Is It Really Time To Eat The Dog?

Scientists calculate eco-pawprints of our household pets

Picture the scene - an driver opens the boot of their Toyota Land Cruiser to let their dog out for a walk in Chiswick House. But should they be considered an eco-outcast for their choice of vehicle or their choice of pet?

It's the latter according to sustainable living experts Robert and Brenda Vale who, in their new book Time to Eat the Dog: The real guide to sustainable living, compare the ecological footprints of popular pets with those of various other lifestyle choices including owning an SUV.

To measure the ecological paw, claw and fin-prints of the family pet, the architect couple analysed the ingredients of common brands of pet food. They calculated, for example, that a medium-sized dog would consume 90 grams of meat and 156 grams of cereals daily in its recommended 300-gram portion of dried dog food. At its pre-dried weight, that equates to 450 grams of fresh meat and 260 grams of cereal. That means that over the course of a year, the average dog eats about 164 kilograms of meat and 95 kilograms of cereals.

According to an article written by Kate Ravilious and published in New Scientist, it takes 43.3 square metres of land to generate 1 kilogram of chicken per year - far more for beef and lamb - and 13.4 square metres to generate a kilogram of cereals. So that gives the average dog a footprint of 0.84 hectares. For a big dog such as a German shepherd, the figure is 1.1 hectares.

Meanwhile, an SUV - the Vales used a 4.6-litre Toyota Land Cruiser in their comparison - driven a modest 10,000 kilometres a year, uses 55.1 gigajoules, which includes the energy required both to fuel and to build it. One hectare of land can produce approximately 135 gigajoules of energy per year, so the Land Cruiser's eco-footprint is about 0.41 hectares - less than half that of a medium-sized dog.

Then there are all the other animals we own. Doing similar calculations for a variety of pets and their foods, the Vales found that cats have an eco-footprint of about 0.15 hectares (slightly less than a Volkswagen Golf), hamsters come in at 0.014 hectares apiece (buy two, and you might as well have bought a plasma TV) and canaries half that. Even a goldfish requires 0.00034 hectares (3.4 square metres) of land to sustain it, giving it an ecological fin-print equal to two cellphones.

This kind of analysis appeals to David Mackay, a physicist at the University of Cambridge and the UK government's new energy adviser. He believes we should put as much thought into choosing a pet as we do into buying a car. He told New Scientist "If a lifestyle choice uses more than 1 per cent of your energy footprint, then it is worthwhile reflecting on that choice and seeing what you can do about it.

"Pets definitely deserve attention: by my estimates, the energy footprint of a cat is about 2 per cent of the average British person's energy footprint - and it's bigger for most dogs."

Source: New Scientist

November 26, 2009