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Abstract

During the Quaternary, the Hudson Bay switched between closed (covered by ice sheet) and open (ice sheet-free) conditions due to large variations of ice sheets. However, how the closure and opening of the Hudson Bay have affected the local and global climates is still poorly understood. Using the LOVECLIM1.3 model, here we investigate the effect of the Hudson Bay closure under glacial conditions with different astronomical configurations, greenhouse gases (GHG) concentrations and Northern Hemisphere (NH) ice volume. Our model results show that the closure of the Hudson Bay could lead to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC), which in turn leads to a warming in the NH with notable warming in the Labrador Sea and northeast North Atlantic, a cooling in the Southern Hemisphere (SH) and a northward shift of the Inter-tropical Convergence Zone (ITCZ). In addition to the large-scale climate changes, the closure of Hudson Bay also leads to a strong cooling over the Hudson Bay region due to changes of surface properties and a cooling to the southeast of Greenland due to more wind-driven sea ice export from the Arctic. However, the effect of the Hudson Bay closure depends on background climate conditions, and it could weaken or slightly reinforce the effect of the ice sheets for different astronomical configurations.