Governments and businesses have long dreamed of an "Arctic Passage" that would allow ships to traverse the northernmost reaches of the globe and thus drastically reduce travel times between the Atlantic and Pacific oceans. That dream moves closer to reality this month as a Danish cargo ship sets out to traverse alone the Northern Sea Route, traveling from Russia's east coast to St. Petersburg. The transit, if successful, will be a milestone — in good ways and bad — but it will still be more a symbol than a genuine transformation of commercial and geopolitical prospects.

The Venta Maersk has left Vladivostok in Russia's Far East, commencing a voyage that will take it through the Bering Strait and across the Arctic to arrive in St. Petersburg by the end of September. The 42,000-ton vessel, which is carrying 3,600 containers of frozen fish, is specially built for the challenging Arctic environment: It has a stronger hull and protected rudders that will allow it to pass through ice floes up to 1 meter thick.

Maersk, the Danish shipping giant that built and owns the Venta Maersk, has no plans to regularly ply the Northern Sea Route. This is a one-off trial to "explore the operational feasibility of container shipping through the Northern Sea Route and to collect data." The company acknowledges that it does not currently see the Northern Sea Route "as a commercial alternative to our existing network" and does not know when it might become one.