A new United Nations assessment finds that the hole in the ozone layer, once the most significant environmental hazard facing humanity, will be fully healed in most parts of the world within two decades after decisive action by governments to phase out ozone-depleting substances. .
was submitted the reportprepared by a UN-supported panel of experts, Monday, at the 103rd annual meeting of the American Meteorological Society.
The assessment report, published every four years, issued by the UN-supported Scientific Assessment Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer, confirms that the phase-out of about 99 per cent of banned substances has succeeded in protecting 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 recover to what it was in 1980 (before the ozone hole appeared) by approximately 2066 over the Antarctic, by 2045 over the Arctic, and by 2040.” to the rest of the world.
Variations in the size of the Antarctic ozone hole, especially between 2019 and 2021, were largely driven by weather conditions.
However, the Antarctic ozone hole has been slowly improving in area and depth since 2000.
“It is great that the ozone recovery is on track, according to the latest quadrennial report,” said Meg Seki, Executive Secretary of the Ozone Secretariat at the United Nations Environment Programme, noting that “assessments and reviews by the Scientific Assessment Panel are helping policy-makers and decisions.”
The United Nations indicated that the new report confirms the importance of the Montreal Protocol to mitigate 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 entered into force in 1989.
An additional 2016 agreement, known as the Kigali Amendment to the Montreal Protocol, requires a gradual reduction in the production and consumption of certain hydrofluorocarbons (HFCs).
HFCs do not directly deplete ozone, but rather are powerful climate-altering gases. The Scientific Assessment Panel said that this adjustment estimates a warming of 0.3-0.5°C could be averted by 2100 (and this does not include contributions from HFC-23 emissions).
For the first time, the Scientific Assessment Panel examined the potential effects on ozone from 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 climate warming, by increasing the reflection of sunlight.
However, the team warns that the unintended consequences of stratospheric aerosol injection (SAI) “could also affect stratospheric temperatures, the stratospheric cycle and ozone production, destruction and transport rates”.