Washington, Dec 24 (IANS) The western part of the Antarctica ice sheet is experiencing nearly twice as much warming as previously thought, raising concerns about its contribution to rising sea levels.
The temperature record from Byrd Station, a scientific outpost in the centre of the West Antarctic Ice Sheet (WAIS), demonstrates a marked increase of 4.3 degrees Fahrenheit (2.4 degrees Celsius) in average annual temperature since 1958 - that is, three times faster than the average temperature rise around the globe.
This temperature increase is nearly double what previous research has suggested, and reveals - for the first time - warming trends during the summer months of the Southern Hemisphere (December through February), said David Bromwich, professor of geography at Ohio State University and senior research scientist at the Byrd Polar Research Centre.
"Our record suggests that continued summer warming in West Antarctica could upset the surface mass balance of the ice sheet, so that the region could make an even bigger contribution to sea level rise than it already does," said Bromwich, the journal Nature Geoscience reports.
"Even without generating significant mass loss directly, surface melting on the WAIS could contribute to sea level indirectly, by weakening the West Antarctic ice shelves that restrain the region's natural ice flow into the ocean," added Bromwich, according to an Ohio statement.
Andrew Monaghan, study co-author and scientist at the National Center for Atmospheric Research (NCAR), said that these findings place West Antarctica among the fastest-warming regions on Earth.
"We've already seen enhanced surface melting contribute to the break-up of the Antarctic's Larsen B Ice Shelf, where glaciers at the edge discharged massive sections of ice into the ocean that contributed to sea level rise," Monaghan said. "The stakes would be much higher if a similar event occurred to an ice shelf restraining one of the enormous WAIS glaciers."