 |
|
Bad sign for global warming: Thawing permafrost holds vast carbon pool
September 04, 2008GAINESVILLE, Fla. --- Permafrost blanketing the northern hemisphere contains more than twice the amount of carbon in the atmosphere, making it a potentially mammoth contributor to global climate change depending on how quickly it thaws.
So concludes a group of nearly two dozen scientists in a paper appearing this week in the journal Bioscience. The lead author is Ted Schuur, an associate professor of ecology at the University of Florida.
Previous studies by Schuur and his colleagues elsewhere have estimated the carbon contained in permafrost in northeast Siberia. The new research expands that estimate to the rest of the permafrost-covered northern latitudes of Russia, Europe, Greenland and North America. The estimated 1,672 billion metric tons of carbon locked up in the permafrost is more than double the 780 billion tons in the atmosphere today.
"It's bigger than we thought," Schuur said.
Permafrost is frozen ground that contains roots and other soil organic matter that decompose extremely slowly. When it thaws, bacteria and fungi break down carbon contained in this organic matter much more quickly, releasing it to the atmosphere as carbon dioxide or methane, both greenhouse gases.
Scientists have become increasingly concerned about this natural process as temperatures in the world's most northern latitudes have warmed. Just last week, it was announced that the amount of sea ice covering the Arctic may reach a new low this summer. Meanwhile, there is widespread consensus that the highest latitudes will warm the fastest, a process already visible in the accelerated thawing of glaciers worldwide.
Two years ago, Schuur and two colleagues authored a paper in the journal Science estimating that 400,000 square miles of northeast Siberian permafrost contained 500 billion metric tons of carbon. For this new paper, scientists combined an extensive database of measurements of carbon content in different types of permafrost soils with the estimated spatial extent of those soils in Russia, Europe, Greenland and North America.
Schuur said the researchers estimated the carbon contained in permafrost to a depth of three meters, two meters deeper than many earlier estimates. Although permafrost depths vary greatly with location, basing the estimate on three-meter depth "better acknowledges the true size of the permafrost carbon pool," Schuur said.
The new estimate is important because it mirrors other climate change science suggesting that at a certain tipping point, natural processes could contribute significant amounts of greenhouse gases, supplementing human-influenced, industrial processes that release fossil fuel carbon, Schuur said.
"There are relatively few people living in the permafrost zone," Schuur said. "But we could have significant emissions of carbon from thawing permafrost in these remote regions."
How fast the permafrost would release its carbon is a hugely important question.
Schuur said the burning of fossil fuels contributes about 8.5 billion tons of carbon dioxide each year. Deforestation of the tropical forests and replacement of the forest with pasture or other agriculture is thought to add about 1.5 billion tons per year. How much permafrost will add will depend on how fast it thaws, but Schuur said his research indicates the figure could approach .8-1.1 billion tons per year in the future if permafrost continues to thaw.
With the Arctic warming and permafrost thawing, shrubs and trees are likely to grow on ground formerly occupied by tundra - indeed, such a transformation has already been observed in parts of Alaska, where some arctic tundra is becoming shrub land.
Because plants take in carbon dioxide and release oxygen, it might appear they could compensate for whatever carbon is released by the thawed permafrost. But Schuur said the amount of carbon stored in the permafrost is far greater than what is found in shrubs or trees.
For example, he said, a mature boreal forest may contain five kilograms per meter squared of stored carbon. But the same area of permafrost soil can contain 44 kilograms, and 80 percent of that could be lost over long-term warming. "The bottom line," he said, "is that you can't grow a big enough forest to offset the carbon release from the permafrost."
University of Florida
"It's bigger than we thought," Schuur said.
Permafrost is frozen ground that contains roots and other soil organic matter that decompose extremely slowly. When it thaws, bacteria and fungi break down carbon contained in this organic matter much more quickly, releasing it to the atmosphere as carbon dioxide or methane, both greenhouse gases.
Scientists have become increasingly concerned about this natural process as temperatures in the world's most northern latitudes have warmed. Just last week, it was announced that the amount of sea ice covering the Arctic may reach a new low this summer. Meanwhile, there is widespread consensus that the highest latitudes will warm the fastest, a process already visible in the accelerated thawing of glaciers worldwide.
Two years ago, Schuur and two colleagues authored a paper in the journal Science estimating that 400,000 square miles of northeast Siberian permafrost contained 500 billion metric tons of carbon. For this new paper, scientists combined an extensive database of measurements of carbon content in different types of permafrost soils with the estimated spatial extent of those soils in Russia, Europe, Greenland and North America.
Schuur said the researchers estimated the carbon contained in permafrost to a depth of three meters, two meters deeper than many earlier estimates. Although permafrost depths vary greatly with location, basing the estimate on three-meter depth "better acknowledges the true size of the permafrost carbon pool," Schuur said.
The new estimate is important because it mirrors other climate change science suggesting that at a certain tipping point, natural processes could contribute significant amounts of greenhouse gases, supplementing human-influenced, industrial processes that release fossil fuel carbon, Schuur said.
"There are relatively few people living in the permafrost zone," Schuur said. "But we could have significant emissions of carbon from thawing permafrost in these remote regions."
How fast the permafrost would release its carbon is a hugely important question.
Schuur said the burning of fossil fuels contributes about 8.5 billion tons of carbon dioxide each year. Deforestation of the tropical forests and replacement of the forest with pasture or other agriculture is thought to add about 1.5 billion tons per year. How much permafrost will add will depend on how fast it thaws, but Schuur said his research indicates the figure could approach .8-1.1 billion tons per year in the future if permafrost continues to thaw.
With the Arctic warming and permafrost thawing, shrubs and trees are likely to grow on ground formerly occupied by tundra - indeed, such a transformation has already been observed in parts of Alaska, where some arctic tundra is becoming shrub land.
Because plants take in carbon dioxide and release oxygen, it might appear they could compensate for whatever carbon is released by the thawed permafrost. But Schuur said the amount of carbon stored in the permafrost is far greater than what is found in shrubs or trees.
For example, he said, a mature boreal forest may contain five kilograms per meter squared of stored carbon. But the same area of permafrost soil can contain 44 kilograms, and 80 percent of that could be lost over long-term warming. "The bottom line," he said, "is that you can't grow a big enough forest to offset the carbon release from the permafrost."
University of Florida
Permafrost Current Events and Permafrost News RSSDried mushrooms slow climate warming in Northern forests
The fight against climate warming has an unexpected ally in mushrooms growing in dry spruce forests covering Alaska, Canada, Scandinavia and other northern regions, a new UC Irvine study finds.
Arctic soil reveals climate change clues
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.
IMPACTS: On the Threshold of Abrupt Climate Changes
Abrupt climate change is a potential menace that hasn't received much attention. That's about to change. Through its Climate Change Prediction Program, the U.S. Department of Energy's Office of Biological and Environmental Research (OBER) recently launched IMPACTS - Investigation of the Magnitudes and Probabilities of Abrupt Climate Transitions - a program led by William Collins of Berkeley Lab's Earth Sciences Division (ESD) that brings together six national laboratories to attack the problem of abrupt climate change, or ACC.
Thawing permafrost likely to boost global warming
The thawing of permafrost in northern latitudes, which greatly increases microbial decomposition of carbon compounds in soil, will dominate other effects of warming in the region and could become a major force promoting the release of carbon dioxide and thus further warming, according to a new assessment in the September 2008 issue of BioScience.
Tunguska catastrophe: Evidence of acid rain supports meteorite theory
The Tunguska event is regarded as one of the biggest natural disasters of modern times. On 30 June 1908 one or more explosions took place in the area close to the Tunguska River north of Lake Baikal. The explosion(s) flattened around 80 million trees over an area of more than 2000 square kilometres.
Permafrost Threatened by Rapid Retreat of Arctic Sea Ice, NCAR Study Finds
The rate of climate warming over northern Alaska, Canada, and Russia could more than triple during periods of rapid sea ice loss, according to a new study led by the National Center for Atmospheric Research (NCAR).
Methane Release Could Cause Abrupt, Far-Reaching Climate Change
An abrupt release of methane, a powerful greenhouse gas, from ice sheets that extended to Earth's low latitudes some 635 million years ago caused a dramatic shift in climate, scientists funded by the National Science Foundation (NSF) report in this week's issue of the journal Nature.
NASA study links Earth impacts to human-caused climate change
A new NASA-led study shows human-caused climate change has made an impact on a wide range of Earth's natural systems, including permafrost thawing, plants blooming earlier across Europe, and lakes declining in productivity in Africa.
Scientists head to warming Alaska on ice core expedition
The state of Alaska has the dubious distinction of leading the lower 48 in the effects of a warming climate. Small villages are slipping into the sea due to coastal erosion, soggy permafrost is cracking buildings and trapping trucks.
Indigenous peoples hardest hit by climate change describe impacts
Indigenous peoples have contributed the least to world greenhouse gas emissions and have the smallest ecological footprints on Earth.
More Permafrost Current Events and Permafrost News Articles
 | Frozen in Time: Permafrost and Engineering Problems by Siemon W. Muller Frozen in Time: Permafrost and Engineering Problems is a previously unpublished work by Siemon W. Muller (1900-1970), author of the first English-language book about perennially frozen ground. Professor Muller stopped working on the nearly completed manuscript in the early 1960s, and for reasons unknown set it aside about the time of the First International Conference on Permafrost in 1963. It... |
 | Permafrost Soils (Soil Biology) Vast areas of the soil ecosystem are permanently frozen or are unfrozen for only a few weeks in summer. Permafrost soils are of global interest since a significant increase in temperature is predicted for polar regions. This volume summarizes recent knowledge on various aspects of permafrost and permafrost-affected soils, including typical properties of these soils, the distribution and... |
 | Cryospheric Systems: Glaciers And Permafrost by C. Harris, J. B. Murton The introduction of the term periglacial by Lozinski in 1909 to describe the cold-climate conditions in the zone adjacent to, but beyond, the Pleistocene glaciers encouraged the separate development of geocryological and glaciological research. Geological and geomorphological processes at the interface between glaciers and permafrost have, as a result, been given less attention than they warrant,... |
 | Permafrost: A guide to Frozen Ground in Transition by Neil Davis |
 | Pipelines and Permafrost: Science in a Cold Climate (Carleton Contemporary) by Peter J. Williams This book addresses the need for a firm scientific basis for decision-making in the cold-region pipeline construction industry. In clear language it describes the behavior of permafrost and its effects on structures and terrain, and gives revealing accounts of the political and international aspects of related issues. The enlarged second edition maintains the easy-to-read, well-illustrated... |
| The Best of Science Fiction and Fantasy: Permafrost and Skin Deep by Roger Zelazny, Kristine Kathryn Rusch 1 Unabridged Cassette. Total playing time aprox. 90... | |
| Permafrost Canine (Bunshun Bunko) Japanese Language Book by Robin White | |
 | Size-mass allometry and biomass allocation of two larch species growing on the continuous permafrost region in Siberia [An article from: Forest Ecology and Management] by T. Kajimoto, Y. Matsuura, A. Osawa, A.P. Abaimov This digital document is a journal article from Forest Ecology and Management, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: We examined size-mass allometry and biomass allocation of two larch species (Larix gmelinii (Rupr.) Rupr. and Larix cajanderi... |
| Permafrost (CDROM full papers): Proceedings of the 8th International Conference on Permafrost 2003 by M. Phillips, S.M. Springman, L.U. Arenson The Proceedings of the Eighth International Conference on Permafrost contain an extensive overview of the most recent research in the fields of permafrost science and engineering on a global scale. The 230 contributions portray the rich diversity of permafrost-related research, which is being conducted worldwide. The themes covered include all major scientific, technical and engineering aspects... | |
| The Alaska Railroad between Anchorage and Fairbanks: Guidebook to permafrost and engineering problems (Guidebook / Division of Geological & Geophysical Surveys) by T. C Fuglestad |
| © 2008 BrightSurf.com |