Exploring urban energy-water nexus embodied in domestic and international trade: A case of Shanghai

Rapid urban expansion and economic development has led to severe demands of energy and water resources, which poses serious challenges to sustainability and environment. Previous studies have taken more consideration of one resource flow ignoring the interconnectedness between energy and water. In this paper, an urban energy-water nexus framework is constructed considering both domestic and international trade, based on the environmentally extended multi-scale input-output (EE-MSIO) model. This method allows us to trace energy and water flows in a multi-scale economic system from production and consumption perspectives. In basis of that, the nexus strengthen indicator is constructed to evaluate the energy-water nexus of the trading regions with Shanghai city in the domestic and international trade to present the integrated environmental pressure externalized in Shanghai’s rapid economic development. Findings indicate that Shanghai is a net importer of energy and water flow. This result is compatible with the fact that Shanghai is a consumer city. Additionally, the seven domestic regions in China are net exporters toward Shanghai, supporting around 55.10% of energy and 70.56% of water import flows driven by city’s final demand. Shanghai largely imports flows of energy and water from Mainland China and developing regions across the globe, whereas export little to developed nations. Nexus results indicate that from consumption perspective, Hebei and Shandong are of the highest nexus strength embodied in domestic trade with Shanghai, with nearly equal contribution for both energy and water. While USA is the largest energy-water nexus node embodied in international trade with Shanghai, around 60% energy and 40% water contributed to the nexus. During these tradeoffs, Shanghai is the major beneficiary, being able to externalize environmental pressures by consumption of domestic and international exported goods and services. The study outcomes suggest that a higher coordination, together with a rearrangement of the regional trade structure, should be the key leverages for an effective management of resources and environment.