C40 Cities
C40 has 96 member cities. Making up more than 20% of the global economy1. December 19, 2023. C40 Co-Chairs Mayor Aki-Sawyerr and Mayor Khan react to COP28 final agreement. More News & Insights. C40 Cities is a global network of nearly 100 mayors of the world's leading cities that are united in action to confront the climate crisis.