Friday, 26 September 2008


Methane is a colourless, odourless gas with a wide distribution in nature, a product of decomposition of vegetable and animal matter. Anaerobic decomposition under water produces methane known as 'marsh gas' whilst to miners it is known as 'firedamp'. Ruminants such as cattle also produce large quantities as a by-product of digestion. Humans and other animals are
also producers.

'Natural Gas' pockets from beneath the North Sea has been supplying British homes and industry for decades and in the past decade methane has provided 20% of worldwide energy consumption, over 30% in the United States.

Like all other fuels, when burnt carbon dioxide is a combustion product but when released as methane it is a greenhouse gas over 20 times worse that carbon dioxide.

Most of the methane pockets that are exploited for fuel are trapped beneath rock but much of the ancient methane has been trapped within and beneath the permafrost of the polar regions but global warming is already beginning to cause release of this massive store. The photo to the right shows a demonstration of escaping methane from an Arctic lake.

Orjan Gustoffsson of Stockholm University recently stated: "The conventional thought has been that the permafrost 'lid' on the sub-sea sediments on the Siberian shelf should cap and hold the massive reservoirs of shallow methane deposits in place. "

(Credit: Photo by Sergey Zimov)
"The growing evidence for release of methane in this inaccessible region may suggest that the permafrost lid is starting to get perforated and
thus leak methane."

Dr. William Dillon
(U.S. Geological Survey) writes " Methane trapped in marine sediments as a hydrate represents such an immense carbon reservoir that it must be considered a dominant factor in estimating unconventional energy resources; the role of methane as a 'greenhouse' gas also must be carefully assessed.

He goes on to write "Hydrates store immense amounts of methane, with major implications for energy resources and climate, but the natural controls on hydrates and their impacts on the environment are very poorly understood.

"Gas hydrates occur abundantly in nature, both in Arctic regions and in marine sediments. Gas hydrate is a crystalline solid consisting of gas molecules, usually methane, each surrounded by a cage of water molecules. It looks very much like water ice. Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose sediments in a surface layer several hundred meters thick."

The worldwide amounts of carbon bound in gas hydrates is conservatively estimated to total twice the amount of carbon to be found in all known fossil fuels on Earth.

Though it may be feasible to harvest some of the sediment hydrates it is not feasible to collect and safely store any significant proportion of shallow permafrost methane stocks. So the best that mankind can do is to reduce our contributions to the warming process whilst preparing as best we can for the inevitable consequences.

Responsible cleaning professionals are moving to more eco-friendly cleaning products

1 comment:

Brandon McBride said...

Methane sounds dangerous. You see it in movies like The Rundown, but it's always downplayed.