by Marion Nestle
Dec 22 2009

Eating Liberally: Are pets responsible for climate change?

It’s been quite a while since Eating Liberally’s kat had a question for me, but this one certainly got my attention.  My book about pet food with Malden Nesheim, Feed Your Pet Right, has just progressed past its second set of page-proof corrections and is slowly making its way to publication on May 11.  Here’s her question:

Let’s Ask Marion: Is Fido The New Hummer?

Submitted by KAT on Tue, 12/22/2009 – 8:13am.

(With a click of her mouse, EatingLiberally’s kat corners Dr. Marion Nestle, NYU professor of nutrition and author of Pet Food Politics, What to Eat and Food Politics.

Kat: Dog lovers are howling over a new book called Time to Eat the Dog: The Real Guide to Sustainable Living. The book claims that “the carbon pawprint of a pet dog is more than double that of a gas-guzzling sports utility vehicle,” according to a report from the Agence France Presse.

The book’s authors, Robert and Brenda Vale, sustainable living experts at Victoria University in Wellington, New Zealand, estimate that a medium-sized dog’s annual diet–about 360 pounds of meat and 200 pounds of grains–requires roughly double the resources it would take to drive an SUV 6,200 miles a year.

You’ve become an expert on the pet food industry in recent years with Pet Food Politics: The Chihuahua in the Coal Mine, and your upcoming book, Feed Your Pet Right. So, what’s your take on the Vales’ claims? Is Fido really the new Hummer?

Dr. Nestle: Since Mal Nesheim is my co-conspirator on Feed Your Pet Right, this response is from both of us. Hence, “we.”

We ordered this book through Amazon in the U.K. but it is taking its own sweet time getting here. So all we really know about what these authors say is what we read in the October 24 New Scientist, which not only reviewed the book (in an article titled, “How green is your pet”) but also ran an editorial that begins, “If you really want to make a sacrifice to sustainability, consider ditching your pet – its ecological footprint will shock you.”

Oh, please. We don’t think so for two reasons, one quantitative, one qualitative. First, the quantitative:

The New Scientist review says:

To measure the ecological paw, claw and fin-prints of the family pet, the Vales analysed the ingredients of common brands of pet food. They calculated, for example, that a medium-sized dog would consume 90 grams of meat and 156 grams of cereals daily in its recommended 300-gram portion of dried dog food. At its pre-dried weight, that equates to 450 grams of fresh meat and 260 grams of cereal. That means that over the course of a year, Fido wolfs down about 164 kilograms of meat and 95 kilograms of cereals.

We don’t really have all the facts at hand. We have not seen the book, we don’t know what assumptions the authors made, and we can’t be certain that the review quotes the book accurately. Still, we are puzzled by these figures.

By our estimates, an average dog does indeed need about 300 grams of dry dog food a day; this much provides close to 1,000 calories. Fresh meat supplies about 2 calories per gram, so 450 grams would yield about 900 calories. Cereals have less water so they are more caloric; they provide nearly 4 calories per gram. The 260 grams of cereals would provide nearly 1,000 calories. If New Scientist got it right, the authors of the book are overestimating the amount of food needed by dogs by a factor of two.

On the qualitative side: Most dogs don’t eat the same meat humans do. They eat meat by-products—the parts of food animals that we wouldn’t dream of eating. These are organs, intestines, scraps, cuttings, and other disgusting-to-humans animal parts.

We think pet food performs a huge public service. If pets didn’t eat all that stuff, we would have to find a means of getting rid of it: landfills, burning, fertilizer, or converting it to fuel, all of which have serious environmental consequences. If dogs and cats ate the same food we do, we estimate that just on the basis of calories, the 172 million dogs and cats in American would consume as much food as 42 million people.

But they don’t. They eat the by-products of human food production. If we want to do something to help reverse climate change, we should be worrying much more about the amount of meat that we ourselves are eating–and the amount of cereals we are growing to feed food animals–than blaming house pets for a problem that we created.

  • Kelly

    Even assuming that their numbers are correct, and that everyone feeds their pets high quality, human-grade foods (both of which are huge & variable assumptions), it seems like the authors are missing out on a pretty critical notion when it comes to pets vs gasguzzling SUVs: pets offer tangible health benefits to owners. The same cannot be said for most cars, SUVs or otherwise.

    So if you are going to actually look at a pet’s ecological footprint, it seems like you need to include not only what they eat and their general medical care, but the care, benefit, and potential reduction of their companion/owner’s own ecological footprint (at least when it comes to health and medication).

  • Mark

    Also, they state, “requires roughly double the resources it would take to drive an SUV 6,200 miles a year.” Why use the 6,200 mile amount? I’m more familiar with 10K, 12K or 15K miles being used as a standard miles driven per year benchmark.

    So they’re guilty of both overestimating the damage done by the average pet AND underestimating the damage done by the average SUV driver. Good job, guys.

  • Emily

    I’m bothered by the “ditch your pet” piece of advice, too. It sounds like they’re advocating leaving your companion animal by the side of the road! I think there’s more than enough of that going on in this economy for that not to come with a couple dozen caveats.

    National Geographic’s excellent Green Guide ( also offers good advice on more eco-friendly pet foods, including my chosen brand, Natural Balance.

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  • Besides, we love our animals. And, not to be too glib, but their carbon footprint is a lot less than the carbon footprint of our children. A whole lot less. So if we are looking at ditching as a viable solution …

    No, of course, we would not ditch either. The solution is certainly not to throw more away. Ever.

  • Cathy Richards

    Thanks for adding some clarity to this discussion Marion. Of course we need to be wise consumers for our pets, as we are for ourselves and our children.

    There’s also the fact that pets enhance our lives, make us happier, keep us home more, going for walks more, etc. Those things are hopefully, somehow, indirectly responsible for a healthier planet.

    My friend’s ex-wife is a big PETA supporter. Which is good. But, she’s also gone public with her choice to not have children for green and PETA reasons. Okay….so if everyone makes that choice, very likely the planet will be healthier in 100 years — that whole “when we are gone” theory of earth’s recovery. But if only thoughtful, caring people decide not to have children, so much for the gene pool that we leave in charge of the earth.

    I think my pet helps me care more for animals than I ever did before. And children help people care more for the earth. So it goes.

  • I was scrolling through your blog and loving it. And then, I scrolled back up to the top, read your name, and realized I recently heard you speak at NY’s Food and Climate Summit. With that being said, I am pleased that I happened to stumble across your blog!

    I definitely agree that before we even come close to blaming the food that our pets our eating, Americans as a whole need to take a look at their own diets. The corrupt meat industry that is feeding most Americans’ own diets is only providing the leftover scraps that are being used for pet food. Plus, most animals are biologically made to eat meat. Technically, humans are not.

  • Emily

    Whoops, typo on mine– it’s actually and the pet food info is here:

  • Joe Ward – JWtalks

    Hello Marion Nestle, – Just came across You and this site, and am pleased / interested. On the topic of – Pet’s Carbon Footprint’, – I was really placed in high thought mode. – As I never consider the CF of Pets. – Somewhat neutal is where I stand for now. But, find this very interesting, and as I said, thought provoking,- especially with the Green movement – Thank You for Your’ work and sharing. – Oh, by the way, I am a Dog lover,- but still an Independent. – Sometime this winter, I intend to read at least 2 of the following:- Pet Food Politics, What to Eat, and Food Politics. – Happy Holidays & a Great 2020! – Joe Ward (JWtalks) –

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  • cori

    I feed my dog USDA organic dog food. Ditching our pets is not a viable solution. Learning how to be responsible for where our food comes from is.

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  • Cindy

    Marion has a good point that our pets eat meat by-products, but where does the original meat come from? The industrially-produced meat we are eating. We all know that meat production is a significant source of environmental problems, and that we humans should be limiting our meat consumption (especially the meat with is factory farmed–small scale farming is something else) as a part of dealing with climate change, so our pets–whose consumption of meat help to make industrial meat production profitable, may be part of the problem (but as Marion notes, it sounds like there are problems with the math in the book noted).

    Sharon Asktyk wrote about this topic in November, and it is certainly worth reading for those with pets–or those concerned about factory farmed meat, climate change, etc:

  • Thank you for a wonderful response to a ludicrous accusation. Ironically, it is my pet that led me to become “greener” in the first place. My involvement in dog rescue started me thinking about animal welfare in general, which led to researching the issues of meat production in this country (which, I believe is how I stumbled across your blog), which has led to a drastic reduction in meat consumption in our household and a change in our diets. The meat that we do buy now is organic and humanely and locally produced.

  • JWtalks

    Hello, this is Joe Ward (JWtalks) again,- and would like to add:- many, so-called canine experts do not reallly understand the ‘real’ natural diet, thru evolution / Nature, is, for Dogs, mostly that of a carnivore, Yes. — BUT, ‘also’ as an omnivore / herbivore, etc.. When, I, as a researcher on dogs, and as a Traditonal Naturopath, Hygienist, Scientist, and Herbalist, have to ask You all why You would Not consider ‘Canines’ as more than just Carnivores. -Here we go:- In the wild, carnivores, including ‘wild dogs’, cats / canines kill and consume fresh live prey grazers. O’k. but, why do these Dogs, lions, etc.- animals, first try to get to and eat the intestines first? The innards, which are only partially digested are of utmost importance for Nutrition, assimilation of Vital nutrients, and survival. Most of the the animals sought, are grass, grain, and plant eaters. The Dogs digestive system can Not adequately digest / assimilate, or use, these grass ‘ grain plant types. – So they eat animals whom have already partially pre-digested these live whole plant foods, which they need also!! – That is why I include very important Herbs, Vitamins, Minerals, Omegas, Fatty-acids, etc.,- in the canine modulator formula for optimum health — ‘ReFidolize’. To assist the innate immune and digestive system of Dogs, to grow toward health, wellness, and freedom of Dis-ease, as “Nature”. intended, they eat mostly sheep, goats, cattle, rabbits, birds, deer, zeebra, rodents, etc! — Joe –p.s.–(yes-GREEN)

  • James

    I am also reluctant to condemn pets as large contributors to global warming when there are so many more obvious culprits, but I don’t like this peremptory dismissal of the pet opponents’ arguments. Is there really no other use for all of the meat and meat byproducts that go into pet food? I’m not an agronomist but I can think of a few: some could presumably be ground up into sausage, other parts could go to animals used for food (much as bycatch is used to feed carnivorous fish like shrimp) and still others can be rendered into fat used for a variety of other purposes such as gelatin and glue. Come on, Marion: you’re usually so careful! What’s with the flippancy?

  • Nurse in Md.

    It’s healthy to feed your dog or cat a “raw” carnivore diet anyway. Quit the dried & canned dog food! Go buy the “by-products” from the grocery store before they throw them away! It’s better for your pet’s teeth to eat raw flexible uncooked turkey or chicken neck bones, livers and gizzards, beef heart and tripe, than that weird rawhide stuff from Taiwan anyway! It’s gross looking, YES. But your pet will LOVE it, and your vet bills will be significantly lower, even though your vet will argue incessantly against it! Been there, done that, 5 years now, post mast cell cancer on cheek, post anal gland impactions, etc etc etc..happy healthy, oh, yeah, we did break a tooth on a giant sized bone- my fault, humorus bone from a lamb was way too challenging, left it to dry out for too long as well, dog cracked her tooth biting down on it!
    It was an expensive proposition to have oral surgery to have it removed, but dentist said her gums were great! he wanted her to stop the raw diet, go back to canned again…I way.. I would sacrifice another tooth before sacrificing her anal glands again(she was close to needing them removed!), or her general health..that’s a no-brainer!

    She’ looks like a dog 3-4 yrs old, she’s a 7 yr old black lab x energy like you wouldn’t believe!

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