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.

Episode Producer: Ilan Goodman

A series for Radio 4 by BBC Science in Cardiff.