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Forest fires in Canada's boreal forests burn an average of 2.5
million hectares annually. Fire is a natural and necessary force,
shaping the landscape and ensuring the healthy growth of new forests.
However, climate warming can bring more frequent and severe fires,
shorter growth periods between fires, proportionally younger stands,
and a decrease in the carbon storage of northern Canadian forests.
Method
Climate simulations, which were generated from four Global
General Circulation Models (GCM), were used to project forest
fire danger levels with relation to global warming.
This map shows the change in forest fire severity levels across
Canada from 1980 to 1989 to 2050 to 2059, and to 2090 to 2099, based
on the most recent Canadian GCM - Coupled
Global Circulation Model 2 (CGCM2). The Seasonal Severity Rating
(SSR) is a measure of fire danger conditions over a complete fire
season. The SSR
is developed by averaging daily values over the season. The scale
shown is relative, with values above 6 being extreme. A real value
of zero is only possible in remote cold regions where no fire danger
exists in the summer months.
Interpretation
The map shows large increases in the area extent of extreme fire
danger and a lengthening of the fire season.
The map layers for the three time periods demonstrate the same
general spatial pattern in terms of the fire severity level. Historically,
the regions having the most significant forest fire activity in
Canada have been in west-central Canada. However, the areas with
high sensitivity to forest fires are expected to expand geographically
through time.
As shown in the layer for the period 1980 to 1989, the areas with
the highest forest fire danger levels were in the southern Prairies,
southern Ontario and the north-western parts of the Northwest Territories.
For the period 2050 to 2059, the projected distribution of forest
fire severity levels are similar to the 1980 to 1989 period, with
a general geographic expansion outward from the former distribution.
The areas with high severity ratings are projected to expand into
the central Prairies, southern British Columbia and south-western
Yukon.
For the period 2090 to 2099, the areas sensitive to forest fires
are further expanded into the central and northern parts of the
Prairies, southern and eastern British Columbia, southern-central
Yukon, and north-western Ontario.
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