PICE talk by Peisong Zheng

(Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, China, & School of Earth Sciences, China University of Geosciences, Wuhan, China)

Title: Different trends in Antarctic temperature and atmospheric CO2 during the last glacial

Abstract: Glacial climate is characterized by millennial-scale variations in polar temperature and atmospheric CO2 concentration. The observed similarities between the shape of atmospheric CO2 and Antarctic temperature records, derived from Antarctic ice cores, have led to a common view that variations in both are dominated by a common Southern Ocean mechanism. However, a systematic comparison of the rates of change of Antarctic temperature and atmospheric CO2 during these millennia-scale events has not previously been conducted. Here, using ice-core data, we determine for each Greenland Stadial (The cold phase of the Dansgaard-Oeschger event) the rate of Antarctic temperature and atmospheric CO2 rise. We find that Antarctic warming rates significantly decrease as the climate cools during the glacial period, whereas the rate of atmospheric CO2 rise does not significantly change. Also, we find that the rates of Antarctic warming and atmospheric CO2 rise are both insensitive to whether a given stadial contains a Heinrich event (large-scale iceberg discharge into the North Atlantic). These results challenge the view that a single Southern-Ocean-based mechanism dominates the observed glacial variability in Antarctic temperature and atmospheric CO2. Instead, our results are consistent with an important contribution of low- and mid-latitude processes to millennial-scale atmospheric CO2 changes.

P. Zheng, J.B. Pedro, M. Jochum, S.O. Rasmussen, and Z. Lai,
Different trends in Antarctic temperature and atmospheric CO2 during the last glacial,
Geophysical Research Letters, 48, e2021GL093868, 2021,
https://doi.org/10.1029/2021GL093868

The talk will be broadcasted at PICE in room 202 with the zoom link: https://ucph-ku.zoom.us/j/64402633878