This is a fascinating pair of films from National Geographic that look at the Columbian Exchange, by examining the ecological state of the Old World and the New World before Columbus sailed to the Americas, and again what the impact was after they had made contact.
Although unacknowledged, the films draws upon the ground-breaking work of Jared Diamond in examining these phenomena, who in his Guns, Germs and Steel, showed how the development of high-yield agriculture and animal husbandry had formed the basis for technology on the one hand and given a natural immunity to many diseases migrating from animals on the other.
It does spend some time discussing the civilisations, cultures and ecology in the Americas before the arrival of the Europeans, but it spends an equal amount of time discussing the same subjects in their European context, and it is interesting to see the differences.
Even in the Middle Ages the Europeans had already ravaged their continent, emptying the rivers, destroying the forests, and giving rise to exterminating plagues, nearly all of which arose through their animal husbandry.
Owing to overcrowding and depletion of resources they were quite ready to go and find a New World to rape and pillage, and when the deluded Columbus, who believed he was going to India, arrived he had not only horses and armour, but also the diseases with him.
You could almost call it biological warfare, except the perpetrators didn’t know what they were doing any more than their compatriots, who brought back syphilis, did. Even in the Americas some civilisations had already collapsed because of climate change, and over usage of raw materials, but it was nothing to the devastation caused by disease, which many scholars estimate wiped out 90% of the population in under a century.
Not only were native Americans affected, but also local flora and fauna were overrun by the introduction of new plants and animals, which in some cases displaced local varieties, and changed the continent as much as the humans who brought them.