World cities: categories and causes

What is Urban Growth? 🌆

Urban growth is the increase in the size, population, and economic activity of cities. Think of a city as a growing tree: the roots (infrastructure) spread out, the trunk (transport links) thickens, and the canopy (businesses, homes) expands. When more people move in, the city’s “canopy” gets denser.

Hierarchy of Urban Areas 🗺️

Cities are ranked in a hierarchy based on their size, economic power, and influence. The classic model is:

1. Global Cities – The world’s super‑hubs (e.g., New York, London).
2. Regional Cities – Major centres within a country (e.g., Manchester, São Paulo).
3. National Cities – Capital or key economic centres (e.g., Canberra, Nairobi).
4. Local Cities – Smaller towns with local importance (e.g., small provincial capitals).

Each level serves different functions, much like the layers of an onion.

Causes of Urban Growth 🚀

• Economic Pull: Jobs, higher wages, and better services attract people. Example: The tech boom in Bengaluru drew talent from across India.
• Political Pull: Government investment, stability, and policy incentives. Example: The “Smart City” initiative in many Indian cities.
• Social Pull: Education, healthcare, and cultural amenities. Example: Paris’s universities and museums.
• Push Factors: Rural poverty, lack of jobs, or environmental hazards push people toward cities.

Mathematically, growth can be expressed as a percentage change: Δ% = ((P₂ - P₁)/P₁) × 100 where P₁ is the initial population and P₂ is the later population.

World City Categories 🌍

Exam Tips for A‑Level Geography 📚

• Use the hierarchy diagram to show relationships between city types.
• Explain push and pull factors with specific examples.
• Include statistics (e.g., population growth rates) to support arguments.
• Remember to discuss environmental impacts of rapid urbanisation.
• Use the Causes–Consequences–Solutions structure for essay questions.

Good luck, and keep your notes colourful and clear! 🎓