It was an environmental and political success story that resonates in today’s contentious debates over climate change. In the 1980s, the planet was threatened by the growth of a continent-sized hole in the ozone layer above Antarctica, a hole that scientists determined was due to the impact of human-made chemicals called chlorofluorocarbons, or CFCs, found in refrigerants and hairsprays. The ozone layer provides vital protection from the sun’s high-frequency ultraviolet rays. The alarming erosion of that layer provoked international concern and, eventually, the Montreal Protocol that led to the phasing out of CFCs. Two of the principal, and unlikely, actors in the drama were President Ronald Reagan and British Prime Minister Margaret Thatcher. Anne Gorsuch, Reagan’s EPA administrator, had told Congress that the research by F. Sherwood Rowland and Mario Molina on CFCs was highly controversial and cut the agency’s research on them. But when Lee Thomas became EPA administrator, proponents of the ban gained an advocate. Secretary of State George Shultz convinced Reagan – who was no fan of regulation – that the threat was real. Margaret Thatcher, who was trained as a chemist, appealed to world leaders to provide the money to make the Protocol work. “You’ve got to have leaders who can come to a conclusion and lead,” Shultz says in the film. The same is true for action on climate change, says chemist Mario Molina, who shared a Nobel Prize for his role in the discovery of the CFC problem. Victoria Gill, science reporter for the BBC, called the film gripping throughout. “It is rare to see a chemistry story presented in such a human way,” she said. Jamie Lochhead, writer and director of the film, said: “As climate change begins to feel like an impossible challenge, we felt that the story of how the world came together to fix the hole in the ozone layer offered a timely message of hope.”