In our understanding, important areas for future scientific investigation are: Improving the understanding of resource use governance for integrated economic- environmental policies at different scales. • Improving our understanding of the func- tional linkages and trade-offs between ma- terial, energy, water, and land use. • Linking these dimensions of the societal metabolism to economic models in order to be able to run socio-metabolic scenarios for the future. • Strengthening and harmonizing metabolic analysis and models beyond the national scale. An urban metabolic perspective is especially important here. 8 Today almost 50% of the world population is urban (United Nations 2008), while 70% of the world’s energy is consumed in urban areas (Global Energy Assessment 2008). Accord- ing to UN projections, the urban popu- lation will continue to rise, while the ru- ral population will stagnate in the medium term. This means the metabolic future of our planet will be determined by the urban metabolism. • Understanding the stocks and flows dynam- ics of the material system, at different scales and for different materials. Most important here is to investigate and quantify the role of infrastructures and urban form in deter- miningfuturemetabolicflowsandthelimits to substitution. • Agreeing on a harmonized approach for assessing dematerialization. Because inter- national trade has been the most rapidly growing component of resource use, de- materialization measures need to incorpo- rate indirect (embodied) flows to capture the primary resources and emissions arising from a country’s consumption pattern. • Focusing on strategic materials and their supply-demand chains as well as their re- gional economic, social and environmental impacts.