Recent Advances in Life Cycle Assessment and Other Sustainability Metrics

ABSTRACT This article is a review of advances in sustainability metric (SM), focusing on life cycle assessment (LCA) and material flow analysis (MFA), the most commonly used among all SMs. The presentations at the past 10 Society and Materials (SAM) conferences were used as a database. LCA, the most popular of these methodologies, is thriving among academics, practitioners and clients. Standardized initially by United Nations Environment Program (UNEP) and the European Commission, it passed from the Global North to the Global South and branched into Environmental Product Declarations (EPDs) that provide LCA‐formatted information, initially to the construction sector. Some important issues have progressed but are not completely resolved yet: multifunctional products or processes, circulatory practices, dynamic LCA, regionalization, monetarization, human and eco‐toxicity, biodiversity loss or resource availability, and they need more development work. Although LCA focuses on a microscale vision of the economy, MFA, being macroscale, emphasizes strategic and policy issues, thanks to its dynamic version. MFAs are now available for at least one third of the substances in the periodic table and for countless materials, from metals, to composites and construction aggregates for civil engineering. MFA has shed light on many strategic issues, such as (1) the fate of end‐of‐life goods and of the materials of which they are made, which constitute the so‐called urban mine, (2) the role of stocks in driving material demand and long‐term evolution of production (the so‐called Intensity‐of‐Stock model), (3) the connections with economic and social models that extend the scope and ambition of MFA, and (4) material flow accounting (MFAc), particularly Total Material Requirement (TMR). These two SMs are entirely devoted to objectifying the connection between human activities and the environment, mostly, based on quantitative indicators originating from Sciences, Technology, Engineering and Mathematics (STEM). However, LCA and MFA have left aside the full depth of society’s dynamics, as described by Social Sciences and Humanities (SSH) disciplines. Contributions from SSH disciplines do not match the indicator‐based approach: they explored the concepts of social value of materials and social acceptance, used non‐engineering metaphors to report on hard‐science issues, called on Humanities, from History to Literary Criticism, on Science and Technology Studies (STS), on Design studies, on Ethics or Gender issues to shed light on sustainability issues. How the divide between SSH and SMs can be bridged is not yet fully clear. However, attempts were made to develop approaches that would mimic SMs: Social Cycle of Materials (SCM) mixes Design philosophy with STS, and ANT‐reliant LCA , which posits that materials have agency, takes on board Actor Network Theory (ANT) , a sociological model of society as a whole, to report on objects described by LCA. In between STEM and SSH approaches, lie approaches based on thermodynamics, which claim that physics can tackle social and economic dimensions: thermoeconomics is one of them.