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Course: Microeconomics > Unit 9
Lesson 2: Bonus articles: Pollution as a negative externality- The economics of pollution
- Command-and-control regulation
- What are market-oriented environmental tools?
- Types of market-oriented environmental tools
- The benefits and costs of US environmental laws
- International environmental issues
- The tradeoff between economic output and environmental protection
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The economics of pollution
Pollution is an example of a negative externality.
Key Points
- Economic production can cause environmental damage. This tradeoff arises for all countries, whether high-income or low-income, and whether their economies are market-oriented or command-oriented.
- An externality, sometimes called a spillover, occurs when an exchange between a buyer and seller has an impact on a third party who is not part of the exchange. Externalities can be positive or negative.
- Market failure is when the market does not allocate resources on its own efficiently in a way that balances social costs and benefits; externalities are one example of a market failure.
- Social costs are costs that include both the private costs incurred by firms and also additional external costs incurred by third parties outside the production process.
Pollution
From 1970 to 2012, the population of the United States increased by one-third and the size of the US economy more than doubled. Despite this growth, the United States, using a variety of anti-pollution policies, has made genuine progress against a number of pollutants.
According to the US Energy Information Administration, the emissions of certain key air pollutants declined substantially from 2007 to 2012; in fact, they dropped 730 million metric tons a year—a 12% reduction. This seems to indicate that progress has been made in the United States in reducing overall carbon dioxide emissions, which cause greenhouse gases.
Despite the gradual reduction in emissions from fossil fuels, many important environmental issues remain. Along with the still-high levels of air and water pollution, other issues include hazardous waste disposal, destruction of wetlands and other wildlife habitats, and the impact of pollution on human health.
Externalities
Private markets offer an efficient way to put buyers and sellers together and determine what goods are produced, how they are produced, and who gets them. The principle that voluntary exchange benefits both buyers and sellers is a fundamental building block of the economic way of thinking. But what happens when a voluntary exchange affects a third party who is neither the buyer nor the seller?
Consider, for example, a concert producer who wants to build an outdoor arena that will host country music concerts a half-mile from your neighborhood. You will be able to hear these outdoor concerts while sitting on your back porch—or perhaps even in your dining room. In this case, the sellers and buyers of concert tickets may both be quite satisfied with their voluntary exchange, but you have no voice in their market transaction.
The effect of a market exchange on a third party who is outside, or external, to the exchange is called an externality. Because externalities that occur in market transactions affect other parties beyond those involved, they are sometimes called spillovers.
Externalities can be negative or positive. If you hate country music, then having it waft into your house every night would be a negative externality. If you love country music, then what amounts to a series of free concerts would be a positive externality.
Pollution as a negative externality
Pollution is a negative externality. Economists illustrate the social costs of production with a demand and supply diagram. The social costs include the private costs of production incurred by the company and the external costs of pollution that are passed on to society.
The diagram below shows the demand and supply for manufacturing refrigerators. The demand curve,
| Price | Quantity demanded | Quantity supplied before considering pollution cost | Quantity supplied after considering pollution cost |
|---|---|---|---|
| $600 | 50,000 | 40,000 | 30,000 |
| $650 | 45,000 | 45,000 | 35,000 |
| $700 | 40,000 | 50,000 | 40,000 |
| $750 | 35,000 | 55,000 | 45,000 |
| $800 | 30,000 | 60,000 | 50,000 |
| $850 | 25,000 | 65,000 | 55,000 |
| $900 | 20,000 | 70,000 | 60,000 |
The situation is not actually that simple, however. Pollution is created as a byproduct of the metals, plastics, chemicals, and energy that are used in manufacturing refrigerators. Let’s say that, if these pollutants were emitted into the air and water, they would create costs of $100 per refrigerator produced. These costs might occur because of injuries to human health, impact on property values, destruction of wildlife habitat, reduction of recreation possibilities, or because of other negative impacts.
In a market with no anti-pollution restrictions, firms can dispose of certain wastes at no cost. Now imagine that firms that produce refrigerators must factor in these external costs of pollution—that is, the firms have to consider not only the costs of labor and materials needed to make a refrigerator but also the broader costs to society from pollution. If the firm is required to pay $100 for the additional external costs of pollution each time it produces a refrigerator, production becomes more costly and the entire supply curve shifts up by $100.
Notice the fourth column of the table above. Taking external costs of pollution into account, the firm will need to receive a price of $700 per refrigerator and produce a quantity of 40,000. You can also see this shift on the graph by looking at supply curve
Remember that supply curves are based on choices about production that firms make while looking at their marginal costs; demand curves are based on the benefits that individuals perceive while maximizing utility. If no externalities existed, private costs would be the same as the costs to society as a whole, and private benefits would be the same as the benefits to society as a whole. Thus, if no externalities existed, the interaction of demand and supply would coordinate social costs and benefits.
But the reality is that externalities do exist. Because of this, a supply curve showing private costs doesn't actually represent all social costs.
Because externalities represent a case where markets no longer consider all social costs but only some of them, economists commonly refer to externalities as an example of market failure. When there is market failure, the private market fails to achieve efficient output because either firms do not account for all costs incurred in the production of output and/or consumers do not account for all benefits obtained, in the case of a positive externality. In the case of pollution, at the market output, social costs of production exceed social benefits to consumers, and the market produces too much of the product.
There's a general concept here. If firms are required to pay the social costs of pollution, they create less pollution but produce less of the product and charge a higher price.
Summary
- Economic production can cause environmental damage. This tradeoff arises for all countries, whether high-income or low-income, and whether their economies are market-oriented or command-oriented.
- An externality, sometimes called a spillover, occurs when an exchange between a buyer and seller has an impact on a third party who is not part of the exchange. Externalities can be positive or negative.
- Market failure is when the market does not allocate resources on its own efficiently in a way that balances social costs and benefits; externalities are one example of a market failure.
- Social costs are costs that include both the private costs incurred by firms and also additional external costs incurred by third parties outside the production process.
Self-check questions
Identify whether each of the following situations is an example of a negative or a positive externality:
- You are a bird watcher and your neighbor has put up several birdhouses in the yard as well as planting trees and flowers that attract birds.
- Your neighbor paints his house a hideous color.
- Investments in private education raise your country’s standard of living.
- Trash dumped upstream flows downstream right past your home.
- Your roommate is a smoker, but you are a nonsmoker.
Identify whether the market supply curve will shift right or left or stay the same in the following situations:
- Firms in an industry are required to pay a fine for their emissions of carbon dioxide.
- Companies are sued for polluting the water in a river.
- Power plants in a specific city are not required to address the impact of their emissions on the quality of air.
- Companies that use fracking to remove oil and gas from rock are required to clean up the damage.
For each of your answers to the question above determine if equilibrium price will rise, fall, or stay the same.
The supply and demand conditions for a manufacturing firm are given in the table below. The third column represents a supply curve without taking the additional external cost of pollution into account. The fourth column represents the supply curve when the firm is required to take the additional external cost of pollution into account. Identify the equilibrium before the additional external cost of production is included and after the additional external cost of production is included.
| Price | Quantity demanded | Quantity supplied without paying the cost of the pollution | Quantity supplied after paying the cost of the pollution |
|---|---|---|---|
| $10 | 450 | 400 | 250 |
| $15 | 440 | 440 | 290 |
| $20 | 430 | 480 | 330 |
| $25 | 420 | 520 | 370 |
| $30 | 410 | 560 | 410 |
Review questions
- What is an externality?
- Give an example of a positive externality and an example of a negative externality.
- What is the difference between private costs and social costs?
- In a market without environmental regulations, will the supply curve for a firm take into account private costs, external costs, both, or neither? Explain.
Critical-thinking question
Suppose you want to put a dollar value on the external costs of carbon emissions from a power plant. What information or data would you obtain to measure the external—not social—cost?
Problems
- Show the market for cigarettes in equilibrium, assuming that there are no laws banning smoking in public. Label the equilibrium private market price and quantity as
- Refer to the first table in this article. The externality created by the production of refrigerators was $100. However, once both the private and additional external costs were taken into consideration, the market price increased by only $50. If the external costs were $100 why did the price only increase by $50 when all costs were taken into account?
- The table below shows the supply and demand conditions for a firm that will play trumpets on the streets when requested.
| P | Qd | Qs1 | Qs2 |
|---|---|---|---|
| $20 | 0 | 10 | 8 |
| $18 | 1 | 9 | 7 |
| $15 | 2.5 | 7.5 | 5.5 |
| $12 | 4 | 6 | 4 |
| $10 | 5 | 5 | 3 |
| $5 | 7.5 | 2.5 | 0.5 |
Want to join the conversation?
Can any one explain second problem ( If the external costs were $100 why did the price only increase by $50 when all costs were taken into account?) to me? I cannot understand the question.(7 votes)
The $50 price increase was the extra costs that the consumers had to pay. Producers paid the other $50.(9 votes)
The critical thinking question is confusing. It asks one to to measure the 'external--not social--costs'. However the article states above that social costs include both private costs and external costs. Is there a category of external costs that isn't considered part of social cost? Or did the question mean 'external costs, not private costs'?(6 votes)
"Social costs are costs that include both the private costs incurred by firms and also additional external costs incurred by third parties outside the production process."
So, "social costs" = all producer costs + external costs. It's the total cost to the economy/world for that production/service/whatever. External costs are a subset of that - they're the costs to the system that aren't paid by the producer/manufacturer/service supplier/whatever.
So, to answer your specific questions: yes, all external costs are part of the social cost, by definition and yes, that is what they're asking. Your posing the same question but wording it differently. I suspect they've worded it in that way to drive home the idea that social cost = all costs and is distinct from the concept of external costs.
Also, because economics.(6 votes)
- In the cigarette problem: since the negative externality is created by the consumers would that mean there's a shift in the demand curve instead of the supply curve?(5 votes)
what is the solution to the smoking problem?(5 votes)- When you sketch your demand and supply equilibrium, increase the price from P(M) to P(E). The price increase accounts for the increased cost to consumers from the secondhand smoke. Then, trace the line from P(E) to find the new point on the demand curve and new point on the supply curve. The result will be a triangle of deadweight loss between the old equilibrium point E(M), P(E) and the demand curve, and Q(E) and the supply curve. Hope this helps - not easy without the ability to draw.(1 vote)
Please, can someone help me with the second part question about problems? Thanks(1 vote)
Why does it shift up to a hundred each time?(1 vote)
Why does it shift up to a hundred each time?Can any one explain second problem ( If the external costs were $100 why did the price only increase by $50 when all costs were taken into account?) to me? I cannot understand the question.The critical thinking question is confusing. It asks one to to measure the 'external--not social--costs'. However the article states above
that social costs include both private costs and external costs. Is there a category of external costs that isn't considered part of social cost? Or did the question mean 'external costs, not private costs'?(1 vote)
Can pollution/oil be removed by hand? How is it removed? How is pollution created(1 vote)- The last problem:
The quantity of supply decreased after counting the external cost. We can definitely see that it is a negative external cost. In this case, the possible negative externality should be that people living alongside the street feel noisy about the trumpet.
Only when the private cost is considered, the equilibrium price is $10 and the equilibrium quantity should be 5. This is because the quantity of demand is the same as the quantity of supply(Qs1) at the price of $10(quantity is both 5).
When externality is considered, the equilibrium price is $12 and the quantity is 4. This is because the quantity of demand is the same as the quantity of supply(Qs2) at the price of $12(quantity is both 4).
Compare the price and quantity before and after the externality is considered, we can conclude that the equilibrium price increases and the quantity decreases after the externality.(1 vote) - Regarding "If the external costs were $100 why did the price only increase by $50 when all costs were taken into account?", "Tejas" commented that the supplier paid half and consumer paid the other half.
Is it always half-half? I didn't know this. Is it because I am missing training in fundamentals which I need to get? Thanks(1 vote)