More than half of British livestock production should be phased out on environmental grounds, according to a new report.
A cut in the number of animals reared in the UK should be matched be a substantial cut in consumption of meat and dairy products, added the report for the Food Climate Research Network.
This was the only way to control emissions of methane, nitrous oxide and carbon dioxide from cattle, claimed report author Tara Garnett, adding that organic farming produced more greenhouse gas than its conventional equivalent.
"We need to consider making significant reductions in our overall production of livestock products, while seeking to maximise the benefits that livestock can bring," Garnett said. "In short, we may need to eat fewer livestock products, and - if farming is to survive - pay more for them."
She said livestock should only be reared on marginal land that couldn't be used for any other form of agricultural production. Defra figures indicate such a move would cut grazing land by 55% and could reduce livestock numbers by even more. "Further research is needed to work out how much we should reduce consumption," Garnett claimed.
The report has provoked an angry response from the meat industry, which argued the livestock sector was part of the solution, not the problem.
"There are things the agricultural industry can do to mitigate emissions," said MLC chief executive, Richard Lowe. "Through manipulation of a cow's diet, for example, we can cut methane emissions 50%."
Britons' average consumption of protein from livestock products was 47g per day - considerably lower than countries including Spain, France and Germany, he added.
The Soil Association said the claims about organic production were wrong.