Wildfires have returned to the Arctic tundra after a 10,000-year absence.
Researchers have quantified the amount of soil-bound carbon released into the atmosphere in the 2007 Anaktuvuk River fire in Alaska’s Brooks Range and found that it resulted in 2.1 million tonnes of carbon being released into the atmosphere.
The tundra has a carbon-rich, peaty soil and the ground itself is combustible. When the fire recedes, some of the soil is gone and the exposed permafrost is also covered by blackened ground, which absorbs more of the sun’s heat and could accelerate thawing.
“When the permafrost warms, microbes will begin to decompose that organic matter and could release even more carbon that’s been stored in the permafrost for hundreds or thousands of years into the atmosphere. If that huge stock of carbon is released, it could increase atmospheric carbon dioxide drastically,” University of Florida ecologist Michelle Mack said.