[Foodplanning] Feature: Estimating the Carbon Footprint of A Cheeseburger

[Ashwani Vasishth]

http://www.greenbiz.com/reference/webguide_record.cfm?LINKADVID=74669

The Footprint of a Cheeseburger
http://www.openthefuture.com/2006/12/the_footprint_of_a_cheeseburge.html

Writer Jamais Cascio wondered 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," he says. 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? Not just mean cooking the burger -- 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? Read this to learn 
more.

    * * *

http://www.greenbiz.com/frame/1.cfm?targetsite=http://www.openthefuture.com/2006/12/the_footprint_of_a_cheeseburge.html

The Footprint of a Cheeseburger (Updated!) (Updated Again!)

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) 
<http://www.infra.kth.se/fms/pdf/energyuse.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.)

Posted by Jamais Cascio on December 22, 2006 9:36 PM
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