G29: Urbanisation and Megacities
The global pattern of urban change, push and pull factors driving rural-urban migration, natural increase within cities, and the emergence of megacities.
🌍 The Global Pattern of Urban Change
Definition: Urbanisation is the increase in the proportion of people living in urban areas (towns and cities) compared to rural areas (countryside). It is caused by rural-urban migration and natural increase within cities.
The world has undergone a dramatic shift from rural to urban living:
- In 1950, only 30% of the world's population lived in urban areas
- By 2007, for the first time in history, more people lived in cities than in rural areas
- By 2025, approximately 57% of the world's population is urban
- By 2050, this is projected to reach 68% (an additional 2.5 billion urban residents)
- Nearly 90% of this growth will occur in Africa and Asia
| Region | Current Urban % | Projected 2050 | Rate of Urbanisation |
|---|---|---|---|
| North America | 82% | 88% | Slow (already highly urbanised) |
| Latin America | 81% | 87% | Slow (already highly urbanised) |
| Europe | 74% | 80% | Slow (already highly urbanised) |
| Africa | 44% | 57% | Rapid (fastest urbanising continent) |
| Asia | 51% | 64% | Rapid (largest absolute growth) |
Key Fact: HICs (High-Income Countries) are already highly urbanised (over 75%). The fastest urbanisation is happening in LICs (Low-Income Countries) and NEEs (Newly Emerging Economies), where rates of urban growth can exceed 4% per year.
🚜 Push and Pull Factors
Key Concept: Rural-urban migration is driven by push factors (negative conditions that drive people away from rural areas) and pull factors (positive attractions that draw people to cities). People weigh up both sets of factors when deciding to move.
Push Factors (Rural Areas)
- Low agricultural wages: Farming incomes are very low, often less than $2 per day
- Mechanisation: Machines replace farm workers, reducing rural employment
- Drought and famine: Climate change and environmental degradation make farming unreliable
- Lack of services: Poor healthcare, education, electricity and clean water
- Poor housing: Inadequate shelter with no sanitation
- Natural disasters: Flooding, hurricanes and droughts devastate rural communities
- Conflict: Civil war and violence displace rural populations
- Overpopulation: Too many people for available land and resources
Pull Factors (Urban Areas)
- Employment: More jobs available in industry, services and informal sector
- Better wages: Urban incomes are typically 3-5 times higher than rural incomes
- Education: Schools, colleges and universities provide opportunities for children
- Healthcare: Hospitals and clinics offer better medical care
- Services: Electricity, clean water, sanitation and telecommunications
- Social opportunities: Entertainment, culture, religion and community
- Family links: Joining relatives who have already moved to the city
- Perception: Cities are seen as exciting, modern and full of opportunity
| Type | Factor | Rural (Push) | Urban (Pull) |
|---|---|---|---|
| Economic | Income | Very low wages from farming | Higher wages from industry and services |
| Social | Education | Few schools; long distances | Schools, colleges, universities |
| Social | Healthcare | No hospitals; limited clinics | Hospitals, clinics, pharmacies |
| Environmental | Housing | Poor quality; overcrowded | Better housing (perceived) |
| Environmental | Services | No electricity or clean water | Utilities and infrastructure |
👶 Natural Increase within Cities
Definition: Natural increase is the growth of the urban population through births exceeding deaths. It accounts for roughly 60% of urban growth in LICs and NEEs, with migration accounting for the remaining 40%.
Natural increase occurs because:
- Younger population: Migrants to cities are typically young adults of childbearing age, so birth rates are naturally higher
- Higher birth rates: In many LICs and NEEs, birth rates remain high (3-6 children per woman) even as people move to cities
- Lower death rates: Urban areas have better healthcare, nutrition and sanitation, reducing infant mortality and increasing life expectancy
- Cultural factors: Some migrant communities retain traditional values favouring larger families
- Lag in demographic transition: Death rates fall quickly with improved healthcare, but birth rates take longer to decline
Natural Increase = Birth Rate - Death Rate
When birth rate exceeds death rate, population grows naturally. In rapidly urbanising cities like Lagos (birth rate ~36 per 1,000; death rate ~10 per 1,000), natural increase adds approximately 2.6% to the population each year. Combined with migration, Lagos grows by over 3% annually - adding roughly 77 people per day through natural increase alone.
When birth rate exceeds death rate, population grows naturally. In rapidly urbanising cities like Lagos (birth rate ~36 per 1,000; death rate ~10 per 1,000), natural increase adds approximately 2.6% to the population each year. Combined with migration, Lagos grows by over 3% annually - adding roughly 77 people per day through natural increase alone.
🏙️ The Emergence of Megacities
Definition: A megacity is an urban area with a population of 10 million or more. In 2020, there were approximately 34 megacities worldwide, most located in LICs and NEEs.
Growth of Megacities
- In 1950, only New York and Tokyo had populations over 10 million
- By 2020, there were 34 megacities, with 28 in LICs and NEEs
- By 2030, the number is projected to reach 43, with most new megacities in Africa and Asia
- The largest megacity is Tokyo (37 million), followed by Delhi (32 million) and Shanghai (29 million)
Why Megacities Emerge in LICs and NEEs
- Rapid urbanisation: Millions migrating from rural areas each year
- Natural increase: High birth rates in young urban populations
- Economic growth: NEEs like China and India have industrialised rapidly, concentrating jobs in cities
- Globalisation: Foreign investment targets large cities for manufacturing and services
- Government policy: Some governments have promoted urban growth through investment and planning
| Megacity | Country | Population (millions) | Classification |
|---|---|---|---|
| Tokyo | Japan | 37 | HIC |
| Delhi | India | 32 | NEE |
| Shanghai | China | 29 | NEE |
| São Paulo | Brazil | 22 | NEE |
| Mexico City | Mexico | 22 | NEE |
| Cairo | Egypt | 21 | NEE |
| Mumbai | India | 21 | NEE |
| Dhaka | Bangladesh | 22 | LIC |
| Lagos | Nigeria | 15 | NEE |
Example: The Rise of Dhaka
Dhaka, the capital of Bangladesh, has grown from 1.5 million in 1970 to over 22 million today - one of the fastest-growing megacities in history. Its growth is driven by rural migrants fleeing flooding and poverty (push), attracted by garment industry jobs paying $100/month (pull). Natural increase adds to this rapid growth. However, the city struggles to provide basic services - over 3 million people live in slums, traffic congestion costs an estimated $4.4 billion per year, and water supply reaches only 60% of the population.
📊 Consequences of Rapid Urbanisation
- Slum growth: Over 1 billion people worldwide live in slums (informal settlements)
- Traffic congestion: Rapidly growing car ownership overwhelms infrastructure
- Pollution: Air, water and noise pollution from industry, traffic and waste
- Unemployment: Formal sector cannot create enough jobs for new arrivals
- Service shortage: Water, electricity, sanitation and healthcare cannot keep pace
- Housing crisis: Demand far exceeds supply; informal settlements proliferate
- Social inequality: Wealth gap between rich and poor is extreme in megacities
❓ Practice Questions
Q1: Define the term urbanisation. (2 marks)
Q2: Explain how push and pull factors contribute to rural-urban migration. (4 marks)
Q3: Why are most megacities now located in LICs and NEEs? (6 marks)
Q4: "Natural increase is a more significant cause of urban growth than migration." To what extent do you agree? (9 marks)
✅ Answers
- Urbanisation is the increase in the proportion of a country's population living in urban areas (towns and cities) rather than rural areas (1 mark). It is caused by rural-urban migration (people moving from countryside to city) and natural increase (births exceeding deaths within urban populations) (1 mark).
- Push factors drive people away from rural areas - low agricultural wages, lack of services (healthcare, education, electricity), drought and famine, and lack of employment opportunities (1 mark). For example, in many LICs, rural farmers earn less than $2 per day, pushing them to seek better incomes in cities (1 mark). Pull factors attract people to urban areas - better employment prospects in industry and services, higher wages, better healthcare and education, and access to services like electricity and clean water (1 mark). Migrants weigh up both sets of factors and decide that the benefits of city life outweigh the disadvantages of staying in rural areas (1 mark).
- Most megacities are now in LICs and NEEs because these countries are experiencing the most rapid urbanisation (1 mark). HICs are already highly urbanised (over 75%) and their urban growth has slowed, meaning their cities grow slowly if at all (1 mark). LICs and NEEs have high rates of rural-urban migration as people are pushed from the countryside by poverty and pulled to cities by job opportunities (1 mark). Natural increase is high in LIC/NEE cities because migrants are young adults with high birth rates, and improved urban healthcare has reduced death rates (1 mark). Economic growth in NEEs like China and India has concentrated industrial jobs in cities, attracting millions of workers (1 mark). Globalisation has directed foreign investment to large cities in NEEs, creating employment that fuels further urban growth (1 mark).
- I agree that natural increase is very significant, accounting for approximately 60% of urban population growth in LICs and NEEs (1 mark). This is because migrants are predominantly young adults of childbearing age, leading to high urban birth rates (1 mark). Improved healthcare in cities reduces death rates, widening the gap between births and deaths and increasing natural growth (1 mark). In Lagos, natural increase alone adds 2.6% to the population annually (1 mark). However, migration is also a crucial driver, accounting for about 40% of urban growth (1 mark). Without migration, cities would not have the young populations that generate high natural increase - migration and natural increase are interlinked (1 mark). In some cities, migration is the dominant cause - Dhaka's explosive growth from 1.5 million to 22 million was initially driven by mass rural-urban migration (1 mark). Migration also contributes indirectly to natural increase by bringing young adults to cities (1 mark). The relative importance varies between cities and over time - migration may dominate during early urbanisation, while natural increase becomes more significant once a large urban population is established (1 mark). In conclusion, while natural increase contributes more to overall urban growth numerically, migration is the catalyst that creates the conditions for natural increase, making both essential and interdependent causes of urban growth (1 mark).
🎯 Exam Tips
- Always define urbanisation before discussing its causes or impacts
- Use specific facts and statistics for megacities (population, growth rates)
- For push-pull questions, give equal attention to both sets of factors
- Know the difference between migration and natural increase as causes of urban growth
- Explain that natural increase and migration are INTERLINKED, not separate
- Use LIC/NEE examples for megacities - examiners expect Dhaka, Lagos, Mumbai
📝 Exam Technique
Geography Exam Tips — Urbanisation and Megacities:
1. For Urbanisation and Megacities questions, always name specific case studies with factual detail
2. Use geographical terminology precisely (e.g. specific processes, not vague descriptions)
3. Consider social, economic and environmental perspectives in your evaluations
4. Support your points about Urbanisation and Megacities with data, statistics or named examples
5. For 'assess' or 'evaluate' questions, reach a clear judgement supported by evidence
1. For Urbanisation and Megacities questions, always name specific case studies with factual detail
2. Use geographical terminology precisely (e.g. specific processes, not vague descriptions)
3. Consider social, economic and environmental perspectives in your evaluations
4. Support your points about Urbanisation and Megacities with data, statistics or named examples
5. For 'assess' or 'evaluate' questions, reach a clear judgement supported by evidence
⚠️ Common Errors
Watch Out!
Students often write vague answers without specific geographical evidence. Wrong: Writing generalised statements like 'it causes problems' Correct: Using specific data and named examples, e.g. 'the 2010 Haiti earthquake killed over 200,000 people due to poor building quality'
Students often confuse causes and effects. Wrong: Mixing up what caused the event with what resulted from it Correct: Clearly separate causes (why it happened) from effects (what happened as a result)
Students often describe rather than evaluate. Wrong: Listing strategies without assessing their effectiveness Correct: Weighing up strengths and weaknesses of each approach and reaching a supported judgement
✍️ Model Answer
Full-Mark Response
6 marks: Explain the key factors affecting urbanisation and megacities.
Urbanisation and Megacities involves multiple interconnected factors that geographers must understand. The key concepts include the processes that create and change urbanisation and megacities, the impacts on both people and environment, and the strategies used to manage associated challenges. For a comprehensive answer, specific case study evidence should be used throughout, with named examples and data to support each point. Geographical terminology should be used precisely, and the interrelationship between physical and human factors should be demonstrated. Top-level responses evaluate the relative importance of different factors and consider how the situation varies between locations.
Mark scheme: 2 marks for identifying key factors, 2 marks for explaining processes with detail, 2 marks for using specific evidence
📊 AO Deep Dive
Assessment Objective Analysis
AO1 requires knowledge of the key facts and processes related to urbanisation and megacities. AO2 demands understanding of how and why these processes operate, and their implications. AO3 asks you to analyse, evaluate and make judgements — this is where grade 9 answers stand out by weighing up competing perspectives and reaching supported conclusions. AO4 may involve interpreting maps, graphs or data related to this topic. To move from grade 5 to grade 9: use precise geographical terminology, support every point with specific case study evidence, and always evaluate rather than just describe.
📝 Exam Questions by Topic
🎬 Video Resources
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