Using Attributional Life Cycle Assessment to Estimate Climate‐Change Mitigation Benefits Misleads Policy Makers

Abstract

SummaryLife cycle assessment (LCA) is generally described as a tool for environmental decision making. Results from attributional LCA (ALCA), the most commonly used LCA method, often are presented in a way that suggests that policy decisions based on these results will yield the quantitative benefits estimated by ALCA. For example, ALCAs of biofuels are routinely used to suggest that the implementation of one alternative (say, a biofuel) will cause an X% change in greenhouse gas emissions, compared with a baseline (typically gasoline). However, because of several simplifications inherent in ALCA, the method, in fact, is not predictive of real-world impacts on climate change, and hence the usual quantitative interpretation of ALCA results is not valid. A conceptually superior approach, consequential LCA (CLCA), avoids many of the limitations of ALCA, but because it is meant to model actual changes in the real world, CLCA results are scenario dependent and uncertain. These limitations mean that even the best practical CLCAs cannot produce definitive quantitative estimates of actual environmental outcomes. Both forms of LCA, however, can yield valuable insights about potential environmental effects, and CLCA can support robust decision making. By openly recognizing the limitations and understanding the appropriate uses of LCA as discussed here, practitioners and researchers can help policy makers implement policies that are less likely to have perverse effects and more likely to lead to effective environmental policies, including climate mitigation strategies.

Response to “Attributional life cycle assessment: is a land-use baseline necessary?”—appreciation, renouncement, and further discussion

“…However, perverse outcomes are to be wholly expected if attributional LCA is used (on its own) for decision-making, precisely because the method does not necessarily capture the total impacts of the decision at hand (Plevin et al 2014a). The solution is to recognise that attributional methods, by their very nature, are not sufficient for decision-making (on mitigation actions).…”

“…There is a lively and on-going debate within the life cycle assessment (LCA) community on the conceptual nature and relative merits of attributional and consequential LCA (Plevin et al 2014a;Brandão et al 2014;Hertwich 2014;Suh and Yang 2014;Anex and Lifset 2014;Dale and Kim 2014;Plevin et al 2014aPlevin et al , 2014bPlevin et al , 2014c. Clarifying the conceptual nature of these methods is highly important as it directly affects methodological issues, e.g.…”

Challenges in developing regionalized characterization factors in land use impact assessment: impacts on ecosystem services in case studies of animal protein production in Sweden

“…In particular, the circumstances under which land use impact assessments can yield valuable insights must be clarified-including at what scales-cf. the discussion on the role of LCA in decisionmaking (see for example Plevin et al 2014 andBrandão et al 2014). It is also important to ensure traceability along supply chains, since many products incorporate raw materials derived from multiple locations around the globe.…”

How to manage uncertainty in future Life Cycle Assessment (LCA) scenarios addressing the effect of climate change in crop production

“…the choice between attributional and consequential modelling, (e.g. De Camillis et al, 2013;Plevin et al, 2014;Suh and Yang, 2014). With regard to practical applications of future-oriented scenarios, the systems that have been studied are often complex and come from sectors like waste management and energy (Frischknecht et al, 2009;Münster et al, 2013), transportation (Spielmann et al, 2005), and industry (Cluzel et al, 2013).…”