We develop an endogenous growth model in which long-run growth is driven by three engines: private abatement R&D, expanding-variety R&D, and capital accumulation. We show that an environmental tax activates private abatement by directing researchers from the variety R&D sector to the abatement R&D sector, which helps the economy avoid the environmental disaster. Our results also show that the effect of the environmental tax on long-run growth is uncertain, depending mainly on the relative productivity between the two R&D sectors. If the abatement R&D sector is sufficiently productive, increasing the environmental tax will enhance the balanced output growth rate and social welfare.

In this paper, we examine the effects of international capital mobility on innovation, growth, and optimal growth policies in a small open economy with R&D‐driven growth. Households can borrow funds from an imperfect international capital market to finance their investment in R&D firms. We show that the economy can reach a higher growth rate if international capital is more mobile. This result is consistent with recent empirical findings. Moreover, we show that the common growth‐enhancing policies, such as patent protection and the R&D subsidies, have an additional negative welfare effect when households can access the international capital market. Accordingly, the optimal patent protection and R&D subsidy should be smaller when the degree of international capital mobility is higher.

No abstract