Greenland's ice sheet is worrying scientists. It's melting.
Since the 1990s, Greenland's been losing 100 billion tons of ice per year. This may seem like a distant problem, but if Greenland's ice melts entirely, sea level will rise about twenty-three feet.
That's enough to flood all the world's coastal cities, including New York and Miami. And if too much ice enters the ocean at one time, the world's ocean currents could be altered, dramatically changing climates in some areas.
Massive Ice Sheet
Scientists estimate that Greenland's been buried in ice for much of the last 110,000 years. The massive ice sheet, second in size only to Antarctica's, covers 660,000 square miles.
It's 1,500 miles long, over a mile thick, and blankets eighty percent of Greenland's surface. With such an enormous amount of ice to deal with, it's not surprising that scientists are racing to understand how and why the ice is melting.
Why Is The Ice Sheet Melting?
Some of Greenland's ice loss is due to glaciers flowing into the sea. The speed of their flow depends on the interface between the ice and the rocky surface below. The more friction, the slower the movement.
Melting surface water can reduce that friction. It trickles through cracks until it reaches the ice rock interface where it acts as a lubricant, allowing the ice to slide.
Scientists assumed that slow and steady increases in worldwide temperatures would create greater glacier movement, but more recent research suggests that short term warm weather spikes might be more harmful.
Slow melting creates channels for the water to escape so the entire ice rock interface is not lubricated, while large, short term water-melts can flood the interface, causing glaciers to move farther and faster.
In either case, Greenland's ice is melting. Coastal cities need to have a plan.