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Mountain News: Shrinking glaciers a concern



GOLDEN, B.C. - Professors have been out to the towns on both sides of the Continental Divide in Canada recently to talk about the shrinking of glaciers. It is, they say, a serious challenge, as the hydrological cycle that local communities have come to depend upon will be changing.

But ice in both places has been shrinking - with much more recession likely. At a forum in Golden, B.C., Kindy Gosal, director of water and environment for the Columbia Basin Trust, explained that the glaciers matter because "they are our banks and reserves of water. And really, we don't have a good idea what's happened in those bank accounts of water and what the future impacts might be as those bank accounts become depleted, or how fast we're depleting their funds.

The greater concentration of glaciers can be found in the Columbia River Basin. Compared to the glaciers on the east side of the Continental Divide, near Jasper and Banff, there is twice as much ice coverage, in a smaller geographic area. Upstream from Golden, 287 glaciers in the catchments of the Columbia and Kicking Horse Rivers cover 247 square kilometres.

Computer models suggest the disappearance of many glaciers during this century, although not all. Shawn Marshall, from the University of Calgary, said he guessed "by the end of the century there will still be glaciers."

But if glaciers remain, the flows will be very different. The loss will be little noted much of the year. The most pertinent time is late summer, when glaciers contribute as much as 12 to 13 per cent of streamflow, said John Pomeroy, a professor at the University of Saskatchewan.

In Alberta, the Columbia Icefield has been shrinking since at least 1843, near the end of what was called the Little Ice Age, a cooling period that lasted several hundred years.

But the shrinking, an average of 10 metres per year, has been accelerating, leaving tree stumps exposed that may have been covered for 8,000 years, notes the Rocky Mountain Outlook .

As in British Columbia, scientists say that having less water from melting glaciers in years ahead to augment the native river flows from snow and rain will create duress in late summer.

"Whatever the cause of these changes in glacier cover, they will have significant effects on the flow volumes, the season flow patterns, plus water temperatures and water quality, that will impact human activities downstream (irrigation, water supply and in some cases, power generation) and also on stream ecology," stated Dr. Brian Luckman, a geography professor at the University of Western Ontario who specializes in alpine environments and glacier fluctuations.