The increasing mass of the Greenland ice sheet caused local sea level to rise more than 3 metres after Vikings colonised Greenland, flooding many settlements and contributing to their abandonment of the place
By Michael Le Page
17 April 2023
The settlement of Qassiarsuk in Greenland was once probably the site of Brattahlid, the home of Viking Leif Erikson, whose statue watches over the area
Cindy Hopkins/Alamy
The sea level around Greenland rose more than 3.3 metres from AD 1000 to 1450, contributing to the woes of Viking settlers and to their eventual abandonment of the island, researchers have found.
In AD 985, Erik the Red established a colony in Greenland after being exiled from Iceland. At the time, the North Atlantic region was unusually warm – the so-called medieval warm period – but after a massive volcanic eruption in Indonesia in 1257, conditions became much colder for several centuries, a period known as the little ice age.
That led to the expansion of the Greenland ice sheet, say Marisa Borreggine at Harvard University and their colleagues, causing the land adjacent to the ice sheet to subside because of the increased weight. The bigger ice sheet also had a greater mass and so exerted a stronger gravitational pull on the waters around Greenland. These two factors had roughly equal effects on sea level there.
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The growth of the Greenland ice sheet reduced global sea level by 7 millimetres during this time as it locked away water, but due to other factors, there was a small overall rise on average across the world. All of this contributed to the 3.3-metre rise around Greenland.
It was already known that the sea rose in Greenland when Vikings lived there, but Borreggine’s team is the first to calculate the effect. The findings show that the coast would have retreated hundreds of metres, with the water swamping more than 200 square kilometres of land and impinging on many farms and homes.