Here goes one of the resident Navy type, which happens to have been a lawyer too!
And this is going down the rabbit hole because I know we've addressed this before, bu here goes:
There are all sorts of issues relating to Arctic sovereignty and Arctic ocean waters qualification.
The first thing to keep in mind is that the Arctic ocean (AO) is ... well an ocean. At approx. 14 millions square kilometres, it is about six times the size of the Mediterranean sea. The largest countries bordering that ocean, with almost all of the ocean's land borders between them, are Russia, Canada and the USA. The rest are a few European countries, but they don't amount to much land borders on the AO. Also, within those 14M Km2, there is something called the Canadian Arctic archipelago (CAA), which encompasses nearly 1.4M Km2. It is also an unusually shallow ocean, averaging about 1 Km depth of fairly even bottom (no Marianna trench up there that humans have found yet).
So: All the countries that border the AO are entitled to the usual internal waters (basically the river estuaries, the tidal area and some bays and inclusions subject to the use of baseline, then from there, the usual 12 NM territorial waters and the usual 200 NM Exclusive Economic Zone.
Everything else is international waters as for every other ocean. This means that, when the ocean opens up for navigation on its whole surface, it will be just like every other ocean: open to any country the world and nobody being able to claim anything particular about it (save for continental shelf rights - we will see later).
As far as land masses in the Arctic are concerned, there are, at this time, no international disputes or conflict, except for Hans Island between Canada and Denmark, and it's a pretty cold conflict (which is appropriate for the Arctic
). Otherwise, just about every nation recognizes the current claims to land sovereignty of Arctic nations.
There is, however, one special "animal" up there: The CAA. At about 10% of the AO area, it is unlike anything else out there (or in the world, really). While Russia and European countries have some Arctic Islands, even a few groupings of Islands scattered here and there North of their Northern mainland border , they do not have anything that could be considered an archipelago. The North East passage (North of Russia and Europe) is basically an ocean ocean passage in international waters that follows along the Russian mainland and, from time to time comes in between Russia's mainland and some of its Islands -
but those Islands are more than 24 NM distant from Russia's mainland and thus, you can sail by remaining in international waters.
The CAA is different, both by its scope and by its make up, whereby there are no points whatsoever where you can go through without having to come within 12 NM of the Canadian coast of any of the archipelago's islands. In other words, you must enter at the very least Canadian territorial waters to transit the North West passage.
So what are the competing claims?
Canada: The CAA is a special case because (1) there is nothing like it anywhere in the world; (2) it is covered in impassable ice most of the year, and as result has never been used as an international shipping route to date; and (3) when iced over, it has been used
as if land by the Inuit from times immemorial and it must be preserved as such for them. Therefore, we are justified in considering the archipelago as internal waters of Canada and enclosing then by straight baselines at the edges and "calculate our territorial waters and EEZ from there.
The US: While we recognize Canada's right to internal waters and territorial waters around each of the CAA's islands (which, BTW means they recognize that a great deal of these waters will be Canadian territorial waters no matter what), we do not recognize a right to create baselines at the edges. Moreover, since (1) navigators the world over have been looking for passage through the archipelago (the famed NW passage) as a way to China (that was not under Dutch control); (2) such passage exists and goes through the CAA; (3) this passage is fast becoming available for navigation for a reasonable and foreseeable amount of time every year; and, (4) clearly it connects two parts of international waters, then the US considers the NW passage to be an International Strait.
These differing positions matter because:
Internal waters are waters where the authority of Canada is absolute and unrestricted by anything in the Law of the Sea (LoS), thus we can keep anybody out any time we want, for no reason, at our whim.
Territorial waters are subject to the right of innocent passage of commercial shipping, but we can keep warships and other government vessels from entering at our discretion.
International straits, while traversing territorial waters, are subject to the right of innocent passage by commercial shipping AND warships and other government vessels under strict transit obligations (weapons in stored position, combat systems off, no hydrographic work or any scientific research/experiment to be carried out - self defence only for warships. The country whose territorial waters are so transited do retain, however, all the authority to regulate transit for safety and traffic control and pollution control reasons, amongst others. Whilst it is not in the LoS, I would suspect that, since the LoS and various organizations related to its development and application are now within the aegis of the UN, a country (such as Canada) would likely be able to also regulate on the basis of its obligations (either in international or recognized internal law or in treaty rights) towards aboriginal people.
As of now, Canada and the US have agreed to disagree and have agreed that to transit the NW passage, the US government will ask permission and that Canada will grant permission, the whole without prejudice to either nation's claim.
The final aspect of Arctic sovereignty is the continental shelf. Countries that border on the ocean have some extra rights as regards exploitation of resources within their continental shelf, even if this shelf exceeds the limits of their EEZ. That is why, for instance, Canada has rights to exploit the riches of the nose of the Grand Bank of Newfoundland that sticks outside of our EEZ. As we have seen earlier, the AO is shallow: basically it is almost all continental shelf of the bordering countries. That is why the Arctic nations have agreed to a process to determine who can claim what as their continental shelf in the Arctic: every one has until l "x" date (I can't remember it) to develop legitimate scientific evidence (subject to each other's review) of what it considers it's continental shelf and to present it to an international arbitration panel, leading to an ultimate decision on where each country's shelf ends.
I hope I was clear (if not succinct
