In Eight Billion People you learned that about 8.2 billion people lived on Earth in 2024 (UN). They are not spread evenly. A few regions hold most of humanity, and huge areas hold almost no one. Using location and the physical map, you can explain why.
Key idea
Most people live in four clusters: East Asia, South Asia, Southeast Asia and Europe. Nearly 60 percent of the world's people live in Asia (UN, 2025). People crowd onto low, well-watered land with good soil and a mild climate, often near coasts and rivers. Very dry, very cold, very high and very wet places have few people.
Why it works
For most of history nearly everyone farmed, and farming needs flat land, water, good soil and a growing season. River valleys and deltas, such as the Ganges in South Asia and the Yangtze in China, gave all of these and could feed dense populations. Places that cannot be farmed easily, such as the Sahara, Siberia, the Australian outback and high mountains, stayed thinly settled, and they still are. The part of Earth where people live permanently is called the ecumene.
Worked examples
Worked example: Size is not population
Canada's land area is roughly 70 times Bangladesh's, yet Bangladesh has several times as many people. Why?
- Most of Canada is cold: forests and tundra with short growing seasons. Most Canadians live in a narrow band near the U.S. border.
- Bangladesh lies on the warm, wet, fertile delta of the Ganges and Brahmaputra rivers.
- Fertile, warm land can feed many people on a small area.
Answer: Bangladesh's land is warm, wet and fertile; most of Canada is too cold to farm.
Worked example: Where in Egypt?
Egypt is about one million square kilometers, mostly desert. Where would you expect its people to live?
- Water is the limiting factor in a desert.
- The Nile River brings water and fertile soil through the desert.
- So people crowd into the Nile valley and delta: over 95 percent of Egyptians live there.
Answer: Along the Nile valley and in its delta.
Common mistake
Students assume population follows country size. Russia, Canada and Australia are among the largest countries but hold few people for their size; small, fertile river valleys and deltas can be crowded. Check a population claim against the physical map: where are the water, the flat land and the growing season?