Sunday, September 07, 2008


Cattle are not the cause of methane increases, according to research by the Food and Agriculture Organisation, a United Nations agency. “Since 1999 atmospheric methane concentrations have levelled off while the world population of ruminants has increased at an accelerated rate,” it reports at
“The role of ruminants in greenhouse gases may be less significant than originally thought, with other sources and sinks playing a larger role in global methane accounting,” says the FAO.
In 2003 the National Oceanic and Atmospheric Administration reported that the concentration of the methane in the atmosphere was leveling off at the 1999 level. The Intergovernmental Panel on Climate Change acknowledged this in 2007, with “emissions being equivalent to removals.”
This report is a dramatic reversal of the FAO’s position in its 2006 paper called “Livestock’s Long Shadow” in which it blamed cattle for most of the greenhouse and environmental ills. This was leapt upon by vegan, vegetarian and religious groups which urged consumers to avoid meat or reduce their intake to save the planet.
Professor Aslam Khalil, at the Portland State University, in an analysis of more than 20 years of atmospheric sampling, concluded that “global emissions and the lifetime of methane in the atmosphere have been constant, so the buildup of methane in the atmosphere has been slowing for as long”. Since 1999, there has been a non significant atmospheric increase of 0.3 ppb methane/year. This contrasts with the 10.8 ppb/year for the previous time period of 1979 to 1999. “Seeing that the total source has remained constant for at least the last two decades, it is questionable whether human activities can cause methane concentrations to increase greatly in the future.”

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