农丁专业资源与环境经济学全册完整教学课件3.ppt

1、Chapter 1 Visions of The Future Contents: 1. Introduction 2. The basic pessimist model 3. The basic optimist model 4. The road ahead 5. Issues 1. Introduction 1.1The Self-extinction Premise 1.2The Use of Models 1.3Thinking About The Future 1.1The Self-extinction Premise Thomas Malthus foresaw that p

2、opulation growth would outstrip the growth of food supply, resulting in starvation and death, if reproduction was encouraged. 1.1The Self-extinction Premise Modern ecologists have suggested that ecological disruption would occur with disastrous consequences for humanity if the “carrying capacity” （承

3、载能力）（承载能力） of environment is exceeded widespread. 1.1The Self-extinction Premise Economists 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 how that relationship

4、affects, and is affected by, economic and political institutions. 1. 2 The Use of Models In 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 be sensitive to thei

5、r 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 Future The basic pessimist model(悲观模型悲观模型) The basic o

6、ptimist model(乐观模型乐观模型) 2. The Basic Pessimist Model 2.1 Conclusions of Pessimist Model 2.2 The Nature of the Model 2.1 Conclusions of Pessimist Model The first suggests that within a time span of less than 100 years with no major change in the physical, economic, or social relationships that have t

7、raditionally 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 death rate

8、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 the Mo

9、del The 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 faster a

10、 fixed stock of it will be exhausted. 2.2 The Nature of the Model Several 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 Model 3.1 Conclusions of the Optimist Model 3.2 The Nature of the Model 3.1 Conclusions of the Optimist Model The

12、Simon vision 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

13、 clearer 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 Model First, historically human resourcefulness has always

14、overcome both 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 Model Several observations to bolster Simons argument. Food production is not likely t

15、o be a limit for 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 availability Pollution levels have declined as population and incomes increased. 3.2 The Natur

16、e of the Model What 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 Ahead The differences between the pessimist and optimist model depend on how human behavior is perc

17、eived. If intensifying 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. T

18、he Road Ahead The field of 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 found

19、ation for crafting specific solutions to these problems. 5. Issues Is 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

20、 the Beyond the Limits team been 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. Issues How does the economic system respond to scarcities? Does the process involve mainly

21、 positive feedback loops? Would 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 i

22、ntervention uniformly benign, or can it make the situation worse? What is an appropriate role for the executive, legislative, and judicial branches? 5. Issues Many environmental problems involve a considerable degree of uncertainty about the severity of the problem and the effectiveness of possible

23、solutions. Can our economic and political institutions respond to this uncertainty in reasonable ways? 5. Issues Can 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 c

24、onflict with the desire to raise the 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 n

25、ations? Further reading: The Limits to Growth Beyond the Limits Our Common Future Chapter 2 Valuing The Environment: Concepts 1. Introduction Main contents: Develop the general conceptual framework used in economics to approach environmental problems. Examining the relationship between human actions

26、, as manifested through the economic system, and the environmental consequences of those actions. Establish criteria for judging the desirability of the outcomes of this relationship. 2. The Human Environmental Relationship 2.1 The Environment as an Asset 2.2 The Economic Approach 2.1 The Environmen

27、t as an Asset In economics the environment is viewed 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 energy Also provides services directly to consumers, such as air, water, amenities, etc. 2.1 The Environment as an Asset If the envi

28、ronment is defined broadly enough, the relationship between 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）（

29、开放系统）is one in which the system imports or exports matter or energy. 2.1 The Environment as an Asset The 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 th

30、e economic system from the environment has to either accumulate in the economic system or return to the environment as waste. 2.1 The Environment as an Asset The 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

31、that no conversion from one form of energy to another is completely 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 Approach Two different types of eco

32、nomic analysis can be applied to increase our understanding of the relationship 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 be Normative economics （规范经济学）（规范经济学）deals with what ought to be. 3. Normative Criter

33、ia for Decision-Making Economists suggest that actions have both benefits （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 action If B/C1, suppo

34、rt the action otherwise, oppose the action 3. Normative Criteria for Decision-Making How to measure benefits and costs? 3. Normative Criteria for Decision-Making Benefits （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 a

35、mount of a particular good people would be willing to purchase at various prices. Figure 2.2 Figure 2.3 3. Normative Criteria for Decision-Making Measuring 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 co

36、sts （机会成本）（机会成本）. It is important to stress that environmental services have costs even 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 2.4 3. Normative Criteria for Decision-Making Since net benefit （净收益）（净收益）is defined as th

37、e excess of benefits over costs, it follows that net benefit is equal to that portion of the area under the demand curve which lies above the supply curve. Figure 2.5 3. Normative Criteria for Decision-Making The analysis we have covered so far is very useful for thinking about actions where time is

38、 not an important factor. How can we make choices when the benefits and costs may occur at different 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 allow

39、s this comparison is called present value （现值）（现值）. 3. Normative Criteria for Decision-Making The 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 Decis

40、ion-Making It is now possible to show how this analysis can be used to evaluate actions. First calculate the present value （现值） of net benefits （净收益） from the action If the present value is greater than zero, the action should be supported. Otherwise it should not. 4. Finding the Optimal Outcome Thr

41、ee steps proceeded by normative analysis: First we will identify an optimal （最优的） outcome. Second we will 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

42、 the problems. Finally designing appropriate policy solutions. Examples: Consider the rising number of depleted 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 hav

43、e depended on fishing to support their local economies. How would an economist attempt to understand and to 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

44、 the actual stock and harvest levels. The third step would reach the solutions. 4.1 Static Efficiency The chief normative 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 sati

45、sfy the static efficiency criterion if the net benefit from the use of those resources is maximized （最大化）by that allocation. 4.1 Static Efficiency First Equimarginal Principle (the “Efficiency Equimarginal Principle”)（第一等边际原理）: Net benefits are maximized when the marginal benefits from an allocation

46、 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 feasible allocation could benefit some people without any deleterious effects on at least one other person. 4.2 Dynamic Efficiency The traditional criterion used to find an optimal allo

47、cation when time is involved is called dynamic efficiency （动态效率）（动态效率）. An allocation of resources across n time periods 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 t

48、he n periods. 5. Applying the concepts Pollution control Preservation 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， 2002 Objectives hence the maximum sustainable yield is equa

49、l to this maximum growth and it represents the largest catch that can be perpetually sustained. 13.2.2 Static Efficient Sustainable Yield Is the maximum sustainable yield synonymous with efficiency? The answer is no. Efficiency is associated with maximizing the net benefit from the use of resource.

50、If we are to define the efficient allocation, we must include the costs of harvesting as well as the benefits. Figure 13.2 13.2.3 Dynamic Efficient Sustainable Yield When positive discount rates are introduced, the efficient level of effort would be increased beyond that suggested by the static effi