There was no fire from Heaven moment called "The Fall of Rome".
There were some rough spots of barbarian invasions and the like, but no definite "fall". It was a slow decline spread out over centuries, giving way to the Middle Ages.
Rome had a Deep State.
Yes, plenty of challenges, not the least of which was the capture of the North African bread-basket that supported the city's welfare state not by Climate Change but by the Vandals. Climate change certainly turned that into the arid area we know today but nowhere near quickly enough to explain the events of the 5th century.
The empire was too big and too tired to continue in its present state, which was recognized in the early 4th century and was the reason that Constantine was trotted off to build Constantinople on the bones of Byzantium. Which, as others on the thread as well as Gibbon pointed out, lasted another millennium. What "fell" in 1453 was the same as "fell" in 476: nothing at all like what was before.