Bruce Melton, who writes regularly for The Rag Blog on issues of climate change, explains why recent occurrences of especially cold winter weather in no way contradict scientific theories about global warming. “On a warmer planet,” he tells us, “winter weather becomes more volatile. The extremes get more extreme.” In fact, some scientists now say that the chance of having extreme winter weather has increased by a factor of three, due to “feedbacks” from Arctic warming and icemelt.