Modelling the impacts of policy, climate and socioeconomic change on water security in China

The management of water resource in China has been under pressures due to rapid socioeconomic growth that escalates the demands in food, energy and domestic sectors, which rely on reliable water provision. Together with climate change, water security is expected to face greater uncertainty in the future. To support sustainable water resource management, this study established a system dynamic model to investigate the impacts of policy, socioeconomic and climate change on water security in China during 2025 to 2100. Five policy options related to carbon neutrality and water management, three socioeconomic and climate scenarios (SSP1-RCP2.6, SSP2-RCP4.5 and SSP5-RCP8.5) were considered. The results show that water demand and water resource will both be greater in the future. Under BAU, water demand will reach 514, 544 and 717 km³ while water resource will increase to 989, 992 and 1032 km³ in 2086-2100 under SSP1-RCP2.6, SSP2-RCP4.5 and SSP5-RCP8.5, respectively. Future water demand for food sector is expected to decrease slightly and then increase under SSP1-RCP2.6, while it shows continuous increase under SSP2-RCP4.5 and SSP5-RCP8.5 due to the changes of planted area, livestock and temperature. Water demand for domestic sector will decrease under three SSP-RCPs because the population will reach a peak around 2030 and then decrease with time. Water demand for energy is expected to decrease under SSP1-RCP2.6 while it will increase under other SSP-RCPs because of more energy demand under SSP2-RCP4.5 and SSP5-RCP8.5. China may face low water security pressure without policy intervention in the future especially under SSP5-RCP8.5. The analysis shows that bioenergy-oriented agriculture cannot mitigate water scarcity risks in China, while low-carbon agriculture strategies can potentially ensure water safety under carbon neutral goal. Water scarcity can be averted if we follow the development path of SSP1-RCP2.6 as well as apply interventions on water management combining with carbon neutral policies that focus on low-carbon agriculture and supplemented by low fossil energy.