Lamb is one of Wales' most popular food exports
A group promoting Welsh meat has accused celebrities of "hijacking" the climate change debate at the expense of meat eaters and farmers.
Meat Promotion Wales chair Rees Roberts said campaigns like Meat Free Mondays portrayed meat eaters as people who did not care about the planet.
Sir Paul McCartney helped launch the campaign last month in an attempt to cut carbon emissions.
Mr Roberts spoke out on the first day of the Royal Welsh Show in Powys.
He said balance needed to be introduced into the debate because "extreme elements" were accusing farmers of "killing the planet".
But Mr Roberts said this was "utter nonsense".
Meat Free Mondays was launched to persuade people to help reduce carbon emissions by cutting out meat for a day week.
Mr Roberts said: "We've had celebrities calling for meat-free Mondays and even a town in Belgium trying to ban meat one day a week.
"The more extreme elements go further, accusing livestock farmers and meat eaters of killing the planet and heaping all the woes of climate change onto our shoulders.
"We need to introduce some balance into this debate because climate change concerns everyone.
"Hybu Cig Cymru (Meat Promotion Wales) is not different to any other responsible organisation in addressing the issue directly.
"We are working on a climate change roadmap, looking at the impact the beef and sheep supply chain has on climate change. We are investigating how to take positive steps to mitigate that impact without having an adverse effect on our businesses.
"This is a responsible approach. Our job is to feed the world, not destroy it."
Former Beatle Sir Paul is a vociferous supporter of animal rights, and played a key role at the launch of Meat Free Mondays, where he was joined by Yoko Ono and his daughter Stella McCartney.
Speaking beforehand, he said the campaign was already happening in Australia and the United States and could have a "hugely beneficial effect" on climate change.
On its website, Meat Free Mondays says to build a better world in the future people needed to make lifestyle changes now.
The campaign adds: "Not all the changes we have to make are easy, and not all the easy changes we can make are meaningful.
"But making just one day a week a meat-free day, really is the little thing that can make a big difference.
This year's Royal Welsh has seen a surge in livestock entries after fears they would plummet because of the recession.
There have been record entries for sheep, pigs and for several breeds of horses.
There is also good news for young farmers. The Welsh Assembly Government will launch a grant scheme later to encourage more people into farming.
Under the £2m scheme, younger farmers could receive a maximum of £15,000 to help establish their business.