Introduction
Understanding the changing population is crucial in Geography, especially within the International Baccalaureate (IB) syllabus. This study note will cover various aspects of population change, including demographic transition, ageing populations, migration, and their impacts on society. We will break down complex ideas into smaller sections, providing clear explanations and real-world examples to enhance comprehension.
Demographic Transition Model (DTM)
The Demographic Transition Model (DTM) illustrates the transition of a population from high birth and death rates to lower rates over time. It is divided into five stages:
Stage 1: High Stationary
- Birth Rate (BR): High (~35/1000)
- Death Rate (DR): High (~35/1000)
- Population Change: Stable
Explanation:
- Lack of birth control, poor education around family planning.
- High infant mortality rates lead to more children being born to replace those who die.
- Children are needed to help work on the land.
Stage 2: Early Expanding
- BR: High (~35/1000)
- DR: Falls quickly (~15/1000)
- Population Change: Very fast natural increase
Explanation:
- Improved sanitation, medical care, and food and water supply.
- Mortality rates, especially infant mortality, decrease significantly.
Stage 3: Late Expanding
- BR: Falls quickly (~15/1000)
- DR: Still falling but slower (~10/1000)
- Population Change: Increase slows
Explanation:
- Further availability of contraception.
- Career advancement for women.
- Children turn from economic assets to burdens.
Stage 4: Low Stationary
- BR: Falls further and remains low (~10/1000)
- DR: Low (~10/1000)
- Population Change: Very slow increase
Explanation:
- More elderly population, so a smaller proportion of women of reproductive age.
Stage 5: Decline
- BR: Falls very low and below DR
- DR: Climbs slightly higher than BR
- Population Change: Natural decrease
Explanation:
- Ageing population with a higher proportion of elderly individuals.
Note:
The DTM is based on the historical population trends of England, Wales, and Sweden, and may not perfectly apply to all countries.
Ageing Population
Overview
Also known as a greying population, the ageing demographic is characterized by an increasing number of older persons in the population.
- In 2020, the number of people aged 60+ years outnumbered children younger than 5 years.
- In 2022, almost 10% of the world’s population (771 million people) were aged 65+ years.
- Between 2015 and 2050, the world's population over 60 years will nearly double from 12% to 22%.
- By 2050, two-thirds of the world’s population over 60 years will live in low- and middle-income countries.
Examples
- Japan: 30% of the population is elderly.
- Italy: 24% of the population is elderly.
- Finland: 23% of the population is elderly.
- Qatar, Uganda, Afghanistan: Only 2% of the population is aged 65+ years.
Reasons for Ageing Population
- Decreased mortality and fertility rates globally.
- Immigration offsets the effects temporarily, but immigrants also age.
- Immigrants from high-family-number countries (e.g., India) reduce family size over generations.
Example:
2nd and 3rd generation Indian migrants to the UK now have an average of 2.4 children compared to 4.4 within India.
Note:
Population ageing and falling fertility rates are global occurrences, so future migrant profiles may change.
Migration
Impact on Population Structure
Migration can lead to imbalances in population structures. For example, the UAE has significantly more males than females due to the migration of males to work in the oil, gas, and construction industries.
UAE Population Pyramid
- Males (25-39 years): 29% of the population.
- Females (25-39 years): 10.5% of the population.
Effects of Rapid Population Growth Due to Migration
- Increased pressure on healthcare and schools.
- Shortage of housing.
- Increased traffic congestion.
- Increased water and air pollution.
- Shortage of food and clean water.
Population Growth in LIC and MIC Cities
Characteristics
- Rapid growth, particularly in Asia and Africa.
- Rural-urban migration dominated by younger age groups.
Consequences
- High birth rates.
- Pressure on jobs and services.
- Reduced dependency ratio.
Example:
In Lagos, Nigeria, the largest age groups are young children (0-4 years) and young adults (20-29 years).
HIC Cities
- Slower population growth.
- Lower birth rates.
- Higher dependency ratio.
Example:
In Tokyo, Japan, the largest age groups are older adults between 45 and 50 years.
Natural Change
Natural population change occurs when birth and death rates differ in a place. It can be calculated as follows:
$$ \text{Natural Change in Population} = \left( \frac{\text{Birth Rate}}{1000} - \frac{\text{Death Rate}}{1000} \right) \times 1000 $$
Example:
For the USA in 2020: $$ \text{Natural Change in Population} = \left( \frac{11.96}{1000} - \frac{8.95}{1000} \right) \times 1000 = 0.30% $$
Conclusion
Understanding changing populations is essential for grasping the dynamics of human geography. By examining demographic transitions, ageing populations, migration, and natural population changes, we gain insights into the complexities of population structures and their impacts on society.