C40 Cities, Climate Action in Megacities 2.0

  • C40 and Arup collected 1.7 million unique data points from cities – one of the largest datasets developed on city action.
  • The analysis of this rich dataset shows that actions taken by C40 Cities tackling climate change have almost doubled since 2011.
  • Mayors of the world’s major cities are taking concrete actions that demonstrate that preventing catastrophic climate change is possible.

Arup and C40 cities have delivered a major new opportunities and baseline report which shows a clear trend of expanding climate action in cities.

Climate Action in Megacities 2.0 (CAM 2.0) is based on a comprehensive survey, led by Arup, of some 59 C40 member cities around the world including Rio de Janeiro, New York, London, and Hong Kong.

Arup designed and analysed one of the largest datasets developed on city action, in collaboration with C40 Cities. The research recorded 8,068 climate actions amongst C40 cities, almost double that recorded in 2011’s baseline report. The mix of activities ranges from public cycle hire schemes and renewable energy initiatives to extending mass transit metro lines and replacing high energy street lighting with LED bulbs.

The report proves that what happens in C40 cities matters to the whole world. With a lack of tangible outcomes from inter-governmental efforts to reduce greenhouse gas emissions, it is increasingly significant that mayors of the world’s megacities are taking concrete actions that demonstrate that preventing catastrophic climate change is possible. The analysis shows a clear pattern of mayors acting most where they have strong powers, but also innovating where they do not.

The research is particularly important because it quantifies what is being done and identifies what works. This allows city leaders and technical specialists to learn lessons from other areas before they embark on a new initiative. By helping city authorities to understand how other cities have successfully tackled shared challenges, cities worldwide can build a roadmap to take suitable actions that make a meaningful difference.

 “The report demonstrates – unequivocally – that cities have the power, the expertise, the political will and the resourcefulness to continue to take meaningful climate action. More than ever before, they are at the forefront of the issue of climate change as leaders, innovators and practitioners.”

— President of the C40 Board, 108th Mayor of New York City, Michael R. Bloomberg

The Climate Action in Megacities 2.0 report is now available to view.


  • An image of a Melbourne Street with pedestrians and a cyclist crossing over. © Noah Sheldon/Julian Richards.Open gallery

    49 per cent of reported actions taken by C40 cities are to promote walking and cycling – more than any other action area in private transport.