Modeling and Evaluating Circular Scenarios: Industrial Ecology, Agent-based and System Dynamics Approaches

In recent years, the concept of Circular Economy has gained increasing popularity, establishing as the reference paradigm in the transition from linear to circular production systems with the aim of increasing their economic, environmental and social sustainability; however, the complexity of such systems requires an interdisciplinary approach and specific methods and tools to support informed decisions in respect of the implementation of circular solutions. In this regard, Industrial Ecology provides solid methodological basis for mapping systems, quantifying and optimizing material and energy flows and identifying critical aspects of a system and related solutions. Conventional approaches, which are essentially static, do not often capture the dynamic complexity and multidimensionality of the transition from linear and circular production systems. To address this limitation, advanced dynamic modeling techniques, such as Agent-based Modeling and System Dynamics, are currently being studied as potential decision support techniques. Dynamic modeling allows simulating the temporal evolution of systems and analyzing how interactions between components and actors affect overall behavior; in particular: Agent-based Modeling allows the heterogeneous behavior of actors (e.g., firms, consumers, regulators) to be represented and the aggregate effects of their decisions to be explored. System Dynamics, on the other hand, allows the exploration of complex scenarios by modeling the relationships between the variables involved, feedback loops and nonlinear dynamics that determine systemic behavior, highlighting critical points on in which interventions should be focused. This article highlights how static approaches can be integrated with dynamic techniques, such as Agent-based Modeling and System Dynamics, to support strategic decisions for the implementation of one or more circular solutions in a given context and a comparison of the techniques and the main related modeling software available will be presented.