Effective transition pathways toward circular economy based on integrated process models, economic models, and material flow analysis

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Circular economy initiatives promote advanced material recovery and recycling technologies, material efficiency strategies, and dematerialization solutions. These initiatives are central to policies aiming to mitigate climate change, ensure long-term access to critical materials, and reduce various environmental impacts linked to landfilling and resource extraction. Yet the potential benefits and shortcomings of a large-scale adoption of such circularity strategies remain mostly unexplored and unquantified. Even if the small-scale use of a given technology offers environmental benefits, it does not necessarily follow that these benefits are maintained for a massive adoption of this technology across the entire economy. In fact, the applicability of circular economy strategies depends on multiple factors: the level of contamination of recovered materials; the presence of a sufficient market demand for the recycled materials at different levels of purity; the energy, material, and financial requirements necessary to achieve these levels of purity in recycled materials; and the climate and environmental impacts associated with these requirements; among others. All these factors cannot be linearly extrapolated from the present situation, and extensive scenario development is required to effectively guide circular economy policy choices. Taken in isolation, modeling techniques from material flow analysis, life-cycle assessment, and environmentally-extended input-output analysis can each capture only a limited subset of these factors. The current research program is therefore based on the hypothesis that a coherent integration of these modeling methods is required to define credible transition pathways toward a more circular and sustainable economy. This research program therefore aims to contribute to such an integration through the development of a novel analysis framework. To build this framework, a first task will convert national monetary accounts into a representation of material and energy flows throughout the economy. A second task will develop parametrized prospective models of potential technologies for waste recovery, recycling, dematerialization, and lightweighting. This task will strive to account for the material quality requirements of these technologies, and conversely, their influence on the composition of material flows. A third task will develop an analytical algorithm to coherently integrate the detailed technology descriptions of task 2 in the broader representation of the economy from task 1. This framework will be used to define scenarios of large-scale adoption of recycling and dematerialization strategies, focusing on the circularity of flows of metals and plastics in Canada. These case studies will be evaluated in terms of their overall benefits for climate mitigation, resource conservation, and reduction of other environmental impacts, potentially identifying situations of trade-offs.