This paper explores the consequences and origins of contemporary differences in well-being across ethnic groups within countries. The authors show that ethnic inequality is strongly inversely related to per capita income, and that differences in geographic endowments across ethnic homelands explain a sizable portion of contemporary ethnic inequality. This deeply rooted inequality in geographic attributes across ethnic regions is also negatively related to comparative development.

This paper studies empirically technology diffusion across countries and over time, finding significant evidence that technology diffuses slower to locations that are farther away from adoption leaders. The authors document the significant role that geography plays in determining technology diffusion across countries.

Hot countries tend to be poorer. This column uses the cross-century, cross-country variation in climatic temperatures to estimate the effects of historic temperature upon current incomes. The negative relationship between current temperature and income appears due to temperature variations in the 18th and 19th centuries. That suggests that the consequences of climate change may be felt for a very long time.

African nations with ‘bad’ terrain suffered less from the slave trade. More than a century after the slave trade ended, the protective benefits of ruggedness still outweigh its contemporary economic disadvantages when it comes to GDP per capita.