Better Together: A Review of Approaches for the Integration of Life Cycle and Circularity Assessment

Abstract The European Green Deal outlines the European Union’s strategy to achieve a fair, resource-efficient, and competitive economy with net-zero greenhouse gas emissions by 2050, for decoupling economic growth from resource consumption. Different tools for quantifying a firm’s sustainability and circularity impacts have been developed over the years. While Life Cycle Assessment (LCA) has standardised the calculation of environmental impact, circularity assessment (CA) methodologies are still being developed. The International Organisation for Standardization (ISO)’s recent 59,000 family of standards is an attempt to harmonise CA and circular economy terminology. Moreover, there has been a growing interest among researchers to combine LCA and CA to address the trade-offs between these two tools. Therefore, this paper presents a systematic literature review to explore how LCA and CA are currently integrated. Using a systematic mapping approach, the studies were analysed based on frameworks or methodologies, system levels, sustainability dimensions, circularity indicators and stakeholder engagement. The review finds that the most common approach involves embedding CA into the four-phase LCA framework (ISO 14040), although only a minority of studies consider the social and economic dimensions or involve stakeholders. Assessments remain predominantly at the product level, limiting systemic insight. The paper critically examines these gaps in light of the ISO 59,000 standards and proposes directions for harmonising assessment tools. This study provides valuable insights for researchers, practitioners, and policymakers aiming to apply integrated LCA-CA approaches aligned with emerging standards.