Cities are an environmental
abomination. . .
Right?
• “The growth of cities will be the
single largest influence on
development in the 21st century.”
– UN, 1996, State of World Population
Largest urban areas
• 1. Tokyo, Japan - 28,025,000
2. Mexico City, Mexico - 18,131,000
3. Mumbai, India - 18,042,000
4. Sáo Paulo, Brazil - 17, 711,000
5. New York City, USA - 16,626,000
6. Shanghai, China - 14,173,000
7. Lagos, Nigeria - 13,488,000
8. Los Angeles, USA - 13,129,000
9. Calcutta, India - 12,900,000
10. Buenos Aires, Argentina - 12,431,000
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What’s bad about cities?
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Air quality
• Magnitogorosk, RU
• Hyderabad, IND
Air quality
• Primary and secondary air pollution
• Primary: directly emitted
– Particulate matter: pm10 and pm5
– Lead
• Secondary: forms in atmosphere
– Ground level ozone
Impermeable surfaces
Impermeable surfaces
• Don’t allow water to sink into the ground
• Instead, water runs off quickly to storm
drains
– Overwhelms sewage treatment plants, OR
– Goes directly to nearby water bodies
Cities influence climate
• Urban heat island effect
• Roads, buildings, other infrastructure
replace vegetation
• Absorb solar energy during day, radiate heat
at night
– Roofs, roads can be 50-90 deg. F hotter than
air temperature!
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Major Urban Problems in U.S.
• Deteriorating services
• Aging infrastructures
• Budget crunches from lost tax revenues as
businesses and affluent people leave
• Rising poverty with violence, drugs, decay
• Urban sprawl - growth of low-density
development on edges of cities and towns
– 9 consequences of “bad growth”
75% of the US population live
in urban areas occupying 3%
of the country’s land area
Urban Resource and Environmental Problems
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Destruction of plant life - what is $ value?
Cities produce little of own food
Urban heat island effect
Water supply and flooding problems
High pollution exposure
Urban Resource & Environmental Problems
• Excessive noise exposure  health effects
– Hearing loss, hypertension, muscle tension,
migraines, headaches, higher cholesterol levels,
gastric ulcers, irritability, insomnia,
psychological disorders, aggression
Urban Resource & Environmental Problems
• Beneficial effects:
– education
– social services
– medical care
• Harmful effects
– infectious disease spread
• high density population
• inadequate drinking and sewage system
– physical injuries
– pollution exposure
– Urban Sprawl
What’s good about cities?
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Transportation
• Greater use of mass transit and less use of
private automobiles
• Much more walking in some cities
transportation
• Energy efficiency of different forms
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Btus per person mile
Vanpool
1322
Eff. Hybrid
1659
Commuter rail
2996
Cars
3512
Air
3261
Fighting obesity
• City dwellers less likely to be obese
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St. John Newfoundland
Toronto
Vancouver
New York City
36%
16%
12%
20%
Energy
consumptionquad. BTU
Per household
Million BTU
Per household
member
Million BTU
City
4. 02
85.3
33.7
town
1.94
102.3
39.7
suburb
2.46
108.6
40.3
rural
2.13
95.1
37.8
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Alternatives to cities
• Suburbs
– Developed during 20th century
– People wanted space
• Loans, returning veterans
– Transportation: cars made living in one
place, working in another possible
• Westchester cty, NY: world’s first largescale suburban development
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Sprawl development
• Spreading outward of city and suburbs
• Low-density development
– Single family homes, large lots
– Auto dependent development
• Long distances to work
• Calgary, Alberta
Strip malls
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Zoning
• Laws that regulate land use in a city or town
are zoning laws (or regulations).
Smart Growth
• A new development paradigm
– Restoring center cities or older suburbs
– Transit and pedestrian oriented
– Mix of housing, retail, entertainment, other uses
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Urban considerations
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Energy use
Transportation
Cars vs. bikes vs pedestrian vs mass transit
Living space
Recycling
Lack of green space
• The American Dream
Urban Sprawl
Urban Sprawl: Causes & Effects
• (1) Automobiles and
Highway Construction
• (2) Living Costs
• (3) Urban Blight
• (4) Government Policies
(1) Automobiles and Highway
Construction
• 1950’s: the Interstate Highway System
• Commuting
• Work in the city and live in the suburbs
• Best of both worlds!
(2) Living Costs
• The American Dream
• More Land
• Larger House
• Privacy
• Lower taxes
• Overall, higher
standard of living
Levittown
• Excludes low income families
(3) Urban Blight
• The degradation of the built and social
environments of the city that often
accompanies the accelerated migration to
the suburbs
• A positive feedback loop
(3) Urban Blight
• People leaving cities
• Shrinking tax revenues
• City still must provide: police, fire, trash, sewage,
public transportation, and social services
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Cities reduce services
Crime increases
Infrastructure deteriorates
Built environment declines
(3) Urban Blight
• Suburban office parks
• Suburb to suburb commuting
• Can’t provide public transportation b/c too
spread out
• Commute around cities instead of through
them
• No need to go to the stores in a city
(3) Urban Blight
• Contributed to Racial Segregation
• “White Flight”
• Generated a disparity of opportunity
• Suburban Property tax revenues allow for
better schools
• Example: Busing in Boston 1974
(4) Government Policies
• Highway Trust Fund
– Highway Revenue Act 1956
• Federal gasoline tax to fund road construction/maintenance
– Induced Demand
• Who can Explain this Positive Feedback
mechanism?
(4) Government Policies
• Zoning
• Restrict land use to specific areas: residential,
industrial, commercial
• In the suburbs, where the traditional “Main
Street?”
•  new tool: multi-use zoning
(4) Government Policies
• FHA (1930’s)
• Federally Subsidized Mortgages
• Only wrote them in the financially low-risk
areas
Levittown (before)
Levittown (after)
Smart Growth
• Development of sustainable, healthy
communities
Mixed Land Use
Create walkable Neighborhoods
Create a Range of Housing Opportunities
Encourage community and stakeholder
collaboration in development decisions
Take advantage of compact building
design
Foster distinctive, attractive communities
with a strong sense of place
Provide variety of Transportation Choices
Preserve open space, farmland, natural
beauty, and critical environmental areas
Strengthen, direct development toward
existing communities
Make development decistions
predictable, fair, and cost-effective
Smart Growth
• Transit Oriented development
• Portland, OR
• Infill
• Urban Growth Boundaries
Foster distinctive, attractive communities with a strong sense
of place
Concentric Circle Model
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2.
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5.
Central business district (CBD)
Deteriorating transition zone
Worker’s homes
Middle-class suburbs
Commuter's zone
Sector Model
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2.
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7.
High-rent residential
Intermediate-rent residential
Low-rent residential
Education and recreation
Transportation
Industrial
Core (CBD)
Multiple-Nuclei Model
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2.
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9.
CBD
Wholesale, light manufacturing
Low-rent residential
Intermediate-rent residential
High-rent residential
Heavy manufacturing
Outlying business district
Residential Suburb
Industrial Suburb
Impacts of Urban Sprawl
Land and Biodiversity
Water
Human Health
and Aesthetics
Increased runoff
Contaminated drinking
water & air
Increased surface water
& groundwater pollution
Noise pollution
Increased use of surface
water & groundwater
Loss of cropland
Loss of forests &
grasslands
Loss of wetlands
Loss & fragmentation of
wildlife habitats
Increased wildlife road kill
Increased soil erosion
Sky illumination at night
Decreased storage of
Surface water &
groundwater
Traffic congestion
Increased flooding
Decreased natural
Sewage treatment
Impacts of Urban Sprawl
Energy, Air, and Climate
Economic Effects
Increased energy use
and waste
Higher taxes
Increased air pollution
Decline of downtown
business districts
Increased greenhouse gas
Emissions
Enhanced global warming
Warmer microclimate
(heat island effect)
Increased
unemployment
in central city
Loss of tax base in
central city
Transportation and Urban Development
• Determines where people live, where they go
to work and buy stuff, how much land is paved
and exposure to air pollution
• Cities grow up if they can’t grow out; more
prone to use mass transit
• Urban sprawl due to cheap gas and land and
highways; dispersed car-centered cities use
10x more energy
Motor vehicle concentration
• Ground transportation: individual (cars, etc) and mass
(buses and rail)
• U.S. has 35% of cars and trucks used for 98% of all
urban transportation
• Motor scooters - effort to change to electric
Drive alone 80%
• Riding bicycles;
less pollution and
dangerous and more
efficient than
walking
– bicycles available
for public use
– bike and ride
systems
Other 4%
Public transit 5%
Car pool 11%
Pros and Cons of Mass transit
• 3% mass transit use in U.S. to 47% in Japan
• 20% gasoline tax revenues to mass transit
• Rapid rail, suburban trains and trolley - efficient
at high population density
• High speed rail lines – replace planes, buses and
private cars; but require large government
subsidies
• Bus systems more flexible than rail systems but
efficient when full