New Scientist
Image: widakso
In the face of global climate change 74,000 years ago, humans came up trumps. Evidence from India shows that the global cooling following a massive volcanic eruption at the time did not decimate human populations as originally thought.
The eruption of Toba volcano in Sumatra, Indonesia – the largest of the past 2 million years – coincided with the onset of glacial conditions. This has led some people to link the two events, says Michael Petraglia of the University of Cambridge. Some have proposed that human populations shrank during the “volcanic winter” following the eruption, but Petraglia’s team thinks otherwise.
At its study site in southern India, the team found stone artefacts immediately above and below a 2.5-metre-thick layer of Toba ash (Science, vol 317, p 114). “The stone tool assemblage surprised us because there was no dramatic technological change across the ash,” says Petraglia. “Our conclusion was that the eruption didn’t necessarily wipe out populations.”
The first modern humans shared their world with a number of other human species, he says. Homo erectus was among the oldest, having first appeared 2 million years ago. All these species lived through the Toba volcanic eruption. “There is evidence of Homo erectus at 50,000 years ago, and Homo floresiensis appeared 90,000 years ago and was still around 13,000 years ago. So archaic human species survived the event too,” Petraglia says.
