Ozone recovery continues
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The WMO says the ozone layer is showing signs of recovery despite disruptions caused by a major volcanic eruption.
According to the World Meteorological Organization (WHO) 2023 Ozone and UV Bulletin, the eruption of Tonga’s Hunga Tonga-Hunga Ha’apai volcano in January 2022 introduced additional water vapour into the stratosphere, temporarily affecting ozone distribution.
However, the overall trend remains positive, with levels of harmful ozone-depleting chemicals, such as chlorine and bromine, continuing to decline.
The report notes that efforts under the Montreal Protocol, a global treaty aimed at phasing out substances harmful to the ozone layer, are having the desired effect.
António Guterres, UN Secretary-General, described the recovery as a hopeful sign of international cooperation, calling the ozone layer “an ailing patient on the road to recovery.”
Despite the challenges posed by natural events like the volcanic eruption, experts believe that the depletion of ozone-depleting substances has now peaked, and recovery is progressing.
If current policies remain effective, the ozone layer is expected to return to 1980 levels by 2066 over Antarctica, 2045 over the Arctic, and 2040 for the rest of the world.
WMO authorities emphasised the importance of continuing scientific monitoring and maintaining vigilance against complacency.
The phaseout of chemicals like hydrofluorocarbons (HFCs), which also contribute to climate change, represents a significant environmental success.
Experts say there is a need for ongoing global monitoring to understand atmospheric changes and support future recovery.
The WMO report further highlights the unpredictable nature of atmospheric events, with the 2023 Antarctic ozone hole behaving unusually, marked by an early onset in August and an unusually persistent state through December.
Despite these anomalies, the evidence continues to support that the ozone layer is on the path to recovery.