Measuring the Loss of the Greenland Ice Sheet

At a dinner party a few years ago, I happened to be seated next to a senior scientist at the Jet Propulsion Laboratory (JPL, in Pasadena, CA) who led a team of scientists that measures the declining thickness of the Greenland Ice Sheet.  He pointed out that measuring the surface area is a piece of cake, but figuring out what’s happening beneath it is quite a challenge.

As one can imagine, a significant amount of the ice melts from the bottom up, forming huge rivers that flow into the North Atlantic. The tool he and his team designed is the subject of this article.  Instead of monitoring the volume of the ice melt, it measures changes in the Earth’s gravitation field to infer the content of what’s creating that field.