marginal social benefit of pollution - worth publishers污染值得出版社会边际收益

What externalities are and why they can lead to inefficiency in a market economy and support for government interventionThe difference between negative, positive, and network externalities The importance of the Coase theorem, which explains how private individuals can sometimes solve externalities Why some government policies to deal with externalitiessuch as emissions taxes, tradable permits, or Pigouvian subsidiesare efficient, although others, like environmental standards, are inefficient,How positive externalities give rise to arguments for industrial policyWhy network externalities are an important feature of high-tech industries,The Economics of Pollution,Pollution is a bad thing. Yet most pollution is a side effect of activities that provide us with good things.Pollution is a side effect of useful activities, so the optimal quantity of pollution isnt zero. Then, how much pollution should a society have? What are the costs and benefits of pollution?,Costs and Benefits of Pollution,The marginal social cost of pollution is the additional cost imposed on society as a whole by an additional unit of pollution.The marginal social benefit of pollution is the additional gain to society as a whole from an additional unit of pollution.The socially optimal quantity of pollution is the quantity of pollution that society would choose if all the costs and benefits of pollution were fully accounted for.,The Socially Optimal Quantity of Pollution,Marginal social cost, marginal social benefit,Quantity of pollution,emissions (tons),Q,OPT,0,$200,Marginal social cost, MSC, of pollution,O,Socially optimal quantity of pollution,Socially optimal point,Marginal social benefit, MSB, of pollution,Pollution: An External Cost,An external cost is an uncompensated cost that an individual or firm imposes on others.An external benefit is a benefit that an individual or firm confers on others without receiving compensation.,Pollution: An External Cost,Pollution is an example of an external cost, or negative externality; in contrast, some activities can give rise to external benefits, or positive externalities. External costs and benefits are known as externalities.Left to itself, a market economy will typically generate too much pollution because polluters have no incentive to take into account the costs they impose on others.,Why a Market Economy Produces Too Much Pollution,Q,M,K,T,Q,H,Q,OPT,0,$400,300,200,100,O,Marginal social benefit at QMKT,Market-determined quantity of pollution,MSC of pollution,MSB of pollution,The market outcome is inefficient: marginal social cost of pollution exceeds marginal social benefit,Marginal social cost, marginal social benefit,Quantity of pollution,emissions (tons),Socially optimal quantity of pollution,Optimal Pigouvian tax on pollution,Marginal social cost at QMKT,Private Solutions to Externalities,In an influential 1960 article, the economist Ronald Coase pointed out that, in an ideal world, the private sector could indeed deal with all externalities. According to the Coase theorem, even in the presence of externalities an economy can always reach an efficient solution provided that the transaction coststhe costs to individuals of making a dealare sufficiently low. The costs of making a deal are known as transaction costs.,Private Solutions to Externalities,The implication of Coases analysis is that externalities need not lead to inefficiency because individuals have an incentive to find a way to make mutually beneficial deals that lead them to take externalities into account when making decisions.When individuals do take externalities into account, economists say that they internalize the externality.Why cant individuals always internalize externalities?Transaction costs prevent individuals from making efficient deals.,Private Solutions to Externalities,Examples of transaction costs include the following:The costs of communication among the interested partiescosts that may be very high if many people are involved.The costs of making legally binding agreements that may be high if doing so requires the employment of expensive legal services.Costly delays involved in bargainingeven if there is a potentially beneficial deal, both sides may hold out in an effort to extract more favorable terms, leading to increased effort and forgone utility.,Policies Toward Pollution,Environmental standards are rules that protect the environment by specifying actions by producers and consumers. Generally such standards are inefficient because they are inflexible.An emissions tax is a tax that depends on the amount of pollution a firm produces.Tradable emissions permits are licenses to emit limited quantities of pollutants that can be bought and sold by polluters.Taxes designed to reduce external costs are known as Pigouvian taxes.,Environmental Standards Versus Emissions Taxes,(b) Emissions Taxes,(a) Environmental Standard,0,600,400,200,$600,200,0,600,300,$600,150,300,MB,B,MB,B,MB,A,MB,A,T,A,S,A,S,B,T,B,Emissions,tax,Environmental standards forces both plants to cut emission by half,Without government action, each plant emits 600 tons.,Marginal benefit to individual polluter,Marginal benefit to individual polluter,Quantity of pollution emissions (tons),Quantity of pollution emissions (tons),Plant A has a lower marginal benefit of pollution and reduces emissions by 400 tons,Plant B has a higher marginal benefit of pollution and reduces emissions by only 200 tons,Policies Toward Pollution,When the quantity of pollution emitted can be directly observed and controlled, environmental goals can be achieved efficiently in two ways: emissions taxes and tradable emissions permits.These methods are efficient because they are flexible, allocating more pollution reduction to those who can do it more cheaply.An emissions tax is a form of Pigouvian tax, a tax designed to reduce external costs. The optimal Pigouvian tax is equal to the marginal social cost of pollution at the socially optimal quantity of pollution.,Production, Consumption, and Externalities,When there are external costs, the marginal social cost of a good or activity exceeds the industrys marginal cost of producing the good. In the absence of government intervention, the industry typically produces too much of the good.The socially optimal quantity can be achieved by an optimal Pigouvian tax, equal to the marginal external cost, or by a system of tradable production permits.,Positive Externalities and Consumption,S,D,MSB of flu shots,O,(a) Positive Externality,Price of flu shot,Q,OPT,P,OPT,P,MSB,P,M,K,T,Q,M,K,T,S,D,O,Quantity of flu shots,Q,OPT,Q,M,K,T,(b) Optimal Pigouvian Subsidy,E,MKT,E,M,K,T,Price, marginal social benefit of flu shot,Price to producers after subsidy,Optimal Pigouvian subsidy,Price to consumers after subsidy,Marginal external benefit,Quantity of flu shots,Private Versus Social Benefits,The marginal social benefit of a good or activity is equal to the marginal benefit that accrues to consumers plus its marginal external benefit.,Private Versus Social Benefits,A Pigouvian subsidy is a payment designed to encourage activities that yield external benefits.A technology spillover is an external benefit that results when knowledge spreads among individuals and firms. The socially optimal quantity can be achieved by an optimal Pigouvian subsidy equal to the marginal external benefit.An industrial policy is a policy that supports industries believed to yield positive externalities.,Private Versus Social Costs,The marginal social cost of a good or activity is equal to the marginal cost of production plus its marginal external cost.,Negative Externalities and Production,MSC of livestock,S,D,Q,OPT,MKT,P,Q,S,D,Q,OPT,Q,E,E,O,O,(a) Negative Externality,(b) Optimal Pigouvian Subsidy,Price of livestock,Quantity of livestock,Price, marginal social cost of livestock,Quantity of livestock,Marginal external cost,Price to consumers after tax,Optimal Pigouvian subsidy,Price to producers after tax,MKT,MKT,MKT,MKT,Network Externalities,A good is subject to a network externality when the value of the good to an individual is greater when a large number of other people also use the good.,Network Externalities,Any way in which other peoples consumption of a good increases your own marginal benefit from consumption of that good can give rise to network effects.,Network Externalities,A good is subject to positive feedback when success breeds greater success and failure breeds failure.,When pollution can be directly observed and controlled, government policies should be geared directly to producing the socially optimal quantity of pollution, the quantity at which the marginal social cost of pollution is equal to the marginal social benefit of pollution. The costs to society of pollution are an example of an external cost; in some cases, however, economic activities yield external benefits. External costs and benefits are jointly known as externalities, with external costs called negative externalities and external benefits called positive externalities.,According to the Coase theorem, individuals can find a way to internalize the externality, making government intervention unnecessary, as long as transaction coststhe costs of making a dealare sufficiently low.Governments often deal with pollution by imposing environmental standards, a method, economists argue, that is usually an inefficient way to reduce pollution. Two efficient (cost-minimizing) methods for reducing pollution are emissions taxes, a form of Pigouvian tax, and tradable emissions permits. The optimal Pigouvian tax on pollution is equal to its marginal social cost at the socially optimal quantity of pollution.,5. When a good or activity yields external benefits, such as technology spillovers, the marginal social benefit of the good or activity is equal to the marginal benefit accruing to consumers plus its marginal external benefit. Without government intervention, the market produces too little of the good or activity. An optimal Pigouvian subsidy to producers, equal to the marginal external benefit, moves the market to the socially optimal quantity of production. This yields higher output and a higher price to producers. It is a form of industrial policy, a policy to support industries that are believed to generate positive externalities.,6. When only the original good or activity can be controlled, government policies a