Land Cover Changes Redistribute China's Water Resources Through Atmospheric Moisture Recycling

Abstract

To achieve sustainable development goals such as mitigating climate change and ensuring food security, China has undergone rapid land use/cover changes (LUCC), including afforestation, grassland restoration, and cropland redistribution, which have substantially transformed the terrestrial surface and affected hydrological conditions and water resources management. However, the hydrological impacts of these changes, particularly through atmospheric moisture recycling processes, remain insufficiently understood. This study quantified the hydrological impacts of LUCC in China from 2001 to 2020 using high-resolution data sets and an atmospheric moisture tracking model. Our findings revealed that LUCC had led to increased evapotranspiration (ET; 1.71 mm/yr) and precipitation (P; 1.24 mm/yr), while decreasing water availability (WA) (P − ET; −0.46 mm/yr). Specifically, forest expansion in the Eastern Monsoon Region and grassland restoration in the Tibetan Plateau and Northwestern Arid Region were the main factors contributing to higher ET. These changes in ET, through moisture recycling, had redistributed precipitation and subsequent WA across regions, increasing WA in the Tibetan Plateau (0.38 mm/yr) while decreasing WA in the Eastern Monsoon Region (−0.59 mm/yr) and Northwestern Arid Region (−1.14 mm/yr). The Northwestern Arid Region experienced the greatest decrease in WA primarily due to significant moisture outflow to the Tibetan Plateau. The study underscores the necessity of integrating moisture recycling into water resources management to address the mismatch between land and water resources. Our results provide valuable insights for sustainable land and water resources management in China.