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Water scarcity is a critical threat in arid regions in China due to dry climate and rising human water demand. The sustainability of a recent wetter trend and its impact on future water security remain uncertain. This case study focuses on a hotspot region, the North Slope of the Tianshan Mountains (NSTM), to assess water scarcity in the coming decades (2030–2050) under two climate scenarios. To this end, we developed an integrated agro‐hydrological model to simulate historical and future hydrological processes and crop water dynamics in arid regions. Our results indicate nonsignificant increases in precipitation (around 3%) and evident rising temperatures (0.9–1.5°C) in the NSTM compared to the present‐day (2011–2020) climate. This translates to a projected increase in water availability (5.6%–11.2%) during 2030–2050, with slightly larger increases (6.3%–14%) in glacier runoff. However, the spatial mismatch between precipitation increases and water demand makes this potential gain largely offset by rising irrigation water demand (over 7%) if cropland remains constant from 2020 onwards. As a result, the current annual water deficit (3.3 km3) is likely to increase by 5%–11%, with 32% of NSTM basins facing persistent water scarcity. Most croplands are at high risk of groundwater depletion and 17%–34% of basins will experience intensified water scarcity. These findings highlight the urgent need for comprehensive water management strategies, including improved irrigation efficiency and exploration of alternative water sources, to ensure water security and sustainable development in arid China facing a changing climate. Plain Language Summary: Dry regions in China face a water shortage due to low rainfall and rising water use. Recently, even though more rainfall was observed in some arid regions, scientists aren't sure if this will continue. We focus on the hotspot region, the North Slope of the Tianshan Mountains (NSTM), to see how future climate change might affect water scarcity. We found slightly more rain and warmer temperatures in the coming decades (2030–2050) in the NSTM. This could lead to a small increase in available water. However, the need for irrigation water is expected to offset these gains. The current water deficit is likely to worsen, with some areas facing even greater scarcity and increased risk of groundwater depletion. This highlights the need for better irrigation practices and exploring alternative water sources to ensure water security and sustainable development in these regions under a changing climate. Key Points: Slight increases in precipitation and water availability are projected in the NSTMWater scarcity persists due to the spatial mismatch between increased water availability and high irrigation demandThe water deficit is likely to increase by 5%–11% from the current level of 3.3 km3 per year [ABSTRACT FROM AUTHOR]

Water scarcity, which refers to a deficit of freshwater resources availability in meeting anthropogenic and environmental water needs, is nowadays a growing concern in many countries around the world. Because water scarcity is often poor management induced, research is critical to advance knowledge and provide technical and policy support for water scarcity adaptation and solutions. Here, we address global water scarcity research pattern and underlying drivers, using the bibliometric analysis combined with geographic detector. The results indicate that water scarcity research exhibits great temporal and spatial variations. Predominant factors that control the numbers of water scarcity publications are gross domestic products (GDP) and population, which altogether explain 30–52% of the variance of the number of publications in different countries. Water scarcity research is biased in a few populated and affluent countries. Other factors, including physical water scarcity, research and development expenditure, and governance indicators can also be linked to water scarcity research. Keywords mining reveals that hotspots of research domains on causes, approaches, types, and effects of water scarcity show continental difference. The results have policy implications for guiding future water scarcity research. Research in developing countries suffering from physical and economic water scarcity should be enhanced to improve adaptive capacity and reduce vulnerability to water scarcity. [ABSTRACT FROM AUTHOR]

Human activities, as well as climate variability, have had increasing impacts on natural hydrological systems, particularly streamflow. However, quantitative assessments of these impacts are lacking on large scales. In this study, we use the simulations from six global hydrological models driven by three meteorological forcings to investigate direct human impact (DHI) and climate impact on streamflow in China. Results show that, in the sub-periods of 1971–1990 and 1991–2010, one-fifth to one-third of mean annual streamflow (MAF) was reduced due to DHI in northern basins, and much smaller (<4 %) MAF was reduced in southern basins. From 1971–1990 to 1991–2010, total MAF changes range from -13 % to 10 % across basins wherein the relative contributions of DHI change and climate variability show distinct spatial patterns. DHI change caused decreases in MAF in 70 % of river segments, but climate variability dominated the total MAF changes in 88 % of river segments of China. In most northern basins, climate variability results in changes of -9 % to 18 % in MAF, while DHI change results in decreases of 2 % to 8 % in MAF. In contrast with the climate variability that may increase or decrease streamflow, DHI change almost always contributes to decreases in MAF over time, with water withdrawals supposedly being the major impact on streamflow. This quantitative assessment can be a reference for attribution of streamflow changes at large scales, despite remaining uncertainty. We highlight the significant DHI in northern basins and the necessity to modulate DHI through improved water management towards a better adaptation to future climate change. [ABSTRACT FROM AUTHOR]

Terrestrial water storage (TWS) in high mountain areas contributes large runoff volumes to nearby lowlands during the low-flow season when streamflow is critical to downstream water supplies. The potential for TWS from GRACE (Gravity Recovery and Climate Experiment) satellites to provide long-lead streamflow forecasting in adjacent lowlands during the low-flow season was assessed using the upper Yellow River as a case study. Two linear models were trained for forecasting monthly streamflow with and without TWS anomaly (TWSA) from 2002 to 2016. Results show that the model based on streamflow and TWSA is superior to the model based on streamflow alone at up to a five-month lead-time. The inclusion of TWSA reduced errors in streamflow forecasts by 25% to 50%, with 3–5-month lead-times, which represents the role of terrestrial hydrologic memory in streamflow changes during the low-flow season. This study underscores the high potential of streamflow forecasting using GRACE data with long lead-times that should improve water management in mountainous water towers and downstream areas. [ABSTRACT FROM AUTHOR]

• Effects of water withdrawal and water availability to water scarcity were separated. • Increased water withdrawal intensified water scarcity for 57.5% of global population. • Decreased water withdrawal mitigated water scarcity for several developed countries. • Water availability dominated water scarcity change for 4.8% of global population. Water scarcity has become a major issue to sustainable development. It can be estimated by available fresh water resources and human water withdrawal, which are affected by both climate change and human activities. However, the key drivers for the changes in water scarcity at global scale remain unclear due to large uncertainties in the estimations of the contributions from changes in water withdrawal and water availability. By using a newly reconstructed water withdrawal dataset and multi-model simulations of water availability, this study assessed global water scarcity evolution during 1971–2010 at half degree resolution and monthly time scale by applying the water stress index (WSI). Results showed that WSI increased in areas with 61.1% of global population during 1971–2010, and the increase in water withdrawal (especially agricultural sector) was the key driving factor for areas with 57.5% of global population. Specifically, growing water withdrawal led to increased water scarcity for areas with 21% of global population in spite of rising water availability resulted from climate change, such as in southeastern China, Southeast Asia, southern India, and Central Africa. In contrast, water scarcity mitigated over some developed areas including parts of USA, Europe and Japan with 8.8% of global population, which resulted from decreased human water withdrawal (especially industrial sector) and increased water availability. This study reveals the synergistic or contrary effects of changes in water withdrawal and water availability on the changes in water scarcity over the globe, and provides useful information for regional water planning and management. [ABSTRACT FROM AUTHOR]

• This study addresses if inter-basin water transfer transmit or buffer water scarcity. • This is a first national analysis of inter-basin water transfer and supply chain nexus. • Water transfer infrastructure increasingly supports supply chains of China. • Water transfer overall reduced virtual scarce water embedded in supply chains of China. • Changing water scarcity exposure due to water transfer showed spatial heterogeneity. Inter-basin water transfer (IBWT) infrastructure has been expanding to deliver water across China to meet water demands in populated and industrial areas. Water scarcity may threaten the ability to produce and distribute goods through supply chains. Yet, it is not clear if IBWTs transmit or buffer water scarcity throughout supply chains. Here we combine a national database of IBWT projects and multi-region input-output analysis to trace water transferred by IBWT and virtual scarce water (scarcity weighted water use) from IBWT sourcing basins to production sites then to end consumers. The results indicate that production and final consumption of sectoral products have been increasingly supported by IBWT infrastructure, with physically transferred water volumes doubling between 2007 and 2017. Virtual scarce water is about half of the virtual water supporting the supply chain of the nation. IBWT effectively reduced virtual scarce water supporting the supply chains of most provinces, with the exposure to water scarcity reduced by a maximum of 56.7% and 15.0% for production and final consumption, respectively. IBWT Infrastructure development can thus buffer water scarcity risk to the supply chain and should be considered in water management and sustainable development policy decisions. [Display omitted] [ABSTRACT FROM AUTHOR]