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 Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Predicting unpredictability: Information theory offers new way to read ice cores

07.12.2016 | Earth Sciences

Sea ice hit record lows in November

07.12.2016 | Earth Sciences

New material could lead to erasable and rewriteable optical chips

07.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>