Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability
Identifying and quantifying irreducible and reducible uncertainties in the Antarctic Ice Sheet response to future climate change is essential for guiding mitigation and adaptation policy decision. However, the impact of the irreducible internal climate variability, resulting from processes intrinsic...
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ftcopernicus:oai:publications.copernicus.org:egusphere117556 2024-09-15T17:42:21+00:00 Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability Caillet, Justine Jourdain, Nicolas C. Mathiot, Pierre Gillet-Chaulet, Fabien Urruty, Benoit Burgard, Clara Amory, Charles Kittel, Christoph Chekki, Mondher 2024-02-08 application/pdf https://doi.org/10.5194/egusphere-2024-128 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-128/ eng eng doi:10.5194/egusphere-2024-128 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-128/ eISSN: Text 2024 ftcopernicus https://doi.org/10.5194/egusphere-2024-128 2024-08-28T05:24:15Z Identifying and quantifying irreducible and reducible uncertainties in the Antarctic Ice Sheet response to future climate change is essential for guiding mitigation and adaptation policy decision. However, the impact of the irreducible internal climate variability, resulting from processes intrinsic to the climate system, remains poorly understood and quantified. Here, we characterise both the atmospheric and oceanic internal climate variability in a selection of three CMIP6 models (UKESM1-0-LL, IPSL-CM6A-LR and MPI-ESM1.2-HR) and estimate their impact on the Antarctic contribution to sea level over the 21 st century under the SSP2-4.5 scenario. To achieve this, we use a standalone ice-sheet model driven by the ocean through parameterised basal melting and by the atmosphere through emulated surface mass balance estimates. Internal climate variability affects the Antarctic contribution to changes in sea level until 2100 by 45 % to 93 % depending on the CMIP6 model. This may be a low estimate as the internal climate variability in the CMIP models is likely underestimated. For all the three climate models and for most Antarctic regions, the effect of atmospheric internal climate variability on the surface mass balance overwhelms the effect of oceanic internal climate variability on the dynamical ice-sheet mass loss by more than a factor of 3. The atmospheric internal climate variability is similar in the three CMIP6 models analysed in this study. Conversely, the amplitude of oceanic internal climate variability around Antarctica strongly depends on the climate model as underestimated convection, due to either biases in the sea-ice behaviour or in the ocean stratification, leads to weak mid-depth ocean variability. We then issue recommendations for future ice-sheet projections: use several members in the run and in its initialisation, favor 50-year averages to correct or weight simulations over the present-day period, and couple ice-sheet and climate models. Text Antarc* Antarctic Antarctica Ice Sheet Sea ice Copernicus Publications: E-Journals |
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Copernicus Publications: E-Journals |
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English |
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Identifying and quantifying irreducible and reducible uncertainties in the Antarctic Ice Sheet response to future climate change is essential for guiding mitigation and adaptation policy decision. However, the impact of the irreducible internal climate variability, resulting from processes intrinsic to the climate system, remains poorly understood and quantified. Here, we characterise both the atmospheric and oceanic internal climate variability in a selection of three CMIP6 models (UKESM1-0-LL, IPSL-CM6A-LR and MPI-ESM1.2-HR) and estimate their impact on the Antarctic contribution to sea level over the 21 st century under the SSP2-4.5 scenario. To achieve this, we use a standalone ice-sheet model driven by the ocean through parameterised basal melting and by the atmosphere through emulated surface mass balance estimates. Internal climate variability affects the Antarctic contribution to changes in sea level until 2100 by 45 % to 93 % depending on the CMIP6 model. This may be a low estimate as the internal climate variability in the CMIP models is likely underestimated. For all the three climate models and for most Antarctic regions, the effect of atmospheric internal climate variability on the surface mass balance overwhelms the effect of oceanic internal climate variability on the dynamical ice-sheet mass loss by more than a factor of 3. The atmospheric internal climate variability is similar in the three CMIP6 models analysed in this study. Conversely, the amplitude of oceanic internal climate variability around Antarctica strongly depends on the climate model as underestimated convection, due to either biases in the sea-ice behaviour or in the ocean stratification, leads to weak mid-depth ocean variability. We then issue recommendations for future ice-sheet projections: use several members in the run and in its initialisation, favor 50-year averages to correct or weight simulations over the present-day period, and couple ice-sheet and climate models. |
format |
Text |
author |
Caillet, Justine Jourdain, Nicolas C. Mathiot, Pierre Gillet-Chaulet, Fabien Urruty, Benoit Burgard, Clara Amory, Charles Kittel, Christoph Chekki, Mondher |
spellingShingle |
Caillet, Justine Jourdain, Nicolas C. Mathiot, Pierre Gillet-Chaulet, Fabien Urruty, Benoit Burgard, Clara Amory, Charles Kittel, Christoph Chekki, Mondher Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
author_facet |
Caillet, Justine Jourdain, Nicolas C. Mathiot, Pierre Gillet-Chaulet, Fabien Urruty, Benoit Burgard, Clara Amory, Charles Kittel, Christoph Chekki, Mondher |
author_sort |
Caillet, Justine |
title |
Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
title_short |
Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
title_full |
Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
title_fullStr |
Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
title_full_unstemmed |
Uncertainty in the projected Antarctic contribution to sea level due to internal climate variability |
title_sort |
uncertainty in the projected antarctic contribution to sea level due to internal climate variability |
publishDate |
2024 |
url |
https://doi.org/10.5194/egusphere-2024-128 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-128/ |
genre |
Antarc* Antarctic Antarctica Ice Sheet Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Sea ice |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2024-128 https://egusphere.copernicus.org/preprints/2024/egusphere-2024-128/ |
op_doi |
https://doi.org/10.5194/egusphere-2024-128 |
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1810488886826106880 |