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UVic researchers use the growth rings of ancient
trees to track B.C. climate over thousands of years.
Glacier researchers join forces
The University of Victoria is one of
seven western universities that have
formed the new Glacier Research Network,
a five-year research initiative that
will improve our understanding of how
glaciers respond to climate change.
UVic geographer Dan Smith leads
a section of the network focused on
understanding climate changes over
the last 400 years in the Mount Waddington
area in southwestern B.C.
The Glacier Research Network is
led by the University of Northern British
Columbia. In addition to Smith,
it involves researchers from four other
Canadian universities, the University
of Washington, federal and provincial
governments, BC Hydro, and the
Columbia Basin Trust.
The network is funded by the Canadian
Foundation for Climate and
Atmospheric Sciences (CFCAS). For
more information visit http://wc2n.
unbc.ca/.
by Suzanne Connell
When it comes to understanding
climate change, University of Victoria
geographer Dan Smith has found
that ancient trees have an important
story to tell.
Smith and his student team are
using forensic-like research to study
the growth rings of trees buried long
ago by advancing glaciers. All over
western North America glaciers are
melting at a staggering rate, exposing
trees that haven’t seen the light of day
for thousands of years. These trees
provide Smith’s team with detailed
information about the movement of
glaciers over time and the associated
changes in climate.
“We’re looking back thousands of
years to get an idea of how glaciers
in B.C. have advanced and retreated
and the conditions that have led to
these changes,” says Smith. “Ancient
tree ring information helps us to
predict what our glaciers may look
like in the future, and to assess what
the impact of their diminished size
will be.”
Understanding the movement
of glaciers provides clues to how
they respond to long-term warming
and cooling trends. Glaciers are also
an important provincial resource.
They supply rivers with fresh water,
which nourishes ecosystems, fills
our reservoirs and provides us with
hydroelectric power.
Since 1920, the retreat of glaciers
in the coastal mountains has rapidly
accelerated. Many of these glaciers
are expected to vanish completely
by 2100.
Every summer Smith and his
team travel to remote parts of B.C.’s
coastal mountains north of Vancouver
and set up camp next to glaciers.
Smith has studied more than 100
glacier sites in this region over the
last five years, most of them accessible
only by helicopter.
Once the team arrives, they search
for trees left behind after the glaciers
melt and slice off sections of logs with
a chainsaw. Back at UVic, a measuring
device records an image of the
log’s tree ring profile, and computer
analysis is used to detect the impact
of climate changes on tree growth.
Trees produce a layer of wood
every year of their lives. Researchers
count the number of rings to
determine a tree’s age, and measure
the width of the rings to learn rates
of growth in the past.
“These trees contain hundreds
of annual growth rings, which give
us a history of their life before they
were killed by the glacier,” explains
Smith. “By matching that record to
the records of living trees in the area
we can track how the climate has
changed year-to-year over thousands
of years.”
Smith has found that the glaciers
in the coastal mountain range have
receded and advanced fairly consistently
over the last few thousand
years. A major period of glacier expansion
that began 3,000 years ago
is now ending.
“Despite the fact that most of the
glaciers are receding we shouldn’t assume
this is a major event, especially
since 8,000 years ago none of these
glaciers even existed.”
However, studies conducted by
Smith and others have convinced
him that humans have played a major
role in altering global climate. “The
climate on this planet is changing
and the evidence is overwhelming
that we’re responsible for it. We can’t
negate our influence; we just don’t
yet know its ultimate impact.”
Funders for Smith’s work include
the Natural Sciences and
Engineering Research Council, the
Inter-American Institute for Global
Change Research, and the Canadian
Foundation for Climate and Atmospheric
Sciences.
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