And now for a spot of good news: the protective layer of ozone continues to heal, with the hole in our stratospheric shield having shrunk to a smaller size in 2024 than in the period between 2020-2023.
That means we're moving towards regaining the ozone layer's global coverage and protection from the harmful ultraviolet radiation released by the Sun. According to the World Meteorological Organization (WMO), a United Nations agency that assesses ozone depletion, this is the result of decades of international cooperation in limiting the emission of greenhouse gases.
In fact, the WMO issued a bulletin on September 16 to mark the 40th anniversary of the Vienna Convention. This was an agreement made in 1980 between dozens of countries (it's now up to 116) which provided the framework for mobilizing efforts worldwide to study the ozone layer. It was followed by the Montreal Protocol in 1987, a treaty that saw participating countries phase out the production of substances responsible for depleting the ozone layer.
Thanks to the Montreal Protocol, over 99% of the production and consumption of controlled ozone-depleting substances like chlorofluorocarbons (CFCs) – which found use in refrigeration, air conditioning, and aerosol spray products – have been phased out. The WMO notes that if we keep this up, the ozone layer could recover to 1980s levels by the middle of the 21st century. That could drastically reduce risks of skin cancer, cataracts, and ecosystem damage that are typically caused by excessive ultraviolet radiation exposure.
The depth of the 2024 Antarctic ozone hole – which appears over the Antarctic each year in spring and shows especially dramatic thinning of the ozone layer – was below the 1990–2020 average. That's a big win for the environment.
The report also highlights that we're making progress in fighting climate change on another major front. The 2016 Kigali Amendment to the Montreal Protocol, which commits countries to phasing out hydrofluorocarbons (HFCs) – greenhouse gases that don't harm the ozone layer like CFCs, but still trap heat in the atmosphere – has been ratified by 164 parties so far. With that, we're on track to avoid up to 0.5 °C of global warming by the end of this century.
Based on its assessments in 2022, the WMO estimates that the ozone layer could recover to pre-ozone hole values (the aforementioned 1980s state) by 2066 over the Antarctic, by 2045 over the Arctic and by 2040 for the rest of the world. Its next assessment will be in 2026; hopefully the international community will continue to honor and extend its commitment to limiting harmful emissions in the coming years to make those expectations a reality.
Find the WMO's full report here.
