Emissions GR Impacts

Livestock and Climate Change … Status update

Guest Post by Geoff RussellGeoff is a mathematician and computer programmer and is a member of Animal Liberation SA. His recently published book is CSIRO Perfidy.

The United Nations report Livestock’s Long Shadow (LLS) came out in 2006 with an estimate that 18 percent of anthropogenic greenhouse gas emissions are attributable to livestock. If you exclude deforestation emissions, then the number drops to 14 percent. Some 95 percent of these emissions are direct emissions of methane or nitrous oxide with just 5 percent being from associated energy use as shown in the table which is a contraction of a table from LLS.

Livestock Greenhouse Giga Tonnes
Emissions CO2-eq
Energy Related 0.16
Methane 2.20
Nitrous Oxide 2.20

The reason the energy emissions are so small is that almost no processing is included. The energy associated with the refrigerated meat chain from abattoir to consumer, cooking costs, energy to build the trucks that carry the animals and later the meat etc. None of this was included.

A couple of years after the LLS report, BNC published a piece by myself, Barry Brook and Peter Singer which showed that Australia’s most powerful climate forcing was livestock and not coal fired power stations. The demonstration relied on the difference between radiative forcing, a concept roughly equivalent to warming and used by climate scientists, and the less accurate concept of carbon dioxide equivalent used in the Kyoto protocol.

Two years later and it’s time for an update. The NOAA chart shows that methane levels are rising again after a flat spot during the early 2000s, and the biggest single source of anthropogenic methane is livestock.

This update will look at implications of livestock growth predictions, the Goodland/Anhang photosynthesis imbalance theory, industry attempts to show beef is carbon friendly, and ruminant methane reduction research. I’d like to also cover black carbon and ozone issues, but that will have to wait. I have written a small section to explain why black carbon and ozone are really, really important, but the detail will have to wait.

Pelletier and Tyedmers PNAS paper

August 2010 saw the publication in the US Proceedings of the National Academy of Science (PNAS) of a paper looking at the implications of various livestock population scenarios out to 2050. It looked at the impact of the scenarios on postulated safe operating limits for three things:

  1. human production of greenhouse gases,
  2. our use of planetary biomass
  3. and our production of reactive nitrogen.

These are all topics which will be familiar to some degree from earlier BNC posts (here for biomass, and here for nitrogen).

Currently the greenhouse gas emissions (CO2eq) for every person on the planet average about 4.8 tonnes a year. Australians are among the worst with emissions more than 5 times this. Nuclear powered France comes in at a little less than double the average. Typically, developing countries are below average emitters. For example Bangladesh emits about 0.9 tonnes per person per year. Sub-Saharan Africa comes in closer to average at around 4.5 with half that coming from land-use change … burning the landscape.

By 2050, the global average needs to be about 1. That’s right, just 1 tonne of CO2eq for each of the 8.9 billion people that P&T expect on the planet. That’s no change for Bangladesh and a 25 fold reduction for us.

P&T consider several scenarios:

  1. No change in livestock populations or emissions. Since 95 percent of livestock emissions are direct rather than from energy use, a rebuilding of our energy infrastructures can’t make a dent in livestock emissions. So livestock, assuming no growth at all, will occupy about half of that 8.9 billion tonnes of CO2eq, leaving half a tonne per annum for everything else. Because this scenario postulates no increase in livestock but a growing population, the average consumption of meat per person must fall.
  2. Growth in livestock as per FAO predictions. In this case livestock emissions will be 71 percent of each person’s allocated tonne of CO2eq.
  3. The vegan. This is one of two endpoint scenarios. I’ve called it a vegan scenario, P&T call it their soy scenario because they assumed that all protein comes from soy and none from animal products. Soy protein to go for 8.9 billion can be generated for a greenhouse gas cost of just 0.1 tonne of CO2eq per person. Of course, it’s not necessary to eat soy to get protein. Protein is actually tough to avoid and humans don’t need much compared with, for example, goats.
  4. Extreme meat. In this scenario P&T look at what happens when animal products supply all of a person’s protein requirements. They view this as the opposite endpoint of the vegan case, but it’s already happening in many first world countries. Australians, for example, average 73 grams of protein a day from animal products, which means all the rest of the food they eat contributes superfluous protein. In such a scenario, 92 percent of your tonne of CO2eq will come from the animal products in your diet. There won’t be much room left in your allocated tonne for anything else. As a footnote, I should say that P&T are using very low emission factors for their beef, so I’d say many Australians are already well over their tonne just from their meat alone.
  5. Chicken substitution. This interesting scenario postulates that all livestock increases above the year 2000 level required to meet the demands of the extra 2050 population will come from chicken which has the lowest greenhouse gas footprint of any meat. Under this scenario, livestock consumes 62 percent of a person’s 1 tonne allocation.

An LLS reply …

The P&T paper prompted a response from FAO’s LLS authors Steinfeld and Gerber who argued that changes are already in place to make meat more environmentally friendly … by making it more animal abusive with a shift to pigs and chickens. It was a qualitative reply to a set of quantitative predictions.

Steinfeld’s use of the word “shift” is vague and a little misleading. The global cattle population has increased in each of the past four decades. True, it hasn’t grown as fast as pigs and chickens, but this doesn’t mean that there has been any global substitution of pigs and chickens for cattle. Pigs have long been the dominant meat globally with pig and chicken meat production combined being triple the size of beef. Without a reduction in cattle, and there is no evidence of this globally, it’s difficult to envisage any significant decrease in overall livestock impacts in the 3 areas P&T consider. Steinfeld’s response is really no more than hand-waving.

Is “abusive” a defensible description of the pig and chicken industries? Absolutely and it has solid scientific support. A major study looking at chickens in the UK found that only a few percent can walk normally. The researchers looked at 51,000 birds in 206 flocks. Apart from the few percent walking normally, the rest suffered varying degrees of crippling because their muscle growth exceeds that of their skeletal system. Scientists have also shown that the birds are in pain. They will quickly learn to select drinking water laced with analgesic when given a choice. This is a heavily globalised industry so there are good reasons to believe this study is representative. The situation with pigs is little better … typically 60 percent of breeding sows are replaced each year with lameness being a common reason.

P&T on Biomass

P&T use an estimate of the maximum sustainable limit on human biomass use by 2050 of about 9.7 billion tonnes annually which is consistent with a a land use stabilisation scenario of the IPCC. Livestock already use about 7 billion tonnes of biomass. But far more critical is which 7 billion. Almost 3 billion of those 7 are crop residues. This increases erosion and damages soil structure, ultimately reducing the productive capacity of plants which provides the bulk (83 percent) of human food. In wealthy countries we compensate with more fertiliser, but in poorer countries low productivity and hunger are the result. It’s tough to decide which of the livestock industries’ devastating impacts on animals, people and the planet is worse … animal suffering, species extinction, bowel cancer or methane’s contribution to climate change. But exacerbation of hunger and poverty in poor countries by the apparently innocuous process of eating crop residues possibly trumps all four.

Worldwatch and mega fauna

In 2009 Worldwatch published a paper by Robert Goodland and Jeff Anhang which put livestock emissions at 51 percent of anthropogenic emissions. I’ve mentioned this before. A large part of the difference between the 18 percent and 51 percent figures comes down to the treatment of livestock respiration … the carbon dioxide breathed out by animals (and us). If livestock are gradually reducing planetary plant capital, then at least some of their respiratory CO2 should counted. Current IPCC accounting rules are predicated on an assumption that respired carbon is matched (or exceeded) by plant growth.

Measuring such matters is difficult at best, but an interesting study came out in 2010 which throws light on the issue from a different angle. Put simply, the study estimated that humans and their domesticated biomass black holes … livestock … are consuming about 6 times more plant matter than the long extinct mega-herbivores in their hey-day back in the Pleistocene. This makes it clear just how unprecedented our current impact on the planet is, regardless of how the detail pans out.

Carbon neutral cattle stations

The last few years have seen a number of studies trying to show that various grazing systems are carbon friendly. This one from Mark Liebig at the US Department of Agriculture is an example and contains references to quite a few more. Here’s an Australian one from the Queensland Department of Primary Industries and Fisheries.

I’ve dealt with these issues in some detail before. But here’s an executive summary.

The first fundamental problem is in how the system boundary is defined. Consider methane. We used to have a planet with a rough balance between the methane sources and sinks. The terrestrial sources were things like wetlands and there were also terrestrial methane sinks like forests and some grasslands some of the time. The terrestrial sinks were always significant but were about a third the size of the atmospheric sinks. Regardless of the relative size of the sinks, it seems pretty obvious that you just can’t run around finding methane sinks and sticking cattle on them to make the area “methane neutral”. Ditto carbon in general. This is as silly as drawing a system boundary around a rechargeable plug-in electric vehicle and calling it pollution free.

The other standout issue is that of alternatives. A long term study in South East Spain illustrates the kinds of gains in carbon sequestration that can be made in suitable areas when pastures are converted to woodland.

These are not subtle points and when groups of well trained and intelligent scientists do substantial studies involving plenty of time, money and equipment and forget to mention these issues in the subsequent paper, then you have to wonder if the work is politically rather than scientifically motivated. In the case of the Queensland study mentioned above, Principal Scientist Gerard Bisshop resigned from the Queensland Government in protest.

Is Queenland a developing country hunting CDM credits?

It’s interesting to compare the Queenland study with appropriate United Nations Framework Convention on Climate Change Clean Development Mechanism (CDM) rules. These are the rules which developing countries need to follow in order to get tradeable carbon offset credits for reforestation work on agricultural or pastoral land. The rules are clear and require that the land is degraded and degrading with crops or livestock numbers having declined by at least 30 percent or more during the five years preceding the project. i.e., an ongoing cattle (or wheat) property can’t get credits for woody regrowth because it happened to decide not to bulldoze one or more paddocks. But the above linked Queensland DPI paper claims credit for precisely this kind of non-activity. It wouldn’t qualify for actual tradeable credits for a developing country under CDM and it shouldn’t appear in dodgy pro-industry advocacy papers by Queensland Government scientists.

And the CFI? … Carbon Farming Initiative

The Australian Government has recently released its Carbon Farming Initiative (CFI) with a consultation paper and draft legislation for public comment. Despite the draft legislation being 331 pages of very precise legal language, the real substance is still being developed in Methodology documents being developed “with industry”. I’ll try and describe its key features as the substance emerges in a future post.

Less methane per moo

I feel compelled to give an update on the scientific progress to feed or engineer ruminants to produce less methane. Stories about breakthroughs in this area appear about as regularly as brain dead suggestions that eating more kangaroos will save the planet. Here’s a research result that might prompt just such a breakthrough story:

Many members of a series of … [compounds] were potent inhibitors of methanogenesis by rumen contents in vitro. The most potent compound inhibited methane production by 70% or more at a concentration of 1 microgram/ml (approximately 2.5 mumol/l).

Sound good? A massive 70 percent reduction in methane …

Yes it’s in vitro, but that’s a minor issue, think of the 70 percent!

This quote comes from a piece of research almost 30 years ago. Livestock farmers have long considered methane production from an animal as wasted energy and scientists have been working on a solution to this “problem” for a very long time. I traced papers back to the 1980s before losing patience. Apart from a huge wad of basic science about rumen function, I found papers on all kinds of things people have added to sheep or cattle feed to reduce methane production. The list included: mustard oil, horseradish oil, glucosinolate, cashew nut oil, linseed oil, coconut oil, krabok oil, palm fronds, soy oil, whole soybeans, antibiotics (various), fumaric acid, canola oil, copra meal, monolaurin, bromochloromethane, monensin, Yucca schidigera, Quillaja saponaria … and these are just the things with common names rather than chemical formulas. Monensin deserves a little footnote … it’s from a group of chemicals called ionophores, some of which have antibiotic properties. Meat companies are using ionophores as growth promoters while still using “raised without antibiotics” labels. One news story about huge US chicken producer Tysons doing this is here, but, curiously, the original Associated Press source seems to have been pulled from the website.

Many of the compounds reduce methane emissions but none seems to have made it into active use for all kinds of practical reasons. Seriously, who would waste cashews on cattle? A further persistant problem is that the organism populations in rumens adapt and can make any impacts short lived. Antibiotics work to some degree but create an evolutionary arms race in the rumen which will eventually see resistant organisms emerge. We don’t need any more antibiotic resistant bugs on the planet.

Apart from adding things to ruminant feed, the other approach under research is artificial selection. Some animals eat less per kilogram of growth and thereby generate less methane. Breed from these animals and hopefully the offspring will be similar. It’s rather trickier than it sounds and the gains will be small. How small?

Genetic approaches

Back in 2006 an Australian study did modelling suggesting that breeding for low methane production might yield a cumulative reduction in methane emissions in the Australian herd by 3.1 percent by 2025. This is hardly earth shattering, but seems to be enough to secure funding for this approach.

Since then various genes have been isolated that are associated with feed use efficiency (which is linked to methane production) with one study finding that these genes account for about 6.9 percent of the variability and a 2010 study found 150 gene factors (SNPs for those who know about such things) that account for 36 percent of the variability. How do you breed herds with these factors? That’s a good question.

As I was reading these papers it wasn’t always clear what was happening over time in the same animal. A group of Swiss researchers seemed to have the same interest. They examined animals from 3 popular dairy breeds over 41 weeks and found plenty of variability at different times but very consistent long term averages. They concluded:

The apparent lack of persistence of individual animal differences in methane yields suggests that genetic determination of this trait is of minor importance in dairy cows.

Measuring methane

recent news article raised the issue of the accuracy of measurements of methane from cattle. The researcher involved was Canadian PhD student Jennifer Ellis. She has published a couple of papers, one of which I have, but she hasn’t (yet) responded to email requests, so I don’t have the other. The news article states:

Statistics have been giving us a bum steer when they state how much cattle methane emissions contribute to global warming, a new study shows. That’s because mathematical equations used to predict cows’ methane emissions are inaccurate and don’t take into account factors such as dietary changes, said Jennifer Ellis, lead author of the study and a PhD student at the University of Guelph.

The paper of Ellis’s that I do have investigates the accuracy of various equations used to predict methane from cattle. The first step is to look at the accuracy of the various methods of measuring methane from actual animals … there are three. Ellis and her 12 co-authors are happy that all three methods give the same results. So there isn’t a problem measuring methane emissions from cattle. But of course, you can’t measure emissions from every animal. You need to use the measurements on some animals to come up with equations which predict national herd emissions on the basis of livestock genetics and lifestyle. Is it true, as the article implies, that after 30 years of work, nobody has fitted any half reasonable models to the data?

In a 2008 paper, Ellis’s Ph.D supervisor, Associate Professor Ermias Kebreab calculated that current IPCC equations overestimate the emissions from US dairy cattle by about 12.5 percent and underestimate the emissions from US feedlot beef animals by about 9 percent. Since the ratio of beef to dairy cattle is probably about 10 to 1 then, the equations will give a net underestimate of total cattle emissions in any place with US feedlot conditions … and cattle emissions dominate livestock emissions. So the equations may be off by a few percent, but hardly enough to warrant the bum steer claim, especially since they look to be underestimating cattle methane.

But getting back to Ellis and her paper that I do have. She tested a swag of different equations proposed by many different researchers against a database of actual measurements from animals. Here’s a couple of her pictures to give you an indication of the findings. Each little diamond is a single animal. The graph below is from one equation and you can see from the predominance of diamonds below the observed=predicted line, that this equation underestimates emissions.

The equation used in the next figure on the right looks reasonably balanced.

It’s superficially clear that the range of emissions from various animals is large and not well captured by the available equations which are all pretty simple linear combinations of dietary components that researchers suspect are important. The equations were probably popped out of some linear regression software. But all you really need for large scale use is reasonable symmetry about the observed=predicted line. On the other hand for individual animals, the equations are frequently off by large amounts … factors of 2 or more. This indicates that it’s likely that nobody really has a clue about what causes the extreme variability between animals and that the dietary components featuring in the equations may not be among the causal factors driving that variability. The list of causal factors included in the equations includes starch, cellulose, forage, nonfiber carbohydrate, fat, dry matter intake and lignin. These are all common agricultural science suspects. There isn’t a single vitamin in the list or any of the other myriad suspects that feature in human nutritional work. My non-expert judgement is that this research, despite being decades old, is still in the very early stages. Make no mistake, I’m not maligning the scientists. This is very tough science, a ruminant is a wondrously complex creature and the research effort is tiny compared to, for example research into the diseases caused by red meat … like bowel cancer … or heart disease.

Industry responses

The livestock industry has countered LLS with all manner of rubbish. For example the NSW Farmer’s Association ran a line which confused US figures with global figures and left out nitrous oxide emissions altogether. Much of this confusion comes from one Frank Mitloehner who has been trumpetting a 3 percent figure at any journalist who will listen for some time now. While I’m sure Associate Professor Mitloehner knows what he’s talking about, journalists and NSW Farmer’s Association people tend to be easily confused.

Livestock methane emissions in the US are indeed about 3 percent of US emissions and are well below the 14 percent global average figure of LLS … about half of which was nitrous oxide as we saw in the first table.

It is common for US authors to confuse the US with the entire planet, but US livestock methane emissions are below average for a number of unsurprising reasons:

  1. US cattle are predominantly grain fed (producing less methane) than cattle on pasture.
  2. The US ratio of cattle to people is about 1 to 3 compared to 1 to 1 in Brazil and well above 1 to 1 in Australia.
  3. US methane emissions from garbage are huge. In Australia, by comparison, and we are not noted for frugality, our garbage methane emissions are 1/6th of our livestock emissions. In the US, methane from garbage exceeds livestock methane.
  4. The US imports about 10 percent (net) of its beef and almost all of its sheep meat … not that they eat much. So the emissions from that beef don’t appear in US figures.
  5. Lastly, US advertisers and fast food chains may portray their home country as a hamburger culture, but Americans actually eat twice as much chicken as beef and almost no sheep meat at all. Australian ruminant meat intake is double that of the US.

It’s not so much that US livestock emissions are small, but that they are swamped by other profligate consumption emissions.

Tropospheric ozone and black carbon

Some readers will have seen the Supreme Master TV ads (on SBS in Australia) which proclaim that “If we cut methane emissions now, the worst climate change effects could go in a decade.”. The Supreme Master organisation has some of the look and feel of a religious sect to an athiest like me, but its backbone seems to be a large group of dedicated, caring and sharing volunteers who are refreshingly easy to deal with. I haven’t seen data to back their claim but here’s a claim from a paper co-authored by one of the world’s top climate scientists. Veerabhadran Ramanathan is Distinguished Professor of Climate and Atmospheric Sciences at the Scripps Institute of Oceanography at the University of California. Here’s the quote:

Fully applying existing emissions-control technologies could cut black carbon emissions by about 50 percent. And that would be enough to offset the warming effects of one to two decades worth of carbon dioxide emissions. Reducing the human-caused ozone in the lower atmosphere by about 50 percent, which could be possible through existing technologies, would offset about another decade’s worth. Within weeks, the heating effect of black carbon would lessen; within months, so, too, would the greenhouse effect of ozone. Within ten years, the earth’s overall warming trend would slow down, as would the retreat of sea ice and glaciers.

The detail will have to wait, but ending animal agriculture would be a big contribution to the reductions of both black carbon and ozone because the main cause of rising tropospheric ozone is rising methane and livestock is also a potent producer of black carbon via deforestation. The bottom line is that the Supreme Master claim is definitely plausible if Ramanathan’s modelling is accurate.

Concluding remarks

Livestock’s Long Shadow marks a watershed with livestock industry advocates giving solid numbers for many of livestock’s worst environmental impacts. The numbers were conservative as the subsequent Goodland/Anhang figures indicated. The report was also solid in its demonstration that more meat and dairy products requires more intensification if environmental impacts are to be minimised. Intensification is the industry’s euphemism for confinement, chemicals, crippling and suffering. The only way for meat and dairy to reduce its costs on the environment is to increase its cost on animals. For meat to become greener while continuing to be produced in vast quantities requires that it become crueller.

A population’s various impacts on the planet are largely dominated by what it eats. As people get richer, they can swamp this impact with other things. Private jets and a couple of Hummers will blow any environmental footprint budget. But for most of the planet’s 9 billion people in 2050, it will be food choices that dominate their impacts on the planet and it’s pretty clear that change is required. More of the same is both undesirable for most of the creatures involved and probably impossible. We need a substantive dietary transformation. The changes will be small in Bangladesh but large in Australia and other extreme-meat countries. As omnivores, unspecialised eaters, we have choices. We can trash the planet with our food choices, we can allow pigs, chickens and cattle to outbid the poor for food, or not.

Appendix … P&T figure with food supply characterists

P&T contained some fancy graphics which confused me a little … so I’ve tried to redraw, in the figure above, some of the data in what I think is a clearer form and added a heap detail about the global food supply … sticking to the law of conservation of confusion which allows the additon of extra data while keeping confusion constant :) I haven’t (yet) included nitrogen data. The data in the figure are generally the latest I could find, but the percentages of meat from different systems are ratios from LLS (circa 2000) and applied to the 268 million total meat production in 2007. The biomass data come from Kraussman. If you look at the red lines from “Meat” to “2796 Calories”, you will see it is about 8 percent of global calories. The other 8 percent, not highlighted with any lines, is dairy and eggs.


By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

61 replies on “Livestock and Climate Change … Status update”

That’s it we are going to have to turn to insects for protein production, would be more effective and consume fewer resources than vertebrate protein. Insects have attractive qualities for food production besides their high energy efficiency. For example the spatial usage and water requirements are only a fraction of that required to produce the same mass of food with cattle farming. Production of 150g of grasshopper meat requires less than a liter of water, while cattle requires 3290 liters to produce the same amount of beef.


Can you provide a link to this study Geoff?

…an interesting study came out in 2010 which throws light on the issue from a different angle. Put simply, the study estimated that humans and their domesticated biomass black holes … livestock … are consuming about 6 times more plant matter than the long extinct mega-herbivores in their hey-day back in the Pleistocene

Thanks for the comprehensive overview. While I don’t think that ending animal agriculture entirely is either feasible or a good idea, there obviously needs to be dietry transformation in terms of the total amount of animal products consumed. I’m really not sure how this can be achieved in the face of millions of dollars being spent in advertising to boost consumption or green meat “facts”.

(that advertising campaign occured around the same time as the “Can red meat be green?” debate that was travelling to universities around the country. NB: it wasn’t a debate.

It seems though that at least some in the industry see the writing on the wall – this study concluded that “few options exist to reduce methane emissions from extensive grazing systems without reducing beef production” (funded by MLA)


Megan: Sorry I should have linked that study:

Thanks for the links … particularly the Rolfe link.
Meat now is where tobacco was in 1964 … the evidence is in, all that is required is for the science
to get adequate attention. Tobacco bought scientists just like MLA does and the end of the tobacco industry was considered unthinkable
for a long time. We still import tobacco but the industry is gone.


A cultural problem with returning pasture to woodland is the perception that it is a wasted opportunity. That may not be the case when tractor diesel, NG derived urea and concentrated phosphates are barely affordable. Nutrient recycling and farming effort will need to be more localised and labour intensive. Smaller amounts of animal protein may need to be blended with vegetable fillers eg in burgers.

Today my travelling companion wanted a lunch of grain fed chicken which I went along with. We also saw backpackers harvesting raspberry crops for upmarket retailers and export. However both grain feeding of animals and exotic fruits may be luxuries in the future. The dominant crops may be pulses and root vegetables which will be grown and consumed by locals. Human wastes may have to be returned to that crop. Animals may be valued as much for their ability to convert weeds to manure as for protein. Grain feeding and animal confinement will be reduced.

We’ll all be fitter and healthier and there will be less GHGs. I’m not saying this as some kind of greenie utopian. The facts are that oil is 50% depleted, economic phosphate is 70% depleted and gas has maybe 20 good years left during which time there will be many millions more mouths to feed.

Observation; nuclear supporters clearly now include some vegans and off-grid survivalists. That must make many nuclear opponents look like wimps.


DV8 – I’m not sure if you’re being serious or facetious!

Dead serious.

Entomophagy—the consumption of insects—has been around for thousands of years in some cultures, it is estimated that more than half the people of the world eat a variety of insects on a regular bases.

In Thailand, open-air markets sell silkworms, grasshoppers, and water bugs by the pound. Movie theaters in South America sell roasted insect as snacks instead of popcorn, ( I have eaten both in quantity, and enjoyed them) and Japanese supermarkets stock their shelves with aquatic insect larvae.

While insects are high in protein and relatively low in fat, they are also a “clean” food source because many feed-off of fresh plants. Additionally, they are not scavengers, as is the more commonly eaten shellfish. Insects are also easy to raise, and to harvest, and they are highly nutritious to eat. For example, a termite contains approximately 14 grams of protein and 36mg of iron. In comparison, lean beef contains 27 grams of protein and only 4mg of iron.

And it is not that they have to be eaten as is. Red worms can be processed very simply into an analog of lean ground beef that in a hamburger, is indistinguishable, on the palate, to the real thing.


I wonder how accurate it is to imply that the recent upward trend in global methane emissions is due to livestock.

Recently it has become apparent that the oil and gas industry has been leaking far more methane as they produce oil and gas than they have ever admitted in the past. The EPA is in the process of redoing their reference document on methane leakage, which was used by the IPCC. See:

Also, warming in northern regions of the planet is suspected of increasing methane release there.

Dr. Euan Nisbet makes the point that until it becomes possible to measure actual emissions rather than calculate what they are thought to be, the possibilities for error are immense. He is published in Science, June 4 2010 “Top Down Versus Bottom Up”. He seems to think that measuring methane and deciding where it actually came from will be possible in the next few years.

That said, this is an interesting issue you are discussing. Thanks for the post.


Maybe it’s only me that finds “Statistics have been giving us a bum steer ” in the context of cattle methane emissions amusing… I truly hope it was deliberate.


Sure,there are many ways to tackle the problem of human impact on Planet Earth.Dare I suggest that the most fundamental and important one is to reduce the human population.But,as you said in a previous comment Geoff,that is a no brainer so you won’t address it.

Good luck with changing human diets in any sort of a meaningful time frame relative to climate change..Social behaviour is notoriously sticky.Also,likening diet to tobacco is disingenuous.The campaign against tobacco is based on major health concerns,not only for the user but for passive smokers.In case you haven’t noticed that campaign is a long way from being finished,even in Australia.

By the way,Geoff,you failed to mention the impact of pets in Australia.I haven’t seen too many vegan cats and dogs.
But that issue is a little too close to home for Animal Libbers.


david: The renewed rise in methane certainly isn’t due to livestock, but livestock is the biggest and one of the two sources we can easily do something about. Leaking natural gas being the other.

podargus: I know personally plenty of vegan dogs … because I know plenty of vegans. Dogs are omnivores, so making them vegan is easy. Vegan cats are more
difficult. There are suitable vegan foods for cats, but not all cats will eat them.

I can assure you that vegans discuss such issues
ad nauseum. We don’t ignore them at all. Hell, we even discuss the environmental and ethical implications of whether the chocolate on the top
of a soy chino is vegan and fair trade.


dv82xl: I’m guessing insects aren’t (very) sentient so I
have no ethical issues with eating them … or killing them when they eat my veggies. Other vegans think differently. But we can easily feed 9 billion without insects so they aren’t strictly necessary but they may be useful. Scientifically, the issue of pain in such creatures is open … they certainly have some of the
requisite physiology.

Have you got a link for
that red worm steak?


Geoff & DV8,

When we get good wet seasons like at present I find myself covered in leeches each morning.
A neighbour supplied the following recipe:

Yes, take two dozen leaches, sautee them with chopped onion, add herbs and spices of your choice. Mash it all up and put it in a sausage skin and serve it up to your guests as blood pudding! Eee by gum, it’s good!

Not sure how that would affect the ACO2 budget.


I have a cookbook that was written in the 1970s, called Entertaining with Insects, which gives instructions on how to clean and prepare earthworms for human consumption.

However I had these hamburgers at Montreal’s Insectarium several years ago at the restaurant they had there at the time. My personal favorite tho is silkworm grubs, just after the silk has been removed, fried in glee and garlic. Anyone who likes shrimp should like these too.


Snails are delicious, also witchety grubs. We have an earthworm that is over a meter long and when I see a Kookaburra pulling one out of the ground I’m tempted to chase him in the interests of carbon sequestration [and breakfast].
Another delicacy I collect each morning is when, after walking miles of fire trails, to protect myself from spiders in my beard I twirl a frond of lantana. Eventually I end up with a stick of fairy floss with spider sprinkles.
Would have to be nutritious if not delicious.



You don’t seem to support kangaroo meat consumption?
I’ve always found it to be not only the best meat in the world in all respects but when kangaroos can outbreed just about every form of domestic livestock without being domesticated and live in severely drought stricken country without degrading it anywhere near as much as those same domestics, they are surely more sustainable.

Killing them, done by gun and spotlight is also more humane.


I’m not sure I could come at eating insects, however rational it might be. Perhaps it’s just a cultural thing.

Since spirulina, soy, grains, seed and nuts are entirely adequate, I would prefer to stick with them.

Disclosure: I consume free range eggs and organic and biodynamic dairy and no-rennet cheeses. I’d miss these things, but would live with giving them up or perhaps having them as a very occasional food to be consumed 2-3 times per year.


kangaroos and spangled drongo: Kangaroos meat isn’t efficient and it isn’t humane (unless you think starving joeys is humane) and it causes bowel cancer like all red meat … possibly worse because it has more heme iron. There are good reasons why we produce so
little kangaroo meat and why we can’t eat the little we do produce … but have to export it all over the planet constantly finding new markets because repeat business isn’t good. I’ve just done
two largish pieces here:

and some macropod scientists have recently released a couple of reports here:


The bottom line on efficiency for people not inclined to read the longer posts and reports is that you only get 1.5 kg of prime quality fresh meat from a kangaroo. Maybe
another 1.5 second quality meat and 7-12 kg of
processed meat. With a 250 kg cattle carcase processed for burgers, it is almost entirely fresh meat. Processed meat is far more carcinogenic
than fresh meat … by about a factor of 3 per 100g.
If you process a cattle carcase as cuts, then you get maybe 70% of the carcase as fresh meat and the rest goes into biofuel. Do 100 kangaroos do
more or less damage than 1 cow?



Recommending an animal lib site for a balanced discussion on eating animals is like asking animal libbers for an objective view in muelsing.
There is a good and logical argument for both thos practices but you would never know listening to animal libbers.

Returning to a more “sustainable” lifestyle always requires more personal energy output from human beings and to cope with that, meat supplement is a very desirable part of the required diet. It can be the difference between success and failure.

Not many people these days have been in a situation where an extra mouthful of suitable sustenance got them over the line but they did not so long ago and that’s why they chose the meat option.



According to the UN’s Intergovernmental Panel on Climate Change, the greenhouse forcing from man made greenhouse gases is already about 86% of what one expects from a doubling of CO2 (with about half coming from methane, nitrous oxide, freons and ozone), and alarming predictions depend on models for which the sensitivity to a doubling for CO2 is greater than 2C which implies that we should already have seen much more warming than we have seen thus far, even if all the warming we have seen so far were due to man.

Just relax, Plan B will attend to it.


Spangled Drongo, your conclusion is erroneous because it hinges on an implicit assumption that the response time of global temperature to GHG forcing is zero (or close to it). If it is non-zero, then we should have expected less than the expected equilibrium warming. There are many attributes of the climate system that influence response time and make it >0 (theoretical minimum) – ocean heat absorption to depth, albedo surface changes, ice-water phase transitions, GHG release from natural reservoirs, etc.

On insect consumption (actually, non-crustacean arthropod eating more generally), I’ve never tried it myself, but I have done tours of various Asian markets, including one in the centre of Beijing, in which almost every conceivable taxa is on sale, including beetles, spiders, scorpions, skewered centipedes, etc. For some reason, it didn’t peak my appetite. I think I’d rather go the vego route (though I’m not there yet – by a long shot).

Geoff – how do carnivores reduce their natural cancer rates? Is cancer more prevalent, all else being equal, in vertebrate carnivores (e.g. lions, wolves etc.) compared to herbivores?


You generally make so much sense I will have to take your comments on insects seriously.

However, my gag reflex seems to be winning at this moment.


SD, heat sinks such as the ocean, and long response times. The CO2 does its business over decades and centuries.

Geoff, a problem with reading anything into the mortality rates of wild lion populations is that most are severely inbred – this includes the Serengeti population – and this would be the overriding effect. I was thinking more of zoo populations, for which we have good records and relatively controlled environments – if signals can be extracted anywhere, it would be from these records.


spangledDrongo: Animal Lib sites are as variable
as sites run by people who eat animals. I’ve seen
some appalling bias in, for example, the February
Science special edition on Food Security. Sloppy
beyond belief. But I don’t smear all scientists for
the sins of a few.

Barry: Short answer … I don’t know, but I’d be surprised if anybody has good data on this. I’ve seen some of the Serengeti studies on lions and they are doing well just to count the population. They
rarely know why animals die … except when there is a big die-off (e.g., canine distemper virus killed a third of the lions in 1994) …[goes to pubmed]

see page 5 in this

Click to access ehp0110-000285.pdf

which shows horses and cattle with way fewer cancers than dogs, cats, people and belugas!
I haven’t looked at the source of this data.



As usual, an interesting post. I do not attempt to take issue with your main conclusions with respect to global warming issues.

However, I continue to take exception to your description of intensive pig and poultry farming as abusive, though I think it could be applied to some instances of free range poultry farming in temperate climates. As a one time research veterinarian, I was heavily involved in and published on the subject of locomotor problems of meat chickens. The methodology underlying trials involving voluntary analegesic consumption to assume suffering are, in my view, extremely questionable and, in any event, demonstrate nociception if they demonstrate anything. You also questioned sentience in insects. Nociceptive responses can easily be demonstrated in locusts. Animal welfarists have taken such responses as evidence of insect suffering. They generally fail to point out that they can be demonstrated as easily in beheaded as in intact insects. In other words, evidence of pain behaviour in non human species is not necessarily evidence of conscious pain suffering. This is an anthropomorphic assumption based upon our uniquely human ability to empathise. Validation of such an assumption requires the demonstration of brain structures necessary to make such an explanation possible. Recent advances in neuroscience are placing more and more doubts on the existence of any such structures or mechanisms even in non primate mammals. Welfare scientists, however, who use certain behaviours as a proxies for suffering, rarely involve themselves with such niceties because they are in the business of proving that other species are just like us.


Insects, in theory, sound plausible as sources of protein. Having retired from the university, I started a business, now expanded by my son, which involves insect breeding. We produce several million crickets and locusts/week. It may be that we are very inefficient. However, we would have been bankrupt a long time ago if we had had to sell insects at broiler prices (on a weight eqivalent basis). Harvesting wild surpluses might supplement protein in certain places, but I can’t see large scale insect culture becoming mainstream for very many years, if at all. Also, having been exposed to various of our sauted insects at staff barbecues, I can’t say I’m sorry.


Douglas Wise – Insects already are a significant source of protein in the diets of many in the Third World. In as much as one of the recurring themes in this forum is the need to find ways to raise the global standard of living without destroying the environment, (or resorting to widespread genocide) and there is obviously less squeamish cultures that have no problem with the consumption of insects, this should be considered as an alternative to cattle as a source of meat.

While I think that there are things like silkworm grubs that would suit the Western palate as is, I am mostly interested in using insects as a feedstock for meat analogs.


Barry: Yes, you might get reasonable data from zoo
populations, and I’ll have a look some time. Your question is interesting in its own right, but I fear some people will also think it relevant to our diet.



I am assuming that, for insects to replace birds and mammals as protein sources, one would need to consider intensive production.

Conventional intensive livestock production requires that disease be controlled. This is achieved essentially by three means; a) hygiene/ isolation/single age sites etc, b) vaccination against a wide range of diseases, c) prophylactic drug use for specific diseases such as coccidiosis where a) and b) won’t work.

Some insect species can be heavily stocked, but there are upper limits to group size and the individual animals are very small. Insects moult and those of equal age don’t necessarily moult simultaneously. Thus, cannibalism can become a very serious issue. In consequence, labour inputs/unit weight of protein produced tend to be high. Furthermore, insects have immune systems that differ from those in mammals and birds. As far as I am aware, disease specific vaccination is impossible. There is a bewildering range of insect pathogens and there are few, if any, insect pathologists who study how to reduce the impact of diseases on their hosts. In fact, they devote their lives to a study of germ warfare against insects.

The fact that certain third world citizens make good use of insects such as flying ants and mopane worms at certain times of the year is not entirely relevant to the question of substituting insects for cattle.

If one thinks of locusts/grasshoppers, one needs to supply green food and one needs to feed at least twice a day. Dumping too much food into a unit in one go plays hell with humidity and hence insect thermoregulation and liveability. Each group feeds intensively for periods of days and then a few days go by with much lower feed intakes due to the majority moulting and not feeding. Thus, human attention is needed and militates against automation.

Our crickets require diets high in protein (similar to those of broiler chicks). Thus, Geoff’s point that it would be more efficient to feed humans direct with this diet rather than push it through animals becomes valid.

However, if you wish to persevere with the insect approach, perhaps you should encourage more wild harvesting. Suggest to the maasai that they give up their cattle (which provide them blood, milk and a bride price) and give them butterfly nets for catching grasshoppers – there are plenty out there at the moment. However, numbers might decline due to heavy exploitation and bush encroachment subsequent to cattle removal.

I think we’re getting off topic. I felt I had to respond since I’ve benefitted frequently in the past from your expertise. I thought I’d try and reciprocate.


Douglas Wise – I am not suggesting that insect husbandry for meat is anywhere near the level it is for other animals. Probably because the current demand can be managed by gathering from wild stock. However mealworms, silkworms, and earthworms, (note to pendents: I know the latter are not insects) are raised commercially in great numbers, as are bees, and have been for centuries. This suggests that this technology is not out of reach.

While I agree that in cases where conversion is not efficient that this would not be appropriate, there are areas where it is, and given concerns about the bearing capacity of land to support cattle, I still think that this path deserves consideration. Particularly in cultures without the European culture’s knee-jerk prejudice against it.


Douglas rightly raises a few scaling issues with insects. Plenty of things are easy until you try to scale them up. But he and most other people are wrong in thinking we need a “protein source”. Protein is ubiquitous. It’s only recently that people have been able to get enough calories while simultaneously being short on protein.


(note to pendents {pedants}: I know the latter are not insects)


FTR: pendants for those articles of jewellery {AusE/BrE} jewelry {AmE}.


It is interesting to consider that when cattle are lot fed and thereby assist with CO2 sequestration through soil improvement, erosion and siltation prevention etc, they are villified for their extra emissions.
Maybe we could breed edible insects to consume these trapped emissions [a la dung beetle] in a large building that housed the cattle.
[I wonder which would taste worse]


Manure is the bedding of choice for culturing Vermi already, although the valuable product here is castings, sold as vermicompost which is popular for fertilizing in ‘organic’ farming.

I’m a bit astonished that people automatically assume that edible insets are foul tasting, they are not. Mind you when grab a handful of the beetles that are deep fried and served like popcorn in Central American cinemas out of a wide-mouth box, the remaining contents shift in a disturbingly animated way, and this is a bit startling at first, but the taste is very nice.


You have been to some really interesting places:

“On insect consumption (actually, non-crustacean arthropod eating more generally), I’ve never tried it myself, but I have done tours of various Asian markets, including one in the centre of Beijing, in which almost every conceivable taxa is on sale, including beetles, spiders, scorpions, skewered centipedes, etc. ”

I am so relieved that none of this “peaked” your interest.


Down here in Florida we raise crickets as fodder for zoo animals. Right now we have a major crisis owing to a virus that is shutting down the major producers.


This thread has degenerated to nonsense.That is not surprising as the article itself is nonsense in the sense that it was written by a person who can’t see the wood for the trees.

By the way,is it true that mathematicians have a strong tendency towards autism?


So,Fran,which part of my comment was fact free?

If it is the first part then a close examination of the article and its predecessor might support my opinion depending,of course,on your own prejudices and I admit to not being free of prejudices.

If it is the second part then I suggest that you do some research on mathematicians and Aspergers Syndrome.

What I have tried to get across to Geoff Russell in my other (more polite) comments is that a one eyed enthusiasts approach to the many faceted problems of climate change is not a useful way of going about it. If I have to use a sledge hammer to crack a nut then so be it.


podargus: your (more polite) comments consisted of
noticing that we haven’t finished getting rid of smoking and a criticism that I didn’t mention pets … suggesting this was because of my animal lib affiliations.

I didn’t respond to the smoking issue but pointed out
that vegans do indeed consider the impact of their
pets … it’s non-vegans who (generally) don’t
think about either
their own food impacts or their pets.

I’m not sure if I should be flattered or insulted by the aspergers comment … perhaps I’d be a better
mathematician if I were more autistic. I’ll try and
do better in future!


Yet again,Mr Russsell,you are cherry picking the issues raised which you choose to address,even then in an inadequate fashion.

This is another indicator of a one track mind.What personality traits you have that would account for that is unknown to me and I couldn’t care less.

The fundamental fact is that you are a propagandist for an extremist organization – namely,Animal Liberation.This is more than enough for you to be fully discounted as a useful contributor to a climate change debate.In that sense you are in same boat as climate change deniers.


Podargus, your comments to Geoff are completely unconstructive. I’m no Animal Liberation “propagandist”, but I can see merit to much (most?) of what Geoff points out in his posts on BNC.

If you’re going to accuse someone of being an unuseful contributor to the climate change mitigation debate, at least do it by disputing the numbers and statements in the article.

The point is, broadly, that eating large quantities of meat generally results in significant GHG emissions. It also happens to have many other impacts on the environment, affects our health, and, to some, is an unethical way of viewing fellow species. Do you dispute this?


Here’s a question – given that methane has a nominal lifetime in the atmosphere of about 10 years before it’s oxidised to CO2 & water, and that the carbon those cows emit as methane came from atmospheric CO2 in the first place, aren’t longer-term livestock greenhouse impacts due entirely to ancillary energy use? (i.e. fertiliser for grain-fed cattle, transport, processing & refrigeration, etc)



Before CH4 is oxidised, it has a radiative forcing about 25 times that of CO2. So the primary greenhouse influence from livestock is CH4.

Also, the carbon they end up emitting as CH4 comes from what they eat, not from what they breathe. If much of the land livestock currently occupy was reverted to forest (or whatever type of land it originally was), the carbon storage potential would be far higher.



There were no facts anywhere in your post, so your challenge contains a logical error — it’s syntactically correct but returns no values.

The problem is that really what you want to claim is that we should not listen to Geoff because he’s a mathematician, mathematicians are often autistic and this explains his inability to “see the wood for the trees” (i.e. to address broader questions you see as germane). The fact that he did address these questions (albeit not to your satisfaction) is merely amusing.

The challenge is spurious because, speaking as someone who regularly deals with people functioning within the autism spectrum, Geoff evinces no signs in his text of an ASD. On the contrary, his post and answers give ample evidence of awareness of the context in which his answers will be read, social competence etc.

That being so, your challenge is an attempt to make autism per se a pretext for demeaning what someone else has to say, which is ethically offensive whether Geoff was to be counted within the ASD spectrum or not.

It’s also an implicit attack on the host here, who plainly believes Geoff’s post adds to insight. You’re throwing rocks against the gate, but when people ask what you want, you’ve nothing to say.

You should apologise and withdraw the remarks. They vilify those who actually have a disability and misrepresent someone who has made a useful contribution here.

And for the record, merely calling Animal Liberation “an extremist organisation” is meaningless. Extremism is meaningless without a an explicit referent.

You still need to show that Geoff had made errors the provenance of which were in his attachment to that organisation.


Bern: Tom has given a good response to your question, but here’s what I find to be the killer argument. Take all the current CO2 in the atmosphere. Strip off the O2s and replace them with H4. ie., turn it all to methane. The amount of carbon hasn’t changed. But the forcing has been multiplied by 25 and will stay that way for 10 years or so. HUGE difference without any extra carbon.

Fran/Tom: Thanks. I’ve often thought the emptiness of criticisms like podargus’s were so obvious that nobody would take any notice, but I’ve often been wrong about that. I’m astonished at how many people take notice of empty allegations … especially when repeated ad-nauseum. This is a big part of why climate skeptics are winning the public debate. They keep mouthing the same (usually empty) rhetoric. Scientists knock down any tiny argument and walk away thinking “ok, that’s done” … and it is. But it just keeps being repeated and the less substance the better, because with less substance there isn’t anything to argue with.


Scientists knock down any tiny argument and walk away thinking “ok, that’s done” … and it is. But it just keeps being repeated and the less substance the better, because with less substance there isn’t anything to argue with

These have been dubbed “zombie” ideas Geoff.


Geoff said:

This is a big part of why climate skeptics are winning the public debate.

I don’t agree that they are “winning” in the usual sense of the term. Winning on public policy for them means simply not losing badly. A loss on points is OK.

FUD and outright dissembling/lying works brilliantly when you are pitching for no change and can adduce cultural inertia and existing privilege to your cause. We’ve seen that both with climate change policy and nuclear power, to take examples from both broad parts of the cultural firmament.


Tom, Geoff, thanks for the replies.
I thought about it a bit more after I posted the question, and concluded that, while the C in the CH4 does indeed come from the atmosphere (via photosynthesis to produce the fodder), that the livestock industry has a net greenhouse effect precisely because of the reasoning in Geoff’s answer – that methane (and the extra forcing that results) may not stay there for long, but it’s being continually renewed as long as the livestock industry operates. Now, what the ‘natural’ level of methane emissions from ruminants is, I don’t know, but intensive cattle farming certainly exceeds that, and then there are the land-use issues Tom raised.


Douglas Wise, you say, ‘Recent advances in neuroscience are placing more and more doubts on the existence of any such structures or mechanisms even in non primate mammals.’

Could you provide some information on this? That is, where i could find out about the advances you talk about?


I can provide some information on this. I am not a specialist in the area, but have read around the subject quite a lot and written a review. The review contains many key references. The subject is not really relevant to this site. However, if you are genuinely interested in taking the time to follow up, contact me by e-mail and I will forward the review. My address is:


My dictionary defines sentient as “responsive to or conscious of sense impressions.” The protein myth serves the livestock industry well, and human consumers, the animals themselves (and nobody is arguing that mammals and fish aren’t sentient – of course only humans are human), and the planet badly.

While humans can be “omnivores” our biology is that of herbivores: from the density and shape of out teeth, through the carbohydrate-digesting enzymes produced in our mouths and the relatively weak acid in our stomachs, to the length of our digestive tract. Oh, yes, we can eat animals, but only in small amounts unless we want to have the health problems which our high-animal consuming culture bequeaths us.

The protein myth also has us scrambling to find alternative sources of protein – insects – when in reality eating whole foods not only provides us with all the protein we need, eating plants provides us benefits that we are only beginning to understand.


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