Can eating beef save the planet?

^{By Raymond Gill}

In an article published in The Spectator Australia, geologist and climate sceptic Emeritus Professor Ian Plimer argues that it is “absolute nonsense to claim that beef farming accelerates hypothetical global warming”, and that “if the popular mantra is used, we are saving the planet by eating beef”.

RMIT FactLab spoke to three scientists who are experts on the carbon process in the production of methane and its impact on global warming, all of whom rejected Professor Plimer’s conclusions as incorrect because he failed to include changes to carbon composition. 

In his article, which has been shared 18,600 times on Facebook since its publication on August 13, Professor Plimer argues “the number of carbon atoms returned to the atmosphere from beef farming is less than that removed by grass growth”.

He goes on to say: “The cycle of atmospheric carbon dioxide via meat production and digestion removes carbon dioxide from the atmosphere and then later releases this carbon dioxide back to its source. What’s the problem?

“Whether grass is used to grow meat, decomposed, or burned, no new carbon atoms are created in this carbon cycle and, by growing beef, some carbon atoms are removed from the cycle for short-term sequestration.”

Professor Plimer writes that his argument is based on a “mass balance calculation” and that no new carbon atoms are created, instead, “carbon atoms are just being recycled”. 

The experts consulted by RMIT FactLab dismissed Professor Plimer’s “mass balance calculation” premise because it ignores the changing chemical composition of carbon in the carbon cycle and how it affects the atmosphere. 

In other words, what’s important is not whether more carbon atoms are added to the atmosphere as a result of beef farming, but whether the cycle of carbon atoms moving from grass, to animals and then into the atmosphere through beef farming (and therefore the production of methane), results in a changed composition of chemicals that ultimately accelerate global warming.

Professor Mark Howden, the director of the Australian National University Institute for Climate, Energy and Disaster Solutions, told RMIT FactLab, ‘’He’s wrong in almost every respect of what he talks about in the article.  

“So, to give a simple example, you can have compounds that have carbon and nitrogen in them, but [they] can have a fundamentally different effect on us humans,” he said.

“If you have a teaspoon of cyanide, which is carbon and nitrogen, you’ll die, but if you have a teaspoon of protein, which is carbon, nitrogen, hydrogen and oxygen, you’ll be fine.

“It is not about the mass balance, it’s about what compounds they are and what function they have in the system of concern,” said Professor Howden, who is also the vice-chair of the UN’s Intergovernmental Panel on Climate Change (IPCC) and chair of the ACT Climate Change Council. 

The University of Melbourne’s Professor of Sustainable Agriculture, Richard Eckard, told RMIT FactLab that Professor Plimer was ‘’ducking responsibility” by “trying to argue [methane emissions] away as a natural process, which they are not”. 

Professor Eckard – who is also director of Victoria’s Primary Industries Climate Challenges Centre – said Professor Plimer’s statement that the number of carbon atoms returned to the atmosphere from beef farming is fewer than those removed by grass growth is self-evident because ‘’soils can store some of this carbon’’.

“What the author misses is that CH4 [methane] is fundamentally different to CO2 [carbon dioxide],” Professor Eckard said. “And for the 14 years that this CH4 molecule exists in the atmosphere, it warms the planet more than 100 times greater than an equivalent molecule of CO2 for every day it is there.”

He added that there were no ruminants in Australia or New Zealand before colonisation, so all methane produced by ruminants in Australia is a result of human intervention. 

Professor Eckard said The Spectator Australia article revealed a “serious flaw in the author's understanding of basic atmospheric chemistry”.

Professors Howden and Eckard both said Professor Plimer’s understanding of how carbon is produced in the agricultural process was flawed.

“There are factual statements in there which are simply wrong,” Professor Howden said. ‘‘It’s not automatic that when grass decomposes it goes up as carbon dioxide. Fire has numerous aerosols and other nitrous oxides can influence the atmosphere in all sorts of ways,’’ he said, adding that this argument showed a “basic lack of understanding of accumulated science in the past 170 years”.

Professor Howden said all methane emissions make the earth warmer than it would otherwise be.

“It’s a simple truth that climate change is demonstrably affecting agriculture across the globe and in most circumstances negatively and is driving agricultural productivity down,” he said.

In April, the IPCC released a report showing that from 2010–19, average annual global greenhouse gas emissions were at their highest levels in human history. 

“Human-induced climate change is a consequence of more than a century of net GHG (greenhouse gas) emissions from unsustainable energy use, land use and land use change, lifestyle and patterns of consumption and production. Without urgent, effective, and equitable mitigation actions, climate change increasingly threatens the health and livelihoods of people around the globe, ecosystem health and biodiversity,” the IPCC reported.

Dr Michalis Hadjiikakou, from the school of Life and Environmental Sciences at Deakin University, said that the body of evidence was clear that methane produced by cattle was accelerating climate change and Professor Plimer’s reasoning in arguing otherwise was “myopic”.

“He ignores the fact that it’s also a question of how many animals you have versus how many animals you had in a pre-industrial context now that farming is on an industrial scale to feed the current demand for dairy and meat.” 

He said this demand for meat had led to large deforestation, further increasing the amount of methane released into the atmosphere.