Assessment on the features of coupling interaction of the food-energy-water nexus in China

Food, energy and water are critical resources for human well-being. A prerequisite for achieving the sustainable utilization of these resources is how to identify and manage the synergies and trade-offs within the food-energy-water (FEW) nexus. This study considered multiple combinations of dimensions, including economic benefits, social benefits and negative environmental impacts, to assess the performance of China’s FEW nexus system. The efficiency of the FEW nexus from 2005 to 2017 was evaluated in 30 provinces across China using a multiplicative environmental data envelopment analysis (ME-DEA) model. The coupling interaction among the FEW nexus was investigated from the perspectives of the coupling degree and coupling coordination degree. Finally, five efficiency bundles of the FEW nexus were identified using the K-means clustering method. Our results showed that 78% of the provinces with high- and sub-high efficiency were distributed in eastern and central China. Conversely, 86% of the low-efficiency provinces were concentrated in western China. Additionally, the coupling coordination degree of most provinces (63%) generally decreased from 2005 to 2017. These results revealed irreconcilable trade-offs among the subsystems of the FEW nexus. Some valuable suggestions for the sustainable use of resources were proposed according to the characteristics of the five efficiency classes. Class 1 performed well in the water, food and labor dimensions. To balance the FEW nexus, we recommend adjusting energy-related policies. Class 2 showed inefficiency in all dimensions, particularly for labor and social efficiencies. Therefore, the government should provide more employment opportunities and improve social benefits for households. A gap in economic efficiency was found in Class 3. Thus, policies and funding support for the economic dimension are recommended. Class 4 had lower efficiency values than the average, particularly in terms of energy and environmental aspects. The government should pay more attention to pollution treatment. For Class 5, synergies were found in all partial efficiencies; thus, the current development strategies should be adhered. These findings are helpful for developing policies that enhance the sustainability of the FEW nexus.