Without the Montreal Protocol to phase out ozone-depleting chemicals, the world could have been extra 2.5℃ hotter by the end of the century.

Modeling by climate scientists found that the 1987 Montreal protocol curbing chlorofluorocarbons (CFCs) gave humans a fighting chance of limiting global heating to 1.5C as set out by the Paris agreement.

CFCs, which were once commonly used in insulation foams and aerosols, not only deplete the ozone layer but are also powerful greenhouse gases. The atmosphere has already warmed 1.1C to 1.2C above pre-industrial levels, meaning the Earth could have been facing 3.5C of warming if CFCs were still in use.