from the EUV-from-above dept.
NASA and the US National Oceanic and Atmospheric Administration have been monitoring the ozone hole since it was first discovered in 1985. The agencies use satellites, weather balloons and ground-based instruments to study and track the hole. The ozone hole changes throughout the year and reached its 2017 peak size on Sept. 11 at the end of the region's wintertime.
Scientists weren't surprised by the size of the hole this year. "This is what we would expect to see given the weather conditions in the Antarctic stratosphere," says Paul A. Newman, a scientist at NASA's Goddard Space Flight Center. NASA cites warmer global temperatures as a factor in reducing the hole.
But don't get too excited. NASA says the smaller hole "is due to natural variability and not a signal of rapid healing." The ozone hole still covered 7.6 million square miles (nearly 20 million square kilometers), or over two and a half times the size of Australia. Still, scientists are optimistic about the ozone hole eventually healing over time.