Growing cities bring jobs and services together, and also problems of space, cost and fairness. Here are the main challenges and the main responses, each with debated effects. They build on the models of cities you have studied.
Key idea
| Response | What supporters say | What critics say |
|---|---|---|
| Urban growth boundary (Portland, Oregon, since the 1970s) | Protects farmland, encourages transit and infill | Limits land for building, which can raise housing prices |
| New urbanism | Walkable streets, shops near homes, less driving | Can be costly; some projects become high-priced enclaves |
| Public transit | Moves many people in little space; helps those without cars | Expensive to build; works best at high density |
| Redevelopment of old areas | New investment, jobs and housing | Can displace long-time residents |
Why it works
Gentrification is the arrival of higher-income residents and investment in an older, lower-income neighborhood. The word was coined in 1964 by the sociologist Ruth Glass, describing London. Worldwide, about 1.1 billion people lived in slums or informal settlements in 2022 (UN-Habitat estimate), mostly in fast-growing cities of Africa and Asia.
Worked example: Name the trade-off
- Benefit: farmland and open space are protected, and development is steered closer to existing roads and transit.
- Cost: less land for new homes can push housing prices up.
Answer: It protects farmland but may raise housing costs.
Worked example: Two views of one change
- A homeowner or a new business may welcome rising values, new shops and safer streets.
- A long-time renter may be unable to afford to stay.
Answer: Gentrification: investment and new services, and displacement pressure on renters.
Common mistake