A vast hunk of floating ice has broken away from the Antarctic peninsula, threatening the collapse of a much larger ice shelf behind it, in a development that has shocked climate scientists.0326 01

Satellite images show that about 160 square miles of the Wilkins ice shelf has been lost since the end of February, leaving the ice interior now "hanging by a thread".

The collapsing shelf suggests that climate change could be forcing change much more quickly than scientists had predicted.

"The ice shelf is hanging by a thread," said Professor David Vaughan of the British Antarctic Survey (BAS). "We'll know in the next few days or weeks what its fate will be."
The Wilkins shelf covers an area of 5,600 square miles (14,500 sq km). It is now protected by just a thin thread of ice between two islands.

Vaughan was a member of the team that predicted in 1993 that global warming could cause the Wilkins shelf to collapse within 30 years.

The shedding of peripheral floating ice shelves has occurred elsewhere on the peninsula, allowing inland ice to move towards the sea and cause rising sea levels.

Some areas of the frozen continent have been cooler in recent years, and have added ice through accumulated snowfall. This year, the thin floating layer of sea ice that forms each austral winter and fades in summer has in fact been larger than usual, in contrast to the Arctic.

But in other parts - such as the West Antarctic ice sheet - ice is being lost to the sea.

The darker area shows the chunk that has broken away. Picture: Nasa Climate scientists around Antarctica were taken by surprise by the new find. "Wilkins is the largest ice shelf on the Antarctic peninsula yet to be threatened," Vaughan said.

Full Story and Video at:
http://www.guardian.co.uk/environment/2008/mar/26/poles.antarctica