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article imageWest Antarctic ice sheet collapsing

By Karen Graham     May 12, 2014 in Environment
A massive glacier system has started collapsing in West Antarctica due to global warming, and studies by two different teams of scientists claim the collapse will result in a significant rise in sea levels worldwide.
A slow-motion disaster may be unfolding according to two different teams of scientists. The scientists reported earlier this week that the Thwaites Glacier, which acts as a keystone holding back the massive West Antarctic Ice Sheet is starting to collapse. According to the reports, the entire ice sheet is doomed to collapse, raising sea levels worldwide by as much as four feet or more.
In an article published online today in Science, one team combined recent data on the receding 182,000-square-kilometer Thwaites Glacier with computer modeling of the glacier's dynamics to forecast future movement.
Crevasses are seen in the Thwaites glacier on October 16  2012.
Crevasses are seen in the Thwaites glacier on October 16, 2012.
NASA/JAMES YUNGEL, NASA
Ian Joughin, who studies glaciers at the University of Washington, Seattle, and one of the co-authors of this study says it was thought the Thwaites Glacier was "stabilized for a few thousand years." "what we have shown is this glacier is really in the early stages of collapse," he added.
Joughin and his colleagues estimate it will take from 200 to 900 years for the process to be completed, depending on how much temperatures rise and how much snow falls in the region.
The second team, writing in Geophysical Research Letters (GRL), was lead by Eric Rignot, a climate scientist at the University of California, Irvine, This team confirmed the findings of the Joughlin team, reporting recent radar mapping of West Antarctica’s glaciers shows there is a 600-meter-deep ridge as the final obstacle before the bedrock underlying the glacier slips into a deep basin.
Icebergs that appear to have broken off Thwaites glacier spread across Pine Island Bay.
Icebergs that appear to have broken off Thwaites glacier spread across Pine Island Bay.
NASA
Because the Thwaites Glacier connects with other major glaciers in the area via the inland basin, a collapse would flood West Antarctica with seawater, creating a near-total loss of ice in the area. In simple terms, the Thwaites Glacier is acting like a plug, holding everything together. “The next stable state for the West Antarctic Ice Sheet might be no ice sheet at all,” says Joughlin.
Richard Alley, a professor of Earth sciences at Penn State University in State College, Pennsylvania, and not a member of either team of researchers, had this to say: “Very crudely, we are now committed to global sea level rise equivalent to a permanent Hurricane Sandy storm surge,” referring to the storm that hit the Eastern Coast of the United States in 2012.
Alley says the data from Rignot's group is consistent with the computer modeling by Joughin's group, "But these results are sobering," he says, "even the possibility that we have already committed to three-plus meters of sea-level rise from West Antarctica will be disquieting to many people, even if the rise waits centuries before arriving."
Scientists have always thought there was a sill, or ridge of bedrock, a vertical formation of rock under the ocean acting as a wall, holding back the glacier. The new studies confirm this is not the case, but instead, the melting ice has "greased" its way over the rock ridge.
More about Thwaites glacier, West Antarctic Ice Sheet, Sea level rise, unstoppable, Global warming