C40 Cities Annual Report

The C40 Cities Annual Report 2024 presents the collective climate‑action achievements of nearly 100 major cities worldwide. C40 Cities, a network coordinated by mayors and supported by organisations such as Bloomberg Philanthropies, the Children’s Investment Fund Foundation and Realdania, publishes the report to showcase progress toward the 1.5 °C target and to document high‑impact initiatives across sectors including energy, transport, waste, and housing. The report is authored by Sadiq Khan (Mayor of London), Yvonne Aki‑Sawyerr (Mayor of Freetown) and Mark Watts (Executive Director of C40).

C40’s Leadership Standards require member cities to develop science‑based climate action plans, integrate climate budgeting, and demonstrate measurable emissions reductions. By the end of 2024 the network counted 92 cities with fully compliant plans, representing ≈ 920 million people and ≈ 23 % of global GDP. Three‑quarters of C40 cities are already reducing per‑capita emissions faster than their national governments, contributing to a 7.5 % decline in city‑wide emissions since 2015, compared with a 1.5 % global decline.

The report documents 1 ,200 high‑impact actions, 1 ,172 of which are in implementation. Key accelerators include Clean Air, Clean Construction, Renewable Energy, and Good Food Cities. C40 cities have collectively avoided ≈ 3.2 billion tCO₂e by 2050 through these actions, equivalent to the total emissions of the 27 EU member states. Examples include London’s £100 million clean‑air fund, New York’s US $200 million coastal‑resilience project, and Rio de Janeiro’s US $24 million Power Purchase Agreement for municipal buildings.

Housing‑related climate work is a central focus. London’s Clean Construction Accelerator supports prefabricated, low‑carbon building methods, aiming for 60 % prefabricated new builds by 2025. New York’s climate‑budgeting approach links housing retrofits to emissions cuts, while Mumbai’s first city‑wide climate budget targets energy‑efficient public housing. C40 cities report that ≈ 400 city officials from 20 cities have completed the Clean Construction e‑learning course, fostering green‑building expertise across the network.

In 2024 C40 mobilised US $75.6 million in total income, with 70 % of expenditure directed to support Global South cities. Funding sources span philanthropy, government, and corporate partners such as Google, IBM, and Uber. The C40 Cities Finance Facility, co‑implemented with Germany’s GIZ and funded by the UK FCDO, German BMZ, and French AFD, underpins many large‑scale infrastructure and housing projects.

• 92 C40 cities have climate‑action plans aligned with a 1.5 °C pathway.
• 1 ,200 high‑impact actions delivered, ≈ 1 ,172 in progress.
• Emissions in C40 cities fell 7.5 % since 2015, outpacing the global average.
• Clean Construction accelerator targets 60 % prefabricated new builds in London by 2025.
• Funding > US $75 million in 2024, with 70 % supporting Global South initiatives.
• Over 400 city officials trained in sustainable building practices.

The report demonstrates that coordinated city networks can accelerate low‑carbon housing through policy‑driven standards, dedicated financing mechanisms, and knowledge‑sharing platforms. European cities can draw on C40’s examples—such as prefabricated construction, climate‑budget integration, and public‑private financing—to scale up retrofitting programmes, achieve net‑zero building targets, and create green jobs. The documented emissions reductions and financial commitments provide a benchmark for European municipalities aiming to meet the EU’s 2030 and 2050 climate objectives while delivering affordable, resilient housing.