IB DP Economics - Unit 2 - Government intervention in response to externalities and common pool resources-Study Notes - New Syllabus

Government Intervention in Response to Externalities and Common Pool Resources

Governments intervene in markets when externalities and common pool resources lead to market failure, where resources are not allocated efficiently.

Key Problem

• With externalities:
  • Market equilibrium occurs at:    

    \( \mathrm{MPB = MPC} \)

  • But social optimum is:
    

    \( \mathrm{MSB = MSC} \)

• This leads to:
  • Overproduction (negative externalities)
  • Underproduction (positive externalities)
• With common pool resources:
  • Overuse due to non-excludability
  • Leads to tragedy of the commons

Key Aim of Government Intervention

Move output from market equilibrium → socially optimal level

\( \mathrm{MSB = MSC} \)

How Governments Intervene

• To internalise externalities (make private agents consider social costs/benefits).
• To reduce overuse of common pool resources.
• To achieve allocative efficiency and maximise social welfare.

Types of Intervention

• Market-based policies (taxes, subsidies, permits)
• Regulatory policies (laws, quotas)
• Behavioural policies (nudges, education)
• Global cooperation (international agreements)

Government Intervention in Response to Externalities and Common Pool Resources

1. Indirect (Pigouvian) Taxes

Pigouvian taxes are taxes imposed on goods that generate negative externalities, equal to the external cost per unit.

Economic Explanation:

• Negative externalities mean:
  

  \( \mathrm{MSC > MPC} \)

• A tax increases firms’ costs, shifting the supply curve left.
• This reduces output from the market level to the socially optimal level where:
  

  \( \mathrm{MSB = MSC} \)

Tax → Internalise external cost → Reduce overproduction

Evaluation:

• Difficult to measure exact external cost.
• May reduce firm profitability.

2. Carbon Taxes

A carbon tax is a specific type of indirect tax imposed on activities that emit carbon dioxide (CO₂).

Economic Explanation:

• Targets climate change caused by emissions.
• Increases cost of polluting activities.
• Encourages firms to:
  • Reduce emissions
  • Invest in cleaner technologies
• Reduces production of harmful goods.

Higher emissions cost → Lower pollution

Evaluation:

• May increase production costs and prices.
• Effectiveness depends on elasticity and global cooperation.

3. Legislation and Regulation

Legislation and regulation involve laws and rules that directly control economic activity.

Economic Explanation:

• Governments set limits on harmful behaviour (e.g. pollution caps).
• Firms must comply or face penalties.
• Directly reduces negative externalities without using price mechanisms.

Rules → Controlled production → Reduced external harm

Evaluation:

• Effective but may increase costs for firms.
• Requires monitoring and enforcement.

4. Education and Awareness Creation

Government provision of information campaigns to influence consumer and producer behaviour.

Economic Explanation:

• Addresses information failure.
• Helps consumers understand true social costs and benefits.
• Encourages reduction in consumption of demerit goods and increase in merit goods.
• Shifts demand toward socially optimal level.

Better information → Better decisions → Reduced market failure

Evaluation:

• Low cost and non-intrusive.
• Effect may be slow or limited.

5. Tradable Permits (Cap and Trade)

A system where the government sets a limit (cap) on total pollution and issues permits that can be bought and sold.

Economic Explanation:

• Firms must hold permits to pollute.
• Firms that reduce emissions can sell excess permits.
• Creates a market-based incentive to reduce pollution.
• Ensures pollution stays within a fixed limit.

Cap → Limit pollution | Trade → Efficiency

Evaluation:

• Efficient and flexible.
• Difficult to set correct cap level.

6. International Agreements

Cooperation between countries to address global externalities such as climate change.

Economic Explanation:

• Many externalities are global in nature (e.g. carbon emissions).
• Individual countries may lack incentive to act alone.
• Agreements set targets and commitments for reduction.

Global problem → Collective action required

Evaluation:

• Difficult to enforce compliance.
• Free-rider problem may occur.

7. Collective Self-Governance

Collective self-governance occurs when users of a resource organise and manage it themselves without direct government control.

Economic Explanation:

• Users agree on rules and limits for resource use.
• Encourages cooperation and shared responsibility.
• Helps prevent the tragedy of the commons.
• Internalises external costs through community enforcement.

Community control → Sustainable use

Evaluation:

• Effective in small, local communities.
• Difficult to implement for large or global resources.

8. Subsidies

A subsidy is a payment by the government to producers or consumers to encourage production or consumption.

Economic Explanation:

• Used to correct positive externalities.
• Lowers production costs or prices.
• Shifts supply curve right.
• Increases output toward socially optimal level.

Subsidy → Lower price → Higher output

Evaluation:

• Improves welfare by increasing beneficial consumption.
• Leads to government expenditure.

9. Government Provision

Government provision involves the state directly supplying goods and services.

Economic Explanation:

• Used when markets fail to provide sufficient goods.
• Ensures provision of public goods and merit goods.
• Output is provided at or near the socially optimal level.

Government supply → Correct underprovision

Evaluation:

• Ensures access and equity.
• May lead to inefficiency and high costs.