A coherent response of Southern Indian Ocean to the Antarctic climate: Implications to the lead, lags of atmospheric CO2 during deglaciation.

A record of δ18Oc from the Indian sector of Southern Ocean and atmospheric CO2, and δ18O of European Project for Ice Coring in Antarctica (EPICA) and Greenland Ice Sheet Project 2 (GISP2) reveals that a coherent response between δ18O record of Antarctic ice core and the δ18Oc record from Southern Indian Ocean during the deglaciation with initial warming starting around 18 kyr BP which is in agreement with the raise of atmospheric CO2 during same time. A distinct asynchrony between the records of δ18Oc from the Southern Indian Ocean and δ18O of GISP2 during the last deglaciation is noticed. We report that Southern Ocean degassing played an important role in raising atmospheric CO2 through Atlantic Meridional Overturning Circulation (AMOC), which has an implication in triggering abrupt climate events through coupling of ocean and atmospheric processes. Highlights: A synchrony between the temperature variations between the Antarctica and the southern sector of the Indian Ocean are noticed during the deglaciation. Initiation of deglacial warming in the southern sector of Indian Ocean started around 18 Ka which coincides with rise of atmospheric CO2 during the same time. Degassing in the Southern Ocean played an important role in raising atmospheric CO2 during the deglaciation. Changes in AMOC variations contributed to the trigger of CO2 degassing from the deep Southern Ocean. [ABSTRACT FROM AUTHOR]