The City Solution - Robert Kunzig via National Geographic Magazine

Can we turn the corner, and end sprawl?

Robert Kunzig via National Geographic Magazine

Sprawl is not just a Western phenomenon. By consulting satellite images, old maps, and census data, Shlomo Angel, an urban planning professor at New York University and Princeton, has tracked how 120 cities changed in shape and population density between 1990 and 2000. Even in developing countries most cities are spreading out faster than people pour into them; on average they’re getting 2 percent less dense each year. By 2030 their built-up area could triple. What’s driving the expansion? Rising incomes and cheap transportation. “When income rises, people have money to buy more space,” Angel explains. With cheap transportation, they can afford to travel longer distances from home to work.

But it matters what kind of homes they live in and what transportation they use. In the 20th century American cities were redesigned around cars—wonderful, liberating machines that also make city air unbreathable and carry suburbs beyond the horizon. Car-centered sprawl gobbles farmland, energy, and other resources. These days, planners in the U.S. want to repopulate downtowns and densify suburbs, by building walkable town centers, for instance, in the parking lots of failed malls. Urban flight, which seemed a good idea a century ago, now seems in the West like a historic wrong turn. Meanwhile in China and India, where people are still flooding into cities, car sales are booming. “It would be a lot better for the planet,” Edward Glaeser writes, if people in those countries end up “in dense cities built around the elevator, rather than in sprawling areas built around the car.”

Developing cities will inevitably expand, says Angel. Somewhere between the anarchy that prevails in many today and the utopianism that has often characterized urban planning lies a modest kind of planning that could make a big difference. It requires looking decades ahead, Angel says, and reserving land, before the city grows over it, for parks and a dense grid of public-transit corridors. It starts with looking at growing cities in a positive way—not as diseases, but as concentrations of human energy to be organized and tapped.