The Need for Realistic Behavior Modeling in Life Cycle Assessment.

Tackling complex environmental problems requires both technological and socio-cultural innovation. Life-cycle assessment methods rigorously and systematically analyze the environmental impacts of products, often focusing on technical parameters. Human behavior is rarely treated with the same level of nuance or complexity, despite having a major influence on the environmental impacts of many products. LCA must evolve to more accurately reflect the role of behavior in the environmental impacts of products. This Perspective provides a framework to identify important human-product interactions that can influence the results of an LCA. Heterogeneous consumer behavior regarding product substitution, use intensity, and lifespan is an important factor that should be explored beyond simple sensitivity analysis or scenario generation. We recommend increased data collection and interdisciplinary collaboration to assess actual consumer behavior, more explicit guidance for integrating consumer behavior into LCAs, and improved communication of behavior-dependent LCA results.