Reprint of an Article
By ROBERT BARR
Associated Press Writer

Part of the Larsen B ice shelf after its collapse AP/British Antarctic Survey [21K]

LONDON (AP) — A large Antarctic ice shelf in an area of the giant continent that is warming faster than the global average has collapsed with "staggering'' rapidity, British scientists said Tuesday.

The shelf designated as Larsen B, 650 feet thick and with a surface area of 1,250 square miles, has collapsed into small icebergs and fragments, the British Antarctic Survey said. Before breaking apart, the ice shelf was about the size of Rhode Island.

The ice shelf collapse reported Tuesday was first detected on satellite images earlier this month by Ted Scambos of the National Snow and Ice Data Center at the University of Colorado.

"The reason this is worth paying attention to is that we're seeing a very rapid and profound response by the ice sheet to a warming that's been around for just a few decades,'' Scambos said.

"And we can use this as sort of a guide for what's going to happen if the rest of the Antarctic should begin to warm because of climate change.''

David Vaughan, a glaciologist at the British Antarctic Survey, said the agency predicted three years ago that ice shelves would be disappearing.

"Since then, warming on the peninsula has continued and we watched as piece-by-piece Larsen B has retreated,'' Vaughan said.

"We knew what was left would collapse eventually, but the speed of it is staggering. Hard to believe that 500 million billion tons of ice sheet has disintegrated in less than a month.''

Graphic of Larsen B ice shelf's collapse AP/Ted Scambos [18K]

In recent months, scientists have presented apparently contradictory evidence about warming in Antarctica. Two months ago, the journal Science reported new measurements which indicated that the ice in West Antarctica was thickening, rather than melting.

Scientists are unsure what to make of those measurements, but they are not incompatible with the recently observed ice sheet collapses because they apply to a region much closer to the South Pole than the Antarctic Peninsula.

Referred to as the "banana belt'' by polar scientists, the peninsula is much closer to the equator than is the rest of Antarctica and surrounded on three sides by moderating seas.

In the past half century, the Antarctic Peninsula, which is nearest to southern Argentina and Chile, has warmed by 4.5 degrees Fahrenheit, much faster than average global warming, the Survey said. As a result, five ice shelves which extend out over the ocean along the peninsula have retreated.