Guest Host: Sabri Ben-Achour

Flames rise off Highway 63 on May 7 outside Fort McMurray, where raging forest fires forced more than 88,000 from their homes.

Flames rise off Highway 63 on May 7 outside Fort McMurray, where raging forest fires forced more than 88,000 from their homes.

Since the beginning of May, a massive, out-of-control fire has been raging in boreal forest lands in Alberta, Canada. The fire forced the evacuation of more than 80,000 residents of Fort McMurray and halted oil sands production. Scientists say climate change has contributed to the growing number and severity of wildfires in the world’s boreal forests. Hot, dry weather has lengthened fire seasons and created ideal conditions for wildfires. The fires in turn increase emissions of greenhouse gases. For this month’s Environmental Outlook, we talk about wildfires, climate change and threats to North America’s forests.


  • James Hubbard Deputy chief for state and private forestry, the U.S. Forest Service
  • Mike Flannigan Professor of wildland fire, University of Alberta, Department of Renewable Resources; director, the Western Partnership for Wildland Fire Science
  • Tatiana Loboda Associate professor, the Department of Geographical Sciences, the University of Maryland, and a principal investigator on NASA's Arctic-Boreal Vulnerability Experiment


  • 11:00:02

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  • 11:06:54

    MR. SABRI BEN-ACHOURThanks for joining us. I'm Sabri Ben-Achour from "Marketplace" sitting in for Diane Rehm. She's on a station visit to WFAE in Charlotte, North Carolina. The world's boreal forests are under increasing pressure from resource exploration, development and, thanks to warmer, drier weather, wildfires. A huge wildfire in Alberta, Canada, has been burning for nearly a month, consuming an area almost twice the size of Rhode Island.

  • 11:07:20

    MR. SABRI BEN-ACHOURAs part of our ongoing environmental outlook series, we discuss forest fires and the role of climate change. And joining me in the studio, James Hubbard of the US Forest Service and Tatiana Loboda of the University of Maryland. And from a studio in Edmonton, Canada, Mike Flannigan of the University of Alberta and the Western Partnership For Wildland Fire Science.

  • 11:07:42

    MR. SABRI BEN-ACHOURThank you all for joining us.

  • 11:07:45

    MS. TATIANA LOBODAMy pleasure.

  • 11:07:45

    MR. JAMES HUBBARDGlad to be here.

  • 11:07:46

    BEN-ACHOURAnd we'll be taking your comments, questions throughout the hour. You can call us on 1-800-433-8850. You can send us your email to You can also join us on Facebook or Twitter. Mike, you've -- I've seen videos of this fire. 1.2 million acres burned. It is like something out of a science fiction movie. It's 375 miles long. Take us back to May 1 when it started and explain how it spread so fast.

  • 11:08:22

    MR. MIKE FLANNIGANWell, first, you know, the fire start was under investigation, but now we know that it was a human-caused fire. We don't have all the details yet, but this is expected because it was so close to town and because in early May, we don't get much lightning in this part of the world. So it was very likely a human-caused fire. But what was so unusual is that we had a very dry, mild winter followed by a hot spring and dry, record-breaking heat with temperatures in the 90s Fahrenheit, which is record-breaking for this part of the world this time of the year.

  • 11:09:03

    BEN-ACHOURIn Canada.

  • 11:09:03

    FLANNIGANAnd so the fields were dry and then we had hot, windy conditions. We had the ignition so everything was lined up and away it went.

  • 11:09:12

    BEN-ACHOURAnd did it start in the woods? Did it start on the edge of town? Do we know?

  • 11:09:19

    FLANNIGANWell, we know approximately where it started. It started just outside of town, a couple kilometers, just over a mile, and it was in a hydro corridor or utility line, a power line corridor and so it could've been a quad, a four-wheeled vehicle, ATV, whatever you want to call them, sparks from that. I haven't seen the investigators report yet, but that's a likely cause of a spring fire. Sometimes power lines cause fires if a tree blows against the power line and sparks start.

  • 11:09:54

    FLANNIGANSo but you're listeners need to understand that there are three ingredients for forest fires and all three were present for this fire. First is the fuels, the stuff that burns, the dead organic material on the forest floor, needles, leaves, the shrubs, the trees, conifers in particular are very flammable. Then, you need ignition, lightning and people are the two causes for fires. In this case, it looks like a human cause.

  • 11:10:17

    FLANNIGANAnd the third is the weather, hot, dry, windy weather. We had all three and the stage was set.

  • 11:10:24

    BEN-ACHOURPerfect combo. Tatiana Loboda, can you tell us what a boreal forest is and how its characteristics affect the way that it burns?

  • 11:10:34

    LOBODAWell, boreal forests, by definition, is the northern forest, right? Forest in the high northern latitudes. It can look very different and in different parts of the world, it does look different, usually, very frequently, it's a coniferous forest. It can be a spruce forest or a large forest or a pine forest. And sometimes it's mixed forest when you have deciduous species like aspen and birch mixed in with coniferous species. So what makes it so flammable is part of the reason is that coniferous species burn.

  • 11:11:13

    LOBODAThey have lower levels of live fuel moisture than deciduous species and in addition to that, we have a lot of forest litter and deep organic layer in many of the boreal forests. That's the organic material that falls on the forest floor, but because it's so cold there most of the year, right, it doesn't decompose.

  • 11:11:36

    BEN-ACHOURIt doesn’t decompose.

  • 11:11:37

    LOBODASo it remains there and creates this deep organic layers that store carbon very efficiently.

  • 11:11:43

    BEN-ACHOURRight. It stores -- it does store a ton of the earth's carbon, doesn't it?

  • 11:11:47

    LOBODAIt does. It does. And, in fact, boreal forests store more carbon than the tropical forests and most of it is in this soil organic layer.

  • 11:11:59

    BEN-ACHOUREven more than, like, the Amazon?

  • 11:12:00


  • 11:12:00

    BEN-ACHOURWow. Mike, what kinds of creatures -- we always think of forests as just the trees, but what kind of creatures live in there?

  • 11:12:08

    FLANNIGANThere's a variety of flora and fauna in the boreal forest. There's ungulates like caribou, bears, wolverines, porcupines, reindeer. It goes -- lots of bird species, squirrels, chipmunks. It goes on and on and on.

  • 11:12:29

    BEN-ACHOURAnd these forests do ring the sort of top of the northern hemispheres, right?

  • 11:12:36

    LOBODAYes, they do.

  • 11:12:36

    BEN-ACHOURThey're not just in Canada, right?

  • 11:12:38

    LOBODANo. They're all across -- circumpolar boreal, big, big portion of those is in Russia, in fact, and across northern Eurasia as a whole.

  • 11:12:48

    BEN-ACHOURJim Hubbard with the US Forest Service, what causes most wildfires.

  • 11:12:55

    HUBBARDOh, it's a combination of what Mike mentioned. It's lightning and it's human-caused. And most of the human-caused is accidental. There is some arson in places, but most of it's accidental human and then we have our biggest problems in the western United States with dry lightning storms. And we'll get a dry lightning storm where the frontal passage that might start 2,000 fires and it's hard to keep up with that many.

  • 11:13:26

    BEN-ACHOURWow. What's the proportion of human-caused versus natural causes? Is it like 50/50?

  • 11:13:32

    HUBBARDYeah, close.

  • 11:13:34

    BEN-ACHOURAnd Mike, do we know how the Fort McMurray fire started exactly? Just that it was human-caused, I guess.

  • 11:13:44

    FLANNIGANNow, we know it's human-caused. It's interesting, though, that, you know, in the western United States, 1 percent of the fires are responsible for 99 percent of the area burned. In Canada, 3 percent of the fires are responsible for 97 percent of the area burned.

  • 11:14:00

    BEN-ACHOUROh, wow.

  • 11:14:00

    FLANNIGANSo what happens is just a few -- relatively, a few fires cause all the impact and they typically occur on a relatively few days of very severe fire weather.

  • 11:14:13

    BEN-ACHOURSo that's an interesting point. It's not just -- so it's not just the number of fires caused by humans versus nature, it's that the human caused fires are much, much worse, is what you're saying.

  • 11:14:25

    FLANNIGANNo. Some of those fires that get away are human-caused, some are lighting caused.

  • 11:14:29


  • 11:14:30

    FLANNIGANSo it's not a cause. It's just the fact that some fires escape. Fire management agencies are very efficient at what they do. They put out 90-some percent of the fires, 95, 97, depending on what jurisdiction you're looking at, 99. But the ones that escape are the ones that are problems. Sometimes it's human-caused. Sometimes they're lightning caused. Most of the human-caused are put out right away because they're detected quickly and then action quickly.

  • 11:15:00

    FLANNIGANThe whole strategy for fire management for unwanted fires, and we can talk about the other side later, but unwanted fires is you hit it hard. You hit it fast. If the fire's the size of my office, which isn't all that large, it's easy for an experienced crew to put that out. If the fire's the size of a football field and it's hot, dry and windy and there's lots of dry fuel, we have a problem.

  • 11:15:21

    BEN-ACHOURYeah. How many fire fighters are on the massive Fort McMurray fire? What's it going to take to put that one out?

  • 11:15:28

    FLANNIGANWell, so if we go back to the three ingredients, it's really up to the fuel and weather when it's -- when the fire's intense, you can't put boots on the ground. You can't put firefighters in front of the flames because it's too dangerous so instead of working the head of the fire where it's intense and, you know, your listeners may have seen the video, those intense flames engulfing the whole crown of the trees. We call those crown fires.

  • 11:15:53

    FLANNIGANAnd the rain of burning embers, it's not safe to put people in front of that fire. And so you work the sides of the fire, called the flanks, or the back. And you build a fire line or a fire guard with bulldozers, caterpillars or with boots on the ground. Now, at the head of the fire, we can use aerial attack, retardant, foam, water, but when the fire gets so intense, and most of our crown fires in North American boreal forests are -- these are crown fires, and even aerial attack has become less effective, perhaps ineffective when it's so intense.

  • 11:16:28

    FLANNIGANThis fire was developed its own thunderstorm, what we call a pyro cumulonimbus. And interesting...

  • 11:16:34

    BEN-ACHOURRecreated its own weather.

  • 11:16:36

    FLANNIGANAnd also, there was lightning observed from this pyro cumulonimbus.

  • 11:16:40


  • 11:16:41

    FLANNIGANAnd we've seen that before, but what I have not seen before is that some of these lightning strikes start new forest fires so it's self-perpetuating, self-regenerating. It was quite interesting.

  • 11:16:51

    BEN-ACHOURSo how are we gonna put it out? What do we need?

  • 11:16:56

    FLANNIGANOkay. So getting back to the three ingredients, fuel and weather.

  • 11:17:03

    BEN-ACHOURSo rain.

  • 11:17:04

    FLANNIGANYou wait for rain and I'm talking about two inches of rain to put something out because as Tatiana was saying, it's burning the deep organic material, what we call peat. Anything over 40 centimeters in depth or more we call peat. And so the fire starts on the surface, and if conditions are right, can spread to the crown so you get this high intensity fire, but also can burn underground in the peat and it can smolder there for weeks, months and even through the winter and start up again next spring.

  • 11:17:32

    FLANNIGANSo you have to wait for cooperative weather or the fuel runs out, but there's tons of fuel in the boreal so we -- it'll keep burning until the weather changes or there's a quiet period that allows them to work the head of the fire with bulldozers and aerial attack.

  • 11:17:46

    BEN-ACHOURAll right. Well, coming up, more of our conversation on the threatened boreal forests.

  • 11:20:02

    BEN-ACHOURWelcome back. I'm Sabri Ben-Achour with "Marketplace" sitting in for Diane Rehm. With me is James Hubbard, he's deputy chief for state and private forestry at the U.S. Forest Service, Tatiana Loboda, associate professor at the University of Maryland and an investigator on NASA's Arctic-Boreal, oh, my gosh, Vulnerability Experiment. And Mike Flannigan in a CBC Edmunton studio, he's a professor of wildland fire science at the University of Alberta.

  • 11:20:30

    BEN-ACHOURJames, can you -- you say that firefighters are seeing things that they haven't seen before.

  • 11:20:41

    HUBBARDThey are. And we hear this after every season, the kind of fire behavior that's resulting from the changed condition. And so our most experienced firefighters are coming back and telling us -- we've seen a lot of fire, we've been doing this for 30 years...

  • 11:20:59


  • 11:21:00

    HUBBARD...and we've never seen that before. So that changed behavior is a result of the dry fuels. It's a result of the changed climate in terms of lower humidities and higher temperatures and the long-term drought. And so the weather patterns have something to do with it. But that condition of the forest is -- has changed. And we complicate that with homes, with what we call the wild and urban interface. And we have 44 million homes in the United States that are up against the forest or mixed in with the forest. And when fires start there, that's our priority. So as we talked about before, if we get multiple starts -- a thousand starts from a lightning storm -- our priority is going to be to protect the property values, the homes, the people.

  • 11:21:55


  • 11:21:56

    HUBBARDAnd as we do, then the fires that we don't get to, the 1 or 2 percent that Mike mentioned, they get big and we have to deal with them later.

  • 11:22:07

    BEN-ACHOURAnd I understand the actual seasons -- it's not just the fires but it's the wildfire seasons are changing in North America.

  • 11:22:16

    HUBBARDWe've seen cycles before but currently we, if you compare now to 30, 40 years ago, our season is about 80 days longer than it was.

  • 11:22:27

    BEN-ACHOURIt starts earlier, finishes later.

  • 11:22:29


  • 11:22:30

    BEN-ACHOURI actually -- I read -- it might have actually been in one of your papers, Tatiana, that the fires in Alaska last year were the worst in 10,000 years, worst on record.

  • 11:22:48

    LOBODAThey weren't actually the worst. It depends on how you define the worst.

  • 11:22:52


  • 11:22:53

    LOBODAIn fact, 2004, I believe, was the biggest fire on record in Alaska, with over 6-million acres burned. 2015 was the second largest. And then 2005 was the third largest. So we've had three largest fires in the record in the last 15 years. Right?

  • 11:23:13

    BEN-ACHOURSo when -- what about in Russia? Are the boreal forests there also seeing more and worse fires?

  • 11:23:19

    LOBODADefinitely. In fact, in our most recent studies, when we compared the disturbances in the 15 years -- preceding year 2000 and the 12 years after that, we have noticed a much greater increase in forest loss in Siberia and the Russian Far East, specifically.

  • 11:23:42

    BEN-ACHOURSo this plus the longer fire reasons -- I mean, is this about climate change? Is this about increasing temperatures? What role does temperature play?

  • 11:23:52

    HUBBARDA big role and in a lot of different ways. It affects the behavior of the fire when we're in season. It has to do with the dryness of the fuels, the fuel moisture that we have to contend with. And the dryer that is, the more likely we are to get an ignition and the faster spread from that ignition. So temperature controls it a lot. Humidity controls it quite a bit too. Surprisingly it doesn't take a lot of change in humidity and you've got a different kind of forest condition and therefore fire behavior.

  • 11:24:27

    BEN-ACHOURWe have a tweet from Mike. And he says, the problem is that we don't let these fires burn. We need burns so fires like the one in Canada don't get so out of control. Is it just that?

  • 11:24:39

    HUBBARDIt's not just that but that is a valid point. We definitely need more fire on the land. The question is, how do we manage that fire? When do we manage that fire? Do we do it under a prescribed condition or do we do it with the unplanned wildfires that we normally suppress. But how much fire we have on the land affect the condition, it affects the mosaic of the forest on the land, it gives firefighters a better chance at their suppression tactics.

  • 11:25:12

    LOBODAIf I can follow up on that.

  • 11:25:14


  • 11:25:14

    LOBODAIt's not as that cut and dry. Because, in Alaska, most of the fires are not controlled. They are let-burn fires.

  • 11:25:23

    BEN-ACHOURLed burned?

  • 11:25:24


  • 11:25:25

    BEN-ACHOUROh, let-burned.

  • 11:25:25

    LOBODASo this is the policy. The fires starts, there are no homes to protect, let it burn.

  • 11:25:30


  • 11:25:30

    LOBODARight? And what we see is much larger, much more severe fires in the last 15 years.

  • 11:25:38

    BEN-ACHOURMike. Mike, go ahead.

  • 11:25:42

    FLANNIGANSo, you know, James is correct in that, you know, the wildland-urban interface, we're seeing more and more. Now, more than ever, people are working, living and playing in the boreal forest. You know, the oil sand developments are very close. The bitumen extraction, you know, there's thousands of workers in camps outside of town, so there's more exposure. So fire is part of the natural environment of the boreal. And people are, you know, becoming part of the boreal. So you get this intersection between people and fire, sometimes with devastating results like we've seen recently in Fort McMurray.

  • 11:26:21

    FLANNIGANNow, you say, well what can we do about it? Well that -- we go back to the three ingredients. We can't do anything about the weather. We can't do anything about lightning. We can do things about human-caused fires. And fire management agencies are pretty good at prevention, education, fire bans, fire restrictions, forest closures. These are all tools that they use fairly effectively. But that leaves fuel. And we can do something about the fuel, not for the -- across the whole boreal forest, which is vast, but around values, like communities, we can treat fuels.

  • 11:26:53

    FLANNIGANIn the United States has a program called Firewise. In Canada, we call it FireSmart, same principle though. There's guidelines for homeowners and communities to help better protect themselves against fire.

  • 11:27:06

    BEN-ACHOURIs -- speaking of weather, has the -- has El Nino played a big role in the Fort McMurray fire or in other fires in the boreal forest, Canada, Alaska?

  • 11:27:17

    FLANNIGANWell, I'll tackle this to start and then -- but I'll get back to temperature for a second, okay?

  • 11:27:25


  • 11:27:25

    FLANNIGANSo temperature and climate change, numerous studies have found temperature important for fire on the landscape, so an area the size of Alaska, for instance. Not an individual fire where wind and fuel become critical, but over a large area over a period of time, like a month or a fire season. Longer fire seasons we've already talked about. In Alberta, our fire season starts officially March 1. It used to be April 1. It's a month earlier. And studies have shown that our fire seasons are starting earlier. Second, the warmer it is, the more lightning we get. A recent study in the United States found for every degree of warming, you get a 12 percent increase in lightning. More lightning, more fire.

  • 11:28:03

    FLANNIGANAnd the third reason -- it's probably the most important -- is that the warmer it gets, the more efficient the atmosphere becomes at sucking the moisture out of the fuel. So you get dryer fuels. Dryer fuels, easier for fires to start and spread. Now there's a caveat there, in that, if we get increased precipitation, it can compensate for the drying effect from increasing temperatures. But most of the models of future fire weather suggest we're not going to see that increase in precipitation so it is going to be drier. So we have a real problem with warming temperatures.

  • 11:28:38

    LOBODALet me...

  • 11:28:39


  • 11:28:39

    LOBODA...make a comment on the precipitation thing.

  • 11:28:41


  • 11:28:42

    LOBODASo many models are predicting that precipitation is either going to moderately increase or stay the same. But what has been observed, at least in Russia, is that the precipitation regime is changing. Instead of having smaller rain events distributed throughout the year, you may have very strong, concentrated rain events in the beginning or in the middle of a year. But that leaves a very large period when there is no rain whatsoever and that gives the opportunity for the fuels to dry out. So that change in the regime without the changing in the amount of precipitation can actually increase fire danger conditions.

  • 11:29:25

    BEN-ACHOURYeah. And I've also read that climate change also changes the nature of the forest. You get more larch trees that are -- contribute. Can you explain that, how the climate change actually affects the composition of the forest, which in turn affects the fires?

  • 11:29:43

    LOBODAThere are several scales that we -- that change in time, happens, right? So at the immediate scale, the forest floor, the grasses, the small shrubs under short term of a warming of the climate can become very robust. They can -- there can be a lot of them. And that's what helps to carry fire through the forest floor, right?

  • 11:30:09


  • 11:30:10

    LOBODAAnd the taller the shrubs get, the easier it becomes for the fire to jump from the ground into the crown. We call those ladder fuels. They climb those ladders and turn into crown fires. Over longer time periods, you can see a complete change in forest composition, where more drier climate species outcompete the species that were there previously. And you have, you know, pine forests replace the large forest, for example, and bringing with it different fire regimes again.

  • 11:30:47

    HUBBARDSo the climate change has affected the composition of the forest. That's for sure.

  • 11:30:51

    BEN-ACHOURHmm. Hmm.

  • 11:30:52

    HUBBARDAnd it's done so in a way that makes it more fire prone.

  • 11:30:57

    BEN-ACHOURAnd Tatiana or Mike, can you explain how the wildfires, in turn, contribute to an increase in greenhouse gasses?

  • 11:31:09

    BEN-ACHOURGo ahead, Tatiana.

  • 11:31:09

    LOBODAAll right. Thank you. So the relationship there is very straightforward, right? The trees, the organic soil layer, it contains carbon, right? And it immediately releases, when the fuel is being consumed, the carbon is released in the atmosphere. It's not only the carbon, which is a very effective greenhouse gas, but it's also methane that we are dealing with from the release of burning processes, especially in high northern latitudes, that contributes further to the concentration of -- high concentrations of greenhouse gasses. That pulse occurs immediately when the fire is happening, but also for a number of years after the fire, as the respiration of the soil increases and the carbon in those burns continues to be released at higher...

  • 11:32:07

    BEN-ACHOUREven after the fire.

  • 11:32:08

    LOBODAEven after the fire. And in high northern latitudes, we're talking about 30 years after the fire. There's more carbon that's being released to the atmosphere, that's being absorbed by the growing trees because the growing process is comparatively slow up in high northern latitudes so, though the new trees are absorbing carbon, the respiration from the soil is actually releasing more carbon that's being absorbed at the same time.

  • 11:32:35

    BEN-ACHOURSo climate change promotes wildfires, promotes greenhouse gasses, promotes climate change.

  • 11:32:40

    LOBODAIt's what we call a positive feedback loop.

  • 11:32:45

    BEN-ACHOURI'm Sabri Ben-Achour with "Marketplace" and you're listening to "The Diane Rehm Show." And if you'd like to join us, call 1-800-433-8850. Or send an email to You can find us on Facebook or send us a tweet. Mike, you were saying?

  • 11:33:05

    FLANNIGANWell, there's a couple of things. When a fire -- during the combustion phase, it also releases black carbon, pyrogenic carbon, charcoal, soot. And this is carried aloft by the winds thousands of kilometers and can be deposited on ice and, for instance, Greenland. And there's work by Jason Box and there's a website, And this causes a change in the reflectivity of the surface, we call albedo. And if you have something black, it absorbs the solar radiation, helps accelerate the melting process of ice and snow. So that's another aspect of the positive feedback.

  • 11:33:46

    FLANNIGANHowever, I would be amiss if I did not mention that there are some well-respected scientists who believe that forest fires actually have a cooling effect. And this is because of the change in albedo where, if you have a coniferous forest, much of the winter it's snow free and so it absorbs the solar radiation much more effectively than snow. If you have a large fire go through, then during the winter you have snow cover, which reflects solar radiation. And they figure that is enough to counteract the difference from the warming effect from greenhouse gas being released through combustion, decomposition and black carbon, et cetera, et cetera.

  • 11:34:27

    FLANNIGANSo, you know, this is still under study. And, in fact, part of this work is part of the ABoVE program that Tatiana's involved in, there's a number of projects. And one of these projects is looking at, you know, are forest fires actually causing warming or cooling?

  • 11:34:43

    BEN-ACHOURSo there's not a consensus there yet?

  • 11:34:45

    LOBODAIt's complicated, right? Because geography really matters. People say geography doesn't matter. Geography matters a lot. Where things happen matter a lot. It depends on what kind of forest burns, it will determine how long the albedo will have the cooling effect. If a dark, coniferous forest burned and it's then replaced by deciduous forest, over time, as the normal succession path for the spruce-fir forests, then albedo can provide a negative feedback, a cooling impact, for a long time period -- up to, I believe 60 years, was something that was quoted in Jim Randerson's paper.

  • 11:35:30

    LOBODAHowever in, for example, Russia, in the large forest, when larch burns, it's replaced by larch. There is no deciduous phase. So the time period over which the albedo can have the cooling effect is much shorter. We estimate it on the order of 10, 11 years. So depending on where the forest burned, it may counterbalance the release of greenhouse gasses or may not. We just need more time to study those.

  • 11:36:00

    BEN-ACHOURI'm Sabri Ben-Achour with "Marketplace" and you're listening to "The Diane Rehm Show." Mike, how much of the Fort McMurray fire is burning deep in the soil?

  • 11:36:15

    FLANNIGANWell, if I may, I'd like to go back to one of the questions you asked that I didn't answer and that's about the role of El Nino. And eventually I hope you're going to ask the role of climate change on this fire as well.

  • 11:36:29


  • 11:36:30

    FLANNIGANBut, El Nino, yes, it did play a role. And El Nino, for this part of the world -- and this was a major El Nino -- means warm and dry. And that's exactly the winter we had and the spring we've been having thus far. The El Nino is weakening and we expect probably a La Nina in the next few months. But warm and dry conditions, which lead to, you know, the weather factor and drying the fuels and, if you get ignition, away we go. So -- but that's not to say that that fire is a result of El Nino. But it contributed. But we have bad fire years when it's neutral conditions in the Pacific or La Nina, it doesn't really matter.

  • 11:37:11

    BEN-ACHOURComing up, your calls and questions on the threat of climate change to our boreal forests. We'll be right back.

  • 11:40:00

    BEN-ACHOURWelcome back. I'm Sabri Ben-Achour with Marketplace, sitting in for Diane Rehm. Mike Flannigan, he's a professor of wildland fire science at the University of Alberta, Mike, you were just about to connect climate change and the fire in Alberta right now.

  • 11:40:19

    FLANNIGANWell, I was expecting that question. So I never attribute any individual event to climate change. So I'm not going to say the Fort McMurray fire was a result of climate change. It's consistent with what we expect with climate change. We expect more fire, we expect more intense fire. That we do -- often how I try and explain it is without climate change, let's just say for illustration that there's 10 bad fires, okay, in the landscape. With climate change let's just argue that there's 15 bad fire years, so 15 bad fires.

  • 11:40:57

    FLANNIGANSo the fire that burnt Fort McMurray, is it fire number one through 10 or fire number 11 through 15? I don’t know, so, you know, it's hard to say. But it is consistent with what we expect with climate change, longer fire seasons, more fire, more intense fire, and so, you know, this is what we expect to see in the future.

  • 11:41:19

    FLANNIGANNow it's important to know that there's hundreds of communities across Canada in the boreal forest. I would rate Fort McMurray as a medium risk community because there's a lot of Aspen around town, and deciduous trees and less -- much less flammable than conifers. There's many places across Canada, Alaska and Siberia that are surrounded by conifers that are at much higher risk to burn.

  • 11:41:43

    FLANNIGANSo this isn't a one-off. You know, like yes, it's unprecedented in terms of A, the number of people evacuated, near 90,000 people, and also in terms of cost. This will be the costliest fire in the world, period. The Oakland fire was the most costliest fire, under $3 billion with inflation calculated in. This is going to far surpass that. But there's lots of other places at higher risk, and so it may be next week, may be next year, maybe three or four years, we'll see another community burn. It could be Alaska, it could Siberia, it could be Quebec, Ontario. You know, it's -- it's going to happen, it's just a matter of time.

  • 11:42:22

    BEN-ACHOURYeah, I guess it's worth pointing out, you know, you can't really ever point one fire and connect it to climate change, right, but you can connect rates. Is that right? Because I mean even if climate change, the worst-case scenario of climate change happens in the next 100 years, you still are not going to be able to say this fire was caused by climate change. You can say this rate of fires or these severity of fires is being caused by climate change. Is that right?

  • 11:42:46

    FLANNIGANExactly because fire is part of the natural environment. But what we can say is that in Canada, and this is true for the Western United States and Alaska, perhaps at different rates, and Siberia recently, in Canada our area burned has doubled in the last 40 years, and right now in Canada we burn about two million hectares, that's about the size of New Jersey, every year. So it's a lot of territory burns every year, but this has doubled from what it was in the early '70s at one million hectares.

  • 11:43:19

    FLANNIGANAnd, you know, we attribute this to human-caused climate change. So we can attribute the amount burning, the number of fires, the fire season, the fire intensity, we can attribute this to climate change but not an individual event like the Fort McMurray fire.

  • 11:43:32

    BEN-ACHOURAnd let's open the phones. We have Elaine from Middleburg, Virginia, calling. Hi Elaine.

  • 11:43:37

    ELAINEHello, I'm glad to ask you this question. First of all, how is the -- all of the persons affected very much what happening in the forest, and this in turn has affected very much the wildlife and particularly the wolves. And how many studies have been done since this fire started of how many wolves have actually perished?

  • 11:43:59

    BEN-ACHOURGreat question, Elaine, thanks. What about wolves? What about all the creatures?

  • 11:44:08

    FLANNIGANI'm a wildfire researcher. Unfortunately I'm not a wildlife researcher. And I really do not know the answer to that question.

  • 11:44:17


  • 11:44:18

    LOBODAI'm also a wildfire person, but for my Ph.D., I actually looked at the impact of fire on the Siberian tiger. So I don’t know about the wolves, but the tigers, in the Russian forests seem to be doing okay, because what's burning is usually not the habitat that they need. In the -- again the fire impacts are very complex. Some species can come out winners out of -- after the fire events. During the fire event, they lose part of the territory that they can use, but as the forest regrows, those deer and moose, particularly, who are browsers, and they really like young shoots from regrowing shrubs and trees, they find a better environment that was there before it got burned.

  • 11:45:15

    LOBODAWolves, I would assume as an apex predator, will also benefit from high density of prey. So when the fire event is happening, it's definitely a detriment but a short-lived one, and it can leave to more a -- lead to a more beneficial environment later on, over a period of 30 years, roughly.

  • 11:45:39

    BEN-ACHOURI mean, I would imagine that as an especially large fire is taking away habitat, though, for -- and possibly killing a lot of animals.

  • 11:45:51

    LOBODAAnimals are mobile, right. The fire has to be extreme, and some of what we've seen in Alberta and in other areas...

  • 11:45:56

    BEN-ACHOURIs extreme.

  • 11:45:58

    LOBODAIs extreme. The animals generally are not sitting at the fire line waiting for it to arrive. So some mortality is expected, but many can get out of the way quite safely. Boreal forest is quite a unique ecosystem because it had very large, contiguous stretches of forest that allows for the animals to migrate quite safely from one stretch to another. When the forest becomes fragmented, then loss of a chunk of habitat stresses the population that lives there beyond their capacity to recover. That can happen. But as long as the forest is contiguous, they have a chance to move around.

  • 11:46:47

    BEN-ACHOURWe have Andy calling from Wilmington, North Carolina. Andy, you're a forest ecologist. Thanks for calling.

  • 11:46:55

    ANDYThanks for taking my call. This is a great program. I'm -- this is a deviation somewhat from boreal forest. Here in the Southeast we have longleaf pine forest and bottomland swamp forest. And your panel's members were speaking a moment about CO2 production resulting from these wildfires. Are they -- I'm curious if they're working with the issue of wood pellets being burned to generate electricity and the consequence of CO2 production from that industry.

  • 11:47:34

    BEN-ACHOURThoughts, burning wood intentionally, as opposed to forest fires?

  • 11:47:40

    LOBODANot something that I study, so I don't think I can comment on that.

  • 11:47:45

    HUBBARDThe Forest Service has paid some attention but more along the lines of the sustainability of the production of the pellets and how that affects the forest and how it responds, not to my knowledge so much about the carbon.

  • 11:48:09

    BEN-ACHOURIs there a connection between forest fires and permafrost in the boreal forest? Tatiana?

  • 11:48:14

    LOBODAAbsolutely, absolutely. So if you can imagine, permafrost is the part of the ground that is frozen solid year-round.

  • 11:48:26

    BEN-ACHOURPermanently frosty.

  • 11:48:26

    LOBODAPermanently, right. So -- and it creates ecosystem that supports specific kind of forest, supports specific hydrologic regime, and the whole ecosystem wrapped around it. So when fires occur, particularly if they're stand-replacing fires and part of the organic layer is removed, it exposes the underlying soil to more warming, right, and as it's heated more by the sun, the permafrost starts melting.

  • 11:48:58

    LOBODAAnd one of the studies that I'm going to do this summer is I'm actually going to go out in the tundra, the North American tundra, and sample the depth of permafrost, the active layer thickness, in the old and new and recent single and repeated fires that occurred there over the last 40 years.

  • 11:49:19

    BEN-ACHOURYou know, so I'm hearing a lot of different, really interesting connections between forest fires and the changing forest. And, you know, you mentioned there was soot that can fall on ice somewhere else and change how the ground absorbs heat or doesn't absorb heat. But you've also said there are ways in which forest first don't necessarily contribute to climate change.

  • 11:49:43

    BEN-ACHOURWhen you sum all them up, do we know yet whether or how the world's boreal forests are affected by climate change and to what extent they're contributing to climate change?

  • 11:49:56

    LOBODAI would say it's an ongoing study. There are multiple studies that are going on around the world that are looking at the issue, and maybe in the next IPPC round of reports, or IPPC-like round, we can summarize the findings. Mike?

  • 11:50:13

    FLANNIGANSo, you know, one of the things I hear is that okay, so we're seeing more fire. Well, eventually the forests will disappear, and our fire problem will go away.

  • 11:50:26

    BEN-ACHOURI guess that's not funny, actually.

  • 11:50:31

    FLANNIGANSo but that's -- and it may be true. If we continue to have increasing fire, some species will not sexual maturity for seed production, and even those that sprout like Aspen, if you have repeated fire, eventually it won't be able to survive. But that doesn't mean our fire problem goes away. What will replace such forests? Well, shrubs and grassland. And many shrubs and grasslands can burn even more frequently than forests can.

  • 11:50:59

    FLANNIGANSo as long as there's vegetation and appropriate weather and ignition, we're going to have fire on the landscape, and we have fire globally. I mean, if you look at the global picture, about the size of India burns every year on our planet. So fire is part of our system. And Tatiana's right. It depends, you know. That's a common answer scientists use, but it's true. It depends on what exactly you're looking at, what scale, time and space to answer that question. But the boreal forest plays a vital role in our climate system, for wildlife, for diversity. You know, it's really important, and we're starting to see it being more fragmented with development.

  • 11:51:47

    FLANNIGANJames talked about the wildland urban interface. In Canada we're now talking about the wildland industrial interface because mining, resource extraction, they're fragmenting the forest, and we -- you know, we do have these swaths of contiguous forest, continuous forest, that are great for wildlife species, but now it's getting fragmented, and species like caribou are having problems, or at least some herds are.

  • 11:52:11

    FLANNIGANAn so there's a myriad of issues associated with the boreal, but the boreal -- the health of the boreal is a key component of the health of the planet.

  • 11:52:21

    BEN-ACHOURI'm Sabri Ben-Achour with Marketplace, and you're listening to the Diane Rehm Show. What about health effects? I mean, are there health consequences to giant forest fires like we're seeing?

  • 11:52:35

    LOBODAThere are massive health effects, if I can jump in for a second.

  • 11:52:38


  • 11:52:40

    LOBODASomething that we know is that pollutants that are emitted by wood burning and forest fires specifically are more toxic to the human lung than the same level of pollutions from different sources. So that smoke, the massive amount of smoke that comes off from large, intense boreal fires gets transmitted through the atmosphere and transported long ways. We -- I don't know if you remember, in 2003 I believe we had very large fires in Canada that reached all the way down here into Maryland.

  • 11:53:21

    LOBODAWe have smoke plumes and all that, which impacted our air quality. If you think about large fires in Europe and Russia in 2010 and the number of people who actually died as a result of the smoke inhalation and the adverse health effects that are caused by smoke inhalation, that was a very, very pronounced and massive impact.

  • 11:53:47

    BEN-ACHOURGo ahead, Jim.

  • 11:53:48

    HUBBARDWe're concerned about that, the smoke in particular, and the long-term exposure because these large fires do last longer. And so we'll have Western communities smoked in for 30 days at a time. That causes human health problems. And we've been working with the Center for Disease Control to examine what we can do with -- about this. We know we have to get people out of the way of it at times, but we don't know what kinds of effects it has on somebody that sits in smoke for 30 days at a time.

  • 11:54:23

    BEN-ACHOURWe have a question, I think it's up our alley, Jim. We have Kelly from Alexandria, Virginia. Kelly, go ahead, you're on the air.

  • 11:54:31

    KELLYHey, thank you for taking my call. Hey, I had a quick question. At least I know in the U.S., I'm not sure about Canada, but we used to burn, control-burn the undergrowth of the forest, for example all the fallen trees, leaves, brush, whatnot, and that seemed to have a good effect of keeping these large forest fires to a minimum and allowing us to be able to control them better once they do ignite. Is that some that we've quit doing, and is that possibly the reason that we have worse forest fires occurring? I'm not trying to minimize the effects of global warming, but is that one of the reasons why these fires are worse?

  • 11:55:06

    BEN-ACHOURGood question.

  • 11:55:06

    HUBBARDYea, we have not quite doing that in the United States, especially in the Southern United States. The Southeastern states do a lot of burning, probably eight million acres a year of prescribed fire. And that's necessary in the South because the regrowth under -- the understory of a forest, regrowth is fast in the South, and if you don't keep that down every two to three years, then you have more of a fire problem.

  • 11:55:37

    HUBBARDAnd climate change producing large fires, not just a Western issue in the United States. It's starting to show up more in the East, and that -- that prescribed burning of the fine fuels underneath the trees is critical to control. In the West it's more difficult, partly because of the development that's in the way and how that occurs in the West. Yes, we have development in the East, too, but how that occurs and under what kind of fuel conditions, we usually have to do more mechanical treatment prior to prescribed fire to be able to have a manageable fire in the West.

  • 11:56:18

    HUBBARDAnd we have more -- we have tighter burn windows, where we can actually do it and not have the smoke become a human health problem.

  • 11:56:29

    BEN-ACHOURMike, what kinds of stuff are you guys doing in Canada to limit wildfires?

  • 11:56:34

    FLANNIGANWell, I mentioned the Fire Smart Program, similar to the Fire Wise Program in the United States. So we are spending millions and millions of dollars on treating fuels around community. So that involves things like prescribed fire, where possible. But James is right. Our burning windows are really small, and the acceptance of smoke is really low around urban communities now.

  • 11:56:58

    FLANNIGANSo -- but there's mechanical treatment. Replacing the conifers, that's public enemy number one. And like sometimes...

  • 11:57:05

    BEN-ACHOURIn the cities, you mean, I presume?

  • 11:57:06

    FLANNIGANAround the cities, okay, so that fringe around the cities, reducing the fuel load, and we have spot fires. These spot fires can be carried more than a mile in distance. So you need to treat the fuels not just immediately but, you know, a fairly large swath around the community.

  • 11:57:25

    BEN-ACHOURMike Flannigan, professor of wildland fire science at the University of Alberta. Thanks to all of you. Thanks for listening. I'm Sabri Ben-Achour from Marketplace, sitting in for Diane Rehm.

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