Ice chunks float In the Arctic Ocean as the sun sets near Barrow, Alaska, In mid-September

Download 15.05 Kb.
Size15.05 Kb.

The Chronicle Herald


Ice chunks float In the Arctic Ocean as the sun sets near Barrow, Alaska, In mid-September.


Arctic sea ice melting faster than ever, research shows

Trend likely to continue, scientist says

By BOB WEBER The Canadian Press

The ocean area covered by Arctic sea ice last summer was as low as it's ever been, according to a newly released study.

And the rate of melting gets faster ev­ery year, suggesting that a self-perpetu­ating warming cycle predicted by cli­mate change models is already at work, said the data released by the main American centre for ice studies.

"Sea ice is not doing well and it has not recovered and it doesn't appear that it is going to recover," said Mark Serreze of the National Snow and Ice Data Centre in Boulder, Colo.

Global warming is so far having its most dramatic effects in the North, so

Arctic sea ice is considered to be one of the most important indicators of cli­mate change.

The ice also plays an important role in global climate because it affects the delicate balance of ocean salinity and temperature.

As well, it's crucial for everything from polar bears who depend on the floe edge for much of th~ir hunting to shippers on the lookout for more effi­cient routes between ports.

Serreze's group uses data from satel­lites and weather stations to monitor the Arctic ice cap. Every fall, around mid-September, the centre releases a snapshot at the end of the summer melting season of what is called the sea ice minimum.

This year's minimum, which oc­curred Sept. 14, showed the fourth-low­est extent of sea ice on a single day in 29 years of satellite records.

When the entire month of September was considered, the amount of ocean either ice-covered or ice-choked was the second lowest on record. Only 2005

was lower. .

And when only ice-covered ocean was measured, 2006 tied the worst year ever.

"We just ran the numbers this morn­ing," Serreze said Tuesday. "It looks like we're in a dead tie with 2002."

The study also found that the ice is

melting faster than ever.

From 1979 to 2001, Arctic ice shrunk at the rate of 6.5 per cent per decade. Af­ter 2002, that pace rose to 7.3 per cent.

By last year, the world was losing about eight per cent of its ice per dec­ade. Now, the speed is 8.6 per cent.

The accelerating rate conforms with

what scientists call feedback loops.

Dark, open seas absorb the sunlight that white ice would have reflected, so warming speeds up the more ice melts. As well, open seas generate more cloud cover, blanketing the ocean during the long Arctic winter and preventing tem­peratures from falling to normal levels.

"These feedbacks are starting to kick in," said Serreze. "I'm not terribly opti­mistic about the future of the ice."

If current trends hold, Arctic ice will be largely gone by 2060 - a full decade earlier than the most pessimistic previ­ous predictions, he suggested.

Most of the ice losses are concentrat­ed off Russia's Siberian coast.

Winds and currents tend to pW?q, h:e into Canada's High Arctic islands, so coverage there is only shrinking at 1.6 per cent per a decade, said John Fal­kingham, chief forecaster for the Cana­dian Ice Service.

"We expect that the last ice that will remain in the Arctic Ocean will be in Canadian waters," Falkingham said. "The Northwest Passage will be the last place the ice will melt out of."

While ice conditions can vary wildly from year to year, Falkingham said the

overall trend is clear.

"We're seeing decreasing amounts." This September saw the second-low­

est amount of ice in the Canadian Arc­tic; he said. Only 1998 had less.


Share with your friends:

The database is protected by copyright © 2020
send message

    Main page