Arctic soil reveals climate change clues

October 8, 2008

Frozen arctic soil contains nearly twice the greenhouse-gas-producing organic material as was previously estimated, according to recently published research by University of Alaska Fairbanks scientists.

School of Natural Resources & Agricultural Sciences professor Chien-Lu Ping published his latest findings in the Nature Geoscience and Scientific American Web sites. Wielding jackhammers, Ping and a team of scientists dug down more than one meter into the permafrost to take soil samples from more than 100 sites throughout Alaska. Previous research had sampled to about 40 centimeters deep.

After analyzing the samples, the research team discovered a previously undocumented layer of organic matter on top of and in the upper part of permafrost, ranging from 60 to 120 centimeters deep. This deep layer of organic matter first accumulates on the tundra surface and is buried during the churning freeze and thaw cycles that characterize the turbulent arctic landscape.

The resulting patterned ground plays a key role in the dynamics of carbon storage and release, Ping found. When temperatures warm and the arctic soil churns, less carbon from the surface gets to the deeper part of the soil. The carbon already stored in the deeper part of the soil is released into the atmosphere as carbon dioxide, methane and other gases.

Ping predicted that a two- to three-degree rise in air temperatures could cause the arctic tundra to switch from a carbon sink--an area that absorbs more carbon dioxide than it produces--to a carbon source--an area that produces more carbon dioxide than it absorbs. The more organic material stored in the tundra, the greater the potential effect of future releases, Ping stated.

"The distribution of the Arctic carbon pool with regard to the surface, active layer and permafrost has not been evaluated before, but is very relevant in assessing changes that will occur across the Arctic system," Ping wrote in his study. "Where soil organic carbon is located in the soil profile is especially relevant and useful to climate warming assessments that need to evaluate effects on separate soil processes that vary with temperature and depth throughout the whole annual cycle of seasons."

Source: University of Alaska Fairbanks

Explore further: Tundra study uncovers impact of climate warming in the Arctic

Related Stories

Researchers clarify impact of permafrost thaw

May 12, 2015

As the Earth's climate continues to warm, researchers are working to understand how human-driven emissions of carbon dioxide will affect the release of naturally occurring greenhouse gases from arctic permafrost. As the perennially ...

Thawing permafrost feeds climate change

April 23, 2015

Carbon, held in frozen permafrost soils for tens of thousands of years, is being released as Arctic regions of the Earth warm and is further fueling global climate change, according to a Florida State University researcher.

Old permafrost carbon released

August 19, 2013

Using indicator molecules, a team of researchers headed by ETH Zurich demonstrates that carbon stored in the Arctic permafrost is being mobilised in Eurasian river basins.

Recommended for you

Playing 'tag' with pollution lets scientists see who's 'it'

July 29, 2015

Using a climate model that can tag sources of soot from different global regions and can track where it lands on the Tibetan Plateau, researchers have determined which areas around the plateau contribute the most soot—and ...

'Carbon sink' detected underneath world's deserts

July 28, 2015

The world's deserts may be storing some of the climate-changing carbon dioxide emitted by human activities, a new study suggests. Massive aquifers underneath deserts could hold more carbon than all the plants on land, according ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.