The concept of circular economy (CE) offers an innovative and systematical approach to address a number of urban sustainability issues, via exploring symbiotic ways to design circular urban systems and optimizing the materials and energy metabolism of cities, so as to mitigate environmental footprints. Urban sustainability is highlighted as a critical issue in the Sustainable Development Goals (SDGs) proposed by United Nations; hence, in nature, circular economy could offer a number of solutions towards SDGs in urban scope. As trade-offs, circular economy also potentially causes negative impacts to business-asusual scenario, which is easily to be ignored. To highlight this scientific issue, this paper identified and matched the role of circular economy in realizing 17 SDGs in urban scope. How circular economy strategy could potentially affect the SDGs, whether positive or negative, were comprehensively evaluated. We expect such findings could support an equilibrium decision-making on circular economy promotion in cities, rather than an optimum solution to a single target under the triple bottom line of sustainability.

Due to their characteristics and multiple objectives, high-speed rail (HSR) projects carry more complex risks than conventional projects and high correlation and conductivity are among the associated risk factors. Previous risk assessment frameworks for rail infrastructure have ignored the effects of risk interactions that inflate risk levels, namely, risk coupling effects. Based on a system dynamics method, this paper develops a risk coupling model for HSR project risk assessments. A risk factor list is established from a literature review, and relationships analysed using a case study and expert interviews. System dynamics equations are constructed and their parameters obtained by expert evaluations of risk factors. The proposed model is applied to a real-world HSR project to demonstrate it in detail. The model can evaluate the risk levels of HSR projects during a simulation period. In particular, it can identify the key coupling effects that are the main increased risk. It provides a significant resource, using which HSR project managers can identify and mitigate risks.

Mega infrastructure projects (MIPs) have become increasingly important to the realization of sustainable development in China. Sustainable development is a process of dynamic balance, and coordinating the triple bottom line (the environmental, social, and economic dimensions) will enable more sustainable development of MIPs. However, previous studies have lacked consideration of coordination when applying sustainable development principles to the systematic identification of risks to MIPs. The goals of this study were to clarify the definition and dimensions of the sustainable development of MIPs and to identify the key risks of MIPs. A literature review was performed to extend the definition of sustainable development of MIPs by combining the triple bottom line with a fourth coordination dimension. A conceptual model of MIP risk identification was then proposed from an extended sustainable development perspective, 22 sustainability elements and 75 risk factors were identified, and the key risk factors were determined based on the interview responses and fuzzy set theory. The results show that economic risks have a high probability, social risks have a high loss, environmental risks have an intermediate probability and loss, and coordination risks have the greatest impact. In addition, the three most important key risk factors were found to be construction and installation cost overruns, land acquisition and resettling cost overruns, and information sharing with the public. Identifying key risk factors can provide information to help stakeholders understand the risk factors associated with MIPs and formulate reasonable risk response strategies.

Urban-industrial symbiosis (UIS) is an important system innovation via sectors integration, and has been widely recognized as a novel pathway for achieving regional eco-industrial development. Eco-efficiency, as a mature approach and indicator, offers an effective tool to uncover both the status and trends of such a transformation. However, most studies have focused on the whole industry or city as a whole, which has meant that a view from the sectoral level focusing on UIS was missing. To fill this research gap, this paper applied a modified eco-efficiency approach using integrating input–output analysis (IOA) and carbon footprint (CFP) to identify the eco-efficiency benefits of UIS from a sectoral level. Specifically, sector-level economic data (as economic outputs) and CFP (as environmental impacts) are used to calculate the sectoral eco-efficiency. IOA helps to offer sectoral economic data, and, with integrating process-based inventory analysis, to conduct a CFP calculation at the sectoral level. To test the feasibility of the developed approach, urban industrial symbiosis scenarios in one typical industrial city of China were analyzed. This city is held up as the national pilot of the circular economy, low-carbon city, and ecological civilization in China. Scenarios analysis on a business as usual (no UIS) and with UIS implementation in 2012 were undertaken and compared with the change of sectoral CFP and eco-efficiency. The results highlighted a moderate increase in eco-efficiency and trade-offs in certain sectors, indicating that UIS was moderately effective in increasing the urban resource efficiency from a sectoral level, but a refined design was required. Policy recommendations are made based on the analytical results, to inform decision makers and urban and industrial managers seeking to improve the implementation of UIS as a means of achieving greater urban sustainability.

Along with unprecedented urbanization in the last few decades, cities have experienced rapid social and economic transformation in China. A major challenge facing urban authorities in the immediate future is how to plan and govern cities such that they can serve as inclusive systems where everyone is enabled and empowered to fully participate in and contribute to socioeconomic life. A first step towards realizing this is to conceptualize an integrated framework that allows analysts and decision-makers to delineate, evaluate, and guide the development of these cities towards inclusiveness. In this study, we conducted a conceptual analysis of urban inclusiveness and then proposed a multidimensional framework for the evaluation of inclusive development. This is followed by the presentation of the case of Xiong’an, for which inclusive development indicators (IDIs) were selected. By comparing the state before the establishment of Xiong’an with its current development progress, and analyzing the area’s management structure and policy measures, the inclusive development challenges are identified. Subsequently, suggestions are given on how to direct Xiong’an toward higher levels of inclusiveness, including offering equal access to public services and employment opportunities, preserving environmental health and sustainable use of natural resources through waste recycling, and encouraging public participation in decision-making to bring higher levels of inclusion within reach.