intercontinental correlation during most of the Pliocene. Eurasia and North America contain many faunal regions| and the temperate United States comprises at least two| separated by the Rocky Mountains. Each faunal region has| to an extent limited by its isolation| unique faunas and a different historic biochronology. Although the first Mimomys immigrants to North America and Europe were very similar| the genus evolved independently on the separate continents for the next 3.4 m.y.| producing species| subgenera| and ultimately| new genera dramatically different in the two areas. During this isolation| separate lineages in the United States resulted in the subgenus M. (Cosomys) and the genus Ophiomys in the Western Faunal Region and in the subgenus M. (Ogmodontomys) and the genus Hibbardomys in the Eastern Faunal Region. Although also climatically constrained| the barrier to dispersal between these two faunal regions of the United States was much less rigorous than in Beringia. Several times taxa dispersed along two documented routes between the Eastern and Western Faunal Regions of the United States: through Yellowstone Pass in western Wyoming and around the southern end of the Rocky Mountains through Arizona and New Mexico. These faunal interchanges are useful in correlating the two regional biochronologies| and times of exchange correlate with the climate changes that made the Rocky Mountains| or the region to the south of it| habitable by temperate Miniomys. About 1.3 Ma| global warming again permitted Mimomys to disperse through Beringia. At or slightly before this second immigration of Mimomys| the descendants of the first immigration had become extinct or had evolved into forms no longer conforming to the diagnosis of Mimomys. The new immigrants are assigned to the Eurasian subgenus Mimomys (Cromeromys) and they are known to have lived well into the Irvingtonian mammal age| less than 0.78 Ma. Present records thus indicate that the genus Mimomys and derived forms lived in the United States for over four million years before they became extinct. 5982,2003,3,4,Mitigation of nitrous oxide emissions in spray-irrigated grazed grassland by treating the soil with dicyandiamide| a nitrification inhibitor,Nitrous oxide (N2O) from animal excreta in grazed pasture systems makes up a significant component (c. 10%) of New Zealand's total greenhouse gas inventory. We report an effective method to decrease N2O emissions from animal urine patches by treating the soil with the nitrification inhibitor dicyandiamide (DCD)| in a simulated grazed dairy pasture system under spray irrigation. The soil was a free-draining Lismore stony silt loam (Udic Haplustept loamy skeletal) and the pasture was a mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). By treating the soil with DCD| N2O emissions were decreased by 76% following urine application in the autumn| from 26.7 kg N2O-N ha(-1) without DCD to an average of 6.4 kg N2O-N ha(-1) with DCD over the 6-month experimental period. N2O flux was decreased by 78% following urine application in the spring| from 18 kg N2O-N ha(-1) without DCD to 3.9 kg N2O-N ha(-1) with the application of DCD over the 3-month period. A single application of DCD immediately after urine was sufficient to effectively mitigate N2O emissions from the urine. The results showed that repeated applications of DCD after urine application| or mixing DCD with urine| offered no advantage over a single application of DCD immediately after urine deposition. 2817,2003,5,4,Mixed carbonate-siliciclastic record on the North African margin (Malta) - coupling of weathering processes and mid Miocene climate,We investigated rock outcrops spanning the middle Miocene| global climate-cooling step on the Maltese Islands in order to reconstruct continental weathering rates and terrigenous fluxes| as well as to explore the coupling between these later| regional climate and carbonate accumulations. Sedimentation at this location was dominated during the Oligocene and early Miocene by a transitional platform to slope carbonates but progressively switched to a clay-rich carbonate slope system in the middle Miocene. Around 13 Ma| an abrupt change toward clay-dominated marls occurred| and marl deposition persisted until the Tortonian (ca. 12 Ma)| when a shallow-water carbonate ramp was reestablished. Clay mineralogy and bulk-rock oxygen isotope analyses suggest that the deposition of the Blue Clay formation was mainly caused by global climate change and related change in the rate of continental weathering. A significant negative correlation (112 0.65) exists between the carbonate content and the 8110 record. This| combined with the variation of mass accumulation rate of terrigenous material| suggests that shorter-term periods of globally cooler climate (Mi events) were associated with higher rates of accumulation in continental-derived material. Since during the Miocene Malta was attached to the North African Margin| we propose that the observed trends were due to a regional increase in rainfall during cooler periods| which consequently increased continental weathering and runoff. We further suggest that this pattern was linked to the perturbation of atmospheric fronts due to an increased thermal gradient during the Miocene. Thus| regional increase in rainfall might have been linked to the northward migration of the Intertropical Convergence Zone (ITCZ). 6092,2003,2,4,Model study of the thermal storage system by FEHM code,The use of low-temperature geothermal resources is important from the viewpoint of global warming. In order to evaluate various underground projects that use low-temperature geothermal resources| we have estimated the parameters of a typical underground system using the two-well model. By changing the parameters of the system| six different heat extraction scenarios have been studied. One of these six scenarios is recommended because of its small energy loss. (C) 2003 CNR. Published by Elsevier Ltd. All rights reserved. 6236,2003,2,3,Modeled climate-induced glacier change in Glacier National Park| 1850-2100,The glaciers in the Blackfoot-Jackson Glacier Basin of Glacier National Park| Montana| decreased in area from 21.6 square kilometers (km(2)) in 1850 to 7.4km(2) in 1979. Over this same period global temperatures increased by 0.45degreesC (+/- 0.15degreesC). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of glaciers and of the response of vegetation to climate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios| one based on carbon dioxide-induced global warming and the other on a linear temperature extrapolation. Under the former scenario| all glaciers in the basin will disappear by|the year 2030| despite predicted increases in precipitation; under the latter| melting is slower. Using a second model| we analyzed vegetation responses to variations in soil moisture and increasing temperature in a complex alpine landscape and predicted where plant communities are likely to be located as conditions change. 2714,2003,2,4,Modeling current and future potential wintering distributions of eastern North American monarch butterflies,Monarch butterflies overwinter in restricted areas in montane oyamel fir forests in central Mexico with specific microclimates that allow the butterflies to survive for up to 5 months. We use ecological niche modeling (ENM) to identify areas adequate for overwintering monarch colonies under both current and future climate scenarios. The ENM approach permits testing and validation of model predictivity| and yields quantitative| testable predictions regarding likely future climate change effects. Our models predicted monarch presence with a high degree of accuracy| and indicated that precipitation and diurnal temperature range were key environmental factors in making locations suitable for monarchs. When we projected monarch distribution onto future climate scenarios (Hadley Centre climate models)| we found that conditions were likely to be inadequate across the entire current winter range| particularly owing to increased cool-weather precipitation that could cause increased mortality. This study applies ENM to understanding the seasonal dynamics of a migratory species under climate change| and uses ENM to identify key limiting environmental parameters in species' responses to climate change. 5981,2003,2,4,Modeling shallow autocompaction in coastal marshes using cesium-137 fallout: Preliminary results from the Trinity River Estuary| Texas,Accurate prediction of changes in the relative elevation of coastal marsh surfaces has gained considerable importance in light of global-warming-induced sea-level rise. Shallow autocompaction is an important component of elevation change that acts to decrease relative elevation. Unlike vertical accretion| which can be determined from repeated surveys of artificial marker horizons| autocompaction is difficult to measure. This report presents the results of a preliminary study that uses cesium-137 dating and down-core measurements of sediment bulk density to numerically model vertical accretion| shallow autocompaction and surface elevation change. The models produce vertical accretion rates that are comparable to rates derived from artificial marker horizons| and long-term surface elevation changes that are in close agreement with sedimentation rates based on cesium-137 dating of well-compacted sediment. The model results suggest that average annual vertical accretion may be higher than average annual surface elevation change by a factor of 1.6 to 21. Sedimentation rates derived from cesium-137 dating also are higher than average annual surface elevation change by a factor of 1.1 to 4.7. These findings suggest that sedimentation rates based on cesium-137 dating will tend to be lower than vertical accretion and higher than long-term surface elevation change. The results of the study re-emphasize the importance of fully accounting for shallow autocompaction when attempting to predict marsh surface elevation change. 2720,2003,4,4,Modeling soil carbon from forest and pasture ecosystems of Amazon| Brazil,Conversion of tropical forest to agricultural management has important implications for C storage in soils and global climate change. The Nova Vida Ranch in the Western Brazilian Amazon basin provided a unique opportunity to study the conversion of tropical forests to pastures established in 1989| 1987| 1983| 1979| 1972| 1951| and 1911| in comparison with uncleared forest. Soils were analyzed for organic C| bulk density| total N| pH| clay content| and biomass C. The forest soil contained 34 Mg C ha(-1) in the 0- to 30-cm layer: modeling clearance and conversion to pasture caused an initial fall in the C stock| followed by a slow rise. After 88 yr| the pasture soil contained 53% more C than the forest soil. The increase in total N on conversion to pasture was less marked| which led to C/N ratios in the pasture soils being higher than in the forest soil. The Rothamsted C turnover model (RothC-26.3) was used to simulate changes in the 0- to 10- and 0- to 30-cm layer of soils when forest was converted to pasture. The model predicted that conversion to pasture would cause a 54% increase in the stock of organic C in the top 30 cm of soil in 100 yr. The modeled input of plant C to the 0- to 30-cm layer of soil under pasture was assumed to be 8.28 Mg C ha(-1) yr(-1). The model provided a reasonable estimate of the microbial biomass (BIO) C in the 0- to 10-cm soil layer. This was an independent test of model performance| because no adjustments were made to the model to generate output. 6206,2003,4,4,Modeling soil organic carbon change in croplands of China,Using 1990 conditions| we modeled carbon (C) and nitrogen (N) biogeochemical cycles in croplands of China (and| for comparison| the United States) to estimate the annual soil organic-carbon (SOC) balance for all cropland. Overall| we estimate that China's croplands lost 1|.6% of their SOC (to a depth of 0.3 in) in 1990| and that U.S. cropland lost 0.1%. A key element in this difference was that similar to25% of aboveground crop residue in China was returned to the soil| compared to similar to90% in the United States. In China| SOC losses were greatest in the northeast (similar to10(3) kg C.ha(-1).yr(-1))| and were generally smaller (<0.5 X 10(3) kg C.ha(-1).yr(-1)) in regions with a longer cultivation history. Some regions showed SOC gains| generally <10(3) kg C.ha(-1).yr(-1). Reduced organic-matter input to China's cropland soils| and lower overall SOC levels in those soils| led to lower levels of N mineralization in the simulations| consistent with higher rates of synthetic-fertilizer application in China. C and N cycles are closely linked to soil fertility| crop yield| and non-point-source environmental pollution. 6098,2003,2,4,Modelling leaf gas exchanges to predict functional trends in Mediterranean Quercus ilex forest under climatic changes in temperature,A simple model based on the "big leaf" assumption and calibrated with field eco-physiological measures of gas exchanges is used to simulate the effects of temperature increase on net primary production| total canopy transpiration and the dimensionless decoupling coefficient Omega of Holm oak forests. Two different annual average air temperatures: 14.6 and 18.0degreesC are considered| they are respectively the average current temperature and the one expected in the next 50 years in the Mediterranean area if the trend of global warming will continue. The model simulates the behaviour of the three parameters by assuming no changes in the effects of water constraints at both the temperatures. The model has been implemented by STELLA((R)) II software. According to the model| the increase of air temperature affects both the net primary productivity (6.3%) and the water losses by canopy transpiration (37.2%). The model predicts an average decoupling factor| Omega| of about 0.26 at both temperatures of 14.6 and 18.0degreesC. This value is in the range between Heathlands and Forest| suggesting that at the average annual temperature of 18.0degreesC the Holm oak forest will start to respond in a similar way to more xeric plant communities. (C) 2003 Elsevier B.V. All rights reserved. 6097,2003,2,2,Modelling the impacts of climate change and methane emission reductions on rice production: a review,Rice agriculture is not only affected by climate change| but also contributes to global warming through the release of methane into the atmosphere. In 1989| a major research project was initiated at the International Rice Research Institute in the Philippines to investigate relationships between climate change and rice production. A second project started in 1993 to investigate| in more detail| mitigation options that could be employed to help reduce CH(4) emissions from rice cultivation. An important component of all of this work was the quantification of these interactions between climate change and rice production into simulation models| and their subsequent use to upscale field measurements to national and regional levels. The first project developed such a model to integrate existing knowledge of effects of increased levels of CO(2) and temperature on rice growth| and used this to predict the impact of various climate change scenarios on rice production in SE Asia. In the second project| routines describing the dynamics of CH(4) production and emission from the soil were linked to a crop simulation model to estimate the effect of different crop management scenarios on national CH(4) emissions from various countries in the region. With the recent completion of the second project| it is timely to review this modelling work describing the relationships between the global environment and rice production| a task which we attempt in the present paper. The advantages and disadvantages of the modelling approaches used and other issues relating to the upscaling of field measurements to national and regional levels are discussed. Future research directions in this area are also identified. (C) 2003 Elsevier Science B.V. All rights reserved. 6270,2003,3,3,Models to predict emissions of health-damaging pollutants and global warming contributions of residential fuel/stove combinations in China,Residential energy use in developing countries has traditionally been associated with combustion devices of poor energy efficiency| which have been shown to produce substantial health-damaging pollution| contributing significantly to the global burden of disease| and greenhouse gas (GHG) emissions. Precision of these estimates in China has been hampered by limited data on stove use and fuel consumption in residences. In addition limited information is available on variability of emissions of pollutants from different stove/fuel combinations in typical use| as measurement of emission factors requires measurement of multiple chemical species in complex burn cycle tests. Such measurements are too costly and time consuming for application in conjunction with national surveys. Emissions of most of the major health-damaging pollutants (HDP) and many of the gases that contribute to GHG emissions from cooking stoves are the result of the significant portion of fuel carbon that is diverted to products of incomplete combustion (PIC) as a result of poor combustion efficiencies. The approximately linear increase in emissions of PIC with decreasing combustion efficiencies allows development of linear models to predict emissions of GHG and HDP intrinsically linked to CO2 and PIC production| and ultimately allows the prediction of global warming contributions from residential stove emissions. A comprehensive emissions database of three burn cycles of 23 typical fuel/stove combinations tested in a simulated village house in China has been used to develop models to predict emissions of HDP and global warming commitment (GWC) from cooking stoves in China| that rely on simple survey information on stove and fuel use that may be incorporated into national surveys. Stepwise regression models predicted 66% of the variance in global warming commitment (CO2| CO| CH4| NOx| TNMHC) per 1 MJ delivered energy due to emissions from these stoves if survey information on fuel type was available. Subsequently if stove type is known| stepwise regression models predicted 73% of the variance. Integrated assessment of policies to change stove or fuel type requires that implications for environmental impacts| energy efficiency| global warming and human exposures to HDP emissions can be evaluated. Frequently| this involves measurement of TSP or CO as the major HDPs. Incorporation of this information into models to predict GWC predicted 79% and 78% of the variance respectively. Clearly| however| the complexity of making multiple measurements in conjunction with a national survey would be both expensive and time consuming. Thus| models to predict HDP using simple survey information| and with measurement of either CO/CO2 or TSP/CO2 to predict emission factors for the other HDP have been derived. Stepwise regression models predicted 65% of the variance in emissions of total suspended particulate as grams of carbon (TSPC) per 1 MJ delivered if survey information on fuel and stove type was available and 74% if the CO/CO2 ratio was measured. Similarly stepwise regression models predicted 76% of the variance in COC emissions per MJ delivered with survey information on stove and fuel type and 85% if the TSPC/CO2 ratio was measured. Ultimately| with international agreements on emissions trading frameworks| similar models based on extensive databases of the fate of fuel carbon during combustion from representative household stoves would provide a mechanism for computing greenhouse credits in the residential sector as part of clean development mechanism frameworks and monitoring compliance to control regimes. (C) 2002 Elsevier Science Ltd. All rights reserved. 2705,2003,2,1,Modern global climate change,Modern climate change is dominated by human influences| which are now large enough to exceed the bounds of natural variability. The main source of global climate change is human-induced changes in atmospheric composition. These perturbations primarily result from emissions associated with energy use| but on local and regional scales| urbanization and land use changes are also important. Although there has been progress in monitoring and understanding climate change| there remain many scientific| technical| and institutional impediments to precisely planning for| adapting to| and mitigating the effects of climate change. There is still considerable uncertainty about the rates of change that can be expected| but it is clear that these changes will be increasingly manifested in important and tangible ways| such as changes in extremes of temperature and precipitation| decreases in seasonal and perennial snow and ice extent| and sea level rise. Anthropogenic climate change is now likely to continue for many centuries. We are venturing into the unknown with climate| and its associated impacts could be quite disruptive. 2758,2003,2,4,Modifiers of the temperature and mortality association in seven US cities,This paper examines effect modification of heat- and cold-related mortality in seven US cities in 1986-1993. City-specific Poisson regression analyses of daily noninjury mortality were fit with predictors of mean daily apparent temperature (a construct reflecting physiologic effects of temperature and humidity)| time| barometric pressure| day of the week| and particulate matter less than 10 mum in aerodynamic diameter. Percentage change in mortality was calculated at 29degreesC apparent temperature (lag 0) and at -5degreesC (mean of lags 1| 2| and 3) relative to 15degreesC. Separate models were fit to death counts stratified by age| race| gender| education| and place of death. Effect estimates were combined across cities| treating city as a random effect. Deaths among Blacks compared with Whites| deaths among the less educated| and deaths outside a hospital were more strongly associated with hot and cold temperatures| but gender made no difference. Stronger cold associations were found for those less than age 65 years| but heat effects did not vary by age. The strongest effect modifier was place of death for heat| with out-of-hospital effects more than five times greater than in-hospital deaths| supporting the biologic plausibility of the associations. Place of death| race| and educational attainment indicate vulnerability to temperature-related mortality| reflecting inequities in health impacts related to climate change. 6192,2003,2,4,Monsoon variability in the Himalayas under the condition of global warming,An ice core-drilling program was carried out at the accumulation area of Dasuopu glacier (28degrees23'N| 85degrees43'E| 7100 m a.s.l.) in the central Himalayas in 1997. The ice core was analyzed continuously for stable isotopes (delta(18)O)| and major ions throughout the core. Cycles indicated by delta(18)O| cations were identified and counted as seasonal fluctuations as annual increment from maximum to maximum values. Reconstructed 300-year annual net accumulation (water equivalent) from the core| with a good correlation to Indian monsoon| reflects a major precipitation trend in the central Himalayas. The accumulation trend| separated from the time series| shows a strong negative correlation to Northern Hemisphere temperature. Generally| as northern hemisphere temperature increases 0.1degreesC| the accumulation decreases about 80 nun| reflecting monsoon rainfall in the central Himalayas has decreased over the past decades in the condition of global warming. 5993,2003,2,4,Mountain and subpolar glaciers show an increase in sensitivity to climate warming and intensification of the water cycle,The time-series of all available records of seasonal and annual glacier mass balances| equilibrium line altitude| accumulation area ratio and change in surface area of about 300 glaciers have been compiled| digitized| quality checked and analyzed over the period of almost four decades (1961 - 1998). These time-series show significant changes towards loss in glacier area and volume in global scale with accelerated rate| especially since the end of 1980's. The remarkable feature in this change is the increase of both winter and summer balances| which implies that glaciers are intensifying the water cycle in time of global warming. The sensitivity of glacier mass balance in regard to temperature and precipitation has also increased which resulted in an increase of glacier contribution to sea level rise from 0.15 mm/yr in 1961 - 1976 (10% of total sea-level rise) to 0.41 mm/yr in 1988 - 1998 (27% of total sea-level rise). Glacier contribution to the ocean has the potential to grow due to increasing snow accumulation and involving into the water cycle larger areas of individual glaciers around the Antarctic ice sheet. (C) 2003 Elsevier B.V. All rights reserved. 2822,2003,4,4,Multi-resolution time series analysis applied to solar irradiance and climate reconstructions,A better understanding of natural climate variability is crucial for global climate change studies and the evaluation of the sensitivity of the climate system to imposed perturbations. External forcing factors might contribute substantially to both high and low frequency variations in climate but a clear separation of their impact from internally generated fluctuations is difficult. We employ wavelet decomposition to identify common characteristics in forcing and climatic time series of the last four centuries. Here| we focus on solar irradiance variations by applying this statistical method to a selection of widely used proxy-based reconstructions. Major variability components are isolated through time-scale decomposition. Two classical solar modes (85 and 11 years) are not only identified within the limited time period covered by the solar datasets| but their relative influences on climate as represented by hemispheric surface temperature reconstructions are also estimated. While the low-frequency component shows close ties between solar variations and surface climate| a relationship between the 11-year sunspot cycle and temperature reconstructions is more difficult to attribute. However| the statistical multi-resolution analysis appears to be an ideal tool to uncover relationships and their changes at different temporal scales normally hidden by the strong background noise in the climate system. (C) 2002 Elsevier Science Ltd. All rights reserved. 2780,2003,2,4,Multidecadal trends in North American Atlantic salmon (Salmo salar) stocks and climate trends relevant to juvenile survival,Landings of North American Atlantic salmon (Salmo salar) over the past century show multidecadal patterns| which most recently characterize unprecedented declines in abundance. Stock size is compared with sea surface temperature (SST) data in the marine nurseries of post-smolt Atlantic salmon. A previously described correlation between stock abundance and winter SST conditions was again documented; however| of more relevance to the survival of salmon post-smolts| a correlation was also observed between abundance and spring SST in the Gulf of St. Lawrence. The relevance of the winter SST correlation was further investigated by considering winter conditions in the freshwater nurseries as a factor causing elevated overwintering mortality of pre-migrant parr. The salmon abundance time series was compared with air temperature and rainfall trends averaged over time and space. Air temperature and rainfall do not appear to be significant environmental variables in shaping salmon recruitment. The timing of smolt runs appears to be out of synchronization with ocean conditions in the post-smolt nursery areas. The relationship between marine and freshwater impacts may change with changing climate conditions. Persistent positive phase forcing in the North Atlantic Oscillation raises the concern that recent declines in Atlantic salmon are| in part| due to global climate change. 2811,2003,4,4,New distributional modelling approaches for gap analysis,Synthetic products based on biodiversity information such as gap analysis depend critically on accurate models of species' geographic distributions that simultaneously minimize error in both overprediction and omission. We compared current gap methodologies| as exemplified by the distributional models used in the Maine Gap Analysis project| with an alternative approach| the geographic projections of ecological niche models developed using the Genetic Algorithm for Rule-Set Prediction (GARP). Point-occurrence data were used to develop GARP models based on the same environmental data layers as were used in the gap project| and independent occurrence data used to test both methods. Gap models performed better in avoiding omission error| but GARP better avoided errors of overprediction. Advantages of the point-based approach| and strategies for its incorporation into current gap efforts are discussed. 6238,2003,4,4,New evidence for effects of land cover in China on summer climate,The effects of land cover in different regions of China on summer climate are studied by lagged correlation analysis using NOAA/AVHRR normalized difference vegetation index (NDVI) data for the period of 1981-1994 and temperature| precipitation data of 160 meteorological stations in China. The results show that the correlation coefficients between NDVI in previous season and summer precipitation are positive in most regions of China| and the lagged correlations show a significant difference between regions. The stronger correlations between NDVI in previous winter and precipitation in summer occur in Central China and the Tibetan Plateau| and the correlations between spring NDVI and summer precipitation in the eastern arid/semi-arid region and the Tibetan Plateau are more significant. Vegetation changes have more sensitive feedback effects on climate in the three regions (eastern arid/semi-arid region| Central China and Tibetan Plateau). The lagged correlations between NDVI and precipitation suggest that| on interannual time scales| land cover affects summer precipitation to a certain extent. The correlations between NDVI in previous season and summer temperature show more complex| and the lagged responses of temperature to vegetation are weaker compared with precipitation| and they are possibly related to the global warming which partly cover up the correlations. 5968,2003,2,4,Nitrogen and phosphorus resorption efficiency and proficiency in six sub-arctic bog species after 4 years of nitrogen fertilization,1 Plant growth at high-latitude sites is usually strongly nutrient-limited. The increased nutrient availability predicted in response to global warming may affect internal plant nutrient cycling| including nutrient resorption from senescing leaves. 2 The effect of increased N supply (10 g N m(-2) year(-1)) on nitrogen and phosphorus resorption efficiency and proficiency in six sub-arctic bog species| belonging to four different growth-forms| was studied in northern Sweden. 3 We hypothesized that while increased N supply would not affect N or P resorption efficiency| it would lead to lower N resorption proficiency (higher N concentrations in leaf litter) and higher P resorption proficiency (lower P concentrations in leaf litter). We also investigated whether the basis on which resorption was expressed (leaf mass| leaf area or unit leaf) influenced the patterns observed. 4 Contrasting with our hypothesis| a general trend of decreased N resorption efficiency occurred in response to increased N supply| but the expected decrease in N resorption proficiency was seen in all species except Betula nana. 5 P resorption efficiency did not change in four species (B. nana| Empetrum hermaphroditum| Eriophorum vaginatum and Rubus chamaemorus) but it decreased in Andromeda polifolia| and increased in Vaccinium uliginosum. P resorption proficiency showed the expected increase in only two species (B. nana and V. uliginosum). 6 Apart from P resorption efficiency| the different calculation methods generally produced similar responses of resorption efficiency and proficiency to N supply. 7 Increased N supply at high-latitude sites clearly leads to more N being returned to the soil through leaf litter production. However| decomposition of such litter will probably become P-limited. 8 Considerable interspecific differences in nutrient resorption proficiency were found| indicating that long-term changes in vegetation composition need to be considered when evaluating plant-mediated effects on ecosystem nutrient cycling in response to increased nutrient supply. 2744,2003,2,2,Nitrous oxide emissions from grass swards during the eighth year of elevated atmospheric pCO(2) (Swiss FACE),Emissions of N-2 O were measured during the growth season over a year from grass swards under ambient (360 muL L-1 ) and elevated (600 muL L-1 ) CO2 partial pressures at the Free Air Carbon dioxide Enrichment (FACE) experiment| Eschikon| Switzerland. Measurements were made following high (56 g N m(-2) yr(-1) ) and low (14 g N m(-2) yr(-1) ) rates of fertilizer application| split over 5 re-growth periods| to Lolium perenne | Trifolium repens and mixed Lolium /Trifolium swards. Elevated p CO2 increased annual emissions of N-2 O from the high fertilized Lolium and mixed Lolium /Trifolium swards resulting in increases in GWP (N-2 O emissions) of 179 and 111 g CO2 equivalents m(-2) | respectively| compared with the GWP of ambient p CO2 swards| but had no significant effect on annual emissions from Trifolium monoculture swards. The greater emissions from the high fertilized elevated p CO2 Lolium swards were attributed to greater below-ground C allocation under elevated p CO2 providing the energy for denitrification in the presence of excess mineral N. An annual emission of 959 mg N-2 O-N m(-2) yr(-1) (1.7% of fertilizer N applied) was measured from the high fertilized Lolium sward under elevated p CO2 . The magnitude of emissions varied throughout the year with 84% of the total emission from the elevated p CO2 Lolium swards measured during the first two re-growths (April-June 2001). This was associated with higher rainfall and soil water contents at this time of year. Trends in emissions varied between the first two re-growths (April-June 2001) and the third| fourth and fifth re-growths (late June-October 2000)| with available soil NO3 (-) and rainfall explaining 70%| and soil water content explaining 72% of the variability in N-2 O in these periods| respectively. Caution is therefore required when extrapolating from short-term measurements to predict long-term responses to global climate change. Our findings are of global significance as increases in atmospheric concentrations of CO2 may| depending on sward composition and fertilizer management| increase greenhouse gas emissions of N-2 O| thereby exacerbating the forcing effect of elevated CO2 on global climate. Our results suggest that when applying high rates of N fertilizer to grassland systems| Trifolium repens swards| or a greater component of Trifolium in mixed swards| may minimize the negative effect of continued increasing atmospheric CO2 concentrations on global warming. 6102,2003,2,4,Nitrous oxide flux to the atmosphere from the littoral zone of a boreal lake,[1] The surface-atmospheric exchange of nitrous oxide (N2O) was investigated in the vegetated littoral zone of a eutrophied midboreal lake (Lake Kevaton| Finland) with a static chamber technique. During a dry summer (three to six samplings per site)| the meadow site and two marsh sites in the temporarily flooded eulittoral zone and the Phragmites australis-dominated site in the continuously flooded infralittoral zone had mean daytime N2O-N emissions from 11 +/- 7 to 22 +/- 7 mug m(-2) h(-1)| whereas the Nuphar lutea-dominated site in the infralittoral zone had a mean N2O flux close to zero. During a wet summer (13-14 samplings per site)| the mean daytime N2O-N fluxes ranged from 4 +/- 1 to 15 +/- 5 mg m(-2) h(-1) at the three eulittoral sites and were negligible at the two infralittoral sites. The littoral zone occupied 26% of the lake area but was estimated to account for most of the N2O emissions from the lake. The studied eulittoral zone| which did not have adjacent nitrogen fertilization| exhibited higher N2O emissions during the summer than seen in northern natural ecosystems in general| including peatlands| forests| and the pelagic regions of lakes. Thus in lake-rich landscapes the littoral zone and other lake-associated wetlands must be considered as potential sources of atmospheric N2O. An assessment of their atmospheric importance requires further data on the N2O fluxes and their regulation in different littoral areas and on the total littoral coverage| neither of which is yet available. 6274,2003,4,4,Nitrous oxide| dinitrogen and methane emission in a subsurface flow constructed wetland,N2O| N-2 and CH4 fluxes were measured from a horizontal subsurface flow (HSSF) constructed wetland (CW) for wastewater treatment in Estonia. The closed chamber method was used in the field and the He-O method (intact soil core analyses) in the lab throughout the period from October 2001 to June 2002. The average flux of N2O-N| N-2-N and CH4-C from various microsites ranged from 0.1 to 59| 4.1 to 1|458 and -0.04 to 2|094 mg m(-2) d(-1)| respectively. A significantly higher flux of N2O was found in chambers installed above the inlet pipes| while the methane flux was higher in the inlet part of the bed with wetter conditions. The groundwater table significantly correlates with gas emission rates of all the gases studied; N-2 emission was enhanced by higher temperature of wastewater. PO43- and NH4+ content significantly enhanced| and NO2- and NO3- content inhibited| both N2O and CH4 fluxes. NH4+ showed a negative correlation with N-2 flux. Nitrification and denitrification are the main processes of the N removal in the CW covering 42.9%. The specific global warming potential was highest in the wet bed and lowest in the dry bed with lowered water table (32 and 9g CO2 pe(-1) d(-1)| respectively). 6310,2003,3,4,Normalisation figures for environmental life-cycle assessment The Netherlands (1997/1998)| Western Europe (1995) and the world (1990 and 1995),Normalisation provides a measure of the relative contribution from a product system to one or more environmental problems. Total yearly emissions for a reference year in a reference region are normally used to calculate normalisation figures. This paper provides up-to-date normalisation figures for the Netherlands in 1997/1998| Western Europe in 1995 and the world in 1990 and 1995. Impact categories considered were depletion of abiotic resources| land competition| global warming| stratospheric ozone depletion| acidification| eutrophication| photochemical ozone formation| radiation and toxicity. In all cases| a limited set of emissions or extractions are dominant contributors to the normalisation scores. Although much effort was spent on collecting emissions data and characterisation factors| particularly normalisation scores for radiation and toxicity remain considerably uncertain. (C) 2003 Elsevier Science Ltd. All rights reserved. 5992,2003,4,4,North Pacific Intermediate Water response to a modern climate warming shift,[ 1] Oceanic observations and an isopycnal ocean model simulation are used to investigate the response of North Pacific Intermediate Water ( NPIW) to atmospheric forcing associated with the well- known 1976 - 1977 climate regime shift to a warm regime. The model reproduces numerous features of NPIW including distribution| depth| temperature| and salinity. Changes in NPIW associated with the climate shift in the California coastal region were strongly influenced by an anomalous poleward flow at depth ( 300 - 1100 m). This current transports old| high salinity| low oxygen intermediate waters from the northern tropics to the midlatitudes. For depths below the mixed layer| the model reproduces observed changes in salinity| nitrates| and| to some extent| oxygen| thus suggesting that advective/ diffusive processes are dominant in determining their concentrations below 300 m| isolated from the surface effects of direct atmospheric forcing and biological processes. These changes are structurally similar to those induced by much larger| abrupt climate changes at the end of the last glacial episode. 6259,2003,2,4,Northern hemisphere photosynthetic trends 1982-99,We examined trends in the averaged May-September AVHRR normalized difference vegetation index (NDVI) from 1982 to 1999 for the northern hemisphere. NDVI is closely related to the amount of absorbed photosynthetically active radiation; hence| trends in NDVI reflect trends in photosynthetic activity of land-surface vegetation. Linear and nonlinear trend analysis techniques were applied to four differently processed and corrected Advanced Very High Resolution Radiometer (AVHRR) NDVI data sets. The results were compared in order to evaluate the effects of trends in NDVI unrelated to vegetation activity. We consistently found significant positive trends in averaged NDVI for latitude bands above 35degreesN in all but one data set; this one data set lacked corrections for sensor drift and instrument calibration. An impressive improvement in data quality was achieved by applying calibration and corrections for atmospheric effects. Conservative estimates of the trends over the 1982-99 period range from 0.0015 to 0.0045 NDVI units year(-1) for global latitude bands from 35 to 75degreesN| with trends generally higher in the 1990s than in the 1980s; trends in NDVI were larger than trends explained by artefacts. In the 1980s| North American and Eurasian trends were roughly comparable| whereas in the 1990s the North American trends were generally higher. A pixel-level analysis shows the trends to be widespread| with large areas of Canada| Europe and northern Asia experiencing significant positive increases across all vegetated landcovers. 2756,2003,4,4,Northern hemispheric NDVI variations associated with large-scale climate indices in spring,Large-scale atmospheric systems| such as the Southern Oscillation| North Atlantic Oscillation| and so on| are important climatic change indicators over the northern hemisphere. These systems play essential roles in regional-to-continental scale climate fluctuation and vegetation activity in response to global change. Using the Pathfinder AVHRR NDVI (Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index) data for the period 1982-2000| the authors investigated the relationship of the inter-annual variations of spring NDVI to nine large-scale climate indices. On average| 57.2% of the satellite-sensed NDVI variance was explained. These climate indices also accounted for a large portion of the trends in NDVI as observed in five regions| namely| north-west North America (climate-related trend was 18.2%/10 years)| south-eastern North America (5.8%/10 years)| Europe (6.9%/10 years)| high-latitude Asia (12.4%/10 years)| and East Asia (8.0%/10 years). The results are useful for understanding and predicting the regional-to-continental NDVI variations in response to global climate change. 6199,2003,3,3,Numerical analysis of the source-sink alternation of composite global warming potential of the paddy ecosystem in the Yangtze Delta,By coupling the biogeochemical model With plant ecological model| a model Was established to reveal the principle of the composite global warming potential transformation in the paddy ecosystem. Validation of the model with the observed data indicated that|the model can simulate both the crop growth processes and emissions of CH4| and N2O accurately. Some numerical analyses were made to identify the impacts of different fertilizer application on assimilation Of CO2 and emissions of CH4 and N2O| and the transformation principle of the composite global warming potential. Based on the results of the numerical analysis| the source-sink alternation of composite global warming potential in the paddy ecosystem was discovered| and some new conceptions of fertilizer index such as maximum-sink fertilizer| zero-emission fertilizer are put forward in this paper. The fertilizer scheme for Yangtze Delta was proposed to provide the important scientific basis for a sustainable agriculture in this region. 6300,2003,3,2,Oceanic iron fertilization: one of strategies for sequestration atmospheric CO2,Carbon cycle is connected with the most important environmental issue of Global Change. As one of the major carbon reservoirs| oceans play an important part in the carbon cycle. In recent years| iron seems to give us a good news that oceanic iron fertilization could stimulate biological productivity as CO2 sink of human-produced CO2. Oceanic iron fertilization experiments have verified that adding iron into high nutrient low chlorophyll (HNLC) seawaters can increase phytoplankton production and export organic carbon| and hence increase carbon sink of anthropogenic CO2| to reduce global warming. In sixty days| the export organic carbon could reach 10 000 times for adding iron by model prediction and in situ experiment| i.e. the atmospheric CO2 uptake and inorganic carbon drawdown in upper seawaters also have the same magnitude. Therefore| oceanic iron fertilization is one of the strategies for increasing carbon sink of anthropogenic CO2. The paper is focused on the iron fertilization| especially in situ ocean iron experiments in order that the future research is more efficient. 2788,2003,3,3,Offsetting global CO2 emissions by restoration of degraded soils and intensification of world agriculture and forestry,Increase in atmospheric concentration Of CO2 from 285 parts per million by volume (ppmv) in 1850 to 370ppm in 2000 is attributed to emissions of 270+/-30 Pg carbon (C) from fossil fuel combustion and 136+/-55 Pg C by land-use change. Present levels of anthropogenic emissions involve 6.3 Pg C by fossil fuel emissions and 1.8 Pg C by land-use change. Out of the historic loss of terrestrial C pool of 136+/-55 Pg| 78+/-12 Pg is due to depletion of soil organic carbon (SOC) pool comprising 26+/-9 Pg due to accelerated soil erosion. A large proportion of the historic SOC lost can be resequestered by enhancing the SOC pool through converting to an appropriate land use and adopting recommended management practices (RMPs). The strategy is to return biomass to the soil in excess of the mineralization capacity through restoration of degraded/desertified soils and intensification of agricultural and forestry lands. Technological options for agricultural intensification include conservation tillage and residue mulching| integrated nutrient management| crop rotations involving cover crops| practices which enhance the efficiency of water| plant nutrients and energy use| improved pasture and tree species| controlled grazing| and judicious use of inptus. The potential of SOC sequestration is estimated at 1-2 Pg C yr(-1) for the world| 0.3-0-6 Pg C yr(-1) for Asia| 0.2-0-5 Pg C yr(-1) for Africa and 0.1-0.3 Pg C yr(-1) for North and Central America and South America| 0.1-0.3 Pg C yr(-1) for Europe and 0.1-0.2 Po C yr(-1) for Oceania. Soil C sequestration is a win-win strategy; it enhances productivity| improves environment moderation capacity| and mitigates global warming. Copyright) (C) 2003 John Wiley Sons| Ltd. 6154,2003,2,4,On destructive Canadian prairie windstorms and severe winters - A climatological assessment in the context of global warming,Raw data on tornadoes and other destructive windstorms in the provinces of Alberta and Saskatchewan| Canada| are analyzed for spatial variations and time trends. All storms and a subclass of intense storms are analyzed separately. Statistics Canada agriculture census data are used to correct storm frequencies for the absence of reports from unoccupied land| for sampling network drift| and for changes in farm numbers and sizes. These corrections eliminate an apparent tornado spatial frequency maximum in central Alberta and reveal a minor temporal frequency maximum from 1906 to 1940 followed by no apparent trend in time for all intense storms. The frequencies of reports of severe winters in rural community histories of Alberta and Saskatchewan are compared with mean winter temperatures at Edmonton and with a severe winter index derived from temperature and snowfall data. All temperature data were corrected for urban heat island warming by an adaptation of Oke's proposed logarithmic relation between heat island intensity and urban population. The index identifies in correct order of importance the three most frequently mentioned severe winters of 1907| 1920 and 1936. Ten-year averages of mean winter temperatures and the severe winter index from 1882 to 2001 seem to show wavelike time changes rather than a l