With rapid urban expansion and economic development, water shortages and high energy emissions at the regional scale pose critical challenges for urban agglomerations, resulting in quite intricate water-energy nexus. Although important, an assessment framework that can analyze interregional and intersectoral water-energy nexus among cities at the urban agglomeration scale is still lacking. Based on an environmentally extended multiregional input-output model and the concepts of virtual water and embodied energy, this study developed a new assessment framework for the water-energy nexus. By jointly considering the efficiency of input resources and the connections of interregional industrial sectors, this framework can be used to identify the key regions and sectors for water and energy saving. Using the Beijing-Tianjin-Hebei urban agglomeration as an example, the new framework revealed that electricity, gas and water supply industry in Zhangjiakou was a typical high water consumption-high energy consumption sector. Light industry and construction belong to a strong water-energy connection sector, whereas the water-saving measures only partially focus on reducing water consumption but promote energy consumption. In the future, it is imperative to improve the water-energy utilization efficiency of upstream sectors and promote the concept of green buildings with low environmental impacts. The developed framework can be further extended to capture food-energy-water nexus from regional to global scale, and can be used as an important toolbox to pinpoint the sector to realize the sustainable development goals of "clean water and sanitation" (SDG6) and "affordable and clean energy" (SDG7).

Water-energy nexus within urban agglomeration: An assessment framework combining the multiregional input-output model, virtual water, and embodied energy

Economic and resource and environmental carrying capacity trade-off analysis in the Haihe River basin in China

Land–sea ecological connectivity refers to the interaction (convenience or hindrance) of certain physical, chemical and biological processes between terrestrial and marine ecosystems. Research on land–sea ecological connectivity can provide important scientific bases for the conservation and restoration of biodiversity and ecosystems in terrestrial and coastal areas. On the basis of a literature summary of ecological connectivity, this paper focuses on the following: (1) summarizing basic concepts, representative phenomena on multiple spatiotemporal scales, and analysis methods of land–sea ecological connectivity; (2) discussion of the applications of land–sea ecological connectivity; (3) discussion of the relationship between human activities and land–sea ecological connectivity; (4) presentation of perspectives and recommendations on ecological restoration, protection, and biodiversity research, with emphasis on the principle of land–sea ecological connectivity. On the whole, we believe such connectivity in a region varies with changes in multiple physical and artificial factors, such as climate, land cover, biotic community and human activities. Human activities such as land use, engineering construction, urbanization and industrialization have continuously increased and cause irreversible disturbance and destruction of land–sea ecological connectivity, thereby threatening biodiversity and ecosystem services at various spatiotemporal scales. Hence, achievements of theoretical research and practical experience in ecological connectivity should be fully applied in coastal areas to maintain and restore land–sea ecological connectivity and remedy various problems that arise from the blockage and damage of ecosystem services.

Ecological connectivity between land and sea: a review

Sustainable urban resource management depends essentially on a sound understanding of a city's resource flows. One established method for analyzing the urban metabolism (UM) is the Eurostat material flow analysis (MFA). However, for a comprehensive assessment of the UM, this method has its limitations. It does not account for all relevant resource flows, such as locally sourced resources, and it does not differentiate between flows that are associated with the city's resource consumption and resources that only pass through the city. This research sought to gain insights into the UM of Amsterdam by performing an MFA employing the Eurostat method. Modifications to that method were made to enhance its performance for comprehensive UM analyses. A case study of Amsterdam for the year 2012 was conducted and the results of the Eurostat and the modified Eurostat method were compared. The results show that Amsterdam's metabolism is dominated by water flows and by port-related throughput of fossil fuels. The modified Eurostat method provides a deeper understanding of the UM than the urban Eurostat MFA attributed to three major benefits of the proposed modifications. First, the MFA presents a more complete image of the flows in the UM. Second, the modified resource classification presents findings in more detail. Third, explicating throughput flows yields a much-improved insight into the nature of a city's imports, exports, and stock. Overall, these advancements provide a deeper understanding of the UM and make the MFA method more useful for sustainable urban resource management.

Enhanced Performance of the Eurostat Method for Comprehensive Assessment of Urban Metabolism

As land resources and ecosystems provide necessary materials and conditions for human development, land use change and ecological security play increasingly important roles in sustainable development. This study aims to reveal the mutual-influence and interaction between land use change and ecological security in Wuhan, based on the coupling coordination degree model. As such, it provides strategies for the achievement of the synchronous and coordinated development of urbanization and ecological security. The results showed that, during the period from 2006 to 2012, the size of built-up area in Wuhan increased to 26.16%, and that all the other types of land use reduced due to the urbanization process, which appeared to be the main driving force of land use change. The ecological security in Wuhan has been improving as a whole although it was somewhat held back from 2006 to 2008 due to the rapid growth of built-up area. The coupling coordination analysis revealed that the relationship between built-up area and ecological security was more coordinated after 2008. The results can provide feasible recommendations for land use management and environmental protection from the viewpoint of coordinated development. To achieve sustainable development from economic and ecological perspective, policy makers should control the rate of urban expansion and exert more effort on intensive land use, clean energy development and emission reduction.

https://www.mdpi.com/1660-4601/14/11/1435/pdf

陈彬 Chen Bin

Papers

Impacts of mangrove vegetation on macro-benthic faunal communities

Urban metabolism process based on emergy synthesis: Theory and method

Urban metabolism process based on emergy synthesis: a case study of Beijing

Virtual water analysis for the Jing-Jin-Ji region based on multiregional input-output model

Progress and prospects of coastal ecological connectivity studies