The Greenland spatial fingerprint of Dansgaard-Oeschger events in observations and models, 2018-2023

Pleistocene Ice Ages display abrupt Dansgaard-Oeschger (DO) climate oscillations that provide prime examples of Earth System tipping points – abrupt transition that may result in irreversible change. Greenland ice cores provide key records of DO climate variability, but gas-calibrated estimates of the temperature change magnitudes have been limited to central and northwest Greenland. We combine new and existing records of surface temperature, Oxygen-18 (18O), deuterium excess, and accumulation rates, to create a multi-proxy “fingerprint” of the DO impact on Greenland. We use a series of idealized simulations with such models to identify regions of the North Atlantic that are critical in explaining DO variability. In our experiments, wintertime sea-ice cover in the subpolar gyre is both a sufficient and a necessary condition to explain the DO impact on Greenland. This contrasts with the more common suggestion that the Nordic Seas are the nexus of DO activity.