Whitehorse Climate Change Adaptation Plan - Yukon College

difficult to discern. Furthermore, some data from recent decades has been lost. Non-parametric
trend analysis (which avoids biases associated with missing data) demonstrates that there
has been a trend towards decreasing winter precipitation. The trends for temperature and
precipitation are provided in Table 2.
Table 2. Climatic trends for the Whitehorse region.
Flow data is available for the Yukon River at Whitehorse. Warming trends and the melting of
those glaciers which feed the Upper Yukon Basin, have increased lake levels in the drainage
system above Whitehorse, but have not resulted in appreciable increase in overall annual flow
of the Yukon River through Whitehorse. Seasonal variation in flow has changed, but this is most
likely the result of hydrological control systems operated by Yukon Energy and not to a change in
the climate system. Flooding is not typically associated with peak flow in summer, but is instead
related to both freeze up (and ice damming) and spring melt (especially in heavy snow years
with rapid melt onset).
Standard meteorological data show a decreasing trend for wind at Whitehorse. Conversely, more
detailed research using weather balloons show a clear increase in wind. This contradiction is
likely explained by changes to the horizon as trees have matured or been replaced by buildings.
Both trees and buildings will break the wind and affect ground measurements of wind velocity.
At a range of elevations above sea level (from 1200 m to 2000 m) wind speeds have been
increasing at a rate of +0.2 m/s per decade (Pinard, 2007). At the same time, days have been
getting less cloudy at a rate of 1% per decade, but there is a lot of variability with cloudiness
from one year to the next.
Generally the trends show good agreement with projections (with the possible exception of
winter precipitation). Some of the trends appear to be outside the range of natural fluctuation
and thus relate to global climate change. However, we need to understand that natural
influences are also present and are mostly driven by the relationships to large-scale ocean
circulation patterns.
PROJECTED CLIMATE CONDITIONS FOR THE WHITEHORSE REGION
Whitehorse Climate Change Adaptation Plan
Climate Variable 1961 - 1990 2000 - 2009 Rate of Change
Annual temperature (°C) -1.1 ± 1.2 0.0 ± 0.9 0.4° C/decade
Winter temperature (°C) -15.9 ± 4.5 -13.2 ± 2.5 0.9° C/decade
Annual precipitation (mm) 268 ± 44 276 ± 46 1.6 mm/decade
Summer precipitation (mm) 109 ± 38 121 ± 33 2.3 mm/decade
Annual average flow (m3 /s) 244 ± 31 239 ± 30 0 m3 /s per decade
Frost-free days 144 ± 9 149 ± 8 2 days per decade
Climate projections for the region suggest a warmer, wetter Whitehorse. Projected climate
conditions were based on two time slices (2030 and 2050) and two standard IPCC global
emissions scenarios (B1 and A1B; as described in the Intergovernmental Panel on Climate
Change Special Report on Emissions Scenarios; Nakićenović, et al., 2000). The B1 scenario
projects moderate to low climate change over the next century. The A1B scenario indicates
medium to high climate change by 2100. These two scenarios were selected to provide a
reasonable range in possible shifts in temperature and precipitation by 2050. It should be
noted that while global efforts to mitigate climate change will affect how much change we are
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