Is it that the ice is melting, or the fact that Russia has bigger ice breakers now that are keeping their shipping lanes open?
Russia has bigger ice breakers now
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The US has only one heavy ice breaker and it is based out of Seattle. But it is held together with spit, balling ire and duct tape.
The 3 newest cutters will not be launched until 2027-2028 at the earliest. Like all US cutters, it will be conventionally powered, with a hull designed to travel on the open ocean to Antarctica - it may or may not have offensive weapons on board.
Meanwhile, Russia is churning out nuclear powered heavy breakers like hot cakes.
Any ice breaking will have to be by Canadian or Danish breakers as the US will not have any; none or those will be competitive with the Russians on any level.