Thawing permafrost releasing more carbon than previously thought

July 3 (UPI) -- The problem of thawing permafrost is worse than climate scientists thought. New research suggests previous studies have underestimated the rate at which thawing permafrost is releasing carbon into the atmosphere.

Thawing permafrost is one of the many negative feedback loops caused by global warming. As temperatures rise, more and more frozen tundra melts, releasing previously trapped carbon into the atmosphere and accelerating climate change.

The new findings build on researchers' ongoing efforts to track carbon storage and carbon cycling in Arctic ecosystems.

"This study was novel because we used new methods to directly track the soil carbon losses, and they were much higher than we previously thought," Ted Schuur, a professor of ecology at Northern Arizona University, said in a news release. "This suggests that not only is carbon being lost through greenhouse gases directly to the atmosphere but also dissolved in waters that flow through the soil and likely carried carbon into streams, leaves and rivers."

Scientists established a consistent relationship between the amount of carbon and ash content in the Alaskan soil, allowing them to use the soil's mineralogy as a proxy for tracking soil carbon changes over time.

The approach revealed an annual loss of 5 percent of soil carbon.

The study is bad news for the planet's carbon reserves, more than a third of which are located in frozen tundra. Researchers estimate 5 to 15 percent of the soil carbon sequestered in permafrost could be relinquished to atmosphere by the end of the century -- a development that would no doubt lead to accelerated warming.

"Our results demonstrate the potential for repeated measurements that quantify changes in soil carbon across the entire permafrost region to better understand its environmental fate," researchers wrote in the new study, published this week in the journal Nature Geosciece. "An effort such as this is a critical and currently overlooked link to determine the magnitude of the terrestrial permafrost carbon to climate change."