Climate change fans deep-burning fires in Alaska
* Longer burning season means fires burn deeper into soil
* Deep fires release ancient stored carbon into atmosphere
* Interior Alaska goes from carbon sink to carbon emitter
By Deborah Zabarenko, Environment Correspondent
WASHINGTON, Dec 5 (Reuters) - Climate change is fanning longer- and deeper-burning fires in interior Alaska, changing the area from a carbon sink -- where planet-warming gases are stored naturally in the soil -- to a carbon emitter, scientists reported on Sunday.
The shift has occurred within the last 10 years and is due in large part to a longer burning season, according to a study published in Nature Geosciences.
The research was released at the start of a second week of international climate change negotiations in Cancun, Mexico.
When fires burn late into the season, past the end of July in northern latitudes, they don't just burn what's on the surface, but go deep into the soil where plant matter and other biomass have accumulated over thousands of years, said Merritt Turetsky, the study's lead author.
At some locations in interior Alaska, this accumulated biomass is as much as 26 feet (8 metres) deep, and is where climate-warming carbon has been stored. When it ignites, the carbon is emitted into the atmosphere. Continued...