The United Nations weather agency has announced that the ozone layer is on a promising path toward long-term recovery.
The World Meteorological Organization (WMO) has released its annual Ozone and UV Bulletin, which assesses how major volcanic eruptions and weather conditions have influenced the Antarctic ozone hole in 2023. The report provides compelling evidence that the ozone layer is recovering.
Research indicates that ozone loss in October and November 2023 was significantly less than in the same period in 2022. The report mentions the impact of the Hunga Tonga-Hunga Ha’apai volcano eruption on January 15, 2022, which increased water vapor levels in the stratosphere. While the added water vapor has had a minimal effect on the rate of ozone depletion in the lower Antarctic stratosphere—where depletion is triggered by sunlight and specific chemicals—it has contributed to some depletion in the middle and upper layers, particularly near the Antarctic stratospheric vortex.
The eruption also altered ozone transport patterns. In the Southern Hemisphere, the increased mid-latitude ozone values in 2023 ended a several-year period of low total ozone columns, which had been partly caused by the significant wildfires in Australia in 2020 and 2021, as well as the ozone transport alterations due to the volcanic eruption’s excess water vapor.
According to the research, the eruption’s ash reached altitudes of up to 55 kilometers, leading to a 5% reduction in ozone levels over the tropical southwestern Pacific and Indian Ocean within just one week. Additionally, from January to July 2023, total ozone levels over Antarctica were below average, which allowed for an early detection of the ozone hole based on standard methods.
These low initial levels affected total ozone column levels in the Antarctic during the spring, potentially linked to the accelerated ozone depletion caused by the Hunga Tonga-Hunga Ha’apai eruption.
Encouragingly, researchers assert that if current practices remain in place, the ozone layer is projected to return to levels seen in 1980—before the formation of the ozone hole—by 2066 in Antarctica, 2045 in the Arctic, and 2040 globally.