(New Scientist) It was the biggest bang in human history. Around 75,000 years ago, the Toba supervolcano exploded on the Indonesian island of Sumatra, blasting enormous volumes of gas and ash into the air. Yet a new analysis suggests it had little impact on the climate, or on humans. So could such vast eruptions be survivable?
Supervolcanoes are capable of releasing more than 1000 cubic kilometres of material in one eruption, enough to cover an entire continent with ash. There are only six supervolcanoes on Earth, the most famous being Yellowstone. Toba was the last to erupt.
Toba’s eruption produced vast quantities of sulphur dioxide, a gas that behaves in the opposite way to a greenhouse gas – it cools Earth by increasing the atmosphere’s ability to reflect the sun’s rays back into space. Archaeologists and volcanologists have suggested that this triggered a 1000-year volcanic winter that wiped out a significant proportion of the planet’s people and plants. But this idea has proved controversial, and the latest evidence makes it look even less likely.