An expert in coastline erosion says the island of Newfoundland is sinking by a rate of about 3.5 millimetres a year.

Norm Catto, a Memorial University geography professor, has been using carbon dating on dead tree stumps preserved in calm ocean waters to determine when and how far water moved over land.

The carbon dating reveals the estimated time when salt water reached the tree sitting on land and killed its roots.

A researcher removes a tree stump at a beach in Mobile, on Newfoundland's Southern Shore, as part of research on how water has moved over the island. (Submitted by Norm Catto)

Catto said some of the stumps date back to 340 AD, the time of the Roman Empire, and they all tell the same story.

"If you've got a dock, or a piece of river or ocean property, then yes, the waves are getting closer to you every day," said Catto.

Change is small but important

Catto said although the rate at which Newfoundland is sinking only amounts to about 30 cm in 100 years, the change is important when serious storms hit the island.

"It means that the coastline is less equipped to resist storm activity or a surge when it actually does occur," said Catto.

Catto pointed out that parts of eastern Newfoundland's coastline were seriously damaged when Hurricane Igor swept through eastern Newfoundland in September 2010.

Catto said the water is rising at a faster rate on the southern part of the island than in the north, and the only part of Newfoundland and Labrador not showing a rise in water levels is at Lake Melville in Labrador.