Death, methane and taxes

Life existed long before the modern human, and it will persist long after us. Even in the event of nuclear fallout, microbial life will very likely remain.

The presence of microbial life – and the byproducts they create as they respire – is a foundation critical to the balance of all of Earth’s ecosystems. It’s a foundation we take for granted, likely because we’re not able to see it. But everything from soil health, fermentation of some of our favorite foods and drinks, and human and animal digestion would be impossible without single-celled organisms that have no care or recognition of our existence.

Methanogens – microbes that were once believed to be bacteria but technically belong to the domain Archaea – are no different. They are named after one of the byproducts of their metabolic process: a carbon-containing greenhouse gas (GHG) called methane, or CH₄. Methanogenesis, the creation of methane, is believed to be one of the oldest metabolic processes on the planet, a relic of a time when the planet was greatly deficient in oxygen. Many methanogens thrive in extreme conditions. However, many find residence in the warm, oxygen-devoid, pH-neutral environment of rumens and hindguts.

These archaic microbes provided digestive balance to their hosts for millennia, and in return receive a dark, welcoming home. Their numbers are small – they only make up 2 to 4 percent of the total mass of all ruminal microbial life. Yet, they create important equilibrium in the historically carbohydrate-rich environments fostered by the ingestion of fibrous feed. When ruminants eat, other rumen bacteria digest the feed’s carbohydrates to produce energy for the animal, resulting in the creation of volatile fatty acids. This process also produces hydrogen and carbon dioxide (CO₂). If the hydrogen ions are not removed, the rumen can become acidic. Methanogens step in to prevent this by using the hydrogen and CO₂ for their own growth, producing methane gas in the process. This methane is then expelled from the animal through burping, effectively maintaining the balance of the rumen environment.

We are just as much part of the natural world as we are part of the world created and maintained by human-centric ideology and systems. Human-induced changes to atmospheric temperatures are nearly indisputable. What is disputable, is who to blame and to what degree, and how to reduce our impact.

In the human-centric world, taxes are inevitable. Taxation is meant to benefit the greater good, yet many have the means to find or create loopholes to avoid contributing a fair share. None of this is news. However, some recent news out of Denmark is unsurprisingly stirring some controversy: they will be the first country in the world to impose a tax on farmers according to their CO₂-equivalent (CO₂e) production.

This begs the question, what is a normal and acceptable amount of food production-related GHG emissions for a growing population? The answer, biologically, cannot be zero. Food production means growing life to sustain life, and metabolic processes that produce gaseous byproducts are evidence of those life-giving processes. A “net zero” is potentially possible, as other biological processes exist to facilitate the removal and sequestration of these gases into plant structures and soil. Although human-made processes exist to capture and store carbon underground, natural processes remain the simplest and most reliable way to balance our global carbon ledger.

Is the “stick” approach to methane reduction via taxation sustainable for the long haul? There are too many moving parts in the equation to truly know. It is true that methane is a potent GHG; the most commonly used index estimates it to be 28 times more effective at trapping atmospheric heat than CO₂ (based on the GWP100). It is also true that for Denmark, the agricultural sector represents the greatest emitter of GHGs (25% in 2021), although this is closely followed by transportation (24% in 2021).

Still, in an attempt to reduce Danish GHG emissions by 70% from 1990 levels by 2030, Danish farmers will be taxed 120 kroner ($17.30) per metric tonne of CO₂e and increase to 300 kroner ($28.30) by 2035.

How potent will this tax burden be for Danish producers? Here is one example:

• The average dairy producer in Denmark has about 130 cows.
• Denmark has some of the EU’s most productive dairy cows, producing an average of 38 kg (83 lbs) of milk per day.
• Press releases of this news report an estimated 6 metric tonnes of CO₂e production per cow per year in Denmark. This equals roughly 780 metric tonnes of CO2e per year for the average Danish dairy herd.
• 6 metric tonnes/year = 16.4 kg CO₂e/d. At 38 kg milk/d, this equals a fairly low 0.43 kg CO₂e per kg of milk produced. For comparison, one US average predicts 1.3 kg CO₂e per kg of milk produced (though I am unsure if the same inputs were used between these two estimates).
• This would equal a tax burden of $13,494 in 2030, and $22,074 in 2035.
• At 46.65 euro/100 kg milk (approximately $22.96/cwt), a Danish dairy producer would make ~$753,627 in gross profits this year from their milking string.
• If milk prices did not rise, a Danish dairy producer will be taxed at 1.8% in 2030, then 2.9% of their gross profits in 2035 simply because their cows exhale.

It’s simple to deduce that this gap in already tight profit margins will need to be made up by 1) reducing the CO₂e produced overall by the herd and/or 2) passing on the extra cost to consumers. To reduce the GHG production of the cowherd, CO₂e will either need to be reduced per kg of milk produced, or cows will simply need to be culled. The reduction of cows overall will mean less food, and a significant loss of income and jobs for people working in the dairy sector.

Reduction of methane within an animal is possible through management, feed additives, and genetics. Again, methane production likely cannot be zero – remember, methanogens are there for a reason. However, there are ways that agriculture can step in to improve the overall emission of carbon into our atmosphere, whether or not it is believed that agriculturalists should be the ones to do it. The problem is that we currently rely primarily on modelling, i.e., making educated estimates, to estimate the carbon footprint of an operation.

Tools that record true GHG measurements exist in research settings, but are currently far out of reach for the average farmer. It will be some time until these measurement tools can be scaled or subsidized to the farm level. Until then, taxing farmers in an effort to reduce herd sizes and/or imposing extra costs on consumers is likely premature and risks disrupting local economies and food production systems.

-JPW