Arnold Kling  

Global Warming Scorecard

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According to an unflattering analysis by Douglas Hoyt, climate models have made 1 correct prediction ("win"), 27 incorrect predictions ("losses"), and 4 predictions that cannot be judged either correct or incorrect ("ties").

Of the models' "losses," the one I consider most damning is the prediction that mid-tropospheric warming should be 50-100% larger than surface warming. The data show the reverse.

Another interesting "loss" is "ocean warming," where Hoyt says,


Simply put, where clouds decrease in amount, the water warms. It has nothing to do with carbon dioxide.

I would do the scoring differently, with a lot more "ties," and some items not counting as predictions. For example, my view is that the global warming models make no predictions about hurricanes, so I would not count those.

Other examples, such as the fact that glaciers started receding 250 years ago, are not so much contradictions of the models as they are neutral to the models, at least in my view. I would count these as "ties."

The scorecard also does not include either of the predictions that I mentioned in this post, both of which appear to be "wins."

I read about Hoyt's scorecard in a paper by Hans Labohm, who also writes,


Some time ago the astronomer Khabibullo Abdusamatov of the Pulkovo Astronomical Observatory in St. Petersburg declared that the Earth will experience a ‘mini Ice Age’ in the middle of this century, caused by low solar activity. Temperatures will begin falling five or six years from now, when global warming caused by increased solar activity in the 20th century reaches its peak. The coldest period will occur 15 to 20 years after a major solar output decline, between 2035 and 2045, Abdusamatov said. This view is shared by the Belgian astronomer, Dirk Callebaut, who expects a ‘grand minimum’ in the middle of this century,

Of course, I would like to know what the "scorecard" would look like for these guys who are forecasting global cooling.


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COMMENTS (10 to date)
James A. Donald writes:

It is a noisy system. So one can always generate any number of correct predictions or any number of contradictions by choosing the right climate proxy and the right begin and end dates.

Notoriously, the infamous hockey stick graph fails to show a hockey stick if you throw out the tree ring data, or if you throw out one particular tree from the tree ring data, or if you *include* more recent tree rings.

dearieme writes:

My forecast is global tepiding.

Jim writes:

"Of the models' "losses," the one I consider most damning is the prediction that mid-tropospheric warming should be 50-100% larger than surface warming. The data show the reverse"

At the risk of being bitterly denounced as a bitter denouncer, I suggest you read something like http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/ before drawing such an unequivocal conclusion. You may also have noted that the 'score' for mid-tropospheric warming is mostly based on old data which has since been corrected, not that you would know that based on what Douglass et al (authors of the one fairly recent cited source) tell you, but since they are notorious cherrypickers of the data (see http://timlambert.org/2004/08/gwarming2/) they're not exactly credible authorities.

It took me about 5 minutes to find all that out. Again I have to wonder why you can't do some proper fact-checking before sallying forth on this issue.

shayne writes:

Concurrence with dearieme on "tepiding".

(Thanks for the chuckle and the only accurate forecast, by the way.)

aaron writes:

I don't know about the pacific circulation paper, but the Pinatoba water vaper paper is a tie at best and probably a loss. It's more proof by assumption.

aaron writes:

I also predict global tepiding.

aaron writes:

Ouch. The pacific circulation letter is far weaker than the Pinatubo paper.

Tom writes:

"my view is that the global warming models make no predictions about hurricanes"

Not what the IPCC report asserts. They expect an increase in the number and intensity of hurricanes.

frankcross writes:

Do you really think that is a reliable, evenhanded assessment of the evidence? Did you look behind the claims to the underlying research?

James A. Donald writes:
"I suggest you read something like http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/ before drawing such an unequivocal conclusion. You may also have noted that the 'score' for mid-tropospheric warming is mostly based on old data which has since been corrected, not that you would know that based on what Douglass et al (authors of the one fairly recent cited source) tell you, but since they are notorious cherrypickers of the data (see http://timlambert.org/2004/08/gwarming2/) they're not exactly credible authorities."

Tim Lambert regurgitates what Real Climate tells us: That tropospheric warming of one tenth of a degree per decade is "exactly what is predicted by the latest models"

As usual, Real Climate lies in its teeth. If you stretch the satellite data as far as it will go, (one tenth of a degree) you still cannot stretch the IPCC models far enough to meet the satellite data. You cannot stretch anything from the IPCC down to tropospheric warming of a tenth of a degree per decade

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