The Climate in Emergency

A weekly blog on science, news, and ideas related to climate change


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Climate Change and Food: Fake Meat

A cheeseburger sitting on a wooden surface against a dark blue background. The burger is seen from the side, up-close. It's in-your-face meat. The burger has two patties, lettuce, tomato, onion, and pickle, thin slices of yellow, semi-melted cheese, and a sort-of pinkish sauce. The bun is attractively brown and shiny and has a few white seeds on its surface.

Photo by amirali mirhashemian on Unsplash

Some time ago, I wrote a post on climate change and meat. I did some reading, and learned that, yes, animal-based foods do have categorically larger carbon footprints than plant-based foods. Worse, processing and transportation have very little to do with it–eating local, organic, minimally-processed etc. may be a good idea for many reasons, but climate change is not one of those reasons. The vast majority of the carbon footprint of an edible animal is simply due to the fact that it is an animal.

I couldn’t find a detailed explanation as to why, but a likely explanation has to do with the flow of energy. Simply put, every time energy changes form, a portion of it is lost (as per the Second Law of Thermodynamics) and the higher on the food chain you eat, the more energy has been lost along the way–and the more energy is involved, the more carbon emissions (I’m summarizing the post on meat, here, which I linked to above).

Lamb and beef, in that order, are by far the worst for the climate, at least in part because both are ruminants and therefor have digestive processes that produce huge amounts of methane, a powerful greenhouse gas.

So while I’m not going to say everyone necessarily should become vegan (only the Sith deal in absolutes!), it is clear that meat cannot remain a major staple for large numbers of people.

But many of today’s vegetarians and vegans eat diets that look and taste as much like omnivorism as possible, thanks to the wonders of food science. The prevalence of fake meat and dairy is only likely to grow as the fakes get more and more appealing.

So, what’s the carbon footprint of fake meat?

Carbon Foot-printing Fake Meat

Several dishes of food sit on a wooden table. The dish nearest the camera consists of cubes of tofu in a red sauce garnished with what looks like ground black pepper and chopped green onion. The other dishes are harder to see, but may be a large bowl of white rice, a dish of sauted green beans, and a dish of sliced eggplant in a brown sauce.

Photo by Alana Harris on Unsplash

What I’m calling “fake meat” here includes anything that can stand in for meat on the table but was never part of a living animal. In some cases the phrase is a misnomer. A portobello burger, for example, doesn’t resemble meat and isn’t meant to, it’s just a vegetarian dish that is good in some of the same ways hamburgers are. And ground beef made from cloned cells in a lab (which can be done, it’s just too expensive to market yet) is real meat by any reasonable definition, it just wasn’t taken from a dead animal. But “fake meat” is a reasonable shorthand for the entire dietary genre.

Clearly, with such a wide variety of possible foods, we’re not after just one carbon footprint. On the other hand, tracking down individual footprints for anything that could possibly be used as a meat substitute would be time consuming and, in some cases, fruitless (I have tried; there is a reason I’m posting one day late this week!).

What we’re really after is a generality; is shifting to fake meat really a good idea for the climate? The short answer is a very cautious yes.

Making the Sausage

Fake meat, by definition, isn’t what it looks like or tastes like, so the trick is to pay attention to what it is, not what it seems to be.

A meatless hot dog made of seitan, for example, has much more in common with a hot dog bun than a hot dog, from either a nutritional or environmental perspective. Seitan is essentially wheat protein. It’s made by rinsing all the starch out of whole wheat dough. Carbon-footprinting a seitan product therefore involves analyzing the emissions involved in wheat production, plus those involved with processing. A meatless hot dog made of soy might have a very different footprint, and lab-grown cells would be different yet again.

One of the most exciting fake meats at the moment is the Impossible Burger, which has been through multiple iterations and is currently made mostly out of soy protein flavored with heme, a molecule found in blood that is partially responsible for the distinctive taste of red meat. It is largely thanks to heme that the Impossible Burger is almost indistinguishable in taste tests from ground beef. Fortunately, heme is not found only in blood. In this case it’s produced by genetically-engineered yeast.

Carbon-footprinting the Sausage

The Impossible Burger has been the subject of formal footprint analysis; its global warming potential (including that involved in processing) is 89% smaller than that of beef. There are a lot of details I have not been able to gather about that analysis (the footprint of beef can vary slightly, depending on how it’s raised and processed and so forth, so did they use average beef, or one particular kind for the comparison?), but I have a hard time imagining that the unknowns could make more than a few percentage points of difference either way.

Some back-of-the-envelope calculations (using figures from this article) therefore suggest that an Impossible Burger patty has a carbon footprint somewhere between that of an equivalent weight of rice and beans and an equivalent weight of egg. From a climate change perspective, it is a vegetable.

Most other processed fake meats are likely in the same range, for the simple reason that they, too, are vegetables, and processing them is unlikely to involve substantially more emissions than processing the Impossible Burger does.

Lab-grown meat could be an exception, simply because it is so different from other products–it deserves its own analysis–but since commercially viable production methods have not yet been developed, it’s too soon to say what the emissions of those methods might be.

Complications

As I wrote in my post on meat, carbon-footprinting animal products may be a little less straight-forward than it seems. For example, milk has a much smaller footprint than beef does, presumably since the footprint of the cow is spread out over her lifetime production of milk, rather than the smaller bulk of her meat alone. So the more meals an animal produces, the smaller her associated per-meal carbon footprint is? If that’s the case, then beef made from a cow previously used for milk should have a smaller per-pound footprint than dairy does, since eating the meat spreads the animal’s emissions out even farther. But is that true, or is there a piece of the puzzle missing?

 

More troubling yet is the issue that cattle and sheep are hardly new, so how can their emissions be causing a new problem? The obvious answer is that there are far more cattle and sheep and other domestic animals than ever before–much of the zoological part of the biosphere is currently either humans or animals being raised to be eaten by humans–but before we created what I like to call the modern massive mountain of moo, there were lots more wild animals. How can domestic animals have more emissions than the wild animals they replaced?

The reality is that climate change is best understood by looking at the biosphere as a whole, not by adding up the carbon footprints of various individual activities. Prior to the Industrial Revolution, the levels of greenhouse gasses in the atmosphere were, roughly speaking, stable, because the energy flow through the biosphere was stable, inputs balanced by outflow, like a savings account kept roughly stable through careful budgeting. Lately, though, we’ve been spending down the account, an activity that produces the short-term illusion of riches but always results in poverty at the end,

There are two forms of spending down the account: we can take energy out of long-term storage, by burning fossil fuels, or we can take energy out of short-term storage through unsustainable use of natural resources, such as excessive logging. Although there are greenhouse gasses, such as CFCs, that are a bit of a different story, the bulk of the problem of climate change is a shift in the energy flow of the biosphere caused by one form or another of spending down the account.

The question is, how can the replacement of wild ruminants by domestic cattle and sheep change the energy budget of the planet? Isn’t a bovine fart a bovine fart whether the bovine in question is a steer or a bison?

I haven’t seen this issue addressed by any other authors, but in some way or other, the way we raise meat animals must either require fossil fuels or it must constitute an unsustainable use of a living system. If meat did neither, it could not alter the energy budget of the biosphere.

A Vision for Moo

There are certainly those who believe we must all go vegan, or at least nearly vegan, for the good of the planet. The statement is controversial, in large part because there are considerations other than climate in play. Eating animals is the subject of legitimate ethical debate, an important consideration, albeit an unrelated one (it is possible for two equally important issues to have no direct bearing on each other). Eating animals is also an intrinsic part of various cultural and economic systems (another important but different issue). And there are environmental issues associated with meat other than climate–for example, grazing animals have been used in ecological restoration (for examples and discussion, please read this book and that book). So how all these various considerations might pull and tug real life into the actual future is far from clear.

But I’m still stuck on how the mountain of moo changes the biosphere.

Meat animals can’t possibly be contributing to climate change simply because they are eaten by humans as opposed to by wolves or carrion beetles. Since we have it on good authority that they are part of the problem, they must be so either because fossil fuel is used on their behalf, or because they are themselves consuming resources at an unsustainable rate.

Vegetables could also be produced with fossil fuels and at an unsustainable rate, and they eventually would be if humans all went vegan but did not otherwise change our habits.

The solution is therefore to make meat (and everything else) fossil fuel free and sustainable.

Now, there would be much less meat in such a scenario, so diets would have to change, but that would be an effect, not a cause. It’s the energy budget we have to fix first and centrally, otherwise we’re just rearranging deck chairs on the Titanic.

Does that make switching to the Impossible Burger pointless?

Hardly.

We won’t build a new food production system if we continue to demand food that requires the old one. We have to create the tools we’ll need to build the future, and arguably that includes fake meat that meat enthusiasts want to eat. We need to develop the production systems, the distribution systems, and the cultural preferences that the future demands, and we need to do it today.

But let’s not forget that the one thing we really must stop eating is oil.

Image appears to show the instant after a drop has dripped into a liquid; there is a crater in the liquid surface, surrounded by rings of ripples. The liquid is black with a dull, pale sheen. It could be water seen at night, or black ink, or it could possibly be black petroleum.

Photo by Julian Böck on Unsplash


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Climate Change and Food: Red Meat

I have talked about climate and food before in terms of how climate change influences the food supply, but what about the other way around? How does our eating influence the climate? As many readers are probably aware, a significant amount of our collective carbon footprint (about one quarter) comes from our food system and meat-based foods have a larger footprint than plant-based foods. But how much difference between foods is there? What is the best way to cut carbon emissions out of one’s personal diet? Does it matter whether the meat is local or free-range?

I didn’t know either. So I’ve done some reading.

The numbers don’t look good for meat

The short answers are that the difference is huge, the best way to cut emissions is to eat less meat, and free-range and local do matter but, as far as the climate goes, not very much. There are some complications and nuances, of course.

I found an article that includes a graphic showing the carbon footprints of various food types (chicken, beef, eggs, lentils, etc.) expressed in kilograms of carbon dioxide equivalent (CO2e) per kilogram of food. “Carbon dioxide equivalent” means all greenhouse gasses taken together and expressed in terms of their impact on climate. So these figures include methane. Logically, the numbers would be exactly the same with any other measure of weight–the point is there is a ratio between amount of food and amount of emissions.

The simplest thing is to read the article, which you should do anyway because it’s fascinating. Here is the link. But I’ll summarize the most striking parts–for simplicity, I’ll give a single numbers for this; instead of writing “5kg of CO2e per kg of food,” I’ll just write “five.”

Lamb is the most carbon-intensive meat by far, at 39.2. Less than five of that is transportation and processing, which presumably means that if you raised your own lamb in your back yard, killed it yourself, and then had a carbon-neutral barbecue, it’s number would still be around 36. The next-closest competitor is beef, at 27, and then the other animal-based foods on the list cluster between 13.5 and 4.8. In contrast, the various plant-based foods on the list all cluster between just under three and just under one. The importance of transportation and processing varies, but only in potatoes is it the majority of the total figure.

I can think of several possible complications (besides grass-fed vs. grain-fed, which I’ll get to later).

  • What if the animal is a by-product of another industry? For example, if a flock of sheep are managed for milk and wool as well as meat, so that only excess ram lambs are slaughtered, then the carbon footprint of the flock is the same as it would be if those excess animals were not eaten (letting them live as pets would actually increase the carbon footprint of the operation, aside from the other ethical questions involved). In such a case, the same kilogram of CO2e has to share meat, milk, and fiber,and the whole operation is much more efficient than it might seem, right?
  • Do the figures for animals include emissions from transporting animal feed?
  • Why is the footprint of cheese six times that of yogurt given that most of them are processed milk?
  • The study focused on food in Britain; are these numbers different in other countries, such as the United States?
  • What is the footprint of highly processed foods, such as candy or fast food?
  • Since different kinds of food have different nutritional profiles, how would this comparison work if the unit of comparison were nutritional value, rather than weight? Nutrition is complex, so it might be impossible to do that kind of study, but the issue could still be important.

I do not have answers to those questions.

In any case, clearly generally similar diets, such as two different versions of mostly-plant-based omnivory, might have extremely different carbon footprints. The study that released these numbers found that while the difference between eating a lot of meat and eating a little is huge, the different between eating a little meat and none is small.

What is so bad about meat?

The clear take-home message here is that giving up beef and lamb (except possibly where these are byproducts of dairy production?), and cutting way back on other animal-based foods, is one of the most powerful steps a person can take to address climate change (aside from voting!). So, why are meats so bad for the environment? We have to be very clear, here; this is not about animal rights, which is an important but separate issue.

I have not seen this issue addressed directly, but the Second Law of Thermodynamics, not to mention public tastes in food, is almost certainly relevant.

The Second Law states, in essence, that every time energy moves or changes form, some of it is lost. This is why, for example, a ten pound house cat needs to eat more than ten pounds of meat in its life. This is also why ecosystems always have more plant-eaters than carnivores and more plants than plant-eaters. Most of what an animal eats does not become meat–what happens to it? Some of it becomes bone or other tissues we don’t want to eat. Some of it is never digested and simply passed as feces–which decomposes into carbon dioxide or methane–or as flatulence, which is also methane. But most of that missing food is exhaled as carbon dioxide.

One way to think about this is that all carbon that is taken up by plants is ultimately either interred in long-term storage as fossil fuels, or released again to the atmosphere when the plant rots or burns or is metabolized and exhaled. Eating food is the exact chemical equivalent of burning fuel. So, when a human eats a pound of plant matter, “burning” that “fuel” results in carbon emissions. But when we eat a pound of meat, that meat represents all the plants that animal ate to grow that meat–and all of that plant-fuel is “burned,” whether in the meat-animal’s body or in the human’s. More plant-fuel burned means more emissions released.

Cattle and sheep are both ruminants, meaning they don’t actually eat food directly. The food they swallow is eaten by bacteria in their guts, which in turn create food for the cattle. So you get another layer of energy transformation and thus another layer of energy dissipation–the bovine gets less energy out of the food and has to eat more, so more plants are “burned” as “fuel” for somebody. And the waste product of these bacteria is methane, which is a very powerful greenhouse gas.

So, meat has a larger carbon footprint than vegetables and ruminants (cattle and sheep) have a larger carbon footprint than other animals (pigs, chickens, turkeys, etc.).

Does grass-fed matter?

Most animals raised for the industrial food supply spend at least part of their lives–and sometimes all of them–in some version of a small cage being fed some kind of grain-based, heavily processed diet. There are all sorts of reasons why this is a terrible, horrible thing and why if you are going to eat meat, you should really choose only free-range animals (please note that “free-range” is a legally slippery term and that finding meat that lives up to the intent of the phrase takes some research). Is the climate another such reason?

The answer to that one depends who you ask.

An animal’s personal freedom has no particular bearing on carbon emissions. What makes the difference is whether it is grazing or browsing, as opposed to being fed corn (as would happen in a cage or cage-like feedlot). Logically, feed carries a larger carbon footprint because it must be transported and processed, whereas pasture is eaten where it grows. In fact, one of the best ways to keep open land from being converted into housing developments is to put cows on top of it. All of that argues for grass-fed meat having either a smaller carbon footprint, or possibly a slightly negative footprint, if pasture sequesters more carbon than cattle release.

On the other hand, cattle, at least, have to live longer to get to slaughter weight if they stay on pasture. More time living means more time farting, which could mean a larger carbon footprint. And while cattle are healthier eating grass, they get more energy from eating grain (which must be why they gain weight faster that way). So a day eating grass presumably means more farts than a day eating grain, too.

Which argument is actually true seems unclear at this time and might depend on the details of the cattle operation in question. And I have not found anything on how free-range living might influence the carbon footprint of other food animal species.

Wait–haven’t there always been cattle?

This question was posed by one of my Facebook friends and it’s a good question. How could cattle be a factor in increased climate change given that cattle themselves are hardly new?

This was my answer:

xkcd land mammals

From XKCD, https://xkcd.com/1338/, used in accordance with the cartoonist’s policy

 

This graphic shows that almost half of the land mammal compliment of the planet, by weight, is cattle. The vast majority is either humans or animals that humans eat. The reason it makes sense to do this comparison by weight rather than by head is that weight is a good proxy for how much animals eat and, thus, how much plant “fuel” they burn and how much CO2e is released. Consider that the energy in a pound of mouse meat is probably similar to the energy in a pound of hamburger–about the same number of calories. There are some potential complications here, but two thousand pounds of mice probably eat very roughly the same amount as two thousand pounds of cow. So, the fact that our planet has a huge number of tons of cattle right now means that a huge amount of plant-fuel is being “burned” by cattle these days.

Now, I am fairly confident that while there have been cattle for millennia, there have not been THIS MANY cattle until very recently.

I also suspect that this massive pile of mooing would not be possible without fossil fuel–and it certainly wouldn’t be economical. Feed could not be cheaply moved in to feed lots and beef (grass-fed or grain-finished) could not be distributed widely enough to meet enough consumers to justify the size of the herd. If this is the case, then excessive cattle farts are simply another symptom of fossil fuel use.

But, even if the huge herd of cattle is new, surely something else was eating all those plants before, and releasing a corresponding amount of waste and flatulence? Like, all the wild animals we’ve squeezed out of existence lately? Maybe and maybe not. Perhaps a lot of those plants used to just not get eaten and to enter into long-term storage on their way to becoming fossil fuel. Or maybe the wildlife released more carbon dioxide and less methane and so had a lower carbon footprint. There are possibilities. Or maybe the farts of cattle are actually irrelevant to climate change and the real carbon footprint of food is only the fossil fuel use and the ecological degradation associated with it?

That one I do not know.