In the summer of 2006 a peculiar film, An Inconvenient Truth, starring the American politician Al Gore, started its successful career. In its first year it became the third most-watched documentary ever made. In the Intervention section John R. Mc Neill, one of the most important American environmental historians, focuses on the film, which he uses to broaden the discourse from the problem of the global warming of the planet the subject of the documentary film to the more general issue of American policy (in particular that of Gore) towards the environmental issue.