Urban centers: An assessment of sustainability

As increasing proportions of the world's population, production, and consumption become concentrated in urban areas, the need for urban development patterns that are more ecologically sustainable becomes obvious. A large proportion of the world's urban population also has needs that are unmet. We review the scale and nature of urban change worldwide, the environmental impacts of these changes, and the potentials and the difficulties in better meeting sustainable development goals in urban centers. The discussion of the interaction between city-based production and consumption and the resources and sinks on which these rely that are outside city boundaries is a reminder that the goal is not sustainable cities but cities that contribute to sustainable development within their boundaries, in the region around them, and globally.