Pet dogs have ‘extensive and multifarious' impact on environment, new research finds

The Guardian

09-04-2025

Dogs have 'extensive and multifarious' environmental impacts, disturbing wildlife, polluting waterways and contributing to carbon emissions, new research has found.
An Australian review of existing studies has argued that 'the environmental impact of owned dogs is far greater, more insidious, and more concerning than is generally recognised'.
While the environmental impact of cats is well known, the comparative effect of pet dogs has been poorly acknowledged, the researchers said.
The review, published in the journal Pacific Conservation Biology, highlighted the impacts of the world's 'commonest large carnivore' in killing and disturbing native wildlife, particularly shore birds.
In Australia, attacks by unrestrained dogs on little penguins in Tasmania may contribute to colony collapse, modelling suggests, while a study of animals taken to the Australia Zoo wildlife hospital found that mortality was highest after dog attacks, which was the second most common reason for admission after car strikes.
In the US, studies have found that deer, foxes and bobcats were less active in or avoid wilderness areas where dogs were allowed, while other research shows that insecticides from flea and tick medications kill aquatic invertebrates when they wash off into waterways. Dog faeces can also leave scent traces and affect soil chemistry and plant growth.
The carbon footprint of pets is also significant. A 2020 study found the dry pet food industry had an environmental footprint of around twice the land area of the UK, with greenhouse gas emissions – 56 to 151 Mt CO2 – equivalent to the 60th highest-emitting country.
The review's lead author, Prof Bill Bateman of Curtin University, said the research did not intend to be 'censorious' but aimed to raise awareness of the environmental impacts of man's best friend, with whom humans' domestic relationship dates back several millennia.
'To a certain extent we give a free pass to dogs because they are so important to us … not just as working dogs but also as companions,' he said, pointing to the 'huge benefits' dogs had on their owners' mental and physical health. He also noted that dogs played vital roles in conservation work, such as in wildlife detection.
'Although we've pointed out these issues with dogs in natural environments … there is that other balancing side, which is that people will probably go out and really enjoy the environment around them – and perhaps feel more protective about it – because they're out there walking their dog in it.'
Angelika von Sanden, a trauma therapist and the author of Sit Stay Grow: How Dogs Can Help You Worry Less and Walk into a Better Future, said she had observed that for many clients the companionship of a dog was often 'literally the only reason to survive, to get up, to still keep going'.
'It gives them a reason to get up, a reason to get out, a reason to move around and be in contact a little bit with the world outside,' she said.
'Dog owners can get a bad name if they are not aware of the surroundings they are in and of other people around them,' she noted.
In the review, the researchers attributed the extent of the environmental impacts to the sheer number of dogs globally, as well as 'the lax or uninformed behaviour of dog owners'.
A simple way to mitigate against the worst impacts was to keep dogs leashed in areas where restrictions apply and to maintain a buffer distance from nesting or roosting shorebirds, the paper suggested.
'A lot of what we're talking about can be ameliorated by owners' behaviour,' Bateman said, pointing out that low compliance with leash laws was a problem.
'Maybe, in some parts of the world, we actually need to consider some slightly more robust laws,' Bateman said, suggesting that dog exclusion zones may be more suitable in some areas.
Bateman also raised sustainable dog food as an option to reduce a pet's environmental paw print, noting however that 'more sustainable dog food tends to cost more than the cheap dog food that we buy which has a higher carbon footprint'.
'If nothing else, pick up your own dog shit,' he said.