Cities push for full partnership at COP30
10-21 November 2025, Belém
At COP30, C40 mayors demonstrate what climate action delivers when cities have the power and resources to act. Through their Yearly Offers of Action, cities are showing the concrete progress being made to protect the people and places we love.
With the right support from national governments, cities can go even further and faster. This year, mayors are calling for cities to be recognised as full partners in climate decision-making, with the finance and collaboration needed to turn ambition into results.
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.
We help cities move forward and move fast
Our 97 cities represent nearly a quarter of the global economy. Together, we design, test, and improve solutions that raise the standard for everyone.
Action needs infrastructure
Explore how cities are building the foundations that raise climate ambition and strengthen their capacity to deliver action.
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.