Environmental Problems, Their Causes, and Sustainability 1

NewarkAllentownHarrisburgBaltimoreWashingtonBowash (Boston toWashington)PhiladelphiaSpringfieldHartfordNew YorkDetroitChicagoToledo AkronChipitts (Chicago to Pittsburgh)BostonProvidenceClevelandPittsburghFigure 25-7 Two megalopolises: Bowash, consisting of urbansprawl and coalescence between Boston and Washington,D.C., and Chipitts, extending from Chicago to Pittsburgh.For more than 6,000 years, cities have been centersof economic development, education, jobs, technologicaldevelopments, culture, social change, andpolitical power. The high density of urban populationsprovides governments and businesses with significantcost advantages in delivering goods and services.Urban residents in many parts of the world livelonger than rural residents, and urban populationstend to have lower infant mortality and fertility rates.In addition, urban dwellers generally have better accessto medical care, family planning, education, andsocial services than people in rural areas.Urban areas also have some environmental advantages.For example, recycling is more economicallyfeasible because of the large concentrations of recyclablematerials, and per capita expenditures onenvironmental protection are higher in urban areas.Also, concentrating people in urban areas helps preservebiodiversity by reducing the stress on wildlifehabitats.many of their non-working hours driving to and fromwork, or running errands over a vast suburban landscape.This leaves many of them with little energy andtime for their children and themselves, or getting toknow their neighbors.In 2003, Reid Ewing and other researchers discovereda connection between sprawling suburbs andspreading waistlines. They found that people living insuburbs, where it is hard to get anywhere on foot or bybicycle, are heavier than those in central cities and inpedestrian-friendly towns.As they grow and sprawl outward, separate urbanareas may merge to form a megalopolis. For example,the remaining open space between Boston, Massachusetts,and Washington, D.C., is rapidly urbanizing andcoalescing. The result is an almost continuous 800-kilometer-long (500-mile-long) urban area that issometimes called Bowash (Figure 25-7 and Figure 25-4,bottom).Megalopolises developing all over the world includethe area between Amsterdam and Paris inEurope, Japan’s Tokyo–Yokohama–Osaka–Kobe corridorknown as Tokohama, and the Brazilian industrialtriangle made up of São Paulo, Rio de Janeiro, andBelo Horizonte.25-2 URBAN RESOURCE ANDENVIRONMENTAL PROBLEMSCase Study: What Are the Advantages ofUrbanization? Concentrating People HelpsUrban areas can offer more job opportunities andbetter education and health, and can help protectbiodiversity by concentrating people.Case Study: What Are the Disadvantagesof Urbanization? Concentrating PeopleHas Some Harmful EffectsCities are rarely self-sustaining, and theythreaten biodiversity, lack trees, grow littleof their food, concentrate pollutants and noise,spread infectious diseases, and are centersof poverty, crime, and terrorism.Although urban dwellers occupy only about 2% of theearth’s land area, they consume about three-fourths ofall resources. Because of this and their high waste output(Figure 25-8), most of the world’s cities are notself-sustaining systems.Large areas of land must be disturbed and degradedto provide urban dwellers with food, water,energy, minerals, and other resources. This decreasesthe earth’s biodiversity. Also, as cities expand they destroyrural cropland, fertile soil, forests, wetlands, andwildlife habitats. At the same time, they provide littleof the food they use. From an environmental standpoint,urban areas are somewhat like gigantic vacuumcleaners, sucking up much of the world’s matter, energy,and living resources and spewing out pollution,wastes, and heat. Thus, urban areas have large ecologicalfootprints (Figure 1-7, p. 10) that extend far beyondtheir boundaries. If you live in a city, calculate its ecologicalfootprint by going to the website www.redefiningprogress.org/.Also see the Guest Essay on thistopic by Michael Cain on this chapter’s website.In urban areas most trees, shrubs, and other plantsare destroyed to make way for buildings, roads, andparking lots. Most cities thus largely lose the benefitsprovided by vegetation that would help absorb airpollutants, give off oxygen, help cool the air throughtranspiration, provide shade, reduce soil erosion, muf-568 CHAPTER 25 Sustainable Cities