Splitting Gases not Atoms or Hairs

Ernest Rutherford, was a famous New Zealander, famous enough to be placed on the $100 note, when his more famous compatriot, Hilary, only made it onto the $5 edition of the currency. Rutherford is credited with first splitting of the atom and before achieving this he worked diligently for many years. Because achieving important breakthroughs can be a slow and frustrating business and this is certainly also true of progress in reducing Greenhouse Gas Emissions from farms. 

Part of our work at VetSalus includes communication and education about important issues linked to One Health and sustainability and one of the key themes, which we have visited on numerous occasions, has been the accuracy of the reporting of greenhouse gas emissions, particularly methane. (If you would like to read the back series of articles on this subject please visit www.vetsalus.com and search “methane” - there are over 30 items listed.) 

It is thus pleasing to see recent changes in the thinking of the New Zealand government on this topic, including the recognition that a “split gas” approach is much more in line with the actual science of greenhouse gas emissions. Politicians are not always eager to assimilate scientific facts into their policies, so the recognition of the split gas approach, which has been advocated by a number of organisations internationally and within New Zealand, is very welcome progress. 

Split gas of course has nothing to do with splitting atoms. The term is now usually applied to the separate reporting of gas emissions, by each type of gas rather than all being ‘lumped together’ and referred to as carbon dioxide equivalents. Not all greenhouse gases were created equal. The three major planet warming gases linked to farm emissions (carbon dioxide, methane and nitrous oxide) have major differences in the length of time they endure in the atmosphere and thus vary considerably in their warming impact. While carbon dioxide and nitrous oxide persist for considerably more than a hundred years, methane concentrations fall rapidly and have largely disappeared by year twelve. Methane is, of course, the most potent global warmer of the three but this means that relatively small reductions in methane can have major cooling effects. This difference has been known for many years but pleas to measure these gases differently have fallen on largely deaf ears; the Global Warming Potential 100 (GWP 100) has been solidly based on carbon dioxide as the benchmark. (If you are so  inclined, you can read more of the detailed science background on this in this paper published in Nature in 2022 [1].)

Reporting the warming effects of each gas independently leads to a more accurate, and fairer, picture being presented. It is also relevant that the methane produced by farm emissions is part of a complex carbon cycle, the biogenic cycle, and has not originated from fossil fuels: they are not involved in releasing new carbon into the atmosphere. And there are other sources of methane in the atmosphere including wet rice paddies and leaking oil wells.

Despite this trend towards a better measurement system, there is still a need to reduce the emissions of methane, and other greenhouse gases from farms. Much progress has already been made here. In New Zealand, Beef and Lamb NZ report that, since 1990, emissions from beef and sheep farms have already been reduced by 30% [2]. Indeed a report published in 2023, based on Life Cycle Assessments, suggested that New Zealand beef and lamb has one of the lowest global farming carbon footprints [3].

VetSalus is a member of the Global Roundtable for Sustainable Beef, which is an influential international body. It has recently produced a position paper on the role of sustainable beef in nutritious diets [4]. The paper recognises that many western diets contain too much meat but also points out that animal husbandry standards vary considerably across the planet; and improvements in animal welfare and health automatically bring reductions in emissions and improved sustainability. The paper also makes the important point that: “The interactions between the health of the land we use to produce food on, the people who eat it and the livelihoods of those who produce it are numerous and complex.” Farming systems and their products need to be fully evaluated and compared on a level playing field. For example, there will be significant differences in the carbon footprints of well managed grass fed beef and intensive feedlot beef; beef from poorly managed systems will also differ. Simple and sweeping “beef is bad” statements just do not do the complexity of the situation any justice: details like split gas reporting matter enormously. 

For many years veterinarians have been involved in improving farm productivity. Vaccination programs improve lambing percentages; increased fertility brings better calving percentages and less wastage. What was once called preventative medicine might now be better named "sustainable medicine”? VetSalus consultants are closely involved with the education and implementation of improved farm productivity and reduced carbon outputs.

The wider recognition of the need for more accurate, split gas reporting does not mean that everything is sorted; there is still much work to be done internationally and the minimal outcome of the recent COP30 meeting does little to inspire confidence. But a wider recognition of the need to more accurately report greenhouse gas emissions from farms is to be welcomed, even if it only represents one small step forward. 

The science is complex and the details do matter. Ongoing work to improve animal health and productivity will bring real results in the form of reduced methane outputs and that is something that VetSalus is dedicated to achieving. Split gas reporting is another important detail and in stating this I am not splitting hairs!