Via Planetizen News, here's an interesting sustainability ranking for 25 US cities. Now, I haven't had time to look through the methods thoroughly. But my first impression is that it gives undue weight to intentions, and not enough to actual performance.

For example, Portland does exceptionally well in climate and energy policy, while New York City's rank on energy policy is only middling. But this only measures what cities say about energy, not what they actually do. In the real world, however, the climate doesn't care about good intentions. And in point of fact--at least where transportation emissions are concerned--Portland eats The Big Apple's dust. Gotham has by far the most energy efficient and climate-friendly transportation system in the U.S., largely because higher residential densities and a good mix of residences, jobs, and services let many New Yorkers get around on public transit or on foot. So even though Portland is doing a good job of talking the talk on energy efficiency, in New York City they're (literally) walking the walk.

That's not to say that Portland's energy policy is irrelevant, or that rankings like these aren't a useful exercise. Far from it.  Still, actions speak louder than words -- and any attempt to measure sustainability should look far more closely at what cities actually do than at what their leaders say.