Boreal Wildfires Release Massive Hidden Carbon, Study Shows
Northern wildfires may threaten our climate more than scientists previously thought. A new study from UC Berkeley reveals a hidden danger beneath the forest floor.The problem involves ancient carbon stores. Boreal forests across Alaska, Canada, Scandinavia, and Russia sit on thick layers of peat. These carbon-rich soils have accumulated plant material for hundreds or even thousands of years.When wildfires sweep through these regions, they don’t just burn trees. Flames spread downward into the soil. As a result, ancient carbon escapes into our atmosphere.
Satellites Miss the Real Story
Most climate models rely on satellite images to estimate fire emissions. However, this approach has a significant blind spot.Satellites only capture visible flames. They cannot detect slow, smoldering fires burning deep within peat soils. These underground fires can last for weeks or even years.Many of the fires that matter most for the climate don’t look dramatic from space,” explained Johan Eckdahl, lead author and postdoctoral scholar at UC Berkeley. “Peatlands and organic soils can smolder for weeks to years, releasing enormous amounts of ancient carbon.”
What the Sweden Data Revealed
The research team analyzed 324 wildfires that burned across Sweden in 2018. They published their findings in the journal Science Advances.Researchers combined detailed forest records with direct field measurements. They reconstructed exactly how much carbon each fire released. Then they created a detailed map of wildfire emissions.Local conditions mattered significantly. Climate, vegetation, and soil characteristics all influenced how much carbon escaped during fires.
Models Missed the Mark
The team compared their findings with six widely used global wildfire models. The differences shocked them.In some areas, models actually overestimated emissions. But in other regions, they dramatically underestimated the true numbers.For example, in Gävleborg County, intense fires burned through dry forests. Satellites captured these clearly, and models predicted higher emissions accurately.However, neighboring Dalarna County told a different story. There, lower intensity fires burned quietly into thick organic soil layers. Satellites barely noticed them. The models underestimated carbon emissions by up to 14 times.”Sweden is a very large country, but it’s quite small compared to Siberia and Canada,” Eckdahl noted. “We may be severely underestimating the impact of recent extreme fire seasons in these regions.”
