WMO Ozone and UV Bulletin No. 3 – September 2025

16 September 2025
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Key messages
  • Ozone layer remains on track to recovery in coming decades
  • WMO Ozone Bulletin says ozone hole in 2024 smaller than previous years
  • Vienna Convention and Montreal Protocol show benefits of science for global action
  • Stratospheric ozone protects people’s and planetary health
  • Continued atmospheric monitoring is vital
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The third edition of the WMO Ozone and UV Bulletin marks the 40th anniversary of the Vienna Convention and the 50th anniversary of WMO’s first global statement on the risks of ozone depletion. It highlights the continuing importance of systematic ozone and ultraviolet (UV) monitoring to protect human health, ecosystems, and food production.

The Bulletin reported that the low level of ozone depletion observed in 2024 was partly due to naturally occurring atmospheric factors which drive year-to-year fluctuations. However, the long-term positive trend reflects the success of concerted international action to ban ozone depleting chemicals that were once in widespread use.

These results underline how short-term variability can influence ozone levels, even as the long-term recovery of the ozone layer continues thanks to the success of the Montreal Protocol. The Bulletin emphasizes that WMO’s Global Atmosphere Watch Programme remains central to this effort, providing the observations, analysis, and capacity-building needed to track recovery and safeguard against emerging risks.

About the WMO Ozone and UV Bulletin series

The WMO Ozone and UV Bulletin is an annually issued scientific update that assesses the health of the ozone layer and UV radiation trends, highlighting recovery progress, challenges posed by extreme events, and the crucial need for continued monitoring and policy action.

More about this series