Who we are

C40 is a global network of nearly 100 mayors of the world’s leading cities that are united in action to confront the climate crisis.

Mayors of C40 cities are committed to using an inclusive, science-based and collaborative approach to cut their fair share of emissions in half by 2030, help the world limit global heating to 1.5°C, and build healthy, equitable and resilient communities. C40 supports mayors to do this by:

Our cities

Cities in the C40 network earn their membership through action.

Our Leadership Standards set the minimum requirements for all member cities and safeguard the integrity of C40 as a network of climate leaders.

Membership operates on performance-based requirements, not on fees, and every city in the C40 network is reviewed annually against our Leadership Standards.

C40 Leadership Standards 2021–2024:
  1. Plan. City has adopted a resilient and inclusive climate action plan aligned with the 1.5˚C ambition of the Paris Agreement, and updates it regularly;
  2. Deliver. In 2024, city remains on track to deliver its climate action plan, contributing to increased resilience, equitable outcomes and halving C40’s overall emissions by 2030;
  3. Mainstream. City uses the necessary financial, regulatory and other tools at their disposal to address the climate crisis and mainstreams their equitable climate targets into the most impactful city decision-making processes;
  4. Innovate. City innovates and starts taking inclusive and resilient action to address emissions beyond the direct control of the city government, such as associated with goods and services consumed in their city;
  5. Lead. Mayor and the city demonstrate global climate leadership and inspire others to act in support of the Paris Agreement.

C40 mayors have been at the forefront of climate leadership for over 15 years, driving the conversation around climate action and environmental justice to place these issues front and centre in our local policies and on the international agenda.

Our principles

C40 is committed to being an equitable, diverse and inclusive organisation.

Not only in the way we recruit, manage and develop our international workforce, but also in the manner in which we work with C40’s nearly 100 member cities worldwide. 

To succeed in our mission of helping the world limit global heating to 1.5°C and building healthy, equitable and resilient communities, we are working to deliver a future where everyone, everywhere, can thrive.

This vision can only be achieved with a diverse workforce and an inclusive mission.

C40 Annual Reports

Access more:
C40 Annual Report 2019
C40 Annual Report 2017