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 Oxford University in England also had recently warned large-scale production of lab-grown beef using cell culture techniques 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 United States was given a boost recently when New York Mayor, Bill de Blasio, announced the city's 1800 schools would soon offer only vegetarian breakfasts and lunches on Mondays.
The Meatless Mondays initiative was launched in the US in 2003 and has spread to 23 countries.
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 and agriculture generally have 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.
He said increasing demands for action on climate change were being driven by the new generation in the industrialised world (the post millenniums) who were also concerned about issues like animal welfare, sustainability of the environment and "healthy" diets.
The young generation (25pc of the population) were seeking answers to their concerns and wanted to be part of the solution. They were also driving the interest in livestock meat alternatives such as plant-based products and food made from insects.
Big business was investing heavily in meat alternatives because trendy consumers were willing to pay higher prices for them.
Professor Hoffman said plant-based "meat-like" products were here to stay while the use of 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 agriculture but grazing was the only option on 87pc of it.
But he wondered whether intensive animal production systems would become a thing of the past because animals such as poultry were consuming expensive feeds which could be eaten directly by humans.