Continuous sterane and phytane δ13C record reveals a substantial pCO2 decline since the mid-Miocene
Constraining the relationship between temperature and atmospheric concentrations of carbon dioxide ( p CO 2 ) is essential to model near-future climate. Here, we reconstruct p CO 2 values over the past 15 million years (Myr), providing a series of analogues for possible near-future temperatures and...
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Veröffentlicht in: | Nature communications 2024-06, Vol.15 (1), p.5192-9 |
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Sprache: | eng |
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Zusammenfassung: | Constraining the relationship between temperature and atmospheric concentrations of carbon dioxide (
p
CO
2
) is essential to model near-future climate. Here, we reconstruct
p
CO
2
values over the past 15 million years (Myr), providing a series of analogues for possible near-future temperatures and
p
CO
2
, from a single continuous site (DSDP Site 467, California coast). We reconstruct
p
CO
2
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
p
CO
2
values steadily decline from 650 ± 150 to 280 ± 75 ppmv, mirroring global temperature decline. Using our new range of
p
CO
2
values, we calculate average Earth system sensitivity and equilibrium climate sensitivity, resulting in 13.9 °C and 7.2 °C per doubling of
p
CO
2
, 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.
Molecular fossils from marine phytoplankton reveal a substantial decline in CO2 values over the past 15 million years and may support higher climate sensitivity than previously reported. |
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ISSN: | 2041-1723 2041-1723 |
DOI: | 10.1038/s41467-024-47676-9 |