Externalities CHAPTER9 C H A P T E R C H E C K L I S T When you have completed your study of this chapter, you will be able to 1 Explain why negative externalities lead to inefficient overproduction and how property rights, pollution charges, and taxes can achieve a more efficient outcome. 2 Explain why positive externalities lead to inefficient underproduction and how public provision, subsidies, vouchers, and patents can achieve a more efficient outcome. 1
EXTERNALITIES IN OUR DAILY LIVES An externality is a cost or a benefit that arises from: Production that falls on someone other than the producer Consumption that falls on someone other than the consumer A negative externality is a production or consumption activity that creates an external cost. A positive externality is a production or consumption activity that creates an external benefit. EXTERNALITIES IN IN OUR DAILY LIVES Four types of externalities: Negative production externalities Positive production externalities Negative consumption externalities Positive consumption externalities EXTERNALITIES IN IN OUR DAILY LIVES Negative Production Externalities Pollution is the major example of this type of externality. Others are noise and congestion. Positive Production Externalities Example: Orchards provide positive production externalities to honey producers, who in turn provide positive production externalities to orchards. 2
EXTERNALITIES IN IN OUR DAILY LIVES Negative Consumption Externalities Smoking tobacco in a confined space Noisy parties Positive Consumption Externalities A flu vaccination Restoration of an historic building Education and research Private Costs and Social Costs Marginal private cost is the cost of producing an additional unit of a good or service that is borne by the producer of that good or service. Marginal external cost is the cost of producing an additional unit of a good or service that falls on people other than the producer. Marginal social cost is the marginal cost incurred by the entire society by the producer and by everyone else on whom the cost falls. Marginal social cost (MSC) is the sum of marginal private cost (MC) and marginal external cost. MSC = MC + Marginal external cost 3
Figure 9.1 shows the relationship between cost and output. When output is 4,000 tons of chemicals a month: 1. Marginal private cost is $100 a ton. 2. Marginal external cost is $125 a ton. 3. Marginal social cost is $225 a ton. Production and Pollution: How Much? When an industry is unregulated, the amount of pollution it creates depends on the market equilibrium price and the quantity of the good produced. If the industry creates an external cost, the market equilibrium is inefficient. Too much of the good is produced. Figure 9.2 shows inefficiency with an external cost. 1. The market is in equilibrium at a price of $100 a ton and 4,000 tons of chemical a month is inefficient. 2. Marginal social cost exceeds... 3. Marginal benefit. 4
4. The efficient quantity is 2,000 tons of chemical, where marginal social cost equals marginal benefit. 5. The gray triangle shows the deadweight loss created by the pollution externality. Property Rights Property rights are legally established titles to the ownership, use, and disposal of factors of production and goods and services that are enforceable in the courts. Figure 9.3 shows how property rights achieve an efficient outcome. 1. With property rights, the MC curve that excludes the cost of pollution shows only part of the producers marginal cost. 5
2. The marginal private cost curve includes the cost of pollution, and the supply curve is S = MC. 3. Market equilibrium is at a price of $150 a ton and a quantity of 2,000 tons of chemical a month and is efficient because 4. Marginal social cost equals marginal benefit. The Coase Theorem Coase theorem is the proposition that if property rights exist, only a small number of parties are involved, and transactions costs are low, then private transactions are efficient and the outcome is not affected by who is assigned the property right. Transactions costs are the opportunity costs of conducting a transaction. 6
Application of the Coase Theorem If factories own homes and river, the rent people willingly pay decreases as the amount of pollution increases. If homeowners own the river, factories must pay homeowners for any pollution, and the more they pollute, the more they pay. Regardless of who owns the river, so long as someone owns it, the factories bear the cost of pollution, and the quantity of production and pollution are efficient. Government Actions in the Face of External Costs The three main methods that governments can use to achieve a more efficient allocation of resources in the presence of external costs are: Emission charges Marketable permits Taxes Emission Charges Emission charges confront the producers with the external cost of pollution and provide an incentive to seek technologies that are less polluting. To work out the emission charge that achieves efficiency, the regulator needs a lot of information about the industry, which is generally not available. 7
Marketable Permits A marketable permit assigns to each producer in an industry an emission limit. Producers can buy and sell permits in the market. Producers with a low marginal cost of reducing pollution will sell permits and producers with a high marginal cost of reducing pollution will buy. Producers will buy and sell permits until their marginal cost of pollution equals the market price of a permit. Taxes Figure 9.4 shows the effects of a pollution tax. 1. A pollution tax is imposed that is equal to the marginal external cost arising from pollution. The supply curve becomes the marginal private cost curve, MC, plus the tax the curve labeled S = MC + tax. Because the tax equals the marginal external cost, the MSC curve becomes the supply curve. 8
2. Market equilibrium at a price of $150 a ton and 2,000 tons of chemical a month is efficient because 3. Marginal social cost equals marginal benefit. 4. The government collects tax revenue shown by the purple rectangle. Private Benefits and Social Benefits Marginal private benefit is the benefit of an additional unit of a good or service that the consumer of that good or service receives. Marginal external benefit is the benefit of an additional unit of a good or service that people other than the consumer of the good or service enjoy. 9
Marginal social benefit is the marginal benefit enjoyed by society by the consumers of a good or service and by everyone else who benefits from it. Marginal social benefit (MSB) is the sum of marginal private benefit (MB) and marginal external benefit. MSB = MB + Marginal external benefit Figure 9.5 shows an external benefit. When 15 million students attend college: 1. Marginal private benefit is $10,000 per student. 2. Marginal external benefit is $15,000 per student. 3. Marginal social benefit is $25,000 per student. Figure 9.6 shows inefficiency with an external benefit. 1. Market equilibrium is at a tuition of $15,000 a year and 7.5 million students and is inefficient because 2. Marginal social benefit exceeds 3. Marginal cost. 10
4. The efficient number of students is 15 million. 5. The gray triangle shows the deadweight loss created because too few students enroll in college. Government Actions In the Face of External Benefits Four devices that governments can use to achieve a more efficient allocation of resources in the presence of external benefits: Public provision Private subsidies Vouchers Patents and copyrights Public provision is the production of a good or service by a public authority that receives the bulk of its revenue from the government. A subsidy is a payment that the government makes to private producers to cover part of the costs of production. A voucher is a token that the government provides to households that can be used to buy specified goods or services. 11
Public provision Figure 9.7(a) shows how public provision can achieve an efficient outcome. 1. Marginal social benefit equals marginal cost with 15 million students enrolled in college. 2. The efficient quantity. 3. Tuition is $10,000 per year. 4. The taxpayers cover the remaining $15,000 of marginal cost per student. Private Subsidies Figure 9.7(b) shows how a subsidy achieves an efficient outcome of 15 million students. 1. A $15,000 subsidy per student shifts the supply curve to S = MC subsidy. 2. The dollar price is $10,000 a student. 3. The market equilibrium is efficient with 15 million students enrolled in college. 4. Marginal social benefit equals marginal cost. 12
Vouchers Figure 9.8 shows how vouchers can achieve an efficient outcome. The MSB curve becomes the demand curve because 1. With vouchers, buyers are willing to pay MB plus the value of the voucher. 2. Market equilibrium is efficient with 15 million students enrolled. 3. Price, marginal social benefit, and marginal cost are equal. 4. Tuition equals the dollar price of $10,000 plus the value of the voucher. Intellectual property rights are the property rights of the creators of knowledge and other discoveries. A patent or copyright is a government-sanctioned exclusive right granted to the inventor of a good, service, or productive process to produce, use, and sell the invention for a given number of years. 13