Safety evaluation of water-energy-food coupling system in Beijing-Tianjin-Hebei region

In order to realize the water-energy-food cooperation in the Beijing-Tianjin-Hebei region, 31 indicators were selected to construct a safety index system for water-energy-food coupling system from reliability, synergy and resilience. The security level of water-energy-food coupling system in the Beijing-Tianjin-Hebei region from 2000 to 2020 was analyzed, and the joint risk probability was calculated based on Copula function. The results show that the security index of water-energy-food coupling system in the Beijing-Tianjin-Hebei region shows an overall upward trend from 2000 to 2020. The annual average index of Beijing is the highest, reaching 0.63, and that of Hebei is the lowest, only 0.48. There is no significant difference in reliability levels among different regions, and they all exhibit poor levels. The main obstacles influencing the security of the water-energy-food coupling system include per capita water resources, per capita energy consumption, the proportion of groundwater supply, and carbon dioxide emissions. The probability of achieving a relatively safe level of reliability, synergy, and resilience in the Beijing Tianjin Hebei region is 0.723, and uneven development will affect the overall security of the water-energy-food coupling system.