Far North Science

Summer hiatus is over. Far North Science returns to discover the sea ice of the Arctic Ocean has shriveled like an ice cube in a pitcher of lukewarm lemonade.

The eye-in-the-sky scientists from the National Snow and Ice Data Center say the far north’s frozen cover — the Earth’s air conditioner — now covers the second smallest area ever recorded during the 30-year-long age of satellites.

“Will 2008 also break the standing record low, set in 2007?,” NSIDC asks in a news release.

“We will know in the next several weeks, when the melt season comes to a close. The bottom line, however, is that the strong negative trend in summertime ice extent characterizing the past decade continues.”

Sea ice typically shrinks in extent and volume during the late summer months, eaten by sun-warmed ocean water and flushed into the Atlantic by currents. But what used to be a slight peeling back of the thick, royal-blue, steel-hard continent of ice off Alaska’s north coast has transformed into a disappearing act.

The result? The coastal residents of Arctic Alaska regularly enter the stormy fall with a vast fetch of ocean at their backs.

Here’s an overview from NSIDC, with an Aug. 27 update:

With several weeks left in the melt season, sea ice extent dipped below the 2005 minimum to stand as the second-lowest in the satellite record. The 2005 minimum, at 5.32 million square kilometers (2.05 million square miles), held the record-low minimum until last year.

Recent ice retreat primarily reflects melt in the Chukchi Sea off the Alaskan coast and the East Siberian Seas off the coast of eastern Russia.

Update 9:15 am MT August 27:

Arctic sea ice extent on August 26 was 5.26 million square kilometers (2.03 million square miles), a decline of 2.06 million square kilometers (795,000 square miles) since the beginning of the month. Extent is now within 430,000 square kilometers (166,000 square miles) of last year’s value on the same date and is 1.97 million square kilometers (760,000 square miles) below the 1979 to 2000 average.

The frozen surface of the Arctic Ocean serves as the hunting platform and resting place for thousands of marine mammals like polar bears, walrus and seals. With so much of the basic summer habitat destroyed, setting the stage for a much reduced winter ice cover, polar bears and other ice-dependent animals will almost certainly find it much harder to find enough to eat.

As a result, the US Fish and Wildlife Service proposed that polar bears be listed as threatened in the United States, due to the inexorable loss of their summer hunting habitat. (More polar bear links here.)

Nine polar bears were spotted swimming miles from land or ice this summer in the open seas north of Alaska, according to this news from the World Wildlife Fund.

“The bottom line here is that polar bears need sea ice, sea ice is decaying, and the bears are in very serious trouble,” longtime Alaska environmental activist Rick Steiner of the University of Alaska’s Marine Advisory Program told the WWF. “For any people who are still non-believers in global warming and the impacts it is having in the Arctic, this should answer their doubts once and for all.”

These latest developments come one year after the 2007 season, when Arctic ice disappeared faster than climate models said was possible. At the time, a NOAA study compared models with observations and concluded the ice free Arctic could be about 30 years off. Other federal scientists reported that most polar bears — including all Alaska populations — would be gone by mid-century.

The retreat of the polar ice cap also poses heartbreaking problems for the people of Alaska villages like Shishmaref and Kivalina. With a fetch of open water stretching 1,000 miles or more, storms can build exceptionally big surf that consumes the barrier islands beneath village homes, tank farms, schools and roads. Lack of thick multi-year ice makes hunting less predictable and more dangerous.