Robert Howarth, an ecologist and evolutionary biologist, and Anthony Ingraffea, a civil and environmental engineer, reported that fracked wells leak 40 to 60 percent more methane than conventional natural gas wells. When water with its chemical load is forced down a well to break the shale, it flows back up and is stored in large ponds or tanks. But volumes of methane also flow back up the well at the same time and are released into the atmosphere before they can be captured for use. This giant belch of "fugitive methane" can be seen in infrared videos taken at well sites.Flaring natural gas can't help either.
Molecule for molecule, methane traps 20 to 25 times more heat in the atmosphere than does carbon dioxide. The effect dissipates faster, however: airborne methane remains in the atmosphere for about 12 years before being scrubbed out by ongoing chemical reactions, whereas CO2 lasts 30 to 95 years. Nevertheless, recent data from the two Cornell scientists and others indicate that within the next 20 years, methane will contribute 44 percent of the greenhouse gas load produced by the U.S. Of that portion, 17 percent will come from all natural gas operations.
Currently, pipeline leaks are the main culprit, but fracking is a quickly growing contributor. Ingraffea pointed out that although 25,000 high-volume shale-gas wells are already operating in the U.S., hundreds of thousands are scheduled to go into operation within 20 years, and millions will be operating worldwide, significantly expanding emissions and keeping atmospheric methane levels high despite the 12-year dissipation time.
Saturday, January 21, 2012
Another Environmental Impact Of Fracking
Scientific American, via nc links:
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