# CO2 emissions per calorie (food)

I have seen several lists with CO2 emissions by weight for producing several different food products. I think this is an interesting consideration, and possible argument for vegetarianism/veganism.

I would however prefer a list with CO2 emissions by calorie, as I feel it is a more useful at estimating consumption. Further more the above lists unfairly disadvantage calorie dense foods, or foods with low water content. I haven't been able to find a detailed list (e.g. this is to coarse for my purposes, but otherwise good), so does anyone know of such a list?

Preferably the list should be location neutral (i.e. if transportation CO2 cost is taken into account it should be general enough to apply for all areas)

• Though it relates to CO2 which is a common topic around here, it may work better on (chemistry SE)[chemistry.stackexchange.com/] or even (sustainability SE)[sustainability.stackexchange.com/], as the core information probably isn't something that an earth scientist such as a geologist or climatologist would directly study. – JeopardyTempest Apr 20 '17 at 9:53
• While I agree this is overall an interesting consideration, I would take these kinds of analyses with a big grain of salt. Nutrition and environmental impacts of agriculture (positive or negative) are both very complex and we miss out on important details when we simplify the issue down to only calories as the food product and only CO2 as the negative externality of agriculture. If you are interested in this sort of thing, I recommend studying agroecology. – cr0 Apr 20 '17 at 13:19
• If your idea is to suggest adjusting peoples diet in order to reduce the CO2 in the atmosphere then of equal or higher consideration, as opposed to vegetarianism, might be the reduction of unnecessary or wasteful exercise. – user7733 Apr 20 '17 at 19:59
• @user7733 An estimate for human carbon generation is 0.35 kg per 1000 calories burned. In my post below, I demonstrate that the difference between, say, pork and rice is about 2.5 kg per 1000 calories. Therefore, reducing unnecessary exercise should be of significantly lower consideration that switching to vegetarianism, by almost an order of magnitude. Please refrain from posting opinions without evidence on science-based Stack Exchange sites. – kingledion Apr 22 '17 at 0:17
• One problem you will have is the method of farming can have as large an effect as the thing being farmed. producing things in the wrong environment (california almonds), transport distances, and the wide range of differently efficient methods has a huge impact, together far more than the product itself. – John Apr 22 '17 at 14:20

I answered this question on SustainableLiving.SE. Since no one voted to close this as off-topic, I'll link and summarize my answer here.

I'm glad you asked for it by calorie, since answers on that question had found the data by kilogram, which is not a particularly useful measure. The data source for carbon per kilogram is the Meat Eater's Guide from the Climate Working Group (I believe this is the same as the website you linked, as well); I did the kilogram to calorie calculations from nutritiondata.self.com which gets its numbers from the FDA.

You can read my entire answer, but I will copy the data table for your convenience. Units are kg carbon dioxide emitted per 1000 calories.

Lamb         20.85
Beef         13.78
Turkey        5.83
Broccoli      5.71
Tuna          5.26
Salmon        5.15
Cheese        4.47
Pork          4.45
Yogurt        3.49
Chicken       3.37
Milk          3.17
Eggs          3.06
Rice          2.08
Potatoes      1.46
Beans         1.40
Tomato        1.39
Tofu          1.38
Lentils       0.78
Peanut Butter 0.42
Nuts          0.39

• Keep in mind these are average productions, across all types of farming/ ranching, Different methods will change these a lot. – John Apr 22 '17 at 14:11
• @John of course you are right, but do you have any measure of how much 'a lot' is? Are we talking +/- 100% or more than that? Sources would be helpful, but I can't find any – Toke Faurby Apr 23 '17 at 4:29
• Yes, to the point it may bring it down to a negative number for some crops, (carbon sequestration). There are just too many variables to give a hard number for everything, this paper will help. nuffield.org.nz/uploads/media/2008_Craige_Mackenzie.pdf – John Apr 23 '17 at 4:35
• Catching a wild salmon or shooting a wild turkey or deer seems very close to carbon neutral to me. There is no deforestation as there would be for agricultural crops. – DavePhD May 31 '17 at 11:08
• I think we should be avoiding naming Carbon Dioxide as "Carbon" on this science dedicated site - they are not the same thing, even if much of the time most people know what is meant. – Ken Fabian Dec 18 '19 at 20:33

I was recently on the hunt for comprehensive values of water, CO2 and energy per kcal of various foods. I found this post useful along the way, although I ended up using some other sources that had a larger variety of foods to create my own list.

The table of my findings (sources at the bottom) is attached here. Enjoy!