The shifting, grinding ice cap over the Arctic Ocean has shrunk to the smallest extent ever seen by satellites — more than a month before the frozen sea normally stops disintegrating and starts to grow again, according to an analysis by the Polar Research Group at the University of Illinois.
And the summer isn’t over yet.
In a dispatch posted online Aug. 9, the Cryosphere Today reported that “the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history.
“There is still a month or more of melt likely this year,” the scientists added. “It is therefore almost certain that the previous 2005 record will be annihilated by the final 2007 annual minima closer to the end of this summer.”
The ice watchers at the National Snow and Ice Data Center — who share data with the UI team — ramped up their annual Arctic cap web site on Aug. 10. The NSIDC take on the situation was equally grim:
At this point in the 2007 melt season, this much is already clear: the Arctic is experiencing an unprecedented sixth consecutive year with much less sea ice than normal, and it looks like this year’s sea ice melt season may herald a new and steeper rate of decline.
The Arctic melt normally climaxes in late September, when higher temperatures, solar radiation and freshwater flow from rivers reach their summer peak. In 2005, Arctic sea ice had shrunk to a record 2.09 million square miles — more than 40 percent below the long-term average of about 2.97 million square miles for that time of year, according to the National Snow and Ice Data Center.
In September of 2006, the Arctic ice almost matched the record with 2.3 million square miles. Ever since then, the sea ice has either set or flirted with new record minimums for the current month. The failure of the ice pack to rebound during the 2007 winter alarmed scientists and prompted warnings that this summer could see new records.
Arctic sea ice is one of the home planet’s most powerful temperature regulators, providing a sort of global air conditioner that reflects solar radiation back into space and cools the heated air masses that swirl northward from the equator.
It’s also one of the world’s most remarkable ecosystems, home to marine mammals like polar bears, walrus and seals. Fish and algae and plankton converge beneath it and along its edge. It offers Alaska Native and Canadian Inuit hunters a platform for hunting. New ice in the fall can protect coastal villages like Shishmaref from damaging erosion triggered by intense storms.
But the Arctic ice has been disintegrating over the past decade in response to climate change. Some climate models predict that the Arctic will become free of sea ice during summer, threatening ice-dependent species like polar bears with extinction.
Want to put this latest shrinkage in perspective? It’s like a portion of this Arctic habitat as large as Texas and Oklahoma combined simply disappeared from the surface of the planet, according to the NSIDC.
“July 2007 showed the most extreme ice-loss anomaly ever seen since the satellite record began in 1979, with a monthly average extent of only 8.1 million square kilometers (3.13 million square miles),” the NSIDC reported. “This is 900,000 square kilometers (347,492 square miles) below July 2005 — roughly the size of the states of Texas and Oklahoma combined.
“Unless conditions change in an unprecedented way, the Arctic will continue to lose ice for at least another month.”
The New York Times published an article about the reports on Aug. 10 and quoted William Chapman, head of the University of Illinois team:
“The melting rate during June and July this year was simply incredible. … And then you’ve got this exposed black ocean soaking up sunlight and you wonder what, if anything, could cause it to reverse course.”