Quiz 3: Australia’s Indigenous population may have been 3 million, study finds

A new study shows that the Indigenous population of Australia may have once reached 3 million. The figure is three times the largest previous estimate, which ranged from 30,000 to 1 million. 

Australia was colonised by Britain in 1788. These early settlers, who brought new diseases and began a period of devastating violence, made no organised effort to count the Aboriginal population. 

The study was funded by the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage. It used powerful computer modelling to look at the ecological, human and climate factors that existed on Australia before the arrival of Europeans. Computer models use data to explain things that may have happened in the past. Ecology is the relationship between living things and the environment. 

Australia and New Guinea were part of one landmass until about 10,000 years ago. Around this time, the last ice age ended and the sea level rose, drowning the land beneath the waters of what is now Torres Strait. The same thing happened to the land joining mainland Australia to Tasmania. This mega-continent was known as Sahul, and scientists think its human population could have been as high as 6.5 million. 

Landmass Was Much Larger Before Ice Age

The researchers studied how much land surrounded Australia before the last ice age ended. They calculated there were 2 million square kilometres more coastal plain exposed compared with today. The larger landmass could have been home to more people. The former coastal lands, which are now underwater, are expected to hold many significant archaeological sites.

Sean Ulm from James Cook University in Queensland worked on the study. Ulm said previous studies on Australia's pre-colonial population numbers were flawed. "When Europeans began calculating, there had been decades of population reduction from introduced diseases and frontier violence."

"We are using a different set of principles to come at the same problem," Ulm said. This time, scientists were asking "what is the human, cultural and ecological principles about the productivity of the land from 60,000 years ago". 

Professor Corey Bradshaw of Flinders University said the estimated figure of 3 million people within the area covered by modern-day Australia was probable. "There's no ecological evidence for the estimate to be lower at the time of the late Pleistocene," Bradshaw said. The late Pleistocene era, or time period, ended around 11,700 years ago. 

Mapping Out Migration Pathways

Bradshaw said the research team was already being asked by archaeologists from around the world to apply its formula to other continents. The team would also apply the model to later time periods.

The same scientists also studied how, when and where people trekked across the continent. They mapped out the most likely migration pathways, or "superhighways", people used when they moved across the land. The study found it could have taken humans just 5,000 years to populate and settle right across the country.

Professor Stefani Crabtree was the lead author of the superhighways study. Crabtree is an archaeologist at Utah State University in America. She said that when people entered a new landscape they would "want to know how to move efficiently, where to find water and where to camp" and would have located high points for a better view of the land around them.