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: Why thawing permafrost matters

Related Stories

Why thawing permafrost matters

January 12, 2018

In Bethel, Alaska, walls are splitting, houses are collapsing, and the main road looks like a kiddy rollercoaster. In the coastal town of Kongiganak, sinking cemeteries prevent Alaskans from burying their dead in the ground. ...

Streams can be sensors

December 29, 2017

Scientists at Michigan State University have shown that streams can be key health indicators of a region's landscape, but the way they're being monitored can be improved.

Meadows beat out shrubs when it comes to storing carbon

November 23, 2017

Excess carbon dioxide, emitted by burning fossil fuels like coal and petroleum, is one of the most important factors in driving global warming. While the world is focused on controlling global warming by limiting these emissions, ...

Sunlight stimulates microbial respiration of organic carbon

October 17, 2017

Sunlight and microbes interact to degrade dissolved organic carbon (DOC) in surface waters, but scientists cannot currently predict the rate and extent of this degradation in either dark or light conditions. A recent study ...

Could the peatlands of Congo be a carbon bomb?

November 8, 2017

Gruelling talks are unfolding in Bonn for implementing the UN's Paris Agreement on climate change, but many kilometres (miles) away, there are fears that any progress may be wiped out by a lurking carbon threat.

Recommended for you

Weather anomalies accelerate the melting of sea ice

January 16, 2018

In the winter of 2015/16, something happened that had never before been seen on this scale: at the end of December, temperatures rose above zero degrees Celsius for several days in parts of the Arctic. Temperatures of up ...

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.