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Sea Ice Decline
The U.S. Fish and Wildlife Service was petitioned to list the polar bear as a threatened species pursuant to the Endangered Species Act primarily because of the decline of its primary habitat: sea ice.

The last four years have been the four lowest years on record of Arctic summer sea ice since satellite monitoring started in 1979.

The 2008 minimum is consistent with the continued rapid decline in summer sea ice in the Arctic that has been evident since satellite records started in 1979.

Unfortunately, the long term Arctic summer sea ice decline, including the 2008 melt, verify that determination of the polar bear to be a threatened species was the correct action.

Rapid Arctic ice melting has continued in 2008, and is very near to the 2007 all-time record low for the extent of summer sea ice in the Arctic Ocean. The 2007 low was nearly 23% below the previous record low in 2005. The size of the increase in summer ice melt for each year of 2007 and 2008, compared to average sea ice conditions, was equivalent in area to the size of Alaska and Texas, combined.

The actual sea ice decline is outpacing the projections of most climate-ice models. Based on the rapid melt, one NASA scientist has projected summer ice could be essentially gone by as early as 2012.

Sea Ice Loss and Polar Bears
The loss of Arctic sea ice has huge implications for polar bears. U.S. Geological Survey studies and models indicate that two thirds of polar bears will disappear by 2050, due to ice loss. The retreat of ice has implications beyond the obvious outright loss of their habitat. Remaining ice may not be as suitable for polar bears because of its much greater distance from shore, making it less accessible. The larger gap of open water between the ice and land also contributes to rougher wave conditions. In 2004, biologists discovered four drowned polar bears in the Beaufort Sea, and suspect the actual number of drowned bears may have been considerably greater. Never before observed, biologists attributed the drowning to a combination of retreating ice and rougher seas, which made swimming from shore to sea ice more hazardous. Because of the retreating ice, polar bears are going hungry for longer periods of time. As result, in ! the past several years biologists have observed acts of cannibalism among polar bears. Although it has long been known that polar bears will occasionally kill other polar bears for dominance or kill cubs so they can breed with the female, outright predation for food was previously unknown.

Exacerbating the problems of the loss of an icy platform from which to hunt seals, it is expected that the shrinking polar ice cap will also adversely affect their primary prey—seals. Because of the reduction in ice platforms near productive areas for the fish that the seals eat, their nutritional status and productivity are declining.

More on polar bears