Research led by Dr. Jindong Jin from the Institute of Earth Environment, Chinese Academy of Sciences, in collaboration with multiple experts in China, utilized multi-proxy records from sediment at ODP Site 1090 in the South Ocean. By integrating published paleoclimate and paleoceanographic records, they conducted a climate comparative study on Marine Isotope Stages (MIS) 16 (676-621 thousand years ago) and MIS 12 (478-424 thousand years ago). The recent research findings have been published in Quaternary Science Reviews.
The team discovered that although MIS 12 and MIS 16 exhibited similar continental ice volumes, the northern hemisphere ice sheet during MIS 16 was larger compared to MIS 12, while the Antarctic ice sheet during MIS 12 was larger than MIS 16, reflecting the asymmetry of climate between the two hemispheres. In comparison to MIS 16, during MIS 12, the Southern Hemisphere westerlies weakened and shifted towards the equator, accompanied by the expansion of deep waters in the South Ocean and a tendency towards homogenization of deep ocean water masses. The higher atmospheric CO2 levels during MIS 12, relative to MIS 16, may be related to the ventilation of the two hemispheric oceans and the reorganization of deep water masses. The comprehensive differences in oceanic and climatic features during MIS 12 and MIS 16 revealed by this study provide a new perspective on carbon cycling and climate change on orbital time scales.
The study proposes a bipolar control mode of carbon cycling during Marine Isotope Stage 12 and Marine Isotope Stage 16. Image provided by the research team.
Related paper information: https://doi.org/10.1016/j.quascirev.2024.108721
