Topic 3 of 3Cambridge O Levels

Population & Migration

Population growth, demographic transition model, and migration

Population growth depends on: birth rate, death rate, and migration. Natural increase = birth rate − death rate.

The Demographic Transition Model (DTM) — 5 stages:

High stationary: High birth rate, high death rate → low growth (pre-industrial)

Early expanding: High birth rate, falling death rate → rapid growth (better healthcare)

Late expanding: Falling birth rate, low death rate → slower growth (urbanisation, education)

Low stationary: Low birth rate, low death rate → stable population (developed countries)

Declining: Birth rate below death rate → population shrinks (ageing population)

Population pyramids: Wide base = young population (stage 2-3). Narrow base = ageing population (stage 4-5).

Migration: **Push factors** (poverty, war, natural disasters). **Pull factors** (jobs, safety, education). **Rural-urban migration** drives urbanisation in developing countries.

Population policies: Pro-natalist (encourage births — France). Anti-natalist (discourage — China's former one-child policy).

Key Points to Remember

1Natural increase = birth rate − death rate
2DTM: 5 stages from high-high to declining
3Push factors drive people away, pull factors attract
4Population pyramids show age-sex structure

Pakistan Example

Pakistan's Population Boom — Stage 2-3 of the DTM

Pakistan (230+ million, 2024) is in DTM Stage 2-3: death rates have fallen (better healthcare, Lady Health Workers programme), but birth rates remain high (cultural preference for large families, low female literacy in rural areas). Rural-to-urban migration floods Karachi with ~400,000 new residents yearly.

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