C40 Cities
A global network of nearly 100 cities committed to urgent climate action.
C40 Cities - About C40C40 Cities is a global coalition of 96 cities representing one-twelfth of the world's population and one-quarter of the global economy. Founded in 2005 by 18 megacities, the organization aims to help the world limit global heating to 1.5°C and halt climate breakdown by halving fossil fuel use by 2030.
The organization operates on a performance-based membership model where cities must meet specific C40 Leadership Standards to remain in the network. Governance is managed by a Steering Committee of mayors from the Global North and Global South, with leadership including President Michael Bloomberg and Executive Director Mark Watts.
C40 supports its members through technical assistance, peer-to-peer exchange, research, and knowledge sharing. By amplifying the voice of cities to national governments, the organization seeks to create healthy, equitable, and resilient communities while halving the collective carbon emissions of its members within a decade.