2. Overpopulation and Development

2. Overpopulation and
Learning Objectives
Explain the term overpopulation
Describe the causes of overpopulation
Describe the effects of overpopulation on
resources, income and society
Describe how technology can influence
population growth
Outline of work
Causes of overpopulation
Case study 1: Overuse of resources e.g. Aral Sea Region
Case Study 2: Effects of overpopulation on resources e.g.
Sahal region Africa
Case Study 3: Influence of society and culture e.g. India
Case Study 4: Impact of income levels e.g. Mezzogiorno
Case Study 5: Impact of technology on Population growth
e.g. agriculture and medical
2. Impact of population growth on rates of
Overpopulation Definition
• Overpopulation occurs when the number of
people in a region is greater than the ability of
the land to support them.
• I.e. there are more people than there are
resources to support them.
Carrying Capacity
• The number of people that a region can support with
its basic resources is called its carrying capacity.
• Basic resources = land, food, water, fuel and shelter.
Example: if a region contains 10 people but only have
enough resources for 9 then it is overpopulated.
If it contains 10 people and has resources for 20 then it is
not overpopulated.
Carrying Capacity
• What factors would increase the carrying
• What factors would decrease the carrying
The best or optimum population of an area is one
which can exist in a region and enjoy a good quality
of life without destroying the resources or
Cause of Overpopulation
1. High birth rates
2. Migration
3. Overuse of depletion of resources
Each of these have a case study. In your answer
You can write about all three or one in detail.
You could be asked for a cause or causes
1. High Birth Rates
• An increase in population increases the
demand for basic resources such as food, fuel
and water. If these are not available the area
will become overpopulated
2. Migration
• Migration can raise the population. People
choose to leave their homes for many reasons.
• Sometimes they may move to areas that are
already under stress due to soil erosion and
• Rural – urban migration also plays a part.
Shanty towns have to be built. Homelessness,
congestion and crime are also symptoms of an
overpopulated city region.
3. Overuse or depletion of resources
• If resources are overused they can not support
the population with a decent standard of
• When this happens many people have to leave
the area e.g Aral Sea in central Asia has
become depleted due to overuse of its water
Cause of overpopulation: Overuse or
depletion of resources
The Aral Sea
Aral Sea
• Activity: Read the photocopy of the Aral Sea in
central Asia case study.
• Summarise the most important parts into your
copies for eg the cause and the effects.
• http://www.youtube.com/watch?v=Z0Pi61SyV
Effect of overpopulation on
resources: Sahel Region of Africa
• Sahel region of Africa stretches
across the African continent.
• Sudan (largest country in Africa)
is a country where high birth
rates, migration and
environmental degradation have
combined to make parts of the
country overpopulated.
• (Also cause of overpopulation –
high birth rates )
Factors contributing to
overpopulation and overuse of soil
1. Birth Rates:
• Increasing population but the economic
development of Sudan has not kept up.
• It is in stage 2 of the demographic transition model.
• Sudan has a population of 43 million years.
• On average women have 5 children. Infant mortality
rate is high. Life expectancy is 58 years.
Half the population is under 18 so there is a high
dependency ratio.
Key Idea!
Population growth has led to overgrazing,
deforestation, and over cultivation.
In groups discuss some reasons for overgrazing,
deforestation and over cultivation
Some possible reasons….
• Cattle are a symbol of wealth and rank within society.
• There are now more families and each family needs more
cattle to survive. The increase in cattle leads people into
poverty as they overgraze the soil. The soil eventually
becomes damaged and useless for farming.
• Increased demand for fuel has led to deforestation and
land clearance.
• International debt has caused plantation owners to plant
huge areas of land under cash crops e.g. cotton and beans.
The land is not being left to rest between crops. This results
in overcultivation
2. Migration and Conflict
• Civil war and famine have caused
movements of people around Sudan.
• Many people hav being killed and up to
four million are at risk of attack. This
internal migration has affected the
population distribution, producing
overpopulation in areas that can not
provide services or employment.
• Also more than one million refugees from
Ethopia have entered the country.
3. Environmental Degradation
• Droughts over the last 30 years have reduced
Sudan’s food production. They occur most
often and last longer and longer.
• To provide water for people and cattle wells
have been dug.. This lowers the water table
and dries the soil even more.
The influence of Society and Culture on
• We are going to use India as the case study for
this topic. You should know about India from
regional geography
• In groups read page 301 of your text book.
Find out how India’s culture and society have
led to overpopulation.
• Write your findings into your notes copy
Impact of Income Levels
• Can be broken into two parts
- Effects of rising incomes
- Effects of low incomes e.g. Mezzogiorno Italy
Read page 301 and 302 of your books.
Impact of technology on Population Growth
Increased food supply leads to population growth.
More food = healthier lifestyle and life expectancy increases.
We now have the technology to grow enough food to feed
1,000 people for a year on an area the size of a soccer pitch.
Biotechnology has created and developed new varieties of crop
that can survive drought nd produce more seeds.
Chemicals control pests.
Irrigation methods.
Computer controlled systems are used to water, heat and light
the greenhouses
Impact of technology on population
growth (Medical)
Advances in medicine has decreased the rate of
population growth this is because
People living longer because of access to
immunisation, primary healthcare and disease
eradication programmes.
Family planning
Status of women
As health conditions improve more children are
likely to survive so they are choosing to have fewer
Case Study: HIV/AID treatment in
South America.
Activity: Read the case study and answer the following
1. Why will the population in some areas of the world
decrease over the next 40 years?
2. Why is there a delay in the use of effective medicines in
South Africa?
3. Pick out three facts about Aids and South America that
surprised you.
4. Summarise the governments influence on the use of
HIV/AIDS medicines
5. Summarise the influence of multinational companies on
HIV/AIDs treatment in South Africia
Impact of Popuation Growth on
• Population growth and developed countries
• Population growth and developing countries
Population growth and developed countries
1. Developed countries need population growth to
provide a labour force for industry and services.
2. Population growth provided a market for products
such as textiles
3. Rising population moved from rural to urban areas.
Fewer farms were needed to feed the urban
population because of increases in food.
4. Industrialisation was encouraged by the creation of
trading systems
5. Tax revenue allowed for investment in education,
health and services such as sanitation. This led to an
incerease in life expectancy and lowered birth rates.
6. As a result these countries passed through the
demographic transition model faster than other
Population Growth and Developing Countries
1. Increased population = increased need for food,
infrastructure and services.
2. Developing countries are benefiting from better
healthcare but are not experiencing economic
development and industrialisation that Europe did.
3. Few jobs to support the population. Lower incomes
and cannot afford to provide education, healthcare
or state support. Large families are needed to
provide economic security.
4. Developing countries have a very young age
dependency ratio and there will be an increase in
demand for services and jobs. They will need
financial help
Chapter Summary
• Traffic light your learning objectives.
• Are you typical?