‘Extreme climate change results in the fundamental social and economic reorganization’
By Summit Voice
FRISCO — The peak of the last ice age, about 20,000 years ago, resulted in huge changes for Aboriginal Australians, who had to deal with expanding deserts, big reductions in rainfall and plummeting temperatures.
“Lakes dried up, forests disappeared, deserts expanded, animals went extinct and vast swaths of the Australian land mass would have been simply uninhabitable,” said Sean Ulm, with James Cook University in Cairns, explaining that the Last Glacial Maximum was the most significant climatic event ever faced by humans in Australia.
To assess how those climatic changes affected aboriginal populations, scientists used advanced geospatial techniques to analyze archaeological radiocarbon dates from across Australia. The research included scientists with the Australian National University and the University of New South Wales, Oxford University in the United Kingdom and Simon Fraser University in Canada. Their findings have been published in the Journal of Archaeological Science.
“The magnitude of change was phenomenal,” said Ulm, a lead researcher on the project and Deputy Director of JCU’s Centre for Tropical Environmental and Sustainability Science. “Sea levels fell more than 120 metres during the LGM, exposing much of the continental shelf and connecting mainland Australia to Papua New Guinea and Tasmania. We are trying to understand how people responded to these extreme conditions,” Ulm said.
The researchers found that during times of high climatic stress, human populations contracted into localised environmental refuges in well-watered ranges and along major riverine systems, where water and food supplies were reliable.
“As much as 80 per cent of Australia was temporarily abandoned by Aboriginal people at the height of the LGM, when conditions were at their worst,” said Alan Williams, with the Fenner School of Environment and Society at The Australian National University.
“Along Australia’s east coast, people contracted to refuge areas with good water supplies … most likely the result of increased summer snow melt coming off mountain ranges like the Victorian Alps, or glacier-fed river systems such as those of the central highlands of Tasmania.”
Ulm said that, while those better-watered areas would have provided more reliable resources, Aboriginal people needed to make significant changes to their way of life in order to survive.
“The archaeological evidence reflects major changes in settlement and subsistence patterns at this time. Many previously occupied areas were abandoned,” he said. “There were changes to hunting practices, the types of food people were eating, and the technologies they were using, to deal with new circumstances.
“We expect there would have been huge impacts on social relationships and religious beliefs as well, but these types of changes are much harder to detect in the archaeological record … One thing we can say for sure is that extreme climate change results in the fundamental social and economic reorganization of society.
“This was certainly true in the past and will be true in the future,” he concluded.