Peat and forests save permafrost from meltingSeptember 14, 2007Permafrost may be buffered against the impacts of climate change by peat and vegetation present in the northern regions, according to a study by McMaster researchers. 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. McMaster University | |||||||||||||||||||||
|
Related Permafrost Current Events and Permafrost News Articles Dried 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. Bad sign for global warming: Thawing permafrost holds vast carbon pool 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. 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. More Permafrost Current Events and Permafrost News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||