Mon Jan 19, 2009 4:14pm EST
19 Jan 2009
19 Jan 2009
By Alister Doyle, Environment Correspondent
WILKINS ICE SHELF, Antarctica (Reuters) - A huge Antarctic ice shelf is on the brink of collapse with just a sliver of ice holding it in place, the latest victim of global warming that is altering maps of the frozen continent.
"We've come to the Wilkins Ice Shelf to see its final death throes," David Vaughan, a glaciologist at the British Antarctic Survey (BAS), told Reuters after the first -- and probably last -- plane landed near the narrowest part of the ice.
The flat-topped shelf has an area of thousands of square kilometers, jutting 20 meters (65 ft) out of the sea off the
But it is held together only by an ever-thinning 40-km (25-mile) strip of ice that has eroded to an hour-glass shape just 500 meters wide at its narrowest.
In 1950, the strip was almost 100 km wide.
"It really could go at any minute,"
The Wilkins once covered 16,000 sq km (6,000 sq miles). It has lost a third of its area but is still about the size of
Icebergs the shape and size of shopping malls already dot the sea around the shelf as it disintegrates. Seals bask in the southern hemisphere summer sunshine on icebergs by expanses of open water.
A year ago, BAS said the Wilkins was "hanging by a thread" after an aerial survey. "Miraculously we've come back a summer later and it's still here. If it was hanging by a thread last year, it's hanging by a filament this year,"
Nine other shelves have receded or collapsed around the
WARMING TO BLAME
"This ice shelf and the nine other shelves that we have seen with a similar trajectory are a consequence of warming,"
In total, about 25,000 sq km of ice shelves have been lost, changing maps of
The shelf is named after Australian George Hubert Wilkins, an early Antarctic aviator who is set to join an exclusive club of people who have a part of the globe named after them that later vanishes.
Loss of ice shelves does not raise sea levels significantly because the ice is floating and already mostly submerged by the ocean. But the big worry is that their loss will allow ice sheets on land to move faster, adding extra water to the seas.
Wilkins has almost no pent-up glaciers behind it. But ice shelves further south hold back vast volumes of ice. "When those are removed the glaciers will flow faster,"
Temperatures on the
BAS scientists and two Reuters reporters stayed about an hour on the shelf at a point about 2 km wide.
"It's very unlikely that our presence here is enough to initiate any cracks,"
The U.N. Climate Panel, of which Vaughan is a senior member, projected in 2007 that world sea levels were likely to rise by between 18 and 59 cm (7 and 23 inches) this century.
But it did not factor in any possible acceleration of ice loss from
About 190 nations have agreed to work out a new U.N. treaty by the end of 2009 to slow global warming, reining in emissions from burning fossil fuels in power plants, cars and factories.
(Editing by Andrew Roche)
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