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CO2-driven ocean circulation changes as an amplifier of Paleocene-Eocene thermal maximum hydrate destabilization

CO2-driven ocean circulation changes as an amplifier of Paleocene-Eocene thermal maximum hydrate destabilization
CO2-driven ocean circulation changes as an amplifier of Paleocene-Eocene thermal maximum hydrate destabilization
Changes in ocean circulation have been proposed as a trigger mechanism for the large coupled climate and carbon cycle perturbations at the Paleocene-Eocene Thermal Maximum (PETM, ca. 55 Ma). An abrupt warming of oceanic intermediate waters could have initiated the thermal destabilization of sediment-hosted methane gas hydrates and potentially triggered sediment slumps and slides. In an ensemble of fully coupled atmosphere-ocean general circulation model (AOGCM) simulations of the late Paleocene and early Eocene, we identify such a circulation-driven enhanced intermediate-water warming. Critically, we find an approximate twofold amplification of Atlantic intermediate-water warming when CO2 levels are doubled from 2x to 4x preindustrial CO2 compared to when they are doubled from 1x to 2x. This warming is largely focused on the equatorial and South Atlantic and is driven by a significant reduction in deep-water formation from the Southern Ocean. This scenario is consistent with altered PETM circulation patterns inferred from benthic carbon isotope data and the intensity of deep-sea carbonate dissolution in the South Atlantic. The linkage between intermediate-water warming and gas hydrate destabilization could provide an important feedback in the establishment of peak PETM warmth.
0091-7613
875-878
Lunt, Daniel J.
931ecfb5-1f50-412c-8f01-a46d69b1f82f
Valdes, Paul J.
d4cdc123-544c-4df7-8c61-1781cf50f104
Jones, Tom Dunkley
5466097c-19e8-4173-9c6f-6727e64e0e34
Ridgwell, Andy
769cea5c-e033-456a-8b53-51dfa307dc35
Haywood, Alan M.
579a1e53-4e73-45fe-b8be-10724dcf65f0
Schmidt, Daniela N.
86a34245-7197-4ad2-984c-40374fe00b60
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Maslin, Mark
985a7cfc-98b0-44ae-b586-e17cf6dffe2e
Lunt, Daniel J.
931ecfb5-1f50-412c-8f01-a46d69b1f82f
Valdes, Paul J.
d4cdc123-544c-4df7-8c61-1781cf50f104
Jones, Tom Dunkley
5466097c-19e8-4173-9c6f-6727e64e0e34
Ridgwell, Andy
769cea5c-e033-456a-8b53-51dfa307dc35
Haywood, Alan M.
579a1e53-4e73-45fe-b8be-10724dcf65f0
Schmidt, Daniela N.
86a34245-7197-4ad2-984c-40374fe00b60
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Maslin, Mark
985a7cfc-98b0-44ae-b586-e17cf6dffe2e

Lunt, Daniel J., Valdes, Paul J., Jones, Tom Dunkley, Ridgwell, Andy, Haywood, Alan M., Schmidt, Daniela N., Marsh, Robert and Maslin, Mark (2010) CO2-driven ocean circulation changes as an amplifier of Paleocene-Eocene thermal maximum hydrate destabilization. Geology, 38 (10), 875-878. (doi:10.1130/G31184.1).

Record type: Article

Abstract

Changes in ocean circulation have been proposed as a trigger mechanism for the large coupled climate and carbon cycle perturbations at the Paleocene-Eocene Thermal Maximum (PETM, ca. 55 Ma). An abrupt warming of oceanic intermediate waters could have initiated the thermal destabilization of sediment-hosted methane gas hydrates and potentially triggered sediment slumps and slides. In an ensemble of fully coupled atmosphere-ocean general circulation model (AOGCM) simulations of the late Paleocene and early Eocene, we identify such a circulation-driven enhanced intermediate-water warming. Critically, we find an approximate twofold amplification of Atlantic intermediate-water warming when CO2 levels are doubled from 2x to 4x preindustrial CO2 compared to when they are doubled from 1x to 2x. This warming is largely focused on the equatorial and South Atlantic and is driven by a significant reduction in deep-water formation from the Southern Ocean. This scenario is consistent with altered PETM circulation patterns inferred from benthic carbon isotope data and the intensity of deep-sea carbonate dissolution in the South Atlantic. The linkage between intermediate-water warming and gas hydrate destabilization could provide an important feedback in the establishment of peak PETM warmth.

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Published date: October 2010
Organisations: Ocean and Earth Science

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Local EPrints ID: 167883
URI: http://eprints.soton.ac.uk/id/eprint/167883
ISSN: 0091-7613
PURE UUID: 48cd63e5-32a7-4281-a054-b1a5cea6197c

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Date deposited: 19 Nov 2010 16:06
Last modified: 14 Mar 2024 02:16

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Contributors

Author: Daniel J. Lunt
Author: Paul J. Valdes
Author: Tom Dunkley Jones
Author: Andy Ridgwell
Author: Alan M. Haywood
Author: Daniela N. Schmidt
Author: Robert Marsh
Author: Mark Maslin

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