Did rising oceans force Vikings to leave Greenland?

A Harvard study reveals that settlers were up against forces they could not possibly overcome.

Around 980AD, a group of Vikings from Iceland started to settle in Southern Greenland. The migrating Norsemen benefitted from the warm Medieval period that left oceans relatively ice-free, with weather that allowed them to build homes, farm the land, and breed animals on the world's biggest island. In Greenland’s north the settlers even hunted walruses, selling their tusks to merchants in Europe, where the ivory was in high demand.

But around 1450, the seafarers suddenly disappeared from their settlements in the North Atlantic. Neither written sources nor verbal tradition explains precisely why.

Now a study carried out by scientists from the US Harvard University provides some of the possible answers.

In the study, which was published in the Proceedings of the National Academy of Sciences, the scientists focused on a Viking settlement that included 500 farms located on the southern tip of the island. The farms were built some 4km apart and not far from the edge of the Greenland ice sheet which covers most of the island.

The disappearance of the Vikings coincided with a period during which large parts of the Northern Hemisphere experienced a minor glacial period. This had particularly severe implications in the North Atlantic, and computer simulations have previously demonstrated growing ice masses along the coast of Greenland which probably forced the fertile coastal areas several metres below the ocean surface, reducing the opportunities for Greenland Norse to farm the land.

But that was not the only challenge. In the Harvard University study, the scientists took a more detailed look at the implications of the growing ice mass for the Greenland coast and its inhabitants. Their calculations and models reveal that the growing ice mass probably also exercised an increasing gravity effect on the waters around Greenland, causing a sea level rise of no less than 3.3 metres.

So the ice masses both made the sea level rise and the landscape drift lower – a combination which probably caused the coastline to withdraw hundreds of metres, leaving 200km2 of land and many homes under water.

Previous research has already indicated that rising sea levels were probably a factor during the Viking period in Greenland, but the scientists behind the new study are the first to prove just how dramatic were the implications of the water masses.

This may have been the ‘final straw’ for the Greenland settlers, who included Erik the Red’s son, Leif the Lucky. They already faced many other challenges in the hostile landscape: lower temperatures making it harder to farm land, conflicts with Inuits, and falling demand for walrus ivory as elephant ivory reached Europe. But according to the scientists, the rising water and the loss of land were probably a key factor in the complete disappearance of Greenland Norsemen around 1450.