According to the authors of a new study, European colonization of the Americas killed 10% of the world population and caused a period of global cooling! The first European contact in 1492 brought diseases to the Americas which decimated the native population and the resultant collapse of farming and reduction in land use in the Americas was so significant that it caused a drop in atmospheric CO2 levels and likely contributed to the global drop in temperatures in the 17th century.
Here is a summary of the findings of the researchers from University College London (mainly culled from the shorter article by the authors at theconversation.com/…) —
- The authors used multiple methods to arrive at an estimate of pre-Columbian indigenous population of the Americas at 60m in 1492. For comparison, Europe’s population at the time was 70-88m spread over less than half the area.
- About 62m hectares of land, or about 10% of the landmass of the Americas, had been farmed or was under other human use when Columbus arrived. For comparison, in Europe 23% and in China 20% of land had been used by humans at the time.
- European arrival in 1492 lead to 56 million deaths by 1600 - 90% of the pre-Columbian indigenous population and around 10% of the global population at the time.
- Native Americas at that time had never been in contact with the pathogens brought by the colonists and had no immunity to them. Waves of smallpox, influenza and measles created Virgin soil epidemics and decimated the population. Warfare, famine and colonial atrocities did the rest.
- The large population reduction led to reforestation of 55.8m hectares and 7.4 PgC (1 PgC = 1 billion tons of carbon) uptake from the atmosphere.
- Enough CO₂ was removed from the atmosphere that it contributed to the coldest part of the Little Ice Age.
- The lower temperatures created a feedback in the carbon cycle which removed even more CO₂ from the atmosphere – such as less CO₂ being released from the soil.
- This explains the drop in CO₂ at 1610 seen in Antarctic ice cores, solving an enigma of why the whole planet cooled briefly in the 1600s. During this period, severe winters and cold summers caused famines and rebellions from Europe to Japan.
- The unprecedented reforestation event in the Americas led to a reduction of 5 parts per million CO₂ from the atmosphere – only about three years’ worth of fossil fuel emissions today.
Here is a graph showing the grim population collapse stats in Mexico from one study. Other studies contribute the collapse to a combination of slavery, poor living conditions, starvation, malnutrition and diseases.
Population collapse in the 16th century in Mexico according to one study. 85% of the population was wiped out in the first 50 years. From en.wikipedia.org/...
The little ice age started before 1492, but was exacerbated in the 17th century by reduced anthropogenic land use. en.wikipedia.org/...
www.sciencedirect.com/…
TSI = Total Solar Irradiation
LUC = Land Use Change
Also shows that TSI and volcanic activity were not correlated with the observed anomaly in CO2 and global temperatures between 1550 and 1700.
The authors conclude that “the Great Dying of the Indigenous Peoples of the Americas led to the abandonment of enough cleared land in the Americas that the resulting terrestrial carbon uptake had a detectable impact on both atmospheric CO2 and global surface air temperatures in the two centuries prior to the Industrial Revolution.”
Please take a look at the full paper for details not covered here.
The study also indicates that planting more trees will not solve the Climate Change threat that faces us in this century. The Great Dying resulted in an area the size of France being reforested and that gave us only a few ppm of CO2 reduction, worth just 2-3 years of fossil fuel emissions at the present rate. We will have to reduce our carbon footprint.
The Little Ice Age
From en.wikipedia.org/… —
The Little Ice Age (LIA) was a period of cooling that occurred after the Medieval Warm Period. It has been conventionally defined as a period extending from the 16th to the 19th centuries, but some experts prefer an alternative timespan from about 1300 to about 1850.
The NASA Earth Observatory notes three particularly cold intervals: one beginning about 1650, another about 1770, and the last in 1850, all separated by intervals of slight warming.
Several causes have been proposed: cyclical lows in solar radiation, heightened volcanic activity, changes in the ocean circulation, variations in Earth's orbit and axial tilt (orbital forcing), inherent variability in global climate, and decreases in the human population (for example from the Black Death and the colonization of the Americas).
Epilogue
We have all read about the “Great American Dying”, thanks to the writings of Jared Diamond (Guns, Germs, and Steel), Charles Mann (1493: Uncovering the New World Columbus Created), Howard Zinn (A People's History Of The United States) and others. We have also known about the effects of forests and deforestation on atmospheric CO2. Others have studied the link between historical depopulation events, reforestation and their affect on climate. But this seems to be a landmark study that has comprehensively and quantitatively described how this American genocidal period affected global temperatures.
Just reading through this part of our history sickens one to the stomach, and now we have this. It is also a grim reminder of our history that few pay attention to — that we non-native-Americans wiped out 90% of a flourishing indigenous population, an estimated 56 million lives.
References
- Earth system impacts of the European arrival and Great Dying in the Americas after 1492 —Alexander Koch, Chris Brierley, Mark M. Maslin and Simon L. Lewis — www.sciencedirect.com/…
- European colonisation of the Americas killed 10% of world population and caused global cooling — theconversation.com/…
- America colonisation ‘cooled Earth's climate’ — www.bbc.com/…
- Mass Deaths in Americas Start New CO2 Epoch (2015)— www.scientificamerican.com/…
- The Columbian Encounter and the Little Ice Age: Abrupt Land Use Change, Fire, and Greenhouse Forcing (2010) — www.tandfonline.com/...
- Population history of indigenous peoples of the Americas — en.wikipedia.org/…
- Native Voices: Native Peoples’ Concepts of Health and Illness — wsearch.nlm.nih.gov/…
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400 PPM: Can Artificial Trees Help Pull CO2 from the Air? — www.scientificamerican.com/...
