First of all, it is important to distinguish land territory, strictly speaking, from maritime territory. A reference to the waters of the Arctic archipelago, including the waters of the Northwest Passage, is a reference to maritime territory.
While the Inuit can claim that they have occupied the land territory since time immemorial, they cannot establish a similar claim in the case of the maritime territory.
In my humble opinion, as I have written—and the Canadian government does not fully agree with my position on this matter—Canada cannot establish historic title to the waters of the Arctic archipelago. However, we can establish our sovereignty on the basis of customary international law as interpreted by the court in 1951. As I said earlier, I am confident about that claim.
Not only can we invoke the fact that we have occupied the land territory, but we can also point to the fact the Canada's Inuit have used certain waters as if they were land territory to fish, hunt seal, and so forth, and that they have done so since time immemorial.
I think Canada can follow Norway's lead and invoke these facts to consolidate, but not establish, its sovereignty. Establishing sovereignty over waters is more difficult than establishing sovereignty over land. The same three things must be proven.