People are unevenly distributed around the world. The difference in distribution is measured by comparing population density – the number of people per square kilometre (km²).
Population density is determined more by environmental factors which make an area more or less attractive to settlers than by economic development.
The way in which people are spread across a given area is known as population distribution. Geographers study population distribution patterns at different scales: local, regional, national, and global.
Patterns of population distribution tend to be uneven. For example, in the UK there are more people living in south-east England than in Wales.
Population density is the average number of people per square kilometre. It is a way of measuring population distribution and shows whether an area is sparsely or densely populated. Population density is calculated using the following formula:
Population density = total population ÷ total land area in km²
The map shows patterns of population density on a global scale.
- Areas of high and low population density are unevenly spread across the world
- The majority of places with high population densities are found in the northern hemisphere
Map of the world showing population density
The population density of a country is has very little to do with its level of economic development. For example, both Bangladesh and Japan are very densely populated, but Bangladesh is a LEDC and Japan is a MEDC.
Factors affecting population density
Environmental and human factors affect the spread of people across the world.
Factors attracting settlement
- Temperate climate, eg the UK
- Low-lying flat fertile land, eg the Bangladesh Delta
- Good supplies of natural resources, eg building resources
Factors discouraging settlement
- Extreme climates, eg Sahara Desert
- Mountainous or highland areas, eg the Scottish Highlands
- Dense vegetation, eg the Amazon Rainforest
Factors such as the availability of jobs and comparatively high wages can contribute to high population density through migration. For example, from 2004 the UK has seen an influx of migrants from countries that have recently joined the EU, such as Poland.
Civil war, eg in the Darfur region of Sudan, can contribute to lower population densities as people become refugees and leave an area.