Population growth and decline Cambridge IGCSE Geography revision
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In plain words
There are more than eight billion people on Earth, and the number is still rising. But it is not rising everywhere. Some countries double in a generation, and others are shrinking. The difference comes down to births, deaths and migration.
8 things to know
- World population grew slowly for most of history, then very rapidly from about 1950. Growth is now fastest in low-income countries, especially in Africa, and is slow or negative in many high-income countries.
- The birth rate is the number of live births per 1000 people per year. The death rate is the number of deaths per 1000 people per year.
- Natural increase is the birth rate minus the death rate. The fertility rate is the average number of children a woman has.
- A country's population changes through natural increase and through migration.
- Birth rates are high where children are needed to work and to support parents in old age, where many infants die, and where women have little education or access to contraception. Death rates fall with better healthcare, clean water and food.
- A pro-natalist policy encourages people to have more children, with payments, paid parental leave and cheap childcare. An anti-natalist policy tries to reduce births, with family planning, education, incentives or penalties.
- The demographic transition model (DTM) shows how birth and death rates change as a country develops, in five stages: both high; death rate falling; birth rate falling; both low; birth rate below death rate.
- The model's strengths: it is simple, it lets countries be compared, and it helps to predict change. Its limitations: it is based on what happened in Europe, it ignores migration, government policy and events such as war, and it gives no timescale.
Worked example
A country has a birth rate of 34 per 1000 and a death rate of 9 per 1000. Calculate its natural increase, and state the stage of the DTM it is in.
- Natural increase = 34 − 9 = 25 per 1000, which is 2.5% a year.
- The birth rate is high and the death rate has fallen to a low level.
- That is stage 2 of the model: rapid population growth.
Tips and tricks
- Natural increase leaves out migration. If a question says "population change", migration may need mentioning.
- For policies, describe what the government did and then say what happened as a result. An evaluation needs both.
It lands in your notebook with its questions as flashcards.
Population growth and decline: 6 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What is natural increase?
Migration is not included.
A country has a birth rate of 20 and a death rate of 8 per 1000. What is its natural increase?
20 − 8.
What is a pro-natalist policy?
It is used by countries with low birth rates.
In which stage of the DTM does population grow fastest?
The death rate has fallen but the birth rate is still high.
Which is a limitation of the DTM?
Migration can change a population greatly.
Where is population growing fastest today?
Birth rates there are still high while death rates have fallen.
Quiz
6 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 10 marks. Write your answers on paper, then check them.
Population growth and decline
Cambridge IGCSE Geography 0460 · 10 marks · papermunch.org
Name ______________________________ Date ______________
Define birth rate and natural increase.[2]
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The birth rate is the number of live births per 1000 people per year. Natural increase is the birth rate minus the death rate.
Explain two reasons why birth rates are high in some low-income countries.[4]
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Children are needed to work on the land and to look after their parents in old age. Many women have little education or access to contraception. (Also: high infant mortality, so parents have more children.)
Describe two limitations of the demographic transition model.[4]
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It is based on the experience of European countries, so others may not follow it. It does not include migration or the effect of government policies.
Answers: Population growth and decline
- 1. The birth rate is the number of live births per 1000 people per year. Natural increase is the birth rate minus the death rate.
- 2. Children are needed to work on the land and to look after their parents in old age. Many women have little education or access to contraception. (Also: high infant mortality, so parents have more children.)
- 3. It is based on the experience of European countries, so others may not follow it. It does not include migration or the effect of government policies.



