Durwood Zaelke’s eye for an environmental “quick fix” has arguably saved the world half a degree Celsius of warming.
The former environmental lawyer is the little-known driving force behind what’s been called the most successful climate treaty ever, the Montreal Protocol.
The BBC’s Hannah Long-Higgins meets him and finds that there are deeply personal reasons driving him.
Produced by the BBC’s Franz Strasser and Stephen Hounslow.
Climate Defenders is a five-part series highlighting people who lead the battle to protect the planet from rising temperatures.