Comment by gorgmah
8 hours ago
I was wondering the same things : I often heard that the relative civilizational collapse that happened in europe during the middle ages was correlated with lower overall temperatures, e.g. what you see here [1] or there [2]. In the second one, the most recent projections (in red), show that there were a lot of very cold years (down to -0.6 degrees relative to normal) during those times. Later on, starting in the 1200s, there was the Little ice age, where temperatures fell to -0.9 relative to normal (I don't know how they defined normal). The peak, when almost all years were at -0.6 or below on that scale, caused the "General Crisis of the seventeenth century" where people from the Goth/scandinavian regions also had huge famines [3].
So my guess would be that there were several very cold years in a row, which caused famines, and the populations understood that their best survival chance was to migrate south, where they had to compete with the roman empire for land.
[1] https://fr.wikipedia.org/wiki/Fichier:2000_Year_Temperature_... [2] https://fr.wikipedia.org/wiki/Fichier:2000_Year_Temperature_... [3] https://en.wikipedia.org/wiki/Great_Famine_of_1695%E2%80%931...
For many decades, climate events have been viewed as one driver of cultural events during the Age of Migrations: somewhere on the Asian steppe, decline in quality pasturage successively causes one people to pressure another people to their west, and eventually the avalanche rolls into Europe.
It has saddened me to see this viewpoint associated in the American cultural wars with one party's "enemy camp", where discussion of climate as a problem is automatically associated with all kinds of unrelated policy positions. People are unaware this historical explanation was posited by hoary old (and largely long-dead) twentieth-century men who had no dog in the contemporary political divide.