An international agreement to ban ozone-depleting chemicals is helping to rebuild the planet’s protective layer and shield humans from harmful solar rays, according to UN-backed scientists.
(Bloomberg) — The Earth’s protective layer is on track to recover within four decades as damaging airborne chemicals are phased out, helping to shield humans from the sun’s rays and limit global warming, a UN-backed scientific panel said. Scientists first identified a hole in the ozone layer, which helps filter out ultraviolet rays from the sun, in 1985.A rare international agreement was reached in 1987 to phase out gases including chlorofluorocarbons (CFCs), which were used in products such as air conditioners, refrigerators and deodorants but were breaking down ozone in the upper atmosphere. A 2016 update to the so-called Montreal Protocol also phased out hydrofluorocarbons (HFCs), which do not directly deplete ozone but have a strong climate change effect.Since the chemicals were banned, there has since been a “notable recovery” in the upper layer of the stratosphere, according to the report by the Scientific Assessment Panel to the Montreal Protocol, which is updated every four years. The HFC phase-out has also avoided an estimated 0.5C of warming by 2100.“Ozone action sets a precedent for climate action,” said Professor Petteri Taalas, Secretary-General of the World Meteorological Organization. “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.”If current policies remain in place, the ozone layer is expected to recover to 1980 levels — before the appearance of the hole — by around 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the world. The hole, which is over the Antarctic, has been shrinking in area and depth since the year 2000, the report said.
However, proposals to use geoengineering in the atmosphere to reduce global warming by reflecting more sunlight into space could have unintended consequences, including delaying ozone recovery, the report warns.
Other factors including rocket launches and more frequent intense wildfires exacerbated by climate change could also delay the recovery, and more research is needed to understand how much.
Often held up as a success story for international environmental negotiation, the Montreal Protocol has relevance for modern efforts to cut carbon emissions and mitigate climate change, the UN said.
“The impact the Montreal Protocol has had on climate change mitigation cannot be overstressed,” Meg Seki, executive secretary of the United Nations Environment Programme’s Ozone Secretariat in a press release.
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