I have little doubt that global warming is real enough. My problem is whether it is really man-made or part of a natural cycle. Geological records show that the Earth has been far hotter than this many times in the past. And I dislike the way any scientist who dares to question man-made global warming is drowned out, and automatically accused of being in the pay of the oil companies. The fact that rational debate is being stifled makes me very suspicious.

In any case, we'll all be glad of the extra carbon dioxide in the atmosphere when the supervolcano under Yellowstone National Park erupts. And that is definitely a case of when and not if.