UC Scientist: Don’t Blame the Cows

Cody Sheehy is a rangeland ecologist and independent documentary producer.

87736822By Cody Sheehy

A couple of months ago, nearly lost amid the “Hopenhagen” hype,  the University of California, Davis (UCD) put out a press release with an admonition: “Don’t Blame Cows for Climate Change.” The release was a first look at some work conducted by UCD Associate Professor and Air Quality Specialist Frank Mitloehner. His study examines the greenhouse gases, or GHGs, emitted by the livestock sector.  As California’s air regulators turn more attention toward methane in particular, the report remains timely.

Mitloehner’s paper is entitled: “Clearing the Air: Livestock’s Contributions to Climate Change,” and was published in the peer-reviewed journal Advances in Agronomy. The paper is a synthesis of current science on the cattle-climate connection. Mitloehner has been updating some of that science in recent years.

In 2008, I stopped by his cluster of “bio bubbles;” airtight domes that serve as high-tech stables for cows. Inside, Mitloehner had set up simulated dairy operations, measuring GHGs emitted by the cows’ digestive process and decomposition of the manure. The numbers then in common use had been generated in the 1930s.

Research "bio-bubbles" at UC Davis. Photo: Cody Sheehy
Research "bio-bubbles" at UC Davis. Photo: Cody Sheehy

Mitloehner says cattle gets a bum rap in the media, and points to some examples, including a 2007 story in Time magazine, which included assertions like: “Which is responsible for more global warming: your BMW or your Big Mac? Believe it or not, it’s your Big Mac,” and “A 16-oz T-bone is like a hummer on a plate . . ”

In many cases, Mitloehner says the statements are crafted from an influnencial 2006 United Nations report entitled: “Livestock’s Long Shadow.”  According to the executive summary, “The livestock sector is a major player, responsible for 18 percent of greenhouse gas emissions measured in CO2 equivalent. This is a higher share than transport.”

But Mitloehner points to a quote deeper in the report:

“The respiration of livestock makes up only a very small part of the net release of carbon that can be attributed to the livestock sector. Much more is released indirectly by other channels, including: the burning of fossil fuel to produce mineral fertilizers used in feed production, methane release from the breakdown of fertilizers and from animal manure, land-use changes for feed production and for grazing, land degradation, fossil fuel use during feed and animal production and fossil fuel use in production and transport of processed and refrigerated animal products.”

Mitloehner cautions that the transportation number they use only accounts for tailpipe emissions. To be even-handed, he says, the authors should’ve incorporated emissions from the entire oil industry, including refinement of the oil and production of cars. In the UCD release, Mitloehner calls it a “lopsided ‘analysis” and “a classical apples-and-oranges analogy that truly confused the issue.”

Meanwhile, the Bio-bubbles have been generating some interesting numbers. Mitloehner found that the amount of methane the cows respire (belch) and how much is released in the breakdown of animal manure is quite different from what previous research had calculated. In combination, these two sources represent the most direct GHGs from the livestock industry, even if they’re not the largest GHG emitter associated with the industry. They’re also the most out of date.

Emission factors used in “Livestock’s Long Shadow” provide an estimate of methane respiration of about 86 million tonnes (metric tons) of methane (CH4) and 17.5 million tonnes of CH4 annually from manure decomposition. In the annex of the UN report, the authors write: “Obviously, great improvements to the estimates of emission factors could be made if more data on nutrition and production were available.” And so it is that inside his bio-bubbles, Mitloehner has come up with numbers much lower than those that represented the conventional wisdom since 1938.

All in all, we’ve got a discussion about comparing apples and oranges (more appealing than manure, granted) and some updated numbers that lower the emissions of livestock in one category. As with any scientific paper, there will probably be debate on both of these points and new ones, but let’s look at the broader consequences. Will industry look at this study and see an incentive to update and revise carbon emission numbers all across the board?

According to Emilo Laca, an agricultural ecologist at U. C. Davis, some of these questions will be fodder for policy debates that lie outside the realm of science. He says “The real question is, ‘How are we going to split this up?'” Laca used a hypothetical problem to explain: Let’s say that a certain livestock industry consumed 30% of soybean production as a food source. Livestock producers might concede that they should be accountable for 30% of carbon emissions related to soybeans. It makes sense. It’s what the numbers say. Others might counter that without this certain livestock industry, the soybean market would behave differently and some amount–lets guess 70%–wouldn’t need to be planted. Therefore, the livestock industry in this example is responsible for 70% of the emissions, not 30%. Science can support both interpretations. As Laca says, the decision is how to “split” things up. And ultimately, those decisions may fall to policy wonks.

UC Scientist: Don’t Blame the Cows 10 February,2010Craig Miller

19 thoughts on “UC Scientist: Don’t Blame the Cows”

  1. A fair comment and a useful footnote but to say that his research was “funded by the beef industry” is a distortion. The actual funding disclosure reads:
    “Since 2002, Mitloehner has received $5 million in research funding, with 5 percent of the total from agricultural commodities groups, such as beef producers.”
    It does appear that somebody’s math is a bit off, however. According to Mitloehner’s funding disclosure, most has come from government sources, with $500,000 from the Ag Air Research Council (livestock industry) and $40,000 from the National Pork Board (study of how ammonia fumes affect pigs). On my calculator, that works out to about 11%, not 5%. We could give UCD the benefit of the doubt; perhaps they referred to the portion of this particular study funded by ag interests.
    You can review the PDF funding disclosure here:

  2. Aha, I should read all the linked material first:

    This particular *paper* was funded by the beef industry (and specifically timed to affect the discussion in Copenhagen), although the research upon which it was based came from a variety of sources.

    That clarified, Mitloehner does seem to wax rather promotional in this passage from the press release:

    ‘”Smarter animal farming, not less farming, will equal less heat,” Mitloehner said. “Producing less meat and milk will only mean more hunger in poor countries.”‘

    I don’t see where the paper supports either of those points.

    This response to him includes some interesting specifics:

    ‘@Frank Mitloehner, I think you’re doing a bit of comparing apples to oranges. As you know, the FAO report considers a lot of sources of emissions that the US Greenhouse Gas Inventory does not — or at least it doesn’t allocated those sources to the Agriculture sector (sic)

    ‘A large part of the discrepancy involves how one chooses to allocate emissions. For example, the U.S. inventory’s section on agriculture does not include on-farm energy use, but the FAO report does. In fact the US inventory’s profile of the agriculture sector doesn’t include ANY carbon dioxide emissions. It focuses only on methane and nitrous oxide. On-farm energy use is covered in the Energy section of the inventory, and the impacts on carbon dioxide from land use changes (such as conversion of grassland to cultivated land) are covered in the Land Use, Land Use Change, and Forestry chapter. In contrast, FAO allocates all of these emissions to livestock production, and even considers transportation emissions.

    ‘Also, while net deforestation may not be occurring now in the United States, it’s not as if the land currently used for raising livestock was always thus. Much of it once was forest or grassland, and there’s a “cost” in terms of a foregone carbon sink that’s represented by that land.’

    Finally, this recent paper (and there seems to be a considerable body of related research) highlights the elephant in the room that Mitloehner seems to want to ignore (abstract):

    Public health benefits of strategies to reduce greenhouse-gas emissions: food and agriculture

    “Agricultural food production and agriculturally-related change in land use substantially contribute to greenhouse-gas emissions worldwide. Four-fifths of agricultural emissions arise from the livestock sector. Although livestock products are a source of some essential nutrients, they provide large amounts of saturated fat, which is a known risk factor for cardiovascular disease. We considered potential strategies for the agricultural sector to meet the target recommended by the UK Committee on Climate Change to reduce UK emissions from the concentrations recorded in 1990 by 80% by 2050, which would require a 50% reduction by 2030. With use of the UK as a case study, we identified that a combination of agricultural technological improvements and a 30% reduction in livestock production would be needed to meet this target; in the absence of good emissions data from Brazil, we assumed for illustrative purposes that the required reductions would be the same for our second case study in São Paulo city. We then used these data to model the potential benefits of reduced consumption of livestock products on the burden of ischaemic heart disease: disease burden would decrease by about 15% in the UK (equivalent to 2850 disability-adjusted life-years [DALYs] per million population in 1 year) and 16% in São Paulo city (equivalent to 2180 DALYs per million population in 1 year). Although likely to yield benefits to health, such a strategy will probably encounter cultural, political, and commercial resistance, and face technical challenges. Coordinated intersectoral action is needed across agricultural, nutritional, public health, and climate change communities worldwide to provide affordable, healthy, low-emission diets for all societies.”

  3. Fair enough–but you’re not allowed to raz Russ about the length of his comments anymore. 🙂

  4. Great comments.

    I found the hidden carbon costs of our beef production lands having been “deforested” in the past an especially interesting point. There is merit to this line of thinking in my opinion, but I want to offer a couple of nuances to consider. For example, in the Western US it’s common for our beef animals (non-dairy) to spend the majority of their lives on rangeland. From a resource perspective AND an environmental perspective, this is an important point. Beef cattle grazing naturally on rangelands don’t require modification of this ecosystem in significant way as it would say in Brazil. Common modifications would be to install watering points, put out mineral blocks, and upkeep of fencing. Beef cattle and existing wild ungulates such as elk coexist well and in some many cases research suggests that the grazing effects of cattle supplement or encourage the grazing done by wild animals. Also, GHG gases produced during this phase of production are much closer to what we expect from a “natural” system as I understand it. The manure is spread over a wide area, decomposes differently, and is beneficial for redistribution of nitrogen back into the grasses, etc. All in all, this “old technology” of letting animals raise themselves naturally has been proven sustainable over the past 10s of thousands of years. Our “natural” areas reflect and are dependent on the system I’m describing. Perhaps the most important thing is that these areas are protected from development and other very damaging uses as long as they remain viable profit generating rangelands. I think this is an important point to consider, so I’m going to say it another way. Rangelands out there are producing a product and a profit . . . that is way humans have not converted them to some other use like vacation homes . . . we need to be careful to not jump out of the frying pan and into the fire.

    So, in my mind, studies like Mitenloehner’s are best applied to the “brand new technology” of high intensity feedlot systems that produce our dairy cows and finish our beef animals and cause these animals to pollute some measurable amount of GHGs. The lots by definition do not occupy a large amount of land . . . but they do rely on large tracts of agricultural land for the commodity crops that feed our cows. Are the livestock responsible for detrimental effects of our agricultural crop lands? (I.e. past deforestation, irrigation, chemicals, as described in the blog response) I think Emilo Laca’s comments at the end of the blog speak to how complicated it is to “split” up these responsibilities. If beef cattle were not produced in the US (and we imported it) would it really be reasonable to assume those commodity crop farmers would replant trees on their extremely productive farmlands in the Midwest? Or would our market economy find a new use for those commodities?

    As for funding, we might be barking up the wrong tree with Mitenloehner. Having spent most of my career in the research world, it is my opinion and those of my colleagues that Mitenloehner ‘s study is one of those not compromised by the growing infusion of industry money into our scientific process. This is only my opinion, but I thought I pass it along. In general, I think skepticism in this vein is extremely healthy and needed into today’s spin environment because money IS coming in from those places. It’s a problem.

    Emilo Laca read the blog and wanted to clarify a couple of details. “I think that the blog confuses respiration and methane emission from cows. This will be counterproductive in long term. Cow respiration proper is negligible and involves CO2. Methane comes from rumen and concentrated manure (little air/manure ratio). They are far from trivial. LLS [Livestock’s Long Shadow] quote refers to respiration proper. Also, Frank’s CH4 numbers will probably be in the lowest end of the world spectrum because UC & Ca cows are best fed. Good feed=low CH4“

    Lastly, we should note that Mitenloehner started this research many years ago, long before Copenhagen was organized. It is true however, that his research is intended to influence the decision making process on these topics. I would suggest that the best applied research has an obligation to be pertinent to the decisions we need to make as a society. Therefore, I think another way to look at this paper is that is it commendable Mitenloehner took the time to write a synthesis paper like this one at a time when people need it the most.

  5. Its laughable you guys even bring up funding sources – honest you must be idiots to do that considering Mr Blooms funding/employment source, really.

    The entire subject is a joke – farting breathing cattle is too funny, kinda like saying Bloom expounds too much hot air so off with his head, which probably is closer to reallity.

  6. Well, Craig, is that the sort of comment you feel ought to be setting the tone for this blog?

    1. @Steve Bloom (and others please note): No it is not. Soon I’ll be doing a post that clarifies our guidelines for comments and in the future, comments that include personal attacks will be deleted. We provide this space for useful discussion, not as a venue for “food fights.”

  7. How about this funding – see any issues with this

    SCANDAL: Climate activists secretly on public payrolls
    They pop up everywhere on blogs, spouting their absolute belief in global warming and humanity’s central role in it, but now the London Telegraph has found taxpayer cash is being funnelled to pay for this seemingly citizen-driven propaganda ‘debate’:

    “More than £3.5 million (about NZ$9mil) has gone on recruiting a worldwide network of young “climate activists” in over 70 countries to engage in climate change propaganda – what Marxists used to call agitprop – and to pressure their politicians to join the worldwide struggle. Under a programme called Challenge Europe, £1.1 million has been paid out to fund young “climate advocates” in 17 countries across Europe, including Britain itself. But £2.5 million has been spent on a more ambitious project to recruit a global network of 100,000 activists in 60 countries across the world, led by 1,300 young “International Climate Champions”, to participate in “international peer networks, both in person and online, to share ideas, projects and experiences”.

    Strangely enough, this publicly undisclosed (in the sense your average climate activist doesn’t declare who’s yanking their chain most of the time) robbery of tax dollars to brainwash taxpayers is only the tip of the iceberg, because we already have evidence of similar schemes elsewhere, as I blogged several months ago:

    Continue reading “SCANDAL: Climate activists secretly on public payrolls” »

  8. Craig, I don’t think this (guidelinnes excerpt) —

    “NCPB reserves the right to delete any message under circumstances that, in NCPB’s judgment, are inappropriate, unlawful or otherwise detrimental to the community dialogue, such as the following:
    Personal attacks, hateful, racially or ethnically offensive or derogatory content, and harassment or threats against other participants of the discussion board, in the blog comments area or featured speakers on the site will not be tolerated. This includes libel or unsubstantiated accusations against another.”

    — needs any clarification whatsoever relative to Dixon’s previous post. Hopefully you’ll be removing the comment as soon as you get back.

  9. Steve,
    Thanks for your input and involvement. The community on the Climate Watch blog is generally a thoughtful, respectful one. It’s a rare case that we need to examine a comment this closely and consider removing it. In fact, to date, we haven’t deleted any non-spam comments, and we don’t take doing so lightly. We feel that the discussion here around this comment has been a useful one, and that deleting the comment at this point would devalue this important thread about what is appropriate conduct in this space. Now that the issue has been raised specifically, and in this very visible space, we hope and expect that future comments will adhere to the standards that most Climate Watch blog community members value and practice.

  10. So let me get this straight, Gretchen: You have a clear guideline but you’re ignoring it in order to leave an object lesson in view? Or, to put it another way, you’ll apply your clear guideline only going forward?

    Here’s the problem: The comment is libelous on its face. The problem with leaving it up is that someone might read it and think it’s true *because you’ve left it up*, your protestations to the contrary notwithstanding. If you’re worried about losing context, delete all the responses and discussion as well, and instead just put up a separate post reiterating the policy.

    To repeat, you have a clear policy that existed at the time the comment was made. Now apply it. Thank you in advance.

  11. Also, would a comment that included a similar libelous attack on you or Craig still be posted? I rather expect not.

    Finally, for the record, Craig promised me via separate email that it would be removed as soon as he got back. Have the two of you talked? I quote:

    “I am traveling and unable to delete it but it will be deleted. I wish I couldve gotten to it sooner because now it will look like favoritism. Pls give us a chance to get to these.”

    Please note that I don’t see any possible issue of favoritism (due to the crystal-clear comment policy). Dixon might in theory be upset for some other reason, but I rather suspect he’s quite used to having his flames censored elsewhere.

    1. For pity sakes Steve, all I did was point out that you attacked what appears to be a well done study about agriculture by questioning the funding from agricultural sources. Why you feel the need to attack the article to begin with is beyond me.
      Then I just pointed out you are a paid Enviromentl Activist, hardly libel but it is hypocritical on your part and thats all I said – so quit whining. By the way I’m not upset at all and have no axe to grind.

  12. OK Dixon, as long as this site has been transformed into “Libel ‘R’ Us,” exactly what is your information about my employment and funding? Time to put up or shut up (or more to the point, retract and apologize).

    Just for the record, in addition to the libel you violated the comment policy by a) calling myself and other “idiots” and b) saying “Bloom expounds too much hot air so off with his head, which probably is closer to reallity” (sic). In this where people crash planes into innocent people to make a political point about their taxes, it’s hard to know for sure that the latter isn’t an actual death threat.

    I’m really quite shocked that Craig and Gretchen seem to consider that sort of inflammatory rhetoric suitable for continued display on this site. Have they consulted with KQED’s attorneys about that?

    1. Let me try to bring some closure to this discussion with a few final remarks. The delay in doing so is because I’ve been on assignment and also because as this thread developed, it sparked an extensive internal discussion that included KQED’s social media working group, our News Director and Senior Online Editor.

      KQED is relatively new to the world of interactive commentary online. In crafting our guidelines we consulted with many news organizations that have more experience in this area and discussed internally the challenges we thought we would encounter in making this feature available. In the end, we crafted our guidelines to be as tolerant as possible in the interest of free speech. We recognize that this can be challenging and that there will be gray areas. And we anticipate that our guidelines will evolve over time, as they have in many journalism circles.

      We don’t see here a clear-cut violation of our guidelines for reader commentary. The comment that started this discussion was clearly not in the spirit of the Climate Watch community. In retrospect, however, my own impulse to delete it was premature and I take responsibility for that.

      In our guidelines, we “reserve the right” to delete inappropriate comments. That right is subject to editorial judgment. It doesn’t mean we’ll delete every comment to which someone takes offense. But there is a limit to what will be tolerated and the comment in question in my view came perilously close to that limit.

      I do hope we can move forward in a more collegial and respectful spirit, to continue this wide-ranging conversation that has, overall, been very productive, in my view. And, I hope we can acknowledge that there will be times when we can agree to disagree. Thanks for your participation and we will now close comments on this particular post.

Comments are closed.


Craig Miller

Craig is a former KQED Science editor, specializing in weather, climate, water & energy issues, with a little seismology thrown in just to shake things up. Prior to that, he launched and led the station's award-winning multimedia project, Climate Watch. Craig is also an accomplished writer/producer of television documentaries, with a focus on natural resource issues.

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