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Related: About this forumCarbon dioxide biggest player in thawing permafrost
http://www.exeter.ac.uk/news/featurednews/title_517527_en.html[font face=Serif][font size=5]Carbon dioxide biggest player in thawing permafrost[/font]
[font size=4]Carbon dioxide emissions from dry and oxygen-rich environments are likely to play a much greater role in controlling future rates of climate change caused by permafrost thaw than rates of methane release from oxygen-poor wetlands in the Arctic, according to research by a scientist at the University of Exeter.[/font]
[font size=3]Dr Iain Hartley, an associate professor in the department of Geography, and his co-authors found that both temperature and soil conditions affected the quantity of carbon released from thawing permafrost. A 10 °C increase in soil temperature released twice as much carbon into the atmosphere, but even more importantly, drier, oxygen-rich soil conditions resulted in more than three times more carbon release than wetter, low oxygen soil conditions.
The study published in Nature Climate Change and led by Northern Arizona University Assistant Research Professor, Christina Schädel, analysed 25 Arctic soil incubation studies and discovered that the majority of that carbon emitted was in the form of carbon dioxide even in the low oxygen conditions, with only five per cent of the total anaerobic products being methane.
This means that even though methane packs 34 times the climate warming punch of carbon dioxide, methane fluxes were not high enough to compensate for the smaller total quantity of carbon released under low oxygen conditions in wet soils.
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[font size=4]Carbon dioxide emissions from dry and oxygen-rich environments are likely to play a much greater role in controlling future rates of climate change caused by permafrost thaw than rates of methane release from oxygen-poor wetlands in the Arctic, according to research by a scientist at the University of Exeter.[/font]
[font size=3]Dr Iain Hartley, an associate professor in the department of Geography, and his co-authors found that both temperature and soil conditions affected the quantity of carbon released from thawing permafrost. A 10 °C increase in soil temperature released twice as much carbon into the atmosphere, but even more importantly, drier, oxygen-rich soil conditions resulted in more than three times more carbon release than wetter, low oxygen soil conditions.
The study published in Nature Climate Change and led by Northern Arizona University Assistant Research Professor, Christina Schädel, analysed 25 Arctic soil incubation studies and discovered that the majority of that carbon emitted was in the form of carbon dioxide even in the low oxygen conditions, with only five per cent of the total anaerobic products being methane.
This means that even though methane packs 34 times the climate warming punch of carbon dioxide, methane fluxes were not high enough to compensate for the smaller total quantity of carbon released under low oxygen conditions in wet soils.
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Carbon dioxide biggest player in thawing permafrost (Original Post)
OKIsItJustMe
Jun 2016
OP
JonathanRackham
(1,604 posts)1. I can see how CO2 is released from permafrost.
I wonder if the problem is compounded because there can also be an increase in composting of the local vegetation?
Permafrost is natures freezer that suspends chemical reaction.
OKIsItJustMe
(19,938 posts)2. Drying Arctic soils could accelerate greenhouse gas emissions
(Please note, Oak Ridge National Laboratory. Copyright concerns are nil.)
https://www.ornl.gov/news/drying-arctic-soils-could-accelerate-greenhouse-gas-emissions
[font face=Serif][font size=5]Drying Arctic soils could accelerate greenhouse gas emissions[/font]
June 13, 2016
[font size=3]OAK RIDGE, Tenn., June 13, 2016A 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 Energys 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 methanean extremely potent greenhouse gas produced by microbes in saturated, oxygen-free soilsoxygen-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 teams 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, ORNLs Colleen Iversen said. Its 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 DOEs 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 dryera task complicated by the regions 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 Arctics rapidly altering ecosystem, said ORNLs Stan Wullschleger, who leads the multi-institutional NGEE-Arctic effort.
The Arctic is changing faster than any other environment, Wullschleger said. Its highly sensitive to change and its feedback to the global system could be huge.
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 DOEs 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. DOEs Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
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June 13, 2016
[font size=3]OAK RIDGE, Tenn., June 13, 2016A 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 Energys 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 methanean extremely potent greenhouse gas produced by microbes in saturated, oxygen-free soilsoxygen-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 teams 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, ORNLs Colleen Iversen said. Its 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 DOEs 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 dryera task complicated by the regions 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 Arctics rapidly altering ecosystem, said ORNLs Stan Wullschleger, who leads the multi-institutional NGEE-Arctic effort.
The Arctic is changing faster than any other environment, Wullschleger said. Its highly sensitive to change and its feedback to the global system could be huge.
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 DOEs 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. DOEs Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
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