The 8.2 kyr BP event simulated by a global atmosphere-sea-ice-ocean model

Seven freshwater perturbation experiments were performed with a global atmosphere-sea-ice-ocean model to study the mechanism behind the 8.2 kyr BP Holocene cooling event. These experiments differed in initial state and duration of the applied freshwater pulse, while the amount of freshwater was kept constant (4.67x10(14) m(3)). One of the scenarios, with freshwater added to the Labrador Sea at a rate of 0.75 Sv during 20 years, resulted in weakening of the North Atlantic thermohaline circulation during 320 years and surface cooling varying from 1 to 5 degreesC over adjacent continents. This result is consistent with proxy data, suggesting that a meltwater-induced weakening of the thermohaline circulation caused the event. Moreover, our results indicate that the time-scale of the meltwater release and the initial state are important, as both have a strong effect on the magnitude and duration of the produced model response.