Global population trends and population pyramids

Global trends and projections

UN World Population Prospects 2024:

• World population reached 8.2 billion in mid-2024.
• It is projected to peak at about 10.3 billion in the mid-2080s and fall slightly to 10.2 billion by 2100.
• Global fertility was 2.3 births per woman in 2024, down from 3.3 in 1990; more than half of countries have fertility below 2.1.
• 63 countries and areas (28% of world population) have already passed their population peak.
• Life expectancy reached 73.3 years in 2024; by the late 2070s people aged 65 and over (2.2 billion) are projected to outnumber children under 18.

Projections are uncertain because they depend on assumptions about future fertility, mortality and migration; small changes in fertility make big differences over decades.

Demographic rates

• Crude birth rate (CBR): births per 1,000 people per year.
• Crude death rate (CDR): deaths per 1,000 people per year.
• Natural increase (%) = (CBR - CDR) / 10.
• Infant mortality rate: deaths of children under one year old per 1,000 live births.
• Total fertility rate (TFR): average number of children per woman; about 2.1 is replacement level.

Skill (11): population pyramids

• A wide base and narrow top: high birth rate, youthful population, rapid growth.
• Straight sides: low birth and death rates, stable.
• A narrowing base (constrictive): falling fertility, an ageing population that may decline.
• Bulges and notches show past baby booms, wars or migration (for example more working-age men in a country receiving labour migrants).

Comparing pyramids for the same country over time shows ageing as the bulge moves up.

Worked example

A country has a crude birth rate of 35 per 1,000 and a crude death rate of 9 per 1,000. Calculate its rate of natural increase.

1. Natural increase per 1,000 = 35 - 9 = 26
2. As a percentage: 26 / 10

Answer: 2.6% a year.

Check yourself

1. A country has a CBR of 22 per 1,000 and a CDR of 7 per 1,000. Calculate its natural increase as a percentage.
   Show answer

   1.5 %. (22 - 7) / 10 = 1.5%.

2. World population is projected to grow from 8.2 billion (2024) to a peak of 10.3 billion. Calculate the percentage increase to 1 decimal place.
   Show answer

   25.6 %. 2.1 / 8.2 x 100 = 25.6%.

3. Global fertility fell from 3.3 (1990) to 2.3 (2024) births per woman. Calculate the percentage fall to 1 decimal place.
   Show answer

   30.3 %. 1.0 / 3.3 x 100 = 30.3%.

4. A population pyramid with a very wide base that narrows quickly towards the top shows
   • an ageing population
   • high birth rates and a youthful population
   • zero population growth
   • a population dominated by migrants aged over 65
   Show answer

   high birth rates and a youthful population. Many children, fewer older people.

5. Replacement-level fertility is about
   • 1.0 child per woman
   • 4.0 children per woman
   • 10 births per 1,000
   • 2.1 children per woman
   Show answer

   2.1 children per woman. Slightly over 2 allows for child deaths.

6. The infant mortality rate measures
   • deaths of all children under 18 per 1,000 people
   • deaths of children under one year old per 1,000 live births
   • births per 1,000 women
   • deaths per 1,000 people
   Show answer

   deaths of children under one year old per 1,000 live births. It is a sensitive indicator of health care and development.

7. Suggest why future population projections are uncertain.
   Show answer

   They depend on assumptions about future fertility, mortality and migration; for example fertility may fall faster or slower than expected because of changes in education, contraception and the economy.. Uncertain assumptions about fertility, mortality and migration.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Geography specification (Issue 3, September 2025)
• UN DESA: World Population Prospects 2024, key messages (July 2024)
• Pearson principal examiner report, WGE01 Global Challenges, June 2025

Last updated 8 November 2026. Spotted a mistake? Tell us.