Until recently, researchers believed that Greenland was losing 550 trillion pounds of ice a year. New research published Sept. 21 in Science Advances shows they might have vastly underestimated how bad the situation is.
Typically, scientists estimate ice loss based on satellite images of changes in the Earth’s surface, combined with calculations used to compensate for “glacial isostatic adjustment,” a phenomenon where the earth’s crust rises up after large amounts of ice melt away.
But in the new study, a team of scientists used a network of GPS sensors to figure out how quickly the earth was bouncing back up, and concluded that the previous compensation method was inaccurate. In fact, they say, previous methods were underestimating ice loss by 20 million tons a year—or about 40 trillion pounds. So in actuality, Greenland lost an average of 590 trillion pounds of ice every year between 2003 and 2013.
Though that may not seem like a huge difference, it’s significant enough to impact global sea rise, and accurately calculating ice loss is key in predicting future effects of climate change. Watch the video above to see the ice loss in action.