Economic models used in consequential life cycle assessment: a literature review

A life cycle assessment framework for large-scale changes in material circularity

Increasing material circularity is high on the agenda of the European Union in order to decouple environmental impacts and economic growth. While life cycle assessment (LCA) is useful for quantifying the associated environmental impacts, consistent LCA modeling of the large-scale changes arising from policy targets addressing material circularity (i.e., recycled content and recycling rate) is challenging. In response to this, we propose an assessment framework addressing key steps in LCA, namely, goal definition, functional unit, baseline versus alternative scenario definition, and modeling of system responses. Regulatory and economic aspects (e.g., trends in consumption patterns, market responses, market saturation, and legislative side-policies affecting waste management) are emphasized as critical for the identification of potential system responses and for supporting regulatory interventions required to reach the intended environmental benefits. The framework is recommended for LCA studies focusing on system-wide consequences where allocation between product life cycles is not relevant; however, the framework can be adapted to include allocation. The application of the framework was illustrated by an example of implementing a policy target for 2025 of 70% recycled content in PET trays in EU27+1. It was demonstrated that neglecting large-scale market responses and saturation lead to an overestimation of the environmental benefits from the policy target and that supplementary initiatives are required to achieve the full benefits at system level.

Tracking the Environmental Consequences of Circular Economy over Space and Time: The Case of Close- and Open-Loop Recovery of Postconsumer Glass

With the increasing globalization of waste-derived raw materials, region-oriented circular economy measures that stimulate resource recovery can cause far-reaching ripple effects in geographically dispersed markets, with unintended environmental effects. Identifying, quantifying, and characterizing these implications in a multiregional economic system remains challenging. This Policy Analysis aims to track these market-mediated environmental consequences over space and time with high material resolution. It explores a novel avenue of coupling consequential life cycle assessment and a time-series multiregional material-product chains model. The model is applied to two measures to recover postconsumer glass waste in the province of Quebec (Canada): improving closed-loop bottle-to-bottle resource recovery systems and deploying open-loop system for the marketing of glass powder as a supplementary cementitious material. Their environmental consequence trajectories (2030-2050) across a seven-industry and six-region competing symbiosis are examined. In both cases, cost-based optimized results highlight widespread adjustments in eastern North America trade patterns that are expanding over time in response to the coevolution of symbiotic industries. Between 55% and 94% of the environmental benefits are felt beyond Quebec borders. This information can help decision makers better anticipate the in- and cross-border scope of their measures and coordinate across jurisdictions to maximize overall environmental benefits.