Old carbon in permafrost: a new source of atmospheric carbon?


photo by Chris Linder

Billions of tons of organic carbon from plants and animals have been stored in permafrost soils for hundreds to thousands of years. As temperatures continue to warm, permafrost thaws, which could release large amounts of carbon dioxide and methane into the atmosphere, further amplifying climate change. A new paper, co-authored by Woods Hole Research Center scientist Sue Natali, seeks to quantify the amount of ancient carbon released to the atmosphere as the climate continues to warm.

“The release of old carbon is important for climate feedbacks because this carbon had been out of active cycling for hundreds to thousands of years. So, in essence, this represents a new carbon source to the atmosphere, similar to fossil fuel combustion,” said Dr. Natali.

The study, published this week in Nature Climate Change, found that as permafrost was warmed and thawed, more old carbon was released into the atmosphere. The findings are based on research collected from an Alaska tundra site where the ecosystem was experimentally warmed to examine how tundra ecosystems will respond under future climate scenarios. After thawing the permafrost, the team of researchers measured how much carbon dioxide was released from the tundra as well as the age of the carbon that was respired by plants and microbes as the soils decomposed.

Scientists studying carbon release from thawing permafrost suggest that additional carbon release will likely accelerate climate warming, which will, in turn, lead to additional thawing of frozen soil, creating an ongoing amplification of climate change.

Link to abstract »

WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the globe.