Canadian Arctic ice shelves have lost almost half their volume in the past six years, as part of an astonishing deterioration that an Ottawa researcher says is likely irreversible.

Derek Mueller, an assistant professor in Carleton University's Department of Geography and Environmental Studies, says the ice shelves are going through an unprecedented period of change.

"Really on a human timescale, six years is actually a long time," Mueller told CTV's Canada AM during a telephone interview from Ottawa on Wednesday morning.

"But on the scale of the thousands of years that these ice shelves are thought to have been in place, it is a massive change."

This summer alone, Canada's largest ice shelf split into two pieces and another is now nearly gone, tearing away some three billion tonnes of ice from the northern coastline.

Mueller said that researchers discovered the Arctic ice shelves more than 100 years ago, at a time when they were much larger than they are today.

While the ice shelves have faced warmer and cooler periods in the decades since, Mueller said they are now breaking down faster than ever before.

"This is a one-way process, it's already well underway. I fear that these ice shelves are basically gone," Mueller said.

Mueller said a warmer climate has helped create open water in portions of the ice shelves in recent years, which has contributed to their rapid decline.

He said the ice shelves are a natural wonder, which form a unique part of Canada's landscape.

"Beautiful rolling topography, beautiful meltwater lakes and unfortunately, it's on the way out," said Mueller.