1. Key ? 2: Why Do Populations Rise or Fall in Particular Places?
Thomas Malthus
An Essay on the Principles of Population (1798)
Population growing exponentially
Food supplies growing linearly
What happened?
Expansion of food supply sources
(globalization)
Increase in agricultural
productivity (exponentially)

2. Food & Population, 1950-2000 Malthus vs. Actual Trends
Fig. 2-20: Malthus predicted population would grow faster than food production, but food production actually expanded faster than population in the 2nd half of the 20th century.

3. Crude death rate (CDR)-the number of deaths per 1,000 each year.
Crude birth rate (CBR)-the number of births per 1,000 each year.
Natural increase rate (NIR) -the % by which a population grows in a year. Computed by subtracting the % of CBR-CDR.
Total Fertility Rate (TFR) the number of children born to women of childbearing age-usually reported as a percentage.
Dependency ratio-the number of people who are too young or too old to work compared to the number of people old enough to work.
Crude Birth Rate is the total number of live births in a year per 1,000 people in a society. A crude birth rate of 20 means that for every 1,000 people in a country-20 babies are born over a one-year period.
Crude Death rate is the total number of deaths in a year for every 1,000 people.
Natural increase rate is the percentage by which a country grows each year. If the CBR is 20 and the CDR is 5 the NIR is 15 per 1000 or 1.5 this excludes migration or immigration.

4. Natural Increase Rate Highest in 1963 at 2.2%; has gotten lower since
Currently 80 million people are added annually
Small changes in NIR shows drastic increases or decrease in pop. growth

5. Population Growth From Dawn of History to 1820 to reach 1 billion
1970s only 12 years to add another billion.
Then a decade for another billion.
billion-world population increased from 3 to 4 billion in 14 years
billion-from 4 to 5 billion in 13 years
billion-from 5 to 6 billion in 12 years
A growth rate of 1 billion people per decade.
By 1997 growth rate was 1.5% - today 1.4%

6. World Population Growth 1950 - 2005
Fig. 2-6: Total world population increased from 2.5 to over 6 billion in slightly over 50 years. The natural increase rate peaked in the early 1960s and has declined since, but the number of people added each year did not peak until 1990.

7. Natural Increase Rates
Fig. 2-7: The natural increase rate (NIR) is the percentage growth or decline in the population of a country per year (not including net migration). Countries in Africa and Southwest Asia have the highest current rates, while Russia and some European countries have negative rates.

8. Doubling Time
Number of years for a population to double in size (like a bank deposit at compound interest)
Decreased doubling time (rapid growth), then increased doubling time (growth slowed down)
Doubling time = 54 years
Doubling time = 45 years

9. Fertility
Highest CBR in Sub-Saharan Africa (CBR=over 40); lowest in Europe (CBR=under 10)
TFR=Total Fertility rate= average # of kids a woman will have
This predicts future cultural patterns of women
TFR in world is 3; TFR in sub-Saharan Africa is 6; TFR in Europe is 2

10. Total Fertility Rate (TFR)
The average number of children per woman
TFR needed to maintain the population size: 2.1

11. Total Fertility Rate (TFR)
The average number of children per woman
TFR needed to maintain the population size: 2.1

12. Crude Birth Rates
Fig. 2-8: The crude birth rate (CBR) is the total number of births in a country per 1000 population per year. The lowest rates are in Europe, and the highest rates are in Africa and several Asian countries.

13. Mortality
IMR= infant mortality rate= annual # of infant deaths under 1 year of age, compared with annual live births
Highest IMR in poor countries; what does this show?
IMR decreases with good doctors, modern techn., & hospitals & lots of increase to medicine
US has a higher IMR than Europe & Canada due to economic differences in minority groups

14. Dramatic declines in the rates have occurred in all countries as a result of international health care delivery programs. Despite these efforts the most dramatic decreases in infant mortality have been in the urbanize, industrialized west.

15. Infant Mortality Rates
Fig. 2-10: The infant mortality rate is the number of infant deaths per 1000 live births per year. The highest infant mortality rates are found in some of the poorest countries of Africa and Asia.

16. Mortality cont.
Life expectancy= average # of years a newborn infant can expect to live at current mortality rates
This is higher in wealthier countries, MDCs
MDC’s=NIR ,CBR,TFR, IMR,life expectancy
LDC’s= NIR, CBR, TFR, IMR, life expectancy 

17. Life Expectancy at birth
Fig. 2-11: Life expectancy at birth is the average number of years a newborn infant can expect to live. The highest life expectancies are generally in the wealthiest countries, and the lowest in the poorest countries.

18. Population Growth in India
Significant demographic variations within countries: Higher growth rates in northeastern India,
lower rates in southeastern India

19. Population in India 1950s: Population planning program
1960s: National population planning program
1970s: Beginning of forced sterilization program for men with 3 or more children; 22.5 million men sterilized
2004: Beginning of guns-for-sterilization program in Uttar Pradesh
Today: Use of advertising and persuasion to lower birth rates in most states

20. The Demographic Transition
Changes in birth, death, and natural increase rates
Decline in death rates followed by decline in birth rates, resulting in a low or stable growth rate

21. Demographic cycles of population growth
Stage 1 High Stationary Growth (Low Growth) with high birth rates 40/1000 or higher and high death rates.
Stage 2 Early (High Growth) birth rates and declining death rates (birth 40s/death 20/1000) = rapid growth in pop.
Stage 3 Late Expanding (Moderate Growth) with declining birth rates (30s) and low death rates (10) = still significant growth
Stage 4 Low Stationary (Low Growth) has low birth and low death rates (birth 15 and death 10 or lower) SPL Stationary Population Level
Stage 1 has virtually no growth rate with very high birth and death rates. Most of human existence was in Stage 1 of the Demographic Transition model. Today no country is in this category.
Stage 2 has rapidly declining death rates and very high birth rates to produce population growth. In the late 18th and early 19th centuries several countries moved to stage 2 as the Industrial Revolution took place. Europe and North America entered Stage 2 about 1800, but Africa, Asia and South America did not reach stage 2 until around Africa, Asia and Latin America reached Stage 2 not because of an Industrial Revolution, but a medical revolution invented in Europe and North America and diffused to these places.
Stage 3 European and North American countries moved from Stage 2 to Stage 3 in the first half of the 20th cent. Most of Asia and Latin America moved to Stage 3 in the last half of the 20th cent. while Africa remained in Stage 2. Nations enter Stage 3 when people decide to have fewer kids since living in cities and working in factories or offices requires fewer people.
Stage 4 When the crude birth rate equals the crude death rate zero population growth is achieved or Stage 4.
Some argue that this model is useful only to study the demographic history of the core countries.

22. The Demographic Transition

23. Demographic Transition in England
Fig. 2-14: England was one of the first countries to experience rapid population growth in the mid-eighteenth century, when it entered stage 2 of the demographic transition.