Factors affecting the rate of urbanisation

Urbanisation refers to the increasing proportion of a population living in urban areas, often driven by economic and demographic changes. The speed at which urbanisation occurs varies across regions and is influenced by specific factors that shape the movement of people from rural to urban environments.

Main drivers of urbanisation rates

• Economic development - The pace of economic growth drives urbanisation; when the growth of the secondary and tertiary sectors is fast, so is the pace of urbanisation.
• Population growth - Economic growth needs an increasing supply of labour. The demand for more workers can be met through natural increase in the urban population or by rural-urban migration. Rural-urban migration is usually the more important source of labour, as people are attracted by urban job opportunities, services, and the perception of a better urban lifestyle.
• Multiplier effect - Economic growth encourages population growth. Population growth, in turn, makes more labour available and creates a need for more services, leading to further economic growth in a self-reinforcing cycle.

The growth and distribution of megacities

The scale and number of large urban areas have expanded dramatically over recent decades, reflecting global trends in urbanisation. Megacities, defined as cities with populations exceeding 10 million, have become prominent features of the modern world, alongside other categories of large cities.

Evolution of large urban centres

• Historical shift in city size - In 1900, only a handful of cities, such as London and Paris, had populations over one million, known as millionaire cities. By 2020, this number had surged to around 500 worldwide.
• Rise of five-million cities - The number of cities with over five million residents has grown from around 8 in 1950 to over 50 today.
• Megacity expansion - In 1970, there were only four megacities globally. This figure has now risen to 35, with over half located in Asia.

Distribution patterns of large cities

Fifty years ago, half of the world's ten largest cities were in developed countries. By the year 2000, only two of the 10 were in the developed world.

Key reasons behind the development of megacities

The emergence of megacities is not random but is driven by a combination of economic, demographic, and structural factors. These elements create conditions that support massive urban growth and sustain the concentration of populations in specific areas.

Factors promoting megacity growth

• Economic development - Economic growth drives urbanisation.
• Population growth and migration - Young people are drawn to live in these megacities by the 'buzz' of feeling close to 'where it is all happening', with a sense of prestige and 'street cred' associated with living and working in such 'cool' places.
• Economies of scale - There are advantages from cramming as much as possible into one megacity rather than into a number of smaller cities. Since distances within a megacity are less than between smaller cities, there are financial savings in terms of transport. Communication between people and businesses will also be easier.
• Multiplier effect - Once a large city is prospering, it gathers a momentum which will carry it forward. This leads to yet more prosperity and growth, as more jobs attract more people, who in turn need more goods and services, creating more jobs and continuing the cycle.

Challenges associated with megacities

• Intensified urban issues - All common urban problems are present in megacities and are often even more acute.
• National imbalance - Megacities grow and prosper at the expense of towns, cities, and regions elsewhere within the country, becoming powerful cores that create large peripheries around them.

The concept and significance of global or world cities

Beyond sheer population size, some cities hold exceptional importance due to their influence on the global stage. These are known as global or world cities, which play critical roles in the international economy and culture, regardless of their population.

Characteristics of global or world cities

Global or world cities can be of any size. At present, there are 31 such cities, all with populations over 1 million, and seven of them are also megacities (Buenos Aires, Hong Kong, Mexico City, New York, Rio de Janeiro, São Paulo, Seoul).

Key examples:

• The three most important global cities are London, New York, and Tokyo, serving as the financial centres of the global economy, which is why they have power and influence.

Network connections:

• Each of these three cities is the hub of a network of smaller global cities.
• Four global cities are located outside these three networks – Rio de Janeiro, São Paulo, Buenos Aires, and Sydney – and are all in the southern hemisphere.

Global cities are recognised worldwide as places of great prestige, status, power, and influence, and are critical hubs in the growing global economy.