WMO Bulletin Reports Ozone Layer Recovery and Highlights Ongoing Monitoring Needs

The bulletin coincides with World Ozone Day, celebrating the success of the Montreal Protocol, which has helped phase out harmful ozone-depleting substances.

The World Meteorological Organization (WMO) has released its annual Ozone and UV Bulletin, offering insights into the state of the ozone layer and ongoing measures to protect human health and the environment from harmful ultraviolet radiation. The bulletin coincides with World Ozone Day, celebrating the success of the Montreal Protocol, which has helped phase out harmful ozone-depleting substances.

The 2023 bulletin examines meteorological factors, including a major volcanic eruption, that influenced the Antarctic ozone hole this year. It reports that despite challenges, the ozone layer continues on a path to long-term recovery, supported by the declining presence of ozone-depleting substances such as chlorine and bromine in the atmosphere.

The phaseout of these substances also brings climate benefits, as many are potent greenhouse gases. The WMO stressed the need for continued global monitoring to ensure progress continues.

“The ozone layer, once an ailing patient, is on the road to recovery,” said UN Secretary-General António Guterres. He also highlighted the role of the Montreal Protocol's Kigali Amendment, which addresses hydrofluorocarbons (HFCs), powerful greenhouse gases, as critical to further climate action.

If current policies remain in place, the ozone layer is expected to recover to 1980 levels by 2066 over Antarctica, 2045 over the Arctic, and 2040 for the rest of the world. Since 2000, the Antarctic ozone hole has shown gradual improvement in both size and depth.

The 2023 Antarctic ozone hole had two notable characteristics: an early onset in August and persistence into December. The eruption of the Tonga Hunga Tonga-Hunga Ha’apai volcano in January 2022 affected the ozone layer by altering stratospheric water vapor levels and ozone transport patterns.

The WMO emphasized the need to maintain high-quality scientific observations, such as those conducted under the Global Atmosphere Watch (GAW) Programme, to monitor and understand the variability in the ozone layer. As Matt Tully, Chair of the WMO Scientific Advisory Group on Ozone and UV Radiation, explained, ongoing research and data collection are essential for ensuring the ozone's recovery continues as expected.

The Ozone and UV Bulletin also reported on the most recent Ozone Research Managers meeting, which called for continued efforts in five key areas: research, systematic observation, controlled substance coverage, data stewardship, and capacity-building. The WMO plays a pivotal role in advancing these efforts to safeguard the ozone layer for future generations.