Researchers say they’ve found a link between global warming and an increase in the size of forest fires within Canada’s Boreal region.
“Control of the multimillennial wildfire size in boreal North America by spring climatic conditions” was published December 3, 2012 on the website for Proceedings of the National Academy of Sciences (PNAS).
The Canadian researchers studied carbon found in the sediments of lakes in the coniferous Boreal forest of eastern North America. Researchers then drew a regional history of fire frequency, biomass burned and the average size of fires in the study area.
“A progressive increase of fire size was recorded, which is most likely related to a gradual increase in temperatures during the spring fire season,” the Boreal study states. “Continuing climatic warming could lead to a change in the fire regime toward larger spring wildfires in eastern Boreal North America.”
Researchers found that while the number of fires and the biomass burned have actually decreased over the last 3,000 years, the area covered by the fires has increased.
The research team says it has demonstrated that fire size correlates with average spring temperatures. These temperatures are about one degree Celsius higher than they were 5,000 years ago, because of increased spring insolation (a measure of solar radiation energy). According to the researchers, this slight increase in temperature is still sufficient to increase the average size of spring wildfires by a factor of three.
Larger spring fires can be expected in Boreal regions in the coming years, the Boreal study suggests. These wildfires threaten the carbon sink of forest ecosystems and could contribute to global warming.
For a list of the 10 researchers who participated in the Boreal study, and to read the study itself, please click here.