Experts say forest fires are more frequent, and more intense, due to climate change

Leading Alberta scientists say climate change likely contributed to the Fort McMurray wildfire.

The fire has forced more than 80,000 people to flee and is already being described as one of the most devastating in Alberta’s history. Yet Marc-André Parisien, a research scientist with the Canadian Forest Service in Edmonton, says Alberta can expect even more intense fires in the coming years.

“We know from looking at weather records from the last 100 years that the fire season is lengthening, and intense fires like this are increasingly common,” says Parisien.

Parisien says last year’s drought (so extreme the Alberta government officially classified it as a disaster) and El Niño conditions, which caused much of Canada to experience a mild winter, made the vegetation and soil extremely dry—and therefore prime fuel for fire.

The Alberta government lists both droughts and forest fires as extreme weather events that are made more likely by climate change. The Natural Resources Canada website, last updated Feb. 2, features a similar warning about climate-change-fuelled forest fires.

Mike Flannigan, a professor at the University of Alberta and the director of the Western Partnership for Wildland Fire Science, is a leading expert on forest fires. “The area burned in Canada has increased over the past 40 to 50 years. This is due to human-caused climate change,” says Flannigan.

Flannigan says that rising temperatures in Canada lead to drying soil and vegetation, increased lightning strikes, and longer fire seasons. After the 2011 Slave Lake area wildfires, Alberta pushed the beginning of fire season from April 1 to March 1.

A 2014 study published in Science found that climate change led to an increase in lightning strikes—one of the common ways wildfires get started.

Stephen Johnston, chair of the earth and atmospheric sciences department at the University of Alberta, echoes Flannigan’s concerns. “Climate change makes extreme weather events more common. From that perspective, you could say this is more of the extreme types of weather that you’d expect.”

A 2013 study published in the Proceedings of the National Academy of Sciences showed that boreal forests—the type of forest currently burning in Fort McMurray—haven’t burned so frequently in at least 10,000 years.

In Canada, there’s also evidence that more forest is burning than ever before. A January 2016 study in Climatic Change co-authored by Flannigan, said that 8,000 fires burned over two million hectares on average per year, over the past decade. According to Flannigan, previous decades saw an average of about one million hectares burn per year.

While the experts agree, politicians do not. When Green Party Leader Elizabeth May said the Fort McMurray fire is likely a symptom of climate change, Prime Minister Justin Trudeau said linking any specific natural disasters to climate change is not helpful—and it’s better to map whether the frequency and intensity of disasters is increasing.

John Geddes interviews John Innes, UBC’s dean of forestry, on the impact of climate change: