Cross-boundary environmental effects of urban household metabolism based on an urban spatial conceptual framework: a comparative case of Xiamen

Abstract

The cross-boundary environmental effects of urban household metabolism are of increasing interest in the context of global climate change and the sustainability of urban systems. To assess resource exchanges and environmental emissions, urban household metabolism was investigated using an ‘emergy synthesis framework’, with the city of Xiamen providing case study data. Two data sets, one from the highly urbanized Xiamen Island (XI) and the other from the less urbanized Xiamen Mainland (XM), were collected and analyzed using an ‘urban spatial conceptual framework’. Household consumption and its spatial environmental effects are embodied by exchanges of resources, energy, services, and wastes between the urban system's physical footprint (‘Urban Sprawl Region’, USR), and its ecological footprint (‘Urban Footprint Region’, UFR). The results show that Xiamen's USR is connected to its UFRs by approximately 98.74% emergy flows. The distinct emergy indicators identified within the results show that the driving forces, processes, influences, efficiency and sustainability of household metabolism vary dramatically between XI and XM, demonstrating that different urban and social contexts significantly affect household metabolism. The Emergy Sustainability Index reveals that USR households need to make lifestyles changes to sustain development. The employed frameworks (urban spatial conceptual framework and emergy synthesis framework) enable the computation of household consumption and cross-boundary environmental effects. The results may help foster alternative household consumption strategies which could result in more equitable resource allocation and effective mitigation of cross-boundary environmental influences.