Population Dynamics » Population density and patterns

What you'll learn this session

Study time: 30 minutes

How population density is calculated and measured
The difference between population density and distribution
Global patterns of population density
Physical factors affecting population distribution
Human factors affecting population distribution
Case studies of densely and sparsely populated areas

Population Density and Distribution

People aren't spread evenly across the Earth. Some places are packed with people while others are almost empty. Understanding why people live where they do is a key part of geography!

Key Definitions:

Population density: The average number of people living in a given area, usually expressed as people per square kilometre.
Population distribution: The pattern of where people live across an area.
Sparsely populated: Areas with few people living in them.
Densely populated: Areas with many people living in them.

Measuring Population Density

Population density is calculated using a simple formula:

Population Density Formula

Population Density = Total Population ÷ Total Land Area

Example: If a country has 10 million people and an area of 100,000 km², its population density is 100 people per km².

However, this simple calculation has limitations. It gives us the arithmetic density, which doesn't account for:

Uninhabitable land (deserts, mountains, etc.)
How people cluster in cities
Seasonal population changes

Global Population Patterns

Looking at a world population density map, we can see clear patterns:

🌎 High Density Areas

Population clusters:

East Asia (China, Japan)
South Asia (India, Bangladesh)
Western Europe
Northeast USA
Southeast Brazil
Nile Valley

🏜 Low Density Areas

Population voids:

Deserts (Sahara, Gobi, Australian Outback)
Polar regions (Antarctica, Arctic)
High mountains (Himalayas, Andes)
Dense forests (Amazon, Congo)
Extreme environments (Siberia, Canadian North)

Factors Affecting Population Distribution

Why do people live where they do? The answer involves both physical (natural) and human factors.

Physical Factors

⛰ Relief & Landscape

Flat, lowland areas are easier to build on and farm than steep, mountainous regions. The North European Plain is densely populated, while the Alps are much less so.

🌞 Climate

Moderate climates attract more people than extreme ones. Few people live in the Sahara Desert or Antarctica due to temperature extremes and lack of water.

🌱 Soil & Vegetation

Fertile soils support agriculture and therefore larger populations. The Nile Valley has supported dense populations for thousands of years thanks to its rich soil.

💧 Water Supply

Access to fresh water is essential for life. Most major cities are located near rivers, lakes, or coastlines. The Ganges River basin supports hundreds of millions of people.

⚡ Natural Resources

Areas rich in minerals, fossil fuels, or other resources often attract populations. The discovery of oil in the UAE transformed sparsely populated desert into urban centres.

🌋 Natural Hazards

Areas prone to frequent disasters may have lower populations. However, fertile volcanic soils or other benefits sometimes outweigh the risks (e.g., Java, Indonesia).

Human Factors

🏛 Economic Opportunities

People move to where jobs are available. Urban areas and industrial regions typically have higher population densities than rural areas.

🚗 Transport Links

Good transport connections (roads, railways, ports) make areas more accessible and attractive for settlement. Major transport hubs often become population centres.

🏫 Social Amenities

Access to healthcare, education and entertainment attracts people. Cities offer more services than rural areas, contributing to urbanisation.

🗣 Political Factors

Government policies can encourage or discourage settlement in certain areas. China's hukou system has historically controlled internal migration, while Singapore's public housing policy has shaped its population distribution.

👥 Historical Settlement

Past patterns of settlement influence present ones. Many European cities were founded by Romans or grew around medieval castles and still remain population centres today.

Population Density Case Studies

Case Study: Bangladesh - High Density

Population density: Approximately 1,265 people per km² (one of the highest in the world)

Why so dense?

Physical factors: Fertile alluvial soil from the Ganges-Brahmaputra delta, flat terrain suitable for farming and settlement, abundant water supply
Human factors: Agricultural economy requiring intensive labour, historical settlement patterns, limited emigration opportunities

Challenges: Limited land resources, vulnerability to flooding and climate change, pressure on services and infrastructure

Case Study: Australia - Low Density

Population density: Approximately 3 people per km² (one of the lowest among developed nations)

Why so sparse?

Physical factors: Large desert interior (the Outback) with extreme temperatures and limited water, poor soils in many areas
Human factors: Relatively recent European settlement, highly urbanised population concentrated in coastal cities

Pattern: Over 85% of Australians live within 50km of the coast, creating a "hollow" population distribution

Changing Population Patterns

Population patterns aren't fixed - they change over time due to:

Urbanisation: The global trend of people moving from rural to urban areas
Technology: Allowing people to live and work in previously inhospitable environments
Climate change: Potentially making some areas uninhabitable while opening others for settlement
Economic shifts: As industries rise and fall, population centres can shift

Population Density and Sustainability

Different population densities create different challenges and opportunities:

🏙 High Density Areas

Advantages:

Efficient use of land and resources
Lower per-person carbon footprints
Easier provision of services

Challenges:

Congestion and pollution
Housing shortages
Pressure on infrastructure

🌲 Low Density Areas

Advantages:

Less crowding and pollution
More space per person
Often closer connection to nature

Challenges:

Higher per-person resource use
Expensive service provision
Dependence on transport

Summary: Why Population Patterns Matter

Understanding population density and distribution helps us:

Plan for future development and resource needs
Prepare for natural disasters and emergencies
Develop sustainable cities and communities
Understand human-environment interactions
Make sense of economic and social patterns

Next time you look at a map or travel to a new place, think about why people live where they do. Is it because of the physical environment, human factors, or a combination of both?