Abstract Using outputs from eight Coupled Model Intercomparison Project Phase 6/Paleoclimate Model Intercomparison Project phase 4 models, we compare the hydrography and surface ocean circulation in the Arctic and sub‐Arctic regions across three climate states: the pre‐industrial (PI; 1850 CE), the Last Interglacial (LIG; 127 ka BP), driven by strong summer insolation in the high latitudes of the Northern Hemisphere, and an idealized future scenario forced by increasing atmospheric concentration. Insolation forcing at 127 ka causes an anomalous cyclonic circulation over Greenland and surrounding seas, which enhances the Baffin and Labrador currents, while slightly weakening the East Greenland Current relative to PI. These changes affect sea‐ice and water export on both sides of Greenland. Most models also simulate a strengthened North Atlantic Subpolar Gyre (SPG) and increased volume transports through Fram Strait and Barents Sea Opening. However, this does not always correlate with a larger heat transport into the Arctic. In contrast, under increased forcing, the SPG weakens, but more heat is carried toward the Arctic compared with the PI and LIG simulations. Consequently, temperatures of the surface and subsurface waters are higher in the Eurasian Basin and sea‐ice decline in the Barents Sea is more pronounced in the idealized future experiment. These changes closely resemble the ongoing Arctic Atlantification, whereas evidence for a similar process in the LIG simulation is less clear.
Sicard et al. (Sun,) studied this question.