A Conversation with Jed O. Kaplan – Climate Change & Wildfires

A Conversation with Jed O. Kaplan – Climate Change & Wildfires

By Jed O. Kaplan 21 August, 2024

Wildfires are raging like never before. What's supercharging them? We sit down with Kaplan, Professor at the University of Calgary, to find out the key ingredients, the impacts climate change is having & what can be done

There’s no doubt that wildfires today are becoming increasingly severe. According to Nature, 2023 (the hottest year on record) facilitated destructive wildfires on six continents. Canada was ravaged by record-breaking wildfires, while extreme fire weather resulted in catastrophic fires in Hawaii, the Mediterranean, central Amazonia and central Chile. We sit down with Jed O. Kaplan, Professor at the University of Calgary, to find out why wildfires are becoming more extreme, what are its key ingredients, predictability & preparedness plus more.

CWR: Thank you for chatting with us Jed. For those of us who don’t understand how wildfires work, can you give us a quick rundown? What are the key risks and how are factors like climate change now supercharging these wildfires?

Jed O. Kaplan (JK): The key ingredients for wildfires are fuel, moisture and ignition sources. You cannot have fire if you don’t have anything to burn. You also won’t have a fire if the fuel is there but it’s too wet, and if there’s also nothing there to start the fire. So those three ingredients are essential for wildfires to occur.

The key ingredients for wildfires are fuel, moisture & ignition sources

When we think about the relationship between those three ingredients and climate change, one of the most important relationships is to do with moisture. In ecosystems where there is enough fuel to burn, for example in many forest ecosystems, as earth’s climate or regional climate gets hotter, fuels which constitute mainly of dead vegetation – like dried out grasses that are at the end of their growing season, dead trees or shrubs etc., but even living vegetation to some degree, those fuels dry out faster as it gets hotter. Because this, systems become more vulnerable to large scale fires.

As it gets hotter, ‘fuels’ (mainly of dead vegetation) dry out faster = systems more vulnerable to large scale fires

Climate change may also directly influence wildfire ignitions, but not as much. The two sources of wildfire ignitions are lightning and humans. I would say the link between human activities in terms of wildfire ignitions and climate change would be tenuous. Perhaps some people are spending more time outside, but I don’t think that would be very big issue. In terms of the amount of lightning, which is occurring, there may be some evidence that show there’s more lightning occurring over the last decade or so that could be related to climate change. However, that is more closely linked to rainfall where there’s a lot of lightning. As you know Hong Kong has lots of thunderstorms, but those thunderstorms are almost always accompanied by very intense rainstorms. The main point I want to make is that more lightning does not necessarily mean that there will be more wildfires because more lightning can also be associated with more or heavier rainstorms, which then lead to wetter conditions, which means that the fuel is not available to catch on fire.

CWR: Wildfires also transform forests, our vital carbon sinks, into super-emitters. How problematic is this feedback loop? And why does it sometimes take months to put out these fires?

JK: What wildfires do is return carbon to the atmosphere much more quickly than they otherwise would under conditions without fire. The biosphere and atmosphere are linked in the natural cycle, where carbon is taken up into plants and then gradually released through microbial decomposition of dead material. There are many terrestrial ecosystems that are adapted to fire, in fact, there are ecosystems that wouldn’t exist without fire, like many grasslands and savannas. So they need fire as a precondition of their ecology.

Warmer temps also means longer fire seasons

On the other hand, as a result of these warmer conditions, we are seeing longer fire seasons. Warmer temperatures mean that, again using the example of Hong Kong, the dry season is overall becoming warmer. The dry season is maybe not becoming longer, but the period in which you could have fires burning is becoming longer because the typical cool winter weather is becoming less common. We’re having more warmer dry winters. In other parts of the world, if you think about the temperate latitudes and boreal latitudes, where we’re starting to see year after year, these large fires, the reasons why this is happening are similar. Overall, warmer temperatures are leading to drier fuels. And those warmer and dry seasons is lasting longer.

In many areas, not possible to control wildfires because too remote

And so why do fires burn for many months? In many areas, it’s not possible to control wildfires aggressively because they’re in regions that are too remote. It’s just simply not possible to have lots of firefighters and equipment standing by to put out or control fires. So the longer the fire season lasts (and by fire season, I mean that period of the year when it’s generally warm and possibly also dry), the longer the fires will burn.

CWR: Clearly, it’s important to have reliable wildfire forecasting and predictive models. Are you doing anything on this front? What are the current challenges and opportunities?

JK: There are lots of great opportunities now, especially when we start thinking about how we as humans can try to promote the development or maintenance of ecosystems that are more resilient to wildfires. Through that we can hypothesize many different ideas about what’s important and what’s really the major control on wildfires in a certain region; is it the fuel, moisture or ignition sources?

If you think it’s ignition sources, then there could be various types of policy interventions that try to encourage the public to be more careful with fire. If it’s the fuel, then there are various kinds of interventions that we as humans can do to mitigate the build-up of fuels that could potentially lead to catastrophic wildfires. For example, using managed fires, so we can light fires on the landscape during a season when it’s a cool or wet, during periods when we’re likely to avoid sort of catastrophic fire, and that allows underbrush, grass and dead material to burn off in a way that doesn’t get out of control.

Forms of harvesting & managed burning are ways of increasing the resilience of ecosystems

This is increasingly being explored and practiced in many parts, particularly in Australia, Canada, United States, Portugal and a few other countries that are really wildfire prone. Then there are places in the world like India, Cambodia, and other parts of Southeast Asia and Australia, where traditional wildfire management or traditional land management that used fire is still being practiced, and all of these land management practices including various forms of harvesting and managed burning are ways of increasing the resilience of ecosystems to climate change.

Predictive modelling allows us to explore lots of different potential management practices and scenarios in terms of the outcomes that they might lead to, without having to commit to harvesting trees or grasses or lighting landscapes on fire. There is a risk with climate change when we think about practices that were historically beneficial in terms of ecosystem management, they might not be anymore, because current and ongoing future climate changes are taking us outside the envelope of climate that made that system appropriate in the past.

Predictive modelling can explore potential mgmt practices & scenarios but climate change is taking us outside the envelope making past conditions not viable

For example, you might say historically this landscape burned every five years, therefore, let’s reapply fire to this landscape every five years. But that might be bad idea now, because maybe hotter drier summertime conditions are making it too dangerous to start lighting fires every once in five years. Or maybe it will mean droughts during summer is leading to a lack of regeneration of vegetation in a certain place. Therefore, we can use predictive models as a tool to sort of explore lots of different “what if scenarios” – what if we light more fire, what if we harvested more vegetation, what if we fragmented the landscape by having agroforestry or smallholder agriculture mixed with forest, will that make it more resilient or not. Water resources or agricultural productivity, all of these different things are perfect problems that you can start to explore by using modelling.

CWR: What lessons can be learned from how other countries are managing wildfires? And if you were to give one piece of advice to governments and policymakers what would it be?

JK: Right now, there’s a lot of interest in the restoration of Indigenous fire and in learning from places where traditional forms of fire management are still practiced, particularly in the Global South. I think there are some great examples from South America, Africa and Australia, of how human use of fire makes ecosystems more resilient to catastrophic wildfires or helps avoid catastrophic wildfires.

We’re in a great place right now in terms of the increased interest and knowledge about traditional fire management practices, and even changes or adaptation to legislation to allow traditional fire management practices to be reintroduced to landscapes where they were banned, which is typically Western countries. Most Western countries up until even the late 20th century, considered all wildfire to be bad and therefore banned managed burning.

Two priority areas:

1) more research needed as fire is a complex phenomenon that occurs at a range of temporal/spatial scales

2) look at longer horizons – what’s going to happen in the next 50-100 yrs

In terms of which countries are really leading the way, there’s great stuff being done in Australia and in the United States, both in temperate tropical and subtropical environments. You may remember a couple of years ago there was really devastating wildfire that burned down the main town on the island of Maui, Hawaii. Because of that there’s a lot of interest now and figuring out on how traditional wildfires can be brought back to these landscapes that were set aside for cattle ranching for century or more ago. That would help to avoid the kind of catastrophic fire that we saw there.

For advice to policy makers, I would give two priorities. One is climate change really is changing wildfire occurrence and behaviour, and statistics are beginning to show that this is very obvious now. We are seeing sort of year after year of record-breaking amount of area burned, and part of that is related to climate change induced changes in fuel moisture, lengthening of the fire season and so on. This is clearly becoming an issue that cannot be ignored. And to their credit, many of the most fire-affected countries are not ignoring it. However, we do need to promote more research because fire is a complex phenomenon that occurs at a range of temporal and spatial scales – everything down from seconds and square meters, right up to hundreds of square kilometres and decades to centuries.

And two, while it’s important to be thinking operationally about how to manage wildfires today or this season, and how can we mitigate wildfires next year or in the next 5 to 10 years, we should also be thinking about what’s going to happen in the next 50 to 100 years. Are wildfires going to take our ecosystems into completely new places that we might not expect?

CWR: Clearly hotter weather in the future could drive more wildfires. You’ve mentioned Hong Kong a few times throughout this interview, should we be worried since it’s getting hotter here as well? Do you have any advice on this front?

JK: Wildfire is not a big research or policy topic in Hong Kong although more than 5% of the natural areas of Hong Kong burn every year. If one spends much time in the natural areas of Hong Kong, and knows something about fire ecology, it will be easy to recognize that almost every part of Hong Kong has been impacted by wildfires over the last 50 to 75 years.

Almost every part of HK’s been impacted by wildfires in the last 50-75 yrs but there’s limited knowledge & research

This is something we must think about when it comes to protecting the natural environment and adapting to ongoing and future climate change. Hong Kong and neighbouring parts of Southern China and Southeast Asia are areas where we know relatively little about how wildfire works much less than we do for places like Australia or Portugal or the United States. So, there’s really a need to do much more research in this direction. I would encourage local and regional governments to promote efforts to better understand how wildfires behaves and how their worst impacts could be mitigated in the future.

Regional govts should promote efforts to better understand fires & how to mitigate their worst impacts in the future

There is no evidence that there is more lightning now than there was in the past. Lightning-ignited fires are caused every year and have for hundreds of millions of years. Contemporary climate change is affecting the condition of the fuels (dryness), which is compounded by land management policy that led to many decades of heavy fire suppression and fuel buildup that caused the fires in Jasper to be particularly dramatic.

It is important to understand that we do not expect climate change to lead to more lightning strokes causing fires; what is happening is the same amount of lightning is leading to bigger and more intense fire because of drier fuels and land management history that allowed fuels to build up.

Further readings

• Heat Waves Hit the Poor Hardest – Heatwaves are among the deadliest disasters and poorer countries will be 2-5x more exposed to them by 2060, which risks $ billions. Sadegh, Abatzoglou & Alizadeh share more key findings from their research
• Rising Temperatures, Melting Ratings – 63 countries will suffer climate-induced rating downgrades in the world’s first climate smart sovereign rating simulation. More key findings from Dr Klusak, Dr Agarwala, Burke, Dr Mohaddes & Dr Kraemer
• Rivers are Running Dry Today – Rivers are our lifelines; they support cities, food & economies for centuries. This summer they were tested with severe drought/floods – will they fail? CWR’s Tan & Lam dive into challenges facing 5 major river basins that are the industrial/agricultural heartlands for China, Pakistan, US and Europe.

More on Latest

• 5 Ways Heat Can Kill — It’s hot, it’s bad & it’s here to stay, killer heat has arrived. It claims nearly half a million lives each year & it could get worse as our planet continues to warm. But how does heat kill? CWR’s Chai shares 5 ways
• If Earth gets sick, so do you – Earth’s growing fever has repercussions for human health. What should we be worried about? How is climate change changing the transmission of >20 tropical diseases? Are our brains at risk? Marley from The Conversation covers these questions and more
• Cooling Equipment: Keeping Us Cool but Heating Up the Planet – Ever think about the hidden costs of blasting your AC? Turns out it’s worse than just soaring energy bills. CWR’s Lam unpacks why our cooling habits could be warming our planet faster