Red Meat May Not Be as Bad for the Climate as We Thought (But it's Still Bad)

But that doesn't mean that meat's back on the menu, boys.

No it isn't
No it isn't.

American Meat Institute 1947 

One of the core tenets of living a low-carbon lifestyle is to give up red meat. We have noted before that it has ten times the greenhouse gas emissions of the same amount of chicken, fifty times as much as plant-based meals. I have been trying to live a 1.5-degree lifestyle, measuring the carbon emissions of everything I do, and on my spreadsheet, a single serving of red meat is 7200 grams of emissions, bigger than my entire day's budget.

But those emissions are not Carbon Dioxide; they are CO2 and CO2-equivalents, other greenhouse gases like methane and Nitrogen Oxide. Methane, produced through the digestion of plants by ruminant animals like cows and sheep, is considered by the IPCC to have a Global Warming Potential (GWP) of 28 times the warming impact over 100 years of the same amount of CO2.

Methane Doesn't Hang Around Like CO2

But does it really? Hannah Richie and her gang at Our World in Data at Oxford University (and my favorite source of current data) recently had another look at this issue, and remind us that while methane has a big impact in the short term, it is not a long-lasting greenhouse gas and decays in about ten years, unlike CO2 which hangs around for centuries. Richie writes:

Methane’s shorter lifetime means that the usual CO2-equivalence does not reflect how it affects global temperatures. So CO2eq footprints of foods that generate a high proportion of methane emissions – mainly beef and lamb – don’t by definition reflect their short-term or long-term impact on temperature.
emissions without methane
Red bar shows emissions without methane.  Our World In Data

Richie redoes the chart of emissions from various foods to separate the methane from the CO2 emissions so that we can treat the methane differently, which makes some sense; writing in Carbon Brief, Dr. Michelle Cain suggests that as long as a herd of cows stays roughly the same size, then the amount of greenhouse gas equivalents is not increasing, so it is not adding to the greenhouse gas burden in the atmosphere. "If the herd remains the same size with the same methane emissions every year, it will maintain the same amount of additional methane in the atmosphere year on year."

Others (I apologize, I cannot find the reference) have suggested that since the cows created the methane from eating plants which had stored Carbon Dioxide, then it shouldn't be counted at all, just as many (not here at Treehugger) claim that burning biomass like wood pellets is carbon neutral.

meme from Lord of the Rings
meme from Lord of the Rings. Via Reddit

But none of this puts meat back on the menu, boys, as the Lord of the Rings meme goes. Hannah Richie notes that land is still being cleared for livestock, it still takes a huge amount of water, we still have an antibiotic crisis, and as The World in Data chart shows, red meat still has a huge impact, with emissions from "land use changes; the conversion of peat soils to agriculture; the land required to grow animal feed; the pasture management (including liming, fertilizing, and irrigation); and the emissions from slaughter waste." There is also Nitrous oxide from manure and from the gas used to run equipment or transport. Richie writes:

Although the magnitude of the differences change, the ranking of different food products does not. The differences are still large. The average footprint of beef, excluding methane, is 36 kilograms of CO2eq per kilogram. This is still nearly four times the mean footprint of chicken. Or 10 to 100 times the footprint of most plant-based foods. 

I have never been crazy about comparing foods by CO2 per unit weight; eating a kilo of lettuce is a very different thing than eating a kilo of steak. I have used Our World In Data's chart showing CO2 per thousand calories, and now Richie lets us compare greenhouse gas emissions per 100 grams of protein:

gas emissions per 100 grams of protein
gas emissions per 100 grams of protein. Our World In Data 

Richie concludes:

The results are again similar: even if we excluded methane completely, the footprint of lamb or beef from dairy herds is five times higher than tofu; ten times higher than beans; and more than twenty times higher than peas for the same amount of protein. The weight we give to methane matters for the magnitude of the differences in carbon footprint we see between food products. However, it doesn’t change the general conclusion: meat and dairy products still top the list, and the differences between foods remain large.

No, Meat's Not Back on the Menu.

My vegetarian colleague Melissa Breyer would also remind us that the problems with meat go way beyond just carbon emissions; she has written that Even Eating a Little Red Meat May Increase Risk of Death and Katherine Martinko reminds us of the ethical red flags involved with eating meat or dairy.

And as Hannah Richie notes, it doesn't change the conclusion: eating red meat is still inconsistent with living a low-carbon lifestyle, and it still blows my budget. It's still off the menu.