The United Nations’ weather agency reports that the ozone layer is on a path towards long-term recovery. The World Meteorological Organization (WMO) has released its annual Ozone and UV Bulletin, which assesses the effects of significant volcanic eruptions and weather conditions on the Antarctic ozone hole for 2023.
The report indicates emerging evidence that the ozone layer is set for a sustained recovery. Research shows that there was a noticeable reduction in ozone loss during October and November 2023 compared to the previous year.
The report notes that the significant eruption of the Hunga Tonga-Hunga Haʻapai volcano on January 15, 2022, increased water vapor in the stratosphere. Current studies suggest that while this additional water vapor has had a minor effect on ozone depletion in the lower Antarctic stratosphere—which occurs due to sunlight and specific chemicals—it has accelerated depletion in the middle and upper layers, especially near the Antarctic stratospheric vortex.
Moreover, the eruption caused changes in ozone transport. The report states that the higher ozone levels in the southern hemisphere for 2023 marked an end to several years of low ozone columns, influenced partly by large wildfires in Australia during 2020-2021 and the impact of the water vapor from the volcanic eruption.
Data indicate that the eruption’s emissions reached heights of up to 55 kilometers, leading to a 5% depletion of the ozone layer over the tropical south-western Pacific and Indian Ocean regions within just one week.
Furthermore, the WMO report observed that from January to July 2023, total ozone levels over Antarctica were below average, facilitating the early detection of the ozone hole. These lower initial levels have affected ozone column levels into the Antarctic spring and may be linked to accelerated ozone depletion at mid-latitudes due to the volcanic eruption.
Encouragingly, the research predicts that if current protective practices remain in place, the ozone layer could return to its pre-1980 levels by 2066 in Antarctica, 2045 in the Arctic, and 2040 globally.