Sea ice surrounding Antarctica reached a new record high extent this year, covering more of the southern oceans than it has since scientists began a long-term satellite record to map sea ice extent in the late 1970s. The upward trend in the Antarctic, however, is only about a third of the magnitude of the rapid loss of sea ice in the Arctic Ocean. Claire Parkinson, a senior scientist at NASA's Goddard Space Flight Center, has referred to changes in sea ice coverage as a microcosm of global climate change. Just as the temperatures in some regions of the planet are colder than average, even in our warming world, Antarctic sea ice has been increasing and bucking the overall trend of ice loss. Since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometers) of ice a year; the Antarctic has gained an average of 7,300 square miles (18,900 sq km). A warming climate changes weather patterns, said Walt Meier, a research scientist. Part of it is just the geography and geometry. With no northern barrier around the whole perimeter of the ice, the ice can easily expand if conditions are favorable," he said. Researchers are investigating a number of other possible explanations as well. Melting ice on the edges of the Antarctic continent could be leading to more fresh, just-above-freezing water, which makes refreezing into sea ice easier. Or changes in water circulation patterns, bringing colder waters up to the surface around the landmass, could help grow more ice.