Cees Withagen

Pollution control and the Ramsey problem

Pollution is an inevitable by-product of production and is only gradually dissolved by the environment. It can be reduced by producing less and by cleaning up the environment, but neither occur when they are left to the market. Cleaning activities and the optimal emission charges increase with the stock of pollutants. When one allows for pollution of the environment in the classical Ramsey problem, the capital stock is less than in the market outcome and a fortiori less than under the golden rule. The analysis distinguishes between stock and flow externalities arising from pollution. An increase in impatience can lead to more capital accumulation, even though this leaves less room for current consumption.

The Hartwick Rule: Myths and Facts

We shed light on the Hartwick rule for capital accumulation and resource depletion by providing semantic clarifications and investigating the implications and relevance of this rule. We extend earlier results by establishing that the Hartwick rule does not indicate sustainability and does not require substitutability between man-made and naturalcapital. We use a new class of simple counterexamples (i) to obtain the novel finding that a negative value of net investments need not entail that utility is unsustainable, and (ii) to point out deficiencies in the literature.

Dynamics of China's regional development and pollution: an investigation into the Environmental Kuznets Curve

This paper addresses the existence of an Environmental Kuznets Curve for China, using a sampleof thirty regions and covering the period 1982-1997. The types of pollution included in the studyare wastewater, waste gas and solid waste. We consider the development of the sources ofpollution in a pooled cross-section analysis considering the pollution in absolute levels, in percapita terms and relative to real GDP. At intermediate levels of GDP per capita, the increase of solidand gas emissions tends to decelerate, but accelerates again at high levels of GDP per capita.Water pollution decreases with per capita GDP.

Growth, Renewables, and the Optimal Carbon Tax

Optimal climate policy is investigated in a Ramsey growth model of the global economy with exhaustible oil reserves, an infinitely elastic supply of renewables, stock‐dependent oil extraction costs, and convex climate damages. Four regimes can occur, depending on the initial social cost of oil being larger or smaller than that of renewables and depending on the initial oil stock being large or small. We also offer some policy simulations for the first and second regime, which illustrate that with a lower discount rate more oil is left in situ and renewables are phased in more quickly. We identify the conditions under which the optimal carbon tax rises or decreases. Subsidizing renewables (without a carbon tax) induces more oil to be left in situ and a quicker phasing in of renewables, but oil is depleted more rapidly initially. The net effect on global warming is ambiguous.

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.

Innovation and Environmental Stringency: The Case of Sulfur Dioxide Abatement

A weak version of the Porter hypothesis claims that strict environmental policy provides positive innovation incentives, hence triggering improved competitiveness and securing environmental quality. In a comparative way, this paper empirically tests this hypothesis across countries by linking environmental stringency to innovation proxied by patents in the field of SO2 abatement over the period 1970-2000. Three different models of environmental stringency are examined. Two of these models do not reveal a positive significant effect on innovation as a result of increased stringency. In the theoretically preferred model, however, a positive relationship between environmental stringency and innovation is obtained.

Global Warming and the Green Paradox: A review of adverse effects of climate policies

This article examines the possible adverse effects of well-intended climate policies, an outcome known as the Green Paradox. A weak Green Paradox arises if the announcement of a future carbon tax or a sufficiently fast rising carbon tax encourages fossil fuel owners to extract reserves more aggressively, thus exacerbating global warming. We argue that such policies may also encourage more fossil fuel to be locked in the crust of the earth, which can offset the adverse effects of the weak Green Paradox. We show that a subsidy on clean renewables may have similar weak Green Paradox effects. Green welfare (the converse of environmental damages) declines (i.e., the strong Green Paradox) if the beneficial climate effects of locking up more fossil fuel do not outweigh the short-run weak Green Paradox effects. Neither the weak nor the strong Green Paradox occurs for the first-best Pigouvian carbon tax. We also discuss dirty backstops, spatial carbon leakage, and green innovation.

Environmental Policy, Population Dynamics and Agglomeration

Abstract We present and discuss a simple model of international trade in agricultural and manufactured commodities. Production of the latter takes places under monopolistic competition, and causes pollution. We incorporate mobility of skilled labor, the input in the manufacturing sector. One of the main findings is that pollution and environmental policy tend to countervail clustering that would occur in their absence.

The Alberta dilemma: optimal sharing of a water resource by an agricultural and an oil sector

The purpose of this paper is to characterize the optimal time paths of production and water usage by an agricultural and an oil sector that have to share a limited water resource. We show that for any given water stock, if the oil stock is sufficiently large, it will become optimal to have a phase during which the agricultural sector is inactive. This may mean having an initial phase during which the two sectors are active, then a phase during which the water is reserved for the oil sector and the agricultural sector is inactive, followed by a phase during which both sectors are active again. The agricultural sector will always be active in the end as the oil stock is depleted and the demand for water from the oil sector decreases. In the case where agriculture is not constrained by the given natural inflow of water once there is no more oil, we show that oil extraction will always end with a phase during which oil production follows a pure Hotelling path, with the implicit price of oil net of extraction cost growing at the rate of interest. If the natural inflow of water does constitute a constraint for agriculture, then oil production never follows a pure Hotelling path, because its full marginal cost must always reflect not only the imputed rent on the finite oil stock, but also the positive opportunity cost of water.

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.