Before Christopher Columbus set foot on American soil the Amazon was a pristine wilderness. Populated only by small numbers of indigenous tribes, it was largely untouched by human hand.

Or so we thought. Until now.

Earlier this year, scientists published new research that shows Pre-Columbian Amazonia was home to millions more people than previously understood. The researchers used satellite imaging to find ancient geoglyphs – earthworks they believe were used for ceremonies – in parts of the Brazilian state of Mato Grosso that had never been explored by archaeologists. In doing so, they uncovered evidence of hundreds of urban conurbations, deep inside the rainforest.

By analysing charcoal remains and excavated pottery they found a 1,800 km stretch of southern Amazonia was continuously occupied from 1250 until 1500 by people living in fortified villages. Computer modelling their findings, they then estimated that there would have been between 1,000 and 1,500 enclosed villages, across 400,000 km² of Southern Amazonia. This number of villages could have supported a population between half a million and a million people.

As the area studied was far from major rivers and only takes up 7% of the entire Amazon region, the ramifications of these findings are huge in terms of what the overall population must have been at the time. It now seems highly likely the Amazon rainforest was densely populated in the past, with its occupants running into millions.

Many experts believe that the only possible explanation for how such numbers of people could have existed in the rainforest was the ‘terra preta’ – the potent black soils bio-engineered by the local people using charcoal, which still cover large areas of Amazonia to this day. The standard soils of most tropical rainforests, including in the Amazon, are typically poor, due to a process called ‘nutrient cycling’, which means most of the nutrients are to be found in the vegetation and not in the ground. The indigenous people somehow worked out that by adding charcoal – along with bones and manure – they could create these prized, dark, nutrient-rich soils and then use them to grow crops. It is hard to imagine how the lost cities of the Amazon would have been possible without this ‘super dirt’. It’s the most obvious explanation for how large-scale agricultural production was feasible.  

Interestingly, these new findings about Amazonia’s population back up reports of large, interconnected villages made by a few Europeans in the sixteenth century – which were later dismissed as exaggerations or even outright fantasy. For example, Spanish conquistador Francisco de Orellana was the first European to navigate the entire length of the Amazon in 1541. He wrote of highly populated villages and farms along much of its banks. He also described massive cities visible in the distance. But when explorers and missionaries returned to the places he’d described centuries later, they found nothing but thick vegetation, making them doubt the veracity of his tales. We now know he told the truth.

But where did all these millions of people go? Sadly, the likelihood is that they were wiped out by European diseases or massacred by conquistadors. The few that survived were forced to abandon their villages, towns and cities – and, as a result, their agricultural heritage. We can only assume they must have fled deep inside the rainforest and returned to a nomadic, hunter-gatherer lifestyle or perished. The only visible signs that their civilisation ever existed is the terra preta, a precious commodity which we can learn much from today.

From 1st of September, we’re going to be selling our very own terra preta. Inspired by the ancient Amazonians, Sacred Earth’s Biochar Soil Booster contains the eco-friendly charcoal known as biochar – along with a unique recipe of comfrey tea, seaweed and biodynamic compost preparations. It will be available from our online shop, costing £9.99 for 3kg.