For most of human history, the Arctic Ocean has been an ice-locked frontier. But now, in one of the most concrete signs of the effect of a warming climate on government operations, the Coast Guard is planning its first operating base there as a way of dealing with the cruise ships and the tankers that are already beginning to ply Arctic waters.
The New York Times has been especially good about keeping up on arctic/subarctic news as it relates to warming. In fact, my thesis was in part inspired by the multipart series they put out on the subject - with some of the geopolitical consequences this blog attempts to address - a year or two back.
One key concern for the United States in regards to sealanes in the Arctic is the shared border with the Russian Federation. Russia has been particularily bold in its claims on the Arctic; often invoking Stalin's immense claims to the area (almost a half of the sea) from his commissioned expedition in 1937.
Still, the only major Arctic claimant that hasn't signed the UN Law of the Sea is the United States. Simplified, this treaty stipulates the continental shelf as the seaward border of the territorial claims that could be made. The result has been a scramble to chart the Arctic Ocean's bathymetry using deep sea sonar.
Regardless of the method of delinating the borders, it is only a matter time before conflict arises over the distribution of artic resources. With the big prize being undersea oil and natural gas, it would not at all be a stretch to suggest slant-drilling (if not feasible now for undersea oil exploration, it will likely be by the time large scale exploration ramps up) may be the cause of such a conflict. It undoubtably has been the given reason for a number of armed conflicts, the most immediate example being Saddam Hussien's justification for the invasion of Kuwait.