Greenland

Greenland’s ice sheet is the second largest ice body in the world, after the Antarctic ice sheet. It’s easy to think of Greenland as a solid, impenetrable block of ice—but 80% of the ice sheet’s surface has more or less the consistency of a slushie. Melt from Greenland already accounts for 25% of global sea-level rise. Even by conservative estimates, Greenland could contribute another quarter-meter of sea-level rise by 2100—within the lifetime of children living today. Scientists have defined the disintegration of the Greenland Ice Sheet as one of five potential climate tipping points. All in all, the ice sheet holds enough water to raise oceans by 7 meters—and no one knows whether, or how fast, that water will be unleashed.