Cities must address climate change. More than half of the world’s population is urban, and cities emit 75% of all carbon dioxide from energy use1. Meeting the target of the 2015 Paris climate agreement to keep warming well below 2° C above pre-industrial levels requires staying within a ‘carbon budget’ and emitting no more than around 800 gigatonnes of CO2 in total after 2017.
Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social–ecological–technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales.
To make cities better for people and the planet, the approach must become more systemic and pragmatic, and include the global south.
More than half of the world’s population now live in urban areas, and both the proportion and numbers continue to grow. In future, we will require drastically different ways of planning, building and governing cities.