雅思写作范文参考：城市扩张

　　It has been argued that urban sprawl is the root of many environmental problems. Today, I am offering my viewpoint on this issue and reasons to support my position. What is urban sprawl? Urban sprawl is defined as the increased use of urbanized land by fewer people than in the past . In the past, cities were compact and efficient but recently the density of land utilized per person has seen a major decline in the United States. From 1982-1997, the United States population had grown by about 17 percent, while the urbanized land had increased by about 47 percent during the same period in time . Developed land per person has just about doubled in the last two decades and the sizes of housing lots larger than ten acres can account for over half of the land that was developed since 1994 . This drastic change in urbanized areas has been met by both environmental impacts, as well as financial and time burdens on the people.

　　Along with the loss of farmland, there is a loss of wildlife habitats that are disappearing due to urban sprawl. These forests, meadows, and wetlands are disappearing and being substituted with pavement, buildings, and sterile urban landscaping. This loss of wildlife habitats make it hard for species to survive and makes it difficult for them to find suitable breeding ponds, hibernation sites, feeding locations, and to create practical nesting areas . The urban sprawl has been so bad in some places that species of plants are becoming nearly extinct. For example, the Oak Savannas and the Oak and Pine Barrens both have been degraded to the point that there is less than 1 percent of the original species still around .Urban sprawl has contributed greatly to air and water pollution as well as increased water and energy consumption. Since urban sprawl places people outside of walking distance to shopping areas and work areas, they are forced to rely heavily on cars to get from point A to point B. This over reliance on vehicles has contributed significantly to air pollution and greenhouse gases . Pollution from vehicles is usually the number one cause of pollution in many urbanized cities, such as Los Angeles. Another thing to think about would be the recent heat waves that have been experienced in the past month across the nation. People fail to realize that urban sprawl and pollution, which is a by-product of urban sprawl, have contributed significantly to the high temperatures this summer . Urban sprawl increases the amount of concrete and asphalt, thus holding in the heat and making it even warmer than it would have been had sprawl not occurred. Another part of this would be that the pollution leads to higher levels of humidity in the air and in turn exaggerates the effects of greenhouse gases .

　　The effect that urban sprawl has had on people in general would be the fact that taxes are increasingly higher. Urban sprawl can cause increased traffic making work commutes longer and using more gas and creating more pollution . There are higher costs for services such as refuse pickup and water supplies. The air quality can diminish and become toxic to people. For example, in my state of Washington, we periodically experience times where the air quality is poor and people who are on oxygen or have other health related problems are advised to not be outside. This is a problem caused by urban sprawl.

　　I believe urban sprawl has caused multitudes of environmental problems. Since people are using more resources than they need, they are undermining the efforts to create sustainability. Further, the pollution that comes with urban sprawl is having effects which support the issue of global warming. I believe something needs to be done to promote smart growth and sustainability. For instance, using subways and buses or living close enough to work to walk will help dramatically. If we take a proactive approach to this problem, over time we may be able to live in an environmentally stable world.