Deprived parts of cities often lack trees and other green spaces. Residents in almost every city affected by climate change are calling for more equity and fairness, said David Miller, North American director of C40 and a former mayor of Toronto.

“Often that’s about economic goods, but it’s also about social goods like green spaces, and forests and health,” he said.

New York city is planting 1 million trees, and mapping where those are most needed, especially in deprived areas, he added. It is not just large cities that need to grow more, Mantua’s mayor said.The small north Italian city hosting the international forum is home to 50,000 people and 16,000 trees. The city council plans to increase this to 25,000 trees by 2020, to help protect it from floods and rising temperatures.

“We believe it’s not about the size of the city – climate change is everywhere,” Mattia Palazzi told the Thomson Reuters Foundation.

Mantua, voted Italy’s greenest city two years in a row, is in one of the most polluted areas in Europe and needs trees to help clean the air, he said.

“Green areas create happiness … and are important for the city’s future sustainability,” he said.