Environmental Science: Toward a Sustainable Future Richard T. Wright

1
Environmental Science Toward a Sustainable
Future Richard T. Wright
Chapter 5

• The Human Population Dimensions
• PPT by Clark E. Adams

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Human Population Growth and the Consequences

• Human population expansion and its cause
• Different worlds
• Consequences of population growth and affluence
• Dynamics of population growth

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Human Population Expansion and Its Cause

• Reasons for the patterns of growth
• Biotic potential exceeds environmental
  resistance birth rates exceed death rates
• There are 6.3 billion people on Earth
• If each one stood up, pronounced their name, and
  sat down
• It would take 600 years to complete roll call
• By 2025 it will take 1,000 years to complete this
  exercise

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World Population over the Centuries
9,000 human beings added to the planet every hour
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Reasons for the Human Population Explosion

• Causes of disease recognized
• Improvements in nutrition
• Discovery of antibiotics
• Improvements in medicine
• Increase in number of women who actually reach
  child-bearing age
• Short doubling times in some countries

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Changing Human Survivorship Curves Went from B
to A
A
Survival
B
Age
Birth
Death
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World Population Growth and Absolute Growth
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Population Projections Based on Different
Fertility Assumptions
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Average Number of Children, Grandchildren, and
Great Grandchildren

• America
• West Germany
• Africa

• 14
• 5
• 258

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Different Worlds

• Rich nations, poor nations
• Population growth in rich and poor nations
• Different populations, different problems

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Human Poverty Index for Developing Countries
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Economic Categories Based on Per Capita Gross
National Income (see Fig. 5-4)

• High-income, highly developed, industrialized
  countries
• United States, Japan, Canada
• Average GNI per capita 26,710
• Middle-income, moderately developed countries
• Latin America, South Africa, China
• Average GNI per capita 1,850

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Economic Categories Based on Per Capita Gross
National Income (see Fig. 5-4)

• Low-income, developing countries
• Western and central Africa, India, central Asia
• Average GNI per capita 430

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Disparities

• Developed countries
• 16 of the worlds population
• Control 81 of the worlds wealth
• Low-income developing countries
• 41 of the worlds population
• Control 3.4 of the worlds gross national income
• Difference in per capita income 62 to 1!

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Population Increase in Developed and Developing
Countries
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Population Data for Selected Countries (Table 5-3)
Country Total Fertility Rate Doubling Time (Years)
World 2.8 54
Developing Countries 3.5 37
Developed Countries 1.5 700
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Different Populations, Different Problems

• Human pressure on the environment caused by three
  factors
• Population size
• Affluence
• Technology

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Ecological Footprints by World Region

• The average American places at least 20 times the
  demand on Earths resources as does an average
  person in Bangladesh

Fig. 5.7 here
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Global Conditions for a Sustainable Population

• Lower fertility rates (stabilize population)
• Consumption must decrease
• Protect the environment (stewardly action must
  increase)

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Consequences of Population Growth and Affluence

• The developing countries
• Affluence

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Developing or Developed Nations?

• High fertility rates
• High consumptive lifestyles use 80 of worlds
  wealth
• Intense poverty
• Eat high on the food chain

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Developing or Developed Nations?

• Long doubling times
• High environmental degradation
• Twenty percent of the worlds population

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Basic Human Needs

• Drinkable Water
• Edible Food
• Safe Housing
• Health Care
• An Education
• A Job

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The Developing Countries

• Reform the system of land ownership
• Intensify cultivation of existing land to
  increase production per unit area
• Open new land to farm
• Move to cities and seek employment
• Engage in illicit activities for income
• Move to other countries

How do these solutions aggravate the problems?
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Growing Cities
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Consequences of Exploding Populations in the
Developing World
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Consequences of Exploding Populations
deforestation resource depletion loss of
agricultural land biodiversity disease pest
resistance population migration irrigation wetland
s
MORE
More Population Causes
LESS
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Affluence in the United States

• Consume the largest share of 11 of 20 major
  commodities
• Eat more than three times the global average in
  meat
• Lead the world in paper consumption
• Environment improves with increasing affluence

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Affluence in the United States

• Enables wealthy to clean up immediate environment
  by transferring waste to more distant locations.
• Affluent isolate themselves and unaware of the
  environmental stresses caused by their
  consumptive lifestyles.

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Dynamics of Population Growth

• Population profiles
• Future populations
• Population momentum
• The demographic transition

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Population Profiles of the United States
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Population Profile for United States
Note increasing elderly population.
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Future World Populations
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Future United States Populations
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Projecting Future Populations Developed Countries
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Population Projections Developing Nations
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Comparing Projected Populations (see Fig. 5-17)
Fertility Rate lt 2
Fertility Rate gt 2
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Population Momentum

• Countries like Iraq will continue to grow for
  5060 years even after the total fertility rate
  is reduced to replacement level.

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The Demographic Transition
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Calculating Fertility Rates and Doubling Times
(CBR CDR)/10 Rate of increase or decrease in
population per 1,000 per year
70/Rate of Increase Doubling Time
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Calculating Fertility Rates and Doubling Times
Practice (see Table 5-5)
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Demographic Transition Comparisons
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By the Year 2000

• 65 out of 117 countries will not be able to feed
  their own people
• One billion people will be living in cities that
  cannot support its inhabitants
• 400 million more women will be in need of child
  spacing services

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By the Year 2000 (continued)

• 600 million new jobs will need to be created for
  new entrants into the workforce
• We will need twice as much fresh water
• 300 million additional children will need
  teachers, books, and classrooms

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End of Chapter 5