New perspectives on Australian hydroclimate and population dynamics during Last Glacial Maximum and terminal Pleistocene

Abstract

Long-standing interpretations of the Last Glacial Maximum (LGM; 21,000 ± 2,000 years ago) in Australia suggest that the period was one of extreme cold and aridity, during which the Indo-Australian summer monsoon (IASM) system collapsed, and human populations declined and retreated to ecological refuges to survive. Here, we use transient iTRACE simulations, combined with palaeoclimate proxy records and archaeological data to re-interpret the late LGM and terminal Pleistocene (21,000–11,000 yrs) in Australia. The models suggest climates during the peak LGM were cooler than present (-4 to -6°C), but there is no evidence of IASM collapse or substantial precipitation decreases in northern Australia. Kernel Density Estimates (KDE) of archaeological ages show relatively stable and persistent human activity across most regions throughout the late LGM and terminal Pleistocene, consistent with genetic evidence. Spatial coverage of archaeological sites steadily increased across the terminal Pleistocene; however population collapse is not evident.