Role of the Bering Strait in the thermohaline circulation and abrupt climate change

Here we investigate the role of the Bering Strait (BS) in the thermohaline circulation (THC) response to added freshwater forcing (hosing) in the subpolar North Atlantic, through analyzing simulations of a fully coupled climate model with an open and closed BS. Results show that the THC declines similarly with an open and closed BS during hosing. However, the recovery of the THC is delayed by about a century in the closed BS simulation than in the open BS one after the hosing is off. The closed BS prevents the added freshwater being transported from the Atlantic into the Pacific via the Arctic as in the open BS case. Further, the freshwater supply is elevated significantly after the hosing by exporting the freshwater stored in the Arctic during hosing, as sea ice, back to the North Atlantic. This stabilizes the surface stratification there and suppresses the recovery of the deep convection.