Ice flow to ocean offsetting Antarctica's ice gain: Study
A new study shows that a lot of the ice gain in the Antarctic ice sheet due to increased snowfall triggered by climate change is balanced by an acceleration of ice flow to the ocean.
Global warming leads to more precipitation as warmer air holds more moisture - hence earlier research suggested the Antarctic ice sheet might grow under climate change.
A research team from the Potsdam Institute for Climate Impact Research (PIK), however, suggests that Antarctica's contribution to global sea-level rise is probably greater than hitherto estimated.
"Between 30 and 65 percent of the ice gain due to enhanced snowfall in Antarctica is countervailed by enhanced ice loss along the coastline," says PIK's Ricarda Winkelmann, who led the study, the journal Nature reports.
For the first time, an ensemble of ice-physics simulations shows that future ice discharge has increased up to three times because of additional precipitation in Antarctica under global warming.
"The effect exceeds that of surface warming as well as that of basal ice-shelf melting," Winkelmann says, according to a PIK statement.
During the last decade, the Antarctic ice sheet has lost volume at a rate comparable to that of Greenland. "The one certainty we have about Antarctica under global warming is that snowfall will increase," Winkelmann explains.
"Since surface melt might remain comparably small even under strong global warming, because Antarctica will still be a pretty chilly place, the big question is: How much more mass within the ice sheet will slowly but inexorably flow off Antarctica and contribute to sea-level rise, which is one of the major impacts of climate change," says Winkelmann.
"We now know that snowfall in Antarctica will not save us from sea-level rise," says Anders Levermann, research domain co-chair at PIK and a lead author of the sea-level change chapter of the upcoming fifth assessment report of the Intergovernmental Panel on Climate Change.