Population Growth Dynamics (AQA A Level Geography)

Balancing Population & Resources

Balancing Population and Resources

• The concept of population ecology refers to how humans interact with their environment to change in number over space and time

  • Also known as population growth dynamics

• Global population has grown exponentially over the past 200 years

  • In 1800 it was 1 billion

  • In November 2022 it reached 8 billion

• Due to humans’ ability to resist the limiting environmental factors

  • E.g.s of limiting factors are disease and food supply

  • Humans have overcome these by finding

    • Medicines and vaccines to reduce or control rates of disease

    • Technology to increase food supply to allow for population growth

• Continued population growth puts pressure on scarce resources

  • The balance between population and resource use determines a place’s standard of living

  • Careful management of population and resources is needed to maximise income per capita

  • Countries aim to achieve a perfect balance between population and resources, known as optimum population 

  • An imbalance between population and resources leads to overpopulation or underpopulation

• Population structure can also impact the population and resource balance

  • Countries with a low dependency ratio are more likely to develop resources efficiently and so:

    • Achieve economic growth

    • Have an increased standard of living

    • Allow a rise in population to be supported

  • Countries with a high dependency ratio will spend precious resources on looking after the elderly or young dependents and so will struggle to:

    • Grow the economy

    • Support a population increase without negative social and economic issues

Concepts of Carrying Capacity and Ecological Footprint

• The maximum stable population size that an environment can support is known as the carrying capacity

• The size of the Earth’s carrying capacity is determined by:

  • Size of the population

  • Level of resource consumption

  • Technological innovation

  • Level of wealth

• If resources are consumed at sustainable rates, a larger population may be supported

• Countries going through industrialisation tend to consume and waste resources at unsustainable levels which leads to a lower carrying capacity

• Technological innovation can either lead to:

  • Increases in supply of resources such as energy and minerals, lowering carrying capacity

• Or:

  • Improved resource use efficiency and a higher carrying capacity

• Wealthier countries usually have a larger carrying capacity than poorer countries because:

  • They export waste to poorer countries

  • They import products from poorer countries

  • This means that although poorer countries use fewer resources, they are supporting the resource use of the richer countries

• An ecological footprint is a measure of a person’s or group’s use of natural resources

  • It is the amount of global heactares (gha) available for use by each person on the planet

  • It also shows the demand each person puts on the Earth’s biosphere

  • It forms a part of a person’s carbon footprint

  • Ecological footprints are hugely uneven around the world

    • Much higher in developed countries - USA 15.5 gha per person

    • In developing countries they are lower - Haiti 0.7gha per person

• As global demand for resources increases, so the planet’s ecological footprint gets bigger and its carrying capacity gets smaller

• Calculations suggest the world is in a state of overshoot, using the equivalent of 1.6 Earth’s worth of resources

• With population predicted to increase to around 9-10 billion by 2050 even more ‘Earths’ will be required unless more sustainable resource use strategies are put in place

  • This may act as a natural ‘check’ on global population growth 

• Other implications of changes to the carrying capacity and ecological footprint include:

  • Destruction of ecosystems such as forests and coral reefs with knock-on effects of extinction of plant and animal species 

  • Climate change

  • Deforestation and changes of land use for growing urban areas, transport and industrial development

  • Reduction of availability and quality of fresh water

  • Reduction in soil quality through erosion leading to crop and food shortages