In an exceprt from his new book, Walkable City: How Downtown Can Save America, One Step at a Time, Jeff Speck addresses the connection between density, walkability, and greenhouse gas emissions.
"It turns out that trading all of your incandescent lightbulbs for energy savers conserves as much carbon per year as living in a walkable neighborhood does each week," observes Speck. "Why, then, is the vast majority of our national conversation on sustainability about the former and not the latter?"
"Places should be judged not by how much carbon they emit, but by how much carbon they cause us to emit. There are only so many people in the United States at any given time, and they can be encouraged to live where they have the smallest environmental footprint. That place turns out to be the city - the denser the better."
"Quality of life - which includes both health and wealth - may not be a function of our ecological footprint, but the two are deeply interrelated. To wit, if we pollute so much because we are throwing away our time, money, and lives on the highway, then both problems would seem to share a single solution, and that solution is to make our cities more walkable. Doing so is not easy, but it can be done, it has been done, and indeed it is being done in more than a few places at this very moment."