War on Methanogens based on Flawed Reasoning
#climate changes
war on nature
Methanogens: Essential Partners in the Rumen, NOT Opportunists.
The New Zealand Government, through the Agricultural Greenhouse Gas Research Centre, the Pastoral Greenhouse Gas Research Consortium, and AgResearch, is spending millions of taxpayer dollars developing vaccines and chemical inhibitors and GE forages and GE probiotics designed to suppress methane-producing microbes in the rumen of livestock. These organisations claim methanogens are “not thought to be essential” and are merely “opportunists” in the digestive system of ruminants [2].
The justification is flawed, and could not be further from the truth.
Methanogens are not freeloaders. They play a specialist microbial role in the rumen and their activity is essential for rumen function. Suppressing them risks undermining the very process that allows ruminants to convert grasses into meat and milk—the foundation of New Zealand’s pastoral economy.
Yes, methane is a greenhouse gas, but the idea that livestock methane is driving global increases remains unproven. Satellite data consistently show that the largest methane emissions come from the Northern Hemisphere — linked to fossil fuels, industrial activity, and natural wetlands. Ruminants are only one of many contributors.
Role of Methanogens in the Rumen
Hydrogen Sink: Main Function
When rumen microbes ferment feed, large amounts of hydrogen (H₂) are released.
If hydrogen accumulates, fermentation is inhibited and digestion slows.
Methanogens, a unique group of Archaea, consume hydrogen by combining it with carbon dioxide (CO₂) to form methane (CH₄).
This process stabilises the rumen environment and allows fermentation to proceed efficiently.
Maintaining Redox Balance:
By removing hydrogen, methanogens create the conditions for other microbes—bacteria, protozoa, and fungi—to continue breaking down cellulose, hemicellulose, and starch.
Without this hydrogen clearance system, fermentation would stall and ruminants would be unable to extract sufficient energy from fibrous feed.
Why Methanogens Matter
For the Animal
Enable efficient digestion of fibrous diets such as pasture.
Support the production of volatile fatty acids (VFAs)—acetate, propionate, and butyrate—that provide the majority of a ruminant’s energy supply.
Maintain a balanced microbial ecosystem critical to animal health.
For the Environment
It is true that methane is a greenhouse gas. As a trace gas methane is one of 5 greenhouse gases. In NZ, Water Vapour is 96% of all Greenhouse gases, CO2 3.9%, Methane 0.02%, Nitrous Oxide .003% and Ozone 0.0004%.
Around 6–10% of the ruminant’s gross energy intake is lost as methane. However, this energy “loss” is the price paid for keeping the rumen stable and productive. Without methanogens, both feed efficiency and hydrogen management would collapse.
Ruminants contribute roughly 10–14% of anthropogenic methane emissions, but they are only one of more than ten significant methane sources.
Crucially, there is no clear, quantifiable evidence showing that ruminant methane is the primary driver of rising global methane concentrations. Satellite data indicates that the largest increases are in the northern hemisphere, where fossil fuel extraction, waste management, and industrial sources dominate.
The Real Risk
By framing methanogens as “opportunists” and “non-essential,” researchers justify expensive interventions to suppress them.
Yet methanogens are integral to the rumen ecosystem and to the animal’s ability to thrive on fibrous pastures. Interfering with this system—whether by vaccines, inhibitors, or genetic manipulation—risks destabilising one of the most successful biological partnerships in agriculture - all for uncertain gains.
The real question is not whether methanogens are essential—they clearly are—but whether undermining them is worth the risk to ruminant productivity, animal health, and food security, all while chasing climate benefits that remain uncertain.
Just as we would hesitate to take a product that disrupts our own gut microbiome — knowing how vital it is to our health — why would we introduce something to our animals that interferes with theirs, especially when it offers them no health benefit just the possibly of less belching?
Summary
Methanogens are essential, not opportunistic. They are the hydrogen managers of the rumen, enabling the fermentation process that fuels New Zealand’s grass-fed livestock industry. Suppressing them may reduce methane, but it also undermines the very system that allows ruminants to efficiently convert pasture into food. Before pouring millions more taxpayer dollars into vaccines and inhibitors, policymakers should recognise that disrupting methanogenesis could cause far greater harm than the methane itself.
References
[1] Reducing New Zealand’s Agricultural Greenhouse Gases: Methane Inhibitors. NZ Agricultural Greenhouse Gas Research Centre, Pastoral Greenhouse Gas Research Consortium. 2017. www.pggrc.co.nz/files/1501479614891.pdf
“In the rumen, methanogens modify the fermentation process, but they are not thought to be essential to the host animal. They are opportunists…” (NZAGRC/PGGRC Fact Sheet)