While Europe was in the early days of the Renaissance, there were empires in America with more than 60 million people. But the first European contact in 1492 brought diseases in America that devastated the native population and resulted in the collapse of agriculture in America was so significant that it could even calm the global climate.
The number of people living in North, Central and South America, when Columbus arrives, is a matter that researchers are trying to answer for decades. Unlike Europe and China, records of the size of indigenous societies in America before 1492 are not preserved. In order to reconstruct the population numbers, the researchers rely on the first reports from European eyewitnesses and, in the record after colonial rule, were paid payments known as "encomiendas". This system of taxation was established only after the European epidemics devastated America, so it tells us nothing about the size of pre-colonial populations.
Early accounts of European colonists are likely to overestimate the large settlements and population to advertise the treasures of newly discovered countries to their feudal sponsors in Europe. However, by rejecting these claims and focusing on colonial records, at the beginning of the 20th century, extremely low estimates of the population were calculated, which calculated the population once the disease was destroyed.
On the other hand, liberal assumptions about, for example, the percentage of indigenous people who were supposed to pay more lenient or the rates at which people died, led to extraordinarily high estimates.
Our new study clarifies the size of the populations in front of Columbia and their impact on their environment. By combining all published estimates from populations throughout America, we found a probable indigenous population of 60 million in 1492. By comparison, the European population at that time was 70-88 m wide in less than half of the area.
The large pre-Columbus population was maintained through agriculture – it has extensive archaeological evidence of agriculture with pavement and burns, terraced fields, large earthen embankments and home gardens.
Knowing how much agricultural land is needed to maintain a person, the population can be translated from an area that is known to be under human land use. We found that 62 million hectares of land, or about 10% of the land area of America, were farmed or under other humane use when Columbus arrived. For comparison, in Europe 23% and in China 20% of the land was used by people at that time.
This changed in decades after the Europeans first set foot on the island of Hispaniola in 1497 – now Haiti and the Dominican Republic – and the mainland in 1517. Europeans brought smallpox, measles, influenza and bubonic plague across the Atlantic, with disastrous consequences for indigenous populations.
Our best estimate of data-based data is a figure of 56 million deaths by the early 1600's – 90% of the pre-Columbian indigenous population and about 10% of the world's population at that time. This makes "Great Dying" the greatest human death event proportional to the global population, placing the second in absolute terms only in World War II, which killed 80 million people – 3% of the world's population at the time.
The 90% mortality rate in post-contact America is remarkable and outweighs similar outbreaks, including Black Death in Europe – resulting in a loss of 30% in Europe. One explanation is that multiple outbreaks of epidemics have affected autochthonous immune systems that have evolved isolately from the Eurasian and African populations for 13,000 years.
The Indians at that time were never in contact with the pathogenic microorganisms brought by the colonists, creating the so-called. "epidemics of virgin soil". People who did not die from smallpox died of the next wave of influenza. Those who survived that succumbed to measles. War, hunger, and colonial atrocities made the rest of the Great Dying.
This human tragedy meant that there were simply not enough workers to manage fields and forests. Without human intervention, previously managed landscapes returned to their natural states, thus absorbing carbon from the atmosphere. The extent of this retrospective of natural habitats was so great that it removed enough CO₂ to cool the planet.
Lower temperatures have triggered carbon-backbone feedback, which eliminates even more CO₂ from the atmosphere – as less CO2 is released from the soil. This explains the collapse of CO₂ in 1610 in Antarctic ice cores, resolving the enigma why the whole planet is cooling briefly in the 1600s. During this period, severe winters and cold summers cause hunger and rebellion from Europe to Japan.
The modern world began with a catastrophe of almost unimaginable proportions. However, it is America's first time to be connected with the rest of the world, which marks the beginning of a new era.
We now know more about the volume of pre-European American populations and the Great Dying, who have erased so many of them. Human activities at that time caused a drop in the atmospheric CO₂ that hung the planet long before human civilization was concerned with the idea of climate change.
However, such a dramatic event will not greatly contribute to easing the rate of modern global warming. An unprecedented afforestation event in America led to a reduction of 5 pieces per million CO₂ from the atmosphere – only three-year emissions of fossil fuels.