FAQs

Dogs and cats are part of the family, but they also rely on food, products and services that use land, water and energy. When this is added up across hundreds of millions of animals, the impact is surprisingly large.

Research suggests that feeding pets accounts for a substantial share of the impacts of global livestock production and national greenhouse gas (GHG) emissions. Pet food ingredients alone may account for 1% or more of total national emissions in some high income countries [1][2][3][4].

Looking at these impacts is not about blaming people for having pets. It is about understanding where the biggest effects come from so owners, vets and policymakers can make informed, realistic changes.

For most pets, food is likely the biggest part of their environmental impact [5].

In human food systems around 80–90% of the climate impact of food comes from producing ingredients on farms, not from manufacturing, packaging, transport or retail [6]. Life cycle assessments of dry kibble type pet foods also suggest most impacts come from the ingredients [7][8]. For wet foods, the other impacts associated with food – including manufacturing, packaging, transport, retail, storage and waste - are also very important [7][9].

Other aspects of pet care do also matter and are covered in other FAQs. But diet is a very large, and potentially changeable factor, so an important place to start.

The footprint of a pet depends heavily on its size and what it eats.

• Feeding a medium sized dog some high meat diets can create similar or higher GHG emissions than an average human diet, and even approach or exceed those of a high meat human diet.

• Globally, the emissions from producing food to feed all pet dogs have been estimated at hundreds of millions of tonnes of CO₂ equivalent per year, similar in scale to a large fraction of commercial aviation emissions. [1]

Pet food contributes to several types of environmental pressure, very similar to those from human food [6][10]:

• Climate change (greenhouse gas emissions): Mainly from raising livestock (particularly cattle and sheep), producing animal feed, and using fertilisers and energy.

• Land use and biodiversity loss: Land used for grazing or growing feed crops can replace forests, grasslands and wetlands, affecting wildlife habitats.

• Water use and water scarcity: Irrigation for crops, and water used in animal farming and aquaculture, can put pressure on freshwater resources.

• Nutrient and air pollution: Nitrogen and phosphorus run off into rivers and lakes (eutrophication), and air pollutants like ammonia and nitrogen oxides (acidification), come largely from manure and fertilisers.

The size of these impacts varies hugely between different pet foods, and is strongly linked to the type and amount of animal based ingredients used.

A lot of pet food does use animal by products—things like offal, meat trimmings and rendered fats that are less commonly eaten by people [1][11]. This can be a good way of using more of each animal.

However, this does not make pet food “impact free”:

• If there were no demand for pet food, fewer animals might be raised overall, and fewer by products would be produced. 

• The way environmental impacts are shared out between prime cuts and by products (called “allocation”) makes a big difference to estimates, but in most accepted methods by products still carry some share of the total footprint [12][13].

In general:

• Diets that rely heavily on prime meat cuts (especially beef and lamb) have the highest impacts. 

• Diets that use more by products, together with plant ingredients, tend to be lower impact—but not zero impact.[1][2]

When an animal is slaughtered, it produces many products, not just “meat”: prime cuts, mince, organs, fats, bones, etc. Allocation is the rule used in life cycle assessment (LCA) to decide how to share the farm’s environmental impacts across all these different outputs. Different allocation choices can lead to very different results for animal by products, which is one reason pet food footprint estimates can vary a lot [1][6][12][13]. 

Common approaches include:

• Economic allocation (shared by market value). The most valuable outputs (often prime cuts) get a larger share of impacts; lower value by products get a smaller share. This approach is widely used in meat LCAs and is recommended in several LCA contexts where co products differ greatly in value. 

• Mass allocation (shared by weight). Impacts are split by kilograms of output. This usually assigns more impact to heavy, low value by products than economic allocation does. 

• Nutrient/energy allocation (shared by protein or calories). Impacts are split based on nutritional content (e.g., protein).

• “No allocation” (a shortcut that can overestimate). Sometimes a study takes an impact factor calculated for prime meat / retail meat and applies it to all carcass products, including by products. This is a problem because the prime meat impact factor is typically calculated as if that meat carries most of the animal’s burden (often using economic allocation). Applying the same “prime meat” factor again to organs, fats and other co products can double count the same farm impacts, making the total footprint look much larger than the real footprint of producing the whole animal. 

Good footprint estimates are transparent about allocation choices and ideally show results under more than one method (e.g., economic and mass) so readers can see how sensitive results are to this assumption.

Yes. The differences between protein sources are large and fairly consistent across studies [6]: 

• Beef and lamb: Among the highest greenhouse gas emissions and land use per unit of protein. Pet foods rich in beef typically sit at the top of the impact range. 

• Chicken and pork: Lower impact than beef and lamb, but still substantially higher than most plant based proteins when considering prime cuts of meat. Meat by products of these types have lower impacts and are relatively sustainable options.

• Fish and other aquatic foods: Greenhouse gas emissions can be moderate, but there can be high impacts on water quality and marine ecosystems, and concerns about overfishing [10][14]. 

• Insects: Studies do suggest that insect meals (for example from mealworms) can have lower land use and GHG emissions than conventional prime cuts of meat, though they are not impact free. However, the impact of insects varies widely depending on what they are fed on and some assumptions on their environmental credentials are now being challenged. Insect meals may well not be lower impact than meat by products [15][16]. 

• Plant based proteins (e.g. soy, peas, grains): Typically, the lowest greenhouse gas emissions and land use per unit of protein when fed to humans, although impacts vary with crop type and where/how it is grown [6]. Comparisons with meat by products are less clear-cut.

Yes. Dogs are flexible eaters and can do well on a variety of diets as long as these are nutritionally complete and balanced. Lower impact options for dogs include:

• Conventional complete dry foods that are not excessively high in meat and that rely more on poultry and by products rather than large amounts of beef or lamb. 

• Carefully formulated diets that include more plant protein or are entirely based on plant proteins, provided they meet recognised nutrient guidelines (for example those of FEDIAF) [17][18]. 

The single biggest shift, from an environmental perspective, is typically moving away from very high prime meat (often wet or raw diets) towards diets with moderate meat content and fewer high impact meats (based on meat byproducts, not prime cuts)

Any significant diet change should be done gradually. Please ensure you discuss with a vet if you have any concerns, particularly for dogs with medical conditions.

Cats are typically viewed as obligate carnivores, meaning they have specific nutritional requirements (for example for taurine, arachidonic acid and vitamin A) that are naturally supplied by animal tissues [17]. 

Commercial plant based cat foods do exist, and some owners report healthy cats on these diets, but solid, long term, independent clinical research is still very limited. The British Veterinary Association Policy Position, which reviewed research evidence, advises: “Current research suggests that it is not possible to form a complete vegan or vegetarian diet for cats” [18].

Changing cats’ diets by reducing higher impact meat products, avoiding overfeeding, and using foods made with meat by-products can significantly lower environmental impacts.

Any significant diet change should be done gradually. Please ensure you discuss with a vet if you have any concerns, particularly for cats with medical conditions.

Evidence from several studies points to a few practical starting points [1][2][3][9]: 

1. Choose lower impact formats where suitable 

   • Feeding a complete dry food usually has a lower impact than feeding mainly wet or raw food, especially when the wet or raw diets are very meat rich or beef based.

2. Avoid unnecessary “high meat” formulations

   • Diets marketed as “grain free”, “high meat” or “human grade” may contain more prime meat, which increases environmental impact without clear health advantages for most pets. 

3. Manage portion sizes and body weight 

   • Overweight pets need more food over their lifetime, which increases both health risks and environmental impacts. Following feeding guidelines and monitoring body condition can reduce this. 

4. Consider alternative proteins 

   • Try formulations that use more poultry, meat by products, plant proteins and less beef and lamb. 

5. Reduce waste 

   • Store food correctly, use pack sizes you can finish, and try not to routinely discard uneaten portions.

Always check with your vet before major diet changes, especially if your animal has specific health needs.

Food is likely the biggest factor, but there are several others:

• Excreta (faeces and urine): Dogs and cats collectively produce large amounts of nitrogen and phosphorus in their waste, along with associated GHG emissions [19]. 

• Impacts on wildlife: Free roaming cats, and to a lesser extent dogs, prey on wildlife and can disturb sensitive habitats just by their presence [20].

• Litter, poo bags and plastic waste: Litter production and disposal, single use poo bags, toys and packaging create material and waste impacts. 

• Travel and services: Driving to dog walking locations, vet visits, grooming, boarding and pet related tourism all contribute to emissions. 

• Land and soil impacts: Dog fouling in public spaces can affect soil nutrient levels and water quality, particularly when not collected.

• Medicines: There are significant environmental impacts from medicines used on pets entering the environment, especially parasiticides (which are used to treat and prevent parasites including fleas, ticks and worms) [21].

There is no perfect solution, but some choices are better than others.

• As well as being a nuisance and a public health risk, dog faeces left on the ground add nutrients and pathogens to soils and waterways and also contribute to GHG emissions [24].

• Best practice in most areas is to:

  • Pick up after your dog using a bag. 

  • Dispose of the bag in general waste (or a dedicated dog waste bin) according to local guidance.

Bags labelled “biodegradable” or “compostable” only provide benefits if they end up in facilities where they can actually break down. In typical landfills they often behave similarly to ordinary plastics.

Because pet waste contains nutrients and pathogens, the priority is to collect it and dispose of it safely, rather than leave it in the environment.

It is reasonable to include environmental impact as one factor among many when deciding:

• Whether to have a pet at all. 

• What species to keep (for example, a large dog vs. a small dog vs. a cat). 

• How many animals to keep in the same household.

In broad terms:

• Larger animals generally eat more, and therefore have a higher lifetime food footprint, than smaller ones. 

• Multiple pets multiply that footprint, especially when they are fed high meat diets.