Your article about the ever-faster growth of the world’s urban population focuses on the ever-faster growth of natural disasters affecting cities (“Some Hard Talk about Towns.” October 6, 2007), but you do not even attempt explaining the latter phenomenon. Whence the increase in the number of natural disasters, let alone the acceleration in that increase? The only possible explanation of this phenomenon is climate change, which you mention in passing only in the context of coastal cities. Of course, floods, mudslides, and landslides can occur far from the coast, as well. By your own evidence, climate change must also be increasing at an increasing rate. The fact that the world’s urban population is increasing at an ever-faster rate thus points at the ever-greater peril that climate change entails. And this is entirely missing from your article.