The world’s population of over 8 billion people is unevenly distributed across the planet’s land surface. Understanding this distribution — where people live and why — is foundational to Unit 4 Population Geography.
Ecumene vs Non-ecumene
- The ecumene refers to permanently inhabited areas of the world
- The non-ecumene refers to areas not permanently inhabited: extreme deserts, high mountains, polar ice
- Approximately 90% of the world’s population lives on just 10% of its land area
Hemispheric distribution
- ~90% of the world’s population lives in the Northern Hemisphere
- ~80% lives between the Tropics and 60°N latitude
- Over 50% lives in Asia
Continental distribution (approximate 2024)
| Region | Population (millions) | % of World |
|---|---|---|
| Asia | 4,700 | ~58% |
| Africa | 1,450 | ~18% |
| Europe | 750 | ~9% |
| Latin America & Caribbean | 660 | ~8% |
| North America | 380 | ~5% |
| Oceania | 45 | ~0.5% |
Highest population densities:
- Indo-Gangetic Plain (India, Bangladesh, Pakistan) — >1,000 people/km² in some districts
- Eastern China (Yellow River, Yangtze deltas)
- Java, Indonesia — one of the most densely populated large islands on Earth (~150 million people)
- Rhine Valley and North European Plain
- Nile Delta, Egypt — >1,500 people/km²
- North-eastern USA (Boston–Washington megalopolis)
Sparsely populated areas:
- Sahara and Arabian deserts
- Siberian taiga and tundra
- Central Australian interior
- Amazon Basin (despite being relatively populous by regional standards)
- Tibetan Plateau and Himalayan interior
- Greenland and Antarctica
Population distribution reflects a combination of physical, economic, historical and political factors:
Physical factors favouring high density:
- Flat, fertile agricultural land (alluvial plains, river valleys)
- Moderate climate with reliable rainfall (200–1,500 mm/year)
- Proximity to fresh water
- Access to coastlines and navigable rivers (trade)
- Low altitude (most people live below 500 m)
Physical factors limiting population:
- Extreme cold (polar regions: permafrost, short growing seasons)
- Extreme aridity (deserts: <250 mm rainfall cannot support agriculture)
- Extreme altitude (above ~3,500 m: low oxygen, poor soils, harsh climate)
- Steep terrain (limits agriculture and settlement)
Human factors:
- Historical agricultural civilisations formed in fertile river valleys (Nile, Indus, Yellow, Tigris-Euphrates)
- Industrial Revolution concentrated population in coal fields and ports (UK, Germany, north-eastern USA)
- Colonial-era trade routes and ports attracted settlement
- Continued urban migration amplifies existing concentrations
Arithmetic (crude) density: Total population ÷ total land area
Physiological density: Total population ÷ arable land area (better indicator of pressure on agricultural land)
Agricultural density: Agricultural population ÷ arable land area
KEY TAKEAWAY: Global population is concentrated in a band between the tropics and 60°N, particularly in South and East Asia, Western Europe, and north-eastern North America. Distribution reflects the intersection of physical opportunity (fertile soils, water, mild climate) and historical human processes (agricultural origins, industrialisation).
EXAM TIP: When describing population distribution, always distinguish between high-density and low-density areas, name specific regions or countries, and provide at least one explanatory factor linking distribution to physical or human geography.
COMMON MISTAKE: Students often describe distribution without linking it to causes. A complete response identifies the pattern AND explains why it exists (e.g., “The Indo-Gangetic Plain supports high population density because of its flat topography, fertile alluvial soils and reliable monsoonal rainfall, which sustain intensive rice and wheat agriculture”).
