1. AP Environmental Science
Human Population: Growth, Demography and Carrying Capacity
World Population Clock
© Brooks/Cole Publishing Company / ITP

2. Outline 1. Factors Affecting Human Population Size
birth and death rates
2. Population Age Structure
age structure diagrams, developing vs. developed countries
3. Solutions: Stabilizing Human Population
computer models, demographic transition
4. Case Studies
United States, India, China
5. Human Population and Sustainability
© Brooks/Cole Publishing Company / ITP

3. 1. Factors Affecting Human Population Size
Human population is currently growing exponentially.
What will be the ultimate size of the human population?
What is Earth's carrying capacity?
Population Crash Video Clip
Fig.1–1
© Brooks/Cole Publishing Company / ITP

4. Factors Affecting Human Population Size
Population change is calculated as the difference between individuals entering and leaving a population:
Population Change
Births + Immigration
Deaths + Emigration – =
birth rate is reported as the number of births per year/population
death rate is reported as the number of deaths per year/population
zero population growth (ZPG) occurs when factors that increase and decrease population size balance.
NOTE: when considering world population growth rates, immigration and emigration play no part (YET!)
© Brooks/Cole Publishing Company / ITP

5. Demography
Demography: the study of changes in size, composition and distribution of human populations.
Demographers study these trends, as well as their causes and consequences.

6. Crude Birth and Death Rates
Crude birth rate: number of births per year/1000 people. Crude death rates calculated in the same way. See Fig 10-3
Developing countries typically have higher crude birth and death rates—Africa #1
Birth rates in developed countries: 0.1%
Birth rates in developing countries: 1.5%
Birth rates and death rates decreasing worldwide
Death rates decreasing faster than birth rates, especially in developing countries ***Earth’s population increase is greatly due to decreased death rates.

7. World 21 9 All developed countries 11 10 All developing countries 24 8
Average crude birth rate
Average crude death rate
World 21 9
All developed
countries 11 10
All developing
countries 24 8
Developing
countries
(w/o China) 27 9
© 2004 Brooks/Cole – Thomson Learning

8. © 2004 Brooks/Cole – Thomson Learning
Africa 38 14
Latin
America 22
© 2004 Brooks/Cole – Thomson Learning 6
Asia 20 7
Oceania 18 7
United
States 14 8
North
America 14 8
Europe 10 12

9. Population Change Population growth: Pop = Pop0 + (b + i) - (d + e)
The annual rate of population increase is generally expressed as a percentage. Note the distribution of growth rates in 1998.
To figure the rate: (Pop - Pop0) / Pop0 X 100
OR use the rule of 70!
© Brooks/Cole Publishing Company / ITP

10. Population Change
***Between 1963 and 2004 the world’s annual population growth dropped 41% from 2.2% to 1.25%.
In this same time, the world population doubled to 6.4 billion.
A small, exponential population growth rate can still have large effects, especially if the population base is large.
The world is currently adding another New York City every month.

11. The Most Populous Countries
The world’s top five most populated countries :
#1 China1.3 billion
#2 India1.1 billion
These two countries together make up 37%
of the world’s total population
#3 United States
#4 Indonesia
#5 Brazil
See Figure 10-4
© Brooks/Cole Publishing Company / ITP

12. © 2004 Brooks/Cole – Thomson Learning
China
© 2004 Brooks/Cole – Thomson Learning
1.3 billion
1.4 billion
India
1.1 billion
1.4 billion
USA
294 million
349 million
Indonesia
219 million
308 million
Brazil
179 million
211 million
Pakistan
159 million
229 million
Russia
144 million
137 million
Bangladesh
141 million
205 million
Japan
128 million
121 million
Nigeria
137 million
206 million
2004
2025

13. Population Size and Fertility
Fertility: the number of births that occur to an individual woman or in a population.
Two types of fertility rates that affect a country’s population size and growth rate:
1)Replacement-level fertility rate
2)Total fertility rate (TFR)
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14. Replacement-Level Fertility vs. Total Fertility Rate
Replacement-level fertility: the number of kids a couple must have to replace themselves.
2.1 developed, 2.5 developing due to fact that some females die before reproducing
Reaching replacement levels does not mean immediate halt in population growth b/c many future parents are still alive.

15. Replacement-Level Fertility vs. TFR
Total fertility rate: the average number of kids a woman typically has during her reproductive years.
These have dropped sharply since 1950’s
Developed: 2.51.5
Developing 6.53.1 ** Highest currently in Africa
In the U.S. the time of the highest TFR was in the 1950’s after WWII. This was called the “Baby Boom.”

16. © 2004 Brooks/Cole – Thomson Learning
World
5 children per woman
2.8
Developed
countries
2.5
1.6
© 2004 Brooks/Cole – Thomson Learning
Developing
countries
6.5
3.1
Africa
6.6
5.1
Latin
America
5.9
2.6
Asia
5.9
2.6
Oceania
3.8
2.1
North
America
3.5
2.0
Europe
2.6
1.4
1950
2004

17. Total Fertility Rate
The expected population in future years depends on the world’s projected averageTFR (high:2.5, medium:2.0, low:1.5)
97% of the growth in all three estimates is projected to take place in developing countries.
See Fig 10-5 and 10-6

18. Population (billions)12 11
High
High
10.6 10
Medium
Low 9
Medium
8.9 8
Population (billions) 7 6
Low
7.2 5 4 3 2
1950
1960
1970
1980
1990
2000
2010
2020
2030
2040
2050
Year

19. Total Fertility in the United States
Total fertility in the United States had a major increase during the "baby boom" (1946–64) and is now hovering just below replacement level.
Fig.11–9
© Brooks/Cole Publishing Company / ITP

20. Factors Affecting Fertility Rates
The following are significant factors that decrease human fertility levels:
increase in average level of education and affluence
decrease in importance of child labor
increased urbanization—access to family planning
increased cost of raising and educating children
increased educational and employment opportunities for women
decreased infant mortality
higher average age of marriage
greater availability of private and public pensions
greater availability of reliable birth control
greater availability of legal abortions
change in religious beliefs, traditions, and cultural norms away from encouraging large families.
© Brooks/Cole Publishing Company / ITP

21. Birth Control
Typical effectiveness of birth control methods in the United States
The US is the #1 industrialized country for teen pregnancy rate
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22. Birth Control
Typical effectiveness of birth control methods in the United States (continued):
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23. Death Rates
Infant death rates are lower in developed countries than developing countries.
Fig.11–12
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24. Death Rates
Infant mortality: the number of babies of every 1,000 born who die before their first birthday.
At least 8 million infants (most in developing) die of preventable causes during their first year of life22,000 per day = 55 jumbo jet crashes with no survivors.
**Life expectancy and infant mortality rates (deaths/1000 before first birthday) determine health of people in a country.

25. Birth and Death Rates Over Time
The rapid growth in the world's population has not resulted from an ↑ in birth rates, but a ↓ in death rates.
Death rates have ↓ markedly during past 100 years
Birth rates have also ↓, but not as fast as death rates
The increasing difference between birth and death rates is what has lead to exponential population growth
The patterns of change in birth and death rates over time are different for developed vs. developing countries.
© Brooks/Cole Publishing Company / ITP

26. Birth and Death Rates Over Time
In developed countries decreases in death rates are being accompanied by decreases in birth rates over time.
Fig.11–11a
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27. Birth and Death Rates Over Time
In developing countries decreases in death rates have not been accompanied by as large of decreases in birth rates over time, leading to major population increase.
Fig.11–11b
© Brooks/Cole Publishing Company / ITP

28. 2. Population Age Structure
Age structure refers to the proportion of the population in each age class:
prereproductive (0–14 years)
reproductive (15–44 years)
postreproductive (45 and up)
© Brooks/Cole Publishing Company / ITP

29. Population Age Structure
Age structure of a rapidly growing vs. a slower growing population.
Rapidly growing populations have pyramid–shaped age structures, with large numbers of prereproductive individuals. Slower growing populations have a more even age distribution.
Fig.11–13a
© Brooks/Cole Publishing Company / ITP

30. Population Age Structure
Age structure of populations with zero growth vs. negative growth.
Populations with zero population growth have nearly equal proportions of prereproductive and reproductive individuals; whereas populations with negative growth have a greater proportion of reproductive than prereproductive individuals.
Fig.11–13b
© Brooks/Cole Publishing Company / ITP

31. Population Age Structure
Developing countries are expected to continue to have a pyramid shape through the year 2025, although the age structure will become somewhat more evenly distributed.
Fig.11–14a
© Brooks/Cole Publishing Company / ITP

32. Population Age Structure
Populations of developed countries are expected to have an increasingly even age distribution through the year 2025.
Age Structure Video Clip from hippocampus.org
Fig.11–14b
© Brooks/Cole Publishing Company / ITP

33. Population (2004) Population projected (2025) Infant mortality rate
United States (highly developed)
294 million
179 million
Brazil (moderately developed)
137 million
Nigeria (less developed)
Population
projected
(2025)
349 million
211 million
206 million
Infant
mortality
rate
6.7 33
100
Life
expectancy
77 years
71 years
52 years
Fertility
rate (TFR)
2.0
2.2
5.7
%Population
under
age 15
21%
30%
44%
% Population
over
age 65
12% 6% 3%
Per capita
GDP
$36,110
$7,450
$800
© 2004 Brooks/Cole – Thomson Learning

34. Population Age Structure
Population age structure of the United States continues to show a bulge as the baby boom generation ages. This has been compared to watching a boa constrictor swallow a pig.
Fig.11–15
© Brooks/Cole Publishing Company / ITP

35. 3. Solutions: Stabilizing Human Population
In 1972 the projections of a model, published in The Limits to Growth, indicated that if current economic, resource use, and population trends continue then we can expect economic and ecological collapse in the next century.
the results of this admittedly crude model challenged basic assumptions of industrial societies that there are no limits to industrial and population growth
twenty years later the authors updated their work in Beyond the Limits: Confronting Global Collapse, Envisioning a Sustainable Future (Donella Meadows et al. 1992)
despite limitations, computer models are an effective means for exploring possible future scenarios.
© Brooks/Cole Publishing Company / ITP

36. Computer Models of Human Population
This computer model projects what might happen if the world's population and economy continue to grow exponentially at 1990 levels.
Fig.11–18
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37. Computer Models of Human Population
This computer model projects how we can avoid overshoot and collapse to make a fairly smooth transition to a sustainable future by stabilizing fertility at two children per couple.
Fig.11–19
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38. Demographic Transition
A generalized model of the four stages of demographic transition.
**Explains how death rates fall before birth rates when a country becomes industrialized.
Fig.11–20
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39. Demographic Transition
1) Preindustrial Stage: both birth and death rates are relatively high (harsh living conditions) and approximately equal, such that the population does not increase, and the population size is small.
Fig.11–20
© Brooks/Cole Publishing Company / ITP

40. Demographic Transition
2) Transitional Stage: The population grows rapidly b/c death rate decreases markedly due to industrialization, increased food production, and improved health care.
Birth rates remain relatively high, so the population grows rapidly.
Fig.11–20
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41. Demographic Transition
3) Industrial Stage: Birth rate drops and eventually approaches a balance with death rate, leading to a slowing of population growth.
Fig.11–20
© Brooks/Cole Publishing Company / ITP

42. Demographic Transition
4) Postindustrial Stage: Birth rate and death rates approximately balance, zero population growth (ZPG) is attained, and the population stabilizes at a size much higher than the preindustrial size.
If birth rate declines below death rate negative population growth may even be attained.
Fig.11–20
© Brooks/Cole Publishing Company / ITP

43. Demographic Transition
Most developing countries are in the transitional stage because death rates have fallen more than birth rates
Reasons some analysts believe some of the conditions needed for the developing countries to develop are no longer available to some developing countries
Skilled workers to compete in today’s economy
Lack of capital and resources for economic development
Sharp rise in debt to other countries, leaving little for improvement
Less economic assistance since 1980’s
Demographic transition at hippocampus.org

44. 4. Case Studies Immigration in the United States: Fig.11–17
As fertility decreases, immigration has become a major source of population increase in the U.S.
In 1998 the U.S. received about 935,000 legal immigrants and 400,000 illegal immigrants--40% of our annual population growth!
Working immigrants boost the economy in the long run
Increasing levels of legal and illegal are expected.
Fig.11–17
© Brooks/Cole Publishing Company / ITP

45. Case Studies Population Control in India: Fig.11–16
In 1952 India began the first national family planning program
The program has been disappointing in India because of poor planning, inefficiency, low status of women, extreme poverty, and lack of funds
Couples still have an average of 3.5 children because of the belief that they need children to work and care for them in old age.
Fig.11–16
© Brooks/Cole Publishing Company / ITP

46. Family Planning Worldwide
Provide info about prenatal care
Help parents space births
Help parents regulate family size
Globally family planning:
Raised the use of modern contraception by married women in developing countries from 10% in 1960’s to 50% in 2004
Responsible for at least 55% of the drop in TFR’s for developing countries from 6 in 1960 to 3.1 in 2004

47. Case Studies Population Control in China: Fig.11–16
Since 1970, China, with the world's largest population, has initiated efforts to better feed its people and control population growth
Family planning successful
Strict population control measures prevent couples from having more than one child ** See book
Although considered coercive, the policy is significantly slowing population growth.
**See Fig 10-22
Fig.11–16
© Brooks/Cole Publishing Company / ITP

48. India China Percentage of world 17% population 20% Population
1.1 billion
1.3 billion
Population (2025)
(estimated)
1.4 billion
1.4 billion
Illiteracy (%of adults)
47%
17%
Population under age 15(%)
36%
22%
Population growth rate (%)
1.7%
0.6%
Total fertility rate
3.1 children per woman (down from 5.3 in 1970)
1.7 children per woman (down from 5.7 in 1972)
Infant mortality rate 64 32
Life expectancy
62 years
71 years
GDP PPP per capita
$2,650
$4,520

49. 5. Human Population and Sustainability
How can governments reduce population growth?
improve access to family planning and reproductive health care
improve heath care for infants, children, and pregnant women
encourage development of national population policies
improve equality between men and women
increase access to education, especially for girls
increase the involvement of men in child rearing and family planning
reduce poverty
reduce and eliminate unsustainable patterns of production and consumption.
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50. Women Empowerment and Sustainability
Three factors that lead to women having fewer, healthier children
Education, job outside home, rights
Women do 60-80% of the work associated with growing food, gathering fuel and hauling water in rural areas
Globally women account for 2/3 of all hours worked but receive only 10% of the world’s income and 2% of the world’s land.
Achieving equality would slow population growth, promote freedom, reduce poverty and slow environmental degradation.