The Decibel - Canada’s wildfires dwarf emissions from all other industries

Episode Date: September 7, 2023

This year’s wildfire season has broken all kinds of records – including on emissions. Canada’s wildfires have doubled previous records for greenhouse gas emissions – and they’ve caused more emissions than all of Canada’s industries combined.Dr. Werner Kurz, a senior research scientist with the Canadian Forest Service, explains how these wildfires are changing Canada’s forests, what it means for Canada’s emissions and how we can lessen the damage from wildfire seasons in the future.Questions? Comments? Ideas? Email us at [e-mail]

Canada's wildfires have been breaking records this year. More land has been burned in 2023 than in several previous years combined. Thick, hazy smoke covered communities across the country for weeks at a time. And the fires are emitting tons of carbon, more than double the previous record. It is absolutely unprecedented what we're seeing. emitting tons of carbon, more than double the previous record. It is absolutely unprecedented what we're seeing. And as a scientist who has been working on this for more than 30 years, there is no satisfaction in saying, we told you so.

But it is really a big surprise to the scientific community just how rapidly the things that we have been predicting are unfolding in Canada now with regard to increases in area annually burned. Dr. Werner Kurtz has been studying forests and their carbon stores for 30 years. He has a PhD in forest ecology and is a senior research scientist with the Canadian Forest Service, which is part of Natural Resources Canada. He's also a principal investigator with the Pacific Institute for Climate Solutions Wildfire and Carbon Project. Today, Werner tells us how these wildfires are changing forests in Canada, what it means for Canada's emissions, and how we can lessen the damage from wildfire seasons to come. I'm Mainika Raman-Wilms, and this is The Decibel, from the Globe and Mail.

Werner, thank you so much for being here today. Yeah, you're welcome, and I appreciate your interest in this important topic. So this has been a record-breaking year for wildfires, including when we look at the emissions from those wildfires. What have we seen so far this year in emissions from wildfires? We have indeed seen unprecedented numbers. For the managed forest, we are estimating about 6 million hectares that have burned. And as of August 30th, and the emissions associated with that, and these are rough preliminary estimates, are about 850 million tonnes of carbon dioxide equivalent. And to put that in perspective, the emissions from all of the

sectors in Canadian economy are about 670 million tonnes of CO2. So the wildfires this year have already emitted more carbon than the entire Canadian economy, and many fires are still burning. I mean, this is an astounding number here. Like, we're talking so more than the emissions from oil and gas. And when we produce oil and gas, right, cars, all that transportation, the wildfire emissions are more than all of that combined. Correct. Wow. Yeah, in this year. So how do we know what the emissions are from wildfires? I mean, how are researchers actually calculating this? Yeah, that's an excellent question. So what we need to understand, first of all, is that the carbon that is in wood

and 50% of the weight of wood is carbon that was taken from the atmosphere. So the carbon dioxide is removed through photosynthesis, the oxygen is released back into the atmosphere, and the carbon is stored in trees. So wood is essentially a huge amount of carbon and a huge amount of stored energy, as anybody knows that ever sat around a campfire in Canada. And so what's happening in fires in general is that all that stored energy is released again. The carbon is re-oxidized. So we take the carbon out of the wood and turn it back into CO2. That's a process that releases a lot of energy. And the CO2 is the greenhouse gas that is then being added back into the atmosphere. The problem is that the uptake goes very slowly. We all know that it takes a long time for a tree

to grow in Canada, but the release happens very rapidly. In other words, the carbon that has been stored over decades, in some cases centuries, in trees and also in the forest floor can be released rapidly back into the atmosphere in a matter of a few hours. And do the kind of emissions, I guess, change depending on how the fire is burning? Yeah, that's also a really good question. So if we have an intense fire that releases a lot of heat, we mostly release carbon dioxide and some carbon monoxide. But as we go to a smoldering phase of burning, so we have basically incomplete combustion, not enough oxygen is available. And that incomplete combustion then releases methane, another potent greenhouse gas, 25, 28 times as potent as carbon dioxide.

So even small emissions of carbon as methane have huge impacts on future global warming. So when scientists talk about emissions, we usually use the units of megatons of carbon dioxide equivalent. That's the same as millions of tons of carbon dioxide equivalent, that's the same as millions of tons of carbon dioxide equivalent. And carbon dioxide equivalent is basically taking the different greenhouse gases, such as carbon dioxide, methane, and N2O, and converting them from their impact on warming into a common currency, and that is called carbon dioxide equivalent. And it's done by multiplying each of the gases by a global warming potential factor that quantifies the climate forcing that each gas has on the atmosphere and the climate system.

Okay. So earlier, Werner, you talked about, you used the term managed forests. So what is a managed forest and how does that factor into the calculations we're doing? Yeah. In the context of the conversation that we're having, we use the term managed forest to follow the guidelines of the Intergovernmental Panel on Climate Change for greenhouse gas reporting, where countries are basically asked to report an anthropogenic, so human-caused emissions and removals. So managed would imply a range of activities that influence the greenhouse gas balance. So even park management. So we have reserved areas and parks that are deemed managed for the purpose of greenhouse gas inventory reporting. Managed does not mean just timber production. It means any values that are of importance to humans. So conservation, riparian zones are still deemed managed forests because fire suppression is one of the activities that is affecting most of those areas.

So if we take emissions from the managed forests and the unmanaged forests in Canada, do we have an estimate for the total emissions from all wildfires in Canada this year? As of August 30th, the area burned is about just over 15 million hectares. And the preliminary estimate of the total greenhouse gas emissions is 2000 megatons of CO2 equivalent. And so I want to emphasize that these are preliminary numbers. So the uncertainty is high. So that could well be plus minus 200 million tons or something like that. But the point is, the magnitude of these emissions has now reached about three times the emissions from all other sectors of the Canadian economy combined. bending numbers. And so this matters to society and to humanity, because what we are now seeing is that climate change impacts are accelerating future climate change. We call it the warming is feeding the warming, you know, scientifically, it's a positive feedback loop. So as the world

gets warmer, we create more conditions that are conducive to more forest fires. And these forest fires are adding more greenhouse gases to the atmosphere, which then will further accelerate the warming. And this is only one of the early ecological feedback loops. The other elephant in the room here is that science is also predicting that with warming, we will see more permafrost thawing. And Canada has huge areas of permafrost, as does Russia and many other circumboreal countries. And when these processes are being unleashed, they will be much slower than fire releases, but the quantities of carbon that can be released over time are much larger. So that's the same warming is going to

feed the warming is feeding the warming. And so this is this is alarming to society because we begin to lose grip of our ability to control the future climate. When it was just a question of fossil fuel emissions, we could just dial back on our fossil fuel emissions and live happily ever after. Having said that, now that we have emitted as much fossil fuel into the atmosphere and we see these climate warming processes unleashing their impact on ecosystems, now we have processes that are adding carbon dioxide to the atmosphere that will be much more difficult to control. I know of no mechanism by which we could limit permafrost thawing impacts and the associated releases of CO2 and methane at this time. Yeah, because if

these are emissions that are coming from non-human activities, these are not emissions that we can control then in a way. Because if we know the emissions are coming from our cars, if we stop driving as much as a very simple example, right, we're reducing emissions. Absolutely. We can't control fees in that way. Yep, exactly. We'll be back in a minute. So we've just been talking about how significant these emissions are from wildfires, but I understand that these emissions from wildfires aren't actually included in Canada's tallies of greenhouse gas emissions, which seems

strange to me. Why is that? In the managed forest, we say that the wildfires are beyond human control and often not caused by humans. The vast majority of area burnt in Canada is due to lightning strikes. And so therefore, what we do is we estimate and calculate and present in the Greenhouse Gas Inventory Report and in the State of Forest Report the emissions both from human activities and from wildfires. But we do not take the wildfire emissions when we measure progress towards emission reduction targets. So that is limited to changes in forest management, wood use, etc. Yeah. Yeah. So I guess, is that going to be changing over time? Like we're going to be counting this, I would imagine, if this continues to be so significant? Well, this is a really important question. And the question that we need to ask

ourselves is, are the emissions from climate change-induced wildfires or, in the future, permafrost thawing, are those emissions Canada's responsibility alone? Or are they part of a global impact of climate change? And so the scientific community is arguing that we need to stick to the process that we're currently using, which is anthropogenic emissions and removals. But the Paris Agreement has developed a second mechanism. It's called the global stock take, where the scientific community basically looks at, okay, the sum of the greenhouse gas inventories from all the countries report one number. But what the atmosphere experiences is a different number because of all the things that are not included. So ocean feedbacks, feedbacks from permafrost thawing, wildfires, etc. And so the global stock take is really measuring how much,

what is the impact on the atmosphere? And do we need to increase our efforts in other sectors to reduce emissions and get us back on the target where we want to be with emission reductions. I want to talk about just the forest and the ecology for a moment here, Werner. Given how much damage is happening to the forests when these wildfires are happening, I mean, what are the consequences of that? Yeah, first of all, let's remember that most of Canada's forests are fire adapted ecosystems. In other words, they have always been subjected to wildfires. They have burned in some cases every few years with light underburns, in some cases less frequently, but more severe burns. But in general, forest ecosystems are capable of regenerating after fires and have done so for centuries and millennia. What is new now

is the intensity of the fires and the area burned. And that has ramifications for what's left behind. So these very intense fires in particular, or in areas where we have two fires in rapid succession, so you have one fire, causes a lot of damage, kills a lot of cheat, these start falling down. 10 years later, you have a second fire when you already have thin forest floor, et cetera. And now we have many cases where all of the forest floor is burned all the way down to the mineral soil. So now we have completely different conditions for regeneration, forest regrowth, et cetera. And what science is predicting is that we will see increasing examples of forest ecosystems transitioning to non-forest. In other words, if you have very intense fires and regeneration of trees fails, you may get grasslands. And you can see that in the Okanagan, for example, or other parts of British Columbia, where you're already at the margin of survivability of trees. The trees

are on the north and east side of slopes. On the south and west side, where it's hotter and drier, you have grasslands. And you just have to fly over and you see that. So grasslands are predicted to expand in some areas. So this could really then change kind of the makeup of the natural land here then? It will. It will. This is not a can. It will. That is not all bad. Of course, it has adverse impacts for timber production, et cetera. But these non-forest ecosystems may in fact help provide fire breaks

in the future to help reduce these megafire events that we have seen recently. Okay, interesting. When you're talking about the change in the makeup of the land, though, this is a pretty significant thing. And I'm used to always hearing, I guess, about how Canada's forests are a huge carbon sink, right? They're supposed to help us with this, that they actually help reduce our emissions. Is that still the case?

Well, not now. It was the case in the 1990s. Throughout the 1990s, these forests have been taking up significant amounts of carbon every year. Even with harvest and accounting for all the emissions of harvested wood products, the whole forest sector was still a carbon sink. What has been happening recently, starting in the 2000s, is that climate change impacts are starting to contribute to insect outbreaks. So the big mountain pine beetle outbreak that we saw in Western North America and other insects that are expanding in range and impact are undermining the sink strength of the forests. And then in the last decade, the combination of insects and now these big

increases in forest fires have resulted in the forest really transitioning to carbon sources. I mean, that's a pretty big deal. So Canada's forests are now releasing more carbon than they're taking in. Yes. And why this matters is from a global perspective. Historically, over the last 50, 60 years, of all the fossil fuels that humanity has been emitting, half roughly ends up in forests and oceans in about equal parts. So 25%-ish goes to forests, globally 25% to oceans. That means that the impacts of our fossil fuel emissions are cut in half because only half of

it remains in the atmosphere. The other is taken up by oceans and forests. So as we go forward and forests are increasingly unable to contribute the uptake of this carbon and worse are adding their own carbon to the atmosphere, the rate of climate change will further accelerate. I mean, honestly, this sounds pretty dire. Like if Canada's forests are no longer a carbon sink, and we've got so many emissions coming from things like wildfires, is it too late to change what's going on? It is serious. But I think one of the things that we need to think about are what can we do? What are some of the solutions? So one of the questions that we as a society need to ask is, to what extent do we need to change forest management

to focus not on timber production, not on just conservation and storing carbon in forests, but actually using the forest as a mechanism to remove carbon dioxide from the atmosphere. Younger forests that are actively growing are removing more CO2 from the atmosphere. So it's the photosynthesis, the ability to extract carbon dioxide from the atmosphere and turn it into wood and biomass. If we can manage our forests, say in Western North America, through thinning and prescribed burning and other activities, so that we have and maintain more open forests that are actively removing carbon dioxide from the atmosphere, but are at less risk from wildfire. Then we have achieved a nice outcome because now we maintain a forest. It's different than the

forest that we have today. It's maybe less dense and has larger trees in it. And we see examples of that from old photos, but it's at lower risk from fire. So that means we maintain a carbon sink and we maintain carbon stores. That doesn't work in all ecosystems. These are, you know, any prescription and mitigation option that one proposes has to be put into the context of the ecology and the fire risk, etc. So can we get into some of the solutions? And like, what are some of the solutions that people are trying that might actually show some promise here? Yeah. So we have to understand, and let's focus on Western North America right now, because that's where a lot of this research has been happening. And that's where a lot of the

fires have been happening. We have to understand that how we got here is really a century of fire suppression. We have historically had cultural burning and natural burning that created a certain landscape condition that has been altered over the last hundred years by suppressing wildfires. As a consequence, we have had ingrowth of trees. We used to have forests that had large trees with canopies high up in the air that are now invaded by seedlings and smaller trees that historically would have been taken out every 10 years by a ground fire, but now they grow bigger and bigger. And now we have what is called ladder fuel. So you have contiguous foliage or canopy from the ground all the way into the canopy of the big trees. If this is now hit by a grass fire or ground fire,

the flames will be carried all the way up into the canopy and the whole forest will burn. So by having excluded small fires for a long period of time, we've completely changed the ecosystem and created huge amounts of carbon entries in these forests. So in terms of solutions, what we need to do are looking at three things. We need to reduce the fuel load that has been the consequence of fire suppression. In other words, we need to have less biomass and stored energy in the landscape. And that can be done through thinning, it can be done through removal of understory, it can be done through reintroduction of cultural burning, prescribed fires. There's a whole suite of tools in our toolbox aimed at reducing the fuel

load. The second thing we can do is reduce the flammability. So if you consider an aspen stand or alder or birch with foliage in the summer, the foliage is green and damp, it's a completely different environment than a coniferous forest where needles burn very quickly. So coniferous forests, needle leaf trees are much more flammable than some of the broadleaf trees. And because the needle leaf trees are more valued by the timber industry, we have actually actively suppressed the re-emergence of broadleaf species. And now we recognize, hey, if we had more of that in the landscape, it would help us suppress fires. Oh, so we actually changed the makeup of the forest to support these lumber activities. Exactly. Yeah. So that's the second factor. And

the third factor is then the overall landscape design. We cannot just work on tinkering here or there. We need to look at large areas around communities and begin to ask ourselves the question of in areas of high fire risk, can we redesign the landscape? Can we create more open spaces? Can we have more thin coniferous forests? Can we have more broadleaf forest? Can we have grasslands or no forests in some areas? There are things that we can do that combined will alter the ability of fires to spread and to burn at high intensity. Verner, this was a very eye-opening conversation. Thank you so much for taking the time. Thank you for the interest in the subject. That's it for today.

I'm Mainika Raman-Wells. Our producers are Madeline White, Cheryl Sutherland, and Rachel Levy-McLaughlin. David Crosby edits the show. Adrian Chung is our senior producer, and Angela Pachenza is our executive editor. Thanks so much for listening, and I'll talk to you tomorrow.