农丁专业资源与环境经济学全册配套完整课件5.pptx

1、农丁专业资源与环境经济学农丁专业资源与环境经济学全册配套完整课件全册配套完整课件5Chapter 1 Visions of The FutureContents:1. Introduction2. The basic pessimist model3. The basic optimist model4. The road ahead5. Issues1. Introduction1.1The Self-extinction Premise1.2The Use of Models1.3Thinking About The Future1.1The Self-extinction Premise

2、Thomas Malthus foresaw that population growth would outstrip the growth of food supply, resulting in starvation and death, if reproduction was encouraged.1.1The Self-extinction PremiseModern ecologists have suggested that ecological disruption would occur with disastrous consequences for humanity if

3、 the “carrying capacity”（承载能力）（承载能力） of environment is exceeded widespread.1.1The Self-extinction PremiseEconomists have been concerned with topics such as exhaustible resources（可（可耗竭资源）耗竭资源） and pollution. Now, weve come to better understand the relationship between humanity and the environment and

4、 how that relationship affects, and is affected by, economic and political institutions.1. 2 The Use of ModelsIn economics, as in most other disciplines, we use models to illustrate complex subjects, such as relationships between the economy and the environment. In using these models, we should also

5、 be sensitive to their limitations.Limitations of models:Models are simplified characterizations of reality.Models may yield conclusions that are dead wrong.Models are useful abstractions that should always be viewed with some skepticism.1. 3 Thinking About The FutureThe basic pessimist model(悲观模型悲观

6、模型)The basic optimist model(乐观模型乐观模型)2. The Basic Pessimist Model2.1 Conclusions of Pessimist Model2.2 The Nature of the Model2.1 Conclusions of Pessimist ModelThe first suggests that within a time span of less than 100 years with no major change in the physical, economic, or social relationships th

7、at have traditionally governed world development, society will run out of the nonrenewable resources on which the industrial base depends. When the resources have been depleted, a precipitous collapse of the economic system will result decreased food production, and a decline in population as the de

8、ath rate soars.The second conclusion is that piecemeal approaches to solving the individual problems will not be successful.The third suggests that overshoot and collapse can be avoided only by an immediate limit on population and pollution, as well as cessation of economic growth.2.2 The Nature of

9、the ModelThe dominant characteristic of the model is exponential growth（指数增长）（指数增长） coupled with fixed limits.Exponential growth in any variable implies that the absolute increases in that variable will be greater and greater each year.The higher the rate of growth in resource consumption, the faste

10、r a fixed stock of it will be exhausted.2.2 The Nature of the ModelSeveral resources are held in fixed supply by the model.This basic structure of the model is in some ways reinforced and in some ways tempered by the presence of numerous positive and negative feedback loops.Positive feedback loops (

11、正反馈回路)are those in which secondary effects tend to reinforce the basic trend.A negative feedback loop(负反馈回路负反馈回路) is self-limiting rather than self-reinforcing.3. The Basic Optimist Model3.1 Conclusions of the Optimist Model3.2 The Nature of the Model3.1 Conclusions of the Optimist ModelThe Simon vi

12、sion of the future concludes:The standard of living has arisen along with the size of the worlds population since the beginning of recorded time. And with increases in income and population have come less severe shortages, lower costs, and an increased availability of resources, including a clearer

13、environment and greater access to natural recreation areas. And there is no convincing reason why these trends toward a better life, and toward lower prices for raw materials, should not continue indefinitely.3.2 The Nature of the ModelFirst, historically human resourcefulness has always overcome bo

14、th scarcities of resources and environmental problems associated with economic activity.Second, no compelling reason why those trends cannot continue indefinitely into the future.3.2 The Nature of the ModelSeveral observations to bolster Simons argument.Food production is not likely to be a limit fo

15、r increased agrarian or agro-production.Natural resources have not become more scarce over time. Apparent shortages are due more to problems with human behavior than to any physical lack of availabilityPollution levels have declined as population and incomes increased.3.2 The Nature of the ModelWhat

16、 are the driving forces behind these outcomes?Simon suggests that our economic and political systems respond to scarcity in ways which eliminate or diminish its impact.4. The Road AheadThe differences between the pessimist and optimist model depend on how human behavior is perceived.If intensifying

17、pressure on the environment results in a behavioral response which intensifies the pressures, pessimism is justified.If the human responses either currently are reducing those pressures or could be reformed so as to reduce those pressures, then optimism may be justified.4. The Road AheadThe field of

18、 environmental and natural resource economics has become an important source of ideas for coping with environmental problems. Not only does the field provide a firm basis for understanding the human sources of environmental problems; this understanding provides a firm foundation for crafting specifi

19、c solutions to these problems.5. IssuesIs the problem correctly conceptualized as exponential growth with fixed, immutable resource limits? Does the earth have a finite carrying capacity?If these limits do exist, have they been measured correctly or, as Simon argues, has the Beyond the Limits team b

20、een rather myopic in the way they treat resources? How can the carrying-capacity concept be operationalized? Do current levels of economic activity exceed the carrying capacity?5. IssuesHow does the economic system respond to scarcities? Does the process involve mainly positive feedback loops? Would

21、 it intensify or ameliorate any initial scarcities? Is the overshoot-and collapse syndrome an accurate portrayal of the future?What is the role of the political system in controlling these problems? In what circumstances is government intervention necessary? Is this intervention uniformly benign, or

22、 can it make the situation worse? What is an appropriate role for the executive, legislative, and judicial branches?5. IssuesMany environmental problems involve a considerable degree of uncertainty about the severity of the problem and the effectiveness of possible solutions. Can our economic and po

23、litical institutions respond to this uncertainty in reasonable ways?5. IssuesCan the economic and political systems work together to eradicate poverty while respecting our obligations to future generations? Or does our obligation to future generations inevitably conflict with the desire to raise the

24、 living standards of those currently in absolute poverty? Can short-term and long-term goals be harmonized? How? What does the need to preserve the environment imply about the future of economic activity in the industrialized nations? In the less industrialized nations?Further reading:The Limits to

25、GrowthBeyond the LimitsOur Common FutureChapter 2 Valuing The Environment: Concepts1. IntroductionMain contents:Develop the general conceptual framework used in economics to approach environmental problems.Examining the relationship between human actions, as manifested through the economic system, a

26、nd the environmental consequences of those actions.Establish criteria for judging the desirability of the outcomes of this relationship.2. The Human Environmental Relationship2.1 The Environment as an Asset2.2 The Economic Approach2.1 The Environment as an AssetIn economics the environment is viewed

27、 as a composite asset （复合资产）（复合资产） that provides a variety of services.Provides the economy with raw materials and energyAlso provides services directly to consumers, such as air, water, amenities, etc.2.1 The Environment as an AssetIf the environment is defined broadly enough, the relationship betw

28、een the environment and the economic system can be considered a closed system.A closed system （封闭系统）（封闭系统） is one in which no inputs are received from outside the system and no outputs are transferred outside the system.An open system （开放系统）（开放系统）is one in which the system imports or exports matter

29、or energy.2.1 The Environment as an AssetThe first law of thermodynamics （热力学（热力学第一定律）第一定律）The law states that energy and matter cannot be created or destroyed in a closed system.The law implies that the mass of materials flowing into the economic system from the environment has to either accumulate

30、 in the economic system or return to the environment as waste.2.1 The Environment as an AssetThe second law of thermodynamics （热力（热力学第二定律）学第二定律）The law states that entropy （熵） increases.Applied to energy processes, this law implies that no conversion from one form of energy to another is completely

31、efficient and that the consumption of energy is an irreversible process.Also implies that in the absence of new energy input, any closed system must eventually use up its energy.2.2 The Economic ApproachTwo different types of economic analysis can be applied to increase our understanding of the rela

32、tionship between the economic system and the environment.Positive economics （实证经济学）（实证经济学）attempts to describe what is, what was, or what will beNormative economics （规范经济学）（规范经济学）deals with what ought to be.3. Normative Criteria for Decision-MakingEconomists suggest that actions have both benefits （

33、收益）and costs （成本）. If the benefits exceed the costs, then the action is desirable. If the costs exceed the benefits, then the action is not desirable.If BC, then support the action, otherwise oppose the actionIf B/C1, support the action otherwise, oppose the action3. Normative Criteria for Decision-

34、MakingHow to measure benefits and costs?3. Normative Criteria for Decision-MakingBenefits （收益）can be derived from the demand curve for the good or service provided by the action. Demand curves （需求曲线）（需求曲线）measures the amount of a particular good people would be willing to purchase at various prices.

35、Figure 2.2Figure 2.33. Normative Criteria for Decision-MakingMeasuring total costs （总成本）（总成本）on the same set of axes involves logic similar to measuring total benefits.All costs should be measured as opportunity costs （机会成本）（机会成本）.It is important to stress that environmental services have costs even

36、 though they are produced without any human input.Total cost is simply the sum of the marginal costs （边际成本）（边际成本）.Figure 2.43. Normative Criteria for Decision-MakingSince net benefit （净收益）（净收益）is defined as the excess of benefits over costs, it follows that net benefit is equal to that portion of th

37、e area under the demand curve which lies above the supply curve.Figure 2.53. Normative Criteria for Decision-MakingThe analysis we have covered so far is very useful for thinking about actions where time is not an important factor.How can we make choices when the benefits and costs may occur at diff

38、erent points in time?In order to incorporate timing, the decision rule must provide a way to compare the net benefit received in one period with the net benefit received in another. The concept that allows this comparison is called present value （现值）（现值）.3. Normative Criteria for Decision-MakingThe

39、present value of a one-time net benefits received n years from now is The present value of a stream of net benefits B0,Bn received over a period of n years is computed as 3. Normative Criteria for Decision-MakingIt is now possible to show how this analysis can be used to evaluate actions.First calcu

40、late the present value （现值） of net benefits （净收益） from the actionIf the present value is greater than zero, the action should be supported. Otherwise it should not.4. Finding the Optimal OutcomeThree steps proceeded by normative analysis:First we will identify an optimal （最优的） outcome.Second we will

41、 attempt to discern the extent to which our institutions produce optimal outcomes and, where divergences occur between actual and optimal outcomes, to attempt to uncover the behavioral sources of the problems.Finally designing appropriate policy solutions. Examples:Consider the rising number of depl

42、eted ocean fisheries. Depleted fisheries not only jeopardize oceanic biodiversity, but also pose a threat to both the individuals who make their living from the sea and the communities that have depended on fishing to support their local economies. How would an economist attempt to understand and to

43、 resolve this problem?Example:The first step would involve defining the optimal stock （最优存量）or the optimal rate of harvest （最优捕捞率）of the fishery.The second step would compare this level with the actual stock and harvest levels.The third step would reach the solutions.4.1 Static EfficiencyThe chief n

44、ormative economic criterion for choosing among various allocations occurring at the same point in time is called static efficiency （静态效率）（静态效率）.An allocation of resources is said to satisfy the static efficiency criterion if the net benefit from the use of those resources is maximized （最大化）by that a

45、llocation.4.1 Static EfficiencyFirst Equimarginal Principle (the “Efficiency Equimarginal Principle”)（第一等边际原理）: Net benefits are maximized when the marginal benefits from an allocation equal the marginal costs.Pareto Optimality （帕累托最优）（帕累托最优）: Allocations are said to be Pareto optimal if no other fe

46、asible allocation could benefit some people without any deleterious effects on at least one other person.4.2 Dynamic EfficiencyThe traditional criterion used to find an optimal allocation when time is involved is called dynamic efficiency （动态效率）（动态效率）.An allocation of resources across n time periods

47、 satisfies the dynamic efficiency criterion if it maximizes the present value of net benefits that could be received from all the possible ways of allocation those resources over the n periods.5. Applying the conceptsPollution controlPreservation versus development二氧化碳减排的效益评估 二氧化碳减排的收益？ 碳社会成本：指二氧化碳排

48、放的少量增长导致的经济损失现值（如，海平面的上升、洪水、农业产量的变化、及变化了的生态服务）的边际增长。Further reading:A 迈克里 弗里曼，环境与资源价值评估理论与方法，中国人民大学出版社，2002Objectives & Requirements:Understand the human environmental relationshipGrasp the normative criteria for decision-making and optimal outcomeUnderstand the meaning of “static efficiency” and “d

49、ynamic efficiency”Problems:One convenient way to express the willingness-to-pay relationship between price and quantity is to use the inverse demand function. In an inverse demand function, the price consumers are willing to pay is expressed as a function of the quantity available for sale. Suppose

50、the inverse demand function or a product is P=80-q, and the marginal cost of producing it is MC=1q, where P is the price of the product and q is the quantity demanded and/or supplied. How much would be supplied in a static efficient allocation?What would be the magnitude of the net benefits?Chapter