The Crystal Serenity, the luxury cruise ship that took passengers up into the Arctic for $22,000 at the low end, has successfully transited the fabled Northwest Passage.

To commemorate the moment, Crystal Cruises posted a photo Sept. 5 with this message on Instagram: “Crystal Serenity has successfully sailed the fabled Northwest Passage, becoming the first large luxury cruise ship to complete transit of the Arctic region. To commemorate this historic moment, guests on board donned their special Northwest Passage red parka jackets for a photo … Learn more about our 2017 voyage by calling a travel professional or visiting crystalcruises.com.”

The Crystal Serenity began its voyage in Seward, Alaska, on Aug. 15, and reached Ilulissat, Greenland, on Sept. 6. It will make a port of call in Bar Harbor on Sept. 12 en route to its final destination of New York City on Sept. 16. Associated Press map with information from Crystal Cruises

The National Snow and Ice Data Center, which tracks sea ice daily, had this to say about the accomplishment: “This is the largest ship thus far to navigate the Northwest Passage and is accompanied by an icebreaker ship and two helicopters. The ship sailed through the Northwest Passage in less than three weeks – 52 times faster than Amundsen’s nearly three-year voyage.”

The meaning of this – at once crass and profound – is that formerly remote Arctic is now open to high-end summer cruise ships, if you’re willing to pay. And to hear scientists tell it, this is only the beginning.

Cruises are one thing – but as Arctic sea ice melts and covers less of the ocean for less of the year, we should see all kinds of maritime incursions. Most significant, perhaps, is shipping – being able to use the Arctic could save a great deal of time and money for companies currently using the Panama and Suez Canals for transits between Asia and the U.S., or Asia and Europe.

In a new study in Geophysical Research Letters, a team of researchers from the University of Reading in the United Kingdom use a series of climate models to present a highly detailed analysis of how open the Arctic will become to shipping routes circa 2050 and 2100. And the answer is quite open indeed, depending of course on precisely how many greenhouse gases we actually emit in this century.

For the moment, Arctic shipping is growing but remains a bit of a niche activity, explained Nathanael Melia, the study’s lead author. “What we’ve seen over the last 10 years is that shipping companies have been doing some test voyages,” Melia said. (The work was co-authored with two other colleagues, Ed Hawkins and Keith Haines of the University of Reading.)

The new study finds that for different greenhouse gas emissions scenarios, and for different types of ships – some standard open water vessels, some ice-strengthened vessels – the opportunity for using swifter Arctic routes could greatly increase.

The study in particular considered shipping to Yokohama, Japan, from either Rotterdam – a key European port – or New York, a key American one. At present, the route from Europe would tend to use the Suez Canal and take about 30 days, and the route from New York would use the Panama Canal and take about 25.

But if the European-Asian trip instead used the Northern Sea Route, along the north coast of Russia, the trip could be cut to 18 days, and the distance would shrink from 11,580 nautical miles to 6,930 nautical miles. For the American-Asian trip, meanwhile, using the Northwest Passage, through the Canadian archipelago, could take 21 days, rather than 25.

Clearly, then, there are savings to be gained here, if the ice permits it.

And there’s little doubt that in the future, the Arctic will have even less sea ice than it does now, especially in the low ice month of September (current Arctic sea ice extent is on pace for the second minimum extent on record).

But precisely how little ice will still depend on how much we heat the planet – whether we achieve something like a (very difficult) Paris policy of limiting warming to below 2 degrees Celsius above preindustrial levels, or whether we let it rip and continue high levels of emissions throughout the century.

The changes will come gradually at first, Melia said.

“Initially, the Northwest Passage, say for the next 15 or so years, can be navigated every now and again, but it’s pretty unreliable, and it can end up taking longer,” he said, referring to September trips for open water vessels, rather than ice specialized-ships. “So that route, at the moment, is a real specialist route.”

“But around midcentury, that route becomes more reliable,” he continues.

Even in a low emissions scenario, Melia said his study forecasts a “twofold increase in the prospect of these routes becoming open” by the middle of the century (again, in September and for standard open water ships). But if we’re really going for broke with emissions, the expansion is even more dramatic, and by the middle of the century we could even see non-ice strengthened ships going straight over the pole.

Indeed, one of the most striking developments is that for ice-strengthened vessels in the Paris scenario, and for both open water and ice-strengthened vessels in the high emissions scenario, it could become possible to take this Earth-capping route that nobody is even attempting now. Dubbed the Trans-Polar Sea Route, it saves even more time on the trip between Europe and Asia.

“By midcentury in a high emissions world, it’s common,” said Melia of September transits of the Trans-Polar Sea Route.

Granted, we won’t move into this world immediately, nor will it be the case that shipping through the Arctic will be available year round – it will still have seasonal constraints. The dark polar night during winter will still be very cold, and the seas in winter will still be full of ice. So business models may have to adjust to shipping sometimes through the Arctic and sometimes through the established canals.

But that doesn’t change the punch line – more navigation will be coming, simply because it can. “There’s going to be a lot more potential for ships up there,” said Melia.