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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 130951 to 131000:

  1. Arctic sea ice melt - natural or man-made?
    Characteristics of the atmosphere can be divided into a mean state (as in zonal mean - averaged over all longitudes) and eddies. Eddy winds blow north and south, east and west; average of eddy wind velocity would be zero (unless...?). Eddy thermal anomalies are warm and cold; average is zero. But correlation can exist so that the average eddy heat and momentum fluxes are nonzero. These eddies are waves. They can propagate. They can be 'emitted' (generated, grow), can be reflected, can be absorbed, depending on the type of wave and conditions of the atmosphere.
  2. Is Pacific Decadal Oscillation the Smoking Gun?
    Thank you!
  3. Arctic sea ice melt - natural or man-made?
    Basic info on global circulation patterns: Troposphere: latitudinal variations in solar heating drive thermally direct Hadley cells - altered and enhanced by the role of water vapor: Widespread sinking over subtropics; adiabatic warming, radiative cooling. Rising in cumulus convection (hot towers) in the ITCZ - latent heating, adiabatic cooling. Seasonal Variation in forcing: ITCZ migrates north and south; the most intense Hadley cell is from the ITCZ to the winter subtropics. Seasonal land-sea contrasts: monsoons, enhanced by water vapor (latent heating). Also, Walker Circulation. Hurricanes, cumulus convection, land-sea breezes and mountain-valley breezes. -- Baroclinic instability in midlatitudes: Eddies carry heat polewards, concentrate zonal (westerly) momentum from north and south, transfer zonal momentum downwards to surface. Drives a thermally-indirect Ferrel Cell. -- Stratosphere and Mesosphere: Radiative equilibrium would be a temperature maximum around stratopause, Latitinal variation is - in lower stratosphere, warmest on the summer-side of the equator, but still cooler at summer pole; going up, latitude of greatest temperatures shifts all the way to summer polar region (happens while still in stratosphere). Winter polar region very cold. Circulations driven by propagation of mechanical energy upward from troposphere drive stratospheric and mesospheric motions that alter the temperature distribution: Quasi-stationary planetary waves produced in the troposphere can (under certain conditions) propagate upward - this can only happen with westerly winds with certain ranges of speeds - this happens in winter; not in summer. In winter, planetary waves propagate upward and dissipate in the stratosphere, which drives poleward motion; BREWER-DOBSON circulation in the stratosphere is upward over tropics, poleward into the winter hemisphere, and downward at higher latitudes. This warms the mid and high-latitude lower stratosphere and cools the tropical tropopause. Sometimes this happens in bursts called 'sudden stratospheric warmings'. But on average the winter polar stratosphere is still colder than the winter midlatitude stratosphere. Some gravity waves produced in the troposphere can propagate up to the mesosphere where they are dissipated, driving motion that is from the summer hemisphere to the winter hemisphere, with upward motion over the summer high latitudes and downward motion over the winter high latitudes. This cools the summer upper mesosphere and warms the winter mesosphere. Thus on average: At tropopause, coldest over tropics (the tropopause is highest over the tropics). In the lower stratosphere, summer polar region is warmer, tropics are colder, midlatitude winter is a bit warmer again, but the polar winter is colder. Higher in the stratosphere, there is a general decline in temperature from summer pole to winter pole. This continues somewhat into the mesosphere, except starting in the lower mesosphere winter high latitudes, the temperature gradient reverses; going up this condition spreads across the tropics and all the way to the summer pole, so that in the upper mesosphere and mesopause region, the summer pole is cold and the winter pole is warmer.
  4. Volcanoes emit more CO2 than humans
    That last comment was about "'Dead' planets might be livable after all". hope to get back to AO discussion within a few days...
  5. Volcanoes emit more CO2 than humans
    That was interesting. One important point is that the heat would take time to build up from such a process. In spite of all the Earth's internal heat, it counts little for regional or global scale climate (directly), because the heat flux is very small. For internal heat to make a difference to surface temperatures on a large scale, the heat flux has to be significant compared to the heating by radiation from the planet's star. Assuming a rocky crust as on Earth, the thermal gradient must then be that much greater, which means perhaps a thin crust on a molten mantle.
  6. It's the sun
    It is becoming more apparent that we picked either a very bad time or a very good time to screw with mother nature because the earth itself is very active as well as the sun. This is not a coincidence.
  7. Volcanoes emit more CO2 than humans
    Patrick I found a little more background data: Evidence Mounts For Arctic Oscillation's Impact On Northern Climate: ScienceDaily (Dec. 20, 1999)- A growing body of evidence indicates that a climate phenomenon called the Arctic Oscillation has wide-ranging effects in the Northern Hemisphere and operates differently from other known climate cycles. Arctic Oscillation Has Moderated Northern Winters Of 1980s And '90s: ScienceDaily (July 10, 2001) - The Arctic Oscillation has been linked to wide-ranging climate effects in the Northern Hemisphere, but new evidence shows that in recent decades it has been the key in preventing freezing temperatures from extending as far south as they had previously. Synchronized Chaos: Mechanisms For Major Climate Shifts: ScienceDaily (Aug. 2, 2007) — In the mid-1970s, a climate shift cooled sea surface temperatures in the central Pacific Ocean and warmed the coast of western North America, bringing long-range changes to the northern hemisphere. It seems that someone has been ignoring this data for quite a few years now. I wonder why.
  8. CO2 measurements are suspect
    Re #7, Well yes, that's rather the point. If one wants to obtain reliable global estimates of atmospheric CO2 concentrations, it makes sense to sample the atmosphere in isolated locations far from major sources of CO2 production. So one expects to see a bit of variability of atmospheric CO2 in measurements made in industrialised countries especially in the Northern hemisphere, and of course there is the yearly plant growth/decay cycle dominated again by the N. hemisphere. However if one examines the yearly average of atmospheric CO2 in isolated locations (there are dozens of these), the variability is low. These locations give a good measure of the global CO2 in the well-mixed atmosphere averaged on a yearly basis. Obviously local measures of CO2 concentrations can be somewhat higher, especially in or near cities (where they can be locally very much higher). There's masses of data that indicate that rather obvious consequence of measuring near human sources of CO2 (industrial/transport/heating etc.). Clearly if one wishes to assess the extent to which global atmospheric CO2 concentrations are changing in time, one asesses the global average on the time scale of good atmospheric mixing (e.g. annually) at the wealth of sites in isolated locations far from CO2 sources... ..it ain't rocket science!
  9. Is Pacific Decadal Oscillation the Smoking Gun?
    Re #42: The infrared electromagnetic (EM) radiation reaching the earth's surface is transformed to thermal energy which is re-irradiated eventually as longwave infrared (IR), having a lower energy than the incident IR. This longwave IR has energies that overlap with those of the vibrational transitions of certain atmospheric gases. These are molecules with asymmetric bond vibrations; i.e. CO2, H2O, CH4 and others (symmetric diatomic molecules that dominate the atmospheric composition - O2 and N2, don't absorb this longwave IR). So electronic transitions aren't excited, nor are bonds broken. However the absorbed longwave IR is either re-emitted by the greenhouse gas molecules, or else the gases transfer their thermal energy to other molecules directly by collision (thermal energy is essentially the same as heat). This has the effect of suppressing the escape of IR into space, and thus warming the atmosphere. In other words, the longwave IR emitted by the earth's surface radiates essentially "upwards" into towards space; however the "trapped" IR is re-emitted in all directions, and so the return of thermal energy to space is suppressed. I suspect that's what the sentence is summarising...
  10. CO2 measurements are suspect
    Well, the World Data Centre for GG's shows more than 1% differences...eg... Syowa Station * Japan NOAA/GMD 13CO2 2007 379ppm Hegyhatsal * Hungary HMS CO2 2007 405ppm Minamitorishima * Japan JMA 2008 380ppm Puszcza Borecka/Diabla Gora * Poland 2008 398ppm A small sample, there are others. 7% differential....5% differential; a bit difficult to accept the idea that there are no significant global variations in CO2 levels. Especially when no-one has bothered to measure the rather large areas mentioned in #1
  11. Human CO2 is a tiny % of CO2 emissions
    Depends what you define as 'short', 'medium' or 'long'. Yes, atmospheric CO2 levels have risen in the last 50 years or so....is this short or medium? Climate-wise I suggest it is very short. Paleoproxy data shows atmospheric CO2 rising and falling by very much greater levels over longer periods of time. The system is clearly never in equilibrium. 'More or less in balance' is a cop out. How much out of balance does it have to be before you consider it not in equilibrium? How does all that CO2 locked up as carbonate sediment compare to the oil/gas/coal deposits? And that form of sequestration is still going on. Human population is expected to grow from 6 to 9 billion by 2100...which equals (roughly) 540 million tons of carbon locked up in people for say, 60 years? And yes, people die, but the release of carbon back to the environment is not immediate. No dynamic system can be in equilibrium...
  12. Is Pacific Decadal Oscillation the Smoking Gun?
    I have a question - my grasp on physics is pretty basic and I was using this article to make a point on an internet forum and this was the response I got. Can you possibly give a brief explanation? "Greenhouse gases absorb outgoing longwave radiation" I am not sure what this is trying to say. The absorption of energy must culminate in some sort of effect. Either the energy excites e-, causing it to jump from a lower energy level then falling back again; emitting light during the drop. Or the energy absorbed breaks bonds. Or the energy is reflected. Do you know what this is trying to say?
  13. It hasn't warmed since 1998

    It is unclear how the calculation at 15 was made. NOAA data is available at LINK and Hadley data at http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt . These both show a trend of about +0.1 degree per decade. Although short term trends can be misleading, like the 22 year run up from 1976 to 1998, the dramatic drop of global average temperature in 2008 may be indicative of a change in character of the climate. The current UAH satellite numerical data (these data consist of the differences of lower atmospheric temperature from the 1979 thru 1998 average) is at http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt . According to these data, the AVERAGE GLOBAL TEMPERATURE for the first 9 months of 2008 is LOWER than the average from 2000 thru 2007 by an amount equal to 43.1% of the total linearized increase (NOAA data) during the 20th century. Since 2000, the CARBON DIOXIDE LEVEL HAS INCREASED by 14.4% of the total increase since the start of the Industrial Revolution.

  14. It's the sun
    pps Sorry, I put it in the "CO2 measurements are suspect" thread since I could not find a more pertinant thread for it.
  15. It's the sun
    chris Re: Otherwise it's not obvious - Greenhouse gases yes, to some large extent. But there is still more to it in my view. PS I put a link to yet another GHG in the volcano thread that might interest you.
  16. CO2 measurements are suspect
    Nice pudding Quietman, but it doesn't really go with the main course. This thread (and my posts) is about the accuracy of global CO2 readings and the mixing of the atmosphere on the annual timescale. The fact that efforts are being made to measure the concentrations of atmospheric NF3 is a seperate issue and not related at all to the accuracy of atmospheric CO2 measurements. Note that NF3 concentrations are extraordinarily low (I calculate around 42,500,000 times lower that those of atmospheric CO2 based on the info in your link)...no doubt it hasn't been easy to measure these...or perhaps no one has bothered up to now...
  17. CO2 measurements are suspect
    chris May I offer you a little pudding perhaps.
  18. There's no empirical evidence
    Re #11 A skeptic would easily recognise that Beck's analysis is nonsense! see, for example, post #172 here: http://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm remember that this is a "skepticalscience" site...we should make at least a little effort to be skeptical!
  19. It's the sun
    Re #179 Well yes, the large scale global warming of the last 30-odd years hasn't had a significant solar component. If anything the solar contribution has been a slight cooling one during the last several decades. Even those that push for solar contributions such as the cosmic ray flux concede that the solar contribution has been negligible at best. So solar contributions to warming in recent decades just isn't a viable proposition. The evidence is flat against it. Otherwise it's not obvious what else can have contributed significantly to warming other than the very well characterized massive enhancement of the Earth's greenhouse effect.
  20. It warmed before 1940 when CO2 was low
    Re: #2 (and #1) ..and yet there is a massive amount of evidence that the warming of the last 30 years is not "natural". The warming has followed the truely massive increases in CO2 emissions especially since the 1960's. Atmospheric CO2 concentrations rose rather slowly throughout the early 20th century. They were approaching 300 ppm in 1900 and reached 320 ppm in 1962. Since then we've raced up to 386 ppm. That's the likely source of the large scale global warming of the last 30-odd years. So to suggest that "our contribution, of various sources, not just CO2 is negligible" (whatever that might mean!) just doesn't accord with the real world evidence. I'd like to know what these "arguments presented against CO2" that "have some merit" actually are...can we have a list please?
  21. Is Antarctic ice melting or growing?
    Re #15 Monaghan and Bromwich seems to me to be essentially confirmatory in relation to our understanding of the Antarctic and the implications of a warming world. They point out that while the Southern oceans have warmed significantly in the last few decades, that this hasn't resulted (as far as we can tell) in enhanced snow deposition. They suggest that a predicted 2-3.5 oC of Antarctic warming in the current century might yield a 10-20% increase in snowfall, with a potential mitigating effect on sea level rise. However it's not clear (to me anyway!) whether this relates to NET Antarctic mass. After all, a 2-3.5 oC temp rise in the Antarctic (there hasn't been much overall warming there so far, much as models predicted) might be expected to yield significant melt at the continental margins (as we're seeing in Greenland), which might or might not balance or overpower excess snow deposition... There's a certain extent to which this is somewhat academic. Other than the expected mass loss in the Antarctic peninsula and to a lesser extent in the West Antarctic ice sheet, significant Antarctic ice mass loss hasn't been much factored into the consequences of global warming. As predicted by models from 20 years or so ago (see post #66 in the "Arctic sea ice - natural or man-made" thread: http://www.skepticalscience.com/Arctic-sea-ice-melt-natural-or-man-made.html ..Antarctica is partly insulated from the effects of global warming largely due to the peculiar ocean currents in the deep Southern latitudes, and the very efficient transfer of thermal energy to the high Northern latitudes. So the concerns (in relation to sea level rise) in a warming world relate largely to Greenland. No one expects Antarctica to melt significantly. Monaghan and Bromwich is consistent with that expectation. I'd still like to know whether they consider that their modelling of enhanced snow fall through the latter parts of the 21st century, due to enhanced Antarctic temperatures in a world warming under the influence of enhanced greenhouse gases, is a NET contribution to sea levels, or is independent of any warming-induced contribution to sea level rise from enhanced melt at the low altitude continental margins. I get the impression from their paper that they haven't considered the latter....that's not what their paper is about....
  22. Volcanoes emit more CO2 than humans
    Patrick In a new article at MSNBC titled ‘Dead’ planets might be livable after all they explain planetary tidal forces in the manner that I see them (inferring from the Solar Jerk) but carried to more of an extreme than we experience. The hypothesis is the same however, it's only a matter of degree.
  23. Models are unreliable
    It was somewhat surprising to discover that the study of climate science does not require any exposure to the ‘theory’ (it is widely and successfully applied practice in some engineering disciplines, especially electrical, mechanical and aeronautical) of dynamic systems with feedback control. Their ignorance has resulted in climatologists coming up with their own expression for feedback and the perception that feedback in climate is somehow different from feedback in other systems. In effect it isn’t (for more, see 49 above). Earth’s climate is a dynamic system that is controlled by NET feedback. A lack of understanding of dynamic systems with feedback and how they work has resulted in many articles being published that a reviewer who was knowledgeable in dynamic systems with feedback would quickly recognize as patently false. Climate publications are staffed by climate scientists. Articles for publication in climate publications are peer reviewed by climate scientists. None of them appear to be knowledgeable in dynamic systems with feedback and thus they are unable to recognize information that is readily shown to be false and should never have been published. Feedback means that the output (results, response) influences the input. Feedback can be positive or negative. Positive feedback means that the output is greater than it would be without feedback. Negative feedback means that the output is reduced from what it would be without feedback. Net feedback is the effective feedback when there are both positive and negative feedbacks. If net feedback is positive the trend must continue up at a progressive rate. The effect on a savings account balance with compound interest is a familiar example of net positive feedback. Complexity does not alter how net feedback works. Now look at any credible historic temperature data. To be credible, a temperature trace must be for a long enough time to average out cyclic variation from random noise and other factors such as ENSO. The temperature trace does not even need to be correct in absolute terms just reasonably valid in relative terms time-wise. It should also be substantially longer than any smoothing period that was employed in generating the data set. A temperature trend can not change direction from up to down if net positive feedback exists. If there is at least one change of average global temperature trend from up to down (a down trend of average global temperature can not exist with net positive feedback) without an overpowering external influence, it proves that net positive feedback does not exist. There are many and there are downtrends. Therefore net positive feedback does not exist. Without net positive feedback the climate computer models (GCMs) do not predict significant global warming from increased atmospheric carbon dioxide. There are other issues with GCMs and their use as described at 32 above. Climate scientists and climate scientist wannabes who claim that ‘the science says’ are simply ignorant of an important part of science that is relevant to the issue. Climate scientists, in their ignorance, impose net positive feedback on their GCMs which causes them to falsely predict that added atmospheric carbon dioxide causes significant global warming.
  24. Is Antarctic ice melting or growing?
    A 2008 paper by Monaghan and Bromwich takes a different approach to the Antarctica question. http://polarmet.mps.ohio-state.edu/monaghan/papers/monaghan_bams_7747.pdf They look at 50 years of temperature and snowfall records for the continent. With temperatures they note that "In contrast to widespread temperature increases globally, instrumental records indicate statistically insignificant (p>0.05*) seasonal and annual near-surface temperature changes over continental Antarctica from the late 1950s through 2000." Snowfall data has larger uncertainties and cyclical changes, but they write "there has been little overall change in Antarctic snowfall during the past 5 decades" When looked at on decadal time scales, atmospheric models indicate that snowfall over Antarctica could possibly rise by as much as 5% for each 1°C increase in temperature. The researchers write that "if global climate model projections of 2-3.5°C temperature increases over Antarctica by the end of this century are accurate a ~10%-20% increase in snowfall might be expected if the 1960-2004 sensitivity relationship holds." And in this regard, they note that "a 15% increase of Antarctic snowfall would mitigate an additional ~1 mm per year of global sea level in 2100 compared to today."
  25. CO2 lags temperature
    Really Quietman? What specific ("more recent..") evidence informs your opinion that the greenhouse effect doesn't supplement the Earth's global temperature such that we are around 30 oC warmer than we would otherwise be without the greenhouse effect (taking into account the variations I pointed out in 14 and positions of the continents and that sort of thing)? Which specific concepts that were "assumed it to be correct" are now "also incorrect"? In what manner specifically does the determinations "more recently" "point in the wrong direction"? Please be specific.
  26. Ice age predicted in the 70s
    Re #3: It's easy to be misled by the titles of papers. The examples you've asserted as supporting a 1970's perspective of global cooling don't actually do so. Your second article sounds like it does: Convection in the Antarctic Ice Sheet Leading to a Surge of the Ice Sheet and Possibly to a New Ice Age T. Hughes, Science Vol. 170. no. 3958, pp. 630 - 633 (1970) But it's just a potentially misleadingly worded title. If you read the paper it's got zero relevance to a possibility of a "new ice age" in the near (i.e. "near" from a 1970 perspective). It's about the GENERAL nature of ice Antarctic ice sheet advance that might (within a particular "surge" theory) be linked to the glacial cycles within the Pleistocene. So it's about how glacial periods might in general occur. That's very clear from reading the paper. It's also evident just from reading the abstract: abstract: "The Antarctic surge theory of Pleistocene glaciation is reexamined in the context of thermal convection theory applied to the Antarctic ice sheet. The ice sheet surges when a water layer at the base of the ice sheet reaches the edge of the ice sheet over broad fronts and has a thickness sufficient to drown the projections from the bed that most strongly hinder basal ice flow. Frictional heat from convection flow promotes basal melting, and, as the ice sheet grows to the continental shelf of Antarctica, a surge of the ice sheet appears likely." So it's a theoretical study of a mechanism for ice sheet advance during glacial cycles. It doesn't address the possibility of any such event during the current Holocene, and has nothing to do with 1970's scientific perception of global warming or cooling or any such thing. Likewise it's understandable why Peterson et al. didn't include your other paper as a "cooling"/Ice Age" one: Return of the ice age and drought in peninsular Florida? Joseph M. Moran, Geology 3 (12): 695-696 (1975) Although the title (and the rather odd abstract) might suggest that the paper is about the "return of the ice age", the question mark highlights the fact that the author is rather equivocal over such a conclusion. Here's how he ends his (very brief) note: "While there is an interesting parallel between recent and late-glacial events in the tropics, no clear cause-effect relation has been established between the current hemispheric cooling trend and precipitation trend in peninsular Florida. Also, even if a linkage were established, there is no certainty that the hemispheric cooling trend will not reverse itself in a few years. Rather than portraying a bleak future for Florida’s water supply, therefore, the observations presented here should serve as stimuli for further monitoring and research to promote understanding of the controlling atmospheric phenomena." In other words, the paper relates to precipitation trends with potential implications for water supply in Florida, and the author indicates that there isn't any necessary relation between cooling and precipitation trends and indicates anyway that the cooling trend might reverse itself. So neither of your suggestions - absolutely not the first one which is totally irrelevant to 1970's perspective on cooling/warming or otherwise, - nor the second one can be taken to support the notion of any 1970's scientific perception of global cooling (by the criterion that Paterson et al. set of a paper with a clear projection of climate change or discussing an aspect of climate forcing relevant to time scales of decades or centuries). Morgan's short note doesn't come to any conclusion - the "cooling" "...might reverse itself in a few years".
  27. Arctic sea ice melt - natural or man-made?
    Patrick Re: Ozone - Agreed Somewhere here there are links to papers on ozone that agree with what you said (I don't remember where).
  28. Arctic sea ice melt - natural or man-made?
    ... But also: ozone chemical reactions will be affected by temperature. Temperature affects circulation. Ozone affects temperature. Circulation affects temperature and ozone. The enhanced warming at low levels in high latitudes, is strongest in the colder months, and might actually be reversed (reduced warming relative to some other latitudes, at least over water (?)) in some portion of the summer or near that time.
  29. Arctic sea ice melt - natural or man-made?
    10. Some thoughts: Temperature changes at the surface and lower troposphere will have a radiative effect on the stratosphere. Especially when any intevening clouds or high water vapor concentrations are close enough to the surface, there will be a band of wavelengths in which the surface radiates up to the ozone layer. Since the high latitudes (northern hemisphere) warm more than the low latitudes, this will tend to warm the northern polar stratosphere more. However, the latitudinal trend is reversed in the upper troposphere, which will substitute radiation from below with it's own, to varying degrees, depending on wavelength, cloud top heights, etc. Yet, to begin with, I think the latitudinal trend is greater at lower than upper levels, and the increased greenhouse effect will shield the stratosphere more from the surface, and this would tend to warm the polar stratosphere more than the lower latitude stratosphere.** Increased solar UV should produce more ozone. Higher ozone concentrations would push the distribution of solar heating upward a bit. Relative to the local vertical distribution of ozone, solar heating (by UV) will be more concentrated toward higher levels at higher latitudes and in winter, because of the angle of the sun's rays (a longer path length fitting into the same vertical distance).
  30. Climate sensitivity is low
    re #25: I forget to give the url to Schwartz's reassessment/correction of his original work: http://www.ecd.bnl.gov/steve/pubs/HeatCapCommentResponse.pdf
  31. Climate sensitivity is low
    It's worth pointing out that Stephen Schwartz has recognised some of the essential errors in is analysis (see John Cook's top article and also my post #5), and has issued a correction in relation to the original analysis that everyone got very excited about. Now Schwartz considers that his analysis (still a rather weak approach - see Tom Cook's top post and my post #5), yields a climate sensitivity of 1.9 +/- 1.0 oC per doubling of atmospheric CO2. That's within the range of all the pukka science out there (a climate sensitivity near 3 oC +/- a bit), and if Schwartz were to relax his (rather arbitrarily determined) time constant for the earth's inertial respense to forcings a bit more, then he'd be smack on the value that everyone else gets. So another storm in a teacup! Sadly, while Schwartz's original paper was flashed all over the blogosphere, we can be pretty sure that Schwartz's reassessment will be left unmentioned... ..but not here!
  32. Arctic sea ice melt - natural or man-made?
    Re Quietman 4 (links): 10. "Evidence mounts for Arctic Oscillation's impact on northern climate" http://www.washington.edu/newsroom/news/1999archive/12-99archive/k121699.html "The Arctic Oscillation is a seesaw pattern in which atmospheric pressure at polar and middle latitudes fluctuates between positive and negative phases. The negative phase brings higher-than-normal pressure over the polar region and lower-than-normal pressure at about 45 degrees north latitude. The positive phase brings the opposite conditions, steering ocean storms farther north and bringing wetter weather to Alaska, Scotland and Scandinavia and drier conditions to areas such as California, Spain and the Middle East. In recent years the Arctic Oscillation has been mostly in its positive phase, research has shown. "In its positive phase," Thompson said, "frigid winter air doesn't plunge as far south into North America," meaning warmer winters for much of the United States east of the Rocky Mountains, while areas such as Greenland and Newfoundland tend to be colder than normal." ... "Stratosphere cooling in the last few decades has caused the counterclockwise circulation around the North Pole to strengthen in winter. In turn, the belt of westerly winds at the surface along 45 degrees north latitude has shifted farther north, the scientists said, sweeping larger quantities of mild ocean air across Scandinavia and Russia and bringing balmier winters over most of the United States as well." The Arctic Oscillation is an alternate view of what many scientists call the North Atlantic Oscillation, the researchers said. Year-to-year fluctuations in the North Atlantic Oscillation are thought to be prompted primarily by changes in the ocean, as with El Niño. However, Wallace, Thompson and Baldwin argue that the North Atlantic Oscillation is in fact part of the Arctic Oscillation, which involves atmospheric circulation in the entire hemisphere. They say the trend toward a stronger, tighter circulation around the North Pole could be triggered just as well by processes in the stratosphere as by those in the ocean. The trend in the Arctic Oscillation, they said, has been reproduced in climate models with increasing concentrations of greenhouse gases." Very interesting. Presumably solar and volcanic forcings, etc. would also have effects on stratospheric temperatures and thus could also affect stratospheric-tropospheric interactions. I've read that current (AO)GCMs (computer climate models) don't resolve or have trouble resolving some circulation processes of the upper atmosphere. However there is no reason to suspect that increased knowledge about this will lead to a conclusion that significantly reduces anthropogenic forcings' roles relative to other things. (It sounds like, perhaps, the changes in tropospheric circulation associated with AO (?) (Arctic Oscillation - same as NAM? - North(ern ...) Annular Mode ?) rearrange heat but don't directly result in a change in global average temperature by that - except of course, there could/will be feedbacks which might have some global average tendency one way or the other.) I'll have to look more into this. But a few quick notes for now: Increased/decreased horizontal temperature gradients increase/decrease vertical geostrophic wind shear - wind speed above increases/decrease or wind speed below does the opposite or both. Geostrophic winds in the stratosphere (and mesosphere, etc.) is affected by tropospheric conditions, and vice versa, as it is for parts of these. Wind direction is also potentially affected. Vertical motion can transport momentum. Perhaps less obviously but more importantly (?), interactions among various layers can transfer momentum vertically (vertical wind shear allows air to move into different conditions (as determined by the changing quality of air above and below) requiring it to accelerate in some way; the layers interact). Vertical interaction is generally reduced (at least for transient disturbances?) when stratification (vertical static stability) is greater - when temperature decreases with height less or increases with height more. (Imagine how much more intensive the mechanical interaction of ocean and atmosphere would be if the ocean were only 0.1 % of it's density.) 3. "Arctic Climate" http://nsidc.org/arcticmet/basics/arctic_climate.html "extreme solar radiation conditions" - This just refers to the seasonal extremes of insolation (At the pole, 6 months of darkness, 6 months of daylight with low sun angle, etc.).
  33. Arctic sea ice melt - natural or man-made?
    0.2 - models This is only tangentially related, but it has been argued that evidence exists for solar forcing on other planets. This isn't a very strong argument. What's ironic is - from the little I've read about it - the argument that Jupiter's climate is changing - it's ironic because the changes that have occured seem to be a form of internal variability, and may have been predicted by a computer model! (Now I'm going to another part of this website to double check that.)
  34. Arctic sea ice melt - natural or man-made?
    chris Sorry, I had been discussing Hansen and RC with Phillipe and Patrick and got confused. Chalk it up to a senile moment.
  35. Arctic sea ice melt - natural or man-made?
    Patrick Thank you for your thoughts on this. Quite logical and I agree with your summation.
  36. Arctic sea ice melt - natural or man-made?
    (PS thanks, chris) ... Just for insight's sake: Two other dark horse candidates: 1. solar eclipse frequency and spatical distribution changes. 2. Changes in 'moonshine' (averaged over the lunar month) or variations in 'moonshine' (changes in lunar cycle) Both these being due to variations in the orbits of the Earth around the sun and moon about the Earth. Of course, without even bothering with explicit calculations, I would rule these out off the bat as significant to climate variations on just about any timescale - with one intriguing caveat: I wonder what effect these (and the tides) might have had in the first several millions (? - unsure of how fast the moon receded) of years of Earth's history (after the moon-forming impact, of-course - and some cooling; I doubt it would be of much significance to climate over a magma ocean!).
  37. Arctic sea ice melt - natural or man-made?
    To clarify - just to be clear, while I mentioned that some feedbacks to any warming should tend to cool the stratosphere - although others may warm it - my understanding is that the expectation of warming stratosphere from positive solar solar forcing and cooling stratosphere from positive GHG forcing both include the expected feedbacks. Of course, feedbacks won't be exactly as expected, but the individual feedback components might be observed and their effects calculated and compared to the model feedback effects, etc... (I don't know if that's really been done or not or how much). Summarizing the gist of all that - while feedbacks have uncertainties, the forcing mechanism and amount is well understood for GHGs, solar TSI (maybe a bit more uncertainty with amount), and volcanic aerosols. Anthropogenic aerosols have more uncertainty. One could make a list of dark horse candidates (PDO-ENSO cloud feedback (as in Spencer) greatly magnifying internal variability, tidal forcing - oceanic effects, geothermal variations, geomagnetism and non-TSI or non-UV solar forcing) - for some of these, a potential for a mechanism can be identified, though at least for me there is skepticism that the magnitude of the effect could be significant; for others, mechanisms can be imagined but there is a lack of information about their reality (to my knowledge). For others, there may be enough information already to rule out any significant contribution at least to the recent climate change on the AGW-relevant time-scale. Or some middle ground among those three conditions may apply. (I did my best to reason through some of this in "It's volcanoes"...) One thing these (those with potential, anyway) all have in common, to varying degrees, is greater uncertainty regarding any potential significance. This is in addition to any climate feedbacks, so without some specific reason to the contrary, there is greater uncertainty with these than with the more 'established' climate forcings. Note that it generally makes more sense to use what is known to shed light upon the unknown (ie that using what we know, we either can or can't explain observations/data, to whatever degree; therefore it is less likely or more likely, to whatever degree, that something we haven't accounted for is important after all) than it does to take the potential for importance of unknowns to find error in what was thought to be known.
  38. Arctic sea ice melt - natural or man-made?
    Re #265 Quietman, the reassessment of tropospheric temperature measurements, especially those over the tropics, were the results of the efforts of a large number of scientists who identified artifacts especially in the radiosonde readings. This work is very widely published in the scientific literature (several of the relevant papers highlighting the radiosonde errors are listed in my post #263, just above). The resolution of apparent disparities between models and tropospheric emperatues has been widely resolved (see report of the Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research cited in my post #263)....the more specific resolution of apparent disparities in the tropical data is described in this paper: B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. None of this has any particular relationship to Real Climate (where did you get that idea?). It's widely verifed research from a large number of different sources published in the scientific literature. So nothing to do with Real Climate, but everything to do with careful science published widely in the scientific literature!
  39. Arctic sea ice melt - natural or man-made?
    Patrick On the double error you are right, I repeated what I read and should have known better since it is not a linear response. I apologise for repeating the error. I don't remember where I read it now as it was about a year ago. chris Re: 263 - I was aware of this and agree. Re: models - I posted a link to an article from 2007, I think october, on model accuracy/inaccuracy in the appropriate thread here under the "arguments" heading a while back. As far as I am aware your point FIVE is the opinion expressed on Real Climate but I have not seen it on any other web site, and as you know I do not trust that site. Too much of an agenda there.
  40. Arctic sea ice melt - natural or man-made?
    Re Quietman 259/151 You might be interested in reading my post #263, since it was you (your post #151) who initially questioned the predictive powers of modelling. In addition to Patricks examples, the examples in post #263 document pretty unequivocably that: ONE: the marked asymmetry between Arctic warming (it was predicted to warm a lot) and Antarctic warming (very little in the early stages of greenhouse waming), was predicted already in the early-mid 1980's TWO: That the extent of warming by the year 2000 was predicted rather accurately in 1975 by Wallace Broecker THREE: Hansen's models set up in the early 1980's have done a good job in predicting the temperature rise in the subsequent 20 years (notwithstanding various efforts to trash this work-see Patrick's post #262!) FOUR: Model predictions of enhanced tropospheric moistening were shown to be correct despite strenuous efforts by at least one prominent scientist to suggest that the models would be wrong. FIVE: Model predictions of enhanced tropospheric warming were eventually vindicated despite apparent discrepencies with real world measurements, the latter turning out to have been incorrect. So climate modelling has done a pretty good job so far of predicting multiple effects of massive enhancement ofr atmospheric greenhouse gas levels.
  41. Arctic sea ice melt - natural or man-made?
    Re #258 Patrick (in reference to your response to the Monty Python style "what did the Romans ever do to us" request in #151 for predictions "that pan out for a change"): The predictions of a greatly delayed response of the Antarctic to greenhouse-induced warming and a marked asymmetry of warming between the high Northern and high Southern latitudes, were made in 1981 by Schneider and Thompson, and in more detail by Bryan et al in 1988. Describing these early modelling predictions of a greatly reduced Antarctic warming compared to predicted enhanced warming in the high Northern latitudes, Manabe and Stouffer state [in their recent review: Role of Ocean in Global Warming; J. Meterolog. Soc. Jpn. 85B 385-403.(2007)]: [“They [Bryan 1988] found that the increase in surface temperature is very small in the Circumpolar Ocean of the Southern Hemisphere in contrast to high latitudes of the Northern Hemisphere where the increase is relatively large.”] In other words the very marked asymmetry between the marked warming of the high Norther latitudes, compared to the very small expected warming in the deep S. hemisphere was predicted at least 20 years ago. I've outlined this in more detail in my post # 66 on this thread. Some other examples (of quite a large number in addition to your examples) in which climate predictions from calculations and modelling have turned out to be prescient (i.e. reality has subsequently matched the models): In addition to Hansen's rather good prediction of greenhouse gas warming from models set up and run from the early 1980's it's worth pointing out that already in 1975, Wallace Broecker was calculating (i.e. modelling) the warming expected in the future from continuing increases in greenhouse gas emissions: In his paper: Broecker, WS (1975) “Climate Change: Are we on the brink of a pronounced global warming? Science 189, 460-463 Broecker says (referring initially to the small N. hemisphere cooling observed in then-recent times): "...This cooling has, over the last three decades, more than compensated for the warming effect produced by the CO2 released into the atmosphere as a by-product of chemical fuel combustion. By analogy with similar events in the past, the present natural cooling will, however, bottom out during the next decade or so. Once this happens, the CO2 effect will tend to become a significant factor and by the first decade of the next century we may experience global temperatures warmer than any in the last 1000 years….” Broecker then goes on to describe predictive modelling of anthropogenic CO2-induced warming, taking account known levels of CO2 emissions from the UN and a projection (3% per year) of the increase in emissions, the best estimates from measurements of the emitted CO2 sequestered in the oceans and the terrestrial environment and the known warming properties of atmospheric CO2. His modelling came up with the following prediction. The Earths temperature in 2000 would be around 0.9 oC warmer than the 1900 baseline temperature. The Earth is around 0.8 oC warmer now than it was at the start of the 20th century. Not a bad prediction. Why was his prediction so good? I expect he was partly lucky since the strengths of the various contributions to climate were not so well known then as now. But, basically he was about right because the effects of atmospheric CO2 in causing warming of the Earth via the greenhouse effect were well known and easily calculated. Two other related examples of the rather strong predictive power of climate and atmospheric modelling are interesting, since in each case the predictions initially semed like they might not accord well with reality (and in the first case was strongly argued against by at least one prominent scientist) ONE: Atmospheric greenhouse theory, incorported into climate models predict/ed that as the atmosphere warms in response to raised CO2, so the atmospheric water vapour levels would rise. This prediction was strongly opposed by a very few scientists, most notably Richard Lindzen, who asserted that the troposphere would dry in response to raised CO2 levels providing a negative feedback. In fact the data eventually showed that the presictions from models were correct [see Soden et al (2005); Brogniez H and Pierrehumbert RT (2007); Santer BD et al. (2007); Buehler et al. (2008); Gettelman and Fu (2008)…and so on (citations below]. An example where a major prediction from modeling was contested, but the models were subsequently vindicated by real world measurements. TWO: Atmospheric greenhouse theory incorporated into climate models predict/ed that the troposphere should warm relative to the surface. Early tropospheric temperature measures seemed to contradict this prediction. However it turned out in time that errors in tropospheric temperature measures were responsible for the discrepancy and by 2006 the U.S. Climate Change Science Program (CCSP) who investigated this issue stated that there is ‘no significant discrepancy’ between surface and tropospheric warming, consistent with model results (Karl et al., 2006). However there has still remained a potential discrepancy between model predictions and tropospherical temperature measurements in the tropics. However recent work has again shown that the errors likely lie in the temperature measures (largely radionsides/weather balloons) [see Sherwood (2005); Thorne (2007); McCarthy (2008); Haimburger (2008)], and again it appears that the predictions from the models have turned out to be correct (Santer et al 2008). B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. ------------------------- 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 Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110 Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289 Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253 Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844. ----------------- S. C. Sherwood et al. (2005) Radiosonde Daytime Biases and Late-20th Century Warming Science 309, 1556 – 1559. L. Haimberger et al (2008) Toward Elimination of the Warm Bias in Historic Radiosonde Temperature Records—Some New Results from a Comprehensive Intercomparison of Upper-Air Data. J. Climate 21, 4587-4606. M. P. McCarthy et al. (2008) “Assessing Bias and Uncertainty in the HadAT-Adjusted Radiosonde Climate Record”. J. Climate 21, 817-832. P. W. Thorne et al. (2007) Tropical vertical temperature trends: A real discrepancy? Geophys. Res. Lett. 34, L16702. ---------------- Karl TR, Hassol SJ, Miller CD, Murray WL (eds). 2006. Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. National Oceanic and Atmospheric Administration, National Climatic Data Center: Asheville, NC; 164.
  42. Arctic sea ice melt - natural or man-made?
    0.1 (PS after a while you might figure out what these numbers meand): Attribution: To clarify: "Just once? To repeat from above, stratospheric cooling"... "increased warming of nights" ... I also noted that stratospheric ozone depletion could also qualitatively explain stratospheric cooling (and some amount of tropospheric+surface (TPSF for future reference) warming ), and that albedo cooling such as from aerosols (of the right mix) could also qualitatively explain a decrease in diurnal temperature ranges. One key there is 'qualitatively' - for attribution, one would want the numbers. If one expects x degrees change from forcing A and y degrees change from forcing B, then one might start by looking at z/(x+y), where z is the observed change, and attribute z proportionately. One then may need to adjust that if there is some reason to suspect that the relative error in modeling/calculating is different for x and for y. If x can be modelled with more confidence than y (***ie if for x relative to y, the physics are better understood, model resolution and sub-grid scale issues are less of a concern (such as if y depends more on a smaller part of the atmosphere in particular?), or if forcing A is better known than forcing B), then it may make more sense to asign a greater likely share of the theory-observation mismatch to y. However, it would be erroneous, without some reason to do so, to just assume that y was correct and x is off or vice versa. (PS this would also apply when unforced variability is thrown into the mix). The other key is that there may additional aspects that are different for the climatic response to each forcing (as similar solar and GHG forcing of TPSF temperatures have different effects on the stratosphere). For example, increased albedo of course has a cooling effect and can't by itself explain an average TPSF warming (and there could be more subtle differences among different albedo forcings - volcanic vs tropospheric vs land cover). Absorbing atmospheric brown clouds would tend to increase the diurnal temperature range of the air volume they occupy (but that's not much to begin with, away from the surface)but could decrease the surface range, so that would be a candidate. Of course, the horizontal variations of these various aerosols and land-cover matters are quite different and that opens up another avenue for distinguishing their effects. ... One could imagine some combination of solar forcing and aerosol forcing could result in warming with reduced daytime warming, but again, 1. How would the numbers work out exactly?, 2. Other effects - So far as I know no significant albedo enhancement exists that would cool the stratosphere (reflection from below and perhaps scattering from within (? and/or the nonzero absorptivity of even relatively reflective stratospheric aerosols) may tend to warm the stratosphere slightly - **** THEN again, some climate feedbacks themselves might cause some stratospheric cooling - decreased albedo at the surface, and water vapor and the LW (greenhouse) effect of clouds with sufficiently high tops - although an increase in albedo from increased cloud cover, except over or replacing snow and ice (PS clouds over snow and ice could in some cases reduce albedo, I think) would tend to warm the stratosphere for reasons described above... But there may be some horizontal variation fingerprints to these various processes... Well, there is yet another way to distinguish - seasonal variations - ozone has seasonal variations and anthropogenic changes to ozone has seasonal variations. The seasonal variations of solar and GHG forcings, etc, may also be different. The overall seasonal variations (and spatial variations) in climate response in TPSF may be too similar but perhaps some stratospheric responses might contain clues. Then of course, there's the thermosphere, which doesn't have much ozone (chemical equilibria favor atomic oxygen over ozone and at sufficient height over diatomic oxygen, actually) but has the opposite sign of response to solar and GHG forcing. There is also of course the longer term temporal variations - volcanic aerosols have distinct pulses, anthropogenic GHGs have steadily risen, anthropogenic aerosols have their own trend, solar, etc... this can get tricky because of the internal variability on those timescales, of course. To sum up, if you have n unknowns and m equations, you can solve for the unknowns if m = n. If m > n, then any random combination of equations may yield conficting results - mathematically they can't all be true; but - these equations aren't random - they're rooted in physics and must agree with each other. Uncertainty allows for some disagreement (the ranges of allowable values won't be identical, but using many equations would tend to reduce the resulting uncertainty in the unknowns (and perhaps would then feedback as knowlegdge about how to improve some of those equations). Science is putting together a puzzle; sometimes the puzzle pieces have fuzzy edges and they don't fit precisely but additional pieces can help decide which arrangement is most likely, etc... On internal variability - that will always make attribution a little difficult but refer back to above. If we understood the forced responses better than internal variability then it wouldn't make sense to assume any little wobble outside the expected range of variability would render our models incorrect with respect to a forced response - and certainly variations within the expected range of variability don't render models in error. 0. Quietman 259: "Re: Hansen's prediction - Off by 50%, He predicted exactly twice the warming that actually occurred." That's a common misunderstanding (which had been spread by Pat Michaels). A. http://www.columbia.edu/~jeh1/2005/Crichton_20050927.pdf B. http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000836evaluating_jim_hanse.html From the later: "Perhaps the errors cancel out, but an accurate prediction based on inaccurate assumptions should give some pause to using those same assumptions into the future." These errors are errors in emissions scenarios for different greenhouse gases. However, what matters to climate science, assuming similar efficacies of those GHGs, is the history of the sum of those forcings. From the earlier, in footnotes: " Climate sensitivity is usually expressed as the equilibrium global warming expected to result from doubling the amount of CO2 in the air. Empirical evidence from the Earth’s history indicates that climate sensitivity is about 3°C, with an uncertainty of about 1°C. A climate model yields its own sensitivity, based on the best physics that the users can incorporate at any given time. The 1988 GISS model sensitivity was 4.2°C, while it is 2.7°C for the 2005 model. It is suspected that the sensitivity of the 2005 model may be slightly too small because of the sea ice formulation being too stable. " I would guess then that running the same model from 1988 with the realized forcing history would produce a bit too much warming, but not so much more (assuming 2005 model is more accurate, (4.2-2.7)/2.7 = 1.5/2.7 = 5/9. Okay, that is just over 50 % error, BUT that is not twice the warming, that is just over 1.5 times the warming. And the last part of that footnote suggests the error may be a bit less than that.
  43. Arctic sea ice melt - natural or man-made?
    Re #259 I'm skeptical about your comments re Hansen's forecast of global temperature change under the influence of enhanced greenhouse-induced warming. You suggest that "he predicted exactly twice the warming that actually occurred." Can you indicate how you come to that conclusion? I'm interested in the evidence that informs your opinion..
  44. Volcanoes emit more CO2 than humans
    Patrick Your explanations and willingness to look at both sides is exactly why I asked you to come to this site. In most cases I can see your logic and find it convincing. Keep in mind that this type of science is new to me. I have a beckground in engineering research (product developement) and bench testing emissions but I have never done well with theoretical math only logic and applied math, so keep it simple. Trust me, it is just as frustrating for me when someone points to a paper and claims it as fact without a logical explanation as it is when I get quoted from a bible passage. The fact that you don't resort to that is quite refreshing.
  45. Arctic sea ice melt - natural or man-made?
    I will try to reply to the rest when you finish your analysis. Sounds good so far.
  46. Arctic sea ice melt - natural or man-made?
    Patrick Re: Fire and Ice - Sorry, I should have. Re: Hansen's prediction - Off by 50%, He predicted exactly twice the warming that actually occurred.
  47. Does model uncertainty exagerate global warming projections?
    Wondering Aloud, HealthSkeptic, Mizimi I thought you guys (gals?) are supposed to be skeptics!So what do you make of the "graph" reproduced in post #8? Let's have some considered thought and opinion. (hint: The data presented is nonsense - can you see why?)
  48. Arctic sea ice melt - natural or man-made?
    (continued from comments 96 - 104, and perhaps 95, at "It's volcanoes (or lack thereof)") 1. 'solar dimming/brightenning' - I'm not sure what terms are used for what exactly here, but this is confusing, because it sounds like one is discussing solar TSI changes, when it was intended to discuss global dimming - the reduction in solar radiation reaching the surface. Global brightenning might not even be the opposite of that - I could imagine global brightenning might be used to refer to an incress in albedo as seen from TOA (top of atmosphere) - PS hypothetically if this occurs it could be seen on the dark portion of the moon - Earthshine reflecting off the moon's night side. I don't know if there are any observations indicating a trend in that or not. 2. Quietman 87: "Fire under the ice International expedition discovers gigantic volcanic eruption in the Arctic Ocean" http://www.eurekalert.org/pub_releases/2008-06/haog-fut062508.php You should post that website under "It's volcanoes"... - it's the first I've seen with actual evidence of a change in volcanism. However, the changes are still just on the scale of individual eruptions - Whether the the lack of knowlegde of prior such eruptions is an actual knowledge of a lack of prior such eruptions depends on whether it could have been expected to be noticed or missed - in this case I am very skeptical that there is any evidence at all of a trend here. And even if there were, I am very skeptical it could account for any significant portion of climate change, even regionally (consider the numbers - the actual geothermal heat output of an eruption compared to the actual heat going into the ocean - and by the way, remember that the global average geothermal heat flux at the surface is a little under 0.1 W/m2, and most of that is just thermal conduction through a temperature gradient in solid rock (and groundwater, but in most areas I don't think it's sufficient to drive groundwater convection?? or that groundwater flow is fast enough to cause rapid changes), with radioactive heat contributions - nothing that could change fast, except maybe where there's fast-flowing groundwater or hydrothermal vents, and how fast could those change on what timescales...?). 3. Notice in Quietman 107: "Surface warming by the solar cycle as revealed by the composite mean difference projection" "Charles D. Camp and Ka Kit Tung Received 29 March 2007; revised 15 May 2007; accepted 14 June 2007; published 18 July 2007. Geophys. Res. Lett., 34, L14703, doi:10.1029/2007GL030207." " [12] We will argue in a separate paper that the observed warming is caused mostly by the radiative heating (TSI minus the 15% absorbed by ozone in the stratosphere), when taking into account the positive climate feedbacks (a factor of 2?3) also expected for the greenhouse warming problem. " I haven't seen it myself but it sounds like they've found some reason to think that it is indeed solar TSI forcing at the tropopause (or nearly that) and not some aspect of solar forcing that wouldn't apply to GHGs - perhaps a difference in timing between TSI and solar wind variations, etc.? 0. Quietman 151: "The lies come from both deniers and alarmists, those of us who are skeptical do not need to lie, we simply ask for proof of your hypothesis. Make a prediction that pans out for a change, just once, and you will convince us skeptics. So far it's a no hitter. " Just once? To repeat from above, stratospheric cooling (with some qualifications because ozone depletion contributes, but there may be some spatial-temporal distinction there, and attributed proportions should be calculable - ie that ozone could only account for x, GHG's for y, etc..); increased warming of nights (the trend has not been constant but it's in there)... These two things would not be explained by solar forcing. The increased night warming could be explained by volcanic and anthropogenic aerosols if the forcing is sufficient - ie they do have the quality of cooling days more than nights... Add to that: Svante Arrhenius (spelling?) over 100 years ago (maybe 200?) predicted warming from CO2 increases. James Hansen 1988 - his graph for the forcing scenario most closely matched has thus far stayed close to the temperatures. And: Increased storm activity in the Arctic. Some other circulation changes - there may be evidence of expansion of the Hadley cell, for example. I think evidence of changes in rainfall patterns (space and time, etc.). And: greater warming in the Northern Hemisphere, with especially lower warming in the ocean around Antarctica and in the North Atlantic near Greenland (granted I'm not sure when these predictions were first made but at least for the first part (ocean around Antarctica), it's in a book from 1994. And: simple one-dimensional radiative-convective models from a few decades ago. And: extending the record back even farther with new data, the correlation between CO2 (and CH4) and climate continues. And: glaciers melting around the world - not just Greenland, not just Arctic sea ice, not just Kilomanjaro - and among other tropical glaciers, evidence that it is unusual in the last several thousand years (- that the ice is that old, in other words - yes, ice can flow, but there are some details - that for example, in the ice core, no evidence of melt going back x years, and then the team returns to the site and they find the ice is melting... something like that). And: sea level rising. ocean heat content increasing (that and a number of other things above argue against this all being urban heat islands - that and maybe also the lack of warming in SE U.S. - after all, there are cities there, aren't there - or have they not been growing as fast as other urban areas?). And: both the observations and the theory are a bit unclear on this one, but it does seem like tropical cyclones have been getting more intense - if not more numerous (outside the Atlantic multidecadal cycle)... to be continued...
  49. Volcanoes emit more CO2 than humans
    Since much of what I am about to say applies to the "Arctic sea ice"... , I'm going to post a few comments there now. If after that I haven't covered some of what was brought up here in comments 87-95, I'll come back here.
  50. Volcanoes emit more CO2 than humans
    ... of course, I've never been quite clear on 'global dimming - H2O evaporation' - of course if water is being heated to higher temperature, the tendency is for faster evaporation under the same wind and relative humidity. But there has been global warming along with 'global dimming' (? - according to some comments at "Arctic sea ice..."), so how does decreased solar radiation reaching the surface affect evaporation independently of temperature? Is it analogous to the photoelectric effect - in this case, individual higher energy photons are able to kick off H2O molecules into the air even if the temperature is low (but not too low)? Sounds conceivable, but then again, the absorption of solar radiation is distributed within a depth of water from the surface downward; less so for the shortest wavelengths, red light and solar IR, but I suspect it's a tiny tiny fraction that would be absorbed within a 'molecular layer' or two from the surface.

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