WASHINGTON – One author of the 2006 United Nations report claiming meat production is responsible for 18% of global greenhouse gas emissions is acknowledging the comparison is flawed in light of recent research by an American scientist, the BBC said.

Dr. Frank Mitloehner from the University of California at Davis, author of the published study, “Clearing the Air: Livestock’s Contribution to Climate Change,” said it is simply not scientifically accurate to blame livestock for climate change, the American Meat Institute points out.

Mr. Mitloehner traces much of the public confusion to the 2006 report, “Livestock's Long Shadow,” published by the United Nations’ Food and Agriculture Organization (F.A.O.), which he said overstates the role livestock play in greenhouse gas emissions.

“This lopsided ‘analysis’ is a classical apples-and-oranges analogy that truly confused the issue,” Mr. Mitloehner said. He presented his findings at this week’s American Chemical Society conference in California, which was reported on by A.M.I.

Pierre Gerber, a policy officer with FAO, told the BBC he accepted Mr. Mitloehner’s criticism. “I must say honestly that he has a point – we factored in everything for meat emissions, and we didn't do the same thing with transport,” he added.

Attempts to apply these global numbers to the U.S. are misleading because the vast majority of global greenhouse gas emissions attributed to livestock production result from deforestation and converting rain forests and other lands to grow crops or pasture, A.M.I. has long contended. Such changes do not occur in the U.S., which has seen an increase in the total acreage of forested land over the last several decades even while total agricultural production has increased.

In 2007, only 2.8% of U.S. greenhouse emissions came from animal agriculture, according to the Environmental Protection Agency (E.P.A.). This number has remained nearly constant since 1990, which is impressive considering U.S. increases in meat production of almost 50% over the same time period.

“The fact that greenhouse emissions have remained nearly constant while industry production has increased shows that U.S. livestock and meat producers have taken responsible steps to protect the environment, such as improving feed efficiency, implementing better manure management strategies and using cropland more effectively,” said J. Patrick Boyle, A.M.I. president and chief executive officer. “We’ve accomplished this feat all the while providing the most abundant, safe, diverse and affordable meat supply in the world.

“A.M.I. looks forward to F.A.O.’s completion of a more comprehensive analysis of emissions from global food production at the end of this year,” Mr. Boyle concluded.