Going, Going, Gone: Ice & the Climate

Sea ice in the Arctic has failed to re-form for the second consecutive winter, raising fears that global warming may have tipped the polar regions in to irreversible climate change far sooner than predicted.

Satellite measurements of the area of the Arctic covered by sea ice show that for every month this winter, the ice failed to return even to its long-term average rate of decline. It is the second consecutive winter that the sea ice has not managed to re-form enough to compensate for the unprecedented melting seen during the past few summers.

Scientists are now convinced that Arctic sea ice is showing signs of both a winter and a summer decline that could indicate a major acceleration in its long-term rate of disappearance. The greatest fear is that an environmental “positive feedback” has kicked in, where global warming melts ice which in itself causes the seas to warm still further as more sunlight is absorbed by a dark ocean rather than being reflected by white ice.

You can read the complete article here. In response, Stuart Staniford writes on the blog The Oildrum that he’s more skeptical, finding the Independent article alarmist. The ensuing discussion (there are 74 comments so far!) is fascinating. Staniford also locates an excellent website, Cryosphere Today which monitors sea ice coverage (the pix above comes from that site.) As I’m writing this, friend Wiliam Prescott, commenting that “this is just the first weak version of this kind of analys” sent the following Reuters report, which can be found in full here:

Global warming reaches ‘tipping point’ – report

16 March 2006

WASHINGTON: Human-fueled global warming has reached a “tipping point,” according to a new survey of scientific research that found warming would continue even if greenhouse gas emissions halted immediately.

“It would keep on warming even though we have stopped the cause, which is greenhouse gases from the combustion of fossil fuels,” David Jhirad of the Washington-based World Resources Institute said on Wednesday.

The rate of warming would be slower, Jhirad said in a telephone interview, but a kind of thermal inertia would ensure that global temperatures continue their upward trend.

He referred to a report released by the nonprofit institute this week that analysed research reports on climate change for 2005.

“Taken collectively, they suggest that the world may well have moved past a key physical tipping point,” the institute wrote.