Continuous sterane and phytane δ13C record reveals a substantial pCO2 decline since the mid-Miocene

Autor: Caitlyn R. Witkowski, Anna S. von der Heydt, Paul J. Valdes, Marcel T. J. van der Meer, Stefan Schouten, Jaap S. Sinninghe Damsté
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nature Communications, Vol 15, Iss 1, Pp 1-9 (2024)
Druh dokumentu: article
ISSN: 2041-1723
21484147
DOI: 10.1038/s41467-024-47676-9
Popis: Abstract Constraining the relationship between temperature and atmospheric concentrations of carbon dioxide (pCO2) is essential to model near-future climate. Here, we reconstruct pCO2 values over the past 15 million years (Myr), providing a series of analogues for possible near-future temperatures and pCO2, from a single continuous site (DSDP Site 467, California coast). We reconstruct pCO2 values using sterane and phytane, compounds that many phytoplankton produce and then become fossilised in sediment. From 15.0-0.3 Myr ago, our reconstructed pCO2 values steadily decline from 650 ± 150 to 280 ± 75 ppmv, mirroring global temperature decline. Using our new range of pCO2 values, we calculate average Earth system sensitivity and equilibrium climate sensitivity, resulting in 13.9 °C and 7.2 °C per doubling of pCO2, respectively. These values are significantly higher than IPCC global warming estimations, consistent or higher than some recent state-of-the-art climate models, and consistent with other proxy-based estimates.
Databáze: Directory of Open Access Journals
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