August 15, 2009 – Original Source: The Times. Valerie Elliott, Countryside Editor
One of Antarctica’s largest glaciers is thinning four times faster than thought ten years ago, it has been found.
Satellite records show that if the melting of the Pine Island Glacier in west Antarctica goes on accelerating at current rates, the main section will have disappeared in 100 years, 500 years sooner than previously thought.
The research showed that the ice surface is dropping at a rate of 16m a year.The faster melting affects 5,400sq km of the glacier, containing enough water to raise world sea levels by 3cm, said Professor Andrew Shepherd of the University of Leeds, a member of the research team.
The glacier’s melting could also expose stationary ice behind it to warm seawater, and if that ice were to melt, it could raise sea levels by another 25cm.
The research, led by Professor Duncan Wingham at University College London and published in Geophysical Research Letters, is based on satellite observations of the glacier over 15 years.
Professor Shepherd said: “Being able to assemble a continuous record of measurements over the past 15 years has provided us with the remarkable ability to identify both subtle and dramatic changes in ice that were previously hidden.
“Because the Pine Island Glacier contains enough ice to almost double the Intergovernmental Panel on Climate Change’s best estimate of 21st-century sea level rise, the manner in which the glacier will respond to the accelerated thinning is a matter of great concern.”
Professor Shepherd said: “This is unprecedented in this area of Antarctica. We’ve known that it’s been out of balance for some time, but nothing in the natural world is lost at an accelerating exponential rate like this.”
Scientists also report evidence of a dramatic loss of sea ice in the Arctic. Professor Jason Box, of Ohio State University, has found much less sea ice than expected in the Nares Strait between Greenland and Canada.
He said: “The science community has been surprised by how sensitive these large glaciers are to climate warming. First it was the glaciers in south Greenland and now as we move farther north in Greenland we find retreat at major glaciers.
“It’s like removing a cork from a bottle.”