Behavioural Dynamics in Agriculture within IAMs: Extending the FRIDA Model with Fertilizer and Livestock Decision Modules

Integrated Assessment Models (IAMs) have traditionally relied on exogenous assumptions of human behaviour, rather than representing endogenously the social systems dynamics that influence decision-making under climate change. Within this context, the FRIDA model addresses a key limitation of conventional IAMs by introducing a fully endogenous behavioural change modelling framework, allowing behavioural representations to be extended across multiple domains.

This study aims to extend the FRIDA behaviour change module by advancing the endogenous representation of agricultural decision-making. It extends the FRIDA decision-making framework to develop a producers’ behaviour submodule that will extend FRIDA’s endogenous representation of decision-making in agriculture, including crop and the livestock sectors. A fertilizer demand submodule, structured in line with existing behaviour change components, explicitly focuses on perceived accessibility, reflecting economic and systemic constraints that can limit fertilizer use. To represent these dynamics, the submodule is dynamically linked to the Energy module of FRIDA, allowing fertilizer demand to respond endogenously to changes in natural gas prices and availability. For the livestock sector, this study incorporates key drivers of decision-making, including attitudes toward practices, perceived climate change risk, habits and social norms, which have been shown to affect the adoption of sustainable land-use strategies, such as integrated systems (IRs) and sustainable animal housing systems.

Preliminary results show a reduction in fertilizer demand that is endogenously driven, avoiding the need for exogenous caps. Results for the livestock sector are pending additional model development.

This work is supported by FCT, I.P./MCTES through national funds (PIDDAC): LA/P/0068/2020 - https://doi.org/10.54499/LA/P/0068/2020 , UID/50019/2025,  https://doi.org/10.54499/UID/PRR/50019/2025, UID/PRR2/50019/2025. This work has also received funding from the European Union’s Horizon 2.5 – Climate Energy and Mobility programme under grant agreement No. 101081661 through the 'WorldTrans – TRANSPARENT ASSESSMENTS FOR REAL PEOPLE' project.