Different trends in Antarctic temperature and atmospheric CO 2 during the last glacial

• Published in: Geophysical Research Letters
• Main Authors: Zheng, P, Pedro, JB, Jochum, M, Rasmussen, SO, Lai, Z
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2021
• Subjects: Earth Sciences; Physical geography and environmental geoscience; Palaeoclimatology; Antarctic; Greenland; Southern Ocean; Antarc*; ice core
• Online Access: https://doi.org/10.1029/2021GL093868; http://ecite.utas.edu.au/151696

We analyze the past 67,000years of climate using Antarctic ice-core records to constrain the mechanisms involved in (a) the bipolar seesaw relationship between Greenland and Antarctic surface temperature variations, and (b) mechanisms of millennial-scale atmospheric CO 2 concentration variations. Specifically, we determine for each Greenland Stadial the rate of Antarctic temperature and atmospheric CO 2 rise. We find that Antarctic warming rates significantly decrease as the climate cools during the glacial period, whereas the rate of atmospheric CO 2 rise does not significantly change. Also, we find that the rates of Antarctic warming and atmospheric CO 2 rise are both insensitive to whether a given stadial contains a Heinrich event. These results challenge the view that a single Southern-Ocean-based mechanism dominates the observed glacial variability in Antarctic temperature and atmospheric CO 2 . Instead, our results are consistent with an important contribution of low- and mid-latitude processes to millennial-scale atmospheric CO 2 changes.