The Start and the End of Our Interglacial.

• Main Authors: Berger, André, de Pablo, Elisabeth, Deslis, Jirasri, Fillon, Richard
• Other Authors: Université Catholique de Louvain = Catholic University of Louvain (UCL), Equipe Sémiotique Cognitive et Nouveaux Médias (ESCOM), Fondation Maison des sciences de l'homme (FMSH), Projet européen "DIVAS", ESCoM-AAR et projet européen DIVAS, European Project: 34376,DIVAS
• Format: Other/Unknown Material
• Language: English
• Published: HAL CCSD 2008
• Subjects: Holocene; Marine isotope stage 5; Paleoclimatology; Marine isotopic Stage 11; Ruddiman (2003); Greenhouse gas; CO2 concentration in the atmosphere; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDV.EE.BIO]Life Sciences [q-bio]/Ecology; environment/Bioclimatology; [SHS.ECO]Humanities and Social Sciences/Economics and Finance; [SDV.SA.AEP]Life Sciences [q-bio]/Agricultural sciences/Agriculture; economy and politics; EPICA; ice core; Loutre
• Online Access: https://hal.campus-aar.fr/medihal-01918249; https://hal.campus-aar.fr/medihal-01918249/document; https://hal.campus-aar.fr/medihal-01918249/file/509_2_berger-LAN_720p.mp4

Fonds audiovisuel du programme "ESCoM-AAR" (Equipe Sémiotique Cognitive et nouveaux Médias - Archives Audiovisuelles de la Recherche. Paris, France, 2000 - 2016). The previous interglacial (Marine isotope stage 5e, peaking at 125 kyr BP) is usually assumed to be a good analogue for our present-day climate. Moreover, as our present interglacial, the Holocene, is already almost 12 kyr long, paleoclimatologists were inclined to predict a quite close entrance into the next ice age. Simulations using the 2.5-D climate model of Louvain-la- Neuve show however that our interglacial will most probably last much longer than any previous one, even without human intervention (Berger and Loutre, 2002). It was suggested that this is related to the shape of the Earth’s orbit around the Sun which will be almost circular over the next tens of thousands of years. A circular orbit means indeed that the latitudinal and seasonal distributions of the energy received from the Sun will not vary anymore, a situation which will give more weight to the other forcings, in particular to the forcing by the greenhouse gases. As the eccentricity variation is primarily related to the 400-kyr cycle, the best and closer analogue for such a forcing is definitively Marine isotopic Stage 11 (MIS-11) some 400 kyr ago and not MIS-5e. Simulations of this MIS-11 interglacial under greenhouse gas and astronomical forcings led indeed also to an anomalous length, a prediction which was later confirmed by the EPICA ice-core record. Such a relationship between CO2 and climate is at the basis of the claim by Ruddiman (2003) that the impact of human activities on climate might have already started 10,000 years ago, preventing our climate to have already entered into glaciation. Sensitivity experiments with the LLN model tend to rule out Ruddiman’s hypothesis because glacial inception in this model would require CO2 concentration below 240 ppmv during the Holocene. However, honest estimates of model uncertainties incline us to leave the question open ...