Scientists to probe Antarctica for sea rise clues

OSLO (Reuters) - Scientists will visit a vulnerable part of an Antarctic ice shelf this year to work out if it will crack off in coming decades and perhaps trigger a rise in sea levels, they said Thursday.

The scientists, including from the University of Edinburgh and working with the British Antarctic Survey, will drill into the ice and use radars on the Larsen C ice shelf on the Antarctic peninsula, the nearest part to South America.

A chunk of the shelf, Larsen A, broke off in 1995 and another part, Larsen B, in 2002. The remaining Larsen C is about 10 times larger -- about the size of Scotland.

"Scientists are to survey a fragile Antarctic ice shelf to determine what effect its likely collapse could have on global sea levels," the University of Edinburgh said, adding the Larsen C "may collapse within decades."

The experiments could also point to the cause of the Larsen A and B collapses.

The break-up of ice shelves do not directly affect sea level rise because the ice is already floating on the ocean. But past collapses show that inland glaciers often start sliding faster into the sea, adding water and raising ocean levels.

"The glaciers behind the Larsen C are much, much larger" than behind Larsen A and B, said Andrew Shepherd of the University of Edinburgh, one of the experts. "They drain a much larger part of Antarctica.

"Behind the Larsen C, the reservoir of ice is about 20-30 cms (8-12 inches) of global sea level," he told Reuters in a telephone interview.

The U.N. Climate Panel said last year that world sea levels could rise by 18 to 59 cms by 2100, driven by global warming that could also bring more floods, droughts, heatwaves and powerful storms.

The scientists will also see if the shelf was "collapsing because of global warming or whether localized warming is to blame."

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(Editing by Janet Lawrence)