Sea Ice Around Antarctica Reaches a Record Low
Sea ice around Antarctica has reached a record low in four decades of observations, a new analysis of satellite images shows. From a report: As of Tuesday, ice covered 750,000 square miles around the Antarctic coast, below the previous record low of 815,000 square miles in early March 2017, according to the analysis by the National Snow and Ice Data Center in Boulder, Colo. "It's really unprecedented," said Marilyn N. Raphael, a professor of geography at the University of California, Los Angeles, who studies Antarctic sea ice. Warmer ocean temperatures may have played a role, she said, "but there are other factors that we will be working on finding out in the next months." Antarctic sea ice extent is highly variable from year to year, but overall has increased very slightly, on average, since the late 1970s, when satellite observations began. By contrast, sea ice extent in the Arctic, which is warming about three times as fast as other regions, has decreased by more than 10 percent a decade over the same period. The two regions are very different. The Arctic Ocean covers high latitudes, including the North Pole itself, and is hemmed in by land masses. In the Southern Hemisphere, Antarctica covers the pole. The Southern Ocean, which surrounds the continent, begins at much lower latitudes and is open to the north. While rapid warming in the Arctic is largely responsible for the shrinking of sea ice there, the effect of climate change on Antarctic sea ice is far less clear. Edward Blanchard-Wrigglesworth, a climate scientist at the University of Washington, said that many scientists expect that global warming will eventually lead to declines in Antarctic sea ice. But right now, he said, "it's really hard to connect the two, especially in terms of single events like this one." Instead, a complex group of factors is at play when it come to Antarctic sea ice. Large-scale atmospheric patterns, often occurring far from the continent, as well as local ocean currents and winds can all increase or reduce sea-ice coverage.
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