Why life cycle impact assessment is now described as an indicator system

SETAC and ISO now describe the LCIA outcome as LCIA indicators. This contrasts with a SETAC definition of LCIA that is less than five years old. This commentary discusses the two themes that underlie this change in terms and definitions. The first theme is the arrival of a consensus that current LCIA indicators do not describe actual environmental impacts or effects. The second theme is the recognition that some of the ways used to generate indicators results in subjective scores while other ways involve highly simplified assumptions about complex environmental processes. The outcome of the new description is a new emphasis on LCIA transparency. Both the environmental relevance and the scientific basis of each indicator must now be described according to ISO. This increased transparency is essential for decision makers to understand the usefulness of LCIA indicators in making decisions and for audiences to understand what an LCA does or does not say about a product system.