GREEN
04/10/2009 05:12 am ET | Updated May 25, 2011

City Living Is Green: Why The Lorax Was Wrong

Economist Edward L. Glaeser penned a guest blog for the New York Times about green city living. He points out that people who want a much smaller carbon footprint should live in high-density cities, where travel is less necessary and living quarters are more confined.

In almost every metropolitan area, we found the central city residents emitted less carbon than the suburban counterparts. In New York and San Francisco, the average urban family emits more than two tons less carbon annually because it drives less. In Nashville, the city-suburb carbon gap due to driving is more than three tons. After all, density is the defining characteristic of cities. All that closeness means that people need to travel shorter distances, and that shows up clearly in the data.

While public transportation certainly uses much less energy, per rider, than driving, large carbon reductions are possible without any switch to buses or rails. Higher-density suburban areas, which are still entirely car-dependent, still involve a lot less travel than the really sprawling places. This fact offers some hope for greens eager to reduce carbon emissions, since it is a lot easier to imagine Americans driving shorter distances than giving up their cars.

Glaeser refers both in that piece and in a piece her wrote for the City Journal recently to an amusing (but true) parable about the environment:

On a pleasant April day in 1844, Henry David Thoreau--the patron saint of American environmentalism--went for a walk along the Concord River in Massachusetts. With a friend, he built a fire in a pine stump near Fair Haven Pond, apparently to cook a chowder. Unfortunately, there hadn't been much rain lately, the fire soon spread to the surrounding grass, and in the end, over 300 acres of prime woodland burned. Thoreau steadily denied any wrongdoing. "I have set fire to the forest, but I have done no wrong therein, and now it is as if the lightning had done it," he later wrote. The other residents of Concord were less forgiving, taking a reasonably dim view of even inadvertent arson. "It is to be hoped that this unfortunate result of sheer carelessness, will be borne in mind by those who may visit the woods in future for recreation," the Concord Freeman opined.

Thoreau's accident illustrates a point that is both paradoxical and generally true: if you want to be good to the environment, stay away from it.

Freak chowder-related accidents aside, Glaeser's research for the City Journal piece demonstrates that city living can require a fraction of the energy that suburban living does -- and that temperate cities require less energy than hot cities. Sort of startling, though, is that Los Angeles, a city famous for its driving culture, falls into the lowest-emitting group.