Permafrost is frozen soil that remains at or below 0 oC for at least two consecutive years. Currently, it covers more than 30 per cent of the Earth’s surface and about 42 per cent (four-million square kilometres) of Canada’s land mass.
The study was published recently in Geophysical Research Letters.
“There is no doubt that northern regions are warming and permafrost is melting as shown by numerous observations and modeling studies,” says Altaf Arain, co-author of the study and associate professor in the School of Geography and Earth Sciences. “However, there is large uncertainty about the rate and magnitude of permafrost degradation and thaw depth.”
Previous studies using the U.S. National Center for Atmospheric Research Community Climate Model suggest that global warming is rapidly melting permafrost in the North regions. According to those studies, only a million square kilometres of the currently estimated 10.5-million square kilometres of permafrost would remain by the end of this century.
However, Arain says these studies failed to consider the impact of peat and vegetation cover.
“A layer of peat above the permafrost acts as insulation by trapping air pockets, which reduce heat transfer and helps permafrost retention,” he says. “Vegetation can also help slow the rate at which permafrost melts because it shades the ground.
Arain and co-author Dr. Ming-ko (Hok) Woo, professor emeritus at the School of Geography & Earth Sciences, used the NCAR Community Land Model (CLM3) with several modifications and historical climate records. Their results indicated that although permafrost degradation was predicted over the 2000 to 2100 period, areas with mineral-based soil and no vegetation were most affected.
Forest cover provided more protection than shrubs or bare ground, and thick layers of peat were such effective insulators that permafrost showed only minimal decline even by 2100. On the other hand, Arain adds, disturbance of the ground cover on a local scale or fires in the boreal forest and tundra can lead to accelerated permafrost thaw. Forest fires in permafrost regions, which may become more prevalent in the future, can reduce surface organic layer, and this can affect ground thaw on both local and regional scales. Preservation of peat layer and forests may help in maintaining permafrost in northern regions.
Jane Christmas | EurekAlert!
NASA examines newly formed Tropical Depression 3W in 3-D
26.04.2017 | NASA/Goddard Space Flight Center
Early organic carbon got deep burial in mantle
25.04.2017 | Rice University
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...
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...
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...
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...
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...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy