4.7 Sustainable Development

The estuary is rivalrous: one fisher's catch reduces what remains for others. It is also non-excludable: there is no mechanism to stop any individual from fishing there. A resource with both these properties is a common pool resource.

Because each fisher cannot be excluded and each fish caught by one reduces the stock available to others, every individual has a rational incentive to fish as hard as possible before competitors do. This collectively drives the stock toward depletion — the classic tragedy of the commons.

The free-rider problem applies to public goods (non-excludable AND non-rivalrous). Here the resource IS rivalrous — one fisher's catch leaves less for others — so it is not a public good, and the free-rider label is not the most precise fit.

The scenario matches the tragedy of the commons: a rivalrous, non-excludable common pool resource subject to overexploitation because individual incentives conflict with the collective long-run interest.

The question asks which concept most precisely describes a shared fishery where each user over-exploits because others will take what they leave behind.

A public good is non-rivalrous as well as non-excludable. Fish are rivalrous — one caught is gone — so the estuary is not a public good. This option misclassifies the resource type.

Imperfect information would mean fishers don't know the stock size. The question says they knowingly fish before others do — this is a strategic incentive problem, not an information problem.

While overfishing does impose external costs, the question asks for the concept that describes the structural incentive problem in managing the shared resource, which is the tragedy of the commons rather than the externality concept.

'The tragedy of the commons arising from a common pool resource being rivalrous but non-excludable' precisely identifies both the resource type and the mechanism driving overexploitation.

Scarcity is the fundamental economic condition that arises because human wants are effectively unlimited while available resources — land, labour, capital, natural resources — are finite. It is permanent and universal: it exists even when markets clear perfectly.

A shortage is a temporary market condition in which quantity demanded exceeds quantity supplied at the prevailing price. It is resolved when prices rise, which reduces quantity demanded and/or increases quantity supplied, restoring market equilibrium.

Sustainable development responds to scarcity as a long-run structural problem: because resources are finite, choices made today about resource use impose an opportunity cost on future generations. Shortages, being temporary, do not raise this intergenerational issue.

The correct option captures both parts of the distinction: scarcity is permanent (finite resources vs. unlimited wants) while shortage is temporary (a price-correctable imbalance), making scarcity — not shortage — the basis for sustainable development.

The question asks which statement correctly distinguishes scarcity (a permanent structural condition) from a shortage (a temporary market disequilibrium).

'Scarcity describes quantity demanded exceeding quantity supplied' — this is precisely the definition of a shortage, not scarcity. This option has the two concepts backwards.

Scarcity is universal: it applies in rich and poor economies alike because wants always exceed finite resources regardless of income level. Restricting scarcity to developing economies misrepresents the concept.

Scarcity exists even in perfectly competitive, well-functioning markets. It is not caused by market failure; it is the underlying reason all economics — and all allocation decisions — are necessary.

The option stating that scarcity is permanent (finite resources vs. unlimited wants) while shortage is a temporary price-correctable imbalance is precisely correct and matches standard economic definitions.