This paper, produced through the New Climate Economy Cities Research Programme, identifies three groups of cities that will be particularly important for the global economy and climate: Emerging Cities, Global Megacities and Mature Cities. When combined, these 468 cities are projected to contribute over 60 per cent of global GDP growth and over half of global energyrelated emissions growth between 2012 and 2030 under business as usual. Furthermore, this paper reviews the contribution of small urban areas to economic growth and carbon emissions. Finally, this paper explores the potential of the 3C model to maximise the benefits of urban growth while minimising the costs in emerging cities, global megacities and mature cities, and reviews examples of cities where elements of the model have already been implemented.
