Why Second Place Matters, When It Comes to Arctic Sea Ice

Arctic sea ice extent, as of Sept. 15, 2008. The orange line shows the longterm average extent.

Photo: NSIDC

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The Arctic has begun to re-freeze, its sea ice having reached its lowest extent Sept. 12, the National Snow and Ice Data Center reported Tuesday.

The headlines all note that this is the second-greatest melt ever witnessed in the Arctic -- 860,000 square miles more ice melted than has in an average summer.

And that's the real story: We're out of "normal" range. Way out.

Arctic sea ice melts every summer, and each winter it re-freezes. That's normal. But the degree of melting witnessed in recent years is not, and scientists say it's an early and dramatic indicator that global warming is real, it is here, and it will not go away on its own. To the contrary, it will feed on itself, as it does in the Arctic: as reflective ice melts, the darker freshly exposed waters absorb more heat, contributing to more melting of the world's air conditioner.

In 2005, a new record for sea ice melting was set, and alarm bells went off. Then, last year, the 2005 record was obliterated. Now, the melting did not quite reach the extent seen in 2007, but it is still well beyond what was witnessed in 2005, and way beyond the average from 1979-2000, since satellite measurements began -- 33% below average.

Put another way, so much additional ice melted that the ice would cover Alaska, Texas, and West Virginia combined, according to WWF math. Put yet another way, in the words of NASA: "This perennial ice used to cover 50-60% of the Arctic, but this winter it covered less than 30%."

The rapid melt poses an existential threat to Arctic wildlife, like the polar bear, walrus and several penguin species. It's a reminder that global warming, left unabated, will pose an existential threat to many more species, including more than a little discomfort for us.

So, yes, second place matters.

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