Thwaites Glacier is warmed from all sides
The Thwaites Glacier in West Antarctica is one of the most studied glacier systems in the southern hemisphere. This is due to both its size and the rate at which it melts. Researchers fear that the melting of the glacier could lead to a global rise in sea level of up to 65 centimetres. As it is likely that the melting has already begun and is irreversible, the International Thwaites Glacier Collaboration (ITGC) has been formed to create an accurate picture of the glacier over the next five years. However, initial data paints an even gloomier picture than previously assumed.
The researchers, who were able to reach the edge of the glacier for the first time in February, collected data from the underside of the ice shelf with the help of a remote-controlled underwater robot. This area had previously been inaccessible to the researchers due to too much pack ice in front of the glacier front. They made a frightening observation: the glacier tongue is literally being hollowed out underwater from three sides by warmer water masses. “Thwaites has three weapons pointed at him. The warm water is coming from all directions,” explains Erin Pettit, glaciologist at Oregon State University and co-director of the ITGC. These warm currents reduce the stability of the glacier, which is the size of Great Britain or Austria and contains enough ice to cause global sea levels to rise by up to 65 centimeters as it melts. In addition, the melting of the glacier tongue could set off a chain reaction, as it prevents some glaciers from draining into the sea.
Last February, the conditions were ideal for Pettit and her colleagues to approach the edge of the glacier. With the help of a robot, the scientists were able to collect data under the ice shelf and map the sea floor. This revealed that warm water from the nearby Pine Island Glacier is being carried over and mixing with other warm water masses under the Thwaites Glacier. As a result, the previously stable eastern side of the glacier, which rests on a rock tongue, is melting faster than previously expected. If this side collapses, it will have a negative impact on the whole situation, says Pettit. This side only moves 600 meters per year, while the western side moves up to 2 kilometers per year. Next year, the robot is to go even further under the ice and penetrate to the grounding line, where the glacier lies on the land. In three years’ time, sufficient data should be available to provide more information about the future of the Thwaites Glacier.
Source: Jeff Tollefsen, Nature
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(C) Images and content are from: Landsat Composites of Coastal Changes, Amundsen Sea Embayment, West Antarctica
Christopher A. Shuman, UMBC-JCET, Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center
