Research Issues in Sustainable Consumption: Toward an Analytical Framework for Materials and the Environment VALERIE M. THOMAS* Princeton Environmental Institute, Guyot Hall, Princeton University, Princeton, New Jersey 08544 T. E. GRAEDEL Yale School of Forestry and Environmental Studies, 205 Prospect Street, New Haven, Connecticut 06511 We define key research questions as a stimulus to research in the area of industrial ecology. The first group of questions addresses analytical support for green engineering and environmental policy. They relate to (i) tools for green engineering, (ii) improvements in life cycle assessment, (iii) aggregation of environmental impacts, and (iv) effectiveness of a range of innovative policy approaches. The second group of questions addresses the dynamics of technology, economics, and environmental impacts. They relate to (v) the environmental impacts of material and energy consumption, (vi) the potential for material efficiency, (vii) the relation of technological and economic development to changes in consumption patterns, and (viii) the potential for technology to overcome environmental impacts and constraints. Altogether, the questions create an intellectual agenda for industrial ecology and integrate the technological and social aspects of sustainability. Introduction Sustainabilityhas been widelyendorsed as the over-arching goal of environmental policy. The hope sor vision sis that a strong, just, and wealthy society can be consistent with a clean environment, healthy ecosystems, and a beautiful planet. There has, however, been considerable doubt ex- pressed about the potential for scientific research in this area. We argue that many key issues of sustainability can be expressed as tractable research questions that build on existing research. We develop a part ofthat research agenda here, drawing on the results ofan NSF-sponsored workshop (1). Although research in sustainability is inherently broad and multi-faceted, it falls naturally into three basic areas: use of materials and energy, land use, and human develop- ment. These three areas are inter-related, and in various contexts two or perhaps all three might be considered together (2). For the purpose of developing a clear and manageable research agenda, we focus here on one of the three areas suse of materials and energy. Research in this area, broadly termed industrial ecology (3-5), aims to understand howthe environmentalimpactsofindustrialized systems sincluding energy and transportation, consumer products, cities, and food production scan be understood, managed, and reduced over the long term. We will not enter here into the often contentious discussion of the exact meaning of or prospects for sustainability (6-8). Rather, we focus on reducing the environmental impacts of materials and energy use as a necessary component of sustainability and on the overall goal of developing an environmentally benign technological basis for contemporary and future societies (9, 10). We divide the discussion of industrial ecology into two broad categoriesofresearch: engineered systemsand global systems. In the area of engineered systems, the underlying issues involve reducing the environmental impacts of products while simultaneously minimizing the costs of so doing. The relevant research relates to materials, products, or product categories, with the time scale of application typically a decade or less. In the category of global systems, the underlying issue is the long-term relationship between technological development, social and economic develop- ment, and the environment. We include in this category not onlygeographicallyglobalenvironmentalproblems such as climate change and stratospheric ozone depletion but also overallhuman health and welfare, the state ofthe economy, and resource availability. In developingthis research agenda,we have tried to select and define the issues as tractable research questions for which good progress can be expected over a 1-2-decade time frame. In our judgment, engineered systems research is relatively well-advanced in the areas of life cycle assessment and analysis of strategies for environmental management. The global systems research is at a less mature stage. As with other fields of science and engineering, the development of a theoreticaland analyticalframeworkforthe use ofmaterials and energyand the resultingimplicationsforthe environment will be a continuing process. Within these two areas, we have defined a few key questions that we think will stimulate research in this field. These are listed in Table 1 and discussed below. Engineered Systems Research to reduce the environmentalimpactsofengineered systems spans a wide range of topics, disciplines, and levels of focus. As with all engineering design approaches, green engineeringwillalways be a workin progress.New materials, new analytical capacity, and new product concepts will require appropriate responses from the engineering com- munity. Here we discuss two aspects of research in this area that improve the overallbasisforre-engineeringofproducts, processes, and technological systems: (a) analysis of the environmentalimpacts ofproducts and the potentialfor re- design of products and material management and (b) environmental management strategies. Analytical Support for Green Engineering. To make processes,products,and materialmanagement more efficient and environmentally benign requires extensive redesign on a process-by-process and product-by-product basis (11- 13). Much of this work is carried out by industry, although nationallaboratoriesand university-based research also play criticalroles.In the case ofrefrigerators,for example,research at national laboratories, funded primarily by the U.S. Department of Energy, has made possible a two-thirds reduction in average energy consumption over the past 25 yr (14). For refrigerators, the design goal was clear: refrigerators require a significant fraction of household electricity, and the environmental impacts of energy use are relatively well understood. But for other kinds of products and impacts, *Corresponding author e-mail: vmthomas@princeton.edu; tele- phone: (609)258-4665, fax: (609)258-1716. Environ. Sci. Technol. 2003, 37, 5383-5388 10.1021/es034475c CCC: $25.00  2003 American Chemical Society VOL. 37, NO. 23, 2003 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 5383 Published on Web 10/24/2003