Countries dependent on oil and mineral exports are often advised to diversify their economies, yet surprisingly little is known about how this can be done. This paper reviews the recent literature on diversification in resource-dependent states and suggests it has been constrained by missing and inconsistent data, and a reliance on diversification measures that are relatively uninformative for resource-rich states. It then uses an improved measure of export concentration from Papageorgiou and Spatafora to document three empirical patterns over the last half-century: the divergence between oil-producing states and non-oil states; the reconcentration of exports in most oil and mineral producing states since 1998, caused by the boom in commodity prices; and the heterogeneity of the oil producers, marked by greater diversification in Latin America and Southeast Asia, mixed performances in the Middle East, and greater concentration in Africa and the former Soviet Union. While change in the former Soviet Union was spurred by large new discoveries, the diversification failure of all oil- producing states in both North and sub-Saharan Africa is striking, and stands in contrast to the region’s non-oil producers. The paper concludes with a research agenda for deepening our understanding of this issue.

All governments either tax or subsidize the consumption of fossil fuels. These pricing policies have far-reaching consequences not only for the environment, but also for governance and economic development. In this state-of-knowledge paper, we examine previous research on fossil fuel subsidies, noting areas that are understudied in the context of determinants of price policies and causes for policy reform. We then describe new data on implicit gasoline taxes and subsidies, report global trends, and explore the relationship between oil wealth and government policies. We conclude with actionable ideas for future research projects.

Social scientists should be more deliberate in how they define and measure government efforts to reduce greenhouse gas emissions. The authors highlight key distinctions among three dimensions of climate policy: the commitments made by governments, the actions that governments take, and the outcomes they produce. In turn, the authors detail the challenges of measuring these dimensions, and discuss the tradeoffs of alternative measurement strategies, including how well they meet the accepted standards for measurement validity. The authors also identify promising avenues for further research.

Papacleovoulou and colleagues demonstrate that maternal cholestasis during pregnancy is associated with offspring adiposity and metabolic abnormalities, both in humans and in mice. This study reinforces the overwhelming evidence of the critical role of the in utero environment as a major determinant of adult health and disease.