On Greenland, tens of thousands of years of snowfall have settled and solidified into a massive sheet of ice. Each summer, snow retreats briefly at low elevations, and a narrow strip of rocky coastline emerges. While some seasonal thawing is typical on Greenland, more dramatic changes are probably in store for the Greenland Ice Sheet in coming decades and centuries.
In October 2006, a study using data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites discussed the condition of the Greenland Ice Sheet. The study determined that, although the ice sheet had gained some mass in the interior, it had lost considerably more mass along the perimeter, particularly southeastern Greenland.
Where once two streams of ice merged in Greenland’s Jakobshavn Glacier, today there is division and a complex surface riddled with crevasses and melt ponds.
The amount of ice flowing from the Antarctic glacier has doubled in the span of three decades, and scientists think it could undergo even more dramatic changes in the near future.
A peek under the ice reveals a Grand Canyon-sized channel under the Jakobshavn glacier—one reason why the Greenland glacier contributes more to sea level rise than any other single feature in the Northern Hemisphere.