Permafrost Releasing Methane
World's Largest Source of Greenhouse Gases
Click For Large Map
Any soil or rock that has remained below 0° C (32° F) continuously for two or more years is known as Permafrost. 18 percent of the exposed land surface in the Northern Hemisphere has permafrost below. Permafrost can contain over 30 percent ice. The overlying ground surface layer that freezes every winter and thaws every summer is called the “active layer” or “seasonal frost” layer. Seasonal frozen ground covers as much as 55 percent and is made up largely of vegetation which becomes much like wet peat moss when thawed.
As permafrost melts, that plant matter within starts to rot, releasing huge quantities of methane gas which is 21 times more damaging to the atmosphere that carbon dioxide. Scientists estimate the permafrost worldwide holds 500 billion tonnes of carbon in the form of plant matter which, as it decays, releases methane. The deposits of organic matter in these soils are so gigantic that they dwarf all the known global oil reserves.
In the arctic there are large mines, oilfields, pipelines, airstrips and a nuclear power station in Russia. All this infrastructure is built on permafrost. Many of these structures were engineered to the stability of the permafrost beneath. As the permafrost thaws, the ground shifts leaving these structures in threat of collapse. A very possible spill of hazardous chemicals into the environment and may occur and become a threat to the ecosystem and human lives.
Permafrost Climate Change Studies
Current General Circulation Models predict substantial warming in the high latitudes of North America as a consequence of increased atmospheric concentrations of anthropogenic greenhouse gases. Historical temperature trends show a warming of nearly 2°C during the last century in the western Canadian Arctic. In addition, extreme conditions such as the El Niño year of 1998 resulted in mean annual temperatures 5°C warmer than the average conditions. These data indicate that future warming in the western Canadian Arctic may be greater than other parts of Canada. This warming is expected to have a significant impact on the stability of permafrost. Therefore, it is essential to develop a sound understanding of the impact of climate change in permafrost regions and to provide this knowledge to decision-makers considering adaptations to climate change in the North.
Gas hydrates S.R. Dallimore, J.F. Wright, F.M. Nixon 
Gas hydrates occurring beneath the continental shelves of the world and associated with deep permafrost represent the single largest known source of mobile carbon. Methane hydrate, thought to be the most common form of gas hydrate, is only stable under specific conditions of low temperature and moderate pressures. When these conditions are changed by processes such as climate warming or fluctuations in sea level, there is a significant risk of an increased flux of methane into the atmosphere. Research in the Mackenzie Delta/Beaufort Sea and Arctic Islands is focussed on assessing the distribution of methane hydrate and its sensitivity to climate warming.
- Login or register to post comments
- Printer-friendly version