Key Idea: Most marks in topic 8.2 come from sustainable urban planning and how urban expansion harms ecosystems. At HL, also learn rural-urban migration and the models of ecological urban planning.
1. Sustainable urban planning (most marks)
- Plan for public transport, green space, mixed land use, and saving energy and water.
- Curitiba, Brazil, opened bus rapid transit in 1974: buses in their own lanes, far cheaper than a metro.
- Trees cool streets and clean the air, but in Portland, Oregon, poorer areas have fewer trees.
2. Urban expansion and the environment
- Sprawl covers farmland and habitat, splits it up, and adds run-off, heat and pollution.
- Pudong, Shanghai, was farmland and canals in 1990; about 5.7 million people lived there by 2020.
- Freeways cut off Los Angeles's mountain lions; a wildlife crossing over the 101 has been built since 2022.
3. Migration and HL ideas
- A city is a system: food, water and energy go in; waste, heat and pollution come out.
- The world's urban population passed the rural population in 2007; about 58% of people lived in cities in 2025.
- At HL: ecological planning (Vauban, the 15-minute city), the doughnut model and green architecture.
How it is examined:
| Question | How to score |
|---|---|
| [1] to [2] Describe an urban change from data or photos | Direction, values and dates; name the change. |
| [1] Calculate a rate of rural depopulation | (start − end) ÷ start x 1000, with the unit. |
| [2] to [4] Identify impacts of sprawl on ecosystems | Habitat loss, fragmentation, run-off, pollution: one per mark. |
| [2] Outline the benefits of greening a city | Cooler streets, cleaner air, less flooding, better health. |
| [9] To what extent is urban planning shaped by global or local factors? | Global goals v local land, money and people; named cities; a judgement. |
| [4] Identify ways to cut the impact of rural-urban migration | Public transport, compact homes, green space, clean energy and water. |
Key terms, one line each:
| Term | In one line |
|---|---|
| Urbanization | a rising share of a population living in towns and cities |
| Rural-urban migration | people moving from the countryside to towns and cities |
| Suburbanization | people and businesses moving out to the edge of a city |
| Urban sprawl | the unplanned spread of a city onto the land around it |
| Sustainable urban planning | designing a city to meet people's needs while using fewer resources |
| Urban growth boundary | a line around a city beyond which new building is limited |
| Doughnut model | a city should meet everyone's basic needs without passing Earth's limits |
Last-minute check: answer, then tap to see.
What makes Vauban, in Freiburg, low-car? Cars park at the edge and a tram runs to the centre; about 7 in 10 households had no car in 2009.
What is Amsterdam's circular goal? Halve its use of new raw materials by 2030; fully circular by 2050.
Name one green feature of BedZED, London (2002). Much of its steel was reused from demolished buildings.
Why can new parks hurt poorer people? They push up house prices, so pair them with affordable homes.
In 1990 most of Pudong, across the river from central Shanghai, was farmland and canals. By 2020 about 5.7 million people lived there. Explain how the rapid growth of a city can harm the ecosystems around it.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
Exam tips
- Link each impact to the growth of the city, not to cities in general.
- Name a real city for every strategy: Curitiba, Portland, Vauban.
- For a rate of depopulation, show the working and give the unit.
- Use the AHL models in a [9]: the doughnut, the circular economy and green buildings.