Arctic river ice deposits rapidly disappearing

College of Arts & Sciences

UNC-Chapel Hill hydrologist Tamlin Pavelsky is the lead author of a new study published in Geophysical Research Letters, a journal of the American Geophysical Union, which shows arctic river icings are declining rapidly. 
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Climate change is causing thick ice deposits that form along Arctic rivers to melt nearly a month earlier than they did 15 years ago, a new study finds.
River icings form when Arctic groundwater reaches the surface and solidifies on top of frozen rivers. They grow throughout the winter until river valleys are choked with ice. Some river icings have grown to more than 10 square kilometers (4 square miles) in area – roughly three times the size of New York’s Central Park – and can be more than 10 meters (33 feet) thick.
In the past, river icings have melted out around mid-July, on average. But a new study measuring the extent of river icings in the U.S. and Canadian Arctic shows most river icings disappeared 26 days earlier, on average, in 2015 than they did in 2000, melting around mid-June. In addition, the study found most icings that don’t completely melt every summer were significantly smaller in 2015 than they were in 2000. Watch a video of river icings here.
A river icing on a small unnamed river that drains into Galbraith Lake, Alaska. (Photo by Jay Zarnetske)“This is the first clear evidence that this important component of Arctic river systems – which we didn’t know was changing – is changing and it’s changing rapidly,” said Tamlin Pavelsky, a hydrologist and associate professor of geological sciences in the College of Arts and Sciences at the University of North Carolina at Chapel Hill, an affiliate faculty member of the UNC Institute for the Environment, and lead author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union.
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