Extended Data Fig. 8: Modelled global mean surface ocean carbon isotope excursion compared with high-resolution bulk carbonate carbon isotopic data from Hull et al.¹⁰.

Data shown were collected from Sites ODP 1209 (Shatsky Rise), ODP 1262 (Walvis Ridge), and IODP U1403 (J-Anomaly Ridge)¹⁰. The model shows reasonable agreement with proxy data, but we caution that the simulated ocean surface carbon isotope values during the 5 kyrs after the K-Pg boundary are ultimately subject to the total carbon emission and associated carbon isotope value set in the model. Brugger et al.²⁹ performed model sensitivity analysis to show that the total amount of 1615 Pg C matches the proxy record the best. Our value of 1750 Pg C generally agrees with Brugger et al.²⁹ but suggests a higher carbon emission is required to fully match the observation given the same carbon isotope signature. We did not conduct further sensitivity experiment as this is out of the scope of our study.