WMO Bulletin shows recovery of ozone layer, driven by science

The WMO Ozone 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.

The WMO Ozone Bulletin was issued for World Ozone Day on 16 September and the 40th anniversary of the Vienna Convention, which recognized stratospheric ozone depletion as a global problem and provided the framework for mobilizing international cooperation in ozone research, systematic observations and scientific assessments.

“Forty years ago, nations came together to take the first step in protecting the ozone layer — guided by science, united in action,” said United Nations Secretary-General António Guterres.

“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,” he said.

To date, the Montreal Protocol has led to the phase-out of over 99% of the production and consumption of controlled ozone-depleting substances, which were used in refrigeration, air conditioning, firefighting foam and even hairspray. As a result, the ozone layer is now on track to recover to 1980s levels by the middle of this century, significantly reducing risks of skin cancer, cataracts, and ecosystem damage due to excessive UV exposure.

“The theme for World Ozone Day is From Science to Global Action. It mirrors WMO’s 75th anniversary slogan Science for Action. This is no coincidence,” said WMO Secretary-General Celeste Saulo.

“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,” she said.