A massive hole the size of Lake Superior has opened in the ice that covers Antarctica’s Weddell Sea, a phenomenon that hasn’t been seen since the mid-1970s. This hole, called a polynya, opens up 80,000 square kilometers (31,000 square miles) of ocean in the middle of the Weddell Sea’s ice pack, hundreds of miles from shore. "This is hundreds of kilometers from the ice edge. If we didn’t have a satellite, we wouldn’t know it was there," explains professor Kent Moore, an atmospheric physicist at the University of Toronto.
Large-scale glacial melt is one of the realities that is being addressed by researchers in regards to global warming, as these systems of ice are the chief source of water contributing to sea level rise as global temperatures increase. There is a great deal of concern over the ice sheets covering Greenland, melting due to the nature of ocean currents in the region, and the ice shelves in West Antarctica, vulnerable from melt caused by warm water from below, as well as increasingly warm air from above. In contrast, the much more massive ice sheet that covers East Antarctica has historically been considered stable, and has been recorded as gaining ice in recent years, as opposed to the losses seen by Greenland and West Antarctica.