A 2019 scientific study by the University College London, UK, and published in the Quaternary Science Reviews, found that European colonization and genocide of the indigenous people of the Americas at the end of the fifteenth century cooled the planet, the authors concluded.
The new research, funded by the UK Natural Environment Research Council, suggests that this led to a regrowth of forests and a reduction in carbon dioxide (CO2) levels, which in turn contributed to the Earth’s cooling.
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The scientists report that as the population plummeted, land was abandoned and farming ceased causing natural vegetation to grow back.
Scientists believe that the changes to land use led to a lowering of CO2 levels sufficient enough that the concentration of the gas in the atmosphere eventually fell by 7-10ppm.
The process of genocide began in 1492 when Christopher Columbus "discovered" a new world that they thought was India. So they were lost, not discoverers, but once they returned to Iberia, his tales of a new world piqued the interest of Spanish royalty, who funded his journey again. Columbus was arrested and sent back to Spain in chains for mismanagement of Hispaniola. King Ferdinand pardoned him in 1504 after he barely survived a voyage to Spain from Haiti and then paid for his fourth voyage. He died in Spain in 1506.
The Native American empires collapsed to foreign diseases, killing native people who had no previous exposure to them, and the people enslaved and massacred for colonizers to steal their land and other riches.
The researchers estimate that over the 100 years after European arrival, the indigenous population of the Americas dropped from 60 million (ten percent of the global population) to only 6 million due to waves of epidemics, warfare, and famine.
The land used by native Americans began a massive reforestation, causing more CO2 to be absorbed and sunk in the soil, cooling the Earth.
"There is a lot of talk around 'negative emissions' approaches and using tree-planting to take CO₂ out of the atmosphere to mitigate climate change, and what we see from this study is the scale of what's required, because the Great Dying resulted in an area the size of France being reforested and that gave us only a few ppm. This is useful; it shows us what reforestation can do. But at the same, that kind of reduction is worth perhaps just two years of fossil fuel emissions at the present rate."The new research, funded by the UK Natural Environment Research Council, suggests that this led to a regrowth of forests and a reduction in carbon dioxide (CO2) levels, which in turn contributed to the Earth’s cooling.
“The Great Dying of the Indigenous Peoples of the Americas led to the abandonment of enough cleared land that the resulting terrestrial carbon uptake had a detectable impact on both atmospheric CO2 and global surface air temperatures,” said lead study author PhD candidate Alexander Koch (UCL Geography).
The ‘Great Dying’ was triggered by the arrival of Europeans and the introduction of new pathogens to the continent. Together, with warfare and slavery, there was an epidemic of diseases such as smallpox, measles, influenza and cholera.
The scientists calculated how much land previously cultivated by indigenous civilisations would have fallen into disuse, and what the impact would be if this ground was then repossessed by forest and savannah.
The area is in the order of 56 million hectares, close in size to a country like modern France.
This scale of regrowth is figured to have drawn down sufficient CO₂ that the concentration of the gas in the atmosphere eventually fell by 7-10ppm (that is 7-10 molecules of CO₂ in every one million molecules in the air).
"To put that in the modern context - we basically burn (fossil fuels) and produce about 3ppm per year. So, we're talking a large amount of carbon that's being sucked out of the atmosphere," explained co-author Prof Mark Maslin.
"There is a marked cooling around that time (1500s/1600s) which is called the Little Ice Age, and what's interesting is that we can see natural processes giving a little bit of cooling, but actually to get the full cooling - double the natural processes - you have to have this genocide-generated drop in CO₂."
Today, the carbon cycle has changed. We are getting hotter, drier, and wetter, setting life on a path to extinction.
Trillions of Tons of Carbon Are Missing From Climate Models
According to a new study by the Chinese Academy of Sciences and Australia’s Commonwealth Scientific and Industrial Research Organization, the top two meters of soil beneath our feet currently hold roughly 2.3 trillion tonnes of inorganic carbon—five times more than all of the terrestrial plants on Earth combined.
Scientists arrived at this number by analyzing 200,000 soil samples from around the world, and found that concentrations of inorganic carbon were higher in arid and semi-arid landscapes where water is less likely to carry away these carbonates. While countries like Australia are particularly filled with inorganic carbon—the continent is the fifth largest repository, according to the study—its also found in wetter regions along rivers and around lakes and coastal areas. So, these carbon-locking soils impact the entire world. The results of the study were published last week in the journal Science.
“This huge pool of carbon is affected by changes in the environment, especially soil acidification. Acids dissolve calcium carbonate, meaning the carbon dissolves in water or is released as carbon dioxide gas,” the researchers wrote in an article for The Conversation. “This huge pool of carbon is affected by changes in the environment, especially soil acidification. Acids dissolve calcium carbonate, meaning the carbon dissolves in water or is released as carbon dioxide gas.”
Inorganic carbon—mostly in the form of solid carbonate minerals like limestone, marble, or chalk—is different from organic carbon like plant litter, bacteria, and animal waste. While the latter has been gaining global attention, inorganic carbon has been largely ignored as a significant tool in the Earth’s process of regulating CO2 in the atmosphere and a potential source of the climate change-inducing gas.
The study estimates that some 23 billion tonnes of inorganic carbon could be released over the next 30 years, with little knowledge on how this will impact the planet’s land, water, and atmosphere. By comparison, the airline industry emits roughly 1 billion tonnes of CO2 every year, so this inorganic carbon is a not-so-insignificant amount.