A three decades old international treaty to phase out chemicals that deplete the ozone layer protecting our planet from harmful solar radiation is paying off. According to the 2018 Scientific Assessment of Ozone Depletion released by the World Meteorological Organization and the United Nations Environment Programme, the ozone layer is recovering.
This includes the “hole” over Antarctica where the ozone layer is exceptionally thin, which has been gradually shrinking since the early 2000s and is projected to heal by the 2060s. This year, the hole spanned about 9 million square miles, an area slightly smaller than the entire North American continent.
“Generally, it’s good news,” says Paul Newman, co-chair of the new assessment and chief scientist of earth sciences at NASA Goddard Space Flight Center. Ozone-depleting gases are decreasing and have continued to fall since the mid-1990s. “The projections into the future are pretty positive as long as parties continue to comply with the Montreal Protocol.”
That’s not to say there aren’t any flies in the ointment, Newman says. Certain ozone-depleting substances like chlorofluorocarbon-11 (CFC-11) are decreasing from the atmosphere more slowly than projected. Two independent networks have confirmed an uptick of emissions over eastern Asia since 2012, though their exact origins are still being investigated. That’s troubling because compounds including CFC-11 are banned under the Montreal Protocol and persist in the atmosphere for decades. If someone is releasing them today, they’ll continue to do damage for generations to come.