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  1. 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?

    Comment by Matt — 26 Apr 2006 @ 2:08 PM

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

    Comment by Alan Zucker — 26 Apr 2006 @ 2:34 PM

  3. 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.

    Comment by Mark A. York — 26 Apr 2006 @ 4:46 PM

  4. 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]

    Comment by Peter Purgalis — 26 Apr 2006 @ 5:12 PM

  5. 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]

    Comment by Gar Lipow — 26 Apr 2006 @ 5:13 PM

  6. 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]

    Comment by llewelly — 26 Apr 2006 @ 5:38 PM

  7. 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]

    Comment by Jan Rooth — 26 Apr 2006 @ 5:44 PM

  8. 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?)

    Comment by Gar Lipow — 26 Apr 2006 @ 6:57 PM

  9. Ok – a quick search turns up from this source (

    turns up this

    >A flying jet plane spews large quantities of greenhouse gases ($CO_2$ and $NO_x$) all along its flight path in its exhausts. $CO_2$, the main constituent in the exhaust gases, is heavier than air, its density relative to that of air is 1.53, freezing point is $- 56.6^{0c}$. At the altitude where commercial jets fly, the outside air temperature varies between $-35^{0c}$ to $- 50^{0c}$, slightly warmer than the freezing point of $CO_2$. However, since the vapor pressure of $CO_2$ at $- 50^{0c}$ is 101 psig, the $CO_2$ released in jet airplane exhausts will not condense, instead it will disperse at that altitude, and may gradually descend to lower altitudes very slowly, taking several years (see page 30 in [1]). Factors contributing to the slowness of descent of these gases to lower altitudes are: the fact that the region where they are released is well above the altitude from where precipitation of water and snow to ground level takes place, and there is no vegetation to absorb $CO_2$ there, and the temperature inversion at the troposphere-stratosphere boundary

    The source used is in turn is:
    T. E. Graedel and P. J. Crytzen, Atmosphere, Climate, and Change, Scientific American Library, 1995. page 30

    [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]

    Comment by Gar Lipow — 26 Apr 2006 @ 7:04 PM

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


    After 9/11, all commercial airplanes were grounded for two days over the US, and climatologists had a unique chance to study the effect of airplane con-trails on the weather (if not climate). Well, we are told that the surface temperature rose by 2 degrees. Apparently, airplane exhaust helps seed cirrus clouds, which reflect sunlight and reduce the effect of the carbon dioxide we’ve put into the atmosphere.

    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]

    Comment by Arun — 26 Apr 2006 @ 8:24 PM

  11. 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]

    Comment by joel Hammer — 26 Apr 2006 @ 8:38 PM

  12. 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.

    Comment by raypierre — 26 Apr 2006 @ 8:59 PM

  13. 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

    Comment by pat neuman — 26 Apr 2006 @ 9:52 PM

  14. 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.

    Comment by Joel Shore — 26 Apr 2006 @ 10:07 PM

  15. 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.

    Comment by pat neuman — 26 Apr 2006 @ 10:18 PM

  16. Raypierre
    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]

    Comment by Graham Jackson — 27 Apr 2006 @ 3:29 AM

  17. 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]

    Comment by Alan — 27 Apr 2006 @ 5:42 AM

  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.

    Comment by Michael Seward — 27 Apr 2006 @ 6:52 AM

  19. 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.

    Comment by Stefan — 27 Apr 2006 @ 7:48 AM

  20. 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]

    Comment by Timothy — 27 Apr 2006 @ 7:59 AM

  21. 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]

    Comment by Eli Rabett — 27 Apr 2006 @ 9:53 AM

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

    Comment by Hari Seldon — 27 Apr 2006 @ 10:40 AM

  23. 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]

    Comment by Jon — 27 Apr 2006 @ 10:42 AM

  24. Re: #23

    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 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]

    Comment by Grant — 27 Apr 2006 @ 11:08 AM

  25. 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?

    Comment by Joel Shore — 27 Apr 2006 @ 11:29 AM

  26. 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.

    Comment by Mark A. York — 27 Apr 2006 @ 12:21 PM

  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:

    “RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists. We aim to provide a quick response to developing stories and provide the context sometimes missing in mainstream commentary. The discussion here is restricted to scientific topics and will not get involved in any political or economic implications of the science.”

    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:

    “The large bulk of the scientific community say what we are seeing now is linked directly to greenhouse gases.”

    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]

    Comment by Chip Knappenberger — 27 Apr 2006 @ 12:28 PM

  28. 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.

    As for #11, “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.”

    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).

    Comment by Stephen Berg — 27 Apr 2006 @ 12:29 PM

  29. 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 ?

    Comment by Dan Allan — 27 Apr 2006 @ 1:44 PM

  30. 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.

    Comment by Steve Sadlov — 27 Apr 2006 @ 2:16 PM

  31. 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]

    Comment by Leonard Evens — 27 Apr 2006 @ 3:47 PM

  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]

    Comment by Chip Knappenberger — 27 Apr 2006 @ 4:06 PM

  33. 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 ]

    Comment by Mike Russell — 27 Apr 2006 @ 4:54 PM

  34. 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.

    Comment by Stephen Berg — 27 Apr 2006 @ 5:04 PM

  35. 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.

    Comment by Gavin — 27 Apr 2006 @ 5:08 PM

  36. 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.

    Comment by Richard Ordway — 27 Apr 2006 @ 5:49 PM

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

    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?

    Comment by Mike Russell — 27 Apr 2006 @ 5:54 PM

  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]

    Comment by Chip Knappenberger — 27 Apr 2006 @ 6:04 PM

  39. Re 35:

    Don’t we have enough actual issues to discuss without making up strawmen quotes to demolish? Very poor show.

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



    Comment by Dano — 27 Apr 2006 @ 6:09 PM

  40. 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]

    Comment by James — 27 Apr 2006 @ 6:19 PM

  41. 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?

    Comment by S Molnar — 27 Apr 2006 @ 6:30 PM

  42. 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.



    Comment by Dano — 27 Apr 2006 @ 6:45 PM

  43. 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.


    Comment by James — 27 Apr 2006 @ 6:49 PM

  44. Gavin,

    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]

    Comment by James — 27 Apr 2006 @ 6:53 PM

  45. 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).

    Comment by pat neuman — 27 Apr 2006 @ 7:34 PM

  46. 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]

    Comment by C. Hecker — 27 Apr 2006 @ 7:37 PM

  47. RE 43:

    If you suppress/dismiss oposition it means that you are not intellectually honest.


    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.



    Comment by Dano — 27 Apr 2006 @ 7:40 PM

  48. “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.

    Comment by Mark A. York — 27 Apr 2006 @ 8:01 PM

  49. >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.

    Comment by Hank Roberts — 27 Apr 2006 @ 8:29 PM

  50. Excellent illustration Hank.

    Comment by Mark A. York — 27 Apr 2006 @ 11:37 PM

  51. The…er…liberal use of ad hom at some URLs is merely a marginalization tactic

    For the record: While I’ll certainly cop to using ad hom incorrectly, I’m not from a conservative think tank, and I’m not out to marginalize anyone. Quite the opposite. I’m a lay reader who comes to this site genuinely wanting to see refutations of bad science; I am genuinely curious about what’s happening with the environment, and I’m looking for science to sort out the spin.

    Instead, I was simply assured there was spin. Which — without the hard-science rebuttal of at least a few of that paper’s points, which I’m sure would be easy for the scientists on hand — feels rather annoyingly like spin itself.

    Comment by Mike Russell — 28 Apr 2006 @ 12:03 AM

  52. Mike, my suggestion for a work flow for understanding the things you find stated: pick a point for which the author gives a source/footnote. (That’s why the Gray doc is messy, it doesn’t have any!)

    So start with something the author bothered to document for you. Look up the footnote (Google Scholar) and for new info. Decide you have something reasonably convincing to you as a non-expert, show your work done to understand as far as you got, and ask for a scientist to help you.

    Point is the broadsides, talk pieces, puff pieces, journalism, whatever all are just full of assertions but without any cite or source there’s nothing really there to respond to, the author originally has to commit to some actual information as a basis — a footnote/cite — before people can give you the helpful discussion you are looking for.

    It’s mostly smoke and mirrors and bafflegab and bullshit, by design, to keep people confused. Read the masters’ work, and look skeptically at what’s being put forth today:

    “A demand for scientific proof is always a formula for inaction and delay and usually the first reaction of the guilty â�¦ in fact scientific proof has never been, is not and should not be the basis for political and legal action”

    An example of (private) candour from a scientist at the tobacco company BAT 1. (S J Green 1980)

    Comment by Hank Roberts — 28 Apr 2006 @ 1:19 AM

  53. re 151

    Mike Russell, you wrote — without the hard-science rebuttal of at least a few of that paper’s points, …

    William Gray wrote … I judge our present global ocean circulation to be similar to that of the period of the early 1940s …


    It would not be hard to do a rebuttal on Gray’s judgment and statement that our present state of the ocean circulation to be similar to in the early 1940s, but how much time spent would be needed to get together enough evidence to show a hard-science rebuttal? Wasted time not spent on real science has costs.

    [Response: On the point of the hard science rebuttal, that's not too difficult. We just wanted to keep the post from getting too terribly long. The fact is that we have very few ways of knowing what the THC was doing throughout the last century and Gray doesn't cite any hard science to justify his particular picture. To see some of the difficulties of trying to infer the THC state from historical oceanographic data, see . There was also a paper by Wu et al (GRL 2004) which touches on similar things. Or perhaps I'm misinterpreting the comment re 51. Was the comment asking for a rebuttal of Gray on the THC or for a hard science rebuttal of the CEI piece? --raypierre]

    Comment by pat neuman — 28 Apr 2006 @ 8:05 AM

  54. Re: #51

    I’m a lay reader who comes to this site genuinely wanting to see refutations of bad science; I am genuinely curious about what’s happening with the environment, and I’m looking for science to sort out the spin.

    I’d say that’s a nice summary of one of the important purposes of this site.

    I agree with the sentiment of many, that there’s just too much garbage being spread around for us to clean it all up. Also, the RC staff are working very hard to keep us up to date, but they have very limited time (and, I think, use it rather well).

    So I’d encourage those who post here regularly to feel free to do some of the work. If a post (like Mike’s) raises questions about something, we can help by responding. And, we should stick to the very high standards set by the RC team. Be clear, correct, and give references (and links) wherever possible. That’s much more persuasive than simply saying that a particular piece is “garbage.”

    Mike, bear in mind that there *is* a lot of trash out there, and it’s just not possible to reply to it all. Also, bear in mind that although many of us are scientists, few of us are climate scientists, so we’re not able to respond with as much expertise as those who maintain the site.

    Comment by Grant — 28 Apr 2006 @ 8:12 AM

  55. Some technical questions:

    If the THC decreases, what happens to the heat distribution from the equator to the poles? Even if there is no variation of heat inflow in the tropics, how is that redistributed (more evaporation, stronger winds due to larger temperature differences…)?

    Or is it the other way round, that (observed) changes in cloud cover result in more heat inflow in the tropics, which warms the Arctic due to more heat distributed to the poles, which results in a slow down of the THC?

    Or a combination, shifted in time, which results in a large scale cycle?

    [Response: Interesting and worthy questions. I'm not sure what "large scale cycle" you mean, since there is a lot of evidence for the THC responding to forcing changes like freshwater dumps, but little or no evidence that it can undergo spontaneous internally generated vacillations of significant amplitude. Leaving that aside, the answer to your question about the effect of THC on gradients is that the Atlantic THC is a global cell which has northward heat transport all the way from the Southern hemisphere to the N. Atlantic. In some sense, it tranpsorts heat "the wrong way" in the Southern hemisphere. As such, there isn't a clear or simple connection to what the THC does to the pole-eq temperature gradient in the NH. Since many aspects of the THC take 1000 years or more to equilibrate, what kind of response you get depends on the time scale. For fairly short-term (a few decade) shutdowns like in Vellinga and Wood, what you dominantly see is a massive cooling in the Northern Hemisphere Atlantic, more or less right to the equator. The cooling is more pronounced at high latitudes, and the meridional temperature gradient is very significantly increased in the SST, but much less so in the atmosphere, since the net change in meridional heat transport in the THC is not so very large compared to the atmospheric heat transport. What you are dominantly seeing in these short term runs is the effect of a reduction of Northward drift of warm water in the NH Atlantic, perhaps amplified by sea ice effects. I don't want to speculate about clouds and evaporation, or even changes in the wind pattern, because the possibilities are too complex to make a simple story, and I don't have enough data from Vellinga and Wood to get a handle on why things are happening and what causes what. It's an interesting research question. --raypierre]

    Comment by Ferdinand Engelbeen — 28 Apr 2006 @ 8:47 AM

  56. Re: #53 et al.

    For an interesting read about reconstructions of the THC during the past century or so, see Knight et al., (2005, A signiature of persistent natural themohaline cycles in observed climate, Geophysical Research Letters, doi:10.1029/2005GL024233). Their Figure 4c shows a reconstruction of the THC from 1880 to present which shows a strengthening from about 1920 to 1950, a sharp weakening from about 1950 to about 1970 and a strengthening again from 1970 to present. The strength in the late-1940s is similar to the present (year 2000) strength.

    For those interested, here is the complete abstract:

    Analyses of global climate from measurements dating back to the nineteenth century show an “Atlantic Multidecadal Oscillation” (AMO) as a leading large-scale pattern of multidecadal variability in surface temperature. Yet it is not possible to determine whether these fluctuations are genuinely oscillatory from the relatively short observational record alone. Using a 1400 year climate model calculation, we are able to simulate the observed pattern and amplitude of the AMO. The results imply the AMO is a genuine quasi-periodic cycle of internal climate variability persisting for many centuries, and is related to variability in the oceanic thermohaline circulation (THC). This relationship suggests we can attempt to reconstruct past THC changes, and we infer an increase in THC strength over the last 25 years. Potential predictability associated with the mode implies natural THC and AMO decreases over the next few decades independent of anthropogenic climate change.

    [Response: Chip, as you well know, the recent and past peak are only similar after the observations have been linearly detrended. Since there is no reason to believe that secular warming is linear in time, all bets are off once this has been done. This is why the authors indeed clearly state in the above abstract that "it is not possible to determine whether these fluctuations are genuinely oscillatory from the relatively short observational record alone." But this has been much discussed before on this site, and if all you're going to do is recycle old arguments, you should not expect your comments to make it through our filter (please re-read our comments policy). -mike]

    Comment by Chip Knappenberger — 28 Apr 2006 @ 9:59 AM

  57. Re #32: Chip, you say “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.”

    I find this an interesting admission on your part. While I knew that in practice this was the purpose of WCR, I thought that you guys would argue it the other way around…i.e., that you end up on the side of the idea that climate change is largely overblown just because that is the scientifically correct side in your view.

    However, am I to understand that in fact you exist just to argue that side regardless of the science? I.e., am I to think of you sort of like a defense lawyer whose job it is to defend his client even if pretty much everyone including you knows he is likely guilty (so that you cherry-pick just the scientific evidence that supports your view, for example)? Or, maybe you really think he is innocent but are not above challenging evidence that you know is probably really correct? I don’t mean to be insulting but am just trying to better understand how you and Patrick Michaels view yourselves exactly.

    Comment by Joel Shore — 28 Apr 2006 @ 10:46 AM

  58. re 56.


    If the strength of the THC in the late-1940s is similar to present, then

    Why are global temperatures higher at present than they were in the 1940s?

    Why were annual temperatures in Alaska higher in 2005 than in the late-1940s?

    Why is the Jakobshavn glacier in Greenland is now moving towards the sea at the rate of 113 feet a year instead of the normal speed of one foot a year?

    Comment by pat neuman — 28 Apr 2006 @ 10:48 AM

  59. Re #56 (Chip Knappenberger)

    I’m getting mightily confused here. The quoted abstract says that “we infer an increase in THC strength over the last 25 years,” which corresponds to Dr. Gray’s old hypothesis of a stronger THC leading to warming of the tropical Atlantic and thus to more hurricane activity. But Dr. Gray has now reversed himself and hypothesizes instead that a weaker THC is what leads to warming in the tropics.

    Furthermore, it’s hard to glean from that abstract how it is that they “infer” the past changes in THC. If it is inferred from observed climate change, then the argument becomes circular as far as I can see.

    Comment by Jan Rooth — 28 Apr 2006 @ 11:04 AM

  60. Re #57: It’s probably worth noting again that WCR is a public relations effort of the coal industry. Chip doesn’t like to talk about that.

    Comment by Steve Bloom — 28 Apr 2006 @ 2:38 PM

  61. WCR is produced here:
    Chip K. is correct, this is an ‘advocacy science’ business.

    “New Hope’s scientists are accomplished public speakers who present testimony before Congress …. Nightline, Politically Incorrect, and Crossfire and … the Los Angeles Times, Washington Post, Washington Times, the Chicago Tribune, and many others.”
    “…our team of world-class scientists can offer your company or organization New Hope for our environmental future.

    ” New Hope’s international team of research scientists, data analysts, editors, and web publishers have devised, conducted, prepared, and published important research for both the public good and for private clients.
    “World Climate Report, our bi-weekly online publication, is the nation’s leading source of breaking news concerning the science and political science of global climate change.
    “New Hope’s research scientists have published extensively in the refereed scientific literature …, and they rank among the most highly regarded climatologists in their respective fields….”

    Other info is available:
    “WCR is sponsored by the Greening Earth Society, a Western Fuels Association project founded to spread the “good news” that global warming is benficial for the planet.”

    Comment by Hank Roberts — 28 Apr 2006 @ 2:42 PM

  62. This was linked in a prior RC post, but folks interested in the details of this stuff will want to have a look at Gray’s attack on Webster et al (2005) and the Webster team’s response at . Science declined to publish Gray’s comment.

    Comment by Steve Bloom — 28 Apr 2006 @ 2:48 PM

  63. Just to note that the ever-shifting cast of fossil fuel industry front groups has shifted again, with the result that the site (I think this was the “Greening Earth Society”) listed on the Exxon Secrets site Hank linked to above no longer works. Perhaps Chip would like to update date us with a current listing of WCR personnel and funding sources/amounts.

    [Response: The post on Gray was supposed to be an invitation to discuss various aspects of the way THC and evaporation could or couldn't affect climate. Unfortunately one of the earlier posters, with a lot more push next by Chip, derailed the discussion into a bunch of accusations about the nature of RC's editorial policies and how we choose the scientific topics we discuss. It's gone on too long, and I certainly don't want this to turn into a forum for discussing where WorldClimateReport's funding comes from. That's valuable and important to discuss somewhere, but RC isn't the right place to discuss it. It's not your fault -- you didn't start this diversion, Chip did (and in a moment of weakness, I took the bait, when I shouldn't have) -- but I'm asking everybody to find some other forum to discuss such things. I'd much rather be responding to questions like Ferdinand's --raypierre]

    [Response: I second that. As much fun as this all appears to be, can I ask that the conversation move back to substantive issues? There are plenty of forums where this kind of stuff is hashed through - but there are very few where the focus is on the scientific issues themselves and maybe that's worth preserving? - gavin]

    Comment by Steve Bloom — 28 Apr 2006 @ 4:52 PM

  64. The more I dig around, the more mystified I become as to what Gray’s current thinking is regarding the THC.

    The powerpoint presentation from his recent talk at the hurricane conference in Orlando is here.

    Slide 37 shows a representation of the THC which has most of the upwelling in the north Pacific and some in the equatorial Indian Ocean. This idea is outmoded. As Toggweiler and Key explain:

    It now appears that most, if not all, the
    deep water sinking in the North Atlantic upwells
    back to the surface in the Southern
    Ocean south of the Antarctic Circumpolar
    Current. The upwelling in this case seems to
    occur within the channel of open water that
    circles the globe in the latitude band of Drake
    Passage (55-65°S). Drake Passage lies within
    the belt of mid-latitude westerlies. The flow in
    the surface Ekman layer is directed northward
    and is divergent (upwelling favorable) within
    the channel. A key dynamical factor in this
    problem is the lack of meridional barriers in
    the upper 1500 m of the Drake Passage
    channel. Without meridional barriers, there
    can be no net geostrophically balanced flow
    into the channel above 1500 m to balance the
    northward flow in the surface Ekman layer.
    This means that the winds, in driving surface
    waters northward out of the open channel, tend
    to draw up old deep water to the surface from
    depths near 1500 m.

    In the same presentation, slide 40 appears to indicate that he thinks all the upwelling is taking place in the equatorial Indian and equatorial west Pacific. He also posits a connection between the strength of this upwelling and the frequency and strength of el Nino events.

    (these are essentially the same as Figures 1 & 2 in the meeting paper cited in the original post, so apparently his thinking has not changed in the last couple of months on this misconception)

    Slide 39 shows bar graphs portraying a correlation of a weak THC with low numbers of intense Atlantic storms, and strong THC with high numbers of intense Atlantic storms. Yet as pointed out above, he now claims the opposite relationship, albeit with a “10 to 15 year lag”.

    Now I could be wrong, but as I understood his reasoning in the past, it was that a strong THC means more transport of warm water north across the equatorial Atlantic and into the main development region for Atlantic hurricanes. But clearly that would not be subject to any significant time lag. Furthermore, I can’t reconcile slide 39 with this (apparently) new concept. So it seems his thinking has changed in the last couple of months with regard to this issue.

    Comment by Jan Rooth — 28 Apr 2006 @ 5:50 PM

  65. Sorry, I posted the wrong link for the Toggweiler and Ke paper.

    Here is the correct one. (pdf)

    Comment by Jan Rooth — 28 Apr 2006 @ 6:00 PM

  66. Re #62: This pretty much answers the question I asked in #41. Thanks (and sorry I failed to notice the link in the original posting).

    Comment by S Molnar — 28 Apr 2006 @ 8:00 PM

  67. Chip,

    Gray wrote … I judge our present global ocean circulation conditions to be similar to that of the period of the early 1940s when the globe had shown great warming since 1910, …

    Can Dr. Gray tell us what caused our 1930s dust bowl? How come we didn’t have a 1990s dustbowl?

    Comment by pat neuman — 28 Apr 2006 @ 9:08 PM

  68. The most compelling language in disproving Dr Gray would be to present his faulty calculations in terms of mathematical equations. I know some cringe at them, but this universal language speaks volumes and I wonder if there can be a few examples from the text written by the RC group.

    News from NH Polar region with possible influence over coming hurricane season would be the very weak or non-existent stratospheric polar vortex over this winter just past. In contrast with 1997, when the vortex was huge, and number of tropical storms and hurricanes very few, could this lack of strong winds also be mimicked near the tropics where hurricanes develop?

    [Response: There are two excellent opportunities for exploring the physical processes discussed in the post more quantitatively. For looking at what THC might do to climate, and the changes in net VERTICAL heat flux in the ocean during THC fluctuations, you could look at the Rooth two-box model discussed in Marotzke's paper, or perhaps the related box models in Gnanadesikan's Science paper. For looking at what happens when you reduce evaporation while leaving the GHG concentration of the atmosphere fixed, the best thing is to build a simple one-column radiative-convective model with a surface energy budget. If you do that with grey gas and with an isothermal stratosphere, the equations can even be solved analytically. It's especially simple to see what's going on if you work in the optically thin limit. For those who know how to do such calculations, the most illuminating thing is to sit down and do it yourself. The whole thrust of the Climate Book I'm writing is to help people learn how to formulate such simple models when they need them to clarify basic points. --raypierre]

    Comment by wayne davidson — 29 Apr 2006 @ 2:52 AM

  69. Dr. Gray is a pattern recognizer, as has been stated above. The physical explainations for those patterns were always secondary to his work and quite subject to change in his mind. He rests his reputation on the analysis of the patterns, not on his analysis of the physics, which he correctly and often points out, is not well understood by anyone.

    Since the 1980′s Dr. Gray has been making predictions about what was going to happen with Atlantic hurricanes and what the U.S. should do about it. His predictions have come to pass and if we took his advice, we could have saved 10′s of billions of dollars in hurricane damage by increasing building codes then, instead of now.

    In this respect, Dr. Gray has adhered to the scientific method. He observed nature, recognized what was happening and made a prediction based on that recognition. The prediction proved accurate, lending authority to his methods.

    Certainly, his explaination for what has happened is based on many assumptions and some of them have been shown to be incorrect. If this discredits him, then why does it not discredit the other side, which has also made countless assumptions which are constantly tweaked and changed as more data becomes available, and could still be totally wrong?

    The bottom line is that the AGW forecasts are not supported by the actual data (meaning the observed warming falls short of even the most minimal IPCC predictions), while Dr. Gray’s forecast appears to be right on.

    The climate community has put a lot of stock in the modelling of the most complex (unpredictable) system on Earth and asked the world to make great sacrifices based on these models. At the same time, they have discounted the proven method of pattern recognition, because it does not support their claims. Until the models show a pattern of successful predictions that is at least as good as Dr. Gray’s, there will be many who are skeptical of an AGW crises; as there should be!

    Finally, since there is so much that remains unknown about global climate change, anyone who takes a stand one way or the other on the issue is an advocate, by definition. Real Climate certainly falls into that category.

    [Response: Making predictions or statements based on easily demonstrated fallacies is just not a good idea. Gray's successes in hurricance forecasting was based on statistical modelling that didn't require a physical understanding to work - this is useful stuff and will work regardless of what the underlying physics actually is. The issue of anthropogenic climate change is not like that. The science of this subject is fundamentally tied to the underlying physics and no amount of correlations and statistical modelling will be able to extrapolate what will happen in the future (since we are moving into a very clear 'no analog' situation). If we advocate anything, it is that scientific statements should be based on what is already understood by the community - it is not a statement of certainty or of infallability. - gavin]

    Comment by Jim Clarke — 30 Apr 2006 @ 10:36 AM

  70. Jim,

    The bottom line is that the AGW forecasts are not supported by the actual data (meaning the observed warming falls short of even the most minimal IPCC predictions)

    Can you elaborate please? What was predicted, what has happened?

    Comment by Coby — 30 Apr 2006 @ 12:30 PM

  71. re 69.

    Jim, being a pattern recognizer do you think Dr Gray could tell us what pattern caused our 1930s dust bowl and why that pattern hasn’t been repeated yet?

    Comment by pat neuman — 30 Apr 2006 @ 12:31 PM

  72. I can, I think. Difference is irrigation. This time, we’re tapping the Oglalla Aquifer to make up for the current drought, and it’s not quite tapped out yet.

    Comment by Hank Roberts — 30 Apr 2006 @ 1:10 PM

  73. Re #71, #72: Maybe irrigation? My understanding is that eventually border trees were planted to control the blowing dust. When farmers started cutting these down about 30 years ago, the local extension agents were strongly advised to encourage the farmers not to do that and also to replant border trees. It would seem that this has, so far, been successful.

    Comment by David B. Benson — 30 Apr 2006 @ 1:46 PM

  74. re 73. 72.

    Irrigation can’t be the reason for the low humidity and absence of significant precipitation during the dust bowl years.

    For ex, summer dewpoints at Minneapolis:
    … the minima beginning in 1924 and lasting until 1937. This stretch of lower dew points matches well with the dust bowl era when precipitation was also at a minimum.
    … What does stand out beginning in the 1990â??s is the lack of dry dew point years.

    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.

    If Gray expects to see a return to a weak cooling period like the mid-1940s to the mid-1970s, how does he explain not seeing a repeat of 1924-1937 low dewpoints? Instead, we had a string of moist humidity years in the 1990s, which may be due to the positive water vapor feedback with global warming.

    Comment by pat neuman — 30 Apr 2006 @ 2:37 PM

  75. I gathered from prior discussion, especially here:
    that conditions are known to be quite different from those of the 1950s, but that comment basically only said that more discussion will have to happen in another forum or in publications. Dr. Chelliah did say clearly that the broad general assertions that others are making with reference to his work are not correct.

    It seems to me Dr. Gray’s claiming a similarity to the 1950s that doesn’t fit the published work Dr. Chellaih coauthored. Am I misreading the details here, anyone able to clarify?

    Comment by Hank Roberts — 30 Apr 2006 @ 8:32 PM

  76. Continuing on the dust bowl topic which Gray seems to have discounted, I added a few hydrology plots to my yahoo photos website to show how severe and widespread the early-mid 1930s drought was.

    I included plots showing Mississippi River streamflow (1874-2004), Lake Michigan-Huron (1918-2005) and Devils Lake ND (1830-2006).

    Contributing drainage area for the Mississippi River is 85,600 square miles at Clinton, IA and 1,140,500 square miles at Vicksburg, MS.

    I think the Clinton, IA plot is especially interesting, showing that conditions preceding 1940s/1970s cooling was a drying trend, while condition preceding the current is a wetting trend.

    That’s the opposite direction, and I figure to be counter to what Dr. Gray the pattern recognizer would expect if cooling would return. No going to happen the way he thinks, by the patterns I see.

    Comment by pat neuman — 30 Apr 2006 @ 9:37 PM

  77. Global Warming and Hurricanes: Response to Bill Gray
    From Gray and Muddy Thinking about Global Warming Anybody who has followed press reporting on global warming, and particularly on its effects on hurricanes, has surely encountered various contrarian pronouncements by William Gray, of C…

    Trackback by StormTrack — 1 May 2006 @ 11:40 AM

  78. #76, Pat, correct argument, not only that, Dr Gray seems not to see patterns from other influences, like from the North Pacific, the great region which contributed multiple sst enhanced cyclones which contributed to the great warming which spanned Continent wide this winter past. The trouble with focusing strictly on one cycle, or oscillation is that everything is interconnected, one regions significant weather change ultimately affects many others, but the question is really which is changing which? Or rather whether the change is part and parcel driven by Global Warming. The common thread seems to be GW, everywhere you look that is the real “pattern”, or undercurrent driving climates off kilter.

    Comment by wayne davidson — 1 May 2006 @ 12:47 PM

  79. re 78. 70. Wayne, I see the global warming pattern showing up everywhere too, keeping in mind Polar Amplification (1st thread of 2006 at RC). In looking at temperature trends at NOAA Cooperative Climate stations in the U.S. the warming trends are greatest in mid-high latitudes, overnight minimums and during the winter months, which is what climate modelers have been saying would happen with global warming. In the lower latitudes, temperatures aren’t supposed to trend upward much initially, although I note in my photo plots that some climate stations in Florida and Kentucky had daily minimum temperatures in July and August of 2005 which averaged higher for that two month period than the previous 100 years of record for July-August average daily low temperatures. I suspect that may be related to higher dewpoints with global warming, not allowing the temperatures to drop as much overnight. Little or no relief during hot and humid spells.

    Comment by pat neuman — 1 May 2006 @ 3:10 PM

  80. Gray’s New Climate Science, Jigsaws and the Theory of Epicycles

    Gray’s thesis as expressed in his extended abstract and presentation at the AMS conference on Hurricanes and Tropical Meteorology conference were based on the stipulation that global warming observed during the three decades is part of a natural cycle, a succession of warming and cooling periods that has occurred before and will occur again. The principal driver of this oscillation is a modulation of the ocean thermohaline circulation (THC). In his congressional testimony Gray noted that an acceleration of the THC was responsible for the warming of the North Atlantic Ocean since 1995 and the subsequent increase in hurricane intensity and frequency. In the AMS abstract Gray relates the changes in hurricane characteristics to a slowing down of the THC although in some parts of the text a strengthening is still referred to as the responsible agent. Another basic assumption made by Gray is that there is a water vapor feedback does not occur following rather strictly Lindzen’s IRIS theory that has tended to fail close scrutiny. All subsequent arguments are manipulated to support these cornerstones of Gray’s hypothesis that there is no anthropogenically induced climate changes on the planet.
    The style of Gray’s presentation was familiar, oscillating between ridiculing everybody else’s scientific contribution and offering instead confident if not confused alternative perspectives. Global warming is dismissed because he states that scientists who find evidence for global warming were the same scientists in the 1970′s who thought that the planet was heading towards an ice age. Gray’s points were accompanied the now familiar diatribe against modelers. The climate system is far too complicated to model or even understand so that following the climate-modeling route was inherently flawed. However, it seems that the climate system is not too hard for Gray himself to understand and deconvolute as he proceeded to offer simple descriptions of how the climate system really works.
    Gray’s scientific exposition began with Broecker’s THC diagram. As best as I could follow, he argues that modulations of the subtropical high-pressure zones cause anomalies in the THC through enhanced or reduced upwelling throughout the depth of the ocean column in the Atlantic equatorial zones that simultaneously causes changes along the entire global route of Broecker’s circulation. These modulations of the THC change the surface heat flux by the same amount as might be produced by the water vapor feedback if it were included! It was also inferred that oceanographers simply did not understand the physics of the ocean and that as the THC was not modeled correctly it was the “Achilles heel” of those who propose global warming. Gray noted that oceanic observations of the THC were not necessary and that anomalies in the subtropical high-pressure belt were all that is needed to measure changes in the THC. I guess we could have saved a lot of money if WOCE had had Gray’s insight 20 years ago.
    Gray proposed a “new” thermodynamics. Climate scientists are “hamstrung” by an adherence to the Clausius-Claperyon relationship, which requires that saturated vapor pressure increase exponentially with temperature. Gray proposes that the reverse is true with saturated vapor pressure decreasing with increasing temperature so that there is less evaporation from a warmer ocean. But here emerges a problem. For his chain of arguments to work he must have evaporation being reduced as wind speeds increase. He ignores that part of the turbulent flux relationship involving wind speed and instead uses his new reverse C-C relationship. Gray is either unaware or ignores well-founded observational evidence that an increase in evaporative flux over the oceans has occurred during the last decades accompanying stronger winds!
    In summary, Gray proposes a theory of how he believes the climate system really works, one which goes against simple thermodynamical theory that has been around for centuries, theoretical calculations, results from climate models and diagnostic studies, all of which propose a consistent and coherent argument for climate change occurring from radiative changes associated with increasing greenhouse gases. Perhaps an analogous approach would be putting together a jigsaw puzzle, ignoring the picture on the box and using a hammer to force the pieces together irrespective of what the final picture finally produced.
    Following Gray’s talk, a number of questions were asked. I asked why he had changed the sign of the THC from speeding up to slowing down between the congressional testimony and his extended abstract to explain the same phenomenon? I also asked him if he was influenced by the Bryden et al article (Nature December 2005) and that was the reason he changed the sign? He stated that he had “..been through all of that many times..” and that these bits and pieces of data collected by oceanographers meant nothing. Ditto to the global increases in ocean heat content catalogued by Levitus in his recent series of articles. A second question from Greg Holland took umbrage at Gray’s depiction of modelers as doing something sly by promoting false or ill-conceived results. Holland noted that the problems of climate were important and that modelers were doing honorable work on socially relevant problems and that models provided the most powerful diagnostic and predictive tools available. Holland’s comment brought a large ovation from the audience.
    I have been keeping track of the data sets and published scientific findings that must be in error for Gray to be correct on the relationship between hurricane intensity and global warming and for everyone else to be wrong. These data include:
    - Ocean reanalysis data that shows global trends in ocean heat content (Levitus 2005 JRL, Barnett et al. 2005 Science).
    - Oceanographic section data such as collected by Bryden et al. 2005 (Nature December) indicating a slowing of the meridional overturning in the North Atlantic Ocean during the last decade.
    - Atmospheric reanalysis data that does not contain trends in vertical shear with SST increases during the last 35 years (Hoyos et al. 2006, Science April).
    - SMMI satellite data that has shown an increase in evaporation associated with increasing winds during the last few decades (e.g., Liu and Curry GRL, Mar 7, 2006).
    - Global tropical storm data (see for the satellite era (1970-2004). Valid questions have been raised on the quality of these data, however, in order for the trends noted by Webster et al. 2005 (Science, September 13) not to be significant around 150 storms would have to be incorrectly classified from 1970-1985 by either being missing from the data set or judged to be major hurricanes (category 3+4+5) when they were a lower category.
    - Surface flux data collected from the many tropical experiments (TOGA COARE, JASMINE) or the Pacific TAO array that show increases between surface latent heat flux with wind speed or warmer SST.
    - All climate system models which show any increase in global temperature associated with GH forcing.
    Overall, I am reminded of the Astronomical Epicycle Theory. The problem for early astronomers was how to keep Earth at the center of the universe and still explain the orbits of the moon, planets, stars and other celestial bodies. This was explained by inventing “epicycles” which were sets of ad hoc circular loops devised to explain why the celestial bodies made an apparent “loopback” motion when viewed from Earth. As astronomical observations continued to amass, the necessary epicycles became more and more complicated to fit a geocentric perspective. Copernicus and Kepler eventually clarified and simplified the system but not without social ramifications. Gray’s new climate science with its inventions and reinventions, is perhaps the modern day epicycle theory; one where inconvenient concepts or observations are warped to fit a higher “truth”.
    As the list of inconvenient data list gets longer, expect the theories of the new climate science to be modified. After all, the universe does rotate around Earth and there must be a way of explaining it. Have no doubt, epicycle climate theory is very malleable and ductile.

    Comment by pjw — 1 May 2006 @ 5:26 PM

  81. RE 80 (pjw);

    Plz do a proper citation or link to the piece you quote without attribution so informed readers can place in context.

    Thank you in advance.



    Comment by Dano — 1 May 2006 @ 7:28 PM

  82. Re #81: Dano, “pjw” is Peter Webster and this was his (very kind to us as this sort of information isn’t normally available in “real time”) report from the hurricane conference on the material relevant to this post. It’s not a quote of someone else’s work. Thank you, Peter.

    Comment by Steve Bloom — 1 May 2006 @ 9:07 PM

  83. Interesting quote from #80:

    “Gray noted that oceanic observations of the THC were not necessary and that anomalies in the subtropical high-pressure belt were all that is needed to measure changes in the THC. I guess we could have saved a lot of money if WOCE had had Gray’s insight 20 years ago.”

    Climate science inherently suffers from a lack of experimental opportunities (controls) so observational data collection is very critical (otherwise, what would you be comparing the model results to?). Ocean sciences rely on pretty sparse data as it is – especially in terms of depth profiles of currents and temperature. It really seems that any scientist interested in this issue would want the most accurate and comprehensive data available, and wouldn’t want to rely on more tenuous secondary associations that are influenced by many other factors. Paleoclimate studies have to rely on secondary proxies, but not by choice! This doesn’t seem like an honest argument on the part of Dr. Gray.

    Is it even clear what fraction of northern heat transport in the Atlantic is due to the THC, and which is due to wind-driven surface ocean currents, and which is due to atmospheric transport? Tim Osborn, the UK Climate Research Unit, has a nice introduction to this at Thermohaline circulation for the uninitiated. How can anyone say that oceanic observations are not necessary in studying this very complex system?

    The epicycle analogy in #80 seems accurate. The epicycle argument was supported by interests whose main goal was maintaining the notion of infallible papal authority. The ‘natural climate change theories’ are supported by entrenched economic systems that have the very short-sighted goal of preventing the adoption of government regulations that would severely limit the use of fossil fuels; the ‘scientific viewpoints’ they promote tend to be internally inconsistent and to conflict with observations; thus they largely are funnelled out to the press through industry-funded think tanks rather then through any normal peer-reviewed process. RealClimate in some sense provides ‘independent peer review’ for this brand of ‘science’ which is one reason why RC is a valuable site, regardless of what the above detractors/distracters say.

    It is worth noting that some of Gallileo’s contemporaries refused to look through his telescope for fear of sullying their minds with artificially manipulated images. Even today, those epicycle theories persist in astrological circles (that’s what ‘Mercury in retrograde’ is referring to!).

    Comment by Ike Solem — 2 May 2006 @ 12:28 AM

  84. RE 82:

    Thank you Steve. Obviously I missed something somewhere.

    Thank you Peter,



    Comment by Dano — 2 May 2006 @ 12:49 AM

  85. THC slow down.
    I surmise that when ice separates from the sea the salt concentration increases.The sea becomes denser and sinks being replaced by sea with normal salt concentration.
    If the salt concentration of the sea is reduced by dilution with fresh water then it will freeze at a higher temperature but the denser sea water will still sink.
    If the THC slows down then less heat will be transported to the Arctic.
    Both these conjectures indicate that Arctic sea ice should expand.

    [Response: Just speaking for myself, I wouldn't say that the Bryden et al paper is the last word on what the THC is doing right now. It's probably the best attempt to date, but it's a hard thing to do. But, what you are saying is correct, or would be correct if THC were the only thing affecting Arctic climate. In all simulations incorporating sea ice, the sea ice advances when the THC shuts down, and indeed the advance of sea ice is believed to be the main amplifier leading to such a large Greenland cooling. However, what we have now is the combined effect of anthropogenic greenhouse warming, plus the effect of whatever THC is doing. If Bryden is right and the THC is slowing down, then the THC slowdown is helping to offset Atlantic warming, and is thus preventing the sea ice retreat from being even larger than it is. Something similar does happen in some of the IPCC models which have a lot of THC slowdown in response to greenhouse gas increases -- the THC slowdown doesn't trigger a European ice age, but somewhat limits the N. Atlantic warming (at the expense of making some other part of the globe get even warmer). --raypierre]

    Comment by Bryn Hughes — 2 May 2006 @ 3:32 AM

  86. An interesting article was in EOS last week that looks at THC in a previous warm period. “Eocene Hyperthermal event offers insight into Greenhouse Warming” By Bowen et al. A key paragraph is…

    “One potential consequence of future global warming is a perturbation to the ocean’s thermohaline circulation, which may further change global climate. Indications that ocean circulation changes occurred during the PETM are thus of great significance. Surface ocean warming was amplified at high latitudes (as much as 9°C) relative to low latitudes (5°C), while deep-water temperatures rose by 4º-5°C globally [see Zachos et al., 2005, and references therein]. During the PETM, reduced pole-to-equator sea surface temperature gradients or changes in continental freshwater runoff may have shifted the site of deep-water formation from a Southern Ocean locus to subtropical latitudes or to high latitudes in the Northern Hemisphere [e.g., Kennett and Stott, 1991; Bice and Marotzke, 2002; Nunes and Norris, 2006], introducing warm water to the deep sea and driving methane clathrate destabilization and further greenhouse warming [Bice and Marotzke, 2002].”

    The point is the THC changed due to a significant warming, but it did not suppress high latitude warming at all. They point out that surface warming was amplified at high latitudes and deep temperatures rose to a lesser but still substantial amount. This does not agree with #85. THC is density driven, and if the air is warmer and the seawater is warmer it is true it will be tougher do drive deep water formation via cooling and salinity enhancement. However, this does not then lead to more sea ice production since other factors are driving up polar ocean temperatures.

    [Response: Very good remark. The combined effect of a THC slowdown plus accentuated greenhouse warming is very different from what you get from a THC slowdown alone, and may even be quite different from the sum of the two effects independently -- since sea ice formation and bottom water formation locations are highly nonlinear processes. --raypierre]

    Comment by Mauri Pelto — 2 May 2006 @ 9:14 AM

  87. In defense of epicycles…

    Yes, it’s a mistaken theory. But given the observational tools available to the ancients, it’s a reasonable one: it worked better than the available alternatives. When viewed as a physical construct (spheres upon spheres upon spheres) it’s nonsense, but when viewed as simply a mathematical method for calculating planetary positions, it’s quite natural — rather like a “Fourier decomposition” of planetary motions.

    Copernicus retained them in his model of the solar system, but showed that by assuming a heliocentric rather than geocentric system, far fewer epicycles were required, simplifying calculations considerably.

    It wasn’t until Kepler than a viable alternative was offered: elliptical orbits. This was not a leap of faith, but of mathematics. To my knowledge there was no ecclesiastical objection to Kepler’s idea — abandon epicycles in favor of ellipses. The objection was to the heliocentric idea.

    And I think that objection wasn’t fueled by devotion to papal infallibility, but by scriptural fundamentalism.

    [Response: I'll grab the last word on the question of the Catholic Church vs. Gallileo (hopefully a conciliatory one), but then ask that we not get any further into the admittedly interesting questions of Vatican science policy at the time of Gallileo. I merely want to emphasize that Gallileo's problems with the church do not reflect any deep-seated conflict between science and religion, the more so since the Vatican has never embraced scriptural fundamentalism. In some sense, the Vatican's earlier stance (informed much by Aquinas) in some ways was an attempt to state that there was no essential science/religion conflict. The problem was that the "resolution" was based on an Aristotelian and perhaps heliocentric geocentric view of the Universe, and papal authority was behind that. In my view, the problem came from an injudicious use of papal authority. The notion of infallible authority is indeed inimical to science, which has to be mutable and evolve in response to new data and new theories. I like to think that the Vatican has become somewhat more judicious since, in what it puts papal authority behind. It will always be hazardous to put papal authority behind the kinds of questions that are quintessentially answered by science, as opposed to those areas where theology has the most to say. Sorry for intruding these thoughts, but since we let some of the preceding discussion through I at least wanted to end on a note that avoided the implication that there was some unbridgeable gap. here. --raypierre]

    Comment by Grant — 2 May 2006 @ 10:42 AM

  88. I attended two seminars in DC yesterday – one given by Dr. Kerry Emanuel, the other by Dr. Chris Landsea, both about recent changes in tropical cyclone frequency and intensity and how they may be related to (anthropogenic) global warming.

    While there were many similarities between the presentations, there were two major points of disagreement: 1) are major hurricanes the current era (last decade or so) really stronger or more frequent than they were in the past, and 2) is the AMO a naturally occurring phenomenon.

    On the first point, Dr. Landsea suggests that changes (improvements) in observing practices over the years (including post-1970) quite possibly have led to the more frequent identification of major hurricanes and that this effect has not been adequately accounted for by the studies of Emanuel and Webster et al. Dr. Emanuel countered that he used windspeed corrections based upon Landsea’s (earlier) published recommendations (which Landsea now contends are unwise), and Dr. Webster notes (in his comment #80 above) that 150 major storms would have had to be missed or misclassified (globally) in order for his results to be much effected. Dr. Landsea gave evidence that total number of missed or misclassified storms could be significant.

    On the second point, Dr. Emanuel showed that there is a strong correlation between the 10-yr smoothed record of Northern Hemisphere temperatures and the 10-yr smoothed record of SSTs in the main development region (MDR) for tropical cyclones in the North Atlantic. He pointed to this strong correlation as evidence that the MDR temperatures are simply following the larger-scale temperature of the Northern Hemisphere (and globe for that matter) as they have responded to a combination of natural and anthropogenic forcings (GHGs and solar in the early part of the 20th century; GHGs and sulfates in the mid-part of the 20th century; and primarily GHGs since then). Dr. Landsea suggests that perhaps the circulation changes in the North Atlantic are a significant contributor to the NH temperature changes. Dr. Kerry contends that this is the tail wagging the dog, and this so-called Atlantic Multidecadal Oscialltion (AMO) is simply a statistical artifact of the large-scale temperature changes brought about primarily by anthropogenic forcings. In fact, Dr. Emanuel went as far as to say that even Mike Mann, who gave the moniker of AMO to the phenomenon, now dismisses the idea that it is a natural oscillation, and in fact, he too, believes that is only a manifestation of larger-scale temperature trends.

    However, Dr. Emanuel made no mention of the recent paper by Knight et al. that documented an AMO-like oscillation in unforced climate model runs. The authors concluded:

    Our 1400 year model simulation exhibits multidecadal climate variability with a similar pattern and amplitude to that of the AMO in observations. Together with the similarity of the simulated 70-120 year period to the observed 65 year period, and the range of periods derived from palaeodata (40-130 years) [Delworth and Mann, 2000; Gray et al., 2004], this suggests the model simulates a realistic AMO. Its presence over many centuries in the model supports the suggestion from observations and proxy data that the AMO is a genuine repeating mode of globalscale internal climate variability.

    This suggests that an AMO-like oscillation does exist (at least in some models) without anthropogenic influences.

    Honestly, I am not trying to be difficult here. Scientists have the right to change their minds (in fact they should) when faced with data and observations that run counter to their earlier understanding. Dr. Landsea apparently has done this when it comes to the appropriateness of wind speed adjustments in the early tropical cyclone record, and Dr. Mann (at least according to Dr. Emanuel) has done this when it comes to the phenomenon of the AMO. If Dr. Emanuel is correct in his characterizations of Dr. Mann’s thinking about the AMO, I think that it would do a great service to the entire community for someone at RealClimate, perhaps even Dr. Mann, to take us through the current best thinking about the origins of the AMO signal in the temperature record of the Atlantic Ocean – both the 100 or so year observed record as well as the 1400 year simulated/reconstructed record.

    It is all rather confusing that the peer-reviewed record indicates one thing, and yet the current thinking by a number of prominent scientists is for another. As I am a (somewhat) active researcher/commentator in the field of climate/hurricane relations, I find myself in a bit of a quandary… when I cite the published literature I am told that I am wrong, but I have nothing else to go on, I don’t think RC discussion are citable, are they?

    Thanks for considering an explanation.

    -Chip Knappenberger
    (primarily funded by the fossil fuel industry since 1992)
    (benefiting from fossil fuels since 1964)

    PS. As an interesting aside, Dr. Emanuel said that he is working on a theory (he did not go into details about it) that holds that intensification of North Atlantic tropical cyclones from global warming will lead to an acceleration of the THC!

    [Response: The 'new theory' isn't so new, Emanuel has published before on the potential link between tropical mixing in the ocean (in which hurricanes may play a significant role) and it's effect on the overturning. The basic idea is that the THC is a balance between polar deep water production and mixing. In models at least, the strength of the THC is positively dependent on the net amount of mixing. The link to hurricanes is intriguing, but not yet widely accepted. However, it would follow then that if hurricanes increased that that would eventually lead to an increase in THC. Pretty speculative though... - gavin]

    [Response: Kerry's Hurricane-THC link takes off from the results of the famous "Abyssal Recipes" papers by Wunsch and others, which noted that one needs to input mixing energy into the ocean in order to bring up deeper water against stable stratification and sustain a deep ocean circulation. More hurricanes could increase the vertical mixing in the tropics, allowing more cold water to upwell in the Tropics (where it only rarely does now); one of the more intriguing possibilities is that the resulting tropical mixing could help explain the low-gradient Eocene climates, by cooling the tropics while stimulating ocean circulations that transport more heat poleward. There are a lot of open questions in terms of how this would work, and given that the hurricane induced mixing wouldn't tap into the really deep water, I'm not sure I'd describe the effect as enhancing "the" THC, as opposed to stimulating a new kind of oceanic heat-transporting circulation. No question, though, it's an interesting development and is all part of the process of figuring out what a high CO2 greenhouse world would be like. --raypierre]

    [Response:Chip, some comments on your statement: "Mann, who gave the moniker of AMO to the phenomenon, now dismisses the idea that it is a natural oscillation, and in fact, he too, believes that is only a manifestation of larger-scale temperature trends." The first part is correct. I did coin the "AMO" in an interview with Richard Kerr some years ago for a news article he was doing on Delworth and Mann (2000). The term first appeared in Kerr's article. The 2nd part of your statement is not correct. I have not dismissed the idea that there is a natural multidecadal climate oscillation involving coupled ocean-atmosphere processes in the North Atlantic. Indeed, I've published a number of papers providing support for this assertion (Mann and Park, 1994;1996; 1999;Delworth et al, 2000; Knight et al, 2005). However, in almost all of these analyses, the signal is found to have very little if any amplitude at all in the tropical Atlantic (see figures 21 and 31 in the Mann and Park, 1999 (warning, 5MB!) review paper [Mann, M.E., Park, J, Oscillatory Spatiotemporal Signal Detection in Climate Studies: A Multiple-Taper Spectral Domain Approach , Advances in Geophysics, 41, 1-131, 1999.]). I don’t know if you’ve accurately quoted Kerry or not, but presumably he was referring to the fact that my own analyses have shown little evidence that the AMO is associated with any detectable oscillatory pattern in the tropical Atlantic SSTs relevant to Atlantic Tropical Cyclone development. –mike]

    Comment by Chip Knappenberger — 2 May 2006 @ 10:55 AM

  89. Gray associate Phil Klotzbach has posted an in-press GRL paper here (thanks to Roger Pielke Jr. for the link). It seems to be a frontal attack on Emanuel and Webster et al. The lack of any co-authors is interesting, especially as I don’t think Klotzbach has a PhD.

    Comment by Steve Bloom — 2 May 2006 @ 11:19 AM

  90. Re: 89. Klotzbach is a Gray PhD student, who apparently has now taken over primary responsibility for the Gray et al. seasonal hurricane forecasts. The paper we linked to is peer-reviewed, and rather than being an “attack” on anyone, in my view it should properly be viewed as an effort to advance the evolving science of tropical cyclones and climate. Klotzbach raises some interesting questions for the scientists to discuss, and from the standpoint of my research, he provides extremely valuable information related to disaggregating the factors underlying the global growth in disaster losses.

    Klotzbach has also posted some “talking points” on the paper here:

    And we’ve opened up a discussion (surprisingly silent so far!) on this paper here:

    We welcome discussion. Thanks.

    Comment by Roger Pielke Jr. — 2 May 2006 @ 11:45 AM

  91. Re: 87

    Grant, you are quite right. The old astronomers didn’t have the tools. But Gray does have: data, model results and theory but refuses to use them or believe in them. Rather, he conjures up new relationships to fit the result he wants. Why? I think he really believes that all climate change is natural and therefore all contrary evidence. It seems to me to be more of a religious belief than a scientific one.

    Comment by pjw — 2 May 2006 @ 12:03 PM

  92. Regarding the various points raised on the mechanism accounting for the Dust Bowl –

    I’m glad this topic came up, since it gives me the chance to emphasize that the criticism of Gray’s claims about the influence of THC fluctuations on climate should not be taken to mean that fluctuations in ocean dynamics have no significant effect on climate. To the contrary, natural fluctuations on decadal and longer time scales can have a big influence, especially on precipitation patterns, and the the way ocean dynamics responds to GHG forcing is almost certainly a big player in determining what regional climate change patterns will look like. For the specific subject of the Dust Bowl, I point people to the excellent summary of research on the influence of SST on N. American precip, by Richard Seager at . This work indicates that the Pacific ocean temperature patterns play the biggest role in the Dust Bowl and similar droughts. It doesn’t take on the question of what kinds of changes in the ocean current patterns might have led to these SST changes, though.

    Comment by raypierre — 2 May 2006 @ 1:13 PM

  93. Chip Knappenberger — As I understand it, RealClimate posts, together with the comments, are ‘archival’ in that the intent is to perserve all the text ‘forever’. So in a wide variety of academic disciplines, citing this material would be perfectly accetable. All that is required is enough linkage information that anyone reading your work could, if they wished, go check the original post or comment themselves.

    There are several minor variations in approved citation style. Looking at almost any entry in the on-line Encyclopeda Britannia will illustrate a few of the acceptable styles.

    [Response: I think citation of material on web sites is a somewhat gray area, at least in academic journals. Digital archives maintained by organizations like AGU or AMS have a clear status, because the digital version of the journal article is now the version "of record," and these hopefully long-lived organizations have committed to maintaining a digital archive in perpetuity. That still makes a lot of people nervous, since if a publisher goes bust, the print versions of journals don't disappear from libraries, which is not the case for digital archives. Sites like RealClimate are more problematic, since we have no way to guarantee how long our material will remain available -- though we do intend to stick around, and have the intention of keeping our articles available in the original form in which they are posted. Still, citing RealClimate will never be the same as citing the New York Times or the AGU journals. What complicates things even more is that many of the links provided on RealClimate and other sites are to material that may itself be transitory. --raypierre]

    Comment by David B. Benson — 2 May 2006 @ 1:46 PM

  94. The “Digital Archive” — — (a.k.a the “Wayback Machine”) can be used to find/cite and retrieve material that’s disappeared from the official resources on the Web.
    An example, last I wanted to reread the famous 1994 paper “Ozone and Global Warming: Are The Problems Real” by Sallie Baliunas, which used to be available online from the George C. Marshall Institute, in which she said among much else,:

    “ozone recovers every year after a month or so. The dramatic Antarctic ozone decline is a temporary annual event…. the “hole” cannot gobble up the rest of the world’s ozone; the hole is confined to the frigid isolation of the Antarctic stratosphere’s polar vortex…. the ozone hole cannot occur in the Arctic.”

    She went on to argue that global warming was as flawed as the “ozone hole” notion:

    “… compare the forecasts to very accurate temperatures measured by satellites …. The Arctic is important because the forecasts say that Arctic temperatures rise fastest of all and thus provide a stringent test of the greenhouse warming theory…. the satellite readings show that the
    temperature has not changed at all in the last 15 years in response to the buildup of greenhouse gases … warming in the next century, at present rates of increase in the greenhouse gases, will be less than 0.5 [degrees] C. Spread over a century, that warming will be insignificant and indistinguishable from the natural fluctuations in the earth’s temperature. … Why are the predictions so far off?”

    Material like this shouldn’t be lost, it’s priceless for perspective on how the science was used to make the public policy decisions in the late 1990s.

    Only the web archive had a copy when I looked for it; found here:*/

    Comment by Hank Roberts — 2 May 2006 @ 4:35 PM

  95. In his paper,

    Gray wrote … 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. …

    Gray concludes with … I anticipate global temperature conditions will change as they have in the past. I expect to live to see the start of a global cooling pattern and the discrediting of most of the anthropogenic warming arguments. The world has more serious problems to worry about.

    Does Phil Klotzbach agree with Gray on that?


    [Response: I think what matters is what Klotzbach wrote in his GRL article. In this matter, the devil is in the details of how the data analysis is done, and I look forward to seeing how the ensuing dialog between Klotzbach, Webster and Emanuel shakes out. --raypierre]

    Comment by pat neuman — 2 May 2006 @ 6:00 PM

  96. From #12: “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–”
    Many comments are being made about Gray and THC, but nobody has replied to the question raised in this post as to why only El Nino may affect global temperatures.

    [Response: Who said only El Nino can affect global temperatures? As I said, in the very statement you quoted, the THC does affect the global mean temperature -- just not in a way that duplicates the anthropogenic global warming signal. For the case of a weakening THC, the sign isn't even right. --raypierre]

    Comment by Gerald Machnee — 2 May 2006 @ 7:01 PM

  97. Re: 95.

    I still would like an answer … Does Phil Klotzbach agree with Gray on that?

    I would also like to know if there is anyone out there who agrees with the last two sentences that William Gray made in his paper (95.).

    Comment by pat neuman — 2 May 2006 @ 8:48 PM

  98. Raypierre, Re your comment to 85
    Therefore there will be a ngative feedback: expanding sea ice will mitigate global warming.
    Why is Antarctic sea ice expanding?

    Comment by Bryn Hughes — 2 May 2006 @ 11:48 PM

  99. Re 88

    Concerning the AMO-like oscillation in unforced climate model runs (Knight et al.):

    I have some concerns about the relation of the simulated patterns with the AMO:

    - the range of periods (40-130 years) in the paleodata is so huge that it is questionnable if this is anything else than a random (possibly forced) signal. It is hard to find any regular signal in the AMO proxy reconstruction by Gray et al. (2004). As also pointed out by Emanuel, the global temperature signal shows periodicities in the 50-70 year band due to the accidental superposition of non-periodic external forcing, at least during the last 150 years. Of course it is possible that there is an additional natural cycle at the same time, but it would have to be more or less exactly in the same phase as the overlaying forcings, which is possible but not very likely. Delworth and Mann (2000) analysed global temperature for their frequency analyses of instrumental data.

    - the oscillation due to THC variations in the models used in Delworth and Mann (2000) and in Knight et al. (2005) are in a different frequency range and thus depend on the model: 50-80 years vs. 70-120 years, respectively. The match until now only concerns the frequency band, nothing is said about matching of the phase. There isn’t any observational evidence that such a THC oscillation as seen in the models exists in the real world.

    Conclusion: given the mentioned frequency ranges the only thing one can say is that both, modeled THC and temperature observations, show multidecadal variation. However, this is a very weak basis for arguing that there is a causal relationship. On the other hand, the oscillating temperature signal can be well explained with external forcings.

    [Response: Urs, thanks for your comments on this. Your points are well taken, but I don't agree with several statements you've made. While I can't speak for Gray et al (note: this is a different Gray!), other analyses of proxy reconstructions have specifically rejected the null hypothesis of red or coloured noise. i.e., there is multidecadal long-term variability that cannot be dismissed as noise--there is indeed evidence that it is bandlimited in the 50-70 year timescale range. Detecting such a signal in the short observational record is very difficult indeed, and is typically attempted through an analysis of the spatiotemporal variance in the record, which can allow the detangling of competing low-frequency signals--be they externally forced or internally generated--by exploiting spatial orthogonality (though not without some strong caveats). Please refer to the detailed literature provided in response to Chip K.'s previous comment above. The reason for believing that there may be a natural multidecadal oscillatory signal in the observations is based on the similarity in both the timescale and the spatial pattern of the signal (see again the model/data comparisons described by Delworth and Mann). All this having been said, where we may concur is that much of the 20th century variability that has been attributed recently to the "AMO" (e.g. tropical Atlantic warming and Tropical Cyclone activity) would more plausibly appear to be a manifestation of the response to competing anthropogenic forcings (i.e. 19th-20th century greenhouse forcing with a substantial offsetting tropospheric aerosol forcing in the Northern Hemisphere which really kicks in during latter half of the 20th century). - mike]

    Comment by Urs Neu — 3 May 2006 @ 7:47 AM

  100. >85, 98
    Bryn, first you “surmise … conjectures” that sea ice will increase.

    Ray replied that “what you are saying … would be correct if THC were the only thing affecting Arctic climate.”

    THC change and climate change from global warming are, this time, both happening together — your surmise conjecture is not correct.

    Then you ask “why is Antarctic sea ice expanding?”

    Question — who says Antarctic sea ice is expanding? Over what period? And what is your source/cite/reference? Where did you read this, who are you relying on for your facts?

    [Response: Your criticisms regarding the Arctic and Bryn's false inferences regarding a purported stabilizing effect of sea ice are on-target. However, with regard to the Antarctic, it is true that sea ice is retreating strongly only in one sector, with increases that more than compensate in other sectors. At least, that's been the pattern over the last decade or so (see, or William's comments at ). Antarctic sea ice has a very strong seasonal variation, and the global warming signal is not yet as dominant in the Southern Hemisphere as in the Northern, because of the thermal inertia of the massive Southern ocean. Hence, oceanic fluctuations have a better chance to dominate the pattern. Right now, I'm looking into what the AR4 models do to 2oth century Antarctic sea ice, to see whether they give a clear indication yet as to what we should be seeing in the Southern Hemisphere. Certainly, all the models predict that ultimately (by 2050) Antarctic sea ice should be dominantly in retreat. --raypierre]

    Comment by Hank Roberts — 3 May 2006 @ 10:52 AM

  101. Re 89,90

    After a look at the Klotzbach paper, I can’t see anything new or anything contradictory to Emanuel (2005) and Webster et al. (2005)

    Just examining the graphs of Emanuel and Webster et al. it is not difficult to estimate the results that Klotzbach got for the decades 1986-1995 and 1996-2005 (see and you see hardly any trend for the PDI and about a 10% increase for category 4/5 hurricanes. Thus there isn’t any apparent contradiction to what Klotzbach found.

    Neither Emanuel nor Webster et al. have claimed a steady increase. A steady increase cannot be expected, given the interannual variability and the different SST variability in the different basins. Thus the presumption of Klotzbach that the trend in the period he examined should be the same as in the periods calculated by Emanuel and Webster is inadequate. His results match more or less the results of the other studies.

    It looks very much like just another attempt to shorten the period until one finds only small or negative trends (like the negative trend in global temperature after 1998).

    Of course it is important to look closely at the correlation between SSTs and hurricane intensity. It is well known that other factors are important for hurricane development, and therefore the correlation to SSTs is not expected to be very high (and also depends on the time scale examined). However, Klotzbach finds, that in both basins with a significant TC trend (North Atlantic and Northeast Pacific) there is a significant correlation (even with trends of the opposite sign), a conclusion not far from what Hoyos et al. have found…

    Comment by Urs Neu — 3 May 2006 @ 1:59 PM

  102. Re comment to 99

    Mike, thanks for your comment.
    I do not at all dispute that there is a 50-70 year cycle in the instrumental data. Your analyses seem convincing, especially the similarity of the patterns.
    However, Knight et al found also a similar pattern in their model, but in the 70-120 year range. Why that?
    And there still remains the problem that external forcing produces a nice oscillation in the 50-70 year range at least from 1860-2000. It would be interesting to look at the patterns of this pseudo-oscillation.

    Comment by Urs Neu — 3 May 2006 @ 2:10 PM

  103. Thanks a lot for your discussion on global warming and its effects. U have removed all the misconceptions on the physics of climate, how its changes and its causes. Its time we should do something about this global warming otherwise it would be too late.

    Comment by william — 4 May 2006 @ 8:51 AM

  104. Post 103. William is that you just getting fed up or what?

    Comment by Eachran — 4 May 2006 @ 9:55 AM

  105. Beg pardon if this has already been called to your attention, but Nature has a news item related to the debate: Tempers Flare at Hurricane Meeting. Unfortunately, I don’t have a subscription. Anyone else read it?

    Comment by da silva — 4 May 2006 @ 2:48 PM

  106. Nature
    Published online: 3 May 2006

    Tempers flare at hurricane meeting
    Researchers debate effects of climate change.
    Alexandra Witze

    Monterey, California –

    Hurricane Wilma helped to make 2005 a record hurricane year, but is global warming to blame?

    Last week, meteorologists gathered in Monterey, California – the meeting was to have been held in New Orleans – to hear new evidence supporting the proposed link between rising sea surface temperatures and more-powerful hurricanes. The fresh crop of research was triggered by two papers arguing for that connection, published by coincidence during the height of the devastating Atlantic hurricane season of 2005 (K. Emanuel Nature 436, 686-688; 2005; P. Webster et al. Science 309, 1844-1846; 2005).

    The effects of global warming, many say, are already in evidence. “It’s not going to happen in the future – it is actually happening now,” says Greg Holland of the National Center for Atmospheric Research in Boulder, Colorado.

    But not all are convinced, and there were raised voices in the hallway discussions at the American Meteorological Society meeting. At a lively panel discussion on 25 April, the moderator accepted audience questions only on written cards, and admonished the speakers not to indulge in personal attacks. This prompted Christopher Landsea, of the National Hurricane Center in Miami, to quip: “I get along personally with everyone in the field, and I want to continue that – even if they’re wrong.”

    At issue is whether the historical record of cyclones is complete enough for accurate conclusions to be drawn about changes from past patterns. Many researchers called for the databases to be brought up to date by including modern assessments of past storms, including their intensities. It is a daunting task that, for now, is being done only for the Atlantic basin by Landsea and his colleagues.

    Even given the gaps in the database, several new studies suggested that rising sea surface temperatures are having a noticeable effect on cyclones. Peter Webster of the Georgia Institute of Technology in Atlanta, co-author of one of last year’s papers, presented data hinting that not only are hurricanes growing more intense over time, but that the length of the storm season has increased as well. Starting from 1950, he told the meeting, the storm season has grown longer in the Atlantic by about five days per decade, in the northeastern Pacific by eight days per decade, and in the northwestern Pacific by ten days per decade.

    In Britain, researchers at the Benfield Hazard Research Centre in Surrey have run climate simulations suggesting that half the recent rise in hurricane activity in the North Atlantic can be explained by the observed increase in sea surface temperature in the region where these hurricanes develop. A warmer ocean would, in theory, provide more fuel for hurricanes to intensify.

    And in Japan, a team has used the Earth Simulator supercomputer to run high-resolution simulations of global climate, both in today’s conditions and in a world warmed by higher levels of atmospheric carbon dioxide. Preliminary results suggest that, in the latter scenario, the number of tropical cyclones would drop by about 30% worldwide. But the number would rise in the Atlantic, and storm intensity would increase worldwide (K. Oouchi et al. J. Meteorol. Soc. Jap. 84, 259â??276; 2006).

    Kerry Emanuel, a hurricane expert at the Massachusetts Institute of Technology, and author of the other paper published last year, says that many of these models need more work before firm conclusions can be drawn. But he spent his time as a panellist demolishing another popular tenet of climate research: that a natural temperature cycle known as the Atlantic Multi-Decadal Oscillation (AMO) controls the formation of Atlantic storms during the peak of the hurricane season. Removing the oscillation would remove one of the last arguments that hurricane patterns are driven by a natural cycle.

    “There may be such a thing as an AMO, but it’s not affecting the sea surface temperature in the North Atlantic in the late summer,” says Emanuel.

    Few of these studies have appeared in peer-reviewed journals yet, and not everyone is persuaded by the conclusions. Johnny Chan, of the City University of Hong Kong, presented data suggesting that in the northwestern Pacific, numbers of typhoons do not track with rising sea surface temperatures.

    One major critic is William Gray, a longtime forecaster at Colorado State University, Fort Collins, whose climate theories have been criticized by many researchers. He continued to insist that hurricanes are driven more by natural patterns of ocean circulation than by human-induced global warming. “I don’t care what anyone says – in the end the data will prove this to be true,” he says. “Why try to read all these demonic influences into the system?”

    Forecasters, including Gray, are predicting that a busier-than-usual Atlantic hurricane season will start on 1 June.

    Comment by Steve Bloom — 4 May 2006 @ 3:09 PM

  107. You might start by getting the name of the organization right. It is American Association of Petroleum Geologists. I am a member. The geology community is far from unanimous in supporting the notion of manmade global warming. The earth has a very long history of warming and cooling, mostly related to the sun. Check out Newsweek’s article (4/28/1975) “The Cooling World”, complete with very dire predictions. Global warming is mostly about politics and left-wing solutions to problems.

    [Response: Before you put your ignorance too much on display, why don't you check out the various RealClimate articles about the supposed global cooling scare. So far you're not impressing me very much. I have met many petroleum geologists whose scientific judgement is quite respectable, and I'm happy to say you are far from typical. --raypierre]

    Comment by Mark — 4 May 2006 @ 8:51 PM

  108. Re: #107

    The geology community is far from unanimous in supporting the notion of manmade global warming.

    But the climatologist community is very near to unanimous.

    Check out Newsweek’s article (4/28/1975)

    Honestly, I don’t mean to be flippant, but around here, “Newsweek 1975″ isn’t exactly an impressive reference.

    Comment by Grant — 4 May 2006 @ 10:08 PM

  109. You live in Minnesota. What have you noticed? Any of this will be familiar if you hunt, camp, canoe, or read any science outside your immediate profession. Does this surprise you?
    Do you find it incredible?

    [Response: Note: I deleted a comment by Mark in which he made some inflammatory accusations, but also mentioned he lived in Minnesota and would like to see some global warming. That's what this refers to. --raypierre]

    Minnesota, 2006

    “…. there may be no greater poster child for what’s happening on the planet than the Minnesota moose.

    “Scientists have known for a very long time, they’re quite sensitive to temperature.

    “Mike Schrage, with the annual moose census in Minnesota says the animal will actually pant when the temperature gets above 67 degrees Fahrenheit. Schrage and his colleagues have spent years counting moose here.

    “… There were four-thousand moose here in the late eighties. Today there are 250. The rate of pregnancy here is low – half of what’s normal. And moose are dying here – faster – than normal.

    “Scientists tell us it’s not that “heat” is the direct cause of these deaths. But increased temperatures do cause a lot of extra stress on the animal.

    “Specifically, these moose are dying from parasites: brain worms and liver flukes. Mark Lenarz with the State Department of Natural Resources says it appeared the parasites “caused those individual moose to starve to death.”

    “Lenarz says that’s “really contrary to what parasites are supposed to do.” Parasites are not supposed to kill the animal.

    “In trying to figure out – why – this is happening, scientists have become focused on ‘temperature’. Lenarz says, “If you’re a moose, and it’s the middle of summer, and you’re panting, you just have a lot less time for eating.” In the end, he says, many of these moose cannot cope with the added stress. Lenarz says the moose are dying in greatest numbers â�� within a year of a very hot summer.

    “…. in Northwest Minnesota, where the moose are dying, the growing season has increased 39 days in the last 41 years. Record dew-points make it feel even hotter than it is.

    “Mark Seeley, a climatologist from the University of Minnesota, told us “in the summer of 2005 we had dew points in the 80′s. This is like Bombay, India. It’s not like Minneapolis/St Paul!” In fact, we’ve seen dew points in the 80′s here seven of the last eight summers.

    “That kind of air can spur greater storms. Precipitation is up here 20 percent in the last century.

    “… Even Minnesota’s great pine forest is at risk. Not just because of the blow-down, but because of the kinds of trees scientists see coming up underneath it. They are the type of trees usually found growing much farther south.

    “Wildlife biologist Bill Berg says, “They’re finding maple basswoods coming up in some of the blow-down area at least 50 years ahead of the predicted timelines.”

    “Berg has been living and working in northern Minnesota for decades. He’s seen the earlier mating season of the grouse, and the expanding range of wild turkeys, raccoons, opossums and skunks. He says they are animals that could not survive so far north before.

    “The realization of climate as a factor in all this, he says, is relatively new. “Before we were kind of like why is this happening,” he said. “And then people, myself included, started putting temperature changes into this. We added it as a variable. And it’s probably the most important variable right now.”

    “Fisheries scientists can see the impact of warming lakes, more toward the central and southern parts of the state. In winter it’s obvious with thinner ice.

    “And in the summer on Lake Pepin they’ve already begun to measure the impact on the walleye population. They believe warmer water is causing larger walleye to grow more slowly. It is also believed to be impacting reproduction.

    “Don Pereira, a scientist with the state Department of Natural Resources says, “What we saw in those Pepin data, in those summers when they (walleye) didn’t grow very well because it was really warm, the following spring there was reduced production of young walleyes on Lake Pepin.”

    “On Lake Mille Lacs, Pereira says the warmer water has resulted in a serious blow to the tullibee population. Tullibee is a feeder fish for walleye and northern pike. It had a strong presence on Mille Lacs for a number of years. But after the scorching heat of 2002 fisheries staff failed to net a single one.

    “There can be a number of factors that have contributed to that, but we know we’ve had very warm summers since the late eighties and we know that this species die when we have really warm summers,” Pereira said.”

    Comment by Hank Roberts — 4 May 2006 @ 10:43 PM

  110. Wow. That’s weird because Maine moose have increased.

    [Response: Forgive me if one-liners like this leave me a little unimpressed. Perhaps you'd like to let us know something about the data on the Maine moose population, how it relates to the regional climate change to date in the area, and what will happen in the out years as climate continues to warm and the areas that escape substantial warming are reduced. The point of the preceding post wasn't that Moose are supposed to be indicators of global warming, but rather that warming has known deleterious effects on natural ecosystems. --raypierrre]

    Comment by Mark A. York — 5 May 2006 @ 12:00 AM

  111. SOHF, ray?

    [Sense Of Humour Failure]

    [Response: Nah, just too much coffee all at one go. Sorry, Mark (York) if I got grumpy. Happy moose watching, or even hunting. --raypierre]

    Comment by Gareth — 5 May 2006 @ 6:19 AM

  112. More, I think, a request for Mark to expand beyond ‘weird’ to ‘science’ — he knows how to dig for details and can backtrack for cites. People in other states may well want to look at what’s happened in Minnesota for cautionary information.

    One could for example compare summertime temperatures in the animals’ ranges — northern and central Minnesota and Maine (is the coastal state’s summer weather cooler than the midwestern state’s, below the temp. at which moose have to spend time panting to reduce body temp?) Is the Maine moose herd known different than the two herds in Minnesota (read the original page I excerpted from; there’s a regional difference between Minnesota herds too); are there different kinds of parasite loads in the two states? Are the parasites moving farther north in the Midwest?

    Short answer is, our petroleum geologist visitor hadn’t noticed any of the many changes documented by biologists in his own home range.

    How scientists observe and inquire is the focus of discussion here (and helping us to think scientifically before making decisions about what to do next).

    Of course one could assume that Minnesota has left-wing moose ecologists and Maine has right-thinking moose ecologists. But that would be wrong.

    Comment by Hank Roberts — 5 May 2006 @ 11:04 AM

  113. Well all it was is an observation not an all-encompassing conclusion. Since I would be considered left-wing of sorts there is no correlation there either. I was just surprised is all. Other than that I don’t know about the implications. Maine has a lottery hunting system now and has for a number of years. I grew up there and moose have always been plentiful in my lifetime. I would wonder if they have declined in Maine as well?

    Comment by Mark A. York — 5 May 2006 @ 2:48 PM

  114. No problem Ray. It says there are around 29,000 animals in the Maine population as of 2001.

    Comment by Mark A. York — 5 May 2006 @ 2:57 PM

  115. Chuckle.
    Maybe what we’re finding out is that global warming has no immediate and observable effect on petroleum geology (I suppose erosion rates and acidification of lakes based on surrounding rock typep ought to come within a geologist’s ambit, more generally, and be noticeable).

    Comment by Hank Roberts — 5 May 2006 @ 3:05 PM

  116. A quote from AAPG, “Our concern is that the geologic perspective generally has been missing from the debate on global warming. Geoscientists have a perspective that is important to this issue, especially the understanding of ancient climates and climate changes in relation to geologic time. AAPG recognizes that that we have members on both sides of this debate and we respect their opinions and encourage them to be part of the scientific process and discussion.” I think this is a very reaasonable statement.

    Newsweek (4-28-1975) was reporting the prevailing notion in the “scientific community” at that time. I remember the talk in the late 70′s that the ices ages were returning. Many of us are old enough to remember that.

    What about talk of global warming on Mars? How do you explain that one? There is one common denominator–the sun.

    The fact is that the climate scientists are far from unanimous on global warming. Perhaps the believers just get a lot more favorable press form “mainstream” outlets.

    Please don’t make this site a subsidiary of the dailykos.

    Comment by Mark — 6 May 2006 @ 11:46 AM

  117. Why is it these people just keep recycling debunked myths?

    “There are lots and lots of climitologists [sic]that subscribe to the Global Warming meme. There are also lots and lots of skeptics over this issue. One thing that is absolutely true is that according to many, only 0.278 % of the green house gases are man made. These gases include C02 (less than 3%) and water vapor which alone accounts for 95+% of the total green house gas. In fact, the two combined account for 99.44% of the total. Interestingly enough, the Department of Energy does not list water vapor as a green house gas even though it is the largest single green house gas. Of course, I will present both sides, there is argument to Hieb here Who is right? Probably a little of both, it is warming a bit, tales of catastrophe belong in the round file cabinet. Skeptics are absolutely correct to be skeptical, it is the scientific principle in research. True believers are people that demand that you see things their way…kind of like lefties huh?”
    They use this same site and counter with this one:

    False dilemma fallacy in full play. Unfortunately newspapers do the same thing. One commenter said this about being referred to RC: “why do people from the left always refer us to RealClimate, as if the people there were credible?”

    Because they are.

    Comment by Mark A. York — 6 May 2006 @ 12:00 PM

  118. A quote from AAPG, “Our concern is that the geologic perspective generally has been missing from the debate on global warming. Geoscientists have a perspective that is important to this issue, especially the understanding of ancient climates and climate changes in relation to geologic time. AAPG recognizes that that we have members on both sides of this debate and we respect their opinions and encourage them to be part of the scientific process and discussion.” I think this is a very reaasonable statement.

    I agree, it’s a very reasonable statement. I disagree that the geologic perspective is “missing,” rather that climate scientists have a very good perspective on paleoclimate.

    Newsweek (4-28-1975) was reporting the prevailing notion in the “scientific community” at that time. I remember the talk in the late 70′s that the ices ages were returning. Many of us are old enough to remember that.

    Definitely check out posts on this site about the “ice age” scare.

    What about talk of global warming on Mars? How do you explain that one? There is one common denominator–the sun.

    There’s another common denominator: carbon dioxide. And, what about global super-warming on Venus?

    The fact is that the climate scientists are far from unanimous on global warming. Perhaps the believers just get a lot more favorable press form “mainstream” outlets.

    I believe you’re mistaken. In fact it’s the deniers who get vastly disproportionate press coverage. Bear in mind that the IPCC reports represent the combined effort of about 2000 climate researchers. Most of them never get any press. But a small number of denialists get regular op-eds in the Wall Street Journal.

    Comment by Grant — 6 May 2006 @ 12:06 PM

  119. Mark, at least read the threads here discussing the frequent skeptic claims, before you restate them. (Preferably, tell us where you read them, and why you trust the source where you found them, and whether they were provided to you with any cites/footnotes/references that you could check for yourself.)

    Many of the skeptic claims are PR from industry sites and have no basis in the scientific literature.

    Trolls and PR people don’t footnote (because they’re making this stuff up, or repeating baseless claims).

    You can check many of the skeptic claims easily. For your latest:


    Was an imminent Ice Age predicted in the ’70′s?
    Google Results: about 1,270,000 for 1970s claim ice age.

    Skeptic Claims Generally, with science cites:

    Libertarian perspective:

    Look for the footnotes when you see claims made, and read the science. Tell us what the basis is for what you assert. The above links are examples of claims with sources cited so you can check what’s said yourself. As you would do in any scientific study, do here.

    Comment by Hank Roberts — 6 May 2006 @ 1:57 PM

  120. #116, “Perhaps the believers just get a lot more favorable press form “mainstream” outlets.”
    Nonsense. I took a look at my Countries weather today, almost all major cities are having above normal temperatures, that is what is driving some journalists. They are seeking answers about this warming which is occurring now, they are doing their jobs.

    [Response: If journalists are stimulated by above normal temperatures to look into the broader climate change issues that's a good thing. Of course, no short term period of above (or below) average temperature tells you much one way or another about climate change. A string of several years of new records does begin to hint at something, and an increase in the occurence of extreme events tells you something, but it takes a good many years of statistics before the picture becomes clear. I like the way the studies of the last European heat wave put it -- this kind of event is expected to become more probable in a doubled CO2 world, but there is no attribute any one particular event to global warming. Same situation for, say, Katrina. --raypierrre]

    Comment by wayne davidson — 6 May 2006 @ 2:00 PM

  121. #120, Raypierre, I believe that Chaos with respect to temperature variations is not so prominent anymore, that is catching the attention of many. When nearly every big city
    is above normal almost simultaneously, questions arise, immediate answers are sought. May be GW GCM’s have projected this for sometime in the future, it is nevertheless a great phenomenon.

    Comment by wayne davidson — 6 May 2006 @ 2:16 PM

  122. To amplify on the response to Mark in Comment #118, it is utterly unjustified to say that a geological perspective is missing from climate change studies. Usually this is taken by some of the less thoughtful petroleum geologists to mean that “global warming believers” don’t realize that “climate changes all the time” (whatever that latter is supposed to mean). In fact, the study of past climate changes is at the very heart of the way climate research operates. There is a whole journal devoted to it (Paleoceanography),and almost any issue of JGR-Atmospheres has something about paleoclimate in it. The best of this work combines modeling with geological studies of the proxy record. A lot of my own recent work is on Neoproterozoic climate, and without careful geological studies by Paul Hoffman and others (ironically, the same kind of field studies that petroleum geologists use to spot promising formations) my whole subject would be toast, for lack of data to help constrain the models. Going more recent, the record of the Pleistocene (relying on both ice core and marine sediments) is a big part of our understanding about how the climate system responds to CO2 and other forcings. The LGM is in fact a major test of the model sensitivity to CO2, as has been discussed in a number of places on RealClimate. In between you have hothouse climates like the Cretaceous, which cannot be explained without the greenhouse effect of elevated CO2 (and so far have not even been completely explained with it, though the gap may be more due to data than the theory). Let’s not get into the claim that Veizer showed it’s all cosmic rays and not CO2, since that’s been thoroughly debunked.

    I won’t tar the whole petroleum industry with the same brush handed to us by the spokesman for the S.A.P.G. who lauded Crichton’s book. As an indication of the extent to which the petroleum industry accepts the very same climate physics used in understanding global warming, at least one major oil company is using climate simulations of the Cretaceous (based on CO2 induced warming on top of geography changes) to spot promising oil formations. In fact, one of Paul Valdes’ industry-funded Cretaceous simulations was more or less embargoed from publication for five years because of its potential value to exploration. I hasten to add that Paul is one of the most respected climate modellers in the business, and his case shows that it is entirely possible to get some funding from the fossil fuel industry without compromising one’s research. The paleogeographic atlas project at U. of Chicago has also gotten funding from the oil industry from time to time.

    That’s not to deny that some industry groups do indeed fund work for hire whose intent is to spread confusion about the state of climate science.

    Comment by raypierre — 6 May 2006 @ 2:27 PM

  123. Hi, raypierre. My impression is that models of the Cretaceous climate have a hard time reproducing the amount of warmth in the polar regions and continental interiors. In particular, there are very large (more than 10 watts per square meter) uncertainties about forcings from cloud cover. I am surprised that a general circulation model (if that is what they used) could achieve regional accuracy sufficient to predict the formation of oil. I wonder if you can point me to some references to help me understand this better?

    [Response: You are right about the nature of the problems with Cretaceous simulations. They are too cold in the winter in continental interiors, and when CO2 is turned up enough to make the poles warm enough to melt ice, the tropics tend to be too warm (though that latter may be a data problem, not a model problem). I don't know much about petroleum geology, but my recollection is that the organic precursors to oil are in high-productivity marine environments, and those are less affected by the continental interior problem. For the gradient problem, I believe the idea was to set the CO2 level at something that achieved a reasonable match to the available Cretaceous data, even if it somewhat overestimated the gradient, in the hopes that the oceans would still be close enough to the real thing to provide some guidance as to high productivity regions. I have sent Paul some email to see if there is any work in the petroleum exploration literature which explains how this is done -- for all I know, the details may be proprietary. I am also checking up on the publication status of the specific Cretaceous simulations I referred to, and will post the references once I hear from Paul. --raypierrre]

    Comment by Blair Dowden — 6 May 2006 @ 5:54 PM

  124. Apropos of Blair’s query:

    I’m still waiting to hear from Paul Valdes, but a quick check of Science Citation index tells me that his “best” Cretaceous simulation (which I have seen!) has not appeared in print yet. To get an example of the state of the art in Cretaceous model-data comparison, insofar as it’s reached publication, you can take a look at the following from the NCAR group:

    Title: Late cretaceous ocean: coupled simulations with the national center for atmospheric research climate system model
    Author(s): Otto-Bliesner BL, Brady EC, Shields C
    Document Type: Article
    Language: English
    Cited References: 52 Times Cited: 12
    Abstract: [1] Deep-ocean circulation may be a significant factor in determining climate. Here, we describe two long, fully coupled atmosphere-ocean simulations with the National Center for Atmospheric Research Climate System Model for the Late Cretaceous (80 Ma). Our results suggest that higher levels of atmospheric CO2 and the altered paleogeography of the Late Cretaceous resulted in a surface ocean state, temperature, salinity, and circulation, significantly different than at present. This, in turn, resulted in deepwater features that, although formed by mechanisms similar to the present, were quite different from the present. The simulations exhibit large overturning cells in both hemispheres extending from the surface to the ocean bottom and with intensity comparable to the present-day North Atlantic simulated overturning. In the Northern Hemisphere the sinking takes place in the Pacific due to cooling of the much warmer and saltier waters compared to the present day. In the Southern Hemisphere the sinking occurs primarily in the southern Atlantic and Indian Oceans. For a simulation with atmospheric CO2 reduced from 6 times to 4 times preindustrial concentrations, the southern branch is reduced by 35% due to less poleward transport of salty waters in the South Atlantic Ocean. Warm waters inferred from proxy data in deep-sea cores can be explained by the high-latitude sites of overturning. These results contradict the traditional hypothesis that warm Cretaceous ocean bottom waters must have formed by sinking in shallow low-latitude seas.

    Comment by raypierre — 8 May 2006 @ 1:08 PM

  125. Gack!

    So — is it the same oil companies that are in public dismissing modeling and climate change as wacky science, while at the same time, without publishing the work, using climate modeling to locate oil?

    Or are these different companies, the Exxon-Mobil group that funds Tech Central Station and so many of the other denial industry outlets opposing modeling, and — who, favoring it?

    I imagine the oil industry can afford to hire very good people, taking them and their work out of the public discourse entirely.

    If I’m deciding on my retirement funds, I’d sure like to know which company, if there is one, both believes in modeling and publicly supports scientists who are doing modeling — and lets them publish, eventually, for the public good.

    This is eerily reminiscent of the history of tobacco science, isn’t it?

    [Response: I wouldn't say it's necessarily the SAME oil companies; that wasn't relevant to my point, which was only that the petroleum industry is not uniformly skeptical about the strong link between CO2 and climate, or about the value of climate models. Also, it wouldn't be fair at all to characterize Paul Valdes as having been "taken out of circulation," if that's what you had in mind. He's continued to be very active in publishing climate simulations, both on things relevant to the LGM and to anthropogenic climate change. It's just this one Cretaceous paper that seems to have been delayed, and Paul no doubt has as big or bigger a backlog of papers to write up as I have, so I wouldn't jump to conclusions about the reasons for the delay. --raypierre]

    Comment by Hank Roberts — 8 May 2006 @ 3:18 PM

  126. Thanks, Ray. I’ll hope the stockholders’ groups clarify which oil companies are completely in denial, which are hypocritical (if any are publicly denying while internally using models) and which — if any –have models or understand yours and are thinking about the future as well as the past.

    Time will tell, if there’s time, and if climate isn’t a ‘tragedy of the commons’ in the short run.

    It worries me to imagine how many not-yet-written papers are no doubt awaiting drafting.

    Comment by Hank Roberts — 8 May 2006 @ 6:01 PM

  127. News article about the latest from Pat Michaels on global warming and hurricane intensity:

    Comment by Dan — 10 May 2006 @ 11:57 AM

  128. Re: #127,

    That makes little sense to me, especially with studies by Emanuel, Curry, et al. which say the opposite. Again, the contrarian crowd is throwing out obfuscations and misinformation to confuse the general public.

    Comment by Stephen Berg — 10 May 2006 @ 1:12 PM

  129. Re #125 and 126: I’ll start the list for you:

    Oil companies in denial: Exxon/Mobil

    Oil companies accepting the science: BP, Shell

    I’m not sure about the rest. [And, I think coal companies, like Western Fuels Association, tend to be heavily denialist since coal is even more carbon-intensive than oil.]

    BP has been particularly good on the issue as they made Kyoto-size cuts in their own greenhouse gas emissions, completing them like 8 years ahead of schedule and noting that they are actually saving hundreds of millions of dollars (i.e., the net cost of these emissions reductions was negative). I think they are now starting to consider the issue of end-use emissions from the products they sell (i.e., the greenhouse gases emitted when you buy your gasoline at BP and run your car on it), which is, of course, dicier for them.

    Comment by Joel Shore — 10 May 2006 @ 1:54 PM

  130. Just to follow-up on what I wrote, here is a link to BP’s web pages on climate change:

    Comment by Joel Shore — 10 May 2006 @ 2:01 PM

  131. The paper mentioned here
    is now available to AGU subscribers. The AGU abstract is here

    From the abstract they agree with Dr. Cheliah and Dr. Webster (if I read them right in the earlier thread) that there’s more than one thing going on. Anyone read the full text? I’m still hoping we hear more from Drs. C. and W. and the others about the earlier papers — that discussion was going to happen elsewhere and appear eventually, presumably in a journal article. Patience ….

    Comment by Hank Roberts — 13 May 2006 @ 2:48 PM

  132. Re Raypierre’s response to post 100
    Antarctic Cooling “because of the thermal inertia of the massive Southern ocean.”
    Gavin wrote a paper attributing Antarctic Cooling to the effects of decreasing ozone in the upper atmosphere.
    Which of these reasons is Scientifically most probable ?

    [Response: There's more than one thing going on in the Southern Hemisphere. My point about thermal inertia is just to explain why the global warming signal is less pronounced so far in the Southern Hemisphere. That does work together with the subtle ozone effects on Antarctic interior climate, though, since subtle cooling forcings have less general Southern Hemisphere warming to fight against. --raypierre]

    [Response: I'll try and clarify. Overall the southern hemisphere will not warm as quickly as the north because of the larger thermal capacity of the oceans. This of course does not predict any actual cooling! However, in the presence of a very mild expected GW signal, local dyanamics can make an important difference. Mainly because of the ozone hole, winds around Antarctica have sped up and this pattern is associated with cooling in the Antarctic interior - consistent with the observations. - gavin]

    Comment by Bryn Hughes — 14 May 2006 @ 11:45 AM

  133. For Mark the petroleum geologist from Minnesota — still with us? — your state senate held hearings on state climate change in 2005. Here’s a link to one presenter’s video:

    Comment by Hank Roberts — 14 May 2006 @ 6:29 PM

  134. Re 132
    So there are two processes causing this Antartic cooling.
    I find it interesting that the only places on earth that are cooling are probably the only one’s to have no air routes across them.

    Comment by Bryn Hughes — 15 May 2006 @ 5:00 AM

  135. [...] In fact in my search to find out just what was behind William Gray’s thinking what I did find was a critical article on the web site entitled Gray and Muddy Thinking about Global Warming. [...]

    Pingback by Just who is William M. Gray? « Rationally Thinking Out Loud — 20 Jul 2007 @ 8:10 PM

  136. [...] quoted as a tropical expert, Gray’s actual prediction record is unimpressive. Read more at RealClimate. This entry was posted on October 14, 2007 at 6:56 pm. You can bookmark the permalink. Comments [...]

    Pingback by ecoTumble » Hurricane Forecaster Stages Category 5 Rant — 14 Oct 2007 @ 1:57 PM

  137. [...] was presented with glee in a right-wing denier paper is just the ice on the cake, as it were…. RealClimate Gray and Muddy Thinking about Global Warming William M. Gray – Wikipedia, the free encyclopedia The Sydney Morning Herald – Wikipedia, the [...]

    Pingback by Global Warming - Page 40 - Speedzilla Motorcycle Message Forums — 15 Oct 2007 @ 12:17 PM

  138. Re: Gore Wins Nobel Peace Prize…

    Although Gray arguments seem complex, his theories are full of holes..


    Trackback by — 15 Oct 2007 @ 2:20 PM

  139. [...] ad hominem attacks. But Dr. Gray also makes scientific arguments, flawed though they are. Read a rebuttal of his recent efforts. It begins: Anybody who has followed press reporting on global warming, and particularly on its [...]

    Pingback by Muddy thinking by a climate skeptic « Later On — 15 Oct 2007 @ 4:00 PM

  140. [...] Fox News Uses Not-So-Expert-on Global-Warming Expert to Try to Discredit Al Gore – Dr. William Gray, who argues that humans are not responsible for the warming of the earth, and says that salinity determines the temperature of the oceans’ waters, was cited on the Fox and Friends show as proof that Al Gore is all wrong. However, The Washington Post reports: Gray’s crusade against global warming “hysteria” began in the early 1990s, when he saw enormous sums of federal research money going toward computer modeling rather than his kind of science, the old-fashioned stuff based on direct observation. Gray often cites the ascendancy of Gore to the vice presidency as the start of his own problems with federal funding. The National Oceanic and Atmospheric Administration (NOAA) stopped giving him research grants. So did NASA. All the money was going to computer models. The field was going off on this wild tangent. [...]

    Pingback by The WAWG Blog » Blog Archive » Bad Deeds for 10-17-2007 — 21 Oct 2007 @ 6:05 PM

  141. [...] Gray and Muddy Thinking about Global Warming A look at William Gray’s contrarian arguments [...]

    Pingback by Understanding Global Warming — 6 Jan 2008 @ 9:23 PM

  142. [...] much all quarters of the atmospheric science community the last few years. Here’s a good summary: RealClimate Since all those debunkings a couple of years ago, Gray has largely stopped trying to argue and has [...]

    Pingback by Sen. Jim Inhofe embarrassing us again... - Page 3 - OKCTalk — 26 Jul 2008 @ 9:51 AM

  143. [...] Gray and Muddy Thinking about Global Warming A look at William Gray’s contrarian arguments [...]

    Pingback by Understanding the Basics of Global Holocene Climate Change « Understanding Global Warming — 16 Mar 2009 @ 8:57 PM

  144. [...] Gray and Muddy Thinking about Global Warming A look at William Gray’s contrarian arguments [...]

    Pingback by main « Understanding Global Warming — 17 Mar 2009 @ 2:43 PM

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