March 25, 2008—New satellite images reveal what scientists call the "runaway" collapse of an enormous ice shelf in Antarctica as the result of global warming. (Read full story.)

The chunk of coastal ice was some 160 square miles (415 square kilometers) in area—about seven times the size of Manhattan.

The shelf's rapid collapse began on February 28 (see image sequence at top right), sending a giant swath of broken ice into the sea—as seen in the bottom image, which shows a 2-mile-wide (3.2-kilometer-wide) area.

"[It's] an event we don't get to see very often," Ted Scambos, lead scientist at the U.S. National Snow and Ice Data Center in Boulder, Colorado, said in a press statement.

"The collapse underscores that the [Wilkins Ice Shelf] region has experienced an intense melt season. Regional sea ice has all but vanished, leaving the ice shelf exposed to the action of waves."

David Vaughan of the British Antarctic Survey noted that the larger formation from which the chunk detached—the Wilkins Ice Shelf—could itself collapse in 15 years.

"Wilkins is the largest ice shelf on West Antarctica yet to be threatened," Vaughan said in the statement. "This shelf is hanging by a thread."

As summer in the Southern Hemisphere draws to a close, further disintegration of the shelf seems unlikely, Scambos added.

"But come January, we'll be watching to see if the Wilkins continues to fall apart," he said.

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