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  1. Thanks very much for this one, Gavin. It comes up all the time on sci.environment and I have written arguments similar but without as good calculations and without the authority you bring to it! This will save alot of time.

    One frustration I have is a lack of references for CO2′s and H2O’s share of the GH effect. I use your “Feedback or Forcing” article and this quote of a quote of an offline text book here.

    Is there not some canonical reference (online) that presents a table such as yours out there? Is the table you did and the method you used as good as it gets? When people come to sci.environment with their 95% (sometimes 99%) I like to ask for a reference but don’t feel like I have a very solid offering of my own.

    Comment by Coby — 21 Jan 2006 @ 11:51 PM

  2. If H2O is not forcing it could not be a feedback.It must be a major contributor to the Greenhouse effect since its concentration in air on average is at least an order of magnitude greater than that of CO2 and it has similar spectral characteristics.

    Comment by Brian Forbes — 22 Jan 2006 @ 5:50 AM

  3. So let’s try to calculate the effect of doubling CO2 using David Archers Modtran 4 model here:
    http://geosci.uchicago.edu/~archer/cgimodels/radiation.html

    To do that we need to look up from ground surface to see the increase of radiation flux (W/m2). So we do two runs as function of pCO2 sensor looking up at 0 km in the 1976 US standard atmosphere. We also use constant Relative Humidity to imply water vapor feedback. leaving the other parameters on the default. A pre-industrial pCO2 of 280 ppmv gives us an output of 257.323 W/m2, the double value 560 ppmv yields 260,526. hence doubling CO2 gives an increase of greenhouse effect / radiation flux of 3,2 W/m2.

    Now let’s get Stefan Boltman’s law out:

    http://www.ldeo.columbia.edu/~kushnir/MPA-ENVP/Climate/lectures/energy/Greenhouse_Effect.html

    expression 5:
    G = sigma Te^4 = (1-A) S / 4

    We can rewrite that as

    Te= ( (1-A) S / 4 sigma)^ ¼

    Substituting A (albedo) = 0,3 and S (solar flux) = 1367.6 and sigma=5.67E-8 we get the well known black body temperature 254.9 K or -18C.

    Since the average temperature is supposed to be 288K or 15,0C we increase the pure flux with Greenhouse flux (GHF), assuming albedo is zero for IR flux, and hence adjusting the relationship as

    Te= ( GHF/ sigma + (1-A) S / 4 sigma) ¼

    To get the 288K, 15.00 C degrees we see that we have to give GHF the value of 150.75 W/m2. So what would the new temperature be when we add that 3,2 W/m2 (GHF=153.95) for doubling CO2 from 280 to 560 W/m2?

    The answer is 15.589C..

    Hence according to your own MODTRAN4 tell us that doubling CO2 under constant relative humidity (positive forcing) gives us a temperature increase of 0.589 C.

    Hans Erren got a similar result: http://members.lycos.nl/ErrenWijlens/co2/howmuch.htm
    dT=0.6833 centigrade for a doubling of CO2

    Now some more about the positive feedback of water vapor. Soden et al developed their idea based on the eruption of aerosol giant Pinatubo and it’s apparent effect on MSU4 (stratosphere temperature) and MSU2LT (lower troposphere). However they failed to test their hypothesis to the other documented (radio sondes) aerosol eruptions of Agung 1963 and El Chinon 1982. That would have shown that stratosphere reaction would fit perfectly but the lower troposphere did not, which does no good to the credibility.

    Alternative calculations of feedback are here also not supporting the positive feedback ideas:
    http://www.aai.ee/~olavi/cejpokfin.pdf
    http://www.aai.ee/~olavi/2001JD002024u.pdf

    Comment by Andre — 22 Jan 2006 @ 5:54 AM

  4. The contrarian seems well qualified to do the calculation he didn’t need Fox news.
    Bob Carter is a Research Professor at James Cook University (Queensland) and the University of Adelaide (South Australia). He is a palaeontologist, stratigrapher, marine geologist and environmental scientist with more than thirty years professional experience, and holds degrees from the University of Otago (New Zealand) and the University of Cambridge (England). He has held tenured academic staff positions at the University of Otago (Dunedin) and James Cook University (Townsville), where he was Professor and Head of School of Earth Sciences between 1981 and 1999.

    [Response:You'd think so.... -gavin]

    Comment by Tom Brogle — 22 Jan 2006 @ 6:56 AM

  5. A few more calculations.

    Playing a bit more with our spreadsheet and see the difference between then (280 ppmv CO2) and now (375 ppmv CO2). The modtran run says: 258.673 W/m3, hence a difference of 1,35 W/m2 with the 280 value (257.323). We run it in the equation increasing the GH factor to 152.1 to find a temperature increase of 0,25 degrees.

    Now how about the irradiation of the sun. What was that again. Look here:

    http://www.space.com/scienceastronomy/sun_output_030320.html

    “…The new study shows that the TSI (Total Solar Irradiance) has increased by about 0.1 percent over 24 years. That is not enough to cause notable climate change, Willson and his colleagues say, unless the rate of change were maintained for a century or more…..”

    Really? now what if we increase the solar irradiance with 0,1 percent in our little formula? Hence S = 1381.3 and hence in the equation (G = 150.75) Te=15,44 C Hmmm A 0,44 degree increase.

    Let’s take G =152,1 again and S =1381.3. Then we get: T = 15,69 or a 0.69 increase. Isn’t it getting rather close with GISS temp and Jones et al?

    Comment by Andre — 22 Jan 2006 @ 11:40 AM

  6. Let me repeat the last sentence of the article.

    “There are innumerable ‘proper’ references to estimates of the climate sensitivity though, and one should indeed hesitate to accept calculations like this example over the mass of peer reviewed studies.”

    Lots of highly qualified people have looked at the issue of climate sensitivity. Their estimates, appearing in peer reviewed literature, fall within a relatively narrow range. One has to be credulous indeed to believe that a random geologist, not specially knowledgeable about the area, or someone making comments in response to this article is going to find something that all these smart people have missed. I know that this sounds like an appeal to authority, but do we really have a choice about that? My experience with research in my own field has taught me that whenever I enter a new field, I have to make all the standard mistakes before I even begin to understand the real issues. Even with a good background in physics and mathematics, it would take me a minimum of three to five years to even get to the point where I could start making mistakes in this field. That is what we have graduate schools for.

    Comment by Leonard Evens — 22 Jan 2006 @ 5:06 PM

  7. Re #6

    I shouldn’t say that climate sensitivity of current models is in a “narrow” range, as the effect of a CO2 doubling is calculated between 1.5 and 4.5 K. Or 1:3. Or the difference between a benign warming and a probable disaster…

    The issue of climate sensitivity was already discussed on RealClimate: different climate models use different sensitivities for the different main forcings. Thus there are questions enough left for discussion.

    [Response: Not so fast. Different models produce slightly different sensitivities for different forcings, mainly related to the forcings' spatial and altitudinal distribution. For instance, solar and CO2 have opposite effects in the stratosphere, black carbon in the tropics from biomass burning has a different effect from anthropogenic black carbon in the mid-latitudes where it interacts more with snow albedo etc. But these are all results, not assumptions - and the differences are not huge. See Hansen et al, 2005 for more details. -gavin]

    Comment by Ferdinand Engelbeen — 22 Jan 2006 @ 6:45 PM

  8. Given that even a 5 or 6 ºC cooling was associated with the huge ice sheets 20,000 years ago, and that 33 ºC cooling would reduce our planet to a near-snowball-like state, a potential increase of 5 to 6% of the natural greenhouse effect is not to be sniffed at… nor dismissed as irrelevent with highly misleading arithmetic.

    That’s Svante’s back of envelope, which is too much. Hansen makes it only 2.7. But this is an eqilibrium sensitivity which has a relaxation period of more than a century. Transient sensitivities (modeled and observed) point to 1 K/2xCO2 or 0.282 K/Wm-2

    (this entry is logged in ukweatherworld)

    Comment by Hans Erren — 22 Jan 2006 @ 7:49 PM

  9. The experts have to find keep faith with the conjecture that CO2 causes Global Warming in order to preserve government grants and keep their jobs.
    No wonder they all agree.
    There are lots of illogicalities cited to support the conjecture on this web site and also in many of the refereed articles that appear in scientific journals.
    Read them with an open mind and you might also be enlightened
    I used to be a convinced believer in antroprogenic GW but the more I’ve studied the more skeptical I have become.

    Comment by Tom Brogle — 22 Jan 2006 @ 8:02 PM

  10. Re #7: This last statement reminds me of Bjorn Lomborg’s claim that he used to be an environmentalist until his study of various environmental problems caused him to see the light. It turned out later that the only evidence Lomborg could produce of his claimed environmentalism was that he had once made a modest cash contribution (of which there was no record) to Greenpeace. In other words, the more likely explanation is that he made up the environmentalist bit since it would be an effective ploy to promote his book.

    Comment by Steve Bloom — 22 Jan 2006 @ 8:56 PM

  11. Re. #9
    Strange, that. My experience is the opposite – the more I’ve studied the more convinced I have become.

    Comment by Stewart Argo — 22 Jan 2006 @ 9:05 PM

  12. re #9

    Given that the current largest funding source of climate science is also the most antagonistic to evidence of AGW (ie the US gov’t), one would expect that any political pressure would be in the opposite direction of what you suggest.

    Comment by Coby — 22 Jan 2006 @ 11:34 PM

  13. Re #12:
    I think most of us would be quite surprised if the scientists reviewing US grant applications for climate science research (those who decide which proposals are funded) were really “…the most antagonistic to evidence of AGW…”.

    Comment by Armand MacMurray — 23 Jan 2006 @ 3:31 AM

  14. Re: #10
    OK, Steve, I’ll bite: which statement in #7 do you feel is self-serving, and most likely untrue?

    Comment by Armand MacMurray — 23 Jan 2006 @ 3:37 AM

  15. Re #7, Gavin’s comment:

    Gavin, indeed I have a tendency to jump to conclusions too fast to follow for other readers. In this case, the difference in general sensitivity for different models is mainly the result of how models treat cloud feedback.

    The difference in individual sensitivities by Hansen is based on different radiative responses in latitude and altitude. But even if this is a result of the GISS model, this largely depends on the assumptions made in the model for e.g. amounts and radiative effect of aerosols, which are far from settled. A recent study by Heald ea. shows that natural VOC induced aerosols above the boundary layer are mostly of natural origin (7:1), and comprise a 2:1 up to >10:1 amount, compared to SOx (SO2+sulfate) aerosols in the 0.5-10 km free troposphere, or 10% of the total aerosol optical depth measured by satellites… Add to that the effect below the boundary layer and the effect of other natural aerosols (natural fires, sea salt, sand dust, DMS, NOx), good for some 38% of the < 1 micron fraction of total aerosols (according to IPCC estimates)…

    Further, Hansen concludes that solar sensitivity efficacy is around 0.92 the efficacy of CO2, while the Hadcm3 model only uses 0.5. I am interested to know what other models use as individual sensitivities…

    [Response: They don't use, they produce... PS. do not use a raw < symbol in comments, it is interpreted as html. Use "& l t ;" instead. -gavin]

    Comment by Ferdinand Engelbeen — 23 Jan 2006 @ 6:56 AM

  16. Re #10&14:

    I suppose that this is a reaction on comment #7 which is deleted?

    I still am an environmentalist, be it less active than end 1960′s when being an environmentalist was very necessary and costed a lot of individual money (compared to the not so bad wages of some rich NGO’s today…). See my short cv here

    Comment by Ferdinand Engelbeen — 23 Jan 2006 @ 7:13 AM

  17. Re #1 Coby, One possibility is this paper by Kiehl and Trenberth.

    Comment by Brian Jackson — 23 Jan 2006 @ 9:07 AM

  18. Re#9: The funding/ ad hominum argument is wearing a bit thin.
    The people who are involved in climate research are intelligent and highly qualified. If they wanted to they could get good jobs in the commercial world. Science does not pay very well. If a scientist would want more money (s)he would change jobs, not manipulate the research.

    Comment by Hans — 23 Jan 2006 @ 9:42 AM

  19. Re: #2, “If H2O is not forcing it could not be a feedback.It must be a major contributor to the Greenhouse effect since its concentration in air on average is at least an order of magnitude greater than that of CO2 and it has similar spectral characteristics.”

    The first sentence is dead wrong. As a result of climate warming, water vapour increases, which is a feedback loop. This is caused by the increased moisture capacity of the atmosphere with increased temperature, as well as warmer oceans, seas, and rivers, which leads to increased evaporation rates.

    Water vapour is a major contributor to the greenhouse effect. That is correct. However, it is a result of the feedback described above which increases water vapour in the atmosphere.

    What is the principal cause of this feedback over the last century-and-a-half? Human activities which produce greenhouse gases, such as CO2, methane, and others!

    What must we do to minimise this feedback loop and prevent long-term catastrophic events in the very near future? Reduce greatly our GHG emissions!

    Comment by Stephen Berg — 23 Jan 2006 @ 11:35 AM

  20. I’ve never really understood why people like to talk about the world without water vapor, because I surely wouldn’t want to live there.

    It seems to me that if one wants to make an apples to apples comparison about the relative importance of different climate forcing factors, then one ought to be looking at their differential impact under modern conditions. In other words, if I increase substance X by 1% in the atmosphere, what is the effective change in radiative forcing (or temperature), either with or without water vapor feedbacks? I’ve never really seen anyone put it in these terms for the modern atmosphere, and I don’t really know why not, though some results on long-term forcing changes do allow one to ball-park the differential effect.

    Is anyone here familiar with literature that compares the effectiveness of various forcing factors in the modern atmosphere under small perturbations?

    Comment by Dragons flight — 23 Jan 2006 @ 11:53 AM

  21. > compares the effectiveness of various forcing factors …

    Lots. Also depends on whether you measure at the source or after mixing.

    http://pubs.giss.nasa.gov/abstracts/2005/ShindellFaluvegiBS.html (mention)
    http://pubs.giss.nasa.gov/docs/2005/2005_Shindell_etal_1.pdf (PDF)

    Comment by Hank Roberts — 23 Jan 2006 @ 2:32 PM

  22. Re #s 10, 14 and 16: Just to clarify, what is now comment 9 was comment 7 at the time I submitted my response. This re-ordering happens sometimes when comments come in almost simultaneously. Just to clarify, generally I feel that someone’s background is irrelevant to the validity of their views on climate *except* when this particular conversion is claimed. Normally, as with Lomborg, there is little evidence to back up such claims.

    Comment by Steve Bloom — 23 Jan 2006 @ 2:50 PM

  23. I think I could make an argument why there’s no gravity on earth. For one thing universal gavity (according to my high school physics course) has to to with mass – the more mass the greater the gravity. Well, dah, the sun has a lot more mass than the earth and would be counterbalancing all of earth’s gavity many times over. Ergo, earth doesn’t have any measurable gavity that would affect us humans. But because we are suffering under the delusion that it does, we obstinantly cling to earth.

    Then, of course, there are birds & airplanes that prove beyond any doubt that earth’s gavity just doesn’t exist, at least not in any significant amount that would affect any of us.

    As for things that come back down to earth when we throw them up in the air, well that’s a matter to them bumping into all those natural & human-emitted GHGs up there & bouncing back.

    Comment by Lynn Vincentnathan — 23 Jan 2006 @ 9:11 PM

  24. Gavin-

    The confusing thing for me is radiatively CO2 has its greatest absorption of IR radiation from about 14 microns to 20 microns wavelength….(which corresponds to -50C and below by wien’s displacement law). The Water vapor bands totally overwhelm the CO2 contribution above -50C….is that correct? So increased CO2 should have it greatest leverage on the climate system in places where the mean temperatures are -50C…which is Antarctica for example. There has been basically no trend there in the last 50 years as CO2 builds up. What gives here?

    Also, in the ice core data, CO2 appears to passively follow the inferred temperature trends through the millenia suggesting
    its concentration follows the glacial to interglacial periods and the increased solubility of the oceans at lower temperatures.

    We all have to remember it is a trace gas….and it has increases 100 ppm in 140 years. Yes that is significant, but enough
    to throw the earth’s climate out of whack?

    Also, has anyone proven the increased absorption of IR radiation from increased CO2? Aren’t there satellites that measure outgoing long wave radiation? Shouldn’t we see less OLR for a given temperature at the surface. If you look at these curves….the higher the temperature in a region, the more OLR. Has anyone actually proven that CO2 is reducing OLR from the surface or lower troposphere for the same temperature? I have never seen this in the literature.
    That would be a smoking gun!

    The water vapor feedback is hard for me to understand. More water vapor eventually will equal more clouds and precipitation which is a sink of water vapor and a therefore primary greenhouse gas. Are we certain that the RH will remain the same? I saw your Mount Pinatubo stuff…interesting but it don’t feel conclusive to me. Also if there is a strong water vapor feedback, then when the CO2 concentrations rose 100 ppm between glacial and interglacial periods, why wasn’t the climate system thrown out of whack? Based on the modelling what is the “breaking mechansim” to keep the earth from becoming like venus?
    I believe this is the precipitation, snowfall and ice accumulations.
    The oceans also are a huge storage house for heat to stablize the climate system and restore balance. I would like to see some proof that CO2 increases are causing less long wave radiation to escape given a certain temperature. That would be neat.

    What about solar forcing? The 20th century has had the highest solar activity in a long time (1000 years?)after a period of a quiet sun during the little ice age. Can’t this recent warming be natural from changes in solar activity?

    Yes I believe the earth has warmed since the 1960s…but before that I think the records are questionable. The satellite record finally is showing some small warming. So i do believe we are on an upswing. It could end abruptly….I wouldn’t be surprised. Can we really say its from anthropogenic causes though? I am not convinced but open to learning more.

    Thanks. Look forward to your reply. I am really curious about this stuff and find your blog very informative!!!

    Comment by Dave Nicosia — 23 Jan 2006 @ 9:17 PM

  25. Re: #2, “If H2O is not forcing it could not be a feedback.It must be a major contributor to the Greenhouse effect since its concentration in air on average is at least an order of magnitude greater than that of CO2 and it has similar spectral characteristics.”

    The second part is also wrong. The IR absorption spectrum of water is very different from CO2. To see this go to http://geosci.uchicago.edu/~archer/cgimodels/radiation.html

    CO2 has two allowed IR absorptions, only one of which is very important for atmospheric processes (the bend at ~650 cm^-1). That is the big absorption you see if you run the calculation at the web site. (Wavenumbers are cm-1) The absorption bands of CO2 are compact, extending ~50 cm-1 on each side for atmospheric conditions. There is no allowed rotational absorption at lower frequencies.

    Now set the CO2 concentration to zero and run the calculation again. Water vapor has an allowed rotational spectrum that extends from ~100 cm-1 to 700 cm-1 or so. That is the hash that you see in the figure. The lines are widely separated, unlike the case for CO2. The hash to the right of the figure at ~1200 cm-1 is the IR spectrum of the H2O bending mode.

    The compact peak at ~1100 cm-1 is from ozone. You can see this by zeroing out the trop and strat ozone.

    Rerun the calculation at ~ 1,2,3,4 km altitude with full O3 and CO2. The reason you see little net absorption at 1 km is that the emission from the relatively warm CO2 and H2O balances the absorption.

    Comment by Eli Rabett — 23 Jan 2006 @ 10:07 PM

  26. Oh yes, one other thing about http://geosci.uchicago.edu/~archer/cgimodels/radiation.html, that I think Andre misses. The surface temperature is fixed for the calculation, thus just holding relative humidity constant does not capture the full effect of any water vapor feedback. To do so, in a quick and dirty way, you have to raise the temperature in the “Ground T Offset Box” This makes quite a difference. If you raise the ground temperature 3 C, the intensity is 269.6 W/m2, an additional ~9 W/m2.

    I REALLY like that site. Thanks again to the Chicago crew for maintaining it.

    Comment by Eli Rabett — 23 Jan 2006 @ 10:24 PM

  27. Re #3

    Doubling the CO2 in Modtran 4 http://geosci.uchicago.edu/~archer/cgimodels/radiation.html creates an atmosphere that radiates more IR to the ground but that atmosphere also radiates LESS IR into space. e.g. looking down at 70km, a doubling of CO2 from 280ppmv to 560ppmv causes the radiation to drop from 260.023W/m2 to 257.197W/m2. The problem now is that the earth is no longer in thermal equilibrium, so even if the earth’s surface did only warm up by 0.589C initially, it is going to keep warming up until it achieves thermal equilibrium. I invite everyone to try Modtran to find what the surface temperature would be that achieves thermal equilibrium.

    Comment by Chris O'Neill — 24 Jan 2006 @ 5:37 AM

  28. BLA BLA, ICE CORES SAY RAPID CHANGE HAPPENS. HOT OR COLD. TOSS A COIN

    WHAT KIND OF PEOPLE SAY: “IF ALL THE ICE MELTED SUDDENLY, SEAS WOULD RISE. THEN GIVE AN ACTUAL NUMBER!?” WITHOUT KNOWING THE IMPACT TO PLATE TECTONICS ON THAT GEOGRAPHIC AREA??. REF: NEW MADRID ZONE STILL MOVING FROM LAST ICE AGE.

    [Response: Please avoid all caps comments in future. They are inappropriately visually loud. Thanks. -Moderator]

    Comment by RON MANZI — 24 Jan 2006 @ 11:15 AM

  29. I wrote a very crude, semi-gray RCM for Earth using a fixed convective adjustment of 6.5 K/km and accounting for 19 spectral bands for H2O, CO2, O3 and clouds. I used the Kiehl and Trenberth (1997) cloud scheme. The model ended when dT/dt for all layers becamse less than 0.001 K. The time step was 1 day, cutting in half after every 500 cycles to ensure convergence. :)

    The first run, with 380 ppmv of CO2, gave a surface temperature of 288.3 K after 525.5 simulated days, with surface illumination 0.489 of incoming visual light, and wound up with a TOA discrepancy of 8.0%.

    The second run, with 760 ppmv of CO2, gave Ts = 294.9 K, 349 days, 0.460 surface illumination and 9.3% I/O discrepancy at TOA. So my surface temperature increase by doubling CO2 alone (no H2O or other feedbacks) is 5.6 K. This is very much on the high side; Houghton (2004) makes it 1.2 K for doubling CO2 alone.

    But if you represent the physics even close to accurately, you get a much huger effect from doubling CO2 than from the (contrarian) calculations above.

    Comment by Barton Paul Levenson — 24 Jan 2006 @ 12:37 PM

  30. Re19
    If H2O wasn’t forcing at a low concentration (Estimated to be between 0.7% and 1.0% at 15 degrees)It woulld not be forcing at higher concentration ( between 0.91 and 1.3% at 19 degrees) You cannot say that CO2 is causing the water vapour to rise. Temperature rises increase both CO2 (released from a warmer sea) and H2O {evaporated from same).
    Water vapour must be the major temperature forcer because it present in air at a much higher concentration than CO2.
    We could theorise that H2O has fed back on itself and but for clouds the earth would have overheated long ago
    Increasing H2O in the air would produce more clouds producing perhaps a negative feedback.

    Comment by Tom Brogle — 24 Jan 2006 @ 4:26 PM

  31. Stewart wrote (#11.) : “Strange, that. My experience is the opposite – the more I’ve studied the more convinced I have become”.

    Same with me, Stewart… although I became convinced six years ago… but I’m still learning. For instance,

    Tom Brogle wrote (#9.) : “The experts have to find keep faith with the conjecture that CO2 causes Global Warming in order to preserve government grants and keep their jobs”. …

    I learned quite a bit in reading at the links and article posted to RC Jan 2, 2006 titled Polar Amplification.

    Reading Polar Amplification motivated me to create spread sheet temperature plots with data at climate stations in Alaska, SD_ND MN_WI MI_IND and WA_OR … (1888-2005).

    After doing all that, and in actually seeing the high latitude warming amplification, the only kind of global warming that could be happening is greenhouse gas driven, in order to explain the amplified warm overnight low temperature observations shown in the data as occurring in higher latitude areas… where low humidity air is transitioning into air with higher humidity levels (H2O GHG). If we were to have global warming from a more intense period of solar radiation, the high latitude warming amplification would not be taking place in that manner.

    The obvious explanation for the GHG driven global warming is the heavy CO2 accumulation in the atmosphere which is being observed and monitored by NOAA CMDL CO2, showing rapid accumulation of CO2 in the atmosphere at sampling points at many measuring sites throughout the world. From my perspective, the case is closed… the primary cause of the rapid global warming in progress is the billions? of tons of CO2 which have been emitted into the atmosphere by our burning of fossil fuels for power generation.

    My surface climate station average temperature plots for AK, the Upper Midwest and the U.S. Northwest are at:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Comment by Pat Neuman — 24 Jan 2006 @ 5:54 PM

  32. Re: #30, “Temperature rises increase both CO2 (released from a warmer sea) and H2O {evaporated from same).”

    CO2 increases are, therefore, both a forcing and a feedback. CO2 is emitted due to human activities, forcing the temperature to rise. As the temperature rises, CO2 is emitted from the oceans, forests, etc., which is a feedback.

    Increasing water vapour concentrations does increase clouds, but only in the situation of temperature increases, the current situation of which is primarily the result of human activities. This may help the Earth keep itself from burning up for the short term. However, clouds also increase incoming longwave radiation, which keeps the heat inside the troposphere, yielding warmer temperatures.

    Comment by Stephen Berg — 24 Jan 2006 @ 6:27 PM

  33. Re #3, specifically to the references to work by the Estonian statistician, O. Karner.

    Karner has been taking single time series of diurnal temperature differences and showing that they act as if they are constrained to return to a fixed value. The statistical properties of this time series are “antipersistent” and may be associated with a feedback in a simple lumped parameter model. This is a purely statistical rather than physical model, and it shows there is a homeostatic process, with a number that can be considered “the feedback”.

    Unfortunately, it appears to me that Karner confuses this mathematical property with the H2O amplification of radiative forcing, a physical quantity with which Karner’s feedback constant has only a distant relationship.

    Indeed, there is an antipersistence in temperature anomalies on Earth, and the mechanism is well-known: radiative equilibration. In this phenomenon, water vapor plays an important role but it isn;t a soliloquy. Thus, when Karner says things like (see http://www.aai.ee/~olavi/2001JD002024u.pdf )

    The revealed antipersistence in the lower tropospheric temperature increments does not support the science of global warming developed by IPCC [1996]. Negative long-range correlation of the increments during last 22 years means that negative feedback has been dominating in the Earth climate system during that period. The result is opposite to suggestion of Mitchell [1989] about domination of a positive cumulative feedback after a forced temperature change

    to my reading he is confused. (I am surprised this text passed review at JGR-A.)

    His subsequent paper ( http://www.aai.ee/~olavi/cejpokfin.pdf ) seems to show increased awareness on the matter:

    Using the H estimates to ascertain the cumulative feedback sign dominating in the Earth climate system for the particular variable. In the present study the term feed-back is used in the sense of total reaction of the variable to customary forcing in the Earth climate system. Such an understanding is unavoidable in statistical analysis of meteorological time series because, as a rule, they are affected by many forcing types including the seasonal and daily cycles in solar radiation. In climatology the term feedback is usually connected to the corresponding feedback loop, e.g ice-albedo feedback [13]. For the whole climate system this means that one has to consider many feedbacks at the same time.

    Karner’s methodology does not separate out specific physical mechanisms but is simply a way of characterizing a time series. It in some sense includes but (as I understand it) in no sense measures the impact of water vapor feedback on radiative equilibrium.

    Comment by Michael Tobis — 24 Jan 2006 @ 8:20 PM

  34. “2005 Was the Warmest Year in a Century”:

    “The year 2005 may have been the warmest year in a century, according to NASA scientists studying temperature data from around the world.

    Climatologists at NASA’s Goddard Institute for Space Studies (GISS) in New York City noted that the highest global annual average surface temperature in more than a century was recorded in their analysis for the 2005 calendar year.”

    http://www.nasa.gov/vision/earth/environment/2005_warmest.html

    Comment by Stephen Berg — 25 Jan 2006 @ 2:26 AM

  35. Re 31
    That is only a local effect (same as medieval optimum} so cannot be global.
    Some of the highest temperature rises are in places where the population has increased over the last century Did you account for this effect in your calculations.
    Why is Antartica coolng?
    Why is the wjnter ice pack around it as extensive now as it was in 1912 (a bad year for ice)?
    Why was Nansen able to sail his ship right up to 79th parallel above the East Siberian Isles in Nov 1893? I doubt that it will be possible in Nov 2006, it certainly wasn’t in Nov 2005.
    Have a look at the crude Sea Surface Temperatures published in Nature in 1995 and you will see that SSTs in 1860 were as high as the were in 1980.
    History does not agree with the CO2 causes GW conjecture.

    Comment by Tom Brogle — 25 Jan 2006 @ 3:00 AM

  36. To qualify the claim in No.34:

    NASA states that the reason their result is higher than others is because they use a different method which includes more weight to the Arctic. This includes an extrapolation of temperature estimates to as much as 1200 km from a station. While they have faith in this method, they state; “in some cases this method can increase error by giving undue weight to one isolated station with anomalous temperature.” NASA aknowledges that results from other eminent groups do not rank 2005 as the highest, and state “the ranking of individual years depends upon differences of only a few hundredths of a degree, which is finer than the accuracy that any method can achieve given observational limitations.”

    This is all in the link.

    Comment by PHEaston — 25 Jan 2006 @ 7:31 AM

  37. Some of the highest temperature rises are in places where the population has increased over the last century Did you account for this effect in your calculations.

    Hi Tom,

    Which places are you thinking of? The most pronounced warming is occuring in the Arctic regions, where there is no urbanization. The Urban Heat Island effect is well studied, very minor and yes, it is accounted for. Check the details of the GISS anaysis here:
    http://data.giss.nasa.gov/gistemp/2005/
    Also look at the global anamoly map and you will see that urbanization is not a good predictor of warming at all. It is pretty clear that UHI can not explain the observed warming trend.

    All that is not even to mention that satellite measurements show similar warming of the troposphere and borehole records also indicate similar surface warming. There is just no credible reason to doubt the surface temperature analysis.

    Whatever website you are reading that is telling you UHI is the cause of a spurious warming trend is either very outdated, very uniformed or very dishonest.

    Why is Antartica coolng?

    I don’t believe this is a correct statement as you have it. What is your source? The continental antarctic AFAIU is showing very little trend, while the peninsula is warming. But as you pointed out regarding someone else’s information, this is regional, the causes will be regional. I believe regional factors in the Antarctic include currents in the Southern ocean and ozone depletion.

    Why was Nansen able to sail his ship right up to 79th parallel above the East Siberian Isles in Nov 1893? I doubt that it will be possible in Nov 2006, it certainly wasn’t in Nov 2005.

    Source? But do you really consider a single anecdote from over 100 years ago to be cause to doubt the millions of temperature measurements we are looking at today? If the “GW alarmists” were telling you such stories with an opposite spin, from long dead Russian sailors, would you find that compelling? The best information about arctic ice is satellite information. Unfortunately we have not had satellites in orbit for long enough to use sea ice extent to confirm the 150 year surface temperature records. But it is notable that for as long as these records exist, they say the same things.

    Comment by Coby — 25 Jan 2006 @ 1:41 PM

  38. To qualify the qualification in 36 to 34 ;)

    NASA also states:

    Record warmth in 2005 is notable, because global temperature has not received any boost from a tropical El Niño this year. The prior record year, 1998, on the contrary, was lifted 0.2°C above the trend line by the strongest El Niño of the past century

    As you say, it’s all in the link! (Though note that my quote came from http://data.giss.nasa.gov/gistemp/2005/)

    Comment by Coby — 25 Jan 2006 @ 1:47 PM

  39. Re#9, okay, skip the science. What’s impressed me is that the ocean has warmed by 1/2 a degree. Now air warming that much doesn’t impress me quite as much as the ocean warming. Do you know how vast all the waters in the oceans are? A half a degree is a really impressive indicator of the earth system absorbing extra heat. I may be wrong, maybe air is a better indicator, but I know in the kitchen, a 12 quart pot of water takes for ever to warm up, much less boil, even while inputting maximum heat from the burner. I think GW denialists should really spend more time in the kitchen.

    As for other arguments–that there is warming, but not from human emitted GHGs–it seems to me all other explanations have been pretty well shot down. At the very least those explanations are no more the likely suspect than A-GHGs. So, it really does behoove us to reduce our GHGs, on the outside chance (as you seem to think) that we are indeed warming our world.

    See, you don’t need to be a rocket scientist or even a climate scientist to figure things out, and what to do about them. And luckily most solutions also save us money! I really think denialists should try a few money-saving solutions, just give them a little try. I assure you you will not regret it. It’ll make you feel good, sort of like you’re cheating Economics 101 – saving money, while doing good to the world.

    Comment by Lynn Vincentnathan — 25 Jan 2006 @ 3:11 PM

  40. In 35: Tom wrote… “That is only a local effect” (#31.) .. “cannot be global”.

    Tom,

    Polar amplification isn’t global, the enhancement is in high lat. areas.

    Furthermore, I didn’t do the calculations, cooperative observers with the NWS did, along with Microsoft Excel software. Furthermore again, Antarctica is not cooling. I pay attention to recent articles, data and reports by Will Steger, polar explorer from Minnesota by dogsled.

    Comment by Pat Neuman — 25 Jan 2006 @ 3:55 PM

  41. Tom — references, please? Assuming you know for sure what you’re saying is true, you can give us links or footnotes so we can find exactly the same thing. If you got it from a second-hand source, give us your source.

    If you don’t have a reference, you’re asking us to check for you whether what you’re posting has facts behind it. Probably it does, but everyone’s got a life, don’t ask us to find your facts based on what you say, eh?

    Comment by Hank Roberts — 25 Jan 2006 @ 4:33 PM

  42. Re #31:

    If we were to have global warming from a more intense period of solar radiation, the high latitude warming amplification would not be taking place in that manner.

    Pat, if the Alaska/Arctic warming was 100% solar driven, this would have the same effect, even more pronounced, as solar has it’s highest effect in the tropics and in the stratosphere (while CO2 effects are more evenly distributed in the troposphere). This causes stratospheric temperature differences which drives planetary waves / jet stream position / rain/clouds more to higher latitudes. And has an effect on the Arctic Oscillation, where warmer/moister air is driven into the Arctic. Thus it is difficult, if not impossible, to say what is attributable to GHG forcing (with feedbacks) and what the part of solar forcing (with feedbacks) in the amplified Arctic warming is.

    The recent warming in the Arctic anyway is not direct from regional CO2, as the observed warming needs a heat/radiation unbalance which is an order of magnitude larger than the direct change in radiation caused by CO2 increases…

    Comment by Ferdinand Engelbeen — 25 Jan 2006 @ 5:52 PM

  43. Ferdinand, in 42 you wrote: “Thus it is difficult, if not impossible, to say what is attributable to GHG forcing (with feedbacks) and what the part of solar forcing (with feedbacks) in the amplified Arctic warming is”.

    It isn’t that difficult, and certainly not impossible, to see the difference between global warming triggered by GHG emissions and global warming initiated by a solar radiation surge. For example, the hot and dry dust bowl years, early 1930s, cannot be attributed to GHG accumulations. If that were true, warmer and more humid conditions would have lasted for centuries, not years.

    Comment by Pat Neuman — 25 Jan 2006 @ 8:42 PM

  44. Re 43,

    Careful here, Pat, you are talking about weather, not climate! There are plenty of predictions of drought in the coming century due to GHG driven warming. On smaller spatial scales and smaller temporal scales (such as ~10 yrs and a portion of the continental US) climatic trends can easily be dominated by regional effects.

    Comment by Coby — 25 Jan 2006 @ 10:53 PM

  45. Coby,

    I don’t see how you interpreted what I said in #43 to be what you said I said, in #44.

    In saying what I said, in #43, I was thinking about what it says below.

    “One look at the graph below shows some interesting results. The first of which is the minima beginning in 1924 and lasting until 1937. This stretch of lower dew points matches well with the dust bowl era when precipitation was also at a minimum”.

    103 Years of Twin Cities Dew Point Temperature Records: 1902-2005
    http://climate.umn.edu/doc/twin_cities/mspdewpoint.htm

    Comment by Pat Neuman — 26 Jan 2006 @ 12:07 AM

  46. Colby,

    I read this article on solar variability by Drew Shindell a few years ago, which may help explain what I was trying to say in #43.

    “Through this coupling, however, solar variability affects the lower atmosphere by changing the distribution of the large amount of energy which is already present. The impact on global average temperature seems indeed to be small; however, changing the flow of energy produces large regional impacts”.

    Solar Variability, Ozone, and Climate
    By Drew Shindell – March 1999
    http://www.giss.nasa.gov/research/briefs/shindell_03/

    I consider weather to be what happens in the short term, less than 90 days. NOAA’s NWS Climate Prediction Center gives “climate” predictions (outlooks) for the U.S. for periods extending to 90 days, 120 days, etc.

    Comment by Pat Neuman — 26 Jan 2006 @ 12:22 AM

  47. Pat, I have always thought climate was much longer term than a few months. I am sure I have seen 30 years thrown around, though I don’t know if there is a consensus definition of this or not. That’s why I thought it was incorrect to infer anything about a climate change, much less what forced it, from a regional drought that was less than a decade.

    I did reread the thread, and I think I still agree with Ferdinand about not being able to seperate solar forcing vs GHG forcing based on regional responses.

    Comment by Coby — 26 Jan 2006 @ 2:19 AM

  48. #43, 45 & 46

    “It isn’t that difficult, and certainly not impossible, to see the difference between global warming triggered by GHG emissions and global warming initiated by a solar radiation surge.”

    You still have not made a case for the above claim. Neither the dust bowl of the 1930′s nor dewpoints in the Twin Cities point to a source of global climate change. If we could look at regional weather or even regional climate and deduce the source of global climate change anyone could be a climate scientist.

    Comment by JohnnyBGoode — 26 Jan 2006 @ 2:42 AM

  49. 42, Ferdinand, Although RC scientists have patiently debunked this solar effect, I repeat myself through 2 pictures in order to reinforce this debunking in near real time, it is hoped that you will appreciate the meaning of this January’s incredibly warm winter (Moscow appears back to normal temperatures now), and contrast it with 2004-05 winter. Your reasoning is that the signal given by much warmer temperatures may not be attributable to CO2, and only solar forcing generated this winter heat wave, rings wrong. On my website look at the news item on the top of the page, the two sun comparison, the one to the left ( early November 2004) shows a huge sun spot, the summer/ fall of 2004 had several sun spots, in large contrast to the summer fall of 2005, almost none were seen, 2005 was a weak year for sun spots. You would probably agree that solar activity was less in 2005, yet 2005 was #1 warmest in history. Go back to the sun disk comparison , the one to the right devoid of sun spots (October 30 2005) taken at the same astronomical elevation, is almost round compared to 2004 shot. You are looking at sun disks penetrating 200 km of high arctic troposphere, and clearly 2005 disk shows by a refraction analysis a less colder atmosphere than 2004. Despite lesser solar activity, it is warmer. So what triggers this warmth? In less than a year… It is likely as explained a combination of gradual GHG heat build up, (ice melting) finally triggering more specific humidity , a greater water vapor presence, especially due to open water of the more open Arctic Ocean Your solar explanation fails and should be put to rest. You may continue defending this idea, I can’t see how given this sun spot conundrum.

    Comment by wayne davidson — 26 Jan 2006 @ 2:49 AM

  50. re #39 Lynn
    Remember that the ocean is heated from the surface, and that warmer waters would have less tendency to sink. Increases in surface temperatures don’t necessarily mean that the bulk oceans have warmed.

    Wouldn’t this in fact be a very slow process anyway? And to get warm water to sink it would have to be very saline indeed. Has anyone done any detailed work on heating of water columns?

    Comment by john mann — 26 Jan 2006 @ 4:30 AM

  51. Ferdinand is right – in GCMs, at least, there is considerable overlap betweent he effects of solar and GHG forcing – at least down here on the surface. Regarding the Dust Bowl, according to Schubert et al, 2004, it was caused by anomalous Pacific SSTs. However, there is no consensus, as far as I know, that this anomaly was caused specifically by solar warming. Certainly, I’m not aware of any study showing this. It may simply have been natural variability – such multidecadal droughts have happened in the past.

    Comment by Tom Rees — 26 Jan 2006 @ 5:18 AM

  52. 47.

    Coby,

    The meaning of “climate” which is used by NOAA’s NWS Climate Prediction Center is much shorter-term than the meaning of “climate” used in discussions on global or regional climate change.
    NOAA/ National Weather Service
    National Centers for Environmental Prediction
    Climate Prediction Center
    http://www.cpc.ncep.noaa.gov/

    Coby, also…

    Regarding your reply: “That’s why I thought it was incorrect to infer anything about a climate change, much less what forced it, from a regional drought that was less than a decade.”,

    I believe that the early 1930s drought and heat wave was extreme in more ways than an absence of rain. The humidity was extremely low across very large regions (Great Plains, Midwest …). There have been other “droughts” in the Midwest which occurred after the dust bowl years. BTW, I didn’t use that term in my reply to Ferdinand in #43, you added the term drought in your comments which followed. Droughts that occurred in the Midwest after the dust bowl years until current (1976-77, 1987-88) have been much less severe than the dust bowl dry period, without the prolonged extremely low humidity in the early 1930s. I’ve made comparisons in Mississippi River monthly flows at Minneapolis for the early 1930s vs other dry periods… the flow on the Mississippi River (used for Minneapolis-St.Paul water supply) was much lower in the early 1930s than other low water years that occurred later in the 20th century. The dust bowl years was a very unusual period of extreme dryness and no clouds. It seems likely to me that the humid warm years, which followed the early 1930s heat and cloudless period, were heavily influenced by prolonged El Nino, ENSO which too place mid-1930s to 1940s, and may have been triggered by the extreme dry hot and clear dust bowl years (which may have been occurring over the ocean, leading to the subsequent El Ninos during the decade that followed the dust bowl years of the early 1930s).

    In my input to public comment on draft U.S. Strategic Plan (18 Jan 2003), http://groups.yahoo.com/group/ClimateArchive/message/2696

    My comments on the draft CSSP Strategic Plan in 2003 included:

    “Please, add: Temperature data by itself is inadequate in monitoring changes in climate. Changes in enthalpy (temperature, humidity, phase change – latent heat exchanges) are very important. It can be misleading to look only at temperature measurements without considering changes in humidity (dewpoints). Near surface humidity is very important in determining the rate of snowmelt, and ice thaw due to the latent heat exchange from the condensation of water vapor on cold surfaces.” … “All dewpoint and relative humidity data from historical records should be made available in digital format for modeling and analysis.”

    I haven’t seen any action taken on the above, which I considered as very important in Jan 2003 (and still do).

    Coby, also…

    After rereading what you wrote: “I did reread the thread, and I think I still agree with Ferdinand about not being able to seperate solar forcing vs GHG forcing based on regional responses”.

    I still disagree with you (and Ferdinand), based on my discussion (above) and based on statements made by Drew Shindell – March 1999, in: Solar Variability, Ozone, and Climate, at:
    http://www.giss.nasa.gov/research/briefs/shindell_03/

    Comment by Pat Neuman — 26 Jan 2006 @ 10:28 AM

  53. In comment #48 by JohnnyBGoode it says: “You still have not made a case for the above claim”.

    The claim I made in my comment #43 to Ferdinand was that: “It isn’t that difficult, and certainly not impossible, to see the difference between global warming triggered by GHG emissions and global warming initiated by a solar radiation surge.”

    It not clear to me what kind of a case Mr. JohnnyBGoode is looking for. I think I have made a case, above. From my experience in hydrologic modeling and prediction, many river gaging sites show a quick surge in flows and levels from local runoff, followed by a more gradual but larger increase in flows and river levels from the larger portion of the river basin further upstream. It takes a sharp eye and focused attention to notice these types of characteristics in physical systems. Also, like increasing river flows, if the rate of rise during the beginning periods of a flood event (or warming climate trend) is much quicker than was earlier expected, it may not be just the timing that’s off. It’s more likely that the volume (or warming maximums) are being underestimated. For example, “David Field, another Scripps researcher who has been working with several Mexican and US colleagues, has found evidence that global warming is beginning to penetrate the ocean today. Dr. Field, now at the Monterey Bay Aquarium Research Institute, and his co-researchers described that warming earlier this month in Science.” http://www.csmonitor.com/2006/0126/p16s01-stss.htm

    Comment by Pat Neuman — 26 Jan 2006 @ 11:04 AM

  54. All the climate models omit a strong negative feedback that only applies to greenhouse warming. Briefly put, a narrowband greenhouse effect will not warm a moist planet because the photons will be shuttled to cover the entire IR spectrum and hence energy will be lost to space through the IR windows. A detailed explanation is given below.

    The absorption coefficient for liquid water as a function of wavelength is given at http://www.lsbu.ac.uk/water/vibrat.html (see the figure near the end). Thermal infrared in the Earth’s atmosphere is around 10 to 20 microns where the absorption coefficient (A) is about 1000 cm-1. For the transmission in liquid water (T), we have

    T = exp(-A*L)

    where L is the depth of penetration. For the case where 1/e or 27% of the incident photons remain unabsorbed and with A=1000 cm-1, then L= 1/1000 cm = 0.01 mm. 98% of the incident photons will be absorbed within 3 times this distance. So one can see from the figure, than practically no infrared photons penetrate beyond 0.03 mm. A more precise estimate of A is 5000 cm-1 at 15 microns where carbon dioxide is emitting radiation, so 0.006 mm is a more accurate number for the depth of penetration of 98% of the photons arising from carbon dioxide forcing. Since the liquid water is such an effective absorber, it is a very effective emitter as well. The water will not heat up, it will just redirect the energy back up to the atmosphere much like a mirror, but not exactly a mirror, and this is an important point.

    For A = 5000 cm-1 at 15 microns, the implied water emissivity is 0.9998 implying that of the incident radiation only 0.02% of it will ultimately be absorbed in the water. The emitted radiation will closely follow a blackbody emission curve whereas the incident flux from carbon dioxide is confined to a band centered at 15 microns. The implication of this is that much of the radiation emitted will escape directly to space through the IR windows, so it could be viewed as a negative feedback. Alternatively, this mechanism implies that climate will be less sensitive to greenhouse gas warming than it would be to an equal solar radiation forcing. In addition, there are many moist areas over land, so this negative feedback or reduction in climate sensitivity may also be operable over portions of the continents.

    The above mechanism works because the initially absorbed infrared energy cannot be transferred to the ocean depths by conduction (too slow), by convection (too small an absorption layer compared to the size of convective cells), or by radiation (too opaque). It must escape by the fastest way possible meaning upwards radiation away from the water.

    Consequently, the only way to explain the ocean heating in depth is for the solar radiation to change and decreasing clouds, as measured by ISCCP, indicate increasing solar radiation is occurring right where the ocean heating is reported to be occurring. The Willis paper does not even mention the ISCCP data that has a similar geographic distribution to the water warming. Simply put, where clouds decrease in amount, the water warms. It has nothing to do with carbon dioxide. A handy plot of the ISCCP results can be found as Figure 3 at http://www.worldclimatereport.com/index.php/2006/01/11/jumping-to-conclusions-frogs-global-warming-and-nature/ where clouds are shown to decrease for 1987-2000. In the Willis paper, Figure 4b, covering 1992-2003, is the one that should be compared to Figure 3. Although the dates do not exactly overlap, the spatial patterns are very similar. There is a need to plot both variables over the exact same time interval, but it is unlikely it would change the major conclusions presented here. Clouds have large natural variations going up and down entirely independent of any greenhouse effect. The climate models do not predict these variations and apparently Willis and others are unaware of these variations.

    [Response: The idea that ocean warming can only occur by SW radiation is erroneous. While SW does penetrate further into the interior, fluxes at the surface (which include sensible and latent heat as well downwelling long-wave) affect the mixed layer equally. The mixing of the upper ocean (to produce the 'mixed' layer) is dominated by the wind (with some buoyancy related effects) and serves to mix surface fluxes of both heat and freshwater over the mixed layer in it's entirety. Clouds both influence and react to sea surface temperatures and correlations between SST and clouds would be expected. The fact remains that the oceans have been warming at a rate of at least 0.6 W/m2 over the last ten years, demonstrating clearly that the planet is out of energy equilibrium - as the climate models suggest. -gavin]

    Comment by Douglas Hoyt — 26 Jan 2006 @ 11:05 AM

  55. In #51, Tom Rees wrote: …

    Posts which I already made earlier this morning in reply to Coby and JohnnyBGoode were counter to the comments which Tom Rees made in #51, thus there is no need for me to reply that I can see now.

    Comment by Pat Neuman — 26 Jan 2006 @ 11:14 AM

  56. Re sunspots — aren’t sunspots COOLER than the rest of the Sun’s surface, since the magnetic field strength is greater in a sunspot and the “molecular” (ion) motions accordingly less random? Please correct me if I’m wrong.

    [Response:Yes. However,that is balanced by the surrounding faculae which are more bright than the sunspots are dark. See some of Judith Lean's papers for details. - gavin]

    Comment by Barton Paul Levenson — 26 Jan 2006 @ 12:10 PM

  57. Gavin,

    One hardly knows where to begin replying to your confused comments in #54. The heating of the ocean will be dominated by solar radiation and lead to the creation of a mixed layer. The mixed layer does not cause the heating.

    Much of the reported ocean warming occurs in areas where there is little or no wind. How could downwelling infrared radiation heat the ocean in such circumstances? In your world view, it could not.

    Your worst mistake is to assume a slow moving mixed layer is a better transport of heat than infrared radiation. The 15 micron radiation is absorbed in a layer much thinner than a human hair. It will escape from that layer by the most efficient means possible, meaning predominantly radiation upwards back to space.

    You really need to think the problem through and it is clear that you haven’t.

    [Response: The confusion is all yours. Solar radiation on it's own is stabilising and would not lead to mixing at all. Even in the climatological average, LW heating is dominant over SW. If such large values of downwelling LW were all being absorbed and re-radiated at the skin layer, the skin SST would be tens of degrees warmer than the mixed layer value. As it is, the differences are around 0.5 deg C at max. The physics of that skin layer can only be explained with significant mixing down into bulk ocean. I suggest you read some of the relevant papers (wick et al, for instance). Your claim that warming occurs in regions with no wind (and presumably no mixed layer?) is completely unfounded. The southern oceans for instance (Gille et al, 2002)? Plenty of wind there! - gavin]

    Comment by Douglas Hoyt — 26 Jan 2006 @ 12:18 PM

  58. #53

    Not only have you been unable to support your claim, but now you claim to be an authority of some sort and jump to a different subject about rivers. Your claim that it isn’t difficult to differentiate between solar driven and GHG driven warming shows a lack of understanding of the complexities of this subject.

    The Shindell paper points to early 20th century warming being driven by solar forcing and it does make the case that the last 3 decades of warming agree with models of GHG driven warming. This is based on models of forcings and their correlation with observed global temperature trends. What the Shindell paper does not do is show the dust bowl of the 1930′s or Twin Cities dewpoints are in any way related to or a sign of specific causes of climate change. Such regional changes do not even provide an accurate picture of global climate and definitely do not point to a specific driver of global climate change.

    Perhaps Gavin could explain this from his science based perspective before people read your comments and wrongly assume that regional weather and/or regional climate is actually an accurate indicator of the drivers behind global climate change.

    Comment by JohnnyBGoode — 26 Jan 2006 @ 12:53 PM

  59. In #58 JohnnyBGoode wrote: “What the Shindell paper does not do is show the dust bowl of the 1930′s” …

    JohnnyBGoode,

    There were no human satellites to even estimate the amount of clear skies and solar radiation over the ocean in the early 1930s. I know from personal observations of lake ice that a clear sky with no snowcover on area lakes can weaken the ice a great deal, even during periods when the air temperature is below freezing. Such was the case in Minnesota and Wisconsin during a recent winter. Lots of snowmobiles, pickups and SUVs went through the ice that year who were not aware of the penetration of solar radiation through clear ice can do to the ice.

    Comment by Pat Neuman — 26 Jan 2006 @ 1:13 PM

  60. Sorry, Gavin, but your arguments are not convincing. For one thing, turbulence is damped close to the surface so any heating of the upper 6 microns cannot be carried lower by turbulence. Conduction cannot compete with radiation in transferring heat out the 6 micron layer. The reason that layer does not heat up is because it is efficiently radiated away. I am not talking about perturbations to the downward longwave radiation over the entire thermal IR spectrum. In that case, perhaps some of your points would have some merit. I am talking about a perturbation in the 15 micron band of the spectrum caused by carbon dioxide. A narrowband perturbation to the downward longwave radiation will be damped as I have pointed out in #54, whereas a broadband perturbation would not be damped. I think all your references are referring to broadband perturbations.

    This will be my last post on this subject.

    Comment by Douglas Hoyt — 26 Jan 2006 @ 1:19 PM

  61. Hi Pat,

    It does not bother me to disagree on the main points we were discussing. I did want to note the following:

    Climate – The average of weather over at least a 30-year period. Note that the climate taken over different periods of time (30 years, 1000 years) may be different. The old saying is climate is what we expect and weather is what we get.

    This is from here, a part of the NOAA site you referenced above. You undoubtably have good reason to have come away with the impression they use a shorter term working definition, but at least officially 30 years seems to be the time frame.

    Comment by Coby — 26 Jan 2006 @ 1:51 PM

  62. More household science, a bit closer to topic. Water vapor really doesn’t stay in the air very long, expecially in cold times; we have to keep refilling our humidifier. Fried fish smell, however, will last for days, long after the steamy effect has ceased (this goes beyond CO2, but that’s as close as I could come, just using bodily senses to estimate effects).

    Another argument (gun-lovers will love), “Guns don’t kill people; people kill people.” Water vapor does not heat the earth (by itself), but the heating that increases the WV heats the earth, & gets WV to help out. The warming causes more retention of water vapor. As we know from my above experiences, that water vapor is constantly vanishing (not into thin air, but back into the solid & liquid environment, I suppose), being replaced by more vapor. I think they refer to it as the hydrological cycle. This is quite natural, & we wouldn’t expect any net increased warming from that.

    So we have to look at what is causing increased water vapor in the atmosphere. Who’s pulling the trigger on the gun? Must be the warming. But if it were only warming from the WV effect, then I’d be able to cook without a heat source — just let the steam effect feedback into heating up my pot.

    So now we’re back to either it’s CO2 (& other forcing GHGs), the sun, or Godzilla who’s heating up the planet.

    Comment by Lynn Vincentnathan — 26 Jan 2006 @ 2:43 PM

  63. Lynn,

    I think I made it pretty obvious (in #31) that the heating up of the planet in recent decades is due to CO2 accumulation in the atmosphere from fossil fuel burning, not the sun. I think Godzilla should be ruled out too.

    Regarding a #58 by JohnnynotBGoode,

    One should note that annual temperatures in Oregon were warmest of record at climate stations in 1934. Thus, dust bowl heat in 1934 extended from the Great Lakes to the west coast, and perhaps out to sea, – a very large “region”.

    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Comment by Pat Neuman — 26 Jan 2006 @ 3:26 PM

  64. Pat (#63), yes, the scientists tell us there has not been any overall increase in solar output, so for now it cannot be blamed for the earth’s warming.

    However, I have to thank the denialists for drawing our attention to the sun as possible source of heating. I suppose solar output could increase in the future and add to our warming woes. Which means we should redouble our efforts to reduce our GHGs (even more than we might need to for AGW) to be on the safe side, just in case the sun starts contributing more heat. Afterall, we can’t do much to turn down solar radiation.

    I’m sure denialists would agree with that – the sun can be a very dangerous thing, be prepared, do what we can do…

    Comment by Lynn Vincentnathan — 26 Jan 2006 @ 4:57 PM

  65. Lynn, I think you’ve been found out – surely a contrarian stooge.

    Comment by EdTed — 26 Jan 2006 @ 6:03 PM

  66. Coby,

    I hope you will forgive the mistake I made in one of my earlier post where I called you Colby instead of Coby. I’m originally from near Green Bay, Wisconsin.

    In #61 you wrote … “Climate – The average of weather over at least a 30-year period”…

    In a post to Pittsburgh IndyMedia Center titled “Winter not coming” I show a plot of annual temperatures at Minneapolis from 1960 to 2005, and a discussion of a change (increase) in the 30 year average or “normal” annual temperature at Minneapolis as the calendar went to the next decade in year 2000. The increase went from an annual temperature of 44.7 F to about 45.3 F, reflecting the average for the latest 30 year period increasing about 0.6 F. Do you want to comment on that?

    However, the main purpose of my Jan 19 post to Pittsburgh IndyMedia Center was to show that annual temperatures at Minneapolis have been above “normal” since 1997. In looking at the right side of the plot at the link below, it really looks strange to me. I’ve notice the same pattern at other stations in the Upper Midwest and Great Plains, showing that what used to be fluctuation about the 10 year trend line is recently showing all at or above it. It also appears that the variance about the mean in recent decades has been decreasing, but I doubt that will continue beyond the next El Nino year (ouch).

    http://pittsburgh.indymedia.org/news/2006/01/22241.php

    Comment by Pat Neuman — 26 Jan 2006 @ 7:03 PM

  67. No problem about the name, Pat, I’ve been called Corby, Toby, Colby, Cody, Cory and even Doby not to mention the numerous phonetically correct mispellings! (Ok, “Doby” was by a 3-yr old, it was very cute :-) But it takes more than that to get under my skin.

    Your indymedia post does raise an interesting point about redefining normal. I have thought about that often listening to weather reports about “N degrees above/below normal today”. I imagine that it is standard practice at all weather bureaus to update the benchmark averages in the face of long term trends. It should perhpas be local news when such an adjustment is made. Surely there is a risk that these long term changes are then forgotten when normality is just redefined, then again we have to put the stick in the sand somewhere!

    What should continue to alert people are the record breaking events. It is a tempting mistake to think that given a steady climate, we should expect to see on average a steady rate of extremes recorded. But actually, every time a new extreme hot or cold is recorded this should reduce the probability of that record being broken again in any given year. Eventually, a record high or low would be extremely rare.

    I don’t know if there have been any studies of the rate of occurence of extremes but this would be an interesting and possibly informative exercise. It would not be surprising though if there is too much uncertainty in individual measurements to draw any conclusions.

    Comment by Coby — 26 Jan 2006 @ 7:39 PM

  68. Coby – “I imagine that it is standard practice at all weather bureaus to update the benchmark averages in the face of long term trends.”

    Indeed it is. See for example http://www.metoffice.gov.uk/climate/uk/averages/index.html where they state as such, and also have 1961-1990 and 1971-2000 averages to compare [no difference maps though!].

    As to your final point, I believe that there was an earlier RealClimate post which touched on the subject of extremes in timeseries data.

    Yes – found it! http://www.realclimate.org/index.php?p=175#more-175
    An interesting read.

    Comment by Timothy — 26 Jan 2006 @ 8:07 PM

  69. #59 #63 Pat Neuman

    You jump from topic to topic but never address the points. This isn’t a contest to see who can submit the most comments to RealClimate.

    We all realize that you can’t back up the claim that it isn’t difficult to see the difference between warming from solar and GHGs. You can’t because it’s simply not true. If it wasn’t difficult you could easily provide scientific references instead of jumping from Oregon weather to no satellites in the 1930′s to SUV’s breaking through the ice in the upper Midwest.

    This topic is complex enough without you making such such unfounded and unsupportable claims.

    Comment by JohnnyBGoode — 26 Jan 2006 @ 8:17 PM

  70. This is for Mr. Mann…..The Fox News “Science Reporter” has been exposed for taking $95,000 from big tobacco, while writing attacks on second hand smokings effects. I believe he was used in the attacks on Mr. Mann. Was he getting checks from big oil too? Here’s the link:
    click here

    Comment by colorado bob — 26 Jan 2006 @ 9:44 PM

  71. re #69

    Johnny,

    It is not difficult for me to see the difference between climate warming from solar and GHGs, as I explained in post #31 and subsequent posts today (all in reply to posts by others – not “a contest to see who can submit the most comments to RealClimate” as you said). It’s like many other things which people do and become good at… after awhile a person develops a knack for what to look for to get the right answer, like putting a 500 piece puzzle together (which I’m no good at because I don’t do 500 puzzles). On the other hand, because I’ve done a lot of looking at what happens in hydrology, my track record on flood predictions has been very good (some have said “almost uncanny”).

    Comment by Pat Neuman — 26 Jan 2006 @ 10:04 PM

  72. I was hoping that somebody could tell me the answer to this question:-

    If humans had all dropped dead from a disease 300 years ago then what would be the current climate trend according to the best climate models? Would things be cooling down or warming up or staying static?

    Comment by Terje Petersen — 26 Jan 2006 @ 10:31 PM

  73. Re 71

    You can see some model hindcasts of the 20th century here: http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm – both with and without anthropogenic forcings.

    They seem to agree that things would have cooled very slightly.

    Comment by Coby — 27 Jan 2006 @ 12:28 AM

  74. re #64 – Lynn and Pat,

    NASA reports show that the Sun is indeed “warmer” than in the past:

    http://aom.giss.nasa.gov/srsun.html

    It is very difficult to overlook this. A slight imbalance in Solar insolation could easily cause a +ve temperature gradient.

    Compare that diagram to the “CO2 as cause of warming” theory.

    To give you a visual perspective, the monitor you are reading this web-site on, is probably set to 1280×1024 which is a bit over 1 million pixels. CO2 is measured at around 330 parts per million, lets scale it up a bit to 400 ppm, since there are > 1m pixels.

    If drawn side by side they would make a line less than a third of the way across one scan line of the display.

    Scattered about the display you would be hard pressed to notice them.

    Faced with this simple logic is it so difficult to see that people would hold contrary views, without needing to label them “denialists” ?

    thanks
    Robert

    Comment by Robert — 27 Jan 2006 @ 1:48 AM

  75. Robert, it’s good to know we have nothing to worry about from bird flu since we are so very much larger (by a much bigger factor than your example) than those pesky little virii. Also, we don’t have to sweat the Iranians getting their hands on a few dozen kilos of highly enriched uranium, since after all such a comparatively tiny amount of material couldn’t make much of an explosion.

    Speaking of proportions, you should perhaps have a look at the scale on the left side of the chart you linked. Also, note that the modern era of direct insolation measurements, roughly since 1950, is pretty flat even on that exaggerated scale, which is to say other forcings have been dominant.

    Comment by Steve Bloom — 27 Jan 2006 @ 4:03 AM

  76. Going back to the very first post in this thread, my layman conclusions on the oft-cited calculations that were rebutted there would be as follows:

    a) The anthropogenic contribution to the current amount of the trace gas CO2 in the atmosphere is not a mere 3% but rather around 30%.

    b) H2O is another, much more abundant, greenhouse element in the atmosphere. But its relative contribution to the greenhouse effect is not as big as that of CO2, and its total contribution does not reach 95% but, at most, 85%.

    c) In the current conditions a better calculation of the global temperature increase due to the anthropogenic portion of atmospheric CO2 could be estimated at around 0.99 °C (3% of 33°C), instead of 0.036 ºC.

    d) There is still scientific discussion on the dimensions and even on the net sign of the other greenhouse elements feedback following the increased CO2 atmospheric concentration but the surface temperature records of the last 3 decades are not inconsistent with a net positive feedback that could be enhanced as the CO2 concentration continues to rise.

    Would everyone agree on these conclusions?

    [Response: Not b). Water vapour and clouds absorb more than CO2, just not as much as the quote claimed. -gavin]

    Comment by Mikel Marielarena — 27 Jan 2006 @ 6:52 AM

  77. Robert: “A slight imbalance in Solar insolation could easily cause a +ve temperature gradient.”

    Indeed. The max change in solar imbalance implied by that graph is ~ 3 Wm^2. This is comparable to the radiative forcing for all GHG [CO2+CH4, etc] to date and is less than the ~4 Wm^2 figure for doubling of CO2 alone.

    I don’t understand why you think the forcing from the sun would be more important than the larger forcing from GHG. The most important difference that I can see is that we can do something about the forcing from GHG, whereas we have not yet mastered control of the sun [although if we really wanted to we could try putting up some kind of parasol to reduce incident solar insolation].

    It’s also worth bearing in mind that the figure you quote has no estimate of the error. There are other historical reconstructions of solar output and they don’t agree.

    I find the contrast with the error estimates given with the much-maligned Mann et al (1999) temperature reconstruction for the past 1000 years [aka "Hockey Stick"] to be quite marked.

    Where does all the sceptics scepticism go when they are faced with data that agrees with their pre-conceived notion that humans aren’t affecting the climate?

    [Response: Note that the forcing from solar needs to be adjusted (for the albedo and geometry) to be comparable to the forcing from GHGs. So for an insolation change of 3 W/m2, the forcing is 3*0.7/4 = ~0.5 W/m2 - much smaller than GHGs (2.4 W/m2 and counting). - gavin]

    Comment by Timothy — 27 Jan 2006 @ 6:54 AM

  78. Just a rather short comment on absorption depth. Evidently the argument that Douglas Hoyt uses has been popularized recently, at least I have seen it a couple of times in the last few days, however, in detail it is wrong.

    The calculation is based on Beer’s law, ln(I/Io) = -sigma N L or, if you prefer the decimal version log10(I/Io) = -A L, where A is the absorbance, and L the length (If you are interested in the first version you understand what N and sigma are, they are related to A fairly simply). The problem with, what I believe originated with Fred Singer, is that when the wavelength of the light exceeds 1/A, Beers law does not work anymore and the situation must be analyzed using Maxwell’s laws. That is the case Hoyt discusses. OTOH, the actual absorption depth even taking this into account, is pretty short, maybe 0.05-0.10 mm at most.

    Comment by Eli Rabett — 27 Jan 2006 @ 10:58 AM

  79. GISS records show the slow cooling of the South pole since 1957. The extent of Antarctic ice in Dec 1914 is detailed in the book “South” by Ernest Shackleton(1919) recently republished (2000). The extent of antarctic ice today can be found at
    https://www.fnmoc.navy.mil/products/SATELLITE/US058SCOM-IMGatp.SPOLE_IC_PS.gif
    Data for Nansen I found with aGoogle search for “fridtjof nansen 1893″The extent of Arctic ice can be found at
    https://www.fnmoc.navy.mil/products/SATELLITE/US058SCOM-IMGatp.NPOLE_IC_PS.gif
    Nansen and Shackleton were not just sailors.There were many sailors sailing the polar regions (mainly south) every year hunting whales, no doubt there were many reports from same but they are not being investigated by climatologists.

    Comment by Tom Brogle — 27 Jan 2006 @ 2:15 PM

  80. Eli Rabett — thank you for the detail, and possible source for the ideas in the absorbtion argument.

    Comment by Hank Roberts — 27 Jan 2006 @ 2:40 PM

  81. RE the warming ocean. I interrupt the angels on pinhead counting to bring you this news from http://www.climateark.org/articles/reader.asp?linkid=51405

    “Earth could warm up fast

    Recent studies of some of nature’s environmental “records” show that global warming can penetrate deep into the ocean faster than scientists have realized. In fact, some such penetration may have already begun…

    Geophysicists call the event the Paleocene/Eocene Thermal Maximum. Several degrees of global warming caused major changes in global ocean circulation patterns. This, in turn, brought warm water into normally frigid deep sea depths. It was accompanied by mass extinctions of bottom-dwelling marine life, according to the fossil record. This massive climate change happened in less than 5,000 years. However, Drs. Nunes and Norris point out that it may have happened even more quickly.

    Commenting on this in the Scripps announcement, Nunes said that the key finding is that “the Earth is a system that can change very rapidly.” The climate change involved a substantial rise in greenhouse gases such as carbon dioxide and methane. Although there was no human input, this is another example of the important role such gases play in climate change…

    There does seem to have been a massive release of methane from the sea bed when warming thawed out frozen methane reservoirs there. This is a hazard in our own time. In the announcement of his group’s findings, Dr. Field said that “changes since the 1970s have been particularly unusual and show that ocean ecosystems in the northeastern Pacific have passed some threshold of natural variability.” “

    Comment by Lynn Vincentnathan — 27 Jan 2006 @ 3:24 PM

  82. re #79

    I’m all for getting data from as many places as possible. I am however, always surprised that the same people who (rightly) wonder about the certainty of the long-term sea surface temperature records because they are based on ship readings for the pre-satellite era will in the same breath point to 100 year old testimonials of polar ice extent.

    Look, sometimes you have to take a step back and look at the whole picture. Are you really trying to say the world is not warming? Are you balancing modern satellite readings, 145 years of direct measurements, borehole analysis, well documented studies of sea ice over the last decades, ocean temperature studies etc, balancing all that against anecdotal accounts of sea ice in specific regions in specific years and concluding that the real trend is cooling?

    Is that what you have learned that caused you to go from being convinced of AGW to being a sceptic?

    Comment by Coby — 27 Jan 2006 @ 3:34 PM

  83. Robert (#74), I wouldn’t call people who speak of increased solar radiation causing warming as “denialists,” only those who do not think our human emitted GHGs can also cause warming. That is, they “deny” that our human emitted GHGs are causing or can cause warming, so the label would be accurate. And they would be “contrarian” in that they go against the bulk of science on this.

    Now let’s hope that somehow the denialists & contrarians are right, the Galileos of our time, because the converse is really quite serious and dangerous. Maybe we’ll all wake up from a bad dream somehow.

    Meanwhile, I’m doing what I can to reduce GHGs, just in case the bulk of scientist happen to be right. In fact, I think they might even be wrong in underestimating the dangers that may lurk ahead, as my previous post suggests scientists didn’t know just how rapidly the oceans can warm.

    Comment by Lynn Vincentnathan — 27 Jan 2006 @ 3:46 PM

  84. There are several issues here. First, it can not be a good thing changing considerably the atmospheric content of CO2 so we should do everything to cut emissions. Second, it’s clear now that temperatures are indeed rising. Third, GH models are the only thing that we do really understand, and they do reproduce some major aspects of Earth’s climate, although there are issues with things like cloud cover that I think are mostly empirically put in models (am I right?). Fourth, people here think that the only issue about the Sun is sunspot number and total energy output. In fact the issue is most likely galactic cosmic ray (GCR) flux, which depends on solar acivity (less GCR during solar maximum) and might have something to do with cloud cover. But solar activity (sunspot number) is not the whole story, the tilt of the sun’s magnetic neutral line affects also the GCR reaching the atmosphere during solar minimum. GCR flux seems to correlate well with the increase in temperature but it may be an accident, people are still trying to find a causal physical mechanism. So pelase do not dismiss the Sun based on sunspot numbers. Unfortunately we probably need another full solar cycle to understand how the Sun affects the climate. The problem is that a solar cycle is 22 years long.

    By the way, these things about the warmest year on record and such always puzzle me. How do we average temperatures for the atmosphere globally? I understand that one can average heat content which depends on local temperature but also on the level of water vapor. How does the average temperature relate with the total heat content of the atmosphere?

    Comment by Caio de Gaia — 27 Jan 2006 @ 5:18 PM

  85. #71 Pat Neuman

    Ok, thanks for the explanation. [rest of comment removed]

    [Response:Please keep comments constructive and focused. -gavin]

    Comment by JohnnyBGoode — 27 Jan 2006 @ 5:22 PM

  86. #85 Gavin’s response

    OK Gavin, could you please explain why Mr. Neuman can make such absurd claims without you ever stepping in?

    Let’s be realistic sir, such comments do more to make this topic look foolish than any contrarian ever could, yet you remain silent. Why?

    And wouldn’t a contrarian who claimed to be able to tell warming was by solar forcing be quickly corrected, if not completely censored? And yet Mr. Neuman’s unfounded opposite claim goes unchallenged?

    I’m sure this comment will also be removed/censored, but at least as you delete it realize that such a biased treatment of comments is noticed by the public at large reading your blog.

    [Response: My editing was a function of your tone, not your content. Feel free to crticise Pat or anyone else, but do it in constructive ways and leave the sarcasm at home. -gavin]

    Comment by JohnnyBGoode — 27 Jan 2006 @ 5:46 PM

  87. Johnny,

    I think I have supported my claims (in earlier comments and in #31. ref: … ” temperature plots for AK, the Upper Midwest and the U.S. Northwest at: http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Re your #58, where your wrote: …”now you claim to be an authority of some sort and jump to a different subject about rivers”. …

    Johnny, I have extensive experience in modeling and prediction of river flows and levels in the Upper Midwest (29 years and six months), and I have a master of science degree from the University of Wisconsin, Madison campus, in hydrology and water resources. I paid my own way through college, and I did not depend on government money until accepting a position in river forecasting in 1976.

    In my understanding, accurate and timely prediction of river flows and levels is done not with physics and math alone, but also with developed understanding and judgment which is acquired by one’s self, and can not be passed on to others by seminars and training, particularly if those wishing to acquire similar operational expertise in hydrology have had little background or have little interest in hydrology. I think the same holds true for understanding climate change. A person must have a will to observe the details which can hide the relationships that are driving climate change. It is not any easier for me to explain how I am able to differentiate between solar driven and GHG driven warming, than it is for me to explain and teach another how I am able to make accurate operational flood predictions. Understanding and judgment need to be acquired by one’s self, in my view.

    Comment by Pat Neuman — 27 Jan 2006 @ 6:55 PM

  88. To Pat Neuman and others with similar convictions.
    I am a hydrogeologist (which includes surface water hydrology). I am experienced in 3D computer modelling (of groundwater flow) and am fully aware that ‘modelling’, while highly useful for understanding the world, can never represent a ‘proof’ – as it is so highly dependent on assumptions. I detest GW Bush and everything he stands for. I believe strongly in protecting the environment (One-car family, with a diesel rather than petrol/gasoline car, recycling most of our waste, etc, and detest SUVs in urban settings). What I request is that you (and others) do not fall into the trap of assuming that those who do not agree with you are either indifferent to environmental protection or in the pay of the ‘right wing oil producers’. My principal concern is that ‘science’ is not distorted by ‘opinion’ or political agenda. Whatever YOU may believe, there remain many who are unconvinced by the case for AGW. I do not have a closed mind which is why I read this site.

    Comment by PHEaston — 27 Jan 2006 @ 7:41 PM

  89. In post #74 it was noted that if 400ppm were viewed on a computer monitor with a million pixels it would be hard to detect on the screen. Please note that the number of molecules in a cubic centimeter of a gas under standard conditions is N = (60.62 ± .03) x 10 to the 22nd power. That is 606200 million million million molecules. There are a lot of molecules of CO2 in that cubic centimeter of air at the ~370 ppmv we have now. So much so that at even 280 ppmv it is observed that the atmosphere is already opaque to outgoing infrared radiation – at the wavelength CO2 absorbs it.

    The CO2 molecule absorbs (and reradiates) infrared radiation at the 15 micron wavelength (700 cycles/cm frequency) bend absorption band most effectively. This band is saturated. Most of the infrared radiation from Earth at this wavelength is retained by the atmosphere and ultimately reradiated toward the ground. The question regarding CO2 then is how does an increase in CO2 add to the heat retained by the atmosphere?

    The answer is that IR absorption can still occur at the edges of the 700 cycles/cm bend absorption band.
    See: http://geosci.uchicago.edu/~archer/PS134/ps134_notes.ch3.pdf

    The absorption of infrared radiation in the wings of the 700 cycles/cm bend band by a doubling of CO2 from 280 ppmv is thus calculated to go up proportionately to the log of the CO2 concentration. This gives us a small number of degrees centigrade elevation in atmospheric temperature – 2º to 5ºC for a doubling of CO2.

    Comment by Tim Jones — 28 Jan 2006 @ 2:57 AM

  90. There are many records of ice extent especially in the Antarctic from whalers (who went there every year} as well as explorers suuch as Shackleton, Nansen. Bruce, Filchner .Amundsen,etc.
    For a description of the pack ice extent in 1914 read “South” by Shackleton (1919) republished in 2000.
    For Nansen and the others I did Google searches. Pesent day ice extent can be found at https://www.fnmoc.navy.mil/products/SATELLITE/US058SCOM-IMGatp.NPOLE_IC_PS.gif
    https://www.fnmoc.navy.mil/products/SATELLITE/US058SCOM-IMGatp.SPOLE_IC_PS.gif
    Tre record of the South polar temp can be found at GISS
    As a child my favourite light reading was polar exploration nowadays it is archeology. The archeology of Greenland indicates that Vikings were livestock and cereal farming in the 12th century about the 80th parallel.
    You say that must have been a local effect but my historical knowledge of Europe Asia and South and Central America indicates otherwise.
    In Australia if you compare temps listed in GISS as rural sites with those at populated sites you can easily infer that the Urban Heat Effect has not been accounted for.
    For the UHI in Alaska see
    http://www.geography.uc.edu/~kenhinke/uhi/

    Comment by Tom Brogle — 28 Jan 2006 @ 6:06 AM

  91. PHEaston,

    I think it’s good that you shared that information with the group (in #88). Outside from this group, my principal concern is the life of young people, especially those trying to make decisions on whether or not to have children. I don’t want to see people be hurt or feel guilty for having brought a loved one into this world and find out too late that the world is falling apart from global warming and diminishing energy.

    On a lighter note, I would appreciate some feedback on the temperature plots which I’ve been adding to:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    For example, I recently added a plot for Dickinson ND for February Mean Daily Air Temperature (1893-2005). February temperatures at all climate stations in the northern Great Plains and Upper Midwest show similar patterns, … a fairly sharp rise and fall during the 1930s-1950s period, a cold period in the 1960s and early 1970s, then increasing temperatures late 1970s to current.

    As I said in earlier posts to RC, I believe that the dust bowl years of the late 1920s to early 1930s were influenced by a surge in solar activity, reflected by very high temperatures and low humidity over the Great Plains and Upper Midwest, and other regions. The warm years continued well beyond the early 1930s. Warm and humid conditions occurred from the mid 1930s to early 1950s, in the Great Plains and Upper Midwest, likely influenced by the moderate to strong El Nino conditions that occurred then, after the hot and dry years of the late 1920s and early 1930s. In “The Grapes of Wrath”, the hot and dry conditions of the early years of the dust bowl, and very wet conditions (CA) later during the 1930s were described.

    It seems likely that the warm ENSO period from the mid 1930s through the 1940s was generated by strong solar activity with very hot and dry conditions in the Great Plains and Midwest in the late 20s to early 1930s.

    As the El Nino warming effects lessened going into the 1950s the temperatures cooled in the northern Great Plains and Upper Midwest, and globally. El Ninos returned in mid-late 1970s, enhanced by increases in anthropogenic warming, making the 1980s and 1990s have strong warming.

    What has many scientists concerned about record global warmth for 2005 is that it came without a strong El Nino. No one is saying much about what the next strong El Nino years may be like, but I wouldn’t be surprised to learn that many scientists are very concerned about that.

    Comment by Pat Neuman — 28 Jan 2006 @ 8:13 AM

  92. To be honest, the first time I read the quote that gave rise to this thread (indeed, from your ‘friend’ Mr. Milloy), I found it rather convincing. It was easy to google out the relative abundance of GH gases in the atmosphere and double-check his assertions.

    However, having read Gavin’s rebuttal, I now find myself much more on his side. The percentage of anthropogenic CO2 in the current atmosphere that Milloy (et al) defends is quite visibly wrong. Still, I’d like to be able to assess how importantly this rebuttal affects the AGW debate. I presume that my personal conclusions on #76 would be acceptable for most anyone, whether contrarians/sceptics or mainstream climatologists. Only Gavin has made a correction to point b that does not seem to be very important in my view.

    With that being the case, I continue thinking that a lot more research should be done, especially to rule out as much as possible the existence of alternative, non-anthropogenic explanations for the observed surface warming of the last 3 decades.

    One of the few certainties that I now have is that, as we speak, money is already running out from my pocket (my country Spain has adhered to the Kyoto protocol). And more importantly, billions of dollars are running out from everybody’s pockets in order to reallocate resources away from market equilibrium points. As an economist, I can guarantee that this will have negative effects on the global economy (less growth, more unemployment). What if in the end the atmospheric concentration of trace gas CO2 is indeed of little importance?

    Some of the questions that I think still demand a conclusive answer are:

    1) Why did surface temperatures cool down from the ’40s through the ’70s, while CO2 and some other GH gases were rapidly growing in the atmosphere?
    2) Why are surface temperature trends not in line with the lower tropospheric ones (as the AGW theory demands)?
    3) Why are temperatures over Antarctica not warming fast, if at all?
    4) What caused previous known global warming events, and particularly the one that began in the mid 19th century? Are we sure that the last decades’ warming is not primarily driven by the same force, whatever it is (and obviously not an anthropogenic GH gases build-up).

    Of course, the idea is NOT to find plausible answers for the above questions (so that observed data do not disturb the AGW theory) but rather to integrate these facts into a theory that explains them better (or prove them wrong, as appropriate).

    If I’m missing something important, I’d love to learn what it is.

    Comment by Mikel Marinelarena — 28 Jan 2006 @ 9:41 AM

  93. I gave my explanation to 1) and 4) posted by Mikel Marinelarena in #92. My answers are in #91 and #31. in this thread, and in reference to plotted monthly and annual average temperature data at U.S. climate stations from 1896 to current within the Midwest, Great Plains, Northwest and Alaska. Please see:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Comment by Pat Neuman — 28 Jan 2006 @ 12:10 PM

  94. Re #92…There has been plenty of research going on to consider alternative explanations of the warming of the last 3 decades and research continues to be done. But, some people seem to want to research forever as a way of avoiding taking action. The scientific community (e.g., as expressed recently by the Academy of Sciences of 11 major countries, including the U.S.) has stated that the science is settled to the point where it is now time to take action. There are always those who won’t buy fire insurance until their house is actually ablaze but that does not make it wise policy.

    Also, the basic physical effects of the forcings due to greenhouse gases are to the point where it is not enough to simply propose an alternative explanation of the current warming. One also needs to provide an explanation of how the feedbacks in the climate system miraculously conspire to cancel out these effects. Some scientists like Richard Lindzen have been desperately trying to provide such explanations but they haven’t panned out.

    In regards to your specific questions–

    (1) GHGs are not the sole driver of climate change. In fact, it is only the latter half of this century that they have become the main driver. (In 1970, the levels of CO2 were still only ~40 ppm above the pre-industrial baseline; now they are ~100 ppm above.) Models run with the best estimates of all natural and anthropogenic forcings reproduce the cooling in the middle of the century (see http://www.grida.no/climate/ipcc_tar/wg1/figts-15.htm ), which I believe is due to a combination of factors both natural and anthropogenic (sulfate aerosol emissions).

    (2) Your information on the lower troposphere temperature trends is out-of-date. See here- http://www.realclimate.org/index.php?p=170

    (3) See here- http://www.realclimate.org/index.php?p=18

    (4) See the graph in my answer to (1). The modeling can reproduce the temperature record from that period but it cannot reproduce the temperature record of the last 30 years without invoking anthropogenic effects. And, again, to actually fully explain the temperature changes of the last 30 years, you not only have to come up with an alternative mechanism to explain the warming, you also have to come up with some mechanism to prevent the GHGs from having their estimated effects on climate from basic physical principles (and more complicated modeling calculations employing the various feedbacks, etc.).

    Comment by Joel Shore — 28 Jan 2006 @ 1:42 PM

  95. Re #90
    Tom,

    I went to the GISS site and generated a global anamoly map. I generated a map setting Mean Period to Annual Jan-Dec for 2000-2005 compared to the default baseline. All the parameters I used can be seen here. I put a gif of the result here. There is no corelation between urbanization and high anamoly in Australia at all. 90% of the population in Australia lives in cities and virtually all are along the coast and widely spaced at that. There is no corelation for Canada either, a country with similarly large disparities in population density (80% of the population lives within 200km of the southern border). Both of these countries should be excellent illustrations of UHI bias if it existed. There is also no correlation in the US, or in Russia, or anywhere.

    Why do you think UHI dominates the global temperature record? Or even just in Australia, which you specifically mentioned?

    Also look at the Antarctic. Some parts of continental Antarctica are warming slightly, some parts are cooling slightly, the peninsula is clearly warming. Your contention that the antacrcic is cooling is clearly an oversimplification at best, more likely just flat wrong. Regardless, this is just one region perhaps dominated by regional mechanisms (currents in the Southern ocean and ozone depletion).

    With regards to your reiteration of anecdotal testimonials of ice extent 100 years ago, I can only note that you did not respond at all to what I wrote in #82 so would just point to it again.

    Comment by Coby — 28 Jan 2006 @ 1:59 PM

  96. I am not denying that warming is occurring I am simply saying
    1) That it must been warmer than it is now in historical times.

    [Response: It *must* have been? Why? - William]

    2) There are indications that the Antarctic was as warm at the begining of the 20th century as it was at the end but that coolng must have occurred sometime in between.

    [Response: I don't know what you mean. Please clarify. There were no direct measurements then - William]

    3) That the Urban Heat Effect has exagerated the Global temperature rise.

    [Response: You want post 43]

    4)That there is something the way that Sea temperature have been treated raise and the way the Hockey Stick denies history raises severe doubts in every one who investigates GW with an open mind.

    [Response:] ?

    Finally a lot of the arguments used in this web site are special pleading such as climatologists are better at statistics than a mining engineer and a economist who have studied statistical methods and I quote
    “The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2″
    There is no DIRECT proof that CO2 causes GW.
    All attempts to find such a proof seem to have failed

    [Response:There is a great deal of work on attribution; the most obvious place to read this is the IPCC TAR, chapter 12 - William]

    Comment by Tom Brogle — 28 Jan 2006 @ 2:53 PM

  97. #92

    With that being the case, I continue thinking that a lot more research should be done, especially to rule out as much as possible the existence of alternative, non-anthropogenic explanations for the observed surface warming of the last 3 decades.

    This is an important area of research. My impression is that it is in no way being ignored and the process of elimination has been going on for decades, the primary cause that can’t be dismissed being CO2. The IPCC TAR has a section on detection and attribution of climate change here you might find interesting.

    1) Why did surface temperatures cool down from the ’40s through the ’70s, while CO2 and some other GH gases were rapidly growing in the atmosphere?

    I believe it is widely accepted that this was the result of a large rise in particulate pollution that was ameliorated by air quality controls.

    2) Why are surface temperature trends not in line with the lower tropospheric ones (as the AGW theory demands)?

    But they are. This discrepancy has been resolved and the models have been validated. See previous RC postings such as this.

    3) Why are temperatures over Antarctica not warming fast, if at all?

    See this RC post.

    4) What caused previous known global warming events, and particularly the one that began in the mid 19th century? Are we sure that the last decades’ warming is not primarily driven by the same force, whatever it is (and obviously not an anthropogenic GH gases build-up).

    Different past changes have had different causes. This is a similar question as your attribution one above. You might want to read some of the IPCC chapter on past climate changes, specifically 2.2 and 2.3 – http://www.grida.no/climate/ipcc_tar/wg1/048.htm

    I don’t think it is correct to say a warming began in the mid 19th century.

    Comment by Coby — 28 Jan 2006 @ 2:54 PM

  98. Re 94
    Look at the individual sites not at the anomaly maps the sites marked rural with no population. These show lower temp rises and in some cases falling temps.

    Comment by Tom Brogle — 28 Jan 2006 @ 3:05 PM

  99. re #95.

    Coby,

    I would like to see references and data used to explain the warming of the late 1920s – late 1940 and the cooling of the mid 1950s – early 1970s (other than the explanation I gave in #31 and #91).

    Comment by Pat Neuman — 28 Jan 2006 @ 3:27 PM

  100. There is a lack of explanations of the greenhouse effect in near real times, present warm winter weather conditions are amazing all experts, and I have not read anything significant, like a proper analysis. I know that winter like air masses are keeping way up North, with no sign of them rushing down South in their usual winter routine. Was this scenario foreseen by any empirical GW model? Would like to know if it was. This is a very significant event, having an eager audience waiting for a plausible explanation.

    I have seen this warm winter coming, I can explain it in terms of a Global conservation of heat, from a very warm summer and fall of 2005, but I leave the details of this greater heat to empirical modellers… Did you replicate this winters planetary waves and weak cold air masses in your models?

    Comment by wayne davidson — 28 Jan 2006 @ 4:24 PM

  101. Help me understand this…

    The earth’s climate in the “short” term (100s of years)
    is basically regulated by CO2 concentration if you
    hold the solar “constant” as constant, assume no significant orbital parameter changes or galactic dust changes, or no volcanic eruptions/meteor impacts.

    So a trace gas of 380 ppm has a huge impact on our climate even though without feedbacks a doubling from pre-industrial levels = .5 to .7K?

    Can someone explain the water vapor feedback again. I just don’t understand how water vapor and clouds are not the dominant GHG.

    I find it amazing that a trace gas can have so much impact on our climate system. Someone please explain.
    thanks

    Comment by David Nicosia — 28 Jan 2006 @ 4:39 PM

  102. http://www.nytimes.com/2006/01/29/science/earth/29climate.html?_r=1&pagewanted=print

    January 29, 2006
    Climate Expert Says NASA Tried to Silence Him
    By ANDREW C. REVKIN

    The top climate scientist at NASA says the Bush administration has tried to stop him from speaking out since he gave a lecture last month calling for prompt reductions in emissions of greenhouse gases linked to global warming.

    … James E. Hansen … said in an interview that officials at NASA headquarters had ordered the public affairs staff to review his coming lectures, papers, postings on the Goddard Web site and requests for interviews from journalists.

    Dr. Hansen said he would ignore the restrictions. “They feel their job is to be this censor of information going out to the public,” he said.

    …. Dr. Hansen said that nothing in 30 years equaled the push made since early December to keep him from publicly discussing what he says are clear-cut dangers from further delay in curbing carbon dioxide.

    In several interviews with The New York Times in recent days, Dr. Hansen said it would be irresponsible not to speak out ….”

    He said he was particularly incensed that the directives affecting his statements had come through informal telephone conversations and not through formal channels, leaving no significant trails of documents.

    Dr. Hansen’s supervisor, Franco Einaudi, said there had been no official “order or pressure to say shut Jim up.” But Dr. Einaudi added, “That doesn’t mean I like this kind of pressure being applied.”

    The fresh efforts to quiet him, Dr. Hansen said, began in a series of calls after a lecture he gave on Dec. 6 at the annual meeting of the American Geophysical Union in San Francisco. …, warning to Dr. Hansen that there would be “dire consequences” if such statements continued, those officers and Dr. Hansen said in interviews.

    George Deutsch, a recently appointed public affairs officer at NASA headquarters, rejected a request from a producer at National Public Radio to interview Dr. Hansen, said Leslie McCarthy, a public affairs officer responsible for the Goddard Institute.

    …. Ms. McCarthy said Mr. Deutsch called N.P.R. “the most liberal” media outlet in the country. … Mr. Deutsch said his job was “to make the president look good”

    Mr. Acosta, Mr. Deutsch’s supervisor, said that when Mr. Deutsch was asked about the conversations he flatly denied saying anything of the sort. …. Mr. Acosta said that for the moment he had no way of judging who was telling the truth.

    … Larry D. Travis, an astronomer who is Dr. Hansen’s deputy at Goddard, …. said he walked into Ms. McCarthy’s office in mid-December at the end of one of the calls from Mr. Deutsch demanding that Dr. Hansen be better controlled….

    Comment by Hank Roberts — 28 Jan 2006 @ 4:53 PM

  103. Pat,

    You can see the forcings involved over the past 150 years as determined by GISS here: http://www.giss.nasa.gov/data/simodel/ There are links to details of each from that page, you may be able to find the actual data from there as well.

    The total forcings for 2000 relative to 1750 are shown here: http://www.grida.no/climate/ipcc_tar/wg1/figspm-3.htm

    Comment by Coby — 28 Jan 2006 @ 5:07 PM

  104. Can someone explain the water vapor feedback again. I just don’t understand how water vapor and clouds are not the dominant GHG.

    Firstly, H2O is the dominant GHG, but it is not a driver of climate change. What makes it a feedback rather than a forcing is the fact that, unlike CO2, if you pump it into the atmosphere, or suck it out of the atmosphere, it will return very quickly to its original levels due to its abundance in the oceans and its ability to quickly rain out. The level of stable H2O concentration is basically a function of air temperature, so that if the temperature rises by whatever means, water vapor will rise as well causing a feedback effect.

    Clouds, AFAIU, are complicated because they can both reflect incoming radiating back into space (cooling) and absorb outgoing radiation, reemitting it back to the surface (warming). They behave this way in different proportions depending on height, type, diurnal cycle, temperature and the size of the particles around which droplets form.

    I find it amazing that a trace gas can have so much impact on our climate system. Someone please explain

    The world is an amazing place! :) Sorry, I have no better explanation than that, but I think you can find countless examples where tiny things can have huge impacts.

    Comment by Coby — 28 Jan 2006 @ 5:42 PM

  105. In 101. David wrote … “Can someone explain the water vapor feedback again. I just don’t understand how water vapor and clouds are not the dominant GHG”.

    David,
    My explanations and projections in climate and hydrologic prediction are based in large part on observations, rather than modeled estimates of what’s happening. The accuracy of models for prediction is dependent on the quality of the input data, the quality of the model and the quality of the parameters derived from model calibration. Thus, model output is too dependent on qualities for me to give large weight to in my predictions. My explanations on the water vapor feedback is not dependent much on models either. I’ve observed CO2 in the atmosphere to be increasing, evidenced by the increase in CO2 at NOAA CMDL measuring stations. I’ve observed winter dewpoints to be increasing. I’ve observed that humid air thaws ice at higher rates than dry air of the same temperature (latent heat of condensation). I’ve observed a rapid decline in the number of weeks per winter/spring that river basins are covered by snow and ice. I’ve observed that soils can dry only after the frozen layer on top has thawed. Therefore, with fewer weeks of winter/spring snow and ice cover, more weeks of evaporation and transpiration take place, adding water vapor to the atmosphere. The difference between warming from increasing “trace” greenhouse gases and warming from solar radiation is the duration of warming from GHGs compared to solar radiation. Solar radiation increases and variation are sporadic and possibly short lived. GHG accumulation is continuous and long lived. If increasing in solar radiation were not sporadic and short lived, it would be difficult to distinguish warming due to solar vs from GHG, but solar doesn’t behave that way… making it pretty easy for me to see the effects from either. The water vapor feedback becomes very important in GHG warming because the warming triggers from GHGs are continuous and long lived.

    Coby,
    re your 102. comments, I have not looked at your suggested websites yet, regarding the warm late 1920s-early 1950s period, and the cooler period from the mid 1950s to early 1970s. I’m hoping that the explanations given at the sites you suggested have data which I can observe, not merely model output which would be too dependent on model quality to be convincing to me.

    Comment by Pat Neuman — 28 Jan 2006 @ 6:15 PM

  106. I really would like to know how the heat content of the atmosphere has been changing. Temperatures are adequate for the public but as a physicist I would prefer true measure of energy change.

    About the topic of the post, the fact that back-of-the-envelope physics should not be applied to climate:

    Qian, Yun; Kaiser, Dale P.; Leung, L. Ruby; Xu, Ming. More frequent cloud-free sky and less surface solar radiation in China from 1955 to 2000. Geophys. Res. Lett., Vol. 33, No. 1, L01812, 10.1029/2005GL024586

    From the abstract:
    “The total cloud cover and low cloud cover have decreased 0.88% and 0.33% per decade, respectively, and cloud-free days have increased 0.60% and overcast days decreased 0.78% per decade in China from 1954-2001. Meanwhile, both solar radiation and pan evaporation have decreased in China, with solar radiation decreasing 3.1 W/m2 and pan evaporation decreasing 39 mm per decade. ”

    This is clearly counterintuitive. The authors attribute this to increased air pollution. It’s the kind of thing that can only be understood in a detailed model.

    There is another paper that shows why is so hard to get decent regional models:

    van den Broeke, Michiel; van de Berg, Willem Jan; van Meijgaard, Erik. Snowfall in coastal West Antarctica much greater than previously assumed, Geophys. Res. Lett., Vol. 33, No. 2, L02505, 10.1029/2005GL025239

    From the abstract
    “the Amundsen Sea sector of West Antarctica and the western Antarctic Peninsula, both data sparse regions, are found to receive 80-96% more accumulation than previously assumed. ”

    The key word here is “data sparse”. It’s a pity, we need models that work well at the regional level. The thing that makes me favor a human cause for GW is the Artic, but I would like to see a model that can predict consistently regional changes everywhere.

    Finally, people only think about the Sun in terms of the “solar constant” (total energy flux) when the biggest impact of the solar activity is possibly in cosmic ray flux. This is still debatable, but I suggest (these are easy to read):

    Marsh, Nigel; Svensmark, Henrik. Solar Influence on Earth’s Climate. Space Science Reviews, v. 107, Issue 1, p. 317-325 (2003).

    de La Fuente Marcos, R.; de La Fuente Marcos, C. On the correlation between the recent star formation rate in the Solar Neighbourhood and the glaciation period record on Earth. New Astronomy, Volume 10, Issue 1, p. 53-66.

    Somewhat harder read, but shows that sunspots are not the only thing to consider when looking into cosmic ray fluxes

    Lockwood, J. A.; Webber, W. R. Intensities of galactic cosmic rays of ~1.5 GV rigidity at Earth versus the heliospheric current sheet tilt. Journal of Geophysical Research, Volume 110, Issue A4, CiteID A04102

    All of this research is still in its early stage, there are people conducting laboratory research in cosmic rays and cloud formation. At this stage they have essentially a series of correlations that may be an accident, but some support for a causal relation may be appearing. The problem is that people starting this research where astronomers and getting cloud people interested has not been easy. The fields had very little previous contact. So please when you dismiss solar activity explain if you are talking about “solar constant” changes or magnetic activity changes.

    Comment by Caio de Gaia — 28 Jan 2006 @ 8:27 PM

  107. > amazing that a trace gas could have so much impact ….

    Those who’ve won Nobel prizes for work in atmospheric chemistry agree — from this page
    http://nobelprize.org/chemistry/laureates/1995/

    read the three speeches linked there for examples.

    In Crutzen’s speech, in particular, he says our life today “… could have been much worse” — how lucky we are, right now.

    Comment by Hank Roberts — 28 Jan 2006 @ 9:05 PM

  108. Thanks. Here is what I am seeing…
    If the earth warms due to solar variability for example, there will be some additional water vapor feedback warming which enhances the initial forcing of the climate system from higher solar output. Now return the sun back to slightly less output…the water vapor feedback works in the opposite sense magnifying the change a bit toward more cooling. But the main point is that the earth returns back to where it was.

    It is the relatively “long” residence time of CO2 in the atmosphere that forces the additional enhanced warming due to the H20 absorption bands. So you force the earth to warm even .5K by GHGs and it gets enhanced by the H20 for a long time. Is there a “breaking” mechanism which slows down the effect of H20. there has to be or every time the earth warms for whatever reason there would be a runaway greenhouse effect. I assume it is more low clouds which leads to a higher albedo and cooling?

    Comment 105 points out that there are observations showing the warming and increasing dewpoints and hence H20 vapor. Is this warming do to C02 increase? How sporadic is solar variability? Can’t the sun increase its output slowly and slightly over 100s of years and with the huge amount of energy storage capacity of the oceans, the warming is showing up in the 20th and early 21st centuries? Could this explain the LIA to the modern warm period? We could be just observing an upswing in climate temperature-wise and the permafrost melting, glacier melting, sea ice retreat, higher dewpoints etc is an artifact of natural warming. With any kind of warming you would have this water vapor feedback which amplifies the forcing signal of the sun’s changes.

    The fact that there was a LIA, a medevil warm period suggests that there is natural variability of the climate. This weakens the hypothesis that changing a trace gas has led to the recent warming trend. And I don’t buy the IPCC’s claim that there was no LIA and medievil warm period. This does not make sense. How can you cool one part of the globe for a couple hundred years and there is no change or little change in the rest of the world given the current continental layout and ocean currents. Heat eventually redistributes itself as the atmosphere becomes well mixed in the long term. So to say that Europe and Greenland were cold for 2 centuries was just local…to me…does not make sense. What about the NAO and the AO? These are Northern hemisphere teleconnection patterns that effect a large part of the NH. Anyway, the LIA makes it confusing for me to believe that GHG increase is the main driving factor in the recent climate changes. It could be mostly natural with some small forcing from C02.

    Is there a smoking gun anywhere that would point to this CO2-H20 synergy leading to the current warming?
    Has anyone measured radiatively changes in absorption bands from spectrometers on satellites showing the combination of these two species leading to more long wave IR downwelling? I would love to see the observed changes in radiative transfer and not have to rely on a model to tell us that this is what is happening. I am a meteorologist and we use computer models all the time and they have so many assumptions and biases. I am leary about a model showing something and then that becomes accepted as an “observation”. It is not. It is just a model. we know the real world is so much more complex that our models.

    Anyway, any radiative transfer evidence of this h20-c02 feedback from satellite data? That would be awesome and would really be a strong case for AGW.

    Comment by David Nicosia — 28 Jan 2006 @ 9:49 PM

  109. I have just arrived at this discussion, and I am disappointed that there was no response to post #3, where Andre demonstrated that a doubling of carbon dioxide will only lead to a 0.6 degree temperature rise, including water vapor feedback. One might think that our increasing carbon dioxide production was no big deal.

    But I do not follow his argument. First, he uses the Modtran program to claim doubling carbon dioxide will lead to a forcing of 3.2 watts per square meter, including feedbacks. This sounds a bit low to me, but I do not understand the meaning of all the parameters in that program. I wonder if Andre understands it, or is his result not valid?

    But then he uses a formula based on this web page to translate the forcing into a temperature change. Please help me here, this does not make sense. They do not mention that an IR absorbing layer radiates at a lower temperature, which is the basis of the greenhouse effect. I suspect the whole thing is rubbish, so Andre’s calculation is invalid. I would appreciate if someone can confirm this.

    Comment by Blair Dowden — 28 Jan 2006 @ 11:51 PM

  110. The first statement of the punching bag quote that the combined effect of terrestrial greenhouse gases is to warm the surface of the Earth by 33 C is basically correct. The second statement that 95% of this warming is produced by water vapor is clearly erroneous. Of the 33 C greenhouse effect, about 10-11 C is due to non-volatile greenhouse gases (i.e., gases that do not precipitate out from the atmosphere for the typical range of atmospheric temperatures). These non-volatile greenhouse gases are CO2, CH4, N2O, ozone, and CFCs. If the Earth’s atmosphere were totally devoid of water vapor, these non-volatile GHGs would support a surface temparature 10-11 C warmer than the -18 C equilibrium baseline (which corresponds to no atmospheric greenhouse effect). The rest of the 33 C greenhouse effect is due to feedback effects of water vapor which is a reaction to the radiative forcing due to the non-volatile GHGs and accounts for roughly half of the 33 C greenhouse effect, and clouds which provide roughly 6-7 C. As a crude analogy, the non-volatile greenhouse gases serve as a “skeleton” upon which vater vapor (and cloud) feedbacks can operate. (A horse without a skeleton upon which its muscles can exert their force would be laying sprawled out flat on the ground.) Accordingly, if the non-volatile GHGs (CO2, CH4, N2O, O3, CFCs) were removed from the atmosphere, the atmospheric water vapor and clouds would precipitate from the atmosphere, and the resulting surface temperature would drop to the baseline -18 C value. In this over-simplified model, the non-volatile greenhouse gases (CO2, CH4, N2O, O3, CFCs) provide an overall radiative forcing of about 11 C. The volatile component (water vapor and clouds) operate in the current climate system with an effective multiplicative feedback factor of 3 which multiplies the applied 11 C forcing to generate the total 33 C terrestrial greenhouse effect.

    An early discussion of radiative forcing and climate sensitivity is given by Hansen et al. 1984 (Climate sensitivity: Analysis of feedback mechanisms. Geophysical Monograph 29, Maurice Ewing Vol 5, AGU, 130-163). This paper compares the radiative forcings due to doubled CO2 and to a 2% increase in solar irradiance, and provides a quantitative analysis of feedback contributions due to water vapor, cloud, lapse rate, and surface albedo changes. The paper shows that while feedback efficiencies of the different feedback processes can be compared linearly, the feedbacks combine in a non-linear fashion. In the Hansen et al. 1984 paper, the radiative forcing due to doubled CO2 was 1.2-1.3 C, with the overall feedback factor in the 3-4 range to produce a 4 C global equilibrium warming. More recent results (Hansen et al. 2005, Earth’s energy imbalance: Confirmation and implications. Science 308, 1431-1435) suggest that the total global feedback effect is in the 2.1-2.3 range giving a 2.7 C global warming for doubled CO2.

    Because of overlapping absorption and saturation effects, the greenhouse contributions of individual contributors depend on their atmospheric context. For example, the radiative forcing due to doubled CO2 in the current atmospheric context is about 1.2-1.3 C (with no feedbacks operating). But removal of the current CO2 amount produces a cooling of more than -7 C (with no feedbacks operating). Analytic formulas that describe the amount of radiative forcing due to different concentrations of atmospheric CO2, CH4, N2O, and CFCs can be found in Hansen et al. 1988 (Global climate changes as forecast by GISS three-dimensional model. JGR 93, 9341-9364). Again, the (applied) radiative forcing is provided by changes in the non-volatile GHGs, aerosols, or solar irradiance. Water vapor, clouds, and snow-ice albedo change in response to the applied radiative forcing and account for the overall global feedback factor which acts to magnify the applied forcing to produce the eventual equilibrium change in global surface temperature

    Comment by Andy Lacis — 29 Jan 2006 @ 1:00 AM

  111. > I am a meteorologist (David Nicosia)
    I know of a David Nicosia who is a meteorologist with the NWS. That you?

    I’m a reader here, not a climate scientist, but I think you’ll find your water vapor questions addressed in the discussion about water vapor — http://www.realclimate.org/index.php?p=142

    Comment by Hank Roberts — 29 Jan 2006 @ 1:37 AM

  112. Blair Dowden wrote in comment #109:
    “I have just arrived at this discussion, and I am disappointed that there was no response to post #3, where Andre demonstrated that a doubling of carbon dioxide will only lead to a 0.6 degree temperature rise, including water vapor feedback. One might think that our increasing carbon dioxide production was no big deal.”

    The answer is found in Archer’s writings:
    http://geosci.uchicago.edu/~archer/PS134/ps134_notes.ch3.pdf

    I don’t think David Archer has set up the Modran 4 model to casually debunk his own assertions. But I too would like to see the refutation through a correct demonstration of the model.

    Comment by Tim Jones — 29 Jan 2006 @ 2:33 AM

  113. David Nicosia wrote in comment #108:
    “Anyway, the LIA makes it confusing for me to believe that GHG increase is the main driving factor in the recent climate changes. It could be mostly natural with some small forcing from C02.”

    Judith Lean wrote:
    http://www.gcrio.org/CONSEQUENCES/winter96/sunclimate.html
    (excerpt)
    “What is known of climate change prior to the Industrial Revolution affords additional insight. The well-documented surface temperature rise since 1850 can be viewed as but the most recent 60 percent of a warming of about 0.8°C since the 17th century (Fig. 3d) http://www.gcrio.org/CONSEQUENCES/winter96/article3-fig3.html, interrupted periodically by volcanic effects. Estimates of Northern hemisphere surface temperatures from 1610 to 1800–during part of the so-called Little Ice Age–correlate well with a reconstruction of changes in solar total radiation–around the time of the Maunder Minimum (Fig. 2c) http://www.gcrio.org/CONSEQUENCES/winter96/article3-fig2.html. This suggests, without proving, a predominant solar influence on climate throughout this 200 year, pre-industrial epoch. The reconstructions of solar radiation and surface temperature shown for these years in Figures 3a and 3d http://www.gcrio.org/CONSEQUENCES/winter96/article3-fig3.html tell of an increase in solar radiation of 0.14 percent and a coincident warming of 0.28°C. If we apply the same implied sensitivity to the period since 1850, the 0.13 percent increase in solar radiation in the last 140 years should have produced a warming of 0.26°C, or about half of that observed.

    If we apply the same relationship to the last 25 years, solar changes can account for less than a third of the warming observed (Fig. 5) http://www.gcrio.org/CONSEQUENCES/winter96/article3-fig5.html .”

    Is there more credible current research on her part or others which overturns this assertion? If not, then only about a third
    of the warming since about 1970 can be attributed to solar forcing and the other two thirds is attributed to AGHG forcing.

    Comment by Tim Jones — 29 Jan 2006 @ 3:06 AM

  114. Re #43:

    Pat, sorry for the delay in response. Sometimes one need do some homework instead of discussing climate change, to keep a balance in one’s marriage…

    About the attribution of solar and GHGs to polar amplification, just have a look at the temperature trends in the NH for the last century in Johanessen ea.. You will see in Figure 1a that small variations in lower latitudes (up to 55N) are fortified in the higher latitudes, and particular in the Arctic over 70N. This is to both sides, in cooler periods as well as in warmer periods. Of particular interest is the 1930-1940 period, where a small increase in temperature of 0-0.2 K in the 30-55N band is accompanied by a 0.8-1.2 K rise in temperature above 75N. That period was mainly solar driven.

    The recent warming is more pronounced, also in lower latitudes, and again fortified in the Arctic. Here we have certainly a mix of GHG warming and solar warming (as you know, the sun in recent decades is more active than in the 1930-1940s), but there is no pattern difference between the mainly solar 1930′s and the mixed warming after 1970, only a difference in amplitude. Thus it is quite difficult, if not impossible, to know what part is solar based and what part is GHG based in the instrumental record.

    Btw, the ECHAM4 models used in Figure 1b,c,d clearly overestimates GHG and aerosol forcing (+ feedbacks) and underestimates solar forcing (+ feedbacks).

    Further, don’t relay too much on regional evidence. Alaska certainly warmed with a (PDO related) jump after 1976. But other regions like Greenland were warmer in the 1930-1940′s, cooling thereafter and only reach the higher temperatures again after 2000.

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 12:16 PM

  115. RE William’s comments on 96
    Clarfying
    There are indications that the Antarctic was as warm at the begining of the 20th century as it was at the end but that coolng must have occurred sometime in between.
    See my post 90
    That the Urban Heat Effect has exagerated the Global temperature see my post 96
    That it must been warmer than it is now in historical times see my post 90
    There is no DIRECT proof that CO2 causes GW
    Attribution is not proof

    Comment by Tom Brogle — 29 Jan 2006 @ 1:20 PM

  116. David N (are you the David Nicosia, meteorologist, who works for the National Weather Service? I can’t find a different one, where do you work as a meteorologist?)

    You quote from 1996 US Gov’t Global Climate Change pages — their current pages are a decade newer, 2005-6, and they invite readers to ask questions right there — why not ask at the source first?

    The first few in their “Doctor Climate” page answer many of your questions about what is known now that wasn’t known a decade ago!

    If you want step by step, track the citations forward in the literature.

    See also here: http://www.columbia.edu/~jeh1/

    I’m trying to point out how to look things up, basically what I do when I find very old information online. Hope this helps you do the same.

    Comment by Hank Roberts — 29 Jan 2006 @ 1:33 PM

  117. re #114

    Ferdinand,

    I think solar radiation was high during the 1920s-1930s, evidenced by a surge in temperatures and very low humidity. The 1940s-mid 1950s were influenced by warm El Ninos. The mid 1950s-mid 1970s were influenced by cool La Ninas. By the late 1970s, the climate was similar to what it would have been without the 1920s-1930s peak solar radiation and subsequent El Ninos-La Ninas, possibly set in motion by the peak solar radiation of the 1920s-1930s.

    Thus, we shouldn’t put any of the blame for the rapid global warming we observe now on any increase in solar radiation. That would incorrect.

    The late-1920s-1930s surge in solar radiation was temporary only. After the 1930s, solar radiation fell back to it’s pre-1920s levels, and have remained nearly constant for 1940s to present. The global warming being observed now is entirely a result of human activity, mostly from GHG emissions (and subsequent global warming feedbacks).

    Thus it is not impossible to know what part of our global warming is solar based and what part is GHG based, it’s very clear to me.

    It would also become clear to some others if they reviewed the referenced temperature plots from 1888 to current within the Midwest, Great Plains, Northwest and Alaska, at:

    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Comment by Pat Neuman — 29 Jan 2006 @ 1:59 PM

  118. Oops, my bad editing in #115, I mangled an attempt and ran together replies to two previous items, sorry for mistake. The link, at least, is good, it’s to Hansen’s articles — the Columbia page. He covers a lot of this.

    Comment by Hank Roberts — 29 Jan 2006 @ 2:11 PM

  119. In #117 Pat wrote:

    “The late-1920s-1930s surge in solar radiation was temporary only. After the 1930s, solar radiation fell back to it’s pre-1920s levels, and have remained nearly constant for 1940s to present.”

    This statement is incorrect. During 1920s to 1930s the Sun was much less active than any other time in the 20th century. Since the 1920s to 1930s solar forcing has increased as the Sun has become more active. In fact following the increase started in the 1940s every solar cycle since has been more active than those relatively calm the 1920s-1930s.

    http://sidc.oma.be/html/wolfaml.html

    And several studies show that solar forcing is still increasing:

    http://www.nasa.gov/centers/goddard/news/topstory/2003/0313irradiance.html

    http://www.fel.duke.edu/~scafetta/pdf/2005GL023849.pdf

    Comment by JimR — 29 Jan 2006 @ 4:10 PM

  120. Re #117,

    Pat, it is unclear to me where you have seen these solar data you mention. Several indices (sunspots, sun cycle length, magnetic AA index) give an increase 1900-1955, a decrease until 1975 and an increase thereafter to the current high level (higher than in the 1930′s, or even the past 8,000 years).
    Just look around for the different observations and the reconstructions of TSI (total solar insolation at the top of the atmosphere). Wikipedia has a good oversight…

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 4:22 PM

  121. The NASA page you link says:
    ” … the inferred increase of solar irradiance in 24 years, about 0.1 percent, is not enough to cause notable climate change, the trend would be important if maintained for a century or more.

    I suppose the sun’s behavior could change. So could ours.

    Comment by Hank Roberts — 29 Jan 2006 @ 4:39 PM

  122. Re #49:

    Wayne, I did write that the even IF the current Arctic warming was 100% solar driven, that would not be distinguishable from the pattern of GHG warming. That doesn’t imply that this is the case. It probably is a mix. And depending of the climate model and the choice made for solar reconstrcution, the increase in global temperature of the past two decades is estimated up to 30% solar driven.
    It is clear that there is a polar amplification of small disturbances in the lower latitudes (and primary in the tropics). That there are record global (and consequential Arctic) high temperatures, while there is no El Nino and we are near a sunspot minimum, points to a longer term warming anyway.

    But IMHO most models underestimate longer term solar sensitivity. For Pat Neuman’s intention too: even if there was no increase in solar output after 1940 (but there clearly was), the intensity is higher than let’s say begin 1900. While air and surface temperatures do follow the sunspot trend rather fast, an average increase need much more time to reach a new equilibrium, due to slow responses of the oceans (30 years for the mixed layer to 1,500 years for the deep ocean overturning), ice cover, glaciers, vegetation,…

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 4:49 PM

  123. Re #121:

    Hank, the NASA underestimates the short-term climate change the “only” 0.1% increase in solar strength causes. According to empirical evidence and interpretations of past cycles, the increase in global temperature of the past two decades is estimated 10-30% by solar strength increase.
    See Scafetti and West.

    [Response:But see this comment by Urs Neu on that paper as well... - gavin]

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 5:03 PM

  124. Re #94- Joel, thanks for addressing all the issues I raised in my post #92. I have read through the links you provided.

    You surely have a point when you say that at some stage action should be taken if evidence is mounting that we face catastrophic events. In such a scenario we couldn’t wait until all scientific uncertainties were resolved. Alright. But are we really at that stage? What specific catastrophes can we be reasonably confident that we’ll suffer (or prevent) if we don’t act (or do act) now? Didn’t the American Academy of Sciences issue a report in the seventies that led Science magazine to conclude in it’s March 1, 1975 issue that a long “ice age is a real possibility”? Would it have been wise then to “take action” in order to prevent the “catastrophic” global cooling ecologists and reputed scientists were announcing?

    [Response: It wasn't Science, and there was no consensus for action - see our post on the Global Cooling myth-gavin]

    In any case, I am against the very costly actions that already ARE being taken. But I believe that that’s not the kind of discussion this forum was designed for.

    Regardless of what politicians are doing now about AGW, I’m sure you will agree that, as I said, much more research should be done in order to eliminate scientific uncertainties and take better informed actions, if necessary. Gavin, for one, didn’t object to point d) in my post #76.

    As for your answers to my questions, I continue seeing a lot of ad-hoc explanations for data that were found not to conform to the AGW theory forecasts. Wouldn’t it be much better to have a scientific theory that, as such, can explain and forecast empiric data in advance?

    1) The models you mention indeed generate graphs that visibly support the AGW theory. But models are as good as relevant and accurate are the data you feed them with. How close are climate modelers to knowing all relevant data that would generate a realistic output of past and future climate? Meterologists still struggle to generate accurate predictions beyond 3-4 days with their models. And some prominent climatologists dismiss current model-based climate predictions altogether, since models can only predict what might happen under a given set of conditions, not what WILL happen in the future.

    2) If I am allowed to give credit to prominent scientists such as Pielke, Craig and Sherwood Idso or (of course) Spencer and Christy my information on the lower troposphere temperature trends is not out-of-date. A difference with the surface trends continues to exist and the anticipated warming of the lower troposphere at a faster pace than the surface fails to be validated by available data, in spite of the efforts dedicated to correct and reanalyse it.
    http://blue.atmos.colostate.edu/publications/pdf/naturecomments.pdf
    http://climate.uah.edu/maps/26yeargraf.jpg
    http://www.co2science.org/scripts/CO2ScienceB2C/data/temperatures/temps.jsp

    3) Again, you give me a link where Eric and Gavin do an excellent job at explaining why data from Antarctica do not behave as expected: “there are very reasonable explanations for the recent observed cooling, that have been recognized for some time from model simulations” and put a lot of faith in their eventually behaving “well”: “In short, we fully expect Antarctica to warm up in the future”.

    4) My understanding of the whole debate is that the basic physical principles that you mention end quite early in this discussion (possibly at the 0.99 degrees C of global warming directly generated by the anthropogenic increase of CO2, as discussed above from Gavin’s explanations) and are followed by very complex relations when all feedbacks are considered. If that were not the case, we wouldn’t have any debate and Seitz, Singer, Michaels, Lindzen, Balling. etc would not be able to generate more attention than, say, creationists would in a debate on paleontology.

    On a side note, you may be surprised to learn that, in fact, there are many countries where there is NO debate on AGW, including quite a few European ones. All relevant mass media adhere to the PC trend and constantly bombard the population with catastrophic predictions purportedly supported by ‘Science’. I have seen global warming gladly related in the media to tornadoes, hurricanes and even tsunamis!! Recently a right-wing newspaper in Spain held a set of 5 online chats with GW ‘experts’. 4 of them were environmental activist and the only scientist (a physicist) turned out to be the local representative of some “Concerned Scientists” association. This gentleman informed us that if we don’t act fast in 100 years the Greenland icecap will melt, which will provoke a 400,000 years long ice-age and that the current global warming is 1,000 times faster than any previous one experienced by the planet: http://www.elmundo.es/encuentros/invitados/2005/09/1670/

    How can vote-dependant politicians take wise decisions in face of such a state of public opinion? Would you really like to see this debate-less situation to generalize to the whole of the world? If I were a climatologist seriously dedicated to AGW research I would indeed be very concerned. Concerned by the dangerous snowball that the way this research is being publicized may provoke in society and economy.

    Comment by Mikel Marinelarena — 29 Jan 2006 @ 5:03 PM

  125. Well the sun seems to be in a spotlight of some sort. Lets go not so far back to 2 prominent years in all time high temperatures, 1998 and 2005, a surprise awaits sun activity adherents, 1998 and 2005 occurred when sun spot activity was at their lowest points. There is no need to strictly go back to the 30′s when things don’t quite work in the 90′s and the 21st century.

    Comment by wayne davidson — 29 Jan 2006 @ 5:19 PM

  126. Coby,

    The link at:
    http://www.grida.no/climate/ipcc_tar/wg1/figspm-3.htm shows very low level of scientific understanding on a small amount of solar forcing for 2000 compared to year 1750.

    The link at: http://www.giss.nasa.gov/data/simodel/ on forcings over the past 150 years determined by GISS does not explain 1880-2005 globally averaged surface temperature plots by NOAA and NASA, nor 1888-2005 climate station plots for the U.S. at:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    The explanation for the warm 1930s, cool 1960s and rapid global warming we see happening now is best explained by the case I made in #117. ie. “The late-1920s-1930s surge in solar radiation was temporary only. After the 1930s, solar radiation fell back to it’s pre-1920s levels, and have remained nearly constant for 1940s to present. The global warming being observed now is entirely a result of human activity, mostly from GHG emissions (and subsequent global warming feedbacks)”. …

    Comment by Pat Neuman — 29 Jan 2006 @ 5:31 PM

  127. Re # 117, how do we know with any accuracy the solar radiation from 1920?

    Comment by David H — 29 Jan 2006 @ 5:51 PM

  128. Re #123 (comment):

    Gavin, thanks for pointing to the response of Urs Neu, as I couldn’t react on that anymore, the topic was already closed.

    Here follows my response:
    There are of course problems with this kind of estimation of solar sensitivity, as the geographical spread of temperature measurements of the oceans before 1955 was not very good. And of course, the ENSO influence is not completely filtered out (but that goes to both sides), neither volcanic. Both influence the amplitude. Despite that, it gives a good indication of solar sensitivity for 11 and 22 year cycles (0.11 K/Wm-2 and 0.17 K/Wm2 resp.). Comparable to earlier work which used completely different methods, by Douglass and Clader (0.10 K/Wm-2 for the 11 yr cycle) and White ea.(0.10 and 0.14 K/Wm-2).

    Further, as already discussed a few times here and on other subjects, this doesn’t include the longer term (over 22 years) response to the increase in solar forcing (+ feedbacks) since begin 1900.

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 6:45 PM

  129. #126 Pat,

    Merely repeating your prior conjecture does not make it correct. You have been given numerous references correcting your hypothesis.

    Solar activity it at a high, it warms the oceans, it warms the atmosphere, this takes time, the themal “momemtum” could carry global temperatures upwards for some time to come.

    Quoting from http://www.fel.duke.edu/~scafetta/pdf/2005GL023849.pdf

    Thus, while the theoretical models approximately
    predict the relative climate sensitivity ratio Z8/Z7 and the
    response time-lag, they seem to disagree from each other
    about the actual climate sensitivity to solar variation and
    significantly underestimate the phenomenological climate
    sensitivities to solar cycles as we have estimated.
    >

    Note that the Leanet al. (1995) diagram, and the others co-graphed at:

    http://www.grida.no/climate/ipcc_tar/wg1/fig6-5.htm

    – Hoyt and Schatten (1993, data updated by the authors to 1999)
    – Solanki and Fligge (1998)
    – Lockwood and Stamper (1999)

    All indicate the same thing, Solar activity is high. The correlation of sunspot activity (2nd order) with solar activity is strong in all of the plots. When sunspot numbers are changing rapidly and/or the numbers of sunpots are high, then solar activity is high.

    As a side note, geometry and albedo effects would reduce the effects of solar activity nearer the poles. The forcing by solar activity would be most prominent nearer the equator, where we are seeing the results.

    IMHO It’s not that GHG are not causing some of the warming, they just don’t do very much. These are trace gases, 400 ppm is a tiny amount, there is no catalytic effect (as for Ozone and CFCs), they are not virii that will reproduce. The effects of CO2 are simply overwhelmed by the “noise” of other effects in the system.

    Comment by Robert — 29 Jan 2006 @ 6:47 PM

  130. Re #126,

    Pat, the scientific understanding of solar forcing is very low, that only points to the fact that there is a lot of discussion and differences in interpretation possible (as good as is the case for aerosols)…

    The IPCC forcing graph, as good as the GISS model forcings only are about forcings, without all positive and negative feedbacks that are typical (and different) for the different forcings, which ultimately lead to climate changes.

    About your last paragraph: if you don’t provide a scientific source for that opinion, then it is your opinion, but not based on any scientific evidence…

    Comment by Ferdinand Engelbeen — 29 Jan 2006 @ 7:00 PM

  131. # 127

    Robert,

    Is this your first post to RC?

    In previous posts to RC, I wrote that when CO2 in the atmosphere is high, effects from other things are overwhelmed by the effect of the high CO2 concentration. When CO2 concentration is low (below 300 ppm) variations in other factors besides CO2 (orientation of the earth, orbital and solar radiation fluctuations, etc… can even trigger ice ages. No need for worry about ice ages any time soon, not with CO2 already high. The worry is from rapid CO2 accumulation and rapid global warming.

    Comment by Pat Neuman — 29 Jan 2006 @ 9:21 PM

  132. Re #108 (“Is there a ‘breaking’ mechanism which slows down the effect of H20. there has to be or every time the earth warms for whatever reason there would be a runaway greenhouse effect.”)

    It is fallacious reasoning to say that the water vapor feedback would necessarily cause a runaway greenhouse effect in the absence of some braking mechanism. To see this, consider the following example: Say that an increase in CO2 causes (without water vapor feedback) a 1 deg rise in temperature. Then let’s suppose that the water vapor feedback due to this 1 deg rise causes an additional 0.5 deg rise. Then the feedback on that feedback causes an additional 0.25 deg rise. And, then a 0.125 deg rise and so on. The point is that you get a converging geometric series with the 1 deg rise in temperature caused by CO2 without feedback being translated into a 2 deg total rise once the water vapor feedback (including all the feedbacks on itself) is fully included.

    Of course, in this simplistic example, I haven’t given any proof that such a convergent series is a realistic assumption for our atmosphere. However, I once did a back-of-the-envelope calculation of a simplistic model of the greenhouse effect with water vapor feedback…and within that simplistic model, one indeed got precisely the result corresponding to the sum of a geometric series! As, I recall the two parameters that determined the strength of the feedback were the increase in water vapor concentration due to an increase in temperature (which I assumed followed the law of keeping the relative humidity constant…in which cause this number was accurately known) and the increase in temperature due to a certain increase in water vapor concentration. I didn’t have a good number for this latter parameter although I seem to recall that the number I would have had to use to get the water vapor feedback magnifying the “bare” warming by a factor of say 2-4 looked reasonable to me.

    Comment by Joel Shore — 29 Jan 2006 @ 10:03 PM

  133. Re #124: In response to your specific numbered comments–

    (1) Well, of course one could always question the models and the inputs to the models. However, the point is that your initial implication that the behavior of the global temperatures in the period from ~1940 to ~1970 has not been explained is not correct. You may not like the explanation…but that is a different thing entirely. As for the 3-4 day prediction thing, you are confusing the prediction of weather and climate…two very different things. There are also independent ways to verify the strength of the feedbacks predicted by the models by looking at past climate changes, such as glacial-interglacial oscillations and responses to volcanic eruptions.

    (2) I don’t think Sherwood Idso is considered to be a serious climatologist by most of the community and the co2science.org site is not a real credible source. And, while Spencer and Christy’s lower troposphere analysis still shows less warming than is measured at the surface, I believe that this difference is barely outside of their error bars. And, other groups that have reanalyzed the data come up with higher numbers. And, the history of Spencer and Christy’s numbers is that they trend higher and higher with time as the years go by, largely because they keep having to make corrections as errors are pointed out to them.

    (4) The reason that Seitz, Singer, Michaels, Lindzen, Balling, etc. generate so much attention probably has more to do with the politics and economic interests than with the science. And, if you think creationism (e.g., intelligent design) isn’t getting much attention, that is only because you are on the wrong (or, more accurately, the right) side of the Atlantic. Here in the U.S., probably more people believe in global warming than believe in evolution and people like Behe who promote intelligent design get lots of attention. In fact, the analogies between in motis-of-operation of the deniers of evolution and the deniers of anthropogenic climate change are strong.

    Comment by Joel Shore — 29 Jan 2006 @ 10:20 PM

  134. In the comment on my post 7
    “But do you really consider a single anecdote from over 100 years ago to be cause to doubt the millions of temperature measurements”
    Look at the Wickepedia definition of anectdotal
    Nansens attempt to reach the N pole in is not anectdotal it a well documented piece of polar exploration.
    Millions of temperature readings weren’t made in the 1890s in polar seas. We have only the witness of Nansen and others as to the extent of the Polar ice cap.
    It appears that the extent is greater now than then.

    Comment by Tom Brogle — 30 Jan 2006 @ 2:43 AM

  135. Re #131, “No need for worry about ice ages any time soon”. Really?

    So far as I can see from the ice core data, after death and taxation another ice age is the next best certainty. The consequences seem so awful I can’t see why we are not worrying about it.

    Can some one tell me if we have climate models that will explain Ice ages? My guess would be that any such model would need a much higher sensitivity for solar forcing than would be convenient for the AGW debate.

    Comment by David H — 30 Jan 2006 @ 8:04 AM

  136. Re #131,

    Pat, have a look at the work of Prof. Fujio MASUDA (Kyoto University), who discovered the 11-year solar cycle in fossil wood from the Cretaceous. You know, a period when CO2 levels were 4-12 times higher than today and global temperatures were 12(-20) K higher.

    Thus even with these high CO2 and temperature levels, the (+/- 0.1 K) solar cycle is detectable and not suppressed.

    [Response: You cannot make a clear attribution to solar - all you can say is that decadal variability is ubiquitos, but there are many sources of decadal varaibility - read Garric and Huber (2003) for instance. - gavin]

    Comment by Ferdinand Engelbeen — 30 Jan 2006 @ 9:20 AM

  137. Re #129

    The solar irradiance reconstructions at http://www.grida.no/climate/ipcc_tar/wg1/fig6-5.htm indicate that average irradiance over the sunspot cycle has increased by about 2W/m2 since the 19th century. This corresponds to an average increase over the whole of the earth’s surface of one quarter of this, or 0.5W/m2. This compares with the forcing produced by the increase in CO2 since the nineteenth century, which can be calculated from the formula quoted by the IPCC to give 1.6W/m2. Thus forcing from anthropogenic CO2 is 3.2 times as much as forcing from increased solar irradiance.

    Comment by Chris O'Neill — 30 Jan 2006 @ 9:22 AM

  138. Re #133

    Joel,

    The reason why I’m not an enthusiast of anthropogenic attributions to all global temperature changes observed on the surface in the 20th century is because some of them are comparable in size to previous known changes (even in Thomas Mann’s reconstruction of the last millennium climate) and obviously those had hardly any anthropogenic origin.

    I am by no means confusing climate with weather prediction. Instead I am contrasting the reliability of computer model simulations in two areas of science closely related.

    I am quite willing to disregard Sherwood Idso’s opinions and the information released on the co2science.org website (that seems to come from 3rd party, independent, sources) if you explain why I should do so. But please bear in mind that certain personal disqualifications work both ways and, more generally speaking, I don’t trust conspiracy-type theories too much. Still, you may be right in your explanation that economic interests and concerns promote attention in the US and a few European countries to the opinions of prominent scientists who don’t agree with AGW (no wonder, I would say).

    Let’s have a look at the debate from a different, simplified perspective. We have a scientific theory (AGW due to increased GHGs) that predicts:

    a) Global warming at a rate of about 0.2 ºC – 0.5 ºC per decade on average, given a business as usual scenario (where Kyoto makes a negligible impact).

    b) A faster warming of the lower troposphere than of the surface.

    c) An amplification of the warming in the polar regions, especially in Antarctica in winter, where the CO2 concentration relative to water vapour is at its highest.

    How well do empiric data validate this theory (which should be applied at least since the 80s, when aerosols are supposed to have stopped cooling the atmosphere)? What empiric data should be produced so that the theory has to be seriously reconsidered?

    [Response: (a) The models "predict" about 0.2 oC/decade, currently, and thats what is observed. Cue the familiar http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm
    (b) Yes: see http://en.wikipedia.org/wiki/Satellite_temperature_measurements (c) You have the science mostly wrong here: see the recent RC post on polar amplification; also my post - William]

    Comment by Mikel Marinelarena — 30 Jan 2006 @ 9:23 AM

  139. Gavin,

    Thanks a lot for the link you gave me in post #124 http://www.realclimate.org/index.php?p=94

    It’s a magnificent job on the state of the climate science in the seventies and a very informative comparison between the global cooling myth prevalent in those days and the current global warming scenario. Looking inside the papers that William reviews and comments it seems apparent that at the time the idea of a coming ice-age was very strong in different media and to different extents managed to make its way inside scientific circles and even into the National Academy of Sciences.

    I was a teenager deeply concerned with environmental issues at the time and, in fact, I happen to remember distinctly the global cooling scare of those days. That was also the time when I began practising mountaineering. In spite of the cooling trend we were supposed to be in, I remember very well that we took it as a fact that mountain glaciers were generally retreating all over the world. As for the Alps and the Pyrenees we had many documents and images from the early explorers (most notably Whimper) that showed a much larger extension of these glaciers in the 18th century.

    Comment by Mikel Marinelarena — 30 Jan 2006 @ 9:49 AM

  140. Re #92 and “1) Why did surface temperatures cool down from the ’40s through the ’70s, while CO2 and some other GH gases were rapidly growing in the atmosphere?”

    Someone later gave the answer as particulate pollution. I’m wondering, would it be correct to think that World War II might have played a significant role? A lot of cities burned, and a lot of the soot must have gone into the stratosphere, which would then cause a slight antigreenhouse effect (the soot warms, the surface cools). Or would it have settled out right away?

    Comment by Barton Paul Levenson — 30 Jan 2006 @ 11:00 AM

  141. re: 140.

    Barton,

    A chart showing radiative forcings, including stratospheric aerosols is at a link which Coby referenced in one of his messages. In reply to Coby I reviewed the charts (second link in 126. below) showing 1) Stratospheric aerosols and 2) Sum of 10 Forcings. The 10 forcing chart shows positive forcings from the 1940s through the 1970s except for a narrow dip (1963-1967).

    126. (repeated below to try to make things easier to follow).

    The link at:
    http://www.grida.no/climate/ipcc_tar/wg1/figspm-3.htm shows very low level of scientific understanding on a small amount of solar forcing for 2000 compared to year 1750.

    The link at: http://www.giss.nasa.gov/data/simodel/ on forcings over the past 150 years determined by GISS does not explain 1880-2005 globally averaged surface temperature plots by NOAA and NASA, nor 1888-2005 climate station plots for the U.S. at:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    The explanation for the warm 1930s, cool 1960s and rapid global warming we see happening now is best explained by the case I made in #117. ie. “The late-1920s-1930s surge in solar radiation was temporary only. After the 1930s, solar radiation fell back to it’s pre-1920s levels, and have remained nearly constant for 1940s to present. The global warming being observed now is entirely a result of human activity, mostly from GHG emissions (and subsequent global warming feedbacks)”. …

    Comment by Pat Neuman â?? 29 Jan 2006 @ 5:31 pm

    Comment by Pat Neuman — 30 Jan 2006 @ 12:58 PM

  142. re #141

    “After the 1930s, solar radiation fell back to it’s pre-1920s levels, and have remained nearly constant for 1940s to present.”

    Once again this information is incorrect. The calmest period of solar activity of the 20th century was the 3 solar cycles from 1900 to 1930, solar cycles 14, 15 and 16. Since that time the Sun has been more active with every one of the 7 solar cycles since that time more active.

    http://sidc.oma.be/html/wolfaml.html

    http://www.gcrio.org/CONSEQUENCES/winter96/article3-fig3.html

    While there isn’t full agreement on increasing solar activity over the last few decades there is complete agreement that solar activity was lower in the early part of the 20th century and beginning in the 1940s rapidly increased and has remained high.

    Comment by JimR — 30 Jan 2006 @ 2:52 PM

  143. Re #138: I agree with you on being leery of conspiracy theories. However, it doesn’t take much of a conspiracy theory to argue that there may be some individual scientists who, while having a scant publication list in refereed journals on the subject of climate change, do have strong political views or economic ties that cause them to have a strong bias. That is why it is best to stick to the peer-reviewed literature or at least sources who have a strong publication record in the peer-reviewed literature on this subject.

    On the other side of the fence (and I am not implying that you fall into this category!!), it does take a very conspiratorial mind to argue, as some do, that the whole field of climate science has been hijacked by a strong bias so that one cannot trust the conclusions of the IPCC, the National Academy of Sciences, or the councils of the AGU {American Geophysical Union) and AMS (American Meteorological Society). [And, even that companies like BP, Shell, and Ford are either part of or duped by the conspiracy (or that they are cowed by the all-powerful environmental movement, as I have seen some argue).]

    Re #139: There are many competing effects in the climate system including (on longer timescales) the natural glacial-interglacial oscillations, as well as the different anthropogenic forcings due to greenhouses gases, soot, and aerosols. Thus, it is understandable that in the 1970s there were concerns expressed both in regards to warming and cooling. However, what is important to note is that the National Academy of Sciences concluded that, given that we still did not have a very good understanding of all of these competing effects, more research was needed rather than taking any specific actions to prevent warming or cooling. That was exactly the right conclusion given the understanding at the time…and their more recent conclusion that it is now time to take action is exactly the right conclusion given our current understanding.

    Comment by Joel Shore — 30 Jan 2006 @ 3:28 PM

  144. re 142.

    Jim,

    The Scientific Basis Working Group I, Climate Change 2001: shows VERY LOW LEVEL of scientific understanding for solar forcing. Justification exists to be skeptical about global warming attributed to variations in solar forcing, even for the late 1920s – 1930s period. How do you explain the record heat and very low humidity from 1927-1936?

    103 Years of Twin Cities Dew Point Temperature Records: 1902-2005
    http://climate.umn.edu/doc/twin_cities/mspdewpoint.htm

    VERY LOW LEVEL of scientific understanding for solar forcing:
    http://www.grida.no/climate/ipcc_tar/wg1/figspm-3.htm

    Comment by Pat Neuman — 30 Jan 2006 @ 4:19 PM

  145. Today in the UK every news bulletin on every radio and TV channel has led with the dire warning from our chief scientist that we have most probably gone past the point of no return and cataclysmic GW is now most likely. We have been treated to clever graphics showing how little of the UK will remain above sea level and pictures showing huge chunks of ice falling off ice sheets into the sea. So maybe we should all go off and do something useful like building boats.

    But why is that that so many are still sceptical and new people keep joining them after the largest sustained media campaign in the history of science?

    Comment by David H — 30 Jan 2006 @ 4:42 PM

  146. re #144

    I agree it’s a good point that the IPCC acknowledges the low level of understanding on the solar contribution. Obviously there is still much to be learned regarding the Sun and climate.

    Regardless of this point I don’t believe you can reconstruct solar forcing from dew points in the Twin Cities. That would be regional climate and solar forcing is reconstructed from the number of sunspots, beryllium-10 and carbon-14 isotopes. All sources agree that the 1920s to 1930s showed a slight lull in solar activity, lower than at anytime since 1940.

    You should seek another explanation for the dry 1920s-1930s in your area.

    Comment by JimR — 30 Jan 2006 @ 7:25 PM

  147. Re #145: Public opinion surveys clearly show the opposite. As has been pointed out with increasing frequency over the last year or so, the debate over whether climate change is happening is done; the task before us now is getting the right public policies in place to deal with it.

    Comment by Steve Bloom — 30 Jan 2006 @ 7:40 PM

  148. Re #141 & #144

    Pat, the “scientific understanding” has to do with the fact that there is not a 100% sure relationship between solar activity indices (sunspots, cycle length, 10Be, 14C and other cosmogenic nucleides, magnetic AA index) and the change in TSI (total solar irradiation), of which we only have accurate data for the last two decades. Even less understanding is how this affects climate, beyond the direct radiation, while there are statistically proven links between solar cycle(s) and climate like cloud cover, jet stream position, precipitation, (sea) surface temperatures,… with effects far beyond the changes in direct forcing.

    Thus lack of scientific understanding is about how large the effect on climate is and what the physical base is for the solar-climate connection. There is no scientific doubt at all that solar activity now is higher than in the 1930-1940′s, or the LIA or even the past 8,000 years. If you aren’t willing to accept this, then further discussion is impossible, as you reject all available scientific evidence, without pointing to any evidence of the opposite view.

    Btw, there is even less scientific understanding about the impact of aerosols, which are the main cause for the 1945-1975 global cooling according to all climate models (but IMHO, by far overestimated)…

    [Response: Not so. There is plenty of scientific doubt about how sunspots, cosmogenic isotopes and magnetic indices are related to irradiance or solar activity in general. That there was a rise (of unknown magnitude) at the start of the 20th century seems probable, that there was a period of reduced activity at the Maunder Minimum (not the LIA in general) is probable, that the activity is higher now (i.e. in 1950) than in the last 8000 years is highly debatable (since it depends on all of those uncertain connections plus problems with tying the satellite obs, to sunspots, to the pre-anthropogenic 14C records). In all of these statements, confidence is low, and new results could overturn them (or reinforce them). Aerosols are indeed similarly uncertain. - gavin]

    Comment by Ferdinand Engelbeen — 30 Jan 2006 @ 7:49 PM

  149. Mikel, what’s your source for your statement:
    “since the 80s, when aerosols are supposed to have stopped cooling the atmosphere)”? Who said that, what basis?

    I looked for that and couldn’t support it. I found:

    Strong present-day aerosol cooling implies a hot future http://www.nature.com/nature/journal/v435/n7046/abs/nature03671.html

    Related article with extensive quotes from several current research articles is here:
    http://scienceweek.com/2006/sw060120-6.htm

    Comment by Hank Roberts — 30 Jan 2006 @ 8:00 PM

  150. Re #136, Gavin’s response:

    Thanks Gavin for the interesting link, which points to several short cycles in the Cretaceous climate, of which the 11-year solar cycle may be visible, or attributed to internal climate cycles… Anyway, that doesn’t change the fact that relative small variations in temperature are visible, even at extreme high CO2 levels and temperatures…

    Comment by Ferdinand Engelbeen — 30 Jan 2006 @ 8:51 PM

  151. Re #137:

    Chris, the IPCC graph gives the forcings, not the feedbacks. In the case of solar forcing, there is an observed statistically significant cloud feedback: a variation of +/- 2% in low cloud cover over the past two sun cycles (see Figure 1 in Kristjansson, and point [11] for a proposal of the physics which may explain the change).

    The reduction of low clouds during the solar high gives a variation of 0.1 K in global SST within a few years. This can go up to 0.3 K in some cycles and up to 0.5 K in the tropics, all within the few years between solar minimum and maximum. The change of +/- 2% in global cloud cover makes a difference of app. +/- 2 W/m2 at the surface, more near the equator, less toward the poles. Thus a strong fortifying factor for the original forcing.

    This is what happened within the last two solar cycles, for which we have rather accurate data for cloud cover, solar radiation and SST’s. More difficult to interpret is what happened before the satellite era. We have several indices for solar activity, but none of them are 100% correlated to solar radiation strength and/or effects on climate. We only know that there is a quite good correlation between them at one side and climate over the pre-industrial period since the Maunder Minimum (sunspots were absent during that period). The estimated impact of the change in solar activity largely depends of which reconstruction you use for solar at one side (0.2-0.6 W/m2 increase since the MM) and which temperature reconstruction you use for the same period (0.2-1.0 K increase since the MM, of which 0.1 K due to volcanoes, the rest is solar).

    Some climate models expect similar changes in cloud cover for increases in GHGs as is the case for solar (thus a positive feedback), but until now, there is no proof for such a relation, and in two climatically important area’s (the tropics and the Arctic), cloud change calculations in current models are proven wrong. See for the tropics Wielicki ea. and Allan and Slingo

    Comment by Ferdinand Engelbeen — 30 Jan 2006 @ 9:08 PM

  152. JimR wrote (#141): “All sources agree that the 1920s to 1930s showed a slight lull in solar activity, lower than at anytime since 1940″.

    The NASA table of “GLOBAL Temperature Anomalies”, GHCN 1880-12/2005 (meteorological stations only) at:
    http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt

    shows that the top five largest positive anamolies for July for the 100 year period from 1880-1979 are:

    1941 .36
    1936 .33
    1940 .31
    1977 .27
    1931 .20

    The NASA data shows that global temperatures from land area stations in the 1930s and early 1940s as shown above were the warmest of record for July up to those dates. Those warm Julys in the 1930s and early 1940s remained the warmest Julys of record until 1981, globally (not local or regional warmth).

    Comment by Pat Neuman — 30 Jan 2006 @ 9:37 PM

  153. This ongoing debate about whether humans are responsible for global warming is really starting to anger me. It matters not who or what is to blame. Global warming is real. We have to start making plans now for the changes that are going to be taking place in the near future. The oceans will rise flooding many of our costal cities. Farmland areas will have to be changed. We need a policy to start preparing for the changes. We do not need to sit around debating who or what’s to blame!

    Comment by scalpmed — 30 Jan 2006 @ 11:22 PM

  154. re 141

    NASA data shows that global temperatures from land area climate stations for 1931 and 1936 were the warmest of record for July up to those dates. http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt

    Comment by Pat Neuman — 30 Jan 2006 @ 11:52 PM

  155. Right on, scalpmed! Adapting to climate change as best we can is the only realistic strategy — assuming we have reached a point of no return, as I believe we have. A panic attempt to do the impossible, i.e, turn our fossil-fuel-based economy around on a dime, is absurd on the face of it — like King Canute commanding the seas to retreat.

    By all means let us work make the world safe for nuclear power, economize on our personal consumption, strive for greater energy efficiency — but let us not kid ourselves. We are also going to have to move to higher ground, build sea walls, use more air-conditioning, and in general build a manifold cultural response to meet the inevitable.

    Comment by Luke Lea — 31 Jan 2006 @ 3:34 AM

  156. Re #144 (2):

    Pat, this may help to reconstruct climate in the Mid-West USA. Abstract from Perry:

    Annual streamflow in the upper Mississippi River Basin demonstrates an apparent connection to annual solar-irradiance variations. The relation is associated with the amount of solar energy available for absorption by the tropical Pacific Ocean and the subsequent effects this stored energy has on mid-latitude atmospheric circulation and precipitation occurrence. The suggested physical mechanism for this relation includes varying solar-energy input that creates ocean-temperature anomalies in the tropical ocean. The temperature anomalies are transported northward by ocean currents to locations where ocean and atmospheric processes can modify jet-stream patterns. These patterns affect jet-stream location and characteristics downwind over North America, which affect the occurrence of precipitation and, ultimately, the amount of streamflow in the upper Mississippi River Basin. The relation provides an opportunity to estimate the annual streamflow of the upper Mississippi River. A multivariate model using solar-irradiance variations and the previous year’s basin precipitation explains nearly one-half of the annual streamflow variability. When data for only La Nina years are considered, the model explains more than two-thirds of the variability since 1950.

    Comment by Ferdinand Engelbeen — 31 Jan 2006 @ 3:40 AM

  157. Re: 147
    Public opinion is fickle – in fact it’s a bit of a herd instinct. Saying the debate is over will not make it so. The real test of public opinions is at the poling stations where people vote in secret. No party here in the UK and I suspect in the US, is likely to get into power on a policy that would make real cuts in CO2 – like doubling the price of petrol and heating oil. When the UK government tried to hike the price of petrol there was a spontaneous revolt amongst drivers that very near brought the county to a standstill and the government was forced into a U turn.

    I must have an exceptional group of friends, family and acquaintances because not one has a considered opinion that AGW is proven to be the main reason for the current warming. The few that believe it is quite openly say that it must be so if the “experts” say so.

    Comment by David H — 31 Jan 2006 @ 5:17 AM

  158. Re #153 and #155,

    The discussion of the relative contribution is important, as that influences the amplitude of the warming in the coming century. Or the difference between a benign warming and a possible disaster.
    No matter the result, we need to look for fossil fuel alternatives asap, even if the contribution of GHGs would be minimal, in any case for geo-political reasons.

    Btw, we have some time to adapt to sea level changes, as getting wet feet from climate change, even in the worst scenario, is not before the end of this century. Storm surge protection (where sea levels may go far higher than for climate induced sea levels in the foreseeable future), also protect to a large extent against sea level changes.

    Comment by Ferdinand Engelbeen — 31 Jan 2006 @ 6:45 AM

  159. Re #148 Gavin’s comment:

    Gavin, as far as I have read in many scientific works, the “consensus” between all solar scientists is that current solar activity is higher than in the Maunder Minimum and higher than in the first halve of the 20th century. That is based on several different types of proxies, of which climate is one of them (for the pre-industrial period). I have not seen any peer-reviewed article that points to a disconnection between sunspots/magnetic activity/nucleides and solar activity/irradiance/(pre-industrial) climate.

    Of course, that can change with new evidence, but the probability that this will happen is comparable to the probability that there is no connection between CO2 levels and IR radiation/climate.

    You are right that the possibility of a solar high compared to the past 8,000 years is more uncertain, as that is based on only one type of proxy.

    Thus the confidence level of increased solar irradiance since the Maunder Minimum (and the first halve of the previous century) is high, but the scientific understanding of the mechanism involved, the amplitude of the change in long-term irradiation and the resulting influence on climate are still very uncertain.

    Comment by Ferdinand Engelbeen — 31 Jan 2006 @ 6:58 AM

  160. Re #138 (answer by William)

    As for a) and b), the Wikipedia report seems quite conclusive on the convergence of surface and tropospheric warming. However the surface warming falls a bit short of the lower predicted margin of 0.2 oC warming per decade and I don’t quite see a conclusive faster warming of the lower troposphere. Of course I am in no position to discuss your or Wikipedia’s assertions. But if I do an always healthy check of alternative sources I surprisingly find things like this: http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/sap1-1prd-exsumfigs.pdf

    In summary, the US Climate Change Science Program tells us in November ’05 that all satellite and radiosonde measurements show a lower warming of the lower troposphere than of the surface, expect for the RSS satellites (but only when compared to HadCRUTv surface estimates): see figure 3. All surface estimates except HadCRUTv also show a rate of warming lower than 0.2 oC per decade for the 1979-2004 period. I find it amazing to find such discrepancies when jumping from one source to another in a field of science such as physics. I always thought that we economists were the experts in torturing data.

    [Response: It looks to me like the wiki page is more up to date than that report. Sadly the page you give doesn't give sources (unlike the wiki page) so its hard to be sure exactly which datasets they are using. You say "Of course I am in no position to discuss your or Wikipedia's assertions" - which is nonsense: everything on that wiki page is carefully sourced, it can all be checked - William]

    As for c), you must be right when you say that I’ve got the science wrong. I just do my best to keep up with a complex discussion out of my area of expertise. But on this particular piece of “science” I followed Christy and Michaels, who must have got it wrong too (sorry, no links available right now).

    [Response: Well, provide the link and you might be more convincing. In the meantime, follow the links I provided... - William]

    Comment by Mikel Marinelarena — 31 Jan 2006 @ 7:28 AM

  161. Re #143

    “On the other side of the fence (and I am not implying that you fall into this category!!)”

    Actually, feel free to call me a sceptic, if you want. But one that is willing to change his mind. I have nothing personal at stake in this discussion and, in fact, I’ve already changed my mind on certain things in this thread after reading Gavin’s first post.

    My personal opinion about scientific biases is that ideology is a much more powerful source of bias than the scant economic corruption cases that there must also exist. But, as I said, this works both ways: for the left/interventionist/ecologist oriented and for the right wing/free-marketers. I gave quite an illustrative example of the former kind in my post #124. Then you also have the “ego factor”. Once a scientist opts to adhere to a side in a heated scientific debate, is he likely to give in unless overwhelmed by incontrovertible data? Given the nature of climate research, that kind of data is particularly difficult to produce, especially in the short or medium term.

    I do not think that you need to posses a conspiratorial mind in order to find reasonable some scientists’ discrepancies with the majority of their colleagues. Do people who adhere to low-carb diets have conspiratorial minds? Do economist who still favour deficit-driven growth policies necessarily believe in conspiracies?

    With all this said, I do confess that I find myself quite uncomfortable challenging the opinion of the majority of climate experts. But it shouldn’t be so difficult to disprove the sceptic scientists’ opinions, if they were nothing but fallacies, should it? And I don’t quite see that happening, sorry.

    Comment by Mikel Marinelarena — 31 Jan 2006 @ 10:13 AM

  162. re 160. Mikel Marinelarena wrote … “In summary, the US Climate Change Science Program tells us” …

    Mikel, a few questions…

    Do you the name of the person directing the US Climate Change Science Program? Was it the same person as in Jan 2003? Excerpts from Jan 2003 public comments on a U.S. climate change plan follow. Do you know why it is than none of the public comments seem to have been used in the final plan that came out in the summer of 2003? How do the various plans relate to each other?


    Public comment excerpts on draft U.S. Strategic Plan for the Climate Change Science Program (CCSP) – 18 Jan 2003

    STATE OF CALIFORNIA
    “The state of California takes climate change quite seriously. We are concerned about the potential costly impacts of climate change on water, energy, and other key economic and environmental systems in the state. In recent decades, for example, stream flow records show a trend toward earlier snowmelt in the principal water supply for the state, the snow pack for the state, the snow pack of the Sierra Nevada: a likely early manifestation of climate change. ” …

    NOAA’s CLIMATE MONITORING AND DIAGNOSTICS LABORATORY (NOAA-CMDL)
    “We need to make clear to all readers what is certain”. … “We know that major greenhouse gases are increasing in the atmosphere over the past century at rates higher than anytime in the historical record. We know that the increase in CO2 is related mostly to fossil fuel emissions. We know that a diverse group of global models cannot replicate the 20th century increase in temperature without involving the observed greenhouse gases.”

    SIERRA CLUB (Craig)
    “Human-forced global climate change is a problem of steadily growing importance that calls for responsible action now. There is so much momentum inherent in the several components of the Earth system that respond to greenhouse gas forcing, and so much momentum inherent in the socioeconomic system that is responsible for steadily increasing greenhouse gas emissions, that there is no room for the luxury of another decade of the scientific studies to finely tune response measures”

    WYNDAM, CITIZEN
    “This issue (global warming) has been studied to death. It is time to act. Stop stalling and start listening to scientific reports already compiled.”

    OFFICE OF ATTORNEY GENERALS FOR MASSACHUSETTS, CONNECTICUT, MAINE, AND
    NEW YORK “The Strategic Plan Emphasizes Research Efforts Geared Toward Adaptation Policies and Fails to Address Adequately the Immediate Need for Mitigation Policies, which Should Be Implemented Simultaneously with the Strategic Plan.” … “After decades of research and debate, there is now a clear consensus among scientists, which has been accepted by the United States, that climate change is occurring and that the combustion of fossil fuels by humans is the primary contributor. See e.g., U.S. Climate Action Report 2002, U.S. Dept. of State, Washington, D.C., May 2002 (“Climate Action Report”) at 5.” … “Most scientists also agree, as discussed in detail by the United States in the Climate Action Report, that global climate change will cause devastating, disruptive, and wide-ranging impacts to climate, ecosystems, and public health and welfare. Climate Action Report at 81, et seq., (Chapter 6). See also, Climate Change Science: An Analysis of Some Key Questions, National Research
    Council (“NRC”), National Academy of Sciences (2001) (“NRC”2001″) at 18-21 (Chapter 6).” … “Regardless of what the specific, regional changes will be, and despite some potentially beneficial localized changes, it is beyond dispute that harmful environmental and climate changes will occur. Among the types of likely changes that the United States has projected are the loss of sensitive ecosystems such as barrier islands, altered agricultural patterns, increased droughts and flooding, and increased infectious and heat-related diseases and illnesses.”

    CRISTINE CORWIN, BLUEWATER NETWORK
    “Time is of the essence and it would be irresponsible to substitute
    unnecessary research for implementation of commonsense solutions. If we
    begin reducing our greenhouse gas emissions now, it will take a lot less time to stabilize the climate.” http://www.bluewaternetwork.org/

    RAYMOND PIERREHUMBERT, THE UNIVERSITY OF CHICAGO
    [Statement from the CCSP: "radiative balance and cloud structure from increased upper tropospheric water vapor is potentially quite large and could be positive or negative." ] … “This statement is incorrect. The feedback from increased tropospheric water vapor is invariably positive.”

    DAVID L. WAGGER, PH.D., SELF
    “This is a misleading statement at best, especially if the intent is to
    divert attention from CO2 as the main driver of anthropogenic climate
    change. Unlike CO2, water has a short atmospheric lifetime, can coexist
    in three phases, and has a highly variable atmospheric distribution.
    While water vapor provides baseline greenhouse heating, CO2 and other
    GHGs supply the perturbation driving climate change.”

    MICHAEL MACCRAKEN, LLNL (RETIRED)
    “There is really very little basis for thinking that the upper troposphere water feedback process could be negative, despite what Lindzen suggests. Were it negative, it would be very hard to have had an ice age (as it would have induced a warming influence to prevent it), we never could have had an ice ball Earth (as there would be to much water aloft), we could never have had Cretaceous warmth as the cooling effect would have countered that, plus the amount of water vapor in the upper troposphere increase from pole to equator (so from cold to warm conditions). The IPCC has reviewed studies of this and there is just very little reason to indicate it is possible, and it may well create important inconsistencies with past climates.

    DAVID L. WAGGER, PH.D., SELF
    Phrasing this as if there is an equal chance or positive versus negative is irresponsible. I think that there is a high level of certainty that: “While water vapor provides baseline greenhouse heating, CO2 and other GHGs supply the perturbation driving climate change.”

    PATRICK NEUMAN
    “All dewpoint and relative humidity data from historical records should be made available in digital format for modeling and analysis.” … ” Please, add: Temperature data by itself is inadequate in monitoring changes in climate. Changes in enthalpy (temperature, humidity, phase change – latent heat exchanges) are very important. It can be misleading to look only at temperature measurements without considering changes in humidity (dewpoints). Near surface humidity is very important in determining the rate of snowmelt, and ice thaw due to the latent heat exchange from the condensation of water vapor on cold surfaces.

    “Increasingly warm conditions at the start of the Eocene caused the extinction of some prominent species of the prior epoch.” .. ” The forests that had housed numerous primate relatives were replaced with denser, often tropical, forests. Species either adapted to the new climate and environments or died out”. http://www.mnh.si.edu/anthro/humanorigins/faq/gt/cenozoic/paleocene.htm

    CALIFORNIA AIR RESOURCES BOARD
    “Land cover change is not only a product of direct human disturbance and modification, but may arise as a consequence of climate change. The
    effects of changing seasonality of precipitation, temperature regimes, or disruption of hydrologic processes (e.g. the loss of perched soil water when permafrost melts) may have important effects on carbon uptake, biogenic emissions, dust, or other direct effects on the atmosphere in addition to potential changes in surface albedo.”

    CALIFORNIA RESOURCES AGENCY
    “While it is important to understand the past, it is not always a good
    guide to the future. Increased globalization is likely to drive land use change in ways not easily predictable from past history. One could infer from language in several places in this chapter that globalization is a key driver but it deserves more explicit recognition.”

    MCCLAIN, NASA
    “Descriptions of the atmospheric and terrestrial knowledge, needs,
    products, and payoffs are more detailed than for the oceans. However, it is thought that the oceans regulate about half of the CO2 uptake and
    global primary production (some recent publications have reduced the
    sequestration numbers). Therefore, the oceans role should be represented in a more balanced manner.”

    JEFFREY GAFFNEY, ARGONNE NAT’L LABORATORY
    “the carbon cycle includes the emissions of isoprene and monoterpene
    hydrocarbons as well as a number of other trace gas species…” These
    emissions are quite large and are now known to play a role in determining the atmospheric composition of the troposphere on regional and global scales. Indeed their presence in areas where there are anthropogenic emissions of air pollutants such as nitrogen oxides and sulfur dioxide, can lead to increased levels or regional ozone and fine aerosols that are important in radiative balance considerations”
    >snip< Ozone is a potent plant phytotoxin. Increased tropospheric ozone (a greenhouse gas) levels will lead to the stomatal resistance being increased leading to reduced uptake of carbon dioxide, less water emitted through evapotranspiration, and less emission of volatile organic carbon (i.e. isoprene) from plants. Carbon sequestration under ozone exposures have been shown to reduce carbon uptake in FACE experiments even at moderate levels …”. “At 60 ppb levels carbon dioxide uptake even under high carbon dioxide exposure was reduced significantly due to this interaction. This type of feedback is not really addressed in this document.”

    NED FORD, SIERRA CLUB
    “A reasonable estimate of the rate of ocean saturation suggests that by
    the end of this century under BAU, we will have effectively saturated the ocean. Further air/ocean transfer will occur, but it will require
    proportionally larger increases in atmospheric levels and much more
    time.”

    NOAA/CMDL
    “What’s missing is that climate change itself could significantly affect our predictions for the carbon cycle even if we understand carbon dynamics pretty well. CH4 is specifically mentioned here and Human Dimensions pops up.”

    End of excerpts from public comments to a draft U.S. Strategic Plan CCSP 18 Jan 2003

    Comment by Pat Neuman — 31 Jan 2006 @ 10:35 AM

  163. Re #s 153, 155, 158:

    Many feel the need to debate the issue, as prescriptions for change affect their bottom line and delaying the change delays the costs associated with change and effects. I agree with Ferdi to a certain degree, but societies take a long time to turn, and the infrastructure we lay down now may affect our future actions and make it more difficult to adapt to a changed system. Therefore, the sooner we begin to plan, the lower the likelihood that our actions today will negatively affect our choices in the future.

    As it is nearly impossible to forecast what will happen in the future (why it is better to plan with scenarios – ask the military or corporations), it is best to have a range of options available to us. The longer we fail to act, the more it is likely that our range of options will be limited.

    Best,

    D

    Comment by Dano — 31 Jan 2006 @ 1:22 PM

  164. Re #157 and “I must have an exceptional group of friends, family and acquaintances because not one has a considered opinion that AGW is proven to be the main reason for the current warming. The few that believe it is quite openly say that it must be so if the “experts” say so.”

    Of the sample of your immediate circle, how many are professional climatologists or planetary astronomers? If the answer is “none,” why should I care what they think on this issue? Undemocratic as it may sound, every individual’s opinion does not have the same value on a scientific issue.

    Comment by Barton Paul Levenson — 31 Jan 2006 @ 1:33 PM

  165. Re #164 Outch!

    Since we are constantly told all “the experts” agree why is nothing happening? Why are we still jetting off to the sun and doing all the other carbon intensive things?

    I am glad that in this country at least every citizen’s view counts equally when sitting on a jury or casting a vote regardless of whether the issue is scientific or not. Science is peppered with both with amateur breakthroughs and expert frauds and goofs.

    But to answer the question a few.

    Comment by David H — 31 Jan 2006 @ 7:32 PM

  166. Re #151

    There may be changes in cloud cover during solar cycles that cause a variation in cloud effect of +/- 2W/m2 during a cycle but this doesn’t mean there will be similar changes over the long term between the same part of different cycles. What you need are cloud records from several cycles to determine how much cycle-independent cloud feedback there is.

    Comment by Chris O'Neill — 1 Feb 2006 @ 7:48 AM

  167. Re #166:

    Chris, you are right, one need several solar cycles, if possible of different amplitude, to see if the cloud changes follow the solar changes on longer term. Unfortunately, we have only (relative) accurate data for the last two cycles, thanks to satellites.

    There still is discussion about the difference in TSI (total solar irradiation, see Fig. 1 in Scafetti and West) between those cycles. But if we assume that there is a slight increase, this should be visible in the cloud data as a decrease in cloud cover.

    Indeed, if you have a look at Fig.1 of Kristjansson ea., there is a decrease of ~0.5% in low cloud cover from peak to peak and a decrease of ~1% in low cloud cover for the throughs. But the latter may have been influenced by the 1998 El Nino. And the change also can be a response to the general increase in ocean temperatures and/or longer term internal ocean cycles… As we are near a solar minimum, it may be interesting to compare the extended TSI and low cloud data up to now.

    Comment by Ferdinand Engelbeen — 1 Feb 2006 @ 12:09 PM

  168. Re #162 Sorry Pat, I don’t have any answer for the questions you ask me about. But I’m under the impression that you may know what those answers are. If they help understand why the tropospheric temperatures (and to a lesser degree the surface ones) are not behaving as predicted, according to the source I gave, please let me know. In any case, people seem to have migrated to other topics, which unfortunately I don’t have the time to follow now. Perhaps they consider “the science to be settled” on this one.

    Comment by Mikel Marinelarena — 1 Feb 2006 @ 6:40 PM

  169. re 168. Mikel,

    Maybe I think I know the answer to some of them.

    I’ve been making new photo plots on line showing that January 2006 was the warmest January of record (1890s-2006) for climate stations in eight or more states in the Midwest and Great Plains.

    Comment by Pat Neuman — 2 Feb 2006 @ 12:01 AM

  170. Re #160: Mikel, you need to read at least the entire executive summary. But, to briefly answer your question:

    “In 2000 and 2001, the NRC and the IPCC both concluded that global-mean surface temperature increases were larger and differed significantly from temperature increases in the troposphere. The new and improved observed data sets and new model simulations that have been developed require modifications of these conclusions.”

    “Either amplification effects on short and long time scales are controlled by different physical mechanisms, and models fail to capture such behavior; and/or remaining errors in some of the observed tropospheric data sets adversely affect their long-term temperature trends. The second explanation is judged more likely.”

    In other words, the past data that disagreed with the models has been found to be incorrect. The arguably over-subtle wording is because the proprietors of the past erroneous data sets are co-authors of the report and so are eating some pretty major crow just now. Elsewhere in the report there is detailed discussion of exactly why it has been difficult to obtain consistent data from both satellites and radiosondes.

    For a nice narrative (with citations) on the history of global warming skeptic/denialist/contrarian scientists (and a few non-scientists), see http://stephenschneider.stanford.edu/Climate/Climate_Science/CliSciFrameset.html .

    Comment by Steve Bloom — 2 Feb 2006 @ 10:27 PM

  171. Thanks Steve. I’ll try to read that article this weekend. But Stephen Schneider is one of the scientists that in 1976 was endorsing the global cooling scare, did you know that? Even William Connolley disaproved his quote in Lowell Ponte’s alarmist book ‘The Cooling’.

    Still, the question remains: why, according to the very recent (11/05) US Climate Change Science Program draft, is the lower troposphere warming slower than the surface in almost all measurements? There must be some way of wording a simple explanation for this evident contradiction to the AGW theory.

    Comment by Mikel Marinelarena — 3 Feb 2006 @ 8:08 PM

  172. This machine translated spam is hysterically funny, but I hope the linkspammer’s gone.

    Comment by Hank Roberts — 4 Feb 2006 @ 4:57 PM

  173. Like the comment above I also am extremely sceptical of the type of computer models being used for climate simulation. And yes models (visual, hydro and electronic) are my area of expertise!

    For the types of models used (deterministic PDEs/ODEs/Parameterised/empiricals) it is a simple fact that perturbation of the initial and/or boundary conditions can drastically alter the outcome as can a multitude of other “element” assumptions i.e. amount of cloud cover, ground characteristics, ocean and wind currents, convection etc let alone such arcane things as inability to model “artefacts” like water dimers, weak bands, elevated state IR absorption etc etc etc. The list of assumptions and guesses that forms a foundation of the models is almost endless and yet it is known that only a small change can have a completely misleading convergence effect. Even stochastic approaches cannot resolve the unresolvable: subgrid-scale phenomena, and large-scale (chaotic) non-determinism both of which can, by themselves, drastically change outcomes.

    The parallel with other models may be relevant. When electrical models first started the numerical approach was fine for frequencies up until about 100kHz. As our understanding of the physics improved so did the “approximations” of real elements (aka models) and the useful frequencies now extend into the GHz area. However we know several things:

    1: that after certain frequencies the “theory” diverges wildly from reality
    2: even within the known limits and with very well defined models we routinely get “bitten” by all sorts of small anomalies
    3: these “small” anomalies have wildly convergent or divergent effects on predictions

    Unfortunately we cannot do experiments with the climate and we only have one set of data and starting conditions to align to. The early climate models needed all sorts of “fudges” to push them to correlate with observed data and not to go into runaway. In other words the models have been refined with many “uncertain” effects to force them into alignment with the last 100 years (which are, as the IPCC report stated: “… of the same magnitude as natural climate variability”).

    In particular the failure of current mainstream models (e.g. GISS) to align with some near and far historical data is not explained e.g.

    1: Violent but short lived changes of up to 15C in a few decades!
    2: Recent history, 1400/1700 – the 1940-70 cooling and even the current winter in northern hemisphere
    3: Not so recent history when CO2 was 5-10 times higher than present (1000-1500ppm)
    4: During some cooling periods CO2 actually rose (eg Miocene period).
    5: Misalignment of “uncertain” effects and observed climate (e.g. southern versus northern aerosols) etc
    6: Misalignment of surface, tropo and other recent temps including lower than predicted increases.

    However, it is the “doomsday” predictions of these models which are now being used!

    I note in passing that other types of models provide a quite different outcome; which model is the best and which outcome is correct?

    Even the subject of measuring temperatures and the “fudging” required to correct for urban effects; cities (i.e. proliferation of traffic and air conditioners), “heat islands”, biases in surface versus sea temperatures and northern (versus southern) are just a few items of concern. Even as late as last year satellite data (which I had considered to be most reliable) was found to be flawed. Contrary to the statements by Gavin et al above not all of the concerns have been addressed by any means! For instance we know that many isolated temperature curves (surface and sonde) do not follow the overall trend. How can this be?

    Penultimately some scientists have forgone the “truth” principle to ride the climate juggernaut for more research funds. According to one American climatologist, the “scare-them-to-death” approach seems to be the best way to get money for climate studies. Dr. Stephen Schneider, a leading prophet of manmade climate warming (and previously cooling!), stated this bluntly:

    “To capture the public imagination… we have to… make simplified dramatic statements, and little mention of any doubts one might have…. Each of us has to decide the right balance between being effective and being honest”.

    Add to this mix extremist politicians who have found GHGs so convenient for their anti-technology, anti-corporate anti-everything agenda.

    Is there any wonder that some, including many scientists, are sceptical of the “predictions”.

    To discard these criticisms arbitrarily or to treat intelligent scepticism with ridicule will only detract from any case made.

    Having said that I would like to pose some questions and comments to those who know more than I do about this issue.

    1: The statements about CO2 and its link to global temperatures have some serious problems.

    Although it seems clear to me that, barring some hidden source of CO2 (i.e. the Siberian peat bogs or the recent discovery that plants produce large amounts of methane!), the increase in atmospheric CO2 is probably mainly due to anthropogenic sources.

    However, if CO2 is so intrinsically linked to temperature how is it possible that, with no other observable geological events (meteor, volcano, tilt etc) CO2 can increase during a cooling period as has been observed in the geological record?

    It is not possible for the relationship between CO2 and temperature to be as fixed as the models assume: either the geological record is incorrect or the models are wrong!

    2: Different models produce different results! The outcome from solving all the ODEs/PDEs etc. varies with the methods used. Some of the models predict cooling events, why are the only models propagated those which predict “boil in oil” scenarios?

    3: For the last 10,000 years the climate has been relatively “quiet” but previous to this climate change has been generally violent and abrupt. Changes of +/- 5C per decade have been commonly recorded throughout the geological record. These changes were not isolated in small areas but were global in nature. Again there are no geological reasons for these abrupt variations. What caused them? Unless the models align with these known events then any future predictions based on the models are as equally invalid as their ability to correlate with the past!

    4: Even in our recent past events like the Little Ice Age, multiple glacial advances and retreats have no apparent causes and were not accompanied by commensurate CO2 changes? There appears to be no rational explanation for these relatively violent events and they do not appear to be forced by CO2 changes as the models predict?

    5: The table used to indicate the relative contribution of GHGs in Real Climate is useless.

    To anyone involved in computer modelling and numerical analysis the statements:

    “This isn’t a perfect calculation but it’s quick and easy and is close enough to the right answer for our purposes”

    and

    “but that is complicated for clouds, O3 and Aerosols which have impacts on solar radiation as well as the long wave, so I only give that value for the ‘pure’ greenhouse gases”

    are extraordinarily worrying!

    Further the relationship between absorption curves is very complicated. This is different for each molecule and each environment. The table would have been more useful if the “change” corresponded in magnitude to the observed changes in the atmosphere rather than complete removal and was backed by empirical evidence.

    These simplistic models for the absorption of just one of the molecules alone (water vapour) are, with all due respect, rubbish! See for example http://physicsweb.org/articles/world/16/5/7/1

    As a last indicator we know of geological times when the CO2 was up to 10 times its current level and the temperature was only a few C above what it is now. Plug that into GISS and all biological life would have been extinquished! Again either the model is wrong or the geological record is wrong!

    Accordingly as an indication of “contribution” at atmospheric levels of absorption the table is effectively useless and should not be used for any indication of the whole or part of the contribution of ANY of the GHGs other than to order of magnitude levels. Please stop using it!

    6: The estimate of the warming effect for a doubling of CO2 (3 +/-1C) is also not supported by the geological record. CO2 levels have correlated with temperature only ~50% of the time of large climate changes and in many cases followed not led temperature changes. However there are numerous places in the record where CO2 fell during warming periods or rose during cooling (e.g. Miocene). Again this implied fixed relationship is not supported by the geological record.

    7: The “human” induced changes in methane are now in serious question after the recent German research about plants and methane! So the statement “something like double that” regarding the effect of the other GHGs becomes unsubstantiated!

    And before the personal stuff starts:

    1: Yes it seems the planet is getting warmer, about 0.5 – 0.7C in the last 150 years. However this is well with normal limits and is actually quite a mild change by geological standards

    2: Yes CO2 is a greenhouse gas and we have increased its concentration in the atmosphere.

    3: Yes some part of the warming is probably due to anthropogenic causes.

    4: Could the computer models be correct? Yes with about the same probability they could be wrong!

    The models are far too simplistic to even come close to modelling the climate, not in the least because they do not even give a reasonable approximation of modelling the “effective” absorption profiles of the three most prominent GHGs in the atmosphere: Clouds, H2O and CO2 let alone all the complexities of the other elements involved.

    5: Yes I do believe that we should be using less fossil fuels For all sorts of reasons not least is that they are a precious and irreplaceable resource.

    6: At the current rate of warming the countries worst affected by sea level thermal expansion (Asia) will be flooded by the tectonic plate subsidence and tsunamis long before that caused by warming! This is an example of the alarmist scaremongering crap that pervades this debate in the popular media.

    Prof Jon Jenkins

    [Response: Well, Professor Jenkins, where to start? You have listed a litany of problems, none of which have specific enough criticisms to properly rebut or discuss, but which show much evidence of having been picked up second or third hand. Much of your critique has no obvious basis - rapid global temperature changes of +/- 5C? the expectation that climate models should be able to produce seasonal weather forecasts? Standard out of context mis-quotes of Stephen Schnneider? - that I am not inclined to pursue this discussion. However, you specifically criticise my post on water vapour, and declare it 'extraordiniarily worrying' - Quite frankly, I'm flummoxed. Back of the envelope approximations are used throughout physics to illustrate various points and orders of magnitude of different effects and this is exactly the tack taken here. If you would care to point out a more careful analysis, I would cheerfully acknowledge it. But, your implicit claim that I must be fundamentally wrong simply because you don't understand the concept the radiative forcing seems a little presumptious. I therefore invite you to focus on your criticism point 5, and explain to me (with references please) why you are so worried. A little work with a line-by-line radiative transfer code, integrated over the planet and over the seasonal cycle should provide you with a more correct answer, and if my numbers were out by more than a few percent, I will post your analysis here and link to it from my own. Of course, you may prefer to randomly fling criticisms around as above and never choose to make a substantive point. I await your response. - gavin]

    Comment by Jon Jenkins — 4 Feb 2006 @ 5:15 PM

  174. Prof. Jenkins, the page you point us to says they too are relying on “crude calculations” — did you look for followup info from the actual researchers being described as saying this, to see if they supported their back-of-envelope calculation later?

    Quoting from the article:

    “… Water vapour in the atmosphere can change phase, which leads to more clouds, and greater cloud cover means that more sunlight is reflected straight out of the atmosphere. Crude calculations suggest that the two effects approximately balance each other, and that water vapour does not have a strong feedback mechanism in the Earth’s climate.

    We have tried to outline some of the unresolved issues concerning water in the atmosphere. …”

    That was May 2003. PhysicsWeb isn’t sensationalist but this was journalism; did they get anywhere with the refereed journals, substantiating this?

    Comment by Hank Roberts — 4 Feb 2006 @ 10:19 PM

  175. Jon Jenkins #173

    You’ve really opted for quantity over quality here, I must say. It makes it hard to know where to begin and how to approach your post. So I am just going to pick and choose a few things, perhaps you will surprise me and provide something concrete to focus on.

    Regarding “the failure of current mainstream models”

    1: Violent but short lived changes of up to 15C in a few decades!

    I’m sorry, but you really need to provide some references for this. What are you talking about?

    2: Recent history, 1400/1700 – the 1940-70 cooling and even the current winter in northern hemisphere

    - I havn’t seen model runs over 1400/1700, where can I see that?
    - The mid century cooling is well reproduced, see here:
    http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm
    - The current NH winter is weather, don’t look to a climate model for weather forecasts.

    You presented some “questions”:

    1: The statements about CO2 and its link to global temperatures have some serious problems.

    What statements have what problems?

    Although it seems clear to me that, barring some hidden source of CO2 (i.e. the Siberian peat bogs or the recent discovery that plants produce large amounts of methane!), the increase in atmospheric CO2 is probably mainly due to anthropogenic sources.

    The CO2 can be conclusively attributed to fossil fuel burning due to the isotope signatures of the C and O atoms. That recent study you mentioned does not say that plants only started producing methane in the last 150 years or so. We are observing a change in atmospheric composition, the explanation must be something that has changed. The Siberian peat bogs melting is a result of anthropogenic warming, ie our CO2 came first, if the bogs starts to produce their own CO2, that is called a feedback mechanism.

    It is not possible for the relationship between CO2 and temperature to be as fixed as the models assume: either the geological record is incorrect or the models are wrong!

    The correlation of CO2 levels and temperature is not an assumption of the models, it is an output! It is also an observation, both over the last century and over the last almost 1 million years in the glacial records.
    http://www.grida.no/climate/ipcc_tar/wg1/fig2-22.htm
    Other geological periods had other major differences and offer considerably less data. It would be nice to have perfect understanding of every point in geological time but, a) it is unlikely we ever will and b) let’s start with today where we can measure most of what we can think of.

    2 … Some of the models predict cooling events, why are the only models propagated those which predict “boil in oil” scenarios?

    References please? What models predict cooling?

    3 … Changes of +/- 5C per decade have been commonly recorded throughout the geological record. These changes were not isolated in small areas but were global in nature.

    References please? I hope you are not so uninformed that you are talking about the glacial interglacial cycles, those swings took thousands to tens of thousands of years. Probably not, so what are you talking about?

    4: Even in our recent past events like the Little Ice Age, multiple glacial advances and retreats have no apparent causes and were not accompanied by commensurate CO2 changes? There appears to be no rational explanation for these relatively violent events and they do not appear to be forced by CO2 changes as the models predict?

    Isn’t it a little alarmist to characterize the ~.5oC over ~300 years that was the LIA as a violent event (and it was not even globally synchronized)? Really, who are you kidding? And please provide some references for some “violent” glacial retreats and advances in the last few hundred years, or whenever you wish.

    7: The “human” induced changes in methane are now in serious question after the recent German research about plants and methane!

    Sorry, it is not human emissions that are now in serious question, it is the natural methane budget that needs to be re-examined. I think you are confusing “just discovered” with “just began” or something. Whatever it is that the plants are doing that we only just noticed, I think the default assumption must be that they have done it all along despite us not being aware.

    I do hope you will offer up some support for at least a few of the bullets in your machine-gun of a posting, it is not fair to ask people to argue against or explain away something you have not clearly described.

    Comment by Coby — 5 Feb 2006 @ 1:48 AM

  176. It is interesting how quickly these responses get personal so quickly and
    even more interesting the failure to acknowledge valid criticisms. It is often a sign of belief versus fact in a debate!

    I am not going to write a thesis on this issue nor will I quote tomes on
    geology but I will respond to several issues raised

    Gavin’s comments

    Much of your critique has no obvious basis – rapid global temperature
    changes of +/- 5C?

    Read the full GRIP report. I quote a relevant phrases here:

    “The 018 and H2 records confirm that large and rapid temperature oscillations have occurred through most of the last 110,000 year period. They are of a scale that has not been experienced during the past 10,000 years in which human society mainly developed.

    ….Especially astonishing are the very short times needed for major warmings. A temperature increase of 5°C can occur in a few decades.

    ….The fast climatic variations observed in the 018 record of Greenland ice cores would attract only limited attention if they were only local in character. However, there is ample evidence that these fast climatic fluctuations are also affecting regions far away from Greenland. Indeed, there is good correlation between some of the fast climatic variations observed in the Greenland ice cores and variations observed in deep sea sediment cores from the North Atlantic.” (11)

    It is well known that during exit from the last Ice Age for example that sea levels and temperature rose at about 10 times their current rate. This was NOT preceded by CO2 rises I might add and evidence can be found in any standard geological text.

    These and a myriad of geological facts are present in the literature. However many in the current debate seem to choose to conveniently ignore the geological history of earth. I make the simple statement again: either the climate models are wrong or the geological history is wrong!

    the expectation that climate models should be able to produce seasonal weather forecasts?

    The discussion of climate versus weather is superfluous. The fact is that, barring a perturbating geological event (i.e. in steady state) the models do not and cannot predict a cooling on any large scale: they predict inexorable warming! IF the “weather” in the Northern Hemisphere becomes climate or if we show any cooling trend then the models are wrong! Fudging with aerosols to “cool” the models predictions in the Northern Hemisphere should have also predicted faster rises in the southern hemisphere (less soot etc). Oopps, wrong again, lets go looking for another fudge!

    Standard out of context mis-quotes of Stephen Schnneider?

    This was not quoted out of context at all. It clearly indicates a willingness
    to “embellish” the public record. The fact is that some scientists have become
    Pavlov’s Dogs for research funds handed out by politicians (I know because I am
    both!).

    However, you specifically criticise my post on water vapour, and declare
    it ‘extraordiniarily worrying’ – Quite frankly, I’m flummoxed. Back of the
    envelope approximations are used throughout physics to illustrate various
    points and orders of magnitude of different effects

    As long as the results are viewed as “order of magnitude” and not as
    conclusive proof then this may be acceptable, and I stress may. However the
    table was then used to “prove” your hypothesis. I contend that the proof would
    have required more than “order of magnitude” accuracy. Simply correcting for the
    sum errors is wrong, it took no account of either the chemistry or structure of
    the atmosphere and the simple fact is if we redo your analysis with a factor of
    10, as you suggest, your theory falls over. Unfortunately there is no “more
    careful analysis” as you suggest which is exactly my point.

    The point was exactly as you put it: “back of the envelope” calculations are
    NOT science. It is only in the recent past that this has become accepted as
    science. To use what is effectively guesswork based on mathematic models we know
    are defective, using deterministic solutions we know are “fragile” (particularly
    in ill-defined systems) and based on theory we know is either incomplete or only
    approximate to affect billions of people and funnel trillions of dollars is
    ludicrous! The very fact that there is no evidence either way does not make a
    theory correct by default!

    [Response: Well, I thought this is what you were referring to. However, you make a serious error in extrapolating a temperature change in Greenland to a 'global' change. The changes in Greenland are most probably related to changes in the North Atlantic circulation and are comparable to the changes seen in 'shutdown' experiments done with all of the different models (see Stouffer et al, 2005; Vellinga and Wood, 2001; Rind et al 2001). There are correlations of these events around the region, and as far away as East Asia (Yang et al, 2004) and Santa Barbara Basin in the Pacific (Kennett et al), however the temperature changes are much smaller the further away you get from Greenland. A '5 C' global change is completely unsupportable. Remember that the full glacial to interglacial change (which took around 10,000 years) was only around 5 or 6 deg C. Next point. CO2 in glacial-to-interglacial change is of course a feedback to the changes in orbital forcing and is known to lag the temperature - however the GHG forcing (CO2, methane and N2O) ends up providing almost half the forcing of the total change. So a feedback, but an important one. (see our previous post on this).
    Contrary to your next assertion, the difference between weather and climate is fundamental, not superfluous. I presume that you are familiar with the concept of initial value problems (weather) with boundary value problems (climate), and in chaotic systems the difference between an individual path (weather) and the manifold on which all paths lie (climate). Models do not produce 'inexorable' warming - they produce cooling as a function of volcanic eruptions (as observed), changes in orbital forcing (as observed), from 1940-1970 (as observed), at the LGM (as observed). With no changes in forcings, they show interannual variability of a similar magnitude as seen in the data, both warming and cooling.
    If you are not able to find the full Schneider quote, I suggest you simply look at a previous rebuttal and the full quotation here.
    And finally, your criticism of my estimates of the long wave absorbtion in the atmosphere (which I claim are good to a few percent, not an order of magnitude) appears to based on nothing at all. If you cannot point to a better estimate that is substantially different, while my analysis is a very good match to a completely indpendent study done almost 20 years ago (Ramanathan and Coakley, 1978), it seems odd that you have concluded it must be wrong.
    As you might suggest to one of your own students who brings in a piece of work that relies too heavily on secondary sources, I suggest you avail yourself of your no-doubt well equipped university library to actually read some primary sources prior to your next reply. The IPCC TAR report has almost all the references you will need. I will leave it to the other commenters to deal with your other mis-conceptions. By the way, if you are actually interested in a serious discussion, I suggest that you focus your efforts on one particular topic at a time. -gavin]

    Hanks Comments

    Hank I could not have put it better myself:

    Prof. Jenkins, the page you point us to says they too are relying on
    “crude calculations” — did you look for followup info from the actual
    researchers being described as saying this, to see if they supported their
    back-of-envelope calculation later?

    I state again:

    Back of the envelope “crude calculations” are NOT science. It is only in the
    recent past that this has become accepted as science. To use what is effectively
    guesswork based on mathematic models we know are defective, using deterministic
    solutions we know are “fragile” (particularly in ill-defined systems) and based
    on theory we know is either incomplete or only approximate to affect billions of
    people and funnel trillions of dollars is ludicrous!

    Do I have a better theory? No. But does that mean I accept what I can clearly
    see to be defective models as being the final solution which should drive the
    policy of the western world? Absolutely NOT!

    The point is exactly as it is to Gavin: we should not be basing global energy
    policy and spending on little better than guesswork! What we need is hard
    SCIENCE of which there is little and the press, politicians and eco warrior
    scientists are much to blame.

    Coby’s Comments

    You’ve really opted for quantity over quality here, I must say. It makes
    it hard to know where to begin and how to approach your post. So I am just
    going to pick and choose a few things, perhaps you will surprise me and
    provide something concrete to focus on.
    Regarding “the failure of current mainstream models”
    1: Violent but short lived changes of up to 15C in a few decades!
    I’m sorry, but you really need to provide some references for this. What are
    you talking about?

    See the GRIP report mentioned above, actually it was part typo but the cores
    both in Greenland and Atlantic clearly showed 5C/decade magnitude. Many basic
    geological texts also relate temperature and sea changes up to 10 times the
    current rates across the globe. Goodness it is even in the IPCC report:

    On the other hand, very rapid warming at the start of the Bolling-Allerod period (14.5 to 13ky BP), or at the end of the Younger Dryas (12.7 to 11.5ky BP) may have occurred at rates as large as 10°C/50 years for a significant part of the Northern Hemisphere“.

    The warming phase, that took place about 11,500 years ago, at the end of the Younger Dryas was also very abrupt and central Greenland temperatures increased by 7°C or more in a few decades“.

    2: Recent history, 1400/1700 – the 1940-70 cooling and even the current
    winter in northern hemisphere
    - I havn’t seen model runs over 1400/1700, where can I see that?

    I am not sure where this was but a both a Canadian and British university ran
    simulations of the mid millennia period using estimations of solar irradiance and
    gases from fossils and trees. It was published on web sites and I will have dig
    it up. I do not keep all this stuff at fingertip but the correlation was not
    good with CO2 and much better for solar irradiance. This was a few years ago and
    I have not seen any more simulations since. Not unexpected in the current
    climate (to use a pun) that groups publish “unpopular” results. This has been
    the other downside to the current debate: any scientist that publishes
    controversial findings is castigated not only by some of his “eco warrior” peers
    but especially by the “anti-everything” political agenda and popular press. I
    know colleagues who work for CSIRO Climate in Australia who are literally
    fearful of uttering anything which contradicts the “corporate spin” designed to
    win research funds, in fact they are officially gagged from speaking.

    - The mid century cooling is well reproduced, see here:

    http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm

    The models I have seen vary considerably on their correlation for the 1940-70
    period. The IPCC picked the best model however I might add this process of
    “tweak” the model till we get correlation and then accept that the model is
    correct is not science and flies in the face of all we know about these types of
    models. Again I quote from the IPCC report itself:

    Different
    models may give quite different patterns of response for the same forcing,
    but an individual model may give a surprisingly similar response for
    different forcings.”
    And again in Section 7.3, “….considerable
    uncertainties still exist concerning the extent to which present climate
    models correctly describe the oceanic response to changes in the forcing.

    The model should basically be in correlation for all spatial and temporal
    regions. If it is not then the model is wrong and its predictions are wrong. The
    question – can the successful simulation shown in the figure be used to support
    the proposition that changes in CO2 levels (presumed to be due to
    fossil fuel burning) are causing the observed temperature rises over the past
    century? To which there is only one answer: ONLY if no other model
    assumptions can replicate the observed behaviour, and also if the model can be
    applied successfully to data from the more distant past, when much greater
    ranges in temperature change have been inferred.

    - The current NH winter is weather, don’t look to a climate model for
    weather forecasts.

    As I said above: barring some “event” the models will not accommodate a “cold
    winter” and there has been no event! The arbitrary nature of when weather
    becomes climate makes the decision difficult but it is irrelevant: according to
    the models we can’t get cooler in steady state!

    You presented some “questions”:
    1: The statements about CO2 and its link to global temperatures have some
    serious problems.
    What statements have what problems?

    The assumption that CO2 drives temperature. Even the IPCC report touched on
    the phase relationship raised by Fischer but then simply refused to consider any
    of the latter work by others. The evidence points more and more to a lag
    relationship not a leading one!

    Although it seems clear to me that, barring some hidden source of CO2
    (i.e. the Siberian peat bogs or the recent discovery that plants produce
    large amounts of methane!), the increase in atmospheric CO2 is probably
    mainly due to anthropogenic sources.
    The CO2 can be conclusively attributed to fossil fuel burning due to the
    isotope signatures of the C and O atoms. That recent study you mentioned
    does not say that plants only started producing methane in the last 150
    years or so. We are observing a change in atmospheric composition, the
    explanation must be something that has changed. The Siberian peat bogs
    melting is a result of anthropogenic warming, ie our CO2 came first, if the
    bogs starts to produce their own CO2, that is called a feedback mechanism.

    The isotope data indicate that contributions to the atmosphere come from
    “old” sources but I do not just blindly follow the “plants preference for
    C12/C13″ and has been constant throughout time. As I said below in the
    original post it seems probable on both logical and available science that this
    is so. Unlike many I do not just accept “popular” or “consensus” as being
    science fact.

    It is not possible for the relationship between CO2 and temperature to be
    as fixed as the models assume: either the geological record is incorrect or
    the models are wrong!
    The correlation of CO2 levels and temperature is not an assumption of the
    models, it is an output! It is also an observation, both over the last
    century and over the last almost 1 million years in the glacial records.

    http://www.grida.no/climate/ipcc_tar/wg1/fig2-22.htm

    No, this is factually incorrect! The relationship is not fixed at all. The
    relationship should hold for ALL periods and this is not the case and very clear
    examples exist both in the recent and far past where the relationship is not
    explained by the theory.

    Other geological periods had other major differences and offer
    considerably less data. It would be nice to have perfect understanding of
    every point in geological time but, a) it is unlikely we ever will and b)
    let’s start with today where we can measure most of what we can think of.

    Exactly and no! If the models do not correlate with what we know then the
    models are wrong!

    2 … Some of the models predict cooling events, why are the only models
    propagated those which predict “boil in oil” scenarios?
    References please? What models predict cooling?

    I will have to dig these up but both deterministic and other theory (chaos)
    etc predict cooling during the first half of C21. The IPPC references some
    of these but will have to get back!

    3 …Changes of +/- 5C per decade have been commonly recorded throughout
    the geological record. These changes were not isolated in small areas but
    were global in nature.
    References please? I hope you are not so uninformed that you are talking
    about the glacial interglacial cycles, those swings took thousands to tens
    of thousands of years. Probably not, so what are you talking about?

    See above, these are overtly evident

    4: Even in our recent past events like the Little Ice Age, multiple
    glacial advances and retreats have no apparent causes and were not
    accompanied by commensurate CO2 changes? There appears to be no rational
    explanation for these relatively violent events and they do not appear to be
    forced by CO2 changes as the models predict?
    Isn’t it a little alarmist to characterize the ~.5oC over ~300 years that
    was the LIA as a violent event (and it was not even globally synchronized)?
    Really, who are you kidding? And please provide some references for some
    “violent” glacial retreats and advances in the last few hundred years, or
    whenever you wish.

    Again see above for 5C/decade changes

    7: The “human” induced changes in methane are now in serious question
    after the recent German research about plants and methane!
    Sorry, it is not human emissions that are now in serious question, it is the
    natural methane budget that needs to be re-examined. I think you are
    confusing “just discovered” with “just began” or something. Whatever it is
    that the plants are doing that we only just noticed, I think the default
    assumption must be that they have done it all along despite us not being
    aware.

    The assumption (and there are far too many in this debate already) had been
    that the increase in methane for the last 150 years was totally anthropogenic
    and it is probably wrong!

    Comment by Jon Jenkins — 5 Feb 2006 @ 7:30 PM

  177. Well, I thought this is what you were referring to. However, you make a
    serious error in extrapolating a temperature change in Greenland to a
    ‘global’ change. The changes in Greenland are most probably related to
    changes in the North Atlantic circulation and are comparable to the changes
    seen in ‘shutdown’ experiments done with all of the different models (see
    Stouffer et al, 2005; Vellinga and Wood, 2001; Rind et al 2001).

    The change (not as abrupt) was also recorded in Pacific corals at ~ the same
    time. This was a global change which occurred over a few short years and was
    more intense in Northern latitudes. As far as the geological record shows there
    was no “forcing” event to cause this.

    There are correlations of these events around the region, and as far away
    as East Asia (Yang et al, 2004) and Santa Barbara Basin in the Pacific
    (Kennett et al), however the temperature changes are much smaller the
    further away you get from Greenland. A ’5 C’ global change is completely
    unsupportable. Remember that the full glacial to interglacial change (which
    took around 10,000 years) was only around 5 or 6 deg C.

    Over a decade yes I agree but vast and large sections of the planet did
    undergo such changes. And although the average global change was ~6C there is
    ample evidence that this average was achieved by rapid global oscillations within decade periods. The current warming is entirely consistent with
    that record.

    Next point. CO2 in glacial-to-interglacial change is of course a feedback
    to the changes in orbital forcing and is known to lag the temperature –
    however the GHG forcing (CO2, methane and N2O) ends up providing almost half
    the forcing of the total change. So a feedback, but an important one. (see
    our previous post on this).

    No one of any sense is arguing that CO2 is not a forcing element of
    importance. But the weighting of other forcing is debateable. We know that the
    Solar Irradiance is also the highest it has been for at least 400 years.

    Contrary to your next assertion, the difference between weather and
    climate is fundamental, not superfluous. I presume that you are familiar
    with the concept of initial value problems (weather) with boundary value
    problems (climate), and in chaotic systems the difference between an
    individual path (weather) and the manifold on which all paths lie (climate).

    Intimately, which is why I am sceptical!

    Models do not produce ‘inexorable’ warming – they produce cooling as a
    function of volcanic eruptions (as observed), changes in orbital forcing (as
    observed), from 1940-1970 (as observed), at the LGM (as observed). With no
    changes in forcings, they show interannual variability of a similar
    magnitude as seen in the data, both warming and cooling.

    As I clearly said, “barring a perturbating geological event (i.e. in steady
    state) the models do not and cannot predict a cooling on any large scale: they
    predict inexorable warming”. This still stands. We have had no major eruptions,
    no major TSI events, no major GHG changes => we must see a continuing pattern of
    warming EVEN over yearly scales. IF we don’t the models are wrong!

    If you are not able to find the full Schneider quote, I suggest you
    simply look at a previous rebuttal and the full quotation here.

    Regardless of what Schneider quote I have seen this so many times to know
    that it is now common practice. It is particularly rife in the life sciences
    such as Biology and Ecology where the “noble cause” has become more important
    than truth and consensus has become fact.

    And finally, your criticism of my estimates of the long wave absorbtion
    in the atmosphere (which I claim are good to a few percent, not an order of
    magnitude) appears to based on nothing at all. If you cannot point to a
    better estimate that is substantially different, while my analysis is a very
    good match to a completely indpendent study done almost 20 years ago (Ramanathan
    and Coakley, 1978), it seems odd that you have concluded it must be wrong.

    Firstly you used the term “order of magnitude”. Gavin, you misunderstand my
    criticism! Even a cursory reading of the literature tells a simple story:
    evaluating the absorbtion profiles of even a single species of GHG in a lab is a
    “hard” problem, doing it in the atmosphere with all its added chemical and
    physical issues is even “harder”. Even when using the most sophisticated models
    and the latest profiles (eg HITRAN) there are significant differences between
    theory and reality in clear skies. In cloud the theories and models are
    basically useless! To say otherwise is deceptive. I am sure you know this
    research better than I do. The absorbtion anomaly is still an unresolved issue
    as is cloud behaviour and trace chemistry even more so.

    The result, as far as I am concerned, is that anyone who claims to be able to
    work out the contributions to “few percent” is just having themselves on and I
    think every atmospheric chemist in the world would agree. This may change as we
    better understand the underlying quantum physics involved and can estimate the
    intensities better but for the moment everything I have read tells me that we
    just don’t know enough to make good decisions.

    However, even if we accept the few percent in the climate models it is even
    these “few percent” which determine the difference between the next glaciation
    or molten lead! Again I, and many others, will not support decisions of such
    import when they are based on such evidence

    Comment by Jon Jenkins — 5 Feb 2006 @ 11:01 PM

  178. > Hanks Comments
    > Hank I could not have put it better myself: …

    Uh, really, you should be able to do better yourself, that was my point.
    You could look up the people quoted, using the links in the news item you pointed us to, and see if they ever published that idea in a journal.

    You can do better.

    Comment by Hank Roberts — 6 Feb 2006 @ 12:38 AM

  179. Re Jon Jenkins,

    You claimed:
    “Violent but short lived changes of up to 15C in a few decades”
    and
    “Changes of +/- 5C per decade have been commonly recorded throughout the geological record. These changes were not isolated in small areas but were global in nature”
    and as support you offer a quote about GRIPS “Especially astonishing are the very short times needed for major warmings. A temperature increase of 5oC can occur in a few decades”

    In short you claimed global changes of 5oC and even 15oC and to support it provide evidence of regional changes of 5oC over several decades. 15oC/decade global is not equivalent to ~2oC/decade regional. Now you did back away a little claiming a typo (I assume about 15oC) and acknowledging that the evidence you offered is for Greenland and N Atlantic, but in the very next breath you claim “Many basic geological texts also relate temperature and sea changes up to 10 times the current rates across the globe” and then quote again IPCC references to strictly regional changes. So back to square one, hand waves and unsubstantiated claims.

    “It is well known that during exit from the last Ice Age for example that sea levels and temperature rose at about 10 times their current rate.”

    Sea level, sure, that’s a part of glacial melting, but temperature? Sorry, but no. The temp rises out of the deep glacial periods were about two decimal orders of magnitude slower than the current .2oC/decade. Please see here:
    http://www.brighton73.freeserve.co.uk/gw/paleo/20000yrfig.htm
    It is quite true that we do not have the resolution to conclusively show there were no decadal trends that were short lived but as steep or steeper than the last thirty years, much less global in nature, but neither is there anything in that record to support your contention above. Even if we take you to mean .8oC per century current trend, your claim would be 8oC/century, which puts the whole shebang in about one century when in fact it took ~7000 years.

    You say right after this fallacious point that many in the debate ignore geological history. Well you have not cited any with any accuracy.

    The assumption that CO2 drives temperature. Even the IPCC report touched on
    the phase relationship raised by Fischer but then simply refused to consider any
    of the latter work by others. The evidence points more and more to a lag
    relationship not a leading one!

    CO2 driving temperature is not an assumption, it is a theory. It is a theory that is consistent with all available evidence and consistent with the laws of physics and basic chemistry of gasses. This does not mean CO2 is the only driver, it does not mean CO2 is always the predominant driver. The lag between temperature and CO2 in the glacial record shows that CO2 changes are not only a cause of climate change, but they are a result of climate change. There is nothing hidden about that record, and nothing that contradicts current theory, in fact that evidence taken in totality is further confirmation that CO2 is strong climate forcing agent.

    Since you value lessons from the geological record, you should consider the PETM event.

    Again about the distant past in response to my pointing out that we just don’t know enough you said “If the models do not correlate with what we know then the models are wrong!”. What you are demanding is that the models correlate with what we don’t know. You claim models are no good if you have to use “fudge factors” (without identifying what models, what factors I might note) and now you want the models to reproduce the distant past with no data. Ludicrous!

    Since it comes up several more times in your post, I wish to state again for the record that you have yet to provide evidence for global changes in temperature of 5oC/decade. The only non-hand waves you offered are regional indicators, and they are jumps that don’t show up in the antarctic ice cores I might add.

    The assumption (and there are far too many in this debate already) had been
    that the increase in methane for the last 150 years was totally anthropogenic
    and it is probably wrong!

    Your wisecrack about assumptions is highly ironic. Not just because of so many in your post but because you follow it with two whoppers. We have recently discovered that plants unexpectedly emit methane. Now you assume that this started 150 years ago, and you further assume the issue of attribution is settled. Try this post:
    http://www.realclimate.org/index.php?p=236

    Comment by Coby — 6 Feb 2006 @ 12:53 AM

  180. Yes there was a typo it should have been 5C not 15! There is ample evidence in the ice cores, Altalntic sediments, corals and sea level changes (induced by thermal expansion not melting!). if you choose to igniore them so be it.

    But it brings up the real issue about temperatures and time. Yes out of the last ice age the AVERAGE temperature rise over 10,000 years was 6C/10,000 = .06/100. However the geological record clearly shows that at the fine scale the temperature oscillated up and down several C over hundreds and even several C per decade, more than it has over the last 100! Some of these changes were regionally more intense but there is ample evidence for global involvement as mentioned above. This is exactly as you would expect for TSI induced changes.

    This is the point: some are comparing an average over the last 100 years with an everage over 10,000! When we do compare apples to apples i.e. regional short term averages OR long term trends we find the current trend is nothing extraordinary!

    Comment by Jon Jenkins — 6 Feb 2006 @ 2:00 AM

  181. Jon Jenkins states:

    “there is ample evidence for global involvement” of “even several C per decade”.

    Care to give us a reference?

    Comment by Chris O'Neill — 6 Feb 2006 @ 4:50 AM

  182. John Jenkins wrote:

    “but for the moment everything I have read tells me that we just don’t know enough to make good decisions”

    Agree absolutely. Putting 10GT of carbon into the atmosphere every year without knowing the consequences is not a good decision.

    Comment by Chris O'Neill — 6 Feb 2006 @ 5:37 AM

  183. Re Dr. Jenkins — another point is his statement about models with slightly different initial conditions diverging wildly. In my experience, radiative-convective models of planetary atmospheres converge, not diverge. You can start with radically different profiles of temperature versus height (I have!) and get pretty much the same results. This is exactly the opposite of what is claimed.

    Yes, I know about the difference between RCMs and GCMs. My comment stands, I think. Gavin?

    Comment by Barton Paul Levenson — 6 Feb 2006 @ 8:01 AM

  184. In comment #180, Jon Jenkins wrote … “However the geological record clearly shows that at the fine scale the temperature oscillated up and down several C over hundreds and even several C per decade, more than it has over the last 100!” …

    But to me, it is no mystery that temperatures oscillate more in dry air than in humid air. Globally more humid conditions are a signature of a globally greenhouse warmed climate. Cold dry air was prevalent over large areas of the world during the Pleistocene, and most of the Holocene up to the 20th century.

    The extremely dry air of the 1930s didn’t happen in the 1990s to current, and likely won’t happen again for millions of years. (See daily high and low temperatures for Jun-Aug of 1936 compared to Jun-Aug 2005, for Park Rapids, Minnesota, at:
    http://madison.indymedia.org/newswire/display/28762/index.php

    The gap between daily highs and lows in 2005 is much narrowed than in 1936. 1936 record high daily temperatures were a result of bone dry air and clear skies. http://climate.umn.edu/doc/twin_cities/mspdewpoint.htm

    2005 summer highs and high lows were influenced by heavy greenhouse gas accumulations in the atmosphere.

    103 Years of Twin Cities Dew Point Temperature Records: http://climate.umn.edu/doc/twin_cities/mspdewpoint.htm

    How do you explain record heat and very low humidity from 1927-1936? I explained that in earlier comments in the article posted at Madison IMC. http://madison.indymedia.org/newswire/display/28762/index.php

    To view additional 100 year temperature plots in the Upper Midwest, Great Plains, Northwest and Alaska see:
    http://pg.photos.yahoo.com/ph/patneuman2000/my_photos

    Comment by Pat Neuman — 6 Feb 2006 @ 8:41 AM

  185. The requests for sources are the opposite of ‘personal’ — I ask what your sources are because I mistrust the appeal to personal authority.

    I ask for your references because I assume you get your certainty somewhere. No individual could be an expert in all the areas you make statements about.

    So where do you find the facts you rely on and are telling us here?

    You sound very sure that you have everything right, that you are in the mainstream repeating things you take for granted everyone knows.

    Often people who sound that way are indeed experts. What distinguishes them is, they can footnote. They know where their facts come from, and can give us cites to look up.

    Experts understand there are questions of misreading, of interpretation, of using outdated sources, and of simple biased reading. We can check one another, as non-experts, by reading the same primary sources.

    If you are not telling us your own personal research results, give us your published sources.

    There are two ways to try to tell a convincing-sounding ranter from an expert in the field, for those of us outside the field — see if they footnote, and read the references with others and discuss the sources.

    I’m just a reader here looking for some light on the subject.

    Comment by Hank Roberts — 6 Feb 2006 @ 1:17 PM

  186. This is the final post on this topic.

    On Computer Models
    The theory of the methods used in the GISS style models is reasonably well understood as is their limitations. When the models are reasonable within the boundary/proxy conditions and all the input/outputs are defined the system will probably behave. However this is not the case with climate, significant spectral uncertainties, absorbtion anomalies, chaotic systems, sub grid phenomena, uncertainties in initial conditions etc etc mean that at best the models are an interesting guide. If we tried to design other PDE/ODE/parametric systems (aerodynamics, fluids, electronics etc) with uncertainties like this we would be laughed at and justifiably so.

    Burger and Cubasch have recently published some interesting analysis of the various models and on Mann’s recent publications which clearly demonstrate the problems of these models both in theory and practice of alignment to observed data and statistics. I would highly recommend that interested readers obtain and read.

    For anyone to say that we should accept the current models as being representative or even close to reality and as a result to influence the spending of trillions of dollars and affect billions of lives, at this point in time, is indicative of other agendas not good science. This may/will change as better models evolve and more computing power comes on line and smaller grids are achievable.

    Nothing said above has challenged this conclusion.

    [Response: Random criticisms of admittedly imperfect models contribute nothing to the debate. Chaos, uncertainty in intitial conditions etc. are inevitable features of climate modelling and techniques have been developed to deal with these (ensembles, equilibirium runs etc.) and do not contribute as much to the uncertainty than is implicitly claimed here. You need to make a specific criticism and back it up if you want to be taken seriously. -gavin]

    On Climate History
    The climate history is clear in that oscillations of several C occur regularly on both hemispherical and global scales and in decadal periods. This is clear from ice cores (Vostok, GRIP, EPICA Dome C and numerous others), corals, sediments and other records in numerous publications on the web and in basic geological and palaeontology texts. The current warming trend when compared to the geological record (e.g. Greenland, MIS-11 etc), over the relevant timescales, shows nothing unusual and if previous similar warm periods (MIS-11, 13, 15 etc) are a guide may last for another 10,000 years!

    Nothing said above has changed this conclusion

    [Response: You are just wrong. D/O events in Greenland did not lead to global changes of 'several deg C' - they do not even appear in the Antarctica core temperature proxies for instance. Comparing the current warming period with previous stable interglacial periods is just bizarre. In the absence of any human interference, the Holocene may be expected to last 30,000 or even 50,000 years (Loutre and Berger, 2001) similar to MIS 11, but the warming from increasing GHGs is a significant extra effect. -gavin]

    [Response: Just to nit-pick a bit: they do just about appear in the Antarctic cores, but are only really visible in retrospect now people know to look for them. Also, they don't really show up in "geological" things well, not properly resolved - William]

    On the Role of CO2
    It appears that the increase in CO2 is at least mainly due to anthropogenic causes although there are still some niggling uncertainties such as how much the “naturally” increased CO2 (from the oceans, bogs etc) is contributing. It seems logical to me that some of the current warming is therefore anthropogenic.

    However the models “predict” that CO2 increase leads inexorably to significant T increases but cannot explain why CO2 levels >1500ppm did not result in catastrophic temperatures whereas of course temperatures were much the same as today during that period. Further we know of periods when the temperature and CO2 were completely out of phase.

    Predictions (by what I consider to be primitive computer models) that CO2 reaching levels of +400ppm will be catastrophic are simply not supported by the geological record!

    Nothing said above has changed this conclusion

    [Response: CO2 levels from before the period covered by the ice core records are highly uncertain, although reasonable evidence exists for high GHG amounts in warm periods like the mid-Cretaceous and Eocene. However, over geologic time changing continental configurations, volcanic impacts, asteriods, mountain formation, solar evolution etc. all have important climate impacts. In the period when we have reasonable data, say the last 400,000 years, there is plenty of evidence of CO2 impact on climate (Lorius et al, 1991). And finally, setting up strawmen arguments that models predict 'catastrophic' impacts from 400 ppm CO2 is a waste of time. Read the recent guest post on 'Can 2C warming be avoided' to understand what is actually being claimed, and why some people feel that an increase of another degree or C increases the chances of 'dangerous' climate change. I would point out that the geologic record provides no examples (none!) of CO2 levels as high as today with a Greenland ice sheet and sea levels as low as today. The last time CO2 may have been as high as this (mid Pliocene ~ 3 million years ago), sea levels were 20m higher. Even stage 5e, which may have temperatures comparable to projections for mid-century, had sea levels higher by 5 or 6 meters. -gavin]

    Comment by Jon Jenkins — 6 Feb 2006 @ 6:25 PM

  187. Re 182 “Putting 10GT of carbon into the atmosphere every year without knowing the consequences is not a good decision.”

    Sounds like an intelligent remark. But the fact remains that curbing trace GHG emissions in the manners you AGW-adherents propose (manners of a distinct old flavour, not any different really from the ones Anthropogenic Global Cooling adherents used to demand) will cause less economic growth and consequently more unemployment. In fact, a great number of countries are ALREADY implementing some of those policies. For the most part, we will never know the names or see the faces of the people who will not get a job, lose the one they have or fail to escape poverty as a result of a lower global economic growth caused by the decisions you propose. But if you were to meet some of these people, would you be able to convince them that our current scientific knowledge demanded their sacrifice?

    Comment by Mikel Marinelarena — 7 Feb 2006 @ 4:54 AM

  188. The “we can’t do it” people are really just the “we don’t want to” people and when necessity finally forces the issue, technology and innovation and policy will find the solutions simply because they must. I think the “mitigate climate change or keep prospering” false dichotomy debate could use a couple of healthy lessons from history:

    1. In 1970, the U.S. Clean Air Act Amendments required 90 percent reductions in three types of pollutants from automobiles by 1976. Despite opposition to the 1970 Amendments, a technology that allowed the regulations to be met, the catalytic converter, was invented by 1975. The invention not only decreased pollution but also gave U.S. industry patents. Neither the economy nor the automobile industry suffered due to the 1970 regulations.

    2. Thomas Midgley, the inventor of leaded gasoline and chlorofluorocarbons stated, in April, 1925, that the use of lead was “…of vital importance to the continued economic use by the general public of all automotive equipment, and unless a grave and inescapable hazard exists in the manufacture of tetraethyl lead, its abandonment cannot be justified.” Midgley himself developed antiknock alternatives to leaded gasoline, but he never needed to exploit these technologies, because lead was never regulated during his lifetime. When lead was first regulated in the U.S. in 1976, non-lead antiknock technologies were improved. Cars were immediately affordable while running without knock or lead, proving Midgley incorrect.

    [note: the above two edited excerpts stolen from here: http://www.stanford.edu/group/efmh/bush/ ]

    (any other apropos examples out there? I’m sure the same economic catastrophy was predicted as a consequence of protecting the ozone layer, would like to see some quotes or details)

    Comment by Coby — 7 Feb 2006 @ 1:48 PM

  189. “Neither the economy nor the automobile industry suffered due to the 1970 regulations”

    This assertion (nothing catastrophic happened, ergo no one suffered!) comes to illustrate my point very well. Since we will never know the names of the people who could have got a job or raise from poverty but never had the chance to, we can gladly propose massive regulations on a global scale. In fact, it’s a very old economic fallacy, perfectly illustrated by Bastiat, Hazlitt and so many others. I can’t blame you for falling in it.

    But unfortunately pure economics are out of this debate and all I’d like to learn is whether sceptic scientists’ opinions are well founded or not. To that respect, the question I posed in #171 (or rather the question I rephrased and reiterated) remains unanswered. So perhaps I should conclude that they are: the lower troposphere does not seem to warm as much as the surface, so something must be wrong with the AGW theory.

    [Response: Its been the last-gasp of the skeptics for a while, but they have been obliged to abandon it. Coby has pointed you to the RC post; the wiki page has the up-to-date data and refs if you want to follow it up. Current status of the debate appears to be: AGW theory, climate models and sfc record: 1. S+C MSU record: 0 - William]

    Comment by Mikel Marinelarena — 7 Feb 2006 @ 2:43 PM

  190. Re 189 You are correct, Mikel, to conclude that there is something wrong with the AGW theory, but you are mistaken in assuming that it means we should take no action. The Arctic sea ice and the Greenland ice sheet are melting much faster than the models predict, and it is clear to me that the models are underestimating the dangers, not overestimating them as you so blithely assume.

    As far as the economic consequences of reducing the use of fossil fuels are concerned, you seem to have less evidence about that than the climate scientist have about their science. Even George W. Bush recognises that vast sums of money are flowing out of the US to pay for imported oil. If that money was retained in the US it would provide more jobs there, not less. Speculation about hypothetical unemployed workers is just scare tactics and tantamount to moral blackmail.

    Comment by Alastair McDonald — 7 Feb 2006 @ 3:15 PM

  191. # 189,

    I guess it is indeed fair to say that there is a problem between some of the tropospheric temperatures as measured by satellites and as predicted by models. It is quite thouroughly discussed here:
    http://www.realclimate.org/index.php?p=170

    But what to conclude from that? So far, errors and corrections keep getting discovered and added and the models are proving more accurate. So at the very least we must say the jury is still out. And what if the measurements continue to show this inconsistency? Then the conclusion will be the models are wrong on this aspect.

    Does this shake up the climate science community? Yes. Does this impact policy decisions? I can’t see how so.

    As for your point that we will never know who lost their job, I suppose that’s fair, but it is easily countered by the fact that we will likewise never know who gained a job because of new initiates. The point is that the overall numbers were not impacted.

    Likewise if we finally get really serious about emissions reductions, I don’t doubt that jobs will be lost, but I do doubt that there will be no compensating growth in other economic niches to offset it. Why in the world would there not be a net gain in economic activity with so much infrastructure to modify or replace and so much new technology to develope and refine?

    And as Alastair points out, finding a flaw in the theory by no means guantees that the prognosis will improve, it can just as easily indicate an underestimation in overall impacts on human lives.

    Comment by Coby — 7 Feb 2006 @ 4:34 PM

  192. > 188, predictions of economic catastrophe

    One of the classics:

    “OZONE AND GLOBAL WARMING: ARE THE PROBLEMS REAL? — Sallie Baliunas

    “Dr. Baliunas: …. Federal regulations in 1990 were costing Americans $395 – 510 billion, or nearly $5000 per household, annually. The burden of regulations is about to ratchet up. One expensive increase will result from removing chlorine-containing refrigerants, such as Freon and other CFCs, from society. CFCs are thought to gradually erode the ozone layer of the stratosphere. The bare cost of replacing or retrofitting equipment is roughly $100 billion …. A short-term cost of $2 trillion will rip through the U.S. economy according to a 1993 estimate contained in House Resolution 291. ….”

    Full document here as PDF file:
    http://johnquiggin.com/wp-content/uploads/2006/01/baliunas_report.pdf

    Mentioned here:
    http://johnquiggin.com/index.php/archives/2003/09/14/junk-science-on-ozone/

    Comment by Hank Roberts — 7 Feb 2006 @ 5:19 PM

  193. Re: 190

    The most recent study I’ve heard of says that the Greenland ice mass balance is increasing in the interior and decreasing at the edges. Total mass balance still seems “up in the air”, and not “melting faster than the models predicted”. The article below says that parts of the interior above 1500 meters are accumulating snow at something over 6 cm annually. Areas below 1500 meters elevation are losing ice at a rate of approx. 2 cm per year. The average thickness of the Greenland ice sheet is 2.3 kilometers.

    To quote another part of the article:

    “Modelling studies of the Greenland Ice Sheet mass balance under greenhouse global warming have shown that temperature increases up to about 3ºC lead to positive mass balance changes at high elevations “due to snow accumulation” and negative at low elevations – due to snow melt exceeding accumulation.

    Such models agree with the new observational results. However after that threshold is reached, potentially within the next hundred years, losses from melting would exceed accumulation from increases in snowfall “then the meltdown of the Greenland Ice Sheet would be on.”

    This statement sounds rather alarming. Rather than quibble with it, let’s assume it’s true. The time required to melt the entire sheet (or an appreciable fraction of it) would have to be measured in millenia, even assuming a massive increase in the rate of loss. If the “average” depth of the sheet is 2.3 kilometers, then if the entire sheet started losing 2 cm per year it would take 115,000 years for it to disappear. So let’s assume there’s some kind of positive feedback loop that increases the rate of loss by a factor of 10. It would still take over 11,000 years for the entire sheet to melt. This particular “danger” of global warming doesn’t seem to be particularly imminent.

    Of course, the article also very correctly points out that short-term trends shouldn’t be used to make long-term predictions.

    http://www.eurekalert.org/pub_releases/2005-11/esa-eas110405.php

    Cheers.

    Comment by Ken Robinson — 7 Feb 2006 @ 6:09 PM

  194. Ken, the sudden acceleration of two additional glaciers was news at the December 2005 AGU, I recall. One had sped up some years ago and was thought to be an anomaly. (“Once is happenstance, twice is coincidence, three times is enemy action” comes to mind — it does suggest something new going on that wasn’t expected.)

    Here’s a bit newer source:
    http://www.ume.maine.edu/iceage/Research/Contrib/html/08.html

    Comment by Hank Roberts — 7 Feb 2006 @ 7:41 PM

  195. http://www.nasa.gov/vision/earth/lookingatearth/grace-20051220.html
    “In an update to findings published in the journal Geophysical Research Letters, a team led by Dr. Isabella Velicogna of the University of Colorado, Boulder, found that Greenland’s ice sheet decreased by 162 (plus or minus 22) cubic kilometers a year between 2002 and 2005. This is higher than all previously published estimates, and it represents a change of about 0.4 millimeters (.016 inches) per year to global sea level rise.”

    That is a correction on what seems to be happening at the moment. As for your projections into the future, you don’t know the first thing about the dynamics of ice sheets. So aside from the naive linear extrapolations based on…what exactly? history tells us a little about ice sheet collapses and my understanding is that the can happen surprisingly fast. I can’t find the quote but I do recall reading at least one researcher saying we may be looking at a few centuries or faster, not one or two millenia.

    Comment by Coby — 7 Feb 2006 @ 7:50 PM

  196. Re #189: Apparently we are supposed to imagine some fantasmagorical amount of economic growth that would have occurred if only we had never adopted the Clean Air Act, the Montreal Protocol, etc., etc.? Sounds pretty unlikely to me.

    What is more likely is that entrenched special interests have a strong incentive to exaggerate the costs and minimize the benefits of such environmental regulations and they find willing accomplices in libertarian-leaning economists, politicians, and think-tanks. And, interestingly enough, even organizations like the EPA seem to consistently overestimate the costs of compliance with environmental regulations, presumably because they don’t take into account the innovative least-cost ways that the market will come up to comply. (See http://www.prospect.org/print/V8/35/goodstein-e.html .) Yes, market economic theory continues to work even in a world with certain regulations despite the libertarians’ attempts to convince us that it only works if we let the market run free with all the rampant externalities and all…Go figure!

    Comment by Joel Shore — 7 Feb 2006 @ 8:07 PM

  197. Here’s (from a Google cache) a proposal draft for a 2007-2008 “Polar Year” study — the summary says a lot about what we don’t know yet and could find out. It’s from NASA personnel, perhaps someone can tell us more?

    http://www.google.com/search?q=cache:ZpxG72006YUJ:www.ipy.org/development/eoi/details.php%3Fid%3D951+Greenland+mass+balance&hl=en&gl=us&ct=clnk&cd=51&client=firefox-a

    Quoting a chunk from that [my excerpts and formatting]:

    “… The airborne data, however, do not cover all outlet glaciers, and satellite radar altimetry does not cover coastal ranges where most changes take place. As a result, published estimates of the mass balance of the Greenland Ice Sheet are underestimates.”

    “Moreover, recent analysis suggests that changes in velocity of the glaciers contribute for more than half of the observed mass loss, but such velocity changes cannot be measured with altimetry.”

    “Another approach to mass balance is the mass budget or component method where mass outflow at the grounding line – calculated combined information on ice velocity and thickness – is compared with net accumulation upstream. …. ice thickness data are remain too sparse to measure outflow on all glaciers.”

    “In the next two years, we will collect the necessary thickness data using the NASA P3 to estimate 2000 ice fluxes from Radarsat-1. During IPY, we will not re-measure ice thickness but we will re-measure ice velocity…, around the entire periphery of Greenland, except local ice caps. These new and old data will be used to estimate mass balance of all the major Greenland glaciers and changes between 1992, 1996, 2000, and 2008.”

    “This is be important to determine the contribution to sea level rise of Greenland as well as identify the contribution to mass imbalance from changes in ice velocity of the glaciers. It will also identify the glaciers that are contributing the most to the imbalance of the Greenland ice sheet. Analysis of the results will be done jointly with colleagues in Denmark.”

    “PROPOSER — Dr Eric Rignot Jet Propulsion Laboratory”
    ——

    I hope they got funded — it was to be decided in 2005. If so, I suppose they can’t say anything before they publish. Must … be … patient.

    Comment by Hank Roberts — 7 Feb 2006 @ 8:08 PM

  198. Re #189: “To that respect, the question I posed in #171 (or rather the question I rephrased and reiterated) remains unanswered. So perhaps I should conclude that they are: the lower troposphere does not seem to warm as much as the surface, so something must be wrong with the AGW theory.”

    Ah, the irony of it all! Do you realize that you are basing your entire assertion on your interpretation of the data in the figures from a draft report and yet if you go and read the executive summary of the draft report itself (available here: http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/sap1-1prd-exsum-no-figs.pdf ), it contradicts your interpretation of the data:

    “During the satellite era (1979 onwards), both the low and mid troposphere have warmed. The majority of data sets show warming at the surface that is greater than in the troposphere. Some data sets, however, show the opposite â�� tropospheric warming that is greater than that at the surface.”

    “For global-mean temperature changes in the new climate model simulations, some show more warming in the troposphere than at the surface, while a slightly smaller number of simulations show the opposite behavior. Given the range of observed results and the range of model results, there is no inconsistency between models and observations at the global scale.”

    “[In the tropics,] the majority of observed data sets show more warming at the surface than in the troposphere, while some newer observed data sets show the opposite behavior. Almost all model simulations show more warming in the troposphere than at the surface.”

    “In the tropics, the agreement between models and observations depends on the time scale considered. For month-to-month and year-to-year variations, models and observations both show amplification (i.e., the month-to-month and year-to-year variations are larger aloft than at the surface). The magnitude of this amplification is essentially the same in models and observations. On decadal and longer time scales, however, while almost all model simulations show greater warming aloft, most observations show greater warming at the surface.

    These results have at least two possible explanations, which are not mutually exclusive. Either amplification effects on short and long time scales are controlled by different physical mechanisms, and models fail to capture such behavior; and/or remaining errors in some of the observed tropospheric data sets adversely affect their long-term temperature trends. The second explanation is judged more likely.”

    So, now that your own source contradicts your interpretation of this being necessarily a big problem with the models (let alone with all of AGW theory), perhaps you’ll give up your claims? Or, is that source no longer looking so trustworthy to you?

    Comment by Joel Shore — 7 Feb 2006 @ 8:28 PM

  199. Re #187

    “we will never know the names or see the faces of the people who will not get a job, lose the one they have or fail to escape poverty as a result of a lower global economic growth caused by the decisions you propose”

    There is no law of economics that says that avoiding using the burning of carbon will result in lower employment. What economics does say is that if additional economic resoures are used to produce energy supplies than otherwise then those economic resources will not be available for some other purpose. So yes using non-carbon-burning sources of energy will cost us some money so that’s what the argument is really about. The factor that skeptics ignore is risk. Skeptics always talk as if the risk of damage from CO2-caused global warming is zero without justifying how they come up with a figure of zero. e.g. they effectively say the risk of damage from an extra 10GT of carbon into the atmosphere every year is zero.

    Comment by Chris O'Neill — 8 Feb 2006 @ 2:20 AM

  200. Re 193

    If you go to http://news.bbc.co.uk/1/hi/sci/tech/4660938.stm â??Stark Warning over Climate Changeâ?? and click on the map of Greenland you get the following map;

    http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/06/sci_nat_enl_1138619023/img/1.jpg

    It shows that the areas which are melting are expanding into the areas where the snow is accumulating. If those melt areas continue to grow at the SAME rate, then they will have almost doubled by 2012, and nearly halved the areas where snow is accumulating. If the melting is being caused by increased greenhouse gases raising the snow line, then it is likely that their growth will accelrate rather than remain the same, since the greenhouse gas concentrations are increasing. That is without the ice albedo positive feedback effect, which will cause an acceleration even if the increase in greenhouse gas concentration is halted.

    Let’s face it, the only way to stop the Greenland ice melting would be to reduce, not just our consumption of fossil fuels, but also their atmospheric concentration.

    Cheers, Alastair.

    Comment by Alastair McDonald — 8 Feb 2006 @ 6:25 AM

  201. I notice that some of the comments are a bit too confrontational. Indeed it makes me think that we’re not just talking science here, but ideology as well. Which of course is legitimate but not very helpful at all. In any case, Joel, I appreciate your spending your time to finally satisfy my curiosity and provide with an explanation for the contradiction I had observed. I do find this source pretty reliable, which is why I used it. Not only it showed what seemed to be recent data but it also included various independent measurements (I think that, in fact, we’re all using the same raw data, aren’t we?). The summary you so kindly provided clearly acknowledges and addresses the apparent contradiction and concludes that either physical fenomena exist that the models are not taking into account or tropospheric data need (still further) correction, or both. Quite short of the one-to-nil claim of William’s, I’d dare to say. Besides, I had been told above that the contradiction didn’t exist at all.

    Alastair: not only there are recent studies showing that the Greenland ice-cap is actually growing (but of course someone has hastened to show studies indicating the contrary: this is like a trenches war!) but apparently the same is happening in Antarctica, with an accompanying cooling over the continent included. As for the Arctic sea ice cover, it is becoming smaller in summer and then recovering to the usual dimensions in winter. I won’t bother digging for my sources here, as I’m sure someone will quickly find studies showing that the contrary is true. In any case, I’m sure you know that the Arctic sea ice cover poses no risk at all from the sea-level rise perspective, even if it were to melt completely (which, considering the tilt of the earth, would require a tremendous warming not still predicted by any serious study that I know of).

    Coby and Hanks: if the possibility existed of a net economic gain from shifting now from a source of energy to another, no regulations would be required at all. It would be happening before our very eyes, driven by the energy-producing companies themselves competing against each other (if allowed to). I think that my point can be illustrated rather easily. Let’s imagine, for simplicity, that what is now being proposed is that governments impose a 5% cut in GHG emissions on industry. Not so terrible, you seem to think. Ok, but what about imposing a 50% cut? Would that not make a huge amount of different industries simply shut down, not being able to cope with the cost of such a regulation? Would that not make energy tremendously more expensive? Would it not, in summary, bring about an economic catastrophe? So, if we agree on this obvious point, at what point does an emission cut of x% turn from a catastrophe to a major economic disruption and when does it become a hurdle that will ‘only’ generate less profits, less growth (and yes, unavoidably less employment)? I don’t think that the existence of a cost for any GHG emissions cut is something debatable. Of course, if governments tax the industries or the economies as a whole they can generate revenue with which to create new jobs, say in research or new technologies, but the net economic result will necessarily be negative until more efficient energy-producing technologies are discovered, for which no regulation was required in the first place. And this is so for at least 2 reasons: a) Governments can’t spend as much as they tax, because the very taxation procedure is a (bureaucratic) cost to be deducted from the revenue. b) More importantly, by altering the market prices through taxation the scarce resources will be allocated in an inefficient manner: if GHG-emitting industry is taxed $1 bn by the government, which in turn invests $1 bn in new technologies (and we already know that it will be less than $1 bn) the gains created in the 2nd process will not be enough to compensate for the losses created in the 1st process, for the same reason that if someone destroys the windows of your house the gain for the glaziers when you spend your money repairing them will not compensate for the losses you had to incur in, when you were actually planning to spend (or save) your money in better things.

    But of course, Western economies and big corporations will surely be able to cope with Kyoto-1, no questions about that. It’s just the most vulnerable who will bear the cost, as usual.

    Comment by Mikel Marinelarena — 8 Feb 2006 @ 10:43 AM

  202. #200 Alastair, I agree we must do what seems to be impossible, reducing CO2, but even harder would be to convince most people to act on it.. #201- Mikel, switching to Hydrogen would be extremely benificial to countries importing oil, making manufacturing of Hydrogen completely homegrown, it would fuel an unprecedented economic revival. for the US, imagine 20% Hydrogen industry, this would make an investment of $50 billion a year strictly in the US, from production to distribution, everything local…

    Comment by wayne davidson — 8 Feb 2006 @ 11:23 AM

  203. #201: “The summary you so kindly provided clearly acknowledges and addresses the apparent contradiction and concludes that either physical fenomena exist that the models are not taking into account or tropospheric data need (still further) correction, or both. Quite short of the one-to-nil claim of William’s, I’d dare to say. Besides, I had been told above that the contradiction didn’t exist at all.”

    Not at all. Christie and Spencer have had to correct their calculations more than once, after other people pointed out their errors and after they stubbornly defended those errors over a period of time. The satellite data now agrees with other data and model predictions within the error bars of uncertainty. And the people who’ve found past errors in C & S have run their own calculations that make the data correspond even closer to model predictions. Given the fact that C & S, when challenged over errors, have each time been proven wrong, they have little credibility left in my mind. When you make silly little errors like flip the sign of a numeric entity, you tend to lose credibility. Life’s like that.

    In short, the contradiction only existed in the sense that proofs that 1 = 0 exist – bad mathematics. The contradiction was based on errors in their analysis, in at least one instance a mathematically trivial and most embarrassing error.

    “Coby and Hanks: if the possibility existed of a net economic gain from shifting now from a source of energy to another, no regulations would be required at all. It would be happening before our very eyes”

    That’s naive economic thinking. That’s like saying “if it were possible to make money over a cheap, worldwide public computer network private industry would invent it”. Well, it was possible, and government, not private industry, invented it and private industry only took it up when legislation allowed for commercial entities to partake and sell services to consumers. Private industry for the most part wasn’t even asking to be part of it. They didn’t share the vision that a lot of money could be made off it. A decade later, an entire new Internet-based economic realm was borne and still grows today.

    Comment by Don Baccus — 8 Feb 2006 @ 1:58 PM

  204. if the possibility existed of a net economic gain from shifting now from a source of energy to another, no regulations would be required at all. It would be happening before our very eyes, driven by the energy-producing companies themselves

    I’m sorry to be so dismissive about this, but it just strikes me as believing in fairy tales. The net economic gain, that I am claiming is just as likely as loss, from a major shift in energy usage also entails major shuffling around of industrial wealth. If you are an energy company in today’s paradigm making, oh let’s say $36.13 billion profits (not revenue) in a single year, why in the world would you be interested in risking your current market position in the least, even considering the fact that you are ideally positioned to dominate in the new paradigm? If you are an innovator with a new fantastic idea that will benefit the consumer but reduce the fossil fuel market, it is more likely that santa clause really exists than you will not meet with opposition from very powerful industry and political forces (oh, look! they are the same people!).

    Think for a moment about Los Angeles, the auto industry and the rail system. Why are millions of productive people hours spent alone in an empty car in traffic jams, why is the air so polluted by exhaust fumes, why is there no light rail public transit system? Because the auto industry bought the rails just to ensure no one could ever use them. That is free market at work. And that results in a loss of quality of life, loss of worker productivity, loss of resources dealing with the effects of pollution.

    Ok, but what about imposing a 50% cut? Would that not make a huge amount of different industries simply shut down, not being able to cope with the cost of such a regulation? Would that not make energy tremendously more expensive? Would it not, in summary, bring about an economic catastrophe?

    I know you followed this with “if we can agree on this obvious point” but I’m afraid I can’t. There are assumptions built into it that need closer scrutiny. For one thing, what time frame are we talking about? Perhaps on the short term some of what you describe would indeed occur (perhaps not) but I think on the long term things will adjust themselves.

    As leary as I am of the utility of such general handwaving as you use above, I am about to respond with the same. So the government imposes a 50% cut, it makes a huge difference and some industries shut down (I am accepting under protest that these industries do not adapt but rather quit). Well, didn’t these industries provide some good or service? Now according to free market principals the demand for these missing goods will skyrocket. So along comes an innovator and entrepreneur with a plan for an alternative or low energy way to provide for this demand and a new company is born. The new infrastructure that is suddenly in demand means more engineering and construction contracts, which demand more manufacturing, all these workers now have more spending money and the demand for luxury goods goes up etc etc.

    Presumably, government would impose these cuts via large taxes, and this would create financial resources that can then be diverted to help the innovators and the adapters, the dinosaurs die out, too bad that’s a) evolution and b) the necessary price for the health of planet and society.

    That strikes me as much more plausible than we all sit on our hands and weep because things are now different.

    Though I appreciate what you are saying, I don’t really find the rest of your post convincing. The bureaucracy is already in place, any additional administrative costs are going to be pennies compared to hundred dollar bills. Repairing the broken window is more economically productive than me saving my money and equally so for me spending it buying something else. (Mind you I don’t buy all the economic gibberish that makes that so, but that is the frame we are speaking within).

    But all these discussions aside, we have to deal with the question “is it necessary?” first. The interruption of that debate with maoning about how expensive it will be is the way a teenager decides what must be done. How hard is it? Oh, well I don’t really need it. That is not the rational way to deal with it. The economic cost of uncontrolled emissions will be huge even if an African is only worth a fraction of what an American is worth
    in the balance sheets of the World Bank.

    Where is that supposedly American “can do” attitude? “We have to drastically reduce CO2 emissions, now!” “Ok, let’s roll.”

    Comment by Coby — 8 Feb 2006 @ 2:05 PM

  205. Re #203 Don: why is the US Climate Change Science Program still accepting C&S’s measurements? But still, we can leave them out, if that makes you more comfortable. I continue seeing a 5 to 1 measurements difference in favor of less warming in the lower troposphere than on the surface, according to the graphs published and commented by that institution (of course I am aware that what I’ve just typed would only be a preliminary assessment based on rudimentary arithmetic and subject to correction by a properly worded summary!!).

    Yeap, you can have a technology developed not by private but by public funded research, and then rapidly used by the private sector in order to make profits and satisfy our wants (the history of the internet, among others). So what?

    Re #204 Coby: if you’re not convinced by the arbitrary 50% figure I chose just put any other high enough. My reasoning holds equally well. As you said, this is not so important, I brought it up because I was reading that curbing CO2 emissions would have NO cost. So you can disagree from my economic views as much as you want, it doesn’t matter. Still, if you follow your reasoning to the end you’ll find that you’re basically proposing that we all smash the windows of our houses in order to create a buoyant glazier industry, which will indeed generate direct and indirect jobs, create demand for perhaps the goods we produce ourselves, develop brand new window-repairing technologies, etc…

    Comment by Mikel Marinelarena — 8 Feb 2006 @ 3:08 PM

  206. > net economic gain … [worldwide Internet example]

    I can remember seeing projections made — in the 300-baud dialup days — by my local telephone provider, of profits anticipated from the increasing use of dialup modems and the popularity of “bulletin board” systems.

    They calculated the rate of increasing popularity, the total number of individual calls, local and long distance, and the connect time required at 300 baud, and projected a very nice profit from the development over the coming decade or two.

    Individual businesses handle technological change in local terms.

    > smash the windows … to create [economic benefits]

    This in fact counts toward the Gross National Product calculation. The more disasters, the higher the GNP.

    Comment by Hank Roberts — 8 Feb 2006 @ 3:54 PM

  207. Re #202 by Mikel Marinelarena — Sir, you are assuming there are no costs to global warming. If there are, the loss from switching energy sources might conceivably be less than the loss from not doing so. Until you justify your assumption that staying with fossil fuels has no costs, your whole argument fails.

    Comment by Barton Paul Levenson — 8 Feb 2006 @ 5:26 PM

  208. Still, if you follow your reasoning to the end you’ll find that you’re basically proposing that we all smash the windows of our houses in order to create a buoyant glazier industry, which will indeed generate direct and indirect jobs, create demand for perhaps the goods we produce ourselves, develop brand new window-repairing technologies, etc…

    Heh. If I may ensure we have stretched the analogy far beyond it own shattering point: my argument is that there is no way out of the house, we must smash the windows, others are worried about the economic damage caused by doing so. I let the rest of your description speak to my point!

    Cheers,

    Comment by Coby — 8 Feb 2006 @ 7:15 PM

  209. Re #201

    “there are recent studies showing that the Greenland ice-cap is actually growing”

    The use of cherry-picked and carelessly interpreted statements like this is a common denialist technique. Of course the Greenland ice-cap is growing thicker where the temperature is well below freezing. This is what you’d expect in such places with warmer and consequently more humid air. The fact ignored by denialists is that Greenland is shrinking at the edges where you’d expect it to melt first. I guess all we can expect from denialists is to endlessly throw up cherry-picked and carelessly interpreted statements like the above.

    Comment by Chris O'Neill — 8 Feb 2006 @ 11:02 PM

  210. Re #205: Mikel, I answered your concern about the CCSP report way back in comment 170. The language used by the authors is a bit elliptical and perhaps not obvious to someone who isn’t a native English speaker, but nonetheless it is clear. If the conclusions of the authors aren’t enough for you, I’m afraid you’ll have to read the entire report. I would be willing to discuss it more after that.

    Comment by Steve Bloom — 9 Feb 2006 @ 1:58 AM

  211. RE No. 209. “The use of cherry-picked and carelessly interpreted statements” is certainly not good argument. So you have taken one short phrase out of a 4-paragraph comment and attacked it, out-of-context with un-substantiated statements. Where are your references?(a request we so often hear to those who dare challenge the AGW case). Its this type of attitude that most damages the pro-AGW argument.

    Comment by PHEaston — 9 Feb 2006 @ 8:00 AM

  212. Re #211

    The one short phrase stands on its own without context as you would see if you read the context. The study about the Greenland ice-cap was probably Recent Ice Sheet Growth in the Interior of Greenland which says

    “The averaged results indicate a net increase of 6.4 cm/year in the interior areas above 1500 m. Below 1500 m, the elevation-change rate is -2.0 cm/year, in qualitative agreement with reported thinning in the ice-sheet margins.” The summary implies that there is about 0.5 cm/year bedrock uplift. The summary concludes by saying

    “Modeling studies of the Greenland Ice Sheet mass balance under greenhouse global warming have shown that temperature increases up to about 3C lead to positive mass balance changes at high elevations (due to accumulation) and negative at low elevations (due to runoff exceeding accumulation), in agreement with these new observational results. However, after that threshold is reached, possibly already in the present century, losses from melting would exceed accumulation from increases in snowfall – then the meltdown of the Greenland Ice Sheet would be on.”

    You can also check http://news.bbc.co.uk/1/hi/sci/tech/4660938.stm which refers to “Arctic Climate Impact Assessment” published by the UK Government to see how the area of Greenland’s summer melt zone has increased. Click on the Greenland map. This reference had already been mentioned in #200.

    Comment by Chris O'Neill — 9 Feb 2006 @ 12:50 PM

  213. PHEaston,

    I believe I provided the reference above showing Greenland losing ice mass:

    http://www.nasa.gov/vision/earth/lookingatearth/grace-20051220.html
    “In an update to findings published in the journal Geophysical Research Letters, a team led by Dr. Isabella Velicogna of the University of Colorado, Boulder, found that Greenland’s ice sheet decreased by 162 (plus or minus 22) cubic kilometers a year between 2002 and 2005. This is higher than all previously published estimates, and it represents a change of about 0.4 millimeters (.016 inches) per year to global sea level rise.”

    Which was a response to another poster simply “recalling” studies but providing no references. So I may be missing something, let me know, but so far I am not aware of any references being provided to support the notion that Greenland ice is showing ant net increases.

    As for context, the “4 paragraph comment” only dealt with Greenland in one paragraph, and comment #209 certainly presented enough to fairly characterize it so your attack is a little questionable.

    Comment by Coby — 9 Feb 2006 @ 12:59 PM

  214. Re: #211 [PHE]

    If I may,

    My comment here is your answer wrt Greenland [currently# 100]. In a nutshell: 1., 2., 3., 4. , 5., 6., 7. (the context for the issue).

    This is all, of course, common knowledge and we shouldn’t expect Mr O’Neill to have to provide atomistic detail for every statement, esp. for topics that we should all know; That is: if you don’t know this, then the highlighted statement in 209 is the crux of the competence of the arguer and its use is easily justified (not that I’m doing it, but I had the information you seek on my clipboard and the argumentation is so simple to interpret).

    HTH,

    D

    Comment by Dano — 9 Feb 2006 @ 1:22 PM

  215. Coby:

    Re: 195

    Of course I don’t know anything about the dynamics of ice sheets. I rather doubt that anyone here knows the first thing about the dynamics of ice sheets. That doesn’t preclude the application of simple common sense.

    The Greenland ice sheet’s thickness is measured in KILOMETERS. Scientists are debating its mass gain and loss in terms of CENTIMETERS, and the total mass balance still seems to be in debate. The reference I provided indicated that most models predict a GAIN in total mass under global warming scenarios for a considerable period into the future.

    But let’s set THAT reference aside, and take at face value the numbers in the reference you prefer, of a loss in ice mass of 162 cubic kilometers annually. Shocking. Alarming. Now let’s look at the size of the ice sheet in question. According to the Encyclopedia Brittanica;

    “The largest ice sheet, the Greenland Inland Ice, is second in area only to the Antarctic Ice Sheet. It extends about 1,570 miles from north to south and has a maximum width of some 600 miles and an average thickness of about 5,800 feet, reaching 11,000 feet in the middle of the island. It covers an area of more than 650,000 square miles, nearly 80 percent of Greenland, and is contained within a basin by the mountains around the margins.”

    If I’ve done my sums correctly, that’s a surface area of about 1.68 million square kilometers, with an average depth of about 1.77 kilometers. 1.68 million times 1.77 is just under 3 million cubic kilometers. That’s a lot of ice.

    One of the references Dano provides states that:

    “The Greenland ice sheet may disappear within about 1,000 years, raising Earth’s sea level by about 20 feet, and the glacial breakdown mechanisms being studied could speed that up considerably.”

    Coby, you say that one of the researchers you “recall” suggests a timeframe of a few centuries. But let’s not be too pessimistic, and let’s use a thousand years as a nice round number.

    Hmmm. To melt all that ice in the space of a thousand years would require a loss of 3 million km3 divided by 1000 years equals 3000 cubic kilometers per year. That’s a rate of loss 18 times greater than the loss cited in Coby’s reference (which is “higher than all previous estimates” and therefore more accurate I suppose. It’s contradicted by my reference, but so what).

    You say linear extrapolations are naove (although the loss rate cited in your reference seems to be a simple linear regression of the data, for all of three years). Fair enough. Let’s take the opposite approach. Explain to me please, how we’re going to go from losing 162 km3 to an AVERAGE of 3000 km3 annually. That’s one heck of a feedback loop. And keep in mind, Coby, that we’re not going to see 3000 km3 of ice loss anytime soon (ie not in the next year, or decade, or century). Therefore, logically there will have to be an even more vastly accelerated rate of loss in the future if we’re going to get rid of the entire ice sheet anytime before 3000 AD. What will cause such an exponential rise in the melt rate? Where are the data to support such a proposition? Perhaps we can find an expert in ice sheet dynamics who can explain it to us in detail…

    And by the way, according to a survey of Greenland’s temperatures published in the International Journal of Climatology (http://polarmet.mps.ohio-state.edu/jbox/pubs/Box_2002_Greenland_Temperature_Analysis.pdf) , the SUMMER mean temperature in the middle of Greenland (where the ice is thickest, averaging something like 3 km deep) is -14.9 degrees C. The annual mean temperature in this location is -29.7 degrees. Clearly, this ice will never melt. The only way to get the WHOLE sheet to melt is to move ALL the ice to the edges and melt it there. That’ll be a neat trick for an ice sheet “contained within a basin by the mountains around the margins”. Sure, parts of it can flow down to the coast. But ALL of it? Again, I would ask for help from an ice sheet dynamics expert in understanding how this will happen, since my amateur brain is incapable of developing a scenario to account for this…

    I’ll just mention in passing that the same survey of Greenland temperatures (almost all of which are coastal sites) did in fact find a significant warming trend over the 20th century. It appears that the majority of this warming occurred prior to 1940. In fact, some of the temperature increases back in the 1930′s must have been very alarming, since they match (or even exceed) today’s observed temperature increases in terms of rate and magnitude. It’s astonishing that civilization survived, really.

    But I digress…

    I know, I know. Glaciers will flow faster, and melt faster, and big chunks will come flying off. Well, maybe. But I haven’t seen any actual data, nor a plausible mechanism, in the literature, or the references provided to me, to indicate that 3 million cubic kilometers of ice will disappear in a thousand years. Or, as you “recall”, a few centuries.

    I’m not saying some ice won’t melt. I’m not saying that big chunks won’t come off. I’m simply saying that the vast bulk of the Greenland Ice Sheet is going to be around for a long, long, long time. Go ahead; call me naive some more.

    Cheers.

    Comment by Ken Robinson — 10 Feb 2006 @ 3:27 PM

  216. About the Greenland ice cap:

    The retreat of the ice cap in Greenland is mainly at the edges and is directly coupled with summer temperatures around Greenland. Most of the ice cap in the centre is too high and doesn’t get melting temperatures, not even in summer. As temperatures get higher, the increased humidity also increases snowfall (as is also the case in Norway, where glaciers are growing).

    Of more interest is to have a look at the history of Greenland glacier retreat and temperatures. All Greenland stations are at the edges, as the inland ice is uninhabitable.
    From the largest Greenland glacier in Ilulisat (Jacobshavn) the breakup point (where the glacier breaks into icebergs) is known since 1850. The move of the breakup point to more inland is probably the direct result of warmer temperatures.
    The move of the breakup point started already before 1850 and was fastest in the period 1929-1953, before GHGs had much of their influence. Moreover, the Greenland temperatures after 2000 just reach the temperatures seen in the 1930-1940′s, with a cooler climate in between (which seems to be connected to the NAO)…
    As the breakup point moves, the counterpressure/resistance reduces and the glacier is moving faster. I suppose that is the case for all Greenland glaciers now.

    It seems to me that the NAO has more influence on the Greenland glacier melting than general global climate, and that GHGs played a minor role, based on the long retreat of the glacier and the fact that the melting was faster in the 1930-1940′s.

    Comment by Ferdinand Engelbeen — 10 Feb 2006 @ 6:44 PM

  217. Re #215

    “the SUMMER mean temperature in the middle of Greenland (where the ice is thickest, averaging something like 3 km deep) is -14.9 degrees C. The annual mean temperature in this location is -29.7 degrees. Clearly, this ice will never melt.”

    I’m not a glaciologist but I do know some things about Greenland that make the above a brave assumption. The middle of Greenland has about 3km of ice and it is also about 3km high. As you might guess, this means the bedrock is not very far from sea level and in fact a lot of it is below sea level. Without the ice Greenland would be like a large lake surrounded by land most of which is fairly high. So even though the ice in the middle may never melt as long as it stays 3km high, it’s a different story if for any reason that ice was reduced to a lower altitude, say 1.5km. It’s interesting to see that some research has shown that if the ice was removed from Greenland, it would not re-establish the ice-cap at current or pre-industrial temperatures. So the ice-cap on Greenland is a bi-stable or hysteresis process and thus there is some critical temperature above which the ice-cap will proceed to disappear. No-one knows what this temperature is but James Hansen offered the guess that it is probably at least 2 degrees C. This say nothing about how long such melting takes. It’s hard to say because melting is such a non-linear process. One other thing James Hansen said was that the ice-cap melting process rapidly accelerated as it proceeded, so it is very slow to begin with and very fast towards the end.

    Comment by Chris O'Neill — 11 Feb 2006 @ 11:48 PM

  218. Re #217:

    According to different models, the increase of sea levels due to melting Arctic icefields/glaciers is between 0-6 cm for this century. See Oerlemans ea.. But that is based on a constant increase of GHGs/temperatures. In the case of the Greenland ice cap, that is far from settled. For the mean yearly average temperature trends (of the edges), the 2000+ temperatures hardly reach the 1930-1950 trends, but the more important summer (June-July-August) temperatures still seems to be below the 1930-1950 level. See the until 2005 updated Greenland temperature trends.

    Comment by Ferdinand Engelbeen — 12 Feb 2006 @ 9:00 AM

  219. Re 217

    Chris, thanks for the note. Maybe I’m just dense today but I’m having difficulty following what you’re saying. You say “So even though the ice in the middle may never melt as long as it stays 3km high, it’s a different story if for any reason that ice was reduced to a lower altitude, say 1.5km.” How could this happen without melting 1.5 km of ice? This seems to me to be a prodigious thing in itself. Also, you mention something about a temperature of 2 deg C after which the cap will begin to melt. By this, do you mean an average annual mean temp of 2 degrees in the middle of Greenland, or a summer mean temp of 2 degrees, or an increase of 2 degrees in one of these means? Would you mind clarifying your points for me?

    Incidentally, by “this ice will never melt”, I mean within this millenium. And for a long time afterward, I expect.

    Thanks;

    Comment by Ken Robinson — 12 Feb 2006 @ 4:58 PM

  220. Re #219 and #217

    Losing the first half of the ice from Greenland would be relatively slow because initially most of the ice loss has to involve glacier transportation down to the ablation zone but as the ice becomes lower the size of the ablation zone becomes larger and the rate of ice loss becomes larger. If the central plateau gets down to 1.5km then nearly the whole lot may be in the ablation zone so it would melt many times faster than it could now. So even though the first half might take hundreds of years to melt, the last half is likely to melt in a small fraction of the first half’s time.

    By 2 degrees C, I meant 2 degrees of warming from pre-existing temperatures to cause Greenland ice-cap melting. You can read what Hansen has to say in http://pubs.giss.nasa.gov/docs/2003/2003_Hansen.pdf page 30. On checking it, I notice Hansen actually says 1 degree and that others have said 2 degrees.

    Regarding the warming that has actually occured in Greenland in the last hundred years, regional effects could have the same magnitude as global average warming in the last 60 years (0.5 degrees C). As long as these are not negatively correlated to any level of global warming, it is not likely that Greenland will escape most of the future global warming which will most likely be a lot more than we’ve already had (0.8 degrees C since 1920).

    [Response: The '2 C' number being talked about is from the pre-industrial (not present-day), and Hansen is talking about a further 1 C - not too different. -gavin]

    Comment by Chris O'Neill — 12 Feb 2006 @ 8:17 PM

  221. Re #160 Dr Connolley: I’ve just realized that you commented this post of mine. When I said that “I am in no position to discuss your or Wikipedia’s assertions” what I meant was that I am obviously too ignorant to engage in a discussion with you over the issues at stake. I may dare to judge some “sceptic” scientists’ opinions reasonable but I have the utmost respect for scientists working in such complex areas as GCMs and devoting their efforts to better understand climate. Perhaps it was unnecessary from your side to reply that I was talking “nonsense”. Whatever makes a prestigious scientist misinterpret and overreact to a candid comment by a well-meaning observer?

    As for the links you requested, here is one: http://www.tcsdaily.com/article.aspx?id=042505C

    Comment by Mikel Marinelarena — 13 Feb 2006 @ 10:05 AM

  222. If I may summarize again my personal conclusions on this whole debate:

    1) CO2 is a trace gas in the atmosphere, measurable only in parts per million. However the observed 30% increase in its concentration can produce, ceteris paribus, a modest warming of the average temperature on the surface of the earth. This warming is estimated by Gavin Schmidt at almost 1 oC.

    2) According to the very Wikipedia article William pointed to, the AGW theory predicts a warming of the lower troposphere by a factor of about 1.3 over that of the surface. This has not been observed by any satellite or radiosonde, even after the correction of some detected measurement errors. The surface temperature increase of the last 3 decades itself is at the very low end of the AGW predictions, reaching about 0.187 oC/ decade. Prior to that, it was actually decreasing.

    3) Michaels (http://www.tcsdaily.com/article.aspx?id=042505C), Lindzen, Balliunas and many other climate scientists interpret that the AGW theory predicted a larger warming of BOTH polar regions than the global average, which is also not being observed on the South Pole (in spite of the constant bombardment in the media about a “melting Antarctica” as prove of AGW being real). Gavin and Eric (http://www.realclimate.org/index.php?p=18) and Cecilia Bitz (http://www.realclimate.org/index.php?p=234) contend that, in fact, the polar amplification does not apply to the SH and their models never predicted it. Gavin asserts that “we fully expect Antarctica to warm up in the future” while Cecilia Bitz does not think that we should expect to see any significant warming in Antarctica until the 2nd half of this century. I am not convinced either way here. What does the AGW theory exactly predict as regards polar amplification for the various GHG concentration scenarios? What DID it predict in the past? It shouldn’t be difficult to find out who is right on this one.

    4) Prof. Jon Jenkins expressed some interesting criticism in this thread on the AGW theory. His scepticism about how GCMs are being used (shared by many scientists inside and outside climate research) is of particular importance to me. As long as the time-honored Scientific Method is not abandoned (observation -> formulation of a theory -> quantitative predictions -> independent empiric validation), the capability of computers to manipulate data can be very useful. But computer models cannot be used to make predictions and also to validate theories. The latter would fall outside the Scientific Method. Until predictions are empirically validated anything produced by a GCM will be nothing better than predictions based on a given theory or set of theories.

    5) Many AGW adherents seem to believe in some sort of “Oil Industry -> libertarian politicians -> don’t know what -> conspiracy” and in their ability to prevent the development of cheaper ways of producing energy not only in the US, but apparently anywhere else in the world. I don’t feel that any amount of reasoning would make them change their mind. But I do hope that the amount of scientists working in climate research and sharing such views is negligible.

    Finally, the AGW theory may well be right, which we should be able to find out sooner rather than later (in another thread on this same website I see some scientists already debate on the best ways to tweak the earth’s thermostat!! http://www.realclimate.org/index.php?p=246#comment-8227) but in the meantime some sceptic opinions seem well founded. Dismissing or ridiculing them does not add much credibility to the AGW theory.

    Comment by Mikel Marinelarena — 13 Feb 2006 @ 10:09 AM

  223. Re #222 2)

    “According to the very Wikipedia article William pointed to, the AGW theory predicts a warming of the lower troposphere by a factor of about 1.3 over that of the surface.”

    Where in http://en.wikipedia.org/wiki/Satellite_temperature_measurements does it mention a factor of 1.3?

    In spite of the conclusion “This has not been observed by any satellite or radiosonde, even after the correction of some detected measurement errors”, the wikipedia page actually says “Climate models predict that the troposphere should warm faster than the surface, so all but the Spencer and Christy version of the satellite record are compatible with this and the surface records.”

    Comment by Chris O'Neill — 13 Feb 2006 @ 11:10 PM

  224. Re #221: Mikel, if you scroll through all of the comments you’ll find that “my side” corrected you multiple times on your misinterpretation of the CCSP report, but somehow the point never seemed to sink in. To respond as you have by linking to Pat Michaels, who promotes on the linked page his recent book “Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians, and the Media” is not only unpersuasive but peculiar. Part of the reason I directed you to Steve Schneider’s page on contrarians was so that you could figure out who some of those people are and not waste your (or our) time with their stuff. (Had you looked, BTW, you would have found out that Pat’s activities are funded by the coal industry.) Instead, you responded to my suggestion by tossing out an irrelevant (and incorrect) ad hom about Steve Schneider. This seemed less than constructive on your part.

    Comment by Steve Bloom — 14 Feb 2006 @ 12:41 AM

  225. Re #223 Chris: click on the graph and read below. In fact, I didn’t have a clue what the exact difference between surface and lower troposphere temperature ought to be until William provided his Wiki link and, following his suggestion, read it thoroughly. BTW, One surprising thing I noticed is that the exact radiosonde measurements are absent from that Wiki article. My link from the CCSP does include them: http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/sap1-1prd-exsumfigs.pdf. Check them and judge by yourself.

    Comment by Mikel Marinelarena — 14 Feb 2006 @ 10:29 AM

  226. Re #224: Steve: I never addressed the CCSP report so I can hardly have misinterpreted it. If you want your point to finally sink in I suggest you describe specifically how I am misinterpreting the analysis of the lower troposphere and surface measurements the CCSP publishes in the link I provided, see comment above.

    I agree that ad-hominems should rather be left out of the debate. Pat Michaels has never made any secret of his wanting to continue benefiting from the achievements that the American economic system and the technological society have brought about. He does belong to groups endorsing those agendas. Why are some people so uneasy about that? I thought that it was worth while pointing out that Schneider had previously endorsed Global Cooling because the very existence of such a recent AGC scare endorsed by the same activists and some scientists is a KEY reason to understand why many people are sceptical about AGW now. If you think that I am making false statements against Schneider please check this webpage and correct not me, but his author, William Connolley: http://www.wmconnolley.org.uk/sci/iceage/ponte.html

    Comment by Mikel Marinelarena — 14 Feb 2006 @ 10:31 AM

  227. Re #222 point 5: As I explained to you before, it does not take any sort of “conspiracy theory” in the common usage of the term to suspect that scientists have various biases and that there will be a few scientists who will particularly stubbornly stick to their beliefs for whatever reasons, thus providing fuel for libertarian think-tanks and the fossil fuel industry (who most of these scientists seem to have some close association with). This sort of thing has in fact been true time and again on other issues, whether it be depletion of the ozone layer or the dangers of smoking (and in fact, some of the same characters have even been involved)!

    What constitutes a true conspiracy theory is believing that the mainstream scientific consensus as reflected by the IPCC, National Academy of Sciences (of the U.S. and similar bodies in many other countries), the councils of the AGU and the APS, etc. can all be hijacked by a political agenda, as many deniers of global warming suggest.

    This is why it is important in climate change, or any other issue, to listen mainly to what is being said by the peer-reviewed scientific community as a whole and not simply to cherry-pick the viewpoints of a few scientists who hold the viewpoint that one happens to favor. Doing this is a recipe for disastrous policymaking, as the current U.S. administration amply demonstrates.

    Comment by Joel Shore — 14 Feb 2006 @ 3:23 PM

  228. Re #226 (MM): The CCSP report describes the entire history of the various data sets. That is *not* the same thing as saying they are all valid. As noted, the authors state that any remaining discrepancies are far more likely to be remaining errors in the data than in the model predictions, which is a polite way of saying that S+C’s stuff is likely still somewhat wrong (and noting that Christie himself signed on to that statement). Let me know if there’s anything else that’s unclear about this.

    The Schneider quote you refer to does not endorse global cooling. Rather, he endorses the idea that the public should be educated about the potential for substantial instability in the climate. The scientific basis for the claims in the book are somewhat spurious, much more so in retrospect, and William’s comment is essentially that it’s too bad that Schneider’s quote could be *misinterpreted* to endorse the specific claims made by the book. The full quote is:

    “The dramatic importance of climate changes to the worlds future has been dangerously underestimated by many, often because we have been lulled by modern technology into thinking we have conquered nature. But this well-written book points out in clear language that the climatic threat could be as awesome as any we might face, and that massive world-wide actions to hedge against that threat deserve immediate consideration. At a minimum, public awareness of the possibilities must commence, and Lowell Ponte’s provocative work is a good place to start.”

    Comment by Steve Bloom — 14 Feb 2006 @ 3:31 PM

  229. And remember to suspect hidden funding. Decades went by before journals reported on how science was being manipulated by the tobacco industry. Money corrupts.

    http://www.ajph.org/cgi/content/abstract/96/1/20
    http://tc.bmjjournals.com/cgi/content/full/14/4/217
    http://tobacco.health.usyd.edu.au/site/supersite/contact/pdfs/jech_drope.pdf

    Comment by Hank Roberts — 14 Feb 2006 @ 3:40 PM

  230. As it turns out, if you click on the History tab of the Wikipedia article William sent us to: http://en.wikipedia.org/wiki/Satellite_temperature_measurements the leading contributor, if not the author, is himself! He’s actually one of Wikipedia’s administrators, having authored pretty much everything having to do with climate change on that website. I really think that he should have clarified this when he mentioned that article. I’m not very impressed.

    [Response: Nor am I: you have nothing at all to say on the content, just reporting the easily-observed fact that I wrote some of it. Come back when you can find something actually wrong with it - William]

    Re #228 Steve, we’re talking semantics here (again,…) Alright then, let’s put that Schneider’s endorsement of Ponte’s infamous book was not a specially ringing one. Everybody happy now?

    As for the CCSP link I provided http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/sap1-1prd-exsumfigs.pdf I see that you continue refusing to address it and refer me again to the CCSP summary. You have 8 comparisons between surface and lower troposphere temperatures and all of them but one show a smaller warming of the troposphere than the surface. How do you personally reconcile this with the summary you once and again cite?

    All of this ties in with two of Lindzen’s criticisms of the IPCC. A) Its summaries don’t summarize very well the real consensus among scientists and B) when data are found that do not validate predictions the immediate reaction is to try and correct those data, rather than correcting the theories they challenge. Shouldn’t we all feel very happy if eventually we found out that the world is not really going to warm as we so much feared???

    [Response:A) is nonsense. B) If you're talking about the satellite record again, you need to stop scratching this itch, and face the obvious: that those suspicious of the satellite record from S+C turned out to be right; and the S+C data wrong - William]

    Comment by Mikel Marinelarena — 16 Feb 2006 @ 2:22 PM

  231. [Response: Nor am I: you have nothing at all to say on the content, just reporting the easily-observed fact that I wrote some of it. Come back when you can find something actually wrong with it - William]

    [Response:A) is nonsense. B) If you're talking about the satellite record again, you need to stop scratching this itch, and face the obvious: that those suspicious of the satellite record from S+C turned out to be right; and the S+C data wrong - William]

    Dr Connolley,

    Nothing further away from my intentions than engaging in one of those never-ending rows I have found you get entangled in at Wikipedia, where a certain amount of verbal abuse also seems to be present.

    So I will not come back if I’m not welcome on this website but just for the record, in my search to find out whether there is any substance in the sceptic scientists’ contentions, I have pointed out 2 concrete issues on your Wikipedia article: 1) Even after correcting S+C’s measurements, the 1.3 larger warming of the lower troposphere is not validated by available MSU data. 2) Radiosonde measurements are absent from that article. I have found a CCSP webpage where they are accounted for and the discrepancy is even more obvious: the troposphere warming is actually lower, not greater.

    Hard though I’ve tried, I haven’t managed to get any explanation for these apparent inconsistencies. I’ve only been referred once and again to the expert’s summaries or to C+S’s admittance of their having committed some errors, which does nothing but reinforce my suspicion that Lindzen might be right in his above-mentioned criticisms.

    Unlike you, I have no itches to scratch. Whatever happens to the AGW theory, I will continue to be a happy man. Only I’d really hate to see the natural landscapes I so much love change abruptly by AGW, hence my interest in the subject. Speaking of which, you are welcome to come back to the Pyrennees when you so please. We are enjoying one of the best ski seasons ever, due to the unusually cold winter.

    [Response: S+C are not the only analysis of the MSU data. RSS and Vinnikov et al (2006) have alternate analyses of the same raw data, both of which give significantly more warming in the tropopshere than S+C. Thus there is uncertainty in the satellite results. Over the 25 years of the record, climate models show significant variability in tropical tropospheric temperatures - the mean ratio over all models and all ensemble members is indeed 1.3, but the value in any particular realisation (of which the real world is just one of course) varies (as you have seen in the CCSP figures). The range of ratios in the models and the range of estimates from the different satellite analyses overlap - which implies there is no longer an inconsistency between them. Prior to the last set of corrections to S+C, there was. There is no longer. Please read the two posts on the subject from last year (here and here), and better still read the Santer et al (2005) and Sherwood et al (2005) papers in Science for more information. -gavin]

    [Response:1) Gavin has done this 2) did you read past the first para? - William]

    Comment by Mikel Marinelarena — 17 Feb 2006 @ 9:27 AM

  232. Re #231: Since William didn’t say it explicitly, note that the 2nd of the two RC articles that he linked to deals with the issue of the radiosonde measurements.

    Also, I have to admit that I am a bit skeptical about your claim of having “no itches to scratch” by which I presume you mean no biases. I think your posts have made it quite clear (to me at any rate) that your views on economics issues mean that you have strong feelings about policies like the Kyoto Protocol and, therefore, that you might have strong feelings in regards to the science that provides the evidence that we have to seriously reduce our greenhouse gas emissions. I am not denigrating you for having such a bias but I think it may be a bit disingenious to claim to have none.

    Comment by Joel Shore — 17 Feb 2006 @ 2:26 PM

  233. That’s alright Gavin. But following your rationale, the wider the range of ratios in the model outputs, i.e. the more inconsistent they are with each other (or the larger the discrepancies between different observation analyses) the more overlapping there will be and thus both will be “compatible”. One can even envisage one situation where, as long as the average of the former shows AGW, the AGW theory/ies can remain unchecked, pretty much regardless of what actual observations show. I’d rather see models showing consistent predictions and these being validated by the best available historic data. In the meantime, you should tolerate some scepticism. You see, some of us remember the global cooling scare (among so many others) or the NASA “long term weather predictions”.

    Re#232 Being an economist, I can’t help having my views on certain economic issues, can I? However, I very much doubt you value a naturally stable climate more than I do. The problem I see, as an economist, is that, regardless of my personal priorities, people like my children or the less disadvantaged will also have to pay for the pricey climate insurance policy that is being implemented.

    Comment by Mikel Marinelarena — 18 Feb 2006 @ 2:33 PM

  234. There was no “global cooling scare” coming from the scientific community that even remotely resembles the warnings and consenus that exist now about AGW. I’m sure you are familiar with all the links that demonstrate this. Here are a couple again:
    http://www.realclimate.org/index.php?p=94
    http://www.wmconnolley.org.uk/sci/iceage/

    Do tell what you have in mind when you slip in “(among others)” given that the one concrete example you have is bogus.

    Comment by Coby — 18 Feb 2006 @ 3:37 PM

  235. Are there any climate models that give results consistent with what the current ‘skeptics’ say are the facts?

    Is there a model somewhere that shows this global cooling risk as a real thing and includes assumptions about things so it comes out that the global temperature will stay approximately the same if we burn all the carbon at the present rate, by offsetting some other force?

    It seems odd that there’s no Coal Industry Climate Model, or something along those lines. I’d think they’d have one or several to show.

    Comment by Hank Roberts — 19 Feb 2006 @ 12:14 AM

  236. #216 Ferdinand, I gather you may add that the “edges” of the Greenland ice sheet not only melts in the summer but gathers a certain temprature by being immersed during the long night air having certain temperatures. Lets say that the dark season average temperature sutrrounding Greenland at 1000 meters has increased by 10 C, (a practical number now a days), that would mean 2 things: 1- summer warm air contact conduction would require less heat to gather a further melt, and 2, the very chemistry of high pressure ice probably changes in the long run if its core temperature is warmer. So, this saying that top of the ice sheet average summer temperature of -14.5 C misses the mark, and does not explain the real causation of Greenland’s greater ice shedding.

    Through my experience with optical effects, mirages, on top of hills or mountains having differing temperatures with the air, I can literally see such dynamics. For instance a hill immersed in -40 C weather for 3 weeks, creates a great show
    of mirages when warmer air envelopes it, creating illusions, not so known like horizon lines, where a complete horizon beyond the other side of the hill from the observer is minituarized in a fine line less than 1′ of arc thickness. What this mirage means is that the hill is significantly colder than the air, and retains such temperatures properties for significant periods of time. Conduction is a very significant process with Greenlland ice likewise, and warmer air, still well below zero degrees C, plays a significant role. Even exacerbated by recent shortage of multi year ice of the Arctic ocean, there is perhaps a greater feedback effect caused by warmer air than previously thought, and the difficult focus. research, over great ice sheet dynamics must be accelerated.

    Comment by wayne davidson — 19 Feb 2006 @ 4:56 AM

  237. Another factor I wonder about: I think I have read that the temperature at the bottom of the Antarctic ice is only a few degrees below zero due to geothermal heat and an insulating effect of the ice between the much colder surface air and the ground. How much does the surface need to warm before the geothermal heat will melt the ice from the bottom (if at all possible)?

    I don’t know if the situation is the same in Greenland, though I don’t know why it shouldn’t be…(thinner ice?)

    Comment by Coby — 19 Feb 2006 @ 1:22 PM

  238. #237, Coby good point, rather all the above, there are some ice walls 100′s of meters high, always soaking what heat made available, its becoming clearer how North Americas massive 2 mile high pan continental ice sheet disappeared during the last glaciation period.

    Comment by wayne davidson — 19 Feb 2006 @ 8:51 PM

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