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

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

global warming irreversibility and learning a number of economists have argued that the literature on the irreversibility effect implies that current abatement of greenhouse gas emissions should be greater when there is the possibility of obtaining better information in the future about the potential damages from global warming than when there is no possibility of obtaining better information in this paper we show that even the simplest model of global warming does not satisfy either of epstein s 1980 sufficient conditions so it is not possible to use epstein s analysis to tell whether the irreversibility effect applies to models of global warming we derive an alternative sufficient condition for the irreversibility effect to hold

the induced innovation hypothesis and energy saving technological change we develop a methodology for testing hicks s induced innovation hypothesis by estimating a product characteristics model of energy using consumer durables augmenting the hypothesis to allow for the ine uence of government regulations for the products we explored the evidence suggests that i the rate of overall innovation was independent of energy prices and regulations ii the direction of innovation was responsive to energy price changes for some products but not for others iii energy price changes induced changes in the subset of technically feasible models that were offered for sale iv this responsiveness increased substantially during the period after energy efficiency product labeling was required and v nonetheless a sizable portion of efficiency improvements were autonomous

immigration and prices this paper examines the behavior of prices following the unexpected arrival of a large number of immigrants from the former soviet union fsu to israel during 1990 i use store level price data on 915 consumer price index products to show that the increase in aggregate demand prompted by the arrival of the fsu immigration significantly reduced prices during 1990 when one controls for native population size and city and month effects a one percentage point increase in the ratio of immigrants to natives in a city decreases prices by 0 5 percentage point on average it is argued that this negative immigration effect is consistent with fsu immigrants the new consumers having higher price elasticities and lower search costs than the native population thus immigration can have a moderating effect on inflation through its direct effect on product markets and not only by increasing the supply of labor

uncertain r d backstop technology and ghgs stabilization abstract this paper analyses optimal investments in innovation when dealing with a stringent climate target and with the uncertain effectiveness of r d the innovation needed to achieve the deep cut in emissions is modeled by a backstop carbon free technology whose cost depends on r d investments to better represent the process of technological progress we assume that r d effectiveness is uncertain by means of a simple analytical model we show how accounting for the uncertainty that characterizes technological advancement yields higher investments in innovation and lower policy costs we then confirm the results via a numerical analysis performed with a stochastic version of witch an energy economy climate model the results stress the importance of a correct specification of the technological change process in economy climate models

the optimal research and development portfolio of low carbon energy technologies a study of china to support decision making for an optimal portfolio strategy for low carbon energy technology research and development r d this study proposes a dynamic two stage stochastic programming model taking into account both the uncertainty of technological change and damages of climate change based on china s economic and technology level and expert elicitation an r d investment portfolio strategy looking at three low carbon technologies carbon capture and storage ccs solar photovoltaic pv and nuclear including nine projects is investigated through the proposed model the optimized results show that the optimal r d technology portfolio is robust to different levels of risk in climate damage however the total social costs for the optimal r d technology portfolio is lowest in the medium risk of climate damage scenario under different opportunity costs the composition of the optimal r d portfolio varies however projects for each of the three technologies always constitute the optimal r d portfolio furthermore the implication is that a technology synergistic r d strategy is conducive to enhancing the level of co2 abatement and reducing the total social cost

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

climate change and optimal energy technology r d policy public policy response to global climate change presents a classic problem of decision making under uncertainty theoretical work has shown that explicitly accounting for uncertainty and learning in climate change can have a large impact on optimal policy especially technology policy however theory also shows that the specific impacts of uncertainty are ambiguous in this paper we provide a framework that combines economics and decision analysis to implement probabilistic data on energy technology research and development r d policy in response to global climate change we find that given a budget constraint the composition of the optimal r d portfolio is highly diversified and robust to risk in climate damages the overall optimal investment into technical change however does depend in a non monotonic way on the risk in climate damages finally we show that in order to properly value r d abatement must be included as a recourse decision

immigration and international prices an initial assessment abstract using prices from a number of cities across the world during 1990 2006 this paper shows that there exists a negative impact of immigration on prices the estimated absolute elasticity of prices with respect to immigration is around 14 across specifications

technological change and uncertainty in environmental economics abstract technological change is widely believed to play a crucial role in mastering the challenges of man made climate change the drivers and impacts of technological change have therefore become an important research issue in the field of climate economics while models to analyze the interactions between economy energy and the environment initially treated technological change as exogenous more recent modeling approaches often represent technological change as endogenously induced typically models of induced technological change in climate economics are based on perfect foresight in a deterministic world however both technological change and climate impacts are subject to large uncertainties that may substantially affect the design of efficient climate policies against this background the special issue presents five articles contributing to the study of uncertainty and technological change in climate change economics

market reaction to the thrift bailout abstract this paper examines the share price reaction of depository institutions to the financial institutions reform recovery and enforcement act firrea passed august 1989 we find a favorable share price response for thrifts which could be attributed to enhanced depositor confidence reduced risk premiums on deposits reduced agency costs or reduced loan losses among other reasons however the effects of firrea on commercial banks were negligible an intra industry analysis revealed that the variation in share price responses could not be explained by cross sectional differences in thrift capital levels

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

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

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

r d and abatement under environmental liability law comparing incentives under strict liability and negligence if compensation differs from harm abstract this paper analyzes equilibrium r d in pollution control and equilibrium pollution abatement by polluters who are subject to environmental liability law when the level of compensation differs from the level of environmental harm we contrast the performance of strict liability with that of the negligence rule privately optimal levels necessarily deviate from socially optimal ones under strict liability whereas private decisions are first best under negligence unless compensation is much smaller than harm it is established that the way in which privately optimal r d deviates from the first best level depends on the kind of technical change in pollution abatement counterintuitively polluters might overinvest into r d in pollution control if compensation falls short of harm and may underinvest if compensation exceeds harm

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

technologies energy systems and the timing of co2 emissions abatement an overview of economic issues abstract this paper provides an overview of economic issues involved in timing limitations on co2 emissions from energy systems it highlights issues relating to technology availability development and diffusion and the inertia of energy systems as being particularly important the paper sets this in the context of wider uncertainties surrounding the problem and briefly considers other aspects relevant to timing the paper is stimulated by the debate in the usa about optimal abatement paths in particular recent claims that it would be economically preferable to defer such abatement action in favour of measures that support technology development but do not affect emission trends for many years this paper categorizes the various economic issues involved and concludes that for each economic argument that has been advanced to justify deferring emission constraints there are counter vailing economic arguments that could be used in support of rapid near term emissions abatement rational policy lies between these extremes a policy of deferring all emissions abatement exposes economic systems and industries as well as the environment to significantly greater costs and risks than those arising from a more balanced approach furthermore the modelling studies that have been used to justify deferring emissions abatement do so because they embody the economic factors favourable to delay and largely neglect the countervailing issues to the point where their results have little relevance to the overall problem of timing emissions abatement

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

the effect of low skilled immigration on u s prices evidence from cpi data i exploit the large variation across u s cities and through time in the relative size of the low skilled immigrant population to estimate the causal effect of immigration on prices of nontraded goods and services using an instrumental variables strategy i find that at current immigration levels a 10 percent increase in the share of low skilled immigrants in the labor force decreases the price of immigrant intensive services such as housekeeping and gardening by 2 percent wage equations suggest that lower wages are a likely channel through which these effects take place however wage effects are significantly larger for low skilled immigrants than for low skilled natives implying that the two are imperfect substitutes

on backstops and boomerangs environmental r d under technological uncertainty abstract in areas such as climate change the recent economic literature has been emphasizing and addressing the pervasive presence of uncertainty this paper considers a new and salient form of uncertainty namely uncertainty regarding the environmental characteristics of green innovations here rd ii a decreasing probability of finding a backstop leads to the toleration of higher pollution levels slower rd iii learning about the probability of a backstop is driven by failures only and leads to decreasing research incentives and iv small to moderate delays in the resolution of technological uncertainty do not affect the optimal policy

the regulation of international lending imf support the debt crisis and bank stockholder wealth abstract in a recent article cornell landsman and shapiro 1986 provide insight in to the impact of selected regulatory responses to the international debt crisis on bank stock prices the current study concentrates on the reaction of bank shareholders to the legislative events that ultimately led to the passage of the international lending supervision act ilsa and to greater u s support of the international monetary fund imf while cornell landsman and shapiro restricted their legislative analysis to when the relevant bills were passed this study also examines when such legislation was introduced in the house or the senate the empirical results indicate that the introduction of such legislation materially influenced bank stockholder expectations in contrast to cornell landsman and shapiro the effect of these events on the risk return complexion of banks is measured furthermore the sensitivity of bank stockholders reactions to the above legislative events is appraised in light of banks latin american loan portfolio risk analysis of the expected impact of greater imf support and the ilsa on bank stockholders supplements the work of cornell landsman and shapiro by providing additional insight into the expected impact of such legislation on bank industry risk unlike cornell landsman and shapiro this study provides evidence that the joint effect of a greater imf quota and the ilsa was a net benefit to stockholders analysis suggests that the perceived benefit of a greater imf quota was apparently diminished by the ilsa however stockholders evidently perceived a general decrease in the risk of the banking industry as a result of the legislative events

the brady plan the 1989 mexican debt reduction agreement and bank stock returns in the united states and japan the authors investigate the impact of the menu approach to debt rescheduling on the market value of two major creditors u s and japanese banks they try to understand how major creditor banks are affected by debt reschedulings and the menu choices they make so that debt deals can be structured in a way that appeals to both creditors and debtor countries they measure the stock market s reaction to the announcement of the brady plan and the mexican debt reduction agreement the brady plan was implemented through the menu approach which acknowledges creditor heterogeneity and provides financing packages that meet the country s financing requirements while still allowing the banks to reduce their exposure the mexican agreement provides an opportunity to test the impact of the brady plan s implementation by examining individual bank s menu choices exposure levels and the market s reaction they explore whether banks were able to make optimal portfolio choices when confronted with the obligation to participate they show that stock prices for different groups of banks reacted quite differently to focal events among all banks u s multinationals showed the strongest positive reaction to the brady announcement and the mexican agreement u s non multinationals do not appear to have been significantly affected by these international debt related events the reaction experienced by all japanese banks was much weaker than that of u s multinationals and was negative for the brady announcement and the initial mexico announcement the authors contend that the lack of a strong reaction was because of the japanese banks relatively low exposure to developing country risk they see the negative market reaction as a reflection of the expectation that a u s initiated debt reduction strategy would not be favorable for japanese banks indeed after the menu choices were announced the market recognized that the japanese banks were treated fairly and corrected itself they do not find that banks that made different choices were treated differently by the market so banks were able to negotiate menu choices in their best interest and to make portfolio choices consistent with their business objectives the results here confirm that the menu approach to debt restructuring may benefit both the creditor banks and the debtor countries

the impact of learning by doing on the timing and costs of co2 abatement abstract a particular ceiling on atmospheric co 2 concentrations can be maintained through a variety of emission pathways over the past decade there has been considerable debate over the characteristics of a least cost pathway some have suggested that a gradual departure from the emissions baseline will be the most cost effective because it reduces the pressure for premature retirement of the existing capital stock and it provides valuable time to develop low cost low carbon emitting substitutes others counter that a major flaw in analyses that support this line of reasoning is that they ignore learning by doing lbd in this paper we examine the impact of lbd on the timing and costs of emissions abatement with regard to timing we find that including learning by doing does not significantly alter the conclusions of previous studies that treated technology cost as exogenous the analysis supports the earlier conclusion that for a wide range of stabilization ceilings a gradual transition away from the no policy emissions baseline is preferable to one that requires substantial near term reductions we find that the major impact of including learning by doing is on the costs of emission abatement depending upon the sensitivity of costs to cumulative experience lbd can substantially reduce the overall costs of emissions abatement

scientific progress and irreversibility an economic interpretation of the precautionary principle abstract we consider the problem of the optimal use of a good whose consumption can produce damages in the future scientific progress is made over time that provides information on the distribution of the intensity of damages we show that this progress induces earlier prevention effort only if prudence is larger than twice absolute risk aversion this paper thus identifies the class of quite restrictive but plausible conditions such that scientific uncertainties justify an immediate reduction of the consumption of a potentially toxic substance

r d investment strategy for climate change abstract the economic costs of stabilizing greenhouse gas concentrations over the coming century depend critically on the development of new technologies in the energy sector our research and development r d investment strategy is the control variable for technology availability this paper proposes an analytic framework for determining optimal r d investment allocation and presents some numerical results to demonstrate the implementation of the methodology the value of technological advance in three targeted areas fossil based generation renewables and carbon capture and storage is represented by the increase in expected welfare in the presence of an emissions policy constraint of initially uncertain stringency r d expenditure increases the probability of advance optimal investment is determined by its relationship with success probability which is assumed to exhibit decreasing returns to scale relative to the value of success while the numerical results are speculative the paper offers insights into the nature of an optimal technology strategy for addressing climate change

monotone comparative statics under uncertainty this paper analyzes monotone comparative statics predictions in several classes of stochastic optimization problems the main results characterize necessary and sufficient conditions for comparative statics predictions to hold based on properties of primitive functions that is utility functions and probability distributions the results apply when the primitives satisfy one of the following two properties i a single crossing property which arises in applications such as portfolio investment problems and auctions or ii log supermodularity which arises in the analysis of demand functions affiliated random variables stochastic orders and orders over risk aversion

risk in international banking this paper differentiates between country risk the probability that a country will default on its obiigations and two forms of international banking risk 1 the extent to which a bank s foreign activities affect the cost of equity capital and 2 the extent to which a bank s foreign activities affect the probability of bankruptcy the paper focuses on the latter form of international banking risk using chebyshev s inequality it is pointed out that the risk of bankruptcy is influenced by the mean as well as the variance of the return distribution consequently restrictions on the international composition of a bank s portfolio may increase rather than reduce the probability of bankruptcy

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

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