Towards Endogenous Agricultural Decision-Making in IAMs: Extending FRIDA to Fertilizer and Livestock Systems

Integrated Assessment Models (IAMs) have historically assessed agricultural behaviour through external, narrative-based scenario analyses, rather than representing behavioural dynamics endogenously. This study extends the behavioural change module of FRIDA, a system dynamics IAM, to the agricultural sector. A fertilizer demand submodule has been developed within the existing endogenous behavioural architecture and dynamically coupled to FRIDA’s Energy module. Simulated fertilizer demand reproduces historical patterns and baseline trends, with reductions emerging entirely from structural feedbacks related to natural gas prices, without requiring exogenous constraints. A conceptual framework for a livestock decision submodule is also presented, grounded in a literature review on livestock producers’ perceptions and decision-making. This extension aims to represent livestock producer decisions endogenously within FRIDA’s behavioural architecture by incorporating interacting drivers such as perceived accessibility, scarcity of behaviour, social norms, habits, and climate risk perception.