Typifying cities to streamline the selection of relevant environmental sustainability indicators for urban water supply and sewage handling systems: a recommendation

Measuring performance and setting targets and benchmarks for the future entail the adoption of metrics or indicators. Sustainability is a multi-pronged objective encompassing social, economic, health, cultural, governance and environmental aspects. Indicators can be grouped under these categories. The selection of environmental sustainability indicators for a water and wastewater utility in a city needs to be based on concerns specific to the utility in question. The authors, in this paper, have recommended the classification of cities into city types based on specific attributes and identification of relevant environmental sustainability indicators, from a pool of 13 indicators, for these different city types. Having selected the relevant indicators, utilities can use them as tools to improve their environmental performance. The purpose is to not facilitate inter-utility comparisons within or across city types. Every utility would compare its environmental performance at a given point in time with what it was in the past. Towards the end, the paper also applies the methodology to nine cities across four continents—Europe (Oslo, Trondheim and Turin), Asia (the National Capital Territory of Delhi, Beijing, Tel Aviv and Male), North America (Sacramento) and South America (São Paulo). In all, 13 environmental sustainability indicators have been identified. Two cities—Oslo and Trondheim (both from Norway) belong to the same city type, while the other seven are different from each other in this regard. The number of relevant indicators ranged from 4 for Trondheim to 11 for Tel Aviv. The methodology is not restricted to urban water supply and sewage handling systems. It can be extended to other infrastructure systems as well—waste management, transportation, etc.     

The Role of Foreign Direct Investment in Urban Environmental Management: Some Evidence from Hanoi, Vietnam

In recent years flows of foreign direct investment (FDI) to developing countries have rapidly been increasing. It is now an important contributor to the national economy and urban growth in scores of developing countries. Rapid urbanization in these countries is leading to many problems in the cities. Existing urban infrastructure and municipal services have been unable to cope with the increased demand arising from growing population and rapid economic growth. Consequently, the environment in these cities has deteriorated alarmingly. This paper assesses the role of FDI in urban environmental management (UEM) by analyzing the linkages between them for Hanoi City in Vietnam. The paper's analysis and findings are presented under three main themes: one, FDI, employment and income; two, FDI and environmental degradation; and three, potential of utilizing FDI for the provision of urban environmental infrastructure and services (UEI&S) in order to improve the urban environment. Both primary and secondary source data have been used. Policy implications of the research findings are drawn from the perspective of sustainable development.     

长江三角洲城市群发展研究

概观当代城市发展的趋势，全球化促进了全球城市发展，区域化正在形成巨型城市区域，地方化使城市集群各具特色。长江三角洲城镇群在国家具有特别重要的地位与作用，也是中国融入全球化进程首要的全球区和全球城市形成地区。长江三角洲城镇空间布局应该顺应这些潮流，发展全球城市，建设巨型城市区，组建网络城市，规划走廊城市。     

交通网络建设与成渝城市群一体化发展——基于交通设施网络和需求网络的分析

交通基础设施建设是城市群一体化发展基本内容和重要保障。以成渝城市群为研究案例，利用复杂网络分析方法，探讨了交通设施网络和交通需求网络下城市群一体化格局，并分析了交通基础设施建设对城市群一体化的影响。结果表明：（1)交通基础设施建设拓展了城市间的联系渠道，有助于形成多中心、均衡化的交通设施网络格局，并塑造城市带和城镇密集区的雏形。（2)以客流衡量的交通需求网络依然呈现以成都和重庆主城为中心的双核心格局，多中心态势并不显著，但高铁的开通增强了城市客流网络。（3)交通设施网络的完善推动了成渝城市群形式一体化，但人口流动、产业合作等表现出的功能一体化水平依然偏低。因此，未来成渝城市群在完善区域交通运输系统的同时需要探索以交通促进城际人口流动、产业合作、城乡统筹等的发展路径，以交通网络建设带动城市群空间结构的优化调整，最终实现区域深度一体化。     

基于等级-网络分析框架的泛长江三角洲中心城市评价研究

城市中心性既体现在城市的等级位序，亦表现为城市在网络体系中的节点连通性以及节点之间的“流”强度。将区域城市等级体系和关系网络研究相结合，是城市体系理论与实践研究可探索的方向。以泛长江三角洲52个城市为研究对象，通过中心城市指数表征城市的等级中心性，企业网络联系测度城市的网络中心性，结合城市的等级中心性和网络中心性特征进行中心城市评价。将泛长江三角洲地区中心城市划分为了5个等级和7种类型，分别是：1个全球城市:上海；3个国家中心城市:杭州、南京、苏州；温州等6个区域等级中心城市；宁波等8个区域网络枢纽城市；盐城等8个地区等级中心城市；淮北等6个地区网络枢纽城市以及19个地方一般城市。基于对中心城市的类型划分，可进一步研究提出针对不同类型城市的分类引导政策。通过提升基础设施连通度、延伸产业链等措施来提升等级中心性较高城市的系统开放性；通过强化要素资源集聚，提高城市服务水平等促进关系网络枢纽城市的等级水平。 关键词： 中心城市；等级体系；关系网络；泛长江三角洲     

Socio-environmental consideration of phosphorus flows in the urban sanitation chain of contrasting cities

Understanding how cities can transform organic waste into a valuable resource is critical to urban sustainability. The capture and recycling of phosphorus (P), and other essential nutrients, from human excreta is particularly important as an alternative organic fertilizer source for agriculture. However, the complex set of socio-environmental factors influencing urban human excreta management is not yet sufficiently integrated into sustainable P research. Here, we synthesize information about the pathways P can take through urban sanitation systems along with barriers and facilitators to P recycling across cities. We examine five case study cities by using a sanitation chains approach: Accra, Ghana; Buenos Aires, Argentina; Beijing, China; Baltimore, USA; and London, England. Our cross-city comparison shows that London and Baltimore recycle a larger percentage of P from human excreta back to agricultural lands than other cities, and that there is a large diversity in socio-environmental factors that affect the patterns of recycling observed across cities. Our research highlights conditions that may be “necessary but not sufficient” for P recycling, including access to capital resources. Path dependencies of large sanitation infrastructure investments in the Global North contrast with rapidly urbanizing cities in the Global South, which present opportunities for alternative sanitation development pathways. Understanding such city-specific social and environmental barriers to P recycling options could help address multiple interacting societal objectives related to sanitation and provide options for satisfying global agricultural nutrient demand.

     

土地开发对城市经济增长的作用机制和传导路径——基于结构方程模型的实证检验

已有文献对土地开发、土地收入与城市经济增长间的关系进行了大量探讨,但未能揭示土地开发对城市经济增长的作用机制和传导路径,尤其是没有区分土地开发对城市经济增长的直接和间接影响,直接影响主要是土地开发收入用于城市基础设施建设带来的投资效应,间接影响包括土地开发收入通过改善城市基础设施和公共服务、增强对产业和人口的吸引力对城市经济增长的促进作用。本文构建了反映土地收入对城市经济增长的作用机制和传导路径的结构方程模型,利用285个城市2000—2010年以及2011—2013年的差分数据进行了实证检验。结果表明:土地开发收入显著促进了城市经济增长。2000—2010年间,土地出让收入每增长1个标准单位,城区GDP将增长3.09标准单位,其中土地开发收入的直接影响为0.35标准单位,间接影响为2.74标准单位。土地开发通过改善城市基础设施和公共服务、增强对产业集聚和常住人口吸引力的间接效应远大于用于城市基础设施建设投资的直接效应,在间接效应中,吸引产业集聚的影响大于吸引常住人口的影响。不同类型城市土地开发收入对城市GDP的直接影响和间接影响的程度不同。     

Quantifying and managing food-sourced nutrient metabolism in Chinese cities

Food supply and consumption are critical for sustaining urban system functions, and are key determinants of the quantity and pathways of nutrient flow in cities. Nutrient elements from urban food consumption are becoming major pollutant sources in urban environments. Therefore, understanding flow magnitude and pathways, the role of a growing population, and changing dietary structure and technology in future nutrient metabolism are essential to understand cities as ecosystems and urban environmental management. Taking the city of Xiamen, a rapid urbanizing area of Southeast China as a case study, we simulated urban metabolism of three major food-sourced nutrient elements (carbon, nitrogen, and phosphorus or CNP) over 1991–2010 and environmental emissions. Impacts of future population growth, dietary habit change, and waste treatment improvement on various environments were forecast by scenario analysis. A sensitivity analysis was conducted to test how different waste treatment technologies affect environmental emissions from food-sourced nutrients. Our results show that the food-sourced CNP had various metabolic fluxes through urban systems, with carbon mostly emitted into the air and nitrogen and phosphorus mostly discharged into landfills and water. Population growth and dietary structure change will accelerate increases of nutrient emissions to the environment, whereas enhancing current waste treatment technology can just alter emissions to different environments. Based on the results, we discuss how food-sourced nutrient metabolism can be better managed, to enhance connectivity between cities and their hinterlands and maintain environmental emissions within the carrying capacity of the cities.     

“红三角”地区城镇体系结构分形研究

分形维数是刻画城镇体系结构的有效参数。将“红三角”地区分成韶关、郴州、赣州三个城镇体系，分别测算各个城镇体系的Hausdorff维数、空间关联维数及牛鸦维数比、随机集聚维数。测算结果表明:①赣州、郴州两市的中等位序城市较多，人口分布比较均衡，而韶关市城镇体系等级规模差异明显，人口分布差异程度较大，韶关市区人口规模大，具有较强的垄断性；②各城镇体系中的城镇有集中到某一地理线上的趋势，具有轴线特征，同时整个地区的交通网络比较完善，整体通达性好，但城镇体系空间关联程度不够紧密；③各城镇体系空间分布呈现集聚性特征。最后对“红三角”地区城镇体系建设提出了发展次级中心城镇、加强区域空间结构轴建设、适当调整行政区划和加快交通基础设施建设的建议。     

经济集聚对碳排放强度的影响及传导机制

中国城市群的兴起催生经济集聚,化石能源消耗增多引发碳排放形势愈加严峻,探索经济集聚对碳排放强度的影响及传导机制至关重要。本文以2004-2016年京津冀、长江三角洲、粤港澳大湾区、成渝城市群的61个城市面板数据为研究样本,探索经济集聚与碳排放强度的关系及影响机制,创新性地使用抗日战争时期各城市是否有铁路通过、2003年各城市是否有机场、各城市历年的国家级经济技术开发区数量作为工具变量解决内生性问题,构建中介效应模型分别检验环境规制和城镇化水平对经济集聚影响碳排放强度的传导机制,并分析经济密度异质性下经济集聚对碳排放强度的不同作用路径。结果表明:①经济集聚与碳排放强度之间呈显著的负向关系,现阶段城市经济集聚水平的提高有利于降低碳排放强度;②相对于低经济密度城市,高经济密度城市经济集聚的降碳效果更为明显;③经济集聚不仅直接对碳排放强度产生影响,还通过环境规制与城镇化水平两条路径间接对碳排放强度产生作用,中介效应显著;④低经济密度城市经济集聚对碳排放强度的间接影响主要是通过城镇化水平来传导,而高经济密度城市经济集聚对碳排放强度的间接影响可以靠环境规制和城镇化水平两条路径来实现。据此本文认为,政府应推动城市群经济以促进区域融合发展,实现企业联动合作以提高经济集聚水平。针对经济密度不同的城市治理手段应有所侧重,高经济密度城市应以增强环境规制力度为主要碳减排手段,而低经济密度城市则应通过提高经济集聚水平,改善城市建设水平并最终达到碳减排的目标。     

Governance and networks for health co-benefits of climate change mitigation: Lessons from two Indian cities

Health has been the main driver for many urban environmental interventions, particularly in cases of significant health problems linked to poor urban environmental conditions. This paper examines empirically the links between climate change mitigation and health in urban areas, when health is the main driver for improvements. The paper aims to understand how systems of urban governance can enable or prevent the creation of health outcomes via continuous improvements in the environmental conditions in a city. The research draws on cases from two Indian cities where initiatives were undertaken in different sectors: Surat (waste) and Delhi (transportation). Using the literature on network effectiveness as an analytical framework, the paper compares the cases to identify the possible ways to strengthen the governance and policy making process in the urban system so that each intervention can intentionally realize multiple impacts for both local health and climate change mitigation in the long term as well as factors that may pose a threat to long-term progress and revert back to the previous situation after initial achievements.     

Urbanisation Without Development: Environmental and Health Implications in African Cities

Sustainable development advocates for a balance between socio-economic development and the environment in the pursuit of human advancement. In Africa, high population growth and inadequate infrastructure in urban areas exert pressure on the environment and this threatens the health and wellbeing of urban residents. The population of the African continent until the 1960s was predominantly rural. This scenario has taken a swift turn and some of the major shifts in the global urbanisation process are taking place on the continent. Factors including natural increase in the population, rural–urban migration, strife and hunger leading to the internal displacement of populations have exacerbated the urbanisation process in Africa. The situation has been worsened by the imposition of Western development policies, including structural adjustment programmes on African nations, which has eroded the subsistence base of rural agricultural communities and further ignited rural urban migration. The failure of industry to absorb the increasing labour force has created massive unemployment and deepening poverty crisis in urban centres. Inadequate provision of infrastructure and services to meet the growth in urban populations has resulted in inefficient spatial development of urban centres, the proliferation of squatter settlements, inadequate basic amenities including potable water, sanitation and waste disposal. Poor environmental sanitation has resulted in the upsurge of infectious diseases and deteriorating urban health. Urban populations in Africa are also the worst affected by newly emerging diseases, particularly HIV/AIDS. The poor bear a disproportionately large share of the problems due to their particular vulnerability to environmental and health risks. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Moving towards urban sustainability in Kenya: a framework for integration of environmental,economic, social and governance dimensions

Global urban development is increasingly becoming an aspect of focus as nations fight sustainability challenges. A review of the current literature on urban sustainability suggests that research on development of cities, in both developed and developing countries, is growing fast, with an emphasis on sustainable development. However, very little of this research contains an integrated framework to systematically identify and examine the various dimensions of urban sustainability and to measure and evaluate them appropriately. Cities are more than the sum of their sectors, and are complex and interdependent systems on whose dynamics the quality of life of millions of human beings and a good part of the economy depend. Environmental, economic, social and governance problems can create formidable barriers to urban sustainability. Governance remains a critically important dimension of urban sustainability, especially when discussing urbanization in developing countries, given rapid population movements and imbalances in socio-economic development. Understanding how cities function is fundamental to resolving these imbalances. The aim of this paper is to provide a review and analysis of the concept of urban sustainability and to propose the development of a holistic framework through integration of environmental, economic, social, and governance dimensions of sustainability. Such a review would make it possible to understand the complex dynamics of the four dimensions and to assess the progress and challenges in moving towards urban sustainability, taking the case of Nairobi, Kenya, as an example. The paper argues that, for urban sustainability in developing countries, more emphasis should be placed on the governance dimension, because this is where the biggest challenge exists, with increasing needs for immediate management of rapid urbanization.     

Adaptive urban governance: new challenges for the second generation of urban adaptation strategies to climate change

The task of adapting cities to the impacts of climate change is of great importance—urban areas are hotspots of high risk given their concentrations of population and infrastructure; their key roles for larger economic, political and social processes; and their inherent instabilities and vulnerabilities. Yet, the discourse on urban climate change adaptation has only recently gained momentum in the political and scientific arena. This paper reviews the recent climate change adaptation strategies of nine selected cities and analyzes them in terms of overall vision and goals, baseline information used, direct and indirect impacts, proposed structural and non-structural measures, and involvement of formal and informal actors. Against this background, adaptation strategies and challenges in two Vietnamese cities are analyzed in detail, namely Ho Chi Minh City and Can Tho. The paper thereby combines a review of formalized city-scale adaptation strategies with an empirical analysis of actual adaptation measures and constraints at household level. By means of this interlinked and comparative analysis approach, the paper explores the achievements, as well as the shortcomings, in current adaptation approaches, and generates core issues and key questions for future initiatives in the four sub-categories of: (1) knowledge, perspectives, uncertainties and key threats; (2) characteristics of concrete adaptation measures and processes; (3) interactions and conflicts between different strategies and measures; (4) limits of adaptation and tipping points. In conclusion, the paper calls for new forms of adaptive urban governance that go beyond the conventional notions of urban (adaptation) planning. The proposed concept underlines the need for a paradigm shift to move from the dominant focus on the adjustment of physical structures towards the improvement of planning tools and governance processes and structures themselves. It addresses in particular the necessity to link different temporal and spatial scales in adaptation strategies, to acknowledge and to mediate between different types of knowledge (expert and local knowledge), and to achieve improved integration of different types of measures, tools and norm systems (in particular between formal and informal approaches).     

基于适度人口容量的生态文明城市建设研究——以广东省惠州市为例

生态文明城市是新型城镇化建设的目标,是实现经济发展、民生改善与生态保护协调统一的最佳方式。适度的人口容量、科学的城市规划和有效的城市治理是避免和减轻城市病的根本途径。本文从生态经济学和系统工程学跨学科的视角出发,构建了一个基于适度人口容量,人口流动和城乡均衡发展的生态文明城市建设路径的理论分析框架,并以广东省惠州市为例,根据土地功能定位和主体功能区定位,分别测算了惠州市的适度人口容量;基于人口自然变动和人口机械变动的趋势,预测了惠州市未来人口发展状况。研究发现,惠州市常住人口已略微超过基于土地功能定位测算的适度人口容量,但基于主体功能定位的人口密度模型测算表明,惠州市未来人口发展规模远低于适度人口容量,进而从总体上剖析了惠州市生态文明城市建设中适度人口容量和人口均衡发展方面带有普遍性的问题和原因。由此,揭示出生态文明城市的创建,必须基于人口承载力,走动态规划调控路子,协同推进经济建设、民生改善、生态保护、环境优化和制度改革,真正地促进流动人口市民化、城乡公共服务均等化和社会保障公平化。     

大城市应对气候变化的可持续发展研究——以上海为例

在全球气候变化背景下,社会城镇规划与自然气候变化之间的关系越发密切,城镇规划体系需要纳入气候变化的影响并考虑适应气候变化的策略。首先以发达国家及世界著名大城市为参考,对美国、德国和日本在应对气候变化的城镇可持续发展规划方面的成功经验和实践措施分别进行了综述和提炼;然后,以上海为例,对照分析了我国大城市在城镇化过程中面临的气候变化挑战及存在的脆弱性,包括城镇发展规划与气候环境的相容性考虑不够、城镇化过程对气候环境的影响缺乏充分论证、城镇基础设施抵御气象灾害的能力较低、气候变化对城镇人体健康的影响未给予高度关注等;最后,指出了我国大城市应对气候变化的城镇可持续发展思路及重点方向,即充分考虑区域气候容量、大力构建生态绿色通风廊道;深入开展城镇功能布局的气候可行性论证和气象灾害风险评估;加强城市气候变化研究和实验,不断更新城市规划设计参数和标准规范;加大对脆弱人群和外来常住人口生命安全和人体健康监测预警;积极完善城镇化适应气候变化的机制等,以期为城镇发展体系的编制和应用提供参考和借鉴。     

长江中游城市群发展质量评价研究

为探究城市群内部城市的质量及城市间的协调关系，通过构建经济发展质量、社会生活发展质量、生态环境质量指标体系，运用动态因子分析方法对长江中游城市群38个城市2004～2011年城市质量进行了评价，运用空间自相关方法分析了城市群内城市之间城市质量的空间溢出效应。研究结果表明：从城市群内城市质量的评价来看，城市群内城市质量差距进一步扩大，产生严重的两级分化；从城市群内城市间的协调来看，长江中游城市群内城市质量的空间影响作用不大，各省份城市发展并没有突破行政壁垒，跨区域的经济社会环境合作未有实质性进展，长江中游城市群目前的发展质量并不高，并提出了加快中小城市建设，推动经济、基础设施、社会事业与公共服务设施一体化建设等提高城市群质量的建议     

长江流域经济发达地区城市发展思路

长江流域具有优越的区位条件和良好的经济基础,改革开放后城市化水平大幅提高,目前该流域的城市格局正处于由传统的封闭型工业生产城市向经济型、开放型和以第三产业为主转变,单体城市也开始向相互依托、相互发展的城市群体转变。本文分析和总结了长江流域城市发展的现状和存在的问题,如城市化滞后于工业化、城市规划同城市发展不相适应、城市建设资金就足和城市生态环境问题等。在此基础上重点对长江中下游地区城市２１世纪发展     

土地出让对长江中游城市群经济辐射的影响效应与形成机制研究

以湖北、湖南、江西3省36个地级以上城市为研究区域,将2003～2016年城市面板数据作为样本,构建扩展的空间杜宾模型,实证检验了土地出让对长江中游城市群经济辐射的影响效应及其形成机制,结果表明:(1)土地出让对长江中游城市群经济辐射带动的促进效应较小,表现为仅有中心城市土地出让对城市群经济辐射具有显著为正的直接空间效应,而非中心城市直接空间效应、中心城市和非中心城市的间接空间效应均不显著;(2)土地出让对长江中游城市群经济辐射的促进作用主要依靠基础设施投资、技术效率和省级财政转移支付机制,而企业投资和劳动力机制的积极效应没有形成。原因是,土地出让对企业投资、劳动力的拉动效应不显著,且企业投资没有显著扩散效应,而劳动力则呈现空间回流效应;(3)提升土地出让对长江中游城市群经济辐射的促进作用,需要更加注重城市间合作和配套的产业链引资,同时加快农业转移人口市民化,使长江中游城市群土地出让"既能引资,又能留人"。