New challenges of food security in Northwest China: Water footprint and virtual water perspective

In this study, the water footprint (blue, green and grey WF) and virtual water theory were used to uniform measure the new challenges (population growth, population urbanization, dietary structure change, energy industry development, grain trade and climate change) of food security in Northwest China. Moreover, this study quantified the demand for new challenges to water resources from 2000 to 2016, and then evaluated their impact on water resources and food security in Northwest China. The results showed that in 2000–2016, population growth caused the food consumption WF to increase from 153.8 Gm³ to 159.6 Gm³, with an average annual growth rate of 0.4%. The ratio of per capita consumption of WF of urban residents to rural areas has increased from 80.3% to 120%. The per capita food consumption in the region increased by 1.3% annually due to changes in dietary structure. However, with the increase of water use efficiency, the WF decreased by 0.3% per year. Among them, the total consumption WF of food rations decreased by 51.9%, with an average annual decrease of 4.4%, and that of meat, dairy products and aquatic products increased by 2.4%, 10.8% and 3.0% per year, respectively. From the economic point of view, the development of the energy industry has increased the competition index of energy-grain to water resources from 0.22 to 0.49. Due to climate change, although the precipitation increased at a rate of 3.2 mm/yr, the increase in ET₀ was 3.3 mm/yr, and thus the demand for water resources in agricultural production increased. Based on the results, this paper suggests to carry out measures such as optimizes crop planting structure, adopts effective biological, agricultural technologies, guides healthy food consumption structure, strengthens international food trade and biofuel use and so on to reduce the WF of grain crops and energy industry. Ultimately, the goal of reducing regional water stress and ensuring food security is achieved.