Are our pets costing us the earth?

Air travel, meat production, fast fashion, plastics and the consumption of fossil fuels all have serious, well-documented environmental impacts. There is now a real focus on making our homes and lives as ‘green’ as possible. But what about the smaller creatures that share our homes? Have we considered the environmental impact of our pets?

In the United States alone, there are between 150-200 million dogs and cats1. The production of food for these primarily meat-eating animals makes up 30% of the environmental impact of animal agriculture2, which roughly equates to the same dietary energy as 62 million Americans. This, combined with waste disposal, accounts for 64 million tonnes of the dangerous greenhouses gases nitrous oxide and methane3 - which is the same emission levels as 13.6 million cars4.

Feeding our pets

Angela Bartram is an Associate Professor and Head of Arts Research at the University of Derby, and animals in social contexts is one of her main areas of research: “While feeding our animals is clearly less environmentally invasive than feeding humans, it would be beneficial to be mindful of what you are serving up, particularly as they aren’t demanding in their connoisseurial tastes, they just have what you give them.

“Historically, in working-class households, dogs have eaten exactly the same things humans have. Since the 1980s, there has been a drive for pets to have a vegetarian and vegan lifestyle, which would help to lessen their environmental impact but, while this is perfectly fine for dogs, it doesn’t work as well for cats.”

That is because cats are “hyper carnivores”, explains Maren Huck, Lecturer in Animal Behavioural Ecology at the University of Derby, “and they cannot survive without meat. The best thing to do to reduce the environmental impact of feeding your cat is to give them ethically sourced food.” However, the pet food industry claims that far from being unsustainable, pet food actually uses material that is surplus to requirement from the human food industry – without pet food, all that waste would go to landfill5.

Local ecology

But it is not just their diet that we should be conscious of, pets can also have a significant impact on our local ecology. Peter Marra, Professor and Director of the Georgetown Environmental Initiative, says: “Cats and dogs, largely feral but also owned, have contributed to a number of species extinctions globally and continue to threaten and endanger hundreds more. In the UK, pet cats are estimated to kill upwards of 275 million prey items annually, and most of these are native species6.”

Maren recognises the negative effect cats can have on local wildlife, but claims: “There can also be beneficial effects, such as keeping the numbers of mesopredators, like rodents, down so that they don’t affect other species.

“However, if your cat is a proficient hunter, a collar with a bell could be considered.” Angela notes that some pets can actually be so well established that they are now a vital part of the local ecosystem: “Horses are often kept in woods or fields where they have become an integral part of the lifecycle. They graze an area and then move on to different fields, leaving the area to regain its vitality. Their grazing also contributes to keeping the woodland manageable.”

Grey cat sat next to a bush


Pet waste is also an environmental issue, with US pets producing about 5.1 million tonnes of faeces every year. London’s Richmond Park sees around 100 tonnes of dog faeces left annually, and even the urine of our pets can cause damage to local park areas7, coastal zones and waterways. However, this is a complex issue, as even the recommended way of disposing of pet waste can have damaging impact. Angela explains: “Picking up waste in plastic bags and leaving it in woodlands is a big no-no. It should be moved off footpaths into grass or bush areas and left in the ground to rot. Poo bags often use nonbiodegradable plastic which is ridiculous. This aspect of pet ownership is hugely problematic.”

Illegal trade

However, cats and dogs should not shoulder all of the blame. Some fish and exotic animals need warmth and light to survive and the light bulbs and tanks required can use a huge amount of electricity, which, in turn, produce a significant amount of CO28. The demand for these types of animals has also fuelled the illegal pet trade. In his article ‘The Ecological Cost of Pets’, Peter Marra discusses how many of these exotic animals are taken from the wild, which impacts local populations. It also risks an invasion of these creatures and the pathogens they carry into a novel ecosystem. Maren says: “When purchasing, owners need to take the welfare and environment of the species into consideration. Never buy wild-caught animals and only buy from certified breeders.”

Responsible ownership

So, with the huge variety of environmental impacts, should we just give up our pets altogether? Peter says: “No, but we do need to educate and regulate pet ownership more carefully. There are tremendous mental and physical health benefits to owning a pet, and we should encourage responsible pet ownership9.”

Angela adds: “The sense of wellbeing that comes with owning a pet is really important. We have domestic pets because we need to be close to a familial other. Contact, including non-verbal contact, between beings is important for fostering a sense of belonging and grounding.

“Animals are closer to nature because they are extremely empathetic and have no ego. Humans are the most destructive animals on the planet, so we can learn a lot through our pets’ behaviours. They help us be more empathetic to things outside our immediate sphere, get closer to nature, and have a less impactful relationship with it.”

  1. Marra, Peter (2019). The ecological cost of pets. Current Biology Magazine
  3. Marra, Peter (2019). The ecological cost of pets. Current Biology Magazine
  6. Marra, Peter (2019). The ecological cost of pets. Current Biology Magazine
  9. Marra, Peter (2019). The ecological cost of pets. Current Biology Magazine