Hierarchy of abrupt transitions in the past climate

• Main Authors: Rousseau, Denis-Didier, Lucarini, Valerio, Bagniewski, Witold
• Other Authors: Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Université de Montpellier (UM)
• Format: Report
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDE.MCG]Environmental Sciences/Global Changes; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-03713538; https://hal.archives-ouvertes.fr/hal-03713538v2/document; https://hal.archives-ouvertes.fr/hal-03713538v2/file/Hierarchy_advances_ms_template.pdf

The Earth’s climate has experienced numerous critical transitions during its history. Such transitions are evidenced in high-resolution records covering different timescales. This suggests the possibility of identifying, ranking past critical transitions, which yields a more complex perspective on climatic history. Such a context allows defining dynamical climate landscapes with multi-scale features. To illustrate such a richer structure, we have analyzed 2 key high-resolution datasets: the CENOGRID marine compilation (past 66 Myr), and North Atlantic U1308 record (past 3.3 Myr). Our aim was to examine objectively the observed visual evidence of abrupt transitions and to identify among them, the key thresholds indicating regime changes that differentiate among major clusters of variability. This identification is discussed after comparison with major climate factors. A hierarchy in the observed thresholds is proposed through a domino-like succession of abrupt transitions, corresponding to as many bifurcations that shaped the Earth’s climate system over the past 66 Ma.