CHICAGO — Former President Barack Obama is expected to address a gathering of mayors from around the globe convening in Chicago to discuss climate change after President Donald Trump said the U.S. will pull out of the Paris climate accord.

Chicago officials are billing the two-day North American Climate Summit Chicago as the first of its kind in the city. Chicago Mayor Rahm Emanuel says he’s honored Obama will join the summit, which kicked off Monday evening and wraps up Tuesday.

Chicago’s Chief Sustainability Officer Chris Wheat says the idea is to “fill the void” the Trump administration has left. He says mayors will sign a charter and discuss solutions including expanding access to public transportation.

Other mayors attending include Valerie Plante of Montreal and Miguel Angel Mancera of Mexico City.