The Colossal Toba Super-Eruption 74,000 Years Ago Led to Near Extinction of Homo-Sapiens

[steven johnson]

A genetic bottle neck has been calculated to have occurred approximately 70,000 years ago when all mammalian species gentetic diversity dramatically contracted -- presumably due to the 6-10 years of volcanic winter than decimated the food chainl.

Newly discovered archaeological sites in southern and northern India have revealed how people lived before and after the colossal Toba volcanic eruption 74,000 years ago. Several theories suggest that the Toba eruption plunged the planet into a 6 to 10 year volcanic winter that endangered the world's human population, reducing it to 10,000 or a mere 1,000 breeding pairs. Some researchers argue that the Toba eruption produced a 1,000 year cooling episode.

An international, multidisciplinary research team, led by Oxford University in collaboration with Indian institutions, unveiled to a conference in Oxford what it calls 'Pompeii-like excavations' beneath the Toba ash. The seven-year project examines the environment that humans lived in, their stone tools, as well as the plants and animal bones of the time. The team has concluded that many forms of life survived the super-eruption, contrary to other research which has suggested significant animal extinctions and genetic bottlenecks.

Although some scholars have speculated that the Toba volcano led to severe and wholesale environmental destruction, the Oxford-led research in India suggests that a mosaic of ecological settings was present, and some areas experienced a relatively rapid recovery after the volcanic event.

Dr Petraglia said: 'This exciting new information questions the idea that the Toba super-eruption caused a worldwide environmental catastrophe. That is not to say that there were no ecological effects. We do have evidence that the ash temporarily disrupted vegetative communities and it certainly choked and polluted some fresh water sources, probably causing harm to wildlife and maybe even humans.'

The Colossal Toba Super-Eruption 74,000 Years Ago Led to Near Extinction of Homo-Sapiens
The Colossal Toba Super-Eruption 74,000 Years Ago Led to Near Extinction of Homo-Sapiens

[msongs]

1. interesting 1 hr. program on this on pbs, might on pbs.org site nt

[aquart]

2. Terrifying.

[unhappycamper]

3. When Krakatoa went boom in 1883, the explosion was heard around the earth

five times. You know all those painting in the late 1880s & 1890s with great sunsets? Krakatoa.

[AlecBGreen]

4. The Toba eruption

left a crater 50 miles across in Indonesia. That was a big boom!

[Fumesucker]

5. Tambora was considerably more energetic than Krakatoa

http://en.wikipedia.org/wiki/Mount_Tambora

Tambora erupted in 1816 with a rating of seven on the Volcanic Explosivity Index, making it the largest eruption since the Lake Taupo eruption in about 180 CE.<4> The 1815 eruption of Tambora was the largest volcanic eruption in recorded history. The explosion was heard on Sumatra island (more than 2,000 km (1,200 mi) away). Heavy volcanic ash falls were observed as far away as Borneo, Sulawesi, Java and Maluku islands. Most deaths from the eruption were from starvation and disease, as the eruptive fallout ruined agricultural productivity in the local region. The death toll was at least 71,000 people (the most deadly eruption in recorded history), of whom 11,000–12,000 were killed directly by the eruption;<4> the often-cited figure of 92,000 people killed is believed to be an overestimate.<5> The eruption created global climate anomalies; 1816 became known as the "Year Without a Summer" because of the effect on North American and European weather. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of the 19th century.

Kratatoa was a 6 on the VEI while Tambora was a 7..

http://en.wikipedia.org/wiki/Volcanic_Explosivity_Index

[Odin2005]

7. I've read that before Krakatoa's 535AD eruption Sumatra and Java were joined.

Krakatoa linked the two islands, but the 535 eruption left a volcanic crater that severed the connection between the islands. That eruption caused a lot of problems world-wide and the bad weather it caused may have contributed to the plague epidemic that happened at the time in many parts of Eurasia.

[Bigmack]

6. Fascinating and another reminder that

our species hold on "long term" survival is a touch tenuous. If we don't do ourselves in from our chronic "overshoot," old mom (as in nature) will get us in the end anyway. Ms Bigmack