Env Studies
– Miller Ch 11 – Human Population: Growth and Distribution
Intro – story of reduction in rate of population growth in Thailand in only 15 yrs
Significant increase in use of birth control by married women – 15% to 70% !!
Growth rate dropped from 3.2% to 0.8% - avg family had 6.4 children in 1971, dropped to 1.8 children by 2001.
11.1 – Factors affecting human population size pop change equation from before: change = (birth + immigration) – (death + emigration) look at some interesting birth and death rates
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Fig 11-2 note the big diff in developed ve developing countries… death rate about the same (8-10 per thousand), but the birth rate is way higher (2.5 times) in underdeveloped countries.
In developed countries, population is growing slo wly, in undeveloped, it’s growing rapidly. (fig 11-3)
Overall growth RATE of world peaked in 1963, but the population base is so huge that the number of people on the planet is growing quickly.
China and India make up, alone, more than 1/3 of world’s population (37%)
Global fertility rates
Very high number of births per woman in Africa, parts of Middle East, parts of S.
America
Relatively small changes in this rate can have dramatic impact upon overall expected world population (Fig 11-7)
Interesting chart (Fig 11-9) shows US growth trends over last 100 years…note baby boom in 1945-1964
Factors affecting birth and fertility rates
 More kids where they’re needed for work
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Less kids in more urbanized and developed countries
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Less kids when more expensive to raise and educate (like US)
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Less kids when women work (developed countries)
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Less kids where infant mortality is low, because not so many die
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Less kids when women marry at > 25
 Less kids when pension plans are good (they don’t need to support parents)
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Less kids when legal abortions are available
 Less kids when cultural norms don’t encourage lack of abortion or large families
Factors affecting death rates
Miller notes that recent rapid pop growth of world is due mostly due a decline in death rate, not rise in birth rate. Espec true in developing countries (fig 11-11)
Why lower death rates?
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More food
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Better nutrition
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Better medical & health technology
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Better sanitation & hygiene
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Safer water supplies (curtailed spread of many diseases)
2 main indicators are:
1. life expectancy (way up)
2. infant mortality rate (way down) side note – US does NOT have lowest infant mortality rate in the world…Miller suggests this is due to : poor health care for poor women drug addiction in mothers high birth rate among teenagers (who have babies w/ high death rate)
11-2 Population Age Structure
Fig 11-12 shows 4 diff growth scenarios
– rapid, slow, Zero, and negative
Huge diff between developed and underdeveloped countries, fig 11-13
Miller goes over the edge once again, claiming that the baby boomers are
“forcing” the Gen Xers to pay higher income, health-care, and Social Security taxes….”this could cause resentment and conflicts between the two generations”
11-3 solutions: influencing population size population size and migration only a few countries allow large amounts of immigration
– US, Canada, Australia.
Controversy over reducing births:
Some think population growth is of no concern. Others think it is of major concern. Miller suggests looking at a possible “cultural carrying capacity” of
Earth. What is cultural carrying capacity?
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Cultural carrying capacity is diff than simple carrying capacity, takes into account the lifestyles of people. Assumption is that the higher the lifestyle, the less people can be s upported or “carried” by the environment.
Economic development and reduced birth rates
Miller introduces a theory of demographic transition:
“as countries industrialize, first death rates, then birth rates, decline” this happens in 4 stages: (see Fig 11-18)
1. preindustrial
– harsh conditions, high birth rates, high death rates, ZPG
(zero population growth)
2. transitional stage – industrialization begins, death rates drop, birth rates stay high, pop grows fast (3%/yr)
….. this is where many “developing” countries are today
…SE Asia, Africa, Latin America
3. industrial stage – birth rate drops, closer to death rate, pop grows but at slower rate . “Most developed countries are now in this stage.”
4. postindustrial stage
– birth rate drops and matches death rate, reach ZPG, then birth rate doesn’t even keep pace with death rate, and total population actually shrinks. 35 countries, mostly European, have entered this stage, and have only 13% of Earth’s population.
Miller discusses family planning as one way to reduce birth rates…
And empowering women as another way to reduce birth rates.
Economic rewards and penalties for reducing birth rates
Experts say “most couples in developing countries want 3-4 children” (like the US baby boom post WW II)
, which is above the “replacement-level fertility rate”
Some countries, including China, penalize couples who have more than 1-2 children. Incentives are varied:
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raise taxes for those who have more children
 charge add’l fees
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eliminate income tax deductions coercive methods have been used in China to reduce “out of control” growth rate
11-4 Case Studies: Slowing Pop growth in India and China
India
Site of world’s first national family planning program, back in 1952, when it had
400 million people. India is now the 2 nd most populous country in world, with 1 billion people.
India is still one of world’s poorest countries, avg annual income is $440/person.
40% of pop suffers from malnutrition
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results of India’s efforts are “disappointing”…women still have an avg of 3.2 children, “because most couples believe they need many children to do work and care for them in old age”.
only 43% of Indian couples practice birth control
China
China has dramatically cut fertility
– 5.7 children per woman in 1972, now down to 1.8 children
How did t his happen? Through the “most strict pop control program in the world”.
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Couples encouraged to have 1 child only, and receive many benefits: o More food o Larger retirement pensions o Better housing o Free medical care o More salary o Free school tuition for one child
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81% of married couples use birth control
Paradoxically, perhaps one of the reasons China has been so successful is that it is a dictatorship, and has been able to impose strict rules upon people
11-5 cutting global pop growth
United Nations is encouraging this through a series of steps
Several countries have shown that they can drop to “replacement-level” fertility rates in only 15-30 years – Japan, S.Korea, Iran, China
What works:
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family planning (birth control)
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reduce poverty
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elevate status of women
11-6 pop distribution: urbanization (see Fig 11-20) arbitrary def’n of areas: urban = town > 2500 people rural = town < 2500 people degree of urbanization defined as % of pop living in urban areas urban areas growing rapidly, through 2 mechanisms:
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natural increase (birth > death)
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immigration, typically from rural areas
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patterns of urbanization
5 trends:
1. urban pop is increasing (from 1850-2001, incr from 2% to 46% !)
2. number of large cities is increasing (incl doubling of megacities from 8-16 over only 15 years)…. what’s a megacity? 10,000,000 people
3. urbanization increasing rapidly in developing countries
4. urban growth much slower in developed countries (those are already 75% urbanized)
5. poverty becoming more urbanized case study: Mexico City
– 18,000,000 people, world’s second most populous city
Big problems:
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air pollution
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high unemployment
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noise
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high crime rate
1/3 of residents live in slums, w/ no running water or electricity
8,000,000 people with no sewer system, so waste is left out in open, attracting rats, flies….when excrement dries, wind picks it up and spreads it, along with salmonella bacteria and hepatitis
Air pollution is very bad, in part because city is surrounded by mountains that hold it in place. “breathing the city’s air is said to be equivalent to smoking 3 packs/day ”
Some of the things the city is trying to do to improve the situation:
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ban cars from central city
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remove old taxis
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use LPG gas for buses and trucks
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plant 25,000,000 trees
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buy land for green space
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phase out leaded gas & incr catalytic converters
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enforce industrial standards city fails to meet minimum air-quality standards 300 days / year urbanization in US from 1800 to 2001, percentage of US pop in urban areas grew from 5% to 75% occurred in 4 phases:
1. migration from rural areas to large central cities (e.g., half of US lives in cities > 1 million people; 75% in cities of > 50,000)
2. migration from central cities to suburbs (half of US lives in suburbs)
3. migration from North and East to South and West (most of US pop incr. is in south and West)
4. migration from urban areas back to rural areas
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major urban problems in US
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deteriorating services
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aging infrastructure (streets, bridges, sewers, housing, schools)
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reduced finances to fund improvements
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rising poverty urban sprawl is a very big problem in US.. defined as “low-density development on the edges of cities”
Fig 11-23 shows “undesirable impacts” of urban sprawl…
11-7 Urban resource and environmental problems environmental disadvantages of urbanization
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urban dwellers co nsume 75% of Earth’s resources while occupying only
4% of land
 urban dwellers produce most of world’s pollution, and this pollution negatively impacts the urban area
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most of worlds cities are not self-sustaining
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high population densities encourage: o spread of infectious disease o physical injury o high crime o excessive noise
11-8 transportation and urban development transportation planning and land use are closely linked key decisions must be made concerning:
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where people live
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travel to work
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how much land is paved over
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how much air pollution is generated concept of compact city (high pop density) encourages walking, bicycling, mass transit. This is the typical European city. (maybe NYC too?)
Miller claims “dispersed car-centered cities use up to 10 times more energy per person for transportation than more compact cities”.
He states that walking and bicycling make up 40-50% of all land-based trips in
Europe (!)
Contrast that with US, where 95% of all trips are by car, 3% mass transit, and just 2% walking….
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I nteresting stat: US has only 4.7% of world population, but 35% of world’s vehicles! Wow…..
Another stat…76% of Americans drive to work alone.
Can auto use be curtailed?
Well…some suggestions by Miller, akin to those he made in the chapter about toxicolog y. Try a “user-pays” approach, where the “estimated harmful costs” of driving are added as add’l taxes that could then be used to improve mass transit, etc.
Miller says that these “hidden costs of driving” are taken into account in Europe and Japan….if we did the same thing here, it would generate another $5-$7 in tax per gallon…huge increase. This would spawn a major drive toward more fuelefficient cars.
Alternatives to the auto?
Motor scooters
Bicycles – often faster than cars when distances are less than 5 miles
Mass transit rail systems in cities
Rapid rail systems between urban areas
Buses
11-9 solutions: making urban areas more livable and sustainable land-use planning – economic growth is often encouraged because property taxes on existing property cannot sustain the increased need for services such as schools, police, fire, water, sewer, etc. this economic growth leads to many problems, sprawl, etc.
Smart Growth
This concept uses zoning ordinances to:
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prevent urban sprawl
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direct certain types of growth in certain directions (industry, residence, etc)
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protect environmentally sensitive areas
 develop urban areas in more “sustainable” ways
Brownfields initiatives are good example of this…re-use existing industrial sites, or use them in more sensible manner for new housing, etc., rather than just keep moving ever outward, into the suburbs
Miller cites this as a return to some 19 th -century town-planning practices:
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shopping within walking distance of home
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create enough pop density to support mass transit
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more open space
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how do we make cities more green?
Planners suggest that our problem is not that urbanization is bad, but that we need to make these urban areas more desirable and livable. Good point….
So Miller suggests designing toward “ecocities”, those that are environmentally sustainable.
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Prevent pollution and reduce waste
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Use energy more efficiently
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Recycle and re-use more
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Use solar-powered living machines (wastewater garden , Fig 14-32)
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People-oriented, not car-oriented
His vision of the ecocity is pleasant:
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All buildings, etc are energy-efficient
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Trees and plants abound
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Abandoned lots and brownfields are cleaned up and redeveloped
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Much food comes from nearby organic farms, solar greenhouses, community gardens, and individual gardens on rooftops, in yard, and window boxes.
He says this is NOT a futuristic dream, but is happening right now:
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Curitiba, Brazil
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Waitlakere City, New Zealand
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Chattanooga, TN
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Copenhagen, Denmark
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Portland, OR
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Davis, CA
Hmmmmm……
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