Political feasibility constraints global mitigation pathways

Climate policy implementation, often approached top-down, repeatedly misses targets and lacks public support. Classical integrated assessment models (IAMs) cannot explain this mitigation gap, as they treat political factors as fixed, ignoring the dimension of political feasibility. We address this by coupling a multi-regional IAM with an agent-based model (ABM) of 57 regions, each with a government and 1,000 households, to model mitigation pathways from 2015 to 2100. Governments balance international negotiations and domestic pressures from diverse households voting based on attitudes of climate concern, time preferences, and global solidarity. Our results show that meeting Paris targets requires extreme combinations of attitudes. Regional climate vulnerability and within-region attitude heterogeneity render these combinations rare. Early opposition creates path dependencies that lock regions into low-ambition trajectories, even as climate change becomes more apparent. These findings suggest that opinion shifts driven solely by climate experience are insufficient to garner social acceptance for ambitious goals.