Sustainability evaluation of the provincial water-energy-food nexus in China: Evolutions, obstacles, and response strategies

Quantifying progress toward the water-energy-food nexus sustainability is essential to promote resource management and sustainable development goals (SDGs). However, systematic studies that are at sub-national scales and consider explicit nexus indicators are lacking. Therefore, we establish a scientific evaluation system under the pressure-state-response framework. We then adopt an improved TOPSIS and obstacle degree model to evaluate the spatial-temporal evolution and obstacles of China's provincial water-energy-food nexus sustainability index (WEFNI), and analyze related trade-offs and response strategies. The results show that the national WEFNI improved in 2008-2018, primarily because of WEF's sustainable utilization state, and response subsystem rapidly turning from a shortcoming to a driving force. There is obvious spatial-temporal heterogeneity in provincial WEFNI, but the regional gap is narrowing. The main obstacles in most provinces are from the pressure subsystem (mainly population and economic growth, and proportion of agricultural water and coal consumption) and the response subsystem (mainly proportion of tertiary industry investment and R&D expenditure). Other obstacles have obvious regional heterogeneity, for example, the low proportion of renewable electricity in major power-generating provinces. Finally, provinces with lower WEFNI are more likely to face the trade-off dilemma; exploring the synergies of response strategies can help reduce trade-offs and improve WEFNI.