Climate Adaptive Pilot Cities initiative reduced aggregate emission intensity by 0.284 in 273 Chinese municipalities.

Mitigation and adaptation are recognized as essential pillars for urban sustainability; however, the degree to which adaptation oriented policies contribute to broader environmental improvements remains an unresolved empirical question. This study treats the Climate Adaptive Pilot Cities (CAPC) initiative as a quasi natural experiment to evaluate its integrated impacts on urban pollution and carbon reduction. Utilizing a multi period staggered difference in differences framework on a comprehensive panel of 273 Chinese municipalities from 2011 to 2023, we find that the CAPC initiative significantly improves environmental outcomes, evidenced by a 0.284 decline in aggregate emission intensity. Mechanism analysis reveals that this reduction is driven by informal regulation via heightened public climate risk perception and innovation compensation via green technology advancement. Specifically, the policy initiates a state to society vertical diffusion of environmental norms, where pilot cities function as social amplification stations to foster a broad based social consensus. Notably, policy efficacy depends on local conditions: significant abatement effects are concentrated in high income cities with robust fiscal capacity, non-resource based cities free from carbon lock in, and central or western regions with vast untapped marginal abatement potential. These findings underscore the necessity of dedicated fiscal support and structural reforms to bridge urban resilience with low carbon transitions to ensure inclusive environmental governance.