Study Finds Meat and Dairy Create More Emissions Than Miles
by Eliza Barclay, Washington, D.C. 
on 05. 9.08
A study in the April 15 edition of Environmental Science & Technology by the prolific Carnegie Mellon University researcher Christopher Weber found that food transport accounts for only 11 percent of food-associated greenhouse gas emissions, while production contributes a whopping 83 percent. Specifically, nitrous oxide and methane -- mainly byproducts of fertilizer use, manure management and animal digestion -- make up a far bigger piece of the emissions pie than emissions from transporting our food from faraway places, the study found.
Weber and colleague Scott Matthews conducted a life-cycle assessment of greenhouse gases emitted during all stages of growing and transporting food consumed in the U.S. (using Department of Commerce data) and calculated that the average U.S. household generates 8.1 metric tons (t) of greenhouse gases (in CO2 equivalents) annually as a result of food consumption. By comparison, driving a car that gets 25 miles per gallon of gasoline for 12,000 miles per year (the U.S. average) produces about 4.4 tons of CO2.
Even more surprising, the study noted that U.S. consumers can do more to reduce greenhouse gases by eating one-seventh of a week’s calories from chicken, fish or vegetables instead of red meat or dairy than buying all local foods.:: Via Science News
Photo credit: DEA/P.MARTINI/Getty Images
See also a recent study by Weber on Outsourcing Global Warming.
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I consider myself and others who live in my area of the country blessed then. Many people here get locally grown organic vegetables, fruits, and meats. The mass meat industry is gross. If only people stopped eating so much meat and dairy!
I agree with the thrust of the study, but wanted to point out a couple things --
1. They compared household consumption of food to driving one car. A good portion of households have 2 cars, which would make the carbon footprint of driving equivalent to eating. An better way to look at this would be to say a household's eating habits equals about 22,000 miles of driving. Cutting your household's driving in half would make a big contribution as well.
2. Converting everyone from red meat to fish (as if that were even possible) would create its own set of problems. With overfishing already a problem, not to mention dredging and the introduction of non-native species, eating fish isn't a simple solution.
Finally, I would be interested in knowing how organic dairy products help the situation. I'm a vegetarian, but just can't give up milk and cheese, and I don't imagine we'd ever convince most of America to do so either. To what extent do organic dairy products help reduce the carbon footprint / other pollution?
also, not feeding animals by-products of other animals would help greatly.
and did they even consider what happens to that food as it's being shipping all over the world? Certainly eating locally -- from a reputable source -- is worlds better than leaving your health in the hands of chemists who inject pesticides directly into the crops.
Live in cities, use the public transportation, buy fruits, vegetables and grain at the farmer's markets. Seems like a no-brainer to me.
Great post!
There isn't a percentage for how much is generated from feeding animals other animal by-products so all the assumptions made below are part on that basis and what I read here. You can happily fill me in on where I went wrong :)
So 8.4 tons eh? For a whole family? (probably 4 I'm guesing)
And ~80% of that comes from various by-products, like basic functions to live? It seems to me unless you just killed all the animals you're going to have these problems regardless. That would usually make the miles MUCH higher on the carbon chain, especially considering meat can be shipped from over 100 miles away in some areas (you'll total up 12,000 in no time with 100 per meat popsicle).
I'll also assume this isn't addressing the non-issue of locally grown, grass fed, humanely raised meat. I have a farm that grows local in my area with just that in mind.
Overall, I can't see cutting meat out altogether based on current data, reducing yes but not cutting it out, especially considering my sources are rather "green". That and meat is just so tasty and scrumptious. Mmmmm :)
It's often the simple things we can do that will have the biggest impact. Eating locally not only cuts emissions, it supports local families and businesses. It's a win-win-win. (You, your 'hood and the earth)
Previous commenters pinned this one easily: use alt transport (including walking) every possible chance, buy local, at farmers markets and/or grow your own food and eliminate meat & dairy from the diet.
The book "Diet for A New America" gave me the original clue that being vegetarian wasn't just an ethical decision. And this latest news just confirms what we knew all along.
that is why going vegetarian
is the way to go green
The study is flawed because it counts CO2 equivalents of methane and nitrous oxide which have an atmospheric lifetime of only 10-15 and 120 years respectively while CO2 has a lifetime of several tens of thousands of years.
This means that after rime the 8.1 tons of CO2 equivalent from meat and dairy farming will decrease while the 4.4 tons of CO2 generated from your average car will still be the same for tens of thousands of years.
Of course it still isnt good that meat and dairy farming polutes but one must take into account the time factor in such a study before comparing it to transport as when you look at this some will think we should rather be careful of the farming then the transport.
Conclusion: Transport is far worse then farming even though on the short term it looks like the opposite.
As others have pointed out, the article incorrectly compared automobile emissions to food emissions.
It also did not compare full lifecycle emissions from the operation, manufacturing and storage of automobiles.
Emissions during the manufacture of an automobile are typically equal to around 20% of the operating emissions.
Each automobile requires road space to operate and at least 3 parking spaces; one at home; one at work and one at shopping. If the spaces are in a parkade, significant emissions occur in the construction. If the spaces are surface lots, they decrease the land that can be used by vegetation to sequester.
Road and bridge construction causes significant GHG emissions as well.
Food is far more critical to survival than an automobile.
Just goes to back up the other studies showing that cutting animal products from your diet is a better choice for environmental sustainability. You can hem and haw all you want, but NO ONE needs to eat meat - its a personal lifestyle choice. In that light, meat eaters are somewhat akin to people who drive SUVs...you know better, but you still choose it anyways.
Glad to see dairy lumped in with meat as major contributor to global warming. Even organic, grass-fed dairy is not a solution for tons of reasons, including the fact that grassfed cows emit 4 times as much methane as grain-fed cows.
I disagree that switching from red meat to fish is a good idea, since geophysicists Eshel & Martin published a U. of Chicago study in 2006 reporting that a fish-based diet is as bad as a red meat-based diet. The commercial ocean fishing industry emits ton of CO2 in fossil fuels, and salmon farms are extremely inefficient.
The more we move away from an animal-based diet and towards a plant-based diet, the better...
The modern diet, or vegan diet, was the best thing that I ever did! I encourage the skeptics to give it a try. Everytime I sit down to eat a delicious vegan meal I feel so good that not one animal was abused or slaughtered. All life deserves dignity and respect and it is about time that we are beginning to give it. If we could just now work on getting animals out of the umbrella of the Deptartment of Agriculture! A sentient creature should not be tossed around like a head of lettuce nor should they be confined to a cage for their entire lives.
One more thing ... There was a comment about not being able to give up dairy products. I thought the same thing at first but when I realized what happens to the animals at the dairies (male calves are taken from the mothers and sent to veal farms, after years of abuse dairy cows do not retire but are sent to stockyards to be sold and slaughtered as low grade meat- the downed cows in the recent news...), and also learned what dairy products actually are, that made me decide to avoid it. There are many products like Tofutti, nutiritional yeast, almond and soy milks that can help you with the change. Good luck!
The real point of this article is that if we're going to actually do something about global warming, we have to be smart about it, not just act on uninformed reflex.
I prefer to buy local, but's it's sobering to consider that the greenhouse gas cost of grain shipped half way around the world might be a lot less than the organic goat cheese made in my town.
I used to be a vegetarian, and now eat a low-meat diet (mostly chicken) but it looks like it's time to break out Diet For a Small Planet again (a great cookbook from Back in the Day that advocated food combining to high protein results from rice, beans and dairy).
wait...if i (and others) stop eating meat, it follows that the animal population will increase. and wouldn't more numbers equate to an increased carbon production, just by their very existence? and how will that [probable] overpopulation then affect the rest of the biological structure?
greenhouse gases are just 1 element of a whole-planet concern. i trust the elders; everything in moderation.
respect... balance...
wait...if i (and others) stop eating meat, it follows that the animal population will increase.
Sorry, doesn't stack up. If you and others stopped eating meat the animal population would likely go down, due to the decrease in farming of animals.
Yes, less meat means less animals raised for food.
But farm animals would be replaced by an increase in wildlife on the land no longer needed for agriculture. Much of this land could be returned to wilderness. While some natural grazing animals like Buffalo emit methane, it is more than offset by the carbon sequestered in the soil and plants that make up a healthy grassland wilderness.
The problem isn't dairy.
The problem isn't meat.
The problem is TOO MANY PEOPLE. Period. A plant based diet buys you only a little time, and allows you to ignore to problem of overpopulation until it is too late. Diversity in food source is a GOOD thing; vast monocultures of relatively few grain and bean staples is a good way to invite disaster.
Sustainable food production will never be possible with unsustainable population numbers. There is no easy fix via dietary switching.
And I'm unclear as to the utility of comparing transportation to food; they are not alternatives to each other. It just seems like time for us all to grow up and look at the big picture, instead of leaping to assumptions based on each new infonugget dribbled out in isolation. (Haven't we learned from the nutrition "science" of the last 20 years? Eggs good, bad, good, bad, now neutral. Fat good, bad, good, bad, now good and bad depending. Knee-jerk reactions enable these con-jobs to continue. Common sense and a long-term view is key, in my opinion.)