The seasonal ozone hole above the Antarctic was the second smallest in 20 years as warm temperatures slowed depletion of the layer that shields the planet from ultraviolet radiation, according to the National Oceanic and Atmospheric Administration.
The average size of the ozone hole this year was 6.9 million square miles (17.9 million square kilometers) and reached a maximum of 8.2 million square miles on Sept. 22, the agency said in a statement today.
The Antarctic ozone hole first appeared in the 1980s and was one of the first signs of man-made climate change, according to the statement. International efforts to regulate chlorofluorocarbons, the chemicals blamed for the annual event, may not lead to any measurable recovery in the layer for a decade.
“It happened to be a bit warmer this year high in the atmosphere above Antarctica, and that meant we didn’t see quite as much ozone depletion as we saw last year,” Jim Butler, the director of global monitoring at NOAA’s Earth System Research Laboratory in Boulder, Colorado, said in the statement.
Last year’s gap stretched 10.1 million square miles and was the ninth largest. The biggest was in 2000 at 11.5 million square miles.