Flood disasters and rural inequality under climate change: A survey-based agent-based model of smallholder farmers in the Pampanga River Basin, Philippines

Abstract

Flood disasters can have profound long-term socio-economic consequences for smallholder farmers, potentially contributing to the emergence of rural inequality under climate change. However, most previous studies on impact assessments have focused on aggregated economic losses, providing limited understanding of how flood impacts accumulate over time at the household level. This study evaluates the long-term socio-economic impacts of recurrent flooding on smallholder rice farmers in Candaba City in the Pampanga River basin, Philippines. The analysis combines climate-driven flood simulations with an empirically calibrated agent-based model representing heterogeneous farming households. Flood inundation is simulated using the WEB-RRI hydrological model driven by dynamically downscaled climate projections under present climate and RCP8.5 scenarios. Model parameters describing household behavior, borrowing, and land transactions are calibrated using local interview and questionnaire surveys. Simulation results show that climate change substantially increases flood-induced economic risks for farming households in several flood-prone barangays. Recurrent crop damage leads to increased household debt and may trigger land ownership transfers from poorer farmers to wealthier households, gradually increasing economic inequality within the community. Although early planting can mitigate flood losses under present climate conditions, its effectiveness declines under intensified future flooding. These findings highlight the importance of coupling high-resolution flood hazard simulations with modeling household-scale economic dynamics when assessing climate change impacts on agricultural livelihoods and designing adaptation strategies for vulnerable rural communities.