The weather — its effects on the environment, behavior, sports, and society — has long been of interest to Freakonomics. Now a new working paper from Warren Anderson, Noel D. Johnson, and Mark Koyama explores the effects of cold growing seasons on discrimination against Jewish communities between 1100 and 1800:
What factors caused the persecution of minorities in medieval and early modern Europe? We build a model that predicts that minority communities were more likely to be expropriated in the wake of negative income shocks. We then use panel data consisting of 785 city-level expulsions of Jews from 933 European cities between 1100 and 1800 to test the implications of the model. We use the variation in city-level temperature to test whether expulsions were associated with colder growing seasons. We find that a one standard deviation decrease in average growing season temperature in the fifteenth and sixteenth centuries was associated with a one to two percentage point increase in the likelihood that a Jewish community would be expelled. Drawing on our model and on additional historical evidence we argue that the rise of state capacity was one reason why this relationship between negative income shocks and expulsions weakened after 1600.