Methane
{{#badges: Climate change |CoalSwarm | WaterEnergy}} Methane (CH4) is a potent greenhouse gas with a high global warming potential 72 times that of carbon dioxide (averaged over 20 years) or 25 times that of carbon dioxide (averaged over 100 years), according to the Intergovernmental Panel on Climate Change (IPCC)'s Third Assessment Report. Methane in the atmosphere is eventually oxidized, producing carbon dioxide and water. This breakdown accounts for the decline in the global warming potential of methane over longer periods of time.[1] The global warming potential of methane was estimated at 21 times that of carbon dioxide, averaged over 100 years, in the IPCC Second Assessment Report, and the 21 figure is currently used for regulatory purposes in the United States.[2]
In September 2008, The Independent newspaper reported how preliminary scientific findings suggested that massive deposits of sub-sea methane were bubbling to the surface as the Arctic region becomes warmer and its ice retreats. This methane time-bomb is seen as extremely worrying, because it could be a positive feedback mechanism, where the more the Arctic melts the more methane is released, which could put us on the path to runaway global warming.[3]
Coal mining accounts for about 10 percent of US releases of methane.[4] It is the fourth largest source of methane, following landfills, natural gas systems, and enteric fermentation.[4]
Methane released by coal mining includes:[5]
- Underground Mining: In the United States, methane from underground mining operations is typically vented. In some other countries it is also flared.
- Surface Mining: During surface mining, methane is released directly to the atmosphere.
- Post-Mining Activities: Some methane remains in the coal after mining and is released during subsequent processing and transportation.
- Abandoned Mines: Methane emissions from abandoned mines are not quantified and included in U.S. inventory estimates, but may be significant.
Resources
References
- ↑ Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)"Climate Change 2007: Working Group I: The Physical Science Basis: 2.10.2 Direct Global Warming Potentials", IPCC Fourth Assessment Report: Climate Change 2007, Cambridge University Press, 2007.
- ↑ "Methane," U.S. Environmental Protection Agency information page, accessed July 2010
- ↑ Steve Connor, "Exclusive: The methane time bomb", The Independent, September 23, 2008
- ↑ 4.0 4.1 U.S. Environmental Protection Agency ,"Methane: sources and emissions," U.S. Environmental Protection Agency website, October 20th, 2006.
- ↑ "Coal Mine Methane Recovery," Power Partners Resource Guide, accessed May 2008
Related SourceWatch Articles
- Fracking
- Marcellus Shale
- Methane released by coal mining
- The methane time-bomb
- Natural gas as an alternative to coal
- Natural gas transmission leakage rates
- Powder River Basin
External links
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