Everything is relative and nothing is certain. Toward a theory and practice of comparative probabilistic LCA

Introduction
It is widely recognized that LCA is in most cases relative and contains uncertainties due to choices and data. This paper analyses the combination of the two comparative uncertainties.

Basic concepts
We carefully define the idea of relativity and uncertainty within LCA. We finish off by giving an example of case where inappropriate handling of comparative uncertainties will lead to a misleading result for a decision-maker.

Correlations
We develop a generic framework for probabilistic comparative LCA and analyse at which places correlations may be present. We also discuss the most convenient approaches for handling such correlated uncertainties.

Conclusion
We put the elements discussed in a structure that provides a research agenda for dealing with comparative uncertainties in LCA.

Keywords: Comparative analysis, Correlations, Life cycle assessment, uncertainty

Heijungs, R., J. B. Guinée, A. Mendoza Beltrán, P. J. G. Henriksson, and E. Groen. 2019. Everything is relative and nothing is certain. Toward a theory and practice of comparative probabilistic LCA. International Journal of Life Cycle Assessment  24(9):1573–1579.