 They argue that Younger Dryas events might be an intrinsic feature of deglaciations that occur at the end of glacial periods.Analyses of stable isotopes from Greenland ice cores provide estimates for the start and end of the Younger Dryas.The analysis of Greenland Summit ice cores, as part of the Greenland Ice Sheet Project-2 and Greenland Icecore Project, estimated that the Younger Dryas started about 12,800 ice (calendar) years BP.