A comment on “Functions, commodities and environmental impacts in an ecological-economic model”

In a recent paper in this journal, Suh [Suh, S., 2004. Functions, commodities and environmental impacts in an ecological-economic model. Ecological Economics 40 (4), 451-467.] presented a model combining life cycle assessment (LCA) with input-output analysis (IOA); termed “integrated hybrid LCA”. In this paper, we discuss various issues relating to the use of the integrated hybrid LCA approach. In particular, the interpretation of the downstream feedback term, Cd, is discussed with particular focus on practical implementation. In this paper, two interpretations of Cd are suggested depending on the particular LCA data used. If the LCA data is designed for a demand on the functional unit only, then it is argued that the Cd term is negligible in many applications. If the LCA data is compatible with an arbitrary demand, then it is argued that in many cases the consistent use of the Cd term implies data requirements that may not be justified by the potential gains.