Take the Northwest Passage, which the MS Bremen also sails. Polar Class cruisers now weave past dozens of islands described as the Canadian Arctic Archipelago, passing along the northern Canadian and US Alaskan coasts.

But it’s a route that was once completely impassible. While the cruise companies promise a voyage on “one of the world’s greatest sea routes, sailing in the wake of legendary explorers like Captain James Cooks and Roald Amundsen”, the experience is a world away from what Cook and Amundsen experienced, stranded as they were on small wooden vessels with frozen gruel, frozen canvas hammocks, frozen decks and frost-bitten digits.

While there is a vital navigation and climate history to the Northwest Passage, invoking legendary navigators like Cook and Amundsen to sell cruises mistreats the truth. Sailing through the Northwest Passage is a 21st century story. And if cruise operators were being super honest with the facts, advertisements promoting these adventures would ring alarm bells for prospective travellers.

The major reason why it’s now possible to sail through the Northwest Passage is not Cook and Amundsen’s legacy, but rapidly melting ice sheets, rising sea levels, and ice-breaking cruisers.

From the 15th century onwards, brave seamen headed into frozen seas to locate the legendary yet elusive Northwest Passage. Navigators like Cook, and those before and after him, understood the risks of being trapped in the icefields, starving slowly and freezing to death.

Cook first set out to find a sea track offering a shorter route between the Far East, China and Alaska, leading into the Atlantic, in 1776. He commanded the HMS Resolution, a 462-tonne wooden-hulled vessel, with instructions to discover a navigable sea passage from the northern Pacific above Latitude 65 degrees North.

His mission failed in August 1778. His journal reveals that progress was halted by “ice which was as compact as a wall and seemed to be 10 or 12 feet high at least”. Unable to proceed, he sailed back to Hawaii to make urgent repairs, intending to return the next summer. He never did.

Almost 130 years later, Amundsen, a Norwegian explorer scientist, succeeded where Cook had failed. On the Gjoa, a small fishing boat, Amundsen managed to weave a way through the ice above the Canadian and Alaskan northlands. In August 1905, he reached Victoria Strait, the last “unsailed link in the Northwest Passage". Amundsen reached Nome in Alaska in 1906. It took him more than three years to traverse the passage from the Atlantic and he spent two winters trapped in the ice.

Commercial small cruise tourism commenced sporadically in 1984 but until 2009 Arctic pack ice still prevented regular commercial marine shipping through most of the year. NASA now predicts that the Arctic’s summer ice cover could be lost by 2100 – that’s 82 years away - or one healthy person’s average lifespan. Existing data confirms the polar icefields are diminishing as land ice sheets melt and rising sea water temperatures reduces the formation of ocean ice.

The cruise ships sailing the now open waters in Amundsen’s wake are a far cry from his small fishing boat. Today, luxury vessels with "ice-class" double hulls transport a thousand or more leisured passengers in sleek comfort through the Northwest Passage. The last ice barriers are broken.

Under construction is one luxury liner with super reinforcement making it an "ice-breaking cruise ship capable of sailing though ice some 2.5 metres thick". The maiden voyage, planned for 2019, is promoted as a "voyage of initiation", with naturalists and speciality lecturers on board.

So yes, the Arctic, Pacific, and Atlantic oceans are now connected for business. But what will be the hidden and future environmental costs, beyond the deaths of polar bears that come too close? Cruise ships will be gas and electrically-powered, but if commercial ships set up a steady fleet in their wake, consider the negative outcomes: accidental fuel discharges, human waste, lost containers, shoreline erosion and potential collisions.

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Who will take responsibility for clean-ups or sea rescues if needed? The Canadians, the Americans, or the Russians? These icy waters remain contested territory. How will international law of the sea be interpreted as the ice melts away? Whose claims will prevail?

Increased human habitation will encroach on the last pristine areas of these icy northern seaways - damaging not only the habitat, but putting vulnerable species, like the polar bear, at greater risk as they encounter mankind.

Instead of dreaming of "sailing in the wake" of Cook, Amundsen and other navigators, this nightmare prospect for the Northwest Passage should sound an alarming wake-up call to everyone, including passengers on leisure cruisers.

Dr Suzanne Rickard is the author of Sailing with Cook: Inside The Private Journal of James Burney RN.