A Probabilistic Index of Temperature-Induced Economic Vulnerability for Subnational Adaptation Prioritization in China

Developing an evidence-based subnational climate vulnerability index is essential for prioritizing regional adaptation support and ensuring the fair and effective allocation of related resources. However, existing indices often struggle to capture nonlinear links between climatic drivers and economic outcomes, and their largely static perspective overlooks how future uncertainties—arising from mitigation pathways, projected warming, and macroeconomic responses—can reshape both climate risks and regional capacity. To address these gaps, we develop a probabilistic climate–economy risk-assessment framework that propagates these nonlinearities and uncertainties into province-level vulnerability distributions, and use them to construct an integrated vulnerability index that reflects both the central tendency and tail risk of temperature-induced GDP vulnerability. Applied to China, approximately 64.5%–80.6% of provinces are classified as vulnerable, with index values below zero. The index reveals a clear spatial gradient, with vulnerability higher in the east and south: coastal economic hubs such as the Yangtze River Delta and Pearl River Delta, together with tropical Hainan, are most vulnerable, whereas colder northwestern and northeastern provinces are more likely to be resilient. The framework supports flexible adaptation resource allocation and regionally targeted investment prioritization under evolving mitigation pathways.