Northern wildfires may be more dangerous for the climate than they appear. Researchers found that fires in boreal forests can burn deep into peat soils, releasing ancient carbon stored for hundreds or thousands of years. These slow, smouldering fires often look small from space, causing climate models to underestimate their emissions.
According to this report by Science Daily, wildfires sweeping through the vast boreal forests of Alaska, Canada, Scandinavia, and Russia could be having a larger impact on the climate than scientists once believed. A new study led by researchers at UC Berkeley suggests these northern fires may release far more carbon into the atmosphere than current estimates indicate.
The reason is that these fires do not only burn trees. In many boreal regions, flames can spread downward into thick layers of carbon rich soil beneath the forest floor. These soils, known as peat, contain partially decomposed plant material that has accumulated over hundreds or even thousands of years. Because the cold, wet conditions of the far north slow the breakdown of organic matter, these landscapes store enormous amounts of carbon underground.
According to the study, many widely used models that estimate wildfire carbon emissions fail to fully capture this underground burning. Most of these models rely heavily on satellite observations of visible flames and are based largely on fires that occur at lower latitudes. As a result, they may overlook slower, less visible fires that smolder deep within peat and organic soils.
“Many of the fires that matter most for the climate don’t look dramatic from space,” said study lead author Johan Eckdahl, a postdoctoral scholar in Berkeley’s Energy and Resources Group. “Peatlands and organic soils can smoulder for weeks to years, releasing enormous amounts of ancient carbon.”
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