the greenhouse effect damages costs and abatement the buildup of so called greenhouse gases in the atmosphere co2 in particular appears to be having an adverse impact on the global climate this paper briefly reviews current expectations with regard to physical and biological effects their potential costs to society and likely costs of abatement for a worst case scenario it is impossible to assess in economic terms the full range of possible non linear synergistic effects in the most favorable although not necessarily likely case of slow paced climate change however it seems likely that the impacts are within the affordable range at least in the industrialized countries of the world in the third world the notion of affordability is of doubtful relevance making the problem of quantitative evaluation almost impossible we tentatively assess the lower limit of quantifiable climate induced damages at 30 to 35 per ton of co2 equivalent worldwide with the major damages being concentrated in regions most adversely affected by sea level rise the non quantifiable environmental damages are also significant and should by no means be disregarded the costs and benefits of 1 reducing cfc use and 2 reducing fossil fuel consumption as a means of abatement are considered in some detail this strategy has remarkably high indirect benefits in terms of reduced air pollution damage and even direct cost savings to consumers the indirect benefits of reduced air pollution and its associated health and environmental effects from fossil fuel combustion in the industrialized countries range from 20 to 60 per ton of co2 eliminated in addition there is good evidence that modest e g 25 reductions in co2 emissions may be achievable by the u s and by implication for other countries by a combination of increased energy efficiency and restructuring that would permit simultaneous direct economic benefits savings to energy consumers of the order of 50 per ton of co2 saved a higher level of overall emissions reduction possibly approaching 50 could probably be achieved at little or not net cost by taking advantage of these savings we suggest the use of taxes on fossil fuel extraction or a carbon tax as a reasonable way of inducing the structural changes that would be required to achieve significant reduction in energy use and co2 emissions to minimize the economic burden and create a political constituency in support of the approach we suggest the substitution of resource based taxes in general for other types of taxes on labor income real estate or trade that are now the main sources of government revenue while it is conceded that it would be difficult to calculate the optimal tax on extractive resources we do not think this is a necessary prerequisite to policy making in fact we note that the existing tax system has never been optimized according to theoretical principles and is far from optimal by any reasonable criteria

how much damage will climate change do recent estimates two reasons to be concerned about climate change are its unjust distributional impact and its negative aggregate effect on economic growth and welfare although our knowledge of the impact of climate change is incomplete and uncertain economic valuation is difficult and controversial and the effect of other developments on the impacts of climate change is largely speculative the authors find that poorer countries and people are more vulnerable than are richer countries and people a modest global warming is likely to have a net negative effect on poor countries in hot climates but may have a net positive effect on rich countries in temperate climates if one counts dollars the world aggregate may be positive if one counts people the world aggregate is probably negative negative impacts would become more negative and positive impacts would turn negative for more substantial warming the marginal costs of carbon dioxide emissions are uncertain and sensitive to assumptions that partially reflect ethical positions but are unlikely to be larger than 50 per tonne carbon

competitive non linear pricing and bundling we examine the impact of multiproduct nonlinear pricing on profit consumer surplus and welfare in a duopoly when consumers buy all their products from one firm the one stop shopping model nonlinear pricing leads to higher profit and welfare but often lower consumer surplus than linear pricing by contrast in a unit demand model where consumers may buy one product from one firm and another product from another firm bundling generally acts to reduce profit and welfare and to boost consumer surplus in a more general model where consumers may buy from more than one firm and where consumers have elastic demands for each product nonlinear pricing has ambiguous effects compared with linear pricing nonlinear pricing tends to raise profit but harm consumer surplus when i demand is elastic ii there is substantial product differentiation iii there is substantial heterogeneity in consumer demand iv consumers face substantial shopping costs when visiting more than one firm and v a consumer s brand preference for one product is strongly correlated with her brand preference for another product nonlinear pricing is more likely to lead to welfare gains when i ii iv and v hold but iii does not

frontiers of climate change economics the economics of climate change is an active field of research the contributions to a special issue are put in context of the literature and it is suggested that second best issues such as carbon leakage and the green paradox need to be complemented with a political economy analysis of why certain instruments are politically infeasible and with intra and intergenerational analyses of the impact of climate policy a case is also made for more empirical work on the gradual and catastrophic damages of global warming

information exchange in policy networks information exchange in policy networks is usually attributed to preference similarity influence reputation social trust and institutional actor roles we suggest that political opportunity structures and transaction costs play another crucial role and estimate a rich statistical network model on tie formation in the german toxic chemicals policy domain the results indicate that the effect of preference similarity is absorbed by institutional relational and social opportunity structures political actors choose contacts who minimize transaction costs while maximizing outreach and information we also find that different types of information exchange operate in complementary but not necessarily congruent ways

multiple applications competing mechanisms and market power abstract we consider a labor market with search frictions in which workers make multiple applications and firms can post and commit to general mechanisms that may be conditioned both on the number of applications received and on the number of offers received by the firm s candidate when the contract space includes application fees there exists a continuum of symmetric equilibria of which only one is efficient and it has a posted wage equal to match output in the inefficient equilibria the wage is below match output and the value of a worker s application depends on whether he or she receives another offer this allows individual firms to free ride on one another and gives firms market power when we endogenize the number of applications and allow for general mechanisms only the efficient equilibrium survives by allowing for general mechanisms we are able to examine the sources of inefficiency in the multiple applications literature

are optimal emissions really optimal four critical issues for economists in the greenhouse although the greenhouse effect is by many considered as one of the most serious environmental problems several economic studies of the greenhouse effect most notably nordhaus s dice model suggest that it is optimal to allow the emissions of greenhouse gases ghg to increase by a factor of three over the next century other studies have found that substantial reductions can be justified on economic grounds this paper explores into the reasons for these differences and identifies four partly overlapping crucial issues that have to be dealt with when analysing the economics of the greenhouse effect low probability but catastrophic events cost evaluation methods the choice of discount rate the choice of decision criterion the paper shows that i these aspects are crucial for the policy conclusions drawn from models of the economics of climate change and that ii ethical choices have to be made for each of these issues this fact needs wider recognition since economics is very often perceived as a value neutral tool that can be used to provide policy makers with optimal policies

stochastic convenience yield and the pricing of oil contingent claims this paper develops and empirically tests a two factor model for pricing financial and real assets contingent on the price of oil the factors are the spot price of oil and the instantaneous convenience yield the parameters of the model are estimated using weekly oil futures contract prices from january 1984 to november 1988 and the model s performance is assessed out of sample by valuing futures contracts over the period november 1988 to may 1989 finally the model is applied to determine the present values of one barrel of oil deliverable in one to ten years time

welfare specifications and optimal control of climate change an application of fund the sensitivity of the optimal control of carbon dioxide emissions to the specification of the social welfare function is systematically explored using the fund model increasing risk aversion emphasises climate change damages relative to emission reduction costs but at the same time increases the discount rate of consumption without international co operation the discount rate effect dominates so that optimal control decreases with increasing risk aversion with international co operation optimal control first increases then decreases with increasing risk aversion since climate change falls heaviest on the poor optimal control increases with increasing inequity aversion full fledged intergenerational welfare functions on the one hand emphasise climate change damages but on the other hand place more weight on current poorer generations in fund the two tendencies almost cancel

network competition and interconnection with heterogeneous subscribers abstract this paper analyses two way access pricing in a telecommunications market where consumers are heterogeneous in their demand for calls and firms are allowed to use non linear tariffs we first investigate how the presence of access charges affects the tariffs offered by firms in symmetric equilibrium next we show that under certain conditions each firm s profit is independent of the level of reciprocal access charge and therefore collusion using access charges is not sustainable this result suggests that efficient call allocations can be achieved under a minimal regulatory intervention i e recommending firms set access charges equal to call termination cost

taxing fossil fuels under speculative storage long term environmental consequences of taxing fossil fuel usage have been extensively studied in the literature however these taxes may also impose several short run macroeconomic policy challenges the nature of which remains underexplored this paper investigates the mechanisms through which environmental taxes on fossil fuel usage can affect the main macroeconomic variables in the short run we concentrate on a particular mechanism speculative storage formulating and using a dynamic stochastic general equilibrium dsge model calibrated for the united states with an explicit storage facility and nominal rigidities we show that in designing environmental tax policies it is crucial to account for the fact that fossil fuel prices are subject to speculation the existence of forward looking speculators in the model improves the effectiveness of tax policies in reducing fossil fuel usage improved policy effectiveness however is costly it drives inflation and interest rates up while impeding output based on this tradeoff we seek an answer to the question how monetary policy should interact with environmental tax policies in our dsge model of fossil fuel storage we show that in an environment with no speculative storers monetary policy should respond to output along with cpi inflation in order to minimize the welfare losses brought by taxes however when the storage facility is activated responding to output in the monetary policy rule becomes less desirable

valuing the impact of co2 emissions valuing the impacts of co2 emissions to the atmosphere has been widely debated with various studies suggesting very different costs when expressed in units of dollar per tonne of carbon emitted there are many complex issues involved and it is often difficult to determine the reasons for the wide range of costs proposed in this paper models based on two very different approaches the page and intera models are considered by applying these models to calculating the marginal impact of co2 emissions it is shown that what appear initially to be divergent estimates can be reconciled this process illustrates some of the key issues in this area and a perspective is provided on which marginal costs are appropriate for different policy decisions

the damage costs of climate change a note on tangibles and intangibles applied to dice economic cost benefit analysis of the costs of greenhouse gas emission abatement and climate change often points towards limited abatement this note elucidates one reason why this result is obtained the way in which the intangible damages are treated and the utility function is specified on the basis of the dice model it is shown that by putting the intangible damages directly into the utility function and by assuming them to grow with per capita income the optimal reduction increases and in the second case more than triples compared to nordhaus s original results

economy wide estimates of the implications of climate change sea level rise the economy wide implications of sea level rise in 2050 are estimated using a static computable general equilibrium model this allows for a better estimate of the welfare effects of sea level rise than the common direct cost estimates and for an estimate of the impact of sea level rise on greenhouse gas emissions overall general equilibrium effects increase the welfare costs of sea level rise but not necessarily in every sector or region in the absence of coastal protection economies that rely most on agriculture are hit hardest although energy is substituted for land overall energy consumption falls with the shrinking economy hurting energy exporters with full coastal protection gdp increases particularly in regions with substantial dike building but utility falls least in regions that protect their coasts and export energy energy prices rise and energy consumption falls the costs of full protection exceed the costs of losing land the results also show direct costs the usual method for estimating welfare changes due to sea level rise are a bad approximation of the general equilibrium welfare effects previous estimates of the economic impact of sea level rise are therefore biased

on two part tariff competition in a homogeneous product duopoly abstract we explore aspects of two part tariff competition between duopolists providing a homogeneous service when consumers differ with respect to their usage levels competition in only one price component the fee or the rate may allow both firms to enjoy positive profits if the other price component has been set at levels different enough between firms fixing one price component alters the nature of competition indirectly introducing an element of product differentiation endogenous market segmentation emerges with the heavier users choosing the lower rate firm and the lighter users choosing the lower fee firm when no price component can be negative competition becomes softer profits tend to be higher but there is also a disadvantage for the firm that starts with a higher fee than that of its rival

the aggregation of climate change damages a welfare theoretic approach the economic value of environmental goods is commonly determined using the concepts of willingness to pay wtp or willingness to accept wta however the wtp wta observed in different countries or between individuals will differ according to socio economic characteristics in particular income this notion of differentiated values for otherwise identical goods say a given reduction in mortality risk has been criticized as unethical most recently in the context of the social cost chapter of the ipcc second assessment report these critics argue that being a function of income wtp wta estimates reflect the unfairness in the current income distribution and for equity reasons uniform per unit values should therefore be applied across individuals and countries this paper analyses the role of equity in the aggregation of climate change damage estimates using basic tools of welfare economics it shows one way of how wtp wta estimates can be corrected in aggregation if the underlying income distribution is considered unfair it proposes that in the aggregation process individual estimates be weighted with an equity factor derived from the social welfare and utility functions equity weighting can significantly increase aggregate global damage figures although some specifications of weighting functions also imply reduced estimates the paper also shows that while the postulate of uniform per unit values is compatible with a wide range of reasonable utility and welfare specifications there are also cases where the common value notion is not compatible with defensible welfare concepts

policy analysis of the greenhouse effect an application of the page model abstract in this paper we introduce a comprehensive model for policy analysis of the greenhouse effect page we apply the page model to assess the merits of policies to prevent global warming by controlling the emissions of greenhouse gases and policies to adapt to any global warming that occurs the results confirm that it is difficult to overcome the problem of global warming by taking preventive action alone the argument for introducing an aggressive adaptive policy is very strong we calculate the valuation that would have to be placed upon non economic environmental and social impacts for a combined strategy of preventive and adaptive policies to be considered a worthwhile option both for individual regions and for the world as a whole we also show that uncertainties in all four groups of inputs to the model scientific costs of control costs of adaptation and valuation of impacts have a great influence on the costs and impacts of the combined strategy

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

a general equilibrium analysis of climate change impacts on tourism this paper studies the economic implications of climate change induced variations in tourism demand using a world cge model the model is first re calibrated at some future years obtaining hypothetical benchmark equilibria which are subsequently perturbed by shocks simulating the effects of climate change we portray the impact of climate change on tourism by means of two sets of shocks occurring simultaneously the first set of shocks translate predicted variations in tourist flows into changes of consumption preferences for domestically produced goods the second set reallocate income across world regions simulating the effect of higher or lower tourists expenditure our analysis highlights that variations in tourist flows will affect regional economies in a way that is directly related to the sign and magnitude of flow variations at a global scale climate change will ultimately lead to a welfare loss unevenly spread across regions 2005 elsevier ltd all rights reserved

competitive price discrimination we model firms as supplying utility directly to consumers the equilibrium outcome of competition in utility space depends on the relationship u between profit and average utility per consumer public policy constraints on the deals firms may offer affect equilibrium outcomes via their effect on u f rom this perspective we examine the profit utility and welfare implications of price discrimination policies in an oligopolistic framework we also show that an equilibrium outcome of competitive nonlinear pricing when consumers have private information about their tastes is for firms to offer efficient two part tariffs

the welfare effects of the introduction of storage this paper examines the welfare effects of introducing storage into a market with stochastic supply in which all agents are competitive profit maximizers with rational expectations these welfare effects are the net result of the initial increase in demand for stock building and the partial and asymmetric reduction in the dispersion of consumption brought about by storage the distributional impacts depend crucially on the information available to producers before storage is introduced the elasticity of supply the specification of the consumption demand curve and the cost of storage

do current assessments underestimate future damages from climate change while the economic debate on climate policy focuses on discounting we do not know yet what to discount the potential non discounted socio economic cost of climate change indeed is still unknown only a few studies have tried to estimate socio economic costs of climate change most of them concluded that for a warming of a few degrees damages will be limited to a few percent of gdp all these studies however have disregarded important mechanisms and have only considered the cost of a stabilized new climate this article claims that the climate change issue should instead be framed in terms of the adaptation of socio economic systems to a changing climate doing so it calls for the taking into account of 1 the interaction between the uncertainty on future climate and the inertia of important economic sectors 2 the short term economic constraints that will be key in the response to climate shocks finally the impacts of climate change cannot be estimated assuming that societies will always be able to manage in a perfect way the subsequent change in risks as past experiences demonstrate our poor ability to do so these mechanisms suggest that the uncertainty on future climate change damages is even larger than is usually acknowledged and calls for additional research on climate change impacts

differences in interest rate policy at the ecb and the fed an investigation with a medium scale dsge model using two estimated models for the euro area and the united states this paper investigates whether the observed dierence in the amplitude of the interest rate cycle since 1999 in both areas is due to dierences in the estimated monetary policy reaction function dierences in the structure of the economy or dierences in the size and nature of the shocks hitting both economies the paper concludes that dierences in the type size and persistence of shocks in both areas can largely explain the dierent interest rate setting

unplanned purchases and retail competition i propose a framework in which consumers have biased beliefs about their future purchase probabilities leading them to make unplanned purchases us ing this framework i examine the phenomenon of below cost pricing and the welfare eects of banning it when the market is covered a ban on below cost pricing raises social surplus although consumers need not gain they are only guaranteed to ben et if the market is perfectly competitive when the market is not covered a ban always hurts at least some consumers also there is a pro competitive justica tion for the observation that larger rms sometimes charge below cost on the core product lines of smaller rms consumer bias is crucial for this justication multi product retailers sometimes sell certain products beneath cost with the hope of at tracting additional customers who will also buy other higher margin items this practice often referred to as loss leading is controversial with below cost pricing having been banned in a number of countries including belgium germany france and ireland and in approximately half of all us states 1 many us cities also have such prohibitions in this article i examine the welfare consequences of prohibitions on below cost pricing in a market where multi product retailers compete for boundedly rational consumers who practice one stop shopping that is visit at most one store when rivals are symmetric and the market is covered so that all consumers shop a ban on loss leading raises social surplus but when the market is not covered a ban presents a social welfare tradeo fewer consumers choose to shop although those who do generate higher levels of social surplus perhaps surprisingly for those consumers who shop both before and after a ban a ban is guaranteed to make them better o if the market is perfectly competitive but otherwise may harm them taken together these results indicate that it is simplistic to argue that by limiting the scope of competition below cost pricing bans must hurt consumers and society but i also assess below cost pricing laws in the presence of asymmetric competition as when a large rm with a full product line competes against a small rm with a limited product

the value of adaption climate change and timberland management abstract adaptation to exogenous change occurs on both intensive and extensive margins whether and how one accounts for human adaptation directly affects estimates of the economic consequences of environmental change estimates that are both critical in informing policy decisions and notoriously difficult to value this paper introduces and applies an analytical framework for placing an economic value on adaptation we explore the issue first in a stylized model that facilitates making concrete generalizations about the kinds of adaptations that generate high or low economic value we then test the soundness of our insights by incorporating learning and adaptive decision making into a structural dynamic forestry model where climate change is imposed exogenously and agents respond optimally using downscaled climate projections integrated with site and species specific timber productivity data we estimate the economic value of adaptation to climate change within the california timber industry we find on the intensive margin changing the rotation intervals will yield a low value of adaptation but on the extensive margin replanting more suitable tree species can yield significant value

production functions for climate policy modeling an empirical analysis abstract quantitative models for climate policy modeling differ in the production structure used and in the sizes of the elasticities of substitution the empirical foundation for both is generally lacking this paper estimates the parameters of 2 level ces production functions with capital labour and energy as inputs and is the first to systematically compare all nesting structures using industry level data from 12 oecd countries we find that the nesting structure where capital and labour are combined first fits the data best but for most countries and industries we cannot reject that all three inputs can be put into one single nest these two nesting structures are used by most climate models however while several climate policy models use a cobb douglas function for part of the production function we reject elasticities equal to one in favour of considerably smaller values finally we find evidence for factor specific technological change with lower elasticities and with factor specific technological change some climate policy models may find a bigger effect of endogenous technological change on mitigating the costs of climate policy

rethinking the costs related to global warming a survey of the issues one approach to the economic analysis of global warming seeks to balance the costs of damage from or adaptation to it with the costs of mitigating it the costs of adaptation and damage have been estimated using techniques of environmental evaluation but are subject to a wide margin of uncertainty the costs of mitigation principally by reducing the emissions of co2 have been estimated using different kinds of economic models some of the results of which have suggested that very little abatement of carbon emissions is justified before the costs of abatement exceed the benefits of it in terms of foregone damage and adaptation costs the paper analyses the extent to which this conclusion is a function of the modelling assumptions and techniques used rather than likely practical outcomes with regard to the models treatment of unemployed resources revenue recycling prior distortions in the economy due to the tax system and possible dynamic effects from the introduction of a carbon energy tax it concludes that with different and arguably more appropriate treatment of the above issues especially when the secondary benefits of reducing co2 emissions are also taken into account it is not clear that even substantial reductions in the use of fossil fuels will incur net costs especially if there is the prospect of even moderate costs from global warming

discounting and distributional considerations in the context of global warming the economics of global warming is reviewed with special emphasis on how the cost depends on the discount rate and on how costs in poor and rich regions are aggregated into a global cost estimate both of these factors depend on the assumptions made concerning the underlying utility and welfare functions it is common to aggregate welfare gains and losses across generations and countries as if the utility of money were constant but it is not if we assume that a e co2 equivalent dlubling implies costs equal to 1 5 of the income in both high and low income countries a pure rate of time preference equal to zero and a utility function which is logarithmic in income then the marginal cost of co2 emissions is estimated at 260 590 usd ton c for a time horizon in the range 300 1000 years an estimate which is large enough to justify significant reductions of co2 emissions on purely economic grounds the estimate is approximately 50 100 times larger than the estimate made by nordhaus in his dice model and the difference is almost completely due to the choice of discount rate and the weight given to the costs in the developing world as well as a more accurate model of the carbon cycle finally the sensitivity of the marginal cost estimate with respect to several parameters is analyzed

monetary valuation of the social cost of co2 emissions a critical survey an expanding branch of research has estimated the potential costs of climate change which are often expressed as the social cost of carbon scc or the costs of an additional ton of co2 emissions estimates of the scc can be used by policy makers to evaluate climate change policies and greenhouse gas emission reduction projects by means of cost benefit analyses cbas such analyses are complicated by the wide range of scc values that have been reported in the literature and the large uncertainties involved in estimating the potential economic impacts and related costs of climate change this study presents a critical review of the reported scc estimates by examining some neglected consequences of climate change uncertain and extreme scenarios of climate change the discounting of future climate change effects the treatment of individual risk aversion and assumptions about social welfare in view of the many uncertainties and omissions in conventional cost benefit analyses of climate impacts and the scc alternative approaches to decision making should be considered for climate policy

what do we learn from the price of crude oil futures summary despite their widespread use as predictors of the spot price of oil oil futures prices tend to be less accurate in the mean squared prediction error sense than no change forecasts this result is driven by the variability of the futures price about the spot price as captured by the oil futures spread this variability can be explained by the marginal convenience yield of oil inventories using a two country multi period general equilibrium model of the spot and futures markets for crude oil we show that increased uncertainty about future oil supply shortfalls under plausible assumptions causes the spread to decline increased uncertainty also causes precautionary demand for oil to increase resulting in an immediate increase in the real spot price thus the negative of the oil futures spread may be viewed as an indicator of fluctuations in the price of crude oil driven by precautionary demand an empirical analysis of this indicator provides evidence of how shifts in the uncertainty about future oil supply shortfalls affect the real spot price of crude oil copyright 2010 john wiley sons ltd

the social cost of carbon and its policy implications the shadow price or social cost of carbon is an important indicator of the global incremental damage done by emitting greenhouse gases today cost benefit analysis would set the optimal amount of greenhouse gas emission reduction at the point where this social cost just equals the incremental cost of controlling emissions the higher the value for the social cost of carbon the more control is warranted this comparison assumes that cost benefit analysis is the correct way of determining climate change policy and many believe this is not the case because of the very long term irreversible and potentially catastrophic nature of global warming but in the short run at least a comparison of cost and benefits is required and in any event all decisions imply costs and benefits but what is the right figure for the social cost of carbon this paper reviews the uk government s assessment of the cost and concludes that it has been set far too high because of a misreading of the integrated assessment models used to balance costs and benefits moreover adoption of the uk government s shadow price would have formidable implications for energy policy in the uk and for policies on afforestation copyright 2003 oxford university press

equitable cost benefit analysis of climate change greenhouse gas emissions and vulnerability to climate change show a strong negative correlation this is the moral issue at the heart of the climate problem however little attention has been paid to this in the literature see banuri et al 1996 for an overview the literature on equity issues in climate change is largely confined to the distribution of emissions reduction targets this literature takes the need to reduce greenhouse gas emissions for granted and takes a parametric approach to the required reductions on the other hand the literature that tries to derive how much emissions abatement is desirable largely ducks the equity issue this paper is an attempt to combine the two problems

oil prices and the terms of trade abstract the combination of substantial terms of trade variability and unstable correlation patterns of trade prices with output and trade volumes has led some to suggest a break in the link between trade volumes and prices we find that oil accounts for much of the variation in the terms of trade over the last twenty five years and its quantitative role varies significantly over time and since our dynamic general equilibrium model predicts that the economy responds differently to oil supply shocks than to other shocks changes in their relative importance helps to account for the unstable correlations in the data

estimates of the economic effects of sea level rise regional estimates of direct cost dc are commonly used to measure the economic damages of sea level rise such estimates suffer from three limitations i values of threatened endowments are not well known ii loss of endowments does not affect consumer prices and iii international trade is disregarded results in this paper indicate that these limitations can significantly affect economic assessments of sea level rise current uncertainty regarding endowment values as reflected in two alternative data sets for example leads to a 17 percent difference in coastal protec tion a 36 percent difference in the amount of land protected and a 36 percent difference in dc globally also global losses in equivalent variation ev a welfare measure that accounts for price changes are 13 percent higher than dc estimates regional ev losses may be up to 10 percent lower than regional dc however because international trade tends to redistribute losses from regions with relatively high damages to regions with relatively low damages

transnational markets for sustainable development governance the case of redd summary transnational sustainable development that is sustainable development policy initiatives involving actors in multiple countries often involves donor sponsorship of sustainable development projects similar to matching markets like venture capital employment searches or college admissions these transaction systems also known as matching markets can be seen in a variety of phenomena in transnational development governance including private aid public private sustainable development projects and transnational polycentric governance initiatives in this paper we utilize the matching market framework to develop a new approach to addressing an important question in development studies how do donors understood as donor agencies funds and foundations and firms choose which projects to support beginning with the observation that matching markets in sustainable development governance are heavily constrained by transaction costs in the absence of formal institutions that lower costs of searching monitoring and communicating with potential partners we hypothesize that both donors and project participants are motivated to utilize strategies to lower transaction costs of making connections which results in selection of projects based on the presence of transnational brokers or familiar partners or as part of a strategy of spatial specialization conceptualizing the choices made in this matching market as an affiliation network connecting donors to sponsored projects we utilize exponential random graph models of 91 funders support of 195 reducing emissions from deforestation redd and sustainable forest management pilot projects undertaken between 1989 and june 2012 to test the effects of transaction costs on donors choices of projects to sponsor we find that brokerage prior collaboration with the donor in question and spatial specialization all contribute to the ability of project proponents to attract funder support often outperforming relevant project characteristics such as carbon density and accessibility these findings suggest tensions between local scale project implementation and the transnational search for resource support observed qualitatively in the development studies literature can have significant effects on the overall structure of transnational collaboration on sustainable development

equitable cost benefit analysis of climate change policies the literature of welfare maximising greenhouse gas emission reduction strategies pays remarkably little attention to equity this paper introduces three ways to consider efficiency and equity simultaneously the first method inspired by kant and rawls maximises net present welfare without international cooperation as if all regions share the fate of the region affected worst by climate change optimal emission abatement varies greatly depending on the spatial and temporal resolution that is the grid at which maximum impact is defined the second method is inspired by varian s no envy emissions are reduced so as to equalise total costs and benefits of climate change over all countries of the world and over all time periods emission reductions are substantial this method approximately preserves the inequities that would occur in a world without climate change the third method uses non linear aggregations of welfare the utilitarian default is linear in a cooperative setting this method cannot distinguish between sources of inequity the higher the aversion to inequity the higher optimal greenhouse gas emission reduction

climate change costs recent advancements in the economic assessment climate change is unique among the consequences of fossil fuel burning in its far reaching impact both spatially and temporally earlier studies estimate the aggregated monetized damage due to climate change at 1 5 to 2 0 of world gdp for 2 co2 the oecd would lose 1 0 to 1 5 of gdp the developing countries 2 0 to 9 0 according to these estimates these figures are not comprehensive and highly uncertain newer studies increasingly emphasize adaptation variability extreme events other non climate change stress factors and the need for integrated assessment of damages as a result differences in impacts between regions and sectors have increased the market impacts in developed countries tended to fall and non market impacts have become increasingly important marginal damages are more interesting from a policy point of view earlier estimates range from about us 5 to us 125 per tonne of carbon with most estimates at the lower end of this range these figures are based on polynomial functions in the level of climate change but the rate of change may be equally important as are the speed of adaptation restoration and value adjustment furthermore future vulnerability to climate change will be different from current vulnerability on the whole the market impacts fall relatively with economic growth while the non market impacts rise relatively with growth

distributional biases in the analysis of climate change abstract the economic analysis of global warming is dominated by models based on optimal growth theory these representative agent models have an intrinsic distributional bias in favor of the rich the bias is compounded by the use of revenue neutrality in the allocation of emission permits the result is mitigation recommendations that are biased downwards

a social cost of carbon for almost every country this paper uses imputed national climate change impact functions to estimate national social costs of carbon which are largest in poor countries with large populations the national social costs of carbon of faster growing economies are less sensitive to the pure rate of time preference and more sensitive to the rate of risk aversion the pattern of national social costs of carbon is not sensitive to the assumed impact function climate sensitivity and scenario although the global social cost of carbon is income convergence raises the national social costs of carbon of poorer countries and lowers them for richer countries both global and national social costs of carbon are most sensitive to the income elasticity of climate change impacts a parameter about which we know little

gradual green tax reforms abstract green tax reforms have become an important tool not only in protecting the environment but also in bringing about a more efficient tax system however reforms often imply accepting sacrifices in the short run and bring about the risk of potential political opposition within this framework the debate on whether to implement green tax reforms in one step or gradually becomes of great interest in this paper we use a dynamic general equilibrium model calibrated to the spanish economy to evaluate different reforms that consist in increasing energy taxes and adjusting capital taxation in a revenue neutral framework our findings show that although an environmental dividend is always granted the existence of an efficiency dividend depends on the type of reform its size and how gradually it is implemented thus one step reforms that produce an efficiency dividend would imply large efficiency costs in the short run in this case the reform could only produce efficiency gains in the short run if it is implemented gradually although such gains would end up disappearing in the long run

watershed partnerships and the emergence of collective action institutions this paper examines the emergence of local cooperative institutions watershed partnerships that resolve collective action problems involved in the management of natural resources the political contracting approach to institutional supply suggests that watershed partnerships are more likely to emerge when potential benefits outweigh the transaction costs of developing and maintaining new institutions we analyze the impact of social political economic and ecological features of watersheds that affect benefits and transaction costs on the emergence of 958 watershed partnerships in the more than 2 100 watersheds in the united states our findings demonstrate that watershed partnerships are most likely to emerge in watersheds confronting severe pollution problems associated with agricultural and urban runoff with low levels of command and control enforcement and containing the resources to offset transaction costs

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

nonlinear pricing with random participation the canonical selection contracting programme takes the agent s participation decision as deterministic and finds the optimal contract typically satisfying this constraint for the worst type upon weakening this assumption of known reservation values by introducing independent randomness into the agents outside options we find that some of the received wisdom from mechanism design and nonlinear pricing is not robust and the richer model which allows for stochastic participation affords a more general empirical specification we develop a multidimensional methodology for addressing this class of problems providing two important applications to nonlinear pricing first with nonlinear pricing by a monopolist the familiar nodistortion at the top result persists but in tandem with the surprising conclusion that there is either no distortion at the bottom or bunching second in a simple model of product differentiated duopolists competing with nonlinear pricing we show that generally the duopoly outcome is qualitatively similar to the monopoly outcome however when marginal costs are symmetric and competition is sufficiently intense distortions disappear and the equilibrium outcome takes a remarkably simple form efficient quality allocations with cost plus fee pricing

optimal simple and implementable monetary and fiscal rules welfare maximizing monetary and fiscal policy rules are studied in a model with sticky prices money and distortionary taxation the ramsey optimal policy is used as a point of comparison the main findings are the size of the inflation coefficient in the interest rate rule plays a minor role for welfare it matters only insofar as it affects the determinacy of equilibrium optimal monetary policy features a muted response to output interest rate rules that feature a positive response to output can lead to significant welfare losses the welfare gains from interest rate smoothing are negligible optimal fiscal policy is passive the optimal monetary and fiscal rule combination attains virtually the same level of welfare as the ramsey optimal policy

carbon markets and technological innovation this paper examines the effects of firm level innovation in carbon abatement technologies on optimal cap and trade schemes with and without price controls we characterize optimal cap and trade regulation with a price cap and a price floor and compare it to the special cases of pure taxation and a simple emissions cap innovation shifts the tradeoff between price and quantity based instruments towards quantitybased emissions trading schemes more specifically an increase in innovation effectiveness lowers the optimal emissions cap and leads to relaxed price controls unless the slope of the marginal environmental damage curve is small because of the decrease in the emissions cap innovation in abatement technologies can lead to a higher expected carbon price so as to provide sufficient incentives for private r d investments the expected carbon price decreases once innovative technologies are widely used

international transmission of environmental policy a new keynesian perspective in this paper we examine the international transmission of environmental policy using a new keynesian model of the global economy we first consider the case in which the quality of the environment affects utility but not productivity this allows us to look at the trade off between environmental quality and output we then consider the case in which the quality of the environment increases productivity but does not affect utility our main results show that in both cases a unilateral implementation of a more stringent environmental policy by the domestic country raises foreign welfare under a benchmark parameterization our modeling strategy allows an analysis of how nominal rigidities interact with the implementation of environmental reforms by allowing the domestic country to shift through exchange rate depreciation parts of the costs of more stringent environmental policies to the foreign one

multilateral limit pricing in price setting games abstract in this paper we characterize the set of pure strategy undominated equilibria in differentiated bertrand oligopolies with linear demand and constant unit costs when firms may prefer not to produce when all firms are active there is a unique equilibrium however there is a continuum of non equivalent bertrand equilibria on a wide range of parameter values when the number of firms n is more than two and n 2 n 1 firms are active in each such equilibrium the firms that are relatively more cost or quality efficient limit their prices to induce the exit of their rival s when n 3 this game does not need to satisfy supermodularity the single crossing property or log supermodularity moreover the best responses might have negative slopes our main results extend to a stackelberg entry game where some established incumbents first set their prices and then a potential entrant sets its price

overlapping generations or infinitely lived agents intergenerational altruism and the economics of global warming do we need an overlapping generations model for the economics of global warming to answer this question an infinitely lived agent ila approach and an overlapping generations olg model are contrasted ila and olg can be viewed as polar representations of intergenerational altruism with ila an immortal agent acts through his investment savings decisions as trustee on the behalf of the future generations with olg agents need not behave altruistic they simply save during working years and dissave completely during retirement nevertheless ila and olg must not differ in their implication for greenhouse policy greenhouse gas abatement is a straightforward alternative to physical capital formation and even without altruism each age cohort has an incentive to provide current abatement in order to reduce future damages attributable to climate change indeed under reasonable assumptions and parameter values our simulations reveal such an invariance result provided carbon taxes are the only policy tool and tax revenues are recycled through socially mandated rules projections of economic growth climate change and energy consumption are only insignificantly affected by the choice of approach

the effects of ageing and an environmental trust fund in an overlapping generations model on carbon emission reductions most currently employed integrated assessment models for climate change are of a dynastic nature they employ the ramsey rule linking the interest rate economic growth and the rate of pure time preference this paper argues that although a dynastic framework might be convenient for economic analysis it is restrictive and can be misleading overlapping generations models which do not employ the ramsey rule are more flexible and may give results different from those derived from dynastic models with the integrated assessment model alice 2 0 it is shown how various assumptions on demographic change and public institutions can affect the interest rate thereby influencing the efficient greenhouse gas emission reductions it is concluded that dynastic integrated assessment models are in many respects inappropriate for providing policy makers with quantitative figures about the costs of carbon dioxide emissions and their desirable reduction levels 2001 elsevier science b v all rights reserved

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

on international equity weights and national decision making on climate change abstract estimates of the marginal damage costs of carbon dioxide emissions require the aggregation of monetised impacts of climate change over people with different incomes and in different jurisdictions implicitly or explicitly such estimates assume a social welfare function and hence a particular attitude towards equity and justice we show that previous approaches to equity weighting are inappropriate from a national decision maker s point of view because domestic impacts are not valued at domestic values we propose four alternatives sovereignty altruism good neighbour and compensation with different views on concern for and liability towards foreigners the four alternatives imply radically different estimates of the social cost of carbon and hence the optimal intensity of climate policy

optimal taxes on fossil fuel in general equilibrium we analyze a dynamic stochastic general equilibrium dsge model with an externality through climate change from using fossil energy our central result is a simple formula for the marginal externality damage of emissions or equivalently for the optimal carbon tax this formula which holds under quite plausible assumptions reveals that the damage is proportional to current gdp with the proportion depending only on three factors i discounting ii the expected damage elasticity how many percent of the output flow is lost from an extra unit of carbon in the atmosphere and iii the structure of carbon depreciation in the atmosphere thus the stochastic values of future output consumption and the atmospheric co2 concentration as well as the paths of technology whether endogenous or exogenous and population and so on all disappear from the formula we find that the optimal tax should be a bit higher than the median or most well known estimates in the literature we also formulate a parsimonious yet comprehensive and easily solved model allowing us to compute the optimal and market paths for the use of different sources of energy and the corresponding climate change we find coal rather than oil to be the main threat to economic welfare largely due to its abundance we also find that the costs of inaction are particularly sensitive to the assumptions regarding the substitutability of different energy sources and technological progress

product design in selection markets insurers choose plan characteristics to sort for profitable consumers in a model with multidimensional types this sorting incentive is proportional to the covariance among marginal consumers between marginal willingness to pay and cost to the insurer standard forms of cost sharing successfully repel costly consumers but reducing plan comprehensiveness instead alienates the risk averse in a perfectly competitive equilibrium the sorting incentive must vanish market power increases insurance quality and welfare nonetheless a competitive equilibrium with positive insurance is possible when insurance value is suciently negatively correlated with cost however in a calibration to handel hendel and whinston 2013 s data equilibrium still fails to exist

optimal dynamic carbon taxes in a climate economy model with distortionary fiscal policy how should carbon be taxed as a part of fiscal policy the literature on optimal carbon pricing often abstracts from other taxes however when governments raise revenues with distortionary taxes carbon levies have fiscal impacts while they raise revenues directly they may shrink the bases of other taxes e g by decreasing employment this article theoretically characterizes and then quantifies optimal carbon taxes in a dynamic general equilibrium climate economy model with distortionary fiscal policy first this article establishes a novel theoretical relationship between the optimal taxation of carbon and of capital income this link arises because carbon emissions destroy natural capital they accumulate in the atmosphere and decrease future output consequently this article shows how the standard logic against capital income taxes extends to distortions on environmental capital investments second this article characterizes optimal climate policy in sub optimal fiscal settings where income taxes are constrained to remain at their observed levels third this article presents a detailed calibration that builds on the seminal dice approach but adds features essential for a setting with distortionary taxes such as a differentiation between climate change production impacts e g on agriculture and direct utility impacts e g on biodiversity existence value the central quantitative finding is that optimal carbon tax schedules are 8 24 lower when there are distortionary taxes compared to the setting with lump sum taxes considered in the literature

external costs of energy do the answers match the questions looking back at 10 years of externe abstract while the claim for getting prices right is quite popular in conceptual policy papers the implementation of appropriate internalisation strategies is still hampered by a lack of reliable external cost data great expectations were set into the externe project a major research programme launched by the european commission at the beginning of the 1990s to provide a scientific basis for the quantification of energy related externalities and to give guidance supporting the design of internalisation measures after more than a decade of research the externe label became a well recognised standard source for external cost data looking back into the externe history the paper pursues how emerging new scientific insights and changing background assumptions affected external cost estimates and related recommendations to policy over time based on externe results the usefulness and inherent limitations of external cost estimates for impact categories like climate change or nuclear waste disposal is discussed the paper also gives examples on how external costs in spite of remaining uncertainties are successfully used to support environmental policy

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

the economic role of commodity storage one of the earliest and most successful exainples of economic policy is the oftquoted biblical account of joseph s interpretation of the pharoah s dream joseph foretold that seven years of abundant harvests would precede seven years of drought and recommended that the pharoah accumulate grain during the good years since that time the central role of storage in stabilising the economy in the face of exogenous disturbances has been obvious but our understanding of the nature of that role has not greatly advanced without divine assistance in forecasting stochastic production the storage decision is considerably more complex than the one joseph faced and the role of storage quite different in fact several commonly held impressions about the role of storage of commodities such as grains are incorrect rather than stabilising production storage actually accentuates its variability rather than causing a mean price preserving decrease or a mean output preserving decrease in the dispersion of price storage generally causes a more complex modification of the distribution of price rather than being most effective at eliminating short falls in consumption storage actually is more effective at eliminating the incidence of exceedingly high consumption in this paper we explore the role of storage in a model where production is stochastic and both production and storage are performed by competitive profitmaximisers who form rational expectations about the returns to their activities we derive the subtle but very important interactions among production price expectations and storage which simpler models cannot capture finally we make a comparative statics assessment of the distributional implications of storage these results while confirming the importance of the specification of the demand function and the supply elasticity identified in recent analytical studies e g wright i979 and newbery and stiglitz i979 are surprisingly favourable to consumers considering the asymmetric nature of the effects of storage on consumption and price storage is simply a productive activity one that transfers a commodity from one period to the next like other forms of production it is costly the total cost of storing an amount st from period t to period t i is as of period t i

collaboration patterns external shocks and uncertainty swiss nuclear energy politics before and after fukushima abstract energy shocks like the fukushima accident can have important political consequences this article examines their impact on collaboration patterns between collective actors in policy processes it argues that external shocks create both behavioral uncertainty meaning that actors do not know about other actors preferences and policy uncertainty on the choice and consequences of policy instruments the context of uncertainty interacts with classical drivers of actor collaboration in policy processes the analysis is based on a dataset comprising interview and survey data on political actors in two subsequent policy processes in switzerland and exponential random graph models for network data results first show that under uncertainty collaboration of actors in policy processes is less based on similar preferences than in stable contexts but trust and knowledge of other actors are more important second under uncertainty scientific actors are not preferred collaboration partners

spatial competition with price taking firms we consider a price taking equilibrium in the spatial setting a unique pricing equilibrium is shown to exist for any set of firm locations this equilibrium is then used to examine locational incentives in the two stage process in whiclh firms first choose locations anticipating the subsequent price taking outcome the result is spatial agglomeration if demand is inelastic and there are only two firms agglomeration does not occur if demand is too elastic or if there are more than two firms this paper presents a two stage model of spatial competition in which the prices in the second stage constitute a competitive equilibrium rather than being chosen by firms the analysis applies to an industry in which firms prices are regulated by an authority whose concern is to maximize social surplus as we show the prices the regulator would choose are those that would arise in the price taking equilibrium of course the full social optimum could be attained if the authority were also to regulate locations however apart from coarse restrictions such as zoning location regulation does not seem common in practice thus we model firms as deciding on the locations non cooperatively and anticipating correctly the subsequent price regulation for example when airlines were regulated they could choose the quality of their service such as departure times but price was controlled 2 the price taking equilibrium is also relevant even in the absence of regula tion when there are several suppliers at each location then the marginal cost curve associated with each point occupied by firms is simply interpreted as the supply curve the points occupied by suppliers can be thought of as market places or as shopping malls and the rents earned owing to increasing marginal costs can be extracted by the developer of the market place or mall the developer s location decision aims to maximize rents earned in choosing a location each developer takes into account how the ensuing price competition among suppliers both in the mall and across different malls affects the rents that can be extracted in this way locations are determined as a non cooperative equilibrium whereas prices are subsequently determined by walrasian competition we first assume that demand is completely inelastic and we prove the existence of a unique price equilibrium and that an allocation is optimal if and only if it can be supported by a price equilibrium the proofs do not require fixed point theorems and are a direct application of an intuitively appealing result of dubins and spanier 1961 we then extend our existence uniqueness and optimality results to allow for price sensitive demands different demand

two part tariff competition in duopoly abstract this paper develops two models of two part tariff competition when consumers are differentiated a la hotelling equilibrium prices equal marginal cost if and only if the demand of the marginal consumer equals the average demand entry fees are socially optimal in a symmetric equilibrium if all consumers participate in the market two part tariffs tend to result in lower prices higher profits and social welfare relative to uniform pricing in the logit model marginal cost pricing holds but entry fees are higher than socially optimal and two part tariffs lead to lower aggregate net consumer surplus but higher profits than uniform pricing

the economic effects of climate change greenhouse gas emissions are fundamental both to the world s energy system and to its food production the production of co2 the predominant gas implicated in climate change is intrinsic to fossil fuel combustion specifically thermal energy is generated by breaking the chemical bonds in the carbohydrates oil coal and natural gas and oxidizing the components to co2 and h2o one cannot have cheap energy without carbon dioxide emissions similarly methane ch4 emissions an important greenhouse gas in its own right are necessary to prevent the build up of hydrogen in anaerobic digestion and decomposition one cannot have beef mutton dairy or rice without methane emissions climate change is the mother of all externalities larger more complex and more uncertain than any other environmental problem the sources of greenhouse gas emissions are more diffuse than any other environmental problem every company every farm every household emits some greenhouse gases the effects are similarly pervasive weather affects agriculture energy use health and many aspects of nature which in turn affects everything and everyone the causes and consequences of climate change are very diverse and those in low income countries who contribute least to climate change are most vulnerable to its effects climate change is also a long term problem some greenhouse gases have an atmospheric life time measured in tens of thousands of years the quantities of emissions involved are enormous in 2000 carbon dioxide emissions alone and excluding land use change were 24 billion metric tons of carbon dioxide tco2

weight factors in cost benefit analysis of climate change equity considerations may justify the use of weight factors when estimating the costs of climate change this paper reviews different weight factors that have been used in the climate economics literature based on a simple model it is shown that although the different weight factors imply substantially different cost damage estimates they actually yield the same optimal emission reductions this paradox is explained by the fact that some of the approaches require that also the abatement costs are weighted and this offsets the effect of the diverging cost damage estimates the model is then used to analyse the importance weighting may have on the overall cost benefit analysis at present when most of the global emissions of fossil co2 originate from the industrialised countries the global optimal emissions are considerably lower if costs are weighted however the more the emissions in developing countries grow the less important becomes the introduction of weight factors in cost benefit analysis of climate change for the global emission reductions in the model developed here on a regional level the introduction of weight factors continues to play an important role implying substantially lower emissions in the rich region and slightly higher in the poor

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

transaction costs power and multi level forest governance in indonesia since 2005 there has been considerable international interest in reducing emissions from deforestation and forest degradation redd a program intended to finance protection of tropical forests through the sale of carbon offsets or from donor funding requiring the collaboration of local and international civil society stakeholders firms and donor and host governments redd is inherently a multi level governance project but to date participation in redd and coordination across governmental levels have been weak combining literature on multi level and polycentric governance of socioecological systems with transaction cost economics we argue that transaction costs structure cross level information sharing and collaboration relationships among organizations engaged in redd policy development at the national and provincial levels in indonesia using an exponential random graph modelling approach with data collected from interviews with over 80 organizations between 2010 and 2012 we find that powerful organizations tend to dominate cross level connections though this effect is somewhat mediated by organizational similarity which reduces transaction costs we suggest that explicit efforts to help local organizations overcome the transaction costs of building cross level relationships will be a central component of building an effective and equitable multi level governance system for redd in indonesia

climate change and insurance a critical appraisal several issues relating to insurance and the damage costs of climate change are discussed it is argued that the option of insuring climate change is severely limited because the associated damages are hardly quantifiable and little diversifiable in addition binding contracts are a problem on long time scales and in an international context hedging consumption smoothing over time precautionary investments and liability are not to be presented under the heading of insurance not only because this unnecessarily and confusingly expands the traditional definition of insurance but also because this could create a false sense of security the impact of climate change on the profitability of the commercial insurance sector is not likely to be severe as the insurance companies are capable of shifting changed risks to the insured provided that they are properly and timely informed on the consequences of climate change

oligopolistic competition and the optimal provision of products this paper considers the theory of market versus optimal product diversity in the light of two recent advances in oligopoly theory the first is the development of discrete choice models to describe heterogeneous consumer tastes and the application of such models to oligopolistic competition the second advance is the proof that logconcavity of the consumer taste density guarantees the existence of a price equilibrium we analyze an oligopoly model with price competition and free entry taking explicit account of the integer constraint under the chamberlinian symmetry assumption that tastes are i i d we first show that logconcavity of the taste density implies there is excessive market provision of variety when each consumer buys one unit of the product from one of the firms we then show that this result extends to price sensitive individual demands by proving that the equilibrium number of firms is at least as great as that which would be provided at the second best social optimum subject to a zero profit constraint for firms our results call into question previous findings for representative consumer models that left open the possibility of insufficient product diversity

network competition and entry deterrence we develop a model of logit demand that extends to a multi firm industry the traditional duopoly framework of network competition firstly we show that incumbents establish inefficiently the reciprocal access charge below cost when they compete in prices but they behave efficiently if they compete in utilities secondly we study how incumbents determine the industry wide access charge under the threat of entry we show that incumbents may accommodate all possible entrants only a group of them or may completely deter entry when entry deterrence is the preferred option incumbents distort the access charge upwards

competitive storage and commodity price dynamics by buying cheap and selling dear risk neutral commodity speculators can smooth commodity prices and induce serial dependence in price even when none would exist under a simple process of supply and demand commodity prices are variable and strongly positively correlated from one year to the next the variability is often explained by supply factors and the autocorrelation by the activities of speculators we show that this explanation is not consistent with the evidence speculation can substantially increase autocorrelation for prices that are weakly autocorrelated in its absence but not to the high levels that are observed in the data

from local to global competition abstract we introduce a framework that has known models of oligopolistic competition with differentiated products the circle the logit and the ces as limit cases this integrative approach incorporates both localized and global competition as well as price sensitive individual demands it is used to explain the impact of major changes over the last two centuries reductions in transport costs increased taste for variety population growth and use of technologies with greater returns to scale we work out the properties of an extended chamberlinian model with applications both in industrial organization and economic geography

network competition i overview and nondiscriminatory pricing we develop a model of unregulated competition between interconnected networks and analyze the mature and transition phases of the industry in this deregulated environ ment networks pay negotiated or regulated access charges to each other and com pete in prices for customers we show that a competitive equilibrium may fail to exist for large access charges or for large network substitutability and that freely negotiated access charges may prevent effective competition in the mature phase of the industry and erect barriers to entry in the transition toward competition last we examine the meaning and impact of policies such as the efficient component pricing rule

the impact of climate change on the balanced growth equivalent an application of fund the stern review added balanced growth equivalents bge to the economic climate change research agenda we first propose rigorous definitions of the bge for multiple regions and under uncertainty we show that the change in the bge is independent of the assumed scenario of per capita income for comparable welfare economic assumptions as the stern review we calculate lower changes in bge between a business as usual scenario and one without climate impacts with the model fund than the stern review found with the model page we find that mitigation policies give even lower changes in bge and argue that those policy choices should be the focus of the research effort rather than total damage estimates according to our results the current carbon tax should be below 55 tc sensitivity analyses show that the stern review chose parameters that imply high impact estimates however for regionally disaggregated welfare functions we find changes in bge that are significantly higher than the results from the stern review both for total damage as for policy analysis with regional disaggregation and high risk aversion we observe fat tails and with that very high welfare losses

a review of the stern review on the economics of climate change how much and how fast should we react to the threat of global warming the stern review argues that the damages from climate change are large and that nations should undertake sharp and immediate reductions in greenhouse gas emissions an examination of the review s radical revision of the economics of climate change finds however that it depends decisively on the assumption of a near zero time discount rate combined with a specific utility function the review s unambiguous conclusions about the need for extreme immediate action will not survive the substitution of assumptions that are consistent with today s marketplace real interest rates and savings rates

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

competition for exclusive customers comparing equilibrium and welfare under one part and two part pricing this paper compares one part pricing and two types of two part pricing in a general discretecontinuous choice model providing more extensive welfare results than prior literature under two part pricing rms may set xed fees with or without unit price commitment when unitprice commitment is present both xed fees and unit prices are set before consumers choose their exclusive suppliers in the absence of unit price commitment consumers choose exclusive suppliers based on known xed fees and anticipated future unit prices resulting in high unit prices consistent with models of aftermarket monopolization of the three possible pricing policies we nd that two part pricing with unit price commitment is rms dominant unilateral pricing policy and it also yields the highest joint pro ts under appropriate demand assumptions in terms of both consumer and social welfare two part pricing without unit price commitment is dominated by the other pricing policies with su ciently elastic usage demand and su ciently small customerspeci c xed costs one part pricing produces the highest consumer and social welfare but the lowest rm pro ts of the three pricing policies jel classi cation l1 d4 keywords two part pricing aftermarket monopolization bertrand competition discrete continuous random utility model

the damage costs of climate change towards a dynamic representation economic assessments of climate change impacts are commonly presented as the effect of a climate change associated with a doubling of the atmospheric concentration of carbon dioxide on the current economy this paper is an attempt to express impact as a function of both climate change and socio economic change with regard to climate change issues discussed are level versus rate of change speed of adaptation speed of restoration and value adjustment and symmetry with regard to socio economic change agriculture migration and the valuation of intangible losses are addressed uncertainty and higher order impacts are treated briefly it is qualitatively argued and quantitatively illustrated that these issues matter a great deal for the damage profile over the next century a damage model based on my best guesses is presented in the appendix