Economists' Guide to Vegetarianism - Part 1

I am not a vegetarian; I just don't eat meat. My friends all think of me as a vegetarian, and it is for ethical reasons that I don't eat meat, but I still contend I am not a vegetarian. Rather, vegetarianism for me is the inescapable conclusion I come to when I think about my primary moral maxim: "Treat others how you want them to treat yourself." This concept, the golden rule, can be extended to a more useful form: "Choose behaviors that make you happiest assuming everyone else acted similarly." I will call this rule the sustainability golden rule. It is this rule, along with my preinclinations as an economist, that makes me not eat meat. The reason I make this conclusion is that it almost certainly impossible for the whole world to eat meat at the same rate as Americans (given our current technology level) without running into land constraints, environmental constraints, and irreparable harm from climate change (sources 1, 2, 3, 4, 5, 6). For this reason, eating meat fails my primary ethical maxim: not everyone can eat meat without severely damaging my own happiness.

But, I am considering starting to eat meat again, not because I want to, but because it would be ethically inconsistent for me not to eat meat. This sounds paradoxical given my strong ethical statement above, but I assure you it is not. Rather, it is the result of more precisely defining how I can meet my ethical standard. Let me jump straight to the punchline, and then explain the relevance later: the CO2-equivilent that is emitted per kilogram of food is generally highest for meat, but it is not so simple. See the table below for a small portion of the data I have pulled together.

Key points from this graph:

  1. Meats, especially Lamb and Beef, are the worst for climate change. The primary reason for this is that Sheep and Cows digest food with Enteric CH4 Fermentation (i.e. farting methane). The methane impact on climate change is extremely large, and until the last decade, has been largely underestimated. Pork and Chicken are much lower because these animals do not produce methane directly from digestion.
  2. Cheeses are also very high, more so for hard cheeses than soft cheeses. This is because to produce 1 kg of cheese, it requires approximately 8.89 kg of milk. In essence, this means you multiply the impact of milk (1.34) by the cheese's "yield factor" (which is 8.89 for Cheddar, approximately 22 for Mozzarella, etc.). Hard cheeses are worse than Chicken. This is a serious problem for cheese eating vegetarians.
  3. Organics tend to have more impact than non-organic versions of the same product. I will get much more into this in a later article, but the basic reason is that yield per input (such as feed, electricity, fuel) tends to be much lower for organic products. Even while the per-acre CO2e is often less for organics than the high-intensity methods, the lower yield means that the impact per output is higher. Put in simplest terms, an organic cow takes longer to grow to slaughter weight, and this means there are more farts per pound of beef over the cow's longer lifespan.
  4. Free-range cattle are MUCH worse for climate change than grain-fed beef, due to much higher methane production in grass digestion. All of the studies analyzed in this article agree with that conclusion, along with a large and growing literature that further supports this claim.
  5. Beans are a wonderful food.

I will devote a future article to defining and defending these numbers in much more depth, but as this is the intro article to this series, I will leave it at these five points and invite questions. Also, see the full table for over 100 foods at the end of this article.

Quantitative Vegetarianism and Econotarianism

To live by the ethical standard above, one would want to minimize CO2e while maximizing the tastiness, enjoyment and nutrition from one's food choices. Clearly, this is just a utility maximization problem with multiple constraints and a public good dimension, so the economists in the room ought to be salivating by now.

In this economics-friendly framework, vegetarianism is nothing more than a simplified behavioral rule that identifies a subset of food choices on the basis that vegetarian foods tend to have less environmental impact (ignoring for now non-environmental vegetarians). It is patently clear from the data that vegetarianism is a decent decision rule, as it eliminates nine of the ten highest-emissions foods, but it is not the optimal decision rule in this utility maximization framework for two important reasons:

  1. It is not a perfect ordering. Cheese is much higher in CO2e than some meats, such as Chicken or Fish. Moreover, the rule says nothing about discriminating between non-meat foods, even though eating rice over lentils would have an impact three times as large.
  2. It says nothing about how much you enjoy the foods in question. If it is a true utility maximization, then foods you love may fit the ethical maxim even if they have higher CO2e emissions, presuming they don't overshadow gains elsewhere. But, vegetarianism doesn't allow for this possibility.

So, being a vegetarian does get one closer to the sustainability golden rule, but it has problems and can be improved. What I intend to do with the rest of this series is to come up with a better behavioral rule than vegetarianism based on utility theory, empirical evidence of what exactly the environmental impacts of a choice are, and the concept of the sustainability golden rule. For lack of a better name, I will call this decision rule econotarianism.

Why I am Considering Eating Meat

The fact that I currently eat cheese (and love it) but do not eat chicken or fish means my ethical system is incomplete at best or flat-out contradictory at worst. Even before developing the formal econotarian criterion, it seem clear to me that to be ethically coherent, I would need to either eat chicken and fish or stop eating cheese. The latter option sounds better to me and seems more likely to actually fit my sustainability golden rule.

The Rest of the Economists' Guide to Vegetarianism

The rest of this guide will proceed to describe the climate impact graph above in more detail, define exactly how the foods are aggregated and studied, develop a formal model of econotarianism, discuss the philosophical underpinnings of the sustainability golden rule and extend the criterion to include concern for future generations, identify the additional non-climate related variables that ought to be included (such as water quality or animal cuteness), and finally, create an online-calculator that maximizes one's utility while meeting the sustainability constraint.

For now, I will end with the following table which outlines many more food options than I was able to fit in the graph above.

Continue to Part 2 of this guide: Low Hanging Beef Fruit.

Kilograms of CO2e Emitted per Kilogram of Food

Food Type

kg CO2e / kg food

Lamb - Extensive Upland

92.86

Lamb - New Zealand

78.57

Beef - Brazillian Suckler

72.73

Lamb - Intensive Lowland

66.67

Lamb - Organic Lowland

64.29

Beef - Organic Suckler

58.18

Beef - Extensive Suckler

54.55

Lamb - Idaho

27.47

Lamb -  (EWG Average)

24.16

Lamb - Medium Scale

23.52

Lamb - Large Scale

21.49

Beef - Nebraska

19.36

Beef - Dairy Co-Production Intensive

18.18

Beef (EWG Average)

17.99

Beef - Idaho

16.62

Pork - Organic Outdoor

15.23

Parmesan Cheese

13.83

Pork - Extensive Outdoor

13.69

Wisconsin Cheese

10.80

Gouda Cheese

10.80

Packed mild cheddar cheese

9.80

Pork - Some Pasture

8.98

Camembert Cheese

8.70

Feta Cheese

8.70

Duck meat

8.54

Pork - Intensive Indoor

8.46

Pork -  (EWG Average)

8.43

Pork - Confined

8.33

Pork - Outdoor Michigan

7.98

Farmed Salmon - Chile

7.93

Farmed Salmon -  (EWG Average)

7.46

Turkey

7.42

Chicken - Organic Outdoor

7.32

Farmed Salmon - Canada

7.28

Chicken - Extensive Outdoor

6.61

Farmed Salmon - Norway

6.51

Cream Cheese

6.26

Mozerella Cheese

5.84

Chicken

5.63

Chicken - Intensive Indoor

5.54

Buffalo Cheese

5.35

Canned Tuna

5.15

Eggs - Free Range

3.56

Eggs -  (EWG Average)

3.30

Eggs - Confined

3.04

Potato

2.90

Rice - Brown

2.70

Rice - White

2.70

Peanut Butter

2.50

Nuts

2.30

Tomatos - UK

2.30

Milk - Whole Idaho

2.08

Milk - Whole Wisconsin

2.00

Dry Beans

2.00

Tofu

2.00

Broccoli

2.00

Yogurt

1.82

Tomatoes - Spanish

1.80

Milk - 2% Wisconsin

1.65

Coffee – Cherries Kenya

1.50

Milk - Extensive Low Yield

1.44

Milk -  Organic

1.34

Pineapple Juice

1.34

Fresh pineapple

1.30

Milk - Intensive High Yield

1.24

Tomato

1.10

Lentils

0.90

Bread - White loaf in plastic

0.88

Tea – green leaves (Kenya)

0.87

Granulated sugar (from cane)

0.87

Bread - Organic Wheat

0.75

Wheat - Organic Feed

0.74

Soybean Meal Feed

0.67

Wheat - Conventional winter bread

0.64

Soybeans Feed

0.59

Organic UK Onions

0.59

Garlic

0.57

Wheat - Intensive winter feed

0.55

Barley - Winter feed

0.46

Onions - Conventional UK

0.42

Wheat - Extensive spring bread wheat

0.40

Tomatoes - UK Conventional waste heated

0.39

Wheat - Extensive spring feed

0.39

Carrot

0.35

Maize

0.34

Orchard Grass Feed

0.28

Ley silage - Intensive 5 year

0.25

Ley silage - Extensive 10 year

0.25

Corn Feed

0.23

Spring onion

0.23

Ley Grass - Intensive 5 year

0.22

Maize silage

0.18

Potatoes - Pre-pack

0.16

Alfalfa/Hay Feed

0.13

Potatoes - Processing

0.13

Potatoes - Organic pre-pack

0.12

Winter Beans - Organic

0.12

Ley Silage - Organic 3 year

0.12

Winter Beans - Conventional

0.10

Corn Silage Feed

0.08

Grass - Organic Permanent

0.07

Sugarcane - Zambia

0.05

 

Sources

I constructed this graph, and the more detailed graphs and tables provided below, from my own research and a wide variety of other sources (see below). The sources for the data are:

Wiltshire et al. 2006.  Scenario Building to Test and Inform the Development of a BSI Method for Assessing Greenhouse Gas Emissions from Food - Tefchnical Annex to the Final Report. DEFRA, Project Reference Number: FO0404, ADAS.

Capper et al. 2009, The environmental impact of dairy production: 1944 compared with 2007. J ANIM SCI June 2009 vol. 87 no. 6 2160-2167

Williams et al. 2005. Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities. DEFRA (Department for Environmental Food and Rural Affairs).

Hamerschlag and Venkat, 2011. The Meat Eaters' Guide to Climate Change. Environmental Working Group (EWG), Washington, D.C.

Hamerschlag and Venkat, 2011. Methodology to The Meat Eaters' Guide to Climate Change. Environmental Working Group (EWG), Washington, D.C.

And additional self-research on production methodology and yields. Wiltshire et al. 2006 and Hamerschlag and Venkat, 2011 were the most extensively used resources, while the other sources were primarily used to validate the numbers and approaches in these two documents.

 

 Continue to Part 2 of this guide: Low Hanging Beef Fruit.

About this Site

Justin Andrew Johnson is a PhD candidate at the University of Minnesota where he researches the economics of climate change.

This site combines examples of Justin's academic work with more lively discussions of society, video games, computer programming, politics and sometimes-irreverent humor.