Climate Change and Forest Fires in Canada

M.D. Flannigan, Canadian Forest Service, Canada; mike.flannigan@nrcn.gc.ca,

Fire is the major stand-renewing agent for much of the Canadian forest, and greatly influences the structure and function of boreal ecosystems from regeneration through mortality. Current estimates are that an average of 9000 forest fires burn 2.5 million hectares annually in Canada. There is a growing global awareness of the importance and vulnerability of Canadian forests to projected future climate change. Fire activity is strongly influenced by four factors – weather/climate, vegetation(fuels), natural ignition agents and humans. Climate and weather are strongly linked to fire activity which suggests that the fire regime will respond rapidly to changes in climate. Global atmospheric and oceanic dynamics play a major role in Canadian fire activity. Recent results suggest that area burned by fire is related to temperature and fuel moisture. The climate of the northern hemisphere has been warming due to an influx of radiatively active gases (carbon dioxide, methane etc.) as a result of human activities. This altered climate, modelled by General Circulation Models (GCMs), indicates a profound impact on fire activity in Canada. Recent results using GCMs suggest that in many regions fire weather/fire danger conditions will be more severe, area burned will increase, people-caused and lightning-caused ignitions will increase, fire seasons will be longer and the intensity and severity of fires will increase. Changes in fire activity as a result of climate change could have a greater and more immediate impact on vegetation distribution and abundance as compared to the direct impact of climate change.