EGEE 101
Energy and the Environment

Methane

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US Methane emissions by source
Surprisingly leaky pipes and the petroleum industry are not the biggest contributors; rather livestock and landfills (your junk) contribute >50% of the methane emissions! (1990 to 2014)
Credit: EPA

The CO2 is not the only gas that is contributing to the increased concentration in the atmosphere. Methane (CH4) is also being released into the atmosphere and as it is a more efficient greenhouse gas (one CH4 molecule is roughly equivalent to twenty-one CO2 molecules). So if we can plug the leaks that would help mitigate climate change (possibly).

Recall that coal mines can be a source of methane leaks. Two gigantic coal mines in Russia, for example, are responsible for much of that country's methane release. Capturing the methane and using it also helps lower greenhouse gas emissions (if it is replacing coal) because it has a higher efficiency (combusts at a higher temperature).

Animals, particularly cows, are another source of methane! I forget how many stomachs a cow has, my nephew (8-year-old) says 4! While processing the food they eat, the average cow will emit 280 liters of methane gas a day or about 119 pounds CH4/head/year (Johnson and. Ward, 1996). There is not much we can do to capture this short of a rather vulgar bovine attachment. However, if we were to be vegetarians, you can feel better about your personal contribution to the increased concentration of greenhouse gasses. But if you also eat a lot of rice (I love rice, being English it is our national food—with a good curry of course) then you help to produce a significant amount of methane. The rice paddies require fertilization, and being a stagnant water supply is low in oxygen, and so methane is produced.

 left, landfill, right, a rice field
Left: Landfill sites contribute approximately 18% of the anthropogenic methane.
Right: Reminiscent of all the Vietnam war movies, this rice paddy requires enough water to flood the field for rice to grow.
Credit: EPA

Bottom line: Teriyaki Beef with rice (the special at Spats last week — Splendid) is not the most environmentally friendly dish you can have! I should feel more guilty about driving the car to the office, that trip had the greater contribution to my greenhouse gas emissions!