September 17, 2012

Cornell Researchers Say Glaciers in Patagonia Are Melting Rapidly

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That the glaciers in Earth’s polar region are melting may seem like old news, but a recent study by Cornell researchers shows that climate change is rapidly melting the seldom-studied ice fields in Southern Patagonia, too.The region’s glaciers are melting at a rate that has almost doubled over the last 12 years, according to the study, which was conducted by research associate Michael Willis, Andrew Melkonian grad and Prof. Matthew Pritchard, earth and atmospheric sciences.The researchers found a large shift in the rate at which the Southern Patagonian Ice Field, located at the southern tip of South America between Argentina and Chile, was melting.“The rate of volume change for the ice field as a whole from 2000 to 2012 was about 50-percent faster than the rate found previously by other authors between 1975 and 2000,” Willis said.The ice field is the world’s second largest temperate field. Because the temperature of the ice field is near freezing point year-round, its glaciers are temperate relative to much colder polar glaciers, and the field is never completely frozen. As a consequence, “climate change signals at the Patagonian ice field are fairly subtle” compared to their polar counterparts, according to Willis.Even so, the effects of climate change on the ice fields seem to have become more dramatic in recent years, researchers said.Some of Southern Patagonia’s glaciers are losing up to 20 to 30 meters of thickness per year, Pritchard said. Over the last 10 years, he said, a glacier labelled HPS 12 lost 450 meters, or 1,350 feet, of ice — about the height of the Empire State Building.Because the ice fields are mostly unpopulated, it is unclear what the direct impact the melting will have on humans. However, the melting of the glaciers has a significant impact on the amount of water they feed into nearby reservoirs, which in turn greatly influences communities in the region, Willis said.Willis said that researchers suspect the melting may be contributing to the increasing occurrences of “glacial lake outburst floods,” which take place when lakes fed by glaciers suddenly release all their water over an extremely short time period.Although the floods are difficult to predict and monitor, Cornell’s study “may help focus some attention on the problem,” Willis said.The external impact of the melting of the ice field is difficult to assess without field experiments, according to Willis. Still, he said, Cornell researchers gathered thousands of data points using remote sensing and satellite imaging — technologies that allow researchers to collect information about objects without coming into physical contact with them.By using a new technique that involves “stacking” more than 100 high-resolution maps of the ice field on top of each other, the team created and analyzed how the glaciers’ elevation changed over time, according to Willis.Stacking the maps was akin to creating “a thick stack of pancakes, with the oldest map on the bottom and the newest map on the top … [and] the edges of the pancake being perfectly aligned,” Willis said.The team used the time series — a collection of elevation points measured over regular time intervals — to figure out the rate at which the surface of the glaciers was changing at each point.The team hopes that, in the future, it will receive additional funding to study more temperate ice fields and conduct field experiments.“We’re interested in doing research in Alaskan ice fields, which are similar to the Patagonian fields in latitude, geography and temperature,” Pritchard said.

Original Author: Olivia Dang