The Arctic - made up mostly of thick boreal forests - is arming faster than any other place on Earth. Over the last 10,000 years, forest fires there have become larger and more frequent. Biologist Michelle Mack studies Arctic fire history at Northern Arizona University's Science Lab. She's concerned the carbon dioxide released through intense fires in Arctic ecosystems is accelerating climate change.
Mack says, "One thing that's really unique about boreal forests is that the fire moves through the understory and it's burning both the mosses that are on the forest floor but it's also burning into the organic soils." Mack adds, "Boreal soils store at least a third of the soil carbon on this planet, and so if fires are burning into those soils, the emissions that are coming from the ecosystems are coming from soils burning."
What's more, these boreal soils, Mack explains, protect the cold permafrost beneath, which contains even more carbon. When the surface soils burn, the permafrost is exposed and begins to thaw.
"These are soils that have been frozen, in many cases, since the Pleistocene era where the carbon in those soils has been locked away from exchange with the atmosphere," Mack says. "So, fire removes that insulating blanket and then those soils warm up. And if those soils warm up and begin to decompose and release carbon to the atmosphere, there's a lot of carbon in those soils - twice as much carbon as is in the atmosphere."
Mack believes that understanding the impact of Arctic fire on global warming may lead to changes in how boreal forest fires are managed.
Brain food is produced by KNAU, Arizona Public Radio.