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Interesting:

Icelandic saga accounts of life in Greenland were composed in the 13th century and later, and do not constitute primary sources for the history of early Norse Greenland. Modern understanding therefore mostly depends on the physical data from archeological sites. Interpretation of ice core and clam shell data suggests that between 800 and 1300, the regions around the fjords of southern Greenland experienced a relatively mild climate several degrees Celsius higher than usual in the North Atlantic, with trees and herbaceous plants growing, and livestock being farmed. Barley was grown as a crop up to the 70th parallel. What is verifiable is that the ice cores indicate Greenland has had dramatic temperature shifts many times over the past 100,000 years. Similarly the Icelandic Book of Settlements records famines during the winters, in which “the old and helpless were killed and thrown over cliffs”.

One of the last contemporary written mentions of the Norse Greenlanders records a marriage which took place in 1408 in the church of Hvalsey—today the best-preserved Nordic ruins in Greenland.
These Icelandic settlements vanished during the 14th and early 15th centuries. The demise of the Western Settlement coincides with a decrease in summer and winter temperatures. A study of North Atlantic seasonal temperature variability during the Little Ice Age showed a significant decrease in maximum summer temperatures beginning in the late 13th century to early 14th century—as much as 6 to 8 °C (11 to 14 °F) lower than modern summer temperatures. The study also found that the lowest winter temperatures of the last 2000 years occurred in the late 14th century and early 15th century. The Eastern Settlement was likely abandoned in the early to mid-15th century, during this cold period.

https://en.wikipedia.org/wiki/Greenland#History