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.