Detection of abrupt climate changes over the past 3.2 Myr

The past 3.2 Myr have seen drastic climate changes with the development, waxing and waning of huge continental ice sheets over the Northern Hemisphere. These striking phenomena have been observed in various records from ice cores, as well as marine and terrestrial sediments. These proxy records showed periodicities associated with the three orbital parameters that affect our planet's insolation, namely eccentricity, obliquity and precession. Until recently, these periodicities were considered as the canonical ones for the Quaternary Period and beyond. However, the improvement of the time resolution of available records has allowed one to describe climate changes occurring abruptly and with periodicities that are not related to those of the orbital parameters. The present datasets are those used to demonstrate that, in fact, these abrupt climate changes may still be related, albeit indirectly, to the astronomical theory of climate. They correspond to: 1- the statistics of the recurrence analysis of for North Atlantic core U1308 benthic δ18O representing the global temperature and the volume of continental ice sheet, U1308 bulk carbonate δ18O representing the ice-rafted debris released in the ocean(Hodell and Channell, 2016) covering the past 3.2 Myr and Greenland ice core NGRIP δ18O representing the temperature over Greenland (Rasmussen et al., 2014) covering the last 110 Kyr. These statistics correspond to changes in the variability regime present in the studied records with the identification of key transitions related to the variations in the Northern Hemisphere ice sheets; 2- the comparison of the main steps detected by Hodell and Channell (2016) from U1308 marine records with those deduced from the Recurrence Plot of the benthic δ18O and bulk carbonate δ18O data of the same record; 3-the thresholds identified in the recurrence plot of NGRIP δ18O record and their correspondence in the marine isotope stratigraphy of the last climate cycle stratigraphy from Bassinot et al., 1994 and Lisiecki and Raymo, 2005, showing a link between the length of the Greenland interstadials and the variations in the global sea level record.