Agricultural and energy products trade intensified the water scarcity in the grain and energy base in northern China

As an energy and agricultural product export region that plays a crucial role in Chinese grain and energy security, the grain and energy base in northern China is a widely known ecologically fragile region, suffering from severe water scarcity. This study introduced the water-energy-food (WEF) nexus to assess the impact of agriculture and energy trade on the water stress in the study area. We find that the study area is a virtual water (VW) net outflow area, and the VW outflow with trading of agriculture and energy industry accounts for more than 85 %. The VW mainly flows to economically developed regions or water-abundant regions, which presents a "poor to rich" and "lack to abundant" situation. Although the implementation of water-saving techniques has improved the water use efficiency of nine research departments in the study area during 2012–2017, it is still lower than the national average, especially in agriculture. The contribution of VW outflow through agriculture trade to water stress is 20 %, while that through energy trade is 5 %. Approaches, such as VW compensation and inter-regional joint production, may be useful to balance national WEF safety. Otherwise, the water shortage in the study area is likely to worsen in the future.