In fact, in late September, satellite data indicated that Antarctica was surrounded by the greatest area of sea ice ever recorded in the region: 7.51 million square miles (19.44 million square kilometers), the U.S. National Snow and Ice Data Center announced Thursday. Even so, it's a slow rate of growth—about one percent over last year—not nearly enough to offset melting in the Arctic, which broke records just weeks ago.

National Geographic asked Eric Rignot, a NASA researcher and earth systems professor at UC Irvine, whether the data is good news, and what it means for the rise of global sea levels, which are fueled by melting ice.

If the world was warming up uniformly, you would expect the sea