Integrated human–water–carbon feedbacks driven by large-scale ecological restoration in semi-arid northern China

Large-scale ecological restoration represents a profound human-driven land-use and water management change in semi-arid environments, reshaping coupled human–water systems through complex feedbacks among land use, hydrology, and ecosystem productivity. However, the integrated socio-hydrological consequences of such changes remain insufficiently quantified at regional scales. Here, we synthesize recent empirical evidence from the Loess Plateau and the Mu Us Sandyland in northern China to assess how ecological restoration and related human activities alter soil erosion, water resources, carbon redistribution, and land productivity. Using multi-source remote sensing, socio-economic statistics, GRACE satellite observations, and process-based modelling frameworks, we quantify long-term changes in soil erosion, evapotranspiration (ET), terrestrial and groundwater storage, soil organic carbon (SOC) redistribution, and gross primary productivity (GPP) over the past four decades. Results show that vegetation restoration and ecological infrastructure have substantially reduced soil erosion and enhanced land productivity across the Loess Plateau, particularly since 2000. Concurrently, erosion-induced lateral SOC transport decreased by approximately 21%, indicating a strong coupling between erosion control and regional carbon dynamics. However, these ecological gains are accompanied by increasing water demand. Vegetation greening emerged as the dominant driver of rising ET and GPP, while ecological restoration, irrigation expansion, and mining activities jointly accounted for nearly 80% of observed terrestrial and groundwater storage decline in water-limited regions. These findings reveal reinforcing and counteracting feedbacks in human–water systems, where ecological restoration simultaneously improves ecosystem services and intensifies water stress. Our study highlights the necessity of integrating hydrological constraints into ecological restoration planning and provides socio-hydrological insights for balancing environmental recovery, water sustainability, and human development in semi-arid regions.