By Lynn Martel
The Garibaldi glaciers are among the fastest
disappearing glaciers in the world, says Dr. Shawn Marshall, University of
Calgary associate professor in glaciology and climatology.
“The Coast Mountain glaciers are being
hammered — what’s happening in the Canadian Rockies times two,” Marshall
said. “That’s how much retreat is happening in the Coast Mountains.”
Marshall was
one of several speakers at a two-day workshop held in Banff Oct. 10
and 11, titled Climate Change and its Affects on the Alpine. Organized by the
Alpine Club of Canada as part of the club’s 2006 centennial celebrations, and
running in conjunction with the general assembly of the International
Mountaineering and Climbing Federation (UIAA), the workshop drew 40
participants from as far as Kimberley, Vancouver, Edmonton, Montreal and even
South Africa and the Netherlands.
“Glaciers in the Coast Mountains are really
vulnerable,” Marshall said. “Even a small change in temperature can change snow
to rain. Some have lost 70 per cent of their size in this century. The Helm,
Sentinel and the Garibaldi glaciers are among the most threatened in the world.
“There are many more glaciers scientists know
little or nothing about, he added. But they do know the glaciers are
disappearing.
“Scientists are witnessing profound changes in
glaciers around the world, and from what we understand, these changes can be
expected to continue and accelerate,” Marshall said. “Bigger icefields should
hang in for a while, but with smaller outlet glaciers, we can’t give a number.
Every glacier has its own story. Some pocket glaciers might melt back quickly,
then retreat into sheltered cirques that never see the sun, which could stall
their retreat. Others could disappear altogether.”
While scientists still have plenty of
questions about how much and how fast glaciers around the world are melting,
most agree on two things — glacial retreat is global, Marshall said, in
both mountain and polar regions, and humans have been instrumental in causing
those changes.
While western Canada’s glaciers aren’t
retreating as quickly as those in other mountain ranges, such as Russia’s
Caucasus, Peru’s Andes or Patagonia in Chile, Marshall said, there are very few
places in the world where increases in snow accumulation are sufficient to
offset warming temperatures and extend the life of glaciers, and Canada is not
on the short list.
In order to be sustainable, a glacier needs to
retain 60 per cent of the snow that falls on it each season. In recent years,
many of western Canada’s glaciers have none of their winter snowfall left by
the end of the season, leaving a surface of bare glacial ice that collects
dirt, including particles from forest fires. The darker surface then absorbs
increased sunlight, which in turn accelerates melting.
“If this is the new reality, these glaciers
will be removed — gone from our landscape,” Marshall said.
While a shortened summer glacier ski season
can spell negative effects for recreation-based economies, the picture is even
less attractive in terms of water, said workshop speaker Dr. David Sauchyn, chief
scientist at the Prairie Adaptation Research Collaborative at the University of
Regina, and member of the United Nations Intergovernmental Panel on Climate
Change.
“The biggest issue is water — where does
the water come from?” Sauchyn said. “The eastern slope of the Rockies is the
most critical landscape for all the prairie provinces — Saskatchewan,
Manitoba and Alberta. Nearly the entire population of the prairie provinces
gets its water from the Rockies.”
At the lower elevations,
where extensive and reliable weather records have been kept for the past
century, the snowpack has decreased 20 to 25 per cent over the last 20 years.
“At the lower elevations
in the Rocky Mountains, historically the snowpack built up through the winter.
It’s not doing that now,” Sauchyn said.
“The winter is
quite a bit warmer than it was a few decades ago. The most serious consequence
of losing our winter is losing our snow. The disadvantage of rain is that when
it falls, it runs off. Snow and ice are reliable sources of water. Believe it
or not, there are advantages to having a cold winter.”
Those include cold winter temperatures killing
off harmful pests, such as mosquitoes carrying West Nile virus and pine
beetles, which are currently infesting forests across western North America.
While from some
perspectives
Canada is seen as a nation that stands to
benefit the most as global temperatures rise, that’s an oversimplification,
Sauchyn said.
The same higher
temperatures that lead to a longer growing season, will also likely
lead to water shortages.
“The picture may appear rosy, but only to a
point,” said Sauchyn, o
ne of
dozens of authors of the National Assessment on Climate Change, to be released
in 2007
. “The growing season will be warmer and longer,
but the bad news is more water will be stored in the air than in the ground.
Water scarcity could constrain economic growth.”
Not to mention the ability of ski hills to
make snow at lower elevations, he added.
One reason scientists don’t know how fast
western Canada’s glaciers are melting is that while continuous and
comprehensive research has been conducted at lower elevations, detailed
scientific studies have been conducted in the high alpine for only the past 40
years.
“There are thousands of glaciers in Canada,
more than any other country in the world, but only a handful that have been
scientifically studied, and that didn’t really start until the mid 1960s,”
Marshall said.
Ski hills record snowfalls throughout B.C. and
Alberta, and avalanche researchers annually compile high quality records in
Glacier National Park, where members of the Vaux family collected comprehensive
data in the late 1800s and early 1900s, but all of that information is
seasonal.
“We don’t have high quality, continuous,
reliable, quality controlled information,” Marshall said.
Despite the shortage of information on snow
levels in the high alpine — due to a combination of factors, including
funding and the logistics of accessing research plots in the high alpine for
necessary regular maintenance — among the scientific community, one thing
is no longer being debated.
“There is no more uncertainty about climate change than there is about economics,” Sauchyn said. “But somehow scientists are held up to a higher standard. But the debate is over. The climate is changing, and it’s very clear that we are at least partially responsible.”