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

2
Human Population Growth and the Consequences

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

3
Human Population Expansion and Its Cause

• Reasons for the patterns of growth
• Biotic potential exceeds environmental
  resistance birth rates exceed death rates
• There are 7 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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Stage 1 Preindustrial
Stage 2 Transitional
Stage 3 Industrial
Stage 4 Postindustrial
High
Birth rate
Relative population size
Birth rate and death rate (number per 1,00 per
year)
Death rate
Total population
Low
Low
Increasing
Zero
Negative
Low
Very high
Decreasing
Growth rate over time
Fig. 9-14, p. 183
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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