Building the theoretical foundation for modeling the circular economy

The idea of the circular economy is increasingly touted by leading sustainable businesses as a best practice. However, the full environmental, societal, and financial benefits of such a circular economy remain largely... [ view full abstract ]

The idea of the circular economy is increasingly touted by leading sustainable businesses as a best practice. However, the full environmental, societal, and financial benefits of such a circular economy remain largely theoretical. We propose linking two existing modeling methodologies to provide a theoretical foundation for evaluating the impacts of circular production systems as well as an applied framework for measuring the sustainability tradeoffs in specific supply networks. We will use a modified version of the Rectangular Choice-Of-Technologies (RCOT) version of the World Trade Model (WTM), an economic linear programming model that simultaneously captures the physical and economic aspects of production inputs and supply networks, to track circular flows of waste for inputs into alternative production technologies. We combine this model with our existing Food System Supply-chain Sustainability (FoodS3) model that moves agricultural commodities across the US, linking county agricultural production to meat production. Linking the movement of corn from farms to processing facilities makes it possible to characterize the spatially explicit environmental impacts associated with specific industries, supply chains, “feed sheds” and facility locations. We characterize this joint framework for the US hog industry to demonstrate how connecting our models can theoretically test the environmental benefits of the circular economy. This approach connects both spatially explicit consequential life cycle assessment modeling of US pork production and environmental extended input-output modeling of the global economy. By focusing on food waste and hog production for this proof of concept, this approach will also explore current vs circular inputs into animal production with the objective of evaluating the sustainability tradeoffs of using food waste in animal feed.   Since animal production has been identified as an important contributor to greenhouse gas (GHG) emissions, a circular approach has the potential to substantially reduce life-cycle GHG impacts along with other important environmental and social issues.