Unraveling the role of moisture recycling in water consumption across different ecosystems in China

Abstract

Water consumption is a critical factor in hydrology and water resources management, especially in regions like China that face significant water scarcity and environmental challenges. Traditional assessments of water consumption primarily rely on evapotranspiration (ET), which fails to account for moisture recycling—the process by which evaporated water returns to the atmosphere and precipitates back onto land. This study introduces Net Water Consumption (NWC) as a novel metric within the moisture recycling framework to provide a more accurate assessment of actual water loss. Using high-resolution datasets on land cover, ET, and atmospheric moisture connections, we evaluated the NWC of various ecosystems in China from 2001 to 2020. Our findings reveal that forests, grasslands, croplands, and barren lands had annual mean NWC of 415, 876, 478, and 69 billion m3, respectively, with net water consumption ratios (NWC/ET) of 46 %, 37 %, 57 %, and 15 %. Notably, the spatial and temporal distributions of NWC differ markedly from conventional ET-based assessments, underscoring the crucial role of moisture recycling in understanding water consumption. Land-cover changes, notably afforestation, drove + 4.26 billion m3/year in forests NWC but reduced grasslands and croplands NWC by −3.54 and −0.91 billion m3/year, respectively. These findings emphasize the necessity of integrating NWC into water management practices to achieve sustainable water resource utilization. By providing a comprehensive understanding of water consumption that incorporates moisture recycling, this study offers critical insights for policymakers addressing the water security challenges posed by climate change and land-use transformations.