Published on December 27th, 2012 | by James Ayre4
West Antarctica Warming Twice As Fast As Previously Thought, Research Finds, May Speed Up Sea Level Rise
December 27th, 2012 by James Ayre
New research has revealed that West Antarctica is actually warming nearly two times faster than was previously thought. This finding suggests, therefore, that sea levels may rise much faster than was previously predicted.
The average annual temperatures in West Antarctica, at the Byrd research station, have increased an incredible 2.4 degrees Celsius (4.3F) in the years since the 1950s. This is one of the quickest increases in temperature in the world — it’s currently 3 times the global average increase.
This finding adds strong support to the theory that the ice sheet is much more vulnerable to melting than was previously thought. If West Antarctica was to melt, it would raise global sea levels by at least 3.3 meters (11 feet). It’s currently thought that it would take a few centuries for it to melt completely.
“The western part of the ice sheet is experiencing nearly twice as much warming as previously thought,” Ohio State University said in a recent statement by its geography professor David Bromwich.
The higher than thought warming “raises further concerns about the future contribution of Antarctica to sea level rise,” it said. “Higher summer temperatures raised risks of a surface melt of ice and snow even though most of Antarctica is in a year-round deep freeze.”
Very low-lying countries, such as Bangladesh and many pacific islands, are very vulnerable to near-future levels of sea rise. As are many globally important cities, such as London, New York City, and Buenos Aires. So far, sea levels have increased by about 8 inches in the past hundred or so years.
“The United Nations panel of climate experts projects that sea levels will rise by between 18 and 59 cms (7-24 inches) this century, and by more if a thaw of Greenland and Antarctica accelerates, due to global warming caused by human activities,” Reuters reports.
“The rise in temperatures in the remote region was comparable to that on the Antarctic Peninsula to the north, which snakes up towards South America, according to the U.S.-based experts writing in the journal Nature Geoscience.”
Some glaciated areas of the northern hemisphere have been warming at very significant rates also.
There have been numerous significant collapses of Antarctic ice shelves in the past few years. As these ice shelves collapse and disintegrate, the glaciers that they had previously held in place in the inlands speed up their slide faster into the ocean, which then contributes to sea level rise.
“The stakes would be much higher if a similar event occurred to an ice shelf restraining one of the enormous West Antarctic ice sheet glaciers,” said Andrew Monaghan, a co-author at the U.S. National Center for Atmospheric Research.
The researchers note that there has already been one instance of a very large surface melt of West Antarctica that occurred in 2005. “A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting,” they wrote.
“West Antarctica now contributes about 0.3 mm a year to sea level rise, less than Greenland’s 0.7 mm, Ohio State University said. The bigger East Antarctic ice sheet is less vulnerable to a thaw.
“Helped by computer simulations, the scientists reconstructed a record of temperatures stretching back to 1958 at Byrd, where about a third of the measurements were missing, sometimes because of power failures in the long Antarctic winters.”
Image Credits: NASA; NASA image by Robert Simmon, based on data from Joey Comiso, GSFC
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