Title: Den arktiska permafrostens degradering och metangasutsläpp
Abstract:According to temperature data for the past 157 years, the global mean temperature is increas-ing with an accelerating rate in the end of the 20th century. Climate models that have been developed on re...According to temperature data for the past 157 years, the global mean temperature is increas-ing with an accelerating rate in the end of the 20th century. Climate models that have been developed on research centers around the world all show a warming trend the next coming 100 years. They also show that the increase in temperature will occur earlier and be more in-tense over the Arctic region.
In the northern hemisphere permafrost covers an area of 23 million km2. The main factor for the existence and degradation of permafrost is the atmospheric climate. However, regional factors such as precipitation, vegetation and snow cover also have some impact.
The Arctic soil contains about 14% of the global storage of soil carbon. When the permafrost thaws, the carbon is released as methane gas in an anaerobic decomposition. Since methane has a GWP (Global Warming Potential) of 23, i.e. is a 23 times stronger greenhouse gas than carbon dioxide, an increase in emission means a threat to the climate.
Methane also exists as methane hydrates, which are a frozen compounds consisting of a me-thane molecule surrounded by water molecules. These are formed at low temperatures and high pressure. The estimates of the size of the pool of methane hydrate differ. Older estimates say 8-700 Gt carbon while newer estimates say 5-195 Gt.
Research results show that around 100 Gt of carbon will be released from thawing permafrost before year 2100. The largest emissions is expected to come from Siberia (40 Gt) and Canada (48 Gt). As emissions from methane hydrates probably require more warming before it be-comes significant, the emissions from this source are more uncertain.Read More
Publication Year: 2010
Publication Date: 2010-01-01
Language: en
Type: article
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Cited By Count: 8
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