where do markets come from production markets have two sides producers are a fully connected clique transacting with buyers as a separate but aggregated clique each producer is a distinctive firm with a distinctive product each side continually monitors reactions of the other through the medium of a joint social construction the schedule of terms of trade each producer is guided in choice of volume by the tangible outcomes of other producers not by speculation on hypothetical reactions of buyers to its actions each producer acts purely on self interest based on observed actions of all others summarized through a feedback process the summary is the terms of trade schedule which reduces to constant price only in limiting cases the market emerges as a structure of roles with a differentiated niche for each firm explicit formulae both for firms and for market aggregates are obtained by comparative statics methods for one family of assumptions about cost structures and about buyers evaluations of differentiated products not just any set of firms can sustain terms of trade with any set of buyers there prove to be three main kinds of markets and three sorts of market failure within a parameter space that is specified in detail one sort of market paradox has a madison avenue flavor another is more conventional grind and a third crowded is a new form not included in any existing theory of markets current american industrial markets are drawn on for 20 illustrations of which three are presented in some detail inequality in firms market shares measured by gini coefficients is discussed

endogenous growth convexity of damage and climate risk how nordhaus framework supports deep cuts in carbon emissions to slow or not to slow nordhaus 1991 was the first economic appraisal of greenhouse gas emissions abatement and founded a large literature on a topic of worldwide importance we offer our assessment of the original article and trace its legacy in particular nordhaus s later series of dice models from this work many have drawn the conclusion that an efficient global emissions abatement policy comprises modest and modestly increasing controls we use dice itself to provide an initial illustration that if the analysis is extended to take more strongly into account three essential elements of the climate problem the endogeneity of growth the convexity of damage and climate risk optimal policy comprises strong controls

irreversible investment with regime shifts under the real options approach to investment under uncertainty agents formulate optimal policies under the assumption that firms growth prospects do not vary over time this paper proposes and solves a model of investment decisions in which the growth rate and volatility of the decision variable shift between different states at random times a value maximizing investment policy is derived such that in each regime the firm s investment policy is optimal and recognizes the possibility of a regime shift under this policy investment is intermittent and increases with marginal q moreover investment typically is very small but in some states the capital stock jumps implications for marginal q and the user cost of capital are also examined

scientific ambiguity and climate policy economic evaluation of climate policy traditionally treats uncertainty by appealing to expected utility theory yet our knowledge of the impacts of climate policy may not be of sufficient quality to be described by unique probabilistic beliefs in such circumstances it has been argued that the axioms of expected utility theory may not be the correct standard of rationality by contrast several axiomatic frameworks have recently been proposed that account for ambiguous knowledge in this paper we apply static and dynamic versions of a smooth ambiguity model to climate mitigation policy we obtain a general result on the comparative statics of optimal abatement and ambiguity aversion and then extend our analysis to a more realistic dynamic setting where we introduce scientific ambiguity into the well known dice model of the climate economy system for policy relevant exogenous mitigation policies we show that the value of emissions abatement increases as ambiguity aversion increases and that this ambiguity premium can in some plausible cases be very large in these cases the effect of ambiguity aversion on welfare is comparable to that of other much studied welfare parameters thus ambiguity aversion may be an important neglected aspect of climate change economics and seems likely to provide another argument for strong abatement policy

regional climate change policy under positive feedbacks and strategic interactions the surface albedo feedback along with heat and moisture transport from the equator to the poles is associated with polar amplification which is a well established scientific fact the present paper extends brock and xepapadeas in eur econ rev 94 263 282 2017 to a non cooperative framework with polar amplification where regions decide emissions by maximizing own welfare this can be regarded as a case of regional non cooperation regarding climate change open loop and feedback solutions are derived and compared in terms of temperature paths and welfare with the cooperative solution carbon taxes which could bridge the gap between cooperative and non cooperative emissions path are also derived finally the framework is extended to a ramsey set up in which it is shown how the regional climate model can be coupled with standard optimal growth models numerical simulations confirm the theoretical results and provide insights about the size and the direction of deviations between the cooperative and the non cooperative solutions

industrialization of agriculture discussion agricultural economists as story tellers focus on key players their motivations and activities mccloskey thus we try to understand current events in terms of the past and to peer into the future the better stories provide insights by pointing out and perhaps measuring relationships among events and causes coffey s story focuses on the impacts of industrialization on farm supply firms and particularly cooperatives coffey s story has the ring of authenticity of a person who knows his industry barkema and o brien attempt larger stories about the whole system today s growing fragmentation of consumer demand is barkema s driving force of change o brien s driving force is the effort to minimize or transfer risk

climate change policy under polar amplification abstract polar amplification is an established scientific fact which has been associated with the surface albedo feedback and with heat and moisture transport from the equator to the poles in this paper we unify a two box climate model which allows for heat and moisture transport from the southern region to the northern region with an economic model of welfare optimization our main contribution is to show that by ignoring spatial heat and moisture transport and the resulting polar amplification the regulator may overestimate or underestimate the tax on greenhouse gas emissions the direction of bias depends on the relations between marginal damages from temperature increase in each region we also determine the welfare cost when a regulator mistakenly ignores polar amplification numerical simulations confirm our theoretical results while ballpark estimates indicate that the tax bias could be as high as 20 while welfare cost could reach 2 of global effective steady state consumption

a portfolio approach to climate investments capm and endogenous risk is there a role for investments in climate change mitigation despite low expected return we use a model of intertemporal expected utility maximisation to analyse this question similar to the capital asset pricing model capm the rate of return depends on the correlation of risk between the return on investments in climate change mitigation and the market portfolio but in contrast to the classical capm we admit the fact that economic and environmental systems are jointly determined implying that environmental risk is endogenous therefore investments in climate change mitigation may reduce risk via self protection and self insurance if risk reduction is accounted for in cost benefit evaluations climate investments may be justified despite low expected return these aspects of climate investments are not however communicated via standard cost benefit analyses of climate policy optimal climate policy may therefore be more ambitious than previously considered

pricing carbon and adjusting capital to fend off climate catastrophes the optimal reaction to a potential productivity shock as a consequence of climate tipping is to substantially tax carbon in order to curb the risk of tipping but to adjust capital as well in order to smooth consumption when tipping occurs we also allow for conventional marginal climate damages and decompose the optimal carbon tax in two catastrophe components and the conventional component we distinguish constant and increasing marginal hazards moreover the productivity catastrophe is compared with recoverable catastrophes and with a shock to the climate sensitivity finally we allow for investments in adaptation capital as an alternative to counter the potential adverse effects of climate tipping quantitatively the results are investigated with a calibrated model for the world economy

as bad as it gets how climate damage functions affect growth and the social cost of carbon the paper analyzes the effects of varying climate impacts on the social cost of carbon and economic growth we use polynomial damage functions in a model of an endogenously growing two sector economy the framework includes nonrenewable natural resources which cause greenhouse gas emissions pollution stock harms capital and reduces economic growth we find a big effect of the selected damage function on the social cost of carbon and a significant impact on the growth rate in our calibration a quartic damage function raises the social cost of carbon by more than a factor of ten compared to the linear function in the social optimum the growth rate remains positive even when the damage function is highly convex we test the robustness of the results by adding pollution decay lowering the elasticity of intertemporal substitution and addressing uncertainty which does not alter our results we find that high marginal climate damages require stringent climate policies but do not preclude positive economic growth despite convexity provided that policies are designed in an efficient manner

pollution control under a possible future shift in environmental preferences abstract we examine how the possibility of a future shift in environmental preferences affects optimal pollution emissions for example is a more stringent carbon cap called for if excessive carbon emissions today may trigger a shift toward greener preferences in the future in contrast to the related literature which largely focuses on regime shifts in damages not preferences we find that the possibility of a shift in environmental preferences can induce higher or lower optimal current emissions this hinges on an economically interesting interplay between the magnitude of the possible shift whether the shift is endogenous and the magnitude of environmental damages this helps reconcile the tension between the conservationists view of pollution reduction to reduce damage and lessen the likelihood of regime shift and the traditional economic rationale emphasizing risk and discounting

asymmetric selection among organizations we discuss the creation of organizations and their survival as distinct selection processes and consider the significance of their divergence in particular to understand the implications of entrepreneurial booms we propose the possibility of asymmetric selection where entry selection and exit selection differ from each other in strength an observed increase in founding rates hence may reveal a decline in the selection threshold for entry implying lower average fitness among boom time entrants when such an expansion occurs organizations born during these periods of heightened entry should suffer higher failure rates if the fitness threshold required for survival remains stable or becomes more stringent we also discuss other processes that might educe founding waves and explain the different implications of these accounts for our empirical model estimates of the model support our theory of asymmetric selection in two out of three markets using a comprehensive dataset describing organizations in the us computer industry copyright 2003 oxford university press

welfare measurement under threats of environmental catastrophes abstract welfare measures under threats of environmental catastrophes are studied using the parable apparatus of weitzman and lofgren on the welfare significance of green accounting as taught by parable j environ econ manage 32 1997 139 153 the occurrence probability of the catastrophic events is driven at least partly by anthropogenic activities such as natural resource exploitation without external effects the green nnp is a genuine welfare measure vis a vis a particular parable economy often however the occurrence hazard constitutes a public bad treated as an externality by agents who ignore their own contribution to its accumulation in such cases the green nnp although accounting for the event hazard rate per se fails to properly internalize future effects on the hazard rate of current economic activities and as a result overestimates welfare the bias term associated with the green nnp is derived and expressed in a simple and interpretable form

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

nuclear power externalities and non standard pigouvian taxes the external effects arising from the use of nuclear power are in a fundamental way related to uncertainty in this paper we locate these external effects and derive a dynamic pigouvian tax in order to make the decentralized economy support the command optimum another interesting result is that a small constant energy tax which we interpret as a second best policy can take the decentralized economy reasonably close to the command optimum

agon and ag ec styles of persuasion in agricultural economics it is a tradition that these addresses be given by an outsider i speak as an outsider in praise of agricultural economics an outsider presuming to praise could be accused of condescension but i assure you i come by a favorable opinion of the field honestly i am practically an insider maternal relations own farms in illinois near watseka the same roger gray of the food research institute whom president elect johnston mentions in his paper is my second cousin once removed in england i have worked as an agricultural laborer once in vermont i milked a cow ag econ is in my blood

climatic tipping points and optimal fossil fuel use the economics of climate change is characterized by many uncertainties regarding for instance climate dynamics economic damages and potentially irreversible climate catastrophes using an optimal growth model of a fossil fuel driven economy subject to climate externalities and potentially irreversible climatic regime shifts this paper contributes to the understanding of how the risk of such events impacts on optimal fossil fuel use carbon taxes and fossil fuel prices over time we show that in excess to an increase in the expected present value of marginal damages and an increase in the probability of triggering the event there also exists a third opposing effect this effect comes from the fall in value of remaining fossil fuel reserve which results from the potential regime shift which may or may not occur sometime in the future and implies that optimal fossil fuel policy shifts towards using more resources early on this effect is related to the idea of the green paradox we prove the existence of this effect and show under which circumstances it can become quantitatively important numerically the green paradox effect seems to be somewhat smaller than but comparable in size to the increase in expected marginal damages in general our findings highlight the importance of considering the supply side impacts on climate policy in response to catastrophic climate events

energy balance climate models and general equilibrium optimal mitigation policies in a general equilibrium model of the world economy we develop a two dimensional energy balance climate model featuring heat diffusion and anthropogenic forcing driven by global fossil fuel use across the sphere of the earth this introduces an endogenous location dependent temperature function driving spatial characteristics in terms of location dependent damages resulting from local temperature anomalies into the standard climate economy framework we solve the social planner s problem and characterize the competitive equilibrium for two polar cases differentiated by the degree of market integration we define optimal taxes on fossil fuel use and how they may implement the planning solution our results suggest that if the implementation of international transfers across latitudes is not possible then optimal taxes are in general spatially non homogeneous and may be lower at poorer latitudes the degree of spatial differentiation of optimal taxes depends on heat transportation by employing the properties of the spatial model we show by numerical simulations how the impact of thermal transport across latitudes on welfare can be studied

averting catastrophes the strange economics of scylla and charybdis faced with numerous potential catastrophes nuclear and bioterrorism mega viruses climate change and others which should society attempt to avert a policy to avert one catastrophe considered in isolation might be evaluated in cost benefit terms but because society faces multiple catastrophes simple cost benefit analysis fails even if the benefit of averting each one exceeds the cost we should not necessarily avert them all we explore the policy interdependence of catastrophic events and develop a rule for determining which catastrophes should be averted and which should not jel d61 q51 q54

how optimal distinctiveness affects new ventures failure risk a contingency perspective abstract in this article we apply the concept of optimal distinctiveness to test whether category spanning has a nonlinear effect on new ventures risk to fail we argue that by being optimally distinct i e by attaining a level of category spanning that allows new ventures to benefit from balancing the competing needs of conformity with and differentiation from competitors new ventures can improve their survival chances in addition we argue that the relevance of optimal distinctiveness varies with a venture s age and a category s density we tested our hypotheses using data from 1668 metal bands that were founded in the united kingdom between 1967 and 2005 the results indicate that optimal distinctiveness is relevant to new ventures failure risk moreover we show that venture age attenuates the relevance of optimal distinctiveness whereas category density strengthens that factor s relevance

the persistence of lenient market categories research across disciplines presumes that market categories will have strong boundaries categories without well defined boundaries typically are not useful and so are expected to fade away we suggest many contexts contain lenient market categories or less constraining market categories that persist and become important we argue that this fact can be explained by looking at market categories from the producer perspective lenient market categories have more flexibility and allow for a wider range of fit as a result we expect to see high rates of entry into lenient categories at the same time lenient market categories have drawbacks they do not clearly convey what an organization does and do not identify specific sets of potential consumers this means organizations are more likely to exit when entry rates are higher than exit rates lenient market categories will endure over time we also predict that organizations exiting lenient categories will enter other lenient categories further fueling the persistence of such categories finally this trend is exaggerated when influential external agents favor leniency we find support for these ideas in a longitudinal analysis of organizational entry into and exit from market categories in the software industry

hedging your bets explaining executives market labeling strategies in nanotechnology executives use market labels to position their firms within market categories yet this activity has been given scarce attention in the extant literature that widely assumes that market labels are simple prescribed classification brackets that accurately represent firms characteristics by examining how and why executives use the nanotechnology label we uncover three strategies claiming disassociating and hedging comparing these strategies to firms technological capabilities we find that capabilities alone do not explain executives label use instead the data show that these strategies are driven by executives aspiration to symbolically influence their firms market categorization in particular executives perception of the label s ambiguity their avoidance of perceived credibility gaps and their assessment of the label s signaling value shape their labeling strategies in contrast to extant research which suggests that executives should aim for coherence we find that many executives hedge their affiliation with a nascent market label thus our study shows that in ambiguous contexts noncommitment to a market category may be a particularly prevalent strategy

managing the endogenous risk of disease outbreaks with non constant background risk there is a growing concern that risks of disease outbreak and pandemics are increasing over time we consider optimal investments in prevention before an outbreak using an endogenous risk approach within an optimal control setting using the threat of pandemic influenza as an illustrative example we demonstrate that prevention expenditures are relatively small in comparison to the potential losses facing the usa and these expenditures need to be flexible and responsive to changes in background risk failure to adjust these expenditures to changes in background risk poses a significant threat to social welfare into the future

the economy climate change and infectious diseases links and policy implications this short paper provides a modeling framework for unifying the economy climate change and the outbreak of infectious diseases such as the recent covid 19 pandemic we stress that continuous growth of consumption activities capital accumulation and climate change could increase the potential of the epidemic its contact number or the probability of its arrival this framework of analysis allows us to think of infectious disease policies in two stages in the short run containment policies like social distancing could help to stop the epidemic in the medium and the long run economic policies could help to reduce the potential of the epidemic or the probability of its emergence

why the far distant future should be discounted at its lowest possible rate abstract a critical feature of the distant future is currently unresolvable uncertainty about what will then be the appropriate rate of return on capital to use for discounting this paper shows that there is a well defined sense in which the lowest possible interest rate should be used for discounting the far distant future part of any investment project some implications are discussed for evaluating long term environmental projects or activities like measures to mitigate the possible effects of global climate change

does the optimal size of a fish stock increase with environmental uncertainties we analyze the effect of environmental uncertainties on optimal fishery management in a bio economic fishery model unlike most of the literature on resource economics but in line with ecological models we allow the different biological processes of survival and recruitment to be affected differently by environmental uncertainties we show that the overall effect of uncertainty on the optimal size of a fish stock is ambiguous depending on the prudence of the value function for the case of a risk neutral fishery manager the overall effect depends on the relative magnitude of two opposing effects the convex cost effect and the gambling effect we apply the analysis to the baltic cod and the north sea herring fisheries concluding that for risk neutral agents the net effect of environmental uncertainties on the optimal size of these fish stocks is negative albeit small in absolute value under risk aversion the effect on optimal stock size is positive for sufficiently high coefficients of constant relative risk aversion

beyond categorization new directions for theory development about entrepreneurial internationalization categorizations emphasizing the earliness of internationalization have long been a cornerstone of international entrepreneurship research here we contend that the prominence of categories has not been commensurate with theory development associated with them we draw on categorization theory to explain why earliness based categories are persistent and argue that a greater focus on notions related to opportunity can open new avenues of research about the entrepreneurial internationalization of business we propose and discuss three directions for opportunity based research on entrepreneurial internationalization involving context dynamics and variety

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

a framework to facilitate institutional arrangements for smallholder supply in developing countries an agribusiness perspective the industrialization of agriculture and the potential problem of small scale farmer marginalization calls for a fresh approach to the design of agribusiness supply chain arrangements in developing countries the objective of the paper is to contribute to a better understanding of institutional arrangements that can promote stable smallholder agribusiness contracting arrangements in a developing country context a case study approach incorporating a transaction cost framework is used to test whether trust can significantly change the contract characteristics of supply the results suggest that although the presence of trust can influence the contract characteristics of a supply arrangement it may not be significant because of other factors in a developing country context bearing this in mind a number of institutional arrangements are recommended in order to promote more stable contract conditions

consumption pollution tradeoffs in an environment vulnerable to pollution related catastrophic collapse abstract this paper considers the consequences of an avoidable risk of irreversible environmental catastrophe for society s optimal long run consumption pollution tradeoffs the risk is assumed to be a nondecreasing function of pollution concentration which evolves as a dynamic environmental renewal process the main objective of the paper is to derive qualitative insights regarding the effects of such risk on optimal management

abrupt positive feedback and the social cost of carbon optimal climate policy should act in a precautionary fashion to deal with tipping points that occur at some future random moment the optimal carbon tax should include an additional component on top of the conventional present discounted value of marginal global warming damages this component increases with the sensitivity of the hazard to temperature or the stock of atmospheric carbon if the hazard of a catastrophe is constant no correction is needed of the usual pigouvian tax the results are applied to a tipping point resulting from an abrupt and irreversible release of greenhouse gases from the ocean floors and surface of the earth which set in motion a positive feedback loop convex enough hazard functions cause overshooting of the carbon tax but a linear hazard function gives rise to undershooting a more convex hazard function and a high discount rate speed up adjustment

pricing uncertainty induced by climate change geophysicists examine and document the repercussions for the earth s climate induced by alternative emission scenarios and model specifications using simplified approximations they produce tractable characterizations of the associated uncertainty meanwhile economists write highly stylized damage functions to speculate about how climate change alters macroeconomic and growth opportunities how can we assess both climate and emissions impacts as well as uncertainty in the broadest sense in social decision making we provide a framework for answering this question by embracing recent decision theory and tools from asset pricing and we apply this structure with its interacting components to a revealing quantitative illustration

specialization versus diversification as a venture capital investment strategy abstract much important work has informed us of rates of return earned by venture capitalists the importance of venture capitalists to the going public process and the criteria venture capitalists use to evaluate deals this paper seeks to add to the literature by testing hypotheses based upon both the finance and strategic management literature regarding certain venture capitalist investment practices venture capitalists seek to control or manage risk driscoll 1974 macmillan siegel and subbanarasimha 1985 financing structure and investment strategy provide several means for venture capitalists to do this tools available to the venture capitalist include portfolio diversification to spread risk across different industries firms or hot cold ipo markets to minimize unsystematic or investment specific risk information sharing networking and specialization can also be used to control unsystematic risk several hypotheses are developed from these conflicting perspectives data used to test the hypotheses are derived from responses to a survey of venture capitalists three hundred surveys were mailed to venture capitalists 98 or 32 7 returned usable responses portfolio diversification is a well known means to control risk exposure by reducing unsystematic or specific risks however bygrave 1987 1988 as well as financial intermediation theorists argues that maintaining a high degree of specialization is useful for controlling risk as well as for gaining access to networks information and deal flow from other venture investors the analyses of this paper build upon bygrave s work we construct more rigorous tests to resolve the conflict between the diversification and information sharing hypotheses our hypothesis tests were usually resolved in favor of the information sharing view for example venture capitalists in the sample that were heavily involved in seed round financing were diversified across fewer numbers of firms and industries further evidence in favor of information sharing is seen in investment patterns across different financing stages diversification would imply maintaining a portfolio of investments across the different investment stages the information sharing specialization view would argue that it is best to stay focused on a single stage or several connected stages the empirical evidence from the sample once again favors the specialization perspective this research provides information of use to venture capitalists as they seek information on how best to control risk to entrepreneurs as they learn of the factors venture capitalists consider in determining their investment strategy and to academicians as such studies provide insight to general industry practice and thus help to form the basis of classroom discussion and future research endeavors

climate tipping and economic growth precautionary capital and the price of carbon the optimal reaction to a climate tipping point that becomes more imminent with global warming is to be precautionary in adjusting capital to prepare for the calamity and to price carbon to make catastrophic change less imminent the saving response can be positive or negative if the mean lag for the impact of the catastrophe is long enough the saving response will be negative because the precautionary return in the keynes ramsey rule becomes negative we also show the separate effects of the elasticity of intertemporal substitution eis and the relative risk aversion rra using duffie epstein preferences focusing on a productivity catastrophe we calibrate our model and show how sensitive the policy responses are to the degrees of eis and rra the trend rate of economic growth the hazard rate and how long it takes for the catastrophe to have its full impact

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

malthus in the light of climate change abstract to reconsider the malthusian predictions of natural limits to economic development the paper develops a multi sector growth model with exhaustible resource extraction investments in physical and knowledge capital climate change and endogenous fertility economic growth is driven by endogenous innovations which increase in the availability and productivity of research labour poor substitution of natural resources triggers sectoral change climate change is the result of polluting resource use which is like consumption and investments based on the intertemporal optimization of the households highlighting the importance of bounded resource supply and of rational extraction decisions i show that climate change is independent of population growth in steady state and there is no causal relationship between climate and population during transition to steady state the consumption per capita growth rate rises in the innovation rate and the output elasticities of labour and capital in the different sectors unlike climate policy population policy is not warranted it may be counterproductive because labour is crucial for the research sector

accounting for global warming risks resource management under event uncertainty abstract optimal management of atmospheric pollution is discussed with a special emphasis on the uncertainty concerning the occurrence of undesirable events associated with the greenhouse effect the uncertainty considered here stems from our ignorance of the exact pollution level required to trigger the event rather than from the genuinely stochastic nature of the processes involved taking atmospheric pollution level as the state variable it is found that uncertainty implies the existence of an equilibrium interval within which the emission rate of the greenhouse gases should be kept equal to the natural removal rate of these gases processes initiated outside the equilibrium interval must converge monotonically to its nearest endpoint the determination of the interval requires no knowledge of the optimal policy in contrast ignoring event occurrence risk implies a single equilibrium level attracting the optimal process from any initial level

a review of the stern review on the economics of climate change the stern review calls for immediate decisive action to stabilize greenhouse gases because the benefits of strong early action on climate change outweighs the costs the economic analysis supporting this conclusion consists mostly of two basic strands the first strand is a formal aggregative model that relies for its conclusions primari ly upon imposing a very low discount rate concerning this discount rate aspect i am skeptical of the review s formal analysis but this essay points out that we are actual ly a lot less sure about what interest rate should be used for discounting climate change than is commonly acknowledged the review s second basic strand is a more intuitive argument that it might be very important to avoid possibly large uncertain ties that are difficult to quantify concerning this uncertainty aspect i argue that it might be recast into sound analytical reasoning that might justify some of the review s conclusions the basic issue here is that spending money to slow global warming should perhaps not be conceptualized primarily as being about consump tion smoothing as much as being about how much insurance to buy to offset the small change of a ruinous catastrophe that is difficult to compensate by ordinary savings

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

optimal management with potential regime shifts we analyze how the threat of a potential future regime shift affects optimal management we use a simple general growth model to analyze four cases that involve combinations of stock collapse versus changes in system dynamics and exogenous versus endogenous probabilities of regime shift prior work in economics has focused on stock collapse with endogenous probabilities and reaches ambiguous conclusions on whether the potential for regime shift will increase or decrease intensity of resource use and level of resource stock we show that all other cases yield unambiguous results in particular with endogenous probability of regime shift that affects system dynamics the potential for regime shift causes optimal management to become precautionary in the sense of maintaining higher resource stock levels

carbon prices for the next hundred years this paper examines the socially optimal pricing of carbon emissions over time when climate change impacts are unknown potentially high consequence events the carbon price tends to increase with income but learning about impacts or their absence decouples the carbon price from income growth the price should grow faster than the economy if the past warming is not substantial enough for learning the true long run social cost it grows slower than the economy as soon as the warming generates information about events that could have arrived but have not done so a quantitative assessment shows that the price grows roughly at the rate of the economy for the next 100 years

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

optimal regulation of eutrophying lakes fjords and rivers in the presence of threshold effects eutrophication is a biological process that has an unfavorable economic impact on the economic value of the water basins it affects eutrophication depends on thresholds effects and optimal policies for the regulation of eutrophication must take this into account such optimal policies are derived in the present article by utilizing a novel technique in optimal control theory this technique facilitates a proper analysis of deterministic stock pollutants with thresholds effects a topic it is argued has been poorly understood in the literature copyright 2001 oxford university press

uncertainty and irreversibility in groundwater resource management abstract optimal exploitation of renewable groundwater resources when extraction affects the probability of occurrence of an irreversible event is studied the term irreversible signifies that the event occurrence renders the resource obsolete it is found that uncertainty concerning the event occurrence has a profound effect under certainty when the stock level below which the event occurrence has a profound effect the optimal state process converges to a unique equilibrium state under uncertainty when the event occurrence level is unknown we identify equilibrium intervals and show that optimal processes initiated elsewhere converge to a boundary of one of these intervals inside an equilibrium interval the expected loss due to the event occurrence is so high that it does not pay to extract in excess of recharge even though under certainty doing so would be beneficial

charting the territory recombination as a source of uncertainty for potential entrants in this paper we conceptualize categories as regions of a cognitive map that structure the market and guide the investment decisions of potential entrants i e of new and established organizations we advance that as a category appears altered via incumbents acts of recombination potential entrants face market specific uncertainty and are discouraged to invest in that category these negative effects of recombination on market entries are however mitigated at increasing values of category status we test our arguments in the market for electronic music the analyses of product and organizational entries in music styles between 1978 and 2011 lend support to our arguments

contagious cooperation temptation and ecosystem collapse real world observations suggest that social norms o f cooperation can be effective in overcoming social dilemmas such as the joint management of a c ommon pool resource but also that they can be subject to slow erosion and sudden collapse we show that these patterns of erosion and 15 collapse emerge endogenously in a model of a closed community harvesting a renewable natural resource in which individual agents face the tempta tion to overexploit the resource while a cooperative harvesting norm spreads through the community via interpersonal relations we analyze under what circumstances small changes in key parameters including the size of the community and the rate of technological progress trigger catastrophic transitions from 20 relatively high levels of cooperation to widespread norm violation causing the social ecological system to collapse

robustness and u s monetary policy experimentation we study how a concern for robustness modifies a policy maker s incentive to experiment a policy maker has a prior over two submodels of inflationunemployment dynamics one submodel implies an exploitable trade off the other does not bayes law gives the policy maker an incentive to experiment the policy maker fears that both submodels and his prior probability distribution over them are misspecified we compute decision rules that are robust to misspecifications of each submodel and of the prior distribution over submodels we compare robust rules to ones that cogley colacito and sargent 2007 computed assuming that the models and the prior distribution are correctly specified we explain how the policy maker s desires to protect against misspecifications of the submodels on the one hand and misspecifications of the prior over them on the other have different effects on the decision rule

temperature and growth a panel analysis of the united states this paper documents that seasonal temperatures have significant and systematic effects on the u s economy both at the aggregate level and across a wide crosssection of economic sectors this effect is particularly strong for the summer an increase of 1 f in the average summer temperature is associated with a reduction in the annual growth rate of state level output of 0 15 to 0 25 percentage points when these estimates are combined with projected increases in seasonal temperatures it is found that a reduction of u s economic growth by up to one third could occur over the next century

climate engineering under deep uncertainty abstract climate engineering and in particular solar radiation management srm is attracting increasing attention as a climate policy option however its potentially strategic nature and unforeseen side effects provide major policy and scientific challenges we study the role of srm in a two country model with the notable feature of deep uncertainty modeled as model misspecification of srm side effects we find that deep uncertainty leads to a reduction in srm deployment under both global cooperation and strategic nash behavior and that the effect is larger if countries act strategically furthermore we demonstrate that if countries have different model confidence about srm impacts then the more confident country will engage more strongly in using srm leading this country to free drive

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

pollution control in an uncertain environment abstract the effects of the threat of occurrence of environmental catastrophes on optimal pollution control are considered recent analysis of irreversible events is extended to two types of reversible events single occurrence and multiple occurrence recurrent events while it is possible that the threat of irreversible events induces more pollution we show that reversible events under quite general conditions induce more conservation less pollution the analysis is carried out via a simple method the h method to identify optimal steady states by comparing steady state policies with small variations from them for recurrent events the optimal state process must approach a unique steady state from any initial level in this case the h method characterizes the dynamic behavior of the optimal state process without actually solving for it

regulating environmental threats environmental consequences of natural resource exploitation often entail threats of future occurrences of detrimental abrupt events rather than or in addition to inflicting a damage gradually the possibility of abrupt occurrence of climate change related calamities is a case in mind the uncertainty associated with the realization of these threats and their public bad nature complicate the design of optimal economic response we derive a pigouvian hazard tax schedule that implements the socially optimal outcome the tax is based on the expected cost of the hazard generating activities and serves to reduce hazardous emissions well in advance of the catastrophic occurrence a numerical example illustrates possible effects of the proposed regulation scheme implications for climate policy are discussed

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

market liquidity hedging and crashes in the absence of significant news hedging strategies were blamed for the stock market crash of october 1987 but traditional models cannot explain how a relatively small amount of selling could cause so large a price drop the authors develop a rational expectations model in which prices play an important role in shaping expectations markets are much less liquid in their model than in traditional models discontinuities or crashes can occur even with relatively little hedging the model is consistent with theories as disparate as keynes beauty contest insights and thom s catastrophe analysis and suggests means to reduce volatility copyright 1990 by american economic association

global warming and a potential tipping point in the atlantic thermohaline circulation the role of risk aversion the risk of catastrophes is one of the greatest threats of climate change yet conventional assumptions shared by many integrated assessment models such as dice lead to the counterintuitive result that higher concern about climate change risks does not lead to stronger near term abatement efforts this paper examines whether this result still holds in a refined dice model that employs the epstein zin utility specification and that is fully coupled with a dynamic tipping point model describing the evolution of the atlantic thermohaline circulation thc risk is captured by the possibility of a future collapse of the circulation and it is nourished by fat tailed uncertainty about climate sensitivity this uncertainty is assumed to resolve in the middle of the second half of this century and the near term abatement efforts which are undertaken before that point of time can be adjusted afterwards these modelling choices allow posing the question of whether aversion to this specific tipping point risk has a significant effect on near term policy efforts the simulations however provide evidence that it has little effect for the more likely climate sensitivity values a collapse of the circulation would occur in the more distant future in this case acting after learning can prevent the catastrophe implying the remarkable insensitivity of the near term policy to risk aversion for the rather unlikely and high climate sensitivity values the expected damage costs are not great enough to justify taking very costly measures to safeguard the thc our simulations also provide some indication that risk aversion might have some effect on near term policy if inertia limiting the speed of decarbonisation is accounted for as it is highly uncertain how restrictive this kind of inertia will be future research might investigate the effects of risk aversion if additional uncertainty about inertia is considered

optimal fishery management with regime shifts an assessment of harvesting strategies this paper compares outcomes from informed and uninformed harvesting strategies for a fish stock with switching dynamics where the probability of switching is influenced by climate using data on sea surface temperature anomalies the impacts of climate on the conservation and the welfare that can be extracted from the stock are investigated results indicate that an informed management policy leads to stock biomass and resource rents that are up to 2 7 and 2 times higher respectively than under an uninformed policy also the fishery is open 54 longer under the informed policy the magnitude of these effects depends on the choice of the discount rate indicating that when the future is highly discounted gains from the informed policy dissipate