Arctic Ocean sea ice – one of the most visible indicators for global warming – may be headed for another record-breaking summer decline.
If the pattern continues, new research suggests, its warming effect could reach up to 900 miles inland, melting permafrost and potentially altering weather patterns at lower latitudes.
As of June 7, preliminary data show that the vast expanse of ice at the top of the world is some 55,800 square miles smaller than it was on the same date last year, according to University of Colorado researcher Sheldon Drobot. In May, sea-ice extent was slightly large than in May 2007. But the melt rate during the month – some 3,000 square miles a day – was faster, according to the National Snow and Ice Data Center in Boulder, Colo.
The ice’s seasonal shrinkage in 2007 smashed records, reaching a September minimum of 2.6 million square miles – some 23 percent smaller than the previous record, set in 2005. If it sets another record this year, it would mark the fifth season of record declines since 1998. “The next few weeks should be quite instructive, and by mid July we ought to have a very good sense of how things are shaping up,” says Dr. Drobot, who is using satellite data on ice extent to develop forecasts of seasonal changes in Arctic Ocean ice cover.
EDIT
The seawater retained enough residual heat, in fact, to significantly slow the freeze-up of sea ice heading into last winter. The intensity of this classic “ice-albedo feedback” may be one reason why the Arctic is responding so much faster to global warming than many climate models had projected, he says. The results appeared in the June 3 issue of Geophysical Research Letters. The question now: “We see this big drop; are we going to hit a plateau and bounce around for a while or are we in free-fall?” he asks. It’s a question whose answer may have implications well below the Arctic Circle. High-latitude warming – when reinforced by a five- to 10-year period of sudden, deep sea-ice meltbacks – could be 3.5 times higher than climate models typically project, according to a study published this week and prompted by last year’s sea-ice meltdown. Moreover, the added warmth extends as far as 900 miles deep into the North American and Eurasian continents.
EDIT
http://features.csmonitor.com/environment/2008/06/12/arctic-sea-ice-melting-faster-than-expected/
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
