Tuesday, December 11, 2007 ... Deutsch/Español/Related posts from blogosphere

Douglass, Christy, Pearson, Singer

Book alert: Václav Klaus's book is now sold in Germany
This weekly dose of peer-reviewed skeptical literature about the climate will be rather short because we have talked about similar issues many times. In the International Journal of Climatology,
David Douglass, John Christy, Benjamin Pearson, Fred Singer (full-text paper in PDF, backup)
show, in their article "A comparison of tropical temperature trends with model predictions", that the previously discussed "fingerprint" predicted by 22 greenhouse-dominated models disagrees with the observed data summarized in 10 datasets.

Figure 1: Models said "Good bye" to reality. At the key altitudes, reality is about 6 uncertainties of the mean (measured as the standard deviation of the model ensemble divided by the square root of 22-1) away from the models. If you include "submodels" or "realizations", there are 67 of them and the discrepancy jumps to 10 sigma (this is why copying a model many times, as in the "consensus science", will be used against you by the rules of science). If you count the discrepancy in the experimental standard deviations, they will exceed 5 sigma, too. Regardless of these numbers, the picture above says a lot by itself.

The models and observations are compatible near the surface. However, about 5 kilometers above the surface (where the greenhouse effects starts to become relevant) in the tropical zones, models predict between 2 times and 4 times higher warming trend than what is observed. Above the altitude of 8 kilometers, the theoretical and empirical trends have opposite signs.

See also a press release (XML)
The insights strongly indicate that the true mechanisms driving the changes of temperature are not understood and the overall effect of greenhouses gases is being overestimated - between 2 times and 4 times - by all existing models. Note that with this reduction, IPCC's sensitivity between 2 and 4.5 °C gets reduced to the standard 1 °C climate sensitivity which means that the additional greenhouse-induced warming by 2090 will be less than 0.5 °C.

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reader Mike Davis said...

Thanks for the article. The original study can be downloaded in .pdf form at http://www.uah.edu/News/pdf/climatemodel.pdf

I'd like to point out that the sober, objective scientists at RealClimate.org have chosen to "debunk" the Douglass et al study.

There are a couple notable problems with the methodology of the group at RealClimate.org, which should be readily obvious. It would seem that in their haste to discredit the Douglass study, they purposefully misinterpret the paper and willfully manipulate the data.

John Christy responds to their criticism, pointing out that whoever wrote the anonymous article must have been written by "someone of significant inexperience."

Franklym I find it odd that Schmidt and Mann have chosen to take their criticisms directly to the public, where there is little chance for scrutiny except perhaps on Internet forums. Wouldn't the correct way be to publish their challenge to the Journal of Climatology?

reader William Newman said...

"Wouldn't the correct way be to publish their challenge to the Journal of Climatology?"

I certainly wouldn't defend all the webbing practices at RealClimate; e.g., the moderation on the comments might well be completely misleadingly dysfunctional. However, I don't think there's anything wrong with RealClimate or anyone else making a webbed criticism. I would say that your traditional formal way is only *a* correct way to criticize, not *the* correct way.

I would also say, though, that if the thing being criticized is published in an officially edited and archived journal, and months and years pass, and nobody ever gets around to making their criticism in a comparably formal way, that'd be noteworthy enough to call for an explanation if people continue to repeat the informal webbed version as received academic truth.

E.g., last I heard (long ago, and I don't know a convenient webbed way to check, so take this as almost-hypothetical, not necessarily true) that was the situation with an economics journal article called "The Fable of the Keys." It is in an official journal, is a very strong criticism on a high-profile publication. If the author of the paper never got around to addressing the criticism in print, that's noteworthy. As far as I know, he never did, yet the original point of view still seems to get a lot of respect.

(I don't know a convenient way to check that situation online, but I do have a copy of a successful recent book by David Warsh called _Knowledge and the Wealth of Nations_, and that's enough to suggest that a weird situation remains. _KatWoN_ uses the original criticized work as one of its themes (see QWERTY in its index) but weirdly never mentions "Fable of the Keys," only the reports the original criticized paper as fact, as though no criticism ever existed. Odd stuff, I thought, especially considering the approving blurbs from knowledgeable economists on the cover of the book. Someday it'd be interesting to know how "Fable of the Keys" disappeared an official memory hole. Maybe someday Warsh will tell us on his website, but Google "fable keys economic principals" suggests it hasn't happened yet.)

On the other hand, responding through the traditional formal journal system usually takes at least months, and with our handy new technology we can work much faster than that. As an apolitical (I think...) example, see the way that the recent supposed Graph Isomorphism algorithm was criticized: http://scottaaronson.com/blog/?p=304 . The criticism seems to have been clearly correct, and the paper was withdrawn in a few days.

Of course, apolitical can be relative. I think I might lose credibility if I tried to claim apoliticality for anything written by someone who recently remarked he is "bent on destroying" the Democratic "Party's power base." But what Scott said in http://scottaaronson.com/blog/?p=306#comment-17025 differs from that in a vital way, so it should be OK, right? And he's a very sharp guy.

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