Don E Penman CD Standish Monica Doubrawa Tim J Bralower Marci M. Robinson Jean Self-Trail Robert P. Speijer Peter Stassen Gavin L Foster James C. Zachos Tali L. Babila 2022 <div id="abstracts"><div class="core-container"><div>The Paleocene-Eocene Thermal Maximum (PETM) is recognized by a major negative carbon isotope (δ¹³C) excursion (CIE) signifying an injection of isotopically light carbon into exogenic reservoirs, the mass, source, and tempo of which continue to be debated. Evidence of a transient precursor carbon release(s) has been identified in a few localities, although it remains equivocal whether there is a global signal. Here, we present foraminiferal δ¹³C records from a marine continental margin section, which reveal a 1.0 to 1.5‰ negative pre-onset excursion (POE), and concomitant rise in sea surface temperature of at least 2°C and a decline in ocean pH. The recovery of both δ¹³C and pH before the CIE onset and apparent absence of a POE in deep-sea records suggests a rapid (&lt; ocean mixing time scales) carbon release, followed by recovery driven by deep-sea mixing. Carbon released during the POE is therefore likely more similar to ongoing anthropogenic emissions in mass and rate than the main CIE.</div></div></div> application/pdf 10.1126/sciadv.abg1025 en Science Surface ocean warming and acidification driven by rapid carbon release precedes Paleocene-Eocene Thermal Maximum article