Strategic environmental policy and the accumulation of knowledge

In dealing with a transnational pollutant-emitting duopoly welfare-maximising policy makers face two negative externalities: imperfect competition and unpriced emissions. Strategic environmental policy models show that these externalities involve a trade-off between reducing pollution and allowing for rent-seeking of the respective firm. This dilemma usually results in a suboptimal internalisation of the negative externality emerging from emissions. Indeed, the conventional model setup includes an R&D stage that enables the firms to mitigate regulation costs. But the typical one period configuration ignores that R&D expenditures create knowledge capital which is, due to its inherent cumulativeness, also effective in following periods. Our model analyses the established trade-off in a two period setting and therefore allows for an investigation of intertemporal knowledge accumulation. We find that the intertemporal effects provide an incentive for a policy maker to set a higher tax rate compared to a one-period setup which lessens the magnitude of the suboptimal internalisation of emissions. Under certain conditions even a tax rate above the Pigouvian level is possible in period 1.