"Challenging the orthodoxies that underpin our entire economic system, this is one subversive read."

Among it findings: the average medium dog kept as a pet requires more land to grow its food than the average person in Vietnam.  According to the book,

"it takes slightly more than 2 acres of land to produce the roughly 360 pounds of meat and 210 pounds of grain [medium sized dogs] consume each year."

But don't fire up the barbecue for canine carnitas just yet. 

It's true that dogs are meat eaters, but they aren't the main drivers of the meat industry.  According to Wikipedia, the ingredients in many dog foods are the stuff we humans won't eat. That includes not only unsavory parts (including bone meal) from healthy animals, but sick animals prohibited from the human food chain. Consider: the meat we buy for ourselves costs more than dog food; a supplier wouldn;t willingly sell prime meat for less money.

"Less expensive dog foods generally include less meat,and more animal by-products and grain fillers."

So are dogs really recycling waste that would otherwise end up somewhere less desireable? 

I don't disagree that dogs have a significant footprint.  A holistic approach to envirnomental improvement would include examining our pets— what they eat and how many we have.  But let's get real about it: in the current system, they're piggybacking on the footprint of us meat eaters.  Kind of like paper towels, which are made from waste paper, or wood pellets for fuel, made from sawdust. 

If we weren't already eating meat, keeping dogs as pets would be decadent, but that's not the case.  As environmental sins go, pets are not at the top of the list.