If you’re considering adding a four-footed companion to your family, you might be wondering about your future buddy’s potential environmental impact — specifically if cats are easier on the earth than their canine sidekicks. As a cat owner, I have wondered this myself! The answer depends largely on the size of the animal and how much they eat. Large dogs such as German Shepherds require substantially more food than smaller breeds like Chihuahuas.
Large dogs are always worse for the environment than smaller dogs or cats when it comes to food-production-associated environmental burdens. But when you factor in the environmental costs related to the production and disposal of kitty litter, dogs who weigh less than 10 pounds or so may be better for the environment than similarly sized cats. Come with me as I walk you through the details:
Why Does the Amount Dogs and Cats Eat Matter?
A great deal of the damage we do to the earth is directly related to the production and consumption of food, meat in particular. The more meat a cat or dog eats, the greater their carbon footprint, making an animal’s size important when it comes to determining their environmental impact.
But let’s start at the beginning—with vegetable and cereal farming. All farming has an environmental impact, even when we grow fruits and vegetables using organic principles. (Organic farming often requires tons of land.)
Due to modern farming’s high production demands and consumers’ aesthetic preferences, producers often turn to pesticides and fertilizers to protect and improve harvests. Many of these chemicals cause serious environmental damage as they accumulate in the soil and contaminate water sources.
Then there are the greenhouse emissions related to the physical activities involved in farming—think running machinery and transporting products. And don’t forget to factor in everything involved in producing and delivering even the most basic packaging.
Meat production is a spectacularly inefficient way to produce food as this process essentially gets repeated twice before you can buy a bag of kibble. Studies indicate that pound for pound, farming just 1 pound of beef releases the same amount of carbon dioxide into the atmosphere as producing 15 pounds of rice or 60 pounds of corn, peas or wheat.
Put another way, producing 1 kilogram of chicken requires approximately 43.3 square meters of land. (Beef and lamb require far more than that!) A whole kilogram of grain, on the other hand, only demands a mere 13.4 square meters of land.
Meat production is problematic for other reasons as well, including the methane gas produced by ruminants like cows. The rumen is a special stomach compartment present in many grazing mammals. It’s where food that hasn’t been completely digested is stored and begins to ferment before being sent to the other parts of the stomach to be broken down and absorbed. Methane gas is produced during this fermentation process. But methane soaks up atmospheric heat like there’s no tomorrow. According to the MIT Climate Portal, methane gas “traps around 100 times as much heat as carbon dioxide.
What Does This Mean in Real Terms?
In 2009, Barbara and Robert Vale, professors who study sustainable building and teach at Victoria University of Wellington, published a book in which they crunch the numbers regarding the negative environmental impact of pet ownership — Time to Eat the Dog: The Real Guide to Sustainable Living. Their conclusions were shocking.
The average medium-sized dog apparently eats about 164 kilograms of meat and 95 kilograms of grain per year. After factoring in the amount of land needed to produce chicken and various grains, the Vales calculated it requires approximately .84 hectares of land to feed a dog the size of a Labrador Receiver. You only need around .41 hectares of land to produce enough energy to drive a Toyota Land Cruiser 10,000 miles.
Cats are smaller and require far less food than the average dog, but they’re not exactly environmentally friendly! Feeding just one cat requires .15 hectares of land, just a bit less than you’d need to keep a Volkswagen Golf up and running for a year.
A more recent study published in PLOS One reached similar conclusions while describing the phenomena a bit differently. After tapping the American Kennel Association for information about the 10 most popular dog breeds, Gregory Orkin, author of this innovative 2019 study, averaged their weights. According to Orkin’s calculations, the average dog in the United States weighs 22 pounds, more than the average cat who tips the scales at 10 pounds. Dogs require 544 kJ (kg BW)-0.75 d-1 of energy to survive. The corresponding number for cats is 544 kJ (kg BW)-0.67 d-1.
Due to weight differences, the environmental impact of feeding the average pet cat is lower than that involved in keeping an average dog properly fed. When weight and population numbers are factored together, US dogs consume far more than US cats.
Companion animal ownership has serious environmental consequences—cats and dogs together eat around 24% of all the animal-based energy consumed in the US or about one-third of the meat eaten in the country. These numbers might seem exaggerated until you realize that around 70% of US households have at least one pet—there’re around 69 million homes with pet dogs and 45.3 million homes with cats.
The United States has the largest companion animal population in the world. And we could feed around 62 million people with the food and energy that goes into food production for US pets.
And things will probably get worse as worldwide trends in pet ownership continue. While companion pets have been common in North America, Europe, and Australia for decades, the practice is becoming increasingly common in developing and middle-income nations. As the number of companion animals kept in homes around the world increases, so too will the magnitude of these animals’ environmental impact.
There also appears to be a shift in values underway, altering the way many think of cats and dogs. According to Orkin, the humanization of companion animals may actually spur more environmental destruction as pet owners begin demanding higher-quality cuts of meat for their cats and dogs.
What About Poop and Kitty Litter?
Our animal companions aren’t doing us any favors in the poop department, either. The average human poops out about 0.147 kg capita-1 d-1. That number is around 0.042 kg cat-1 d-1 for cats and 0.15± 0.07 kg dog-1 d-1 for dogs. Cats tend to weigh much less than dogs and therefore produce less waste on average.
Dogs and cats together are responsible for about 23% of all poop excreted in the US—humans are responsible for the rest. Companion dogs and cats produce as much waste as the human inhabitants of a state around the size of Massachusetts, most of which ends up in landfills where it decomposes, releasing methane — a major contributor to global warming—into the atmosphere.
And then you have the environmental impact of all that kitty litter. Unfortunately, most studies evaluating the environmental impact of pet ownership only consider the consequences of feeding companion animals, failing to account for factors such as the costs of producing and disposing of kitty litter, which are quite substantial when you consider the harms caused by strip mining for clay, the resources expended in the packaging and transporting of litter related products and the contribution non-biodegradable litter makes to our growing landfills.
Clay and silica/crystal-based litters are simply not biodegradable, putting most cat owners in the unpleasant position of adding to landfill waste and contributing to global warming each and every time they change their cat’s litter.
There are a few ways to get started if you’re serious about reducing your cat’s environmental impact. One is super simple—the others require a bit more commitment and planning. The quickest and easiest way to reduce your cat’s environmental impact is to use biodegradable bags to dispose of waste when you clean or change the litter. You can easily find small biodegradable poop-disposal baggies at most grocery stores. And there are tons of biodegradable trash bags and cat pan liners to choose from.
Switching to biodegradable litter is a more involved option, but it can be a great choice if you have the interest, the money and your cat tolerates the change. There are tons of biodegradable options on the market made from sustainable products such as recycled newspapers, dried tofu and wood chips. There are clumping and non-clumping varieties as well as fragranced and unscented choices. You can even compost un-peed or pooped on parts of used litter to seriously limit any cat-related landfill contributions. Just remember to only sprinkle compost with cat litter on nonedible plants.
If you’re really serious about minimizing your cat’s environmental footprint, consider purchasing pet food from a company that explicitly factors the protection of the earth into its business model. There are several pet food makers, such as Open Farm, that adhere to strong sustainability and transparency standards and others, such as The Honest Kitchen, that operate as B corporations pledged to factor elements such as sustainability and justice into their business models.
And carbon offsets are a thoughtful and super practical way to give just a bit to the world and to thank the earth (and your fellow human beings) for the privilege of welcoming a furry companion into your life. (Here’s a link to an article with a few tips on how to find a reputable carbon offset program that aligns with your values).