This expedition cruise in the wild Arctic is full of nail-biting moments

The ice is talking and there is treachery in its voice. We hear it coming for us in the gloom. A thick fog has swallowed the rusted basalt cliffs behind us and darkened the surrounding deep water. We shift nervously in our small boat, the ominous sound of grinding teeth growing louder.

We are on the east coast of Greenland deep in Scoresby Sound, the world's longest fjord system. An hour earlier it had resembled a perfect postcard destination. Jagged icebergs floated past, blue and white cathedrals sweating profusely beneath a bright morning sun. Gulls circled noiselessly overhead. A distant glacier glistened, its crevassed surface a cracked mirror reflecting an azure sky.

In the pure Arctic air the world appeared in high definition, its volume muted.

We had been impatient to explore after two days sailing from Iceland on the icebreaking expedition cruise ship Greg Mortimer, named after the first Australian to summit Mount Everest. Rugged in thermal clothing and wrapped in waterproof jackets, we'd crowded into Zodiacs - military-grade inflatable craft - and motored into the vastness of Romer Fjord.

But now, just 15 minutes later, a thick mist has descended like a stage curtain falling prematurely on an absorbing play. An unexpected ice floe has also engulfed us, transforming the surface of the fjord into a fractured white quilt. The ice crackles, pops, moans. Adolescent icebergs the size of trucks bump and grind against our craft. A nearby Zodiac, its propeller wedged in ice, is nudged and then lifted into the air by a chunk of ice before being pushed on to another piece.

The floe moves with menace, muttering to itself. Behind your back this landscape shifts constantly. The adrenaline jumpstarts your imagination. It's as if the ice is stalking us, reviving a dim memory of a horror movie scene that has haunted you since childhood - a man trapped in a darkened warehouse surrounded by storefront mannequins slowly coming to life.

Within moments the floe separates and then surrounds our boats. Our guides - many of them Arctic veterans trying to disguise their growing concern - have never seen it behave like this. It defies logic - and the current. Its sheer power makes you swallow hard. We're vulnerable here. Trapped between two large moving pieces, most of their mass hanging pregnantly below the surface, and our inflatable rubber craft could easily be crushed.

This wasn't in the brochure. We came to the Arctic to admire polar bears from afar and gaze at primeval landscapes doomed by climate change to vanish in the next few generations. Here, on our first day off the ship, is a blunt reminder that our planet's last truly wild places remain defiant, unpredictable and even, like today, malevolent.

Every time an opening appears offering clear water and a chance to return to the ship, it closes. Your imagination veers to worst-case scenarios. The seabed off Greenland's coast is littered with the bones of hundreds of sailors, victims of the Arctic's wrath. Are we to join them? You yearn for the comfort and warmth of your luxury cabin. You are wearing two pairs of gloves but your fingers are as cold as the air.

At that moment help arrives. The skipper of the Greg Mortimer starts the engines and manoeuvres through the ice, expertly turning and weaving the ship to create eddies and currents. The movement disrupts the ice's advance and begins breaking it apart. That noise of gnashing teeth, of ice chunks scraping and creaking against one another, now sounds like frustration.

Our foe in retreat, we make it comfortably back to the ship in time for a first class, all-you-can-eat buffet lunch. A short nap afterwards, too. We've just witnessed the true nature of the Arctic. Our nerves deserve a rest because there is more to come.

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A hint of the exotic, a dose of danger and a decent dollop of luxury. High-end adventure tourism in some of the world's most inhospitable regions, from the North Pole to the Himalayas and the Antarctic, is growing in popularity. But these are not vacations for those who fantasise about lazing on sun lounges sipping cocktails, although the Greg Mortimer, operated by Aurora Expeditions, boasts two spa baths on its top deck, a sauna, a massage service, several bars and endless views from the top of the world.

Instead, these voyages to far-flung locations offer an opportunity to leave the sanitised world behind, to encounter the unexpected without sacrificing all the creature comforts of modern life. Our three-week expedition into the Arctic offered a taste of everything.

After our encounter with the ice we moved further into Scoresby Sound, which stretches more than 350 kilometres inland from its mouth in the Greenland Sea. Depths here can descend more than two kilometres. But it's what you see above the water line - the towering cliff faces and rock-strewn beaches and massive glaciers carving their way slowly through the mountainous terrain - that ignites the imagination. One evening we hiked across a twisted rock formation more than a billion years old before reaching a peak overlooking an enormous blue bay. It was 9pm. The northern sun, which hadn't set for months and would not even graze the horizon for another few weeks, was at our backs. Its glow amplified the colour of everything. Estimating distances was futile - the deceptive Arctic light made mountain ranges swallowing the horizon appear so close you could touch them. Our group rested on boulders and stared in awed silence, like pilgrims on a first visit to a holy site. No-one spoke. No words were adequate.

But in the following days we noticed something missing from the oil painting landscapes that greeted us each morning as we parted our cabin's blackout curtains and stepped outside to embrace the cold air. Where were the animals? Greenland, the largest island in the world, is vast. But life is sparse. Its ice sheet covers almost 90 per cent of its two million square kilometres and in some places lies three kilometres deep. Our treks inland across soft tundra studded with yellow and purple wildflowers were interrupted by flocks of honking geese and quarrelling Arctic terns. We'd stumble across the scat and footprints of foxes and Muskox. But the beasts themselves - particularly that apex Arctic predator, the polar bear - remained elusive.

Patience, urged Greg Mortimer - the man, not the ship. At 71, Mortimer had joined the vessel named after him as our expedition leader. The founder of Aurora Expeditions, he knew this land and its deceptive qualities well. It was in Scoresby Sound that the inveterate climber had undertaken a climbing trek with his son a decade earlier. Scaling an escarpment, Mortimer fell and broke his back. The man who had summited Everest in 1984 without oxygen was in luck. A scientific party nearby answered their distress calls. A helicopter was called. Mortimer was rushed to Iceland where doctors inserted steel rods to help knit his shattered bones.

Mortimer's raw enthusiasm for wild and near-unreachable places set the rhythm of daily ship life. Each morning his voice would crackle enthusiastically through our cabin speakers. "Good morning, good people," he'd announce. "Look outside your window - the view is amazing. Breakfast will be served in 15 minutes and we aim to have you off the ship soon after."

Perhaps it was the cold air, the frequent hiking across tundra and up steep hills, or just the prospect of confronting something entirely alien each day. But our appetites were enormous throughout the expedition and breakfast set the tone. There were cereals, fruit and various yoghurts. Lashings of crispy bacon. Vats of hot beans and scrambled eggs. Omelettes made to order. Hot coffee and iced juices.

By lunchtime stomachs would be growling again, to be quickly sated by a buffet with dozens of options ranging from lentil soups and salad to cold cuts, roasted meats, burgers and perfectly seasoned vegetables. Dinner was an a la carte menu with brilliant waiter service. Here was yet another Arctic mystery. How did the kitchen pull off the daily miracle of serving superb fresh food after weeks at sea?

Our finest culinary moment, however, came a couple of days later after our eerie encounter with the ice. We'd arrived on Bear Island on a morning when the skies were clear and the mosquitos thick. As we trekked across a rocky outcrop hoping to spot Muskox a loud crack shattered the serenity. We turned in time to see an iceberg sever itself in two, a process called calving. Hundreds of tonnes of shattered ice exploded into the shallows of the bay. Soon after reboarding our Zodiac our guide grabbed a chunk of ice floating by in the sheer blue water. It resembled glass. The absence of air bubbles, he explained, indicated it was at least several thousand years old, a frozen relic from the base of a glacier where the enormous pressures had eliminated every trace of air. He stabbed it with a pocket knife and we sucked on the shards. Nothing ever tasted so clean and pure.

We'd planned to visit the Inuit village of Ittoqqortoormiit as we left Scoresby Sound. In recent years Greenland's melting ice sheet - Arctic temperatures are rising six times faster than elsewhere in the world - has caused the town's locals to tread warily. Polar bears, struggling to catch seals and other traditional prey, haunt its outskirts searching for food. But another unexpected ice floe appeared, cutting off the town and making landfall impossible. So we sailed north, passing vast suburbs of icebergs, and into another fjord system to follow snorting herds of walrus and gaze at the endless white cliffs of the Waltershausen Glacier. Reindeer, the biggest burdened by felt-covered antlers the size of small, leafless trees, grazed on nearby hills as gulls circled and cackled above.

But it was polar bears everyone wanted to see. And they were waiting for us, just as Greg Mortimer had promised, across an open sea on a remote archipelago that time had all but forgotten.

Svalbard, a series of islands riven by glaciers, ice sheets and saw-toothed mountains, lies roughly halfway between Norway's north coast and the North Pole. It has barely changed in the four centuries since its discovery by the Dutch explorer Willem Barentsz, whose reports of enormous schools of bowhead whales - highly regarded for their exceptional reserves of oil and blubber - triggered centuries of frenzied hunting that almost wiped out the species.

One afternoon we climbed the island summit of Ytre Norskoya to survey its sheltered bay where, in the early 1600s, so many whales were slaughtered it was said a man could walk across the water without getting his feet wet by using their bloated carcasses as stepping stones. A large, rusted iron cross stood defiantly at the peak, commemorating the lives of 160 Dutch whalers who had lost their lives pursuing the beasts and been hastily buried in shallow graves barely a metre deep. A thick layer of impenetrable permafrost lies beneath the Arctic soil. It is why the dead are no longer welcome these days in Svalbard's earth. The permafrost is thawing because of global warming, increasing the threat of dormant pathogens and contagious viruses being unleashed. In Svalbard's capital Longyearbyen, home to the almost 3000 people who live in the archipelago, the dying are now taken to the Norwegian mainland for burial.

But it was on Kvitoya, the most remote of Svalbard's eastern islands, that we found what we had been waiting for. As we bobbed several hundred metres offshore on a frigid morning, the Arctic fog - that infernal stage curtain that several times had obscured our views - fittingly lifted to reveal the biggest stars of the northern world.

Several polar bears lounged near the beach, their sluggishness explained by an unidentifiable carcass lying in the shallows they had been feasting upon. Even from a distance their size and power - their paws are as big as dinner plates - was impressive. Every few moments one would lift its head as our scent caught its attention, its nose hundreds of times more powerful than that of a bloodhound.

The polar bear - a close relative of other northern hemisphere bears - is the poster child of global warming, its hunting territory shrinking as its icy habitat disappears. But despite their hold on the public imagination, we still know so little about them. Bears travel vast distances in search of food. Much of it is done alone, across deep water and through shifting ice - a landscape that changes dramatically by the hour and offers no guiding landmarks. We don't know how they find their way, even though they manage each year to return to the same dens and breeding grounds.

The following day we came across another eight on the beach of a headland at Kapp Lee, a gathering our guides said was almost unprecedented. We tried to fathom the complex relationships between them. There were mothers with cubs while solitary males stalked the beach, squabbling over the remains of an animal lying close to shore. Even the experts were confused by some of the intimate alliances playing out. As always, the enigmatic bears kept their secrets to themselves.

Three weeks of an intense expedition - most days involved leaving the ship twice and either hiking on land or sightseeing on Zodiacs - required plenty of mental processing. Some evenings your mind was numb, overstimulated by the sheer size and ruggedness of the surroundings. One afternoon we travelled by Zodiac beneath black mountains stained white by the guano of millions of nesting birds. The sound was cacophonous, the height of the cliffs so gothic and intimidating it could have been a scene from Games of Thrones.

"It'll take you months to truly appreciate what you've seen," Greg Mortimer told me. He was right. A great way to do this was to attend the evening debriefing in the ship's modern lecture theatre just before dinner. There, over a cocktail and a snack, the crew of trained biologists, geologists and naturalists took passengers through highly detailed visual presentations summarising the day and explaining the intricacies of what we had seen.

"Feels like I'm back at school," someone joked one night. But classrooms were never as fascinating and the overwhelming lesson from our journey will never be forgotten.

The northern ice cap is shrinking by 13 per cent every decade. Greenland's ice sheet is shedding 270 billion tonnes a year. If that process continues, raising sea levels globally by more than seven metres, the entire region will be unrecognisable within decades.

The Arctic, one of the last truly primitive and raw places left on earth, might be vanishing. But it's not disappearing without a fight.

The ship: Greg Mortimer, Polar Class 6 icebreaker with a state-of-the-art x-bow design allowing for smoother sailing. It has a 180-degree observation deck, hydraulic viewing platforms, modern lecture lounge, library, two restaurants, gymnasium, sauna and wellness centre. Launched in 2019, it's named after the first Australian to climb Mount Everest. (Mortimer founded Aurora Expeditions, the ship's operator, in 1991).

The size: 104 metres long, eight decks, 79 staterooms, 130 passengers

Get on board: Prices for Arctic expeditions start from $15,900 and cruises can range from eight to 30 days. The Greg Mortimer also offers expeditions to the Antarctic Peninsula.

Good to know: Significant discounts of 20 per cent or more usually apply to early bookings, while some expeditions also offer air credits of $US2000 ($2960) per person.

Explore more: auroraexpeditions.com.au

The writer was a guest of Aurora Expeditions.