There have been subterranean ruminations in the comments sections of this blog regarding the recent column that urbanologist Joel Kotkin published Sunday in the Washington Post. Kotkin, as he always does, rose to the defense of the “suburbs” (a term he leaves undefined, but which presumably refers to those parts of metropolitan regions lying outside the traditional urban cores) in the context of Global Warming.
While I disagree with many of Kotkin’s conclusions, I always find him worth reading. He often raises points that force me to think through my own positions more carefully. For instance, commentators in the “smart growth” camp (or, in my case, the market-oriented sub-camp of the smart growth movement) contend that “sprawl” (by which, I presume, he refers to scattered, disconnected, low-density development) is wasteful of energy. As we remind readers endlessly in Bacon’s Rebellion, that’s because “sprawl” makes people drive greater distances and consume more gasoline.
But Kotkin responds that the world’s “cities” (by which he presumably means the high-density urban core of metro regions) are energy inefficient, too, in their own way.
Studies in cities around the world — Beijing, Rome, London, Tokyo, Los Angeles and more — have found that packed concentrations of concrete, asphalt, steel and glass can contribute to a phenomenon known as “heat islands” far more than typically low-density, tree-shaded suburban landscapes. As an October 2006 article in the New Scientist highlighted, “cities can be a couple of degrees warmer during the day and up to 6C [11 degrees Fahrenheit] warmer at night.” Recent studies out of Australia and Greece, as well as studies on U.S. cities, have also documented this difference in warming between highly concentrated central cities and their surrounding areas. …
Urban heat islands increase the need for air conditioning, which has alarming consequences for energy consumption in our cities. Since air conditioning systems themselves generate heat, this produces a vicious cycle.
This sounds totally plausible to me. And it’s definitely an argument against those who would use government coercion and social engineering to pack people into higher density environments. But I would raise two points.
First, the fact that urban centers are energy sinks does not negate the fact that sprawling suburbs energy inefficient. From an energy efficiency viewpoint, there may well be an optimum level of density between the two extremes. Kotkin points to the “village” scale of Reston as a positive example. Well, as Ed Risse frequently observes, if the one million-plus inhabitants Of Fairfax County lived in communities developed at Reston densities, two-thirds of the county would be open space today. A Reston-style Fairfax would offer the best of both worlds: fewer vehicle miles driven, without the heat-island effects of downtown Washington.
Second, no one really knows the “best” human settlement pattern. Even if we could figure it out for one point in time, the ideal would change with new technologies, shifting demographic patterns and changing energy prices. That’s why we need a decentralized, flexible system of land use based upon marketplace principles that allow individuals to optimize their own personal good. Here’s the trick: Market signals will lead us astray if they are distorted by government action at the behest of organized special interests. We need to provide a level playing field in which households and enterprises pay their location-variable costs.
There’s one more trick: Ideally, those location-variable costs should cover externalities imposed upon society such as pollution and the necessity of safeguarding Middle Eastern oil supplies. How you do that, I’m not sure. But in the abstract, that’s what we need to do.
