RADML David Gove, Oceanographer/Navigator of the Navy, has published an article in Proceedings, Arctic Melt: Reopening a Naval Frontier, which discusses the strategic impacts of melting ice in the Arctic.
I am a global warming skeptic (that man is responsible), so, I looked for a political angle in the Admiral's writing, and there is none, just some thoughts for us to consider as the Arctic becomes another sea which is navigable year round, and exploitable as well.
It's interesting, apparently this ocean has been navigable before, "Core samples from the Lomonosov Ridge suggest that some 55 million years ago semitropical waters rich in organic matter covered the Arctic basin, perfect conditions for the formation of vast hydrocarbon beds."
Because the US has not ratified the latest Law of the Sea Treaty, we are being shut out of negotiations ongoing that will determine the future of many of those resources, which include 90B bbl of oil, and trillions of cubic feet of natural gas, not to mention vast mineral resources.
So, it's a good read, if you can access the article (I believe it's on the free side of the USNI's web site).