Revisiting the Geographical Extent of Exceptional Warmth in the Early Paleogene Southern Ocean

Abstract

Periods of transient warming superimposed on sustained greenhouse climates during the Paleocene and Eocene (early Paleogene; ca. 66-34 Million years ago (Ma)) may be employed as potential analogs for current climate change and potential end-member climate states under unabated carbon emissions (Burke et al., 2018). A negative carbon isotope excursion (CIE), globally recorded in terrestrial and marine sediments, combined with ocean acidification (McInerney & Wing, 2011;Zachos et al., 2005) at the onset of the Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) shows the rapid input of thousands of petagrams of 13 C-depleted C to the exogenic carbon pool (Dickens et al., 1995), providing a geologic analog to present-day anthropogenic emissions. Several smaller events appear to have occurred in the late Paleocene and throughout the early Eocene (Cramer et al., 2003;Lauretano et al., 2015;Westerhold et al., 2020) although their climatic expression remains unknown.In recent years, fully coupled climate models have been able to broadly reproduce sea-surface and air temperature proxy data for the warmest periods of the Cenozoic (