Jill Christie, the Canadian naturalist who was driving our Zodiac inflatable, cut the outboard, leaving us drifting silently. Around us towered gigantic ramparts of ice, up to 100 metres high. An occasional bang, like a gunshot, echoed off the opalescent floating mountains as a crack developed somewhere within a berg. We were careful not to get too close, in case one of the monsters suddenly split or flipped over. This was the Ilulissat ice fiord, which cuts deep into Greenland's southwest coast. It is perpetually choked with bergs that become grounded at its shallow entrance, until they melt enough to drift out into Baffin Bay.

After an hour in the chilly air among the icebergs, we motored out into the open sea and returned to our ship. Soon we were enjoying a dinner barbecue, with wine, music, and dancing on deck in the warm, late-lingering sun of August as we cruised past the outermost bergs. It was a magical evening, but there was an irony that I could not ignore. For the very warmth that made these pleasures possible threatens the world of the Far North that we were experiencing.

“We are witnesses to one of the most striking examples of climate change in the Arctic,” U.S. meteorologist Robert Corell told a reporter for Agence France-Presse a week after my trip, during a flight over the Ilulissat glacier. Descending from Greenland's two-kilometre-thick central ice cap and feeding into the head of the ice fiord, it is the fastest-flowing glacier in the world, a conveyor belt that moves at up to 30 metres a day. So many bergs calve off it that they represent about 90 percent of all the icebergs reaching the North Atlantic. It was possibly a berg from Ilulissat that sank the Titanic. But now the glacier is also melting far back from the coast, and fast.

Its lower edge “has receded by more than 10 kilometres in two or three years after having been relatively stable since the 1960s,” Corell added. The leading author of the 1,400-page Arctic Climate Impact Assessment, he was in Greenland for a conference of environment ministers, scientists, advisers, and activists from 22 countries last August. The Greenpeace ship Arctic Sunrise was in port to provide logistical support and focus world attention on global warming.

As for me, I arrived in Ilulissat on a small, ice-reinforced Russian research vessel, the Akademik Ioffe, which was chartered out to Peregrine Adventures for summer eco-exploration cruises. With 65 fellow passengers, I was there as a guest of the company, mainly to see the Arctic and its ice, while there was still time. In fact, the itinerary of our 11-day trip, which began in Canada's Northwest Passage, was dependent on quirky and ever-shifting ice conditions. And I kept meeting people who told me how seriously climate change was affecting their lives.

Lancaster Sound, the waterway between huge Baffin and Devon islands, used to freeze over nearly every winter. But Capt. Keith Jones, our ice pilot, said it has not frozen for the last three years, a dramatic development. An icebreaker still had to clear the way for our ship to get into the ice-choked harbour at Resolute Bay. And we were the first ship of the year to make it into the anchorage at Pond Inlet, a large Inuit community. (Our arrival was such an event that dozens of children swarmed the beach where we landed and pestered us good-naturedly for hours.) But the overall picture was of a rapidly evolving climate. “We used to be able to cross the sea ice safely all winter,” one Pond Inlet man told me outside his home. “Now we go inland,” pulling the family in a sled towed by a snowmobile, “and fish through the ice on lakes.”

For some, the big melt is a partial blessing. Nikolai, a Greenland fisherman I met at the market in the town of Sisimiut, told me that the harbour there no longer freezes. Until around 10 years ago the ice was usually half a metre thick. Fishermen had to store their boats on land in winter. No longer. They can leave them in the water, which saves trouble, and the fishing season lasts longer.

And yet, the changing ice conditions are inconsistent and can fool even experienced mariners. Judging by satellite imagery, our ice pilot and Russian captain reckoned that the ship could likely push its way through loose pack ice in the middle of Baffin Bay and cross by the shortest route from Canada to Greenland. But we ran into hard pans of multiyear ice and had to turn back. We went north and tried anew. Again, the ice closed around the ship, forcing another retreat and a daylong detour to get around the ice.

A highlight of the trip was the abundance of Arctic flora and fauna. Mosses, dwarf shrubs, and tenacious tundra flowers flourished in the nearly round-the-clock sunshine of the summer months. Bearded and ringed seals poked around in the ice pack. Huge, shaggy musk oxen grazed on the spongy tundra grasses but fled as we approached. Our Zodiacs skirted the base of cliffs where tens of thousands of murres, kittiwakes, and glaucous gulls nested. While hiking, we happened upon the carcass of a beluga whale that apparently had been killed and butchered and then dragged inland and scavenged by a polar bear. One of our guides surmised Inuit hunters had killed the whale; only they live in close enough proximity to the site, he said, and only they have the right to kill the whales. We saw bears shambling along on the ice and swimming near us in the sea.

But the ever-shorter season of solid pack ice threatens the polar bears' ability to hunt seals, their main prey, and put on weight for winter. It also tempts them to encroach on human settlements to find food, which leads to more of them being shot. On land, the permafrost is melting, creating problems for wildlife and people as well.

Our last night we sailed 160 kilometres up the world's longest fiord, a deep marine canyon that twists its way between stunning peaks. At the head of the fiord was the tiny airport from which we would fly back to Canada. Before the flight there was time for an inland bus ride to view the vast Greenland ice cap. It spanned the distant horizon like a low-lying blanket of fog and oozed its way downhill in a few places, where glaciers flowed into valleys.

It was thrilling to see this natural wonder, the largest repository of ice outside Antarctica. But as I flew home, it was sobering to realize that even the seemingly endless and eternal ice cap is now melting. Given the pace of climate change, mine may be the last generation privileged to see the Arctic in anything like its traditional diversity and splendour. -

ACCESS: For more information or to book Peregrine Adventures's Arctic cruises, visit Trek Escapes at www.trekescapes.com/ or phone 1-866-338-8735. Fares start at US$4,745 per person, based on double occupancy, including charter flights out of Ottawa to connect with the ship. There is a doctor onboard, but passengers should be in condition to handle steep gangways to and from the Zodiacs, and to take at least short hikes.