The massive Greenland Ice Sheet, the second largest ice sheet in the world, has long been considered a threat to global sea level rise, and now new research finds that its network of meltwater rivers and streams may be a major contributor to these rising waters.
In the past, scientists have focused their attention mostly on the ice sheet’s lakes – bodies of water that quickly drain – and the massive slabs of ice that break off from Greenland and slide into the ocean, later to become icebergs.
Until now, little attention has been paid to the rivers and streams flowing on top of the ice sheet. But researchers show that this ill-considered factor plays a bigger role than previously realized, most likely responsible for the same, if not more, sea level rise than the other two sources combined.
When snow and ice thaw during the summertime, these waterways form a complex drainage system that captures virtually all surface runoff from the ice sheet, and can release this water in a matter of just two days.