Introduction to industrial metabolism

Pros and cons of the approach

Ayres established a framework for industrial metabolism by creating an analogy between organisms and industrial activities. Both are materials-processing systems, self-organizing, and characterized by thermodynamic disequilibrium. Based on this analogy, Ayres applies the biological concept of metabolism to industrial activities, the economic system, and the firm as a basic economic unit. Where biological metabolism is determined by an organism’s imperative to reproduce, industrial metabolism is regulated by human consumption as mediated by an economic system.

One important application of the industrial metabolism perspective is considering how human activities have affected the global distribution of nutrients and resources. Ayres discusses how industrial metabolic activities are not a closed system because they have destabilized the global stocks of nutrients. This kind of destabilization has occurred before in Earth’s history (e.g. in the evolution of organisms capable of anaerobic photosynthesis), but the human-effected destabilization has occurred on a much shorter timeframe, faster than life’s self-organizing principles can adapt and compensate. The conclusion that Ayres draws from this is that we need to pursue recycling and re-use of industrial outputs to reach a sustainable steady state where stocks are stabilized.

Ayres concludes that recycling and re-use are key to approaching a sustainable steady state without any mention of how inputs could be better managed or – at a more fundamental level – how the economic system “regulating” industrial activities is itself flawed and in need of modification. It seems short-sighted to focus on the recyclability of finished products when a more “upstream” solution would be to interrogate the forces driving the process.

In addition to a lack of critique of the economic system and industrial activities, there is no discussion regarding why it might be problematic to create an analogy between organisms and industrial activities. Whereas we can see how metabolism is the foundation of and essential to an organism’s biology, it is morally questionable and historically inaccurate to suggest that, by analogy, industrial metabolism is the foundation of society’s existence, when it so clearly has had deleterious effects on Earth.

Despite its weaknesses, the industrial metabolism framework is useful for how it encourages policymakers to view problems holistically and conceive of solutions that are effective even in the longer-term.


Ayres, R. U. (1994). Chapter 1 Industrial metabolism: Theory and policy, Chapter 1 in Industrial Metabolism: Restructuring for sustainable development, Ayres, R. U., & Simonis, U.E., ed. Available at