Historical climate change on the Arabian peninsular, hominin occupation and the pattern of Aboriginal settlement of Sahul

The second lecture in my introductory course on the history of Australia's New England, the Tablelands and surrounding river valleys, traces the journey of the Aboriginal and Papuan ancestors from Africa until their arrival on the mega continent we now call Sahul. 

On 1 September 2021 an article by H S Groucutt et al was published in Nature that bears upon our story. The abstract including link to the paper follows. Comments follow the abstract.  

Pleistocene hominin dispersals out of, and back into, Africa necessarily involved traversing the diverse and often challenging environments of Southwest Asia. Archaeological and palaeontological records from the Levantine woodland zone document major biological and cultural shifts, such as alternating occupations by Homo sapiens and Neanderthals. However, Late Quaternary cultural, biological and environmental records from the vast arid zone that constitutes most of Southwest Asia remain scarce, limiting regional-scale insights into changes in hominin demography and behaviour. Here we report a series of dated palaeolake sequences, associated with stone tool assemblages and vertebrate fossils, from the Khall Amayshan 4 and Jubbah basins in the Nefud Desert. These findings, including the oldest dated hominin occupations in Arabia, reveal at least five hominin expansions into the Arabian interior, coinciding with brief ‘green’ windows of reduced aridity approximately 400, 300, 200, 130–75 and 55 thousand years ago. Each occupation phase is characterized by a distinct form of material culture, indicating colonization by diverse hominin groups, and a lack of long-term Southwest Asian population continuity. Within a general pattern of African and Eurasian hominin groups being separated by Pleistocene Saharo-Arabian aridity, our findings reveal the tempo and character of climatically modulated windows for dispersal and admixture.

Groucutt, H.S., White, T.S., Scerri, E.M.L. et al. Multiple hominin dispersals into Southwest Asia over the past 400,000 years. Nature (2021). https://doi.org/10.1038/s41586-021-03863-y

Comment

To the best of our present knowledge, the ancestors of the Aboriginal and Papuan peoples came out of Africa arriving in Sahul perhaps 65,000 years ago. This was during the Pleistocene, a period marked by ice ages separated by warmer periods. 

Today, Saudi Arabia is marked by arid deserts. This study suggests that the Arabian Peninsula experienced wetter green periods approximately 400, 300, 200, 130–75 and 55 thousand years ago. Each period was marked by different hominin occupations, with people withdrawing and reoccupying as the climate changed. 

From our viewpoint, the green period from 130-75,000 years ago would appear to fit with Aboriginal migration patterns given the present earliest indicated occupation date of c65,000 years ago.  

Postscript 

 An article in the Conversation  provides more commentary. Research reveals humans ventured out of Africa repeatedly as early as 400,000 years ago, to visit the rolling grasslands of Arabia