Decadal climate variability and vulnerability of water resources in arid regions of Northwest China

Decadal climate change has evidently posed serious threats and challenges to water resource management across arid regions in China. Thus, vulnerability assessment of water resources has been considered vital to adapt to or cope with the adverse effects of climate change. This paper investigated spatial patterns of decadal climate change and water resources variability in the arid regions of Northwest China based on a GIS analysis. The Budyko hypothesis was used to investigate the climate sensitivity of basin stream-flow. A framework was proposed to assess the vulnerability of water resources as a function of exposure, sensitivity, and adaptability. Results indicated that a significant increase in precipitation and water resources (both surface water resources and groundwater recharge) occurred primarily in Xinjiang Province after the 1980s. Water utilization ratio in arid regions was very high, and groundwater abstraction substantially increased as it exceeded the exploitable volume in the Hexi Corridor, the Tuha Basin, and the north of the Tianshan Mountain. Exposure of water resources to drought in arid regions decreased from the 1960s to the 2000s. The sensitivity of water resource response to precipitation changes varied between regions. Water resources were more sensitive to precipitation variability in the river basins in the Hexi Corridor and inner Mongolia. In most arid regions in China, water resources were evaluated with low adaptability and high or severe vulnerability in the 2000s. In the future, the precipitation is projected to increase significantly under the RCP2.6, RCP4.5, and RCP8.5 scenarios. Particularly, water vulnerability will be significantly reduced as the precipitation increases in most river basins under the RCP8.5 scenario. Water resources in the rivers in the Qaidam Basin, the Qinhai Lake Basin, the inner Mongolia, and the north of Kunlun Mountain will have low or medium vulnerability in the 2030s and 2050s. However, in the Tuha Basin and Hexi Corridor, vulnerability will remain severe in the 2050s despite the significant increase in precipitation and implementation of water-saving measures. Hence, measures that will facilitate sustainable water resource management must be identified and implemented.