This is a comprehensive analysis of actions underway in the world’s megacities to address climate change. It not only underscores what cities have done to date, but also what they can do now and in the future as local leaders, and as a collective, to have a significant global impact.

The 58 cities now represented within the C40 account for 8 percent of the global population, 12 percent of global greenhouse gas emissions and 21 percent of global GDP. Our cities control significant economic, environmental and social assets – and have enormous potential to set the framework for a low carbon economy. To date, however, there has been no attempt to measure the true impact of local action, or to capture the value of the C40 network. The C40 commissioned Arup to co-author this report as the first-ever comprehensive analysis of actions underway in the world’s megacities to address climate change. This baseline clearly illustrates the notion that “Cities Act.” To date, there are 4,734 actions currently in effect and another 1,465 under consideration.