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Abstract: A new ice core chronology for the Greenland DYE-3, GRIP, and NGRIP ice cores has been constructed, making it possible to compare the and accumulation signals recorded in the three cores on an almost annual scale throughout the Holocene. We here introduce the new time scale and investigate and accumulation anomalies that are common to the three cores in the Early Holocene (7.9–11.7ka before present). Three time periods with significant and synchronous anomalies in the and accumulation signals stand out: the well-known 8.2ka event, an event of shorter duration but of almost similar amplitude around 9.3ka before present, and the Preboreal Oscillation during the first centuries of the Holocene. For each of these sections, we present a anomaly curve and a common accumulation signal that represents regional changes in the accumulation rate over the Greenland ice cap. [Copyright &y& Elsevier]

Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5°C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time. [ABSTRACT FROM AUTHOR]