The World Meteorological Organization (WMO) has announced that the ozone layer is showing signs of long-term recovery. In its annual Ozone and UV Bulletin, the WMO assesses the effects of major volcanic eruptions and weather conditions on the Antarctic ozone hole for the year 2023.
The bulletin notes a significant reduction in ozone loss in October and November of 2023 compared to the previous year. It highlights the impact of the Hunga Tonga-Hunga Ha’apai volcano’s eruption on January 15, 2022, which introduced a large amount of water vapor into the stratosphere. Although this increased water vapor has slightly affected ozone depletion rates in the lower Antarctic stratosphere, the research indicates that it has intensified ozone loss in the middle and upper layers, particularly near the Antarctic stratospheric vortex.
The report states that the southern hemisphere experienced a rebound in total ozone levels in 2023, ending a trend of low ozone columns largely caused by the significant Australian wildfires in 2020 and 2021, as well as changes in ozone transport linked to the volcanic eruption’s excess water vapor. The eruption’s ash reached heights of up to 55 kilometers, leading to a 5% depletion of the ozone layer over the tropical southwestern Pacific and Indian Ocean regions within just one week.
Between January and July 2023, total ozone levels over Antarctica were below average, facilitating early detection of the ozone hole. The report suggests that these low levels affected ozone column readings into the Antarctic spring, potentially attributable to the eruption’s effect on mid-latitude stratospheric ozone depletion.
Despite these challenges, the research provides a positive outlook. If current global efforts continue, it is predicted that the ozone layer will recover to levels seen in 1980 by the year 2066 for the Antarctic, 2045 for the Arctic, and 2040 for other parts of the world.