Reconstructing Australian hydro-climate and temperature for the Pliocene warm period: a near future climate analog

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Global climate change represents one of the major challenges confronting humankind today. The Pliocene time period (5.2 to 2.6 million years ago) is the most recent global warming episode with similar atmospheric CO2 concentrations. It is thus widely regarded as an analog to our future climate at the end of the 21st century. Climate reconstructions from this time period are thus essential. However, the number of Pliocene terrestrial climate reconstructions is extremely small. The major limitation is dating, which can often not provide the precision required to assign a climate record to the Pliocene, let alone reconstruct climate variability within the Pliocene.UoM hosts the world-leading institute in U-Pb dating of speleothems. With this method, speleothems with an age of four million years can be dated down to 1% precision. UoM has a large collection of Pliocene speleothems from the Nullarbor Plain in South Australia that require U-Pb dating. I would like to become acquainted with this method by applying it to these Pliocene speleothems and use them to reconstruct Pliocene climate. Arguably, there is no better place for this than UoM.Speleothem oxygen isotope records are among the most valuable records of climate change and may represent (among others) changes in rainfall amount, temperature, moisture source conditions and atmospheric circulation patterns. However, they rarely precipitate in isotope equilibrium. The degree of disequilibrium can be estimated by combining speleothem fluid inclusion isotope analysis and clumped isotopes. For the last two years, I analysed many speleothem samples for fluid inclusion isotopes, but I have no experience with clumped isotopes yet. UoM has an excellent clumped isotope facility, and I want to acquire in-depth knowledge such that I can establish this method when I return to Germany.Today the Nullarbor Plain is a desert, but a recent pollen study from Nullarbor speleothems has shown that the Pliocene was much wetter than today. However, it is unclear why, and which atmospheric circulation patterns dominated. I aim to combine clumped isotopes with fluid inclusion oxygen isotope analysis, generate a Pliocene oxygen isotope record and provide an interpretation in terms of temperature and atmospheric circulation patterns. The results of this project will provide a detailed look into our future climate and can be used to verify Pliocene climate model simulations.