The concept of urbanisation and global urban population trends

Urbanisation refers to the process where towns and cities expand and develop as their populations increase.

Key trends in global urbanisation

• Current urban population - According to estimates, 55% of the world's population lived in urban areas in 2018.
• Daily increase - The number of people living in cities grows by approximately 180,000 each day.
• Future projections - By 2050, it is predicted that around 75% of the global population will reside in towns and cities.

The classification of cities, megacities, and world cities

Urban settlements vary in size, function, and global importance. They can be categorised into different types based on population, roles, and economic influence, forming a hierarchy of human settlements.

The settlement hierarchy

Settlements range from small, isolated dwellings to vast urban conglomerates. As population grows, settlements evolve, gaining more functions and services.

City status and functions:

• In the UK, a town gains city status through a royal grant by the monarch, not automatically by population size.
• The designation can also depend on the settlement's role locally, nationally, or globally.
• Cities often serve administrative roles or act as hubs for specific activities.

Megacities

A megacity is typically defined as a city with over 10 million inhabitants, though definitions can vary slightly. These are often capital cities experiencing rapid population growth.

World cities

World cities hold significant influence in the global economic system, often marked by iconic status and landmarks. They play pivotal roles in international affairs and commerce.

Characteristics of world cities:

• Economic hubs - Host headquarters of multinational companies, major banks, or stock exchanges.
• Innovation centres - Drive advancements in business, media, and communications.
• Global integration - Deeply connected to the global economy with important port facilities and manufacturing bases.
• Cultural significance - Offer diverse cultural opportunities such as live music, cinema, and opera.
• Educational excellence - Home to highly rated universities, often focusing on cutting-edge research.

The distribution and growth of megacities worldwide

The number of megacities has risen dramatically over recent decades due to rapid urbanisation, particularly in certain regions of the world. These urban giants house significant populations but represent a small fraction of the global total.

Trends in megacity distribution

• Historical growth - In the 1950s, only two megacities existed globally. Today, there are over 30 such cities.
• Population size - Some megacities now exceed 20 million residents.
• Global share - Despite their large individual populations, megacities collectively account for just 5% of the world's population.

Urban growth rates across different country categories

Urban growth patterns differ significantly based on a country's economic development status. These variations are evident when comparing advanced countries (ACs), emerging and developing countries (EDCs), and low-income developing countries (LIDCs).

Urban growth in advanced countries (ACs)

• Peak growth period - Cities in regions like Europe and North America saw their highest growth rates before or during the 1950s.
• Sustained growth - The most sustained period of growth took place during the Industrial Revolution in the late 1700s to 1800s.
• Post-war expansion - After the Second World War, a population surge known as the 'baby boom' and extensive housing development led to urban sprawl.
• Early urban giants - Cities like London and Paris were among the first to reach a population of 1 million, termed 'millionaire cities'.
• Current urbanisation level - Most ACs now have over 70% of their populations living in urban areas.

Urban growth in emerging and developing countries (EDCs) and low-income developing countries (LIDCs)

• Recent surge - Cities in Asia and Africa have surpassed the earlier urban growth seen in Europe and North America.
• Driving factors - Economic opportunities in urban areas fuel rural-to-urban migration, causing younger individuals to move to cities for employment.
• Natural increase - Migrants often start families in urban settings, contributing to high natural population growth rates.
• Massive migration - Nearly 200 million people relocated to urban areas between 2000 and 2010.
• Rapid growth examples - Cities like Dhaka (7% annual growth), Lagos (5.6%), and Delhi (4.6%) are experiencing some of the fastest urban expansion rates globally.