Saturday, February 6, 2016

Wait, what about human flatulence?


By now, some of you may be wondering why we’ve been focusing so much on cow gas emissions. After all, there are more humans than cows, should we be concerned about our own bodily gas emissions? Well, I for one thought this was a fascinating question and so I went to seek out an answer for myself and for all of you.

Turns out, there are some fundamental differences in the digestion system of cows and humans (probably not too unexpected). Cows are what we call ruminant livestock. Ruminants have four stomachs (sort of) and store their food in the first chamber of their stomach before regurgitating it. This regurgitated food is called “cud,” which is then re-chewed to help with the digestion process. Actually, the majority of methane cows produce comes from their mouths rather than flatulence, because of this unique digestive process. So, as we can see, not all mammals are created equal when it comes to gas emissions.

So just how do gases produced by the human body compare to gases produced by ruminants? For those of you who are less then passionate about math, I will spare you the calculations (and state my assumptions below). According to my calculations, all the cows around the world would produce about 2.75 x 108 kg per day of methane. According to some rough calculations by Brian Farley, a postdoc at UC Berkeley, the world’s human population would produce about 7.3 x 104 kg of methane per day. To be clear, that is saying that the amount of methane produced by cows is nearly 10,000 times greater than all of humanity, reason being that they are ruminant livestock.

For a clear understanding of this fascinating digestive process, you can watch this short video.


To read a little more about methane produced by ruminants, check out this link. http://www.ghgonline.org/methaneruminants.htm

Learn more at http://methaneeducation.weebly.com

Sources:

Assumptions:
Methane density = 0.656kg/m3
There are 1.4 billion cows worldwide
1 cow produces 300 liters of methane a day (approximation from above source)


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