China’s Input-Output Efficiency of Water-Energy-Food Nexus Based on the Data Envelopment Analysis (DEA) Model

An explanation and quantification of the water-energy-food nexus (WEF-Nexus) is important to advance our understanding of regional resource management, which is presently in its infant stage. Evaluation of the current states, interconnections, and trends of WEF-Nexus, in cities, has largely been ignored due to quantification hurdles and the lack of available data. Based on the interaction of WEF-Nexus with population system, economic system, and environmental system, this paper builds the input output index system at the city level. Using the input output index system, we evaluate the WEF-Nexus input-output efficiency with the data envelopment analysis (DEA) model. We regard the decision making unit as a "black box", to explore the states and trends of WEF-Nexus. In the empirical study based on data from China, we compare the input-output efficiency of WEF-Nexus in 30 provinces across China, from 2005 to 2014, to better understand their statues and trends of the input-output efficiency holistically. Together with the Malmquist index, factors leading to regional differences in the fluctuation of input-output efficiency are explored. Finally, we conclude that the DEA model indicates the regional consumption of WEF resources in the horizontal dimension and the trends in vertical dimension, together with the Malmquist index, to explain the variations for proposing specific implications.