by Patrick Appel

Stewart Brand sees the potential of urbanization:

Urban density allows half of humanity to live on 2.8 per cent of the land. Demographers expect developing countries to stabilise at 80 per cent urban, as nearly all developed countries have. On that basis, 80 per cent of humanity may live on 3 per cent of the land by 2050. Consider just the infrastructure efficiencies. According to a 2004 UN report: “The concentration of population and enterprises in urban areas greatly reduces the unit cost of piped water, sewers, drains, roads, electricity, garbage collection, transport, health care, and schools.” In the developed world, cities are green because they cut energy use; in the developing world, their greenness lies in how they take the pressure off rural waste.

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