Latitudinal variation in temperature dominance of domestic water use across the coastal Chinese mainland

Understanding the drivers of domestic water consumption under climate change is critical for addressing the global water crisis. This study aims to quantify the relative contributions of climatic (temperature, precipitation, water resources) and socioeconomic (GDP per capita, population density, built-up area) factors in driving the spatiotemporal variations of per capita domestic water use (DWUpc) across coastal China during 2011-2022. Compared to previous studies, we examined the climate-human interaction at the prefecture level with the aid of XGBoost-SHAP framework. We found that DWUpc varies substantially (57-306 L/d), generally higher in southern regions but increasing faster in the northern over the past decade. Temperature is the dominant driver (57 % of total variability) over the study area. However, DWUpc exhibits strong latitudinal variation in sensitivity to temperature. Higher socioeconomic development combined with abundant water supply can amplify this sensitivity. The highest-sensitivity zones were identified within 11.5-21.6 °C, where a 1 °C rise could increase domestic water use by 5-13 %. These findings underscore the importance of incorporating latitudinal heterogeneities into future domestic water use projections and region-specific management under the situation of global warming.