Climate change is a global problem — but as of yet, there’s no global solution. That’s why mayors across the U.S. are taking action, from building green to organizing bike rides, from redeveloping downtowns to cutting emissions. Here are just a few of the municipal leaders who have worked to take our collective future into their own hands.

Michael BloombergBloomberg unveils his grand Plan.PlanNYC 20301. Michael Bloomberg, New York City.
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Call New York the accidental eco-city: cram millions of people onto an island, and you’ve got to figure out how to build up, not out. Throw a big park in the middle, and voila: you’ve got an anti-sprawl city that values open space. During his tenure, Bloomberg has made the most of that happy accident, creating an ambitious 127-point initiative called PlanNYC 2030 that encompasses everything from reclaiming waterfronts to repairing electrical grids to reducing traffic congestion. (OK, that last one hasn’t gone so well.) A year after unveiling the plan in 2007, the city had launched a full 93 percent of its components.