West Antarctic's Melting Plugs May Trigger 3-Meter Rise in Seas

  • Melting of continetal ice sheet may be `unstoppable' process
  • `Vicious cycle of retreating continental ice would kick in'

Ice shelves in the Amundsen Basin area of Antarctica have become destabilized by warming seawater, a shift that may accelerate melting of the West Antarctic ice sheet and drive up sea levels, according to a new study. 

Those shelves protect the continental ice sheet. If they melt, it would trigger an “unstoppable” process and the “huge West Antarctic ice sheet would collapse completely,” scientists at the Potsdam Institute for Climate Impact Research said in a paper published Monday in the Proceedings of the National Academy of Science.

“In our simulations, 60 years of melting at the presently observed rate are enough to launch a process which is then unstoppable and goes on for thousands of years,” Johannes Feldmann, the lead author, said in an e-mailed statement. “What we call the eternal ice of Antarctica unfortunately turns out not to be eternal at all.”

“This would eventually yield at least 3 meters (9.8 feet) of sea-level rise, ” he said. “This certainly is a long process. But it’s likely starting right now.”

While the tongue of glacial ice in the Amundsen Basin is perhaps only 1 percent of the area of the western icecap, it acts “like a plug,” Anders Leverson, a co-author, said in a phone interview. “If the plug disappears a vicious cycle of retreating continental ice would kick in over thousands of years, depleting the icecap of the Western Antarctic.”

The scientists said that warming ocean waters beneath the Amundsen Basin ice are melting that plug. While they didn’t study the cause of the warming water and therefore couldn’t conclude its due to climate change, “it’s curious that Amundsen has been stable for the last 10,000 years,” Leverson said.

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