Among the trace gas villains implicated in a warming world is methane. Are we Gaian liberators of this satanic gas? Not compared to the whitetail deer which is 240 times more flatulent than women (men as well) on a per kilogram of body weight basis. Nor to the warthog which is a modest 120 times more flatulent per kilogram of body weight than the average of us.
Flatulence is a matter of health, food, and choice. Yes, with some willpower, you can hold tight. Thirty to 50% of healthy people produce methane and release it as flatus gas. The rest of us hold it in, reabsorbing it into our bloodstream and letting our lungs do the release in a socially acceptable way. Make your own assessment as to your group membership.
For the by-the-lungs crowd, exhaled methane production averages 1.5 ml/min. Humanity, as a collective, breathes a sigh of relief totaling 0.1 Tg/year. The back-door crowd runs their engines with a flatus gas output in the range of 2 to 8 percent methane rich. Collectively, man produces 0.2 Tg/yr by this method for a front-door, back-door total of 0.3 Tg/year. (One Tg/yr = 10 to the 12th-power grams.)
Global methane production is somewhere between 300 and 500 Tg/yr. We are not Gaian Villains driven by enteritic fermentation after all. We are wimps. The global warming, at least methane's part, rests on the hooves of others. So you can breathe more easily.
Data for this article comes from researchers who warned us of Nuclear Winter (now Nuclear Autumn) see Tellus (38B) 1986. Those interested in what microbes can really do should read J. E. Hobbie and J. M. Melillo in Current Perspectives in Microbial Ecology, ed. Kluge and Reddy, 1984.