The C40 Cities Climate Leadership Group (C40) is a network of large and engaged cities from around the world committed to implementing meaningful and sustainable climate-related actions locally that will help address climate change globally. Our organization’s global field staff works with city governments, supported by our technical experts across a range of program areas.

The C40 was created in 2005 by former Mayor of London Ken Livingstone, and forged a partnership in 2006 with the Cities program of President Clinton’s Climate Initiative (CCI) to reduce carbon emissions and increase energy efficiency in large cities across the world.  Under the leadership of then Mayor of Toronto David Miller, who served after Mayor Livingstone as C40 Chair, the organization advanced programs and partnerships that drew international recognition for the role of cities as leaders in climate action. C40 was further strengthened in 2011 via a grant from Bloomberg Philanthropies and the full integration of the CCI Cities Program.

The current chair of the C40 is New York City Mayor Michael R. Bloomberg, who – with the support the C40 executive leadership team —  guides the work of the C40, along with the members of the C40 Steering Committee: Berlin, Hong Kong, Jakarta, Johannesburg, Los Angeles, London, New York City, Sao Paulo, Seoul and Tokyo.