1. Chapter 9: The Human Population

2. Demography
Definition: the study of populations, most often human populations
Includes study of:
History of the population
Current makeup of population
Properties that affect the population, such as economics and social structure
Make predictions

3. The Human Population Over Time
Yr. each billion was reached
2015*
1999
1987
1974
1960
1930
1880
* projected

4. And the Current World Population Is…
Population clock

5. Population Size
Population size = (births + immigration) – (deaths + emigration)
Crude birth rate (CBR) = number of live births per 1000 people in a population per year
Crude death rate (CDR) = number of deaths per 1000 people in a population per year
Annual rate of natural population change (%) = birth rate – death rate divided by 1000 persons multiplied by 100

6. Falling growth rates do not mean fewer people
Falling rates of growth do not mean a decreasing population, but only that rates of increase are slowing

7. World Population Statistics

8. 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

9. © 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

10. © 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
Population sizes of most populous countries in 2004 and projected population size for 2025
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

11. Forecasting Population Size
Population size = (births + immigration) – (deaths + emigration)
Based on current data
Based on general population properties
Not always accurate!

12. Properties of Populations used in forecasting
1. Age Structure – definition: the distribution of ages in a specific population at a certain time
Graphed as a population pyramid, defined as a double-sided bar graph showing percent of males and females in different age groups

13. Generalized Population Pyramid
Three stages of life
0-14 years: Prereproductive
15-44 years: Reproductive
45+ years: Postreproductive
The percent of the population in each stage indicates what the population will probably do in the future…

14. Why will Kenya experience rapid growth
Why will Kenya experience rapid growth? Why is there a bulge in the middle age range for the U.S.? Do males or females generally live longer?

15. Properties of Populations used in forecasting
2. Total fertility rate (TFR) – definition: the average number of children born per woman in her lifetime
High rates mean greater population growth
Replacement level – number of children needed per couple to replace them and maintain a stable population (in U.S., it is 2.1 because not all children survive and have children themselves)

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
Fertility rates for women in different countries in 1950 and 2004
Oceania
3.8
2.1
North
America
3.5
2.0
Europe
2.6
1.4
1950
2004

17. When was the “baby boom”?
When was the “baby bust”?
If replacement rate is 2.1, when did the fertility rate first drop below that level?

18. Fertility rates remained below replacement level for most of the 1990s, but recently has been growing partly because the children of the baby boom grew up and had children.

19. Properties of Populations used in forecasting
3. Migration patterns – immigration and emigration can influence overall population size
Most countries do not encourage immigration – exceptions are Canada, Australia and the U.S.
“Since 1820 the United States has admitted almost twice as many immigrants as all other countries combined.”

20. 4. Life Expectancy
Definition: average number of years a person is likely to live
Most influenced by infant mortality (death before one year old)

21. Humans by Era Average Lifespan at Birth (years)
Neanderthal 20
Upper Paleolithic 33
Neolithic 20 
Bronze Age 18 
Classical Greece 20-30
Classical Rome 20-30 
Pre-Colombian North America 25-35 
Medieval Britain 20-30 
Early 20th Century 30-40 
Current world average 67

22. Life Expectancy Around the World
What conclusions can you draw?

23. Name a country…
World Life Expectancy Chart

24. 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
GNI PPP
$36,110
$7,450
$800
© 2004 Brooks/Cole – Thomson Learning

25. Is this where we are headed?
Maybe, maybe not…

26. Demographic Transition Model (DTM)
Definition: a model that describes how societies change from high birth and death rates, to low birth and death rates as they move toward industrialization
Theory behind the model: industrialization causes social and economic development that influences population growth rates

27. Relative population size Birth rate and death rate
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
Low
High
Relative population size
(number per 1,000 per year)
Birth rate and death rate 80 70 60 50 40 30 20 10
Birth rate
Death rate
Total population
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time
Stage 1: Pre-industrial stage
High birth rate (many children needed to help family survive), high death rate (virtually no medical care, poor diet, much disease), population grows slowly or not at all

28. Relative population size Birth rate and death rate
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
Low
High
Relative population size
(number per 1,000 per year)
Birth rate and death rate 80 70 60 50 40 30 20 10
Birth rate
Death rate
Total population
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time
Stage 2: Transitional stage
Death rate begins to fall as medical care and sanitation improve, population size increases because birth rate remains high

29. Relative population size Birth rate and death rate
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
Low
High
Relative population size
(number per 1,000 per year)
Birth rate and death rate 80 70 60 50 40 30 20 10
Birth rate
Death rate
Total population
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time
Stage 3: Industrial stage
Birth rate declines as fewer children as needed for family survival, improvements in women’s education and access to birth control result in later and fewer pregnancies, death rate continues to fall as medical care, sanitation and diet improve, overall population continues to rise but more slowly

30. Relative population size Birth rate and death rate
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
Low
High
Relative population size
(number per 1,000 per year)
Birth rate and death rate 80 70 60 50 40 30 20 10
Birth rate
Death rate
Total population
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time
Stage 4: Post-industrial stage
Population growth stabilizes, birth and death rates are low, good health care and family planning, improving status of women

31. Another summary of the Demographic Transition Model

32. Analysis of DTM

33. Is the demographic transition universal?
It has occurred in Europe, U.S., Canada, Japan, and other nations over the past years
But, it may or may not apply to all developing nations
The transition could fail in cultures
That place greater value on childbirth or
Grant women fewer freedoms
For people to attain the material standard of living of North Americans, we would need the natural resources of four and a half more Earths

34. Changing Population Trends
Throughout history, and currently in many parts of the world, populations that have high rates of growth create environmental problems.

35. Impact of Human Population on the Environment
I=PAT
I = impact on environment
P = population size
A = affluence (consumption)
T = technology (environmental impact per unit of consumption)
“Formula” developed in 1970s by Paul Ehrlich, Barry Commoner and John Holdren

36. Problems of Rapid Growth
Increased depletion of natural resources -
such as fuel to cook, boil water, use for transportation
fertile soil
water
Africa’s Sahel region and western China are turning to desert

38. Problems of Rapid Growth
Increased pollution –
water: with too many people, local water supply may be used for drinking, washing and sewage disposal, leading to spread of infectious disease
air pollution – China’s large population and economic growth has resulted in severe air pollution due to the use of coal as the primary energy source
2008 Olympic games in Beijing

39. Problems of Rapid Growth
3. Increased land use
Growing populations may have a shortage of arable (farmable) land
Urbanization – increase in the ratio of people living in cities vs rural areas
Suburban sprawl – problems: traffic, inadequate infrastructure, land used for housing instead of farms or wildlife
Desertification and erosion due to agriculture
Urbanization closing in on a river

40. Wealth also produces severe environmental impacts
The population problem does not exist only within poor countries
Affluent societies have enormous resource consumption and waste production
People use resources from other areas, as well as from their own
Individuals’ ecological footprints are huge
One American has as much environmental impact as 6 Chinese or 12 Indians or Ethiopians

41. The wealth gap and population growth cause conflict
The stark contrast between affluent and poor societies causes social and environmental stress
The richest 20% use 86% of the world’s resources
Leaves 14% of the resources for 80% of the world’s people to share
Tensions between “haves” and “have-not’s” are increasing

42. Managing Development and Population Growth
Today, less developed countries face the likelihood that continued population growth will prevent them from imitating the development of the world’s economic leaders.
Countries such as China, Thailand, and India have created campaigns to reduce the fertility rates of their citizens through public advertising, family planning programs, economic incentives, or legal punishment.
Successful programs:
China (reduced TFR from 5.7 to 1.7 in 30 years)
Thailand (reduced growth rate from 3% to 1.1% in 30 years)

43. Managing Development and Population Growth
In 1994, the United Nations held the International Conference on Population and Development (ICPD),
It involved debates about the relationships between population, development, and the environment.
Many countries favor stabilizing population growth through investments in development, especially through improvements in women’s status.

45. Work day for a woman in developing country
4:45 A.M.
Wake,
wash, and
eat
5:00 A.M.-
5:30 A.M.
Walk to
fields
5:30 A.M.-
3:00 P.M.
Work in
fields
3:00 P.M.-
4:00 P.M.
Collect
firewood
4:00 P.M.-
5:30 P.M.
Pound and
grind corn
5:30 P.M.-
6:30 P.M.
Collect
water
6:30 P.M.-
8:30 P.M.
Cook for
family and
eat
8:30 P.M.-
9:30 P.M.
Wash
dishes
and children
9:30 P.M.
Go to bed

46. Empowering women reduces growth rates
Fertility rates drop when women gain access to contraceptives, family planning programs and better educational opportunities
In 2007, 54% of married women worldwide used contraception;
China = 86%; the U.S. = 68%; 20 African nations < 10%
Women with little power have unintended pregnancies

47. With these goals, worldwide fertility rates are dropping as shown below.

48. Looking at the graph below, most demographers predict the medium growth rate, and a world population of 9 billion in 2050.

49. Conclusion: Withgott and Brennan
The human population is larger than at any time in the past
Populations are still rising, even with decreasing growth rates
Most developed nations have passed through the demographic transition
Expanding rights for women slows population growth
Will the population stop rising through the demographic transition, restrictive governmental intervention, or disease and social conflict caused by overcrowding and competition?
Sustainability requires a stabilized population in time to avoid destroying natural systems