C40 Report Shows Megacities Accelerating Climate Action

Mayors and top officials from more than 45 cities joined global leaders for the fifth biennial C40 Cities Climate Leadership Group (C40) Mayors Summit, hosted for the first time on the African continent, by the City of Johannesburg. In addition to releasing landmark research about the climate actions taken by cities, C40 added African cities to its membership (Dar es Salaam, Nairobi and Cape Town), launched a new programme providing on-the-ground support to cities, and made a strong statement to the global community about the role of cities in tackling climate change.

During the Summit, C40 released a landmark report, Climate Action in Megacities Volume 2.0 (CAM 2.0), developed in partnership with consultancy firm Arup. CAM 2.0 provides compelling evidence that C40 cities are taking significant actions – such as implementing rigorous energy efficiency regulations for buildings, bus rapid transit lines, or flood risk mapping – to reduce carbon emissions and climate risks.

C40 Megacities_Cairo_ss

“Mayors have real power to cut emissions and improve climate resilience, and they are taking action,” said C40 Chair, Rio de Janeiro Mayor Eduardo Paes. “C40’s networks and efforts on measurement and reporting are accelerating city-led action at a transformative scale around the world.”

“Although the African continent faces disproportionate impacts from climate change, we are no less dedicated to contributing to solutions,” said C40 Summit host, Johannesburg Executive Mayor Mpho Parks Tau. “African cities are growing at a tremendous rate and as mayors, it is our duty to ensure the long-term sustainability of our communities. That’s why African mayors are stepping up to join the C40.”

Key findings of CAM 2.0 include:

● Reported action has nearly doubled since 2011, with cities now reporting more than 8,000 climate actions currently underway.
● 41% of actions are taking place at a transformative, citywide scale.
● 98% of reporting cities say climate change presents significant risks to their populations and infrastructure.
● C40’s networks have successfully driven collaboration between cities and have led to massive scale-up of projects and programmes. For instance, there is a 500% increase in cities implementing bike-sharing schemes over just two years (6 in 2011 to 36 in 2013).
● Learning between cities is truly global. For example, the number of cities reporting BRT systems more than doubled between 2011 and 2013, with 13 forerunners in the global south and 16 successors largely in developed, western countries.

“C40’s emphasis on measurement and reporting helps cities focus resources and spread the most effective solutions – and this report shows that our efforts are bringing powerful results. By using data to show what works – and what’s possible – cities can inform the global conversation on climate change and contribute to aggressive national targets to reduce emissions,” said Michael R. Bloomberg, philanthropist, 108th Mayor of New York City and President of the C40 Board.

Sectors included in the report are Adaptation & Water, Energy Efficiency, Energy Supply, Finance and Economic Development, Sustainable Communities, Transport and Waste – the infographic below highlights the key findings in each of these sectors.


The 63 C40 Cities represent 600 million people worldwide, 5% of global greenhouse gas emissions and 21% of GDP. At the Rio+20 United Nations Conference on Sustainable Development, C40 announced that member cities’ existing actions will reduce annual greenhouse gas emissions by 248 million tonnes by 2020; and that the potential reduction could be over 1 billion tonnes by 2030.

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