A plant-based diet is 'the only way' to feed the planet's growing population, an environmental activist has said.
George Monbiot said livestock farming ranks with the fossil fuel industry as one of the two most destructive industries on Earth – but entirely different standards are being applied to each.
But he said entirely different standards are being applied to the farming than fossil fuels.
During a debate on Newstalk Breakfast, Mr Monbiot said farming emissions far outweigh any positive environmental impact.
"There has not been a cattle farm anywhere in the world which has been established as carbon neutral or carbon negative," he said.
"The process emissions - the methane from the cattle, nitrous oxide from the cattle's dung plus the farm's operations - massively outweigh any greenhouse gasses stored in the soil.
"Carbon saturates after a few years, you can't keep adding to it but the emissions from the farm continue".
'A natural process'
Irish Creamery Milk Suppliers Association President Denis Drennan said we need to have a 'mature' discussion.
"If you get into your car and drive home you burn petrol or diesel, you turn on your heating [which] is gas or oil that has been in the ground for thousands of years," he said.
"You burn that carbon, you release brand new carbon into the atmosphere.
"If I look at my cows grazing this morning they emit carbon dioxide through respiration, the same as you and I do.
"They also emit a small amount of methane which is a natural process but we have to look [at] where did that carbon dioxide and methane come from?"
Cows grazing, 28-8-18. Image: Malcolm Buckland / AlamyMr Drennan said the process is part of a natural cycle.
"Through photosynthesis, grass turns carbon dioxide from the air into a carbohydrate in the form of grass, cows eat the grass [it] goes back into the atmosphere and comes back down," he said.
"The farming community do not get credit for the CO2 that's sequestered by the grass as it grows.
"Every tonne of grass that my cow eats... is sequestering about 3.6 tonnes of carbon dioxide".
'Apples and oranges'
Mr Drennan said comparing farming to the burning of fossil fuels is 'completely unfair'.
There's no positive to burning fossil fuels; it's fresh carbon you're releasing into the atmosphere," he said.
"With the grass-growing cycle at least there's a debit and a credit, so comparing the two is like apples and oranges".
Mr Monbiot said any offset offered is simply not enough.
"The debt massively outweighs the credit - you're producing on a cattle farm far more greenhouse gasses," he said.
"Part of the reason for that is you're turning carbon into methane which has a massively greater greenhouse gas impact than carbon dioxide does.
"Sure there's cycling going on but the cycling doesn't in any way counteract the overall climate impact of the operation".
'We need food'
Mr Drennan said criticism of farming is forgetting one vital element.
"We need food to live," he said.
"Wild natural forests when they grow up and the tree falls over and dies... whatever carbon it has sequestered in its lifetime if it's left there to rot will release all that carbon back into the atmosphere.
"So there's a lot of holes in your argument.
"There's over eight billion people on the planet and growing rapidly and we have to find a source of nutritious food for those people."
Mr Drennan said "it's an easy one to pick on the farmer".
'Greatest threats'
Mr Monbiot acknowledged that fossil fuels need to be moved away from in general.
"I'm not saying that just getting out of livestock is going to solve the problem by itself," he said.
"Of course we urgently need to be getting out of fossil fuels as well but the two greatest threats to the living world are fossil fuels and livestock farming".
Mr Monbiot said livestock farming also requires more land "than anything else that human beings do.
"Precisely because we have such a high human population we cannot afford to keep trying to feed people on livestock products.
"There's simply no good way of feeding everyone on animal products.
"We do need to feed people but that means, unfortunately, for people who like their steaks, the responsible thing is to switch to a plant-based diet.
"In doing so you reduce your land footprint by three-quarters, you reduce your greenhouse gas footprint from food by about three-quarters.
"It's the only way now we can accommodate the numbers of people on this planet without busting through planetary boundaries".
Mr Monbiot admitted it is an "uncomfortable truth".
