Optimal Emission Policy under the Risk of Irreversible Pollution

We consider an optimal consumption and pollution problem that has two important features. Environmental damages due to economic activities may be irreversible and the level at which the degradation becomes irreversible is unknown. Particular attention is paid to the situation where agents are relatively impatient and/or do not care a lot about the environment and/or Nature regenerates at low rate. We show that the optimal policy of the uncertain problem drives the economy in the long run toward a steady state while, when ignoring irreversibility, the economy follows a balanced growth path accompanied by a perpetual decrease in environmental quality and consumption, both asymptotically converging toward zero. Therefore, accounting for the risk of irreversibility induces more conservative decisions regarding consumption and polluting emissions. In general, however, we cannot rule out situations where the economy will optimally follow an irreversible path and consequently will also be left, in the long run, with an irreversibly degraded environment.     

Real option analysis for effects of emission permit banking on investment under abatement cost uncertainty

The present paper analyzes the investment effects of emission trading scheme (ETS) when emission permits are bankable and there is technological uncertainty with regard to the abatement cost. A real option model is employed to accommodate irreversibility of investment and cost uncertainty. In the absence of abatement cost uncertainty, a bankable ETS reduces a firm's incentive for environmental investment, because the firm can utilize the banked permits for future compliance which act as substitutes for abatement investment. However, when cost uncertainty is prevalent, investment may reduce the opportunity cost of irreversible investment under the banking system, thereby increasing a firm's investment incentive. The condition is derived under which a bankable ETS provides higher investment incentives than a non-bankable ETS does.     

Coordination and delay in global games

What is the effect of offering agents an option to delay their choices in a global coordination game? We address this question by considering a canonical binary action global game, and allowing players to delay their irreversible decisions. Those that delay have access to accurate private information at the second stage, but receive lower payoffs. We show that, as noise vanishes, as long as the benefit to taking the risky action early is greater than the benefit of taking the risky action late, the introduction of the option to delay reduces the incidence of coordination failure in equilibrium relative to the standard case where all agents must choose their actions at the same time. We outline the welfare implications of this finding, and probe the robustness of our results from a variety of angles.     

The effect of ambiguous risk, and coordination on farmers' adaptation to climate change — A framed field experiment

The risk of losses of income and productive means due to adverse weather can differ significantly among farmers sharing a productive landscape, and is of course hard to estimate, or even “guesstimate” empirically. Moreover, the costs associated with investments in reduced vulnerability to climatic events are likely to exhibit economies of scope. We explore the implications of these characteristics on farmer's decisions to adapt to climate change using a framed field experiment applied to coffee farmers in Costa Rica. As expected, we find high levels of risk aversion, but even using that as a baseline, we further find that farmers behave even more cautiously when the setting is characterized by unknown or ambiguous risk (i.e. poor or non-reliable risk information). Secondly, we find that farmers, to a large extent, coordinated their decisions to secure a lower adaptation cost, and that communication among farmers strongly facilitated coordination.     

Optimal emission-extraction policy in a world of scarcity and irreversibility

This paper extends the classical exhaustible-resource/stock-pollution model with irreversibility of pollution decay, meaning that after reaching some threshold there is no decay of the pollution stock. Within this framework, we answer the question how the potential irreversibility of pollution affects the extraction path. We investigate the conditions under which the economy will optimally adopt a reversible policy, and when it is optimal to enter the irreversible region. In the case of irreversibility it may be optimal to leave a positive amount of resource in the ground forever. As far as the optimal extraction/emission policy is concerned, several types of solutions may arise, including solutions where the economy stays at the threshold for a while. Given that different programs may satisfy the first order conditions for optimality, we further investigate when each of these is optimal. We show that it is never optimal for the economy to stay at the threshold for a while before entering the irreversible region. The optimality analysis is then illustrated by means of a calibrated example. To sum up, for any pollution level, we can identify a critical resource stock such that there exist multiple optima i.e. a reversible and an irreversible policy that yield exactly the same present value. For any resource stock below this critical value, the optimal policy is reversible whereas with large enough resources, irreversible policies outperform reversible programs.     

AN EMPIRICAL EXAMINATION OF THE HANGOVER EFFECT OF IRREVERSIBILITY ON INVESTMENT

Irreversibility does not only raise the user cost of capital and discourage new investment but also hinders disinvestment because of the hangover effect. This paper derives a theoretical model that separates the impact of conventional convex adjustment costs from the impact of irreversibility, based on which we test the hangover effect of irreversibility by using a panel of Dutch listed firms during 1985–2000. We find that the sample firms cut both the capital stock and the inventory stock facing shocks to sales and cash flow, but they cut the inventory stock by a larger magnitude than they cut the capital stock. Given that fixed investment is more irreversible than inventory investment, the result suggests that the diminished impact of irreversibility provides the firm with more flexibility in responding to uncertainty, which lends support for the hangover effect of irreversibility on investment.     

Optimal emission-extraction policy in a world of scarcity and irreversibility

This paper extends the classical exhaustible-resource/stock-pollution model with irreversibility of pollution decay, meaning that after reaching some threshold there is no decay of the pollution stock. Within this framework, we answer the question how the potential irreversibility of pollution affects the extraction path. We investigate the conditions under which the economy will optimally adopt a reversible policy, and when it is optimal to enter the irreversible region. In the case of irreversibility it may be optimal to leave a positive amount of resource in the ground forever. As far as the optimal extraction/emission policy is concerned, several types of solutions may arise, including solutions where the economy stays at the threshold for a while. Given that different programs may satisfy the first order conditions for optimality, we further investigate when each of these is optimal. We show that it is never optimal for the economy to stay at the threshold for a while before entering the irreversible region. The optimality analysis is then illustrated by means of a calibrated example. To sum up, for any pollution level, we can identify a critical resource stock such that there exist multiple optima i.e. a reversible and an irreversible policy that yield exactly the same present value. For any resource stock below this critical value, the optimal policy is reversible whereas with large enough resources, irreversible policies outperform reversible programs.     

Sensitivity of optimal programs with respect to changes in target stocks: The case of irreversible investment

Consider an aggregative model of economic growth with changing technology and tastes, in which investment is irreversible. It is shown that initial decisions in finite-horizon optimal programs are insensitive to changes in terminal stocks, provided the horizon is long enough. This generalizes Brock's result, which was proved assuming investment to be reversible. The irreversibility constraint does not allow one to follow Brock's method of proof, using the dual (Shadow Price) properties of optimal programs. An alternative method of proof is developed, using a primal approach, and exploiting dynamic programming arguments.     

Quasi-option value under strategic interactions

We consider a simple two-period model of irreversible investment under strategic interactions between two players. In this setup, we show that the quasi-option value may cause some conceptual difficulties. In case of asymmetric information, decentralized investment decisions fail to induce first-best allocations. Therefore a regulator may not be able to exercise the option to delay the decision to develop. We also show that information-induced inefficiency may arise in a game situation and that under certain assumptions inefficiency can be eliminated by sending asymmetric information to the players, even when the regulator faces informational constraints. Our model is potentially applicable to various global environmental problems.     

The effects of irreversibility on the timing and intensity of lumpy investment

This paper examines how changes in irreversibility of investment affect the timing and intensity of lumpy investment. We develop a continuous-time model wherein a firm is endowed with a perpetual option to invest in a project at any time by incurring a partially reversible investment cost at that instant. The amount of the investment cost is directly related to the intensity of investment that is endogenously chosen by the firm at the instant when the investment option is exercised. We show that higher irreversibility of investment induces the firm to raise its optimal investment trigger, thereby deferring the undertaking of the project. Furthermore, we show that changes in irreversibility of investment have no impact on the firm's optimal investment intensity due to two opposing effects that exactly offset each other. Finally, we show that higher irreversibility of investment reduces the value of the investment option and, therefore, makes the firm less valuable.     

Uncertainty, co-ordination and path dependence

Our objective is to assess whether dynamics hinder or assist co-ordination in a game with strategic complementarities. We study two dynamic aspects: different agents make decisions at different points in time; and extra information about a payoff-relevant state of nature becomes available over time. We find that the dynamic resolution of information matters most for uniqueness of equilibrium. This is demonstrated by showing that the condition for uniqueness is weaker when learning occurs. We also analyse how successfully agents co-ordinate when there is a unique equilibrium. Finally, we show that path dependence occurs: the order in which signals arrive matters, as well as the total amount of information received.     

Overcoming the coordination problem: Dynamic formation of networks

We analyze a multi-period entry game among privately informed agents who differ with respect to the number of agents who must enter in order for their own entry to be profitable. In each period agents who have not yet joined decide whether to subscribe to a network. There exists a unique equilibrium that approximates any symmetric equilibrium arbitrarily closely as the discount factor approaches one. This resolves the coordination problem. Ex-post efficiency is necessarily achieved asymptotically as the population size grows large. These results do not hold if subscribers can reverse their decisions without cost.     

Resource-grabbing by status-conscious agents

We introduce a dynamic model of resource-grabbing by status-conscious agents, i.e., agents value not only their absolute consumption levels, but also the relative status within their reference group. We explore the effect of the concern for relative consumption on the growth rate and the welfare of an economy where agents appropriate from a common property resource. Our model shows that the greater is agents' concern about their relative status, the more aggressively they tend to behave. Consequently, social welfare is lower because the growth rate of the public asset is reduced due to higher extraction rate. We also consider the effect of increased heterogeneity, and show that social welfare decreases as the distribution of status-consciousness among agents widens.     

Is investment time irreversible? Some empirical evidence for disaggregated UK manufacturing data

It has long been suggested that investment may be time irreversible, and consideration of the option value of waiting to invest has aroused renewed interest in this issue. This study tests for time irreversibility in UK investment according to disaggregation by type of investment expenditure and across manufacturing sector groupings. The test results reported indicate that the irreversibility of investment patterns varies not only from industry to industry but also according to the type of capital being purchased, with significant time irreversibility detected in gross fixed capital formation and aggregate vehicles expenditure, and industrial sector groupings comprising fuels and oil refining, engineering and vehicles, and textiles and leather. However, only in the first and last of these series is time irreversibility attributable to non-linearities in the underlying data generating process, and consistent with threshold effects which may be associated with (S,s) type models of investment dynamics.     

Networks in labor markets: Wage and employment dynamics and inequality

We present a model of labor markets that accounts for the social network through which agents hear about jobs. We show that both wages and employment are positively associated (a strong form of correlation) across time and agents. We also analyze the decisions of agents regarding staying in the labor market or dropping out. If there are costs to staying in the labor market, then networks of agents that start with a worse wage status will have higher drop-out rates and there will be a persistent differences in wages between groups according to the starting states of their networks.     

Natural disasters and electoral outcomes

Natural disasters are good examples of catastrophic events that may affect vote decisions. In this study, we analyze how the occurrence of earthquakes changes voters' behavior at municipal elections and which channels drive this change, focusing in particular on the role of media exposure. We exploit data from 13,338 municipal electoral cycles where incumbents seek reelection between 1993 and 2015 in Italy. We apply a difference-in-difference strategy with time and cities fixed effect to the probability of reelection and vote share using three different control groups: the universe of municipalities, a sub-sample of neighboring municipalities, and a sub-sample of municipalities identified by a one-to-one nearest-neighbor propensity score matching procedure. We find that the occurrence of destructive earthquakes significantly increases the incumbent mayors’ chance of being reelected and their vote share. We argue that this result is driven by the incumbent mayor advantage in offering recovery from disaster damages combined with a higher visibility on the media in the aftermath of the disaster. Thus, the mediatic relevance of earthquake occurrence may bias voters towards the incumbent.     

On the learnability of majority rule

We establish how large a sample of past decisions is required to predict future decisions of a committee with few members. The committee uses majority rule to choose between pairs of alternatives. Each member's vote is derived from a linear ordering over all the alternatives. We prove that there are cases in which an observer cannot predict precisely any decision of a committee based on its past decisions. Nonetheless, approximate prediction is possible after observing relatively few random past decisions.     

Risk taking by agents: The role of ex-ante and ex-post accountability

We study the role of accountability in situations where an agent makes risky decisions for a principal. We observe that in the absence of accountability, agents choose less risk averse investments for the principal than investors who invest for their own account. Accountability mitigates the observed decrease in risk aversion. Differences are observed between situations where agents are accountable for their decision (“ex-ante”) and where they are accountable for the outcome (“ex-post”).     

Irreversible abatement investment under cost uncertainties: tradable emission permits and emissions charges

A major concern with tradable emission permits is that stochastic permit prices may reduce a firm’s incentive to invest in abatement capital or technologies relative to other policies such as a fixed emissions charge. However, under efficient permit trading, the permit price uncertainty is caused by abatement cost uncertainties which affect investment under both permit and charge policies. We develop a rational expectations general equilibrium model of permit trading and irreversible abatement investment to show how cost uncertainties affect investment under permits. We compare the resulting investment incentive with that under charges. After controlling for the assumption that random shocks affect the abatement cost linearly, we find that firms’ investment incentive decreases in cost uncertainties, but more so under emissions charges than under permits. Therefore, tradable permits in fact may help maintain firms’ investment incentive under uncertainty.