Grubler and Pachauri (1) criticize our first order assumption of no change in inequality over time at the regional level, suggesting—after Kuznets—that a country's inequality first grows and then falls with economic development. Unfortunately, empirical evidence for the Kuznets curve hypothesis is extremely weak and has been disputed in several recent papers (3, 4). Only the World Bank, to our knowledge, has published projections of income distributions (5), and these are very uncertain. Thus, we took a conservative approach in our work. ...