New Study Provides 'Clearest Evidence Yet' of Polar Ice Melt

Nearly all of the world's polar ice sheets are melting at an increased rate .

This undated handout photo provided by NOAA shows Arctic ice. Federal officials say the Arctic region has changed dramatically in the past five years for the worse. It's melting at a near record pace, and it's darkening and absorbing too much of the sun's heat.
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All of Earth's major polar ice sheets except one have been rapidly losing mass — several gigatonnes per year — since 1992, accounting for about 20 percent of global sea level rise, according to a new report by multiple experts.

Scientists say this is the "clearest evidence yet" of polar ice losses, with nearly two thirds of all ice loss coming from Greenland. The only region with an increasing ice mass is Eastern Antarctica; ice sheets in west Antarctica, Greenland, and the Antarctic peninsula are melting and have caused about a half inch global sea level rise since 1992.

The study was spearheaded by Andrew Shepherd, a scientist at the University of Leeds and an author of the Intergovernmental Panel on Climate Change. The study included research from dozens of scientists from around the world, including NASA scientists.

Between 1992 and 2011, Greenland lost 152 gigatonnes of ice, West Antarctica lost 65 gigatonnes, and the Antarctic Peninsula lost 20 gigatonnes. East Antarctica gained about 14 gigatonnes of ice. A gigatonne is 1 billion metric tons.

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"Our new estimates are reliable and they are the clearest evidence of polar ice sheet losses," Shepherd said on a conference call Wednesday. Using combined data from more than 47 scientists, Shepherd says his team has finally been able to measure the amount of ice melting annually. "Crucially, this improved [technique] certainly allows us to say that both [Antarctica and Greenland] have been losing ice," he added.

The study suggests that ice loss in Greenland has rapidly increased over the past decade — earlier this year, about 97 percent of its ice cover melted during a heat wave.

"Greenland is losing mass at about 5 times the rate today as it was in the early 1990s," Erik Ivins of NASA's Jet Propulsion Laboratory said.

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Jason Koebler is a science and technology reporter for U.S. News & World Report. You can follow him on Twitter or reach him at jkoebler@usnews.com.