How LCA studies deal with uncertainty

In recent years many workers have examined the implications of various sources of uncertainty for the reliability of Life Cycle Assessment (LCA). Indeed, the International Standardization Organization (ISO) has recognised the relevance of this work by including several cautionary statements in the ISO 14040 series of standards. However, in practice, there is a risk that the significance of these uncertainties for the results of an LCA could be overlooked as practitioners strive to complete studies on time and within budget. This paper presents the findings of a survey of LCA studies we made to determine the extent to which the problem of uncertainty had been dealt with in practice. This survey revealed that the significance of the limitations on the reliability of LCA results given in the standards has not been fully appreciated by practitioners. We conclude that the standards need to be revised to ensure that LCA studies include at least a qualitative discussion on all relevant aspects of uncertainty.