Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Permafrost threatened by rapid melt of Arctic sea ice

11.06.2008
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.
The findings raise concerns about the thawing of permafrost, or permanently frozen soil, and the potential consequences for sensitive ecosystems, human infrastructure, and the release of additional greenhouse gases.

"Our study suggests that, if sea-ice continues to contract rapidly over the next several years, Arctic land warming and permafrost thaw are likely to accelerate," says lead author David Lawrence of the National Center for Atmospheric Research (NCAR).

The study will be published Friday, 13 June, in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

The research, conducted by scientists from NCAR and the National Snow and Ice Data Center (NSIDC), was spurred in part by events last summer, when the extent of Arctic sea ice shrank to more than 30 percent below average, setting a modern-day record.
From August to October last year, air temperatures over land in the western Arctic were also unusually warm, reaching more than 2 degrees Celsius (4 degrees Fahrenheit) above the 1978-2006 average and raising the question of whether or not the unusually low sea-ice extent and warm land temperatures were related.

To investigate this question, Lawrence and his colleagues analyzed climate change simulations generated by the NCAR-based Community Climate System Model. Previous analysis of these simulations suggested that a sustained period of rapid ice loss lasting roughly 5 to 10 years can occur when the ice thins enough.
During such an event, the model revealed, the minimum sea-ice extent can drop by an area greater than the size of Alaska and Colorado combined.

The team finds that, during episodes of rapid sea-ice loss, the rate of Arctic land warming is 3.5 times greater than the average 21st century warming rates predicted in global climate models. While this warming is largest over the ocean, the simulations suggest that it can penetrate as far as 1500 kilometers (about 900 miles) inland.
The simulations also indicate that the warming acceleration during such events is especially pronounced in autumn. The decade during which a rapid sea-ice loss event occurs could see autumn temperatures warm by as much as 5 degrees C (9 degrees F) along the Arctic coasts of Russia, Alaska, and Canada.

Lawrence and his colleagues then used the model to study the influence of accelerated warming on permafrost and found that in areas where permafrost is already at risk, such as central Alaska, a period of abrupt sea-ice loss could lead to rapid soil thaw. This situation, when summer thaw extends more deeply than the next winter's freeze, can lead to a talik, which is a layer of permanently unfrozen soil sandwiched between the seasonally frozen layer above and the perennially frozen layer below. A talik allows heat to build more quickly in the soil, hastening the long-term thaw of permafrost.

Arctic soils are believed to hold 30 percent or more of all the carbon stored in soils worldwide. Although researchers are uncertain what will happen to this carbon as soils warm and permafrost thaws, one possibility is that the thaw will initiate significant additional emissions of carbon dioxide or the more potent greenhouse gas, methane.

About a quarter of the Northern Hemisphere's land contains permafrost, defined as soil that remains below 0 degrees C (32 degrees F) for at least two years. Recent warming has degraded large sections of permafrost, with pockets of soil collapsing as the ice within it melts. The results include buckled highways, destabilized houses, and "drunken forests" of trees that lean at wild angles.

"An important unresolved question is how the delicate balance of life in the Arctic will respond to such a rapid warming," Lawrence says. "Will we see, for example, accelerated coastal erosion, or increased methane emissions, or faster shrub encroachment into tundra regions if sea ice continues to retreat rapidly?"

The study sheds light on how interconnected the Arctic system is, says NSIDC co-author Andrew Slater. "The loss of sea ice can trigger widespread changes that would be felt across the region."

The study was funded by the U.S. Department of Energy and by the National Science Foundation, NCAR's sponsor.

Title:
"Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss"
Authors:
David M. Lawrence, Robert A. Tomas, Marika M. Holland, and Clara
Deser: Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, Colorado, USA;

Andrew G. Slater: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA.

Citation:
Lawrence, D. M., A. G. Slater, R. A. Tomas, M. M. Holland, and C. Deser (2008), Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss, Geophys. Res. Lett., 35, L11506, doi:10.1029/2008GL033985.
Contact information for coauthors:
David Lawrence, NCAR Scientist, +1 (303) 497-1384, dlawren@ucar.edu

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation

nachricht Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>