economic growth and climate the carbon dioxide problem in contemplating the future course of economic growth in the west scientists are divided between one group crying wolf and another which denies that species existence one persistent concern has been that man s economic activities would reach a scale where the global climate would be significantly affected unlike many of the wolf cries this one in my opinion should be taken very seriously the present article will first give a brief overview of the climatic implications of economic activity with special reference to carbon dioxide and then will present possible strategies for control a more complete report with references to the literature on climatic change is contained in nordhaus 1976 it is thought that the economic activities which most affect climate are agriculture and energy of these the latter is probably more significant is certainly more easily analyzed and will be discussed here in the energy sector emissions of carbon dioxide particulate matter and heat are of significance for the global climate

robustness of a simple rule for the social cost of carbon abstract the optimal social cost of carbon is in general equilibrium proportional to gdp if utility is logarithmic production is cobb douglas depreciation is 100 every period climate damages as fraction of production decline exponentially with the stock of atmospheric carbon and fossil fuel extraction does not require capital the time profile and size of the optimal carbon tax corresponding to this simple rule are not robust to more convex climate damages smaller elasticities of factor substitution and non unitary coefficients of relative intergenerational inequality aversion the optimal timing of energy transitions and the amount of fossil fuel reserves to be locked up in the earth are also not accurately predicted by this framework still in terms of welfare and global warming the simple rule for the optimal social cost of carbon manages to get quite close to the first best

the role of finance in environmental innovation diffusion an evolutionary modeling approach abstract the implementation of climate adaptation and mitigation policies depend on the development of green technologies whose diffusion is constrained by a number of barriers which prevent them to spread broadly and at a fast pace by means of an agent based computational model the paper investigates the macro and micro economic dynamics considering the role of a traditional commercial bank and a state investment bank that explicitly supports green investments simulation results emphasize that green finance matter and that the market diffusion of environmental innovation is more pronounced when the presence of the public investment bank is combined with strong consumers preferences oriented towards environmental quality the relevance of the paper is twofold besides contributing to the literature on the finance innovation nexus by considering the role of climate finance within a complex systems framework it provides a model that can be used as a tool to explore policies to foster environmental innovation diffusion

the dynamic impact of unilateral environmental policies this paper builds a two country two sector polluting nonpolluting trade model with directed technical change examining whether unilateral environmental policies can ensure sustainable growth the emission rate of the polluting sector depends on its relative use of a clean and a dirty input a unilateral policy combining clean research subsidies and a trade tax can ensure sustainable growth while unilateral carbon taxes alone increase innovation in the polluting sector abroad and generally cannot ensure sustainable growth relative to autarky and exogenous technical change respectively trade and directed technical change accelerate environmental degradation either under laissez faire or with unilateral carbon taxes yet both help reduce environmental degradation under the appropriate unilateral policy i characterize the optimal unilateral policy analytically and numerically using calibrated simulations knowledge spillovers have the potential to reduce the otherwise large welfare costs of restricting policy to onecountry

factor adjustment spikes and interrelation an empirical investigation we take a descriptive look at interrelated factor demand starting from the observation that adjustment of capital and labor is lumpy we find that the adjustment dynamics of an input factor are affected by large adjustments in the other

climate policy under factor mobility a differentiated case for capital taxation abstract in a general equilibrium model with two periods and a finite fossil resource i analyze the non cooperative climate policies of symmetric countries that are in competition for mobile factors of production capital and fossil energy the paper shows that countries that want to slow down climate change but are also concerned about tax revenues from mobile tax bases have a rationale to supplement environmental taxes on fossil fuels with source based capital taxes or subsidies more specifically countries find it beneficial to subsidize capital in period one and tax it in period two the first period subsidy on capital facilitates a higher environmental tax by counteracting its adverse effects and increases national and global welfare in equilibrium by contrast the capital tax in period two induces inter and intratemporal distortions that lead to lower welfare the rate of resource extraction is inefficiently high in equilibrium no matter which tax portfolio is at the governments disposal furthermore unintended green paradox effects of demand side policies are shown to arise even in general equilibrium with factor mobility finally factor mobility does not necessarily lead to a higher rate of extraction and lower welfare compared to autarky

oil monopoly and the climate this paper takes as given that i the burning of fossil fuel increases the carbon dioxide content in the atmosphere which ii in turn leads to global heating and global climate change of a variety that iii on net is harmful to our welfare to answer questions about the policy implications of this a comprehensive and quantitative analysis of the two way interaction between the economy with its fossil fuel use and the climate is necessary in this paper however we focus on a particular aspect of this interaction the role played by the industrial organization in the oil producing sector of the world without a clear understanding of the world market for oil the consequences of taxes and other policy instruments cannot be evaluated analyses of the world oil market that are based on perfect competition and a finite amount of oil typically predict i that the oil price satisfies the hotelling rule i e increases so that the rate of return on storing oil is equal to the return on the capital market ii that oil consumption follows a decreasing path and iii that extraction is sequential in the sense that sources with lower extraction costs are depleted before high cost sources are used all these predictions are problematic to reconcile with data our main point here is that the polar opposite case where oil is supplied by a large agent with zero extraction costs who internalizes the effects of his decisions on all aggregates seems useful for understanding historic and future developments in the oil market

the welfare implications of climate change policy abstract the response to three different climate change policies is measured within a general equilibrium model of world output technological change greenhouse gas emissions and climate driven changes in productivity the proposed policies including an approximation to the kyoto protocol are shown to differ greatly in how they mitigate climate change support economic growth and allocate rents across generations benefits of alternative policies relative to the status quo do not necessarily accrue to the generations that bear the costs the results also show that the chosen rent distribution rule has a profound effect on policy evaluation in particular policies which allocate rents on a per capita basis are shown to be systematically welfare preferred to situations where emissions rights are grandfathered to emitting firms this implies that both the optimal level of emissions and the welfare cost of reaching a given target of emissions or atmospheric concentration would be lower under a per capita allocation of emissions permits or carbon tax revenues

non cooperative and cooperative responses to climate catastrophes in the global economy a north south perspective the optimal response to a potential productivity shock which becomes more imminent with global warming is to have carbon taxes to curb the risk of a calamity and to accumulate precautionary capital to facilitate smoothing of consumption this paper investigates how differences between regions in terms of their vulnerability to climate change and their stage of development affect the cooperative and non cooperative responses to this aspect of climate change it is shown that the cooperative response to these stochastic tipping points requires converging carbon taxes for developing and developed regions the non cooperative response leads to a bit more precautionary saving and diverging carbon taxes we illustrate the various outcomes with a simple stylized north south model of the global economy

optimal climate policies in a dynamic multi country equilibrium model abstract this paper develops a dynamic general equilibrium model with an arbitrary number of different regions to study the economic consequences of climate change under alternative climate policies regions differ with respect to their state of economic development factor endowments and climate damages and trade on global markets for capital output and exhaustible resources our main result derives an optimal climate policy consisting of an emissions tax and a transfer policy the optimal tax can be determined explicitly in our framework and is independent of any weights attached to the interests of different countries such weights only determine optimal transfers which distribute tax revenues across countries we infer that the real political issue is not the tax policy required to reduce global warming but rather how the burden of climate change should be shared via transfer payments between different countries we propose a simple transfer policy which induces a pareto improvement relative to the laissez faire solution a calibrated example quantifies pareto improving transfers between rich and poor countries

on the deliberative capacity of private multi stakeholder governance the roundtables on responsible soy and sustainable palm oil the democratic quality of private multi stakeholder governance is an important subject of academic and political debate on the one hand private multi stakeholder arrangements are seen as a way of democratizing international environmental governance on the other hand the democratic potential of these arrangements has been heavily criticized and interpreted as a privatization of what should be public to nuance this debate this paper assesses the democratic potential of one specific type of arrangement roundtables these roundtables are presented as being based on a deliberative democratic rationale this paper therefore assesses the deliberative capacity of the roundtables on responsible soy and sustainable palm oil and shows to what extent the communicative processes in these roundtables are inclusive consequential and authentic this paper concludes that the roundtable model tends to fall short on two criteria of deliberative democracy inclusiveness of actors and discourses and consequentiality

spatial climate economic models in the design of optimal climate policies across locations we couple a one dimensional energy balance climate model with heat transportation across latitudes with an economic growth model we derive temperature and damage distributions across locations and optimal taxes on fossil fuels which in contrast to zero dimensional integrated assessment models account for cross latitude externalities we analyze the impact of welfare weights on the spatial structure of optimal carbon taxes and identify conditions under which these taxes are spatially nonhomogeneous and are lower in latitudes with relatively lower per capita income populations we show the way that heat transportation affects local economic variables and taxes and locate sufficient conditions for optimal mitigation policies to have rapid ramp up initially and then decrease over time

which policy is more effective carbon reduction in all industries or in high energy consuming industries from dual perspectives of welfare effects and economic effects abstract carbon emission reduction policy is the main method to curb carbon emissions and tackle climate change however few studies have investigated the effectiveness of carbon emission reduction polices from the welfare and economic perspectives this study establishes a dynamic general equilibrium model with input output structure and compares the effects of emission reduction in all industries and in high energy consuming industries the main conclusions are that carbon emission reduction constraints for all industries have more significant negative impacts on consumption and social welfare compared to emission reduction constraints for high energy consuming industries to be more precisely carbon emission reduction in high energy consuming industries has comparative advantages in maintaining social welfare stability regarding economic effects compared with the carbon emission reduction in high energy consuming industries carbon emission reduction in all industries leads to a larger decline in total output and outputs of most industries however the role of carbon emission reduction in all industries is more significant in promoting employment the carbon emission reduction policies of all industries and high energy consuming industries have strengths in economic effects respectively the findings could provide references for the government to take appropriate measures to promote carbon emission reduction and economic growth

induced innovation and energy prices this paper uses u s patent data from 1970 to 1994 to study the impact of energy prices on energy efficient innovations theories of technological change have focused both on demand side factors which spur innovative activity by increasing the value of new innovations and supply side factors such as scientific advancements that make new innovations possible data on demand side factors are easily obtained but data on supply side factors that influence innovation are not readily available this paper uses patent citations as a measure of the usefulness of the existing base of scientific knowledge citations to previous patents are used to construct productivity estimates which measure the usefulness of the existing stock of knowledge to inventors in a given energy field for any given year these estimates are then combined with data on demand side factors to estimate a model of induced innovation in energy technologies the results indicate that both energy prices and the supply of knowledge have strongly significant positive effects on innovation the paper concludes with a discussion of the implication of this work for environmental policy

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

simple rules for climate policy and integrated assessment a simple integrated assessment framework that gives rules for the optimal carbon price transition to the carbon free era and stranded carbon assets is presented which highlights the ethical economic geophysical and political drivers of optimal climate policy for the ethics we discuss the role of intergenerational inequality aversion and the discount rate where we show the importance of lower discount rates for appraisal of longer run benefit and of policy makers using lower discount rates than private agents the economics depends on the costs and rates of technical progress in production of fossil fuel its substitute renewable energies and sequestration the geophysics depends on the permanent and transient components of atmospheric carbon and the relatively fast temperature response and we allow for positive feedbacks the politics stems from international free rider problems in absence of a global climate deal we show how results change if different assumptions are made about each of the drivers of climate policy our main objective is to offer an easy back on the envelope analysis which can be used for teaching and communication with policy makers

nonlinear response of firm investment to q abstract abel and eberly 1994 study optimal investment behavior in the presence of flow fixed costs proportional costs and convex costs a clear prediction is that investment will alternate between regimes of insensitivity and responsiveness to q separated by unknown threshold levels of q at the firm level we find evidence for different regimes of sensitivity to q but not for a regime of zero sensitivity our finding that investment has a nonlinear relationship to q is important because it implies an elasticity of aggregate investment to q and fundamentals that is high and variable over time

how should the distant future be discounted when discount rates are uncertain abstract the so called weitzman gollier puzzle is the fact that two seemingly symmetric and equally plausible ways of dealing with uncertain future discount rates appear to give diametrically opposed results the puzzle is resolved when agents optimize their consumption plans the long run discount rate declines over time toward its lowest possible value

the nobel memorial prize for william d nordhaus william d nordhaus and paul m romer received the 2018 sveriges riksbank prize in economic sciences in memory of alfred nobel this paper surveys nordhaus contributions on integrating climate change into long run macroeconomic analysis for which he was recognized with this prize

on the spatial economic impact of global warming we propose a dynamic spatial theory to analyze the geographic impact of climate change agricultural and manufacturing firms locate on a hemisphere trade is costly firms innovate and technology diffuses over space emissions from energy used in production contribute to the atmospheric stock of carbon which increases temperature warming differs across latitudes and its effect on productivity varies across sectors we calibrate the model to analyze how climate change affects the spatial distribution of economic activity trade migration growth and welfare we assess quantitatively the impact of migration and trade restrictions energy taxes and innovation subsidies

on modeling and interpreting the economics of catastrophic climate change with climate change as prototype example this paper analyzes the implications of structural uncertainty for the economics of low probability high impact catastrophes even when updated by bayesian learning uncertain structural parameters induce a critical tail fattening of posterior predictive distributions such fattened tails have strong im plications for situations like climate change where a catastrophe is theoretically possible because prior knowledge cannot place sufficiently narrow bounds on overall damages this paper shows that the economic consequences of fat tailed structural uncertainty along with unsureness about high temperature damages can readily outweigh the effects of discounting in climate change policy analysis

economics and climate change integrated assessment in a multi region world this paper develops a model that integrates the climate and the global economy an integrated assessment model with which different policy scenarios can be analyzed and compared the model is a dynamic stochastic general equilibrium setup with a continuum of regions thus it is a full stochastic general equilibrium version of rice nordhaus s pioneering multi region integrated assessment model like rice our model features traded fossil fuel but otherwise has no markets across regions there is no insurance nor any intertemporal trade across them the extreme form of market incompleteness is not fully realistic but arguably not a bad approximation of reality its major advantage is that along with a set of reasonable assumptions on preferences technology and nature it allows a closed form model solution we use the model to assess the welfare consequences of carbon taxes that differ across as well as within oil consuming and producing regions we show that surprisingly only taxes on oil producers can improve the climate taxes on oil consumers have no effect at all the calibrated model suggests large differences in views on climate policy across regions