The World is Urban

It was big news last year when the population of the United States passed 300 million, or so it would seem from the amount of ink and air time devoted to stories about the symbolic threshold. In truth, the number meant little, for it is not necessarily how many people reside in a given area that matters but how those people live; how much land, energy and other vital resources they consume; and how equitably they distribute wealth and meet their social obligations.

Sometime this year, the world will reach a much more significant milestone: For the first time in the history of humanity, there will be more people living in cities than in rural areas. Unlike a simple numerical count of warm bodies inside national borders, that figure reflects something important about the way people live and the burden their presence places on the increasingly stressed systems that sustain them.