New research indicates that the risk of severe wildfires is increasing worldwide, with some of the largest increases occurring in western Canada.
The research, conducted by Natural Resources Canada and published Thursday in the journal Nature, says higher temperatures and lower humidity are the biggest drivers of change.
“Our projections for the future show those same trends,” lead author Peyush Jane said. “We can expect hot weather to become more extreme.
“Future fires will burn longer and more intensely.”
Previous research has found that fire seasons are lengthening, with an associated increase in the amount of forest burned. Jain and his colleagues wanted to look at how severe fire risks might change with it.
They used a tool called the Fire Weather Index, a digital rating that uses temperature and precipitation information to assess the risk of out-of-control wildfires.
In Alberta, the Fire Weather Index 19 is considered very high. A fire outbreak under these conditions is likely to override efforts to put it out.
Over the years from 1979 to 2020, this indicator for the interior of British Columbia increased between 10 and 20 points.
Globally, the index rose by an average of 14 percent.
Last summer, extremely hot and dry weather pushed the fire hazard in British Columbia into uncharted territory — what fire officials described as “extremely severe.” Soon after, the village of Lytton was wiped out when a fire broke out.
“The intense fire weather has increased over large parts of the land,” Jain said. “There are certain regions where there are larger trends, such as western North America.”
The researchers found a strong relationship between extreme fire weather and temperature and humidity, which influences how forest fuels dry out.
“Most of the trends were explained by just those two,” Jane said. “It’s really a fact that we have both warming and drought.”
These trends are consistent with predictions made by climate models, which all indicate that the future will be hotter and drier, he said.
“It just confirms that climate change is increasing fire weather.”
Jain cautions that fires are affected by other factors as well, such as land use.
The study of extreme weather events, Jain said, focuses attention on the wildfires that cause the most damage. In Alberta, 97 percent of wildfire damage is caused by three percent of fires.
Jain said understanding where fire risks are greatest can help package officials plan for future fires.
“It is useful to know which areas are most affected by these increases in fire weather.”