Some 74,000 years ago, a volcanic super-eruption 5,000 times larger than Mount St. Helens spurred a “volcanic winter” that lasted up to a decade, resulting in a millennia-long cooling event across the planet that wiped out early human species and mammals alike.
Or so the theory went.
Now, new evidence presented in Nature Communications suggests that while the Toba Volcano eruption was one of the largest events to occur over the last 2 million years, it may not have wiped out early humans but instead proved the species to be adaptable and ingenious in times of climate catastrophe.
Previous theories suggest that the volcanic eruption decimated early human populations, nearly forcing the extinction of humans. Under this theory, the few Homo sapiens that survived in Africa during this time developed social, symbolic, and economic strategies that enabled them to re-expand to Asia 14,000 years after the eruption. New work contradicts such theories, suggesting that humans in India were resilient to the volcano eruption – even though they ultimately died off later and did not contribute to modern gene pools.
"The archaeological record demonstrates that although humans sometimes show a remarkable level of resilience to challenges, it is also clear that people did not necessarily always prosper over the long term,” said Professor Michael Petraglia, of the Max Planck Institute, in a statement.
Archaeologists at the Dhaba site in central India dated 13 sediment samples spanning an 80,000 year-long stratigraphic record from the Dhaba site in northern India’s Middle Son Valley, as well as found a rich collection of artifacts over a timeframe of 55,000 years surrounding the volcanic eruption. Stone tools discovered near the Toba eruption represent those from the African Middle Stone Age and some of the earliest artifacts from Australia, which suggests strong evidence that Middle Paleolithic tool-using populations were present in India before and after the eruption, filling a “major chronological gap” in human records.
"Populations at Dhaba were using stone tools that were similar to the toolkits being used by Homo sapiens in Africa at the same time. The fact that these toolkits did not disappear at the time of the Toba super-eruption or change dramatically soon after indicates that human populations survived the so-called catastrophe and continued to create tools to modify their environments,” said lead author Professor Chris Clarkson of the University of Queensland.
Sediment analyses also suggest that the Earth’s cooling event following the Toba eruption may have been less extreme than previously hypothesized and may not have actually caused the glacial period that followed. The work supports the hypothesis that human populations were present in India 80,000 years ago and likely survived one of the largest volcanic eruptions in the last 2 million years.
India is a “critical geographic crosswords” for understanding how early Homo sapiens dispersed out of Africa, into Asia and beyond. Fossil evidence from the study suggests that humans migrated out of Africa and expanded across Eurasia and interbred with ancient humans, like Neanderthals, before the end of the cooling event 60,000 years ago.