IBEnvironmental Systems & Societies (ESS)DPSLRevision Notes3. Biodiversity & Conservation3.2 Human Impact on BiodiversityTragedy of the Commons

Tragedy of the Commons (DP IB Environmental Systems & Societies (ESS))

Revision Note

Alistair Marjot

Expertise

Biology & Environmental Systems and Societies

Tragedy of the Commons

  • The tragedy of the commons describes the overuse and depletion of a shared resource

    • It occurs when individuals act in their own self-interest rather than considering the common good

    • It leads to the degradation of the resource, making it unavailable for future use

Diagram of the tragedy of the commons for IB Environmental Systems and Societies
A non-human example demonstrating the tragedy of the commons

Implications for sustainability

  • Overexploitation:

    • Many natural resources are used faster than they can be replenished

    • This is resulting in resource depletion and could eventually lead to the collapse of certain ecosystems

  • Impact on biodiversity:

    • Result in the loss of habitats and species

    • It can also lead to reduced genetic diversity

      • These factors can weaken ecosystem resilience, threatening biodiversity

Case Study

Overfishing of Fish Stocks on the Grand Banks

  • Location:

    • Grand Banks, off the coast of Newfoundland, Canada

  • Natural resource affected:

    • Cod fish

  • Problem:

    • Intensive fishing by local and international fleets

    • Advanced fishing technologies and no effective regulation

  • Consequences:

    • Dramatic decline in cod populations

    • Economic collapse of the fishing industry in the region

    • Long-term ecological damage

  • Current situation:

    • Strict regulations and moratoriums on cod fishing

    • Slow recovery of cod stocks but these are still a long way below historical levels

  • The tragedy of the commons does not only apply to situations where a natural resource is overharvested

    • It also applies to the contamination and degradation of ecosystems by humans

Case Study

Plastic Pollution in Ocean Gyres

  • Location:

    • Various ocean gyres, including the North Pacific Gyre, home to the Great Pacific Garbage Patch

  • Natural resource affected:

    • Marine environment and marine biodiversity

  • Problem:

    • Accumulation of plastic debris from land-based and marine sources

    • Plastics are non-biodegradable and persist for hundreds of years

  • Consequences:

    • Marine animals ingest plastics, leading to injury and death

    • Plastics break down into microplastics, entering the food chain

    • Damage to marine ecosystems and decline in marine biodiversity

  • Current situation:

    • Efforts to reduce plastic use and increase recycling

    • International agreements and clean-up initiatives

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Alistair Marjot

Author: Alistair Marjot

Alistair graduated from Oxford University with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems & Societies. Alistair has continued to pursue his interests in ecology and environmental science, recently gaining an MSc in Wildlife Biology & Conservation with Edinburgh Napier University.