Permafrost, which is any concentration of rock or soil that has been below the freezing point of water (0 C or 32 F) for over two years, is believed to be holding vast quantities of methane unable to come to the surface so long as the layer remains. As methane is a common gas that is both produced organically and from volcanic activities, there are many sources which could have supplied worrisome quantities on the verge of release. So in essence it isn’t really the thawing that produces the methane, but aids the release. And the release is the problem.
As a greenhouse gas, methane is considerably more dangerous than carbon dioxide once released to the atmosphere. The rapid breakdown through oxidation of the methane, which is composed of one carbon and four hydrogen atoms, in the atmosphere produces both carbon dioxide and water. The carbon dioxide creates the conditions for the greenhouse and the water absorbs more heat and adds to the melting process. This is why scientists fear an accelerated warming once methane stores begin to release.
Other sources of methane include landfills, decaying plants, coal mining, natural gas extraction, livestock, and deposits trapped within the Earth’s crust. One of the reasons there may be more methane beneath the ice layers is due to the conditions of the lower organisms that aid in the decay process. These microscopic creatures thrive in low oxygen environments and produce methane as a waste product. As the land where the permafrost is now wasn’t always covered in ice, there should be enough quantities of organic matter for the microbes to decay, which adds to the potential stores of methane.
It is speculated that when the ice melts in the initial holding area of methane it will begin the gradual release of the gas into the air. While the gas itself is harmless to humans, the fear from the oxidation is justified as any given quantity of methane in the air will do so by fifty percent every seven years. This means that a fixed quantity would breakdown rapidly and increase the greenhouse effects at a much faster rate, which would in turn thaw more permafrost and thus release more methane into the atmosphere to accelerate the process even further. It is the hope of the scientific community that the release involves only small quantities or there isn’t as much methane stored as speculated, but the potential for danger is there.