Research shows temperature changes caused persecution of European Jews

Economic historians at George Mason University have discovered a connection between sudden adverse weather changes and the persecution of Jews and other religious minorities during the pre-industrial era.

Between 1100 and 1800 in Europe, periods of unusually cold weather that resulted in economic hardship were responsible for the expulsion or persecution of thousands of Jews, the research shows.

Economists Noel Johnson and Mark Koyama in Mason’s College of Humanities and Social Sciences, with co-author Robert Warren Anderson from the University of Michigan–Dearborn, studied 1,366 instances of persecution of Jews across 936 cities.

They discovered that the incidence of persecution, including murder, of Jews were more likely to occur following unusually cold growing seasons. These “temperature shocks” often led to crop failures and other economic disruptions.

Jews, members of the only religion allowed by law to loan money at interest, were often treated as scapegoats, said Johnson. While Jews were making monopolist profits by lending to farmers and business people at interest, it was the Christian rulers who collected theses profits.

“After a serious crop failure, rulers could redistribute money to the masses to buck up their political power by taking it from the Jews,” Johnson said. “Or they could let the crowd take it themselves. This is often what happened.”

For example, in 1614 Frankfurt, Germany, many guild craftsmen and traders were in debt to Jewish lenders following a series of cold snap-induced crop failures. Antagonism between the local patricians and the business people led to rebellion—and the plundering of the Jewish ghetto and the expulsion of Jews from the city.

The Frankfurt Jews were eventually permitted to return. Not so for the residents of 100 Jewish communities in Bavaria and Alsace in 1338. Drastic temperature deviations beginning in 1336 led to economically motivated social uprisings and massacres.

The rulers who gave Jews monopoly rights to lend at interest where, in effect, “reinforcing anti-Semitism,” said Johnson. “This, in turn, made it very easy for the rulers to say to the Jews, ‘If you don’t give me the money you are making then I’m going to unleash the crowd on you.’”

Koyama said resource-shortage persecutions have not been eradicated in modern times. In fact, it’s happening now.

“Minorities—immigrants—have been targeted in the United Kingdom post-Brexit,” he said. “I don't think developed countries are immune to these effects, though obviously not on the same scale as one observes in medieval Europe or 19th-century Russia.”