城市的可持续发展：对于城市化国家的战略思考（中译英）

城市的可持续发展：对于城市化国家的战略思考

一、可持续发展

所有社会都表现为四中要素：自然、人力、资本和信息资源，这四种要素都是社会发展所必需的：

（一） 人们可以从它们之中提取或以其他方式获得它们 （二） 它们能处理或变换资源

（三） 它们分配并调拨那些被处理的资源

（四） 它们作为个人、家庭、社区和国家消费和利用资源

如果在环境补充资源之前将它们耗尽，那么开采的资源就超过了环境的容量，就会造成破坏。当传统方法在提取、处理、分配和消耗资源时将制造出的废料排入空气、土地和水，环境污染也同时发生了。但发展本身，无论是经济的、技术的、社会的还是文化的都不是资源耗尽和环境污染的原因。真正的起因是发展中的处理不当： 社会选择引领其发展的方针是经济、财政、社会和文化制度机制政策，环境和城市地区的发展政策、组织结构、管理系统和法律章程。这些社会制度机制都是由一个可以判断社会道德规范的社会价值体系产生的。不可持续的发展是一种不平衡的发展，其耗尽了不可再生的资源，而在可再生资源上消耗大于恢复，产生的环境污染破坏了环境的生产和繁殖能力。而可持续发展则是一种平衡的经济、社会、文化和技术改善过程，从某种程度上看其发展过程中并不破坏生态系统和耗尽自然资源。这种发展意味这人力资源的比重加大，社会公众的能力对经济、社

上海大学毕业设计(论文)

会、技术和文化起到增进作用。 而这十分需要依靠的足够的资本和信息资源来达到，仅仅注意适当的处理自然资源而不注意对人、资本和信息资源的加强，最后不能称其为可持续发展。一个国家如果没有重视人民居住问题，那么可持续发展就不会发生。在没有解决人民居住之间的联系系统前，国家的农业、林业、渔业和工业就不能持续发展，而可持续发展的提议也就不能实施。人的居住地不单是城市：随着本世纪后期人口的增加，人类居住地间人口流动的频繁，城乡社会之间的差别正在迅速缩小：在可持续发展的规划中，村落，村镇，城镇和城市在城市化的国家构成了错综复杂、密不可分的经济、社会和监管制度。当第三世界国家和发展援助组织的决策者开始埋头苦干可持续发展是，他们必须仔细地考虑到人的居住地在自然资源的获取，消耗、处理和分配过程中的角色。他们必须发展战略，确保持续的城市发展。 二、国家城市类型学

传统观点认为世界是由发达国家和发展中国家组成的。而一种更加精确的都市类型学，提供了更好的关于城市发展的讨论和判别，他们根据城市的增长发展将传统意义上的国家分为以下四类：

（一）城市化的国家，例如加拿大、美国、欧洲国家，东亚少数国家和南美洲大多数国家，这些国家不再需要应对巨型的人口涌入城市地区。相反他们需要考虑的问题与城市服务、基础设施的运转、维护和修复有关。这些国家如何做会对资源消耗、环境污染和人类健康方面产生重大影响。作为一个巨大的棘手问题的征兆，人们也许会注意到：加拿大是世界上人均能源消耗最高的国

1

上海大学毕业设计(论文)

家，其人均比日本人多消耗三倍能量，更比中国人多消耗二十倍。作为一个高度城市化的社会，这种能源消耗大多数明显发生在城镇及其周边地区。加拿大每年产生的危害工业废料中，80%未被处理就被倒入水和空气中，墨西哥城中每一百个新生智障婴儿中就有一个会想到是由大气污染造成的。

（二）几乎城市化的国家，主要是北非、中美洲、和中东的部分国家。这些国家需要应对的是发展的挑战，在极短的时期内，巨型的资本和制度的确定给它们带来良好的工业和城市基础设施，而这些能让它们制定一个在经济、技术、社会和文化方面可持续的增长计划来进入下个世纪。 它们也将制定一个关于资源消耗和污染的框架，而这将对其环境卫生产生影响。这里有一个关于该种类型和程度的典型例子：大城市亚历山大的婴儿死亡率超出埃及整体水平，这是由该地区的水源遭受污染带来的寒热症，肝炎和痢疾造成。

（三）快速城市化的国家，大部分在亚洲和非洲。这些国家面对一项艰巨任务，就是要在接下来的一个世纪利用两到三代人快速发展。它们目前是世界上的最穷的国家之一，而且面临着大量的人口汇集到城市之中。这些国家普遍存在的问题是现有的城市基础设施在数量和质量上都不完备，并且城市和环境管理效率底下。这些问题导致土地的严重耗尽、水和木材资源紧张，水和空气严重污染。这类型国家问题的案例是：在快速城市化国家城市的市区面积预计在1980年到2000年间翻了一倍，8百万公顷增长到超过17百万公顷。这其中大部分城市扩张所使用的土地是当时的农林用地。在曼谷，一个快速城市化的大都会，过度的消耗新鲜

2

上海大学毕业设计(论文)

地下水导致其南部和东部下沉5到10cm(比在威尼斯在它下沉最快的时期还快)，还伴随着对建筑物、地表和地下基础设施的冲击。在1980到1985年间，孟加拉国、缅甸、印度、尼泊尔和泰国都市居民占有的饮用水数量下降了，而于此同时它们的农村居民的饮用水数量却上升了。国内的工业污染将处于河流下游的雅加达、汉城和马尼拉的渔场全部消除。马尼拉已知道肺癌和其他呼吸道疾病有48%的起因是空气污染，而在加尔各答60%的呼吸道疾病是空气污染造成的。

（四）适度城市化国家，像是缅甸、柬埔寨和斯里南卡，这些国家的城市化进度通常较低。

而中国，尽管它的都市生长率不象那些快速城市化国家那样高，但它有2亿的城市人口严重的环境问题在许多中国城市仍然存在。在上海，被污染的黄浦江和苏州河被认为是这个城市80%癌症的起因。1988年，肝炎在上海传播，肝炎感染了120万居民并且夺去了数以万计生命，这一事件的起因是居民食用了沾染长江污水的蛤蜊。在中国，低质煤炭是国家的主要使用能源，这使得肺癌患病率都市是全国平均水平的四到七倍。

这四种国家所面对共同性问题就是自然环境，虽然优先处理的问题随它们自身变化而变化。 但是其中每一个国家也会面对独特的问题和机遇。因此，领导人，特别是那些发展中国家援助机构中的，在选择可持续发展战略时必须清楚的认识到这种共性和特性。

三、城市系统类型

国家城市化水平正如上文所述，而城市的可持续发展战略规

3

上海大学毕业设计(论文)

划还被关于城市系统的计划深深影响。战略上的思考、目标、政策以及制度机制，需要反应对城市化水平的应对，因此城市被分为以下类型：

（一）中间和次级城市：在中型和次级城市的规模上公众并没有一个同一的意见，墨西哥的中间城市就明显和卢旺达的大都会差不多。然而在1980年第三世界有超过80%的城市人口居住在少于10万个居民的城镇中。中间和次级城市的重要性主要在于把农业生产商连接到全国和国际市场。由于其小型化和关联性，这些城市在国家关于农业生产、制造和进口替代的许多政策上扮演着愈加重要的角色。

（二）大城市地区：这些居住地大小不等从100万至2000万人。它们的特点是规模大，形式单一，在其界内有高度集中的正规和非正规的经济活动，而且普遍比较贫困。在这个十年的后期，将会有83个大城市地区诞生在几乎城市化，快速城市化或适度地城市化的国家，多数在亚洲。

（三）特大的城市：一种新出现的解决可持续发展挑战的形式，过去还不能被很好了解。这种形式最近开始在已经城市化和正在城市化的国家涌现，就是是“特大的城市”。不同于“巨大，单一城区的大城市”，特大的城市被描绘成是人口从2000万到1亿，包括至少两个大城市极的地区。城市被农田，森林和小城市围绕，而且有一个连接乡村和小城市的系统，连接两极主要交通轴线十分强大，分配和服务于频繁的“交易”经济活动，并有明显的倾向，作为经济，社会和技术的“网关”，对外连接世界。

在明确的可持续城市发展战略中必须考虑到那种高度综合和

4

上海大学毕业设计(论文)

处于动态中的的结合城区，如大城市地区和中间城市带来的影响，而这些城市分布在那些对地球环境影响日益增加的增加的国家，例如中国、印度尼西亚、孟加拉国、菲律宾、巴基斯坦、印度和南美洲的部分国家。

四、可持续城市发展战略的原理

每个城市、大城市、特大的城市和国家都需要开发它自己，局部的可持续发展战略会对现有的环境状况、社会经济的系统和社会统治结构产生影响。然而，有些关键的原理看起来很普通。国家需要重视这些原理，根据城市化的形式和水平变化计划。 （一）不可更新的资源的保护：在全球有很多的行动被承诺用来保护不可更新的资源保护，这些行动包括：采取增加现有土地使用率用来保护土地的政策；在几乎城市化和快速城市化的国家实施建立全面公共交通工具用以减少私家车使用的政策；调控交通运输工具的数量将可燃性矿物资源的消耗量减到最小；保护的沼泽地和沿海水域；建立野生生物保护区域。

（二）寻找替代能源：不可更新的资源和某些人造能源需要寻找可更新的资源来替代。最明显是石化燃料可替换为其他一些创造的能源，除太阳能和风能之外，沼气能量已经很早就在印度被使用。其他的包括建筑产品的替换，从不可更新的资源被人造的零出料材料所替代，或通过其他自然资源所替代。例如传统的多孔黏土技术在秘鲁开始慢慢地替换粘结剂技术，石工建筑被利用和氟氯烃化合物被替换。现在一套全面的关于可利用的替换资源目录需要被制定，用来规范在各种城市环境的使用标度，范围从特大的城市到工作场所和家。

5

上海大学毕业设计(论文)

（三）资源修复：修复沿海地区、湿地、蓄水层、森林和野生动物栖息地，这些行为可能发生在城市地区并且对城市本身有益，甚至建立城市公园也扮演主要角色：十棵落叶树木每年可吸收约4吨碳，和加拿大人均产生数量差不多。第三世界国家可以在市区边缘造林，以适当的做法，确保可持续产量，这可以提供急需的燃料。同时它也可以大幅度减少水土流失以及解决随后城市基础设施的淤塞问题。其提供的鱼类和野生动物提供了一个重要的食物来源，可以使地方的生态系统和经济水平双双收益，在第三世界国家，这还有助于增进出口收入，例如，虾养殖业。 （四）循环利用：如果是比较谁对持续都市发展更有用，那废物循环利用一定是远在垃圾清理之上。曾经无用的废物现在被认为可以变成各种各样可能应用的原料。例如在牙买加从铝土矿的废物提炼产品被用在砖制造业中；用米果壳和鼓风炉炉渣燃烧产生的灰来替代能源消耗巨大的水泥，如今在巴西被应用；在阿根廷，人们用热电厂煤粉燃烧的副产物代替水泥灌入混凝土中，并且可以用天然火山灰代替水泥。在循环使用展现效率和创新的同时，必须是以持续都市发展为前提。

（五）控制废物的排放：过去的几年，技术上的飞跃为控制和处理污染环境的各式废气和废水提供了有效的方式。至少在许多已经城市化的国家，除了控制汽车排放和烟窗改造技术之外，废气和工业污水处理系统也都迅速成为城市基础设施的要素。然而，许多正在城市化的国家的城市在控制和处理废物上的城市系统和技术严重落后。例如，上海的黄浦江因为污染在一段时期内每年有150天，河水含氧量极低；而这之中80%污水是工业污水包括

6

上海大学毕业设计(论文)

含有高浓度砷、水银、酚、铬、铅和锌的废水。上海的环境保护局试图控制这些工业废料的排放，并在许多工厂安装了污染处理的系统，但许多工厂为了介绍能源使用费用在环保局检查之后就将这些系统关闭。与污染控制相比，污染处理使一项需要更多技术的任务，它需要经济、政治、制度各个社会要素的积极配合。 （六）非可再循环废物的管理：有一些废物明显是不可再循环的，这就需要管理阶层对许多含毒物和放射性材料存放进行管理。这类废料大多数都在城市产生，现在技术可以使安置和利用这类变得更加安全，但问题的关键使城市的支付能力。而这类废料的转储站点依旧在城市地区和它们所管辖的地区，即使外界环境或经济政权减少这类非可循环废物的产生，但仍要继续执行遏制含毒物和放射性材料的使用的政策。

（七）资源分配：可持续城市发展战略中，关于资源分配问题需要在两个方面加以注意。第一个方面涉是在第三世界国家的许多农村地区，人们认为资源应该集中分配到农村。这种观点是基于“城市是差的”以及“城市耗尽农村”的认知。这样，如果更多的关注被放在应对乡村地区的资源分配需要，城市的增长就不会发生。然而，人们搬到城市去不仅仅是为了在经济上的获得，还有其他社会、文化和政治的原因。在第三世界国家的城市中，城市人口成长60%是内部原因引起的。应此这场关于农村或城市资源分配的辩论将很快变得多余了。

第二个需要关注的重要方面是在所有的第三世界国家贫富之间的差距。改善穷人使用社会资源的权利，是每个社会经济政权进行可持续城市发展的基础。很明显的，资源的公平分配是全球

7

上海大学毕业设计(论文)

性可持续发展原理中的基本要素，无论它们是已经城市化的国家还是正在进行城市化的国家。

（八）体制上的变动：无论政权如何承诺支持可持续的城市发展，或者什么潜在技术可能有效地处理污染，不在城市和自然环境的发展和管理的体制上学会变化，可持续的城市发展就不会发生。这里有各式各样的可有运行的机制，包括很多政策和具体处理事情的办法。 五、政策和措施

对日用品和便宜的工业品的反复消耗日益增加，已经城市化的发达国家通过不对等的贸易政策和措施，将资源消耗和环境污染带给了第三世界国家。

财政和金钱措施，例如税收政策，提供经济刺激，使得人们耗尽不可更新的资源并增加了环境污染；阻止资源公平分配社会经济的政策，特别用在在对城市贫穷人口上。第三世界的许多国家20世纪50年代公布的城市发展政策都是根据最大限度的使用近似无限的资源如土地、水和化石燃料的原则。而在投资策略上要创办资本和所花费用减到最小，而不是选择长期的优质产业。这些政策都阻止城市政府获取足够的收入，而这些收入会被用来恢复环境，提供城市服务供应和进行市政基础设施建设和管理控制措施，在绝大多数范围内不容易地执行，并且不让公众能够充分调查。在政府和产业计划组织机构时并没有采用垂直和横向一体化形式，且排除了公众的监督。这需要我们进行管理结构的改革，使其它正式地存在，远离地政府的政策制定，并且认识到不足并进行技术上的训练，使专业和管理人员能提供一个可持续的

8

上海大学毕业设计(论文)

城市发展战略，并实施它，这样国家就能向城市化方向上更进一步。有效的体制变动能使国家城市化，并且达到城市化，这将是可持续城市发展的基础。没有它们，任何可持续发展的愿景都将是空的。

9

上海大学毕业设计(论文)

附录2，英译中英文原文 Sustainable urban development: Strategic considerations for urbanizina

nations

Sustainable development

All societies perform four functions with the natural,human, capital and information resources that are required for development: 1．they extract or otherwise obtain them; 2．they process or otherwise transform them;

3．they distribute and allocate the processed resources

4．they consume or utilize resources as individuals, families, communities and nations.

Extraction of resources beyond the capacity if the environment to replace them in resource depletion. Pollution of the environment occurs when methods used in extracting,processing,distributing and consuming resources creates wastes that arr discharged into air,land and water Development itself - be it economic, technological, social or cultural - is not the cause of resource depletion and environmental pollution. The cause is poorly managed development: the methods that society chooses to guide its development are the institutional mechanisms of economic, financial, social and cultural policies, environmental and urban/regional development policies, organizational structures, management systems, and laws and regulations. These institu-tional mechanisms result from a society’s system of values that determine its ethics.Unsustainable development is inequitable development that depletes non-renewable resources, consumes renewable resources at a rate faster than the ecosystem can regenerate them, and undermines the productive and reproductive capacities of the natural environment through pollution. Sustainable

10

上海大学毕业设计(论文)

development is the process of equitable economic, social, cultural and technological betterment in a way that does not pollute ecosystems and deplete natural resources. Sustainable development implies the enhancement of human resources, the capabilities of communities to work towards economic, social, technological and cultural enhancement. It is heavily dependent on the attainment of sufficient capital and information resources. Simply addressing the proper management of natural resources without paying equal attention to the strengthening of human, capital and information resources will not, in the end, lead to sustainable development.Sustainable development cannot occur in any country without carefully taking into account its human settlements.Initiatives cannot be successfully undertaken in ensuring the sustainability of a country’s agriculture,forestry, fisheries and industries without addressing the context of the system of human settlements in which they occur. Human settlements are not only cities: with the increase in transactional flows that are occurring between human settlements in the latter part of this century, the historical distinction between urban and rural societies is quickly diminishing: hamlets, villages, towns and cities in urbanizing nations constitute intricate economic, social and regulatory systems that cannot be disaggregated in planning for truly sustainable development.As policy makers in Third World countries and development assistance agencies begin to grapple with sustainable development, they must carefully take into consideration the roles of human settlements in the extraction,consumption, processing and distribution of natural resources. They must develop strategies for ensuring sustainable urban development.

An urban typology of nations

There is a tradition of viewing the world as a construct of “developed” and “developing” nations. A more precise,urban typology, however, will better inform discussion and action on sustainable urban development. Countries can be classified by the kinds of urban growth they are currently experiencing (fig. 5) in the following four categories:

1.Urbanized countries such as Canada, the US, nations of Europe, the East Bloc, and most of South America;these countries no longer need to deal with massive population influxes into urban areas. Rather they are facing issues related to the operation, maintenance and rehabilitation of urban services and infrastructures. How they go about doing this will have significant impacts

on resource depletion, environmental pollution and health. As an indication of the magnitude of the issues involved,one may note that:

11

上海大学毕业设计(论文)

anadians are the highest per capita consumers of energy in the world; on a C

per capita basis, they consume three times more energy than the Japanese and twenty tlmes more than the Chinese; being a highly urbanized society, most of this energy consumption clearly occurs in towns, cities and metropolitan regions2;

Of Canada’s hazardous industrial waste, 80 percent is dumped untreated into the aqueous and gaseous environment each year; One of every one hundred new-born children in Mexico City suffers from mental deficiencies thought to becaused by air pollution.

Nearly urbanized countries are principally countries in North Africa, the Middle East and parts of Central America; these countries are responding to the challenge of making, over a very short period of time, massive capital and institutional commitments to industrial and urban infrastructures that will set the course for their continued economic, technological, social and cultural development well into the next century. They will also provide the framework through which resource depletion, pollution and their effects on environmental health will occur. A typical example of the type and scale of problems may be given:

The infant mortality rate in metropolitan Alexandria exceeds that of Egypt as a whole: typhoid, hepatitis and dysentery transmitted through polluted water bodies are endemic.3

? Rapidly urbanizing countries are most of the countries of Asia and Africa.

These nations face a daunting task of compressing centuries of development into a period of two or three generations. They are among the poorest countries in the world yet are facing massive population influxes to cities. The quantitative and qualitative inadequacies of existing urban infrastructures, and the inefficient urban and environmental management systems that generally exist in these countries, are causing severe depletion of land, water and fuelwood resources and serious pollution of water and air. Examples of characteristio problems are:

The physical size of urban areas in rapidly urbanizing nations is expected to double from 8 million hectares to more than 17 million hectares between 1980 and the year 2000; much of this expansion will be on land currently used for agricultural and forestry purposes[4];

Over-consumption of fresh groundwater in the southern and eastern parts of Bangkok, a rapidly urbanizing metropolis, has led to their sinking by 5 to 10 cm a year (a rate faster than in Venice during its worse period of subsidence) with

12

上海大学毕业设计(论文)

concomitant impacts on buildings and surface and below-grade infrastructure[5];

The percentage of urban dwellers with access to potable water in Bangladesh, Burma, India, Nepal and Thailand declined between 1980 and 1985 yet rose for their rural populationss.

Domestic and industrial pollution is wiping out fisheries in areas downstream from Jakarta, Seoul and Manila;

Air pollution is known to be the cause of 48 percent of all lung cancer and other respiratory diseases in Manila7;

In Calcutta 60 percent of the population suffers from respiratory diseases caused by air pollutlon Moderately urbanizing countries are the countries of Burma, Kampuchea and Sri Lanka in which urban growth rates are generally quite low. However, China, even though its urban growth rates are not as high as in rapidly urbanizing countries, has an urban population of over 200 million people. Serious environmental problems exist in many Chinese cities:

Shanghai’s Huangpu River and Suzhou Creek are so polluted that they are believed to be the cause of 80 percent of that city’s cancer fatalities*;

The hepatitis epidemic in Shanghai in 1988, that struck 1.2 million residents and claimed the lives of thousands,was caused by untreated sewage contaminating clam beds near the Yangtse River[10];

Lung cancer in urban China is four to seven times the national average - low-grade coal is the major energy source in China.The regional distribution of these four types of countries is shown in figure 6. Each of these fourtypes of nations faces common issues vis-à-vis the natural environment,although priorities for dealing with them vary. But each also faces unique problems and opportunities. Policy makers, therefore, particularly in development assistance agencies, must clearly recognize both the commonalities and the differences in addressing strategies for sustainable urban development. Types of urban systems

the levels of urbanization described above but also to Strategic planning for sustainable urban development will be heavily influenced by the type of urban system being planned for. Strategic considerations - objectives,policies and institutional mechanisms - will therefore need to respond not only to the exigencies posed by the levels of urbanization described above but also to the following forms of human settlement:

intermediate and secondary cities: There is no universal consensus on the size of intermediate and secondary cities. A secondary city in Mexico

13

上海大学毕业设计(论文)

would clearly correspond to a huge metropolis in Rwanda. However, in 1980 over 80 percent of the urban population in the Third World lived in cities and towns with less than 100,000 inhabitants.12 The importance of intermediate and secondary cities is largely in their linkage of rural agricultural producers to national and international markets. Characterized by their small size and interconnectedness, these cities are playing increasingly important roles in the implementation of many national policies on agricultural production, productivity and import substitution.

Metropolitan regions: These settlements vary in size from 1 million to

20 million people. They are characterized by their large size, a mononuclear form,high concentrations of formal and informal economic activity within their boundaries, and widespread poverty.By the end of this decade, there will be 83 metropolitan regions in nearly urbanized, rapidly urbanizing and moderately urbanizing countries. Most will be in Asia

Megalopolis: The emergence of a new, higher-order form of settlement poses challenges to sustainable development that are not nearly well enough understood.A form of settlement that has recently begun to emerge, both in urbanized and urbanizing nations, is \Unlike “mega-cities” which are huge,mononuclear metropolitan regions, a megalopolis is characterized by comparatively large populatfons ranging from 20 million to 100 million, a band-like urban struc ture consisting of at least two metropolitan poles surrounded by agricultural land, forests and a closely-linked system of smaller cities and towns, strong connectivity between the poles along a major transportation axis,strong “transactional” economic activity in distribution and services, and a marked tendency to act as an economic, social and technological “gateway” to the outside world.

The impact of this highly complex and dynamic form of human settlement - combining both metropolitan regions and intermediate and secondary cities – on regional and global environments must be taken into account in the formulation of strategies for sustainable urban development in an increasing number of countries,such as China, Indonesia, Bangladesh, Philippines,Pakistan, India and in parts of South America.

Elements of a strategy for sustainable urban development

14

上海大学毕业设计(论文)

Each city, metropolis, megalopolis and country will need to develop its own, localized strategy for sustainable urban development that responds to existing environmentalconditions,socio-economic systems, and structures of governance. However, there are some key elements that are likely to be generic. The emphasis that countries need to place on these elements, and the measures adopted for their implementation, will vary according to the level of urbanization and form of settlement being planned for.

Conservation of non-renewable resources: There is a plethora of actions that could be undertaken to conserve non-renewable resources in and around the world’s cities including: setting land use policies that increase densities to conserve land; setting policies and establishing comprehensive mass transit programs to reduce the use of automobiles in nearly urbanized and rapidly urbanizing nations;regulating the volume of automobile traffic to minimize the consumption of fossil fuels;

conserving wetlands and coastal zones;defining or creating wildlife protection areas.

Resource substitution: Non-renewable - and some man-made - resources need to be replaced with those that are renewable (fig.12). The most obvious is replacement of fossil-based fuels with other resources in the creation of energy - e.g. aside from solar and windpowered energy, biogas energy as pioneered in India.”Others include replacement of building products created from non-renewable resources by man-made materials manufactured with zero discharge or by other natural resources - such as in Peru where traditional adobe technology is slowly beginning to replace cementintensive,masonry construction15 - and replacing chlorofluorocarbons.Comprehensive directories of locally available, substitutable resources for use at all scales of the urban environment, ranging from the megalopolis to the workplace and the home, need to be formulated.

Resource rehabilitation: The rehabilitation of coastal zones, wetlands, aquifers, forests and wildlife habitats are all actions that can occur in urban areas and benefit them. Even the creation of urban parks can play a major role: ten deciduous trees absorb about four tonnes of carbon a year, as much as is created by the average Canadian. Reforestation of urban peripheries in Third World countries can, under proper practices ensuring sustainable yield, provide badly needed fuel. It can also drastically reduce erosion and subsequent silting of urban infrastructure(fig.13). Restocking of fish and wildlife can benefit local and

15

上海大学毕业设计(论文)

regional ecosystems and economies,provide an important source of food in Third World countries,and contribute to export earnings, for example,shrimp farming.

Recycling: Urban recycling must go far beyond the scavenging of garbage dumps if it is to contribute fully to sustainable urban development. Materials long believed to be useless waste are now being found to have a wide range of possible applications. Examples are: use of waste from bauxite mines in brick manufacturing, as in the case of Jamaical

substituting energy-intensive cement with ash from combustion of rice husks and blast furnace slag, as applied in Brazil[17];replacement of cement in concrete with fly-ash a byproduct of pulverized coal combustion in thermal power plants, as in Argentlna18; and use of natural pozzolans to replace cement, as in Recycling implies efficiency and innovation, prerequisites to sustainable urban development.

Control and treatment of waste emissions: Technological advances over the last few decades have provided many cost-effective ways of controlling and treating a wide range of gaseous and aqueous emissions in the urban environment. Aside from automobile emission controls and smokestack technologies, domestlc and industrial sewage treatment systems are fast becoming essential elements of urban infrastructures, at least in many urbanized countries. However, most cities in urbanizing countries lag seriously behind in the introduction of systems and technologies to control and treat waste.For example, Shanghai’s Huangpu River is so polluted that, in some stretches, it is anaerobic for 150 days of the year; 80 percent wastewater pollution is of industrial origin and consists of high concentrations of arsenic,mercury, phenol, chromium, lead and zinc.2° Even though Shanghai’s Environmental Protection Bureau attempts to regulate industrial waste emissions and many factories have installed source treatment technologies, these systems are routinely turned off after EPB inspections in order to reduce energy costs.21 Waste control and treatment is more than simply a technological task. It is a function of economic, political and institutional factors as well.

Management of non-recyclable waste: Some wastes are clearly non-recyclable. Special management regimes are required for many toxics and radioactive materials.

Most of these wastes have urban origins. Technologies are becoming available to safely contain these non-recylable wastes but serious problems remain concerning affordability, the location of dump sites in urban regions and

16

上海大学毕业设计(论文)

in their management. Even if environment/economic regimes are put into place that drastically reduce the creation of non-recyclable wastes,there will always be a continuing need to provide for the containment of some toxic and radioactlve materials.

Resource distrlbution: There are two aspects of resource distribution that require careful attentlon in any strategy for sustainable urban development:

?The first aspect relates to the belief in many quarters that the distribution of resources should be focused on rural areas in the Third World. This contentlon is based on the perception that “cities are bad” and “drain the countryside,” i.e. if more attentlon was paid to distributing needed resources to rural areas, urban growth would not occur. However, people move to cities not only to

seek economic gain but also for social, cultural and political reasons. In many Third World cities up to 60 percent of urban population growth is generated internally.[22 ]The debate over rural/urban resource dlstributlon is quickly becoming superfluous.*The second important aspect that must be addressed is resource distribution within urban areas: the spread between the rich and the poor in all Third World cities.Reforms of socio-economic regimes that constrain the poor from gaining access to resources need to be the cornerstones of a sustainable urban development strategy.

Clearly, equitable distribution of resources is a fundamental element of the sustainable development equation both globally and within cities, be they in urbanized or urbanizing nations.

Institutional change

No matter how strong a commitment to sustainable urban development, or how effectively a technology can potentially deal with pollution, without institutional changes in the development and management of cities and the natural environment, sustainable urban development will not occur. There are a broad range of institutional mechanisms that need to be addressed,including policies and operations. 5..

Policies

Policies and practices in the urbanized North that encourage resource depletion and pollution in Third World countries through unequal trade practices and capricious consumption of commodities and low-cost manufactured goods; ? Fiscal and monetary measures, such as taxation policies,that provide economic incentives to deplete nonrenewable resources and to

17

上海大学毕业设计(论文)

pollute;Socio-economic policies that preclude equitable distribution of resources, particularly to the urban poor;Urban development policies promulgated since the 1950s - and transposed to many Third World countries -that are based on principles of maximum consumption of unlimited resources of land, water and fossil-based fuels;Investment strategies based on minimizing initial capital costs as opposed to optimizing long-term,life-cycle costs; and,Policies that preclude urban governments from generating sufficient revenue, or recovering their costs,in the provision of urban services and ongoing management of municipal infrastructures.

Operations

Regulatory measures, that are insufficient in scope,are not easily enforceable and do not provide forsufficient public scrutiny;

? Organizational mandates and designs in government and industry that preclude consultation, vertical and horizontal integration, and public accountability;

Governing structures that centralize economic and,where it formally exists, environmental decision making away from local communities: and,

? Insufficient and/or inadequately trained technical,professional and managerial personnel to manage urban to be made to provide for the implementation of a sustainable urban development strategy will clearly be infiuenced by the form of settlement and the level of urbanization that a country has reached. Effective institutional changes in ail countries, urbanized and urbanizing alike, will be the cornerstones of sustainable urban development. Without them, prociamations on sustainable development will be empty. rhetoric that do little to improve the quality of life for future, largely urban, generations.

18

本文来源：https://www.bwwdw.com/article/9vig.html