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

planning under incomplete information and the ratchet effect abstract central planning of production is usually performed under asymmetric information the firm in general has more information about its productive possibilities than the central planner from now on for short cp this justifies the use of incentives schemes in which the cp does not directly fix activity levels casual observation of such existing schemes suggests that the time dimensions is crucial for their working typically the cp revises the incentive scheme over time to take into account the information provided by the firm s performance managers of centrally planned economies as well as economists have long recognized that this revision induces firms to underproduce in order to avoid demanding schemes in the future this is the ratchet effect it is purpose of the present paper to study the ratchet effect under the non commitment assumption which we believe to be more realistic the inadequacy of conceptual tools made if difficult in the past to consider such an assumption now basic research on dynamic games with incomplete information recently resulted in new ideas which look particularly relevant for a theoretical analysis of the problem

a derivation of the marginal abatement cost curve abstract the relationship between a firm s technology and its marginal abatement cost mac curve is explored even under the simplest specifications the mac curve will be kinked at some point except under a special assumption which in reality could easily be violated the nondifferentiability implies that the choice of instrument under uncertainty may depend on the targeted level of emissions reduction also stability conditions for dynamic tax mechanisms may be violated in the neighborhood of the kink point a policy implication is that in some cases output restrictions are as efficient as emissions restrictions in contrast to previous results

what are the key drivers of mac curves a partial equilibrium modelling approach for the uk marginal abatement cost mac curves are widely used for the assessment of costs related to co2 emissions reduction in environmental economics as well as domestic and international climate policy several meta analyses and model comparisons have previously been performed that aim to identify the causes for the wide range of mac curves most of these concentrate on general equilibrium models with a focus on aspects such as specific model type and technology learning while other important aspects remain almost unconsidered including the availability of abatement technologies and level of discount rates this paper addresses the influence of several key parameters on mac curves for the united kingdom and the year 2030 a technology rich energy system model uk markal is used to derive the mac curves the results of this study show that mac curves are robust even to extreme fossil fuel price changes while uncertainty around the choice of the discount rate the availability of key abatement technologies and the demand level were singled out as the most important influencing factors by using a different model type and studying a wider range of influencing factors this paper contributes to the debate on the sensitivity of mac curves

firm incentives to promote technological change in pollution control reply abstract the process of technological change in pollution control is broken into three basic steps innovation diffusion and optimal agency response firm incentives to promote these steps are then examined under five regulatory regimes direct controls emission subsidies emission taxes free marketable permits and auctioned marketable permits on a relative basis emission taxes and auctioned permits provide the highest firm incentives to promote technological change at times free permits generate lower incentives direct controls which are common regulatory tools usually provide the lowest relative firm incentives to promote technological change

the hotspots reference routes and research trends of marginal abatement costs a systematic review abstract as one of the most effective means of evaluating environmental policies marginal abatement costs macs have been adopted in a growing body of research this study characterizes the mac related literature from 1993 to 2018 on web of science based on a systematic review bibliometric analysis and mind mapping the results classify the research hotspots into influential factors methods and empirical applications the three most frequently mentioned influential factors are technical change discount rates and energy prices compared with top down models bottom up models including engineering model and expert based method are the most widely used improvements in the former focus on strengthening market behavior effect while those in the latter aim to overcome the weaknesses of negative costs and lack of interaction across measures mac applications focus on environmental policies with two new research areas recently emerging co benefits and sectoral abatement costs furthermore a reference route is proposed by summarizing the applicability of methods and matching relationships among influential factors methods and empirical problems finally potential research directions are summarized based on the identified research hotspots and a similar co word analysis in marginal cost field such as considering the effects of both multiple influential factors and the interaction among factors on maccs

environmental policy incentives to adopt advanced abatement technology abstract we investigate incentives through environmental policy instruments to adopt advanced abatement technology first we study the case where the regulator makes long term commitments to policy levels and does not anticipate arrival of new technology we show that taxes provide stronger incentives than permits auctioned and free permits offer identical incentives and standards may give stronger incentives than permits second we investigate scenarios where the regulator anticipates new technologies we show that with taxes and permits the regulator can induce first best outcomes if he moves after firms have invested whereas this does not always hold if he moves first

instrument choice for environmental protection when technological innovation is endogenous this paper compares qualitatively and quantitatively the welfare effects of emissions taxes auctioned emissions permits and free grandfathered permits when technological innovation is endogenous we find that there is no unambiguous case for preferring any of these policy instruments the relative welfare ranking of instruments depends on the costs of innovation the extent to which innovations can be imitated the slope and level of the marginal environmental benefit function and the number of polluting firms we illustrate the types of situations when there can be significant welfare discrepancies between the policies and when there are not

a nonparametric method to estimate a technical change effect on marginal abatement costs of u s coal power plants the literature usually assumes that technical change reduces marginal abatement cost however recent results suggest that precisely the opposite occurs this paper proposes a nonparametric method to determine the effect of technical change on marginal abatement cost the method decomposes nox marginal abatement cost changes in 2000 2004 and in 2004 2008 for 325 boilers operating in 134 u s bituminous coal power plant into technical and non technical change effects we find that technical change reduces the nox marginal cost about 28 3 in 2000 2004 and 26 5 in 2004 2008 however more stringent regulations enacted the nox budget program results in lower nox emission levels as plant operators install more advanced nox abatement equipment which in turn causes an overall increase in marginal abatement cost

comparative statics of the optimal dynamic incentive contract abstract each period a firm must carry out an indivisible project the cost of which depends on the firm s constant efficiency and its variable level of effort only the cost is observed by the regulator who has to choose the incentive scheme the optimal dynamic mechanism is derived under possible commitment of the regulator over time then under non commitment it is shown that there are four types of continuation equilibria also the profile of effort levels is compared to the commitment case finally some numerical comparative statics is performed and it is shown that all types of equilibria can be optimal

the ratchet effect and the coordination of production in the absence of rent extraction valuable to offset the cost these net gains may help explain why the ratchet has been observed in situations as diverse as managerial reward systems in the soviet union and salesman bonus arrangements in capitalist countries

spatial approach to sustainable development challenges of equity and efficacy zuindeau b 2006 spatial approach to sustainable development challenges of equity and efficacy regional studies 40 459 470 examining sustainable development by favouring a spatial approach leads one to modify the definition of the challenges relating to this issue the present paper considers the two challenges of equity and efficacy and it tries to specify the variables that influence each of them in a spatial approach in order to do this it draws on the existing literature highlighting the differences in treatment depending on the approach and also stressing the weaknesses overall it is believed that the spatial dimension exacerbates the contradictions that arise from the implementation of sustainable development in particular the contradictions that are likely to appear between a logic of sustainability and a logic of competitiveness the paper concludes by examining the question of governance zuindeau b 2006 approche spatiale du developpement durable enjeux d equite et d efficacite

does technological innovation really reduce marginal abatement costs some theory algebraic evidence and policy implications the existing literature models innovation in pollution control as a reduction in marginal abatement costs we show that this assumption is inappropriate for production process innovations such as fuel switching algebraically we examine the effects of different innovation types on marginal abatement cost curves showing that some desirable innovations increase marginal abatement costs empirically we estimate marginal abatement costs for sulfur dioxide by measuring the output distance function for electric power in korea regression results confirm that production process innovations did raise marginal abatement costs in this case one policy implication economic instruments do not always provide stronger innovation incentives than command and control policies

representing induced technological change in models for climate policy analysis induced technological change itc whereby the relative price effects of reducing greenhouse gas emissions stimulate innovation that mitigates the cost of abatement is both tantalizing to decision makers and challenging to represent in the computational economic and engineering models used to analyze climate change policy this overview reconciles the divergent views of technology and technological change within different types of models elucidates the theoretical underpinnings of itc introduces the reader to the techniques of their practical implementation and evaluates the implications for models results

technical change and the marginal cost of abatement abstract we address one aspect of the treatment of technical change in the environmental economics literature how technical change impacts the marginal cost of abatement we review a selection of papers that employ a variety of representations of technical change and show that these representations have quite different and sometimes surprising effects on the marginal costs of pollution reductions we argue that these varied representations in fact correspond to a variety of different technology options we then present results indicating that this representation matters the impacts of technical change on the marginal cost of abatement can crucially impact policy analysis

incentives to diffuse advanced abatement technology under environmental liability law polluting firms with advanced abatement technology at their disposal have incentives or disincentives to share this technology with other polluting firms the direction and extent of those incentives depends on the liability rule applicable and the way technical change impacts marginal abatement costs we establish that incentives for diffusion are socially optimal under strict liability and socially suboptimal under negligence if technical change lowers marginal abatement costs for all levels of abatement negligence may however induce better diffusion incentives than strict liability if technical change decreases increases marginal abatement costs for low high levels of abatement

monopoly with incomplete information recent theoretical research on principal agent relationships has emphasized incentive problems that arise when the parties involved are constrained by either asymmetric information or their inability to monitor each other s actions here we concentrate on the former constraint and consider the case of a single principal the monopolist the main contribution is to show that under a separability assumption strong conclusions can be drawn about the nature of optimal incentive schemes although the primary focus is on optimal quantity discounts in a monopolized market the results also shed light on related topics such as optimal income taxation and commodity bundling

the third sector and the regional development of social capital birch k and whittam g the third sector and the regional development of social capital regional studies there is a growing academic and policy interest in the third sector and its potential impact on regional development a key aspect of the third sector is its role in regional development through the promotion of social capital however there is considerable debate around the definition of the third sector that limits one s understanding of its impact the paper first disentangles a number of ambiguities to clarify the distinctions between the concepts before then exploring the relationship between the regional development of social capital and the various aspects of the third sector finally uk policy agendas and initiatives are considered in light of the earlier discussion birch k et whittam g le secteur tertiaire et le developpement regional du capital social regional studies le monde universitaire et la politique s interessent de plus en plus au secteur tertiaire et a son impact potentiel s

does more stringent environmental regulation induce or reduce technology adoption when the rate of technology adoption is inverted u shaped abstract we show that for a broad class of technologies the relationship between policy stringency and the rate of technology adoption is inverted u shaped this happens when the marginal abatement cost mac curves of conventional and new technologies intersect which invariably occurs when emissions are proportional to output and technological progress reduces emissions per output this outcome does not result from policy failure on the contrary in social optimum the relationship between the slope of the marginal damage curve and the rate of technology adoption is also inverted u shaped under more general conditions these curves can look even more complicated e g such as inverted w shaped

rediscovering place and accounting space how to re embed the human economy abstract this article proposes to move beyond monetary assessments of ecosystem services in order to counteract an important mechanism behind their current undervaluation the process of disembedding disembedding describes the influence of modernity on social relationships it also clarifies how human nature relationships have been affected modern societies have become disembedded from the context of local ecosystems resulting in diminishing knowledge of and attention to ecosystem services the emergence of general purpose money is presented as a key factor in the disembedding process because it has brought with it the message of substitutability and the possibility of an increasing appropriation of distant ecosystems the paper argues that in order to re embed societies instead of pursuing current trends the limits to human expansion in the biosphere have to be made visible therefore a strategy of re embedding the human economy into the life support context is put forward where bioregional thought and its intention of rediscovering mapping and re inhabiting local places is combined with the ecological footprint tool in contrast to monetary assessments of ecosystem services the ecological footprint assessment presents the limits of the services availability and thus clarifies the fact that increased appropriation of bio productive space normally involves increasing pressure on remaining ecosystems

the dynamics of incentive contracts the paper studies a simple two period principal agent model in which the principal updates the incentive scheme after observing the agent s first period performance the agent has superior information about his ability the principal offers a first period incentive scheme and observes some measure of the agent s first period performance cost or profit which depends on the agent s ability and unobservable first period effort the relationship is entirely run by short term contracts in the second period the principal updates the incentive scheme and the agent is free to accept the new incentive scheme or to quit the strategies are required to be perfect and updating of the principal s beliefs about the agent s ability follows bayes rule the central theme of the paper is that the ratchet effect leads to much pooling in the first period first for any first period incentive scheme there exists no separating equilibrium second when the uncertainty about the agent s ability is small the optimal scheme must involve a large amount of pooling the paper also gives necessary and sufficient conditions for the existence of partition equilibria and looks at the effect of cost uncertainty

on the sources of technological change assessing the evidence this paper uses a selective review of the economic literature on technological change to support four points that are important for interpreting and incorporating technological change into formal models of energy and the environment the review 1 supports the notion that no single source dominates the process of technological change it supports roles for rd 3 indicates that these spillovers are often indirect requiring own industry activities to utilize and 4 indicates that simple experience curve calibrations often used in formal models likely include a range of sources of technological change in addition to learning by doing some of which might not be induced by the sorts of policies typically considered in the climate context

allocation of pollution abatement under learning by doing abstract this paper examines how learning by doing affects the allocation of pollution abatement between heterogeneous technologies over time the optimal policy balances current abatement costs against reductions in future costs and infant technologies may be preferred to mature technologies despite greater initial costs we characterize when a technological winner might emerge and we identify conditions under which optimal abatement is shared across all technologies pigouvian taxes can implement the first best but may need to be differentiated across technologies when technical change is induced an important role of environmental policies is to put abatement on the right technological trajectories

marginal abatement costs of greenhouse gas emissions a meta analysis in this paper we carry out a meta analysis of recent studies into the costs of greenhouse gas mitigation policies that aim at the long term stabilisation of these gases in the atmosphere we find the cost estimates of the studies to be sensitive to the stringency of the stabilisation target the assumed emissions baseline the way in which the time profile of emissions is determined in the model the choice of control variable co2 only versus multigas the number of regions and energy sources in the model and to a lesser degree the scientific forum in which the study was developed we find that marginal abatement costs of the stringent long term targets that are currently considered by the european commission are still very uncertain but might exceed the costs that have been suggested by recent policy assessments

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

be realistic demand the impossible moving towards strong sustainable development in an old industrial region the term sustainable development provides useful guidance on how economic development can be reconciled with protecting the natural environment and meeting social objectives however this rather tricky term is open to a number of interpretations ranging from strong ecological to weak technocratic in the context of an old industrial region evidence of movement towards strong sustainable development in four areas is discussed radicalising democracy promoting the local social economy meeting basic needs and encouraging biodiversity the article explores why in the light of sustained evidence of multiple social and environmental crises these messages of strong ecological sustainable development continue to be ignored and marginalized in formulating policy at the regional level

a paler shade of green environmental policy under induced technical change conventional wisdom argues that environmental policy is less costly if it induces the development of cleaner technologies in contrast to this argument we show that once the second best nature of actual economies is taken into account the cost of environmental policy may well be larger with induced technical change itc than without thus itc may lower both the emissions reductions and the welfare gains associated with environmental policy in an endogenous policy framework itc may reduce the desired stringency of the policy

using cost observation to regulate firms the paper emphasizes the use of accounting data in regulatory or procurement contracts when the supplier 1 has superior information about the cost of the project and 2 invests in cost reduction the main result states that under risk neutrality the supplier announces an expected cost and is given an incentive contract linear in cost overruns this optimal contract moves toward a fixed price contract as the announced cost decreases an investment choice is then introduced and the use of a rate of return regulation is studied

a complete solution to a class of principal agent problems with an application to the control of a self managed firm this paper considers a class of principal agent problems which have the following features 1 there is adverse selection because the principal ignores the value of one parameter of the agent s true characteristics 2 leaving aside the information parameter the principal s welfare as well as the agent s welfare depend on two types of variables observable to both of them the first ones possibly multidimensional are called action variable s and the second one which is one dimensional has in general the meaning of a money transfer 3 the principal is a stackelberg leader of the two person game he can commit himself to decision rules which are admissible on informational grounds he optimizes within the adequate class taking into account besides the agent s reaction one constraint which has generally the meaning of an individual rationality constraint and sometimes of a feasibility constraint the optimization is limited to the class of non stochastic mechanisms 4 the problem can also receive an alternative interpretation the principal faces a continuum of agents of unknown characteristics the distribution being known however stylized principal agent problems of this type have often been considered in the economic literature in particular the reader will later be able to recognize that the standard income tax model a la mirrlees 1971 the quality or quantity choice model of the monopolist a la mussa and rosen 1978 or maskin and riley 1982 and the model of government regulation of the private monopolist of baron and myerson 1982 all belong to

the target incentive system vs the price incentive system under adverse selection and the ratchet effect abstract in a dynamic adverse selection type of principal agent relationship where the principal is committed over time to a particular incentive system with fixed structure but variable parameters but not to any intertemporal incentive scheme with both fixed structure and parameters the ratchet effect arises but varies with different incentive systems we show that compared with using prices as the sole planning mode the principal can attenuate the ratchet effect by stipulating targets as well as a result the target incentive system entails higher expected welfare than the price incentive system in a perfect bayesian equilibrium

incentives for advanced pollution abatement technology at the industry level an evaluation of policy alternatives abstract in this research we evaluate the incentive effects of five environmental policy instruments to promote the development and adoption of advanced pollution abatement technology in a heterogenous industry from most to least incentive the policy instruments can be rank ordered as follows i auctioned permits ii emissions taxes and subsidies iii issued marketable permits iv performance standards including performance standards in this list necessitates the assumption that they are differentiated between heterogeneous firms before the technology adoption in a way which replicates the initial emissions control distribution of the efficient incentive based instruments with the starting point normalized in this fashion the instrument rankings are invariant with respect to the size of firms the size of the industry or the industry s abatement cost structure

markets and regulatory hold up problems abstract many regulatory programs such as environmental regulation are effective only if firms make irreversible investments that reduce the cost of compliance a firm potentially subject to regulation may therefore behave strategically by not investing thereby forcing the regulator to void the proposed regulation we show that such incentives which resemble a hold up problem may not be overcome when government s only tool is the imposition of an emissions tax the hold up problem can be overcome by the issuance of tradeable permits a time consistent equilibrium exists with all firms investing and the government imposing regulations even if no permits are traded and their market price is low indeed an observation of no trade may indicate that pollution abatement is great

innovation in pollution control comparisons of the various institutional arrangements for controlling pollutant emissions from individual sources effluent fees effluent control subsidies marketable permits and direct command and control regulation have usually focused on their static efficiency properties and institutional feasibility e g dales 1968 zerbe 1970 baumol and oates 1975 kneese and schultze 1975 marin 1978 mills and white 1978 spence and weitzman 1978 russell 1979 a relatively neglected area has been the study of how each arrangement influences innovation in pollution control a few studies e g kneese and schultze 1975 marin 1978 mills and white 1978 russell 1979 have casually claimed that the control methods that rely on economic incentives provide superior incentives for innovation but there have been few systematic studies of the question this paper provides a simple model of pollution control innovation by a profitmaximizing polluter who is subject to the various control methods the consequences of the methods will be explored in three major contexts first we assume that the polluter and the innovation is a small enough part of the overall pollution problem so that none of the important marginal conditions are changed by the innovation second we assume that the polluter and the innovation are important enough so that marginal conditions are changed by the innovations but that the governmental authority determining pollution control incentives or levels fails to make the appropriate adjustments third we again assume that the innovation causes marginal conditions to change but in this case the governmental authority makes the appropriate adjustments we use the term ratcheting to describe this last phenomenon in all cases we assume that the innovating polluter correctly predicts the reactions of the governmental authority and bases his innovation decisions on that prediction a profit maximizing entrepreneur would normally be expected to adopt any innovation that promised gains present discounted value to him in excess of initial

policy interactions risk and price formation in carbon markets carbon pricing is an important mechanism for providing companies with incentives to invest in carbon abatement price formation in carbon markets involves a complex interplay between policy targets dynamic technology costs and market rules carbon pricing may under deliver investment due to r d externalities requiring additional policies which themselves affect market prices also abatement costs depend on the extent of technology deployment due to learning by doing this paper introduces an analytical framework based on marginal abatement cost mac curves with the aim of providing an intuitive understanding of the key dynamics and risk factors in carbon markets the framework extends the usual static mac representation of the market to incorporate policy interactions and some technology cost dynamics the analysis indicates that supporting large scale deployment of mature abatement technologies suppresses the marginal cost of abatement sometimes to zero whilst increasing total abatement costs however support for early stage r d may reduce both total abatement cost and carbon price risk an important aspect of the analysis is in elevating risk management considerations into energy policy formation as the results of the stochastic modelling indicate wide distributions for the emergence of carbon prices and public costs around the policy expectations

aggregation and linearity in the provision of intertemporal incentives we consider the problem of providing incentives over time for an agent with constant absolute risk aversion the optimal compensation scheme is found to be a linear function of a vector of n accounts which count the number of times that each of the n kinds of observable events occurs the number n is independent of the number of time periods so the accounts may entail substantial aggregation in a continuous time version of the problem the agent controls the drift rate of a vector of accounts that is subject to frequent small random fluctuations the solution is as if the problem were the static one in which the agent controls only the mean of a multivariate normal distribution and the principal is constrained to use a linear compensation rule if the principal can observe only coarser linear aggregates such as revenues costs or profits the optimal compensation scheme is then a linear function of those aggregates the combination of exponential utility normal distributions and linear compensation schemes makes computations and comparative statics easy to do as we illustrate we interpret our linearity results as deriving in part from the richness of the agent s strategy space which makes it possible for the agent to undermine and exploit complicated nonlinear functions of the accounting aggregates

participation games and international environmental agreements a non parametric model abstract we examine the size of stable coalitions in a participation game that has been used to model international environmental agreements cartel formation rd based on these examples a consensus has emerged that in this kind of game the equilibrium coalition size is small except possibly when the potential benefits of cooperation are also small in this paper we develop a non parametric approach to the problem and demonstrate that the conventional wisdom is not robust in a general setting we identify conditions under which the equilibrium coalition size can be large even when potential gains are large contrary to previously examined leading special cases we show that reductions in marginal abatement costs in an international environmental game can increase equilibrium membership and we provide a measure of the smallest reduction in costs needed to support a coalition of arbitrary size

tax subsidy policies in the presence of environmentally aware consumers abstract we study policy measures to improve environmental quality in the presence of environmentally aware consumers we consider two sets of policy instruments uniform policies for the firms and policies that discriminate between the firms based on their environmental quality for the latter set either the better performer is rewarded with a subsidy or the worse performer is punished with a tax we find that while a uniform subsidy policy improves average environmental quality a uniform tax policy worsens it further while a discriminatory subsidy policy reduces total pollution and enhances aggregate welfare a discriminatory tax policy may increase total pollution and may reduce aggregate welfare

a tale of two market failures technology and environmental policy abstract market failures associated with environmental pollution interact with market failures associated with the innovation and diffusion of new technologies these combined market failures provide a strong rationale for a portfolio of public policies that foster emissions reduction as well as the development and adoption of environmentally beneficial technology both theory and empirical evidence suggest that the rate and direction of technological advance is influenced by market and regulatory incentives and can be cost effectively harnessed through the use of economic incentive based policy in the presence of weak or nonexistent environmental policies investments in the development and diffusion of new environmentally beneficial technologies are very likely to be less than would be socially desirable positive knowledge and adoption spillovers and information problems can further weaken innovation incentives while environmental technology policy is fraught with difficulties a long term view suggests a strategy of experimenting with policy approaches and systematically evaluating their success

regulating a monopolist with unknown costs we consider the problem of how to regulate a monopolistic firm whose costs are unknown to the regulator the regulator s objective is to maximize a linear social welfare function of the consumers surplus and the firm s profit in the optimal regulatory policy prices and subsidies are designed as functions of the firm s cost report so that expected social welfare is maximized subject to the constraints that the firm has nonnegative profit and has no incentive to misrepresent its costs we explicitly derive the optimal policy and analyze its properties in their classic papers dupuit 2 and hotelling 5 considered pricing policies for a bridge that had a fixed cost of construction and zero marginal cost they demonstrated that the pricing policy that maximizes consumer well being is to set price equal to marginal cost and to provide a subsidy to the supplier equal to the fixed cost so that a firm would be willing to provide the bridge this first best solution is based on a number of informational assumptions first the demand function is assumed to be known to both the regulator and to the firm while the assumption of complete information may be too strong the assumption that information about demand is as available to the regulator as it is to the firm does not seem unnatural a second informational assumption is that the regulator has complete information about the cost of the firm or at least has the same information about cost as does the firm this assumption is unlikely to be met in reality since the firm would be expected to have better information about costs than would the regulator as weitzman has stated an essential feature of the regulatory environment i am trying to describe is uncertainty about the exact specification of each firm s cost function in most cases even the managers and engineers most closely associated with production will be unable to precisely specify beforehand the cheapest way to generate various hypothetical output levels because they are yet removed from the production process the regulators are likely to be vaguer still about a firm s cost function 12 p 684 as this observation suggests it is natural to expect that a firm would have better information regarding its costs than would a regulator the purpose of this paper is to develop an optimal regulatory policy for the case in which the regulator does not know the costs of the firm one strategy that a regulator could use in the absence of full information about costs is to give the firm the title to the total social surplus and to delegate the pricing decision to the firm in pursuing its own interests which would then be to maximize the total social surplus the firm would adopt the same marginal cost pricing strategy that the regulator would have imposed if the regulator had

dynamic income taxation redistribution and the ratchet effect abstract in this paper we extend the classic optimum linear income tax model to a twice repeated game a utilitarian policy maker decides on the second period tax system on the basis of observed first period behaviour we summarise our findings as follows first the static optimal linear tax results cannot be expected to hold in a dynamic setting second more productive households are likely to mimic the behaviour of less productive households third the optimal dynamic first period tax rate might be negative then income is redistributed from low to high income households fourth if the utility function is well behaved then the optimal dynamic first period tax rate is lower than the optimal static tax rate fifth if the optimal static tax rate separates then the dynamic and the static optimal tax rates coincide sixth if a zero tax rate separates then the optimal dynamic tax rate is positive

pollution accumulation and firm incentives to accelerate technological change under uncertain private benefits the paper explores the relationships between the design of public incentives and the policy maker s desired timing of abandonment of a polluting technology when this requires an irreversible private investment and the firm faces uncertain appropriable benefits from the technological change two regulatory approaches are examined firstly we consider the quite common one of lowering the private investment cost through a subsidy in order to bridge the gap between the private and the policy maker s desired timing of environmental innovation secondly we consider a policy scenario where the regulator instead of simply lowering the investment s rental price also stimulates abandonment of the polluting technology by reducing through appropriate announcements the uncertainty surrounding the technological switch s private profitability we then compare the two approaches and show the latter s benefits in terms of the policy s effectiveness and or budgetary savings

endogenous technological change in climate change modelling this article investigates the impact on optimal co2 abatement and carbon tax levels of introducing endogenous technological change in a macroeconomic model of climate change we analyse technological change as a function of cumulative capacity as incorporated recently in energy systems models our calculations confirm that including endogenous innovation implies earlier emission reduction to meet atmospheric carbon concentration constraints however the effect is stronger than suggested in the literature moreover the development of non fossil energy technologies constitutes the most important opportunity for emission reductions optimal carbon tax levels reducing fossil energy use are lower than usually advocated