The flow of warm water from the ocean's depths via two previously unnoticed "pathways" appears to be behind the extreme thinning of East Antarctica's Totten Glacier, researchers say. The discovery, reported in Nature Geoscience, heightens concern about the long-term prospects for the Antarctic ice sheet.
Scientists previously knew it was possible for warmer, saltier water to lie beneath colder water off the coast of Antarctica. The newly published study found that the warmer water was moving up through wide troughs on the seafloor toward the coastline, where it could melt the glacier's ice from below. Researchers mapped the topography from the air, using ice-penetrating radar, laser altimeters and other instruments.
“We now know there are avenues for the warmest waters in East Antarctica to access the most sensitive areas of Totten Glacier,” study lead author Jamin Greenbaum, a researcher at the University of Texas at Austin’s Institute for Geophysics, said in a news release.
Similar processes are thinning the ice in West Antarctica, but Totten Glacier's thinning in East Antarctica adds to concerns about a long-term thaw. If the glacier were to collapse completely, global sea levels would rise by at least 11 feet (3.4 meters), the researchers said. However, it would take many centuries for such a meltdown to occur.
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— Alan Boyle
In addition to Greenbaum, the authors of "Ocean Access to a Cavity Beneath Totten Glacier in East Antarctica" include D.D. Blankenship, D.A. Young, T.G. Richter, J.L. Roberts, A.R.A. Aitken, B. Legresy, D.M. Schroeder, R.C. Warner, T.D. van Ommen and M. J. Siegert.