Mega Drought Triggered the Collapse of Ancient Aboriginal Society in Australia

A mega drought, spanning around 1,500 years, triggered the collapse of a prehistoric aboriginal culture in northwest Australia.

The Kimberley region in northwest Australia is home to one of the world's largest collections of rock art that belongs to different culture of the prehistoric aboriginal society.

The rock paintings are in two distinctive art forms - Gwion (Bradshaw) and Wandjina. The Gwion paintings date back to at least 17,000 years ago, with the most recent extending to around 7,000 years ago.

The Wandjina paintings appeared around 4,000 years ago and are continuing till this day. It was not known why there was a gap between the Gwion paintings and the first Wandjina painting to appear. Now, a team of Australian researchers have found evidence that could explain the gap between the two styles of art forms.

The research team was probing the impacts of rapid climate change on the remote Kimberley region, when they discovered that a mega drought caused the Australian summer monsoon to collapse, leading to the demise of the Gwion artists.

They revealed that the Kimberly region encountered a rapid climate change around 5,500 years. Changes in land surface conditions and increase in dust particles in the atmosphere caused the monsoon to fail during that period. This resulted in a mega drought, spanning around 1,500 years.

"Our research shows that the likely reason for the demise of the Gwion artists was a mega-drought spanning approximately 1500 years, brought on by changing climate conditions that caused the collapse of the Australian summer monsoon," Associate Professor Hamish McGowan, from University of Queensland, said in a statement.

After the drought, Wandjina painters are believed to have moved into the region when the climatic conditions became favorable some 4,000 years ago, said the researchers.

The findings suggest that the prehistoric aboriginal populations were susceptible to environmental stresses caused by rapid climate change.

"This is contrary to the conventional view that Australian Aboriginals lived a highly sustainable hunter-gatherer existence in which their knowledge of the landscape meant they adapted to climate variability with little impact," McGowan said.

McGowan and his colleagues indicate that the current abundant seasonal water supplies might fail again, if significant changes to the climate occur.

The findings of the study, "Evidence of ENSO mega-drought triggered collapse of prehistory Aboriginal society in northwest Australia", are published in the journal of Geological Research Letters.