环境经济学3ppt课件

1、Fundamentals of Environmental EconomicsWeiqi CHEN 陈伟琪Environmental Science Research Center Xiamen UniversityChapter 3 Benefits and Costs, Supply and DemandChapter 4 Economic Efficiency and MarketsChapter 5 The Economics of Environmental QualitySECTION 2: ANALYTICAL TOOLSThis section covers some of t

2、he basic ideas of economics and of their application to environmental matters. the purpose : to develop a set of analytical tools - use to focus on issues of environmental qualityChapter 3 Benefits and Costs, Supply and Demand In this chapter we cover certain basic tools of microeconomics - use in a

3、nalyzing environmental impacts and policiesA key aspect of an economic approach to decision making is the evaluation of the benefits and costs of any action. economic actions, including environmental actions - have two sides: create value encounter costs evaluate / trade-offsWILLINGNESS TO PAYDemand

4、AGGREGATE DEMAND/WILLINGNESS TO PAYBENEFITSCOSTOpportunity CostCost CurvesThe Shapes of Cost CurvesTECHNOLOGYTHE EQUIMARGINAL PRINCIPLE MARGINAL COST AND SUPPLYWILLINGNESS TO PAY The value side of our analysis is based on the fundamental notion: - individuals have preferences for goods and services;

5、 given a choice they can express preferences for one good over another, or one bundle of goods over another bundle The value of a good to somebody is what he is willing to pay for it. how much a person is willing to pay to obtain some good or service, or some environmental asset - its partly a quest

6、ion of individual valuesexamplesthe Canadian Rockiessacrifice a lota quiet living environment the habitat of unique animal speciesthe habitat of unique plant speciesGolden gate bridge a persons wealth affects their willingness to sacrifice; the more wealthy a person is, the better they can afford to

7、 pay for various goods and services. Willingness to pay, in other words, also reflects ability to pay. Lets consider the willingness to pay of a person for a particular good. Assume that the person has none of the good to begin with. ask or perhaps deduce from watching her spend her money - how much

8、 she would be willing to pay for a single unit of a good rather than go withoutFig.1 The Concept of Willingness to PayWILLINGNESS TO PAY 38261712$Units of the Good people can consume fractions of items in addition to integer values -a smoothly shaped willingness-to-pay curve These numbers depict a f

9、undamental relationship of economics: the notion of diminishing willingness to pay. As the number of units consumed increases, the willingness to pay for additional units of that good normally goes down. Exceptional circumstancesstampsubmachine gundrug addictreputed commodityMarginal边沿is thus a word

10、 that describes the additional willingness to pay of a person for one more unit. we need to make a distinction between total and marginalIf the person has two units of the good, he want to pay $17 for a third unit - the marginal willingness to pay for the third unit the total willingness to pay for

11、a given consumption levelat a level of three units- the total willingness to pay is $8l ( $38 for the first + $26 for the second + $l7 for the third ) a+b Demand There is another way of looking at these marginal willingness-to-pay relationships. - demand curves An individual demand curve shows the q

12、uantity of a good or service that the individual in question would demand at any particular price. 需求即有支付才干的需求marginal willingness to pay / demand curve For example, suppose a person whose marginal willingness to pay / demand curve is shown in bottom part of Figure l is able to purchase this item at

13、 a unit price of $l7. The quantity he would demand at this price is three units. An individuals demand / marginal willingness-to-pay curve for a good or service is a way of summarizing their personal consumption attitudes and capabilities for that good. tastes preferencesIncomesFig.2 Typical Demand

14、/ Marginal Willingness-to-Pay Curves tastes / preferences depend on a lot of factors :psychological and historical factorsexperiences informationFig.2 (b)-the same consumers demand curve for a good before / after outdoor wilderness experiencesa food item after / before an announcement of the presenc

15、e in it of pesticide residuesFig. 2 (b): - The different consumers demand curve for a good - the same consumers demand curve for two different goods demand curves - curvilinear lines rather than straight lines A straight-line demand relationship would imply a uniform change in the quantity demanded

16、as its price changes. For most goods, however, this is unlikely to be true. waterat low prices and high rates of consumption; at high prices and low quantity demandeda demand relationship - convex to the origin- relatively flat at low prices and steep at higher prices Individual demand curves indeed

17、 summarize the attitudes of single individualsindividuals make decisions with only themselves in mind ? Some people may indeed act this way. But for most there are many other powerful motives that affect their demands for different goods, including altruism toward friends and relatives, feelings of

18、civic virtue toward their communities, a sense of social responsibility toward fellow citizens, and so on. Individual tastes and preferences spring from these factors as well as from more narrow considerations of personal likes and dislikes. AGGREGATE DEMAND/WILLINGNESS TO PAY When we examine real-w

19、orld issues of environmental quality and pollution-control policy, we normally focus our attention on the behaviour of groups of people rather than single individuals. Our interest is in the total, or aggregate, demand / marginal willingness to pay of defined groups of people. An aggregate demand cu

20、rve is the summation of a number of individual demand curves. What individuals are involved depends on which particular aggregation we want to look at. the demand of people living in Xiamen for clean water from Jiulong river the demand by people living in the county for public parkThe way in which t

21、hese individual demand curves are summed up depends upon whether the good in question is a private or a public good. Fig. 3 Aggregate Demand / Marginal Willingness-to-Pay Curve - a very simple curve for a private good- the group consists of only three people (A, B, C)summing these individual demand

22、curves horizontally Person A: at l0 units -MWTP $8Person B: at 6 units -MWTP $8Person C: at 8 units -MWTP $8 On the aggregate level (24 units), the marginal willingness to pay is also $8. BENEFITS The word benefits clearly implies being made better off; if someone is benefited by something, their po

23、sition is improved, they are made better off. Conversely, if they are made worse off, it must be because benefits were somehow taken away from them.The benefits that people get from something are equal to the amount they are willing to pay for that thing. It means we can use ordinary demand curves t

24、o determine the benefits of making various things available to people. two aggregate demand curves - the two groups of peopleto estimate the total benefits from quantity ql to quantity q2 areas under the demand curves between quantity ql and quantity q2 area b / total area a + b The people with the

25、higher demand curve must place a greater value on this item - they are willing to pay more than the people whose demand curve is the lower function degradation of the natural environmentthe impacts of environmental programs and policies a clear notion of the value that people place on different thin

26、gs recognize shortcomingsFor one thing demand, and therefore benefits are often very hard to measure when it concerns environmental questions.Demand curves are critically affected by the ability to pay for something as well as preferences. The lower demand curve could represent a group of people wit

27、h lower incomes than those with the higher demand curve. lead us to conclude that the increase in quantity of q2 ql would produce benefits that the lower income people value less than the higher income people. While the logic of the concept is clear, we have to be careful in using it, especially whe

28、n we are dealing with groups of people with diverse income levels. An individuals demand for something is clearly affected by how much he knows about it. A person would not be willing to pay for a good if he was ignorant of its very existence. We dont fully understand many of the impacts that enviro

29、nmental degradation is having; furthermore, peoples views about the importance of many of these impacts vary due to influences by the media, the scientific press, and so on. in some of these cases: people are influenced by all kinds of real and imagined factors be cautious about taking peoples deman

30、d curves of the moment, as true expressions of the benefits of environmental actions COST - the other sideAny production process requires a variety of productive inputs labour, machinery of various descriptions, energy, raw materials, waste handling equipment, and so on. Valuation of these inputs is

31、 straight forward for a private firm operating in a market economy: they are valued according to what they cost to procure in the markets for these items.a broader concept - opportunity cost Productive inputs used to produce a particular good could have been used to produce a variety of other goods

32、and services.The opportunity cost of producing something consists of the maximum value of other outputs we could and would have produced had we not used the resources to produce the item in question. People who volunteer their time to clean up trash in parks or on roadsides production residuals are

33、pumped into water environment - affect environmental qualityOpportunity costs are relevant in any situation where a decision must be made about using productive resources for one purpose rather than another. For a public agency with a given budget, the opportunity costs of a particular policy are th

34、e value of alternative policies they may have pursued. For a consumer, the opportunity cost of spending time searching for a particular item is the value of the next most valuable thing to which they may have devoted their time. Cost Curves Cost information can be summarized with cost curves, which

35、are geometric representations of production costs. differentiate between marginal costs and total costs Fig. 5 The Concept of Marginal Costwith quantity on the horizontal axis and a monetary index on the vertical axisThe cost curves are meant to apply to a single producing organization, a firm, or perhaps a public agency, that is producing some good or service.SUMMARY