From adaptation to overload: how climate risks affect public health?-evidence from China

Climate risks (CR), particularly extreme climatic events, are systematically threatening global public health (PH). However, most of the existing studies focus on the linear relationship between a single climate factor and health outcomes, lack in-depth investigation of the nonlinear relationship between the two, and pay little attention to the multi-dimensional adjustment of socio-economic factors. This paper collects panel data of 30 provinces in China from 2011 to 2023, uses ArcGIS and the quantile method to visualize the spatial and temporal evolution pattern of provincial CR and PH. By constructing a province-year fixed effect model with a square term and a moderating effect model, the nonlinear relationship between the two is systematically explored, and the moderating mechanism and heterogeneity of different social factors are identified. The results show that the response of PH to CR is first actively adapted and then significantly inhibited, showing a significant inverted U-shaped relationship. Digital inclusive finance (DIF) and residents' income level (RI) make the inverted U-shaped curve steeper and push the inflection point to the right, showing the characteristics of efficiency-enhanced adjustment; the energy structure optimization (ESO) makes the curve more gentle and the inflection point move to the left, which is manifested as risk-releasing regulation. According to heterogeneity analysis, environmental regulations intensity and green spaces construction have mitigated the health impacts of CR through buffering effects, while green technological innovation has contributed to the manifestation of the inverted U-shaped relationship. This study confirms the existence of an adaptive threshold in the climate-health system resilience, and elucidates three distinct moderating pathways-financial resilience, economic resources, and energy infrastructure-each operating through different mechanisms.