From John Ray's shorter notes

January 19, 2019

Long lost cities in the Amazon were once home to millions of people

The introduction to a recent article in New Scientist below sets the scene for what is now known about the prehistory of Amazonia.  I have recently read quite a few of the scientific studies of the subject in the hope of finding out WHY civilization largely vanished from Amazonia in quite recent times.  It seems that at least some parts of Amazonia were as developed as the Incas in Peru and the Aztecs in Mexico.  So it seems important to understand what happened to the Amazonian civilization. 

It might be better to refer to it as the Arawak civilization as the Northern Amazon seems to be the origin of a group of Arawak languages that are now widely spread in Northern South America and the Caribbean.  The original Arawaks clearly had a lot of influence one way or another

And even the archaeologists may have underestimated the extent of Arawak civilization.  "Black" soil is widely found in Amazonia and black soil is an artifact of human cultivation. The natural soils of Amazonia are rather poor and infertile but that can be remedied by burning any combustible material to hand.  That leaves a residue of charcoal (carbon!) which makes the soil much more fertile and suitable for the cultivation of crops.  So we are dealing with a pretty big phenomenon in studying the human history of Amazonia

The obvious reason for the collapse of pre-Columbian civilization in Amazonia (Arawakia?) is the white man's diseases.  The conquistadores in Mexico and Peru had to wait only a little bit before disease decimated their native opponents, making conquest by the few over the many a possibility and a reality.

And we saw that sort of thing vividly in the progress through what we now know as the Southern United States by Spanish explorer Hernando de Soto.  De Soto pushed North from Mexico into more Northern lands not for conquest but in search of gold.  And wherever he went he found flourishing native tribes.  Those who slightly later followed in his footsteps, however, found an almost depopulated landscape.  The diseases De Soto and his men carried with them had completely wiped out the former flourishing tribes.

So on the DeSoto precedent, disease is clearly a sufficient explanation of the population loss and subsequent loss of civilization in Amazonia.  But is it the whole explanation? The people of Peru and Mexico were not wiped out to anything like that extent and adapted their ways to the Spanish influence so that they substantially survived the catastrophe that had overtaken them.

Which is where we come to climate change. It appears that for much of the latter Holocene the Amazon had much less rainfall and existed in Savannah-like conditions. But Savannah can grow crops and it seems that the natives did just that. As the earth continued to rebound from the last ice age, however, rainfall increased. And rainfall fertilizes everything, including "weeds" ("Weeds" are just unwanted plants) and fungi. And the native agriculture may have been struggling with that problem at the time the Spaniards arrived. So the Spaniards and their diseases were the last straw for a struggling Amazonian civilization

It is all speculation at the present stage of our knowledge but it seems that the Greenies may be getting it partly right in their occasional squawks about the Amazon.  Global warming has in fact been bad for civilization in the Amazon in the past.  But there is nothing in rainforest that daunts modern civilization and its machines.

And the usual Greenie claim that Amazonia is pristine forest and, as such, should not be touched by human hands, is completely uninformed, as we expect from Greenies. "Don't bother me with the facts" seems to be their motto. There may in fact be no original forest in Amazonia

Amazonia has in fact already been heavily modified by human hands, with its fertility in particular being greatly increased by human intervention.

THE Amazon rainforest is so vast that it boggles the imagination. A person could enter at its eastern edge, walk 3000 kilometres directly west and still not come out from under the vast canopy.

This haven for about 10 per cent of the world’s species has long been regarded as wild and pristine, barely touched by humanity, offering a glimpse of the world as it was before humans spread to every continent and made a mess of things. It is painted in sharp contrast to the logged forests of Europe and the US.

But it now seems this idea is completely wrong. Far from being untouched, we are coming to realise that the landscape and ecosystem of the Amazon has been shaped by humanity for thousands of years. Long before the arrival of Europeans in the Americas, the Amazon was inhabited, and not just by a handful of isolated tribes. A society of millions of people lived there, building vast earthworks and cultivating multitudes of plants and fish.

We don’t fully understand why this flourishing society disappeared centuries ago, but their way of life could give us crucial clues to how humans and the rainforest could coexist and thrive together – even as Brazil’s new government threatens to destroy it.

Some of the first Europeans to explore the Amazon in the 1500s reported cities, roads and cultivated fields. The Dominican friar Gaspar de Carvajal chronicled an expedition in the early 1540s, in which he claimed to have seen sprawling towns and large monuments. But later visitors found no such thing.


Go to John Ray's Main academic menu
Go to Menu of longer writings
Go to John Ray's basic home page
Go to John Ray's pictorial Home Page
Go to Selected pictures from John Ray's blogs