In macroeconomic models, the elasticity of substitution between clean and dirty energy inputs within the energy aggregate is a central parameter in assessing the necessary conditions for long-run green growth. Using new sectoral data in a panel of 26 countries, we formulate specifications of nested constant elasticity of substitution production functions that allow estimating this parameter for the first time. We present evidence that it significantly exceeds unity, a favorable condition for promoting green growth.

Since Griliches (1969), researchers have been intrigued by the idea that physical capital and skilled labor are more complementary than physical capital and unskilled labor. In this paper we consider the cross-country evidence for capital-skill complementarity using a time-series cross-section panel of 73 developed and less developed countries over a 25-year period. We focus on three empirical issues. First, what is the best specification of the aggregate production technology to address the capital-skill complementarity hypothesis? Second, how should we measure skilled labor? Finally, is there any cross-country evidence in support of the capital-skill complementarity hypothesis? Our main finding is that there is some empirical support for the capital-skill complementarity hypothesis in our macro panel data set.