When European Colonization of the Americas ended 10% of the lives on earth ( 56 million people died)

It was caused by the fact that there hadn't been pandemics here in north, south or central America likely because pandemics and plagues are often caused by rats getting into grain people are storing in bigger cities around the world.

Europeans had been having periodic plagues and pandemics since about 3000 BC throughout the Mediterranean area in Ancient Greek, Roman and Egyptian times. There were plagues that wiped out as many as 95% of people in any one city where a plague hit.

But, as the 5% that didn't die reproduced these children and descendants had immunities that the 95% that died didn't have.

So, when these descendants led by Columbus came to the New World of North, South and Central America this wiped out 90% of the 60 million people in North, South and Central America.

This then allowed colonization because well over 50 million people died within a few years of contact with White people from Europe. Here is a word button or link that describes this in more detail:

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• European colonization of the Americas killed 10 percent of world population and caused global cooling