With temperatures spiking 20 degrees over a three-hour time span and other La Nińa events having entertained Bow Valley residents all winter long, many people are likely wondering how the weather of the 2010/11 winter season might relate to climate change.
Globally, however, populations have coped with increased frequency of droughts and floods and other climatic challenges over recent months.
“With all that’s been happening down here, in the eastern high Arctic temperatures all through December and January were 20 degrees higher than normal,” Bob Sandford said.
With those and related events in mind, about 75 people gathered at the Canmore Collegiate High School Theatre last Thursday (April 14) for a presentation titled Storm Warning: Emerging Issues in Water & Climate Science.
Moderated by the director of the University of Calgary’s Biogeoscience Institute, Edward Johnson, the presentation featured talks by U of C glaciologist candidate Jocelyn Hirose, and Sandford, EPCOR Chair of the United Nations Water for Life Decade in Canada, outlining climate impacts on water security globally and in the Canadian West.
And, as a result of conditions that public servants not speak publicly during a federal election, Sandford also spoke on behalf of Mike Demuth, head of the Geological Survey of Canada’s glaciology division, whose presentation outlined the long-term goals and importance of research on the Columbia Icefield being conducted in partnership with Parks Canada.
“The major risk from climate warming is a change in the availability of water resources, including the amount and timing between seasons, sub-basins and years,” Sandford said. “The dramatic retreat of glaciers in the Rocky Mountains already reflects changes in the annual snowpack over time.”
According to a paper soon to be published in the Canadian Water Resources Journal and prepared by U of C glaciologist Shawn Marshall and colleagues, 85 per cent of the volume of the Rockies’ eastern slope glaciers is likely to disappear by the end of this century as a result of climate change.
Marshall’s conclusions are based on research conducted on Peyto Glacier, which feeds into Peyto Lake, located 40 kilometres north of Lake Louise and one of the Icefields Parkway’s most popular tourist attractions, and which happens to be one of only 39 glaciers world-wide that has been continuously studied for more than 30 years.
“Research conducted on the world’s “reference glaciers” indicates a cumulative global loss in glacial mass of 20 per cent between 1945 and 2005, which suggests that a great deal of the world’s ice has already become water,” Sandford said.
Currently covering an area of about 12 square kilometres, Peyto Glacier has lost 70 per cent of its volume in the last 100 years. While there are seasonal fluctuations, overall the winter snow depth and duration of cover have been declining since the 1970s. If current temperature trends persist, Bow Glacier, headwaters of the Bow River, could completely disappear in about 53 years; the ice at the headwaters of the North Saskatchewan could melt away by 2170 and the glacial sources of the Athabasca River could disappear in 83 years.
Even if the Earth’s climate were to be stabilized at current warming levels and glacial melting was to continue at the rates of recent decades, the overall mass balance loss of the Rockies glacial volume would still be 55 to 60 per cent.
The effects of a single La Nińa winter are not enough to halt overall glacial loss, Sandford said, adding that because of limited data Marshall is concerned that his average estimates of current glacial volume may be too low.
“Dr. Marshall has made it very clear to the scientific community that these were estimates only based on ‘first-order’ calculations that have not been verified by more accurate measures of the volume of ice that actually exists in Alberta’s Rockies,” Sandford said.
While most literature, including Sandford’s own, ascribes an area of 325 square kilometres to the Columbia Icefield, Marshall’s calculations estimate its area to be closer to 223 square kilometres – more than 30 per cent smaller than originally thought.
Until now, North American attention has focussed on the Montana’s Glacier National Park, where 113 of the 150 glaciers that existed in 1860 have vanished. Research conducted by the Geological Survey of Canada and the IP3 and Western Canadian Cryospheric Research networks show that Canada may have lost 300 glaciers in the Canadian Rockies between 1920 and 2005, with 150 disappearing between 1920 and 1985.
“The other 150 glaciers appear to have disappeared into thin air in the 20 years between 1985 and 2005,” Sandford said. “This suggests that our losses appear to be accelerating.”
Now in its second year, a study on the Columbia Icefield led by Demuth is conducting an airborne light penetration – LIDAR – survey to determine the subsurface topography of the Columbia, and also the exact volume of ice it contains.
“In my opinion, the Columbia Icefield Research Initiative may well be the most important scientific research project undertaken in a Canadian national park since the national park system was created 125 years ago,” Sandford said. “This research is already beginning to clarify exactly how much glaciers actually contribute at any given time of the year to streamflow relative to rainfall and snowmelt. Perhaps more importantly, this research clearly demonstrates the climate signal in recent hydrological trends.”
La Nińa years such the 2010/11 one are just blips in the larger climate cycle, he continued, adding that they are projected to occur less frequently in the future.
“Because of climate change, the hydrology of our entire country is on the move,” Sandford said. “At the moment, we simply don’t know how much faster warming may be occurring at higher altitudes because we have few measures and no baseline for comparison.
“This landmark project will provide the beginning of that baseline, not just for determining future water supply, but for understanding other climate impacts we might face throughout Western North America.”
