The United Nations’ weather agency has announced that the ozone layer is expected to recover in the long term. According to the latest WMO Ozone and UV Bulletin from the World Meteorological Organization (WMO), which analyzes the effects of significant volcanic eruptions and weather conditions on the Antarctic ozone hole in 2023, there is strong evidence supporting this positive outlook.
The report indicates that less ozone depletion was recorded in October and November 2023 compared to the same period in 2022. The Hunga Tonga-Hunga Ha’apai volcano, which erupted on January 15, 2022, contributed to an increase in water vapor in the stratosphere. However, research shows that this additional water vapor had only a minor effect on ozone depletion at lower altitudes in the Antarctic stratosphere, a process primarily driven by sunlight and specific chemicals.
Nonetheless, the excess water vapor did accelerate ozone depletion in the mid and upper parts of the stratosphere, particularly near the Antarctic stratospheric vortex. The report also noted that the southern hemisphere witnessed a rise in ozone levels in 2023, ending several years of low totals that were partly due to the severe Australian wildfires in 2020 and 2021, along with variations in ozone transport linked to the volcanic eruption.
Additionally, the eruption’s gases were propelled as high as 55 kilometers, causing a 5% reduction in the ozone layer over tropical regions in the southwestern Pacific and Indian Ocean within just one week. Between January and July 2023, total ozone levels over Antarctica were reported to be below average, facilitating early detection of the ozone hole based on standard criteria. This early dip in ozone levels may be tied to the accelerated depletion caused by the Hunga Tonga-Hunga Ha’apai eruption.
Despite these challenges, there is optimism for the future. Continuing current protective practices could lead to a restoration of the ozone layer to its 1980 levels (before the onset of the ozone hole) by 2066 in the Antarctic, 2045 in the Arctic, and 2040 globally.