prices or quantities can dominate banking and borrowing the possibility of intertemporal banking and borrowing of tradable permits is often viewed as tilting the various policy debates about optimal pollution control instruments towards favoring such time flexible quantities this paper shows that this view can be misleading at least for the simplest dynamic extension of the original prices versus quantities information structure the model of this paper allows firms to know and act upon the realization of uncertain future costs two full periods ahead of the regulators for any given circumstance the paper shows that either a fixed price or a fixed quantity is superior in expected welfare to time flexible banking and borrowing furthermore the standard original formula for the comparative advantage of prices over quantities contains sufficient information to completely characterize the regulatory role of intertemporal banking and borrowing the logic and implications of these results are analyzed and discussed

linking permit markets multilaterally we formally study the determinants magnitude and distribution of efficiency gains generated in multilateral linkages between permit markets we provide two novel decomposition results for these gains characterize individual preferences over linking groups and show that our results are largely unaltered with strategic domestic emissions cap selection or when banking and borrowing are allowed using the paris agreement pledges and power sector emissions data of five countries which all use or considered using both emissions trading and linking we quantify the efficiency gains we find that the computed gains can be sizable and are split roughly equally between effort and risk sharing

bankable permits for the control of environmental pollution abstract intertemporal trading of emission permits banking is often identified as one of three promising market mechanisms for controlling pollution along with averaging and trading surprisingly the efficiency properties of permit banking systems have not been investigated using a simple optimal control model this paper investigates firms incentives for banking or borrowing emission permits and compares the emission and output streams firms would choose with the socially optimal solution we find that in many cases firms will suboptimally choose excessive damage and output levels in early periods and correspondingly too few in later periods if given the opportunity to freely move emissions between time periods we propose a simple alternative trading scheme we term modified banking that counters this problem and should be no more difficult for an environmental authority to implement than a straigth banking system

losses from effluent taxes and quotas under uncertainty recent theoretical papers by adar and griffin j environ econ manag 3 178 188 1976 fishelson j environ econ manag 3 189 197 1976 and weitzman rev econ studies41 477 491 1974 show that different expected social losses arise from using effluent taxes and quotas as alternative control instruments when marginal control costs are uncertain key assumptions in these analyses are linear marginal cost and benefit functions and an additive error for the marginal cost function to reflect uncertainty in this paper empirically derived nonlinear functions and more realistic multiplicative error terms are used to estimate expected control and damage costs and to identify empirically the mix of control instruments that minimizes expected losses

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

fiscal interactions and the case for carbon taxes over grandfathered carbon permits this paper provides simple formulas for adjusting the costs of carbon taxes and tradable carbon permits to account for interactions with pre existing tax distortions in the labour market both policies reduce labour supply as they increase product prices and reduce real household wages the resulting efficiency losses in the labour market can be substantial relative to partial equilibrium abatement costs however much of this added cost can be offset and perhaps more than offset when additional distortions from the tax system are considered if revenues from carbon taxes or auctioned permits are used to reduce distortionary taxes consequently there can be a strong case on efficiency grounds for using carbon taxes or auctioned permits over grandfathered carbon permits copyright 2003 oxford university press

climate policy design with correlated uncertainties in offset supply and abatement cost emission offsets within cap and trade systems are widely believed to contain system costs and stabilize allowance prices however trends in offsets supply are uncertain may be persistent and may be correlated with other sources of uncertainty in a dynamic stochastic model we find total costs increase as does variability in allowance prices and emissions as uncertainty in offsets becomes more persistent and to a lesser extent becomes negatively correlated with uncertainty in abatement costs these results are amplified with risk sensitivity larger annual offset limits and competitive offset purchasing imposing an allowance price collar can mitigate cost increases and price variability jel q54 q58

correlated uncertainty and policy instrument choice abstract for two decades environmental economists have generally maintained that benefit uncertainty is irrelevant for choosing between price and quantity instruments but that cost uncertainty matters with the identity of the efficient instrument depending upon the relative slopes of the marginal benefit and cost functions but in the presence of simultaneous correlated uncertainty such policy instrument recommendations may be inappropriate with plausible values of relevant parameters the conventional identification of a price instrument will be reversed to favor instead a quantity instrument the opposite reversal from the choice of a quantity instrument to a price instrument seems less likely to occur

can decentralized planning really achieve first best in the presence of environmental spillovers abstract it is generally accepted that decentralized policy choice in the presence of interjurisdictional spillovers is inefficient strikingly ogawa and wildasin 2009 find that in a model with heterogenous jurisdictions interjurisdictional capital flows and interjurisdictional environmental damage spillovers decentralized planning outcomes are equivalent to that under a centralized planner we first show the critical importance of two key assumptions no retirement of capital fixed environmental damages per unit of capital in obtaining this result second we consider a more general model allowing for capital retirement and abatement activities and show that the outcome of a decentralized market generally differs from the solution of a centralized planner s social welfare maximizing problem

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

the economics of controlling stock pollutants an efficient strategy for greenhouse gases abstract optimal control theory is applied to develop an efficient strategy to control stock pollutants such as greenhouse gases and hazardous waste the optimal strategy suggests that at any time the marginal costs of abatement should be equated with the present value of the marginal damage of timely unabated emission the optimal strategy calls for increasingly light abatement over time as the pollutant stock accumulates the optimal policy applied to greenhouse gases suggests moderate abatement efforts at present with the potential for much greater future efforts

the problem of the commons still unsettled after 100 years the problem of the commons is more important to our lives and thus more central to economics than a century ago when katharine coman led off the first issue of the american economic review as the us and other economies have grown the carrying capacity of the planet in regard to natural resources and environmental quality has become a greater concern particularly for commonproperty and open access resources the focus of this article is on some important unsettled problems of the commons within the realm of natural resources there are special challenges associated with renewable resources which are frequently characterized by open access an important example is the degradation of openaccess fisheries critical commons problems are also associated with environmental quality a key contribution of economics has been the development of market based approaches to environmental protection these instruments are key to addressing the ultimate commons problem of the twenty first century global climate change jel q15 q21 q22 q25 q54

pandemics and the environmental rebound effect reflections from covid 19 the irruption of the covid 19 pandemic has raised concerns on sustainability issues the pandemic has accelerated the implementation of technologies such as ict and shifts in mobility behaviour such changes have the potential to reduce environmental burdens but also to trigger large environmental rebound effects this perspective article reflects on some emerging concerns on the socio economic effects of a pandemic on the environment from a rebound effect perspective although the pandemic offers potential to improve the environmental conditions it brings also a high risk to produce jevons paradox i e increase environmental burdens rather than decrease them as initially expected governments should be aware of these risks and assess the possibility to implement additional measures like environmental taxation or limiting the use of resources to help achieving sustainability targets

long term environmental problems and strategic intergenerational transfers the impacts of long lived stock pollutants and the measures supposed to address them link current and future generations altruism towards successor generations is a prerequisite for resolving the resulting intergenerational equity issues preference asymmetry and imperfect altruism introduce strategic conflicts between generations here a current generation decides on a combination of abatement and whether to provide an imperfect backstop the future generation decides whether to use the backstop or not we identify three outcomes 1 technology denial in which the current generation deliberately rejects the imperfect backstop to avoid misuse by the future generation 2 underabatement in which the current generation provides the backstop but reduces abatement activities and 3 overabatement in which the current generation provides the backstop but increases abatement activities the outcome depends non trivially on the assessment of collateral damages of the future generation uncertainty over future preferences renders technology denial more likely corresponding author bergheimer str 20 69115 heidelberg germany goeschl eco uni heidelberg de

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

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

emissions trading systems with cap adjustments abstract emissions trading systems etss with fixed caps lack provisions to address systematic imbalances in the supply and demand of permits due to changes in the state of the regulated economy we propose a mechanism which adjusts the allocation of permits based on the current bank of permits the mechanism spans the spectrum between a pure quantity instrument and a pure price instrument we solve the firms emissions control problem and obtain an explicit dependency between the key policy stringency parameter the adjustment rate and the firms abatement and trading strategies we present an analytical tool for selecting the optimal adjustment rate under both risk neutrality and risk aversion which provides an analytical basis for the regulator s choice of a responsive ets policy

combining price and quantity controls to mitigate global climate change abstract uncertainty about compliance costs causes otherwise equivalent price and quantity controls to behave differently and leads to divergent welfare consequences although most of the debate on global climate change policy has focused on quantity controls due to their political appeal this paper argues that price controls are more efficient simulations based on a stochastic computable general equilibrium model indicate that the expected welfare gain from the optimal price policy is five times higher than the expected gain from the optimal quantity policy an alternative hybrid policy combines both the political appeal of quantity controls with the efficiency of prices using an initial distribution of tradeable permits to set a quantitative target but allowing additional permits to be purchased at a fixed trigger price even sub optimal hybrid policies offer dramatic efficiency improvements over otherwise standard quantity controls for example a 50 trigger price per ton of carbon converts the 3 trillion expected loss associated with a simple 1990 emission target to a 150 billion gain these results suggest that a hybrid policy is an attractive alternative to either a pure price or quantity system

an international policy architecture for the post kyoto era in february 2005 the kyoto protocol to the united nations framework convention on climate change came into force but without participation by the united states its impacts on emissions of greenhouse gases including carbon dioxide co2 the primary anthropogenic driver of climate change will be trivial but scientific robert t watson 2001 and economic charles d kolstad and michael a toman 2001 analyses point to the need for a credible international approach because the kyoto protocol s ambitious targets apply only to the short term 2008 2012 and only to industrialized nations the agreement will impose relatively high costs and generate only modest short term benefits while failing to provide a real solution joseph e aldy et al 2003 for these reasons most economists see the agreement as deeply flawed richard n cooper 1998 david g victor 2001 warwick j mckibbin and peter j wilcoxen 2002 although some see it as an acceptable first step axel michaelowa 2003 virtually all agree however that the protocol is not sufficient to the overall challenge we describe the basic features of a postkyoto international global climate agreement which addresses three crucial questions who when and how the respective elements are first a means to ensure that key nations industrialized and developing are involved second an emphasis on an extended time path of action employing a cost effective pattern over time and third inclusion of market based policy instruments i who expand participation to include all key countries

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

selecting sustainable renewable energy source for energy assistance to north korea abstract renewable energy re is the best sustainable energy solution south korea can provide to assist north korea in overcoming its chronic energy shortage designed as a follow on research to sin et al 1 a survey was conducted with a panel of experts consisting of various disciplines and affiliations using the analytic hierarchy process ahp with benefit opportunity cost and risk bocr the results showed the panel viewed security as the most important factor among the strategic criteria for the level 1 attributes the panel showed no significant differences of opinion among the different alternatives however cost showed to be the most important factor for the panel the panel chose wind power as the best alternative source of energy for north korea however there were some differences in opinion among the sub groups of the panel depending on the composition and the expertise of the sub group compared to other studies on the similar topic this research stands out in that the research results were derived using ahp and bocr and that the panel was composed of both korean and foreign experts on north korea affiliated with state run research organizations armed forces non governmental organizations academic research organizations private consulting firms and journalism the research arrived at the conclusion that the following factors must be considered as south korea designs its future north korean energy assistance policy 1 re assistance for north korea can take on various forms hence experts consulted during the design writing and implementation phases of the policy in question must possess knowledge and expertise in the appropriate technology and methodology being considered 2 possibility of a sudden destabilization of the northeast asian security paradigm due to the collapse of north korea and 3 continued nuclearization of north korea

cooperation on climate change mitigation abstract we analyze conditions under which it is possible to achieve efficient mitigation of greenhouse gas emissions with a self enforcing international agreement in which all countries find it in their self interest to abide by the agreement we model the choice of emissions by countries as a dynamic game we use a two part punishment scheme for deviations from an agreement that is renegotiation proof and show when this scheme supports the efficient outcome as a subgame perfect equilibrium using numerical examples we show that an efficient subgame perfect equilibrium exists for a range of reasonable parameter values the existence of such equilibrium may be non monotonic in the discount rate and the ratio of slope of marginal abatement cost and marginal damages

pollution standards vs charges under uncertainty conventional analysis of pollution control policy under uncertainty does not properly account for the potential cost effectiveness difference between standards and charges thus drawing misleading conclusions for the case of inefficient standards correcting for this anomaly the following conclusions can be drawn when uncertainty involves the position of the marginal damage cost schedule rather than policy indifference a charge is always superior to an inefficient standard when uncertainty is about the position of the marginal control cost schedule policy indifference may occur but if it does it must be the case that the slope of marginal damage cost exceeds that of marginal control cost

the welfare effects of allowance banking in emissions trading programs permitting allowance banking in emissions trading programs can reduce expected compliance costs by giving capped firms flexibility to adjust the time path of abatement and to hedge against future uncertainty recent literature suggests that this compliance cost dividend is significant fell and morgenstern environ resour econ 47 275 297 2010 allowance banking may yield an environmental dividend a if the growth rate of marginal damages from emissions is less than the discount rate and b if emissions are lower in the short run as firms bank permits for use in later periods a discrete stochastic dynamic programming model is considered to simulate the two dividends of allowance banking in the context of the most recent federal united states greenhouse gas cap and trade legislation simulation results show that under a range of parameter values the environmental dividend has the same order of magnitude as the compliance cost dividend under the central set of parameters allowance banking increases expected present value of benefits by about 350 million dollars per year of the program the environmental dividend however is completely eliminated if capped firms can borrow permits from future periods without limit

pollution permit markets with intertemporal trading and asymmetric information abstract we consider the problem of determining the permit discount rate in pollution permit markets in which permits may be traded over time and polluting firms have better information about their abatement costs than does the regulator we show that the preferred permit discount rate may be greater than or less than the money discount rate we also consider whether or not the regulator should allow intertemporal trading to take place allowing intertemporal trading lowers social costs when the slope of the marginal damage function is less than the slope of the aggregate marginal abatement cost function

tax versus quota regulation a stochastic model of the fishery in a deterministic setting it has been demonstrated that taxes and quotas can be equivalent regulatory instruments and that both can in principle induce an optimal allocation of resources in markets where externalities are problematic in this paper we consider growth harvest and demand uncertainty within the context of canada s pacific halibut fishery and find that while taxes remain the preferred instrument the welfare losses arising from the use of individual boat quotas are minor

taxes and quotas for a stock pollutant with multiplicative uncertainty we compare taxes and quotas when firms and the regulator have asymmetric information about the slope of firms abatement costs damages are caused by a stock pollutant we calibrate the model using cost and damage estimates of greenhouse gasses taxes dominate quotas as with additive uncertainty this model with multiplicative uncertainty allows us to compare expected stock levels under the two policies and to investigate the importance of stock size and the magnitude of uncertainty on the policy ranking

estimates of the costs of kyoto marrakesh versus the mckibbin wilcoxen blueprint in this paper we update our earlier estimates of the cost of the kyoto protocol using the g cubed model taking into account the new sink allowances from recent negotiations as well as allowing for multiple gases and new land clearing estimates we then compare the protocol to an alternative policy outlined in mckibbin et al brookings policy brief no 17 june the brookings institution washington 1997 climate change policy after kyoto a blueprint for a realistic approach the brookings institution washington 2002a j econom perspect 16 2 2002b 107 that does not impose rigid emissions targets we focus particular attention on the sensitivity of compliance costs under each policy to unexpected changes in future economic conditions to illustrate the issue we evaluate the policies under two plausible alternative assumptions about a single aspect of the future world economy the rate of productivity growth in russia we find that moderate growth in russia would raise the cost of the kyoto protocol by as much as 50 percent but would have little effect on the cost of the alternative policy we conclude that the kyoto protocol is inherently unstable because unexpected future events could raise compliance costs substantially and place enormous pressure on governments to abrogate the agreement the alternative policy would be far more stable because it does not subject future governments to adverse shocks in compliance costs

uncertainty and pollution the role of indirect taxation abstract this paper explores the potential usefulness of indirect taxation as a supplement to effluent charges it is argued that effluent charges should typically be accompanied by taxes on privately traded commodities linked to the pollutant in consumption or production the performance of such combinations of taxes and charges is then compared to that of an effluent standard

the role of economics in climate change policy many policy problems have frustratingly long histories of inefficient regulation that can be difficult or impossible to reverse even where large efficiency gains might be had from doing so climate change is an exception however because little real action has been undertaken to date it presents an unusual opportunity for an efficient economic policy to be employed right from the beginning however the opportunity could easily be lost ongoing negotiations conducted under the auspices of the united nations framework convention on climate change have so far produced the kyoto protocol a deeply flawed agreement that manages to be both economically inefficient and politically impractical in this article we examine the key economic characteristics of climate change and argue that economic theory provides good guidance on the design of an efficient and politically realistic policy because climate change involves vast uncertainties and has potentially enormous distributional effects neither of the standard market based environmental policy instruments is a viable approach a tradable permit system would be inefficient and an emissions tax would be politically unrealistic however a hybrid policy combining the best features of the two would be an efficient and practical approach we then compare our hybrid proposal to the kyoto protocol and argue that it overcomes the protocol s shortcomings

indirect methods for regulating externalities under uncertainty it is sometimes necessary or appropriate to correct an externality by intervening in the market for a privately traded commodity with which the externality is linked in these situations ad valorem taxation is a viable policy option it is argued that some combination of specific and ad valorem taxes will always outperform regulations which fix price administratively but that quantity standards may outperform taxes the analysis is applied to a problem in international trade

designing carbon markets part ii carbon markets in space this paper analyses the design of carbon markets in time i e intertemporally it is part of a twin set of papers that ask starting from first principles what an optimal global carbon market would look like by around 2030 our focus is on firm level cap and trade systems although much of what we say would also apply to government level trading and carbon offset schemes we examine the first principles of temporal design that would help to maximise flexibility and to minimise costs including banking and borrowing and other mechanisms to provide greater carbon price predictability and credibility over time

dynamic taxes and quotas with learning we compare dynamic taxes and quotas when a regulator and non strategic firm have asymmetric information the regulator learns by using either a tax or a quota that can be slack with a tax the information asymmetry is resolved in one period optimal learning using a quota is less transparent but we show that learning never takes place gradually in the first period the regulator either acts myopically or he tries to improve his information but he never experiments in subsequent periods we use this result to assess the informational advantage of taxes compared to quotas under asymmetric information

quantifying the net cost of a carbon price floor in germany abstract the german energy and climate policy mix is failing to decarbonize electricity production until now with only 6 overall co2 emissions reductions since 2005 using empirical methods and hourly market data we estimate the aggregate supply curve of the german power market and simulate the effect of a 20 tco2 and 40 tco2 carbon price floor on the german power market and on the renewable subsidy scheme with the 40 tco2 carbon price floor median prices increase by 37 mwh and average price peaks by 50 mwh at the wholesale level the market s annual volume increases by some 18 billion to 39 billion at the retail level however the net cost to consumers is moderated due to costs savings from the renewable subsidy scheme worth some 4 billion or roughly one fifth the same ratio applies to a price floor at 20 tco2

alternative approaches to cost containment in a cap and trade system we compare several emissions reduction instruments including quantity policies with banking and borrowing price policies and hybrid policies safety valve and price collar using a dynamic model with stochastic baseline emissions the instruments are compared under the design goal of obtaining the same expected cumulative emissions across all options based on simulation analysis with the model parameterized to values relevant to proposed us climate mitigation policies we find that restrictions on banking and borrowing including the provision of interest rates on the borrowings can severely limit the value of the policy depending on the regulator chosen allowance issuance path although emissions taxes generally provide the lowest expected abatement costs a cap and trade system combined with either a safety valve or a price collar can be designed to provide expected abatement costs near those of a tax but with lower emissions variance than a tax consistently a price collar is more cost effective than a safety valve for a given expected cumulative emissions outcome because it encourages inexpensive abatement when abatement costs decline

automobile externalities and policies this paper discusses the nature and magnitude of externalities associated with automobile use including local and global pollution oil dependence traffic congestion and traffic accidents it then discusses current federal policies affecting these externalities including fuel taxes fuel economy and emissions standards and alternative fuel policies summarizing insofar as possible the welfare effects of those policies finally we discuss emerging pricing policies including congestion tolls and insurance reform and summarize the appropriate combination of policies to address automobile externalities

optimal exploitation and enhancement of environmental resources abstract this work is an analysis of the problem of the optimal utilization of environmental resources where both the renewable resource exploitation problem and the pollution control problem are placed in a general context of exploitation and enhancement of environmental resources the contribution of this work is to clarify the conditions for the existence of an optimal trajectory for the stationary environmental resource stock in terms of the functional forms of environmental enhancement activities and the indigenous growth rate function of environmental resources also three new economic insights gained from the analysis are presented

discounting inside the washington d c beltway places more weight on costs and benefits in the near term over costs and benefits in the future the choice of the discount rate is therefore critical in evaluating the merits of many public policy proposals this article focuses on how the choice of discount rate can dramatically affect policy choices these policies include whether to build a bridge whether to privatize a power marketing administration which sells electricity generated by government owned facilities such as dams how much money should be spent on early childhood education or options for reforming social security the ongoing challenge is to discount future costs or benefits in a way that matches the project s level of riskiness we begin by discussing the underlying issues in choosing an appropriate discount rate we then discuss the variety of different discount rates that are actually used by various washington policymakers and the biases they often generate

landing fees vs harvest quotas with uncertain fish stocks a revised version of this paper was published in the journal of environmental economics and management volume 43 issue 2 march 2002 pages 325 338

controlling stock externalities in a common property fishery subject to uncertainty abstract two methods are examined for regulating stock externalities under uncertainty quotas and taxes dynamic programming is used to characterize the externalities precisely the accuracy with which the current size of the resource stock can be monitored is found to be of crucial importance in the choice between tax and quota regulation if the current stock is observed without error taxes are capable of outperforming any quota

optimal trading ratios for pollution permit markets abstract we demonstrate a novel method for improving the efficiency of pollution permit markets by optimizing the exchange of emissions through trade under full information it is optimal for emissions to exchange according to the ratio of marginal damages under asymmetric information we derive necessary conditions for the marginal damage trading ratios to be optimal illustrate that the marginal damage trading ratios are generally not optimal and show how to improve efficiency using optimal trading ratios we calculate the optimal trading ratios for a global carbon market the gains from using optimal trading ratios rather than marginal damage trading ratios range from substantial to trivial which suggests the need for careful consideration of asymmetric information when designing permit markets