Smaller ozone hole in 2024 pushes Earth closer to seeing it vanish
A new World Meteorological Organization (WMO) report offers good news about Earth's ozone layer, which is on the road to a recovery to 1980 values in the coming decades--a positive sign for the health of people and the planet.
If there is one piece of good news regarding our planet's future, it's our ozone layer and the ongoing shrinking of its once-massive hole.
In an update on the latest status of the hole in Earth's ozone layer, the World Meteorological Organization (WMO) said the planet's protective ozone layer is healing and the hole in 2024 was smaller than in recent years. The information was released in a bulletin on Sept. 16.
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WMO's ozone report stated that the low level of ozone depletion documented last year was partially a result of naturally occurring atmospheric factors, which push year-to-year fluctuations. But the long-term, positive trend shows the success of focused, international action over the years.
“Forty years ago, nations came together to take the first step in protecting the ozone layer — guided by science, united in action,” said António Guterres, United Nations Secretary-General, in a news release published earlier this month.
False-colour view of the total ozone over the Antarctic pole on July 27, 2024. The purple and blue colours are where there is the least ozone, and the yellows and reds are where there is more ozone. (NASA Ozone Watch)
“The Vienna Convention and its Montreal Protocol became a landmark of multilateral success. Today, the ozone layer is healing. This achievement reminds us that when nations heed the warnings of science, progress is possible."
More stratospheric ozone cover in 2024 than in recent years
The ozone layer shields the planet from the sun's ultraviolet radiation, which can cause skin cancer and other health risks from exposure over time.
The organization noted the complete stratospheric ozone cover in 2024 was higher over most of the planet when comparing it to past years.
The Antarctic ozone hole, which hovers over the continent every spring, was smaller than the 1990 to 2020 average, registering a maximum ozone mass deficit (OMD) of 46.1 million tonnes on Sept.29. WMO said it was smaller than the relatively large holes seen between 2020 and 2023.
Aerosols explainer. (European Space Agency (ESA)
However, the process was comparatively sluggish and there was a delayed ozone depletion documented in September, followed by a partial, quick recuperation after the peak deficit was obtained.
“This persistent later onset has been identified as a robust indication of initial recovery of the Antarctic ozone hole,” the WMO bulletin said.
With the gradual improvement of the ozone layer, actions taken as a result of the Montreal Protocol can be attributed to the phasing out of more than 99 per cent of the production and consumption of controlled ozone-depleting substances,
WMO said. Such materials were formerly used in refrigeration, air conditioning, firefighting foam and even hairspray.
Ozone layer could be restored to pre-hole level
Because of the actions taken to cut out those substances, the ozone layer is on a path to a recovery to 1980s levels by the middle of this century, WMO said, leading to a major reduction in risks of skin cancer, cataracts, and ecosystem damage from excessive ultraviolet (UV) exposure.
That restoration is dependent on countries' regulations remaining intact, though.
Ozone layer extent over Antarctica from 2019 to 2024. (NASA Ozone Watch/The Weather Network)
If they do, the ozone layer is projected to see its status return to 1980 values, before the ozone hole was created, by around 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the globe, according to the most recent assessment conducted in 2022. The next analysis will be released in 2026.
In terms of monitoring the size of the ozone hole, WMO and its partners created and instituted guidelines designed to help with the observation networks, in support of the Montreal Protocol.
The goals of those regulations is to ensure broad, observational coverage, outline specific standards for operations, data processing and calibrations, and "foster a network where scientists meet, exchange knowledge, receive training and explore opportunities for collaboration," WMO said.
EarthCARE satellite orbits the planet. (European Space Agency)
That approach has "proven invaluable" to enact useful and policy-relevant documentation, one of the important results that show the success of the Montreal Protocol, according to an article contained in the bulletin that focused on measuring instruments and inter-comparison campaigns.
Report marked World Ozone Day
The publication of the latest WMO ozone bulletin coincided with World Ozone Day on Sept. 16, and the 40th anniversary of the Vienna Convention.
The convention made an important step towards ozone recovery by recognizing stratospheric ozone depletion as a worldwide issue, offering the structuring for the co-ordination of international teamwork in ozone research, systematic observations and scientific assessments.
“The theme for World Ozone Day [was] From Science to Global Action. It mirrors WMO’s 75th anniversary slogan, Science for Action. This is no coincidence,” said Celeste Saulo, WMO Secretary-General, in the news release.
“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."
WATCH: NASA records the seventh-smallest Antarctic ozone hole
Thumbnail showing the ozone hole over the Antarctic is courtesy of NASA Ozone Watch, taken in September 2024.
