The ozone layer, which protects the Earth from harmful solar radiation, is ” on the right track “ to recover in four decades, but geoengineering projects to limit global warming could threaten this progress, scientists warn on Monday, January 9.
“The phasing out of almost 99% of banned substances that destroy ozone has helped to preserve the ozone layer and contributed significantly to its recovery in the upper stratosphere and to a reduction in human exposure to radiation. harmful ultraviolet (UV) rays from the sun »note these experts, who publish their four-year estimate under the aegis of the UN.
And if we talk again about the hole in the ozone layer…
The hole in the ozone layer was created by man-made pollution, particularly by chlorofluorocarbons (CFCs) once emitted by many refrigerators.
Reduction of hydrofluorocarbons
Over the past few decades, however, global cooperation has given the ozone layer a chance to recover. The Montreal Protocol (Canada), signed in 1987 and ratified by 195 countries, greatly reduced the amount of CFCs in the atmosphere, and the ozone layer thus seemed to be able to recover completely, according to UN estimates.
“If current policies remain in place, the ozone layer is expected to recover to 1980 values (before the ozone hole appeared) by about 2066 over Antarctica, 2045 above above the Arctic and 2040 in the rest of the world »says the UN Environment.
Paul Crutzen, the chemist who saved the world
In 2016, the Kigali agreement also provided for the phasing out of hydrofluorocarbons (HFCs), extremely harmful gases for the climate used in refrigerators and air conditioners. If the agreement is respected, it could reduce global warming by 0.5°C by 2100, experts have already estimated.
“A lot of uncertainties”
However, the latter also looked for the first time at the potential effects on ozone of geo-engineering projects intended to limit global warming, warning against their undesirable effects.
The idea would be to intentionally add aerosols to the stratosphere to reflect some of the sun’s rays. One such project would be to inject billions of sulfur particles into the upper layer of the atmosphere.
Making clouds, whitening the surface of the globe… 13 (more or less) crazy projects to save the planet
An injection of particles into the atmosphere “could result in a serious drop in ozone levels”warns John Pyle, co-chairman of the scientific panel working on ozone on behalf of the UN. “There are a lot of uncertainties”according to him.
