Circular Economy Strategies for Reducing Embodied Carbon in US Commercial Building Stocks: A System Dynamics Modeling Approach

Environmental concerns over embodied carbon—which is generated during the extraction, transportation, manufacturing, construction, and disposal of building materials—have been increasing as the industry shifts to renewable energy and grid decarbonization efforts prevail. Commercial buildings, a rapidly growing sector and a major source of embodied carbon, can contribute immensely to the national climate goals by transitioning into a circular economy (CE). Nevertheless, embodied carbon research is rather dispersed, with sparse data on the actual impact of different CE strategies and how they scale on nationwide commercial building stocks. To address this research need, the goal of this paper is to provide policymakers with a conceptual model that depicts the potential of CE strategy portfolios on embodied carbon reduction of commercial building stocks. Using US commercial buildings data from the Energy Information Administration, the authors (1) developed a systems dynamics model to conceptualize and serve as a baseline for calculating existing embodied emissions; and (2) evaluated the influence of various policy packages in terms of their overall emissions reduction potential over a planning horizon between the years 2022 and 2050. Findings of the study highlight the effectiveness of early design and construction CE interventions as compared to end-of-life strategies such as recycling, as well as traditional and business-as-usual approaches. Ultimately, results of the developed model can aid decision-makers to create multiple “what-if” scenarios for their policies, in addition to capitalizing on the most effective strategies for narrowing material loops and curbing embodied carbon emissions.