In a finding that may help scientists better predict sea-level rise in a warming world, Brown University researchers have found an underappreciated factor that controls the rate at which Greenland’s ice sheet melts.
In a finding that may help scientists better predict sea-level rise in a warming world, Brown University researchers have found an underappreciated factor that controls the rate at which Greenland’s ice sheet melts.
The research, published in the journal Science Advances, used satellite imagery to track the movement of the ice sheet’s snowline — the elevation above which the surface is snow-covered, and below which bare ice is exposed. The study showed that snowline elevation varied significantly from year to year, and that its variation exerted an outsized influence on the amount of solar radiation the ice sheet absorbed. Changes in snowline elevation from year to year explained more than half of the annual radiation variability on the ice sheet, the study found.
Ultimately, the amount of radiation the ice sheet absorbs determines the extent to which it melts.
“People who study alpine glaciers have recognized the importance of snowlines for years, but no one had explicitly studied them in Greenland before,” said Laurence C. Smith, a visiting fellow at the Institute at Brown for Environment and Society (IBES) and a study co-author. “This study shows for the first time that this simple partitioning between bare ice and snow matters more when it comes to melting than a whole host of other processes that receive more attention.”
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Image: The position of the snowline on Greenland's ice sheet has been found to play a key role in setting the pace at which the sheet melts. The image shows bright-hued snow above the snowline and darker bare ice below. Bare ice absorbs more solar radiation than snow, and therefore melts much more quickly. (Credit: NASA)
