Northern Wildfires: Underestimating Carbon Emissions from Boreal Forests

Recent research led by UC Berkeley highlights that wildfires in the northern boreal forests of Alaska, Canada, Scandinavia, and Russia may be releasing significantly more carbon into the atmosphere than previously estimated. This study reveals that these wildfires not only consume trees but also penetrate deep into carbon-rich soils, known as peat, which have accumulated carbon over centuries. The findings suggest that existing climate models may not adequately account for these underground carbon emissions, leading to a substantial underestimation of the climate impact of these fires.

We may be underestimating the true carbon cost of northern wildfiresSciTechDaily

The study, published in the journal *Science Advances*, involved a detailed analysis of 324 wildfires that occurred in Sweden in 2018. Researchers, led by postdoctoral scholar Johan Eckdahl, utilized a combination of national forest datasets and field measurements to create a high-resolution map of carbon emissions. They discovered that many global wildfire emissions models, which primarily rely on satellite imagery to assess visible flames, often overlook the slow-burning fires that release carbon from belowground sources.

We may be underestimating the true carbon cost of northern wildfiresSciTechDaily

For instance, in Gävleborg County, models overestimated emissions from high-intensity fires that were easily detectable from space. Conversely, in Dalarna County, where low-intensity fires burned into thick organic soils, emissions were underestimated by as much as a factor of 14. This discrepancy underscores the need for improved modeling techniques that consider the unique characteristics of boreal forest fires.

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Eckdahl emphasized the importance of recognizing that many significant fires may not appear dramatic from satellite views, yet they can smolder for extended periods, releasing vast amounts of ancient carbon. The research indicates that the impact of extreme fire seasons in northern regions is likely being underestimated, which could have profound implications for climate change projections.

We may be underestimating the true carbon cost of northern wildfires

The study's authors are now expanding their research efforts to fire-prone forests in the Western United States through the Western Fire & Forest Collaborative. While these forests may not have the same carbon-rich soil layers as those in the far north, factors such as local climate and vegetation types still significantly influence wildfire emissions. Eckdahl's ongoing work will focus on the role of soil microbes, including bacteria and fungi, in forest recovery post-wildfire.

We may be underestimating the true carbon cost of northern wildfiresSciTechDaily

Eckdahl stated, “By improving our understanding of how this element flows between the land and the atmosphere, we can better anticipate the impact of future fire regimes in a warming world and design smarter strategies to reduce climate risks on society.” This sentiment reflects the urgency of addressing the gaps in current wildfire emissions models.

We may be underestimating the true carbon cost of northern wildfires

• “Many of the fires that matter most for the climate don’t look dramatic from space,” — Johan Eckdahl, Postdoctoral Scholar, UC Berkeley

We may be underestimating the true carbon cost of northern wildfires

• “We may be severely underestimating the impact of the recent extreme fire seasons in these regions.” — Johan Eckdahl, Postdoctoral Scholar, UC Berkeley

We may be underestimating the true carbon cost of northern wildfires

• “Forests in the Lower 48 and those far up north may look very different, but they share the common currency of carbon,” — Johan Eckdahl, Postdoctoral Scholar, UC Berkeley

We may be underestimating the true carbon cost of northern wildfires

While the study provides critical insights into the carbon emissions from northern wildfires, there remains a lack of comprehensive data from regions like Siberia, where access to fire sites is challenging. This gap in data may further complicate the understanding of wildfire impacts on climate change.

We may be underestimating the true carbon cost of northern wildfires

In summary, the findings from UC Berkeley's research underscore the need for a reevaluation of how wildfire emissions are modeled, particularly in northern boreal forests, to better inform climate change strategies and policies.

We may be underestimating the true carbon cost of northern wildfires