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1. Introduction
The success of reducing GHG emissions depends greatly on the policies making at urban, domestic and international scales [1]. The international and domestic governments have established general policies (e.g., United Nations Climate Change Conference and China’s 12th Five-Year Plan) [2, 3], but the policies enforced at the local level need to be improved by adding more detailed emission pictures within its own territory. Cities contribute 67% to the global GHG emissions from fossil energy use [4], so it is essential and urgent to implement reduction plans at the urban scale. As a result, this paper focuses on local energy inputs and GHG emissions in urban regions to guide environment and energy policies making at the substate level.
Many efforts have been made to calculate environmental emissions at the urban scale [1, 6–8], but most of them about urban carbon emissions just focus on the end-use emissions originated from industrial process, transportation, waste treatment, and so on [9–13], ignoring a deeper understanding of the total emissions in terms of both direct and indirect emissions caused by local commodities’ production processes. In fact, all of the commodities consumed in cities lead to GHG emissions during their production processes [8]. For example, the water supply must base on the construction and operation of water works, from which intermediate inputs of steel, concrete, electricity, and so forth are consumed and indirect GHG emissions are produced. As a result, urban planning should consider GHG emissions embodied in commodities used as intermediate inputs to produce products or commodities consumed in cities, not just these obvious direct GHG emissions [5, 14].
To track both direct and indirect effects on embodiments for economies as socioecological systems, input-output analysis (IOA) [15–18] has been applied to analyze embodied GHG emissions [5, 8, 14], energy [19, 20], water resources [21–23], and so forth at urban, domestic, and international scales. Previous input-output studies usually discuss the total emissions (including local and imported emissions) under the assumption that imported commodities have the same embodied intensities as locally produced ones due to the lack of data, which...