My boyfriend and I like to debate various topics over breakfast, especially when drinking our coffees.
This morning, he argued that the meat industry has a far greater impact on the environment compared to the dairy industries — mostly because of the massive post processing chain and the long distances meat has to travel to undergo specific transformations. But for me, a vegan with a (somewhat strong) bias against the dairy industry, it wasn’t so obvious that the production of dairy had a negligible impact compared to the meat industry. You see, milk and its derivatives are everywhere! Crisps, crackers, cereals, ice cream… most of these processed foods contain milk ingredients.
This conversation did spike an interest and got me to look a little deeper:
- First, let’s check the facts.
The first time I heard about potential GHG emissions reduction when adopting a vegetarian diet was when reading about the study by Scarborough et al. (2014) comparing typical UK diets. In this study, high meat-eaters are those who eat more than100 g/day. To put this into perspective, the average meat consumption per capita in Canada was 150 lbs per year in 2018, or 186 g/day (1). Therefore the average Canadian would be classified as a high meat-eater according to this ranking system.
The presented data show that eating meat is the highest emissions contributor, while the emissions difference between eating fish and being vegetarian is negligible when compared to high-meat heaters (only 1% difference).
By moving away from an intense meat consumption diet and going vegan, you would therefore reduce emissions 13% more than by going vegetarian. “Really ? OK that’s not bad” I thought out loud. Let’s try to dive a little deeper.
2. What is happening in Canada ?
Assessing emissions from a diet pattern is not an easy task. In fact, it vastly varies depending on the land, supply chain, soil type, and whether the food is locally produced or imported. Canada has not choice but to import a lot of veggies and fruits throughout the year due to harsh and long winters. Is eating asparagus in the middle of winter more energy intensive that eating avocados in the summer ? Sounds like a tough call to me.
Another difficulty in the research comes from data collection (would you really report on everything that you eat ?). Vegans learn to eat a great variety of fruits, veggies and nuts from to get various nutrients which would need to be considered.
In 2017, Anastasia Veeramanis and some of her coworkers from the University of Waterloo published a paper attempting to assess the carbon footprint of different dietary patterns in Ontario, using Ontario’s latest food intake dataset which dated back from 2004 (yes it is old, I hear you grinding your teeth but that’s the only dataset they had back then… we might as well work with it). In the collected dataset, the average omnivorous consumed 17% of its yearly calories from dairy and eggs and 7% from meat. One striking fact about the collected dataset is similarity of eggs and dairy consumption between all types of meat and fish eaters.
The authors developed a full life cycle analysis to characterize the emissions of each food item in the diet including the different origins of the ingredients. As an example, beef was imported from Alberta while canned tuna came from Thailand. The key outcomes of this research shown in the figure below are interestingly consistent with the previously mentioned study from the UK.
Here again the difference in GHG emissions from switching from a vegetarian to a vegan diet is ~9% per year compared to 53% when switching from omnivorous to vegetarian. One limitation this study neglects is the presence of milk derivatives in most snacks and processed food which are not accounted for in the emissions factor of the meat-eating and vegetarian diets. But I get it, this would be an extra mile in the calculations.
3. So that’s it ?
Well, not quite. One Canadian researcher named X.P.C.Vergé published numerous articles on the topic specifically related to the meat and dairy emissions in different parts of Canada. In (4), the authors created a cradle-to-gate model to estimate the carbon intensity of various dairy products.
Two common units exist to compare the energy intensity of animal products: kg of CO2e per product weight or kg CO2e per protein content. The latter unit doesn’t enable adequate comparison for most dairy products, as some of these products have a very high fat content and aren’t necessarily consumed for their protein content. The former unit was used in the study as a result.
The key outcomes of the study were that the carbon footprint of most dairy products ranged between 1 and 3 kg CO2e/kg of product except for cheese (5.3 kg of CO2e/kg), butter (7.3 kg of CO2e/kg), and milk powder (10.1 kg of CO2e/kg). The results Canada-wide largely depend on farm practices and environmental conditions, such as climate.
To be able to make a comparison with beef, in (5), the authors calculated that the GHG intensity of cattle was 10.37 kg CO2 equiv./kg live-weight across Canada. Assuming that half of the weight of a living cow can be used for consumption, the total energy intensity of beef in Canada would therefore be 20.74 kg of CO2e/kg of product, which is twice the amount of milk powder production.
In 2018, emissions from livestock digestion (enteric fermentation) accounted for 41% of total agricultural emissions (6). Digesting cows emit methane which is 84 times more potent than carbon dioxide. In 2017, about 20% of the cows living in Canada were dairy cows.
Though the research I have listed here does seem to back up my boyfriend’s claim that emissions from dairy production today don’t nearly equate the ones from meat production, it still constitutes a substantial contributor overall in the agricultural processes. More studies and food intake surveys are required in a Canadian context to truly grasp the energy intensity of a non-vegan diet which includes many derivatives from milk ingredients in processed foods.
To sum up for my vegetarian friends in Canada, going completely vegan will likely cut down your emissions by 10%. 100% worth it!
(1) Per capita meat consumption in Canada by type 1998–2018, Statista. Available at: https://www.statista.com/statistics/442461/per-capita-meat-consumption-by-type-canada/
(2) Scarborough, P., Appleby, P.N., Mizdrak, A. et al. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK. Climatic Change 125, 179–192 (2014). https://doi.org/10.1007/s10584-014-1169-1
(3) Anastasia Veeramani, Goretty M. Dias, Sharon I. Kirkpatrick,
Carbon footprint of dietary patterns in Ontario, Canada: A case study based on actual food consumption, Journal of Cleaner Production 162, 1398–1406 (2017). https://doi.org/10.1016/j.jclepro.2017.06.025
(4) X.P.C. Vergé, D. Maxime, J.A. Dyer, R.L. Desjardins, Y. Arcand, A. Vanderzaag, Carbon footprint of Canadian dairy products: Calculations and issues, Journal of Dairy Science, Volume 96, Issue 9, 6091–6104 (2013).
(5) X.P.C. Vergé, J.A. Dyer, R.L. Desjardins, D. Worth, Greenhouse gas emissions from the Canadian beef industry, Agricultural Systems, Volume 98, Issue 2, 126–134 (2008). https://doi.org/10.1016/j.agsy.2008.05.003
(6) Greenhouse gas sources and sinks: executive summary 2020. Government of Canada. https://www.canada.ca/en/environment-climate-change/services/climate-change/greenhouse-gas-emissions/sources-sinks-executive-summary-2020.html