Hard to swallow
July 23, 2023 8:32 AM   Subscribe

Vegans, vegetarians, fish-eaters and meat-eaters in the UK show discrepant environmental impacts

The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review

Climate change mitigation through dietary change: a systematic review of empirical and modelling studies on the environmental footprints and health effects of ‘sustainable diets’

How Government Policies and Regulations Can Affect Dietary Choices

3.2 HOW ARE FOOD AND AGRICULTURAL POLICIES AFFECTING DIETS?

While the collective use of our food dollars can exert economic pressure on the food system, we can exercise even greater change by moving beyond our role as “food consumers” to that of “food citizens.” In addition to making informed food choices that reflect their values, food citizens leverage their political power to shape food and agricultural policy.

6 Ways to Get Involved with Food Policy

It is important to eat according to one’s values—organic, fair trade, local, etc.—but conscious consumption—essentially a market-based approach to transforming capitalism—comes up short because sooner or later capitalism ends up absorbing these products into the system. Conscious consumption needs to be paired with activist citizenship to avoid being divested of its political power.
posted by latkes (39 comments total) 19 users marked this as a favorite
 
The shocker here, for me, is Figure 2B: unlike all the other comparisons, for CH4, vegans have a massively smaller footprint than everyone else. It's a shock to me because my thinking about CH4 had been along these lines (from TFA):

CH4 is a GHG that, in terms of agricultural emissions, is predominantly associated with production of ruminants—it is therefore unsurprising to see wide disparities in CH4 emissions associated with the different diet groups.

Yeah, duh. But if CH4 is mostly about ruminants, then why is the gap between vegans and everyone else nearly as big as the gap between high meat eaters and everyone else?

Nothing else in the study was much of a surprise, but that was. I'd like to understand it better.
posted by gurple at 9:17 AM on July 23, 2023 [1 favorite]


25%, higher than expected, consistent with what I have seen before, but we make the vegetables from petroleum, so.

Since nearly all food is based on petroleum, has anyone looked at the conversion from MAP and DAP production from the old Haber-Bosch to the newer Steam Methane Reformer methods?

That is what the chemical lobby is banking on,but I don't know how to evaluate it

If the chemical lobby is correct, and petroleum based fertilizer is made lower carbon intensity by SMR, meat eating is going to become much more of a gradient

So far though, there are no promises to close the old Haber Bosch plants!
posted by eustatic at 9:18 AM on July 23, 2023 [5 favorites]


My dad read Diet For a Small Planet and became a nearly vegan Vegetarian back in the 70s or 80s. We know this. We have been knowing it. Maybe this new wave of research will inspire more people like my dad.
posted by Bottlecap at 9:27 AM on July 23, 2023 [14 favorites]


The shocker here, for me, is Figure 2B...

Oh, I figured out my own stupid question. Everyone but the vegans is presumably eating a bunch of dairy. Hence ruminants, hence high CH4.

I'd love to see dairy broken down into high-medium-low the way meat-eating is.
posted by gurple at 9:31 AM on July 23, 2023 [16 favorites]


From a land- and resource-use perspective, I suspect that dairy-cattle farming is as intensive as meat-cattle farming. The ultimate disposition of the animals isn't the important thing; the number of ruminants is. And dairy farmers will obviously increase the size of their herds to the utmost limit of market demand plus government subsidy.
posted by graphweaver at 9:47 AM on July 23, 2023 [4 favorites]


We know this. We have been knowing it.

Nothing else in the study was much of a surprise...


Same here, but I admired the updating: new data, expanded criteria.
posted by doctornemo at 11:15 AM on July 23, 2023 [5 favorites]


Sorry to focus on the states, but I wonder if there is any study to see how the meat packer consolidation over the pandemic affects climate.

From a matter of policy, meat is cheap because the packers have consolidated against the ranchers and are using child labor. Is the next wave of food policy connected to reversing the packer monopolies?

On the other hand, "hamburger prices" is like a national issue that parties feed the need to respond to....
posted by eustatic at 11:18 AM on July 23, 2023 [2 favorites]


While it's pretty obvious that mo-meat mo-emissions, having the quantified breakdown of how much more emissions is quite helpful, especially for people trying to concretely compare the impact of different interventions at either the individual or population level. Especially for methane: we see a big step down between meat-eating and vegetarianism, but an additional large step for vegetarianism to veganism.
posted by kaibutsu at 12:15 PM on July 23, 2023 [4 favorites]


One thing that surprises many people is that for many people, eliminating all beef and dairy would be a bigger step down in food carbon footprint than going vegetarian and leaning heavily on dairy. This isn't as clear from studies of diets, but is clear from lots of research on GHG associated with certain foods (e.g. this review shows cream being higher in climate impact than chicken!).

(yes of course this depends on specifics of how the food was produced and how much cheese you'd eat as a vegetarian. But the point is methane is a super potent GHG. Also beef is the worst in terms of water use, which also has a carbon footprint.

TLDR: decreasing consumption of ruminant products is among the most important (and 'easiest') things a typical middle class Anglosphere omnivore can do to reduce their climate impacts.
posted by SaltySalticid at 12:37 PM on July 23, 2023 [7 favorites]


One thing that surprises many people is that for many people, eliminating all beef and dairy would be a bigger step down in food carbon footprint than going vegetarian and leaning heavily on dairy

The first link didn't look into this (perhaps they couldn't with their available data), but the second link shows a range of estimates; from a GHG perspective the reduction of pescatarian and vegetarian diets was in the 30% range, while replacing ruminant meat with monogastric was around a 20% reduction. (With vegan at 45%.)

That's the switch that my household has mostly made; sure, a steak or burger or roast like once a month, but like tonight I'm making tacos and the ground meat is pork instead of beef. (I haven't found a decent vegetarian version yet). Same for chili, lasagna, etc. It's a big reduction in our food footprint with relatively little 'cost' in terms of our preferences.
posted by Superilla at 2:05 PM on July 23, 2023 [1 favorite]


Methane is a very potent GHG, but I think we're overstating the contribution from methane in this data. On the GWP100 basis, only about 22% of the difference between a vegan diet and a medium meat-eating diet is due to methane. Even looking at GWP20, it's still only 46% of the difference.

The reality is that the other big factors in beef production are also quite important, namely land-use change and grain feed production (and these are factors that can be somewhat controlled). Reducing meat consumption is definitely a good thing, but given that it is very difficult to get people to stop eating meat (and, on a global scale, to prevent those who are getting richer from starting to eat more meat), looking at how we can raise cattle without cutting down the Amazon or growing vast areas of grain for feed is also very important. I also think there are opportunities to replace beef with pork in some instances, though the industrial farming of pork has a long way to go as far as sustainability.
posted by ssg at 2:15 PM on July 23, 2023 [2 favorites]


The great thing about cutting beef out of your diet is that (for my family, at least) it becomes self-reinforcing.

I can count the number of times I've eaten more than an ounce of beef in the last 15 years on one hand, and every one of them led to significant physical distress of the bathroom variety.
posted by gurple at 3:07 PM on July 23, 2023 [3 favorites]


If you don't want to give up meat, eating one billionaire will offset your carbon footprint more than a lifetime of veganism.
posted by AlSweigart at 3:15 PM on July 23, 2023 [24 favorites]


Demonstrably true!
posted by latkes at 3:24 PM on July 23, 2023 [1 favorite]


I just looked at the first link, and I'll admit I skimmed some of the more technical bits so maybe I'm missing something, but what I'm curious about is that for most of the measurements, there are some vegans with as large of a foot print as some low-meat eaters. That seems interesting and I'd be curious to know more there - i.e. what allows some low-meat eaters to have the same impact as some vegans? It doesn't seem to be addressed in the article, but if it is and I missed it, I'd be curious to know.
posted by coffeecat at 4:20 PM on July 23, 2023


Kill your own local free range meat vs flying in asparagus from the other side of the world?
posted by biffa at 4:55 PM on July 23, 2023 [1 favorite]


coffeecat wrote:
I'm curious about is that for most of the measurements, there are some vegans with as large of a foot print as some low-meat eaters. That seems interesting and I'd be curious to know more there - i.e. what allows some low-meat eaters to have the same impact as some vegans?
I dug into it a bit. Note that Fig. 2 is showing the results of a Monte-Carlo analysis – that is, a simulation – and that the uncertainty intervals are almost certainly showing the left and right tails of a bell curve. So, to take one example, the 97.5th percentile right tail of "vegans" for "N20", which is to the right of the median for "vegetarians", represents a quite small number of simulated cases. The simulation also aggregates all ages and sexes, so there are "male 20-29" cases and "female 70-79" cases lumped into a single "diet" class; as the study notes there was no significant difference in the aggregate results, but when are looking at individuals there does appear to be an effect (and I do see that they normalized to 2000 calories, I don't quite see yet how that squares with the female 70-79 results being so much lower than the male 20-29 ones).

Anyway, long story short, in a randomized simulation, there will be some results that come in a couple standard deviations from the mean. That doesn't mean that they observed these effects, but that they are plausible given the consumption patterns they found in the source data.
posted by graphweaver at 5:15 PM on July 23, 2023 [5 favorites]


I see, when I read "Here we link dietary data from a sample of 55,504 vegans, vegetarians, fish-eaters and meat-eaters" I thought that meant they had 55,504 actual people keep food logs, and then the results represent the range for each group - but you're saying this was just a simulation? I guess I'm still slightly confused, but thanks for responding.
posted by coffeecat at 5:57 PM on July 23, 2023 [3 favorites]


They got the data from a 130-item Food Frequency Questionnaire.
Dietary assessment was conducted using a 130-item FFQ that assesses the usual levels of consumption of food items over the previous 12 months.
Where the Monte Carlo simulation comes in, if I'm reading the paper correctly, is that each food has a range of possible environmental impacts. If you eat an apple, how many miles did it have to travel to the grocery store? How much fertilizer did it need? How much water did it need? You can keep track of how often you eat apples, but you can't keep track of the conditions under which the specific apple you ate last week were grown.

So they could just say, well, the average apple has this much carbon footprint, but it's probably more accurate to use a Monte Carlo simulation to simulate apples with a wide mix of carbon footprints based on the best data they can find about what carbon footprints apples grown under a wide range of conditions have.
posted by Jeanne at 6:46 PM on July 23, 2023 [5 favorites]


Where the Monte Carlo simulation comes in, if I'm reading the paper correctly, is that each food has a range of possible environmental impacts. If you eat an apple, how many miles did it have to travel to the grocery store? How much fertilizer did it need? How much water did it need? You can keep track of how often you eat apples, but you can't keep track of the conditions under which the specific apple you ate last week were grown.

There's two parts where the simulation comes in; the first is as you mentioned, but the second is that if someone eats apples, sure, you can look up apples. But another category of food from the study is vegetable soups; there's a wide range of what could be in a vegetable soup; a carrot puree has a different climate impact than cheesy broccoli chowder. (There are only two categories of soup in the EPIC-Oxford survey; vegetable and meat, because there are thousands of kinds of foods people can eat but you can't reasonably ask thousands of questions to people, so there's always a trade-off between detail and getting people to answer the thing.)

It's also worth noting (while I'm digging into the details) that it's a circa 1990 dietary record. They use current estimates of GHG from the foods, but the mix of foods also has changed over time. On the meat-eating side, for instance, I feel like beef consumption has declined (this study* shows that meat consumption in the UK has declined 2008-2019 -- which could be in part more vegetarians, but if you dig into the table, the proportion of meat that is beef has also declined.) On the vegetarian side, there are whole categories that didn't really exist 30 years ago; my supermarket has a massive cooler full of nut, seed and plant milks, and I'm sure it's not for show. It's plausible that some of these food shifts have led to higher GHG production for vegetarians/vegans.

* the study I link also shows why these researchers used the 1990s study; the one I link uses food consumption records from a representative sample of 15,655 people in the 2010s, and of those 15,655 there are only 334 vegetarians and 26 (twenty-six!) vegans. EPIC-Oxford specifically recruited vegans and vegetarians (in addition to random members of the public).
posted by Superilla at 8:36 PM on July 23, 2023 [7 favorites]


biffa: Kill your own local free range meat vs flying in asparagus from the other side of the world?

The impact of meat raised in your own back garden is almost certainly still higher than flying vegetables around the world, yes. It sounds ridiculous, or maybe a gotcha or exception, but it's true.

Asparagus is specifically discussed by Our World in Data:

Let’s take the example of asparagus.

If you live in the UK, you may have noticed on food labels that asparagus is often imported from Peru. They often come by plane. How does this affect their carbon footprint?

The average carbon footprint of asparagus is around 0.4 kilograms CO2eq per kilogram. Flying from Lima to London is around 10,000 kilometers. If we were to fly one kilogram of asparagus over this distance, this would emit around 11 kilograms of CO2eq [10,000km * 1.13 kilograms CO2eq per tonne-kilometer for flying / 1000 = 11.3 kg CO2eq per kg]. Suddenly the footprint of your asparagus changes from being a low-carbon food to a relatively high-carbon one, at almost 12 kg CO2eq per kg. It has a higher carbon footprint that a kilogram of chicken or pork.

It is the fact that it’s flown, rather than the travel distance itself that gives asparagus a large footprint in this example. If it traveled the same distance by boat, the travel emissions would be only 0.26 kg CO2eq per kg [10,000km * 0.026 kilograms CO2eq per tonne-kilometer for transport by boat / 1000 = 0.26 kg CO2eq per kg]. So its total footprint would be around 0.67 kg CO2eq per kg, which still makes it a low-carbon food option.


Compare that 12kg of carbon to the 99Kg of carbon from beef, or 39kg from sheep.

Very little food is flown around - https://ourworldindata.org/food-transport-by-mode

The carbon impact of beef is 100 times that of bananas, including transport, because they travel by ship.
posted by BinaryApe at 12:56 AM on July 24, 2023 [11 favorites]


I wonder a bit though about farmed animals also as living beings which seems kind of missed. Like the environmental impact of sustaining the life of a cow to get its milk involves supporting a living being who might not exist otherwise whereas shipping a banana across the world feels more of a waste because nothing living is sustained in the process of shipping. What are some ways of thinking about coexisting with animals like cows sheep from a vegan and environmental perspective? Are cows inherently unenvironmental because of resources needed to sustain them or is it something about how the industry is structured?
posted by mosswinter at 4:33 AM on July 24, 2023


I'll accept this, but we need serious investment in considerably improving dairy-less soft, aged cheese, pate, and oyster equivalents. I don't care if it's lab grown, but as representative of the smug, dissolute, hedonist chapter of humanity, I'm willing to make sacrifices here, but I'm going to need something to replace the cave-ripened triple creme $12 wedge of pure sublime bliss that is sometimes the only thing standing between me and surrendering to the chasm of despair.
posted by thivaia at 7:21 AM on July 24, 2023 [8 favorites]


I had some vegan cheese - sort of sharp cheddar slice imitation - a few weeks ago, and they're steadily working on it.
posted by Selena777 at 7:34 AM on July 24, 2023 [1 favorite]


Dairy-free cheeses have come a long way. Among other brands, Bandit (formerly Conscious Culture), Miyoko's, Violife, Kite Hill, and TreeLine are all good.

Having never eaten pate or oysters, I have not tried to find plant-based analogues.
posted by wicked_sassy at 7:36 AM on July 24, 2023 [1 favorite]


I know these analyses have a million moving parts and it’s impossible to account for everything, but it feels disingenuous that beef production gets dinged for land use change when the reason we have deforestation for beef production is because the prairies, which used to be massive sequesterers of carbon and a very efficient system for supporting enormous numbers of bison, waterfowl, and other animals, have been drained of their wetlands and turned into cereal monocultures. Those cereal monocultures aren’t getting penalized in the models the same way for the destruction of the prairies, which were a beautiful ecological and food production system that actually require millions and millions of ungulates to function.

On the one hand, they’re trying to make these models based on the food production we do have so we can make hopefully rapid changes to our agricultural system to slow climate change. On the other hand, they’re basing these models and recommendations on the very broken food production systems we do have and may be pushing us in directions that lead to even less biodiversity in the long run.

I think the recent agroecology post is really encouraging because it acknowledges that food production happens in ecosystems that we can work with instead of obliterating.
posted by congen at 7:41 AM on July 24, 2023 [2 favorites]


The most effective emissions-reducing diet is the one people will actually eat. So maybe focusing on aiming for pescatarian with meat once a week is the short-term goal. Especially since no one who likes cheese is going to go vegan for the climate as long as rich people are still flying everywhere on private jets.
posted by vim876 at 7:51 AM on July 24, 2023 [2 favorites]


(Isn't a significant percentage of the cereal monoculture primarily being grown to feed the beef?)
posted by latkes at 9:08 AM on July 24, 2023 [2 favorites]


Having said that, I eat mostly vegan (with fish/dairy/eggs once a week or so) and as mentioned above, recent advances in vegan food mean I have been eating a ton of nuts which are extremely water intensive and/or shipped from the other side of the planet. Having said that, interesting to read the above on the different impact of shipping vs flying. I wonder what foods are flown vs shipped?
posted by latkes at 9:25 AM on July 24, 2023 [1 favorite]


(Isn't a significant percentage of the cereal monoculture primarily being grown to feed the beef?)

Beef, yes, as well as pork and chicken - but even more is used for ethanol fuel. (About 40% of the US corn crop is used for ethanol, 36% for animal feed. We export a lot of the remainder and eat the rest, especially as high fructose corn syrup. )

Because it's apparently unthinkable to suggest to farmers and people in farm states that maybe we don't need to grow 382.9 million tons of corn every year, so if we're not going to use it as animal feed we're going to put it in our cars or sweeten our sodas and ketchups with it.

Land use in the Midwest is environmentally disastrous, and one of the reasons I stopped eating meat is that cereal monoculture on that kind of enormous scale didn't seem sustainable (now that I know more, it seems even less sustainable), but if we're not growing that corn for ourselves to eat, we're not growing that corn for animals to eat, we're just processing it and setting it on fire (so to speak) - I don't know how we get people to move away from that.
posted by Jeanne at 9:43 AM on July 24, 2023 [9 favorites]


A lot of the cereals fed to animals are grown on land that could support large numbers of animals we could eat. The number of ungulates in America hasn’t really changed since colonization - just how many of them are cattle vs bison, deer, etc (which is a reason to take the methane emissions comparison with a grain of salt - ungulates gonna burp!).
posted by congen at 10:15 AM on July 24, 2023


The number of ungulates in America hasn’t really changed since colonization

Not being sarcastic, but do you have a cite for this?

Also, deer emit a lot less methane than cattle, per head.
posted by ssg at 10:28 AM on July 24, 2023 [1 favorite]


I wonder a bit though about farmed animals also as living beings which seems kind of missed. Like the environmental impact of sustaining the life of a cow to get its milk involves supporting a living being

Although put another way, the impact of sustaining the life of a cow to get her milk typically involves keeping her confined, artificially inseminating her to get her pregnant more often than she naturally would and feeding her with hormones and antibiotics to make her produce an unnatural amount of milk, taking her calf away within thirty-six hours to the distress of cow and calf, killing most of the calves if they're male, and then making the cow pregnant again every year, rinse and repeat until she's milked out and kill her at about five when her natural life span would be 20-25 years. Not sure 'supporting' is quite the right word.
posted by reynir at 11:16 AM on July 24, 2023 [5 favorites]


do you have a cite for this?

I've heard a few prairie ecologists say it, but it's not my area so don't know the current literature. There are classics in conservation biology though from the 1920s (Seton - Lives of Game Animals) and 1950s (Matthiessen - Wildlife in America). I'm sure their estimates been refined, but even looking at post-contact bison estimates from the late 18th century shows 60 million bison vs. ~90 million cows now.
posted by congen at 12:24 PM on July 24, 2023 [1 favorite]


deer emit a lot less methane than cattle, per head

in case you need a break from the numbingly horrifying implications of our predicament
posted by elkevelvet at 12:54 PM on July 24, 2023 [1 favorite]


in case you need a break from the numbingly horrifying implications of our predicament

I like that every deer poots like it spent the whole day in an elevator crowded with people it wants to date, and just got home.
posted by The_Vegetables at 2:28 PM on July 24, 2023 [1 favorite]


Interestingly, it seems that cattle emit 2-3 as much methane as bison, so it's not just the number of animals that we need to look at.
posted by ssg at 5:26 PM on July 24, 2023 [1 favorite]


deer emit a lot less methane than cattle, per head, problem is (farmed) deer come with other issues.

1 - in the rut the males seek to make (very large) holes to make themselves look beautiful. A farmer told me they can detect water 2metres down and will then start excavating - runoff to waterways from deer is worse than dairy cows. They also make a serious mess of paddocks in general.

2 - deer are seriously dangerous to handle.

The absolute worst dairy farming at moment is the growing of fodder in dry iriigated US states and shipping it back to the Middle-East so the Saudi's can feeed it to dairy cattle. That is crazy, even crazier than New Zealand's business model.
posted by unearthed at 9:01 PM on July 24, 2023 [1 favorite]


We've good vegan cheeses in the biocoops in France and in the supermarket in Switzerland. You apply a cheese-like process to nuts basically, so really you can make them at home if interested. It's some trial & error initially but the process appears simpler than homemade bread.

Almost the whole word is lactose intolerant, even India and France, with northern European ancestry being the only reliably exception. Also, there are diverse milk intolerance besides lactose itself, so those lactose pills cannot help everyone. It should not be so hard to cut this shit out from our collective diets, or at least remove all these asinine subsidies.
posted by jeffburdges at 2:08 PM on August 2, 2023 [1 favorite]


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