Key Idea: Topic 13.2 is about how urban systems change over time — how cities first explode in size, and then reshape themselves as industry leaves and people move out and back in. It pulls together two ideas: 13.2.1 — urbanisation, megacities & urban growth: the rising share of people in cities (urbanisation) and the rising number in any one city (urban growth), driven by natural increase + rural-urban migration — fastest in Africa and Asia (Lagos, Kinshasa), and the management challenges rapid growth creates. 13.2.2 — deindustrialisation, gentrification & urban change: how manufacturing decline triggers centrifugal outward movement (suburbanisation, counter-urbanisation), then a centripetal bounce-back (re-urbanisation, gentrification) — with winners and losers at every stage. This is an Option G topic, examined on Paper 1. SL answers 2 options, HL answers 3 (same questions). Expect short data-response reads off an urban-growth graph, a cluster of structured parts (State, Estimate, Suggest, Outline, Describe, Explain), and a [10] markband essay (Examine / To what extent).
🏙️ 13.2.1 — Urbanisation, megacities & urban growth
Urbanisation is the rising proportion of people living in towns and cities; urban growth is the rising number of people in a city — a country can be fully urbanised and still see its cities grow. A megacity has over 10 million people (Tokyo, Lagos, Mumbai). Cities grow from two engines at once: natural increase (a youthful migrant population with high birth rates) and rural-urban migration (push and pull factors). The skill examiners test is reading a line graph or table of urban share rising over time — State / Estimate / Identify a value with its units (% urban) — then Suggest or Explain causes, matched to the type (demographic, economic or social) the command asks for.
Causes of rapid urban growth (sort them by type)
| 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 migrants in |
| Social | Schools & hospitals | Families move for education and healthcare the countryside lacks |
| Social | Rural push factors | Drought, conflict or land shortage drive people off the land |
Not every city keeps booming. Tokyo, the world's largest, is now barely growing — Japan's birth rate is very low and rural-urban migration has run its course. Across Europe and North America, urbanisation is near its ceiling (75-85%), so the share rises slowly. Growth slows when birth rates fall, the rural population to draw on runs out, or people move back out (counter-urbanisation). On a question asking for ONE cause type (social / economic / demographic), a cause of another type scores zero.
Key terms — urbanisation & growth
- 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 / pull factors — things driving people OUT of rural areas / drawing them INTO cities.
- Informal settlement — self-built housing (slum) where growth outpaces formal house-building.
A typical Paper 1 figure: read the key first, follow ONE line, read its value off the left axis and quote the units (% urban).
🔒 Interactive diagram
Explore the labelled diagram, charts and maps for this topic in study mode.
🔄 13.2.2 — Deindustrialisation, gentrification & urban change
Deindustrialisation is the decline of manufacturing industry — factories close, jobs vanish, land falls derelict. It sets off a chain of urban change: people and money first move outwards (centrifugal — suburbanisation, then counter-urbanisation), hollowing out the inner city; later they move back in (centripetal — re-urbanisation and gentrification) as wealthier residents and investment return. The examiner skill is reading a falling-employment line graph (Describe the trend), then Explaining why manufacturing declines (marked 3 + 3 with a named city), and tracking both directions of movement plus the winners and losers they create.
Why manufacturing declines, and what follows
| Driver of decline | How it forces decline / change |
|---|---|
| Cheaper labour & land abroad | Globalisation lets firms relocate to lower-wage countries, so domestic factories close |
| Automation & new technology | Machines replace assembly-line workers, so far fewer jobs survive |
| Cramped, costly city sites | Old inner-city factories cannot expand; high rents make them uncompetitive |
| Shift to a service economy | Investment moves to offices, finance and tech; manufacturing's job share shrinks |
Two directions of urban change
| Centrifugal (outward) | Centripetal (inward) | |
|---|---|---|
| What it is | People & activity move OUT from the centre | People & activity move BACK towards the centre |
| Processes | Suburbanisation (to the edge), then counter-urbanisation (to the countryside) | Re-urbanisation and gentrification (wealthier residents return) |
| Trigger & timing | Deindustrialisation usually triggers the outward move | The inward bounce-back comes decades later |
| Effect on inner city | Ageing population, vacant housing, lost tax revenue | Renovated housing and rising land values — but displacement |
Key terms — urban change
- Deindustrialisation — the decline of manufacturing industry (closures, lost jobs, derelict land).
- Centrifugal movement — people/activity moving outwards (suburbanisation, counter-urbanisation).
- Suburbanisation — outward spread of people and housing into the edge of the city.
- Counter-urbanisation — people leaving the city altogether for smaller towns and the countryside.
- Centripetal movement — people/activity moving back towards the centre.
- Re-urbanisation — people and investment returning to the inner city after decline.
- Gentrification — wealthier residents renovate a run-down inner-city area, raising land values.
Important: The benefits of urban change are uneven. Winners: incoming wealthier residents and developers (renovated housing, rising values) and the city (a higher tax base, restored buildings, new shops and culture). Losers: long-standing low-income residents priced out by rising rents, and local shops replaced by upmarket ones. Regeneration on paper can mean displacement for the original community — so an essay must weigh both sides and name a city (Detroit, Manchester, London, Barcelona).
✍️ IB-style questions
Explain two reasons why some cities continue to grow very rapidly while others have stopped growing.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
To what extent have the world's rapidly growing cities been able to keep their infrastructure in step with the scale and pace of urban growth?
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
✅ Quick self-check
Tap each card to reveal the answer.
Urbanisation vs urban growth — what's the difference? Urbanisation is the rising proportion of people who are urban; urban growth is the rising number in a city. A fully urbanised country can still see its cities grow.
What two processes make a city grow rapidly? Natural increase (a youthful population with high birth rates) and rural-urban migration (people pulled in by jobs, schools and hospitals) — fastest in Africa and Asia.
Centrifugal vs centripetal movement? Centrifugal = outward (suburbanisation, counter-urbanisation); centripetal = inward (re-urbanisation, gentrification). Deindustrialisation drives the outward move; gentrification is the inward bounce-back.
Why does manufacturing decline in cities? Cheaper labour/land abroad (globalisation), automation, cramped costly sites and a shift to a service economy — e.g. the collapse of car-making in Detroit.
Why are the benefits of urban change 'uneven'? Regeneration and new service jobs help some areas/groups, but others face displacement (priced-out residents) or lasting decline where no investment follows.
🎯 Highest-yield exam reminders
Exam Tips
- Urbanisation = the SHARE; urban growth = the NUMBER; megacity = over 10 million.
- Two engines of growth: natural increase + rural-urban migration (push/pull). Match the cause TYPE the command asks for — social, economic or demographic.
- Read the figure first: follow ONE line, quote a value with its UNITS (% urban). State = exact value; Estimate = read between marks; Identify = name the place/category.
- Centrifugal = outward (suburbanisation, counter-urbanisation); centripetal = inward (re-urbanisation, gentrification). Deindustrialisation triggers the outward move.
- Explain [6] on decline is marked 3 + 3: a valid reason + development + a NAMED city (e.g. Detroit) for each.
- On the [10] essay: weigh BOTH sides (gains vs costs, or growth vs infrastructure), cover both directions of movement, name cities, and finish on 'uneven' as the justified judgement.