[Anonymous]

Scientists Make Dire Forecast for Alaska
ANCHORAGE,
Alaska (Sept. 07) – 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.The
summer sea ice off Alaska’s north coast will likely shrink considerably
by 2050, said James Overland of the National Oceanic and Atmospheric
Administration. Here, a ship is seen 50 miles north of Point Barrow in
2002.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.
That’s
far past the edge of the highly productive waters over the relatively
shallow continental shelf, considered important habitat for polar bears
and their main prey, ringed seals, as well as other ice-dependent
mammals, such as walrus.The NOAA researchers reviewed 20 computer
scenarios of the effects of warming on sea ice, used by the United
Nations’ Intergovernmental Panel on Climate Change in its assessment
report released this year.The researchers compared those models with
observations from 1979 through 1999, Overland said, and concluded that
the summer ice in the Beaufort Sea likely will have diminished by 40
percent, compared with its 1980s area.The same is likely for the East
Siberian-Chukchi Sea region off northwest Alaska and Russia. In
contrast, Canada’s Baffin Bay and Labrador showed little predicted
change.There was less confidence for winter ice, but the models also
predict a sea ice loss of more than 40 percent for the Bering Sea off
Alaska’s west coast, the Sea of Okhotsk east of Siberia and the Barents
Sea north of Norway.The research paper by Overland and Muyin Wang, a
NOAA meteorologist, will be published Saturday in Geophysical Research
Letters, a publication of the American Geophysical Union.The situation
is dire for polar bears, said Kassie Siegel of the Center for
Biological Diversity, who wrote the petition seeking federal protection
for the animals.’They’re going to drown, they’re going to starve,
they’re going to resort to cannibalism, they’re going to become
extinct,” she said.As ice recedes, many bears will get stuck on land in
summer, where they have virtually no sustainable food source, Siegel
said. Some will try and fail to swim to sea ice, she said.Bears that
stay on sea ice will find water beyond the continental shelf to be less
productive, she said, and females trying to den on land in the fall
will face a long swim.”It’s absolutely horrifying from the polar bear
perspective,” she said.

Less sea ice also will mean a changing ecosystem for commercial fishermen and marine mammals in the Bering Sea, Overland said.With
sea ice present, many of the nutrients produced in the ocean feed
simple plankton that bloom and sink to the ocean floor, providing rich
habitat for crabs, clams and the mammals that feed on them, including
gray whales and walrus.”If you don’t have the ice around, the
productivity stays up closer to the surface of the ocean,” Overland
said. “You actually have a change in the whole ecosystem from one that
depends on the animals that live on the bottom to one that depends on
the animals that live in the water column. So you have winners and
losers.”That could mean short-term gains for salmon and pollock, he
said. But it also could mean that fishermen will have to travel farther
north to fish in Alaska’s productive waters, and warm-water predators
might move north.The contribution to warming by greenhouse gas
emissions likely is set, he said. Emissions stay in the atmosphere for
40 to 50 years before the ocean absorbs them. The amount emitted in the
past 20 years and the carbon dioxide put out in the next 20 will
linger, Overland said.”I’m afraid to say, a lot of the images we are
going to see in the next 30 to 40 years are pretty much already
established,” he said.

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September 10, 2007 at 10:05 AM