Super-volcanic eruptions and impacts on hominin evolution

<p>The impact of super volcanic eruptions (Volcanic Explosivity Index 7-8+) on human evolution is a topic that has invited much debate and controversy (Ambrose 1998, Petraglia et al. 2007, 2012; Clarkson et al., 2020), and has typically focused on the impacts on human populations within the last 100-200kya (e.g. Groucutt 2020). What is less well understood is whether there is any clear evidence to show how super-volcanic eruptions, and their subsequent impacts on paleo-environments and climates, may have influenced hominin evolution over the last c. 5mya. Previous studies using first and last hominin appearance dates have suggested that orbitally-induced climatic cycles (eccentricity, obliquity and precession) may play a role in hominin speciation events, but that only obliquity shows any significant relationship with extinction events (Grove 2012a). Firth and Cole (2015) subsequently suggested that selected super-eruptions may have acted as critical enhancers to particular orbital forcing events.</p><p> </p><p>This paper revisits the Firth and Cole (2015) study and presents a comparison of super volcanic eruptions against first and last hominin appearance dates; orbitally induced climatic cycles; global temperature (measured using the LR04 Benthic Stack – Lisiecki and Raymo 2005); and broad technological behavioural changes in order to assess to what extent such eruptions may have impacted, either directly or indirectly, on human evolution at different temporal and geographic scales. Such large eruptive events certainly do seem to disrupt climatic conditions for significant periods of time at a generational level (Harris 2008). Where data is fine grained enough, volcanic activity also seems to impact on human population dispersals, through push and pull factors, and drive changes in the behavioural record (e.g. Groucutt 2020). However, at the broad evolutionary scale, volcanic eruptions do not seem to lead to a significant turnover of hominin species (at least in regard to the resolution of the data currently available). Therefore, we suggest that future work should seek to bring these two perspectives of scale together to better understand super volcanoes in terms of the complex interplay of changing local conditions and their impacts on the broader global picture of human evolution.</p><p> </p><p> </p><p>References:</p><p>Ambrose, S.H., 1998. Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans. Journal of Human Evolution. 34, 623–651.</p><p>Clarkson, C. et al. 2020. Human occupation of northern India spans the Toba super-eruption ~74,000 years ago. Nature Communications 11: 961.</p><p>Firth C.R. and Cole J. 2015: A review of super-volcano eruptions and their impact on hominin evolution. INQUA XIX Congress: Japan, July.</p><p>Groucutt, H. 2020. Volcanism and human prehistory in Arabia. Journal of Volcanology and Geothermal Research 402: 107003.</p><p>Harris, B. 2008. The potential impact of super-volcanic eruptions on the Earth’s atmosphere. Weather 63 (8): 221 – 225.</p><p>Petraglia, M.D., et al.,  2007. Middle Paleolithic assemblages from the Indian subcontinent before and after the Toba super-eruption. Science 317, 114–116.</p><p>Petraglia, M.D., Korisettar, R., Pal, J.N., 2012. The Toba volcanic super-eruption of 74,000 years ago: climate change, environments, and evolving humans. Quaternary International. 258, 1–4.</p>