Sustainable Cities

Chapter 22

22-1 What Are the Major Population Trends in Urban Areas?

Concept 22-1 Urbanization continues to increase steadily and the numbers and sizes of urban areas are growing rapidly, especially in developing countries.

Half of the World’s People Live in Urban Areas

Urbanization • The creation and growth of urban areas• Measured as the percentage of people living in an

urban area

Urban growth• The rate of increase of urban areas• Natural increase (births over deaths)• Immigration from rural areas

Half of the World’s People Live in Urban Areas

Immigration from rural areas as a result of…• People pulled to urban areas from rural areas:• In search of jobs, food, housing, education, better

health care, entertainment, etc.

• People pushed from rural areas to urban areas:• Poverty, lack of land for growing food, declining

agricultural jobs, war, famine, etc.

Four major trends:1. Proportion of global population living in urban areas is

increasing• 30% urban in 1950, 60% urban by 2030

2. Urban areas are expanding rapidly in number and size• 1970: 2 urban areas with population of 10+ million• 2025: 37 urban areas with population of 10+ million

3. Urban growth is much slower in developed countries than in developing countries

4. Poverty is becoming increasingly urbanized; mostly in developing countries• One billion people living in slums worldwide

Half of the World’s People Live in Urban Areas

Megacities – cities with 10 million or more people Hypercities – cities with 20 million or more people

Half of the World’s People Live in Urban Areas

Case Study: Urbanization in the United States

Four phases between 1800 and 2008 that led to urban population growing from 5% to 79%:1. Migration from rural areas to large central cities

2. Migration from large central cities to suburbs and smaller cities• Half of all urban Americans live in suburbs

3. Migration from North and East to South and West• 80% of U.S. pop. growth occurred in South and West

4. Migration from cities and suburbs to developed rural areas

Case Study: Urbanization in the United States

8 in 10 Americans live in urban areas. About 48% of Americans live in consolidated

metropolitan areas.

Urban Sprawl Gobbles Up the Countryside

Urban sprawl • Growth of low density development on the edges of

cities, thus eliminating agricultural and wild lands

Contributing factors to urban sprawl in the U.S.:1. Ample land to spread out

2. Government loan guarantees stimulate growth

3. Low-cost gasoline; highways encourage vehicle use

4. Tax laws encouraged home ownership

5. State and local zoning laws

6. Multiple political jurisdictions: poor urban planning

As they grow and sprawl outward, urban areas merge to form a megalopolis.• Bowash runs from

Boston, Massachusetts to Washington, D.C.

Urban Sprawl Gobbles Up the Countryside

Natural Capital Degradation: Urban Sprawl

22-2 What Are the Major Urban Resource and Environmental Problems?

Concept 22-2 Most cities are unsustainable because of high levels of resource use, waste, pollution, and poverty.

Urbanization Has Advantages

Cities are centers of economic development, jobs, commerce, education, and transportation.

Urban populations are generally healthier, with better access to medical care, family planning information, education, and social services.• The poor do not have the same access.

Recycling is more feasible and environmental protection is better supported.

People concentrated in an area preserves biodiversity and wildlife habitats.

Huge ecological footprints, not self-sustaining• Urban areas are only 2% of Earth’s surface but

consume 75% of the resources.

Urbanization Has Disadvantages

Urbanization Has Disadvantages

Lack vegetation Water problems• Very high demand• Deprives surrounding rural areas• Increase flooding from storm runoff

Concentrate pollution and health problems• Pollution levels are greater b/c they cannot be

dispersed and diluted as easily

• CO2 and NO2 emissions from cars

• More easily spread infectious diseases

Urbanization Has Disadvantages

Excessive noise• Noise pollution – unwanted, disturbing, or harmful

sound that impairs hearing, causes stress, hampers concentration/efficiency, or causes accidents.

Different climate and experience light pollution• Heat generated and solar energy absorbed• Similar to noise, too much light can be harmful

Life Is a Desperate Struggle for the Urban Poor in Developing Countries

Extreme poverty forces hundreds of millions of people to live in slums, squatter settlements, or shantytowns where adequate water supplies, sewage disposal, and other services do not exist.• According to a U.N. study, in 2006 about 1 billion

people worldwide lived in these conditions.

22-3 How Does Transportation Affect Urban Environmental Impacts?

Concept 22-3 A combination of plentiful land, inexpensive fuel, and expanding networks of highways in some countries has resulted in dispersed cities whose residents depend on motor vehicles for most transportation.

Cities Can Grow Outward or Upward

Land availability determines whether a city must grow vertically or if it can spread out horizontally• Compact cities (Hong Kong, China; Tokyo, Japan)

• Dense development, high-rise buildings, mass transit

• Dispersed cities (U.S. and Canada)

• Plentiful land, cheap gasoline, network of highways, dependence on cars

The urban sprawl of most U.S. urban areas is a prime example of car-centered dispersed cities.• With just 4.6% of the world’s population, the U.S. has

almost one-third of the world’s cars.• Passenger vehicles are used for 98% of all transportation.• If Americans doubled their use of mass transit from 5% to

10%, this would reduce U.S. dependence on oil by 40%.• Mass transit: not an option in most cities as a result of the

dispersed nature of the growth

Cities Can Grow Outward or Upward

Motor Vehicles Have Advantages and Disadvantages

Advantages• Mobility and convenience• Status symbol• Jobs in: production and repair of vehicles and parts,

supplying fuel, building roads

Disadvantages• Largest source of outdoor air pollution• Accidents: death and injury • Helped create urban sprawl• Traffic congestion

Reducing Automobile Use Is Not Easy, but It Can Be Done

Full-cost pricing: higher gasoline taxes to cover the harmful costs of driving

Tolls on roads, tunnels, and bridges into major cities Raise parking fees Car-sharing

Some cities are promoting alternatives to cars:• bicycles, mass transit rail systems, buses, rapid-rail

system between urban areas

Trade-Offs: Bicycles, Advantages and Disadvantages

Trade-Offs: Mass Transit Rail, Advantages and Disadvantages

Trade-Offs: Buses, Advantages and Disadvantages

Trade-Offs: Rapid Rail, Advantages and Disadvantages

22-4 How Important Is Urban Land Use Planning?

Concept 22-4 Urban land-use planning can help to reduce uncontrolled sprawl and slow the resulting degradation of air, water, land, biodiversity, and other natural resources.

Urban Land-Use Planning

Land-use planning • Encourages future urban sprawl • Funded by property taxes• Goal is economic development • Often environmentally destructive

Zoning – Parcels of land are designated for specific uses• Favors high priced projects• Discourages innovation

Smart Growth Works

Smart growth can help control growth patterns discourage urban sprawl, reduce car dependence, and protect ecologically sensitive areas.

22-5 How Can Cities Become More Sustainable and Livable?

Concept 22-5 An ecocity allows people to: choose walking, biking, or mass transit for most transportation needs; recycle or reuse most of their wastes; grow much of their food; and protect biodiversity by preserving surrounding land.

Cluster Development

Conventional housing development• Bulldoze woods or farmland

and build rows of houses on uniform sized lots

Cluster development• Houses concentrated on one

portion of the land with the rest used for commonly shared open space.• Cheaper• More aesthetically pleasing• More open recreational space

There is a growing movement to create mixed-use villages and neighborhoods within urban areas where people can live, work and shop close to their homes.

New urbanism• Walkability• Mixed-use and diversity• Quality urban design• Environmental sustainability• Smart transportation

New Urbanism is Growing

The Ecocity Concept:Cities for People Not Cars

Use parts of the new urbanism ideals to redesign entire cities. Ecocities or green cities:• Allows people to walk, bike, or take mass transit for

most of their travel• Use renewable energy resources • Recycle and purify water• Use energy and matter resources efficiently• Prevent pollution and reduce waste• Recycle, reuse and compost municipal waste• Protect and support biodiversity• Urban gardens; farmers markets