Cross-sectoral urban energy–water–land nexus framework within a multiscale economy: The case of Chinese megacities

Energy, water, and land (EWL) are finite critical resources that should be appropriately managed for sustainable urban development. They are intertwined with each other in the urban system. Previous studies lacked a general framework and a deeply cross-sectoral analysis that simultaneously considered all the sectors within the urban economic system of multiple resources. This study introduced an urban ternary multidimensional nexus (UTMDN) framework for modelling complex urban EWL nexus, connecting in- and trans-boundary interactions by the environmental extended multiscale input–output (EE-MSIO) model. We applied this approach to a comparative study of four Chinese megacities in different economic sectors. Results showed that the top-consuming sectors were heterogeneous on EWL and that the impacts of urban consumption-oriented behaviour extended beyond the urban boundaries. In particular, the sectors of construction, electricity, gas & water, and others were the main consumption-based energy consumers. The agriculture and food sectors were the major consumption-based water and land consumers. These sectors mostly relied on domestic imports for the four megacities. By contrast, Chongqing's embodied water and land flows in the agriculture sector relied more on local (in-boundary) supply. The obtained results proved that this framework could constitute a solid foundation for assessing the cross-sectoral, in- and trans-boundary EWL nexus of critical sectors centred on cities. These sectoral-based analyses can support industrial restructuring and collaborative management of EWL resources for future urban development plans.