World Ozone Day commemorates 35 years of successful ozone layer protection

The World Meteorological Organization (WMO) joins the rest of the international community in marking World Ozone Day on 16 September. It highlights the importance of safeguarding the Earth’s protective ozone layer and shows that collective action, guided by science, is the best way to solve major global challenges. 

The adoption of the Montreal Protocol on Substances that Deplete the Ozone Layer 35 years ago marked a turning point in environmental history. The Protocol has become a symbol of what global cooperation can achieve if people unite and work together to protect the environment.  

On this thirty-fifth anniversary, we will remember how the Montreal Protocol ended one of the biggest threats ever to face humanity: the depletion of the ozone layer. When the world found out that man-made chemicals used in aerosol sprays and cooling were creating a hole in the sky, they came together.  

On 16 September 1987, governments adopted the Montreal Protocol to control and reduce ozone-depleting substances, mainly chlorofluorocarbons (CFCs) and halons. The Protocol came into effect in 1989. By 2008, it was the first and only UN environmental agreement to be ratified by every country in the world. With over 99 per cent of ozone-depleting substances now phased out, the ozone layer is healing. 

Because the ozone layer filters most of the harmful ultra-violet radiation from the sun, this action has protected millions of people from skin cancer and cataracts. It allowed vital ecosystems to survive and thrive. It slowed climate change: if ozone-depleting chemicals had not been banned, we would be looking at a catastrophic global temperature rise of an estimated 2.5°C by 2100.  

A recent study also estimated that without the Montreal Protocol ban on CFCs, less carbon would have been absorbed and stored in plants, vegetation and soil – Earth’s carbon sink – which might have led to an additional increase of 0.5 - 1ºC of global warming. 

The work on climate is far from done, however. Under the Kigali Amendment, which came into force in January 2019, nations have committed to phase down hydrofluorocarbons (HFCs) – potent greenhouse gases often used as replacements for the banned ozone-depleting substances in refrigerators and air-conditioners. Global compliance with the Kigali Amendment could avoid up to 0.4°C of global temperature rise by the end of the century.  

As the world grows hotter and the demand for cooling rises, we need to ensure that future cooling technologies are sustainable. The Protocol and its Kigali Amendment promote the adoption of climate-friendly and energy-efficient cooling technologies. This will potentially lead to additional climate and other benefits. For instance, by making cold chains more sustainable and available, food loss and waste would be reduced, further decreasing carbon emissions, as well as increasing food security. 

On this World Ozone Day, we celebrate the achievements of the Montreal Protocol: The Protocol that, through global cooperation, protected all living things, now and into the future.  

The most recent WMO and UN Environment Programme Scientific Assessment of Ozone Depletion, issued in 2018, concluded that the measures under the protocol will lead to the ozone layer on the path to recovery and to the potential return of the ozone in the Arctic and Northern Hemisphere mid-latitude ozone before the middle of the century (2035) followed by the Southern Hemisphere mid-latitude around mid-century, and Antarctic region by 2060. A new scientific assessment is due to be published later this year.