Weighting environmental effects: Analytic survey with operational evaluation methods and a meta-method

Abstract

Purpose The purpose of this paper is to supply an open method for weighting different environmental impacts, open to basically different evaluation approaches and open to easy revisions. From the partial, diverse and conflicting weighing methods available, a most consistent and flexible meta-method is constructed, allowing for a transparent discussion on weighting. Methods The methods incorporated are as general as possible, each single one being as pure as possible. We surveyed encompassing operational methods for evaluation, applicable in LCA and in larger systems like countries. They differ in terms of modelling, as to midpoint or as to endpoint; as to evaluation set-up, in terms of collective preferences or individual preferences; and as to being either revealed or stated. The first is midpoint modelling with collectively stated preferences, with operational weighting schemes from Dutch and US government applications. Second is the LCAtype endpoint approach using individual stated preferences, with public examples from Japan and the Netherlands. The third is the integrated modelling approach by economists.Results All methods are internally inconsistent, as in terms of treatment of place and time, and they are incomplete, lacking environmental interventions and effect routes. We repaired only incompleteness, by methods transfer. Finally, we combined the three groups of methods into a metaweighting method, aligned to the ILCD Handbook requirements for impact assessment. Application to time series data on EU-27 consumption shows how the EU developed in terms of overall environmental decoupling. Conclusions The disparate methods available all can be improved substantially. For now, a user adjustable metamethod is the best option, allowing for public discussion. A flexible regularly updated spreadsheet is supplied with the article.

A distance-to-target weighting method for Europe 2020

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Hotspots analysis and critical interpretation of food life cycle assessment studies for selecting eco-innovation options and for policy support

“…This was investigated by selecting 3 sets of ILCD-compliant normalization references (Benini et al, 2014Laurent et al, 2013) were tested. The different sets were selected aiming at covering several perspectives on weighting, namely: distance to target for EU policies considering binding and non-binding target at 2020 ; a previous distance to target set (EDIP) for Europe for 2005 (Stranddorf et al, 2005); two sets considering planetary boundaries (Tuomisto et al, 2012;Bjørn and Hauschild, 2015 1 ); a set which gives relevance to midpoint indicators based on their contribution to impact at the endpoint (Ponsioen and Goedkoop, 2016); a set resulting from the combination of different panel-based approaches (Huppes et al, 2012).…”

Interpretation of comparative LCAs: external normalization and a method of mutual differences

“…Weighting in LCA reflects stakeholder or decision-maker values regarding the relative importance of each impact category and enables the ranking of alternatives (Huppes et al 2012;Cortés-Borda et al 2013). Similar to normalization, weighting is an optional stage in LCIA that is avoided in most LCA studies.…”