Runoff from Greenland’s melting snow is one of the biggest potential contributors to sea level rise. Scientists usually gauge meltwater runoff by using regional climate models to compare calculations of melting at the surface with estimates of how much water refreezes — whatever water that doesn’t refreeze is considered runoff.
But recent research shows that supraglacial rivers flowing over the ice sheet could swell oceans even more than massive icebergs or the drainage from Greenland’s glacial lakes. To get these findings, a NASA-funded team led by Laurence Smith, chair of the geography department at UCLA, spent six days on the ice during July 2012 — directly after a record-setting ice sheet melt. They braved dangerous, slippery conditions to gather data in some of the planet’s most hostile terrain.
In Smith's own words:
One morning, our helicopter pilot gingerly approached the shore by that day’s destination, Lake Napoli, maneuvering to find a solid spot to land safely. We chose this particular lake because it wasn’t far from one of the supraglacial river sites where we’d been working, and it was so massive — about a mile in diameter. Plus, it was only about 40 to 50 miles from our base camp in Kangerlussuaq, a settlement in the western part of Greenland.
As with every other day of the trip, the weather cooperated and we had blue skies, but we knew the terrain could be treacherous — parking a helicopter on slushy, melting ice is not trivial.