Management of an annual fishery in the presence of ecological stress: The case of shrimp and hypoxia

The emergence of ecosystem-based management suggests that traditional fisheries management and protection of environmental quality are increasingly interrelated. Fishery managers, however, have limited control over most sources of marine and estuarine pollution and at best can only adapt to environmental conditions. We develop a bioeconomic model of optimal harvest of an annual species that is subject to an environmental disturbance. We parameterize the model to analyze the effect of hypoxia (low dissolved oxygen) on the optimal harvest path of brown shrimp, a commercially important species that is fished in hypoxic waters in the Gulf of Mexico and in estuaries in the southeastern United States. We find that hypoxia alters the qualitative pattern of optimal harvest and shifts the season opening earlier in the year; more severe hypoxia leads to even earlier season openings. Failure to adapt to hypoxia leads to greater losses when the effects of hypoxia are more severe. However, rent gains from adapting fishery management to hypoxia are relatively small compared to rent losses from the hypoxia effect itself. This suggests that it is critical for other regulatory agencies to control estuarine pollution, and fishery managers need to generate value from the fishery resources through other means such as rationalization.     

Accumulative pollution, “clean technology,” and policy design

This paper addresses the optimal long-term management of an accumulative but assimilable pollutant through economic incentive policies that restrict more damaging production processes and induce more benign alternatives. Using a simple general equilibrium approach, we consider the possibility that the assimilative capacity of the environment is eventually exhausted by pollution accumulation. In this case, there is a nonconvexity in the problem that gives rise to multiple potential optima; environmental quality may be preserved or completely degraded in the long term. We characterize the circumstances under which phasing out dirty production is consistent with an intertemporally optimizing path and we discuss the design of price-based and quantity-based policies for supporting an optimal solution with the nonconvexity.     

Tradeoffs between costly capacity investment and risk of regime shift

There is mounting evidence that increasing natural resource exploitation (e.g., fossil fuel extraction and consumption) could trigger irreversible dramatic ecological events like global warming. While capacity investment costs and the possibility to produce at full capacity are two factors that critically affect the exploitation rate, little is known about their effect on management. I generalize standard models of pollution control under the threat of dramatic regime shifts to investigate how optimal management changes with both factors. My analysis reveals that accounting for such factors gives rise to investment and emissions policies that challenge conventional wisdom. For instance, I find that under reasonable conditions, an exogenous threat of a doomsday event induces a cautious management strategy. Using parameters estimated from climatic data, my analysis shows that raising the discount rate can induce lower emissions, highlighting the complex interplay between the threat and both factors.     

Optimal Investment in Clean Production Capacity

For the mitigation of long-term pollution threats, one must consider that both the process of environmental degradation and the switchover to new and cleaner technologies are dynamic. We develop a model of a uniform good that can be produced by either a polluting technology or a clean one; the latter is more expensive and requires investment in capacity. We derive the socially optimal pollution stock accumulation and creation of nonpolluting production capacity, weighing the tradeoffs among consumption, investment and djustment costs, and environmental damages. We consider the effects of changes in the pollution decay rate, the capacity depreciation rate, and the initial state of the environment on both the steady state and the transition period. The optimal transition path looks quite different with a clean or dirty initial environment. With the former, investment is slow and the price of pollution may overshoot the long-run optimum before converging. With the latter, capacity may overshoot.     

The environmental Kuznets curve when the environment exhibits hysteresis

The relevance and implications of the environmental Kuznets hypothesis are examined in the presence of stock effects and non-linearities associated with pollution generation. Stock effects lead to hysteresis and irreversibilities in environmental quality that are overlooked when emphasis is placed on the flow effects of pollutants only. It is demonstrated here that an optimal growth plan in the presence of stock effects shifts the focus away from prescribing economic growth as a panacea for environmental ills. Implications for currently industrializing economies are discussed.     

A dynamic general equilibrium model of pollution abatement under learning by doing

In 2013, Beladi et al. constructed a dynamic general equilibrium model of pollution, and characterized a steady-state equilibrium. In this paper, we extend Beladi et al.’s model to an even more general model in which the pollution abatement costs under learning by doing are taken into account. In our model, the instantaneous abatement costs depend on both the rate of abatement and the experience of using a technology. Our objective is to apply optimal control theory to investigate the dynamic general equilibrium model of pollution abatement, and derive the steady-state equilibrium properties and optimal levels of emission permits and pollution treatment.     

Precaution under mixed uncertainty: Implications for environmental management

A model of pollution control subject to two types of uncertainty is presented. First, the natural decay of the pollution stock follows stochastic dynamics that drives a diffusion pollution process (“stochastic uncertainty”). Moreover, the damage coefficient which determines the amount of damage corresponding to each pollution stock can undergo an abrupt increase at some uncertain future time (“event uncertainty”). The model admits an explicit and simple dynamic characterization of the optimal emission rule and the ensuing pollution process. When only one type of uncertainty is permitted (by setting either the variance of the stochastic process or the hazard rate for the damage increase to zero) it acts to promote the intuitive response of precaution. However, allowing the two types to interact gives rise to a non-monotonic behavior, whereby increasing the stochastic variance first enhances, then diminishes the response to the hazard. The results confirm and expand recent findings based on discrete-time formulations.     

Environmental impact of household activity in Spain

The objective of this paper is to analyse the environmental impacts of the Spanish economy by way of water and atmospheric pollution on the basis of a Spanish Accounting Matrix for 1999. Only households were taken as an exogenous account. The pollution measures are estimated for seven categories of pollution: three atmospheric pollutants (CO₂, NO_x and SO_x) and four indicators for water (waste water, nitrogen, metals and biological oxygen demand (BOD)). The environmental data base was obtained from the Spanish Statistical Institute.The analysis reveals that pollution in Spain is closely linked to food production, energy, extractive industries and paper manufacturing. We show that services, taken as a whole, are major polluters, though this is due to the volume of household expenditure they represent rather than their pollution potential as such. We also show that the Spanish economy avoids a great deal of pollution by importing inputs, which pollute where they are produced. Finally, the study also provides per capita pollution values for the aforementioned seven pollutants.     

Environmental regulations and innovation activity in UK manufacturing industries

We examine the relationship between environmental regulations and innovation, using data from UK manufacturing industry during 2000-2006. We estimate a dynamic model of innovation behaviour, and explicitly account for the likely endogeneity of our measure of the stringency of environmental regulations (pollution abatement costs). Our results indicate that while on the one hand environmental R&D and investment in environmental capital are stimulated by greater pollution abatement pressures, on the other hand there is not a positive impact of environmental regulation on total R&D or total capital accumulation. We find some evidence that this is because more stringent environmental regulations directly lower the optimal expenditure on non-environmental innovations. In addition, we find that environmental R&D may crowd out non-environmental R&D, although there is no evidence that environmental capital crowds out non-environmental capital.     

Growth effects of environmental policy when pollution affects health

In this paper, we develop a R&D-based growth model with a pollution externality and a health production sector. We study how health-impairing pollution affects long term growth, and the effect of an emissions' reduction policy (tax). We show that a tighter environmental tax has positive effects on growth via two channels. On the one hand, it improves workers' health and, thereby, productivity; on the other hand, it induces a reallocation of resources towards R&D and, thereby, higher research intensity. The size of the growth effect of a tighter environmental tax, and the level of the optimal environmental tax, are both positively correlated with the weight individuals place on health relative to consumption. As for welfare, a tighter environmental tax brings about utility gains in the long run and, potentially, also in the short run.     

Intertemporal transfers of emission quotas in climate policies

We are interested in situations in which governments are committed to some pollution abatement constraint which does not match the society's most preferred level of pollution, like in the current climate change policies undergone on behalf of the Kyoto protocol. We develop an overlapping generations model with capital and pollution in which the individuals care about the environmental quality. We show that slightly improving the intertemporal flexibility of the emission quotas by authorizing two-period backward and forward transfers allows to decentralize the whole optimal growth path at competitive equilibrium.     

The optimal initial allocation of pollution permits: a relative performance approach

The initial allocation of pollution permits is an important aspect of emissions trading schemes. We generalize the analysis of Böhringer and Lange (2005, Eur Econ Rev 49(8): 2041–2055) to initial allocation mechanisms that are based on inter-firm relative performance comparisons (including grandfathering and auctions, as well as novel mechanisms). We show that using firms’ historical output for allocating permits is never optimal in a dynamic permit market setting, while using firms’ historical emissions is optimal only in closed trading systems and only for a narrow class of allocation mechanisms. Instead, it is possible to achieve social optimality by allocating permits based only on an external factor, which is independent of output and emissions. We then outline sufficient conditions for a socially optimal relative performance mechanism.     

Co-ordinated environmental regulation: controlling non-point nitrate pollution while maintaining river flows

Environmental policy often addresses multiple targets, yet much economic analysis of pollution control is based on a single-target objective. In this paper, we present an analysis of policies to control non-point source nitrate pollution in the presence of minimum river flow restrictions. A non-linear bio-physical economic optimisation model of an intensively cultivated Scottish agricultural catchment was constructed. The presence of minimum river flow controls in the catchment was found to reduce nitrogen pollution. However, by themselves, river flow controls were found not to be a cost effective means to reduce non-point pollution. We quantify the improved social welfare from coordinating the environmental regulation of river flows and pollution, and determine the conditions under which such coordination is beneficial. The paper also investigates whether the benefits of such coordination can be sustained under wetter (winter) weather conditions implied by current climate change predictions.     

Free trade and the burden of domestic policy

Abstract. Consider a small economy facing accession to a exogenously defined trade agreement. Before accession, the government controls trade and pollution policy. After accession, it retains control over pollution policy, but must allow free trade in all goods. This is a choice many governments face while joining trade agreements today. They decide whether greater market access to other members is more valuable than control over trade policy. I ask two questions. All else being equal what happens to environmental policy after accession? Second, what affects the choice of accession and how does this choice impact aggregate welfare? I show that a loss in control over trade policy alters the political incentives determining environmental policy. Before accession, producers can transfer a portion of their burden of environmental regulation to consumers through price increases. After accession the same regulation is borne entirely by producers. Owing to the change in burden, there exist plausible conditions under which the adoption of free trade can lead to more stringent environmental regulation, a reduction in the preferential treatment of special interest groups, and an increase in aggregate welfare.     

The effect of climate change on optimal wetlands and waterfowl management in Western Canada

Warmer temperatures and a decrease in precipitation in the 21st century could severely deplete wetlands in the prairie pothole region of western Canada. In this study, we employ linear regression analysis to determine the casual effect of climate change on wetlands in this region, with temperature, precipitation and the standardized precipitation index (SPI) used to predict the effect of potential climate change on wetlands. We then use a waterfowl-wetlands bioeconomic model to solve for socially optimal levels of duck harvests and wetlands retention under current climate conditions and various climate change scenarios. The model maximizes benefits to hunters plus the amenity values of ducks to non hunters and the non-market ecosystem benefits of wetlands. Results indicate that climate change could decrease wetlands by between 7 and 47%, and that the optimal number of wetlands to retain could decrease by as much as 38% from the baseline climate.     

Renewable resource management with environmental prediction: the importance of structural specification

Environmental variability can substantially influence renewable resource growth, and as the ability to forecast environmental conditions improves, opportunities for adaptive management emerge. Using a stochastic stock‐recruitment model, Costello, et al. ( 2001 ) show the optimal management response to a prediction of favourable growth conditions is to reduce current harvests. We find this result may be reversed when environmental variability and stock are substitutes in growth, a possibility that has been ignored by resource economists. As an example, we analyze the South Carolina white shrimp fishery, finding the optimal response to a prediction of favourable overwinter conditions is to increase fall harvests.     

Optimal pollution control in a mixed oligopoly with research spillovers

We study optimal pollution abatement under a mixed oligopoly when firms engage in emissions‐reducing research and development (R&D) with imperfect appropriation. The regulator uses a tax to curb emissions. Results show that in a mixed oligopoly, the public firm has positive emissions reduction in equilibrium; however, emissions reductions of the private firm could be positive or zero. Under certain conditions, the optimal pollution tax is positive; otherwise, the tax reverts to a subsidy. Comparing mixed and private duopolies, privatisation leads to reductions in R&D and output, but to an increase in overall emissions, so privatisation tends to make the environment worse.     

Are short‐term effects of pollution important for growth and optimal fiscal policy?

We study optimal fiscal policy in a stock‐flow model of the environment within an endogenous growth framework, where some pollutants have a lasting impact on environmental quality which is restored through abatement expenditure, while others dissipate and hence, have a short‐term effect on the environment. All pollutants, however, affect the productivity of a public good negatively. Given that short‐term pollution, although it dissipates, is irreversible in this sense, a government cannot ignore its negative effects since this type of pollution lowers the productivity of all inputs. We find that a larger negative effect of short‐term pollutants as well as a higher congestion effect of private capital leads to corrective fiscal policies with higher optimal income tax and abatement expenditure rates, which have favorable growth consequences. Interestingly, we find that the rate of short‐term pollution does not affect optimal fiscal policy while that of the long‐term pollution does.     

Climate policy in Western Europe and avoided costs of air pollution control

Abatement of CO₂ emissions will be accompanied by reduced air pollutant emissions such as particulate matter (PM), SO₂, and NO_x. This, in turn, will reduce the need for end of pipe (EOP) pollution control technologies to meet future air quality targets. This dynamic could put more stringent air quality goals within reach, and increase the political feasibility of climate policy. This paper presents a CGE model that has been modified to include the emissions and EOP abatement of PM, SO₂, and NO_x from stationary sources in the EU-17. Emissions of pollutants are modeled as fixed-factor complementary inputs to their associated source. Abatement in each sector is modeled as a substitution between the pollutants and discrete abatement technologies, each of which is sector-specific and characterized by a marginal abatement cost and technical capacity constraint. Scenarios are run to 2020, to assess the costs and co-benefits of simultaneous air quality and climate policies. We find that under the Kyoto Protocol in 2010, the welfare cost of pollution control is reduced by 16% compared to the baseline, effectively offsetting the cost of CO₂ abatement by 15%. The co-benefit results depend heavily on policy choices, and their magnitude relative to total costs is likely to decline as greenhouse targets become more ambitious. In our scenarios, pollution control cost savings range from 1.3 to 20% in 2020, yielding a climate cost offset range of 0.2 to 3.9%. The CO₂ credit imports allowed by the EU via the Clean Development Mechanism (CDM) offer a total savings of $9.7bn in 2020, but only need to be compensated by an additional $0.3–0.4bn in domestic pollution control from stationary sources.     

Disutility of pollution and endogenous growth

Endogenous growth is generally built on a positive externality hypothesis which is the opposite of a negative externality caused by pollution. We study a linear technology with simple assumption: an aggregate capital stock which represents a learning by doing effect and a pollution flow proportional to production. In this framework, we analyse the precise effects on growth of the disutility of pollution and its interaction with the utility of consumption in an economy without abatement technology. The decentralized equilibrium always leads to unlimited growth, but optimal growth is often limited (the negative effect of pollution dominating the positive effect of learning by doing). In this case, the optimal policy which leads the decentralized economy to follow the optimal growth path is to tax capital; in contrast with the optimal subsidy policy in an economy without pollution. When an abatement technology is introduced, the optimal solution can lead the economy to unlimited growth, whatever the form of the utility function.