The Antarctic ozone hole is getting smaller, bigger, and might take longer to heal. The mesosphere is involved: Review

Antarctic ozone hole now larger, thinner & may take longer to recover. Mesosphere has a role to play: Study

Based on a new study, the ozone hole above the Antarctic has gotten thinner and bigger over the majority of spring. 

The Antarctic ozone hole has been huge in the previous four years, despite recovering in area and depth since the 2000s, according to a study published in Nature Communications. 

Compared to 19 years ago, there is significantly less ozone in the heart of the ozone hole. Lead author Hannah Kessenich of the University of Otago told Down To Earth, "We find that the concentration of ozone at the centre of the ozone hole has reduced, which means the ozone layer has notably thinned."

The stratosphere, on the other hand, over the Antarctic has an area known as the "ozone hole," where the amount of ozone is abnormally low. August through October mark the start of the Southern Hemisphere's spring season.

The UN Environment Programme (UNEP) estimates that the ozone layer will rebound in forty years.

Yet, the ozone hole has grown noticeably between 2020 and 22. According to the report, the size and duration of the 2022 hole were strikingly similar to those of the significant holes in 2020 and 2021.

While data up to 2022 were included in the investigation, 2023 also demonstrates the similar pattern. NASA reports that the hole was the 16th largest over the period of September 7–October 13, averaging 23.1 million square kilometres, or roughly the size of North America.

Still, that is not the only issue. The climate and dynamics of the Southern Hemisphere are inextricably related to the ozone layer over the Antarctic. 

We soon saw that adding these years to the observational record affected earlier trends towards ozone recovery because of the exceptionally large Antarctic ozone holes that occurred between 2020–2022. This prompted us to investigate the matter more and ascertain the precise location and time at which ozone depletion was becoming more severe. Kessenich clarified.

Thus, from 2004 through 2022, the team examined the daily and monthly variations in ozone at various latitudes and elevations within the Antarctic ozone hole.

Between 2004 and 2022, the researchers saw a total decrease of 26% near the centre of the ozone hole. 

This decrease occurs in spite of the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, which controls the manufacturing and use of substances produced by humans that are known to lower ozone levels. 

Nearly 99 percent of the compounds that are prohibited from depleting ozone have been phased out, according to the 2022 quadrennial assessment report of the Montreal Protocol on Ozone Depleting compounds. 

According to the UNEP, variations in the Antarctic ozone hole's magnitude between 2019 and 2021 may have been mostly caused by meteorological factors.

Other known contributing elements include springtime temperatures and wind patterns, volcanic eruptions and wildfire aerosols, variations in the solar cycle, and the establishment of an ozone hole.