This project was a collaborative effort with the Northern Climate Exchange at Yukon College to determine projections of future climate change in the area covered by the Atlin-Taku Land Use Plan in northern British Columbia.
Of particular concern for the Atlin-Taku region is the limited number of transportation links in the area, which could be impeded by changes in snowfall during winter or by an increased risk of forest fire in summer. Additionally, a run-of-river power production facility was recently constructed at Pine Creek to supply Atlin with electricity. Such facilities rely on sustained water levels so future changes in the regional hydrology could affect the facility’s ability to generate electricity, possibly forcing a return to diesel generators as a source of power in the region.
Methods
Simulations from three different global climate models (GCMs) driven with standard greenhouse gas emissions scenarios were used to determine projected future climate impacts. The projected climate for the 2050s (2041-2070) relative to a historical baseline (1961-1990) was shown at high resolution using an elevation correction method based on PRISM and ClimateWNA.
In addition to the standard emissions scenarios, five other emissions trajectories comprising both higher-intensity emissions and emissions reduction scenarios were analyzed using the University of Victoria Earth System Climate Model.
The impacts of future climate change were identified in terms of ecosystem effects, specifically in the shifts from one biogeoclimatic zone to another due to changes in such parameters as Growing Degree Days (GDD), Frost Free Days (FFD) and the Summer Heat to Moisture Index (SHMI).
Results
Historical temperature and precipitation records for the Atlin-Taku region supplied by Environment Canada’s CANGRID reveal that some climate change has already occurred during the period 1951-2007. These changes consist of statistically significant increases in mean annual temperature (0.2°C to 0.3°C per decade) and increases in mean annual precipitation (5% per decade) that vary both by season and location.
Analysis of projections from the full range of emissions scenarios indicate that the Atlin-Taku region will likely experience between 1.7°C and 2.7°C of warming by the middle of the 21st century, at least a 1.0°C increase even if net global greenhouse gas emissions are reduced to zero by 2050. Looking further into the future, the region could experience mean annual temperature increases of up to 6.0°C by 2100 and 9.0°C by 2200 under the highest-intensity emissions scenarios. The maps in Figures 1 and 2 provide an illustration of how projected temperature changes for the 2050s might manifest in the Atlin region.
Accompanying this future warming is a shift in precipitation type from snow to rain. Mean annual snowfall is projected to decrease by up to 40% by 2100. The combined temperature and precipitation increases lead to increases in GDD, FFD and SHMI, resulting in reduced alpine vegetation and a shift to warmer biogeoclimatic zones in the inland portions of the Atlin-Taku region.
For all projected increases, climate variability in the form of the El Niño/La Niña Southern Oscillation and the Pacific Decadal Oscillation will act to moderate or enhance the changes, depending on their phases.
Figure 1: Map showing the historical (1961-1990) baseline using PRISM data.
Figure 2: Map showing the future projected (2041-2070) mean annual temperatures for the area covered by the Atlin-Taku Land Use Plan using CGCM3 A2 Run 4.
Results from this project have been used to inform the design and implementation phases of the Atlin-Taku Regional Land Use Plan.
Acknowledgements
- Northern Climate Exchange, Yukon College
- Canadian Parks and Wilderness Society – British Columbia chapter (CPAWS-BC)
- Johnny Mikes and Chloe O'Loughlin (CPAWS-BC)
- Jim Pojar, Claudia Howers, Gregory Kehm, Juri Peepre, Scott McNay (Impacts Researchers)
- Dr. Shawn Marshall (University of Calgary), reviewer