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Gray and Muddy Thinking about Global Warming

Filed under: — group @ 26 April 2006









Gray’s grand answer to the riddle of global warming is evaporation, presumably modulated by changes in the THC. Again, Gray simply doesn’t seem to understand energy conservation. Evaporation does not create heat; it does not add any heat to the climate system or take it away. It is an energy transfer that moves heat from a moist surface (like the ocean’s) into the atmosphere. That severely constrains what evaporation changes can do to climate. In contrast, changes in CO2 concentration affect the top of atmosphere radiation budget directly, and change the rate at which the whole climate system loses energy.



By the way, Gray discounts water vapor feedback, based on what seems to be a gut feeling on weather systems, plus some unspecified analysis of the NCEP reanalysis dataset (which is completely unsuitable for studying trends in mid tropospheric water vapor); more reliable satellite based studies (e.g. Soden’s study described in A busy week for water vapor ) support a positive water vapor feedback, and even Lindzen seems to be no longer arguing against this feedback.



Concluding remarks


144 Responses to “Gray and Muddy Thinking about Global Warming”

  1. 1
    Matt says:

    My ice core graph show one deg celsius temperature oscillations on a 4-6 year period around Anarctica, starting about 50 years ago. Prior to that, temperature variations were much slighter and had 40-50 year cycles.

    Is this change an indication of a tipping point? Is it an indicator of increased storms because of increased energy? Why a five year cycle?

  2. 2
    Alan Zucker says:

    Thanks for the in-depth analysis. It is important that these arguments be exposed to the light of day.

  3. 3
    Mark A. York says:

    Great detailed work as ususal. As readers here will remember, I trotted out the example of Gray over here after sceptics I was arguing with used him as the “ultimate source” on the subject, and Gray blamed everything on Al Gore. Exposing these falsehoods is a neverending job these days. Chris Mooney is covering the conference this week and will talk about it at the LA TImes Book Festival this weekend. I’ll be there.

  4. 4
    Peter Purgalis says:

    This is a little off the subject. In 98 the average global surface temperature was, a record, and about 0.2C higher than the year before or after. It is said the record temperature was because it was an EL Nino year. Can someone give me a physical explanation why El Nino would cause record global temperatures, since global warming is due to a radiation imbalace.

    [Response: Good question. In equilibrium, global temperature is indeed directly determined by the global radiation balance. On shorter time scales, however, changes in heat storage (i.e., ocean heat uptake or release) can affect global mean temperature. During El Nino events the ocean circulation changes in such a way as to cause a large and temporary positive sea surface temperature anomaly in the tropical Pacific. -stefan]

  5. 5
    Gar Lipow says:

    Hey, talking about perturbations at the top of the atmosphere, can you explain why emissions from aircraft are worse than the same quantities of emissions from cars? I see why water vapor from an aircraft constitutes a forcing rather than a feedback; the stratosphere is dry enough to absorb the additional water, and stable enough to keep it there for some time. But why is stratospheric emission of CO2 worse than ground based emission?

    [Response: CO2 is effectively mixed throughout the full height of the atmosphere after a year or so, so I don’t think that where CO2 is emitted makes any particular difference. Reactive gases would be a different story (NOx etc.) since the chemistry of the stratosphere is significantly different to the lower atmosphere – maybe that’s what you are referring to? – gavin]

  6. 6
    llewelly says:

    Peter, the 1998 measurement that is 0.2 C higher than the trend line (and the preceding and following years that make up the trend line ) are measurements of surface temperature. As such, they do not measure the heat content of the ocean, or ocean temps below the surface.

    Warm surface waters do not end at a uniform depth all over globe. In the East Pacific, the warm surface waters are a very shallow layer on top of the deep cold waters. In the West Pacific, the warm surface waters reach deeper than anywhere else in the ocean. The extra-deep area of warm water in the West Pacific is sometimes called the Indo-Pacific Warm Pool. An El-Nino does not create heat – it redistributes heat that is already in the atmosphere-ocean system. During an El-Nino, the Indo-Pacific warm pool becomes less deep, and spreads out across the Pacific. Thus, during an El-Nino, much of the heat content of the Indo-Pacific warm pool moves from being too deep for surface measurements to detect, to being spread out on the surface of the ocean, where surface measurements can detect it.

    [Response: Nice nutshell explanation. Thanks for providing that. Note that this implies that a permanent El Nino would have very different long term effects than the present style of episodic El Nino. In a permanent El Nino, all that hot water you spread across the surface of the ocean would exchange energy with the overlying air and reach a new (presumably colder) equilibrium temperature. Besides the effect of spreading the stored warm pool water over a broader area, El Nino does other things, like reducing the exposure of cold water to the surface (affecting the ocean-atmosphere heat exchange), changing atmospheric humidity, and changing cloudiness. The latter two affect the top of atmosphere radiation budget. When I throw it all into the mix, I’m left a little confused about just why it all shakes out as a transient net warming in El Nino years. I guess the “spreading of warm water” effect dominates everything else but I don’t know how inevitable that is. –raypierre]

  7. 7
    Jan Rooth says:

    For what it’s worth, I mentioned some of Dr. Gray’s recent comments to my dad (see Fig. 4 of the Marotzke paper linked above) and his first comment was “Well, Bill Gray never was too strong on the physics. He’s more of a pattern recognition guy.”

    [Response: And that Dad, I presume, is Claes Rooth, who (I believe) is the fellow who introduced the corrected picture of the THC discussed in Marotzke’s paper. Certainly, good pattern-recognizers, like Gray, have an important role to play in science in terms of suggesting new ideas, but without the next step of rigorous formulation and testing pattern recognition can be a quick route to fooling oneself. Think of Schiaparelli and the Martian Canals. –raypierre]

  8. 8
    Gar Lipow says:

    RE: Gavin on 7. I’d heard that airplane emissions are worse than the same emissions from ground transportation. (I mean that the same emissions do more harm if they come from planes.) So this is due entirely to water vapor plus Nox? (Are there any other reactive emissions?)

  9. 9
    Gar Lipow says:

    Ok – a quick search turns up from this source (

    turns up this


    The source used is in turn is:

    [Response: That’s actually “Crutzen,” not “Crytzen.” I guess the general idea there is that commercial planes fly a little bit into the stratosphere (at least in midlatitudes), and are therefore above the region of rapid tropospheric mixing. However, even the more ponderous mixing in the lower stratosphere is pretty efficient in comparison to the time it takes to remove CO2 at the surface, so I doubt that the altitude of the source is a very significant effect for CO2. The measurements I’m aware of do show that CO2 isn’t entirely well mixed between the troposphere and lower stratosphere, but the differences are pretty subtle, and are not all that radiatively significant. In fact, the stratosphere tends to have somewhat lower CO2 than the troposphere, because the industrial CO2 released in the troposphere hasn’t all reached the stratosphere. The stratosphere is older air, and therefore has CO2 concentrations corresponding to a bygone era. –raypierre]

  10. 10
    Arun says:

    March 22, 2006, NPR Fresh Air had an interview with Tim Flannery.
    My blog entry for that day:



    I can vouch for the interview, but not for the science, of course.

    [Response: We had an long,long,extensive thread on climate effects of contrails in one of the other recent posts (can’t remember which). Let’s please not start that again. The basic answer with regard to the post 9/11 data is that it’s really hard to say anything conclusive on the basis of such a short period of data. –raypierre]

  11. 11
    joel Hammer says:

    As usual, anybody who dissents is not only wrong, but wrong in every possible way. Just really awful people and awful scientists, when they are not actually corrupt.

    This doesn’t really sound like a scientific debate.

    BTW, the ozone hole over Antarctica is not getting any smaller, despite decreasing amount of chlorohydrocarbons. Not to worry. The theory can’t be wrong. So, now they are beginning to suggest global warming, by cooling the stratosphere, is making the ozone hole bigger.

    The imagination of such climatologists is matched only by their intolerance for dissenting views.

    [Response: Seriously considering dissenting views does not extend to accepting scientifically incorrect arguments. I suppose if somebody came along saying the motion of the Earth in its orbit was caused by directional phlogiston emission, you’d criticize me if I pointed out the inconsistencies in that viewpoint. This is indeed entirely a debate about science, and “views” are irrelevant. If you think there’s something wrong with our critique of Gray’s science, please speak up. –raypierre]

  12. 12
    raypierre says:

    By the way, comment #4 by Peter Purgalis is not at all off-topic. The El Nino example is quite pertinent to the THC related issues discussed in the article. El Nino can affect the global mean temperature through its influence on the surface budget, so why not the THC? In fact, the THC can influence the global mean temperature — either through nonlinearity like sea ice or clouds which can give you an effect on the mean even in steady state, or through transient effects which allow you to tap more deep cold water (for a while) and bring it to the surface. It’s not that the THC can’t affect global mean temperature — it does, in Vellinga and Wood’s experiment (in the article above I attributed the effect mainly to nonlinearities, but under further consideration I think maybe transience is also a big part of it). It’s that the sign of the THC effect on temperature is opposite to what Gray assumes, and the pattern is nothing like the observed 20th century warming pattern. Gray’s old picture (warming due to a speedup of THC), even if not supported by data on the THC, at least had the virtue that speedup of the THC would give you some warming in the Atlantic. It still wouldn’t match the observed pattern of warming, which extends to the Southern Hemisphere and also to the Pacific, and which involves more warming over land than ocean.

  13. 13
    pat neuman says:

    Instead of Gray and Muddy Thinking about Global Warming,

    this is Arrogant and muddy thinking about evaporation, probabilities and climate change

    … “With probabilities, you don’t say 100 percent,” said Mike Lukes,
    a weather service hydrologist in Grand Forks. “But 98, 99 percent, it’s going to hit a record according to the model output.”

    In March, the weather service estimated the chance of the lake hitting a record at only 20 percent. Lukes said the new outlook is not due to any unexpected precipitation in the Devils Lake basin but rather the result of changes to evaporation estimates. …

    Devils Lake headed for record, Grand Forks Herald

  14. 14
    Joel Shore says:

    Re #11 (joel Hammer): I don’t understand your complaints here at all. It certainly sounds like this RC post discusses the science of the subject. If you want an example of how not to start a scientific debate, you might look at Gray’s paper itself, which opens with a quote from a U.S. senator who most intelligent people, especially scientists, consider an embarrassment to the institution, that basically calls a whole well-established theory of science a “hoax”. And, it closes with a quote that speaks highly of a book that Gray himself characterizes as saying that global warming is a “conspiracy”!

    That is hardly the way to inspire an intelligent scientific debate. And, certainly if you are going to open and close a paper suggesting that most scientists in the field are involved in some massive hoax or conspiracy, you damn well better make sure that the science you present in between is rigorous and well-thought out. Gray’s clearly is not. I think the RC folks were frankly very polite given the tone that Gray set!

    There’s nothing wrong with writing a paper questioning the conventional wisdom in some field. My PhD thesis did this (albeit at a much less grand level). But, my advisor and I did it politely, not insultingly, and we made damn sure that we backed up our science as best as we possibly could.

  15. 15
    pat neuman says:

    re 14. 13.

    Re tone set, officials at NWS NCRFC in Chanhassen MN must have changed the evaporation parameters for Devils Lake modeling after they threw me out. Now, realizing their mistake, they must have changed them back the way I had em. I was wondering when they’d get around to doing that, seeing what was happening to the inflow from the USGS webpage and what they had out at NWS for Devils Lake earlier this year.

  16. 16
    Graham Jackson says:

    Aircraft put almost as much water vapour into the stratosphere as CO2,you appear to be neglecting this.
    The aftermath of 9/11 cooled the night temperatures somewhat.

    [Response: Note that I was only addressing the CO2 discussion in Graedel and Crutzen Stratospheric water vapor is another matter, since the stratosphere is normally quite undersaturated, because water has a hard time getting throught the cold tropopause. –raypierre]

  17. 17
    Alan says:

    RE #11: “This doesn’t really sound like a scientific debate.”

    You do have a point, there is no reason why RC should even tackle Gray’s “papers” since the science in them has already been “busted”. What makes RC’s critique a worthwhile public service is the fact that Gray’s “papers” are passed off as part of a “scientific debate” in such a way as to convince many, many people such as yourself that, “Gray’s papers have merit but nobody is listening”.

    Gray seems to think he does not have to subject his dissenting views to the peer-review process and you seem to have accepted that stand, in fact your post vigoursly supports it. If you trully belive Gray’s “papers” have merit, and you support a true scientific debate, then petition Gray to subject his “papers” to the formal debating process, ie: peer-review. I’m sure all RC readers would like hear about any of your efforts in that area.

    BTW: “Scientific dogma” is an oxymoron. If the “put up or shut up” rule is not at the heart of your idea of a “scientific debate”, then your definition is wrong.

    [Response: Aside from the fact that it is important to critique arguments that have appeared in the public forum (whether or not ever subjected to peer review), poking holes in fallacies can serve a very useful educational purpose. Putting up a plausible sounding idea and showing why it doesn’t work is an education in how to think about systems in a physically rigorous way. That’s half the reason we felt it worthwhile to respond to Gray’s paper. –raypierre]

  18. 18

    Thank you for illuminating Gray’s view of global warming. I had thought there was a legitimate scientific debate about the role of global warming and hurricanes, but it appears that the deniers, although they are legitimate scientists, seem to have fallen in with the think tank ideologues and PR lobbyists who masquerade as scientists.

    Introducing his work with a quote from an ideologically rigorous politician, who has a vested interest in advocating for the regulatory interests of the fossil fuel industry, illustrates a political sympathy with a partisan worldview that looks out of place in a scientific document. It is an especially curious way to introduce a scientific treatise that flies in the face of the scientific consensus.

    Ending his thoughts with a quote from the American Association of Petroleum Geologists endorsing the “ring of truth” of a science fiction writer’s conspiracy theory of global warming, Gray removes any doubt about his ideological sympathies.

    A conspiracy theory of global warming is very useful, in the sense that any failure to withstand the rigors of peer review, as Emmanuel and Curry have done, could illustrate nothing more than the conspiratorial bias against dissenters. But that defense fails to convince. If Gray’s unique theory has any scientifically credible merit, I would think that any professional publication would be anxious to be the first to publish a paper overturning a well-established scientific consensus.

  19. 19
    Stefan says:

    I have met Bill Gray once at a climate conference in 1998. He seemed a pleasant elderly man, he approached me and we had a nice discussion. He described to me in very clear terms how the thermohaline ocean circulation had decreased and increased at various times during the 20th Century. I felt very embarrassed – here I was, a young scientist who had been working already for seven years on the THC, and I had never even heard of these changes – I had thought it was basically unknown how the THC had varied over the 20th Century! Obviously I had a major gap in my grasp of the scientific literature. When I returned home I immediately did an extensive literature search – and to my surprise I found no studies at all that supported the very assured claims made by Gray.

  20. 20
    Timothy says:

    Re: #10 and response. I’m puzzled by this. I thought it was well established that the effect of low clouds was to cool the climate due to reflected SW radiation, whereas high clouds [such as aircraft contrails] warmed the climate due to absorbing LW radiation from the surface and re-emiiting it at a lower temperature. Of course, their direct/instantaneous effect on the surface will be simply to block the incoming SW radiation, because the LW energy they hold in the atmosphere is at their level higher up in the atmosphere.

    So the short-term response, at the surface, would be a warming when high clouds are removed, whilst the “total climate effect” of high clouds [the radiative cloud forcing] would still be to warm the climate.

    I didn’t think this was really an issue…

    [Response: Actually, it’s more complicated than that. Low clouds always cool the climate, certainly, but high clouds have the capacity for either a net warming or a net cooling effect. The balance between the two depends on the cloud height, the particle size distribution, and the cloud water content. As you note, high clouds reduce the solar heating of the surface (always) but also reduce the infrared cooling of the sub-cloud layer (always), leading to a change in the vertical distribution of heating. This can indeed have transient effects on the surface vs. atmosphere temperature, and in addition permanent effects on precipitation. –raypierre]

  21. 21
    Eli Rabett says:

    Number 11 has interested commentators with respect to its claims of innocence, but the drive by mugging* of facts is typical of these things. The short answer is that only fools and denialists expect instant gratification, but when you do serious damage to a large system such as the atmosphere, it can take a lifetime to recover. The concentrations of CFCs (and Cl) in the stratosphere levelled off ~ 1998, and only begun to deline in the past two to four years (it is a slow decline). In light of this, an expectation of a large recovery would be cartoon like. Moreover, other things including emitting large amounts of CO2, have resulted in a colder stratosphere and thus exacerbated the situation at the poles that create the ozone holes.

    A somewhat longer explanation would include the fact that it takes an average of 5 years or so for ozone emitted at the ground to reach the stratosphere and some time after that for the CFCs to dissociate to Cl. Moreover, the Monteal Protocols were not a magic wand that turned off production of CFCs immediately everywhere in 1987, but were only a first step, followed by increasing restrictions on production, further ammendments to the protocols, more countries joining in controlling emissions, elimination first of the most harmful CFCs in favor of less harmful compounds, the production of some of which is now being eliminated, etc. You can get an idea of the current situation at (in order of how much you want to know/read),,

    *mugging of facts, saying something that is literally true in a way designed to leave a false impression. Now some will say that this spreading of such memes is just due to ignorance, others will attribute it to a failure to check on the facts by the authors, and still others may say that it is due to simple mendicity.

    [Response: Thanks for this useful review. When you say “ozone emitted at the ground,” I presume that was a typo for “CFC’s emitted at the ground.” –raypierre]

  22. 22
    Hari Seldon says:

    Im an amateur at this but regarding the hurricane season;
    How siginificant do you rate the current SST?

  23. 23
    Jon says:

    I am only an observer here, but after another article critical of someone who does not agree with RealClimate’s view, I must say that I think it is an eyebrow-raising coincidence that there appears to be a 1:1 ratio between those scientists who disagree with RC’s CC view, and those scientists who, according to RC, are wrong-headed, every single time, in nearly every instance except the most minor. What is more likely, I ask: that every scientist on the planet who has a different view than RC is wrong, or that RC makes its “mind” up a-priori, and then proceeds from that premise? This of course leads to the question of what is the real intent of this blog.

    I admit it’s a bit of a chicken and the egg problem here, in that we cannot know exactly how these editorial decisions are made, but we are now trained like monkeys to expect that if we open the RC page, there will be yet another article tearing apart any who dissent from their view. It gets predictable after a while, sort of like your old uncle who holds court at family gatherings, makes pronouncements without listening to anybody or admitting any error, and is, as agreed by all, an incorrigible old know-it-all.

    With all due respect.

    [Response: I can kind of see your point. However, there are lots of disagreements discussed here – in regard to climate sensitivity, hurricanes, aerosols, climate modelling etc. but most of these are serious discussions amongst people who are genuinely trying to come to an answer. However, much of the ‘discussion’ that occurs in the media or that are pushed by various ‘interested parties’ are not these kinds of things at all. Since we are most often asked about these more public issues, that tends to lead to a focus on the worst arguments, not the best. We certainly don’t claim to know it all, and many of our more sciencey posts include lots of descriptions of genuine uncertainties, but we do know some things, and when people use bad arguments, there is a role for us in pointing that out. I take from your comment though that you’d prefer more positive ‘what do we know’ posts – and I think I agree. – gavin]

    [Response: What I’d plead for you to do is to actually look at the scientific arguments we make, and decide whether we’re right on this basis. The “chicken and egg” problem here isn’t our editorial policy. If there’s a “chicken and egg” problem it’s this: If those who argue that climate change is not a serious problem disproportionately tend to use junk science in their arguments, then it will always look like we are routinely dissenting from contrarian views, even if we are just arguing on the basis of science. –raypierre]

  24. 24
    Grant says:

    Re: #23


    I don’t think the RC team has that attitude at all. I think what you’re observing is a sampling bias.

    One of the purposes of this site is to debunk junk science. If a scientist posits an opinion in disagreement with the concensus view (or the opinions of RC operators), and that opinion (right or wrong) is based on sound reasoning and evidence, it’s not junk science, so there’s less likelihood it’ll be the subject of a post (and when it is, it’ll be discussed rationally). On the other hand, if it’s real junk, then it’s more likely to end up being debunked.

    There’s a vast difference between contrarian views (non-science masquerading as science to negate the AGW hyposthesis) and contrary views (honest, rational disagreement). I’ve found that contrary views are always treated with respect, and the discussion is open-minded. Contrarian views are given all the respect they deserve.

    [Response: Aside from debunking bad science, another thing we try to do is help publicize and explain good science that either has gotten ignored, or which has been misunderstood by the press. Our posts on water vapor, on the observed THC slowdown, and on Venus Express are in that category. I agree that the recent run of posts has been more directed toward debunking some of the bad stuff. This is not nearly as gratifying to us as talking about the good stuff, but unfortunately sometimes it seems like there are just a lot of fires that need to be put out. –raypierre]

  25. 25
    Joel Shore says:

    Re #23: Well, when someone challenges evolutionary theory, you can pretty much expect that the AAAS [the American Association for the Advancement of Science] will weigh in against them. Does this also cause you to raise your eyebrows and doubt what AAAS has to say?

  26. 26
    Mark A. York says:

    RE #23: I vehemently disagree. This is a propaganda war and science exists on a different plain, one where objective truth exists. At least so far as we can determine. When a group of paid for shills with science degrees suddenly decide up is really down then that has to be exposed. I’m a Democrat and part time field scientist and I don’t know one conservative commenter that doesn’t go for the Gray/Lindzen et all positions. That’s the only objective they have. There really isn’t a scenario where their up is down in the real world where we measure things. They want you to believe it is.

  27. 27

    Re: 23 and follow-ups

    Certainly RealClimate picks and chooses which topics to rail on (er, sorry, set the record straight on) based upon their personal and group interests/beliefs/etc. And Bill Gray has someone that has raised their ire.

    From the RealClimate “About” page is the following:


    Far and away the biggest story to come out of the AMS tropical meteorology conference this week has been the Reuters story quoting NCAR’s Greg Holland as saying:


    Since neither Holland, nor anyone else has a shred of evidence to support this statement, (or if there has been some tally of the scientific community on this issue I certainly wasn’t asked), I would think that RealClimate might want to straighten this (mis)fact for its “interested public and journalists.” But, so far, I haven’t seen this point addressed. Instead RC has chosen to take apart Gray’s conference preprint. As there are probably at least a hundred more papers/posters given at the conference, I suppose that RC will be commenting on all of the rest of them in due course. Is it appropriate for Kerry Emanuel to use a fairly long (multi-year) smoother to compare records that of things that react on daily/weekly timescales. It is appropriate for him to use a long (10-yr) smoother to draw correspondence between two records when one is suspected of having a more step-like transitions than the other? Did RC point out that in his preprint Emanuel didn’t comment on the fact that his potential intensity calculation is also dependent on the difference between surface temperature and temperature aloft–a difference that observations show is growing but that GCMs (when forced with increasing CO2) show should be shrinking? Not so far! But perhaps we’ll see a review of Emanuel’s preprint in the days ahead.

    In response to the BBC commentary, RC could seem to be congratulated for running its piece on “How not to write a press release.” But, it was really not much more than a strawman (i.e., the press release wasn’t perfect, but the point it was making was very important.). Yet, another big topic covered by the BBC was the article of amphibian die-offs by Pound et al. RC had no comment when that article came out (to great press fanfare) nor have they commented on it subsequent to the BBC story. Clearly, the conclusions of the Pound et al. study were overreached. Yet RC remained silent. While, in their defense, no one at RC may consider themselves to be an expert on amphibians in central America, nevertheless, they are all smart individuals and recognize scientific weaknesses when they see them–and the Pounds et al. study was full of them.

    So, I agree with Comment 23. RC is not about setting the record straight on all instances when the best science isn’t being used to draw conclusions on the topic of global climate change, primarily just on those instances when it is being misused to concluded something other than they want it to conclude.

    [Response: Gee, talk about the pot calling the kettle black. Here’s a complete list of topics discussed in World Climate report going back to December: Dialing in your own climate;No News is Bad News;Solar Warming?;Global Warming Not Featured in New Hurricane Study;An Extreme View of Global Warming;Antarctic Ice: The Cold Truth;Ice Storm; A (Mis)informed Public; Hot Tip: Post Misses the Point!; Hansen Revisited; Donald Kennedy: Setting Science Back; Not As Bad As We Thought!; Jumping To Conclusions: Frogs, Global Warming and Nature (Revised) ;Proving Science Bias; Natural Warming Larger Than Thought? — And how about those ads for “Satanic Gases” and “Crumbling Consensus.” Chip, at least I thought you’d have some sense of shame left, even if Michaels doesn’t. We at least try to make use of sound scientific arguments in our discussions, even if we only have time to focus on those papers which we feel have done the most damage to the use of sound science in the public forum. On those other hundreds of papers at the tropical meteorology conference, of course we’re not going to take them all apart, because most of those people are not trotting their ideas out in front of Congress and spouting off to the newspapers. Some, like Holland, Webster, Emanuel, and Curry have indeed been very public, but their scientific ideas are well and clearly laid out in their publications and while there will no doubt be a lot of continuing back-and-forth on such a difficult subject, we have not seen that any major problems have emerged so far that would call their results into question. With regard to the frogs paper, I won’t pass judgement on it, but you’ll note that so far we have tended to steer clear of the literature on impacts of global warming, though I think that it will be something we will need to put some effort into eventually. It’s an overstatement to claim that Holland didn’t have a “shred” of evidence for his statement, since somebody as prominent as he is who has probably encountered several hundred top researchers at conferences would have a legitimate read on the sense of the field. If you’re saying there isn’t any published systematic poll, yes you’re right on that, so far as I know. I’ll leave that sort of meta-policy stuff to Pielke Jr.. I’m more interested in whether there’s any scientific basis for those saying Holland’s and Emanuel’s arguments are wrong. Certainly, Holland and company have more science on their side than Max Mayfield. –raypierre]

  28. 28
    Stephen Berg says:

    I’ve lost most of the respect I had for Dr. Gray with his inclusion of the two quotes by Inhofe and the guy from the Petroleum Geologists. I believe he’s lost all credibility with respect to the AGW-hurricanes discussion. He may still have the skill to forecast year-by-year hurricane totals, but that’s it.


    Joel, Joel, Joel. Didn’t you remember from science class that CFCs have a multiple decades-long lifespan? (60 years is what I’ve learned.) CFC emissions have been reduced (by humans at the surface) to very minimal amounts compared to the pre-Montreal Protocol era.

    However, CFCs in the stratosphere remain high, but are beginning to decrease. This continued presence of CFCs in the stratosphere is resulting in the destruction of Ozone at that level, increasing the size of the ozone hole(s).

  29. 29
    Dan Allan says:

    It is interesting how people with diametrically opposite theories somehow think they support one another. Will Gray is of course disputing the “changes in solar radiation” theory of recent warming just as much as he is disputing the CO2 explanation.

    The average observer might think these skeptical camps lend support to each other. In fact they do just the opposite.

    Moreover, why is there no outrage about the “solar radiation” hoax coming from Bill Gray, and outrage about Bill Gray’s “THC hoax” coming from solar radiation believers ?

  30. 30
    Steve Sadlov says:

    The meta issue here is our still generally lacking knowledge base regarding feedbacks.

    To put on yet another EE analogy, it is as if there are a number of resistors, capacitors and inductors of unknown values in the amplifier circuit. We don’t really know the gain function with certainty. Some claim that this circuit can go into runaway based on current inputs and circuit design, but cannot conclusively prove it, since said unknown values have yet to be unmasked. In the world of EE, there are, in fact, circuits which would incur failures of circuit elements instead of going into runaway, at maximum conceivable input stress and tuning levels. In our case, the input stress is mostly solar radiation and the tuning is the net of instantanous thermal impedence. But that net impedence is very, very complex and is not a static value. And the “amplifier” is not 100% characterized. So, there is no certainty as to the outcome.

  31. 31
    Leonard Evens says:

    Let me see if I understand the general outlines of what Gray is saying. He seems to be saying that atmospheric CO_2 build-up is not a significant factor in the observed record for the 20th century. His argument seems to be that he can explain it by changes in the THC. But, if I understand correctly, naive physics, from Arrhenius and before, suggests that increasing CO_2 (and other greenhouse gas) concentrations should lead to warming. If that is not the case, because something else explains it, then we need a physical explanation for why not.

    Now of course, the naive explanation is an oversimplification, and that is the reason why climate scientists design complex computer models. And, indeed, the computer models appear to say that increasing CO_2 concentrations should lead to warming, but they differ quantitatively from what the most naive models would predict. Their predictions seem to be in reasonable agreement with the observed record, although hardly perfect about all details.

    Presumably, Gray would argue that the models are unrelable, but, if he believes his THC arguments, he still has left a big gap in our understanding. If the models are unreliable, it is quite possible that CO_2 is more important rather than being less important. It is even possible that his THC argument, when examined carefully ends up having the wrong sign, and reduces warming. In that case, climate is more, not less, sensitive to greenhouse gas increases.

    If I understand correctly, those who argued that solar influences were the dominant cause of warming made a similar argument. They claimed they had found a mechanism which explained the great bulk of the warming, so the effect of greenouse gases must be small. But they left open the question of why that was so. It was even worse in their case because they had to explain why one kind of forcing would have an effect and another kind would not.

    If I understand correctly, Lindzen has tried to deal with this conundrum. He doesn’t believe that CO_2 increases will lead to significant warming, and he has a mechanism which might explain that. Unfortunately, if I understand correctly, his mechanism doesn’t appear to work.

    It seems to me that the difference between the consensus climate scientists and the contrarians is that they do indeed try to take into account all plausible forcings, cycles, etc. And that by itself is a reason why rational non-specialists should listen to them.

    Is that a reasonable summary?

    [Response: On the whole, I’d say it’s reasonable, except that I wouldn’t describe Arrhenius’ work as in any sense “naive.” It was a very sophisticated piece of physics, building on experiments and theory from Tyndall, Stefan and Boltzmann, with a very clever use of Langley’s observations of lunar infrared to fill in the gaps in laboratory spectroscopy and radiative transfer theory. Some of his numbers aren’t of the best, but there isn’t anything essentially wrong in his picture of why infrared opacity would warm the Earth (well, maybe a little bit, in the way he deals with the top of atmosphere energy budget). The biggest thing that the comprehensive GCM’s buy for you is that they actually compute the water vapor distribution based on fluid dynamics and thermodynamics plus some approximated effects of convection; they eliminate the necessity of ad-hoc assumptions about relative humidity. They also provide some possibility of dealing with clouds, and they provide the only reliable way of dealing with regional variations, which depend very much on fluid mechanical heat transport. However, the basic underlying mechanism leading to the warming is still very much the one that Arrhenius identified, though bringing in volcanic aerosol and anthropogenic aerosol forcing, as well as solar fluctuations, proved also important in accounting for the 20th century pattern. To add to your remark on Lindzen: Lindzen doesn’t have a quantified alternative mechanism that accounts for the observed 20th;21st century warming. What he has is a proposal for a cloud based stabilizing mechanism that, if true, would seem to imply that the Earth’s temperature couldn’t change much by any means whatsoever. The original empirical underpinnings of that theory were shaky at best, and the physics relating cloud fraction to temperature were never fleshed out. Subsequent studies published in the literature have further undermined the theory, but I don’t want to oversimplify a very complex subject by trying to discuss that evidence here. At some point I will probably do a post on it. –raypierre]

  32. 32

    Re 27:


    While I am flattered that you consider World Climate Report in the same vein as RealClimate (i.e. “the pot calling the kettle black”), I think that you and I both know (or at least I thought I knew) that RealClimate serves a different purpose than World Climate Report. World Climate Report doesn’t hide the fact that it exists to support the notion “that climate change is a largely overblown issue and that the best expectation is modest change over the next 100 years,” but I didn’t know that RealClimate had an agenda besides setting the science straight. Perhaps I am wrong about that – and that was a point also wondered at in comment #23. I guess I am not sure what “shame” I should be feeling? That I thought that RealClimate’s agenda was actually different than what it really is? If you all are advocating that anthropogenic alterations to the earth’s atmopsheric composition are presently (and will continue to do so into the future) affecting all aspects of our climate and thus should be taken very seriously (and that it is better to side on the side of too much hype than too little) than I completely understand your reactions to anything that questions that philosophy. I know you all do that by example, but I didn’t know you all actually professed to doing so. So shame on me for (pretending) to think otherwise!

    As far as Holland’s claim about the “The large bulk of the scientific community say what we are seeing [in terms of hurricane activity] now is linked directly to greenhouse gases,” I just know how that could be true. In the 2001 IPCC TAR, which I suppose is often taken to represent the “bulk of scientists” it doesn’t say anything of the sort. Sure science knowledge changes and evolves over time, but do you really think that the past two hurricane seasons supplied enough new information to have changed over the “bulk of the scientific community,” especially when many big names (with or without Bill Gray) in the field of tropical meteorology have yet to throw their support behind the idea?

    Whether or not it ultimately proves to be the case, I just don’t think at present, that the “scientific community” directly involved in hurricane/climate change investigations knows for sure that current activity is “linked directly to greenhouse gases,” so I don’t know how the bulk of the scientific community at large could possibly have made up their minds (in any useful sort of way). Without some sort of evidence to this, Holland’s remarks were out of place.

    Again, if RealClimate is an advocacy group for something other than simply “good science” on climate issues then I’ll stop adding my two cents. Because your opinions and mine differ on some issues, and you hardly need another member of the bandwagon on the issues that we do agree upon. Obviously, you are able to pursue your agenda in any way you like–after all, it is your blog. If, on the other hand, you all are primarily interested in open scientific discussions and can occasionally admit (even it you don’t fully accept them) that there exist, on some issues, valid scientific opinions that are different than you all personally hold, then I will, from time, to time, take part in the discussions, or call things to your attention. And, I might expect you all to not always to be so predictable (as noticed by Jon in Comment 23).

    But, it is not always clear to me that that is what you all are interested in. For instance, in the Gray article, RC writes “In fact, it is exceedingly difficult to directly monitor the THC, and reliable results have only recently been obtained. We have reported recently on the Decrease in Atlantic Circulation.” Yet in the Comments to that article (specifically Comment 25) Martin Visbeck (who you all describe as “an expert in this particular area of the science [on the THC]”) concluded after a thorough description of the state-of-the-science:

    “None of the data assimilation models show a strongly declining trend in the mass flux at 25N in fact many of them show a weak increase overall…

    My personal take is that this remains an open issue in oceanography and climate research. We simply have not all the tools and observing systems in place to give these numbers with confidence. One thing is clear, though, that only the combined model-data synthesis will give us robust and believable answers. This paper [Bryden et al.] unfortunately does not attempt to do that.

    If you all accept this is a valid viewpoint from an expert in the field, it is certainly not made clear in your above write-up.

    So, I apologize for being confused as to your true purpose.

    [Response: I can’t help the predictability. If there’s more junk science on your side of the fence than on ours, there’s not much I can do about that. As for the comment on the THC, I am happy that you have been able to use the links provided in our article to so quickly find diverging scientific viewpoints on a difficult subject such as THC trends. Making this possible is what we try to do, even if imperfectly. –raypierre]

  33. 33
    Mike Russell says:

    Question for site admins: Will you be fisking Marlo Lewis’ fisking of Time’s cover story?

    Scare Mongering as Journalism: A Commentary on Time’s “Special Report” on Global Warming (PDF)

    [Response: I doubt it. The number of red-herrings, strawmen and simply incorrect statements would challenge even our abilities to keep up with…. -gavin ]

  34. 34
    Stephen Berg says:

    Re: #27, “Since neither Holland, nor anyone else has a shred of evidence to support this statement,” [regarding Holland’s statement “The large bulk of the scientific community say what we are seeing now is linked directly to greenhouse gases.”]

    Chip, you’re wrong. The vast majority of climate scientists are saying exactly what Holland was saying. As for evidence, I refer you to Kerry Emanuel, Kevin Trenberth, and Judith Curry’s studies. There has been no criticism of these papers from anyone except Gray, Landsea, and a couple of others who seem stuck in their ways or have to toe the line which the Bush Administration draws.

  35. 35
    Gavin says:

    Unsurprisingly, the Holland quote is taken out of context (from ):

    “What we’re seeing right now in global climate temperature is a signature of climate change,” said Holland, a native of Australia. “The large bulk of the scientific community say what we are seeing now is linked directly to greenhouse gases.”

    So he is just talking about global temperatures, not the link to hurricanes. Don’t we have enough actual issues to discuss without making up strawmen quotes to demolish? Very poor show.

  36. 36
    Richard Ordway says:

    re. 23 “there will be yet another article tearing apart any who dissent from their view. It gets predictable after a while.”

    It is heavy to read, I agree…

    but I personally believe that it is terribly necessary to expose frauds, if they are involved in public debates on national security and national survival issues…you would have believed his snake oil without reading this post, right?

    At least now you (hopefully) have some doubt and can check his (non-evidence-based, non scientific) ideas out.

  37. 37
    Mike Russell says:


    No offense, and with all due respect to the superior brains on display, but this lay reader finds that response a bit disappointing. It seems to me that a major mission of this site is demolishing “red-herrings, strawmen and simply incorrect statements” — particularly when they concern the response to a major newsmagazine’s cover story.

    You have a chance to further the conversation and, presumably, win the day. Instead, an ad hominem dismissal?

  38. 38

    Re 35:

    OK, Gavin. On further read of the April 24th Reuters story, perhaps you are right, but it is hard to tell, because your quote omits the context from the rest of the article which is headlined “Global warming behind record 2005 storms: experts” and which extensively quotes Holland including “The hurricanes we are seeing are indeed a direct result of climate change and it’s no longer something we’ll see in the future, it’s happening now.” Admittedly, I wasn’t there, so the whole article may be out of context for all I know.

    If I have misrepresented Greg Holland’s opinions, then I apologize and stand corrected.


    [Response: For the record, I do think we need to do a post on the status of attribution of hurricane trends to global warming. It would require a lot of careful reading to do it right, and the subject is evolving rather rapidly right now, so I don’t anticipate rushing into it. It’s definitely on the to-do list. –raypierre]

  39. 39
    Dano says:

    Re 35:


    Gavin, if you take away this tactic, what do they have left? It’s more interesting than quibbling over inflated marginalia…



  40. 40
    James says:

    Re to Raypierre in #32. While this not my field they do have some articles on that site that use sources from folks that you trust. Can it all be expained away as Junk Science? (Admittedly I am only a layperson here.)

    [Response: I didn’t say “all” just “more.” Note that I’m not taking a stance here one way or another on the particular view of the soot research discussed in the post you mention. –raypierre]

    [Response: Well I will. The actual study is available at along with a pop-sci descripition of the research. Basically, it simply explores another of the forcings that we are putting into the system. Nothing in it however has any implication for the radiative forcing of CO2 and so the whole of the WCM post is a false dichotomy – it’s never just one thing or another, it is the sum total of all the elements. In other work, we have also shown that tropospheric O3 has an impact on the arctic. Indeed, if you add up the individual amounts of warming you might expect from all the positive forcings, it comes to more than we have actually seen – i.e. we can attribute more than 100% of the warming. This might seem contradictory, but you have to realise that there are cooling influences as well which counteract the warming. Single factor attributions for 20th Century climate changes are just never going to be any good, and automatically assuming that because a new factor is added into the mix that means that the already well-understood ones are somehow no longer important is ridiculous. – gavin]

  41. 41
    S Molnar says:

    I believe Gray claims that there has been no increase in the frequency of tropical storms outside the North Atlantic, while others disagree. Is there uncertainty in this? I would have thought that a fairly simple correction for improved sensing (if the time frame goes back far enough) would make it an easy question to resolve. What’s the story on this?

  42. 42
    Dano says:

    Re 37:

    Instead, an ad hominem dismissal?

    There’s no ad hom at all here.

    The…er…liberal use of ad hom at some URLs is merely a marginalization tactic, BTW [see the ‘examples’ in linky provided’].

    I, for one, don’t think that every little thing ever written by authors in the employ of conservative think-tanks deserves attention. Giving it attention by replying to it can be misconstrued by the gullible; besides, RC would have to link to it and who wants CEI to get hits so that ideology can trumpet how influential its message is?

    My view is too many of these people get attention. There is a limited number of scientists, but a seemingly unlimited number of ‘fellows’ at think-tanks to flood the zone with the same tired, recycled, obfuscatory arguments.



  43. 43
    James says:

    Re 42.

    Your opinion about people with opposing points of view is terrible. The fact that they would feel the same about you would make you angry! Whether or not the view is BS is not the point. If you suppress/dismiss oposition it means that you are not intellectually honest.


  44. 44
    James says:


    I wasn’t commenting about the study itself. I was responding to Raypierre’s assertion that the webmaster? of that site merely used junk science in his arguments. I was simply saying that this is not always the case.


    [Response: But just because a serious study is quoted by someone, it doesn’t make the context of the quote, or the use to which that quote is put, serious. In this case, a serious study was used to make a junk argument and that is why we criticise such things. – gavin]

    [Response: And anyway, I wasn’t referring at all one way or another to the nature of the studies cited on WorldClimateReport. I was suggesting that the reason our choice of topics is somewhat predictable is that junk science is far, far more often used in support of the notion that global warming is insignificant, than it is used in support of the notion that global warming is an issue that is real and could have serious repercussions –raypierre]

  45. 45
    pat neuman says:

    William M. Gray wrote … I judge our present global ocean circulation to be similar to that of the period of the early 1940s when the globe had shown great warming since 1910, and there was concern as to whether this 1910-1940 global warming would continue. … A weak global cooling began from the mid-1940s to the mid-1970s. The author projects this to be what we should expect to see in the next few decades.

    No sir, we should not expect to see weak global cooling in the next few decade. Instead, we should expect to see strong global warming. Even if we think we know history, we don’t know that history will repeat itself, especially now that we know that we are loaded up the atmosphere with greenhouse gases that we know have heated the atmosphere many times before, the latest episode being the global heating to tropical like conditions in the mid-latitudes (Colorado and Wyoming in the early Eocene, 50-55 million years ago).

  46. 46
    C. Hecker says:

    Dr. Gray’s dcoument on the subject is referred to as a “meeting paper”. I confess I don’t know precisely what this means in context, but were it a journal article, if his conclusions are based on such gross blunders as basic arithmetic errors, no self-respecting referee would even allow it to be published. Is there no comparable vetting process operable here? What happened to peer review?

    [Response: Meeting papers are not peer reviewed, except for some very light screening for topic. It wouldn’t be practical to peer-review meeting papers because the time involved would compromise the main purpose of meetings, which is to communicate current research as it happens. –raypierre]

  47. 47
    Dano says:

    RE 43:



    1. I said nothing about ‘suppress’. Why do you feel you must include that word in your argument? What are you afraid of?

    2. I said nothing about people with opposing points of view.

    I said that the same ol’ tired, recycled, obfuscatory arguments by employees of conservative think-tanks are, in effect, spam.

    Do you reply to the spam in your inbox? I thought not. You do not have the time to reply to every single e-mail from the army of Nigerian spammers seeking to share their view that your manhood needs enhancing via their product.

    Nor, in my view, do working scientists have the time to reply to every conservative think tank-generated spam piece seeking to share the view that working scientists are misleading the public about the facts.



  48. 48
    Mark A. York says:

    “My view is too many of these people get attention”

    Boy howdy. With enough play these fallacious arguments become the standard in the public mind. “Is that True?” Evans said in State of Fear. For many it is true and they become impossible to convince otherwise.

  49. 49
    Hank Roberts says:

    >43, 47
    As a reader, not one of the scientists — Amen to what Dano says. I often ask people what their sources are, who they are relying on for the assumptions they are stating, and what footnotes they’ve checked themselves and updated with new info. That’s because there’s honest questions, and their’s canned skepticism.

    The canned skepticism is written by PR agencies and left around for gullible people to pick up. Often they then bring it to scientists as “something they read somewhere” and demand an explanation. A long, thoughtful, time-draining explanation. Short answer is, ‘ask why you believe what you’re asking’ first eh?

    Worse than that, the people who don’t have any idea where their info comes from or won’t say, and won’t look up anything and come prepared to say what they found out from whom, are often not people, they’re just press releases.

    This has been true in the tobacco area, the ozone area, the pesticide area+, the chromium-6 area*, and the our-friend-the-atom area in my lifetime memory. It’s a pattern.

    If I say to you “Erin Brockovitch” will you say a spew of outdated press talking points from the industry that were arguable at least up through last November or so? Or do you do your research?

    If so you’d say oh, yeah, I noticed* that PGnE had to settle before trial because their hired ‘consultant’ got caught trying to withdraw and rewrite the published research work, to try to undermine the public health regulations.


    Thing is, you gotta look up not just what someone you thought trustworthy wrote years ago that someone you believed politically reliable said was true. Read the footnotes.

    No footnotes where you’re reading? Doubt the sources.

  50. 50
    Mark A. York says:

    Excellent illustration Hank.