Explain the causes of urbanisation and the growth of megacities, analyse the consequences for people and environments, and evaluate strategies that manage urban growth sustainably.

What this dot point is asking

This dot point sits within Topic 3, Population Change. It links population movement to the places people move into. Strong answers connect the causes of urbanisation to specific consequences and judge how well cities are managing growth.

Causes of urbanisation

For the first time in history, more than half the world's people live in cities, and the United Nations projects this will rise to roughly two-thirds by 2050. The drivers are:

• Rural-to-urban migration, pulled by jobs, education, services and the perception of opportunity, and pushed by rural poverty, drought and mechanised agriculture.
• Natural increase within cities, as young migrant populations have children.
• Economic change, as manufacturing and services concentrate in cities.

Urbanisation is fastest in Asia and Africa. Cities such as Lagos in Nigeria and Dhaka in Bangladesh are among the world's fastest-growing, while Tokyo remains the largest urban agglomeration with over 37 million people.

Consequences for people and environments

Urbanisation brings opportunity but also strain.

• Housing: rapid growth outpaces formal housing, producing informal settlements. Over a billion people live in slums worldwide, such as Dharavi in Mumbai, often lacking secure tenure, clean water and sanitation.
• Services and infrastructure: traffic congestion, overloaded transport, water shortages and waste management problems are common in fast-growing cities.
• Environment: cities concentrate pollution, create urban heat islands, and expand onto farmland and habitat. Air pollution in megacities such as Delhi reaches hazardous levels.

In Australia, urbanisation takes a different form: the country is already highly urbanised, with most people in a few coastal capitals. The challenge is urban sprawl on the fringes of Melbourne and Sydney and pressure on housing affordability.

Consequences across systems

Economically, cities are engines of growth and innovation, generating most of the world's GDP, but inequality within cities can be stark. Socially, cities offer services and diversity but can isolate the poor in under-serviced settlements. Environmentally, dense cities can be efficient per person, yet sprawling, car-dependent cities consume land, water and energy heavily.

Strategies for managing urban growth

Management aims to make cities more sustainable and liveable.

• Planning and growth boundaries to limit sprawl and protect farmland and green space, as used around Melbourne.
• Transit-oriented development and public transport to reduce car dependence and congestion.
• Upgrading informal settlements with water, sanitation and secure tenure rather than demolishing them.
• Green infrastructure such as parks, street trees and cool roofs to reduce the urban heat island.
• Building affordable and higher-density housing near jobs and transport.

Evaluation means weighing trade-offs: growth boundaries protect bushland but can push up land prices, while higher density eases sprawl but needs community support and good design.

Linking it together

A complete response explains the push and pull causes of urbanisation, analyses consequences for housing, services, infrastructure and the environment, contrasts fast-growing megacities such as Lagos and Dhaka with already-urbanised Australia, and evaluates management strategies. That structure matches the geographical skills and applications criteria the SACE Board assesses.