Climate of the next million years : which scenarios for the future?
While many studies focus on the impacts of anthropogenic greenhouse gas on climate on the timescale of the next century, very few have investigated the impacts on a longer timescale, from tens of millennia to a million years. However, due to the long lifetime of CO2 in Earth's surface reservoir...
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ftccsdartic:oai:HAL:tel-04047027v1 2023-06-11T04:06:54+02:00 Climate of the next million years : which scenarios for the future? Le climat du prochain million d'années : quels scénarios pour le futur ? Leloup, Gaëlle Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) Université Paris-Saclay Didier Paillard Didier Roche Christophe Dumas Aurélien Quiquet 2023-02-03 https://theses.hal.science/tel-04047027 https://theses.hal.science/tel-04047027/document https://theses.hal.science/tel-04047027/file/113585_LELOUP_2023_archivage.pdf en eng HAL CCSD NNT: 2023UPASJ001 tel-04047027 https://theses.hal.science/tel-04047027 https://theses.hal.science/tel-04047027/document https://theses.hal.science/tel-04047027/file/113585_LELOUP_2023_archivage.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-04047027 Climatology. Université Paris-Saclay, 2023. English. ⟨NNT : 2023UPASJ001⟩ Carbon cycle Ice sheets Climat Cycle du carbone Calottes de glace [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/doctoralThesis Theses 2023 ftccsdartic 2023-05-06T22:55:43Z While many studies focus on the impacts of anthropogenic greenhouse gas on climate on the timescale of the next century, very few have investigated the impacts on a longer timescale, from tens of millennia to a million years. However, due to the long lifetime of CO2 in Earth's surface reservoirs, current anthropogenic emissions are expected to impact the climate on a much longer timescale than the coming century.The objective of this thesis is to broaden the scope of existing studies on the climate of the next million years, by revisiting some of their classical hypotheses. Existing studies rarely consider a partial or total melt of the Antarctic ice sheet, and assume that atmospheric CO2 concentrations come back to pre-industrial levels after hundreds of thousands years, due to silicate weathering.In this study, we explore potential evolutions of the Antarctic ice sheet.More precisely, I have investigated the long term equilibrium of the Antarctic ice sheet under different CO2 levels, using the Earth System model of intermediate complexity iLOVECLIM, coupled to the GRISLI Antarctic ice sheet model, by first applying increasing CO2 levels until the Antarctic ice sheet retreats entirely, and then applying decreasing CO2 levels until the ice sheet regrows. Our results show that the ice sheet exhibits a strong hysteresis behavior. Due to the inclusion of the albedo-melt feedback in our setup, the transition between a glaciated Antarctic ice sheet and an ice-free Antarctic and conversely is more brutal than in previous studies not including this feedback. The CO2 threshold for both Antarctic glaciation and deglaciation varies with the orbital configuration.Additionally, I have developed a conceptual model for the geological carbon cycle that includes multiple equilibria in order to reproduce multi million year cycles in the d13C that are coherent with the data. These potential multiple equilibria in the carbon cycle could lead to a widely different atmospheric CO2 concentration evolution on long timescales, compared ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Ice Sheet Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic The Antarctic |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
Carbon cycle Ice sheets Climat Cycle du carbone Calottes de glace [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
Carbon cycle Ice sheets Climat Cycle du carbone Calottes de glace [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Leloup, Gaëlle Climate of the next million years : which scenarios for the future? |
topic_facet |
Carbon cycle Ice sheets Climat Cycle du carbone Calottes de glace [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
While many studies focus on the impacts of anthropogenic greenhouse gas on climate on the timescale of the next century, very few have investigated the impacts on a longer timescale, from tens of millennia to a million years. However, due to the long lifetime of CO2 in Earth's surface reservoirs, current anthropogenic emissions are expected to impact the climate on a much longer timescale than the coming century.The objective of this thesis is to broaden the scope of existing studies on the climate of the next million years, by revisiting some of their classical hypotheses. Existing studies rarely consider a partial or total melt of the Antarctic ice sheet, and assume that atmospheric CO2 concentrations come back to pre-industrial levels after hundreds of thousands years, due to silicate weathering.In this study, we explore potential evolutions of the Antarctic ice sheet.More precisely, I have investigated the long term equilibrium of the Antarctic ice sheet under different CO2 levels, using the Earth System model of intermediate complexity iLOVECLIM, coupled to the GRISLI Antarctic ice sheet model, by first applying increasing CO2 levels until the Antarctic ice sheet retreats entirely, and then applying decreasing CO2 levels until the ice sheet regrows. Our results show that the ice sheet exhibits a strong hysteresis behavior. Due to the inclusion of the albedo-melt feedback in our setup, the transition between a glaciated Antarctic ice sheet and an ice-free Antarctic and conversely is more brutal than in previous studies not including this feedback. The CO2 threshold for both Antarctic glaciation and deglaciation varies with the orbital configuration.Additionally, I have developed a conceptual model for the geological carbon cycle that includes multiple equilibria in order to reproduce multi million year cycles in the d13C that are coherent with the data. These potential multiple equilibria in the carbon cycle could lead to a widely different atmospheric CO2 concentration evolution on long timescales, compared ... |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) Université Paris-Saclay Didier Paillard Didier Roche Christophe Dumas Aurélien Quiquet |
format |
Doctoral or Postdoctoral Thesis |
author |
Leloup, Gaëlle |
author_facet |
Leloup, Gaëlle |
author_sort |
Leloup, Gaëlle |
title |
Climate of the next million years : which scenarios for the future? |
title_short |
Climate of the next million years : which scenarios for the future? |
title_full |
Climate of the next million years : which scenarios for the future? |
title_fullStr |
Climate of the next million years : which scenarios for the future? |
title_full_unstemmed |
Climate of the next million years : which scenarios for the future? |
title_sort |
climate of the next million years : which scenarios for the future? |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://theses.hal.science/tel-04047027 https://theses.hal.science/tel-04047027/document https://theses.hal.science/tel-04047027/file/113585_LELOUP_2023_archivage.pdf |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
https://theses.hal.science/tel-04047027 Climatology. Université Paris-Saclay, 2023. English. ⟨NNT : 2023UPASJ001⟩ |
op_relation |
NNT: 2023UPASJ001 tel-04047027 https://theses.hal.science/tel-04047027 https://theses.hal.science/tel-04047027/document https://theses.hal.science/tel-04047027/file/113585_LELOUP_2023_archivage.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1768379128662196224 |