Australian Precipitation Extremes over the last Millenia: How do Ephemeral Lake Records Compare Against Climate Models?

The flooding in Queensland and NSW over the last years has affirmed the impacts that extreme precipitation has on peoples lives and their livelihood. To be better prepared for such extremes in the future we need to know how often and under which climatic circumstances they occur. However, climate models for Australia still involve high uncertainty in predicting the likelihood of precipitation extremes that lead to large flooding events. This is attributed to the limited record of hydro-climatic paleo data across Australia. Though efforts have been made to improve the record of past precipitation extremes, previous studies have focused on high resolution at specific locations rather than a large spacial coverage.

Our project tackles this challenge by utilising the strongly link between precipitation and filling events of ephemeral lakes. The paleoenvironmental evidence collected from various ephemeral lakes in key quadrants of the country allows the establishment of a hydro-climatic paleo record on a large spatial scale. A timeframe of the last thousand years permits the comparison of frequency and magnitude to inter-annual variability of precipitation extremes in different regions across Australia. Ultimately, a comparison of the established record against other paleo data and an analysis of global climate simulations will result in an improved understanding of past precipitation extremes and the importance varying climatic drivers have in different regions across Australia.