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

• 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– 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– St. John Newfoundland 36%– Toronto 16%– Vancouver 12%– New York City 20%

City

Energy consumption- quad. BTU

4. 02

Per householdMillion BTU

85.3

Per household memberMillion BTU

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 large-

scale 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

• 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

• 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

1. Central business district (CBD)2. Deteriorating transition zone3. Worker’s homes4. Middle-class suburbs5. Commuter's zone

Sector Model

1. High-rent residential2. Intermediate-rent residential3. Low-rent residential4. Education and recreation5. Transportation6. Industrial7. Core (CBD)

Multiple-Nuclei Model1. CBD2. Wholesale, light manufacturing3. Low-rent residential4. Intermediate-rent residential5. High-rent residential6. Heavy manufacturing7. Outlying business district8. Residential Suburb9. Industrial Suburb

Impacts of Urban Sprawl

Land and Biodiversity

Loss of cropland

Loss of forests & grasslands

Loss of wetlands

Loss & fragmentation ofwildlife habitats

Increased wildlife road kill

Increased soil erosion

Human Healthand Aesthetics

Contaminated drinking water & air

Noise pollution

Sky illumination at night

Traffic congestion

Water

Increased runoff

Increased surface water & groundwater pollution

Increased use of surface water & groundwater

Decreased storage ofSurface water &

groundwater

Increased flooding

Decreased naturalSewage treatment

Impacts of Urban Sprawl

Energy, Air, and Climate

Increased energy useand waste

Increased air pollution

Increased greenhouse gas Emissions

Enhanced global warming

Warmer microclimate(heat island effect)

Economic Effects

Higher taxes

Decline of downtownbusiness districts

Increased unemploymentin 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

Drive alone 80%

Other 4%

Public transit 5%

Car pool 11%

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• Riding bicycles; less pollution and dangerous and more efficient than walking

– bicycles available for public use– bike and ride systems

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