I have no idea when the paper will be on PNAS's website, so I thought I would at least point to the ScienceDailyrelease, Climate Played Big Role in Vikings' Disappearance from Greenland:
Greenland's early Viking settlers were subjected to rapidly changing climate. Temperatures plunged several degrees in a span of decades, according to research from Brown University. A reconstruction of 5,600 years of climate history from lakes near the Norse settlement in western Greenland also shows how climate affected the Dorset and Saqqaq cultures.....
The Dorset were the non-European population which preceded the Inuit, and the Saqqaq preceded them. Last year Nature published a paper based on 350,000 SNPs from an ancient Saqqaq male which showed that he was related to modern Siberian peoples, and not to the later Inuit. That's at least a very clear argument for why we should be very cautious about extrapolating from the genetic patterns ...
