Durwood Zaelke’s eye for an environmental “quick fix” has arguably saved the world half a degree Celsius of warming.

The environmental lawyer is the little-known driving force behind a key amendment to what's been called perhaps the most successful international agreement ever.

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.