Do the math: There are too many cows!
By Paul Mahony /
Dec 20, 2013

Bill McKibben, founder of US-based climate change campaign group, recently visited Australia for a series of presentations and media appearances. McKibben appears to have been extremely effective in mobilising people around the world, who are demanding meaningful action on climate change. The group’s mission statement states that is “building a global grassroots movement to solve the climate crisis”.

In his 2009 book, “Storms of my Grandchildren“, the former head of NASA’s Goddard Institute for Space Studies, Dr James Hansen, described how the organisation’s name came about [1]:

“In 2007, the environmentalist and writer Bill McKibben began bugging me, very politely, to either confirm 450 parts per million as the appropriate target level of carbon dioxide in the atmosphere or else to define a more appropriate one. He was developing a Web site to draw attention to this target limit and was thinking of calling it”

Hansen eventually settled on a figure of 350. He and his colleagues explained the scientific basis for the number in a paper published in The Open Atmospheric Science Journal in 2008, titled “Target Atmospheric CO2: Where Should Humanity Aim?“. [2]

I attended McKibben’s Q&A session in Melbourne, and asked for his views on animal agriculture, given what I suggested were its massive impacts in relation to climate change.

McKibben’s main focus is fossil fuels, and I agree it’s essential that we deal with them. However, I also argue that we will not overcome climate change without a general move away from animal agriculture.

On the basis of McKibben’s response to my question and another question asked that day, along with the contents of his Orion Magazine article of 2 April, 2010 “The Only Way to Have a Cow“, I am concerned that he is dangerously under-estimating animal agriculture’s impact. [3]

Why do I use the word “dangerously”?

Firstly, because of the seriousness of the climate change crisis we are facing, which he understands very clearly.

Secondly, because McKibben has established a very large and loyal following, many of whom may readily accept what he says on most aspects of the issue.

The respect held for McKibben was epitomised by Melbourne academic, Robert Manne, at a presentation on the same day as the Q&A session. He told McKibben and the audience that there have been three names that stand out in the history of the climate movement: James Hansen; Al Gore; and Bill McKibben.

McKibben’s key focus in his responses and in the article were:

  • animal agriculture’s share of greenhouse gas emissions
  • factory farming
  • grazing practices
  • food miles

It seems that his position can be paraphrased as:

“If we want to reduce emissions from animal agriculture, we need to move away from factory farming, adopt a modified form of grazing, and buy locally.”

Let’s look at each of those issues.

1. Animal agriculture’s share of greenhouse gas emissions

1.1 Some Published Measures of Emissions: Goodland & Anhang and UN FAO’s “Livestock’s Long Shadow” Report

Purely as an example, I referred in my question to an article by Robert Goodland and Jeff Anhang in the November/December 2009 edition of World Watch Magazine, in which they estimated that livestock are responsible for around 51% of global greenhouse gas emissions. Goodland is a former lead environmental adviser to the World Bank, and Anhang is a research officer and environmental specialist at the World Bank’s International Finance Corporation. [4]

McKibben responded by refuting the suggestion of 51%, and saying that the correct figure is around 20%. He did not explain that view, but it may be based on the widely quoted estimate of 18% from the UN Food & Agriculture Organization’s (FAO) 2006 “Livestock’s Long Shadow” report. [5]

McKibben mentioned the 18% and 51% figures in his Orion Magazine article, referred to earlier.

In that article, McKibben stated that the “51%” study (presumably the Goodland and Anhang study but he provided no details) was “quickly discredited”. He did not support that claim with evidence.

Philanthropist and Microsoft co-founder, Bill Gates, seems to respect the Goodland and Anhang study, as he referred to it in calling for a move away from meat consumption in a “Mashable” blog post earlier this year. [6] Gates has also highlighted the issues on his own website. [7]

The FAO thought enough of the paper to invite Goodland to address its December, 2009 expert consultation on greenhouse gas emissions and mitigation potentials in the agriculture, forestry and fisheries sectors. [8]

Some may argue that the respiration issue (refer below) should not have been included by Goodland and Anhang. However, even if we were to remove that factor, the analysis would have indicated that livestock would be responsible for around 43% of emissions.

Goodland and Anhang highlighted many issues, which were reviewed in the context of “Livestock’s Long Shadow”. Two key issues were: (a) 20 year “global warming potential” (GWP) of methane; and (b) land use.

1.1.1 20-Year “Global Warming Potential” (GWP) of Methane:

If you’re not familiar with the GWP concept, you can find an explanation below. [9, 10, 11, 12] If you’d rather not read the details, the key point to note is that conventional measures of methane’s global warming impact measure it over a 100-year timeframe. However, methane breaks down in the atmosphere in around 12 years. That means the 100-year measure greatly understates its shorter-term impact, as it provides an average figure over a 100-year period, when the methane effectively did not exist during the final 88 years of that period.

Although methane may have a shorter life than carbon dioxide (which remains in the atmosphere for many hundreds of years), its impact can be long-term if it contributes to us reaching tipping points that result in positive feedback loops with potentially irreversible and catastrophic consequences. On the positive side, the relatively short-term nature of methane’s impact means that action on livestock production can be one of the most effective steps available to us in dealing with climate change.


The significance of methane in relation to livestock derives from the process of enteric fermentation, which causes the gas to be released through belching or burping. It is explained on the US Environment Protection Agency’s website [13]:

“Enteric fermentation is fermentation that takes place in the digestive systems of animals. In particular, ruminant animals (cattle, buffalo, sheep, goats, and camels) have a large ‘fore-stomach’ or rumen, within which microbial fermentation breaks down food into soluble products that can be utilized by the animal. Approximately 200 species and strains of microorganisms are present in the anaerobic rumen environment, although only a small portion, about 10 to 20 species, are believed to play an important role in ruminant digestion.  The microbial fermentation that occurs in the rumen enables ruminant animals to digest coarse plant material that monogastric animals cannot digest. Methane is produced in the rumen by bacteria as a by-product of the fermentation process. This CH4 is exhaled or belched by the animal and accounts for the majority of emissions from ruminants. Methane also is produced in the large intestines of ruminants and is expelled.”

The U.S. Environmental Protection Agency has reported, “Globally, ruminant livestock produce about 80 million metric tons of methane annually, accounting for about 28% of global methane emissions from human-related activities.” [14]

Here’s the trend in global methane emissions over the past few decades [15]:

Figure 1: Global methane emissions


1.1.2 Land Use

Another critical issue is land use, including foregone sequestration on land previously cleared.

The report highlighted the fact that “Livestock’s Long Shadow” did not allow for foregone sequestration on land cleared in the years prior to the reporting period, although Goodland and Anhang did not fully incorporate the impact of such foregone sequestration, as referred to below.

Australia’s National Greenhouse Inventory, like most international measures, also does not allow for such foregone sequestration in any of its emissions figures.

Goodland and Anhang suggest the possibility of allowing land that has been cleared for livestock grazing or feed crop production to regenerate as forest, thereby mitigating “as much as half (or even more) of anthropogenic GHGs” [greenhouse gases]. Such an approach is consistent with studies from the PBL Netherlands Environmental Assessment Agency and the Centre for Alternative Technology in Wales (responsible for the Zero Carbon Britain 2030 plan), referred to in my article “Prince Charles on Climate Change and Deforestation“. [16]

Goodland and Anhang suggest that the land could, alternatively, be used to grow crops for direct human consumption or crops that could be converted to biofuels, thereby reducing our reliance on coal. They have used the biofuel scenario in their calculations, allowing for the greenhouse gas emissions from the coal that is continuing to be used in lieu of the biofuels.

1.1.3 Other Issues

Other issues referred to in Goodland and Anhang’s report:

  • Livestock respiration overwhelming photosynthesis in absorbing carbon, due to the massive human-driven increase in livestock numbers.
  • Increased livestock production since 2002.
  • Corrections in documented under-counting.
  • More up to date emissions figures.
  • Corrections for use of Minnesota for source data.
  • Re-alignment of sectoral information.
  • Fluorocarbons for extended refrigeration.
  • Cooking at higher temperature and for longer periods.
  • Disposal of waste.
  • Production, distribution and disposal of by-products and packaging.
  • Carbon-intensive medical treatment of livestock-related illness.

1.2 Australian Emissions

For Australia, I reported in my article “Omissions of Emissions: A Critical Climate Change Issue” on the Department of Climate Change and Energy Efficiency’s figure of around 10% for animal agriculture’s share of emissions, comparing that to an estimate by campaign group Beyond Zero Emissions (BZE) of around 50%. [17] Additional factors considered by BZE relate to deforestation, grassland emissions and savanna burning, including the role of tropospheric ozone.

In that article, I argued that Australia’s official figures, in many respects, understate livestock’s true impact. The under-reporting has occurred because relevant factors are:

  • omitted entirely from official figures, e.g. tropospheric ozone;
  • classified under different headings, e.g. livestock-related land clearing reported under “land use, land use change and forestry” (LULUCF);
  • considered but with conservative calculations, e.g. methane’s impact based on a 100-year, rather than 20-year, “global warming potential” (as referred to above).

It is clear that many factors can be taken into account when measuring the climate change impact of different sectors. I believe McKibben is wrong to effectively ignore valid alternatives to conventional measures of livestock’s impact. Particularly in relation to methane, it is difficult to understand why he would ignore as critical factor as the 20-year global warming potential.

2. Grazing Practices

The second question at the Q&A session relating to animal agriculture referred to the March, 2013 TED presentation by Alan Savory, which was the subject of my article “Livestock and climate: Why Allan Savory is not a saviour“. [18]

In responding to my question, McKibben spoke favourably of Savory’s approach, and recommended that those at the session view the presentation.

I disagree with his views on that approach. In my view, Savory’s belief that we can achieve sustainable grazing practices on the scale needed to feed the masses is misguided. A move to such practices, along with a return to traditional farming practices and local food sourcing (referred to earlier), will not enable us to overcome catastrophic climate change, even if we also end our addiction to fossil fuels. (Information from James Hansen and colleagues on the critical role of reforestation can be found in section 2.6.)

Savory’s key claim is that livestock can be controlled through a planning process he called in the presentation “holistic management and planned grazing”, so as to be “a proxy for former herds and predators”, in trampling dry grass and leaving “dung, urine and litter or mulch”, enabling the soil to “absorb and hold rain, to store carbon, and to break down methane”.

He argues that we need to increase livestock production, rather than reduce it, in order to reverse desertification and overcome climate change.

In my “Savory is not a Saviour” article, I referred to (amongst other evidence) a study by Emma R.M. Archer of the University of Capetown, published in a 2004 edition of the Journal of Arid Environments, investigating the effect of commercial stock grazing practices on vegetation cover in an eastern Karoo study site in South Africa. Based on 14 years of satellite imaging data and objective assessment methods, the researchers reported that “holistic resource management” strategies of the type advocated by Savory resulted in lower levels of vegetation than more traditional approaches. [19]

I also referred to a study published in the journal Nature in 2005, indicating the massive potential for reforestation (as opposed to desertification) in Africa if livestock were removed and the related savanna burning ceased. [20]

McKibben’s comments at the presentation were consistent with those in his Orion Magazine article, in which he described a system that appeared to be Savory’s, although he did not provide a source for the information he presented.

Some key points in relation to these issues:

2.1 Animal Populations

McKibben indicated at the presentation and in the article that large numbers of ungulate animals (hoofed mammals) had not caused problems in the past.  He wrote:

” . . . long before humans had figured out the whole cow thing, nature had its own herds of hoofed ungulates. Big herds of big animals – perhaps 60 million bison ranging across North America, and maybe 100 million antelope. That’s considerably more than the number of cows now resident in these United States. . . . So why weren’t they filling the atmosphere with methane? Why wasn’t their manure giving off great quantities of atmosphere-altering gas? . . . These old-school ungulates weren’t all that different in their plumbing – they were methane factories with legs too.”

Those comparisons give an inaccurate indication of the overall animal biomass, partially because they take no account of the relative weight of the different animals or the related difference in methane emissions.  His suggestion that there were “big herds of big animals” is difficult to reconcile with the fact that the native pronghorn (the USA’s “antelope”) generally weigh around one-tenth as much as cows and bulls bred for beef (90 to 150 pounds for a pronghorn compared to an average of 1,277 pounds for beef cattle). [21, 22]

The pronghorn (Antilocapra americana) is not a true antelope but in a family by itself (Antilocapridae). [23, 24]

Pronghorns are among the fastest animals in North America. They can run at more than 53 miles (86 kilometres) per hour, and can travel for many miles at half that speed. [21] It’s difficult to imaging a 1,200 pound cow achieving that feat.


Pronghorn on the Horizon | © FletchPhotography | iStockphoto | Weighing around one-tenth of a cow bred for beef

McKibben’s comments may appeal intuitively, but they do not stand up to close scrutiny. This table compares the biomass of native species before European settlement with current North American livestock populations:

Table 1: Specified North American Animal Populations and Biomass


Here are the comparisons in another form:

Figure 2: Specified Animal Populations from Bill McKibben


Figure 3: North American Biomass of Ruminant Animals


Of course, methane, nitrous oxide, carbon dioxide and other greenhouse gases do not respect national borders. If we consider global (as opposed to North American) animal populations, the comparison is even more stark.

More than 3.5 billion cows, sheep, goats, camels, other camelids and buffalo (which are all ruminants) are now kept at any one time as livestock globally, which is around 22 times the number of North American bison and antelope in earlier times, as referred to by McKibben. In just the fifty years to 2011, the combined number of such animals increased globally by around 1.15 billion, which itself is around seven times the number of McKibben’s bison and antelope. [25]

Figure 4: Number of Specified Animals


I had referred in my article to researcher Geoff Russell in relation to the massive increase in the number of animals since the year 1500, due to manipulation of breeding habits. Russell has stated:

“Wildlife rates of conception, growth, and the like don’t match what can be achieved by artificial selection, artificial insemination, good fences, irrigated feed production, predator extermination and all the other paraphernalia of modern agriculture. These have produced a totally unnatural and unprecedented explosion in numbers of those animals which people have designated as livestock.”

Russell’s table comparing global numbers from the year 1500 with those from 2004 can be seen below. [26]

Figure 5: Growing dominance of livestock biomass


2.2 Methane absorption

In supporting Savory’s intensive grazing practices, McKibben says:

” . . . recent preliminary research indicates that methane-loving bacteria in healthy soils will sequester more of the gas in a day than cows supported by the same area will emit in a year.”

He is assuming that Savory’s approach will result in healthier soils than would otherwise exist. That claim is incorrect in relation to large-scale agriculture. However, the key problem with the statement is that the preliminary research on which it appears to have been based was subsequently found to be subject to a critical and massive error.

As with most of McKibben’s arguments in the Q&A session and his Orion Magazine article, no studies or research were cited. However, the comparison used, and the timing of the article, make it likely that it was based on the work of Professor Mark Adams and colleagues from the University of Sydney.

On 3 September, 2009, an article by Matt Cawood was published in “The Land” and “The Australian Dairy Farmer“. The article stated that the research of Adams and his colleagues found that certain “high country soils oxidise methane at a rate of . . . 8,760 kilograms per hectare per year. . . . By contrast, 100 head of cattle produce about 5,400 kg/ha of methane a year”. [27, 28]

On the basis of those figures, a hectare of land in the Snowy Mountain region of Australia could support 162 head of cattle and be methane neutral. That figure is derived by dividing the amount of methane said to be absorbed by a hectare of land (8,760kg) by the methane emissions per cow (54kg).  That is:

  • 8,760kg/54kg = 162

The research was subsequently reported by Adam Sacks on the US environmental website Grist on 31 January, 2010. [29]

Sacks wrote, ” . . . one cow’s worth of healthy land actually absorbs one hundred times the methane emitted by that cow in any given year”.

Sacks also wrote: “The current orthodoxy tells us that because of digestive methane emissions, raising animals for food is a global warming problem, not solution.  This is true given current practice: crowded feedlots with grain-fed, drugged cattle and manure lagoons on devastated lands, shipped long distances. “

That sounds very much like Bill McKibben (to repeat my paraphrase): “If we want to reduce emissions from animal agriculture, we need to move away from factory farming, adopt a modified form of grazing, and buy locally.”

In response to queries from Australian author and mathematician Geoff Russell (also referred to earlier), Sacks said that the source used for his article was an article in the Australian newspaper of 26 October, 2009, titled “A hiccup in the cow burp theory“. [30]

Sacks wrote, “A recent study points to oxidation of 8,760 kg per hectare per year – whereas a cow emits something in the neighborhood 54 kg per cow per year (i.e., 162 cows/hectare).”

Russell referred to the Grist and Australian articles in his article “Balancing carbon with smoke and mirrors” of 31 July, 2010 on the Brave New Climate website. He had been in touch with Professor Mark Adams, following which it seems the error in the calculations was discovered.

A figure in micrograms had mistakenly been represented as milligrams within the calculations, meaning that the original “preliminary research” had overstated the relevant land’s methane absorption rate by a factor of 1,000. The result was that the high country soil’s methane oxidisation rate was only 8.76 kg per hectare per year, rather than 8,760 kg.

That hectare of land would not support 162 cows in a carbon neutral manner, but 0.162 of a cow. That is:

  • 8.76kg/54kg = 0.162 (Corrected)

Matt Cawood reported the error in The Land on 16 July, 2010 [31]. He said, “Dr Robert Simpson, a post-doctoral research fellow who supplied the corrected values, said the methane oxidation rate measured by University researchers is actually 8.75 kilograms per hectare per year.”

The reference to a figure of 8,750kg in that article, compared to the original figure of 8,760kg, was not explained. However the difference is immaterial, and still generates a figure of 162 head of cattle per hectare.

Despite the error being discovered, the myth has lived on. As recently as 20th March, 2012, agricultural scientist Fiona Chambers said in a debate at a packed Melbourne Town Hall in Australia (commencing at around the 22 minute mark) [32]:

“Research undertaken recently at Sydney University has shown that just one hectare of pasture has enough potential for these methane-loving bacteria to actually extract methane out of the environment that could be produced by 162 head of cattle. Now that’s more than you could run on a hectare, so it makes it methane-neutral.”

The host organisation’s website confirms that Ms Chambers is a lecturer at Marcus Oldham Agricultural College in Geelong. She holds a Diploma of Applied Science in agriculture, specialising in animal health, nutrition and genetics and is undertaking a Master of Animal Breeding Management at Sydney University. [33]

At the end of the debate, the then Executive Director of climate change campaign group, Beyond Zero Emissions, Matthew Wright challenged Chambers on the veracity of the research by suggesting it had not been peer-reviewed. She confirmed that she had not seen a peer-reviewed journal article supporting the research. [34] However, the problems with the research went much further than Matthew Wright had indicated, as he did not refer to the massive over-statement of the soil’s methane absorbing capacity.

2.3 Manure Management

As referred to earlier, McKibben asked the following in relation to bison and antelope roaming across North America in earlier times:

“Why wasn’t their manure giving off great quantities of atmosphere-altering gas?”

Any soil’s supposed ability to absorb methane will have relatively little impact on overall greenhouse gas concentrations to the extent that those concentrations relate to gases emitted by manure. The first reason is that the amount of methane emitted by manure is very small compared to the amount emitted through enteric fermentation. For example, in Australia in 2011, emissions from manure management represented 3.9% of reported agricultural emissions, compared to enteric fermentation 65.1%. Methane represented just over half of the manure management emissions, with the balance being nitrous oxide. [35]

Emissions from agricultural soils (17.8%) and prescribed burning of savannas (12.3%) accounted for most of the remaining emissions. Animal agriculture has previously been reported to be responsible for nearly 60% of savanna-burning emissions. [36]

2.4 Fencing

McKibben suggests that the key technology in adopting alternative grazing practices is the single strand electric fence, for improved control of cattle. Here are some thoughts from Gerard Wedderburn-Bisshop on that issue from the TED website, in response to Allan Savory’s presentation:

“What Savory does not mention is that intensive (cell) grazing is only viable where water points are close and labour is cheap. Temporary or permanent fencing is labour intensive, moving herds daily requires far more labour input than most operations can afford.”

Wedderburn-Bisshop is a former Principal Scientist with the Queensland Government Department of Environment and Resources Management Remote Sensing Centre. He was responsible for assessing and monitoring vegetation cover, structure and trend across the state. This involved leading a team of remote sensing scientists to develop satellite monitoring methods to cover an area of 1.7 million square kilometres each year.  He is currently a Director and Lead Scientist with the World Preservation Foundation and a researcher on Beyond Zero Emission’s Land Use Plan as part of its ZCA2020 project.

2.5 Native Grasslands and Mimicking Natural Processes

McKibben talks of “old-school ungulates” continually moving in order to avoid predators. He has stated that the grasslands they grazed “covered places that don’t get much rain”, including Australia. However, Australia “is the only continent other than Antarctica to NOT have native hoofed animals”, so those “old-school ungulates” did not exist there in the timeframe being considered by McKibben. [37]

In any event, his suggestion of “mimicking those systems with cows” is verging on the absurd when one considers the massive discrepancy between animal populations in earlier times and livestock numbers now, as referred to it item 2.1.

2.6 The critical role of reforestation and soil carbon

If we are to have any chance of reaching McKibben’s 350 ppm target, then we must objectively and realistically address the issues of reforestation and soil carbon. The essential role of those factors in achieving the target is demonstrated in this image from Hansen’s “Target Atmospheric CO2: Where Should Humanity Aim?” paper.

Figure 6: CO2 Emissions and Atmospheric Concentration with Coal Phaseout by 2030


By the time the 350 ppm target could be achieved with action on land clearing and soil carbon (around 2090 based on IPCC’s estimates of oil and gas reserves and assuming an end to non-sequestered coal use by 2030), it would fall short at around 380 ppm if we were to ignore those factors. If we did so, then the target would not be achieved until well beyond 2150.

To rely on an approach lacking scientific credibility, such as Allan Savory’s, would be a grossly irresponsible step at this critical point in the history of climate change.

[Please see Note 3 below, being a postscript regarding additional articles commenting on Allan Savory's work.]

3. Factory Farming

In his Orion Magazine article, McKibben stated (with my bold highlights):

Industrial livestock production is essentially indefensible—ethically, ecologically, and otherwise. We now use an enormous percentage of our arable land to grow corn that we feed to cows who stand in feedlots and eructate until they are slaughtered . . . We should simply stop eating factory-farmed meat and the effects on climate change would be but one of the many benefits.”

He refers to feedlots, with cattle fed on corn, along with cattle standing still “in big western federal allotments overgrazing the same tender grass”, as factory farming. He seems to ignore the impact of traditional grazing (including the related enteric fermentation) and grazing-related land-clearing and soil emissions. Those factors are related to (amongst others) the gross and inherent inefficiency of animals as a food source. For example, we currently use far more land due to grazing (and feed crop production) than would be the case if plant nutrition was accessed directly, rather than via the digestive systems of animals.

In Australia, feedlots represent only a small percentage of the beef industry. According to the Australian Lot Feeders Association, “The Australian beef feedlot industry plays a complementary role to the larger extensive grass fed cattle sector given that feedlot cattle spend 85-90% of their lives in a pasture based environment.” [38]

Despite the relatively small role of feedlots, as mentioned earlier and in my “Omissions of Emissions” article, the livestock sector is estimated by Beyond Zero Emissions to be responsible for around 50% of Australia’s total greenhouse gas emissions. That figure is significant for a country that, even using more conservative estimates of livestock’s impact, vies with the United States for the highest per capita emissions among developed nations.

Even in the United States, beef industry feedlots are generally only used for the final 3-5 months of an animal’s typical 15-24 month lifespan.

It is important to note that cattle emit considerably more methane when consuming grass than when consuming grain. Professor Gidon Eshel of Bard College, Annandale-on-Hudson, New York has reported, “since grazing animals eat mostly cellulose-rich roughage while their feedlot counterparts eat mostly simple sugars whose digestion requires no rumination, the grazing animals emit two to four times as much methane”. [39]

In 2007, writing in the medical journal The Lancet, a team of international health experts led by Australian National University professor Tony McMichael warned that the world’s growing appetite for meat was increasing greenhouse gas emissions as (amongst other problems) vast areas of rainforest were bulldozed for grazing land.

In its article on the Lancet report, The Age newspaper in Melbourne provided the following estimated breakdown of livestock-related greenhouse gas emissions [40]:

  • Deforestation and desertification 35.4%
  • Manure 30.5%
  • Methane emissions, mainly burping 25.0%
  • Artificial fertilisers 3.4%
  • On-farm fossil fuel use 1.2%
  • Other 3.6%

4. Food Miles

At the Melbourne Q&A session, McKibben said that one of the most important measures for reducing the climate change impact of animal agriculture was to buy locally. He said that when he is home, he tries to eat nothing produced outside the valley in which he lives.

In his Orion Magazine article, he referred to “the truck exhaust from shipping cows hither and yon”.

Is his concern over transportation vindicated by the evidence?

A comprehensive study of the emissions intensity of different food products in Sweden was undertaken by Annika Carlsson-Kanyama and Alejandro Gonzalez in 2009, and published in The American Journal of Clinical Nutrition. [41] The study authors are from the Division of Industrial Ecology, Royal Institute of Technology, Stockholm, Sweden, and the Research Institute on Biodiversity and Environment (Inibioma-Conicet), Bariloche, Argentina respectively.

Emissions intensity represents the kilograms of greenhouse gas emissions per kilogram of product.

The study included a wide range of foods, including legumes, fruit and vegetables, commodities which are often overlooked in reports on  this subject. It  included CO2-e emissions  involved  in  farming,  transportation, processing, retailing, storage and preparation.

A key point from the study was that beef is the least climate efficient way to produce protein, less efficient than vegetables that are not recognised for their high protein content, such as green beans and carrots. Its emissions intensity (“Beef: domestic, fresh, cooked”) is 30, as shown in the following chart, which compares it to various other products:

Figure 7: Emissions Intensity of specified food products


As a comparison, in 2003, the Australian Greenhouse Office reported a figure of 51.7kg for beef [42]. That figure was based on carcass weight. As only around 55% of a carcass is used for meat, the figure for beef based on a kilogram of served meat at that time would have been approximately 94 kg. The level of livestock-related land clearing has since reduced. Taking those factors into account, the Carbon Neutral group in Perth, Western Australia, has more recently estimated an emissions intensity figure for beef of 30.9.

Further comparisons are as follows, along with beef for ease of reference (with reference numbers in brackets):

Wheat and other grains: 0.4 [42]
Fruit and vegetables: 0.48855 [43]
Potatoes (Domestic, cooked): 0.45 [41]
Rice (Cooked): 1.3 [41]
Soy beans (Transported by boat and cooked): 0.92 [41]
Beef (Domestic, fresh, cooked): 30 [41]

So what is the contribution of transport to a product’s greenhouse gas emissions? Here’s what Carlsson-Kanyama and Gonzalez said on that matter:

“ . . .  to obtain emissions at Swedish household consumption level, the emissions from transport, packing, storage, retailing, and cooking are added considering their corresponding losses in the food chain. For example, land and sea transport accounts for 0.32 kg CO2/kg soy when transport overseas is included.”

The transportation component will be determined generally by weight, so its contribution should be the same for a kilogram of beef as for a kilogram of soy. In this case, unlike soy, there appears to be no sea transport involved in the beef figure. In the absence of a more precise figure, let’s assume that beef’s transport-related emissions per kilogram of product are the same as those of soy, even though they are likely to be less.

On that basis, of beef’s 30kg of emissions, around 0.32kg (1.1%) comes from transportation.

Figure 8: Beef’s emissions intensity including transportation (kg)


Air transportation adds considerably to the emissions intensity of a product, but that was not a factor in the beef referred to in the Swedish study. The following extracts deal with that issue, and add further light on the extremely favourable results for plant products.

“For vegetables and fruits, emissions usually are less than or equal to 2.5 kg CO2 equivalents/kg product, even if there is a high degree of processing and substantial transportation. Products transported by plane are an exception because emissions may be as large as for certain meats.”

“Emissions from foods rich in carbohydrates, such as potatoes, pasta, and wheat, are less than 1.1 kg/kg edible food.”

“Plant foods based on vegetables, cereals, and legumes present the lowest GHG [greenhouse gas] emissions with the exception of those transported by airplanes.”

“Animal products, including dairy, are associated with higher GHG emissions than plant-based products, with the highest emissions occurring in meats from ruminants.”

On the basis of these findings, McKibben’s concerns over transportation are ill-founded relative to what seems to be a lack of concern over certain other aspects of animal agriculture’s impact.

Another Issue: Health

McKibben said in his Orion Magazine article: “Oh, and grass-fed beef is apparently much better for you – full of Omega 3s, like sardines that moo.”

Whether it comes from grass-fed or grain-fed cows, beef is responsible for serious health problems. My article “If you think it’s healthy to eat animals, perhaps you should think again” reported on the links between consumption of animals and cancer, heart disease, diabetes and other ailments, as documented by the likes of Harvard University, Cornell University, The World Cancer Research Fund and The National Cancer Institute. Red meat featured prominently in the findings. [44]


Without focussing on animal agriculture in addition to fossil fuels and other contributors to climate change, we will not overcome the crisis that we have created. Bill McKibben, like other prominent climate change campaigners, must not ignore what may be the most inconvenient truth of all.


1. None of the information in this article is intended to represent health, medical, dietary, nutritional or similar advice.

2. Bill McKibben’s tour of Australia was part of his “Do the Math” campaign. For Australian audiences, the local term “Maths” was used.

3. Postscript 14th August, 2013: Two additional articles commenting on Allan Savory’s work have come from Robert Goodland (referred to above) and James McWilliams. Goodland’s article is “Meat, Lies & Videotape (a Deeply Flawed TED Talk)” from Planetsave, 26th March, 2013, while McWilliams has written “All Sizzle and No Steak: Why Allan Savory’s TED talk about how cattle can reverse global warming is dead wrong“, published on Slate, 22nd April, 2013. Included in the McWilliams article are these comments about algal growth and desertification, a key aspect of Savory’s TED presentation: “Further weakening Savory’s argument for the wholesale application of holistic management to the world’s deserts is his distorted view of desert ecology. There are two basic kinds of deserts: genuinely degraded landscapes in need of revival and ecologically thriving ones best left alone. Proof that Savory fails to grasp this basic distinction comes when, during his talk, he calls desert algae crust (aka “cryptobiotic crust”) a “cancer of desertification” that represses grasses and precipitate runoff.  The thing is desert algae crust, as desert ecologists will attest, is no cancer. Instead, it’s the lush hallmark of what Ralph Maughan, director of the Western Watersheds Project, calls ‘a complete and ancient ecosystem‘. According to the U.S. Geological Survey, ‘Crusts generally cover all soil spaces not occupied by green plants. In many areas, they comprise over 70 percent of the living ground cover and are key in reducing erosion, increasing water retention, and increasing soil fertility’. Savory, whose idea of a healthy ecosystem is one with plenty of grass to feed cattle, neglects the less obvious flora – such as, in addition to algae crust, blackbrush, agaves, and creosote – that cattle tend to trample, thereby reducing the desert’s natural ability to sequester carbon on its own terms. ‘It is very important,’ Maughan writes, ‘that this carbon storage not be squandered trying to produce livestock.’”


Blog Author: Paul Mahony (also on Twitter, Slideshare and Sribd).

Note: This article first appeared on the author’s Terrastendo blogging site on 26th July, 2013.

Main Image: Poppy and Jarrah hold a 350 kick-board at the Great Barrier Reef |

Footnote re Main Image: Increasing CO2 concentrations are adversely affecting coral reefs due to warming ocean temperatures and ocean acidification. Cattle grazing is also affecting the Great Barrier Reef off Queensland, Australia.

The journal Water Science and Technology has reported on the impact of run-off from areas used for cattle grazing to the Great Barrier Reef Marine Park (GBRMP) [45]:

“Grazing of cattle for beef production is the largest single land use on the catchment with cropping, mainly of sugarcane, and  urban/residential development considerably less in areal extent. Beef cattle numbers are approximately 4,500,000, with the highest stock numbers in the Fitzroy catchment.”

“Beef grazing on the large, dry catchments adjacent to the GBRMP (in particular the Burdekin and Fitzroy catchments) has involved extensive tree clearance and over-grazing during drought conditions. As a result, widespread soil erosion and the export of the eroded material into the GBR has occurred, and is continuing.”


[1] Hansen, J. “Storms of my Grandchildren”, Bloomsbury, 2009, p. 140,

[2] Hansen, J; Sato, M; Kharecha, P; Beerling, D; Berner, R; Masson-Delmotte, V; Pagani, M; Raymo, M; Royer, D.L.; and Zachos, J.C. “Target Atmospheric CO2: Where Should Humanity Aim?”, 2008.

[3] McKibben, Bill, “The only way to have a cow”, Orion Magazine, Mar/Apr 2010,

[4] Goodland, R & Anhang, J, “Livestock and Climate Change – What if the key actors in climate change are cows, pigs, and chickens?”, World Watch, Nov/Dec, 2009, pp 10-19, /pdf/Livestock%20and%20Climate%20Change.pdf

[5] Food and Agriculture Organization of the United Nations, 2006 “Livestock’s Long Shadow – Environmental Issues and Concerns”, Rome

[6] Gates, Bill, “Food is Ripe for Innovation”, Mashable, 22 Mar 2013,

[7] Gate, Bill, “The Future of Food”, The Gates Notes, undated,

[8] Goodland, R., “Forests, Fisheries, Agriculture: A Vision for Sustainability”, presented to UN FAO Expert consultation on greenhouse gas emissions and mitigation potentials in the agriculture, forestry and fisheries sectors, 2-4 Dec 2009,

[9] IPCC, TS.2.5 Net Global Radiative Forcing, Global Warming Potentials and Patterns of Forcing,

[10] FAO Newsroom, “Livestock a major threat to environment”, 29 November, 2006,

[11] Sanderson, K, “Aerosols make methane more potent”, Nature, Published online 29 October 2009, doi:10.1038/news.2009.1049;

[12] Enteric Fermentation – Greenhouse Gases,

[13] Schindell, D.T.; Faluvegi, G.; Koch, D.M.; Schmidt, G.A.; Unger, N.; Bauer, S.E. “Improved Attribution of Climate Forcing to Emissions”, Science, 30 October 2009; Vol. 326 no. 5953 pp. 716-718; DOI: 10.1126/science.1174760,

[14] U.S. Environmental Protection Agency, “Ruminant Livestock”,

[15] National Oceanic and Atmospheric Administration, “The NOAA Annual Greenhouse Gas Index (AGGI)”, updated summer 2012,

[16] Mahony, P., “Prince Charles on Climate Change and Deforestation”, Terrastendo, 11 May 2013,

[17] Mahony, P., “Omissions of Emissions: A Critical Climate Change Issue”, Terrastendo, 9 Feb, 2013,

[18] Mahony, P., “Livestock and climate: Why Allan Savory is not a saviour”, 26 Mar, 2013,

[19] Archer, E.R.M., Journal of Arid Environments, Volume 57, Issue 3, May 2004, Pages 381–408, Beyond the ‘climate versus grazing’ impasse: using remote sensing to investigate the effects of grazing system choice on vegetation cover in the eastern Karoo“,

[20] Mahesh Sankaran, Niall P. Hanan, Robert J. Scholes, Jayashree Ratnam, David J. Augustine, Brian S. Cade, Jacques Gignoux, Steven I. Higgins, Xavier Le Roux, Fulco Ludwig, Jonas Ardo, Feetham Banyikwa, Andries Bronn, Gabriela Bucini, Kelly K. Caylor, Michael B. Coughenour, Alioune Diouf, Wellington Ekaya, Christie J. Feral, Edmund C. February, Peter G. H. Frost, Pierre Hiernaux, Halszka Hrabar, Kristine L. Metzger, Herbert H. T. Prins, Susan Ringrose, William Sea, Jörg Tews, Jeff Worden1 & Nick Zambatis, “Determinants of woody cover in African savannas”, Nature 438, 846-849 (8 December 2005) | doi:10.1038/nature04070; Received 26 April 2005; Accepted 22 July 2005,

[21] National Geographic,

[22] National Cattlemen’s Beef Association, Beef Industry Statistics, Nov 2012,

[23] The Internet Center for Wildlife Damage Management,

[24] Desert USA: Pronghorn,


[26] Russel, G. Forget the quality, it’s the 700 million tonnes which counts, 17 Nov 2009,, citing Subak, S., GEC-1994-06 : Methane from the House of Tudor and the Ming Dynasty, CSERGE Working Paper, and Thorpe, A. Enteric fermentation and ruminant eructation: the role (and control?) of methane in the climate change debate, Climatic Change, April 2009, Volume 93, Issue 3-4, pp 407-431,

[27] Cawood, M., “ETS lifeline: soils capable of absorbing cattle methane”, The Land, 3 Sep 2009,

[28] Cawood, M., “ETS lifeline: soils capable of absorbing cattle methane”, The Australian Dairy Farmer, 3 Sep 2009,

[29] Sacks, A., “The Climate Solution: Got Cows?”, Grist, 31 Jan, 2010,

[30] Parkinson, G., “A hiccup in the cow burp theory”, The Australian, 26 Oct 2009,

[31] Cawood, M, “Error in Snowy Soils Carbon Report”, The Land, 16 July, 2010,

[32] The Wheeler Centre,  Intelligence Squared Debates: Animals should be off the menu, Video,

[33] Intelligence Squared Debates: Animals should be off the menu,

[34] Youtube video “Fiona Chambers from the meat industry gets busted – The Real Truth At Last”,

[35] Australian Government, Department of Industry, Innovation, Climate Change, Science, Research and Tertiary Eduction, “Australian National Greenhouse Accounts: National Inventory Report 2011, Vol. 1″, p. 213 incl. Table 6.1,

[36] George Wilkenfeld & Associates Pty Ltd and Energy Strategies, National Greenhouse Gas Inventory 1990, 1995, 1999, End Use Allocation of Emissions Report to the Australian Greenhouse Office, 2003, Volume 1″, Table 5.2, p. 83.

[37] Araucaria Ecotours, Wildlife of Australia,

[38] Australian Lot Feeders Association, “The Australian Cattle Feedlot Industry”, undated,

[39] Eshel, G., “Grass-fed beef packs a punch to environment”, Reuters Environment Forum, 8 Apr 2010,

[40] Minchin, Liz, “Oblivious to the impact of our carnivorous ways”, The Age, 13 September, 2007, Australia/New Zealand Reference Centre, ISSN: 0312-6307, Accession No. SYD-5GIJTTK2FQCG0SC2GSK and (Table not included in the web link.)

[41] Carlsson-Kanyama, A. & Gonzalez, A.D. “Potential Contributions of Food Consumption Patterns to Climate Change”, The American Journal of Clinical Nutrition, Vol. 89, No. 5, pp. 1704S-1709S, May 2009,

[42] George Wilkenfeld & Associates Pty Ltd and Energy Strategies, National Greenhouse Gas Inventory 1990, 1995, 1999, End Use Allocation of Emissions Report to the Australian Greenhouse Office, 2003 (Table S5, p. vii)

[43] Carbon Neutral Ltd,

[44] Mahony, P., “If you think it’s healthy to eat animals, perhaps you should think again”, Terrastendo, 12 February, 2013,

[45] J. Brodie, C. Christie, M. Devlin, D. Haynes, S. Morris, M. Ramsay, J. Waterhouse and H. Yorkston, “Catchment management and the Great Barrier Reef”, pp. 203 & 205, Water Science and Technology Vol 43 No 9 pp 203–211 © IWA Publishing 200,

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