The Greenland ice sheet—a behemoth body of ice composed of layers of 100,000-year-old compacted snow—is particularly vulnerable to climate change.

If it were to completely melt, sea levels around the globe would rise by a staggering 25 feet. Recent analysis of NASA satellite, laser and radar data, which spanned nearly a decade, not only indicates that the ice sheet suffered an average loss of about 80 trillion gallons of ice per year between 2003 and 2012, but the resulting changes in ice thickness from region to region also varied each year. These findings suggest that the ice sheet is more complex and thinning more rapidly than previously thought. The implications are vast. Even slight increases in sea level could impact coastal habitats and force hundreds of millions of people to relocate due to the increased risk of flooding.