It’s about even in terms of the environmental impact of cats and dogs

The big question today should be which companion animal, between cats and dogs, is more environmentally friendly? After all, environmental issues are gradually rising to the top of the priority list. And it seems to me that there are two major factors which help us gauge which animal is more environmentally friendly. These are the foods that they eat i.e. what goes into them, and how we deal with what comes out of them in terms of waste, which for the cat often means using cat litter.

In terms of environmental impact it is pretty even between cats and dogs
In terms of environmental impact it is pretty even between cats and dogs. Image: Pixabay.
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Resources required to feed a dog or cat

You may have heard about it, a book called Time to Eat the Dog? The Real Guide to Sustainable Living by authors Brenda and Robert Vale. They could have picked a better title as the one they selected might encourage eating dog meat which is objectionable to put it mildly.

In feeding a cat and dog you have to work out how much land is needed to produce the food. This by the way is a reason why the planet can only sustain a certain limited human population but that is another story. In their calculation, they worked out that dogs have about twice the eco-footprint as the building and fueling of a Toyota land cruiser (a large vehicle), whereas the vehicle equivalent of a cat would be a Volkswagen Golf.

It must have been a complicated calculation but they analysed the ingredients of common brands of pet food. They assessed a medium-sized dog as consuming about 90 g of meat and 156 g of cereals daily in a recommended portion of dry dog food of 300 g. They figured that in one year a dog eats about 164 kg of meat and 95 kg of cereals. It takes 43.3 m² of land to generate 1 kg of chicken annually and 13.4 m² to generate a kilogram of cereals. This gives a footprint of 0.84 hectares for a medium-sized dog.

They worked out that an SUV eco-footprint is about 0.41 ha. They used a Toyota land cruiser driven about 10,000 km annually as a standard which uses 55.1 GJ. 1 ha of land can produce 135 GJ a year which they calculated as being an eco-footprint of 0.41 ha which is less than half of the dog’s.

The cat has an eco-footprint of 0.15 ha which is slightly less than a Volkswagen Golf using the same methodology.

So, on the environmental impact of feeding cats and dogs, the cat wins by a substantial margin.

Cat litter – domestic cats

The main users of cat litter are full-time indoor cats, in developed countries. I’m sure that in many countries cats do not use cat litter but go to the garden to do their toilet. But cat litter is very big business globally at USD 9.75 billion in 2020.

The most common and most popular cat litter is clumping cat litter made from clay which is mined in vast quantities. The product that is mined is called Fullers Earth and it is excavated from the Earth’s surface in the millions of tons leaving pits which are unsightly and a scar on the landscape. Mining damages the environment of many wild animals through deforestation, erosion, loss of wildlife habitat and a depletion of natural minerals. Sediments can get into streams and rivers which pollutes water. And strip mining is dusty, noisy and ugly.

The clay has to be processed requiring more energy. It is baked at high temperatures, up to 2000°F, to remove any moisture. This makes the clay absorbent. It is cooled and crushed into fine granules and then packaged and shipped to the customer.

After its use, it has to be returned to landfill with the accompanying faeces and urine. Clay litter is not biodegradable. It goes into the trash and then to landfill. It is trapped in plastic for how many thousand years, I don’t know. Defecating directly into toilets avoids cat litter but damages sea-life as toxoplasmosis gets washed into the oceans apparently.

We know that dogs don’t use cat litter! For dogs, the modern trend in developed countries is to pick up the faeces in a plastic bag and dispose of the bag in a specially constructed, publicly available and accessible dog poop receptacle! There is no litter involved and therefore no scarring of the landscape but there is of course the disposal of the faeces in small plastic bags in the general waste where it must end up in landfill.

Environmentally Friendly Cat Litter



The study about the environmental impact of creating food for cats and dogs does not, as I understand it, take into account the full environmental impact of these companion animals which is why I think you have to factor in what we do with the stuff that comes out of them. The environmental impact might not be as big but this aspect of companion animal ownership must be factored in when trying to work out which animal is more environmentally friendly.

It seems to me that the lesser environmental impact of feeding domestic cats is counteracted by the higher environmental impact of disposing of waste products because of the need for cat litter. That is why, in the title, I have deduced that it is a fairly evenly balanced result. Wrong? Please tell me in a comment.


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