The Vikings may have had to abandon a prosperous colony because of rising sea levels.

The Vikings disappeared from Greenland in the mid-15th century, some 400 years after arriving there. Theories include drought, changing temperatures, social unrest, and the overhunting of walrus tusks. Now, a team of researchers from Harvard University and Pennsylvania State University have uncovered another key factor that could explain why the Vikings fled: a rise in sea levels. Using a computer model based on geological and climate records, the team found that sea levels would have risen by up to 3 meters (9.8 feet) during the four centuries of Norse occupation of the eastern settlement Vikings established in Greenland in 985 AD. This loss of habitable land would have been compounded by a trend from warmer temperatures towards cooler, drier temperatures in Europe that ultimately led to the Little Ice Age, which began around 1250 AD.

An analysis of human remains and animal remains from trash piles also showed that the diet of Viking settlers switched from land-based foods such as livestock to marine resources like fish and seals. The idea that sea levels would have been rising as temperatures fell is a little counterintuitive, as cool The study noted that changes in sea level don't affect all areas equally. The Norse settlement was located on the periphery of the Laurentide Ice Sheet and the Greenland Ice Sheet, which readvanced during Viking occupation and peaked in the Little Ice Age. This advance caused sea level rise near the ice margins due to the sinking of Earth’s crust. In a separate study, researchers found that Viking voyagers shipped timber across huge distances from North America and northern Europe because native trees in Greenland were unsuitable for shipbuilding and constructing large land-based projects. Microscopic analysis of timber remains, published in the journal Antiquity, showed that Norse Greenlanders had the means, knowledge and appropriate vessels to cross the North Atlantic to the east coast of North America, at least up until the 14th century.