Evolution of mean ocean temperature in Marine Isotope Stage 4

<p>Deglaciations are characterized by relatively fast and near-synchronous changes in ice sheet volume, ocean temperature, and atmospheric greenhouse gas concentrations, but glacial inception occurs more gradually. Understanding the evolution of ice sheet, ocean, and atmosphere conditions from...

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Main Authors: S. Shackleton, J. A. Menking, E. Brook, C. Buizert, M. N. Dyonisius, V. V. Petrenko, D. Baggenstos, J. P. Severinghaus
Format: Article
Language:English
Published: Copernicus Publications 2021-10-01
Series:Climate of the Past
Online Access:https://cp.copernicus.org/articles/17/2273/2021/cp-17-2273-2021.pdf
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author S. Shackleton
S. Shackleton
J. A. Menking
E. Brook
C. Buizert
M. N. Dyonisius
M. N. Dyonisius
V. V. Petrenko
D. Baggenstos
J. P. Severinghaus
author_facet S. Shackleton
S. Shackleton
J. A. Menking
E. Brook
C. Buizert
M. N. Dyonisius
M. N. Dyonisius
V. V. Petrenko
D. Baggenstos
J. P. Severinghaus
author_sort S. Shackleton
collection DOAJ
description <p>Deglaciations are characterized by relatively fast and near-synchronous changes in ice sheet volume, ocean temperature, and atmospheric greenhouse gas concentrations, but glacial inception occurs more gradually. Understanding the evolution of ice sheet, ocean, and atmosphere conditions from interglacial to glacial maximum provides insight into the interplay of these components of the climate system. Using noble gas measurements in ancient ice samples, we reconstruct mean ocean temperature (MOT) from 74 to 59.7 ka, covering the Marine Isotope Stage (MIS) 5a–4 boundary, MIS 4, and part of the MIS 4–3 transition. Comparing this MOT reconstruction to previously published MOT reconstructions from the last and penultimate deglaciation, we find that the majority of the last interglacial–glacial ocean cooling must have occurred within MIS 5. MOT reached equally cold conditions in MIS 4 as in MIS 2 (<span class="inline-formula">−2.7</span> <span class="inline-formula">±</span> 0.3 <span class="inline-formula"><sup>∘</sup></span>C relative to the Holocene, <span class="inline-formula">−0.1</span> <span class="inline-formula">±</span> 0.3 <span class="inline-formula"><sup>∘</sup></span>C relative to MIS 2). Using a carbon cycle model to quantify the CO<span class="inline-formula"><sub>2</sub></span> solubility pump, we show that ocean cooling can explain most of the CO<span class="inline-formula"><sub>2</sub></span> drawdown (32 <span class="inline-formula">±</span> 4 of 40 ppm) across MIS 5. Comparing MOT to contemporaneous records of benthic <span class="inline-formula"><i>δ</i><sup>18</sup></span>O, we find that ocean cooling can also explain the majority of the <span class="inline-formula"><i>δ</i><sup>18</sup></span>O increase across MIS 5 (0.7 ‰ of 1.3 ‰). The timing of ocean warming and cooling in the record and the comparison to coeval Antarctic isotope data suggest an intimate link between ocean heat content, Southern Hemisphere high-latitude climate, and ocean circulation on orbital and millennial timescales.</p>
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spelling doaj.art-d11481853d1f4bbdbc4cd1631af426c02022-12-21T21:32:16ZengCopernicus PublicationsClimate of the Past1814-93241814-93322021-10-01172273228910.5194/cp-17-2273-2021Evolution of mean ocean temperature in Marine Isotope Stage 4S. Shackleton0S. Shackleton1J. A. Menking2E. Brook3C. Buizert4M. N. Dyonisius5M. N. Dyonisius6V. V. Petrenko7D. Baggenstos8J. P. Severinghaus9Scripps Institution of Oceanography, University of California, San Diego, La Jolla, 92093, USApresent address: Department of Geosciences, Princeton University, Princeton, 08544, USACollege of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, 97331, USACollege of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, 97331, USACollege of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, 97331, USADepartment of Earth and Environmental Sciences, University of Rochester, Rochester, 14627, USApresent address: Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, DenmarkDepartment of Earth and Environmental Sciences, University of Rochester, Rochester, 14627, USAClimate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, SwitzerlandScripps Institution of Oceanography, University of California, San Diego, La Jolla, 92093, USA<p>Deglaciations are characterized by relatively fast and near-synchronous changes in ice sheet volume, ocean temperature, and atmospheric greenhouse gas concentrations, but glacial inception occurs more gradually. Understanding the evolution of ice sheet, ocean, and atmosphere conditions from interglacial to glacial maximum provides insight into the interplay of these components of the climate system. Using noble gas measurements in ancient ice samples, we reconstruct mean ocean temperature (MOT) from 74 to 59.7 ka, covering the Marine Isotope Stage (MIS) 5a–4 boundary, MIS 4, and part of the MIS 4–3 transition. Comparing this MOT reconstruction to previously published MOT reconstructions from the last and penultimate deglaciation, we find that the majority of the last interglacial–glacial ocean cooling must have occurred within MIS 5. MOT reached equally cold conditions in MIS 4 as in MIS 2 (<span class="inline-formula">−2.7</span> <span class="inline-formula">±</span> 0.3 <span class="inline-formula"><sup>∘</sup></span>C relative to the Holocene, <span class="inline-formula">−0.1</span> <span class="inline-formula">±</span> 0.3 <span class="inline-formula"><sup>∘</sup></span>C relative to MIS 2). Using a carbon cycle model to quantify the CO<span class="inline-formula"><sub>2</sub></span> solubility pump, we show that ocean cooling can explain most of the CO<span class="inline-formula"><sub>2</sub></span> drawdown (32 <span class="inline-formula">±</span> 4 of 40 ppm) across MIS 5. Comparing MOT to contemporaneous records of benthic <span class="inline-formula"><i>δ</i><sup>18</sup></span>O, we find that ocean cooling can also explain the majority of the <span class="inline-formula"><i>δ</i><sup>18</sup></span>O increase across MIS 5 (0.7 ‰ of 1.3 ‰). The timing of ocean warming and cooling in the record and the comparison to coeval Antarctic isotope data suggest an intimate link between ocean heat content, Southern Hemisphere high-latitude climate, and ocean circulation on orbital and millennial timescales.</p>https://cp.copernicus.org/articles/17/2273/2021/cp-17-2273-2021.pdf
spellingShingle S. Shackleton
S. Shackleton
J. A. Menking
E. Brook
C. Buizert
M. N. Dyonisius
M. N. Dyonisius
V. V. Petrenko
D. Baggenstos
J. P. Severinghaus
Evolution of mean ocean temperature in Marine Isotope Stage 4
Climate of the Past
title Evolution of mean ocean temperature in Marine Isotope Stage 4
title_full Evolution of mean ocean temperature in Marine Isotope Stage 4
title_fullStr Evolution of mean ocean temperature in Marine Isotope Stage 4
title_full_unstemmed Evolution of mean ocean temperature in Marine Isotope Stage 4
title_short Evolution of mean ocean temperature in Marine Isotope Stage 4
title_sort evolution of mean ocean temperature in marine isotope stage 4
url https://cp.copernicus.org/articles/17/2273/2021/cp-17-2273-2021.pdf
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