International Actions to Protect the Ozone Layer
The international treaty called The Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) is gradually eliminating the production and consumption of ozone-depleting substances to limit their damage to the earth’s ozone layer. The Montreal Protocol is signed by 197 countries – the first treaty in the history of the United Nations to achieve universal ratification – and is considered by many the most successful environmental global action.
The United States signed the Montreal Protocol in 1987, and has been a leader in guiding the successes of the treaty. From the beginning, EPA has been a proud contributor to the broad coalition that developed and implemented flexible, innovative, and effective approaches to protect the stratospheric ozone layer. In 1995, the United Nations named September 16 the International Day for the Protection of the Ozone Layer, also known as World Ozone Day.
The Montreal Protocol celebrated its 35th anniversary in 2022. Learn about the history of the Montreal Protocol and its implementation in the United States in the 2017 report Stratospheric Ozone Protection: 30 Years of Progress and Achievements.
International Treaties and Cooperation About the Protection of the Stratospheric Ozone Layer
This page summarizes the history of international cooperation on the protection of the ozone layer, including: the Vienna Convention; the Montreal Protocol; past amendments to the Montreal Protocol including the Kigali Amendment on the phasing down of hydrofluorocarbons (HFCs); and the United Nations Environment Programme (UNEP)’s Ozone Secretariat.
Recent International Developments under the Montreal Protocol
Learn about recent action to address HFCs (common substitutes for ozone-depleting substances) under the Montreal Protocol.
The Multilateral Fund (MLF) was established in 1991 to assist developing countries meet their Montreal Protocol commitments. To date, the MLF has approved activities including industrial conversion, technical assistance, training, and capacity building worth over US $3.0 billion. The main objective of the MLF is to assist developing country parties whose annual ODS consumption falls below a specified threshold to comply with the control measures of the Protocol.
The UNEP Ozone Secretariat hosts a Data Access Center that reports on ODS and HFC data submitted by each country, including the United States.
Climate and Clean Air Coalition
The United States is a founding partner of the Climate and Clean Air Coalition (CCAC), a global effort focused on reducing short-lived climate pollutants across sectors. CCAC partners have supported the development of HFC inventories and studies, information exchange on policy and technical issues, demonstration projects to validate and promote climate-friendly alternatives and technologies, and capacity-building activities to disseminate information on emerging technologies and practices to transition away from high-GWP HFCs and minimize HFC leakages.