WhiteCAP_Plan_01SEPT..

Northern Climate ExChange WhiteCAP Draft Plan
ground measurements of wind. 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% / 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 related to global climate change. However, we need to understand
that natural influences are also present, mostly driven by the relationships to large scale
ocean circulation patterns.
Table 4.1 Climatic Trends for the Whitehorse Region
Climate Variable 1961-1990 2000-2009 Rate of Change
Annual Temperature (°C) -1.1 ± 1.2°C 0.0 ± 0.9°C 0.4°C /decade
Winter Temperature (°C) -15.9 ± 4.5°C -13.2 ± 2.5°C 0.9°C /decade
Annual Precipitation (mm) 268 ± 44mm 276 ± 46mm 1.6mm/decade
Summer Precipitation (mm) 109 ± 38mm 121 ± 33mm 2.3mm/decade
Annual Average flow (m 3 /s) 244 ± 31 m 3 /s 239 ± 30 m 3 /s 0 m 3 /s/decade
Growing Degree Days
(5°C base)
991± 87 GDD 1062 ± 120 GDD 24 GDD/decade
4.2 Projected Climate Conditions for the Whitehorse Region (2041-2070)
65 maps were generated by SNAP to assess how climate change may affect the
Whitehorse area. The climate projections anticipate a warmer Whitehorse which
experiences increased precipitation. Projected climate conditions were based on two
time cuts (2030 and 2050) and two standard IPCC scenarios (B1 and A1B) 13 . The B1
scenario projects moderate to low climate change over the next century. The A1B
scenario anticipates 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. A more detailed explanation for the projections and all 65 maps are provided in
Appendix E. Details on the projected extension of the growing season based on changes
to the seasonal freeze-up and thaw dates for Whitehorse are presented in the same
appendix.
4.2.1 Temperature
Projected mean annual temperature and seasonal temperatures for the Whitehorse area
were estimated for 2030 and 2050. Annual and seasonal baseline temperatures are
compared to the projected temperatures in Table 4.2. The relative difference between
the projected and baseline temperature is provided in italics. Projected increases
indicate that warming will differ seasonally, and that winter period will experience the
most significant warming – increasing 3.3°C to 5.4°C.
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