A Danish cargo container vessel is about to set out on a voyage that will be a milestone in the opening of Arctic waters to marine shipping — and it's a direct result of climate change.

Why it matters: The Arctic has been warming at least twice as fast as the rest of the globe, and sea ice has declined sharply since 1979. As the ice melts, Arctic shipping routes are becoming more attractive as an alternative to sailing through the Suez Canal.

The details: Danish shipping giant Maersk will send the first cargo container vessel unaided through the Arctic's Northern Sea Route, departing from Vladivostok this week and passing the Bering Strait on Sept. 1.

The ship, known as the Venta Maersk, will move across the top of Russia from east to west and should arrive in St. Petersburg by the end of September.

This route used to require the help of nuclear-powered icebreakers, and was not economically attractive for cargo shipping companies.

Maersk is sending the Venta at a time when Arctic sea ice is nearing its seasonal minimum, and is more fractured than it is during the winter.

During the period from 1979 to 2017, sea ice has declined by about 33,200 square miles per year, or 13.2% per decade compared to the 1981-2010 average, according to the National Snow and Ice Data Center.

According to Maersk, the new Venta Maersk ship will make this voyage as a "trial passage." The Venta Maersk is a new, ice-hardened vessel that can sail through sea ice floes that are up to about 1 meter thick. The approximately 3,600 containers on this specific run will contain frozen fish.

"The trial passage will enable us to explore the operational feasibility of container shipping through the Northern Sea Route and to collect data," Maersk said in a statement. "Currently, we do not see the Northern Sea Route as a commercial alternative to our existing network which is defined by our customers’ demand, trading patterns and population centres."

What we're watching: According to Maersk, the company doesn't have a timetable for when routine Arctic shipping runs will be feasible, and experts told Axios that the idea that such routes will be heavily traveled in a decade or two are flawed.

Even with thinner, sparser sea ice, shifts in Arctic winds can quickly transport ice into shipping lanes, causing delays.

The era of just-in-time shipping makes that problematic, said Malte Humpert, the founder and senior scholar at The Arctic Institute.

"Today, the passage is only feasible for around three month a year. Furthermore, we also must consider that ice-classed vessels are required to make the passage, which means an additional investment," Maersk spokesperson Janina von Spalding told Axios via email.

What they're saying: Arctic scholars see the voyage as symbolic, but not an indication that an Arctic shipping boom is upon us yet.

“This is a climate change story," said Michael Byers, a professor at the University of British Columbia. He cited the decline of sea ice as the major factor that allows the route to be used.

“I think it’s a small step towards a future where we’ll see much larger container ships using the Northern Sea Route, but I wouldn’t want to exaggerate the relatively small step,” Byers said.

“The fact that you can now ship with a container ship through the Arctic along the Northern Sea Route, when even just 10 years ago that was not even remotely possible, shows shows how quickly and how dramatically climate change is affecting the region."

— Malte Humpert, Arctic Institute

There are environmental concerns that go along with any increase in Arctic shipping. The International Maritime Organization is moving toward a ban on Arctic ships' use of heavy fuel oil, which emits soot and other pollution that darkens sea ice, thereby accelerating sea ice melt.

Maersk said its new vessel won't use such fuel, although such a ban is not yet in effect.

Go deeper: