Thoughts about greenhouse gas emissions and eating beef

Factual Questions
1

I’m familiar with the argument that cutting beef out of your diet is one of the more significant ways to cut greenhouse gas emissions (because not only are cattle energy-intensive to produce, particularly if they are not grass-fed, but also because they fart out methane gas).

But this beggars some questions for me:

(1) If humans switch to a plant-based diet, aren’t THEY going to be the ones producing the methane gas? (High-fiber foods are notorious for producing gas when digested…)

(2) Does this equation necessitate a bovine holocaust? (in addition to the everyday slaughter that cattle already face…) That is to say, wouldn’t we need to stop breeding cattle and allow their numbers to diminish to near zero? Do such stop-eating-meat-to-cut-greenhouse-gases calculations take into account the fact that the uneaten cattle would be wandering around, farting anyway? In such calculations, what’s the baseline number of remnant cattle a generation after cowpocalypse, where do they live, and what do they eat?

(3) How do current ruminant greenhouse gas emissions compare to earlier eras? Say, the days when bison covered the American great plains in uncountable numbers? Did they emit fewer tons of greenhouse gases than today’s cattle? (Not being snarky; genuinely curious. I know that we keep cattle in much denser environs now, so it’s possible that cattle today outnumber bison at their peak, and that total greenhouse gas emissions from non-ruminant sources were significantly lower in the preindustrial era.)

2

See, I have a problem with this considering 70% of the Earth is covered with water. On the remaining 30% of land, really how much of it is occupied by cattle?

It’s on the level of a mosquito fart in your house.

3

1: Cows produce methane because they use bacteria to ferment the grass they eat. The energy in grasses is almost entirely locked up as cellulose, which is tough and hard to digest. To get significant nutrition from gas, cows use inefficient bacterial fermentation.

We don’t eat grasses or ferment cellulose. Instead, we eat easier-to-digest parts of plants with high starch and protein content (compared to grass). Even the tougher plants we eat (say, broccoli) are made easy to digest by cooking. As a result, there’s not much methane production in our gut, even with a plant-based diet. My WAG is that the increase of human methane production would be dwarfed by the reduction of cow methane.

2: Smart-ass answer: don’t we already have a cow holocaust? Realistically though, we’re never going to suddenly stop eating beef. Rather consumption and demand will slowly go down over time, and beef producers won’t breed more cows than they can sell. Since beef cows are slaughtered before they are two years old (iirc), we could theoretically just stop breeding more cows right now and, without wasting anything, we could entirely stop eating beef in a few years. Again to be more realistic, a substantial decline in beef consumption over a decade or three would be manageable. The beef industry wouldn’t be happy… but due to the magic of market forces, they’d find ways to sell their beef at lower prices. In the short term, the unwanted beef would become something like cheap pet food, and a lot of produces would scale back breeding and/or go out of business.

3: Again IIRC, there are studies showing that methane production from grain-feed beef is lower than in pastured beef. I had a hard time believing it at first, but in fact that idyllic little farm that sells their beef at farmers’ markets is contributing more to global warming than a big industrial feed lot operation (per pound of meat). By extension, I think we can assume that in the past when cows grazed more and were fed less grain, they produced more greenhouse gases. But in total, we’re eating a hell of a lot more beef today than one or two hundred years ago.

4

Firstly the issue is not cattle farts, but cattle burps - under 5% of emitted methane is in the farts.

The real question is whether land now used by cattle could be switched to produce human-digestible crops, amounting to at least the same food value as the lost beef, and produce fewer GG emissions. In the US for instance, I believe the main cattle area is between the Mississippi and the Rockies, where the rainfall isn’t enough for denser agricultural activity.

There’s a great 15-minute podcast on exactly this topic here

transcript here

It says, in part:

The answer is not as simple as eating less (or no) beef, it’s eating less food overall.

5

Both Cattle and Sheep are part of the Chicken and Pigs have different digestive systems that don’t produce copious amounts of methane. Some Australian scientists are trying to figure out how to transfr DNA from Kangaroos to cattle, since the Kangaroos digestive system doesn’t product methane.

I also did some calculations that eating cheese made from cow milk also has a significant greenhouse footprint.

6

I am a Chemical Engineer by profession and deal with power plants and green energy. What bugs me most is how many folks are ignorant about the magnitude of emissions. Here are some numbers for starters (these are 2010 numbers) :

1> CO2 emitted by US Industries : 5,706 million metric tons CO2 equivalent
2> Methane by Cattle (Enteric fermentation) : 215 million metric tons CO2 equivalent

See Executive Summary Page 4 and 5

So roughly, 4% of US greenhouse gases are released by enteric fermentation i.e. Cow farts/burps (2010 numbers). So - even if you killed all the cattle, you’ll be left with 96% of the problem and considering the rate of energy demand increase, it will be unnoticeable.

If you really want to go after methane emissions (the 2010 numbers do not show this) go after the fracking regulations since as I understand, the fracking guys produce substantial emissions due to it being a new process and regulations not stringent enough. More here

7

Heh, I was about to post the exact same thing about methane emissions compared to pre-settlement emissions from wild ruminants (my cite says 70 percent for the low end, with the high end actually exceeding current emissions from cattle.

Also, the actual emissions are a drop in the bucket compared to total greenhouse gas emissions, based on my cite, which gives wild ruminant emissions as 0.23 teragrams per year (1 Tg = 1 million tons) and says that is 3.6% of domestic cattle emissions, which in turn puts cattle at about 6.4 million tons of methane a year; the highest estimates for methane’s GWP is 105 times that of CO2 on decadal timescales, which puts it at a rather high 670 million tons of CO2 equivalent, but that is only about 10% of total U.S. greenhouse gas emissions, and about half that for centennial timescales (and again, wild ruminants pre-settlement may have emitted more than this, and the the very least, a significant fraction).

Plus, methane from cattle originally came from carbon that was already in the environment, unlike fossil fuels, which effectively add new carbon that isn’t removed on meaningful timescales.

Also of note - Smallest U.S. cattle herd in 60 years may raise beef prices

So in the past 60 years, methane emissions from cattle have had zero impact on global warming. Of course, emissions from switching to grain-based diets is another story (cattle should be fed on their natural diet, and they can graze in areas otherwise unsuited for agriculture). Not to mention that grains make people unhealthier when they eat grain-fed beef (hint - the problem is the grains, not the meat; for example, they have an overwhelmingly large ratio of omega 6:3 fats, which are unhealthy in such high amounts (note the description of “prothrombotic, proinflammatory and proconstrictive”), that said, grain-fed beef still has a healthier ratio than grains themselves, not saying that grains are evil but this chart of calorie consumption by category is suggestive of the root cause of the obesity and diabetes epidemics).

Also, IMHO, growing vast amounts of food crops for automobile fuel (corn ethanol in particular, which consumes about 40% of the current U.S. corn crop, but also sugar cane and palm oil, which destroy rainforest) is an environmental and humanitarian crime (at least the residue can be fed to animals, but see above).

8

Some of these cites appear to be blogs and USA today articles. There are dissenting views on the impact of animal agriculture: for one, the UN report, Livestock’s Long Shadow (link takes you to an index of .pdfs).

9

I have no problem with eating beef in general, I have a problem with factory farming. Besides the fact that cattle based emissions are truly a miniscule sector of our total greenhouse gas sources, factory farming creates a vastly inferior product as far as health is concerned. The ratio of fatty acids is skewed with factory farmed beef towards the inflammatory O 6’s, and the extremely condensed nature of the farms creates issues with waste saturation, land destruction, disease proliferation, and poor livestock health. On the other hand, free range/pasture animals actually benefit the ecosystem through their grazing, not to mention that they can be grazed on land that is unfit for agriculture. Just look at mountain pastures in Switzerland, or herding Goats(Yes, not Cows, I know) in Greece. The only advantage to factory farming is greater meat availability, but is it worth it for a subpar product?

10

If you believe that climate change is the result of man made C02 emissions, the only way to significantly reduce the amount of such emissions is to significantly reduce the human population.

11

a necessary idea that will eventually become mandatory if not done voluntarily.

it would have been easier if that was started half a century ago.

12

Totally true. Similarly, car crashes are the result of human error; the only way to significantly reduce the amount of such crashes is to significantly reduce the human population.

In neither case is it remotely reasonable to discuss changing human behavior.

13

So your position is that it is only ever possible to increase per-capita CO[sub]2[/sub] emissions, it is flatly impossible to decrease them under any circumstances?

14

I think the point is, there are much better ways to decrease emissions than not eating beef, which only accounts for around 5% of total emissions (ignoring inputs from feedstock, which can be carbon neutral). For example, renewable energy sources and more efficient appliances (especially cars), which can easily decrease emissions more, and lets not forget that, unlike fossil fuels, methane emissions from cows don’t accumulate in the atmosphere because the methane came from food that the cows ate, which in turn came from carbon from the air (and per the story I posted about the cattle herd being the smallest in 6 decades, there has been zero contribution to global warming over that period, again ignoring the changes in farming practices, but the point here is that cows themselves aren’t the problem; if you are still concerned, eat organic pasture-fed beef).

15

If carbon emissions created by man’s consumption of resources, for food, transportation, heating and cooling, clothing, entertainment, etc. are the cause of climate change, then no amount of reduction that will come about from eating less beef, driving more economical cars, using more efficient water heaters, will make up for the multiples of population growth over the last century. And then add to that the increasing development of populations in nations like India, China, etc. and while those actions will decrease the emissions, it will be miniscule in comparison.

If the world is hurtling toward cataclysm as many climate alarmist say we are, then the only sure fire way to reverse the impact is to drastically shrink the absolute population of the planet.

16

What about renewable energy sources that are carbon-neutral? Fossil fuels are the crux of the problem, not just because of the emissions but because they enabled the population growth in the first place. Of course, energy isn’t the only problem, since resources of many of the other things we consume are being depleted, including, for example, fertilizers mined from phosphate rock (instead of doing it the natural way, but no, our waste MUST be disposed of so we can’t see/smell it, and, eww, I’m not eating that!).

And FWIW, your use of terms like “alarmists” makes me very skeptical of anything you say.

17

You appear to be unaware of current demographic trends. Earth population should peak around 2050. North and South America, Europe and most of Asia are already at ZPG.

http://www.google.com/publicdata/explore?ds=d5bncppjof8f9_&ctype=l&met_y=sp_dyn_tfrt_in#!ctype=l&strail=false&bcs=d&nselm=h&met_y=sp_dyn_tfrt_in&scale_y=lin&ind_y=false&rdim=region&idim=region:LAC:EAP:ECA:NAC&ifdim=region&tdim=true&hl=en_US&dl=en_US&ind=false

18

You must be unaware of past demographic trends. In 1927 world population was approx. 2 billion. It is currently approx. 7 billion, and is expected to be about 8 billion in 2025. That’s a 4x growth over the past 100 years.

Climate scientists claim it is the human interaction over the past century that has created the problem we have with climate change today. Taxing carbon emissions, regulating fuel economy of transportation, mandating light bulb manufacturing, etc. etc. is a drop in the bucket and is futile against the 4x population growth. The only way to make a significant impact based upon what is claimed to be the problem is to drastically reduce the population size. Any other proposals don’t really take the claims of these scientists seriously.

19

Considering that the global temperature haven’t increased in the last 14 years, we have to assume that forecasting skill of these climate scientists leaves a lot to be desired. If you think the earth’s population needs to be decreased drastically, then I suggest you first.

20

Says who? Here is what NASA says:

Maybe you mean the Daily Mail, hardly a reliable source.

FWIW, you may have also missed the news that HadCRU was fixed to correspond more with the other data sets (they previously showed less warming in recent years, due to a well-known flaw with sea surface temperatures).