Bài giảng Economics - Chapter 19 The Environment

Chapter 19The EnvironmentChapter OutlineHOW CLEAN IS CLEAN ENOUGH?THE EXTERNALITIES APPROACHTHE PROPERTY RIGHTS APPROACHENVIRONMENTAL PROBLEMS AND THEIR ECONOMIC SOLUTIONSHow Clean is Clean EnoughEconomists answer most “how much is enough” questions with the same answer: “until the marginal benefit equals the marginal cost.”The right level of environmental cleanliness is achieved when the value of cleaning the environment a little more equals the cost of doing so.The Dirty Room ExampleCleaning your room (dorm room or your own bedroom) can be done to many degreesA short time can be spent getting things off the floor (high marginal benefit, low marginal cost).More time can be spent with vacuuming and straightening (moderate marginal benefit, moderate marginal cost).Even more time can be spent deep cleaning, removing stains from carpets, dusting all shelves and moving furniture so as to clean behind them (for most low marginal benefit and high marginal cost.)Modeling Environmental CleanupMarginal BenefitMarginal CostEnvironmental QualityMarginal Cost Marginal BenefitEQ*The Externalities ApproachExternalities are the effects of a transaction that hurt or help people who are not a part of that transaction.When a product affects someone other than the consumer of producer in a negative way, such as pollution, economists suggest that the market has failed.When the Market Works for EveryoneSupplyDemandQ*P*PQ/tABC0Value to the Consumer: 0ACQ*Consumers Pay Producers: OP*CQ*The Variable Cost to Producers: OBCQ*Consumer Surplus: P*ACProducer Surplus: BP*CWhen Externalities are PresentIf there are externalities then there is overproduction of a good.The total cost of a good to society (called social cost) includes the costs of production incurred by the firm as well as the external costs.When the Market Does Not Work for EveryoneSMarginal CostD(Marginal Benefit)Q*P*PQ/t0Social CostExternal CostQ’P’The Property Rights ApproachCoase’s TheoremIf there are no costs of bargaining between people and polluters then by assigning a property right (either the right of the firm to pollute or the right of people to be free from pollution) people and firms can negotiate to the correct level of production.Why Coase’s Theorem Makes SensePeople do not pollute up their own private property nearly as much as they pollute Common Property. Common Property is not owned by any individual but is owned by government or has some other collective ownership property.This is because when they do they are removing value from themselves.Problems with Coase’s TheoremIt is impossible for companies to negotiate with millions of citizens affected by their pollution.The system picks a winner and a loser when it establishes the property right.Various Environmental Problems and their SolutionsProblems of Water pollution, Air Pollution, Extinction of Species, Acid Rain, Global WarmingLegal SolutionsClean Water ActClean Air ActEndangered Species ActLegal vs. Economic SolutionsLegal solutions to environment problems typically limit or make illegal activities that harm the environment.Economic solutions to environmental problems tend to discourage activities that harm the environment by making the people doing the harm recognize the cost of that harm.Taxation as an Economic SolutionSMarginal CostD(Marginal Benefit)Q*P*PQ/t0S+taxtaxQ’P’Other Economic SolutionsEmission permits for SO2 in the Clean Air Act of 1990. California’s old-car purchases