The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next.

Climate proxy data from the NGRIP ice core, resampled to annual values on the GICC05 time scale. Periods covered: 11.55-11.85 ka BP (i.e. before A.D. 2000), 12.65-13.15 ka BP, and 14.55-14.85 ka BP. The dust content (particles/µl), Ca2+ (ppbw), and Na+ (ppbw) values are given as ln(value) as presented in the articles Figure 2. Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150

Supplement to: Steffensen, Jørgen Peder; Andersen, Katrine K; Bigler, Matthias; Clausen, Henrik Brink; Dahl-Jensen, Dorthe; Fischer, Hubertus; Goto-Azuma, Kumiko; Hansson, Margareta E; Johnsen, Sigfús Jóhann; Jouzel, Jean; Masson-Delmotte, Valerie; Popp, Trevor; Rasmussen, Sune Olander; Röthlisberger, Regine; Ruth, Urs; Stauffer, Bernhard; Siggaard-Andersen, Marie-Louise; Sveinbjörnsdottir, Árný E; Svensson, Anders M; White, James W C (2008): High-resolution Greenland ice core data show abrupt climate change happens in few years. Science, 321(5889), 680-684