The Toba super-eruption and the disputed 'volcanic winter'

Date

c. 74,000 years ago

Category

Environment & climate

Region

Sumatra (Indonesia); global ash dispersal

Era

Prehistory

Significance

Around 74,000 years ago the Toba volcano in Sumatra produced one of the largest eruptions of the Quaternary, ejecting roughly 2,800 cubic kilometres of material and blanketing South Asia in a layer of ash still traceable today.

Older versions of the 'Toba catastrophe hypothesis' argued that the eruption triggered a multi-year volcanic winter and a severe global cooling that crashed human populations to a few thousand individuals, leaving a genetic bottleneck visible in modern DNA. More recent work has substantially revised this picture. Refined climate models suggest cooling was strongly concentrated in the Northern Hemisphere, with little change across much of the tropics and Southern Hemisphere. Crucially, archaeological sequences at sites such as Dhaba and Jwalapuram in India, and locations in southern Africa, show human and stone-tool continuity straight through the ash horizon, implying that people in many regions were largely unaffected. The eruption remains a key chronological marker for dating Palaeolithic deposits across Asia, but its role as a near-extinction event for humanity is now widely regarded as overstated.

Related environment & climate events

• The Pleistocene–Holocene boundary and the start of the Holocene
  c. 11,700 years ago (c. 9700 BCE)
• End of the African Humid Period and Desertification of the Sahara
  c. 3500–2700 BCE
• Late Pleistocene megafaunal extinctions and the overkill-vs-climate debate
  c. 15,000 – 10,000 years ago
• The 8.2-kiloyear abrupt cooling event
  c. 6200 BCE
• The Last Glacial Maximum and human refugia
  c. 26,500 – 19,000 years ago
• The Younger Dryas cold reversal
  c. 12,900 – 11,700 years ago

Further reading

A New Green History of the World

The wider story

A New Green History of the World

Clive Ponting

The classic accessible account of how environment and climate have shaped human history.

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