Mapping Water, Energy and Carbon Footprints Along Urban Agglomeration Supply Chains

China's urban population will increase by 268 million from 2010 to 2030, with the consumption of a large number of resource-intensive products. Quantitative analysis of the environmental impacts (water, energy and carbon) of urban agglomerations can make trade-offs among water conservation, energy use, climate change mitigation, and urban development. In this study, a multi-layer water-energy-carbon production path analysis (MWPPA) model is developed for identifying the key final demands, sectors and supply chain paths of the Pearl River Delta urban agglomeration (PUA). Results show that, water, energy and carbon-emission intensities respectively reduced by 27.3%, 35.6% and 27.6% in 2015, compared to the levels in 2012. More than half of the water-energy-carbon (WEC) footprints are export-driven, where Guangzhou, Shenzhen and Foshan dominate the WEC footprints of PUA. Results also disclose that Shenzhen is the main recipient of water-energy, while Jiangmen and Huizhou are the main providers of water and energy, respectively. Policy makers are suggested that each industry actively integrate into global value chains in order to leverage its comparative advantage, and Huizhou should take full advantage of its fossil base to form a complete industry chain from the R&D end to the production end around the energy industry.