Solar forced dansgaardoeschger events and their phase relation with solar proxies

North Atlantic climate during glacial times was characterized by large-amplitude switchings, the Dansgaard-Oeschger (DO) events, with an apparent tendency to recur preferably in multiples of about 1470 years. Recent work interpreted these intervals as resulting from a subharmonic response of a highly nonlin-ear system to quasi-periodic solar forcing plus noise. This hypothesis was chal-lenged as inconsistent with the observed variability in the phase relation be-tween proxies of solar activity and Greenland climate. Here we reject the claim of inconsistency by showing that this phase variability is a robust, generic feature of the nonlinear dynamics of DO events, as described by a model. This variability is expected from the fact that the events are threshold cross-ing events, resulting from a cooperative process between the periodic forc-ing and the noise. This process produces a fluctuating phase relation with the periodic forcing, consistent with proxies of solar activity and Greenland climate