World leaders gathered at the United Nations General Assembly yesterday for a climate change summit, but it may be city leaders who actually get something done.

As large nations like the U.S. and China continue to refuse drastic action on climate change, a special envoy of mayors hopes to make a global impact by attacking the problem at the local level. The Compact of Mayors is an initiative put together by U.N. Secretary-General Ban Ki-moon and former Mayor Michael Bloomberg. According to Scientific American, 69 cities have jumped on board so far. Mayors from each city presented their specific plans to combat carbon emissions.

Mayor Bill de Blasio spoke at the U.N. summit yesterday and reiterated his commitment to making New York a more sustainable city. The plan is to cut greenhouse gases by 80%, with a self-imposed 2050 deadline. Because 75% of New York’s emissions come from new construction, de Blasio plans to reach his goal by refurbishing old buildings and making them more energy efficient.

As Eduardo Paes, Mayor of Rio de Janeiro, puts it, “Nations are not delivering, how can there be any argument against prioritizing cities?” De Blasio concurred, saying, “The failure to reach (our) goal dooms us all. If we don’t get it right now, at some point it will be too late.” Since more than half of the world’s 7.2 billion people now live in cities, a local approach is sensible, to say the least.

Though he no longer runs a city, Bloomberg is using his massive network and bank account to push the initiative forward and rally organizations like World Bank and WWF to support the cause. And since he isn’t mayor anymore, he doesn’t have to fly to Bermuda every weekend in his private jet. Score one for Mother Earth. (Photo: Public Advocate Bill de Blasio/Flickr)