In a groundbreaking discovery, scientists have unveiled evidence of a lost continent off Australia’s northern coast, known as the North West Shelf, nearly twice the size of the UK.1 This submerged landmass, submerged in the Timor Sea around 10,000 years ago due to rising sea levels, once housed a thriving population of half a million people approximately 70,000 years ago.2 The revelation challenges assumptions about the productivity of continental margins, shedding light on the dynamic history of human habitation in the region.
The North West Shelf, often referred to as the ‘Atlantis’ of Australia, stretched between the Kimberley and Arnhem regions, forming part of the supercontinent Sahul that connected Australia, New Guinea, and Tasmania. Sonar mapping has uncovered traces of rivers, freshwater lakes, and a large inland sea that once defined this now-submerged territory. “We’re talking about a landscape that’s quite submerged, over 100 meters below sea level today,” explains Kasih Norman, lead author of the study.
A Staged Migration: Connecting Lost Continents
The vastness of the North West Shelf played a pivotal role in human migration, acting as a possible ‘stepping stone‘ between Indonesia and Australia. Between 71,000 and 59,000 years ago, lowered sea levels exposed a necklace of islands within reach of Southeast Asia, creating a contiguous archipelago environment. This facilitated what Kasih Norman calls a “staged migration” between Indonesia and Australia. The region’s potential to support life is highlighted by evidence of sheltered escarpments, an inland sea, a large freshwater lake, and winding river beds.
The demise of the North West Shelf began around 18,000 years ago with the end of the last ice age and subsequent global warming. Rapid sea level rises between 14,500 to 14,100 years ago and 12,000 to 9,000 years ago led to the inundation of half of the North West Shelf. Human populations witnessed the encroaching coastline, prompting a retreat further into the Australian mainland. This retreat is evident in increased populations in the Kimberley and Arnhem regions, marked by distinctive new rock art styles.
Kasih Norman’s study challenges the assumption that continental margins were unproductive, suggesting that the North West Shelf could have supported a population ranging from 50,000 to half a million people. Clues from the archaeological record, including stone tools found off the coast of the Pilbara region, support the idea of a once-habitable plateau that was home to hundreds of thousands of people. As sea levels rose, these inhabitants were forced to retreat, leaving behind a continent-worth of lost traces of changing genetic signatures and increased stone tool deposits at the edge regions of modern-day Australia.
Final Thoughts
The discovery of the lost continent off Australia’s coast opens a window into the dynamic history of human habitation in the region. From a once-thriving landscape that connected continents to a submerged realm lost to rising sea levels, the North West Shelf’s story challenges preconceptions about ancient continental margins. As researchers uncover more about this lost Atlantis, it offers valuable insights into how human populations dynamically responded to environmental changes in the past—a narrative that may hold lessons for addressing future challenges such as climate change and sea level rise.