[konjin]

A civilization stops scientific activity when you kill its scientists and burn its libraries. Who would have thought?

How much science would get done in the US if everyone in the 50 largest cities is killed or enslaved and the cities are razed?

[inglor_cz]

Well, it is not as if other regions of the world, including Europe, did not have their own massive disasters.

Vikings, Mongol attacks, Turkish attacks, the 30 Year War...

An interesting question why was Baghdad so unique that its loss led to disaster. Could it be that the rest of the Muslim world was, by this point in time, not very interested in science?

European science survived such events probably because of its polycentricity. There was no single point of failure.

[konjin]

Because Egypt was conquered by the Mamluks and Andalusia by the Spanish at the same time. There was no area under Muslim control that was not ruled by barbarians whose idea of hygiene was washing their posterior every time they crossed a river.

The Mongol invasion was a unique event in Eurasian history. They make every other invasion and conquest seem tame by comparison. If you have a choice of facing Macedon, Rome, Napoleon, Nazi Germany, the USSR or the Mongols never choose the Mongols.

It was the first and only time a single power could have destroyed all other civilizations and came very close to it. To the point where they managed to destroy both the Polish, Hungarian and Romanian crusader armies within days of each other, with minimum casualties and would have continued depopulating Europe to the English Channel if the Khan had not died and the majority of the army returned home for a civil war.

The reason Europeans aren't riding horses fighting a rear-guard action against the Aztec conquistadors is because the Mongol court liked silks and perfumes enough to not raze every city they conquered.