If environmental quality positively affects the productivity of labor in R&D and pollution is caused by the use of a non-renewable resource, it is socially optimal to postpone extraction and to intertemporally adjust R&D effort.

Environmental policy affects the distribution of market shares if intermediate goods are differentiated in pollution intensity. When innovations are environmental friendly, a tax on emissions skews demand towards new goods, which are the most productive. In this case along a balanced growth path...