Reconstructing Miocene warm climate dynamics from Indo-Pacific marine archives

The Miocene epoch offers the opportunity to investigate the sensitivity of the Earth's ocean-climate system to changes in radiative forcing, ice volume and the global carbon cycle on a warmer-than-modern Earth. The interval between 20 and 5 million years ago was marked by major climatic reversals and fundamental changes in terrestrial and marine ecosystems. However, the pace of change and the processes driving short- and long-term climate variability remain highly enigmatic. Recently, several IODP expeditions recovered exceptionally well-preserved sediment archives from the Pacific and Indian Oceans, which capture climate evolution in unprecedented resolution and offer a new view of Miocene warm climate dynamics. High-resolution isotope records of benthic foraminifers combined with paired isotope and Mg/Ca-derived temperature records of mixed layer foraminifers, carbonate accumulation estimates and XRF-scanning elemental data track the onset and development of the Miocene Climate Optimum (MCO, 16.9-14.7 Ma) and the transition to a glaciated mode with permanent ice cover on Antarctica. The MCO was characterized by "hyperthermal-style" variability with eccentricity-paced peak warmth episodes coinciding with extensive carbonate dissolution in the deep ocean. New patterns of variability emerged with stepwise global cooling and Antarctic glacial expansion following the end of the MCO. Our data show that changes in low latitude precipitation and weathering as well as marine biological productivity and carbon export flux in concert with reorganizations of the ocean-atmosphere circulation and cryosphere were instrumental in shaping Miocene climate evolution.