Some findings have revealed that cities around the world are growing large. Could you outline the possible causes and predict consequences?
概述：城市化是一个越来越受关注的社会问题。城市化(urbanization or urban sprawl)是指农村地区建立城镇，或者是城市不断地向农村扩展(expansive growth of a metropolitan area)。
•人口增加和移民(an unprecedented population growth and migration)造成基础设备不足(devoid of basic amenities),导致原有的基础经费不足，城市条件恶化(urban decay),于是城市居民开 始迁居城外，导致城市的扩展;
•随着经济的发展和家庭收人的提高(strong economy and increasing household incomes),人们 开始喜欢低密度的住宅区(strong preference for lower-density housing);同时，由于人们可以 支付得起汽车等交通的费用(able to afford the automobile),这也使得人们更易迁居城外;
•城市规划不当(bad city planning)导致道路的建设和基础设施的扩建(construction of roads and the provision of infrastructure)与地区统筹发展不协调(unplanned development),最终使得城市 居民迁居城外。
•环境影响(environmental impact)：郊区的景观千篇一律(monotonous suburban landscapes);空 气污染,有害健康(ill-health due to air pollution generated by traffic);
•社会影响(social impact):城市人口流动增大(high mobility)会导致犯罪率的上升(a surge in the crime rate),人们不会有社区的感觉(sense of community),人与人之间的关系比较短暂 (abbreviated),社区的团结和价值不复存在(loss of community spirit and values);
•经济影响(economic impact):在郊区建设基础设施导致政府财政压力(adverse fiscal impacts),对基础设施的要求不能够被满足(unmet demand on infrastructure);交通堵塞(traffic congestion )影响工作效率，延误商品和服务的输送(delay the delivery of goods and services)。
Of those issues that have concerned the government, academics and the public throughout the world, urban sprawl is one of the most prominent. There are conflicting views toward this growing trend. While it has been taken as a positive development in many newly emerging cities, it is increasingly perceived as a threat to rural environment and considered as a trigger for numerous urban problems. The objective of this essay is to evaluate the forces behind this trend and its consequences.
Population growth is widely recognized as the primary reason. The room in the city centre is so limited that it fails to provide enough housing to accommodate an ever-growing population. Another problem that has intensified in the inner city is infrastructure shortage and poor conditions of buildings. Lack amenities, such as water and electricity supply, waste disposal, swage treatment, to name but a few, has left no choice to urban dwellers but to resettle in the suburbs, where they have easier access to new facilities.
City dwellers are not always moving outward unwillingly. The continued increase in household incomes gives renewed impetus to urban development. People nowadays have higher expectations for quality of life and a growing appetite for lower-density housing with a larger open space. It is possibly the main reason why the real estate market has its focus now on the outskirts of the city, but not on the centre. In the meantime, the affordability and ubiquity of car ownership has made transport a less serious concern for those living in suburbs. They can commute daily between the place of work and the place of residence with ease.
The sustained expansion of cities will make a marked impact on the society in several dimensions. The high traffic volume between suburbs and urban areas would cause severe air pollution and reduce the lands suitable for farming. Urban sprawl requires large developments, causing areas to lose some of their unique qualities and characteristics. From the economic perspective, the relocation of a high population in suburbs will pose adverse fiscal impacts on the local government in infrastructure construction. To those who used to live in suburbs, the inflow of new inhabitants would damage the community spirit and make relations between neighbours fragile.
Urban sprawl is, therefore, a trend which has a strong effect on the environment, communities and government budgeting. When urban decay and citizens' desire for higher standard of living make this trend irreversible, the emphasis should be placed on planned and sustainable development.