Our Partners & Funders

C40 partnerships
Former President Bill Clinton joins Former Mayor Michael Bloomberg to announce the merger between C40 Cities Climate Leadership Group and the Clinton Climate Initiative into one organization. (Edward Reed / NYC Mayor Office)

Partnerships Designed for Solutions

C40’s partners and funders understand the relationship between cities and climate change and are committed to advancing urban leadership in driving solutions.

Network Partner, Clinton Climate Initiative, Clinton Foundation

Clinton Climate Initiative, Clinton Foundation


C40 works in an aligned partnership with the Clinton Climate Initiative (CCI) Cities program, which was started by the Clinton Foundation.

Network Partner, Bloomberg Philanthropies

Bloomberg Philanthropies


C40 was strengthened in 2011 by a strategic and multi-year grant from Bloomberg Philanthropies, which helped to forge the closer alliance with the CCI Cities Program and position the combined effort as one of the preeminent climate action organisations in the world.

Network Partner, Children's Investment Fund Foundation (CIFF)

Children's Investment Fund Foundation (CIFF)


The Children's Investment Fund Foundation (CIFF) is an independent, philanthropic organisation. Our staff and Trustees combine the best of business and the best of development, bringing a wealth of experience from both sectors to CIFF's work. We aim to demonstrably improve the lives of children in developing countries by achieving large-scale, sustainable impact. We believe that every child deserves to survive, thrive and mature into adulthood in a supportive and safe environment. However, climate change disproportionately affects children living in poverty in developing countries. A key focus for CIFF is climate-smart urbanisation.

Network Partner, Realdania



Realdania is a modern philanthropic association that works to create quality of life and benefit the common good by improving the built environment: cities, buildings and the built heritage. Realdania grew out of a 150 year old mortgage credit association whose credit activities were sold off in 2000. Over the past 13 years Realdania has engaged in a total project value of approximately EUR 3.7 billion. Realdanias grants accounted for EUR 1.9 billion.

Network Partner, Arup



Arup is an independent professional services consortium that delivers innovative and sustainable solutions in a broad range of disciplines. In 2010, C40 partnered with Arup to deliver a series of workshops named C40 Urban Life, tailored to individual city’s needs. Using its “Sustainable Integrated Development” approach — which addresses the interdependency of land use, energy, waste, water, transport, agriculture, buildings, economics and sociology — Arup delivered action orientated Urban Life workshops aimed at developing individual city's carbon reduction programmes. In 2011, C40 partnered with Arup to create the Climate Action in Megacities Report, a comprehensive analysis of what the mayors of the C40 megacities are doing to tackle climate change.

Network Partner, ICLEI



In June 2011, C40 partnered with ICLEI — Local Governments for Sustainability. This partnership will establish a global standard for accounting and reporting community-scale greenhouse gas emissions that can be used across multiple platforms. It can help local governments accelerate their emission reduction activities, whilst meeting the reporting requirements of climate financing and national monitoring entities.

Network Partner, CDP



C40 began partnering with CDP (formerly The Carbon Disclosure Project) in June 2011 to bring self-reported data from the world’s largest cities into a comprehensive report on cities’ greenhouse gas emissions and climate risk data. Today, the collaboration includes C40-specific open data portals, premised on the belief that better, more transparent measurement leads to better management. With the right processes in place in partnership with CDP, cities can share strategic insights and reduce their exposure to climate risks and impacts. 

Network Partner, Siemens


Partner Funder

In April 2013, the C40 Cities Climate Leadership Group (C40) and Siemens announced a new collaboration, which includes a global awards competition to recognize innovative city driven climate actions. The partnership also will make Siemens’ technical expertise directly available to C40’s robust network of cities, enhancing the ability of both organizations to help cities accelerate their climate action efforts. The newly created “City Climate Leadership Awards” provides recognition for cities that are demonstrating leadership through the implementation of scalable solutions that lower emissions and address issues cities are facing as a result of global climate change. In addition to the City Climate Leadership Awards, Siemens supports the C40 Measurement and Planning Initiative, which is an effort dedicated to enhancing each member city’s ability to measure data, take action and track progress towards self-identified goals.

Network Partner, World Bank

World Bank


In 2011, C40 partnered with the World Bank in an agreement announced during the C40 Mayor’s Summit in Sao Paulo. This agreement will strengthen cooperation between the two organisations by establishing a consistent approach to cities’ climate action plans and greenhouse gas emissions measurement and reporting. Common international metrics will help to better track progress against targets. Equally important, metrics will facilitate cities' access topublic and private sources of capital for climate mitigation and adaptation projects. The World Bank offers a single entry point for C40 cities to access World Bank climate change-related capacity building and technical assistance programs, and climate finance initiatives. This ‘one window’ access helps city governments understand what World Bank resources exist and how to tap into them.

Network Partner, Thoughtbot


Expert designers and developers who turned C40's idea into the right website application. Thoughtbot supports the work of C40 to reduce greenhouse gas emissions and increase the resiliency of cities worldwide.