LAST year over 102,000 people died in nearly 50 armed conflicts across the world, according to the Peace Research Institute Oslo, a think-tank. Much of this violence is caused by tensions between ethnic groups—two-thirds of civil wars have been fought along ethnic lines since 1946. Yet historians differ over whether cultural differences or economic pressures best explain how tensions explode into violence.
A new study* by Robert Warren Anderson, Noel Johnson and Mark Koyama suggests that, historically, economic shocks were more strongly associated with outbreaks of violence directed against Jews than scholars had previously thought. The authors collected data for 1,366 anti-Semitic events involving forced emigration or murderous pogroms in 936 European cities between 1100 and 1800. This was then compared with historical temperature data from a variety of sources, including tree rings, Arctic ice cores and contemporary descriptions of the weather.
Cold spells hit medieval agriculture hard: a one-degree Celsius fall in temperatures reduced the growing season by up to four weeks. Lower yields caused widespread economic pain: up to 57% of people relied on farming for work in medieval England, for instance. The authors find that a fall in average temperatures of only a third of a degree increased the probability of a pogrom or expulsion by 50% over the next five years. They argue that violence against Jews was not simply caused by religiously-motivated anti-Semitism: “The Jews were convenient scapegoats for social and economic ills.”
Read more: https://www.economist.com/news/finance-and-economics/21725593-historically-there-were-more-anti-semitic-attacks-when-crops-failed-link