Ah… the immortal words of Lee Ving, via a lot of good research presented in this article by Ed Glaeser.
The five metropolitan areas with the lowest levels of carbon emissions are all in California: San Francisco, San Jose, San Diego, Los Angeles, and Sacramento. These areas have remarkably low levels of both home heating and electricity use. There are cold places, like Rochester, that don’t air-condition much and thus use comparably little electricity. There are warm places, like Houston, that don’t heat much and thus have comparably low heating emissions. But coastal California has little of both sorts of emissions, because of its extremely temperate climate and because California’s environmentalists have battled for rules that require energy-efficient appliances, like air conditioners and water heaters, and for green sources of electricity, such as natural gas and hydropower. (Some analysts argue that this greenness is partly illusory—see “California’s Potemkin Environmentalism,” Spring 2008—but certainly, by our measures, California homes use less energy.) Also, despite the stereotypes about California highways and urban sprawl, some of these five cities, like San Francisco, have only moderate levels of transportation emissions, since their residents actually live at relatively high densities, which cuts down on driving.
In one of the charts, they measured overall carbon emissions for cities, then differentiated emissions of central city residences from the suburbs. Surprises abound.
Boston and Philadelphia are the third and fifth cities on the list. Though hotter summers and more coal make Philadelphia browner than Boston, the city-suburb differences in both areas reflect the high density and abundant public transportation in their central cities. Nashville and Atlanta, on the other hand, rank second and fourth not because their central cities are particularly green but because extensive driving makes their far-flung suburbs particularly brown.
However, even these are not without their caveats, exceptions and reasons why. So you should read the whole thing. Land use patterns and incentives that shift us toward high energy-use locales instead of green ones – those are the issues.
Plus, it beats getting fat and dying your hair.