Chapter 10
Externalities
Market Failure
Market failure is when the free market does not provide the best outcome for society.
Monopoly is a form of market failureMarket failure also comes from
externalities and public goodsThis chapter is about externalities; the
next chapter is about public goods.
What are Externalities?
Benefits or costs that are not considered by market buyers and sellers because they are not reflected in the relevant prices.
Positive vs. Negative Externalities
There are two types: positive and negative externalities.
A negative externality means that a cost is imposed on a third party (they didn’t take part in the transaction).
A positive externality means that a benefit is enjoyed by a third party (they didn’t take part in the transaction).
Externalities are Market Failure
An important point: Both negative and positive externalities represent market failure. (As we go through some examples later, you’ll see why).
This happens because of a lack of economic efficiency.
When does Economic Efficiency exist?
Efficiency exists when the price to consumers, reflecting marginal benefit, equals marginal cost; in other words, when a completely voluntary exchange between two parties creates no THIRD PARTY EFFECTS (No cost or benefit to a third party).
Negative Externalities
Air pollution is the classic example of a negative externality.
Say a tire factory produces air pollution. The factory doesn’t pay anything because of
the pollution. A cost is imposed on the surrounding
community (dirty air) even though some of those people don’t work at the factory or use the tires.
A Negative Externality is Market Failure
Since the factory doesn’t pay for the pollution it causes, the marginal social cost of the tires is larger from the firm’s private marginal costs.
Private marginal costs are paid by the producer.
The social marginal cost includes the cost to society from the externality.
A Negative Externality is Market Failure 2
Social welfare is maximized when marginal social benefit equals marginal social cost.
Social benefit means the sum of benefits to everyone, including both private benefits and external benefits.
Will the tire factory maximize social welfare?
A Negative Externality is Market Failure 3
The answer is no, the tire factory won’t maximize social welfare. Why not?
It will produce the amount of tires that maximizes profits, where MR=MC (but MC is just private, not social marginal costs).
What happens when External Costs are Ignored?Since the firm will not pay the cost of the
pollution, it will produce “too many” tires and cause too much pollution.
“Too many” tires does not mean a surplus.
A Graphical Representation
The following graphs show the short-run marginal cost curves and the long-run average cost curves for two firms; one pays private costs (typical) and the other pays both private and external costs (politically correct firm).
13
Private MC
P
Q
Social MC
QS QP
D
Why don’t the firms take care of this themselves, and just produce less tires OR produce the tires in a way the causes less pollution, if that’s possible?
They wouldn’t make as much money.
15
Private ATC
Long-run Average CostP
Q
Social ATC
PLR=LRPAC
QLR
How can the market failure be corrected?
One traditional way is to depend on the government.
The idea is that Government can step in and (somehow) take corrective action;
--which usually means imposing a tax or passing regulations. Passing a tax equal to the cost of the pollution per tire internalizes the externality.
17
D
Using an Effluent Tax to Achieve Environmental EfficiencyP
Q
Social MC
Private MC
QS QC
PS
PC
tax
Results of Effluent Tax
Firm will produce less tires.The price of tires will go upIs this “fair”?Actually it is, because it’s the consumers’
“fault” that the tires are being produced.
What about Government Failure?
Government can fail, too. It might regulate too much, or make the taxes too high.
The government has an incentive to overestimate the tax because it gets the money!
Is the Efficient amount of Pollution typically Zero?No, the marginal social cost
of achieving one more unit of clean air is greater than the marginal social benefit
We would have to change everything to have zero pollution.
Emissions Auctions and Trading
Government-run auction that that allows firms to buy and sell the right to pollute. The price is determined by the free market.
Positive Externalities
A third-party receives a benefit even though they didn’t pay for it.
The marginal social benefit exceeds the private marginal cost. Therefore the good will be underproduced by
the free market There’s Market failure.
Positive Externalities 2
VaccinationsProperty ImprovementEducation
Coase Theorem
Coase wanted to explain why negative externalities occur.
It’s because of a lack of property rights.If you could own the air, air pollution would
not be an externality.
Coase Theorem 2
If property rights are well-defined and enforced, and transaction costs are low, the free market take care of any externalities.
Consider a lake with a factory on one side and a house on the other. If someone owns the lake, the free market will
make sure no externality exists.
Transaction Costs
The costs of negotiating and enforcing a contract
2 Interpretations of Coase Theorem
The free market (individualist) view:The vast majority of environmental problems
qualify for Coase Theorem solutions. The statist (big government) view:Only a small number of environmental
problems qualify for Coase Theorem solutions.
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