Ozone hole filling up, WMO says Earth could regain 1980s levels of protective shield by mid-century

The Earth’s protective ozone layer is on track to return to 1980s levels by the middle of this century, with the 2024 Antarctic ozone hole smaller than in recent years, the World Meteorological Organization (WMO) said in a new report.

The WMO Ozone Bulletin 2024 said lower ozone depletion this year was partly due to natural atmospheric factors but stressed the long-term improvement reflects the success of global action.

The bulletin was released on World Ozone Day, which also marked the 40th anniversary of the Vienna Convention that laid the foundation for international cooperation on ozone protection.

“Forty years ago, nations came together to take the first step in protecting the ozone layer, guided by science, united in action,” said UN Secretary-General Antonio Guterres.

“The Vienna Convention and its Montreal Protocol became a landmark of multilateral success. Today, the ozone layer is healing. This achievement reminds us that when nations heed the warnings of science, progress is possible,” he said.

The Montreal Protocol has already phased out more than 99 per cent of controlled ozone-depleting substances once widely used in refrigeration, air conditioning, firefighting foam and hairspray.

As a result, the ozone layer is projected to recover to 1980s levels by mid-century, reducing risks of skin cancer, cataracts, and ecosystem damage, the WMO bulletin said.

“The theme for World Ozone Day is From Science to Global Action. It mirrors WMO’s 75th anniversary slogan Science for Action. This is no coincidence,” said WMO Secretary-General Celeste Saulo.

Matt Tully, Chair of WMO’s Scientific Advisory Group on Ozone and Solar UV Radiation, said: “Despite the great success of the Montreal Protocol in the intervening decades, this work is not yet finished, and there remains an essential need for the world to continue careful systematic monitoring of both stratospheric ozone and of ozone-depleting substances and their replacements.”

The WMO said the total stratospheric ozone cover was higher than in previous years. The 2024 Antarctic ozone hole peaked with a maximum ozone mass deficit of 46.1 million tonnes on September 29, smaller than the large holes observed between 2020 and 2023.

Its onset was relatively slow, with delayed depletion in September followed by a rapid recovery.

“This persistent later onset has been identified as a robust indication of initial recovery of the Antarctic ozone hole,” the bulletin said.

(This is an agency copy. Except for the headline, the copy has not been edited by Firstpost staff.)