Embodied Resource Flows and Product Flows

We develop the absorbing Markov chain (AMC) for describing in detail the network of paths through an industrial system taken by an embodied resource from extraction through intermediate products and, finally, consumer products. We refer to this as a resource‐specific network. This work builds on a recent literature in industrial ecology that uses an AMC to quantify the number of times a resource passes through a recycling sector before ending up in a landfill. Our objective is to incorporate into that analysis an input‐output (IO) table so that the resource paths explicitly take account of the interdependence of sectors through their reliance on intermediate products. This feature makes it possible to track multiple resources simultaneously and consistently and to represent both resources and products in mixed units. Hypothetical scenarios about technological changes and changes in consumer demand are analyzed with an IO model, and model solutions generate the AMC database. A numerical example is provided. We identify the three most critical enhancements to the standard IO model that will be needed for analyzing material cycles: the incorporation of waste‐processing sectors, stock and flow relationships, and international trade. The idea is to implement an AMC after each modeling step for analyses, such as tracking a resource extracted in one region to landfills in other regions and evaluating ways to intensify secondary recovery at key junctures in between.