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Potential Impacts of Climate Change on Fire Regimes B. Amiro, E. Bosch, M. Flannigan, K. Hirsch, V. Kafka, K. Logan, D. Martell, J. Mason, M. Parisien, W. Skinner, B. Stocks, B. Todd, M. Wotton Presentation at the Natural Disturbance and Forest Management Workshop - March 5-7, 2001, Edmonton, AB Natural Resources Canada Ressources naturelles CanadaCanadian Forest Service Service canadien des forêts
Presentation Outline 1. Introduction and Background 2. Projected climatic changes and the possible influences on fire regimes 3. Implications for SFM in Canada 4. Questions
Canadian Fire Situation in the Recent Past • 10,000 fires per year • 0.3-7.5 million ha burned per year • fire management costs ~500 million annually • large fires dominate (3% > 200 ha = 97% Area Burned) Fires larger than 200 ha - 1980-89
Percent Area Burned by Eco-Region Annual Area Burned (%) 1959-99
Is Fire Activity Increasing? ? Higher data reliability Lower data reliability
Fire Suppression is a approaching its Physical/Economic Limits Level of Protection Analysis for Ontario 2-3% of wildfires will continue to escape initial attack
Fire has significant social, economic, and ecological effects that need to be balanced as part of SFM Fire is and will continue to be a dominant feature in shaping the landscape A changing climate creates considerable uncertainty about natural disturbances in the future
General Climate Change Projections • GCMs project 0.8 – 3.50 C increase in global mean temperature by 2100 • Greatest increases will be at high latitudes, over land and winter/spring • Projected increases in extreme weather - regional scale • These models are future estimates or scenarios - not predictions • Numerous cavets but the models are the best tools currently available.
Potential Increases in Extreme Fire Danger Influence fire intensity, severity, size GCM Analyses - SSR Ratio 3xCO2/1xCO2
Potential Changes to Fire Season Length RCM - 2xCO2/1xCO2 Fire season will start earlier in the spring and extend longer in the fall
Potential Changes to Fire Ignition Uncertain at this point in time - Increased cloud to ground lightning is possible - Significant rise in lightning fires in the US - Research has just been initiated in Canada - Depends on human activity, landscape fragmentation, fire management policy/practices, etc.
Potential Changes to Fire Danger - SSR Ratio RCM - SSR Ratio 2xCO2/1xCO2 Generally increasing but spatial variability Highest increases are in most active fire areas
Potential Changes to Fire Intensity RCM - SSR Ratio 3xCO2/1xCO2 Central Saskatchewan HFI Ratio 3x/1x CO2 0.0 - 0.2 0.2 - 0.4 0.4 - 0.6 0.6 - 0.8 0.8 - 1.0 1.0 - 1.2 1.2 - 1.4 1.4 - 1.6 1.6 - 1.8 1.8 - 2.0 2.0 - 3.0 3.0 + No fuel This will influence the type of fire (more crowning), depth of burn, reduce suppression effectiveness, and may lead to larger sized fires.
Accelerate Vegetation Changes • Could profoundly influence • age structure of the forest, • forest composition, • migration of species and extinction
Interaction with Other Disturbances • Spruce budworm • Forest tent caterpillar • Mountain pine beetle
Effects on Canada’s Carbon Budget - Annual emissions from fires can be from 2-75% of the fossil fuel emissions - Flip Canada from being a carbon sink to a source - Negative feedback loop
Increased impacts on public health and safety Greater threat to life and property • Smoke effects on air quality
Competitor for Forest Resources • Wood fibre • Recreational areas • Impacts on water quality, wildlife, etc.
Public and Industry will have to Adapt Local Scale • Protection of values • communities • key recreational areas • infrastructure Regional Scale • Fire-Smart Forest Management • e.g., minimize impact on timber supply in the “managed forest” National Scale • Cannot mitigate impacts on the whole boreal forest • monitor impacts
Summary • Natural role of fire is critical to maintain the boreal forest zone • Fire exclusion is neither economically possible nor ecologically desirable • GCMs and RCMs project increases in • fire season length • extreme fire weather/danger • fire intensity, severity, crowning • Facing more area burned and fire impacts • Fire is a catalyst for vegetation change • Forest fires are an important part of Canada’s carbon budget • Adaptation strategies are required
Thank You Natural Resources Canada Ressources naturelles CanadaCanadian Forest Service Service canadien des forêts