On December 5, more than 50 mayors from cities large and small came together at the North American Climate Summit in Chicago to sign a formal agreement aimed at addressing climate change. The Chicago Climate Charter calls for mayors to achieve a percent reduction in greenhouse gas emissions that’s equal or more than outlined in the Paris agreement.

Former President Barack Obama, who signed onto the Paris Agreement in 2015, lent his support to the mayors’ actions in a speech at the summit, saying, “Obviously, we’re in an unusual time when the United States is now the only nation on Earth that does not belong to the Paris Agreement. And that’s a difficult position to defend. But the good news is that the Paris Agreement was never going to solve the climate crisis on its own. It was going to be up to all of us.”

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