Abstract
PurposeWeighting can enable valuable support for decision-makers when interpreting life cycle assessment (LCA) results. Distance-to-target (DtT) weighting is based on the distance of policy (desired) targets to current environmental situations, and recent methodological DtT developments are based on a weighting perspective of a single region or country, considering mainly environmental situations in consuming countries or regions. However, as product supply chains are spread over many countries, this study aims at developing additional weighting approaches (producer regions and worst-case regions) and applying them in a theoretical case study on a global scale.MethodsThe current study is carried out to understand the influence of and the effect on weighting results of different countries and regions with their specific environmental policy targets. Based on the existing Ecological Scarcity Method (ESM), eco-factors for the three environmental issues climate change, acidification, and water resources were derived for as many countries as possible. The regional eco-factors were applied in a case study for steel and aluminum considering the three different weighting approaches on different regional scales.Results and discussionThe analysis revealed significant differences in the obtained weighting results as well as strengths and limitations in the applicability of the examined perspectives. Acidification was showed to be highly important with between 80 and 92% of the aggregated weighting results among the perspectives where water-scarce countries were not involved. Water-scarce countries had a significant influence (75–95%) when they were part of the examined case study.ConclusionsThe developed approaches enable the assessment of global value chains in different producer regions as well as the utilization of the conservative worst-case-regions approach. The approaches can foster future decision-making in LCA contexts while providing country-specific results based on different weighting perspectives in national, regional, and global contexts. However, for a complete implementation of the presented approaches, further data gathering is needed on environmental situations and policy targets in different countries as well as regionalized life cycle data.
Highlights
Life cycle assessment (LCA) studies inform decision-makers in industry, government, or non-government organizations for strategic planning purposes or prioritization among different product options (ISO 14040 2006)
Contrasting results of life cycle assessments are ambiguous and show tradeoffs among different environmental impacts that do not allow a straight forward conclusion. In this context, weighting in LCA can have an important role in the decisionmaking process
Distance-to-target (DtT) weighting methods can derive their weighting factors from democratically legitimized policy targets of the country to be considered, which can strengthen the acceptance of the method among different stakeholders in comparison to other methods
Summary
Life cycle assessment (LCA) studies inform decision-makers in industry, government, or non-government organizations for strategic planning purposes or prioritization among different product options (ISO 14040 2006). Int J Life Cycle Assess (2021) 26:114–126 accepted consensus method seems to be feasible (Sala and Cerutti 2018). The ongoing relevance and importance of weighting in LCA (Pizzol et al 2017; Zanghelini et al 2018) has resulted in a wide range of existing methods. Both political (e.g., Sala and Cerutti 2018) and corporate (e.g., Ahbe et al 2018; Vargas-Gonzalez et al 2019) interest can be observed in the further development of weighting. Different reviews and assessments of existing weighting approaches have been carried out (Huppes and Oers 2011; Huppes et al 2012; Ahlroth 2014; Finkbeiner et al 2014; Pizzol et al 2015, 2017), whereas the most common approaches are panel weighting, monetary weighting, and distance-to-target weighting
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