I've read the draft[^1] of the article, and I'm not convinced. The hypothesis is simple : less rain in Germania caused more Germanic raids on the Empire Empire,

I've read the draft[^1] of the article, and I'm not convinced. The hypothesis is simple : less rain in Germania caused more Germanic raids on the Empire Empire, which caused political instability, which caused imperators' assassinations. When I look of some of these assassinations, I doubt the Germanic provinces had any impact on them. The Roman Senate got rid of Caligula for internal reasons. Claudius was (probably) poisoned to make place for Nero. The historical drought of 69-70 that Tacitus mentioned did not cause any assassination. The year of the 4 emperors was not following any kind of Germanic instability. Later on, many rebellions came from the East. In the later centuries, the eastern emperors had little to to with rain in western Europe. Reading the article, the correlation doesn't seem very strong. To my untrained eyes, it looks like the years 220-300 are the main factor of correlation. It was a period of drought Gaule and Germania, and political instability in Rome, but I'm not convinced of the causality. It's always seducing to discover a causal logic in historical events. Theories that can explain history have a high power of seduction, so I am even more cautious. [^1]: https://brocku.ca/repec/pdf/1703.pdf https://brocku.ca/repec/pdf/1703.pdf