That's all it will take to completely alter an entire ecosystem that survives and even thrives in the most Canadian of natural environments—snow.
The persistent diminishing of winter in the Northern Hemisphere was the focus of a recent Canmore presentation by three of Canada's most respected climate change authorities.
"Not only is snow one of the most beautiful and physically complex natural phenomena, it is the home of many plants and animals, the food source for many more and the provider of water for the alpine summer and for rivers that drain the mountains to provide water to the parched Prairies," said Dr. John Pomeroy, head of hydrology for the University of Saskatchewan.
Snow provides habitat for ungulates and other mammals and birds on the surface, while plants and small mammals take advantage of snow's insulating qualities below.
"The deeper you go in the snow, the hotter it is," Pomeroy said. "If you're a vole, that's a nice, warm place to be."
But snow also harbours countless lesser-known species, explained Bob Sandford, Canadian chair of the UN's Water for Life Decade initiative.
"Snow is a unique environment," Sandford said. "Whole ecoystems are known to exist within the wilderness of the nivean world. Some of these ecosystems — those found on glaciers — are among the oldest to exist on Earth. They are also among the most endangered."
As many as 466 species of microorganisms live in snow, including 77 fungi, 35 bacteria and numerous algae. Among the best known cryophiles (creatures that survive at or below water's freezing point) are red algae, or "watermelon snow". Some researchers think these organisms can be traced as far back as the period immediately preceding the Cambrian explosion of life represented in the Burgess Shale.
"Glacial ecology is still very much in its pioneering stage," Sandford said. "Cold-adapted microorganisms have considerable potential in biotechnological applications as wide ranging as waste treatment at cold temperatures, enzymology, the food industry, medicine and in environmental bioremediation."
But with temperatures warming and glaciers diminishing the world over, these organisms might disappear before some are even discovered.
"It would be a tragedy to lose our psychrophilic ecosystems before we even knew they existed," Sandford said.
Since global observations began in the late 1960s, a 10 per cent reduction in snow-covered area in springtime in the North Hemisphere has been recorded. Over the course of the 20th century, the duration of ice cover in rivers and lakes in Canada's high and middle latitudes decreased by two weeks. Worldwide, glaciers have declined steadily for the past century.
In the Canadian Rockies alone, as many as 300 glaciers could have been lost between 1920 and 2005.
Not just shrinking back, glaciers are thinning and losing volume all around. After the Rockies' plentiful spring 2011 snowfalls, University of Calgary glaciologist Dr. Shawn Marshall said he had hoped he might witness a positive mass-balance occurrence on Kananaskis Country's Haig Glacier. By summer's end, however, all the winter snow had melted, plus a portion of glacier ice.
"I really thought it might lead to a positive mass balance, but it didn't quite make it," Marshall said. "Not just here; Greenland is weighing less every year. There is a redistribution of mass of the global system taking place."
Beyond habitat and water storage, glacier loss has other consequences. Known as albedo, the occurrence of snow and ice reflecting sunlight back into the atmosphere is lowering, increasing the absorption of solar radiation which in turn further reduces snow and ice cover.
The ability to insulate six times more effectively than the equivalent depth of soil, deep snow permits the growing of grain crops such as winter wheat. Snow acts as a reservoir, storing water the way a dam does for gradual release downstream through spring and summer.
"There is not enough money in the world to build all the dams that would be required to store all the water that the winter snowpack does for later release into streams and rivers," Sandford said. "Cold provides this invaluable service for free."
Over recent decades researchers have recorded a 40 per cent decrease in thickness of Arctic sea ice. It is estimated that the loss of northern sea ice will cause as much warming as can be attributed to 70 per cent of the carbon dioxide presently in the Earth's atmosphere.
Add to that, widespread degradation of permafrost due to rising temperatures across the north is releasing large volumes of trapped methane into the atmosphere. Though it doesn't remain in the atmosphere as long, methane is 24 times more potent a greenhouse gas than carbon dioxide.
"The thresholds at which such changes might occur are among the most troubling unknowns in climate science," Sandford said. "The mountain west is in the midst of significant change."
The fact that Canadians remain unprepared, however, is a real problem.
"The water security of western Canada is predicated on the preservation of the natural flows and storage of mountain snow, ice and water," Pomeroy said.
"This water security controls our natural ecosystems and our ability to provide communities, food and energy throughout western Canada. We risk everything by losing this water security."
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