It’s the Methane, S***** (Intellectually Challenged)
by Bob Brown on March 29, 2012 at 12:01 pm |
“Natural gas” is mostly methane (CH4), a relatively potent greenhouse gas. The concentration of methane in the Earth’s atmosphere is expressed as a mole fraction, nmol/mol (parts per billion, ppb). It was about 700 ppb in 1750; in 1998, it was 1745; it stayed flat for awhile but then began rising, to over 1850 ppb by 2010.
Methane is being released into the atmosphere by natural processes, it is a strong positive feedback to GW as the protective ice cover retreats and methane is released from permafrost and methane clathrates in the ocean.
But it is also being released by commercial fuel production at an increasing rate in the name of reducing CO2 release (from coal burning e.g.). In the production process and finally in combustion it combines with oxygen to produce water and CO2. Methane stays in the atmosphere about a decade with thirty times the GHG effect of CO2. It then converts to CO2 which stays around for centuries. One way of “controlling” methane release is to burn it off, producing the less potent CO2.
Recently our commercial production of shale gas has doubled by using the process of hydraulic fracturing the shale rock to produce shale gas. In the process, the leakage of the methane to the atmosphere is about 10%. So we are increasing methane release (along with toxic metals, hydrocarbons and radioactive material in the shale) from this gas production. Again we are plunging ahead without having carefully studied the environmental repercussions.
Once the climate modelers get methane feedback into their models, with the new sources of methane, expect to see new, more dire predictions of global warming. Already predictions from those who study the processes say there is a possibility of catastrophic warming if the net GH gases get above a “tipping point” (which some say has already been passed, some say in 15-35 years).
Of course we can all hope that the scientists are all wrong.
http://blog.seattlepi.com/robertbrown/2012/03/29/it’s-the-methane-s-intellectually-challenged/
