Physics be damned
May 29, 2008
Bishop Hill in Climate: Surface

This is really getting quite amusing.

A new paper published in Nature claims to have uncovered an almighty cock-up in the sea surface temperature record just after the Second World War. Previously the temperature records showed a sharp fall, but it turns out that this was wrong. According to the authors:

It turns out that the mysterious drop is due to differences in the way that British and US ships’ crews measured the sea surface temperature (SST) in the 1940s.

Only a few SST measurements were made during wartime, and almost exclusively by US ships. Then, in the summer of 1945, British ships resumed measurements. But whereas US crews had measured the temperature of the intake water used for cooling the ships’ engines, British crews collected water in buckets from the sea for their measurements. When these uninsulated buckets were hauled from the ocean, the temperature probe would get a little colder as a result of the cooling effect of evaporation. US measurements, on the other hand, yielded slightly higher temperatures due to the warm engine-room environment.

The standard logbook entries made at the time contain no information about how the measurements were taken, so the cause was overlooked, says David Thompson, first author on the paper and an atmospheric scientist at the State University of Colorado in Boulder. As a result, the bias — which, although small, was large enough to produce the sharp drop in global mean temperature — was never adjusted for.

Bravo. And the paper gets the full headline treatment in Nature, with editorials on two of the Nature Group's websites.

The only thing is that this cock-up was pointed out nearly two years ago at Climate Audit. As expected, neither the authors or Nature's leader writers acknowledge their debt to Steve McIntyre, a fact which rather gives the lie to their executive editor's claims that Nature is "of the highest quality and independent". I've noted before that they refuse to link to Climate Audit, while being happy to point their readers to environmentalist writers, so this kind of claim is becoming increasingly ridiculous.

Meanwhile, the implications of these findings are starting to sink in. We should remember in passing that the sea surface record is much more important than the land records, because the sea is such a large proportion of the world's surface. Now, all those climate models, which we are told are based on fundamental physics, have included calculations based on the effects of aerosols - pollution in layman's terms - which allow the models to reproduce the post-war temperature drop. The argument goes that all there was a lot of pollution around in the post-war period which depressed temperatures. Now, of course, the temperature drop turns out to be a mistake, the modellers are going to have to start to explain away why their post-war reconstructions are so much lower than the recorded temperatures. Their alternative is to suddenly discover that the effect of aerosols is not as great as previously thought or that aerosol concentrations were lower, but this will just make it look as if they just throw anything into the models which seems to give the "right" answer, and physics be damned.

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