Forest fires—truth going up in flames

Until the recent Canadian wildfires sent plumes of smoke over the densely populated cities around the Great Lakes and Eastern Seaboard, few people in those cities had ever experienced the weird orange haze of a forest fire or the temporary spike in fine particulates and pervasive smell of smoke. And understandably, many people reacted with some alarm. We city dwellers typically only see wildfires on television, usually alongside footage of fire crews and water bombers valiantly trying to put them out, which creates the impression they are somehow unnatural events that must be avoided at all costs. Of course, in reality, forest fires are not only natural but are essential to the life cycle of the forest ecosystem.

Unfortunately, politicians, reporters and climate activists rushed in to exploit this unusual event to push their agenda. They made a lot of glib claims about climate change causing wildfires to become more common. For instance, Prime Minister Trudeau tweeted “We’re seeing more and more of these fires because of climate change.”

That statement is false. Amid the smokescreen of untrue claims, nobody seems to have bothered looking up the numbers. Canadian forest fire data are available from the Wildland Fire Information System. Wildfires have been getting less frequent in Canada over the past 30 years (see chart below). The annual number of fires grew from 1959 to 1990, peaking in 1989 at just over 12,000 that year, and has been trending down since. From 2017 to 2021 (the most recent interval available), there were about 5,500 fires per year, half the average from 1987 to 1991.

The annual area burned also peaked 30 years ago. It grew from 1959 to 1990, peaking in 1989 at 7.6 million hectares before declining to the current average of 2.4 million hectares per year over 2017 to 2021. And 2020 marked the lowest point on record with only 760,000 hectares burned.

The record shows that the fraction of fires each year that become major (more than 200 hectares in size) peaked back in 1964 at 12.3 per cent. From 1959 to 1964, it averaged 8.7 per cent then dropped to 3.4 per cent in the early 1980s. As of the 2017 to 2021 interval, it had climbed again to 6.0 per cent, but that’s still well below the average 60 years ago (see chart below).

At the global level, satellite data from the European Space Agency also show that wildfire activity has been trending downward in recent decades and is currently approaching its lowest level since the record began in the early 1980s.

In an extensive discussion on the Royal Society blog back in 2020, U.K. forestry experts Stefan Doerr and Cristina Santin acknowledged that climate change may be making conditions for fire more favourable in some areas, but also noted it’s leading to reductions in other areas. As for the tendency for some fires to become larger and more dangerous, this can be traced to our approaches to forest management. “[Very] aggressive fire suppression policies over much of the 20th century have removed fire from ecosystems where it has been a fundamental part of the landscape rejuvenation cycle” they explained. This has led to a build-up of fuel in the form of woody debris leading to the risk of more explosive and unstoppable fires.

“We cannot completely remove fire from the landscape” they stressed. “That is the misconception that led to the ‘100% fire suppression’ policies in the US and elsewhere that have made things worse in many cases.”

As Environmental Studies professor Roger Pielke Jr. notes on his Substack, the UN Intergovernmental Panel on Climate Change is also reluctant to connect forest fire activity to climate change. While it notes there has been an increase in “fire weather” (hot dry conditions conducive to forest fires) in a few regions globally, it does not claim a “signal” of greenhouse gas influence is currently present in the probability of fire weather nor do they expect one to be detected over the coming century.

When it comes to climate change, we’re constantly told to “follow the science.” Yet the same people who say that also regularly fabricate claims about trends in forest fires here in Canada and globally, and the connection to climate change. Science tells us forest fires are not becoming more common and the average area burned peaked 30 years ago. It also tells us greenhouse gases won’t put out fires, and raising the carbon tax will only make it costlier to fight the ones now burning.