The year 2020 marks the 35th anniversary of the Vienna Convention for the Protection of the Ozone Layer. 

The Vienna Convention is a framework agreement adopted in 1985, setting out principles for cooperation and information sharing on the effects of human activities on the ozone layer. The Convention Secretariat reports that it was the first convention of any kind to be signed by every country involved, and it reached universal ratification in 2009.

In a message on 16 September 2020, the International Day for the Preservation of the Ozone Layer, UN Secretary-General António Guterres said the Convention was the first step in fixing the hole in the Earth’s ozone layer. He highlighted that few global agreements have been as successful as this one has been. The Convention’s Montreal Protocol has facilitated phasing out the gases that caused the ozone hole, which were used in aerosols and cooling appliances. The UN Environment Programme (UNEP) reports that the ozone layer is expected to return to pre-1980 values by mid-century.

The next step, the Secretary-General said, is to find new alternatives for the ozone-depleting substances, since replacements themselves are now known to contribute to global warming. This is the focus of the Montreal Protocol’s most recent agreement, the Kigali Amendment, which came into force in January 2019. It calls for reducing the production and consumption of hydrofluorocarbons (HFCs) by more than 80% over the next 30 years.

In her message on the International Day, UNEP Executive Director Inger Anderson said that if fully implemented, the Kigali Amendment will prevent 0.4°C of global warming. [Message of UN Secretary-General] [Message of UNEP Executive Director]