Hole in ozone is larger than ever and only getting bigger – and scientists don’t know why

Ozone hole as of 2023 has surpassed its size of three years prior, scientists say

There is much less ozone at the centre of the ozone hole compared to nearly two decades ago, according to new study which suggests some yet-unknown chemicals may be damaging the Earth’s protective layer.

The ozone layer blankets the planet and protects the Earth from the Sun’s harmful ultraviolet radiation known to cause skin cancer.

When a hole in this protective layer was first discovered in 1985, it was quickly attributed to the presence of human-made chemicals in the atmosphere called chlorofluorocarbons (CFCs) widely used as refrigerants, propellants and aerosol applications and solvents.

The 1987 Montreal Protocol put heavy regulations across the globe on the production and consumption of CFCs, following which research groups began to notice the ozone layer slowly recovering.

But a new study, published in the journal Nature Communications, has found that the ozone hole above the Antarctic has been growing in size over the last few years.

“Most major communications about the ozone layer over the last few years have given the public the impression that the ‘ozone issue’ has been solved,” Hannah Kessenich, from the University of Otago in New Zealand said.

“While the Montreal Protocol has vastly improved our situation with CFCs destroying ozone, the hole has been amongst the largest on record over the past three years, and in two of the five years prior to that,” the researcher explained.

The new study found that the ozone hole as of 2023 has surpassed the size of the three years prior.

Late last month it was found to be over 26 million km² – nearly twice the area of Antarctica.

“This means that the hole is not only larger in area, but also deeper throughout most of spring,” researchers said.

However, scientists are not entirely sure what chemicals other than CFCs are damaging the ozone layer.

A previous study, published earlier this year, indicates some refrigerant chemicals other than CFCs may also be damaging the ozone layer.

The new research found that the recent drop in ozone is connected to changes in the air circulation patterns above Antarctica.

“This reveals the recent, large ozone holes may not be caused just by CFCs,” Ms Kessenich said.

Researchers caution that understanding the causes behind this change is important since the ozone layer over the Antarctic plays a major role in the Southern Hemisphere’s climate.

Since ozone absorbs ultraviolet radiation, a hole in the ozone layer not only causes extreme UV levels reaching the Earth, but can also drastically impact heat distribution in the Southern Hemisphere, they explain.

This could in turn affect people locally by altering wind patterns and surface climate, the study warned.