δ¹¹B-based atmospheric CO₂ records during the Pliocene at orbital resolution

The Mid-Pliocene is the most recent time in Earth's history when mean global temperatures were substantially warmer and sea levels higher than they are today. The subsequent intensification of the Northern Hemisphere Glaciation (iNHG) represents the key final step in the climatic transition from the warm Pliocene to the current “icehouse” climate. Recent modeling and proxy based results suggest that this climate shift was forced by a reduction in atmospheric CO2 concentrations (pCO2), which highlights the relationship between climate and this important greenhouse gas. Hence, there is significant potential in the use of the Pliocene as an analogue for future global warming in modeling studies and as a key period to study the role of CO2 in driving major climatic shifts. Despite recent advances in the reconstruction of pCO2 change during this important period, detail at the orbital scale is currently lacking. Boron isotopes in planktic foraminifera are a proven proxy for surface oceanic pH, which has been shown to provide valuable insights into past changes in the ocean carbonate system and ultimately into past atmospheric pCO2. Here we will provide foraminiferal δ11B-based records to determine the temporal evolution of pCO2 for an interval spanning the Pliocene Warm Period and the iNGH at orbital scale temporal resolution. Our record provides valuable insights into the causes and consequences of the changes in the atmospheric concentration of this important greenhouse gas