Tropical stabilization of the thermohaline circulation in a greenhouse warming simulation

Most global climate models simulate a weakening of the North Atlantic therm ohaline circulation (THC) in response to enhanced greenhouse warming. Both surface warming and freshening in high latitudes, the so-called sinking reg ion, contribute to the weakening of the THC. Some models even simulate a co mplete breakdown of the THC at sufficiently strong forcing. Here results ar e presented from a state-of-the-art global climate model that does not simu late a weakening of the THC in response to greenhouse warming. Large-scale air-sea interactions in the Tropics, similar to those operating during pres ent-day El Ninos, lead to anomalously high salinities in the tropical Atlan tic. These are advected into the sinking region, thereby increasing the sur face density and compensating the effects of the local warming and fresheni ng.