Sediments recovered at Ocean Drilling Program Site 984 on the Reykjanes Ridge provided multicentennial-scale records of late Pliocene climate change over the onset of Northern Hemisphere glaciation (NHG), 2.95--2.82 Ma. Short-term climate variations prior to and after the onset of continent-wide glaciation were compared to test the hypothesis of whether Dansgaard-Oeschger (DO) cycles may have been triggered by continental ice breakouts. During two selected interglacial stages prior to and after NHG (G15 and G1), climate variability resembled that found in the Holocene and the mid-Pliocene warm period. In contrast, DO-like periodicities of 1470, 2900, and 4400 years indeed only occurred in glacial stages after the onset of NHG (G14, G6, and 104) but not in stage G20 prior to the onset. These results suggest a causal link between DO cycles and the late Pliocene onset of major NHG and ice breakouts in the North Atlantic.