Industrial Metabolism

Applications

The concept of industrial metabolism is useful for ecological economics as it provides a way to analyze the flow of physical resources in industrial and societal systems from an integrated perspective, allowing the study of system-wide effects and problem shifting due to environmental policies. It can be usefully applied at many different levels from global through national, regional, sectoral, company, site, and household. At smaller scales, industrial metabolism addresses how resources are used in the human economy through the development of resource-accounting frameworks for political and economic entities, as [Page 325]well as life cycle analyses of the materials used in the manufacture of industrial and consumer products. At the largest scale, it can highlight anthropogenic contributions to atmospheric concentrations of trace gases and the flow of excess nutrients from agricultural activities to water bodies. The information can be used to construct a materials balance of the whole system and draw conclusions regarding the actions needed to improve the environmental character of its metabolism.

Measures of Industrial Metabolism

A useful measure of industrial metabolic efficiency is the economic output per unit of material input, which can be termed materials productivity. In principle, this can be determined for the economy as a whole, as well as for each sector and major nutrient element (e.g., carbon, oxygen, hydrogen, sulfur, or iron).

Various approaches have been developed to measure sustainability, including material flow analysis, physical input–output tables, life cycle assessment, cost minimization models, equilibrium models, and dynamic optimization and system dynamics. Unsustainability can be determined by the amount or degree of dissipative loss (materials that are not reused or recycled) and analyzing the reasons for dissipative loss may help develop systems to improve sustainability. There are three principle reasons why materials are not recycled: recycling may be inherently unfeasible, or technically feasible but not economically viable under current conditions, or both technically and economically feasible, but not occurring for other reasons.

Future Directions

To increase sustainability, the material and energy flows in industrial metabolism must be altered so that they more closely resemble biological metabolism: in particular, by returning more materials currently discarded as waste back into the system through reuse and recycling, rather than simply changing waste from one form to another or moving it from one location to another. This will reduce the amount of virgin materials required as inputs into the system—a change that is necessary as the supply of resources is limited and in some cases close to exhaustion.

Research in the field of industrial metabolism has traditionally been focused on measuring and describing physical flows of economic systems, because economic systems are traditionally viewed as the regulators of industrial metabolism, exerting control through the price mechanism that determines the supply and demand for labor and products. The metabolism of economic systems, however, changes over time, and research on changing industrial metabolism is needed to improve our understanding of how physical materials flow through the economic system.

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