Arctic Science Explained: Wildfires

April 12, 2022
By Liz Weinberg

By Katherine Schexneider

Welcome to Arctic Science Explained! Each month, IARPC Collaborations community member Katherine Schexneider breaks down a topic related to Arctic science. If you have a topic you’d like to see featured, please email web@iarpccollaborations.org. This month, Katherine takes on Arctic wildfires.

Over the past several years, images of destructive wildfires in the western states have become almost common. For example, the 2018 Camp Fire in California took 85 lives, burned 153,336 acres, and wiped out 18,804 buildings, at a total cost of some $16.65 billion. But what many people don't realize is that Alaska, too, has seen an increase in wildfires in recent years. While there are fewer buildings per square mile at risk, growing wildfires put Alaska ecosystems in the crosshairs.

I’ll discuss four topics here to provide a framework to get you started: wildfire basics, how climate change influences wildfires, technology used to manage fires, and how ecosystems are affected. Let’s get started.

large plume of smoke rising from the ground

A column of smoke rises from the 2016 Marie Creek fire in Yukon-Charley Rivers National Preserve. Photo: Yasunori Matsui/NPS

The basics. While humans cause most fires by number, lightning causes the greatest damage by acreage. In Alaska, the geographic areas of concern are the boreal (subarctic) forests, which span much of the state’s interior below the North Slope. Black spruce trees are the principal fuel source.

Wildfires are actually a normal event in the life cycle of the boreal forest, naturally turning over the vegetation, removing the old and enriching soil for future growth. However, the frequency and severity of fire events has increased dramatically in recent decades. We’ve gone well past a steady cycle of death and renewal to one where the balance is shifting to loss of vast areas of forest. What was once an occasional, expected climate phenomenon is becoming a routine and damaging presence on the landscape.

It’s not only the trees that are burning. Peat, the boggy soil of boreal and Arctic tundra areas, can catch fire if it dries out, and when it does burn, it releases a tremendous amount of carbon into the atmosphere. To make matters worse, peat can smolder undetected through a winter season and then burn visibly as temperatures rise in the spring. Low-intensity peatland fires, however, can escape satellite detection, hindering our ability to map fire activity and measure its carbon release.

a close-up of wood with a charred pattern on it

A wildfire left this burn pattern on a weathered spruce tree near Birch Creek Wild and Scenic River. Photo: Jim Herriges/BLM

Climate. Global warming plays an unequivocal forcing role in Alaskan wildfires. Increased temperatures have made the land hotter and drier, so what were once damp soils and trees are now dry and ready for ignition. Scientists have tracked the increase in burned area over the past four decades, as described in the 2020 Arctic Report Card, and note that sporadic large fires account for the bulk of the damage. We can trace this again to climate: with so much forest area now hot and dry, and lightning storms occurring more frequently, fires can start and spread more easily.

While fire frequency and severity are both on the rise, there is great variability from season to season and among different locations with similar geographic features. This makes accurate prediction tricky.

mosaic of burnt and unburnt areas of tundra with smoke plumes rising

Fire smolders in the tundra of Noatak National Preserve in 2012. Photo: Alaska Fire Service

Satellites and models. Satellite imagery and mathematical models have dramatically enhanced our ability to assess damage from extinguished fires, monitor them in real time, and predict and plan for future fire events.

satellite image of alaska and siberia with gray smoke obscuring much of the land

A satellite image taken in 2015 shows smoke from wildfires in Alaska. Actively burning areas are outlined in red toward the right side of the image. Photo: Jeff Schmaltz/MODIS/NASA

Impacts. One of the key effects of the increase in wildfires is that it provides an additional source of carbon to the atmosphere. Trees store carbon in their roots, trunks, branches, and leaves, and fires release this carbon. If trees die during the fire, they can no longer take up additional carbon as they grow. Additionally, fires thaw permafrost. Like burning trees, thawing permafrost releases its carbon into the atmosphere.

Another key effect of increased wildfire in the boreal forest is that it changes overall ecosystems with the loss of conifer forests (made up of spruce, pine, and similar trees) and potential shift to deciduous and even shrubland areas. These new ecosystems may no longer provide the same habitat for animals and plants.

Fires also have direct impacts on people. Ecosystem shifts may impact people’s ability to find food through subsistence harvest. With the loss of trees, riverbanks may erode, increasing the sediment in waterways. And the smoke from fires can have major impacts on air quality.

Finally, Arctic wildfires affect more regions than just the far North. What happens in the Arctic doesn't stay in the Arctic—so although the fires in Alaska may seem far away to those in the Lower 48, we will still be affected. Increased carbon due to fires causes more warming across the planet. That warming will lead to more fire—and other impacts—throughout the world. So, these fires in what we tend to think of as remote areas impact an increasingly fragile land, and us to the south, and really, the whole planet.

person kneeling with their hands deep in tundra soil

An ecologist measures soil temperature and depth of organic soils after fire. Photo: NPS

Learn more from the links below:

Katherine Schexneider is a retired US Navy physician who now does volunteer work in Arctic research and climate change.

Note: Views expressed in this article are the author’s and do not necessarily reflect the views of the IARPC community.

Request an account

Join scientists from Federal, State, academic, NGO, and industry organizations working to accelerate the progress of Arctic research.

Membership suggestions are subject to approval and adherence to the IARPC Collaborations code of conduct.

IARPC Collaborations
Contact

Liz Weinberg
Web Manager & Community Coordinator
liz@iarpccollaborations.org
(503) 893-8910