A record of $\delta^{18}$Oc from the Indian sector of Southern Ocean and atmospheric CO$_{2}$, and $\delta^{18}$O of European Project for Ice Coring in Antarctica (EPICA) and Greenland Ice Sheet Project 2 (GISP2) reveals that a coherent response between $\delta^{18}$O record of Antarctic ice core and the $\delta^{18}$Oc 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 CO$_{2}$ during same time. A distinct asynchrony between the records of $\delta^{18}$Oc from the Southern Indian Ocean and $\delta^{18}$O of GISP2 during the last deglaciation is noticed. We report that Southern Ocean degassing played an important role in raising atmospheric CO$_{2}$ through Atlantic Meridional Overturning Circulation (AMOC), which has an implication in triggering abrupt climate events through coupling of ocean and atmospheric processes.

$\bf{Highlights}$

$\bullet$ A synchrony between the temperature variations between the Antarctica and the southern sector of the Indian Ocean are noticed during the deglaciation.

$\bullet$ Initiation of deglacial warming in the southern sector of Indian Ocean started around 18 Ka which coincides with rise of atmospheric CO$_{2}$ during the same time.

$\bullet$ Degassing in the Southern Ocean played an important role in raising atmospheric CO$_{2}$ during the deglaciation.

$\bullet$ Changes in AMOC variations contributed to the trigger of CO$_{2}$ degassing from the deep Southern Ocean.