5.3 Population
Population growth is driven by birth rates, death rates, and migration—understanding these dynamics explains why countries develop differently and face different economic challenges.
What You'll Learn
Population Growth: How birth rate, death rate, and migration drive population change
Natural Change: Why LEDCs have high birth rates and MEDCs have low ones
Optimum Population: The balance between population size and resources (not just "lots of people")
Population Pyramids: How to read them and what they tell you about a country's development stage
Economic Effects: Ageing populations, falling birth rates, and migration impacts on the economy
Population Growth
The Three Drivers of Population Change
Population is everyone living in a country. The population growth rate measures how fast it's changing, expressed as a percentage. Three things affect it:
A higher birth rate and lower death rate both increase population. More immigration than emigration also increases it. But here's the important bit: all countries have different growth rates.
What's the real-world pattern?
LEDCs like Niger, Mali, and Zambia have the highest growth rates (sometimes above 4% per year). MEDCs like Italy and Japan have very low or even negative growth rates—more people dying than being born.
Why Do Growth Rates Differ So Much?
There are two broad causes: migration and natural population change (birth minus death rates). Let's focus on the natural causes—that's where the real story is.
Practice: Spot the Difference
Immigration = people moving into a country. Emigration = people moving out. Examiners love testing whether you know the difference. If you mix them up, you lose marks.
Natural Causes of Population Change
Why Death Rates Fell (And Keep Falling)
All countries have experienced falling death rates over the past 200+ years. Here's what caused it:
- The Agricultural Revolution: Better farming techniques meant more food, healthier diets, fewer people starving
- Medicine & Healthcare: Vaccines, antibiotics, better hospitals—people don't die from infections as easily
- Technology & Transport: Railroads, roads, trucks—food and goods reached isolated areas. Wealthier populations have better life expectancy
- Housing & Sanitation: Clean water, indoor toilets, sewers—diseases spread less. People live longer
The result: death rates have fallen everywhere, but especially in MEDCs where these improvements happened first and most completely.
But Birth Rates Went Different Ways
In LEDCs, birth rates stayed high because:
- No contraception: Limited access to family planning and birth control
- More women survived childbirth, so families could be bigger without tragedy
- Cultural and economic reasons: