The Greenland Ice Sheet is the world’s second-largest reservoir of fresh water sitting on the world’s largest island. It is almost mind-bogglingly huge.
If Greenland were suddenly transported to the central United States, it would be a very bad day for about 65 million people, who would be crushed instantly. But for the sake of science journalism, imagine that Greenland’s southernmost tip displaced Brownsville, Texas—the state’s southernmost city—so that its icy glaciers kissed mainland Mexico and the Gulf thereof. Even then, Greenland would stretch all the way north, clear across the United States, its northern tenth crossing the Canadian border into Ontario and Manitoba. Kansas City, Oklahoma City, and Iowa City would all be goners. So too would San Antonio, Memphis, and Minneapolis. Its easternmost peaks would slam St. Louis and play in Peoria; its northwestern glaciers would rout Rapid City, South Dakota, and meander into Montana. At its center point, near Des Moines, roughly two miles of ice would rise from the surface.
Suffice it to say: The Greenland Ice Sheet, which contains enough water to refill the Great Lakes 115 times over, is very large. And it is also falling apart.
A new study finds that the Greenland Ice Sheet added a quarter inch of water to global sea levels in just the past eight years. The research, published Monday in the journal Proceedings of the National Academy of Sciences, covers nearly 20 years previously not included in our detailed understanding of the troubled Greenland Ice Sheet. It finds that climate change has already bled trillions of tons of ice from the island reservoir, with more loss than expected coming from its unstable northern half.