Last updated 1/10/20.
Should I stop eating beef? The details.
A study by Poore and Nemecek published in Science in 2018 looked at data from food production and consumption around the globe. The results led to numerous news articles, blog posts, and tweets. The work is quite comprehensive and detailed. One thing is clear though, even beef produced in the most environmentally friendly way, including with the lowest greenhouse gas emissions, creates more emissions, uses more land, and cause more of other environmental stress than even some of the most un-environmentally friendly produced pork, chicken, or even milk. Lamb is not always as bad as beef, but both beef and lamb are worse environmentally than other meats, so basically the conclusions for beef apply to lamb.
Drawing detailed conclusions about pork vs chicken etc. is hard, but it’s clear that as a group, other meat and dairy beats beef easily, and “beans (pulses) and grains” are significantly better for the environment than other meat and dairy.
A 2014 study by Eshel et al. focused on beef and other meat production in the U.S. Their work came to the same general conclusion: the consumption of beef has a significantly larger impact on the environment, including greenhouse gases, than other meats. (This study did not look at lamb.)
In 2016, an interesting report was put out by Waite et al. of the World Resources Institute. In addition to the usual greenhouse gas sources, they included what the cost in emissions was if you assumed that the land needed for beef was cleared from it’s natural state. That may seem odd, we have lots of pastures already. The argument though is that with the rise of beef eating in other countries will require the clearing of land if everyone tries to eat like we do in the U.S. Since beef is a global market, they reason it is fair to include the cost of clearing land. There analysis shows that the land-change needs of beef and lamb are far more than those for other meats, or plants, and the green house gas emissions related to the production of beef goes up by nearly a factor of ten as compared to other analyses.
Emissions calculation details
Suppose you ate one less hamburger each week (or it’s equivalent in tacos, meatballs, or a steak). That would be 52 fewer 4 oz burgers a year, which is 13 lbs (or 5.9 kg) of beef. Both the science papers discussed above work out how much CO2-eq emissions one can assign to a kilo of beef.
The calculation is complex, though. Some people calculate emissions per grams of protein others per gram of beef.
And cattle raise in Illinois versus Texas versus Japan can have very different impacts. So, while both papers seem reliable, their numbers vary. Poore and Nemecek’s result works out to about 75 kg CO2-eq per kg beef; Eshel et al. give 32 kg CO2-eq per kg beef.
So, giving up one burger a week for a year will save you 442 to 189 kg CO2-eq.
The average person in the U.S. eats 0.5 kg (about a pound) of beef every week.
What if they stopped completely? That is 26 kg of beef per year.
This would reduce their emissions by 1,950 to 832 kg CO2-eq per year, or 1.950 to 0.832 MT.
For comparison, the average CO2 emissions of a person in the U.S. is 16.2 MT. So, cutting out one hamburg a week would reduce the average person’s emissions by 1 to 3%. Cutting out beef entirely, would reduce this person’s emissions by about 5 to 12%