Population Change (Cambridge International IGCSE Environmental Management)

Causes of population change

• Human populations are always changing
• Some countries grow quickly, while others grow slowly or even shrink
• These changes occur due to birth rates, death rates and migration
• These factors help to understand population growth, movement and urbanisation

Birth rates

Birth rate: children per woman

• Birth rate refers to the average number of children born to each woman
• High birth rates cause rapid population growth because more people are being added to the population
• Birth rates are often higher in low-income countries due to limited access to contraception and family planning
• Cultural and religious beliefs can encourage large families
• In many high-income countries, birth rates are low because women are more likely to work, be educated, delay marriage and have fewer children

Death rates

Death rate and life expectancy

• Death rate measures how many people die in a population over a period of time
• Life expectancy is the average number of years a person is expected to live
• Low death rates and high life expectancy increase population size
• Improved healthcare, clean water and better nutrition reduce death rates
• High death rates may be caused by disease, poor healthcare, famine or conflict

Migration

Types of migration

• Migration is the movement of people from one place to another
• Emigration is when people leave a country
• Immigration is when people enter a country
• Migration changes population size and structure, especially age and sex balance

Push and pull factors

• Push factors are negative conditions that encourage people to leave an area

• Examples include:

  • Unemployment
  • Lack of services
  • Low income
  • Environmental problems such as drought

• Pull factors are positive conditions that attract people to a new place

• Examples include:

  • Better jobs
  • Education
  • Healthcare
  • Improved living conditions

Rural–urban migration

• Rural–urban migration occurs when people move from the countryside to towns and cities
• People are pushed from rural areas by lack of jobs, poor services and mechanisation of farming
• People are pulled to cities by employment, education and healthcare opportunities
• This increases urban population size while reducing rural population

Exam Hint Do not confuse migration with natural population change.

Urbanisation

Growth of urban areas

• Urbanisation is the increase in the proportion of people living in towns and cities

• It is caused by rural–urban migration and natural increase in urban populations

• Urbanisation is often rapid in low- and middle-income countries

  • Rates of urbanisation are lower in HICs, as a high percentage of the population already lives in towns and cities
  • In some HICs, rates of urbanisation may start to decrease as counter-urbanisation occurs

• Fast urban growth can lead to overcrowding, housing shortages and pressure on services

• Planned urbanisation can improve living standards and economic development

• Government policies – Some governments actively encourage urban growth by investing in cities and infrastructure

  • China, for example, has rapidly urbanised through deliberate government planning
  • Other countries might focus more on rural development

Exam Hint Natural increase does not include the inward migration of people to a place, just the number of births vs. the number of deaths. E.g. On one street, there were five new migrants, 10 births, and two deaths. The natural increase is eight people because the migrants chose to move there. If they went on to have children, the natural increase rate would include those offspring.

Worked Example Describe and explain how urbanisation affects population change.

[6 marks]

Answer

Urbanisation is the increase in the proportion of people living in urban areas. [1] It is caused by rural–urban migration [1] as people move to cities for jobs and services. [1]

Urban areas also grow through natural increase [1] because young adults have children. [1] As a result, cities grow rapidly while rural populations may decline. [1]

Marking guidance

• 1 mark [1] for an accurate definition of urbanisation.
• Up to 2 marks for explaining rural–urban migration.
• Up to 2 marks for explaining natural increase.
• 1 mark [1] for the overall effect on population distribution.

Examiner tip

High-mark answers include both migration and natural increase when explaining urbanisation.