Via Climate Feedback, there is a new letter in Nature that uses idealized freshening of the Atlantic MOC to initiate Dansgaard–Oeschger oscillations and does a reasonably good job reproducing the CO2 and N2O changes found in ice core samples.
Figure 2, ice-cores vs. model (Schmittner and Galbraith 2008)
The usual caveats about model simplicity apply. And of course, the initial trigger for the D-O seesawing remains unknown, although there are a few likely suspects. Interestingly, the single forcing (North Atlanitic freshwater) was able to more or less reproduce the divergent stories the two hemispheres tell about the same gases.
[UPDATE: here’s a link that isn’t money-walled.]