On thinning ice: This summer I got up close and personal with glaciers

This summer I ventured into the land of ice at the top of the world. I wandered among towering icebergs, and came face to face with calving glaciers.

Canada has an enormous amount of glacial ice — the third most in the world after Greenland and Antarctica. A portion of this is in the mountains of the west, but most is in the high Arctic. Over the years I've had the privilege of visiting these frozen features and witnessing first-hand the changes that have taken place as many start to vanish before our eyes.

My first visit to a glacier was in 1973 at the Columbia Icefield between Banff and Jasper in Alberta. The icefield feeds six glaciers, including the famous Athabasca Glacier. It is the only glacier in Canada that you can drive up to and walk on. 

But each time I have returned over the last half century, I've been astounded at how much the glacier has changed, not only by how much it's retreated — more than a kilometre back — but also how it has thinned, now sitting lower in the valley. 

This past summer I had the opportunity to repeat a different trip to see northern glaciers. It was back in 2008 that I'd first sailed to Greenland and the Canadian Arctic aboard a cruise ship.  

This time, we started in Kangerlussuaq on the south western coast of Greenland. Our route carried us up the rugged coast, then over to Baffin Island and Devon Island in Canada. The ship was equipped with 12-person zodiacs that ferried us to shore to visit communities located at the mouths of rugged fjords. There are no trees that far north. The land is covered in tundra, which is quite colourful, but the vegetation doesn't grow more than ankle high. 

From a few kilometres offshore, looking along the Greenland coast, you can see several glaciers at once, dripping like candle wax between the coastal mountain peaks. I could see a difference in the landscape since my first visit in 2008. Many tongues of ice are farther up the valleys with large areas of exposed rock at the bottom that used to be covered in ice. 

Some glaciers still do reach all the way down to the sea, especially at Ilulissat, a World Heritage Site, where a fast moving glacier calves icebergs the size of ten-storey buildings that drift off into the North Atlantic.  

Approaching one of these gleaming mountains of ice in a small boat is a nerve-wracking experience, especially when you consider that most of it is below the surface of the water. The zodiac drivers are instructed to remain three times the height of the iceberg away because these monsters are constantly changing and can roll over or break into large pieces without warning.

Scattered across the surface of the water are smaller chunks of ice known as growlers and bergy bits depending on their size. I managed to reach over and scoop up a small piece that I broke apart and handed around to fellow passengers to taste. Popping a piece in my mouth, it crackled and popped as air bubbles that had been trapped in the ice when it froze were released. I realized that those bubbles were likely tens of thousands of years old, so I was breathing air that could have passed through a wooly mammoth. It is those same bubbles that scientists measure to trace the history of the Earth's climate.

Farther north, in Croker Bay on Canada's Devon Island, we motored along the face of a two-kilometre-wide glacier that runs right down to the sea. The jumbled wall of ice towered above our tiny boats. Suddenly, a loud cracking sound followed by a thunderous rumble rolled across the surface of the water. We turned to see a large chunk of ice tumble off the ice wall, sink down, then emerge like a white whale, slowly settling. A new iceberg was born.

In the future, as glaciers retreat inland, this may be a much rarer experience.

On the return trip across the vast expanse of Baffin Bay, about 100 kilometres from shore, we encountered a large swath of floating sea ice. This was not glacial ice, but small floes of the sea ice that forms on Arctic waters in winter.  

Wandering among the ice floes in the zodiacs, we saw standing on one of them the iconic symbol of the north, a polar bear, hunting for seals. That ice is their hunting ground, but there's less of it than there used to be. The Arctic's permanent sea ice is shrinking. It's thinner than in the past, and its minimum extent in the summer is just a little more than half of what it was in the early 1980s — a result of the Arctic warming far faster than the rest of the planet — perhaps as much as four times faster, according to one NASA scientist.

As you will hear on this week's episode of Quirks & Quarks, scientists are studying Canada's glaciers, gleaning information about the current and past climate, volcanic eruptions — even forest fires — tracing changes over very long time periods. Ice is an invaluable archive of past climate data, which is why scientists are making the effort to study it, and even preserve samples of it, before it disappears. 

Greenland has already lost nearly four trillion tonnes of ice since the 1990s, and the trend is expected to continue. The loss of glacial ice will affect river flows around the world and contribute to sea-level rise. The loss of sea ice will change the temperature and biology of the Arctic Ocean.

Seeing for myself how much ice has been lost in only 14 years, I wonder if we are among the last generations to see many of these magnificent frozen rivers.

WATCH | CBC meteorologist Christy Climenhaga explores the state of Canada's glaciers.