Dynamics and attributions of ecosystem water yields in China from 2001 to 2020
Yiran Li, Peng Chen, Yong Niu, Yushi Liang, Tianxing Wei
Abstract
China is plagued by water security and its associated environmental issues under climate change. Clarifying the spatial and temporal changing patterns of ecosystem water yield (WYe) and its driving factors is essential for optimizing climate-resilient development strategies and achieving sustainable development goals. However, the understanding of the spatial and temporal dynamics of WYe changes in China based on continuous time series and their dominant factors has been limited. This creates a challenge to accurately assess water resource dynamics and environmental sustainability under climate change. Therefore, this study explored WYe dynamic trends in China at the grid-scale from 2001 to 2020 based on water balance and remote-sensing datasets. The contribution and dominance of vegetation (leaf area index and net primary productivity), climate (temperature, wind speed, relative humidity, and net radiation), and human activities, were examined. Results showed that WYe changes exhibited an overall increasing trend (3.0 mm/yr, p = 0.1) in China, with 61.5 % and 38.5 % of the regions showing increasing and decreasing trends, respectively. Climate change (dominant area share, 43.6 %) was the primary driver of WYe dynamics in China, followed by vegetation change (23.8 %) and human activities (21.5 %). The dominant driving factors contributing to WYe dynamics in nine river basins were temperature, net primary productivity, net radiation, and relative humidity. The results emphasize that the high spatial heterogeneity of climate-driven WYe changes may exacerbate regional inequalities in water resources. Future vegetation-driven climate intervention programs and ecological restoration should be implemented more cautiously, and regional adaptive programs must be considered to avoid worsening water scarcity further.