Existence of an ice cap during the mid-Cretaceous period (120–90 Ma): an AGCM investigation

• Published in: Annals of Glaciology
• Main Authors: Ramstein, Gilles, Fluteau, Frédéric, Masson-Delmotte, Valérie
• Other Authors: Laboratoire de Modélisation du Climat et de l'Environnement (LMCE), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1997
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Annals of Glaciology; Ice cap; Ice Sheet
• Online Access: https://hal.science/hal-03011972; https://hal.science/hal-03011972/document; https://hal.science/hal-03011972/file/ag4.pdf; https://doi.org/10.3189/S0260305500014038

International audience Many questions remain concerning whether or not an ice cap existed during the mid-Cretaceous period (120–90 Ma). Other than data and observations from ice-rafted materials, atmospheric general circulation models (AGCMs) may be appropriate tools to investigate whether changes in atmospheric composition, land-sea distribution, or oceanic circulation (used as boundary conditions to constrain the model), provide the climatic conditions that enable ice caps to be formed.This study uses an AGCM developed by the Laboratoire de Météorologie Dynamique (LMD) to perform a set of numerical sensitivity experiments to investigate plate tectonics (land–sea distribution and orography), CO2 partial pressure in the atmosphere and changes in prescribed sea-surface temperatures. The main goals are to quantify the effect of each forcing factor on the increase of Northern Hemisphere high-latitude temperatures, and to investigate whether combining these factors produce temperatures that would allow the ice-sheet formation.