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Spanish conquistadors of the New World.

Colonization of the Americas Caused Climatic Change


New research indicates that the death toll of the indigenous population of the Americas during and after European colonization was so high that it changed the environment around the globe and led to a worldwide cooling in temperatures that had catastrophic consequences.

In 1492, Columbus voyaged to the Caribbean and ‘discovered’ the New World. In reality the ‘New World’, as the modern Americas were known, was already home to tens of millions of people who lived in highly sophisticated societies. In the past it was assumed by many experts that the population of the Americas prior to colonization was relatively low. However, a team from the University of London have studied many new sources of demographic data and, according to the BBC, they found that up to “60 million people were living across the Americas at the end of the 15th Century (about 10% of the world's total population)”.

Landing of Columbus in the Americas 1492. (Davepape / Public Domain)

Landing of Columbus in the Americas 1492. (Davepape / Public Domain)

The Great Dying

The arrival of the Spanish Conquistadors, such as Cortez and other European conquerors, led directly to “the deaths of about 56 million people by 1600” according to the Guardian. This was the largest loss of population, in real terms in world history. The century after the arrival of the Europeans is known as the ‘Great Dying’ reports the BBC, because of this massive loss of life.

The ‘Great Dying’ is often referred to as a genocide, a deliberate attempt to destroy an entire race, because the European colonizers massacred and enslaved so many of the indigenous inhabitants. Moreover, their policies led to the downfall of great civilizations such as the Aztecs and Incas and this societal collapse led to massive loss of life. The Europeans introduced diseases such as smallpox, which resulted in devastating epidemics.

The deaths of tens of millions, and the corresponding collapse in the birth rate, was to have global environmental implications. Societies such as the Maya, Aztecs, and Inca depended on agriculture. The team from the University of London theorized that to support a population of approximately 60 million, an area the size of France had to be cultivated. This meant that there was a great deal of de-forestation and management of land by fire and this would have increased the level of carbon in the environment, causing higher global temperatures.

The Loss of Life and Climate Change

However, the deaths of millions of native Americans meant that great swathes of agricultural areas were abandoned and became grassland and forest, which are “carbon dioxide-absorbing vegetation” reports the Guardian. The reduced population also no longer had to clear land by fire for farmland and this also reduced carbon emissions. This in turn led to a significant decline in the amount of carbon in the atmosphere. Evidence of this has been found by scientists in bubbles of air found deep in the Antarctic ice.

The fall in global carbon dioxide levels is recorded in the air bubbles trapped in ice cores. (Oregon State University / CC BY-SA 2.0)

The fall in global carbon dioxide levels is recorded in the air bubbles trapped in ice cores. (Oregon State University / CC BY-SA 2.0)

The loss of so much carbon because of the ‘Great Dying’ in the Americas meant that the atmosphere began to cool. However, there were possibly other factors also contributing to the cooling, including reduced solar activity and volcanic eruptions. This cooling was dramatic, and it was apparent all over Europe by the sixteenth century. For example, the Thames in London would freeze over, and Londoners would hold ‘Frost Fairs’ on the frozen river.

Frost Fair on the River Thames near the Temple Stairs. (Szilas / Public Domain)

Frost Fair on the River Thames near the Temple Stairs. (Szilas / Public Domain)

Little Ice Age

The global cooling is known as the ‘Little Ice Age’ and it lasted from the mid-sixteenth century to the mid-seventeenth century. The fall in temperature was a disaster for many societies as they were agricultural societies, and this led to a drop-in food production. This greatly destabilized many states from Europe to Japan as death and famines became common. The ‘Little Ice Age’ was a contributory factor in the European Wars of Religion and the Fall of the Ming Dynasty which resulted in the deaths of millions. The European colonization of the New World, because it caused climatic cooling, was not only a disaster for the indigenous Americans but also for many other populations.

Agricultural Inca Terraces at Moray, Peru. (Ralf Broskvar / Adobe)

Agricultural Inca Terraces at Moray, Peru. (Ralf Broskvar / Adobe)

The study indicates that humans were having a profound impact on the climate even before the Industrial Revolution. The findings of the University of London also show that the amount of reforestation required to curb the high levels of carbon in the environment today would need to be on an unprecedented scale to prevent climate catastrophe in the future.

Top image: Spanish conquistadors of the New World. Source: Davepape / Public Domain

By Ed Whelan



Yes, 'research' with a twist. Even the natives caused some environmental destruction themselves. Even the great empires of Central America succumbed to regional climate change.

As the other commentator said, this takes the cake on stupidity.

I've read and heard some truly stupid ideas in my time, but this takes the cake. I thought the idea that a few primitive tribesmen wiped out the megafauna was over the top. How some thing like this can be taken seriously makes me doubt the sanity of so called scientists.

Ed Whelan's picture


My name is Edward Whelan and I graduated with a PhD in history in 2008. Between 2010-2012 I worked in the Limerick City Archives. I have written a book and several peer reviewed journal articles. At present I am a... Read More

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