Climate Change and Early Warning Systems for Wildland Fire - Reducing Disaster: Early Warning Systems for Climate Change - page 124

Shindell 2010 ). In terms of fi re severity and fi re intensity, a review of global research
papers showed mixed results in different regions (Flannigan et al. 2009a ). In the
boreal forest region, which represents about one-third of global forest cover, fi re
records document increased fi re activity in recent decades (Stocks et al. 2003 ;
Kasischke and Turetsky 2006 ) due to increased temperature (Westerling et al. 2006 ).
Under current climate change scenarios, global temperature increase is expected to
be greatest at northern high latitudes (IPCC 2007 ). For that reason, the boreal forest
region is anticipated to experience the earliest and greatest increases in wildland fi re
activity under future climate change.
Box 7.1 Fire, Weather, and Climate Change
There are four general factors affecting wildland fi re activity over a region:
1. Fuel - factors affecting fl ammability such as vegetation type (grass, shrub,
tree species), amount, moisture, and continuity (or distribution - both hori-
zontal and vertical) of fuel
2. Weather - temperature, rainfall, atmospheric moisture, wind speed, solar
radiation, atmospheric stability, upper atmospheric patterns (e.g., blocking
upper atmospheric ridges) directly affecting fuel moisture content, and
ability for fi re to spread
3. Ignitions - human and lightning
4. People - as a fuel modifi er (reducing fuel loads by clearing or burning;
planting new vegetation), and the primary source for identifying risk
(homes and communities located in the wildland-urban interface) as well
as conducting fi re management activities
Weather, in addition to being a key factor, also infl uences the fuel factor via
fuel moisture and the ignition factor through lightning activity. Climate
change will result in changes to the day-to-day weather and, in particular,
extremes; this is critical to wildland fi re as much of the area burned occurs
during relatively short periods of extreme fi re weather. A warmer world will
likely have more fi re and longer fi re seasons at higher latitudes; more light-
ning activity will lead to more lightning-caused fi res; and lastly, increased
evapotranspiration will lead to drier fuels unless there are signifi cant increases
in precipitation. Drier fuels will make it easier for fi res to ignite and spread.
In the most recent study of future global wildland fi re (Flannigan et al. 2013 ), the
potential infl uence of climate change on fi re season length and fi re season severity
was examined by comparing three General Circulation Models (GCMs) and three
possible emission scenarios (nine GCM-emission scenario combinations).
The GCMs used in the study were: (1) THE CGCM3.1 from the Canadian Centre for
Climate Modelling and Analysis, (2) the HadCM3 from the Hadley Centre
for Climate Prediction in the United Kingdom, and (3) the IPSL-CM4 from France.