Oxygen isotope measurements in Greenland ice demonstrate that a series of rapid warm-cold oscillations -called Dansgaard-Oeschger events- punctuated the last glaciation (Dansgard et al., 1993, doi:10.1038/364218a0). Here we present records of sea surface temperature from North Atlantic sediments spanning the past 90 kyr which contain a series of rapid temperature oscillations closely matching those in the ice-core record, confirming predictions that the ocean must bear the imprint of the Dansgaard–Oeschger events (Broecker et al., 1988, doi:10.1016/0033-5894(88)90082-8; 1990, doi:10.1029/PA005i004p00469). Moreover, we show that between 20 and 80 kyr ago, the shifts in ocean-atmosphere temperature are bundled into cooling cycles, lasting on average 10 to 15 kyr, with asymmetrical saw-tooth shapes. Each cycle culminated in an enormous discharge of icebergs into the North Atlantic (a 'Hein-rich event' (Bond et al., 1992, doi:10.1038/360245a0; Broecker et al., 1992, doi:10.1007/BF00193540), followed by an abrupt shift to a warmer climate. These cycles document a previously unrecognized link between ice sheet behaviour and ocean-atmosphere temperature changes. An important question that remains to be resolved is whether the cycles are driven by external factors, such as orbital forcing, or by inter-nal ice-sheet dynamics.

In30-101 Heinrich layer 4 at 0.8 m. V30-101 and V23-81 (2.1-3.93 m) AMS14C ages from analyses done at ETH-zürich for this work. V23-81 (1.545 - 1.985 m) from Broecker et al., 1988.

Supplement to: Bond, Gerard C; Broecker, Wallace S; Johnsen, Sigfús Jóhann; McManus, James; Labeyrie, Laurent D; Jouzel, Jean; Bonani, Georges (1993): Correlations between climate records from North Atlantic sediments and Greenland ice. Nature, 365(6442), 143-147