World Population Distribution Trends
- Proportion of population living in urban areas is increasing.
- Number of large cities is increasing.
- Urban populations in developing countries have more people than Europe, the Americas, and Japan combine--and this population is growing.
- Developed countries have a slowly growing urban proportion, but are heading toward 85% by 2025.
- Poverty is moving from the rural to the urban areas.
US Population Shifts Since 1800
- Shift to large central cities
- Shift from large cities to small cities and suburbs
- Shift from north/east to south/west
- natural increase
- immigration - mostly from rural areas
- pulled - by jobs, income, culture, health care, trade, freedom, etc.
- pushed - by poverty, lack of land, lack of jobs, famine, war
Urban Environmental Problems
- vegetation -
- Cities have few trees and shrubs, which could improve the environment by absorbing air pollution, producing oxygen, cooling the air, muffling noise, providing wildlife habitats, and controlling stormwater and erosion.
- Cities produce little of their own food, which would recycle waste (composting) and reduce the extra resource use for growing and transporting food from outside.
- water runoff -
- Concrete and asphalt cause rapid runoff from precipitation and block the water from penetrating the soil. Stormwater is frequently contaminated by oil, salt, toxic liquids, fertilizers and pesticides, and since can't be absorbed by the ground, it must enter the seres and storm drains, which may overflow.
- Most cities are build on floodplains and/or near the sea, which increases the chance of flooding.
- heat islands and dust domes -
- urban heat island
- Buildup of heat in the atmosphere above an urban area. This heat is produced by the large concentration of cars, buildings,f actories, and other heat-producing activities.
- dust dome
- Dome of heated air that surrounds an urban area and traps pollutants, especially suspended particulate matter.
- solid waste disposal - High concentration of people -> a lot of waste with no place to put it.
- air pollution - High concentration of pollutant output (mostly from fossil fuels) combined with the heat trap effect -> high concentration of air pollutants
- noise pollution - Lots of people and machinery -> noise pollution
- human health -
- Inadequate sewage systems, close proximity of large numbers of people -> fast spread of disease
- High concentration of pollutants -> poor health
- land conversion - Increasing value of land near cities, expanding city populations -> loss of fertile farmland and wildlife habitats
- social disruption -
- Farmers forced to sell land
- Transportation lanes congested
- Utilities and services overwhelmed
Positive Effects of Urbanization
- Less land used for more people -> more land saved for wildlife
- Recycling more feasible; recyclable material is easy to collect
- Population growth reduced by environmental pressure
- Easier to educate public because people are together
Transportation Options - individual
- energy efficient--bicycles are most energy efficient form of transportation
- inexpensive--walking is free
- faster than cars in urban traffic
- exclusive zones increase business
- not as useful for trips longer than 5 miles, especially past 10 mi
- seen as backward
- powers much of the economy
- causes air pollution
- uses up fossil fuels
- leads to military support of repressive regimes in the Middle East
- traffic jams--lost time/money/gas
- freeways cause social disruption
- increased noise and stress
Transportation Options - mass
- energy efficient where population is concentrated
- less pollution
- use less land
- high start-up cost
- only useful in densely populated areas
- cheaper than either highway or heavy-rail system
- operating costs are lower than bus system; can link cars
- cleaner and quieter than buses
- does not require exclusive right-of-way
- less pollution than either buses or cars
- high startup cost compared to bus system
- faster than airplane
- more efficient than car or plane
- expensive to run and maintain
- must operate on heavy traffic routes to be profitable
MAGLEV - magnetic track - train doesn't touch track
- faster than high-speed rail
- little noise
- low maintenance
- can be elevated over existing rights-of-way
- under development--only prototypes available
- high construction costs
- questionable safety
- medical effects of magnetic fields ???
Sandia train - carries electromagnetic coils onboard
- all advantages of MAGLEV
- doesn't require special track--can use existing track
- cheaper than MAGLEV
- Flexible - routes can be changed overnight if necessary to suit traffic demands
- lower startup and operating costs than heavy-rail systems
- not as efficient as rail systems
- not as fast as rail
- not as reliable as rail; can get caught in traffic
- since it needs low fares, often costs more to operate than it brings in
- only cost effective when buses are full
Positive Feedback Loop Policies for Increasing Automobile Dependence
- Four times more federal gasoline tax money allocated to highways than to mass transit -> states and cities invest in highways instead of mass transit
- Employees can deduct parking expenses from taxes, but no gains for mass transit users, bicyclers, or walkers -> encourage driving commuters
- Government subsidies for motor vehicles & autoroutes -> increase in motor vehicle use
Possible Negative Feedback Loop Policies for Decreasing Automobile Dependence
- Raise gasoline tax to cover all road building and maintenence cost - users pay
- Invest in mass transit and exclusive city pathways for pedestrian and cycling traffic
- Offer transportation money to employees instead of tax benefits to employers who offer parking
- ecological land-use planning
- Method for deciding how land should be used; development of an integrated model that considers geographical, ecological, health, and social variables
- conventional land-use planning
- Method for deciding how land should be used; encourages economic growth without restriction
Local governments can control the rate of development by zoning and limiting the number of permits and utility hookups.
Obstacles to Economic Land-Use Planning
- high costs
- local officials concentrate on short-term gains
- difficult to get cooperation among neighboring municipalities
The urban infrastructure in the US is getting worn out. It wasn't high quality work in the first place, it's old, and it's been neglected for decades. The money for fixing up the infrastructure isn't there, funding gets cut every year, and citizens are opposed to raising taxes.
- If the municipality responds to an increase in cars by accomodating those cars, even more cars will come. One way to counteract that loop is to refuse to expand the automobile infrastructure. A better way is to ban cars from city centers.
We can improve urban life by:
- giving up big lawns
- building homes in small, dense clusters to leave open community space available
- developing a town center to focus civic life
- planting trees instead of cutting them down
- discouraging dependence on automobiles and encouraging walking and cycling
Curitiba, Brazil is a city of 2.1 million. As a densely populated area, it doesn't have big lawns. Zoning regulations concentrate homes along transportation routes and designate parks in flood-prone areas. An efficient bus system replaces the car. The city has 1.5 million trees, and none may be cut down without being replaced by two more. The downtown area is off-limits to cars, and abandoned factories have been converted to recreational facilities. Curitiba has implemented all five approaches.
- No, I'm not aware of any mass transit possibilies for Warren. It's such a car-based sprawl of a town; it would take a lot of effort to get people to walk even a mile or two to trolley stops.
- I am not familiar with zoning procedures except to know that the zoning is very poorly planned. Everything's sprawl.
- I am depressed by urban sprawl and excited about urban renewal.
- I feel that growth that improves and not just expands the city is good.
- I support pretty much everything suggested in this chapter. I wish these ego-centric politicians would pay attention.