We help cities move forward and move fast
“For how many years, if not decades, have we seen C40 Cities really take the lead on very difficult issues when national governments have not been able to do – and they just continue to do it. They keep being cutting edge.”
Christiana Figueres, Outrage + Optimism podcast
For 20 years, C40 has championed cities as the catalysts for climate action.
Our mayors set the pace for climate action. They deliver results on the ground and drive change on the world stage.
The Global Urban Data Centres Pact
With data centre demand growing faster than ever, more than 40 mayors across 6 continents are stepping up to make sure that growth works for the people and places we love.
Find out how cities are leading on a sustainable, affordable digital future.
Strengthening cities to deliver
Learn how cities create the conditions for effective climate action through smarter planning, inclusive decisions, and climate-aligned budgets.
City action drives global change
Discover how C40 Cities and its mayors shape global finance, governance, and policy to scale climate action.
Change people can believe in
See how mayors build the public support, political will, and global solidarity that make ambitious action possible.
Smarter systems, stronger cities
Explore how transforming city systems helps scale up climate action and create more liveable cities.