Antarctic ice tells conflicting story about climate change's role in big melt
Researchers have a keen interest in trying to understand and project ice losses in Antarctica, as well as on Greenland, with global warming. Previous studies have shown that since 1992, the loss of ice from polar caps is raising sea levels by an average of about 0.59 millimeters a year.
The West Antarctic Ice Sheet alone could boost sea levels an average of 10 feet if it melts – an increase that would occur over hundreds to thousands of years, notes Eric Steig, a researcher at the University of Washington who led one of the two research efforts.
Between 1992 and 2011, the peninsula lost ice at rate of 20 billion tons a year, according to a study published last November in the journal Science. The West Antarctic Ice Sheet lost 65 billion tons a year, and the East Antarctic Ice Sheet – the continent's largest – lost 14 billion tons a year, although the uncertainties in that number are so large the loss could just as well have been nothing.
The Antarctic Peninsula is an extended arm of land that last shook hands with the southern tip of South America roughly 235 million years ago when the two continents drifted apart. It's mountainous and extends into the Southern Ocean to some 250 miles above the Antarctic Circle.
"In some ways, it's a climate oddity," writes Robert Mulvaney, a researcher with the British Antarctic Survey (BAS) and a member of the team formally reporting its results on the region's ice Sunday in the journal Nature Geoscience, in an e-mail. Relatively warm westerly winds, laden with with ocean moisture, blow across the peninsula. So it tends to be warmer than the mainland and experiences higher snowfall rates.