Global population: distribution, density, growth trends, components of change

Global Population Distribution

Think of the world as a giant pizza 🍕. Some slices (countries) are thickly topped with people, while others are almost empty. The majority of people live in Asia, especially in densely populated countries like China and India, while places like Australia and Canada are much less crowded.

Population Density

Population density is the number of people living per unit area. It’s like counting how many students sit in each classroom.

Formula: Density = Population ÷ Area

Example: If a city has 1,000,000 people and covers 500 km², then

Density = 1,000,000 ÷ 500 = 2,000 people/km²

That’s a very crowded city – think of a packed stadium!

Population Growth Trends

Population growth can be visualised like a snowball rolling downhill – it starts small and can grow rapidly.

1. Historical growth – From 1.6 billion in 1900 to 8 billion today.
2. Future projections – By 2100, the world may reach 10 billion.
3. Regional differences – Some regions (e.g., sub‑Saharan Africa) are growing fast, while others (e.g., Europe) are stabilising or shrinking.

Key drivers: birth rates, death rates, and migration.

Components of Population Change

Population change is the result of four main components:

• Births (B) – New people added.
• Deaths (D) – People who leave the population.
• Immigration (I) – People moving into a country.
• Emigration (E) – People moving out of a country.

Mathematically:

$P_{t+1} = P_t + B - D + I - E$

Where $P_t$ is the population at time t.

Example: If a country has 10 million people, 200,000 births, 150,000 deaths, 30,000 immigrants, and 20,000 emigrants, the new population is:

$10,000,000 + 200,000 - 150,000 + 30,000 - 20,000 = 10,060,000$

Migration Patterns

Migration is like a river that carries people from one place to another.

• Push factors – Reasons that make people leave (e.g., war, drought).
• Pull factors – Reasons that attract people (e.g., jobs, safety).

Example: Many people move from rural villages in India to cities like Mumbai for better job opportunities.

International migration flows: 🌍➡️🌎

Exam Tips

• Always define key terms (e.g., population density, migration).
• Use diagrams or tables to show data clearly.
• Show calculations step‑by‑step when asked for population change.
• Remember the push/pull framework when discussing migration.
• Keep answers concise but complete.