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The Great Livestock Methane Misconception

methane has short life cycle

The basis of the narrative around the push to cull cattle is that cows produce methane, and that’s true. Methane is a strong greenhouse gas, and that’s also true. So, the natural conclusion is that cows are a big problem for climate change. Here’s where the narrative goes awry. because the conclusion is simply NOT true.

The mainstream media consistently portray cows as pumping additional methane in the atmosphere. This is like saying every shower of rain that falls is new water and adds to the volume of water in the sea and in time we are all going to drown.

Ruminant Livestock Methane is virtually irrelevant as a greenhouse gas. No cow, sheep, or goat has ever managed to create carbon from nothing. Methane from cattle is part of the biogenic carbon cycle which has been around since life began.

Plants capture CO2 from the atmosphere, absorbing the carbon and releasing the oxygen, the carbon is converted into carbohydrates and consumed by the cow where it is digested and some of the carbon is belched from the cow as methane. After an average of 10 years the methane is converted into CO2, and so the cycle continues. [Figure 1]


The Intergovernmental Panel on Climate Change [IPCC] calculates the warming effect of one molecule of methane as being equivalent to 24 molecules of carbon-dioxide over a 100 year. But methane does not live for 100 years. It has a short life remaining in the atmosphere for on average 10 years before it is converted into carbon dioxide and recycled back into grass. Therefore no new carbon is made. It is recycled. As a result of ignoring the recycling and using the 100 year calculation [known as GWP100] Ireland ends up with 12 million tons per annum of emissions which are theoretical emissions that do not reflect reality.

Dr. Frank Mitloehner [1], of the University of California says that “All the media output that you hear assumes that all the methane that’s generated by, let’s say, cattle, adds up, but it doesn’t. At the rate it’s emitted, it’s being destroyed. That makes methane very, very different from the other gases”.

The flaws in the 100 year methodology have been the subject of debate by scientists for decades. They have expressed concern that the currently system dramatically overstates the effect of methane emissions. In the interim other methods were proposed to correct the above anomaly but were not acceptable to some countries including the EU.

Professor Myles R. Allen [2] a Lead Author of the IPCC’s and his team of scientists at Oxford University published data highlighting the flaws in the GWP100 model and have subsequently designed new amendments that deal with the biggest anomalies in GWT100 methodology. This amended version is known as GWP star (GWP*).

GWP star addresses the following anomalies of the GWP100 method

  1. Ruminant methane is rapidly broken down into carbon dioxide; it destroyed in 10 years not 100 years.
  2. Ruminant methane converted into carbon dioxide is recycled into grass growth.
  3. The cyclical flow of Ruminant methane does not add to the stock of methane in the atmosphere.
  4. No new methane is created so ruminant methane cannot create additional warming.

Scientists including Oxford Professor Myles Allen and Professor Frank Mitloehner of the University of California are urging Europe to adopt global climate policy which more fairly accounts for methane that recycles through the atmosphere which at the moment is incorrectly counted as if it accumulates in the atmosphere.

If the EU elects to continue to use the GWP100 model as its future methane policy, pressure will increase to eliminate practices such as ruminant agriculture, scientists have warned.

Since 1974 Irish milk production more than doubled from 3.36 to 8 billion litres per annum. Irish farmers produce twice as much milk per cow than in 1974. As a result Ireland has halved the environmental impact of every litre of milk.

Even the Climate Change Advisory Council [CCAC] charged with the task of providing expert advice to government fail to understand (or choose to ignore) the science that methane is part of the carbon cycle.

1          On Wed July 24th 2019 the CCAC outlined three scenarios A,B,C – to reduce suckler cow numbers. Under scenario C the council proposes that the suckler herd declines to pre-milk quota (1984) levels. This would mean a 53% herd cull. And now October 2021 the CCAC are making more proposals to cut the herd, jettison thousands of jobs and savage our farming families and food production capacity.

2          One would expected that the CCAC would be familiar with the relevant Irish grassland research going back 20 years which showed grassland pulls more carbon out of the air than it puts into the air and that they would also be aware of the August 2019 IPCC  ‘Special Report on Land and Climate’ which shows that global agriculture and forestry every year pulls a net 6 billion tonnes per annum of greenhouse gas out of the air.

3          On the 21st January 2020 Prof. John Fitzgerald chairman of the CCAC addressing a farming event said the following……..“When I took on this job [CCAC chair] in 2015, I thought it was my job to say to you the farming community that you had to get rid of all your cattle. Then I learned that methane is different, and I learned that there may be ways of dealing with methane. [3]

4           In October 2020, Prof. Fitzgerald expressed the opinion that it was not possible to amend GWP100 because we signed the Paris agreement. Prof. Fitzgerald said “I suppose as regards the use of GWP100, the standard one, it is not a choice of the EPA to use that. That is what has been agreed at international level…….  [4]    

But the Paris Agreement does not bind signatories to Kyoto accounting, so Ireland should be able to act on this by setting accurate targets for ruminant methane in recognition of the short life and the cyclical nature of ruminant methane. The obstacle is the EU. The IPCC is not averse to changing the calculation methodology. Brazil, Uruguay & New Zealand are moving to other methods of counting methane.


Other anomalies that need to be addressed in the future in the interest of equity

The farmers or the nation get no credit for the extra greenhouse gas pulled out of the air by grass growth. Every tonne of grass dry-matter pulls 1600 kg carbon dioxide from the air, 1150 kg of Oxygen is returned to the air and 450 kg of Carbon is retained in the grass.

The farmers or the nation get no credit for the 680,000 km of hedgerows individual trees, non-forest woodlands and scrubland all of which adds up to 450,00 hectares all pulling greenhouse gas out of the air.

No offsets are available for the fact that the amount of methane released from a single blade of grass will be the same if it was just left to decompose naturally or if it was eaten by a cow.

Energy released by oxidation of methane should be discounted as it simply replaces an equivalent amount of energy removed from the atmosphere earlier by grass growth.   

What if the pasture was wasted, just left to decompose?

What if the pasture was just left to decompose? Dr. Christine Baes [5] from the University of Guelph, said that it’s important to note that methane is not released by the cows themselves, but the bacteria in their gut. Similar bacteria also exist in the environment and produce methane in wetlands, rice fields and landfills. The actual amount of methane released from a single blade of grass wouldn’t change if it was just left to decompose or if it was eaten by a cow and then digested by the bacteria in their gut.

Satellite images from the ESA that monitors methane in the atmosphere have not detected methane in areas of high cattle numbers. In areas of low industrialisation such as Ethiopia & Sudan where 96 million cattle are kept (25% more cattle than in all of the EU) there is no heightened methane viable by satellite.

In conclusion a more accurate system is a more equitable system. The GWP100 flaws have put undue burden on farmer, food producers and countries with large food production relative to their population, this allowed others to escape shouldering their share of the of the burden.

It is ironic that at a time when Farmers are threatened with cuts to their income and way of life, the EU is negotiating a deal to import beef from Brazil. As with all imports into the EU this beef will arrive with a zero carbon footprint.

More imported beef will reduced production in Ireland and EU; it will also fictitiously reduce the EU carbon footprint. This is outsourcing emissions jobs and incomes.




[1] Dr Frank Mitloehner Professor and Air Quality Extension Specialist at the University of California, Davis

[2]   Dr Allen was a coordinating Lead Author of the The Intergovernmental Panel on Climate Change [IPCC’s] report SR1.5 in 2018. He is head of the Climate Dynamics group at the University of Oxford’s Atmospheric, Oceanic and Planetary Physics Department.

[3] https://www.agriland.ie/farming-news/methane-is-different-from-other-ghgs-climate-council-chair/

[4] Irish Farmers Journal  16th Oct 2020

[5]  Dr. Christine Baes, associate professor in the department of animal bio-sciences at the university of Guelph



Pat Cummins worked for 40 years in the dairy industry

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