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3 myths debunked: Animal agriculture’s real impact on the environment

October 10, 2022
tags: ,

By Paul Homewood


I was sent this article from two years ago, and it is relevant to the debate on agriculture’s impact on GHGs:




The way the public and the media perceive animal agriculture’s environmental impact can, and should, change. New research from Oxford University and the University of California, Davis have recently debunked some of the most critical and long-standing myths surrounding animal agriculture. But can this breakthrough overcome animal agriculture’s bad reputation?

The current narrative about animal agriculture says that ruminant livestock animals (e.g., beef cattle, dairy cattle, etc.) produce methane. Methane is a potent greenhouse gas. Thus, animal agriculture is bad for the environment.

During a keynote presentation for the Alltech ONE Virtual Experience, Dr. Frank Mitloehner, professor at the University of California, Davis and air quality specialist, boldly proclaimed a path for animal agriculture to become climate-neutral.

Yes, “you heard me right — climate-neutral,” said Dr. Mitloehner. He said he would like to, “get us to a place where we have the impacts of animal agriculture that are not detrimental to our climate.”

3 myths about animal agriculture’s environmental impact debunked

Myth #1: Methane (the most common greenhouse gas, or GHG, in animal agriculture) acts just like other GHGs in the environment.

Fact: The three main greenhouse gases, carbon dioxide, methane and nitrous oxide, all impact the environment in critically different ways, especially as it relates to their source, life span in the atmosphere and global warming potential.

Carbon dioxide and nitrous oxide are known as “stock gases.” Stock gases are long-lived gases and once emitted will continue to build up in the atmosphere. Carbon dioxide, for example, has an estimated lifespan in the atmosphere of 1,000 years, meaning carbon dioxide emitted from the year 1020 may still be in the atmosphere today. Methane, on the other hand, is a “flow gas.” Flow gases are short-lived gases and are removed from the atmosphere at a more rapid pace. Methane’s lifespan in the atmosphere is approximately 10 years. This means a flow gas like methane would impact the environment for a duration that is nearly 100 times shorter than the stock gas carbon dioxide.

What causes these gases in the first place? Carbon dioxide is created by the burning of fossil fuels. Fossil fuels are used as the energy source to power most homes, vehicles and industry globally. As the graph below depicts, Dr. Mitloehner refers to stock gases like carbon dioxide as a “one-way street” because they only accumulate in the environment over time due to their long lifespan.

Methane can be produced in a variety of methods, but most commonly, it’s produced through the rumination process in beef and dairy livestock (i.e., belching). As a short-lived flow gas, “The only time that you really add new additional methane to the atmosphere with the livestock herd is throughout the first 10 years of its existence or if you increase your herd sizes,” explained Dr. Mitloehner. Methane levels do not increase if herd sizes remain constant because methane is being broken down at the same rate it is being produced.

“What I’m saying here by no means (is) that methane doesn’t matter,” he continued. “While that methane is in the atmosphere, it is heat-trapping, it is a potent greenhouse gas. But the question really is, do our livestock herds add to additional methane, meaning additional carbon in the atmosphere, leading to additional warming? And the answer to that question is no. As long as we have constant herds or even decreasing herds, we are not adding additional methane, and hence not additional warming. And what I just said to you is a total change in the narrative around livestock.”

Alternatively, carbon dioxide is created from extracting fossil fuels that are millions of years old and are trapped under the Earth’s surface.

“These long-lived climate pollutants are only emitted,” said Dr. Mitloehner. “They are put into the atmosphere, but there’s no real sink for it in a major way.”

This demonstrates that carbon dioxide and methane are very different types of gases (stock versus flow) and have very different lifespans in the environment (1,000 years versus 10 years), but what about their global warming potential?



Myth #2: The current method for assessing the global warming potential (GWP100) of greenhouse gases properly accounts for all important variables.

Fact: The initial method for calculating GWP100 misrepresents the impact of short-lived flow gases, like methane, on future warming. The new “GWP*” is an improved and more representative measurement.

The initial GWP100 measures produced by the Kyoto Protocol nearly 30 years ago marked a very positive step for assessing global warming. The initial documents included many footnotes and caveats to account for variability and unknown values. “But the footnotes were cut off, and people ran with (it),” said Dr. Mitloehner. “And in my opinion, that was a very dangerous situation that has really gotten animal agriculture into a lot of trouble, actually, quite frankly.”

The current GWP100 measurement generates an over-assessment of methane’s contributions to global warming. Currently, in short, GWP100 measurements are all standardized to a billion tonnes of carbon dioxide equivalent. So, all non-carbon dioxide emissions are converted by multiplying the amount of the emissions of each gas by its global warming potential over 100 years value. Methane has a GWP100 value of 28, meaning it is 28 times more potent than carbon dioxide in the atmosphere.

Unfortunately, this type of calculation completely omits the fact that flow gases, like methane, are destroyed after approximately 10 years and would not continue for the entire 100-year duration as described in the GWP100 formula. Additionally, it underestimates the impact that stock gases, like carbon dioxide, would have that persist in the environment for 1,000 years.

Dr. Mitloehner cited Dr. Myles Allen from Oxford University as the pioneer of a new calculation called “GWP*.” The new GWP* calculation better accounts for both gas intensity and gas lifespan in the atmosphere in its measurements of global warming. This is a new narrative to explain global warming emissions and, Dr. Mitloehner said, “you will see it will gain momentum, and it will become the new reality” soon.



Myth #3: To keep up with increasing demand and global population growth, the United States has continued to increase its numbers of beef and dairy cattle, thus increase methane emissions.

Fact: The United States reached peak beef and dairy cattle numbers in the 1970s and has reduced its number of animals every decade since, resulting in 50 million fewer cattle in total.

Over the last half-century, the United States has made tremendous progress to improve efficiency and increase productivity while also reducing total beef and dairy cattle numbers. For example, in 1950, the U.S. dairy cow herd peaked at 25 million cattle. Today, the dairy herd is approximately 9 million cows, yet it is producing 60% more milk — that’s significantly more milk with 14 million fewer cows!

Though cattle numbers have continued to increase in countries such as India and China, this means the United States has not increased methane output — thus not increasing GHG contributions from livestock — over the last five decades.

This first myth of the article really goes to the heart of the issue. As Dr Mitloehner explains, the global stock of methane in the atmosphere will not increase unless herds increase around the world. And even if you do away with all cattle, the reduction in methane levels is only ten years worth.

There are of course other factors not taken into account here. If we do abolish all livestock, how do we replace that food? All types of food production, whether arable or not, involve the emission of GHGs, not least in the use of fertilisers, which would inevitably increase without the availability of manure.

  1. Gerald Ratcliff permalink
    October 10, 2022 12:20 pm

    “What causes these gases in the first place? Carbon dioxide is created by the burning of fossil fuels”
    I stopped reading when I read the above.

    • Chaswarnertoo permalink
      October 10, 2022 3:14 pm

      And it stays in the atmosphere….. utter BS.

      • Harry Passfield permalink
        October 10, 2022 4:04 pm

        And it (methane) ‘traps’ heat. Traps?

      • catweazle666 permalink
        October 10, 2022 4:23 pm

        Aside from having a very short half-life, the methane absorption spectrum is covered by that of water vapour, so it has little or no effect.

      • October 11, 2022 7:34 am


        this fact sems to have escaped much of science and ‘scientists’ and is similar to CO2 in that respect.

        As is this quote from the article Myth 1 :-

        “Fact: The three main greenhouse gases, carbon dioxide, methane and nitrous oxide, all impact the environment in critically different ways, especially as it relates to their source, life span in the atmosphere and global warming potential.”

        Omitting in listing the three main greenhouse gasses, the most potent in terms of atmospheric concentration and the breadth of spectrum of infra red radiation it traps being H2O.

  2. Charlie Flindt permalink
    October 10, 2022 12:51 pm

    The ‘cows cause climate change’ came along just in time for the vegan mob, as their ‘we don’t kill animals’ argument had been well and truly debunked. For a time, they looked a bit short of outrage fodder.

  3. bobn permalink
    October 10, 2022 12:55 pm

    And this is from a devout global warmista. Many of his assumptions are wrong (the idea CO2 stays in the atmosphere for 1000yrs is pure poppycock – he hasnt heard of the carbon cycle!). he talks of ‘the three main greenhouse gases’ without mentioning the giant big daddy greenhouse gas – H2O.
    So while he is a warmist who buys all the fake alarm scientology he still concludes that cattle are not a problem for the climate – and he’s an alarmist who’s saying it!

    • Broadlands permalink
      October 10, 2022 1:23 pm

      Bobn is correct. “These long-lived climate pollutants are only emitted,” said Dr. Mitloehner. “They are put into the atmosphere, but there’s no real sink for it in a major way.” The major way is called aerobic respiration, the stoichiometric reverse of oxygenic photosynthesis is what recycles organic biomass. Unless the carbon is buried away from some of the oxygen it helped create it remains part of the Earth’s natural carbon cycle. The exception is biocarbonate…invertebrate shells. They store CO2 as calcite and aragonite. And have been doing so for a billion years.

  4. Orde Solomons permalink
    October 10, 2022 1:29 pm

    Funny how when discussing dangerous methane emissions from farmed cattle, they never mention the millions upon millions of North American bison which wandered around in the centuries before they were exterminated with the rifle in the 19th. Or are they presuming that bison didn’t emit methane? Or don’t they think at all?

    • johnbillscott permalink
      October 10, 2022 1:58 pm

      I was going to make a similar statement. With the elimination of Bison there was a significant reduction in animal methane production in North America. Now vegans are emitting methane because of their unhealthy diet.

    • catweazle666 permalink
      October 10, 2022 2:59 pm

      And don’t forget the millions of wildebeests, zebras, antelopes and other herd animals that migrate annually across the African plains!

      • Nigel Sherratt permalink
        October 11, 2022 10:02 am

        and the termites! (not migrating of course)

    • Chaswarnertoo permalink
      October 10, 2022 3:16 pm

      Greentards have never been known to think. That’s why they’re greentards, much like socialists.

      • catweazle666 permalink
        October 10, 2022 4:37 pm

        They ARE Socialists, hence the epithet Watermelons, Green on the outside, Red on the inside.

  5. October 10, 2022 1:37 pm

    The fraudulent AGW scam is totally corrupt and mendacious.
    Its UK authors should be sent to the Antarctic on a one way ticket, or gagged, perhaps to asphyxia.

    These include Ed Milliband and the Climate Change Committee, along with Mrs Bo Jo.

  6. Brian Smith permalink
    October 10, 2022 2:07 pm

    If we eat the grass that our cattle used to eat won’t we emit the methane instead? Just a little more politely. Hopefully.

    • October 10, 2022 3:06 pm

      That is the reason why sheep and cattle exist … we can’t eat the grass that covers vast areas of land, in particular the land that is unsuitable for arable farming. If only there were animals that could convert grass into food and other useful products …

      • Brian Smith permalink
        October 10, 2022 3:14 pm

        I wasn’t being entirely serious but the point remains; if we are forced to eat vegetation of one sort or another, we will use the same digestive processes cows, sheep, goats etc use to break it down in our stomachs and we will, therefore, produce methane, as they do, and in the same amount.

  7. John Warren permalink
    October 10, 2022 2:53 pm

    CO2 may last in the atmosphere for 1,000 years, and the hidden suggestion is that therefore it is rapidly increasing. No account has been taken of the fact that green plants absorb CO2 therefore reducing the amount in the atmosphere. The slight increase of CO2 that does take place increases the ability of plants to manufacture food products. This is a net gain, as I see it

    • catweazle666 permalink
      October 10, 2022 10:01 pm

      Yes, a net gain and we also benefit from being able to eat the animals that graze on them too.
      But actually, vastly more CO2 is absorbed by the flora and fauna in the oceans than the greenery on land.

  8. 2hmp permalink
    October 10, 2022 3:23 pm

    CO2 stays in the atmosphere ? Has he never heard of photosybthesis. ?
    What line is he promoting ?

    • D Hynes permalink
      October 10, 2022 7:09 pm

      CO2 is heavier than air, and it naturally sinks downwards. How can it remain up in the atmosphere?

  9. October 10, 2022 4:47 pm

    The whole of this article becomes totally IRRELEVANT when you know that the CO2 GHE is HALTED when the water in the atmosphere reaches about 4.2%. which seems to be current global average and stable.

    Also ; as the evaporation of Water occurs at CONSTANT temperature it provides a net NEGATIVE feedback to any warming whether by the GHE or otherwise.

    Why we sceptics get sucked into this absurd debate about cow farts, by swivel-eyed vegans I-know not.

  10. Bernard Taylor permalink
    October 10, 2022 6:02 pm

    The bulk of plant material is cellulose – which human beings are unable to digest. Ruminants, like cattle and sheep can. We, in turn, can digest ruminants and their milk. There is an enormous amount of cellulose which is a by-product of the food industry. This is converted into human food. Without cattle it would go to waste. In addition there are vast areas of land which are unsuitable for arable but which will grow a bit of grass. This feeds millions of people. Feeding the world’s population is touch and go at the best of times and these aren’t the best of times. We cannot do without the very special ability of ruminants to convert cellulose into human food.
    It further occurs to me that if cellulose is not being fed to ruminants it would break down anyway. Inevitably much of this would take place under at least partly anaerobic conditions. So methane would be produced anyway.

    • David V permalink
      October 10, 2022 8:56 pm

      Methane is otherwise known as marsh gas – largely forgotten these days but that is exactly what happens when not consumed before rotting.

      • Dave Andrews permalink
        October 12, 2022 5:18 pm

        Marsh gas.
        And what better way to create marshes than doing it naturally by returning beavers to the wild so they can build dams and create their own marshes just as all the rewilders want?

  11. heatherclad permalink
    October 10, 2022 6:04 pm

    I agree that this article has omitted any mention of the most important greenhouse gas, which is water vapour.

  12. MrGrimNasty permalink
    October 10, 2022 6:31 pm

    Another BBC fishy tale in a climate of confusion.
    A half hearted effort to include climate change in this one, but their logic fails.

  13. D Hynes permalink
    October 10, 2022 7:04 pm

    Before Europeans began cattle farming in America, there were vast herds of buffalo roaming the countryside, which would have produced significant quantities of methane . The buffalo were largely massacred by the Europeans, often quite mindlessly without making use of the dead animals.

    • Phoenix44 permalink
      October 11, 2022 7:42 am

      I’ve seen it claimed bison produce much less methane than modern cattle but I’m not sure if that’s a proven fact.

  14. October 10, 2022 7:24 pm


  15. October 10, 2022 7:30 pm

    Hi cognog2-Ido not understand your two statements above cocerning “water vapour”.Could you enlarge a little or point me to some refs.
    Much appreciated.

  16. Ben Vorlich permalink
    October 10, 2022 8:39 pm

    Am I missing something? In the table of gasses
    Nitrous oxide | N2O not C2O

  17. M E permalink
    October 11, 2022 4:24 am

    Climate change: Government’s planned emission charge for farmers gets mixed reaction qv.

  18. Phoenix44 permalink
    October 11, 2022 7:41 am

    If anybody thinks this will slow down the Vegans/Vegetarians they are naive. And they are a key part of the Climate Coalition, so must be kept on board. This stuff will sink without a trace. It’s not about facts or solutions, it’s about busybodies getting what they hate banned and getting everybody to behave as they think they should.

  19. Steve permalink
    October 11, 2022 9:26 am

    The politicians promoting the net zero agendas also miss the devastating effect of withdrawal of animal excrement on soils. It has been shown that cattle prevent desertification.
    Also, if it were not for grass grazing, our high hills such as the South Downs would have to be wooded and there would be no long distsnce views.

  20. Ben Vorlich permalink
    October 11, 2022 9:51 am

    I’m going to be banned from complaining to the BBC.

    Separately, I have been reviewing the history of your complaints to the BBC.

    The BBC’s Complaints Framework is publicly available, and I would refer you to Annex B. This explains the steps the BBC may take if it considers there is misuse of the complaints service.
    Since June you have submitted approximately 17 complaints to the BBC, which focus on science and environment stories and seem to be informed less by the facts of the matter and more by your own views.

    As the complaints framework points out:
    “…the BBC devotes considerable resources to handling complaints, and in fairness to everyone – other complainants, BBC staff and the public at large who pay the licence fee – it is right that we should try to focus those resources on complaints that raise significant issues and substantial concerns”.

    While we continue to review and respond at this stage, we believe many of these complaints are clearly without merit and so I am writing to make you aware that should this pattern continue, we will need to consider applying Annex B to the complaints we receive from you, in order to ensure fairness to other licence fee payers.

    Thank you again for contacting the BBC.

    • MrGrimNasty permalink
      October 11, 2022 11:31 am

      Reveals a lot about what is wrong with the BBC, out of control and not self aware.

  21. Vernon E permalink
    October 11, 2022 11:42 am

    I think that a lot of this debate about minutiae is missing the point. The public (in the broadest sense) is being distracted by much more sinister forces than the BBC (though they are a willing fellow traveller) and their like. The whole climate change pantomime is just a “flack-catcher” (to quote Tom Wolfe) to divert attention from the real intentions of Claus Schwab and the menof Davos and their Agenda 30. Just look at Holland as explained by Mark Steyn on GB News yesterday. Six hundred farms compulsively re-possessed by the government to make way for housing for immigerants and, in passing, to put an end to farming. We are all domed.

  22. October 11, 2022 11:55 am

    I think that the claim that CO2 persists in the atmosphere for 1000 years is incorrect.

    It is well established that approximately 50% of the yearly human emissions of CO2 caused by the burning of fossil fuels is reabsorbed each year (by the biosphere). If we stopped emitting CO2 from fossil fuel sources, the level of CO2 in the atmosphere would rapidly decline by the action of these CO2 sinks.

    • catweazle666 permalink
      October 11, 2022 2:01 pm

      “If we stopped emitting CO2 from fossil fuel sources, the level of CO2 in the atmosphere would rapidly decline by the action of these CO2 sinks.”

      In fact, if we ceased to emit it would make little or no difference to the CO2 level, as concentration would be maintained by release from the sinks – probably the ocean – to maintain the partial pressure of CO2 in accordance with Dalton’s law.

  23. Jules permalink
    October 11, 2022 2:07 pm

    The atmospheric atom bomb test ban in the 1960’s showed a measured sharp decline in radioactive carbon. It took a few years. It indicates that CO2 in does not persist for a 1000 years. The whole persistence of carbon and Britain owes the world a living for industrialising first arguments are fatally flawed.

  24. mikewaite permalink
    October 11, 2022 5:14 pm

    Russians having a bit of a snigger about the latest plans fron Ardenistan:

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