Many scientists and journalists are cautious in listing climate change as a causal factor behind a storm like Sandy. Understandably so: weather emerges as part of a complex system, and it would be impossible to say whether a storm would or would not have materialised without global warming. But scientists are becoming ever less shy in drawing a line between a higher frequency of "extreme" weather events and a warming climate. Climate shifts the probability distribution of such events, and so global warming may not have "caused" Sandy, but it makes Sandy-like storms more probable. As the ever-less-funny joke goes, 500-year weather events seem to pop up every one or two years these days.