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  • 2021 SkS Weekly Climate Change & Global Warming Digest #1

    Dr. S. Jeevananda Reddy at 17:47 PM on 11 January, 2021


    Global Warming: It is an estimate of the annual average part of temperature trend. The trend of 1880 to 2010 is 0.6oC per century in which global warming component is 0.3oC – 1951 to 2100 is 0.45oC – according to linear trend. But in reality it is not so as the energy component is constant over which superposed sunspot cycle. However, the reliability depends up on the data used. For example number of stations in around 1850 were < 100 and by around 1980 [started satellite data collection started around this time] they were more than 6000 and with the availability of satellite data the number of stations drastically come down to around 2500. The satellite data covered both urban-heat-island effect and rural-cold-island effect and showed practically no trend – US raw data series also showed this. However, this data was removed from internet [Reddy, 2008 – Climate Change: Myths & Realities, available on line] and replaced with new adjusted data series that matches with ground data series. Here cold-island effect is not covered. With all this, what I want say is warmings associated with solar power plants is added to global warming. How much?? This needs collection of data for all the solar power stations. Met station covers a small area only but acts like UHI effect – I saw a report “surface temperatures in downtown Sacramento at 11 a.m. June 30, 1998 – this presents high variation from area to area based on land use [met station refers to that point only]. So, solar wind power plants effect covers similar to heatwaves and coldwaves. Here general Circulation Pattern plays main role.

    Nuclear Power: Nuclear power production processes contribute to “global warming process” while hydropower production processes contribute to “global cooling process”; the nuclear power production processes don’t fit into “security, safety & economy” on the one hand and on the other “environment & social” concepts; unlike other power production processes, in nuclear power production process different stages of nuclear fuel cycles are counted as separate entities while assessing the cost of power per unit and only the power production component is accounted in the estimation of cost of power per unit; carbon dioxide is released in every component of nuclear fuel cycle except the actual fusion in the reactor. Fossil fuels are involved in the mining-transport-milling conversion-processing of ore-enrichment of the fuel, in the handling of the mill tailings-in the fuel can preparation-in the construction of plant and it decommissioning-demolition, in the handling of the spent waste-in its processing and vitrification and in digging the hole in rock for its deposition, etc. and in the manufacturing of necessary required equipment in all these stages and thus their transportation. In all these stages radiological and non-radiological pollution occurs – in the case of tail pond it runs in to hundreds of years. Around 60% of the power plant cost goes towards the equipment, most of which is to be imported. The spent fuel storage is a critical issue, yet no solution was found. Also the life of reactors is very short and the dismantling of such reactors is costly & risky, etc., etc.

    Michael Sweet/ Negelj

    In 70&80s I worked and published several articles relating to radiation [global solar and net and evaporation/evapotranspiration] – referred in my book of 1993 [based on articles published in international and national journals]. Coal fired power plants reduces ground level temperature by reducing incoming solar radiation. In the case of Solar Panels create urban heat island condition and thus increases the surrounding temperature. In both the cases these changes depends upon several local conditions including general circulation patterns. Ground condition plays major role on radiation at the surface that define the surface temperature [hill stations, inland stations & coastal stations] – albedo factor varies. Also varies with soil conditions – black soil, red soil. Sea Breeze/land breeze – relates to temperature gradient [soil quickly warm up and quickly release the heat and water slowly warm up and slowly release heat] and general circulation pattern existing in that area plays the major role in advection.

    Response to Moderator

    See some of my publications for information only:

    Reddy, S.J., (1993): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries, Books, 205p; Book Review appeared in Agricultural and Forest Meteorology, 67 (1994):325-327.
    Reddy, S.J., (2002): Dry-land Agriculture in India: An Agroclimatological and Agrometeorological Perspective, BS Publications, Hyderabad, 429.
    Reddy, S.J., (2008): Climate Change: Myths & Realities, Books, 176.
    Reddy, S.J., (2016): Climate Change and its Impacts: Ground Realities. BS Publications, Hyderabad, 276.
    Reddy, S.J., (2019a): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries [2nd Edition]. Brillion Publishing, New Delhi, 372p.

    2.1.2 Water vapour

    Earth’s temperature is primarily driven by energy cycle; and then by the hydrological cycle. Global solar radiation reaching the Earth’s surface and net radiation/radiation balance at the Earth’s surface is generally estimated as a function of hours of bright Sunshine. Total cloud cover [average of low, medium & high clouds] has a direct relation to hours of bright Sunshine (Reddy, 1974). Cube root of precipitation showed a direct relation to total solar radiation and net radiation (Reddy, 1987). In all these latitude plays major role (Reddy & Rao, 1973; Reddy, 1987). Evaporation presents a relation with net and global solar radiation (Reddy & Rao, 1973) wherein relative humidity plays an important role that reduces with increasing relative humidity. If ‘X’ is global solar radiation received under100% relative humidity then with the dryness [with relative humidity coming down] it may reach a maximum of 2X; and under net radiation also with increasing relative humidity net radiation is reduced. That means water vapour in the atmosphere is the principal component that controls the incoming and outgoing radiation and thus temperature at the Earth’s surface. Thar Desert presents high temperature with negligible water vapour in the atmosphere as maximum energy reaches the earth’s surface. However, these impacts differ under inland (dryness), hill (declining temperature with height – lapse rate) & coastal (wetness) locations and sun’s movement (latitude and declination of the Sun — seasons) (Reddy & Rao, 1973). IPCC integrated these under “climate system” and the advective condition by general circulation pattern [GCP].
    Cold-island effect [I coined this, see Reddy (2008)] is part of human induced climate change associated with changes in land use and land cover. Since 1960’s to meet the food needs of ever increasing population, started intensive agriculture – conversion of dryland to wetland; & creation of water resources; etc. In this process increased levels of evaporation and evapotranspiration contributed to raise in water vapour up to around 850 mb levels in the lower atmosphere. Unusual changes in water vapour beyond 850 mb level [for example at 700 mb level] become a cause for thunderstorm activity (Reddy & Rao, 1978). Wet bulb temperature (oC) at the surface of the Earth provides the square root of total water vapour (g/cm2) in the vertical column of the atmosphere; and also wet bulb temperature (oC) is a function of dry bulb temperature (oC), relative humidity (%) and square root of station level pressure (height) relative to standard value in mb [p/1060] (Reddy, 1976). Thus, unlike CO2, water vapour presents a short life with steadily increasing with land use and land cover changes. However, met network in this zones have been sparse and thus the cold island effect is not properly accounted under global average temperature computations. Though satellite data takes this in to account, this data series were withdrawn from the internet and introduced new adjusted data series that matches with adjusted ground data series. Annual state-wise temperature data series in India wherein intensive agriculture practices are existing, namely Punjab, Haryana & UP belt, showed decreasing trend in annual average temperature – cooling. Some of these are explained below:

    Reddy (1983) presented a daily soil water balance model that computes daily evapotranspiration, known as ICSWAB Model. The daily soil water balance equation is generally written as:

    ▲Mn = Rn – AEn – ROn - Dn

    In the above equation left to right represent the soil moisture change, rainfall or irrigation, actual evapotranspiration, surface runoff and deep drainage on a given day (n). The term Actual Evapotranspiration [AEn] is to be estimated as a function of f(E), f(S) & f(C), wherein they represent functions of evaporative demand on day n, soil & crop factors, respectively. As these three factors are mutually interactive, the multiplicative type of function is used.

    AEn = f(En) x f(S) x f(C)

    However, the crop factor does not act independently of the soil factor. Thus it is given as:

    AEn = f(En) x f(S,C) and f(S,C) = K x bn

    Where f(S,C) is the effective soil factor, K = soil water holding capacity [that varies with soil type] in mm and bn is the crop growth stage [that vary with crop & cropping pattern] factor that varies between 0.02 to 0.24 — fallow to full crop cover conditions (with leaf area index crossing 2.75). Evaporative demand is expressed by the terms evaporation and/or evapotranspiration. Evaporation (E) and evapotranspiration (PE) are related as:

    PE = 0.85 x E [with mesh cover] or = 0.75 x E [without mesh cover].

    However, the relationship holds good only under non-advective conditions [i.e., under wind speeds less than 2.5 m/sec]. Under advective conditions E is influenced more by advection compared to PE. In the case of PE, by definition, no soil evaporation takes place and thus PE relates to transpiration only – where the crop grows on conserved soil moisture with negligible soil evaporation. With the presence of soil evaporation, the potential evapotranspiration reaches as high as 1.2 x PE or E with mesh cover. McKenney & Rosenberg (1993) studied sensitivity of some potential evapotranspiration estimation methods to climate change. The widely used methods are Thornthwaite and Penman presented 750 mm and 1500 mm wherein Thornthwaite method is basically uses temperature and Penman uses several meteorological parameters (Reddy, 1995).
    In this process the temperature is controlled by solar energy but moisture under different soil types [water holding capacity] it is modified. This modified temperature cause actual evapotranspiration and thus water vapour. This is a vicious circle. For example average annual temperature in red soils Anantapur it is 27.6oC; in deep black soils Kadapa it is 29.25oC & in medium soils Kurnool it is 28.05oC. That means, local temperature is controlled by soils.
    Reddy (1976a&b) presented a method of estimating precipitable water in the entire column of the atmosphere at a given location using Wet Bulb Temperature. The equations are given as follows:

    Tw = T x [0.45 + 0.006 x h x (p/1060)1/2]

    W = c’ x Tw2

    Where T & Tw are dry and wet bulb temperatures in oC; h is the relative humidity in %; p is the annual normal station level pressure in mb [1060 normal pressure in mb, a constant] ; W is the precipitable water vapour in gm/cm2 and c’ is the regression coefficient.
    WMO (1966) presented methods to separate trend from natural rhythmic variations in rainfall and assessing the cycles if any. (Late) Dr. B. Parthasarathy from IITM/Pune used these techniques in Indian rainfall analysis. Reddy (2008) presented such analysis with global average annual temperature anomaly data series of 1880 to 2010 and found the natural cycle of 60-years varying between -0.3 to +0.3oC & trend of 0.6oC per century [Reddy, 2008]. This is based on adjusted data series but in USA raw data [Reddy, 2016] there is no trend. The hottest daily temperature data series of Sydney in Australia shows no trend [Reddy, 2019a]. Thus, the trend needs correction if the starting and ending point parts are in the same phase of the cycle – below and below or above and above the average parts. During 1880 to 2010 period two full 60-year cycles are covered and thus, no need to correct the trend as the trend passes through the mean points of the two cycles.

    3.2.4 What is global warming part of the trend?

    According to IPCC AR5, this trend of 0.6oC per century is not global warming but it consists of several factors:
    a. More than half is [human induced] greenhouse effect part:
    i. It consists of global warming component & aerosols component, etc. If we assume global warming component alone is 50% of the total trend, then it will be 0.3oC per Century under linear trend;
    ii. Global warming starting year is 1951 & thus the global warming from 1951 to 2100 [150 years] is 0.45oC under linear trend;
    iii. But in nature this can’t be linear as the energy is constant and thus CSF can’t be a constant but it should be decreasing non-linearly;
    iv. Under non-linear condition by 2100 the global warming will be far less than 0.45oC and thus the trend will be far less than half;
    b. Less than half the trend is ecological changes [land use and land cover change] part – mostly local & regional factors:
    i. This consists of urban-heat-island effect and rural-cold-island effect;
    1. Urban-heat-island effect – with the concentrated met network overestimates warming;
    2. Rural-cold-island effect – with the sparse met network underestimates cooling;

    2.2.1 Uncertainty on “Climate Sensitivity Factor”

    The word “climate Crisis” is primarily linked to global warming. To know whether there is really global warming, if so how much, climate sensitivity factor plays the main role. Climate sensitivity is a measure [oC/(W/m2)] – how much warming we expect (both near-term and long-term) for a given increase in CO2? According to Mark, D. Zilinka (2020), “Equilibrium climate sensitivity, the global surface temperature response to the CO2 doubling, has been persistently uncertain”.
    Recent modelling data suggests the climate is considerably more sensitive to carbon emissions than previously believed, and experts said the projections had the potential to be “incredibly alarming”, though they stressed further research would be needed to validate the new numbers. Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, said. “Climate sensitivity is the holy grail of climate science. It is the prime indicator of climate risk.
    The role of clouds is one of the most uncertain areas in climate science because they are hard to measure and, depending on altitude, droplet temperature and other factors can play either a warming or a cooling role. For decades, this has been the focus of fierce academic disputes. Catherine Senior, head of understanding climate change at the Met Office Hadley Centre, said more studies and more data are needed to fully understand the role of clouds and aerosols. With this vital disputes how anyone can say there is global warming without solving this issue; so I said “global warming hysteria factor is climate crisis”.


  • Is Nuclear Energy the Answer?

    barry at 01:44 AM on 16 June, 2019


    You are staing that unsuported statements will be struck.

    I have not disputed Abbotts numbers, only their interpretation,

    if you wish to stick with those so be it 

    1/ Abbott has used a buffer zone in his calculation and a single occupancy to calculate his area.  All I have pointed out is that nuclear sites nowerdays have multiple occupancy Other peole have used Abbotts density to erroneous conclusions. Indeed M sweet states multiple occupancy is used ' but sticks with Abbotts density figures Ah the reference!  other commentators are excempt

    " no citation needed."  - M Sweet

    Neverthless here is the one that Abbott cites as his source, stating clearly that most of the area taken by abbott is due to a buffer zone and that the area requirement can be reduced to a fraction using multiple occupancy which is the norm.  There is no use citing US because on multiple occupancy as they have only built one facilty (NEF in New Mexico) since the 3 mile island incedent. (


    (ref 6 of Abbott)

    2/ Abbott quotes materials that are used in nuclear reactors . I have pointed out that a number of these are not essential materials . Abbotts reply to me was that they were examples of materials used in a reactor. 

    M Sweet has helpfully provided a note on this matter in which control rods can be made ith halfnium as a very minor constiuent and completly without halfnium. Your requst to provide a reference for somthing not to used is rather difficlt. It is like I cannot prove the absence of Big Fot nor the Loch Ness monster. What I can state is that Halfnium is used as a neutron absorber, which Boron is the normal civilian material for this use and as MS reference shows civilian control rods contain boron.  As I stated before

    "as for hafnium in civilian reactors I stand by it that it is currently not used to any significant extent"  M Sweet has atated that some halfnium is used but in no way does this assetrion that I an wrong hold water.

    "Apparently Westinghouse did not get the memo. Westinghouse was one of the largest manufactures of nuclear plants in the world and all of their control rods contain Hafnium."   no Michael they can also make them without halfnium so halfniun is not essential control rods are perfectly functional without halnium


    "Westinghouse began developing BWR control rods in the mid-1960s. The first control rod, CR 70, was in operation in a BWR plant in 1970. After 45 years, many original rods are still in operation. A vast majority of hafnium-tipped rods (CR 82), the first to be used in the United States in 1983, are still in operation. The CR 82M-1 design was introduced in 1995. The main feature of the CR 82M-1 rod is the change of structural material to 316L stainless steel with high resistance to SCC and a very low-cobalt content. Westinghouse has delivered more than 6,700 BWR control rods worldwide. Out of these, more than 2,300 are the CR 82M-1 design. Westinghouse BWR control rods are licensed in the United

    Mr Sweet you citation does not support your assertion that "Westinghouse was one of the largest manufactures of nuclear plants in the world and all of their control rods contain Hafnium."  only about a third of them.

    Moderator you critcise people for not providing references, what do you do when these references are mis quoted?

    It is only an exmple of Gish Gallop

  • CO2 effect is saturated

    Geologist for a change at 20:43 PM on 3 January, 2019

    Goodbye man-made global warming? As an independent (i.e. impartial) consulting geologist (doctorate in sedimentary geology) with 35 years of experience, having conducted an unpaid (impartial) full-time 3-year (since Nov 2015; continuing) review of the literature from ALL scientific disciplines relevant to climate- and sea-level change (geology, archaeology, physics, astrophysics, oceanography, meterorology, etc, etc), here are my main conclusions:

    (1) There's obviously no doubt that Earth has warmed since thermometer measurements began in the 1800s (HadCRUT data; and online NASA/GISS online charts [yearly, monthly, and others], updated every few weeks). However, Earth began COOLING in February 2016 (NASA/GISS monthly chart). This cooling already exceeds all other measured coolings since 1995, in both duration (nearly 3 years so far) and magnitude (0.5 degrees C, fully one-third of IPCCs dreaded '1.5 degrees C by 2100', but in the wrong direction) ...

    (2) Warming was driven by increasing solar-MAGNETIC output (controlling cosmic rays, therefore cloudiness; Svensmark's breathtakingly elegant theory), nothing to do with mankind's CO2 emissions which just happened, by pure (bad) luck, to grow during a solar upswing (rather than downswing), a ghastly coincidence; the reverse was about equally likely, 50:50.

    (3) Changes in temperature are lagging about 25 years behind changes in solar-magnetic output, due to ocean thermal inertia (google it), dismissed by IPCC.

    (4) Sea level is about to rise about 3 metres (sic), before 2100, driven by the increase in solar-magnetic output (up until its 1996 peak), its effect on sea level delayed a further 20 years (approx.; i.e. total sea-level lag is about 45 years) due to ocean 'conveyor-belt' circulation (also ignored by IPCC) delaying the arrival at Antarctica of 'solar-overwarmed' Atlantic surface water, via downwelling and southward mid-depth flow (AMOC). The floating ice shelves buttressing Antarctic on-land glaciers are NOW disintegrating at an accelerating rate (led by Pine Island, Thwaites and Totten), so catastrophic glacier failure by MISI and/or MICI is likely to begin within a decade, raising sea level by at least 3m within about 50 years. It's unstoppable.

    Am I right? We'll know very soon. Regarding solar control of global temperature, the next two years will tell: I predict continued cooling, so keep a close eye on that NASA temperature chart. Regarding sea level, we'll know within 10 years, possibly much sooner: I predict the rate of sea-level rise, currently a trivial 3mm/year, but already increasing exponentially, will be at least ten times higher (3cm/year) by 2030, if not 2025. Watch NASA's online sea-level chart, updated every few months.

    See my 20 ResearchGate contributions, mostly one-page items or single figures, fully self explanatory ...

  • 2018 SkS Weekly Climate Change & Global Warming Digest #51

    MA Rodger at 01:08 AM on 25 December, 2018

    There was a second comment from Thomas Thorne that has been disappeared. It did try to provide some evidential basis for the assertions being made @1. It wasn't particularly exact in doing this. There was an alleged "UN in 1989" talking about catastrophe by 2000 and also a reference to Al Gore and catestrophic sea level rise. It seems both these 'predictions' concern SLR. The 1989 UN 'prediction' came from a 'Noel Brown, director of the New York office of the U.N. Environment Program, or UNEP.' Now bear in mind that this is coincidental with Montreal and the threat from CFC-caused AGW was as big as was CO2 back then. Even so, the predicted 1 to 7 degree in 30 years temperature increase (Fahrenheit) has happened. The "by 2000" comment was about SLR - "entire nations could be wiped off the face of the Earth by rising sea levels if the global warming trend is not reversed by the year 2000." They are, of course small low-lying nations and I would ahve thought the warming by 1989 was probably enough to do the job without a further 10-years of AGW.

    Myself, I have been bashing on about AGW since 1995. The requirement for CO2 back then was a reduction of 50% by 2050. That has since become 80% and now 100%. The need for action prior to that was always expressed as a need to see CO2 emissions peak by 2020. I don't think that has ever changed. So from my memory the idea that "the IPCC ... have been making these 10-12 year claims for almost 30 years now," is a gross misrepresentation. The IPCC has been tightening the requirement, not the opposite which would have been the case if allowing deadlines to float along, always 10 years in the future.

  • COP24: UN climate change conference, what’s at stake and what you need to know

    scaddenp at 10:23 AM on 6 December, 2018

    juddb. Take a long look at the global temperature record. It consists of pronounced up/down wiggles following at upward trend. The trend is climate - 30 year average - while the wiggles are "weather". Those wiggles are the El Nino/La Nina (ENSO) cycle which is chaotic and so far defies any long term prediction. Record temperatures are always set during an El Nino - which last peaked in Apr 2016. You expect temperatures to decline after that. You wont get a new temperature record till the next big El Nino. Climate models cannot pick El Ninos; what they can do pick the trend. Focus on that. The ENSO cycle is just about redistribution of heat on an unevenly heated, wet planet. In the cool La Nina phase heat is being buried in the ocean. In El Nina, that surfaces and heats the atmosphere.

    How much lower? We havent had a strong La Nina since apr 2016, it mostly neutral but 70% chance of a weak El Nino in next few months so it will likely go back again. If you look at previous strong La Nina (2011 was a doozy), you will get an idea of far it can go down.  Please lets not have a repeat of the "Global warming stopped in 1998, 1995, 2002, 2007, 2010, ????" meme.

  • Climate Science Denial Explained: The Denial Personality

    chapeaured at 01:33 AM on 30 April, 2018

    I think the article and the comments on the article all miss the basic cause of the problem. And the basic cause is one that almost no one knows about because almost no one wants to talk about it.
    Nearly all strong deniers are strong conservatives and they are genetically predisposed to be conservatives. They are genetically predisposed to be xenophobic, more religious, more repressive of women’s rights, much less concerned with fairness/equity and they hold a darker view of human nature than their counterparts. Conservatives are much less open to new experiences of any type. Conservatives are much more prone to authoritarianism (the opposite of scientific thought) and to group think. Liberals have the opposite traits to all of the conservative traits. Individuals are genetically predisposed to be conservative or liberal. Genetics is responsible for about half, or just a bit more that half, of our political orientations.
    Conservatives believe in the prevailing conservative ideologies of the societies they live in in the same way that religious people believe in the teachings of their religious group. One of the most amaziong findings is that strong conservatives are the least capable of thinking logically/critically/rationally about anything that comes into conflict with their conservative ideological beliefs.
    Conservatives perceive correctly that if man-caused global warming is true, then government needs to play a key or lead role in dealing with the problem. Much worse, horror of horrors, the major governments of the world all have to collaborate together to solve the problem. That is totally anathema to the prevailing free market belief system. So therefore, man-caused global warming cannot be true. Therefore, it is not true. It is a hoax.
    It is the best educated conservatives that are the least capable of thinking critically about global warming. Being better educated they have a much greater pool of concepts and facts to draw upon to rationalize their beliefs. And there is no equivalence on the liberal side. It is the best educated liberals who are the most capable of thinking critically about global warming.
    I am a very strong liberal. In August 1995, I joined an Internet discussion group of American foresters that for some reason unknown to me, was dominated by very strong conservatives (Austrian Hayek school of economics, Libertarians and the like). They all believed that global warming was a hoax. They believe that we have no significant environmental problems of any type. I had never encountered people like this before. I didn’t know much about global warming at the time, so for about four years, I would check out their sources – and I found them all to be bogus or questionable. Then for another 10 years or more, I argued directly with them. The stronger the scientific evidence I presented them with, the more it reinforced their beliefs. I tried a bit of everything. I came to believe that they were sincere in their beliefs. I finally came to the conclusion that there was no reasoning with them. I gave up.
    Then, about two years later, I read “The Republican Brain” by investigative journalist Chris Mooney and he described almost exactly what I had experience. He summarized peer reviewed social sciences research that shows the problem is genetic. Since then, I also read “Our Political Nature” by evolutionary anthropologist Avi Tuschman. Nearly all of what I have written above is a summary of their findings in the two books. Tuschman also goes into what scientists believe to have been the evolutionary selective forces that left us with such genetically defective brains – and the selective forces for the set of characteristics grouped under the heading of “tribalism” are really mind bending.
    Most of this seems overall, very discouraging. I’m still trying to digest what it all means. I see two areas for potential optimism:
    1. Our genetically driven political orientations all lie on a bell curve. Most of us are somewhere in the middle – moderately conservative or moderately liberal. I assume that the closer to the center conservatives are, the more open they are to the environmental influences – the more open they are to evidence and logic and reasoned argument.
    2. Conservatives are much more subject to group think and to belief in the prevailing conservative ideologies of the societies they live in. But those prevailing ideologies do seem to evolve substantially over time. The conservative ideologies of the 1950s in the US probably lie to the left of the Democratic platform of today. The extremist Free Market ideologies now predominate. They can certainly evolve – they can moderate or they can become even more extreme.
    Roy Hagen

  • How to Change Your Mind About Climate Change

    chapeaured at 09:36 AM on 12 February, 2018

    There are major genetic constraints to critical thinking on topics like climate change. For 17 years starting in 1995, I tried to reason with a group of very conservative American foresters in an Internet discussion group called SAFNews that morphed into ForestryFocus. They argued that we have no significant environmental problems at all and that global warming was a hoax. I had assumed that climate change was real, but the conviction of this group took me aback. For about four years, I would look up their sources, and became convinced they were all wrong. Evidence that I would present on anthropogenic global warming only seemed to strengthen their conviction that it was a hoax. I am a very strong liberal and I had never med people like this. I found it very difficult to accept that one could not find a way to reason with these people. I tried every tactic I could think of. After 17 years of trying, I finally came to conclude that they were sincere in their belief and there was no way to change that.

    Then, about two years after giving up, I read “The Republican Brain” by Chris Mooney, and it explained what I had just experienced. The book summarizes peer reviewed research that found that there is a strong genetic influence on our political orientations and that strong conservatives are incapable of thinking rationally/critically/logically about issues that conflict with their conservative beliefs. Conservatives recognize correctly that if global warming were true, then, not only does it necessitate a role for government to intervene in the economy, but, horror of horrors, all the governments in the world need to collaborate together to solve the problem. So therefore, it can’t be true and global warming is a hoax. And the most incredible research finding of all is that it is the best educated conservatives who are the least capable of thinking critically about things that conflict with their beliefs. And there is no equivalence on the liberal side – it is the best educated liberals who are the most capable of thinking critically about things that disagree with their political beliefs.

    More recently, I read the book “Our Political Nature” by evolutionary anthropologist Avi Tuschman. It argues that our genes are responsible for just over half of our political orientations and it goes into what scientists believe the evolutionary selective factors were for our political orientations. Conservatives are genetically predisposed to be more xenophobic, have greater religiosity, to be more repressive of women’s rights, to be less concerned about fairness than liberals and to have a darker view towards human nature. One can clearly see this being played out on the national stage today.
    Roy Hagen

  • CO2 lags temperature

    Tom Curtis at 08:21 AM on 16 February, 2017

    Adri Norse Fire @532, first, let me say you are coping quite well with the language difference given that you are using a machine translator.

    "''What is worse, you ask, "How do they know that CO2 does not come from other sources that also have low levels of radicarbon But or course, Daniel Bailey has already answered that question with 10 lines of evidence.'' He didn't and this answer was not addressed to him"

    On the contrary, five of the ten lines of evidence falsify the theory that the increase in CO2 in modern times is a consequence of increased vulcansim; and a sixth renders it unlikely:

     As fossil fuel and volcanic CO2 are the only C14 - free sources of carbon on the Earth, that precludes the origin being a C14 free source other than fossil fuels.

    I am not sure what you meant by "this answer was not addressed to him" given that the sentence I quoted clearly came from the section of your comment headed "Daniel Bailey".  I assume it is an inaccurate translation.

    "I did not say that CO2 or CH3 does not produce a greenhouse effect, but the feedback effect of CO2 and other minor gases is irrelevant to climate compared to other greenhouse gases."

    It is true that water vapour is a significant feedback on any warming.  However, it contributes approximately 1C of warming for each 1 C contributed from another source.  That means that for the glacial/interglacial cycle, including water vapour, albedo effects will have most likely contributed <30% directly, CO2 and CH4 <25%, with H2O most likely contributing <45%.  Less than, because there are other short term feedbacks that are most likely to contribute about 0.5 C for each 1 C of direct warming, but may contribute 4 times that amount, but may have been a negative feedback.

    Firstly, I will note that 6 - 25% contribution from CO2 and CH4 (once we account for the effect of water vapour) is not a negligible contribution.

    Secondly, I will further note that H2O has a very short time to return to equilibrium in the atmosphere (weeks), so that its total atmospheric contribution is almost entirely governed by temperature.  That means when we wish to determine the effect of an increase in CO2 concentration on the Earth's temperature, we can treat H2O as a feedback - and need not track it independently.  That is particularly important for graphs such as this one:

    It is well known that the direct temperature effect of a change in forcing is about 1 C to 1.2 C per 3.7 W/m^2 change, and hence about 0.8 to 0.9 C for the change in forcing from last glacial maximum to the holocene.  The calculation of the implied sensitivity, therefore, is not an attempt to determine that direct effect, but to determine the result of the direct temperature effect plus all short term feedbacks, including H2O.  That turns out to be about 2.8 C per 3.7 W/m^2.

    Because I (and others) understand the purpose examining the causes of the difference in temperature between the last glacial maximum and the holocene, we do not bother mentioning the details about components of the short term feedbacks.  I will grant that when talking with a popular audience, who are not aware of the reasons for focussing on CO2 and change in glacial ice extent, that is a mistake.  We should clarrify the role of short term feedbacks, and why we are focussing on CO2 (as I have now done).

    "If you like correlations so much why do not you look for some of the temperature and CO2 for the last 10,000 years? Does this correlation count as evidence?"

    First, if you want to be taken seriously in a scientific discussion, don't source evidence from astrology sites, as you have done with that first chart.  Granted the author of that site attributes the chart to a climate scientist (Schoenwiese) without specification as to year, or publication.  Fortunately the chart has been examined as an example of the misuse of scientific charts by climate "skeptics" (Schneider et al 2014).  The chart is from Schoenwiese 1995, and based on Daansgard (1984) (published online in 2013).  Schneider et al (2014) comment:

    "many authors of skeptical media (for example Avery, 2009, and Vahrenholt und Lüning, 2012) fail to mention that this temperature estimate is based on an ice-core record from Greenland and may thus not be representative of global temperatures."

    Of course, in your version it is labelled Northern Hemisphere temperatures, not global temperatures.  The point still stands, however.  A Greenland ice core no more shows Northern Hemisphere temperatures by itself than does a thermometer in Moscow show temperatures in Tucson, Arizona.  It can be used (as Daansgard used it) as an indication of North Atlantic temperatures, but beyond the North Atlantic, its accuracy as a temperature index will rapidly fall.

    Schneider et al go on:

    "Most importantly, in Schönwiese's 1995 version the current and near future temperature changes are included. The recent warming goes far beyond the historic warm periods of the last 12000 years and should therefore have been included in the graph."

    (My emphasis)

    You should recognize that yourself.  Taken at face value, the chart indicates that the Little Ice Age terminated 400 years ago.  If we allow a more recent (circa 1850) termination then we must, according to that chart, acknowledge that for most of the LIA it was as warm as the peak of the Medieval Warm Period; and of course, that temperatures have since risen significantly above that peak.

    Finally, here is a chart which has a fair claim to represent global holocene temperatures (but note caveats):

     Note that 2004 is significantly warmer than any period prior to 1900, and that it has warmed appreciably since then.

    All of this may be a side issue, but I am unsure as to what point you are trying to make with two charts of CO2 concentration over the last 800,000 years, or the chart of CO2 concentration over the Holocene.

    "why the current temperature is 1.5 ° lower than the medieval warm period?"

    It isn't.  See chart above.

  • Most of the last 10,000 years were warmer

    Tom Curtis at 09:20 AM on 4 June, 2016

    Mike Hillis @63, point by point:

    1)  The quote by Monckton at the head of the article is simply an example of the myth being propogated.  It is not, as you suggest, part of an evidentiary chain other than to the point that the myth exists, and is propogated by at least some climate change deniers.  What is more, by claiming that it is a fabrication that "the "myth" ... is based on a comment made by Monkton", you imply that Monckton has been misquoted.  Following the link for the quote and scrolling down to the second box on page three proves that to not be the case.  Monckton was not misquoted.  He has used the myth.  But the article made no claim that Monckton is the only denier to use the myth, or that he was the primary person to propogate the myth, contrary to your suggestion.

    Monckton also explicitly ties his opinion to the GISP 2 record in another document (PDF) where he produces this graph:

    He captions it, "Warmer than today: most of the period since the end of the last Ice Age has been
    warmer than the present by several degrees Celsius" and writes:

    "Seen in the geological perspective of the last 17,000 years, the 300 years of recent warming, nearly all of which must have been natural, for we could not have had any significant influence except in the past 25 years, are manifestly insignificant."

    The comment about the 300 years shows clearly that he is treating the terminal period of the graph, which actually ends in 1855, as ending in approximately 1995.

    As a side note, he (not unusually) mislabels the source of the data, which is Cuffey and Clow (1997).

    2)  You also dispute that Monckton got the idea from Easterbrook, but Easterbrook propogated the idea in 2008 (PDF), where he produced this graph the below graph, saying:

    "The global warming experienced during the past century pales into insignificance when compared to the magnitude of at least ten sudden, profound climate reversals over the past 15,000 years (Figure 5)"


    Again, the graph is claimed to depict "global warming during the past century" even though the last data point on the graph in fact occurs in 1855.

    Easterbrook even predates Monckton on the "some 9,100 of the past 10,500 years were warmer" meme, with an article on WUWT in December, 2010 claiming that:

    "So where do the 1934/1998/2010 warm years rank in the long-term list of warm years? Of the past 10,500 years, 9,100 were warmer than 1934/1998/2010. Thus, regardless of which year ( 1934, 1998, or 2010) turns out to be the warmest of the past century, that year will rank number 9,099 in the long-term list."

    As a side note, I am puzzled as to how he determines that ranking.  Using the GISP 2 temperature data cached by Alley, from 8,905 to 8,915 of the 10,500 years BP in that record are warmer than the terminal data point.  For Easterbrook to gain his ranking, he must conclude that 2010 was significantly cooler than the year he considered to be 1905.

    As a further side note, the 2010 article by Easterbrook is the one discusses by Gareth Renowden above.

    3)  No claim is made in the OP that Easterbrook came to his conclusion as the result of just one study.  The claim that he did so is false, but the only fabrication involved is your attribution of that claim to the OP.

    4)  You claim it is absurd that Easterbrook, as a geologist, did not know that Before Present refers to before 1950 unless otherwise specified, but in the 2010 article, his reproduction of the Alley data clearly labels the x axis "Years before present (2000 AD)", thereby indicating that he took "present" in this data to refer to 2000, not 1950.  So far as I am aware, he still does so.

    5)  Regardless of his reasons, the paper trail clearly shows Easterbrook labeling the data that terminated in 1855 as "present global warming" thereby indicating the tail of that graph to be the warming during the 20th century (see graph above).  Later he clearly labelled that data on an axis for years BP, glossed as being 2000 with a final data point at 95 years BP, ie, 1905 according to his axis.

    To summarize, the purported fabrications are easilly proved to be true from the paper trail, except for two cases where the "fabrication" consists entirely in your misrepresenting the OP.

    Your record on "the facts" is equally poor.  It is true that, but entirely irrelevant, that the Holocene was labelled long before Easterbrook was born.  The studies of Holocene temperatures that lead to the "spaghetti graphs", however, are all recent (last thirty years or so), and the spaghetti graph you used does not come from a peer reviewed paper, and was originally produced in 2005.  Easterbrook has in fact used that graph, as you would know if you followed the links to the original version of the article, and back to prior history.  However, he first used the current version of the graph (produced on the 19th of July, 2010, less than a week before he used it, but only after considerable editing to make it look like this:

    Compared to the original, you will note that he has removed the "spaghetti".  More importantly, he has also removed the indication of the 2004 temperature, the inset showing recent proxies, together with the rapidly rising instrumental record.  That is, he has removed any indication that modern temperatures are in fact higher than those shown.  He does not note that the zero point on the axis is "mid 20th century average temperature", but instead inserts a line approximately 0.3 C below the mid 20th century average which he deceptively labels "Present day temperature".  In all, his treatment of this graph is much worse than his treatment of the Alley 2000 data, and cannot be construed as anything other than a deliberate attempt to deceive his audience.

    It is, however, extraordinarily unlikely that Easterbrook, who obtained his graduate degree in 1958, saw any spaghetti graph of Holocene temperatures in highschool (none having existed back then).

    Finally, the graph you cite clearly shows even mid 20th century temperatures to have been warmer than the bulk of the Holocene, while late 20th century temperatures were warmer than the multidecadal average over the entire Holocene.

    In short, your "facts" are fictions.  In some cases ridiculous fictions you invented without basis.  In others, fictions you invented in direct contradiction to known evidence - indeed, evidence presented in the OP in one case.  Skeptical Science is not a form where you are permited to just spin tissues of fabrication.  You are expected to support your claims with facts, something you have signally failed to do at any point in this discussion.  It is also hoped (though not required) that you change your views if fae moderators take a dim view of any further unsupported claims, or gish gallops by you.

  • Republicans' favorite climate chart has some serious problems

    Tom Curtis at 16:15 PM on 22 February, 2016

    FrankShann @various, CMIP5 uses historical data to 2005 inclusive, but scenario data thereafter.  The equivalent model experiments for the IPCC TAR and AR4 used historical data to 2000, and scenario data thereafter.  I am not aware of the dates for the FAR and SAR, but clearly they predated the reports themselves (1990 and 1995 respectively).  Hansen 88 used historical data only up to 1983 (from memory).

    This is important because Dana wrote:

    "Climate models are certainly useful, and are doing a pretty darn good job predicting global warming. Their predictions have been far more accurate than those made by climate contrarians, who keep telling us that the Earth will start to cool any day now, as we keep breaking heat records."

    In doing so he links to an article discussing the predictions of all five IPCC reports, plus other 'warmist' predictions, along with those few predictions made by AGW 'skeptics'.  He was not referring to just CMIP5 predictions as you suppose, and all of the predictions include several years after the last historical forcing data, including CMIP5.

    The article summarizes some of the results from a number of articles discussing the predictions of just one individual or organization in any article.  The results of the comparisons are summarized in this graph:


    So, leaving aside all the technical points about predictions and retrodictions, and predictions and projections; your criticism of Dana is wrong.  The worst that can be said of his claim is that it is fleshed out in this article, but another.  That, however, is a necessity of communication.  Even in the world of the internet, there is still no royal path to knowledge.  And links are not just decorations.

    And for what it is worth, the HadCRUT4 trend since 2005 is 0.127 +/- 0.22 C/decade, compared to a CMIP5 prediction of about 0.2 C/decade.  As the difference between scenarios is inconsequential over that time period, the distinction between projection and prediction is nugatory.  Ergo, the CMIP5 prediction still fairs fairly well, and certainly outperforms any 'skeptical' prediction over the same period.

  • What you need to know about the NOAA global warming faux pause paper

    Tom Curtis at 15:35 PM on 9 June, 2015

    BC @11, one of the features of satellite (and radiosonde) data is that it responds far more strongly to ENSO effects.  It also responds more strongly to volcanic effects, and may also respond more strongly to other short term fluctuations but I have no data on that.  The upshot is that satellite and radiosonde data is far more noisy, resulting in a greater standard deviation of the data.  That in turn requires a larger underlying trend for it to be considered statistically significant over short periods, or (alternatively put), for given trend, it requires a longer period of data before it is statistically significant.  Given that the denier test for "no warming" is "the trend is not statistically significant from zero" regardless of whether it is statistically significant from IPCC projected warming, it becomes almost a gimme for satelite data to show "no warming" in the deceitful terminology of deniers.

    All that is basic.  Less frequently commented on is something very interesting that has been happening with the Southern Oscillation Index (SOI).  The SOI measures the pressure difference between Darwin and Tahitti.  Because winds flow with pressure differences, that makes it a good proxy of the strength of the Walker Circulation, which drives the El Nino Southern Oscillation (ENSO).  Essentially, if the pressure is greater in Tahitti than in Darwin, the Walker circulation blows surface Pacific waters towards the Pacific Warm Pool in waters near Indonesia.  If they are only slightly stronger, the Walker Circulation is weak and you have normal conditions.  If the pressure in Tahiti is much greater, you have an unusually strong Walker Circulation and a strongly positive SOI, and a La Nina results.  In contrast, if the pressure falls in Tahiti relative to Darwin, the Walker circulation stops and you have strongly negative SOI values, along with an El Nino.

    The interesting thing that is happening in the SOI is that it has been systematically increasing since the early 1990s.  Because the SOI sign is the reverse of the global temperature effect, and because the peak temperature effect is felt about six months after the peak SOI effect, I have graphed the inverted, seven month lagged SOI below.  (Seven month lagged rather than six as that allows me to include a full 2015 value.)  The result should show the sign and relative magnitude of ENSO effects on global temperature over the years since 1950:


    Another way of putting that is that if ENSO was the only factor affecting the Global Mean Surface Temperature (GMST), a scaled version of the above graph would show the actual fluctuations in GMST.

    Obviously ENSO is not the only thing effecting GMST.  For instance, in 1982 the El Chichon volcanoe erupted in Mexico, the effect of which reduced 1983 to an average year rather than the warmest on record (to that time).  Likewise the Pinatubo eruption in 1992 cooled what was otherwise going to be a very warm year in 1992.  Pinatubo's effect had largely dissipated by 1995, however, which had the 13th strongest ENSO warming effect since 1877, and the 4th warmest in the satellite era.  Notably, every year in the 21st century has had a lower ENSO warming than 1995, and there is a consistent downward trend in that warming from 1998.

    Absent global warming and volcanic effects, the various years in the satellite era would have ranked as follows for warmth:

    Year SOI rank (inverted)
    1979 21
    1980 13
    1981 15
    1982 26
    1983 1
    1984 22
    1985 24
    1986 17
    1987 7
    1988 11
    1989 35
    1990 20
    1991 12
    1992 3
    1993 8
    1994 5
    1995 4
    1996 25
    1997 23
    1998 2
    1999 34
    2000 32
    2001 29
    2002 16
    2003 9
    2004 18
    2005 6
    2006 27
    2007 10
    2008 31
    2009 33
    2010 14
    2011 36
    2012 30
    2013 19
    2014 28

    You will notice that 2014 (a tied record year in GMST) would have only ranked 28th absent the effect of global warming and volcanoes.  2010 ranked 14th on ENSO warming, and just four years earlier, was also a statistical tie with 2014.  Both years were warmer than the denier poster year, 1998 (ranked 2nd on ENSO effect, or first if we include volcanic effects as well).

    Finally, the point of all this is that satellite record are (as stated at the beginning) far more effected by ENSO warming than are the surface records.  Because of the radical difference between actual warmth as measured by GMST and ENSO only rankings, we therefore expect a significant disparity in ranking between surface and satellite records.  In particular, early strong El Nino years will rank far higher relative to the later weak El Nino's that have been breaking records due to global warming. 

  • Global warming made 2014 a record hot year – in animated graphics

    Tom Curtis at 08:13 AM on 29 January, 2015

    ryland @various, my argument is not with the Met Office.  It is with the pseudo-skeptics who created a furror when (according to them) GISS announced that 2014 was a record year without qualification.  The simple fact is that 2014 is the record year in the GISSTEMP temperature index.  As it happens, the GISS announcement actually discussed the uncertainty in greater detail than has the HadCRUT4 announcement.  They just did not use the form of words that the pseudoskeptics wanted.  What is worse about some pseudoskeptics is that when knowledge of the table shown @36 became available, they treated it as a subsequent announcement, as a backdown, and as proof that 2014 was not the record year.  Each of those claims was false, and the first two grossly misrepresent the communications from NASA GISS.

    Beyond the political agenda of those pseudoskeptics, what is going on here is that people are confused by what is meant by "record x".  The record x, for whatever x is, is simply the highest value in the record.  The Guiness Book of Records, for example, does not claim that the car that currently holds the land speed record was the fastest ever car.  It simply claims that it is has the fastest speed entered in the records.  Other cars may have been faster, but been excluded because of the presence of a strong tail wind, the failure to run the test in both directions within a given time limit, or the simple absence of an official observer.  They do not even take note of potential error margins in observations which are certainly there, although I do not claim they are significant.  Likewise when reporting on the fastest delivery in cricket, nobody worries about the uncertainties in measurement.  Indeed, when record cold winters for the US are announced, the pseudoskeptics definitely do not draw attention to uncertainties (which are even more of a factor).  They just accept face value, or distort the figures.

    So, 2014 is the warmest year in the GISS record, and the warmest year in the HadCRUT4 record, and the warmest year in the NOAA record, and the warmest year in the BEST record.  That does not mean it was in fact warmer than 2010, because the measurement of GMST is uncertain - but it is the record year for each of those temperature indices.

    Further, distracting from that fact by saying it may not have been the record year is pure obfustication.  With HadCRUT4 (having now actually run the numbers), if you allow that obfustication there have been just 3 record years (1850 (by definition), 1990, and 1998), rather than the 15 record years that have actually occurred - 9 of them since 1983 (inclusive); and 4 of them since 1998 (inclusive).  (Full list at end of post.)  Further, the obfustication means that, if we accept the distorted terminology, the most recent "record year" is 1998, even though 1998 has a very low probability of being the actual hottest year in the last 150 years according to HadCRUT4, (and is "statistically excluded" according to BEST).




  • CO2 lags temperature

    Tom Curtis at 16:25 PM on 19 December, 2014

    davytw @447, you have three excellent responses so far.  Let me add that it is often worthwhile taking denier cherry picks or other selective data at face value.  If you do in this case, for example, you see that the lag shown is about 1 year.  So, assume CO2 lags temperature by one year, and assume also, as per denier dogma, that there has been a pause in global temperatures.  It follows that from one year after the pause started (1995 and 1998 seem to be the preffered values) there has been a pause in the rise of global CO2 concentrations.  If your interlocuter cannot show you that pause the raw CO2 data, then it follows that either:

    There has been no pause in global temperatures; or

    CO2 does not simply lag global temperatures and the graph has been deceptively constructed to show an appearance that is not real; or both.

    In other words, even at face value combined with the raw data, the claim refutes itself.

    On a more subtle point, the partition of CO2 between the three main surface reservoirs (atmosphere, ocean and terrestial biosphere) is governed by temperature.  In particular, increased temperatures will shift CO2 from the ocean to the atmosphere.  If there are no other relevant factors, this is the primary short and medium term controller of CO2 concentration, and given the size of the effect relative to the increase in global temperature, dominates CO2 concentrations at sub decadal time scales.  However, anthropogenic emissions over a decade or more far exceed the variation in CO2 concentration caused by small temperature effects so that anthropogenic emissions control almost completely the long term rise.

    Long term temperture trends (such as occur at the start and end of glacials) can result in long term changes in CO2 concentration.  However, taking the graph your denier interlocuter provided, the ratio appears to be 1 ppmv of CO2 increase for every 2.5 C increase in temperature.  (Again the advantage of face value.  Your interlocuter must either admit that figure or something very close, or admit the graph has been deceptively constructed.)  Based on that figure, the approximate 1 C temperture increase since the preindustrial can only be responsible for about 0.5 ppmv increase on CO2 concentration ;)

    Of course that figure is way to low, because the graph is deceptively constructed.  Using the ratio between temperature and CO2 concentrations in the glacial, the actual increase in CO2 due to the 1 C increase in temperature may be as much as 20 ppmv.  Of course, that increase is itself no more natural than the warming.

  • Athabasca Glacier: a tragic vanishing act

    Tom Curtis at 04:03 AM on 28 August, 2014

    sotolith7 @14, the original research you seem to be relying on is Hormes et al (2001) and Joerin et al (2006).  What in fact happened to the theory (to answer MA Rodger's question) was Schnedejoch, and more particularly the discussion of the Schnidejoch finds by Grosjean et al (2007).  Specifically, Grosjean et al show the continuous presence of ice in the Schnidejoch Pass (based on the argument I presented above).  They discuss the apparent discrepancy with Hormes et al and Joerin et al, saying:

    "At first glance our conclusion differs from the conclusions drawn from exposed trees in the forefields of melting glacier tongues (Jo¨rin et al., 2006). However, the conclusions by Jo¨rin et al. (2006; see also by Hormes et al., 2006) refer to the AD 1985 level:‘glaciers in the Grimsel [and Alpine] area were smaller than at 1985 AD during several times for the last 5000 years’; while our conclusion reads: ‘in the year of 2003 AD, the ice field at Schnidejoch has reached the smallest extent since the last 5000 years’.

    This is not a contradiction. We argue that this difference is explained by the dissimilar response lags of the two types of archives compared: ice mass balance near the LA (Schnidejoch) responds immediately to sub-decadal climate variations, while Alpine glacier tongues respond with a multi-decadal lag to climatology (20–60 years (Jo¨rin et al., 2006); importantly this fact also applies to the study by Hormes et al. (2006)). Differences between the equilibrium states of fast and slowly responding climate archives are typically large during phases of rapid changes. Indeed while the ice field at Schnidejoch is in equilibrium with the state of the atmosphere of the most recent years, the glacier tongues have not yet fully responded to the excessively warm years of the last 15 years, when (1) solar radiation at the Earth’s surface has increased owing to brightening of the atmosphere (globally 6.6 W m-2 10 yr-1 between 1992 and 2002, Swiss Plateau 7.2 W m-2 10 yr-1; Wild et al., 2005), (2) anthropogenic greenhouse forcing with related strong water vapour feedback enhanced the downward longwave radiation in Europe (+1.18 W m-2 yr-1, data 1995–2002; Philipona et al., 2005) which increased temperatures, and (3) negative trends in the specific mass balance of Alpine glaciers accelerated (Zemp, 2006)."

    In short, the discrepancy is explained because (1) the two results use different reference years and there as been a large change in atmospheric forcing and temperature between those two years, and (2) glaciers respond slowly to changing conditions so that the current glacial extents (let alone those of 1985) are not in equilibrium and will retreat quite a bit further before they are.

    It should be noted that the finds in Schnidejoch do not directly contradict the results of Hormes et al or Joerin et al in that different microclimates in different alpine valley are known to result in slightly different responses to temperature changes at different times.  Note that Schnidejoch responded rapidly to warmth in recent times, and the potential of decay precludes decades long exposures of the artifacts found in the pass.  That therefore precludes glacial retreats in the past 5000 years greater than the current equilibrium state of Alpine glaciers (although greater than the current retreat due to slow response times).

    Finally, Grosjean is not a complete answer to Hormes and Joerin in that they also show a higher altitude treeline.  Treelines, of course, also respond slowly to changes in temperature.  Nicolussi et al (2005) estimate early 2000 treeline levels to reflect climate conditions in the 1980s.  Since the 1980s, climate change has resulted in a 1 degree C increase in temperatures at the alpine treeline since the 1980s, with a projected further rise of the treeline by 200 meters as the result (Gehrig-Fasel et al, 2007) .   Returning to Nicolussi et al, they find:

    "In the space of the last 4000 years the dendrochronological tree-line record is not continuous, probably due to human impact. Tree-line positions similar to or slightly above the 1980 tree-line are established for the time periods approx. 1000 to 640 b.c. and a.d. 1 to 330 respectively. For the time period between approx. 7100 and 2100 b.c. the dendrochronologically analysed logs show nearly continuous evidence of a tree-line above the 1980s limit. Very high elevation of the tree-line, between 120 and 165 m above the 1980s level (2245 m a.s.l.) and even higher than the a.d. 2000 tree-species-line (2370 m a.s.l.), are recorded for the periods 7090–6570, 6040–5850, 5720–5620, 5500–4370 b.c., approx. 3510–3350 b.c. and 2790–2590 b.c. Additionally, a tree-line which was located at least 50 m above the 1980s limit can be shown for the periods 6700–5430, 4920–3350 and 3280–2110 b.c. The dendrochronological record from the Kauner valley, showing high and very high tree-line positions between approx. 7100 and 2100 b.c. with only two gaps (around 6490 b.c. and from 3350 to 3280 b.c.), suggests that summer temperatures as observed in the late 20th century were at the normal or the lower limit of the temperature range which can be assumed for long periods of the early and middle Holocene epoch."

    So, treelines above the 1980s level were found 4000 years ago, or older, with two small episodes of treelines matching the 1980s level after that.  No trees were found as high as the projected stable treeline for current alpine temperatures (with the highest, being from the early holocene, and about 30-40 meters below that level).

    Consequently, the Hormes and Joerin results are accurate, but consistent with early 2000 temperatures exceding stable alpine temperatures at any time in the Holocene.  Of course, those temperatures have been only been occuring for a decade, and decadal temperature fluctuaions above that in the early to mid holocene, and specifically prior to the earliest remains from Schnidejoch are quite likely.  Those elevated NH temperatures, however, are a direct consequence of the milankovitch cycles that lead to much higher NH summer insolation at that time.  Further, soon anthropogenic warming will take alpine temperatures above even those early holocene peaks - indeed much above them.

  • 2014 Arctic Sea Ice Extent Prediction

    billthefrog at 03:27 AM on 23 August, 2014

    @ Gavin,

    Absolutely no need for a mea culpa. I've been looking at the SEARCH (and now SIPN) stuff for about 5 years, and for the first 12-18 months I thought the same as you - and for exactly the same reason. It was only as I became more familiar with the data, that I realised it had to be the monthly mean which was being used. Largely as a consequence of this confusion, I've tried to drill myself to always explicitly state the time period of a min (or max). 

    I totally agree with your comments regarding the fact that, whatever the confidence interval selected, there is a gradual transition in the "confidence" of the result. A classic example of this being twisted to nefarious purpose was the loaded question that Phil Jones was presented with in 2010. The case was eloquently described by Dana on the SkS site, with the crux of the matter being the following question and answer...

    Q: "Do you agree that from 1995 to the present there has been no statistically-significant global warming?"

    A: "Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."

    When I tried to work out the actual confidence level using the HadCRUT3 dataset, I think it came out at around 93% or 94%, but that's not how it was reported by the usual suspects.

    For what it's worth, I tend to omit outliers such as 2007 (and latterly 2012) when trying to "outguess" the Arctic. This strategy wasn't bad in 2010 and 2011, but failed spectacularly in 2012, 2013 and 2014. (No prizes for guessing in which direction I was wrong about each of those years.)

    Cheers   Bill F

  • 2014 SkS Weekly News Roundup #13A

    Poster at 08:56 AM on 28 March, 2014

    I think the comment is that there has been no statistically significant increase in global warming since 1998 (actually I think some say since 1997 and others claim since 1995)

  • It hasn't warmed since 1998

    DSL at 23:42 PM on 12 September, 2013

    MrGibbage, by what measure?  Ocean heat content shows no "hiatus" over the period, and it makes up 90%+ of the effective thermal capacity of the climate system.  Global ice mass loss makes up another 2-3%, and it has accelerated over the surface "hiatus" period.  Further, if you run a 30-year linear from 1975 to 1998, you get 0.163C per decade, and that doesn't factor in the lower transient response of the period's earlier years.  If you run 1975 to 2008, you get 0.19C per decade.  So when did the "hiatus" begin?  

    Further, could Fyfe not have written this in 1995?  The trend from 1981 to 1995 is 0.0879C per decade.  The trend for 1997 (capturing the full 97/8 El Nino) to present is 0.071C.  Not far apart.  The trend from 1981 to present is 0.161C per decade.

    All Fyfe is saying, to me, is "models are sketchy at projecting short-term surface temp fluctuations," which, of course, everyone already knows.  

    Now, has global warming "paused"?  Or has the surface temp trend "paused"?  Slow day at the Fyfe office, especially since five bajillion people have already covered the issue.  Have you read Kosaka & Xie 2013?  Does HockeySchtick provide fair and balanced coverage of it?

  • CO2 effect is saturated

    basnappl at 15:00 PM on 7 July, 2013

    Hello Tom,

    Thanks for the reply.  I read through the preprint as best I could.  I am unfamiliar with the models used and some of the terminology.  Is it true that, in their analysis, the temperature profile of the atmosphere is the fitting parameter?

    As far as how well I represented their claims, I will quote with some (perhaps unnecessary) context:

    First quote, commenting on the difference spectra figure I included in my previous post:

    "An initial inspection indicates that the processing of the data has not caused any major artifacts. In all cases the difference spectra are seen to have consistent and reproducible
    features. The only sign of asymmetry (which could indicate a mismatch of wavenumber scales between the spectra) is in the CO2 (0110 → 1000) band at 720 cm-1, which may be due to its position on the very steep high frequency wing of the CO2 fundamental centered
    at 667 cm-1."

    Second quote, in reference to the same:

    "A negative brightness temperature difference is observed in the CO2 band at 720 cm-1 in the IMG–IRIS (1997–70) and the AIRS–IRIS (2003–1970) difference spectra, indicating increasing CO2 concentrations, consistent with the Mauna Loa record (Keeling et al. 1995). However, this channel in the difference is also sensitive to temperature, and we note that in the 2003–1997 difference, despite a growth in CO2 between these years, there is no signal at 720 cm-1."

    Third quote is where the portion in my previous post comes from, now with context:

    "The CO2 band at 720 cm-1, though asymmetric for the reasons stated earlier, nevertheless shows some interesting behavior, with strong negative brightness temperature difference features for 1997–1970 and 2003–1970: whereas, the 2003–1997 (a much shorter period, of course) shows a zero signature. Since we know independently that the CO2 concentration globally continued to rise between 1997 and 2003, we must conclude that the 2003–1997 result must be due to changes in temperature that compensate for the increase in CO2. This would mean a warming of the atmosphere at those heights that are the source of the emission in the center of this band. This is somewhat contrary to the general (small) cooling of the stratosphere at tropical latitudes." (emphasis mine, I'm only trying to show where my "explanation" came from)

    Fourth quote, regarding differences between model results and observations:

    "Finally, there exists a marked gradient in the simulated spectrum between 800 and 700 cm-1, which is absent in the observations. This coincides with the far wings of the strong CO2 band centered at 667 cm-1. In sensitivity tests, this gradient showed sensitivity to the amount of CO2, and is therefore related to the strong CO2 band, and may reflect reanalysis uncertainties in temperature."

    The paper includes appendices detailing the temperature profiles used to coerce the models to the data.

    I would appreciate some help digesting this.

  • 16 years - Update and Frequently Asked Questions

    Bob Loblaw at 12:01 PM on 11 February, 2013

    What was Phil Jones up to "back in the seventies"? Not sure. The first major paper of his looking at the temperature record that I'm aware is the 1982 paper that looked at northern hemisphere record:

    Variations in Surface Air Temperatures: Part 1. Northern Hemisphere, 1881–1980

    I've linked the abstract, and the pdf link for the full paper on that page is not paywalled.

    Note that to maximize the "drop" in that record, you have to pick 1940 as the start year, just as fake skeptics keep picking 1998 these days. Spikes in the record - the gift that keeps on giving...

    Methinks that Habilus is mixing up a whole bunch of fake skeptic memes:

    - They predicted an ice age in the 1970s

    - Hansen was wrong

    - Jones said no warming

    - UK Met Office is bad (aka Climategate and the CRU hack)

    Just what were you paying attention to in the '70s, Habilus?


  • Misleading Daily Mail Article Pre-Bunked by Nuccitelli et al. (2012)

    Sapient Fridge at 19:46 PM on 31 December, 2012

    Punksta, are you now claiming that back radiation doesn't exist? Wow. Got anything to back that up?

    Here's an explanation of back radiation and details of how to see it for yourself by one of the "skeptics" favourite scientists, Roy Spencer. A more in-depth explanation is provided by The Science of Doom.

    Regarding your misunderstanding that that fact that warming has not reached statistical significance in the last 16 years means that there has been no warming in that time, have a look at the graphs in this post by Tamino. The trend from 1980 to 1997 is lower than the trend from 1997 to 2012. It just hasn't reached the point where we can say we are 95% sure that it isn't by chance.

    When we are over that 95% confidence level the deniers will simply pick a shorter period after that time. Previously the date chosen by AGW deniers was 1995, but when warming since then reached statistical significance (95% confidence) they moved the date to 1998. In a few years the meme will be that there has been no warming since 2004, or some such date.
  • It's El Niño

    Bob Tisdale at 00:49 AM on 3 December, 2012

    At comment 107, Composer99 quoted one of my earlier comments: “Are you aware that the global oceans can be divided into logical subsets which show the ocean heat content warmed naturally?”

    Composer99 replied, “No, they can't. Ocean heat has to come from somewhere.”

    Apparently you have never divided OHC data into subsets, because if you had, you would not make such a statement. Dividing the oceans into subsets shows the ocean heat comes from somewhere, but it’s not CO2.

    For the sake of discussion, I’m going to borrow some graphs from an upcoming post. Here’s a comparison graph of Global ocean heat content and the ocean heat content for the Pacific Ocean north of 24S, which captures the tropical Pacific and the extratropics of the North Pacific (24S-65N, 120E-80W). The Pacific OHC (North of 24S) shows similar but somewhat noisier warming. That is, the decadal variations are similar. The warm trend of the Pacific subset is about 72% of the global trend, but that’s to be expected since the excessive warming of the North Atlantic OHC skews the global data. All in all, both datasets give the impression of a long-term warming that’s somewhat continuous. People might assume the warmings of both datasets were caused by CO2.

    We’re going to separate the tropical Pacific (24S-24N) from the extratropical North Pacific (25N-65N), looking at the tropical Pacific first, but that requires a brief overview of how La Niña events produce the warm water that fuel El Niño events.

    El Niño and La Niña events are part of a coupled ocean-atmosphere process. Sea surface temperatures, trade winds, cloud cover, downward shortwave radiation (aka visible sunlight), ocean heat content, and subsurface ocean processes (upwelling, subsurface currents, thermocline depth, downwelling and upwelling Kelvin waves, etc.) all interact. They’re dependent on one another. During a La Nina, trade winds are stronger than normal. The stronger trade winds reduce cloud cover, which, in turn, allows more downward shortwave radiation to enter and warm the tropical Pacific.

    If you’re having trouble with my explanation because it’s so simple, refer to Pavlakis et al (2008) paper “ENSO Surface Shortwave Radiation Forcing over the Tropical Pacific.” Note the inverse relationship between downward shortwave radiation and the sea surface temperature anomalies of the NINO3.4 region in their Figure 6. During El Niño events, warm water from the surface and below the surface of the West Pacific Warm Pool slosh east, so the sea surface temperatures of the NINO3.4 region warm, causing more evaporation and more clouds, which reduce downward shortwave radiation. During La Niña events, stronger trade winds cause more upwelling of cool water from below the surface of the eastern equatorial Pacific, so sea surface temperature to drop in the NINO3.4 region, in turn causing less evaporation. The stronger trade winds also push cloud cover farther to the west than normal. As a result of the reduced cloud cover, more downward shortwave radiation is allowed to enter and warm the tropical Pacific during La Niña events.

    To complement that, here’s a graph to show the interrelationship between the sea surface temperature anomalies of the NINO3.4 region and cloud cover for the regions presented by Pavlakis et al.

    That discussion explains why the long-term warming of the Ocean Heat Content for the tropical Pacific was caused by the 3-year La Nina events and the unusual 1995/96 La Niña. First, here’s a graph of tropical Pacific Ocean Heat Content. It’s color coded to isolate the data between and after the 3-year La Niña events of 1954-57, 1973-76 and 1998-2001. Those La Niña events are shown in red. Note how the ocean heat content there cools between the 3-year La Niña events. Anyone who understands ENSO would easily comprehend how and why that happens. It’s tough to claim that greenhouse gases have caused the warming of the tropical Pacific when the tropical Pacific cools for multidecadal periods between the 3-year La Niñas, Composer99.

    As you can see, the warming that took place during the 1995/96 La Niña was freakish. Refer to McPhaden 1999 Genesis and Evolution of the 1997-98 El Niño”.

    McPhaden writes:

    For at least a year before the onset of the 1997–98 El Niño, there was a buildup of heat content in the western equatorial Pacific due to stronger than normal trade winds associated with a weak La Niña in 1995–96.

    Based on the earlier description, that “build up of heat content” resulted from the interdependence of trade winds, cloud cover, downward shortwave radiation and ocean heat content. Simple. As you can see in the above graph, the upward spike caused by the 1995/96 La Niña skews the trend of the mid-cooling period, and if we eliminate the data associated with it and the 1997/98 El Niño, then the trend line for the mid-period falls into line with the others.

    So far, there’s no apparent AGW signal.

    Let’s move on to the extratropical North Pacific. That dataset cooled significantly from 1955 to 1988, more than 3 decades. Where’s the CO2 warming signal there, Composer99? Then in 1989 and 1990, there was an upward shift. It’s really tough to miss, because the North Pacific was cooling before the sudden 2-year warming and then it warmed after it. As you’ll note, the cooling trend before the shift is comparable to the warming trend after it. BUT, big but, the cooling period lasted for 34 years, while the warming period only lasted for 22 years. That means the North Pacific (north of 24N) would have cooled since 1955 if it wasn’t for that 2-year upward shift.

    In summary, the ocean heat content data for the Pacific Ocean north of 24s (the initial graph)  gives misleading impression of a relatively continuous warming; it’s misleading because, when the data is broken down into two logical subsets, tropics versus extratropics of the North Pacific, the data clearly shows that factors other than greenhouse gases were responsible for the warming.

  • It's El Niño

    Bob Tisdale at 00:26 AM on 3 December, 2012

    KR says at 124: “If as you say La Nina's absorb more heat (due perhaps to changes in cloudiness or other effects) than El Nino releases, how can this have driven warming since the 1970's? There has been a preponderance of El Nino events over that period (fewer than average La Nina events to raise total climate energy, esp. late 1970's-1998).”

    You need to look at surface temperature and ocean heat content separately, because they respond differently to ENSO.

    Let’s discuss surface temperatures first:

    KR, we agree on something. “There has been a preponderance of El Niño events over that period…” Glad you confirmed that ENSO has been skewed toward El Niño since the late 1970s. This means that more warm water than normal has been released from the tropical Pacific and redistributed, and it means that more heat than normal has been released to the atmosphere. That answers your question, “how can this have driven warming since the 1970's?”

    Now let’s address the ocean heat content portion of your question: “If as you say La Nina's absorb more heat (due perhaps to changes in cloudiness or other effects) than El Nino releases…”

    This makes itself known in the Ocean Heat Content for the tropical Pacific. The 1973-76 La Niña created the warm water that served as the initial fuel for the subsequent 1982/83 through the 1994/95 El Niño events, with the La Niña events that trailed those El Ninos replacing part of the warm water. That’s why the tropical Pacific OHC trend is negative from 1976 until the 1995/96 La Niña.

    The 1995/96 La Niña was a freak, and discussed in McPhaden 1999. “Genesis and Evolution of the 1997-98 El Niño”.

    McPhaden writes:

    For at least a year before the onset of the 1997–98 El Niño, there was a buildup of heat content in the western equatorial Pacific due to stronger than normal trade winds associated with a weak La Niña in 1995–96.

    In other words, there are parts of ENSO that cannot be accounted for with an ENSO index.

    The impact of the 1995/96 La Niña stands out like a sore thumb in the graph of tropical Pacific OHC. Then, moving forward in time, there’s the dip and rebound associated with the 1997/98 El Niño and 1998-01 La Niña.

    KR asks: “Why now? What has changed? The ENSO has been an existent pattern for perhaps hundreds of thousands of years. Why would it suddenly change behavior in recent years, when it hasn't in the past?”

    Paleoclimatological studies find evidence of ENSO back millions of years ago—not just hundreds of thousands of years. See Watanabe et al (2011). Your second question (“Why would it suddenly change behavior in recent years, when it hasn't in the past?”) is an assumption on your part. El Niño events were also dominant during the early warming period of the 20th Century, and global temperatures warmed in response then, too.

    KR asks: “Finally, what about the greenhouse effect?”

    Downward longwave radiation appears to do nothing more cause a little more evaporation from the ocean surface, which makes perfect sense since it only penetrates the top few millimeters.

  • Mars is warming

    Tom Curtis at 09:10 AM on 26 May, 2012

    Well, let's look at the photos, or images at least:

    Mars, 1873:

    Mars, 2007:

    So from 1873 to 2007, Mar's NH polar cap has approximately the same size, while its SH polar cap has greatly expanded.

    But what about images like this:

    According to AGW denier, Nasif Nahle, this is a ...

    "Sequence of photos illustrating the Global Warming on Mars. Observe how Mars' Polar Caps have been melting since 1990, the same phenomenon has been occurring on Earth."

    Except, when I look at the pictures, I see the large expansion of the SH polar cap from 1995-2001, followed by its contraction. I also see the initial contraction of the NH polar cap, followed by its expansion, after which it is hard to say what it does because it is hidden behind the limb of the planet.

    Clearly, the polar caps of Mars are very dynamic. The rapidity with which they change their extent can be seen in this montage showing the NH cap over a period of six months:

    As we know, by 2001,it had already regained its lost extent, and no doubt lost it again before regaining it in 2007.

    AGW deniers, like Nahle, are attempting to portray images of seasonal variation as proof of global warming on Mars. But if you look at all the evidence, its easy to see through their parlour trick.
  • IPCC graph showing accelerating trends is misleading

    Tom Curtis at 09:48 AM on 15 May, 2012

    SRJ @86, the question under discussion here is not, "What is the best method to analyze temperature trends over the last 150 years?" The IPCC's analysis did not consist of just the illustration under discussion, which as Dikran Marsupial has pointed out, only appears in summaries of the data, not in direct analyses of the data.

    In FAQ 3.1 where a similar figure to that above appears, the IPCC says:

    "Expressed as a global average, surface temperatures have increased by about 0.74°C over the past hundred years (between 1906 and 2005; see Figure 1). However, the warming has been neither steady nor the same in different seasons or in different locations. There was not much overall change from 1850 to about 1915, aside from ups and downs associated with natural variability but which may have also partly arisen from poor sampling. An increase (0.35°C) occurred in the global average temperature from the 1910s to the 1940s, followed by a slight cooling (0.1°C), and then a rapid warming (0.55°C) up to the end of 2006 (Figure 1). The warmest years of the series are 1998 and 2005 (which are statistically indistinguishable), and 11 of the 12 warmest years have occurred in the last 12 years (1995 to 2006). Warming, particularly since the 1970s, has generally been greater over land than over the oceans. Seasonally, warming has been slightly greater in the winter hemisphere. Additional warming occurs in cities and urban areas (often referred to as the urban heat island effect), but is confined in spatial extent, and its effects are allowed for both by excluding as many of the affected sites as possible from the global temperature data and by increasing the error range (the light grey band in the figure)."

    Clearly, therefore, the IPCC makes people aware of the high trends in Global Mean Surface Temperature (GMST) in the middle of the 20th century. These high trends correlate with high trends in total Top of Atmosphere (TOA) forcing, although the forcings do not completely explain it. Because of that correlation, it would be an embarrassment to the IPCC if there where not high trends in GMST in the middle of the 20th century.

    As the IPCC makes people aware of the mid 20th century trends, their purpose in the diagram we are discussing is not to conceal them. Rather, it is to illustrate the general tendency to higher trends as the century progresses. If that illustration is not to be misleading, then an inductive inference from the pattern shown to the acceleration of the warming over the period in question must be justified. That is what has been questioned by Monckton and by Helena.

    So, while I agree that the additive model is better than the IPCC's chart, that is not relevant to this discussion. Further, while I agree that for most purposes comparing trends of different length is unwise, that is also not relevant to this discussion. What is relevant is the question as to whether or not, if you do compare trends as the IPCC has done, you can validly make an inductive inference that the warming has accelerated.

    Please note that simply comparing the peak 25 year trend in different periods does not answer that question. Consequently, for this purpose your first chart is worse than the IPCC's. That is because a high trend ending in a particular year may be followed by a low trend shortly thereafter. Consquently you can have more total warming with a lower peak trend which is reached year after year than with a higher peak trend that is reached and simply falls away. Another way of putting that is that that you get greater warming with more robust trends, and hence it is the robust trends which better indicate increased warming.

    Finally, the attack on the chart above by Monckton is not based on statistical qualms. Rather it is based on a desire to attack the IPCC to undermine action on global warming. You can be sure that had the IPCC used the additive model shown by you, it would have come under equally virulent, and unwarranted assault. If you do not believe this, just consider the continuing unjustified assaults against the validity of the temperature record itself.
  • Global Surface Warming Since 1995

    Slioch at 17:19 PM on 23 April, 2012

    #8 KR, #9 Sphaerica and #10 dana1981
    Thanks for responding, and I'm sorry to be a little late getting back to you - I've been away for much of the last few days.
    Having looked at the matter again, I must say, yes, you are right: I had misinterpreted the Jones 1995 statement and he was merely concerned with the question of whether or not there had been warming since then.
    I still find the Santer paper somewhat ambiguous from the quote given above, since he refers to "identifying human effects on global-mean tropospheric temperature" rather than simply to "warming".
    As for Forster and Rahmstorf 2011, they show that when ENSO, solar and volcanic influences are removed from the temperature series there is still a warming trend. I cannot see how interpreting that by saying that the remaining warming trend cannot be attributed to ENSO, solar and volcanic influences is incorrect, though my final sentence in #7 went too far.
  • Global Surface Warming Since 1995

    Slioch at 18:05 PM on 20 April, 2012

    #4 dana1981
    "the question here is whether it's warming, not the causes of that warming."

    Hmmm, no I don't think that is correct, but would welcome views on this issue.

    There are two questions, when examining a segment of a temperatures/time series of global surface temperatures such as HADCRUT or GISS (or lower troposphere UAH or RSS).

    The first is whether, taking into account the errors in the measurements, one is justified in saying that there has been a warming trend in the data over a particular period. For example, any period of a few years leading up to the great El Nino of 1998 would show warming, and that warming would be statistically significant in the terms that you have used: ie even taking into account the errors of measurement, a statistical analysis of the segment of a few years running up to 1998 would surely (say I, not having done the analysis!) conclude that there is a greater than 95% probability that warming, however caused, was occurring during that segment. Is that not the case?

    The second is whether any such warming is human induced.

    It seems to me that the sense in which you are interpreting the term 'statistical significance' is in answer to the first question, but that is not the issue, as far as I understand it it, that Santer was addressing. He was making a similar statement to that of Phil Jones in his famous BBC interview in February 2010, here:

    BBC - "Do you agree that from 1995 to the present there has been no statistically-significant global warming"

    Phil Jones "Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."

    As far as I understand it, Santer and Jones were addressing the issue of whether the observed warming was due to human actions or not. After all, that is the interesting question, that is what people want to know: would the observed warming have occurred anyway, in the absence of human influences? Or can we state that there is a 95% probability that the warming is due to human actions and would not have occurred naturally? This the issue that Jones addresses explicitly later in the interview:

    BBC "How confident are you that warming has taken place and that humans are mainly responsible?"

    Phil Jones "I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity."

    That is also the issue that Foster and Rahmstorf (2011) address: if the main natural factors influencing surface or lower troposphere temperatures (solar, ENSO and volcanic) are (more or less) removed from the temperature series, is there a remaining warming trend that can be attributed to human influence? That is the question that they elegantly answer in the affirmative. They were not addressing the question of whether there had been any warming at all, but the causes of it.
  • Yes Happer and Spencer, Global Warming Continues

    Same Ordinary Fool at 14:00 PM on 4 April, 2012

    Here's another way of looking at some of the golden oldies in Happer's blogpost editorial...explicitly in terms of SkS's Skeptic Arguments.

    The Fixed Numbers numbering system in the Argument drop down box, is used because it is permanent. The other lists are in order of popularity, so their numbering will change over time. Fixed Numbers

    "Par" is the number of Happer's paragraph, followed by its first two words.
    Next comes a brief summary of Happer's statement.
    Followed by the Fixed Number, and the shortie description of the Skeptic Argument.

    Par 2 What is...
    For 10 years...........Fx7-1998

    Par 3 The lack...
    Statistical significance..........Fx82-1995

    Par 4 CO2 is...
    CO2 not a pollutant..........Fx42-pollutant
    Higher CO2 levels..........Fx45-pastco2
    Plants grow better..........Fx120-plant
    Exaggerated effects..........Fx12-impacts
    Fossil fuel countries..........Fx177-expensive

    Par 5 The direct...
    Low sensitivity..........Fx30-sensitivity
    Positive feedback..........Fx-143-clouds

    Par 6 There has...
    Early warming..........Fx1-sun
    Natural causes..........Fx35-pre1940

    Par 7 Frustrated by...
    Extreme weather..........Fx41-extreme

    Par 9 Large fluctuations...
    US cold weather..........Fx15-cold

    Par 13 It is...
    Computer models..........Fx5-model

    On its editorial pages, on the global warming issue, the Wall Street Journal plays a strange kind of favoritism towards the fossil fuel, and fossil fuel dependent, industries. While deceiving another constituency: all those who read the WSJ for long term investment advice.

    In this instance an atomic physicist writing as an authority on climate science declares that global temperatures have not increased much in the last 10 years. Yet we see from Foster and Rahmsdorf's graph in Fx7-1998 that, after removing the ENSO signal and the effects of solar and volcanic activity, that the global temperatures are actually still increasing relentlessly at the same rate as they have been since 1979.
  • The Skeptical Science temperature trend calculator

    barry at 01:05 AM on 28 March, 2012

    Kevin - thanks for a straight answer. It seems I can make use of the tool in a limited way after all. I'll keep plodding.

    It seems that one were best to avoid making bold statements on trends that border on being statistically/not statistically significant. A bit more data, a few more months in this case, can undo your assertion.

    I liked Robert Grumbine's Jan 2009 post (one of a series) on minimum periods to usefully determine global temp trends (20 - 30 years). Santer et al (17 year minimum) and Tamino (and I think Rahmstorf in a 2007/8 paper on the most recent 17-year temp trend) have indicated that less than a couple of decades is sufficient to get a statistically significant trend, but it appears that these are unfortunate suggestions to have advanced in the popular debate. At 17 years to present, NOAA, HadCRUt, RSS and UAH all fail statistical significance (using the SkS tool - I think!).

    A theme that keeps popping up for me as a reader is the problem of balancing completeness with making things accessible to a lay audience. The 17-year thing (which is now cited in the skeptiverse), and Jones' latter comment on statistical significance in the HadCRUt record being achieved, which was made into a post here, are good examples. It seems to me that the message can be pushed harder than the facts when they are oversimplifed.

    Bookmarked this page and look forward to making use of the great new gadget. Thanks be to the creators.
  • Foster and Rahmstorf Measure the Global Warming Signal

    Tom Curtis at 05:11 AM on 29 December, 2011

    DaneelOlivaw @82, I have seen ENSO cited as the cause of the warming numerous times by deniers, and infamously, McLean, De Freitas and Carter have argued that ENSO is the major cause of the warming trend in the peer reviewed literature.

    Volcanoes cannot cause global warming, but their absence can. Notably both the strong warming in the early twentieth century and the Medieval Warm Period are attributed at least in part to a relative absence of large volcanic eruptions. Indeed, F&R2011 find that the lack of large eruptions since 1995 has contributed positively to the trend on all indices, although the net contribution is small and overwhelmed by other factors.

    Finally, TSI is declining but warming has been attributed to other solar related factors. Because F&R2011 use a statistical approach rather than a physical (model based) approach, any solar effects in addition to variations in TSI are also captured by their approach, so long as those effects are significantly correlated with the solar cycle. Therefore they rebut any putative increasing non-TSI solar forcing (so long as it is correlated with TSI) as well as TSI forcing as a cause of the long term trend.

    You state that:

    "In my view what they tried to do is to, knowing that global warming is primarily anthropogenic, remove the noise produced by other factors in order to see that anthropogenic signal more clearly."

    That is my view as well. However, that does not preclude their paper from having larger implications. One such implication is that, by identifying the temperature signal associated with each "forcing" signal, ie, the MEI, AOD, and TSI they reduce the uncertainty regarding the anthropogenic contribution to the rise in temperatures. A second is that by constructing a temperature signal free of identifiable noise, they produce a clear temperature signal which can be compared with putative causes of that signal. As indicated elsewhere, that comparison refutes most major alternatives to anthropogenic forcing as a cause of the temperature increase. Neither of these points is made in the paper - but they follow from it.
  • Increase Of Extreme Events With Global Warming (Basic Version)

    muoncounter at 02:46 AM on 13 November, 2011

    Eric #17: "muoncounter's conclusion..."

    I'm flattered, but I am also hardly a reputable source.

    One of the more telling points, after considerable back and forth over which metric to use (!), was this graphic:

    -- source

    This was an attempt to analyze ACE (accum cyclonic energy), which is purely a wind speed - duration metric, by its components. In addition, there was some discussion of the fact that ACE ignores the large rainfall events like tropical depressions and gives more weight to slow-moving storms.

    So the context of 'the science isn't settled' was an argument over interpretations of fewer landfalling storms/more named storms and lower ACE/more precipitation. We can now add another datapoint/bone of contention: Of the 25 'above normal' Atlantic seasons (including 2011) shown here, 15 occurred since 1970; of the 13 'hyperactive' seasons, 8 occurred since 1995.
  • Increase Of Extreme Events With Global Warming (Basic Version)

    invicta at 03:48 AM on 12 November, 2011


    How important is getting the message across to the disinterested public. I suggest that even your clear and not technically difficult comment would leave a lot of them yawning. How scientist talk to the public must be a factor in the equation.

    If eg Dr Phil Jones had said something like
    "No, I would say that the warming trend of 0.12deg C since 1995 does not quite achieve statistical significance....."
    a great many lurid headlines might have been avoided.
    But probably going OT
  • Pielke Sr. and SkS Warming Estimates

    Tom Curtis at 01:33 AM on 12 October, 2011

    Dr Pielke @28,

    1) I recommend that you reread my post @25, or better yet, Myhre and Stordal, 1997. As clearly indicated in my post, it was Myhre et al, 1998 who determined the strength of the CO2 radiative forcing by determining the value of the constant in the simple formula for radiative forcing. In doing so they corrected downwards the factor previously used from 6.3 to 5.35.

    As explained previously, Myrhe et al is built on the detailed model comparisons in Myrhe and Stordal 97, which include a global model run at a 2.5o x 2.5o resolution. That model, because global necessarily included the difference in radiative transfer between tropical and not tropical regions. To further clarify the point, I noted that M&S97 had also run both the broadband model and the LBL model for both tropical and mid-latitude summer conditions, with the latter showing the stronger forcing, clearly showing the effect of increased humidity and cloud cover had been included.

    To that information, we can add the following quote from the Third Assessment Report:

    "IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included. The lower forcing in the cited newer studies is due to an accounting of the stratospheric temperature adjustment which was not properly taken into account in the simplified expression used in IPCC (1990) and the SAR (Myhre et al., 1998b). In Myhre et al. (1998b) and Jain et al. (2000), the short-wave forcing due to CO2 is also included, an effect not taken into account in the SAR. The short-wave effect results in a negative forcing contribution for the surface-troposphere system owing to the extra absorption due to CO2 in the stratosphere; however, this effect is relatively small compared to the total radiative forcing (< 5%)."

    (My emphasis)

    The Fourth Assessment Report contented itself with saying:

    "The simple formulae for RF of the LLGHG quoted in Ramaswamy et al. (2001) are still valid. These formulae are based on global RF calculations where clouds, stratospheric adjustment and solar absorption are included, and give an RF of +3.7 W m–2 for a doubling in the CO2 mixing ratio. (The formula used for the CO2 RF calculation in this chapter is the IPCC (1990) expression as revised in the TAR. Note that for CO2, RF increases logarithmically with mixing ratio.) Collins et al. (2006) performed a comparison of five detailed line-by-line models and 20 GCM radiation schemes. The spread of line-by-line model results were consistent with the ±10% uncertainty estimate for the LLGHG RFs adopted in Ramaswamy et al. (2001) and a similar ±10% for the 90% confidence interval is adopted here. However, it is also important to note that these relatively small uncertainties are not always achievable when incorporating the LLGHG forcings into GCMs. For example, both Collins et al. (2006) and Forster and Taylor (2006) found that GCM radiation schemes could have inaccuracies of around 20% in their total LLGHG RF (see also Sections 2.3.2 and 10.2)."

    (My emphasis)

    Ramaswamy et al, 2001 is of course, the IPCC TAR. The IPCC do not feel it necessary to spell out details that have been public knowledge for six years (as at the time of the AR4), contenting themselves with a reference to the original discussion.

    Now, given the detailed analysis by Myhre and Stordal and the explicit statement by the TAR, do you still wish to maintain that the radiative forcing as calculated does not allow for overlap with H2O in the tropics?

    2) The passage you quoted, it was not a figure caption, did not say otherwise, it just did not specify a fact that was well known. Further, the FAQ plus Fig 2 of the FAQ which I reproduced was not added afterwards. It can be found on page 135 of the PDF reproduction of the original report for anybody interested. What is more, the figure 2.20A on which it is based (page 203) has the same heading.

    And if that is not enough, we read in the executive summary of Chapter 2:

    "The combined anthropogenic RF is estimated to be +1.6 [–1.0, +0.8][2] W m–2, indicating that, since 1750, it is extremely likely[3] that humans have exerted a substantial warming influence on climate. This RF estimate is likely to be at least five times greater than that due to solar irradiance changes. For the period 1950 to 2005, it is exceptionally unlikely that the combined natural RF (solar irradiance plus volcanic aerosol) has had a warming influence comparable to that of the combined anthropogenic RF."

    (My emphasis)

    Seeing you bring up the Summary for Policy Makers, we read there:

    "Changes in the atmospheric abundance of greenhouse gases and aerosols, in solar radiation and in land surface properties alter the energy balance of the climate system. These changes are expressed in terms of radiative forcing,[2] which is used to compare how a range of human and natural factors drive warming or cooling influences on global climate. Since the TAR, new observations and related modelling of greenhouse gases, solar activity, land surface properties and some aspects of aerosols have led to improvements in the quantitative estimates of radiative forcing."

    You will notice the footnote after the introduction of the term "Radiative Forcing". That footnote reads:

    "Radiative forcing is a measure of the influence that a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. Positive forcing tends to warm the surface while negative forcing tends to cool it. In this report, radiative forcing values are for 2005 relative to pre-industrial conditions defined at 1750 and are expressed in watts per square metre (W m–2). See Glossary and Section 2.2 for further details."

    Should we check the glossary as well, or is my point sufficiently made?

    This is a very minor, an absolutely trivial point, except for one factor. It is one thing for a Professor of Climatology with, I must add, a very distinguished career, to make a simple mistake on a fact you would expect him to know well. It is quite another to try and save face by making "facts" up. Knowledge is not so often found in this world that it can be thrown away in face saving excercises.
  • The Deep Ocean Warms When Global Surface Temperatures Stall

    Albatross at 02:27 AM on 6 October, 2011


    I'm sorry but you are saying an awful lot without really saying anything substantive, and are not raising issues that have not already been dealt with in the literature.

    I encourage you to read Lau and Weng (1999), AchutaRao et al. (2007), Lyman and Johnson (2008), Domingues et al. (2008), Levitus et al. (2009), or DelSole et al. (2011). These papers deal with the sampling and instrument issues, and they all note that decadal variability is evident in the ocean SSTs and OHC. What scientists are now interesting in determining is what exactly is happening during hiatus periods, and models are a very useful tools for such experiments/investigations.

    "I personally do not consider the periods before [1995] then to be valid until I see proof of the input data."

    That is your opinion and not that of the scientists who work in the field. As for the reliability of the early OHC data, Lyman and Johnson (2008) conclude:
    "From 1955 to 1966, in situ ocean sampling is inadequate to estimate accurately annual global integrals of the proxy upper OHCA. During this period, the SI for the sampling pattern of any given year underestimates the 13-yr trend in proxy OHCA from 1993 to 2006 by around 70%, and confidence limits for the WI are often very large. From 1967 to 2003 there appear to be sufficient data to estimate annual global integrals. "

    So we can perhaps agree that one should be looking at data since ~1967 and not 1955. The hiatus periods identified by Rob Painting include that interval of what is deemed to include reliable data. More information on the various OHC chronologies can be found here

    But if you wish to insist that the data are not reliable prior to 1993, then also consider Willis et al. (2004) and Lyman et al. (2010). Both these papers show robust warming of the oceans between 1993 and 2003 and between 1993 and 2008, respectively.

    You claim "Argo floats switch off near the surface and in any case only operate in deep waters". That is not an accurate description. There are two standard mission operations:

    "In the simple mission, the float descends to a certain depth, often 2000m, and then begins its temperature and salinity profile from that depth. In the park and profile mission, the float descends to a certain depth, 1000m is recommended, and then descends to 2000m to start the temperature and salinity profile. In the beginning of 2010, 70% of floats profile to depths greater than 1500m. Another 20% profile to between 1000 and 1500m."
  • The Deep Ocean Warms When Global Surface Temperatures Stall

    Micawber at 23:05 PM on 3 October, 2011

    [snipped] There are few actual reliable in situ observations especially in the critical near-surface layers.
    Vecchi et al. (2008) suggested anomalies between HadCru and NOAA SST mid-twentieth century data-sets were due to change in measurement methods from buckets to seawater intake to satellite.
    (Vecchi, G. A., A. Clement, and B. J. Soden (2008), Examining the tropical Pacific’s response to global warming, EOS, 89(9), 81, 83.)
    A similar report appeared about the same time in Nature:
    Thompson, D. W., J. J. Kennedy, J. M. Wallace, and P. D. Jones, (2008), A large discontinuity in the mid-twentieth century in observed global-mean surface temperature, Nature, 453, 646-649

    Seawater intake temperatures were substituted for bucket measurements particularly on US ships during WWII to minimise potential for enemy action during measurements especially at night. A statistical analysis of WMO data suggested a possible error was due to engine room warming of the intake waters. This is included in textbooks as a given (eg Emery & Thomson (2001), but there is no proof and the physics is conclusively negative.
    (Emery, W. J., and R. E. Thomson, (2001) Data analysis methods in physical oceanography, Elsevier, ISBN 044450757566, 638pp)
    Indeed a US ONR report suggested engine room warming was extremely unlikely. My calculations suggest that engine room warming of incoming seawater even at air temperatures of 50oC is negligible using realistic flow rates, pipe size and length. Certainly the 0.3oC correction applied is physically unlikely and in the wrong direction.
    Moreover, there is very strong evidence of substantial temperature gradients in the near surface layers. A temperature gradient of minus 0.1oC/meter has been measured in all oceans with substantially larger or smaller variations depending on the ocean and season.
    (Federov, K. N., and A. G. Ostrovskii (1986), Climatically Significant Physical Parameters of the Ocean, IOC Time series of ocean measurements Vol. 3 – 1986 IOC Tech. Ser. 31, UNESCO, 9-31.)
    Soloviev, A V., R Lukas,(1997) Large diurnal warming events in the near-surface layer of the western equatorial Pacific Warm pool Deep Sea Res., 1055-1076
    Near Surface dynamics are extensively discussed in the Soloviev and Lukas 2006 book that has recently been issued in paperback
    The near-surface layer of the ocean By Alexander Soloviev, Roger Lukas Springer 2006 - 572 pages

    Much of the HadCru ocean data are taken from the Voluntary Observing Ship (VOS) program of WMO. Seawater intake temperature was routinely measured as sea surface temperature. Corrections were routinely applied to obtain ‘corrected’ surface temperatures. There is great doubt as to what the relationship of the seawater intake temperatures so derived is to the actual surface or skin temperature given the certain knowledge of substantial temperature and salinity gradients throughout the oceans.
    The problem is particularly severe from 1955-1995 because there is no record of seawater intake depth on the VOS fleet for that period.
    The problem, I believe, is further complicated by the substitution of supposed sea surface temperature (SST) for marine air temperature (MAT) in model data. Standard 10m wind data and Stevenson Screen temperature data are used over land. But over water surface wind and SST are used. If the temperature in question is from some unknown depth and correlation to MAT is poor, we are likely to have [snipped]
    We now have accurate skin temperature and salinity measurements using infrared satellite data. But there is still little data in the upper 10m – 50m of the oceans. Argo floats switch off near the surface and in any case only operate in deep waters. There are huge changes occurring with coastal run-off and ice melt that affect coastal regions and have impact on ocean heat, vertical circulation as well as acidification as detailed in other SkS posts.
    It is pretty clear that models are not working eg the unexpected rapid arctic ice melt. It is only a year since everyone was predicting that the ice was actually increasing in area. It was only with the discovery, by getting out and looking, that the ice was mostly single year rotten ice, not largely composed of dense thick multi-year ice that the true decline was established as fact. Satellites just did not give those kind of details.
    So this is a plea for detailed near-surface ocean data especially in near-shore regions where the most rapid change will occur.
    Until we have better observational data in the near-surface and numerical models that incorporate the full range of air-sea interaction, we should not place a lot of faith in model-based suggestions let alone treat them as forecasts or predictions.
  • Santer et al. Catch Christy Exaggerating

    Albatross at 02:00 AM on 16 September, 2011

    I'm surprised how little attention this important paper has received here at SkS. It is an important paper, IMHO, because it provides some concrete guidelines on the times scales that need to be considered for the purpose of evaluating models and for determining trends.

    It is also important, of course, because it shines a light on how "skeptics", even prominent ones who should know better (like Lindzen, Michaels and Pielke Sr.) love to cherry pick to arrive at a pre-determined answer and how they love to exaggerate, in this case Dr. John Christy.

    For example, recall how Lindzen was implicated in a set-up for Phil Jones? The "trap" was to try and demonstrate that there had been no statistically significant warming (which "skeptics and deniers of AGW took to incorrectly mean no warming) between 1995 and 2009 (15 years) in the HadCRUT global temperature dataset? Well, as it happens if one includes just one more year (16 years) the warming between 1995 and 2010 was statistically significant at the 95% confidence level.

    The 16 years worth of data required to achieve that level of confidence in the HadCRUT data is consistent with the 17 years identified by Santer et al. (2011). So the challenge for "skeptics" now will be to cherry pick a dataset and a time window that shows not statistically significant warming for at least a 17 year period-- and then they can try and rehash the "planet is cooling" myth again ;)
  • Santer et al. Catch Christy Exaggerating

    Kevin C at 23:58 PM on 13 September, 2011

    Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.
    I've heard this number a number of times, but never managed to track down a source.

    So recently I tried working it out for myself, learning the statistics from some of Tamino's old posts on ARMA and autocorrelation, as well as Lucia, Science of Doom and Kelly's climate charts and graphs.

    The standard deviation of the residual noise in the HADCRUT record after fitting a linear trend (1975-2010 as Tamino or 1913-1944 as per Lucia) is a little over 0.1C. Several different methods seem to give estimates of the effective number of parameters as ~1/6 of the number of months. So the standard error on the OLS trend needs scaling up by ~2.5x.

    So, having made that correction, how many years of data do you need for 2σβ to be less than 0.017C/yr? About 11, on average. (And using the same method I agree with Phil Jones that warming since 1995 becomes significant only when you include the 2010 data, so I don't think I'm doing anything badly wrong.)

    So I'm itching to find out what Santer has done. Am I asking the wrong question? Should I be looking at the number of years required for the trend to be statistically significant more that 95% of the time? 95% significance 95% of the time?

    It would be nice to never have to answer another 11 year trend again. But - it's AGU paywalled. Sigh.
  • Mythic Reasoning about Climate Uncertainty

    muoncounter at 08:44 AM on 29 August, 2011

    chris#9: That is a stunning find; the paper is indeed available in pdf from your link - thanks!

    It is quite a difference from the current party line, which includes:

    And finally, I’m sure you knew it had to be coming:

    Irene’s got a middle name, and it’s Global Warming

    The quote is from Bill McKibben, cited in a post at Collide-a-Scape. Apparently Kevin Trenberth’s reversal of the null hypothesis has taken hold in certain segments.

    The 2006 paper quotes Trenberth as inspiration:

    Trenberth (2005) published a commentary in Science raising the issue as to whether the increase in North Atlantic hurricane activity since 1995 could be attributed to global warming. This paper motivated us to begin looking at global hurricane data.

    Here is Curry's own reversal of the null hypothesis:

    while there are uncertainties and heterogeneities in the global hurricane dataset, the magnitude of the trend identified by WHCC is sufficiently large that the null hypothesis must be rejected based upon the currently documented uncertainties in the dataset.

    Acknowledgments go to Trenberth, Emmanuel and others - most notably the arch-enemy Joe Romm; a far cry from thanking the denizens of ClimateEtc for their 'contributions.'

    I believe this is known in political circles as a flip-flop.
  • Why Wasn't The Hottest Decade Hotter?

    Riccardo at 08:26 AM on 15 July, 2011

    you need to distinguish between long term trend (Hansen) and short term variability (Kaufmann). And also understand that Jones didn't say there has been no warming.
  • It hasn't warmed since 1998

    Dikran Marsupial at 22:41 PM on 3 July, 2011

    @mark The central limit theorem does indeed suggest that the averaging of temperatures at stations at different location means that a Gaussian noise model is appropriate, but only for a particular time point. To see why this is the case, imagine some AM radios that are affected by mains hum. Each will have a noise component that is due to the electronic components in the radio, these are independent, so the noise for the average signal over many such radios will have a corresponding Gaussian component. However, the mains hum on all the radios will be in phase and will be reinforced in the averaged signal, and will have the same [scaled] distribution as the mains hum measured at any one of the radios.

    Another way of looking at it, cyclical data is easily confusable with data containing a step change, but how likely is it to see a cyclic pattern in Gaussian white noise? A lot less likely than in data with autocorrelation or cyclical noise.

    You are not being at all dense, the central limit theorem is hardly stats 101!

    I checked the archive at the Journal of Forecasting, it hasn't been published yet.

    For the multiple hypothesis testing issue, there are standard methods to deal with this, but they are generally overly optimistic or pessimistic. What I would do is generate a large number of model runs using a GCM where the only forcing was from CO2 and see how many produced a non-significant trend at some point during a 40 year period via the models internal variability. The forty year period is chosen since worries about global warming began to gain acceptance in the early 70s, the test is "at some point" because we are asking if cherry picking is the issue, so the "skeptics" would make the claim as soon as such a period ocurred.

    Easterling and Wehner (who Stockwell and Cox claim to refute) did almost that, in that they looked at model output and found that decadal periods of little or no warming were reproduced by the models (although opf course the models can't predict when they will happen). This means that the observed trend since 1995/8 is completely consistent with model output. Easterling and Wehners' result shows that cherry picking is a possibility; it isn't necessarily deliberate cherry picking, but the skeptics have never performed an analysis that shows the ressult is robsut to the multiple hypothesis testing issues.

    For the removal of ENSO, see the Fawcett and Jones paper mentioned in the intermediate version of this article. If you just look at the data:

    you can see there isn't much evidence of a step change in 1997 if you account for ENSO.

    The real problem with the paper is the straw man of a linear centennial trend. AGW theory doesn't suggest a linear centennial trend is reasonable, so showing a model with a break-point is statistically superior to something that AGW theory does not predict is hardly evidence against AGW.

    I also remember some comment about solar forcing being better correllated with temperatures than are CO2 concentrations, and conclude that CO2 radiative forcing is not significant (or words to that effect). However, that is another straw man, the mainstream position on AGW does not say that co2 radiative forcing is dominant on a centennial scale (and that solar forcing is responsible for much of the warming of the 20th century). This is both a straw man and a false dichotomy, it isn't one thing or the other, but a combination of both. Reviewers at the Journal of Forecasting might not be suifficiently familiar with the climatology to spot that one.

    What I am basically arguing is that statistics should be used to gain knowledge of the data generating process (in this case climate physics). If you ingore what is already known about the data generating process and adopt a "null hypothesis" (e.g. linear centennial trend) that is known a-priori to be incorrect, then statistical methods are likely to be deeply misleading. It is a really good idea for statisticians to collaborate with climatologists, as together they have a better combination of climate science and statistical expertise than either has on their own. This paper, like McShane and Whyner (sp?) and Fildes and Kourentzes, is an example of what happens when statisticians look at climate data without fully immersing themselves in the climatology or getting their conclusions peer-reviewed by climatologists.
  • Climate half-truths turn out to be whole lies

    skywatcher at 19:49 PM on 28 June, 2011

    Keeping it on topic (and not about droughts), it's worth pointing out, in true Phil Jones style, that the warming in the HadCRU dataset has been statistically significant since 1995, and stronly significant over the past 20 or 30 years (as it has in all major climate datasets, global or near-global). So Carter really doesn't have a leg to stand on in suggesting 'it's cooling', unless he wants to paint himself into a very tight corner, given the obvious trend.
  • Phil Jones - Warming Since 1995 is now Statistically Significant

    snapple at 21:25 PM on 16 June, 2011

    Denialist "cherrypicking" from this BBC editorial really opened my eyes. Even I know what statistically significant means, but most people don't.

    You did not mention in your article what Pravda and the 9-11 Truther publication "Rock Creek Free Press" said about Dr. Jones.

    They made the same claims as the media you mention. Pravda even cited FOX News as their source.

    Pravda was actually slightly more accurate than the Daily Mail or the Fox News article they cited because they mentioned "statistically significant," but they didn't explain that term.

    The Pravda article was titled "Phil Jones Backs Out Of Global Warming Fuss"
    (2-16-10), but Pravda actually did report:

    The scientist behind the so-called "climate-gate" e-mail scandal now admits there has been no statistically significant global warming since 1995.

    These papers left out important information that Phil Jones told the BBC and that the BBC did report:

    BBC: How confident are you that warming has taken place and that humans are mainly responsible?

    Phil Jones: I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity.
  • Phil Jones - Warming Since 1995 is now Statistically Significant

    JMurphy at 04:26 AM on 16 June, 2011

    I think Phil Jones gave an answer which was correct, easily understandable and honest. The fact that those in denial used a version of his answer to try to claim things that Phil Jones did not mean or say ("Global Warming in Last 15 Years Insignificant, U.K.'s Top Climate Scientist Admits" from FOX NEWS, and "Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995" from the DAILY MAIL - both headlines are demonstrably false), simply shows how despicable and dishonest they are.
    No matter how Jones had answered, his words would still have been twisted and abused.

    Don't have a go at Jones for being naive, credulous or whatever - his answer would never have been perfect enough to have disallowed its use as propaganda by those who thrive on disinformation. Have a go at those who misuse and misinform.
  • Phil Jones - Warming Since 1995 is now Statistically Significant

    Bob Lacatena at 05:15 AM on 14 June, 2011

    The only way Jones could have crafted a perfect answer would have been to him to have seen everything coming (maybe by running an ensemble of interview-reaction models using OUTFOX-E, a popular Global Confusion Model) and then saying something along the lines of:

    "Well, there is a statistically significant warming trend since X, but the period from 1995 to the present is simply to short to properly use statistical methods to answer your question."

    That answer, too, would have been a bit of a white lie (if the upward trend were strong and steady enough, it would have been possible, so saying it's not possible is not strictly true, it's just not true as things turned out), but... really, I think it's the only thing he could have said to avoid all that came after.

    My advice to everyone is to get a supercomputer, and run several thousand iterations of OUTFOX-E before you post a even a simple comment here!
  • Phil Jones - Warming Since 1995 is now Statistically Significant

    dana1981 at 04:24 AM on 14 June, 2011

    To clarify the new 2001 cherrypick issue, HadCRUT is the only dataset which shows a (miniscule) cooling trend over that period. As noted in the post above, HadCRUT is also not a complete global dataset, as it excludes much of the Arctic. The global surface temperature datasets, and even the satellites, show a warming trend since 2001, though none are statistically significant as it's too short of a timeframe (also discussed in the post).

    I find it a bit silly, in comments on an article about cherrypicking data since 1995, that we're now cherrypicking data since 2001.
  • Of Averages & Anomalies - Part 2A. Why Surface Temperature records are more robust than we think

    JMurphy at 00:14 AM on 11 June, 2011

    With regard to CRU, it's good to see Phil Jones finally clearing-up the 'not significant' comment so (wilfully) misunderstood by the so-called skeptics :

    Global warming since 1995 'now significant'

    I'm sure we will now no longer see this 'misunderstanding' in such a prominent position all over the Denialosphere...
    (Oh, is that a flying pig ?)
  • Are you a genuine skeptic or a climate denier?

    KR at 14:05 PM on 1 June, 2011

    J. Bob - Your reference to climate4you was, indeed, fascinating.

    Majority of plots 1979 on only, very few instrumental records prior to that, most of those from local areas. Heavy focus on GISP2 (a single ice core, not a global temperature), several Central England temperature records (hmm, seeing a pattern here?), statements such as ""net changes since 1998 appear to be small" (see Did global warming stop in 1998, 1995, 2002, 2007, 2010?)...

    Given the cherry-picking and short term focus, I don't know that I would trust the data or the presentation thereof from that site. It doesn't meet my requirements for presenting all of the data, avoiding cherry-picking, or using realistic periods of time for determining climate trends. I would not consider that a good resource - go to the peer reviewed papers!
  • A Convention for Persons Displaced by Climate Change

    Dan Olner at 18:31 PM on 20 April, 2011

    Charlie A: I responded to that meme just the other day: it's not true. The subject was *environmental* refugees. That's a much larger category: I quote extensively from the original research in that link. Factors affecting environmental refugees from the original 1995 report: food and agriculture; water shortages; deforestation; desertification; population pressure; urbanization and mega-cities; unemployment; poverty; extreme weather events. Global warming is mentioned as a multiplier that will make the issue worse, but the subject was never "climate refugees."

    What's more bizarre to me: this all seems to have started from that Asian Correspondent piece, where they attempt to show the predictions were wrong by citing census data from four tropical islands. Does that strike you as a good way to assess the environmental refugee problem? (Or indeed the "climate refugee" problem they thought they were attacking?)

    I haven't dug much deeper, but there does appear to be some confusion among people writing the UNEP press releases as well, which hasn't helped. However, you need to go back to Prof Norman Myers' original research. In 1995, there were already, by some estimates, 25 million environmental refugees. He was estimating (not even really forecasting) another 25 million in the following 15 years - though if you read the research, these numbers are surrounded with caveats. For some reason, critics seem to ignore all the caveats. As far as I know - and I'd love to hear from others here - there has been no systematic attempt to define and measure the problem since then. Perhaps for good reason: as a migration issue, it's very complex - again, something Myers argued in his original piece.

    Here's Myers: "These estimates constitute no more and no less than a first cut assessment. They are advanced with the sole purpose of enabling those to ‘get a handle’, however preliminary and exploratory, on an emergent problem of exceptional significance." He's right of course: it is a massively important issue. That people should dismiss it so lightly, based on someone checking four island's census numbers, hardly suggests to me they have any interest in actually trying to understand the problem. Anyone unable to see the difference between "climate" and "environment" refugees, and the relations betwen the two, is going to have problems contributing to this discussion seriously.
  • Christy Crock #4: Do the observations match the models?

    Arkadiusz Semczyszak at 22:09 PM on 19 April, 2011

    I had to take a work ...

    ... but ...

    You could say that humanity has changed the structure of the Earth’s atmosphere.

    Do not "humanity" but Mt. Pinatubo, in the figure above there is no trend (is zero) before and after the 1992-5 year. Change is swept - Mt. Pinatubo ozone depleting ...

    And where they do diverge from climate models, the observations are usually even more alarming.


    If we are in the tropics ...

    On this page, "like fire" avoids the topic "Tropical Cyclones and Climate Change".

    Knutson 2011:

    Vertical profile of temperature change.
    “Interestingly, observed vertical profiles of air temperature changes since about 1980 using radiosondes and some satellite records actually show a relatively uniform warming with height through the troposphere.” “ Therefore I consider it more likely that data problems with the radiosonde and satellite temperature datasets have led to unreliable observed temperature trend profiles that falsely indicate a substantial destabilization of the tropical atmosphere since 1980.

    Lower stratospheric temperatures.
    A variant on the theme of vertical profile of temperature changes is the recent study of Emanuel10, who reports that a cooling trend in the lower stratospheric temperatures in recent decades implies an increase in potential intensity of hurricanes in the Atlantic.” “While the lower stratospheric temperature decrease remains a subject of further investigation as to its veracity and cause, preliminary results with another (dynamical) model from GFDL (G. Vecchi, personal communication) suggest that lower stratospheric temperatures do not affect tropical storm counts substantially in that model. [...]”

    “For example, one can speculate that ozone changes [I told you!] and related atmospheric effects could have affected tropical upper tropospheric temperatures enough to change tropical cyclone activity substantially.”

    “Those internal variability arguments typically suggest that hurricane activity will likely return toward pre-1995 levels sometime in the next few decades. In any case, the potential links between lower stratospheric and/or upper tropospheric temperatures, climate forcings, and hurricane activity mentioned here remain speculative.

    “While the simulated changes in TC activity and in sea surface temperatures in their study are dramatic, the implications of their simulations for climate changes over the next century or so remain speculative.

    “First, it is possible that 21st century changes in tropical cyclones will be less potentially damaging than the scenarios outlined in the projections section.” “Global climate transient sensitivity or sea level rise could be at the low end, or even lower than, the range shown in IPCC AR4.”
  • The e-mail 'scandal' travesty in misquoting Trenberth on

    villabolo at 10:58 AM on 13 April, 2011

    @46 Gilles:

    "A piece of evidence is shown by the fact that during intense El Niño/la Niña events, like in 1998, 2005, or 2010, the average surface temperature experience "huge" variations of 0.5°C or more, corresponding to several decades of "average" trend, in only some months - but of course the energy content of the Earth has not been able to vary so much , so rapidly ! so average surface temperature is *not* a precise indicator of global energy content."

    Please see my article on El Niño/La Niña events, and how their fluctuations are indicative of the fact that both El Niños and La Niñas are increasing in temperature (and this with a cooler sun starting in 2002!).

    What is the relevance of those "huge" variations of .5C when La Niña's lowest temperatures, as well as El Niño's highest, are both above those before 1995/1998? You can eyeball it here:

    First note the green and pink lines and how they ratchet up. Then the brown trend line going up, "huge" variations notwithstanding.

    These temperatures are increasing overall, irrespective of the variations you mentioned. Where does that heat go to? The oceans absorb over 90% of it. Oceans have been steadily rising in heat content with the usual fluctuations. Those fluctuations make no difference, no matter how large they are, to the long term trend; as can be seen here:

    Now a reminder. You said:
    "so average surface temperature is *not* a precise indicator of global energy content."

    @50 Ian Forrester said:
    "Who has ever said that it was? The energy content of the globe is found in a number of places some of which are accurately measured (surface and oceans down to 700 metres) and others which cannot be accurately measured with today's technology (deep oceans).

    The ocean temperatures, of course, is what we can measure down to 900 meters. Do you seriously think that the heat pulse travelling down the ocean depths is going to stop where our instruments just happen to be?

    Simple deduction indicates where the unaccounted for energy is going to be. In fact, since the heat pulse is obviously not going to stop at the 900 meter level, there has to be unaccounted for energy below it! In fact, it would be amazing if Trenberth did not have that accountability problem.
  • Climate Sensitivity: The Skeptic Endgame

    The Inconvenient Skeptic at 17:49 PM on 2 March, 2011

    Since CO2 levels were 310 ppm in 1950. It was only after 1960 that the CO2 levels started to significantly increase. The claim that warming prior to the increase in CO2 levels is caused by CO2 levels is incoherent. Since more than half of the warming in the past century took place before 1950 I see a flaw in your argument that CO2 has caused all the warming. There was also no significant trend in global temperature from the 1958-1995 while CO2 levels in the same period increased from 310-360ppm. The early date is used only because that is the start of reliable CO2 data. No temperature trend for almost 40 years while CO2 was climbing. There was significant warming after the 1998 El Nino and there was warming in the 1930's when CO2 was low and stable. But the period that showed the most change in CO2 did not show warming. That shows an interestingly low climate sensitivity to CO2.

  • It's cooling

    les at 07:20 AM on 21 February, 2011

    140 Mr Anderson

    Also read

    Your welcome.
  • Meet The Denominator

    john byatt at 21:16 PM on 13 February, 2011

    Plenty of stuff like this on the internet,

    “Poptech's again referring to his own self-publi­­­­shed "popularte­­c­hnology­" webpages, which are riddled with disinforma­­­­­tion and lies.

    For example, when are you going to remove the following patent, science denier tabloid-so­­­­­urced lie* from your "popularte­­­chnology­" webpages, Poptech?

    "Climatega­­­­­te U-turn as scientist at centre of row admits: There has been no global warming since 1995"

    Oh, right - as you Poptech have repeatedly told us you are "never" going to remove that lie, thus demonstrat­­­­­ing that you have no intent or interest in promoting the truth about climate science.
  • Articgate: perpetuating the myth that Arctic sea ice has recovered

    MarkR at 23:15 PM on 8 February, 2011


    'As predicted' is loaded, projected changes in Arctic ice include a full range with associated uncertainty. The possibility of further area collapse was mooted, but was far from a mainline prediction as far as I can tell. Here's a paper from '07 where they help explain it. 2007 was far below model projections and since then we've stayed below model projections.

    Phil Jones said no statistically significant warming at the 95% confidence level from 1995-2009. It is now (using '95-'10) statistically significant at that level. This is from the HadCRUT3 dataset which is only an atmosphere/surface measurement. If you look at ocean heat content, or latent heat invested in melting ice, or sea level (which integrates over those) then up to 2003 global warming was obvious in all of them. Since '03 we've seen significant rises in sea level and loss of ice, plus probably in abyssal warming, but perhaps not in 0-700m ocean heat content.

    Total polar ice is not decreasing? The data say that it is. Sure, Monckton and some other skeptics say otherwise, but I tend to run with the data.

    Antarctic sea ice is covered elsewhere on here. :)
  • Hurricanes aren't linked to global warming

    muoncounter at 13:22 PM on 20 January, 2011

    #20: "either not warming at all recently ..."

    We know that's not true.

    "... or there's no connection whatsoever between temperature and storminess."

    No connection whatsoever is a strong phrase in this context. From Jeff Masters:

    Tomas' formation ties 2010 with 1995 and 1887 for 3rd place for most number of named storms in an Atlantic hurricane season. Only 2005 (28 named storms) and 1933 (21 named storms) were busier. ... The intensification of Shary and Tomas into hurricanes today brings the total number of hurricanes this season to twelve, tying 2010 with 1969 and 1887 for second place for most hurricanes in a season. The record is held by 2005 with fifteen hurricanes ...
    -- emphasis added

    The last time this came up, you argued for some sort of ad hoc statistic by summing Safir-Simpson number of US landfalling storms annually. This completely discounts storms that bypass the continental US (which seems arbitrary) and ignores tropical storms (which seems capricious). FYI: See arbitrary and capricious.

    Here's the graph of named storms prior to the 2010 season:

    which is complicated, but seems to be vaguely increasing over time, especially since the 1920s.

    The conclusion in prior threads was this particular aspect of the science isn't settled. So 'no connection whatsoever' is hardly warranted.

    And then there are those nasty Pacific storms... this is about global warming after all.
  • Coral: life's a bleach... and then you die

    Arkadiusz Semczyszak at 21:02 PM on 13 January, 2011

    Corals are my favorite topic.

    Do volcanic eruptions enhance or diminish net primary production? Krakauer and Randerson, 2003. :
    “Up to decadal-scale ocean cooling tentatively linked to volcanic eruptions has also been found in a study of south Pacific coral [ Crowley et al. , 1997]. Nevertheless, it appears puzzling that the maximum growth reduction seen in this study lags by several years the period of maximum eruption cooling.”

    Robecknew, 2003.: “It was so cold that winter that Jerusalem experienced rare snowfall and coral at the bottom of the Red Sea died, because the water at the surface cooled and convectively mixed the entire depth of the water [ Genin et al. , 1995]. The resulting enhanced supply of nutrients produced huge algal and phytoplankton blooms, which smothered the coral. This coral death had only happened before in winters following large volcanic eruptions [ Genin et al. , 1995].”

    Coral reef calcification and climate change: The effect of ocean warming. McNeil, Matear and Barnes, 2004.:
    “Our analysis suggests that annual average coral reef calcification rate will increase with future ocean warming and eventually exceed pre-industrial rates by about 35% by 2100. Nasza analiza wskazuje, że średnia roczna stopa koral rafa zwapnienie wzrośnie z przyszłego ocieplenia ocean, a ostatecznie przekracza sprzed rewolucji przemysłowej, stawki o około 35% do roku 2100. Our results suggest that present coral reef calcification rates are equivalent to levels in the late 19th century and does not support previous suggestions of large and potentially catastrophic decreases in the future.”

    Coral adaptation in the face of climate change. Baird and Maynard, 2008., speaks of the rapid adaptation of corals to climate change.

    4 Years After Tsunami Corals Stage Comeback, 2008.:
    “ A team of scientists from the New York-based Wildlife Conservation Society (WCS) has reported a rapid recovery of coral reefs in areas of Indonesia, following the tsunami that devastated coastal regions throughout the Indian Ocean four years ago today. The team, which has surveyed the region's coral reefs since the December 26, 2004 tsunami, looked at 60 sites along 800 kilometers (497 miles) of coastline in Aceh, Indonesia. The researchers attribute the recovery to natural colonization by resilient coral species, along with the reduction of destructive fishing practices by local communities.”
    “Multiple linear regression models show that high mean sea surface temperatures, high acidity, and low frequencies of high temperature anomalies account for 45% of the variation in proportion of Clade D at all examined sites. Models of future Indo-Pacific climate predict that areas now unsuitable for Clade D will rapidly change to favor Clade D dominance: the front of Clade D suitability is predicted to move across the subtropical South Pacific at rates of 20-49 km per year. Many of these areas currently host low levels of Symbiodinium D, raising the concern that environmental change will sweep over areas faster than dispersal and population growth can add Clade D symbionts to reefs.”

    CO2, Global Warming and Coral Reefs: Prospects for the Future . Idso, 2009.:
    “Lough and Barnes (1997) found that "the 20th century has witnessed the second highest period of above average calcification in the past 237 years."

    Currently, however: “The study shows that the biggest and most robust Porites corals on Australia's Great Barrier Reef have slowed their growth by more than 14 percent since the "tipping point" year of 1990.” "The data suggest that this severe and sudden decline in calcification is unprecedented in at least 400 years," Lough: "It is cause for extreme concern that such changes are already evident, with the RELATIVELY MODEST CLIMATE CHANGES observed to date, in the world's best protected and managed coral reef ecosystem,"
    ... however: "The causes of this sharp decline remain UNKNOWN, but our study suggests that the combination of increasing temperature stress and ocean acidification may be diminishing the ability of Great Barrier Reef corals to deposit calcium carbonate,"
    Dr Lough said there had been some concern that coral growth has been declining in recent times. "However, data from density bands place these results into a larger context. Density bands show that coral growth and calcification on the Great Barrier Reef vary considerably over time.”
    "Coral records show that there have been several major increases and decreases over the past several centuries. “
    Generally Conclusion:
    “the CURRENT DECLINE appears to be a RETURN TO MORE NORMAL GROWTH CONDITIONS from high growth rates earlier this century".
  • Climategate: Impeding Information Requests?

    sailrick at 07:50 AM on 27 November, 2010

    Regarding CRU scientists not trusting the motives of McIntyre and McKitrick:
    I would say they had good reason to not trust their motives.

    A good example is the ISPM (Independent Summary for Policymakers) published by the Fraser Institute. It was issued days after the release of the Summary for Policy Makers by the IPCC, in Febuary 2007. At this time, Ross McKitrick was head of the Fraser Institute, a well know industry front group.

    ( Interesting that they had their Independent Summary ready just days after the IPCC's Summary for Policy Makers. )
    Anyway, here are some examples of Fraser Institutes distortions of science then.

    According to the Fraser Institute:

    "An independent review of the latest United Nations report on climate change shows that the scientific evidence about global warming remains uncertain and provides no basis for alarmism."

    Just the use of the word "alarmism" should ring a bell that this is not an unbiased paper. It's a derisive term used by the denier crowd, and you wouldn't find such terms in any real scientific study.

    The ISPM claimed that the report from the IPCC

    "is neither written by nor reviewed by the scientific community."

    This was not true. Here's what Desmogblog says about it.

    "In fact, the IPCC summary was written and reviewed by some of the most senior climate scientists in the world, without political or bureaucratic input . And the Fraser Institute’s 'scientific' staff - which is led by an economist - includes a group of junior or retired scientists, most of whom have direct connections to energy industry lobby groups."

    Fraser Institute said:

    "There is no compelling evidence that dangerous or unprecedented changes are underway."

    Compare that claim with what Dr Andrew Weaver, lead IPCC author and chairman of the Canada Research in Climate Modelling and Analysis says.

    "The IPCC report presents 1,600 pages of compelling evidence, that’s the whole point."

    Sourcewatch says that Fraser Institute's ISPM errors include:

    "Several incorrect statements concerning tropospheric temperature trends derived from satellite data."

    "Misdentification of peak temperature year in GISS and NCDC global surface temperature data sets (1998 given instead of 2005)."

    "Mistaken citation of projected sea level rise to 2100 of only 10-30 cm, instead of 21-48 cm given by IPCC"

    "Several examples of "cherrypicking", inexplicable omissions and misrepresentations."

    Frazer Institute's ISPM states:

    "There would also appear to be an unstated implication that temperature may have reached a plateau or even decreased since 1998."


    "the ISPM fails to mention that the smoothed temperature statistic for the combined data sets continued to show an upward trend through 2005."

    "The ISPM conveniently omitted the following information from the IPCC report."

    "2002 to 2004 are the 3rd, 4th and 5th warmest years in the series since 1850
    Eleven of the last 12 years (1995 to 2006) ... rank among the 12 warmest years on record since 1850."

    "Surface temperatures in 1998 were enhanced by the major 1997–1998 El Niño but no such strong anomaly was present in 2005."

    More on Fraser Institute's twisting of science at:
  • Skeptical Logic Can't Save Greenland Ice - for that you need to stop climate change

    Berényi Péter at 01:05 AM on 16 October, 2010

    Posted by gpwayne on Friday, 15 October, 2010 at 14:59 PM
    Climate change skeptics like Marc Morano employ gross exaggeration to dismiss or diminish the potential disruption that climate change is likely to bring about. In the Inhofe EWP press blog, Morano made much of this statement [...]

    That blogpost is more than three years old, dated 9:39 AM ET, July 30, 2007.

    Latest Scientific Studies Refute Fears of Greenland Melt
    Posted By Marc Morano

    What he says is not entirely unsupported. For the sake of fairness you could at least dig up references from that post or peer reviewed literature backing them.
    1. Annals of Glaciology
      Volume 46, Number 1, October 2007 , pp. 209-214(6)
      DOI: 10.3189/172756407782871558
      20th-century glacier fluctuations on Disko Island (Qeqertarsuaq), Greenland
      Jacob C. YDE & N. Tvis KNUDSEN
      VOL. 33, L11707, 5 PP., 2006
      Greenland warming of 1920–1930 and 1995–2005
      Petr Chylek, M. K. Dubey & G. Lesins
    3. Science 11 November 2005:
      Vol. 310. no. 5750, pp. 1013 - 1016
      DOI: 10.1126/science.1115356
      Recent Ice-Sheet Growth in the Interior of Greenland
      Ola M. Johannessen, Kirill Khvorostovsky, Martin W. Miles & Leonid P. Bobylev
      VOL. 111, D11105, 2006
      Extending Greenland temperature records into the late eighteenth century
      B. M. Vinther, K. K. Andersen, P. D. Jones, K. R. Briffa & J. Cappelen
    5. Science 16 March 2007:
      Vol. 315. no. 5818, pp. 1559 - 1561
      DOI: 10.1126/science.1138478
      Rapid Changes in Ice Discharge from Greenland Outlet Glaciers
      Ian M. Howat, Ian Joughin & Ted A. Scambos
    6. Science 6 July 2007:
      Vol. 317. no. 5834, pp. 111 - 114
      DOI: 10.1126/science.1141758
      Ancient Biomolecules from Deep Ice Cores Reveal a Forested Southern Greenland
      Eske Willerslev, Enrico Cappellini, Wouter Boomsma, Rasmus Nielsen, Martin B. Hebsgaard, Tina B. Brand, Michael Hofreiter, Michael Bunce, Hendrik N. Poinar, Dorthe Dahl-Jensen, Sigfus Johnsen, Jørgen Peder Steffensen, Ole Bennike, Jean-Luc Schwenninger, Roger Nathan, Simon Armitage, Cees-Jan de Hoog, Vasily Alfimov, Marcus Christl, Juerg Beer, Raimund Muscheler, Joel Barker, Martin Sharp, Kirsty E. H. Penkman, James Haile, Pierre Taberlet, M. Thomas P. Gilbert, Antonella Casoli, Elisa Campani & Matthew J. Collins
    7. IPCC Fourth Assessment Report
      Climate Change 2007: Synthesis Report
      3.2.1 21st century global changes
      Table 3.1. Projected global average surface warming and sea level rise at the end of the 21st century.
    8. The Holocene 12,1 (2002) pp. 49–58
      DOI: 10.1191/0959683602hl519rp
      A mid-Holocene shift in Arctic sea-ice variability on the East Greenland Shelf
      Anne E. Jennings, Karen Luise Knudsen, Morten Hald, Carsten Vigen Hansen & John T. Andrews
      VOL. 32, L17605, 4 PP., 2005
      One more step toward a warmer Arctic
      Igor V. Polyakov, Agnieszka Beszczynska, Eddy C. Carmack, Igor A. Dmitrenko, Eberhard Fahrbach, Ivan E. Frolov, Rüdiger Gerdes, Edmond Hansen, Jürgen Holfort, Vladimir V. Ivanov, Mark A. Johnson, Michael Karcher, Frank Kauker, James Morison, Kjell A. Orvik, Ursula Schauer, Harper L. Simmons, Øystein Skagseth, Vladimir T. Sokolov, Michael Steele, Leonid A. Timokhov, David Walsh & John E. Walsh
      Notes on Climate Change
      Syun-Ichi Akasofu
    11. Earth and Planetary Science Letters
      Volume 207, Issues 1-4, 28 February 2003, Pages 13-22
      Modern spectral climate patterns in rhythmically deposited argillites of the Gowganda Formation (Early Proterozoic), southern Ontario, Canada
      Gary B. Hughes, Robert Giegengack & Haralambos N. Kritikos
    12. Global and Planetary Change
      Volume 40, Issues 1-2, January 2004, Pages 177-182
      Global Climate Changes during the Late Quaternary
      New perspectives for the future of the Maldives
      Nils-Axel Mörner & Michael Tooley
      Vol. 23: 89–110, 2003
      Proxy climatic and environmental changes of the past 1000 years
      Willie Soon & Sallie Baliunas
      Energy & Environment
      Reconstructing climatic and environmental changes of the past 1000 years: a reappraisal (2003)
      Willie Soon, Sallie Baliunas, Craig Idso, Sherwood Idso & David R. Legates
    14. Science 11 August 2006:
      Vol. 313. no. 5788, pp. 827 - 831
      DOI: 10.1126/science.1128243
      Insignificant Change in Antarctic Snowfall Since the International Geophysical Year
      Andrew J. Monaghan, David H. Bromwich, Ryan L. Fogt, Sheng-Hung Wang, Paul A. Mayewski, Daniel A. Dixon, Alexey Ekaykin, Massimo Frezzotti, Ian Goodwin, Elisabeth Isaksson, Susan D. Kaspari, Vin I. Morgan, Hans Oerter, Tas D. Van Ommen, Cornelius J. Van der Veen & Jiahong Wen
  • Explaining Arctic sea ice loss

    The Inconvenient Skeptic at 13:58 PM on 13 October, 2010

    The Atlantic Multidecadal Oscillation (AMO) is a natural cycle. It is also known to have affected the arctic sea ice before. The instrumental record of the AMO goes back to to around 1860. In that period there are approximately records of two full cycles of the AMO.

    Since it is only possible to directly correlate the sea ice extent to the AMO since the satellites were able to measure it in 1978 other means are needed to determine the affect in the past.

    The opening of the Northwest passage is one possible method. While the first credited successful passage was in 1906 (while AMO was cool) by Roald Amundsen, the expedition ended with the ship trapped in ice for 3 years and it was completed on foot.

    The first open water expedition was completed in a period of 28 months starting in 1940. The AMO was in the warm phase during this period. More interesting is that the trip back in 1944 only took about 3 months indicating that the ice volume had decreased since the initial trip.

    Many trips after that have succeeded, but using modern icebreaking ships with heavily reinforced hulls. Those were needed because the passage was once again closed while the AMO was in the cool phase.

    The transition of the AMO was once again transitioning to warm phase and has been above average since 1995. The re-opening of the passage since then correlates well to the warming of the AMO.

    Even the record low extent in 2007 correlates to the longest sustained warmth of the current AMO. After that the AMO has cooled slightly and the extent has rebounded.

    Separating any change in ice from the warm phase of the AMO would be a difficult task at best and claiming that the decreasing extent is the "canary in the global warming coal mine" is scientifically irresponsible.

    I do not claim that the AMO is the only factor decreasing extent, but it is certainly a major factor in the current extent behavior.

    John Kehr
    The Inconvenient Skeptic
  • It hasn't warmed since 1998

    archiesteel at 03:05 AM on 10 October, 2010

    This is a response to fydijkstra in another thread, where he claimed there has not been any warming since 1998.

    fydijkstra, there has been warming since 1998, as this graph demonstrates:

    Second, 1998 was an exceptionally warm year. Using it as a starting point to determine a trend is cherry-picking at its best (not to mention the fact that the time frame is too short to indicate statistical significance).

    In spite of this, the graphs still show modest warming. However, look at what happens if we measure trends right before or after 1998:

    It's clear that starting in 1998 gives an erroneous idea of the actual temperature trends, which is why contrarians like to do so. That is what we call cherry-picking.
  • A detailed look at climate sensitivity

    CBDunkerson at 10:50 AM on 9 October, 2010

    Karamanski #56: "Even though warming may continuing the rate of global temperature increase is steady and is not accelerating."

    Again, the data suggests that the rate IS increasing. In addition to the up-slope of the quadratic fit note that the linear trend line has been consistently below the actual results for 15 years (since 1995). With a steady trend you see the random 'noise' causing the actual results to frequently fall both above and below the linear trend. When actual results start to fall only on one side of the linear trend line it is a clear indication that the actual trend is NOT linear (or 'steady' as you suggest), but rather curving in the direction of the variance.

    "For instance, they did not predict the halt in the increase of methane concentrations over the past decade."

    The slight slowing in the rate of increase of atmospheric methane levels a few years ago was generally attributed to changes in human emissions... humans are somewhat difficult to predict with climate models - which is why they are generally run with a range of different GHG emission assumptions. That said, methane levels have resumed rising more quickly and there is some indication that this is becoming a positive climate feedback rather than primarily an issue of human emissions. See

    "Arctic sea ice predictions by climate models are 40 years behind real observations."

    The IPCC tends to be fairly conservative. Some other examples of this can be found here
    and here. In the case of Arctic sea ice extent the primary factors not taken into account seem to have been increased ice export out of the Arctic region as the ice breaks up and greater than expected 'melt from the bottom up' as ocean temperatures increase.

    "I find it diffult to think that we will have a temperature increase of 3 degrees celsius by 2100."

    It should be noted that the 3 C estimate is not just a matter of models... the positive feedbacks assumed for that figure (primarily increased atmospheric water vapor and decreased Arctic ice) are evident in direct observations of current conditions. The figure is also consistent with paleoclimate reconstructions. So... past (paleoclimate), present (observations), and future (models) analysis are consistent with the 3 C figure.
  • Global warming is accelerating the global water cycle

    archiesteel at 05:13 AM on 8 October, 2010

    @fydijkstra: "By the way, 1998 is also the year that had the highest global mean temperature, according to HadCrut. Do we see here the confirmation of the pause in global warming since 1998?"

    The fact that 1998 was exceptionally warm does not indicate a "pause" in Global Warming. To suggest as much indicates a weak understanding of statistical significance in trends.

    Even HadCRUT makes it clear the warming is still there, and didn't pause:

  • The contradictory nature of global warming skepticism

    CBDunkerson at 02:18 AM on 20 September, 2010

    Baz, so essentially...

    By carefully cherry picking the start and end points, and/or citing false values for the data, you can come up with a situation where the warming is 'only' 0.12 per decade (i.e. 1.2 C total by 2100 IF we assume no acceleration)... which you can then falsely describe as "flat"... and on that basis you can then falsely say that this is sufficient to 'disprove man made global warming'.

    Where's the heat? Gee, I dunno... hottest decade in the temperature record; 2000-2009. Second hottest; 1990-1999. Third hottest; 1980-1989. Are we seeing a pattern here? You seem to be arguing that if AGW theory is correct then the temperature would have to increase at a near constant rate... which, of course, is completely contrary to AGW theory. Of course the rate of increase will fluctuate with various other conditions... such as the current prolonged lull in solar activity.

    As to there having been "no volcanoes" since 1995... absurd on its face. Tell it to all the people who couldn't fly in Europe earlier this year because of the eruption in Iceland.

    BTW, you're also wrong about CO2 emissions being higher than ever... they actually dropped a bit the past couple of years due to the global recession.

    Finally, let's compare two of your recent statements;

    Baz #277: "BTW, I've 'ignored' no other's comments other than yours"

    When I pointed out that this was false as you'd ignored my comments in #39 and #105 (amongst others) the response was;

    Baz #290: "BTW, you didn't ask me any questions in 39. I HAVE made an effort to respond to genuine questions."

    So... you switched from having answered all COMMENTS to having made an effort to respond to QUESTIONS. Except, of course, you didn't respond to my questions in #105 either. You're falling short even when you move the goalposts.
  • The contradictory nature of global warming skepticism

    KR at 05:00 AM on 16 September, 2010

    Baz - In regards to statistical significance, you might benefit from looking at the Phil Jones says no global warming since 1995 thread. There are some useful discussions there on what timeframe is appropriate for statistical significance, and what time periods are usable for drawing conclusions.

    As headlined in a British paper early this year, Phil Jones (climatologist) stated that the warming since 1995 was not statistically significant. By this he pointed out that the statistical chance of the null hypothesis (no warming) was at 8% - it should be under 5% for the 95% confidence generally used in statistical significance tests.

    Given the noise (weather, yearly variations) in the temperature trends, 30 years is considered the appropriate period, not 15. And the global warming trend from 1980 to 2009 (just over 1 degree Fahrenheit) is statistically significant at the 99.9999 percent level.

    That is to say, given the data, there is only a 0.0001 % chance that it wasn't warming over that 30-year time frame; that the resulting data was due to a noisy but not trending signal.

    You can certainly make claims of personal belief from 10 years of data - that's up to you. However, you cannot claim scientific evidence, statistical significance, from such a short time frame. The numbers don't support it.
  • Pielke Sr and scientific equivocation: don't beat around the bush, Roger

    JMurphy at 22:58 PM on 10 September, 2010

    Looking at Dr Pielke Sr's responses here and elsewhere, it appears to me that his views on global warming are determined more by his political outlook than by any evidence-based science. How can you look at some of his assertions and not see the cherry-picking to suit whatever point he is trying to make at any particular moment ?

    For example :

    "Their has been no statistically significant warming of the upper ocean since 2003."

    Can one really determine any statistical significance using a 6-year period ? warming [which, of course, has not occurred since at least mid-2004!].

    He wrote this in 2008. Does Dr Pielke Sr still agree with this ? If so, on what does he base his assertion ?

    ...lower troposphere from, say, 2001 to the present, if anything it is slightly falling

    Why choose 2001 ? What does he think of the trend up to the most recent figures ?

    ...since about 1995, if you put a linear plot since then, there has basically been no further cooling of the stratosphere

    Again, why choose 1995 ? Why not choose 2001, which was chosen for the lower troposphere ?
    Again, what does he think of the trend up to the most recent figures ?

    ...arctic ice level so it is higher than it was this time last year,

    How can anyone assert this as if it meant anything serious, especially a scientist ? What is it supposed to mean ? Again, what does he think of the most recent figures compared to this time last year ?

    ...Antarctica, for the last number of years, actually has been increasing in its sea ice coverage.

    How many years is 'the last number of years' ? What does he believe this means ?

    ...the climate hasn’t been warming over the last number of years.

    Again, How many years is 'the last number of years' ? Is it 'since at least mid-2004', as he asserted above ? Does he still agree with that assertion ?

    There is also this from an interview he gave last year :

    the globally averaged lower atmosphere has not warmed in the last nine years (and, in fact, is cooler than it was in 1998).

    How does this assertion (using a start date of 2000, presumably) tie-in with the previous claim of 'since at least mid-2004' assertion, which he wrote the previous year ? Is this what he meant by 'the last number of years' ? And why highlight the record temperature year of 1998 ? Does he think that 2010 will continue to prove his assertion that there has been no warming 'in the last nine years' ?

    Generally, I am always disappointed when I find scientists cherry-picking and letting their personal politics determine their assertions. In fact, Dr Pielke Sr's determination to continue along this line was confirmed by his recommendation of a book by his son. No surprise that a father would recommend his son : it was the title of that book that spoke volumes to me, and highlighted what I think is the rationale behind the views of certain people. The title of that book is 'The Climate Fix: What Scientists and Politicians Won't Tell You About Global Warming'. That encapsulates neatly what so-called skeptics believe, whether they are involved with the science or just believers of a certain viewpoint : AGW is a 'fix' (or conspiracy), being used by politicians to do whatever they want to do - usually restrict our freedoms, put up everyone's taxes and enrich themselves, of course. Especially Liberal or slightly-left-of-extreme-right politicians. And by associating scientists and politicians together, they can proclaim that scientists are in on the 'fix', doing it for the politicians, and enriching themselves or controlling us all by producing results that have already been agreed in advance by some secret cabal. It would all be very funny if it wasn't so sad and serious.

    Dr Pielke Sr, you won't care what I think of you but I am disappointed that there are scientists like you who are prepared to interpret and provide partial results in ways that give your audience what they want to hear, and which, purely and simply, conform to your political viewpoint.
  • Pielke Sr and scientific equivocation: don't beat around the bush, Roger

    JMurphy at 23:16 PM on 9 September, 2010

    gpwayne wrote : "unqualified claims that global warming has not been occurring on the basis of contested ocean temperatures alone are highly misleading, and the certainty of the statement is both inappropriate and unscientific."

    To me, that seems to be the biggest criticism of Dr Pielke Sr and I think he has quite a history of cherry-picking short periods with regard to other metrics.

    For example :

    "Sea level has actually flattened since 2006"

    "Their has been no statistically significant warming of the upper ocean since 2003."

    With regard to Arctic sea ice : "Since 2008, the anomalies have actually decreased."

    These can all be seen on Dr Pielke Sr's blog (from the middle of last year).

    There is also this from 2008 :

    The focusing on global warming as the reason for any hurricane (or making it more likely to occur or become more intense) ignores that natural variations are not only more important than indicated by the AP news story, but also that the human influence involves a diverse range of first-order climate forcings, including, but not limited global warming [which, of course, has not occurred since at least mid-2004!].

    Again at his blog.

    There is also interesting information from the talk that Dr Pielke Sr gave last year to a gathering under the auspices of the George Marshall Institute, including :

    Lower Troposphere The warmest time period was during the big El Niño in 1998, but if you look at the period from, say, 2001 to the present, if anything it is slightly falling. It is certainly not rising.

    But you notice that since about 1995, if you put a linear plot since then, there has basically been no further cooling of the stratosphere.

    [ARCTIC ICE LEVEL] has recovered, so it is higher than it was this time last year, for example.

    Antarctica, for the last number of years, actually has been increasing in its sea ice cov-erage. There are some that are trying to suggest that this is also consistent with a warming planet and a warming Antarctica. I find that concept hard to grasp.

    The problem is that the climate hasn’t been warming over the last number of years.

    There certainly are changes over time which again shows that climate is variable and we can’t just talk about one single metric like the global average temperature, for example.

    Anthony Watts has written a very influential and carefully put-together report, Is the U.S. Surface Temperature Record Reliable?, which came out of a Heartland Insti-tute meeting, held a few months ago.

    What Anthony Watts has done (and we are working on a paper with him on this for publication soon) is document how many sites are well located and how many are poorly located

    Any further information on that paper ?
  • Pielke Sr and scientific equivocation: don't beat around the bush, Roger

    NETDR at 10:48 AM on 9 September, 2010

    Did anyone post that the Atmosphere was cooling at the same time that the oceans were cooling according to both the GISS and UAH satellite temperature readings.

    So the heat isn't in the oceans and it isn't in the atmosphere, where did it go ? To the Lithosphere ? I doubt it.

    I agree with Dr Pielke that the heat cannot leave the system and return. It could go from atmosphere to ocean and back but it cannot leave if Global warming is happening.

    In fact since the atmosphere warming is so slight since 1995 the claim has been made that the positive feedback heat is somehow hiding in the oceans to cause rapid warming in the future.

    BTW: I object to the term "deniers" with it's obvious connotations without specifying exactly what is being denied. I do not deny it has warmed slightly. [for example]I do deny there is a catastrophe coming in the next 100 years.
  • Is the sun causing global warming?

    kamilian at 00:55 AM on 22 August, 2010

    So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming.

    No credible science? So you're suggesting that this site isn't about credible science? Seeing as this page quite clearly states:

    The other consequence of the warming ocean is it means there is additional "warming in the pipeline". Even if CO2 emissions were to start falling now, we already face further global warming of about another half degree by the end of the 21st century (Meehl 2005).

    So even if the forcing was reduced, there'd be warming for potentially 90 years. Considering this page suggests that the temperature in the graph on this page also corresponds closely to SSTs, then the cooling trend around 1940-1950 doesn't correspond to the increasing solar activity.

    Seeing as the temperature fell or remained stable while solar activity increased between 1940 and 1960, and a reduction in CO2 now would see continued warming, it suggests that temperature doesn't directly correlate (temporally) to the forcing. It seems far more likely that the increase in solar activity of ~0.8 W/m^2 up to 1960 in that graph is the cause of recent temperature changes rather than the CO2 change since 1960 of 5.35*ln(390/317) = ~1.1 W/m^2 (i.e. they're of similar magnitude) due to the thermal inertia of the system.

    Perhaps you would also like to put things in perspective. From 1880 there's been a minimum ~0.5 W/m^2 increase in solar activity (~0.8 W/m^2 until 1960, then a decrease). In the same time there's been a change in CO2 of 5.35*ln(390/290) = ~1.6 W/m^2. According to the IPCC there was a change in CO2 between 1750 and 2005 of ~1.7 W/m^2 and a net change in anthropogenic forcing of ~1.6 W/m^2.

    How can solar variability be completely discounted, since the graph here suggests it's at least ~30 % of the change due to anthropogenic sources? How do you explain why the IPCC graph suggests ~0.1 W/m^2 due to solar irradiance when this graph suggests otherwise? Perhaps the IPCC doesn't consider it cherry picking, but ~0.1 W/m^2 doesn't show the full story even if it is an accurate delta between 1750 and 2005.

    Furthermore, what known physical properties of greenhouse gases are you referring to?

    When I think of physical properties, I think of this as an example. We see that the Stefan-Boltzman constant is considered to be known to a standard uncertainty of 4e-13 W/m^2 and relative standard uncertainty of 7e-6 (68 % confidence interval). For two standard deviations (95 % confidence interval) it would be an uncertainty of 8e-13 W/m^2 and relative uncertainty of 1.4e-5.

    I would have thought that the effect of CO2 is pretty important in climate science, Section 6.3.1 of this document says:

    IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included.

    So it used to be 4.37 W/m^2, which was revised to between 3.5 and 4.1 W/m^2, leading to the current 3.7 W/m^2, all of which are estimates as opposed to physical properties. These estimates have an uncertainty of 0.2 W/m^2 and relative uncertainty of 0.05 (with no mention of confidence interval). Interestingly, IPCC AR4 WG1 Section 2.3.1 suggests 3.7 W/m^2 +/- 10 % for a 90 % confidence interval, giving an uncertainty of 0.37 W/m^2 and relative uncertainty of 0.1, which could be considered worse than the TAR!

    I don't think they really compare as physical properties, and don't see how they can be considered to be known when they're estimated.
  • Is global warming still happening?

    thingadonta at 12:53 PM on 18 August, 2010

    "those long term trends show that the globe is still, unfortunately, warming."

    The above diagram may be true, but is slightly misleading/doesn't present the whole picture. Skeptics have pointed out that several indicators are slowing in their rate of warming, contrary to IPCCC projections.

    (Which is also why the kefuffle with Trenberth and Jones' (mis)quotes 'we cant account for lack of warming', 'no warming since 1995' etc etc has occurred-they cant account for the 'slowing rate', unless one takes into account overall ocean heat-which may just be a convenient excuse).

    If global warming 'rate' is slowing in these indicators (air T near surface, T over land, reduction in sea ice, sea surface T), this is in contradiction to IPCC projections.

    This may of course be natural variation, as often claimed, but it is more correct to state it so, and make it explicit, unlike in the diagram above: data indiactes several warming indicators are in fact slowing in the last decade or so. (Also in line with a cooling sun, also suggesting the sun is still a major factor in recent climate variations).
  • Temp record is unreliable

    Berényi Péter at 23:54 PM on 10 August, 2010

    #99 Ned at 21:31 PM on 4 August, 2010
    As a reminder, BP's figures (like the first one in his comment above) are not particularly useful as long as he continues to use simple averages of the GHCN data set.

    In a sense that's true. But it is good for getting an overview, the big picture if you like. Also, if adjustment procedures are supposed to be homogeneous over the entire GHCN, this approach tells us something about the algorithms applied, if not about the actual temperature trends themselves.

    However, with a closer look it turns out there are multiple, poorly documented adjustment strategies varying both over time and regions. Some adjustments are done to the raw dataset, some are only applied later, some only to US data, some exclusively outside the US, but even then different things are done to data in different regions and epochs.

    A gridded presentation is indeed an efficient way to smear out these features. On the other hand, it is still a good idea to have a closer look on intermediate regional and temporal scales if one is to attempt to identify some of the adjustment strategies applied.

    For example here is the history of temperature anomalies over Canada for a bit more than three decades according to three independent datasets (click on the image for a larger version).

    I have chosen Canada, because of data availability and also because this country has considerable expanses in the Arctic where most of the recent warming is supposed to happen. The three datasets used were
    1. GHCN (Global Historical Climatology Network)
    2. The National Climate Data and Information Archive of Environment Canada
    3. and Weather Underground, an independent weather portal company (a spinoff from the University of Michigan)

    The three curves have some family resemblance, but beyond that their physical content is radically different. Weather Underground shows an almost steady decline since 1989 (that is, a 0.8°C cooling), GHCN a huge warming (more than a centigrade in three decades, almost 1.27°C in five years between 1994 and 1999) while Environment Canada something in between with practically no trend since 1985.

    Up to about 1995 the three curves go together nicely. With some offset correction (which has no effect on temperature anomaly trends) they could be brought even closer. The same is true after 1998. Therefore in this particular case most of the action happened in just four years between 1995 and 1998.

    In this period the divergence is very noticeable, so the next thing to do is to have a closer look at these years in Canadian datasets and to determine the exact cause(es) of discrepancy.

    Now I do have all the data necessary to do the analysis at my fingertips. Unfortunately I do not have too much time for this job, you may have to wait a bit. Neither was it always easy to collect the data. My IP has even got banned from Weather Underground for a while because they might have noticed the work the download script had been doing. Anyway, I have no intention to publish their dataset (as long as it stays put on their website), I just use it for statistical purposes.

    The spatio-temporal coverage patterns of the three datasets are different inside Canada. Weather Underground, understandably, has an excellent recent coverage, getting sparser as we go back in time. Fortunately for some sites their archive dataset goes back to January, 1973 (e.g Churchill Falls, Newfoundland). They also use WMO station numbers (at least in Canada), which is convenient (the connection between four letter airport identifiers and WMO numbers can get obscure in some cases).

    It is just the opposite with Environment Canada. Their coverage in early times is even better, than the previous dataset's (they go back to March, 1840), but it is getting sparser as we approach the present (unfortunately their station identifiers are different from those used by either GHCN or Weather Underground).

    This tendency of station death is even more pronounced in GHCN. It is not easy to understand why. GHCN has a particularly poor recent coverage in the Canadian Arctic, although this area is supposed to be very important for verification of computational climate models (Arctic Amplification and all).

    It is funny, that even the raw map used by GISS misses a fair number of the arctic islands that belong to Canada and shows sea in their place. At the same time Arctic coverage of Environment Canada is excellent. Their data are also said to be quality controlled and of course digitized. Why can't it be fed into GHCN? Looks like a mystery (I know there used to be a war between the two countries back in 1812 when seaborne British terrorists ate the President's dinner and set the White House aflame, but I thought it was over some time ago).

    Anyway, the very practice of making adjustments to a raw dataset prior to publication is a strange one, which would be considered questionable in any other branch of science. But should adjustments be done either way, if their overall magnitude is comparable to the long term trend, anything is measured but the trend itself.

    The double adjustment to raw Canadian data also makes understandable why USHCN have got a different treat than the rest of the world. It would be pretty venturesome to meddle with US raw data directly for the US, despite the recent legislative efforts of both major parties to put an end to this preposterous situation, is still an open society, more so than most other countries of the world. Therefore it was advisable to introduce US adjustments only in v2.mean_adj, which is a unique feature, not done for the rest.

    As the US is only a tiny fraction of the globe, at first sight it does not make much sense to go into such pains. But without the 0.52°C upward adjustment of the US trend, data from there would get inconsistent with neighboring Canadian ones. What is more, it would be somewhat inconvenient to explain why the US does not have this warming thing, but still needs cap & trade.

    It is also noticeable, that the strange divergence, if global, does not increase one's confidence in computational climate models parametrized on this very dataset.
  • Confidence in climate forecasts

    chris at 06:52 AM on 5 August, 2010

    Dappledwater at 05:26 AM on 5 August, 2010

    angusmac at 02:43 AM on 5 August, 2010

    We need to be a little bit careful here. Remember that Hansen’s model was constructed and parameterized almost 30 years ago. The computational run under discussion used a 100 year control equilibration with no forcings, and simulated the earth global temperature from 1958 to 2020 according to a number of scenarios [*].

    Dappledwaters picture (Figure 2 from Hansen et al. 2006) shows that the simulation has done a good job of simulating the actual earth surface temperature through around 2005. Angusmac’s figure updates the data through 2009. The simulation and measured surface temperature data now converge a bit.

    What do we make of this? I’d say the following are relevant:

    (i) There’s no question that Hansen’s simulation B has tracked the real world temperature from 1958 through 2005 pretty well. Scenario B is a little above the real world observations. However as Hansen et al. 1988 state [**] their model is parameterized according to a climate sensitivity of 4.2 oC (equilibrium surface warming per doubling of [CO2]). Since the mid-range best climate sensitivity estimate is 3.0 oC, we’re not surprised if the model is a little “over warm”.

    (ii) Since 2005, the global temperatures haven’t risen much whereas the model has increased. So there is a divergence as indicated in angusmacs picture. However if a model of Earth temperature matches reality quite well up to 2005, the fact that it diverges somewhat during the subsequent 4 years isn’t a reason to consider the model a poor one. As Alden Griffiths discusses elsewhere on this site, short term events can easily result in temporary shifts of observables from long term trends. There’s no expectation that the Hansen model should accurately track reality since stochastic variability is differently represented in reality and in the models.

    (iii) Is there anything we might say about the period 2005-2009? Yes, it’s a period that has seen the sun drop to an anomalous extended solar minimum, and that has had a largish cooling La Nina that greatly suppressed temperatures in 2008. So we’re not surprised that temperatures haven’t risen since 2005.

    (iv) Is there anything significant about the fact that scenario B and C are rather similar right now? Not really. Scenario B is a scenario that roughly matches the extant emissions and (serendipitiously) includes a significant volcanic eruption in the 1990s (1995 in the model; 1991 Pinatubo in reality). In scenario C greenhouse emissions were “switched off” after 2000. However since the Earth surface continues to warm under a (non-supplemented) forcing for some time due to inertial elements (the oceans) of the climate system, we don’t expect scenarios B and C to differ to much for a while following 2000.

    [*] from Hansen et al. (2006)
    “Scenario A was described as ‘‘on the high side of reality,’’ because it assumed rapid exponential growth of GHGs and it included no large volcanic eruptions during the next half century. Scenario C was described as ‘‘a more drastic curtailment of emissions than has generally been imagined,’' specifically GHGs were assumed to stop increasing after 2000. Intermediate scenario B was described as ‘‘the most plausible.’’ Scenario B has continued moderate increase in the rate of GHG emissions and includes three large volcanic eruptions sprinkled through the 50-year period after 1988, one of them in the 1990s.”

    [**] from Hansen et al. (1988)
    “The equilibrium sensitivity of this model for doubledC O2 (315 ppmv - 630 ppmv) is 4.2 oC for global mean surface air temperature (Hansen et al. [1984], hereafter referred to as paper 2). This is within, but near the upper end of, the range 3 o +/- 1.5 oC estimated for climate sensitivity by National Academy of Sciences committees [Charney, 1979; Smagorinsky, 1982], where their range is a subjective estimate of the uncertainty based on climate-modeling studies and empirical evidence for climate sensitivity.”

    J. Hansen et al. (1988) Global Climate Changes as Forecast by Goddard Institute for Space Studies Three-Dimensional Model J. Geophys. Res. 93, 9341–9364

    J. Hansen et al. (2006) Global temperature change Proc. Natl. Acad. Sci. USA 103, 14288-14293
  • 10 key climate indicators all point to the same finding: global warming is unmistakable

    Arkadiusz Semczyszak at 00:04 AM on 30 July, 2010

    “So while there are many skeptics who agree that global warming is happening but question the cause ...”

    Are we really the minority?

    We only have claim to the importance of the fact that "the CO2 concentration increases humans derived from burning fossil fuels." And we have arguments.

    “Recent Changes in Phytoplankton Communities Associated with Rapid Regional Climate Change Along the Western Antarctic Peninsula”,Montes-Hugo, et al, 2009,
    “The climate of the western shelf of the Antarctic Peninsula (WAP) is undergoing a transition from a cold-dry polar-type climate to a warm-humid sub-Antarctic–type climate. Using three decades of satellite and field data, we document that ocean biological productivity, inferred from chlorophyll a concentration ( Chl a ), has significantly changed along the WAP shelf.”
    “Paleo-records show that analogous climate variations have occurred in the past 200 to 300 years, and over longer 2500-year cycles, with rapid (decadal) transitions between warm and cool phases in the WAP. In this study (~30 years), the Chl a trend evidenced in the southern subregion of the WAP presented similar characteristics to those trends detected during typical interneoglacial periods (~200 to 300 years) (ie, high phytoplankton biomass, and presumably productivity, due to less area covered by permanent sea ice).”

    That is further evidence that the current warming, then what happens to the ice, these "10 key climate indicators - to change them, is not limited to: „CO2 concentration increases derived from humans burning fossil fuels.”

    The 1,800-Year Oceanic Tidal Cycle: A Possible Cause of Rapid Climate Change
    Charles D. Keeling (!!!) and Timothy P. Whorf
    - “Variations in solar irradiance are widely believed to explain climatic change on 20,000- to 100,000-year time-scales in accordance with the Milankovitch theory of the ice ages, but there is no conclusive evidence that variable irradiance can be the cause of abrupt fluctuations in climate on time-scales as short as 1,000 years. We propose that such abrupt millennial changes, seen in ice and sedimentary core records, were produced in part by well characterized, almost periodic variations in the strength of the global oceanic tide-raising forces caused by resonances in the periodic motions of the earth and moon. A well defined 1,800-year tidal cycle is associated with gradually shifting lunar declination from one episode of maximum tidal forcing on the centennial time-scale to the next. An amplitude modulation of this cycle occurs with an average period of about 5,000 years, associated with gradually shifting separation-intervals between perihelion and syzygy at maxima of the 1,800-year cycle. We propose that strong tidal forcing causes cooling at the sea surface by increasing vertical mixing in the oceans. On the millennial time-scale, this tidal hypothesis is supported by findings, from sedimentary records of ice-rafting debris, that ocean waters cooled close to the times predicted for strong tidal forcing.”

    The origin of the 1500-year climate cycles in Holocene North-Atlantic records, Debret, 2007: “Since the first suggestion of 1500-year cycles in the advance and retreat of glaciers (Denton and Karlen, 1973), many studies have uncovered evidence of repeated climate oscillations of 2500, 1500, and 1000 years. During last glacial period, natural climate cycles of 1500 years appear to be persistent (Bond and Lotti, 1995) and remarkably regular (Mayewski et al., 1997; Rahmstorf, 2003), yet the origin of this pacing during the Holocene remains a mystery (Rahmstorf, 2003), making it one of the outstanding puzzles of climate variability.”
  • What happened to greenhouse warming during mid-century cooling?

    Roy Latham at 02:59 AM on 5 July, 2010

    The paper provides evidence that less cloud cover is responsible for a significant part of global warming, which is what skeptics have been saying. We are only talking a few percent of cloud cover to account for present global warming, although cloud cover may be only one factor.

    The proposed method for pollution causing dimming is that it provides more nucleation centers for water droplets, and fine drops reflect more energy back into space than large droplets. The energy is not destroyed. Analysis of pollution concentrations seem to be indicating that manmade pollution is too small an effect to account for the pre-1980 dimming.

    Some volcanoes put sulfates high up in the upper atmosphere, and that definitely results in cooling. Only a relatively few volcanoes get the sulfates up high enough to have the effect; Mount Pinatubo was one. There have been fewer such volcanoes in recent years. The models predicting climate crisis do not model volcano effects, although modelers are forced to discount the bad years.

    Skeptics argue that climate is complex, so that recent global warming is a product of CO2, ocean cycles, low volcano activity, cosmic ray activity, and so forth. Effects added during 1980-1995. Crisis advocates argue that nothing is going on of significance except CO2, and since nothing else was affecting climate the CO2 effects must be multiplied beyond what straight physics predicts. That's why 15 years of no warming is a problem for CO2 theory. However, it is consistent with complex causes.
  • Monckton Chronicles Part IV– Medieval Warm Period?

    chris at 03:53 AM on 13 June, 2010

    Passing Wind at 15:15 PM on 12 June, 2010

    You suggest in relation to the graphs Monckton showed as a backdrop to his assertion that ""....the Medieval Warm Period was real, was global, and was warmer than the present. That is the scientific consensus.....", that "..he was absolutely correct in using them.”

    Since at least 6 of the graphs don't support his assertion at all it's difficult to understand your approval, unless you consider that it's immaterial what one shows when asserting blatant falsehoods. Let's look at one of these in more detail.

    Monckton shows a sketch of broad climate regimes attributed both to” Dansgaard (1969)” and to “Schonweise” [sic] “(1995)”. The Dansgaard paper was written 40 years ago at a time when our understanding of past climate was poor in detail and before the major warming of the last 30-odd years that we obviously have to consider when assessing (as Monckton claims to be doing) the relationship between present temperatures and the MWP.

    However Schonwiese (1995) is rather more recent. This presumably refers to a book [Schonwiese, C.D. (1995): Klimaanderungen, Daten, Analysen, Prognosen. Springer Verlag, Berlin] which I can't access. It isn't from the single paper that Christian Schonwiese wrote in 1995 as can be easily determined by inspection:

    Schonwiese C D and Bayer D (1995) Some statistical aspects of anthropogenic and natural forced global temperature-change Atmosfera 8, 3-22

    Luckily we can look at a paper Dr. Schonwiese wrote in 1997 which contains a slightly modified version of the graph that Monckton shows (see top middle graph in Figure 2 of the article at the top of this thread). What can we conclude about Dr. Schonwiese's understanding and depiction of the relationship between current temperatures and temperatures during the MWP in 1997?

    The graph is shown in Figure 1 of:

    Schonwiese CD (1997) Anthropogenic and natural signals in climate variations Naturwissenschaften 84, 65-73

    This graph shows essentially the same sketch as depicted in Monckton’s Powerpoint slide, but extends the temperature to the present as well as predicting 100 years into the future. The MWP has a temperature max ~15.4 oC. It’s not easy to determine what the current temperature is since Schonwiese has a rapidly rising temperature squashed into the right hand side of the plot and it’s not completely obvious where the current temperature becomes the projected temperature. However current temperatures seem to be in the range ~15.7 - ~16.3 oC. Incidentally he considers that temperatures will continue to rise in the 100 years (from 1997) to around ~ 19 oC although he labels a range between 17.5 – 20.5 as uncertain (“unsicherheit”).

    In other words it’s very difficult indeed to consider that Dr. Schonwiese’s work from the mid-1990’s could be used to support the assertion that the MWP was warmer than now. Again the opposite interpretation seems warranted from Monckton’s supposed source. Likewise it would seem that Dr. Schonwiese was rather concerned in 1997 about very significant warming in the coming decades. Note that we can’t use this figure to say anything about the global nature of the MWP since it’s clear that the sketch refers to Northern hemisphere temperatures.

    If we’re not totally certain (since Dansgaards and Schonwiese’s figure copied by Monckton is obviously a sketch) we could look at Dr. Schonwiese’s more recent work. In a paper published earlier this year [*] he assess likely anthropogenic contributions to warming since 1860. The total warming is around 0.8-0.9 oC globally (1.0-1.1 oC in the NH).; Schonwiese determines that pretty much all of this (less around 0.2 oC natural contributions) is due to anthropogenic greenhouse forcing, somewhat tempered by atmospheric aerosols. If we add this temperature rise to the temperature around 1860 in the Dansgaard/Schonwiese sketch that Monckton shows, then the current temperature is around 16-16.1 oC compared to 15.4 oC at the MWP max.

    [*]Schonwiese CD, Walter A, Brinckmann S (2010) Statistical assessments of anthropogenic and natural global climate forcing. An update. Meteorologische Zeitschrift 19, 3-10.

    In other words the Dansgaard/Schonwiese graph that Monckton shows in support of his bogus assertion actually supports the conclusion that the MWP was significantly cooler than now. Now, most people might say that it’s difficult to draw major conclusion about past temperatures from a sketch. However you (Passing Wind) have asserted that Monckton is ”absolutely correct” in using this to accompany his bogus assertion about what the scientific evidence shows.
  • Monckton Chronicles Part IV– Medieval Warm Period?

    chris at 23:01 PM on 12 June, 2010

    Passing Wind at 15:15 PM on 12 June, 2010

    ”I would argue that where one knows a scientist has changed their view because it is common knowledge, then one should say so. With regard to the MWP, Monckton is claiming the IPCC wanted it to disappear, and he presents 9 slides out of a claimed 700 papers to show that it did once exist. He should have said that some of those scientist out of the 9 slides he shows have since claimed the MWP was slightly cooler than today. But he was absolutely correct in using them.”

    That’s a travesty of even the bare minimum of an ethical approach to communication of science. You’re proposing that in purporting to present the consensus view of a scientific field [*] it’s acceptable to make unsupported assertions that are completely contradictory to the scientific consensus, to cherrypick a handful of graphs of known or unknown provenance, to misrepresent the science related to these specific sets of data, and to hunt back into the old scientific literature to find bits of analyses which give the impression of supporting your assertion even when the authors of this data have subsequently reassessed their data and analyses.

    One of the problems with Monckton’s presentation is that it’s vague, and that gives you latitude to jump around from one position to another in your defense of his scientifically illiterate presentation. Monckton's claims about the IPCC and the MWP are bogus since the IPCC have always acknowledged the presence of the MWP and no one suggests that it doesn't/didn't exist. But Monckton made a rather specific assertion about the current consensus on the MWP [*] so we can address that quite specifically; let’s remind ourselves what Monckton was asserting as he showed his selection of graphs (on Figure 2 of the top article of this thread):

    ”Here are just a few papers, 8 or 9 of them, out of the papers contributed during the last 20 years by more than 700 scientists, from more than 400 institutions, in more than 40 countries establishing that the Medieval Warm Period was real, was global, and was warmer than the present. That is the scientific consensus if you do science by consensus which the UN says it does”

    Dr Abraham (and me for that matter) is judging Monckton’s (patently scientifically false) assertion that the papers “establish that the Medieval Warm Period was real, was global, and was warmer than present. That is the scientific consensus…”. Monckton shows zero evidence for the “more than 700 scientists” and supports his assertions only with this single Powerpoint slide, so that slide is what we are addressing. It’s straightforward to show that at least the bulk of the graphs don’t support his bogus assertion at all:

    ONE: We’ve already seen that the work of Huang et al (1998) and Esper and Schweingruber (1994) cannot be used to support Monckton’s assertions. Each of these groups has concluded that in their spheres of study (Huang global boreholes; Esper and Schweingruber extratropical NH and Alps) the MWP was less warm than current temperatures. Their data lends itself to a diametrically opposed conclusion to Monckton’s.

    TWO: We can eliminate Wilson et al. (1979) and Dansgaard (1969) as evidence in support of Monckton’s assertion. After all he did assert that his analysis referred to “papers contributed during that last 20 years” and these are 30 and 40 years old respectively. As Dr. Abraham states in his top article, very old papers are less likely to be reliable contributors to the “consensus” and in any case miss out much of the warming of the last 30-odd years that Monckton is specifically referring to when he makes his bogus assertion about the relationship between temperatures during the MWP and “the present”.

    THREE: Monckton cites Schonweise (1995) in support of his scientifically unjustified assertion. Note that typically he gets this wrong (it’s “Schonwiese”). More problematically it’s easy to show that Christian Schonwiese’s papers strongly support the conclusion that present temperatures are warmer than during the MWP. If I have time I’ll make a brief post on this.

    FOUR: Monckton cites Noon et al (2003) in support of his assertion. However this is problematic for reasons further than those discussed by Dr. Abraham. The first relates to the reliability of the temperature proxy since this hasn’t been calibrated against a period of measured temperature. So, for example, the proxy hasn’t captured any of the very marked warming (more than 1 oC) directly measured in the region during the last ~100 years. The second relates to the temporal period of apparent warming. This is shifted around 200 years later than the period of the MWP in the NH. Clearly this data set can’t be used to support assertions that the MWP was warmer than now, or that it was global, if by global one means “globally synchronous”.

    FIVE: Monckton cites Keigwin (1996). This data set refers specifically to a location in the Sargasso sea. If one was to address this particular data set scientifically, one would likely conclude that it was consistent with a growing consensus that the temperature variations during MWP (and to a lesser extent) during the LIA, were significantly related to ocean current and wind transport regime changes (solar driven?) that changed the distribution of global heat, with a large contribution involving “Gulf Stream” heat transport to the high Northern latitudes. It’s not surprising that temperatures in the Sargasso sea are particularly sensitive to these.

    In support of this interpretation Keigwin and Pickart (1999) have shown that if one samples historical temperatures from cored proxies in the Laurentian Fan area to the NW of the Bermuda Rise, Sargasso Sea data, that sea surface temperatures were apparently much colder during the MWP compared to the LIA, and the temperatures of the Bermuda Rise-Laurentian Fan vary in “antiphase” as current regimes change. So if Monckton were to have selected Keigwin and Pickart (1999) rather than Keigwin (1996) he would have come to the opposite conclusion.

    If 6 out of the 9 studies that Monckton uses as "eye-candy" to front his false assertion [*] don't actually support his assertion at all then it doesn't leave very much in the way of corroboration of his assertions. Hwever, we know anyway that his assertion [*] is demonstrably false, just as we know that Monckton's aim is specifically to misrepresent the science.
  • Climate Change and the Integrity of Science: a letter to Science

    scaddenp at 09:35 AM on 20 May, 2010

    Roy, "15 years of no global warming cannot be reconciled with the claim that human-produced CO2 dominates climate. The climate record is out of the 95% bounds of the models.

    I think you believe things that are not true. On the "no warming" try no warming since 1995. It seems to me that you are relying on very unreliable source. Check it yourself. Numbers easily available.

    As for out of 95% bounds of model - huh? For starters on whether it can be "reconciled" you could try Dont be fooled again. However, 15 years is not climate. 16 year trend is significant warming, but 30 year trends is what climate models predict.
  • Why are there fewer weather stations and what's the effect?

    skepticstudent at 19:05 PM on 7 May, 2010

    Ok I will respond to two different comments here, the rest are just similar in line with these two comments.
    .41 Ned and # 16 Nautilus_Mr

    You are both pretty much saying the same things as everyone else and I challenge these statements.
    First Nautilus_Mr is saying that Watt’s famous photos are red herrings and dumbing down the information.
    No! Those pictures are the crux of what is wrong with much of the information being pushed by the side of ACGW alarmists.
    On one hand you say that obviously the first will be a casual effect of weather increase but in the same breath you say that these pictures are red herrings.
    These new weather stations were placed between 1995 and the year 2000. There were guidelines which were obviously ignored in the placement of numerous sensors. I have pictures of about 30 sensors that are placed either over asphalt or lava rock, or in front of air conditioner outlets or even in the case of two pictures, within 50 feet of the exhaust of airplanes where they sit on the hot tarmac with the exhaust aimed right at the sensor. These sensors were placed at about the same time that the temperature anomalies started showing up. Also the sensors that are missing aren’t just one or two, there are 30,000 sensors that have been removed and are no longer giving temperature. This occurred roughly during the same time period between the years 1995 to 200.
    People talk about UHIE and how it doesn’t have any appreciable effect. I have lived in Southern Arizona and I know for a fact that there are more people now. A tremendous amount versus 1984 when I lived in the Tucson area and the Grand Canyon area. How can any scientist in good conscious not consider that data from an area whose paved roads, homes, automobiles, trucks bringing in supplies and goods to a vastly increased population would further increase temperatures in an already extremely hot place? I just can’t understand it. Not to mention if you look at the main USHCN sensors, I am currently looking at a 10.5 X 11 picture of it as I write this… Just look at the picture and ask yourself what is wrong with this picture. There are at least 10 cars that have parked within 15 feet of it, obviously by looking at its placing you can see with your own two eyes that they had to go passed it and then stop and cool down. Have you ever felt the heat given off by a catalytic converter in a cold town let alone one like Tucson? There is also a very large building nearby which anyone that has lived in Arizona, New Mexico, Utah or Mexico will tell you that this type of building will give off a tremendous amount of heat and is less than 50 feet away. The reason why I talk about this town and this sensor so much is it is frequently mentioned as one of the hottest growing towns in the last 25 years. Can I just be a man and lose the scientific pontification for a minute and just say an emphatic DUHHH!
    Then you throw in the 30,000 sensors that disappeared from Russian and numerous other high latitudes or high altitudes. You put all those things together and try to tell me seriously with a straight face while you look me in the eye that those are all nominal enough that you can just wipe them out with an adjustment in a proxy in a computerized model and it don’t mean anything? Seriously?
    As if all the other evidence wasn’t enough for the Jury at hand… There was a study done for UHIE effects in Barrow Alaska, one of the smallest villages in the world, in one of the coldest places in the world.
    There were several dozen temp sensors placed around the village with roughly 200 or less people depending on the birth, death, and escaping of teens to warmer more exciting climes…. And then several dozen more placed outside the “urban area”.
    Now when I say urban area, there are only a few buildings, you can only drive a full size vehicle less than three months out of the year and around 200 people. This is not a metropolis folks. It’s an Alaskan village. But still even in the middle of winter, (a very cold winter I might add) the study showed an increase in temperature in the town versus the outlying “rural” area.
    If that doesn’t make a believer out of you on UHIE I don’t know what will. But yet once again this is one of the many things that the ACGW believers either aren’t willing to talk about, don’t know about, or try to hide.
    Ned… here’s a good match for scientific reality for you. View the report about the joint study between NASA with their Satellites, and an organization called Remote sensing Systems. They took the information provided by NASA and their own oceanic buoy sensors and both Satellite and buoy information shows that even with Vulcanic offflow (which is very important because I think both sides of the equation would agree that heat rises, unless there is a new study for that now as well) the oceanic temperatures are cooler now by a considerable amount than they have been for the last 35 years since Satellites have flown around our orbit. Keep in mind, any kind of satellite data is relatively new since they have only been flying since 1975.
    If you go to their website you can view a real time chart that shows the globe with a daily updated view of all the buoys on the globe, there are a lot of them.
    This is a grid of buoys as of their daily update from about 2 weeks ago. As you can see there is quite a large amount of these sensors splattered across the globe. This mixed with science I feel can be a very good depiction of true information.
    I would challenge anyone to tell me that surface and shallow subsurface temperature sensors placed around the oceans of the globe would not be a far better even keeled relative measurement than land surface sensors that have all sorts of built in biases.
    Looking at Ocean bound sensors that tell us that temperatures for the last 20 years have been cooling globally (even though they have to deal with Volcanic effluence) are not a better picture of the global warming or cooling trends I would love to have you help me wrap my brain around that.
    Ignoring all the papers that have been written on the side of the ACGW can you still tell me that UHIE amounts to nothing?
    So yes it does matter that new sensors aren’t being placed very intelligently (or at the most polite that I can be, failed to follow the rules of best practice given to them by the people telling them what to do and where to go) Yes it does matter and no it is most certainly not a red herring when you look at a picture of a sensor less than two feet and right over the top of a very large industrial grade air conditioning outvent. Or sensors very near where the exhaust of a plane would blow for long periods of time as it warmed up before takeoff. Yes it does matter that towns have more people in them and more asphalt roads. It matters very much. also shows a grid of sea surface temperatures that are pretty much flat since the beginning of the 21st century and shows the drastic decrease of sea surface temperatures in 2008, which mimic the cold temperatures on land surface.

    If you look at the map on the link below it shows a gridded map of surface temperaatures across the US over a period of time. It points out Tuscon, AZ specifically.(Map by Steve McIntyre in 2007 of USHCN data adjusted for Time of Observation.
    Let’s also look at the facts of Amateurs who truly had nothing to gain, and people that work for an arm of the government that is spending trillions of tax payers dollars to research in the name of global warming. Who is more trustworthy here folks? Is there a scientific formula or computer model to proxy or filter out greed and corruption?
    What does this have to do with anything you might ask? It’s not politics and it’s not ad hominem, it goes to the evidence of what placing of sensors has to do with anything and why the UHIE is real and it effects the numbers beyond what you can wish away with a computer model. The timeline of all this, the disappearance of 30,000 colder clime sensors, the takeover of weather sensor monitoring and placement by United states government workers, all correlating to roughly the same time period, 1995-2000.
    How can you look me in the eye, scientist or otherwise and deny these facts and tell me that sensor placement, or UHIE has nothing to do with the presentation of those on the side of ACGW?
    Next I will bring up the incident where the Goddard institute had to eat crow and admit the fact that it didn’t do any quality control of information given to them. There was a report put out about the anomaly of the warmest snowy day in history. It talked about the anomaly of 2008 when there was more snow in Russia than there had been in a very long time. There was also a lot more snow in the Pacific Northwest and in Alaska in a very long time, yet the information given stated that it was the warmest October on record. Continued signs of global warming. Not just in the United States but also in Russia.
    What the paper didn’t state was that the person giving the Goddard institute it’s temperature data apparently for some reason decided to give the same data two months in a row, in reality instead of giving data for September and for October, they gave the same data for September two months in a row. (You have to ask yourself why the rocket scientists at NASA didn’t catch this) I have to say here that my 83 year old mother who is about as far as you can get from being a scientist has told me since I can remember, that September is typically one of the warmest months of the year and is even warmer than August usually, it’s called Indian Summer. The question begging to be asked, If my 83 year old mother who can’t even figure out how to program her VCR and watch another show at the same time understands this why didn’t Goddard?
    The best excuse they could come up with is that it is third party information that has been given to them for a long period of time and it wasn’t there fault. Isn’t part of the scientific method and the idea behind the ETHOS of writing a presentation supposed to be that you follow up on your information so no bad information ever gets past you? This isn’t to insult the scientists at Goddard in an ad hominem attack, this is to point out some very shoddy scientific writing that is supposed to support the agenda of ACGW and deny UHIE and other information pretty much drives home the importance of those two previously discussed items more than ever.
  • Common graphical tricks and the Medieval Warm Period

    Tom Dayton at 01:12 AM on 2 May, 2010

    alphaomega, the breadth of your comments makes me think you would benefit from and enjoy reading the overview by cce titled The Global Warming Debate. I suggest you read that before diving into the details that are in the following links.

    alphaomega wrote the following italicized and quoted things. For each, I've responded by linking to the appropriate post here on the Skeptical Science site. alphaomega, if you want to discuss any of those topics, those threads are the appropriate places to do so. Not on this thread, where your comments likely will be deleted for being off topic.

    "Dr Jones admitted in a recent BBC interview that there has been a slight cooling since 2002 and statically not significant warming since 1995." See Phil Jones says no global warming since 1995. Also see It’s cooling.

    "So we are on a current temperature downturn and the sun is still quiet. Is it actually possible that we might return to Maunder minimum terrritory instead?" See We’re heading into an ice age.

    "I do not think that AGW supporters or sceptics really know what will happen next to global temperatures." See Models are unreliable.

    "There may be a week warming signal caused by CO2 but natural variations in climate have the ability to overpower such a signal." See Models are unreliable. Also see CO2 is not the only driver of climate. And then CO2 effect is weak.

    "It is worth while reading the recent interview with Dr. Fred Goldbereg." (This one is not a post on Skeptical Science.) Goldberg is not a climatologist. His expertise is in welding.
  • Common graphical tricks and the Medieval Warm Period

    alphaomega at 00:01 AM on 2 May, 2010

    SNRatio wrote 30 April
    "With ca 0.15 degC warming/decade, it will just take a few decades for us to leave MWP territory altogether."
    Dr Jones admitted in a recent BBC interview that there has been a slight cooling since 2002 and statically not significant warming since 1995 (I seem to recall). So we are on a current temperature downturn and the sun is still quiet. Is it actually possible that we might return to Maunder minimum terrritory instead? As an interested retired businessman I read both sides of the arguments and frankly I do not think that AGW supporters or sceptics really know what will happen next to global temperatures. I must admit I tend to lean towards the views held by such individuals as Dr Roy Spencer and Professor Lindzen that there may be a week warming signal caused by CO2 but natural variations in climate have the ability to overpower such a signal. For those believing that CO2 has this strong influence on global temperatures it is worth while reading the recent interview with Dr. Fred Goldbereg in People's Daily.
    Frankly there seems to be a long way to go before the climate science community know enough to exhort us to pull up the wallet and deliver billions of dollars to "saving the World". Just think of the AGW understanding of the behaviour of clouds and the lack of modelling of this behaviour in current climate models.
  • Has Arctic sea ice returned to normal?

    sailrick at 03:59 AM on 26 April, 2010

    HumanityRules #18

    And the upshot of what Alexandre explains in #19 is that amateur skeptics, Republican politicians and right wing media take what people like Watts say, and turn it into another global warming skeptic/denier meme, which then becomes more proof to them that AGW is hogwash. It then is a new "proof" in their littany of arguments, which get repeated endlessly in the skeptic echo chamber.

    An example of this are the claims in Febuary that global warming is over because a big part of the U.S. got a lot of snow. Actually one of the snowstorms that hit Washington DC happened on the warmest Febuary 6th on record, globally that is. But this nonsense was repeated in every right wing media outlet, the blogosphere and by Republican polticians. Donald Trump even said Al Gore's Nobel Prize should be taken away because this was proof against AGW. It was a record warm winter.

    Another example is the fallacious claim that IPCC scientist Phil Jones said there has been no warming since 1995. He never said that. But it is now another proof for skeptics,- another phony argument in their littany.
    And Watts feeds and encourages this nonsense.
    And so it goes.
  • The 5 characteristics of scientific denialism

    Ned at 23:51 PM on 19 March, 2010

    gallopingcamel writes:

    Take a look at post (#102). Canada is the largest country in the world. Can you justify eliminating all but 44 of that country's weather stations?

    Canada is not the largest country in the world. Temperature anomalies are spatially correlated over large areas, and 44 stations are enough to cover the country. And neither NASA nor NOAA are "eliminating" weather stations -- they use the data that are provided to GHCN by participating national meteorological programs in other countries, and in some cases those stations are dropped by their home countries or there are delays in reporting. For example, with Canada, there are many more stations with data currently through 2008 which presumably will be providing updated data at some point. If you have a problem with this, complain to Canada, not to NASA or NOAA.

    Continuing, gallopingcamel writes: You can put all the statisticians in the world end to end but they will still not reach agreement. Your claim may be correct but the only way to prove it would require comparing the full data sets with the truncated sets.

    This is exactly what Tamino and others have done.

    More to the point, there are good a priori reasons to believe that dropouts of high-latitude, rural, and high-altitude stations would if anything artificially decrease the warming trend, not increase it. Since these areas are warming faster than the globe as a whole, when they drop out it would tend to decrease the overall trend (if the gridding methods weren't sufficiently robust to handle the dropouts).

    So, it was highly irresponsible of Watts, D'Aleo, etc. to accuse NOAA and NASA of "dropping stations" to fraudulently increase the warming trend. They made those accusations without ever testing them. Now their claims have been tested by different people using different methods, and have been found to be false.

    At this point, if you want to claim that there IS an artificial warming trend introduced by dropping the stations that are warming fastest, you need to prove that. All the evidence is against you.

    Moving on, to the next point: The satellites do not show warming at least in the last 12 years, as noted by D'Aleo & Watts.

    That's a very interesting claim. Let's look at all 10-year, 11-year, 12-year, etc. trends in both the UAH and RSS temperature series.

    In the UAH record, trends running through last month and starting in March of the following years are positive:

    2000, 1999, 1998, 1997, 1996, 1995, 1994, 1993, 1992, 1991, 1990, 1989, 1988, 1987, 1986, 1985, 1984, 1983, 1982, 1981, 1980, 1979

    UAH trends starting in the following years are negative:


    Well, let's look at the RSS record. Again, trends starting in March of the following years are positive:

    2000, 1999, 1997, 1996, 1995, 1994, 1993, 1992, 1991, 1990, 1989, 1988, 1987, 1986, 1985, 1984, 1983, 1982, 1981, 1980, 1979

    And RSS trends starting in the following years are negative:


    It's interesting that your choice of "twelve years" just happens to be the only period where either one of the satellite records shows a negative trend, that it just happens to start with the largest El Nino on record, and that even so only one of the two records shows a negative trend from that year.

    Continuing: The ground station data is diverging from the satellite data. Check John Cristy at UAH.

    Actually there's very little divergence between the two, and in the past disagreements between the satellite and surface records have turned out to be due to errors in the methods used to process the satellite data. Thus, over time, the satellite records have progressively become closer to the surface record.

    Still continuing: Sea Surface Temperatures (SSTs) are very high but are currently falling.

    Those data aren't SSTs! They're the same MSU lower-troposphere data, just disaggregated into different spatial regions (northern vs southern hemisphere, land vs ocean, tropics vs extratropics vs poles, etc.)

    Actual SST data are available here, or see Kelly O'Day's excellent graphs and scripts here.

    And there's no very meaningful sense in which "sea surface temperatures are falling" is true. You can only get a negative trend if you cherry-pick a length of 5-9 years. Trends of 1, 2, 3, or 4 years, or of any number of years greater than 9, are all positive.


    So ... this all leads to the question of why people employ such weak, wrong, or misleading arguments. If there were really good, convincing arguments to support the "skeptic" position, presumably there wouldn't be a need for the kinds of cherry-picking and factually questionable claims we see in this thread, nor for papers like McLean 2009, Lindzen & Choi, or that embarrassingly wrong Chylek one (link, link). Or E.G. Beck's physically impossible claims about chemical CO2 measurements being representative of actual global CO2 concentrations.

    Unfortunately, it takes a lot more time and effort to track down and refute these kinds of incorrect claims than it takes to make them in the first place.
  • Hurricanes aren't linked to global warming

    oracle2world at 12:53 PM on 8 March, 2010

    Glad the consensus has determined hurricane frequency should be retired to the ash heap of arguments. So how did this one slip through the consensus?

    Global warming is causing more frequent hurricanes in the North Atlantic and Gulf of Mexico, according to a study from the National Center for Atmospheric Research.

    The increased frequency of tropical cyclones ``is largely a response'' to a 1 degree Celsius rise in sea water temperatures since 1905 that was caused by greenhouse gases, the study found. Since 1995, the North Atlantic has experienced an average of 15 tropical storms a year, of which eight became strong enough to be called hurricanes. That compares with 10 tropical storms and five hurricanes per year from 1930 to 1994, the report says.

    ``There is an 80 percent chance that the majority of the current increases have been impacted by global warming,'' said Greg Holland, director of the research center in Boulder, Colorado, and co-author of the study. ``The bad news is that we've gone up in numbers overall, and in the proportion of major hurricanes as well.''

  • Did Phil Jones really say global warming ended in 1995?

    jibal at 18:50 PM on 7 March, 2010

    "Thus, scientifically, a trend that is not statistically significant DOES NOT EXIST, and must be treated as ZERO for the purposes of valid science."

    This is quite wrong. First, where did you get your 95% confidence level that the value is zero? Second, you can always find a sample size small enough that there's no statistically significant trend. If those counted as zero, we could discount any trend. The fact is, there's a statistically significant trend going back further than 1995, and the data since 1995 is consistent with it, and everything else we know indicates that it will continue.

    "the observed results are in conflict with the predictions of the computer models"

    What makes you think so? It certainly isn't true.

    "Since we have no experimental (i.e., scientific) data whatsoever to support the idea of man-made global warming"

    This is quite wrong. First, evidence doesn't cease to exist simply because it doesn't reach a 95% confidence level -- you're using a very odd and erroneous equivalence chain: "statistically significant" = "scientific" = "experimental". Second, not only are you ignoring the evidence mentioned in this very article of statistically significant warming of the oceans, you are ignoring large amounts of other data, such as NASA's examination of 29,000 indicators such as insect migrations, 90% of which support global warming, and the greenhouse physics, which counts as evidence in a proper epistemology.

    "First, the significance of Jones statement is that you cannot, scientificly, make the conclusion that there has been heating from 95-2009. That is scientific fact. This is in direct conflict with the fact that CO2 rates have continued to rise in that same time frame."

    This is a conceptual confusion that is similar to Jon's. First, you can reach that conclusion, just not by restricting yourself to the 95-2009 temperature data. Second, the inability to reach a conclusion does not in any way conflict with a prediction from a model -- for there to be a conflict, you would have to be able to conclude that the prediction is false.
  • What would happen if the sun fell to Maunder Minimum levels?

    Berényi Péter at 23:26 PM on 21 February, 2010

    #0 Posted by John Cook at 14:14 PM
    "it's helpful to compare the radiative forcing from a cooling sun to the radiative forcing from anthropogenic greenhouse gases"

    No, it is not. The very concept of "forcing" is flawed. Different kinds of "forcings" act on different parts of the climate system, so they are NOT interchangeable (even if they happen to have the same number as expressed in W/m2). CO2 makes stratosphere colder, increased solar activity (20% more UV) makes it hot. Forget about forcing as a unified concept, please.

    Also, it does not make much sense to use models to predict the long term effect of some input variable if those very models are proven lacking in postdiction.

    Also, recent "global warming" is a myth. To illustrate this proposition, consider the following graph:

    I have pulled global land surface data from

    and did some rather obvious things to it. Anyone can replicate.

    1. selected northern hemisphere stations (82% of all)
    2. considered temperature data for each month separately
    3. used only uninterrupted series at least 20 years long, with no data missing
    4. computed least square linear fit for all such 20 years interval
    5. assigned slope to mid-year of 20 years run
    6. averaged slopes for each (year;month) pair over set of stations
    7. integrated slopes backwards in time, getting temperature anomalies relative to present


    1. No warming for summer since mid thirties of last century. In fact, there is a 0.2°C/century cooling trend.
    2. No warming for July. In this case the cooling is 0.6°C/century.
    3. Springtime warming stopped in mid eighties
    4. Only winters are getting consistently warmer, even this trend is flatting out recently (since 1995)
    5. Otherwise annually averaged temperature anomaly trend looks like advertised

    The findings are robust.

    1. Have not made any adjustment for UHI (Urban Heat Island) effect. Warming is overestimated.
    2. Gregorian calendar effect is not corrected for. Since 1900 spring equinox is moving to ever earlier dates which introduces a spurious springtime warming trend. It will be reset only in year 2100 with no 29 February in that year.

    If anything, northern hemisphere climate is getting milder during last century, winters less cold, summers cooler. Exactly the pattern leading to long term ice sheet buildup, new glacial period coming.

    GHCN data go back to mid eighteenth century. It is not shown on graph (more cranky, wider margins of error), but looks like winters were even colder back then (up to 3°C) while there is no trend in summer temperatures. Little ice age was not uniformly colder, perhaps. At he end of 1820s summer temperatures were just as warm as they are today, winters much colder.

    How do models replicate this pattern for reduced solar activity?
  • Did Phil Jones really say global warming ended in 1995?

    Dikran Marsupial at 21:08 PM on 18 February, 2010

    One last comment on statistical significance, a more frequentist colleague kindly let me borrow his copy of "Statistical Inference" by Garthwaite, Joliffe and Jones (ISBN 0-13-847260-2), which says on page 72:

    "A related point is that rejection of H0 [the null hypothesis] implies a degree of disbelief in H0, but 'acceptance' of H0 simply means that there is little evidence against H0 and does not rule out other hypotheses. 'Failure to reject' is a better term than 'acceptance'"

    Of course if you cherry pick the start date then the hypothesis test is invalid in the first place as you have already looked at the data to select a period where the data don't supply sufficient evidence to reject the null hypothesis. Most of the "global cooling since X" or "lack of warming since X" are based on such cherry picking, for instance X is often 1998 or 2002, but not 2000. The reason why is fairly obvious. I suspect that 1995 was chosen as it is the earliest start date for which there is insufficient evidence to reject the null hypothesis; in which case it is in the same category.

    Phil Jones should be applauded for giving a straight scientific answer to the question without a trace of spin; that was left to the journalists to supply ;o)
  • Did Phil Jones really say global warming ended in 1995?

    oracle2world at 01:36 AM on 17 February, 2010

    Insofar as you can fit something into a headline, the text "there has been no global warming since 1995" is accurate.

    Now you can delve into the weeds about significance levels, time periods, datasets, overall trends, caveats, blah, blah, blah ... but the text speaks for itself:

    BBC: Do you agree that from 1995 to the present there has been no statistically-significant global warming

    Phil Jones: Yes

    Now if you want to start adding caveats to ALL global warming headlines ... that would be fine. Like the IPCC in its 2007 report said: "Eleven of the last 12 years rank among the 12 hottest years on record (since 1850, when sufficient worldwide temperature measurements began)."

    That last parenthetical statement seems to go by the wayside a lot. And maybe a mention of the Medieval Warm Period, and the Holocene maximum would be helpful. And satellite temps versus ground records that omit quite a bit of the earth's surface.

    Somehow the IPCC infactuation with 12 years of data was important and significant ... but the same years found to be not statistically significant don't really mean much of anything now.

    Any questions?
  • Did Phil Jones really say global warming ended in 1995?

    jasonk at 13:39 PM on 16 February, 2010

    B - Do you agree that from 1995 to the present there has been no statistically-significant global warming

    Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

    C - Do you agree that from January 2002 to the present there has been statistically significant global cooling?

    No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant.

    in (B) - is positive for an upward temp increase and there is 'almost' statistical significance with 1995 to 2009. a +0.12 up trend.

    in (C) - the 2002 to present shows a -0.12 down trend...but is not statistically significant because it is a shorter time frame.

    now, i am not a mathematician but i think if you add +0.12 with -0.12 the answer would be zero. no net gain or net loss...exactly zero.

    thus, how can things be warming +0.12 per decade and then cooling -0.12 per decade be interpreted as temperature gain?

    remember that:

    E - How confident are you that warming has taken place and that humans are mainly responsible?

    I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity.

    remember that 100% confident is still a 100% opinion. there is evidence that smoking can cause cancer but it is not 100% of time. is smoking good for any body? absolutely not. this is just an example that NOTHING in science is 100%. to say so is 100% subjective opinion.
  • It hasn't warmed since 1998

    VinceOZ at 17:17 PM on 14 February, 2010

    How does this jive with what Phil Jones is saying now that there has been no warming since 1995.

    Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995

    How can it be both?
  • ACRIM vs PMOD, the rematch

    clayco at 23:21 PM on 5 November, 2009

    @ Peter Pan

    "Benestad and Schmidt apparently do not know that since 1978 Lean 1995 as well as Lean 2000 do not differ significantly from PMOD because PMOD was build (by altering the published TSI satellite data) by using Lean 1995 and Lean 2000 as guides. Moreover, we also merge the Lean data with ACRIM since 1978 to obtain an alternative scenario, as it is evident in all our papers. The discontinuity problem addressed by Benestad and Schmidt in merging two independent sequences (Lean’s proxy model and the ACRIM) is not an issue because it is not possible to avoid it given the fact that there are no TSI satellite data before 1978."

    Nicola Scafetta
  • Climate time lag

    chris at 03:03 AM on 20 July, 2009

    re #124

    shawnet, Kirkby simply isn't a good guide for reliable understanding of these issue as we've seen already. I used the reconstruction of Judith Lean:

    Y.-M. Wang, J. L. Lean and N. R. Sheeley, Jr. Modeling the Sun's Magnetic Field and Irradiance since 1713 Astrophysical J. 625 522-538

    Lean, J. L., and D. H. Rind (2008), How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006, Geophys. Res. Lett., 35, L18701

    Here's the sentence on page 6 of Kirkby which you have used to make your calculation:

    "The increase in irradiance amounts to less than 0.5 W/m^2, which corresponds to about 0.08 W/m^2 at the top of the atmosphere, globally averaged (Fig. 5). Assuming a climate sensitivity of 0.7 K/W/m^2, this would contribute less than 0.06C of the estimated 0.6 C mean global warming between the Maunder Minimum and the middle of last century, before significant anthropogenic contributions could be involved."

    Those two sentences are packed with inaccuracies:

    [ONE] the data in his "Fig 5" shows two reconstructions of Lean (1995 and 2002). However the reference to the Lean 2002 data refers to a paper (his ref 6) in which Lean only analyzes the solar irradiance back to 1840.

    [TWO] the data in his Figure 5 assigned to Lean 2002, looks more like a solar irradiance reconstruction that Lean published a few years later in 2005 in which she and her collaborators explicitly considered irradiance changes since the Maunder Minimum (it's the one I used):

    Y.-M. Wang, J. L. Lean and N. R. Sheeley, Jr. Modeling the Sun's Magnetic Field and Irradiance since 1713 Astrophysical J. 625 522-538

    Lean's analysis gives a cycle-average reduction in the total solar irradiance at the time of the Maunder Minimum of ~ 1 W/m^2 (rather than Kirkby's "…less than 0.5 W/m^2).

    1 W/m^2 gives a temperature change of 1 * 0.25 (geometry)* 0.7 (albedo)* 0.8 (sensitivity) or 0.14 oC. (see point [FOUR] for a bit more on this analysis).

    [THREE] We've already seen that Kirkby's statement about "…. the middle of last century, before significant anthropogenic contributions could be involved." is entirely bogus. The anthropogenic contribution to surface temperature results from a pre-"middle of last century" change in atmospheric CO2 from 280 ppm (pre-industrial) to 310 ppm (in 1940). This gives near 0.44 oC of warming at equilibrium within a climate sensitivity of 3 oC.

    [FOUR] Note that the ~ 1 W/m^2 of Wang et al. (2005) is a general interpretation from two analyses using slightly different models that Wang et al made. One analysis gives a TSI cycle-averaged TSI change at the Maunder Minimum of 1.0 W/m^2; the other (containing a secular varying ephemeral region background) gives a change of 1.4 W/m^2. 1.4 W/m^2 gives almost exactly 0.2 oC temperature contribution to reduced surface temperature at the Maunder Minimum from irradiance variation using our parameters..

    [FIVE] Again there are several uncertainties. We've already seen that the MWP and the LIA are predominantly defined in the N. hemisphere and we've used the paleoreconstruction having the largest variation (Moberg et al. (2005)). The atmospheric/ocean current changes that seem to be involved in MWP/LIA N hemisphere temperaturevariation (see my post just above) likely involve large changes in heat transfer to the high Northern latitudes, and the volcanic and solar influences on these might be amplified somewhat by albedo effects from slow Arctic sea ice regression/expansion over the long time scales involved. So the climate sensitivity might be a tad larger than the 0.8 W/m^2 over the very long timescales encompassing MWP/LIA temperature variation..
  • Models are unreliable

    chris at 09:29 AM on 25 November, 2008

    Re #69 Dan

    O.K., so you've finally come round to the truism that a downtrend in temperature is not proof that a net positive feedback doesn't exist, after all. So everyone else but you wasn't wrong! Your bad indeed.

    But we got there in the end...

    Your second paragraph is illogical. We all know that the Earth's equilibrium temperature response has a logarithmic relationship to the atmospheric CO2 concentration. Arrhenius had worked that out already over 100 years ago.

    Your third and fourth paragraphs are nonsense too. Why go to a non-science magazine created with the intention (as the Editor admits) of misrepresenting the science on power industry-related matters? We've already seen (see posts #54 and #58) that "articles" in that magazine on climate-related matters are dodgy.

    Not surprisingly, the author of that article has got it wrong. There are lots of errors:

    (i) absorption of EM radiation doesn't "take place close to the surface". Photons can travel vast distances before being "absorbed". It depends on the absorbtivity/transmisivity of the medium through which the photons pass.

    (ii) If one considers longwave IR emitted from the Earth's surface, the wavelength/energy of the emitted wavelength has to be considered, since the absorption coefficient (k) is inversely related to the wavelength of the absorption band. The transmisivity, t, (absorbtivity = 1-transmisivity) of a column of air =

    t = e^(-k*p*l)

    where k is the absorption coefficient, p is the partial pressure and l is the path length.

    since the absorption coefficients for the absorption bands of the greenhouse gases are known[1], we can calculate the pathlength required to effectively absorb all of the radiation (at that energy/wavelength).

    For 99% absorption, the pathlength of the 4-5 micron absorption band of CO2 is 625 metres at current atmospheric CO2 concentrations

    and for the ~14-20 micron absorption band, CO2 at 385 ppm is still unsaturated at 7,800 metres of altitude.

    likewise for the 12-20 micron infrared absorption band of water at 0.4%, water vapour is still absorbing at 1,700 metres.

    (iii) in other words at current atmospheric greenhouse gas concentrations, the absorption bands aren't saturated, and enhancement of the concentration of greenhouse gases, particularly at higher altitudes [see (iv)], is effective in trapping more of the longwave IR emitted from the Earth's surface.

    (iv) In any case, the altitude of absorption of IR emitted from the Earth’s surface isn’t that important. A key element of the greenhouse effect is the altitude of emission of longwave IR into space. This has to happen for radiative balance between incoming radiation and outward radiation. You’ve actually given a clue to an important consideration unwittingly in the very first statement of your post:

    [Dan “bad boy” Pangbourn: “Radiated energy (from all surfaces, including earths) varies as the fourth power of absolute temperature”]

    Exactly so. As greenhouse gases are added to the Earth’s atmosphere, the radiation of IR into space is suppressed at any altitude (especially altitudes far from the Earth’s surface). So the radiation emitted to space from (say) 5 km is suppressed by enhanced CO2 concentrations, and so the altitude of mean radiation to space is increased. Since an increased altitude in the troposphere is at a lower temperature, the efficiency of radiation to space is decreased (as you said yourself). What’s the effect of this? The troposphere must warm in order to restore radiative balance. Since the surface and troposphere are strongly coupled, the warming of the troposphere is transmitted to the earth’s surface (and vice versa) [2].

    (v) The article in the anti-science journal that you linked to makes three more errors that relate to ignoring real world measurements. These are:

    (i) on page 1044 your ill-informed author states:

    “It would be expected that more CO2 would have a greater effect on atmospheric warming at higher altitudes, but that seems not to be occurring in spite of the predictions of most GCMs”.

    But as we’ve seen already on this thread, the tropsopheric warming is quite consistent with GCMs (see my posts #60 and #66, where this exact issue is addressed).

    (ii) on page 1045 your ill-informed author states:

    “The GCMs take feedbacks into account, such as the supposed positive feedback from extra warming caused by the radiation by extra water vapour”.

    Yes, exactly. In line with the enhanced tropsopheric warming caused by enhanced [CO2], the troposphere is accumulating extra water vapour rather in line with predictions [3-7]. According to your ill-informed author this shouldn’t be happening since adding extra greenhouse gases isn’t (according to him) supposed to make the troposphere warmer!

    (iii) and overall your ill-informed author neglects to state that we can measure in the real world, not only the longwave radiation transmitted down to the Earth’s surface from the troposphere (which shouldn't be happening according to your ill-informed author), but the enhancement of this radiation due to the enhanced greenhouse gas concentrations of the last 30 years (which also shouldn't be happening according to yuor ill-informed author), or the reduction in this radiation outwards to space [8-12]

    [1] this has been known for decades. See e.g RM Goody and GD Robinson (1951) Quart. J. Roy. Meteor. Soc. 77, 153

    [2] Shine, KP (1995) Spectrochimica Acta A 51, 1393-4.

    [3] Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253

    [4] Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening. Science 310, 841-844.

    [5] Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110

    [6] Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912

    [7] Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback. J. Climate 21, 3282-3289

    [8] Harries JE et al (2001) Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997. Nature 410, 335-337.

    [9] Worden HM et al. (2008) Satellite measurements of the clear-sky greenhouse effect from tropospheric ozone. Nature Geoscience 1, 305-8.

    [10] Philipona R et al (2004) Radiative forcing - measured at Earth's surface corroborate the increasing greenhouse effect. Geophys. Res. Lett. 31, art # L03202.

    [11] Wild M et al. (2008) Decadal changes in surface radiative fluxes and their role in global climate change Adv. Global Change Res. 33 , 155-167.

    [12] Philipona R et al (2005) Anthropogenic greenhouse forcing and strong water vapor feedback increase temperature in Europe Geophys. Res. Lett. 32, art # L19809.

    etc. etc. etc. etc……
  • Arctic sea ice melt - natural or man-made?

    Quietman at 15:13 PM on 25 June, 2008

    chris at 01:33 AM on 19 June 2008 (#76)
    "re #75: That's a tad dishonest Quietman"

    Re: (ii) "solar brightening from lack of aerosols". Nope. The atmospheric aerosol load has increased rather significantly since the 1960's. Thus enhanced Arctic sea ice melt has increased despite the overall decreased solar irradiation reaching the surface. Rather than "solar brightening" we've actually had a bit of "solar dimming".
    This is consistent with the paper that you cited (Stjern et al (2008); urled below[***], in which solar irradiation reaching the surface is averaged over 11 high Northern latitude stations as an indication of "dimming"/"brightening".

    IN Global dimming and global brightening - an analysis of surface radiation and cloud cover data in northern Europe BY Camilla W. Stjern1,2 , Jón Egill Kristjánsson1 and Aksel Walløe Hansen3 IT CLEARLY STATES IN QUITE PLAIN ENGLISH THE FOLLOWING:
    "In the more recent decades, most of our stations show a turn to brightening, which agrees with the new global trend described by Wild et al.(2005)."
    "While Stanhill (1995) reported of widespread dimming in the Arctic up to the mid-1990s, the present study shows a turn to brightening also here."

    We are not talking about 1995 - this is about an event in summer 2007. That is what I mean when I say something is dated. Things have changed in the last few years.

    "Using NCEP reanalysis data that span four and a half solar cycles, we have obtained the spatial pattern over the globe which best separates the solar-max years from the solar-min years, and established that this coherent global pattern is statistically significant using a Monte-Carlo test. The pattern shows a global warming of the Earth’s surface of about 0.2 °K, with larger warming over the polar regions than over the tropics, and larger over continents than over the oceans. It is also established that the global warming of the surface is related to the 11-year solar cycle, in particular to its TSI, at over 95% confidence level."
    From the Conclusion:
    Solar-Cycle Warming at the Earth’s Surface and an Observational Determination of Climate Sensitivity.
    By Ka-Kit Tung and Charles D. Camp

    This is compared (equated) EQUIVALENT TO CO2 MODELING - NOT CAUSED BY CO2. THIS ALSO IS PLAIN ENGLISH. You can not expect someone to reply to arguments based on interpretations of papers that only support their own view rather than the authors conclusions.
  • Arctic sea ice melt - natural or man-made?

    chris at 19:49 PM on 12 June, 2008

    Quietman, re Fairbridge and his "hypothesis".

    I was surprised to read in your post #17, the comment:

    "BTW - Thanks for the 2005_Hansen_et. al. link. A little dated but interesting.

    No problem, btw! However I'm surprised you consider a 3 year old paper "a little dated".

    Since I didn't know of Fairbridge's theories before yesterday I had a look for his scientific publications in the database.

    I can't find any scientific paper by Fairbridge in the last 10 years on the subject of solar influences on climate. So everything by Fairbridge is "a little dated" (certainly so in relation to Hansen's paper published in 2005!)

    Fairbridge published a brief report in 1995 that seems related to this topic:

    Fairbridge RW, Haubold HJ, Windelius G (1995) "Potential of interplanetary torques and solar modulation for triggering terrestrial atmospheric and lithospheric events" Earth Moon and Planets 70 179-181.

    but clearly a "hypothesis" can't be fully expounded in 3 pages, and this brief paper has been cited only once in the last 13 years, and clearly hasn't made any impact in the field.

    His next "most recent" paper that relates to this subject seems to be:

    Shirley JH, Sperber KR, Fairbridge RW (1990) Suns inertial motion and luminosity; Solar Physics 127, 379-392. (18 years old; 5 citations in 18 years).

    ...and so everything by Fairbridge seems "a little dated".

    The article that you linked to by Mackey isn't a scientific paper. It's a eulogy of Fairbridge by some statistician who hasn't published any science on climate change, and who uses his article to pursue the political argument that we shouldn't do anything about the problem of global warming, but should just carry on, let things take their course, and "adapt" ("Adaptive efficiency is the key"!).

    I would like to see the relevant articles by Fairbridge himself in which his "hypothesis" is expounded. Can you cite these? Let Fairbridge's work speak for itself!

    I would also like to see a description from you of the mechanisms by which the "hypothesis" of Fairbridge explains the marked attenuation of Arctic sea ice since the 1960's, and the massive excess attenuation of sea ice in the summer of 2007, and so on.

    After all, it's not very scientific to refer to some unspecified "hypothesis" as a "catch-all" explanation of everything climate-related (you said in post #13: "Thus far the cycles of the solar system's gravitational forcing has been the best explanation to date for climate change"), without explaining what this "hypothesis" is, and illustrating specifically how it pertains to the issue at hand (i.e. the attenuation of Arctic summer sea ice).
  • Arctic sea ice melt - natural or man-made?

    chris at 07:33 AM on 12 June, 2008

    Quietman, you're wandering way away from the subject of this thread which is the massive attenuation of Arctic sea ice during the summer of 2007.

    Straightforward scientific analysis provides a self-consistent interpretation in terms of global warming resulting from enhancement of the Earth's greenhouse effect through massive greenhouse gas emissions (this has been the cause of the relentless attenuation of Arctic summer sea ice since the 1960's - see urls in my posts above), together with weather conditions (reduced cloudiness and increased solar LW downwelling) that are normally rather neutral in their effects on Arctic sea ice extent, but under conditions of greatly denuded sea ice, result in rather significant melting of greatly thinned ice together with strong warming albedo feedbacks (see the top post by John Cook, the article by Kay et al (2008) that John Cook links to and which we've both discussed, and my post #12).

    You're hinting at other things without showing us any evidence for these.

    For example:

    (i) in response to my statement:

    Chris: "However, volcanic activity in general results in transient cooling of the Earth's surface temperature"

    you say: Quietman: "No. That should be:
    Volcanic ERUPTIONS in general result in transient cooling from particulates but may be balanced by GHGs from the eruption (or not, depending on the nature of the eruption)."

    But that makes no sense at all. After all if we look at the entire high resolution atmospheric CO2 record of the last 2000 years [***] we can see that atmospheric CO2 concentrations haven't varied by more than a few ppm around a value of 278 ppm in the period before the mid 19th century. So whereas the particulates from volcanic eruptions might in theory be "balanced by GHG's from the eruption", in practice during at least the last 2000 years, this hasn't been the case. Thus all volcanic eruptions of interest in the topic of this thread have resulted in cooling due to atmospheric aerosols. That's also rather clear from direct analysis of the forcings from volcanic eruptions of the 20th century [*****]

    [***]Meure CM et al (2006) Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP Geophys. Res. Lett. 33 L14810

    [*****] Hansen et. al. (2005): Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435 (see Figure 1).

    The other problem with your assertion about "GHG's from the eruption" is that you've already asserted elsewhere that you don't believe in "CO2-induced AGW" (e.g. in post #9 on this thread). So what are these "GHG's from the eruption" that "balance" "transient cooling from particulates"?

    Presumably not CO2. After all if the 65 ppm of atmosphere CO2 added to the atmosphere by mankinds emissions hasn't contributed to global warming in your worldview, how can 0.01-0.5 ppm released in a volcanic eruption (that's about the amount released during individual volcanic eruptions of the last around 2000 years) "balance" ""transient cooling from particulates"?

    Likewise, you suggest that Dr Fairbridge's "hypothesis" allows you to "expect the strong La Nina" "because 2 + 2 usually equals 4". I have no idea what you mean by that. It doesn't seem very scientific at all. However you seem to be insinuating that Fairbridge's "hypothesis" has predictive value for La Nina's (and El Nino's?).

    Here's a list of the La Nina years in the period 1872 - 2000. I've taken these from Ross Cooper-Johnston's book "El Nino" (Hodder and Stoughton 2000; page xii).

    Please indicate either:

    (i) the scientific paper in which Fairbridge demonstrates an analysis that allows this series to be understood in terms of his "hypothesis"...


    (ii) the mathematic equation(s) based on planetary motions/cycles that encapsulates this series...


    (iii) your explanation of the manner in which this series (and the recent la Nina) can be explanied.

    Here's the La Nina years:


    (we could now add early 2006 and late 2007)

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