In Medieval Europe, Bad Weather Was Especially Bad for Jews

According to Robert Warren Anderson of the University of Michigan and Noel Johnson and Mark Koyama of George Mason, inclement weather in Europe made the expulsion of Jewish communities more likely during the Middle Ages. 

Specifically, they found when looking at 785 city-level expulsions of Jews from 933 European cities between 1100 and 1800, that “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.”

Of course, the issue isn’t the weather so much as agricultural productivity levels and their impact on the regional economy — for which Jews tended to get blamed.  And as the authors note, “the persecution and expulsion of Jews in the medieval period set a powerful precedent for the persecution of other minority groups (lepers, heretics, homosexuals, and witches) that continued into the modern period.”

The relationship between weather shocks and Jewish expulsions broke down around the year 1600, which is not to say that anti-Semitism itself declined. The authors attribute this to the rise of the modern state — taking power away from the sort of feudal lords who were prone to stirring up anti-Semitism every time the harvest was bad.

But this also suggests that in places where the authority of the central state is weak, vulnerable minority groups could still be a target during times of economic distress.