evidence: And the Arctic has other frozen land areas—mountain glaciers and ice caps—in places like Iceland, the Canadian and Russian Arctic, Alaska and Norway’s Svalbard Islands. These hold nowhere near as much water as the Greenland Ice Sheet but are still a significant part of the sea level equation. Together with glaciers and ice caps in the Southern Hemisphere (excluding the Antarctic Ice Sheet),their complete meltdown could potentially raise oceans nearly half a meter, according to the U.S. Geological Survey. But the northern areas have many more icy features than southern ones, Rignot notes. "Melting glaciers and ice caps in Patagonia and the other southern places don’t contribute as much as those in the Arctic," he says.