Ice stream draining Greenland Ice Sheet sensitive to changes over past 45,000 years

phys.org | 5/14/2018 | Staff
SweetStuff33 (Posted by) Level 3
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A ribbon of ice more than 600 kilometers long that drains about 12 percent of the gigantic Greenland Ice Sheet has been smaller than it is today about half of the time over the past 45,000 years, a new study suggests.

Interestingly, the loss of ice from the Northeast Greenland Ice Stream (NEGIS) took place not only during the warm Holocene period, but also during a period thought to be very cold preceding the last glacial maximum, the researchers say.

Findings - NEGIS - Changes - Influence - Climate

The findings suggest that NEGIS is particularly sensitive to environmental changes, which may exacerbate the influence of anthropogenic climate change. Results of the study are being published today in Nature Communications.

"There are some parts of the ice sheet that are relatively stable and others that show evidence of very rapid retreating—a pattern we're seeing today as well as thousands of years ago," said Anders Carlson, an Oregon State University geologist and co-author on the study. "Some of it relates to bed topography—when the bed is below sea level, it stabilizes that part of the ice sheet. In low spots, it is unstable."

Carlson - Factors - Ice - Mass - Loss

Carlson said different factors may help explain the ice mass loss, including orbital forcing and warm summer temperatures. The path of the Earth's orbit put it closer to the sun some 9,000 years ago, breaking the planet out of its glacial maximum. NEGIS showed significant ice loss.

Yet it also showed a loss of ice during the period preceding that maximum, about 41,000 to 26,000 years ago, which is thought to have been...
(Excerpt) Read more at: phys.org
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