I know ...
that you didn't come up with the 150 year figure but repeating it is still misleading. Did you check out the graph I cited? Notice that the Greenland surface melt events are concentrated in the period from 4,000 to 8,000 years ago and particularly from 6,000 to 8,000 years ago. Also not in the graph below the main one how much higher July insolation was back then.