At 7am on Saturday October 15, 2016, in the Rwandan capital Kigali delegates to the Twenty-Eighth Meeting of the Parties to the Montreal Protocol burst into applause. News reports and commentators later that day were enthusiastic. ‘Kigali deal on HFCs is big step in fighting climate change’, declared the Guardian; ‘Kigali delivers second big climate deal’ announced the Indian Express; ‘October 15, 2016: the day the Earth got a little cooler’ tweeted the US Environmental Protection Agency.
What happened in Kigali? Why so much joy over an amendment to a 29-year-old treaty which took seven years to agree? And how come an agreement designed to protect the ozone layer was being used to fight climate change?