Glacier ice is usually thought of as brittle. You can drill a hole in an ice sheet, like into a rock, and glaciers crack and calve, leaving behind vertical ice cliffs.
But new University of Washington research shows that glaciers are also slightly compressible, or squishy. This compression over the huge expanse of an ice sheet — like Antarctica or Greenland — makes the overall ice sheet more dense and lowers the surface by tens of feet compared to what would otherwise be expected, according to results published Jan. 19 in the Journal of Glaciology.
“It’s like finding hidden ice,” said author Brad Lipovsky, a UW assistant professor of Earth and space sciences. “In a sense, we discovered a big piece of missing ice that wasn’t accounted for correctly.”
Compression of the ice lowers the surface by up to 37 feet (11.3 meters) on the Antarctic ice sheet and by up to 19 feet (5.8 meters) on the Greenland ice sheet. Averaged across the entire Antarctic ice sheet, the surface is lower by 2.3 feet (0.7 meters), which represents 30,200 gigatons of additional ice. For Greenland, the surface of the ice sheet is lowered by an average of 2.6 feet (0.8 meters), which represents 3,000 gigatons of ice.
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