West Antarctic ice shelf collapsed during warming event 125,000 years ago
By Alister Doyle, Reuters
Wednesday, 1 September 2010 Tiny marine creatures found on the seabed on opposite sides of West Antarctic give a strong hint of the effects of sea level rise, say scientists. The discovery of very similar colonies of bryozoans, animals that anchor themselves to the seabed, in both the Ross and Weddell Seas are a clue that the ice sheet once thawed and the seas were once linked, they say. West Antarctica holds enough ice to raise world sea levels by between 3.5 and 5 metres if the sheet collapsed. Some scientists believe it may have vanished during a natural warm period within the last few hundred thousand years. “It was a very big surprise,” says David Barnes, lead author of the study at the British Antarctic Survey, of the find of similar bryozoans 2400 kilometres apart in seas on either side of the West Antarctic ice sheet, which is 2 kilometres thick. “The most likely explanation of such similarity is that this ice sheet is much less stable than previously thought and has collapsed at some point in the recent past,” he says. “And if the West Antarctic ice shelf has been lost in recent times we have to re-think the possibility of loss in future with climate change.” …
