ENVIRONMENTAL CHANGES IN THE SOUTHERN CANADIAN ROCKIES FROM MULTIPLETREE RING PROXIES
WATSON, EMMA (1); LUCKMAN, BRIAN (2); PEDERSON, GREG, (3); AND WILSON, ROB (4)
(1) Climate Research Branch, Meteorological Service of Canada, Environment Canada, Ontario,
Canada, (2) Department of Geography, University of Western Ontario, London Ontario, Canada,
(3) U.S. Geological Survey – Northern Rocky Mountain Science Center - Glacier Field Station,
Glacier National Park, West Glacier, MT, and Big Sky Institute – Montana State University,
Bozeman, MT, (4) School of Geosciences, Grant Institute, Edinburgh University, Edinburgh,
United Kingdom
The varied topography and landscapes of the Canadian west afford a unique opportunity to
sample and develop tree-ring chronologies sensitive to different climate conditions from within
close proximity. They also provide multiple sources of proxy climate data at varying timescales
and resolution. This has allowed the development of a detailed history of climate and
environmental changes for the region and in this paper we discuss selected results from this
research. Initial work throughout the Rockies led to the development of a glacial history spanning
the last millennium based on tree-ring dating, lichenometry and 14C dating. Though by its nature
incomplete, biased and censored the glacial record provides a framework against which more
continuous proxy records may be validated. Dendroclimatic studies have now allowed the
reconstruction of changes in precipitation and temperature in the central Canadian Rockies. We
also present more recent work which has sought to examine variability in streamflow. The broad
network of moisture and temperature sensitive chronologies has allowed us to begin studying
more complex variables that integrate seasonal changes in precipitation and temperature.
Winter, summer and net mass balance reconstructions have been developed for Peyto Glacier in
Banff National Park, Alberta. These records are 322 yrs in length and offer a continuous insight
into glacier variability over the LIA that was not available previously. The net mass balance
reconstructions correspond well with the dated moraine record for the central Canadian Rockies
and indicate that prolonged periods of both wet winters and cool summers are required for glacier
advance. Periods of positive net balance generally correspond with or proceed terminal moraine
development in the region in the early 1700s and mid-19th century. Cumulative net mass balance
for Peyto Glacier is consistently negative after 1883. These mass balance reconstructions can be
compared with similar records developed for Glacier National Park further south and thereby
begin to address broader questions on the timing and scale of glacier advances of the past 300
years throughout this portion of the Rocky Mountains.