Metro: I understand inadvertent ignorance; I admit to being one of its victims. But willful ignorance is another matter. We’re in the middle of an ignorance revival, and I just don’t understand what the enthusiasts get out of it. Take global warming. That it’s real is beyond dispute. The polar ice caps are melting! One-third of the summer ice in the Arctic Ocean has melted, and some scientists think the Arctic summer will be ice-free by 2013. At the South Pole, an ice bridge holding …