The World Population: Distribution, Density, and Growth

(Class 12 Geography – CBSE, 2025–26)

1. Introduction

• Population is the central element of Human Geography.
• People are producers, consumers, and transformers of Earth’s surface.
• Study of population helps us understand:
  🔹 Where people live (distribution)
  🔹 How densely they live (density)
  🔹 How population changes (growth and dynamics)

👉 Without population, resources, environment, and development have little meaning.

2. Distribution of World Population

World population is unevenly distributed – some regions are very crowded while others are nearly empty.

(i) Global Patterns

• Total World Population (2025 estimate) → 8.1 billion approx.
• Highly populated areas → South Asia, East Asia, Europe, and Eastern North America.
• Sparsely populated areas → Deserts (Sahara, Atacama), Polar regions, Dense forests (Amazon, Congo), High mountains (Himalayas, Andes).

(ii) Factors Affecting Distribution

1. Physical Factors
   • Relief: Plains (e.g., Ganga plains) → dense population; mountains (e.g., Himalayas) → sparse.
   • Climate: Moderate climates (Europe) → dense; extreme hot/cold (Sahara, Antarctica) → sparse.
   • Soil fertility: River valleys (Nile, Ganga) → dense.
   • Water availability: Near rivers, lakes, coasts → dense population.
2. Economic Factors
   • Industrial regions (Western Europe, NE USA, Japan) → dense.
   • Mining areas attract settlements.
   • Regions with poor infrastructure (Sahara, interiors of Amazon) → sparse.
3. Social & Cultural Factors
   • Places of cultural/religious significance attract population (Varanasi, Mecca).
   • Regions with history of stability and peace attract higher density.

👉 Exam Tip: Always link physical and human factors in answers.

3. Density of Population

Definition: Density = Population ÷ Area

• Average World Density (2025) → about 56 persons per sq. km.
• But varies greatly from region to region.

(i) Types of Density

1. Arithmetic Density → population per unit area.
2. Physiological Density → population per unit of arable land.
3. Agricultural Density → farmers per unit of arable land.

👉 Example:

• Egypt: Arithmetic density = low (because of desert area).
• Physiological density = very high (population concentrated along Nile valley).

(ii) Regional Examples

• Very High Density (>500 persons/sq km): Bangladesh, Singapore, Netherlands.
• Moderate Density (100–200): China, USA.
• Low Density (<10): Australia, Namibia, Mongolia.

4. Growth of Population

Population growth = Change in population over time.

(i) Natural Growth

Difference between birth rate and death rate.

(ii) Positive Growth

When births + immigrants > deaths + emigrants.

(iii) Negative Growth

When deaths + emigrants > births + immigrants.
(E.g., some East European countries show negative growth).

5. Historical Perspective of Population Growth

1. Early Period (till 1800 AD)
   • Very slow growth due to high death rates (diseases, famines, wars).
2. After Industrial Revolution (1750 onwards)
   • Rapid growth in Europe and North America due to better food, medicine, sanitation.
3. 20th Century – Population Explosion
   • Sharp decline in death rate but birth rate remained high.
   • World population grew from 2.5 billion (1950) → 8.1 billion (2025).

6. Patterns of Population Growth

1. High Growth Regions
   • Africa, South Asia, Latin America.
   • Features: High birth rate, declining death rate.
2. Low Growth Regions
   • Europe, Japan.
   • Features: Low birth rate, aging population, even decline.

7. Population Change Components

1. Birth Rate
   • Number of live births per 1000 population per year.
2. Death Rate
   • Number of deaths per 1000 population per year.
3. Migration
   • In-migration (immigration) increases population.
   • Out-migration (emigration) decreases population.

8. The Demographic Transition Model (DTM)

Explains population growth in relation to birth and death rates.

Stages:

1. Stage I: High Stationary
   • High birth + high death = low growth.
   • Pre-industrial societies.
2. Stage II: Early Expanding
   • Birth rate high, death rate falls rapidly.
   • Result: population explosion.
   • Example: India (till 1980s), many African countries.
3. Stage III: Late Expanding
   • Birth rate declines, death rate low.
   • Population growth slows.
   • Example: Brazil, China.
4. Stage IV: Low Stationary
   • Both birth & death rates low.
   • Stable/zero growth.
   • Example: Japan, Germany.
5. Stage V (Proposed): Declining Population
   • Birth rate falls below death rate.
   • Example: Some East European countries.

9. Importance of Studying Population Distribution, Density, and Growth

• Helps in economic planning.
• Indicates resource pressure and carrying capacity.
• Basis for social infrastructure: schools, hospitals, housing.
• Helps in solving global issues → poverty, migration, urbanization, unemployment.

10. Key Terms (For Exams)

• Population Density: People per unit area.
• Population Explosion: Very rapid rise in population.
• Birth Rate: Number of births per 1000 population/year.
• Death Rate: Number of deaths per 1000 population/year.
• Migration: Movement of people across regions.
• Carrying Capacity: Maximum population an area can support.
• Demographic Transition: Changes in population growth with development.

11. Case Studies / Examples

• Bangladesh → highest density (~1265 persons/sq km).
• Australia → very low density (~3 persons/sq km).
• Japan → aging population, low growth.
• India → second most populated country; rapid growth but fertility rate declining.
• China → population control through “One-Child Policy” (1979–2016).

12. Sample Answer Frames (Exam Writing Help)

(i) 3 Marks Question: Define population density.

Answer Frame:
Population density is the ratio of population to land area. It expresses how many people live per unit area of land. For example, Bangladesh has a very high density, while Australia has a very low density.

(ii) 5 Marks Question: Explain factors influencing population distribution.

Answer Frame:

• Relief → Plains dense (Ganga plain), mountains sparse (Himalayas).
• Climate → Temperate dense (Europe), deserts sparse (Sahara).
• Soil → Fertile valleys dense (Nile, Ganga).
• Water → Rivers/lakes attract settlements.
• Economy → Industries (Japan, Germany) dense.
  Thus, both physical and human factors combine to influence distribution.

(iii) 6 Marks Question: Discuss stages of demographic transition.

Answer Frame:

• Stage I: High birth + high death → low growth.
• Stage II: High birth + declining death → population explosion.
• Stage III: Declining birth + low death → slowing growth.
• Stage IV: Low birth + low death → stable population.
• Stage V: Birth below death → declining population.
  This model explains how population growth shifts with development.

13. FAQs (Quick Revision)

Q1. Which region is most densely populated in the world?
A: South Asia (India, Bangladesh, Pakistan).

Q2. Define physiological density.
A: Population per unit of arable (cultivable) land.

Q3. What is population explosion?
A: Very rapid and sudden rise in population, especially after 1950s.

Q4. Name two regions with negative growth of population.
A: Japan, Germany.

Q5. What does the Demographic Transition Model show?
A: It shows how population growth changes with birth and death rates over stages of development.