The big idea: Urbanisation is the rising share of people living in towns and cities — the % of a country's population that is urban.
Don't confuse it with urban growth, which is the rise in the number of people living in a city. A city can keep growing in size even after a country is fully urbanised.
A megacity is a city with more than 10 million people (e.g. Tokyo, Lagos, Mumbai). The number of megacities has risen fastest in Africa and Asia.
Key terms for this micro
- Urbanisation — the increasing proportion of a population living in urban areas.
- Urban growth — the increase in the number of people living in a city.
- Megacity — a city with a population over 10 million.
- Natural increase — births minus deaths; a youthful city population grows itself.
- Rural-urban migration — people moving from the countryside to the city.
- Push factors — things driving people OUT of rural areas (poverty, drought, few jobs).
- Pull factors — things drawing people INTO cities (jobs, schools, hospitals).
Two engines of urban growth: A city grows from two sources at once:
Natural increase — a youthful migrant population has high birth rates, so the city grows from within.
Rural-urban migration — people pulled in by city opportunities. Together these make cities in Africa and Asia grow fastest today.
How this is tested: Paper 1 Option G opens with a data-response on an urban-growth graph, an infographic of the fastest-growing cities, or a map of a megacity's spread. You State or Identify a value (the fastest-growing city, the year the world became 50% urban, a continent's share) or Estimate a distance off a map scale. Always read the correct axis or scale and quote the units.
| Region | 1980 | 2020 | Projected 2050 |
|---|---|---|---|
| North America | 74 | 83 | 89 |
| Latin America & Caribbean | 65 | 81 | 88 |
| Europe | 67 | 75 | 84 |
| Asia | 27 | 51 | 66 |
| Africa | 27 | 44 | 59 |
| World | 39 | 56 | 68 |
State vs Estimate vs Identify: State = give the exact value shown (e.g. read 51 straight off the table).
Estimate = a sensible value read between marks or off a map scale.
Identify = name the place, feature or category the data points to.
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Cities grow because more people are added than leave — through natural increase (births over deaths) and rural-urban migration.
Examiners split the causes into demographic, economic and social, and a question often asks for one type only — read the command carefully, because a 'social' answer earns nothing on an 'economic' question.
| Type | Cause | How it grows the city |
|---|---|---|
| Demographic | Natural increase | A youthful migrant population has high birth rates, so the city grows from within |
| Economic | Better-paid jobs | Factories and services pay more than rural farming, pulling in migrants |
| Social | Schools & hospitals | Families move for education and healthcare unavailable in the countryside |
| Social | Rural push factors | Drought, conflict or land shortage drive people off the land |
Social vs economic vs demographic
- Demographic — natural increase (a youthful, high-birth-rate population).
- Economic — jobs and higher wages in factories and services.
- Social — schools, hospitals, family ties, escaping rural hardship.
- On a question asking for ONE type, a cause of another type scores zero.
Always give the mechanism: Don't just name a cause — explain how it grows the city. Better hospitals -> families migrate for healthcare -> more people in the city. And match the type the command asks for.
Why some cities slow — Tokyo and Europe: Not every city keeps booming. Tokyo, the world's largest city, is now barely growing or shrinking — Japan's birth rate is very low and rural-urban migration has run its course.
Across much of Europe and North America, urbanisation is already near its ceiling (75-85%), so the urban share rises only slowly. Growth slows when birth rates fall, the rural population to draw on runs out, or people start moving back out (counter-urbanisation).
The challenge of rapid growth: When a city grows faster than its infrastructure can keep up, services are overwhelmed. New arrivals build informal settlements (slums) on cheap, often risky land, with no piped water, sewerage or secure jobs.
The core management challenges are housing, clean water and sanitation, jobs, transport/congestion, and waste and pollution — all of them strained by the scale and pace of growth.
| City | Growth story | Use it for |
|---|---|---|
| Lagos, Nigeria | Africa's largest city, ~15-20m and rising fast; huge informal settlements (Makoko) | Rapid growth + housing/water stress |
| Kinshasa, DR Congo | One of the fastest-growing cities on Earth, driven by high natural increase | Pace of growth + jobs/services gap |
| Mumbai, India | Dharavi is one of Asia's largest informal settlements; severe congestion | Slums + transport/sanitation |
| Tokyo, Japan | World's largest city but now barely growing - low birth rate | Where growth has SLOWED |
How this is tested - the [10] Examine essay: Paper 1 Option G ends with a 10-mark markband essay. Two recurring versions:
Examine the management challenges of rapidly growing cities, and To what extent has urban growth been matched by better infrastructure.
Top band needs: accurate terms, two or more developed challenges with a named city, a weighing of how growth's scale and pace drive them (or how far infrastructure has kept up), and a justified conclusion.