1. Where has the world’s population increased?
Key Issue 2
Where has the world’s population increased?

2. Population Change
Geographers measure population change in a country or the world as a whole through three measures:
Crude Birth Rate
Crude Death Rate
Natural Increase Rate (NIR or NRI)
WHY ARE THESE IMPORTANT?
What do they tell us about the world?
Increase in population
Predict how quickly
Population trends

3. Crude Birth/Death Rate
Crude means the world as a whole
CBR Definition:
Total # of live births in a year for every 1,000 people
Example:
CBR of 20 =
20 births per 1,000 in a 1 year period
CDR Definition:
Total # of deaths in a year for every 1,000 people

4. Natural Increase NIR definition:
% by which a population grows each year
Formula:
CBR- CDR = NIR
20 – 5 = 15
=1.5% NIR
Natural increase means migration is excluded
World NIR
Early 21st century = 1.2%
All time peak in 1963 with 2.2%
80 million people added annually
Even though NIR is slowing, population base is large

5. Doubling Time Rate of NIR effects doubling time Definition:
# of years needed to double a population
Example
NIR of 1.2 = 54 years to double
If world NIR remains steady through 21st century world population will be 24 billion by 2100
More than 95% of NIR is clustered in LDCs
Exceeds 2.0 in sub-saharan Africa and Middle East

6. Population Explosion
The population continues to “explode” as the doubling time decreases.
Example:
8 A.D. – 250 million
1650 A.D million
1820 A.D.- 1 billion
1930 A.D.- 2 billion
1975 A.D.- 4 billion

7. Fertility Total Fertility Rate World TFR = 2.6
Measures the # of births in society
Average # of children a woman will have during childbearing years (15-49 years)
CBR provides picture of society for given year
TFR attempts to predict future behavior of individual women
World TFR = 2.6
Sub-saharan Africa =6
Western Europe= .09

8. Mortality IMR rates highest in poorer countries U.S. special example
Sub-Saharan Africa
100 means 10% of all babies
Often reflect’s countries healthcare system
U.S. special example
high MRI for a MDC
Why?
Minorities, poor population access to healthcare
Two useful measures
CDR
Infant mortality rate
Definition:
# of deaths of infants under 1 year of age per year

9. Death Rate
Death rate is not a good statistic to use in determining quality of life.
Why?
Not all countries are at same stage….
Example: US is wealthy MDC but may have more deaths because of an older population than Ethiopia.

10. Life Expectancy Definition:
Average # of years a newborn infant can expect to live at current mortality levels
Like all mortality/fertility rates higher in core/MDC nations
Western Europe = 80 years
Sub-Saharan Africa= 50 years
All become repetitious because all follow similar patterns

11. Population Growth Curves
S Curve – historical growth
J Curve – exponential growth (fixed percentage)