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Industrial Ecology is a field of study focused on the stages of the production processes of goods and services from a point of view of nature, trying to mimic a natural system by conserving and reusing resources

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Industrial Ecology studies the movement of materials and energy through systems at different scales (from factories, to value chains, to cities and whole economies), seeking ways to conserve and reuse resources.

Industrial ecology is a field of study that explores how things are made, used, and where they end up. Its meaning can be broken up: “industrial” and “ecology.” “Industrial” tells us this field focuses on people and industry, dealing with material goods, nations, businesses, manufacturers, and consumers. “Ecology” tells us this field focuses on an interconnected system: how the players interact and move around resources (energy, water, and materials) to make goods in less wasteful ways, while decreasing environmental impacts. All together, industrial ecology looks at how physical resources move through industrial systems: from raw material extraction, to use and manufacturing, to ways to reuse and recycle.


Marian Chertow

Director of the Center for Industrial Ecology at the Yale School of the Environment, Associate Professor of Industrial Environmental Management

Manufacturing: What goes in to making a window?

Manufacturing: What goes into making a window? A window can weigh 10-20 kg; what happens to all that material pictured that is needed to produce that one object?

As the worldwide demand for goods increases, so does resource extraction to satisfy this demand. Industrial ecology is the most critical field we have to assess this trend, with many practical tools to evaluate how the extraction and movement of resources affects people and the world at large. Industrial ecology looks at the bigger picture: how science, policy, the environment, economics, and society affect (or are affected by) how things get made, used, and disposed or recovered.

Here’s an example, and another way to think about it: consider industrial ecology as metabolism. If you’re Toyota, and you’re making a car, how would you tabulate all of resources you need to make a car? (that’s the Input, in the diagram to the right.) Then, as you go through the process of making a car, what gets put into the car itself? What gets released as an output from each stage of the process as it goes (gases, wastewater, heat energy)? At the end of the day you have made a car, but what are all the flows that come in and out of that process, from sourcing materials, production, and shipping for sale? Just like how your body’s metabolism takes in resources and creates waste, we can think of the metabolism of an industrial process, and break it down and quantify it in an industrial ecology framework.

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Toyota’s Worldwide Metabolism (Toyota Motor Company)

In [an industrial ecosystem] the consumption of energy and materials is optimized, waste generation is minimized and the effluents of one process – whether they are spent catalysts from petroleum refining, fly and bottom ash from electric-power generation or discarded plastic containers from consumer products - serve as the raw material for another process.

This is a relatively new field: “industrial ecology” was first written about in a 1989 Scientific American article titled “Strategies for Manufacturing,” although mentions of it bubble up as far back as the early 1970s[1]. In that 1989 article, the authors consider the implications of industrial ecology:

Frosch and Gallopoulos, Scientific American, 1989


This quote illustrates a larger point: industrial ecology is not only a descriptive tool (quantifying flows), but it can be used as a prescriptive tool to make recommendations for system improvements. By assessing flows of resources, industrial ecology can identify opportunities for waste reuse and reduction. This process can be scaled to look at a single car factory, to all car factories within a company, even to all car factories within a nation. Take another look at the Toyota diagram: you can see a loop (right) that indicates thermal recovery. This shows how waste is already being reused within a system.

Industrial ecology is seen as one of the conceptual underpinnings to the circular economy, another popular idea in creating sustainable processes. The circular economy is a vision of shifting over time from linearity (where materials are discarded from a system as waste) to circularity (where waste is reused as an input somewhere else in the system). A more circular economy would decrease the consumption of finite resources for the benefit of businesses, consumers, and the environment. Achieving this vision depends on political will, business innovation, and technological improvements – and industrial ecology is part of the framework to accomplish it.

Watch Dr. Chertow explain the concept of industrial ecology and review some real-world examples.

Here are some further resources about industrial ecology:

Read about one famous industrial ecology example – industrial symbiosis at Kalundborg, Denmark. Here, companies share numerous physical by-products (from hot water, to gypsum, to organics) among six industrial and three public sector organizations, operating as an “industrial ecosystem”:

The eternal debate: paper vs. plastic? Industrial ecology helps to dig into the nuances, and Northwestern University has the story:

Read about how one company, Apple, is employing reuse in its own production via recycling robots:


 [1] Amit Kapur, Thomas E. Graedel, in Encyclopedia of Energy, 2004

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