NASA study: Net gains for Antarctic ice sheets

The gains came in the form of ice thickening -- thickening researchers have previously dismissed as snow accumulations.
By Brooks Hays  |  Oct. 31, 2015 at 5:00 PM
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GREENBELT, Md., Oct. 31 (UPI) -- According to a new NASA study, ice sheet gains outweigh losses on the Antarctic continent. The findings conflict with those of the Intergovernmental Panel on Climate Change, which in 2013 suggested gains were not keeping up with losses.

The new study, published in the Journal of Glaciology, doesn't totally undermine the handful of studies showing significant glacier, ice sheet and sea ice shrinkage. Instead, if offers evidence of previously unaccounted gains.

The new tallies reveal an annual net gain of 112 billion tons between 1992 and 2001. Annual gains of 82 billion tons were observed between 2003 and 2008.

"We're essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica," lead study author Jay Zwally, a glaciologist with NASA Goddard Space Flight Center, said in a press release. "Our main disagreement is for East Antarctica and the interior of West Antarctica -- there, we see an ice gain that exceeds the losses in the other areas."

Zwally says the satellite measurements he and his colleagues analyzed reveal "small height changes over large areas, as well as the large changes observed over smaller areas."

The gains came in the form of ice thickening -- thickening researchers have previously dismissed as snow accumulations. But Zwally's study looked at meteorological records to show that snow accumulations have actually dropped off over the last two decades. He and his colleagues also looked at historical meteorological data gleaned from ice cores, and found that snowfall from 10,000 years ago has been slowly compacted and turned into ice over the last several millennia.

The new findings may force scientists to rethink models that attempt to account for sea level rise.

"The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away," Zwally said. "But this is also bad news. If the 0.27 millimeters per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for."

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