Did mega-drought destroy Aboriginal culture?

By Joanna Egan 17 December 2012
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A new study suggests that ancient Kimberley rock art may record the demise of a local Aboriginal culture.

THE INTERVAL BETWEEN TWO styles of rock art in the Kimberley could be explained by a 1500-year-long mega-drought, new research suggests.

The remote Kimberley region of northwest Australia is home to one of the world’s largest collections of rock art. The paintings are characterised by two distinct forms: the Gwion Gwion, or Bradshaw, figures, which date from 17,000 to about 5000 years ago, and the Wandjina figures, which emerged approximately 4000 years ago and continue today.

New research reveals rapid natural climate change forced the collapse of the region’s annual wet season about 5500 years ago. This resulted in an intensely arid period that lasted about 1500 years, before climate conditions adjusted to a level similar to that which we see today.

Climate change caused a gap in Aboriginal history

In a paper published  in the Geophysical Research Letters, researchers suggest this period of rapid climate change, which coincides with the gap between the two art styles, was a likely catalyst for the disappearance of Gwion Gwion figures and the emergence of Wandjina paintings.

“Our research is the first to present a long continuous record of environmental change in the Kimberley, which offers a scientifically robust explanation of the probable cause for change in the Kimberley rock art from Gwion (Bradshaw) to Wandjina,” says the paper’s lead author Associate Professor Hamish McGowan, at the University of Queensland.

Gwion Gwion rock art

Gwion Gwion rock art in the Kimberley region. (Credit: University of Queensland)

Hamish and his colleagues conducted analyses of sediments and pollen from a sediment core from the Kimberley to identify shifts in vegetation and aridity, in order to determine historic climate patterns. They concluded that changes in land surface conditions and an increase in dust particles in the atmosphere contributed to a weakening or failure of monsoon rains, and an ensuing mega-drought.

“The natural climate variability appears to have caused a dramatic environmental change in the Kimberley as a result of weaker and/or intermittent summer monsoons,” Hamish says, explaining that tropical humid conditions gave way to a much drier climate.

“Our interpretation is that this [rapid climate change] seems to coincide with the demise of one culture until the climate adjusted and another took its place,” he says. “However, more research is required to fully unpick the impacts of past climate variability on the cultural history of the Kimberley, and to confirm whether or not different rock-art styles equate with a cultural crash or the advent of another ethnic group.”

Death of indigenous culture unfounded: Kimberley expert

Prior to this research, the climate history of the Kimberley during this period was relatively unknown. “The climate work that Hamish and his colleagues have done, the pollen sequence, is really important,” says Professor Peter Veth, chair in Kimberley rock art at the University of Western Australia. “To show that there was a potentially significant change in climate conditions at that time is important and it is new information.”

However, Peter critiques the research paper for its argument about how the simultaneous changes in climate patterns and art styles reveal the collapse of a culture. “The cultural explanations they’ve put forward, about it being the demise of one culture and the beginning of another, are fundamentally flawed,” he told Australian Geographic.

Peter explains that archaeology from occupation sites throughout the Kimberley suggests Aboriginal habitation from about 45,000 years ago until the present.

“They’ve got a coincidence – a gap in the pollen record that fits into what is thought to be the change from Gwions to the very obviously different Wandjina art form,” Peter says. “But to suggest that you’ve had the death of a pre-aboriginal culture and then the migration of a new people is totally unsupported by the linguistics, the genetics and the archaeology.”

“A change in art style does not equate with a new people or a crash – graphic switches occur in the art of Aboriginal Australia in many places,” he says.

Peter agrees that by learning more about the Kimberley’s climate history, researchers will better understand the region’s cultural past and he says more investigations into the Kimberley’s climate history are desperately needed. He says that while this “highly significant and robust climate record is of immense importance”, the archaeology of the Kimberley does not show a break in occupation.

“The suggestion of culture demise is not comprehensive and is not supported,” Peter says. “However we do have evidence for climate change and people signalling very differently in their art.”