Performing life cycle impact assessment with the midpoint and endpoint method ReCiPe.

Life cycle assessment (LCA) is a method to understand and reduce the environmental impact of products over their life cycle. Although general guidelines to perform LCAs are available, specific recommendations on performing and reporting the life cycle impact assessment (LCIA) step in a standardized way are lacking. This lack can lead to incomplete results, followed by misinterpretation. In the LCIA step, the magnitude and significance of the potential environmental impacts are quantified and evaluated. Here, we describe how to systematically perform and report the LCIA step, identify the most meaningful LCA results and check their robustness. To develop the procedure, we used the widely applied LCIA methodology ReCiPe, which includes so-called characterization factors that express the environmental impact per unit of emission or extraction for 18 midpoint categories, such as global warming and acidification, and three endpoint categories (human health damage, ecosystem damage and resource scarcity). The characterization factors are developed for three perspectives, addressing inherent value choices in the calculation models. To demonstrate its use, our method was applied to a passenger car tire case study. We argue for the inclusion of all three endpoint categories and all three perspectives in the initial assessment. Furthermore, we recommend including a midpoint-to-endpoint contribution analysis on the impact results to identify the most important midpoint categories. Being comprehensive on the LCIA results will lead to a clear, distilled message to stakeholders to decrease environmental impacts, without unintended burden shifting across the supply chain or between different environmental impacts.