Conference Agenda

Integrated Assessment Models (IAMs) are foundational tools for assessing climate change impacts and informing policy decisions. However, traditionally, IAMs rely on aggregate variables and decisions of actors representing global regions. As a results, IAMs are criticized for oversimplifying representation of heterogeneity and human behavior, in particular on climate adaptation. This paper introduces the first bidirectional coupling between a Cost-Benefit IAM (RICE50+) and an agent-based model (CRAB) that incorporates multiple adaptation strategies against different climate hazards. Our framework enables climate-economy interactions where global temperature changes affect local flood probabilities and labor productivity, while regional adaptation investments feed back into macro-level damage functions and resources left for mitigation strategies. Using detailed spatial and behavioral data from the Netherlands and USA, we demonstrate significant regional variation in adaptation patterns and efficiency. Cost-benefit analysis reveals consistently positive but regionally variable returns of private adaptations (benefit-cost ratios of 5.0 in USA and 2.0 in Netherlands). Moreover, we find that adaptation complements rather than substitutes mitigation efforts. This coupled modeling approach provides a robust platform for evaluating climate strategies that bridge local adaptation decisions with global climate dynamics.