Govind Tekale
Earth’s protective ozone layer continues to heal, with the 2024 Antarctic ozone hole smaller than in recent years, according to the World Meteorological Organization’s (WMO) latest Ozone Bulletin.
Scientists measured this year’s maximum ozone mass deficit at 46.1 million tonnes on September 29, well below the 1990-2020 average. The hole’s onset was also slower than usual, with delayed depletion through September followed by a quicker recovery – a pattern experts call “a robust indication of initial recovery.”
“Today, the ozone layer is healing,” said UN Secretary-General António Guterres. “This achievement reminds us that when nations heed the warnings of science, progress is possible.”
The positive trend reflects successful global action through the Montreal Protocol, which has eliminated over 99% of controlled ozone-depleting substances since its adoption in 1987. These chemicals were once widely used in refrigeration, air conditioning, firefighting foam, and even hairspray.
While natural atmospheric factors partly caused this year’s lower depletion, the long-term recovery trend is clear. Scientists project the ozone layer will return to 1980 levels (before the hole appeared) around 2040 globally, by 2045 over the Arctic, and by 2066 over the Antarctic – assuming current policies stay in place.
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“Despite the great success of the Montreal Protocol, this work is not yet finished,” warned Matt Tully, Chair of WMO’s Scientific Advisory Group on Ozone. “There remains an essential need for the world to continue careful systematic monitoring of both stratospheric ozone and of ozone-depleting substances and their replacements.”
The Kigali Amendment to the Protocol, ratified by 164 countries so far, targets powerful greenhouse gases called hydrofluorocarbons (HFCs) that replaced earlier banned substances. While HFCs don’t deplete ozone, they contribute significantly to global warming. Their phase-down could avoid up to 0.5°C of warming by the century’s end.
Climate-related events like wildfires pose new challenges. A 2022 assessment found that smoke from Australia’s 2019-2020 wildfires destroyed about 1% of the ozone layer above the Southern Hemisphere – showing how extreme climate events could slow recovery.
The ozone layer’s healing delivers significant health benefits by reducing exposure to harmful ultraviolet radiation, which causes skin cancer, cataracts, and ecosystem damage. The recovery also supports multiple UN Sustainable Development Goals related to health, climate action, and protecting life on land.
WMO Secretary-General Celeste Saulo emphasized how international cooperation made this progress possible: “WMO’s scientific research into the ozone layer dates back decades. It is underpinned by trust, international collaboration and commitment to free data exchange – all cornerstones of the world’s most successful environmental agreement.”
As World Ozone Day marked the 40th anniversary of the Vienna Convention that first recognized this global problem, experts caution that continued monitoring and policy compliance remain essential to secure the healing already underway.
