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Let's also not forget that methane, although a 'potent greenhouse gas', is not a big cause for concern in the atmosphere because water vapor will absorb electromagnetic radiation on it's spectrum of interest anyway.  This is kind of like the principle that if one is already behind an armor plate, putting up some bullet-proof glass in front of it has little effect.  See:  http://wattsupwiththat.com/2014/04/11/methane-the-irrelevant-greenhouse-gas/