Helicopter Flight over the Greenland Ice Sheet (VIDEO)
Caption
Paul Bierman, a geologist at the University of Vermont and his colleagues --f rom UVM, Boston College, Lawrence Livermore Laboratory, and Imperial College London--wanted to develop a better understanding of the ancient history of the huge ice sheet that covers Greenland, like this portion of the ice sheet shown from a helicopter on a Bierman-led expedition there. The team studied deep cores of ocean-bottom mud containing bits of bedrock that eroded off of the east side of Greenland. Their results show that East Greenland has been actively scoured by glacial ice for much of the last 7.5 million years--and indicate that the ice sheet on the eastern flank of the island has not completely melted for long, if at all, in the past several million years. Their field-based data also suggest that during major climate cool-downs in the past several million years, the ice sheet expanded into previously ice-free areas, "showing that the ice sheet in East Greenland responds to and tracks global climate change," Bierman says. "The melting we are seeing today may be out of the bounds of how the Greenland ice sheet has behaved for many millions of years."
Credit
Joshua Brown/UVM
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