Up in smoke! Terrestrial carbon cycle feedbacks during warm climates

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Organic carbon preserved within sedimentary rocks (fossil OC) is a major carbon reservoir and plays a crucial role in the long-term evolution of atmospheric CO2 and O2, and thus global climate. The oxidation of fossil OC during uplift, exhumation and erosion has the potential to become an important source of CO2 to the atmosphere through positive climate feedbacks. However, the importance of fossil OC oxidation in future warm climates remains a major gap in our understanding.One way to test the behaviour of the Earth in warmer-than-present climate states is to examine the geological record. The Paleocene/Eocene Thermal Maximum (PETM) is the most rapid warming event in recent geologic history and is an analog for future climate change. Tantalizing evidence from this interval suggests that fossil OC oxidation may act as a positive feedback. However, this has yet to be globally confirmed. The aim of this project is to use a multi-proxy approach to test whether warm climates are associated with enhanced erosion, mobilization and oxidation of fossil OC and to determine whether this mechanism might act as a large source of atmospheric CO2.