The Antarctic mid-spring ozone hole has been growing over the past 20 years, according to the study

Antarctica’s mid-spring ozone hole has grown over the past 20 years, a new study finds.

The ozone layer over Antarctica has declined by 26 percent since 2004, says the new study published in Nature communication Reported, a finding that contradicts the previously reported recovery trend in the ozone hole. However, not all experts are convinced of the new findings.

The ozone layer protects life on Earth from the sun’s ultraviolet rays. The thinner the ozone layer, the greater the danger of these rays. This puts people at risk of skin cancer, sunburn and cataracts. Every year in mid-spring, around September in the Southern Hemisphere, the ozone layer over Antarctica becomes thinner. The layer does not disappear completely, but its concentrations fall below a certain threshold. This creates the so-called ozone hole.

However, there is evidence that the ozone layer is recovering. In the winter months of 2005 to 2016, scientists found a 20 percent decrease in ozone rarefaction. Scientists estimate that this ozone hole will recover by 2040.

But new research led by Annika Seppälä and Hannah Kessenich from the University of Otago in Dunedin, New Zealand, suggests otherwise.

The researchers analyzed monthly and daily changes in ozone between 2001 and 2022, looking at different layers of the stratosphere during the key period September to November, when the layer is thinnest.

Analyzing satellite data from 2022, researchers concluded that these previously reported recovery trends had disappeared.

The restoration of the ozone layer is largely due to the Montreal Protocol, introduced in 1987, which regulates the amount of ozone-depleting substances that can be released into the atmosphere.

This new paper points out that between 2020 and 2022, large ozone holes occurred again over Antarctica in the spring, in September.

However, not all scientists agree with the results of this new research.

Martin Jucker, Ph.D., senior lecturer at the University of New South Wales’ Climate Change Research Center and associate investigator at the Australian Research Council’s Center of Excellence for Climate Extremes, said in a statement he was “not convinced” by the results Study.

“Their results depend heavily on the large ozone holes we saw in 2020-2022.” Jucker said. “However, existing literature has already found reasons for these large ozone holes: smoke from the 2019 bushfires and a volcanic eruption (La Soufriere), as well as a general connection between the polar stratosphere and the El Niño Southern Oscillation: we know that during La In Niña- In some years, the polar vortex in the stratosphere tends to be stronger and colder than usual, meaning that ozone concentrations will also be lower in these years. There was a rare triple La Niña in 2020-22, but this connection is never mentioned in the study. “

Newsweek asked Seppälä and Kessenich via email for comment on Jucker’s observations.

Jucker was also concerned that the study shortens the record period analyzed by two years. The researchers did not analyze the years 2002 and 2019 because there was a “sudden warming of the stratosphere” that dissolved the ozone hole “unusually early in these years.”

“These events have been shown to greatly reduce the size of the ozone hole, so including these events would likely have reversed any long-term negative trend in ozone concentrations. It is questionable how the authors can delete 2002 and 2019 from the records, but not 2020. “-22, considering that all of these years were demonstrably marked by very special and rare events,” said Jucker.

“In this context, it is important to note that the ozone hole is extremely variable from year to year, meaning that it can be large in one year and small in another year. A trend can only be recognized over longer periods of time.” “Just 22 years and the exclusion of two unfavorable years do not help to make this study convincing.”