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

Soimakallio et al. (Int J Life Cycle Assess 20(10):1364-1375, 2015) establish the need for baselines in attributional life cycle assessment (LCA) and thereby provide an important milestone in the evolving conceptualisation of both attributional and consequential LCA. The purpose of this commentary is to acknowledge Soimakallio et al.'s contribution, identify its implications for a number previously published papers, critique the use of natural regeneration baselines, and offer some further thoughts on the conceptual nature of attributional and consequential approaches. The methods used in this study were comparative analysis with other forms of attributional inventory and an illustrative example of alternative 'natural' baselines for carbon sequestration. The commentary concurs that attributional LCA requires baselines and that attributional studies are not inventories of absolute emissions and removals, contrary to previous statements by the present author. Nevertheless, a number of previous statements on attributional and consequential methods remain largely unchanged: attributional studies can be aggregated to approximate total (anthropogenic) environmental impacts; substitution is conceptually inappropriate for attributional LCA; and the attributional-consequential distinction can be applied to other forms of environmental assessment such as national, corporate, and community greenhouse gas inventories (attributional), and project and policy-level greenhouse gas assessments (consequential). A further finding is that natural regeneration baselines may not be appropriate for attributional studies and that some arguments in their favour may be symptomatic of a misconception of attributional LCA. Soimakallio et al. (Int J Life Cycle Assess 20(10):1364-1375, 2015) make an extremely useful contribution to the evolving conceptualisation of attributional and consequential approaches, which is highly important for methodological development and choosing the appropriate method for a given purpose.