The ozone layer is on its way to recovery

The hole, discovered in the 1980s, could be swallowed within ten to forty years, according to the United Nations. The +2°C target in Paris is still slipping away.

Scientists warned on Monday (9 January) that the hole in the ozone layer could be reduced within four decades, but potential solar geoengineering projects to limit global warming could have unintended effects.

If current policies continue, the ozone layer is expected to return to 1980 values ​​(before the hole appeared) over Antarctica by about 2066, over the Arctic by 2045, and over the rest of the world by 2040.”, shows the UN Environment in its four-year calculation.

Recovery through international cooperation

The phase-out of almost 99% of banned ozone-depleting substances has helped protect the ozone layer and contributed significantly to its recovery in the upper stratosphere and to reducing human exposure to harmful ultraviolet (UV) rays from the sun.“, mention UN-mandated experts.

The hole in the ozone layer was created by man-made pollution, especially chlorofluorocarbons (CFCs), which were once emitted by many refrigerants. In recent decades, global cooperation has given it a chance to rebuild itself. The Montreal Protocol (Canada), signed in 1987 and ratified by 195 countries, has significantly reduced the amount of CFCs in the atmosphere and the ozone layer can be completely restored, according to UN estimates.

Fears around geoengineering

The 2016 Kigali agreement also called for the phase-out of hydrofluorocarbons (HFCs), extremely climate-damaging gases used in refrigerators and air conditioners. Experts estimate that if the agreement is followed, it could reduce global warming by 0.5°C by 2100.

However, the latter was also the first to examine the potential effects on ozone of geo-engineering projects intended to limit global warming and warned against their unwanted effects. The idea would be to deliberately add particles suspended in the stratosphere to reflect some of the sun’s rays. One of these projects involves injecting large amounts of sulfur particles into the upper atmosphere.

These technologies would somehow replicate a volcanic eruption similar to the 1991 eruption of Mount Pinatubo in the Philippines, which would lower temperatures by 1°C. John Pyle, co-chair of the UN’s scientific panel on ozone, notes that ozone levels have been affected in subsequent years.

Injecting particles into the atmospherecan cause serious ozone depletion” he warns.There are many uncertainties“, according to his words.

Paris’ goal is to get away

The planet has gained about 1.2°C since the pre-industrial era, already causing an increase in heat waves, floods and storms. The international community is committed to limiting this warming to well below 2°C, preferably well below 1.5°C. But current policies point to a temperature rise of 2.8°C by the end of the century, well above the limits of the Paris Agreement, according to the United Nations.

Geo-engineering projects are sometimes touted as a time-saving solution, but scientists have already warned of the dangers associated with these technologies. Intentional modification of solar radiation, for example, could disrupt the monsoon regime in South Asia and West Africa, thereby destroying crops on which hundreds of millions of people depend, according to already published studies.

“The easiest thing to do is to stop the emission of greenhouse gases”

What will happen if the radiation modification ends?for some reason the surface temperature is very likely to rise rapidly“says the IPCC.

Particle injection over Antarctica has been simulated with mixed results. This would certainly reduce global temperatures by 0.5°C over two decades, but the hole in the ozone layer would return to near-1990s levels.The easiest thing to do is to stop releasing greenhouse gases into the atmosphere“, John Pyle emphasized. “And it’s hard“.

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