Fired up

In summer 2023, just a year ago, huge wildfires raged throughout eastern Canada. Smoke obscured the sun and fouled the air across the eastern U.S. and Canada. By the end of the year, more than 6,000 fires had torched an area larger than England. This summer, a large portion of Jasper, Alberta burned, reducing about a third of the Canadian resort town to rubble.

Events like this used to be shocking in this region, but it seems we are becoming used to — normalizing, in fact — the idea of “wildfire season” as more and more cities and towns go up in smoke.

I was talking to a colleague who owns some forested land in Michigan’s Lower Peninsula, recently, and I asked if he worries about wildfires. “All the time,” he said.

Could such devastating wildfires happen in Michigan? Does a warming climate make them more likely?

It’s getting hot in here

Burning forest fire in British Columbia in Kootenay National Park. (iStock.)

In this column, I use some of the techniques described in my Climate Blue series on storytelling to develop a fire scenario – or, at least, how I would think about the influence of a warming climate on fire in Michigan and the Great Lakes region.

First, I use what I call the “rule of continuity,” i.e., if it used to happen it will probably continue to happen. Wildfires always have been a part of the landscape in Michigan and the eastern U.S. It has been part of smart planning to consider the risk of fire to the built environment and natural landscapes, and that will continue to be the case. A warming climate does not introduce fire as something new. The warming, however, is expected to change things.

In a previous column on wildfire, I wrote about the roles of landscape and fire management, while factoring in the influence of a warming climate. I will repeat a couple of points here to help frame things.

Humans influence the amount of grasses, shrubs, and trees in a region by the actions we take. Most directly related to our decisions is where we build our communities and how we manage the interface between our towns and the natural, unbuilt spaces that surround them. We also have to consider how we manage fire. Do we suppress all fires? Do we practice controlled burns? Do we use fire to clear land?

Our landscape management decisions exert more influence on the potential for wildfires than a warming climate does. That means our landscape and building decisions are the best methods to limit and protect ourselves from wildfires.

Flaming out

Focusing on the climate perspective, in Michigan and the Great Lakes region warming is the most definitive aspect of climate change. A warming climate can be wetter, drier, or bounce back and forth between the two.

The large supply of water vapor to the Great Lakes region means we get a lot of rain. This has resulted in record flooding in recent years, which is good news for fire risk. When the fuels are wet, fire risk is reduced. In fact, in a recent paper by Victoria Donovan and coauthors, they document a decrease of wildfires in U.S. north central hardwood forests.

However, Michigan and the Great Lakes region do experience drought when the moisture supply to the region is disrupted. Because it is warmer, today’s droughts are unlike the ones we experienced in the past. Fuel, especially grasses and brush, dries out more quickly. Plus, during the warmer, wetter periods, those same grasses and bushes grow faster.

Growth followed by drought increases the amounts of fuel to feed the fires. This risk is realized in fires such as those in Jackson County, Mich., in spring of 2024.

So, episodically, as the climate warms, we can expect an increased risk of wildfires. And, of course, extended drought would lead to increased risk in forested lands.

East vs. west

And as it gets warmer in the west, we see an increase in dried vegetation — fuel for the fires.  The western part of North America is one place where we can document increases in fire that are related to the warming climate.

Michigan does not have that wet-season/dry-season pattern of the West Coast; we normally get precipitation all year around. And in recent years, we have been getting more precipitation. So, it is unlikely we will slip into a West Coast fire routine anytime soon.

But this wetting of the past decade is not guaranteed for our future. It is plausible, if not probable, that as warming continues, we will shift to a regime where evaporation becomes dominant over precipitation. This would dry more fuel and increase fire risk.

This is not our immediate situation. There are, however, parts of the Great Lakes region, including Michigan’s Upper Peninsula, where the warming is larger than other parts of the region and the precipitation increases are smaller. In addition, the U.P. is a low-population, heavily forested area. These factors warn us to be alert to increasing fire risk there.

What about those Canadian fires in 2023?

We have to consider how we manage fire, Rood says. Do we suppress all fires? Do we practice controlled burns? Do we use fire to clear land? (iStock.)

Large fires in eastern Canada have happened before. We can say that the season, size, and duration of the 2023 fires in Canada were influenced by the warmer and warming climate. As the climate is still warming, we cannot dismiss those fires as a one-off event. There will be more.

Sadly, there is little we can do in Michigan to avoid the smoke and air pollution from distant fires. The smoke from those enormous blazes can be detected around the globe in a matter of weeks.

Wildfire has been a threat in Michigan in the past but we are fortunate to have abundant water and moisture. The recent trends of precipitation and accumulation of water place wildfire as a lower risk here than flood and heat. That said, when fire conditions are present, a warming climate will increase the risk because of faster drying conditions. Unmanaged or encroaching grasses and shrubs are especially prone to fire during drought. And as forests are increasingly stressed by warmer climates, they often are replaced by more flammable plants.

Other parts of the eastern U.S. and Canada will experience greater increases in wildfire risk than Michigan and the Great Lakes. Many states in the eastern U.S. are heavily forested. During extended drought, the potential for large fires increases. Interestingly, the greatest wildfire presence in the East is in Florida and along the Gulf of Mexico. The forests there feature abundant shrubby undergrowth, and they are in a location with the most frequent lightning strikes.

Scenarios that consider drought, fire, and fire prevention are part of a responsible plan to address adaption to the warming climate. Looking beyond 10, 20, or 30 years, it is essential to pay attention to changes in the balance of precipitation and evaporation, because the more it warms the greater the fire risk. In all circumstances, fire-informed management of the landscape is critical, especially in highly populated areas. It is up to us to make sensible decisions about where and how we build.