Warm Water Invasion Is Fueling Striking Antarctic Ice Melt

The tongues of ice that stick out from and help to buttress the frozen expanse of Antarctica are increasingly under assault from warm ocean waters invading from below, potentially impacting global sea level rise a new study says.

That warm water intrusion eats away at the parts of Antarctica’s glaciers that flow into and float atop coastal waters.  Called ice shelves, these slabs of ice help to hold back the glaciers that flow into them.  When the ice shelves melt away or crumble, the glaciers can speed up, dumping more currently land-bound ice into the seas and raising global sea levels.  The new study, detailed in the Dec. 5 issue of the journal Science, shows how and where the warm water intrusion is happening around the continent and other areas where it could soon begin.

“It really does answer what was sort of an unanswered question,” said Sarah Gille, an oceanographer at the Scripps Institution of Oceanography in La Jolla, Calif., who was not involved with the study.  Gille wrote a review of the work in the same Science issue.

One of the areas of Antarctica that has seen the most warm water seeping in is unsurprisingly one of the fastest-melting parts of the continent and the biggest Antarctic contributor to current sea level rise. Its rate of melt has tripled over just the past decade, separate research accepted to the journal Geophysical Research Letters concludes.

‘In the Dark’
While Antarctica is one of the most remote places on the planet, the fate of its ice is of major concern because of its potential to drastically raise global sea levels as it melts. The West Antarctic Ice Sheet alone (the area where the fastest melting glaciers are) holds enough ice to raise the oceans by 10 to 13 feet, though even partial melting could cause substantial sea level rise.  “But other parts of Antarctica have way more ice,” said the lead author of the Science study, Sunke Schmidtko, of the University of East Anglia and the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany.

Research published earlier this year found that several of the glaciers of the Amundsen Sea Embayment in West Antarctica were retreating at a record pace and that pace had accelerated in recent decades.  “The retreat of ice in that sector is unstoppable,” lead researcher Eric Rignot, a glaciologist at the University of California, Irvine, and NASA’s Jet Propulsion Laboratory, said when the study was published.

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