Abrupt glacial climate changes due to stochastic resonance.

Using an ocean-atmosphere climate model we demonstrate that stochastic resonance could be an important mechanism for millennial-scale climate variability during glacial times. We propose that the glacial ocean circulation, unlike today's, was an excitable system with a stable and a weakly unstable mode of operation, and that a combination of weak periodic forcing and plausible-amplitude stochastic fluctuations of the freshwater flux into the northern North Atlantic can produce glacial warm events similar in time evolution, amplitude, spatial pattern, and interspike intervals to those found in the observed climate records.