Romerrikets nedturer - og lite regn

I en artikkel i uken The Economist med tittelen: "The rise and the rainfall of the Roman empire" skriver de om hvordan noen forskere har studert på sammenhengen mellom politisk ustabilitet og variasjoner i regnvær, i Romerriket. De skriver:

"In a new paper published in Economics Letters, Cornelius Christian of Brock University and Liam Elbourne of St Francis Xavier University identify a strong association between rainfall patterns and the duration in power of Roman emperors. The academics hypothesise that lower precipitation reduced crop yields, leading to food shortages and eventually starvation for soldiers stationed at the empire’s frontiers. As a result, troops were more likely to stage mutinies and assassinate their emperor."

Forskerne mener at det for omkring 1500 år siden var en nokså klar sammenheng mellom tørke og politisk uro, for eksempel når det gjaldt hyppigheten på drap på romerske keisere. I alt 25 keisere ble myrdet, omtrent 20 prosent av totalen, men disse var på ingen måte jevnt fordelt over perioden. Spesielt i den gordiske perioden var det mye uro:

"The Gordian dynasty from 235 AD to 285 AD was particularly tumultuous: 14 of the 26 emperors who ruled were assassinated during this period. Of course hungry troops were not the only cause of the demise of emperors. This period was also marked by plague, invasions and economic depression."