Subscribe to the Open the Future feed
The Footprint of a Cheeseburger (Updated!) (Updated Again!)
Please read the updated and complete version of the cheeseburger footprint story, found here.
I wondered a couple of days ago what the carbon footprint of a hamburger might be. It's the kind of question we'll be forced to ask more often as we pay greater attention to our individual greenhouse gas emissions. Burgers are common food items for many people; it's said that the average American eats three burgers per week, or about 150 burgers per year. What's the global warming impact of all that? I don't just mean cooking the burger; I mean the gamut of energy costs associated with a hamburger -- including growing the feed for the cattle for beef and cheese, growing the produce, storing and transporting the components, as well as cooking.
The clues provided by my friends Martin Kelly and Kim Allen sent me looking in the right direction, but then I stumbled across an absolute treasure: Energy Use in the Food Sector (PDF), a 2000 report from Stockholm University and the Swiss Federal Institute of Technology, looking at the life cycle energy use associated with... a cheeseburger! This highly-detailed report covers the myriad elements going into the production of the components of a burger, from growing and milling the wheat to make bread, to feeding, slaughtering and freezing the cattle for meat -- even the energy costs of pickling cucumbers. The report is fascinating in its own right, but it also gave me exactly what I needed to make a relatively decent estimation of the carbon footprint of a burger.
Based on a variety of sources, the researchers conclude that the total energy use going into a single cheeseburger amounts to somewhere between about 7 and 20 megajoules -- the range comes from the variety of methods available to the food industry.
The researchers break this down by process, but not by energy type. Here, then, is my first approximation: I split the food production and transportation uses into a diesel category, and the food processing (milling, cooking, storage) uses into an electricity category. Split this way, the totals add up thusly:
Diesel -- 4.7 to 10.8 MJ per burger
Electricity -- 2.6 to 8.4 MJ per burger
With these ranges in hand, I could then convert the energy use into carbon emissions, based on fuel. For electricity, I calculated the footprint using both natural gas and coal; if you're lucky enough to have your local burger joint powered by a wind farm, you can drop that part of the footprint entirely.
Diesel -- 90 to 217 grams of carbon per burger
Gas -- 37 to 119 grams of carbon per burger
Coal -- 65 to 209 grams of carbon per burger
...for a combined carbon footprint of a cheeseburger of 127 grams of carbon (at the low end, with gas) to 426 grams of carbon (at the high end, with coal). Adding in the carbon from operating the restaurant (and driving to the burger shop in the first place), we can reasonably call it somewhere between a quarter-kilogram and a half-kilogram of carbon emissions per cheeseburger. (But see below...)
Or, over the course of a year, between 37 and 75 kilograms of carbon emissions from the average American's cheeseburger habit.
If each of the 300 million Americans hit that "average" burger consumption, we're looking at 75,000-150,000 tonnes of atmospheric carbon annually from burger consumption alone -- that's the equivalent of the annual carbon output from 7,500-15,000 SUVs.
[But see below...]
(Update: I was reminded in email (thanks, Geoff!) that this should also include the methane emissions from cattle. So, let's add that.)
A typical beef cow produces approximately 500 lbs of meat for boneless steaks and ground beef. By regulation, a beef cow must be at least 21 months old before going to the slaughterhouse; let's call it two years. A single cow produces 114 kilos of methane per year in eructations and flatulence, so over its likely lifetime, a beef cow produces 228 kilos of methane (not including the methane from its manure). Since a single kilo of methane is the equivalent of 23 kilos of carbon dioxide, a single beef cow produces 5244 CO2-equivalent kilograms of methane over its life. If we assume that the typical burger is a quarter-pound of pre-cooked meat, that's 2,000 burgers per cow. Dividing the methane total by the number of burgers, then, we get about 2.6 CO2-equivalent kilograms of additional greenhouse gas emissions from methane, per burger, or about 5-10 times more greenhouse gas produced from cow burps than from all of the energy used to raise, feed or produce all of the components of a completed cheeseburger!
At 2.85-3.1 kg of CO2 (equiv) per burger, then, that's 428-465 kg of greenhouse gas per year for an average American's burger consumption.
(Second Update: More details on methane output from ruminants like cattle, courtesy of the EPA. The government estimates for methane output from "enteric fermentation" is a bit lower than the number cited in the Telegraph article, but when we add in the methane from manure -- which is about a third of that from cattle gas -- the overall numbers I've used still roughly work out.
And to add the necessary correction: adding in the methane, the overall CO2-equivalent emissions from all the cheeseburgers consumed in the US (assuming the average of 3/person is accurate) roughly equal the greenhouse output of 100,000 SUVs.
Obviously, these are all estimates, and will vary considerably by individual cow, feed type, and other environmental conditions -- but assuming my sources are correct, these methane outputs should be roughly accurate, enough to trigger a good conversation, at least.)
Comments
Does this include paper products associated with the burger--napkins, wrapping, bag? What happens if you have "fries with that?" Or a Coke? Fast food could be destroying the ecology in, oh, so many ways.
Posted by: Jacqueline Cascio | December 23, 2006 11:36 AM
Well - the napkins are where one should scribble the life cycle bistro-math. Of course, this can confuse things immensely, if eating said cheeseburger at the same time...
nice article in a tangent sense at National Geographic this month. Brazil cast as a pie chart, and mostly the empty quarter is full of cows.
Posted by: Jon S. | December 24, 2006 1:07 AM
It's all about Morningstar Farms textured protein BBQ ribs, lol. ;)
Posted by: Michael Anissimov | December 24, 2006 9:49 AM
This is exactly the sort of thing I was thinking about with my "fully loaded cost" response to the one-sentence challenge.
I wonder how hard it would be to make a simple reference table for the 20 most popular foods. Is it mostly just legwork collecting the numbers?
Posted by: jet | December 24, 2006 10:51 AM
Unfortunately we cannot ignore the effects of the manure, either. If anything it is a worse environmental problem than emitted methane, sustainability-wise.
Posted by: Howard | December 24, 2006 6:50 PM
Looking at what what we're eating, and making some adjustments, holds promise of making significant improvements in energy efficiency. Read more here.
Posted by: Craig Mackintosh | December 27, 2006 9:52 AM
It's hard to ignore these hard facts, especially coming from the United Nations -- the severe ecological destruction caused by factory farming is simply undeniable. One of the most important actions we, as individuals, can take to protect the planet is to choose vegetarian foods. You can get free information, including a starter guide, about veg eating at www.TryVeg.com.
Posted by: Katrina | December 27, 2006 10:16 AM
The methane from of the cow (and manure) must come originally from the grass it eats, thus it is part of a cycle. I'm not sure of how this cycle works as the grass takes in CO2 and the result is Methane, but it still seems to me that this isn't the same as CO2 from a fossil fuel that is dumped into the atmosphere.
Posted by: Mal | December 28, 2006 3:55 PM
You're right to identify the switch from CO2 to methane as critical issue in the carbon cycle question. Methane is more effective a greenhouse gas, over a shorter time-frame, than CO2; the global warming impact of the carbon as methane is much greater than the impact of the same amount of carbon as CO2.
Posted by: Jamais Cascio | December 28, 2006 4:01 PM
Another very important factor is deforestation. The cutting down of forests and rainforests to open up land for cow pastures is one of the key contributors to climate change (as well as to species loss).
You will need to figure out:
1) how much land each cow needs
2) how many trees need to be cut down to open up that land
3) how much CO2 is released into the atmosphere from cutting down those trees (which are often burned, but even if not burned, release CO2 when they decompose)
4) how much CO2 will no longer be "breathed in" by those trees that no longer exist
See the link below for more info on this and other issues related to livestock:
http://www.virtualcentre.org/en/library/key_pub/longshad/A0701E00.htm#sum
Posted by: D Miller | December 28, 2006 11:03 PM
This is all very well and good but pretty meaningless because what is the tradeoff? How much carbon would an alternative diet release? It's not like if we stop eating cheeseburgers then 465 kg of CO2 per person won't be produced.
Posted by: DigitalDjigit | December 29, 2006 6:52 AM
I make a great hamburger. I form a 3oz patty from bround chuck (special request to the butcher to trim most of fat) probably 97% lean. I can't get this at the local burger shack so my carbon footprint for the homemade burger is much less than eating out.
Posted by: Russell E Clark | December 29, 2006 10:38 AM
I applaude your efforts to study the footprint of a cheeseburger. You have initiated a HUGE topic with many facets, as your posters have raised. In response to the postings by Katrina #1 and Craig: If you are really motivated by the UN report and working toward healing this planet, don't stop with a pat on the back for being vegetarian... the dairy industry is responsible for much more damage to the planet and to the lives of the animals than the beef industry. Read this link to gain more clarity....
http://www.factoryfarming.com/dairy.htm ... then GO VEGAN
Posted by: katrina #2 | January 3, 2007 12:00 PM
Thanks Katrina #2 - I agree, which is why I went vegan almost 20 years ago. But, it's hard enough to get people to slow down on the meat, so I try to start there... :o)
Posted by: Craig Mackintosh | January 3, 2007 12:46 PM
I understand part of the cattle emissions problem has to do with their (feed-lot) diet of grain, rather than their natural diet of grass. This has been mentioned by advocates of grass-fed beef. While I've been a vegetarian for most of my 54 years, I think there may be a niche for cattle raised on grassland otherwise unfit for other produce.
Posted by: Michael O'Hara | January 3, 2007 1:32 PM
Nice calculations. However, it would be even more valuable if it were compared with alternative foodsources. Hypothetically, it could be that per calory foodintake a hamburger is less straining on the environment than the same amount of energy from, say... lettuce (I dont think it is, but the way the figures are presented here..they do not mean much, let's show an example to proof my point: the price is US$10. What does that mean? It means nothing without reference point. For a new car, it would be cheap, but the same US$10 for a chewinggum would be expensive. Putting the figures above in perspective would do a lot of good, in my humble opinion.
Posted by: Jeroen | January 6, 2007 5:46 AM
Hello from Western Australia. An interesting article but I agree with the suggestions about a framework of comparisons and trade-offs for alternative diets. I would also like to see a comparison of a typical diet (with all the health impacts of overconsumption of poor nutrition foods) and a 'good' diet.
Posted by: Martin Taylor | January 7, 2007 8:40 PM
I had an idea, an idealistic idea, an applicable idea, (though costly in application) that you could drain the atmosphere of carbon dioxide, convert the gas straight to a form of artificial but tasty beef substitute and therefore take care of a nice percentage of global warming and satisfy the desire of a beef hungry populous simultaneously. Call me crazy if you like but this idea still stands after 16 years.
Posted by: Simon Vermes | January 13, 2007 1:53 PM
Assume 1). The calculation is correct, 2).Per capita CO2-equivalent emissions for all food consumption is 10 times of that 3-burger benchmark (can't be more even for fatty Americans, right?). Then the annual total CO2-equivalent emmissions for food is 10*100,000 =1,000,000 SUVs. How many SUVs are out there? We really can care much less how many CO2 are from eating and care much more about how our exhaust pipes.
Posted by: william | February 24, 2007 1:58 PM
Hi... great stuff. I was able to get other rough figures from the internet.
a car emits about 2000kg/ year of CO2, while a human about 360kg/year.
Can you tell me how much CO2 gas is in 1 l carbonated drink?
Posted by: andrew vecsey | March 10, 2007 1:58 AM
very interesting about burgers, my interest was aroused by my wifes makeup cabinet, i wonder what the carbon footprint is of all the makeup that is used creme on, creme to take it off, eye shadow, liner, lash 'stuff' every one with 10 to 100 different types, styles, colours. Huge multi coloured containers for minute quantities of 'stuff'. hairdressing? shampoo dyes bleaches all going down the drain, plastic curlers fabric curlers, clips beads bangles. then get onto purfume, huge prices for huge bottles of never useable liquid, advertising design manufacture transport. nail varnish a million colours all in highly decorated bottles that 'never' get used up, removal solvents? I would lurve to see the carbon footprint of all that 90% uneccessary stuff. please please someone find out!
Posted by: David Key | August 7, 2007 10:16 AM
Great article. For more info on all kind of foods and their evironmental impact, see Online calculator (only in German):
http://www.ulme.ethz.ch/
And accompanying article:
http://www.esu-services.ch/download/jungbluth-lca_5_143_144.pdf
Eat vegetarian!
Posted by: Stefan | September 27, 2007 8:17 AM
LOVE the debate.
any way to clarify some facts?
Average human Co2 stated above at 360kg per person per year this has maths for 146kg/year
http://www.abovetopsecret.com/forum/thread278647/pg1
Now back to the Cows... they graze on ?? acres for year which REDUCES their Co2 impact by ??? help! whats the Cos absorbed by 1 acre grass per annum....
Posted by: Allmec | June 4, 2008 2:43 PM