Arctic Wildfires Release Carbon Stored for Thousands of Years

An analysis of burned Arctic and boreal soil samples reveals deeper combustion than anticipated, suggesting that fires raging in these latitudes contribute more to climate warming than previously thought.

Vicious Circle

In Arctic climates, vegetation grows more slowly, and its remnants can accumulate in the soil as peat over millennia, making substantial carbon sinks. New analyses indicate that the situation is changing due to the intensification of fires in the region.

Drill cores taken from the most affected areas reveal rapid burning of surface vegetation, which triggers a slow and prolonged combustion of ancient organic matter stored in the soil, resulting in the release of large amounts of soot, or black carbon, and CO2 into the atmosphere.

As the authors of the new study explain, presented at the latest meeting of the European Geosciences Union, in addition to absorbing solar radiation, which amplifies atmospheric warming, black carbon can settle on ice or snow, darkening their surface and significantly increasing their melt rate.

A study of soils around the Arctic and boreal forests has found that some wildfires are releasing carbon stored over millennia, meaning higher CO2 emissions than assumed https://t.co/qzKsV3avbn

— New Scientist (@newscientist) May 21, 2026

Millennia-old soil sections go up in smoke

Not surprisingly, the team found that the age of the released carbon varied by environment. Overall, higher latitudes involve shallower soils with organic matter accumulating closer to the surface.

Thus, in the Northwest Territories (Canada), fires release carbon stored for 400 years. In Greenland, the burned soil layer reaches a depth of 10 to 15 centimeters, implying the release of carbon aged between 560 and 1,000 years. In certain boreal forests of Quebec, the combustion affects soil sections up to 5,000 years old.

According to Sandy Harrison of the University of Reading, with the intensification of climate change, this worrisome phenomenon is expected to grow. The next step will be to precisely estimate the amount of ancient carbon released by Arctic forest fires.

A few months ago, a study had shown that boreal forests were migrating rapidly northward.