ENVIRONMENTAL SCIENCE

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ENVIRONMENTAL SCIENCE
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CHAPTER 6The Human Population and Urbanization
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Core Case Study Are There Too Many of Us? (1)

• 6.8 billion people
• 82 million more each year
• 2050 9.5 billion people at current growth rates
• Most growth in low-income and middle-income
  countries
• Enough resources for growing population?

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Core Case Study Are There Too Many of Us? (2)

• Negative viewpoint
• 20 currently lack basic necessities
• Declining conditions increase death rate
• Increased resource use
• Increased environmental degradation
• Positive viewpoint
• Technological solutions will increase carrying
  capacity
• Growing population a valuable resource

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6-1 How Many People Can the Earth Support?

• Concept 6-1 We do not know how long we can
  continue increasing the earths carrying capacity
  for humans without seriously degrading the
  life-support system that keeps us and many other
  species alive.

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Human Population Explosion

• Exponential growth (J-curve) in past 200 years
• Three major reasons
• Ability to expand into diverse habitats
• Emergence of agriculture
• Sanitation systems and control of infectious
  diseases decreased death rates

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How Long Can the Human Population Grow

• Rate slowing, but still exponential
• Uneven global growth
• No population can grow indefinitely
• 2050 9.5 billion people at current growth rates
• Most growth in developing countries, least likely
  to cope

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6-2 What Factors Influence the Size of the Human
Population?

• Concept 6-2A Population size increases through
  births and immigration and decreases through
  deaths and emigration.
• Concept 6-2B The average number of children born
  to women in a population (total fertility rate)
  is the key factor that determines the population
  size.

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Population Change

• Population change
• (births immigration) - (deaths emigration)
• Demographers look at birth rates and death rates
• 2009
• China, 1.3 billion people
• India, 1.1 billion people
• USA, 306 million people

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Number of Children

• Fertility rates affect population size and growth
  rate
• Total fertility rate (TFR)
• 1950-2009 Global TFR fell to
• 1.6 from 2.5 in developed countries
• 2.8 from 6.5 in developing countries

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Case Study The U.S. Population Is Growing Rapidly

• Quadrupled in 100 years, despite oscillations in
  TFR
• Baby boom High TFR
• Current births outnumbering deaths and legal
  immigration
• Growing faster than other developed countries
• 2050 estimate 439 million

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Factors Affecting Birth Rates (1)

• Importance of children as part of labor force
• Cost of raising and educating children
• Availability of retirement systems
• Urbanization
• Educational and employment opportunities for
  women

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Factors Affecting Birth Rates (2)

• Average marriage age
• Availability of legal abortion and reliable birth
  control methods
• Religious beliefs, traditions, cultural norms

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Factors Affecting Death Rates

• Population growth is also response to decline in
  crude death rate
• Life expectancy and infant mortality rate
  important indicators of overall health
• Average life expectancy increased
• Infant mortality barometer of a societys
  quality of life

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Migration

• Migration driven by economic desires
• Other reasons
• Religious persecution
• Political oppression
• Ethnic conflicts
• Wars
• Environmental degradation

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Case Study The United States - A Nation of
Immigrants (1)

• Immigration legal and illegal 39 population
  growth
• 18201960 Most immigrants European
• Since 1960
• Latin America 53
• Asia 25
• Europe 14

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Case Study The United States - A Nation of
Immigrants (2)

• Opponents of immigration
• Stabilize population sooner
• Reduce growing environmental impact
• 60 of population favor reducing immigration
• Proponents of immigration
• Important historical role
• Do menial jobs and pay taxes
• Add cultural vitality
• Replace retiring baby boomers

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6-3 How Does a Populations Age Structure Affect
Its Growth or Decline?

• Concept 6-3 The numbers of males and females in
  young, middle, and older age groups determine how
  fast populations grow or decline.

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Age Structure

• Distribution of population
• Prereproductive
• Reproductive
• Postreproductive
• Country with many young people grows rapidly
• Country with many older people will decline
• Developing countries gt30 under 15 years old

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Age Structure Predicts the Future

• 36 of U.S. population baby boomers
• Graying of America
• Over time increasing percentage of older baby
  boomers
• Changes the economy

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Declines Occur in Aging Populations

• Baby bust or birth dearth TFR below 1.5
  children per couple
• Labor shortages
• Strain on governments for public services
• Fewer taxpayers

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Rising Death Rate The AIDS Tragedy

• Disrupts social and economic structure
• Removes productive young adults
• 1981-2008 27 million deaths
• Eight African countries 1639 infected adults
• Life expectancy 3040 years

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6-4 How Can We Slow Human Population Growth?

• Concept 6-4 We can slow population growth by
  reducing poverty, encouraging family planning,
  and elevating the status of women.

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Stages of Demographic Transition

• Preindustrial
• Transitional demographic trap
• Industrial
• Postindustrial

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Family Planning (1)

• Birth spacing, birth control, health care
• Increased availability of contraception
• 55 drop in TFR of developing countries
• Developing countries
• Almost half pregnancies unplanned
• Often lack access to family planning

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Family Planning (2)

• Invest in family planning
• Reduce poverty
• Elevate the social and economic status of women

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Empowering Women Can Slow Population Growth (1)

• Women tend to have fewer children if they
• Are educated
• Control their own fertility
• Have a paying job outside the home
• Do not have their rights suppressed

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Empowering Women Can Slow Population Growth (2)

• Women do almost all domestic housework and
  childcare
• Women do 60-80 of agriculture, wood gathering,
  water hauling
• Globally, women do 2/3 of all work for 10 of
  income

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Empowering Women Can Slow Population Growth (3)

• Illiterate woman 64 of worlds population, 70
  of the poor
• When daughters considered less valuable, not sent
  to school
• Poor conditions for women leads to environmental
  degradation

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Case Study Slowing Population Growth in China (1)

• One-child families
• Halved birth rate and drastically reduce TFR
• Improved quality of life
• Strict family planning
• Sons still preferred gender imbalance

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Case Study Slowing Population Growth in China (2)

• Population rapidly aging
• Rapidly growing economy
• Larger middle class increases resource
  consumption and waste
• Sustainable economic plan needed to avoid
  environmental degradation

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Case Study Slowing Population Growth in India

• Tried to slow population growth for five decades
• Most populous country in 2015
• Problems increase with growing population
• Poverty
• Malnutrition
• Environmental degradation
• Growing middle class resource consumption

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6-5 What Are the Major Urban Resource
Environmental Problems?

• Concept 6-5 Most cities are unsustainable
  because of high levels of resource use, waste,
  pollution, and poverty.

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Urban Living

• Half the world lives in urban areas
• 79 of Americans live in cities
• 50 of world population lives in cities
• Urban areas continue to grow
• Natural increase
• Immigration

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Major Trends in Urban Growth

• Proportion of urban global population growing
• Number and sizes of urban areas mushrooming
• Rapid increase in urban populations in developing
  countries
• Urban growth slower in developed nations
• Poverty increasing

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Case Study Urbanization in the United States (1)

• 18002009 urban population increased from 5 to
  79
• Migration patterns
• Rural areas to large cities
• Large cities to suburbs and smaller cities
• Cities and suburbs to rural areas
• North and East to South and West

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Case Study Urbanization in the United States (2)

• Better working and housing conditions compared to
  the past
• Improved environmental conditions
• Problems in urban areas
• Aging infrastructure
• Budget problems

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Urban Sprawl Causes

• Prosperity
• Ample and affordable land
• Automobiles
• Cheap gasoline
• Poor urban planning

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Urban Sprawl Problems

• Increased automobile use
• Decreased energy efficiency
• Destruction of cropland, forests, wetlands
• Economic deaths of some cities

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Advantages of Urbanization (1)

• Economic development
• Innovation
• Education and jobs
• Technological advances
• Longer life spans

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Advantages of Urbanization (2)

• Better social and medical services
• Recycling more feasible
• Biodiversity increased
• Increased energy efficiency

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Disadvantages of Urbanization (1)

• Unsustainable systems
• Lack of vegetation
• Water problems
• Pollution and health problems

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Disadvantages of Urbanization (2)

• Noise pollution
• Climate and artificial light
• Urban heat islands
• Light pollution

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Fig. 6-15, p. 111
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Inputs
Outputs
Energy
Solid wastes
Waste heat
Food
Air pollutants
Water
Water pollutants
Raw materials
Greenhouse gases
Manufactured goods
Manufactured goods
Noise
Money
Wealth
Information
Ideas
Fig. 6-15, p. 111
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Fig. 6-16, p. 112
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Permanent damage begins after 8-hour exposure
Noise Levels (in dbA)
85
0 10 20 30 40
50 60 70 80 90
100 110 120 130 140 150
Earphones at loud level
Normal breathing
Quiet rural area
Rainfall
Vacuum cleaner
Lawn mower
Rock music
Boom cars
Military rifle
Normal conversation
Chain saw
Air raid siren
Whisper
Quiet room
Average factory
Thunderclap (nearby)
Fig. 6-16, p. 112
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Urban Poor in Developing Countries

• Slums
• Shantytowns and squatter settlements
• Lack of basic services

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Case Study Mexico City (1)

• Large population
• Severe noise, water, and air pollution
• 50 unemployment
• 100,000 premature deaths per year

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Case Study Mexico City (2)

• 3 million without sewer
• Fecal snow
• Geography contributes to air pollution
• Progress tree planting and lower air pollution

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6-6 How Does Transportation Affect Urban
Environmental Impacts?

• Concept 6-6 In some countries, most people live
  in dispersed urban areas and depend mostly on
  motor vehicles for their transportation.

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Cities Can Grow Outward or Upward

• Compact cities
• Transportation by walking, biking, or mass
  transit
• Hong Kong, Tokyo
• Dispersed cities
• Transportation by automobile
• Most American cities

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Automobiles

• Gas guzzlers
• 40,000 people per year die from auto accidents in
  the United States
• Worlds largest source of air pollution
• Lead to urban sprawl and congestion

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Reduce Automobile Use

• User-pays system
• Full-cost pricing
• Tax revenues to finance mass transit, bike paths,
  sidewalks
• High gasoline tax unlikely
• Need to discourage automobile use

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Alternatives to Cars

• Bicycles
• Mass transit systems in urban areas
• Bus systems
• Rapid rail

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6-7 How Can Cities Become More Sustainable and
Livable?

• Concept 6-7 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.

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Environmentally Sustainable Cities

• Smart growth
• Ecocities
• Use renewable energy as much as possible
• Build and design people-oriented cities
• Use energy and matter efficiently
• Prevent pollution and reduce waste
• Recycle, reuse, and compost
• Protect and encourage biodiversity
• Promote urban gardens and farmers markets
• Zone for environmentally stable population levels

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Case Study Curitiba, Ecocity in Brazil (1)

• Curitiba ecological capital of Brazil
• Inexpensive, efficient mass transit
• High-rise apartments near bus routes, mixed-use
  structures
• Bike and pedestrian paths

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Case Study Curitiba, Ecocity in Brazil (2)

• 1.5 million trees planted
• Recycling
• Many services for the poor
• Emphasis on ecological awareness, health, literacy

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Three Big Ideas from This Chapter - 1

• The human population is increasing rapidly and
  may soon bump up against environmental limits.

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Three Big Ideas from This Chapter - 2

• We can slow human population growth by reducing
  poverty, encouraging family planning, and
  elevating the status of women.

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Three Big Ideas from This Chapter - 3

• Most urban areas, home to half of the worlds
  people, are unsustainable, but they can be made
  more sustainable and livable within your lifetime.