As I've stated many times, it's sort of become important to me to maintain the idea that U.S. is as uniquely distinct from its pre-1500 state as possible. Partly to adhere to White's "canon", partly to keep the scenario from getting out of hand (things like Medieval Communists or the like), and partly as a sort of attraction to decolonization. For the most part this very doable with my aforementioned "100 year grace period" rule. For a good deal of places along the 40-30th parallels in the Southern Hemisphere, these places are probably irrevocably "westernized", and will have considerably more people than they did in the modern period, but overall, there would less people in the than modern city of New York, or possibly even the medieval kingdoms of Ohio of Poland.
But South America certainly raises some questions. For the Andes, much like Mexico, I've found that that dividing the countries by their urbanization almost patly matches the estimated population of the Inca Empire. This largely means having 15 to 20 million so in the western part of the continent, where much of them have maintained the Quechua language, and even their way of life. But what of the continent outside the Realm of Four Parts?
These two maps theorize five cultural divisions of South America. Well, the first has five distinct cultural divisions, the second shares "Indigenous", "European", "Mestizo" and "Plantation" but something of a "non-category" category for areas that are extremely unpopulated. It's also less concerned with keeping things contiguous.
Comparing this to respective maps of recent population densities, and biomes, calculating de-urbanized effects, and with maybe a little bit of wank, we might have an idea of Medieval South America that's turned back in time as much as possible while still recognizing the mark many people have made on it today.
For the first map, one can likely expand the "read area a little to the east, and quite possibly all the way to the coasts.As mentioned the Indigenous, sustenance-based way of life could potentially absorb the communities that might struggle with the sudden loss of industrialization. (And in places like Bolivia, was making a concentrated effort to reestablish its Pre-Columbian past). The dark green area, which the map calls the "Amazonian Basin", could also expand, mixing with the "unaffiliated" zone of the second map. This would generally be the "wilderness area", and perhaps once again be a haven for the for native people, many living like the uncontacted tribes for today.The tropical plantations would probably remain more or less as they are--slivers across the coast, distinct but so concentrated on growing and selling cash crops they would not expand, and for the most part resembling the Brazil of the middle 16th century.
This cleaves the Mestizo zone in two. We would probably have a Columbia and Venezuela that might resemble their earlier colonial counterparts or may, being at crossroads, be something of mix or extension of the Central American and Andean (and perhaps even Caribbean) societies. Then we have Brazil. A considerably large country, already divided into four zones as big as four countries in and of themselves. Outside of North America, and maybe to some extent moreso, this might have the biggest population boom of the new Middle Ages. Estimates vary, but somewhere between 3 and 11 million lived there in Pre-Columbian times. I've estimated something like 20 million people live there in the year 2900. A couple million live throughout the rainforests in grasslands in villages and communities much like they did before the first Portuguese ships. Something like a half dozen million souls probably live in the fazendas and their ports. And then there are those in the Southern Cone, in part of the same cultural sphere as Uruguay and Argentina. But then there are ten million or so people, particularly around places like Rio and Sao Paulo and Minas Gerais, where we could something truly unique, and hard to imagine, even more hard to imagine than a Medieval United States. So recent in its infrastructure, so various in its ancestry, the core of Brazil would practically be a civilization built from square one.
Then of course, there's the Southern Cone. Its temperate climate, European ancestry, and incredible soil could theoretically create a society that, perhaps out of collective homesickness, goes out of its way to recreate the middle ages in the "cosplay" manner I otherwise try to avoid. Or perhaps its "Gaucho" tradition would assert itself. Or maybe being on the other side of the world would similarly build something new and alien. I'm somewhat impartial to a world that somewhat resembles the late Roman Empire myself.
