| Summary: | During the last glacial/interglacial transition the Earth’s climate underwent around 14.6 kyr ago rapid changes. Temperature proxies from ice cores revealed the onset of the Bølling/Allerød (B/A) warm period in the north (Steffensen et al. 2008) and the start of the Antarctic Cold Reversal in the south (Stenni et al. 2001). Further-more, the B/A is accompanied by a rapid sea level rise of about 20 m during melt-water pulse (MWP) 1A (Peltier & G.Fairbanks 2007), whose exact timing is matter of current debate (Hanebuth et al. 2000; Kienast et al. 2003; Stanford et al. 2006; Deschamps et al. 2009). In situ measured CO2 in the EPICA Dome C (EDC) ice core also revealed at the same time a remarkable jump of 10±1 ppmv in 230 years (Monnin et al. 2001; Lourantou et al. 2010). Allowing for the age distribution of CO2 in firn we here show, that atmospheric CO2 rose indeed by 20–35 ppmv in less than 200 years, which is a factor of 2–3.5 larger than the CO2 signal recorded in situ in the EDC. Based on the modelled fingerprint and δ13CO2 measured in EDC (Lourantou et al. 2010) we infer that 125 Pg of carbon of terrestrial origin need to be released to the atmosphere to produce such a peak. Most of the car-bon might have been activated as consequence of continental shelf flooding during MWP-1A. This impact of rapid sea level rise on atmospheric CO2 distinguishes the B/A from other Dansgaard/Oeschger (D/O) events, potentially defining the point of no return during the last deglaciation. Paleo Records during MIS 3 and Termination I
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