A common pool resource has two features. Together they mean it gets used up.
Why it is overused
Rivalrous
Every fish one boat catches is one fewer for the others.
Non-excludable
Nobody can be stopped from fishing in the open sea.
So: used up
Each user takes as much as they can before others do.
The points to remember
- Definition for 2 marks: non-excludable AND rivalrous.
- Examples: fish stocks, forests, groundwater, clean air.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
Overuse is a negative externality: each user ignores the cost to others and to the future.
Our example (made-up numbers)
| Market | Sustainable | |
|---|---|---|
| Catch a year | 40 | 20 |
| Cost to others per tonne | €4 (ignored) | counted |
Animated graph
Watch the graph build step by step in study mode.
Remember it as: Free to use, so used up: the tragedy of the commons.
Learn what examiners really want
See exactly what to write to score full marks. Our AI shows you model answers and the key phrases examiners look for.
There is no single owner to protect the resource, so someone must set limits.
Ways to protect a common resource
Quotas and rules
Catch limits, protected areas, bans on certain nets.
Tradable quotas or permits
Cap total use; users buy and sell the right to use it.
Taxes and fees
Charge for each unit used, so users pay part of the cost.
Collective self-governance
Users agree and enforce their own rules, as many fishing villages do.
International agreements
For the oceans and the air, countries must act together.
The specimen Paper 1 asked this, as part (b) for 15 marks; Paper 3 (November 2023) asked why collective self-governance can work.
Using real-world examples, evaluate different approaches to managing common access resources.
Model answer plan
See the answer broken into clear points, with guidance on how each point earns marks.
Animated graph
Watch the graph build step by step in study mode.
What the diagram must show
- Axes: costs and benefits, Q of the resource used; MPB = MSB, MPC, MSC above MPC.
- Qm (overuse) above Qopt (sustainable); the welfare loss.
How the 15 marks are given
| Marks | What your answer needs |
|---|---|
| 13–15 | Theory fully explained, terms right all the way through, balanced evaluation, real examples fully developed to support the argument |
| 10–12 | Theory explained, terms mostly right, evaluation mostly balanced, real examples developed |
| 7–9 | Theory partly explained, some evaluation but one-sided, examples partly developed |
| 4–6 | Theory only described, evaluation superficial, examples only named |
| 1–3 | Theory stated but not relevant, no evaluation |