A new UN assessment finds that the hole in the ozone layer, once the most significant environmental danger to humanity, will be completely healed in most of the world within two decades after decisive action by governments to phase out substances that deplete the ozone layer. .
it was presented the reportprepared by a UN-backed panel of experts at the 103rd annual meeting of the American Meteorological Society on Monday.
The assessment report, published every four years, issued by the Scientific Evaluation Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer backed by the United Nations, confirms that the phasing out of about 99% of banned substances has succeeded in protect the ozone layer, leading to its remarkable recovery. In the upper stratosphere, human exposure to harmful ultraviolet radiation from the sun decreases.
Promising expectations
The report notes that “if current policies remain in place, the ozone layer is expected to return to what it was in 1980 (before the ozone hole appeared) by about 2066 over Antarctica, by 2045 over the Arctic and by 2040”. to the rest of the world.
Changes in the size of the Antarctic ozone hole, particularly between 2019 and 2021, have been largely driven by weather conditions.
However, since 2000 the Antarctic ozone hole has been slowly improving in area and depth.
“It’s great that ozone recovery is on track, according to the latest four-year report,” said Meg Seki, executive secretary of the Ozone Secretariat at the United Nations Environment Program, noting that “assessments and the scientific assessment panel reviews are helping policy makers and decisions.”
The United Nations has indicated that the new report confirms the importance of the Montreal Protocol in mitigating the effects of climate change and the positive impact of the treaty.
The Montreal Protocol is a global agreement to protect the planet’s ozone layer by phasing out chemicals that deplete it. This historic agreement went into effect in 1989.
A further 2016 agreement, known as the Kigali Amendment to the Montreal Protocol, calls for a gradual reduction in the production and consumption of some hydrofluorocarbons (HFCs).
HFCs do not directly deplete ozone, but are quite potent climate-altering gases. The Science Assessment Panel said this adjustment estimates that 0.3-0.5°C of warming could be avoided by 2100 (and this does not include contributions from HFC-23 emissions).
For the first time, the scientific assessment team looked at the potential effects on ozone of the deliberate addition of aerosols to the stratosphere, known as stratospheric aerosol injection (SAI).
Stratospheric aerosol injection (SAI) has been suggested as a possible way to reduce global warming by increasing the reflection of sunlight.
However, the team cautions that the unintended consequences of stratospheric aerosol injection (SAI) “could also affect stratospheric temperatures, the stratospheric cycle, and rates of ozone production, destruction and transport.”
