monetary policy asset prices and liquidity in over the counter markets we develop a model where agents can allocate their wealth between a liquid asset which can be used to purchase consumption goods and an illiquid asset which represents a better store of value should a consumption opportunity arise agents may visit a frictional over the counter secondary asset market where they can exchange illiquid for liquid assets we characterize how monetary policy affects both the issue price and the secondary market price of the asset we also show that in contrast to conventional wisdom search and bargaining frictions in the secondary asset market can improve welfare if inflation is low

the weitzman price corner abstract the standard theoretical approach to comparing price and quantity policies is strictly interior we extend the comparison to account for the possibility of corner outcomes where a polluting industry responds to a tax by abating either completely or not at all we show that when the uncertainty in marginal costs is high the inclusion of corner outcomes confers an extra and unnoticed advantage upon an emissions tax in situations where the standard approach would recommend a quantity policy the possibility of corners can reverse that recommendation

using a policy mix for pollution control a review of economic literature this article provides a review of economic studies analyzing the use of multiple policies a socalled policy mix to cope with single pollution problems to guide and structure the review an analytical framework is developed and applied the framework integrates transaction costs into the analysis of pollution problems and policies to overcome them moreover it understands a pollution externality not only as a market failure but more generally as the failure of private governance structures based on this insight two rationales for using a policy mix are identified first a policy mix may help to correct for multiple reinforcing failures of private governance structures such as pollution externalities and technological spillovers second a policy mix can be employed if the implementation of single first best policies brings about high transaction costs e g when marginal pollution damages are heterogeneous or polluters are unlikely to comply with the policy for each rationale the relevant literature is presented based on the review avenues for future research are identified

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

a note on emissions taxes and incomplete information in contrast with what we perceive is the conventional wisdom about setting a second best emissions tax to control a uniformly mixed pollutant under uncertainty we demonstrate that setting a uniform tax equal to expected marginal damage is not generally efficient under incomplete information about firms abatement costs and damages from pollution we show that efficient taxes will deviate from expected marginal damage if marginal damage is increasing and there is uncertainty about the slopes of the marginal abatement costs of regulated firms moreover tax rates will vary across firms if a regulator can use observable firm level characteristics to gain some information about how the firms marginal abatement costs vary

rent creation and rent seeking in environmental policy rents and political motives are present in many aspects of public policy this article considers the role of rents rent seeking and the political choice of environmental policy rents are introduced into the political choice of price and quantity regulation under conditions of uncertainty the model shows how political economy aspects affect the choice between price and quantity regulation the contesting of rents associated with different policies affects the regulatory structure and influences the political choice of an environmental policy target the primary conclusion is that the political choice of environmental policy depends on the interaction between the efficiency of rent transfer and the size of rent seeking groups within the economy

precautionary principle and the optimal timing of environmental policy under ambiguity i consider a problem in environmental policy design in which i focus on stock pollutants in particular i consider stock pollutants that cause severe damage on the environment and do not depreciate at all once they are released into the atmosphere and the ocean the purposes of this paper are 1 to provide an economic foundation for environmental policies based on the precautionary principle and the 1992 rio declaration on environment and development and 2 to show that this optimal timing rule has a reservation property furthermore i analyze the effect of an increase in ambiguity on the optimal timing of adopting some environmental policy and show that an increase in ambiguity decreases the optimal timing of adopting the environmental policy

precautionary principle and robustness for a stock pollutant with multiplicative risk the interest shown by policy makers and economists in the precautionary principle indicates the importance of model uncertainty in global warming policy i show that through robust control policy makers can implement the precautionary principle to regulate a stock pollutant and i analyze its effect on expected steady state pollution taxes stocks and welfare the paper is broadly comprised of a theoretical part and an application to global warming policy i find that 1 an increase in either uncertainty about the model or risk about abatement cost increases expected steady state pollution taxes 2 a robust policy is preferred for any level of model uncertainty and this preference increases for either higher model uncertainty or higher multiplicative risk and 3 the effect on expected steady state pollution taxes and stock of introducing model uncertainty is relatively small for high levels of model uncertainty these results advocate using robust policies for a stock pollutant in the presence of model uncertainty

coupled economic ecological systems with slow and fast dynamics modelling and analysis method the purpose of this article is to contribute to the exploration of non convex dynamics in coupled human nature systems we study welfare issues associated with the management of a human nature complex adaptive system with a threshold and a stochastic driver we exemplify with a specific system where we link changes in the number and diversity of birds to the abundance of a pest insects that causes damages to goods and services valuable to human beings we present a method that simplifies the analysis and helps us discuss different management models that combine direct and indirect controls of the pest this allows us to show that 1 the choice of control method depends in a highly non linear way on biodiversity characteristics and 2 the socially optimal outcome may not be reachable using price instruments hence the price vs quantity debate needs to be revisited using a complex adaptive system lens

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

dynamic environmental policy with strategic firms prices versus quantities abstract environmental regulators often have imperfect information about regulated firms abatement costs in this paper we compare taxes and emissions permits in a dynamic setting in which firms behave strategically the regulator updates policy over time based upon previous aggregate industry performance assuming that firms are not strategic we find that strategic firms facing an emissions tax have an incentive to overabate in order to obtain a lower tax in the future firms that trade emissions permits have a strategic incentive to reveal an artificially high permit price to obtain more permits in the future whether permits or taxes are preferred from a welfare standpoint depends upon how permit prices are determined taxes generate higher welfare when the low cost firm sets the permit price but permits generate higher welfare when the high cost firm sets the permit price

a cost benefit analysis of slowing climate change there are many conflicting views regarding the true dimensions of the climate change problem often these viewpoints are based on different estimates of key parameters with little indication as to why parameter estimates vary so much and which ones might be the more reliable the prospects for a co ordinated strategy to tackle climate change appear dim little consensus has emerged for example regarding the costs of abating carbon emissions some take the view that considerable improvements in energy efficiency are available at negative cost by setting minimum efficiency standards for vehicles and domestic appliances e g mills et al 1991 others regard the macroeconomic costs of even small reductions in carbon emissions as substantial manne and richels 1993 in the judgement of other researchers a proportion of carbon emissions arise purely as a result of institutional failings either at a regional level in the subsidies paid to fossil fuel energy producers in the erroneous belief that this promotes economic growth shah and larsen 1994 in failure to deal with air pollution glomsrod et al 1992 and vehicle congestion in urban areas hughes 1994 or at a global level in failing to make appropriate transfers to those countries whose forests contain rich biodiversity which we would wish to preserve pearce 1991

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

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

regulation by prices quantities or both a review of instrument choice choosing appropriate policy instruments is an important part of successful regulation once objectives are agreed and suitable targets adopted policy makers can employ command and control regulation and or economic instruments and choose between fixing a price or a quantity this paper examines the relative advantages of price quantity and hybrid instruments according to their efficiency under uncertainty the trade off between credible commitment and flexibility implementation international considerations and political economy various illustrations of the theory are provided with two detailed applications to climate change and transport policy specifically congestion and safety pricing

managing partially protected resources under uncertainty it is common wisdom that open access leads to the inefficient use of resources and private ownership of resources improves efficiency however the impact of enclosure and efficient management of some resource pools on other open access resource pools is poorly recognized the problem is common to many congestion prone facilities including roads parks fisheries antibiotics grazing lands and wilderness areas in this paper we analyze the optimality of price and quantity instruments in regulating resource use when there is uncertainty about congestion costs price instruments are found to be preferable to quantity instruments and strictly so when demand is less than perfectly elastic we also explore the effect of market power by resource owners on the relative efficiency of the two instruments

when winners feel like losers evidence from an energy subsidy reform in 2011 the government of el salvador implemented a reform to the gas subsidy that increased the welfare of households in all but the top two deciles of the income distribution however the reform turned out to be rather unpopular especially among winners this paper relies on ad hoc household surveys conducted before the implementation and in the following two and a half years to test which factors help explain the puzzle the analysis uses probit and logit models to show that misinformation a negativity bias by which people with limited information inferred negative consequences mistrust of the government s ability to implement the policy and political priors explain most of the un satisfaction before implementation perceptions improved gradually and significantly so over time when the subsidy reception induced households to update their initial priors although political biases remained significant throughout the entire period the results suggest several implications with respect to policy reforms in cases where agents have limited information

regulation of stock externalities with correlated abatement costs we study a dynamic regulation model where firms actions contribute to a stock externality the regulator and firms have asymmetric information about serially correlated abatement costs with price based policies such as taxes or if firms trade quotas efficiently the regulator learns about the evolution of both the stock and costs this ability to learn about costs is important in determining the ranking of taxes and quotas and in determining the value of a feedback rather than an open loop policy for a range of parameter values commonly used in global warming studies taxes dominate quotas regardless of whether the regulator uses an open loop or a feedback policy and regardless of the extent of cost correlation

pollution control with uncertain stock dynamics when and how to be precautious abstract the precautionary principle pp applied to environmental policy stipulates that in the presence of uncertainty society must take robust preventive action to guard against worst case outcomes it follows that the higher the degree of uncertainty the more aggressive this preventive action should be this normative maxim is explored in the case of a stylized dynamic model of pollution control with uncertain in the knightian sense stock dynamics using the robust control framework of hansen and sargent 12 optimal investment in damage control is found to be increasing in the degree of uncertainty thus confirming the conventional pp wisdom optimal mitigation decisions however need not always comport with the pp in particular when damage control investment is both sufficiently cheap and sensitive to changes in uncertainty damage control investment and mitigation may act as substitutes and a pp with respect to the latter can be unambiguously irrational the theoretical results are applied to a calibrated linear quadratic model of climate change the analysis suggests that a reversal of the pp with respect to mitigation while theoretically possible is very unlikely

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

a 4 stated dice quantitatively addressing uncertainty effects in climate change we introduce a version of the dice 2007 model designed for uncertainty analysis dice is a wide spread deterministic integrated assessment model of climate change climate change long term economic development and their interactions are highly uncertain the quantitative analysis of optimal mitigation policy under uncertainty requires a recursive dynamic programming implementation of integrated assessment models such implementations are subject to the curse of dimensionality every increase in the dimension of the state space is paid for by a combination of exponentially increasing processor time lower quality of the value or policy function approximations and reductions of the uncertainty domain the paper promotes a state reduced recursive dynamic programming implementation of the dice 2007 model we achieve the reduction by simplifying the carbon cycle and the temperature delay equations we compare our model s performance and that of the dice model to the scientific aogcm models emulated by magicc 6 0 and find that our simplified model performs equally well as the original dice model our implementation solves the infinite planning horizon problem in an arbitrary time step the paper is the first to carefully analyze the quality of the value function approximation using two different types of basis functions and systematically varying the dimension of the basis we present the closed form continuous time approximation to the exogenous discretely and inductively defined processes in dice and we present a numerically more efficient re normalized bellman equation that in addition can disentangle risk attitude from the propensity to smooth consumption over time

tax versus trading and efficient revenue recycling as issues for greenhouse gas abatement abstract we give empirical welfare results for global greenhouse gas emission abatement using the first multi party model to include both tax versus trading under uncertainties and revenue recycling including multiple independent parties greatly reduces the welfare advantage of an emissions tax over emissions permit trading in handling abatement cost uncertainties from that shown by existing single party literature but a previously ignored and much bigger advantage of a tax from better handling uncertainties in business as usual emissions greatly boosts the overall tax versus trading advantage yet the degree to which each mechanism is used to raise and recycle revenue efficiently by lowering distortionary taxes rather than recycle revenue as lump sums or not raise revenue by giving tax thresholds or free permits may in turn dominate any tax versus trading advantage choosing the best greenhouse abatement mechanism should thus consider the issues of tax versus trading and efficient revenue recycling together

business cycles and emission trading with banking abstract we propose an emission cap adjustment policy for an emission trading system ets that allows banking of allowances for later use and faces business cycle uncertainty the forward looking banking decisions cause a commitment problem with respect to regulator s next period allowance supply decision we tackle the commitment problem by focusing on the markov equilibrium of the policy the equilibrium policy has a surprisingly simple structure combining features from both price and quantity instruments the regulator s ability to choose a new cap for each period does not render banking obsolete but on the contrary makes banking an integral part of the equilibrium policy using data from the eu ets to calibrate the model we solve the markov equilibrium policy for the case of carbon emissions regulation and compare markov policies with and without the possibility to bank allowances a counterfactual analysis of the eu ets during the period of 2009 2013 shows that the optimal markov policy would have led to a steadier allowance price level and a stricter emission regulation than what was actually observed in the eu ets

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

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

strategic climate policy with offsets and incomplete abatement carbon taxes versus cap and trade abstract this paper provides a first analysis of a policy bloc of fossil fuel importers which implements an optimal climate policy faces a non policy fringe of other fuel importers and an exporter bloc and purchases offset from the fringe we compare a carbon tax and a cap and trade scheme for the policy bloc in either case accompanied by an efficient offset mechanism for reducing emissions in the fringe the policy bloc is shown to prefer a tax over a cap since only a tax reduces the fuel export price and by more when the policy bloc is larger offsets are also more favorable to the policy bloc under a tax than under a cap the optimal offset price under a carbon tax is below the tax rate while under a cap and free quota trading the offset price must equal the quota price the domestic carbon and offset prices are both higher under a tax than under a cap when the policy bloc is small when the policy bloc is larger the offset price can be higher under a cap fringe countries gain by mitigation in the policy bloc more under a carbon tax since the fuel import price is lower

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

on environmental taxation under uncertain environmental damage this paper addresses optimal taxation when therelationship between the consumption of a dirty good and the resulting environmentaldamage is uncertain and treated as a randomvariable by policy makers the main purpose isto analyze how increased uncertainty measuredas a mean preserving increase in the spread ofthis random variable affects the optimalcommodity tax on the dirty consumption good incase the only task of government is to correctthe environmental externality and if thepreferences are characterized by nondecreasingabsolute risk aversion we find that thecommodity tax on the dirty consumption goodincreases in response to additionaluncertainty if on the other hand thegovernment provides a public good and uses alump sum tax in addition to the commodity tax it is possible that the commodity tax decreasesas a response to additional uncertainty evenif the preferences are characterized bynondecreasing absolute risk aversion a similarresult emerges although for different reasons if the lump sum tax is replaced by a laborincome tax

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

managing permit markets to stabilize prices the political economy of environmental policy favors the use of quantity based instruments over price based instruments e g tradable permits over green taxes at least in the united states with cost uncertainty however there are clear efficiency advantages to prices in cases where the marginal damages of emissions are relatively flat such as with greenhouse gases the question arises therefore of whether one can design flexible quantity policies that mimic the behavior of price policies namely stable permit prices and abatement costs we explore a number of quantity plus policies that replicate the behavior of a price policy through rules that adjust the effective permit cap for unexpectedly low or high costs they do so without necessitating any monetary exchanges between the government and the regulated firms which can be a significant political barrier to the use of price instruments

liquidity a new monetarist perspective this essay surveys the new monetarist approach to liquidity work in this literature strives for empirical and policy relevance plus rigorous foundations questions include what is liquidity is money essential in achieving desirable outcomes which objects can or should serve in this capacity when can asset prices differ from fundamentals what are the functions of commitment and collateral in credit markets how does money interact with credit and intermediation what can and should monetary policy do the research summarized emphasizes the micro structure of frictional transactions and studies how institutions like monetary exchange credit arrangements or intermediation facilitate the exchange process

the damage costs of climate change toward more comprehensive calculations it is argued that estimating the damage costs of a certain benchmark climate change is not sufficient what is needed are cost functions and confidence intervals although these are contained in the integrated models and their technical manuals this paper brings them into the open in order to stimulate discussion after briefly reviewing the benchmark climate change damage costs region specific cost functions are presented which distinguish tangible from intangible losses and the losses due to a changing climate from those due to a changed climate furthermore cost functions are assumed to be quadratic as an approximation of the unknown but presumably convex functions results from the damage module of the integrated climate economy model fund are presented next uncertainties are incorporated and expected damages are calculated it is shown that because of convex loss functions and right skewed uncertain ties the risk premium is substantial calling for more action than analysis based on best guess estimates the final section explores some needs for further scientific research

optimal climate change mitigation under long term growth uncertainty stochastic integrated assessment and analytic findings abstract economic growth over the coming centuries is one of the major determinants of today s optimal greenhouse gas mitigation policy at the same time long run economic growth is highly uncertain this paper is the first to evaluate optimal mitigation policy under long term growth uncertainty in a stochastic integrated assessment model of climate change the sign and magnitude of the impact depend on preference characteristics and on how damages scale with production we explain the different mechanisms driving optimal mitigation under certain growth under uncertain technological progress in the discounted expected utility model and under uncertain technological progress in a more comprehensive asset pricing model based on epstein zin weil preferences in the latter framework the dominating uncertainty impact has the opposite sign of a deterministic growth impact the sign switch results from an endogenous pessimism weighting all of our numeric scenarios use a dice based assessment model and find a higher optimal carbon tax than the deterministic dice base case calibration

the role of stocks and shocks concepts in the debate over price versus quantity recent literature showed that the choice between a price or quantity control depends in part on the dynamic structure of cost uncertainty temporary shocks to abatement cost favors the use of a price control while permanent shocks favor a quantity control unfortunately the importance of this assumption to the optimal choice has not yet received wide attention among economists we analyze the regulatory sproblem in an alternative setting and reproduce these results our contribution is the simplicity of the model and the accessibility of the results which reinforce the critical role played by the assumed structure of uncertainty

prices vs quantities technology choice uncertainty and welfare technological improvements have proven essential in mitigating environmental problems such as climate change depletion of the ozone layer and acid rain while it is well known that price and quantity based regulatory instruments provide different investment levels the effects on the choice between different technologies have received scant attention this paper expands on the prices versus quantities literature by investigating firms technology choice in the face of demand and supply side uncertainty i show that the regulator can not design tradable emissions permits and an emissions tax such that the two regimes are equivalent even in terms of expected values moreover a tax encourages the most flexible abatement technology if and only if stochastic costs and the equilibrium permit price have sufficiently strong positive covariance compared with the variance in consumer demand for the good produced finally the firms technology choices are socially optimal under tradable emissions permits but not under an emissions tax