As the largest single chunk of melting snow and ice in the world, the massive ice sheet that covers about 80 percent of Greenland is recognized as the biggest potential contributor to rising sea levels due to glacial meltwater.
Until now, however, scientists’ attention has mostly focused on the ice sheet’s aquamarine lakes — bodies of meltwater that tend to abruptly drain — and on monster chunks of ice that slide into the ocean to become icebergs.
But a new UCLA-led study reveals a vast network of little-understood rivers and streams flowing on top of the ice sheet that could be responsible for at least as much, if not more, sea-level rise as the other two sources combined.
When snow and ice thaw during the summer, these waterways form an intricate drainage system that captures virtually all surface runoff and is capable of flushing its entire volume in less than two days, the team found.
“It’s the world’s biggest water park, with magnificent and beautiful — but deadly — rushing blue rivers cutting canyons into the ice,” said Laurence C. Smith, the study’s lead author and the chair of UCLA’s geography department.
Image shows researchers on the ice sheet. The moved around the ice sheet by helicopter because the ice sheet was so unsteady and the amount of territory they covered was so great. Credit UCLA.
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