By Giulia D'Alessandro
After decades of depletion, the ozone layer is on its way to a full recovery. In the next four decades the restoration of the ozone layer to pre-1980s level will help fight climate change by lowering the overall global temperature by 0.5 °C. This is the most impactful takeaway of UN-backed panel of experts presented at the American Meteorological Society’s 103rd annual meeting, held in Denver (USA) from 8th to 12th January 2023.
The UN-backed Scientific Assessment Panel to the Montreal Protocol assessment report, published every four years, confirms the disappearance of nearly 99% of banned ozone-depleting substances. It has been demonstrated that the decline in the emission of chemicals referred to as ozone depleting substances (ODS) due to compliance with the Montreal Protocol will avoid global warming of approximately 0.5 – 1 °C by mid-century. The Montreal Protocol on Ozone Depleting Substances, adopted on 16th September 1987, is the landmark multilateral environmental agreement that regulates the production and consumption of ODSs. The Montreal protocol has thus succeeded in safeguarding the ozone layer, leading to a major recovery in the stratosphere and decreased human exposure to harmful UV rays from the sun.
If current policies remain in place, the ozone layer is expected to recover to the values it had before the appearance of the ozone hole by around 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the world.
“The impact the Montreal Protocol has had on climate change mitigation cannot be overstressed. […] The assessments and reviews undertaken by the Scientific Assessment Panel remain a vital component of the work of the Protocol that helps inform policy and decision makers” said Meg Seki, Executive Secretary of the United Nations Environment Programme’s Ozone Secretariat.
Even though ODSs are not directly responsible for the increase in temperature, saving the ozone layer has had a positive knock-on effect on global warming, as suggested by the UN report, because some of the harmful chemicals that were phased out are hydrofluorocarbons (HFCs): powerful greenhouse gasses which contribute to global warming.
It is thus safe to say that the United Nations’ ozone action sets a precedent for climate action. The success of this operation shows what must be done to transition away from fossil fuels. The challenge when it comes to greenhouse gasses like carbon dioxide is even greater as they stay in the atmosphere far longer. Unlike CFCs which were produced by just a handful of companies in the 1980s, the emissions coming from fossil fuels are far more widespread and embedded in almost every activity in society. The success of the measures implemented by the Montreal Protocol proves that a real inversion of the process of climate change is possible.