Attributional and consequential life cycle assessments in a circular economy with integration of a quality indicator: A case study of cascading wood products

The growing popularity of the concepts of circular economy and resource cascade has intensified the need for consistent handling of multifunctionality‐related challenges when modeling multiple cycles in life cycle assessment (LCA). In LCA, end‐of‐life upcycling and downcycling effects (also known as quality changes), triggered by the presence of multiple life cycles, have only recently begun to be studied from a consequential perspective, and no studies exist investigating attributional aspects. In this paper, a novel approach that considers quality in attributional LCA is proposed. The attributional, cut‐off, open loop, and proposed approaches are compared in the form of a cascading case study. The implications of integrating quality in both perspectives are contrasted by modeling the same case study under a consequential perspective. By performing sensitivity analysis on the quality parameters in attributional LCA, we found that the integration of quality influences the results of the proposed approach by up to 15%. In the case of consequential LCA, the implementation of quality yields an influence between 97% and 138% of the results for each unit variation of quality. Comparison between the two perspectives of quality shows the same trend of supporting high‐quality cascades. However, the attributional perspective of quality accomplishes this by redistributing impacts, while the consequential perspective affects the external benefits generated by the cascade. Considering the influence of quality on the results of both perspectives, future work should focus on establishing the technical or economic properties that would allow for practical use of quality in various circular economy and resource cascade applications.