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M10.L03 — Government Solutions: Pigouvian Taxes and Subsidies

Module: Module 10 — Externalities and Market Failure Lesson: L03 of 05 Duration: ~30 minutes Level: Introductory Provenance: OpenStax Principles of Microeconomics 3e | Khan Academy Microeconomics

Learning Objective

Design Pigouvian taxes and subsidies to correct market failures caused by externalities.

Pigouvian Taxes and Subsidies

A Pigouvian tax is set equal to the marginal external cost of a negative externality (e.g., carbon tax on pollution). A Pigouvian subsidy equals the marginal external benefit of a positive externality (e.g., subsidies for renewable energy). These tools "internalize" externalities by aligning private and social costs/benefits.

Tradeable permits (like Australia's Safeguard Mechanism) are an alternative that caps total emissions while allowing market trading.

Worked Example

Calculating a Pigouvian Tax for Plastic Bag Use

  1. External Cost: Each plastic bag creates $0.10 in environmental harm.
  2. Tax: $0.10 per bag discourages overuse without banning it outright.
  3. Outcome: Consumers reduce usage to the socially optimal level.

Common Misconception

"Pigouvian taxes are just another way for governments to raise revenue."

The primary goal is to correct market failures, not generate revenue. Ideally, the tax revenue offsets external costs (e.g., funding clean-up programs).

Key Takeaways

  • Pigouvian taxes reduce negative externalities; subsidies encourage positive ones.
  • Taxes should equal marginal external cost at the efficient quantity.
  • Tradeable permits offer flexibility but require careful cap setting.
  • Command-and-control regulation (e.g., bans) is often less efficient than market-based solutions.

Practice

  1. Why is a carbon tax more efficient than a flat emissions limit?
  2. How would you set a subsidy for solar panel installation?
  3. Compare tradeable permits to Pigouvian taxes.

Further Resources

Provenance: OpenStax Principles of Microeconomics 3e | Khan Academy Microeconomics