And no this is not simply an anomaly, the fire season is now longer and more intense than ever, courtesy of climate change
Taken in Osoyoos, British Columbia. Photo by Melanie Sandberg.
Even if you don’t live in North America, but have access to a smartphone, chances are that you have seen multiple images of red smokey skies across New York City that look like they are straight out of a Mad Max movie. For a brief period of time on Wednesday, June 7th, New York City was the city with the worst air quality in the whole world, with recorded pollution at about 3 times the national standard (PM2.5 air density recorded at 27.5 micrograms per cubic meter, when the U.S. Environmental Protection Agency’s (EPA) set national standard is 9-10 micrograms per cubic meter). This pollution is measured by the density of PM2.5 particles in the atmosphere, which refers to articles of dust and other matter that measure 2.5 micrometers and smaller in diameter. These particles happen to be small enough to be inhaled by human lungs and subsequently become entrenched. This is why PM2.5 particles are linked to a variety of health conditions and could even be fatal.
PM2.5 (Particulate Matter of less than 2.5 micrometers in diameter).
Source: U.S. EPA
According to Stanford scientists who were monitoring pollution via satellites, this was the worst wildfire smoke day in US history since 2006—and the smoke didn’t even originate in the United States. All of the smoke that covered New York City that day came from just due north in Quebec and Ontario, where wildfires continue to burn. But while New York has shifted out of focus, the situation in Canada has gotten worse, and the majority of the wildfires are now in the West of the country.
Active fires in Canada as of August 28, 2023 (Red = out of control; Blue = under control).
Source: CWIS.
According to the Canadian Wildfire Information System (CWIS), the fires in the country this year, as of August 23, 2023, have burned approximately 15.4 million hectares of land (or 154,074 km2) which is roughly 20% more area than the entirety of New Brunswick and Nova Scotia.
Additionally, the area that has burned so far is approximately 6 times the 10-year average of 2.5 million hectares to date (referring to from January to end of August). The country is at a national preparedness level 5, which indicates that there is a “full commitment to fighting these fires, demand for resources is extreme, and international resources are also being mobilized.” Tens of thousands of people have been displaced so far with the vast majority of displacement occurring in British Columbia (“BC”), where 35,000 people have been forced to evacuate so far and multiple sections of key transit routes have been shut down. The wildfires in BC have gotten so out of hand that the province was forced to declare a state of emergency as of August 18th.
The role of Climate Change
I’ve personally encountered numerous people that chalk up the situation in Canada to “business as usual.” While it is true that every year various forests in Canada go through a natural fire season due to the dryness of summer in those areas, the average total area that burns every year has been steadily increasing the past 20 years (See graph below).
Cumulative area (ha) burned yearly by Canadian wildfires. Using data from: Canadian Interagency Forest Fire Centre Inc. (CIFFC).
Climate variability and extreme climatic events, such as severe droughts, have long been linked to changes in fire regimes around the world. Whereas regions with grasslands, savannahs, or otherwise non-forested areas have seen a general decrease in total area burned (since the turn of the millennium), significant increases in area burned have been recorded in western and boreal North America. The main levers identified by the Intergovernmental Panel on Climate Change (IPCC) have been average temperature increases, and declines in precipitation during fire season (See Cross-Chapter Box 3 in Chapter 2 of the IPCC 6th Assessment Report). The increases in area burned also result in vegetative and soil changes, that in turn create other levers (such as reduced albedo and reduced evapotranspiration) for further intensification of the fire season in these regions.
The issue with the fact that most of the increases in area burned are within forested regions, is that these areas tend to produce higher emissions per area burned as there is a higher rate of fuel consumed per unit of area. So on the net, globally, the changes in fire regimes could result in higher greenhouse gas emissions.
The Associated Emissions in Canada
An important thing to note is that naturally occurring wildfires themselves are not necessarily a net contribution of carbon to the atmosphere. This is because there is almost an equivalent amount of carbon sequestration that occurs into regrowing vegetation, at different rates depending on the ecosystem. For boreal forests, and forests in general, this timeframe is 10 years—meaning that it takes 10 years for an equivalent amount of carbon to be sequestered by an area of forest as it is released through the burning of a certain area of forest. So in other words, if the total area burned yearly remains constant, there should be no net change in carbon released into the atmosphere over the long term.
However, as noted earlier in this article, the average area burned has been increasing every year in Canada. The difference between the cumulative total this year to-date and the 10-year average to-date is an area of 12,900,000 ha (129,000 km2). So how many additional emissions does this equate to? The rate of CO2e emissions from a boreal forest burn (using this as an average for Canada) is approximately 3.325 kg of CO2e per m2. This means that the additional 129,000 km2 to date this year represent roughly 429 Mt! of additional emissions.
To put this into perspective, Canada reported a grand total of 670 Mt of CO2e for the economy as a whole in the year 2021 (which does not include the emissions from wildfires). This means that this year’s fires to-date are set to increase the country’s emissions by about 64%.
To make matters worse, this doesn’t even include the lost carbon sink effect of the boreal forest. For the uninitiated, forests act as carbon sinks when they grow past a certain point, sequestering more carbon in soil, dead biomass, and new biomass than they release. The whole Canadian boreal forest was estimated to sequester approximately 28 Mt/yr from 1990 to 2008.
Predictions for the future
The current pattern is poised to continue into the future for North America with the wildfire season expected to lengthen and grow more intense (covering more and more area)—with the caveat that the IPCC scientists gathering evidence express this expectation with “medium confidence.” Forest fires create this unique climate feedback loop whereby more and more area is burned, releasing more and more emissions every year. These emissions then feed into the climate change effects the world is currently experiencing, which are themselves intensifying the fire season in boreal forest areas.
Interestingly enough, if we are able to take care of our environment properly, there is also a counterbalancing feedback loop. Intact old boreal forests sequester more carbon from the atmosphere than they release each year. Eventually these old forests fall into a balance as just the right amount of wildfires occur every year.
This anomaly in the Canadian wildfire season should be taken as a warning signal. We need to quickly act to protect our forests which are paramount in the fight against global climate change. If we continue allowing climate change to progress unchecked and we don’t adequately prepare, symptoms like wildfires in boreal forest areas may soon get out of our sphere of control and influence. More extensive wildfire management practices, such as fuel-reduction treatments, should be rolled out nation-wide in response to this year so that we can keep this climate change symptom in check. At the same time, if we protect the country's vast forest resources, they may in turn also help us ward off some of the other extreme effects of climate change.
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