The Toba “super volcanic” eruption 74,000 years ago had a massive impact on human evolution. In size it dwarfed Krakatoa and Tambora emitting 2,800 cubic km (about 670 cubic miles) of ash and lava or about about 200 times larger than Krakatoa. It cooled the earth by ~3 C for a period of about 10 years. Parts of Indonesia, India and the Indian Ocean were covered by 15 centimeters of volcanic debris. Human populations outside Africa suffered severely in the short term due to food shortages. Some have estimated that just a few thousands individuals survived this period. Our DNA today is all derived from this small pool.
Volcanoes cool the planet by increasing global albedo and cutting out sunlight. Their imprint can be seen in the current global temperature data.
The severn largest volcanic eruptions in the last 270 years compared to Global Temperatures. The 3 largest eruptions all occurred before 1850. CRUTEM4 is shown in Green.
Luckily Toba is not due to erupt again for another 600,000 years!
Not long ago we learned that 19,000 undersea volcanoes were recently discovered. While the ash will not get into the atmosphere is their output of CO2 accounted for?
earthsky.org/earth/19000-un
I doubt it.
Another interesting question is why the bottom of the ocean is not covered in ice – not even in the Arctic !
This implies a heat source coming from the earth itself.
“Human populations outside Africa suffered severely in the short term due to food shortages. Some have estimated that just a few thousands individuals survived this period. Our DNA today is all derived from this small pool.”
This is most likely wrong. There is no evidence that any other animal species or even the ecosystems in the volcano region suffered any kind of catastrophe. A human-only volcanic catastrophe is extremely unlikely.
And volcanoes, even the biggest ones, have an acute and short effect. For a real catastrophe you need something like an igneous province, like the Deccans.
Do we know there were no species extinctions following Toba ?
Of course. People should not pay credit to all those catasthropic tales from the past or in the future. How many Asian species show a genetic bottleneck at the time of the Toba supereruption?
Singh, A. and Srivastava, A.K., 2022. Had youngest Toba tuff (YTT, ca. 75 ka) eruption really destroyed living media explicitly in entire Southeast Asia or just a theoretical debate? An extensive review of its catastrophic event. Journal of Asian Earth Sciences: X, p.100083.
Smith, E.I., Jacobs, Z., Johnsen, R., Ren, M., Fisher, E.C., Oestmo, S., Wilkins, J., Harris, J.A., Karkanas, P., Fitch, S. and Ciravolo, A., 2018. Humans thrived in South Africa through the Toba eruption about 74,000 years ago. Nature, 555(7697), pp.511-515.
Lane, C.S., Chorn, B.T. and Johnson, T.C., 2013. Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka. Proceedings of the National Academy of Sciences, 110(20), pp.8025-8029.
Volcanoes have very little effect on climate despite contrary popular and scientific beliefs.
You may well be right !
Ice Ages do though 😉
Hello Clive Best
Last year I forgot to add a little comment to this interesting thread.
Here is an interesting article about the Toba eruption
New insights into the ???74?ka Toba eruption from sulfur isotopes of polar ice cores
Laura Crick, Andrea Burke, William Hutchison, Mika Kohno, Kathryn A. Moore, Joel Savarino, Emily A. Doyle, Sue Mahony, Sepp Kipfstuhl, James W. B. Rae, Robert C. J. Steele, R. Stephen J. Sparks, and Eric W. Wolff (2021)
https://cp.copernicus.org/articles/17/2119/2021/
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Of particular interest to me personally was their reference to the Samalas eruption of 1257 on the island of Lombok, which I had known about since reading the article by Lavigne & al.
Source of the great A.D. 1257 mystery eruption unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia
Franck Lavigne, Jean-Philippe Degeai, Jean-Christophe Komorowski and Edouard de Belizal (2013)
https://www.pnas.org/doi/full/10.1073/pnas.1307520110
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Today I discovered another interesting UK paper – about Samalas:
Utilising a multi-proxy to model comparison to constrain the season and regionally heterogeneous impacts of the Mt Samalas 1257 eruption (2024)
Laura Wainman, Lauren R. Marshall, and Anja Schmidt
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Javier Vinós is an unconditional supported of the ‘It’s the Sun alone’ ideology, as we best understand when he writes
” Volcanoes have very little effect on climate despite contrary popular and scientific beliefs. ”
No wonder then that he doesn’t give much to the influence of volcanism on climate, as described for example in
Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks
Gifford H. Miller & al. (2011)
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL050168
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Best greetings from Germoney
Thanks for the link !
I note the following:
“Intervals of sudden ice growth coincide with two of the most volcanically perturbed half centuries of the past millennium. A transient climate model simulation shows that explosive volcanism produces abrupt summer cooling at these times, and that cold summers can be maintained by sea-ice/ocean feedbacks long after volcanic aerosols are removed.”