Permafrost is thawing in northern Sweden
Permafrost is ground that is frozen year round at least two years in a row. North of the Arctic Circle permafrost is common due to the cold climate.
For several years, physical geographer Margareta Johansson at Lund University has studied lowland permafrost in peat mires surrounding Abisko. Permafrost is on the edge of its range there. Johansson states that permafrost is being affected by climate changes.
“At one of our sites, permafrost has completely disappeared from the greater part of the mire during the last decade,” she says.
In areas where permafrost is thawing the ground becomes unstable and can collapse. This can be a local and regional problem in areas with cities and infrastructure. Moreover, the thaw can cause increased emissions of the greenhouse gases carbon dioxide and methane from the ground. Roughly 25 percent of all land surface in the northern hemisphere are underlain by permafrost.
The thawing of permafrost that occurs today is likely to continue, in Margareta Johansson's view. She regards it as probable that there will be no permafrost in lowland areas around Abisko in 50 years.
“With the present climate it is likely that the changes seen in permafrost in the Abisko area will also occur in other areas, and my study can therefore provide a basis for studies in other geographic areas that are next in line,” she says.
Margareta Johansson's research shows that the permafrost in the Abisko area is thawing both from above and from below. From above it is thawing primarily because the summers have become warmer and because the snow cover has become thicker in winter. A thicker snow layer acts as an insulating blanket, which means that the ground does not get as cold as it would under a thinner layer of snow.
From below the permafrost is thawing probably as a result of greater mobility in the groundwater. Margareta Johansson explains that the annual precipitation of both rain and snow has increased dramatically during the last decade. More rain and more melted snow create more movement down in the groundwater, which thaws the permafrost. Between 1997 and 2007 a total of 362 millimeters of precipitation fell annually in Abisko, which is a 20-percent increase compared to the mean annual precipitation for the years 1961 and 1990.
The dissertation will be presented and defended at Lund University
on February 26, 2009.
For more information, please contact Margareta Johansson,
phone: +46-46 222 44 80 or margareta.johansson@nateko.lu.se.
Pressofficer Lena Björk Blixt,Lena.Bjork_Blixt@kanslin.lu.se
or +46-46 222 71 86
Media Contact
More Information:
http://www.vr.seAll latest news from the category: Earth Sciences
Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.
Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.
Newest articles
“Nanostitches” enable lighter and tougher composite materials
In research that may lead to next-generation airplanes and spacecraft, MIT engineers used carbon nanotubes to prevent cracking in multilayered composites. To save on fuel and reduce aircraft emissions, engineers…
Trash to treasure
Researchers turn metal waste into catalyst for hydrogen. Scientists have found a way to transform metal waste into a highly efficient catalyst to make hydrogen from water, a discovery that…
Real-time detection of infectious disease viruses
… by searching for molecular fingerprinting. A research team consisting of Professor Kyoung-Duck Park and Taeyoung Moon and Huitae Joo, PhD candidates, from the Department of Physics at Pohang University…