In part because we have a political press obsessed with Washington, we tend to gauge the success of climate and energy legislation only through the national lens. And the picture from Capitol Hill is deeply depressing. One party completely ignores the science of climate change and only wants to engage on fossil fuels, and that doesn’t exactly leave a lot of room for the other party—although the Democrats have their own divisions on climate and energy. The result—as we’ve written over and over again—is gridlock.

But U.S. cities aren’t waiting around for Congress—which is a good thing, considering 82% of Americans now live in cities, a percentage expected to hit 90% by 2050. “The best cities really have comprehensive plans for climate change and population growth across all categories,” says Eric Spiegel, CEO of Siemens USA. “U.S. cities aren’t waiting for Washington.” At the Aspen Ideas Festival today Siemens and the Economist Intelligence Unit released a ranking of the greenest cities in the U.S. and Canada. Some of the findings:

The greenest city in North America is—not surprisingly—San Francisco, in part because Frisco recycles 72% of its waste, tops in the country.

Number two is Vancouver, which has managed to slash its carbon emissions over the past decade.

New York—which benefits from its extreme density—has adopted a plant to care for 1 million trees throughout the five boroughs.

Check out the full index here. Some of the findings aren’t too surprising. The U.S. has been very successful in reducing air pollution over time—as any long-time resident of Los Angeles could tell you—but American cities are not great with public transit. A wealthier city is more likely to be a sustainable one—hence cities like New York and San Francisco, with expensive downtowns. But wealth isn’t the only factor: Canadian cities do surprisingly well even though they have a per-capita GDP that is $7,000 lower than American cities on average. The difference often boils down to leadership, with powerful mayors like New York’s Michael Bloomberg—whatever you think of him—able to keep their cities focused on sustainability for the long-term. “The mayors we talk to sound more like CEOs than politicians, because they’re focused on the bottom line,” says Siegel. “For them, sustainability means business.” Their peers in Washington could take a lesson.