Topic: Ice bridge ruptures in Antarctic - concerns over the impact of climate change

[Derek]

An ice bridge linking a shelf of ice the size of Jamaica to two islands in Antarctica has snapped.

Scientists say the collapse could mean the Wilkins Ice Shelf is on the brink of breaking away, and provides further evidence or rapid change in the region.

"We know that [the Wilkins Ice Shelf] has been completely or very stable since the 1930s and then it started to retreat in the late 1990s; but we suspect that it's been stable for a very much longer period than that," he told BBC News.

"The fact that it's retreating and now has lost connection with one of its islands is really a strong indication that the warming on the Antarctic is having an effect on yet another ice shelf."

http://news.bbc.co.uk/1/hi/sci/tech/7984054.stm

"During the last year the ice shelf has lost about 1800 square kilometers (694 square miles), or about 14 percent of its size," Humbert said.

Antarctica's ice sheet was formed over thousands of years by accumulated and compacted snow. Along the coast, the ice gradually floats on the sea, forming massive ledges known as ice shelves, the ESA says.

Several of these ice shelves, including seven in the past 20 years, have retreated and disintegrated.

The Wilkins Ice Shelf had been stable for most of the past century before it began retreating in the 1990s.

"It had been there almost unchanged since the first expeditions which mapped it back in the 1930s, so it had a very long period of real stability, and it's only in the last decade that it's started to retreat," Vaughan said.

Wilkins is the size of the state of Connecticut, or about half the area of Scotland. It is the largest ice shelf on the Antarctic Peninsula yet to be threatened.

If the ice shelf breaks away from the peninsula, it will not cause a rise in sea level because it is already floating, scientists say. Some plants and animals may have to adapt to the collapse.

http://edition.cnn.com/2009/TECH/science/04/03/antarctica.ice.shelf/index.html