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

全球气候变化是人类今天面临的主要挑战之一。上新世时期（520万至260万年前）是最近的全球变暖事件，大气中的二氧化碳浓度相似。因此，它被广泛认为是21世纪末我们未来气候的模拟。因此，这一时期的气候重建至关重要。然而，上新世陆地气候重建的数量非常少。主要的限制是测年，它往往不能提供所需的精度来分配一个气候记录上新世，更不用说重建上新世内的气候变化.UoM主办的洞穴沉积物U-Pb测年的世界领先的研究所.使用这种方法，可以将400万年前的洞穴沉积物的年代确定到1%的精度。密歇根大学在南澳的纳拉伯平原收集了大量需要U-Pb测年的上新世洞穴沉积物。我想通过将这种方法应用于这些上新世洞穴沉积物来熟悉这种方法，并用它们来重建上新世气候。可以说，没有比密歇根大学更好的地方了。洞穴氧同位素记录是气候变化最有价值的记录之一，可能代表（除其他外）降雨量、温度、水分来源条件和大气环流模式的变化。然而，它们很少在同位素平衡中沉淀。不平衡程度可以通过洞穴流体包裹体同位素分析和聚集同位素分析相结合来估计。在过去的两年里，我分析了许多洞穴沉积物样品的流体包裹体同位素，但我还没有成团同位素的经验。密歇根大学有一个很好的同位素设备，我想获得深入的知识，这样我就可以建立这种方法，当我回到德国。今天的纳拉伯平原是一个沙漠，但最近对纳拉伯洞穴的花粉研究表明，上新世比今天潮湿得多。然而，目前还不清楚为什么，以及哪种大气环流模式占主导地位。我的目标是结合联合收割机成团同位素与流体包裹体氧同位素分析，产生上新世氧同位素记录，并提供解释的温度和大气环流模式。该项目的结果将提供对我们未来气候的详细了解，并可用于验证上新世气候模型模拟。

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.