Human Methane Output
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?
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
And keep listening to NPR.
Click here to return to the General Topics Archives
Update: June 2012