Rate & Rise of Megacities (Edexcel IGCSE Geography): Revision Note

Rate of urbanisation

Factors affecting the rate of urbanisation

• The main factors affecting the rate of urbanisation are the:

  • Speed of economic development

  • Rate of population growth

• Speed of economic development

  • Economic growth drives urbanisation

  • The faster the growth of secondary and tertiary employment sectors, the faster the growth of urbanisation

• Rate of population growth

  • Economic growth needs a supply of labour

  • This demand can be met in two ways:

    • Natural increase in urban population is a slow way of meeting demand

    • Rural-urban migration - this is the more important source of labour as it attracts a wider pool of people into the urban region

Rise of megacities

• Megacities are urban regions with over 10 million residents   

• In 2007, more people lived in an urban environment than a rural one

• By 2050 it is thought that more than two-thirds (7 billion) of the world's population will live in urban areas

• This scaling up of the urban environment is the fastest in human history

• The largest growth of megacities is seen in Asia

Reasons for growth

• The four main factors for the growth of megacities are:

  • Economic development

  • Population growth

  • Economies of scale

  • Multiplier effect

Economic development

• Encourages population growth, which leads to the desirability of goods and services

• All megacities act as service centres within the formal economic sector

• However, megacities in developing and emerging countries are also important manufacturing centres (Mumbai in India or Dhaka in Bangladesh) with thousands working in the informal economy

Population growth

• Young people are drawn to live in megacities with their vibrancy, fast pace and opportunities

• There is also ‘internal growth’ where people who have moved into the cities have children, so sustaining population growth (Mexico City, Mumbai, Pearl River Delta in China)

Economies of scale

• It is cheaper to provide goods and services in one place than spread across several cities

• Financial savings for local governments in respect of infrastructure provision

• Communication and transport are centralised, making savings in time and money

Multiplier effect

• As a city prospers, it acts as a beacon to people and businesses 

• This encourages inward investment

• This leads to yet more development and growth

• Generating further need for skills and labour and job growth

• This cycle multiplies the positive effects and growth continues (San Francisco and the digital development)

World cities

• Megacities have a powerful attraction for people and businesses 

• They are influential cores with large peripheries

• World or global cities can be any size but exert particular influences around the globe, they are:

  • considered prestigious, with status and power  

  • critical hubs in the global economy

• The three top (alpha) world cities are:

  • London

  • New York

  • Tokyo 

• These are the financial centres of the world, each with smaller networks of world cities feeding into them

• There are only four world cities in the Southern Hemisphere:  

  • Sydney

  • Rio de Janeiro

  • Sao Paulo

  • Buenos Aires