The Greenland Ice Sheet has melted to a point of no return. In a paper published in Nature, researchers at Ohio State University found that even if global warming were to stop today, the sheet would still disintegrate. Greenland’s ice sheet releases more than 280 billion metric tons of melting ice into the ocean each year, making it the single greatest contributor to global sea level rise.
The paper, ‘Dynamic ice loss from the Greenland Ice Sheet driven by sustained glacier retreat’, found that Greenland’s glaciers are rapidly shrinking and at this point, the snowfall that replenishes the ice sheet each year is not enough to counterbalance the ice that is flowing into the ocean. Relying on more than three decades of observational data, the study found that the ice sheet is losing mass at accelerated rates. Specifically after 2000, the ice sheet began losing mass permanently. In fact, the amount of ice that has disappeared is so huge that it has caused a noticeable change in the gravitational field over the island.
Michalea King, lead author of the study and a researcher at Ohio State University’s Byrd Polar and Climate Research Center, said, ‘We’ve been looking at these remote sensing observations to study how ice discharge and accumulation have varied. And what we’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet.’
By analysing satellite data from more than 200 large glaciers draining into the ocean around Greenland, researchers could assess how much ice breaks off into icebergs or melts from the glaciers into the ocean, the amount of snowfall each year, and how these glaciers get replenished. The amount of ice being lost each year started increasing steadily around 2000 – estimated to be about 500 gigatons each year. At the same time, snowfall did not increase but the rate of ice loss stayed about the same over the last decade. This means that the ice sheet has been losing ice more rapidly than it’s being replenished. It is now at the point of no return – to reiterate, even if global warming were to completely stop, the sheet will still keep shrinking.
The melting ice in Greenland already contributes more than a millimetre rise to sea level every year and this will only increase with a gradually warming planet. Sea levels are projected to rise by more than 3 feet by the end of the century which will mean that many coastal cities and low-lying island nations are likely to go underwater. It should be noted that Greenland is the largest ice sheet on the planet after Antarctica.