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Externalities. Chapter 10. EXTERNALITIES. An externality is the uncompensated impact of one person’s actions on another person Both positive & negative externalities exist Externalities cause markets to be inefficient That is, markets do not maximize total surplus.
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Externalities Chapter 10
EXTERNALITIES • An externalityis the uncompensated impact of one person’s actions on another person • Both positive & negative externalities exist • Externalities cause markets to be inefficient • That is, markets do not maximize total surplus
Negative Externalities • Automobile exhaust • Cigarette smoking • Barking dogs (loud pets) • Loud stereos in an apartment building • Noisy Students • Neighbor’s poorly maintained property
Positive Externalties • Immunizations • Restored historic buildings • Research into new technologies • Neighbor’s well maintained property
MC = MB MARKET INEFFICIENCY • Negative externalities lead markets to overproduce • Positive externalities lead markets to under-produce
Supply = MCP External social Cost (private cost) Optimum Spillover Cost Equilibrium MC = MB Demand = MBP (private value) QOPTIMUM QMARKET Negative Externality: Pollution MCT= MCP + MCS Price of Aluminum Quantity of 0 Aluminum
External social benefit Supply = MCP (private cost) Optimum Equilibrium Spillover Benefits Demand = MBP (private value) QOPTIMUM QMARKET Positive Externality: Neighbor paints House Price MBT = MBP + MBS Quantity 0
Solutions to Externalities • Internalizing an externality involves altering incentives • Government Methods • Taxes (corrective taxes) • Subsidies • Patents • Laws (immunization laws, pollution laws) • Free market solution: • Trading pollution credits
Taxing Negative Externalities Impose Tax = spillover cost Shifts Supply Curve left Reach social optimal output Total Cost = Total Benefit Total Cost = MCP + MCS
Subsidizing Positive Externalities Impose Subsidy=spillover benefit Shifts demand curve right Reach social optimal output Total Cost = Total Benefit
Worksheet • Externalities