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  1. Thanks, Gavin, for clarifying this. I saw this at New Scientist (with plenty of comments) and was wondering what it meant.

    Comment by catman306 — 4 Jan 2008 @ 8:44 AM

  2. Typo catch(?): “when surface temperatures near the surface”…as opposed to surface temperatures where?

    [Response: thanks – gavin]

    Comment by Adam — 4 Jan 2008 @ 8:45 AM

  3. This is a ridiculous post. After reading the paper I did not get the impression at all that the authors wanted to suggest that climate models are misleading. I wouldn’t be surprised that a reviewer insisted on this paragraph in the conclusions, while the authors didn’t want to mention this at all.

    It is bad enough, that nowadays you cannot publish in Nature anymore without having to add these kind of paragraphs. Your weblog is not helping science by writing articles like this, but is creating an atmosphere in which scientists constantly have to excuse themselves if they want to publish anything that might not fully match the IPCC conclusions.

    [Response: Huh? All I’m asking for is that statements be backed up. If the models really don’t match, then that’s interesting too. But careless throwaway lines like this lead to plenty of misleading press and I’m not the only one who noticed (see Climate Feedback for instance). – gavin]

    Comment by PJGrefhorst — 4 Jan 2008 @ 9:00 AM

  4. How is it that this wasn’t picked up during peer review? It would seem that inclusion of some analysis of the current models results would improve the paper which is the purpose of peer review.

    Comment by Keith Whelpdale — 4 Jan 2008 @ 9:10 AM

  5. PJGrefhorst, did you bother actually reading what Gavin wrote? For one thing, we’re talking about the models here, not IPCC conclusions. And what Gavin is saying is that there isn’t a mismatch. Do you have any basis for your speculation that the authors were “forced” to include said paragraph? Methinks you ought to go back and read the comment a bit more thoroughly.

    I was also struck by the press accounts here. They didn’t seem to have any understanding that athropogenic greenhouse forcing is only one of several factors at work in climate. It’s just that anthropogenic greenhouse forcing will be operative for several hundred to several thousand years, and so will have a very serious effect on climate. The fact that there could be other fluctuations or variability does not alter this conclusion.

    As William James said: “A difference which makes no difference is no difference at all.”

    Comment by Ray Ladbury — 4 Jan 2008 @ 9:26 AM

  6. When I read this I immediately thought of Dian J. Seidel’s paper wherein the “the structure and circulation of the atmosphere…[causes an]…expansion of the tropical region toward the poles”.

    Could this process be behind the “atmospheric heat transport” mentioned above? Or no?

    Because the Seidal result is thought to be AGW related, so could there might be
    causality at one remove.

    Comment by bigcitylib — 4 Jan 2008 @ 9:36 AM

  7. This is an interesting paper. The line you note seems to be a balancing act.”Our results do not imply that studies based on models….are misleading” allows the authors to say they are not calling the models out of line, but the the whole section implies that the models are. Have your cake and eat it too. Their science would be stronger if they looked at the model results and used this to correlate and contrast and put their work in perspective. But their paper is of more newsworthy nature with the small section added. Is this section inclusion then driven by science? One question? Why would the snow and ice feedback from the surface not be powerful enough to matter to air temps at 2 km even in summer, just due to the reduced importance of long wave radiation emission in the overall heat budget?

    Comment by Mauri Pelto — 4 Jan 2008 @ 9:54 AM

  8. Hi Ray,

    I don’t have any basis for this speculation, but if you read the article it seems to come out of the blue. Maybe RealClimate can ask the authors to comment on this paragraph.


    Comment by PJGrefhorst — 4 Jan 2008 @ 9:57 AM

  9. Another relevant issue regarding this paper is that that their study, based on data from the ERA-40 reanalysis, ends in 2001. A lot has happened since then. If one looks at latitude by height cross section of temperatures from the NCEP/NCAR reanalysis, expressing 2001-2007 as anomalies with respect to 1979-2007, there is a very clear signal of stronger warming at the surface over the Arctic Ocean during autumn. This appears to be quite consistent with the strong losses of summer sea ice since about 2001, leading to large heat fluxes to the atmosphere in autumn. The signal is there even when eliminating 2007, when late summer ice extent was at a record low. Put differently, the analysis in the Graverson et al paper ends at just about the time when the real “action” begins.

    Comment by Mark C. Serreze — 4 Jan 2008 @ 9:58 AM

  10. From the paper:

    “Our results do not imply that studies based on models forced by anticipated future CO2 levels are misleading”

    From the post:

    “it should be standard practice to at least give a cursory look at what models actually show before accusing them of being misleading.”

    They don’t accuse any models of being misleading.

    Comment by Fair weather cyclist — 4 Jan 2008 @ 10:01 AM

  11. “Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming…Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, …We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.”
    They clearly imply that climate models do not take into account “atmospheric heat transport”

    Comment by kyangadac — 4 Jan 2008 @ 10:16 AM

  12. No, they don’t accuse any models of being misleading. When they write

    Much of the present warming, however, appears to be linked to other processes, such as atmospheric energy transports.

    When linked with the sentence you’ve posted, as it is in the paper and in the original post, it certainly appears they imply that the models ignore possible changes atmospheric energy transports. Which is what the original post is complaining about.

    Or do you read that sentence in another way? If so, perhaps you can share your understanding of what they mean?

    Comment by dhogaza — 4 Jan 2008 @ 10:25 AM

  13. I was actually asked about the paper coming out by the AP reporter (Seth Borenstein) and sent in the following comments. I was not, however, quoted in the article (my explanation was perhaps a bit technical, but done to refute the rather strange conclusion being discussed) and the perspective in the AP article ended up not in accord with my comment. I put it here as it might be of interest.

    Mike MacCracken

    Hi Seth—Well, an interesting paper, to which one might say of course to their point that changes in transport have been playing a role, but I think they jumped the gun a bit by suggesting that it appears that the snow and ice albedo feedbacks were not significant factors in contributing to the response. I say this because it appears to me that they left out consideration of infrared radiation as a process that could connect changes at the surface and with changes in the layer aloft. For example, if transport brings in more water vapor, then the IR flux to the moistened layer will increase and cause warming, especially if albedo feedback provides more warming at the surface; it is just not obvious that the change in albedo near the surface has to cause the largest influence near the surface—radiation can carry energy changes to higher layers. [And, indeed, as they cite from reference 12, one will get some amplification even without albedo feedback, likely because at high latitudes the GHG effect is responded to mainly by temperature change since water vapor is so low (per Clasius-Clapeyron relationship), whereas in lower latitudes a larger fraction of the GHG-trapped energy must go into evaporation—so there is sort of a Bowen ratio effect.]

    Quite clearly from Figure 1(d), in the autumn the whole layer can be affected by what has happened at the surface (they sort of indicate this was by transport, but it could as well be by changes in radiation terms). That the albedo effect itself is strongest in summer in terms of energy fluxes is true, but the energy accumulated over the summer in the ocean due to a lower surface albedo has its greatest impact on air temperatures in the fall when the heat is returned to the atmosphere due to the absence or thinness of the sea ice—so delays are expected.

    This is not at all to say that their suggestion that circulation changes make a difference is incorrect—of course that should be expected as well, for the atmosphere will respond to changes in energy sources and sinks by carrying energy and water vapor around. Their calculation of energy transport seems to include latent heat (see Methods section), but their figures focus on showing the changes in the temperature field (instead of equivalent potential temperature—which would account for the latent heat term, and the vertical movement term as well, which could be affected by changes in the large scale overturning circulation). They did not seem to compare their analytic results to those of models including all the various terms to see if there are differences (e.g., relating to an incorrect representation of albedo feedbacks); what the models do is keep track of everything quantiatively, so they overcome some of the special focus of this paper’s analysis.

    Basically, I’d say, this is a fine analysis as far as it goes, but I don’t think one can evaluate the relative role of surface albedo impacts in this way, especially as everything is interconnected. An energy change in one place, for example near the surface, will trigger changes in circulation, etc., so is the circulation change related to the albedo effect—just not clear from this analysis. So, I don’t think this paper will in any way upset scientific understanding—though it is certainly possible some of The Skeptics will claim something.

    Best, Mike

    [Response: Thanks Mike, this is very englightening. Seth Borenstein is generally a very good, careful journalist, but nobody is perfect, especially when the subject matter deals with some rather technical issues. Its seems there is a lesson here for us. Namely, that tempting as it may be to get into technical nuances, we need to provide as concise and non-technical an explanation of these things as we can when the material is intended for popular consumption. – mike]

    Comment by Mike MacCracken — 4 Jan 2008 @ 11:23 AM

  14. Re # 3 :
    “Your weblog is not helping science by writing articles like this, but is creating an atmosphere in which scientists constantly have to excuse themselves if they want to publish anything that might not fully match the IPCC conclusions.”

    I think that what’s helping science even less is to start from the premise that everything in the IPCC report is evil, and to constantly ask climate scientists to find issues with it. I see a lot of this now on the blogosphere and it is quite annoying. This example suggests that it now begins to infuse the literature as well.

    While healthy skepticism is the basis of scientific methodology, there are people for whom IPCC-trashing has become the new orthodoxy. Personally, i think Gavin is right in pointing out when such excesses outcrop in the literature without any form of backup.

    Especially when it takes 10 minutes to verify that the devilish GCMs actually don’t do what they are accused of…

    [Response: Well put Julien. Thanks for stopping by – mike]

    Comment by JEG — 4 Jan 2008 @ 11:25 AM

  15. So, how do we train editors to call someone like the RC folks before they republish the rubbish? If an editor at AFP ( ) had called Gavin, the poorly phrased material would not have been republished in many local newspapers.

    I am coming to think that newspapers in the US pander to what they think their readers already believe, and do not try to educate and correct misconceptions held by the public. I cite as exhibit 1 the NYT New Year’s day piece “In 2008, a 100 Percent Chance of Alarm “ by John Tierney. (

    All I can say is no wonder Tierney had a hard time getting papers published in peer reviewed journals.

    Comment by Aaron Lewis — 4 Jan 2008 @ 12:13 PM

  16. Are you saying that the models predict very little warming at the surface at high latitudes (Arctic)?

    All the zonal projections I have seen (including those in the IPCC reports) show the largest surface temperature increases will occur in the high Arctic.

    This is clearly outlined on Page 15 of the Summary for Policy Makers – Working Group 1 of IPCC AR4.

    [Response: The warming is very clear in the annual or winter time means – the summer was the point of contention here. Check out the GISS model results (as indicated above) for different seasons and you’ll see. – gavin]

    Comment by John Wegner — 4 Jan 2008 @ 1:39 PM

  17. In #15, Aaron Lewis writes:

    “All I can say is no wonder Tierney had a hard time getting papers published in peer reviewed journals.”

    Tierney is one of the two NYT token conservative op-ed columnists. His op-eds are uniformly silly, even by the relaxed standards of token NYT conservative op-ed columnists. He is not a scientist, although he does occasionally play one in the NYT editorial pages.

    Best regards.

    Comment by Jim Dukelow — 4 Jan 2008 @ 2:00 PM

  18. Aaron, Tierney is a columnist, a ‘bertarian spin writer.

    How do you come by your belief that “Tierney had a hard time getting papers published in peer reviewed journals” and why do you trust whoever told you that?

    He’s not a scientist. He doesn’t do peer reviewed work.

    Comment by Hank Roberts — 4 Jan 2008 @ 2:49 PM

  19. It looks to me, as one that’s made a minor hobby of watching the jet-stream and the weather pattern shifts from satellite over more than years, that there is a tendency for a new or at least a stronger Hadley cell system over the newly exposed Arctic ocean. This tendency persists up until the ice solidly freezes over in November.
    This would be the effect, I assume, seen by the Nature paper, and should also appear in any good model.
    The new Hadley cells I see are pretty intense if they can be seen by eye. They also seems to transport major quantities of heat, as the whole Arctic heats up when one occurs. The one that’s easiest to see is the one that forms around the Bering Straight.

    Comment by ken rushton — 4 Jan 2008 @ 2:50 PM

  20. New Rule: Publish a “high profile” paper of your own instead of enlisting the drones of Climate Change to comment. Gavin, if you have a problem with this paper then publish a rebuttal and submit it, increasingly this site has become you and your colleagues soapbox for non-relevant musings regarding the work of others. I do not worry about quotes in mainstream media and single lines taken out of context from published works. Perhaps the op-ed attitude of James Hansen has permiated your culture so far that you feel that this is your personal mission, who knows, but lets have more of the science (and less critiques on grammer or perceived slieghts against your work).

    Next what about the actual subject and conclusions of the paper itself? Any useful comments?

    [Response: My publication record speaks for itself. But frankly, you complete misunderstand the purpose of my post. There is no issue with this paper that would merit a comment to Nature, let alone having Nature actually publish it. This is simply a comment about loose language and the ensuing press confusion. Presumably you’re not in favour of that? This has nothing to do with any faults of grammar or comments on my work (I didn’t see any). If you don’t like my musings, you don’t have to read them. – gavin]

    Comment by Daryl — 4 Jan 2008 @ 3:30 PM

  21. Gavin:
    Going in search of monsters seems a symptom of the disease this site is supposed to cure. Oliver Morton is well placed to fisk both Nature and the press coverage , and his Climate Feedback post concludes :

    “So I’m a little surprised that the paper is being seen as evidence that the human role has been exagerrated. ”

    This is not to deny they are out there-

    But merely to observe that Graversen et al. are under no obligation to base their emphasis, or lack of it, on other people’s enthusiasms.

    [Response: Of course not. It just happens to be a pet peeve of mine that statements like ‘models show’ this or that often occur without any reference to what models actually show and under what circumstances. At times, this has consequences beyond the few scientists that read that far down in the paper. – gavin]

    Comment by Russell Seitz — 4 Jan 2008 @ 3:40 PM

  22. RE #20 & “publish a rebuttal”

    The problem is everyone swarms over the original article and it gets publicized, and corrections and rebuttals are often ignored, at least by the mainstream media and media consumers. With the possibility of dangerous outcomes from GW, respected journals should be extra-cautious in publishing misleading info that might detract from mitigation efforts.

    A mistake on the other side, such as overestimating the danger from GW, would not be harmful, since as we all know mitigating GW (even if it is not happening…and it is) would be of great help in saving people money and boosting the economy, without lowering living standards or productivity. Sort of a win-win-win-win situation, when you factor in better health and wealth and well-being from reducing other enviro problems to boot.

    It’s better to err on the side of caution than danger.

    Comment by Lynn Vincentnathan — 4 Jan 2008 @ 4:25 PM

  23. Careful wording in papers is important in the current environment.

    The environmental news network sends out a daily e-mail with summaries of news reports about environmental politics and science mostly from Associated Press and Reuters. News reports about recent climate science papers come out every other day. From this week alone:
    “2008 to be in top ten warmest years”
    “First-ever study to link increased mortality specifically to carbon dioxide emissions”
    “Trees are not the answer to global warming”
    Any poorly worded papers will spread fast and far.

    The scientific papers are read in the contrarian circles with an eye to spot poorly worded parts and then use these parts to sow doubt. Even the most inadvertent misstatement will be talked up on the contrarian websites.

    I would go as far as recommend getting a lawyer to parse the language before releasing the paper.

    #18 (Hank Roberts), #17 (Jim Dukelow) et al the NRDC’s blog has an interesting post about the Tierney piece

    Comment by Joseph O'Sullivan — 4 Jan 2008 @ 4:40 PM

  24. New Rule: Publish a “high profile” paper of your own instead of enlisting the drones of Climate Change to comment. Gavin, if you have a problem with this paper then publish a rebuttal and submit it.

    I don’t think that we need any “new rule” restricting scientists to only expressing their opinions in the pages of peer-reviewed publications (which generally have very limited space for comments, anyway). Frankly, this sounds like a rhetorical stratagem to try to muzzle opinions that you don’t like. Go to a scientific meeting or a seminar at a university sometime–you will see scientists standing up and expressing critical opinions quite freely, without submitting them first to peer review. Scientists certainly appreciate the value of peer-review, but it a mechanism for quality control, not censorship of scientific discourse.

    Comment by trrll — 4 Jan 2008 @ 4:48 PM

  25. Re 19. Tierney claims to be a science writer and this article was in the Tuesday Science Times section. It is a fluff piece that reflects the intellectual laziness found in most of his writing, and about which he actually boasts in his NY Times personal page. Unfortunately, appearing in the Science Times, it will be taken seriously by many of the uninitiated. It is a mystery to me why the Times continues to sully its reputation with a guy like this.

    Comment by Ron Taylor — 4 Jan 2008 @ 4:55 PM

  26. There is one problem, I believe, worth addressing on RC when responding to articles. In order to avoid projecting one’s own biases or negativities I suggest that we reflect more carefully on what we are reading so as not to see what is not there. The old story is that we see what we want to see and this can also be true in response to scientific articles. I’m not a scientist but I do teach courses dealing with mis-perception. Though RC obviously strives to be unbiased it is still subject to the use of words, and words have their own emotional content. Everyone within e-mail range tends to have a hurry-up mindset because of the immediacy of e-mail, which means that emotions and feelings are engaged in rapidly. This hurry up mindset makes us respond quickly and often far more emotionally than intended, resulting in unintended consequences. My recommendation, for what it is worth is to read over at least three times, and with care, any article that you are responding to, taking into consideration our very human tendency to mis-perceive.

    Comment by Hugh Curran — 4 Jan 2008 @ 5:29 PM

  27. Re #20. This site has been and continues to be in large part a very good site for the attribution of global climate change. I find, as one of the “drones” that whether you’re an protagonist or skeptic, you have to agree that the standards of the contributors demand technical accuracy above all. As one of the protaganists, there have a few occasions when I’ve let feelings get in the way of facts and have had posts that were unable to make the cut.

    As far as Post #3. Any one who does meticulous, carefully objective science has nothing to fear from this site. Papers both pro and con have been reviewed in RC and the detailed discussions that follow lead to a better understanding of the issues.

    Comment by Lawrence Brown — 4 Jan 2008 @ 7:42 PM

  28. Gavin:

    Did you look at data from any of the other models in the archive? I took a quick look at ensemble averages from the GFDL CM2.1 and NCAR PCM 20th century runs and neither of those models do a good job of reproducing the vertical structure for JJA as shown in Fig. 1 of the paper.

    Perhaps there is some basis for the statement that caused all the fuss, although it certainly would have been more convincing if there was some indication that the authors had looked at the model data.

    [Response: No. But if you make a figure of the summer-time (JJA), 1979-2001 trends – either ensemble means or individual runs, I post them along with the GISS results as an update. If anyone else wants to pile in, I’ll post up any similar analyses as well. Maybe if you sent me the North Pole vertical profile trend data, I could actually plot it all up consistently. – gavin]

    Comment by Joe — 4 Jan 2008 @ 8:26 PM

  29. There is a good discussion of this issue also at Andrew Revkin’s New York Times blog called Dot Earth, and he links to Tierney’s original newspaper column and blog post. It makes for interesting reading, and the comments are coming in fullspeed ahead. It’s titled: “Alarming Weather and Global Warming” and the link is here:

    Money quote: “And, as I blogged recently, the media definitely have a tendency to get seduced by the “front page thought” when dealing with questions about climate and, say, hurricanes, and thus can miss the legitimate questions still surrounding the science that explores links of that sort.
    John and I often disagree, and we definitely have different roles in the media landscape. But on this overarching theme there’s synchrony.” (Revkin)

    Comment by Danny Bloom — 4 Jan 2008 @ 8:37 PM

  30. “Any one who does meticulous, carefully objective science has nothing to fear from this site. Papers both pro and con have been reviewed in RC and the detailed discussions that follow lead to a better understanding of the issues.”
    Very well said. Science may begin with basic observations but it doesn’t end with peer review. If all the scientists were a bunch of super loyal frineds (read clique) then it wouldn’t be reproducible or honest. Science is not a battle of opinions. There are always multiple working hypotheses about any question in nature and most scientists tend to favor one or two particular hypotheses. But all hypotheses are subject to testing and retesting. That is the scienific method. So what’s wrong with critiquing people’s papers? Why shouldn’t RC be a forum where such a thing is done? Peer review is not the end all means to truth. Most scientists appreciate feedback, even when it is hard to hear. And it has been my experience that most people who publish in nature are pretty open to criticism. This is how science evolves. A good scientist doesn’t take offense at posts such as this one on RC.

    Comment by Figen Mekik — 4 Jan 2008 @ 9:17 PM

  31. (13) I liked your response, as it helps me understand the science better. I suspect that for >98% of journalists and the public, it would be interpreted as “it’s greek to me”. A translation (perhaps in the form of an executive summary) might look somewhat like:
    Nature couples the surface, atmosphere, and GHG effects together. Any good model will take this interplay into effect. The single quoted sentence seems out of place with the rest of the paper.

    I think we have to make it as easy as possible for journalists, and interested members of the public to gain at least an intuitive feeling for the systems we discuss. Otherwise, perhaps out of frustration at being able to do any better, they may resort to the gotcha game that we see so much in politics (and climate Change denial).

    Comment by Thomas — 4 Jan 2008 @ 9:18 PM

  32. When I read a paper that has had nothing to do with a subject throughout and then brings up a hot-button issue in the conclusion, I find myself looking for some sort of quantitative analysis that supports what they’ve said. If I do not find that, I start to wonder about motivations. This is supposed to be science after all. If you aren’t going to provide quantitative support for a statement, why make it?

    Comment by Ray Ladbury — 4 Jan 2008 @ 9:59 PM

  33. Unfortunately we don’t have the journal Nature here in the High Arctic, the introduction implies already well known heat transport mechanisms, such as more cyclones heading polewards, which was first introduced by models including AGHG’s. It is very much so, but not necessarily the only factor maintaining a warm Upper Thermal layer, now observed for many recent years by means of observing an increase in twilight brightness (during the long night, complementing the shorter perimeter radiosonde measurements ( scroll down for URL Y-V Ulluq Q Phenomena (March 22 2005) ) . I don’t know if the article deals extensively with moisture, which is becoming more and more important, particularly with strange phenomenon which I have not written about yet, of weak stars disappearing during the clear long night (having magnitudes greater than 4.2), all while having greater horizontal visibilities. Equally more common, moisture in the stratosphere. an indication of convection beyond tropopauses having weaker inversions. All an all, this article implies the correct reality, but is forgetful about past models projecting more advection by an increase in poleward cycclonic activity.

    Comment by wayne davidson — 4 Jan 2008 @ 11:06 PM

  34. What is the structure of the circulation changes involved here? (So far I know that in response to global warming, storm tracks are supposed to shift poleward (would that mean greater north-south exchange at the highest latitudes, or would expected storm/wave activity changes negate that effect?), the Hadley cell is supposed to expand, the NAM index may increase.) (I looked at the figures and abstract of the paper but don’t have access to the full text right now. I’m not sure I understood what figure 3 was showing – I mean, time lag with respect to what? – were they looking at a number of events and computing the average of all events with time lags with respect to some aspect of the type of event?)

    Comment by Patrick 027 — 4 Jan 2008 @ 11:25 PM

  35. Lynn Vincentnathan (#22) wrote:

    The problem is everyone swarms over the original article and it gets publicized, and corrections and rebuttals are often ignored, at least by the mainstream media and media consumers. With the possibility of dangerous outcomes from GW, respected journals should be extra-cautious in publishing misleading info that might detract from mitigation efforts.

    I believe you are right that journals should be more cautious and try to avoid publishing misleading information, particularly when it comes to climate change.

    Lynn Vincentnathan (#22) wrote:

    A mistake on the other side, such as overestimating the danger from GW, would not be harmful, since as we all know mitigating GW (even if it is not happening…and it is) would be of great help in saving people money and boosting the economy, without lowering living standards or productivity. Sort of a win-win-win-win situation, when you factor in better health and wealth and well-being from reducing other enviro problems to boot.

    It is potentially harmful in that it provides skeptics and their audiences with justification for claiming that there exists a bias against their views and that nonobjective standards are given free-reign in climatology. No doubt they will make such claims regardless of whether they are true or not, but your principle and enunciation of it would mean that they actually have some justification for such claims. And this may persuade those who might otherwise be open to the science — but are at present uninformed. Likewise, to the extent that we might embrace such a principle, where errors are given a free ticket if done for the “right reason,” we would corrupt our ability to see things for what they are and respond accordingly. Identification must precede evaluation, always.

    Lynn Vincentnathan (#22) wrote:

    It’s better to err on the side of caution than danger.

    Granted, but when one does so, it must be clearly demarcated as an application of the cautionary principle, not simply as an unacknowledged attempt to warp the evidence towards conclusions that they do not in fact support in the way in which the author claims.

    Comment by Timothy Chase — 4 Jan 2008 @ 11:58 PM

  36. My understanding of the expectation of global warming is, of the zonally averaged latitude-height warming distribution, that the greatest warming would generally extend from the lower troposphere in the Arctic upward and equatorward to the tropical mid to upper troposphere; with the Arctic warming being greatest in Fall/Winter. From fig 1 – although the tropics are excluded – it is interesting to note that within the midlatitudes (30 to 60 deg), the meridional thermal gradient is enhanced at most levels in winter (with the opposite in the edge of the polar region). From that, I would guess the storm track position trend in winter is opposite that of the annual trend – and also, that in winter in the midlatitudes, both frequency and intensity of storms would increase (whereas the frequency of extratropical storms would decrease in the global annual average). Is that true?

    Comment by Patrick 027 — 5 Jan 2008 @ 12:15 AM

  37. Thanks for telling me about and those other web pages. The abstract of seems to be saying that we will not go extinct by the year 2100, but that we could be in trouble. From the anthropologists I get the idea that it doesn’t take That much of a problem for civilization to collapse or change in some really bad way. The whole 6 megabyte pdf is too long to get downloaded and read right now since it won’t fit on one microdisc.

    Comment by Edward Greisch — 5 Jan 2008 @ 12:43 AM

  38. Gavin said:
    “There is no issue with this paper that would merit a comment to Nature, let alone having Nature actually publish it. This is simply a comment about loose language and the ensuing press confusion.”

    I disagree that the paper is not worth a brief letter to Nature by you or someone else. Assuming the results of the GISS archive are borne out by other models, it is worth pointing out that GCMs predict, “A significant proportion of the observed temperature amplification…[is]…explained by mechanisms that induce warming above the lowermost part of the atmosphere.” [from their abstract]

    And that models also project that, “…further substantial reduction of the summer ice-cover would strengthen these [snow and ice] feedbacks and they could become the dominant mechanism underlying a future Arctic temperature amplification.” Which appears to be borne out by recent data, if I understand Mark Serreze’s comment @9.

    Not much can be done about the popular press getting the facts wrong, but Graverson et al (and presumably many other scientists) are probably not modellers and may be operating under the assumption that GCMs don’t capture this behaviour.

    [Response: I think such a study would make an interesting paper, and the mechanisms of polar amplification even in the models have not been fully explored as yet (though a number of people are working on this). But the comment/reply route is not the place for follow-on work, rather it is supposed to address fundamental issues in a paper that might affect the conclusion – that doesn’t apply here. -gavin]

    Comment by Bruce Tabor — 5 Jan 2008 @ 1:41 AM

  39. In the abstract for the following paper, a variety of elements thought to play a role in polar amplification as analyzed by climate modeling are mentioned — and the albedo effect is nowhere to be found:

    The Arctic is among the regions where climate is changing most rapidly today. Climate change is amplified by a variety of positive feedbacks, many of which are linked with changes in water vapor, cloud cover, and other cloud properties. We use a global climate model to examine several of these feedbacks, with a particular emphasis on determining whether there are significant temporal changes in these feedbacks that would make them stronger or weaker during the 21st century. The model results indicate that one of the significant positive feedbacks on Arctic surface air temperature in winter weakens substantially toward the end of the 21st century. The feedback loop begins with a temperature increase that produces increases in water vapor, cloud cover, and cloud optical depth which increase the downward longwave flux by 30 Wm^-2 by 2060 which then increases the surface air temperature.

    Miller et al, Future regime shift in feedbacks during Arctic winter
    Geophysical Research Letters, Vol. 34 doi:10.1029/2007GL031826, 2007

    Shortly afterwards, the authors state:

    The amplification of high-latitude climate change results from complex positive feedbacks involving exchanges of energy and water mass between the ocean, sea ice, and atmosphere. The positive feedback related to changes in sea-ice albedo is one of the most frequently mentioned, however there are other positive feedbacks that are also important. Among these are feedbacks related to water vapor and clouds. Chen et al. [2003, 2006] demonstrated the importance of correctly representing in climate models the relationships among Arctic cloud and radiative properties. The present paper examines how some of these relationships and feedbacks may change in simulations of future climate.


    … citing some of the very same elements Graversen et al is concerned with — within the contexts of climate models. As with earlier studies, Miller et al argues that downward longwave flux plays an important role, one it gives centerstage, which is involved in a variety of positive feedback loops — which vary in strength and relative importance according to time and place (e.g., water vapor vs. cloud optical depth).


    Finally, the authors state that their results are consistent with a polar amplification being driven by an increased water vapor, leading to a polar amplification which is strongest during the winter due to increases in open water and latent heat flux — as modeled:

    Although this paper has not specifically examined the part of the feedback loop that produces the increase in atmospheric water vapor, this increase is consistent with modeled winter increases in open water and latent heat flux in the study region.

    I believe the albedo effect is most often mentioned as a cause of polar amplification because it is the easiest to understand. But judging from Miller et al (2007) at least and what it states with regard to literature, I find it difficult to believe that someone familiar with the literature would be unaware of other mechanisms being in play in model polar amplification.

    Comment by Timothy Chase — 5 Jan 2008 @ 2:18 AM

  40. wayne davidson (#33) wrote:

    Equally more common, moisture in the stratosphere. an indication of convection beyond tropopauses having weaker inversions.

    Below the tropopause at least (which is generally at pressures lower than 600 hPa, whereas this study focuses on 700 hPa or below), the following study would seem to support your view – although Siberia would appear to be an exception:

    The winter average trend shows decreases in inversion strength over the Chukchi Seas, with an average around –0.13 K yr^-1. The inversion strength also decreases over northern Europe with average rate around –0.13 K yr^-1. Inversion strength increases over north central Russia at rate around 0.10 K yr1, and increases in northeastern Russia, and also between Sevemaya Zemlya and North Pole at the rate of 0.13 K yr1. All the changes are statistically significant at the 90% or higher confidence level based on the F test….

    An analysis of the correlation between surface temperature and inversion strength trends, and between these two parameters and the Arctic Oscillation index, demonstrates the strong coupling between changes in surface temperature and changes in inversion strength. This is not surprising given that the primary control over surface-based inversions in the polar regions is radiation cooling. However, the analysis revealed that in some areas, trends in inversion strength are poorly correlated with trends in surface temperature, but more highly correlated with changes in large-scale circulation. Changes in inversion strength in areas such as the East Siberian Sea, for example, may therefore be a result of warm or cold air advection aloft rather than warming or cooling at the surface.

    Lui et al, Characteristics of Satellite-Derived Clear-Sky Atmospheric Temperature Inversion Strength in the Arctic, 1980–96, Journal of Climate Volume 19 (1 Oct 2006)

    Comment by Timothy Chase — 5 Jan 2008 @ 2:39 AM

  41. What is the difference between :-

    (a) Global Warming directly causing meltdown in the Arctic and

    (b) Climate Change (caused by Global Warming) causing changes in the Heat Transport system from the Tropics to the Arctic ?

    Net difference ? Diddly squat in real terms. Direct, local Global Warming has been accentuated by extra Heat Transport.

    So, the Meltdown is “worse than previously thought”, that is, there are more processes going on that simply local albedo effects from melting ice in the Arctic.

    It’s misleading and plain unhelpful for the Media to push the idea that somehow changes in the Heat Transport process are not caused by Global Warming, that is, Man-Made Global Warming.

    When I read this, I smelled the rat :-

    “January 2, 2008

    Natural causes as well as global warming may be causing Arctic thaw: study
    By Seth Borenstein, THE ASSOCIATED PRESS

    A new study suggests there’s more to the recent dramatic and alarming thawing of the Arctic region than can be explained by man-made global warming alone.

    Nature may also be pushing the Arctic to the edge. A study being published in the journal Nature says there’s a natural cause that may account for much of the Arctic warming, which has melted sea ice, ice sheets and glaciers.

    New research points a finger at a natural and cyclical increase in the amount of energy in the atmosphere that moves from south to north around the Arctic Circle.”


    However, apart from skeptical/sceptical news streams, this “story” seems to have died a death – because the counter-argument is so obvious.

    Thankfully this one can easily be made to go away. Not so the lack of balance at the BBC, who have published TWO “stories” on how compact fluorescents are bad for your health :-
    Low-energy bulbs ’cause migraine’
    2 January 2008
    Low-energy bulbs ‘worsen rashes’
    4 January 2008

    which of course the Daily Telegraph put as :-
    Low-energy bulbs ‘could cause skin cancer’

    Comment by jo — 5 Jan 2008 @ 7:19 AM

  42. “…claims to be a science writer and this article was in the Tuesday Science Times section. It is a fluff piece that reflects the intellectual laziness found in most of his writing, and about which he actually boasts in his NY Times personal page. Unfortunately, appearing in the Science Times, it will be taken seriously by many of the uninitiated. It is a mystery to me why the Times continues to sully its reputation with a guy like this.”

    I thought RC did not allow ad-hom attacks. I suspect that if I had submitted something similar about a pro AGW writer, it would have been censored.

    Comment by Steve Reynolds — 5 Jan 2008 @ 10:00 AM

  43. If models predict that Arctic temperatures will increase, most of all, way up in the
    troposphere when business as usual CO2 levels are plugged in, and if Graversen’s paper
    confirms that this is what has happened in recent decades, then are albedo changes
    responsible, or is an increased transport of heat from the tropics responsible? The
    answer to that simple science question is unclear. Mike Mc Cracken’s Post #13 is clear
    on that.
    RE: Press reports. The AP guy should have thought more and consulted more widely before
    jumping to the conclusion that, if it were true, would make everyone happy, which is
    that “its all a natural cycle”. The article could have been written more carefully.
    RE: How to best deal with the press? The lessons seem to be that Graversen should have
    checked out what the models predict, and that the referees should have caught the
    offending paragraph.


    Comment by meher engineer — 5 Jan 2008 @ 10:25 AM

  44. This seems to be simply an example of the final paragraph syndrome. You are trying to summarize the significance of your results in a few words and in a way that will get it past the gatekeepers at a high-profile journal, and it is easy to overreach. Sometimes it is caught before submission by the authors, or corrected in review, but I wouldn;’t be surprised if Nature sent the paper to measurement people rather than modelers, and it is easy to read over this kind of generalization without thinking about it too deeply.

    Usually, this kind of thing doesn’t much matter, as knowledgeable readers will take this kind of unsupported overreaching with a grain of salt. However, given the controversy (in the popular media, if not in the scientific literature), it is easy for something like this to get overblown.

    Comment by trrll — 5 Jan 2008 @ 10:30 AM

  45. off topic: congrats to Gavin for being named one of the Guardians “50 People Who Could Save the Planet”

    – back to my reading

    Comment by Thom — 5 Jan 2008 @ 1:00 PM

  46. I’m a Real-climate newbie and interested in learning about global warming. I wonder what the viability of this simplistic characterization would be about polar amplification. In winter time, there would be enhanced IR flux from greenhouse gases warming the poles relatively more so (given the stability and low surface temperatures) than at lower latitudes.

    In summer, short-wave radiation becomes more important, though with reduced warming (locally over the ice areas) due to the ice albedo and latent heat of melting considerations. Would this help account for a smaller warming signal over the Greenland and Antarctic ice caps?

    Are these factors reflected in the models?

    Comment by Steve Albers — 5 Jan 2008 @ 2:13 PM

  47. Re 42. Steve, I regret the last sentence, which is something of a cheap shot that I should not have included. However, I think the rest is legitimate criticism of his writing. I sent Tierney a rather long email, outlining the difficulties climate scientists face in trying to communicate their findings to the public, and urging him to use his considerable talents to help.

    Comment by Ron Taylor — 5 Jan 2008 @ 5:42 PM

  48. Gavin, I’m trying to reconcile the model run during winter (and comment to #16) with the line in the study:

    “amplification of the temperature trend during the dark months, November–February (Fig. 2). This amplification cannot be explained by snow-cover changes, as the albedo effect is practically absent during this dark period.”

    Is this due to the latent heat “release” spoken of in the next few lines? From what I get, then, summer is the only time where the ice-albedo feedback is nearly non-existant due to phase change. The latent heat is released into the atmosphere during autumn and that causes amplification in the atmosphere?

    [Response: Hmmm…. this isn’t something I’ve looked into in great depth, but my take would be that as temperatures increase, water vapour in air going poleward is higher and that leads to increased latent heat release when it condenses to make snow or rain. The ice-albedo feedback is most active in the spring and fall where it can make big differences to snow onset/melt dates. It is still active in the summer in the sea ice regions, but it doesn’t lead to large surface temperature changes because the presence (for the time being) of ice and open water means that any extra energy either goes into melting or into evaporation. But if readers have a more complete/better explanation I’m all ears… – gavin]

    Comment by Chris Colose — 5 Jan 2008 @ 6:27 PM

  49. My opinion is that when publishing, there is always the temptation to go beyond the conclusions made evident by data and discuss intuition or perhaps even to “get revenge” on a particular article felt to have overstated its conclusions. This is the sort of stuff editors and reviewers really beat out of authors and researchers have learned to keep it out of manuscripts sent for peer review.

    However, lately it seems that researchers are taking their “unpublishables” to the press.

    These are the quotes that struck me as maybe a bit misleading in that the author is “speaking” for other scientists.

    “It’s a remarkable result,” Graversen said. “I think nobody expected that.” and again “Retreating snow and ice cannot explain the vertical structure of the warming that we show,” Graversen said. “So snow and ice retreat is not as important as we previously thought.”

    Is that what Graverson has done here? Or perhaps the reporter pestered it out of him?

    Comment by Andrew — 5 Jan 2008 @ 7:48 PM

  50. Transient fluxes of heat and moisture (synopticians refer to them as real fluxes :-) ) are generally much larger than climatological transports, especially in midlatitudes. In time, huge blasts of warm, humid air into the arctic from lower latitudes are largely counteracted by parallel surges of cold, dry air from the arctic to lower latitudes. The result is that local climatological values of heat flux observed over a month or season are at least an order of magnitude lower than the day-to-day local fluxes. Consequently, relatively slight variations in transient fluxes can lead to relatively large fluctuations in climatological fluxes.

    The largest transports of heat in the lower troposphere are associated with intense mid-latitude cyclones and associated cross frontal circulations that are poorly resolved in GCM’s. It would not be surprising that GCM’s (and gridded global data sets dependent on spectral forecast models) underestimate the importance of these fluxes. Global models generally do not resolve the intensity of the mesoscale frontal and jet circulations that are responsible for local day-to-day variations in temperatures. The results of Graversen et al appear to be consistent with these limitations.

    However, global-warming deniers would be ill-advised to use these limitations to support their thesis. If anything, GCM’s underestimating the power of transient fluxes would lead to underpredictions of arctic warming.

    Comment by Werner Wintels — 5 Jan 2008 @ 7:51 PM

  51. Is it possible to change the subject? This is urgent.
    I just read a translation to Spanish, in La Tercera newspaper from Santiago, Chile, of a Dr David Whitehouse’s article,, arguing that Global warming has, temporarily or permanently, ceased, based on a fact that the “global temperature of 2007 is statistically the same as 2006 as well as every year since 2001”.
    Where is Whitehouse getting the data from? Is it real?
    For what I have seen, at least in Europe the 2006-2007 winter was the hottest in 150 years, I published a picture where you can see hundreds of people at a Spain’s beach tanning under the sun, days before 2006 Christmas.
    Was 2007 the “hottest year in history” as predicted by professor Phil Jones, from the East Anglia University?
    And finally who is Dr David Whitehouse? I could not find his bio.

    Comment by Jorge Ianiszewski — 5 Jan 2008 @ 8:34 PM

  52. RE #35 & 22, I do agree with you regarding the science contained in the various articles. Scientists cannot risk being the boy who called wolf. But they really should call wolf if it looks like one is coming. We know how that story ends…the wolf actually came and killed the villagers. Actually I think the villagers, and not the boy, are to blame.

    I guess what I was getting at is that the reviewers and editors (if not the authors), should be more vigilant of wording and (unsupported) claims that might end up misleading people to believe that GW is not human-caused or is not happening, since there may be greater damage in this. Regular vigilance then should be given to claims that AGW is happening.

    I know about peer-review. I’m dealing right now with making lots of corrections on an article I submitted, based on reviewers’ suggestions. Some minutely dealing with wording, and some pointing to my lack of evidence or support here and there, which happened when I tried to cut the paper down to the journal’s page limit, and cut out some references…so back go those references & I have to cut down the text somehow. I’m just thinking that the unsupported claim about models should never have passed peer-review (my reviewers would have picked up on it…they’re ruthless). The reviewers seemed to have done a sloppy job.

    Comment by Lynn Vincentnathan — 5 Jan 2008 @ 9:25 PM

  53. Hi, Gavin,

    I read the Nature paper. It is an intersesting paper and I agree with you that if the authors had analyzed the CMIP3 output, it would be much better. I also don’t think it is right to say that in the CGCM models the ice (snow) albedo feedback is the main mechanism for polar amplification.
    we [1] have recently published a paper and theoretically proved the feedback from heat transport greatly influence the vertical and meridional structure of global warming. It is important to point out the heat transport feedback does not have to warm the atmosphere only, it also can cause a larger surface warming by the concurrent other thermal-dynamic feedbacks.

    [1] Ming Cai & Jianhua Lu (2007),
    Dynamical greenhouse-plus feedback and polar warming amplification. Part II: meridional and vertical asymmetries of the global warming

    Climate Dynamics Vol 29:375-391
    doi 10.1007/s00382-007-0238-9

    [Response: Jianhua, thanks for providing the reference for us and our readers. This site is at its best when fellow scientists come through and provide pertinent information and constructive feedback. – mike]

    Comment by Jianhua Lu — 5 Jan 2008 @ 9:30 PM

  54. Jorge, no need to change the subject for that, it’s a common story.

    Comment by Hank Roberts — 5 Jan 2008 @ 9:40 PM

  55. Jorge Ianiszewski (51) wrote:

    I just read a translation to Spanish, in La Tercera newspaper from Santiago, Chile, of a Dr David Whitehouse’s article,, arguing that Global warming has, temporarily or permanently, ceased, based on a fact that the “global temperature of 2007 is statistically the same as 2006 as well as every year since 2001”.
    Where is Whitehouse getting the data from? Is it real?

    Oh, that article:

    Has global warming stopped?
    David Whitehouse
    Published 19 December 2007

    “Where is Whitehouse getting his data from?”

    Haven’t a clue. Doesn’t seem too keen to share it with us, either.

    “Is it real?”

    Well, you could try looking up the charts.

    But don’t worry, I will give you one with both the GISTEMP and HadCRU — although I should point out that the chart I am giving doesn’t end with the last few months of this year.

    Here you go:

    GISTEMP (NASA GISS) / HadCru (Hadley MET)

    Now here is the webpage:

    Garbage is Forever
    August 31, 2007

    GISTEMP is rising at a rate of 0.28 C per decade, plus or minus 0.19 C per decade. HadCRU is rising at the rate of 0.18 C per decade – plus or minus 0.16 C per decade. It doesn’t look to me like there is the exact cancelation that Whitehouse seems to think there is. As such, it is actually higher than the linear trend you get by going 1975 to present for NASA GISS (0.18+/-0.03 C/decade), but slightly lower than what you get from HadCRU for the same period (0.19+/-0.03 C/decade). I would check out the webpage — to learn a little about what gimmicks people can use when they want to lie with statistics, incidentally.

    Why the difference between GISTEMP and HadCRU? Mostly because GISTEMP includes the stuff above the Arctic circle but HadCRU doesn’t. The stuff that gets lopped off by HadCRU is where the greatest warming is taking place.

    The fact that the greatest warming takes place up there is called “polar amplification.” Why does it take place? Well, that actually brings us back pretty darn close to the topic of this post….

    You might want to check out my comment 39, though, and maybe even look up the article it references.

    Jorge Ianiszewski (51) wrote:

    And finally who is Dr David Whitehouse? I could not find his bio.

    You might want to read the bottom of the page you are linking to:

    David Whitehouse was BBC Science Correspondent 1988–1998, Science Editor BBC News Online 1998–2006 and the 2004 European Internet Journalist of the Year. He has a doctorate in astrophysics and is the author of The Sun: A Biography (John Wiley, 2005).] His website is …

    Comment by Timothy Chase — 5 Jan 2008 @ 9:43 PM

  56. Jorge Ianiszewski, re: 51
    Why on Earth do you want to go to the effort of translating that drivel. Whitehouse is yet another non-climate scientist who doesn’t understand climate. Yes, the current solar cycle started late. Yes, it looks like it might be a weak one as far as solar activity is concerned. It might even wind up affecting climate somewhat. However, any hiatus in solar activity will end–perhaps in a few years, perhaps a decade or two, perhaps even after 80 years as with the Maunder Minimum. And when it ends, the CO2 will still be there, and it will still be trapping heat, and things will go right on heating up for HUNDREDS of years. Only if we get a hiatus from warming, we will likely lose focus on greenhouse gasses and dump even more CO2 into the atmosphere, making the problem even worse.
    As to his statistical arguments, he should be ashamed of himself. The trend is still up–and the only way to avoid that conclusion is to cherrypick your starting point.

    Comment by Ray Ladbury — 5 Jan 2008 @ 10:18 PM

  57. But, don’t let us get sidetracked, right? It’s so easy to do.

    Comment by Hank Roberts — 5 Jan 2008 @ 11:34 PM

  58. Gavin;
    re your response to 48.
    One of the neat things about RC is the interdisciplanary weath of things that you would never encounter just reading Science ,Nature and JGR or Eos. Somewhere in the links above one learns that arctic refraction effects can lead to distorted images of the sun being visible 5 degrees below the horizon. If the red shift continues into the IR, can significant amounts of atmospheric radiation be refractively channeled across the terminator into the arctic winter dark , effectively bringing forward the edgewise onset of daylight warming before the arctic spring dawns? This is a shot in the dark question, and i apologize if it is quantitatively irrelevant, because I have no notion of atmospheric dispersion in the IR.

    Comment by Russell Seitz — 6 Jan 2008 @ 12:27 AM

  59. Russell, The effect seems to be due to temperature inversions, with greater refraction occurring in the layer of cold dense air, and less in the air above it. The images on the website certainly appear to suggest that blue light will be affected more than blue–consistent with rayleigh scattering. Wouldn’t this suggest that the effect will be less for IR than for shorter wavelengths. So, we’ll see it before it warms us. Also, remember that the Sun is not too bright in the IR.

    Some absolutely awesome stuff on that site, though–many thanks to Wayne Davidson for the reference, which I reproduce here just in case anybody missed it:

    Don’t miss the sunset pictures–one of the best blue-flash photos I’ve seen.

    Comment by Ray Ladbury — 6 Jan 2008 @ 7:25 AM

  60. RE #51, here is a way of conceptualizing denialist arguments that have been roundly rebutted by science time and time again: ZOMBIE LIES. One aspect is, the conventional wisdom is that the more wrong you are, the more credibility your opinion has about anything having to do with ___ (insert AGW). This might explain why denialist arguments never die, no matter how dead science seems to kill them.

    I saw a discussion of this in a Huffington Post article (though it was on a different topic):

    Comment by Lynn Vincentnathan — 6 Jan 2008 @ 9:21 AM

  61. Here’s another source:
    “…the red image of the Sun (or of some miraged part of it) sets or disappears first, followed by yellow, green, blue and violet….”

    Mike, I hope you can say more about the two papers (Cai and Lu, Lu and Cai, they are parts I and II) on theory once you’ve read them.

    Found the abstract:

    Comment by Hank Roberts — 6 Jan 2008 @ 10:11 AM

  62. Perhaps you could add the missing verbage that is indicated by the four periods between “feedbacks. ….Much” in your initial comments for the benefit of those of us who do not have a subscription to Nature. I for one tend to become concerned when one questions another’s comment or point of view without citing their comment or point of view in its entirety.


    Comment by drhealy — 6 Jan 2008 @ 12:25 PM

  63. … feedbacks. It is likely that a further substantial reduction of the summer ice-cover would strengthen these feedbacks and they could become the dominant mechanism underlying a future Arctic temperature amplification. Much …

    It changes nothing that Gavin et al. have commented on.

    Comment by P. Lewis — 6 Jan 2008 @ 2:33 PM

  64. Unrelated to this article, but now that it’s 2008, we’ve had exactly 10 years of “no warming since 1998″. Does someone want to write up a quick analysis of exactly how much warming we have had since 1998, and how well that correlates to model predictions? (From my calculations, roughly .2C – and since 1999 we’ve had almost .3C!)

    Comment by Dylan — 6 Jan 2008 @ 3:06 PM

  65. Probably the wrong place but, when is someone going to address the NASA report on sun spots and the prediction of 20 to 30 years of a colder planet? I think they are saying that a whole bunch of hot air will be leaving the web very soon.

    [Response: While NASA does forecast sunspot and solar activity, there are no NASA predictions of 20 years of a colder planet. Please look into your sources a little more carefully. – gavin ]

    Comment by pbview — 6 Jan 2008 @ 3:24 PM

  66. Ray Ladbury> …even after 80 years as with the Maunder Minimum. And when it ends, the CO2 will still be there, and it will still be trapping heat, and things will go right on heating up for HUNDREDS of years.

    I doubt that you can support that statement unless you are just talking about a small fraction of present CO2. The half-life of CO2 in the atmosphere is much less than 80 years.

    Comment by Steve Reynolds — 6 Jan 2008 @ 3:37 PM

  67. re: #65 pbview, yes wrong place, but…

    This is a common meme running around right now, so we can guess which blogs pbview relies on. Some of it seems to originate from John L. Casey’s “press release” at SSRC, amplified by the usual blogospheric behavior:

    Google: john casey changes sun’s surface next climate change

    I ran into this over at Jennifer marohasy’s blog, and said:

    “SSRC: you have to be kidding me: looks impressive! until you realize that:

    John L. Casey looks like a one-man-band apparently pushing consulting services based on some climate theory he has.

    His address is 4700 Millenia Blvd #175 Orlando FL, and if you Google that, you will discover an amazing number of companies that seem to be located in that office suite.

    That’s because the suite in this this impressive building isn’t even Casey’s own office, but is occupied by: Intelligent Office :

    “Intelligent Office locates your business in one of the best buildings in town. You’ll have a prestigious business address for your mail, your stationery and your advertising, as well as an impressive place to meet your clients. Your address with us will have your company’s name, not ours, and if you work from home, this is a great way to protect your privacy.”

    There is nothing obvious in Casey’s background to establish any particular expertise in climate science, no obvious presence in Google Scholar, and nothing before a recent press release. The info sounds like yet another “I’ve discovered cycles” thing, which happens all the time. Of course it could also be another “Carbon dioxide production by benthic bacteria..” scam, albeit on a much smaller scale (and if it is, I apologize in advance if that helps ruin somebody’s joke.) The website is 2 months’ old.

    Casey’s “press release” isn’t even up to Rob Ferguson’s standards. Casey “confirms” 18-month-old research from NASA, and has comments that certainly sound like Casey being interviewed by his own sock puppets.

    The NASA item referenced by Casey is about cycle 25; the one mentioned by another poster James Mayeau is about a different 200-year cycle [which is usually called the de Vries or Suess Cycle, although Casey talks like he found it himself]. In neither case was NASA telling people to expect another Maunder Minimum within the next decade or two. [Personally, I’d be delighted if the Sun cooled back like that, but it wouldn’t help very much.]

    4) This is another instance of standard arguments from:

    1 sun
    16 newice
    41 solarcycle

    or (see first chart especially; as usual, Wikipedia isn’t an authoritative reference, just a good start).

    All this stuff has been covered at RC many a time.

    Comment by John Mashey — 6 Jan 2008 @ 4:09 PM

  68. Speaking to the question of anthropoligical effects speeding GW over the arctic.

    Am I mistaken in my belief that (among other changes) we need to reduce high latitude air traffic during the winter months, when there is little sunlight to reflect and cloud cover tends to trap heat, while possibly increasing it during the summer to increase albedo over the region?

    Comment by Jerry Toman — 6 Jan 2008 @ 5:02 PM

  69. #58 Russell, I gave this IR boost idea some thought, it is a novel idea, and Ray got it right in #59, I expand on his explanation a little bit. Refraction occurs in all visible and invisible wavelengths. Whereas in visible light, the index of refraction for red is somewhat lesser than blue, this is clearly explained on Dr Andrew Young’s site:

    Where blue is displaced higher above the horizon than red, creating the 3 main sun colours over the horizon to get vertically displaced. Often misunderstood as Rayleigh scattering, refraction effects are numerous including the creation of 2 to 7 sun images on the horizon:

    These extra suns are created in ducts, where the entire sun disk is trapped and compressed in
    a thermal layer causing total internal refraction. These ducts can be short, a few Kilometers
    or long a thousands of Kilometers, and may in effect cause the sun to disappear in mid air, ie the not so famous Wegener blank strip.

    Refraction distributes EM from a point source, in this case the sun, not so hot in the IR but quite
    hot in UV. Where Rayleigh scattering is quite effective, even so, UV photons have been measured 2 or 3 weeks before the rise of the sun during the long arctic night at twilight (take my word for this, no reference, guys in Antarctica may confirm this). if there is any heat effects at all it would be in the blue and beyond wavelengths, don’t expect it to be huge, but it may be an important extra forcing component especially for the Polar or Antarctic long nights.

    Comment by wayne davidson — 6 Jan 2008 @ 5:15 PM

  70. Steve Reynolds Says:… The half-life of CO2 in the atmosphere is …

    Citation please? If you’ve come up with your own unique number from personal experiments, show us your method. Else your scientific cite?

    Comment by Hank Roberts — 6 Jan 2008 @ 5:54 PM

  71. Steve Reynolds said: “The half-life of CO2 in the atmosphere is much less than 80 years.”

    Actually it’s over a century. You should read Spencer Weart’s history–particularly:

    CO2 is a gift that keeps on giving. Keep in mind that the biosphere does not sequester CO2 indefinitely. In fact, more plantlife can wind up giving rise to more CH4, which has a much higher warming “bump” before it too becomes CO2. Planting trees is at most a delay, not a solution. And the oceans are already diminishing in their ability to absorb carbon.

    Comment by Ray Ladbury — 6 Jan 2008 @ 6:13 PM

  72. Re #68 (Jerry Toman)”Am I mistaken in my belief that (among other changes) we need to reduce high latitude air traffic during the winter months, when there is little sunlight to reflect and cloud cover tends to trap heat, while possibly increasing it during the summer to increase albedo over the region?”

    I would think yes, with regard to the second part of your belief. Air traffic anywhere, anytime pumps more CO2 into the atmosphere, and that will be around far longer than, and so, I would think, will greatly outweigh, any possible effect of an increase in albedo so far as warming is concerned. A large part of what leaves the atmosphere will add to ocean acidification. If you’re serious about slowing AGW, don’t fly unless you absolutely have to.

    Comment by Nick Gotts — 6 Jan 2008 @ 6:13 PM

  73. Re 59
    Thanks Ray. I was not thinking of solar IR radiation, but the fact that the atmospheric 5 to 15 micron emission may be channeled up and over the apparent horizon just as the solar image is even though it is out of the line of sight.

    My apologies for making the analogy mistakable for a long wave green flash- I’m wondering instead about the IR dispersion of the atmosphere considered as a pressure gradiated GRIN lens in the vibrational line regime.

    Comment by Russell Seitz — 6 Jan 2008 @ 6:15 PM

  74. Dylan, re #64. Actually, no, we’ve had 10 years of misinformed denialists claiming there has been no warming since 1998. 1998 was a big year for El Nino, so it is an outlier. You could look this stuff up on this site if your were so inclined.

    Comment by Ray Ladbury — 6 Jan 2008 @ 6:16 PM

  75. Steve Reynolds writes:

    [[The half-life of CO2 in the atmosphere is much less than 80 years.]]

    Try 200.

    Comment by Barton Paul Levenson — 6 Jan 2008 @ 6:36 PM

  76. The problem really seems to be with the AP reporter’s interpretation of the paper. What exactly does the phrase “natural and cyclic behavior” mean? The implication is that natural and cyclic behavior does not involve global warming.

    However, if you have an increase in poleward heat transport and no cooling in the equatorial zone, that can’t be interpreted as anything but global warming, just based on simple conservation of energy arguments. (Such conservation of energy arguments don’t apply to local albedo changes – but albedo is responsive to increased heat transport… in any case, scraping snow off the ground in the Arctic in the summer is unlikely to lead to a runaway albedo feedback effect…)

    The statement in the AP article that “Scientists are trying to figure out why the Arctic is warming and melting faster than computer models predict” is worth looking into, however. Perhaps comment #50 above gives some explanation:

    “If anything, GCM’s underestimating the power of transient fluxes would lead to underpredictions of arctic warming.”

    There’s also another route to warm the arctic ocean and thin the perennial sea ice, and that is oceanic heat transport. Trying to divide up the heat transport between oceanic and atmospheric routes appears non-trivial because there is a constant heat exchange between oceans and atmosphere that is related to things like wind speed and the amount of ice insulation. Furthermore, the ocean is slow to respond to forcings compared to the atmosphere. By the way, here is a NASA press release on changes Arctic oceanic circulation (Nov 2007) that seems to have some of the same problems that the AP article does! The press release states that “The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.”

    Again, the impression here is that the warming can be explained by ‘natural causes’ – but really, the article is about the switch from counterclockwise to a clockwise rotation. A better way of putting it would be that “natural cyclical changes are superimposed on a general warming trend – the outcomes are going to be complicated.”

    In the south, it also appears that melting in the West Antarctic has been accelerating, also according to NASA. Now, if the Arctic and Antarctic are melting, and the equator is not cooling, then there is no way that can be a ‘natural and cyclic process’ not related to global warming!

    The situation is complicated, but that’s no excuse for simplistic reporting. For example, some recent reports indicate that wind forcing of ice out of the Arctic Ocean is a major factor in the large open-water regions in the Arctic this past summer. However, that doesn’t mean a ‘natural cause’. Thick, broad sheets of perennial ice are resistant to wind forcing – but as the ice thins due to global warming, and sheets break up into fleets of icebergs, the sensitivity of ice masses to wind forcing increases.

    Anyone who fundamentally doubts that a small initial forcing can have a large effect on a system, out of all proportion to the initial forcing, might want to take a look at this: All fall down.

    Finally, the real blunder in the AP story is this:

    “The Nature study suggests there’s more behind it than global warming because the air a couple miles above the ground is warming more than calculated by the climate models.”

    That statement assumes that climate models are absolutely correct on global warming, so that if something happens that’s unpredicted, it must not be global warming, but rather a ‘natural effect’! Huh? That’s on top of the general theme here, the lack of references to actual climate model results in the paper.

    In that regard, reporters covering climate science might want to look at the following course lecture page, and see if they can answer the questions at the bottom, just to make sure they don’t make any more such embarrassing blunders (which, to be fair, are a more-or-less unavoidable side effect of scientific inquiry).

    Comment by Ike Solem — 6 Jan 2008 @ 6:56 PM

  77. #73 Russell, If there is a significant source of IR which may enter a duct, I don’t see why it can’t travel
    the same way as any visible or invisible light, its a question of direction, how would this IR have momentum such as light from a point source?

    Comment by wayne davidson — 6 Jan 2008 @ 6:56 PM

  78. (Note about the spam filter: It hadn’t occurred to me and I hadn’t seen it noted that the filter catches more than just intact words; e.g. in the case of this post it caught speCIA-LISist sans hyphen.)

    Re #13 response: At this point, it seems fair to say that all climate-related articles in Nature and Science are for public consumption, whether the authors intend it that way or not. There’s nothing about the problem that couldn’t have been caught and fixed by a non-specia-list editor. The substantive issue of the comparison with the model results aside, the phrasing was still very clumsy.

    That said, kudos to whichever one of the authors it was that came up with the idea of using that data source. It sounds as if it will be very useful for more than just this paper.

    Re #23: Er, Joe, how about an English major instead? :)

    Comment by Steve Bloom — 6 Jan 2008 @ 7:14 PM

  79. Re #71 and others: No need to look elsewhere for a good discussion of CO2 persistence. It seems to me that use of the term “half life” in this context, even if it can be defined, is inappropriate, since the decay is very much non-exponential.

    Comment by S. Molnar — 6 Jan 2008 @ 7:26 PM

  80. Ray Ladbury> Actually it’s over a century. You should read Spencer Weart’s history.

    How about an actual AGU paper by Moore and Braswell (1994)
    From their abstract:

    We note that the single half-life concept focuses upon the early decline of CO2 under a cutoff/decay scenario. If one assumes a terrestrial biosphere with a fertilization flux, then our best estimate is that the single half-life for excess CO2 lies within the range of 19 to 49 years, with a reasonable average being 31 years.

    As they say, decline slows after the initial reduction, but 1/2 is likely gone in about 30 years.

    Comment by Steve Reynolds — 6 Jan 2008 @ 8:38 PM

  81. re 69;
    I have some idea of how to relate dispersion to wavelength in solids where the Kramers -Croneig & Clausius-Mosetti relations hold, but lack any intuitive connection between waveguide theory that presumes a big step function between propagating and reflecting mediqa and gas channels , where the RI and , I assume , the dispersion is ~threeordersof magnitude smaller. For a lossless medium it just scales with distance, so 1000 kilometer pathlength may be realistic,but I’m still clueless as to the scattering freepath – how reflective is the ionosphere at low angles at say 10 microns ?

    Comment by Russell Seitz — 6 Jan 2008 @ 9:39 PM

  82. Steve, I am familiar with the Moore and Braswell paper.
    First, as I said before, the increased plant growth at most delays the issue, as plants eventually die and the CO2 goes back into the air. Neglecting this delay, the time constant they come up with is 92 years. Also, if you have less sun due to a sunspot minimum, you’ll have less plant growth.

    Second, as David Archer points out in the piece S. Molnar cites (thanks, I’d lost track of where I’d read this), a mean lifetime of several hundred years is more reasonable, but some of the increase relaxes only on geological scales.

    To assert that we’ll all be OK in a hundred years or so goes beyond optimism right into delusion.

    Comment by Ray Ladbury — 6 Jan 2008 @ 9:54 PM

  83. # 81, Russell, I am not familiar with Ionospheric refraction, these ducts exist at 10 to 500 meters above sea level,in the troposphere, right below manly isothermal layers within steep inversions.

    Comment by wayne davidson — 6 Jan 2008 @ 10:31 PM

  84. Re #74: Ray, I still see the “no warming since 1998″ line spouted out here and there. A quick write up and a nice graph showing that, even with 1998 being such an unusually warm year, the average temperature has still risen .2 degrees in the 10 years from 1998-2007, would be a nice retort to such posters.

    Comment by Dylan — 6 Jan 2008 @ 10:44 PM

  85. A question tangentially on topic: If a major source of the atmospheric transport is water vapor condensing to “clouds and snow” in the mid-upper Arctic troposphere, why doesn’t the snow, etc. mitigate the “snow melt” and in turn maybe the ice recession?

    Comment by Rod B — 6 Jan 2008 @ 10:45 PM

  86. ps I omitted (though it may be obvious anyway) that the release of the latent heat in the condensation is billed as a major source of the troposheric temperature rise….

    Comment by Rod B — 6 Jan 2008 @ 10:48 PM

  87. Dylan, several above have pointed to various answers to ‘since 1998′
    Try again:

    Rod, re “why doesn’t …” consider the quantities involved ….

    There’s more snowfall at higher elevations in Greenland, but the total mass balance is still negative, for example.

    Comment by Hank Roberts — 7 Jan 2008 @ 12:01 AM

  88. It is a joy to see Gavin’s and whole team’s work recognised by the Guardian as part the group of 50 people who can save the planet. In the course of writing our book, Apollo’s Fire:Igniting America’s Clean Energy Economy, we kept running into people on the cutting edge of technology who depended upon Real Climate both for baseline info and interpretation from an objective source. When people in the scientific community step up to the plate and help the broader community really understand the science involved, it is of inestimable value to us who are trying to move the ball in Congress. Great Work!

    [Response: Thanks for the kind words Congressman. It was a bit disappointing to see Bjorn Lomborg listed there, since for example his latest book “Cool It” truly misrepresents the science, as well as the economics, of the issue (more on that soon). However, we appreciate the recognition. Keep up the great work yourself! – mike]

    Comment by Congressman Jay Inslee — 7 Jan 2008 @ 12:21 AM

  89. The real culprit in this story seems to me to be Borenstein’s exceedingly sloppy AP story, perhaps nudged along by something badly phrased said by Graverson in the interview. The actual statement in the article, which Gavin fairly calls into question, is pretty ambiguous, which is its main fault. I can see a reading of their prose that is fairly innocuous; when I talked to one of the authors in Stockholm earlier this fall, he expressed a clear interest in looking at the AR4 archive to see if the effect is there. That suggests strongly that there wasn’t any a priori assumption that models are wrong about this.

    Regarding the ambiguity of the phrasing, remember these are Swedes writing in English, and while Swedes are outstanding linguists (coming from a small country where hardly anybody outside speaks their language) nuances are the hardest thing to translate. On top of that, Nature has its own copy-editors who in my experience sometimes change the meaning in their efforts to “improve” the understandability of the prose. Authors get to see this, but they have to flag it and complain if something goes awry. I’ve asked one of the authors I know to comment on their intent here. They’re good scientists, and I’m sure they did not intend any harm.

    Now, let me emphasize the really remarkable thing about this result, if it holds up. The neat thing is that the heat flux increases even though (through polar amplification) the temperature gradient is weakening. My first reaction was “aha, latent heat!” but Michael Tjernström (back in September) told me they looked at that, and it’s mostly sensible heat increases doing the trick. That means there is some really interesting dynamics going on — some effect of changes in horizontal shear, maybe some feedback from lapse rate changes, maybe something associated with poleward migration of storm tracks. I really hope this result holds up, since if it does that’s more cool work to be done by dynamicists in understanding what is going on. Think of the possible repercussions for the unsolved problem of maintaining an ice-free state in the Cretaceous!

    [Response: I would second this. There may be something very interesting to learn in investigating the AR4/CMIP3 multi-model ensemble to see whether or not this observation holds up in current generation models and, if not, what features in the meridional heat transport budget appear to differ. As for unsolved problems such as the “equable climate” problem (i.e., the ice-free poles and reduced meridional temperature gradient in some deep time paleoclimate periods), there are some intriguing alternative explanations already out there, such as (first posed by Kerry Emanuel) feedbacks between warming tropics, tropical cyclone activity, and associated upper ocean mixing, see e.g. Sriver and Huber (Nature, 2007) – mike]

    Comment by raypierre — 7 Jan 2008 @ 12:47 AM

  90. Needless to say, I am extremely pleased and impressed that congressman Jay Inslee checked in to congratulate Gavin on his well deserved recognition. If members of Congress are checking in on Real Climate, perhaps there is some hope that this country might develop some policies necessary to deal with this problem!

    Comment by Jim Eaton — 7 Jan 2008 @ 1:45 AM

  91. #83
    Got ,Wayne- the question is one of the acceptance angle for emitted IR ray paths refracted from under the horizon through a near surface mirage inversion- So I can assume a few % density contrast per 10 Kelvins.

    Comment by Russell Seitz — 7 Jan 2008 @ 2:38 AM

  92. #90 raypierre,

    given that statement, what would you say about my comment #48 (And gavin’s response?). Gavin’s explanation makes sense, and would probably be a quick hypothesis I would give if my professor asked me. I would not think that sensible heat is sufficiently strong here, but this is interesting.

    Comment by Chris Colose — 7 Jan 2008 @ 2:59 AM

  93. Talking about high profile papers, has anyone got anything on the alleged prediction by the Russian academy of science that solar cycles 24 and 25 will take us straight back into a little ice age, and there will be no/ very few sunspots? It looks very dodgy, but of course denialists are starting to use it as an excuse not to do anything, never mind the small problem of ocean acidification.

    Comment by guthrie — 7 Jan 2008 @ 5:02 AM

  94. Re: #51

    Where is Whitehouse getting the data from? Is it real?

    From the Hadley/CRU surface temperature record. The Hadley surface temperature anomalies for this century so far (i.e. 2001-2007) are as follows: 0.40, 0.46, 0.47, 0.45, 0.48, 0.42, 0.41 (up to Nov).

    Whitehouse (whoever he is) therefore appears to be correct in his statement regarding the lack of significant difference between the years, though he may be a bit premature in declaring that the “warming is over”.

    Was 2007 the “hottest year in history” as predicted by professor Phil Jones, from the East Anglia University?

    The prediction was that there was a 60% chance that the 1998 record of 0.52 deg C would be exceeded in 2007. The actual prediction was for an anomaly of 0.54 deg C (0.38-0.70; 95% CI). If they’re lucky the final value for the year will just fall inside the low end of their specified 95% confidence range. We can assume, therefore, that Hadley thought there was something less than a 5% (nearer 2.5%) probability that the global temperature would be as low as it actually is.

    Comment by John Finn — 7 Jan 2008 @ 5:04 AM

  95. #90: “..poleward migration of storm tracks …”

    Everybody is obsessed by storms. They are spectacular, do a lot of damage and transport plenty of energy. Good reasons.

    I am obsessed by a semi-permanent blocking high that seems to steer those storms over much of the north. Like hurricanes, storms do not have a will of their own but move in paths determined by their surroundings. In America for some reason the jet stream is frequently mentioned, in Europe very seldom, if ever.

    There is a nearly permanent area of high pressure over Siberia and Central Asia. For some reason last summer this fair weather expanded or moved to cover much of the Arctic, and was instrumental in the exceptional sea ice melting (with other factors). Most of time the western edge of that same blocking high determines if the Atlantic depressions hit Europe or pass it by on a more northerly track.

    How far west the high extends and the shape of it largely determines the type of weather in Europe. Some ten years ago there was an impressive display. A train of rather compact Atlantic depressions passed over France, proceeded the length of a hot Mediterranean picking up humidity, hit a stonewall north of Turkey and was forced on an unusual path towards northwest. The result was a week of torrential rains in southern Scandinavia and extensive flood damage.

    Why is this high there in the first place? I do not know, maybe something to do also with plain geography. The Americas have the Rockies and Andes, running north to south. Eurasia has mountain ranges running from east to west, China to Spain. Features that reach to mid-tropospheric heights.

    Warming surely affects everyday weather. Still, IMHO it is simply not knowable what the exact impacts are on a daily and local basis. Maybe changes of a semi-permanent, large and influential feature could be more tractable. Also even a slight expansion to the west would steer more Atlantic storms (and their energy) to the Arctic – a possible feedback mechanism.

    Just musings of an amateur, of course …

    Comment by Pekka Kostamo — 7 Jan 2008 @ 5:59 AM

  96. A few people have belittled the topic of this post:

    A national newspaper, a Conservative bent, no class nor scruples, a readership of 100,000s. That’s why its important.

    Comment by bigcitylib — 7 Jan 2008 @ 8:59 AM

  97. > latent heat … sensible heat …?

    Speculating from hang-gliding experience, I looked up ‘orographic’ and ‘Greenland’ and found, for example, this discussion:

    ——brief excerpt——-

    … low-level jet streams … form in stratified flow downstream of the vertex of large elliptical barriers such as the southern tip of Greenland, hereafter referred to as “tip jets”. The tip jet dynamics are governed by conservation of Bernouli function as parcels accelerate down the pressure gradient during orographic descent. In some circumstances, the Greenland tip jet is influenced by baroclinic effects such as differential horizontal (cross-stream) thermal advection and/or vertical shear. In contrast, in the barotropic situation upstream flow is diverted around and over the obstacle into laminar (Bernouli conservation) and turbulent (Bernouli deficit) regimes, respectively. In both situations, a downstream geostrophic balance is achieved, characterized by baroclinicity and vertical shear associated with the surface-based tip-jet front. … Enhanced surface-based forcing of the ocean circulation occurs in the region of the tip jet core through large air-sea energy exchange (upward surface-heat fluxes > 800 W/m-2), and at the tip jet flank ….

    ——end excerpt——-

    800 watts per square meter heat flux is interesting, isn’t it?

    Comment by Hank Roberts — 7 Jan 2008 @ 9:44 AM

    He’s on a list of 50 possibles:

    [Response: You don’t want to believe everything you read in the newspapers…. – gavin]

    [Response: Well, when you read what they wrote it was really “RealClimate” they were awarding this too. Sort of like IPCC being awarded a Nobel Prize. Of course, they had to choose a “person” in this case. Gavin is a co-founder, and has been by far the most active of us over the past couple years, so the best choice in that regard. But the others of us who co-founded and/or contribute regularly to the site can take some satisfication for this recognition, even if we have to share it w/ Lomborg :( – mike]

    Comment by veritas36 — 7 Jan 2008 @ 11:35 AM

  99. re 97
    While this paper notes the applicability of the effect to other locations (e.g., Antarctica) it neglects to note that Greenland is unique in that it has two tips generating vortices. I suppose this was less of an issue then, as the sea ice reduced heat exchange between the Arctic Ocean and the atmosphere. Now that there is less sea ice, the heat fluxes associated with the northern vortex are – larger..

    Comment by Aaron Lewis — 7 Jan 2008 @ 12:32 PM

  100. Re: 98

    The Guardian fails to fully realize that the description of a problem, does not directly equate to the solution of that same problem. Their choice of using the phrase “save the planet” implies we are on the “solution side of the problem”, instead of the “description side of the problem”.

    If we use the “savior” term now, what will be left for later? “Grand exalted pooba” ;-)

    Comment by Russell — 7 Jan 2008 @ 12:52 PM

  101. Talking about high profile papers, has anyone got anything on the alleged prediction by the Russian academy of science that solar cycles 24 and 25 will take us straight back into a little ice age, and there will be no/ very few sunspots?

    I imagine you’re talking about that piece put up by ONE MEMBER of the Russian Academy of Science???

    Comment by dhogaza — 7 Jan 2008 @ 1:44 PM

  102. > 97
    Yep, that was just a random grab by an uneducated reader to note there’s work available. Interesting that the Navy was looking into this issue a decade or more ago. I’m sure there’s more, don’t consider that one paper a best answer, just a possible clue about where the heating may happen and where it may go.

    Comment by Hank Roberts — 7 Jan 2008 @ 2:41 PM

  103. Mike (inline to #89) wrote:

    As for unsolved problems such as the “equable climate” problem (i.e., the ice-free poles and reduced meridional temperature gradient in some deep time paleoclimate periods), there are some intriguing alternative explanations already out there, such as (first posed by Kerry Emanuel) feedbacks between warming tropics, tropical cyclone activity, and associated upper ocean mixing, see e.g. Sriver and Huber (Nature, 2007) – mike

    I was thinking about the Sriver and Huber paper. Oceanic advection has also been mentioned not too long ago as one element that models may have been underestimating due to low resolution. Presumably, Wieslaw Maslowski is doing a better job of capturing the oceanic advection in the artic which is melting the ice from below and thus of explaining the trend in Arctic sea-ice using a higher resolution model. Their model predicts 2013 without taking into account the data from either 2005 or 2007.

    And of course it is my understanding that poleward atmospheric and oceanic heat transport are likely strongly coupled. And while I am not sure how important this is, 2005 was a record year for hurricane activity in the Atlantic, and 2006 was a record year for hurricane/cyclone activity worldwide — with the Pacific picking upon the Atlantic’s slack. However, at least with regard to Sriver and Huber, having no background, I do not know how important the mechanism would be inasmuch as they seemed to be estimating that hurricanes were responsible for 15% of poleward heat transport tops.


    For those who are interested, Nature has an Open Access copy of Sriver and Huber (2007) at:

    Comment by Timothy Chase — 7 Jan 2008 @ 2:51 PM

  104. Re: #72 Actually Nick, I was more concerned about winter (night) effects, as per this article:

    Night flights give bigger boost to global warming
    14 June 2006 news service
    Richard Fisher

    THE romance of night flight has inspired all kinds of artists, from writers to rock musicians. Rather less romantic is the impact of night-time flights on global warming revealed by an analysis of aircraft movements over England.

    Aircraft contrails – the streams of water droplets and ice that form when hot exhaust meets cold, moist air – can persist for many hours, spreading to an average width of 2 kilometres before dispersing. They are known to contribute to global warming by trapping the infrared radiation emitted from the Earth’s surface (New Scientist, 19 October 2002, p 6).

    Nicola Stuber of the University of Reading, UK, and her colleagues used computer models to study the warming effect of contrails created by aircraft entering the North Atlantic flight corridor over south-east England. This showed, as expected, that winter flights make a disproportionate contribution to warming because winter weather favours the formation of contrails.

    More striking was the difference between night and day. While night flights accounted for only 25 per cent of air traffic at the monitored site, their contrails contributed up to 80 per cent of the warming in cloud-free conditions. That’s because daytime contrails partly offset the overall warming effect by blocking incoming sunlight (Nature, vol 441, p 864).

    The team also showed that the 36 per cent of flights over the US east coast that occur during the night account for 53 per cent of the warming. The 48 per cent of all flights in the North Atlantic corridor that are at night account for 58 per cent of the warming. The simplest way to minimise the warming effect of contrails would be to reschedule flights for the daytime, Stuber says.

    Bob Noland of Imperial College London, who also works on contrail-induced warming, says this research should help persuade a sceptical aviation industry to address the issue. “They’ve done a fine job, using well-established data,” he says of Stuber’s team.

    But shifting all night traffic to the daytime would be unrealistic, he says. Instead, he suggests planes should be manoeuvred around regions where contrails would form, just as they avoid thunderstorms. However, Stuber says it is difficult to forecast conditions that favour the formation of contrails.

    Comment by Jerry Toman — 7 Jan 2008 @ 3:29 PM

  105. Re #100

    Grand Exhaulted Poobah is too pretentious. Why not simply “The Wizard of On” referring to Louis M. Michaud, of Sarnia, Ontario, Canada, the inventor of the “technology” most likely to save the world, the “Atmospheric Vortex Engine”. Meanwhile, there will be opportunities to nominate him for a Nobel Prize BOTH for Peace and Physics.

    Of course there is still time for Gavin, as well as the other Founders and Contributers here at to claim the title of “Assistant Wizards” by signing off on the technology in group fashion in order to get its development in motion more quickly.

    AVE_fan #1

    Comment by Jerry Toman — 7 Jan 2008 @ 3:43 PM

  106. PS to 103

    As I remember, Sriver and Huber were focusing on oceanic polward heat transport, but it seems obvious that this would apply equally to the atmosphere. One point: presumably we had been thinking of hurricanes as mostly local, not having the kind of global effect that Sriver and Huber describe, although according to Mike the view that they may have a global effect actually goes back to Emanuel. 2003 I would presume. However, I remember myself as having thought of their heat transport as essentially vertical before I started digging into any of this stuff. Ad hoc air conditioning units for the planet, I suppose.

    However, with increased convective vertical heat transport due to moist air convection, qualitatively at least, I would expect both the atmosphere and ocean to more easily re-organize itself horizontally. This would be a form of self-organization. Moreover, as this involves convection with structure at various levels and positive feedbacks by which more efficient paths of heat transport are “chosen,” I would expect models to do a better job of capturing this sort of phenomena with higher resolution and to underestimate its effects with lower resolution.


    One more point: I remembered from my evo days that presumably hurricanes couldn’t get above 40 mph windspeed — much like bumblebees can’t fly. But the trick with the bumblebees is a reliance upon turbulence generated by their velvety coat. And with hurricanes, presumably the water droplets from sea spray serve to lubricate their winds so that they can achieve much higher speeds despite the viscosity of air.

    Looking it up just now I found the following two articles:

    Ocean Spray Lubricates Hurricane Winds
    ScienceDaily (Jul. 26, 2005)

    Barenblatt et al., The turbulent wall jet: A triple-layered structure and incomplete similarity (2005), PNAS, Vol. 102, Issue 25, pp. 8850-8853

    Now one question: the sea spray water droplets are able to kick into action well below 40 mph (64 kph) at just over 25 mph (40 kph). So would water droplets play a similiar role in poleward convection? Or would their role in this be limited to fascilitating vertical transport and thereby facilitating poleward transport only insofar as vertical transport sets up conditions under which poleward transport arises through spontaneous self-organization?

    Comment by Timothy Chase — 7 Jan 2008 @ 4:15 PM

  107. I had provided the link to:

    Editor’s Summary
    31 May 2007
    Cyclones in the mix

    … earlier for the Sriver and Huber (2005) on how hurricanes may fascilitate poleward oceanic heat transport. The link to an open access copy is there.

    However, it also includes a link to the news article:

    Churn, churn, churn
    How the oceans mix their waters is key to understanding future climate change. Yet scientists have a long way to go to unravel the mysteries of the deep. Quirin Schiermeier reports.

    This mentions Kerry Emanuel’s view that hurricanes might play such a role as being expressed back in 2001 among other things. Stuff to explore.

    And yes — I am just trying to stir the pot at this point.

    [Response: Thanks for your comments Timothy. Thus far, the impact of TC-related ocean mixing and heat transport on global climate has been looked at rather crudely. It will take some time for this to implemented in models (ocean-only and ultimately coupled models) in a realistic enough way that we can draw more firm conclusions. You can expect to hear more about this in the months and years ahead. But, in my view, its the best current prospect for explaining our way out of the ‘equable climate’ paleoclimate problem and perhaps, we may learn, other current inconsistencies as well. This is the way science is supposed to work. Stay tuned! -mike]

    Comment by Timothy Chase — 7 Jan 2008 @ 4:33 PM

  108. I took a closer look at the Nature news article “Churn, Churn, Churn” I gave a link to above.

    It mentions the how, if hurricanes play a stronger role in shaping heat transport in warmer climates this may help to explain the near Mediterranean conditions the Arctic enjoyed during the Eocene — something that Raypierre expressed an interest in back in 89.

    It states that tides evidently play a much larger role in ocean mixing that proceeds along the ocean bottom — and that this may prove to be important to models.

    It also mentions that Earth and Space Research Institute is in Seattle where Robin Muench lead a group focusing on the rate of mixing in the oceans, both as a whole and in specific regions. Eric might want to give him a call and have a coffee if that sort of information might be of value to Gavin.

    Comment by Timothy Chase — 7 Jan 2008 @ 5:44 PM

  109. > 800 watts per square meter heat flux is interesting, isn’t it?

    Yes. Mainly since it was the only intelligible phrase in the whole paragraph! [;>)

    Comment by Rod B — 7 Jan 2008 @ 6:46 PM

  110. Re # 56, 66, 70, 71, 75, 79, 80 and 82: The 2005 RealClimate post by David Archer referred to by #79 on the lifetime of anthropogenic CO2 in the atmosphere was updated by his later publication [1]. In it Archer states:

    “The idea that anthropogenic CO2 release may affect the climate of the earth for hundreds of thousands of years has not reached general public acceptance. …”

    “The carbon cycle of the biosphere will take a long time to completely sequester anthropogenic CO2. … The mean lifetime of fossil fuel CO2 is about 30-35 kyr. …”

    “… if the fate of anthropogenic carbon must be boiled down into a single number for popular discussion, then 300 years is a sensible number to choose, because it captures the behaviour of the majority of the carbon. … However, the 300 year simplification misses the immense longevity of the tail on the CO2 lifetime, and hence its interaction with major ice sheets, ocean methane clathrate deposits, and future glacial/interglacial cycles. … A better approximation of the lifetime of fossil fuel CO2 for public discussion might be ‘300 years, plus 25% that lasts forever.'”

    The IPCC AR4 cites Archer’s paper when stating, “about 50% of an increase in atmospheric CO2 will be removed within 30 years, a further 30% will be removed within a few centuries and the remaining 20% may remain in the atmosphere for many thousands of years.” [2]

    So, while Steve Reynolds (#66) is correct that, “the half-life of CO2 in the atmosphere is much less than 80 years” in the sense that 50% is removed in 30 years, Archer’s work indicates that Ray Ladbury (#56) is also correct to refer to the effect of anthropogenic CO2 emissions being felt for hundreds of years. Nice to settle an argument by both being right :-)


    [1] Archer D (2005), ‘Fate of fossil fuel CO2 in geologic time’ Journal of Geophysical Research Vol 110, C09S05, doi:10.1029/2004JC002625.

    [2] IPCC (2007), Climate Change 2007: The Physical Science Basis. Contribution of WGI to the AR4, Ch 7, p 514. Available at

    Comment by Chris McGrath — 7 Jan 2008 @ 7:25 PM

  111. Chris McGrath, the ~30 year # is the time for most of the excess CO2 to make its way into the biosphere–but this does not remove it from the climate. Rather, unless we grow a lot of redwoods, in a few decades much of the carbon gets back into the air, some as CH4, with a higher gh potential. Moore and Braswell say themselves that ignoring the biosphere, the half-life is closer to 92 years. Moreover, if we have cooling due to decreased insolation, this would adversely affect plant growth, and the uptake would be even slower.

    Comment by Ray Ladbury — 7 Jan 2008 @ 9:00 PM

  112. “Half-life” is misleading and not the description used by anyone in the field.

    A half-life describes radioactivity — a process that is going to go on at the same rate regardless of anything happening in the environment. No feedback, no forcing, nothing changes.

    Applied to biogeochemical cycling, it suggests, falsely, a steady rate of removal.

    Comment by Hank Roberts — 7 Jan 2008 @ 9:17 PM

  113. CORRECTION to 106 (sea spray and hurricane formation)

    For sea spray reducing the viscocity of air and thus making it possible for hurricanes to be far more powerful than they would otherwise be, I had given after a quick search:

    Barenblatt et al., The turbulent wall jet: A triple-layered structure and incomplete similarity (2005), PNAS, Vol. 102, Issue 25, pp. 8850-8853

    However, the correct paper is:

    Barenblatt et al., A note concerning the Lighthill “sandwich model” of tropical cyclones (2005), PNAS, Vol. 102, Issue 32, pp. 11148-11150

    Same authors, same periodical, same year and related topics, but obviously not the same paper. And yes, it is open access.

    Comment by Timothy Chase — 7 Jan 2008 @ 9:18 PM

  114. [Response: You don’t want to believe everything you read in the newspapers…. – gavin]

    I don’t believe everything I read in the papers, but I believe this! I realize that Gavin is the flag bearer for all the heavy hitters(to add to Congressman Inslee’s analogy of stepping up to the plate) that run RC,including the guest hosts like Figen who posted earlier. The Lonborg’s of the world are necessary as well. What’s the point of running for a touchdown if the opposing team is sitting on the bench?
    The only modification might be that instead of saving the planet, which will survive with or without homo sapiens, at least they have the potential of saving civilization. Especially if more decision makers like the Congressman come aboard.

    Inserting the period 1979-2001 and Jul-Aug. in the pull down menu for the model runs referred to in the lead article does indeed show small(-0.1 to +0.3C)for surface change temperatures in the Arctic, and more heating at higher altitudes, if I’m reading the results correctly.In addition, the global mean graph shows a gradual heating from the surface to about 300 mb and then a more rapid cooling in the upper atmosphere.

    Comment by Lawrence Brown — 7 Jan 2008 @ 9:52 PM

  115. #91 Russell. Got something to ponder, cross two Polaroid sheets perpendicularly, no visible light gets through, in the case of thermal layers having UV or IR take a look at this sequence inspired and executed by Physicist Gunther Kletetschka, first a sunrise without ducts:

    The problem is to differentiate between UV and IR, UV should refract above the sun disk and IR below, clouds and moisture may show as IR.

    Now a sunset with a thermal duct or three:

    THere are artifacts, still unknown, in the last cross Polaroid pictures, if you look
    at the visual to Polatroid sequences, there is a tripling of the sun line, is the top one UV? Unknown, but this testing can be repeated and Ill try to find out.

    Comment by wayne davidson — 7 Jan 2008 @ 11:10 PM

  116. Lawrence Brown: interesting post, but something bothers me in your outlook. The Lomborgs of the world are not necessary, they are a nuisance, as are advocates from the opposite side who disregard reality for ideology. This is not a football game or a courtroom argument. Nature does not give a damn about our bickerings, it does not need to be given a voice, it is the only authority. Way too much BS is already out there under the pretext of “balancing views.” Balance is of interest only if it is grounded in firm scientific underpinnings and stems from a genuine desire to understand, both of which exclude Lomborg and ideologues in general. Understanding the workings of Nature is the function of science, it must supercede all ideological predispositions. Only when we accept that fact will we have a real future as a species, in which we’ll be somewhat responsible.

    Comment by Philippe Chantreau — 7 Jan 2008 @ 11:29 PM

  117. Re #111, Ray, not being a climate scientist or an ocean chemist (as Archer is) and just trying to understand this issue by reading the IPCC AR4, Archer (2005), and Archer’s 2007 text, Global Warming: Understanding the Forecast (Ch 10 of which deals with the perturbed carbon cycle), I understand a major sink for fossil CO2 emissions in the short and medium terms is the ocean based on chemical (not biological) dissolution of CO2 into carbonic acid, bicarbonate and carbonate ions.

    Re # 112, Hank, point taken. I was trying to incorporate Steve’s earlier terminology because both he and Ray seemed to be making valid (if somewhat incomplete) points.

    Comment by Chris McGrath — 8 Jan 2008 @ 3:28 AM

  118. Many congratulations to Gavin and to the entire RC team. RC is truly a phenomenal blog site which I believe has already changed the world by making extremely accomplished scientists and their ideas accessible to the public. What makes RC invaluable is not just the high quality of its posts, but also the way it operates behind the scenes and the creative, thoughtful and courteous community of readers and commenters it cultivates and supports.
    When I first approached Gavin (through e-mail) to ask if I could do some translations for RC, I didn’t know him and actually only knew one of the 11 editors of the site. All the editors here are high profile scientists with very impressive publication records. So I felt nervous about wanting to participate on RC thinking I won’t measure up. Gavin was open and welcoming, and later when I submitted a post he and the rest of the team were extremely supportive. All posts go through peer review here and the process is tough but I learned so much!! So they aren’t just doing a service for the general public but for scientists like myself by providing us with support and exposure to the general public (I am one of the most recent guest hosts here but they have had many others like me). And I use RC as a teaching tool in class by not only having my students read their posts but encouraging them to post comments. And so the community grows. I think that alone is a huge contribution to civilization.
    Many congratulations again.
    The mystery for me is this is a huge effort on their part, so how do they find the time for producing all this science as well as running RC? Do they somehow have 30 hours in their day? :)

    Comment by Figen Mekik — 8 Jan 2008 @ 5:14 AM

  119. Re 116: Yes, thank you Phillippe for the correction.On thinking it over, the serial naysayers are a net minus,placing obstructions in the path of progress. If they are of any worth at all, it’s to keep the rest of us on our toes as to what faux attribution regarding global warming they’ll come with next.

    Comment by Lawrence Brown — 8 Jan 2008 @ 7:20 PM

  120. “…..If they are of any worth at all, it’s to keep the rest of us on our toes….”

    It’s a tough job, but somebody has to do it…

    Comment by Rod B — 8 Jan 2008 @ 9:14 PM

  121. We are pleased to see the lively discussion here related to our recent study on the Arctic warming amplification.

    We state in the final paragraph of our paper that “Our results do not imply that studies based on models forced by anticipated future CO2 levels are misleading when they point to the importance of the snow and ice feedbacks”. We mean just that: models showing a connection between an amplified warming in the Arctic and the ice-albedo feedback mechanism do not have to be wrong. We welcome a model intercomparison study dealing more in depth with this question, but that was beyond the scope of our study.

    In some media, it has been claimed that we find evidence suggesting that natural variability underlies much of the recent Arctic climate change. In our paper we show that a shift in the northward energy transport into the Arctic has played a considerable role for the Arctic amplification; we do not know whether this shift is due to natural variability or if it is anthropogenically induced.

    R. G. Graversen, T. Mauritsen, M. Tjernström, E. Källén and G. Svensson, Stockholm University, Sweden.

    [Response: Thanks for stopping by. Do you have an idea why some of the media reports got this wrong? – gavin]

    Comment by Graversen et al. — 9 Jan 2008 @ 5:14 AM

  122. RE #112: Hank Roberts @ 9:17 PM:

    Hank, there is another scientific field in which the term “half-life” is used, and that is pharmacokinetics (a subject near and dear to my heart). For more complex systems (with compartments), there are parameters for absorption, distribution and finally elimination. We might think of the organic parts of the carbon cycle as the distribution phase (in which there is exchange between tissue and the circulation) and mineralization as elimination.

    Comment by Deech56 — 9 Jan 2008 @ 6:14 AM

  123. I know it’s off-topic for this thread, but I have a question concerning the latest IPCC report.

    In chapter 2 of the WG1 section of the 4thAR, section 2.4.5 discusses aerosol cloud albedo effect. Figure 2-14 shows graphically the cloud albedo forcing results of 28 GCM runs. See here: (page 177)

    After a lengthy discussion of the various issues involved in estimating this particular forcing, the authors summarize on page 180 as follows:

    “Based on the results from all the modeling studies shown in Figure 2.14, compared to the TAR it is now possible to present a best estimate for the cloud albedo RF of –0.7 W m–2 as the median, with a 5 to 95% range of –0.3 to –1.8 W m–2.”

    However, according to my Excel spreadsheet, the median of the data shown in figure 2-14 is not -.7 — the median is actually -.99. (The values that were graphed in Figure 2-14 are shown in Table 2.7, pages 174 – 176. I used the values from that table. Note that only the values shown in bold were included in Figure 2.14, so those were the ones I used.)

    Does anyone know how they came up with a median of -.7 instead of -.99?

    I also don’t see how they came up with that confidence interval. According to my Excel spreadsheet, +/- 2 sigma on the data in the table is -.12 to -1.87. Does anyone know how they derived their confidence interval?

    Comment by Michael Smith — 9 Jan 2008 @ 7:15 AM

  124. RE # 121

    Dr.Graversen et al.,

    Have you submitted a letter of clarification to the editor of any of the papers in which Seth Bernstein’s article was posted? I believe that would help clear things up.

    Comment by John L. McCormick — 9 Jan 2008 @ 8:49 AM

  125. RE: The 50 people…With special attention to #118 and as evidenced by;#121.

    Saving the world may or may be an exaggeration, but Gavin is certainly in a league with Eric Clapton.

    Thanks to Gavin and everyone else here who has made this a great place to learn and clear the air.

    Comment by Arch Stanton — 9 Jan 2008 @ 10:05 AM

  126. > pharmacokinetics half-life
    — That’s a great nitpick.

    But I doubt wossname was using ‘half-life’ to mean that kind of biological rate of change. He’d be endorsing the Gaia Hypothesis:

    “… For some substances, it is important to think of the human or animal body as being made up of several parts, each with their own affinity for the substance, and each part with a different biological half-life. Attempts to remove a substance from the whole organism may have the effect of increasing the burden present in one part of the organism.”

    The denial guys use “half life” to pretend the excess CO2 in the atmosphere from fossil fuel burned will go away fast and predictably. That’s not true.

    The CO2 experiment, in progress, is a very fast overdose. We’ll see what happens to vital subsystems (or to subsystems that like to think of themselves as vital because, er, sapient).

    Comment by Hank Roberts — 9 Jan 2008 @ 11:21 AM

  127. Re #123 Michael Smith: About the median, yes I see that too. I get, without Excel, by averaging the two values straddling -1.0:

    Quaas and Boucher 2005 (control): -0.90
    Chen and Penner 2005 (UM_3): -1.07

    yielding a median of -0.985.

    The median of only the last 20 values isn’t it either: -0.81.

    As for the 5% – 95% confidence interval, for a normal distribution this corresponds to +/- 1.65 sigma, not 2 sigma — or 1.96 sigma, which is for two-sided 95% significance, i.e., 2.5% – 97.5% :-)

    Anyway, I would be surprised if this data were actually normally distributed… one way to get at -0.3 to -1.8 is to remove the bottom 5% of the data — in practice, Chuang et al 2002 — and the top 5% — Dufresne et al 2005 –, after which the smallest and largest values are

    Chen and Penner 2005 (UM_6) -1.79 (rounded -1.8)
    Quaas and Boucher 2005 (MODIS) -0.3

    which is what the report states, and does not assume normality. It is slightly conservative in that for 28 data sources, 5% > one data source.

    Comment by Martin Vermeer — 9 Jan 2008 @ 11:26 AM

  128. Hi, I know this is quite a ways down this comment thread, and a little off-topic, but I was hoping someone could answer a question that I heard from a sceptic who claims to be very knowledgeable about modelling and pooh-poohs the IPCC AR4.

    I’ll just cut and paste what he said. He’s not a native English speaker, so please be patient with his sometimes clumsy expression:

    As I have pointed out in my previous message, that the members of the public tend to follow the simplistic view of the IPCC, where in reality the simplistic models quoted in the IPCC are inefficient. The most inefficient of them all the the modeling of climate feedback systems. Again, if I had to make a claim, then I must point to the source which is shown below (see link), where this workshop was a NASA sponsored one, and they (about 30 of them) wanted to address the shortfall of modeling climate feedback systems. Shortfall means misleading, unless one had to persist in accepting that the model inefficiencies are not misleading. Such a scientist must be living in a dreamland if he/she had to keep using inefficient models.

    This workshop was chaired by Dr. William Rossow of NASA , who had published his peer review work on the subject of non-linear coupled feed-back climate systems. I had made a few email exchanges with Dr. Rossow in the past, regarding his paper on the subject, in which I have read.

    Dr. Rossow, was an IPCC author in 2001, but his report on feedback from 2001 is still unchanged in 2007, since there has been slow progress in the modeling of the most complex subject of them all in climate modeling domain. If someone is close to solving climate feedback systems, then we’re looking at getting closer to understanding the big question? Is human responsible or not?


    I have said in the past […] that there is no single model in the whole IPCC report that nailed down CO2 as the driver (forcing) and this is fact and not perception, unless you can point me out to a model where CO2 is included as the driver function (forcing).

    Does this guy have a point, or is he simply waving his hands to dazzle people and distract attention? Or (alternatively), is he cherry picking some uncertainties and exaggerating them?

    I appreciate any response from modellers. Or lack of response; my feelings won’t be hurt ^^

    Comment by Nigel Aimes — 9 Jan 2008 @ 12:03 PM

  129. I have an off-topic question I hope someone can clear up for me. I’m writing RCMs again (or attempting to do so), and my latest one handles everything in bands. To find out how much a (homogeneous) layer of atmosphere radiates, I’m using the following code:

    fraction = D(hi[b], LT[L]) – D(lo[b], LT[L])
    blackbody = aband[L, b] * sigma * LT[L] ^ 4.0

    RadiatedUp[L, b] = fraction * blackbody
    RadiatedDown[L, b] = RadiatedUp[L, b]

    I’m getting screwy results, and I think the problem may lie in how I’m setting these variables. The D function gives the amount of the electromagnetic spectrum a body radiates, from zero wavelength to lambda, by the Planck function. So the algorithm I’m using is essentially

    radiated amount = (amount that would be radiated by a black body) x (absorptivity/emissivity in the band) x (fraction of radiation emitted in that band.)

    But it strikes me that with different values of a/e in each band, the fractions are no longer the same as you’d get with a pure Planck distribution. Is there some way to account for this that I’m missing? I’d appreciate any help.


    Comment by Barton Paul Levenson — 9 Jan 2008 @ 12:13 PM

  130. Nigel Aimes,
    I am not a climate scientist–jut a physicist, but if your skeptic friend were waving his hands anymore, he would levitate. “Inefficient” is not an word a knowledgeable critic would apply to the models.

    Comment by Ray Ladbury — 9 Jan 2008 @ 3:00 PM

  131. RE #126 Hank Roberts — 9 January 2008 @ 11:21 AM:

    Thanks for replying. I guess the analogy I was trying to make was more on the mathematical/rate constant end. I’ll see if I can explain myself a little better.

    The relatively short “half-lives” that get quoted seem to me to describe distribution of CO2 to biological systems (or oceans, I guess – why not a two compartment model. LOL.) – but distributed CO2 really doesn’t really go away. The real “elimination” is the sequestering. Of course, when CO2 is continually added to the system “half-life” becomes less important. Obviously we’re adding CO2 faster than it can be eliminated, or else levels would not be rising. Anyway, just a little diversion from this medical researcher, but when I see the smokestack, carbon cycle and rock pictures, with arrows, that’s what comes to mind for me.

    Comment by Deech56 — 9 Jan 2008 @ 5:20 PM

  132. Re: #87, thanks Hank – I vaguely thought I had seen that graph before. The article is a bit longer and more technical than I had in mind, but still very good.

    Comment by Dylan — 9 Jan 2008 @ 5:29 PM

  133. Nigel Aimes (128) — The physics of carbon dioxide as a global warming (so-called greenhouse) gas is well understood. For example, in the Science section of the sidebar, the first link is to the Discovery of Global Warming web pages. One section is devoted to Carbon dioxide as a Greenhouse Gas.

    No computer models are necessary to explicate this fundamental fact.
    Your correspondent is levitating on the light gas he is emiting.

    Comment by David B. Benson — 9 Jan 2008 @ 5:50 PM

  134. Nigel, would the unnamed person you’re quoting, who points to have looked for subsequent reports and cites to know what’s changed in this work on his own, do you think?

    If so, you could ask him what’s new, since that’s old.

    We can do the ‘homework help’ searching — I do see that Dr. Rossow has a lot of publications if you look for his name +NASA with Google Scholar for recent years. I didn’t do anything serious about checking forward from that old report to see what’s happened in a systematic way, just glanced at a few searches.

    Comment by Hank Roberts — 9 Jan 2008 @ 6:30 PM

  135. I know its off topic but as it hasn’t been mentioned, Bert Bolin passed away last week on the 30th December. He was a pioneer in the research and recognition of the issue of climate change, as well as the IPPC chairman from 1988-1997. Here are a few obituary links:,,2237392,00.html

    Comment by jim — 9 Jan 2008 @ 6:45 PM

  136. #15 Aaron Lewis points to which coincidentally also points to an article of interest to those asking about biosphere sequestration:

    Shilong Piao, Philippe Ciais, Pierre Friedlingstein, Philippe Peylin, Markus Reichstein, Sebastiaan Luyssaert, Hank Margolis, Jingyun Fang, Alan Barr, Anping Chen, Achim Grelle, David Y. Hollinger, Tuomas Laurila, Anders Lindroth, Andrew D. Richardson & Timo Vesala. Net carbon dioxide losses of northern ecosystems in response to autumn warming, Nature 451, 49-52(3 January 2008)

    For those who don’t have a Nature subscription:

    Short summary: biosphere sequestration is on the way down, with northern autumn warming more than compensating for increased spring growth in terms of CO_2 absorption.

    This whole discussion, important though it may be, left me with a bit of a feeling of unreality. The odd loosely worded conclusion in Nature is a minor problem compared with the truly horrendous stuff being published elsewhere (blogs, obviously biased journals, newspaper articles, financial press), much of which is very easy for me to debunk with only undergrad physics and a computer science academic background. Yet this stuff gets equal weight in the popular conception because most people don’t read Science, Nature, etc.

    The depressing thing is in the process of debunking this stuff, I would really like to find hard evidence that things aren’t as bad as reported (taking on Exxon-Mobil doesn’t strike me as a soft target), but everything I find that is outside the IPCC “consensus” and not easy to debunk actually makes things worse. (Faster than expected sea level rise, slower CO_2 environmental sequestration, evidence of CO_2 involvement in mass extinction events …)

    Keep up the good work, we have a planet to save…

    Comment by Philip Machanick — 10 Jan 2008 @ 6:30 AM

  137. Re 130.
    I think there are some very knowledgeable critics that are saying, in fact, the models are “inefficient.” I for one, think that “Python” ( would be a better work environment.

    I submitted card decks of Fortran programs to the NCAR computer in 1965. In those days, Fortran was a cutting edge technology. Now it is a legacy. We have invested so much in these models, that we are afraid to move to a new platform. However, reduced maintenance costs, improved flexibility, and reduced capital costs in the future make moving to a work environment such as Python a smart policy. Not an easy policy. There would be a lot of folks scrambling up Python’s steep learning curves. Then, they would have to rebuild the models. That would be a serious capital investment. However, then we would have models made for faster, better, cheaper climate science.

    Will it happen? Yes! There will be a global warming “surprise event,” and then policy makers will get serious about giving climate studies the resources it needs.

    [Response: Actually, Python has a very gentle learning curve. That’s why I’ve adopted it for most of my teaching. The computational exercises for my ClimateBook are built around Python (follow the link from, and most of my own modelling has been done using Python for the past 5 or 6 years. That includes the Titan model Jonathan Mitchell and I wrote about in PNAS. Usually to get performance, Python, like all interpreted languages, needs to be supplemented by compiled code in Fortran or c. However, with Python it’s easy to build new Python commands from compiled code. We’ve even gotten a Python parallel ocean model running. I absolutely agree that Python is the right platform. It’s not the learning curve so much as the fact that physical scientists are uncomfortable with the object-oriented way of doing things, and also the inertia behind Fortran. And also, now that they have Fortran90, they think there’s really no need to go beyond Fortran. I think Fortran90 is a real impediment to progress, especially since it doesn’t inter-operate well with other languages or environments. I’m working hard to change that, one grad student and one postdoc at a time.

    However, none of this has much bearing on the “criticism” originally levelled against models. Fortran is quite “efficient” in the sense of numerical performance. If it can be considered “inefficient” it is inefficient with regard to allowing flexibility in model design. That’s a real issue for the future, but that hardly affects the extent to which one can make use of or trust the existing climate simulations. It would be fair to say that debugging would be a lot easier if models were built on a platform like Python, but it is possible to write clean, maintainable code in Fortran (many modelling groups do so), and there are enough physical cross checks on full models and model components to assure that significant bugs get found. –raypierre]

    Comment by Aaron Lewis — 10 Jan 2008 @ 2:33 PM

  138. I don’t know, I’m getting a heck of a lot of mileage out of Fortran-95, and for us non-pros, there are free compilers for it out there. And I’ve never much cared for the object-oriented stuff — speaking as someone with 15 years of professional computer programming experience, that is. Nyaah.

    Comment by Barton Paul Levenson — 10 Jan 2008 @ 3:11 PM

  139. Aaron Lewis, Read what I wrote as it applies to the comment by our denialist. He is trying to cast doubt on the conclusions of the models, and “inefficiency” would merely prolong the time and increase the resources for calculation, not invalidate the conclusions. This is a guy who took maybe one computer science class in college and is trying to pass himself off as an expert. The only thing he still remembers from that class is that efficiency is good, so therefore since climate change in his eyes is a product of Satan and all his minions, climate models must be inefficient. His screed reads like technobabble from an episode of CSI–he’s probably even pronouncing his lines phonetically.

    Comment by Ray Ladbury — 10 Jan 2008 @ 4:31 PM

  140. Does anybody know about this site ( ) ? I have seen other environmental sites with carbon calculators like yahoo and tree huggers, but I am wondering what the deal with is? I saw they also published a list last month of the top ten greenest cities ( ). Does anyone know if this site is better than the others? Fill me in!

    I took their carbon foot print test and it was pretty interesting, they said that I put out 4.5 tons of carbon, does anyone know about any other tests?

    Comment by A F — 10 Jan 2008 @ 6:49 PM

  141. >earthlab
    Never heard of them. _Scary_ jargon. They specialize in “reverse research” and have a full page of marketing jargon:

    ” … EarthLab is the leading climate crisis community and multi-platform media brand … ”
    ” … providing unsurpassed real-time data collection from consumers worldwide.”

    So I looked up “reverse research” and — I sure hope this is not what they mean:

    “After either writing a paper based on things you already know or after copying a paper without bibliography, reverse research is the process of searching for books and websites to include for one’s works cited page. ….”

    The bios of the people sound reasonable. But it sounds like they’re being used for some sell-the-customers-to-the-businesses marketing.

    I hope I’m wrong. Don’t see how their nonprofit status fits with the jargon on the website at all, at all.

    I’m not cynical enough yet.

    Comment by Hank Roberts — 10 Jan 2008 @ 7:32 PM

  142. >
    Well, I’d say — look for a privacy policy on their site. I couldn’t find one, in a few minutes’ searching.
    If they aren’t asking you for info and reselling it, then they look to have a decent program. But only if they’re not using what they learn from you for marketing.

    In my sole amateur opinion of course.

    Comment by Hank Roberts — 10 Jan 2008 @ 7:34 PM

  143. raypierre (inline to 137) wrote:

    I absolutely agree that Python is the right platform. It’s not the learning curve so much as the fact that physical scientists are uncomfortable with the object-oriented way of doing things, and also the inertia behind Fortran. And also, now that they have Fortran90, they think there’s really no need to go beyond Fortran. I think Fortran90 is a real impediment to progress, especially since it doesn’t inter-operate well with other languages or environments. I’m working hard to change that, one grad student and one postdoc at a time.

    I suspect the very thought of it might give you nightmares, but…


    Fortran for .NET allows you to create applications for the Microsoft .NET Framework. Lahey and Fujitsu have combined advanced compiler technology with support for Forms designers and Web Services to enable Fortran organizations to develop .NET applications with Fortran as easily as with other Microsoft .NET languages. Fortran for .NET consists of a Fortran compiler and associated tools designed to help you create applications that run in the .NET Framework.

    Fortran for .NET Language System


    Python for .NET is a package that gives Python programmers nearly seamless integration with the .NET Common Language Runtime (CLR) and provides a powerful application scripting tool for .NET developers. Using this package you can script .NET applications or build entire applications in Python, using .NET services and components written in any language that targets the CLR (Managed C++, C#, VB, JScript).

    Python for .NET


    IronPython is a new implementation of the Python programming language running on .NET. It supports an interactive console with fully dynamic compilation. It is well integrated with the rest of the .NET Framework and makes all .NET libraries easily available to Python programmers, while maintaining full compatibility with the Python language.

    IronPython – Home

    Wouldn’t matter what languages they were programming in as long as it was all in the DotNet framework. A Fortran.Net exe could use a Python.Net DLL along with a C# custom control and what-have-you just as if they were all written in the same language since it all pre-compiles to the same pseudo-machine Intermediate Language. But I’m not suggesting anything. Just wanted to let you know that its out there – assuming you didn’t know already.

    Comment by Timothy Chase — 10 Jan 2008 @ 9:42 PM

  144. Ray, David B, & Hank – Thanks for your responses. This guy is very aggressive in the way he discounts anyone else having the relevant expertise (which I find irritating) unless they can answer his pop quizzes. And, while I thought this contention of his was way off-base:

    I have said in the past […] that there is no single model in the whole IPCC report that nailed down CO2 as the driver (forcing) and this is fact and not perception, unless you can point me out to a model where CO2 is included as the driver function (forcing)

    I had to admit I really didn’t have the expertise to argue against it. I mean, is he on another planet here, or is it in fact true that CO2 isn’t explicitly modelled as a forcing?

    [Response: The radiative effects of CO2 are explicitly modeled in all general circulation models, as are the radiative effects of other significant greenhouse gases and other climate forcings such as aerosol effects and the effect of solar variability. Point to any GCM discussed by IPCC and you have your answer to this ignorant person. –raypierre]

    Comment by Nigel Aimes — 10 Jan 2008 @ 10:16 PM

  145. Philip Machanick (#136) wrote:

    Short summary: biosphere sequestration is on the way down, with northern autumn warming more than compensating for increased spring growth in terms of CO_2 absorption.

    The operative sentence in what you linked to seem to be:

    If future autumn warming occurs at a faster rate than in spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested.

    In otherwords, if autumn warms more quickly than spring, then the carbon sink will gradually fail to keep up with our emissions — and do so ahead of schedule. And in fact autumn is warming more quickly than spring in North America, but not in Eurasia — there it is the reverse. Checked the Nature article, and it says basically the same thing. As such, the net biosphere sink would seem to be keeping up for the time being, at least according to this story. It will be interesting though to see what happens once the Arctic sea-ice is gone. Currently there is some cooling in Siberia.

    However, another article to keep in mind regarding biosphere sequestration is:

    Knorr et al, Impact of terrestrial biosphere carbon exchanges on the anomalous CO2 increase in 2002–2003
    Geophysical Research Letters, Vol 34, L09703, doi:10.1029/2006GL029019, 2007

    Drought and forest fires are going up, at least during the hotter, drier — and this means less carbon sequestration.

    But it is worthwhile to keep in mind the fact that on the whole the sinks appear to be keeping up, with net uptake being a constant percentage of our annual emissions, at least for the time being:

    In light of Piao and colleagues’ results, and of two recent studies showing diminishing ocean sinks in the critical carbon-uptake areas of the North Atlantic and Southern Ocean, it may seem odd to consider that carbon sinks might be getting stronger. But this is exactly what the steady airborne fraction of global CO2 is telling us. The global CO2 signal is most significant for two reasons: first, it is the most robust determination of carbon uptake, because the errors in atmospheric observations and fossil-fuel emissions are very small; and second, the global CO2 signal is the one that is relevant for the radiative balance that drives global climate change.

    So, what gives? For every report of a shrinking sink, there should be even more reports of increasing sinks to satisfy the global constraint. It’s possible that we are not looking in all the right places. For example, given the high and increasing amounts of biomass productivity in the tropics, and how poorly observed they are, it would not be surprising if some of the increasing sinks were there. Indeed, some studies show increasing biomass (that is, sinks) in tropical forest plots.

    Sources, sinks and seasons
    John B. Miller
    Nature, Vol 451, 3 Jan 2008

    On the whole at least, it appears that sinks are keeping up, even though some are showing signs of weakening. For the time being.

    Comment by Timothy Chase — 10 Jan 2008 @ 11:28 PM

  146. #89 raypierre

    Just going through the latest edition of Science, and I think you may be very interested in the paper on possible ice during the Cretaceous given your comment…this will be very interesting, and I suspect will generate a lot of discussion in the paleoclimate community; it is here

    Comment by Chris Colose — 11 Jan 2008 @ 2:06 AM

  147. # 136: Some press summaries of this study are ambiguous concerning the fact that the results are based on observed behavior of the whole forest ecosystem. In addition to trees, the ecosystem includes all the undergrowth and the multitude of biological processes in the soil.

    A critical difference is that the growth (sequestration) requires light energy, whereas the decomposition of organic matter in the soil does not. Decomposition (and emission) goes on as long as suitable temperature and humidity conditions are available, even in darkness. In the northern latitudes daylight in the autumn months is very scarce, also because of generally dense cloudiness. In early December, for instance main parts of the northern conifer forests receive any light at all for about 3 hours daily. Decomposition in the soil goes on as long as the ground is not frozen, and so carbon emissions dominate.

    Another factor is that plants ability to grow is partly driven by genetic adaptation to a local climate, not just temperature, humidity and light. While in the summer there is plenty of light, suitable temperatures and water, there is also a genetic cycle that terminates growth and prepares a tree for the winter. A longer summer season has therefore a limited impact on growth.

    In intensive forestry a practical recommendation is that seed origin should not be more than 200 km north or south from an intended planting location. A southerly origin causes damage due to frost bites as the trees remain in a sensitive growth phase for too long. A northerly origin causes growth to terminate too early with respect to available climatic resources.

    Due to warming autumns and winters, there is an obvious disturbance to the equilibrium, another perhaps significant feed-back loop.

    Comment by Pekka J. Kostamo — 11 Jan 2008 @ 2:55 AM

  148. Re #143 Timothy Chase and dot-net: Weren’t religious posts banned on this forum? :-)

    Anyway, what’s wrong with Scientific Python? Some of us prefer platform independent solutions. And linking with precompiled Fortran isn’t exactly a new invention…

    Comment by Martin Vermeer — 11 Jan 2008 @ 3:20 AM

  149. Following up on my above comment on the paper involving possible glaciation during the Cretaceous, I am not very convinced yet

    On one hand, you have the paradox of sea level change on large scales over short time which we can now only explain by glacio-eustasy and this paper showing geochemistry (18O) changing like it would with large-scale glaciation, but you have high tropical SST’s and associated biomass. Glaciation could only occur in Antarctica with the paleogeography, but no clue on paleoelevation. This is where gavin needs to model and figure out what kind of elevaion might be needed to get ice :-)

    It would also be interesting to see how these recent papers on arctic amplification hold up, and see if they will hold any relevance to the Cretaceous mystery


    Comment by Chris Colose — 11 Jan 2008 @ 5:54 AM

  150. I am abit surprised by what I read here. It is unabigious that the world warmed between 1980 -2000 and that the hadley centre and other say the temperatures have been flat since 2001.

    yet you hold great store by the first period and not the later because you say 15 years is long term climatic variation and 7 years is short term weather variation!!!!

    thst’s surely silly.

    [Response: No. It’s statistics. – gavin]

    Comment by Christine Marshall — 11 Jan 2008 @ 11:52 AM

  151. Re Comment on 137

    Doing substantial GCM in Python would require pushing policy makers, managers, and scientists up the object-oriented programming/ Python learning curve. Currently, they may not actually program in FORTRAN, but FORTRAN is familiar to them. They would need to become comfortable with the new environment. Once they are up there, they will love the view. My feeling is that the best investment in climate modeling that we could make would be to spend $600,000 training managers and scientists at GISS and NCAR on Python programming. It could mostly be done online using, using materials similar to what raypierre has set up and some online tutors. A smart policy maker in the organization could make this happen very fast.

    Once all those folks get up that curve, then the time and cost to answer a question will be less. That is efficiency. Any measure of efficiency needs to include: formulating the question, writing the grant proposal, funding, writing the code, running the code, and analyzing the results to get the answer to the original question that simulated the grant proposal. With Python, a physical scientist might be able to skip the whole proposal and funding delay, build the model modifications in a long weekend, and have the answer in time for the next AGU conference. That is efficiency! Almost real time climate science. It is about the only way to deal with the data from very non-linear climate responses.

    The flexibility of FORTRAN has affected how many questions were answered for the money and time that we spent. Are we getting best value for the money that we spend on climate science? Are we answering questions fast enough? More flexible models means more questions answered.

    (Every program should writen in clean, maintainable code. Work paid for by tax dollars should be professional quality.)

    Comment by Aaron Lewis — 11 Jan 2008 @ 12:48 PM

  152. Mr. Lewis —

    Have you noticed that Python is interpreted and Fortran is compiled? That means in math-intensive calculation loops, like those used in atmosphere or climate simulations, the Fortran program will run about 20 times faster. That’s probably the main reason most scientific programming isn’t done in Python.

    If someone comes out with a native-code Python compiler, you might begin to have a case. But you’d be up against 50 years of compiler writers learning to optimize Fortran code for various processors and operating systems.

    Comment by Barton Paul Levenson — 11 Jan 2008 @ 3:51 PM

  153. Attempting to come up with a better language for future highly parallel scientific computing by choosing among existing languages designed in the past for serial general computing may work, but one can imagine at least one other probable outcome.

    Another approach underway by my former employer is to create a new language specifically designed for the purpose:

    There are undoubtedly other language development efforts underway, but this is the one of which I know. Ordinarily, I would be skeptical in the extreme about an effort to develop a language that needs to be supported by such an extensive and sophisticated infrastructure (IMSL, MPI, graphics libs, compilers, users’ groups, docs, etc.). However, whatever you think of Java, I think it’s indisputable that it came with an enormous infrastructure of at least reasonable quality and the organization that did that could do the same here.

    Comment by Mike Boucher — 12 Jan 2008 @ 4:30 PM

  154. Re: #151 vs #152:

    Barton, I have to agree with Aaron here. Sure Python is interpreted, but did you notice that SciPy is based around NumPy, containing all the primitives for numerical analysis in precompiled form?

    I have unfortunately no personal experience with Scientific Python, but I do with Octave, which has standard numerics packages linked in — as Fortran libraries ;-) So all those time consuming inner loops you worry about are (or can be) optimised by the best in compiler technology…

    Comment by Martin Vermeer — 12 Jan 2008 @ 4:56 PM

  155. > Fortress

    Searching ‘climate’ in the project’s mail archive, I see email addresses indicating they’ve attracted some climate modelers.

    Nice pointer, thanks Mike. Tamino, do you know these folks?

    Comment by Hank Roberts — 12 Jan 2008 @ 5:52 PM

  156. Martin Vermeer writes:

    [[I have unfortunately no personal experience with Scientific Python, but I do with Octave, which has standard numerics packages linked in — as Fortran libraries So all those time consuming inner loops you worry about are (or can be) optimised by the best in compiler technology…]]

    If they’re calling subroutines rather than computing in-line they’re still going to be slower.

    Comment by Barton Paul Levenson — 13 Jan 2008 @ 5:58 AM

  157. Re #156

    If they’re calling subroutines rather than computing in-line they’re still going to be slower.

    Yeah, sure… knowing what you’re doing is the working assumption here ;-)

    It’s called vectorization. I used to do this myself in a previous life, coding the inner loop of what was then a massive gravity field inversion problem in PDP-11 assembler (so now you know how old I am). Enter both vectors from Fortran, allow the assembler routine to do a dot product, and fetch the result from memory in Fortran again.

    It isn’t really any different with Python/Fortran as it was with Fortran/assembler.

    Comment by Martin Vermeer — 13 Jan 2008 @ 1:56 PM

  158. If they’re calling subroutines rather than computing in-line they’re still going to be slower.

    So you would recommend, say, that every program that needs to compute the sin of an angle do so inline rather than calling the sin() subprogram?

    Comment by dhogaza — 14 Jan 2008 @ 4:54 AM

  159. Except that Python is interpreted and Fortran is compiled, so any given line of code will be slower for Python, including subroutine calls.

    Comment by Barton Paul Levenson — 14 Jan 2008 @ 6:55 AM

  160. Speaking of noise, NOAA will calculate temperatures for you using a thermometric method you may not be familiar with:

    Comment by Lawrence Brown — 14 Jan 2008 @ 10:02 AM

  161. Re #158:

    Good example. Unlikely to make a difference where you call it from, sin(x) is going to take a while to evaluate, and inlining wouldn’t help much either. But the Chebychev polynomial doing the evaluation will be of assembler efficiency nevertheless.

    OTOH there are situations where you can efficiently evaluate a large number of different function values of the same argument x using Clenshaw summation. This applies to exp, sin/cos and, e.g., Legendre functions. You need to have a recursion relation. This often happens when doing Fourier or the like, like spherical harmonics. And FFT is again a whole story of its own. All serious languages for numerics should have these things as primitives.

    Re #159:

    At this point I usually stop arguing. I made my point and cannot do so any clearer ;-)

    Comment by Martin Vermeer — 14 Jan 2008 @ 10:48 AM

  162. Let me give an example.

    0001 do 10 i = 1, 10
    0002 v = sin(x)
    0003 v = incrediblyComplexRoutineInAssembler(v)
    0004 c = exp(-v)
    0005 continue

    Line 3 will take about the same amount of time whichever language calls it. Lines 1-2 and 4-5 may take 20 times longer. So the loop will still take about 20 times longer to execute in an interpreted language than it will in a compiled language.

    Comment by Barton Paul Levenson — 14 Jan 2008 @ 3:34 PM

  163. Re: 162, only true if the assembly language function takes roughly the same amount of time as the rest of the loop. More typically, that function would take up 19/20ths of the loop execution time, so whether the rest of the loop was in a low-level compiled language or a high-level interpretive language wouldn’t make much difference. Especially so with modern, optimising interpreters that recognise loops and pre-compile them. Further, in most real-life cases, the time-savings programmers gain from using a higher level languages allows them to concentrate on the sort of optimisations that computers don’t do well automatically: choice of algorithm, use of heuristic “hints”, better feedback so that less time is wasted running algorithms that are returning obviously incorrect results etc. etc.
    There really is very little reason these days to use such a low-level language as Fortran to write an entire application.

    Comment by Dylan — 14 Jan 2008 @ 5:17 PM

  164. Re #162: That depends on how “incredibly complex” line 3 is, doesn’t it? Already if it’s an FFT on a 1024×1024 point grid, it will dominate the CPU budget — unless your interpreter is really badly written. Not even Microsoft Basic was that bad.

    Ah, I see Dylan making the same point already.

    Comment by Martin Vermeer — 15 Jan 2008 @ 4:15 AM

  165. BPL, I made my living writing compilers from 1971 until 1999. Your blanket assumptions are wrong, starting with the declaration that “FORTRAN is a compiled language while Python is an interpreted one”.

    Comment by dhogaza — 15 Jan 2008 @ 9:55 AM

  166. Really??? Fortran isn’t compiled and Python isn’t interpreted??? What did I download from Salford Software — a Fortran compiler or a Fortran interpreter? I could have sworn a compiler produced native code which could be run directly from the operating system, while an interpreter translated code and ran it essentially one line at a time. Where am I wrong there? I hope I’m not too old to learn. I certainly don’t have your experience, as I was only a professional computer programmer from 1984 to 1992 and occasionally thereafter, and have only written a few compilers.

    Comment by Barton Paul Levenson — 15 Jan 2008 @ 11:28 AM

  167. The difference between compiled and interpreted is not all that large these days. The interesting issue in computing’s near future is “who is going to harness the power of multiple processors in an easy to use way. The current price for an 8 core Mac Pro (2 quad core 2.8 GHz xeons, 2 GB memory, 320 GB disk, etc.) is 2800 USD.

    To make that kind of power easily accessible probably needs a new language/OS combination. Stand by, we are at another pivot point in computing.

    Comment by Tim McDermott — 15 Jan 2008 @ 7:42 PM

  168. Really??? Fortran isn’t compiled and Python isn’t interpreted??? What did I download from Salford Software — a Fortran compiler or a Fortran interpreter?

    I love it when people get snarky about something they know so little about.

    Cheers. Enjoy your “expertise”!

    Comment by dhogaza — 16 Jan 2008 @ 11:02 AM

  169. Well, snarky-Barty, here’s a FORTRAN product that includes both a compiler AND an interpreter:

    Still want to argue that compilation/interpretation is an intrinsic attribute of a language itself, rather than a description of one particular implementation of a language?

    while an interpreter translated code and ran it essentially one line at a time. Where am I wrong there?

    You’re right! Bingo! Congratulations!

    However, the standard Python implementation isn’t an interpreter according to your (correct, classic) definition. It compiles Python to a virtual machine, a byte-code virtual machine to be precise. That virtual machine is interpreted but in theory one could build a computer with an instruction set that would execute the byte-code directly, as Burroughs did with its mainframes that executed an Algol virtual machine back in the late 1960s/1970s. Or Semantics (I think) did with Lisp.

    There’s at least one JIT project for Python, and another Python compiler project which compiles to a lower-level language (presumably C, like the old CFront) which would then compile to machine code.

    And pseudo-code compilers for FORTRAN – just like the standard Python compiler in principle – were not unknown back in the days of smaller, slower computers. For instance, the FORTRAN compiler for the PDP-8, compiled to a virtual machine just like the standard Python implementation does today.

    “interpreted” vs. “pseudo-code compiler” vs. “native compiler” is an attribute of the implementation, not the language.

    Now it’s true that some language-computer architecture combinations that are very difficult to write native code generators for. Note that it’s the combination, not the language itself, that makes the problem difficult.

    and have only written a few compilers.

    Yeah, sounds like it, uh-huh.

    Let’s see, a couple of other things …

    Even if the standard Python implementation was a true interpreter, it wouldn’t interpret “line by line” because statements can span lines in Python. Python is not Basic…but now I’m just being mean.

    Comment by dhogaza — 16 Jan 2008 @ 11:23 AM

  170. dhogaza, running on a virtual machine which is in turn running on a real machine is still going through an interpreter as far as I’m concerned. Intermediate code is nothing new. And yes, I’m familiar with Fortran interpreters. It doesn’t change the fact that more than 99% of Fortran development engines are native-code compilers and I don’t know of ANY native-code compilers for Python. If you’re such a genius in the field, why don’t you write one?

    I stand by the concept that Fortran is faster than Python for any functionally equivalent code, and no scientist in his right mind would run a climate simulation on an interpreted language. For a global climate model you want speed, speed, and more speed, because you may be simulating climate in 100,000 boxes every three virtual hours for a hundred virtual years. You’d have to be clinically nuts to write such a thing for an interpreted language when you could use a compiler.

    Comment by Barton Paul Levenson — 16 Jan 2008 @ 12:22 PM

  171. Would you programmers look at
    please? I’ve known Mike Boucher a long time; if he says it’s worth a look, it’s worth a look.
    12 January 2008 at 4:30 PM

    I realize coming into a religious argument between two old religions recommending a new one is fraught with whatever fraught consists of, but nevertheless, Sun’s done OK with Java and a climate programming language could be timely if it’s working out.

    There’s always
    “INTERCAL — the Language From Hell
    Like FORTRAN, INTERCAL uses line numbers which are optional and follow in no … The COME FROM statement enables INTERCAL to do away with nasty GOTO’s, …”

    Comment by Hank Roberts — 16 Jan 2008 @ 2:16 PM

  172. It’s nice to see an argument break out over programming languages. A refreshing difference from the usual.

    To get perfomance out of Python, or any interpreted language, you need to get used to writing your program in a non-loopy way. A big loop in Python, as in Matlab, will be slow. The trick is to isolate useful numerically intensive primitives, and optimize/compile those. Python already has a lot of compiled packages available, including the usual array primitives in NumPy. An advantage of Python is that it is easy to build new ones. Heck, we even turned the whole NCAR radiation code into a Python object. Once you encapsulate the Fortran in a Python object, you don’t need to look at it again until it’s time to revise the low level algorithm.

    Rodrigo’s ClimT doesn’t incorporate parallelism, but Christian Dieterich’s ocean model (soon to be re-named OMlet) runs under PyMPI. After six years, we are finally beginning to know how to do this stuff, but now the money is running out.

    Comment by raypierre — 16 Jan 2008 @ 11:14 PM

  173. Raypierre,

    Have you considered taking modeling open source? There are lots of headaches, like folks getting into flame wars about things less significant than language choice. But a well run OS project can turn out high quality code cheaply.

    And think how it would vex certain people who could no longer complain about hidden source code.

    Another side effect could be that the project could be an open tutorial on how climate models work. There is a lot of talent in the world waiting for something meaningful to do. We might even get some folks who would otherwise be taking pictures of weather stations.

    Comment by Tim McDermott — 16 Jan 2008 @ 11:56 PM

  174. Just to keep you guys up to date…last year was Australia overalls 5th hottest year on record and the HOTTEST year on record for Western Australia, Victoria and New South Wales. Some parts of Adelaide an Melbourne reguraly had temps in the low to mid forties which lasted for days at a time. Lets see what the start of the La Nina will bring and whether it can cool us down some for next summer.

    Comment by Lawrence Coleman — 17 Jan 2008 @ 3:40 AM

  175. Re #172 & 173


    Tim is calling for open source. Is the NCAR radiation code which is now a Python object available? Some of us might like to see it.

    Cheers, Alastair.

    [Response: One of the goals of my whole project was to take GCM’s open source. It was too ambitious for the amount of time and money we had, but we got partway there. The whole ClimT modelling package is available at . That includes the Python-wrapped NCAR radiation package. An older and more limited version is available for download for Mac G4 on my ClimateBook web site, but Rodrigo’s official site is the best place to go for the current stuff. ClimT actually is a whole object-oriented system with hooks for dynamics and so forth so it’s overkill if you just want the radiation. Still, not hard to use. –raypierre]

    Comment by Abbe Mac — 17 Jan 2008 @ 9:57 AM

  176. Raypierre,

    I am a long time python programmer, and know some control theory and physics. I have used python for wrapping models of much lower complexity. Do you know of any educational / simple models for me to experiment with?

    Thanks for your time!

    Comment by tsk — 17 Jan 2008 @ 1:29 PM

  177. tsk: Start with the simplest model of all, a zero-dimensional radiative equilibrium model of the Earth:

    F = (S / 4) (1 – A)

    where F is the absorbed solar flux density (in watts per square meter), S the Solar constant at Earth’s orbital distance, and A the Earth’s bolometric Bond albedo. Once you have F, it will tell you the Earth’s radiative equilibrium or “effective” temperature:

    Te = (F / sigma) ^ 0.25

    where sigma is the Stefan-Boltzmann constant.

    The next step after that: Model the atmosphere as a slab which allows sunlight to pass through, but absorbs all infrared from the ground. The ground’s solar input is F from the model above. It also gets H from the atmosphere. The ground puts out G. For energy to be conserved, F + H has to equal G. For the atmosphere, it’s receiving G, and putting out H both upward and downward — G has to equal 2 H. From that, figure out the temperature of the atmosphere and the temperature of the ground. Compare them to the results from the first model.

    For a third model, try using two slabs, both of which pass sunlight but absorb all infrared. See if you can extend it conceptually to N slabs and relate N to the ground’s temperature.

    Comment by Barton Paul Levenson — 17 Jan 2008 @ 2:32 PM

  178. Re #175

    Thanks for your response Ray.

    I will have a look at that code and see if I can use it.

    Cheers, Alastair.

    Comment by Alastair McDonald — 18 Jan 2008 @ 5:16 AM

  179. Sorry to go off topic and interject politics into RC discussions, but this NPR interview with James Hansen and Mark Bowen, author of Censoring Science: Inside the Political Attack on Dr. James Hansen and the Truth of Global Warming, might be of interest to some:

    Comment by Chuck Booth — 18 Jan 2008 @ 11:39 AM

  180. quote Quite clearly from Figure 1(d), in the autumn the whole layer can be affected by what has happened at the surface (they sort of indicate this was by transport, but it could as well be by changes in radiation terms) unquote

    Could you/anyone expand on this? I’m interested in emissivity changes of open Arctic water in particular. Have there been changes? If the emissivity were to fall, what would be the atmospheric signal?

    Lynn Vincentnathan wrote

    quote A mistake on the other side, such as overestimating the danger from GW, would not be harmful, since as we all know mitigating GW (even if it is not happening…and it is) would be of great help in saving people money and boosting the economy, without lowering living standards or productivity. Sort of a win-win-win-win situation, when you factor in better health and wealth and well-being from reducing other enviro problems to boot. unquote

    Would that this were so — there are some bizarre sequestration proposals which are quite capable of doing major damage. Letting loose a crackpot carbon-fixation scheme on the principal that it would not be harmful might well be more damaging than the disease. To buy time — if things are that urgent — I would prefer people looked at Salter and Latham’s albedo enhancement proposal. It uses salt water, windpower, costs relatively little and can be switched off in seconds.


    Comment by Julian Flood — 30 Jan 2008 @ 5:10 AM

  181. JF writes:

    [[To buy time — if things are that urgent — I would prefer people looked at Salter and Latham’s albedo enhancement proposal. It uses salt water, windpower, costs relatively little and can be switched off in seconds.]]

    On the other hand, it allows the oceans to continue getting more and more acidic. Mitigation without emission reductions is not necessarily a good idea, especially if the mitigation makes people think, and fossil fuel producers assert, that they can now take a more leisurely pace toward phasing out fossil fuels.

    Comment by Barton Paul Levenson — 30 Jan 2008 @ 11:30 AM

  182. dhogaza, running on a virtual machine which is in turn running on a real machine is still going through an interpreter as far as I’m concerned.

    And then, if you build a machine that executes the virtual machine code, the interpreter becomes a compiler, despite not a single line of code being changed.

    Now, there’s a useful distinction between compiler and interpreter.


    Nor a usual one.

    And yes, I’m familiar with Fortran interpreters. It doesn’t change the fact that more than 99% of Fortran development engines are native-code compilers

    Which means you’re aware that “compiled” vs. “interpreted” is an attribute of an implementation, not the language, but are too stubborn to admit it.

    If you’re such a genius in the field, why don’t you write one?

    Because after spending 20 years writing multi-language/multi-backend optimizing compilers I got tired of it, and decided to do other things in my life.

    But that doesn’t mean I’ve forgotten everything I learned in those 20 years.

    Comment by dhogaza — 30 Jan 2008 @ 3:23 PM

  183. dhogaza, missing the point as usual, writes:

    [[dhogaza, running on a virtual machine which is in turn running on a real machine is still going through an interpreter as far as I’m concerned.

    And then, if you build a machine that executes the virtual machine code, the interpreter becomes a compiler, despite not a single line of code being changed.]]

    And if your mother had wheels, she’d be a trolley.

    Yes, if you took out the intermediate layer, it would be a compiler. Good observation. But the fact of the intermediate layer being there is what makes it an interpreter, and that’s what makes it slower than a compiled language.

    It’s hard to believe you really don’t understand this. It just seems like more of your fighting for the sake of fighting.

    Comment by Barton Paul Levenson — 30 Jan 2008 @ 4:39 PM

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