Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects

One hundred thousand years of ice sheet buildup came to a rapid end ∼25–10 thousand years before present (ka BP), when ice sheets receded quickly and multi-proxy reconstructed global mean surface temperatures rose by ∼3–5 °C. It still remains unresolved whether insolation changes due to variations o...

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Published in:Climate of the Past
Main Authors: M. Heinemann, A. Timmermann, O. Elison Timm, F. Saito, A. Abe-Ouchi
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2014
Subjects:
geo
Online Access:https://doi.org/10.5194/cp-10-1567-2014
http://www.clim-past.net/10/1567/2014/cp-10-1567-2014.pdf
https://doaj.org/article/8fc93c0ef10a4e7aacd84a3f93a14eef
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spelling fttriple:oai:gotriple.eu:oai:doaj.org/article:8fc93c0ef10a4e7aacd84a3f93a14eef 2023-05-15T16:39:56+02:00 Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects M. Heinemann A. Timmermann O. Elison Timm F. Saito A. Abe-Ouchi 2014-08-01 https://doi.org/10.5194/cp-10-1567-2014 http://www.clim-past.net/10/1567/2014/cp-10-1567-2014.pdf https://doaj.org/article/8fc93c0ef10a4e7aacd84a3f93a14eef en eng Copernicus Publications 1814-9324 1814-9332 doi:10.5194/cp-10-1567-2014 http://www.clim-past.net/10/1567/2014/cp-10-1567-2014.pdf https://doaj.org/article/8fc93c0ef10a4e7aacd84a3f93a14eef undefined Climate of the Past, Vol 10, Iss 4, Pp 1567-1579 (2014) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2014 fttriple https://doi.org/10.5194/cp-10-1567-2014 2023-01-22T17:50:50Z One hundred thousand years of ice sheet buildup came to a rapid end ∼25–10 thousand years before present (ka BP), when ice sheets receded quickly and multi-proxy reconstructed global mean surface temperatures rose by ∼3–5 °C. It still remains unresolved whether insolation changes due to variations of earth's tilt and orbit were sufficient to terminate glacial conditions. Using a coupled three-dimensional climate–ice sheet model, we simulate the climate and Northern Hemisphere ice sheet evolution from 78 ka BP to 0 ka BP in good agreement with sea level and ice topography reconstructions. Based on this simulation and a series of deglacial sensitivity experiments with individually varying orbital parameters and prescribed CO2, we find that enhanced calving led to a slowdown of ice sheet growth as early as ∼8 ka prior to the Last Glacial Maximum (LGM). The glacial termination was then initiated by enhanced ablation due to increasing obliquity and precession, in agreement with the Milankovitch theory. However, our results also support the notion that the ∼100 ppmv rise of atmospheric CO2 after ∼18 ka BP was a key contributor to the deglaciation. Without it, the present-day ice volume would be comparable to that of the LGM and global mean temperatures would be about 3 °C lower than today. We further demonstrate that neither orbital forcing nor rising CO2 concentrations alone were sufficient to complete the deglaciation. Article in Journal/Newspaper Ice Sheet Unknown Climate of the Past 10 4 1567 1579
institution Open Polar
collection Unknown
op_collection_id fttriple
language English
topic geo
envir
spellingShingle geo
envir
M. Heinemann
A. Timmermann
O. Elison Timm
F. Saito
A. Abe-Ouchi
Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
topic_facet geo
envir
description One hundred thousand years of ice sheet buildup came to a rapid end ∼25–10 thousand years before present (ka BP), when ice sheets receded quickly and multi-proxy reconstructed global mean surface temperatures rose by ∼3–5 °C. It still remains unresolved whether insolation changes due to variations of earth's tilt and orbit were sufficient to terminate glacial conditions. Using a coupled three-dimensional climate–ice sheet model, we simulate the climate and Northern Hemisphere ice sheet evolution from 78 ka BP to 0 ka BP in good agreement with sea level and ice topography reconstructions. Based on this simulation and a series of deglacial sensitivity experiments with individually varying orbital parameters and prescribed CO2, we find that enhanced calving led to a slowdown of ice sheet growth as early as ∼8 ka prior to the Last Glacial Maximum (LGM). The glacial termination was then initiated by enhanced ablation due to increasing obliquity and precession, in agreement with the Milankovitch theory. However, our results also support the notion that the ∼100 ppmv rise of atmospheric CO2 after ∼18 ka BP was a key contributor to the deglaciation. Without it, the present-day ice volume would be comparable to that of the LGM and global mean temperatures would be about 3 °C lower than today. We further demonstrate that neither orbital forcing nor rising CO2 concentrations alone were sufficient to complete the deglaciation.
format Article in Journal/Newspaper
author M. Heinemann
A. Timmermann
O. Elison Timm
F. Saito
A. Abe-Ouchi
author_facet M. Heinemann
A. Timmermann
O. Elison Timm
F. Saito
A. Abe-Ouchi
author_sort M. Heinemann
title Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
title_short Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
title_full Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
title_fullStr Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
title_full_unstemmed Deglacial ice sheet meltdown: orbital pacemaking and CO2 effects
title_sort deglacial ice sheet meltdown: orbital pacemaking and co2 effects
publisher Copernicus Publications
publishDate 2014
url https://doi.org/10.5194/cp-10-1567-2014
http://www.clim-past.net/10/1567/2014/cp-10-1567-2014.pdf
https://doaj.org/article/8fc93c0ef10a4e7aacd84a3f93a14eef
genre Ice Sheet
genre_facet Ice Sheet
op_source Climate of the Past, Vol 10, Iss 4, Pp 1567-1579 (2014)
op_relation 1814-9324
1814-9332
doi:10.5194/cp-10-1567-2014
http://www.clim-past.net/10/1567/2014/cp-10-1567-2014.pdf
https://doaj.org/article/8fc93c0ef10a4e7aacd84a3f93a14eef
op_rights undefined
op_doi https://doi.org/10.5194/cp-10-1567-2014
container_title Climate of the Past
container_volume 10
container_issue 4
container_start_page 1567
op_container_end_page 1579
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