The World Meteorological Organization (WMO) has reported that the ozone layer is on a promising path toward long-term recovery. In its annual Ozone and UV Bulletin, the WMO analyzed how significant volcanic eruptions and weather patterns influenced the Antarctic ozone hole in 2023. The findings indicate a reduction in ozone loss during October and November 2023 when compared to the previous year.
One notable eruption, the Hunga Tonga-Hunga Ha’apai volcano on January 15, 2022, added considerable water vapor to the stratosphere. This increase has had a minimal effect on ozone depletion in the lower Antarctic stratosphere but has been linked to enhanced depletion in the middle and upper layers, particularly near the Antarctic stratospheric vortex.
The eruption’s impact was seen in the southern hemisphere, where higher ozone levels this year have ended a multi-year trend of low total ozone columns, which were partly caused by devastating wildfires in Australia in 2020-2021 and transport changes in ozone linked to the excess water vapor from the volcanic eruption.
Research indicates that the fumes from the Hunga Tonga-Hunga Ha’apai eruption reached up to 55 kilometers into the atmosphere, leading to a quick reduction of 5% in the ozone layer over regions of the tropical southwestern Pacific and Indian Ocean.
Between January and July 2023, ozone levels over Antarctica were below average, allowing for an early identification of the ozone hole. These lower initial levels may be tied to the eruption’s impact, which accelerated ozone depletion in the mid-latitude stratosphere.
Despite these challenges, researchers are optimistic. If current protective measures are maintained, the ozone layer is expected to recover to its 1980 levels—before the onset of the ozone hole—by 2066 in Antarctica, 2045 in the Arctic, and 2040 globally.