Understanding Overpopulation (Leaving Cert Geography): Revision Notes
Understanding Overpopulation
Introduction to population concepts
Population geography examines how many people live in different areas and whether this number is sustainable. Understanding population requires learning about three key concepts that describe the relationship between people and available resources in any given region.
What is overpopulation?
Overpopulation happens when the number of people living in a region is greater than the capacity of the natural resources available to them. The maximum number of people a region's natural resources can support is referred to as the region's carrying capacity. Therefore, a region is said to be overpopulated when it has exceeded its carrying capacity.
Understanding overpopulation properly
Many students make the mistake of confusing overpopulation with high population density. However, a region with high population density is not necessarily overpopulated.
Real-World Comparison: Density vs. Overpopulation
The Netherlands Example:
- Population density: 501 people per km²
- Status: Not overpopulated
- Reason: High level of resources available
Mali Example:
- Population density: 14.5 people per km²
- Status: Considered overpopulated
- Reason: Lacks resources to provide adequate standards of living
Overpopulation is not permanent
It's important to understand that overpopulation is not a permanent characteristic of a region. Ireland was overpopulated during the Great Famine (1845-9) because of crop failure of the primary food (the potato) due to blight. Many argue that Ireland remained overpopulated until the 1950s due to a poor economy and low standard of living.
This historical example shows how overpopulation can be temporary - caused by specific events like natural disasters, economic collapse, or resource depletion, and can be resolved through improved conditions over time.
Examples of overpopulation impacts
As the world's population continues to rise rapidly, it puts increasing strain on our limited natural resources. Water, arable land and fossil fuels are the most important natural resources in the world and are vital to human survival. Examples of overpopulation effects include:
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Desertification in the Sahel has led to the destruction of arable land, dwindling water supplies and famine. Desertification itself is caused by increased drought due to climate change and poor management of resources.
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Pollution in China: It is estimated that 80 per cent of China's arable land has been polluted due to agricultural chemicals and industrial waste.
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Urban slums: The slums of Kolkata and São Paulo are examples of the impacts of overpopulation in urban areas.
What is underpopulation?
Underpopulation happens when a region does not have enough people to fully exploit all available natural resources.
How underpopulation occurs
Underpopulation frequently occurs in developed, highly industrialised countries that experience low birth rates. Due to the low birth rates, these countries now suffer from labour shortages. As a result, inward migration is needed to fill the labour deficits.
Real-world example
Case Study: Ireland's Celtic Tiger Era
The Boom Period:
- Time: Celtic Tiger era
- Issue: Booming economy led to worker shortages
- Affected sectors: Especially the tertiary sector
- Solution: Inward migration to fill labour deficits
The Change:
- 2008: Economic recession occurred
- Result: Large-scale unemployment
- Outcome: Emigration of young Irish adults and previous migrants
Australia provides another clear example of an underpopulated country that relies on immigration to fill its labour deficits, as shown by consistent immigration patterns over decades.
What is optimum population?
Optimum population is the exact number of people required to exploit natural resources in order to give the highest possible standard of living.
Why optimum population is theoretical
Optimum population represents the ideal balance where a region has exactly the right number of people to make the best use of its natural resources whilst providing the highest possible standard of living. However, it is highly unlikely that any country or region remains at its optimum population for any length of time. This is because of the large number of variables, such as:
- Population growth or decline
- Global markets
- Employment opportunities
- Migration patterns
The theoretical nature of optimum population means it's more useful as a concept for understanding population dynamics than as a practical target for policy makers.
Carrying capacity and factors affecting it
Carrying capacity is the maximum number of people a region's natural resources can support.
The carrying capacity of a region can be influenced by various factors:
Factors That Can Increase Carrying Capacity:
- Technology: Improvements in agricultural technology, medical advances, and industrial processes
- Resource management: Better management of water, soil, and other resources
- Economic development: Access to global markets and trade
Factors That Can Decrease Carrying Capacity:
- Climate change: Drought, changing weather patterns, and environmental degradation
- Poor resource management: Overuse or misuse of natural resources
The global impact of population and resources
Carbon footprint disparities
An important aspect of understanding overpopulation is recognising the unequal impact different populations have on global resources. While overpopulation is often considered to be a developing world problem, the reality is more complex:
Global Carbon Output Distribution (2016):
Developing Countries:
- Carbon contribution: 52% of world's output
- Population: Over 80% of world's population
Developed Countries:
- Carbon contribution: 48% of world's output
- Population: Less than 20% of world's population
Per Capita Carbon Footprints:
- Mali: 0.6 tonnes per capita
- Ireland: 11 tonnes per capita
- USA: 20.4 tonnes per person (highest average)
The key insight
Key Understanding: The people worst affected by overpopulation are often not responsible for causing it. The global disparity in resource consumption means that developed nations with smaller populations often place greater strain on global resources than developing nations with much larger populations.
Remember!
Key Points to Remember:
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Overpopulation occurs when population exceeds the carrying capacity of available natural resources, not simply when population density is high
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Underpopulation happens when there aren't enough people to fully utilise available resources, often leading to labour shortages in developed countries
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Optimum population is the theoretical ideal number of people for maximum standard of living, but is rarely maintained due to changing variables
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Carrying capacity can be increased through technology and better resource management, but decreased by climate change and poor management
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The impacts of overpopulation (like desertification and pollution) often affect those least responsible for causing the problem globally