Montreal Protocol

The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of ozone-depleting chemicals such as chlorofluorocarbons and halons. It followed the discovery of the Antarctic ozone hole by British Antarctic Survey scientists in 1985 and the Vienna Convention of the same year. It entered into force in 1989 and has been amended several times to speed up the phase-out and cover more substances. It was eventually ratified by every member of the United Nations. The protocol is widely regarded as one of the most successful environmental agreements, and scientists expect the ozone layer to recover to its 1980 levels around the middle of this century. The Kigali Amendment of 2016 added hydrofluorocarbons, which are powerful greenhouse gases.

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