Thursday, September 17, 2009

Sea Ice

Sea ice grow.

Grow, ice, grow.

David Friedman looks at figures for the extent of arctic sea ice, and how they compare with claims made about them.

Regular readers of this blog will remember a series of posts (the three links are to three different posts) a few months back dealing with the question of whether NASA/JPL was lying when they claimed on a JPL web page that:

"The latest Arctic sea ice data from NASA and the National Snow and Ice Data Center show that the decade-long trend of shrinking sea ice cover is continuing."

I argued at the time that the latest data actually showed the shrinking to have reversed, although there was no way of knowing if that was more than a temporary deviation. The discussion got me into a correspondence first with someone at NASA who turned to be a publicity person not a scientist, than with a scientist at NSDIC. It also resulted in a lot of comments on this blog.

Out of curiousity, I checked back today on the NSDIC web page, and found:

"The 2009 minimum is the third-lowest recorded since 1979, 580,000 square kilometers (220,000 square miles) above 2008 and 970,000 square kilometers (370,000 square miles) above the record low in 2007."

Or in other words, the extent of arctic sea ice has been increasing for the last two years, contrary to the claim I quoted above.

To avoid irrelevant comments, I am not arguing for or against claims that the greater extent doesn't really count because it is thinner ice or that all the evidence taken together still supports long term shrinking of arctic sea ice. My claim is simply that the quote above, which is still up on the JPL web page, is false. When people lie to me about the evidence for their conclusions, offering other evidence that their conclusions are still true is not an adequate defense.

 Rather than making the claim, they should present the evidence.

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