During the week when federal scientists predicted two-thirds of all polar bears would die out within decades due to shrinking summer ice cover, the Arctic cap continued the astounding meltdown into record territory.
By Sept. 10, Arctic ice covered only 1.63 million square miles — the smallest extent ever recorded by satellite and far smaller than any estimate of ice cover in historic times. The area with at least 15 percent ice was about 20 percent smaller than the previous all-time minimum record of 2.05 million square miles observed on Sept. 21-22, 2005.
The climate gurus at the National Snow and Ice Data Center offer this perspective in their latest update on the fall slush bowl:
A specific area of the Arctic Ocean as large as California is now ice free for the first time in history.
The only good news here may be that the melt rate has slowed. Only 70,000 square miles disappeared between Sept. 4 and Sept. 10 — an area about the size of Missouri. The week before, the Arctic lost a Montana’s worth of frozen floes.
The latest details on the most extreme polar melt of historic times can be found at the fall ice season news site by the National Snow and Ice Data Center.
The shrinkage of the home planet’s air conditioner — cooling air from the tropics and reflecting heat back into space — poses existential threats to marine mammals and Native people trying to maintain hunting traditions.
Polar bears, seals and walrus need the ice as hunting and resting platforms. Its elimination destroys their essential habitat. With such an unprecedented fetch to the northwest, Alaska coastal villages like Shishmaref and Kivalina may remain exposed to high surf and storm erosion late into the fall, the season of Alaska’s strongest storms. This could be the year that the villages call for evacuation.
With the rate of ice loss slowing, the year’s minimum extent could occur any time over the next two weeks, according to NSIDC. “While on average, based on data from 1979 to 2000, this minimum has occurred around September 13, it has occurred as late as September 25,” the update reported.
The new dispatch offers some intriguing graphics and discussion about how a slug of warm water oozed into the Arctic Ocean from the Atlantic, reached the seas north of the Russian Far East and Alaska, and continued to release warmth into the air. A chart shows anomalous warmth over the Chukchi Sea and Alaska.
But the most disturbing analysis centers on the graphic appearing to the right. Here’s what the NSIDC dispatch says:
In this figure, we overlay two areas.
Gray areas within the Arctic Ocean indicate where sea ice was present every day of every year from 1979 through spring 2007.
Yesterday’s sea ice is in white, and the overlap areas are in light gray.
The dark gray color represents the region that is ice-free for the first time in the satellite record.
What does this figure really tell us? It tells us that a large area is, for the first time since the satellite record began, not covered by sea ice.
The amount and location of summer sea ice varies from year to year, so even after twenty-eight years it would not be surprising to have some small areas that are newly ice-free each year.
However, this year the first-time ice-free area is extremely large — roughly the size of the state of California.
[...] Polar ice shrinks further [...]
[...] Polar ice shrinks further [...]
[...] Polar ice shrinks further [...]