The Prehistory of  Greenland

Around 1000 B.C. major changes in site locations and use, house styles and artefact styles suggest that the life of the palaeo-Eskimo groups underwent important changes. In archaeological terms these changes are marked by shift from early Arctic Small Tool / early palaeo-Eskimo traditions to late Arctic Small Tool / late palaeo-Eskimo tradition or the Dorset culture.

The second major change in the human settling of the Eastern Arctic seems to have taken place around 1000 AD when Inuit groups from Alaska settled the entire area once peopled by the palaeo-Eskimo groups and became the direct ancestors of the present day Inuit.
Viking and Norse settlement in the North Atlantic and Greenland was an offshoot of the Scandinavian Viking Age in which Scandinavians came in close contacts with the rest of the world and new ideas and political and economical systems were introduced to the Scandinavian homelands.

The settlement in Greenland lasted for nearly 500 years and the depopulation coincided with climate changes in the northern hemisphere.