He was one of the first scientists to provide evidence of the link between greenhouse gases and global warming. That was in 1987. Since then, Jean Jouzel has not stopped fighting against the climate sceptics and urging politicians to commit to the climate. Above all, for more than thirty years, he has encouraged us to change our habits and to take care of our planet to avoid the worst. Between an intimate story and a historical epic, from Janzé in Brittany to Washington via Paris and Tokyo, Jean Jouzel, in the battle of the century is a film about a man and his era, an era that has seen us become aware of the need to change our relationship with the world.