Assessing the Duration of the Paleocene-Eocene Thermal Maximum

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.