The Toba supereruption occurred between 66,000 and 76,000 years ago at Lake Toba (Sumatra, Indonesia), and it is recognized as one of Earth's largest known eruptions. The related catastrophe theory holds that this supervolcanic event plunged the planet into a 6 to 10 year volcanic winter, which resulted in the world's human population being reduced to 10,000 or even a mere 1,000 breeding pairs, creating a bottleneck in human evolution. Some researchers argue that the Toba eruption produced not only a catastrophic volcanic winter but also an additional 1,000 year cooling episode.
The Toba event is the most closely studied supereruption. In 1993 Michael R. Rampino of the New York University and Stephen Self of the University of Hawaii at Manoa first suggested a link between the eruption and a bottleneck in human evolution. The theory was then developed in 1998 by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.