Sustainable Urban Systems

This special issue demonstrates how practical solutions to the development of sustainable cities can be achieved through studying urban metabolism, urban ecology, city carbon and water footprints, the dynamics of city growth, and the interdependency between social actors, institutions, and biophysical system flows. than half the world’s people and about 80% of those in developed nations live in cities and urban areas. These vast urban populations consume a majority of the world’s resources, contribute to environmental degradation locally, regionally, and globally; and simultaneously are highly vulnerable to the consequent impacts of such changes (e.g., climate change). Developing environmentally sustainable cities is one of society’s grand challenges in the coming decades. Transformation of infrastructure systems is understood to be key to developing sustainable, resourceefficient cities (Boyle et al. 2010; Sahely et al. 2005). The framework for urban green growth developed by the Organisation for Economic Co-operation and Development (OECD) sees infrastructure, along with innovation and human capital, as being the starting conditions for achieving green jobs, green supply and consumption, and urban attractiveness (Hammer et al. 2011). The United Nations Environment Programme (UNEP 2012) identifies five key thematic infrastructure areas for achieving resource efficient cities—building energy efficiency, waste management, sustainable urban transport, water/wastewater, and urban ecosystem management—but stresses that it is integration between sectors and across scales that is most important. Our goal with this special issue on sustainable urban systems is to apply methods of industrial ecology toward the sustainable development of cities, their supporting hinterlands, and the networked infrastructure that connects them. The methods include familiar tools of industrial ecology, such as life cycle assessment (LCA), material flow analysis (MFA), environmental footprinting, and scenario modeling; but there is also an effort to push the interdisciplinary boundaries of in-