Scott PRI Study: Antarctic Ice Sheets Capable Of Retreating At Six Miles Per Year
Climate researchers racing to calculate how fast and how high the sea level will rise found new clues on the seafloor around Antarctica. A study released today suggests that some of the continent's floating ice shelves can, during eras of rapid warming, melt back by six miles per year, far faster than any ice retreat observed by satellites. As global warming speeds up the Antarctic meltdown, the findings "set a new upper limit for what the worst-case might be," said lead author Julian Dowdeswell, director of the Scott Polar Research Institute at the University of Cambridge.
The estimate of ice shelf retreat is based on a pattern of ridges discovered on the seafloor near the Larsen Ice Shelf. The spacing and size of the ridges suggest they were created as the floating ice shelves rose and fell with the tides while rapidly shrinking back from the ocean. In findings published today in Science, the researchers estimate that to corrugate the seafloor in this way, the ice would have retreated by more than 150 feet per day for at least 90 days.
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If the rate of retreat estimated by the new study extended across an 18-mile-wide and half-mile-thick ice shelf, as found in the closely watched Pine Island Glacier in West Antarctica, the researchers calculated it would release 138-gigatons of ice per year— three to five times more ice than is currently lost annually from that glacier system. Sea level rise can't be directly extrapolated from the rate of ice shelf retreat, said University of Liège ice researcher Xavier Fettweis, but the results of the new study suggest it could accelerate in coming decades.
"With such retreat rates, the sea level rise contribution from Antarctica could be a lot higher and quicker than expected, as the models are tuned to represent the current observed retreat rates," he said. Currently, the fastest retreat rates are more than half a mile per year for the ice shelves extending from the Pine Island and Thwaites glaciers, and 1.2 miles per year for the one below the Smith Glacier, which is also in West Antarctica.
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https://insideclimatenews.org/news/28052020/antarctic-ocean-ice-melt-climate-change
Link to Scott Polar Research Institute Study (subscription):
https://science.sciencemag.org/content/368/6494/1020
