The Earth's ozone layer is expected to recover within the next 40 years as ozone-depleting chemicals are being phased out of use, a panel of international experts backed by the U.N. says. The panel, which publishes a new ozone layer report every four years, credits the phasing out out of nearly 99% of ozone-depleting chemicals for the improvement.

The agency said the Montreal Protocol, a landmark global agreement to phase out harmful chemicals, has significantly aided the recovery of the ozone layer. The Montreal Protocol entered into force in 1989 and regulates nearly 100 manmade chemicals that damage the ozone layer.

"The impact the Montreal Protocol has had on climate change mitigation cannot be overstressed," said Meg Seki, the executive secretary of the U.N. Environment Programme's Ozone Secretariat. "Over the last 35 years, the Protocol has become a true champion for the environment."

The U.N. also noted that a 2016 amendment to the measure, the Kigali Amendment to the Montreal Protocol, is helping to significantly reduce climate change. The amendment requires global powers to reduce the production and consumption of many hydrofluorocarbons, or HFCs. While these types of chemicals don't directly affect the ozone layer, they're considered potent greenhouse gases.

"Ozone action sets a precedent for climate action. 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 gases and so limit temperature increase," said World Meteorological Organization Secretary-General Prof. Petteri Taalas.

Research from the U.S. National Oceanic and Atmospheric Administration that was published in 2022 found that global concentrations of ozone-depleting chemicals had declined just over 50% in the mid-latitude stratosphere, to levels observed in 1980. NOAA scientists said that the continued decline "shows the threat to the ozone layer receding below a significant milestone in 2022."

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