The Toba catastrophe, when Homo Sapiens was in real danger of extinction
The news of the eruption of the Eyjafjallajökull volcano, located in Iceland, whose immense ash cloud completely blocked the airspace over the Old Continent, is from 2010. Newscasts around the world interviewed impatient travelers at European airports or others who were forced to use the train to get around.
Not all those travelers, distracted and agitated, stopped to think about the immense risks of a huge-scale volcanic eruption, which could alter the Earth's climate for many years and even put the very existence of our species at risk.
The most destructive eruption in history was that of Tambora, located on the island of Sumbawa, Indonesia. The volcano exploded in April 1815, expelling some 160 kilometer cubes of waste into the atmosphere. It is estimated that around 12,000 people died directly as a result of the eruption, while in total there were 71,000 victims, due to the lack of food caused by the massive relapse of volcanic ash in the fields, up to 1,300 kilometers away from the volcano. The mountain, 4,300 meters above sea level before the explosion, has completely changed, as it is now only 2,851 meters above sea level.
The terrible volcanic eruption of Tambora and the subsequent expulsion into the atmosphere of enormous quantities of ash caused, together with a period of minimal solar activity, a decrease of approximately half a degree in global temperature, enough so that the following year, 1816, was remembered as the year without summer, one of the coldest and most difficult in recent centuries.
Especially in North America, but also in Europe and China, temperatures dropped and a layer of persistent fog did not allow the sun's rays to sufficiently heat the Earth. The subsequent winter was also characterized by extremely low temperatures (-32 degrees Celsius was recorded in New York). Two years of poor harvests threw the world economy into chaos and an estimated 200,000 people died of starvation in Europe alone.
However, the greatest catastrophe in the history of Homo Sapiens occurred 70 millennia ago, with the explosion of a huge volcano that was located in what is now Lake Toba, on the island we today call Sumatra.
The evidence for such a cataclysm is both geological (the deep analysis of the Toba caldera and also several geotechnical surveys of the Greenland ice), and genetic (by studying human genes it was concluded that the entire current population of the planet comes from of a restricted group of humans who lived just 70 millennia ago).
According to the scholar A. J. Coale and other eminent scientists of genetics applied to anthropology and human migrations such as the Italian Luigi Luca Cavalli Sforza, it can be stated that the human population 10 millennia ago was around 30,000 individuals (20,000 Homo Sapiens and 10,000 among Erectus, Neanderthal and Floresiensis).
Just about one hundred millennia ago, the slow expansion of Homines Sapientes began, which led them, in approximately 60,000 years, to colonize the entire planet (excluding Antarctica?). In addition to the African expansion that caused the original language to be divided into the four archaic African language families (Nigerian-Cordovan, Nilo-Saharan, Koisan and the language of the Pygmies), some groups of Sapiens left Africa, probably through the current Strait of Aden (which at that time was joined to Arabia, since in the middle of the ice age the sea level was about 120 meters lower than today) to then head towards southern Asia.
The eminent scholar of ancient demography A. J. Coale also states that the human population 70,000 years ago was approximately 60,000 individuals. But how were they distributed on the planet?
Surely, a good part, say 40% (24,000), had remained in Africa, while the remaining 59% (about 35,000 individuals) were found between: Arabia, the Middle East, India, Indochina, China and present-day Indonesia. According to archaeologist Niède Guidon a restricted group of Homo Sapiens was found in present-day Brazil and came directly from Africa (it is estimated that there could have been no more than 600, or 1% of humanity at that time). It must be remembered that, also 70 millennia ago, Homo Sapiens had not arrived in China (its oldest remains date back to 67 millennia ago) nor in Australia (50 millennia) or Europe and North America (where it arrived only 40 millennia ago).
However, in the area of the world that we today call China, there was already Homo Erectus and a distant cousin of his, with small characteristics, Homo Floresiensis, who was found on the island that we today call Flores.
According to the latest geology studies, it was possible to reach the conclusion that just 70 millennia ago, the volcano that was located in the current Lake Toba (on the island of Sumatra), exploded impetuously (up to a gigaton of TNT in power). It was one of the largest catastrophes in the history of the Earth (the one that caused the extinction of the dinosaurs, 65 million years ago, was, however, much more destructive) and, certainly, it was the largest in the history of the Earth.
During the explosion, approximately one hundred million tons of sulfuric acid were expelled into the atmosphere and then fell on the planet, destroying plants. It is estimated that an immense ash cloud covered the entire globe for approximately 6 years, preventing the sun's rays from heating it.
The average temperature of the Earth, which was already in the middle of the ice age, decreased by about 15 degrees Celsius in the 3 years following the explosion. The fall of the ash was also destructive for plants and animals: it is estimated that in certain parts of India a 6-meter layer of ash covered the ground.
Eminent geneticists such as Lynn Jorde and Henry Harpending argued that the world's population was reduced to no more than 5,000 people (other scholars proposed that even the survivors numbered no more than 1,000 on the entire planet).
How was it possible that Homo Floresiensis, who was on Flores, an island not far from Sumatra, and that Homo Erectus Soloensis, who was on Java, survived such a catastrophe? Probably, their small stature and small physical characteristics suggest that they could have hidden in crevices and caves. They certainly needed a low number of calories to survive and perhaps fed on small rodents for years, until they managed, once the climatic situation improved, to return to living by hunting and harvesting crops.
Most of the Sapiens and the Erectus (the latter were in modern-day China) did not survive the cataclysm. The reduction in temperature caused a fearsome chain effect, since the death of many fruit trees, in addition to many animals, was the indirect cause of the death of 90% of human beings.
Only 5-6000 survived, mainly in Africa, the Middle East and India, and, little by little, they resumed the slow path of colonizing the planet.
What would happen to humanity today if a catastrophe of such dimensions occurred? In addition to the people who would die directly after the disaster, a decrease of 15 degrees Celsius in global temperature would cause terrible food crises, with consequent shortages, which would, in turn, cause epidemics. Perhaps wars and insurrections would break out in order to dominate lands still suitable for agriculture.
The Toba catastrophe should make us reflect, with the purpose of changing our behavior on the planet and respecting Mother Earth. It is true that eruptions are natural and that we cannot do anything to prevent them, but we can transform our way of living so that we do not contaminate the environment, thus avoiding climate change that could be disastrous for the human species.
YURI LEVERATTO
