Nav: Home

Drying Arctic soils could accelerate greenhouse gas emissions

June 13, 2016

OAK RIDGE, Tenn., June 13, 2016--A new study published in Nature Climate Change indicates soil moisture levels will determine how much carbon is released to the atmosphere as rising temperatures thaw Arctic lands.

An international team led by Northern Arizona University scientists analyzed the results of 25 experiments from multiple research groups including the Department of Energy's Oak Ridge National Laboratory. The researchers had measured the release of greenhouse gases from incubated soil samples, which originated in field sites in Alaska, Canada and Russia, under a temperature increase of 10 degrees Celsius.

Researchers found that soils with plenty of oxygen from air released about 3.4 times more carbon than wetter soils with limited oxygen. Even accounting for the effects of methane--an extremely potent greenhouse gas produced by microbes in saturated, oxygen-free soils--oxygen-rich soils still released comparatively more carbon.

"It tells us that the tipping point is more toward when that soil becomes exposed to oxygen," ORNL coauthor David Graham said. "If the soils were to drain and dry, it would be a significant change that dramatically alters the carbon flux coming out of the soil."

The team's findings will help scientists refine models to predict future climate scenarios. Climate models can use the results to improve estimates of methane and carbon dioxide release under rising temperatures and changing soil moisture conditions.

"Models help us scale from the present to the future," ORNL's Colleen Iversen said. "It's one thing to say, 'What does the Arctic look like now and what are the implications for carbon feedbacks?' But we really want to know what it will look like at the end of the century. The only way we can get there is to have accurate processes in models that are predicting the future."

Recognizing the importance of soil moisture and hydrology in the Arctic will also guide future experimental research in DOE's Next-Generation Ecosystem Experiments Arctic project, which supported the three ORNL incubation studies. As NGEE-Arctic enters its second phase, one of the project' goals is to examine the extent to which Arctic soils will become wetter or dryer--a task complicated by the region's unique topography.

"A few centimeters can make the difference in whether the ground slumps and becomes wetter or ends up high and dry, by separating more from the water table," Iversen said. "There are also big ponds that might dry out over large areas as well as soils underlain by a network of ice wedges where warming could lead to a thermokarst, or a slumping, of the land surface as permafrost thaws and the ice wedges melt. So the wetting and drying of the Arctic is important to observe and model at scales ranging from a meter to multiple kilometers."

Scientists estimate that frozen high-latitude soils today contain nearly twice as much carbon as the atmosphere. The proportion underscores the need to better understand the Arctic's rapidly altering ecosystem, said ORNL's Stan Wullschleger, who leads the multi-institutional NGEE-Arctic effort.

"The Arctic is changing faster than any other environment," Wullschleger said. "It's highly sensitive to change and its feedback to the global system could be huge."
-end-
The study is published as "Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils." ORNL coauthors are David Graham, Colleen Iversen, Richard Norby, Taniya Chowdhury and Victoria Sloan. Support for the ORNL research was provided by DOE's Office of Science.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE's Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

DOE/Oak Ridge National Laboratory

Related Atmosphere Articles:

Primitive atmosphere discovered around 'Warm Neptune'
A pioneering new study uncovering the 'primitive atmosphere' surrounding a distant world could provide a pivotal breakthrough in the search to how planets form and develop in far-flung galaxies.
NASA's MAVEN reveals Mars has metal in its atmosphere
Mars has electrically charged metal atoms (ions) high in its atmosphere, according to new results from NASA's MAVEN spacecraft.
Northern oceans pumped CO2 into the atmosphere
The Norwegian Sea acted as CO2 source in the past.
Study opens new questions on how the atmosphere and oceans formed
A new study led by The Australian National University has found seawater cycles throughout the Earth's interior down to 2,900km, much deeper than previously thought, reopening questions about how the atmosphere and oceans formed.
How a moon slows the decay of Pluto's atmosphere
A new study from the Georgia Institute of Technology provides additional insight into relationship between Pluto and its moon, Charon, and how it affects the continuous stripping of Pluto's atmosphere by solar wind.
More Atmosphere News and Atmosphere Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...