Factors affecting global population distribution

Population distribution describes the pattern of where people live across the world. Several physical and environmental factors play a significant role in determining these patterns, influencing where populations cluster or remain sparse.

Key physical factors shaping population distribution

• Proximity to the sea - Around three-quarters of the global population reside within 1,000 km of coastal areas.
• Low-lying terrain - Nearly 90% of people live in regions below 500 m in elevation, as flat, low ground is easier for settlement, agriculture, and infrastructure development.
• Northern hemisphere dominance - Over 80% of the world's population is located in the northern hemisphere.
• Fertile river valleys - Areas near rivers with rich, arable soil support large populations through agriculture.
• Reliable water supply - Places with consistent access to water are more attractive for settlement.
• Climate variability - There is no single "ideal" climate for settlement; densely populated regions like South East Asia experience monsoonal climates with alternating wet and dry seasons, showing adaptability to diverse conditions.

Key areas of high and low population density worldwide

Population density varies significantly across the globe, with certain regions supporting large concentrations of people while others remain sparsely inhabited due to challenging conditions.

Regions with high population density

• South East Asia - A major hub with densities exceeding 200 people per km².
• North-east USA - High density due to urbanisation and industrial development.
• Western Europe - Densely populated with over 200 people per km² in many areas.
• Smaller high-density zones - Include south-east Brazil, the Mexican plateau, the Nile Valley in Egypt, California in the USA, and the island of Java in Indonesia.

Regions with low population density

Areas that are too dry (like deserts), too steep (mountainous regions), too cold (polar areas), or infertile (barren soils) are generally avoided for settlement. Vast deserts like the Sahara, high mountain ranges like the Himalayas, and polar regions like Antarctica have densities often below 6 people per km².

Urban population concentrations

• Megacities - Cities with over 10 million inhabitants, such as Tokyo, Shanghai, and Delhi, represent significant urban density.
• Large urban centres - Cities with populations between 5 and 10 million, like São Paulo and Bangkok, also contribute to high-density clusters.
• Smaller urban hubs - Cities with 1 to 5 million people, such as San Francisco and Cairo, form important regional population centres.

Human influences on population distribution

Beyond physical factors, human decisions and activities significantly shape where populations are located, often overriding environmental constraints through policy, conflict, and economic drivers.

Human factors impacting population patterns

• Resource distribution - The availability of raw materials, such as coal and minerals, has historically led to population clusters in industrial areas of countries like the USA, China, India, Germany, and the UK.
• Government policies - Policies can redistribute populations, for instance through forced relocations under historical systems like Apartheid in South Africa or more recent actions affecting groups like the Rohingya in Myanmar.
• New town developments - Planned urban areas in places like Egypt, Hong Kong, and the UK aim to redistribute populations away from overcrowded regions.
• Conflict and war - Armed conflicts can depopulate areas, as seen in regions like Syria and northern Nigeria, where people flee due to violence.
• Migration patterns - Both voluntary and forced migration reshapes population distribution, such as the movement of African migrants to South Africa.

Using Lorenz curves to show population distribution inequalities

Lorenz curves are graphical tools used to illustrate inequalities in the distribution of population across a given area, highlighting how concentrated or evenly spread people are within a region or country.

Understanding Lorenz curves

Key components of Lorenz curves:

• Axes of the curve - The horizontal axis represents the percentage of the total area, while the vertical axis shows the percentage of the population, both ranging from 0 to 100.
• Line of perfect equality - A straight diagonal line from (0,0) to (100,100) indicates a perfectly even distribution.
• Curve of concentration - Actual distribution is shown by a curve below the equality line, bending towards the bottom-right, indicating inequality where a small percentage of land holds a large percentage of the population.
• Shaded area of inequality - The space between the equality line and the curve represents the degree of inequality in population distribution.

Comparative examples:

• Curves for different countries show varying levels of concentration.
• Egypt demonstrates extreme inequality with 95% of its population living on just 5% of its land.
• Countries like the UK show less disparity compared to the USA.

Interpreting Lorenz curves

• Greater curve deviation - A curve that bends more sharply away from the equality line indicates higher inequality, meaning the population is more concentrated in specific areas.
• Application to policy - Understanding these curves helps in planning resource allocation and addressing overcrowding or underpopulation in specific regions.