Marian Chertow

Marian Chertow

Manufacturer’s Association Professor of Industrial Ecology; Director of the Center for Industrial Ecology

Dr. Marian Chertow is the Manufacturer’s Association Professor of Industrial Ecology at Yale University. She is also Director of the Center for Industrial Ecology at the Yale School of the Environment. She has an appointment at the School of Management (SOM) and for 20 years taught at the National University of Singapore (NUS) having been on the founding faculty that developed the school’s Master’s of Environmental Management program. Dr. Chertow’s research and teaching focus on industrial ecology, business/environment issues, circular economy and waste management. She is best known for championing the study of industrial symbiosis involving geographically-based exchanges of materials, energy, water and by-products within networks of businesses globally. Prior to Yale, Professor Chertow spent ten years in environmental business and state and local government including service as president of a bonding authority that built a billion dollars’ worth of waste infrastructure. Her work has brought her several awards including from the U.S. EPA, the CT Women’s Hall of Fame, and the highest award from the International Society for Industrial Ecology (ISIE).

Dr. Chertow is a frequent international lecturer, is an Advisor to the Center for Energy Efficiency and Sustainability at Trane Technologies, Inc, is on the Board of TerraCycle US Inc, and the Board of the Alliance for Research in Corporate Sustainability (ARCS).

In addition to her academic work, Professor Chertow started a theatre company at Barnard College dedicated to performing Ancient Greek plays in the original language. Currently, she is teaching a cross-listed class: “Green Stages: Environmental Themes in the Theatre.” She is most proud of her husband Matthew Nemerson, SOM 1981 and daughters Elana and Joy Nemerson.

Understanding the impact of industry on the environment and seeking forward-looking means of achieving sustainable industrial development constitute the core elements of the Industrial Environmental Management (IEM) program I lead at Yale. Industrial ecology, with its focus on the flows of material and energy through systems at different scales, provides the unique intellectual foundation for the IEM program, establishing its global leadership through research, education, and outreach. My overall work focuses on four areas: industrial ecology/industrial symbiosis, corporate environmental management and strategy, waste management, and environmental technology policy and innovation. My industrial ecology research has established industrial symbiosis as a distinctive area of inquiry concerning the cooperative management of resource flows among industrial actors at the inter-firm and regional scales. Over the last several years my most intensive research has 1) continued to develop and test new theories about industrial symbiosis; 2) created a new focus on investigating how industrial ecology can contribute to sustainability issues in resource-constrained emerging economies; and 3) employed industrial ecology’s metabolism approach to explain transformations within human and natural systems in Hawaii and through urban metabolism studies in Singapore. These topics are described here, including the linkages from current to future research. Because my appointment is to an academic professorship that focuses on management, this implies interdisciplinary inquiry, attacking problems using a range of disciplinary theories and methods as discussed below.

Most of my industrial ecology work has centered on nurturing and growing a coherent research program around the concept of “industrial symbiosis” as a collaborative means of reducing environmental impact. As with its biological counterpart, industrial symbiosis concerns mutually beneficial exchange of materials, energy, and information across unrelated units, in this case, firms in relative geographic proximity.  My early research was concerned with describing and categorizing industrial symbiosis when it was first being observed in the 1990s to frame the discussion.  Since then, I have led pioneering investigations concerning what factors motivate industrial symbiosis, under what circumstances it emerges, how ubiquitous and resilient the resulting industrial ecosystems are, their significance in economic and environmental terms, and the depth of the ecological analogy.

Institutionally, I founded the Industrial Symbiosis Research Symposium to bring together international colleagues to build the body of scholarship in this area. The Symposium was convened and hosted first at Yale (2004), then in Stockholm (2005), Birmingham, UK (2006), Toronto (2007), Devens, Massachusetts (2008), Kalundborg, Denmark (2009) and is planned for Kawasaki, Japan (November 2010). The symposia provide a unique opportunity for international exchange and debate over research trends and priorities, as well as inspiration to the rapidly growing next generation of IS researchers. These meetings have catalyzed academic books and peer reviewed articles creating knowledge that is also usable for professional practice in this area. Over the last six years, national programs implementing industrial symbiosis have arisen in the U.K., Korea, and China. Most recently, an ambitious European Union-wide program was launched to bring three million industrial companies to industrial symbiosis partnerships using my definition of the term. In 2009, the industrial symbiosis chapter was launched within the International Society for Industrial Ecology and in 2010 the world’s first doctoral program in industrial symbiosis, to which I am an advisor, began in Sweden.

Working with colleagues and students in multi-year, grant-funded projects in Puerto Rico, Hawaii, India and China, I have applied a variety of quantitative and qualitative methods from various disciplines to investigate whether and how industrial ecosystems self-organize, develop, function, and adapt.  These efforts include:

  1. Integrating industrial ecology, ecosystem ecology, and complex adaptive systems
    Combining field research results from my project sites across the world with recent findings from ecosystem ecology that revealed resilient ecosystems to be constantly in flux (Chertow 2009), and the important role played by self organization and spontaneity (Chertow 2007), I have reconceptualized how industrial ecosystems are organized, evolve and ought to be stimulated. This has led to the development of a theory of industrial symbiosis based on a three-stage emergence model of industrial ecosystems progressing from co-located firms seeking economic efficiency, to conscious recognition of network benefits, to institutionalization of beliefs and norms enabling successful collaboration among firms (Chertow and Ehrenfeld, 2010 – in review). This theory is being put into practice by public and private sector agents who are recognizing the need to build on existing relationships to create eco-industrial networks rather than planning eco-industrial parks from scratch.
  2. Measuring economic and environmental costs and benefits
    With respect to substantiating the “business case for industrial symbiosis” I conducted the first quantitative analysis of the costs and benefits to private actors from resource exchange, which revealed substantial, but unevenly distributed economic and environmental benefits (Chertow and Lombardi, 2005).  The methodology was advanced by addressing whether firms are better off pursuing symbiotic exchanges or working alone, with results substantiating the importance of a collective approach (Chertow and Miyata, 2010).  A study of secondary material use in Pennsylvania broadened the spatial scale to the state level, the temporal scale to the product lifecycle and the organizational scale to more than 10,000 facilities, with a key finding that the previously unrecognized and uncounted energy savings from reusing these materials exceeded the output of the state’s renewable energy program (Eckelman and Chertow, 2009).
  3. Determining the importance of social networks
    Social network analysis (SNA) has revealed new insights into the functioning of organizations and social systems in many areas – from workplace relationships to international trade. Under my tutelage, the first formal SNA in the field was used to demonstrate the role of social capital in the operations of industrial symbiosis networks, revealing that symbiotic ties were steeped more in trust and personal relations than typical supply chain links and that trade associations can play an important role in breaking down inter-firm barriers (Ashton PhD thesis, 2008). Data from India have now been collected for a second SNA, with researchers at other institutions adopting this tool and approach. A recent publication highlighted the importance of including social considerations in understanding industrial symbiosis, by examining the role of social embeddedness within industrial symbiosis linkages (Chertow and Ashton 2009). The social science perspective espoused in this line of work is now seen as an area of significant growth for industrial ecology.
  4. Applying agglomeration economies and transaction cost economics
    The concept of agglomeration economies from economic geography has come to the fore as many regions seek to attract and retain companies in their locales that improve their comparative advantage with other regions. My work has demonstrated that agglomeration benefits can be enhanced by industrial symbiosis because IS encompasses positive environmental externalities not previously counted, for example by lowering emissions through shared utilities and byproduct reuse (Chertow, Ashton, and Espinosa, 2008). In addition, I have shown that transaction costs play an important role in firms deciding whether to pursue symbiotic exchanges (Ehrenfeld and Chertow, 2002).  The first significant engagement of industrial symbiosis within transaction cost theory, a statistical study of ownership arrangements and transaction costs in a Chinese industrial park (Shi PhD thesis, 2009), was completed under my guidance.

I am keen to maintain my leadership role by exploring new insights in industrial symbiosis through engagement with other scholars and fields. Over the next several years my research group will continue to:

  1. Build theoretically on the concept of industrial ecosystems as complex adaptive systems and continue to look for patterns across industrial ecosystems;
  2. Investigate empirically the types of knowledge developed and the business organization of firms that successfully engage industrial symbiosis adding a behavioral economics element; and
  3. Shape a deeper understanding of the economics of what materials are reused and how these markets develop, including integration of this topic with our studies of developing country contexts.

Since 2007, the Yale Program on Industrial Ecology in Developing Countries has been working with international colleagues to adapt industrial ecology theory and practice to the realities faced in developing countries related to the intertwined problems of energy access, water quality and quantity, waste management, and global warming.  An initial paper introduced these concepts broadly, and then for Asian countries, via the Asian Development Bank (Chertow 2007, 2008). Key research efforts focused on China and India include:

  1. Extensive investigation of inter-firm relationships in a 40 km2 industrial park in China’s Tianjin Economic-Technological Development Area (TEDA) to test theories and concepts from industrial ecology and institutional theory (Shi, Chertow, and Song 2010).  My group has helped TEDA evaluate its performance with other leading symbiotic networks and provided additional strategic advice.
  2. Examination of industrial clusters and infrastructure in south India including leather-making, jatropha, and mixed agricultural and industrial areas to understand environmental impacts and collective approaches to addressing resource constraints (Ashton, Chertow and Shenoy, 2009). Most recently, we found remarkably high rates of resource reuse (99.5% of total outputs) in an Indian industrial cluster (Bain, Shenoy, Ashton and Chertow, 2010). Interest by business owners in this cluster in the benefits generated has led the government to announce funding for implementation of additional symbiotic exchanges.
  3. Tracking the creation and implementation of Asian laws in support of more closed-loop “resource circulating societies,” especially given the increasing share of the world’s economic output being produced and consumed in Asia. In particular, China’s 2009 “Circular Economy Promotion Law” is being implemented as a means of balancing China’s rapid economic growth with concern for environmental protection and was noted by the World Bank as being inspired by industrial ecology.

In industrial ecology terms, metabolism involves the transformation of inputs such as raw materials, fuel and water into outputs such as the built environment, human biomass, and waste.  My research in this area encompasses urban and island settings with material and energy analyses in Puerto Rico (2001-2008), Hawaii since 2006 (Johnson and Chertow 2009, Eckelman and Chertow 2009) and Singapore since 2009.  The urban metabolism studies that my students and I are pursuing measure comparable flows through cities and help to determine the magnitude and pace of resource use and exploitation, as well as the changes and threats to water and energy systems in order to open the possibility of improving the efficiency and effectiveness of resource management in urban systems. Specific research efforts are:

  1. Comparing two cities on Hawai’i Island with markedly different socioeconomic and biophysical characteristics over 150 years by conducting material and energy flow analysis and a land cover/land use study through an NSF-funded project related to the Long-term Industrial Ecosystem Model - Hawaii Island (LIEM – Hawaii) that I  launched with partners in Hawaii in May 2009. Early results indicate quite disparate resource management schemes across the two urban areas with respect to wastewater reuse, material recycling, and emissions from fossil fuels.
  2. Examining high-density urban development in mixed-use districts in Singapore at the level of the city building block to characterize and quantify urban metabolism of selected inputs, outputs, and additions to stock through Singapore government-funded research in partnership with the National University of Singapore. The research is intended to guide future city planning for more effective resource management.
  3. Preparing an edited volume with European researchers who integrate socio-ecological material flow approaches into the study of long-term ecological research sites, led by Simron Singh and Helmut Haberl of the Institute for Social Ecology in Vienna.


  • I began an analysis, in consultation with the World Bank, of data indicating that China generates twice as much municipal solid waste as India even with a very similar population. The analysis will track resource flows to explain this situation and will explore the climate and energy effects of current and projected waste generation and management scenarios.
  • Returning to my interest in technological innovation and policy, I have received funding from the Woodrow Wilson International Center for Scholars at the Smithsonian Institution to prepare a study to serve as the basis of the “Clean Slate Project.” The goal is “to redefine environmental protection on the technological frontier,” involving cutting edge thinkers preparing an edited volume.
  • Over a longer time frame, I would like to prepare a book on “restructuring industry” to underscore the results from many years of research about the role of industrial symbiosis in increasing resource productivity and inter-firm collaboration.

My teaching focuses on two topics within industrial environmental management: 1) business and environment and 2) industrial ecology. I teach at the graduate school level at Yale YSE and the National University of Singapore and also in various executive training programs.

  1. Business and Environment
    1. I have taught Business Concepts for Environmental Managers for over ten years teamed with an accounting instructor and Dr. William Ellis. The course offers a way to familiarize environmental students with finance, accounting, and how business tools such as net present value and cost analysis can be understood and used to advance environmental objectives. This course provides a necessary toolkit for those interested in private sector management or in regulating private sector activities.
    2. Corporate Environmental Management and Strategy is cross-listed with SOM. This advanced IEM course has two purposes: 1) to examine the role of environmental management in corporations as well as to describe programs, structures, and tools being implemented; and 2) to discuss the relationship of environmental management to competitive advantage in a systematic way, including under what circumstances different strategic approaches are likely to be successful.
    3. In 2001 I began Business and Environment, a required course in the Masters of Science in Environmental Management Programme at the National University of Singapore. It blends many of the courses I have been teaching at Yale.
  2. Industrial Ecology
    1. I have taught Industrial Ecology in the class led by Professor Thomas Graedel for ten years. My specialties in the class have been tying industrial ecology to waste management, public policy, and technological innovation. In addition, each year I invent and oversee semester long field projects for student teams in industrial symbiosis.
    2. The Advanced Seminar in Industrial Ecology takes a different theme each year. Recent themes I have led were The Environmental Aspects of Emerging Technologies and, most recently, Industrial Ecology and the Circular Economy in China.
    3. In 2004 I taught Greening the Industrial Facility which provides an introduction to the environmental aspects of key industrial sectors through which modern society accomplishes its purposes.
  3. Executive Education.
    1. In the last couple of years I have been teaching executives from 1) the Chinese State Environmental Protection Administration and Ministry of Science and Technology through a program sponsored by the Italian government (2004-2005); 2) the Environmental Management Executive Programme for the Singapore Ministry of Environment and Water Resources (2005-2006; 3) the Public Policy and Sustainable Development Masters Program sponsored by India’s TERI School of Advanced Studies (2006) and 4) the Chinese Communist Party School (Spring and Fall 2006).

B.A., Barnard College, Columbia University; M.P.P.M., Ph.D., Yale University

Marian Chertow in the News