Sir Paul McCartney has shrugged off attacks on his "Meat-Free Monday" campaign and called for a global effort to change eating habits and help save the planet from global warming.
He took the meat-free message to Brussels and told a European Parliament conference that it was possible to adapt - and that one day's less meat-eating a week could have a major impact on overall effort to cut CO2 emissions.
Speaking in the Parliament chamber to MEPs, and climate change and food experts, he said: "This isn't just me, a vegetarian, banging on: it was a United Nations report, Livestock's Long Shadow, that got me interested.
"Since then there been many more studies and I personally think there's an urgent need to do something: the livestock industry produces more greenhouse gases than all forms of transport - cars, plane, trucking - put together.
"We thought cars were the villain of the piece but it appears livestock produces more, not to mention deforestation for grazing, or for growing animal feed - one third of cereal crops are grown for animals."
Sir Paul said gases released from cows "belching" methane would be "degrading" the climate for decades to come: "People are confused about what they can do - they can try one meat-free day a week. It's kind of interesting once you get into it."
Sir Paul read out a statement from US climate change guru Al Gore, which said: "Meatless Mondays is a responsible and welcome component to a strategy for reducing global pollution."
Dr Rajendra Pachauri, Chairman of the Intergovernmental Panel on Climate Change, a fellow speaker at the "Global Warming and Food Policy: Less Meat = Less Heat" conference, backed Sir Paul, insisting: "Cutting meat down to five or six days a week will certainly make a difference."
But Irish MEP Mairead McGuinness told the event: "We were told (at school) to give up meat on Friday to save our soul, and now we are being told to give up meat on Monday to save our planet and, frankly, neither will work."
"I believe agriculture and livestock are part of the problem, but they are not the problem. European agriculture has made huge efforts with success to reduce emissions and research is pointing us in the direction of further improvements."