Atmospheric CO2 during the Mid- Piacenzian Warm Period and the M2 glaciation
Atmospheric CO2 during the Mid- Piacenzian Warm Period and the M2 glaciation
The Piacenzian stage of the Pliocene (2.6 to 3.6 Ma) is the most recent past interval of sustained global warmth with mean global temperatures markedly higher (by ~2–3 °C) than today. Quantifying CO2 levels during the mid-Piacenzian Warm Period (mPWP) provides a means, therefore, to deepen our understanding of Earth System behaviour in a warm climate state. Here we present a new high-resolution record of atmospheric CO2 using the δ11B-pH proxy from 3.35 to 3.15 million years ago (Ma) at a temporal resolution of 1 sample per 3–6 thousand years (kyrs). Our study interval covers both the coolest marine isotope stage of the mPWP, M2 (~3.3 Ma) and the transition into its warmest phase including interglacial KM5c (centered on ~3.205 Ma) which has a similar orbital configuration to present. We find that CO2 ranged from 389+38−8ppm to 331+13−11,ppm, with CO2 during the KM5c interglacial being 371+32−29ppm (at 95% confidence). Our findings corroborate the idea that changes in atmospheric CO2 levels played a distinct role in climate variability during the mPWP. They also facilitate ongoing data-model comparisons and suggest that, at present rates of human emissions, there will be more CO2 in Earth’s atmosphere by 2025 than at any time in at least the last 3.3 million years.
De La Vega, Elwyn
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Chalk, Thomas B.
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Wilson, Paul A.
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Bysani, Ratna Priya
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Foster, Gavin L.
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1 December 2020
De La Vega, Elwyn
9606fbdd-1c10-4a13-956b-434f58a37b0b
Chalk, Thomas B.
42986a9c-7f97-4ae0-8d1d-4497035ce1e1
Wilson, Paul A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Bysani, Ratna Priya
b7ca549c-f884-4fa7-88e8-290446bdb0e7
Foster, Gavin L.
1ebee277-21b6-4ae3-9aa0-38c5ca49c762
De La Vega, Elwyn, Chalk, Thomas B., Wilson, Paul A., Bysani, Ratna Priya and Foster, Gavin L.
(2020)
Atmospheric CO2 during the Mid- Piacenzian Warm Period and the M2 glaciation.
Scientific Reports, 10 (1), [11002].
(doi:10.1038/s41598-020-67154-8).
Abstract
The Piacenzian stage of the Pliocene (2.6 to 3.6 Ma) is the most recent past interval of sustained global warmth with mean global temperatures markedly higher (by ~2–3 °C) than today. Quantifying CO2 levels during the mid-Piacenzian Warm Period (mPWP) provides a means, therefore, to deepen our understanding of Earth System behaviour in a warm climate state. Here we present a new high-resolution record of atmospheric CO2 using the δ11B-pH proxy from 3.35 to 3.15 million years ago (Ma) at a temporal resolution of 1 sample per 3–6 thousand years (kyrs). Our study interval covers both the coolest marine isotope stage of the mPWP, M2 (~3.3 Ma) and the transition into its warmest phase including interglacial KM5c (centered on ~3.205 Ma) which has a similar orbital configuration to present. We find that CO2 ranged from 389+38−8ppm to 331+13−11,ppm, with CO2 during the KM5c interglacial being 371+32−29ppm (at 95% confidence). Our findings corroborate the idea that changes in atmospheric CO2 levels played a distinct role in climate variability during the mPWP. They also facilitate ongoing data-model comparisons and suggest that, at present rates of human emissions, there will be more CO2 in Earth’s atmosphere by 2025 than at any time in at least the last 3.3 million years.
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Atmospheric co2 during the Mid-piacenzian Warm period
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e-pub ahead of print date: 9 July 2020
Published date: 1 December 2020
Additional Information:
Funding Information:
This research was supported by the National Environmental Research Council grant NE/H006273/1 and Royal Society Wolfson Merit awards to P. A. W. and G. L. F. We thank J. Andy Milton for plasma mass spectrometry support, Agnes Michalik and Matthew Cooper for clean laboratory assistance, and Megan Spencer and Bastian Hambach for support in stable isotope analysis.
Publisher Copyright:
© 2020, The Author(s).
Identifiers
Local EPrints ID: 444151
URI: http://eprints.soton.ac.uk/id/eprint/444151
ISSN: 2045-2322
PURE UUID: f2b8bac0-d55f-489a-a21b-6d55ee427914
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Date deposited: 29 Sep 2020 17:33
Last modified: 23 Jul 2022 01:46
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Contributors
Author:
Elwyn De La Vega
Author:
Thomas B. Chalk
Author:
Ratna Priya Bysani
Author:
Gavin L. Foster
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