A COMPARATIVE STUDY OF PLANT-BASED BURGERS AND MEAT BURGERS
With the rising concerns over climate change, the question that has risen to popularity is “what is my carbon footprint?” People want to know what the carbon footprint of the clothes they choose to wear is, what the carbon footprint of the electronics they us, the products they use and even the food they eat. It is well documented that the carbon footprint of producing meat for consumption is considerably higher compared to that of a vegetarian diet.
This article dives into the carbon footprint of America’s staple food: a burger. The scope of this article was to determine carbon emissions based on beef and veggie burgers consumed in an average year. The emissions factors used in the study are based on life cycle analysis of the main ingredients used for veggie patties and a life cycle analysis of producing beef. For more accurate results the emissions factors should also include the downstream processing of beef into a beef burger patty and processed vegetables into a veggie burger patty, along with additives that go into these patties with their corresponding carbon footprint. This will be considered in Scope 2 of the study to determine the carbon footprint of making a burger.
The plant based artificial meat alternatives are better for the environment in terms of carbon emission. As reported by the EPA, agriculture sector is the second largest carbon emissions contributor, encompassing 24% of the total carbon emissions in the United States, of which livestock has a heavier contribution.
Agricultural emissions include crop and livestock production for food. Upstream sources of emissions for crop production are application of fertilizers, irrigation, drainage of organic soils, and growth of nitrogen fixing crops. Whereas, upstream sources of emissions from livestock are enteric fermentation, which is the production of methane from the natural digestive process and manure management which produces methane and nitrous oxide.
Enteric fermentation represents over a quarter of emissions from the agricultural sector, while manure management accounts for 12% of the agricultural sector’s emissions depending on how the manure is treated and stored. One of the ways to mitigate emissions from livestock would be altering their diet and their manure can be better managed to produce renewable energy, however the impact from these will not be as significant due to the organic nature of the source of emissions.
Figure 1 shows a breakdown of upstream emission sources in agricultural sector from crop production and livestock based on 30 years of data reported to EPA.
Based on the average emissions reported for the last 30 years to EPA, overall production of crop clearly has a higher contribution to carbon emissions compared to livestock as illustrated in figure 1.
However, when production volumes are considered, the carbon footprint of producing one metric ton of meat significantly outweighs the carbon footprint of producing one metric ton of crop. Based on 2017 data summarized in Table 1, which is the most recent data for production volumes data available for meat and crop, one metric ton of crop produced emits 0.283 metric tons of CO2e into the atmosphere, while producing one metric ton of meat emitted almost 7 metric tons of CO2e into the atmosphere.
Table 1: Summary chart of 2017 for crop and livestock carbon footprint per metric ton of unit produced.
So, one metric ton of crop production has a 95% lower carbon footprint compared to producing the same volume of meat. Of course, this data set is all inclusive, it includes all crops and animals that are consumable. However, not every crop produced is used to only make veggie patties, and not all livestock will produce a beef patty.
So, to determine carbon footprint of producing beef for a beef patty versus a veggie patty, granularity in livestock data was achieved to include only cows and the crop production to include only Barley, Corn and Soybeans, which are few of the main ingredients of a veggie burger. Veggie patties are made of a large variety of veggies but these three were chosen due to data availability reasons.
A life cycle carbon footprint analysis, summarized in Table 2, by Tristram O. West and Gregg Marland determined the carbon footprint from production of crops like barley, corn and soybeans amongst others. The study considered emissions from fertilizers, fuel consumption, electricity and the processing of grains and finally, transportation. A separate study by Raymond Desjardins-et-al., which considered a life cycle carbon footprint analysis for beef cattle is also summarized in Table 2. Beef emissions factor takes into account the lifespan of beef cattle and resulting emissions till it is slaughtered and processed.
Table 2: Emissions Factors determined for the top ingredients in beef and veggie burger patties based on life cycle carbon emissions studies
According to beefboard.org, in a given year Americans consume approximately 50 billion beef burgers while Beyond meat and Impossible Burgers estimate the annual consumption for veggie patties is around 228 million burgers. Based on these estimates, an assumption on the weight of an average patty and the emissions factors from table 2, a total carbon emission was calculated from the consumption of beef and veggie burger patties in a given year as summarized in Table 3.
Table 3: Total CO2e emissions from the consumption of beef and veggie burger patties
The difference in CO2e emissions from consumption of beef patties versus veggie patties is significant. The carbon emissions from beef patties is 99.87% and that of veggie patties is 0.13%, however the consumption of beef patties is much larger too. In comparison, the carbon emissions from total livestock production is 96% and 4% for total crop production even though crops are produced at higher volumes than livestock, as illustrated in Figure 2,
This study does not take into account the carbon footprint of downstream processing of the meat or veggies into patties, or the carbon footprint of any other ingredients or additives. Processing a veggie burger requires a lot more ingredients compared to a beef patty; the individual processing of these ingredients and their transportation could potentially balance out the total emissions from burger consumption.
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References:
1. Raymond L. Desjardins, Devon E. Worth, Xavier P. C. Vergé, Dominique Maxime, Jim Dyer, Darrel Cerkowniak, “Carbon Footprint of Beef Cattle”, Sustainability 2012
2. Tristram O. West∗, Gregg Marland, “A synthesis of carbon sequestration, carbon emissions and net carbon flux in agriculture: comparing tillage practices in the United States”, Agriculture, Ecosystems and Environment.
3. CHG Emission Data EPA: https://cfpub.epa.gov/ghgdata/inventoryexplorer/#iagriculture/allgas/souce/all
