Methane’s greenhouse contribution is second only to that of carbon dioxide. Even though it is
present in far lower concentrations than carbon dioxide, methane is about 22 times more
effective at trapping heat than an equal amount of carbon dioxide. Decomposition of landfill
wastes, coal mining, digestive gases from domestic animals, and the burning of fossil fuels all
release methane gases into the atmosphere.
Atmospheric concentrations of methane have
increased 246 percent from an estimated preindustrial level of 700 ppb to a 1998 level of 1,720
ppb (ARM 2000, 1). There are enormous quantities of methane gases trapped in icelike
structures called clathrates both in the frozen arctic tundra and in the icy depths of the deep
These clathrates contain 3,000 times more methane than the atmosphere. If much of the
arctic’s permafrost melts and releases its trapped methane into the atmosphere, this alone will be
enough to cause global climate changes of a proportion that will dwarf current projections.
Unfortunately, some scientists believe that just a few degrees warming of the deep oceans could
be enough to release the deep-ocean clathrates in a catastrophic “methane burp” with the
potential to seriously threaten life on Earth. There is strong geologic evidence that this has
already happened twice in the history of planet Earth, causing rapid warming and massive
extinctions and die-off, disrupting the climate for more than 100,000 years (Atcheson 2004).