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Uncertainty Analysis in Life Cycle Assessment (LCA): Case Study on Plant-Protection Products and Implications for Decision Making (9 pp + 3 pp)

Geisler, Georg ; Hellweg, Stefanie ; Hungerbühler, Konrad

In: The International Journal of Life Cycle Assessment, 2005, vol. 10, no. 3, p. 184-192

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    Titre
    • Uncertainty Analysis in Life Cycle Assessment (LCA): Case Study on Plant-Protection Products and Implications for Decision Making (9 pp + 3 pp)
    Auteur
    • Geisler, Georg. Dr. Georg Geisler Institut für Chemie und Bioingenieurswissenschaften Gruppe Umwelt und Sicherheitstechnologie ETH Zürich ETH Hönggerberg, HCI G 143 CH - 8093 Zürich SCHWEIZ
    • Hellweg, Stefanie. Dr. Stefanie Hellweg Institute of Chemical- and Bioengineering Swiss Federal Institute of Technology Zürich, HCI 8093 Zürich SCHWEIZ
    • Hungerbühler, Konrad. Prof. Dr. Konrad Hungerbühler Laboratory of Technical Chemistry Head of Safety & Environmental Technology Group ETH Zürich 8093 Zürich SWITZERLAND
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • The International Journal of Life Cycle Assessment, 2005, vol. 10, no. 3, p. 184-192. Ecomed
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:316677
    Summary
    Goal, Scope, and Background: Uncertainty analysis in LCA is important for sound decision support. Nevertheless, the actual influence of uncertainty on decision making in specific LCA case-studies has only been little studied so far. Therefore, we assessed the uncertainty in an LCA comparing two plant-protection products. Methods: Uncertainty and variability in LCI flows and characterization factors (CML-baseline method) were expressed as generic uncertainty factors and subsequently propagated into impact scores using Monte-Carlo simulation. Uncertainty in assumptions on production efficiency for chemicals, which is of specific interest for the case study, was depicted by scenarios. Results and Discussion: Impact scores concerning acidification, eutrophication, and global warming display relatively small dispersions. Differences in median impact scores of a factor of 1.6 were sufficient in the case study for a significant distinction of the products. Results of toxicity impact-categories show large dispersions due to uncertainty in characterization factors and in the composition of sum parameters. Therefore, none of the two products was found to be significantly environmentally preferable to the other. Considering the case study results and inherent characteristics of the impact categories, a tentative rule of thumb is put forward that quantifies differences in impact scores necessary to obtain significant results in product comparisons. Conclusion: Published LCA case-studies may have overestimated the significance of results. It is therefore advisable to routinely carry out quantitative uncertainty analyses in LCA. If this is not feasible, for example due to time restrictions, the rule of thumb proposed here may be helpful to evaluate the significance of results for the impact categories of global warming, acidification, eutrophication, and photooxidant creation