6. Changing Population
6. Changing Populations
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6.1.1 Patterns and trends in global population growth.
6.1.2 Reasons for the growth and decline of a country’s population: fertility rate, birth rate, death rate, natural increase, migration.
6.1.3 An evaluation of the impacts of pro-natalist and anti-natalist policies on birth rates.
6.1.4 The demographic transition model (DTM) and its strengths and limitations.
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6.2.1 Factors influencing population structures: natural increase and net migration.
6.2.2 The causes and impacts of youthful and ageing population structures, and an evaluation of their impacts.
6.2.3 One detailed specific example of a named country to include:
• reasons for population growth or decline
• the impacts of a population policy (pro or anti-natalist). -
6.3.1 Types of migrant: economic migrant, asylum seeker and refugee.
6.3.2 Causes of migration, to include push and pull factors.
6.3.3 The impacts of migration on the migrant, their country of origin and the destination country.
6.3.4 An evaluation of the strategies and techniques used to manage international migration.
6.3.5 One detailed specific example to include:
• push and pull factors of a named international migration (named to include the country of origin and destination country)
• the impacts of the migration (on the migrants, their country of origin and the destination country)
• how the migration is managed; including sustainable.
6.1 Introduction to Population
Population change means how the number of people living in a place increases or decreases over time.
This depends on births, deaths, immigration (people arriving) and emigration (people leaving).
To help you understand this, imagine that the population is like water in a bathtub.
Birth rate is like how fast the taps are running — it measures how many babies are born each year for every 1 000 people.
Death rate is like how wide the plughole is open — it measures how many people die each year for every 1 000 people.
Natural increase happens when the taps flow faster than the plughole drains (birth rate > death rate).
Natural decrease happens when the plughole drains faster than the taps flow (death rate > birth rate).
Immigration adds extra water from the shower, and emigration lets water spill out — these also change the total level.
6.1.1 Patterns and trends in global population growth.
The world’s population has changed dramatically over time. For most of history, the number of people grew slowly — but in the last few hundred years, it has grown very quickly.
Before 1800: Low and steady
High death rates and low life expectancy meant population grew slowly. Many people died from disease and poor food supplies.
1800–1950: Gradual increase
Industrial Revolution improved farming, medicine, and transport. Birth rates stayed high while death rates began to fall.
1950–today: Rapid growth (exponential increase)
Big fall in death rates, especially in LICs. Better healthcare, food and sanitation meant people lived longer.
Today (2020s): Slower growth
Birth rates are now falling in many countries as education and living standards rise. Population is still growing, but more slowly.
Population Trends by Continent
800–1900: Slow Growth
In 1800, only about 1 billion people lived on Earth.
Most people lived in Asia and Europe.
Birth rates were high, but many people died young from disease or hunger.
Population in Africa and South America grew slowly because of poor healthcare.
All countries were small and poor (LICs). Growth was very slow.
1900–1950: Growth Starts to Increase
In Europe and North America, factories, clean water, and better medicine reduced deaths.
Birth rates stayed high, so population began to grow.
In Asia and South America, growth also started to rise slowly.
HICs grew first. LICs and MICs started to catch up later.
1950–2000: Population Explosion
After 1950, the world’s population grew very fast — from 2.5 to 6 billion.
LICs and MICs in Asia, Africa, and South America grew quickly because death rates fell but birth rates stayed high.
HICs in Europe and North America slowed down — smaller families, more education, and ageing populations.
Most population growth happened in developing countries (LICs and MICs).
2000–2025: Slower Growth, Uneven Spread
The world passed 8 billion people in 2023.
Africa is growing fastest — countries like Nigeria and Ethiopia have many young people.
Asia is growing more slowly — China and Japan are even shrinking.
Europe is ageing and has very low birth rates.
Most new population growth now happens in LICs, especially in Africa.
2025–2100: Growth Will Slow Down
The world may reach 10 billion people by about 2080, then stop growing.
Africa will continue to grow fastest.
Asia will start to lose population after 2050.
Europe will keep shrinking.
HICs will get older and smaller, while LICs will stay young and grow.
Future growth will mostly come from Africa and parts of South Asia.
6.1.2 Reasons for the growth and decline of a country’s population
Understanding Population Change
The number of people living in a country changes because of births, deaths, and migration.
When more people are added than removed, the population grows.
When more people die or leave than are born or arrive, the population falls.
Crude Birth Rate
Crude birth rate is the number of live babies born each year for every 1 000 people in a country.
It is called crude because it includes everyone — it doesn’t matter how old they are or whether they can have children.
A high crude birth rate means the population is growing quickly.
A low crude birth rate means growth is slowing or stable.
Examples:Niger – around 45 births per 1 000 people (very high, LIC).
Japan – around 7 births per 1 000 people (very low, HIC).
Crude Death Rate
Crude death rate is the number of deaths each year for every 1 000 people in a country.
It also includes the whole population, not just older people.
A high crude death rate can be caused by poor healthcare, war, or famine.
A low crude death rate shows good medical care, food, and living conditions.
Examples:Afghanistan – around 12 deaths per 1 000 people (LIC, limited healthcare).
UK – around 9 deaths per 1 000 people (HIC, ageing population).
Natural Increase/Decrease
Natural increase and natural decrease describe how a population changes without including migration.
Natural increase happens when the birth rate is higher than the death rate.
The population grows because more people are being born than dying.
This is common in LICs and MICs, such as Nigeria or India.
Natural decrease happens when the death rate is higher than the birth rate.
The population gets smaller because more people are dying than being born.
This is common in HICs, such as Japan or Germany, where people live longer but have fewer children.
Birth rate – Death rate = Natural increase (or decrease).
Total Fertility Rate
Total fertility rate means the average number of babies born to each woman during her lifetime.
If TFR is above 2.1, the population usually grows (replacement level).
If TFR is below 2.1, the population will shrink over time unless immigration increases.
Examples:Nigeria – TFR ≈ 5.1 (rapid growth).
China – TFR ≈ 1.2 (declining population).
Migration
Migration is when people move from one place to another to live or work.
Immigration (arriving) increases population size.
Emigration (leaving) decreases population size.
Examples:
Canada grows because many immigrants move there for work.
Syria has lost population as people emigrate to escape war.
6.1.4 The demographic transition model (DTM) and its strengths and limitations.
Stage 1 – High Stationary
Description:
Both birth rate and death rate are very high.
Population size stays small and changes very little.
Reasons:
Poor healthcare and sanitation.
Frequent disease, famine, and war.
No family planning; many children die young, so families have more.
Example:
No country today, but some isolated tribal groups (e.g. parts of the Amazon rainforest).
Stage 2 – Early Expanding
Description:
Death rate falls quickly, but birth rate stays high.
Population grows very fast (population explosion).
Reasons:
Better food supply and medicine reduce deaths.
Clean water and sanitation improve.
Birth rates stay high because people still expect many children to die.
Example:
Niger, Afghanistan, Chad.
Stage 4 – Low Stationary
Description:
Both birth rate and death rate are low and balanced.
Population growth is very small or stable.
Reasons:
High living standards and strong healthcare.
Most people live in cities.
Parents often wait longer to have children.
Example:
UK, USA, France.
What is the DTM?
The Demographic Transition Model (DTM) shows how a country’s birth rate, death rate, and total population change over time as it develops.
It has five stages, from very poor countries with high birth and death rates to very rich countries with ageing or declining populations.
Key Idea
As countries develop, death rates fall first, followed later by birth rates.
This process causes the population to rise quickly, then slow, and finally stabilise or decline.
Stage 5 – Natural Decrease
Description:
Birth rate is very low, often lower than the death rate.
Population begins to shrink or age.
Reasons:
Many older people but fewer births.
High cost of living, small families, and career-focused lifestyles.
Low immigration may cause population decline.
Example:
Japan, Germany, Italy.
Strengths and Limitations of the Demographic Transition Model
Strengths
Easy to Understand – The model clearly shows how birth and death rates change as a country develops.
Useful Comparison Tool – It helps compare countries at different levels of development (LIC, MIC, HIC).
Explains Population Growth – It shows why populations grow quickly in some stages and slow down in others.
Based on Real Evidence – The model was built using real data from countries such as the UK during industrialisation.
Predictive Power – It helps show what might happen next as a country develops (e.g. when birth rates might fall).
Stage 3 – Late Expanding
Description:
Birth rate starts to fall, death rate remains low.
Population continues to grow but more slowly.
Reasons:
Family planning and contraception become available.
More education and jobs for women.
Children are expensive; families choose to have fewer.
Example:
India, Mexico, Brazil.
Limitations
Based on European Experience – The model was made from Western countries and may not fit every country’s pattern.
Does Not Include Migration – It only looks at births and deaths, not immigration or emigration.
No Time Scale – It does not show how long each stage takes; some countries move faster or slower than others.
Ignores Government Policies – Population changes can be affected by laws (e.g. China’s One-Child Policy) which the model doesn’t include.
Does Not Show Population Decline from Other Causes – War, disease, or natural disasters can reduce population suddenly, but these are not part of the model.
Not All Countries Reach Stage 5 – Some developing countries may not follow all five stages exactly.