Sensitivity of simulations of Plio-Pleistocene climate with the CLIMBER-2 Earth System Model to details of the global carbon cycle

• 成果类型: Article
• 署名作者: Carrillo, Judit; Mann, Michael E.; Marinov, Irina; Christiansen, Shannon A.; Willeit, Matteo; Ganopolski, Andrey
• 署名单位: University of Pennsylvania; Universidad de la Laguna; Potsdam Institut fur Klimafolgenforschung
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9191
• DOI: 10.1073/pnas.2427236122
• 发表日期: 2025-06-10
• 关键词: middle pleistocene transition; major glaciation cycles; ice-sheet evolution; milankovitch theory; aeolian dust; origin; temperature; DYNAMICS; dioxide; volume

摘要

The Earth system model CLIMBER-2 has been used in past work to successfully reproduce the glacial/interglacial cycles of the Plio-Pleistocene and the Mid-Pleistocene Transition (MPT) from predominantly 40 to 100 ky timescale oscillatory behavior as a function of declining volcanic outgassing and regolith removal. In this study, we further examine the sensitivity of this previous work to varying prescribed levels of volcanic outgassing and regolith extent and the long-term dynamics of the global carbon cycle, affecting the exchange and partitioning of carbon between different Earth system reservoirs and therefore global atmospheric CO2 concentrations. As volcanic outgassing decreases, CO2 and land carbon storage decrease, while ocean carbon storage, including CaCO3 sediment, increases. At volcanic outgassing levels below a threshold value of roughly 5.7 Tmol C yr-1, sea level decreases due to land ice formation, leading to increased carbon accumulation in the ocean and decreased carbon in the CaCO3 sediment reservoir. Our previous finding of strong hysteresis and path dependence in the glacial/interglacial alternation history [J. Carrillo et al., Proc. Natl. Acad. Sci. 121, e2322926121 (2024)] appears to be a tenuous climate feature, dependent on the precise representation of carbon cycle processes and, specifically, the numerical precision used in the calculation of certain key state variables in the model's carbon cycle.