Effects of Changing Population Sizes (Cambridge (CIE) O Level Economics)

Revision Note

The Optimum Population

  • Overpopulation occurs when there are more people in a country/region than can be supported by its resources and technology and leads to

    • Higher levels of pollution

    • Higher crime rates

    • Higher unemployment or underemployment

    • Higher levels of food and water shortages 

    • Higher pressure on services such as hospitals and schools 

  • Underpopulation occurs when there are more resources available than the population can use effectively and may lead to

    • Fewer people paying tax which can lead to higher taxes

    • Underused resources, which can lead to wastage

    • A shortage of workers

    • Lower levels of exports and production which affects the wealth of an area

    • Fewer customers for goods and services 

  • Optimum population occurs when there is a balance between the number of people and the resources/technology available  
     

A graph showing GDP per capita vs. total population, with a peak labeled "Optimum Population" and declining sides labeled "Under Population" and "Over Population."
Optimum Theory of Population
  • The optimum population results in the highest standard of living

    • There are not so many people or so few resources that the standard of living falls

    • There are enough people to develop the resources of the country 

Examiner Tip

It is important to remember that over-population does not just mean there are a lot of people and under-population that there are few people. The terms refer to the balance between population and resources. There may be many people in a country, but it is only over-populated when there are too few resources to support that population.

Population Distribution

  • The characteristics of a population (the distribution of age, sex, ethnicity, religion etc), is known as the population structure  

  • The population structure is the result of changes in:

    • the birth rate

    • the death rate

    • net migration

  • The two main characteristics of age and sex can be shown on a population pyramid

Population pyramids

  • Population pyramids are used to display the gender and age structure of a given population

    • They illustrate the distribution of population across age groups and between male/female 

  • Population pyramids can be used to identify the following groups:

    • Young dependents 

    • Old dependents e.g number of retired people

    • Economically active (working population or labour force)

    • Dependency ratio 

Example 1 - Niger as a Less Economically Developed Country (LEDC)

Population pyramid of Niger in 2010. Blue bars represent male population and red bars represent female population across different age groups from 0 to 100.
Population Pyramid - Niger
  • LEDCs like Niger have a concave pyramid shape which indicates

    • High birth rate

    • Low life expectancy

    • High death rate but starting to decrease (people dying through every age group)

    • High infant mortality rate (significant decrease between 0-5)

    • Young dependent population dominates the distribution 

Example 2 - USA as a More Economically Developed Country (MEDC) 

Population Pyramid - USA 
Population Pyramid - USA 
  • This population pyramid indicates:

    • Decreasing birth rate  - there is a smaller population reading down from age 29

    • Increasing life expectancy - indicated by the relatively straight sides reaching the age of 70, followed by a good proportion of people living much longer

    • Decreasing death rate - indicated by the relatively straight sides reaching the age of 70

    • Low infant mortality - hardly any change between 0-9 years

    • Larger working age population - 15 to 69 represents a large proportion of the population 

Example 3 - Japan as a More Economically Developed Country (MEDC) 

Population Pyramid - Japan 
Population Pyramid - Japan 
  • This population pyramid indicates

    • Decreasing birth rate - indicated by decreasing population levels from age 29

    • Increasing life expectancy - indicated by the relatively straight sides reaching the age of 74, followed by a good proportion of people living much longer

    • Death rate is higher than the birth rate due to the ageing population

    • Low infant mortality

    • Ageing population - older dependent population with large proportion of the population older than 40 

Effects of Population Changes

  • Population changes can have major impacts within the economy resulting in changes to consumption, production, lifestyle, standards of living and government policies (fiscal, monetary and supply-side) 

  • Typical changes that occur are

    • Progressively ageing populations as economies develop

    • Falling birth rates as economies develop

    • Swings in net migration as influenced by war, famine, natural disasters and government policy 

Ageing populations

  • Many developed economies are experiencing ageing populations and an increase in the older dependent population

  • The implications of this include

    • Increased pension payments by governments

    • Increased need for care homes (public and private)

    • Increased pressure on the healthcare service and social care results in higher government spending

    • It also results in a smaller labour force and often Governments collect less tax

    • Firms suffer worker shortages

    • Labour shortages result in increased wage costs for firms  

Falling birth rates

  • Falling birth rates have the following impact on an economy

    • School closures due to fewer children

    • Future labour shortages 

    • Governments typically put in place incentives that encourage families to have more children

    • Governments may change the migration laws to encourage immigration so that labour shortages are prevented

      • Excessive immigration can change the nature and culture of different regions within a country 

Migration

  • In some countries migration can lead to an imbalance in the population structure e.g. the UAE has significantly more males than females 

  • Rapid population growth caused by migration can lead to

    • Increased pressure on services such as healthcare and schools resulting in increased costs for government

    • A shortage of housing which generates social issues in society

    • Increased traffic congestion which is a negative externality

    • Increased water and air pollution which are negative externalities

    • Food shortages

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