A Comment on “Functions, Commodities and Environmental Impacts in an Ecological-economic Model”

Abstract

In a recent paper in this journal, Suh (2004) 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 theoretical and practical use of the integrated hybrid LCA approach. In particular, the interpretation of the downstream feedback term, Cd, is discussed from both a theoretical perspective and a practical implementation perspective. In this paper, two interpretations of Cd are suggested depending on the particular LCA database used. If the LCA database is designed for a demand on the functional unit only, then it is argued that the Cd term is negligible in most applications. If the LCA database is compatible with an arbitrary demand, then it is argued that in most cases the consistent use of the Cd term implies excessive data requirements that are not justified by the potential gains. We then discuss further issues relating to the integrated hybrid LCA model and combining LCA and IOA in general.