The ranks of America’s “climate sceptics” have been growing quietly for some months now. And at the weekend a watershed was reached: the usually left-wing New York Times put the British-born physicist Freeman Dyson on the front of its Sunday magazine. “All the fuss about global warming is grossly exaggerated,” is how Professor Dyson puts it. Out in the blogotwittersphere, the Greens can hardly believe that the same media that once helped Mr Gore to win both an Oscar and a Nobel prize are now promoting such heresy. To make matters more infuriating, Professor Dyson isn’t even a conservative: he’s a left-wing, Obama-voting, peace-marching, boho-academic genius who argues that coal-produced electricity has liberated millions in China from poverty, and that “greens are people who’ve never had to worry about grocery bills”.