Environmental Engineering Reference
In-Depth Information
Natural Capital Degradation
Urban Sprawl
Land and
Biodiversity
Human Health
and Aesthetics
Water
Energy, Air,
and Climate
Economic Effects
Loss of cropland
Contaminated
drinking water
and air
Increased runoff
Increased energy use
and waste
Higher taxes
Loss of forests and
grasslands
Increased surface
water and groundwater
pollution
Decline of
downtown
business districts
Increased air pollution
Weight gain
Loss of wetlands
Increased greenhouse
gas emissions
Noise pollution
Increased use of
surface water and
groundwater
Increased
unemployment in
central city
Loss and
fragmentation of
wildlife habitats
Sky illumination
at night
Enhanced global
warming
Decreased storage of
surface water and
groundwater
Loss of tax base in
central city
Increased wildlife
roadkill
Traffic congestion
Warmer microclimate
(urban heat island
effect)
Increased soil erosion
Increased flooding
Decreased natural
sewage treatment
Figure 7-17
Natural capital degradation:
some undesirable impacts of urban sprawl or car-dependent
development. Do you live in an area suffering from urban sprawl?
and per capita expenditures on environmental protec-
tion are higher in urban areas. Also, concentrating
people in urban areas helps preserve biodiversity by
reducing the stress on wildlife habitats.
7-6 URBAN RESOURCE AND
ENVIRONMENTAL PROBLEMS
Advantages of Urbanization
Urban areas can offer more job opportunities and
better education and health, and can help protect
biodiversity by concentrating people.
Urbanization has many benefits. From an
economic
standpoint,
cities are centers of economic development,
education, technological developments, and jobs. They
serve as centers of industry, commerce, and trans-
portation. However, this is changing as suburban and
exurban areas not dependent on central cities grow.
In terms of
health,
urban residents in many parts of
the world live longer and have lower infant mortality
rates and fertility rates than do rural populations. In
addition, urban dwellers generally have better access
to medical care, family planning, education, and social
services than do their rural counterparts.
Urban areas also enjoy some environmental ad-
vantages. For example, recycling is more economically
feasible because concentrations of recyclable materials
Disadvantages of Urbanization
Cities are rarely self-sustaining. They threaten
biodiversity, lack trees, grow little of their food,
concentrate pollutants and noise, spread infectious
diseases, and are centers of poverty, crime, and
terrorism.
Although urban populations occupy only about 2% of
the earth's land area, they consume three-fourths of its
resources. Because of this high rate of consumption
and their high waste output (Figure 7-18), most of the
world's cities are not self-sustaining systems.
Urbanization can help preserve biodiversity in
some areas. On the other hand, large areas of land
must be disturbed and degraded to provide urban
dwellers with food, water, energy, minerals, and other
resources. This activity decreases and degrades the
earth's biodiversity. As cities expand and sprawl out-
