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Name: Beth
Status: other
Grade: other
Location: KY
Date: August 2008

On NPR they were talking about the dangerous amounts of methane that cows produce. How does the human output of methane compare?

Beth, As you probably know already, methane is a greenhouse gas. Other gases include carbon dioxide, nitrous oxide and halogen (mostly fluorine and chlorine) compounds. Today the portions of each are: CO2 = 85%, methane = 8%, nitrous oxide = 5+%, and halogen compounds = 2% of emitted green house gases.

Most of the methane comes from one of three sources: manure = 7.5%, animal belching/burping = 22.7% and landfills = 69.8%. Human-generated methane apparently does not compare.

Some large feed-lot operators are installing methane converters. These processors remove the methane from the manure and burn the methane to drive electric power generators for the feed-lot. Similarly municipalities that "host" landfills, collect the methane and also burn it to generate electricity.

Cows naturally produce methane as they digest the hay and other plants in their diet. The cows have bacteria in their stomachs that produce the methane as the cellulose in the plants gets broken down into chemicals that the cows can take into their cells to live and grow. About 3/4 of the methane produce gets belched/burped into the atmosphere. The rest leaves in manure.

Somewhere some bright Ph.D candidates are trying to find alternative bacteria that will allow the cows to digest the hay, yet cut down or eliminate the methane by-products.

And keep listening to NPR.


Warren Young

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