In 1998, the climate scientist Michael Mann published a simple graph shaped like an ice hockey stick: a long straight line which curves suddenly upward at the end. It was based on decades of intrepid work by scientists around the world. But the line held a stark warning. For Michael, notoriety, abuse and a global battle over the reality of climate change followed. Hannah Fry tells the remarkable story of the people behind the hockey stick: the scientists who scaled mountains and braved oceans in search of evidence, and the dramatic fallout when the world saw what they had found.

Episode Producer: Ilan GoodmanSound Design: Jon Nicholls Story Editor: John Yorke

A series for Radio 4 by BBC Science in Cardiff.