The Timing of Environmental Policy: A Note on the Role of Product Differentiation

We examine the role that product differentiation can play in the design of environmental policy under full commitment and no commitment on the part of the environmental regulator. We consider a setting with two firms selling a differentiated product which generates pollution through emissions. Firms can reduce their emissions by undertaking abatement activities while an environmental regulator taxes emissions. The main results are: (1) When products are highly differentiated, the optimal time-consistent (no commitment) tax is always lower than the optimal pre-commitment tax. As the degree of product differentiation decreases, for relatively efficient abatement technology and high damages, the time-consistent emission tax exceeds the optimal pre-commitment one. (2) Abatement when product differentiation is extensive is higher under the time-consistent regime unless the abatement technology is extremely efficient. The same ranking applies to social welfare. However, as products become more and more similar, these results are (partially) reversed and pre-commitment could lead to both higher levels of abatement and welfare.     

Managerial firms’ profitability,unions, and environmental taxes

This article examines how determining an optimal environmental tax in a Cournot duopoly with unionized labour markets and managerial firms departing from the strict profit-maximization. It is shown that firm-specific monopoly unions that set wages (1) reduce both the environmental tax and environmental damage and (2) counterintuitively, increase firms’ profitability when the abatement technology is not too “efficient”, and the public evaluation of environmental quality is sufficiently high. Within this framework, the work also develops the endogenous game played by firms that must choose between sales delegation (SD) and profit-maximization. Results show that the SD contract always emerges as the unique, deadlock sub-game perfect Nash equilibrium, thereby solving the (prisoner's) dilemma emerging in the related existing literature assuming a competitive labour market.     

Public Goods and Tax Competition in a Two‐Sided Market

A rather neglected issue in the tax competition literature is the dependence of equilibrium outcomes on the presence of firms and shoppers (two‐sided markets). Making use of a model of vertical and horizontal differentiation, within which jurisdictions compete by providing public goods and levying taxes in order to attract firms and shoppers, this paper characterizes the noncooperative equilibrium. It also evaluates the welfare implications for the jurisdictions of a popular policy of tax coordination: The imposition of a minimum tax. It is shown that the interaction of the two markets affects the intensity of tax competition and the degree of optimal vertical differentiation chosen by the competing jurisdictions. Though the noncooperative equilibrium is, as it is typically the case, inefficient such inefficiency is mitigated by the strength of the interaction in the two markets. A minimum tax policy is shown to be effective when the strength of the interaction is weak and ineffective when it is strong.     

Regulating a Polluting Oligopoly: Emission Tax or Voluntary Agreement?

This paper compares, in a polluting oligopoly, an emission tax and a form of environmental policy called voluntary agreement (VA). Here there are two ways of reducing pollution: output contraction and end‐of‐pipe abatement. Given the imperfect competition, firms’ reaction to the tax is sub‐optimal. They reduce output excessively in order to raise the price and do not abate enough. The VA is a take‐it‐or‐leave‐it contract on abatement effort, offered to the firms with the threat of a tax. It has a limited effect on output and always allows higher abatement than the tax. We find that this kind of VA may be more efficient than the tax in a concentrated industry, when pollution is not too harmful and when the abatement technology is rather efficient and cheap.     

Multinational taxation and international emissions trading

Many studies have shown that the activities of multinational corporations are quite sensitive to differences in income tax rates across countries. In this paper I explore the interaction between multinational taxation and abatement activities under an international emissions permit trading scheme. Four types of plans are considered: (1) a single domestic permit system with international offsets; (2) separate national permit systems without trade; (3) separate national permit systems with limited offsets; and (4) an international permit trading system. For each plan, I model the incentives for the multinational firm to choose abatement activities at home and abroad and to transfer emissions credits between parent and subsidiary. Limits on trading across countries restrict efficiency gains from abatement, as is well known. But if available offset opportunities are limited to actual abatement activities, those activities are also more susceptible to distortions from incentives to shift taxable income. Transfer-pricing rules can limit but not always eliminate these distortions. In a system of unlimited international trading, abatement is efficiently allocated across countries, but tax shifting can still be achieved through intra-firm transfer pricing. From the basis of efficiency for both environmental and tax policies, the best design is an international permit trading system with transparent, enforceable transfer-pricing rules.     

The perverse effect of environmental regulation on emissions: The role of product-mix changes

We study the effect of environmental regulation (taxation) on emissions when the only available abatement method consists of product-mix changes. Firms choose to produce one or both varieties of a product—a pollution-intensive (dirty) and a non-pollution-intensive (green)—and compete in a differentiated Cournot duopoly. We characterize the equilibrium market structure as a function of the tax rate and show that increases in the tax can promote product-mix changes that lead to a jump in emissions for some tax range, an effect we call the perverse effect of taxation. Our work emphasizes the key role horizontal product differentiation in this process and shows that the perverse effect does not require the presence of vertical product differentiation. Further, the perverse effect of taxation is especially strong in the presence of incomplete regulation, that is, when only one of the markets is subject to taxation.     

Regulating a Polluting Firm Under Asymmetric Information

This paper reinterprets the Laffont-Tirole model of regulation under asymmetric information to cover the case of pollution control. The asymmetry of information concerns the firm's cost of lowering its pollution. The regulator has three objectives: Ensuring an efficient abatement level, generating 'green taxes' and securing the survival of the firm. We show that when optimal abatement is important relative to tax generation, the regulator cannot use the policy of offering the firm a set of linear tax schemes from which to choose. By contrast, this policy is optimal in the Laffont-Tirole model under certain not very restrictive assumptions. We proceed to establish a simple rule for when to shut-down inefficient types. In an example with specific functional forms, we derive the optimal tax function both analytically and graphically. We show the effect on the optimal tax system of a change in a technological parameter.     

Pollution Abatement Investment When Environmental Regulation Is Uncertain

In a dynamic model of a risk-neutral competitive firm that can lower its pollution emissions per unit of output by building up abatement capital stock, we examine the effect of a higher pollution tax rate on abatement investment both under full certainty and when the timing or the size of the tax increase is uncertain. We show that a higher pollution tax encourages abatement investment if it does not exceed a certain threshold rate. However, akin to the Diamond-Mirrlees tax anomaly, it is possible that a higher pollution tax rate results in more pollution. The magnitude uncertainty discourages abatement investment, but at the time of the actual tax increase the abatement investment path may shift either upward or downward. On the other hand, when the timing is uncertain, the abatement investment path always jumps upward, thus suggesting that the effect of magnitude uncertainty on the optimal investment path may be more pronounced than that of timing uncertainty. Further, we show that the ad hoc practice of raising the discount rate to account for the uncertainty leads to underinvestment in abatement capital. We show how the size of this underinvestment bias varies with the future tax increase. Finally, we show that a credible threat to accelerate the tax increase can induce more abatement investment.     

Joint Management of Emission Abatement and Technological Innovation for Stock Externalities

We investigate how emission abatement and technological innovation provide different solutions to reduce pollutant emissions. In the case of a stock externality emission abatement leads to a smooth and continuous adjustment of emissions. Conversely, technological innovation has to be interpreted as an option on a less polluted environment and can justify the use of a pollution threshold above which it is optimal to start a research and development programme for a less polluting technology. It is shown that technological innovation interferes with the traditional emission abatement approach. The optimal abatement level is logically lowered once the less polluting technology is available; nevertheless a temporary increase in emissions is optimal during the research and development period. The usual Pigouvian tax system proves to remain an efficient corrective instrument. A numerical application to the Greenhouse effect is provided.     

Environmental Funds,Public Abatement,and Welfare

This paper addresses some features of environmental funds that the government uses to finance public abatement with pollution tax revenue or tariff revenue. I find that when the pollution tax rate and the tariff rate are jointly chosen optimally, then the optimal pollution tax rate is higher than the Pigouvian tax rate under public abatement financed by tariff revenue, and lower when public abatement is financed by pollution tax revenue. Furthermore, I show that the optimal tariff rate is positive regardless of which tax revenue is used to finance public abatement. These results are relevant for countries where the government seeks revenues earmarked for the financing of environmental funds.     

Emission taxes for genuine altruistic firms

This article develops a theoretical model that explores firms' abatement choices. The main results are: First, in a market comprised of a not sufficiently large number of heterogeneous firms always there exists a subset of firms that are willing to undertake abatement activities, if their marginal altruistic cost of emissions is positive. Second, a low emission tax induces abatement when a firm is egoistic or if its altruistic cost of emissions has a concave structure. In contrast, if the firms’ altruistic cost of emissions has a convex structure, then intermediate emission taxes are required. Third, the effect of firms’ altruistic cost of emissions on the emission tax that induce the socially optimum abatement is also conditional on the genuine altruistic preferences and finally, the social planner has an incentive to impose a Pigouvian emission tax when firms are profit maximizers. Otherwise, a lower tax suffices.     

Optimal environmental taxation and enforcement policy

We study the optimal environmental taxation and enforcement policy when (i) the regulator does not know the firms’ abatement costs, (ii) penalties for tax evasion are limited, and (iii) monitoring of pollution is costly. We show that the threat of being audited alter the usual firms’ incentives to over-estimate their abatement costs. In particular, depending on the firms’ abatement costs, the optimal policy may involve over or under-deterrence compared to the full information outcome. We then investigate the properties of a pollution standard. We show that this policy comes close to an environmental tax once the economic incentives of the accompanying enforcement policy are considered.     

Emission Taxes and Product Differentiation in the Presence of Foreign Firms

Industries characterized by differentiated products are important contributors of greenhouse gases and currently subject to market‐based policies such as emission taxes. In the context of developing countries, fears about foreign investment leaving the country are often used as an argument not to address industry emissions through emission taxes. This paper develops a Cournot model with product differentiation in the presence of abatement efforts where host and foreign firms are subject to an emission tax. The analysis indicates that abatement efforts and differences in pollution intensity coefficients across firms may play a significant role in the characterization of optimal policy. The analysis also suggests that the government may opt to encourage foreign, less pollution‐intensive firms via higher taxation. Additionally, this paper examines how an optimal emission tax may be adjusted as products become more differentiated; industry emissions may fall/rise as a result of more differentiated products. One important contribution of this paper is that it emphasizes the role of abatement efforts, product differentiation, and differences in pollution intensity coefficients across firms in the characterization of the optimal emission tax.     

Weitzman Revisited: Emission Standards Versus Taxes with Uncertain Abatement Costs and Market Power of Polluting Firms

Studies dealing with the optimal choice of pollution control instruments under uncertainty have invariably taken it for granted that regulated firms face perfectly competitive markets. By introducing the product market into the stochastic framework of Weitzman (Rev Econ Stud 41:477–491, 1974), this paper shows for the case of a polluting symmetric Cournot oligopoly that Weitzman’s policy rule for choosing emission standards versus taxes with uncertain abatement costs is biased in the presence of market power. Since the oligopolists take into account their influence on the market price, their total abatement effort, including the restriction of output, is less vulnerable to miscalculations of the tax rate compared to price-taking firms. Consequently, the comparative advantage of instruments is shifted in favour of taxes. In a further step, the provided policy recommendations are generalised by abolishing the assumption that firms are symmetric.     

Location decisions of a polluting firm and the time consistency of environmental policy

This paper considers location decisions of a monopolist, who faces a tax on its emissions in the home country, under ex post that is, time consistent, and ex ante, that is precommitment, environmental policies. We show that the monopolist will relocate more often under ex post optimal emission taxes. A government which cannot commit to an ex ante emission tax and sets its tax ex post after abatement effort has been chosen, is unable to affect the monopolist’s location decision, because it cannot commit to strategically reduce its tax level in the first stage. Domestic welfare is often higher under ex post emission taxes whenever the monopolist relocates under both policy regimes. Otherwise, welfare is higher under government commitment to an ex ante emission tax level. Thus, government commitment to a policy is not always welfare improving.     

Incentives to Diffuse Advanced Abatement Technology Under the Formation of International Environmental Agreements

We analyse the incentives for polluting firms to diffuse and adopt advanced abatement technology in a framework in which governments negotiate an international environmental agreement. These incentives crucially depend on whether the underlying environmental policy instrument is an emission tax or an emission quota. The results for the international setting fundamentally differ from those for the national setting that have been elaborated upon in the earlier literature. In particular, equilibrium diffusion and adoption of advanced abatement technology are not necessarily optimal under the tax regime and may be even lower than those under the quota regime.     

Market power,private information,and the optimal scale of pollution permit markets with application to North Carolina's Neuse River

We extend the analysis of optimal scale in pollution permit markets by allowing for both market power and private information. We characterize the total costs (abatement costs and damages) under market power and private information and compare them to total costs under competition. It is possible for both market power and private information to lead to lower total costs than competition, but generally the differences between the three market structures will be small. We also conduct an optimal scale analysis of nitrogen pollution from waste water treatment plants (WWTP) into North Carolina's Neuse River System. An economic model of damages and abatement costs is integrated with a hydro-ecological model of nitrogen flow through the Neuse. We determine the optimal number of trading zones and allocate the WWTP into these zones. Under the most likely regulatory scenario, we find cost savings of 1.55 million dollars per year under the optimal market design relative to the typical 303(d) regulation in which the WWTP are not allowed to trade.     

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.     

Dynamic optimal control of pollution abatement under emissions permit banking

In a recent work, Dragone et al. (2010) modeled an optimal control model of pollution abatement, and investigated the adoption of a tax levied on the firm's instantaneous contribution to the accumulation of pollution. In this paper, we extend the work of Dragone et al. (2010) by providing a dynamic optimal control model of pollution abatement with emissions permits banking, where the firm is allowed to purchase, sell and bank emissions permits given a finite planning horizon of length. Our objective is to find the optimal levels of the production, the pollution abatement investment and the quantity of emissions permits bought or sold in continuous time through the use of optimal control theory. We illustrate the results with a numerical example.     

Managing the quality of a resource with stock and flow controls

We consider a class of problems, which we call “SFQ” problems, in which both stocks and flows can be controlled to promote the quality of a valued resource, such as environmental quality or public infrastructure. Under the optimal policy, periodic restoration of the stock of quality complements positive but variable abatement of the flow of damages. When deterioration is more rapid or highly variable, or when abatement is more expensive relative to restoration, the optimal policy relies relatively more on restoration.When deterioration is due to private firms or individuals, a flow tax equal to the present value of marginal damages provides efficient incentives for abatement. This tax rises at first as quality worsens, but eventually falls as restoration nears. The revenues raised by such a tax approximates the cost of restoration, with the two quantities converging as the variance of flows goes to zero.We discuss the implications of the SFQ model for a range of real-world problems in the environmental arena, and for the management of public infrastructure. But the lessons are general, and we briefly discuss how they apply to private stocks of physical and human capital.