The United Nations weather organization reports that the ozone layer is on a path to long-term recovery.
The World Meteorological Organization (WMO) has released its annual Ozone and UV Bulletin, which assesses the effects of notable volcanic eruptions and weather conditions on the Antarctic ozone hole for 2023. The report underscores the growing evidence that the ozone layer is set for a sustained recovery.
Research indicates that in October and November 2023, ozone loss was significantly lower compared to 2022. The study mentions the pivotal eruption of the Hunga Tonga-Hunga Haʻapai volcano on January 15, 2022, which introduced additional water vapor into the stratosphere. This increase has had a minimal effect on ozone depletion rates in the lower Antarctic stratosphere, a process mainly driven by sunlight and certain chemicals. However, the excess water vapor has intensified depletion in the middle and upper layers of the stratosphere, particularly near the Antarctic polar vortex’s edge.
The eruption caused certain changes in ozone transport. The report notes that in the southern hemisphere, higher mid-latitude ozone levels in 2023 ended multiple years of low total ozone levels, a situation partly caused by significant Australian wildfires in 2020 and 2021 and changes in ozone transport due to water vapor from the volcanic eruption.
Furthermore, the eruption’s plume reached altitudes of up to 55 kilometers and led to a 5% reduction in the ozone layer over the tropical southwestern Pacific and Indian Ocean regions within just one week.
The WMO report also indicated that from January to July 2023, total ozone levels over the Antarctic were below average, which resulted in an earlier identification of the ozone hole based on standard detection methods. These lower initial ozone levels likely affected total ozone column levels during the Antarctic spring, potentially linked to increased mid-latitude stratospheric ozone depletion following the Hunga Tonga-Hunga Haʻapai eruption.
Nevertheless, there is optimism. The research suggests that if existing measures remain in place, the ozone layer is expected to return to its 1980 levels, before the emergence of the ozone hole, by 2066 for Antarctica, 2045 for the Arctic, and 2040 for the rest of the world.