Demography is the study of human populations — their size, structure, and change. — Warren Thompson
2.1 World Population Distribution
Population is unevenly distributed across the globe. About 90% of people live on roughly 10% of the land surface.
Areas of high concentration:
- East and South Asia (China, India, Japan, Indonesia)
- Europe (especially Western and Central)
- North-eastern United States
Areas of sparse population:
- Hot deserts (Sahara, Arabian)
- Cold polar regions (Greenland, Antarctica)
- Dense tropical rainforests (Amazon, Congo)
- High mountainous regions (Himalayas, Andes)
2.2 Factors Affecting Distribution
| Factor | Effect |
|---|---|
| Climate | Moderate climates attract settlement |
| Relief | Plains favoured over mountains |
| Soil | Fertile soils support agriculture |
| Water | Rivers and coasts enable livelihoods |
| Minerals | Mining attracts population |
| Accessibility | Transport corridors concentrate people |
Social, economic, and political factors (history, government policy, conflict) also shape distribution.
2.3 Density of Population
Arithmetic density = Total population ÷ Total area (persons per sq km)
Physiological density = Population ÷ Arable land
Agricultural density = Agricultural population ÷ Arable land
World average density is rising, but regional contrasts are stark — from over 400 persons/sq km in Bangladesh to fewer than 1 in Greenland.
2.4 Trends in Population Growth
- World population crossed 8 billion in 2022
- Growth rate has declined since the 1960s peak but absolute numbers still rise
- Demographic transition: high birth and death rates → falling death rates → falling birth rates → low growth
Components of growth:
- Natural increase = Birth rate − Death rate
- Migration — net in-migration adds to population in receiving areas
2.5 Doubling Time and Explosion
At 1% annual growth, population doubles in ~70 years; at 2%, in ~35 years. The population explosion of the 20th century resulted from medical advances lowering mortality while fertility remained high in many regions.
Chapter Summary
- Population is concentrated in Asia, Europe, and parts of the Americas
- Climate, relief, soil, water, minerals, and accessibility shape distribution
- Density measures include arithmetic, physiological, and agricultural
- Global growth is slowing but absolute numbers continue to rise
- Demographic transition explains stages of population change
Exercises (NCERT)
- Exercise 1 — factors influencing population distribution
- Exercise 2 — types of population density
- Exercise 3 — trends in world population growth and demographic transition