Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material
It is still an open question how equilibrium warming in response to increasing radiative forcing – the specific equilibrium climate sensitivity S – depends on background climate. We here present palaeodata-based evidence on the state dependency of S, by using CO2 proxy data together with a 3-D ice-s...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.855449 2023-05-15T16:40:52+02:00 Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material Köhler, Peter de Boer, Bas von der Heydt, Anna S Stap, Lennert Bastiaan van de Wal, Roderik S W 2015-12-01 application/zip, 79.1 kBytes https://doi.pangaea.de/10.1594/PANGAEA.855449 https://doi.org/10.1594/PANGAEA.855449 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.855449 https://doi.org/10.1594/PANGAEA.855449 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Köhler, Peter; de Boer, Bas; von der Heydt, Anna S; Stap, Lennert Bastiaan; van de Wal, Roderik S W (2015): On the state dependency of the equilibrium climate sensitivity during the last 5 million years. Climate of the Past, 11(12), 1801-1823, https://doi.org/10.5194/cp-11-1801-2015 Dataset 2015 ftpangaea https://doi.org/10.1594/PANGAEA.855449 https://doi.org/10.5194/cp-11-1801-2015 2023-01-20T09:06:34Z It is still an open question how equilibrium warming in response to increasing radiative forcing – the specific equilibrium climate sensitivity S – depends on background climate. We here present palaeodata-based evidence on the state dependency of S, by using CO2 proxy data together with a 3-D ice-sheet-model-based reconstruction of land ice albedo over the last 5 million years (Myr). We find that the land ice albedo forcing depends non-linearly on the background climate, while any non-linearity of CO2 radiative forcing depends on the CO2 data set used. This non-linearity has not, so far, been accounted for in similar approaches due to previously more simplistic approximations, in which land ice albedo radiative forcing was a linear function of sea level change. The latitudinal dependency of ice-sheet area changes is important for the non-linearity between land ice albedo and sea level. In our set-up, in which the radiative forcing of CO2 and of the land ice albedo (LI) is combined, we find a state dependence in the calculated specific equilibrium climate sensitivity, S[CO2,LI], for most of the Pleistocene (last 2.1 Myr). During Pleistocene intermediate glaciated climates and interglacial periods, S[CO2,LI] is on average ~ 45 % larger than during Pleistocene full glacial conditions. In the Pliocene part of our analysis (2.6–5 Myr BP) the CO2 data uncertainties prevent a well-supported calculation for S[CO2,LI], but our analysis suggests that during times without a large land ice area in the Northern Hemisphere (e.g. before 2.82 Myr BP), the specific equilibrium climate sensitivity, S[CO2,LI], was smaller than during interglacials of the Pleistocene. We thus find support for a previously proposed state change in the climate system with the widespread appearance of northern hemispheric ice sheets. This study points for the first time to a so far overlooked non-linearity in the land ice albedo radiative forcing, which is important for similar palaeodata-based approaches to calculate climate sensitivity. However, ... Dataset Ice Sheet PANGAEA - Data Publisher for Earth & Environmental Science |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
description |
It is still an open question how equilibrium warming in response to increasing radiative forcing – the specific equilibrium climate sensitivity S – depends on background climate. We here present palaeodata-based evidence on the state dependency of S, by using CO2 proxy data together with a 3-D ice-sheet-model-based reconstruction of land ice albedo over the last 5 million years (Myr). We find that the land ice albedo forcing depends non-linearly on the background climate, while any non-linearity of CO2 radiative forcing depends on the CO2 data set used. This non-linearity has not, so far, been accounted for in similar approaches due to previously more simplistic approximations, in which land ice albedo radiative forcing was a linear function of sea level change. The latitudinal dependency of ice-sheet area changes is important for the non-linearity between land ice albedo and sea level. In our set-up, in which the radiative forcing of CO2 and of the land ice albedo (LI) is combined, we find a state dependence in the calculated specific equilibrium climate sensitivity, S[CO2,LI], for most of the Pleistocene (last 2.1 Myr). During Pleistocene intermediate glaciated climates and interglacial periods, S[CO2,LI] is on average ~ 45 % larger than during Pleistocene full glacial conditions. In the Pliocene part of our analysis (2.6–5 Myr BP) the CO2 data uncertainties prevent a well-supported calculation for S[CO2,LI], but our analysis suggests that during times without a large land ice area in the Northern Hemisphere (e.g. before 2.82 Myr BP), the specific equilibrium climate sensitivity, S[CO2,LI], was smaller than during interglacials of the Pleistocene. We thus find support for a previously proposed state change in the climate system with the widespread appearance of northern hemispheric ice sheets. This study points for the first time to a so far overlooked non-linearity in the land ice albedo radiative forcing, which is important for similar palaeodata-based approaches to calculate climate sensitivity. However, ... |
format |
Dataset |
author |
Köhler, Peter de Boer, Bas von der Heydt, Anna S Stap, Lennert Bastiaan van de Wal, Roderik S W |
spellingShingle |
Köhler, Peter de Boer, Bas von der Heydt, Anna S Stap, Lennert Bastiaan van de Wal, Roderik S W Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
author_facet |
Köhler, Peter de Boer, Bas von der Heydt, Anna S Stap, Lennert Bastiaan van de Wal, Roderik S W |
author_sort |
Köhler, Peter |
title |
Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
title_short |
Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
title_full |
Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
title_fullStr |
Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
title_full_unstemmed |
Model-based changes in global annual mean surface temperature change (Delta T_g) and radiative forcing due to land ice albedo changes (Delta R_[LI]) over the last 5 Myr, supplementary material |
title_sort |
model-based changes in global annual mean surface temperature change (delta t_g) and radiative forcing due to land ice albedo changes (delta r_[li]) over the last 5 myr, supplementary material |
publisher |
PANGAEA |
publishDate |
2015 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.855449 https://doi.org/10.1594/PANGAEA.855449 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Supplement to: Köhler, Peter; de Boer, Bas; von der Heydt, Anna S; Stap, Lennert Bastiaan; van de Wal, Roderik S W (2015): On the state dependency of the equilibrium climate sensitivity during the last 5 million years. Climate of the Past, 11(12), 1801-1823, https://doi.org/10.5194/cp-11-1801-2015 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.855449 https://doi.org/10.1594/PANGAEA.855449 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.855449 https://doi.org/10.5194/cp-11-1801-2015 |
_version_ |
1766031286776889344 |