GO vegan and save the planet, they say.
United States research shows that adopting a vegan diet for one year would reduce a person's carbon footprint by 0.8 tonnes of carbon dioxide emitted.
Dr Frank Mitloehner, an air quality specialist from the University of California Davis' Department of Animal Science, says a trans-Atlantic flight - per passenger - from the United States to Europe generates 1.6t of greenhouse gases.
"So in other words, it would take two years of being vegan to offset one single flight for one single person," Dr Mitloehner told delegates at the 2022 Australian Wagyu Association's annual conference in Melbourne yesterday.
He was speaking virtually on why the world needs to 'rethink' methane.
Other research determined if the entire population of the United States was to go meatless on Mondays, it would reduce the nation's carbon footprint by 0.3 per cent.
If the entire of the US population became vegan every day of the week - that is ate no animal-sourced foods whatsoever at any time - it would result in a carbon footprint reduction of 2.6pc of the US total.
The figures speak for themselves, Dr Mitloehner believes.
"I would argue the whole discussion around food choices and carbon emissions is largely a smokescreen," he said.
"It points at a source of greenhouse gas emissions but certainly not any of the major sources.
"Whether you personally eat one diet over another, the climate will not be changed in any major way."
Rather, one of the greatest impacts on the environment of food systems was wastage, he said.
A total of 40pc of food produced in the US is wasted - that's one out of three calories.
In all developing countries, that same percentage of food produced just never makes its way to the human digestive tract, he said.
"In the developed world, it is wasted at the consumer level - in kitchens and restaurants," Dr Mitloehner said.
"In third world countries, we speak of food losses rather than food waste because it's lost at the farmer level when farmers can't harvest in time, or transport, or preserve the food. But that number applies globally, either way.
"This is definitely the largest stone to turn around and look under if you were to be concerned about food systems and climate change."
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