Wednesday, December 16, 2009

Open science & Climategate

Gary Richmond wrote a very nice essay about the Climategate and the poor standards in climate science:
Open Science and Climategate: The IPCC/CRU needs to take a leaf out of CERN's Book (click)
He argues that the IPCC and friends should imitate CERN - which Richmond has enthusiastically written about previously - and adopt the philosophy of open source software etc.

There's a lot of wisdom about the essence of science (and the importance of skepticism and verification), peer review (and how it was devastated), the Harry file in the hacked/leaked CRU documents (and what software standards have been violated according to this file), comparisons with sub prime coding and other things in the software industry (and some promotion of the free software framework - well, I would stay skeptical), questions why professional IT guys were not hired in the climate science (who would also choose different programming languages to deal with the formatting issues), interactions with politics (which partly provide the answer to the previous point), and other things. Recommended.

Gore and ice-free Arctic

Al Gore is suddenly under fire for having said that chances were 75% that the Arctic will be completely ice-free in the summer by 2014. He attributed the statement to Dr Wieslaw Maslowski who denies he has said it.

But as Marc Morano has found out, Maslowski has published a formal paper arguing that the chances are 75% that the Arctic will be nearly ice-free in 5 years. And Maslowski doesn't seem to remember anything similar he has ever said! The reason of his turned coat is apparently that crazily shrill predictions got somewhat less popular recently.

As you can see, the only difference is the word "nearly". Maslowski explains that the word "nearly" meant a 80% reduction of the ice sheet. If the word "nearly" is removed, the Arctic won't become ice-free anytime before 2030, he says.

Well, I think that Maslowski is emitting a lot of fog in this case.

If only 20% of the usual minimum sea ice area (in September) remains, there is nothing that would preserve these last 20%. In fact, I think that the melting gets faster, not slower, as the volume is dropping because smaller bodies of ice have a larger surface/volume ratio, making them more vulnerable to heat exchange. Well, there's also an issue on the opposite side - there can exist statistical islands where the temperature stays significantly below the freezing point for a whole month.

If the first observation is more important than the other, and I think it is (because the boundaries of the ice are always close to the melting point, anyway) - but some simulation would be needed for me to give you a semifinal opinion - then we could say that if it is "more likely than not" for the sea ice minimum to drop to 20% of its normal value in five years, such an evolution has to be due to a fast "trend" that will almost certainly continue and it is therefore also "more likely than not" for it to disappear completely in 6 years.

Whether the implication above is correct or wrong, I think that both probability estimates - by Gore as well as Maslowski - are incorrect. Even if you attribute the whole asymmetry of the Arctic sea ice chart to a trend, the trend has been at most by 1.5 million (disappearing) squared kilometers in 30 years which leads to the estimate of 90 more years to get to zero in the summer.

Not only because the Antarctic has actually seen an increasing trend, I think that the whole 30-year change in the Arctic sea ice area cannot be attributed to a trend i.e. it cannot be blindly extrapolated so my estimate for an ice-free summer is actually much longer than 90 years even if there is an underlying trend.

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