Livestock's Long Shadow calculated meat-related emissions from field to abattoir
UN specialists are to look again at the contribution of meat production to climate change, after claims that an earlier report exaggerated the link.
A 2006 report concluded meat production was responsible for 18% of greenhouse gas emissions - more than transport.
The report has been cited by people campaigning for a more vegetable-based diet, including Sir Paul McCartney.
But a new analysis, presented at a major US science meeting, says the transport comparison was flawed.
Sir Paul was one of the figures launching a campaign late last year centred on the slogan "Less meat = less heat".
But curbing meat production and consumption would be less beneficial for the climate than has been claimed, said Frank Mitloehner from the University of California at Davis (UCD).
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Smarter animal farming, not less farming, will equal less heat," he told delegates to the American Chemical Society (ACS) meeting in San Francisco.
"Producing less meat and milk will only mean more hunger in poor countries."
