# Population density

Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.[1] In simple terms, population density refers to the number of people living in an area per square kilometre, or other unit of land area.

Population density (people per km2) by country or U.S. state in 2019
Population density (people per km2) map of the world in 1994. In relation to the equator it is seen that the vast majority of human population lives in the Northern Hemisphere, as 67% of Earth's land area is there.

## Biological population densities

Population density is population divided by total land area, sometimes including seas and oceans, as appropriate.[1]

Low densities may cause an extinction vortex and further reduce fertility. This is called the Allee effect after the scientist who identified it. Examples of the causes of reduced fertility in low population densities are:[2]

• Increased problems with locating sexual mates
• Increased inbreeding

### Human densities

Population density (people per km2) by country, 2006

Population density (people per km2) map of the world in 2005

Population density is the number of people per unit of area, usually transcribed as "per square kilometer" or square mile, and which may include or exclude, for example, areas of water or glaciers. Commonly this is calculated for a county, city, country, another territory or the entire world.

The world's population is around 8,000,000,000[3] and the Earth's total area (including land and water) is 510,000,000 km2 (197,000,000 sq. mi.).[4] Therefore, from this very crude type of calculation, the worldwide human population density is approximately 8,000,000,000 ÷ 510,000,000 = 16/km2 (41 per sq. mi.). However, if only the Earth's land area of 150,000,000 km2 (58,000,000 sq. mi.) is taken into account, then human population density is 53/km2 (138 per sq. mi.). This includes all continental and island land area, including Antarctica. However, if Antarctica is excluded, then population density rises to over 58 persons/km2 (154 per sq. mi.).[1]

World environments map provided for comparison with maps above

The European Commission’s Joint Research Centre (JRC) has developed a suite of (open and free) data and tools named the Global Human Settlement Layer (GHSL) to improve the science for policy support to the European Commission Directorate Generals and Services and as support to the United Nations system.[5]

Several of the most densely populated territories in the world are city-states, microstates and urban dependencies.[6][7] In fact, 95% of the world's population is concentrated on just 10% of the world's land.[8] These territories have a relatively small area and a high urbanization level, with an economically specialized city population drawing also on rural resources outside the area, illustrating the difference between high population density and overpopulation.

Deserts have very limited potential for growing crops as there is not enough rain to support them. Thus, their population density is generally low. However, some cities in the Middle East, such as Dubai, have been increasing in population and infrastructure growth at a fast pace.[9]

Mongolian Steppes. Mongolia is the least densely populated country in the world due to its harsh climate as a result of its geography.[10]

Cities with high population densities are, by some, considered to be overpopulated, though this will depend on factors like quality of housing and infrastructure and access to resources.[11] Very densely populated cities are mostly in Asia (particularly Southeast Asia); Africa's Lagos, Kinshasa, and Cairo; South America's Bogotá, Lima, and São Paulo; and Mexico City and Saint Petersburg also fall into this category.[12]

Monaco is currently the most densely populated nation in Europe.

City population and especially area are, however, heavily dependent on the definition of "urban area" used: densities are almost invariably higher for the center only than when suburban settlements and intervening rural areas are included, as in the agglomeration or metropolitan area (the latter sometimes including neighboring cities).

In comparison, based on a world population of 7.8 billion, the world's inhabitants, if conceptualized as a loose crowd occupying just under 1 m2 (10 sq. ft) per person (cf. Jacobs Method), would occupy a space a little larger than Delaware's land area.[citation needed]

### Countries and dependent territories

Population under 10,000,000
Rank Country or
dependent territory
Land Area Population Density
km2 sq. mi. per km2 per sq.
mi.
1   Macau (China) 30.5 12 650,834 21,339 55,268
2   Monaco 2.02 0.78 37,550 18,589 48,145
3   Singapore 719.9 278 5,612,300 7,796 20,192
4   Hong Kong (China) 1,106.3 427 7,409,800 6,698 17,348
5   Gibraltar (UK)[13] 6.8 2.6 33,140 4,874 12,624
6   Bahrain 757 292 1,451,200 1,917 4,965
7    Vatican City 0.44 0.17 800 1,818 4,709
8   Malta 315 122 475,701 1,510 3,911
9   Maldives 298 115 378,114 1,269 3,287
10   Bermuda (UK) 52 20 63,779 1,227 3,178
Population above 10,000,000
Rank Country Land Area Population Density
km2 sq. mi. per km2 per sq.
mi.
1   Bangladesh 134,208 51,818 170,329,768 1,269 3,287
2   Taiwan 32,260 12,456 23,539,588 730 1,891
3   Rwanda 24,668 9,524 13,246,394 537 1,391
4   Netherlands 33,670 13,000 17,821,419[14] 529 1,370
5   South Korea 99,909 38,575 51,439,038 515 1,334
6   Burundi 25,680 9,915 12,574,571 490 1,269
7   India 2,973,190 1,147,955 1,374,547,140 462 1,197
8   Haiti 27,560 10,641 11,743,017 426 1,103
9   Belgium 30,278 11,690 11,554,449 382 989
10   Philippines 298,170 115,124 109,961,895 369 956

### Other methods of measurement

This population cartogram of the European Union (2007–2012) uses areas and colors to represent population.

Living population density by country

Although the arithmetic density is the most common way of measuring population density, several other methods have been developed to provide alternative measures of population density over a specific area.

• Arithmetic density: The total number of people / area of land
• Physiological density: The total population / area of arable land
• Agricultural density: The total rural population / area of arable land
• Residential density: The number of people living in an urban area / area of residential land
• Urban density: The number of people inhabiting an urban area / total area of urban land
• Ecological optimum: The density of population that can be supported by the natural resources
• Living density: Population density at which the average person lives[15]

## References

1. ^ a b c Matt Rosenberg Population Density. Geography.about.com. March 2, 2011. Retrieved on December 10, 2011.
2. ^ Minimum viable population size. Archived October 6, 2012, at the Wayback Machine Eoearth.org (March 6, 2010). Retrieved on December 10, 2011.
3. ^ U.S. & World Population Clocks. Census.gov. Retrieved on November 19, 2022.
4. ^ World. CIA World Factbook
5. ^ "The global human settlement layer sets a new standard for global urban data reporting with the urban centre database". frontiersin.org. September 15, 2022. Retrieved May 17, 2023.
6. ^ Department of Economic and Social Affairs Population Division (2009). "World Population Prospects, Table A.1" (PDF). 2008 revision. United Nations. Retrieved March 12, 2009.
7. ^ The Monaco government uses a smaller surface area figure resulting in a population density of 18,078 per km2
8. ^ "Urbanization: 95% Of The World's Population Lives On 10% Of The Land". ScienceDaily. Retrieved September 1, 2020.
9. ^ Portnov, B. A.; Hare, A. Paul (1999). Desert regions : population, migration, and environment. Springer. ISBN 3540657800. OCLC 41320143.
10. ^ "Why Mongolia is sparsely populated?". Esther Fleming. SidmartinBio.
11. ^ Human Population. Global Issues. Retrieved on December 10, 2011.
12. ^ The largest cities in the world by land area, population and density Archived May 16, 2015, at the Wayback Machine. Citymayors.com. Retrieved on December 10, 2011.
13. ^ Territory claimed by Spain.
14. ^ Centraal Bureau voor de Statistiek (CBS) (January 2023). "Population counter". Centraal Bureau voor de Statistiek. Retrieved March 30, 2023.
15. ^ Analysis of living population density per countries, based on NASA SEDAC world gridded data.