NASA is keeping a watchful eye on Greenland, tracking changes in the thick sheet of ice that covers most of the island. Why? Well for the same reason that coal miners used to bring canaries into the coal mines. If they stopped singing, it was a warning sign that trouble was coming. Greenland's ice sheet is one of Earth's canaries when it comes to global warming. Polar regions are more sensitive to a warming Earth than other parts of the world. So what happens in places like Greenland, the rest of the Arctic, and Antarctica, alerts us to what’s in store for the rest of the planet. And Greenland’s ice can also affect many of us directly. You see, Greenland has more land ice than any other place except Antarctica. If it all melted, it would raise sea level around twenty-three feet.
That’s enough to put coastlines throughout the world under water. And in fact, the ice is melting. It’s far from all gone — that could take centuries. But Greenland’s ice sheet currently adds about 250 gigatonnes of water to the ocean every year. What’s a gigatonne? It’s a billion tonnes, which is approximately a block of ice one kilometer square. And 250 of these giant Greenland ice blocks melt every year. All this extra fresh water from this melting ice could also change circulation patterns in the ocean… and in the atmosphere. Which means even if you don’t live near the ocean, a melting Greenland could potentially affect your local weather in the future. So that’s why NASA is monitoring Greenland's ice sheet. It's like that canary in the coal mine warning us of trouble. By tracking and measuring the changes we'll all be better prepared for the future.