Population Growth & Environmental Stress (HL) (DP IB Environmental Systems & Societies (ESS))

Population Growth & Environmental Stress

Human population growth

• The global population is currently about 8.2 billion as of 2024

• Future projections:

  • By 2075, the global population is expected to reach around 10 billion

  • By 2125, estimates vary, but the global population could stabilise (level out) or slightly decline if fertility rates fall

• Factors influencing global population projections include:

  • Fertility rates: the average number of children per woman (this is falling in many developed countries)

  • Mortality rates: death rates can decrease with advances in healthcare

  • Urbanisation: urban living often correlates with lower birth rates

  • Government policies: population control measures or incentives can decrease or increase fertility rates

Environmental stress

• Environmental stress refers to the strain placed on Earth’s ecosystems due to human activity, such as pollution, deforestation, and resource depletion

• Link to global population growth:

  • More people require more resources (e.g. food, water, energy)

  • This leads to more overexploitation and environmental degradation

Disparity in biocapacity

• Biocapacity is the Earth’s ability to regenerate resources and absorb waste, such as carbon dioxide

  • A biocapacity deficit occurs when human demand exceeds the planet’s capacity to replenish resources

• Uneven biocapacity distribution:

  • Some countries (e.g. Sweden and Brazil) have a large biocapacity and can support increased population growth

  • Other countries (e.g. UAE and China) cannot support increased population growth and are already in a biocapacity deficit

    • These countries consume far more resources than their biocapacity can sustainably support

    • E.g. the USA has a large ecological footprint, using resources far beyond its biocapacity

  • These are often wealthier nations that rely on importing resources from poorer countries, increasing global inequality

    • E.g. many African nations have smaller ecological footprints but face resource exploitation by wealthier countries

Social foundations and planetary boundaries

Doughnut economics model

• The doughnut economics model aims to balance social needs with environmental limits

  • It provides a framework for ensuring that economic activity remains within the ecological limits of the planet whilst attempting to address social inequality and injustice at the same time

• Parts of the model:

  • The outer edge of the doughnut represents the planetary boundaries (environmental constraints)

  • The inner edge of the doughnut represents social foundations (basic human needs)

Social foundations

• The social foundations are the minimum standards for a good quality of life, such as access to food, water, healthcare, and education

• Crossing social foundations:

  • This occurs when people do not meet basic needs, leading to poverty and inequality

  • E.g. millions of people in Sub-Saharan Africa lack access to clean water and food security

Planetary boundaries

• The planetary boundaries (sometimes referred to as the ecological ceiling) are the limits on the Earth’s systems that should not be crossed to avoid damaging ecosystems, such as the climate, biodiversity, and oceans

• Crossing planetary boundaries:

  • This occurs when human activity exceeds the Earth’s safe limits, causing irreversible damage

  • E.g. the Amazon rainforest is nearing a tipping point due to deforestation