Population distribution

Topic: World Population: Distribution, Density, Growth and Migration · NCERT: Class 12, Ch 2 "The World Population: Distribution, Density and Growth"

Meaning

Population distribution is the way people are spread over the earth's surface. It tells us where people live. It matters because people are a country's real wealth: they use its resources and make its policies. Their very uneven spread decides where land, water and cities come under pressure.

Explanation

What distribution shows, and how it differs from density

• Distribution answers "where?" It shows which places are crowded and which are almost empty.
• Density answers "how many on each piece of land?"
• Formula: Density = Population ÷ Area. It is shown as persons per sq km.

• NCERT example: 1,50,000 people on 100 sq km → 1,50,000 ÷ 100 = 1,500 persons per sq km.

• The two go together. A map of distribution shows the pattern, and density figures measure it.

• Density shows pressure on land. High density means more demand for food, water, housing and jobs from the same piece of land.

A very uneven pattern

• About 90 per cent of the world's people live on about 10 per cent of its land (NCERT).

• So most of the earth's land holds very few people.

• People are packed into a few countries:

• The 10 most populous countries hold about 60 per cent of world population (NCERT).

• Six of these 10 are in Asia (NCERT): India, China, Indonesia, Pakistan, Bangladesh and Russia. Russia is counted as Asian because most of its land lies in Asia.

• George B. Cressey wrote about Asia: "Asia has many places where people are few and few places where people are very many."

• Many empty places: the Gobi and Thar deserts, the Tibetan plateau, Siberia and the Himalaya.
• A few very crowded places: the Ganga plains, eastern China and Java.
• The same pattern holds for the whole world.

Why people gather in some places and avoid others

• Physical factors explain the empty areas.
• Too cold: polar lands have frozen ground and a very short growing season.
• Too dry: hot deserts have little water and great heat. Cold deserts are dry and have very cold winters.
• Too wet and thickly forested: equatorial forests have heavy rain, thick forest, soil that turns poor once the forest is cleared, and disease.

• Too high and steep: high mountains have steep slopes, cold and thin air, and little flat land.

• Economic and historical factors explain the crowded areas.

• Fertile river plains and deltas: deep alluvial soil (fine, fertile soil laid down by rivers) supports dense farming. A delta is the flat, fertile land where a river meets the sea.
• Monsoon rice lands: monsoon rain and wet rice farming can feed many people on small plots.
• Volcanic soil: Java's volcanic soil is very fertile.
• Industrial belts: industry, ports, big cities and good transport draw people.
• Long settlement: places such as eastern China have been farmed for a very long time.

Arithmetic density and physiological density

• Arithmetic density = total population ÷ total land area. This is the normal "density" figure.
• Physiological density = total population ÷ cultivable (farmable) land. It shows the pressure on the land that can actually grow food.
• Why we need both: a country with large deserts looks thinly peopled on arithmetic density, but its farmland may be very crowded.
• Egypt is the classic case:
• Only about 4 per cent of Egypt's land is suitable for farming [4].
• About 95 per cent of Egyptians live in towns and cities on the Nile floodplain [4].
• Its population grew from 45 million in the 1980s to more than 100 million (2021) [4].
• Result: Egypt's arithmetic density is moderate, but its physiological density is very high.

Where it occurs

Dense areas of the world

• East Asia: eastern China, Japan and Korea, on the Pacific coast at about 20°N–45°N. These have the fertile plains of the Huang He and Chang Jiang.
• South Asia: the Ganga-Brahmaputra plains, the Indus plains and the Kerala coast, in India, Bangladesh and Pakistan.
• Southeast Asia: Java (Indonesia, about 7°S), the Mekong delta (south Vietnam, on the South China Sea) and the Irrawaddy delta (Myanmar, on the Andaman Sea).
• Europe: north-western and western Europe, including Britain, Germany, Benelux and northern Italy.
• North America: north-eastern USA, from Boston to Washington plus the Great Lakes.
• Africa: the Nile valley and delta in Egypt, a ribbon of water and farmland running through the Sahara.

Sparse areas of the world

• Polar lands: Greenland, northern Canada, Siberia and Antarctica.
• Hot deserts: the Sahara (North Africa), the Atacama (Chile, about 20°S–27°S, one of the driest places on earth) and central Australia.
• Cold desert: the Gobi (Mongolia–China).
• Equatorial forests: the Amazon basin (Brazil) and the Congo basin (central Africa, on the Equator).
• High mountains: the Himalaya, Andes and Rockies.

Extreme densities

• Bangladesh has the highest density among large countries, at more than 1,100 persons per sq km.
• City-states are far higher: Monaco has about 19,000 persons per sq km and Singapore about 8,000, because almost all their land is city.

India

• Crowded: the Ganga plains and Kerala.
• Thinly peopled: the Thar desert, Ladakh and Arunachal Pradesh.
• India's density was 382 persons per sq km (Census 2011).
• India passed China as the world's most populous country in April 2023 (UN estimate). It reached 1,425,775,850 people at the end of April 2023 [2].

Don't confuse with

• Population density: distribution tells us where people live. Density tells us how many people live on each sq km. Density is the number that measures distribution.
• Physiological density: arithmetic density divides population by total land. Physiological density divides it by cultivable land only. Egypt looks moderate on the first measure and very crowded on the second.
• Population growth: distribution is the spread of people across space at one time. Growth is the change in their number over time. For example, the world had about 8.2 billion people in 2024, and the number is projected to peak at about 10.3 billion in the mid-2080s [3].

Prelims Hooks

• About 90 per cent of the world's people live on about 10 per cent of its land. The 10 most populous countries hold about 60 per cent of world population, and six of them are in Asia (NCERT).
• "Asia has many places where people are few and few places where people are very many" was said by George B. Cressey.
• Trap: Southeast Asia is a dense area, not a sparse one (NCERT exercise). Java and the Mekong and Irrawaddy deltas are among the most crowded places on earth.
• Matches: Atacama → Chile; Gobi → Mongolia–China; Irrawaddy delta → Myanmar; Mekong delta → Vietnam; Java → Indonesia; Congo basin → central Africa.
• Density = Population ÷ Area. 1,50,000 people on 100 sq km = 1,500 per sq km. India: 382 per sq km (Census 2011).
• India passed China in April 2023 (UN). China's population peaked at 1.426 billion in 2022 [2].

Mains Points

• The world's population is spread very unevenly, and the reasons differ for crowded and empty lands.
• Physical limits (cold, dryness, thick forest, steep slopes) keep polar lands, deserts, equatorial forests and high mountains nearly empty.
• Fertile alluvial and volcanic soils, monsoon rice farming, industry and long settlement crowd people into river plains, deltas and industrial belts.

• Cressey's idea applies at every scale. In India, the empty Thar, Ladakh and Arunachal Pradesh contrast with the crowded Ganga plains and Kerala, so plans must be made region by region, not from one national average.

• Arithmetic density can mislead planners; physiological density shows the real pressure on food land (GS-I and GS-III).

• About 95 per cent of Egyptians live on the Nile floodplain, and only about 4 per cent of the land can be farmed [4].
• Egypt loses about 2 per cent of its arable land per decade to spreading cities [4]. Seawater moving into the Nile delta has damaged about 15 per cent of its most fertile farmland [4].

• Lesson for India: protect fertile alluvial land in the Ganga plains and on the coasts as cities grow.

• India is now the most populous country and is still growing, while China is shrinking [2].

• Opportunity: a large working-age population, called the demographic dividend. India's fertility rate (average number of children born to a woman) was 2.0 in 2022, just below the replacement level of 2.1 (the number of children each generation needs to replace the one before) [2].
• Pressure: high density on the Indo-Gangetic plains and in Kerala strains land, water and cities.
• Policy needs: jobs, skills, urban planning and land-use planning.

Read more

• Patterns of population distribution and density