The large decrease in Lennox Island land area is not surprising as PEI is one of the provinces most at risk from sea level rise (SLR) due to climate change. The high risk PEI faces is outlined in a combined federal government Natural Resources Canada - British Columbia government report that looks at risks of sea level rise due to climate change across Canada.
The Province of P.E.I. has an ocean-influenced coastline of approximately 3,200 km. The coastline is deeply indented by tidal inlets, estuaries and salt marsh and generally alternates between headlands of steep sandstone bluffs and extensive sandy beaches. The coast of P.E.I. has been identified as one of the areas most sensitive to SLR in the entire country. Factors contributing to this sensitivity include soft sandstone bedrock, a sandy and dynamic shore zone which is sediment starved in places, low terrain behind the shore with significant flooding potential and documented high rates of shore retreat86.
Given that P.E.I. is the smallest Canadian province - the island is only 224 km long and between 6 km and 64 km wide - a significant proportion of the population lives on or near the coast.
The majority of the P.E.I. coastline has a high physical sensitivity to SLR. Parts of the North Shore of P.E.I. are rated highly sensitive because this coast is exposed to the open Gulf of St. Lawrence, with potential wave-generating fetches87 of several hundred kilometres. Decreased sea-ice cover in winter may increase the amount of open water fetch, creating larger waves superimposed on storm surges88. Although Charlottetown Harbour is largely protected from the Northumberland Strait and the Gulf of St. Lawrence, relative sea level is rising and storm-surge events are increasingly common.
http://www2.gov.bc.ca/assets/gov/environment/climate-change/policy-legis...