Greenland's ice sheet has melted past the point of no return, according to climatologists at Ohio State University's Byrd Polar and Climate Research Center: “Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss. Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.”
According to the report, “Nearly 40 years of satellite data from Greenland shows that glaciers on the island have shrunk so much that even if global warming were to stop today, the ice sheet would continue shrinking. … The researchers found that, throughout the 1980s and 90s, snow gained through accumulation and ice melted or calved from glaciers were mostly in balance, keeping the ice sheet intact. Through those decades, the researchers found, the ice sheets generally lost about 450 gigatons (about 450 billion tons) of ice each year from flowing outlet glaciers, which was replaced with snowfall. … The researchers' analysis found that the baseline of that pulse—the amount of ice being lost each year—started increasing steadily around 2000, so that the glaciers were losing about 500 gigatons each year. Snowfall did not increase at the same time, and over the last decade, the rate of ice loss from glaciers has stayed about the same—meaning the ice sheet has been losing ice more rapidly than it's being replenished.”