Middle Miocene climate instability associated with high-amplitude CO2 variability
The amplitude of climatic change, as recorded in the benthic oxygen isotope record, has varied throughout geological time. During the late Pleistocene, changes in the atmospheric concentration of carbon dioxide (CO2) are an important control on this amplitude of variability. The contribution of CO2...
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:64197 2023-05-15T13:38:47+02:00 Middle Miocene climate instability associated with high-amplitude CO2 variability Greenop, Rosanna Foster, Gavin L. Wilson, Paul A. Lear, Caroline H. 2014-09-30 application/pdf https://orca.cardiff.ac.uk/id/eprint/64197/ https://doi.org/10.1002/2014PA002653 https://orca.cardiff.ac.uk/id/eprint/64197/1/2014PA002653.pdf en eng American Geophysical Union (AGU) / Wiley https://orca.cardiff.ac.uk/id/eprint/64197/1/2014PA002653.pdf Greenop, Rosanna, Foster, Gavin L., Wilson, Paul A. and Lear, Caroline H. https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430 2014. Middle Miocene climate instability associated with high-amplitude CO2 variability. Paleoceanography 29 (9) , pp. 845-853. 10.1002/2014PA002653 https://doi.org/10.1002/2014PA002653 file https://orca.cardiff.ac.uk/64197/1/2014PA002653.pdf doi:10.1002/2014PA002653 cc_by CC-BY QE Geology Article PeerReviewed 2014 ftunivcardiff https://doi.org/10.1002/2014PA002653 2022-10-27T22:40:13Z The amplitude of climatic change, as recorded in the benthic oxygen isotope record, has varied throughout geological time. During the late Pleistocene, changes in the atmospheric concentration of carbon dioxide (CO2) are an important control on this amplitude of variability. The contribution of CO2 to climate variability during the pre-Quaternary however is unknown. Here we present a new boron isotope-based CO2 record for the transition into the middle Miocene Climatic Optimum (MCO) between 15.5 and 17 Myr that shows pronounced variability between 300 ppm and 500 ppm on a roughly 100 kyr time scale during the MCO. The CO2 changes reconstructed for the Miocene are ~2 times larger in absolute terms (300 to 500 ppm compared to 180 to 280 ppm) than those associated with the late Pleistocene and ~15% larger in terms of climate forcing. In contrast, however, variability in the contemporaneous benthic oxygen isotope record (at ~1‰) is approximately two thirds the amplitude of that seen during the late Pleistocene. These observations indicate a lower overall sensitivity to CO2 forcing for Miocene (Antarctic only) ice sheets than their late Pleistocene (Antarctic plus lower latitude northern hemisphere) counterparts. When our Miocene CO2 record is compared to the estimated changes in contemporaneous δ18Osw (ice volume), they point to the existence of two reservoirs of ice on Antarctica. One of these reservoirs appears stable, while a second reservoir shows a level of dynamism that contradicts the results of coupled climate-ice sheet model experiments given the CO2 concentrations that we reconstruct. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Cardiff University: ORCA (Online Research @ Cardiff) Antarctic Paleoceanography 29 9 845 853 |
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Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
topic |
QE Geology |
spellingShingle |
QE Geology Greenop, Rosanna Foster, Gavin L. Wilson, Paul A. Lear, Caroline H. Middle Miocene climate instability associated with high-amplitude CO2 variability |
topic_facet |
QE Geology |
description |
The amplitude of climatic change, as recorded in the benthic oxygen isotope record, has varied throughout geological time. During the late Pleistocene, changes in the atmospheric concentration of carbon dioxide (CO2) are an important control on this amplitude of variability. The contribution of CO2 to climate variability during the pre-Quaternary however is unknown. Here we present a new boron isotope-based CO2 record for the transition into the middle Miocene Climatic Optimum (MCO) between 15.5 and 17 Myr that shows pronounced variability between 300 ppm and 500 ppm on a roughly 100 kyr time scale during the MCO. The CO2 changes reconstructed for the Miocene are ~2 times larger in absolute terms (300 to 500 ppm compared to 180 to 280 ppm) than those associated with the late Pleistocene and ~15% larger in terms of climate forcing. In contrast, however, variability in the contemporaneous benthic oxygen isotope record (at ~1‰) is approximately two thirds the amplitude of that seen during the late Pleistocene. These observations indicate a lower overall sensitivity to CO2 forcing for Miocene (Antarctic only) ice sheets than their late Pleistocene (Antarctic plus lower latitude northern hemisphere) counterparts. When our Miocene CO2 record is compared to the estimated changes in contemporaneous δ18Osw (ice volume), they point to the existence of two reservoirs of ice on Antarctica. One of these reservoirs appears stable, while a second reservoir shows a level of dynamism that contradicts the results of coupled climate-ice sheet model experiments given the CO2 concentrations that we reconstruct. |
format |
Article in Journal/Newspaper |
author |
Greenop, Rosanna Foster, Gavin L. Wilson, Paul A. Lear, Caroline H. |
author_facet |
Greenop, Rosanna Foster, Gavin L. Wilson, Paul A. Lear, Caroline H. |
author_sort |
Greenop, Rosanna |
title |
Middle Miocene climate instability associated with high-amplitude CO2 variability |
title_short |
Middle Miocene climate instability associated with high-amplitude CO2 variability |
title_full |
Middle Miocene climate instability associated with high-amplitude CO2 variability |
title_fullStr |
Middle Miocene climate instability associated with high-amplitude CO2 variability |
title_full_unstemmed |
Middle Miocene climate instability associated with high-amplitude CO2 variability |
title_sort |
middle miocene climate instability associated with high-amplitude co2 variability |
publisher |
American Geophysical Union (AGU) / Wiley |
publishDate |
2014 |
url |
https://orca.cardiff.ac.uk/id/eprint/64197/ https://doi.org/10.1002/2014PA002653 https://orca.cardiff.ac.uk/id/eprint/64197/1/2014PA002653.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/64197/1/2014PA002653.pdf Greenop, Rosanna, Foster, Gavin L., Wilson, Paul A. and Lear, Caroline H. https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430 2014. Middle Miocene climate instability associated with high-amplitude CO2 variability. Paleoceanography 29 (9) , pp. 845-853. 10.1002/2014PA002653 https://doi.org/10.1002/2014PA002653 file https://orca.cardiff.ac.uk/64197/1/2014PA002653.pdf doi:10.1002/2014PA002653 |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/2014PA002653 |
container_title |
Paleoceanography |
container_volume |
29 |
container_issue |
9 |
container_start_page |
845 |
op_container_end_page |
853 |
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1766111120810049536 |