The quandary of detecting the signature of climate change in Antarctica

• Published in: Nature Climate Change
• Main Authors: Casado, Mathieu, Hébert, Raphaël, Faranda, Davide, Landais, Amaelle
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Alfred Wegener Institute Potsdam, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), London Mathematical Laboratory, Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Quandary; Antarc*; Antarctica; ice core
• Online Access: https://cnrs.hal.science/hal-04202689; https://cnrs.hal.science/hal-04202689/document; https://cnrs.hal.science/hal-04202689/file/Manuscript_reducedwordcount_v1.pdf; https://doi.org/10.1038/s41558-023-01791-5

International audience Global warming driven by human activities is expected to be accentuated in Polar Regions compared to the global average, an effect called the polar amplification. Yet, for Antarctica, the amplitude of warming is still poorly constrained due to short weather observations and the large decadal climate variability. Using a compilation of 78 ice core records, we provide a high-resolution reconstruction of past temperatures over the last 1000 years for seven regions of Antarctica and direct evidence of Antarctic polar amplification at regional and continental scales. We also show that the amplitude of both natural and forced variability is not captured by the CMIP5 and 6 model ensemble members, part of which could be explained by the Southern Annular Mode (SAM). This shows that not considering feedback loops causing the polar amplification could lead to an underestimation of the magnitude of anthropogenic warming and its consequences in Antarctica.