How fast did the ocean—atmosphere system run during the last deglaciation?

Oxygen isotope analyses performed on planktonic and benthic foraminifera in four deep sea cores show that during the last deglaciation, the meltwater isotopic signal propagated almost instantaneously in the whole North Atlantic and in less than one millennia in the Pacific and Indian deep waters. Simple box-model calculations show that this results primarily from a transitory increase, by a factor of 2 to 3, of the rate of thermohaline circulation at the beginning of the deglaciation. These results are in agreement with the ¹⁴C age differences between benthic and planktonic foraminifera measured by Accelerator Mass Spectrometry.