Push to decarbonize cities after Paris talks

As the United Nations climate summit in Paris draws to a close, we suggest that cities should be a focus of action against climate change (see also D. G. Victor and J. P. Leape Nature 527, 439–441; 2015). Covering just 3% of Earth's surface but housing more than half of its population, they account for 70% of global energy demands.

Cities are already ahead of nations on climate policy. Initiatives such as C40 Cities (www.c40.org) and the World Mayors Council on Climate Change (go.nature.com/yyqjre) help urban centres to integrate climate objectives into current policy and long-term planning. The Cities for Climate Protection campaign run by the global cities network ICLEI, for example, has prevented emissions equivalent to some 54 million tonnes of carbon dioxide from more than 1,000 cities (see www.iclei.org).

We shall still have to cope with factors that affect city infrastructures and supply chains, such as rising sea levels, accelerating migration from rural to urban areas, and more frequent and extreme weather events. Fundamental changes are needed in the way that we build and manage the urban environment (see go.nature.com/q61pq5).