Climate change could turn Nova Scotia into an island in the next 20 years if the dikes on the strip of land connecting Nova Scotia to New Brunswick aren't rebuilt to withstand rising sea levels, says the mayor of Amherst, N.S.

The marshes, known as the Chignecto Isthmus, were reclaimed for farming by the Acadians beginning in the late 1600s. Many of the dikes they built are still in use.

Amherst Mayor David Kogon. (Town of Amherst) "It's not a question of if the dikes will be breached, it's simply a question of when," Amherst Mayor David Kogon told CBC's Information Morning.

Kogon said recent projections show sea levels will rise to the point where the marshes are flooded "and Nova Scotia becomes an island" within the next 15 to 20 years. He said an up-to-date engineering study is required to determine which repairs are needed.

Kogon has outlined his concerns in a letter directed to the infrastructure ministers in Nova Scotia, New Brunswick and Ottawa, with a request to meet "as soon as possible" to discuss an action plan.

The mayor of Sackville, N.B., and the warden of Cumberland County, N.S., also signed the letter, which was dated Nov. 1, 2017. Kogon said they have yet to receive a reply.

Impact of flooding

This repair project is of national importance because flooding would cut off rail and road transportation between Nova Scotia and the rest of Canada, said Kogon.

In his letter, Kogon cited a 2016 study from Natural Resources Canada that estimated a flood would cause more than $50 million a day in lost commerce.

Although he wasn't able to estimate the cost of the repairs, Kogon said repairing the dikes would be a multi-million dollar project. He also said the work needs to be completed within the next five years.

"This is not an optional project," he added.

Bill Casey, the MP for Cumberland-Colchester. (Tom Hanson/Canadian Press)

Infrastructure money

Bill Casey, the MP for Cumberland-Colchester, said the federal government transferred responsibility of the dikes to the provinces in 1966.

Nevertheless, he said he didn't think the provinces could cover the costs of the repairs on their own and the federal government has to play a role.

Casey said federal infrastructure spending is one possible source of funding for the repairs.