The US Environmental Protection Agency estimated that just 100 days' worth of droppings from two or three dogs would create enough bacteria to make a bay and its 40km surrounds off-limits and unsafe for swimming and shellfishing.
Here in Australia, pet waste comprises a significant 3.8 per cent of the country's total landfill, mostly because the waste is placed in nondegradable plastic bags and so will never break down.
There are some fairly easy steps pet owners can take to reduce the carbon pawprint:
1. Clean up after your pet. Don't let the waste be flushed down drains and waterways.
2. Use biodegradeable bags to dispose of waste. It will eventually go back to nature.
3. Recycle your pet's waste. Composting waste is great for the garden. You can also buy in-ground, pet septic loo systems that work brilliantly for keeping the carbon print minimal.
4. Use eco-friendly cat litter and biodegradeable pan liners. Clay litters are not good for the environment because the clay is strip-mined and doesn't break down. Natural alternatives are made from wheat, corn or recycled newspaper.
5. Feed your pet a diet that is as natural as possible. Try to feed your cat and dog food that has been grown and processed locally because this represents significant savings on fuel and transportation. Avoid foods containing hormones and additives and
try to buy organic, minimally processed products where the animals used have been humanely raised and treated. Dry food tends to be a more eco-friendly option than canned food because it uses less packaging.
6. Brush your pet regularly to reduce the load on the vacuum cleaner. Also try to use eco-friendly grooming products. Avoid products that contain sulphates, phosphates and other chemicals that leave a 'toxic trail'.7. Buy your pet eco-friendly non-toxic toys. You can buy a range of natural toys and accessories for pets, including hemp collars and leads, cardboard scratching posts and bedding or, better still, make your own. The new book Eco Dog by Corbett Marshall and Jim Deskevich (Chronicle Books, $24.95) is full of ideas for 'green' approaches to raising pets - including how to make a dog bed out of old jeans.