The Thwaites Glacier in Antarctica is seen in this undated NASA image. Vast glaciers in West Antarctica seem to be locked in an irreversible thaw linked to global warming that may push up sea levels for centuries, scientists said on May 12, 2014. Six glac
The Thwaites Glacier in Antarctica is seen in this undated NASA image. Vast glaciers in West Antarctica seem to be locked in an irreversible thaw linked to global warming that may push up sea levels for centuries, scientists said on May 12, 2014. Six glaciers including the Thwaites Glacier, eaten away from below by a warming of sea waters around the frozen continent, were flowing fast into the Amundsen Sea, according to the report based partly on satellite radar measurements from 1992 to 2011. Reuters/NASA

Canada's Athabasca Glacier, the most visited glacier in North America, is losing five metres (16 feet) of ice per year that scientists forecast the immediate next generation of Canadians and tourists won't be able to see and enjoy them anymore.

The largest of six ice sheets that comprise the Columbia Icefield in Jasper National Park, the Athabasca Glacier receives seven metres of snowfall per year, John Wilmshurst, Jasper National Park's resource conservation manager, said. But such amount is nothing compared to the rapid shrinking of the glacier in the past 150 years.

"It's astonishing," Wilmshurst told The Canadian Press. "Every year we drive stakes five metres deep into the glacier in the fall. We have to return and re-drill them in mid-summer because a lot of those stakes on the Athabasca Glacier, the one that a lot of people go visit, will be lying flat on the ice at that time.

He pointed out that more than a century ago, markers have been placed on the 300-metre deep Glacier to monitor its ice activity. Readings from these markers have shown that the toe of Athabasca has receded by at least 1.5 kilometres, which has opened up to a landscape filled with rock and gravel instead of ice and snow cover.

Apart from the receding activity, the glacier has also been found to be becoming shallower which is "mind boggling," Bob Sandford, chairman of the Canadian Partnership Initiative of the UN Water for Life Decade, said.

"I first wrote a tourist book on the Columbia Icefields in 1994 and it was generally held that it was somewhere around 325 square kilometres. That icefield now is calculated to be about 220 square kilometres," he said.

"Even though this year we will have had a fairly substantial snow year, what we're finding is that, even with substantial snow years, the summers are warm enough and the fall is prolonged enough that all of that snow goes and we're still losing five metres," Sandford said. "That gives you an indication of how rapidly things are changing."

Absolutely the glacier will be gone. "Not within my lifetime, probably, but maybe within my children's lifetime," Wilmshurst said.

"It is hard to know in the long term what climate cycles mean to people. It does mean we should be preparing for drier conditions in the future. I think long term it's not good news at all," he said.

Take a look at Athabasca Glacier here.