Transposing lessons between different forms of consequential greenhouse gas accounting: lessons for consequential life cycle assessment, project-level accounting, and policy-level accounting

Greenhouse gas accounting has developed in a number of semi-isolated fields of practice and there appears to be considerable opportunity for transposing methodological innovations and lessons between these different fields. This research paper identifies three consequential forms of greenhouse gas accounting: consequential life cycle assessment; project-level accounting; and policy-level accounting. These methods are described in detail and then compared in order to identify the key methodological differences and the potential lessons that can be transposed between them. Analysis of the substantive methodological differences suggests that consequential life cycle assessment could be enhanced by adopting the same structure used in project and policy-level accounting, which provides a time-series of impacts, aggregate level analysis, and a transparent specification of the baseline and decision scenarios. There is a case for conceptualising a unified form of consequential time-series assessment, of which project, policy and product assessments would be sub-types.