Journal Article

Assessing the Duration of the Paleocene‐Eocene Thermal Maximum

Galeotti, Simone, Heslop, David, Roberts, Andrew P., Rohling, Eelco J., Piedrahita, Victor A., Florindo, Fabio, Li, Jinhua

2025

Overview

The Paleocene‐Eocene Thermal Maximum (PETM) was a climate/carbon cycle perturbation recognized in stable carbon isotope (δ13C) records with a negative carbon isotope excursion (CIE). The PETM CIE termination has been associated with a δ13C inflection with pre‐PETM‐like values referred to as the G point. However, the G point approach has produced variable PETM CIE duration estimates (∼120–230 kyr), which reflects a need to test its reliability. Here, we apply statistical analyses to existing δ13C records and reveal that the G point is sensitive to underlying δ13C uncertainties. We generate a probabilistic‐based CIE detection limit, which constrains the time range over which the PETM is detected in δ13C records. This protocol reveals a protracted CIE recovery (>145 kyr) that accounts for a 268.8+21.2/−20.5 kyr PETM CIE duration. Our new duration estimate exceeds previous values, which confirms the potential of extreme carbon cycle perturbations to cause long‐lasting carbon cycle disruptions. Plain Language Summary Ancient global warming events can be used to better understand future impacts of anthropogenic global warming; however, the extent to which a massive carbon cycle perturbation can disrupt the carbon cycle remains elusive. Here, we constrain the duration of the largest climate/carbon cycle perturbation of the last ∼65 Ma, the Paleocene‐Eocene Thermal Maximum (PETM). The PETM duration has been widely studied using its signature in stable carbon isotope (δ13C) records, a negative carbon isotope excursion (CIE). We find that the previous concept to estimate the PETM CIE duration using δ13C signals is not replicable. Therefore, we develop a statistical approach that accounts for the recognizable PETM CIE signal. This new concept reveals a 268.8+21.2/−20.5 kyr PETM CIE duration, which is longer than previous ∼120–230 kyr estimates and suggests that carbon cycle perturbations have protracted impacts on the natural carbon cycle. Key Points We produce a statistically defined detection limit for the carbon isotope excursion (CIE) of the Paleocene‐Eocene Thermal Maximum (PETM) Our protocol establishes the time range over which the PETM CIE is detected in stable carbon isotope (δ13C) records Statistical analyses reveal a longer (268.8+21.2/−20.5 kyr) PETM CIE duration than previous estimates (∼120–230 kyr)

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Anthropogenic factors / Carbon / Carbon 13 / Carbon cycle / carbon isotope excursion (CIE) / Carbon isotopes / Climate / Climate change / Duration / Eocene / Estimates / Global warming / Human influences / Palaeocene / Paleocene / Paleocene‐Eocene Thermal Maximum (PETM) / Perturbation / Perturbations / PETM CIE duration / Statistical analysis / Statistical methods / Statistics