in Rome it simply wasn’t possible to imagine a world that wasn’t dominated by Rome …
But The Empire was dominated by Byzantium aka Constantinople for a thouand years after Constantine the Great moved the capital from Rome in the 5th century. It was overrun by the Ottoman Turks around 1450ish and continued as The Ottoman Empire until the end of World War 1. So for most of The Empire’s existence ‘the world’ (i.e. what the Empire controlled,) was not dominated by Rome but by Constantinople / Byzantium, but the remote provinces were under constant threat from The Persian Empire, the Turks, Slavs, Ostergoths, Germans, while the Vandals, hun and Visigoths seemed to wander around Rome itself at will. And to the people of the great civilisations in India, China and south east Asia, Rome was some distant, insignificant city state populated by savages.
So the comparison of the fall of Rome and climate change works quite well because the official narratives we get from governments, the education system and mainstream media differ considerably from what we find when we do some real research.
It’s unfortunate the original author had such serious health problems, but I simply cannot see what that has to do with climate change. But then we really know so little for certain. Maybe the last ice age (now that was serious climate change,) occurred because Ug son of Gronk was a martyr to his piles.