Urban Studies: Urban Sprawl
Urban sprawl has been cited as the main cause of numerous environmental problems. Urban sprawl refers to the continuous growth of cities into the countryside and agricultural lands. It is the dispersion of cities and its environs. Urban sprawl normally involves the infrastructural developments in the rural areas or the undeveloped land at the outskirts of an urban center. When cities expand, the neighboring land and the natural green areas are swallowed up by the built up houses, roads, and other forms of infrastructure to suit the needs and requirements of the residents. Urban sprawl is considered a universal problem, and is an issue to both the developed and the developing countries. In the developing states, the effects of urban sprawl can be life intimidating because of the physical condition and cleanliness issues. The developed countries may not be affected much; however, with the continuous growth of urban land, swallowing up the neighboring land, there is a key threat to the sustainability and quality of life. The long term effects can be overwhelming. Urban sprawl normally begins at an urban, city base and enlarges into the undeveloped land, intimidating animals and plants, polluting the general environment and destroying the agricultural land (Squires, 2002).
The negative environmental consequences of urban sprawl
Many do not realize the less obvious but severe effects that urban sprawl can have on the life of the general population. Some of the negative environmental consequences of urban sprawl include:
- Loss of open space, forest lands, and valuable agricultural lands
The pleasing, beautiful green lands are vanishing and are being replaced by infrastructures such as residential houses, roads, and railway lines. Urban sprawl is consuming most of the open spaces in rapidly growing urban areas so quickly that it could lead to the destruction of about 1,200 species of animals and plants. Sprawl causes danger to these species by wiping out their homes, and their feeding grounds and by blocking their migratory paths. For instance, in the United State, urban sprawl is forecasted to swallow up about seven million acres of agricultural land, seven million acres of the lands that are considered fertile, and about five million acres of another valuable land within the period of 2000-2025 (Squires, 2002).
- Impacts on wildlife and ecosystem
In regions where sprawl is not controlled, the high volumes of the human population in residential and industrial settings may result in the alteration of the pattern and process of the ecosystem. The growth that is associated with sprawl not only leads to a decrease in the total area under forest, farmland, woodland, and the general open space, but also breaks up what is remaining into small portions that lead to the disruption of the ecosystems and fragment habitats. The fragmentation of the huge forested areas into smaller patches disturbs the ecological process and decreases the availability of habitat for a number of species. Some forest fragments become too small to preserve feasible breeding populations of specific wildlife species (Squires, 2002).
- Increase in temperature
The positive association between land surface temperature and the impermeable surface evidently points to the temperature rise in the sprawling regions. During the warm days, the sprawling urban regions can be 6-80 F warmer than the surrounding regions and the effect is referred to as urban heat islands. This heat island effect is as a result of dark surfaces such as roadways and rooftops which absorb a lot of heat and reradiate it in the form of thermal infrared radiations; such surfaces normally reach temperatures of about 70oF which is quite higher than the surrounding temperatures. The other cause of the island effect is that the urban regions are rather devoid of plant life such as trees that could otherwise provide shade and cool air by the process of evapotranspiration. As the urban region sprawls externally, the heat island effect increases both in geographic area coverage and in concentration. This is more obvious, especially if the pattern of development involves widespread tree cutting and numerous road developments (Squires, 2002).
- Poor air quality
Sprawl is considered a factor of air pollution since the car-dependant lifestyle that is imposed by sprawl had resulted in an increase in fossil fuel consumption and emission of greenhouse gases. Urban sprawl greatly contributes to poorer air quality by encouraging the use of automobiles, thus increasing the level of air pollutants like carbon monoxide, carbon dioxide, ozone, and other forms of pollutants in the atmosphere. These pollutants affect the growth of plants, lead to the creation of smog and acid rain, lead to global warming, and also affect human health (Squires, 2002).
- Impacts on water quality and quantity
Sprawl also affects the quality and quantity of water, with the increased infrastructure; rainwater and snowmelt are not capable of soaking into the ground to replenish the groundwater aquifers. Urban sprawl results in an increasing imperviousness, which as a result encourages more total runoff volume. Thus the cities that are located in flood-prone regions are exposed to increased flood hazards such as inundation and erosion (Squires, 2002).
The problem of urban sprawl and examples of sprawl in several cities
As a result of urban sprawl, the land is continually being consumed at a very fast rate as the population shifts from the towns to the suburban fringes (Porter, 2000). For instance, between the years 1950 and 1995, the population of Chicago increased by about 48%, while the land coverage increased by about 165%. Likewise, in the sprawling area of southeast Boston, much more land has been put under development in the last forty years as compared to the preceding three hundred and thirty years. A sprawl that is associated with a rapid increase in population is more apparent in south Florida, where the overall change in the urbanized land is one of the highest in the country (Fulton & Pendall 2001). For instance, it was once reported that out of the thirteen largest United States office markets, south Florida was found to have the lowest percentage of office space in its major city center known as Miami. About 13% only of the South Florida Office space is situated in the Central Business District (CBD).
In the past years, urban regions were compact and efficient, however presently the density of land utilized per individual in the U.S. has greatly declined. Between the year 1982 and 1997, the population in the United States increased by about 17%. During the same time, urbanized land expanded by about 47%. Thus developed land per individual has greatly increased within the last two decades and the sizes of housing lots greater than 10 acres account for over half of the total land that has been developed since 1994. The American farmlands are among the most affected lands. Most of the American farmlands have been lost due to the construction of new roads, edging industrial parks as well as new sprawling residential house development. The loss of these farm lands decreases the ability of food, thread and wood production. In addition, the higher tax rates that is associated with urban sprawl force most farmers in America to close down their businesses and sell their agricultural lands to companies interested in developing new residential houses, as a way of securing their financial security. This problem has mainly affected the state of Wisconsin. In the 1950s, the state of Wisconsin had about 24 million acres of farming land. By 2002, most of the agricultural lands had been lost due to infrastructural development, and only about 16 million acres were left (Fulton & Pendall 2001).
Controlling Urban Sprawl
One way of controlling urban sprawl is by developers setting aside conservation areas within their projects for the purpose of protecting the natural vegetation which in most cases is destroyed by infrastructural development (McKinney 2002). The advantage of this nature of solution is that the conserved biodiversity is also considered apart of the construction. The problem of urban sprawl can also be approached from an economic viewpoint. It has been suggested that the number of endangered species is increasing because of the level of the integrated economy, and thus the casual system of species endangerment has continued to increase. That means that, the economic drivers also contribute to biodiversity loss and therefore must also be considered.
Another way of controlling urban sprawl is through the enforcement of birth control methods. The rood cause of urban sprawl in the United States and any other state is the great increase in population rate. As the population increases and many people move, new developments must always be created to match their needs. It the people purchasing new houses were fewer, there would be no need for developing new houses. The only thing that should be put into consideration when enforcing birth control is ensuring that the population does not get too low, too fast because if it happens that way, it would be difficult to maintain a modern economy with very few people working (Gonzalez, 2009).
Urban sprawl can also be controlled by using new technology to enable people to work from the comfort of their homes. The reason why urban sprawl is occurring is that a big number of people depend on working in a big town and accessing community services that are offered by a big town. There is an incentive to reside near the city because of the perks that are offered by the city. Thus if people were able to access such perks from their homes, it could eliminate the necessity of living near the city. People would therefore have the option of spreading out and living in small neighborhoods and thus urban sprawl would be slowed (Gonzalez, 2009
Fulton, W. B., & Pendall, R. (2001). Who sprawls most?: How growth patterns differ across the US. Washington, DC: Brookings Institution, Center on Urban and Metropolitan Policy.
Gonzalez, G. A. (2009). Urban sprawl, global warming, and the empire of capital. Albany: State University of New York Press.
McKinney, M. L. (2002). Urbanization, biodiversity, and conservation. BioScience, 52(10), 883-884-890. doi:10.1641/0006-3568(2002)052[0883:UBAC]2.0.CO;2
Porter, D. R. (2000) The practice of sustainable development. Washington DC: Urban Land Institute.
Squires, G. D. (2002). Urban sprawl: Causes, consequences, & policy responses. Washington, D.C: Urban Institute Press