Viking History is changing

The discovery of burial ships known as the Salme ships in 2008 and 2010 near the village of Salme on the island of Saaremaa, Estonia is changing the timeline for the Viking Age. Both ships were used for ship burials around 700–750 CE in the Nordic Iron Age and contained the remains of 41 warriors killed in battle, as well as 6 dogs, 2 hunting hawks and numerous weapons and other artifacts.

This is earlier than the raid on Lindisfarne in 793 that is considered the beginning of the Viking Age.

There are many theories on why the Norse explorers, traders and warriors, the latter known  as Vikings, sailed most of the North Atlantic, reaching south as far as North Africa and east as far as Russia, and through the Mediterranean as far as Constantinople and the Middle East, acting as looters, traders, colonists and mercenaries.  Various theories have been put forth: demographic, economic, ideological, political, and technological.

A theory of this migration that has not been widely discussed is environmental. A significant change to the climate known as the Volcanic Winter of 536, well documented in other areas and cultures but not mentioned in the movements of the Norse.  Summer temperatures in 536 fell by as much as 2.5 °C (4.5 °F) below normal in Europe. The lingering impact of the volcanic winter of 536 was augmented in 539–540, when another volcanic eruption caused summer temperatures to decline as much as 2.7 °C (4.9 °F) below normal in Europe. There is evidence of still another volcanic eruption in 547 which would have extended the cooler period. The volcanic eruptions caused crop failures, famine, and millions of deaths and initiated the Late Antique Little Ice Age, which lasted from 536 to 560.

This would be devastating to the people living in northern Europe and would result in people looking for other sources of food and warmer climates as their crops failed.