Melting

Associated Press:

An analysis of 20 years' worth of real-life observations supports recent U.N. computer predictions that by 2050, summer sea ice off Alaska's north coast will probably shrink to nearly half the area it covered in the 1980s, federal scientists say.

Such a loss could have profound effects on mammals dependent on the sea ice, such as polar bears, now being considered for threatened species status because of changes in habitat due to global warming. It could also threaten the catch of fishermen.

In the 1980s, sea ice receded 30 to 50 miles each summer off the north coast, said James Overland, a Seattle-based oceanographer for the National Oceanic and Atmospheric Administration.

"Now we're talking about 300 to 500 miles north of Alaska," he said of projections for 2050.