The World Meteorological Organization (WMO) has reported that the ozone layer is progressing towards long-term recovery. In its annual Ozone and UV Bulletin, the WMO investigates the effects of major volcanic eruptions and weather patterns on the Antarctic ozone hole for the year 2023. The bulletin indicates growing evidence that the ozone layer is on the road to recovery.
Research shows that in October and November 2023, there was a significant reduction in ozone loss compared to the previous year. The report notes that the eruption of the Hunga Tonga-Hunga Ha’apai volcano on January 15, 2022, increased water vapor levels in the stratosphere. However, this extra water vapor has minimally affected ozone depletion rates in the lower Antarctic stratosphere, a process primarily driven by sunlight and certain chemicals.
Nevertheless, the report mentions that the excess water vapor intensified depletion in the middle and upper layers of the atmosphere, especially near the periphery of the Antarctic stratospheric vortex, resulting in notable changes in ozone transport.
In the Southern Hemisphere, higher mid-latitude ozone levels recorded in 2023 marked an end to several years of low total ozone columns, which had been partially caused by the significant wildfires in Australia during 2020-2021 and the water vapor-related changes from the Hunga Tonga-Hunga Ha’apai eruption in 2022.
Additionally, the eruption propelled its ash and gas up to 55 kilometers high and led to a 5% reduction in the ozone layer over the tropical south-western Pacific and Indian Ocean regions within just one week.
The WMO report highlights that between January and July 2023, total ozone levels over Antarctica were below the average, facilitating an earlier identification of the ozone hole following standard detection methods. The initial low ozone levels likely influenced the total ozone column readings during the Antarctic spring, potentially linked to accelerated ozone depletion resulting from the volcanic eruption.
Looking ahead, researchers express optimism that if current protective measures are maintained, the ozone layer should recover to its 1980 levels—before the formation of the ozone hole—by 2066 in Antarctica, 2045 in the Arctic, and by 2040 elsewhere on the planet.