Central Queensland cattle producer and grazing consultant Mick Alexander has regularly raised questions in response to Beef Central articles reporting that it takes 10 to 12 years for methane emissions to break down in the atmosphere.
Pointing to online videos of presentations given in recent years by ex-CSIRO scientist Walter Jehne, Mr Alexander says the science shows that methane emissions from cows are naturally broken down as soon as they are released from cattle by hydroxyl ions.
Mr Alexander said that despite conducting research for several years he has been unable to find scientific evidence that definitively proves the length of time it takes methane to break down into carbon dioxide.
“It was first mentioned about two decades ago in literature but without any validation as to who or how it was proven – no scientist has been able to show the science,” he said.
In response to Mr Alexander’s inquiries we have asked a number of scientists and experts in the methane emissions field if they can point us to the original scientific research definitively proving that it takes 10-12 years for methane to break down.
Very few of those we have contacted believe there is any dispute that it takes up to 12 years for methane to break down in the atmosphere.
However, while some have pointed to existing studies or webinars which repeat the position that it takes in the order of 10-12 years for methane to break down, examples of the original scientific studies proving the exact claim have not yet been forthcoming.
Many responded with their scientific reasonings to support the 10-12 year breakdown position, which are outlined below.
Their responses also highlight variation in scientific views around questions such as how long it takes for methane to break down and the effect methane emissions from livestock have on atmospheric warming.
If any scientists reading this article can shed further light on this issue and help to put this question to rest, we welcome your contributions in the comments box below.
Mick Alexander says gaining a clear understanding how the often-quoted 10-12 time frame was arrived at is important because the 10-12 year time frame that the powerful greenhouse gas methane remains in the atmosphere is a fundamental component of calls to curb livestock production.
Hydroxl ions ‘have methane for lunch’
In the above video of a 2020 presentation made in New Zealand, ex-CSIRO scientist Dr Walter Jehne outlines his evidence-based reasoning to explain why livestock should be considered a vital part of the solution to managing atmospheric methane levels.
Livestock – or “mobile biodigesters” – play an important symbiotic role in managing green growing pastures and causing them to transpire water molecules, he explains in the video.
When sunlight hits the water molecules photo oxidisation turns them into hydroxyl ions (along with hydrogen ions) which are the “laundry of the air”.
“That is what cleans up the air, they’re free radicals.. they really gobble up pollutants, – polyaromatic, hydrocarbons, particulate carbons – they are the things that clean up the air big time and of course these guys have methane for lunch, no troubles.”
A cow grazing and maintaining a green pasture that is transpiring will produce 100 times the methane free radicals that it needs to oxidise the methane it produces, he said.
“So when they come and want you to pay for methane emissions for your cattle, you have got to pay that.
“But attached to your cheque for the payment, you have got to attach an invoice, and that invoice is for your cow’s management of grasslands to photo oxidise all the other crap that is going up in the air.
“So you have got to send an invoice to the Government to say, right, yes here is my dollar for my methane and here is my $99 claim for photo oxidisation.”
Dr Jehne said that despite there being large populations of methane-emitting herbivores on the planet including bison, antelope and wildebeest, atmospheric methane levels remained steady at 700 parts per billion for the past million years, thanks to this balancing process.
He said recent rises in atmospheric methane levels in recent decades are attributable to fugitive emissions from mining which followed the collapse of the Soviet Union in 1990 and an abandonment of wells, and the introduction of fracking techniques to free up coal seam gas since 2010.
Methane trapped in continential ice shelves a key concern
In another presentation he has also stated that his biggest concern (from 1:29:38 mark of video) relating to methane is that global warming will continue to release huge volumes of methane currently trapped in continental ice shelves.
“There is about 15,000 billion tonnes of methane locked up in methane hydrates on the continental shelves,” he said
“This is methane effectively as ice crystals and as the oceans warm basically a lot of that has already been releasing.
“If we get a massive release of that methane it is game over higher life. It has happened previously, it is a extinction event.
“And the only thing that is going to save the earth potentially from one of these mass methane extinction events, the only thing that can save the earth is have we got enough green actively transpiring pastures at higher latitude maintained by caribous, reindeer, herbivores to give you enough of this photo oxidisation to neutralise that extinction risk.
“So we have an extinction risk and the question is have we got enough hydroxyl radical from these pastures to neutralise (it).”
Responses from scientific sources
As referenced earlier, Beef Central has previously asked several scientists around the world and people with expertise in methane emissions from livestock for their views on how long it takes for methane to break down.
Summations of the key points they provided in response include:
“Hydroxyl radicals do breakdown methane but only when it gets to the upper atmosphere, because that’s where most are formed by the interaction between ozone and water vapour.
“The idea that it’s broken down immediately is wrong – firstly, as they are not produced in the same place and secondly, hydroxyl radicals are used to scrub more than just methane (methane, sulphur dioxide, carbon monoxide, nitrogen oxides and other organic compounds), but the production is fairly constant in the upper atmosphere, which means if we produce more methane than pre-industrial we run out of hydroxyl radicals to cope with the methane (there are even reports of a hole in the upper atmosphere where there is no hydroxyl radicals anymore).”
“Some people have promoted the theory that soil organic matter can produce hydroxl radicals. Hydroxyl radicals can be generated in soils mediated by oxidation of ferrous iron and/or microorganisms and can then oxidize dissolved organic carbon to carbon dioxide.
“BUT technically this also means the more hydroxyl radicals produced by our soils the more we accelerate decomposition of soil carbon (in humid environments) and release CO2.On average it takes about 10-12 years before a methane molecule makes contact with a OH radical in the atmosphere. To say breaks down instantaneously misses the full story.”
“Methane does break down immediately when it makes contact with a OH radical in the atmosphere. But, that is only part of the story. On average it takes about (with the emphasis on about) 10-12 years before a methane molecule makes contact with a OH radical in the atmosphere.”
“Yes methane breaks down under the action of Hydroxyl ions (the “chemical” pathway listed in technical descriptions of the process). Some of these Hydroxyls may be generated indirectly from transpiration of pastures, but this process is diffuse and takes some years to occur in the atmosphere. The best estimate currently from the IPCC is 11.8 +/- 1.8 years.”
The Climate Media Centre also provided a detailed response to Beef Central questions, replying that it had asked Farmers for Climate Action and experts at the Climate Council and was told there is no such thing as instant absorption/breakdown of methane. “And even if methane was able to break down super fast, we’ve now got so much of it in our atmosphere that it’s playing a key part in warming our planet.”
The Climate Media Centre’s response continued:
“There are some differences in methane produced by livestock and rice paddies (biogenic methane) and methane dug up for burning as fuel. And that is to do with fossil fuel methane adding carbon into the atmosphere overall after it breaks down; livestock burps don’t do that, but that’s a long term thing which confuses a lot of people. The key thing experts say is that methane has a heating effect, regardless of the source.”
Mark Howden and Richard Eckard did a recent webinar with Farmers for Climate Action:
Methane & Global Warming Potential Webinar – 9 Nov 2023 (youtube.com)
The break-down times for biogenic methane are addressed about 12:45 in and 15 minutes onwards.
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- They explain that methane has a half life of 11 years so half of it breaks down within 11 years. It’s definitely not all gone immediately.
- Mark Howden explains that biogenic methane (methane from cattle and rice paddies) does behave differently in the atmosphere to industrial methane dug up from the ground. The carbon atoms in methane from cattle are not adding more carbon to the ‘active’ carbon cycle in the way that burning fossil fuel methane does. But that is over an entire life cycle.
- Also in the webinar the scientists explain the really key thing for the climate is that it’s not so much about the chemical composition as the heating effect of these gases. (The heat is mostly absorbed by the ocean, and warmer oceans play havoc with all our weather / climate systems.)
There’s a blog about methane which explains why there’s so much confusion about the numbers:
https://climateer.substack.com/p/methane-lifetime
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- This blog says that on the breakdown times, everything breaks down over time and the half-life of methane is around 8 – 10 yrs meaning it is all mostly gone by 12 yrs.
- A chunk of the methane does get broken down initially but it takes longer and longer for the rest of it.
- The more methane we have in our atmosphere, the more this whole process slows down.
The Journal Nature
https://www.nature.com/articles/d41586-021-02287-y‘
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- The journal article points out that there are some uncertainties about exactly how much methane is about and where it’s coming from
- It points out many steps we can take to reduce methane would save money, including capturing methane that escapes from gas plants and coal mines, landfill and wastewater plants, and adjusting rice farming practices. These would have a big impact and give more time to find solutions for emissions from the cattle/meat industry.
This article in the Conversation
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- “Fully considered using the 100-year GWP and including natural feedbacks, the IPCC’s reportsays fossil sources of methane – most of the gas burned for electricity or heat for industry and houses – can be up to 36 times worse than carbon dioxide. Methane from other sources – such as livestock and waste – can be up to 34 times worse.”
The United Nations Environment Program explains methane here:
Have a view or any thoughts to share? Let us know in the comments box below.
I think the Climate Media Centre may be misleading people in saying that “there is no such thing as instant absorption/breakdown of methane”. It has been repeatedly proven that methane plays the critical role in the lightning process – particularly in tropical areas. Methane in the atmosphere acts as a pathway or conductor for the lightning and then is wholly consumed the instant the lightning travels down this path. Simple experiments at UWA years ago proved this and the research has been more than exhaustive since then.
Chris Davis
I understood that methane in the atmosphere had a half-life of 9 years, so it is not a major problem, even though we could be led to believe that it is critical to the future of beef production.
I think the Beef Industry is owed an independent peer reviewed study of the Methane emissions from Cattle.
Here is some excellent science that summarises the unknowns in regards to the questions above. https://northlandclimatechange.org/wp-content/uploads/2021/11/methane-review.pdf
I don’t get that it matters. If the ruminant methane from 12 years ago is breaking down now then no net change unless there is a net change in ruminant numbers.
Maintain the rage, Good on you, Mate, JR
Good point that ruminants did no harm to the atmosphere in 10s of thousands of years. That said it is easy to farm ruminants in a fashion that harms the environment but not really that difficult to farm them in a way that enhances the environment and sequesters enough carbon to be carbon positive as well as recharging ground water(minimal run off). Our farm is a case in point ticking all these boxs while producing clean green protein.
This is a very troubling article. Supposedly about science, which is in itself a discipline of absolutes, the responses to this question are merely opinions, views and beliefs. If there is such a gap in the knowledge that we have to fall back on “opinions, views and beliefs” then every thinking person must surely ask :” Why is one “opinion, view or belief” quoted as an absolute while others, no lees equivocal, are simply cancelled as wrong. Do we live in an age of scientific method or have we regressed to an age of alchemy?
This line: “A cow grazing and maintaining a green pasture that is transpiring will produce 100 times the methane free radicals that it needs to oxidise the methane it produces, he said.”
is of most interest to me, as your scientific responders seem to indicate that it takes years for the emitted methane to contact with a hydroxyl ion but they readily admit that once contact occurs the methane immediately breaks down.
So we have 2 views. Walter says via grazing we can foster enough transpiration to support lower atmosphere hydroxyl presence to immediately negate livestock methane emissions and that it since it’s a favourable ratio we can negate a portion of industrial methane emissions in the same moment.
The contrary view seems to simply be that we cannot create enough additional hydroxyl ions via managed transpiration in the lower atmosphere to negate livestock emissions let alone, offset industrial methane.
So it seems we need more scientific data on the relationship between transpiration from green pastures and the associated production of hydroxyl ions please. Though I’d be doubtful that such studies exist.
“Mick Alexander says gaining a clear understanding how the often-quoted 10-12 time frame was arrived at is important because the 10-12 year time frame that the powerful greenhouse gas methane remains in the atmosphere is a fundamental component of calls to curb livestock production”.
This is exactly what the attack on livestock systems are about, whilst ever we go along with the lie that carbon dioxide or biogenic methane are bad for the environment we will invariably and without exception end up at the ‘reduce livestock numbers’ conclusion.
Until agriculture unites on these key issues we are going to be on the receiving end of these activists mindless and unfounded policies.
I believe it is very important to see the evidence about methane please
Now we have a more balanced argument coming from an ex CSIRO scientist which makes you ask more questions than just the one sided climate change claims pushed by the UN
It is amazing how much scientists views vary, but they all push the unscientific value of 10-12 years. the information shows that the half-life for methane in the presence of hydroxyl ions is not 11 years, but more like 11 seconds and thats a stretch. So it seems someone has extrapolated information about degradation, created a half life hypothesis based on a dream and repeated it in scientific literature. And that is now a fact without foundation.
Very interesting Mick.
Thank you fir your work in this area.
Indeed everyone repeating the same statement is NOT the same as providing the original data & study that this statement was derived from.
Without being able to present & replicate the data, it’s not science.
Do you have “the information” that demonstrates that methane breaks down in ~11 seconds in the presence of hydroxyl ions?
And also “the information” of how, when & where when livestock methane encounters these hydroxyl ions?
Thankyou.
This is an important discussion, but also a maddening one. Society has become so enamoured with nitty-gritty “science” (much of which is not actually very scientific at all) & has completely lost all common sense.
To suggest that the natural evolved phenomenon of ruminants grazing grass is any any way bad for the planet is such nonsensical ludicrously. Rather than getting drawn into & overly bogged down in nitty-gritty debatable science, I think that is where our industry should focus. Ruminants are natural. The end.
Hi Michelle, thanks for your question. I do not have the science, however, I am referring to a nature paper from April 2024 – (immediately is the word from this nature article) “As the most important cleaning agent and oxidant in the troposphere, OH can immediately react with various trace gases, such as methane (CH4), volatile organic compounds (VOCs), and carbon monoxide (CO)3,4,5, and accordingly regulate their lifetimes and climate effects6,7,8. ” https://www.nature.com/articles/s41467-024-47436-9 I take immediately as within seconds and certainly not years. We need to force the experts to admit the science does not exist so that real science can be established. the 8-12 years is modelling the atmosphere and not an individual molecule of methane – therefore the half life or lifetime is a misnoma and should be removed immediately. the half life is actually a very small time..
Methane is produced by termites inhabiting almost all the fallen trees in this country and possibly across the world, so when you legally push scrub, do you burn it or wait for the termites to demolish it?
The biggest problem facing the world today is over-population. Forget the rest.
Well done Mick Alexander for calling this out for what it is.
The science fraternity and the Trillion-dollar climate change industry despite all their resources can’t produce any actual evidence linking livestock ’emissions’ to changes in the weather, and its way past the time for us to be pushing back.
Livestock play a critical and important role across all of the world’s rangelands, as well as providing humanity with the most nutrient dense food on the planet. The demonising of them should be stopped, and all the positives real scientists such as Walter Jehne talk about be promoted.
Can any of the critics cited above claiming that he is wrong explain why the atmosphere remained unchanged till very recently?
Please note that the “half life” quoted for methane breakdown is usually the “e-fold” life not half-life from memory, about 37% of mass remains not 50%