Environment, directed technical change and economic policy

We study the effects of an economic policy in an endogenous growth general equilibrium framework where production of consumption goods requires two resource inputs: a polluting non-renewable resource and a non-polluting labour resource. The use of the former contributes to the accumulation of pollution in the atmosphere, which affects welfare. There is a specific research sector associated with each of those resources. We provide a full welfare analysis, and we describe the equilibrium paths in a decentralized economy. We go on to study the effects of three associated economic policy tools: a tax on the polluting resource, and two research subsidies. We show that the optimal environmental policy has two main effects; it delays the extraction of the resource and with it the level of polluting emissions and it reallocates research efforts, decreasing the amount put into “grey†research to the benefit of “green†research.We also show that the environmental policy is grey-biased in the short-term, and green-biased in the long-term. Finally, we compute the optimal values for these tools.