
The Telegraph has an opinion piece by retired Royal Navy Commander and former CO of the Ice Patrol Vessel HMS Endurance, Tom Sharpe OBE.
He feels, as I do, that we are headed for conflict over claims to Antarctica. It is after all, the last land area on earth where no nation exercises sovereignty.
China’s presence in the Antarctic is growing rapidly and, as they have shown in the South China Sea, they may choose not to accept the decisions of international courts.

Adapted from a 2021 Chinese environmental evaluation report submitted to the Secretariat of the Antarctic Treaty. Source CSIS
What this boils down to is that, after courts make their decisions, we may have to fight in Antarctic to make those decisions stick.
We don’t seem to have given much thought to the possibility of combat in and around Antarctica, but I believe it is a real possibility, perhaps not soon, but beginning in 2048 when the Antarctic Treaty comes up for renegotiation. 24 years may seem to be a long way off, but we are building now the assets that will be available in 2048.
By then the rapidly growing Chinese presence in Antarctic, as well as their Navy are likely to be in a very strong position. We are already seeing the Chinese apparently establishing dual use (civilian and military) facilities in Antarctica.
In the interim, we can expect China and perhaps others to try to skirt the rules to strengthen their presence. We need to monitor and challenge any gray zone operations.
Command Structure:

These are the Unified Combatant Commander’s Areas of Responsibility.
There is an obvious reason that Antarctica does not seem to be on anyone’s radar. Looking at who is potentially responsible for operations in the Antarctic, it is a hodgepodge. Various parts of the Continent might fall under SOUTHCOM, AFRICOM, and INDO-PACOM.

US Navy Fleet Organization
3rd Fleet, 4th Fleet, 6th Fleet, and 7th Fleet all have a nominal slice, but none of these commands consider the area their primary concern.

World map of oceans : English version. By Pinpin via Wikipedia.
There is no single national command authority that covers all of Antartica or the Southern Ocean. Really no one is in responsible for the area below 60 degrees South.
It seems likely that in the near term, Southern Ocean fisheries will require some protection. The only nation I have heard of doing fisheries protection in the Southern Ocean outside their own EEZ is New Zealand.
The Coast Guard currently operates the only US polar icebreakers. At some point the Coast Guard may become involved in fisheries protection in the Southern Ocean. If there is conflict in Antarctica, Coast Guard assets will likely be needed to gain access.
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