Allan Barber finds that 'new' research needs to be assessed critically when it comes to climate claims. A grass-fed vs grain-fed study raises issues that apply widely

When scientific research reaches an interim conclusion and the publication of a study, it is important to see this for what it is: a theory apparently supported by a series of results, but still requiring extensive peer review and reconciling with all known facts before it can be generally accepted as completely accurate. It is important to fully understand the underpinnings of the research and interrogate and test to ensure that the conclusions it reaches are sound. 

The constant changes and additions to the science around climate change bear out the extreme challenges of arriving at absolute certainty about what is right or wrong while different governments take contrasting positions on how to address the issue.

In case the readers think I have gone off on an irrelevant tangent, my interest was spiked by a recent article in Beef Central by US based meat and livestock commentator Steve Kay who I believe to be a New Zealander by birth. He refers to what he calls “groundbreaking research” by Californian think tank Breakthrough Institute which claims conventional wisdom about the lower carbon footprint of grassfed versus grain fed beef may be misplaced. The study covers 100 beef operations from 16 countries (not New Zealand) and, using a new approach of calculating soil sequestration and the carbon opportunity cost of using land for production, finds the carbon footprint of grassfed cattle to be 42% higher than grain fed.

Rather than discussing the merits of grain fed versus grassfed beef, the study simply concludes “the lowest-carbon beef typically comes from the most productive operations; that is those that produce the most beef per acre of land.”  The authors introduce a new argument that carbon footprints should take account of land use when considering beef’s carbon footprint and improving the productivity of beef production globally could have outsized climate benefits.

With all due respect to the academic credentials of the report’s authors, they appear to have assumed the world’s beef production should and can be concentrated in the most fertile areas, regardless of the needs and ambitions of producers in less productive regions like Africa or India.  They also take a narrow view of what is good for the environment and animals from a climate perspective, focusing on producing as much as possible on the smallest possible amount of land; this ignores the less profit-focused benefits of free-range production such as biodiversity and animal welfare, quite apart from reducing the stress on farmers of constantly striving to maximise rather than optimise production.  

B+LNZ previously commissioned a study by AgResearch which used the current globally accepted methodology to provide the lifecycle assessment of all inputs involved in the production, transport, sale and consumption of beef and sheep meat on the average New Zealand farm.

Andre Mazzetto is the scientist at AgResearch who is working closely with B+LNZ to identify the main factors that differentiate New Zealand grassfed production from both grain fed and other countries’ production methods. Mazzetto says our agricultural production has a lower environmental footprint than the United States for example because 90% of the emissions are incurred on farm where New Zealand’s soils are heavy in carbon for which our farmers should be given credit because they are not depleting the carbon content, whereas in the USA soils must constantly be replenished.

Mazzetto suggested, although the Breakthrough Institute study had been peer reviewed and validated, it was not entirely reliable for several reasons: the sample base was too small, there was inadequate allowance for regional variations, there was no discussion of short-lived gases like methane which are prevalent in grassfed production, and it introduced a new concept to the calculation, the carbon opportunity cost of land use for beef production and soil sequestration. The study’s grassfed production conclusions were based on conditions in Northern Australia where it is very dry with little vegetation, diametrically opposed to conditions in New Zealand. Also, there was no counting of sequestration from woody vegetation.  As research by the Ministry for the Environment shows, the woody vegetation on New Zealand sheep and beef farms is sequestering at least 30% of total emissions from on farm. 

The approach of the Breakthrough Institute’s study team compared with that of AgResearch illustrates the motivations of the two organisations from different countries with differing motivations. One has used a new approach to the methodology, but only taken some aspects into account like land use and soil sequestration potential, without including critical aspects like existing soil stocks and the sequestration potential of woody vegetation.

This area of research and the conversation will continue to evolve. It is important that organisations like B+LNZ work closely with AgResearch who are well plugged into the conversation to make sure the full picture is examined when researching new methodologies.

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