You may have seen the meme circulating around the internet: some researchers from Australia New Zealand are claiming that owning a dog has as much impact on the planet as owning an SUV. I’ll let New Scientist summarize their case:
[A] medium-sized dog…consume[s] 90 grams of meat and 156 grams of cereals daily in its recommended 300-gram portion of dried dog food…So that gives him a footprint of 0.84 hectares…
Meanwhile, an SUV…driven a modest 10,000 kilometres a year, uses 55.1 gigajoules, which includes the energy required both to fuel and to build it. One hectare of land can produce approximately 135 gigajoules of energy per year, so the Land Cruiser’s eco-footprint is about 0.41 hectares – less than half that of a medium-sized dog.
It’s just the sort of counter-intuitive claim that gets lots of attention on the brave new internet era. So interesting! So science-y! So Twitter-able!
And yet, so false! Once you sniff around the numbers, it quickly becomes apparent that those researchers are barking up the wrong tree.
Let’s get one thing out of the way: I’m not a dog owner. Much to my kids’ dismay, I don’t even want a pet. Nor do I own an SUV. So, in theory, I…er…don’t have a dog in this fight. Still, this claim struck me as so wrong that it made the hair on my neck stand up. And I’d hate to have someone catch scent of this meme and conclude that buying an SUV is no big deal—“It’s not like I’m buying a dog or anything”—if the real numbers don’t support that conclusion. (That’s the risk of bad information: it can lead us to make choices that are in stark conflict with our values.)
So let’s paws for a moment, and see if this sleeping dog is actually a lie.
First, let’s look at that SUV. The calculations behind the internet meme say that it’s driven about 6,200 miles per year (10,000 km). And yet, according to the US Department of Energy, a real SUV in the US is driven an average of 13,700 miles annually. Already, the internet meme is off by a factor of roughly 2.2. I haven’t checked whether the 10,000 km figure is reasonable for Australia New Zealand—but when compared with typical US driving habits, their mileage assumption certainly skews the numbers in favor of SUVs, and against dogs.
And then there’s the total energy estimates. The pet-pessimists estimate that an SUV (in their calculations, a 4.6 liter Toyota Land Cruiser driven about 6,200 miles) consumes 55.1 gigajoules of energy in both fuel and amortized manufacturing energy every year. That, too, is low. A Land Cruiser gets about 15.25 mpg in combined city/highway driving—meaning that if it’s driven 10,000 km, it consumes about 407 gallons of gas, or 53.6 gigajoules worth of energy. But once I add in the energy used to produce that gas, along with what’s likely a low-ball estimate of the “embodied” energy from vehicle manufacturing, I get get about 74.9 gigajoules—44 percent more than the authors estimate. Yet again, they’ve low-balled the impacts of the SUV in a way that makes dogs look worse by comparison. (Here, I’m drawing from the data collection and calculations I did for our CO2-by-transportation-mode charts. And I’m looking only at energy, not at the additional climate and pollution impacts of emissions from tailpipes and smokestacks.)
So even before you start to look at dogs, the authors have underestimated the environmental impacts of SUVs by a factor of at least 3. And that’s not including the indirect impacts of SUVs—the parking spaces we build for them; the roads and bridges they drive on; the impacts of insurance and licensing operations; etc., etc., ad nauseum.
Then there’s flip side: the authors’ claims about the impact of feeding pets. The anti-doggists estimate it takes .84 hectares—or about 2.1 acres of cropland—to meet a a pooch’s food needs for a year. There are a little over 70 million dogs in the US (the Humane Society says 74.8 million, the veterinarians say 72.1 million, and the pet food industry says 66.3 million, for an average of 71.1 million canines). So by the authors’ estimates it must take about 150 million acres of US farmland to feed our dogs. In all, there are 440 million acres of cropland in the US—suggesting that the equivalent of one-third of all US cropland is devoted to producing dog food. [EDIT, Feb 17 2010: I’ve been informed that this paragraph is not accurate: the .84 hectares represents an estimate of the ecological footprint of a dog—which is a very different thing than the amount of land required to raise food for a dog. So for the time being, consider the cropland comparison moot.]
We use the equivalent of a third of all US cropland to feed dogs? That’s barking mad!
To see why it’s wrong, you can look from the bottom up, at the foods that dogs eat. Or you can look from the top down, at the aggregate sales of dog food vs. the entire agricultural economy. I’ll do both.
First from the bottom up: what, exactly, do dogs eat? The anti-pet-ites seem do a good job of calculating dogs’ calorie requirements. Canines wolf down a lot of food: a mid-sized dog consumes roughly 30 calories per pound of body weight per day. (Smaller dogs eat as many as 40 calories per pound of body weight, while larger dogs eat as few as 20 calories per pound. Call it the yapping-to-napping spread.) I couldn’t find the average weight of dogs in the US, but the median dog breed listed here has an adult weight of 47 pounds. If that’s representative of US dogs, then the average dog will eat 1,410 calories today, give or take—which, as I read it, is roughly what the authors’ figures imply.
So the real problem with the authors’ calculations isn’t with their estimates of how much each pet eats. It’s with this statement:
[A] medium-sized dog…consume[s] 90 grams of meat and 156 grams of cereals daily
Strike that: most dogs DO NOT eat meat and cereals. With a few exceptions, they eat “meat” and “cereals.” The “meat,” in particular, tends to be byproducts—things that people in the US simply won’t eat, even in hot dogs. Here’s one description of the ingredients in pet food:
The protein used in pet food comes from a variety of sources. When cattle, swine, chickens, lambs, or other animals are slaughtered, the choice cuts such as lean muscle tissue are trimmed away from the carcass for human consumption. However, about 50% of every food-producing animal does not get used in human foods. Whatever remains of the carcass—bones, blood, intestines, lungs, ligaments, and almost all the other parts not generally consumed by humans—is used in pet food, animal feed, and other products. These “other parts” are known as “by-products,” “meat-and-bone-meal,” or similar names on pet food labels.
Even the cereals dogs eat are often deemed unfit for human consumption. I’m not trying to gross you out here, or encourage you to feed choice cuts to your pooch. Instead, I think it’s probably a good thing that dogs eat things that humans won’t—since otherwise they really would be eating people food, which really would increase their environmental impact. But since most dogs get their calories and protein from the waste products of people food, the idea that the environmental impact of dog food is additional to the impact of human food is simply wrong.
Of course, that’s not to say that dog food has no environmental impact. Dog food, and meat byproducts generally, provide some financial contribution to the meat industry, and hence to the overall planetary impact of meat production. Dog food also also requires energy for processing, packaging, and transportation.
Yet when you look at pet food from a macro-economic perspective—that is, from the top down, rather than the bottom up —dog food is little more than a rounding error. Total retail food sales in the US topped $1.1 trillion in the US in 2008 (see table 36 from the USDA’s Agricultural Outlook statistics.) But according to the pet food industry, retail dog food sales totaled just $11 billion in 2008. By that measure, dog food represents about one percent of the total food economy.
Looking more narrowly at the economics of meat byproducts, I found these USDA estimates of meat “price spreads”, which show that meat byproducts are worth somewhere between 4 and 15 percent of the total value of livestock, depending on the year and the kind of animal. And obviously, dog food is only one of many uses of those byproducts—there’s also food for other pets, and a variety of industrial uses as well. So based on the economics, there’s just no way to attribute much of the impact of agriculture on our dogs.
In short, whether you go by the macro-economics, or by the actual constituent parts of dog food, there’s simply no principled way to say that the dog food has the same impact as human food. I’d be very surprised if ANY principled life-cycle assessment found that dog food has more than a small fraction of the overall environmental impact of US agriculture. My guess is that dog food accounts for a maximum of 5 percent of all US crop production, and possibly as little as 1 percent. That’s a far cry from the one-third that the authors imply.
Of course, dogs have indirect environmental impacts, just as SUVs do: veterinarians, energy for heating and cooling, the food calories that humans use while walking their dogs, etc. I won’t even try to tally them up, because there’s no real point. Just looking at the numbers so far—combining the underestimates of SUV impacts with the overestimates of dog food impacts—the anti-doggites are off by a factor of at least 18, and probably more.
But because I’m doggedly persistent, I’ll mention one final issue. The authors of the original meme estimate that:
One hectare of land can produce approximately 135 gigajoules of energy per year
I haven’t looked at the original book, so I have no real idea what this means. A well-located solar power installation can produce roughly 10 times that much energy per acre per year. Perhaps it’s got something to do with biofuels—maybe the net annual production of corn ethanol per hectare, after accounting for the energy for fertilizer, tractor fuel, and distilling. Yet having run the numbers before, I’ve concluded that there’s absolutely no way run the US SUV fleet—roughly the size of our dog population—on corn ethanol alone. There’s just not enough cropland in the country to do it. But obviously, we power our fleet of dogs (and cats and people and horses, etc.–and even some cars) fairly easily with the cropland we’ve got.
Let’s be clear—I’m not claiming that we should ignore the environmental impact of dogs. That’s one of reasons that I, personally, am reluctant to own one! But I think that making an empirical claim without doing solid research does a grave disservice to public discourse. Being wrong can have consequences—including, potentially, encouraging people to make the wrong choices, even if their heart is in exactly the right place.
So I say to the folks who made the original claim: Bad Researchers! Fur Shame!!! And to the rest of you: let’s consider the “dogs are worse than SUVs” meme debunked: buried in the back yard, put to sleep, and whatever other bad dog pun comes to mind.
Photo courtesy of Flickr user Mil under a Creative Commons license.
MvB
OMG, Clark! There’s so many doggy turns of phrase in here it makes my brain yelp. 😉 Hilarious.
bill
One could do a back of the napkin by calculating annual cost. How much would it cost to feed a dog vs how much would it cost to drive an SUV? Unfortunately there are lots of hidden subsidies for both food and gas but it helps with ballpark figuring. Dog (the average food costs is a penny per lb per day) = 1 cent * lb * day = .01 * 47 * 365 = $171.55SUV (13,700 miles per year at 15.25 mpg) = 13,700 miles / 15.35 mpg * $2.40 = $2156.06$177 vs $2156
Matt the Engineer
Yet another way to do the analysis: How many snickers bars would it take for Fido to get a bicycle (with many gears, built for a dog) up to 70 MPH, if pulling an SUV?
bigyaz
New Zealand, Australia, whatever. All those Down Under countries look alike.
OregonMichelle
Looking at the “by-products” that SUVs and dogs emit, clearly SUVs are easier to clean-up after, with cap and trade.With dogs it would probably be something like “crap and trade,” and I doubt anyone would go for that!
VeloBusDriver
Thank goodness I have cats. They only have a VW Golf’s impact. Wait, is that a VW Golf with a gas engine or the more efficient Diesel? 🙂
Clark Williams-Derry
Bigyaz -Doh! Thanks for the catch. That’s more than a bit embarrassing in a fact-checking post.Text now fixed, to reflect the correct country.
Sudha
What also needs to be considered is the influence that dogs have on their owners’ attitudes and beliefs. I grew up with a dog and while it’s fair to argue that my parents likely shaped my beliefs the most, having a dog meant that play time was often spent outside romping with him. I grew up with a love of the outdoors which was certainly heightened by my dog ownership. Now, having recently acquired a dog of my own (the first in my adult life), I find that this lovely addition to my life is similarly impacting my choices and decisions. I’m more likely to go for a hike or stroll in the park in my free time rather than staying indoors to catch up on the latest dance reality show. As a result, I’m more likely to vote for funding our city parks and protecting our trails (ok ok, I was likely to vote for that before – but I’m sure it changes for other folks). In general, having to care for him makes me more aware of the world and makes me more conscious in general. A plus for the environment? I think so.
Michweek
There is also more to this issue! I’ve always had mutt’s, either dogs and cats who strayed and found a home with my family, or animals we found at the shelters. I’d like to think as a green minded person, not only do I provide ‘green’ products for my dog, he’s also got a second chance. He’s fixed and will never produce more displaced and unwanted puppies. The best I could do with an SUV is run all to hell and then maybe part it out and try to get the steel recycled, but I don’t think my dog produces nearly as much methane, co2 and other green house gases as an SUV. So by purchasing my pooch I didn’t put more dogs out there I lowered the population, unfortunately purchasing even an used SUV probably just allows the previous owner to buy a new SUV.
Satan
Wow hippies, some people have a family and need an SUV to get around. Besides, most other countries don’t drive as far as we do annually so it could actually be feasible there… not that you’d know anything about somewhere other than your desk.
Matt the Engineer
[Satan] You have an odd concept of “need”. If you wanted, you could move to the city and walk your kids to their soccer games.
Maria Cahill
Part of this discussion really highlights well why sustainability concepts are not easily portable from one geographical region to another.
Pamela
An artful article and entertaining to boot. Interesting measurement challenges. OregonMichelle hits on the point I thought most missing from both the meme and Clark’s analyses (with a very punny idea). Here in the NW people like the BIG DOGS as much as some like the BIG CARS. To put it in perspective, think of an 80 pound human leaving waste in your yard all year. How would you feel about it? Trivial? How about 2? Here’s a way to get out of the drop-in-the-bucket mentality about it too – A nearby county working on fecal coliform problems in the watershed estimated that with 126,000 dogs + in their area, they had 20 tons of dog waste a day being dumped (!) on the ground. If it’s not mitigated, that’s like having a city of 40,000 people do the same thing (sorry for the unsettling imagery). So. Impacts. Yeah. But the food/fuel is just the start.
Steve Erickson
The sh**t from a city of 40,000 people is only equivalent to about 6 Atlantic Salmon feed lots in Puget Sound and the Washington Dept. of Ecology thinks that much crap going directly into the Sound is just fine!
Scoobie
Do people who have dogs buy big SUVs to cart them around?
charlie
I feed my dog vegetarian dog food. No grotesque “by-products”. She seems fine with it. What’s THAT do to the footprint?
Fausty
The entire “comparison” is even more facile and ill-supported than this excellent refutation can fully capture. Comparing the carbon footprint of dogs to SUVs is like comparing apples to a plastic orange. One is made of petrochemicals and, if burned for energy, will create carbon dioxide and other byproducts. The apple, in contrast, if eaten by a living being will not release all of its stored carbon into carbon dioxide (or any other nasty byproducts). Rather, most of the elements of the apple remain in the living ecological cycles of the planet.Those dogs, who eat the dogfood – the byproducts they create are some heat energy entropy (from the barking and running and wagging tails, etc.) and biological waste. I’d say an estimate of 90%+ of the solid and liquid waste stays directly in the environment. It breaks down into soil nutrients, is eaten by insects, becomes nutrients for grass and trees. Very little goes into waste treatment facilities, that’s clear. All of this “cycling by-product” from the dogs does NOT have the impact on global climate change that can at all be compared to a car burning petrochemicals (or plant-derived petrochemical substitutes). But, hey, how about we compare the “carbon footprint” of a herd of elk to a Boeing 747. After all, those nasty elk eat food – and that grass could theoretically be mutated into jet fuel to fly people around the world. So, the only conclusion is that we should massacre elk to “save the planet” from climate change. When we’re done with the elk, we can move on to the tress – after all, trees “use” all that water that could otherwise go to growing ethanol to make gas to run weedeaters…I’m sure these authors have laughed as they cart their winnings to the bank, having pawned off a specious load of tripe on some publisher – who then successfully misrepresented it as “science” and got gullible putative journalists to repeat their “facts” ad nauseum.The whole thing is a bit of a disgrace, isn’t it? The signal to noise ratio on these “news organizations” who spend so much time whining about how much they need corporate welfare to survive is dropping closer and closer to zero. Meanwhile, one well-educated blogger can rip apart a bullshit story like this in no time flat. Who are the “professionals” in need of societal subsidies, and who are the amateurs anyway?Fausty | cryptocloud.net
Different Take
I think a much more interesting comparison would be the impact of having a human child vs owning an SUV. I don’t think people take the long term impact to the earth into consideration in the decision whether to adopt or to procreate. Considering your child will probably eat meat, (and might drive an SUV and own a dog too) I think this is the single most influential decision people will make in their lives with respect to the long term future of people living on this planet.Also I think this also brings up the tradeoff of quality of life vs environmental concerns. Of course there are many things you can do to reduce your impact on the earth, but some people are willing to give up a lot of quality of life and some are not.
misha
It’s very well-established that livestock (cows and pigs) are by far the #1 cause of global warming emissions. Why does Sightline and the political establishment ignore this? What would reduce emissions more – a comprehensive cap-and-trade system on carbon dioxide or a simple 10 cent tax on beef and pork products? Why is this such an untouchable issue for even progressives?http://www.fao.org/newsroom/en/news/2006/1000448/index.html
Jessie
Nowhere do any of the authors consider the fact that my dogs eat left over pizza for breakfast thus reducing everyone’s carbon footprint if not waistline.
niall
Misha makes a good point: what about GHGs from dog burps? Scoobie makes another one: are dog owners more likely to own SUVs than folks who own cats or jerbils? Probably! Maria makes a third: are research results from other countries invalid because they down conform to our obscene levels of consumption in the U.S.?
Real American
It is sad that even the author of an otherwise fairly rational article still feels guilty enough about the environmental impact that he cannot justify owning a dog. If he is that worried about the planet, he should not have kids. Don’t let the radical enviro-nazis dictate your life! Live sensibly and don’t worry about them.
Real Cascadian
It is sad that the commenter above still feels threatened enough by those who try to inform people of the social consequences of their choices that he cannot countenance people worrying about the planet. If you are that frightened of information, you should not read positive media. Don’t let Fox news dictate your life! Live informed and don’t blindly make others pay for your choices.
Matt the Engineer
Maybe dogs do have a larger impact than I imagined. A friend of mine is looking for a home to buy so that he can move out of his east side condo. He started talking about a house in far-off exurbs, and I started immediately trying to talk him into a house or condo in the city. “I can’t live in the city” he told me “I want to get a dog.”Adding the long commute – possibly in an SUV (for towing his dog around), the larger house, the extra infrastructure for exurban living… this dog will end up using more energy than his owner.
Walt Hutchens
Clearly implied in some of these excellent posts is that dog wastes are fertilizer. In many places they can replace fertilizer that would otherwise be purchased. (Some health precautions must be taken.) Properly fertilized land grows everything more vigorously, thus more rapidly sequestering carbon—that is, helping to clean up behind the SUV or even the Prius and the school bus.In densely populated areas the wastes would have to go through the sewage system and I don’t know what fraction is now recycled or at what energy cost. In other places an acre of land would easily absorb the wastes from several medium size dogs. This requires modest daily work: Would it be better for the planet that we not do that work and instead drive the SUV to our health club for exercise?If you follow the whole chain, the unavoidable byproducts of human consumption of meat and other animal materials are combined by our dogs with water and processed into fertilizer that can promote growth of vegetable materials of all kinds, from human food (with suitable but easy precautions) to food animal feeds (recycling!), to fuel and fiber (trees), to beauty (lawns, flower gardens), to trapping of carbon. It is breathtakingly stupid to call this a problem caused by dog ownership.
alice in LLALA Land
Cannibalism.. It what’s for dinner….
Mary
This stuff is getting so out of hand, it’s ridiculous! How long will it be until our efforts to save the planet make our lives not worth living? Give up my dogs? NEVER! Give up my SUV? NEVER! It’s the only thing that I can get my grandkids and dogs into at the same time. Dogs give us so much more that cannot be measured, from bomb-sniffing, to a child’s confidant, there are a myriad of jobs they do. How long will it be before they start mandating human sterilization to control the population? Let’s eliminate all animal life and leave the planet to the plants… Such nonsense…
Matt the Engineer
“How long will it be before they start mandating human sterilization to control the population?”Not long… specifically 30 years ago. The world would have a quarter billion more people if this policy didn’t exist.
Linda over the hill
Wow, is THIS a bizarre discussion or what! Keep in mind, most animals, including some kind of dog, were here first. Most environmental problems seem to have originated from the increased number of humans. ZPG!
Janna B
Geeze we will eventually get down to do vegans produce more or less than meat eaters and if it comes down to vegans then guess they will be the hated group for the century. Good Lord this is another “movement” excuse the pun to remove animal ownership and farming and eating meat and don’t forget the horses and those horse stables…..then, then just what will be next that needs to be removed from the earth in order to “save it”. I would like to hang on with what I have and when my time is up, it is up. The vegan animal rightist pleading for voice for animals….(they don’t talk folks)…and the greenies who are saving the world from itself,,,,,,,,and then there are rational people who do not run on emotion, and appreciate science (but seems even that can be fudged to prove a point), lets call them, the sane people.
karen
There is an issue about dogs that really hasn’t been addressed in this article. Dog Waste, pet waste in general. I recently did research and an interview about pet waste, here where I live and it is staggering. In our county alone it is estitmated we have over 177,000 dogs that squat outside somewhere on a daily routine. NO this cannot be used as fertilizer as their is too much bacteria in it. If the waste can be heated to a hot enough temperature, but that is not happening in our yards, or composting systems here in the NW.Our issue with pet waste is water quality, killing our seas and all that live in it, which help to create the circle of life.
Ted
Dogs and cats were not created by nature to be used by humans as companions. Animals like these were wild animal that were used by humans for specific reasons and then became domesticated. Dogs were used for hunting/scavenging, cats to rid vermin. These animals were fed the leftovers or had to scavenge to survive. Now we have big industries just for feeding these animals. I’m sure these New Zealand researchers are correct with their statement.
Clark Williams-Derry
Ted -I disagree only with your last statement. Dogs and cats do have an environmental impact. But the climate impact attributable to a pet dog is much lower than that of an SUV.
moonjets
You’ve fully persuaded me that SUVs are worse for the environment than dogs. One thing, though: you seem to assume that the USA is self-sufficient in food production. It isn’t: it’s been a net importer of food since 2005.<blockquote>But now U.S. imports of meat and grains—to name two commodities that used to be our strength—are rising. America now imports two dollars of feed grains for every three dollars of exports, and imports $2.5 billion more red meats than it exports, ERS data show.</blockquote>
Lev
I think I’m still with the SUV. An average SUV might travel 13,700 miles per year in the U.S. but distances are longer there. An SUV in Europe is more likely to be used on a day to day basis due to its practicality with the average 2.3 kids. Most SUVs don’t even leave the country in Europe where as a crossing a couple of state lines is no big deal in the U.S.
Steve Erickson
If my Husky didn’t insist on walking / running me damn near every day while she scavenges sea gull carcasses I would be consuming a lot of high tech medical care. I don’t know what the Carbon footprint of that would be, but its probably not trivial.
Anyway, this discussion pretty clearly shows that you can take the hominid out of the Pleistocene, but you can’t take the Pleistocene out of the hominid. We must have our companion wolves around.