Carbon Sequestration of the Middle Miocene Sunda Shelf Facilitated Global Climate Change

Abstract

AbstractLong‐term organic carbon (OC) burial on continental shelves has been widely recognized for regulating atmospheric CO2 (pCO2) and the global climate. However, quantitatively assessing shelf OC burial's role and process in prominent climate transitions is challenging. Using 367 drilling sites, we evaluated the impact of OC burial on the Sunda Shelf, the world's largest tropical shelf, on the middle Miocene carbon perturbation and climate change. Comparing the Miocene Climatic Optimum (MCO) and the Middle Miocene Climate Transition (MMCT) results demonstrated that OC was buried faster during the MMCT with an increment of 0.07–0.14 × 103 GtC/Myr. This would cause an additional 34.77–69.16 ppm pCO2 sequestration, contributing at least one‐sixth of the global pCO2 reduction. We found OC burial regulated the long‐standing Monterey carbon isotope excursion via negative and positive feedbacks during the MCO and MMCT, respectively. Expanded terrestrial carbon reservoirs and enhanced burial efficiency were key steps in the latter positive feedback.