policy adoption rules and global warming although there is widespread agreement about the dangers of global warming and the resulting need to cut down emissions there does not seem to be general agreement about the exact form the policy should take or the timing of its adoption failure to adopt and implement policies against global warming reflects the complexity of the problem the uncertainties of climate change and the cost of policy adoption issues associated with the interactions between uncertainties and irreversibilities in determining the timing of policy adoption are analyzed by using the methodology of optimal stopping rules optimal policy functions are derived for cooperative and noncooperative solutions with differential game representation issues associated with the empirical application of the optimal policy rules are also considered

uncertainty and endogenous technical change in climate policy models until recently endogenous technical change and uncertainty have been modeled separately in climate policy models in this paper we review the emerging literature that considers both these elements together taken as a whole the literature indicates that explicitly including uncertainty has important quantitative and qualitative impacts on optimal climate change technology policy

mixing and matching prospective financial sector mergers and market valuation abstract which types of mergers are likely to be most productive for banks and other financial firms in the us from a management perspective mixing disparate firms may be difficult but may offer significant gains from diversification the opposite applies to matching similar firms this paper considers life insurance property and casualty insurance securities and commercial firms as potential matches for banks it examines a measure of diversification gains from potential consolidation based on option pricing and a model of the building blocks of the industries based on arbitrage pricing theory the results identify potential diversification gains from virtually all combinations involving banking and insurance which arise because common factors are combined in different ways and because insurance is already well diversified

flexibility and uncertainty the preserving of flexibility when faced with uncertainty is a neglected aspect of behaviour under risk yet it is an important factor in decisions to hold liquid assets or delay irreversible investment this paper formalizes the notion of flexibility in a sequential decision context and relates its value to the amount of information an agent expects to receive a rudimentary money demand model is developed embodying these ideas and the history of flexibility as an economic concept is traced choices are frequently made between alternatives that imply different degrees of future commitment between a short term investment that leaves future options open for example and a long term one that by its very nature forecloses those options the relative attractiveness of the two depends on their probability distributions of payoffs over time a basic consideration in this choice is the recognition that beliefs about the risks governing these payoffs may change current doubts may be partially resolved in the near future this prospect decreases the attractiveness of the longer term commitment in that one is able to respond less fully to new information and even if it does not directly affect the risks associated with shorter term choices enhances their appeal this paper formalizes the above remarks by establishing connections between the following two partial orderings the first is an ordering based on variability of beliefs one set of beliefs is more variable than another if more final risk is resolved at an intermediate stage the more one expects to learn by an intermediate period relative to what one knows today the more variation one is anticipating in beliefs about the final outcome the second is an ordering of current actions or positions based on flexibility one position is more flexible than another if it leaves available a larger set of future positions at any given level of cost these two orderings are incorporated in a simple sequential decision model to suggest the following behavioural principle the more variable are a decision maker s beliefs the more flexible is the position he will choose this principle potentially applies whenever i there will be opportunities to act after further information is received and ii current actions influence either the attractiveness or availability of different future actions

on the frequency of large stock returns putting booms and busts into perspective textabstractnumerous articles have investigated the distribution of share prices and find that the returns are fat tailed nevertheless there is still controversy about the amount of probability mass in the tails and hence about the most appropriate distribution to use in modeling returns this controversy has proven hard to resolve as the alternatives are non nested we employ extreme value theory focusing exclusively on the larger observations in order to assess the tail shape within a unified framework we find that at least the first two moments exist this enables one to generate robust probabilities on large returns which put the recent stock market swings into historical perspective

regulating stock externalities under uncertainty abstract using a simple analytical model incorporating benefits of a stock costs of adjusting the stock and uncertainty in costs we uncover several important principles governing the choice of price based policies e g taxes relative to quantity based policies e g tradable permits for controlling stock externalities as in weitzman rev econom stud 41 4 1974 477 the relative slopes of the marginal benefits and costs of controlling the externality continue to be critical determinants of the efficiency of prices relative to quantities with flatter marginal benefits and steeper marginal costs favoring prices but some important adjustments for dynamic effects are necessary including correlation of cost shocks across time discounting stock decay and the rate of benefits growth applied to the problem of greenhouse gases and climate change we find that a price based instrument generates several times the expected net benefits of a quantity instrument

joint management of emission abatement and technological innovation for stock externalities we investigate how emission abatement and technological innovation provide different solutions to reduce pollutant emissions in the case of a stock externality emission abatement leads to a smooth and continuous adjustment of emissions conversely technological innovation has to be interpreted as an option on a less polluted environment and can justify the use of a pollution threshold above which it is optimal to start a research and development programme for a less polluting technology it is shown that technological innovation interferes with the traditional emission abatement approach the optimal abatement level is logically lowered once the less polluting technology is available nevertheless a temporary increase in emissions is optimal during the research and development period the usual pigouvian tax system proves to remain an efficient corrective instrument a numerical application to the greenhouse effect is provided

institutions and equilibrium in the united states supreme court over the last decade the scholarship on judicial politics has increasingly emphasized the strategic aspects of decision making in the united states supreme court this scholarship however has struggled with two significant limitations the restriction to unidimensional policy spaces and the assumption of binary comparisons of alternatives these two assumptions have the advantage of implying stable predictable outcomes but lack a sound theoretical foundation and assume away potentially important aspects of strategic behavior on the court in this article we identify institutional features of the court that under certain conditions allow us to relax these two assumptions without sacrificing stable predictable policy outcomes in particular we formalize the part by part opinion voting used by the justices a feature that together with separable preferences over policy issues implies stable policy outcomes around the issue by issue median of the justices

collusion under asymmetric information when applied to groups the revelation principle postulates a bayesian nash behavior between agents their binding agreements are unenforceable or the principal can prevent them at no cost we analyze instead a mechanism design problem in which the agents can communicate between themselves and collude under asymmetric information we characterize the set of implementable collusion proof contracts both when the principal offers anonymous and nonanonymous contracts after having isolated the nexi and the stakes of collusion we proceed to a normative analysis perform some comparative statics discuss our concept of collusion proofness and provide some insights about transaction costs in side contracting

the role of uncertainty and learning for the success of international climate agreements abstract transnational externalities e g transboundary pollution trade contagious diseases and terrorism warrant coordination and cooperation between governments but this proves often difficult one reason for the meager success is the public good character of many of these economic problems encouraging free riding another reason one might suspect is uncertainty surrounding most environmental problems and in particular climate change this provides often an excuse for remaining inactive paradoxically some recent papers have concluded just the opposite the veil of uncertainty can be conducive to the success of international environmental cooperation in this paper we explain why and under which conditions this can be true however we argue that those conditions are the exception rather than the rule most important we suggest a mechanism for those conditions where learning has a negative effect on the success of cooperation which removes this effect or even turns it into a positive effect our results apply beyond the specifics of climate change to similar problems where cooperation generates positive externalities

quasi option value some misconceptions dispelled abstract we discuss a couple of important issues in the recent literature on quasi option value we show that the assertion that quasi option value can be negative in a model with independent learning is based on confusion between quasi option value which is always positive and the net benefit of preservation of a natural environment subject to development which is not we also explore the significance of different assumptions about the nature of learning and show that the result that quasi option value is positive is surprisingly robust

optimal learning on climate change why climate skeptics should reduce emissions climate skeptics typically argue that the possibility that global warming is exogenous implies that we should not take additional action towards reducing emissions until we know what drives warming this paper however shows that even climate skeptics have an incentive to reduce emissions such a directional change generates information on the causes of global warming since the optimal policy depends upon these causes they are valuable to know although increasing emissions would also generate information that option is inferior due its irreversibility we show that optimality can even imply that climate skeptics should actually argue for lower emissions than believers

endogenous cartel formation with heterogeneous firms in the context of an infinitely repeated capacity constrained price game we endogenize the composition of a cartel when firms are heterogeneous in their capacities when firms are sufficiently patient there exists a stable cartel involving the largest firms a firm with sufficiently small capacity is not a member of any stable cartel when a cartel is not all inclusive colluding firms set a price that serves as an umbrella with non cartel members pricing below it and producing at capacity contrary to previous work our results suggest that the most severe coordinated effects may come from mergers involving moderate sized firms rather than the largest or smallest firms

actively learning about demand and the dynamics of price adjustment by observing the quantity demanded at particular prices a firm may learn about the parameters of its demand curve in such an environment price changes obstruct the learning process by inducing additional noise the authors paper constructs a dynamic model where a price setting firm endogenously controls the speed of learning the model provides a possible explanation for price inertia as a stable pricing policy allows the firm to learn more rapidly which improves future expected profits furthermore even in the long run learning continues to affect the firm s optimal price copyright 1990 by royal economic society

looking for a guide to protect the environment the development of the precautionary principle abstract if the precautionary principle is to become the guide of the international community for environmental protection policies an economic interpretation of the principle is in order the analysis of case studies and a survey of the recent decision theoretic literature show the lack of a fully satisfactory economic model more generally various theoretical and empirical results show that the principle cannot be assumed to apply a priori though it has been proposed by international treaties as a rule of thumb for situations of scientific uncertainty the precautionary principle could actually be inefficient

systemic risk and diversification across european banks and insurers the mutual and cross company exposures to fat tail distributed risks determine the potential impact of a financial crisis on banks and insurers we examine the systemic interdependencies within and across the european banking and insurance sectors during times of stress by means of extreme value analysis while insurers exhibit a slightly higher interdependency in comparison with banks the interdependency across the two sectors turns out to be considerably lower this suggests that downside risk can be lowered through financial conglomeration

fundamental irreversibilities in stock externalities abstract this paper concerns the irreversibility effect in stock externalities in an environment of uncertainty with learning taking place one may wish to under emit today to avoid potential environmental irreversibilities alternatively one may wish to under invest in pollution control capital avoiding investments in sunk capital that turn out to be wasted the paper develops theoretical results on the tension between these two effects and separates risk aversion from the irreversibility effect the paper also presents a simple example in climate change policy

the simple economics of bank fragility banks are linked through the interbank deposit mar ket participations like syndicated loans and deposit interest rate risk the similarity in exposures carries the potential for systemic breakdowns this potential is either weak or strong depending on whether the linkages remain or vanish asymptotically it is shown that the linearity of the bank portfolios in the exposures in combi nation with a condition on the tails of the marginal distributions of these exposures determines whether the potential for systemic risk is weak or strong we show that if the exposures have marginal normal distributions the potential for systemic risk is weak while if e g the student distributions apply the potential is strong

energy prices and carbon taxes under uncertainty about global warming this paper extends the strategic interactions between producers of fossil fuels concerned about their profits and a taxing government concerned about the consumers welfare for uncertainty global warming follows an ito process stochasticity requires to differentiate between reversible and irreversible emissions in contrast to the deterministic version the unconstrained reversible case allows for a closed form solution but not the more realistic and constrained case nevertheless interesting analytical properties e g about when to stop emissions implicit conservation due to monopolistic supply are derived and complemented by a numerical example

all stage strong correlated equilibrium abstract a strong correlated equilibrium is a strategy profile that is immune to joint deviations different notions of strong correlated equilibria were defined in the literature one major difference among those definitions is the stage in which coalitions can plan a joint deviation before ex ante or after ex post the deviating players receive their part of the correlated profile in this paper we show that an ex ante strong correlated equilibrium is immune to deviations at all stages thus the set of ex ante strong correlated equilibria of moreno wooders games econ behav 17 1996 80 113 is included in all other sets of strong correlated equilibria

enlargement processes and distributional conflicts the politics of discriminatory membership in the european union this paper examines discriminatory membership in the european union from a game theoretical perspective i argue that discriminatory membership enables the enlargement of international organizations with heterogenous member states eu members impose discriminatory measures on new members to redistribute enlargement gains from new members to particularly negatively affected eu members as to render expansion pareto efficient the empirical findings of a probit analysis on the eu accession negotiations and outcomes of all five eu enlargement rounds support the theoretical claim the eu grants acceding states restricted membership rights if distributional conflicts emerge moreover the candidate s bargaining power and the possibility of alternative compensation schemes influence the enlargement outcomes

regulatory actions under adjustment costs and the resolution of scientific uncertainty food system regulators often decide whether to ban existing practices or approve new technologies without conclusive scientific evidence on possible damage and knowing that resolution is likely in the future in a model with three decision points and stochastic resolution of uncertainty we study interactions between expected losses due to regulation and information availability when a regulator is deciding on an early reversible ban and on a later reversible ban adjustment costs create inertia concerning intermediate signals such that earlier decisions are not overturned and also a bias against imposing an early ban the prospect of more later stage information can increase or decrease the incentive to ban early but research decreases the incentive to ban early

environmental prices uncertainty and learning there is an increasing demand for putting a shadow price on the environment to guide public policy and incentivize private behaviour in practice setting that price can be extremely difficult as uncertainties abound there is often uncertainty not just about individual parameters but about the structure of the problem and how to model it a further complication is the second best nature of real environmental policy making in this paper we propose some practical steps for setting prices in the face of these difficulties drawing on the example of climate change we consider how to determine the overall target for environmental protection how to set shadow prices to deliver that target and how we can learn from the performance of policies to revise targets and prices perhaps most significantly we suggest that estimates of the marginal cost of environmental protection rather than the marginal benefit will often provide the more consistent and robust prices for achieving targets

renegotiation proof equilibria in a global emission game when players are impatient in a two country model in which countries differ with respect to the perception of environmental damages and abatement costs the stability of international environmental agreements is analyzed in a dynamic framework three types of agreements are considered a socially optimal solution a uniform emission tax a tax equally applied in both countries and a uniform emission reduction quota an equal percentage emission reduction from a base year stability is checked for these agreements according to the concept of renegotiation proofness it is shown that the stability requirements depend crucially on the parameters defining the interests of the two countries and the type of agreement moreover it is demonstrated that if punishment options are restricted for some reason the stability of an agreement may suffer one important result of the paper is that if countries exhibit asymmetric interests stability in the quota regime is higher than in the tax regime and in the social optimum this might explain why emission reduction quotas have been so popular in international politics despite recommendations of economists to use market based instruments

regulation with anticipated learning about environmental damages a regulator anticipates learning about the relation between environmental stocks and economic damages for a model with linear quadratic abatement costs and environmental damages and a general learning process we show analytically that anticipated learning decreases the optimal level of abatement at a given information set if learning causes the regulator to eventually decide that damages are higher than previously thought learning eventually increases abatement learning also favors the use of taxes rather than quotas using a model that is calibrated to describe the problem of global warming we show numerically that anticipated learning causes a significant reduction in first period abatement and a small increase in the preference for taxes rather than quotas even if the regulator s initial priors about environmental damages are much too optimistic he is able to learn quickly enough to keep the expected stock trajectory near the optimal trajectory

climate change mitigation and adaptation with uncertainty and learning one of the major issues in climate change policy is how to deal with the considerable uncertainty that surrounds many of the elements some of these uncertainties will be resolved through the process of further research this process of learning raises a crucial timing question should society delay taking action in anticipation of obtaining better information or should it accelerate action because we might learn that climate change is much more serious than expected much of the analysis to date has focussed on the case where the actions available to society are just the mitigation of emissions and where there is little or no role for learning we extend the analysis to allow for both mitigation and adaptation we show that including adaptation weakens the effect of the irreversibility constraint and so for this model makes it more likely that the prospect of future learning should lead to less action now to deal with climate change we review the empirical literature on climate change policy with uncertainty learning and irreversibility and show that to date the effects on current policy are rather small though this may reflect the particular choice of models employed

learning and stock effects in environmental regulation the case of greenhouse gas emissions abstract this paper concerns the optimal regulation of greenhouse gases that lead to global climate change in particular we focus on uncertainty and learning which over time resolves uncertainty we present an empirical stochastic model of climate economy interactions and present results on the tension between postponing control until more is known vs acting now before irreversible climate change takes place uncertainty in our model is in the damage caused by global warming the results suggest that a temporary carbon tax may dominate a permanent one because a temporary tax may induce increased flexibility

united we stand or divided we stand strategic supplier alliances under order default risk we study the alliance formation strategy among suppliers in a framework with one downstream firm and n upstream suppliers each supplier faces an exogenous random shock that may result in an order default each of them also has access to a recourse fund that can mitigate this risk the suppliers can share the fund resources within an alliance but they need to equitably allocate the profits of the alliance among the partners in this context suppliers need to decide whether to join larger alliances that have better chances of order fulfillment or smaller ones that may grant them higher profit allocations we first analytically characterize the exact coalition proof nash stable coalition structures that would arise for symmetric complementary or substitutable suppliers our analysis reveals that it is the appeal of default risk mitigation rather than competition reduction that motivates cooperation in general a riskier and or less fragmented supply base favors larger alliances whereas substitutable s

coalition proof implementation abstract a new condition is shown to be necessary and sufficient for coalition proof nash equilibrium cpne implementation in environments with complete information this result implies that all choice functions are cpne implementable when individuals utility functions are bounded with respect to all variables except for money and are either analytic or quasi linear journal economic literature classification numbers c72 d72 d78

flexibility learning and irreversibility in environmental decisions a bayesian approach the bayes decision is characterized and studied for a two period decision problem involving a proposed resource development project it is assumed that development is irreversible and that expectations about benefits and costs during the second period vary with experiences resulting from the first period action the amount and types of learning achieved depend upon the particular action taken during the first period flexible sequential decision procedures are compared with fixed once and for all decisions it is shown that under this specification optimal development decisions are not necessarily more conservative when a sequential procedure is used the possibility of reneging on a fixed decision is formally specified and studied

designing climate mitigation policy this us paper provides an exhaustive review of critical issues in the design of climate mitigation policy by pulling together key findings and controversies from diverse literatures on mitigation costs damage valuation policy instrument choice technological innovation and international climate policy the authors begin with the broadest issue of how high assessments suggest the near and medium term price on greenhouse gases would need to be both under cost effective stabilization of global climate and under net benefit maximization or pigouvian emissions pricing the remainder of the paper focuses on the appropriate scope of regulation issues in policy instrument choice complementary technology policy and international policy architectures

has the financial system become safer after the crisis the changing nature of financial institution risk abstract six years after the collapse of lehman brothers the question of whether the u s financial system has become less risky remains unanswered on the one side new regulations including dodd frank and basel iii have made improvements by requiring higher bank capital and financial institutions themselves have reduced risk taking activities on the other side it has been argued that the fundamental risks remained and the efforts of regulators and politicians were simply rearranging the deckchairs on the titanic baily and elliott 2013 this paper highlights the changing nature of financial institution risk from 2005 to 2011 it finds that while these institutions have become less risky individually after the crisis the financial market has become more vulnerable to systemic contagion the causal inference that the crisis and the post crisis legislation have gradually changed the nature of financial institution risk is drawn from a quasi experimental design this finding suggests that the ever more integrated financial system might experience more synchronized contractions in future crises providing empirical support for the proposals of the inter bank collective regulation of banks by acharya 2009 in addition to the intra bank collective regulations as in froot and stein 1998 and bis 1996 1999

coalition proof nash equilibria ii applications abstract in bernheim peleg and whinston coalition proof equilibria i concepts j econ theory 42 1987 1 12 we proposed the notion of coalition proof nash equilibrium and perfectly coalition proof nash equilibrium as solution concepts for strategic environments in which players can freely discuss their strategies but cannot make binding commitments this paper undertakes applications to several economic problems including the behavior of cournot oligopolists oligopolistic entry deterrence cooperation in finite horizon games and social choice rule implementation

cooperative equilibria in finite horizon noncooperative supergames abstract it is well known that cooperative outcomes can be supported by noncooperative equilibrium strategy combinations in games that are infinitely repeated however the example of the repeated prisoner s dilemma has led people to conclude that such cooperative outcomes cannot be sustained if the game is repeated finitely often in this paper it is proved that the belief about finitely repeated games is false conditions are given that allow the existence of cooperative outcomes in finitely repeated games that are supported by subgame perfect noncooperative equilibrium strategies

a model of industrial pollution in a stochastic environment abstract standard models of pollution abatement assume that pollution accumulation occurs in a deterministic pattern as a by product of the production process governmental intervention often occurs in the form of taxation or mandatory abatement controls to reduce inefficiency caused by incomplete markets in this paper we assume that the accumulation effect of pollution may be stochastic due for instance to the random absorption capacity of the ecosystem furthermore we assume that the level of pollution may vary with input use as well as output level we proceed to analyze properties of a policy for efficient social management of competitive firms which generate pollution

uncertainty learning and heterogeneity in international environmental agreements this paper concerns the formation of international environmental agreements under uncertainty about environmental damage with different models of learning complete learning partial learning or no learning the results of the existing literature are generally pessimistic the possibility of either complete or partial learning generally reduces the level of global welfare that can be achieved from forming an iea relative to no learning that literature regards uncertainty as a parameter common to all countries so that countries are identical ex ante as well as ex post in this paper we extend the literature to the case where there is no correlation between damage costs across countries each country is uncertain about a particular parameter in our case the benefit cost ratio drawn from a common distribution but ex post each country s realized parameter value is independently drawn consequently while countries remain identical ex ante they may be heterogeneous ex post we show that this change reinforces the negative conclusions about the effects of partial learning on international environmental agreements but under certain conditions moderates the negative conclusions about the effects of complete learning

community enforcement of fisheries effort restrictions abstract this paper models the use of community sanctions to restrict effort in a simple gordon schaefer style model of the fishery with heterogeneous fishing costs the withdrawal of cooperation in other areas of life is used to both restrict effort and to sanction those who continue to cooperate with those who have not restricted effort coalition proof nash equilibria are generated by a combination of sanctions discouraging the defection of small groups and stock reductions discouraging noncooperation by large groups both entry restrictions and individual quotas can be supported by community sanctions under some parameter combinations however there are cases where each can generate lower total rents than would be available under open access relatively low cost fishers are more likely to support entry restrictions and ignore community attempts to restrict individual effort while high cost fishers are more likely to support quotas

option valuation of claims on real assets the case of offshore petroleum leases this paper extends financial option theory by developing a methodology for the valuation of claims on a real asset an offshore petroleum lease several theoretical and practical problems not present in applying option pricing theory to financial assets are addressed most importantly we show the necessity of combining option pricing techniques with a model of equilibrium in the market for the underlying asset petroleum reserves the advantages of this approach over conventional discounted cash flow techniques are emphasized the methodological development provides important insights for both company behavior and government policy promising empirical results are reported

informational benefits of international treaties international treaties allow a minister in one country to learn about the beliefs held by a minister in another country so allowing each to make better decisions when the net benefits of environmental policy are uncertain a country which participates in negotiating an environmental treaty or which supports strong environmental action thereby provides information to another country that such action can be worthwhile this dimension of international environmental agreements helps explain why countries negotiate treaties why these treaties often implement the nash non cooperative equilibrium why agreement to a treaty by a country deemed not particularly favorable to it can strengthen environmental action and why treaties may invoke a minimum participation clause the informational mechanism we discuss holds even if physical spillovers are absent and even if monitoring and enforcement are infeasible our approach can explain additional phenomena how requirements for approval by several bodies within a country can increase support for a policy and why simultaneous action can lead to better outcomes than sequential action

investment in risky r d programs in the face of climate uncertainty we analyze how the socially optimal technology rd and that uncertainty in damages interacts with uncertainty in the returns to rd and r d that reduces the emissions to output ratio and argue that this is a good representation of r d into fossil fuel technologies for r d programs into non carbon technologies optimal investment is higher in riskier programs our empirical model indicates that the optimal investment in a risky program is about 3 1 2 times larger than in a program with certain returns for r d programs aimed at reducing emissions in fossil fuel based technologies our results show that qualitatively investment is higher in less risky programs under most uncertain damage scenarios our empirical model shows however that the risk profile of fossil fuel based r d programs generally has little quantitative impact on optimal investment the exception is that when the probability of a catastrophe inducing full abatement is very high investment is about twice as high in risky programs compared to programs with certain returns

coordination and bargaining power in contracting with externalities abstract building on genicot and ray g genicot d ray contracts and externalities how things fall apart j econ theory 131 2006 71 100 we develop a model of non cooperative bargaining that combines the two main approaches in the literature of contracting with externalities the offer game in which the principal makes simultaneous offers to the agents and the bidding game in which the agents make simultaneous offers to the principal allowing for agent coordination we show that the outcome of our bargaining procedure may differ remarkably from those of the offer and the bidding games in particular we find that bargaining can break agents coordination and that the principal s payoff can be decreasing in his own bargaining power

the right type of legislator a theory of taxation and representation abstract we develop a theory of taxation and the distribution of government spending in a citizen candidate model of legislatures individuals are heterogeneous in two dimensions productive ability in the private sector and negotiating ability in politics when these are positively correlated rich voters always prefer a rich legislator but poor voters face a trade off a rich legislator will secure more pork for the district but will also prefer lower taxation than the poor voter our theory organizes a number of stylized facts across countries about taxation and redistribution parties and class representation in legislatures we demonstrate that spending does not necessarily increase when the number of legislators increases as the standard common pool intuition suggests and that many policies aimed at increasing descriptive representation may have the opposite effect

global warming endogenous risk and irreversibility this paper develops two period analytical and numerical models to study the question given a stock of greenhouse gases that poses a risk of future damages of unknown magnitude and the possibility of learning about damages how do sunk abatement capital and a nondegradable stock of greenhouse gases affect optimal first period investment we show that both affect investment the former negatively and the latter positively additionally endogenous risk the risk of damages dependent on the stock of gases results in an increase in optimal investment for any level of capital sunkness or greenhouse gas degradability quantitatively the effect of sunk capital is stronger than the effect of greenhouse gas irreversibility or that of endogenous risk

stabilizing greenhouse gas emissions assessing the intergenerational costs and benefits of the kyoto protocol the costs and benefits current and future generations incur as the result of climate change or an environmental control policy are often confounded with other objectives such as generational discounting or optimal policy design this paper uses a consumption equivalent measure to simulate the loss or gain of consumption independent of these confounding objectives the findings suggest that the costs associated with an emissions stabilization program are relatively large for current generations and continue to increase over the next 100 years the first generation to actually benefit from the stabilization program is born early during the 24th century

citicorp travelers group merger challenging barriers between banking and insurance abstract the citicorp travelers group merger increased the prospects for new legislation to remove the barriers between banking and insurance resulting in a positive wealth effect for institutions most likely to gain from deregulation analysis of abnormal returns surrounding the merger show that life insurance companies and large banks excluding citicorp and travelers group have significant stock price increases while the returns of small banks health insurers and property casualty insurers are insignificantly different from 0 this analysis provides evidence that investors expect large banks and insurance companies to receive significant benefits from recent congressional legislation removing barriers to bancassurance

lock in effect of emission standard and its impact on the choice of market based instruments abstract a country s existing emission standard policy will lead to a lock in effect when the country plans to adopt new market based instruments to control greenhouse gas emissions it must consider this effect as it chooses among instruments to avoid larger efficiency loss in this paper we find that the lock in effect will cause a kink point to occur on the marginal abatement cost mac curve this change of shape for the mac curve reminds us to be cautious in choosing market based instruments when applying weitzman s rule we also introduce this concept into a dynamic multi regional computable general equilibrium cge model for china and simulate mac curves for all regions after applying weitzman s rule we propose a timeline for introducing price instruments under different marginal benefit mb curve scenarios

information and the dynamics of environmental protection the concept of the critical period earlier work on environmental decisions under uncertainty is extended from two periods to many permitting treatment of a richer variety of problems implications for pollution control policy of several different kinds of ecosystem recovery dynamics are considered in the context of improving information about ecosystem behavior and preferences for environmental goods multiperiod analogs of the two period concept of quasi option value are developed

targets for global climate policy an overview a survey of the economic impact of climate change and the marginal damage costs shows that carbon dioxide emissions are a negative externality the estimated pigou tax and its growth rate are too low to justify the climate policy targets set by political leaders a lower discount rate or greater concern for the global distribution of income would justify more stringent climate policy but would imply an overhaul of other public policies catastrophic risk justifies more stringent climate policy but only to a limited extent

costs of reducing global carbon emissions po rojecting the costs of reducing carbon emissions is extremely important and exceedingly difficult such projections are an integral component of cost benefit analyses of alternative policies for example for the global climate policy analysis described by william nordhaus in this symposium moreover the nature of the climate change problem dictates that costs be incurred long before benefits can be realized or accurately measured consequently the political spotlight predictably focuses on the cost estimates whenever specific policy options are contemplated projecting the costs of reducing carbon emissions is difficult because many assumptions must be made about how the world will evolve over a very long period of time with and without a control program typically some of these assumptions like population growth are taken from outside sources other factors like the response of energy demand to changes in economic output or energy prices are the result of modeling the behavior of economic actors in response to exogenous stimuli considerable uncertainty exists about both the exogenous factors and the best way to model the behavioral responses the global nature of the climate change problem adds yet another complication to the cost analysis scientists have concluded that it is the global concentration of carbon in the atmosphere that influences climate moreover since carbon in the atmosphere gets mixed more or less uniformly emissions anywhere change concentrations everywhere but with a long lead time current global carbon emissions are estimated to be only about 4 percent of the stock of co2 in the atmosphere attributable to human activity and about

dynamic public goods provision with coalitional manipulation abstract we study dynamic procedures for the provision of an efficient level of a public good with time dependent surplus distribution in general such procedures are prone to manipulation via pre play communication among coalitions of agents we begin with a generalization of truchon s econometrica 1984 52 1179 1190 elegant non myopic mdp procedure and provide a new procedure that exhibits finite monotone convergence to pareto efficiency in subgame perfect coalitionproof equilibrium this procedure also implements any regular surplus distribution rule that is dependent on the public good level the solution concept of subgame perfect coalition proof equilibrium is also new it is an extension of the semistability characterizations of coalition proof equilibrium for infinite strategy games due to kahn and mookherjee games and economic behavior 1992 4 101 121 the coalition proofing device given is more generally applicable

specifications of social welfare in economic studies of climate policy overview of criteria and related policy insights an important assumption in economic studies of climate policy is the social welfare function this paper shows that applying distinct decision or social welfare criteria can result in different optimal policies of climate control notably if climate change impacts are uncertain first decision criteria in current climate economic studies are reviewed next the most important alternatives are discussed including their mathematical formalization and incorporation in economy climate models most of these alternative criteria suggest more stringent climate policies to be optimal than the standard discounted utilitarianism approach however several important welfare criteria have not or hardly seen any application in the economic analysis of climate policy we conclude that there is clear need for systematic research on this theme for which the current review provides a solid basis

equilibrium coordination with discretionary policy making discretionary policymakers cannot manage private sector expectations and cannot coor dinate the actions of future policymakers as a consequence coordination failures can occur and multiple equilibria can arise in this paper we employ notions of self enforceability and learnability to motivate and identify equilibria of particular interest in discretionary policy problems exhibiting multiple equilibria central among these criteria are whether an equilib rium is robust to the formation of coalitions and whether it is learnable by private agents and jointly learnable by private agents and the policymaker unless the pareto preferred equilibrium is learnable by private agents we find little reason to expect coordination on that equilibrium

electric sector capacity planning under uncertainty climate policy and natural gas in the us abstract this research investigates the dynamics of capacity planning and dispatch in the us electric power sector under a range of technological economic and policy related uncertainties using a two stage stochastic programming approach model results suggest that the two most critical risks in the near term planning process of the uncertainties considered here are natural gas prices and the stringency of climate policy stochastic strategies indicate that some near term hedging from lower cost wind and nuclear may occur but robustly demonstrate that delaying investment and waiting for more information can be optimal to avoid stranding capital intensive assets hedging strategies protect against downside losses while retaining the option value of deferring irreversible commitments until more information is available about potentially lucrative market opportunities these results are explained in terms of the optionality of investments in the electric power sector leading to more general insights about uncertainty learning and irreversibility the stochastic solution is especially valuable if decision makers do not sufficiently account for the potential of climate constraints in future decades or if fuel price projections are outdated

strategic behavior institutional change and the future of agriculture policy reforms that increase the roles of markets in agriculture and related institutional changes are occurring worldwide and are accompanied by rapid technical change with the evolving role of government new institutions are emerging for shaping the strategic behavior of public and private sector agents this paper suggests that the use of game theoretic formulations combined with modern concepts of mechanism design offers an approach to policy analysis and the study of institutional change that is valuable to professionals involved in the economics of agriculture

uncertainty learning and international environmental agreements the role of risk aversion this paper analyses the formation of international environmental agreements ieas under uncertainty learning and risk aversion it bridges two strands of the iea literature i the role of learning when countries are risk neutral ii the role of risk aversion under no learning combining learning and risk aversion seems appropriate as the uncertainties surrounding many international environmental problems are large often highly correlated e g climate change but are gradually reduced over time through learning the paper analyses three scenarios of learning a key finding is that risk aversion can change the ranking of these three scenarios of learning in terms of welfare and membership in particular the negative conclusion about the role of learning in a strategic context under risk neutrality is qualified when countries are significantly risk averse then it pays them to wait until uncertainties have been largely resolved before joining an iea this may suggest why it has been so difficult to reach an effective climate change agreement

do financial conglomerates create or destroy value evidence for the eu there is an ongoing debate about whether firm focus creates or destroys shareholder value earlier literature has shown significant diversification discounts firms that engage in multiple activities are valued lower various factors are important in determining the size of the discount for example cross subsidization and agency problems the existing literature however generally focuses on non financial firms or on banks combining investment and commercial banking our paper focuses specifically on the valuation of bank insurance conglomerates we find no universal diversification discount but significant variability the discount is explained by the size increasing the familiarity with the conglomerate business model decreasing and the risk profile decreasing our results are robust to the historical origin the merger record and the age of the conglomerate as well as peer group specification and outlier elimination

asset market linkages in crisis periods we characterize asset return linkages during periods of stress by an extremal dependence measure contrary to correlation analysis this nonparametric measure is not predisposed toward the normal distribution and can allow for nonlinear relationships our estimates for the g 5 countries suggest that simultaneous crashes between stock markets are much more likely than between bond markets however for the assessment of financial system stability the widely disregarded cross asset perspective is particularly important for example our data show that stock bond contagion is approximately as frequent as flight to quality from stocks into bonds extreme cross border linkages are surprisingly similar to national linkages illustrating a potential downside to international financial integration

environmental regulation with technology adoption learning and strategic behavior we analyze a model of environmental regulation with learning about environmental damages and endogenous choice of emissions abatement technology by a polluting firm we compare environmental policy under discretion in which policy is updated upon learning new information versus under rules in which policy is not updated when investment in abatement technology is made prior to the resolution of uncertainty neither discretion nor rules with either taxes or standards achieve an efficient solution except in special cases when there is little uncertainty rules are superior to discretion because discretionary policy gives the firm an incentive to distort investment in order to influence future regulation however when uncertainty is large discretion is superior to rules because it allows regulation to incorporate new information taxes are superior to standards under discretion regardless of the relative slopes of marginal costs and marginal damages for the case of quadratic abatement costs and damages