We examine the impact of an optimal emissions tax on research and development of emission reducing green technology (E-R&D) in the presence of R&D spillovers. We show that the size and effectiveness of the optimal emissions tax depends on the type of the R&D spillover: input or output spillover....

We study a dynamic model with two competing durable goods; one dirty, the other clean. Due to network effects a consumer who adopts the dirty good today will increase the incentive future consumers have to adopt the dirty good. Thus, a consumer who chooses the dirty good, in a sense causes more...