National-scale hydroclimatic exposure screening of earthen heritage sites in China under changing precipitation regimes

Earthen heritage sites are highly sensitive to rainfall-induced erosion and moisture-related deterioration, yet their national-scale hydroclimatic exposure remains insufficiently quantified. Here, we compiled a geospatial database of 1,305 national-level earthen heritage sites in China and developed a spatial screening framework that integrates site-distribution analysis, environmental and anthropogenic factor detection, historical precipitation trends, trend persistence and projected annual maximum 1-day precipitation (RX1DAY). The sites showed a strongly clustered pattern, with high-density areas concentrated in the middle and lower Yellow River Basin and adjacent river-basin regions. Slope had the strongest individual association with site distribution, followed by nighttime light intensity, whereas the precipitation-temperature interaction produced the highest combined explanatory power. During 2001–2020, 94.4% of sites were located in areas with increasing precipitation, indicating widespread chronic wetting exposure. However, future mean RX1DAY was consistently highest in medium-exposure zones rather than high-exposure zones, revealing a spatial mismatch between persistent historical wetting and acute extreme-rainfall hazard. The inconsistency between historical rainfall-exposure levels and projected extreme-precipitation hazard indicated that both long-term and event-driven hydroclimatic pressures should be evaluated separately. This will provide a scientific basis for national-scale heritage exposure screening and climate-adaptive conservation planning.