The projected futures of water resources vulnerability under climate and socioeconomic change in the Yangtze River Basin, China

Despite being one of the most abundant water resources globally, the Yangtze River Basin (YRB) region is facing substantial risks aggravated by climatic and anthropogenic changes. Here, we adopted an integrated framework to investigate the plausible futures of water resource provisioning in YRB under current and future conditions on the sub-watershed level: (i) a process-based model (InVEST) was used to project the water yield of the whole of YRB in the nearest future (2040-2060) and distant future (2080-2100) and (ii) a socio-ecological index was developed to assess the spatio-temporal patterns of water resources vulnerability (WRV). Model projections indicated that several water-rich areas in the southeastern YRB would suffer declining water yield in the future. While water yield was projected to increase in some drier regions in the northwest. Future changes in the basin-level vulnerability were projected to decrease under low emissions scenarios (RCP2.6) combined with a sus-tainability socioeconomic scenario (SSP1). The greatest increase in vulnerability was projected under the medium-to-high end (RCP7.0) rather than high-end (RCP8.5) climate change scenario. The areas with high WRV were distributed in sub-watersheds near Taihu Lake and the source of the Yangtze River. Climate and socio-economic change were projected to have different roles in shaping the future dynamics of WRV, with precipi-tation reduction and water consumption increase being likely to result in increased WRV levels in the southeastern lower reaches and the middle reaches, respectively. Our study added new spatial data on projected water resource dynamics for the region of vital ecological and economic importance in Asia. The areas prone to increased WRV should be prioritised in future water resources management practices. The assessment approach used in this study integrated concurrent measures from both subjective and objective perspectives and could be used in relevant studies on exploring how future vulnerability could respond to environmental changes.