1. Why Does Population Growth Vary Among Regions?
Chapter 2 Key Issue 3

2. Demographic Transition Model
Explaining Spatial Patterns
of World Population Growth
Many graphics in this powerpoint are from Michael Kuby et al., Human Geography in Action (instructor package) or online materials posted by Keith Montgomery, Dept of Geology and Geography, Univ of Wisconsin - Marathon County (

3. The Demographic Transition
Process of Change in society’s population from high CBR, CDR, and low NIR to a condition of low CBR, CDR, and NIR

4. Demographic Transition Model
DISCUSSION:
* Are there countries that do not fit this model?

5. DTM only predicts changes in birth/death rates over time
Observed changes in NIR correlate to changes in economic development
Thus, DTM implies:
The greater the wealth,
the lower the NIR... but use caution describing this relationship

6. Stages in Classic 4-Stage Demographic Transition Model (DTM)
(Some books show a 3-stage model; others mention a new 5th stage)

7. Stage 1: “Pre-Industrial”
High birth rates and high death rates (both about 40)
Population growth very slow
Agrarian society
High rates of communicable diseases
Pop. increases in good growing years;
declines in bad years (famine, diseases)
No country or world region still in Stage One

8. Stage 2: “Early Industrial”
High birth rates (over 30) but death rates decline (to about 20)
RNIs increase sharply (pop. explosion); growth rate increases thruout Stage Two
Growth not from increase in births, but from decline in deaths
MDCs = starts early 1800s
LDCs = starts after 1950s

9. TRANSITION TO STAGE TWO IN CLASSIC DTM
Known as the Epidemiologic Transition
Agricultural technology
Improvements in food supply: higher yields as agricultural practices
improved in “Second Agricultural Revolution” (18th century)
In Europe, food quality improved as new foods introduced from Americas
Medical technology
Better medical understanding (causes of diseases; how they spread)
Public sanitation technologies
Improved water supply (safe drinking water)
Better sewage treatment, food handling, and general personal hygiene
Improvements in public health especially reduced childhood mortality

10. Declining Infant Mortality Rates

11. When IMR declines, fertility rates drop soon after

12. Stage 3: “Later Industrial”
Birth rates decline sharply (to about 15)
Death rates decline a bit more (to about 10 or less)
Note growth still occurs, but at a reduced and declining rate
MDCs = starts in late 1800s
LDCs = starts after 1980s*
* Or hasn’t started yet

13. Measles Mortality, US, since 1900
Stage Three:
Further improvements in medicine lower death rates more; raise life expectancies
Measles Mortality, US, since 1900
TB Mortality, US, since 1900

14. TRANSITION TO STAGE THREE IN CLASSIC DTM
Known as the Fertility Transition
Societies become more urban, less rural
Declining childhood death in rural areas (fewer kids needed)
Increasing urbanization changes traditional values about having children
City living raises cost of having dependents
Women more influential in childbearing decisions
Increasing female literacy changes value placed on motherhood
as sole measure of women’s status
Women enter work force: life extends beyond family, changes attitude
toward childbearing
Improved contraceptive technology, availability of birth control
But contraceptives not widely avail in 19th century; contributed little to
fertility decline in Europe … Fertility decline relates more to change in
values than to availability of any specific technology

15. Rapidly increasing urbanization in world LDCs today
Population Classified as Urban

16. Strong inverse relationship between female literacy and fertility rates, observed globally
Increasing availability and use of modern contraception in most LDCs since 1970s

17. Stage 4: “Post-Industrial”
Birth rates and death rates both low (about 10)
Population growth very low or zero
MDCs = starts after 1970s
LDCs = hasn’t started yet
Stage 5 (?): Hypothesized (not in Classic DTM)
Much of Europe now or soon in population decline
as birth rates drop far below replacement level

18. Key Population Indicators for Selected Countries
DISCUSSION:
* Are there any countries still in stage 1 of the demographic transition?
* What other countries not shown would you expect to find in stages 2, 3, and 4?

19. Differences in DTM experience: MDCs & LDCs
● Faster decline in death rates — Tech improvements diffused from MDCs & applied rapidly in LDCs post-WW2
● Longer lag between decline in deaths and decline in births — Stage 3 slower start in LDCs where econ growth is delayed
● Higher max rates of growth in LDCs — Over 3.5% peak RNI in Mauritius and Mexico; only 1.3% peak in Sweden

20. Age structures today in LDCs are much younger than MDCs experienced – leading to prolonged “Demographic Momentum” – expected growth of pop. long after fertility declines
Percentage of Population Under Age 15

21. The Demographic Transition
Fig. 2-13: The demographic transition consists of four stages, which move from high birth and death rates, to declines first in death rates then in birth rates, and finally to a stage of low birth and death rates. Population growth is most rapid in the second stage.

22. Population Pyramid of the U.S.

23. Population Pyramids in U.S. cities
Fig. Population pyramids can vary greatly with different fertility rates (Laredo vs. Honolulu), or among military bases (Unalaska), college towns (Lawrence), and retirement communities (Naples).

24. Rapid Growth in Cape Verde
Cape Verde, which entered stage 2 of the demographic transition in about 1950, is experiencing rapid population growth. Its population history reflects the impacts of famines and out-migration.

25. Moderate Growth in Chile
Chile entered stage 2 of the demographic transition in the 1930s, and it entered stage 3 in the 1960s.

26. Low Growth in Denmark
Denmark has been in stage 4 of the demographic transition since the 1970s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children.

27. Demographic Momentum (hidden momentum)
Critics
Based on England
Billions and much faster then ever before
Graying Population
Medical Revolution- 1900’s
Demographic Momentum (hidden momentum)

28. Summary of DTM for LDCs
Industrializing LDCs with some economic development follow DTM more closely; now in Stage Three. Most like MDCs in places where female literacy has increased the most.
Lowest-income countries have high birth rates and deaths are leveling off at higher rates than DTM predicts (Stage Two).
In some LDCs, death rates starting to increase (epidemics, worsening poverty)

29. Dependency Ratio
# of people too old (65 years & up) or too young (0-14 years) to work compared to the # of productive workers

30. Percent of Population Under Age 15
Fig. 2-12: The crude death rate (CDR) is the total number of deaths in a country per 1000 population per year. Because wealthy countries are in a late stage of the Demographic Transition, they often have a higher CDR than poorer countries.

32. Sex Ratio
# of males per 100 females in the population

34. The population pyramid displays the age
POPULATION STRUCTURE
The population pyramid displays the age
and sex structure of a country or given area
OLD DEPENDANTS
ECONOMICALLY
ACTIVE
YOUNG
DEPENDANTS
Population in
Five Year
Age bands
FEMALES
To the right
MALES
To the left
Usually, but not always,
in % to make for easier
comparisons
between countries

35. What Population Pyramids Show Us
KEY
The overall shape of the population pyramid can indicate whether it is an
Economically More Developed Country or Economically Less Developed Country
Economically
More
Developed
Country
Less
slope of pyramid indicate the death rate
height of graph can indicate life expectancy (ignore the very thin end of the wedge as occurs on graph B as these people are a definite minority)
proportions of men and women can suggest male or female migrations
"kinks" indicate dramatic reductions in birth rate or increases in death rate in the past
width of the base is related to birth rate/fertility rate
area of graph indicates total population - compare areas of different population age groups or different sex on one graph

36. Population Pyramids related to the Demographic Transition Model
Stage 1
Stage 2
Stage 3
Stage 4
IMPLICATIONS
Both birth rates and
Death rates are
High, so population
growth rates are
slow but population
Is usually restored
Due to high birth
Rate. Short life
Expectancy
EXAMPLES: none today - Afghanistan, Ivory Coast (30 years ago)There are no Stage 1 countries today
Population starts
to grow at an
exponential rate due to fall in Crude Death Rate. More living In middle age.
Life expectancy rises
Infant mortality rate falls.
EXAMPLES: DR Congo, Yemen, Afghanistan (today)
Population continues
to grow but at slower
rate. Low C Death Rate.
Dramatically declining
Crude Birth Rate.
EXAMPLES: India, Brazil (late 3) – Most of world is in 3
Low Crude Birth Rate
and Crude Death Rate
Higher dependency ratio
and longer life expectancy
Crude Death Rate does
Rise slightly because of
The ageing population
EXAMPLES: China, United States, Canada, Australia
There is some merit in including or considering
a Stage 5 today with a declining population-
Europe - Japan

37. Practice with real pyramids-What Stage of DTM?4 3 5 2

38. Practice with real pyramids-What Stage of DTM is US? Challenging – why?
2011 Data
TFR 2.1
BR 14
DR 8
Natural Increase: .6%
Growth Rate: .9%
Why is Growth Rate higher?
How does this impact pyramid?
Pyramid looks like a late 3 country.
But does US fit description profile of Stage 4 better?