According to a UN research, the Earth's ozone layer will recover in the next decades.

 By Oliver Milman

January 09, 2023 15.00 GMT

By 2040, the majority of the world's atmosphere, which shields the globe from UV radiation, is anticipated to have recovered completely.

Following resolute efforts by countries to phase out ozone-depleting compounds, the Earth's ozone layer hole, long the most feared environmental threat confronting humanity, is poised to be totally repaired over most of the planet within two decades, according to a new UN study.

The paper states that, with the exception of the polar areas, the depletion of the ozone layer, which ran the risk of exposing humanity to dangerous UV radiation from the sun, is on course to be fully recovered by 2040. The ozone layer will fully recover over the Arctic by 2045 and over the Antarctic by 2066. The poles will take a little longer.

Since the 1989 Montreal Protocol, an international agreement that helped eradicate 99% of ozone-depleting chemicals like chlorofluorocarbons (CFCs) that were used as solvents and refrigerants, the ozone layer has been slowly improving following alarm over the loss of ozone in the 1980s.

As greenhouse gases, CFCs could have increased global temperatures by up to 1C by the middle of the century, worsening an already dire situation where planet-heating gases are still not declining, according to the UN, the action taken to protect the ozone layer had also bolstered the more ponderous response to the climate crisis.

The World Meteorological Organization, which released the progress report on Monday, stated that "ozone action sets a precedence for climate action." The study is produced every four years. "Our accomplishment in eliminating ozone-eating compounds demonstrates what must be done immediately to move away from fossil fuels, cut greenhouse gas emissions, and hence limit temperature increase."

According to David Fahey, a scientist at the National Oceanic and Atmospheric Administration and a lead author of the new assessment, the Montreal agreement should be regarded as "the most successful environmental treaty in history and offers encouragement that countries of the world can come together, decide an outcome, and act on it."

The development has not always been straightforward; in 2018, scientists noticed an increase in CFC usage, which they finally traced to China and resolved. The replacement of CFCs by hydrofluorocarbons (HFCs), a different class of industrial chemicals, proved controversial since HFCs are greenhouse gases and needed a separate international agreement, reached in Kigali, to limit their usage.

Even with fast worldwide action against CFCs, according to Fahey, the chemicals continue to persist in the atmosphere for roughly a century. You just have to wait for nature to do its job and wash out these poisons, he added, comparing it to waiting for paint to dry.

He claimed that the challenge is even more difficult when it comes to greenhouse gases like carbon dioxide because they linger in the atmosphere for a much longer period of time and because, in contrast to CFCs, which were produced by a small number of companies, emissions from fossil fuels are much more pervasive and integrated into almost every aspect of human activity.

Several satellite photographs taken over a 21-year span show the ozone hole above Antarctica. Picture: Reuters

He noted that the lifespan of CO2 is "another order of magnitude, which is alarming." "A radically different problem is getting everyone on the earth to cease consuming fossil fuels,"

The most recent UN progress report is the first to examine how solar geoengineering, a proposed climate intervention in which reflecting particles, like sulphur, are sprayed in large quantities into the sky to reflect sunlight and hence reduce global heating, may affect the ozone layer.

Although the report acknowledges that "many knowledge gaps and uncertainties prevent a more robust evaluation at this time," it finds that the contentious practise, which the US government is looking to research, has the potential to lower global temperatures but could have "unintended consequences, including effects on ozone."

According to Fahey, adding a significant amount of sulphur to the stratosphere may diminish ozone, although most likely by less than 10% and without causing the ozone layer to "collapse."

These kinds of climate solutions are controversial because they include ethics and governance as well as science, the man added. But if you added enough sulphur to the air, there would be negative effects on ozone. It couldn't be avoided.