Moves to shrink livestock farming through things like Meatless Mondays and lab-grown meat aren't going to save the planet from climate change, says Brisbane-based meat scientist, Professor Louwrens Hoffman.
He says if every American shunned meat on Mondays they would reduce greenhouse gas (GHG) emissions by only 0.5 per cent. If they stopped eating meat altogether they would cut GHGs by just 2.6pc.
Researchers at England's Oxford University also had recently warned large-scale production of lab-grown beef using cell culture could potentially have a bigger carbon footprint than cattle.
This so-called "labriculture" produced carbon dioxide which persisted in the atmosphere for millennia while cattle emitted methane which remained for about 12 years.
The push for Meatless Mondays in the US was given a boost when New York Mayor, Bill de Blasio, announced the city's 1800 schools would offer only vegetarian breakfasts and lunches on Mondays.
In a science seminar which was live streamed, Professor Hoffman discussed the challenges of providing enough protein to feed an estimated 9.6 billion people by 2050 while tackling climate change and protecting the environment.
He is based at the Queensland Alliance for Agriculture and Food Innovation (QAAFI), a research institute of the University of Queensland.
Livestock farming has been under attack for decades for allegedly making too big a contribution to the rise in GHG emissions. Professor Hoffman said early estimates of agriculture's GHG emissions had been exaggerated.
Back in 2009 the Worldwatch Institute asserted 51pc GHG emissions were generated from rearing and processing livestock. In 2006 the UN Food and Agriculture Organisation said 18pc of the world's GHGs were due to livestock which Professor Hoffman said had recently been pruned back to 14.5pc.
Increasing demand for action on climate change was being driven by the new generation in the industrialised world who were also concerned about animal welfare, sustainability of the environment and "healthy" diets.
They were seeking answers to their concerns and wanted to be part of the solution. They were also driving interest in meat alternatives such as plant-based products and food made from insects.
Professor Hoffman said plant-based "meat-like" products were here to stay while insects as a source of protein would increase.
Extensive ruminant production systems were here to stay because much of the land used for agriculture was suitable only for grazing. Around 51pc of the Australian landmass was used for farming but grazing was the only option on 87pc of it.
But he wondered whether intensive animal production would become a thing of the past because animals such as poultry were consuming expensive feeds which could be eaten directly by humans.