Go Green, Go Urban

A lot of people are talking up green initiatives, but one of the most effective ways to go green is also one of the simplest to understand: encourage more activity to take place in dense, walkable cities.

* If you move from the suburbs to the city, your family's carbon footprint and energy consumption go way down, as you do more of your trips by foot and transit rather than auto. (Plus your apartment or row house is likely to be more energy efficient on account of having less exposed surfaces than the typical stand-alone house in the burbs.)

* Concentrating 2000 office jobs in a tower in the middle of downtown rather than having it be spread out over multiple locations across a metropolitan region drastically reduces auto commutes and utilities bills.

* Duke (16,000 students and faculty) has 26,000 parking spaces on campus; Penn (24,000 students and faculty) has 5,000. (This fun fact is courtesy of Penn's sustainability chief, Dan Garofalo.) You do the math in terms of the effect of that difference in car trips and impervious surfaces.

I'm not nay-saying different incentive programs by federal, state, and local governments to go green. While some will lead to colossal inefficiencies in resource allocation and grossly unintended consequences, some will be powerfully effective in stimulating the right kind of behavior, both from an economic and environmental standpoint.

But let's also remember that individual, corporate, and government decisions that lead to more people living, working, playing, and congregating in dense, walkable cities may have the greenest impacts of them all. Hey, it may be more sexy and politically correct to offer rebates for solar panels than to push for more skyscrapers downtown or make the numbers work for developers to build new housing units within city limits; but that doesn't mean it's more green.