Unveiling the water-energy-food nexus efficiency and influencing factors in China: An integrated EBM and Tobit model analysis

• Epsilon-based measure model evaluated efficiency with undesirable output. • Water subsystem constrained water-energy-food nexus system efficiency improvement. • Temporal and spatial characteristics of system efficiency were analyzed. • Per capita arable land was identified as a key driver of system efficiency. The rising demand for water, energy, and food has intensified resource constraints and environmental challenges, making the efficient use of resources a curcial strategic necessity. This research established an Epsilon-Based Measure (EBM) model considering undesired outputs to investigate the water-energy-food nexus (WEFN) system efficiency in China from 2011 to 2022. Additionally, a Tobit regression model was applied to ascertain the key factors influencing efficiency. Results reveal that: (1) China’s WEFN system efficiency exhibits a fluctuating pattern in which the water subsystem is the limiting factor. (2) The inter-provincial WEFN system’s efficiency has notable spatial differences, with the eastern region outperforming the central and western regions. (3) There is significant spatial agglomeration between regions, with high-high (H-H) clusters predominantly in the Beijing-Tianjin-Hebei area, whereas low-low (L-L) clusters are primarily located in central and western provinces. (4) From the perspectives of both geographic location and efficiency distribution, per capita arable land (PCA) has been identified as a critical factor affecting the WEFN system efficiency. In conclusion, facilitating the rational use of resources and limiting pollution are effective measures to optimize the efficiency of the WEFN system and foster high-quality development in the region.