Arctic ice melting at record rate*

By Amanda Beck San Francisco

December 13, 2007 02:35pm
Article from: Agence France-Presse

ARCTIC ice at the North Pole melted at a record rate in the northern
hemisphere summer, the latest sign that climate change has accelerated
in recent years, climate scientists say.

"In 2007, we had off the charts warming," Michael Steele, an
oceanographer at the University of Washington, said at the 2007 meeting
of the American Geophysical Union, where 15,000 researchers have
gathered to discuss earthquakes, water resources, and climate change.

It was an ominous summer for the Arctic region, where for the first time
in recorded history, ships sailed across the Arctic Ocean in water that
had been part of the polar icecap, said Donald Perovich of the US Army
Cold Regions Research and Engineering Laboratory in New Hampshire.

In the northern summer of 1980 the North Pole was covered by an ice
sheet about the size of the continental United States, but this summer
the ice would not have covered the states west of the Mississippi River,
he said.

"It's a tremendous decrease, but of course, the mystery is how did it
happen?" Mr Perovich said.

Scientists said two principal factors were accelerating the vanishing of
the polar icepack, which helps cool the Earth by reflecting the sun's
rays back into the atmosphere.

As temperatures in the Pacific and Atlantic Oceans rose, warmer water
moved into the Arctic Ocean.

This helped melt the polar icecap, which this year floated in water
about 3.5C warmer than its historical mean, Mr Steele said.

"Water that is now circulating just 200m below the main icepack is now
significantly warmer than it was just five years ago," said John Walsh
of the University of Alaska.

As ice in the arctic melts to water, it also reflects only 7 per cent of
the sun's radiation, much less than the 85 per cent that ice normally
reflects.

As more of the Arctic Ocean was exposed, it absorbed these extra sun
rays, further hastening the planet's rising temperature, Mr Perovich said.

"It's a classic positive feedback. And these feedbacks are important
from a climate perspective, because they can take small changes and
amplify them," he said.

He said people near the Arctic Circle were already seeing some of the
effects of polar warming.

Companies were starting to explore for natural resources in newly
exposed areas, and coastal villages were grappling with erosion as sea
levels rise.

The scientists also expressed scepticism about humans' ability to help
generate a cold winter soon enough that could allow the icecap to refreeze.

New research shows that carbon dioxide, one gas that traps heat in the
atmosphere, can be captured as it leaves coalburning power plants and
then permanently sequestered in rock formations thousands of feet below
the Earth's surface.

However, it will be about 10 years before the first of such plants comes
online, said Julianna Fessenden of the Los Alamos National Laboratory.

"It's basically the fourth quarter, and we're down two touchdowns," Mr
Perovich said.

"As you go farther down this (global warming) path, it becomes harder to
come back."