Loss of Biosphere Integrity (HL) (DP IB Environmental Systems & Societies (ESS))

Loss of Biosphere Integrity

What is biosphere integrity?

• Biosphere integrity refers to the health and stability of the Earth's biodiversity, including it ecosystems, habitats, species, and genetic diversity

  • It is one of the nine planetary boundaries

  • These are thresholds that define a safe operating space for humanity

  • Crossing these boundaries increases the risk of environmental change that could destabilise the Earth system

• The loss of biosphere integrity shows that human activities have caused a rapid decline in biodiversity, pushing species extinction rates beyond the natural threshold

  • Scientists believe this boundary has already been crossed

  • This means that species extinctions are happening at a significantly faster rate than in the past

• Species extinction is occurring 100 to 1000 times faster than the background extinction rate

  • Often called the sixth mass extinction, and is driven by human activities such as deforestation, pollution, climate change, and habitat destruction

Awaiting image: Extinction rates

Image caption: Vertebrate species extinction rates since 1500

• When species are lost, it doesn’t just affect individual ecosystems

  • It can also destabilise the whole Earth system, leading to widespread changes that affect the climate, air, water, and food resources

Tipping points in the Earth system

• Tipping points are critical thresholds where small changes in the environment can lead to drastic and irreversible consequences

  • The loss of key species or ecosystems can create feedback loops that push the Earth system into a new, less stable state

• If the loss of biodiversity continues, it could lead to widespread ecosystem collapse

  • For example, the disappearance of pollinators like bees could disrupt global food production

    • This will also impact wild flower populations globally

  • Forest degradation can reduce carbon storage, accelerating climate change by releasing more carbon dioxide into the atmosphere

    • Large-scale deforestation could push the Amazon past a tipping point where it no longer functions as a rainforest

  • The loss of phytoplankton due to warming oceans and ocean acidification could lead to a major disruption of the marine food chain

    • This could eventually lead to collapse in marine biodiversity and significantly impact the ocean's ability to sequester carbon, affecting global climate systems

  • Climate change is causing the melting of Arctic sea ice

    • This loss of habitat is threatening species like polar bears

    • The resulting sea-level rise is also leading to the destruction of previously biodiverse coastal habitats

    • The loss of ice reduces Earth's ability to reflect sunlight, causing even more heat to be absorbed

• There is concern that the loss of species and ecosystems could reach a point where the entire Earth system begins to change in unpredictable ways, possibly affecting many factors, including:

  • Climate stability

  • Food security

  • Freshwater availability

Ecosystem services

• Ecosystem services are the benefits that humans receive from nature, including clean air, water, food, and climate regulation

  • The loss of biosphere integrity threatens these services, making it harder for ecosystems to provide essential resources for expanding human populations