Spatio-temporal evaluation of the water-energy-food nexus system risk from a provincial perspective: a case study in China

This study first defined the concept of the water-energy-food nexus system risk (WEF-R). Then, the WEF-R evaluation index system was established from three aspects: stability, coordination, and sustainability subsystems. Finally, the set pair analysis-variable fuzzy set model was used to evaluate the risk levels of subsystems, and the risk matrix was applied to assess provincial WEF-R levels in China from 2009 to 2018. The results showed that the stability subsystem had the greatest influence on provincial WEF-R, followed by the sustainability subsystem. The provinces with a higher risk of the stability subsystem and lower risk of the sustainability subsystem were mainly centralized in southeast coastal and central regions, which were consistent with the provinces with better socio-economic development. The provinces with lower risk of the stability subsystem and higher risk of the sustainability subsystem were mainly concentrated in northwest regions, which correspond with the provinces with better natural resources endowment but lower socio-economic development. As for the temporal evolution of risk levels, the risk levels of the coordination and sustainability subsystems showed downward trends during the study period, while the risk level of the stability subsystem displayed a small fluctuation, and the provincial WEF-R level in China presented a decreasing trend.