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Urbanisation and urban growth

IB Environmental Systems and Societies • Unit 8

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The urbanisation process

Big idea: Urbanisation is one of the most significant global trends. More than half of humanity now lives in cities, with rapid growth continuing in developing countries.

Global urbanisation trends

  • Current level: ~56% of world population is urban (2023)
  • Projected: 68% urban by 2050
  • Historical: Only 30% urban in 1950; 14% in 1900
  • Megacities: 33 cities now have >10 million people
  • Fastest growth: Sub-Saharan Africa and South Asia

Causes of urbanisation

  • Rural-to-urban migration: People move seeking better opportunities
  • Natural increase: Urban birth rates often exceed death rates
  • Reclassification: Rural areas become classified as urban as they grow
  • Economic development: Industrialisation concentrates jobs in cities

Push and pull factors

Push factors (leave rural)

  • Lack of employment
  • Poor services (healthcare, education)
  • Agricultural mechanisation
  • Land degradation/climate impacts
  • Conflict and insecurity

Pull factors (attract to urban)

  • Job opportunities
  • Better services and infrastructure
  • Higher wages
  • Social and cultural opportunities
  • Perceived better quality of life
Exam tip: Questions often ask for push AND pull factors. Give specific examples and explain HOW each factor drives urbanisation.

Challenges and opportunities of urbanisation

Big idea: Urbanisation creates both problems and opportunities. Well-managed cities can be more sustainable than sprawling rural populations; poorly managed growth leads to slums, pollution, and resource stress.

Challenges of rapid urbanisation

  • Housing: Informal settlements/slums, overcrowding, homelessness
  • Infrastructure strain: Water, sanitation, electricity, transport overloaded
  • Unemployment: Informal economy, underemployment, poverty
  • Pollution: Air, water, noise, solid waste
  • Health: Disease spread, poor sanitation, limited healthcare access
  • Social issues: Crime, inequality, social fragmentation

Opportunities of urbanisation

  • Efficiency: Concentrated populations can share infrastructure more efficiently
  • Innovation: Cities are hubs of creativity, education, and economic growth
  • Services: Easier to provide healthcare, education, utilities to dense populations
  • Lower per-capita emissions: Dense cities can have lower footprints than sprawl
  • Social mobility: More opportunities for education and employment
  • Cultural exchange: Diversity drives innovation and social progress
Cities cover only ~3% of Earths land surface but house 56% of people, consume 75% of resources, and produce 70% of CO₂ emissions. Urban sustainability is crucial for global sustainability.
Exam tip: Urban questions often require balanced arguments. Acknowledge BOTH challenges and opportunities before evaluating solutions.

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