IRFP: GENIE Modeling of Paleogene Hyperthermals

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The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program?s awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise, and experimental conditions abroad. This award will support a twenty-four month research fellowship by Dr. Sandra Kirtland Turner to work with Dr. Andy Ridgwell at the University of Bristol in Bristol, United Kingdom.By the end of the 21st century, the continued build-up of greenhouse gases in the atmosphere means that radiative forcing of Earth's climate will surpass anything seen on Earth for tens of millions of years. Numerous abrupt warming events (hyperthermals) that occurred in the warm, 'greenhouse' climate before ~40 Ma provide our best analogs for future climate change. During these events, there is evidence for rapid injections of massive amounts of carbon into the oceans and atmosphere, accompanied by intense warming and ocean acidification. Characteristics of these events, including their regular occurrence and fast rate of recovery, suggest gaps in understanding of carbon cycle instabilities and feedbacks in a warm climate. To fully exploit the potential of these events to inform Earth's predicted long-term response to fossil fuel emissions, it is critical to combine datasets that reconstruct these events with models that test hypotheses regarding the controls on their occurrence. This research uses an Earth system model of intermediate complexity called GENIE (Grid-Enabled Integrated Earth system model) to test key questions regarding the mechanisms responsible for initiating and terminating hyperthermal events on a greenhouse Earth. The first objective is to use the GENIE model to assess the fidelity of individual paleoclimatic records in recording abrupt climate transitions. This exercise involves the development of a methodology to improve estimates of the size of these events by incorporating and systematically assessing the biases that influence preservation of event size and shape in the geologic record. The second objective is to add key model capabilities to GENIE that will 1) enable study of how variations in Earth's orbit impact the timing and size of hyperthermal events and 2) test the role of carbon sources that are not yet explicitly included in existing carbon cycle-climate models. In addition to her research, Dr. Kirtland Turner is interested in the broader social and political implications of paleoclimatology and carbon cycle-climate modeling. She hopes to use results from her reconstruction and modeling of hyperthermal events to educate the public and policymakers about the true lifetime of fossil fuel CO2 emissions and characteristics of a warm world. Finally, this research will help develop new international collaborations between the PI, collaborators at Scripps Institution of Oceanography in La Jolla, CA (Dr. Richard Norris? research group), and Dr. Ridgwell?s research group at the University of Bristol, U.K.