The long-lamented hole in the ozone layer is slowly mending itself, thanks to the success of an international agreement that banned chemicals that eat away at it, according to a new report from the United Nations (U.N.).
If current policies are maintained, the ozone above the Antarctic will return to 1980 levels by 2066, and the Arctic will reach that threshold by 2045. The area between is expected to recover by 2040, per the report.
Earth’s ozone layer, located between about 9 and 22 miles above the planet’s surface, absorbs ultraviolet and other radiation, protecting life on Earth from the sun’s harmful rays.
Scientists from the British Antarctic Survey first announced their discovery of a thinned area of ozone—or a “hole”—back in May 1985. Spurred by this shocking revelation, the world sprang to action. Just two years later, 197 countries adopted an agreement called the Montreal Protocol to stop the use of 100 ozone-depleting chemicals. These included chlorofluorocarbons, or CFCs, which were once commonly found in spray cans, refrigerants and foam insulation.
The new report found that 99 percent of these banned substances have successfully been phased out worldwide.
“The recovery of the ozone layer is on track,” David W. Fahey, director of the National Oceanic and Atmospheric Administration’s Chemical Sciences Laboratory and lead author of the new assessment, tells the New York Times’ Henry Fountain. “The peak destruction of the global ozone layer is behind us due to the effectiveness of the control measures of the Montreal Protocol that have been adopted by all nations.”
While ozone thinning is not a major contributor to climate change, the Montreal Protocol has helped avoid about 0.5 degrees Celsius of global warming, per the U.N. report. In 2016, countries added an amendment to phase down the consumption and production of hydrofluorocarbons, which are potent greenhouse gases. This addendum, called the Kigali Amendment, will avoid up to another 0.5 degrees Celsius in global warming by 2100, per the U.N. report.
Experts point to the success of the Montreal Protocol as hope for the world’s future dealing with climate change.
“Ozone action sets a precedent for climate action,” Petteri Taalas, secretary-general of the World Meteorological Organization, says in a statement. “Our success in phasing out ozone-eating chemicals shows us what can and must be done as a matter of urgency to transition away from fossil fuels, reduce greenhouse gasses and so limit temperature increase.”
But achieving a similar phaseout of widely used greenhouse gases like carbon dioxide may be more difficult, Fahey tells the Guardian’s Oliver Milman. These gases are embedded in nearly every aspect of our society.
“Getting every person on the planet to stop burning fossil fuels is a vastly different challenge,” he tells the publication. “CO2 is another order of magnitude when it comes to its longevity, which is sobering.”
In a first, the report also examined how a proposed climate intervention called stratospheric aerosol injection might impact the ozone layer. The controversial geoengineering solution would release sulfur aerosols into the atmosphere to reflect some incoming solar radiation, cooling the planet.
Some scientists have argued this strategy could have unintended side effects on weather. In the report, the U.N. cautioned against taking this action. Their results are uncertain, but trying to cool the Earth by 0.5 degrees Celsius using aerosols would likely have some effect on the ozone, per the organization. Still, it “will not destroy the ozone layer and create catastrophic consequences,” Fahey tells the Times.