城市代谢效率研究的热点识别与综合效率实证研究

Abstract

城市代谢是城市可持续发展研究的重要部分，其有序运行为城市发展与居民生活提供重要保障，代谢效率的提高有助于缓解资源利用与环境保护间的矛盾。通过分析国内外近30年的城市代谢效率的研究进展，整合代谢效率研究热点选取综合效率评估所需指标，并以深圳市为案例研究，结合数据包络分析（DEA）模型对城市物质代谢综合效率进行评估。结果表明：（1）近30年城市代谢研究处于蓬勃发展阶段，中国在相关研究领域中的影响力凸显，而城市代谢效率研究主要关注能源、水资源、碳氮元素及耐用物质（主要为建筑材料）等要素及其环境效应；（2）基于上述要素对深圳城市代谢的综合效率进行评估，其综合效率在2005-2017年间呈波动状态，多数年份城市代谢过程取得了高效运行（效率值大于1），但仍存低效年份，包括2006（0.96）、2007（0.76）、2011（0.85）和2013（0.97）年，研究期间综合效率提高不明显。在资源投入与效益产出方面，深圳市在水资源利用效率方面需进一步提高；在当前资源消耗水平下经济效益仍有提高潜力；在减少碳氮元素的环境排放及建筑垃圾产生的效率方面有一定程度的提高。（3）通过城市代谢效率研究的热点识别，可明晰目前城市代谢综合效率评估所需涵盖的要素，由此建立评估体系可用于综合效率评估的实践，通过案例分析研究其反映城市资源利用效率动态的可行性，以期为城市可持续发展评估提供科学参考。;Urban metabolism is long-term regarded as a hot topic in the research field of urban sustainability, and it's well-running provides an important guarantee for urban development and residents' livelihood. The improvement in metabolic efficiency helps to alleviate the contradictions of urban resource utilization and environmental protection. This research firstly analyzed the worldwide progresses in the research of urban metabolic efficiency over past 30 years, and then summarized the research hotspots of metabolic efficiency accompanied with indicators selection for integrated efficiency evaluation. Take the populous Shenzhen city in China as case study, which is regarded as the hotspots for urban metabolism research, and the Data Envelopment Analysis (DEA) model was adopted to evaluate the integrated efficiency of urban metabolism. The results showed that: (1) The booming in urban metabolism research were emerging in the past 30 years, which contributed most by China, especially in 2011-2020, followed by America, England and Italy. Research on urban metabolic efficiency mainly focused on the urban metabolism of energy, water resources, carbon element, nitrogen element and durable substances (mainly building materials) and their environmental effects. (2) Based on the evaluation of the integrated efficiency concerning above factors, the integrated efficiency of Shenzhen's urban metabolism presented fluctuated. In most years, the urban metabolic processes have achieved efficient operations, which were reflected by efficiency value >1, but there still existed inefficient years, including 2006 (efficiency value=0.96), 2007 (efficiency value=0.76), 2011 (efficiency value=0.85) and 2013 (efficiency value=0.97), and the integrated efficiency of urban metabolism in Shenzhen has not been significantly improved during the study period. In terms of the benefit outputs from the process of resource inputs, the utilization efficiency of water resource in Shenzhen still needs to be improved. Based on current level of resource consumption, it is potential for Shenzhen to further rise economic benefits. However, the efficiencies of reductions in carbon and nitrogen emissions, as well as construction wastes, have been improved to a certain extent during study period. (3) Hotspots identification in the research of urban metabolism efficiency can clear elements of urban metabolism for the integrated efficiency evaluation, which contributes to the practical of integrated efficiency evaluation with the established evaluation system. The case study showed that the feasibility of integrated efficiency evaluation of urban metabolism to reveal the dynamic in overall resources use efficiency in a city, aiming at providing scientific reference for the assessment of urban sustainability towards national sustainable development.