IB Geography Topic 1.2.1 Demographic Transition and…

Population Growth Facts

For most of human history population growth was negligible due to high mortality (especially among children) despite high fertility rates.
Rapid population growth dates back to the late 18th and 19th Centuries due to introduction of basic healthcare and improved living conditions in future HICs.

The world population has reached 8 billion and is expected to stabilize by the end of 21st Century at between 10 to 12 billion. By 2100-2150 it could be down to 9 billion.
In 2023 India has overtaken China as the most populated country in the world
About 10% of world’s population is over 65 - by 2100 this proportion will have risen to one-third
The average total fertility rate dropped significantly from 5.06 in 1964 to 3.28 in 1990 and then further to 2.3 currently.

Now Over 50% of the world's population can be found in Asia, but its share in global population will decline whereas Africa's will increase.
Population growth in Asia will be over by the mid-21st Century, whereas Africa is the only region projected to experience further population growth throughout the 21st Century.

Trends in Fertility, Mortality, and Dependency

Natural Increase: The Balance Between Births and Deaths

Definition

Natural increase

Natural increase is the difference between the crude birth rate (CBR) and the crude death rate (CDR), expressed as a percentage.

Calculating Natural Increase

Crude Birth Rate (CBR): Number of live births per 1,000 people per year.
Crude Death Rate (CDR): Number of deaths per 1,000 people per year.

$$\text{Natural Increase (%) = CBR - CDR}$$

Fertility Rate: The Drivers of Population Growth

Definition

Total Fertility Rate (TFR)

The total fertility rate (TFR) is the average number of children a woman is expected to have during her reproductive years (ages 15–49), also called childbearing age.

The TFR of 2.1 is called a replacement rate - rate that allows to maintain the same population size over time.

Influencing Factors

Status of Women: Higher education and employment opportunities often lead to lower fertility rates.
Economic Conditions: In LICs, children may be seen as economic assets, increasing fertility rates.
Cultural and Religious Norms: Some societies encourage larger families.
Access to Healthcare: Availability of contraception and maternal health services can reduce fertility rates.

Example

Japan has high female employment rates but low fertility (1.2) due to the high cost of childcare and cultural work-life balance challenges.

Example

Nigeria's fertility rate remains high (5.2 children per woman) due to reliance on agriculture and limited access to contraception.

Dependency Ratio: Balancing the Working and Non-Working Populations

Definition

Dependency ratio

The dependency ratio measures the proportion of dependents (people aged below 15 and above 65) to the working-age (economically active) population (15–64).

Older dependency ratio measures the proportion of old dependents (people aged above 65) to the working-age (economically active) population (15–64).

Calculating Dependency Ratio

$$\text{Dependency Ratio} = \frac{\text{Number of Dependents}}{\text{Working-Age Population}} \times 100%$$

Common Mistake

Don't confuse the dependency ratio with the proportion of elderly people.
Remember, the dependency ratio includes both the young and the elderly.

Note

While the dependency ratio is a useful indicator, it is a crude measure.
Many people work beyond age 64 or remain in education past age 15.

Key Demographic Metrics

Definition

Infant Mortality Rate (IMR)

Number of deaths of children under 1 year per 1,000 live births.

Definition

Child Mortality Rate (CMR)

Number of deaths of children under 5 years per 1,000 live births.

Definition

Life Expectancy

Average number of years a person is expected to live based on current mortality rates.

Life expectancy varies widely across the world.

Population Growth Facts

For most of human history population growth was negligible due to high mortality (especially among children) despite high fertility rates.
Rapid population growth dates back to the late 18th and 19th Centuries due to introduction of basic healthcare and improved living conditions in future HICs.

The world population has reached 8 billion and is expected to stabilize by the end of 21st Century at between 10 to 12 billion. By 2100-2150 it could be down to 9 billion.
In 2023 India has overtaken China as the most populated country in the world
About 10% of world’s population is over 65 - by 2100 this proportion will have risen to one-third
The average total fertility rate dropped significantly from 5.06 in 1964 to 3.28 in 1990 and then further to 2.3 currently.

Now Over 50% of the world's population can be found in Asia, but its share in global population will decline whereas Africa's will increase.
Population growth in Asia will be over by the mid-21st Century, whereas Africa is the only region projected to experience further population growth throughout the 21st Century.

Trends in Fertility, Mortality, and Dependency