Time Lines
First of all, we note that the great civilisations of antiquity were marked by a curious synchronicity in the times of their demise. There is an extensive literature about the sudden "collapse" of leading societies of the mid-East at the close of the Bronze Age, for example. There is evidence of drought and conflict and the fall of empires, for example the Hittites, caused by famine and invasion by 'climate refugees' from that time (Robbins 2001, Linden 2006). But not only was 1200BCE a "Year of the Apocalypse", as it has been called: there are other climate-driven apocalypses peppered throughout the record of the Holocene, from the near-East (Staubwasser and Weiss 2006, Arz et. al., 2006) to China (Wenxiang and Tungsheng,2004) to the Americas (Wahl et. al. 2006, Kloor 2007). Surely, if agricultural crises were driven by internal forces such as poor farming practices or social inequities, one would would expect the archaeological record to reveal a randomised spread of such events? This is not what we see.
There is much evidence that humans first colonized Sahul (the combined Australia–New Guinea landmass) about 50,000 years ago . Australia and New Guinea were joined as one land mass until land bridges were inundated by the sea when continental ice sheets melted at the close of the Pleistocene epoch around 10,000 years ago. However, the widely promulgated claim that modern Australian aboriginal people are the direct descendants, in unbroken succession, of those self-same humans who colonised Sahul 500 centuries ago is an assertion that is not supported by either genetic studies or by archaeology.
