Super volcano eruptions and their impact on hominin evolution

Discussions relating to super-volcanic eruptions (Volcanic Explosivity Index 7-8+) and their impacts on hominin evolution tend to focus on eruptions that occurred within the last 100 kya and specifically relate to the impact on modern humans or Neanderthals (e.g. Ambrose 2003; Fitzsimmons et al. 2013). What is less understood is whether global super-eruptions may have had an impact on Palaeo-climates and hominin evolution for non-Homo or early-archaic Homo species. This paper presents the results of a new study that suggest there may be some correlation between hominin speciation / extinction and super-volcanic eruptions that are worthy of further investigation. Previous studies using first and last hominin appearance dates over the last 5 mya 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). From the correlations presented within this paper it would seem that volcanic super-eruptions tend to occur immediately prior to a dramatic shift in global temperature (measured using the LR04 Benthic Stack - Lisiecki and Raymo 2005) and may therefore have an enhancing effect on orbitally induced climatic cycles that drove hominin speciation events. In addition, a number of super-eruptions seem to occur prior to technological changes in the hominin behavioural record which may add supportive evidence to the notion that climatic instability may have been a stimulus to the development of stone tool technologies and increasingly complex behaviours within hominin evolution (Grove 2011; 2012b). If it is accepted that competition between species against a back drop of climatic instability may lead to their extinction (Grove 2012a), then super-eruptions may have acted as the critical enhancers to orbital forcing events that drove the majority of hominin evolution within the last 5 mya.